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linux/net/dccp/ccids/ccid3.c
Gerrit Renker 49d66a70cf [CCID3]: Fix a bug in the send time processing 
ccid3_hc_tx_send_packet currently returns 0 when the time difference between
current time and t_nom is less than 1000 microseconds.

In this case the packet is sent immediately; but, unlike other packets that can
be emitted on first attempt, it will not have its window counter updated and
its options set as required. This is a bug.

Fix: Require the time difference to be at least 1000 microseconds. The
algorithm then converges: time differences > 1000 microseconds trigger the
timer in dccp_write_xmit; after timer expiry this function is tried again; when
the time difference is less than 1000, the packet will have its options added
and window counter updated as required.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
2007-07-10 22:15:34 -07:00

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/*
* net/dccp/ccids/ccid3.c
*
* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
*
* An implementation of the DCCP protocol
*
* This code has been developed by the University of Waikato WAND
* research group. For further information please see http://www.wand.net.nz/
*
* This code also uses code from Lulea University, rereleased as GPL by its
* authors:
* Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
*
* Changes to meet Linux coding standards, to make it meet latest ccid3 draft
* and to make it work as a loadable module in the DCCP stack written by
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
*
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "../ccid.h"
#include "../dccp.h"
#include "lib/packet_history.h"
#include "lib/loss_interval.h"
#include "lib/tfrc.h"
#include "ccid3.h"
#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
static int ccid3_debug;
#define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
#else
#define ccid3_pr_debug(format, a...)
#endif
static struct dccp_tx_hist *ccid3_tx_hist;
static struct dccp_rx_hist *ccid3_rx_hist;
/*
* Transmitter Half-Connection Routines
*/
#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 according to RFC 3390:
* w_init = min(4 * MSS, max(2 * MSS, 4380 bytes))
* X_init = w_init / RTT
* 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 struct dccp_sock *dp = dccp_sk(sk);
const __u32 w_init = min(4 * dp->dccps_mss_cache,
max(2 * dp->dccps_mss_cache, 4380U));
return scaled_div(w_init << 6, ccid3_hc_tx_sk(sk)->ccid3hctx_rtt);
}
/*
* Recalculate t_ipi and delta (should be called whenever X changes)
*/
static inline void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
{
/* 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));
}
/*
* Update X by
* If (p > 0)
* X_calc = calcX(s, R, p);
* X = max(min(X_calc, 2 * X_recv), s / t_mbi);
* Else
* If (now - tld >= R)
* X = max(min(2 * X, 2 * X_recv), s / R);
* tld = now;
*
* Note: X and X_recv are both stored in units of 64 * bytes/second, to support
* fine-grained resolution of sending rates. This requires scaling by 2^6
* throughout the code. Only X_calc is unscaled (in bytes/second).
*
*/
static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
__u64 min_rate = 2 * hctx->ccid3hctx_x_recv;
const __u64 old_x = hctx->ccid3hctx_x;
/*
* Handle IDLE periods: do not reduce below RFC3390 initial sending rate
* when idling [RFC 4342, 5.1]. See also draft-ietf-dccp-rfc3448bis.
* For consistency with X and X_recv, min_rate is also scaled by 2^6.
*/
if (unlikely(hctx->ccid3hctx_idle)) {
min_rate = rfc3390_initial_rate(sk);
min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
}
if (hctx->ccid3hctx_p > 0) {
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 (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
(suseconds_t)hctx->ccid3hctx_rtt >= 0) {
hctx->ccid3hctx_x =
max(min(2 * hctx->ccid3hctx_x, min_rate),
scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
hctx->ccid3hctx_rtt));
hctx->ccid3hctx_t_ld = *now;
}
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->ccid3hctx_x >> 6),
hctx->ccid3hctx_x_calc,
(unsigned)(hctx->ccid3hctx_x_recv >> 6));
ccid3_update_send_interval(hctx);
}
}
/*
* Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
* @len: DCCP packet payload size in bytes
*/
static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
{
const u16 old_s = hctx->ccid3hctx_s;
hctx->ccid3hctx_s = old_s == 0 ? len : (9 * old_s + len) / 10;
if (hctx->ccid3hctx_s != old_s)
ccid3_update_send_interval(hctx);
}
/*
* Update Window Counter using the algorithm from [RFC 4342, 8.1].
* The algorithm is not applicable if RTT < 4 microseconds.
*/
static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
ktime_t now)
{
u32 quarter_rtts;
if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
return;
quarter_rtts = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
quarter_rtts /= hctx->ccid3hctx_rtt / 4;
if (quarter_rtts > 0) {
hctx->ccid3hctx_t_last_win_count = now;
hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
}
}
static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
{
struct sock *sk = (struct sock *)data;
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
struct timeval now;
unsigned long t_nfb = USEC_PER_SEC / 5;
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) {
/* Try again later. */
/* XXX: set some sensible MIB */
goto restart_timer;
}
ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state));
hctx->ccid3hctx_idle = 1;
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_FBACK:
/* RFC 3448, 4.4: Halve send rate directly */
hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
(((__u64)hctx->ccid3hctx_s) << 6) /
TFRC_T_MBI);
ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
"bytes/s\n", dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state),
(unsigned)(hctx->ccid3hctx_x >> 6));
/* The value of R is still undefined and so we can not recompute
* the timout value. Keep initial value as per [RFC 4342, 5]. */
t_nfb = TFRC_INITIAL_TIMEOUT;
ccid3_update_send_interval(hctx);
break;
case TFRC_SSTATE_FBACK:
/*
* Modify the cached value of X_recv [RFC 3448, 4.4]
*
* If (p == 0 || X_calc > 2 * X_recv)
* X_recv = max(X_recv / 2, s / (2 * t_mbi));
* Else
* X_recv = X_calc / 4;
*
* Note that X_recv is scaled by 2^6 while X_calc is not
*/
BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
if (hctx->ccid3hctx_p == 0 ||
(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));
if (hctx->ccid3hctx_p == 0)
dccp_timestamp(sk, &now);
} else {
hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
hctx->ccid3hctx_x_recv <<= 4;
}
/* Now recalculate X [RFC 3448, 4.3, step (4)] */
ccid3_hc_tx_update_x(sk, &now);
/*
* Schedule no feedback timer to expire in
* max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
* See comments in packet_recv() regarding the value of t_RTO.
*/
t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
break;
case TFRC_SSTATE_NO_SENT:
DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
/* fall through */
case TFRC_SSTATE_TERM:
goto out;
}
restart_timer:
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + usecs_to_jiffies(t_nfb));
out:
bh_unlock_sock(sk);
sock_put(sk);
}
/*
* 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)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
ktime_t now = ktime_get_real();
s64 delay;
BUG_ON(hctx == NULL);
/*
* This function is called only for Data and DataAck packets. Sending
* zero-sized Data(Ack)s is theoretically possible, but for congestion
* control this case is pathological - ignore it.
*/
if (unlikely(skb->len == 0))
return -EBADMSG;
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->ccid3hctx_last_win_count = 0;
hctx->ccid3hctx_t_last_win_count = now;
/* Set t_0 for initial packet */
hctx->ccid3hctx_t_nom = now;
hctx->ccid3hctx_s = skb->len;
/*
* Use initial RTT sample when available: recommended by erratum
* to RFC 4342. This implements the initialisation procedure of
* draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
*/
if (dp->dccps_syn_rtt) {
ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
hctx->ccid3hctx_rtt = dp->dccps_syn_rtt;
hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
hctx->ccid3hctx_t_ld = ktime_to_timeval(now);
} else {
/* Sender does not have RTT sample: X = MSS/second */
hctx->ccid3hctx_x = dp->dccps_mss_cache;
hctx->ccid3hctx_x <<= 6;
}
ccid3_update_send_interval(hctx);
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]
*
* if (t_now > t_nom - delta)
* // send the packet now
* else
* // send the packet in (t_nom - t_now) milliseconds.
*/
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->ccid3hctx_last_win_count;
hctx->ccid3hctx_idle = 0;
/* set the nominal send time for the next following packet */
hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom,
hctx->ccid3hctx_t_ipi);
return 0;
}
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);
struct timeval now;
struct dccp_tx_hist_entry *packet;
BUG_ON(hctx == NULL);
ccid3_hc_tx_update_s(hctx, len);
packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC);
if (unlikely(packet == NULL)) {
DCCP_CRIT("packet history - out of memory!");
return;
}
dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
dccp_timestamp(sk, &now);
packet->dccphtx_tstamp = now;
packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
packet->dccphtx_sent = 1;
}
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 ccid3_options_received *opt_recv;
struct dccp_tx_hist_entry *packet;
struct timeval now;
unsigned long t_nfb;
u32 pinv, r_sample;
BUG_ON(hctx == NULL);
/* 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;
opt_recv = &hctx->ccid3hctx_options_received;
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
/* get packet from history to look up t_recvdata */
packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
DCCP_SKB_CB(skb)->dccpd_ack_seq);
if (unlikely(packet == NULL)) {
DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
"in history!\n", dccp_role(sk), sk,
(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
return;
}
/* 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 */
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 = 1000000 / pinv;
dccp_timestamp(sk, &now);
/*
* Calculate new round trip sample as per [RFC 3448, 4.3] by
* R_sample = (now - t_recvdata) - t_elapsed
*/
r_sample = dccp_sample_rtt(sk, &now, &packet->dccphtx_tstamp);
/*
* Update RTT estimate by
* If (No feedback recv)
* R = R_sample;
* Else
* R = q * R + (1 - q) * R_sample;
*
* q is a constant, RFC 3448 recomments 0.9
*/
if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
/*
* Larger Initial Windows [RFC 4342, sec. 5]
*/
hctx->ccid3hctx_rtt = r_sample;
hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
hctx->ccid3hctx_t_ld = now;
ccid3_update_send_interval(hctx);
ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
"R_sample=%uus, X=%u\n", dccp_role(sk),
sk, hctx->ccid3hctx_s,
dccp_sk(sk)->dccps_mss_cache, r_sample,
(unsigned)(hctx->ccid3hctx_x >> 6));
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
} else {
hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
r_sample) / 10;
/* Update sending rate (step 4 of [RFC 3448, 4.3]) */
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);
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->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->ccid3hctx_no_feedback_timer);
/* remove all packets older than the one acked from history */
dccp_tx_hist_purge_older(ccid3_tx_hist,
&hctx->ccid3hctx_hist, packet);
/*
* As we have calculated new ipi, delta, t_nom it is possible
* that we now can send a packet, so wake up dccp_wait_for_ccid
*/
sk->sk_write_space(sk);
/*
* Update timeout interval for the nofeedback timer.
* We use a configuration option to increase the lower bound.
* This can help avoid triggering the nofeedback timer too
* often ('spinning') on LANs with small RTTs.
*/
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->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);
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + usecs_to_jiffies(t_nfb));
/* set idle flag */
hctx->ccid3hctx_idle = 1;
break;
case TFRC_SSTATE_NO_SENT: /* fall through */
case TFRC_SSTATE_TERM: /* ignore feedback when closing */
break;
}
}
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;
BUG_ON(hctx == NULL);
opt_recv = &hctx->ccid3hctx_options_received;
if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
opt_recv->ccid3or_seqno = dp->dccps_gsr;
opt_recv->ccid3or_loss_event_rate = ~0;
opt_recv->ccid3or_loss_intervals_idx = 0;
opt_recv->ccid3or_loss_intervals_len = 0;
opt_recv->ccid3or_receive_rate = 0;
}
switch (option) {
case TFRC_OPT_LOSS_EVENT_RATE:
if (unlikely(len != 4)) {
DCCP_WARN("%s(%p), invalid len %d "
"for TFRC_OPT_LOSS_EVENT_RATE\n",
dccp_role(sk), sk, len);
rc = -EINVAL;
} else {
opt_recv->ccid3or_loss_event_rate =
ntohl(*(__be32 *)value);
ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
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_recv->ccid3or_receive_rate =
ntohl(*(__be32 *)value);
ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
dccp_role(sk), sk,
opt_recv->ccid3or_receive_rate);
}
break;
}
return rc;
}
static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
{
struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
hctx->ccid3hctx_s = 0;
hctx->ccid3hctx_rtt = 0;
hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
hctx->ccid3hctx_no_feedback_timer.function =
ccid3_hc_tx_no_feedback_timer;
hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
init_timer(&hctx->ccid3hctx_no_feedback_timer);
return 0;
}
static void ccid3_hc_tx_exit(struct sock *sk)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
BUG_ON(hctx == NULL);
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
/* Empty packet history */
dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
}
static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
{
const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
/* Listen socks doesn't have a private CCID block */
if (sk->sk_state == DCCP_LISTEN)
return;
BUG_ON(hctx == NULL);
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);
const void *val;
/* Listen socks doesn't have a private CCID block */
if (sk->sk_state == DCCP_LISTEN)
return -EINVAL;
switch (optname) {
case DCCP_SOCKOPT_CCID_TX_INFO:
if (len < sizeof(hctx->ccid3hctx_tfrc))
return -EINVAL;
len = sizeof(hctx->ccid3hctx_tfrc);
val = &hctx->ccid3hctx_tfrc;
break;
default:
return -ENOPROTOOPT;
}
if (put_user(len, optlen) || copy_to_user(optval, val, len))
return -EFAULT;
return 0;
}
/*
* Receiver Half-Connection Routines
*/
#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 inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
{
if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
ccid3_pr_debug("Packet payload length is 0 - not updating\n");
else
hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
(9 * hcrx->ccid3hcrx_s + len) / 10;
}
static void ccid3_hc_rx_send_feedback(struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_rx_hist_entry *packet;
struct timeval now;
suseconds_t delta;
ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
dccp_timestamp(sk, &now);
switch (hcrx->ccid3hcrx_state) {
case TFRC_RSTATE_NO_DATA:
hcrx->ccid3hcrx_x_recv = 0;
break;
case TFRC_RSTATE_DATA:
delta = timeval_delta(&now,
&hcrx->ccid3hcrx_tstamp_last_feedback);
DCCP_BUG_ON(delta < 0);
hcrx->ccid3hcrx_x_recv =
scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
break;
case TFRC_RSTATE_TERM:
DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
return;
}
packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
if (unlikely(packet == NULL)) {
DCCP_WARN("%s(%p), no data packet in history!\n",
dccp_role(sk), sk);
return;
}
hcrx->ccid3hcrx_tstamp_last_feedback = now;
hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
hcrx->ccid3hcrx_bytes_recv = 0;
/* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
delta = timeval_delta(&now, &packet->dccphrx_tstamp);
DCCP_BUG_ON(delta < 0);
hcrx->ccid3hcrx_elapsed_time = delta / 10;
if (hcrx->ccid3hcrx_p == 0)
hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
else if (hcrx->ccid3hcrx_p > 1000000) {
DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
} else
hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
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);
__be32 x_recv, pinv;
BUG_ON(hcrx == NULL);
if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
return 0;
DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
if (dccp_packet_without_ack(skb))
return 0;
x_recv = htonl(hcrx->ccid3hcrx_x_recv);
pinv = htonl(hcrx->ccid3hcrx_pinv);
if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
dccp_insert_option_elapsed_time(sk, skb,
hcrx->ccid3hcrx_elapsed_time)) ||
dccp_insert_option_timestamp(sk, skb) ||
dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
&pinv, sizeof(pinv)) ||
dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
&x_recv, sizeof(x_recv)))
return -1;
return 0;
}
static int ccid3_hc_rx_detect_loss(struct sock *sk,
struct dccp_rx_hist_entry *packet)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
struct dccp_rx_hist_entry *rx_hist =
dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
u64 seqno = packet->dccphrx_seqno;
u64 tmp_seqno;
int loss = 0;
u8 ccval;
tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
if (!rx_hist ||
follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
hcrx->ccid3hcrx_seqno_nonloss = seqno;
hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
goto detect_out;
}
while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
> TFRC_RECV_NUM_LATE_LOSS) {
loss = 1;
dccp_li_update_li(sk,
&hcrx->ccid3hcrx_li_hist,
&hcrx->ccid3hcrx_hist,
&hcrx->ccid3hcrx_tstamp_last_feedback,
hcrx->ccid3hcrx_s,
hcrx->ccid3hcrx_bytes_recv,
hcrx->ccid3hcrx_x_recv,
hcrx->ccid3hcrx_seqno_nonloss,
hcrx->ccid3hcrx_ccval_nonloss);
tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
dccp_inc_seqno(&tmp_seqno);
hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
dccp_inc_seqno(&tmp_seqno);
while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
tmp_seqno, &ccval)) {
hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
hcrx->ccid3hcrx_ccval_nonloss = ccval;
dccp_inc_seqno(&tmp_seqno);
}
}
/* FIXME - this code could be simplified with above while */
/* but works at moment */
if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
hcrx->ccid3hcrx_seqno_nonloss = seqno;
hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
}
detect_out:
dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
&hcrx->ccid3hcrx_li_hist, packet,
hcrx->ccid3hcrx_seqno_nonloss);
return loss;
}
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);
const struct dccp_options_received *opt_recv;
struct dccp_rx_hist_entry *packet;
struct timeval now;
u32 p_prev, r_sample, rtt_prev;
int loss, payload_size;
BUG_ON(hcrx == NULL);
opt_recv = &dccp_sk(sk)->dccps_options_received;
switch (DCCP_SKB_CB(skb)->dccpd_type) {
case DCCP_PKT_ACK:
if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
return;
case DCCP_PKT_DATAACK:
if (opt_recv->dccpor_timestamp_echo == 0)
break;
rtt_prev = hcrx->ccid3hcrx_rtt;
dccp_timestamp(sk, &now);
r_sample = dccp_sample_rtt(sk, &now, NULL);
if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
hcrx->ccid3hcrx_rtt = r_sample;
else
hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
r_sample / 10;
if (rtt_prev != hcrx->ccid3hcrx_rtt)
ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
opt_recv->dccpor_elapsed_time);
break;
case DCCP_PKT_DATA:
break;
default: /* We're not interested in other packet types, move along */
return;
}
packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
skb, GFP_ATOMIC);
if (unlikely(packet == NULL)) {
DCCP_WARN("%s(%p), Not enough mem to add rx packet "
"to history, consider it lost!\n", dccp_role(sk), sk);
return;
}
loss = ccid3_hc_rx_detect_loss(sk, packet);
if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
return;
payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
ccid3_hc_rx_update_s(hcrx, payload_size);
switch (hcrx->ccid3hcrx_state) {
case TFRC_RSTATE_NO_DATA:
ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
"feedback\n", dccp_role(sk), sk,
dccp_state_name(sk->sk_state), skb);
ccid3_hc_rx_send_feedback(sk);
ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
return;
case TFRC_RSTATE_DATA:
hcrx->ccid3hcrx_bytes_recv += payload_size;
if (loss)
break;
dccp_timestamp(sk, &now);
if ((timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
(suseconds_t)hcrx->ccid3hcrx_rtt) >= 0) {
hcrx->ccid3hcrx_tstamp_last_ack = now;
ccid3_hc_rx_send_feedback(sk);
}
return;
case TFRC_RSTATE_TERM:
DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
return;
}
/* Dealing with packet loss */
ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
dccp_role(sk), sk, dccp_state_name(sk->sk_state));
p_prev = hcrx->ccid3hcrx_p;
/* Calculate loss event rate */
if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
/* Scaling up by 1000000 as fixed decimal */
if (i_mean != 0)
hcrx->ccid3hcrx_p = 1000000 / i_mean;
} else
DCCP_BUG("empty loss history");
if (hcrx->ccid3hcrx_p > p_prev) {
ccid3_hc_rx_send_feedback(sk);
return;
}
}
static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
ccid3_pr_debug("entry\n");
hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
hcrx->ccid3hcrx_s = 0;
hcrx->ccid3hcrx_rtt = 0;
return 0;
}
static void ccid3_hc_rx_exit(struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
BUG_ON(hcrx == NULL);
ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
/* Empty packet history */
dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
/* Empty loss interval history */
dccp_li_hist_purge(&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 = ccid3_hc_rx_sk(sk);
/* Listen socks doesn't have a private CCID block */
if (sk->sk_state == DCCP_LISTEN)
return;
BUG_ON(hcrx == NULL);
info->tcpi_ca_state = hcrx->ccid3hcrx_state;
info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
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 void *val;
/* Listen socks doesn't have a private CCID block */
if (sk->sk_state == DCCP_LISTEN)
return -EINVAL;
switch (optname) {
case DCCP_SOCKOPT_CCID_RX_INFO:
if (len < sizeof(hcrx->ccid3hcrx_tfrc))
return -EINVAL;
len = sizeof(hcrx->ccid3hcrx_tfrc);
val = &hcrx->ccid3hcrx_tfrc;
break;
default:
return -ENOPROTOOPT;
}
if (put_user(len, optlen) || copy_to_user(optval, val, len))
return -EFAULT;
return 0;
}
static struct ccid_operations ccid3 = {
.ccid_id = DCCPC_CCID3,
.ccid_name = "ccid3",
.ccid_owner = THIS_MODULE,
.ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
.ccid_hc_tx_init = ccid3_hc_tx_init,
.ccid_hc_tx_exit = ccid3_hc_tx_exit,
.ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
.ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
.ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
.ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
.ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
.ccid_hc_rx_init = ccid3_hc_rx_init,
.ccid_hc_rx_exit = ccid3_hc_rx_exit,
.ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
.ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
.ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
.ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
.ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
.ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
};
#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
module_param(ccid3_debug, int, 0444);
MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
#endif
static __init int ccid3_module_init(void)
{
int rc = -ENOBUFS;
ccid3_rx_hist = dccp_rx_hist_new("ccid3");
if (ccid3_rx_hist == NULL)
goto out;
ccid3_tx_hist = dccp_tx_hist_new("ccid3");
if (ccid3_tx_hist == NULL)
goto out_free_rx;
rc = ccid_register(&ccid3);
if (rc != 0)
goto out_free_tx;
out:
return rc;
out_free_tx:
dccp_tx_hist_delete(ccid3_tx_hist);
ccid3_tx_hist = NULL;
out_free_rx:
dccp_rx_hist_delete(ccid3_rx_hist);
ccid3_rx_hist = NULL;
goto out;
}
module_init(ccid3_module_init);
static __exit void ccid3_module_exit(void)
{
ccid_unregister(&ccid3);
if (ccid3_tx_hist != NULL) {
dccp_tx_hist_delete(ccid3_tx_hist);
ccid3_tx_hist = NULL;
}
if (ccid3_rx_hist != NULL) {
dccp_rx_hist_delete(ccid3_rx_hist);
ccid3_rx_hist = NULL;
}
}
module_exit(ccid3_module_exit);
MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
"Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
MODULE_LICENSE("GPL");
MODULE_ALIAS("net-dccp-ccid-3");
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