Send gratuitous type 2 probe replies.

[tinc] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index 52c46e1..e9e2172 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -67,7 +67,7 @@ static void send_udppacket(node_t *, vpn_packet_t *);
 unsigned replaywin = 16;
 bool localdiscovery = true;
 bool udp_discovery = true;
-int udp_discovery_keepalive_interval = 9;
+int udp_discovery_keepalive_interval = 10;
 int udp_discovery_interval = 2;
 int udp_discovery_timeout = 30;
 
@@ -103,23 +103,22 @@ static void udp_probe_timeout_handler(void *data) {
 
 static void send_udp_probe_reply(node_t *n, vpn_packet_t *packet, length_t len) {
        if(!n->status.sptps && !n->status.validkey) {
-               // But not if we don't have his key.
-               logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request from %s (%s) but we don't have his key yet", n->name, n->hostname);
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP probe reply to %s (%s) but we don't have his key yet", n->name, n->hostname);
                return;
        }
 
-       logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname);
-
        /* Type 2 probe replies were introduced in protocol 17.3 */
        if ((n->options >> 24) >= 3) {
-               uint8_t *data = DATA(packet);
-               *data++ = 2;
+               DATA(packet)[0] = 2;
                uint16_t len16 = htons(len);
-               memcpy(data, &len16, 2);
+               memcpy(DATA(packet) + 1, &len16, 2);
                packet->len = MIN_PROBE_SIZE;
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Sending type 2 probe reply length %u to %s (%s)", len, n->name, n->hostname);
+
        } else {
                /* Legacy protocol: n won't understand type 2 probe replies. */
                DATA(packet)[0] = 1;
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Sending type 1 probe reply length %u to %s (%s)", len, n->name, n->hostname);
        }
 
        /* Temporarily set udp_confirmed, so that the reply is sent
@@ -133,7 +132,7 @@ static void send_udp_probe_reply(node_t *n, vpn_packet_t *packet, length_t len)
 
 static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
        if(!DATA(packet)[0]) {
-               /* It's a probe request, send back a reply */
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname);
                return send_udp_probe_reply(n, packet, len);
        }
 
@@ -151,6 +150,9 @@ static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
           packet used. */
        n->status.udp_confirmed = true;
 
+       // Reset the UDP ping timer.
+       n->udp_ping_sent = now;
+
        if(udp_discovery) {
                timeout_del(&n->udp_ping_timeout);
                timeout_add(&n->udp_ping_timeout, &udp_probe_timeout_handler, n, &(struct timeval){udp_discovery_timeout, 0});
@@ -281,7 +283,11 @@ static bool receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
                        return false;
                }
                inpkt->offset += 2 * sizeof(node_id_t);
-               if(!sptps_receive_data(&n->sptps, DATA(inpkt), inpkt->len - 2 * sizeof(node_id_t))) {
+               n->status.udppacket = true;
+               bool result = sptps_receive_data(&n->sptps, DATA(inpkt), inpkt->len - 2 * sizeof(node_id_t));
+               n->status.udppacket = false;
+
+               if(!result) {
                        logger(DEBUG_TRAFFIC, LOG_ERR, "Got bad packet from %s (%s)", n->name, n->hostname);
                        return false;
                }
@@ -765,8 +771,14 @@ bool receive_sptps_record(void *handle, uint8_t type, const void *data, uint16_t
        inpkt.offset = DEFAULT_PACKET_OFFSET;
 
        if(type == PKT_PROBE) {
+               if(!from->status.udppacket) {
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Got SPTPS PROBE packet from %s (%s) via TCP", from->name, from->hostname);
+                       return false;
+               }
                inpkt.len = len;
                memcpy(DATA(&inpkt), data, len);
+               if(inpkt.len > from->maxrecentlen)
+                       from->maxrecentlen = inpkt.len;
                udp_probe_h(from, &inpkt, len);
                return true;
        }
@@ -818,6 +830,9 @@ bool receive_sptps_record(void *handle, uint8_t type, const void *data, uint16_t
                }
        }
 
+       if(from->status.udppacket && inpkt.len > from->maxrecentlen)
+               from->maxrecentlen = inpkt.len;
+
        receive_packet(from, &inpkt);
        return true;
 }
@@ -862,6 +877,28 @@ static void try_udp(node_t* n) {
        if(!udp_discovery)
                return;
 
+       /* Send gratuitous probe replies to 1.1 nodes. */
+
+       if((n->options >> 24) >= 3 && n->status.udp_confirmed) {
+               struct timeval ping_tx_elapsed;
+               timersub(&now, &n->udp_reply_sent, &ping_tx_elapsed);
+
+               if(ping_tx_elapsed.tv_sec >= udp_discovery_keepalive_interval - 1) {
+                       n->udp_reply_sent = now;
+                       if(n->maxrecentlen) {
+                               vpn_packet_t pkt;
+                               pkt.len = n->maxrecentlen;
+                               pkt.offset = DEFAULT_PACKET_OFFSET;
+                               memset(DATA(&pkt), 0, 14);
+                               randomize(DATA(&pkt) + 14, MIN_PROBE_SIZE - 14);
+                               send_udp_probe_reply(n, &pkt, pkt.len);
+                               n->maxrecentlen = 0;
+                       }
+               }
+       }
+
+       /* Probe request */
+
        struct timeval ping_tx_elapsed;
        timersub(&now, &n->udp_ping_sent, &ping_tx_elapsed);