libhive

libhive is a standalone HTTP/2 protocol engine in C11 for Linux and OpenBSD. It implements framing, stream state management, HPACK, flow control, push, GOAWAY, and h2c, while doing zero I/O: you feed received bytes into hive_session_recv(), submit work with hive_submit_*(), and flush queued frames with hive_session_send() through your own transport layer.

Requirements

• C11 compiler (project uses clang in the default Makefile)
• libc only for the core library

Build and Install

make
make install

Optional install prefix:

make install PREFIX=/opt/libhive

Minimal Integration Example (Server Role)

The snippet below shows the event-loop pattern from ARCHITECTURE.md §10 in minimal form: read -> recv -> submit (inside callbacks) -> send.

#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include "hive.h"

static ssize_t
transport_send(hive_session_t *s, const struct iovec *iov, int iovcnt, void *ud)
{
	size_t i;
	ssize_t total;

	(void)s;
	(void)ud;
	total = 0;
	for (i = 0; i < (size_t)iovcnt; i++)
		total += (ssize_t)iov[i].iov_len;
	return total; /* full write */
}

static ssize_t
transport_read(uint8_t *buf, size_t cap)
{
	(void)buf;
	(void)cap;
	return 0; /* no inbound bytes in this tiny runnable example */
}

int
main(void)
{
	hive_session_t *session;
	hive_callbacks_t cb;
	uint8_t inbuf[4096];
	ssize_t nread;

	memset(&cb, 0, sizeof(cb));
	cb.send = transport_send;

	session = hive_session_server_new(NULL, NULL, &cb, NULL);
	if (session == NULL)
		return 1;

	nread = transport_read(inbuf, sizeof(inbuf));
	if (nread > 0)
		(void)hive_session_recv(session, inbuf, (size_t)nread);

	if (hive_session_want_write(session))
		(void)hive_session_send(session);

	hive_session_free(session);
	return 0;
}

Build and run this example locally against the built static library:

make release
clang -std=c11 -Wall -Wextra -Wpedantic -Iinclude \
  /tmp/libhive_example.c build/rel/libhive.a -o /tmp/libhive_example
/tmp/libhive_example

Known Limitations

• Zero I/O by design: sockets/TLS/event-loop ownership is entirely caller-side
• Not thread-safe per session (hive_session_recv/send/submit/free must not race)
• Single-session configuration is fixed at creation (no live option mutation)
• Out of scope in v1: HTTP/3, RFC 8441 extended CONNECT/WebSocket, RFC 9218

More Documentation

• Full design and state machines: ARCHITECTURE.md
• Build and toolchain details: TECH_STACK.md
• Coding rules and lifetime contracts: CODING_STANDARDS.md
• Test strategy and gates: TESTING.md

License

ISC