1 files changed, 24 insertions, 6 deletions

diff --git a/common/socket.c b/common/socket.c
index 26cf496..749e0ef 100644
--- a/common/socket.c
+++ b/common/socket.c
@@ -344,15 +344,14 @@ static uint32_t _in6_addr_scope(struct in6_addr* addr)
         return scope;
 }
 
-static int32_t _in6_addr_scope_id(struct in6_addr* addr)
+static int32_t _sockaddr_in6_scope_id(struct sockaddr_in6* addr)
 {
         int32_t res = -1;
-
         struct ifaddrs *ifaddr, *ifa;
         uint32_t addr_scope;
 
         /* get scope for requested address */
-        addr_scope = _in6_addr_scope(addr);
+        addr_scope = _in6_addr_scope(&addr->sin6_addr);
         if (addr_scope == 0) {
                 /* global scope doesn't need a specific scope id */
                 return addr_scope;
@@ -393,10 +392,29 @@ static int32_t _in6_addr_scope_id(struct in6_addr* addr)
                         continue;
                 }
 
-                /* use the scope id of this interface */
+                /* use if address is equal */
+                if (memcmp(&addr->sin6_addr.s6_addr, &addr_in->sin6_addr.s6_addr, sizeof(addr_in->sin6_addr.s6_addr)) == 0) {
+                        res = addr_in->sin6_scope_id;
+                        /* if scope id equals the requested one then assume it was valid */
+                        if (addr->sin6_scope_id == addr_in->sin6_scope_id) {
+                                break;
+                        } else {
+                                continue;
+                        }
+                }
+
+                /* skip loopback interface if not already matched exactly above */
+                if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) {
+                        continue;
+                }
+
+                /* set the scope id of this interface as most likely candidate */
                 res = addr_in->sin6_scope_id;
 
-                break;
+                /* if scope id equals the requested one then assume it was valid */
+                if (addr->sin6_scope_id == addr_in->sin6_scope_id) {
+                        break;
+                }
         }
 
         freeifaddrs(ifaddr);
@@ -442,7 +460,7 @@ int socket_connect_addr(struct sockaddr* addr, uint16_t port)
                  * a scope id from a suitable interface on this system or routing might
                  * fail. An IPv6 guru should have another look though...
                  */
-                addr_in->sin6_scope_id = _in6_addr_scope_id(&addr_in->sin6_addr);
+                addr_in->sin6_scope_id = _sockaddr_in6_scope_id(addr_in);
 
                 addrlen = sizeof(struct sockaddr_in6);
         }