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[DCCP] CCID2: Initial CCID2 (TCP-Like) implementation

Browse source 
Original work by Andrea Bittau, Arnaldo Melo cleaned up and fixed several
issues on the merge process.

For now CCID2 was turned the default for all SOCK_DCCP connections, but this
will be remedied soon with the merge of the feature negotiation code.

Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andrea Bittau 2006-03-20 17:41:47 -08:00 committed by David S. Miller
parent aa5d7df3b2
commit 2a91aa3967
7 changed files with 957 additions and 6 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

8
include/linux/dccp.h
View file

@ -314,9 +314,9 @@ static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
/* initial values for each feature */
#define DCCPF_INITIAL_SEQUENCE_WINDOW 100
/* FIXME: for now we're using CCID 3 (TFRC) */
#define DCCPF_INITIAL_CCID 3
#define DCCPF_INITIAL_SEND_ACK_VECTOR 0
/* FIXME: for now we're using CCID 2 (TCP-Like) */
#define DCCPF_INITIAL_CCID 2
#define DCCPF_INITIAL_SEND_ACK_VECTOR 1
/* FIXME: for now we're default to 1 but it should really be 0 */
#define DCCPF_INITIAL_SEND_NDP_COUNT 1
@ -430,6 +430,8 @@ struct dccp_sock {
struct timeval dccps_timestamp_time;
__u32 dccps_timestamp_echo;
__u32 dccps_packet_size;
__u16 dccps_l_ack_ratio;
__u16 dccps_r_ack_ratio;
unsigned long dccps_ndp_count;
__u32 dccps_mss_cache;
struct dccp_options dccps_options;

4
net/dccp/Kconfig
View file

@ -24,6 +24,10 @@ config INET_DCCP_DIAG
def_tristate y if (IP_DCCP = y && INET_DIAG = y)
def_tristate m
config IP_DCCP_ACKVEC
depends on IP_DCCP
def_bool N
source "net/dccp/ccids/Kconfig"
menu "DCCP Kernel Hacking"

39
net/dccp/ccids/Kconfig
View file

@ -1,6 +1,34 @@
menu "DCCP CCIDs Configuration (EXPERIMENTAL)"
depends on IP_DCCP && EXPERIMENTAL
config IP_DCCP_CCID2
tristate "CCID2 (TCP) (EXPERIMENTAL)"
depends on IP_DCCP
select IP_DCCP_ACKVEC
---help---
CCID 2, TCP-like Congestion Control, denotes Additive Increase,
Multiplicative Decrease (AIMD) congestion control with behavior
modelled directly on TCP, including congestion window, slow start,
timeouts, and so forth [RFC 2581]. CCID 2 achieves maximum
bandwidth over the long term, consistent with the use of end-to-end
congestion control, but halves its congestion window in response to
each congestion event. This leads to the abrupt rate changes
typical of TCP. Applications should use CCID 2 if they prefer
maximum bandwidth utilization to steadiness of rate. This is often
the case for applications that are not playing their data directly
to the user. For example, a hypothetical application that
transferred files over DCCP, using application-level retransmissions
for lost packets, would prefer CCID 2 to CCID 3. On-line games may
also prefer CCID 2.
CCID 2 is further described in:
http://www.icir.org/kohler/dccp/draft-ietf-dccp-ccid2-10.txt
This text was extracted from:
http://www.icir.org/kohler/dccp/draft-ietf-dccp-spec-13.txt
If in doubt, say M.
config IP_DCCP_CCID3
tristate "CCID3 (TFRC) (EXPERIMENTAL)"
depends on IP_DCCP
@ -15,10 +43,15 @@ config IP_DCCP_CCID3
suitable than CCID 2 for applications such streaming media where a
relatively smooth sending rate is of importance.
CCID 3 is further described in [CCID 3 PROFILE]. The TFRC
congestion control algorithms were initially described in RFC 3448.
CCID 3 is further described in:
This text was extracted from draft-ietf-dccp-spec-11.txt.
http://www.icir.org/kohler/dccp/draft-ietf-dccp-ccid3-11.txt.
The TFRC congestion control algorithms were initially described in
RFC 3448.
This text was extracted from:
http://www.icir.org/kohler/dccp/draft-ietf-dccp-spec-13.txt
If in doubt, say M.

4
net/dccp/ccids/Makefile
View file

@ -2,4 +2,8 @@ obj-$(CONFIG_IP_DCCP_CCID3) += dccp_ccid3.o
dccp_ccid3-y := ccid3.o
obj-$(CONFIG_IP_DCCP_CCID2) += dccp_ccid2.o
dccp_ccid2-y := ccid2.o
obj-y += lib/

838
net/dccp/ccids/ccid2.c Normal file
View file

@ -0,0 +1,838 @@
/*
* net/dccp/ccids/ccid2.c
*
* Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
*
* Changes to meet Linux coding standards, and DCCP infrastructure fixes.
*
* Copyright (c) 2006 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.
*/
/*
* This implementation should follow: draft-ietf-dccp-ccid2-10.txt
*
* BUGS:
* - sequence number wrapping
* - jiffies wrapping
*/
#include <linux/config.h>
#include "../ccid.h"
#include "../dccp.h"
#include "ccid2.h"
static int ccid2_debug;
#if 0
#define CCID2_DEBUG
#endif
#ifdef CCID2_DEBUG
#define ccid2_pr_debug(format, a...) \
do { if (ccid2_debug) \
printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \
} while (0)
#else
#define ccid2_pr_debug(format, a...)
#endif
static const int ccid2_seq_len = 128;
static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
{
return dccp_sk(sk)->dccps_hc_tx_ccid_private;
}
static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
{
return dccp_sk(sk)->dccps_hc_rx_ccid_private;
}
#ifdef CCID2_DEBUG
static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
{
int len = 0;
struct ccid2_seq *seqp;
int pipe = 0;
seqp = hctx->ccid2hctx_seqh;
/* there is data in the chain */
if (seqp != hctx->ccid2hctx_seqt) {
seqp = seqp->ccid2s_prev;
len++;
if (!seqp->ccid2s_acked)
pipe++;
while (seqp != hctx->ccid2hctx_seqt) {
struct ccid2_seq *prev;
prev = seqp->ccid2s_prev;
len++;
if (!prev->ccid2s_acked)
pipe++;
/* packets are sent sequentially */
BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq);
BUG_ON(seqp->ccid2s_sent < prev->ccid2s_sent);
BUG_ON(len > ccid2_seq_len);
seqp = prev;
}
}
BUG_ON(pipe != hctx->ccid2hctx_pipe);
ccid2_pr_debug("len of chain=%d\n", len);
do {
seqp = seqp->ccid2s_prev;
len++;
BUG_ON(len > ccid2_seq_len);
} while(seqp != hctx->ccid2hctx_seqh);
BUG_ON(len != ccid2_seq_len);
ccid2_pr_debug("total len=%d\n", len);
}
#else
#define ccid2_hc_tx_check_sanity(hctx) do {} while (0)
#endif
static int ccid2_hc_tx_send_packet(struct sock *sk,
struct sk_buff *skb, int len)
{
struct ccid2_hc_tx_sock *hctx;
switch (DCCP_SKB_CB(skb)->dccpd_type) {
case 0: /* XXX data packets from userland come through like this */
case DCCP_PKT_DATA:
case DCCP_PKT_DATAACK:
break;
/* No congestion control on other packets */
default:
return 0;
}
hctx = ccid2_hc_tx_sk(sk);
ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe,
hctx->ccid2hctx_cwnd);
if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) {
/* OK we can send... make sure previous packet was sent off */
if (!hctx->ccid2hctx_sendwait) {
hctx->ccid2hctx_sendwait = 1;
return 0;
}
}
return 100; /* XXX */
}
static void ccid2_change_l_ack_ratio(struct sock *sk, int val)
{
struct dccp_sock *dp = dccp_sk(sk);
/*
* XXX I don't really agree with val != 2. If cwnd is 1, ack ratio
* should be 1... it shouldn't be allowed to become 2.
* -sorbo.
*/
if (val != 2) {
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
int max = hctx->ccid2hctx_cwnd / 2;
/* round up */
if (hctx->ccid2hctx_cwnd & 1)
max++;
if (val > max)
val = max;
}
ccid2_pr_debug("changing local ack ratio to %d\n", val);
WARN_ON(val <= 0);
dp->dccps_l_ack_ratio = val;
}
static void ccid2_change_cwnd(struct sock *sk, int val)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
if (val == 0)
val = 1;
/* XXX do we need to change ack ratio? */
ccid2_pr_debug("change cwnd to %d\n", val);
BUG_ON(val < 1);
hctx->ccid2hctx_cwnd = val;
}
static void ccid2_start_rto_timer(struct sock *sk);
static void ccid2_hc_tx_rto_expire(unsigned long data)
{
struct sock *sk = (struct sock *)data;
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
long s;
/* XXX I don't think i'm locking correctly
* -sorbo.
*/
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) {
sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
jiffies + HZ / 5);
goto out;
}
ccid2_pr_debug("RTO_EXPIRE\n");
ccid2_hc_tx_check_sanity(hctx);
/* back-off timer */
hctx->ccid2hctx_rto <<= 1;
s = hctx->ccid2hctx_rto / HZ;
if (s > 60)
hctx->ccid2hctx_rto = 60 * HZ;
ccid2_start_rto_timer(sk);
/* adjust pipe, cwnd etc */
hctx->ccid2hctx_pipe = 0;
hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
if (hctx->ccid2hctx_ssthresh < 2)
hctx->ccid2hctx_ssthresh = 2;
ccid2_change_cwnd(sk, 1);
/* clear state about stuff we sent */
hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
hctx->ccid2hctx_ssacks = 0;
hctx->ccid2hctx_acks = 0;
hctx->ccid2hctx_sent = 0;
/* clear ack ratio state. */
hctx->ccid2hctx_arsent = 0;
hctx->ccid2hctx_ackloss = 0;
hctx->ccid2hctx_rpseq = 0;
hctx->ccid2hctx_rpdupack = -1;
ccid2_change_l_ack_ratio(sk, 1);
ccid2_hc_tx_check_sanity(hctx);
out:
bh_unlock_sock(sk);
/* sock_put(sk); */
}
static void ccid2_start_rto_timer(struct sock *sk)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
jiffies + hctx->ccid2hctx_rto);
}
static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
u64 seq;
ccid2_hc_tx_check_sanity(hctx);
BUG_ON(!hctx->ccid2hctx_sendwait);
hctx->ccid2hctx_sendwait = 0;
hctx->ccid2hctx_pipe++;
BUG_ON(hctx->ccid2hctx_pipe < 0);
/* There is an issue. What if another packet is sent between
* packet_send() and packet_sent(). Then the sequence number would be
* wrong.
* -sorbo.
*/
seq = dp->dccps_gss;
hctx->ccid2hctx_seqh->ccid2s_seq = seq;
hctx->ccid2hctx_seqh->ccid2s_acked = 0;
hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqh->ccid2s_next;
ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
hctx->ccid2hctx_pipe);
if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) {
/* XXX allocate more space */
WARN_ON(1);
}
hctx->ccid2hctx_sent++;
/* Ack Ratio. Need to maintain a concept of how many windows we sent */
hctx->ccid2hctx_arsent++;
/* We had an ack loss in this window... */
if (hctx->ccid2hctx_ackloss) {
if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
hctx->ccid2hctx_arsent = 0;
hctx->ccid2hctx_ackloss = 0;
}
}
/* No acks lost up to now... */
else {
/* decrease ack ratio if enough packets were sent */
if (dp->dccps_l_ack_ratio > 1) {
/* XXX don't calculate denominator each time */
int denom;
denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
dp->dccps_l_ack_ratio;
denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
if (hctx->ccid2hctx_arsent >= denom) {
ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
hctx->ccid2hctx_arsent = 0;
}
}
/* we can't increase ack ratio further [1] */
else {
hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
}
}
/* setup RTO timer */
if (!timer_pending(&hctx->ccid2hctx_rtotimer)) {
ccid2_start_rto_timer(sk);
}
#ifdef CCID2_DEBUG
ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
ccid2_pr_debug("Sent: seq=%llu\n", seq);
do {
struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
while (seqp != hctx->ccid2hctx_seqh) {
ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
seqp->ccid2s_seq, seqp->ccid2s_acked,
seqp->ccid2s_sent);
seqp = seqp->ccid2s_next;
}
} while(0);
ccid2_pr_debug("=========\n");
ccid2_hc_tx_check_sanity(hctx);
#endif
}
/* XXX Lame code duplication!
* returns -1 if none was found.
* else returns the next offset to use in the function call.
*/
static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
unsigned char **vec, unsigned char *veclen)
{
const struct dccp_hdr *dh = dccp_hdr(skb);
unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
unsigned char *opt_ptr;
const unsigned char *opt_end = (unsigned char *)dh +
(dh->dccph_doff * 4);
unsigned char opt, len;
unsigned char *value;
BUG_ON(offset < 0);
options += offset;
opt_ptr = options;
if (opt_ptr >= opt_end)
return -1;
while (opt_ptr != opt_end) {
opt = *opt_ptr++;
len = 0;
value = NULL;
/* Check if this isn't a single byte option */
if (opt > DCCPO_MAX_RESERVED) {
if (opt_ptr == opt_end)
goto out_invalid_option;
len = *opt_ptr++;
if (len < 3)
goto out_invalid_option;
/*
* Remove the type and len fields, leaving
* just the value size
*/
len -= 2;
value = opt_ptr;
opt_ptr += len;
if (opt_ptr > opt_end)
goto out_invalid_option;
}
switch (opt) {
case DCCPO_ACK_VECTOR_0:
case DCCPO_ACK_VECTOR_1:
*vec = value;
*veclen = len;
return offset + (opt_ptr - options);
break;
}
}
return -1;
out_invalid_option:
BUG_ON(1); /* should never happen... options were previously parsed ! */
return -1;
}
static void ccid2_hc_tx_kill_rto_timer(struct ccid2_hc_tx_sock *hctx)
{
if (del_timer(&hctx->ccid2hctx_rtotimer))
ccid2_pr_debug("deleted RTO timer\n");
}
static inline void ccid2_new_ack(struct sock *sk,
struct ccid2_seq *seqp,
unsigned int *maxincr)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
/* slow start */
if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
hctx->ccid2hctx_acks = 0;
/* We can increase cwnd at most maxincr [ack_ratio/2] */
if (*maxincr) {
/* increase every 2 acks */
hctx->ccid2hctx_ssacks++;
if (hctx->ccid2hctx_ssacks == 2) {
ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1);
hctx->ccid2hctx_ssacks = 0;
*maxincr = *maxincr - 1;
}
}
/* increased cwnd enough for this single ack */
else {
hctx->ccid2hctx_ssacks = 0;
}
}
else {
hctx->ccid2hctx_ssacks = 0;
hctx->ccid2hctx_acks++;
if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1);
hctx->ccid2hctx_acks = 0;
}
}
/* update RTO */
if (hctx->ccid2hctx_srtt == -1 ||
(jiffies - hctx->ccid2hctx_lastrtt) >= hctx->ccid2hctx_srtt) {
unsigned long r = jiffies - seqp->ccid2s_sent;
int s;
/* first measurement */
if (hctx->ccid2hctx_srtt == -1) {
ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
r, jiffies, seqp->ccid2s_seq);
hctx->ccid2hctx_srtt = r;
hctx->ccid2hctx_rttvar = r >> 1;
}
else {
/* RTTVAR */
long tmp = hctx->ccid2hctx_srtt - r;
if (tmp < 0)
tmp *= -1;
tmp >>= 2;
hctx->ccid2hctx_rttvar *= 3;
hctx->ccid2hctx_rttvar >>= 2;
hctx->ccid2hctx_rttvar += tmp;
/* SRTT */
hctx->ccid2hctx_srtt *= 7;
hctx->ccid2hctx_srtt >>= 3;
tmp = r >> 3;
hctx->ccid2hctx_srtt += tmp;
}
s = hctx->ccid2hctx_rttvar << 2;
/* clock granularity is 1 when based on jiffies */
if (!s)
s = 1;
hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
/* must be at least a second */
s = hctx->ccid2hctx_rto / HZ;
/* DCCP doesn't require this [but I like it cuz my code sux] */
#if 1
if (s < 1)
hctx->ccid2hctx_rto = HZ;
#endif
/* max 60 seconds */
if (s > 60)
hctx->ccid2hctx_rto = HZ * 60;
hctx->ccid2hctx_lastrtt = jiffies;
ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
hctx->ccid2hctx_rto, HZ, r);
hctx->ccid2hctx_sent = 0;
}
/* we got a new ack, so re-start RTO timer */
ccid2_hc_tx_kill_rto_timer(hctx);
ccid2_start_rto_timer(sk);
}
static void ccid2_hc_tx_dec_pipe(struct ccid2_hc_tx_sock *hctx)
{
hctx->ccid2hctx_pipe--;
BUG_ON(hctx->ccid2hctx_pipe < 0);
if (hctx->ccid2hctx_pipe == 0)
ccid2_hc_tx_kill_rto_timer(hctx);
}
static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
u64 ackno, seqno;
struct ccid2_seq *seqp;
unsigned char *vector;
unsigned char veclen;
int offset = 0;
int done = 0;
int loss = 0;
unsigned int maxincr = 0;
ccid2_hc_tx_check_sanity(hctx);
/* check reverse path congestion */
seqno = DCCP_SKB_CB(skb)->dccpd_seq;
/* XXX this whole "algorithm" is broken. Need to fix it to keep track
* of the seqnos of the dupacks so that rpseq and rpdupack are correct
* -sorbo.
*/
/* need to bootstrap */
if (hctx->ccid2hctx_rpdupack == -1) {
hctx->ccid2hctx_rpdupack = 0;
hctx->ccid2hctx_rpseq = seqno;
}
else {
/* check if packet is consecutive */
if ((hctx->ccid2hctx_rpseq + 1) == seqno) {
hctx->ccid2hctx_rpseq++;
}
/* it's a later packet */
else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
hctx->ccid2hctx_rpdupack++;
/* check if we got enough dupacks */
if (hctx->ccid2hctx_rpdupack >=
hctx->ccid2hctx_numdupack) {
hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
hctx->ccid2hctx_rpseq = 0;
ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
}
}
}
/* check forward path congestion */
/* still didn't send out new data packets */
if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
return;
switch (DCCP_SKB_CB(skb)->dccpd_type) {
case DCCP_PKT_ACK:
case DCCP_PKT_DATAACK:
break;
default:
return;
}
ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
/* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
* this single ack. I round up.
* -sorbo.
*/
maxincr = dp->dccps_l_ack_ratio >> 1;
maxincr++;
/* go through all ack vectors */
while ((offset = ccid2_ackvector(sk, skb, offset,
&vector, &veclen)) != -1) {
/* go through this ack vector */
while (veclen--) {
const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
u64 ackno_end_rl;
dccp_set_seqno(&ackno_end_rl, ackno - rl);
ccid2_pr_debug("ackvec start:%llu end:%llu\n", ackno,
ackno_end_rl);
/* if the seqno we are analyzing is larger than the
* current ackno, then move towards the tail of our
* seqnos.
*/
while (after48(seqp->ccid2s_seq, ackno)) {
if (seqp == hctx->ccid2hctx_seqt) {
done = 1;
break;
}
seqp = seqp->ccid2s_prev;
}
if (done)
break;
/* check all seqnos in the range of the vector
* run length
*/
while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
const u8 state = (*vector &
DCCP_ACKVEC_STATE_MASK) >> 6;
/* new packet received or marked */
if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
!seqp->ccid2s_acked) {
if (state ==
DCCP_ACKVEC_STATE_ECN_MARKED) {
loss = 1;
}
else {
ccid2_new_ack(sk, seqp,
&maxincr);
}
seqp->ccid2s_acked = 1;
ccid2_pr_debug("Got ack for %llu\n",
seqp->ccid2s_seq);
ccid2_hc_tx_dec_pipe(hctx);
}
if (seqp == hctx->ccid2hctx_seqt) {
done = 1;
break;
}
seqp = seqp->ccid2s_next;
}
if (done)
break;
dccp_set_seqno(&ackno, ackno_end_rl - 1);
vector++;
}
if (done)
break;
}
/* The state about what is acked should be correct now
* Check for NUMDUPACK
*/
seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
done = 0;
while (1) {
if (seqp->ccid2s_acked) {
done++;
if (done == hctx->ccid2hctx_numdupack) {
break;
}
}
if (seqp == hctx->ccid2hctx_seqt) {
break;
}
seqp = seqp->ccid2s_prev;
}
/* If there are at least 3 acknowledgements, anything unacknowledged
* below the last sequence number is considered lost
*/
if (done == hctx->ccid2hctx_numdupack) {
struct ccid2_seq *last_acked = seqp;
/* check for lost packets */
while (1) {
if (!seqp->ccid2s_acked) {
loss = 1;
ccid2_hc_tx_dec_pipe(hctx);
}
if (seqp == hctx->ccid2hctx_seqt)
break;
seqp = seqp->ccid2s_prev;
}
hctx->ccid2hctx_seqt = last_acked;
}
/* trim acked packets in tail */
while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
if (!hctx->ccid2hctx_seqt->ccid2s_acked)
break;
hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
}
if (loss) {
/* XXX do bit shifts guarantee a 0 as the new bit? */
ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd >> 1);
hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
if (hctx->ccid2hctx_ssthresh < 2)
hctx->ccid2hctx_ssthresh = 2;
}
ccid2_hc_tx_check_sanity(hctx);
}
static int ccid2_hc_tx_init(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hctx;
int seqcount = ccid2_seq_len;
int i;
dp->dccps_hc_tx_ccid_private = kzalloc(sizeof(*hctx), gfp_any());
if (dp->dccps_hc_tx_ccid_private == NULL)
return -ENOMEM;
hctx = ccid2_hc_tx_sk(sk);
/* XXX init variables with proper values */
hctx->ccid2hctx_cwnd = 1;
hctx->ccid2hctx_ssthresh = 10;
hctx->ccid2hctx_numdupack = 3;
/* XXX init ~ to window size... */
hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) *
seqcount, gfp_any());
if (hctx->ccid2hctx_seqbuf == NULL) {
kfree(dp->dccps_hc_tx_ccid_private);
dp->dccps_hc_tx_ccid_private = NULL;
return -ENOMEM;
}
for (i = 0; i < (seqcount - 1); i++) {
hctx->ccid2hctx_seqbuf[i].ccid2s_next =
&hctx->ccid2hctx_seqbuf[i + 1];
hctx->ccid2hctx_seqbuf[i + 1].ccid2s_prev =
&hctx->ccid2hctx_seqbuf[i];
}
hctx->ccid2hctx_seqbuf[seqcount - 1].ccid2s_next =
hctx->ccid2hctx_seqbuf;
hctx->ccid2hctx_seqbuf->ccid2s_prev =
&hctx->ccid2hctx_seqbuf[seqcount - 1];
hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqbuf;
hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
hctx->ccid2hctx_sent = 0;
hctx->ccid2hctx_rto = 3 * HZ;
hctx->ccid2hctx_srtt = -1;
hctx->ccid2hctx_rttvar = -1;
hctx->ccid2hctx_lastrtt = 0;
hctx->ccid2hctx_rpdupack = -1;
hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
init_timer(&hctx->ccid2hctx_rtotimer);
ccid2_hc_tx_check_sanity(hctx);
return 0;
}
static void ccid2_hc_tx_exit(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
ccid2_hc_tx_kill_rto_timer(hctx);
kfree(hctx->ccid2hctx_seqbuf);
kfree(dp->dccps_hc_tx_ccid_private);
dp->dccps_hc_tx_ccid_private = NULL;
}
static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
const struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
switch (DCCP_SKB_CB(skb)->dccpd_type) {
case DCCP_PKT_DATA:
case DCCP_PKT_DATAACK:
hcrx->ccid2hcrx_data++;
if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
dccp_send_ack(sk);
hcrx->ccid2hcrx_data = 0;
}
break;
}
}
static int ccid2_hc_rx_init(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
dp->dccps_hc_rx_ccid_private = kzalloc(sizeof(struct ccid2_hc_rx_sock),
gfp_any());
return dp->dccps_hc_rx_ccid_private == NULL ? -ENOMEM : 0;
}
static void ccid2_hc_rx_exit(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
kfree(dp->dccps_hc_rx_ccid_private);
dp->dccps_hc_rx_ccid_private = NULL;
}
static struct ccid ccid2 = {
.ccid_id = 2,
.ccid_name = "ccid2",
.ccid_owner = THIS_MODULE,
.ccid_hc_tx_init = ccid2_hc_tx_init,
.ccid_hc_tx_exit = ccid2_hc_tx_exit,
.ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
.ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
.ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
.ccid_hc_rx_init = ccid2_hc_rx_init,
.ccid_hc_rx_exit = ccid2_hc_rx_exit,
.ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
};
module_param(ccid2_debug, int, 0444);
MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
static __init int ccid2_module_init(void)
{
return ccid_register(&ccid2);
}
module_init(ccid2_module_init);
static __exit void ccid2_module_exit(void)
{
ccid_unregister(&ccid2);
}
module_exit(ccid2_module_exit);
MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
MODULE_DESCRIPTION("DCCP TCP CCID2 CCID");
MODULE_LICENSE("GPL");
MODULE_ALIAS("net-dccp-ccid-2");

69
net/dccp/ccids/ccid2.h Normal file
View file

@ -0,0 +1,69 @@
/*
* net/dccp/ccids/ccid2.h
*
* Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
*
* 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.
*/
#ifndef _DCCP_CCID2_H_
#define _DCCP_CCID2_H_
struct ccid2_seq {
u64 ccid2s_seq;
unsigned long ccid2s_sent;
int ccid2s_acked;
struct ccid2_seq *ccid2s_prev;
struct ccid2_seq *ccid2s_next;
};
/** struct ccid2_hc_tx_sock - CCID2 TX half connection
*
* @ccid2hctx_ssacks - ACKs recv in slow start
* @ccid2hctx_acks - ACKS recv in AI phase
* @ccid2hctx_sent - packets sent in this window
* @ccid2hctx_lastrtt -time RTT was last measured
* @ccid2hctx_arsent - packets sent [ack ratio]
* @ccid2hctx_ackloss - ack was lost in this win
* @ccid2hctx_rpseq - last consecutive seqno
* @ccid2hctx_rpdupack - dupacks since rpseq
*/
struct ccid2_hc_tx_sock {
int ccid2hctx_cwnd;
int ccid2hctx_ssacks;
int ccid2hctx_acks;
int ccid2hctx_ssthresh;
int ccid2hctx_pipe;
int ccid2hctx_numdupack;
struct ccid2_seq *ccid2hctx_seqbuf;
struct ccid2_seq *ccid2hctx_seqh;
struct ccid2_seq *ccid2hctx_seqt;
long ccid2hctx_rto;
long ccid2hctx_srtt;
long ccid2hctx_rttvar;
int ccid2hctx_sent;
unsigned long ccid2hctx_lastrtt;
struct timer_list ccid2hctx_rtotimer;
unsigned long ccid2hctx_arsent;
int ccid2hctx_ackloss;
u64 ccid2hctx_rpseq;
int ccid2hctx_rpdupack;
int ccid2hctx_sendwait;
};
struct ccid2_hc_rx_sock {
int ccid2hcrx_data;
};
#endif /* _DCCP_CCID2_H_ */

1
net/dccp/ipv4.c
View file

@ -1081,6 +1081,7 @@ int dccp_v4_init_sock(struct sock *sk)
dp->dccps_mss_cache = 536;
dp->dccps_role = DCCP_ROLE_UNDEFINED;
dp->dccps_service = DCCP_SERVICE_INVALID_VALUE;
dp->dccps_l_ack_ratio = dp->dccps_r_ack_ratio = 1;
return 0;
}