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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/sched/sch_tbf.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'net/sched/sch_tbf.c')
-rw-r--r--net/sched/sch_tbf.c543
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 000000000000..cb9711ea8c6c
--- /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");