On Fri, Jan 31, 2020 at 4:25 AM <sjpark@xxxxxxxxxx> wrote:
> Signed-off-by: SeongJae Park <sjpark@xxxxxxxxx>
> ---
> net/ipv4/tcp_input.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 2a976f57f7e7..b168e29e1ad1 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -5893,8 +5893,12 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
> * the segment and return)"
> */
> if (!after(TCP_SKB_CB(skb)->ack_seq, tp->snd_una) ||
> - after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt))
> + after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) {
> + /* Previous FIN/ACK or RST/ACK might be ignore. */
> + inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
> + TCP_ATO_MIN, TCP_RTO_MAX);
This is not what I suggested.
I suggested implementing a strategy where only the _first_ retransmit
would be done earlier.
So you need to look at the current counter of retransmit attempts,
then reset the timer if this SYN_SENT
socket never resent a SYN.
We do not want to trigger packet storms, if for some reason the remote
peer constantly sends
us the same packet.
Thanks.
> goto reset_and_undo;
> + }
>
> if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
> !between(tp->rx_opt.rcv_tsecr, tp->retrans_stamp,
> --
> 2.17.1
>
