static int
sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
struct sfq_sched_data *q = qdisc_priv(sch);
unsigned int hash;
sfq_index x, qlen;
struct sfq_slot *slot;
int uninitialized_var(ret);
struct sk_buff *head;
int delta;
hash = sfq_classify(skb, sch, &ret);
if (hash == 0) {
if (ret & __NET_XMIT_BYPASS)
sch->qstats.drops++;
kfree_skb(skb);
return ret;
}
hash--;
x = q->ht[hash];
slot = &q->slots[x];
if (x == SFQ_EMPTY_SLOT) {
x = q->dep[0].next; /* get a free slot */
if (x >= SFQ_MAX_FLOWS)
return qdisc_drop(skb, sch);
q->ht[hash] = x;
slot = &q->slots[x];
slot->hash = hash;
slot->backlog = 0; /* should already be 0 anyway... */
red_set_vars(&slot->vars);
goto enqueue;
}
if (q->red_parms) {
slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
&slot->vars,
slot->backlog);
switch (red_action(q->red_parms,
&slot->vars,
slot->vars.qavg)) {
case RED_DONT_MARK:
break;
case RED_PROB_MARK:
sch->qstats.overlimits++;
if (sfq_prob_mark(q)) {
/* We know we have at least one packet in queue */
if (sfq_headdrop(q) &&
INET_ECN_set_ce(slot->skblist_next)) {
q->stats.prob_mark_head++;
break;
}
if (INET_ECN_set_ce(skb)) {
q->stats.prob_mark++;
break;
}
}
q->stats.prob_drop++;
goto congestion_drop;
case RED_HARD_MARK:
sch->qstats.overlimits++;
if (sfq_hard_mark(q)) {
/* We know we have at least one packet in queue */
if (sfq_headdrop(q) &&
INET_ECN_set_ce(slot->skblist_next)) {
q->stats.forced_mark_head++;
break;
}
if (INET_ECN_set_ce(skb)) {
q->stats.forced_mark++;
break;
}
}
q->stats.forced_drop++;
goto congestion_drop;
}
}
if (slot->qlen >= q->maxdepth) {
congestion_drop:
if (!sfq_headdrop(q))
return qdisc_drop(skb, sch);
/* We know we have at least one packet in queue */
head = slot_dequeue_head(slot);
delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
sch->qstats.backlog -= delta;
slot->backlog -= delta;
qdisc_drop(head, sch);
slot_queue_add(slot, skb);
return NET_XMIT_CN;
}
enqueue:
sch->qstats.backlog += qdisc_pkt_len(skb);
slot->backlog += qdisc_pkt_len(skb);
slot_queue_add(slot, skb);
sfq_inc(q, x);
if (slot->qlen == 1) { /* The flow is new */
if (q->tail == NULL) { /* It is the first flow */
slot->next = x;
} else {
slot->next = q->tail->next;
q->tail->next = x;
}
/* We put this flow at the end of our flow list.
* This might sound unfair for a new flow to wait after old ones,
* but we could endup servicing new flows only, and freeze old ones.
*/
q->tail = slot;
/* We could use a bigger initial quantum for new flows */
slot->allot = q->scaled_quantum;
}
if (++sch->q.qlen <= q->limit)
return NET_XMIT_SUCCESS;
qlen = slot->qlen;
sfq_drop(sch);
/* Return Congestion Notification only if we dropped a packet
* from this flow.
*/
if (qlen != slot->qlen)
return NET_XMIT_CN;
/* As we dropped a packet, better let upper stack know this */
qdisc_tree_decrease_qlen(sch, 1);
return NET_XMIT_SUCCESS;
}
static int
sfq_requeue(struct sk_buff *skb, struct Qdisc *sch)
{
struct sfq_sched_data *q = qdisc_priv(sch);
unsigned int hash;
sfq_index x;
int ret;
hash = sfq_classify(skb, sch, &ret);
if (hash == 0) {
if (ret == NET_XMIT_BYPASS)
sch->qstats.drops++;
kfree_skb(skb);
return ret;
}
hash--;
x = q->ht[hash];
if (x == SFQ_DEPTH) {
q->ht[hash] = x = q->dep[SFQ_DEPTH].next;
q->hash[x] = hash;
}
sch->qstats.backlog += skb->len;
__skb_queue_head(&q->qs[x], skb);
/* If selected queue has length q->limit+1, this means that
* all another queues are empty and we do simple tail drop.
* This packet is still requeued at head of queue, tail packet
* is dropped.
*/
if (q->qs[x].qlen > q->limit) {
skb = q->qs[x].prev;
__skb_unlink(skb, &q->qs[x]);
sch->qstats.drops++;
sch->qstats.backlog -= skb->len;
kfree_skb(skb);
return NET_XMIT_CN;
}
sfq_inc(q, x);
if (q->qs[x].qlen == 1) { /* The flow is new */
if (q->tail == SFQ_DEPTH) { /* It is the first flow */
q->tail = x;
q->next[x] = x;
q->allot[x] = q->quantum;
} else {
q->next[x] = q->next[q->tail];
q->next[q->tail] = x;
q->tail = x;
}
}
if (++sch->q.qlen <= q->limit) {
sch->qstats.requeues++;
return 0;
}
sch->qstats.drops++;
sfq_drop(sch);
return NET_XMIT_CN;
}
