OpenSS7 Linux Native SCTP

OpenSS7 Linux Native SCTP Installation and Reference Manual

About This Manual

This is Edition 27, last updated 2008-10-31, of The OpenSS7 Linux Native SCTP Installation and Reference Manual, for Version 0.2 release 27 of the OpenSS7 Linux Native SCTP package.

Preface

Notice

This package is released and distributed under the GNU Affero General Public License (see GNU License). Please note, however, that there are different licensing terms for the manual pages and some of the documentation (derived from OpenGroup¹ publications and other sources). Consult the permission notices contained in the documentation for more information.

This manual, is released under the GNU Free Documentation License (see GNU Free Documentation License) with no sections invariant.

Abstract

This manual provides a Installation and Reference Manual for OpenSS7 Linux Native SCTP.

Objective

The objective of this manual is to provide a guide for the STREAMS programmer when developing STREAMS modules, drivers and application programs for OpenSS7 Linux Native SCTP.

This guide provides information to developers on the use of the STREAMS mechanism at user and kernel levels.

STREAMS was incorporated in UNIX System V Release 3 to augment the character input/output (I/O) mechanism and to support development of communication services.

STREAMS provides developers with integral functions, a set of utility routines, and facilities that expedite software design and implementation.

Intent

The intent of this manual is to act as an introductory guide to the STREAMS programmer. It is intended to be read alone and is not intended to replace or supplement the OpenSS7 Linux Native SCTP manual pages. For a reference for writing code, the manual pages (see STREAMS(9)) provide a better reference to the programmer. Although this describes the features of the OpenSS7 Linux Native SCTP package, OpenSS7 Corporation is under no obligation to provide any software, system or feature listed herein.

Audience

This manual is intended for a highly technical audience. The reader should already be familiar with Linux kernel programming, the Linux file system, character devices, driver input and output, interrupts, software interrupt handling, scheduling, process contexts, multiprocessor locks, etc.

The guide is intended for network and systems programmers, who use the STREAMS mechanism at user and kernel levels for Linux and UNIX system communication services.

Readers of the guide are expected to possess prior knowledge of the Linux and UNIX system, programming, networking, and data communication.

Revisions

Take care that you are working with a current version of this manual: you will not be notified of updates. To ensure that you are working with a current version, contact the Author, or check The OpenSS7 Project website for a current version.

A current version of this manual is normally distributed with the OpenSS7 Linux Native SCTP package.

Version Control

     sctp.texi,v
     Revision 0.9.2.28  2008-09-20 11:04:25  brian
     - added package patchlevel
     
     Revision 0.9.2.27  2008-08-03 06:03:27  brian
     - protected agains texinfo commands in log entries
     
     Revision 0.9.2.26  2008/07/27 08:48:51  brian
     - no invariant sections, more libtool ignores
     
     Revision 0.9.2.25  2008-04-29 08:49:51  brian
     - updated headers for Affero release
     
     Revision 0.9.2.24  2008-04-25 11:50:44  brian
     - updates to AGPLv3
     
     Revision 0.9.2.23  2007/08/12 06:43:57  brian
     - updated licenses in manuals
     
     Revision 0.9.2.22  2007/02/28 06:30:29  brian
     - updates and corrections, #ifdef instead of #if
     
     Revision 0.9.2.21  2006/09/18 01:06:21  brian
     - updated manuals and release texi docs
     
     Revision 0.9.2.20  2006/08/28 10:46:54  brian
     - correction
     
     Revision 0.9.2.19  2006/08/28 10:32:45  brian
     - updated references
     
     Revision 0.9.2.18  2006/08/27 12:26:34  brian
     - finalizing auto release files
     
     Revision 0.9.2.17  2006/08/26 09:16:38  brian
     - better release file generation
     
     Revision 0.9.2.16  2006/08/23 11:00:26  brian
     - added preface, corrections and updates for release
     
     Revision 0.9.2.14  2006-03-29 04:27:45 -0700  brian
     - corrections for rerelease, see ChangeLog
     
     Revision 0.9.2.13  2006-03-22 03:01:59 -0700  brian
     - added makefile target index
     
     Revision 0.9.2.12  2006-03-04 22:51:50 -0700  brian
     - minor updates of some release info for next release
     
     Revision 0.9.2.11  2005-07-08 07:15:51 -0600  brian
     - updates to documentation
     
     Revision 0.9.2.10  2005-06-24 07:38:58 -0600  brian
     - added troubleshooting section to manuals
     
     Revision 0.9.2.9  2005-05-14 02:29:32 -0600  brian
     - copyright header correction
     
     Revision 0.9.2.8  2005-04-12 17:01:41 -0600  brian
     - correct docs
     
     Revision 0.9.2.7  2005-04-12 03:28:55 -0600  brian
     - corrections
     
     Revision 0.9.2.6  2005-03-14 17:56:58 -0700  brian
     - Updated version numbering in texinfo files.
     
     Revision 0.9.2.5  2005-03-14 17:51:55 -0700  brian
     - Updated version numbering in texinfo files.
     
     Revision 0.9.2.4  2005-02-17 13:00:07 -0700  brian
     - Fixes for texi documentation.
     
     Revision 0.9.2.3  2005-01-24 04:57:59 -0700  brian
     - Updated texinfo headers.
     
     Revision 0.9.2.2  2004-12-21 15:20:24 -0700  brian
     - Some corrections.
     
     Revision 0.9.2.1  2004-12-20 03:18:19 -0700  brian
     - Big start on autoconf release of Linux Native SCTP.
     
     Revision 0.9  1996-12-31 17:00:00 -0700  brian
     *** empty log message ***

ISO 9000 Compliance

Only the TeX, texinfo, or roff source for this manual is controlled. An opaque (printed, postscript or portable document format) version of this manual is an UNCONTROLLED VERSION.

Disclaimer

OpenSS7 Corporation disclaims all warranties with regard to this documentation including all implied warranties of merchantability, fitness for a particular purpose, non-infringement, or title; that the contents of the manual are suitable for any purpose, or that the implementation of such contents will not infringe on any third party patents, copyrights, trademarks or other rights. In no event shall OpenSS7 Corporation be liable for any direct, indirect, special or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with any use of this manual or the performance or implementation of the contents thereof.

OpenSS7 Corporation reserves the right to revise this software and documentation for any reason, including but not limited to, conformity with standards promulgated by various agencies, utilization of advances in the state of the technical arts, or the reflection of changes in the design of any techniques, or procedures embodied, described, or referred to herein. OpenSS7 Corporation is under no obligation to provide any feature listed herein.

U.S. Government Restricted Rights

If you are licensing this Software on behalf of the U.S. Government ("Government"), the following provisions apply to you. If the Software is supplied by the Department of Defense ("DoD"), it is classified as "Commercial Computer Software" under paragraph 252.227-7014 of the DoD Supplement to the Federal Acquisition Regulations ("DFARS") (or any successor regulations) and the Government is acquiring only the license rights granted herein (the license rights customarily provided to non-Government users). If the Software is supplied to any unit or agency of the Government other than DoD, it is classified as "Restricted Computer Software" and the Government's rights in the Software are defined in paragraph 52.227-19 of the Federal Acquisition Regulations ("FAR") (or any successor regulations) or, in the cases of NASA, in paragraph 18.52.227-86 of the NASA Supplement to the FAR (or any successor regulations).

Acknowledgements

As with most open source projects, this project would not have been possible without the valiant efforts and productive software of the Free Software Foundation and the Linux Kernel Community.

Sponsors

Funding for completion of the OpenSS7 OpenSS7 Linux Native SCTP package was provided in part by:

Additional funding for The OpenSS7 Project was provided by:

Contributors

The primary contributor to the OpenSS7 OpenSS7 Linux Native SCTP package is Brian F. G. Bidulock. The following is a list of significant contributors to The OpenSS7 Project:

Authors

The authors of the OpenSS7 OpenSS7 Linux Native SCTP package include:

See Author Index, for a complete listing and cross-index of authors to sections of this manual.

Maintainer

The maintainer of the OpenSS7 OpenSS7 Linux Native SCTP package is:

Please send bug reports to bugs@openss7.org using the send-pr script included in the package, only after reading the BUGS file in the release, or See Problem Reports.

Web Resources

The OpenSS7 Project provides a website dedicated to the software packages released by the OpenSS7 Project.

Bug Reports

Please send bug reports to bugs@openss7.org using the send-pr script included in the OpenSS7 Linux Native SCTP package, only after reading the BUGS file in the release, or See Problem Reports. You can access the OpenSS7 GNATS database directly via the web, however, the preferred method for sending new bug reports is via mail with the send-pr script.

Mailing Lists

The OpenSS7 Project provides a number of general discussion Mailing Lists for discussion concerning the OpenSS7 OpenSS7 Linux Native SCTP package as well as other packages released by The OpenSS7 Project.

These are mailman mailing lists and so have convenient web interfaces for subscribers to control their settings. See http://www.openss7.org/mailinglist.html.

The mailing lists are as follows:

openss7

The openss7 mailing list is for general enquiries, information exchange and announcements regarding the OpenSS7 Project. This is our original mailing list and takes the highest amount of traffic.

openss7-announce

The openss7-announce mailing list is for announcements related to the OpenSS7 Project. This list will accept announcements posted by subscribers. Subscribe to this list if you are interested in announcements from the OpenSS7 Project, subscribers and sponsors, related to the OpenSS7 Project or STREAMS, SS7, SIGTRAN or SCTP in general.

openss7-cvs

The openss7-cvs mailing list is for automatic CVS log reporting. You must get permission of the owner to subscribe to this list. Subscribers are not allowed to post to this list, this is merely for distributing notification of changes to the CVS repository.h

openss7-develop

The openss7-develop mailing list is for email exchange related to the development projects under the OpenSS7 Project. This includes development requests, proposals, requests for comment or proposal. Subscribe to this list if you are interested in ongoing development details regarding the OpenSS7 Project.

openss7-test

The openss7-test mailing list is for email exchange related to the testing of code under the OpenSS7 Project. This specifically relates to conformance testing, verification testing, interoperability testing and beta testing. Subscribe to this list if you are interested in participating in and receiving ongoing details of test activities under the OpenSS7 Project.

openss7-bugs

The openss7-bugs mailing list is specifically tailored to bug tracking. The mailing list takes a feed from the OpenSS7 GNATS bug tracking system and accepts posting of responses to bug reports, tracking and resolution. Subscribe to this list if you are interested in receiving detailed OpenSS7 release code bug tracking information. This list is not archived; for historical information on problem reports, see our GNATS databases.

openss7-updates

The openss7-updates mailing list provides updates on OpenSS7 Project code releases and ongoing activities. Subscribers are not allowed to post to this list; this list is for official OpenSS7 Project announcements only. Subscribe to this list if you are interested in receiving updates concerning official releases and activities of the OpenSS7 Project.

openss7-streams

The openss7-streams mailing list is for email exchange related to the STREAMS development projects under the OpenSS7 Project. This includes development requests, proposals, requests for comment or proposal. Subscribe to this list if you are interested in ongoing development details regarding the OpenSS7 Project STREAMS components.

linux-streams

The linux-streams mailing list is for mail exchange related to Linux Fast-STREAMS or Linux STREAMS. This includes patches, development requests, proposals, requests for comment or proposal. Subscribe to this list if you are interested in ongoing development details regarding the STREAMS for Linux components. This is the the new (September 2006) home of the linux-streams list formerly of <gsyc.escet.urjc.es>.

Spam

To avoid spam being sent to the members of the OpenSS7 mailing list(s), we have blocked mail from non-subscribers. Please subscribe to the mailing list before attempting to post to them. (Attempts to post when not subscribed get bounced.)

As an additional measure against spam, subscriber lists for all OpenSS7 mailing lists are not accessible to non-subscribers; for most lists subscriber lists are only accessible to the list administrator. This keeps your mailing address from being picked off our website by bulk mailers.

Acceptable Use Policy

It is acceptable to post professional and courteous messages regarding the OpenSS7 package or any general information or questions concerning STREAMS, SS7, SIGTRAN, SCTP or telecommunications applications in general.

Large Attachments

The mailing list is blocked from messages of greater than 40k. If you have attachments (patches, test programs, etc.) and you mail them to the list, it will bounce to the list administrator. If you are interested in making your patches, test programs, test results or other large attachments available to the members of the mailing list, state in the message that you would like them posted and the list administrator will place them in the mail archives.

Quick Start Guide

OpenSS7 Linux Native SCTP

Package sctp-0.2.27 was released under AGPLv3 2008-10-31.

The OpenSS7 Linux Native SCTP package is the OpenSS7 Linux Native (Sockets) Kernel implementation of Stream Control Transmission Protocol (SCTP).

sctp-0.2.27 is the 0.2.27 version of a Linux Kernel native implementation of RFC 2960 Stream Control Transmission Protocol. For information on using the implementation see the man/sctp.7 Linux manual page and look at the test programs in sctp-0.2.27/test/.

Warning: This is pre-release code. It is Beta but rather stable. Nevertheless, it is possible it will crash or lock your machine in some situations. Please remember that there is NO WARRANTY with this code and take appropriate precautions when attempting to run it.

This distribution is only currently applicable to Linux 2.4 kernels and was targeted at ix86, x86_64, ppc and ppc64 architectures, but should build and install for other architectures as well.

Release

This is the sctp-0.2.27 package, released 2008-10-31. This ‘0.2.27’ release, and the latest version, can be obtained from the download area of The OpenSS7 Project website using a command such as:

     $> wget http://www.openss7.org/tarballs/sctp-0.2.27.tar.bz2

The release is available as an autoconf(1) tarball, src.rpm or dsc, as a set of binary rpms or debs, or as a yum(8) or apt(8) repository. See the download page for the autoconf(1) tarballs, src.rpms, dscs, or repository access instructions. See the sctp package page for tarballs, source and binary packages.

Please see the NEWS file for release notes and history of user visible changes for the current version, and the ChangeLog file for a more detailed history of implementation changes. The TODO file lists features not yet implemented and other outstanding items.

Please see the INSTALL, INSTALL-sctp and README-make, files (or see Installation) for installation instructions.

When working from cvs(1) or git(1), please see the README-cvs, file (or see Downloading from CVS). An abbreviated installation procedure that works for most applications appears below.

This release of the package is published strictly under Version 3 of the GNU Affero Public License which can be found in the file COPYING. Package specific licensing terms (if any) can be found in the file LICENSES. Please respect these licensing arrangements. If you are interested in different licensing terms, please contact the copyright holder, or OpenSS7 Corporation <sales@openss7.com>.

See README-alpha (if it exists) for alpha release information.

Prerequisites

The quickest and easiest way to ensure that all prerequisites are met is to download and install this package from within the OpenSS7 Master Package, openss7-0.9.2.G, instead of separately.

Prerequisites for the OpenSS7 Linux Native SCTP package are as follows:

1. Linux distribution, somewhat Linux Standards Base compliant, with a 2.4 or 2.6 kernel and the appropriate tool chain for compiling out-of-tree kernel modules. Most recent Linux distributions are usable out of the box, but some development packages must be installed. For more information, see Compatibility.

   	− A fairly LSB compliant GNU/Linux distribution.2
   	− Linux 2.4 kernel (2.4.10 - 2.4.27).
   	− glibc2 or better.
   	− GNU groff (for man pages).3
   	− GNU texinfo (for info files).

When configuring and building multiple OpenSS7 Project release packages, place all of the source packages (unpacked tarballs) at the same directory level and all build directories at the same directory level (e.g. all source packages under /usr/src).

When installing packages that install as kernel modules, it is necessary to have the correct kernel development package installed. For the following distributions, use the following commands:

     Ubuntu:  $> apt-get install linux-headers
     Debian:  $> apt-get install kernel-headers
     Fedora:  $> yum install kernel-devel

You also need the same version of gcc(1) compiler with which the kernel was built. If it is not the default, add ‘CC=kgcc’ on the line after ‘./configure’, for example:

     $> ../sctp-0.2.27/configure CC='gcc-3.4'

Installation

The following commands will download, configure, build, check, install, validate, uninstall and remove the package:

     $> wget http://www.openss7.org/tarballs/sctp-0.2.27.tar.bz2
     $> tar -xjvf sctp-0.2.27.tar.bz2
     $> mkdir build
     $> pushd build
     $> ../sctp-0.2.27/configure --enable-autotest
     $> make
     $> make check
     $> sudo make install
     $> sudo make installcheck
     $> sudo make uninstall
     $> popd
     $> sudo rm -rf build
     $> rm -rf sctp-0.2.27
     $> rm -f sctp-0.2.27.tar.bz2

If you have problems, try building with the logging targets instead. If the make of a logging target fails, an automatic problem report will be generated that can be mailed to The OpenSS7 Project.⁴ Installation steps using the logging targets proceed as follows:

     $> wget http://www.openss7.org/tarballs/sctp-0.2.27.tar.bz2
     $> tar -xjvf sctp-0.2.27.tar.bz2
     $> mkdir build
     $> pushd build
     $> ../sctp-0.2.27/configure --enable-autotest
     $> make compile.log
     $> make check.log
     $> sudo make install.log
     $> sudo make installcheck.log
     $> sudo make uninstall.log
     $> popd
     $> sudo rm -rf build
     $> rm -rf sctp-0.2.27
     $> rm -f sctp-0.2.27.tar.bz2

See README-make for additional specialized make targets.

For custom applications, see the INSTALL and INSTALL-sctp files or the see Installation, as listed below. If you encounter troubles, see Troubleshooting, before issuing a bug report.

Brief Installation Instructions

The OpenSS7 Linux Native SCTP package is available from the downloads area of The OpenSS7 Project website using a command such as:

     $> wget http://www.openss7.org/tarballs/sctp-0.2.27.tar.bz2

Unpack the tarball using a command such as:

     $> tar -xjvf sctp-0.2.27.tar.bz2

The tarball will unpack into the relative subdirectory named after the package name: sctp-0.2.27.

The package builds using the GNU autoconf utilities and the configure script. To build the package, we recommend using a separate build directory as follows:

     $> mkdir build
     $> cd build
     $> ../sctp-0.2.27/configure

In general, the package configures and builds without adding any special options to the configure script. For general options to the configure script, see the GNU INSTALL file in the distribution:

     $> less ../sctp-0.2.27/INSTALL

For specific options to the configure script, see the INSTALL-sctp file in the distribution, or simply execute the configure script with the --help option like so:

     $> ../sctp-0.2.27/configure --help

After configuring the package, the package can be compiled simply by issuing the ‘make’ command:

     $> make

Some specialized makefile targets exists, see the README-make file in the distribution or simply invoke the ‘help’ target like so:

     $> make help | less

After successfully building the package, the package can be checked by invoking the ‘check’ make target like so:

     $> make check

After successfully checking the package, the package can be installed by invoking the ‘install’ make target (as root) like so:

     $> sudo make install

The test suites that ship with the package can be invoked after the package has been installed by invoking the ‘installcheck’ target. This target can either be invoked as root, or as a normal user, like so:

     $> make installcheck

(Note: you must add the --enable-autotest flag to configure, above for the test suites to be invoked with ‘make installcheck’.)

The package can be cleanly removed by invoking the ‘uninstall’ target (as root):

     $> sudo make uninstall

Then the build directory and tarball can be simply removed:

     $> cd ..
     $> rm -rf build
     $> rm -rf sctp-0.2.27
     $> rm -f sctp-0.2.27.tar.bz2

Detailed Installation Instructions

More detailed installation instructions can be found in the Installation, contained in the distribution in ‘text’, ‘info’, ‘html’ and ‘pdf’ formats:

     $> cd ../sctp-0.2.27
     $> less doc/manual/sctp.txt
     $> lynx doc/manual/sctp.html
     $> info doc/manual/sctp.info
     $> xpdf doc/manual/sctp.pdf

The ‘text’ version of the manual is always available in the MANUAL file in the release.

The current manual is also always available online from The OpenSS7 Project website at:

     $> lynx http://www.openss7.org/sctp_manual.html

1 Introduction

This manual documents the design, implementation, installation, operation and future development schedule of the OpenSS7 Linux Native SCTP package.

1.1 Overview

This manual documents the design, implementation, installation, operation and future development of the OpenSS7 Linux Native SCTP package.

The OpenSS7 Linux Native SCTP package is an Open Linux SCTP package for Linux. It includes development tools, header files and manual pages for SCTP.

The OpenSS7 Linux Native SCTP package is essential to the development and support of SCTP networking modules and drivers and provides a fundamental set of header files and manual pages for such development.

1.2 Organization of this Manual

This manual is organized (loosely) into several sections as follows:

1.3 Conventions and Definitions

This manual uses texinfo typographic conventions.

2 Objective

3 Reference

3.1 Files

SCTP creates the following kernel modules files in the kernel modules directory, /lib/modules/2.4.20-28.7/:⁵

modules.sctp

SCTP installs the following kernel module files in the kernel modules directory, /lib/modules/2.4.20-28.7/kernel/net/ipv4/:⁶

sctp.o

This kernel module contains the SCTP protocol module.

SCTP installs the following header files in the system include directory, /usr/include/netinet/:

sctp.h

This file contains SCTP and socket option definitions.

SCTP installs the following test programs in the system libexec directory, /usr/libexec/sctp/:⁷

send-pr

send-pr.config

The send-pr stand-alone shell script can be used for the automatic generation of problem reports for the OpenSS7 Linux Native SCTP package. The send-pr.config file provides localized definitions used by the send-pr program. For more information on problem reports, See Problem Reports, and, in particular, See Stand Alone Problem Reports.

test-sctp-dc

This binary contains a test program for delay test client for SCTP.

test-sctp-ds

This binary contains a test program for delay test server for SCTP.

test-sctp-sc

This binary contains a test program for socket test client for SCTP.

test-sctp-ss

This binary contains a test program for socket test server for SCTP.

test-sctp-tc

This binary contains a test program for throughput test client for SCTP.

test-sctp-ts

This binary contains a test program for throughput test server for SCTP.

test-sctpc

This binary contains a test program for a general testing test client for SCTP.

test-sctps

This binary contains a test program for a general testing test server for SCTP.

test-tcp-dc

This binary contains a test program for delay test client for TCP.

test-tcp-ds

This binary contains a test program for delay test server for TCP.

test-tcp-tc

This binary contains a test program for throughput test client for TCP.

test-tcp-ts

This binary contains a test program for throughput test server for TCP.

test-tcpc

This binary contains a test program for a general testing test client for TCP.

test-tcps

This binary contains a test program for a general testing test server for TCP.

test-udpc

This binary contains a test program for a general testing test client for UDP.

test-udps

This binary contains a test program for a general testing test server for UDP.

testsuite

atlocal

The testsuite stand-alone shell script invokes test cases in the test programs above as compiled into a comprehensive regression, troubleshooting and validation test suite for the OpenSS7 Linux Native SCTP drivers. The atlocal file provides localized definitions used by the testsuite program. For more information on test suites, See Test Suites, and, in particular, See Running Test Suites.

SCTP installs the following init scripts in the system init directory, /etc/rc.d/init.d/ (non-Debian) or /etc/init.d/ (Debian):

sctp

This is the name of the system init script on non-Debian based systems.

sctp.sh

This is the name of the system init script on Debian based systems.

SCTP installs the following system configuration files in the configuration directory, /etc/:

sctp.conf

This file provided configuration information for any system controls affected by the ‘SCTP’ package.

modutils/sctp

This file provides module definitions and demand loading aliases for the sctp package. This file is really only applicable to older 2.4 kernels.

SCTP installs the following system configuration file in the system configuration directory, /etc/sysconfig/ (non-Debian) or /etc/default/ (Debian):

sctp

This file provides system configuration information used by init scripts for the ‘SCTP’ package. Some options of init script execution can be controlled by this file.

SCTP installs the following info files in the system info directory, /usr/share/info/:

sctp.info

sctp.info-1

sctp.info-2

These files contain this manual in GNU info format.

SCTP installs the following manual page macros and reference database files in the system man directory, /usr/share/man/:⁸

sctp.macros

This file contains manual page macro definitions included by the manual pages included in the package.

sctp.refs

This file contains a reference database referenced by the manual pages included in the package.

SCTP installs the following manual pages in the system man directory, /usr/share/man/man7/:

sctp.7

This is the SCTP manual page.

SCTP installs the following manual pages in the system man directory, /usr/share/man/man8/:

test-sctp-dc.8

test-sctp-ds.8

test-sctp-sc.8

test-sctp-ss.8

test-sctp-tc.8

test-sctp-ts.8

test-sctpc.8

test-sctps.8

test-tcp-dc.8

test-tcp-ds.8

test-tcp-tc.8

test-tcp-ts.8

test-tcpc.8

test-tcps.8

test-udpc.8

test-udps.8

These are the test program manual pages.

3.2 Kernel Modules

3.2.1 Stream Control Transmission Protocol (SCTP) Module (sctp)

Licensing

The sctp module was originally written by Brian F. G. Bidulock and is licensed under the GNU Affero General Public License Version 3 See GNU Affero General Public License.

3.3 Libraries

3.4 Utilities

3.4.1 test-sctp-dc

Note that test-sctp-dc is maintained as a manual page, test-sctp-dc(8).

3.4.2 test-sctp-ds

Note that test-sctp-ds is maintained as a manual page, test-sctp-ds(8).

3.4.3 test-sctp-sc

Note that test-sctp-sc is maintained as a manual page, test-sctp-sc(8).

3.4.4 test-sctp-ss

Note that test-sctp-ss is maintained as a manual page, test-sctp-ss(8).

3.4.5 test-sctp-tc

Note that test-sctp-tc is maintained as a manual page, test-sctp-tc(8).

3.4.6 test-sctp-ts

Note that test-sctp-ts is maintained as a manual page, test-sctp-ts(8).

3.4.7 test-sctpc

Note that test-sctpc is maintained as a manual page, test-sctpc(8).

3.4.8 test-sctps

Note that test-sctps is maintained as a manual page, test-sctps(8).

3.4.9 test-tcp-dc

Note that test-tcp-dc is maintained as a manual page, test-tcp-dc(8).

3.4.10 test-tcp-ds

Note that test-tcp-ds is maintained as a manual page, test-tcp-ds(8).

3.4.11 test-tcp-tc

Note that test-tcp-tc is maintained as a manual page, test-tcp-tc(8).

3.4.12 test-tcp-ts

Note that test-tcp-ts is maintained as a manual page, test-tcp-ts(8).

3.4.13 test-tcpc

Note that test-tcpc is maintained as a manual page, test-tcpc(8).

3.4.14 test-tcps

Note that test-tcps is maintained as a manual page, test-tcps(8).

3.4.15 test-udpc

Note that test-udpc is maintained as a manual page, test-udpc(8).

3.4.16 test-udps

Note that test-udps is maintained as a manual page, test-udps(8).

3.5 Development

OpenSS7 Linux Native SCTP does not currently install any libraries. The socket library normally available under Linux in libc are sufficient. OpenSS7 Linux Native SCTP does, however, install the /usr/include/netinet/sctp.h header file for development of applications programs that use the sctp kernel module.

3.6 SCTP Reference Page

NAME

sctp - Stream Control Transmission Protocol (SCTP).

SYNOPSIS

     #include <sys/socket.h>
     #include <netinet/in.h>
     #include <netinet/sctp.h>
     
     sctp_socket = socket(PF_INET, SOCK_SEQPACKET, 0);
     sctp_socket = socket(PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
     sctp_socket = socket(PF_INET, SOCK_STREAM, IPPROTO_SCTP);
     sctp_socket = socket(PF_INET, SOCK_RDM, 0IPPROTO_SCTP

DESCRIPTION

SCTP is an implementation of the SCTP (Stream Control Transmission Protocol) defined in RFC 2960. SCTP provides reliable delivery of ordered or unordered packets over a full duplex connection between two ‘SOCK_SEQPACKET’ sockets on top of ip(7). SCTP can guarantee that the data arrives in order on a stream, if requested, and retransmits lost packets. It generates and checks a per packet checksum to catch transmission errors.

SCTP provides the following socket types:

‘SOCK_SEQPACKET’

A standard ‘SOCK_SEQPACKET’ socket that preserves message boundaries, Nagles at the association level, and provides ordered and unordered reliable and partial reliable, acknowledged and unacknowledged delivery on multiple streams.

‘SOCK_STREAM’

A tcp(7) compatible ‘SOCK_STREAM’ socket that does not preserve message boundaries, Nagles at the stream level, and provides ordered and out-of-band unacknowledged delivery on a single stream. This is an optional capability of SCTP which provides for maximum compatibility with applications written for tcp(7). This socket type is available when SCTP is compiled with the kernel configuration parameter ‘CONFIG_SCTP_TCP_COMPATIBLE’ set.

‘SOCK_RDM’

An udp(7) compatible ‘SOCK_RDM’ socket that preserves message boundaries, does not Nagle, and provides only unordered but reliable or partially reliable delivery on multiple streams. This is an optional capability of SCTP which provides for maximum compatibility with applications written for udp(7). This socket type is available when SCTP is compiled with the kernel configuration parameter ‘CONFIG_SCTP_UDP_COMPATIBLE’ set.

Connection Establishment

A fresh SCTP socket has no remote or local address and is not fully specified. To create an outgoing SCTP association use connect(2) to establish an association with another SCTP endpoint. To receive incoming associations bind(2) the socket first to a number of local addresses and a port and then call listen(2) to put the socket into listening state. Then a new socket for each incoming association can be accepted using accept(2). A socket that has had accept(2) or connect(2) successfully called on it is fully specified and may transmit data. Data cannot be transmitted on listening or not yet connected sockets.

SCTP supports large windows to support links with high latency or bandwidth. Large SCTP windows can be used by increasing the send and receive buffer sizes. They can be set globally with the ‘net.core.wmem_default’ and ‘net.core.rmem_default’ system controls, or on individual sockets by using the ‘SO_SNDBUF’ and ‘SO_RCVBUF’ socket options. The maximum sizes for socket buffers are limited by the ‘net.core.wmem_max’ and ‘net.core.rmem_max’ system controls. See socket(7) for more information.

Sending Data

When sending data, the specific destination address within the association to which to send the data can be specified by providing a valid destination address as an argument to sendto(2) or sendmsg(2). Data sent with send(2) or write(2) will use SCTP's destination transport address selection policies for transmission and retransmission to single- and multi-homed hosts. The stream upon which to send the data can also be set with the ‘SCTP_SID’ socket option on a socket basis with setsockopt(2) or on a per-message basis with ‘SCTP_SID’ control message to sendmsg(2). In addition, the ip(7) ‘IP_PKTINFO’ option can be used with sendmsg(2) to specify the interface, first-hop destination address and source address to be used in the outbound packet on ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets. IP options can also be specified for the outbound packet with the ip(7) ‘IP_OPTIONS’ or ‘IP_RETOPTS’ control messages to sendmsg(2).

For ‘SOCK_SEQPACKET’ socket, send operations may also use the ‘MSG_MORE’ flag when sending with send(2), sendto(2) or sendmsg(2) to indicate that the next write operation will provide additional data belonging to the same packet. ‘SOCK_STREAM’ sockets do not support send options and do not return the ‘MSG_TRUNC’ flag on send operations.

If a ‘SOCK_SEQPACKET’ or ‘SOCK_STREAM’ socket does not have sufficient room to buffer the sent data, it buffers what it can and returns the amount of user data buffered. ‘SOCK_RDM’ sockets wait for sufficient room to buffer the entire sent packet before returning. ‘SOCK_SEQPACKET’ and ‘SOCK_STREAM’ sockets will segment large data writes in to smaller segments for delivery to the peer.

SCTP provides a mechanism for receiving positive and negative acknowledgements of sent data on ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets. When the socket option ‘SCTP_DISPOSITION’ is set to ‘SCTP_DISPOSITION_ACKED’, or when data is sent using the ‘MSG_CONFIRM’ flag to send(2), sendto(2) or sendmsg(2), message confirmation or delivery failures can be received by passing the ‘MSG_CONFIRM’ flag to recv(2), recvfrom(2) or recvmsg(2). This mechanism also provides for retrieval and disposition of undelivered messages after the association has aborted or shut down, but before a call to close(2).

Receiving Data

For ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets, all receive operations return only one packet, or a portion of one packet. When the packet is smaller than the passed buffer only that much data is returned, when it is larger the packet is truncated and the ‘MSG_TRUNC’ flag is set for ‘SOCK_RDM’ sockets. Subsequent recv or read(2), or a subsequent recvfrom(2) or recvmsg(2) for the same stream will return the remainder of the packet for ‘SOCK_SEQPACKET’ sockets. ‘SOCK_SEQPACKET’ sockets also return the ‘MSG_EOR’ flag when the end of the packet has been received successfully. For ‘SOCK_STREAM’ sockets, all receive operations return only the amount of data available on the current stream. ‘MSG_TRUNC’ and ‘MSG_EOR’ are never set for ‘SOCK_STREAM’ sockets.

IP options may be sent or received using the socket options described in ip(7). They are only processed by the kernel when the appropriate system control is enabled (but still passed to the user even when it is turned off). See ip(7).

When the ‘MSG_DONTROUTE’ flag is set on sending, the destination address must refer to a local interface address and the packet is only sent to that interface.

SCTP fragments a packet when its total length exceeds the association MTU (Maximum Transmission Unit). A more network friendly alternative is to use path MTU discovery as described in the ‘IP_PMTU_DISCOVER’ section of ip(7).

SCTP supports urgent data similar to tcp(7). Urgent data is used to signal the receiver that some important message is part of the data stream and that it should be processed as soon as possible. Urgent data is always sent out of order. To send urgent (or out of order) data specify the ‘MSG_OOB’ option to send(2), sendto(2), or sendmsg(2). When urgent data is received, the kernel sends a ‘SIGURG’ signal to the reading process or the process or process group that has been set for the socket using the ‘FIOCSPGRP’ or ‘FIOCSETOWN’ I/O controls. When the ‘SO_OOBINLINE’ socket option is enabled, urgent data is put into the normal data stream (and can be tested for by the ‘SIOCATMARK’ I/O control), otherwise it can only be received when the ‘MSG_OOB’ flag is set for recvmsg(2).

ADDRESS FORMATS

SCTP is built on top of IP (see ip(7)). The address formats defined by ip(7) apply to SCTP. SCTP uses the IPv4 sockaddr_in address format described in ip(7).

SCTP supports multiple-stream point-to-point communication within multi-homed associations; broadcasting and multi-casting are not supported.

In addition to normal IP addressing, SCTP provides extensions on the bind(2), accept(2), connect(2), getsockname(2), and getpeername(2) system calls. These functions normally take or return a single sockaddr_in as an address argument. When used in conjunction with an SCTP socket on or to a multi-homed host, these calls will accept or return an array of sockaddr_in structures. The number of addresses in the structure is indicated by the length of the structure and the protocol family of the socket. SCTP will only support one port number being specified in the address list, and each sockaddr_in structure in the list must contain the same sin_port. (Note: Linux uses ‘MAX_SOCK_ADDR’ as a maximum size of the socket address length. This is currently only 128 bytes or eight (8) sockaddr_in structures. Eight (8) addresses should be sufficient for most applications.)

Multiple addresses provided to the bind(2) system call will be interpreted as multiple local addresses to provide to the peer at connection time as well as the local address/port combinations upon which a listening socket will accept incoming associations. A call to accept(2) requesting the source address of the peer will return multiple transport addresses if the connecting peer is multi-homed. Multiple addresses provided to the connect(2) system call will be interpreted as multiple destination address/port combinations to which to attempt to form an association. The getpeername(2) system call returns the list of destination address/port combinations to which the socket is connected. The getsockname(2) system call returns the list of local address/port combinations to which the socket is bound.

getsockname(2)

A call to getsockname(2) can provide multiple bound transport addresses for a multi-homed host when the socket is bound to multiple addresses or ‘INADDR_ANY’ using bind(2). The first address in the list is the primary address to which the socket is bound. This is the first address that will be attempted to be used as a source address when sending an INIT chunk to the SCTP peer as a result of a call to connect(2). Otherwise, the order of the addresses has no significance. When the socket is not bound to any address, the call to getsockname(2) returns a socket address with address family ‘AF_UNSPEC’.

As a result of binding to ‘INADDR_ANY’ or the ADD-IP extension, subsequent calls to getsockname(2) may return different addresses depending on the state of the connection or resulting from the exchange of ASCONF control chunks. This list of transport addresses returned by getsockname(2) represents the current list of local transport addresses bound to the endpoint. When the connection is multi-homed or supports ADD-IP, this behaviour is different from tcp(7) and other connection-oriented protocols, whose bound address does not change during the lifespan of a connection.

getpeername(2)

A call to getpeername(2) can provide multiple peer transport addresses for a multi-homed peer when the socket is connecting or connected to multiple addresses using connect(2). The first address is always the current primary destination transport address. The current primary destination transport address is the address to which all messages will be sent in the absence of congestion or failure.

As a result of connecting to multiple transport addresses using connect(2) or the ADD-IP extension, the membership of the list of transport addresses returned by getpeername(2) may change due to the state of the socket or resulting from the exchange of ASCONF control chunks. When the SCTP connection is multi-homed or supports ADD-IP, this behaviour is different from tcp(7) and other connection-oriented protocol, whose peer address does not change during the lifespan of a connection.

SOCKET CALLS

Socket calls for ‘SOCK_STREAM’, ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets are different in some respects (addressing and options) than their tcp(7) or udp(7) counterparts. These differences are described here. For common behaviour, please see the indicated manual page in Section 2.

bind(2)

A call to bind(2) can provide multiple address if the host is multi-homed. Binds to ‘INADDR_ANY’ will result in a binding to all of the local transport addresses belonging to the host that do not cause a conflict at the time that a connection is formed. As with other sockets, the local port number is assigned at the time that bind(2) is called.

As with other sockets, binding to a socket address with address family ‘AF_UNSPEC’ will cause the socket to be unbound from all transport addresses.

Consistent with tcp(7), SCTP supports binding of multiple sockets to the same transport address providing that the socket option ‘SO_REUSEADDR’ (see socket(7)) is set on the sockets and that no sockets have executed listen(2) bound to the same transport address.

accept(2)

A call to accept(2) requesting the peer address of the connection will return multiple transport addresses if the connecting peer is multi-homed. The first transport address in the list is the primary transport address of the connecting peer. The primary transport address is the address upon which the INIT message was received. Otherwise, the accept(2) operation is unchanged.

connect(2)

A call to connect(2) can provide multiple destination transport addresses if the peer host is multi-homed. If an INIT chunk sent to the first destination transport address is not acknowledged, the next INIT chunk will be sent to the next address in the list. This will occur until an acknowledgement is received from one of the addresses or the connection attempt times out. Each address will be retried sctp_max_init_retries times before the connection process is considered to have timed out. Broadcast and multicast addresses are permitted for the call to connect(2) but will not form an endpoint address in the association. This feature permits fast and reliable initialization of associations.

As with other connection-oriented sockets, connecting to a socket address with address family ‘AF_UNSPEC’ will cause a socket engaged in active connections to be disconnected.

read(2)

recv(2)

recvfrom(2)

recvmsg(2)

SCTP preserves message boundaries on read for ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets. Message boundaries are never preserved for ‘SOCK_STREAM’ sockets.

The following message flags to, or returned from, recv(2), recvfrom(2) and recvmsg(2) have special interpretations for SCTP:

‘MSG_OOB’

SCTP supports the return of the ‘MSG_OOB’ flag from recv(2), recvfrom(2) and recvmsg(2). Data read with the ‘MSG_OOB’ flag set indicates that the data was received on the specified SCTP stream with the Unordered bit set. Operation is similar to tcp(7).

‘MSG_EOR’

For ‘SOCK_SEQPACKET’ sockets, the ‘MSG_EOR’ flag returned from recv(2), recvfrom(2) or recvmsg(2) indicates that the data read has been read to the end of a record. The ‘MSG_EOR’ flag is not used for ‘SOCK_STREAM’ or ‘SOCK_RDM’ sockets.

‘MSG_TRUNC’

SCTP supports the use of the ‘MSG_TRUNC’ flag to recv(2), recvfrom(2) and recvmsg(2). Data read with the ‘MSG_TRUNC’ flag set will return the number of bytes available in the packet rather than the number of bytes read.

When the ‘MSG_TRUNC’ flag is returned from recv(2), recvfrom(2) and recvmsg(2), it indicates that the record was truncated. ‘MSG_TRUNC’ will only be returned on ‘SOCK_RDM’ sockets. ‘MSG_TRUNC’ is never set on return for ‘SOCK_STREAM’ and ‘SOCK_SEQPACKET’ sockets.

‘MSG_CONFIRM’

SCTP supports the use of the ‘MSG_CONFIRM’ flag to recv(2), recvfrom(2) and recvmsg(2). Data read with the ‘MSG_CONFIRM’ flag set will return messages receipt acknowledgements as well as messages which have exceeded their life-times, messages which have been dropped by PR-SCTP, and messages held for retrieval after abort or shutdown.

When the ‘MSG_CONFIRM’ flag is returned from recv(2), recvfrom(2) and recvmsg(2), it indicates that the read data represents data that was confirmed as acknowledged by the peer. See also ‘SCTP_DISPOSITION’ under SOCKET OPTIONS.

Other message flags have the same interpretation as described in recv(2), recvfrom(2) and recvmsg(2).

write(2)

send(2)

sendto(2)

sendmsg(2)

SCTP preserves message boundaries on write for ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets. Message boundaries are never preserved for ‘SOCK_STREAM’ sockets.

The following message flags to send(2), sendto(2) and sendmsg(2) have special interpretations for SCTP:

‘MSG_OOB’

SCTP supports the use of the ‘MSG_OOB’ flag to send(2), sendto(2) and sendmsg(2). Data written with the ‘MSG_OOB’ flag set indicates that the data is to be sent on the specified SCTP stream with the Unordered bit set.

‘MSG_MORE’

SCTP supports the use of the ‘MSG_MORE’ flag to send(2), sendto(2) and sendmsg(2). Data written with the ‘MSG_MORE’ flag set indicates that the data of a subsequent send operation on the same stream contains additional data belonging to the same record. Use of the ‘MSG_MORE’ flag is only supported for ‘SOCK_SEQPACKET’ sockets. Data written with write(2) is assumed to contain an entire record.

‘MSG_PROBE’

SCTP supports the use of the ‘MSG_PROBE’ flag to send(2), sendto(2) and sendmsg(2). Data written with the ‘MSG_PROBE’ flag set indicates that the data is to be used to fill out the heartbeat data in a HEARTBEAT chunk and request that SCTP send a HEARTBEAT to the peer. Use of the ‘MSG_PROBE’ flag is supported on all socket types.

‘MSG_EOF’

SCTP supports the use of the ‘MSG_EOF’ flag to send(2), sendto(2) and sendmsg(2). Data written with the ‘MSG_EOF’ flag will be the last data sent on the association and then a shutdown initiated.

‘MSG_CONFIRM’

SCTP supports the use of the ‘MSG_CONFIRM’ flag to send(2) sendto(2) and sendmsg(2) for ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets. Records or packets written with the ‘MSG_CONFIRM’ flag set are marked for acknowledgement. Acknowledgements can be received with the ‘MSG_CONFIRM’ flag to recv(2), recvfrom(2) and recvmsg(2) as described above. See also ‘SCTP_DISPOSITION’ under SOCKET OPTIONS.

Other message flags have the same interpretation as described in send(2), sendto(2) and sendmsg(2).

shutdown(2)

close(2)

SCTP supports orderly release using shutdown(2) and both orderly and abortive release using close(2) similar to tcp(7).

When the ‘SHUT_RD’ flag is given to shutdown(2), receive will be disabled locally and further receive operations on the socket will fail. When the ‘SHUT_WR’ or ‘SHUT_RDWR’ flag is given to shutdown(2), orderly release will be initiated and further send operations on the socket will fail.

Distinctions between orderly and abortive release when close(2) or exit(2) are called are similar to that of tcp(7).

FEATURES

SCTP provides the following basic features:

• Compiled into kernel or as a loadable module.
• Standards support for socket type ‘SOCK_SEQPACKET’.
• Supports a partial packet delivery interface on all packets. ‘MSG_TRUNC’ set when receiving a packet does not discard the remainder of the packet but permits subsequent reads to read the remainder of the packet.
• Silly Window Syndrome (SWS) avoidance per RFC 1122. Section 4.2.3.2 and 4.2.3.3 as recommended in the SCTP Implementor's Guide.
• Nagle algorithm per RFC 896 and RFC 1122. Section 4.2.3 with delayed ACK modifications presented by Minshall in <draft-minshall-tsvwg-nagle-01.txt>.
• Message disposition and retrieval on connection shutdown or abort, lifetime expiry, and receipt confirmation acknowledgement.
• Support for hardware assisted checksum for drivers which support ‘NETIF_F_HW_CSUM’.
• Support for hardware assisted scatter/gather and fragmentation for devices which support ‘NETIF_F_SG’ and ‘NETIF_F_FRAGLIST’.
• For security of HMACs, SCTP includes a re-keying algorithm for secret keys that rotates secret keys after the key's first cookie lifetime to provide for maximum security for HMACs.
• High performance routing algorithm alters multi-homed routes on a per-packet basis.
• Wide range of settings for timers and protocol parameters permitting fast (average 5ms with 100Hz tick clock; 0.5ms with 1000Hz tick clock) fail-over between failed destination addresses on high-speed networks.
• Deferral of checksum calculation until after socket lookup for protection from software checksum DoS attacks.
• Support for the changes and modifications in the SCTP Implementers Guide <rfc4460.txt>. (See CAVEATS.).

SCTP provides the following added features:

• A tcp(7)-compatible mode for sockets of type ‘SOCK_STREAM’ when SCTP is compiled with kernel configuration parameter ‘CONFIG_SCTP_TCP_COMPATIBLE’ set.
• A udp(7)-compatible mode for sockets of type ‘SOCK_RDM’ when SCTP is compiled with kernel configuration parameter ‘CONFIG_SCTP_UDP_COMPATIBLE’ set.
• Support for both Adler32 and CRC-32c checksums with automatic detection of checksum on receive when SCTP is compiled with kernel configuration parameters ‘CONFIG_SCTP_ADLER_32’ or ‘CONFIG_SCTP_CRC_32C’ set.
• Support for multiple HMAC types when compiled with kernel configuration parameters ‘CONFIG_SCTP_HMAC_SHA_1’ or ‘CONFIG_SCTP_HMAC_MD5’.
• Support for RFC 2960 Appendix A and RFC 3168 compatible Explicit Congestion Notification when compiled with kernel configuration parameter ‘CONFIG_SCTP_ECN’ set.
• Support for <draft-ietf-tsvwg-addip-sctp-08.txt> Adaptation Layer Indication when compiled with kernel configuration parameter ‘CONFIG_SCTP_ADAPTATION_LAYER_INFO’ set.
• Support for ADD-IP extensions from <draft-ietf-tsvwg-addip-sctp-08.txt> when compiled with kernel configuration parameter ‘CONFIG_SCTP_ADD_IP’ set.
• Support for PR-SCTP extensions as described in RFC 3758 when compiled with kernel configuration parameter ‘CONFIG_SCTP_PARTIAL_RELIABILITY’ set.

SYSCTLS

SCTP provides and supports a number of system controls that can be accessed using the /proc/sys/net/ipv4/* files, with the sysctl(2) interface or using sysctl(8).

SCTP supports all socket(7) system controls rmem_default, rmem_max, wmem_default, wmem_max, msg_cost, msg_burst, netdev_max_backlog and optmem_max in the normal fashion. For more information, see socket(7).

SCTP supports ip(7) system controls ip_default_ttl, ip_dynaddr, ip_autoconfig, ip_local_port_range and ip_no_pmtu_disc in the normal fashion. ip(7) system controls ip_forward, ipfrag_high_thresh, ipfrag_low_thresh and ip_always_defrag are not applicable to SCTP. For more information, see ip(7).

The following SCTP specific system controls are provided by SCTP:

sctp_csum_type

Defines the default checksum algorithm that will be used when checksumming packets associated with a socket. Valid values are as follows:

SCTP_CSUM_ADLER_32

for the RFC 2960 Appendix B algorithm. To set this value, SCTP must have been compiled with ‘CONFIG_SCTP_ADLER_32’ or without ‘CONFIG_SCTP_CRC_32C’. When computed in software, Adler 32 checksum algorithm is more amenable to Van Jacobson partial checksum and copy from user approaches and exhibits higher performance than CRC-32c.

SCTP_CSUM_CRC_32C

for the RFC 3309 CRC-32c checksum algorithm. To set this value, SCTP must have been compiled with ‘CONFIG_SCTP_CRC_32C’. When computed in software, CRC-32c checksum is more processor intensive than Adler-32.

As RFC 3309 has been approved and replaces RFC 2960 checksum algorithm, the default value for this system control is now ‘SCTP_CSUM_CRC_32C’. This value may also be set for a given socket using the ‘SCTP_CKSUM_TYPE’ socket option as described in SOCKET OPTIONS. This system control will soon be deprecated, should always be set to ‘SCTP_CSUM_CRC_32C’ and should not be used by portable programs.

sctp_mac_type

Defines the default MAC (Message Authentication Code) type that will be used when signing cookies in INIT-ACK messages. Valid values are:

SCTP_HMAC_SHA_1

for the FIPS 180-1 Secure Hash Algorithm SHA-1 HMAC. SHA-1 performs well on big-endian machines. This option setting is only supported if SCTP was compiled with the kernel configuration parameter ‘CONFIG_SCTP_HMAC_SHA1’ set.

SCTP_HMAC_MD5

for the RFC 1321 Message Digest 5 HMAC. MD5 performs well on little-endian machines. This option setting is only supported if SCTP was compiled with the kernel configuration parameter ‘CONFIG_SCTP_HMAC_MD5’ set.

SCTP_HMAC_NONE

for no secure signature. Not signing the cookie performs well on all machines; however, this option should only be used if some other mechanism provides security (such as IPSec) or the system is closed and trusted. This option setting is always supported.

There is no required or recommended value in RFC 2960. The default value is (in priority of availability) ‘SCTP_HMAC_MD5’, ‘SCTP_HMAC_SHA_1’, then ‘SCTP_HMAC_NONE’. This system control defines the default for new sockets. The MAC for a given socket can be changed before the call to listen(2), or before receiving a passive connection attempt, with the socket option ‘SCTP_MAC_TYPE’ as described under SOCKET OPTIONS.

sctp_valid_cookie_life

Defines the default time interval (in milliseconds) in conjunction with sctp_cookie_inc beyond which a COOKIE-ECHO received with a cookie sent in a INIT-ACK will not longer be accepted. For SCTP, this also limits the default maximum time interval for which the HMAC secret key for the cookie will be valid. Valid values are zero (0) or greater (INT_MAX). Values of zero (0) will be converted to a Linux system clock tick (1000/HZ milliseconds). The default value is the value recommended in RFC 2960 (60,000 milliseconds). This system control defines the default for new sockets. The value for a given socket can be changed with the socket option ‘SCTP_COOKIE_LIFE’ before a call to listen(2), or before receiving passive connection attempt, as described under SOCKET OPTIONS.

Reducing this value will increase the chances that passive connection attempts will fail due to expired cookies. Increasing the value will reduce the overall security of the system by permitting attackers and increased interval to crack HMACs and guess verification tags. This value may be adjusted in conjunction with sctp_cookie_inc to meet most objectives for successful passive connection attempts with the best security afforded by smaller values of sctp_valid_cookie_life.

Unfortunately the ‘SCTP_COOKIE_LIFE’ and ‘SCTP_COOKIE_INC’ must be adjusted to accommodate the slowest peer on the slowest connection. The default setting is adequate for Internet applications.

sctp_cookie_inc

Defines the default time increment (in milliseconds) that will be added to the lifespan of the cookie in an INIT ACK if the received INIT requests cookie preservative to lengthen the lifespan of the cookie. Valid values are zero (0) or greater (INT_MAX). The default value is the value recommended in RFC 2960 5.2.6 (1,000 milliseconds). This system control defines the default for new sockets. The cookie lifetime increment for a given socket can be changed before a call to listen(2), or before receiving a passive connection attempt, with the socket option ‘SCTP_COOKIE_INC’ as described under SOCKET OPTIONS.

This value can be adjusted in conjunction with sctp_valid_cookie_life, above, to meet objectives of successful passive connection attempts and security. The default setting is adequate for Internet applications.

sctp_throttle_itvl

Defines the default time interval (in milliseconds) within which the receiver will not accept more than one INIT or COOKIE ECHO. Zero (don't throttle) is a valid value. The default value is 50 milliseconds. This system control defines the default for new sockets. The throttle interval for a given socket can be changed before the call to listen(2), or before a passive connection attempt, with the socket option ‘SCTP_THROTTLE_ITVL’ as described under SOCKET OPTIONS.

When the HMAC type is SHA-1 or MD5, and when CRC-32c software checksum is used, the implementation is particularly vulnerable to DoS flood attacks using bogus INIT or COOKIE ECHO messages. When SCTP is compiled with ‘CONFIG_SCTP_THROTTLE_PASSIVEOPENS’, this permits the throttling of INIT and COOKIE ECHO messages. Only one INIT and one COOKIE ECHO message will be accepted in the interval set by this control.

sctp_max_istreams

Defines the default maximum number of inbound streams that will be requested when forming or receiving connections on a socket. Valid values are in the range from 1 to 65,535 streams. This system control defines the default for new sockets. The actual value used by a socket for both outgoing and incoming connections can be changed with the socket option ‘SCTP_ISTREAMS’ before a call to connect(2) or accept(2) as described under SOCKET OPTIONS.

Usable default values for sctp_max_istreams are highly dependent upon the intended applications. SIGTRAN UAs, for example, seldom need more than 257 inbound or outbound streams. The default valid is set to thirty-three (33) streams for ‘SOCK_SEQPACKET’ sockets. This system control only affects ‘SOCK_SEQPACKET’ sockets: ‘SOCK_STREAM’ sockets always have both inbound and outbound streams set to one (1).

sctp_req_ostreams

Defines the default requested number of outbound streams that will be requested when forming or receiving connections on a socket. Valid values are in the range from 1 to 65,535 streams. This system control defines the default for new sockets. The actual value used by a socket for both outgoing and incoming connections can be changed with socket option ‘SCTP_OSTREAMS’ before a call to connect(2) or accept(2) as described under SOCKET OPTIONS.

Usable default values for sctp_max_istreams are highly dependent upon the intended applications. SIGTRAN UAs, for example, seldom need more than 257 inbound or outbound streams. The default valid is set to one (1) streams for ‘SOCK_SEQPACKET’ sockets. This system control only affects ‘SOCK_SEQPACKET’ sockets: ‘SOCK_STREAM’ sockets always have both inbound and outbound streams set to one (1).

sctp_ecn

Defines a default flag that allows disabling of Explicit Congestion Notification (ECN) operation for SCTP when cleared. This system control defines the default for new sockets. ECN can be overridden on a per-socket basis with the socket option ‘SCTP_ECN’, as described under SOCKET OPTIONS. For this system control to have any effect, the kernel must have been compiled with both kernel configuration parameters ‘CONFIG_INET_ECN’ and ‘CONFIG_SCTP_ECN’ set.

sctp_adaptation_layer_info

Defines the default adaptation layer information flags that will be sent in an INIT or INIT-ACK message. Valid values include any 32-bit unsigned integer. The default value for backward compatibility is zero (0) which indicates to not send the Adaptation Layer Information parameter in INIT and INIT-ACK. This system control defines the default for new sockets. The actual value for both outgoing and incoming connections can be changed with socket option ‘SCTP_ALI’ before a call to connect(2) or listen(2), or before a passive connection indication on a listening socket, as described under SOCKET OPTIONS. For this system control to have any effect, the kernel must have been compiled with kernel configuration parameter ‘CONFIG_SCTP_ADAPTATION_LEVEL_INFO’ set.

sctp_partial_reliability

Defines the default partial reliability preference that will be used for the socket. Valid values include zero (0) \- no partial reliability reported, one (1) partial reliability support preferred but not required, and two (2), partial reliability support required. The default value for backward compatibility is zero (0). This system control defines the default for new sockets. The actual value for both outgoing and incoming connections can be changed with socket option ‘SCTP_PR’ before a call to connect(2) or listen(2), or before a passive connection indication on a listening socket, as described under SOCKET OPTIONS. For this system control to have any effect, the kernel must have been compiled with kernel configuration parameter ‘CONFIG_SCTP_PARTIAL_RELIABILITY’ set.

sctp_wmem

Defines three values (lower, default, upper) for the socket write buffer. The value associated with a given socket can also be changed with the ‘SO_SNDBUF’ option, see socket(7).

sctp_rmem

Defines three values (lower, default, upper) for the socket read buffer. The value associated with a given socket can also be changed with the ‘SO_RCVBUF’ option, see socket(7).

sctp_max_init_retries

Defines the default number of times that an INIT or COOKIE-ECHO will be resent to a given destination before abandoning an active open attempt. Valid values are zero (0) or greater (INT_MAX). The default value is the value recommended in RFC 2960 (8 retries). This system control defines the default for new sockets. The value for a given socket can be changed with the socket option ‘SCTP_MAX_INIT_RETRIES’ as described under SOCKET OPTIONS.

sctp_max_burst

Defines the default maximum number of MTUs of new data chunks that will be sent in a burst in accordance with <rfc4460.txt>. Valid values are one (1) or greater (INT_MAX). The default value is the value recommended in <rfc4460.txt> (4 MTUs). This system control defines the default for new sockets. The value for a given socket can be changed with the socket option ‘SCTP_MAX_BURST’ as described under SOCKET OPTIONS.

sctp_assoc_max_retrans

Defines the number of times that the sending endpoint will attempt retransmitting a packet on any active destination transport address before it aborts the association. Valid values are zero (0) or greater (INT_MAX). The default value is the value recommended in RFC 2960 (10 retries). This system control defines the default for new sockets. The value for a given socket can be changed with the socket option ‘SCTP_ASSOC_MAX_RETRANS’ as described under SOCKET OPTIONS.

This value should be larger than the sum of the sctp_path_max_retrans values of each of the destinations. Setting this value to less that sum of the sctp_path_max_retrans values for all of the destinations has the interesting effect of permitting a connection to persist even when all destinations have been deemed inactive.

sctp_max_sack_delay

Defines the default interval of time (in milliseconds) that the sending endpoint is permitted to delay an acknowledgement of received data. Valid values are in the range from zero (0) to 500 milliseconds. (RFC 2960 forbids setting this value larger than 500 milliseconds.) The default value is the value recommended in RFC 2960 (200 milliseconds). This system control defines the default for new sockets. The value for a given socket can be changed with the socket option ‘SCTP_SACK_DELAY’ as described under SOCKET OPTIONS.

sctp_rto_min

Defines the default time interval (in milliseconds) that will be used as a RTO (Retransmission Time Out) value when sending packets to a destination transport address. Valid values are zero (0) or greater (INT_MAX) and must be less than or equal to both sctp_rto_initial and sctp_rto_max. The default value is the value recommended in RFC 2960 (1,000 milliseconds). The actual value used can be changed with the socket option ‘SCTP_RTO_MIN’ before a call to connect(2) or accept(2) or before a new destination transport address is added by the peer. After a socket is connected or a destination transport address has been added, the destination-specific value can be changed using the socket option ‘SCTP_RTO’ as described under SOCKET OPTIONS.

In general, sctp_rto_min should not be less than the peer's sctp_max_sack_delay. Otherwise, excessive retransmissions might occur while the peer is delaying acknowledgements.

sctp_rto_initial

Defines the default time interval (in milliseconds) that will be used as an initial RTO (Retransmission Time Out) value when sending packets to a destination for the first time, or after the destination has been idle for some time. Valid values are zero (0) or greater (INT_MAX) and must be in the range from sctp_rto_min to sctp_rto_max. The default value is the value recommended in RFC 2960 (3,000 milliseconds). This system control defines the default for new sockets. The actual value used can be changed with the socket option ‘SCTP_RTO_INITIAL’ before a call to connect(2) or accept(2) or before a new destination transport address is added by the peer. After a socket is connected or a destination transport address has been added, the destination-specific value can be changed using the socket option ‘SCTP_RTO’ as described under SOCKET OPTIONS.

In general, sctp_rto_initial should not be less than the peer's sctp_max_sack_delay. Otherwise, excessive retransmissions might occur while the peer is delaying acknowledgements.

sctp_rto_max

Defines the default time interval (in milliseconds) that will be used as a maximum RTO (Retransmission Time Out) value when sending packets to a destination. Valid values are zero (0) or greater (INT_MAX) and must be greater than or equal to both sctp_rto_min and sctp_rto_initial. The default value is the value recommended in RFC 2960 (60,000 milliseconds). This system control defines the default maximum for new sockets. The actual value used can be changed with the socket option ‘SCTP_RTO_MAX’ before a call to connect(2) or accept(2) or before a new destination transport address is added by the peer. After an socket is connected or a destination transport address has been added, the destination-specific value can be changed using the socket option ‘SCTP_RTO’ as described under SOCKET OPTIONS.

In general, sctp_rto_initial should not be less than the peer's sctp_max_sack_delay. Otherwise, excessive retransmissions might occur while the peer is delaying acknowledgements.

sctp_path_max_retrans

Defines the default number of times that SCTP will attempt retransmitting a packet on to a given destination transport address before it considers that destination transport address inactive. Valid values are zero (0) or greater (INT_MAX). The default value is the value recommended in RFC 2960 (5 retries). This system control defines the default maximum for new sockets. The actual value used can be changed with the socket option ‘SCTP_PATH_MAX_RETRANS’ before a call to connect(2) or accept(2) or before a new destination transport address is added by the peer. After a socket is connected or a destination transport address has been added, the destination-specific value can be changed using the socket option ‘SCTP_RTO’ as described under SOCKET OPTIONS.

Adjusting this value has an effect on the period of time taken to fail-over between destinations for multi-homed connections. Lower values (including zero) will yield faster fail-over response times. Lower values, however, may cause thrashing between destinations contributing to congestion in the network. Default values are applicable to Internet applications.

sctp_heartbeat_itvl

Defines the default interval (in seconds) between successive HEARTBEAT messages used to probe destination transport address for RTT calculation and activity. Valid values are 1 second or greater. The default value is the value recommended in RFC 2960 (30 seconds). This system control defines the default for new sockets. The actual value used can be changed with the socket option ‘SCTP_HEARTBEAT_ITVL’ before a call to connect(2) or accept(2) or before a new destination transport address is added by the peer. After a socket is connected or a destination transport address has been added, the destination-specific value can be changed using the socket option ‘SCTP_HB’ as described under SOCKET OPTIONS.

If the kernel configuration parameter ‘CONFIG_SCTP_THROTTLE_HEARTBEATS’ is set, then half this value is also used for throttling heartbeats. Then only two heartbeats per interval are permitted, any additional heartbeats are discarded.

SOCKET OPTIONS

To set or get a socket option, call getsockopt(2) to read or setsockopt(2) to write the option with the socket level argument set to ‘SOL_SCTP’. In addition, most ‘SOL_SOCKET’ and ‘SOL_IP’ socket options are valid on SCTP sockets. For more information see socket(7) and ip(7).

The following ‘SOL_SOCKET’ socket(7) socket options are supported by SCTP:

SO_KEEPALIVE

Set or get a flag that controls heartbeats for the entire association. See socket(7) for additional information.

Normally SCTP is required to send HEARTBEAT chunks on a per-destination basis. Clearing this flag (setting ‘SO_KEEPALIVE’ to zero) disables exchanging heartbeats on an association level. Exchanging heartbeats is an essential part of the Stream Control Transmission Protocol (SCTP). It is required for clearing retransmission counts against destinations that otherwise will not be cleared if no data is sent and acknowledged to that destination. Disabling heartbeats is provided for in the SCTP specifications (RFC 2960); however, disabling heartbeats is not recommended. This is in contrast to tcp(7) that only rarely heartbeats and for which heartbeats are neither an essential nor necessary part of the protocol.

Heartbeats can also be enabled or disabled on a destination basis using the ‘SCTP_HB’ socket option. It is also possible to generate a HEARTBEAT under user control by sending heartbeat data with the ‘MSG_PROBE’ flag set using send(2), sendto(2) or sendmsg(2).

SO_OOBINLINE

If this option is enabled, out of order data that has been received on a stream will be placed between the ordered data for that stream. Otherwise, out of order data is only returned on a read call when the ‘MSG_OOB’ flag is set when receiving. This option is ignored for ‘SOCK_RDM’ sockets and only applies to ‘SOCK_STREAM’ and ‘SOCK_SEQPACKET’ sockets. See socket(7) for additional information.

SO_BINDTODEVICE

Binds the socket to a particular device. This is not yet supported for SCTP; however, support for it is planned for the future. See socket(7) for additional information.

SO_REUSEADDR

Supported by SCTP without modification; however, consideration is made for binding of multiple transport addresses. See socket(7) for additional information.

SO_RCVLOWAT

SO_SNDLOWAT

SO_RCVTIMEO

SO_SNDTIMEO

SO_DEBUG

SO_TYPE

SO_DONTROUTE

SO_SNDBUF

SO_RCVBUF

SO_LINGER

SO_PRIORITY

SO_ERROR

These socket options are supported by SCTP without modification. See socket(7) for additional information.

The following ‘SOL_IP’ ip(7) socket options are supported by SCTP:

IP_OPTIONS

Set or get the IP options to be sent with every packet from this socket. See ip(7) for additional information.

IP_PKTINFO

Pass an ‘IP_PKINFO’ ancillary message that contains the pktinfo structure that supplies some information about the incoming or outgoing packet. This only works for ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets. It is ignored for ‘SOCK_STREAM’ sockets. For setsockopt(2) and getsockopt(2), the argument is a flag that tells the socket whether the ‘IP_PKTINFO’ message should be passed or not. The message itself can only be sent or retrieved as a control message with a packet using recvmsg(2) or sendmsg(2).

          struct in_pktinfo {
              unsigned int    ipi_ifindex;    /* Interface index      */
              struct in_addr  ipi_spec_dst;   /* Local address        */
              struct in_addr  ipi_addr;       /* Header Dest Address  */
          };

‘ipi_ifindex’

is the unique index of the interface the packet was received on, or the index of the interface upon which the packet is to be sent;

‘ipi_spec_dst’

is the local address of the received packet or sent packet, and

‘ipi_addr’

is the destination address in the packet header.

If ‘IP_PKTINFO’ is passed to sendmsg(2) then the outgoing packet will be sent over the interface specified in ipi_ifindex with the destination address set to ipi_spec_dst.

This option is used to control the source (local) address of packets sent with sendmsg(2) and to retrieve the destination (local) address of packets received with recvmsg(2). See ip(7) for additional information.

Support for ‘IP_PKTINFO’ is similar to support for this socket option under udp(7). Under udp(7), ‘IP_PKTINFO’ is used for multi-homed UDP hosts to specify the local address to sendmsg(2) and return remote address from recvmsg(2). SCTP uses this in a similar fashion where the choice of addresses consists of the address space of the association.

IP_RECVTOS

Set or get the flag indicating whether the recvmsg(2) call will return the type of service field for the received packet in an ancillary message as a ‘IP_TOS’ control message for sockets of type ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’. This option is ignored for ‘SOCK_STREAM’ sockets. See ip(7) for additional information.

IP_RECVTTL

Set or get the flag indicating whether the recvmsg(2) call will return the time to live field for the received packet in an ancillary message as a ‘IP_TTL’ control message for sockets of type ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’. This option is ignored for ‘SOCK_STREAM’ sockets. See ip(7) for additional information.

IP_RECVOPTS

Set or get the flag indicating whether the recvmsg(2) call will return the IP options for the received packet in an ancillary message as an ‘IP_OPTIONS’ control message for sockets of type ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’. This option is ignored for ‘SOCK_STREAM’ sockets. See ip(7) for additional information.

IP_RETOPTS

Set or get the flag indicating whether the recvmsg(2) call will return the IP options for the received packet in an ancillary message as an ‘IP_RETOPTS’ control message for sockets of type ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’. This option is ignored for ‘SOCK_STREAM’ sockets. See ip(7) for additional information.

In contrast to ‘IP_OPTIONS’, the ‘IP_RETOPTS’ ancillary message contains raw, unprocessed options, with the time stamp and route record options not filled in for this hop. It is also possible to pass an ‘IP_RETOPTS’ ancillary message to sendmsg(2).

IP_TOS

Set or get the default type of service to be used in IP packets associated with the connection. For ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets, this option can also be passed to sendmsg(2) in the ancillary data and will be used as the type of service field in the IP packet containing the data chunk associated with the user data provided in the call to sendmsg(2). For ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets, this option returns the type of service parameter associated with a packet in the ancillary data returned from a call to recvmsg(2) when the ‘IP_RECVTOS’ option has been set on the socket. This option is ignored for ‘SOCK_STREAM’ sockets. See ip(7) for additional information.

IP_TTL

Set or get the default time to live to be used in IP packets associated with the connection. This option can also be passed to sendmsg(2) in the ancillary data and will be used as the time to live field in the IP packet containing the data chunk associated with the user data provided in the call to sendmsg(2). See ip(7) for additional information.

IP_MTU

For SCTP sockets, this returns only the Path MTU for the association. This value is the minimum MTU of all the peer destinations. See SCTP socket options for a mechanism for obtaining MTU on a per-destination basis. When the peer is not multi-homed, this option returns the same value as would be obtained on a per-destination basis. See ip(7) for additional information.

IP_RECVERR

For SCTP sockets, this enables extended reliable error messages with the use of ‘SO_ERROR’ as for tcp(7). Error queues are not supported for SCTP (they are not supported for tcp(7) either). As for tcp(7), SCTP does not permit calling recvmsg(2) with the ‘MSG_ERRQUEUE’ flag for ‘SOCK_SEQPACKET’ and ‘SOCK_STREAM’ sockets.

IP_PMTU_DISCOVER

Supported for SCTP sockets without modification. See ip(7) for additional information.

The following ‘SOL_SCTP’ socket options are supported: (A number of the following socket options may also be passed as an ancillary message with level ‘SOL_SCTP’ when calling sendmsg(2) or returned as a control message from a call to recvmsg(2).)

SCTP_NODELAY

Turn the Nagle algorithm off. This means that packets are always sent as soon as possible and no unnecessary delays are introduced, at the cost of more packets in the network. Expects an integer boolean flag.

This parallels the ‘TCP_NODELAY’ socket option for compatibility with tcp(7). ‘SCTP_NODELAY’ and ‘TCP_NODELAY’ can be used interchangeably. For ‘SOCK_STREAM’ sockets, this setting applies to the default stream as set by the ‘SCTP_SID’ socket option. For regular ‘SOCK_SEQPACKET’ sockets, this setting applies to the entire association. For ‘SOCK_STREAM’ sockets, this setting has the same effect as tcp(7). This option has no effect on ‘SOCK_RDM’ sockets. See tcp(7) for additional information.

When Nagle is enabled, SCTP uses the Nagle algorithm (RFC 896) for bundling DATA chunks into a packet. This results in far fewer short packets in the network. The algorithm is that described in RFC 896 and RFC 1122 with the Minshall modifications to accommodate delayed SACK as described in <draft-minshall-tsvwg-nagle-01.txt>. (Note: later versions of tcp(7) also in include the Minshall modification).

SCTP_MAXSEG

Set or get the maximum segment size for outgoing packets. Values greater than the association MTU are ignored and have no effect.

This parallels the ‘TCP_MAXSEG’ socket option for compatibility with tcp(7). ‘SCTP_MAXSEG’ and ‘TCP_MAXSEG’ can be used interchangeably. This option is applicable to both ‘SOCK_SEQPACKET’ and ‘SOCK_STREAM’ sockets.

This value determines the maximum size (in bytes) above which SCTP will fragment larger DATA chunks into smaller DATA chunks, and beneath which SCTP will bundle DATA chunks into a single packet or combine smaller DATA chunks into larger DATA chunks. Normally this value is the association MTU value minus the size of the current IP and SCTP headers, minus the size of one DATA chunk header. If the user sets this to a lower value, the lower value will be used.

SCTP_CORK

If enabled don't send out partial frames. All queued partial frames are sent when the option is cleared again. This is useful for prefixing headers before calling sendfile(2), or for throughput optimization. This option cannot be combined with ‘SCTP_NODELAY’.

This parallels the ‘TCP_CORK’ socket option for compatibility with tcp(7). ‘SCTP_CORK’ and ‘TCP_CORK’ can be used interchangeably. For ‘SOCK_STREAM’ sockets, this setting applies to the default stream as set by the ‘SCTP_SIB’ socket option. For regular ‘SOCK_SEQPACKET’ sockets, this setting applies to the entire association. This option has no effect on ‘SOCK_RDM’ sockets.

SCTP_SID

Set or get the default stream identifier for all outgoing packets associated with the connection. If ‘SCTP_SID’ is passed to sendmsg(2) then the outgoing packet will be sent over the stream specified by the integer stream identifier contained in the ancillary message. If ‘SCTP_SID’ is received from a call to recvmsg(2) then the incoming packet was received over the stream specified by the integer stream identifier contained in the ancillary message. See also ‘SCTP_RECVSID’.

SCTP_PPI

Set or get the default payload protocol identifier for all outgoing packets. If ‘SCTP_PPI’ is passed to sendmsg(2) then the outgoing packet will be sent with the payload protocol identifier specified by the integer payload protocol identifier contains in the ancillary message. If ‘SCTP_PPI’ is received from a call to recvmsg(2) then the incoming packet was received with the payload protocol identifier specified the integer payload protocol identifier contained in the ancillary message. See also ‘SCTP_RECVPPI’.

SCTP_RECVSID

When this flag is set, pass a ‘SCTP_SID’ control message with the stream identifier for received packets as an integer in an ancillary message that may be received with recvmsg(2). Otherwise, no ‘SCTP_SID’ control message will be passed with normal data. ‘SCTP_SID’ is always passed for retrieved or negatively acknowledged data.

SCTP_RECVPPI

When this flag is set, pass a ‘SCTP_PPI’ control message with the payload protocol identifier for received packets as an integer in an ancillary message that may be received with recvmsg(2). Otherwise, no ‘SCTP_PPI’ control message will be passed with normal data. ‘SCTP_PPI’ is always passed for retrieved or negatively acknowledged data.

SCTP_HEARTBEAT_ITVL

Set or get the time interval (in seconds) between successive HEARTBEAT messages used to probe destination transport addresses for RTT calculation and activity. Valid values are zero (0) \- do not heartbeat, or a value of 1 second or greater. The default value is set by the system control sctp_heartbeat_itvl. This is the default value that will be assigned to new destinations. Active destinations can be controlled with the socket option ‘SCTP_HB’. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection indication is received on a listening socket.

SCTP_HB

Set or get the heartbeat activation and interval associated with the specified destination address. The expected value is a sctp_hbitvl structure. This option will return an error if it is attempted on a socket in the unconnected state.

          struct sctp_hbitvl {
              struct sockaddr_in
                    dest;   /* destination address      */
              uint  active; /* activation flag          */
              uint  itvl;   /* interval in milliseconds */
          };

The sctp_hbitvl structure has the following fields:

‘dest’

is a sockaddr_in structure that contains the destination address to which the heartbeat setting applies.

‘active’

is an integer boolean activation flag indicating whether heartbeat is active on the destination.

‘itvl’

is the integer heartbeat interval in milliseconds.

For use with setsockopt(2), dest must be one of the valid destination addresses associated with the connection: that is, it must be one of the addresses returned from a call to getpeername(2). Note that heartbeat activity and interval can also be set on an association basis with ‘SO_KEEPALIVE’ and ‘SCTP_HEARTBEAT_ITVL’.

SCTP_RTO_INITIAL

Set or get the time interval (in milliseconds) that will be used as an initial RTO (Retransmission Time Out) value when sending packets to a destination for the first time. Valid values are zero or greater and must be within the range from ‘SCTP_RTO_MIN’ to ‘SCTP_RTO_MAX’. The default value is the value set by sctp_rto_initial. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection attempt, but the value may be controlled on active destination with the ‘SCTP_RTO’ socket option.

SCTP_RTO_MIN

Set or get the time interval (in milliseconds) that will be used as a minimum RTO (Retransmission Time Out) value when sending packets. Valid values are zero or greater and must be less than or equal to the value of ‘SCTP_RTO_MAX’. The default value is set by the system control sctp_rto_min. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection attempt, but the value associated with active destinations can be controlled using the ‘SCTP_RTO’ socket option.

SCTP_RTO_MAX

Set or get the time interval (in milliseconds) that will be used as a maximum RTO (Retransmission Time Out) value when sending packets. Valid values are zero or greater and must be greater than or equal to the value of ‘SCTP_RTO_MIN’. The default value is set by the system control sctp_rto_max. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection attempt, but the value associated with active destinations can be controlled using the ‘SCTP_RTO’ socket option.

SCTP_PATH_MAX_RETRANS

Set or get the number of times that the sending endpoint will attempt retransmitting a packet to a given destination transport address before it considers that destination transport address inactive. Valid values include zero. The default values is set by the system control sctp_path_max_retrans. This is the default value assigned to destinations before the call to connect(2) or listen(2), or before a passive connection attempt. Active destinations can be controlled with the ‘SCTP_RTO’ socket option.

SCTP_RTO

Set or get the retransmission timeout parameters associated with the specified destination address. The expected value is a sctp_rtoval structure. This option will return an error if it is attempted on a socket in the unconnected state.

          struct sctp_rtoval {
              struct sockaddr_in
                    dest;        /* destination address        */
              uint  rto_initial; /* RTO.Initial (milliseconds) */
              uint  rto_min;     /* RTO.Min     (milliseconds) */
              uint  rto_max;     /* RTO.Max     (milliseconds) */
              uint  max_retrans; /* Path.Max.Retrans (retries) */
          };

The sctp_rtoval structure has the following fields:

‘dest’

is a sockaddr_in structure that contains the destination address to which the RTO parameter setting applies.

‘rto_initial’

is the integer initial retransmission timeout value in milliseconds. For expected values see ‘SCTP_RTO_INITIAL’.

‘rto_min’

is the integer minimum retransmission timeout value in milliseconds. For expected values see ‘SCTP_RTO_MIN’.

‘rto_max’

is the integer maximum retransmission timeout value in milliseconds. For expected values see ‘SCTP_RTO_MAX’.

‘max_retrans’

is the integer maximum number of retransmissions. For expected values see ‘SCTP_PATH_MAX_RETRANS’.

For use with setsockopt(2), dest must be one of the valid destination addresses associated with the connection: that is, it must be one of the addresses returned from a call to getpeername(2).

SCTP_CKSUM_TYPE

Set or get the checksum algorithm associated with socket. Valid values are ‘SCTP_CSUM_ADLER_32’ and ‘SCTP_CSUM_CRC_32C’. The default value is set by the system control sctp_csum_type. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection attempt on a listening socket.

SCTP_MAC_TYPE

Set or get the MAC (Message Authentication Code) type that will be used when signing cookies in INIT ACK messages. Valid values are ‘SCTP_HMAC_SHA_1’, ‘SCTP_HMAC_MD5’, and ‘SCTP_HMAC_NONE’. The default value is set by the system control sctp_mac_type. This socket option must be set before the call to listen(2), or before a passive connection attempt on a listening socket.

SCTP_COOKIE_LIFE

Set or get the cookie lifetime associated with a socket. This is the amount of time that cookies sent to a peer endpoint in an INIT-ACK message will be valid. For SCTP this also limits the maximum for which the HMAC secret key for the cookie will be valid. The value is a integer time interval in milliseconds. Valid values are zero (0) or greater (INT_MAX). The default value is set by the system control sctp_cookie_life. This socket option must be set before the call to listen(2), or before receiving a passive connection attempt. When changing this value, the new value will apply to all passive connection attempts (INIT messages) received on a listening socket after the change is made.

Reducing this value will increase the chances that passive connection attempts will fail due to expired cookies. Increasing the value will reduce the overall security of the system by permitting attackers and increased interval to crack HMACs and guess verification tags. This value may be adjusted in conjunction with ‘SCTP_COOKIE_INC’ to meet most objectives for successful passive connection attempts with the best security afforded by smaller values of ‘SCTP_COOKIE_LIFE’.

Unfortunately the ‘SCTP_COOKIE_LIFE’ and ‘SCTP_COOKIE_INC’ must be adjusted to accommodate the slowest peer on the slowest connection. The default setting is adequate for Internet applications.

SCTP_COOKIE_INC

Set or get the time increment (in milliseconds) that will be added to the lifespan of the cookie in an INIT ACK if the sender of the INIT requested cookie preservation to lengthen the lifespan of the cookie. Valid values include zero. The default value is set by the system control sctp_cookie_inc. This socket option must be set before the call to listen(2), or before a passive connection attempt on the listening socket, but can be read at any time.

SCTP_THROTTLE_ITVL

Set or get the interval (in milliseconds) within which the receiver will not accept more than one INIT or COOKIE ECHO. Zero (don't throttle) is a valid value. The default is set by the system control sctp_throttle_itvl. This socket option must be set before the call to listen(2), or before a passive connection attempt on the listening socket.

SCTP_ISTREAMS

Set the maximum number of inbound streams or get the actual number of inbound streams associated with a connection. Valid values are from 1 to 16,736. The default value is set by the system control sctp_max_istreams. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection attempt, but can be read at any time. For tcp(7)-compatible ‘SOCK_STREAM’ sockets, the number of inbound streams is fixed at one (1) and this socket option has no effect.

SCTP_OSTREAMS

Set the number of requested outbound streams or get the actual number of outbound streams associated with a connection. Valid values are from 1 to 16,736. The default value is set by the system control sctp_req_ostreams. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection attempt on a listening socket, but can be read at any time. For tcp(7)-compatible ‘SOCK_STREAM’ sockets, the number of outbound streams is fixed at one (1) and this socket option has no effect.

SCTP_ECN

When set to zero (0), disables the local transport Explicit Congestion Notification (ECN) capability, or get the transport ECN capability of the peer on a connected socket.

This socket option supports the ECN capability of RFC 3168 and Appendix A of RFC 2960 and is only available if SCTP was compiled with the kernel configuration parameters ‘CONFIG_INET_ECN’ and ‘CONFIG_SCTP_ECN’ set.

SCTP_ALI

Set the adaptation layer information to be used in the INIT or INIT-ACK on all passive or active connection attempts on the socket, or get the adaptation layer information provided by the peer on a connected socket.

When set to zero (0), no adaptation layer information will be included in the INIT or INIT-ACK; when non-zero, it contains the flag bits that will be sent in the adaptation layer information in the INIT or INIT-ACK when set before the call to connect(2) or listen(2), or before a passive connection information is received on a listening socket.

If the socket is in a disconnected state (and has never been connected), getting this option returns zero (0). If the socket has been in a connected state, getting this option returns zero (0) if no adaptation layer information was present during connection, or returns the adaptation layer information bits if provided by the peer.

This socket option supports the adaptation layer information feature described in <draft-ietf-tsvwg-addip-sctp-08.txt> and is only supported if SCTP was compiled with kernel configuration parameter ‘CONFIG_SCTP_ADAPTATION_LAYER_INFO’ set.

SCTP_PR

Set whether Partial Reliability (RFC 3758) will be supported or required on connection establishment, or get the indication of support for PR-SCTP provided by the peer on a connected socket. Valid values are as follows:

SCTP_PR_NONE

Do not place or respond with Forward TSN parameter in an INIT or INIT-ACK indicating that this socket does not support PR-SCTP.

SCTP_PR_PREFERRED

Place and respond with a Forward TSN parameter in an INIT or INIT-ACK indicating to the peer that we support PR-SCTP for this connection, but do not require the peer to support PR-SCTP.

SCTP_PR_REQUIRED

Place and respond with a Forward TSN parameter in an INIT or INIT-ACK indicating to the peer that we support PR-SCTP and require the peer to do the same.

The default setting is provided by the sctp_pr system control.

For a connected socket, when this flag is true, it indicates that the peer supports PR-SCTP. When this flag is false, it indicates that the peer does not support PR-SCTP.

This socket options supports the partial reliability feature (RFC 3758) and is only available if SCTP was compiled with the kernel configuration parameter ‘CONFIG_SCTP_PARTIAL_RELIABILITY’ set.

SCTP_MAX_INIT_RETRIES

Set or get the number of times that an INIT or COOKIE ECHO will be resent before abandoning the association initialization. Valid values include zero. The default value is set by the system control sctp_max_init_retries. This socket option must be set before the call to connect(2) or listen(2), or before a passive connection attempt on a listening socket.

SCTP_MAX_BURST

Set or get the number of MTUs of data that will be sent in a single burst as defined by <rfc4460.txt>. Valid values are one (1) or greater. The default value is set by the system control sctp_max_burst. This socket option may be changed at any time during the life of the socket.

SCTP_ASSOC_MAX_RETRANS

Set or get the number of times that the sending endpoint will attempt retransmitting a packet on a given association before it aborts the association. Valid values include zero. The default value is set by the system control sctp_assoc_max_retrans. This value should be larger than the sum of all the ‘SCTP_PATH_MAX_RETRANS’ values of each of the destinations. This socket option may be changed at any time during the life of the socket.

SCTP_SACK_DELAY

Set or get the maximum SACK delay as the interval of time (in milliseconds) that the sending endpoint will delay an acknowledgement of a received data chunk. Valid values are in the range from 0 to INT_MAX, however, the value of the maximum SACK delay should not exceed 500 milliseconds (setting this value to greater than 500 milliseconds is forbidden by RFC 2960) for Internet Applications. The default value is set by the system control sctp_sack_delay. This socket option may be changed at any time during the life of the socket.

SCTP_DISPOSITION

Gets or sets a flag that determines whether SCTP will retain and deliver messages that were not successfully acknowledged by the peer for retrieval, or will deliver confirmation of acknowledgement for messages successfully acknowledged by the peer. If ‘SCTP_DISPOSITION’ is return in a control message from a call to recvmsg(2) with the ‘MSG_CONFIRM’ flag set, then the read packet represents a packet that was held for retrieval, exceeded its life-time, was dropped by PR-SCTP or had message confirmation set and was successfully acknowledged. In addition, if the message was successfully acknowledged, the ‘MSG_CONFIRM’ flag will be returned in a call to recv(2), recvfrom(2) or recvmsg(2). Valid values are:

SCTP_DISPOSITION_NONE

When this option is set to ‘SCTP_DISPOSITION_NONE’, messages will not be retained for retrieval and acknowledgements will not be provided for messages unless overridden with the ‘MSG_CONFIRM’ flag to send(2), sendto(2) or sendmsg(2).

SCTP_DISPOSITION_UNSENT

When set to ‘SCTP_DISPOSITION_UNSENT’, SCTP will retain and provide for retrieval only messages that were unsent. When set to ‘SCTP_DISPOSITION_UNSENT’ in an ancillary message returned by recvmsg(2) called with the ‘MSG_CONFIRM’ flag set, the read data represents a packet that was unsent at the time that the connection shut down or aborted. When ‘SCTP_PR’ is enabled on the connection, unsent data that was dropped by PR-SCTP will be delivered before shut down or abort.

SCTP_DISPOSITION_SENT

When set to ‘SCTP_DISPOSITION_SENT’, SCTP will retain and provide for retrieval all messages that were sent and unacknowledged, or that were unsent at the time that the connection shut down or aborted. When set to ‘SCTP_DISPOSITION_SENT’ in an ancillary message returned by recvmsg(2) called with the ‘MSG_CONFIRM’ flag set, then the read data was a packet that was sent but not acknowledged (with a cumulative ack) before the connection was shut down or aborted. When ‘SCTP_PR’ is enabled on the connection, sent data that was dropped by PR-SCTP will be delivered before shut down or abort.

SCTP_DISPOSITION_GAP_ACKED

When set to ‘SCTP_DISPOSITION_GAP_ACKED’, SCTP will retain and provide for retrieval all messages that were sent and gap acknowledged, sent and unacknowledged, or unsent at the time that the connection shut down or aborted. When set to ‘SCTP_DISPOSITION_GAP_ACKED’ in an ancillary message returned by recvmsg(2) called with the ‘MSG_CONFIRM’ flag set, then the read data was a packet that was sent but not acknowledged (with a cumulative ack) before the connection was shut down or aborted. When ‘SCTP_PR’ is enabled on the connection, gap acknowledged data that was dropped by PR-SCTP will be delivered before shut down or abort.

SCTP_DISPOSITION_ACKED

When set to ‘SCTP_DISPOSITION_ACKED’, SCTP will retain and provide for retrieval acknowledgements for all messages that were confirmed delivered (by cumulative ack). When set to ‘SCTP_DISPOSITION_ACKED’ in the ancillary message return by recvmsg(2) called with the ‘MSG_CONFIRM’ flag set, then the read data was a packet that was sent and acknowledged (with a cumulative ack) before the connection was shut down gracefully or at any time before shut down or abort.

This option permits messages that are unsent, sent but not acknowledged or sent and gap acknowledged, to be retrieved from the socket before close. This is accomplished by setting the ‘SCTP_DISPOSITION’ socket option prior to shut down or abort, and then calling recvmsg(2) after ‘POLLHUP’, ‘SIGPIPE’ or ‘EPIPE’ indicating shutdown or abort of the connection. Messages then read with the ‘MSG_CONFIRM’ flag set on call to recv(2), recvfrom(2) or recvmsg(2) will have the ‘SCTP_DISPOSITION’ ancillary message attached and will indicate whether they were ‘SCTP_DISPOSITION_UNSENT’, ‘SCTP_DISPOSITION_SENT’ or ‘SCTP_DISPOSITION_GAP_ACKED’.

If the socket option ‘SCTP_PR’ is set on the socket and the peer supports PR-SCTP, messages which have failed partial reliable delivery (were dropped) will also be retrieved by recvmsg(2) called with the ‘MSG_CONFIRM’ flag set, with the ‘SCTP_DISPOSITION’ ancillary data message before shutdown. SCTP must have been compiled with ‘CONFIG_SCTP_PARTIAL_RELIABILITY’ for this feature to be available.

Alternatively, if the socket option ‘SCTP_DISPOSITION’ is set to ‘SCTP_DISPOSITION_ACKED’ or messages were sent with the ‘MSG_CONFIRM’ flag set to send(2), sendto(2) or sendmsg(2), then a call to recv(2), recvfrom(2) or recvmsg(2) with the ‘MSG_CONFIRM’ flag set will return acknowledgements with a ‘SCTP_DISPOSITION’ control message set to ‘SCTP_DISPOSITION_ACKED’ for all acknowledged messages a the time of the call. Care should be taken when using this receipt confirmation service as the message will be held in the transmit buffers until confirmation has been received by the user. Receipt confirmation also has an impact on the performance of SCTP.

SCTP_LIFETIME

Get or set the SCTP lifetime or PR-SCTP timed reliability lifetime associated with messages which are sent on this socket. When this option is included as an control message to sendmsg(2), the specified lifetime is associated with the written message.

Ordered messages waiting for acknowledgement beyond this lifetime will cause subsequent writes to the same stream to fail until all failed messages have been retrieved with recvmsg(2) with the ‘MSG_CONFIRM’ flag set. Subsequent unordered writes to the stream will succeed, although unordered data can also be collected by setting both ‘MSG_OOB’ and ‘MSG_CONFIRM’ in a call to recvmsg(2).

SCTP_ADD

Sets a flag that indicates whether SCTP will support the ADD-IP extensions (ADD IP and DEL IP) on this socket, or gets a flags that indicates whether the peer supports the ADD-IP extensions on a connected socket. When the flag is set, requests that SCTP respond to ASCONF chunks with ADD IP or DEL IP requests. When the flag is unset, SCTP will refuse these requests. The default setting for this flag is unset for new sockets. This option is only available when the kernel is compiled with kernel configuration parameter ‘CONFIG_SCTP_ADD_IP’ set.

SCTP_ADD_IP

When set, requests that the provided IP address (addr), provided in a sockaddr_in structure be added to the local IP addresses associated with the connection. If the socket is in a connected or connecting state, this invokes the ASCONF procedure to add the IP address to the association. If the socket is in a disconnected state, setting this option will fail. This option is only available when the kernel is compiled with kernel configuration parameter ‘CONFIG_SCTP_ADD_IP’ set.

If a connected socket was initially bound to ‘INADDR_ANY’, additional IP addresses may be automatically added to the socket if new network interfaces are added to the system, or if existing network interfaces are configured with ifconfig(8) or equivalent commands.

SCTP_DEL_IP

When set, requests that the provided IP address (addr), provided in a sockaddr_in structure be deleted from the local IP addresses associated with the connection. If the socket is in a connected or connecting state, this invokes the ASCONF procedure to remove the IP address from the association. If the socket is in a disconnected state, setting this option will fail. This option is only available when the kernel is compiled with kernel configuration parameter ‘CONFIG_SCTP_ADD_IP’ set.

If the socket was initially bound to ‘INADDR_ANY’, IP addresses may be automatically unbound from the socket if network interfaces are removed from the system, or if network interfaces are reconfigured with ifconfig(8) or equivalent commands.

SCTP_SET

Sets a flag that indicates whether SCTP will support the ADD-IP extensions (SET PRIMARY) on this socket, or gets a flags that indicates whether the peer supports the ADD-IP extensions on a connected socket. When the flag is set, requests that SCTP respond to ASCONF chunks with SET PRIMARY requests. When the flag is unset, SCTP will refuse these requests. The default setting for this flag is unset for new sockets. This option is only available when the kernel is compiled with kernel configuration parameter ‘CONFIG_SCTP_ADD_IP’ set.

SCTP_STATUS

Gets the association status and the status associated with each of the destination transport addresses forming the association. The returned value is a sctp_astat structure following by assoc_nrep sctp_dstat structures (one for each destination transport address as returned by getpeername(2)).

          struct sctp_astat {
              uint assoc_rwnd;  /* receive window           */
              uint assoc_rbuf;  /* receive buffer           */
              uint assoc_nrep;  /* destinations reported    */
          };
          
          struct sctp_dstat {
              struct sockaddr_in
                    dest;       /* destination address      */
              uint dst_cwnd;    /* congestion window        */
              uint dst_unack;   /* unacknowledged chunks    */
              uint dst_srtt;    /* smoothed round trip time */
              uint dst_rvar;    /* rtt variance             */
              uint dst_rto;     /* current rto              */
              uint dst_sst;     /* slow start threshold     */
          };

The sctp_astat structure has the following fields:

‘assoc_rwnd’

is the current advertised receive window in bytes.

‘assoc_rbuf’

is the current receive buffer size in bytes.

‘assoc_nrep’

is the number of sctp_dstat structures that follow this structure.

The sctp_dstat structure has the following fields:

‘dest’

is the address associated with this sctp_dstat structure.

‘dst_cwnd’

is the congestion window for the given destination transport address in bytes.

‘dst_unack’

is the number of unacknowledged DATA chunks outstanding to the given destination transport address in chunks.

‘dst_srtt’

is the current smoothed round trip time for the destination transport address in milliseconds.

‘dst_rvar’

is the RTT variance for the destination transport address in milliseconds.

‘dst_rto’

is the current value of the RTO for the destination transport address in milliseconds.

‘dst_sst’

is the current value of the slow start threshold in bytes.

SCTP_DEBUG_OPTIONS

Not Documented. (This socket option provides for special debugging functions intended for developers of SCTP.)

IOCTLS

These I/O controls can be accessed using ioctl(2). The correct syntax is:

     int value;
     error = ioctl(sctp_socket, ioctl_type, &value);

All socket(7) I/O controls are supported by SCTP without modification: ‘SIOCGSTAMP’, ‘SIOCSPGRP’, ‘FIOASYNC’ and ‘SIOCGPGRP’. All socket(7) fcntls are supported by SCTP: ‘FIOCGETOWN’ and ‘FIOCSETOWN’.

The following tcp(7) I/O controls are supported by SCTP:

SIOCINQ

Returns the amount of queued unread data in the receive buffer. Argument is a pointer to an integer.

SIOCATMARK

Returns true when all urgent data has already been received by the user program. This is used together with ‘SO_OOBINLINE’. Argument is a pointer to an integer for the test result.

SIOCOUTQ

Returns the amount of unsent data in the socket send queue in the passed integer value pointer.

ERROR HANDLING

When a network error occurs, SCTP tries to resend the packet. If it doesn't succeed after some time, either ‘ETIMEDOUT’ or the last received error on this connection is reported.

Some applications require a quicker error notification. This can be enabled with the ‘SOL_IP’ level ‘IP_RECVERR’ socket option. When this option is enabled, all incoming errors are immediately passed to the user program. Use this option with care: it makes SCTP less tolerant to routing changes and other normal network conditions.

NOTES

When an error occurs doing a connection setup occurring in a socket write ‘SIGPIPE’ is only raised when the ‘SO_KEEPOPEN’ socket option is set.

SCTP has no real out-of-band or urgent data; it has out-of-order data. In Linux this means if the other end sends newer out-of-band data the older urgent data may arrive later.

If the socket option ‘SO_KEEPALIVE’ is not set (see socket(7)), SCTP will not generate heartbeats to any destination. For regular ‘SOCK_SEQPACKET’ and ‘SOCK_RDM’ sockets, ‘SO_KEEPALIVE’ defaults to set. For tcp(7)-compatible ‘SOCK_STREAM’ sockets, ‘SO_KEEPALIVE’ defaults to unset.

ERRORS

EPIPE

The other end closed the socket unexpectedly or a read is executed on a shut down socket.

ETIMEDOUT

The other end didn't acknowledge retransmitted data after some time.

EAFNOTSUPPORT

Passed socket address type in sin_family was not ‘AF_INET’ or ‘AF_UNSPEC’.

Any errors defined for ip(7) or the generic socket(7) layer may also be returned for SCTP.

NETWORK STATISTICS

Protocol Information

SCTP keeps a number of statistics provided for in the the IP MIB. IP protocol statistics are available in ‘/proc/net/snmp’ as well as with the -s or –statistics flag to netstat(8). For additional information see proc(5) and netstat(8). ICMP Protocol statistics that are applicable to SCTP are as follows:

InErrors

The number of ICMP messages received in error. This represents the value for all protocols including SCTP.

SCTP provides the following information in the Linux MIB. Linux MIB statistics are available in ‘/proc/net/netstat’. For additional information see proc(5). Linux protocol statistics that are applicable also to SCTP are as follows:

LockDroppedIcmps

The number of ICMP errors that were dropped because the socket was locked.

ListenOverflows

The number of COOKIE-ECHO chunks dropped due to listen queue overflows.

SCTP provides for SNMP Protocol Information following the SCTP MIB <rfc3873.txt>. Protocol information is available in ‘/proc/net/snmp’ as well as with the -s flag to the netstat(8) command. SCTP Protocol Statistics that are applicable to SCTP are as follows:

RtoAlgorithm

The algorithm used to determine the timeout value (T3-rtx) used for retransmitting unacknowledged chunks.

RtoMin

The minimum value for the transmission timeout value. This value can be obtained by reading the system control sctp_rto_min. A retransmission time value of zero means immediate retransmission. The value of this object has to be less than or equal to RtoMax's value.

RtoMax

The maximum value for the retransmission timeout value. This value can be obtained by reading the system control sctp_rto_max. A retransmission timeout value of zero means immediate retransmission. The value of this object has to be greater than or equal to RtoMin's value.

RtoInitial

The initial value for the retransmission timer. This value can be obtained by reading the system control sctp_rto_initial. A retransmission time value of zero means immediate retransmission.

MaxAssoc

The maximum number of associations. For SCTP there is no controllable upper limit on the maximum number of associations. The maximum number of associations is constrained by the system maximum number of file descriptors, the process maximum number of file descriptors, and the amount of memory in the system. Therefore, this value will always be -1.

ValCookieLife

The valid cookie life for COOKIEs in the initialization procedure. This value can be obtained by reading the system control sctp_valid_cookie_life.

MaxInitRetr

The maximum number of times that an INIT or COOKIE-ECHO chunk will be retransmitted during the startup of an association. This value can be obtained by reading the system control sctp_max_init_retries.

CurrEstab

The number of SCTP sockets in the established state.

ActiveEstabs

The number of times that a connect(2) call succeeded on an SCTP socket.

PassiveEstabs

The number of times that a accept(2) call succeeded on an SCTP socket.

Aborteds

The number of times that an established SCTP socket completed an abortive release.

Shutdowns

The number of times that an established SCTP socket completed an orderly release.

OutOfBlues

The number of out of the blue packets received. Out of the blue packets are packets for which no corresponding SCTP socket could be found.

ChecksumErrors

The number of received packets that discovered a checksum error and were discarded.

OutCtrlChunks

The number of SCTP Control Chunks that were sent, excluding retransmissions.

OutOrderChunks

The number of SCTP Data Chunks that were sent with the Unordered Bit clear, excluding retransmissions.

OutUnorderChunks

The number of SCTP Data Chunks that were sent with the Unordered Bit set, excluding retransmissions.

InCtrlChunks

The number of SCTP Control Chunks that were received and processed, excluding duplicates.

InOrderChunks

The number of SCTP Data Chunks that were received with the Unordered Bit clear, excluding duplicates.

InUnorderChunks

The number of SCTP Data Chunks that were received with the Unordered Bit set, excluding duplicates.

FragUsrMsgs

The number of times that SCTP further fragmented a user message.

ReasmUserMsgs

The number of times that SCTP reassembled fragmented chunks into a user messages.

OutSCTPPacks

The number of packets delivered for transmission to the IP layer.

InSCTPPacks

The number of packets received for processing from the IP layer.

DiscontinuityTime

The last time at which SCTP statistics suffered a discontinuity.

Connection Information

SCTP provides for SNMP Connection Information following the SCTP MIB <rfc3873.txt>. Connection information is available in ‘/proc/net/sctp’ but is not yet available with a -sctp flag to the netstat(8) command. (Extensions to the netstat(8) command are required to access this information.)

Socket Usage Information

SCTP provides for socket usage information available in ‘/proc/net/sockstat’.

CAVEATS

SCTP does not subscribe to the RFC 2960 restriction to assign sequential TSNs (Transmit Sequence Numbers) to each fragmented DATA chunk of a large record for ‘SOCK_SEQPACKET’ sockets. Multiple calls to write(2), send(2), sendto(2) or sendmsg(2) for portions of different records may result in fragments from multiple records being assigned interleaving TSNs. Portable programs should refrain from writing record fragments to more than one stream at a time.

SCTP ignores the source address list in INIT and INIT-ACK chunks when searching for Transmission Control Blocks in opposition to <rfc4460.txt> section 2.18. This is because the procedure described there introduces severe vulnerability to DoS and Spoofing attacks. SCTP does not have this vulnerability.

SCTP ignores the source address list in INIT chunks when searching for Transmission Control Block matches in opposition to <rfc4460.txt> section 2.6. This is because the procedure described there introduces severe vulnerability to DoS attacks by revealing detailed information about existing associations. SCTP does not have this vulnerability.

SCTP does not implement the UDP-like interface of <draft-ietf-tsvwg-sctpsocket-07.txt>. This is because the socket interface presented in that draft provides unorthodox interface to a ‘SOCK_SEQPACKET’ socket which is against both the traditional and standard usage of ‘SOCK_SEQPACKET’ sockets in BSD, XNS 5.2, and POSIX. In BSD, XNS 5.2 and POSIX, ‘SOCK_SEQPACKET’ sockets are strictly connection-oriented, whereas in this draft they are connectionless. A connectionless use of ‘SOCK_SEQPACKET’ would conflict with common standard socket code used by X.25, AX.25, DECNET, and other users of ‘SOCK_SEQPACKET’ sockets.

Although similar, SCTP does not implement the TCP-like interface of <draft-ietf-tsvwg-sctpsocket-07.txt>. This is because the ‘SOCK_STREAM’ socket interface presented in that draft only provides limited compatibility with tcp(7). The tcp(7) compatible socket interface provided by SCTP more closely follows the tcp(7) interface making it suitable to use SCTP as a drop-in replacement for tcp(7) with minimal (‘IPPROTO_SCTP’) adjustment to applications programs written to tcp(7).

SCTP has way too many options. This is mostly because SCTP is an new protocol and experimentation with the protocol is high. These options provide close control of the interesting features of the protocol. Unfortunately, when all options are compiled, the performance of SCTP is necessarily impacted. Many of these options will become deprecated in future releases. Portable programs should minimize their use of SCTP-specific socket options.

Although SCTP permits the user maximum control over the various SCTP protocol parameters, it is also possible to set protocol parameters in violation of the requirements of RFC 2960 and subsequent SCTP drafts and RFCs. Internet applications should take extreme care with protocol parameter settings, by either using the default values for all protocol parameters (as recommended in RFC 2960 and others) or by taking care not to adjust protocol parameters outside the ranges recommended in RFC 2960 and subsequent RFCs.

SCTP does not currently support IPv6.

SCTP host name addresses are not supported.

SCTP does not implement MOBILE-SCTP extensions due to Intellectual Property Rights claims made against the technologies in MOBILE-SCTP.

SCTP does not currently support tcp(7) undocumented Linux sendpage(2) socket call.

Transparent proxy options and other enhanced IP capabilities available with the kernel configuration parameter ‘CONFIG_SCTP_EXTENDED_IP_SUPPORT’ are not described, or not implemented.

Providing destination addresses to send(2), sendto(2) and sendmsg(2) does not work as described (it is largely ignored).

‘SOCK_RDM’ sockets are not fully supported as described.

The use of ‘SO_BINDTODEVICE’, ‘IP_OPTIONS’, ‘IP_PKTINFO’, ‘IP_RECVOPTS’, ‘IP_RETOPTS’ and ‘SCTP_STATUS’ socket options are not fully implemented and will probably not work as described.

AUTHOR

Brian F. G. Bidulock.
The OpenSS7 Project.

4 Conformance

5 Releases

This is the OpenSS7 Release of the OpenSS7 Linux Native SCTP tools, drivers and modules used with Linux.

The following sections provide information on OpenSS7 Linux Native SCTP releases as well as compatibility information of OpenSS7 release to mainstream UNIX releases of the core, modules and drivers, as well as Linux kernel compatibility.

5.1 Prerequisites

The quickest and easiest way to ensure that all prerequisites are met is to download and install this package from within the OpenSS7 Master Package, openss7-0.9.2.G, instead of separately.

Prerequisites for the OpenSS7 Linux Native SCTP package are as follows:

1. Linux distribution, somewhat Linux Standards Base compliant, with a 2.4 or 2.6 kernel and the appropriate tool chain for compiling out-of-tree kernel modules. Most recent Linux distributions are usable out of the box, but some development packages must be installed. For more information, see Compatibility.

   	− A fairly LSB compliant GNU/Linux distribution.9
   	− Linux 2.4 kernel (2.4.10 - 2.4.27).
   	− glibc2 or better.
   	− GNU groff (for man pages).10
   	− GNU texinfo (for info files).

If you need to rebuild the package from sources with modifications, you will need a larger GNU tool chain as described in See Downloading from CVS.

5.2 Compatibility

This section discusses compatibility with major prerequisites.

5.2.1 GNU/Linux Distributions

OpenSS7 Linux Native SCTP is compatible with the following Linux distributions:¹¹

• CentOS Enterprise Linux 3.4 (centos34) TBD
• CentOS Enterprise Linux 4.0 (centos4) TBD
• CentOS Enterprise Linux 4.92 (centos49) TBD
• CentOS Enterprise Linux 5.0 (centos5)
• CentOS Enterprise Linux 5.1 (centos51)
• CentOS Enterprise Linux 5.2 (centos52)
• Debian 3.0r2 Woody (deb3.0) TBD
• Debian 3.1r0a Sarge (deb3.1) TBD
• Debian 4.0r1 Etch (deb4.0)
• Debian 4.0r2 Etch (deb4.0)
• Debian 4.0r3 Etch (deb4.0)
• Fedora Core 1 (FC1) TBD
• Fedora Core 2 (FC2) TBD
• Fedora Core 3 (FC3) TBD
• Fedora Core 4 (FC4) TBD
• Fedora Core 5 (FC5) TBD
• Fedora Core 6 (FC6) TBD
• Fedora 7 (FC7)
• Fedora 8 (FC8)
• Fedora 9 (FC9)
• Gentoo 2006.1 (untested) TBD
• Gentoo 2007.1 (untested) TBD
• Lineox 4.026 (LEL4) TBD
• Lineox 4.053 (LEL4) TBD
• Mandrakelinux 9.2 (MDK92) TBD
• Mandrakelinux 10.0 (MDK100) TBD
• Mandrakelinux 10.1 (MDK101) TBD
• Mandriva Linux LE2005 (MDK102) TBD
• Mandriva Linux LE2006 (MDK103) TBD
• Mandriva One (untested)
• RedHat Linux 7.2 (RH7)
• RedHat Linux 7.3 (RH7)
• RedHat Linux 8.0 (RH8) TBD
• RedHat Linux 9 (RH9) TBD
• RedHat Enterprise Linux 3.0 (EL3) TBD
• RedHat Enterprise Linux 4 (EL4)
• RedHat Enterprise Linux 5 (EL5)
• SuSE 8.0 Professional (SuSE8.0) TBD
• SuSE 9.1 Personal (SuSE9.1) TBD
• SuSE 9.2 Professional (SuSE9.2) TBD
• SuSE OpenSuSE (SuSEOSS) TBD
• SuSE 10.0 (SuSE10.0) TBD
• SuSE 10.1 (SuSE10.1) TBD
• SuSE 10.2 (SuSE10.2) TBD
• SuSE 10.3 (SuSE10.3) TBD
• SuSE 11.0 (SuSE11.0)
• SLES 9 (SLES9) TBD
• SLES 9 SP2 (SLES9) TBD
• SLES 9 SP3 (SLES9) TBD
• SLES 10 (SLES10)
• Ubuntu 5.10 (ubu5.10) TBD
• Ubuntu 6.03 LTS (ubu6.03) TBD
• Ubuntu 6.10 (ubu6.10) TBD
• Ubuntu 7.04 (ubu7.04) TBD
• Ubuntu 7.10 (ubu7.10)
• Ubuntu 8.04 (ubu8.04)
• WhiteBox Enterprise Linux 3.0 (WBEL3) TBD
• WhiteBox Enterprise Linux 4 (WBEL4) TBD

When installing from the tarball (see Installing the Tar Ball), this distribution is probably compatible with a much broader array of distributions than those listed above. These are the distributions against which the current maintainer creates and tests builds.

5.2.2 Kernel

The OpenSS7 Linux Native SCTP package compiles as a Linux kernel module. It is not necessary to patch the Linux kernel to build or use the package.¹² Nor do you have to recompile your kernel to build or use the package. OpenSS7 packages use autoconf scripts to adapt the package source to your existing kernel. The package builds and runs nicely against production kernels from the distributions listed above. Rather than relying on kernel versions, the autoconf scripts interrogate the kernel for specific features and variants to better adapt to distribution production kernels that have had patches applied over the official kernel.org sources.

The OpenSS7 Linux Native SCTP package is compatible with 2.4 kernel series after 2.4.10 and has been tested up to and including 2.4.27. It has been tested from 2.6.3 up to and including 2.6.26 (with Fedora 9, openSUSE 11.0 and Ubuntu 8.04 patchsets). Please note that your mileage may vary if you use a kernel more recent than 2.6.26.4: it is difficult to anticipate changes that kernel developers will make in the future. Many kernels in the 2.6 series now vary widely by release version and if you encounter problems, try a kernel within the supported series.

UP validation testing for kernels is performed on all supported architectures. SMP validation testing was initially performed on UP machines, as well as on an Intel 3.0GHz Pentium IV 630 with HyperThreading enabled (2x). Because HyperThreading is not as independent as multiple CPUs, SMP validation testing was limited. Current releases have been tested on dual 1.8GHz Xeon HP servers (2x) as well as dual quad-core SunFire (8x) servers.

It should be noted that, while the packages will configure, build and install against XEN kernels, that problems running validation test suites against XEN kernels has been reported. XEN kernels are explicitly not supported. This may change at some point in the future if someone really requires running OpenSS7 under a XEN kernel.

5.2.3 Architectures

The OpenSS7 Linux Native SCTP package compiles and installs on a wide range of architectures. Although it is believed that the package will work on all architectures supported by the Linux kernel being used, validation testing has only been performed with the following architectures:

• ix86
• x86_64
• ppc (MPC 860)
• ppc64

32-bit compatibility validation testing is performed on all 64-bit architectures supporting 32-bit compatibility. If you would like to validate an OpenSS7 package on a specific machine architecture, you are welcome to sponsor the project with a test machine.

5.3 Release Notes

The sections that follow provide information on OpenSS7 releases of the OpenSS7 Linux Native SCTP package.

Major changes for release sctp-0.2.27

This is the twenty-seventh release of the Linux Native (Sockets) SCTP from the OpenSS7 Project. This release, as with other releases, on builds and installs on 2.4 kernels. This package is not as important to the OpenSS7 Project as the STREAMS version of SCTP, which provides the basis for all of the SIGTRAN components for the OpenSS7 stacks. Also, the STREAMS version runs on both 2.4 and 2.6 kernels.

This is a stable production release: it deprecates previous releases. Please upgrade to the current release before reporting bugs.

This is primarily a maintenance release correcting reported bugs, but also includes the latest packaging improvements.

Major features since the last public release are as follows:

• Minor documentation corrections.
• Kernel module license made explicit "GPL v2". And then changed back to "GPL".
• License upgrade to AGPL Version 3.
• Ability to strap out major documentation build and installation primarily for embedded targets.
• Improvements to common build process for embedded and cross-compile targets.
• Updated tool chain to m4-1.4.12, autoconf-2.63 and texinfo-4.13.
• Conversion of RPM spec files to common approach for major subpackages.
• Updated references database for manual pages and roff documents.
• Build system now builds yum(8) repositories for RPMs and apt-get(8) repositories for DEBs. Installation documentation has been updated to include details of repository install sourcesref.
• Added MODULE_VERSION to all modules and drivers.

This is a public stable production grade release of the package: it deprecates previous releases. Please upgrade to the current release before reporting bugs.

As with other OpenSS7 releases, this release configures, compiles, installs and builds RPMs and DEBs for a wide range of Linux 2.4 and 2.6 RPM- and DPKG-based distributions, and can be used on production kernels without patching or recompiling the kernel.

This package is publicly released under the GNU Affero General Public License Version 3. The release is available as an autoconf tarball, SRPM, DSC, and set of binary RPMs and DEBs. See the downloads page for the autoconf tarballs, SRPMs and DSCs. For tarballs, SRPMs, DSCs and binary RPMs and DEBs, see the sctp package page.

See http://www.openss7.org/codefiles/sctp-0.2.27/ChangeLog and http://www.openss7.org/codefiles/sctp-0.2.27/NEWS in the release for more information. Also, see the sctp.pdf manual in the release (also in html http://www.openss7.org/sctp_manual.html).

For the news release, see http://www.openss7.org/rel20081029_2.html.

Major changes for release sctp-0.2.26

This is the twenty-sixth release of the Linux Native (Sockets) SCTP from the OpenSS7 Project. This release, as with other releases, on builds and installs on 2.4 kernels. This package is not as important to the OpenSS7 Project as the STREAMS version of SCTP, which provides the basis for all of the SIGTRAN components for the OpenSS7 stacks. Also, the STREAMS version runs on both 2.4 and 2.6 kernels.

This is a stable production release: it deprecates previous releases. Please upgrade to the current release before reporting bugs.

This is primarily a maintenance release correcting reported bugs, but also includes the latest packaging improvements.

Major features since the last public release are as follows:

• Support build on openSUSE 10.2.
• Support build on Fedora 7 with 2.6.21 kernel.
• Support build on CentOS 5.0 (RHEL5).
• Support build on Ubuntu 7.04.
• Updated to gettext 0.16.1.
• Changes to support build on 2.6.20-1.2307.fc5 and 2.6.20-1.2933.fc6 kernel.
• Supports build on Fedora Core 6.
• Support for recent distributions and tool chains.

Major changes for release sctp-0.2.25

This is the twenty-fifth release of the Linux Native (Sockets) SCTP from the OpenSS7 Project. This release, as with other releases, on builds and installs on 2.4 kernels. This package is not as important to the OpenSS7 Project as the STREAMS version of SCTP, which provides the basis for all of the SIGTRAN components for the OpenSS7 stacks. Also, the STREAMS version runs on both 2.4 and 2.6 kernels.

This is a stable production release: it deprecates previous releases. Please upgrade to the current release before reporting bugs.

This is primarily a maintenance release correcting reported bugs, but also includes the latest packaging improvements.

Major features since the last public release are as follows:

• Support for autoconf 2.61, automake 1.10 and gettext 0.16.
• Support for Ubuntu 6.10 distribution and bug fixes for i386 kernels.

Major changes for release sctp-0.2.24

This is the twenty-fourth release of the Linux Native (Sockets) SCTP from the OpenSS7 Project. This release, as with other releases, on builds and installs on 2.4 kernels. This package is not as important to the OpenSS7 Project as the STREAMS version of SCTP, which provides the basis for all of the SIGTRAN components for the OpenSS7 stacks. Also, the STREAMS version runs on both 2.4 and 2.6 kernels.

This is a stable production release: it deprecates previous releases. Please upgrade to the current release before reporting bugs.

This is primarily a maintenance release correcting reported bugs, but also includes the latest packaging improvements.

Following are highlights of some of the changes since the last release:

• Support for (configure but not build on) most recent 2.6.18 kernels (including Fedora Core 5 with inode diet patch set).
• Added send-pr scripts for automatic problem report generation.
• Now builds 32-bit compatibility libraries and tests them against 64-bit kernel modules and drivers. The ‘make installcheck’ target will now automatically test both 64-bit native and 32-bit compatibility versions, one after the other, on 64-bit platforms.
• Improved compiler flag generation and optimizations for recent gcc compilers and some idiosyncratic behaviour for some distributions (primarily SUSE).
• Optimized compilation is now available also for user level programs in addition to kernel programs. Added new --with-optimize option to configure to accomplish this.
• Better detection of SUSE distributions, release numbers and SLES distributions: support for additional SuSE distributions on ix86 as well as x86_64. Added distribution support includes SLES 9, SLES 9 SP2, SLES 9 SP3, SLES 10, SuSE 10.1.
• Many documentation updates for all OpenSS7 packages. Automated release file generation making for vastly improved and timely text documentation present in the release directory.
• Added --disable-devel configure option to suppress building and installing development environment. This feature is for embedded or pure runtime targets that do not need the development environment (static libraries, manual pages, documentation).
• Added send-pr script for automatic problem report generation.
• Fixed problems with unresolved symbols on some systems. Fixed glaring error in sctp_init preventing kernel module from loading.
• Added init scripts and system control configuration data. Removed old preload approach to kernel module loading.

Major changes for release sctp-0.2.23

Corrections for and testing of 64-bit clean compile and test runs on x86_64 architecture. Some bug corrections resulting from gcc 4.0.2 compiler warnings.

Corrected build flags for Gentoo and 2.6.15 kernels as reported on mailing list.

Major changes for release sctp-0.2.22

This is primarily a bug fixes release and corrections resulting from testing. This is a major bug fix release. The previous release was largely untested.

Major changes for release sctp-0.2.21

With this release version numbers were changed to reflect an upstream version only to be consistent with other OpenSS7 package releases. All RPM release numbers will be ‘-1$(PACKAGE_RPMEXTRA)’ and all Debian release numbers will be ‘_0’. If you wish to apply patches and release the package, please bump up the release number and apply a suitable release suffix for your organization. We leave Debian release number ‘_1’ reserved for your use, so you can still bundle the source in the .dsc file.

Improved build process.

Not publicly released.

Initial release sctp-0.2.20-1

Initial autoconf/RPM packaging of the sctp release.

The OpenSS7 Linux Native SCTP existed before as a kernel patch for the Linux kernel. This is an autoconf/rpm packaging release of Linux Native SCTP that builds and installs separate from the Linux kernel tree.

Not publicly released.

5.4 Maturity

The OpenSS7 Project adheres to the following release philosophy:

• pre-alpha release
• alpha release
• beta release
• gamma release
• production release
• unstable release

5.4.1 Pre-Alpha Releases

Pre-alpha releases are releases that have received no testing whatsoever. Code in the release is not even known to configure or compile. The purpose of a pre-alpha release is to make code and documentation available for inspection only, and to solicit comments on the design approach or other characteristics of the software package.

Pre-alpha release packages ship containing warnings recommending that the user not even execute the contained code.

5.4.2 Alpha Releases

Alpha releases are releases that have received little to no testing, or that have been tested and contains known bugs or defects that make the package unsuitable even for testing. The purpose for an alpha release are the same as for the pre-alpha release, with the additional purpose that it is an early release of partially functional code that has problems that an external developer might be willing to fix themselves and contribute back to the project.

Alpha release packages ship containing warnings that executing the code can crash machines and might possibly do damage to systems upon which it is executed.

5.4.3 Beta Releases

Beta releases are releases that have received some testing, but the testing to date is not exhaustive. Beta release packages do not ship with known defects. All known defects are resolved before distribution; however, as exhaustive testing has not been performed, unknown defects may exist. The purpose for a beta release is to provide a baseline for other organizations to participate in the rigorous testing of the package.

Beta release packages ship containing warnings that the package has not been exhaustively tested and that the package may cause systems to crash. Suitability of software in this category for production use is not advised by the project; however, as always, is at the discretion of the user of the software.

5.4.4 Gamma Releases

Gamma releases are releases that have received exhaustive testing within the project, but external testing has been minimal. Gamma release packages do not ship with known defects. As exhaustive internal testing has been performed, unknown defects should be few. Please remember that there is NO WARRANTY on public release packages.

Gamma release packages typically resolve problems in previous beta releases, and might not have had full regression testing performed. Suitability of software in this category for production use is at the discretion of the user of the software. The OpenSS7 Project recommends that the complete validation test suites provided with the package be performed and pass on target systems before considering production use.

5.4.5 Production Releases

Production releases are releases that have received exhaustive testing within the project and validated on specific distributions and architectures. Production release packages do not ship with known defects. Please remember that there is NO WARRANTY on public release packages.

Production packages ship containing a list of validated distributions and architectures. Full regression testing of any maintenance changes is performed. Suitability of software in this category for production use on the specified target distributions and architectures is at the discretion of the user. It should not be necessary to preform validation tests on the set of supported target systems before considering production use.

5.4.6 Unstable Releases

Unstable releases are releases that have received extensive testing within the project and validated on a a wide range of distributions and architectures; however, is has tested unstable and found to be suffering from critical problems and issues that cannot be resolved. Maintenance of the package has proved impossible. Unstable release packages ship with known defects (and loud warnings). Suitability of software in this category for production use is at the discretion of the user of the software. The OpenSS7 Project recommends that the problems and issues be closely examined before this software is used even in a non-production environment. Each failing test scenario should be completely avoided by the application. OpenSS7 beta software is more stable that software in this category.

5.5 Bugs

5.5.1 Defect Notices

OpenSS7 Linux Native SCTP could contain unknown defects. This is a beta release. Some defects could be harmful. Validation testing has been performed by the OpenSS7 Project on this software for only a restricted set of systems. The software might fail to configure or compile on other systems. The OpenSS7 Project recommends that you do not use this software for purposes other than validation testing and evaluation, and then only with care. Use at your own risk. Remember that there is NO WARRANTY.¹³

This software is beta software. As such, it might crash your kernel. Installation of the software might mangle your header files or Linux distribution in such a way as to make it unusable. Crashes could lock your system and rebooting the system might not repair the problem. You can possibly lose all the data on your system. Because this software might crash your kernel, the resulting unstable system could possibly destroy computer hardware or peripherals making them unusable. You might void the warranty on any system on which you run this software. YOU HAVE BEEN WARNED.

5.5.2 Known Defects

With the exception of packages not originally created by the OpenSS7 Project, the OpenSS7 Project software does not ship with known bugs in any release stage except pre-alpha. OpenSS7 Linux Native SCTP had no known bugs at the time of release.

5.5.3 Defect History

This section contains historical bugs that were encountered during development and their resolutions. This list serves two purposes:

1. It captures bugs encountered between releases during development that could possibly reoccur (and the Moon is made of blue cheese). It therefore provides a place for users to look if they encounter a problem.
2. It provides a low overhead bug list between releases for developers to use as a TODO list.

Bugs

(no items)

5.6 Schedule

Current Plan

The current plan is to largely abandon the OpenSS7 Linux Native Sockets version of SCTP. It was developed for inclusion into mainline and only currently compiles for 2.4 kernels. The OpenSS7 STREAMS version of SCTP (the strsctp package) implements the same protocol engine core and compiles and installs for 2.4 and 2.6 kernels. The STREAMS version meets the needs of the OpenSS7 Project better: implementing SIGTRAN as pushable modules and multiplexing drivers and allows signalling gateways to be built without messages crossing the user-kernel boundary. Therefore, it is unlikely that this version will have any further development. See the TODO file in the strsctp package for more information on the current plan for that package.

Nevertheless, the project will continue to build and release this SCTP package against 2.4 kernels and it will continue to be part of the Master Package for some time to come.

Things to Do

• Perform conformance and performance testing on the sctp-0.2.22 release.

  For conformance testing, my intention was to use the same conformance test tool and available in the strsctp (OpenSS7 STREAMS SCTP) package. This test tool uses the ability to directly send and intercept SCTP packets at the IP level.

  For performance testing, my intention was to use the iperf (OpenSS7 Modified Iperf) package.

• Perform x86_64 HT SMP testing on sctp-0.2.22.

Things to do to convert to autoconf: (2006-02-23)

• Check for IPPROTO_SCTP = 132 in /usr/include/netinet/in.h it should be there on more recent releases. It is there as a define as well as an enum. Therefore it is enough to add #ifndef IPPROTO_SCTP to user files, but it is not as a define in linux/in.h so we will have to run a check against kernel headers.

  *done*

  What I did was add the #ifndef the hooks.h file included after all other includes. That way if the enum is there and not the define, the define gets done anyway.

• We have our own linux/sctp.h Our linux/sctp.h is not installed. You will find the lksctp linux/sctp.h in the headers for some more recent c headers. It is lucky it is really in the wrong place: it should be in netinet/sctp.h for user programs. That is where we install the header file.

  *done*

  Our header installs in netinet/sctp.h and has name space pollution protection.

• We need to override the struct sk_buff definition from linux/skbuff.h to include the sctphdr in the h (transport header) union. We are in real trouble if the size of sctphdr exceeds the existing union.

  *done*

  What I did was change all references to h.sh to use the macro SCTP_SKB_SH that was already defined. The definition of SCTP_SKB_SH is based on the presence or absence of this field. This field is, however, normally absent because lksctp failed to fill it in.

  We don't have to check the size of this because the transport header union is a union of pointers. What needs to be checked here is the size of the control block in the sk_buff (sizeof sk_buff.cb) against the size of our sctp_skb_cb structure that we cast the control block to. This was done using a compiler trick to compare sizes of complex data structures.

• We need to define SOL_SCTP that should be in linux/socket.h for the socket layer. Some lksctp kernels already have it defined. It needs to be the protocol number of 132 so there is no conflict there.

  *done*

  Same treatment as IPPROTO_SCTP above.

• We need to add sysctl definitions for /proc/sys/net/ipv4 to linux/sysctl.h Again, I added these to /proc/sys/net/ipv4 whereas lksctp adds to /proc/sys/net/sctp. So there is no conflict. I don't know whether we should jump the number high enough that it does not conflict with any latter additions to /proc/sys/net/ipv4 or whether to determine the last index at build time. We should also override the /usr/include/linux/sysctl.h version with a patched version. It may be necessary to patch out conflicting SCTP names.
• We need definitions for inet_sctp_ops (struct proto_ops) and need external definitions for inet_bind(), inet_multi_getname() and inet_ioctl() that are all missing from net/inet_common.h

  *done*

  The necessary symbols have been ripped in acinclude.m4 and hooked in

• We have our own net/sctp.h lksctp doesn't have one so we're ok there.

  *done*

  Yes, we just include it.

• net/snmp.h needs definitions for SCTP mibs. lksctp has stolen ours here but have missed some definitions: SctpMaxAssoc and SctpDiscontinuityTime. Fortunately we don't really use these two. Unfortunately, lksctp versions are not cacheline_aligned. As it is only a structure definition, we don't need to override it, but could anyway.

  *done*

  We override the mib definition with our own from net/net_snmp.h

• We need to override struct sock in net/sock.h to include sctp_opt for af_sctp On earlier kernels we can simply override the struct but must check that the tp_pinfo union has sufficient size for our definitions. On latter kernels, lksctp includes there own definition here, but perhaps we can pull some "define" tricks when CONFIG_IP_SCTP_MODULE was set to override them.

  *done*

  tp_pinfo is too small, so I defined our sctp_opt structure to span both tp_pinfo and protinfo private fields. Configure checks that the spanning is correct and that there is sufficient room in the overlaid structure.

• Unexported netsyms: we will have to rip the following symbols if not exported:

            EXPORT_SYMBOL(icmp_err_convert);
            EXPORT_SYMBOL(icmp_statistics);
            EXPORT_SYMBOL(inet_bind)
            EXPORT_SYMBOL(inet_ioctl)
            EXPORT_SYMBOL(inet_multi_getname)
            EXPORT_SYMBOL(ip_build_and_send_pkt);
            EXPORT_SYMBOL(ip_cmsg_send);
            EXPORT_SYMBOL(ip_getsockopt);
            EXPORT_SYMBOL(ip_options_echo);
            EXPORT_SYMBOL(ip_rt_min_pmtu);
            EXPORT_SYMBOL(ip_rt_mtu_expires);
            EXPORT_SYMBOL(ip_rt_update_pmtu);
            EXPORT_SYMBOL(ip_setsockopt);
            EXPORT_SYMBOL(sysctl_ip_dynaddr);
            EXPORT_SYMBOL(sysctl_ip_nonlocal_bind);
            EXPORT_SYMBOL(sysctl_rmem_default)
            EXPORT_SYMBOL(sysctl_wmem_default)
  

  *done*

  Actually, we rip a longer list as follows:

            EXPORT_SYMBOL(icmp_err_convert);
            EXPORT_SYMBOL(icmp_statistics);
            EXPORT_SYMBOL(inet_bind);
            EXPORT_SYMBOL(inet_getname);
            EXPORT_SYMBOL(inet_ioctl);
            EXPORT_SYMBOL(inet_multi_getname);
            EXPORT_SYMBOL(ip_cmsg_send);
            EXPORT_SYMBOL(ip_getsockopt);
            EXPORT_SYMBOL(ip_route_output_flow);
            EXPORT_SYMBOL(__ip_route_output_key);
            EXPORT_SYMBOL(ip_rt_min_pmtu);
            EXPORT_SYMBOL(ip_rt_mtu_expires);
            EXPORT_SYMBOL(ip_rt_update_pmtu);
            EXPORT_SYMBOL(ipsec_sk_policy);
            EXPORT_SYMBOL(ip_setsockopt);
            EXPORT_SYMBOL(sysctl_ip_dynaddr);
            EXPORT_SYMBOL(sysctl_ip_nonlocal_bind);
            EXPORT_SYMBOL(__xfrm_policy_check);
            EXPORT_SYMBOL(xfrm_policy_delete);
            EXPORT_SYMBOL(__xfrm_sk_clone_policy);
  

  ( even a longer list now... )

• We need to figure out what to do net/ipv4/af_inet.c to get sctp to autoload correctly. Also, we need to override any other loaded sctp.

  *done*

  We override lksctp by moving it out of the way to sctp_deprecated. As far as autoloading is concerned we will have to load it manually to begin with.

• lksctp doesn't adjust the ext_header_len in net/ipv4/ip_sockglue when IP options are set on the socket. We might have to find some way to intercept socket option IP_OPTIONS.

  *addressed*

  IP layer will just have to pull up the sk_buff if there is not enough headroom.

• Reporting snmp statistics. lksctp doesn't do this right (i.e. netstat broken.) Although we can generate our own sctp_get_info, we need to wrapper snmp_get_info and afinet_get_info. We can do this by ripping these symbols, indexing into the proc directory structures and then stabbing them. Or we could destroy them and recreate them with the wrapper. All we have to do is print our SCTP info first and then call the wrapper function for both snmp_get_info and afinet_get_info.

  *done*

  I wrote wrappers for both snmp_get_info and afinet_get_info and reload the new version in the right place on module load and unload them later. sctp_get_info is defined and loaded under /proc/net/sctp.

• For sysctl we used to just add our entries to /proc/sys/net/ipv4 in the kernel We might be able to just jam the ipv4_table pointer in net_table to point to a new table which includes the SCTP entries.

  *done*

  Entries added as before. Indexes start at 200 to avoid conflict with other entries at that level.

... And that's it. Just add compile our sctp.c file with our headers. The loading step might be the toughest.

5.7 History

For the latest developments with regard to history of changes, please see the ChangeLog file in the release package.

6 Installation

6.1 Repositories

The OpenSS7 Linux Native SCTP package release can be accessed from the repositories of The OpenSS7 Project. For rpm(1) based systems, the package is available in a yum(8) repository based on repomd XML and may also be accessed using zypper(8) or yast(8). For dpkg(1) based systems, the package is available in a apt(8) repository.

By far the easiest (most repeatable and manageable) form for installing and using OpenSS7 packages is to install packages from the yum(8) or apt(8) repositories. If your distribution does not support yum(8), zypper(8), yast(8) or apt(8), then it is still possible to install the RPMs or DEBs from the repositories using rpm(1), dpkg(1); or by using wget(1) and then installing them from RPM or DEB using rpm(1) or dpkg(1) locally.

If binaries are not available for your distribution or specific kernel, but your distribution supports rpm(1) or dpkg(1), the next best method for installing and using OpenSS7 packages is to download and rebuild the source RPMs or DSCs from the repository. This can also be performed with yum(8), zypper(8), yast(8), apt(8); or directly using wget(1), rpm(1) or dpkg(1).

If your architecture does not support rpm(1) or dpkg(1) at all, or you have special needs (such as cross-compiling for embedded targets), the final resort method is to download, configure, build and install from tarball. In this later case, the easiest way to build and install OpenSS7 packages from tarball is to use the tarball for the OpenSS7 Master Package, openss7-0.9.2.G.

6.1.1 Repositories for YUM

To install or upgrade from the OpenSS7 repomd repositories, you will need a file in your /etc/yum.repo.d/ directory. This file can be obtained directly from the OpenSS7 repository, like so:

     $> REPOS="http://www.openss7.org/repos/rpms"
     $> wget $REPOS/centos/5.2/x86_64/repodata/openss7.repo
     $> sudo cp -f openss7.repo /etc/yum.repo.d/
     $> sudo yum makecache

This example assumes the the distribution is ‘centos’ and the distribution release is ‘5.2’ and the architecture requires is ‘x86_64’. Another example would be $REPOS/i686/suse/11.0/i686/repodata/openss7.repo, for using yum(8) with SUSE.

Once the repository is set up, OpenSS7 includes a number of virtual package definitions that eas the installation and removal of kernel modules, libraries and utilities. Downloading, configuring, building and installation for a single-kernel distribution is as easy as:

     $> sudo yum install sctp

Removing the package is as easy as:

     $> sudo yum remove sctp

If you have difficulty downloading the openss7.repo file, edit the following information into the file and place it into the /etc/yum.repo.d/openss7.repo file:

     -| [openss7]
     -| enabled = 1
     -| name = OpenSS7 Repository
     -| baseurl = http://www.openss7.org/repos/rpms/centos/5.2/x86_64
     -| gpgcheck = 1
     -| gpgkey = http://www.openss7.org/pubkey.asc

Note that it is also possible to point to these repositories as an additional installation source when installing CentOS, RedHat, Fedora, or others. You will have an additional STREAMS category from which to choose installation packages.

Some additional installation real or virtual package names and the installations they accomplish are as follows:

‘sctp’

This package can be used to install or remove the entire OpenSS7 Linux Native SCTP package. When installing, kernel modules will be installed automatically for the highest version kernel on your system. When removing, all corresponding kernel modules will also be removed.

‘sctp-devel’

This package can be used to install or remove the development components of the OpenSS7 Linux Native SCTP package. When installing, ‘sctp’ and appropriate kernel module and kernel module development and debug packages will also be installed. When removing, the development package and all kernel module development and debug packages will also be removed.

‘sctp-2.4.20-28.7’

This package can be used to install or remove the package for a specific kernel version. When installing, the ‘sctp’ package will also be installed if necessary. When removing the last kernel module package, the ‘sctp’ package will also be removed.

Note that the version ‘2.4.20-28.7’ is just an example. Use the version returned by ‘$(uname -r)’ for the kernel for which you wish to install or remove the packages.

‘sctp-2.4.20-28.7-devel’

This package can be used to install or remove the development and debug packages for a specific kernel version. When installing, the ‘sctp’ and ‘sctp-devel’ packages will also be installed if necessary. When removing the development and debug for kernel modules for the last kernel, the ‘sctp-devel’ package will also be removed.

Note that the version ‘2.4.20-28.7’ is just an example. Use the version returned by ‘$(uname -r)’ for the kernel for which you wish to install or remove the packages.

For assistance with specific RPMs, see Downloading the Binary RPM.

6.1.2 Repositories for APT

For assistance with specific DEBs, see Downloading the Debian DEB.

6.2 Downloading

The OpenSS7 Linux Native SCTP package releases can be downloaded from the downloads page of The OpenSS7 Project. The package is available as a binary RPM (for popular architectures) a source RPM, Debian binary DEB and source DSC, or as a tar ball. If you are using a browsable viewer, you can obtain the OpenSS7 release of SCTP from the links in the sections that follow.

By far the easiest (most repeatable and manageable) form for installing and using OpenSS7 packages is to download and install individual packages from binary RPM or DEB. If binary RPMs or DEBs are not available for your distribution, but your distribution supports rpm(1) or dpkg(1), the next best method for installing and using OpenSS7 packages is to download and rebuild the source RPMs or DSCs.

If your architecture does not support rpm(1) or dpkg(1) at all, or you have special needs (such as cross-compiling for embedded targets), the final resort method is to download, configure, build and install from tarball. In this later case, the easiest way to build and install OpenSS7 packages from tarball is to use the tarball for the OpenSS7 Master Package, openss7-0.9.2.G.

6.2.1 Downloading with YUM

OpenSS7 repositories support yum(8) and zypper(8) in repomd XML format as well as YaST and YaST2 formats.

OpenSS7 includes virtual packages that ease the installation and removal of kernel modules, libraries and utilities. Downloading, configuration, building and installation for a signle-kernel distribution installation is as easy as:

     % sudo yum install sctp

This and additional packages for installation are detailed as follows:

sctp

Install this package if you need the runtime sctp package.

          % sudo yum install sctp

This will install the sctp, sctp-lib and sctp-KVERSION RPMs, where ‘KVERSION’ is the highest version number kernel on your system.

Remove this package if you need to remove all vestages of the sctp package.

          % sudo yum remove sctp

This will remove the sctp, sctp-lib, sctp-devel, sctp-KVERSION and sctp-devel-KVERSION RPMs for all kernels on your system.

sctp-devel

Install this package if you need the development sctp package.

          % sudo yum install sctp-devel

This will install the sctp, sctp-lib, sctp-devel, sctp-KVERSION and sctp-devel-KVERSION RPMs, where ‘KVERSION’ is the highest version number kernel on your system.

Remove this package if you do not need development capabilities for the sctp package for any kernel.

          % sudo yum remove sctp-devel

This will remove the sctp-devel and sctp-devel-KVERSION RPMs for all kernels on your system.

sctp-2.4.20-28.7

Install this package if you need the runtime sctp for kernel version ‘2.4.20-28.7’. The value ‘2.4.20-28.7’ is just an example. For the running kernel, you can install the runtime sctp components with:

          % sudo yum install sctp-$(uname -r)

This will install the sctp, sctp-lib and sctp-2.4.20-28.7 RPMs, where ‘2.4.20-28.7’ is the kernel version specified.

Remove this package if you no longer need the runtime sctp for kernel version ‘2.4.20-28.7’. The value ‘2.4.20-28.7’ is just an example. For the running kernel, you can remove the runtime sctp components with:

          % sudo yum remove sctp-$(uname -r)

This will remove the sctp-2.4.20-28.7 and sctp-devel-2.4.20-28.7 RPMs, where ‘2.4.20-28.7’ is the kernel version specified. Also, if this is the last kernel for which sctp was installed, the sctp sctp-lib and sctp-devel RPMs will also be removed.

Note that this is a virtual package name: the actual RPMs installed or removed from the system is a kernel module package whose precise name will depend upon the system being used.

sctp-devel-2.4.20-28.7

Install this package if you need the development sctp package for kernel version ‘2.4.20-28.7’. The value ‘2.4.20-28.7’ is just an example. For the running kernel, you can install the kernel development sctp components with:

          % sudo yum install sctp-devel-$(uname -r)

This will install the sctp, sctp-lib, sctp-devel, sctp-2.4.20-28.7 and sctp-devel-2.4.20-28.7 RPMs, where ‘2.4.20-28.7’ is the kernel version specified.

Remove this package if you no longer need the development capabilities for the sctp package for kernel version ‘2.4.20-28.7’. The value ‘2.4.20-28.7’ is just an example. For the running kernel, you can remove the kernel development sctp components with:

          % sudo yum remove sctp-devel-$(uname -r)

This will remove the sctp-devel-2.4.20-28.7 RPMs, where ‘2.4.20-28.7’ is the kernel version specified. Also, if this is the last kernel for which sctp was installed, the sctp-devel RPMs will also be removed.

Note that this is a virtual package name: the actual RPMs installed or removed from the system is a kernel module package whose precise name will depend upon the system being used.

sctp-lib

This package is an auxillary package that should be removed and inserted automatically by yum(8). In rare instances you might need to remove or install this package explicitly.

6.2.2 Downloading with APT

OpenSS7 repositries support apt(8) repositorie digests and signatures.

6.2.3 Downloading the Binary RPM

To install from binary RPM, you will need several of the RPM for a complete installation. Binary RPM fall into several categories. To download and install a complete package requires the appropriate RPM from each of the several categories below, as applicable. Some release packages do not provide RPMs in each of the several categories.

To install from Binary RPM, you will need all of the following kernel independent packages for your architecture, and one of the kernel-dependent packages from the next section.

Independent RPM

Independent RPM are dependent on neither the Linux kernel version, nor the STREAMS package. For example, the source package ‘sctp-source-0.2.27-1.7.2.noarch.rpm’, is not dependent on kernel nor STREAMS package.

All of the following kernel and STREAMS independent RPM are required for your architecture. Binary RPMs listed here are for example only: additional binary RPMs are available from the downloads site. If your architecture is not available, you can build binary RPM from the source RPM (see see Building from the Source RPM).

Architecture Independent

sctp-dev-0.2.27-1.7.2.noarch.rpm

The sctp-dev package contains the device definitions necessary to run applications programs developed for OpenSS7 Linux Native SCTP.¹⁴

sctp-doc-0.2.27-1.7.2.noarch.rpm

The sctp-doc package contains this manual in plain text, postscript, pdf and html forms, along with the meta-information from the SCTP package. It also contains all of the manual pages necessary for developing OpenSS7 Linux Native SCTP applications and OpenSS7 Linux Native SCTP STREAMS modules or drivers.

sctp-init-0.2.27-1.7.2.noarch.rpm

The sctp-init package contains the init scripts and provides the ‘postinst’ scripts necessary to create kernel module preloads and modules definitions for all kernel module ‘core’ subpackages.

sctp-source-0.2.27-1.7.2.noarch.rpm

The sctp-source package contains the source code necessary for building the OpenSS7 Linux Native SCTP release. It includes the autoconf(1) configuration utilities necessary to create and distribute tarballs, rpm and deb/dsc. ¹⁵

Architecture Dependent

sctp-devel-0.2.27-1.7.2.i686.rpm

The sctp-devel package contains library archives for static compilation, header files to develop OpenSS7 Linux Native SCTP modules and drivers. This also includes the header files and static libraries required to compile OpenSS7 Linux Native SCTP applications programs.

sctp-lib-0.2.27-1.7.2.i686.rpm

The sctp-lib package contains the run-time shared libraries necessary to run application programs and utilities developed for the SCTP package. ¹⁶

STREAMS-Dependent RPM

STREAMS-Dependent RPM are dependent upon the specific STREAMS package being used, either Linux STREAMS or Linux Fast-STREAMS. Packages dependent upon Linux STREAMS will have LiS in the package name. Packages dependent upon Linux Fast-STREAMS will have streams in the package name. Note that some STREAMS-Dependent RPM are also Kernel-Dependent RPM as described below.

One of the following STREAMS-Dependent packages is required for your architecture. If your architecture is not on the list, you can build binary RPM from the source RPM (see see Building from the Source RPM).

sctp-LiS-util-0.2.27-1.7.2.i686.rpm

The sctp-LiS-util package provides administrative and configuration test utilities and commands associated with the OpenSS7 Linux Native SCTP package. Because this package must link a STREAMS-specific library, it is a STREAMS-Dependent package. Use the sctp-LiS-util package if you have LiS installed.

sctp-streams-util-0.2.27-1.7.2.i686.rpm

The sctp-streams-util package provides administrative and configuration test utilities and commands associated with the OpenSS7 Linux Native SCTP package. Because this package must link a STREAMS-specific library, it is a STREAMS-Dependent package. Use the sctp-streams-util package if you have streams installed.

Kernel-Dependent RPM

Kernel-Dependent RPM are dependent on specific Linux Kernel Binary RPM releases. Packages are provided for popular released RedHat kernels. Packages dependent upon RedHat or other kernel RPM will have the ‘_kversion’ kernel package version in the package name.

One of the following Kernel-Dependent packages is required for your architecture and kernel version. If your architecture or kernel version is not on the list, you can build binary RPM from the source RPM (see see Building from the Source RPM).¹⁷

sctp-core-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

The sctp-core package contains the loadable kernel modules that depend only on the kernel. This package is heavily tied to the kernel for which it was compiled. This particular package applies to kernel version ‘2.4.20-28.7’.¹⁸

sctp-info-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

The sctp-info package¹⁹ contains the module symbol version information for the core subpackage, above. It is possible to load this subpackage and compile modules that use the exported symbols without loading the actual kernel modules (from the core subpackage above). This package is heavily tied to the kernel for which it was compiled. This particular package applies to kernel version ‘2.4.20-28.7’.²⁰

sctp-LiS-core-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

The sctp-LiS-core package contains the kernel modules that provide the OpenSS7 Linux Native SCTP STREAMS modules and drivers. This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to LiS (Linux STREAMS) on kernel version ‘2.4.20-28.7’.²¹

sctp-streams-core-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

The sctp-streams-core package contains the kernel modules that provide the OpenSS7 Linux Native SCTP STREAMS modules and drivers. This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to streams (Linux Fast-STREAMS) on kernel version ‘2.4.20-28.7’.²²

sctp-LiS-info-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

The sctp-LiS-info package²³ contains the module symbol version information for the LiS-core subpackage, above. It is possible to load this subpackage and compile modules that use the exported symbols without loaded the actual kernel modules (from the LiS-core subpackage above). This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to LiS (Linux STREAMS) on kernel version ‘2.4.20-28.7’.²⁴

sctp-streams-info-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

The sctp-streams-info package²⁵ contains the module symbol version information for the streams-core subpackage, above. It is possible to load this subpackage and compile modules that use the exported symbols without loaded the actual kernel modules (from the streams-core subpackage above). This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to streams (Linux Fast-STREAMS) on kernel version ‘2.4.20-28.7’.²⁶

Configuration and Installation

To configure, build and install the binary RPM, See Configuring the Binary RPM.

6.2.4 Downloading the Debian DEB

To install from binary DEB, you will need several of the DEB for a complete installation. Binary DEB fall into several categories. To download and install a complete package requires the appropriate DEB from each of the several categories below, as applicable. Some release packages do not provide DEBs in each of the several categories.

To install from Binary DEB, you will need all of the following kernel independent packages for your architecture, and one of the kernel-dependent packages from the next section.

Independent DEB

Independent DEB are dependent on neither the Linux kernel version, nor the STREAMS package. For example, the source package ‘sctp-source_0.2.27-0_i386.deb’, is not dependent on kernel nor STREAMS package.

All of the following kernel and STREAMS independent DEB are required for your architecture. Binary DEBs listed here are for example only: additional binary DEBs are available from the downloads site. If your architecture is not available, you can build binary DEB from the Debian DSC (see see Building from the Debian DSC).

Architecture Independent

sctp-dev_0.2.27-0_all.deb

The sctp-dev package contains the device definitions necessary to run applications programs developed for OpenSS7 Linux Native SCTP. ²⁷

sctp-doc_0.2.27-0_all.deb

The sctp-doc package contains this manual in plain text, postscript, pdf and html forms, along with the meta-information from the SCTP package. It also contains all of the manual pages necessary for developing OpenSS7 Linux Native SCTP applications and OpenSS7 Linux Native SCTP STREAMS modules or drivers.

sctp-init_0.2.27-0_all.deb

The sctp-init package contains the init scripts and provides the postinst scripts necessary to create kernel module preloads and modules definitions for all kernel module ‘core’ subpackages.

sctp-source_0.2.27-0_all.deb

The sctp-source package contains the source code necessary for building the OpenSS7 Linux Native SCTP release. It includes the autoconf(1) configuration utilities necessary to create and distribute tarballs, rpms and deb/dscs. ²⁸

Architecture Dependent

sctp-devel_0.2.27-0_i386.deb

The sctp-devel package contains library archives for static compilation, header files to develop OpenSS7 Linux Native SCTP modules and drivers. This also includes the header files and static libraries required to compile OpenSS7 Linux Native SCTP applications programs.

sctp-lib_0.2.27-0_i386.deb

The sctp-lib package contains the run-time shared libraries necessary to run application programs and utilities developed for the SCTP package. ²⁹

STREAMS-Dependent DEB

STREAMS-Dependent DEB are dependent upon the specific STREAMS package being used, either Linux STREAMS or Linux Fast-STREAMS. Packages dependent upon Linux STREAMS will have LiS in the package name. Packages dependent upon Linux Fast-STREAMS will have streams in the package name. Note that some STREAMS-Dependent DEB are also Kernel-Dependent DEB as described below.

One of the following STREAMS-Dependent packages is required for your architecture. If your architecture is not on the list, you can build binary DEB from the Debian DSC (see see Building from the Debian DSC).

sctp-LiS-util_0.2.27-0_i386.deb

The sctp-LiS-util package provides administrative and configuration test utilities and commands associated with the OpenSS7 Linux Native SCTP package. Because this package must link a STREAMS-specific library, it is a STREAMS-Dependent package. Use the sctp-LiS-util package if you have LiS installed.

sctp-streams-util_0.2.27-0_i386.deb

The sctp-streams-util package provides administrative and configuration test utilities and commands associated with the OpenSS7 Linux Native SCTP package. Because this package must link a STREAMS-specific library, it is a STREAMS-Dependent package. Use the sctp-streams-util package if you have streams installed.

Kernel-Dependent DEB

Kernel-Dependent DEB are dependent on specific Linux Kernel Binary DEB releases. Packages are provided for popular released Debian kernels. Packages dependent upon Debian or other kernel DEB will have the ‘_kversion’ kernel package version in the package name.

One of the following Kernel-Dependent packages is required for your architecture and kernel version. If your architecture or kernel version is not on the list, you can build binary DEB from the source DEB (see see Building from the Debian DSC).³⁰

sctp-core-2.4.20-28.7_0.2.27-0_i386.deb

The sctp-core package contains the loadable kernel modules that depend only on the kernel. This package is heavily tied to the kernel for which it was compiled. This particular package applies to kernel version ‘2.4.20-28.7’.³¹

sctp-info-2.4.20-28.7_0.2.27-0_i386.deb

The sctp-info package³² contains the module symbol version information for the core subpackage, above. It is possible to load this subpackage and compile modules that use the exported symbols without loading the actual kernel modules (from the core subpackage above). This package is heavily tied to the kernel for which it was compiled. This particular package applies to kernel version ‘2.4.20-28.7’.³³

sctp-LiS-core-2.4.20-28.7_0.2.27-0_i386.deb

The sctp-LiS-core package contains the kernel modules that provide the OpenSS7 Linux Native SCTP STREAMS modules and drivers. This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to LiS (Linux STREAMS) on kernel version ‘2.4.20-28.7’.³⁴

sctp-streams-core-2.4.20-28.7_0.2.27-0_i386.deb

The sctp-streams-core package contains the kernel modules that provide the OpenSS7 Linux Native SCTP STREAMS modules and drivers. This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to streams (Linux Fast-STREAMS) on kernel version ‘2.4.20-28.7’.³⁵

sctp-LiS-info-2.4.20-28.7_0.2.27-0_i386.deb

The sctp-LiS-info package³⁶ contains the module symbol version information for the LiS-core subpackage, above. It is possible to load this subpackage and compile modules that use the exported symbols without loaded the actual kernel modules (from the LiS-core subpackage above). This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to LiS (Linux STREAMS) on kernel version ‘2.4.20-28.7’.³⁷

sctp-streams-info-2.4.20-28.7_0.2.27-0_i386.deb

The sctp-streams-info package³⁸ contains the module symbol version information for the streams-core subpackage, above. It is possible to load this subpackage and compile modules that use the exported symbols without loaded the actual kernel modules (from the streams-core subpackage above). This package is heavily tied to the STREAMS package and kernel for which it was compiled. This particular package applies to streams (Linux Fast-STREAMS) on kernel version ‘2.4.20-28.7’.³⁹

Configuration and Installation

To configure, build and install the Debian DEB, See Configuring the Debian DEB.

6.2.5 Downloading the Source RPM

If you cannot obtain a binary RPM for your architecture, or would like to roll you own binary RPM, download the following source RPM.

sctp-0.2.27-1.src.rpm

This is the source RPM for the package. From this source RPM it is possible to build binary RPM for any supported architecture and for any 2.4 or 2.6 kernel, for either Linux STREAMS or Linux Fast-STREAMS.

Configuration

To configure the source RPM, See Configuring the Source RPM.

6.2.6 Downloading the Debian DSC

If you cannot obtain a binary DEB for your architecture, or would like to roll your own DEB, download the following Debian DSC.

sctp_0.2.27-0.dsc

sctp_0.2.27-0.tar.gz

This is the Debian DSC for the package. From this Debian DSC it is possible to build binary DEB for any supported architecture and for any 2.4 or 2.6 kernel, for either Linux STREAMS or Linux Fast-STREAMS.

Configuration

To configure the source RPM, See Configuring the Debian DSC.

6.2.7 Downloading the Tar Ball

For non-rpm(1) and non-dpkg(1) architectures, download the tarball as follows:

sctp-0.2.27.tar.gz

sctp-0.2.27.tar.bz2

These are the tar(1) balls for the release. These tar(1) balls contain the autoconf(1) distribution which includes all the source necessary for building and installing the package. These tarballs will even build Source RPM and Binary RPM on rpm(1) architectures and Debian DSC and DEB on dpkg(1) architectures.

The tar ball may be downloaded easily with wget(1) as follows:

     % wget http://www.openss7.org/sctp-0.2.27.tar.bz2

or

     % wget http://www.openss7.org/sctp-0.2.27.tar.gz

Note that you will need an OpenSS7 Project user name and password to download release candidates (which are only available to subscribers and sponsors of the OpenSS7 Project).

Unpacking the Archive

After downloading one of the tar balls, unpack the archive using one of the following commands:

     % wget http://www.openss7.org/sctp-0.2.27.tar.gz
     % tar -xzvf sctp-0.2.27.tar.gz

or

     % wget http://www.openss7.org/sctp-0.2.27.tar.bz2
     % tar -xjvf sctp-0.2.27.tar.bz2

Either will create a subdirectory name sctp-0.2.27 containing all of the files and subdirectories for the SCTP package.

Configuration

To configure and install the tar ball, See Configuring the Tar Ball.

6.2.8 Downloading from CVS

If you are a subscriber or sponsor of The OpenSS7 Project with CVS archive access privileges then you can download release, mid-release or release candidate versions of the SCTP package from the project CVS archive.

The OpenSS7 Linux Native SCTP package is located in the sctp module of /var/cvs. For release tag information, see Releases.

To access the archive from the project CVS pserver, use the following commands to check out a version from the archive:

     % export CVSROOT='-d:pserver:username@cvs.openss7.com:2401/var/cvs'
     % cvs login
     Password: *********
     % cvs co -r sctp_0.2.27 sctp
     % cvs logout

It is, of course, possible to check out by date or by other criteria. For more information, see cvs(1).

Preparing the CVS Working Directory

Although public releases of the SCTP package do not require reconfiguration, creating a configurable directory from the CVS archive requires tools not normally distributed with the other releases.

The build host requires the following GNU tools:

• m4 1.4.12
• autoconf 2.63
• automake 1.10.1
• libtool 2.2.4
• gettext 0.17
• flex 2.5.33
• bison 2.3

Most desktop development GNU/Linux distributions wil have these tools; however, some non-development or server-style installations might not and they must be installed separately.⁴⁰

Also, these tools can be acquired from the FSF website in the free software directory, and also at the following locations:

• m4-1.4.12
• autoconf-2.63
• automake-1.10.1
• libtool-2.2.4
• gettext-0.17
• flex-2.5.33
• bison-2.3

It should be stressed that, in particular, the autoconf(1), and automake(1), must be at version releases 2.63 and 1.10.1. The versions normally distributed in some mainstream GNU/Linux distributions are, in fact, much older than these versions.⁴¹ GNU version of these packages configured and installed to default directories will install in /usr/local/ allowing them to coexist with distribution installed versions.

For building documentation, the build host also requires the following documentation tools:

• gs 6.51 or ghostscript 6.51, or newer.
• tetex 3.0 or texlive 2007, or newer.
• texinfo 4.13a or newer.
• transfig 3.2.3d or newer.
• imagemagick 5.3.8 or ImageMagick 5.3.8, or newer.
• groff 1.17.2 or newer.
• gnuplot 3.7 or newer.
• latex2html 1.62 or newer.

Most desktop GNU/Linux distributions will have these tools; however, some server-style installations (e.g. Ubuntu-server, SLES 9 or Fedora 6 or 7) will not and they must be installed separately.⁴²

Note that texinfo 4.12 must not be used as it breaks the build process.

For uncooked manual pages, the entire groff(1) package is required on older Debian and Ubuntu systems (the base package did not include grefer(1) which is used extensively by uncooked manual pages). The following will get what you need on older systems:

     Debian: % apt-get install groff_ext
     Ubuntu: % apt-get install groff

On newer systems, simply:

     % apt-get install groff

In addition, the build host requires a complete tool chain for compiling for the target host, including kernel tools such as genksyms(8) and others.

If you wish to package rpms on an rpm(1) system, or debs on a dpkg(1) system, you will need the appropriate tool chain. Systems based on rpm(1) typically have the necessary tool chain available, however, dpkg(1) systems do not. The following on a Debian or Ubuntu system will get what you need:

     % apt-get install debhelper
     % apt-get install fakeroot

To generate a configuration script and the necessary scriptlets required by the GNU autoconf(1) system, execute the following commands on the working directory:

     % autoreconf -fiv sctp

where, sctp is the name of the directory to where the working copy was checked out under the previous step. This command generates the configure script and other missing pieces that are normally distributed with the release Tar Balls, SRPMs and DSCs.

Make sure that ‘autoreconf --version’ returns ‘2.63’. Otherwise, you may need to perform something like the following:

     % PATH="/usr/local/bin:$PATH"
     % autoreconf -fiv sctp

After reconfiguring the directory, the package can then be configured and built using the same instructions as are used for the Tar Ball, see Configuring the Tar Ball, and Building from the Tar Ball.

Do note, however, that make(1) will rebuild the documentation that is normally released with the package. Additional tools may be necessary for building the documentation. To avoid building and installing the documentation, use the --disable-devel or --disable-docs option to configure described in Configuring the Tar Ball.

When configuring the package in a working directory and while working a change-compile-test cycle that involves configuration macros or documentation, I find it of great advantage to invoke the GNU configure options --enable-maintainer-mode, --enable-dependency-tracking and --disable-devel. The first of these three options will add maintainer-specific targets to any generated Makefile, the second option will invoke automatic dependency tracking within the Makefile so rebuilds after changes to macro, source or documentation files will be automatically rebuilt; and the last option will suppress rebuilding and reinstalling documentation manual pages and header files. Header files will still be available under the /usr/src directory.

6.3 Configuration

6.3.1 Configuring the Binary RPM

In general the binary RPM do not require any configuration, however, during installation it is possible to relocate some of the installation directories. This allows some degree of customization. Relocations that are available on the binary RPM are as follows:

sctp-LiS-core-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

sctp-streams-core-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

/lib/modules/2.4.20-28.7

This relocatable directory contains the kernel modules that provide the SCTP STREAMS core, drivers and modules.⁴³

sctp-LiS-info-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

sctp-streams-info-2.4.20-28.7-0.2.27-1.7.2.i686.rpm

/usr/include/sctp/2.4.20-28.7

This relocatable directory contains the kernel module exported symbol information that allows other kernel modules to be compiled against the correct version of the sctp package.⁴⁴

sctp-dev-0.2.27-1.7.2.i686.rpm

(not relocatable)

sctp-devel-0.2.27-1.7.2.i686.rpm

/usr/lib

This relocatable directory contains sctp libraries.

/usr/include/sctp

This relocatable directory contains sctp header files.

sctp-doc-0.2.27-1.7.2.i686.rpm

/usr/share/doc

This relocatable directory contains all package specific documentation (including this manual). The subdirectory in this directory is the sctp-0.2.27 directory.

/usr/share/info

This relocatable directory contains info files (including the info version of this manual).

/usr/share/man

This relocatable directory contains manual pages.

sctp-LiS-lib-0.2.27-1.7.2.i686.rpm

sctp-streams-lib-0.2.27-1.7.2.i686.rpm

/usr/lib

This relocatable directory contains the run-time shared libraries necessary to run applications programs and utilities developed for OpenSS7 Linux Native SCTP.

/usr/share/locale

This relocatable directory contains the locale information for shared library files.

sctp-source-0.2.27-1.7.2.i686.rpm

/usr/src

This relocatable directory contains the source code.

sctp-LiS-util-0.2.27-1.7.2.i686.rpm

sctp-streams-util-0.2.27-1.7.2.i686.rpm

/usr/bin

This relocatable directory contains binary programs and utilities.

/usr/sbin

This relocatable directory contains system binary programs and utilities.

/usr/libexec

This relocatable directory contains test programs.

/etc

This relocatable directory contains init scripts and configuration information.

Installation

To install the binary RPM, See Installing the Binary RPM.

6.3.2 Configuring the Debian DEB

In general the binary DEB do not require any configuration.

Installation

To install the Debian DEB, See Installing the Debian DEB.

6.3.3 Configuring the Source RPM

When building from the source RPM (see Building from the Source RPM), the rebuild process uses a number of macros from the user's .rpmmacros file as described in rpm(8).

Following is an example of the ~/.rpmmacros file that I use for rebuilding RPMS:

     #
     # RPM macros for building rpms
     #
     
     %vendor OpenSS7 Corporation
     %distribution OpenSS7
     %disturl http://www.openss7.org/
     %packager Brian Bidulock <bidulock@openss7.org>
     %url http://www.openss7.org/
     
     %_signature gpg
     %_gpg_path /home/brian/.gnupg
     %_gpg_name openss7@openss7.org
     %_gpgbin /usr/bin/gpg
     
     %_source_payload w9.bzdio
     %_binary_payload w9.bzdio
     
     %_unpackaged_files_terminate_build 1
     %_missing_doc_files_terminate_build 1
     %_use_internal_dependency_generator 0
     %_repackage_all_erasures 0
     %_rollback_transaction_on_failure 0
     
     %configure2_5x %configure
     %make make
     

When building from the source RPM (see Building from the Source RPM), it is possible to pass a number of additional configuration options to the rpmbuild(1) process.

The additional configuration options are described below.

Note that distributions that use older versions of rpm do not have the --with or --without options defined. To achieve the same effect as:

     --with someparm=somearg

do:

     --define "_with_someparm --with-someparm=somearg"

This is a generic description of common rpmbuild(1) options. Not all rpmbuild(1) options are applicable to all SRPMs. Options that are kernel module specific are only applicable to SRPMs that build kernel modules. STREAMS options are only applicable to SRPMs that provide or require STREAMS.

--define "_kversion $PACKAGE_KVERSION"

Specifies the kernel version other than the running kernel for which to build. If _kversion is not defined when rebuilding, the environment variable PACKAGE_KVERSION is used. If the environment variable PACKAGE_KVERSION is not defined, then the version of the running kernel (i.e. discovered with ‘uname -r’) is used as the target version for kernel-dependent packages. This option can also be defined in an .rpmspec file using the macro name ‘_kversion’.

--with checks

--without checks

Enable or disable preinstall checks. Each packages supports a number of preinstall checks that can be performed by invoking the ‘check’ target with automake(1). These currently consist of checking each kernel module for unresolved kernel symbols, checking for documentation for exported kernel module symbols, checking for documentation for exported library symbols, checking for standard options for build and installable programs, checking for documentation for built and installable programs. Normally these checks are only run in maintainer mode, but can be enabled and disabled with this option.

--with k-optimize=HOW

--without k-optimize

Specify ‘HOW’ optimization, normal, size, speed or quick. size compiles kernel modules -Os, speed compiles kernel modules -O3, and quick compiles kernel modules -O0. The default is normal. Use with care.

--with cooked-manpages

--without cooked-manpages

Some systems do not like grefer(1) references in manual pages.⁴⁵ This option will cook soelim(1), refer(1), tbl(1) and pic(1) commands from the manual pages and also strip groff(1) comments. The default is to leave manual pages uncooked: they are actually smaller that way.

--with public

--without public

Release public packages or private packages. This option has no effect on the SCTP package. The default is to release public packages.

--with k-debug

--without k-debug

Specifies whether kernel debugging is to be performed on the build kernel modules. Mutually exclusive with test and safe below. This has the effect of removing static and inline attributes from functions and invoking all debugging macros in the code. The default is to not perform kernel debugging.

--with k-test

--without k-test

Specifies whether kernel testing is to be performed. Mutually exclusive with debug above and safe below. This has the effect of removing static and inline attributes from functions and invoking most debugging macros in the code. The default is to not perform kernel testing.

--with k-safe

--without k-safe

Specifies whether kernel saftey is to be performed. Mutually exclusive with debug and test above. This has the effect of invoking some more pedantic assertion macros in the code. The default is not to apply kernel safety.

--with k-inline

--without k-inline

Specifies whether kernel inline functions are to be placed inline. This has the effect of adding the -finline-functions flag to CFLAGS for compiling kernel modules. Linux 2.4 kernels are normally compiled -O2 which does not respect the inline directive. This compiles kernel modules with -finline-functions to get closer to -O3 optimization. For better optimization controls, See Configuring the Tar Ball.

--with k-modversions

--without k-modversions

Specifies whether kernel symbol versions are to be applied to symbols exported by package kernel modules. The default is to version exported module symbols. This package does not export symbols so this option has no effect.

--with devfs

--without devfs

Specifies whether the build is for a device file system daemon enabled system with autoloading, or not. The default is to build for devfsd(1) autoloading when CONFIG_DEVFS_FS is defined in the target kernel. The ‘rebuild’ target uses this option to signal to the RPM spec file that the ‘dev’ subpackage need not be built. This option does not appear when the package has no devices.

--with devel

--without devel

Specifies whether to build development environment packages such as those that include header files, static libraries, manual pages and texinfo(1) documentation. The default is to build development environment packages. This option can be useful when building for an embedded target where only the runtime components are desired.

--with docs

--without docs

Specifies whether to build and install major documentation such manual pages and texinfo(1) documentation. The default is to build and install documentation. This option can be useful when building for an embedded target where only the runtime and static compile components are desired, but not major documentation. This option does not override the setting of --without devel.

--with tools

--without tools

Specifies whether user space packages are to be built. The default is to build user space packages. This option can be useful when rebuilding for multiple architectures and target kernels. The ‘rebuild’ automake(1) target uses this feature when rebuilding for all available architectures and kernels, to rebuild user packages once per architecture instead of once per kernel.

--with modules

--without modules

Specifies whether kernel modules packages are to be built. The default is to build kernel module packages. This option can be useful when rebuilding for multiple architectures and target kernels. The ‘rebuild’ automake(1) target uses this feature to rebuild for all available architectures and kernels.

--with lis

--without lis

Specifies that the package is to be rebuilt against Linux STREAMS. The default is to automatically identify whether LiS or streams is loaded on the build system and build accordingly.

--with lfs

--without lfs

Specifies that the package is to be rebuilt against Linux Fast-STREAMS. The default is to automatically identify whether LiS or streams is loaded on the build system and build accordingly.

In addition, the following rpm options, specific to the OpenSS7 Linux Native SCTP package are available:

--with sctp-slow-verification

Enable slow verification of addresses and tags. When a message comes from an SCTP endpoint with the correct verification tag, it is not necessary to check whether it is from a correct source address to identify the SCTP association to which it belongs. When you disable this feature (--without sctp-slow-verification), source addresses are not checked and it is up to firewall implementations to thwart attackers of the verification tag. When you enable this feature (--enablesctp-slow-verification), you get RFC 2960 compliant operation, but at great cost to SCTP performance. This option defaults to ‘disabled’.

--with sctp-throttle-heartbeats

Enable heartbeat throttling. Special feature of OpenSS7 Linux Native SCTP that is not mentioned in RFC 2960. When you enable this feature (--with sctp-throttle-heartbeats), OpenSS7 Linux Native SCTP will throttle the rate at which it responds to heartbeats to the system control heartbeat_interval. This makes SCTP more resilient to implementations which flood heartbeat messages. For RFC 2960 compliant operation, disable this feature (--without sctp-throttle-heartbeats). This option defaults to ‘disabled’.

--with sctp-discard-ootb

Enable discard of out-of-the-blue packets. RFC 2960 requires the implementation to send ABORT to some OOTB packets (packets for which no SCTP association exists). Sending ABORT chunks to unverified source addresses with the T bit set opens SCTP to blind masquerade attacks. Not sending them may lead to delays at the peer endpoint aborting associations where our ABORT has been lost and the socket is already closed or if we have restarted and the peer still has open associations to us. If you enable this feature (--with sctp-discard-ootb), SCTP will discard all OOTB packets. This is necessary if another SCTP stack is being run on the same machine. Therefore, if the OpenSS7 Linux Native SCTP package is included on an OpenSS7 SCTP kernel, this feature is automatically enabled. For RFC 2960 compliant operation, disable this feature (--without sctp-discard-ootb). This option defaults to ‘disabled’ for non-OpenSS7 SCTP kernels, and ‘enabled’ for OpenSS7 SCTP kernels.

--with sctp-extended-ip-support

Enable extended IP support for SCTP. This provides extended IP support for SCTP for things like IP Transparent Proxy and IP Masquerading. This is experimental stuff. If in doubt, disable this feature (--without sctp-expended-ip-support). This option defaults to ‘disabled’.

--with sctp-hmac-sha1

Disable SHA-1 HMAC. This provides the ability to use the FIPS 180-1 (SHA-1) message authentication code in SCTP cookies. If you enable this feature (--with sctp-hmac-sha1), when the appropriate sysctl is set, SCTP will use the SHA-1 HMAC when signing cookies in the INIT-ACK chunk. If disable this feature (--without sctp-hmac-sha1), the SHA-1 HMAC will be unavailable for use with SCTP. This option defaults to ‘enabled’.

--with sctp-hmac-md5

Disable MD5 HMAC. This provides the ability to use the MD5 (RFC 1321) message authentication code in SCTP cookies. If you enable this feature (--with sctp-hmac-md5), when the appropriate sysctl is set, SCTP will use the MD5 HMAC when signing cookies in the INIT ACK chunk. If you disable this feature (--without sctp-hmac-md5), the MD5 HMAC will be unavailable for use with SCTP. This option defaults to ‘enabled’.

--with sctp-adler32

Enable Adler32 checksum. This provides the ability to use the older RFC 2960 Adler32 checksum. If CONFIG_SCTP_CRC_32 below is not selected, the Adler32 checksum is always provided. This option defaults to ‘disabled’.

--without sctp-crc32c

Disable CRC-32C checksum. This provides the ability to use the newer CRC-32c checksum as described in RFC 3309. When this is selected and CONFIG_SCTP_ADLER_32 is not selected above, then the only checksum that will be used is the CRC-32c checksum. This option defaults to ‘enabled’.

--with sctp-throttle-passiveopens

Enable throttling of passive opens. Special feature of Linux SCTP not mentioned in RFC 2960. When secure algorithms are used for signing cookies, the implementation becomes vulnerable to INIT and COOKIE-ECHO flooding. If you enable this feature (--with sctp-throttle-passiveopens), SCTP will only allow one INIT and one COOKIE-ECHO to be processed in each interval corresponding to the sysctl sctp_throttle_itvl. Setting sctp_throttle_itvl to 0 defeats this function. If you disable this feature (--without sctp-throttle-passiveopens), each INIT and COOKIE-ECHO will be processed. This option defaults to ‘disabled’.

--with sctp-ecn

Enable explicit congestion notification. This enables support for Explicit Congestion Notification (ECN) chunks in SCTP messages as defined in RFC 2960 and RFC 3168. It also adds syctl (/proc/net/ipv4/sctp_ecn) which allows ECN for SCTP to be disabled at runtime. This option defaults to ‘disabled’.

--with sctp-lifetimes

Enable SCTP message lifetimes. This enables support for message lifetimes as described in RFC 2960. When enabled, message lifetimes can be set on messages. See sctp(7). This feature is always enabled when Partial Reliability Support is set. This option defaults to ‘disabled’.

--with sctp-add-ip

Enable ADD-IP. This enables support for ADD-IP as described in draft-ietf-tsvwg-addip-sctp-07.txt. This allows the addition and removal of IP addresses from existing connections. This is experimental stuff. This option defaults to ‘disabled’.

--with sctp-adaptation-layer-info

Enable ALI. This enables support for the Adaptation Layer Information parameter described in draft-ietf-tsvwg-addip-sctp-07.txt for communicating application layer information bits at initialization. This is experimental stuff. This option defaults to ‘disabled’.

--with sctp-partial-reliability

Enable SCTP Partial Reliability (PR-SCTP). This enables support for PR-SCTP as described in draft-stewart-tsvwg-prsctp-03.txt. This allows for partial reliability of message delivery on a "timed reliability" basis. This is experimental stuff. This option defaults to ‘disabled’.

--without sctp-error-generator

Disable the SCTP error generator. This provides an internal error generator that can be accessed with socket options for testing SCTP operation under packet loss. You will need this option to run some of the test programs distributed with the SCTP module. This option defaults to ‘enabled’.

--without tcp-compatible

Disables support for SOCK_STREAM type TCP compatible sockets in addition to the normal SCTP SOCK_SEQPACKET sockets. These work well and are normally enabled. This option defaults to ‘enabled’.

--with udp-compatible

Enables support for SOCK_RDM type RUDP compatible sockets in addition to the normal SCTP SOCK_SEQPACKET sockets. These have not been tested. This is experimental stuff. This option defaults to ‘disabled’.

In general, the default values of these options are sufficient for most purposes and no options need be provided when rebuilding the Source RPMs.

Build

To build from the source RPM, See Building from the Source RPM.

6.3.4 Configuring the Debian DSC

The Debian DSC can be configured by passing options in the environment variable BUILD_DEBOPTIONS. The options placed in this variable take the same form as those passed to the configure script, See Configuring the Tar Ball. For an example, See Building from the Debian DSC.

Build

To build from the Debian DSC, See Building from the Debian DSC.

6.3.5 Configuring the Tar Ball

All of the normal GNU autoconf(1) configuration options and environment variables apply. Additional options and environment variables are provided to tailor or customize the build and are described below.

6.3.5.1 Configure Options

This is a generic description of common configure options that are in addition to those provided by autoconf(1), automake(1), libtool(1) and gettext(1).

Not all configure options are applicable to all release packages. Options that are kernel module specific are only applicable to release packages that build kernel modules. STREAMS options are only applicable to release packages that provide or require STREAMS.

Following are the additional configure options, their meaning and use:

--enable-checks

--disable-checks

Enable or disable preinstall checks. Each release package supports a number of preinstall checks that can be performed by invoking the ‘check’ target with make(1). These currently consist of checking each kernel module for unresolved kernel symbols, checking for documentation for exported kernel module symbols, checking for documentation for exported library symbols, checking for standard options for build and installable programs, checking for documentation for built and installable programs. Normally these checks are only run in maintainer mode, but can be enabled and disabled with this option.

--enable-autotest

--disable-autotest

Enable or disable pre- and post-installation testing. Each release package supports a number of autotest test suites that can be performed by invoking the ‘installcheck’ target with make(1). These currently consist of running installed modules, commands and binaries against a number of specific test cases. Normally these checks are only run in maintainer mode, but can be enabled and disabled with this option.

--disable-compress-manpages

Compress manual pages with ‘gzip -9’ or ‘bzip2 -9’ or leave them uncompressed. The default is to compress manual pages with ‘gzip -9’ or ‘bzip2 -9’ if a single compressed manual page exists in the target installation directory (--mandir). This disables automatic compression.

--disable-public

Disable public release. This option is not usable on public releases and only has a usable effect on OpenSS7 Linux Native SCTP when the package is acquired from CVS. In particular, the STREAMS SS7/VoIP/ISDN/SIGTRAN Stacks (strss7-0.9a.8) release package has a large number of non-public components. Specifying this option will cause the package to build and install all private release components in addition to the public release components. This option affects all release packages. Most release packages do not have private release components.

--disable-initscripts

Disables the installation of init scripts. The default is to configure and install init scripts and their associated configuration files.

Although the default is to install init scripts, installation attempts to detect a System V init script configuration, and if one is not found, the init scripts are installed into the appropriate directories, but the symbolic links to the run level script directories are not generated and the script is not invoked. Therefore, it is safe to leave this option unchanged, even on distributions that do not support System V init script layout.

--disable-32bit-libs

Disables the build and install of 32-bit compatibility libraries and test binaries on 64-bit systems that support 32-bit compatibility. The default is to build and install 32-bit compatibility libraries and test binaries. This option can be usefule when configuring for an embedded target where only native shared libraries and binaries are desired.

--disable-devel

Disables the installation of development environment components such as header files, static libraries, manual pages and texinfo(1) documentation. The default is to install development environment components. This option can be useful when configuring for an embedded target where only the runtime components are desired, or when performing a edit-compile-test cycle.

--disable-docs

Disables the build and installation of major documentation such manual pages and texinfo(1) documentation. The default is to build and install documentation. This option can be useful when building for an embedded target where only the runtime and static compile components are desired, but not major documentation. This option does not override the setting of --disable-devel.

--enable-tools

Specifies whether user space programs and libraries are to be built and installed. The default is to build and install user space programs and libraries. This option can be useful when rebuilding for multiple architectures and target kernels, particularly under rpm(1) or dpkg(1). The ‘rebuild’ automake(1) target uses this feature when rebuilding RPMs for all available architectures and kernels, to rebuild user packages once per architecture instead of once per kernel.

--enable-modules

Specifies whether kernel modules are to be built and installed. The default is to build and install kernel modules. This option can be useful when rebuilding for multiple architectures and target kernels, particularly under rpm(1) or dpkg(1). The ‘rebuild’ automake(1) target uses this feature to rebuild for all available architectures and kernels. This option has no effect for release packages that do not provide kernel modules.

--enable-arch

Specifies whether architectural dependent package components are to be built and installed. This option can be useful when rebuilding for multiple architectures and target kernels, particularly under dpkg(1). The default is to configure, build and install architecture dependent package components. This option has no effect for release packages that do not provide architecture dependent components.

--enable-indep

Specifies whether architecture independent package components are to be built and installed. This option can be useful when rebuilding for multiple architectures and target kernels, particularly under dpkg(1). The default is to configure, build and install architecture independent package components. This options has no effect for release packages that do not provide architecture independent components.

--enable-k-inline

Enable kernel inline functions. Most Linux kernels build without -finline-functions. This option adds the -finline-functions and -Winline flags to the compilation of kernel modules. Use with care. This option has no effect for release packages that do not provide kernel modules.

--enable-k-safe

Enable kernel module run-time safety checks. Specifies whether kernel safety is to be performed. This option is mutually exclusive with --enable-k-test and --enable-k-debug below. This has the effect of invoking some more pedantic assertion macros in the code. The default is not to apply kernel safety. This option has no effect for release packages that have are no kernel modules.

--enable-k-test

Enable kernel module run-time testing. Specifies whether kernel testing is to be performed. This option is mutually exclusive with --enable-k-safe above and --enable-k-debug below. This has the effect of remove static and inline attributes from functions and invoking most non-performance affecting debugging macros in the code. The default is not to perform kernel testing. This option has no effect for release packages that do not provide kernel modules.

--enable-k-debug

Enable kernel module run-time debugging. Specifies whether kernel debugging is to be performed. This option is mutually exclusive with --enable-k-safe and --enable-k-test above. This has the effect of removing static and inline attributes from functions and invoking all debugging macros in the code (including performance-affecting debug macros). The default is to not perform kernel debugging. This option has no effect for release packages that do not provide kernel modules.

--disable-k-modversions

Disable module versions on SCTP symbols. Specifies whether kernel symbol versions are to be used on symbols exported from built SCTP modules. The default is to provide kernel symbol versions on all exported symbols. This option has no effect for release packages that do not provide kernel modules.

--enable-devfs

--disable-devfs

Specifies whether the build is for a device file system daemon enabled system with autoloading, or not. The default is to build for devfsd(8) autoloading when CONFIG_DEVFS_FS is defined in the target kernel. The ‘reuild’ automake(1) target uses this option to signal to the RPM spec file that the ‘dev’ subpackage need not be built. This option has no effect for release packages that do not provide devices.

--with-gpg-user=GNUPGUSER

Specify the gpg(1) ‘GNUPGUSER’ for signing RPMs and tarballs. The default is the content of the environment variable GNUPGUSER. If unspecified, the gpg(1) program will normally use the user name of the account invoking the gpg(1) program. For building source RPMs, the RPM macro ‘_gpg_name’ will override this setting.

--with-gpg-home=GNUPGHOME

Specify the ‘GNUPGHOME’ directory for signing RPMs and tarballs. The default is the user's ~/.gpg directory. For building source RPMs, the RPM macro ‘_gpg_path’ will override this setting.

--with-pkg-epoch=EPOCH

Specifies the epoch for the package. This is neither used for rpm(1) nor dpkg(1) packages, it applies to the tarball release as a whole. The default is the contents of the .pkgepoch file in the release package source directory or, if that file does not exist, zero (0).

--with-pkg-release=RELEASE

Specifies the release for the package. This is neither used for rpm(1) nor dpkg(1) packages, it applies to the tarball release as a whole. The default is the contents of the .pkgrelease file in the release package source directory or, if that file does not exist, one (1). This is the number after the last point in the package version number.

--with-pkg-distdir=DIR

Specifies the distribution directory for the package. This is used by the maintainer for building distributions of tarballs. This is the directory into which archives are copied for distribution. The default is the top build directory.

--with-cooked-manpages

Convert manual pages to remove macro dependencies and grefer(1) references. Some systems do not like grefer(1) references in manual pages.⁴⁶ This option will cook soelim(1), refer(1), tbl(1) and pic(1) commands from the manual pages and also strip groff(1) comments. The default is to leave manual pages uncooked (they are actually smaller that way).

--with-rpm-epoch=PACKAGE_EPOCH

Specify the ‘PACKAGE_EPOCH’ for the RPM spec file. The default is to use the RPM epoch contained in the release package file .rpmepoch.

--with-rpm-release=PACKAGE_RPMRELEASE

Specify the ‘PACKAGE_RPMRELEASE’ for the RPM spec file. The default is to use the RPM release contained in the release package file .rpmrelease.

--with-rpm-extra=PACKAGE_RPMEXTRA

Specify the ‘PACKAGE_RPMEXTRA’ extra release information for the RPM spec file. The default is to use the RPM extra release information contained in the release package file .rpmextra. Otherwise, this value will be determined from automatic detection of the RPM distribution.

--with-rpm-topdir=PACKAGE_RPMTOPDIR

Specify the ‘PACKAGE_RPMTOPDIR’ top directory for RPMs. If specified with a null ‘PACKAGE_RPMTOPDIR’, the default directory for the RPM distribution will be used. If this option is not provided on the command line, the top build directory will be used as the RPM top directory as well.

--with-deb-epoch=EPOCH

Specify the ‘PACKAGE_DEBEPOCH’ for the DEB control file. The default is to use the DEB epoch contained in the release package file .debepoch.

--with-deb-release=RELEASE

Specify the ‘PACKAGE_DEBRELEASE’ for the DEB control file. The default is to use the DEB release contained in the release package file .debrelease.

--with-deb-topdir=DIR

Specify the ‘PACKAGE_DEBTOPDIR’ top directory for DEBs. If specified with a null ‘PACKAGE_DEBTOPDIR’, the default directory for the DEB distribution will be used. If this option is not provided on the command line, the top build directory will be used as the DEB top directory as well.

--with-k-release=PACKAGE_KRELEASE

Specify the ‘PACKAGE_KRELEASE’ release of the Linux kernel for which the build is targeted. When not cross compiling, if this option is not set, the build will be targeted at the kernel running in the build environment (e.g., ‘uname -r’). When cross-compiling this option must be specified or the configure script will generate an error and terminate.

--with-k-linkage=PACKAGE_KLINKAGE

Specify the ‘PACKAGE_KLINKAGE’ for kernel module linkage. This can be one of the following:

• ‘loadable’ – loadable kernel modules
• ‘linkable’ – linkable kernel objects

The default is to build loadable kernel modules.

--with-k-modules=K-MODULES-DIR

Specify the ‘K-MODULES-DIR’ directory to which kernel modules will be installed. The default is based on the option --with-k-release, --with-k-prefix and --with-k-rootdir. The default is DESTDIR/K-MODULES-DIR which is typically DESTDIR/lib/modules/PACKAGE_KRELEASE/. This directory is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-build=K-BUILD-DIR

Specify the ‘K-BUILD-DIR’ base kernel build directory in which configured kernel source resides. The default is DESTDIR/K-MODULES-DIR/build. This directory is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-source=K-SOURCE-DIR

Specify the ‘K-SOURCE-DIR’ base kernel build directory in which configured kernel source resides. The default is DESTDIR/K-MODULES-DIR/source. This directory is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-modver=K-MODVER-FILE

Specify the ‘K-MODVER-FILE’ kernel module versions file. The default is K-BUILD-DIR/Module.symvers. This file is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-sysmap=K-SYSMAP-FILE

Specify the ‘K-SYSMAP-FILE’ kernel system map file. The default is K-BUILD-DIR/System.map. This file is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-archdir=K-ARCHDIR

Specify the ‘K-ARCHDIR’ kernel source architecture specific directory. The default is DESTDIR/K-SOURCE-DIR/arch. This directory is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-machdir=K-MACHDIR

Specify the ‘K-MACHDIR’ kernel source machine specific directory. The default is DESTDIR/K-SOURCE-DIR/target_cpu. This directory is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-config=K-CONFIG

Specify the ‘K-CONFIG’ kernel configuration file. The default is BOOT/config-K-RELEASE. This configuration file is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message.

--with-k-optimize=HOW

--without-k-optimize

Specify ‘HOW’ optimization, normal, size, speed or quick. size compiles kernel modules -Os, speed compiles kernel modules -O3, and quick compiles kernel modules -O0. The default is normal. Use with care. The most common use of this option is to specify --with-k-optimize=speed --disable-k-safe to compile for maximum performance. Nevertheless, even these setting are ricing and the resulting kernel modules will only be about 5% faster.

--with-lis[=LIS-DIR]

--without-lis

Specify the ‘LIS-DIR’ directory in which to find LiS headers. Also specifies that the build is to be made against Linux STREAMS. The default is /usr/include/LiS if it exists, ‘no’ otherwise. This directory is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message. This option has no effect on release packages that do not use the STREAMS subsystem.

--with-lfs[=LFS-DIR]

--without-lfs

Specify the ‘LFS-DIR’ directory in which to find LfS headers. Also specifies that the build is to be made against Linux Fast-STREAMS. The default is /usr/include/streams if it exists, ‘no’ otherwise. This directory is normally located by the configure script and need only be provided for special cross-build environments or when requested by a configure script error message. This option has no effect on release packages that do not use the STREAMS subsystem.

--with-strconf-master=STRCONF_CONFIG

Specify the ‘STRCONF_CONFIG’ file name to which the configuration master file is written. The default is Config.master. This option has no effect on release packages that do not use the STREAMS subsystem and the strconf scripts. This option should not be specified when configuring the master package as the setting for all add-on packages will conflict.

--with-base-major=STRCONF_MAJBASE

Start numbering for major devices at ‘STRCONF_MAJBASE’. The default is ‘230’. This option has no effect on release packages that do not use the STREAMS subsystem and the strconf scripts. This option should not be specified when configuring the master package as the setting for all add-on packages will conflict.

In addition, the following configure options, specific to the OpenSS7 Linux Native SCTP package are available:

--enable-sctp-slow-verification

Enable slow verification of addresses and tags. When a message comes from an SCTP endpoint with the correct verification tag, it is not necessary to check whether it is from a correct source address to identify the SCTP association to which it belongs. When you disable this feature (--disable-sctp-slow-verification), source addresses are not checked and it is up to firewall implementations to thwart attackers of the verification tag. When you enable this feature (--enablesctp-slow-verification), you get RFC 2960 compliant operation, but at great cost to SCTP performance. This option defaults to ‘disabled’.

--enable-sctp-throttle-heartbeats

Enable heartbeat throttling. Special feature of OpenSS7 Linux Native SCTP that is not mentioned in RFC 2960. When you enable this feature (--enable-sctp-throttle-heartbeats), OpenSS7 Linux Native SCTP will throttle the rate at which it responds to heartbeats to the system control heartbeat_interval. This makes SCTP more resilient to implementations which flood heartbeat messages. For RFC 2960 compliant operation, disable this feature (--disable-sctp-throttle-heartbeats). This option defaults to ‘disabled’.

--enable-sctp-discard-ootb

Enable discard of out-of-the-blue packets. RFC 2960 requires the implementation to send ABORT to some OOTB packets (packets for which no SCTP association exists). Sending ABORT chunks to unverified source addresses with the T bit set opens SCTP to blind masquerade attacks. Not sending them may lead to delays at the peer endpoint aborting associations where our ABORT has been lost and the socket is already closed or if we have restarted and the peer still has open associations to us. If you enable this feature (--enable-sctp-discard-ootb), SCTP will discard all OOTB packets. This is necessary if another SCTP stack is being run on the same machine. Therefore, if the OpenSS7 Linux Native SCTP package is included on an OpenSS7 SCTP kernel, this feature is automatically enabled. For RFC 2960 compliant operation, disable this feature (--disable-sctp-discard-ootb). This option defaults to ‘disabled’ for non-OpenSS7 SCTP kernels, and ‘enabled’ for OpenSS7 SCTP kernels.

--enable-sctp-extended-ip-support

Enable extended IP support for SCTP. This provides extended IP support for SCTP for things like IP Transparent Proxy and IP Masquerading. This is experimental stuff. If in doubt, disable this feature (--disable-sctp-expended-ip-support). This option defaults to ‘disabled’.

--enable-sctp-hmac-sha1

Disable SHA-1 HMAC. This provides the ability to use the FIPS 180-1 (SHA-1) message authentication code in SCTP cookies. If you enable this feature (--enable-sctp-hmac-sha1), when the appropriate sysctl is set, SCTP will use the SHA-1 HMAC when signing cookies in the INIT-ACK chunk. If disable this feature (--disable-sctp-hmac-sha1), the SHA-1 HMAC will be unavailable for use with SCTP. This option defaults to ‘enabled’.

--enable-sctp-hmac-md5

Disable MD5 HMAC. This provides the ability to use the MD5 (RFC 1321) message authentication code in SCTP cookies. If you enable this feature (--enable-sctp-hmac-md5), when the appropriate sysctl is set, SCTP will use the MD5 HMAC when signing cookies in the INIT ACK chunk. If you disable this feature (--disable-sctp-hmac-md5), the MD5 HMAC will be unavailable for use with SCTP. This option defaults to ‘enabled’.

--enable-sctp-adler32

Enable Adler32 checksum. This provides the ability to use the older RFC 2960 Adler32 checksum. If CONFIG_SCTP_CRC_32 below is not selected, the Adler32 checksum is always provided. This option defaults to ‘disabled’.

--disable-sctp-crc32c

Disable CRC-32C checksum. This provides the ability to use the newer CRC-32c checksum as described in RFC 3309. When this is selected and CONFIG_SCTP_ADLER_32 is not selected above, then the only checksum that will be used is the CRC-32c checksum. This option defaults to ‘enabled’.

--enable-sctp-throttle-passiveopens

Enable throttling of passive opens. Special feature of Linux SCTP not mentioned in RFC 2960. When secure algorithms are used for signing cookies, the implementation becomes vulnerable to INIT and COOKIE-ECHO flooding. If you enable this feature (--enable-sctp-throttle-passiveopens), SCTP will only allow one INIT and one COOKIE-ECHO to be processed in each interval corresponding to the sysctl sctp_throttle_itvl. Setting sctp_throttle_itvl to 0 defeats this function. If you disable this feature (--disable-sctp-throttle-passiveopens), each INIT and COOKIE-ECHO will be processed. This option defaults to ‘disabled’.

--enable-sctp-ecn

Enable explicit congestion notification. This enables support for Explicit Congestion Notification (ECN) chunks in SCTP messages as defined in RFC 2960 and RFC 3168. It also adds syctl (/proc/net/ipv4/sctp_ecn) which allows ECN for SCTP to be disabled at runtime. This option defaults to ‘disabled’.

--enable-sctp-lifetimes

Enable SCTP message lifetimes. This enables support for message lifetimes as described in RFC 2960. When enabled, message lifetimes can be set on messages. See sctp(7). This feature is always enabled when Partial Reliability Support is set. This option defaults to ‘disabled’.

--enable-sctp-add-ip

Enable ADD-IP. This enables support for ADD-IP as described in draft-ietf-tsvwg-addip-sctp-07.txt. This allows the addition and removal of IP addresses from existing connections. This is experimental stuff. This option defaults to ‘disabled’.

--enable-sctp-adaptation-layer-info

Enable ALI. This enables support for the Adaptation Layer Information parameter described in draft-ietf-tsvwg-addip-sctp-07.txt for communicating application layer information bits at initialization. This is experimental stuff. This option defaults to ‘disabled’.

--enable-sctp-partial-reliability

Enable SCTP Partial Reliability (PR-SCTP). This enables support for PR-SCTP as described in draft-stewart-tsvwg-prsctp-03.txt. This allows for partial reliability of message delivery on a "timed reliability" basis. This is experimental stuff. This option defaults to ‘disabled’.

--disable-sctp-error-generator

Disable the SCTP error generator. This provides an internal error generator that can be accessed with socket options for testing SCTP operation under packet loss. You will need this option to run some of the test programs distributed with the SCTP module. This option defaults to ‘enabled’.

--disable-tcp-compatible

Disables support for SOCK_STREAM type TCP compatible sockets in addition to the normal SCTP SOCK_SEQPACKET sockets. These work well and are normally enabled. This option defaults to ‘enabled’.

--enable-udp-compatible

Enables support for SOCK_RDM type RUDP compatible sockets in addition to the normal SCTP SOCK_SEQPACKET sockets. These have not been tested. This is experimental stuff. This option defaults to ‘disabled’.

6.3.5.2 Environment Variables

Following are additional environment variables to configure, their meaning and use:

GPG

GPG signature command. This is used for signing distributions by the maintainer. By default, configure will search for this tool.

GNUPGUSER

GPG user name. This is used for signing distributions by the maintainer.

GNUPGHOME

GPG home directory. This is used for signing distributions by the maintainer.

GPGPASSWD

GPG password for signing. This is used for signing distributions by the maintainer. This environment variable is not maintained by the configure script and should only be used on an isolated system.

SOELIM

Roff source elimination command, soelim(1). This is only necessary when the option --with-cooked-manpages has been specified and configure cannot find the proper soelim(1) command. By default, configure will search for this tool.

REFER

Roff references command, refer(1). This is only necessary when the option --with-cooked-manpages has been specified and configure cannot find the proper refer(1) command. By default, configure will search for this tool.

TBL

Roff table command, tbl(1). This is only necessary when the option --with-cooked-manpages has been specified and configure cannot find the proper tbl(1) command. By default, configure will search for this tool.

PIC

Roff picture command, pic(1). This is only necessary when the option --with-cooked-manpages has been specified and configure cannot find the proper pic(1) command. By default, configure will search for this tool.

GZIP

Default compression options provided to GZIP_CMD.

GZIP_CMD

Manpages (and kernel modules) compression commands, gzip(1). This is only necessary when the option --without-compressed-manpages has not been specified and configure cannot find the proper gzip(1) command. By default, configure will search for this tool.

BZIP2

Default compression options provided to BZIP2_CMD

BZIP2_CMD

Manpages compression commands, bzip2(1). This is only necessary when the option --without-compressed-manpages has not been specified and configure cannot find the proper bzip2(1) command. By default, configure will search for this tool.

MAKEWHATIS

Manpages apropros database rebuild command, makewhatis(8). By default, configure will search for this tool. By default, configure will search for this tool.

CHKCONFIG

Chkconfig command, chkconfig(8). This was used for installation of init scripts. All packages now come with init_install(8) and init_remove(8) scripts used to install and remove init scripts on both RPM and Debian systems.

RPM

Rpm command, rpm(1). This is only necessary for RPM builds. By default, configure will search for this tool.

RPMBUILD

Build RPM command, rpmbuild(1). This is only necessary for RPM builds. By default, configure will search for this tool. rpm(1) will be used instead of rpmbuild(1) only if rpmbuild(1) cannot be found.

DPKG

Dpkg comand, dpkg(1). This command is used for building Debian packages. By default, configure will search for this tool.

DPKG_SOURCE

Dpkg-source command, dpkg-source(1). This command is used for building Debian dsc packages. By default, configure will search for this tool.

DPKG_BUILDPACKAGE

Dpkg-buildpackage command, dpkg-buildpackage(1). This command is used for building Debian deb packages. By default, configure will search for this tool.

DEB_BUILD_ARCH

Debian build architecture. This variable is used for building Debian packages. The default is the autoconf build architecture.

DEB_BUILD_GNU_CPU

Debian build cpu. This variable is used for building Debian packages. The default is the autoconf build cpu.

DEB_BUILD_GNU_SYSTEM

Debian build os. This variable is used for building Debian packages. The default is the autoconf build os.

DEB_BUILD_GNU_TYPE

Debian build alias. This variable is used for building Debian packages. The default is the autoconf build alias.

DEB_HOST_ARCH

Debian host architecture. This variable is used for building Debian packages. The default is the autoconf host architecture.

DEB_HOST_GNU_CPU

Debian host cpu. This variable is used for building Debian packages. The default is the autoconf host cpu.

DEB_HOST_GNU_SYSTEM

Debian host os. This variable is used for building Debian packages. The default is the autoconf host os.

DEB_HOST_GNU_TYPE

Debian host alias. This variable is used for building Debian packages. The default is the autoconf host alias.

LDCONFIG

Configure loader command, ldconfig(8). Command used to configure the loader when libraries are installed. By default, configure will search for this tool.

DESTDIR

Cross build root directory. Specifies the root directory for build and installation.

DEPMOD

Build kernel module dependencies command, depmod(8). This is used during installation of kernel modules to a running kernel to rebuild the modules dependency database. By default, configure will search for this tool.

MODPROBE

Probe kernel module dependencies command, modprobe(8). This is used during installation of kernel modules to a running kernel to remove old modules. By default, configure will search for this tool.

LSMOD

List kernel modules command, lsmod(8). This is used during installation of kernel modules to a running kernel to detect old modules for removal. By default, configure will search for this tool.

LSOF

List open files command, lsof(1). This is used during installation of kernel modules to a running kernel to detect old modules for removal. Processes owning the old kernel modules will be killed and the module removed. If the process restarts, the new module will be demand loaded. By default, configure will search for this tool.

GENKSYMS

Generate kernel symbols command, genksyms(8). This is used for generating module symbol versions during build. By default, configure will search for this tool.

KGENKSYMS

Linux 2.6 generate kernel symbols command, genksyms(8). This is used for generating module symbol version during build. By default, configure will search for this tool.

OBJDUMP

Object dumping command, objdump(1). This is used for listing information about object files. By default, configure will search for this tool.

NM

Object symbol listing command, nm(1). This is used for listing information about object files. By default, configure will search for this tool.

MODPOST_CACHE

Cache file for modpost(1). The version of the modpost.sh script that ships with each package can cache information to a cache file to speed multiple builds. This environment variable is used to specify a cache file.

AUTOM4TE

Autom4te command, autom4te(1). This is the executable used by autotest for pre- and post-installation checks. By default, configure will search for this tool.

AUTOTEST

Autotest macro build command, autom4te(1). This is the executable used by autotest for pre- and post-installation checks. By default, configure will search for this tool.