1 files changed, 630 insertions, 0 deletions

diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
new file mode 100644
index 000000000..634529e0c
--- /dev/null
+++ b/net/sched/sch_gred.c
@@ -0,0 +1,630 @@
+/*
+ * net/sched/sch_gred.c	Generic 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:    J Hadi Salim (hadi@cyberus.ca) 1998-2002
+ *
+ *             991129: -  Bug fix with grio mode
+ *		       - a better sing. AvgQ mode with Grio(WRED)
+ *		       - A finer grained VQ dequeue based on sugestion
+ *		         from Ren Liu
+ *		       - More error checks
+ *
+ *  For all the glorious comments look at include/net/red.h
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <net/pkt_sched.h>
+#include <net/red.h>
+
+#define GRED_DEF_PRIO (MAX_DPs / 2)
+#define GRED_VQ_MASK (MAX_DPs - 1)
+
+struct gred_sched_data;
+struct gred_sched;
+
+struct gred_sched_data {
+	u32		limit;		/* HARD maximal queue length	*/
+	u32		DP;		/* the drop parameters */
+	u32		bytesin;	/* bytes seen on virtualQ so far*/
+	u32		packetsin;	/* packets seen on virtualQ so far*/
+	u32		backlog;	/* bytes on the virtualQ */
+	u8		prio;		/* the prio of this vq */
+
+	struct red_parms parms;
+	struct red_vars  vars;
+	struct red_stats stats;
+};
+
+enum {
+	GRED_WRED_MODE = 1,
+	GRED_RIO_MODE,
+};
+
+struct gred_sched {
+	struct gred_sched_data *tab[MAX_DPs];
+	unsigned long	flags;
+	u32		red_flags;
+	u32 		DPs;
+	u32 		def;
+	struct red_vars wred_set;
+};
+
+static inline int gred_wred_mode(struct gred_sched *table)
+{
+	return test_bit(GRED_WRED_MODE, &table->flags);
+}
+
+static inline void gred_enable_wred_mode(struct gred_sched *table)
+{
+	__set_bit(GRED_WRED_MODE, &table->flags);
+}
+
+static inline void gred_disable_wred_mode(struct gred_sched *table)
+{
+	__clear_bit(GRED_WRED_MODE, &table->flags);
+}
+
+static inline int gred_rio_mode(struct gred_sched *table)
+{
+	return test_bit(GRED_RIO_MODE, &table->flags);
+}
+
+static inline void gred_enable_rio_mode(struct gred_sched *table)
+{
+	__set_bit(GRED_RIO_MODE, &table->flags);
+}
+
+static inline void gred_disable_rio_mode(struct gred_sched *table)
+{
+	__clear_bit(GRED_RIO_MODE, &table->flags);
+}
+
+static inline int gred_wred_mode_check(struct Qdisc *sch)
+{
+	struct gred_sched *table = qdisc_priv(sch);
+	int i;
+
+	/* Really ugly O(n^2) but shouldn't be necessary too frequent. */
+	for (i = 0; i < table->DPs; i++) {
+		struct gred_sched_data *q = table->tab[i];
+		int n;
+
+		if (q == NULL)
+			continue;
+
+		for (n = i + 1; n < table->DPs; n++)
+			if (table->tab[n] && table->tab[n]->prio == q->prio)
+				return 1;
+	}
+
+	return 0;
+}
+
+static inline unsigned int gred_backlog(struct gred_sched *table,
+					struct gred_sched_data *q,
+					struct Qdisc *sch)
+{
+	if (gred_wred_mode(table))
+		return sch->qstats.backlog;
+	else
+		return q->backlog;
+}
+
+static inline u16 tc_index_to_dp(struct sk_buff *skb)
+{
+	return skb->tc_index & GRED_VQ_MASK;
+}
+
+static inline void gred_load_wred_set(const struct gred_sched *table,
+				      struct gred_sched_data *q)
+{
+	q->vars.qavg = table->wred_set.qavg;
+	q->vars.qidlestart = table->wred_set.qidlestart;
+}
+
+static inline void gred_store_wred_set(struct gred_sched *table,
+				       struct gred_sched_data *q)
+{
+	table->wred_set.qavg = q->vars.qavg;
+	table->wred_set.qidlestart = q->vars.qidlestart;
+}
+
+static inline int gred_use_ecn(struct gred_sched *t)
+{
+	return t->red_flags & TC_RED_ECN;
+}
+
+static inline int gred_use_harddrop(struct gred_sched *t)
+{
+	return t->red_flags & TC_RED_HARDDROP;
+}
+
+static int gred_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+	struct gred_sched_data *q = NULL;
+	struct gred_sched *t = qdisc_priv(sch);
+	unsigned long qavg = 0;
+	u16 dp = tc_index_to_dp(skb);
+
+	if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+		dp = t->def;
+
+		q = t->tab[dp];
+		if (!q) {
+			/* Pass through packets not assigned to a DP
+			 * if no default DP has been configured. This
+			 * allows for DP flows to be left untouched.
+			 */
+			if (skb_queue_len(&sch->q) < qdisc_dev(sch)->tx_queue_len)
+				return qdisc_enqueue_tail(skb, sch);
+			else
+				goto drop;
+		}
+
+		/* fix tc_index? --could be controversial but needed for
+		   requeueing */
+		skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
+	}
+
+	/* sum up all the qaves of prios < ours to get the new qave */
+	if (!gred_wred_mode(t) && gred_rio_mode(t)) {
+		int i;
+
+		for (i = 0; i < t->DPs; i++) {
+			if (t->tab[i] && t->tab[i]->prio < q->prio &&
+			    !red_is_idling(&t->tab[i]->vars))
+				qavg += t->tab[i]->vars.qavg;
+		}
+
+	}
+
+	q->packetsin++;
+	q->bytesin += qdisc_pkt_len(skb);
+
+	if (gred_wred_mode(t))
+		gred_load_wred_set(t, q);
+
+	q->vars.qavg = red_calc_qavg(&q->parms,
+				     &q->vars,
+				     gred_backlog(t, q, sch));
+
+	if (red_is_idling(&q->vars))
+		red_end_of_idle_period(&q->vars);
+
+	if (gred_wred_mode(t))
+		gred_store_wred_set(t, q);
+
+	switch (red_action(&q->parms, &q->vars, q->vars.qavg + qavg)) {
+	case RED_DONT_MARK:
+		break;
+
+	case RED_PROB_MARK:
+		qdisc_qstats_overlimit(sch);
+		if (!gred_use_ecn(t) || !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 (gred_use_harddrop(t) || !gred_use_ecn(t) ||
+		    !INET_ECN_set_ce(skb)) {
+			q->stats.forced_drop++;
+			goto congestion_drop;
+		}
+		q->stats.forced_mark++;
+		break;
+	}
+
+	if (gred_backlog(t, q, sch) + qdisc_pkt_len(skb) <= q->limit) {
+		q->backlog += qdisc_pkt_len(skb);
+		return qdisc_enqueue_tail(skb, sch);
+	}
+
+	q->stats.pdrop++;
+drop:
+	return qdisc_drop(skb, sch);
+
+congestion_drop:
+	qdisc_drop(skb, sch);
+	return NET_XMIT_CN;
+}
+
+static struct sk_buff *gred_dequeue(struct Qdisc *sch)
+{
+	struct sk_buff *skb;
+	struct gred_sched *t = qdisc_priv(sch);
+
+	skb = qdisc_dequeue_head(sch);
+
+	if (skb) {
+		struct gred_sched_data *q;
+		u16 dp = tc_index_to_dp(skb);
+
+		if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+			net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x after dequeue, screwing up backlog\n",
+					     tc_index_to_dp(skb));
+		} else {
+			q->backlog -= qdisc_pkt_len(skb);
+
+			if (gred_wred_mode(t)) {
+				if (!sch->qstats.backlog)
+					red_start_of_idle_period(&t->wred_set);
+			} else {
+				if (!q->backlog)
+					red_start_of_idle_period(&q->vars);
+			}
+		}
+
+		return skb;
+	}
+
+	return NULL;
+}
+
+static unsigned int gred_drop(struct Qdisc *sch)
+{
+	struct sk_buff *skb;
+	struct gred_sched *t = qdisc_priv(sch);
+
+	skb = qdisc_dequeue_tail(sch);
+	if (skb) {
+		unsigned int len = qdisc_pkt_len(skb);
+		struct gred_sched_data *q;
+		u16 dp = tc_index_to_dp(skb);
+
+		if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+			net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x while dropping, screwing up backlog\n",
+					     tc_index_to_dp(skb));
+		} else {
+			q->backlog -= len;
+			q->stats.other++;
+
+			if (gred_wred_mode(t)) {
+				if (!sch->qstats.backlog)
+					red_start_of_idle_period(&t->wred_set);
+			} else {
+				if (!q->backlog)
+					red_start_of_idle_period(&q->vars);
+			}
+		}
+
+		qdisc_drop(skb, sch);
+		return len;
+	}
+
+	return 0;
+}
+
+static void gred_reset(struct Qdisc *sch)
+{
+	int i;
+	struct gred_sched *t = qdisc_priv(sch);
+
+	qdisc_reset_queue(sch);
+
+	for (i = 0; i < t->DPs; i++) {
+		struct gred_sched_data *q = t->tab[i];
+
+		if (!q)
+			continue;
+
+		red_restart(&q->vars);
+		q->backlog = 0;
+	}
+}
+
+static inline void gred_destroy_vq(struct gred_sched_data *q)
+{
+	kfree(q);
+}
+
+static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
+{
+	struct gred_sched *table = qdisc_priv(sch);
+	struct tc_gred_sopt *sopt;
+	int i;
+
+	if (dps == NULL)
+		return -EINVAL;
+
+	sopt = nla_data(dps);
+
+	if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
+		return -EINVAL;
+
+	sch_tree_lock(sch);
+	table->DPs = sopt->DPs;
+	table->def = sopt->def_DP;
+	table->red_flags = sopt->flags;
+
+	/*
+	 * Every entry point to GRED is synchronized with the above code
+	 * and the DP is checked against DPs, i.e. shadowed VQs can no
+	 * longer be found so we can unlock right here.
+	 */
+	sch_tree_unlock(sch);
+
+	if (sopt->grio) {
+		gred_enable_rio_mode(table);
+		gred_disable_wred_mode(table);
+		if (gred_wred_mode_check(sch))
+			gred_enable_wred_mode(table);
+	} else {
+		gred_disable_rio_mode(table);
+		gred_disable_wred_mode(table);
+	}
+
+	for (i = table->DPs; i < MAX_DPs; i++) {
+		if (table->tab[i]) {
+			pr_warn("GRED: Warning: Destroying shadowed VQ 0x%x\n",
+				i);
+			gred_destroy_vq(table->tab[i]);
+			table->tab[i] = NULL;
+		}
+	}
+
+	return 0;
+}
+
+static inline int gred_change_vq(struct Qdisc *sch, int dp,
+				 struct tc_gred_qopt *ctl, int prio,
+				 u8 *stab, u32 max_P,
+				 struct gred_sched_data **prealloc)
+{
+	struct gred_sched *table = qdisc_priv(sch);
+	struct gred_sched_data *q = table->tab[dp];
+
+	if (!q) {
+		table->tab[dp] = q = *prealloc;
+		*prealloc = NULL;
+		if (!q)
+			return -ENOMEM;
+	}
+
+	q->DP = dp;
+	q->prio = prio;
+	q->limit = ctl->limit;
+
+	if (q->backlog == 0)
+		red_end_of_idle_period(&q->vars);
+
+	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);
+	return 0;
+}
+
+static const struct nla_policy gred_policy[TCA_GRED_MAX + 1] = {
+	[TCA_GRED_PARMS]	= { .len = sizeof(struct tc_gred_qopt) },
+	[TCA_GRED_STAB]		= { .len = 256 },
+	[TCA_GRED_DPS]		= { .len = sizeof(struct tc_gred_sopt) },
+	[TCA_GRED_MAX_P]	= { .type = NLA_U32 },
+};
+
+static int gred_change(struct Qdisc *sch, struct nlattr *opt)
+{
+	struct gred_sched *table = qdisc_priv(sch);
+	struct tc_gred_qopt *ctl;
+	struct nlattr *tb[TCA_GRED_MAX + 1];
+	int err, prio = GRED_DEF_PRIO;
+	u8 *stab;
+	u32 max_P;
+	struct gred_sched_data *prealloc;
+
+	if (opt == NULL)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
+		return gred_change_table_def(sch, opt);
+
+	if (tb[TCA_GRED_PARMS] == NULL ||
+	    tb[TCA_GRED_STAB] == NULL)
+		return -EINVAL;
+
+	max_P = tb[TCA_GRED_MAX_P] ? nla_get_u32(tb[TCA_GRED_MAX_P]) : 0;
+
+	err = -EINVAL;
+	ctl = nla_data(tb[TCA_GRED_PARMS]);
+	stab = nla_data(tb[TCA_GRED_STAB]);
+
+	if (ctl->DP >= table->DPs)
+		goto errout;
+
+	if (gred_rio_mode(table)) {
+		if (ctl->prio == 0) {
+			int def_prio = GRED_DEF_PRIO;
+
+			if (table->tab[table->def])
+				def_prio = table->tab[table->def]->prio;
+
+			printk(KERN_DEBUG "GRED: DP %u does not have a prio "
+			       "setting default to %d\n", ctl->DP, def_prio);
+
+			prio = def_prio;
+		} else
+			prio = ctl->prio;
+	}
+
+	prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
+	sch_tree_lock(sch);
+
+	err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc);
+	if (err < 0)
+		goto errout_locked;
+
+	if (gred_rio_mode(table)) {
+		gred_disable_wred_mode(table);
+		if (gred_wred_mode_check(sch))
+			gred_enable_wred_mode(table);
+	}
+
+	err = 0;
+
+errout_locked:
+	sch_tree_unlock(sch);
+	kfree(prealloc);
+errout:
+	return err;
+}
+
+static int gred_init(struct Qdisc *sch, struct nlattr *opt)
+{
+	struct nlattr *tb[TCA_GRED_MAX + 1];
+	int err;
+
+	if (opt == NULL)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
+		return -EINVAL;
+
+	return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
+}
+
+static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct gred_sched *table = qdisc_priv(sch);
+	struct nlattr *parms, *opts = NULL;
+	int i;
+	u32 max_p[MAX_DPs];
+	struct tc_gred_sopt sopt = {
+		.DPs	= table->DPs,
+		.def_DP	= table->def,
+		.grio	= gred_rio_mode(table),
+		.flags	= table->red_flags,
+	};
+
+	opts = nla_nest_start(skb, TCA_OPTIONS);
+	if (opts == NULL)
+		goto nla_put_failure;
+	if (nla_put(skb, TCA_GRED_DPS, sizeof(sopt), &sopt))
+		goto nla_put_failure;
+
+	for (i = 0; i < MAX_DPs; i++) {
+		struct gred_sched_data *q = table->tab[i];
+
+		max_p[i] = q ? q->parms.max_P : 0;
+	}
+	if (nla_put(skb, TCA_GRED_MAX_P, sizeof(max_p), max_p))
+		goto nla_put_failure;
+
+	parms = nla_nest_start(skb, TCA_GRED_PARMS);
+	if (parms == NULL)
+		goto nla_put_failure;
+
+	for (i = 0; i < MAX_DPs; i++) {
+		struct gred_sched_data *q = table->tab[i];
+		struct tc_gred_qopt opt;
+		unsigned long qavg;
+
+		memset(&opt, 0, sizeof(opt));
+
+		if (!q) {
+			/* hack -- fix at some point with proper message
+			   This is how we indicate to tc that there is no VQ
+			   at this DP */
+
+			opt.DP = MAX_DPs + i;
+			goto append_opt;
+		}
+
+		opt.limit	= q->limit;
+		opt.DP		= q->DP;
+		opt.backlog	= gred_backlog(table, q, sch);
+		opt.prio	= q->prio;
+		opt.qth_min	= q->parms.qth_min >> q->parms.Wlog;
+		opt.qth_max	= q->parms.qth_max >> q->parms.Wlog;
+		opt.Wlog	= q->parms.Wlog;
+		opt.Plog	= q->parms.Plog;
+		opt.Scell_log	= q->parms.Scell_log;
+		opt.other	= q->stats.other;
+		opt.early	= q->stats.prob_drop;
+		opt.forced	= q->stats.forced_drop;
+		opt.pdrop	= q->stats.pdrop;
+		opt.packets	= q->packetsin;
+		opt.bytesin	= q->bytesin;
+
+		if (gred_wred_mode(table))
+			gred_load_wred_set(table, q);
+
+		qavg = red_calc_qavg(&q->parms, &q->vars,
+				     q->vars.qavg >> q->parms.Wlog);
+		opt.qave = qavg >> q->parms.Wlog;
+
+append_opt:
+		if (nla_append(skb, sizeof(opt), &opt) < 0)
+			goto nla_put_failure;
+	}
+
+	nla_nest_end(skb, parms);
+
+	return nla_nest_end(skb, opts);
+
+nla_put_failure:
+	nla_nest_cancel(skb, opts);
+	return -EMSGSIZE;
+}
+
+static void gred_destroy(struct Qdisc *sch)
+{
+	struct gred_sched *table = qdisc_priv(sch);
+	int i;
+
+	for (i = 0; i < table->DPs; i++) {
+		if (table->tab[i])
+			gred_destroy_vq(table->tab[i]);
+	}
+}
+
+static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
+	.id		=	"gred",
+	.priv_size	=	sizeof(struct gred_sched),
+	.enqueue	=	gred_enqueue,
+	.dequeue	=	gred_dequeue,
+	.peek		=	qdisc_peek_head,
+	.drop		=	gred_drop,
+	.init		=	gred_init,
+	.reset		=	gred_reset,
+	.destroy	=	gred_destroy,
+	.change		=	gred_change,
+	.dump		=	gred_dump,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init gred_module_init(void)
+{
+	return register_qdisc(&gred_qdisc_ops);
+}
+
+static void __exit gred_module_exit(void)
+{
+	unregister_qdisc(&gred_qdisc_ops);
+}
+
+module_init(gred_module_init)
+module_exit(gred_module_exit)
+
+MODULE_LICENSE("GPL");