Use edge local addresses for local discovery.

[tinc] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index f69bf98..6d41747 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -144,14 +144,14 @@ static void send_mtu_probe_handler(void *data) {
                randomize(packet.data + 14, len - 14);
                packet.len = len;
                packet.priority = 0;
-               n->status.broadcast = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
+               n->status.send_locally = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
 
                logger(DEBUG_TRAFFIC, LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
 
                send_udppacket(n, &packet);
        }
 
-       n->status.broadcast = false;
+       n->status.send_locally = false;
        n->probe_counter = 0;
        gettimeofday(&n->probe_time, NULL);
 
@@ -544,6 +544,18 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
        return;
 }
 
+static void adapt_socket(const sockaddr_t *sa, int *sock) {
+       /* Make sure we have a suitable socket for the chosen address */
+       if(listen_socket[*sock].sa.sa.sa_family != sa->sa.sa_family) {
+               for(int i = 0; i < listen_sockets; i++) {
+                       if(listen_socket[i].sa.sa.sa_family == sa->sa.sa_family) {
+                               *sock = i;
+                               break;
+                       }
+               }
+       }
+}
+
 static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock) {
        /* Latest guess */
        *sa = &n->address;
@@ -582,18 +594,32 @@ static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock
                *sock = rand() % listen_sockets;
        }
 
-       /* Make sure we have a suitable socket for the chosen address */
-       if(listen_socket[*sock].sa.sa.sa_family != (*sa)->sa.sa_family) {
-               for(int i = 0; i < listen_sockets; i++) {
-                       if(listen_socket[i].sa.sa.sa_family == (*sa)->sa.sa_family) {
-                               *sock = i;
-                               break;
-                       }
+       adapt_socket(*sa, sock);
+}
+
+static void choose_local_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+       /* Pick one of the edges from this node at random, then use its local address. */
+
+       int i = 0;
+       int j = rand() % n->edge_tree->count;
+       edge_t *candidate = NULL;
+
+       for splay_each(edge_t, e, n->edge_tree) {
+               if(i++ == j) {
+                       candidate = e;
+                       break;
                }
        }
-}
 
-static void choose_broadcast_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+       if (candidate && candidate->local_address.sa.sa_family) {
+               *sa = &candidate->local_address;
+               *sock = rand() % listen_sockets;
+               adapt_socket(*sa, sock);
+               return;
+       }
+
+       /* No candidate? Use broadcasts instead. */
+
        static sockaddr_t broadcast_ipv4 = {
                .in = {
                        .sin_family = AF_INET,
@@ -733,8 +759,8 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        const sockaddr_t *sa;
        int sock;
 
-       if(n->status.broadcast)
-               choose_broadcast_address(n, &sa, &sock);
+       if(n->status.send_locally)
+               choose_local_address(n, &sa, &sock);
        else
                choose_udp_address(n, &sa, &sock);
 
@@ -785,8 +811,8 @@ bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
        const sockaddr_t *sa;
        int sock;
 
-       if(to->status.broadcast)
-               choose_broadcast_address(to, &sa, &sock);
+       if(to->status.send_locally)
+               choose_local_address(to, &sa, &sock);
        else
                choose_udp_address(to, &sa, &sock);