diff options
| author | Simon Baatz <gmbnomis@gmail.com> | 2026-03-16 21:51:10 +0300 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-03-19 12:26:25 +0300 |
| commit | 96a584db75bb21781562dc79f11932ce38a1205f (patch) | |
| tree | 3bb2b8a35b9772b2c5602f829d5fdd6e7adc7c72 | |
| parent | a7fb05cbb8f989fa5a81818be9680464cff9d717 (diff) | |
| download | linux-96a584db75bb21781562dc79f11932ce38a1205f.tar.xz | |
selftests/net: packetdrill: improve tcp_rcv_neg_window.pkt
The test depends on accepting a packet that is larger than the
advertised window and that does not trigger an immediate ACK.
Previously, the test might still pass even if kernel behavior changed
unexpectedly. Add assertions verifying that the large packet was
accepted and no ACK was sent.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Link: https://patch.msgid.link/20260316-improve_tcp_neg_usable_wnd_test-v1-1-f16d5e365107@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window.pkt | 14 |
1 files changed, 11 insertions, 3 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 index 15a9b4938f16..b9ab264b2a11 100644 --- a/tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window.pkt +++ b/tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window.pkt @@ -1,4 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 +// Test maximum advertised window limit when rcv_nxt advances past +// rcv_mwnd_seq. The "usable window" must be properly clamped to zero +// rather than becoming negative. --mss=1000 @@ -17,10 +20,15 @@ +0 accept(3, ..., ...) = 4 -// A too big packet is accepted if the receive queue is empty +// A too big packet is accepted if the receive queue is empty. It +// does not trigger an immediate ACK. +0 < P. 1:20001(20000) ack 1 win 257 + +0 %{ assert tcpi_bytes_received == 20000, tcpi_bytes_received; }% + // 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 }% - +// Verify that the RST was accepted. Indirectly this also verifies that no +// immediate ACK was sent for the data packet above. + +0 < . 20001:20001(0) ack 1 win 257 + +0 > R 1:1(0) |