Linux-2.6.12-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!
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");
