From 7a58c510373afdffe56ec1ddc7c148f48e1abcf3 Mon Sep 17 00:00:00 2001
From: Jake Hillion <jake@hillion.co.uk>
Date: Mon, 22 Mar 2021 21:26:58 +0000
Subject: [PATCH] windowsize atomicity

---
 udp/congestion/newreno.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/udp/congestion/newreno.go b/udp/congestion/newreno.go
index 5f14fcd..4e94a41 100644
--- a/udp/congestion/newreno.go
+++ b/udp/congestion/newreno.go
@@ -260,11 +260,12 @@ func (c *NewReno) receivedAck(ack uint32) {
 
 	c.inFlight = c.inFlight[i:]
 	if c.slowStart {
-		c.windowSize += uint32(i)
+		atomic.AddUint32(&c.windowSize, uint32(i))
 	} else {
 		c.windowCount += uint32(i)
-		if c.windowCount > c.windowSize {
-			c.windowCount -= uint32(i)
+		s := c.windowSize
+		if c.windowCount > s {
+			c.windowCount -= s
 			atomic.AddUint32(&c.windowSize, 1)
 		}
 	}