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dccp tfrc: Let dccp_tfrc_lib do the sampling work

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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 <gerrit@erg.abdn.ac.uk>
This commit is contained in:
Gerrit Renker
2008-09-04 07:30:19 +02:00
부모 3ca7aea041
커밋 34a081be8e
5개의 변경된 파일과 35개의 추가작업 그리고 35개의 파일을 삭제
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38
net/dccp/ccids/ccid3.c
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@@ -590,12 +590,9 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
* would bring X down to s/t_mbi. That is why we return
* X_recv according to rfc3448bis-06 for the moment.
*/
u32 rtt = hcrx->rtt ? : DCCP_FALLBACK_RTT, s = hcrx->s;
u32 rtt = hcrx->rtt ? : DCCP_FALLBACK_RTT,
s = tfrc_rx_hist_packet_size(&hcrx->hist);
if (s == 0) {
DCCP_WARN("No sample for s, using fallback\n");
s = TCP_MIN_RCVMSS;
}
hcrx->x_recv = scaled_div32(s, 2 * rtt);
break;
}
@@ -617,7 +614,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
if (delta <= 0)
DCCP_BUG("delta (%ld) <= 0", (long)delta);
else
hcrx->x_recv = scaled_div32(hcrx->bytes_recv, delta);
hcrx->x_recv = scaled_div32(hcrx->hist.bytes_recvd, delta);
break;
default:
return;
@@ -628,7 +625,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
hcrx->tstamp_last_feedback = now;
hcrx->last_counter = dccp_hdr(skb)->dccph_ccval;
hcrx->bytes_recv = 0;
hcrx->hist.bytes_recvd = 0;
dp->dccps_hc_rx_insert_options = 1;
dccp_send_ack(sk);
@@ -669,7 +666,8 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
static u32 ccid3_first_li(struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
u32 x_recv, p, delta;
u32 x_recv, p, delta,
s = tfrc_rx_hist_packet_size(&hcrx->hist);
u64 fval;
/*
@@ -686,7 +684,7 @@ static u32 ccid3_first_li(struct sock *sk)
}
delta = ktime_to_us(net_timedelta(hcrx->tstamp_last_feedback));
x_recv = scaled_div32(hcrx->bytes_recv, delta);
x_recv = scaled_div32(hcrx->hist.bytes_recvd, delta);
if (x_recv == 0) { /* would also trigger divide-by-zero */
DCCP_WARN("X_recv==0\n");
if (hcrx->x_recv == 0) {
@@ -696,8 +694,7 @@ static u32 ccid3_first_li(struct sock *sk)
x_recv = hcrx->x_recv;
}
fval = scaled_div(hcrx->s, hcrx->rtt);
fval = scaled_div32(fval, x_recv);
fval = scaled_div32(scaled_div(s, hcrx->rtt), x_recv);
p = tfrc_calc_x_reverse_lookup(fval);
ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
@@ -724,31 +721,12 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) {
if (is_data_packet) {
const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
do_feedback = CCID3_FBACK_INITIAL;
ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
hcrx->s = payload;
/*
* Not necessary to update bytes_recv here,
* since X_recv = 0 for the first feedback packet (cf.
* RFC 3448, 6.3) -- gerrit
*/
}
goto update_records;
}
if (tfrc_rx_hist_duplicate(&hcrx->hist, skb))
return; /* done receiving */
if (is_data_packet) {
const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
/*
* Update moving-average of s and the sum of received payload bytes
*/
hcrx->s = tfrc_ewma(hcrx->s, payload, 9);
hcrx->bytes_recv += payload;
}
if (tfrc_rx_hist_loss_pending(&hcrx->hist))
return; /* done receiving */