[DCCP] CCID2: Initial CCID2 (TCP-Like) implementation
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>
diff --git a/net/dccp/Kconfig b/net/dccp/Kconfig
index 187ac18..24a6981 100644
--- a/net/dccp/Kconfig
+++ b/net/dccp/Kconfig
@@ -24,6 +24,10 @@
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"
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
index 7684d83..422af19 100644
--- a/net/dccp/ccids/Kconfig
+++ b/net/dccp/ccids/Kconfig
@@ -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 @@
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.
diff --git a/net/dccp/ccids/Makefile b/net/dccp/ccids/Makefile
index 956f79f..438f20b 100644
--- a/net/dccp/ccids/Makefile
+++ b/net/dccp/ccids/Makefile
@@ -2,4 +2,8 @@
dccp_ccid3-y := ccid3.o
+obj-$(CONFIG_IP_DCCP_CCID2) += dccp_ccid2.o
+
+dccp_ccid2-y := ccid2.o
+
obj-y += lib/
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
new file mode 100644
index 0000000..4a7b875
--- /dev/null
+++ b/net/dccp/ccids/ccid2.c
@@ -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");
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
new file mode 100644
index 0000000..0b08c90
--- /dev/null
+++ b/net/dccp/ccids/ccid2.h
@@ -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_ */
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 2ab6f0e..38321ad 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -1081,6 +1081,7 @@
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;
}