on incoming connections, compare with every possible source address.

Rational (taken from the code):

    /* This is PITA. We never know which source address an 
    * incoming/outgoing packet will have, so even with 
    * btl_tcp_if_include/exclude on the remote end, we 
    * might get a different source address. 
    * 
    * If this address isn't included in btl_proc->proc_addrs, 
    * we would erroneously drop the connection 
    */ 

merge -r18165:18167 to the trunk.

This commit was SVN r18169.

The following SVN revisions from the original message are invalid or
inconsistent and therefore were not cross-referenced:
  r18165
  r18167

ompi/mca/btl/tcp/btl_tcp_proc.c

@@ -583,30 +583,70 @@ bool mca_btl_tcp_proc_accept(mca_btl_tcp_proc_t* btl_proc, struct sockaddr* addr
     OPAL_THREAD_LOCK(&btl_proc->proc_lock);
     for( i = 0; i < btl_proc->proc_endpoint_count; i++ ) {
         mca_btl_base_endpoint_t* btl_endpoint = btl_proc->proc_endpoints[i];
+        uint16_t remote_kernel_index;
+        bool matched = false;
+        uint16_t j;
+
         /* Check all conditions before going to try to accept the connection. */
         if( btl_endpoint->endpoint_addr->addr_family != addr->sa_family ) {
             continue;
         }
 
-        switch (addr->sa_family) {
-        case AF_INET:
-            if( memcmp( &btl_endpoint->endpoint_addr->addr_inet,
-                        &(((struct sockaddr_in*)addr)->sin_addr),
-                        sizeof(struct in_addr) ) ) {
+        /* Check for alias addresses: aliases share the same remote
+         * kernel_index, so if the addresses don't match, it can still be
+         * an alias of one we want to accept.
+         */
+        remote_kernel_index = btl_endpoint->endpoint_addr->addr_ifkindex;
+
+        for (j=0; j < btl_proc->proc_addr_count; j++) {
+            mca_btl_tcp_addr_t* exported_address = btl_proc->proc_addrs + j;
+
+#if 0
+            /* This is PITA. We never know which source address an
+             * incoming/outgoing packet will have, so even with
+             * btl_tcp_if_include/exclude on the remote end, we
+             * might get a different source address.
+             *
+             * If this address isn't included in btl_proc->proc_addrs,
+             * we would erroneously drop the connection
+             */
+            if (remote_kernel_index != exported_address->addr_ifkindex) {
+                /* kernel_index doesn't match, so that's not a possible
+                 * alias
+                 */
                 continue;
             }
-            break;
-#if OPAL_WANT_IPV6
-        case AF_INET6:
-            if( memcmp( &btl_endpoint->endpoint_addr->addr_inet,
-                        &(((struct sockaddr_in6*)addr)->sin6_addr),
-                        sizeof(struct in6_addr) ) ) {
-                continue;
-            }
-            break;
 #endif
-        default:
-            ;
+
+            switch (addr->sa_family) {
+                case AF_INET:
+                    /* if (aliases) addresses match, accept it */
+                    if(!memcmp( &exported_address->addr_inet,
+                                &(((struct sockaddr_in*)addr)->sin_addr),
+                                sizeof(struct in_addr) ) ) {
+                        matched = true;
+                    }
+                    break;
+#if OPAL_WANT_IPV6
+                case AF_INET6:
+                    if(IN6_ARE_ADDR_EQUAL(
+                                &exported_address->addr_inet,
+                                &(((struct sockaddr_in6*)addr)->sin6_addr))) {
+                        matched = true;
+                    }
+                    break;
+#endif
+                default:
+                    ;
+            }
+        }
+
+        /* do we have a match for the incoming address? Read: is there a
+         * btl_endpoint with an address configured for the same remote
+         * NIC? If not, check the next btl_endpoint
+         */
+        if (false == matched) {
+            continue;
         }
 
         if(mca_btl_tcp_endpoint_accept(btl_endpoint, addr, sd)) {