Software
www.skarnet.org

s6-networking

What is it ?

s6-networking is a suite of small networking utilities for Unix systems. It includes command-line client and server management, TCP access control, privilege escalation across UNIX domain sockets, IDENT protocol management and clock synchronization. Optionally, it also includes command-line TLS/SSL tools for secure communications.

If the underlying skalibs has been compiled with IPv6 support, s6-networking is IPv6-ready.

Installation

Requirements

• A POSIX-compliant system with a standard C development environment
• GNU make, version 3.81 or later
• skalibs version 2.4.0.1 or later. It's a build-time requirement. It's also a run-time requirement if you link against the shared version of the skalibs library.
• execline version 2.2.0.0 or later. It's a build-time and run-time requirement.
• s6 version 2.4.0.0 or later. It's a build-time and run-time requirement.
• s6-dns version 2.1.0.0 or later. It's a build-time requirement. It's also a run-time requirement if you link against the shared version of the s6-dns libraries.
• If you want to build the TLS/SSL tools:
  • Either LibreSSL version 2.4.4 or later
  • Or BearSSL version 0.1 or later. THIS IS EXPERIMENTAL.
  The chosen library is a build-time requirement, and also a run-time requirement if you link against its shared version.

Licensing

s6-networking is free software. It is available under the ISC license.

Download

• The current released version of s6-networking is 2.2.1.0.
• Alternatively, you can checkout a copy of the s6-networking git repository:

   git clone git://git.skarnet.org/s6-networking 

• There's also a GitHub mirror of the s6-networking git repository.

Compilation

• See the enclosed INSTALL file for installation details.

Upgrade notes

• This page lists the differences to be aware of between the previous versions of s6-networking and the current one.

Reference

Commands

All these commands exit 111 if they encounter a temporary error or hardware error, and 100 if they encounter a permanent error - such as a misuse. Short-lived commands exit 0 on success. Other exit codes are documented in the relevant page.

System clock synchronization

• The s6-clockadd program
• The s6-clockview program
• The s6-sntpclock program
• The s6-taiclock program
• The s6-taiclockd program

UCSPI TCP implementation

• The s6-tcpclient program
• The s6-tcpserver program
• The s6-tcpserver4 program
• The s6-tcpserver4-socketbinder program
• The s6-tcpserver4d program
• The s6-tcpserver6 program
• The s6-tcpserver6-socketbinder program
• The s6-tcpserver6d program

UCSPI tools for SSL/TLS over TCP

• The s6-tlsclient program
• The s6-tlsserver program
• The s6-tlsc program
• The s6-tlsd program

TCP access control

• The s6-tcpserver-access program

IDENT protocol implementation

• The s6-ident-client program
• The minidentd program

Miscellaneous utilities

• The s6-getservbyname program

Libraries

• The stls library
• The sbearssl library
• The s6net library, containing:
  • The ident library interface

s6-networking discussion

• s6-networking is discussed on the skaware mailing-list.

Similar work

• ucspi-tcp is the original inspiration for s6-networking. It works, but is unfortunately unmaintained by the author. s6-networking follows the same design principles.
• ipsvd is a similar program suite.