This includes the netem changes for 2.6 retargeted for 2.4
It covers:
* make duplication reinsert from root to fix qlen issues
* just use embedded qdisc for queueing to avoid qlen issues
* probabilistic reordering support
Index: netem-2.4/net/sched/sch_netem.c
===================================================================
--- netem-2.4.orig/net/sched/sch_netem.c
+++ netem-2.4/net/sched/sch_netem.c
@@ -56,7 +56,6 @@
struct netem_sched_data {
struct Qdisc *qdisc;
- struct sk_buff_head delayed;
struct timer_list timer;
u32 latency;
@@ -66,11 +65,12 @@ struct netem_sched_data {
u32 gap;
u32 jitter;
u32 duplicate;
+ u32 reorder;
struct crndstate {
unsigned long last;
unsigned long rho;
- } delay_cor, loss_cor, dup_cor;
+ } delay_cor, loss_cor, dup_cor, reorder_cor;
struct disttable {
u32 size;
@@ -140,81 +140,79 @@ static long tabledist(unsigned long mu,
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)
+/*
+ * Insert one skb into qdisc.
+ * Note: parent depends on return value to account for queue length.
+ * NET_XMIT_DROP: queue length didn't change.
+ * NET_XMIT_SUCCESS: one skb was queued.
+ */
+static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
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);
- sch->stats.bytes += skb->len;
- sch->stats.packets++;
-
- if (!timer_pending(&q->timer)) {
- q->timer.expires = jiffies + PSCHED_US2JIFFIE(td);
- add_timer(&q->timer);
- }
- return NET_XMIT_SUCCESS;
- }
-
- sch->stats.drops++;
- kfree_skb(skb);
- return NET_XMIT_DROP;
-}
+ struct sk_buff *skb2;
+ int ret;
+ int count = 1;
-static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
-{
- struct netem_sched_data *q = qdisc_priv(sch);
+ pr_debug("netem_enqueue skb=%p\n", skb);
- pr_debug("netem_enqueue skb=%p @%lu\n", skb, jiffies);
+ /* Random duplication */
+ if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
+ ++count;
/* Random packet drop 0 => none, ~0 => all */
- if (q->loss && q->loss >= get_crandom(&q->loss_cor)) {
- pr_debug("netem_enqueue: random loss\n");
+ if (q->loss && q->loss >= get_crandom(&q->loss_cor))
+ --count;
+
+ if (count == 0) {
sch->stats.drops++;
kfree_skb(skb);
- return 0; /* lie about loss so TCP doesn't know */
+ return NET_XMIT_DROP;
}
- /* Random duplication */
- if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) {
- struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
-
- pr_debug("netem_enqueue: dup %p\n", skb2);
- if (skb2)
- delay_skb(sch, skb2);
- }
-
- /* 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 we need to duplicate packet, then re-insert at top of the
+ * qdisc tree, since parent queuer expects that only one
+ * skb will be queued.
*/
- if (q->counter < q->gap) {
- int ret;
-
+ if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
+ struct Qdisc *rootq = sch->dev->qdisc;
+ u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
+ q->duplicate = 0;
+
+ rootq->enqueue(skb2, rootq);
+ q->duplicate = dupsave;
+ }
+
+ if (q->gap == 0 /* not doing reordering */
+ || q->counter < q->gap /* inside last reordering gap */
+ || q->reorder < get_crandom(&q->reorder_cor)) {
+ psched_time_t now;
+ PSCHED_GET_TIME(now);
+ PSCHED_TADD2(now, tabledist(q->latency, q->jitter,
+ &q->delay_cor, q->delay_dist),
+ cb->time_to_send);
++q->counter;
ret = q->qdisc->enqueue(skb, q->qdisc);
- if (likely(ret == NET_XMIT_SUCCESS)) {
- sch->q.qlen++;
- sch->stats.bytes += skb->len;
- sch->stats.packets++;
- } else
- sch->stats.drops++;
- return ret;
+ } else {
+ /*
+ * Do re-ordering by putting one out of N packets at the front
+ * of the queue.
+ */
+ PSCHED_GET_TIME(cb->time_to_send);
+ q->counter = 0;
+ ret = q->qdisc->ops->requeue(skb, q->qdisc);
}
-
- q->counter = 0;
- return delay_skb(sch, skb);
+ if (likely(ret == NET_XMIT_SUCCESS)) {
+ sch->q.qlen++;
+ sch->stats.bytes += skb->len;
+ sch->stats.packets++;
+ } else
+ sch->stats.drops++;
+
+ pr_debug("netem: enqueue ret %d\n", ret);
+ return ret;
}
/* Requeue packets but don't change time stamp */
@@ -241,56 +239,46 @@ static unsigned int netem_drop(struct Qd
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) {
+ if (skb) {
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);
+ psched_time_t now;
+ long delay;
/* if more time remaining? */
- if (delay > 0) {
- mod_timer(&q->timer, jiffies + delay);
- break;
+ PSCHED_GET_TIME(now);
+ delay = PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now));
+ pr_debug("netem_run: skb=%p delay=%ld\n", skb, delay);
+ if (delay <= 0) {
+ pr_debug("netem_dequeue: return skb=%p\n", skb);
+ sch->q.qlen--;
+ sch->flags &= ~TCQ_F_THROTTLED;
+ return skb;
}
- __skb_unlink(skb, &q->delayed);
- if (q->qdisc->enqueue(skb, q->qdisc))
+ mod_timer(&q->timer, jiffies + delay);
+ sch->flags |= TCQ_F_THROTTLED;
+
+ if (q->qdisc->ops->requeue(skb, q->qdisc) != 0)
sch->stats.drops++;
- else
- sch->q.qlen++;
}
- qdisc_run(dev);
- spin_unlock_bh(&dev->queue_lock);
+
+ return NULL;
+}
+
+static void netem_watchdog(unsigned long arg)
+{
+ struct Qdisc *sch = (struct Qdisc *)arg;
+
+ pr_debug("netem_watchdog qlen=%d\n", sch->q.qlen);
+ sch->flags &= ~TCQ_F_THROTTLED;
+ netif_schedule(sch->dev);
}
static void netem_reset(struct Qdisc *sch)
@@ -298,9 +286,8 @@ static void netem_reset(struct Qdisc *sc
struct netem_sched_data *q = qdisc_priv(sch);
qdisc_reset(q->qdisc);
- skb_queue_purge(&q->delayed);
-
sch->q.qlen = 0;
+ sch->flags &= ~TCQ_F_THROTTLED;
del_timer_sync(&q->timer);
}
@@ -366,6 +353,19 @@ static int get_correlation(struct Qdisc
return 0;
}
+static int get_reorder(struct Qdisc *sch, const struct rtattr *attr)
+{
+ struct netem_sched_data *q = qdisc_priv(sch);
+ const struct tc_netem_reorder *r = RTA_DATA(attr);
+
+ if (RTA_PAYLOAD(attr) != sizeof(*r))
+ return -EINVAL;
+
+ q->reorder = r->probability;
+ init_crandom(&q->reorder_cor, r->correlation);
+ return 0;
+}
+
static int netem_change(struct Qdisc *sch, struct rtattr *opt)
{
struct netem_sched_data *q = qdisc_priv(sch);
@@ -386,9 +386,15 @@ static int netem_change(struct Qdisc *sc
q->jitter = qopt->jitter;
q->limit = qopt->limit;
q->gap = qopt->gap;
+ q->counter = 0;
q->loss = qopt->loss;
q->duplicate = qopt->duplicate;
+ /* for compatiablity with earlier versions.
+ * if gap is set, need to assume 100% probablity
+ */
+ q->reorder = ~0;
+
/* Handle nested options after initial queue options.
* Should have put all options in nested format but too late now.
*/
@@ -410,6 +416,11 @@ static int netem_change(struct Qdisc *sc
if (ret)
return ret;
}
+ if (tb[TCA_NETEM_REORDER-1]) {
+ ret = get_reorder(sch, tb[TCA_NETEM_REORDER-1]);
+ if (ret)
+ return ret;
+ }
}
@@ -425,11 +436,9 @@ static int netem_init(struct Qdisc *sch,
return -EINVAL;
MOD_INC_USE_COUNT;
- 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) {
@@ -463,6 +472,7 @@ static int netem_dump(struct Qdisc *sch,
struct rtattr *rta = (struct rtattr *) b;
struct tc_netem_qopt qopt;
struct tc_netem_corr cor;
+ struct tc_netem_reorder reorder;
qopt.latency = q->latency;
qopt.jitter = q->jitter;
@@ -476,6 +486,11 @@ static int netem_dump(struct Qdisc *sch,
cor.loss_corr = q->loss_cor.rho;
cor.dup_corr = q->dup_cor.rho;
RTA_PUT(skb, TCA_NETEM_CORR, sizeof(cor), &cor);
+
+ reorder.probability = q->reorder;
+ reorder.correlation = q->reorder_cor.rho;
+ RTA_PUT(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder);
+
rta->rta_len = skb->tail - b;
return skb->len;
Index: netem-2.4/include/linux/pkt_sched.h
===================================================================
--- netem-2.4.orig/include/linux/pkt_sched.h
+++ netem-2.4/include/linux/pkt_sched.h
@@ -439,16 +439,17 @@ enum
TCA_NETEM_UNSPEC,
TCA_NETEM_CORR,
TCA_NETEM_DELAY_DIST,
+ TCA_NETEM_REORDER,
};
-#define TCA_NETEM_MAX TCA_NETEM_DELAY_DIST
+#define TCA_NETEM_MAX TCA_NETEM_REORDER
struct tc_netem_qopt
{
__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 gap; /* re-ordering gap (0 for none) */
__u32 duplicate; /* random packet dup (0=none ~0=100%) */
__u32 jitter; /* random jitter in latency (us) */
};
@@ -460,6 +461,12 @@ struct tc_netem_corr
__u32 dup_corr; /* duplicate correlation */
};
+struct tc_netem_reorder
+{
+ __u32 probability;
+ __u32 correlation;
+};
+
#define NETEM_DIST_SCALE 8192
#endif
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