This patch updates the network emulation packet scheduler.
* name changed from delay to netem since it does more than just delay
* Catalin's merged code to do packet reordering
* uses a socket queue's directly rather than layering on qdisc(fifo)
because this is used in performance tests.
* adds placeholder in API for future enhancements (rate and duplicate).
Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxx>
diff -urNp -X dontdiff linux-2.6/include/linux/pkt_sched.h sched-2.6/include/linux/pkt_sched.h
--- linux-2.6/include/linux/pkt_sched.h 2004-06-24 08:52:58.000000000 -0700
+++ sched-2.6/include/linux/pkt_sched.h 2004-07-01 03:53:31.185482832 -0700
@@ -439,11 +439,14 @@ enum {
#define TCA_ATM_MAX TCA_ATM_STATE
-/* Delay section */
-struct tc_dly_qopt
+/* Network emulator */
+struct tc_netem_qopt
{
- __u32 latency;
- __u32 limit;
- __u32 loss;
+ __u32 latency; /* added delay (us) */
+ __u32 limit; /* fifo limit (packets) */
+ __u32 loss; /* random packet loss (0=none ~0=100%) */
+ __u32 gap; /* re-ordering gap (0 for delay all) */
+ __u32 duplicate; /* random packet dup (0=none ~0=100%) */
+ __u32 rate; /* maximum transmit rate (bytes/sec) */
};
#endif
diff -urNp -X dontdiff linux-2.6/net/sched/Kconfig sched-2.6/net/sched/Kconfig
--- linux-2.6/net/sched/Kconfig 2004-06-25 09:41:00.000000000 -0700
+++ sched-2.6/net/sched/Kconfig 2004-06-28 09:17:19.000000000 -0700
@@ -164,12 +164,12 @@ config NET_SCH_DSMARK
To compile this code as a module, choose M here: the
module will be called sch_dsmark.
-config NET_SCH_DELAY
- tristate "Delay simulator"
+config NET_SCH_NETEM
+ tristate "Network emulator"
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
+ Say Y if you want to emulate network delay, loss, and packet
+ re-ordering. This is often useful to simulate networks when
testing applications or protocols.
To compile this driver as a module, choose M here: the module
diff -urNp -X dontdiff linux-2.6/net/sched/Makefile sched-2.6/net/sched/Makefile
--- linux-2.6/net/sched/Makefile 2004-06-24 08:52:58.000000000 -0700
+++ sched-2.6/net/sched/Makefile 2004-06-28 09:17:49.000000000 -0700
@@ -24,7 +24,7 @@ obj-$(CONFIG_NET_SCH_TBF) += sch_tbf.o
obj-$(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_SCH_NETEM) += sch_netem.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 -urNp -X dontdiff linux-2.6/net/sched/sch_delay.c sched-2.6/net/sched/sch_delay.c
--- linux-2.6/net/sched/sch_delay.c 2004-06-21 09:23:15.000000000 -0700
+++ sched-2.6/net/sched/sch_delay.c 1969-12-31 16:00:00.000000000 -0800
@@ -1,281 +0,0 @@
-/*
- * 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@xxxxxxxx>
- */
-
-#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;
- u32 loss;
- 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;
-
- /* Random packet drop 0 => none, ~0 => all */
- if (q->loss >= net_random()) {
- sch->stats.drops++;
- return 0; /* lie about loss so TCP doesn't know */
- }
-
- 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 ret;
-}
-
-/* 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;
-
- retry:
- 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, delay;
-
- 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 (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) {
- sch->q.qlen--;
- sch->stats.drops++;
- goto retry;
- }
-
- delay = PSCHED_US2JIFFIE(diff);
- if (delay <= 0)
- delay = 1;
- mod_timer(&q->timer, jiffies+delay);
-
- 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;
- 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);
-
- 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;
- q->loss = qopt->loss;
- }
- 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;
- qopt.loss = q->loss;
-
- 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");
diff -urNp -X dontdiff linux-2.6/net/sched/sch_netem.c sched-2.6/net/sched/sch_netem.c
--- linux-2.6/net/sched/sch_netem.c 1969-12-31 16:00:00.000000000 -0800
+++ sched-2.6/net/sched/sch_netem.c 2004-06-30 14:05:13.000000000 -0700
@@ -0,0 +1,255 @@
+/*
+ * net/sched/sch_netem.c Network emulator
+ *
+ * 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@xxxxxxxx>
+ * Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <asm/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+
+#include <net/pkt_sched.h>
+
+/* Network emulator
+ *
+ * This scheduler can alters spacing and order
+ * Similar to NISTnet and BSD Dummynet.
+ */
+
+struct netem_sched_data {
+ struct sk_buff_head qnormal;
+ struct sk_buff_head qdelay;
+ struct timer_list timer;
+
+ u32 latency;
+ u32 loss;
+ u32 counter;
+ u32 gap;
+};
+
+/* Time stamp put into socket buffer control block */
+struct netem_skb_cb {
+ psched_time_t time_to_send;
+};
+
+/* Enqueue packets with underlying discipline (fifo)
+ * but mark them with current time first.
+ */
+static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb;
+
+ pr_debug("netem_enqueue skb=%p @%lu\n", skb, jiffies);
+
+ /* Random packet drop 0 => none, ~0 => all */
+ if (q->loss >= net_random()) {
+ sch->stats.drops++;
+ return 0; /* lie about loss so TCP doesn't know */
+ }
+
+ if (q->qnormal.qlen < sch->dev->tx_queue_len) {
+ PSCHED_GET_TIME(cb->time_to_send);
+ PSCHED_TADD(cb->time_to_send, q->latency);
+
+ __skb_queue_tail(&q->qnormal, skb);
+ sch->q.qlen++;
+ sch->stats.bytes += skb->len;
+ sch->stats.packets++;
+ return 0;
+ }
+
+ sch->stats.drops++;
+ kfree_skb(skb);
+ return NET_XMIT_DROP;
+}
+
+/* Requeue packets but don't change time stamp */
+static int netem_requeue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+
+ __skb_queue_head(&q->qnormal, skb);
+ sch->q.qlen++;
+ return 0;
+}
+
+/*
+ * Check the look aside buffer list, and see if any freshly baked buffers.
+ * If head of queue is not baked, set timer.
+ */
+static struct sk_buff *netem_get_delayed(struct netem_sched_data *q)
+{
+ struct sk_buff *skb;
+ psched_time_t now;
+ long delay;
+
+ skb = skb_peek(&q->qdelay);
+ if (skb) {
+ const struct netem_skb_cb *cb
+ = (const struct netem_skb_cb *)skb->cb;
+
+ PSCHED_GET_TIME(now);
+ delay = PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now));
+ pr_debug("netem_dequeue: delay queue %p@%lu %ld\n",
+ skb, jiffies, delay);
+
+ /* it's baked enough */
+ if (delay <= 0) {
+ __skb_unlink(skb, &q->qdelay);
+ del_timer(&q->timer);
+ return skb;
+ }
+
+ if (!timer_pending(&q->timer)) {
+ q->timer.expires = jiffies + delay;
+ add_timer(&q->timer);
+ }
+ }
+ return NULL;
+}
+
+/* Dequeue packet.
+ * If packet needs to be held up, then put in the delay
+ * queue and set timer to wakeup later.
+ */
+static struct sk_buff *netem_dequeue(struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ struct sk_buff *skb;
+
+ skb = netem_get_delayed(q);
+ if (!skb && (skb = __skb_dequeue(&q->qnormal))) {
+ /* are we doing out of order packet skip? */
+ if (q->counter < q->gap) {
+ pr_debug("netem_dequeue: send %p normally\n", skb);
+ q->counter++;
+ } else {
+ /* don't send now hold for later */
+ pr_debug("netem_dequeue: hold [%p]@%lu\n", skb, jiffies);
+ __skb_queue_tail(&q->qdelay, skb);
+ q->counter = 0;
+ skb = netem_get_delayed(q);
+ }
+ }
+
+ if (skb)
+ sch->q.qlen--;
+ return skb;
+}
+
+static void netem_timer(unsigned long arg)
+{
+ struct Qdisc *sch = (struct Qdisc *)arg;
+
+ pr_debug("netem_timer: fired @%lu\n", jiffies);
+ netif_schedule(sch->dev);
+}
+
+static void netem_reset(struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+
+ skb_queue_purge(&q->qnormal);
+ skb_queue_purge(&q->qdelay);
+
+ sch->q.qlen = 0;
+ del_timer_sync(&q->timer);
+}
+
+static int netem_change(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ struct tc_netem_qopt *qopt = RTA_DATA(opt);
+
+ if (qopt->limit)
+ sch->dev->tx_queue_len = qopt->limit;
+
+ q->gap = qopt->gap;
+ q->loss = qopt->loss;
+ q->latency = qopt->latency;
+
+ return 0;
+}
+
+static int netem_init(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+
+ if (!opt)
+ return -EINVAL;
+
+ skb_queue_head_init(&q->qnormal);
+ skb_queue_head_init(&q->qdelay);
+ init_timer(&q->timer);
+ q->timer.function = netem_timer;
+ q->timer.data = (unsigned long) sch;
+ q->counter = 0;
+
+ return netem_change(sch, opt);
+}
+
+static void netem_destroy(struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+
+ del_timer_sync(&q->timer);
+}
+
+static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ unsigned char *b = skb->tail;
+ struct tc_netem_qopt qopt;
+
+ qopt.latency = q->latency;
+ qopt.limit = sch->dev->tx_queue_len;
+ qopt.loss = q->loss;
+ qopt.gap = q->gap;
+
+ 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 netem_qdisc_ops = {
+ .id = "netem",
+ .priv_size = sizeof(struct netem_sched_data),
+ .enqueue = netem_enqueue,
+ .dequeue = netem_dequeue,
+ .requeue = netem_requeue,
+ .init = netem_init,
+ .reset = netem_reset,
+ .destroy = netem_destroy,
+ .change = netem_change,
+ .dump = netem_dump,
+ .owner = THIS_MODULE,
+};
+
+
+static int __init netem_module_init(void)
+{
+ return register_qdisc(&netem_qdisc_ops);
+}
+static void __exit netem_module_exit(void)
+{
+ unregister_qdisc(&netem_qdisc_ops);
+}
+module_init(netem_module_init)
+module_exit(netem_module_exit)
+MODULE_LICENSE("GPL");
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