From: Simon Baatz <[email protected]> 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 <[email protected]> --- .../net/packetdrill/tcp_rcv_neg_window.pkt | 26 ++++++++++++++++++++++ 1 file changed, 26 insertions(+) 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 0000000000000000000000000000000000000000..15a9b4938f16d175ac54f3fd192ed2b59b0a4399 --- /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 }% + -- 2.53.0
