diff options
| author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2010-06-22 01:14:35 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-06-25 21:33:15 -0700 |
| commit | 59b80802a8a18b64d38b51aa168253684b2649d5 (patch) | |
| tree | b6be92f705d00796733e03e43041605b74d0ce5f /net/dccp/options.c | |
| parent | a7d13fbf85375698879d16f118af77fbfcc2de44 (diff) | |
| download | lwn-59b80802a8a18b64d38b51aa168253684b2649d5.tar.gz lwn-59b80802a8a18b64d38b51aa168253684b2649d5.zip | |
dccp: make implementation of Syn-RTT symmetric
This patch is thanks to Andre Noll who reported the issue and helped testing.
The Syn-RTT sampled during the initial handshake currently only works for
the client sending the DCCP-Request. TFRC penalizes the absence of an RTT
sample with a very slow initial speed (1 packet per second), which delays
slow-start significantly, resulting in sluggish performance.
This patch mirrors the "Syn RTT" principle by adding a timestamp also onto
the DCCP-Response, producing an RTT sample when the (Data)Ack completing
the handshake arrives.
Also changed the documentation to 'TFRC' since Syn RTTs are also used by CCID-4.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/options.c')
| -rw-r--r-- | net/dccp/options.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/dccp/options.c b/net/dccp/options.c index 4973badb5d55..bfda087bd90d 100644 --- a/net/dccp/options.c +++ b/net/dccp/options.c @@ -529,7 +529,7 @@ int dccp_insert_options(struct sock *sk, struct sk_buff *skb) if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) { /* * Obtain RTT sample from Request/Response exchange. - * This is currently used in CCID 3 initialisation. + * This is currently used for TFRC initialisation. */ if (dccp_insert_option_timestamp(skb)) return -1; @@ -562,6 +562,10 @@ int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb) if (dccp_feat_insert_opts(NULL, dreq, skb)) return -1; + /* Obtain RTT sample from Response/Ack exchange (used by TFRC). */ + if (dccp_insert_option_timestamp(skb)) + return -1; + if (dreq->dreq_timestamp_echo != 0 && dccp_insert_option_timestamp_echo(NULL, dreq, skb)) return -1; |