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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2008-09-09 13:27:22 +0200
committerGerrit Renker <gerrit@erg.abdn.ac.uk>2008-09-09 13:27:22 +0200
commit410e27a49bb98bc7fa3ff5fc05cc313817b9f253 (patch)
tree88bb1fcf84f9ebfa4299c9a8dcd9e6330b358446 /net/dccp/ccids
parent0a68a20cc3eafa73bb54097c28b921147d7d3685 (diff)
This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp"
as it accentally contained the wrong set of patches. These will be submitted separately. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'net/dccp/ccids')
-rw-r--r--net/dccp/ccids/Kconfig30
-rw-r--r--net/dccp/ccids/ccid2.c622
-rw-r--r--net/dccp/ccids/ccid2.h63
-rw-r--r--net/dccp/ccids/ccid3.c762
-rw-r--r--net/dccp/ccids/ccid3.h153
-rw-r--r--net/dccp/ccids/lib/loss_interval.c30
-rw-r--r--net/dccp/ccids/lib/loss_interval.h4
-rw-r--r--net/dccp/ccids/lib/packet_history.c282
-rw-r--r--net/dccp/ccids/lib/packet_history.h78
-rw-r--r--net/dccp/ccids/lib/tfrc.h16
-rw-r--r--net/dccp/ccids/lib/tfrc_equation.c29
11 files changed, 1116 insertions, 953 deletions
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
index fb168be2cb43..12275943eab8 100644
--- a/net/dccp/ccids/Kconfig
+++ b/net/dccp/ccids/Kconfig
@@ -1,8 +1,10 @@
menu "DCCP CCIDs Configuration (EXPERIMENTAL)"
+ depends on EXPERIMENTAL
config IP_DCCP_CCID2
- tristate "CCID2 (TCP-Like)"
+ tristate "CCID2 (TCP-Like) (EXPERIMENTAL)"
def_tristate IP_DCCP
+ select IP_DCCP_ACKVEC
---help---
CCID 2, TCP-like Congestion Control, denotes Additive Increase,
Multiplicative Decrease (AIMD) congestion control with behavior
@@ -34,7 +36,7 @@ config IP_DCCP_CCID2_DEBUG
If in doubt, say N.
config IP_DCCP_CCID3
- tristate "CCID3 (TCP-Friendly)"
+ tristate "CCID3 (TCP-Friendly) (EXPERIMENTAL)"
def_tristate IP_DCCP
select IP_DCCP_TFRC_LIB
---help---
@@ -62,9 +64,9 @@ config IP_DCCP_CCID3
If in doubt, say M.
-if IP_DCCP_CCID3
config IP_DCCP_CCID3_DEBUG
bool "CCID3 debugging messages"
+ depends on IP_DCCP_CCID3
---help---
Enable CCID3-specific debugging messages.
@@ -74,29 +76,10 @@ config IP_DCCP_CCID3_DEBUG
If in doubt, say N.
-choice
- prompt "Select method for measuring the packet size s"
- default IP_DCCP_CCID3_MEASURE_S_AS_MPS
-
-config IP_DCCP_CCID3_MEASURE_S_AS_MPS
- bool "Always use MPS in place of s"
- ---help---
- This use is recommended as it is consistent with the initialisation
- of X and suggested when s varies (rfc3448bis, (1) in section 4.1).
-config IP_DCCP_CCID3_MEASURE_S_AS_AVG
- bool "Use moving average"
- ---help---
- An alternative way of tracking s, also supported by rfc3448bis.
- This used to be the default for CCID-3 in previous kernels.
-config IP_DCCP_CCID3_MEASURE_S_AS_MAX
- bool "Track the maximum payload length"
- ---help---
- An experimental method based on tracking the maximum packet size.
-endchoice
-
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.
@@ -123,7 +106,6 @@ config IP_DCCP_CCID3_RTO
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.
-endif # IP_DCCP_CCID3
config IP_DCCP_TFRC_LIB
tristate
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index fa713227c66f..9a430734530c 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -25,7 +25,7 @@
/*
* This implementation should follow RFC 4341
*/
-#include "../feat.h"
+
#include "../ccid.h"
#include "../dccp.h"
#include "ccid2.h"
@@ -34,8 +34,51 @@
#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 *hctx)
+{
+ int len = 0;
+ int pipe = 0;
+ struct ccid2_seq *seqp = hctx->ccid2hctx_seqh;
+
+ /* there is data in the chain */
+ if (seqp != hctx->ccid2hctx_seqt) {
+ seqp = seqp->ccid2s_prev;
+ len++;
+ if (!seqp->ccid2s_acked)
+ pipe++;
+
+ while (seqp != hctx->ccid2hctx_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 != hctx->ccid2hctx_pipe);
+ ccid2_pr_debug("len of chain=%d\n", len);
+
+ do {
+ seqp = seqp->ccid2s_prev;
+ len++;
+ } while (seqp != hctx->ccid2hctx_seqh);
+
+ ccid2_pr_debug("total len=%d\n", len);
+ BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN);
+}
#else
#define ccid2_pr_debug(format, a...)
+#define ccid2_hc_tx_check_sanity(hctx)
#endif
static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx)
@@ -44,7 +87,8 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx)
int i;
/* check if we have space to preserve the pointer to the buffer */
- if (hctx->seqbufc >= sizeof(hctx->seqbuf) / sizeof(struct ccid2_seq *))
+ if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) /
+ sizeof(struct ccid2_seq*)))
return -ENOMEM;
/* allocate buffer and initialize linked list */
@@ -60,35 +104,38 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx)
seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
/* This is the first allocation. Initiate the head and tail. */
- if (hctx->seqbufc == 0)
- hctx->seqh = hctx->seqt = seqp;
+ if (hctx->ccid2hctx_seqbufc == 0)
+ hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp;
else {
/* link the existing list with the one we just created */
- hctx->seqh->ccid2s_next = seqp;
- seqp->ccid2s_prev = hctx->seqh;
+ hctx->ccid2hctx_seqh->ccid2s_next = seqp;
+ seqp->ccid2s_prev = hctx->ccid2hctx_seqh;
- hctx->seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
- seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->seqt;
+ hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
+ seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt;
}
/* store the original pointer to the buffer so we can free it */
- hctx->seqbuf[hctx->seqbufc] = seqp;
- hctx->seqbufc++;
+ hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp;
+ hctx->ccid2hctx_seqbufc++;
return 0;
}
static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
{
- if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk)))
- return CCID_PACKET_WILL_DEQUEUE_LATER;
- return CCID_PACKET_SEND_AT_ONCE;
+ struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+ if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd)
+ return 0;
+
+ return 1; /* XXX CCID should dequeue when ready instead of polling */
}
static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
{
struct dccp_sock *dp = dccp_sk(sk);
- u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->cwnd, 2);
+ u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->ccid2hctx_cwnd, 2);
/*
* Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from
@@ -100,8 +147,8 @@ static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
val = max_ratio;
}
- if (val > DCCPF_ACK_RATIO_MAX)
- val = DCCPF_ACK_RATIO_MAX;
+ if (val > 0xFFFF) /* RFC 4340, 11.3 */
+ val = 0xFFFF;
if (val == dp->dccps_l_ack_ratio)
return;
@@ -110,77 +157,99 @@ 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 *hctx, long val)
+{
+ ccid2_pr_debug("change SRTT to %ld\n", val);
+ hctx->ccid2hctx_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 *hctx = ccid2_hc_tx_sk(sk);
- const bool sender_was_blocked = ccid2_cwnd_network_limited(hctx);
+ long s;
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) {
- sk_reset_timer(sk, &hctx->rtotimer, jiffies + HZ / 5);
+ sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
+ jiffies + HZ / 5);
goto out;
}
ccid2_pr_debug("RTO_EXPIRE\n");
+ ccid2_hc_tx_check_sanity(hctx);
+
/* back-off timer */
- hctx->rto <<= 1;
- if (hctx->rto > DCCP_RTO_MAX)
- hctx->rto = DCCP_RTO_MAX;
+ hctx->ccid2hctx_rto <<= 1;
+
+ s = hctx->ccid2hctx_rto / HZ;
+ if (s > 60)
+ hctx->ccid2hctx_rto = 60 * HZ;
+
+ ccid2_start_rto_timer(sk);
/* adjust pipe, cwnd etc */
- hctx->ssthresh = hctx->cwnd / 2;
- if (hctx->ssthresh < 2)
- hctx->ssthresh = 2;
- hctx->cwnd = 1;
- hctx->pipe = 0;
+ hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd / 2;
+ if (hctx->ccid2hctx_ssthresh < 2)
+ hctx->ccid2hctx_ssthresh = 2;
+ hctx->ccid2hctx_cwnd = 1;
+ hctx->ccid2hctx_pipe = 0;
/* clear state about stuff we sent */
- hctx->seqt = hctx->seqh;
- hctx->packets_acked = 0;
+ hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
+ hctx->ccid2hctx_packets_acked = 0;
/* clear ack ratio state. */
- hctx->rpseq = 0;
- hctx->rpdupack = -1;
+ hctx->ccid2hctx_rpseq = 0;
+ hctx->ccid2hctx_rpdupack = -1;
ccid2_change_l_ack_ratio(sk, 1);
-
- /* if we were blocked before, we may now send cwnd=1 packet */
- if (sender_was_blocked)
- tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
- /* restart backed-off timer */
- sk_reset_timer(sk, &hctx->rtotimer, jiffies + hctx->rto);
+ ccid2_hc_tx_check_sanity(hctx);
out:
bh_unlock_sock(sk);
sock_put(sk);
}
-static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
+static void ccid2_start_rto_timer(struct sock *sk)
+{
+ struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+ ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
+
+ BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
+ sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
+ jiffies + hctx->ccid2hctx_rto);
+}
+
+static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
struct ccid2_seq *next;
- hctx->pipe++;
+ hctx->ccid2hctx_pipe++;
- hctx->seqh->ccid2s_seq = dp->dccps_gss;
- hctx->seqh->ccid2s_acked = 0;
- hctx->seqh->ccid2s_sent = jiffies;
+ hctx->ccid2hctx_seqh->ccid2s_seq = dp->dccps_gss;
+ hctx->ccid2hctx_seqh->ccid2s_acked = 0;
+ hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
- next = hctx->seqh->ccid2s_next;
+ next = hctx->ccid2hctx_seqh->ccid2s_next;
/* check if we need to alloc more space */
- if (next == hctx->seqt) {
+ if (next == hctx->ccid2hctx_seqt) {
if (ccid2_hc_tx_alloc_seq(hctx)) {
DCCP_CRIT("packet history - out of memory!");
/* FIXME: find a more graceful way to bail out */
return;
}
- next = hctx->seqh->ccid2s_next;
- BUG_ON(next == hctx->seqt);
+ next = hctx->ccid2hctx_seqh->ccid2s_next;
+ BUG_ON(next == hctx->ccid2hctx_seqt);
}
- hctx->seqh = next;
+ hctx->ccid2hctx_seqh = next;
- ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->cwnd, hctx->pipe);
+ ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
+ hctx->ccid2hctx_pipe);
/*
* FIXME: The code below is broken and the variables have been removed
@@ -203,12 +272,12 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
*/
#if 0
/* Ack Ratio. Need to maintain a concept of how many windows we sent */
- hctx->arsent++;
+ hctx->ccid2hctx_arsent++;
/* We had an ack loss in this window... */
- if (hctx->ackloss) {
- if (hctx->arsent >= hctx->cwnd) {
- hctx->arsent = 0;
- hctx->ackloss = 0;
+ if (hctx->ccid2hctx_ackloss) {
+ if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
+ hctx->ccid2hctx_arsent = 0;
+ hctx->ccid2hctx_ackloss = 0;
}
} else {
/* No acks lost up to now... */
@@ -218,28 +287,28 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
dp->dccps_l_ack_ratio;
- denom = hctx->cwnd * hctx->cwnd / denom;
+ denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
- if (hctx->arsent >= denom) {
+ if (hctx->ccid2hctx_arsent >= denom) {
ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
- hctx->arsent = 0;
+ hctx->ccid2hctx_arsent = 0;
}
} else {
/* we can't increase ack ratio further [1] */
- hctx->arsent = 0; /* or maybe set it to cwnd*/
+ hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
}
}
#endif
/* setup RTO timer */
- if (!timer_pending(&hctx->rtotimer))
- sk_reset_timer(sk, &hctx->rtotimer, jiffies + hctx->rto);
+ if (!timer_pending(&hctx->ccid2hctx_rtotimer))
+ ccid2_start_rto_timer(sk);
#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
do {
- struct ccid2_seq *seqp = hctx->seqt;
+ struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
- while (seqp != hctx->seqh) {
+ while (seqp != hctx->ccid2hctx_seqh) {
ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
(unsigned long long)seqp->ccid2s_seq,
seqp->ccid2s_acked, seqp->ccid2s_sent);
@@ -247,158 +316,205 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
}
} while (0);
ccid2_pr_debug("=========\n");
+ ccid2_hc_tx_check_sanity(hctx);
#endif
}
-/**
- * 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].
+/* XXX Lame code duplication!
+ * returns -1 if none was found.
+ * else returns the next offset to use in the function call.
*/
-static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
+static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
+ unsigned char **vec, unsigned char *veclen)
{
- struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
- long m = mrtt ? : 1;
-
- if (hctx->srtt == 0) {
- /* First measurement m */
- hctx->srtt = m << 3;
- hctx->mdev = m << 1;
-
- hctx->mdev_max = max(TCP_RTO_MIN, hctx->mdev);
- hctx->rttvar = hctx->mdev_max;
- hctx->rtt_seq = dccp_sk(sk)->dccps_gss;
- } else {
- /* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */
- m -= (hctx->srtt >> 3);
- hctx->srtt += m;
-
- /* Similarly, update scaled mdev with regard to |m| */
- if (m < 0) {
- m = -m;
- m -= (hctx->mdev >> 2);
+ const struct dccp_hdr *dh = dccp_hdr(skb);
+ unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
+ unsigned char *opt_ptr;
+ const unsigned char *opt_end = (unsigned char *)dh +
+ (dh->dccph_doff * 4);
+ unsigned char opt, len;
+ unsigned char *value;
+
+ BUG_ON(offset < 0);
+ options += offset;
+ opt_ptr = options;
+ if (opt_ptr >= opt_end)
+ return -1;
+
+ while (opt_ptr != opt_end) {
+ opt = *opt_ptr++;
+ len = 0;
+ value = NULL;
+
+ /* Check if this isn't a single byte option */
+ if (opt > DCCPO_MAX_RESERVED) {
+ if (opt_ptr == opt_end)
+ goto out_invalid_option;
+
+ len = *opt_ptr++;
+ if (len < 3)
+ goto out_invalid_option;
/*
- * This neutralises RTO increase when RTT < SRTT - mdev
- * (see P. Sarolahti, A. Kuznetsov,"Congestion Control
- * in Linux TCP", USENIX 2002, pp. 49-62).
+ * Remove the type and len fields, leaving
+ * just the value size
*/
- if (m > 0)
- m >>= 3;
- } else {
- m -= (hctx->mdev >> 2);
- }
- hctx->mdev += m;
+ len -= 2;
+ value = opt_ptr;
+ opt_ptr += len;
- if (hctx->mdev > hctx->mdev_max) {
- hctx->mdev_max = hctx->mdev;
- if (hctx->mdev_max > hctx->rttvar)
- hctx->rttvar = hctx->mdev_max;
+ if (opt_ptr > opt_end)
+ goto out_invalid_option;
}
- /*
- * 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 as it over-estimates pipe.
- */
- if (after48(dccp_sk(sk)->dccps_gar, hctx->rtt_seq)) {
- if (hctx->mdev_max < hctx->rttvar)
- hctx->rttvar -= (hctx->rttvar -
- hctx->mdev_max) >> 2;
- hctx->rtt_seq = dccp_sk(sk)->dccps_gss;
- hctx->mdev_max = TCP_RTO_MIN;
+ switch (opt) {
+ case DCCPO_ACK_VECTOR_0:
+ case DCCPO_ACK_VECTOR_1:
+ *vec = value;
+ *veclen = len;
+ return offset + (opt_ptr - options);
}
}
- /*
- * Set RTO from SRTT and RTTVAR
- * Clock granularity is ignored since the minimum error for RTTVAR is
- * clamped to 50msec (corresponding to HZ=20). This leads to a minimum
- * RTO of 200msec. This agrees with TCP and RFC 4341, 5.: "Because DCCP
- * does not retransmit data, DCCP does not require TCP's recommended
- * minimum timeout of one second".
- */
- hctx->rto = (hctx->srtt >> 3) + hctx->rttvar;
+ return -1;
- if (hctx->rto > DCCP_RTO_MAX)
- hctx->rto = DCCP_RTO_MAX;
+out_invalid_option:
+ DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
+ return -1;
}
-static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp,
- unsigned int *maxincr)
+static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
- if (hctx->cwnd < hctx->ssthresh) {
- if (*maxincr > 0 && ++hctx->packets_acked == 2) {
- hctx->cwnd += 1;
- *maxincr -= 1;
- hctx->packets_acked = 0;
- }
- } else if (++hctx->packets_acked >= hctx->cwnd) {
- hctx->cwnd += 1;
- hctx->packets_acked = 0;
- }
- /*
- * 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 - need to be resolved at some time.
- */
- ccid2_rtt_estimator(sk, jiffies - seqp->ccid2s_sent);
+ sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
+ ccid2_pr_debug("deleted RTO timer\n");
}
-static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
+static inline void ccid2_new_ack(struct sock *sk,
+ struct ccid2_seq *seqp,
+ unsigned int *maxincr)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
- if (time_before(seqp->ccid2s_sent, hctx->last_cong)) {
- ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
- return;
+ if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
+ if (*maxincr > 0 && ++hctx->ccid2hctx_packets_acked == 2) {
+ hctx->ccid2hctx_cwnd += 1;
+ *maxincr -= 1;
+ hctx->ccid2hctx_packets_acked = 0;
+ }
+ } else if (++hctx->ccid2hctx_packets_acked >= hctx->ccid2hctx_cwnd) {
+ hctx->ccid2hctx_cwnd += 1;
+ hctx->ccid2hctx_packets_acked = 0;
}
- hctx->last_cong = jiffies;
+ /* update RTO */
+ if (hctx->ccid2hctx_srtt == -1 ||
+ time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
+ unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
+ int s;
+
+ /* first measurement */
+ if (hctx->ccid2hctx_srtt == -1) {
+ ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
+ r, jiffies,
+ (unsigned long long)seqp->ccid2s_seq);
+ ccid2_change_srtt(hctx, r);
+ hctx->ccid2hctx_rttvar = r >> 1;
+ } else {
+ /* RTTVAR */
+ long tmp = hctx->ccid2hctx_srtt - r;
+ long srtt;
+
+ if (tmp < 0)
+ tmp *= -1;
+
+ tmp >>= 2;
+ hctx->ccid2hctx_rttvar *= 3;
+ hctx->ccid2hctx_rttvar >>= 2;
+ hctx->ccid2hctx_rttvar += tmp;
+
+ /* SRTT */
+ srtt = hctx->ccid2hctx_srtt;
+ srtt *= 7;
+ srtt >>= 3;
+ tmp = r >> 3;
+ srtt += tmp;
+ ccid2_change_srtt(hctx, srtt);
+ }
+ s = hctx->ccid2hctx_rttvar << 2;
+ /* clock granularity is 1 when based on jiffies */
+ if (!s)
+ s = 1;
+ hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
+
+ /* must be at least a second */
+ s = hctx->ccid2hctx_rto / HZ;
+ /* DCCP doesn't require this [but I like it cuz my code sux] */
+#if 1
+ if (s < 1)
+ hctx->ccid2hctx_rto = HZ;
+#endif
+ /* max 60 seconds */
+ if (s > 60)
+ hctx->ccid2hctx_rto = HZ * 60;
- hctx->cwnd = hctx->cwnd / 2 ? : 1U;
- hctx->ssthresh = max(hctx->cwnd, 2U);
+ hctx->ccid2hctx_lastrtt = jiffies;
- /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */
- if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->cwnd)
- ccid2_change_l_ack_ratio(sk, hctx->cwnd);
+ ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
+ hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
+ hctx->ccid2hctx_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 int ccid2_hc_tx_parse_options(struct sock *sk, u8 packet_type,
- u8 option, u8 *optval, u8 optlen)
+static void ccid2_hc_tx_dec_pipe(struct sock *sk)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
- switch (option) {
- case DCCPO_ACK_VECTOR_0:
- case DCCPO_ACK_VECTOR_1:
- return dccp_ackvec_parsed_add(&hctx->av_chunks, optval, optlen,
- option - DCCPO_ACK_VECTOR_0);
+ if (hctx->ccid2hctx_pipe == 0)
+ DCCP_BUG("pipe == 0");
+ else
+ hctx->ccid2hctx_pipe--;
+
+ if (hctx->ccid2hctx_pipe == 0)
+ ccid2_hc_tx_kill_rto_timer(sk);
+}
+
+static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
+{
+ struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+ if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
+ ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
+ return;
}
- return 0;
+
+ hctx->ccid2hctx_last_cong = jiffies;
+
+ hctx->ccid2hctx_cwnd = hctx->ccid2hctx_cwnd / 2 ? : 1U;
+ hctx->ccid2hctx_ssthresh = max(hctx->ccid2hctx_cwnd, 2U);
+
+ /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */
+ if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->ccid2hctx_cwnd)
+ ccid2_change_l_ack_ratio(sk, hctx->ccid2hctx_cwnd);
}
static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
- const bool sender_was_blocked = ccid2_cwnd_network_limited(hctx);
- struct dccp_ackvec_parsed *avp;
u64 ackno, seqno;
struct ccid2_seq *seqp;
+ unsigned char *vector;
+ unsigned char veclen;
+ int offset = 0;
int done = 0;
unsigned int maxincr = 0;
+ ccid2_hc_tx_check_sanity(hctx);
/* check reverse path congestion */
seqno = DCCP_SKB_CB(skb)->dccpd_seq;
@@ -407,21 +523,21 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
* -sorbo.
*/
/* need to bootstrap */
- if (hctx->rpdupack == -1) {
- hctx->rpdupack = 0;
- hctx->rpseq = seqno;
+ if (hctx->ccid2hctx_rpdupack == -1) {
+ hctx->ccid2hctx_rpdupack = 0;
+ hctx->ccid2hctx_rpseq = seqno;
} else {
/* check if packet is consecutive */
- if (dccp_delta_seqno(hctx->rpseq, seqno) == 1)
- hctx->rpseq = seqno;
+ if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1)
+ hctx->ccid2hctx_rpseq = seqno;
/* it's a later packet */
- else if (after48(seqno, hctx->rpseq)) {
- hctx->rpdupack++;
+ else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
+ hctx->ccid2hctx_rpdupack++;
/* check if we got enough dupacks */
- if (hctx->rpdupack >= NUMDUPACK) {
- hctx->rpdupack = -1; /* XXX lame */
- hctx->rpseq = 0;
+ if (hctx->ccid2hctx_rpdupack >= NUMDUPACK) {
+ hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
+ hctx->ccid2hctx_rpseq = 0;
ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio);
}
@@ -429,22 +545,27 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
}
/* check forward path congestion */
- if (dccp_packet_without_ack(skb))
+ /* still didn't send out new data packets */
+ if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
return;
- /* still didn't send out new data packets */
- if (hctx->seqh == hctx->seqt)
- goto done;
+ switch (DCCP_SKB_CB(skb)->dccpd_type) {
+ case DCCP_PKT_ACK:
+ case DCCP_PKT_DATAACK:
+ break;
+ default:
+ return;
+ }
ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
- if (after48(ackno, hctx->high_ack))
- hctx->high_ack = ackno;
+ if (after48(ackno, hctx->ccid2hctx_high_ack))
+ hctx->ccid2hctx_high_ack = ackno;
- seqp = hctx->seqt;
+ seqp = hctx->ccid2hctx_seqt;
while (before48(seqp->ccid2s_seq, ackno)) {
seqp = seqp->ccid2s_next;
- if (seqp == hctx->seqh) {
- seqp = hctx->seqh->ccid2s_prev;
+ if (seqp == hctx->ccid2hctx_seqh) {
+ seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
break;
}
}
@@ -454,26 +575,26 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
* packets per acknowledgement. Rounding up avoids that cwnd is not
* advanced when Ack Ratio is 1 and gives a slight edge otherwise.
*/
- if (hctx->cwnd < hctx->ssthresh)
+ if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh)
maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2);
/* go through all ack vectors */
- list_for_each_entry(avp, &hctx->av_chunks, node) {
+ while ((offset = ccid2_ackvector(sk, skb, offset,
+ &vector, &veclen)) != -1) {
/* go through this ack vector */
- for (; avp->len--; avp->vec++) {
- u64 ackno_end_rl = SUB48(ackno,
- dccp_ackvec_runlen(avp->vec));
+ while (veclen--) {
+ const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
+ u64 ackno_end_rl = SUB48(ackno, rl);
- ccid2_pr_debug("ackvec %llu |%u,%u|\n",
+ ccid2_pr_debug("ackvec start:%llu end:%llu\n",
(unsigned long long)ackno,
- dccp_ackvec_state(avp->vec) >> 6,
- dccp_ackvec_runlen(avp->vec));
+ (unsigned long long)ackno_end_rl);
/* if the seqno we are analyzing is larger than the
* current ackno, then move towards the tail of our
* seqnos.
*/
while (after48(seqp->ccid2s_seq, ackno)) {
- if (seqp == hctx->seqt) {
+ if (seqp == hctx->ccid2hctx_seqt) {
done = 1;
break;
}
@@ -486,24 +607,26 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
* run length
*/
while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
- const u8 state = dccp_ackvec_state(avp->vec);
+ const u8 state = *vector &
+ DCCP_ACKVEC_STATE_MASK;
/* new packet received or marked */
- if (state != DCCPAV_NOT_RECEIVED &&
+ if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
!seqp->ccid2s_acked) {
- if (state == DCCPAV_ECN_MARKED)
+ if (state ==
+ DCCP_ACKVEC_STATE_ECN_MARKED) {
ccid2_congestion_event(sk,
seqp);
- else
+ } else
ccid2_new_ack(sk, seqp,
&maxincr);
seqp->ccid2s_acked = 1;
ccid2_pr_debug("Got ack for %llu\n",
(unsigned long long)seqp->ccid2s_seq);
- hctx->pipe--;
+ ccid2_hc_tx_dec_pipe(sk);
}
- if (seqp == hctx->seqt) {
+ if (seqp == hctx->ccid2hctx_seqt) {
done = 1;
break;
}
@@ -513,6 +636,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
break;
ackno = SUB48(ackno_end_rl, 1);
+ vector++;
}
if (done)
break;
@@ -521,11 +645,11 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
/* The state about what is acked should be correct now
* Check for NUMDUPACK
*/
- seqp = hctx->seqt;
- while (before48(seqp->ccid2s_seq, hctx->high_ack)) {
+ seqp = hctx->ccid2hctx_seqt;
+ while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
seqp = seqp->ccid2s_next;
- if (seqp == hctx->seqh) {
- seqp = hctx->seqh->ccid2s_prev;
+ if (seqp == hctx->ccid2hctx_seqh) {
+ seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
break;
}
}
@@ -536,7 +660,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
if (done == NUMDUPACK)
break;
}
- if (seqp == hctx->seqt)
+ if (seqp == hctx->ccid2hctx_seqt)
break;
seqp = seqp->ccid2s_prev;
}
@@ -557,34 +681,25 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
* one ack vector.
*/
ccid2_congestion_event(sk, seqp);
- hctx->pipe--;
+ ccid2_hc_tx_dec_pipe(sk);
}
- if (seqp == hctx->seqt)
+ if (seqp == hctx->ccid2hctx_seqt)
break;
seqp = seqp->ccid2s_prev;
}
- hctx->seqt = last_acked;
+ hctx->ccid2hctx_seqt = last_acked;
}
/* trim acked packets in tail */
- while (hctx->seqt != hctx->seqh) {
- if (!hctx->seqt->ccid2s_acked)
+ while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
+ if (!hctx->ccid2hctx_seqt->ccid2s_acked)
break;
- hctx->seqt = hctx->seqt->ccid2s_next;
+ hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
}
- /* restart RTO timer if not all outstanding data has been acked */
- if (hctx->pipe == 0)
- sk_stop_timer(sk, &hctx->rtotimer);
- else
- sk_reset_timer(sk, &hctx->rtotimer, jiffies + hctx->rto);
-done:
- /* check if incoming Acks allow pending packets to be sent */
- if (sender_was_blocked && !ccid2_cwnd_network_limited(hctx))
- tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
- dccp_ackvec_parsed_cleanup(&hctx->av_chunks);
+ ccid2_hc_tx_check_sanity(hctx);
}
static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -594,13 +709,17 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
u32 max_ratio;
/* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */
- hctx->ssthresh = ~0U;
+ hctx->ccid2hctx_ssthresh = ~0U;
- /* Use larger initial windows (RFC 3390, rfc2581bis) */
- hctx->cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache);
+ /*
+ * 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.
+ */
+ hctx->ccid2hctx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U);
/* Make sure that Ack Ratio is enabled and within bounds. */
- max_ratio = DIV_ROUND_UP(hctx->cwnd, 2);
+ max_ratio = DIV_ROUND_UP(hctx->ccid2hctx_cwnd, 2);
if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio)
dp->dccps_l_ack_ratio = max_ratio;
@@ -608,11 +727,15 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
if (ccid2_hc_tx_alloc_seq(hctx))
return -ENOMEM;
- hctx->rto = DCCP_TIMEOUT_INIT;
- hctx->rpdupack = -1;
- hctx->last_cong = jiffies;
- setup_timer(&hctx->rtotimer, ccid2_hc_tx_rto_expire, (unsigned long)sk);
- INIT_LIST_HEAD(&hctx->av_chunks);
+ hctx->ccid2hctx_rto = 3 * HZ;
+ ccid2_change_srtt(hctx, -1);
+ hctx->ccid2hctx_rttvar = -1;
+ hctx->ccid2hctx_rpdupack = -1;
+ hctx->ccid2hctx_last_cong = jiffies;
+ setup_timer(&hctx->ccid2hctx_rtotimer, ccid2_hc_tx_rto_expire,
+ (unsigned long)sk);
+
+ ccid2_hc_tx_check_sanity(hctx);
return 0;
}
@@ -621,11 +744,11 @@ static void ccid2_hc_tx_exit(struct sock *sk)
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
int i;
- sk_stop_timer(sk, &hctx->rtotimer);
+ ccid2_hc_tx_kill_rto_timer(sk);
- for (i = 0; i < hctx->seqbufc; i++)
- kfree(hctx->seqbuf[i]);
- hctx->seqbufc = 0;
+ for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
+ kfree(hctx->ccid2hctx_seqbuf[i]);
+ hctx->ccid2hctx_seqbufc = 0;
}
static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
@@ -636,28 +759,27 @@ static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
switch (DCCP_SKB_CB(skb)->dccpd_type) {
case DCCP_PKT_DATA:
case DCCP_PKT_DATAACK:
- hcrx->data++;
- if (hcrx->data >= dp->dccps_r_ack_ratio) {
+ hcrx->ccid2hcrx_data++;
+ if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
dccp_send_ack(sk);
- hcrx->data = 0;
+ hcrx->ccid2hcrx_data = 0;
}
break;
}
}
static struct ccid_operations ccid2 = {
- .ccid_id = DCCPC_CCID2,
- .ccid_name = "TCP-like",
- .ccid_owner = THIS_MODULE,
- .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
- .ccid_hc_tx_init = ccid2_hc_tx_init,
- .ccid_hc_tx_exit = ccid2_hc_tx_exit,
- .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
- .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
- .ccid_hc_tx_parse_options = ccid2_hc_tx_parse_options,
- .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
- .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
- .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
+ .ccid_id = DCCPC_CCID2,
+ .ccid_name = "TCP-like",
+ .ccid_owner = THIS_MODULE,
+ .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
+ .ccid_hc_tx_init = ccid2_hc_tx_init,
+ .ccid_hc_tx_exit = ccid2_hc_tx_exit,
+ .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
+ .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
+ .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
+ .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
+ .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
};
#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
index 8b7a2dee2f6d..2c94ca029010 100644
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
@@ -42,49 +42,34 @@ struct ccid2_seq {
/** struct ccid2_hc_tx_sock - CCID2 TX half connection
*
- * @{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
- * @packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
- * @srtt: smoothed RTT estimate, scaled by 2^3
- * @mdev: smoothed RTT variation, scaled by 2^2
- * @mdev_max: maximum of @mdev during one flight
- * @rttvar: moving average/maximum of @mdev_max
- * @rto: RTO value deriving from SRTT and RTTVAR (RFC 2988)
- * @rtt_seq: to decay RTTVAR at most once per flight
- * @rpseq: last consecutive seqno
- * @rpdupack: dupacks since rpseq
- * @av_chunks: list of Ack Vectors received on current skb
- */
+ * @ccid2hctx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
+ * @ccid2hctx_packets_acked - Ack counter for deriving cwnd growth (RFC 3465)
+ * @ccid2hctx_lastrtt -time RTT was last measured
+ * @ccid2hctx_rpseq - last consecutive seqno
+ * @ccid2hctx_rpdupack - dupacks since rpseq
+*/
struct ccid2_hc_tx_sock {
- u32 cwnd;
- u32 ssthresh;
- u32 pipe;
- u32 packets_acked;
- struct ccid2_seq *seqbuf[CCID2_SEQBUF_MAX];
- int seqbufc;
- struct ccid2_seq *seqh;
- struct ccid2_seq *seqt;
- /* RTT measurement: variables/principles are the same as in TCP */
- u32 srtt,
- mdev,
- mdev_max,
- rttvar,
- rto;
- u64 rtt_seq:48;
- struct timer_list rtotimer;
- u64 rpseq;
- int rpdupack;
- unsigned long last_cong;
- u64 high_ack;
- struct list_head av_chunks;
+ u32 ccid2hctx_cwnd;
+ u32 ccid2hctx_ssthresh;
+ u32 ccid2hctx_pipe;
+ u32 ccid2hctx_packets_acked;
+ struct ccid2_seq *ccid2hctx_seqbuf[CCID2_SEQBUF_MAX];
+ int ccid2hctx_seqbufc;
+ struct ccid2_seq *ccid2hctx_seqh;
+ struct ccid2_seq *ccid2hctx_seqt;
+ long ccid2hctx_rto;
+ long ccid2hctx_srtt;
+ long ccid2hctx_rttvar;
+ unsigned long ccid2hctx_lastrtt;
+ struct timer_list ccid2hctx_rtotimer;
+ u64 ccid2hctx_rpseq;
+ int ccid2hctx_rpdupack;
+ unsigned long ccid2hctx_last_cong;
+ u64 ccid2hctx_high_ack;
};
-static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hctx)
-{
- return (hctx->pipe >= hctx->cwnd);
-}
-
struct ccid2_hc_rx_sock {
- int data;
+ int ccid2hcrx_data;
};
static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 06cfdad84a6a..3b8bd7ca6761 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -49,41 +49,75 @@ static int ccid3_debug;
/*
* Transmitter Half-Connection Routines
*/
-/* Oscillation Prevention/Reduction: recommended by rfc3448bis, on by default */
-static int do_osc_prev = true;
+#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
+static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
+{
+ static char *ccid3_state_names[] = {
+ [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];
+}
+#endif
+
+static void ccid3_hc_tx_set_state(struct sock *sk,
+ enum ccid3_hc_tx_states state)
+{
+ struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+ enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
+
+ ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
+ dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
+ ccid3_tx_state_name(state));
+ WARN_ON(state == oldstate);
+ hctx->ccid3hctx_state = state;
+}
/*
* Compute the initial sending rate X_init in the manner of RFC 3390:
*
- * X_init = min(4 * MPS, max(2 * MPS, 4380 bytes)) / RTT
+ * 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 u32 mps = dccp_sk(sk)->dccps_mss_cache,
- w_init = clamp(4380U, 2 * mps, 4 * mps);
+ const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+ const __u32 w_init = clamp_t(__u32, 4380U,
+ 2 * hctx->ccid3hctx_s, 4 * hctx->ccid3hctx_s);
- return scaled_div(w_init << 6, ccid3_hc_tx_sk(sk)->rtt);
+ return scaled_div(w_init << 6, hctx->ccid3hctx_rtt);
}
-/**
- * ccid3_update_send_interval - Calculate new t_ipi = s / X
- * This respects the granularity of X (64 * bytes/second) and enforces the
- * scaled minimum of s * 64 / t_mbi = `s' bytes/second as per RFC 3448/4342.
+/*
+ * Recalculate t_ipi and delta (should be called whenever X changes)
*/
static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
{
- if (unlikely(hctx->x <= hctx->s))
- hctx->x = hctx->s;
- hctx->t_ipi = scaled_div32(((u64)hctx->s) << 6, hctx->x);
+ /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
+ hctx->ccid3hctx_t_ipi = scaled_div32(((u64)hctx->ccid3hctx_s) << 6,
+ hctx->ccid3hctx_x);
+
+ /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
+ hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
+ TFRC_OPSYS_HALF_TIME_GRAN);
+
+ ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n",
+ hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta,
+ hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_x >> 6));
+
}
static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now)
{
- u32 delta = ktime_us_delta(now, hctx->t_last_win_count);
+ u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
- return delta / hctx->rtt;
+ return delta / hctx->ccid3hctx_rtt;
}
/**
@@ -99,8 +133,8 @@ static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now)
static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
- u64 min_rate = 2 * hctx->x_recv;
- const u64 old_x = hctx->x;
+ __u64 min_rate = 2 * hctx->ccid3hctx_x_recv;
+ const __u64 old_x = hctx->ccid3hctx_x;
ktime_t now = stamp ? *stamp : ktime_get_real();
/*
@@ -111,44 +145,50 @@ static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
*/
if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) {
min_rate = rfc3390_initial_rate(sk);
- min_rate = max(min_rate, 2 * hctx->x_recv);
+ min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
}
- if (hctx->p > 0) {
+ if (hctx->ccid3hctx_p > 0) {
- hctx->x = min(((u64)hctx->x_calc) << 6, min_rate);
+ hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
+ min_rate);
+ hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
+ (((__u64)hctx->ccid3hctx_s) << 6) /
+ TFRC_T_MBI);
- } else if (ktime_us_delta(now, hctx->t_ld) - (s64)hctx->rtt >= 0) {
+ } else if (ktime_us_delta(now, hctx->ccid3hctx_t_ld)
+ - (s64)hctx->ccid3hctx_rtt >= 0) {
- hctx->x = min(2 * hctx->x, min_rate);
- hctx->x = max(hctx->x,
- scaled_div(((u64)hctx->s) << 6, hctx->rtt));
- hctx->t_ld = now;
+ hctx->ccid3hctx_x = min(2 * hctx->ccid3hctx_x, min_rate);
+ hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
+ scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
+ hctx->ccid3hctx_rtt));
+ hctx->ccid3hctx_t_ld = now;
}
- if (hctx->x != old_x) {
+ if (hctx->ccid3hctx_x != old_x) {
ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
"X_recv=%u\n", (unsigned)(old_x >> 6),
- (unsigned)(hctx->x >> 6), hctx->x_calc,
- (unsigned)(hctx->x_recv >> 6));
+ (unsigned)(hctx->ccid3hctx_x >> 6),
+ hctx->ccid3hctx_x_calc,
+ (unsigned)(hctx->ccid3hctx_x_recv >> 6));
ccid3_update_send_interval(hctx);
}
}
/*
- * ccid3_hc_tx_measure_packet_size - Measuring the packet size `s' (sec 4.1)
- * @new_len: DCCP payload size in bytes (not used by all methods)
+ * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
+ * @len: DCCP packet payload size in bytes
*/
-static u32 ccid3_hc_tx_measure_packet_size(struct sock *sk, const u16 new_len)
+static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
{
-#if defined(CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_AVG)
- return tfrc_ewma(ccid3_hc_tx_sk(sk)->s, new_len, 9);
-#elif defined(CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_MAX)
- return max(ccid3_hc_tx_sk(sk)->s, new_len);
-#else /* CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_MPS */
- return dccp_sk(sk)->dccps_mss_cache;
-#endif
+ const u16 old_s = hctx->ccid3hctx_s;
+
+ hctx->ccid3hctx_s = tfrc_ewma(hctx->ccid3hctx_s, len, 9);
+
+ if (hctx->ccid3hctx_s != old_s)
+ ccid3_update_send_interval(hctx);
}
/*
@@ -158,13 +198,13 @@ static u32 ccid3_hc_tx_measure_packet_size(struct sock *sk, const u16 new_len)
static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
ktime_t now)
{
- u32 delta = ktime_us_delta(now, hctx->t_last_win_count),
- quarter_rtts = (4 * delta) / hctx->rtt;
+ u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count),
+ quarter_rtts = (4 * delta) / hctx->ccid3hctx_rtt;
if (quarter_rtts > 0) {
- hctx->t_last_win_count = now;
- hctx->last_win_count += min(quarter_rtts, 5U);
- hctx->last_win_count &= 0xF; /* mod 16 */
+ hctx->ccid3hctx_t_last_win_count = now;
+ hctx->ccid3hctx_last_win_count += min(quarter_rtts, 5U);
+ hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
}
}
@@ -181,26 +221,25 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
goto restart_timer;
}
- ccid3_pr_debug("%s(%p) entry with%s feedback\n", dccp_role(sk), sk,
- hctx->feedback ? "" : "out");
+ ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
+ ccid3_tx_state_name(hctx->ccid3hctx_state));
- /* Ignore and do not restart after leaving the established state */
- if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
+ if (hctx->ccid3hctx_state == TFRC_SSTATE_FBACK)
+ ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
+ else if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
goto out;
- /* Reset feedback state to "no feedback received" */
- hctx->feedback = false;
-
/*
* 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 (hctx->t_rto == 0 || hctx->p == 0) {
+ if (hctx->ccid3hctx_t_rto == 0 || /* no feedback received yet */
+ hctx->ccid3hctx_p == 0) {
/* halve send rate directly */
- hctx->x /= 2;
+ hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
+ (((__u64)hctx->ccid3hctx_s) << 6) /
+ TFRC_T_MBI);
ccid3_update_send_interval(hctx);
-
} else {
/*
* Modify the cached value of X_recv
@@ -212,41 +251,44 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
*
* Note that X_recv is scaled by 2^6 while X_calc is not
*/
- BUG_ON(hctx->p && !hctx->x_calc);
+ BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
- if (hctx->x_calc > (hctx->x_recv >> 5))
- hctx->x_recv /= 2;
+ if (hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5))
+ hctx->ccid3hctx_x_recv =
+ max(hctx->ccid3hctx_x_recv / 2,
+ (((__u64)hctx->ccid3hctx_s) << 6) /
+ (2 * TFRC_T_MBI));
else {
- hctx->x_recv = hctx->x_calc;
- hctx->x_recv <<= 4;
+ hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
+ hctx->ccid3hctx_x_recv <<= 4;
}
ccid3_hc_tx_update_x(sk, NULL);
}
ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n",
- (unsigned long long)hctx->x);
+ (unsigned long long)hctx->ccid3hctx_x);
/*
* Set new timeout for the nofeedback timer.
* See comments in packet_recv() regarding the value of t_RTO.
*/
- if (unlikely(hctx->t_rto == 0)) /* no feedback received yet */
+ if (unlikely(hctx->ccid3hctx_t_rto == 0)) /* no feedback yet */
t_nfb = TFRC_INITIAL_TIMEOUT;
else
- t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi);
+ t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
restart_timer:
- sk_reset_timer(sk, &hctx->no_feedback_timer,
+ sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + usecs_to_jiffies(t_nfb));
out:
bh_unlock_sock(sk);
sock_put(sk);
}
-/**
- * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets
- * @skb: next packet candidate to send on @sk
- * This function uses the convention of ccid_packet_dequeue_eval() and
- * returns a millisecond-delay value between 0 and t_mbi = 64000 msec.
+/*
+ * returns
+ * > 0: delay (in msecs) that should pass before actually sending
+ * = 0: can send immediately
+ * < 0: error condition; do not send packet
*/
static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
{
@@ -263,14 +305,18 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
if (unlikely(skb->len == 0))
return -EBADMSG;
- if (hctx->s == 0) {
- sk_reset_timer(sk, &hctx->no_feedback_timer, (jiffies +
+ switch (hctx->ccid3hctx_state) {
+ case TFRC_SSTATE_NO_SENT:
+ sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
+ (jiffies +
usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
- hctx->last_win_count = 0;
- hctx->t_last_win_count = now;
+ hctx->ccid3hctx_last_win_count = 0;
+ hctx->ccid3hctx_t_last_win_count = now;
/* Set t_0 for initial packet */
- hctx->t_nom = now;
+ hctx->ccid3hctx_t_nom = now;
+
+ hctx->ccid3hctx_s = skb->len;
/*
* Use initial RTT sample when available: recommended by erratum
@@ -279,9 +325,9 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
*/
if (dp->dccps_syn_rtt) {
ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
- hctx->rtt = dp->dccps_syn_rtt;
- hctx->x = rfc3390_initial_rate(sk);
- hctx->t_ld = now;
+ hctx->ccid3hctx_rtt = dp->dccps_syn_rtt;
+ hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
+ hctx->ccid3hctx_t_ld = now;
} else {
/*
* Sender does not have RTT sample:
@@ -289,20 +335,17 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
* is needed in several parts (e.g. window counter);
* - set sending rate X_pps = 1pps as per RFC 3448, 4.2.
*/
- hctx->rtt = DCCP_FALLBACK_RTT;
- hctx->x = dp->dccps_mss_cache;
- hctx->x <<= 6;
+ hctx->ccid3hctx_rtt = DCCP_FALLBACK_RTT;
+ hctx->ccid3hctx_x = hctx->ccid3hctx_s;
+ hctx->ccid3hctx_x <<= 6;
}
-
- /* Compute t_ipi = s / X */
- hctx->s = ccid3_hc_tx_measure_packet_size(sk, skb->len);
ccid3_update_send_interval(hctx);
- /* Seed value for Oscillation Prevention (sec. 4.5) */
- hctx->r_sqmean = tfrc_scaled_sqrt(hctx->rtt);
-
- } else {
- delay = ktime_us_delta(hctx->t_nom, now);
+ ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
+ break;
+ case TFRC_SSTATE_NO_FBACK:
+ case TFRC_SSTATE_FBACK:
+ delay = ktime_us_delta(hctx->ccid3hctx_t_nom, now);
ccid3_pr_debug("delay=%ld\n", (long)delay);
/*
* Scheduling of packet transmissions [RFC 3448, 4.6]
@@ -312,80 +355,99 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
* else
* // send the packet in (t_nom - t_now) milliseconds.
*/
- if (delay >= TFRC_T_DELTA)
- return (u32)delay / USEC_PER_MSEC;
+ if (delay - (s64)hctx->ccid3hctx_delta >= 1000)
+ return (u32)delay / 1000L;
ccid3_hc_tx_update_win_count(hctx, 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.) */
dp->dccps_hc_tx_insert_options = 1;
- DCCP_SKB_CB(skb)->dccpd_ccval = hctx->last_win_count;
+ DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
/* set the nominal send time for the next following packet */
- hctx->t_nom = ktime_add_us(hctx->t_nom, hctx->t_ipi);
- return CCID_PACKET_SEND_AT_ONCE;
+ hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi);
+ return 0;
}
-static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
+static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
+ unsigned int len)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
- /* Changes to s will become effective the next time X is computed */
- hctx->s = ccid3_hc_tx_measure_packet_size(sk, len);
+ ccid3_hc_tx_update_s(hctx, len);
- if (tfrc_tx_hist_add(&hctx->hist, dccp_sk(sk)->dccps_gss))
+ if (tfrc_tx_hist_add(&hctx->ccid3hctx_hist, dccp_sk(sk)->dccps_gss))
DCCP_CRIT("packet history - out of memory!");
}
static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
- struct tfrc_tx_hist_entry *acked;
+ struct ccid3_options_received *opt_recv;
ktime_t now;
unsigned long t_nfb;
- u32 r_sample;
+ u32 pinv, 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;
- /*
- * 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).
- */
- acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb));
- if (acked == NULL)
+ /* ... and only in the established state */
+ if (hctx->ccid3hctx_state != TFRC_SSTATE_FBACK &&
+ hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
+ return;
+
+ opt_recv = &hctx->ccid3hctx_options_received;
+ now = ktime_get_real();
+
+ /* Estimate RTT from history if ACK number is valid */
+ r_sample = tfrc_tx_hist_rtt(hctx->ccid3hctx_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;
- /* 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));
- hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9);
+ /* Update receive rate in units of 64 * bytes/second */
+ hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
+ hctx->ccid3hctx_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 */
+ hctx->ccid3hctx_p = 0;
+ else /* can not exceed 100% */
+ hctx->ccid3hctx_p = scaled_div(1, pinv);
+ /*
+ * Validate new RTT sample and update moving average
+ */
+ r_sample = dccp_sample_rtt(sk, r_sample);
+ hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9);
/*
* Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
*/
- if (!hctx->feedback) {
- hctx->feedback = true;
+ if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
+ ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
- if (hctx->t_rto == 0) {
+ if (hctx->ccid3hctx_t_rto == 0) {
/*
* Initial feedback packet: Larger Initial Windows (4.2)
*/
- hctx->x = rfc3390_initial_rate(sk);
- hctx->t_ld = now;
+ hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
+ hctx->ccid3hctx_t_ld = now;
ccid3_update_send_interval(hctx);
goto done_computing_x;
- } else if (hctx->p == 0) {
+ } else if (hctx->ccid3hctx_p == 0) {
/*
* First feedback after nofeedback timer expiry (4.3)
*/
@@ -394,52 +456,25 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
}
/* Update sending rate (step 4 of [RFC 3448, 4.3]) */
- if (hctx->p > 0)
- hctx->x_calc = tfrc_calc_x(hctx->s, hctx->rtt, hctx->p);
+ if (hctx->ccid3hctx_p > 0)
+ hctx->ccid3hctx_x_calc =
+ tfrc_calc_x(hctx->ccid3hctx_s,
+ hctx->ccid3hctx_rtt,
+ hctx->ccid3hctx_p);
ccid3_hc_tx_update_x(sk, &now);
done_computing_x:
ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
"p=%u, X_calc=%u, X_recv=%u, X=%u\n",
- dccp_role(sk), sk, hctx->rtt, r_sample,
- hctx->s, hctx->p, hctx->x_calc,
- (unsigned)(hctx->x_recv >> 6),
- (unsigned)(hctx->x >> 6));
- /*
- * Oscillation Reduction (RFC 3448, 4.5) - modifying t_ipi according to
- * RTT changes, multiplying by X/X_inst = sqrt(R_sample)/R_sqmean. This
- * can be useful if few connections share a link, avoiding that buffer
- * fill levels (RTT) oscillate as a result of frequent adjustments to X.
- * A useful presentation with background information is in
- * Joerg Widmer, "Equation-Based Congestion Control",
- * MSc Thesis, University of Mannheim, Germany, 2000
- * (sec. 3.6.4), who calls this ISM ("Inter-packet Space Modulation").
- */
- if (do_osc_prev) {
- r_sample = tfrc_scaled_sqrt(r_sample);
- /*
- * The modulation can work in both ways: increase/decrease t_ipi
- * according to long-term increases/decreases of the RTT. The
- * former is a useful measure, since it works against queue
- * build-up. The latter temporarily increases the sending rate,
- * so that buffers fill up more quickly. This in turn causes
- * the RTT to increase, so that either later reduction becomes
- * necessary or the RTT stays at a very high level. Decreasing
- * t_ipi is therefore not supported.
- * Furthermore, during the initial slow-start phase the RTT
- * naturally increases, where using the algorithm would cause
- * delays. Hence it is disabled during the initial slow-start.
- */
- if (r_sample > hctx->r_sqmean && hctx->p > 0)
- hctx->t_ipi = div_u64((u64)hctx->t_ipi * (u64)r_sample,
- hctx->r_sqmean);
- hctx->t_ipi = min_t(u32, hctx->t_ipi, TFRC_T_MBI);
- /* update R_sqmean _after_ computing the modulation factor */
- hctx->r_sqmean = tfrc_ewma(hctx->r_sqmean, r_sample, 9);
- }
+ dccp_role(sk),
+ sk, hctx->ccid3hctx_rtt, r_sample,
+ hctx->ccid3hctx_s, hctx->ccid3hctx_p,
+ hctx->ccid3hctx_x_calc,
+ (unsigned)(hctx->ccid3hctx_x_recv >> 6),
+ (unsigned)(hctx->ccid3hctx_x >> 6));
/* unschedule no feedback timer */
- sk_stop_timer(sk, &hctx->no_feedback_timer);
+ sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
/*
* As we have calculated new ipi, delta, t_nom it is possible
@@ -453,66 +488,95 @@ done_computing_x:
* This can help avoid triggering the nofeedback timer too
* often ('spinning') on LANs with small RTTs.
*/
- hctx->t_rto = max_t(u32, 4 * hctx->rtt, (CONFIG_IP_DCCP_CCID3_RTO *
- (USEC_PER_SEC / 1000)));
+ hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
+ (CONFIG_IP_DCCP_CCID3_RTO *
+ (USEC_PER_SEC / 1000)));
/*
* Schedule no feedback timer to expire in
* max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
*/
- t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi);
+ t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
"expire in %lu jiffies (%luus)\n",
- dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb);
+ dccp_role(sk),
+ sk, usecs_to_jiffies(t_nfb), t_nfb);
- sk_reset_timer(sk, &hctx->no_feedback_timer,
+ sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + usecs_to_jiffies(t_nfb));
}
-static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
- u8 option, u8 *optval, u8 optlen)
+static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
+ unsigned char len, u16 idx,
+ unsigned char *value)
{
+ int rc = 0;
+ const struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+ struct ccid3_options_received *opt_recv;
__be32 opt_val;
- switch (option) {
- case TFRC_OPT_RECEIVE_RATE:
- case TFRC_OPT_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;
- }
- opt_val = ntohl(get_unaligned((__be32 *)optval));
+ opt_recv = &hctx->ccid3hctx_options_received;
- if (option == TFRC_OPT_RECEIVE_RATE) {
- /* Receive Rate is kept in units of 64 bytes/second */
- hctx->x_recv = opt_val;
- hctx->x_recv <<= 6;
+ 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;
+ }
- ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
- dccp_role(sk), sk, opt_val);
+ switch (option) {
+ 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 {
- /* Update the fixpoint Loss Event Rate fraction */
- hctx->p = tfrc_invert_loss_event_rate(opt_val);
-
+ 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_val);
+ dccp_role(sk), sk,
+ opt_recv->ccid3or_loss_event_rate);
}
+ 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);
+ ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
+ dccp_role(sk), sk,
+ opt_recv->ccid3or_receive_rate);
+ }
+ break;
}
- return 0;
+
+ return rc;
}
static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
{
struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
- hctx->hist = NULL;
- setup_timer(&hctx->no_feedback_timer,
- ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
+ hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
+ hctx->ccid3hctx_hist = NULL;
+ setup_timer(&hctx->ccid3hctx_no_feedback_timer,
+ ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
+
return 0;
}
@@ -520,36 +584,42 @@ static void ccid3_hc_tx_exit(struct sock *sk)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
- sk_stop_timer(sk, &hctx->no_feedback_timer);
- tfrc_tx_hist_purge(&hctx->hist);
+ ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
+ sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
+
+ tfrc_tx_hist_purge(&hctx->ccid3hctx_hist);
}
static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
{
- info->tcpi_rto = ccid3_hc_tx_sk(sk)->t_rto;
- info->tcpi_rtt = ccid3_hc_tx_sk(sk)->rtt;
+ struct ccid3_hc_tx_sock *hctx;
+
+ /* Listen socks doesn't have a private CCID block */
+ if (sk->sk_state == DCCP_LISTEN)
+ return;
+
+ hctx = ccid3_hc_tx_sk(sk);
+ info->tcpi_rto = hctx->ccid3hctx_t_rto;
+ info->tcpi_rtt = hctx->ccid3hctx_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 *hctx = ccid3_hc_tx_sk(sk);
- struct tfrc_tx_info tfrc;
+ const struct ccid3_hc_tx_sock *hctx;
const void *val;
+ /* Listen socks doesn't have a private CCID block */
+ if (sk->sk_state == DCCP_LISTEN)
+ return -EINVAL;
+
+ hctx = ccid3_hc_tx_sk(sk);
switch (optname) {
case DCCP_SOCKOPT_CCID_TX_INFO:
- if (len < sizeof(tfrc))
+ if (len < sizeof(hctx->ccid3hctx_tfrc))
return -EINVAL;
- tfrc.tfrctx_x = hctx->x;
- tfrc.tfrctx_x_recv = hctx->x_recv;
- tfrc.tfrctx_x_calc = hctx->x_calc;
- tfrc.tfrctx_rtt = hctx->rtt;
- tfrc.tfrctx_p = hctx->p;
- tfrc.tfrctx_rto = hctx->t_rto;
- tfrc.tfrctx_ipi = hctx->t_ipi;
- len = sizeof(tfrc);
- val = &tfrc;
+ len = sizeof(hctx->ccid3hctx_tfrc);
+ val = &hctx->ccid3hctx_tfrc;
break;
default:
return -ENOPROTOOPT;
@@ -564,82 +634,112 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
/*
* Receiver Half-Connection Routines
*/
+
+/* CCID3 feedback types */
+enum ccid3_fback_type {
+ CCID3_FBACK_NONE = 0,
+ CCID3_FBACK_INITIAL,
+ CCID3_FBACK_PERIODIC,
+ CCID3_FBACK_PARAM_CHANGE
+};
+
+#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
+static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
+{
+ static char *ccid3_rx_state_names[] = {
+ [TFRC_RSTATE_NO_DATA] = "NO_DATA",
+ [TFRC_RSTATE_DATA] = "DATA",
+ [TFRC_RSTATE_TERM] = "TERM",
+ };
+
+ return ccid3_rx_state_names[state];
+}
+#endif
+
+static void ccid3_hc_rx_set_state(struct sock *sk,
+ enum ccid3_hc_rx_states state)
+{
+ struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+ enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
+
+ ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
+ dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
+ ccid3_rx_state_name(state));
+ WARN_ON(state == oldstate);
+ hcrx->ccid3hcrx_state = state;
+}
+
static void ccid3_hc_rx_send_feedback(struct sock *sk,
const struct sk_buff *skb,
enum ccid3_fback_type fbtype)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+ struct dccp_sock *dp = dccp_sk(sk);
+ ktime_t now;
+ s64 delta = 0;
+
+ if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_TERM))
+ return;
+
+ now = ktime_get_real();
switch (fbtype) {
case CCID3_FBACK_INITIAL:
- hcrx->x_recv = 0;
- hcrx->p_inverse = ~0U; /* see RFC 4342, 8.5 */
+ hcrx->ccid3hcrx_x_recv = 0;
+ hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
break;
case CCID3_FBACK_PARAM_CHANGE:
- if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) {
- /*
- * rfc3448bis-06, 6.3.1: First packet(s) lost or marked
- * FIXME: in rfc3448bis the receiver returns X_recv=0
- * here as it normally would in the first feedback packet.
- * However this is not possible yet, since the code still
- * uses RFC 3448, i.e.
- * If (p > 0)
- * Calculate X_calc using the TCP throughput equation.
- * X = max(min(X_calc, 2*X_recv), s/t_mbi);
- * would bring X down to s/t_mbi. That is why we return
- * X_recv according to rfc3448bis-06 for the moment.
- */
- u32 s = tfrc_rx_hist_packet_size(&hcrx->hist),
- rtt = tfrc_rx_hist_rtt(&hcrx->hist);
-
- hcrx->x_recv = scaled_div32(s, 2 * rtt);
- break;
- }
/*
* When parameters change (new loss or p > p_prev), we do not
* have a reliable estimate for R_m of [RFC 3448, 6.2] and so
- * always check whether at least RTT time units were covered.
+ * need to reuse the previous value of X_recv. However, when
+ * X_recv was 0 (due to early loss), this would kill X down to
+ * s/t_mbi (i.e. one packet in 64 seconds).
+ * To avoid such drastic reduction, we approximate X_recv as
+ * the number of bytes since last feedback.
+ * This is a safe fallback, since X is bounded above by X_calc.
*/
- hcrx->x_recv = tfrc_rx_hist_x_recv(&hcrx->hist, hcrx->x_recv);
- break;
+ if (hcrx->ccid3hcrx_x_recv > 0)
+ break;
+ /* fall through */
case CCID3_FBACK_PERIODIC:
- /*
- * Step (2) of rfc3448bis-06, 6.2:
- * - if no data packets have been received, just restart timer
- * - if data packets have been received, re-compute X_recv
- */
- if (hcrx->hist.bytes_recvd == 0)
- goto prepare_for_next_time;
- hcrx->x_recv = tfrc_rx_hist_x_recv(&hcrx->hist, hcrx->x_recv);
+ delta = ktime_us_delta(now, hcrx->ccid3hcrx_tstamp_last_feedback);
+ if (delta <= 0)
+ DCCP_BUG("delta (%ld) <= 0", (long)delta);
+ else
+ hcrx->ccid3hcrx_x_recv =
+ scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
break;
default:
return;
}
- ccid3_pr_debug("X_recv=%u, 1/p=%u\n", hcrx->x_recv, hcrx->p_inverse);
+ ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta,
+ hcrx->ccid3hcrx_x_recv, hcrx->ccid3hcrx_pinv);
- dccp_sk(sk)->dccps_hc_rx_insert_options = 1;
- dccp_send_ack(sk);
+ hcrx->ccid3hcrx_tstamp_last_feedback = now;
+ hcrx->ccid3hcrx_last_counter = dccp_hdr(skb)->dccph_ccval;
+ hcrx->ccid3hcrx_bytes_recv = 0;
-prepare_for_next_time:
- tfrc_rx_hist_restart_byte_counter(&hcrx->hist);
- hcrx->last_counter = dccp_hdr(skb)->dccph_ccval;
- hcrx->feedback = fbtype;
+ dp->dccps_hc_rx_insert_options = 1;
+ dccp_send_ack(sk);
}
static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
{
- const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+ const struct ccid3_hc_rx_sock *hcrx;
__be32 x_recv, pinv;
if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
return 0;
+ hcrx = ccid3_hc_rx_sk(sk);
+
if (dccp_packet_without_ack(skb))
return 0;
- x_recv = htonl(hcrx->x_recv);
- pinv = htonl(hcrx->p_inverse);
+ x_recv = htonl(hcrx->ccid3hcrx_x_recv);
+ pinv = htonl(hcrx->ccid3hcrx_pinv);
if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
&pinv, sizeof(pinv)) ||
@@ -662,95 +762,171 @@ 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 s = tfrc_rx_hist_packet_size(&hcrx->hist),
- rtt = tfrc_rx_hist_rtt(&hcrx->hist), x_recv, p;
+ u32 x_recv, p, delta;
u64 fval;
- /*
- * rfc3448bis-06, 6.3.1: First data packet(s) are marked or lost. Set p
- * to give the equivalent of X_target = s/(2*R). Thus fval = 2 and so p
- * is about 20.64%. This yields an interval length of 4.84 (rounded up).
- */
- if (unlikely(hcrx->feedback == CCID3_FBACK_NONE))
- return 5;
+ if (hcrx->ccid3hcrx_rtt == 0) {
+ DCCP_WARN("No RTT estimate available, using fallback RTT\n");
+ hcrx->ccid3hcrx_rtt = DCCP_FALLBACK_RTT;
+ }
- x_recv = tfrc_rx_hist_x_recv(&hcrx->hist, hcrx->x_recv);
- if (x_recv == 0)
- goto failed;
+ delta = ktime_to_us(net_timedelta(hcrx->ccid3hcrx_tstamp_last_feedback));
+ x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
+ if (x_recv == 0) { /* would also trigger divide-by-zero */
+ DCCP_WARN("X_recv==0\n");
+ if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
+ DCCP_BUG("stored value of X_recv is zero");
+ return ~0U;
+ }
+ }
- fval = scaled_div32(scaled_div(s, rtt), x_recv);
+ fval = scaled_div(hcrx->ccid3hcrx_s, hcrx->ccid3hcrx_rtt);
+ fval = scaled_div32(fval, x_recv);
p = tfrc_calc_x_reverse_lookup(fval);
ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
"loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
- if (p > 0)
- return scaled_div(1, p);
-failed:
- return UINT_MAX;
+ return p == 0 ? ~0U : scaled_div(1, p);
}
static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+ enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
const bool is_data_packet = dccp_data_packet(skb);
+ if (unlikely(hcrx->ccid3hcrx_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->ccid3hcrx_s = payload;
+ /*
+ * Not necessary to update ccid3hcrx_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->ccid3hcrx_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->ccid3hcrx_s = tfrc_ewma(hcrx->ccid3hcrx_s, payload, 9);
+ hcrx->ccid3hcrx_bytes_recv += payload;
+ }
+
/*
* Perform loss detection and handle pending losses
*/
- if (tfrc_rx_congestion_event(&hcrx->hist, &hcrx->li_hist,
- skb, ndp, ccid3_first_li, sk))
- ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PARAM_CHANGE);
+ if (tfrc_rx_handle_loss(&hcrx->ccid3hcrx_hist, &hcrx->ccid3hcrx_li_hist,
+ skb, ndp, ccid3_first_li, sk)) {
+ do_feedback = CCID3_FBACK_PARAM_CHANGE;
+ goto done_receiving;
+ }
+
+ if (tfrc_rx_hist_loss_pending(&hcrx->ccid3hcrx_hist))
+ return; /* done receiving */
+
/*
- * Feedback for first non-empty data packet (RFC 3448, 6.3)
+ * Handle data packets: RTT sampling and monitoring p
*/
- else if (unlikely(hcrx->feedback == CCID3_FBACK_NONE && is_data_packet))
- ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_INITIAL);
+ if (unlikely(!is_data_packet))
+ goto update_records;
+
+ if (!tfrc_lh_is_initialised(&hcrx->ccid3hcrx_li_hist)) {
+ const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->ccid3hcrx_hist, skb);
+ /*
+ * Empty loss history: no loss so far, hence p stays 0.
+ * Sample RTT values, since an RTT estimate is required for the
+ * computation of p when the first loss occurs; RFC 3448, 6.3.1.
+ */
+ if (sample != 0)
+ hcrx->ccid3hcrx_rtt = tfrc_ewma(hcrx->ccid3hcrx_rtt, sample, 9);
+
+ } else if (tfrc_lh_update_i_mean(&hcrx->ccid3hcrx_li_hist, skb)) {
+ /*
+ * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
+ * has decreased (resp. p has increased), send feedback now.
+ */
+ do_feedback = CCID3_FBACK_PARAM_CHANGE;
+ }
+
/*
* Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
*/
- else if (!tfrc_rx_hist_loss_pending(&hcrx->hist) && is_data_packet &&
- SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3)
- ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PERIODIC);
+ if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->ccid3hcrx_last_counter) > 3)
+ do_feedback = CCID3_FBACK_PERIODIC;
+
+update_records:
+ tfrc_rx_hist_add_packet(&hcrx->ccid3hcrx_hist, skb, ndp);
+
+done_receiving:
+ if (do_feedback)
+ ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
}
static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
- tfrc_lh_init(&hcrx->li_hist);
- return tfrc_rx_hist_init(&hcrx->hist, sk);
+ hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
+ tfrc_lh_init(&hcrx->ccid3hcrx_li_hist);
+ return tfrc_rx_hist_alloc(&hcrx->ccid3hcrx_hist);
}
static void ccid3_hc_rx_exit(struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
- tfrc_rx_hist_purge(&hcrx->hist);
- tfrc_lh_cleanup(&hcrx->li_hist);
+ ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
+
+ tfrc_rx_hist_purge(&hcrx->ccid3hcrx_hist);
+ tfrc_lh_cleanup(&hcrx->ccid3hcrx_li_hist);
}
static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
{
+ const struct ccid3_hc_rx_sock *hcrx;
+
+ /* Listen socks doesn't have a private CCID block */
+ if (sk->sk_state == DCCP_LISTEN)
+ return;
+
+ hcrx = ccid3_hc_rx_sk(sk);
+ info->tcpi_ca_state = hcrx->ccid3hcrx_state;
info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
- info->tcpi_rcv_rtt = tfrc_rx_hist_rtt(&ccid3_hc_rx_sk(sk)->hist);
+ info->tcpi_rcv_rtt = hcrx->ccid3hcrx_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 *hcrx = ccid3_hc_rx_sk(sk);
+ const struct ccid3_hc_rx_sock *hcrx;
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;
+
+ hcrx = 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 = hcrx->x_recv;
- rx_info.tfrcrx_rtt = tfrc_rx_hist_rtt(&hcrx->hist);
- rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hcrx->p_inverse);
+ rx_info.tfrcrx_x_recv = hcrx->ccid3hcrx_x_recv;
+ rx_info.tfrcrx_rtt = hcrx->ccid3hcrx_rtt;
+ rx_info.tfrcrx_p = hcrx->ccid3hcrx_pinv == 0 ? ~0U :
+ scaled_div(1, hcrx->ccid3hcrx_pinv);
len = sizeof(rx_info);
val = &rx_info;
break;
@@ -786,9 +962,6 @@ static struct ccid_operations ccid3 = {
.ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
};
-module_param(do_osc_prev, bool, 0644);
-MODULE_PARM_DESC(do_osc_prev, "Use Oscillation Prevention (RFC 3448, 4.5)");
-
#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
module_param(ccid3_debug, bool, 0644);
MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
@@ -796,19 +969,6 @@ MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
static __init int ccid3_module_init(void)
{
- struct timespec tp;
-
- /*
- * Without a fine-grained clock resolution, RTTs/X_recv are not sampled
- * correctly and feedback is sent either too early or too late.
- */
- hrtimer_get_res(CLOCK_MONOTONIC, &tp);
- if (tp.tv_sec || tp.tv_nsec > DCCP_TIME_RESOLUTION * NSEC_PER_USEC) {
- printk(KERN_ERR "%s: Timer too coarse (%ld usec), need %u-usec"
- " resolution - check your clocksource.\n", __func__,
- tp.tv_nsec/NSEC_PER_USEC, DCCP_TIME_RESOLUTION);
- return -ESOCKTNOSUPPORT;
- }
return ccid_register(&ccid3);
}
module_init(ccid3_module_init);
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index af6e1bf937d9..49ca32bd7e79 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -47,22 +47,11 @@
/* Two seconds as per RFC 3448 4.2 */
#define TFRC_INITIAL_TIMEOUT (2 * USEC_PER_SEC)
-/* Maximum backoff interval t_mbi (RFC 3448, 4.3) */
-#define TFRC_T_MBI (64 * 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))
-/*
- * The t_delta parameter (RFC 3448, 4.6): 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))
-#warning Coarse CONFIG_HZ resolution -- higher value recommended for TFRC.
-#endif
+/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
+#define TFRC_T_MBI 64
enum ccid3_options {
TFRC_OPT_LOSS_EVENT_RATE = 192,
@@ -70,43 +59,62 @@ enum ccid3_options {
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,
+};
+
/** struct ccid3_hc_tx_sock - CCID3 sender half-connection socket
*
- * @x - Current sending rate in 64 * bytes per second
- * @x_recv - Receive rate in 64 * bytes per second
- * @x_calc - Calculated rate in bytes per second
- * @rtt - Estimate of current round trip time in usecs
- * @r_sqmean - Estimate of long-term RTT (RFC 3448, 4.5)
- * @p - Current loss event rate (0-1) scaled by 1000000
- * @s - Packet size in bytes
- * @t_rto - Nofeedback Timer setting in usecs
- * @t_ipi - Interpacket (send) interval (RFC 3448, 4.6) in usecs
- * @feedback - Whether feedback has been received or not
- * @last_win_count - Last window counter sent
- * @t_last_win_count - Timestamp of earliest packet with
- * last_win_count value sent
- * @no_feedback_timer - Handle to no feedback timer
- * @t_ld - Time last doubled during slow start
- * @t_nom - Nominal send time of next packet
- * @hist - Packet history
+ * @ccid3hctx_x - Current sending rate in 64 * bytes per second
+ * @ccid3hctx_x_recv - Receive rate in 64 * bytes per second
+ * @ccid3hctx_x_calc - Calculated rate in bytes per second
+ * @ccid3hctx_rtt - Estimate of current round trip time in usecs
+ * @ccid3hctx_p - Current loss event rate (0-1) scaled by 1000000
+ * @ccid3hctx_s - Packet size in bytes
+ * @ccid3hctx_t_rto - Nofeedback Timer setting in usecs
+ * @ccid3hctx_t_ipi - Interpacket (send) interval (RFC 3448, 4.6) in usecs
+ * @ccid3hctx_state - Sender state, one of %ccid3_hc_tx_states
+ * @ccid3hctx_last_win_count - Last window counter sent
+ * @ccid3hctx_t_last_win_count - Timestamp of earliest packet
+ * with last_win_count value sent
+ * @ccid3hctx_no_feedback_timer - Handle to no feedback timer
+ * @ccid3hctx_t_ld - Time last doubled during slow start
+ * @ccid3hctx_t_nom - Nominal send time of next packet
+ * @ccid3hctx_delta - Send timer delta (RFC 3448, 4.6) in usecs
+ * @ccid3hctx_hist - Packet history
+ * @ccid3hctx_options_received - Parsed set of retrieved options
*/
struct ccid3_hc_tx_sock {
- u64 x;
- u64 x_recv;
- u32 x_calc;
- u32 rtt;
- u16 r_sqmean;
- u32 p;
- u32 t_rto;
- u32 t_ipi;
- u16 s;
- bool feedback:1;
- u8 last_win_count;
- ktime_t t_last_win_count;
- struct timer_list no_feedback_timer;
- ktime_t t_ld;
- ktime_t t_nom;
- struct tfrc_tx_hist_entry *hist;
+ struct tfrc_tx_info ccid3hctx_tfrc;
+#define ccid3hctx_x ccid3hctx_tfrc.tfrctx_x
+#define ccid3hctx_x_recv ccid3hctx_tfrc.tfrctx_x_recv
+#define ccid3hctx_x_calc ccid3hctx_tfrc.tfrctx_x_calc
+#define ccid3hctx_rtt ccid3hctx_tfrc.tfrctx_rtt
+#define ccid3hctx_p ccid3hctx_tfrc.tfrctx_p
+#define ccid3hctx_t_rto ccid3hctx_tfrc.tfrctx_rto
+#define ccid3hctx_t_ipi ccid3hctx_tfrc.tfrctx_ipi
+ u16 ccid3hctx_s;
+ enum ccid3_hc_tx_states ccid3hctx_state:8;
+ u8 ccid3hctx_last_win_count;
+ ktime_t ccid3hctx_t_last_win_count;
+ struct timer_list ccid3hctx_no_feedback_timer;
+ ktime_t ccid3hctx_t_ld;
+ ktime_t ccid3hctx_t_nom;
+ u32 ccid3hctx_delta;
+ struct tfrc_tx_hist_entry *ccid3hctx_hist;
+ struct ccid3_options_received ccid3hctx_options_received;
};
static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
@@ -116,32 +124,41 @@ static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
return hctx;
}
-
-enum ccid3_fback_type {
- CCID3_FBACK_NONE = 0,
- CCID3_FBACK_INITIAL,
- CCID3_FBACK_PERIODIC,
- CCID3_FBACK_PARAM_CHANGE
+/* TFRC receiver states */
+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
*
- * @last_counter - Tracks window counter (RFC 4342, 8.1)
- * @feedback - The type of the feedback last sent
- * @x_recv - Receiver estimate of send rate (RFC 3448, sec. 4.3)
- * @tstamp_last_feedback - Time at which last feedback was sent
- * @hist - Packet history (loss detection + RTT sampling)
- * @li_hist - Loss Interval database
- * @p_inverse - Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
+ * @ccid3hcrx_x_recv - Receiver estimate of send rate (RFC 3448 4.3)
+ * @ccid3hcrx_rtt - Receiver estimate of rtt (non-standard)
+ * @ccid3hcrx_p - Current loss event rate (RFC 3448 5.4)
+ * @ccid3hcrx_last_counter - Tracks window counter (RFC 4342, 8.1)
+ * @ccid3hcrx_state - Receiver state, one of %ccid3_hc_rx_states
+ * @ccid3hcrx_bytes_recv - Total sum of DCCP payload bytes
+ * @ccid3hcrx_x_recv - Receiver estimate of send rate (RFC 3448, sec. 4.3)
+ * @ccid3hcrx_rtt - Receiver estimate of RTT
+ * @ccid3hcrx_tstamp_last_feedback - Time at which last feedback was sent
+ * @ccid3hcrx_tstamp_last_ack - Time at which last feedback was sent
+ * @ccid3hcrx_hist - Packet history (loss detection + RTT sampling)
+ * @ccid3hcrx_li_hist - Loss Interval database
+ * @ccid3hcrx_s - Received packet size in bytes
+ * @ccid3hcrx_pinv - Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
*/
struct ccid3_hc_rx_sock {
- u8 last_counter:4;
- enum ccid3_fback_type feedback:4;
- u32 x_recv;
- ktime_t tstamp_last_feedback;
- struct tfrc_rx_hist hist;
- struct tfrc_loss_hist li_hist;
-#define p_inverse li_hist.i_mean
+ u8 ccid3hcrx_last_counter:4;
+ enum ccid3_hc_rx_states ccid3hcrx_state:8;
+ u32 ccid3hcrx_bytes_recv;
+ u32 ccid3hcrx_x_recv;
+ u32 ccid3hcrx_rtt;
+ ktime_t ccid3hcrx_tstamp_last_feedback;
+ struct tfrc_rx_hist ccid3hcrx_hist;
+ struct tfrc_loss_hist ccid3hcrx_li_hist;
+ u16 ccid3hcrx_s;
+#define ccid3hcrx_pinv ccid3hcrx_li_hist.i_mean
};
static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index b1ae8f8259e5..5b3ce0688c5c 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -86,26 +86,21 @@ static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
/**
* tfrc_lh_update_i_mean - Update the `open' loss interval I_0
- * This updates I_mean as the sequence numbers increase. As a consequence, the
- * open loss interval I_0 increases, hence p = W_tot/max(I_tot0, I_tot1)
- * decreases, and thus there is no need to send renewed feedback.
+ * For recomputing p: returns `true' if p > p_prev <=> 1/p < 1/p_prev
*/
-void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
+u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
{
struct tfrc_loss_interval *cur = tfrc_lh_peek(lh);
+ u32 old_i_mean = lh->i_mean;
s64 len;
if (cur == NULL) /* not initialised */
- return;
-
- /* FIXME: should probably also count non-data packets (RFC 4342, 6.1) */
- if (!dccp_data_packet(skb))
- return;
+ return 0;
len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1;
if (len - (s64)cur->li_length <= 0) /* duplicate or reordered */
- return;
+ return 0;
if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4)
/*
@@ -119,11 +114,14 @@ void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
cur->li_is_closed = 1;
if (tfrc_lh_length(lh) == 1) /* due to RFC 3448, 6.3.1 */
- return;
+ return 0;
cur->li_length = len;
tfrc_lh_calc_i_mean(lh);
+
+ return (lh->i_mean < old_i_mean);
}
+EXPORT_SYMBOL_GPL(tfrc_lh_update_i_mean);
/* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
@@ -140,18 +138,18 @@ static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
* @sk: Used by @calc_first_li in caller-specific way (subtyping)
* Updates I_mean and returns 1 if a new interval has in fact been added to @lh.
*/
-bool tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
- u32 (*calc_first_li)(struct sock *), struct sock *sk)
+int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
+ u32 (*calc_first_li)(struct sock *), struct sock *sk)
{
struct tfrc_loss_interval *cur = tfrc_lh_peek(lh), *new;
if (cur != NULL && !tfrc_lh_is_new_loss(cur, tfrc_rx_hist_loss_prev(rh)))
- return false;
+ return 0;
new = tfrc_lh_demand_next(lh);
if (unlikely(new == NULL)) {
DCCP_CRIT("Cannot allocate/add loss record.");
- return false;
+ return 0;
}
new->li_seqno = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno;
@@ -169,7 +167,7 @@ bool tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
tfrc_lh_calc_i_mean(lh);
}
- return true;
+ return 1;
}
EXPORT_SYMBOL_GPL(tfrc_lh_interval_add);
diff --git a/net/dccp/ccids/lib/loss_interval.h b/net/dccp/ccids/lib/loss_interval.h
index d08a226db43e..246018a3b269 100644
--- a/net/dccp/ccids/lib/loss_interval.h
+++ b/net/dccp/ccids/lib/loss_interval.h
@@ -67,9 +67,9 @@ static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
struct tfrc_rx_hist;
-extern bool tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
+extern int tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
u32 (*first_li)(struct sock *), struct sock *);
-extern void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
+extern u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
#endif /* _DCCP_LI_HIST_ */
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index cce9f03bda3e..6cc108afdc3b 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -40,6 +40,18 @@
#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
*/
@@ -61,6 +73,15 @@ 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());
@@ -90,6 +111,25 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
}
EXPORT_SYMBOL_GPL(tfrc_tx_hist_purge);
+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;
+}
+EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt);
+
+
/*
* Receiver History Routines
*/
@@ -151,31 +191,14 @@ int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb)
}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate);
-
-static void __tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b)
-{
- struct tfrc_rx_hist_entry *tmp = h->ring[a];
-
- h->ring[a] = h->ring[b];
- h->ring[b] = tmp;
-}
-
static void tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b)
{
- __tfrc_rx_hist_swap(h, tfrc_rx_hist_index(h, a),
- tfrc_rx_hist_index(h, b));
-}
+ const u8 idx_a = tfrc_rx_hist_index(h, a),
+ idx_b = tfrc_rx_hist_index(h, b);
+ struct tfrc_rx_hist_entry *tmp = h->ring[idx_a];
-/**
- * tfrc_rx_hist_resume_rtt_sampling - Prepare RX history for RTT sampling
- * This is called after loss detection has finished, when the history entry
- * with the index of `loss_count' holds the highest-received sequence number.
- * RTT sampling requires this information at ring[0] (tfrc_rx_hist_sample_rtt).
- */
-static inline void tfrc_rx_hist_resume_rtt_sampling(struct tfrc_rx_hist *h)
-{
- __tfrc_rx_hist_swap(h, 0, tfrc_rx_hist_index(h, h->loss_count));
- h->loss_count = h->loss_start = 0;
+ h->ring[idx_a] = h->ring[idx_b];
+ h->ring[idx_b] = tmp;
}
/*
@@ -192,8 +215,10 @@ static void __do_track_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u64 n1)
u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
s1 = DCCP_SKB_CB(skb)->dccpd_seq;
- if (!dccp_loss_free(s0, s1, n1)) /* gap between S0 and S1 */
+ if (!dccp_loss_free(s0, s1, n1)) { /* gap between S0 and S1 */
h->loss_count = 1;
+ tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n1);
+ }
}
static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2)
@@ -215,7 +240,8 @@ static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2
if (dccp_loss_free(s2, s1, n1)) {
/* hole is filled: S0, S2, and S1 are consecutive */
- tfrc_rx_hist_resume_rtt_sampling(h);
+ h->loss_count = 0;
+ h->loss_start = tfrc_rx_hist_index(h, 1);
} else
/* gap between S2 and S1: just update loss_prev */
tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_loss_prev(h), skb, n2);
@@ -268,7 +294,8 @@ static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3)
if (dccp_loss_free(s1, s2, n2)) {
/* entire hole filled by S0, S3, S1, S2 */
- tfrc_rx_hist_resume_rtt_sampling(h);
+ h->loss_start = tfrc_rx_hist_index(h, 2);
+ h->loss_count = 0;
} else {
/* gap remains between S1 and S2 */
h->loss_start = tfrc_rx_hist_index(h, 1);
@@ -312,7 +339,8 @@ static void __three_after_loss(struct tfrc_rx_hist *h)
if (dccp_loss_free(s2, s3, n3)) {
/* no gap between S2 and S3: entire hole is filled */
- tfrc_rx_hist_resume_rtt_sampling(h);
+ h->loss_start = tfrc_rx_hist_index(h, 3);
+ h->loss_count = 0;
} else {
/* gap between S2 and S3 */
h->loss_start = tfrc_rx_hist_index(h, 2);
@@ -326,13 +354,13 @@ static void __three_after_loss(struct tfrc_rx_hist *h)
}
/**
- * tfrc_rx_congestion_event - Loss detection and further processing
- * @h: The non-empty RX history object
- * @lh: Loss Intervals database to update
- * @skb: Currently received packet
- * @ndp: The NDP count belonging to @skb
- * @first_li: Caller-dependent computation of first loss interval in @lh
- * @sk: Used by @calc_first_li (see tfrc_lh_interval_add)
+ * tfrc_rx_handle_loss - Loss detection and further processing
+ * @h: The non-empty RX history object
+ * @lh: Loss Intervals database to update
+ * @skb: Currently received packet
+ * @ndp: The NDP count belonging to @skb
+ * @calc_first_li: Caller-dependent computation of first loss interval in @lh
+ * @sk: Used by @calc_first_li (see tfrc_lh_interval_add)
* Chooses action according to pending loss, updates LI database when a new
* loss was detected, and does required post-processing. Returns 1 when caller
* should send feedback, 0 otherwise.
@@ -340,20 +368,15 @@ static void __three_after_loss(struct tfrc_rx_hist *h)
* records accordingly, the caller should not perform any more RX history
* operations when loss_count is greater than 0 after calling this function.
*/
-bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h,
- struct tfrc_loss_hist *lh,
- struct sk_buff *skb, const u64 ndp,
- u32 (*first_li)(struct sock *), struct sock *sk)
+int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
+ struct tfrc_loss_hist *lh,
+ struct sk_buff *skb, const u64 ndp,
+ u32 (*calc_first_li)(struct sock *), struct sock *sk)
{
- bool new_event = false;
-
- if (tfrc_rx_hist_duplicate(h, skb))
- return 0;
+ int is_new_loss = 0;
if (h->loss_count == 0) {
__do_track_loss(h, skb, ndp);
- tfrc_rx_hist_sample_rtt(h, skb);
- tfrc_rx_hist_add_packet(h, skb, ndp);
} else if (h->loss_count == 1) {
__one_after_loss(h, skb, ndp);
} else if (h->loss_count != 2) {
@@ -362,57 +385,34 @@ bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h,
/*
* Update Loss Interval database and recycle RX records
*/
- new_event = tfrc_lh_interval_add(lh, h, first_li, sk);
+ is_new_loss = tfrc_lh_interval_add(lh, h, calc_first_li, sk);
__three_after_loss(h);
}
-
- /*
- * Update moving-average of `s' and the sum of received payload bytes.
- */
- if (dccp_data_packet(skb)) {
- const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
-
- h->packet_size = tfrc_ewma(h->packet_size, payload, 9);
- h->bytes_recvd += payload;
- }
-
- /* RFC 3448, 6.1: update I_0, whose growth implies p <= p_prev */
- if (!new_event)
- tfrc_lh_update_i_mean(lh, skb);
-
- return new_event;
+ return is_new_loss;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_congestion_event);
+EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);
-/* Compute the sending rate X_recv measured between feedback intervals */
-u32 tfrc_rx_hist_x_recv(struct tfrc_rx_hist *h, const u32 last_x_recv)
+int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
{
- u64 bytes = h->bytes_recvd, last_rtt = h->rtt_estimate;
- s64 delta = ktime_to_us(net_timedelta(h->bytes_start));
-
- WARN_ON(delta <= 0);
- /*
- * Ensure that the sampling interval for X_recv is at least one RTT,
- * by extending the sampling interval backwards in time, over the last
- * R_(m-1) seconds, as per rfc3448bis-06, 6.2.
- * To reduce noise (e.g. when the RTT changes often), this is only
- * done when delta is smaller than RTT/2.
- */
- if (last_x_recv > 0 && delta < last_rtt/2) {
- tfrc_pr_debug("delta < RTT ==> %ld us < %u us\n",
- (long)delta, (unsigned)last_rtt);
+ int i;
- delta = (bytes ? delta : 0) + last_rtt;
- bytes += div_u64((u64)last_x_recv * last_rtt, USEC_PER_SEC);
+ for (i = 0; i <= TFRC_NDUPACK; i++) {
+ h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
+ if (h->ring[i] == NULL)
+ goto out_free;
}
- if (unlikely(bytes == 0)) {
- DCCP_WARN("X_recv == 0, using old value of %u\n", last_x_recv);
- return last_x_recv;
+ h->loss_count = h->loss_start = 0;
+ return 0;
+
+out_free:
+ while (i-- != 0) {
+ kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
+ h->ring[i] = NULL;
}
- return scaled_div32(bytes, delta);
+ return -ENOBUFS;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_x_recv);
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);
void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
{
@@ -426,81 +426,73 @@ void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);
-static int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
+/**
+ * tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against
+ */
+static inline struct tfrc_rx_hist_entry *
+ tfrc_rx_hist_rtt_last_s(const struct tfrc_rx_hist *h)
{
- int i;
-
- memset(h, 0, sizeof(*h));
-
- for (i = 0; i <= TFRC_NDUPACK; i++) {
- h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
- if (h->ring[i] == NULL) {
- tfrc_rx_hist_purge(h);
- return -ENOBUFS;
- }
- }
- return 0;
+ return h->ring[0];
}
-int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk)
+/**
+ * tfrc_rx_hist_rtt_prev_s: previously suitable (wrt rtt_last_s) RTT-sampling entry
+ */
+static inline struct tfrc_rx_hist_entry *
+ tfrc_rx_hist_rtt_prev_s(const struct tfrc_rx_hist *h)
{
- if (tfrc_rx_hist_alloc(h))
- return -ENOBUFS;
- /*
- * Initialise first entry with GSR to start loss detection as early as
- * possible. Code using this must not use any other fields. The entry
- * will be overwritten once the CCID updates its received packets.
- */
- tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno = dccp_sk(sk)->dccps_gsr;
- return 0;
+ return h->ring[h->rtt_sample_prev];
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_init);
/**
* tfrc_rx_hist_sample_rtt - Sample RTT from timestamp / CCVal
- * Based on ideas presented in RFC 4342, 8.1. This function expects that no loss
- * is pending and uses the following history entries (via rtt_sample_prev):
- * - h->ring[0] contains the most recent history entry prior to @skb;
- * - h->ring[1] is an unused `dummy' entry when the current difference is 0;
+ * Based on ideas presented in RFC 4342, 8.1. Returns 0 if it was not able
+ * to compute a sample with given data - calling function should check this.
*/
-void tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb)
+u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb)
{
- struct tfrc_rx_hist_entry *last = h->ring[0];
- u32 sample, delta_v;
-
- /*
- * When not to sample:
- * - on non-data packets
- * (RFC 4342, 8.1: CCVal only fully defined for data packets);
- * - when no data packets have been received yet
- * (FIXME: using sampled packet size as indicator here);
- * - as long as there are gaps in the sequence space (pending loss).
- */
- if (!dccp_data_packet(skb) || h->packet_size == 0 ||
- tfrc_rx_hist_loss_pending(h))
- return;
+ u32 sample = 0,
+ delta_v = SUB16(dccp_hdr(skb)->dccph_ccval,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+
+ if (delta_v < 1 || delta_v > 4) { /* unsuitable CCVal delta */
+ if (h->rtt_sample_prev == 2) { /* previous candidate stored */
+ sample = SUB16(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+ if (sample)
+ sample = 4 / sample *
+ ktime_us_delta(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_tstamp,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp);
+ else /*
+ * FIXME: This condition is in principle not
+ * possible but occurs when CCID is used for
+ * two-way data traffic. I have tried to trace
+ * it, but the cause does not seem to be here.
+ */
+ DCCP_BUG("please report to dccp@vger.kernel.org"
+ " => prev = %u, last = %u",
+ tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+ } else if (delta_v < 1) {
+ h->rtt_sample_prev = 1;
+ goto keep_ref_for_next_time;
+ }
- h->rtt_sample_prev = 0; /* reset previous candidate */
+ } else if (delta_v == 4) /* optimal match */
+ sample = ktime_to_us(net_timedelta(tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp));
+ else { /* suboptimal match */
+ h->rtt_sample_prev = 2;
+ goto keep_ref_for_next_time;
+ }
- delta_v = SUB16(dccp_hdr(skb)->dccph_ccval, last->tfrchrx_ccval);
- if (delta_v == 0) { /* less than RTT/4 difference */
- h->rtt_sample_prev = 1;
- return;
+ if (unlikely(sample > DCCP_SANE_RTT_MAX)) {
+ DCCP_WARN("RTT sample %u too large, using max\n", sample);
+ sample = DCCP_SANE_RTT_MAX;
}
- sample = dccp_sane_rtt(ktime_to_us(net_timedelta(last->tfrchrx_tstamp)));
- if (delta_v <= 4) /* between RTT/4 and RTT */
- sample *= 4 / delta_v;
- else if (!(sample < h->rtt_estimate && sample > h->rtt_estimate/2))
- /*
- * Optimisation: CCVal difference is greater than 1 RTT, yet the
- * sample is less than the local RTT estimate; which means that
- * the RTT estimate is too high.
- * To avoid noise, it is not done if the sample is below RTT/2.
- */
- return;
+ h->rtt_sample_prev = 0; /* use current entry as next reference */
+keep_ref_for_next_time:
- /* Use a lower weight than usual to increase responsiveness */
- h->rtt_estimate = tfrc_ewma(h->rtt_estimate, sample, 5);
+ return sample;
}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_sample_rtt);
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 555e65cd73a0..461cc91cce88 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -40,28 +40,12 @@
#include <linux/slab.h>
#include "tfrc.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;
-};
-
-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;
-}
+struct tfrc_tx_hist_entry;
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)
@@ -91,22 +75,12 @@ struct tfrc_rx_hist_entry {
* @loss_count: Number of entries in circular history
* @loss_start: Movable index (for loss detection)
* @rtt_sample_prev: Used during RTT sampling, points to candidate entry
- * @rtt_estimate: Receiver RTT estimate
- * @packet_size: Packet size in bytes (as per RFC 3448, 3.1)
- * @bytes_recvd: Number of bytes received since @bytes_start
- * @bytes_start: Start time for counting @bytes_recvd
*/
struct tfrc_rx_hist {
struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
u8 loss_count:2,
loss_start:2;
- /* Receiver RTT sampling */
#define rtt_sample_prev loss_start
- u32 rtt_estimate;
- /* Receiver sampling of application payload lengths */
- u32 packet_size,
- bytes_recvd;
- ktime_t bytes_start;
};
/**
@@ -150,50 +124,20 @@ static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
return h->loss_count > 0;
}
-/*
- * Accessor functions to retrieve parameters sampled by the RX history
- */
-static inline u32 tfrc_rx_hist_packet_size(const struct tfrc_rx_hist *h)
-{
- if (h->packet_size == 0) {
- DCCP_WARN("No sample for s, using fallback\n");
- return TCP_MIN_RCVMSS;
- }
- return h->packet_size;
-
-}
-static inline u32 tfrc_rx_hist_rtt(const struct tfrc_rx_hist *h)
-{
- if (h->rtt_estimate == 0) {
- DCCP_WARN("No RTT estimate available, using fallback RTT\n");
- return DCCP_FALLBACK_RTT;
- }
- return h->rtt_estimate;
-}
-
-static inline void tfrc_rx_hist_restart_byte_counter(struct tfrc_rx_hist *h)
-{
- h->bytes_recvd = 0;
- h->bytes_start = ktime_get_real();
-}
-
-extern u32 tfrc_rx_hist_x_recv(struct tfrc_rx_hist *h, const u32 last_x_recv);
-
-
extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
const struct sk_buff *skb, const u64 ndp);
extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
struct tfrc_loss_hist;
-extern bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h,
- struct tfrc_loss_hist *lh,
- struct sk_buff *skb, const u64 ndp,
- u32 (*first_li)(struct sock *sk),
- struct sock *sk);
-extern void tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,
- const struct sk_buff *skb);
-extern int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk);
+extern int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
+ struct tfrc_loss_hist *lh,
+ struct sk_buff *skb, const u64 ndp,
+ u32 (*first_li)(struct sock *sk),
+ struct sock *sk);
+extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,
+ const struct sk_buff *skb);
+extern int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
#endif /* _DCCP_PKT_HIST_ */
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index ede12f53de5a..ed9857527acf 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -48,21 +48,6 @@ static inline u32 scaled_div32(u64 a, u64 b)
}
/**
- * tfrc_scaled_sqrt - Compute scaled integer sqrt(x) for 0 < x < 2^22-1
- * Uses scaling to improve accuracy of the integer approximation of sqrt(). The
- * scaling factor of 2^10 limits the maximum @sample to 4e6; this is okay for
- * clamped RTT samples (dccp_sample_rtt).
- * Should best be used for expressions of type sqrt(x)/sqrt(y), since then the
- * scaling factor is neutralised. For this purpose, it avoids returning zero.
- */
-static inline u16 tfrc_scaled_sqrt(const u32 sample)
-{
- const unsigned long non_zero_sample = sample ? : 1;
-
- return int_sqrt(non_zero_sample << 10);
-}
-
-/**
* tfrc_ewma - Exponentially weighted moving average
* @weight: Weight to be used as damping factor, in units of 1/10
*/
@@ -73,7 +58,6 @@ 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 38239c4d5e14..2f20a29cffe4 100644
--- a/net/dccp/ccids/lib/tfrc_equation.c
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -632,16 +632,8 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p)
if (p <= TFRC_CALC_X_SPLIT) { /* 0.0000 < p <= 0.05 */
if (p < TFRC_SMALLEST_P) { /* 0.0000 < p < 0.0001 */
- /*
- * In the congestion-avoidance phase p decays towards 0
- * when there are no further losses, so this case is
- * natural. Truncating to p_min = 0.01% means that the
- * maximum achievable throughput is limited to about
- * X_calc_max = 122.4 * s/RTT (see RFC 3448, 3.1); e.g.
- * with s=1500 bytes, RTT=0.01 s: X_calc_max = 147 Mbps.
- */
- tfrc_pr_debug("Value of p (%d) below resolution. "
- "Substituting %d\n", p, TFRC_SMALLEST_P);
+ DCCP_WARN("Value of p (%d) below resolution. "
+ "Substituting %d\n", p, TFRC_SMALLEST_P);
index = 0;
} else /* 0.0001 <= p <= 0.05 */
index = p/TFRC_SMALLEST_P - 1;
@@ -666,6 +658,7 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p)
result = scaled_div(s, R);
return scaled_div32(result, f);
}
+
EXPORT_SYMBOL_GPL(tfrc_calc_x);
/**
@@ -700,19 +693,5 @@ u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
index = tfrc_binsearch(fvalue, 0);
return (index + 1) * 1000000 / TFRC_CALC_X_ARRSIZE;
}
-EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup);
-/**
- * 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);
-}
-EXPORT_SYMBOL_GPL(tfrc_invert_loss_event_rate);
+EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-22 23:25:47 +0000