| // SPDX-License-Identifier: GPL-2.0 |
| // |
| // RFC 9293 Section 3.10.7.4: in SYN-RECEIVED, an exact RST resets |
| // the connection. A non-exact in-window RST elicits a challenge ACK, |
| // while an out-of-window RST is silently discarded. |
| |
| `./defaults.sh` |
| |
| // An exact RST removes the request socket. |
| 0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, 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 1000 <mss 1000,sackOK,nop,nop,nop,wscale 0> |
| +0 > S. 0:0(0) ack 1 <...> |
| +0 < R 1:1(0) win 1000 |
| +.1 < . 1:1(0) ack 1 win 1000 |
| +0 > R 1:1(0) |
| +0 close(3) = 0 |
| |
| // A non-exact in-window RST gets a challenge ACK and the request survives. |
| +0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, 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 1000 <mss 1000,sackOK,nop,nop,nop,wscale 0> |
| +0 > S. 0:0(0) ack 1 <...> |
| +0 < R 2:2(0) win 1000 |
| +0 > . 1:1(0) ack 1 |
| +0 < . 1:1(0) ack 1 win 1000 |
| +0 accept(3, ..., ...) = 4 |
| +0 close(4) = 0 |
| +0 close(3) = 0 |
| |
| // RST sequence validation precedes ACK validation. Even an RST|ACK |
| // with an unacceptable ACK value gets a challenge ACK. |
| +0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, 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 1000 <mss 1000,sackOK,nop,nop,nop,wscale 0> |
| +0 > S. 0:0(0) ack 1 <...> |
| +0 < R. 2:2(0) ack 100 win 1000 |
| +0 > . 1:1(0) ack 1 |
| +0 < . 1:1(0) ack 1 win 1000 |
| +0 accept(3, ..., ...) = 4 |
| +0 close(4) = 0 |
| +0 close(3) = 0 |
| |
| // An out-of-window RST is silent and does not remove the request. |
| +0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, 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 1000 <mss 1000,sackOK,nop,nop,nop,wscale 0> |
| +0 > S. 0:0(0) ack 1 <...> |
| +0 < R 100001:100001(0) win 1000 |
| +.1 < . 1:1(0) ack 1 win 1000 |
| +0 accept(3, ..., ...) = 4 |
| +0 close(4) = 0 |
| +0 close(3) = 0 |
