/*
* Compare flow of two packets
* Returns true only if source and destination address and port match.
* false for special cases
*/
static bool choke_match_flow(struct sk_buff *skb1,
struct sk_buff *skb2)
{
if (skb1->protocol != skb2->protocol)
return false;
if (!choke_skb_cb(skb1)->keys_valid) {
choke_skb_cb(skb1)->keys_valid = 1;
skb_flow_dissect(skb1, &choke_skb_cb(skb1)->keys);
}
if (!choke_skb_cb(skb2)->keys_valid) {
choke_skb_cb(skb2)->keys_valid = 1;
skb_flow_dissect(skb2, &choke_skb_cb(skb2)->keys);
}
return !memcmp(&choke_skb_cb(skb1)->keys,
&choke_skb_cb(skb2)->keys,
sizeof(struct flow_keys));
}
static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
struct choke_sched_data *q = qdisc_priv(sch);
const struct red_parms *p = &q->parms;
int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
if (q->filter_list) {
/* If using external classifiers, get result and record it. */
if (!choke_classify(skb, sch, &ret))
goto other_drop; /* Packet was eaten by filter */
}
choke_skb_cb(skb)->keys_valid = 0;
/* Compute average queue usage (see RED) */
q->vars.qavg = red_calc_qavg(p, &q->vars, sch->q.qlen);
if (red_is_idling(&q->vars))
red_end_of_idle_period(&q->vars);
/* Is queue small? */
if (q->vars.qavg <= p->qth_min)
q->vars.qcount = -1;
else {
unsigned int idx;
/* Draw a packet at random from queue and compare flow */
if (choke_match_random(q, skb, &idx)) {
q->stats.matched++;
choke_drop_by_idx(sch, idx);
goto congestion_drop;
}
/* Queue is large, always mark/drop */
if (q->vars.qavg > p->qth_max) {
q->vars.qcount = -1;
sch->qstats.overlimits++;
if (use_harddrop(q) || !use_ecn(q) ||
!INET_ECN_set_ce(skb)) {
q->stats.forced_drop++;
goto congestion_drop;
}
q->stats.forced_mark++;
} else if (++q->vars.qcount) {
if (red_mark_probability(p, &q->vars, q->vars.qavg)) {
q->vars.qcount = 0;
q->vars.qR = red_random(p);
sch->qstats.overlimits++;
if (!use_ecn(q) || !INET_ECN_set_ce(skb)) {
q->stats.prob_drop++;
goto congestion_drop;
}
q->stats.prob_mark++;
}
} else
q->vars.qR = red_random(p);
}
/* Admit new packet */
if (sch->q.qlen < q->limit) {
q->tab[q->tail] = skb;
q->tail = (q->tail + 1) & q->tab_mask;
++sch->q.qlen;
sch->qstats.backlog += qdisc_pkt_len(skb);
return NET_XMIT_SUCCESS;
}
q->stats.pdrop++;
sch->qstats.drops++;
kfree_skb(skb);
return NET_XMIT_DROP;
congestion_drop:
qdisc_drop(skb, sch);
return NET_XMIT_CN;
other_drop:
if (ret & __NET_XMIT_BYPASS)
sch->qstats.drops++;
kfree_skb(skb);
return ret;
}
static inline void choke_set_classid(struct sk_buff *skb, u16 classid)
{
choke_skb_cb(skb)->classid = classid;
}
static u16 choke_get_classid(const struct sk_buff *skb)
{
return choke_skb_cb(skb)->classid;
}
static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
struct choke_sched_data *q = qdisc_priv(sch);
const struct red_parms *p = &q->parms;
choke_skb_cb(skb)->keys_valid = 0;
/* Compute average queue usage (see RED) */
q->vars.qavg = red_calc_qavg(p, &q->vars, sch->q.qlen);
if (red_is_idling(&q->vars))
red_end_of_idle_period(&q->vars);
/* Is queue small? */
if (q->vars.qavg <= p->qth_min)
q->vars.qcount = -1;
else {
unsigned int idx;
/* Draw a packet at random from queue and compare flow */
if (choke_match_random(q, skb, &idx)) {
q->stats.matched++;
choke_drop_by_idx(sch, idx, to_free);
goto congestion_drop;
}
/* Queue is large, always mark/drop */
if (q->vars.qavg > p->qth_max) {
q->vars.qcount = -1;
qdisc_qstats_overlimit(sch);
if (use_harddrop(q) || !use_ecn(q) ||
!INET_ECN_set_ce(skb)) {
q->stats.forced_drop++;
goto congestion_drop;
}
q->stats.forced_mark++;
} else if (++q->vars.qcount) {
if (red_mark_probability(p, &q->vars, q->vars.qavg)) {
q->vars.qcount = 0;
q->vars.qR = red_random(p);
qdisc_qstats_overlimit(sch);
if (!use_ecn(q) || !INET_ECN_set_ce(skb)) {
q->stats.prob_drop++;
goto congestion_drop;
}
q->stats.prob_mark++;
}
} else
q->vars.qR = red_random(p);
}
/* Admit new packet */
if (sch->q.qlen < q->limit) {
q->tab[q->tail] = skb;
q->tail = (q->tail + 1) & q->tab_mask;
++sch->q.qlen;
qdisc_qstats_backlog_inc(sch, skb);
return NET_XMIT_SUCCESS;
}
q->stats.pdrop++;
return qdisc_drop(skb, sch, to_free);
congestion_drop:
qdisc_drop(skb, sch, to_free);
return NET_XMIT_CN;
}