Commit 56763311 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'tcp-tcp_tx_timestamp-fix' 

Eric Dumazet says:

====================
tcp: tcp_tx_timestamp() fix

Fix an old bug in tcp_tx_timestamp().

Add one corresponding packetdrill test.
====================

Link: https://patch.msgid.link/20260127123828.4098577-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 5b71de34 6080d525

net/ipv4/tcp.c

+3 −0
Original line number Diff line number Diff line
@@ -501,6 +501,9 @@ static void tcp_tx_timestamp(struct sock *sk, struct sockcm_cookie *sockc) 
	struct sk_buff *skb = tcp_write_queue_tail(sk);

	u32 tsflags = sockc->tsflags;



	if (unlikely(!skb))

		skb = skb_rb_last(&sk->tcp_rtx_queue);



	if (tsflags && skb) {

		struct skb_shared_info *shinfo = skb_shinfo(skb);

		struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);

tools/testing/selftests/net/packetdrill/tcp_timestamping_tcp_tx_timestamp_bug.pkt

0 → 100644
+70 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Test after "tcp: tcp_tx_timestamp() must look at the rtx queue"



// This test is about receiving the SCM_TSTAMP_ACK,

// we do not care about its SCM_TIMESTAMPING precision.

--tolerance_usecs=1000000



`./defaults.sh

sysctl -q net.ipv4.tcp_min_tso_segs=70

`



// Create a socket and set it to non-blocking.

    0	socket(..., SOCK_STREAM, IPPROTO_TCP) = 3

   +0	fcntl(3, F_GETFL) = 0x2 (flags O_RDWR)

   +0	fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0



// Establish connection and verify that there was no error.

   +0	connect(3, ..., ...) = -1 EINPROGRESS (Operation now in progress)

   +0	> S 0:0(0) <mss 1460,sackOK,TS val 100 ecr 0,nop,wscale 8>

+.010	< S. 0:0(0) ack 1 win 65535 <mss 1000,sackOK,TS val 700 ecr 100,nop,wscale 7>

   +0	> . 1:1(0) ack 1 <nop,nop,TS val 200 ecr 700>

   +0	getsockopt(3, SOL_SOCKET, SO_ERROR, [0], [4]) = 0

   +0	setsockopt(3, SOL_SOCKET, SO_SNDBUF, [30000], 4) = 0



   +0   write(3, ..., 9880) = 9880

   +0   > P. 1:9881(9880) ack 1 <nop,nop,TS val 200 ecr 700>

+.010   < . 1:1(0) ack 9881 win 10000 <nop,nop,TS val 701 ecr 200>



   +0   write(3, ..., 19760) = 19760

   +0   > P. 9881:29641(19760) ack 1 <nop,nop,TS val 201 ecr 701>

+.010   < . 1:1(0) ack 29641 win 10000 <nop,nop,TS val 702 ecr 201>



   +0   write(3, ..., 39520) = 39520

   +0   > P. 29641:69161(39520) ack 1 <nop,nop,TS val 202 ecr 702>

+.010   < . 1:1(0) ack 69161 win 10000 <nop,nop,TS val 703 ecr 202>



// One more write to increase cwnd

   +0	write(3, ..., 79040) = 79040

   +0	> P. 69161:108681(39520) ack 1 <nop,nop,TS val 203 ecr 703>

   +0	> P. 108681:148201(39520) ack 1 <nop,nop,TS val 203 ecr 703>

+.010	< . 1:1(0) ack 148201 win 1000 <nop,nop,TS val 704 ecr 203>



   +0	setsockopt(3, SOL_SOCKET, SO_TIMESTAMPING,

		   [SOF_TIMESTAMPING_TX_ACK | SOF_TIMESTAMPING_SOFTWARE |

		    SOF_TIMESTAMPING_OPT_ID], 4) = 0



// We have one write filling one skb

// last byte can not be stored because of our small SO_SNDBUF

   +0	write(3, ..., 65209) = 65208

   +0	> P. 148201:213409(65208) ack 1 <nop,nop,TS val 204 ecr 704>

+.010	< . 1:1(0) ack 213409 win 1000 <nop,nop,TS val 705 ecr 204>



// SCM_TSTAMP_ACK should be received after the last ack at

// t=60ms.

   +0	recvmsg(3, {msg_name(...)=...,

		    msg_iov(1)=[{...,0}],

                    msg_flags=MSG_ERRQUEUE|MSG_TRUNC,

                    msg_control=[

			{cmsg_level=SOL_SOCKET,

			 cmsg_type=SCM_TIMESTAMPING,

			 cmsg_data={scm_sec=0,scm_nsec=60000000}},

			{cmsg_level=CMSG_LEVEL_IP,

			 cmsg_type=CMSG_TYPE_RECVERR,

			 cmsg_data={ee_errno=ENOMSG,

				    ee_origin=SO_EE_ORIGIN_TIMESTAMPING,

				    ee_type=0,

				    ee_code=0,

				    ee_info=SCM_TSTAMP_ACK,

				    ee_data=65207}}

		    ]}, MSG_ERRQUEUE) = 0