ComputerNetworking_TAMU

Files for ECEN 602

Most of the programs have simple makefiles to build, and are wrapped in nix derivations for convenience. If you don't have nix installed, you can cd to a Machine Problem directory, run make and then run the applications.

Machine Problems

MP1: Echo Server/Client

Simple TCP echo server according to RFC 862 and a basic client
Server command: nix run .#echos <port>
Client command: nix run .#echo <server> <port>

MP2: Simple Broadcast Chat Server

Simple Broadcast Chat Server accoring to the Design doc with all extra features implemented
Server command: nix run .#sbcp_server <ip> <port> <max_clients>
Client command: nix run .#sbcp_client <username> <server> <port>

MP3: Trivial File Transfer Protocol

TFTP server per RFC 1350 with netascii support
Server command: nix run .#tftp_server (serves on port 8080)

MP4: Simple HTTP Proxy

HTTP client, proxy, and server built on libhttp
Client command: nix run .#http_client <proxy> <port> <url>
Proxy command: nix run .#http_proxy <ip> <port>
Server command: nix run .#http_server <port>

NixOS Modules

Each server is packaged as a NixOS module under services.ecen602.*, available via the flake's nixosModules output:

{
  imports = [ inputs.ecen602.nixosModules.default ];

  services.ecen602 = {
    echos.enable = true;
    sbcp.enable = true;
    tftp.enable = true;
    http-server.enable = true;
    http-proxy.enable = true;
  };
}

Every module supports package, port/listen-address options, and openFirewall. The SBCP server and HTTP proxy accept IPv4 or IPv6 listenAddress literals (IPv4 is mapped automatically).

Integration Tests

The MPs are exercised end-to-end by NixOS integration tests running in systemd-nspawn containers (tests/):

nix flake check          # lint + all tests
nix build -L .#checks.x86_64-linux.mp2-sbcp-chat   # single test

Container tests boot in ~2-3s each and need no KVM. The Nix daemon on the machine running them requires:

nix.settings = {
  experimental-features = [ "auto-allocate-uids" "cgroups" ];
  auto-allocate-uids = true;
  extra-system-features = [ "uid-range" ];
};