1// SPDX-License-Identifier: GPL-2.0 2// 3// Send a RST to a TFO socket after it is accepted. 4// 5// The socket will change to TCP_CLOSE state with pending data so 6// write() will fail. Pending data can be still be read and close() 7// won't trigger RST if data is not read 8// 9// 565b7b2d2e63 ("tcp: do not send reset to already closed sockets") 10// https://lore.kernel.org/netdev/4C1A2502.1030502@openvz.org/ 11 12`./defaults.sh` 13 14 0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3 15 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 16 +0 bind(3, ..., ...) = 0 17 +0 listen(3, 1) = 0 18 +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN, [1], 4) = 0 19 20 +0 < S 0:10(10) win 32792 <mss 1460,sackOK,nop,nop, FO TFO_COOKIE,nop,nop> 21 +0 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK> 22 23 +0 accept(3, ..., ...) = 4 24 +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) != 0, tcpi_options }% 25 +0 %{ assert tcpi_state == TCP_SYN_RECV, tcpi_state }% 26 27// tcp_done() sets sk->sk_state to TCP_CLOSE and clears tp->fastopen_rsk 28 +0 < R. 11:11(0) win 32792 29 +0 %{ assert tcpi_state == TCP_CLOSE, tcpi_state }% 30 31 +0 write(4, ..., 100) = -1 ECONNRESET(Connection reset by peer) 32 +0 close(4) = 0 33