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tcp: add tcp_can_forward_retransmit 

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2008-09-20 21:21:54 -07:00 committed by David S. Miller
parent 184d68b2b0
commit b5afe7bc71
1 changed files with 28 additions and 18 deletions
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46
net/ipv4/tcp_output.c
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@ -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 */