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Commit b5afe7bc authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

tcp: add tcp_can_forward_retransmit 



Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 184d68b2

net/ipv4/tcp_output.c

+28 −18
Original line number Diff line number Diff line
@@ -1992,6 +1992,33 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb) 
	return err;

}



static int tcp_can_forward_retransmit(struct sock *sk)

{

	const struct inet_connection_sock *icsk = inet_csk(sk);

	struct tcp_sock *tp = tcp_sk(sk);



	/* Forward retransmissions are possible only during Recovery. */

	if (icsk->icsk_ca_state != TCP_CA_Recovery)

		return 0;



	/* No forward retransmissions in Reno are possible. */

	if (tcp_is_reno(tp))

		return 0;



	/* Yeah, we have to make difficult choice between forward transmission

	 * and retransmission... Both ways have their merits...

	 *

	 * For now we do not retransmit anything, while we have some new

	 * segments to send. In the other cases, follow rule 3 for

	 * NextSeg() specified in RFC3517.

	 */



	if (tcp_may_send_now(sk))

		return 0;



	return 1;

}



/* This gets called after a retransmit timeout, and the initially

 * retransmitted data is acknowledged.  It tries to continue

 * resending the rest of the retransmit queue, until either
@@ -2057,24 +2084,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 
	}



	/* OK, demanded retransmission is finished. */



	/* Forward retransmissions are possible only during Recovery. */

	if (icsk->icsk_ca_state != TCP_CA_Recovery)

		return;



	/* No forward retransmissions in Reno are possible. */

	if (tcp_is_reno(tp))

		return;



	/* Yeah, we have to make difficult choice between forward transmission

	 * and retransmission... Both ways have their merits...

	 *

	 * For now we do not retransmit anything, while we have some new

	 * segments to send. In the other cases, follow rule 3 for

	 * NextSeg() specified in RFC3517.

	 */



	if (tcp_may_send_now(sk))

	if (!tcp_can_forward_retransmit(sk))

		return;



	/* If nothing is SACKed, highest_sack in the loop won't be valid */