Commit e880f8b3 authored by Manoj Basapathi's avatar Manoj Basapathi Committed by David S. Miller
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tcp: Reset tcp connections in SYN-SENT state 



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: default avatarManoj Basapathi <manojbm@codeaurora.org>
Signed-off-by: default avatarSauvik Saha <ssaha@codeaurora.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cc0626c2

net/ipv4/tcp.c

+2 −3
Original line number Diff line number Diff line
@@ -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);