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   1 #include <string.h>
   2 #include "config.h"
   3
   4 /**
   5  * net - simple IPv4/IPv6 socket library
   6  *
   7  * This code makes it simple to support IPv4 and IPv6 without speed penalty
   8  * in clients by using non-blocking simultaneous connect, and using
   9  * a convenience function to create both IPv4 and IPv6 sockets for servers.
  10  *
  11  * License: MIT
  12  *
  13  * Author: Rusty Russell <rusty@rustcorp.com.au>
  14  *
  15  * Example:
  16  *      #include <ccan/net/net.h>
  17  *      #include <sys/types.h>
  18  *      #include <sys/socket.h>
  19  *      #include <netinet/in.h>
  20  *      #include <stdio.h>
  21  *      #include <err.h>
  22  *
  23  *      int main(int argc, char *argv[])
  24  *      {
  25  *              struct addrinfo *addr;
  26  *              const char *dest, *port;
  27  *              int fd;
  28  *              union {
  29  *                      struct sockaddr s;
  30  *                      struct sockaddr_in v4;
  31  *                      struct sockaddr_in6 v6;
  32  *              } u;
  33  *              socklen_t slen = sizeof(u);
  34  *
  35  *              if (argc == 2) {
  36  *                      dest = argv[1];
  37  *                      port = "http";
  38  *              } else if (argc == 3) {
  39  *                      dest = argv[1];
  40  *                      port = argv[2];
  41  *              } else
  42  *                      errx(1, "Usage: test-net <target> [<port>]");
  43  *
  44  *              addr = net_client_lookup(dest, port, AF_UNSPEC, SOCK_STREAM);
  45  *              if (!addr)
  46  *                      err(1, "Failed to look up %s", dest);
  47  *
  48  *              fd = net_connect(addr);
  49  *              if (fd < 0)
  50  *                      err(1, "Failed to connect to %s", dest);
  51  *
  52  *              if (getsockname(fd, &u.s, &slen) == 0)
  53  *                      printf("Connected via %s\n",
  54  *                             u.s.sa_family == AF_INET6 ? "IPv6"
  55  *                             : u.s.sa_family == AF_INET ? "IPv4"
  56  *                             : "UNKNOWN??");
  57  *              else
  58  *                      err(1, "Failed to get socket type for connection");
  59  *              return 0;
  60  *      }
  61  */
  62 int main(int argc, char *argv[])
  63 {
  64         /* Expect exactly one argument */
  65         if (argc != 2)
  66                 return 1;
  67
  68         if (strcmp(argv[1], "depends") == 0) {
  69                 return 0;
  70         }
  71
  72         return 1;
  73 }