From cdbab6236605dc11780779d9af689aea7d58cab1 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 31 Oct 2023 06:19:45 +0000 Subject: tcp: fix fastopen code vs usec TS After blamed commit, TFO client-ack-dropped-then-recovery-ms-timestamps packetdrill test failed. David Morley and Neal Cardwell started investigating and Neal pointed that we had : tcp_conn_request() tcp_try_fastopen() -> tcp_fastopen_create_child -> child = inet_csk(sk)->icsk_af_ops->syn_recv_sock() -> tcp_create_openreq_child() -> copy req_usec_ts from req: newtp->tcp_usec_ts = treq->req_usec_ts; // now the new TFO server socket always does usec TS, no matter // what the route options are... send_synack() -> tcp_make_synack() // disable tcp_rsk(req)->req_usec_ts if route option is not present: if (tcp_rsk(req)->req_usec_ts < 0) tcp_rsk(req)->req_usec_ts = dst_tcp_usec_ts(dst); tcp_conn_request() has the initial dst, we can initialize tcp_rsk(req)->req_usec_ts there instead of later in send_synack(); This means tcp_rsk(req)->req_usec_ts can be a boolean. Many thanks to David an Neal for their help. Fixes: 614e8316aa4c ("tcp: add support for usec resolution in TCP TS values") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202310302216.f79d78bc-oliver.sang@intel.com Suggested-by: Neal Cardwell Signed-off-by: Eric Dumazet Cc: David Morley Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 50aaa1527150..bcb55d98004c 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -7115,7 +7115,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, req->syncookie = want_cookie; tcp_rsk(req)->af_specific = af_ops; tcp_rsk(req)->ts_off = 0; - tcp_rsk(req)->req_usec_ts = -1; + tcp_rsk(req)->req_usec_ts = false; #if IS_ENABLED(CONFIG_MPTCP) tcp_rsk(req)->is_mptcp = 0; #endif @@ -7143,9 +7143,10 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, if (!dst) goto drop_and_free; - if (tmp_opt.tstamp_ok) + if (tmp_opt.tstamp_ok) { + tcp_rsk(req)->req_usec_ts = dst_tcp_usec_ts(dst); tcp_rsk(req)->ts_off = af_ops->init_ts_off(net, skb); - + } if (!want_cookie && !isn) { int max_syn_backlog = READ_ONCE(net->ipv4.sysctl_max_syn_backlog); -- cgit