#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>

#define DEAD_IP "127.16.0.1"
#define fail_if(arg) if (0 != (arg)) { \
	fprintf(stderr, "Failed at %d: %s\n", __LINE__, #arg);\
	return 1; };

void handler(int sig)
{
	// printf("Got signal %d\n", sig);
}

int _test(int proto, int timeo, int blocking)
{
	struct sockaddr_in addr4 = { .sin_family = AF_INET, .sin_port = htons(5555) };
	struct sockaddr *deadaddr = (struct sockaddr *)&addr4;
	struct sigaction sa = { .sa_handler = handler, .sa_flags = SA_RESTART }; 
	struct timeval tv = { .tv_sec = 300 };
	int sk, rtn;

	fail_if(1 != inet_pton(AF_INET, DEAD_IP, &addr4.sin_addr));
	fail_if(0 > (sk = socket(PF_INET,
			SOCK_STREAM | (blocking ? 0 : SOCK_NONBLOCK), proto)));
	if (timeo) {
		fail_if(setsockopt(sk, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof tv));
	}
	fail_if(sigaction(SIGALRM, &sa, NULL));
	fail_if(alarm(3) < 0);

	rtn = connect(sk, deadaddr, sizeof *deadaddr);

	printf("  1st connect - rtn: %d errno: %d (%s)\n", rtn, errno, strerror(errno));
	rtn = connect(sk, deadaddr, sizeof *deadaddr);
	printf("  2nd connect - rtn: %d errno: %d (%s)\n", rtn, errno, strerror(errno));

	close(sk);
	return 0;
}

#define test(proto, timeo, blocking) \
	(printf("Testing " #proto " on a %s%sblocking socket\n", \
		timeo ? "timeo " : "", blocking ? "" : "non-"), \
		_test(proto, timeo, blocking))

int main(int argc, char *argv[])
{
	setlinebuf(stdout);
	fail_if(system("iptables -I OUTPUT -d " DEAD_IP "/32 -j DROP"));
	test(IPPROTO_SCTP, 0, 1);
	test(IPPROTO_TCP, 0, 1);
	test(IPPROTO_SCTP, 1, 1);
	test(IPPROTO_TCP, 1, 1);
	test(IPPROTO_SCTP, 0, 0);
	test(IPPROTO_TCP, 0, 0);
	test(IPPROTO_SCTP, 1, 1);
	test(IPPROTO_TCP, 1, 1);
	fail_if(system("iptables -D OUTPUT -d " DEAD_IP "/32 -j DROP"));
}