Commit c337578a authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: make tcp_rcv_synsent_state_process() drop monitor friend 



1) A valid RST packet should be consumed, to not confuse drop monitor.

2) Same remark for packet validating cross syn setup,
   even if we might ignore part of it.

3) When third packet of 3WHS is delayed, do not pretend
   the SYNACK was dropped.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e7c89ae4

net/ipv4/tcp_input.c

+8 −9
Original line number Diff line number Diff line
@@ -6186,7 +6186,9 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, 


		if (th->rst) {

			tcp_reset(sk, skb);

			goto discard;

consume:

			__kfree_skb(skb);

			return 0;

		}



		/* rfc793:
@@ -6275,13 +6277,9 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, 
			tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);

			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,

						  TCP_DELACK_MAX, TCP_RTO_MAX);



discard:

			tcp_drop(sk, skb);

			return 0;

		} else {

			tcp_send_ack(sk);

			goto consume;

		}

		tcp_send_ack(sk);

		return -1;

	}
@@ -6350,7 +6348,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, 
		 */

		return -1;

#else

		goto discard;

		goto consume;

#endif

	}

	/* "fifth, if neither of the SYN or RST bits is set then
@@ -6360,7 +6358,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, 
discard_and_undo:

	tcp_clear_options(&tp->rx_opt);

	tp->rx_opt.mss_clamp = saved_clamp;

	goto discard;

	tcp_drop(sk, skb);

	return 0;



reset_and_undo:

	tcp_clear_options(&tp->rx_opt);