Try to be better about handling the results of getaddrinfo(): when

[rsync/rsync.git] / socket.c

diff --git a/socket.c b/socket.c
index 993431d..e642082 100644 (file)
--- a/socket.c
+++ b/socket.c
@@ -245,6 +245,18 @@ int open_socket_out_wrapped (char *host,
 /**
  * Open a socket of the specified type, port and address for incoming data
  *
+ * Try to be better about handling the results of getaddrinfo(): when
+ * opening an inbound socket, we might get several address results,
+ * e.g. for the machine's ipv4 and ipv6 name.  
+ * 
+ * If binding a wildcard, then any one of them should do.  If an address
+ * was specified but it's insufficiently specific then that's not our
+ * fault.  
+ * 
+ * However, some of the advertized addresses may not work because e.g. we
+ * don't have IPv6 support in the kernel.  In that case go on and try all
+ * addresses until one succeeds.
+ * 
  * @param bind_address Local address to bind, or NULL to allow it to
  * default.
  **/
@@ -253,7 +265,7 @@ static int open_socket_in(int type, int port, const char *bind_address,
 {
        int one=1;
        int s;
-       struct addrinfo hints, *res;
+       struct addrinfo hints, *res, *resp;
        char portbuf[10];
        int error;
 
@@ -268,20 +280,32 @@ static int open_socket_in(int type, int port, const char *bind_address,
                        bind_address, gai_strerror(error));
                return -1;
        }
-       if (res->ai_next) {
-               rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: "
-                       "resolved to multiple hosts\n",
-                       bind_address);
-               freeaddrinfo(res);
-               return -1;
-       }
+       /* XXX: Do we need to care about getting multiple results
+        * back?  I think probably not; if the user passed
+        * bind_address == NULL and we set AI_PASSIVE then we ought to
+        * get a wildcard result. */
 
-       s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
-       if (s < 0) {
-               rprintf(FERROR, RSYNC_NAME ": open socket in failed: %s\n",
-                       strerror(errno)); 
-               freeaddrinfo(res);
-               return -1; 
+       resp = res;
+       while (1) {
+               s = socket(resp->ai_family, resp->ai_socktype, resp->ai_protocol);
+
+               if (s >= 0) {
+                       break;  /* got a socket */
+               } else if ((resp = resp->ai_next)) {
+                       switch (errno) {
+                       case EPROTONOSUPPORT:
+                       case EAFNOSUPPORT:
+                       case EPFNOSUPPORT:
+                               /* See if there's another address that will work... */
+                               continue;
+                       }
+               }
+               
+               rprintf(FERROR, RSYNC_NAME ": open inbound socket"
+                       "(dom=%d, type=%d, proto=%d) failed: %s\n",
+                       resp->ai_family, resp->ai_socktype, resp->ai_protocol,
+                       strerror(errno));
+                       goto fail;
        }
 
        setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one));
@@ -289,12 +313,15 @@ static int open_socket_in(int type, int port, const char *bind_address,
        /* now we've got a socket - we need to bind it */
        if (bind(s, res->ai_addr, res->ai_addrlen) < 0) { 
                rprintf(FERROR, RSYNC_NAME ": bind failed on port %d\n", port);
-               freeaddrinfo(res);
-               close(s); 
-               return -1;
+               close(s);
+               goto fail;
        }
 
        return s;
+
+fail:
+       freeaddrinfo(res);
+       return -1; 
 }