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.

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; 
 }