int main()

in bpf/xdpsock_user.c [1885:2024]
112 lines of code
30 McCabe index (conditional complexity)

int main(int argc, char **argv)
{
	struct __user_cap_header_struct hdr = { _LINUX_CAPABILITY_VERSION_3, 0 };
	struct __user_cap_data_struct data[2] = { { 0 } };
	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
	bool rx = false, tx = false;
	struct sched_param schparam;
	struct xsk_umem_info *umem;
	struct bpf_object *obj;
	int xsks_map_fd = 0;
	pthread_t pt;
	int i, ret;
	void *bufs;

	parse_command_line(argc, argv);

	if (opt_reduced_cap) {
		if (capget(&hdr, data)  < 0)
			fprintf(stderr, "Error getting capabilities\n");

		data->effective &= CAP_TO_MASK(CAP_NET_RAW);
		data->permitted &= CAP_TO_MASK(CAP_NET_RAW);

		if (capset(&hdr, data) < 0)
			fprintf(stderr, "Setting capabilities failed\n");

		if (capget(&hdr, data)  < 0) {
			fprintf(stderr, "Error getting capabilities\n");
		} else {
			fprintf(stderr, "Capabilities EFF %x Caps INH %x Caps Per %x\n",
				data[0].effective, data[0].inheritable, data[0].permitted);
			fprintf(stderr, "Capabilities EFF %x Caps INH %x Caps Per %x\n",
				data[1].effective, data[1].inheritable, data[1].permitted);
		}
	} else {
		if (setrlimit(RLIMIT_MEMLOCK, &r)) {
			fprintf(stderr, "ERROR: setrlimit(RLIMIT_MEMLOCK) \"%s\"\n",
				strerror(errno));
			exit(EXIT_FAILURE);
		}

		if (opt_num_xsks > 1)
			load_xdp_program(argv, &obj);
	}

	/* Reserve memory for the umem. Use hugepages if unaligned chunk mode */
	bufs = mmap(NULL, NUM_FRAMES * opt_xsk_frame_size,
		    PROT_READ | PROT_WRITE,
		    MAP_PRIVATE | MAP_ANONYMOUS | opt_mmap_flags, -1, 0);
	if (bufs == MAP_FAILED) {
		printf("ERROR: mmap failed\n");
		exit(EXIT_FAILURE);
	}

	/* Create sockets... */
	umem = xsk_configure_umem(bufs, NUM_FRAMES * opt_xsk_frame_size);
	if (opt_bench == BENCH_RXDROP || opt_bench == BENCH_L2FWD) {
		rx = true;
		xsk_populate_fill_ring(umem);
	}
	if (opt_bench == BENCH_L2FWD || opt_bench == BENCH_TXONLY)
		tx = true;
	for (i = 0; i < opt_num_xsks; i++)
		xsks[num_socks++] = xsk_configure_socket(umem, rx, tx);

	for (i = 0; i < opt_num_xsks; i++)
		apply_setsockopt(xsks[i]);

	if (opt_bench == BENCH_TXONLY) {
		if (opt_tstamp && opt_pkt_size < PKTGEN_SIZE_MIN)
			opt_pkt_size = PKTGEN_SIZE_MIN;

		gen_eth_hdr_data();

		for (i = 0; i < NUM_FRAMES; i++)
			gen_eth_frame(umem, i * opt_xsk_frame_size);
	}

	if (opt_num_xsks > 1 && opt_bench != BENCH_TXONLY)
		enter_xsks_into_map(obj);

	if (opt_reduced_cap) {
		ret = recv_xsks_map_fd(&xsks_map_fd);
		if (ret) {
			fprintf(stderr, "Error %d receiving xsks_map_fd\n", ret);
			exit_with_error(ret);
		}
		if (xsks[0]->xsk) {
			ret = xsk_socket__update_xskmap(xsks[0]->xsk, xsks_map_fd);
			if (ret) {
				fprintf(stderr, "Update of BPF map failed(%d)\n", ret);
				exit_with_error(ret);
			}
		}
	}

	signal(SIGINT, int_exit);
	signal(SIGTERM, int_exit);
	signal(SIGABRT, int_exit);

	setlocale(LC_ALL, "");

	if (!opt_quiet) {
		ret = pthread_create(&pt, NULL, poller, NULL);
		if (ret)
			exit_with_error(ret);
	}

	prev_time = get_nsecs();
	start_time = prev_time;

	/* Configure sched priority for better wake-up accuracy */
	memset(&schparam, 0, sizeof(schparam));
	schparam.sched_priority = opt_schprio;
	ret = sched_setscheduler(0, opt_schpolicy, &schparam);
	if (ret) {
		fprintf(stderr, "Error(%d) in setting priority(%d): %s\n",
			errno, opt_schprio, strerror(errno));
		goto out;
	}

	if (opt_bench == BENCH_RXDROP)
		rx_drop_all();
	else if (opt_bench == BENCH_TXONLY)
		tx_only_all();
	else
		l2fwd_all();

out:
	benchmark_done = true;

	if (!opt_quiet)
		pthread_join(pt, NULL);

	xdpsock_cleanup();

	munmap(bufs, NUM_FRAMES * opt_xsk_frame_size);

	return 0;
}