| // SPDX-License-Identifier: GPL-2.0 |
| // Test what happens when client does not provide MD5 on SYN, |
| // but then does on the ACK that completes the three-way handshake. |
| |
| `./defaults.sh` |
| |
| // 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,sackOK,nop,nop,nop,wscale 10> |
| +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8> |
| // Ooh, weird: client provides MD5 option on the ACK: |
| +.01 < . 1:1(0) ack 1 win 514 <md5 000102030405060708090a0b0c0d0e0f,nop,nop> |
| +.01 < . 1:1(0) ack 1 win 514 <md5 000102030405060708090a0b0c0d0e0f,nop,nop> |
| |
| // The TCP listener refcount should be 2, but on buggy kernels it can be 0: |
| +0 `grep " 0A " /proc/net/tcp /proc/net/tcp6 | grep ":1F90"` |
| |
| // Now here comes the legit ACK: |
| +.01 < . 1:1(0) ack 1 win 514 |
| |
| // Make sure the connection is OK: |
| +0 accept(3, ..., ...) = 4 |
| |
| +.01 write(4, ..., 1000) = 1000 |
