X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fnet_packet.c;h=d700fd6b7502c34fb686e5df5bd473773408240c;hp=4bbb2d6f16e560bd5911addf946b8ca379d713fc;hb=e3c763eae89df9a69bb2d611238ef18f78de311f;hpb=e3a4672afb8eb341b380e74b2bf6d098f61c08a3

diff --git a/src/net_packet.c b/src/net_packet.c
index 4bbb2d6f..d700fd6b 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -179,12 +179,20 @@ void send_mtu_probe(node_t *n) {
 }
 
 static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
-	logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
-
 	if(!packet->data[0]) {
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe request %d from %s (%s)", packet->len, n->name, n->hostname);
+
 		/* It's a probe request, send back a reply */
 
-		packet->data[0] = 1;
+		/* Type 2 probe replies were introduced in protocol 17.3 */
+		if ((n->options >> 24) == 3) {
+			uint8_t* data = packet->data;
+			*data++ = 2;
+			uint16_t len16 = htons(len); memcpy(data, &len16, 2); data += 2;
+		} else {
+			/* Legacy protocol: n won't understand type 2 probe replies. */
+			packet->data[0] = 1;
+		}
 
 		/* Temporarily set udp_confirmed, so that the reply is sent
 		   back exactly the way it came in. */
@@ -194,6 +202,16 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 		send_udppacket(n, packet);
 		n->status.udp_confirmed = udp_confirmed;
 	} else {
+		length_t probelen = len;
+		if (packet->data[0] == 2) {
+			if (len < 3)
+				logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) MTU probe reply from %s (%s)", n->name, n->hostname);
+			else {
+				uint16_t probelen16; memcpy(&probelen16, packet->data + 1, 2); probelen = ntohs(probelen16);
+			}
+		}
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d MTU probe reply %d from %s (%s)", packet->data[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. */
@@ -203,7 +221,7 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 		/* If we haven't established the PMTU yet, restart the discovery process. */
 
 		if(n->mtuprobes > 30) {
-			if (len == n->maxmtu + 8) {
+			if (probelen == n->maxmtu + 8) {
 				logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
 				n->maxmtu = MTU;
 				n->mtuprobes = 10;
@@ -218,10 +236,10 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 
 		/* If applicable, raise the minimum supported MTU */
 
-		if(len > n->maxmtu)
-			len = n->maxmtu;
-		if(n->minmtu < len)
-			n->minmtu = len;
+		if(probelen > n->maxmtu)
+			probelen = n->maxmtu;
+		if(n->minmtu < probelen)
+			n->minmtu = probelen;
 
 		/* Calculate RTT and bandwidth.
 		   The RTT is the time between the MTU probe burst was sent and the first
@@ -238,7 +256,7 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 			n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
 			n->probe_time = now;
 		} else if(n->probe_counter == 3) {
-			n->bandwidth = 2.0 * len / (diff.tv_sec + diff.tv_usec * 1e-6);
+			n->bandwidth = 2.0 * probelen / (diff.tv_sec + diff.tv_usec * 1e-6);
 			logger(DEBUG_TRAFFIC, LOG_DEBUG, "%s (%s) RTT %.2f ms, burst bandwidth %.3f Mbit/s, rx packet loss %.2f %%", n->name, n->hostname, n->rtt * 1e3, n->bandwidth * 8e-6, n->packetloss * 1e2);
 		}
 	}