+ cinfo = tunnel_get_neighbor_fc(t, peer);
+ if (NULL == cinfo)
+ {
+ GNUNET_break (0);
+ return GNUNET_OK;
+ }
+
+ if (cinfo->bck_pid == pid)
+ {
+ /* already seen this packet, drop */
+ GNUNET_STATISTICS_update (stats, "# duplicate PID drops BCK", 1, GNUNET_NO);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ " Already seen pid %u, DROPPING!\n", pid);
+ tunnel_send_bck_ack (t, GNUNET_MESSAGE_TYPE_MESH_ACK);
+ return GNUNET_OK;
+ }
+
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ " pid %u not seen yet, forwarding\n", pid);
+ cinfo->bck_pid = pid;
+