#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int
main(void)
{
	int sock;
	struct sockaddr_in6 server_addr, source_addr;
	struct in6_pktinfo pktinfo;
	char buf[256];

	/* Create IPv6 TCP socket */
	sock = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
	if (sock < 0) {
		perror("socket");
		return (1);
	}

	/* Set outgoing interface via IPV6_PKTINFO socket option */
	memset(&pktinfo, 0, sizeof(pktinfo));
	/* HERE IS THE ifindex */
	pktinfo.ipi6_ifindex = 3;

	if (setsockopt(sock, IPPROTO_IPV6, IPV6_PKTINFO, &pktinfo,
	    sizeof(pktinfo)) < 0) {
		perror("setsockopt IPV6_PKTINFO");
		close(sock);
		return (1);
	}

	/* Set up destination address */
	memset(&server_addr, 0, sizeof(server_addr));
	server_addr.sin6_family = AF_INET6;
	server_addr.sin6_port = htons(80);
	inet_pton(AF_INET6, "2606:4700::6810:b8f1", &server_addr.sin6_addr);

	/* Connect to server */
	if (connect(sock, (struct sockaddr *)&server_addr,
	    sizeof(server_addr)) < 0) {
		perror("connect");
		close(sock);
		return (1);
	}

	printf("Connected successfully!\n");

	/* Send GET request before */
	const char *get_request = "GET / HTTP/1.1\r\nHost: icanhazip.com\r\n"
	    "Connection: close\r\n\r\n";
	if (send(sock, get_request, strlen(get_request), 0) < 0) {
		perror("send");
		close(sock);
		return (1);
	}

	printf("Sent GET request\n");

	/* Send GET request after */
	if (send(sock, get_request, strlen(get_request), 0) < 0) {
		perror("send");
		close(sock);
		return (1);
	}

	printf("Recv GET response\n");

	/* Receive response */
	ssize_t n;
	while ((n = recv(sock, buf, sizeof(buf) - 1, 0)) > 0) {
		buf[n] = '\0';
		printf("%s", buf);
	}

	close(sock);
	return (0);
}