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authorPekka Enberg <penberg@kernel.org>2010-10-24 20:57:05 +0400
committerPekka Enberg <penberg@kernel.org>2010-10-24 20:57:05 +0400
commit6d4121f6c20a0e86231d52f535f1c82423b3326f (patch)
tree5c235cac699ca86b504850aa663ddadde0455a61 /net/dccp/ccids
parent92a5bbc11ff2442a54b2f1d313088c245828ef4e (diff)
parent35da7a307c535f9c2929cae277f3df425c9f9b1e (diff)
downloadlinux-6d4121f6c20a0e86231d52f535f1c82423b3326f.tar.xz
Merge branch 'master' into for-linus
Conflicts: include/linux/percpu.h mm/percpu.c
Diffstat (limited to 'net/dccp/ccids')
-rw-r--r--net/dccp/ccids/Kconfig31
-rw-r--r--net/dccp/ccids/ccid2.c289
-rw-r--r--net/dccp/ccids/ccid2.h35
-rw-r--r--net/dccp/ccids/ccid3.c256
-rw-r--r--net/dccp/ccids/ccid3.h51
-rw-r--r--net/dccp/ccids/lib/loss_interval.c2
-rw-r--r--net/dccp/ccids/lib/packet_history.c39
-rw-r--r--net/dccp/ccids/lib/packet_history.h22
-rw-r--r--net/dccp/ccids/lib/tfrc.h1
-rw-r--r--net/dccp/ccids/lib/tfrc_equation.c14
10 files changed, 279 insertions, 461 deletions
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
index 8408398cd44e..0581143cb800 100644
--- a/net/dccp/ccids/Kconfig
+++ b/net/dccp/ccids/Kconfig
@@ -47,37 +47,6 @@ config IP_DCCP_CCID3_DEBUG
If in doubt, say N.
-config IP_DCCP_CCID3_RTO
- int "Use higher bound for nofeedback timer"
- default 100
- depends on IP_DCCP_CCID3 && EXPERIMENTAL
- ---help---
- Use higher lower bound for nofeedback timer expiration.
-
- The TFRC nofeedback timer normally expires after the maximum of 4
- RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
- with a small RTT this can mean a high processing load and reduced
- performance, since then the nofeedback timer is triggered very
- frequently.
-
- This option enables to set a higher lower bound for the nofeedback
- value. Values in units of milliseconds can be set here.
-
- A value of 0 disables this feature by enforcing the value specified
- in RFC 3448. The following values have been suggested as bounds for
- experimental use:
- * 16-20ms to match the typical multimedia inter-frame interval
- * 100ms as a reasonable compromise [default]
- * 1000ms corresponds to the lower TCP RTO bound (RFC 2988, 2.4)
-
- The default of 100ms is a compromise between a large value for
- efficient DCCP implementations, and a small value to avoid disrupting
- the network in times of congestion.
-
- The purpose of the nofeedback timer is to slow DCCP down when there
- is serious network congestion: experimenting with larger values should
- therefore not be performed on WANs.
-
config IP_DCCP_TFRC_LIB
def_bool y if IP_DCCP_CCID3
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 9b3ae9922be1..d850e291f87c 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -25,59 +25,14 @@
*/
#include <linux/slab.h>
#include "../feat.h"
-#include "../ccid.h"
-#include "../dccp.h"
#include "ccid2.h"
#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
static int ccid2_debug;
#define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
-
-static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hc)
-{
- int len = 0;
- int pipe = 0;
- struct ccid2_seq *seqp = hc->tx_seqh;
-
- /* there is data in the chain */
- if (seqp != hc->tx_seqt) {
- seqp = seqp->ccid2s_prev;
- len++;
- if (!seqp->ccid2s_acked)
- pipe++;
-
- while (seqp != hc->tx_seqt) {
- struct ccid2_seq *prev = seqp->ccid2s_prev;
-
- len++;
- if (!prev->ccid2s_acked)
- pipe++;
-
- /* packets are sent sequentially */
- BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq,
- prev->ccid2s_seq ) >= 0);
- BUG_ON(time_before(seqp->ccid2s_sent,
- prev->ccid2s_sent));
-
- seqp = prev;
- }
- }
-
- BUG_ON(pipe != hc->tx_pipe);
- ccid2_pr_debug("len of chain=%d\n", len);
-
- do {
- seqp = seqp->ccid2s_prev;
- len++;
- } while (seqp != hc->tx_seqh);
-
- ccid2_pr_debug("total len=%d\n", len);
- BUG_ON(len != hc->tx_seqbufc * CCID2_SEQBUF_LEN);
-}
#else
#define ccid2_pr_debug(format, a...)
-#define ccid2_hc_tx_check_sanity(hc)
#endif
static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc)
@@ -156,19 +111,10 @@ static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
dp->dccps_l_ack_ratio = val;
}
-static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hc, long val)
-{
- ccid2_pr_debug("change SRTT to %ld\n", val);
- hc->tx_srtt = val;
-}
-
-static void ccid2_start_rto_timer(struct sock *sk);
-
static void ccid2_hc_tx_rto_expire(unsigned long data)
{
struct sock *sk = (struct sock *)data;
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- long s;
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) {
@@ -178,23 +124,19 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
ccid2_pr_debug("RTO_EXPIRE\n");
- ccid2_hc_tx_check_sanity(hc);
-
/* back-off timer */
hc->tx_rto <<= 1;
+ if (hc->tx_rto > DCCP_RTO_MAX)
+ hc->tx_rto = DCCP_RTO_MAX;
- s = hc->tx_rto / HZ;
- if (s > 60)
- hc->tx_rto = 60 * HZ;
-
- ccid2_start_rto_timer(sk);
+ sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
/* adjust pipe, cwnd etc */
hc->tx_ssthresh = hc->tx_cwnd / 2;
if (hc->tx_ssthresh < 2)
hc->tx_ssthresh = 2;
- hc->tx_cwnd = 1;
- hc->tx_pipe = 0;
+ hc->tx_cwnd = 1;
+ hc->tx_pipe = 0;
/* clear state about stuff we sent */
hc->tx_seqt = hc->tx_seqh;
@@ -204,23 +146,12 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
hc->tx_rpseq = 0;
hc->tx_rpdupack = -1;
ccid2_change_l_ack_ratio(sk, 1);
- ccid2_hc_tx_check_sanity(hc);
out:
bh_unlock_sock(sk);
sock_put(sk);
}
-static void ccid2_start_rto_timer(struct sock *sk)
-{
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-
- ccid2_pr_debug("setting RTO timeout=%ld\n", hc->tx_rto);
-
- BUG_ON(timer_pending(&hc->tx_rtotimer));
- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
-}
-
-static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
+static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
@@ -230,7 +161,7 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
hc->tx_seqh->ccid2s_seq = dp->dccps_gss;
hc->tx_seqh->ccid2s_acked = 0;
- hc->tx_seqh->ccid2s_sent = jiffies;
+ hc->tx_seqh->ccid2s_sent = ccid2_time_stamp;
next = hc->tx_seqh->ccid2s_next;
/* check if we need to alloc more space */
@@ -296,23 +227,20 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
}
#endif
- /* setup RTO timer */
- if (!timer_pending(&hc->tx_rtotimer))
- ccid2_start_rto_timer(sk);
+ sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
do {
struct ccid2_seq *seqp = hc->tx_seqt;
while (seqp != hc->tx_seqh) {
- ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
+ ccid2_pr_debug("out seq=%llu acked=%d time=%u\n",
(unsigned long long)seqp->ccid2s_seq,
seqp->ccid2s_acked, seqp->ccid2s_sent);
seqp = seqp->ccid2s_next;
}
} while (0);
ccid2_pr_debug("=========\n");
- ccid2_hc_tx_check_sanity(hc);
#endif
}
@@ -378,17 +306,87 @@ out_invalid_option:
return -1;
}
-static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
+/**
+ * ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm
+ * This code is almost identical with TCP's tcp_rtt_estimator(), since
+ * - it has a higher sampling frequency (recommended by RFC 1323),
+ * - the RTO does not collapse into RTT due to RTTVAR going towards zero,
+ * - it is simple (cf. more complex proposals such as Eifel timer or research
+ * which suggests that the gain should be set according to window size),
+ * - in tests it was found to work well with CCID2 [gerrit].
+ */
+static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
{
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+ long m = mrtt ? : 1;
- sk_stop_timer(sk, &hc->tx_rtotimer);
- ccid2_pr_debug("deleted RTO timer\n");
+ if (hc->tx_srtt == 0) {
+ /* First measurement m */
+ hc->tx_srtt = m << 3;
+ hc->tx_mdev = m << 1;
+
+ hc->tx_mdev_max = max(hc->tx_mdev, tcp_rto_min(sk));
+ hc->tx_rttvar = hc->tx_mdev_max;
+
+ hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
+ } else {
+ /* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */
+ m -= (hc->tx_srtt >> 3);
+ hc->tx_srtt += m;
+
+ /* Similarly, update scaled mdev with regard to |m| */
+ if (m < 0) {
+ m = -m;
+ m -= (hc->tx_mdev >> 2);
+ /*
+ * This neutralises RTO increase when RTT < SRTT - mdev
+ * (see P. Sarolahti, A. Kuznetsov,"Congestion Control
+ * in Linux TCP", USENIX 2002, pp. 49-62).
+ */
+ if (m > 0)
+ m >>= 3;
+ } else {
+ m -= (hc->tx_mdev >> 2);
+ }
+ hc->tx_mdev += m;
+
+ if (hc->tx_mdev > hc->tx_mdev_max) {
+ hc->tx_mdev_max = hc->tx_mdev;
+ if (hc->tx_mdev_max > hc->tx_rttvar)
+ hc->tx_rttvar = hc->tx_mdev_max;
+ }
+
+ /*
+ * Decay RTTVAR at most once per flight, exploiting that
+ * 1) pipe <= cwnd <= Sequence_Window = W (RFC 4340, 7.5.2)
+ * 2) AWL = GSS-W+1 <= GAR <= GSS (RFC 4340, 7.5.1)
+ * GAR is a useful bound for FlightSize = pipe.
+ * AWL is probably too low here, as it over-estimates pipe.
+ */
+ if (after48(dccp_sk(sk)->dccps_gar, hc->tx_rtt_seq)) {
+ if (hc->tx_mdev_max < hc->tx_rttvar)
+ hc->tx_rttvar -= (hc->tx_rttvar -
+ hc->tx_mdev_max) >> 2;
+ hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
+ hc->tx_mdev_max = tcp_rto_min(sk);
+ }
+ }
+
+ /*
+ * Set RTO from SRTT and RTTVAR
+ * As in TCP, 4 * RTTVAR >= TCP_RTO_MIN, giving a minimum RTO of 200 ms.
+ * This agrees with RFC 4341, 5:
+ * "Because DCCP does not retransmit data, DCCP does not require
+ * TCP's recommended minimum timeout of one second".
+ */
+ hc->tx_rto = (hc->tx_srtt >> 3) + hc->tx_rttvar;
+
+ if (hc->tx_rto > DCCP_RTO_MAX)
+ hc->tx_rto = DCCP_RTO_MAX;
}
-static inline void ccid2_new_ack(struct sock *sk,
- struct ccid2_seq *seqp,
- unsigned int *maxincr)
+static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp,
+ unsigned int *maxincr)
{
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
@@ -402,93 +400,27 @@ static inline void ccid2_new_ack(struct sock *sk,
hc->tx_cwnd += 1;
hc->tx_packets_acked = 0;
}
-
- /* update RTO */
- if (hc->tx_srtt == -1 ||
- time_after(jiffies, hc->tx_lastrtt + hc->tx_srtt)) {
- unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
- int s;
-
- /* first measurement */
- if (hc->tx_srtt == -1) {
- ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
- r, jiffies,
- (unsigned long long)seqp->ccid2s_seq);
- ccid2_change_srtt(hc, r);
- hc->tx_rttvar = r >> 1;
- } else {
- /* RTTVAR */
- long tmp = hc->tx_srtt - r;
- long srtt;
-
- if (tmp < 0)
- tmp *= -1;
-
- tmp >>= 2;
- hc->tx_rttvar *= 3;
- hc->tx_rttvar >>= 2;
- hc->tx_rttvar += tmp;
-
- /* SRTT */
- srtt = hc->tx_srtt;
- srtt *= 7;
- srtt >>= 3;
- tmp = r >> 3;
- srtt += tmp;
- ccid2_change_srtt(hc, srtt);
- }
- s = hc->tx_rttvar << 2;
- /* clock granularity is 1 when based on jiffies */
- if (!s)
- s = 1;
- hc->tx_rto = hc->tx_srtt + s;
-
- /* must be at least a second */
- s = hc->tx_rto / HZ;
- /* DCCP doesn't require this [but I like it cuz my code sux] */
-#if 1
- if (s < 1)
- hc->tx_rto = HZ;
-#endif
- /* max 60 seconds */
- if (s > 60)
- hc->tx_rto = HZ * 60;
-
- hc->tx_lastrtt = jiffies;
-
- ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
- hc->tx_srtt, hc->tx_rttvar,
- hc->tx_rto, HZ, r);
- }
-
- /* we got a new ack, so re-start RTO timer */
- ccid2_hc_tx_kill_rto_timer(sk);
- ccid2_start_rto_timer(sk);
-}
-
-static void ccid2_hc_tx_dec_pipe(struct sock *sk)
-{
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-
- if (hc->tx_pipe == 0)
- DCCP_BUG("pipe == 0");
- else
- hc->tx_pipe--;
-
- if (hc->tx_pipe == 0)
- ccid2_hc_tx_kill_rto_timer(sk);
+ /*
+ * FIXME: RTT is sampled several times per acknowledgment (for each
+ * entry in the Ack Vector), instead of once per Ack (as in TCP SACK).
+ * This causes the RTT to be over-estimated, since the older entries
+ * in the Ack Vector have earlier sending times.
+ * The cleanest solution is to not use the ccid2s_sent field at all
+ * and instead use DCCP timestamps: requires changes in other places.
+ */
+ ccid2_rtt_estimator(sk, ccid2_time_stamp - seqp->ccid2s_sent);
}
static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
{
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- if (time_before(seqp->ccid2s_sent, hc->tx_last_cong)) {
+ if ((s32)(seqp->ccid2s_sent - hc->tx_last_cong) < 0) {
ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
return;
}
- hc->tx_last_cong = jiffies;
+ hc->tx_last_cong = ccid2_time_stamp;
hc->tx_cwnd = hc->tx_cwnd / 2 ? : 1U;
hc->tx_ssthresh = max(hc->tx_cwnd, 2U);
@@ -510,7 +442,6 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
int done = 0;
unsigned int maxincr = 0;
- ccid2_hc_tx_check_sanity(hc);
/* check reverse path congestion */
seqno = DCCP_SKB_CB(skb)->dccpd_seq;
@@ -620,7 +551,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
seqp->ccid2s_acked = 1;
ccid2_pr_debug("Got ack for %llu\n",
(unsigned long long)seqp->ccid2s_seq);
- ccid2_hc_tx_dec_pipe(sk);
+ hc->tx_pipe--;
}
if (seqp == hc->tx_seqt) {
done = 1;
@@ -677,7 +608,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
* one ack vector.
*/
ccid2_congestion_event(sk, seqp);
- ccid2_hc_tx_dec_pipe(sk);
+ hc->tx_pipe--;
}
if (seqp == hc->tx_seqt)
break;
@@ -695,7 +626,11 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
hc->tx_seqt = hc->tx_seqt->ccid2s_next;
}
- ccid2_hc_tx_check_sanity(hc);
+ /* restart RTO timer if not all outstanding data has been acked */
+ if (hc->tx_pipe == 0)
+ sk_stop_timer(sk, &hc->tx_rtotimer);
+ else
+ sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
}
static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -707,12 +642,8 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
/* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */
hc->tx_ssthresh = ~0U;
- /*
- * RFC 4341, 5: "The cwnd parameter is initialized to at most four
- * packets for new connections, following the rules from [RFC3390]".
- * We need to convert the bytes of RFC3390 into the packets of RFC 4341.
- */
- hc->tx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U);
+ /* Use larger initial windows (RFC 4341, section 5). */
+ hc->tx_cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache);
/* Make sure that Ack Ratio is enabled and within bounds. */
max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 2);
@@ -723,15 +654,11 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
if (ccid2_hc_tx_alloc_seq(hc))
return -ENOMEM;
- hc->tx_rto = 3 * HZ;
- ccid2_change_srtt(hc, -1);
- hc->tx_rttvar = -1;
+ hc->tx_rto = DCCP_TIMEOUT_INIT;
hc->tx_rpdupack = -1;
- hc->tx_last_cong = jiffies;
+ hc->tx_last_cong = ccid2_time_stamp;
setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire,
(unsigned long)sk);
-
- ccid2_hc_tx_check_sanity(hc);
return 0;
}
@@ -740,7 +667,7 @@ static void ccid2_hc_tx_exit(struct sock *sk)
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
int i;
- ccid2_hc_tx_kill_rto_timer(sk);
+ sk_stop_timer(sk, &hc->tx_rtotimer);
for (i = 0; i < hc->tx_seqbufc; i++)
kfree(hc->tx_seqbuf[i]);
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
index 1ec6a30103bb..9731c2dc1487 100644
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
@@ -18,18 +18,23 @@
#ifndef _DCCP_CCID2_H_
#define _DCCP_CCID2_H_
-#include <linux/dccp.h>
#include <linux/timer.h>
#include <linux/types.h>
#include "../ccid.h"
+#include "../dccp.h"
+
+/*
+ * CCID-2 timestamping faces the same issues as TCP timestamping.
+ * Hence we reuse/share as much of the code as possible.
+ */
+#define ccid2_time_stamp tcp_time_stamp
+
/* NUMDUPACK parameter from RFC 4341, p. 6 */
#define NUMDUPACK 3
-struct sock;
-
struct ccid2_seq {
u64 ccid2s_seq;
- unsigned long ccid2s_sent;
+ u32 ccid2s_sent;
int ccid2s_acked;
struct ccid2_seq *ccid2s_prev;
struct ccid2_seq *ccid2s_next;
@@ -42,7 +47,12 @@ struct ccid2_seq {
* struct ccid2_hc_tx_sock - CCID2 TX half connection
* @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
* @tx_packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
- * @tx_lastrtt: time RTT was last measured
+ * @tx_srtt: smoothed RTT estimate, scaled by 2^3
+ * @tx_mdev: smoothed RTT variation, scaled by 2^2
+ * @tx_mdev_max: maximum of @mdev during one flight
+ * @tx_rttvar: moving average/maximum of @mdev_max
+ * @tx_rto: RTO value deriving from SRTT and RTTVAR (RFC 2988)
+ * @tx_rtt_seq: to decay RTTVAR at most once per flight
* @tx_rpseq: last consecutive seqno
* @tx_rpdupack: dupacks since rpseq
*/
@@ -55,14 +65,19 @@ struct ccid2_hc_tx_sock {
int tx_seqbufc;
struct ccid2_seq *tx_seqh;
struct ccid2_seq *tx_seqt;
- long tx_rto;
- long tx_srtt;
- long tx_rttvar;
- unsigned long tx_lastrtt;
+
+ /* RTT measurement: variables/principles are the same as in TCP */
+ u32 tx_srtt,
+ tx_mdev,
+ tx_mdev_max,
+ tx_rttvar,
+ tx_rto;
+ u64 tx_rtt_seq:48;
struct timer_list tx_rtotimer;
+
u64 tx_rpseq;
int tx_rpdupack;
- unsigned long tx_last_cong;
+ u32 tx_last_cong;
u64 tx_high_ack;
};
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 95f752986497..3060a60ed5ab 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -54,7 +54,6 @@ static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
[TFRC_SSTATE_NO_SENT] = "NO_SENT",
[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
[TFRC_SSTATE_FBACK] = "FBACK",
- [TFRC_SSTATE_TERM] = "TERM",
};
return ccid3_state_names[state];
@@ -91,19 +90,16 @@ static inline u64 rfc3390_initial_rate(struct sock *sk)
return scaled_div(w_init << 6, hc->tx_rtt);
}
-/*
- * Recalculate t_ipi and delta (should be called whenever X changes)
+/**
+ * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst
+ * This respects the granularity of X_inst (64 * bytes/second).
*/
static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
{
- /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
- /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
- hc->tx_delta = min_t(u32, hc->tx_t_ipi / 2, TFRC_OPSYS_HALF_TIME_GRAN);
-
- ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n", hc->tx_t_ipi,
- hc->tx_delta, hc->tx_s, (unsigned)(hc->tx_x >> 6));
+ ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
+ hc->tx_s, (unsigned)(hc->tx_x >> 6));
}
static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
@@ -211,16 +207,19 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
ccid3_tx_state_name(hc->tx_state));
+ /* Ignore and do not restart after leaving the established state */
+ if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
+ goto out;
+
+ /* Reset feedback state to "no feedback received" */
if (hc->tx_state == TFRC_SSTATE_FBACK)
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
- else if (hc->tx_state != TFRC_SSTATE_NO_FBACK)
- goto out;
/*
* Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
+ * RTO is 0 if and only if no feedback has been received yet.
*/
- if (hc->tx_t_rto == 0 || /* no feedback received yet */
- hc->tx_p == 0) {
+ if (hc->tx_t_rto == 0 || hc->tx_p == 0) {
/* halve send rate directly */
hc->tx_x = max(hc->tx_x / 2,
@@ -256,7 +255,7 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
* Set new timeout for the nofeedback timer.
* See comments in packet_recv() regarding the value of t_RTO.
*/
- if (unlikely(hc->tx_t_rto == 0)) /* no feedback yet */
+ if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */
t_nfb = TFRC_INITIAL_TIMEOUT;
else
t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
@@ -290,8 +289,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
if (unlikely(skb->len == 0))
return -EBADMSG;
- switch (hc->tx_state) {
- case TFRC_SSTATE_NO_SENT:
+ if (hc->tx_state == TFRC_SSTATE_NO_SENT) {
sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies +
usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
hc->tx_last_win_count = 0;
@@ -326,27 +324,22 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
ccid3_update_send_interval(hc);
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
- break;
- case TFRC_SSTATE_NO_FBACK:
- case TFRC_SSTATE_FBACK:
+
+ } else {
delay = ktime_us_delta(hc->tx_t_nom, now);
ccid3_pr_debug("delay=%ld\n", (long)delay);
/*
- * Scheduling of packet transmissions [RFC 3448, 4.6]
+ * Scheduling of packet transmissions (RFC 5348, 8.3)
*
* if (t_now > t_nom - delta)
* // send the packet now
* else
* // send the packet in (t_nom - t_now) milliseconds.
*/
- if (delay - (s64)hc->tx_delta >= 1000)
- return (u32)delay / 1000L;
+ if (delay >= TFRC_T_DELTA)
+ return (u32)delay / USEC_PER_MSEC;
ccid3_hc_tx_update_win_count(hc, now);
- break;
- case TFRC_SSTATE_TERM:
- DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
- return -EINVAL;
}
/* prepare to send now (add options etc.) */
@@ -358,8 +351,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
return 0;
}
-static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
- unsigned int len)
+static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
{
struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
@@ -372,48 +364,34 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
- struct ccid3_options_received *opt_recv;
+ struct tfrc_tx_hist_entry *acked;
ktime_t now;
unsigned long t_nfb;
- u32 pinv, r_sample;
+ u32 r_sample;
/* we are only interested in ACKs */
if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
return;
- /* ... and only in the established state */
- if (hc->tx_state != TFRC_SSTATE_FBACK &&
- hc->tx_state != TFRC_SSTATE_NO_FBACK)
- return;
-
- opt_recv = &hc->tx_options_received;
- now = ktime_get_real();
-
- /* Estimate RTT from history if ACK number is valid */
- r_sample = tfrc_tx_hist_rtt(hc->tx_hist,
- DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
- if (r_sample == 0) {
- DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
- dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
- (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
- return;
- }
-
- /* Update receive rate in units of 64 * bytes/second */
- hc->tx_x_recv = opt_recv->ccid3or_receive_rate;
- hc->tx_x_recv <<= 6;
-
- /* Update loss event rate (which is scaled by 1e6) */
- pinv = opt_recv->ccid3or_loss_event_rate;
- if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
- hc->tx_p = 0;
- else /* can not exceed 100% */
- hc->tx_p = scaled_div(1, pinv);
/*
- * Validate new RTT sample and update moving average
+ * Locate the acknowledged packet in the TX history.
+ *
+ * Returning "entry not found" here can for instance happen when
+ * - the host has not sent out anything (e.g. a passive server),
+ * - the Ack is outdated (packet with higher Ack number was received),
+ * - it is a bogus Ack (for a packet not sent on this connection).
*/
- r_sample = dccp_sample_rtt(sk, r_sample);
+ acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
+ if (acked == NULL)
+ return;
+ /* For the sake of RTT sampling, ignore/remove all older entries */
+ tfrc_tx_hist_purge(&acked->next);
+
+ /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
+ now = ktime_get_real();
+ r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
+
/*
* Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
*/
@@ -461,13 +439,12 @@ done_computing_x:
sk->sk_write_space(sk);
/*
- * Update timeout interval for the nofeedback timer.
- * We use a configuration option to increase the lower bound.
- * This can help avoid triggering the nofeedback timer too
- * often ('spinning') on LANs with small RTTs.
+ * Update timeout interval for the nofeedback timer. In order to control
+ * rate halving on networks with very low RTTs (<= 1 ms), use per-route
+ * tunable RTAX_RTO_MIN value as the lower bound.
*/
- hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt, (CONFIG_IP_DCCP_CCID3_RTO *
- (USEC_PER_SEC / 1000)));
+ hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
+ USEC_PER_SEC/HZ * tcp_rto_min(sk));
/*
* Schedule no feedback timer to expire in
* max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
@@ -482,66 +459,41 @@ done_computing_x:
jiffies + usecs_to_jiffies(t_nfb));
}
-static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
- unsigned char len, u16 idx,
- unsigned char *value)
+static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+ u8 option, u8 *optval, u8 optlen)
{
- int rc = 0;
- const struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
- struct ccid3_options_received *opt_recv;
__be32 opt_val;
- opt_recv = &hc->tx_options_received;
-
- if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
- opt_recv->ccid3or_seqno = dp->dccps_gsr;
- opt_recv->ccid3or_loss_event_rate = ~0;
- opt_recv->ccid3or_loss_intervals_idx = 0;
- opt_recv->ccid3or_loss_intervals_len = 0;
- opt_recv->ccid3or_receive_rate = 0;
- }
-
switch (option) {
+ case TFRC_OPT_RECEIVE_RATE:
case TFRC_OPT_LOSS_EVENT_RATE:
- if (unlikely(len != 4)) {
- DCCP_WARN("%s(%p), invalid len %d "
- "for TFRC_OPT_LOSS_EVENT_RATE\n",
- dccp_role(sk), sk, len);
- rc = -EINVAL;
- } else {
- opt_val = get_unaligned((__be32 *)value);
- opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
- ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
- dccp_role(sk), sk,
- opt_recv->ccid3or_loss_event_rate);
+ /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */
+ if (packet_type == DCCP_PKT_DATA)
+ break;
+ if (unlikely(optlen != 4)) {
+ DCCP_WARN("%s(%p), invalid len %d for %u\n",
+ dccp_role(sk), sk, optlen, option);
+ return -EINVAL;
}
- break;
- case TFRC_OPT_LOSS_INTERVALS:
- opt_recv->ccid3or_loss_intervals_idx = idx;
- opt_recv->ccid3or_loss_intervals_len = len;
- ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
- dccp_role(sk), sk,
- opt_recv->ccid3or_loss_intervals_idx,
- opt_recv->ccid3or_loss_intervals_len);
- break;
- case TFRC_OPT_RECEIVE_RATE:
- if (unlikely(len != 4)) {
- DCCP_WARN("%s(%p), invalid len %d "
- "for TFRC_OPT_RECEIVE_RATE\n",
- dccp_role(sk), sk, len);
- rc = -EINVAL;
- } else {
- opt_val = get_unaligned((__be32 *)value);
- opt_recv->ccid3or_receive_rate = ntohl(opt_val);
+ opt_val = ntohl(get_unaligned((__be32 *)optval));
+
+ if (option == TFRC_OPT_RECEIVE_RATE) {
+ /* Receive Rate is kept in units of 64 bytes/second */
+ hc->tx_x_recv = opt_val;
+ hc->tx_x_recv <<= 6;
+
ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
- dccp_role(sk), sk,
- opt_recv->ccid3or_receive_rate);
+ dccp_role(sk), sk, opt_val);
+ } else {
+ /* Update the fixpoint Loss Event Rate fraction */
+ hc->tx_p = tfrc_invert_loss_event_rate(opt_val);
+
+ ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
+ dccp_role(sk), sk, opt_val);
}
- break;
}
-
- return rc;
+ return 0;
}
static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -559,42 +511,36 @@ static void ccid3_hc_tx_exit(struct sock *sk)
{
struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
- ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
sk_stop_timer(sk, &hc->tx_no_feedback_timer);
-
tfrc_tx_hist_purge(&hc->tx_hist);
}
static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
{
- struct ccid3_hc_tx_sock *hc;
-
- /* Listen socks doesn't have a private CCID block */
- if (sk->sk_state == DCCP_LISTEN)
- return;
-
- hc = ccid3_hc_tx_sk(sk);
- info->tcpi_rto = hc->tx_t_rto;
- info->tcpi_rtt = hc->tx_rtt;
+ info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto;
+ info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt;
}
static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
u32 __user *optval, int __user *optlen)
{
- const struct ccid3_hc_tx_sock *hc;
+ const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
+ struct tfrc_tx_info tfrc;
const void *val;
- /* Listen socks doesn't have a private CCID block */
- if (sk->sk_state == DCCP_LISTEN)
- return -EINVAL;
-
- hc = ccid3_hc_tx_sk(sk);
switch (optname) {
case DCCP_SOCKOPT_CCID_TX_INFO:
- if (len < sizeof(hc->tx_tfrc))
+ if (len < sizeof(tfrc))
return -EINVAL;
- len = sizeof(hc->tx_tfrc);
- val = &hc->tx_tfrc;
+ tfrc.tfrctx_x = hc->tx_x;
+ tfrc.tfrctx_x_recv = hc->tx_x_recv;
+ tfrc.tfrctx_x_calc = hc->tx_x_calc;
+ tfrc.tfrctx_rtt = hc->tx_rtt;
+ tfrc.tfrctx_p = hc->tx_p;
+ tfrc.tfrctx_rto = hc->tx_t_rto;
+ tfrc.tfrctx_ipi = hc->tx_t_ipi;
+ len = sizeof(tfrc);
+ val = &tfrc;
break;
default:
return -ENOPROTOOPT;
@@ -624,7 +570,6 @@ static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
static const char *const ccid3_rx_state_names[] = {
[TFRC_RSTATE_NO_DATA] = "NO_DATA",
[TFRC_RSTATE_DATA] = "DATA",
- [TFRC_RSTATE_TERM] = "TERM",
};
return ccid3_rx_state_names[state];
@@ -650,14 +595,9 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
{
struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
struct dccp_sock *dp = dccp_sk(sk);
- ktime_t now;
+ ktime_t now = ktime_get_real();
s64 delta = 0;
- if (unlikely(hc->rx_state == TFRC_RSTATE_TERM))
- return;
-
- now = ktime_get_real();
-
switch (fbtype) {
case CCID3_FBACK_INITIAL:
hc->rx_x_recv = 0;
@@ -701,14 +641,12 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
{
- const struct ccid3_hc_rx_sock *hc;
+ const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
__be32 x_recv, pinv;
if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
return 0;
- hc = ccid3_hc_rx_sk(sk);
-
if (dccp_packet_without_ack(skb))
return 0;
@@ -749,10 +687,11 @@ static u32 ccid3_first_li(struct sock *sk)
x_recv = scaled_div32(hc->rx_bytes_recv, delta);
if (x_recv == 0) { /* would also trigger divide-by-zero */
DCCP_WARN("X_recv==0\n");
- if ((x_recv = hc->rx_x_recv) == 0) {
+ if (hc->rx_x_recv == 0) {
DCCP_BUG("stored value of X_recv is zero");
return ~0U;
}
+ x_recv = hc->rx_x_recv;
}
fval = scaled_div(hc->rx_s, hc->rx_rtt);
@@ -862,46 +801,31 @@ static void ccid3_hc_rx_exit(struct sock *sk)
{
struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
- ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
-
tfrc_rx_hist_purge(&hc->rx_hist);
tfrc_lh_cleanup(&hc->rx_li_hist);
}
static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
{
- const struct ccid3_hc_rx_sock *hc;
-
- /* Listen socks doesn't have a private CCID block */
- if (sk->sk_state == DCCP_LISTEN)
- return;
-
- hc = ccid3_hc_rx_sk(sk);
- info->tcpi_ca_state = hc->rx_state;
+ info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state;
info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
- info->tcpi_rcv_rtt = hc->rx_rtt;
+ info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_rtt;
}
static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
u32 __user *optval, int __user *optlen)
{
- const struct ccid3_hc_rx_sock *hc;
+ const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
struct tfrc_rx_info rx_info;
const void *val;
- /* Listen socks doesn't have a private CCID block */
- if (sk->sk_state == DCCP_LISTEN)
- return -EINVAL;
-
- hc = ccid3_hc_rx_sk(sk);
switch (optname) {
case DCCP_SOCKOPT_CCID_RX_INFO:
if (len < sizeof(rx_info))
return -EINVAL;
rx_info.tfrcrx_x_recv = hc->rx_x_recv;
rx_info.tfrcrx_rtt = hc->rx_rtt;
- rx_info.tfrcrx_p = hc->rx_pinv == 0 ? ~0U :
- scaled_div(1, hc->rx_pinv);
+ rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hc->rx_pinv);
len = sizeof(rx_info);
val = &rx_info;
break;
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index 032635776653..1a9933c29672 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -42,35 +42,36 @@
#include "lib/tfrc.h"
#include "../ccid.h"
-/* Two seconds as per RFC 3448 4.2 */
+/* Two seconds as per RFC 5348, 4.2 */
#define TFRC_INITIAL_TIMEOUT (2 * USEC_PER_SEC)
-/* In usecs - half the scheduling granularity as per RFC3448 4.6 */
-#define TFRC_OPSYS_HALF_TIME_GRAN (USEC_PER_SEC / (2 * HZ))
-
/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
#define TFRC_T_MBI 64
+/*
+ * The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
+ * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
+ * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
+ * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
+ * when using the constant t_delta = t_gran / 2 = %USEC_PER_SEC / (2 * HZ).
+ */
+#if (HZ >= 500)
+# define TFRC_T_DELTA USEC_PER_MSEC
+#else
+# define TFRC_T_DELTA (USEC_PER_SEC / (2 * HZ))
+#endif
+
enum ccid3_options {
TFRC_OPT_LOSS_EVENT_RATE = 192,
TFRC_OPT_LOSS_INTERVALS = 193,
TFRC_OPT_RECEIVE_RATE = 194,
};
-struct ccid3_options_received {
- u64 ccid3or_seqno:48,
- ccid3or_loss_intervals_idx:16;
- u16 ccid3or_loss_intervals_len;
- u32 ccid3or_loss_event_rate;
- u32 ccid3or_receive_rate;
-};
-
/* TFRC sender states */
enum ccid3_hc_tx_states {
TFRC_SSTATE_NO_SENT = 1,
TFRC_SSTATE_NO_FBACK,
TFRC_SSTATE_FBACK,
- TFRC_SSTATE_TERM,
};
/**
@@ -90,19 +91,16 @@ enum ccid3_hc_tx_states {
* @tx_no_feedback_timer: Handle to no feedback timer
* @tx_t_ld: Time last doubled during slow start
* @tx_t_nom: Nominal send time of next packet
- * @tx_delta: Send timer delta (RFC 3448, 4.6) in usecs
* @tx_hist: Packet history
- * @tx_options_received: Parsed set of retrieved options
*/
struct ccid3_hc_tx_sock {
- struct tfrc_tx_info tx_tfrc;
-#define tx_x tx_tfrc.tfrctx_x
-#define tx_x_recv tx_tfrc.tfrctx_x_recv
-#define tx_x_calc tx_tfrc.tfrctx_x_calc
-#define tx_rtt tx_tfrc.tfrctx_rtt
-#define tx_p tx_tfrc.tfrctx_p
-#define tx_t_rto tx_tfrc.tfrctx_rto
-#define tx_t_ipi tx_tfrc.tfrctx_ipi
+ u64 tx_x;
+ u64 tx_x_recv;
+ u32 tx_x_calc;
+ u32 tx_rtt;
+ u32 tx_p;
+ u32 tx_t_rto;
+ u32 tx_t_ipi;
u16 tx_s;
enum ccid3_hc_tx_states tx_state:8;
u8 tx_last_win_count;
@@ -110,9 +108,7 @@ struct ccid3_hc_tx_sock {
struct timer_list tx_no_feedback_timer;
ktime_t tx_t_ld;
ktime_t tx_t_nom;
- u32 tx_delta;
struct tfrc_tx_hist_entry *tx_hist;
- struct ccid3_options_received tx_options_received;
};
static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
@@ -126,21 +122,16 @@ static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
enum ccid3_hc_rx_states {
TFRC_RSTATE_NO_DATA = 1,
TFRC_RSTATE_DATA,
- TFRC_RSTATE_TERM = 127,
};
/**
* struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
- * @rx_x_recv: Receiver estimate of send rate (RFC 3448 4.3)
- * @rx_rtt: Receiver estimate of rtt (non-standard)
- * @rx_p: Current loss event rate (RFC 3448 5.4)
* @rx_last_counter: Tracks window counter (RFC 4342, 8.1)
* @rx_state: Receiver state, one of %ccid3_hc_rx_states
* @rx_bytes_recv: Total sum of DCCP payload bytes
* @rx_x_recv: Receiver estimate of send rate (RFC 3448, sec. 4.3)
* @rx_rtt: Receiver estimate of RTT
* @rx_tstamp_last_feedback: Time at which last feedback was sent
- * @rx_tstamp_last_ack: Time at which last feedback was sent
* @rx_hist: Packet history (loss detection + RTT sampling)
* @rx_li_hist: Loss Interval database
* @rx_s: Received packet size in bytes
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index 8fc3cbf79071..497723c4d4bb 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -116,7 +116,7 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
cur->li_length = len;
tfrc_lh_calc_i_mean(lh);
- return (lh->i_mean < old_i_mean);
+ return lh->i_mean < old_i_mean;
}
/* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 3a4f414e94a0..de8fe294bf0b 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -38,18 +38,6 @@
#include "packet_history.h"
#include "../../dccp.h"
-/**
- * tfrc_tx_hist_entry - Simple singly-linked TX history list
- * @next: next oldest entry (LIFO order)
- * @seqno: sequence number of this entry
- * @stamp: send time of packet with sequence number @seqno
- */
-struct tfrc_tx_hist_entry {
- struct tfrc_tx_hist_entry *next;
- u64 seqno;
- ktime_t stamp;
-};
-
/*
* Transmitter History Routines
*/
@@ -71,15 +59,6 @@ void tfrc_tx_packet_history_exit(void)
}
}
-static struct tfrc_tx_hist_entry *
- tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
-{
- while (head != NULL && head->seqno != seqno)
- head = head->next;
-
- return head;
-}
-
int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
{
struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any());
@@ -107,24 +86,6 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
*headp = NULL;
}
-u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
- const ktime_t now)
-{
- u32 rtt = 0;
- struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno);
-
- if (packet != NULL) {
- rtt = ktime_us_delta(now, packet->stamp);
- /*
- * Garbage-collect older (irrelevant) entries:
- */
- tfrc_tx_hist_purge(&packet->next);
- }
-
- return rtt;
-}
-
-
/*
* Receiver History Routines
*/
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 7df6c5299999..7ee4a9d9d335 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -40,12 +40,28 @@
#include <linux/slab.h>
#include "tfrc.h"
-struct tfrc_tx_hist_entry;
+/**
+ * tfrc_tx_hist_entry - Simple singly-linked TX history list
+ * @next: next oldest entry (LIFO order)
+ * @seqno: sequence number of this entry
+ * @stamp: send time of packet with sequence number @seqno
+ */
+struct tfrc_tx_hist_entry {
+ struct tfrc_tx_hist_entry *next;
+ u64 seqno;
+ ktime_t stamp;
+};
+
+static inline struct tfrc_tx_hist_entry *
+ tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
+{
+ while (head != NULL && head->seqno != seqno)
+ head = head->next;
+ return head;
+}
extern int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
-extern u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
- const u64 seqno, const ktime_t now);
/* Subtraction a-b modulo-16, respects circular wrap-around */
#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index 01bb48e96c2e..f8ee3f549770 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -57,6 +57,7 @@ static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
extern u32 tfrc_calc_x(u16 s, u32 R, u32 p);
extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
+extern u32 tfrc_invert_loss_event_rate(u32 loss_event_rate);
extern int tfrc_tx_packet_history_init(void);
extern void tfrc_tx_packet_history_exit(void);
diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c
index 22ca1cf0eb55..a052a4377e26 100644
--- a/net/dccp/ccids/lib/tfrc_equation.c
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -687,3 +687,17 @@ u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
index = tfrc_binsearch(fvalue, 0);
return (index + 1) * 1000000 / TFRC_CALC_X_ARRSIZE;
}
+
+/**
+ * tfrc_invert_loss_event_rate - Compute p so that 10^6 corresponds to 100%
+ * When @loss_event_rate is large, there is a chance that p is truncated to 0.
+ * To avoid re-entering slow-start in that case, we set p = TFRC_SMALLEST_P > 0.
+ */
+u32 tfrc_invert_loss_event_rate(u32 loss_event_rate)
+{
+ if (loss_event_rate == UINT_MAX) /* see RFC 4342, 8.5 */
+ return 0;
+ if (unlikely(loss_event_rate == 0)) /* map 1/0 into 100% */
+ return 1000000;
+ return max_t(u32, scaled_div(1, loss_event_rate), TFRC_SMALLEST_P);
+}