Re: [PATCH net] tcp: Fix error ts_recent time during three-way handshake

[Eric Dumazet]

On Wed, Feb 19, 2025 at 4:08 AM Wang Hai <wanghai38@xxxxxxxxxx> wrote:
>

> Hi Eric,
>
> According to the plan, can we fix it like this?
>
> diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
> index b089b08e9617..1210d4967b94 100644
> --- a/net/ipv4/tcp_minisocks.c
> +++ b/net/ipv4/tcp_minisocks.c
> @@ -814,13 +814,6 @@ struct sock *tcp_check_req(struct sock *sk, struct
> sk_buff *skb,
>          }
>
>          /* In sequence, PAWS is OK. */
> -
> -       /* TODO: We probably should defer ts_recent change once
> -        * we take ownership of @req.
> -        */
> -       if (tmp_opt.saw_tstamp && !after(TCP_SKB_CB(skb)->seq,
> tcp_rsk(req)->rcv_nxt))
> -               WRITE_ONCE(req->ts_recent, tmp_opt.rcv_tsval);
> -
>          if (TCP_SKB_CB(skb)->seq == tcp_rsk(req)->rcv_isn) {
>                  /* Truncate SYN, it is out of window starting
>                     at tcp_rsk(req)->rcv_isn + 1. */
> @@ -878,6 +871,9 @@ struct sock *tcp_check_req(struct sock *sk, struct
> sk_buff *skb,
>          sock_rps_save_rxhash(child, skb);
>          tcp_synack_rtt_meas(child, req);
>          *req_stolen = !own_req;
> +       if (own_req && tmp_opt.saw_tstamp && !after(TCP_SKB_CB(skb)-
> seq, tcp_rsk(req)->rcv_nxt))
> +               tcp_sk(child)->rx_opt.ts_recent = tmp_opt.rcv_tsval;
> +
>          return inet_csk_complete_hashdance(sk, child, req, own_req);

Yes, this was the plan ;)