X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fnet_packet.c;h=e9e2172c67f8ef6a5d44c3dc4d15312807d61cc5;hb=ae5b56c03d1e1af7561d7f1d1d8a333c3a9691ff;hp=96f8f10e7b645a5364687671b357146cfc7f6544;hpb=f0afde0467443969eb408090d6b8ee542768ee33;p=tinc

diff --git a/src/net_packet.c b/src/net_packet.c
index 96f8f10e..e9e2172c 100644
--- 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;
 
@@ -101,75 +101,81 @@ static void udp_probe_timeout_handler(void *data) {
 	n->maxmtu = MTU;
 }
 
-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 */
+static void send_udp_probe_reply(node_t *n, vpn_packet_t *packet, length_t len) {
+	if(!n->status.sptps && !n->status.validkey) {
+		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;
+	}
 
-		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);
-			return;
-		}
+	/* Type 2 probe replies were introduced in protocol 17.3 */
+	if ((n->options >> 24) >= 3) {
+		DATA(packet)[0] = 2;
+		uint16_t len16 = htons(len);
+		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
+	   back exactly the way it came in. */
 
+	bool udp_confirmed = n->status.udp_confirmed;
+	n->status.udp_confirmed = true;
+	send_udppacket(n, packet);
+	n->status.udp_confirmed = udp_confirmed;
+}
+
+static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
+	if(!DATA(packet)[0]) {
 		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);
+	}
 
-		/* Type 2 probe replies were introduced in protocol 17.3 */
-		if ((n->options >> 24) >= 3) {
-			uint8_t *data = DATA(packet);
-			*data++ = 2;
-			uint16_t len16 = htons(len); memcpy(data, &len16, 2); data += 2;
-			packet->len = MIN_PROBE_SIZE;
-		} else {
-			/* Legacy protocol: n won't understand type 2 probe replies. */
-			DATA(packet)[0] = 1;
-		}
+	if (DATA(packet)[0] == 2) {
+		// It's a type 2 probe reply, use the length field inside the packet
+		uint16_t len16;
+		memcpy(&len16, DATA(packet) + 1, 2);
+		len = ntohs(len16);
+	}
 
-		/* Temporarily set udp_confirmed, so that the reply is sent
-		   back exactly the way it came in. */
+	logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], len, n->name, n->hostname);
 
-		bool udp_confirmed = n->status.udp_confirmed;
-		n->status.udp_confirmed = true;
-		send_udppacket(n, packet);
-		n->status.udp_confirmed = udp_confirmed;
-	} else {
-		length_t probelen = len;
-		if (DATA(packet)[0] == 2) {
-			if (len < 3)
-				logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) UDP probe reply from %s (%s)", n->name, n->hostname);
-			else {
-				uint16_t probelen16; memcpy(&probelen16, DATA(packet) + 1, 2); probelen = ntohs(probelen16);
-			}
-		}
-		logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], probelen, n->name, n->hostname);
+	/* It's a valid reply: now we know bidirectional communication
+	   is possible using the address and socket that the reply
+	   packet used. */
+	n->status.udp_confirmed = true;
 
-		/* It's a valid reply: now we know bidirectional communication
-		   is possible using the address and socket that the reply
-		   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});
-		}
+	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});
+	}
 
-		if(probelen > n->maxmtu) {
-			logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
-			n->minmtu = probelen;
-			n->maxmtu = MTU;
-			/* Set mtuprobes to 1 so that try_mtu() doesn't reset maxmtu */
-			n->mtuprobes = 1;
-			return;
-		} else if(n->mtuprobes < 0 && probelen == n->maxmtu) {
-			/* We got a maxmtu sized packet, confirming the PMTU is still valid. */
-			n->mtuprobes = -1;
-		}
+	if(len > n->maxmtu) {
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
+		n->minmtu = len;
+		n->maxmtu = MTU;
+		/* Set mtuprobes to 1 so that try_mtu() doesn't reset maxmtu */
+		n->mtuprobes = 1;
+		return;
+	} else if(n->mtuprobes < 0 && len == n->maxmtu) {
+		/* We got a maxmtu sized packet, confirming the PMTU is still valid. */
+		n->mtuprobes = -1;
+		n->mtu_ping_sent = now;
+	}
 
-		/* If applicable, raise the minimum supported MTU */
+	/* If applicable, raise the minimum supported MTU */
 
-		if(n->minmtu < probelen) {
-			n->minmtu = probelen;
-			try_fix_mtu(n);
-		}
+	if(n->minmtu < len) {
+		n->minmtu = len;
+		try_fix_mtu(n);
 	}
 }
 
@@ -277,7 +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;
 		}
@@ -761,8 +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;
 	}
@@ -814,6 +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;
 }
@@ -858,6 +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);