// SPDX-License-Identifier: GPL-2.0 // // Minimal passive open. // Peer is first to close. `./defaults.sh` // Open listener socket 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 // Incoming connection: passive open: three-way handshake +0 < S 0:0(0) win 65535 +0 > S. 0:0(0) ack 1 +0 < . 1:1(0) ack 1 win 257 // Open connection socket and close listener socket +0 accept(3, ..., ...) = 4 +0 close(3) = 0 // Peer sends data: acknowledge and receive +0 < P. 1:1001(1000) ack 1 win 257 +0 > . 1:1(0) ack 1001 +0 recv(4, ..., 1000, 0) = 1000 // Peer initiates connection close +0 < F. 1001:1001(0) ack 1 win 257 +.04 > . 1:1(0) ack 1002 // Local socket also closes its side +0 close(4) = 0 +0 > F. 1:1(0) ack 1002 +0 < . 1002:1002(0) ack 2 win 257