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gerrit-public.fairphone.software / kernel / msm-4.19 / 88f964db6ef728982734356bf4c406270ea29c1d / . / net / dccp / ccids / ccid3.c
blob: aa68e0ab274d4b837a8147b6cb4d677d53740185 [file] [log] [blame]
/*
* net/dccp/ccids/ccid3.c
*
* Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.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 <linux/config.h>
#include "../ccid.h"
#include "../dccp.h"
#include "lib/packet_history.h"
#include "lib/loss_interval.h"
#include "lib/tfrc.h"
#include "ccid3.h"
/*
* Reason for maths here is to avoid 32 bit overflow when a is big.
* With this we get close to the limit.
*/
static inline u32 usecs_div(const u32 a, const u32 b)
{
const u32 div = a < (UINT_MAX / (USEC_PER_SEC / 10)) ? 10 :
a < (UINT_MAX / (USEC_PER_SEC / 50)) ? 50 :
a < (UINT_MAX / (USEC_PER_SEC / 100)) ? 100 :
a < (UINT_MAX / (USEC_PER_SEC / 500)) ? 500 :
a < (UINT_MAX / (USEC_PER_SEC / 1000)) ? 1000 :
a < (UINT_MAX / (USEC_PER_SEC / 5000)) ? 5000 :
a < (UINT_MAX / (USEC_PER_SEC / 10000)) ? 10000 :
a < (UINT_MAX / (USEC_PER_SEC / 50000)) ? 50000 :
100000;
const u32 tmp = a * (USEC_PER_SEC / div);
return (b >= 2 * div) ? tmp / (b / div) : tmp;
}
static int ccid3_debug;
#ifdef CCID3_DEBUG
#define ccid3_pr_debug(format, a...) \
do { if (ccid3_debug) \
printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \
} while (0)
#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;
static int ccid3_init(struct sock *sk)
{
return 0;
}
static void ccid3_exit(struct sock *sk)
{
}
/* TFRC sender states */
enum ccid3_hc_tx_states {
TFRC_SSTATE_NO_SENT = 1,
TFRC_SSTATE_NO_FBACK,
TFRC_SSTATE_FBACK,
TFRC_SSTATE_TERM,
};
#ifdef 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 inline 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;
}
/* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
static inline void ccid3_calc_new_t_ipi(struct ccid3_hc_tx_sock *hctx)
{
/*
* If no feedback spec says t_ipi is 1 second (set elsewhere and then
* doubles after every no feedback timer (separate function)
*/
if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s,
hctx->ccid3hctx_x);
}
/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
static inline void ccid3_calc_new_delta(struct ccid3_hc_tx_sock *hctx)
{
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;
*/
static void ccid3_hc_tx_update_x(struct sock *sk)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
/* To avoid large error in calcX */
if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
hctx->ccid3hctx_rtt,
hctx->ccid3hctx_p);
hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc,
2 * hctx->ccid3hctx_x_recv),
(hctx->ccid3hctx_s /
TFRC_MAX_BACK_OFF_TIME));
} else {
struct timeval now;
dccp_timestamp(sk, &now);
if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >=
hctx->ccid3hctx_rtt) {
hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_recv,
hctx->ccid3hctx_x) * 2,
usecs_div(hctx->ccid3hctx_s,
hctx->ccid3hctx_rtt));
hctx->ccid3hctx_t_ld = now;
}
}
}
static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
{
struct sock *sk = (struct sock *)data;
unsigned long next_tmout = 0;
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) {
/* Try again later. */
/* XXX: set some sensible MIB */
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + HZ / 5);
goto out;
}
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_TERM:
goto out;
case TFRC_SSTATE_NO_FBACK:
/* Halve send rate */
hctx->ccid3hctx_x /= 2;
if (hctx->ccid3hctx_x < (hctx->ccid3hctx_s /
TFRC_MAX_BACK_OFF_TIME))
hctx->ccid3hctx_x = (hctx->ccid3hctx_s /
TFRC_MAX_BACK_OFF_TIME);
ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d "
"bytes/s\n",
dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state),
hctx->ccid3hctx_x);
next_tmout = max_t(u32, 2 * usecs_div(hctx->ccid3hctx_s,
hctx->ccid3hctx_x),
TFRC_INITIAL_TIMEOUT);
/*
* FIXME - not sure above calculation is correct. See section
* 5 of CCID3 11 should adjust tx_t_ipi and double that to
* achieve it really
*/
break;
case TFRC_SSTATE_FBACK:
/*
* Check if IDLE since last timeout and recv rate is less than
* 4 packets per RTT
*/
if (!hctx->ccid3hctx_idle ||
(hctx->ccid3hctx_x_recv >=
4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) {
ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state));
/* Halve sending rate */
/* If (X_calc > 2 * X_recv)
* X_recv = max(X_recv / 2, s / (2 * t_mbi));
* Else
* X_recv = X_calc / 4;
*/
BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P &&
hctx->ccid3hctx_x_calc == 0);
/* check also if p is zero -> x_calc is infinity? */
if (hctx->ccid3hctx_p < TFRC_SMALLEST_P ||
hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv)
hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
hctx->ccid3hctx_s / (2 * TFRC_MAX_BACK_OFF_TIME));
else
hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4;
/* Update sending rate */
ccid3_hc_tx_update_x(sk);
}
/*
* Schedule no feedback timer to expire in
* max(4 * R, 2 * s / X)
*/
next_tmout = max_t(u32, hctx->ccid3hctx_t_rto,
2 * usecs_div(hctx->ccid3hctx_s,
hctx->ccid3hctx_x));
break;
default:
printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
__FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
dump_stack();
goto out;
}
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
hctx->ccid3hctx_idle = 1;
out:
bh_unlock_sock(sk);
sock_put(sk);
}
static int ccid3_hc_tx_send_packet(struct sock *sk,
struct sk_buff *skb, int len)
{
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;
long delay;
int rc = -ENOTCONN;
BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
/* Check if pure ACK or Terminating*/
/*
* XXX: We only call this function for DATA and DATAACK, on, these
* packets can have zero length, but why the comment about "pure ACK"?
*/
if (unlikely(len == 0))
goto out;
/* 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,
SLAB_ATOMIC);
rc = -ENOBUFS;
if (unlikely(new_packet == NULL)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, not enough "
"mem to add to history, send refused\n",
__FUNCTION__, dccp_role(sk), sk);
goto out;
}
dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
}
dccp_timestamp(sk, &now);
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_SENT:
hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
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);
hctx->ccid3hctx_t_ipi = TFRC_INITIAL_IPI;
/* Set nominal send time for initial packet */
hctx->ccid3hctx_t_nom = now;
timeval_add_usecs(&hctx->ccid3hctx_t_nom,
hctx->ccid3hctx_t_ipi);
ccid3_calc_new_delta(hctx);
rc = 0;
break;
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
delay = (timeval_delta(&now, &hctx->ccid3hctx_t_nom) -
hctx->ccid3hctx_delta);
delay /= -1000;
/* divide by -1000 is to convert to ms and get sign right */
rc = delay > 0 ? delay : 0;
break;
default:
printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
__FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
dump_stack();
rc = -EINVAL;
break;
}
/* Can we send? if so add options and add to packet history */
if (rc == 0) {
dp->dccps_hc_tx_insert_options = 1;
new_packet->dccphtx_ccval =
DCCP_SKB_CB(skb)->dccpd_ccval =
hctx->ccid3hctx_last_win_count;
}
out:
return rc;
}
static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
{
const struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
struct timeval now;
BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
dccp_timestamp(sk, &now);
/* check if we have sent a data packet */
if (len > 0) {
unsigned long quarter_rtt;
struct dccp_tx_hist_entry *packet;
packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
if (unlikely(packet == NULL)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: packet doesn't "
"exists in history!\n", __FUNCTION__);
return;
}
if (unlikely(packet->dccphtx_sent)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: no unsent packet in "
"history!\n", __FUNCTION__);
return;
}
packet->dccphtx_tstamp = now;
packet->dccphtx_seqno = dp->dccps_gss;
/*
* Check if win_count have changed
* Algorithm in "8.1. Window Counter Valuer" in
* draft-ietf-dccp-ccid3-11.txt
*/
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;
} else
ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n",
dccp_role(sk), sk, dp->dccps_gss);
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_SENT:
/* if first wasn't pure ack */
if (len != 0)
printk(KERN_CRIT "%s: %s, First packet sent is noted "
"as a data packet\n",
__FUNCTION__, dccp_role(sk));
return;
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
if (len > 0) {
hctx->ccid3hctx_t_nom = now;
ccid3_calc_new_t_ipi(hctx);
ccid3_calc_new_delta(hctx);
timeval_add_usecs(&hctx->ccid3hctx_t_nom,
hctx->ccid3hctx_t_ipi);
}
break;
default:
printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
__FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
dump_stack();
break;
}
}
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 next_tmout;
u32 t_elapsed;
u32 pinv;
u32 x_recv;
u32 r_sample;
BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
/* 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;
t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
x_recv = opt_recv->ccid3or_receive_rate;
pinv = opt_recv->ccid3or_loss_event_rate;
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_SENT:
/* FIXME: what to do here? */
return;
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
/* Calculate new round trip sample by
* R_sample = (now - t_recvdata) - t_delay */
/* get t_recvdata from history */
packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
DCCP_SKB_CB(skb)->dccpd_ack_seq);
if (unlikely(packet == NULL)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, seqno "
"%llu(%s) does't exist in history!\n",
__FUNCTION__, 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 RTT */
dccp_timestamp(sk, &now);
r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
if (unlikely(r_sample <= t_elapsed))
LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
"t_elapsed=%uus\n",
__FUNCTION__, r_sample, t_elapsed);
else
r_sample -= t_elapsed;
/* 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) {
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
hctx->ccid3hctx_rtt = r_sample;
} else
hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
r_sample / 10;
ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
"r_sample=%us\n", dccp_role(sk), sk,
hctx->ccid3hctx_rtt, r_sample);
/* Update timeout interval */
hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
USEC_PER_SEC);
/* Update receive rate */
hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
/* Update loss event rate */
if (pinv == ~0 || pinv == 0)
hctx->ccid3hctx_p = 0;
else {
hctx->ccid3hctx_p = 1000000 / pinv;
if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
hctx->ccid3hctx_p = TFRC_SMALLEST_P;
ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
dccp_role(sk), sk);
}
}
/* unschedule no feedback timer */
sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
/* Update sending rate */
ccid3_hc_tx_update_x(sk);
/* Update next send time */
timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
hctx->ccid3hctx_t_ipi);
ccid3_calc_new_t_ipi(hctx);
timeval_add_usecs(&hctx->ccid3hctx_t_nom,
hctx->ccid3hctx_t_ipi);
ccid3_calc_new_delta(hctx);
/* 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_ccids.
*/
sk->sk_write_space(sk);
/*
* Schedule no feedback timer to expire in
* max(4 * R, 2 * s / X)
*/
next_tmout = max(hctx->ccid3hctx_t_rto,
2 * usecs_div(hctx->ccid3hctx_s,
hctx->ccid3hctx_x));
ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
"expire in %lu jiffies (%luus)\n",
dccp_role(sk), sk,
usecs_to_jiffies(next_tmout), next_tmout);
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
/* set idle flag */
hctx->ccid3hctx_idle = 1;
break;
default:
printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
__FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
dump_stack();
break;
}
}
static void ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
{
const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
BUG_ON(hctx == NULL);
if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
return;
DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
}
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)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
"len for TFRC_OPT_LOSS_EVENT_RATE\n",
__FUNCTION__, dccp_role(sk), sk);
rc = -EINVAL;
} else {
opt_recv->ccid3or_loss_event_rate = ntohl(*(u32 *)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)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
"len for TFRC_OPT_RECEIVE_RATE\n",
__FUNCTION__, dccp_role(sk), sk);
rc = -EINVAL;
} else {
opt_recv->ccid3or_receive_rate = ntohl(*(u32 *)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 sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hctx;
dp->dccps_hc_tx_ccid_private = kmalloc(sizeof(*hctx), gfp_any());
if (dp->dccps_hc_tx_ccid_private == NULL)
return -ENOMEM;
hctx = ccid3_hc_tx_sk(sk);
memset(hctx, 0, sizeof(*hctx));
if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
hctx->ccid3hctx_s = dp->dccps_packet_size;
else
hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;
/* Set transmission rate to 1 packet per second */
hctx->ccid3hctx_x = hctx->ccid3hctx_s;
hctx->ccid3hctx_t_rto = USEC_PER_SEC;
hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
init_timer(&hctx->ccid3hctx_no_feedback_timer);
return 0;
}
static void ccid3_hc_tx_exit(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(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);
kfree(dp->dccps_hc_tx_ccid_private);
dp->dccps_hc_tx_ccid_private = NULL;
}
/*
* RX Half Connection methods
*/
/* TFRC receiver states */
enum ccid3_hc_rx_states {
TFRC_RSTATE_NO_DATA = 1,
TFRC_RSTATE_DATA,
TFRC_RSTATE_TERM = 127,
};
#ifdef 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 inline 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)
{
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;
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: {
const u32 delta = timeval_delta(&now,
&hcrx->ccid3hcrx_tstamp_last_feedback);
hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
delta);
}
break;
default:
printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
__FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
dump_stack();
return;
}
packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
if (unlikely(packet == NULL)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, no data packet "
"in history!\n",
__FUNCTION__, dccp_role(sk), sk);
return;
}
hcrx->ccid3hcrx_tstamp_last_feedback = now;
hcrx->ccid3hcrx_last_counter = packet->dccphrx_ccval;
hcrx->ccid3hcrx_seqno_last_counter = packet->dccphrx_seqno;
hcrx->ccid3hcrx_bytes_recv = 0;
/* Convert to multiples of 10us */
hcrx->ccid3hcrx_elapsed_time =
timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
if (hcrx->ccid3hcrx_p == 0)
hcrx->ccid3hcrx_pinv = ~0;
else
hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
dp->dccps_hc_rx_insert_options = 1;
dccp_send_ack(sk);
}
static void ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
{
const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
u32 x_recv, pinv;
BUG_ON(hcrx == NULL);
if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
return;
DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_last_counter;
if (dccp_packet_without_ack(skb))
return;
if (hcrx->ccid3hcrx_elapsed_time != 0)
dccp_insert_option_elapsed_time(sk, skb,
hcrx->ccid3hcrx_elapsed_time);
dccp_insert_option_timestamp(sk, skb);
x_recv = htonl(hcrx->ccid3hcrx_x_recv);
pinv = htonl(hcrx->ccid3hcrx_pinv);
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));
}
/* 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 rtt, delta, x_recv, fval, p, tmp2;
struct timeval tstamp = { 0, };
int interval = 0;
int win_count = 0;
int step = 0;
u64 tmp1;
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)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, packet history "
"contains no data packets!\n",
__FUNCTION__, dccp_role(sk), sk);
return ~0;
}
if (unlikely(interval == 0)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Could not find a "
"win_count interval > 0. Defaulting to 1\n",
__FUNCTION__, dccp_role(sk), sk);
interval = 1;
}
found:
rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
dccp_role(sk), sk, rtt);
if (rtt == 0)
rtt = 1;
dccp_timestamp(sk, &tstamp);
delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
tmp1 = (u64)x_recv * (u64)rtt;
do_div(tmp1,10000000);
tmp2 = (u32)tmp1;
fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
/* do not alter order above or you will get overflow on 32 bit */
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);
if (seq_loss != DCCP_MAX_SEQNO + 1 &&
list_empty(&hcrx->ccid3hcrx_li_hist)) {
struct dccp_li_hist_entry *li_tail;
li_tail = dccp_li_hist_interval_new(ccid3_li_hist,
&hcrx->ccid3hcrx_li_hist,
seq_loss, win_loss);
if (li_tail == NULL)
return;
li_tail->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
} else
LIMIT_NETDEBUG(KERN_WARNING "%s: FIXME: find end of "
"interval\n", __FUNCTION__);
}
static void ccid3_hc_rx_detect_loss(struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
u8 win_loss;
const u64 seq_loss = dccp_rx_hist_detect_loss(&hcrx->ccid3hcrx_hist,
&hcrx->ccid3hcrx_li_hist,
&win_loss);
ccid3_hc_rx_update_li(sk, seq_loss, win_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;
u8 win_count;
u32 p_prev, r_sample, t_elapsed;
int ins;
BUG_ON(hcrx == NULL ||
!(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA ||
hcrx->ccid3hcrx_state == TFRC_RSTATE_DATA));
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;
p_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;
if (unlikely(r_sample <= t_elapsed))
LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
"t_elapsed=%uus\n",
__FUNCTION__, r_sample, t_elapsed);
else
r_sample -= t_elapsed;
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 (p_prev != hcrx->ccid3hcrx_rtt)
ccid3_pr_debug("%s, New RTT=%luus, 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, SLAB_ATOMIC);
if (unlikely(packet == NULL)) {
LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Not enough mem to "
"add rx packet to history, consider it lost!\n",
__FUNCTION__, dccp_role(sk), sk);
return;
}
win_count = packet->dccphrx_ccval;
ins = dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
&hcrx->ccid3hcrx_li_hist, packet);
if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
return;
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 += skb->len -
dccp_hdr(skb)->dccph_doff * 4;
if (ins != 0)
break;
dccp_timestamp(sk, &now);
if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
hcrx->ccid3hcrx_rtt) {
hcrx->ccid3hcrx_tstamp_last_ack = now;
ccid3_hc_rx_send_feedback(sk);
}
return;
default:
printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
__FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
dump_stack();
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));
ccid3_hc_rx_detect_loss(sk);
p_prev = hcrx->ccid3hcrx_p;
/* Calculate loss event rate */
if (!list_empty(&hcrx->ccid3hcrx_li_hist))
/* Scaling up by 1000000 as fixed decimal */
hcrx->ccid3hcrx_p = 1000000 / dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
if (hcrx->ccid3hcrx_p > p_prev) {
ccid3_hc_rx_send_feedback(sk);
return;
}
}
static int ccid3_hc_rx_init(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_rx_sock *hcrx;
ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
dp->dccps_hc_rx_ccid_private = kmalloc(sizeof(*hcrx), gfp_any());
if (dp->dccps_hc_rx_ccid_private == NULL)
return -ENOMEM;
hcrx = ccid3_hc_rx_sk(sk);
memset(hcrx, 0, sizeof(*hcrx));
if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
hcrx->ccid3hcrx_s = dp->dccps_packet_size;
else
hcrx->ccid3hcrx_s = TFRC_STD_PACKET_SIZE;
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_rtt = 5000; /* XXX 5ms for now... */
return 0;
}
static void ccid3_hc_rx_exit(struct sock *sk)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
struct dccp_sock *dp = dccp_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);
kfree(dp->dccps_hc_rx_ccid_private);
dp->dccps_hc_rx_ccid_private = NULL;
}
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 ccid3 = {
.ccid_id = 3,
.ccid_name = "ccid3",
.ccid_owner = THIS_MODULE,
.ccid_init = ccid3_init,
.ccid_exit = ccid3_exit,
.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_insert_options = ccid3_hc_tx_insert_options,
.ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
.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,
};
module_param(ccid3_debug, int, 0444);
MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
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)
{
#ifdef CONFIG_IP_DCCP_UNLOAD_HACK
/*
* Hack to use while developing, so that we get rid of the control
* sock, that is what keeps a refcount on dccp.ko -acme
*/
extern void dccp_ctl_sock_exit(void);
dccp_ctl_sock_exit();
#endif
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 <iam4@cs.waikato.ac.nz>, "
"Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
MODULE_LICENSE("GPL");
MODULE_ALIAS("net-dccp-ccid-3");