From: Simon Baatz <[email protected]> This test verifies the sequence number checks using the maximum advertised window sequence number. Cases:
1. The window is reduced to zero because of memory 2. The window grows again but still does not reach the originally advertised window Signed-off-by: Simon Baatz <[email protected]> --- .../net/packetdrill/tcp_rcv_wnd_shrink_nomem.pkt | 109 +++++++++++++++++++++ 1 file changed, 109 insertions(+) diff --git a/tools/testing/selftests/net/packetdrill/tcp_rcv_wnd_shrink_nomem.pkt b/tools/testing/selftests/net/packetdrill/tcp_rcv_wnd_shrink_nomem.pkt new file mode 100644 index 0000000000000000000000000000000000000000..cd761300d02df449ff68cd6ff6f3b8ac62d5f27b --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_rcv_wnd_shrink_nomem.pkt @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 + +--mss=1000 + +`./defaults.sh +sysctl -q net.ipv4.tcp_rmem="4096 32768 $((32*1024*1024))"` + + 0 `nstat -n` + +// Establish a connection. + +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 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 10> + +0 < . 1:1(0) ack 1 win 257 + + +0 accept(3, ..., ...) = 4 + + +0 < P. 1:10001(10000) ack 1 win 257 + * > . 1:1(0) ack 10001 win 16 + +// Segments smaller than the window scale factor do not allow to reduce the adv. window + +0 < P. 10001:11024(1023) ack 1 win 257 + * > . 1:1(0) ack 11024 win 16 + +0 < P. 11024:12047(1023) ack 1 win 257 + * > . 1:1(0) ack 12047 win 16 + +0 < P. 12047:13070(1023) ack 1 win 257 + * > . 1:1(0) ack 13070 win 16 + +0 < P. 13070:14093(1023) ack 1 win 257 + * > . 1:1(0) ack 14093 win 16 + +0 < P. 14093:15116(1023) ack 1 win 257 + * > . 1:1(0) ack 15116 win 16 + +0 < P. 15116:16139(1023) ack 1 win 257 + * > . 1:1(0) ack 16139 win 16 + +0 < P. 16139:17162(1023) ack 1 win 257 + * > . 1:1(0) ack 17162 win 16 + +0 < P. 17162:18185(1023) ack 1 win 257 + * > . 1:1(0) ack 18185 win 16 + +0 < P. 18185:19208(1023) ack 1 win 257 + * > . 1:1(0) ack 19208 win 16 + +0 < P. 19208:20231(1023) ack 1 win 257 + * > . 1:1(0) ack 20231 win 16 + +0 < P. 20231:21254(1023) ack 1 win 257 + * > . 1:1(0) ack 21254 win 16 + +0 < P. 21254:22277(1023) ack 1 win 257 + * > . 1:1(0) ack 22277 win 16 + +0 < P. 22277:23300(1023) ack 1 win 257 + * > . 1:1(0) ack 23300 win 16 + +0 < P. 23300:24323(1023) ack 1 win 257 + * > . 1:1(0) ack 24323 win 16 + +0 < P. 24323:25346(1023) ack 1 win 257 + * > . 1:1(0) ack 25346 win 16 + +0 < P. 25346:26369(1023) ack 1 win 257 + * > . 1:1(0) ack 26369 win 16 + +0 < P. 26369:27392(1023) ack 1 win 257 + * > . 1:1(0) ack 27392 win 16 + +0 < P. 27392:28415(1023) ack 1 win 257 + * > . 1:1(0) ack 28415 win 16 + +0 < P. 28415:29438(1023) ack 1 win 257 + * > . 1:1(0) ack 29438 win 16 + +0 < P. 29438:30461(1023) ack 1 win 257 + * > . 1:1(0) ack 30461 win 16 + +0 < P. 30461:31484(1023) ack 1 win 257 + * > . 1:1(0) ack 31484 win 16 + +0 < P. 31484:32507(1023) ack 1 win 257 + * > . 1:1(0) ack 32507 win 16 + +0 < P. 32507:33530(1023) ack 1 win 257 + * > . 1:1(0) ack 33530 win 16 + +// rcv buffer out of memory + +0 < P. 33530:49914(16384) ack 1 win 257 + +0 > . 1:1(0) ack 33530 win 0 + +// max window seq advertised 33530 + 16*1024 = 49914 + + +0 write(4, ..., 1000) = 1000 + +0 > P. 1:1001(1000) ack 33530 win 0 + +// LINUX_MIB_BEYOND_WINDOW: segment is beyond the max window sequence + +0 < . 49915:49915(0) ack 1001 win 257 + +0 > . 1001:1001(0) ack 33530 win 0 + + +0 < . 49914:49914(0) ack 1001 win 257 + + +0 %{ +assert tcpi_bytes_acked == 1000, tcpi_bytes_acked +}% + + +0 read(4, ..., 10000) = 10000 + +0 > . 1001:1001(0) ack 33530 win 9 + + +0 write(4, ..., 1000) = 1000 + +0 > P. 1001:2001(1000) ack 33530 win 9 + + // advertise right edge is 33530 + 9*1024 = 42746, but we still need to regard our maximum offer 49914 as in window + +0 < . 49914:49914(0) ack 2001 win 257 + + +0 %{ +assert tcpi_bytes_acked == 2000, tcpi_bytes_acked +}% + + +0 < P. 33530:42746(9216) ack 2001 win 257 + * > . 2001:2001(0) ack 42746 win 0 + +// Check LINUX_MIB_BEYOND_WINDOW has been incremented once + +0 `nstat | grep TcpExtBeyondWindow | grep -q " 1 "` -- 2.52.0
