1// SPDX-License-Identifier: GPL-2.0 2// Test maximum advertised window limit when rcv_nxt advances past 3// rcv_mwnd_seq. The "usable window" must be properly clamped to zero 4// rather than becoming negative. 5 6--mss=1000 7 8`./defaults.sh` 9 10// Establish a connection. 11 +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 12 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 13 +0 setsockopt(3, SOL_SOCKET, SO_RCVBUF, [20000], 4) = 0 14 +0 bind(3, ..., ...) = 0 15 +0 listen(3, 1) = 0 16 17 +0 < S 0:0(0) win 32792 <mss 1000,nop,wscale 7> 18 +0 > S. 0:0(0) ack 1 win 18980 <mss 1460,nop,wscale 0> 19 +.1 < . 1:1(0) ack 1 win 257 20 21 +0 accept(3, ..., ...) = 4 22 23// A too big packet is accepted if the receive queue is empty. It 24// does not trigger an immediate ACK. 25 +0 < P. 1:20001(20000) ack 1 win 257 26 +0 %{ assert tcpi_bytes_received == 20000, tcpi_bytes_received; }% 27 28// Send a RST immediately so that there is no rcv_wup/rcv_mwnd_seq update yet 29 +0 < R. 20001:20001(0) ack 1 win 257 30 31// Verify that the RST was accepted. Indirectly this also verifies that no 32// immediate ACK was sent for the data packet above. 33 +0 < . 20001:20001(0) ack 1 win 257 34 +0 > R 1:1(0) 35