diff options
| author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2008-09-04 07:30:19 +0200 |
|---|---|---|
| committer | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2008-09-04 07:45:41 +0200 |
| commit | 2b81143aa3505e2460b24b357996c2f21840ea58 (patch) | |
| tree | 37f752fb85c563f965655cec834bb289fd831137 /net/dccp/ccids/lib/packet_history.h | |
| parent | 2f3e3bbad917c426d3aba03a535809e5699de156 (diff) | |
dccp ccid-3: Always perform receiver RTT sampling
This updates the CCID-3 receiver in part with regard to errata 610 and 611
(http://www.rfc-editor.org/errata_list.php), which change RFC 4342 to use the
Receive Rate as specified in rfc3448bis, requiring to constantly sample the
RTT (or use a sender RTT).
Doing this requires reusing the RX history structure after dealing with a loss.
The patch does not resolve how to compute X_recv if the interval is less
than 1 RTT. A FIXME has been added (and is resolved in subsequent patch).
Furthermore, since this is all TFRC-based functionality, the RTT estimation
is now also performed by the dccp_tfrc_lib module. This further simplifies
the CCID-3 code.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'net/dccp/ccids/lib/packet_history.h')
| -rw-r--r-- | net/dccp/ccids/lib/packet_history.h | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h index b7c87a1a272..ba5832bbc34 100644 --- a/net/dccp/ccids/lib/packet_history.h +++ b/net/dccp/ccids/lib/packet_history.h @@ -91,6 +91,7 @@ struct tfrc_rx_hist_entry { * @loss_count: Number of entries in circular history * @loss_start: Movable index (for loss detection) * @rtt_sample_prev: Used during RTT sampling, points to candidate entry + * @rtt_estimate: Receiver RTT estimate * @packet_size: Packet size in bytes (as per RFC 3448, 3.1) * @bytes_recvd: Number of bytes received since last sending feedback */ @@ -98,7 +99,10 @@ struct tfrc_rx_hist { struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1]; u8 loss_count:2, loss_start:2; + /* Receiver RTT sampling */ #define rtt_sample_prev loss_start + u32 rtt_estimate; + /* Receiver sampling of application payload lengths */ u32 packet_size, bytes_recvd; }; @@ -154,6 +158,15 @@ static inline u32 tfrc_rx_hist_packet_size(const struct tfrc_rx_hist *h) return TCP_MIN_RCVMSS; } return h->packet_size; + +} +static inline u32 tfrc_rx_hist_rtt(const struct tfrc_rx_hist *h) +{ + if (h->rtt_estimate == 0) { + DCCP_WARN("No RTT estimate available, using fallback RTT\n"); + return DCCP_FALLBACK_RTT; + } + return h->rtt_estimate; } extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, @@ -167,8 +180,8 @@ extern int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, const u64 ndp, u32 (*first_li)(struct sock *sk), struct sock *sk); -extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, - const struct sk_buff *skb); +extern void tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, + const struct sk_buff *skb); extern int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk); extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h); |