From: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
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 <gerrit@xxxxxxxxxxxxxx>
Signed-off-by: Ian McDonald <ian.mcdonald@xxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
net/dccp/ccids/ccid3.c | 21 ++++++++++++---------
1 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index dfe1aa7..567146f 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);
--
1.5.3.4
-
To unsubscribe from this list: send the line "unsubscribe dccp" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
