Commit a8b1750e authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
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selftest: packetdrill: Import opt34/icmp-before-accept.pkt. 



This imports the non-experimental version of icmp-before-accept.pkt.

This file tests the scenario where an ICMP unreachable packet for a
not-yet-accept()ed socket changes its state to TCP_CLOSE, but the
SYN data must be read without error, and the following read() returns
EHOSTUNREACH.

Note that this test support only IPv4 as icmp is used.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250927213022.1850048-9-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5ed080f8

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_icmp-before-accept.pkt

0 → 100644
+49 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

//

// Send an ICMP host_unreachable pkt to a pending SYN_RECV req.

//

// If it's a TFO req, the ICMP error will cause it to switch

// to TCP_CLOSE state but remains in the acceptor queue.



--ip_version=ipv4



`./defaults.sh`



    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 setsockopt(3, SOL_TCP, TCP_FASTOPEN, [1], 4) = 0



   +0 < S 0:10(10) win 32792 <mss 1460,sackOK,nop,nop,FO TFO_COOKIE,nop,nop>

   +0 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK>



// Out-of-window icmp is ignored but accounted.

   +0 `nstat > /dev/null`

   +0 < icmp unreachable [5000:6000(1000)]

   +0 `nstat | grep TcpExtOutOfWindowIcmps > /dev/null`



// Valid ICMP unreach.

   +0 < icmp unreachable host_unreachable [0:10(10)]



// Unlike the non-TFO case, the req is still there to be accepted.

   +0 accept(3, ..., ...) = 4

   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) != 0, tcpi_options }%



// tcp_done_with_error() in tcp_v4_err() sets sk->sk_state

// to TCP_CLOSE

   +0 %{ assert tcpi_state == TCP_CLOSE, tcpi_state }%



// The 1st read will succeed and return the data in SYN

   +0 read(4, ..., 512) = 10



// The 2nd read will fail.

   +0 read(4, ..., 512) = -1 EHOSTUNREACH (No route to host)



// But is no longer writable because it's in TCP_CLOSE state.

   +0 write(4, ..., 100) = -1 EPIPE (Broken Pipe)



// inbound pkt will trigger RST because the socket has been moved

// off the TCP hash tables.

   +0 < . 1:1(0) ack 1 win 32792

   +0 > R 1:1(0)