| // SPDX-License-Identifier: GPL-2.0 |
| |
| --mss=1000 |
| |
| `./defaults.sh |
| sysctl -q net.ipv4.tcp_shrink_window=1 |
| 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 15 |
| |
| +0 < P. 10001:11024(1023) ack 1 win 257 |
| * > . 1:1(0) ack 11024 win 13 |
| |
| // Max window seq advertised 10001 + 15*1024 = 25361, last advertised: 11024 + 13*1024 = 24336 |
| |
| // Segment beyond the max window is dropped |
| +0 < P. 11024:25362(14338) ack 1 win 257 |
| * > . 1:1(0) ack 11024 win 13 |
| |
| // Segment using the max window is accepted |
| +0 < P. 11024:25361(14337) ack 1 win 257 |
| * > . 1:1(0) ack 25361 win 0 |
| |
| // Check LINUX_MIB_BEYOND_WINDOW has been incremented once |
| +0 `nstat | grep TcpExtBeyondWindow | grep -q " 1 "` |
