From 6c08b2cf4843788e66a5e69b5512538e686ae3e3 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Tue, 20 Nov 2007 17:33:17 -0200 Subject: [PATCH] [CCID3]: Revert use of MSS instead of s This updates the CCID3 code with regard to two instances of using `MSS' in place of `s': 1. The RFC3390-based initial rate: both rfc3448bis as well as the Faster Restart draft now consistently use `s' instead of MSS. 2. Now agrees with section 4.2 of rfc3448bis: "If the sender is ready to send data when it does not yet have a round trip sample, the value of X is set to s bytes per second, for segment size s [...]" Signed-off-by: Gerrit Renker Signed-off-by: Ian McDonald Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- net/dccp/ccids/ccid3.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index f56aaecb56b3..5bf110b28abc 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -83,18 +83,21 @@ static void ccid3_hc_tx_set_state(struct sock *sk, } /* - * Compute the initial sending rate X_init according to RFC 3390: - * w_init = min(4 * MSS, max(2 * MSS, 4380 bytes)) - * X_init = w_init / RTT + * Compute the initial sending rate X_init in the manner of RFC 3390: + * + * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT + * + * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis + * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. * For consistency with other parts of the code, X_init is scaled by 2^6. */ static inline u64 rfc3390_initial_rate(struct sock *sk) { - const struct dccp_sock *dp = dccp_sk(sk); - const __u32 w_init = min(4 * dp->dccps_mss_cache, - max(2 * dp->dccps_mss_cache, 4380U)); + const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); + const __u32 w_init = min_t(__u32, 4 * hctx->ccid3hctx_s, + max_t(__u32, 2 * hctx->ccid3hctx_s, 4380)); - return scaled_div(w_init << 6, ccid3_hc_tx_sk(sk)->ccid3hctx_rtt); + return scaled_div(w_init << 6, hctx->ccid3hctx_rtt); } /* @@ -336,8 +339,8 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) hctx->ccid3hctx_x = rfc3390_initial_rate(sk); hctx->ccid3hctx_t_ld = now; } else { - /* Sender does not have RTT sample: X = MSS/second */ - hctx->ccid3hctx_x = dp->dccps_mss_cache; + /* Sender does not have RTT sample: X_pps = 1 pkt/sec */ + hctx->ccid3hctx_x = hctx->ccid3hctx_s; hctx->ccid3hctx_x <<= 6; } ccid3_update_send_interval(hctx); -- 2.30.2