On 4/5/21 7:02 PM, Manoj Basapathi wrote:
> Userspace sends tcp connection (sock) destroy on network switch
> i.e switching the default network of the device between multiple
> networks(Cellular/Wifi/Ethernet).
>
> Kernel though doesn't send reset for the connections in SYN-SENT state
> and these connections continue to remain.
> Even as per RFC 793, there is no hard rule to not send RST on ABORT in
> this state.
>
> Modify tcp_abort and tcp_disconnect behavior to send RST for connections
> in syn-sent state to avoid lingering connections on network switch.
>
> Signed-off-by: Manoj Basapathi <mano...@codeaurora.org>
> Signed-off-by: Sauvik Saha <ss...@codeaurora.org>
> ---
> net/ipv4/tcp.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index e14fd0c50c10..627a472161fb 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -2888,7 +2888,7 @@ static inline bool tcp_need_reset(int state)
> {
> return (1 << state) &
> (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
> - TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
> + TCPF_FIN_WAIT2 | TCPF_SYN_RECV | TCPF_SYN_SENT);
> }
>
> static void tcp_rtx_queue_purge(struct sock *sk)
> @@ -2954,8 +2954,7 @@ int tcp_disconnect(struct sock *sk, int flags)
> */
> tcp_send_active_reset(sk, gfp_any());
> sk->sk_err = ECONNRESET;
> - } else if (old_state == TCP_SYN_SENT)
> - sk->sk_err = ECONNRESET;
> + }
>
> tcp_clear_xmit_timers(sk);
> __skb_queue_purge(&sk->sk_receive_queue);
>
This is a completely buggy patch.
This has been sent to many people but _not_ to TCP maintainers ????
I will send a revert.
