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de553c189e
linux/net/dccp/ccids/ccid3.c
Gerrit Renker de553c189e [DCCP] ccid3: Sanity-check RTT samples 
CCID3 performance depends much on the accuracy of RTT samples.  If RTT
samples grow too large, performance can be catastrophically poor.

To limit the amount of possible damage in such cases, the patch
 * introduces an upper limit which identifies a maximum `sane' RTT value;
 * uses a macro to enforce this upper limit.

Using a macro was given preference, since it is necessary to identify the
calling function in the warning message. Since exceeding this threshold
identifies a critical condition, DCCP_CRIT is used and not DCCP_WARN.

Many thanks to Ian McDonald for collaboration on this issue.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-11 14:34:51 -08:00

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/*
* net/dccp/ccids/ccid3.c
*
* Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005-6 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;
static struct dccp_li_hist *ccid3_li_hist;
#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;
}
/*
* Recalculate scheduled nominal send time t_nom, inter-packet interval
* t_ipi, and delta value. Should be called after each change to X.
*/
static inline void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx)
{
timeval_sub_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
/* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
hctx->ccid3hctx_t_ipi = scaled_div(hctx->ccid3hctx_s,
hctx->ccid3hctx_x >> 6);
/* Update nominal send time with regard to the new t_ipi */
timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
/* 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);
}
/*
* 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).
*
* If X has changed, we also update the scheduled send time t_now,
* the inter-packet interval t_ipi, and the delta value.
*/
static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
const __u64 old_x = hctx->ccid3hctx_x;
if (hctx->ccid3hctx_p > 0) {
hctx->ccid3hctx_x = min_t(u64, hctx->ccid3hctx_x_calc << 6,
hctx->ccid3hctx_x_recv * 2 );
hctx->ccid3hctx_x = max_t(u64, hctx->ccid3hctx_x,
(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(2 * min(hctx->ccid3hctx_x,
hctx->ccid3hctx_x_recv),
scaled_div(hctx->ccid3hctx_s << 6,
hctx->ccid3hctx_rtt ));
hctx->ccid3hctx_t_ld = *now;
}
if (hctx->ccid3hctx_x != old_x)
ccid3_update_send_time(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)
{
if (unlikely(len == 0))
ccid3_pr_debug("Packet payload length is 0 - not updating\n");
else
hctx->ccid3hctx_s = hctx->ccid3hctx_s == 0 ? len :
(9 * hctx->ccid3hctx_s + len) / 10;
/*
* Note: We could do a potential optimisation here - when `s' changes,
* recalculate sending rate and consequently t_ipi, t_delta, and
* t_now. This is however non-standard, and the benefits are not
* clear, so it is currently left out.
*/
}
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);
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, sk=%p, state=%s\n", dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state));
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_FBACK:
/* RFC 3448, 4.4: Halve send rate directly */
hctx->ccid3hctx_x = max_t(u32, hctx->ccid3hctx_x / 2,
(hctx->ccid3hctx_s << 6)/TFRC_T_MBI);
ccid3_pr_debug("%s, sk=%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_time(hctx);
break;
case TFRC_SSTATE_FBACK:
/*
* Check if IDLE since last timeout and recv rate is less than
* 4 packets (in units of 64*bytes/sec) per RTT
*/
if (!hctx->ccid3hctx_idle ||
(hctx->ccid3hctx_x_recv >= 4 *
scaled_div(hctx->ccid3hctx_s << 6, hctx->ccid3hctx_rtt))) {
struct timeval now;
ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state));
/*
* 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_t(u64, hctx->ccid3hctx_x_recv / 2,
(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 << 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("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
/* fall through */
case TFRC_SSTATE_TERM:
goto out;
}
hctx->ccid3hctx_idle = 1;
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);
struct dccp_tx_hist_entry *new_packet;
struct timeval now;
suseconds_t 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;
/* See if last packet allocated was not sent */
new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
if (new_packet == NULL || new_packet->dccphtx_sent) {
new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
GFP_ATOMIC);
if (unlikely(new_packet == NULL)) {
DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
"send refused\n", dccp_role(sk), sk);
return -ENOBUFS;
}
dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
}
dccp_timestamp(sk, &now);
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;
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
/* Set initial sending rate X/s to 1pps (X is scaled by 2^6) */
ccid3_hc_tx_update_s(hctx, skb->len);
hctx->ccid3hctx_x = hctx->ccid3hctx_s << 6;
/* First timeout, according to [RFC 3448, 4.2], is 1 second */
hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
/* Initial delta: minimum of 0.5 sec and t_gran/2 */
hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
/* Set t_0 for initial packet */
hctx->ccid3hctx_t_nom = now;
break;
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
/*
* 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 - (suseconds_t)hctx->ccid3hctx_delta >= 0)
return delay / 1000L;
break;
case TFRC_SSTATE_TERM:
DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
return -EINVAL;
}
/* prepare to send now (add options etc.) */
dp->dccps_hc_tx_insert_options = 1;
new_packet->dccphtx_ccval = DCCP_SKB_CB(skb)->dccpd_ccval =
hctx->ccid3hctx_last_win_count;
timeval_add_usecs(&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)
{
const struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
struct timeval now;
suseconds_t quarter_rtt;
struct dccp_tx_hist_entry *packet;
BUG_ON(hctx == NULL);
dccp_timestamp(sk, &now);
ccid3_hc_tx_update_s(hctx, len);
packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
if (unlikely(packet == NULL)) {
DCCP_WARN("packet doesn't exist in history!\n");
return;
}
if (unlikely(packet->dccphtx_sent)) {
DCCP_WARN("no unsent packet in history!\n");
return;
}
packet->dccphtx_tstamp = now;
packet->dccphtx_seqno = dp->dccps_gss;
/*
* Check if win_count have changed
* Algorithm in "8.1. Window Counter Value" in RFC 4342.
*/
quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
if (likely(hctx->ccid3hctx_rtt > 8))
quarter_rtt /= hctx->ccid3hctx_rtt / 4;
if (quarter_rtt > 0) {
hctx->ccid3hctx_t_last_win_count = now;
hctx->ccid3hctx_last_win_count = (hctx->ccid3hctx_last_win_count +
min_t(unsigned long, quarter_rtt, 5)) % 16;
ccid3_pr_debug("%s, sk=%p, window changed from "
"%u to %u!\n",
dccp_role(sk), sk,
packet->dccphtx_ccval,
hctx->ccid3hctx_last_win_count);
}
hctx->ccid3hctx_idle = 0;
packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
packet->dccphtx_sent = 1;
}
static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
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;
struct dccp_tx_hist_entry *packet;
struct timeval now;
unsigned long t_nfb;
u32 pinv;
long r_sample, t_elapsed;
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 << 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 = timeval_delta(&now, &packet->dccphtx_tstamp);
t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
DCCP_BUG_ON(r_sample < 0);
if (unlikely(r_sample <= t_elapsed))
DCCP_WARN("WARNING: r_sample=%ldus <= t_elapsed=%ldus\n",
r_sample, t_elapsed);
else
r_sample -= t_elapsed;
CCID3_RTT_SANITY_CHECK(r_sample);
/* 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]
* We deviate in that we use `s' instead of `MSS'.
*/
u16 w_init = min( 4 * hctx->ccid3hctx_s,
max(2 * hctx->ccid3hctx_s, 4380));
hctx->ccid3hctx_rtt = r_sample;
hctx->ccid3hctx_x = scaled_div(w_init<< 6, r_sample);
hctx->ccid3hctx_t_ld = now;
ccid3_update_send_time(hctx);
ccid3_pr_debug("%s(%p), s=%u, w_init=%u, "
"R_sample=%ldus, X=%u\n", dccp_role(sk),
sk, hctx->ccid3hctx_s, w_init, r_sample,
(unsigned)(hctx->ccid3hctx_x >> 6));
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
} else {
hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
(u32)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=%ldus), s=%u, "
"p=%u, X_calc=%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 >> 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, sk=%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:
/* XXX when implementing bidirectional rx/tx check this again */
DCCP_WARN("Illegal ACK received - no packet sent\n");
/* 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, sk=%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, sk=%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, sk=%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, sk=%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, sk=%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);
}
/*
* RX Half Connection methods
*/
#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, sk=%p\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("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
return;
}
packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
if (unlikely(packet == NULL)) {
DCCP_WARN("%s, sk=%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;
}
/* calculate first loss interval
*
* returns estimated loss interval in usecs */
static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
u32 x_recv, p;
suseconds_t rtt, delta;
struct timeval tstamp = { 0, };
int interval = 0;
int win_count = 0;
int step = 0;
u64 fval;
list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
dccphrx_node) {
if (dccp_rx_hist_entry_data_packet(entry)) {
tail = entry;
switch (step) {
case 0:
tstamp = entry->dccphrx_tstamp;
win_count = entry->dccphrx_ccval;
step = 1;
break;
case 1:
interval = win_count - entry->dccphrx_ccval;
if (interval < 0)
interval += TFRC_WIN_COUNT_LIMIT;
if (interval > 4)
goto found;
break;
}
}
}
if (unlikely(step == 0)) {
DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
dccp_role(sk), sk);
return ~0;
}
if (unlikely(interval == 0)) {
DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
"Defaulting to 1\n", dccp_role(sk), sk);
interval = 1;
}
found:
if (!tail) {
DCCP_CRIT("tail is null\n");
return ~0;
}
delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
DCCP_BUG_ON(delta < 0);
rtt = delta * 4 / interval;
ccid3_pr_debug("%s, sk=%p, approximated RTT to %ldus\n",
dccp_role(sk), sk, rtt);
/*
* Determine the length of the first loss interval via inverse lookup.
* Assume that X_recv can be computed by the throughput equation
* s
* X_recv = --------
* R * fval
* Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
*/
if (rtt == 0) { /* would result in divide-by-zero */
DCCP_WARN("RTT==0, returning 1/p = 1\n");
return 1000000;
}
dccp_timestamp(sk, &tstamp);
delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
DCCP_BUG_ON(delta <= 0);
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 1000000;
}
}
fval = scaled_div(hcrx->ccid3hcrx_s, rtt);
fval = scaled_div32(fval, x_recv);
p = tfrc_calc_x_reverse_lookup(fval);
ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
"loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
if (p == 0)
return ~0;
else
return 1000000 / p;
}
static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
struct dccp_li_hist_entry *head;
u64 seq_temp;
if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
if (!dccp_li_hist_interval_new(ccid3_li_hist,
&hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
return;
head = list_entry(hcrx->ccid3hcrx_li_hist.next,
struct dccp_li_hist_entry, dccplih_node);
head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
} else {
struct dccp_li_hist_entry *entry;
struct list_head *tail;
head = list_entry(hcrx->ccid3hcrx_li_hist.next,
struct dccp_li_hist_entry, dccplih_node);
/* FIXME win count check removed as was wrong */
/* should make this check with receive history */
/* and compare there as per section 10.2 of RFC4342 */
/* new loss event detected */
/* calculate last interval length */
seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
if (entry == NULL) {
DCCP_BUG("out of memory - can not allocate entry");
return;
}
list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
tail = hcrx->ccid3hcrx_li_hist.prev;
list_del(tail);
kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
/* Create the newest interval */
entry->dccplih_seqno = seq_loss;
entry->dccplih_interval = seq_temp;
entry->dccplih_win_count = win_loss;
}
}
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;
ccid3_hc_rx_update_li(sk, 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, rtt_prev;
suseconds_t r_sample, t_elapsed;
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);
timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
r_sample = timeval_usecs(&now);
t_elapsed = opt_recv->dccpor_elapsed_time * 10;
DCCP_BUG_ON(r_sample < 0);
if (unlikely(r_sample <= t_elapsed))
DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
r_sample, t_elapsed);
else
r_sample -= t_elapsed;
CCID3_RTT_SANITY_CHECK(r_sample);
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, New RTT=%uus, elapsed time=%u\n",
dccp_role(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, sk=%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, sk=%p(%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("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
return;
}
/* Dealing with packet loss */
ccid3_pr_debug("%s, sk=%p(%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("%s, sk=%p\n", dccp_role(sk), sk);
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(ccid3_li_hist, &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 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_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 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;
}
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;
ccid3_li_hist = dccp_li_hist_new("ccid3");
if (ccid3_li_hist == NULL)
goto out_free_tx;
rc = ccid_register(&ccid3);
if (rc != 0)
goto out_free_loss_interval_history;
out:
return rc;
out_free_loss_interval_history:
dccp_li_hist_delete(ccid3_li_hist);
ccid3_li_hist = NULL;
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;
}
if (ccid3_li_hist != NULL) {
dccp_li_hist_delete(ccid3_li_hist);
ccid3_li_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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