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!

1 files changed, 598 insertions, 0 deletions

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
new file mode 100644
index 0000000..31c29de
--- /dev/null
+++ b/net/sched/sch_netem.c
@@ -0,0 +1,598 @@
+/*
+ * 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.
+ *
+ *  		Many of the algorithms and ideas for this came from
+ *		NIST Net which is not copyrighted. 
+ *
+ * Authors:	Stephen Hemminger <shemminger@osdl.org>
+ *		Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+
+#include <net/pkt_sched.h>
+
+/*	Network Emulation Queuing algorithm.
+	====================================
+
+	Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
+		 Network Emulation Tool
+		 [2] Luigi Rizzo, DummyNet for FreeBSD
+
+	 ----------------------------------------------------------------
+
+	 This started out as a simple way to delay outgoing packets to
+	 test TCP but has grown to include most of the functionality
+	 of a full blown network emulator like NISTnet. It can delay
+	 packets and add random jitter (and correlation). The random
+	 distribution can be loaded from a table as well to provide
+	 normal, Pareto, or experimental curves. Packet loss,
+	 duplication, and reordering can also be emulated.
+
+	 This qdisc does not do classification that can be handled in
+	 layering other disciplines.  It does not need to do bandwidth
+	 control either since that can be handled by using token
+	 bucket or other rate control.
+
+	 The simulator is limited by the Linux timer resolution
+	 and will create packet bursts on the HZ boundary (1ms).
+*/
+
+struct netem_sched_data {
+	struct Qdisc	*qdisc;
+	struct sk_buff_head delayed;
+	struct timer_list timer;
+
+	u32 latency;
+	u32 loss;
+	u32 limit;
+	u32 counter;
+	u32 gap;
+	u32 jitter;
+	u32 duplicate;
+
+	struct crndstate {
+		unsigned long last;
+		unsigned long rho;
+	} delay_cor, loss_cor, dup_cor;
+
+	struct disttable {
+		u32  size;
+		s16 table[0];
+	} *delay_dist;
+};
+
+/* Time stamp put into socket buffer control block */
+struct netem_skb_cb {
+	psched_time_t	time_to_send;
+};
+
+/* init_crandom - initialize correlated random number generator
+ * Use entropy source for initial seed.
+ */
+static void init_crandom(struct crndstate *state, unsigned long rho)
+{
+	state->rho = rho;
+	state->last = net_random();
+}
+
+/* get_crandom - correlated random number generator
+ * Next number depends on last value.
+ * rho is scaled to avoid floating point.
+ */
+static unsigned long get_crandom(struct crndstate *state)
+{
+	u64 value, rho;
+	unsigned long answer;
+
+	if (state->rho == 0)	/* no correllation */
+		return net_random();
+
+	value = net_random();
+	rho = (u64)state->rho + 1;
+	answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
+	state->last = answer;
+	return answer;
+}
+
+/* tabledist - return a pseudo-randomly distributed value with mean mu and
+ * std deviation sigma.  Uses table lookup to approximate the desired
+ * distribution, and a uniformly-distributed pseudo-random source.
+ */
+static long tabledist(unsigned long mu, long sigma, 
+		      struct crndstate *state, const struct disttable *dist)
+{
+	long t, x;
+	unsigned long rnd;
+
+	if (sigma == 0)
+		return mu;
+
+	rnd = get_crandom(state);
+
+	/* default uniform distribution */
+	if (dist == NULL) 
+		return (rnd % (2*sigma)) - sigma + mu;
+
+	t = dist->table[rnd % dist->size];
+	x = (sigma % NETEM_DIST_SCALE) * t;
+	if (x >= 0)
+		x += NETEM_DIST_SCALE/2;
+	else
+		x -= NETEM_DIST_SCALE/2;
+
+	return  x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
+}
+
+/* Put skb in the private delayed queue. */
+static int delay_skb(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb;
+	psched_tdiff_t td;
+	psched_time_t now;
+	
+	PSCHED_GET_TIME(now);
+	td = tabledist(q->latency, q->jitter, &q->delay_cor, q->delay_dist);
+	PSCHED_TADD2(now, td, cb->time_to_send);
+	
+	/* Always queue at tail to keep packets in order */
+	if (likely(q->delayed.qlen < q->limit)) {
+		__skb_queue_tail(&q->delayed, skb);
+		if (!timer_pending(&q->timer)) {
+			q->timer.expires = jiffies + PSCHED_US2JIFFIE(td);
+			add_timer(&q->timer);
+		}
+		return NET_XMIT_SUCCESS;
+	}
+
+	kfree_skb(skb);
+	return NET_XMIT_DROP;
+}
+
+static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb2;
+	int ret;
+
+	pr_debug("netem_enqueue skb=%p @%lu\n", skb, jiffies);
+
+	/* Random packet drop 0 => none, ~0 => all */
+	if (q->loss && q->loss >= get_crandom(&q->loss_cor)) {
+		pr_debug("netem_enqueue: random loss\n");
+		sch->qstats.drops++;
+		kfree_skb(skb);
+		return 0;	/* lie about loss so TCP doesn't know */
+	}
+
+	/* Random duplication */
+	if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)
+	    && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
+		pr_debug("netem_enqueue: dup %p\n", skb2);
+
+		if (delay_skb(sch, skb2)) {
+			sch->q.qlen++;
+			sch->bstats.bytes += skb2->len;
+			sch->bstats.packets++;
+		} else
+			sch->qstats.drops++;
+	}
+
+	/* If doing simple delay then gap == 0 so all packets
+	 * go into the delayed holding queue
+	 * otherwise if doing out of order only "1 out of gap"
+	 * packets will be delayed.
+	 */
+	if (q->counter < q->gap) {
+		++q->counter;
+		ret = q->qdisc->enqueue(skb, q->qdisc);
+	} else {
+		q->counter = 0;
+		ret = delay_skb(sch, skb);
+	}
+
+	if (likely(ret == NET_XMIT_SUCCESS)) {
+		sch->q.qlen++;
+		sch->bstats.bytes += skb->len;
+		sch->bstats.packets++;
+	} else
+		sch->qstats.drops++;
+
+	return ret;
+}
+
+/* Requeue packets but don't change time stamp */
+static int netem_requeue(struct sk_buff *skb, struct Qdisc *sch)
+{
+	struct netem_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 netem_drop(struct Qdisc* sch)
+{
+	struct netem_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;
+}
+
+/* Dequeue packet.
+ *  Move all packets that are ready to send from the delay holding
+ *  list to the underlying qdisc, then just call dequeue
+ */
+static struct sk_buff *netem_dequeue(struct Qdisc *sch)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb;
+
+	skb = q->qdisc->dequeue(q->qdisc);
+	if (skb) 
+		sch->q.qlen--;
+	return skb;
+}
+
+static void netem_watchdog(unsigned long arg)
+{
+	struct Qdisc *sch = (struct Qdisc *)arg;
+	struct netem_sched_data *q = qdisc_priv(sch);
+	struct net_device *dev = sch->dev;
+	struct sk_buff *skb;
+	psched_time_t now;
+
+	pr_debug("netem_watchdog: fired @%lu\n", jiffies);
+
+	spin_lock_bh(&dev->queue_lock);
+	PSCHED_GET_TIME(now);
+
+	while ((skb = skb_peek(&q->delayed)) != NULL) {
+		const struct netem_skb_cb *cb
+			= (const struct netem_skb_cb *)skb->cb;
+		long delay 
+			= PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now));
+		pr_debug("netem_watchdog: skb %p@%lu %ld\n",
+			 skb, jiffies, delay);
+
+		/* if more time remaining? */
+		if (delay > 0) {
+			mod_timer(&q->timer, jiffies + delay);
+			break;
+		}
+		__skb_unlink(skb, &q->delayed);
+
+		if (q->qdisc->enqueue(skb, q->qdisc)) {
+			sch->q.qlen--;
+			sch->qstats.drops++;
+		}
+	}
+	qdisc_run(dev);
+	spin_unlock_bh(&dev->queue_lock);
+}
+
+static void netem_reset(struct Qdisc *sch)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+
+	qdisc_reset(q->qdisc);
+	skb_queue_purge(&q->delayed);
+
+	sch->q.qlen = 0;
+	del_timer_sync(&q->timer);
+}
+
+static int set_fifo_limit(struct Qdisc *q, int limit)
+{
+        struct rtattr *rta;
+	int ret = -ENOMEM;
+
+	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);
+	}
+	return ret;
+}
+
+/*
+ * Distribution data is a variable size payload containing
+ * signed 16 bit values.
+ */
+static int get_dist_table(struct Qdisc *sch, const struct rtattr *attr)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	unsigned long n = RTA_PAYLOAD(attr)/sizeof(__s16);
+	const __s16 *data = RTA_DATA(attr);
+	struct disttable *d;
+	int i;
+
+	if (n > 65536)
+		return -EINVAL;
+
+	d = kmalloc(sizeof(*d) + n*sizeof(d->table[0]), GFP_KERNEL);
+	if (!d)
+		return -ENOMEM;
+
+	d->size = n;
+	for (i = 0; i < n; i++)
+		d->table[i] = data[i];
+	
+	spin_lock_bh(&sch->dev->queue_lock);
+	d = xchg(&q->delay_dist, d);
+	spin_unlock_bh(&sch->dev->queue_lock);
+
+	kfree(d);
+	return 0;
+}
+
+static int get_correlation(struct Qdisc *sch, const struct rtattr *attr)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	const struct tc_netem_corr *c = RTA_DATA(attr);
+
+	if (RTA_PAYLOAD(attr) != sizeof(*c))
+		return -EINVAL;
+
+	init_crandom(&q->delay_cor, c->delay_corr);
+	init_crandom(&q->loss_cor, c->loss_corr);
+	init_crandom(&q->dup_cor, c->dup_corr);
+	return 0;
+}
+
+static int netem_change(struct Qdisc *sch, struct rtattr *opt)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	struct tc_netem_qopt *qopt;
+	int ret;
+	
+	if (opt == NULL || RTA_PAYLOAD(opt) < sizeof(*qopt))
+		return -EINVAL;
+
+	qopt = RTA_DATA(opt);
+	ret = set_fifo_limit(q->qdisc, qopt->limit);
+	if (ret) {
+		pr_debug("netem: can't set fifo limit\n");
+		return ret;
+	}
+	
+	q->latency = qopt->latency;
+	q->jitter = qopt->jitter;
+	q->limit = qopt->limit;
+	q->gap = qopt->gap;
+	q->loss = qopt->loss;
+	q->duplicate = qopt->duplicate;
+
+	/* Handle nested options after initial queue options.
+	 * Should have put all options in nested format but too late now.
+	 */ 
+	if (RTA_PAYLOAD(opt) > sizeof(*qopt)) {
+		struct rtattr *tb[TCA_NETEM_MAX];
+		if (rtattr_parse(tb, TCA_NETEM_MAX, 
+				 RTA_DATA(opt) + sizeof(*qopt),
+				 RTA_PAYLOAD(opt) - sizeof(*qopt)))
+			return -EINVAL;
+
+		if (tb[TCA_NETEM_CORR-1]) {
+			ret = get_correlation(sch, tb[TCA_NETEM_CORR-1]);
+			if (ret)
+				return ret;
+		}
+
+		if (tb[TCA_NETEM_DELAY_DIST-1]) {
+			ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST-1]);
+			if (ret)
+				return ret;
+		}
+	}
+
+
+	return 0;
+}
+
+static int netem_init(struct Qdisc *sch, struct rtattr *opt)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	int ret;
+
+	if (!opt)
+		return -EINVAL;
+
+	skb_queue_head_init(&q->delayed);
+	init_timer(&q->timer);
+	q->timer.function = netem_watchdog;
+	q->timer.data = (unsigned long) sch;
+	q->counter = 0;
+
+	q->qdisc = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops);
+	if (!q->qdisc) {
+		pr_debug("netem: qdisc create failed\n");
+		return -ENOMEM;
+	}
+
+	ret = netem_change(sch, opt);
+	if (ret) {
+		pr_debug("netem: change failed\n");
+		qdisc_destroy(q->qdisc);
+	}
+	return ret;
+}
+
+static void netem_destroy(struct Qdisc *sch)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+
+	del_timer_sync(&q->timer);
+	qdisc_destroy(q->qdisc);
+	kfree(q->delay_dist);
+}
+
+static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	const struct netem_sched_data *q = qdisc_priv(sch);
+	unsigned char	 *b = skb->tail;
+	struct rtattr *rta = (struct rtattr *) b;
+	struct tc_netem_qopt qopt;
+	struct tc_netem_corr cor;
+
+	qopt.latency = q->latency;
+	qopt.jitter = q->jitter;
+	qopt.limit = q->limit;
+	qopt.loss = q->loss;
+	qopt.gap = q->gap;
+	qopt.duplicate = q->duplicate;
+	RTA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
+
+	cor.delay_corr = q->delay_cor.rho;
+	cor.loss_corr = q->loss_cor.rho;
+	cor.dup_corr = q->dup_cor.rho;
+	RTA_PUT(skb, TCA_NETEM_CORR, sizeof(cor), &cor);
+	rta->rta_len = skb->tail - b;
+
+	return skb->len;
+
+rtattr_failure:
+	skb_trim(skb, b - skb->data);
+	return -1;
+}
+
+static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
+			  struct sk_buff *skb, struct tcmsg *tcm)
+{
+	struct netem_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 netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
+		     struct Qdisc **old)
+{
+	struct netem_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 *netem_leaf(struct Qdisc *sch, unsigned long arg)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	return q->qdisc;
+}
+
+static unsigned long netem_get(struct Qdisc *sch, u32 classid)
+{
+	return 1;
+}
+
+static void netem_put(struct Qdisc *sch, unsigned long arg)
+{
+}
+
+static int netem_change_class(struct Qdisc *sch, u32 classid, u32 parentid, 
+			    struct rtattr **tca, unsigned long *arg)
+{
+	return -ENOSYS;
+}
+
+static int netem_delete(struct Qdisc *sch, unsigned long arg)
+{
+	return -ENOSYS;
+}
+
+static void netem_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 **netem_find_tcf(struct Qdisc *sch, unsigned long cl)
+{
+	return NULL;
+}
+
+static struct Qdisc_class_ops netem_class_ops = {
+	.graft		=	netem_graft,
+	.leaf		=	netem_leaf,
+	.get		=	netem_get,
+	.put		=	netem_put,
+	.change		=	netem_change_class,
+	.delete		=	netem_delete,
+	.walk		=	netem_walk,
+	.tcf_chain	=	netem_find_tcf,
+	.dump		=	netem_dump_class,
+};
+
+static struct Qdisc_ops netem_qdisc_ops = {
+	.id		=	"netem",
+	.cl_ops		=	&netem_class_ops,
+	.priv_size	=	sizeof(struct netem_sched_data),
+	.enqueue	=	netem_enqueue,
+	.dequeue	=	netem_dequeue,
+	.requeue	=	netem_requeue,
+	.drop		=	netem_drop,
+	.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");