From e4202fe9a6d2be71523c8fdb7fdfc003b423d7e6 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@meshlink.io>
Date: Mon, 18 May 2020 20:34:54 +0200
Subject: [PATCH] Don't start RTT measurements for unreliable channels.

We are not getting ACKs back, and the RTT value is not used for unreliable
channels anyway.
---
 src/utcp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/utcp.c b/src/utcp.c
index f81150bf..dc5a2fcf 100644
--- a/src/utcp.c
+++ b/src/utcp.c
@@ -719,7 +719,7 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
 			pkt->hdr.ctl |= FIN;
 		}
 
-		if(!c->rtt_start.tv_sec) {
+		if(!c->rtt_start.tv_sec && is_reliable(c)) {
 			// Start RTT measurement
 			clock_gettime(UTCP_CLOCK, &c->rtt_start);
 			c->rtt_seq = pkt->hdr.seq + seglen;
-- 
2.39.5