[lib] getaddrinfo() in create_udp_listening_socket()

libowlps/libowlps.c

@@ -481,32 +481,48 @@ int owl_create_udp_trx_socket(const char *const server_address,
  */
 int owl_create_udp_listening_socket(const uint_fast16_t port)
 {
+  char port_str[6] ;
+  struct addrinfo
+    gai_hints,
+    *gai_results = NULL,
+    *gai_res = NULL ;
+  int gai_ret ; // Return value of getaddrinfo()
   int sockfd ; // Socket descriptor
-  struct sockaddr_in server_description ; // Server structure
-  int ret = 0 ; // Return value
 
-  /* Create the UDP socket */
-  sockfd = socket(AF_INET, SOCK_DGRAM, 0) ;
-  if (sockfd < 0)
+  /* Get the server information */
+  sprintf(port_str, "%"PRIuFAST16, port) ;
+  memset(&gai_hints, 0, sizeof(struct addrinfo)) ;
+  gai_hints.ai_family = AF_INET ; // IPv4 only
+  gai_hints.ai_socktype = SOCK_DGRAM ;
+  gai_hints.ai_flags = AI_PASSIVE ;
+  gai_ret = getaddrinfo(NULL, port_str, &gai_hints, &gai_results) ;
+  if (gai_ret)
     {
-      perror("UDP socket creation failed") ;
+      fprintf(stderr, "UDP socket creation failed: getaddrinfo(): %s\n",
+              gai_strerror(gai_ret)) ;
       return -OWL_ERR_SOCKET_CREATE ;
     }
 
-  /* Initialise the server structure */
-  memset(&server_description, 0, sizeof(server_description)) ;
-  server_description.sin_family = AF_INET ; // INET socket
-  // All the connections are accepted:
-  server_description.sin_addr.s_addr = htonl(INADDR_ANY) ;
-  server_description.sin_port = htons(port) ; // Listening port
-
-  /* Port reservation */
-  ret = bind(sockfd, (struct sockaddr*) &server_description,
-             sizeof(server_description)) ;
-  if (ret < 0)
+  /* Create the UDP socket:
+   * loop until both socket() and bind() succeed */
+  for (gai_res = gai_results ; gai_res != NULL ;
+       gai_res = gai_res->ai_next)
     {
-      perror("Cannot bind the UDP socket") ;
+      sockfd = socket(gai_res->ai_family, gai_res->ai_socktype,
+                      gai_res->ai_protocol) ;
+      if (sockfd == -1)
+        continue ;
+
+      if (! bind(sockfd, gai_res->ai_addr, gai_res->ai_addrlen))
+        break ; // Success!
+
       close(sockfd) ;
+    }
+
+  if (gai_res == NULL)
+    {
+      fprintf(stderr,
+              "UDP socket creation failed: socket() or bind().\n") ;
       return -OWL_ERR_SOCKET_CREATE ;
     }