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);
if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
if (*maxincr > 0 && ++hctx->ccid2hctx_packets_acked == 2) {
hctx->ccid2hctx_cwnd += 1;
*maxincr -= 1;
hctx->ccid2hctx_packets_acked = 0;
}
} else if (++hctx->ccid2hctx_packets_acked >= hctx->ccid2hctx_cwnd) {
hctx->ccid2hctx_cwnd += 1;
hctx->ccid2hctx_packets_acked = 0;
}
/* update RTO */
if (hctx->ccid2hctx_srtt == -1 ||
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,
(unsigned long long)seqp->ccid2s_seq);
ccid2_change_srtt(hctx, r);
hctx->ccid2hctx_rttvar = r >> 1;
} else {
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_hc_tx_kill_rto_timer(struct sock *sk)
{
struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
ccid2_pr_debug("deleted RTO timer\n");
}
static void ccid2_start_rto_timer(struct sock *sk)
{
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
ccid2_pr_debug("setting RTO timeout=%ld\n", hc->tx_rto);
BUG_ON(timer_pending(&hc->tx_rtotimer));
sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
}
static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
{
int len = 0;
int pipe = 0;
struct ccid2_seq *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 = seqp->ccid2s_prev;
len++;
if (!prev->ccid2s_acked)
pipe++;
/* packets are sent sequentially */
BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq,
prev->ccid2s_seq ) >= 0);
BUG_ON(time_before(seqp->ccid2s_sent,
prev->ccid2s_sent));
seqp = prev;
}
}
BUG_ON(pipe != hctx->ccid2hctx_pipe);
ccid2_pr_debug("len of chain=%d\n", len);
do {
seqp = seqp->ccid2s_prev;
len++;
} while (seqp != hctx->ccid2hctx_seqh);
ccid2_pr_debug("total len=%d\n", len);
BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN);
}
static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
{
int len = 0;
int pipe = 0;
struct ccid2_seq *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 = 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);
}
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_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;
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 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;
}
} else {
/* increased cwnd enough for this single ack */
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 {
static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
{
struct dccp_sock *dp = dccp_sk(sk);
u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->ccid2hctx_cwnd, 2);
/*
* Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from
* RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always
* acceptable since this causes starvation/deadlock whenever cwnd < 2.
* The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled).
*/
if (val == 0 || val > max_ratio) {
DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
val = max_ratio;
}
if (val > DCCPF_ACK_RATIO_MAX)
val = DCCPF_ACK_RATIO_MAX;
if (val == dp->dccps_l_ack_ratio)
return;
ccid2_pr_debug("changing local ack ratio to %u\n", val);
dp->dccps_l_ack_ratio = val;
}
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) {
const 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_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;
hctx->ccid2hctx_pipe++;
hctx->ccid2hctx_seqh->ccid2s_seq = dp->dccps_gss;
hctx->ccid2hctx_seqh->ccid2s_acked = 0;
hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
next = hctx->ccid2hctx_seqh->ccid2s_next;
/* check if we need to alloc more space */
if (next == hctx->ccid2hctx_seqt) {
if (ccid2_hc_tx_alloc_seq(hctx)) {
DCCP_CRIT("packet history - out of memory!");
/* FIXME: find a more graceful way to bail out */
return;
}
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);
/*
* FIXME: The code below is broken and the variables have been removed
* from the socket struct. The `ackloss' variable was always set to 0,
* and with arsent there are several problems:
* (i) it doesn't just count the number of Acks, but all sent packets;
* (ii) it is expressed in # of packets, not # of windows, so the
* comparison below uses the wrong formula: Appendix A of RFC 4341
* comes up with the number K = cwnd / (R^2 - R) of consecutive windows
* of data with no lost or marked Ack packets. If arsent were the # of
* consecutive Acks received without loss, then Ack Ratio needs to be
* decreased by 1 when
* arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2)
* where cwnd / R is the number of Acks received per window of data
* (cf. RFC 4341, App. A). The problems are that
* - arsent counts other packets as well;
* - the comparison uses a formula different from RFC 4341;
* - computing a cubic/quadratic equation each time is too complicated.
* Hence a different algorithm is needed.
*/
#if 0
/* 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;
}
} else {
/* No acks lost up to now... */
/* decrease ack ratio if enough packets were sent */
if (dp->dccps_l_ack_ratio > 1) {
/* XXX don't calculate denominator each time */
int 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;
}
} else {
/* we can't increase ack ratio further [1] */
hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
}
}
#endif
/* setup RTO timer */
if (!timer_pending(&hctx->ccid2hctx_rtotimer))
ccid2_start_rto_timer(sk);
#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
do {
struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
while (seqp != hctx->ccid2hctx_seqh) {
ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
(unsigned long long)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
}
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_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;
}
} else {
/* No acks lost up to now... */
/* decrease ack ratio if enough packets were sent */
if (dp->dccps_l_ack_ratio > 1) {
/* XXX don't calculate denominator each time */
int 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;
}
} else {
/* we can't increase ack ratio further [1] */
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
}