From ee9e6a3c6b697b25445fa93fd6bffc1a91e03e07 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Thu, 20 Nov 2014 13:20:16 -0800
Subject: Change path selection logic to exclude non-fixed and non-active paths
 -- possible fix for "NAT traversal coma" issue. Also fix a typo.

---
 node/Peer.cpp | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'node')

diff --git a/node/Peer.cpp b/node/Peer.cpp
index 209de949..181761a8 100644
--- a/node/Peer.cpp
+++ b/node/Peer.cpp
@@ -176,6 +176,25 @@ Path::Type Peer::send(const RuntimeEnvironment *RR,const void *data,unsigned int
 		}
 	}
 
+	Path *bestPath = (Path *)0;
+	uint64_t normalPathAge = now - bestNormalPathLastReceived;
+	uint64_t tcpOutPathAge = now - bestTcpOutPathLastReceived;
+	if (normalPathAge < ZT_PEER_PATH_ACTIVITY_TIMEOUT) {
+		/* If we have a normal path that looks alive, only use TCP if it looks
+		 * even more alive, if the UDP path is not a very recent acquisition,
+		 * and if TCP tunneling is globally enabled. */
+		bestPath = ( (tcpOutPathAge < normalPathAge) && (normalPathAge > (ZT_PEER_DIRECT_PING_DELAY / 4)) && (RR->tcpTunnelingEnabled) ) ? bestTcpOutPath : bestNormalPath;
+	} else if ( (tcpOutPathAge < ZT_PEER_PATH_ACTIVITY_TIMEOUT) || ((RR->tcpTunnelingEnabled)&&(bestTcpOutPath)) ) {
+		/* Otherwise use a TCP path if we have an active one or if TCP
+		 * fallback has been globally triggered and we know of one at all. */
+		bestPath = bestTcpOutPath;
+	} else if ( (bestNormalPath) && (bestNormalPath->fixed()) ) {
+		/* Finally, use a normal path if we have a "fixed" one as these are
+		 * always considered basically alive. */
+		bestPath = bestNormalPath;
+	}
+
+	/* Old path choice logic -- would attempt to use inactive paths... deprecating and will probably kill.
 	Path *bestPath = (Path *)0;
 	if (bestTcpOutPath) { // we have a TCP out path
 		if (bestNormalPath) { // we have both paths, decide which to use
@@ -192,6 +211,8 @@ Path::Type Peer::send(const RuntimeEnvironment *RR,const void *data,unsigned int
 	} else { // we only have a normal path (or none at all, that case is caught below)
 		bestPath = bestNormalPath;
 	}
+	*/
+
 	if (!bestPath)
 		return Path::PATH_TYPE_NULL;
 
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