From 257ab8de93312295d475638498c57e4de77a4b02 Mon Sep 17 00:00:00 2001
From: Brian Geffon <bgeffon@google.com>
Date: Tue, 22 May 2018 15:51:55 -0700
Subject: When sending a RST the acceptable ACK window shouldn't change.
Today when we transmit a RST it's happening during the time-wait
flow. Because a FIN is allowed to advance the acceptable ACK window
we're incorrectly doing that for a RST.
PiperOrigin-RevId: 197637565
Change-Id: I080190b06bd0225326cd68c1fbf37bd3fdbd414e
---
pkg/tcpip/transport/tcp/snd.go | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
(limited to 'pkg/tcpip')
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index 6c363a929..95bea4d88 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -342,15 +342,17 @@ func (s *sender) sendData() {
s.ep.mu.Lock()
// We're sending a FIN by default
fl := flagFin
+ segEnd = seg.sequenceNumber
if (s.ep.shutdownFlags&tcpip.ShutdownRead) != 0 && rcvBufUsed > 0 {
// If there is unread data we must send a RST.
// For more information see RFC 2525 section 2.17.
fl = flagRst
+ } else {
+ segEnd = seg.sequenceNumber.Add(1)
}
+
s.ep.mu.Unlock()
seg.flags |= uint8(fl)
-
- segEnd = seg.sequenceNumber.Add(1)
} else {
// We're sending a non-FIN segment.
if !seg.sequenceNumber.LessThan(end) {
--
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