X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fnet_packet.c;h=9bebca43f568656cfb0f34a91c64013a420e5dc5;hb=1b972f22733dc979568bc0ad8ebe0c711887e447;hp=5976fc266933b4d15f7feb70252aa37e16122668;hpb=97cf4783188b8027d2309ce594fea5fc6daf31d1;p=tinc

diff --git a/src/net_packet.c b/src/net_packet.c
index 5976fc26..9bebca43 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -65,6 +65,21 @@ int udp_discovery_timeout = 30;
 
 #define MAX_SEQNO 1073741824
 
+static void try_fix_mtu(node_t *n) {
+	if(n->mtuprobes < 0)
+		return;
+
+	if(n->mtuprobes == 90 || n->minmtu >= n->maxmtu) {
+		if(n->minmtu > n->maxmtu)
+			n->minmtu = n->maxmtu;
+		else
+			n->maxmtu = n->minmtu;
+		n->mtu = n->minmtu;
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
+		n->mtuprobes = -1;
+	}
+}
+
 static void udp_probe_timeout_handler(void *data) {
 	node_t *n = data;
 	if(!n->status.udp_confirmed)
@@ -129,7 +144,7 @@ static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 		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;
+			n->mtuprobes = 30;
 			return;
 		}
 
@@ -137,8 +152,10 @@ static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 
 		if(probelen > n->maxmtu)
 			probelen = n->maxmtu;
-		if(n->minmtu < probelen)
+		if(n->minmtu < probelen) {
 			n->minmtu = probelen;
+			try_fix_mtu(n);
+		}
 
 		/* Calculate RTT and bandwidth.
 		   The RTT is the time between the MTU probe burst was sent and the first
@@ -164,7 +181,7 @@ static void udp_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 = probe_timestamp;
 		} else if(n->probe_counter == 3) {
-			/* TODO: this will never fire after initial MTU discovery. */
+			/* TODO: this will never fire - we're not sending batches of three anymore. */
 			struct timeval probe_timestamp_diff;
 			timersub(&probe_timestamp, &n->probe_time, &probe_timestamp_diff);
 			n->bandwidth = 2.0 * probelen / (probe_timestamp_diff.tv_sec + probe_timestamp_diff.tv_usec * 1e-6);
@@ -658,6 +675,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 				n->maxmtu = origlen - 1;
 			if(n->mtu >= origlen)
 				n->mtu = origlen - 1;
+			try_fix_mtu(n);
 		} else
 			logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
 	}
@@ -722,6 +740,7 @@ static bool send_sptps_data_priv(node_t *to, node_t *from, int type, const void
 				relay->maxmtu = len - 1;
 			if(relay->mtu >= len)
 				relay->mtu = len - 1;
+			try_fix_mtu(relay);
 		} else {
 			logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", relay->name, relay->hostname, sockstrerror(sockerrno));
 			return false;
@@ -884,49 +903,40 @@ static void try_mtu(node_t *n) {
 		return;
 	}
 
-	/* mtuprobes == 0..29: initial discovery, send bursts with 1 second interval, mtuprobes++
-	   mtuprobes ==    30: fix MTU, and go to 31
-	   mtuprobes ==    31: send one >maxmtu probe every pingtimeout */
+	/* mtuprobes == 0..89: initial discovery, send bursts with 1 second interval, mtuprobes++
+	   mtuprobes ==    90: fix MTU, and go to -1
+	   mtuprobes ==    -1: send one >maxmtu probe every pingtimeout */
 
 	struct timeval now;
 	gettimeofday(&now, NULL);
 	struct timeval elapsed;
 	timersub(&now, &n->probe_sent_time, &elapsed);
-	if(n->mtuprobes < 31) {
-		if(n->mtuprobes != 0 && elapsed.tv_sec < 1)
+	if(n->mtuprobes >= 0) {
+		if(n->mtuprobes != 0 && elapsed.tv_sec == 0 && elapsed.tv_usec < 333333)
 			return;
 	} else {
 		if(elapsed.tv_sec < pingtimeout)
 			return;
 	}
 
-	if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
-		if(n->minmtu > n->maxmtu)
-			n->minmtu = n->maxmtu;
-		else
-			n->maxmtu = n->minmtu;
-		n->mtu = n->minmtu;
-		logger(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
-		n->mtuprobes = 31;
-	}
+	try_fix_mtu(n);
 
 	int timeout;
-	if(n->mtuprobes == 31) {
+	if(n->mtuprobes < 0) {
 		/* After the initial discovery, we only send one >maxmtu probe
 		   to detect PMTU increases. */
 		if(n->maxmtu + 8 < MTU)
 			send_udp_probe_packet(n, n->maxmtu + 8);
 	} else {
-		/* Probes are sent in batches of three, with random sizes between the
+		/* Probes are sent with random sizes between the
 		   lower and upper boundaries for the MTU thus far discovered. */
-		for (int i = 0; i < 3; i++) {
-			int len = n->maxmtu;
-			if(n->minmtu < n->maxmtu)
-				len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+		int len = n->maxmtu;
+		if(n->minmtu < n->maxmtu)
+			len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+		send_udp_probe_packet(n, MAX(len, 64));
 
-			send_udp_probe_packet(n, MAX(len, 64));
-		}
-		n->mtuprobes++;
+		if(n->mtuprobes >= 0)
+			n->mtuprobes++;
 	}
 
 	n->probe_counter = 0;