#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <err.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <sysexits.h>

static bool closehalf = false;

static void *
worker(void *arg)
{
	u_int nsockets = *(u_int *)arg, half = nsockets / 2;
	int *sockets;
	u_short seed[3];

	sockets = malloc(nsockets * sizeof(int));
	arc4random_buf(seed, sizeof(seed));

	for (u_int i = 0; i < nsockets; i++) {
		char s[INET_ADDRSTRLEN];
		struct sockaddr_in sin = { .sin_family = AF_INET };
		long r;
		int rv;

		sockets[i] = socket(AF_INET, SOCK_DGRAM, 0);
		if(__predict_false(sockets[i] == -1)) {
			warn("Socket");
			continue;
		}
		do {
			r = nrand48(seed);
			sin.sin_port = (u_short)(r >> 24);
		} while (__predict_false(sin.sin_port == 0));
		sin.sin_addr.s_addr = htonl((10 << 24) | ((u_int)r & 0xffffff));
		rv = connect(sockets[i], (struct sockaddr *)&sin, sizeof(sin));
		if (__predict_false(rv != 0))
			warn("Connect to %s:%u",
			    inet_ntop(AF_INET, &sin.sin_addr, s, sizeof(s)),
			    ntohs(sin.sin_port));
		if (closehalf && i >= half)
			close(sockets[i -  half]);
	}

	return (NULL);
}

int
main(int argc, char *argv[])
{
	u_int nthreads = (u_int)sysconf(_SC_NPROCESSORS_ONLN);
	u_int nsockets = 1000;
	pthread_t *threads;
	int c;

	while ((c = getopt(argc, argv, "cn:t:")) != -1)
		switch (c) {
		case 'c':
			closehalf = true;
			break;
		case 'n':
			nsockets = (u_int)strtol(optarg, NULL, 10);
			break;
		case 't':
			nthreads = (u_int)strtol(optarg, NULL, 10);
			break;
		default:
			errx(EX_USAGE,
			    "Usage: %s [-c] [-n sockets] [-t threads]",
			    argv[0]);
		}

	printf("%u threads, %u sockets\n", nthreads, nsockets);

	threads = malloc(nthreads * sizeof(pthread_t));

	for (u_int i = 0; i < nthreads; i++)
		pthread_create(&threads[i], NULL, worker, &nsockets);

	for (u_int i = 0; i < nthreads; i++)
		pthread_join(threads[i], NULL);
}