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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2007-04-30 00:42:20 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-30 00:58:16 -0700
commitd551e4541dd60ae53459f77a971f2d6043431f5f (patch)
treecb328b1ec7ae32ad054c9d08de0274e4056a868f /net/ipv4/tcp_output.c
parent575ee7140dabe9b9c4f66f4f867039b97e548867 (diff)
downloadop-kernel-dev-d551e4541dd60ae53459f77a971f2d6043431f5f.zip
op-kernel-dev-d551e4541dd60ae53459f77a971f2d6043431f5f.tar.gz
[TCP] FRTO: RFC4138 allows Nagle override when new data must be sent
This is a corner case where less than MSS sized new data thingie is awaiting in the send queue. For F-RTO to work correctly, a new data segment must be sent at certain point or F-RTO cannot be used at all. RFC4138 allows overriding of Nagle at that point. Implementation uses frto_counter states 2 and 3 to distinguish when Nagle override is needed. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
-rw-r--r--net/ipv4/tcp_output.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index b5fa3c1..0faacf9 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1035,8 +1035,10 @@ static inline int tcp_nagle_test(struct tcp_sock *tp, struct sk_buff *skb,
if (nonagle & TCP_NAGLE_PUSH)
return 1;
- /* Don't use the nagle rule for urgent data (or for the final FIN). */
- if (tp->urg_mode ||
+ /* Don't use the nagle rule for urgent data (or for the final FIN).
+ * Nagle can be ignored during F-RTO too (see RFC4138).
+ */
+ if (tp->urg_mode || (tp->frto_counter == 2) ||
(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN))
return 1;
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