*/
/*
- * This implementation should follow: draft-ietf-dccp-ccid2-10.txt
+ * This implementation should follow RFC 4341
*
* BUGS:
* - sequence number wrapping
- * - jiffies wrapping
*/
#include "../ccid.h"
#include "../dccp.h"
#include "ccid2.h"
-static int ccid2_debug;
-
-#undef CCID2_DEBUG
-#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;
+#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
+static int ccid2_debug;
+#define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
-#ifdef CCID2_DEBUG
static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
{
int len = 0;
/* 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);
+ BUG_ON(time_before(seqp->ccid2s_sent,
+ prev->ccid2s_sent));
seqp = prev;
}
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);
+ BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN);
}
#else
-#define ccid2_hc_tx_check_sanity(hctx) do {} while (0)
+#define ccid2_pr_debug(format, a...)
+#define ccid2_hc_tx_check_sanity(hctx)
#endif
-static int ccid2_hc_tx_send_packet(struct sock *sk,
- struct sk_buff *skb, int len)
+static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx, int num,
+ gfp_t gfp)
+{
+ struct ccid2_seq *seqp;
+ int i;
+
+ /* check if we have space to preserve the pointer to the buffer */
+ if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) /
+ sizeof(struct ccid2_seq*)))
+ return -ENOMEM;
+
+ /* allocate buffer and initialize linked list */
+ seqp = kmalloc(sizeof(*seqp) * num, gfp);
+ if (seqp == NULL)
+ return -ENOMEM;
+
+ for (i = 0; i < (num - 1); i++) {
+ seqp[i].ccid2s_next = &seqp[i + 1];
+ seqp[i + 1].ccid2s_prev = &seqp[i];
+ }
+ seqp[num - 1].ccid2s_next = seqp;
+ seqp->ccid2s_prev = &seqp[num - 1];
+
+ /* This is the first allocation. Initiate the head and tail. */
+ if (hctx->ccid2hctx_seqbufc == 0)
+ hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp;
+ else {
+ /* link the existing list with the one we just created */
+ hctx->ccid2hctx_seqh->ccid2s_next = seqp;
+ seqp->ccid2s_prev = hctx->ccid2hctx_seqh;
+
+ hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[num - 1];
+ seqp[num - 1].ccid2s_next = hctx->ccid2hctx_seqt;
+ }
+
+ /* store the original pointer to the buffer so we can free it */
+ hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp;
+ hctx->ccid2hctx_seqbufc++;
+
+ return 0;
+}
+
+static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
{
struct ccid2_hc_tx_sock *hctx;
}
}
- return 100; /* XXX */
+ return 1; /* XXX CCID should dequeue when ready instead of polling */
}
static void ccid2_change_l_ack_ratio(struct sock *sk, int val)
dp->dccps_l_ack_ratio = val;
}
-static void ccid2_change_cwnd(struct sock *sk, int val)
+static void ccid2_change_cwnd(struct ccid2_hc_tx_sock *hctx, int val)
{
- struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
-
if (val == 0)
val = 1;
hctx->ccid2hctx_cwnd = val;
}
+static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
+{
+ ccid2_pr_debug("change SRTT to %ld\n", val);
+ hctx->ccid2hctx_srtt = val;
+}
+
+static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val)
+{
+ hctx->ccid2hctx_pipe = val;
+}
+
static void ccid2_start_rto_timer(struct sock *sk);
static void ccid2_hc_tx_rto_expire(unsigned long data)
ccid2_start_rto_timer(sk);
/* adjust pipe, cwnd etc */
- hctx->ccid2hctx_pipe = 0;
+ ccid2_change_pipe(hctx, 0);
hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
if (hctx->ccid2hctx_ssthresh < 2)
hctx->ccid2hctx_ssthresh = 2;
- ccid2_change_cwnd(sk, 1);
+ ccid2_change_cwnd(hctx, 1);
/* clear state about stuff we sent */
hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
jiffies + hctx->ccid2hctx_rto);
}
-static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len)
+static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+ struct ccid2_seq *next;
u64 seq;
ccid2_hc_tx_check_sanity(hctx);
BUG_ON(!hctx->ccid2hctx_sendwait);
hctx->ccid2hctx_sendwait = 0;
- hctx->ccid2hctx_pipe++;
+ ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe + 1);
BUG_ON(hctx->ccid2hctx_pipe < 0);
/* There is an issue. What if another packet is sent between
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);
+ next = hctx->ccid2hctx_seqh->ccid2s_next;
+ /* check if we need to alloc more space */
+ if (next == hctx->ccid2hctx_seqt) {
+ int rc;
+
+ ccid2_pr_debug("allocating more space in history\n");
+ rc = ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_KERNEL);
+ BUG_ON(rc); /* XXX what do we do? */
- if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) {
- /* XXX allocate more space */
- WARN_ON(1);
+ next = hctx->ccid2hctx_seqh->ccid2s_next;
+ BUG_ON(next == hctx->ccid2hctx_seqt);
}
+ hctx->ccid2hctx_seqh = next;
+
+ ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
+ hctx->ccid2hctx_pipe);
hctx->ccid2hctx_sent++;
if (!timer_pending(&hctx->ccid2hctx_rtotimer))
ccid2_start_rto_timer(sk);
-#ifdef CCID2_DEBUG
+#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
- ccid2_pr_debug("Sent: seq=%llu\n", seq);
+ ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)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);
+ (unsigned long long)seqp->ccid2s_seq,
+ seqp->ccid2s_acked, seqp->ccid2s_sent);
seqp = seqp->ccid2s_next;
}
} while (0);
return -1;
out_invalid_option:
- BUG_ON(1); /* should never happen... options were previously parsed ! */
+ DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
return -1;
}
/* increase every 2 acks */
hctx->ccid2hctx_ssacks++;
if (hctx->ccid2hctx_ssacks == 2) {
- ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1);
+ ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd+1);
hctx->ccid2hctx_ssacks = 0;
*maxincr = *maxincr - 1;
}
hctx->ccid2hctx_acks++;
if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
- ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1);
+ ccid2_change_cwnd(hctx, 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;
+ time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
+ unsigned long r = (long)jiffies - (long)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;
+ r, jiffies,
+ (unsigned long long)seqp->ccid2s_seq);
+ ccid2_change_srtt(hctx, r);
hctx->ccid2hctx_rttvar = r >> 1;
} else {
/* RTTVAR */
long tmp = hctx->ccid2hctx_srtt - r;
+ long srtt;
+
if (tmp < 0)
tmp *= -1;
hctx->ccid2hctx_rttvar += tmp;
/* SRTT */
- hctx->ccid2hctx_srtt *= 7;
- hctx->ccid2hctx_srtt >>= 3;
+ srtt = hctx->ccid2hctx_srtt;
+ srtt *= 7;
+ srtt >>= 3;
tmp = r >> 3;
- hctx->ccid2hctx_srtt += tmp;
+ srtt += tmp;
+ ccid2_change_srtt(hctx, srtt);
}
s = hctx->ccid2hctx_rttvar << 2;
/* clock granularity is 1 when based on jiffies */
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_srtt, hctx->ccid2hctx_rttvar,
+ hctx->ccid2hctx_rto, HZ, r);
hctx->ccid2hctx_sent = 0;
}
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
- hctx->ccid2hctx_pipe--;
+ ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1);
BUG_ON(hctx->ccid2hctx_pipe < 0);
if (hctx->ccid2hctx_pipe == 0)
ccid2_hc_tx_kill_rto_timer(sk);
}
+static void ccid2_congestion_event(struct ccid2_hc_tx_sock *hctx,
+ struct ccid2_seq *seqp)
+{
+ if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
+ ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
+ return;
+ }
+
+ hctx->ccid2hctx_last_cong = jiffies;
+
+ ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd >> 1);
+ hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
+ if (hctx->ccid2hctx_ssthresh < 2)
+ hctx->ccid2hctx_ssthresh = 2;
+}
+
static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
unsigned char veclen;
int offset = 0;
int done = 0;
- int loss = 0;
unsigned int maxincr = 0;
ccid2_hc_tx_check_sanity(hctx);
}
ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
- seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
+ if (after48(ackno, hctx->ccid2hctx_high_ack))
+ hctx->ccid2hctx_high_ack = ackno;
+
+ seqp = hctx->ccid2hctx_seqt;
+ while (before48(seqp->ccid2s_seq, ackno)) {
+ seqp = seqp->ccid2s_next;
+ if (seqp == hctx->ccid2hctx_seqh) {
+ seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
+ break;
+ }
+ }
/* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
* this single ack. I round up.
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);
+ ccid2_pr_debug("ackvec start:%llu end:%llu\n",
+ (unsigned long long)ackno,
+ (unsigned long long)ackno_end_rl);
/* if the seqno we are analyzing is larger than the
* current ackno, then move towards the tail of our
* seqnos.
* run length
*/
while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
- const u8 state = (*vector &
- DCCP_ACKVEC_STATE_MASK) >> 6;
+ const u8 state = *vector &
+ DCCP_ACKVEC_STATE_MASK;
/* new packet received or marked */
if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
!seqp->ccid2s_acked) {
- if (state ==
+ if (state ==
DCCP_ACKVEC_STATE_ECN_MARKED) {
- loss = 1;
+ ccid2_congestion_event(hctx,
+ seqp);
} else
ccid2_new_ack(sk, seqp,
&maxincr);
seqp->ccid2s_acked = 1;
ccid2_pr_debug("Got ack for %llu\n",
- seqp->ccid2s_seq);
+ (unsigned long long)seqp->ccid2s_seq);
ccid2_hc_tx_dec_pipe(sk);
}
if (seqp == hctx->ccid2hctx_seqt) {
/* The state about what is acked should be correct now
* Check for NUMDUPACK
*/
- seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
+ seqp = hctx->ccid2hctx_seqt;
+ while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
+ seqp = seqp->ccid2s_next;
+ if (seqp == hctx->ccid2hctx_seqh) {
+ seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
+ break;
+ }
+ }
done = 0;
while (1) {
if (seqp->ccid2s_acked) {
/* check for lost packets */
while (1) {
if (!seqp->ccid2s_acked) {
- loss = 1;
+ ccid2_pr_debug("Packet lost: %llu\n",
+ (unsigned long long)seqp->ccid2s_seq);
+ /* XXX need to traverse from tail -> head in
+ * order to detect multiple congestion events in
+ * one ack vector.
+ */
+ ccid2_congestion_event(hctx, seqp);
ccid2_hc_tx_dec_pipe(sk);
}
if (seqp == hctx->ccid2hctx_seqt)
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 ccid *ccid, struct sock *sk)
{
struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
- int seqcount = ccid2_seq_len;
- int i;
- /* XXX init variables with proper values */
- hctx->ccid2hctx_cwnd = 1;
- hctx->ccid2hctx_ssthresh = 10;
+ ccid2_change_cwnd(hctx, 1);
+ /* Initialize ssthresh to infinity. This means that we will exit the
+ * initial slow-start after the first packet loss. This is what we
+ * want.
+ */
+ hctx->ccid2hctx_ssthresh = ~0;
hctx->ccid2hctx_numdupack = 3;
+ hctx->ccid2hctx_seqbufc = 0;
/* XXX init ~ to window size... */
- hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) *
- seqcount, gfp_any());
- if (hctx->ccid2hctx_seqbuf == NULL)
+ if (ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_ATOMIC) != 0)
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;
+ ccid2_change_srtt(hctx, -1);
hctx->ccid2hctx_rttvar = -1;
hctx->ccid2hctx_lastrtt = 0;
hctx->ccid2hctx_rpdupack = -1;
+ hctx->ccid2hctx_last_cong = jiffies;
+ hctx->ccid2hctx_high_ack = 0;
hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
static void ccid2_hc_tx_exit(struct sock *sk)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+ int i;
ccid2_hc_tx_kill_rto_timer(sk);
- kfree(hctx->ccid2hctx_seqbuf);
- hctx->ccid2hctx_seqbuf = NULL;
+
+ for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
+ kfree(hctx->ccid2hctx_seqbuf[i]);
+ hctx->ccid2hctx_seqbufc = 0;
}
static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
}
static struct ccid_operations ccid2 = {
- .ccid_id = 2,
+ .ccid_id = DCCPC_CCID2,
.ccid_name = "ccid2",
.ccid_owner = THIS_MODULE,
.ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
.ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
};
+#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
module_param(ccid2_debug, int, 0444);
MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
+#endif
static __init int ccid2_module_init(void)
{
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