1 files changed, 543 insertions, 0 deletions
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
new file mode 100644
index 00000000000..cb9711ea8c6
--- /dev/null
+++ b/net/sched/sch_tbf.c
@@ -0,0 +1,543 @@
+/*
+ * net/sched/sch_tbf.c	Token Bucket Filter 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>
+ *		Dmitry Torokhov <dtor@mail.ru> - allow attaching inner qdiscs -
+ *						 original idea by Martin Devera
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/in.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/if_ether.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/notifier.h>
+#include <net/ip.h>
+#include <net/route.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/pkt_sched.h>
+
+
+/*	Simple Token Bucket Filter.
+	=======================================
+
+	SOURCE.
+	-------
+
+	None.
+
+	Description.
+	------------
+
+	A data flow obeys TBF with rate R and depth B, if for any
+	time interval t_i...t_f the number of transmitted bits
+	does not exceed B + R*(t_f-t_i).
+
+	Packetized version of this definition:
+	The sequence of packets of sizes s_i served at moments t_i
+	obeys TBF, if for any i<=k:
+
+	s_i+....+s_k <= B + R*(t_k - t_i)
+
+	Algorithm.
+	----------
+
+	Let N(t_i) be B/R initially and N(t) grow continuously with time as:
+
+	N(t+delta) = min{B/R, N(t) + delta}
+
+	If the first packet in queue has length S, it may be
+	transmitted only at the time t_* when S/R <= N(t_*),
+	and in this case N(t) jumps:
+
+	N(t_* + 0) = N(t_* - 0) - S/R.
+
+
+
+	Actually, QoS requires two TBF to be applied to a data stream.
+	One of them controls steady state burst size, another
+	one with rate P (peak rate) and depth M (equal to link MTU)
+	limits bursts at a smaller time scale.
+
+	It is easy to see that P>R, and B>M. If P is infinity, this double
+	TBF is equivalent to a single one.
+
+	When TBF works in reshaping mode, latency is estimated as:
+
+	lat = max ((L-B)/R, (L-M)/P)
+
+
+	NOTES.
+	------
+
+	If TBF throttles, it starts a watchdog timer, which will wake it up
+	when it is ready to transmit.
+	Note that the minimal timer resolution is 1/HZ.
+	If no new packets arrive during this period,
+	or if the device is not awaken by EOI for some previous packet,
+	TBF can stop its activity for 1/HZ.
+
+
+	This means, that with depth B, the maximal rate is
+
+	R_crit = B*HZ
+
+	F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes.
+
+	Note that the peak rate TBF is much more tough: with MTU 1500
+	P_crit = 150Kbytes/sec. So, if you need greater peak
+	rates, use alpha with HZ=1000 :-)
+
+	With classful TBF, limit is just kept for backwards compatibility.
+	It is passed to the default bfifo qdisc - if the inner qdisc is
+	changed the limit is not effective anymore.
+*/
+
+struct tbf_sched_data
+{
+/* Parameters */
+	u32		limit;		/* Maximal length of backlog: bytes */
+	u32		buffer;		/* Token bucket depth/rate: MUST BE >= MTU/B */
+	u32		mtu;
+	u32		max_size;
+	struct qdisc_rate_table	*R_tab;
+	struct qdisc_rate_table	*P_tab;
+
+/* Variables */
+	long	tokens;			/* Current number of B tokens */
+	long	ptokens;		/* Current number of P tokens */
+	psched_time_t	t_c;		/* Time check-point */
+	struct timer_list wd_timer;	/* Watchdog timer */
+	struct Qdisc	*qdisc;		/* Inner qdisc, default - bfifo queue */
+};
+
+#define L2T(q,L)   ((q)->R_tab->data[(L)>>(q)->R_tab->rate.cell_log])
+#define L2T_P(q,L) ((q)->P_tab->data[(L)>>(q)->P_tab->rate.cell_log])
+
+static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	int ret;
+
+	if (skb->len > q->max_size) {
+		sch->qstats.drops++;
+#ifdef CONFIG_NET_CLS_POLICE
+		if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
+#endif
+			kfree_skb(skb);
+
+		return NET_XMIT_DROP;
+	}
+
+	if ((ret = q->qdisc->enqueue(skb, q->qdisc)) != 0) {
+		sch->qstats.drops++;
+		return ret;
+	}
+
+	sch->q.qlen++;
+	sch->bstats.bytes += skb->len;
+	sch->bstats.packets++;
+	return 0;
+}
+
+static int tbf_requeue(struct sk_buff *skb, struct Qdisc* sch)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	int ret;
+
+	if ((ret = q->qdisc->ops->requeue(skb, q->qdisc)) == 0) {
+		sch->q.qlen++;
+		sch->qstats.requeues++;
+	}
+
+	return ret;
+}
+
+static unsigned int tbf_drop(struct Qdisc* sch)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	unsigned int len;
+
+	if ((len = q->qdisc->ops->drop(q->qdisc)) != 0) {
+		sch->q.qlen--;
+		sch->qstats.drops++;
+	}
+	return len;
+}
+
+static void tbf_watchdog(unsigned long arg)
+{
+	struct Qdisc *sch = (struct Qdisc*)arg;
+
+	sch->flags &= ~TCQ_F_THROTTLED;
+	netif_schedule(sch->dev);
+}
+
+static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb;
+
+	skb = q->qdisc->dequeue(q->qdisc);
+
+	if (skb) {
+		psched_time_t now;
+		long toks, delay;
+		long ptoks = 0;
+		unsigned int len = skb->len;
+
+		PSCHED_GET_TIME(now);
+
+		toks = PSCHED_TDIFF_SAFE(now, q->t_c, q->buffer);
+
+		if (q->P_tab) {
+			ptoks = toks + q->ptokens;
+			if (ptoks > (long)q->mtu)
+				ptoks = q->mtu;
+			ptoks -= L2T_P(q, len);
+		}
+		toks += q->tokens;
+		if (toks > (long)q->buffer)
+			toks = q->buffer;
+		toks -= L2T(q, len);
+
+		if ((toks|ptoks) >= 0) {
+			q->t_c = now;
+			q->tokens = toks;
+			q->ptokens = ptoks;
+			sch->q.qlen--;
+			sch->flags &= ~TCQ_F_THROTTLED;
+			return skb;
+		}
+
+		delay = PSCHED_US2JIFFIE(max_t(long, -toks, -ptoks));
+
+		if (delay == 0)
+			delay = 1;
+
+		mod_timer(&q->wd_timer, jiffies+delay);
+
+		/* Maybe we have a shorter packet in the queue,
+		   which can be sent now. It sounds cool,
+		   but, however, this is wrong in principle.
+		   We MUST NOT reorder packets under these circumstances.
+
+		   Really, if we split the flow into independent
+		   subflows, it would be a very good solution.
+		   This is the main idea of all FQ algorithms
+		   (cf. CSZ, HPFQ, HFSC)
+		 */
+
+		if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) {
+			/* When requeue fails skb is dropped */
+			sch->q.qlen--;
+			sch->qstats.drops++;
+		}
+
+		sch->flags |= TCQ_F_THROTTLED;
+		sch->qstats.overlimits++;
+	}
+	return NULL;
+}
+
+static void tbf_reset(struct Qdisc* sch)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+
+	qdisc_reset(q->qdisc);
+	sch->q.qlen = 0;
+	PSCHED_GET_TIME(q->t_c);
+	q->tokens = q->buffer;
+	q->ptokens = q->mtu;
+	sch->flags &= ~TCQ_F_THROTTLED;
+	del_timer(&q->wd_timer);
+}
+
+static struct Qdisc *tbf_create_dflt_qdisc(struct net_device *dev, u32 limit)
+{
+	struct Qdisc *q = qdisc_create_dflt(dev, &bfifo_qdisc_ops);
+        struct rtattr *rta;
+	int ret;
+
+	if (q) {
+		rta = kmalloc(RTA_LENGTH(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
+		if (rta) {
+			rta->rta_type = RTM_NEWQDISC;
+			rta->rta_len = RTA_LENGTH(sizeof(struct tc_fifo_qopt)); 
+			((struct tc_fifo_qopt *)RTA_DATA(rta))->limit = limit;
+
+			ret = q->ops->change(q, rta);
+			kfree(rta);
+
+			if (ret == 0)
+				return q;
+		}
+		qdisc_destroy(q);
+	}
+
+	return NULL;
+}
+
+static int tbf_change(struct Qdisc* sch, struct rtattr *opt)
+{
+	int err = -EINVAL;
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	struct rtattr *tb[TCA_TBF_PTAB];
+	struct tc_tbf_qopt *qopt;
+	struct qdisc_rate_table *rtab = NULL;
+	struct qdisc_rate_table *ptab = NULL;
+	struct Qdisc *child = NULL;
+	int max_size,n;
+
+	if (rtattr_parse_nested(tb, TCA_TBF_PTAB, opt) ||
+	    tb[TCA_TBF_PARMS-1] == NULL ||
+	    RTA_PAYLOAD(tb[TCA_TBF_PARMS-1]) < sizeof(*qopt))
+		goto done;
+
+	qopt = RTA_DATA(tb[TCA_TBF_PARMS-1]);
+	rtab = qdisc_get_rtab(&qopt->rate, tb[TCA_TBF_RTAB-1]);
+	if (rtab == NULL)
+		goto done;
+
+	if (qopt->peakrate.rate) {
+		if (qopt->peakrate.rate > qopt->rate.rate)
+			ptab = qdisc_get_rtab(&qopt->peakrate, tb[TCA_TBF_PTAB-1]);
+		if (ptab == NULL)
+			goto done;
+	}
+
+	for (n = 0; n < 256; n++)
+		if (rtab->data[n] > qopt->buffer) break;
+	max_size = (n << qopt->rate.cell_log)-1;
+	if (ptab) {
+		int size;
+
+		for (n = 0; n < 256; n++)
+			if (ptab->data[n] > qopt->mtu) break;
+		size = (n << qopt->peakrate.cell_log)-1;
+		if (size < max_size) max_size = size;
+	}
+	if (max_size < 0)
+		goto done;
+
+	if (q->qdisc == &noop_qdisc) {
+		if ((child = tbf_create_dflt_qdisc(sch->dev, qopt->limit)) == NULL)
+			goto done;
+	}
+
+	sch_tree_lock(sch);
+	if (child) q->qdisc = child;
+	q->limit = qopt->limit;
+	q->mtu = qopt->mtu;
+	q->max_size = max_size;
+	q->buffer = qopt->buffer;
+	q->tokens = q->buffer;
+	q->ptokens = q->mtu;
+	rtab = xchg(&q->R_tab, rtab);
+	ptab = xchg(&q->P_tab, ptab);
+	sch_tree_unlock(sch);
+	err = 0;
+done:
+	if (rtab)
+		qdisc_put_rtab(rtab);
+	if (ptab)
+		qdisc_put_rtab(ptab);
+	return err;
+}
+
+static int tbf_init(struct Qdisc* sch, struct rtattr *opt)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+
+	if (opt == NULL)
+		return -EINVAL;
+
+	PSCHED_GET_TIME(q->t_c);
+	init_timer(&q->wd_timer);
+	q->wd_timer.function = tbf_watchdog;
+	q->wd_timer.data = (unsigned long)sch;
+
+	q->qdisc = &noop_qdisc;
+
+	return tbf_change(sch, opt);
+}
+
+static void tbf_destroy(struct Qdisc *sch)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+
+	del_timer(&q->wd_timer);
+
+	if (q->P_tab)
+		qdisc_put_rtab(q->P_tab);
+	if (q->R_tab)
+		qdisc_put_rtab(q->R_tab);
+
+	qdisc_destroy(q->qdisc);
+}
+
+static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	unsigned char	 *b = skb->tail;
+	struct rtattr *rta;
+	struct tc_tbf_qopt opt;
+
+	rta = (struct rtattr*)b;
+	RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
+
+	opt.limit = q->limit;
+	opt.rate = q->R_tab->rate;
+	if (q->P_tab)
+		opt.peakrate = q->P_tab->rate;
+	else
+		memset(&opt.peakrate, 0, sizeof(opt.peakrate));
+	opt.mtu = q->mtu;
+	opt.buffer = q->buffer;
+	RTA_PUT(skb, TCA_TBF_PARMS, sizeof(opt), &opt);
+	rta->rta_len = skb->tail - b;
+
+	return skb->len;
+
+rtattr_failure:
+	skb_trim(skb, b - skb->data);
+	return -1;
+}
+
+static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
+			  struct sk_buff *skb, struct tcmsg *tcm)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+
+	if (cl != 1) 	/* only one class */
+		return -ENOENT;
+
+	tcm->tcm_handle |= TC_H_MIN(1);
+	tcm->tcm_info = q->qdisc->handle;
+
+	return 0;
+}
+
+static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
+		     struct Qdisc **old)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+
+	if (new == NULL)
+		new = &noop_qdisc;
+
+	sch_tree_lock(sch);
+	*old = xchg(&q->qdisc, new);
+	qdisc_reset(*old);
+	sch->q.qlen = 0;
+	sch_tree_unlock(sch);
+
+	return 0;
+}
+
+static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
+{
+	struct tbf_sched_data *q = qdisc_priv(sch);
+	return q->qdisc;
+}
+
+static unsigned long tbf_get(struct Qdisc *sch, u32 classid)
+{
+	return 1;
+}
+
+static void tbf_put(struct Qdisc *sch, unsigned long arg)
+{
+}
+
+static int tbf_change_class(struct Qdisc *sch, u32 classid, u32 parentid, 
+			    struct rtattr **tca, unsigned long *arg)
+{
+	return -ENOSYS;
+}
+
+static int tbf_delete(struct Qdisc *sch, unsigned long arg)
+{
+	return -ENOSYS;
+}
+
+static void tbf_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 **tbf_find_tcf(struct Qdisc *sch, unsigned long cl)
+{
+	return NULL;
+}
+
+static struct Qdisc_class_ops tbf_class_ops =
+{
+	.graft		=	tbf_graft,
+	.leaf		=	tbf_leaf,
+	.get		=	tbf_get,
+	.put		=	tbf_put,
+	.change		=	tbf_change_class,
+	.delete		=	tbf_delete,
+	.walk		=	tbf_walk,
+	.tcf_chain	=	tbf_find_tcf,
+	.dump		=	tbf_dump_class,
+};
+
+static struct Qdisc_ops tbf_qdisc_ops = {
+	.next		=	NULL,
+	.cl_ops		=	&tbf_class_ops,
+	.id		=	"tbf",
+	.priv_size	=	sizeof(struct tbf_sched_data),
+	.enqueue	=	tbf_enqueue,
+	.dequeue	=	tbf_dequeue,
+	.requeue	=	tbf_requeue,
+	.drop		=	tbf_drop,
+	.init		=	tbf_init,
+	.reset		=	tbf_reset,
+	.destroy	=	tbf_destroy,
+	.change		=	tbf_change,
+	.dump		=	tbf_dump,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init tbf_module_init(void)
+{
+	return register_qdisc(&tbf_qdisc_ops);
+}
+
+static void __exit tbf_module_exit(void)
+{
+	unregister_qdisc(&tbf_qdisc_ops);
+}
+module_init(tbf_module_init)
+module_exit(tbf_module_exit)
+MODULE_LICENSE("GPL");