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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/ipv6
parentaee80b54b235d34d87b25dfbe32f0f0ffee1b544 (diff)
downloadop-kernel-dev-9ad7c049f0f79c418e293b1b68cf10d68f54fcdb.zip
op-kernel-dev-9ad7c049f0f79c418e293b1b68cf10d68f54fcdb.tar.gz
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/ipv6')
-rw-r--r--net/ipv6/syncookies.c1
-rw-r--r--net/ipv6/tcp_ipv6.c5
2 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 8b9644a..89d5bf8 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -223,6 +223,7 @@ struct sock *cookie_v6_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;
treq->rcv_isn = ntohl(th->seq) - 1;
treq->snt_isn = cookie;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index d1fd287..a1ef61a 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1341,6 +1341,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
}
have_isn:
tcp_rsk(req)->snt_isn = isn;
+ tcp_rsk(req)->snt_synack = tcp_time_stamp;
security_inet_conn_request(sk, skb, req);
@@ -1509,6 +1510,10 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
tcp_sync_mss(newsk, dst_mtu(dst));
newtp->advmss = dst_metric_advmss(dst);
tcp_initialize_rcv_mss(newsk);
+ if (tcp_rsk(req)->snt_synack)
+ tcp_valid_rtt_meas(newsk,
+ tcp_time_stamp - tcp_rsk(req)->snt_synack);
+ newtp->total_retrans = req->retrans;
newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
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