| /* |
| * net/sched/sch_red.c Random Early Detection queue. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> |
| * |
| * Changes: |
| * J Hadi Salim 980914: computation fixes |
| * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly. |
| * J Hadi Salim 980816: ECN support |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/skbuff.h> |
| #include <net/pkt_sched.h> |
| #include <net/pkt_cls.h> |
| #include <net/inet_ecn.h> |
| #include <net/red.h> |
| |
| |
| /* Parameters, settable by user: |
| ----------------------------- |
| |
| limit - bytes (must be > qth_max + burst) |
| |
| Hard limit on queue length, should be chosen >qth_max |
| to allow packet bursts. This parameter does not |
| affect the algorithms behaviour and can be chosen |
| arbitrarily high (well, less than ram size) |
| Really, this limit will never be reached |
| if RED works correctly. |
| */ |
| |
| struct red_sched_data { |
| u32 limit; /* HARD maximal queue length */ |
| unsigned char flags; |
| struct timer_list adapt_timer; |
| struct Qdisc *sch; |
| struct red_parms parms; |
| struct red_vars vars; |
| struct red_stats stats; |
| struct Qdisc *qdisc; |
| }; |
| |
| static inline int red_use_ecn(struct red_sched_data *q) |
| { |
| return q->flags & TC_RED_ECN; |
| } |
| |
| static inline int red_use_harddrop(struct red_sched_data *q) |
| { |
| return q->flags & TC_RED_HARDDROP; |
| } |
| |
| static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
| struct sk_buff **to_free) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| struct Qdisc *child = q->qdisc; |
| int ret; |
| |
| q->vars.qavg = red_calc_qavg(&q->parms, |
| &q->vars, |
| child->qstats.backlog); |
| |
| if (red_is_idling(&q->vars)) |
| red_end_of_idle_period(&q->vars); |
| |
| switch (red_action(&q->parms, &q->vars, q->vars.qavg)) { |
| case RED_DONT_MARK: |
| break; |
| |
| case RED_PROB_MARK: |
| qdisc_qstats_overlimit(sch); |
| if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) { |
| q->stats.prob_drop++; |
| goto congestion_drop; |
| } |
| |
| q->stats.prob_mark++; |
| break; |
| |
| case RED_HARD_MARK: |
| qdisc_qstats_overlimit(sch); |
| if (red_use_harddrop(q) || !red_use_ecn(q) || |
| !INET_ECN_set_ce(skb)) { |
| q->stats.forced_drop++; |
| goto congestion_drop; |
| } |
| |
| q->stats.forced_mark++; |
| break; |
| } |
| |
| ret = qdisc_enqueue(skb, child, to_free); |
| if (likely(ret == NET_XMIT_SUCCESS)) { |
| qdisc_qstats_backlog_inc(sch, skb); |
| sch->q.qlen++; |
| } else if (net_xmit_drop_count(ret)) { |
| q->stats.pdrop++; |
| qdisc_qstats_drop(sch); |
| } |
| return ret; |
| |
| congestion_drop: |
| qdisc_drop(skb, sch, to_free); |
| return NET_XMIT_CN; |
| } |
| |
| static struct sk_buff *red_dequeue(struct Qdisc *sch) |
| { |
| struct sk_buff *skb; |
| struct red_sched_data *q = qdisc_priv(sch); |
| struct Qdisc *child = q->qdisc; |
| |
| skb = child->dequeue(child); |
| if (skb) { |
| qdisc_bstats_update(sch, skb); |
| qdisc_qstats_backlog_dec(sch, skb); |
| sch->q.qlen--; |
| } else { |
| if (!red_is_idling(&q->vars)) |
| red_start_of_idle_period(&q->vars); |
| } |
| return skb; |
| } |
| |
| static struct sk_buff *red_peek(struct Qdisc *sch) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| struct Qdisc *child = q->qdisc; |
| |
| return child->ops->peek(child); |
| } |
| |
| static void red_reset(struct Qdisc *sch) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| |
| qdisc_reset(q->qdisc); |
| sch->qstats.backlog = 0; |
| sch->q.qlen = 0; |
| red_restart(&q->vars); |
| } |
| |
| static int red_offload(struct Qdisc *sch, bool enable) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| struct net_device *dev = qdisc_dev(sch); |
| struct tc_red_qopt_offload opt = { |
| .handle = sch->handle, |
| .parent = sch->parent, |
| }; |
| |
| if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) |
| return -EOPNOTSUPP; |
| |
| if (enable) { |
| opt.command = TC_RED_REPLACE; |
| opt.set.min = q->parms.qth_min >> q->parms.Wlog; |
| opt.set.max = q->parms.qth_max >> q->parms.Wlog; |
| opt.set.probability = q->parms.max_P; |
| opt.set.limit = q->limit; |
| opt.set.is_ecn = red_use_ecn(q); |
| opt.set.is_harddrop = red_use_harddrop(q); |
| opt.set.qstats = &sch->qstats; |
| } else { |
| opt.command = TC_RED_DESTROY; |
| } |
| |
| return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt); |
| } |
| |
| static void red_destroy(struct Qdisc *sch) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| |
| del_timer_sync(&q->adapt_timer); |
| red_offload(sch, false); |
| qdisc_put(q->qdisc); |
| } |
| |
| static const struct nla_policy red_policy[TCA_RED_MAX + 1] = { |
| [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) }, |
| [TCA_RED_STAB] = { .len = RED_STAB_SIZE }, |
| [TCA_RED_MAX_P] = { .type = NLA_U32 }, |
| }; |
| |
| static int red_change(struct Qdisc *sch, struct nlattr *opt, |
| struct netlink_ext_ack *extack) |
| { |
| struct Qdisc *old_child = NULL, *child = NULL; |
| struct red_sched_data *q = qdisc_priv(sch); |
| struct nlattr *tb[TCA_RED_MAX + 1]; |
| struct tc_red_qopt *ctl; |
| int err; |
| u32 max_P; |
| |
| if (opt == NULL) |
| return -EINVAL; |
| |
| err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy, NULL); |
| if (err < 0) |
| return err; |
| |
| if (tb[TCA_RED_PARMS] == NULL || |
| tb[TCA_RED_STAB] == NULL) |
| return -EINVAL; |
| |
| max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0; |
| |
| ctl = nla_data(tb[TCA_RED_PARMS]); |
| if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog)) |
| return -EINVAL; |
| |
| if (ctl->limit > 0) { |
| child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit, |
| extack); |
| if (IS_ERR(child)) |
| return PTR_ERR(child); |
| |
| /* child is fifo, no need to check for noop_qdisc */ |
| qdisc_hash_add(child, true); |
| } |
| |
| sch_tree_lock(sch); |
| q->flags = ctl->flags; |
| q->limit = ctl->limit; |
| if (child) { |
| qdisc_tree_flush_backlog(q->qdisc); |
| old_child = q->qdisc; |
| q->qdisc = child; |
| } |
| |
| red_set_parms(&q->parms, |
| ctl->qth_min, ctl->qth_max, ctl->Wlog, |
| ctl->Plog, ctl->Scell_log, |
| nla_data(tb[TCA_RED_STAB]), |
| max_P); |
| red_set_vars(&q->vars); |
| |
| del_timer(&q->adapt_timer); |
| if (ctl->flags & TC_RED_ADAPTATIVE) |
| mod_timer(&q->adapt_timer, jiffies + HZ/2); |
| |
| if (!q->qdisc->q.qlen) |
| red_start_of_idle_period(&q->vars); |
| |
| sch_tree_unlock(sch); |
| |
| red_offload(sch, true); |
| |
| if (old_child) |
| qdisc_put(old_child); |
| return 0; |
| } |
| |
| static inline void red_adaptative_timer(struct timer_list *t) |
| { |
| struct red_sched_data *q = from_timer(q, t, adapt_timer); |
| struct Qdisc *sch = q->sch; |
| spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); |
| |
| spin_lock(root_lock); |
| red_adaptative_algo(&q->parms, &q->vars); |
| mod_timer(&q->adapt_timer, jiffies + HZ/2); |
| spin_unlock(root_lock); |
| } |
| |
| static int red_init(struct Qdisc *sch, struct nlattr *opt, |
| struct netlink_ext_ack *extack) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| |
| q->qdisc = &noop_qdisc; |
| q->sch = sch; |
| timer_setup(&q->adapt_timer, red_adaptative_timer, 0); |
| return red_change(sch, opt, extack); |
| } |
| |
| static int red_dump_offload_stats(struct Qdisc *sch) |
| { |
| struct tc_red_qopt_offload hw_stats = { |
| .command = TC_RED_STATS, |
| .handle = sch->handle, |
| .parent = sch->parent, |
| { |
| .stats.bstats = &sch->bstats, |
| .stats.qstats = &sch->qstats, |
| }, |
| }; |
| |
| return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats); |
| } |
| |
| static int red_dump(struct Qdisc *sch, struct sk_buff *skb) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| struct nlattr *opts = NULL; |
| struct tc_red_qopt opt = { |
| .limit = q->limit, |
| .flags = q->flags, |
| .qth_min = q->parms.qth_min >> q->parms.Wlog, |
| .qth_max = q->parms.qth_max >> q->parms.Wlog, |
| .Wlog = q->parms.Wlog, |
| .Plog = q->parms.Plog, |
| .Scell_log = q->parms.Scell_log, |
| }; |
| int err; |
| |
| err = red_dump_offload_stats(sch); |
| if (err) |
| goto nla_put_failure; |
| |
| opts = nla_nest_start(skb, TCA_OPTIONS); |
| if (opts == NULL) |
| goto nla_put_failure; |
| if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) || |
| nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P)) |
| goto nla_put_failure; |
| return nla_nest_end(skb, opts); |
| |
| nla_put_failure: |
| nla_nest_cancel(skb, opts); |
| return -EMSGSIZE; |
| } |
| |
| static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| struct net_device *dev = qdisc_dev(sch); |
| struct tc_red_xstats st = {0}; |
| |
| if (sch->flags & TCQ_F_OFFLOADED) { |
| struct tc_red_qopt_offload hw_stats_request = { |
| .command = TC_RED_XSTATS, |
| .handle = sch->handle, |
| .parent = sch->parent, |
| { |
| .xstats = &q->stats, |
| }, |
| }; |
| dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, |
| &hw_stats_request); |
| } |
| st.early = q->stats.prob_drop + q->stats.forced_drop; |
| st.pdrop = q->stats.pdrop; |
| st.other = q->stats.other; |
| st.marked = q->stats.prob_mark + q->stats.forced_mark; |
| |
| return gnet_stats_copy_app(d, &st, sizeof(st)); |
| } |
| |
| static int red_dump_class(struct Qdisc *sch, unsigned long cl, |
| struct sk_buff *skb, struct tcmsg *tcm) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| |
| tcm->tcm_handle |= TC_H_MIN(1); |
| tcm->tcm_info = q->qdisc->handle; |
| return 0; |
| } |
| |
| static void red_graft_offload(struct Qdisc *sch, |
| struct Qdisc *new, struct Qdisc *old, |
| struct netlink_ext_ack *extack) |
| { |
| struct tc_red_qopt_offload graft_offload = { |
| .handle = sch->handle, |
| .parent = sch->parent, |
| .child_handle = new->handle, |
| .command = TC_RED_GRAFT, |
| }; |
| |
| qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old, |
| TC_SETUP_QDISC_RED, &graft_offload, extack); |
| } |
| |
| static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, |
| struct Qdisc **old, struct netlink_ext_ack *extack) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| |
| if (new == NULL) |
| new = &noop_qdisc; |
| |
| *old = qdisc_replace(sch, new, &q->qdisc); |
| |
| red_graft_offload(sch, new, *old, extack); |
| return 0; |
| } |
| |
| static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg) |
| { |
| struct red_sched_data *q = qdisc_priv(sch); |
| return q->qdisc; |
| } |
| |
| static unsigned long red_find(struct Qdisc *sch, u32 classid) |
| { |
| return 1; |
| } |
| |
| static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker) |
| { |
| if (!walker->stop) { |
| if (walker->count >= walker->skip) |
| if (walker->fn(sch, 1, walker) < 0) { |
| walker->stop = 1; |
| return; |
| } |
| walker->count++; |
| } |
| } |
| |
| static const struct Qdisc_class_ops red_class_ops = { |
| .graft = red_graft, |
| .leaf = red_leaf, |
| .find = red_find, |
| .walk = red_walk, |
| .dump = red_dump_class, |
| }; |
| |
| static struct Qdisc_ops red_qdisc_ops __read_mostly = { |
| .id = "red", |
| .priv_size = sizeof(struct red_sched_data), |
| .cl_ops = &red_class_ops, |
| .enqueue = red_enqueue, |
| .dequeue = red_dequeue, |
| .peek = red_peek, |
| .init = red_init, |
| .reset = red_reset, |
| .destroy = red_destroy, |
| .change = red_change, |
| .dump = red_dump, |
| .dump_stats = red_dump_stats, |
| .owner = THIS_MODULE, |
| }; |
| |
| static int __init red_module_init(void) |
| { |
| return register_qdisc(&red_qdisc_ops); |
| } |
| |
| static void __exit red_module_exit(void) |
| { |
| unregister_qdisc(&red_qdisc_ops); |
| } |
| |
| module_init(red_module_init) |
| module_exit(red_module_exit) |
| |
| MODULE_LICENSE("GPL"); |