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| author | Simon Baatz <gmbnomis@gmail.com> | 2026-03-09 11:02:31 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-03-14 18:02:51 +0300 |
| commit | 3eb371eddad0a47183dd4434de9c9190d0f721c5 (patch) | |
| tree | 05110a05efb4bacc1c87491ef69ef50eea499dc2 /tools | |
| parent | ba58b3e70b86cd64fe8bb9c52f1111667a448908 (diff) | |
| download | linux-3eb371eddad0a47183dd4434de9c9190d0f721c5.tar.xz | |
selftests/net: packetdrill: add tcp_rcv_neg_window.pkt
The test ensures we correctly apply the maximum advertised window limit
when rcv_nxt advances past rcv_mwnd_seq, so that the "usable window"
is properly clamped to zero rather than becoming negative.
Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260309-tcp_rfc7323_retract_wnd_rfc-v3-6-4c7f96b1ec69@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window.pkt | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window.pkt b/tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window.pkt new file mode 100644 index 000000000000..15a9b4938f16 --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window.pkt @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 + +--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 win 18980 <mss 1460,nop,wscale 0> + +.1 < . 1:1(0) ack 1 win 257 + + +0 accept(3, ..., ...) = 4 + +// A too big packet is accepted if the receive queue is empty + +0 < P. 1:20001(20000) ack 1 win 257 +// Send a RST immediately so that there is no rcv_wup/rcv_mwnd_seq update yet + +0 < R. 20001:20001(0) ack 1 win 257 + + +.1 %{ assert tcpi_state == TCP_CLOSE, tcpi_state }% + |