X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fnet_packet.c;h=e50135ec42f264c026e6ca7a293da5ba9f875156;hb=d30b9e1272fef18070d37d10b2b3e4bb2fc07f59;hp=dbf361fd38fe2c41b4484763045d266545c7be84;hpb=f57129ce3439f3826c12f15feb5df05e5ad8cab9;p=tinc

diff --git a/src/net_packet.c b/src/net_packet.c
index dbf361fd..e50135ec 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -164,11 +164,26 @@ 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]) {
+		/* It's a probe request, send back a reply */
+
 		packet->data[0] = 1;
+
+		/* 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;
 	} else {
+		/* 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;
 
+		/* If we haven't established the PMTU yet, restart the discovery process. */
+
 		if(n->mtuprobes > 30) {
 			if(n->minmtu)
 				n->mtuprobes = 30;
@@ -176,6 +191,8 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 				n->mtuprobes = 1;
 		}
 
+		/* If applicable, raise the minimum supported MTU */
+
 		if(len > n->maxmtu)
 			len = n->maxmtu;
 		if(n->minmtu < len)
@@ -447,24 +464,28 @@ static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock
 	if(n->status.udp_confirmed)
 		return;
 
-	/* Otherwise, go through the list of known addresses of
-	   this node. The first address we try is always the
-	   one in n->address; that could be set to the node's
-	   reflexive UDP address discovered during key
-	   exchange. The other known addresses are those found
-	   in edges to this node. */
+	/* Send every third packet to n->address; that could be set
+	   to the node's reflexive UDP address discovered during key
+	   exchange. */
 
+	static int x = 0;
+	if(++x >= 3) {
+		x = 0;
+		return;
+	}
+
+	/* Otherwise, address are found in edges to this node.
+	   So we pick a random edge and a random socket. */
 
 	int i = 0;
 	int j = rand() % n->edge_tree->count;
 	edge_t *candidate = NULL;
 
-	for splay_each(edge_t, e, edge_weight_tree) {
-		if(e->to != n)
-			continue;
-		i++;
-		if(!candidate || i == j)
-			candidate = e;
+	for splay_each(edge_t, e, n->edge_tree) {
+		if(i++ == j) {
+			candidate = e->reverse;
+			break;
+		}
 	}
 
 	if(candidate) {