7 #include <sys/socket.h>
10 #include <arpa/inet.h>
14 static char *get_sockname(struct addrinfo *addr) {
15 static char buf[INET6_ADDRSTRLEN+1];
16 struct sockaddr_storage local;
20 if ((fd = socket(addr->ai_family, SOCK_DGRAM, 0)) == -1) {
25 /* Since the socket was created with SOCK_DGRAM, this is
26 * actually not establishing a connection or generating
27 * any other network traffic. Instead, as a side-effect,
28 * it saves the local address with which packets would
29 * be sent to the destination. */
30 if (connect(fd, addr->ai_addr, addr->ai_addrlen) == -1) {
31 /* We don’t display the error here because most
32 * likely, there just is no IPv6 connectivity.
33 * Thus, don’t spam the user’s console but just
34 * try the next address. */
39 socklen_t local_len = sizeof(struct sockaddr_storage);
40 if (getsockname(fd, (struct sockaddr*)&local, &local_len) == -1) {
41 perror("getsockname()");
46 memset(buf, 0, INET6_ADDRSTRLEN + 1);
47 if ((ret = getnameinfo((struct sockaddr*)&local, local_len,
48 buf, sizeof(buf), NULL, 0,
49 NI_NUMERICHOST)) != 0) {
50 fprintf(stderr, "getnameinfo(): %s\n", gai_strerror(ret));
60 * Returns the IPv6 address with which you have connectivity at the moment.
61 * The char * is statically allocated and mustn't be freed
63 static char *get_ipv6_addr() {
64 struct addrinfo hints;
65 struct addrinfo *result, *resp;
66 static struct addrinfo *cached = NULL;
68 /* To save dns lookups (if they are not cached locally) and creating
69 * sockets, we save the fd and keep it open. */
71 return get_sockname(cached);
73 memset(&hints, 0, sizeof(struct addrinfo));
74 hints.ai_family = AF_INET6;
75 hints.ai_socktype = SOCK_DGRAM;
77 /* We resolve the K root server to get a public IPv6 address. You can
78 * replace this with any other host which has an AAAA record, but the
79 * K root server is a pretty safe bet. */
80 if (getaddrinfo("k.root-servers.net", "domain", &hints, &result) != 0) {
81 /* We don’t display the error here because most
82 * likely, there just is no connectivity.
83 * Thus, don’t spam the user’s console. */
87 for (resp = result; resp != NULL; resp = resp->ai_next) {
88 char *addr_string = get_sockname(resp);
89 /* If we could not get our own address and there is more than
90 * one result for resolving k.root-servers.net, we cannot
91 * cache. Otherwise, no matter if we got IPv6 connectivity or
92 * not, we will cache the (single) result and are done. */
93 if (!addr_string && result->ai_next != NULL)
96 if ((cached = malloc(sizeof(struct addrinfo))) == NULL)
98 memcpy(cached, resp, sizeof(struct addrinfo));
99 if ((cached->ai_addr = malloc(resp->ai_addrlen)) == NULL) {
103 memcpy(cached->ai_addr, resp->ai_addr, resp->ai_addrlen);
104 freeaddrinfo(result);
108 freeaddrinfo(result);
112 void print_ipv6_info(const char *format_up, const char *format_down) {
114 char *addr_string = get_ipv6_addr();
116 if (output_format == O_I3BAR)
117 printf("{\"name\":\"ipv6\", \"full_text\":\"");
119 if (addr_string == NULL) {
120 printf("%s", format_down);
124 for (walk = format_up; *walk != '\0'; walk++) {
130 if (strncmp(walk+1, "ip", strlen("ip")) == 0) {
131 printf("%s", addr_string);
132 walk += strlen("ip");
136 if (output_format == O_I3BAR)