From 4886fcad6e12572afbd230dfab1b268eace20d6d Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Sun, 29 Aug 2010 19:23:13 +0000 Subject: 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 Signed-off-by: David S. Miller --- net/dccp/ccids/ccid2.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/dccp/ccids/ccid2.c') diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c index b9c942a09c98..dc18172b1e59 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); } } -- cgit v1.2.2