1 files changed, 388 insertions, 0 deletions

diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
new file mode 100644
index 0000000..5da0583
--- /dev/null
+++ b/net/sched/sch_red.c
@@ -0,0 +1,388 @@
+/*
+ * 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/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 red_parms	parms;
+	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 red_sched_data *q = qdisc_priv(sch);
+	struct Qdisc *child = q->qdisc;
+	int ret;
+
+	q->parms.qavg = red_calc_qavg(&q->parms, child->qstats.backlog);
+
+	if (red_is_idling(&q->parms))
+		red_end_of_idle_period(&q->parms);
+
+	switch (red_action(&q->parms, q->parms.qavg)) {
+		case RED_DONT_MARK:
+			break;
+
+		case RED_PROB_MARK:
+			sch->qstats.overlimits++;
+			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:
+			sch->qstats.overlimits++;
+			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);
+	if (likely(ret == NET_XMIT_SUCCESS)) {
+		sch->bstats.bytes += qdisc_pkt_len(skb);
+		sch->bstats.packets++;
+		sch->q.qlen++;
+	} else if (net_xmit_drop_count(ret)) {
+		q->stats.pdrop++;
+		sch->qstats.drops++;
+	}
+	return ret;
+
+congestion_drop:
+	qdisc_drop(skb, sch);
+	return NET_XMIT_CN;
+}
+
+static int red_requeue(struct sk_buff *skb, struct Qdisc* sch)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+	struct Qdisc *child = q->qdisc;
+	int ret;
+
+	if (red_is_idling(&q->parms))
+		red_end_of_idle_period(&q->parms);
+
+	ret = child->ops->requeue(skb, child);
+	if (likely(ret == NET_XMIT_SUCCESS)) {
+		sch->qstats.requeues++;
+		sch->q.qlen++;
+	}
+	return ret;
+}
+
+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)
+		sch->q.qlen--;
+	else if (!red_is_idling(&q->parms))
+		red_start_of_idle_period(&q->parms);
+
+	return skb;
+}
+
+static unsigned int red_drop(struct Qdisc* sch)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+	struct Qdisc *child = q->qdisc;
+	unsigned int len;
+
+	if (child->ops->drop && (len = child->ops->drop(child)) > 0) {
+		q->stats.other++;
+		sch->qstats.drops++;
+		sch->q.qlen--;
+		return len;
+	}
+
+	if (!red_is_idling(&q->parms))
+		red_start_of_idle_period(&q->parms);
+
+	return 0;
+}
+
+static void red_reset(struct Qdisc* sch)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+
+	qdisc_reset(q->qdisc);
+	sch->q.qlen = 0;
+	red_restart(&q->parms);
+}
+
+static void red_destroy(struct Qdisc *sch)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+	qdisc_destroy(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 },
+};
+
+static int red_change(struct Qdisc *sch, struct nlattr *opt)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+	struct nlattr *tb[TCA_RED_MAX + 1];
+	struct tc_red_qopt *ctl;
+	struct Qdisc *child = NULL;
+	int err;
+
+	if (opt == NULL)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_RED_PARMS] == NULL ||
+	    tb[TCA_RED_STAB] == NULL)
+		return -EINVAL;
+
+	ctl = nla_data(tb[TCA_RED_PARMS]);
+
+	if (ctl->limit > 0) {
+		child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit);
+		if (IS_ERR(child))
+			return PTR_ERR(child);
+	}
+
+	sch_tree_lock(sch);
+	q->flags = ctl->flags;
+	q->limit = ctl->limit;
+	if (child) {
+		qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
+		qdisc_destroy(xchg(&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]));
+
+	if (skb_queue_empty(&sch->q))
+		red_end_of_idle_period(&q->parms);
+
+	sch_tree_unlock(sch);
+	return 0;
+}
+
+static int red_init(struct Qdisc* sch, struct nlattr *opt)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+
+	q->qdisc = &noop_qdisc;
+	return red_change(sch, opt);
+}
+
+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,
+	};
+
+	opts = nla_nest_start(skb, TCA_OPTIONS);
+	if (opts == NULL)
+		goto nla_put_failure;
+	NLA_PUT(skb, TCA_RED_PARMS, sizeof(opt), &opt);
+	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 tc_red_xstats st = {
+		.early	= q->stats.prob_drop + q->stats.forced_drop,
+		.pdrop	= q->stats.pdrop,
+		.other	= q->stats.other,
+		.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);
+
+	if (cl != 1)
+		return -ENOENT;
+	tcm->tcm_handle |= TC_H_MIN(1);
+	tcm->tcm_info = q->qdisc->handle;
+	return 0;
+}
+
+static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
+		     struct Qdisc **old)
+{
+	struct red_sched_data *q = qdisc_priv(sch);
+
+	if (new == NULL)
+		new = &noop_qdisc;
+
+	sch_tree_lock(sch);
+	*old = xchg(&q->qdisc, new);
+	qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
+	qdisc_reset(*old);
+	sch_tree_unlock(sch);
+	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_get(struct Qdisc *sch, u32 classid)
+{
+	return 1;
+}
+
+static void red_put(struct Qdisc *sch, unsigned long arg)
+{
+	return;
+}
+
+static int red_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
+			    struct nlattr **tca, unsigned long *arg)
+{
+	return -ENOSYS;
+}
+
+static int red_delete(struct Qdisc *sch, unsigned long cl)
+{
+	return -ENOSYS;
+}
+
+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 struct tcf_proto **red_find_tcf(struct Qdisc *sch, unsigned long cl)
+{
+	return NULL;
+}
+
+static const struct Qdisc_class_ops red_class_ops = {
+	.graft		=	red_graft,
+	.leaf		=	red_leaf,
+	.get		=	red_get,
+	.put		=	red_put,
+	.change		=	red_change_class,
+	.delete		=	red_delete,
+	.walk		=	red_walk,
+	.tcf_chain	=	red_find_tcf,
+	.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,
+	.requeue	=	red_requeue,
+	.drop		=	red_drop,
+	.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");