TCP/IP Stack

Overview

This project is an implementation of TCP/IPv6 stack. It is intended to be portable between different hardware and operating systems. The hw.h specifies functions that have to be provided by a target platform. An implementation for x86 Linux-based platform is provided in hw.c file.

The stack was created as an academic research project. It doesn't implement the whole TCP/IPv6 specification. Particularly no optional IPv6 headers are supported, and the TCPv6 implementation is incomplete (although functional). The code is not intended for production use.

Compilation

The code relies on some GCC features like attribute(packed) and support of -std=gnu11 flag. Therefore it can only be compiled with a modern GCC-compatible compiler. CMake is also a dependency.

To compile the project issue following commands in the terminal:

$ mkdir build/
$ cd build
$ cmake ..
$ make

The compilation will output build/src/libtcpip.a library and build/src/test executable.

Usage

The project includes a basic main.c which contains a main function to demonstrate some of the functionality.

The net.h header contain main function declarations of the library's interface. The TCP listen function has no net.h wrapper and has to be accessed directly from the tcp.h. While both tcp.h and `udp.h functions can be accessed directly, we recommend not using functions of IP layer and lower.

The following example code sends a TCP message. The first argument of net_init contains a string by which the platform-specific implementation selects a network interface. The Linux implementation connects directly to a raw packet socket, so the executable needs appropriate system privileges (see man 7 packet for more details).

#include "net.h"

extern uint8_t *src_ip;   // must contain an src IPv6 IP. This doesn't have to
                          // be an address given to the network interface by the
                          // kernel
extern uint16_t src_port; // must contain an src port.

extern uint8_t *dst_ip;   // must contain a destination IPv6 IP.
extern uint16_t dst_port; // must contain an dst port.

const char *buffer = "Hello World!";
session_t *session = net_init("eth0", src_ip, src_port, dst_ip, dst_port, TCP, -1);
net_send(session, 0, 0, (uint8_t*) buffer, strlen(buffer));
net_free(session);

Documentation

The headers are fully documented in-code using Doxygen. The documentation can be generated using the make doc command. build/doc/Doxyfile.in will contain default Doxygen settings for the project. By default HTML and LaTeX documentation are generated.