On Thu, Mar 18, 2004 at 12:58:58PM -0800, Stephen Hemminger wrote:
[...]
> A trivial example is:
> tc qdisc add dev eth0 root delay latency 25ms rate 100mbit
great to see Linux will begins to have a DummyNet replacement
some weeks ago I had to use FreeBSD for this task
btw, can this work in bridge mode? (like DummyNet)
Ulisses
> +++ b/net/sched/Kconfig Thu Mar 18 12:04:02 2004
> @@ -164,6 +164,17 @@
> To compile this code as a module, choose M here: the
> module will be called sch_dsmark.
>
> +config NET_SCH_DELAY
> + tristate "Delay simulator"
> + depends on NET_SCHED
> + help
> + Say Y if you want to delay packets by a fixed amount of
> + time. This is often useful to simulate network delay when
> + testing applications or protocols.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called sch_delay.
> +
> config NET_SCH_INGRESS
> tristate "Ingress Qdisc"
> depends on NET_SCHED && NETFILTER
> diff -Nru a/net/sched/Makefile b/net/sched/Makefile
> --- a/net/sched/Makefile Thu Mar 18 12:04:02 2004
> +++ b/net/sched/Makefile Thu Mar 18 12:04:02 2004
> @@ -22,6 +22,7 @@
> obj-$(CONFIG_NET_SCH_TEQL) += sch_teql.o
> obj-$(CONFIG_NET_SCH_PRIO) += sch_prio.o
> obj-$(CONFIG_NET_SCH_ATM) += sch_atm.o
> +obj-$(CONFIG_NET_SCH_DELAY) += sch_delay.o
> obj-$(CONFIG_NET_CLS_U32) += cls_u32.o
> obj-$(CONFIG_NET_CLS_ROUTE4) += cls_route.o
> obj-$(CONFIG_NET_CLS_FW) += cls_fw.o
> diff -Nru a/net/sched/sch_delay.c b/net/sched/sch_delay.c
> --- /dev/null Wed Dec 31 16:00:00 1969
> +++ b/net/sched/sch_delay.c Thu Mar 18 12:04:02 2004
> @@ -0,0 +1,269 @@
> +/*
> + * net/sched/sch_delay.c Simple constant delay
> + *
> + * 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: Stephen Hemminger <shemminger@osdl.org>
> + */
> +
> +#include <linux/config.h>
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/kernel.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>
> +
> +/* Network delay simulator
> + This scheduler adds a fixed delay to all packets.
> + Similar to NISTnet and BSD Dummynet.
> +
> + It uses byte fifo underneath similar to TBF */
> +struct dly_sched_data {
> + u32 latency;
> + u32 limit;
> + struct timer_list timer;
> + struct Qdisc *qdisc;
> +};
> +
> +/* Time stamp put into socket buffer control block */
> +struct dly_skb_cb {
> + psched_time_t queuetime;
> +};
> +
> +/* Enqueue packets with underlying discipline (fifo)
> + * but mark them with current time first.
> + */
> +static int dly_enqueue(struct sk_buff *skb, struct Qdisc *sch)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> + struct dly_skb_cb *cb = (struct dly_skb_cb *)skb->cb;
> + int ret;
> +
> + PSCHED_GET_TIME(cb->queuetime);
> +
> + /* Queue to underlying scheduler */
> + ret = q->qdisc->enqueue(skb, q->qdisc);
> + if (ret)
> + sch->stats.drops++;
> + else {
> + sch->q.qlen++;
> + sch->stats.bytes += skb->len;
> + sch->stats.packets++;
> + }
> + return 0;
> +}
> +
> +/* Requeue packets but don't change time stamp */
> +static int dly_requeue(struct sk_buff *skb, struct Qdisc *sch)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> + int ret;
> +
> + ret = q->qdisc->ops->requeue(skb, q->qdisc);
> + if (ret == 0)
> + sch->q.qlen++;
> + return ret;
> +}
> +
> +static unsigned int dly_drop(struct Qdisc *sch)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> + unsigned int len;
> +
> + len = q->qdisc->ops->drop(q->qdisc);
> + if (len) {
> + sch->q.qlen--;
> + sch->stats.drops++;
> + }
> + return len;
> +}
> +
> +/* Dequeue packet.
> + * If packet needs to be held up, then stop the
> + * queue and set timer to wakeup later.
> + */
> +static struct sk_buff *dly_dequeue(struct Qdisc *sch)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> + struct sk_buff *skb = q->qdisc->dequeue(q->qdisc);
> +
> + if (skb) {
> + struct dly_skb_cb *cb = (struct dly_skb_cb *)skb->cb;
> + psched_time_t now;
> + long diff;
> +
> + PSCHED_GET_TIME(now);
> + diff = q->latency - PSCHED_TDIFF(now, cb->queuetime);
> +
> + if (diff <= 0) {
> + sch->q.qlen--;
> + sch->flags &= ~TCQ_F_THROTTLED;
> + return skb;
> + }
> +
> + if (!netif_queue_stopped(sch->dev)) {
> + long delay = PSCHED_US2JIFFIE(diff);
> + if (delay <= 0)
> + delay = 1;
> + mod_timer(&q->timer, jiffies+delay);
> + }
> +
> + if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) {
> + sch->q.qlen--;
> + sch->stats.drops++;
> + }
> + sch->flags |= TCQ_F_THROTTLED;
> + }
> + return NULL;
> +}
> +
> +static void dly_reset(struct Qdisc *sch)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> +
> + qdisc_reset(q->qdisc);
> + sch->q.qlen = 0;
> + sch->flags &= ~TCQ_F_THROTTLED;
> + del_timer(&q->timer);
> +}
> +
> +static void dly_timer(unsigned long arg)
> +{
> + struct Qdisc *sch = (struct Qdisc *)arg;
> +
> + sch->flags &= ~TCQ_F_THROTTLED;
> + netif_schedule(sch->dev);
> +}
> +
> +/* Tell Fifo the new limit. */
> +static int change_limit(struct Qdisc *q, u32 limit)
> +{
> + struct rtattr *rta;
> + int ret;
> +
> + rta = kmalloc(RTA_LENGTH(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
> + if (!rta)
> + return -ENOMEM;
> +
> + rta->rta_type = RTM_NEWQDISC;
> + ((struct tc_fifo_qopt *)RTA_DATA(rta))->limit = limit;
> + ret = q->ops->change(q, rta);
> + kfree(rta);
> +
> + return ret;
> +}
> +
> +/* Setup underlying FIFO discipline */
> +static int dly_change(struct Qdisc *sch, struct rtattr *opt)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> + struct tc_dly_qopt *qopt = RTA_DATA(opt);
> + int err;
> +
> + if (q->qdisc == &noop_qdisc) {
> + struct Qdisc *child
> + = qdisc_create_dflt(sch->dev, &bfifo_qdisc_ops);
> + if (!child)
> + return -EINVAL;
> + q->qdisc = child;
> + }
> +
> + err = change_limit(q->qdisc, qopt->limit);
> + if (err) {
> + qdisc_destroy(q->qdisc);
> + q->qdisc = &noop_qdisc;
> + } else {
> + q->latency = qopt->latency;
> + q->limit = qopt->limit;
> + }
> + return err;
> +}
> +
> +static int dly_init(struct Qdisc *sch, struct rtattr *opt)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> +
> + if (!opt)
> + return -EINVAL;
> +
> + init_timer(&q->timer);
> + q->timer.function = dly_timer;
> + q->timer.data = (unsigned long) sch;
> + q->qdisc = &noop_qdisc;
> +
> + return dly_change(sch, opt);
> +}
> +
> +static void dly_destroy(struct Qdisc *sch)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> +
> + del_timer(&q->timer);
> + qdisc_destroy(q->qdisc);
> + q->qdisc = &noop_qdisc;
> +}
> +
> +static int dly_dump(struct Qdisc *sch, struct sk_buff *skb)
> +{
> + struct dly_sched_data *q = (struct dly_sched_data *)sch->data;
> + unsigned char *b = skb->tail;
> + struct tc_dly_qopt qopt;
> +
> + qopt.latency = q->latency;
> + qopt.limit = q->limit;
> +
> + RTA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
> +
> + return skb->len;
> +
> +rtattr_failure:
> + skb_trim(skb, b - skb->data);
> + return -1;
> +}
> +
> +static struct Qdisc_ops dly_qdisc_ops = {
> + .id = "delay",
> + .priv_size = sizeof(struct dly_sched_data),
> + .enqueue = dly_enqueue,
> + .dequeue = dly_dequeue,
> + .requeue = dly_requeue,
> + .drop = dly_drop,
> + .init = dly_init,
> + .reset = dly_reset,
> + .destroy = dly_destroy,
> + .change = dly_change,
> + .dump = dly_dump,
> + .owner = THIS_MODULE,
> +};
> +
> +
> +static int __init dly_module_init(void)
> +{
> + return register_qdisc(&dly_qdisc_ops);
> +}
> +static void __exit dly_module_exit(void)
> +{
> + unregister_qdisc(&dly_qdisc_ops);
> +}
> +module_init(dly_module_init)
> +module_exit(dly_module_exit)
> +MODULE_LICENSE("GPL");
> -
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