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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2008-09-20 21:21:54 -0700
committerDavid S. Miller <davem@davemloft.net>2008-09-20 21:21:54 -0700
commitb5afe7bc71a1689376c9b547376d17568469f3b3 (patch)
tree30a790da358ea20c790e16f87a4dcddc83cdb316
parent184d68b2b0b836587f92887b14baea41033ffeef (diff)
tcp: add tcp_can_forward_retransmit
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/tcp_output.c46
1 files changed, 28 insertions, 18 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index cfae61b40c4..957c4e3d217 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -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 */