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571 lines
13 KiB
571 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* net/sched/sch_red.c Random Early Detection queue. |
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* |
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* Authors: Alexey Kuznetsov, <[email protected]> |
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* |
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* Changes: |
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* J Hadi Salim 980914: computation fixes |
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* Alexey Makarenko <[email protected]> 990814: qave on idle link was calculated incorrectly. |
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* J Hadi Salim 980816: ECN support |
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*/ |
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|
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#include <linux/module.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/skbuff.h> |
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#include <net/pkt_sched.h> |
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#include <net/pkt_cls.h> |
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#include <net/inet_ecn.h> |
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#include <net/red.h> |
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/* Parameters, settable by user: |
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----------------------------- |
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limit - bytes (must be > qth_max + burst) |
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Hard limit on queue length, should be chosen >qth_max |
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to allow packet bursts. This parameter does not |
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affect the algorithms behaviour and can be chosen |
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arbitrarily high (well, less than ram size) |
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Really, this limit will never be reached |
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if RED works correctly. |
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*/ |
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struct red_sched_data { |
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u32 limit; /* HARD maximal queue length */ |
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unsigned char flags; |
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/* Non-flags in tc_red_qopt.flags. */ |
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unsigned char userbits; |
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struct timer_list adapt_timer; |
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struct Qdisc *sch; |
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struct red_parms parms; |
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struct red_vars vars; |
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struct red_stats stats; |
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struct Qdisc *qdisc; |
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struct tcf_qevent qe_early_drop; |
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struct tcf_qevent qe_mark; |
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}; |
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#define TC_RED_SUPPORTED_FLAGS (TC_RED_HISTORIC_FLAGS | TC_RED_NODROP) |
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static inline int red_use_ecn(struct red_sched_data *q) |
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{ |
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return q->flags & TC_RED_ECN; |
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} |
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static inline int red_use_harddrop(struct red_sched_data *q) |
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{ |
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return q->flags & TC_RED_HARDDROP; |
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} |
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static int red_use_nodrop(struct red_sched_data *q) |
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{ |
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return q->flags & TC_RED_NODROP; |
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} |
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static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
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struct sk_buff **to_free) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct Qdisc *child = q->qdisc; |
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int ret; |
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q->vars.qavg = red_calc_qavg(&q->parms, |
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&q->vars, |
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child->qstats.backlog); |
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if (red_is_idling(&q->vars)) |
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red_end_of_idle_period(&q->vars); |
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switch (red_action(&q->parms, &q->vars, q->vars.qavg)) { |
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case RED_DONT_MARK: |
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break; |
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case RED_PROB_MARK: |
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qdisc_qstats_overlimit(sch); |
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if (!red_use_ecn(q)) { |
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q->stats.prob_drop++; |
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goto congestion_drop; |
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} |
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if (INET_ECN_set_ce(skb)) { |
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q->stats.prob_mark++; |
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skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret); |
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if (!skb) |
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return NET_XMIT_CN | ret; |
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} else if (!red_use_nodrop(q)) { |
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q->stats.prob_drop++; |
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goto congestion_drop; |
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} |
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/* Non-ECT packet in ECN nodrop mode: queue it. */ |
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break; |
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case RED_HARD_MARK: |
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qdisc_qstats_overlimit(sch); |
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if (red_use_harddrop(q) || !red_use_ecn(q)) { |
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q->stats.forced_drop++; |
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goto congestion_drop; |
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} |
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if (INET_ECN_set_ce(skb)) { |
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q->stats.forced_mark++; |
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skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret); |
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if (!skb) |
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return NET_XMIT_CN | ret; |
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} else if (!red_use_nodrop(q)) { |
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q->stats.forced_drop++; |
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goto congestion_drop; |
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} |
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/* Non-ECT packet in ECN nodrop mode: queue it. */ |
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break; |
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} |
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ret = qdisc_enqueue(skb, child, to_free); |
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if (likely(ret == NET_XMIT_SUCCESS)) { |
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qdisc_qstats_backlog_inc(sch, skb); |
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sch->q.qlen++; |
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} else if (net_xmit_drop_count(ret)) { |
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q->stats.pdrop++; |
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qdisc_qstats_drop(sch); |
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} |
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return ret; |
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congestion_drop: |
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skb = tcf_qevent_handle(&q->qe_early_drop, sch, skb, to_free, &ret); |
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if (!skb) |
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return NET_XMIT_CN | ret; |
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qdisc_drop(skb, sch, to_free); |
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return NET_XMIT_CN; |
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} |
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static struct sk_buff *red_dequeue(struct Qdisc *sch) |
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{ |
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struct sk_buff *skb; |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct Qdisc *child = q->qdisc; |
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skb = child->dequeue(child); |
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if (skb) { |
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qdisc_bstats_update(sch, skb); |
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qdisc_qstats_backlog_dec(sch, skb); |
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sch->q.qlen--; |
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} else { |
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if (!red_is_idling(&q->vars)) |
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red_start_of_idle_period(&q->vars); |
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} |
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return skb; |
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} |
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static struct sk_buff *red_peek(struct Qdisc *sch) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct Qdisc *child = q->qdisc; |
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return child->ops->peek(child); |
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} |
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static void red_reset(struct Qdisc *sch) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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qdisc_reset(q->qdisc); |
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sch->qstats.backlog = 0; |
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sch->q.qlen = 0; |
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red_restart(&q->vars); |
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} |
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static int red_offload(struct Qdisc *sch, bool enable) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct net_device *dev = qdisc_dev(sch); |
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struct tc_red_qopt_offload opt = { |
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.handle = sch->handle, |
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.parent = sch->parent, |
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}; |
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if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) |
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return -EOPNOTSUPP; |
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if (enable) { |
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opt.command = TC_RED_REPLACE; |
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opt.set.min = q->parms.qth_min >> q->parms.Wlog; |
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opt.set.max = q->parms.qth_max >> q->parms.Wlog; |
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opt.set.probability = q->parms.max_P; |
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opt.set.limit = q->limit; |
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opt.set.is_ecn = red_use_ecn(q); |
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opt.set.is_harddrop = red_use_harddrop(q); |
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opt.set.is_nodrop = red_use_nodrop(q); |
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opt.set.qstats = &sch->qstats; |
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} else { |
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opt.command = TC_RED_DESTROY; |
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} |
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return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt); |
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} |
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static void red_destroy(struct Qdisc *sch) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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tcf_qevent_destroy(&q->qe_mark, sch); |
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tcf_qevent_destroy(&q->qe_early_drop, sch); |
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del_timer_sync(&q->adapt_timer); |
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red_offload(sch, false); |
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qdisc_put(q->qdisc); |
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} |
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static const struct nla_policy red_policy[TCA_RED_MAX + 1] = { |
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[TCA_RED_UNSPEC] = { .strict_start_type = TCA_RED_FLAGS }, |
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[TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) }, |
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[TCA_RED_STAB] = { .len = RED_STAB_SIZE }, |
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[TCA_RED_MAX_P] = { .type = NLA_U32 }, |
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[TCA_RED_FLAGS] = NLA_POLICY_BITFIELD32(TC_RED_SUPPORTED_FLAGS), |
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[TCA_RED_EARLY_DROP_BLOCK] = { .type = NLA_U32 }, |
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[TCA_RED_MARK_BLOCK] = { .type = NLA_U32 }, |
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}; |
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static int __red_change(struct Qdisc *sch, struct nlattr **tb, |
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struct netlink_ext_ack *extack) |
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{ |
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struct Qdisc *old_child = NULL, *child = NULL; |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct nla_bitfield32 flags_bf; |
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struct tc_red_qopt *ctl; |
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unsigned char userbits; |
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unsigned char flags; |
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int err; |
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u32 max_P; |
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u8 *stab; |
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if (tb[TCA_RED_PARMS] == NULL || |
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tb[TCA_RED_STAB] == NULL) |
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return -EINVAL; |
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max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0; |
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ctl = nla_data(tb[TCA_RED_PARMS]); |
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stab = nla_data(tb[TCA_RED_STAB]); |
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if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, |
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ctl->Scell_log, stab)) |
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return -EINVAL; |
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err = red_get_flags(ctl->flags, TC_RED_HISTORIC_FLAGS, |
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tb[TCA_RED_FLAGS], TC_RED_SUPPORTED_FLAGS, |
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&flags_bf, &userbits, extack); |
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if (err) |
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return err; |
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if (ctl->limit > 0) { |
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child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit, |
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extack); |
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if (IS_ERR(child)) |
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return PTR_ERR(child); |
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/* child is fifo, no need to check for noop_qdisc */ |
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qdisc_hash_add(child, true); |
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} |
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sch_tree_lock(sch); |
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flags = (q->flags & ~flags_bf.selector) | flags_bf.value; |
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err = red_validate_flags(flags, extack); |
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if (err) |
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goto unlock_out; |
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q->flags = flags; |
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q->userbits = userbits; |
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q->limit = ctl->limit; |
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if (child) { |
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qdisc_tree_flush_backlog(q->qdisc); |
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old_child = q->qdisc; |
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q->qdisc = child; |
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} |
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red_set_parms(&q->parms, |
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ctl->qth_min, ctl->qth_max, ctl->Wlog, |
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ctl->Plog, ctl->Scell_log, |
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stab, |
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max_P); |
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red_set_vars(&q->vars); |
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del_timer(&q->adapt_timer); |
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if (ctl->flags & TC_RED_ADAPTATIVE) |
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mod_timer(&q->adapt_timer, jiffies + HZ/2); |
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if (!q->qdisc->q.qlen) |
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red_start_of_idle_period(&q->vars); |
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sch_tree_unlock(sch); |
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red_offload(sch, true); |
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if (old_child) |
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qdisc_put(old_child); |
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return 0; |
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unlock_out: |
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sch_tree_unlock(sch); |
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if (child) |
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qdisc_put(child); |
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return err; |
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} |
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static inline void red_adaptative_timer(struct timer_list *t) |
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{ |
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struct red_sched_data *q = from_timer(q, t, adapt_timer); |
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struct Qdisc *sch = q->sch; |
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spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); |
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spin_lock(root_lock); |
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red_adaptative_algo(&q->parms, &q->vars); |
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mod_timer(&q->adapt_timer, jiffies + HZ/2); |
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spin_unlock(root_lock); |
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} |
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static int red_init(struct Qdisc *sch, struct nlattr *opt, |
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struct netlink_ext_ack *extack) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct nlattr *tb[TCA_RED_MAX + 1]; |
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int err; |
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q->qdisc = &noop_qdisc; |
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q->sch = sch; |
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timer_setup(&q->adapt_timer, red_adaptative_timer, 0); |
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if (!opt) |
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return -EINVAL; |
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err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy, |
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extack); |
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if (err < 0) |
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return err; |
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err = __red_change(sch, tb, extack); |
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if (err) |
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return err; |
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err = tcf_qevent_init(&q->qe_early_drop, sch, |
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FLOW_BLOCK_BINDER_TYPE_RED_EARLY_DROP, |
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tb[TCA_RED_EARLY_DROP_BLOCK], extack); |
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if (err) |
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return err; |
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return tcf_qevent_init(&q->qe_mark, sch, |
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FLOW_BLOCK_BINDER_TYPE_RED_MARK, |
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tb[TCA_RED_MARK_BLOCK], extack); |
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} |
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static int red_change(struct Qdisc *sch, struct nlattr *opt, |
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struct netlink_ext_ack *extack) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct nlattr *tb[TCA_RED_MAX + 1]; |
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int err; |
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if (!opt) |
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return -EINVAL; |
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err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy, |
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extack); |
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if (err < 0) |
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return err; |
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err = tcf_qevent_validate_change(&q->qe_early_drop, |
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tb[TCA_RED_EARLY_DROP_BLOCK], extack); |
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if (err) |
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return err; |
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err = tcf_qevent_validate_change(&q->qe_mark, |
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tb[TCA_RED_MARK_BLOCK], extack); |
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if (err) |
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return err; |
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return __red_change(sch, tb, extack); |
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} |
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static int red_dump_offload_stats(struct Qdisc *sch) |
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{ |
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struct tc_red_qopt_offload hw_stats = { |
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.command = TC_RED_STATS, |
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.handle = sch->handle, |
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.parent = sch->parent, |
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{ |
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.stats.bstats = &sch->bstats, |
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.stats.qstats = &sch->qstats, |
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}, |
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}; |
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return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats); |
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} |
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static int red_dump(struct Qdisc *sch, struct sk_buff *skb) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct nlattr *opts = NULL; |
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struct tc_red_qopt opt = { |
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.limit = q->limit, |
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.flags = (q->flags & TC_RED_HISTORIC_FLAGS) | |
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q->userbits, |
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.qth_min = q->parms.qth_min >> q->parms.Wlog, |
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.qth_max = q->parms.qth_max >> q->parms.Wlog, |
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.Wlog = q->parms.Wlog, |
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.Plog = q->parms.Plog, |
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.Scell_log = q->parms.Scell_log, |
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}; |
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int err; |
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err = red_dump_offload_stats(sch); |
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if (err) |
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goto nla_put_failure; |
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opts = nla_nest_start_noflag(skb, TCA_OPTIONS); |
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if (opts == NULL) |
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goto nla_put_failure; |
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if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) || |
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nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P) || |
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nla_put_bitfield32(skb, TCA_RED_FLAGS, |
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q->flags, TC_RED_SUPPORTED_FLAGS) || |
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tcf_qevent_dump(skb, TCA_RED_MARK_BLOCK, &q->qe_mark) || |
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tcf_qevent_dump(skb, TCA_RED_EARLY_DROP_BLOCK, &q->qe_early_drop)) |
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goto nla_put_failure; |
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return nla_nest_end(skb, opts); |
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nla_put_failure: |
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nla_nest_cancel(skb, opts); |
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return -EMSGSIZE; |
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} |
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static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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struct net_device *dev = qdisc_dev(sch); |
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struct tc_red_xstats st = {0}; |
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if (sch->flags & TCQ_F_OFFLOADED) { |
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struct tc_red_qopt_offload hw_stats_request = { |
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.command = TC_RED_XSTATS, |
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.handle = sch->handle, |
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.parent = sch->parent, |
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{ |
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.xstats = &q->stats, |
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}, |
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}; |
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dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, |
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&hw_stats_request); |
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} |
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st.early = q->stats.prob_drop + q->stats.forced_drop; |
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st.pdrop = q->stats.pdrop; |
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st.other = q->stats.other; |
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st.marked = q->stats.prob_mark + q->stats.forced_mark; |
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return gnet_stats_copy_app(d, &st, sizeof(st)); |
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} |
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static int red_dump_class(struct Qdisc *sch, unsigned long cl, |
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struct sk_buff *skb, struct tcmsg *tcm) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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tcm->tcm_handle |= TC_H_MIN(1); |
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tcm->tcm_info = q->qdisc->handle; |
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return 0; |
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} |
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static void red_graft_offload(struct Qdisc *sch, |
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struct Qdisc *new, struct Qdisc *old, |
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struct netlink_ext_ack *extack) |
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{ |
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struct tc_red_qopt_offload graft_offload = { |
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.handle = sch->handle, |
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.parent = sch->parent, |
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.child_handle = new->handle, |
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.command = TC_RED_GRAFT, |
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}; |
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qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old, |
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TC_SETUP_QDISC_RED, &graft_offload, extack); |
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} |
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static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, |
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struct Qdisc **old, struct netlink_ext_ack *extack) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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if (new == NULL) |
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new = &noop_qdisc; |
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*old = qdisc_replace(sch, new, &q->qdisc); |
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red_graft_offload(sch, new, *old, extack); |
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return 0; |
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} |
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static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg) |
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{ |
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struct red_sched_data *q = qdisc_priv(sch); |
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return q->qdisc; |
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} |
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static unsigned long red_find(struct Qdisc *sch, u32 classid) |
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{ |
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return 1; |
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} |
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static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker) |
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{ |
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if (!walker->stop) { |
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if (walker->count >= walker->skip) |
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if (walker->fn(sch, 1, walker) < 0) { |
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walker->stop = 1; |
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return; |
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} |
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walker->count++; |
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} |
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} |
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static const struct Qdisc_class_ops red_class_ops = { |
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.graft = red_graft, |
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.leaf = red_leaf, |
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.find = red_find, |
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.walk = red_walk, |
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.dump = red_dump_class, |
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}; |
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|
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static struct Qdisc_ops red_qdisc_ops __read_mostly = { |
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.id = "red", |
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.priv_size = sizeof(struct red_sched_data), |
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.cl_ops = &red_class_ops, |
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.enqueue = red_enqueue, |
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.dequeue = red_dequeue, |
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.peek = red_peek, |
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.init = red_init, |
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.reset = red_reset, |
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.destroy = red_destroy, |
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.change = red_change, |
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.dump = red_dump, |
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.dump_stats = red_dump_stats, |
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.owner = THIS_MODULE, |
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}; |
|
|
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static int __init red_module_init(void) |
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{ |
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return register_qdisc(&red_qdisc_ops); |
|
} |
|
|
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static void __exit red_module_exit(void) |
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{ |
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unregister_qdisc(&red_qdisc_ops); |
|
} |
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|
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module_init(red_module_init) |
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module_exit(red_module_exit) |
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|
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MODULE_LICENSE("GPL");
|
|
|