Calculate t_nom as per RFC3448 section 4.6. We have been making it too
complicated previously.
We do have a bit of a hack for initial ipi as we are not picking up the rtt
from initial setup. This should be tidied up in future.
Signed-off-by: Ian McDonald <[EMAIL PROTECTED]>
---
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 1ebb4da..57f9fb8 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -82,12 +82,10 @@ static void ccid3_hc_tx_set_state(struct sock *sk,
/*
* Recalculate scheduled nominal send time t_nom, inter-packet interval
- * t_ipi, and delta value. Should be called after each change to X.
+ * t_ipi, and delta value. Should be called after each packet sent.
*/
-static inline void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx)
+static void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx)
{
- timeval_sub_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
-
/* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
hctx->ccid3hctx_t_ipi = scaled_div(hctx->ccid3hctx_s,
hctx->ccid3hctx_x >> 6);
@@ -118,8 +116,6 @@ static inline void ccid3_update_send_time(struct
ccid3_hc_tx_sock *hctx)
* fine-grained resolution of sending rates. This requires scaling by 2^6
* throughout the code. Only X_calc is unscaled (in bytes/second).
*
- * If X has changed, we also update the scheduled send time t_now,
- * the inter-packet interval t_ipi, and the delta value.
*/
static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
@@ -145,13 +141,10 @@ static void ccid3_hc_tx_update_x(struct sock *sk, struct
timeval *now)
hctx->ccid3hctx_t_ld = *now;
}
- if (hctx->ccid3hctx_x != old_x) {
+ if (hctx->ccid3hctx_x != old_x)
ccid3_pr_debug("X_prev=%llu, X_now=%llu, X_calc=%u, "
"X_recv=%llu\n", old_x >> 6, hctx->ccid3hctx_x
>> 6,
hctx->ccid3hctx_x_calc, hctx->ccid3hctx_x_recv
>> 6);
-
- ccid3_update_send_time(hctx);
- }
}
/*
@@ -344,6 +337,8 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct
sk_buff *skb)
/* Set t_0 for initial packet */
hctx->ccid3hctx_t_nom = now;
+ timeval_add_usecs(&hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi);
break;
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
@@ -361,6 +356,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct
sk_buff *skb)
return delay / 1000L;
ccid3_hc_tx_update_win_count(hctx, &now);
+ ccid3_update_send_time(hctx);
break;
case TFRC_SSTATE_TERM:
DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
@@ -371,9 +367,6 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct
sk_buff *skb)
dp->dccps_hc_tx_insert_options = 1;
DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
- /* set the nominal send time for the next following packet */
- timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
-
return 0;
}
@@ -486,6 +479,11 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk,
struct sk_buff *skb)
hctx->ccid3hctx_x = scaled_div(w_init << 6,
r_sample);
hctx->ccid3hctx_t_ld = now;
+
+ /* adjust down from initial 1 second now we have rtt */
+ timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi);
+
ccid3_update_send_time(hctx);
ccid3_pr_debug("%s(%p), s=%u, MSS=%u, w_init=%u, "
-
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