6 #include <sys/socket.h>
12 * Returns the IPv6 address with which you have connectivity at the moment.
15 const char *get_ipv6_addr() {
16 static char buf[INET6_ADDRSTRLEN+1];
17 struct addrinfo hints;
18 struct addrinfo *result, *resp;
21 memset(&hints, 0, sizeof(struct addrinfo));
22 hints.ai_family = AF_INET6;
24 /* We resolve the K root server to get a public IPv6 address. You can
25 * replace this with any other host which has an AAAA record, but the
26 * K root server is a pretty safe bet. */
27 if (getaddrinfo("k.root-servers.net", "domain", &hints, &result) != 0) {
28 perror("getaddrinfo()");
32 for (resp = result; resp != NULL; resp = resp->ai_next) {
33 if ((fd = socket(resp->ai_family, SOCK_DGRAM, 0)) == -1) {
38 /* Since the socket was created with SOCK_DGRAM, this is
39 * actually not establishing a connection or generating
40 * any other network traffic. Instead, as a side-effect,
41 * it saves the local address with which packets would
42 * be sent to the destination. */
43 if (connect(fd, resp->ai_addr, resp->ai_addrlen) == -1) {
49 struct sockaddr_storage local;
50 socklen_t local_len = sizeof(struct sockaddr_storage);
51 if (getsockname(fd, (struct sockaddr*)&local, &local_len) == -1) {
52 perror("getsockname()");
59 memset(buf, 0, INET6_ADDRSTRLEN + 1);
61 if ((ret = getnameinfo((struct sockaddr*)&local, local_len,
62 buf, sizeof(buf), NULL, 0,
63 NI_NUMERICHOST)) != 0) {
64 fprintf(stderr, "getnameinfo(): %s\n", gai_strerror(ret));