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310 lines
8.5 KiB
310 lines
8.5 KiB
/* |
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* Codel - The Controlled-Delay Active Queue Management algorithm |
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* |
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* Copyright (C) 2011-2012 Kathleen Nichols <[email protected]> |
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* Copyright (C) 2011-2012 Van Jacobson <[email protected]> |
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* |
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* Implemented on linux by : |
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* Copyright (C) 2012 Michael D. Taht <[email protected]> |
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* Copyright (C) 2012,2015 Eric Dumazet <[email protected]> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions, and the following disclaimer, |
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* without modification. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. The names of the authors may not be used to endorse or promote products |
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* derived from this software without specific prior written permission. |
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* |
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* Alternatively, provided that this notice is retained in full, this |
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* software may be distributed under the terms of the GNU General |
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* Public License ("GPL") version 2, in which case the provisions of the |
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* GPL apply INSTEAD OF those given above. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
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* DAMAGE. |
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* |
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*/ |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/skbuff.h> |
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#include <linux/prefetch.h> |
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#include <net/pkt_sched.h> |
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#include <net/codel.h> |
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#include <net/codel_impl.h> |
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#include <net/codel_qdisc.h> |
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#define DEFAULT_CODEL_LIMIT 1000 |
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struct codel_sched_data { |
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struct codel_params params; |
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struct codel_vars vars; |
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struct codel_stats stats; |
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u32 drop_overlimit; |
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}; |
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/* This is the specific function called from codel_dequeue() |
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* to dequeue a packet from queue. Note: backlog is handled in |
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* codel, we dont need to reduce it here. |
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*/ |
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static struct sk_buff *dequeue_func(struct codel_vars *vars, void *ctx) |
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{ |
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struct Qdisc *sch = ctx; |
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struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); |
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if (skb) { |
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sch->qstats.backlog -= qdisc_pkt_len(skb); |
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prefetch(&skb->end); /* we'll need skb_shinfo() */ |
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} |
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return skb; |
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} |
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static void drop_func(struct sk_buff *skb, void *ctx) |
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{ |
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struct Qdisc *sch = ctx; |
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kfree_skb(skb); |
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qdisc_qstats_drop(sch); |
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} |
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static struct sk_buff *codel_qdisc_dequeue(struct Qdisc *sch) |
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{ |
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struct codel_sched_data *q = qdisc_priv(sch); |
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struct sk_buff *skb; |
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skb = codel_dequeue(sch, &sch->qstats.backlog, &q->params, &q->vars, |
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&q->stats, qdisc_pkt_len, codel_get_enqueue_time, |
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drop_func, dequeue_func); |
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/* We cant call qdisc_tree_reduce_backlog() if our qlen is 0, |
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* or HTB crashes. Defer it for next round. |
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*/ |
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if (q->stats.drop_count && sch->q.qlen) { |
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qdisc_tree_reduce_backlog(sch, q->stats.drop_count, q->stats.drop_len); |
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q->stats.drop_count = 0; |
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q->stats.drop_len = 0; |
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} |
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if (skb) |
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qdisc_bstats_update(sch, skb); |
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return skb; |
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} |
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static int codel_qdisc_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 codel_sched_data *q; |
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if (likely(qdisc_qlen(sch) < sch->limit)) { |
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codel_set_enqueue_time(skb); |
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return qdisc_enqueue_tail(skb, sch); |
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} |
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q = qdisc_priv(sch); |
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q->drop_overlimit++; |
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return qdisc_drop(skb, sch, to_free); |
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} |
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static const struct nla_policy codel_policy[TCA_CODEL_MAX + 1] = { |
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[TCA_CODEL_TARGET] = { .type = NLA_U32 }, |
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[TCA_CODEL_LIMIT] = { .type = NLA_U32 }, |
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[TCA_CODEL_INTERVAL] = { .type = NLA_U32 }, |
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[TCA_CODEL_ECN] = { .type = NLA_U32 }, |
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[TCA_CODEL_CE_THRESHOLD]= { .type = NLA_U32 }, |
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}; |
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static int codel_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 codel_sched_data *q = qdisc_priv(sch); |
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struct nlattr *tb[TCA_CODEL_MAX + 1]; |
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unsigned int qlen, dropped = 0; |
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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_CODEL_MAX, opt, |
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codel_policy, NULL); |
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if (err < 0) |
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return err; |
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sch_tree_lock(sch); |
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if (tb[TCA_CODEL_TARGET]) { |
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u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]); |
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q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT; |
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} |
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if (tb[TCA_CODEL_CE_THRESHOLD]) { |
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u64 val = nla_get_u32(tb[TCA_CODEL_CE_THRESHOLD]); |
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q->params.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT; |
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} |
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if (tb[TCA_CODEL_INTERVAL]) { |
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u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]); |
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q->params.interval = ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT; |
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} |
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if (tb[TCA_CODEL_LIMIT]) |
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sch->limit = nla_get_u32(tb[TCA_CODEL_LIMIT]); |
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if (tb[TCA_CODEL_ECN]) |
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q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]); |
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qlen = sch->q.qlen; |
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while (sch->q.qlen > sch->limit) { |
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struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); |
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dropped += qdisc_pkt_len(skb); |
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qdisc_qstats_backlog_dec(sch, skb); |
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rtnl_qdisc_drop(skb, sch); |
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} |
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qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped); |
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sch_tree_unlock(sch); |
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return 0; |
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} |
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static int codel_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 codel_sched_data *q = qdisc_priv(sch); |
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sch->limit = DEFAULT_CODEL_LIMIT; |
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codel_params_init(&q->params); |
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codel_vars_init(&q->vars); |
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codel_stats_init(&q->stats); |
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q->params.mtu = psched_mtu(qdisc_dev(sch)); |
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if (opt) { |
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int err = codel_change(sch, opt, extack); |
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if (err) |
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return err; |
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} |
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if (sch->limit >= 1) |
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sch->flags |= TCQ_F_CAN_BYPASS; |
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else |
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sch->flags &= ~TCQ_F_CAN_BYPASS; |
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return 0; |
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} |
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static int codel_dump(struct Qdisc *sch, struct sk_buff *skb) |
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{ |
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struct codel_sched_data *q = qdisc_priv(sch); |
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struct nlattr *opts; |
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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_u32(skb, TCA_CODEL_TARGET, |
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codel_time_to_us(q->params.target)) || |
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nla_put_u32(skb, TCA_CODEL_LIMIT, |
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sch->limit) || |
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nla_put_u32(skb, TCA_CODEL_INTERVAL, |
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codel_time_to_us(q->params.interval)) || |
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nla_put_u32(skb, TCA_CODEL_ECN, |
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q->params.ecn)) |
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goto nla_put_failure; |
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if (q->params.ce_threshold != CODEL_DISABLED_THRESHOLD && |
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nla_put_u32(skb, TCA_CODEL_CE_THRESHOLD, |
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codel_time_to_us(q->params.ce_threshold))) |
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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 -1; |
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} |
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static int codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d) |
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{ |
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const struct codel_sched_data *q = qdisc_priv(sch); |
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struct tc_codel_xstats st = { |
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.maxpacket = q->stats.maxpacket, |
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.count = q->vars.count, |
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.lastcount = q->vars.lastcount, |
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.drop_overlimit = q->drop_overlimit, |
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.ldelay = codel_time_to_us(q->vars.ldelay), |
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.dropping = q->vars.dropping, |
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.ecn_mark = q->stats.ecn_mark, |
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.ce_mark = q->stats.ce_mark, |
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}; |
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if (q->vars.dropping) { |
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codel_tdiff_t delta = q->vars.drop_next - codel_get_time(); |
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if (delta >= 0) |
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st.drop_next = codel_time_to_us(delta); |
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else |
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st.drop_next = -codel_time_to_us(-delta); |
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} |
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return gnet_stats_copy_app(d, &st, sizeof(st)); |
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} |
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static void codel_reset(struct Qdisc *sch) |
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{ |
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struct codel_sched_data *q = qdisc_priv(sch); |
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qdisc_reset_queue(sch); |
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codel_vars_init(&q->vars); |
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} |
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static struct Qdisc_ops codel_qdisc_ops __read_mostly = { |
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.id = "codel", |
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.priv_size = sizeof(struct codel_sched_data), |
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.enqueue = codel_qdisc_enqueue, |
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.dequeue = codel_qdisc_dequeue, |
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.peek = qdisc_peek_dequeued, |
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.init = codel_init, |
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.reset = codel_reset, |
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.change = codel_change, |
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.dump = codel_dump, |
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.dump_stats = codel_dump_stats, |
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.owner = THIS_MODULE, |
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}; |
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static int __init codel_module_init(void) |
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{ |
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return register_qdisc(&codel_qdisc_ops); |
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} |
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static void __exit codel_module_exit(void) |
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{ |
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unregister_qdisc(&codel_qdisc_ops); |
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} |
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module_init(codel_module_init) |
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module_exit(codel_module_exit) |
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MODULE_DESCRIPTION("Controlled Delay queue discipline"); |
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MODULE_AUTHOR("Dave Taht"); |
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MODULE_AUTHOR("Eric Dumazet"); |
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MODULE_LICENSE("Dual BSD/GPL");
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