server

A bare-bones HTTP/2 server written in C, targeting an early draft of the HTTP/2 specification (pre-RFC 7540). It handles the connection preface and sends initial SETTINGS, but does not yet process subsequent frames.

Building

Requires gcc and libpthread. No external libraries.

make

This produces a server binary.

Usage

./server <port>

The server listens on the given TCP port, accepts connections in a threaded loop (pool of 100), validates the HTTP/2 connection preface, and sends a SETTINGS frame with flow-control options enabled. The connection is then closed (the connection_established() handler is a stub).

Architecture

File	Purpose
main.c	Entry point; parses port from argv[1] and starts the server
server.c / server.h	TCP server: socket, bind, listen, accept loop with a ring-buffer thread pool
handler.c / handler.h	HTTP/2 protocol handler: frame header and settings structs, connection preface validation, initial SETTINGS exchange
callback.h	Typedef for the handler function pointer (void (*)(int sockfd))
errors.c / errors.h	die(): variadic fatal-error function with perror support
mystring.c / mystring.h	Utilities: fhexdump() for hex dumps, read_packet() for exact-length reads
Makefile	Build rules; compiles with -Wall -std=c99, links -lpthread

Notes

This implementation reflects a very early HTTP/2 draft:

• The frame header uses a 16-bit length field (the final RFC 7540 uses 24-bit).
• Frame type numbering differs from the final spec (e.g. HEADERS is 0x8, HEADERS_PRIORITY is 0x1).
• Settings IDs include SPDY-era names (UPLOAD_BANDWIDTH, DOWNLOAD_BANDWIDTH, ROUND_TRIP_TIME, CURRENT_CWND, DOWNLOAD_RETRANS_RATE).
• The connection preface can be toggled between variants via compile-time defines (PRE_AC468F3, USE_ALT_HEADER).
• The thread pool has a known race condition (marked FIXME in source).

Cleaning

make clean