Commit 74511332 authored by Simon Baatz's avatar Simon Baatz Committed by Jakub Kicinski
Browse files

selftests/net: packetdrill: Verify acceptance of FIN packets when RWIN is 0 



Add a packetdrill test that verifies we accept bare FIN packets when
the advertised receive window is zero.

Signed-off-by: default avatarSimon Baatz <gmbnomis@gmail.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260224-fix_zero_wnd_fin-v2-2-a16677ea7cea@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1e3bb184

tools/testing/selftests/net/packetdrill/tcp_rcv_zero_wnd_fin.pkt

0 → 100644
+27 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



// Some TCP stacks send FINs even though the window is closed. We break

// a possible FIN/ACK loop by accepting the FIN.



--mss=1000



`./defaults.sh`



// Establish a connection.

   +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3

   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0

   +0 setsockopt(3, SOL_SOCKET, SO_RCVBUF, [20000], 4) = 0

   +0 bind(3, ..., ...) = 0

   +0 listen(3, 1) = 0



   +0 < S 0:0(0) win 32792 <mss 1000,nop,wscale 7>

   +0 > S. 0:0(0) ack 1 <mss 1460,nop,wscale 0>

   +0 < . 1:1(0) ack 1 win 257



   +0 accept(3, ..., ...) = 4



   +0 < P. 1:60001(60000) ack 1 win 257

    * > .  1:1(0) ack 60001 win 0



   +0 < F. 60001:60001(0) ack 1 win 257

   +0 > . 1:1(0) ack 60002 win 0