[CCID3]: Accurately determine idle & application-limited periods
This fixes/updates the handling of idle and application-limited periods in CCID3,
which currently is broken: there is no detection as to how long a sender has been
idle - there is only one flag which is toggled in between function calls.
Being obsolete now, the `idle' flag is removed.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index c025236..94a3228 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -119,6 +119,13 @@
}
+static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now)
+{
+ u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
+
+ return delta / hctx->ccid3hctx_rtt;
+}
+
/**
* ccid3_hc_tx_update_x - Update allowed sending rate X
* @stamp: most recent time if available - can be left NULL.
@@ -139,10 +146,11 @@
/*
* Handle IDLE periods: do not reduce below RFC3390 initial sending rate
- * when idling [RFC 4342, 5.1]. See also draft-ietf-dccp-rfc3448bis.
+ * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis:
+ * a sender is idle if it has not sent anything over a 2-RTT-period.
* For consistency with X and X_recv, min_rate is also scaled by 2^6.
*/
- if (unlikely(hctx->ccid3hctx_idle)) {
+ if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) {
min_rate = rfc3390_initial_rate(sk);
min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
}
@@ -228,8 +236,6 @@
ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state));
- hctx->ccid3hctx_idle = 1;
-
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_FBACK:
/* RFC 3448, 4.4: Halve send rate directly */
@@ -372,7 +378,6 @@
/* prepare to send now (add options etc.) */
dp->dccps_hc_tx_insert_options = 1;
DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
- hctx->ccid3hctx_idle = 0;
/* set the nominal send time for the next following packet */
hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom,
@@ -531,9 +536,6 @@
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + usecs_to_jiffies(t_nfb));
-
- /* set idle flag */
- hctx->ccid3hctx_idle = 1;
break;
case TFRC_SSTATE_NO_SENT: /* fall through */
case TFRC_SSTATE_TERM: /* ignore feedback when closing */