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authorJerry Chu <hkchu@google.com>2011-06-08 11:08:38 +0000
committerDavid S. Miller <davem@davemloft.net>2011-06-08 17:05:30 -0700
commit9ad7c049f0f79c418e293b1b68cf10d68f54fcdb (patch)
tree4b930b213f7a050afe9fae78432c1a4a6dce08a5 /net/ipv4/syncookies.c
parentaee80b54b235d34d87b25dfbe32f0f0ffee1b544 (diff)
tcp: RFC2988bis + taking RTT sample from 3WHS for the passive open side
This patch lowers the default initRTO from 3secs to 1sec per RFC2988bis. It falls back to 3secs if the SYN or SYN-ACK packet has been retransmitted, AND the TCP timestamp option is not on. It also adds support to take RTT sample during 3WHS on the passive open side, just like its active open counterpart, and uses it, if valid, to seed the initRTO for the data transmission phase. The patch also resets ssthresh to its initial default at the beginning of the data transmission phase, and reduces cwnd to 1 if there has been MORE THAN ONE retransmission during 3WHS per RFC5681. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/syncookies.c')
-rw-r--r--net/ipv4/syncookies.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 26461492a84..92bb9434b33 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -316,6 +316,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
ireq->wscale_ok = tcp_opt.wscale_ok;
ireq->tstamp_ok = tcp_opt.saw_tstamp;
req->ts_recent = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
+ treq->snt_synack = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsecr : 0;
/* We throwed the options of the initial SYN away, so we hope
* the ACK carries the same options again (see RFC1122 4.2.3.8)