tests/test_getaddrinfo.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <netdb.h>
   4 #include <netinet/in.h>
   5 #include <sys/socket.h>
   6 #include <assert.h>
   7 #include <string.h>
   8
   9 #ifndef   NI_MAXHOST
  10 #define   NI_MAXHOST 1025
  11 #endif
  12
  13 static int doit(const char* host, const char* service) {
  14         struct addrinfo *result;
  15         struct addrinfo *res;
  16         int error;
  17
  18         /* resolve the domain name into a list of addresses */
  19         error = getaddrinfo(host, service, NULL, &result);
  20         if (error != 0)
  21         {
  22                 fprintf(stderr, "error in getaddrinfo: %s\n", gai_strerror(error));
  23                 return EXIT_FAILURE;
  24         }
  25
  26         /* loop over all returned results and do inverse lookup */
  27         for (res = result; res != NULL; res = res->ai_next)
  28         {
  29                 char hostname[NI_MAXHOST] = "";
  30
  31                 error = getnameinfo(res->ai_addr, res->ai_addrlen, hostname, NI_MAXHOST, NULL, 0, 0);
  32                 if (error != 0)
  33                 {
  34                 fprintf(stderr, "error in getnameinfo: %s\n", gai_strerror(error));
  35                 continue;
  36                 }
  37                 int port = 0;
  38                 if(res->ai_family == AF_INET) port = ((struct sockaddr_in*)res->ai_addr)->sin_port;
  39                 else if(res->ai_family == AF_INET6) port = ((struct sockaddr_in6*)res->ai_addr)->sin6_port;
  40                 port = ntohs(port);
  41                 printf("hostname: %s, port: %d\n", hostname, port);
  42         }
  43
  44         freeaddrinfo(result);
  45         return EXIT_SUCCESS;
  46 }
  47
  48 /* reproduce use of getaddrinfo as used by nmap 7.91's canonicalize_address */
  49 int canonicalize_address(struct sockaddr_storage *ss, struct sockaddr_storage *output) {
  50         char canonical_ip_string[NI_MAXHOST];
  51         struct addrinfo *ai;
  52         int rc;
  53         /* Convert address to string. */
  54         rc = getnameinfo((struct sockaddr *) ss, sizeof(*ss),
  55                 canonical_ip_string, sizeof(canonical_ip_string), NULL, 0, NI_NUMERICHOST);
  56         assert(rc == 0);
  57         struct addrinfo hints = {
  58                 .ai_family = ss->ss_family,
  59                 .ai_socktype = SOCK_DGRAM,
  60                 .ai_flags = AI_NUMERICHOST,
  61         };
  62         rc = getaddrinfo(canonical_ip_string, NULL, &hints, &ai);
  63         if (rc != 0 || ai == NULL)
  64                 return -1;
  65         assert(ai->ai_addrlen > 0 && ai->ai_addrlen <= (int) sizeof(*output));
  66         memcpy(output, ai->ai_addr, ai->ai_addrlen);
  67         freeaddrinfo(ai);
  68         return 0;
  69 }
  70
  71 int main(void) {
  72         int ret;
  73         ret = doit("www.example.com", NULL);
  74         ret = doit("www.example.com", "80");
  75         struct sockaddr_storage o, ss = {.ss_family = PF_INET};
  76         struct sockaddr_in *v4 = &ss;
  77         struct sockaddr_in6 *v6 = &ss;
  78         memcpy(&v4->sin_addr, "\x7f\0\0\1", 4);
  79         ret = canonicalize_address(&ss, &o);
  80         assert (ret == 0);
  81         ss.ss_family = PF_INET6;
  82         memcpy(&v6->sin6_addr, "\0\0\0\0" "\0\0\0\0" "\0\0\0\0""\0\0\0\1", 16);
  83         ret = canonicalize_address(&ss, &o);
  84         assert (ret == 0);
  85         return ret;
  86 }