1 files changed, 565 insertions, 0 deletions

diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
new file mode 100644
index 000000000..16277b6a0
--- /dev/null
+++ b/net/sched/sch_red.c
@@ -0,0 +1,565 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * net/sched/sch_red.c	Random Early Detection queue.
+ *
+ * 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;
+	/* Non-flags in tc_red_qopt.flags. */
+	unsigned char		userbits;
+
+	struct timer_list	adapt_timer;
+	struct Qdisc		*sch;
+	struct red_parms	parms;
+	struct red_vars		vars;
+	struct red_stats	stats;
+	struct Qdisc		*qdisc;
+	struct tcf_qevent	qe_early_drop;
+	struct tcf_qevent	qe_mark;
+};
+
+#define TC_RED_SUPPORTED_FLAGS (TC_RED_HISTORIC_FLAGS | TC_RED_NODROP)
+
+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_use_nodrop(struct red_sched_data *q)
+{
+	return q->flags & TC_RED_NODROP;
+}
+
+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;
+	unsigned int len;
+	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)) {
+			q->stats.prob_drop++;
+			goto congestion_drop;
+		}
+
+		if (INET_ECN_set_ce(skb)) {
+			q->stats.prob_mark++;
+			skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret);
+			if (!skb)
+				return NET_XMIT_CN | ret;
+		} else if (!red_use_nodrop(q)) {
+			q->stats.prob_drop++;
+			goto congestion_drop;
+		}
+
+		/* Non-ECT packet in ECN nodrop mode: queue it. */
+		break;
+
+	case RED_HARD_MARK:
+		qdisc_qstats_overlimit(sch);
+		if (red_use_harddrop(q) || !red_use_ecn(q)) {
+			q->stats.forced_drop++;
+			goto congestion_drop;
+		}
+
+		if (INET_ECN_set_ce(skb)) {
+			q->stats.forced_mark++;
+			skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret);
+			if (!skb)
+				return NET_XMIT_CN | ret;
+		} else if (!red_use_nodrop(q)) {
+			q->stats.forced_drop++;
+			goto congestion_drop;
+		}
+
+		/* Non-ECT packet in ECN nodrop mode: queue it. */
+		break;
+	}
+
+	len = qdisc_pkt_len(skb);
+	ret = qdisc_enqueue(skb, child, to_free);
+	if (likely(ret == NET_XMIT_SUCCESS)) {
+		sch->qstats.backlog += len;
+		sch->q.qlen++;
+	} else if (net_xmit_drop_count(ret)) {
+		q->stats.pdrop++;
+		qdisc_qstats_drop(sch);
+	}
+	return ret;
+
+congestion_drop:
+	skb = tcf_qevent_handle(&q->qe_early_drop, sch, skb, to_free, &ret);
+	if (!skb)
+		return NET_XMIT_CN | ret;
+
+	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);
+	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.is_nodrop = red_use_nodrop(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);
+
+	tcf_qevent_destroy(&q->qe_mark, sch);
+	tcf_qevent_destroy(&q->qe_early_drop, 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_UNSPEC] = { .strict_start_type = TCA_RED_FLAGS },
+	[TCA_RED_PARMS]	= { .len = sizeof(struct tc_red_qopt) },
+	[TCA_RED_STAB]	= { .len = RED_STAB_SIZE },
+	[TCA_RED_MAX_P] = { .type = NLA_U32 },
+	[TCA_RED_FLAGS] = NLA_POLICY_BITFIELD32(TC_RED_SUPPORTED_FLAGS),
+	[TCA_RED_EARLY_DROP_BLOCK] = { .type = NLA_U32 },
+	[TCA_RED_MARK_BLOCK] = { .type = NLA_U32 },
+};
+
+static int __red_change(struct Qdisc *sch, struct nlattr **tb,
+			struct netlink_ext_ack *extack)
+{
+	struct Qdisc *old_child = NULL, *child = NULL;
+	struct red_sched_data *q = qdisc_priv(sch);
+	struct nla_bitfield32 flags_bf;
+	struct tc_red_qopt *ctl;
+	unsigned char userbits;
+	unsigned char flags;
+	int err;
+	u32 max_P;
+	u8 *stab;
+
+	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]);
+	stab = nla_data(tb[TCA_RED_STAB]);
+	if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog,
+			      ctl->Scell_log, stab))
+		return -EINVAL;
+
+	err = red_get_flags(ctl->flags, TC_RED_HISTORIC_FLAGS,
+			    tb[TCA_RED_FLAGS], TC_RED_SUPPORTED_FLAGS,
+			    &flags_bf, &userbits, extack);
+	if (err)
+		return err;
+
+	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);
+
+	flags = (q->flags & ~flags_bf.selector) | flags_bf.value;
+	err = red_validate_flags(flags, extack);
+	if (err)
+		goto unlock_out;
+
+	q->flags = flags;
+	q->userbits = userbits;
+	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,
+		      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;
+
+unlock_out:
+	sch_tree_unlock(sch);
+	if (child)
+		qdisc_put(child);
+	return err;
+}
+
+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;
+
+	rcu_read_lock();
+	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);
+	rcu_read_unlock();
+}
+
+static int red_init(struct Qdisc *sch, struct nlattr *opt,
+		    struct netlink_ext_ack *extack)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+	struct nlattr *tb[TCA_RED_MAX + 1];
+	int err;
+
+	q->qdisc = &noop_qdisc;
+	q->sch = sch;
+	timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
+
+	if (!opt)
+		return -EINVAL;
+
+	err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
+					  extack);
+	if (err < 0)
+		return err;
+
+	err = __red_change(sch, tb, extack);
+	if (err)
+		return err;
+
+	err = tcf_qevent_init(&q->qe_early_drop, sch,
+			      FLOW_BLOCK_BINDER_TYPE_RED_EARLY_DROP,
+			      tb[TCA_RED_EARLY_DROP_BLOCK], extack);
+	if (err)
+		return err;
+
+	return tcf_qevent_init(&q->qe_mark, sch,
+			       FLOW_BLOCK_BINDER_TYPE_RED_MARK,
+			       tb[TCA_RED_MARK_BLOCK], extack);
+}
+
+static int red_change(struct Qdisc *sch, struct nlattr *opt,
+		      struct netlink_ext_ack *extack)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+	struct nlattr *tb[TCA_RED_MAX + 1];
+	int err;
+
+	err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
+					  extack);
+	if (err < 0)
+		return err;
+
+	err = tcf_qevent_validate_change(&q->qe_early_drop,
+					 tb[TCA_RED_EARLY_DROP_BLOCK], extack);
+	if (err)
+		return err;
+
+	err = tcf_qevent_validate_change(&q->qe_mark,
+					 tb[TCA_RED_MARK_BLOCK], extack);
+	if (err)
+		return err;
+
+	return __red_change(sch, tb, 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 & TC_RED_HISTORIC_FLAGS) |
+				  q->userbits,
+		.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_noflag(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) ||
+	    nla_put_bitfield32(skb, TCA_RED_FLAGS,
+			       q->flags, TC_RED_SUPPORTED_FLAGS) ||
+	    tcf_qevent_dump(skb, TCA_RED_MARK_BLOCK, &q->qe_mark) ||
+	    tcf_qevent_dump(skb, TCA_RED_EARLY_DROP_BLOCK, &q->qe_early_drop))
+		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.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) {
+		tc_qdisc_stats_dump(sch, 1, walker);
+	}
+}
+
+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");