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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2010-08-29 19:23:13 +0000
committerDavid S. Miller <davem@davemloft.net>2010-08-30 13:45:27 -0700
commit4886fcad6e12572afbd230dfab1b268eace20d6d (patch)
treec0ac7dc930a8de315083ec3882ff78a325747e70 /net/dccp
parent22b71c8f4f3db8df92f5e7b081c265bc56c0bd2f (diff)
downloadvexpress-lsk-4886fcad6e12572afbd230dfab1b268eace20d6d.tar.gz
dccp ccid-2: Share TCP's minimum RTO code
Using a fixed RTO_MIN of 0.2 seconds was found to cause problems for CCID-2 over 802.11g: at least once per session there was a spurious timeout. It helped to then increase the the value of RTO_MIN over this link. Since the problem is the same as in TCP, this patch makes the solution from commit "05bb1fad1cde025a864a90cfeb98dcbefe78a44a" "[TCP]: Allow minimum RTO to be configurable via routing metrics." available to DCCP. This avoids reinventing the wheel, so that e.g. the following works in the expected way now also for CCID-2: > ip route change 10.0.0.2 rto_min 800 dev ath0 Luckily this useful rto_min function was recently moved to net/tcp.h, which simplifies sharing code originating from TCP. Documentation also updated (plus minor whitespace fixes). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp')
-rw-r--r--net/dccp/ccids/ccid2.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index b9c942a09c9..dc18172b1e5 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -325,8 +325,9 @@ static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
hc->tx_srtt = m << 3;
hc->tx_mdev = m << 1;
- hc->tx_mdev_max = max(TCP_RTO_MIN, hc->tx_mdev);
+ hc->tx_mdev_max = max(hc->tx_mdev, tcp_rto_min(sk));
hc->tx_rttvar = hc->tx_mdev_max;
+
hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
} else {
/* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */
@@ -367,7 +368,7 @@ static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
hc->tx_rttvar -= (hc->tx_rttvar -
hc->tx_mdev_max) >> 2;
hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
- hc->tx_mdev_max = TCP_RTO_MIN;
+ hc->tx_mdev_max = tcp_rto_min(sk);
}
}