loader.c

#include <stdio.h>
#include <unistd.h>
#include <bpf/libbpf.h>
#include <fcntl.h>
#include <signal.h>

// Auto-generated by bpftool
#include "sockmap_accel.bpf.skel.h"

#define CGROUP_PATH "/sys/fs/cgroup"

static volatile int stop = 0;

void sig_handler(int signo) {
	stop = 1;
}

static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args) {
	return vfprintf(stderr, format, args);
}

int main(int argc, char **argv) {
	if (argc < 2) {
		fprintf(stderr, "Usage: %s <sockperf server port>\n", argv[0]);
		return 1;
	}
	int server_port = atoi(argv[1]);

	// Setup signal handlers to ensure cleanup before termination
	signal(SIGINT, sig_handler);
	signal(SIGTERM, sig_handler);

	// Setup logger
	libbpf_set_print(libbpf_print_fn);

	// (1) Open and load BPF skeleton
	struct sockmap_accel_bpf *skel = sockmap_accel_bpf__open();
	if (!skel) {
		fprintf(stderr, "Failed to open BPF skeleton\n");
		return 1;
	}

	int err = sockmap_accel_bpf__load(skel);
	if (err) {
		fprintf(stderr, "Failed to load BPF skeleton: %d\n", err);
		goto out_bpf_destroy;
	}

	// Set server port in the BPF program
	skel->bss->server_port = server_port;

	// (2) Attach SOCK_OPS to Cgroup
	int cgroup_fd = open(CGROUP_PATH, O_RDONLY);
	if (cgroup_fd < 0) {
		fprintf(stderr, "Failed to open cgroup: %s\n", CGROUP_PATH);
		goto out_bpf_destroy;
	}

	skel->links.bpf_sockmap_handler = bpf_program__attach_cgroup(
		skel->progs.bpf_sockmap_handler, cgroup_fd);
	if (!skel->links.bpf_sockmap_handler) {
		fprintf(stderr, "Failed to attach SOCK_OPS to cgroup\n");
		goto out_cgroup_close;
	}
	printf("SOCK_OPS attached.\n");

	// (3) Attach SK_MSG to SOCKMAP
	skel->links.bpf_redir_handler = bpf_program__attach_sockmap(
		skel->progs.bpf_redir_handler,
		bpf_map__fd(skel->maps.sock_map)
	);
	if (!skel->links.bpf_redir_handler) {
		fprintf(stderr, "Failed to attach SK_MSG to map\n");
		goto out_cgroup_close;
	}
	printf("SK_MSG attached.\n");

	printf("=== SOCKMAP Acceleration Running ===\n");
	printf("Press Ctrl+c to stop.\n");

	while (!stop) {
		sleep(1);
	}

out_cgroup_close:
	close(cgroup_fd);
out_bpf_destroy:
	sockmap_accel_bpf__destroy(skel);
	return 0;
}