Make sure the packet source MAC address is always set.

[tinc] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index e4b839e..6f72e05 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -454,6 +454,13 @@ bool receive_tcppacket_sptps(connection_t *c, const char *data, int len) {
                return true;
        }
 
+       if(!to->status.reachable) {
+               /* This can happen in the form of a race condition
+                  if the node just became unreachable. */
+               logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot relay TCP packet from %s (%s) because the destination, %s (%s), is unreachable", from->name, from->hostname, to->name, to->hostname);
+               return true;
+       }
+
        /* Help the sender reach us over UDP.
           Note that we only do this if we're the destination or the static relay;
           otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */
@@ -1245,8 +1252,12 @@ void send_packet(node_t *n, vpn_packet_t *packet) {
        // If it's for myself, write it to the tun/tap device.
 
        if(n == myself) {
-               if(overwrite_mac)
+               if(overwrite_mac) {
                         memcpy(DATA(packet), mymac.x, ETH_ALEN);
+                        // Use an arbitrary fake source address.
+                        memcpy(DATA(packet) + ETH_ALEN, DATA(packet), ETH_ALEN);
+                        DATA(packet)[ETH_ALEN * 2 - 1] ^= 0xFF;
+               }
                n->out_packets++;
                n->out_bytes += packet->len;
                devops.write(packet);
@@ -1461,6 +1472,13 @@ skip_harder:
                        return;
                }
 
+               if(!to->status.reachable) {
+                       /* This can happen in the form of a race condition
+                          if the node just became unreachable. */
+                       logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot relay packet from %s (%s) because the destination, %s (%s), is unreachable", from->name, from->hostname, to->name, to->hostname);
+                       return;
+               }
+
                /* The packet is supposed to come from the originator or its static relay
                   (i.e. with no dynamic relays in between).
                   If it did not, "help" the static relay by sending it UDP info.