From 34a081be8e14b7ada70e069b65b05d54db4af497 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Thu, 4 Sep 2008 07:30:19 +0200 Subject: dccp tfrc: Let dccp_tfrc_lib do the sampling work This migrates more TFRC-related code into the dccp_tfrc_lib: * sampling of the packet size `s' (which is only needed until the first loss interval is computed (ccid3_first_li)); * updating the byte-counter `bytes_recvd' in between sending feedbacks. The result is a better separation of CCID-3 specific and TFRC specific code, which aids future integration with ECN and e.g. CCID-4. Further changes: ---------------- * replaced magic number of 536 with equivalent constant TCP_MIN_RCVMSS; (this constant is also used when no estimate for `s' is available). Signed-off-by: Gerrit Renker --- net/dccp/ccids/lib/packet_history.c | 10 ++++++++++ net/dccp/ccids/lib/packet_history.h | 16 ++++++++++++++++ 2 files changed, 26 insertions(+) (limited to 'net/dccp/ccids/lib') diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c index 8ea96903033..ee34b456424 100644 --- a/net/dccp/ccids/lib/packet_history.c +++ b/net/dccp/ccids/lib/packet_history.c @@ -352,6 +352,16 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, __three_after_loss(h); } + /* + * Update moving-average of `s' and the sum of received payload bytes. + */ + if (dccp_data_packet(skb)) { + const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; + + h->packet_size = tfrc_ewma(h->packet_size, payload, 9); + h->bytes_recvd += payload; + } + /* RFC 3448, 6.1: update I_0, whose growth implies p <= p_prev */ if (!is_new_loss) tfrc_lh_update_i_mean(lh, skb); diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h index e9d8097947d..b7c87a1a272 100644 --- a/net/dccp/ccids/lib/packet_history.h +++ b/net/dccp/ccids/lib/packet_history.h @@ -91,12 +91,16 @@ 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 + * @packet_size: Packet size in bytes (as per RFC 3448, 3.1) + * @bytes_recvd: Number of bytes received since last sending feedback */ struct tfrc_rx_hist { struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1]; u8 loss_count:2, loss_start:2; #define rtt_sample_prev loss_start + u32 packet_size, + bytes_recvd; }; /** @@ -140,6 +144,18 @@ static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h) return h->loss_count > 0; } +/* + * Accessor functions to retrieve parameters sampled by the RX history + */ +static inline u32 tfrc_rx_hist_packet_size(const struct tfrc_rx_hist *h) +{ + if (h->packet_size == 0) { + DCCP_WARN("No sample for s, using fallback\n"); + return TCP_MIN_RCVMSS; + } + return h->packet_size; +} + extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, const struct sk_buff *skb, const u64 ndp); -- cgit v1.2.3