Beispiel #1
0
/*
 * 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);
	/* We don't fill cb now as skb_unshare() may invalidate it */
	struct netem_skb_cb *cb;
	struct sk_buff *skb2;
	int count = 1;

	/* Random duplication */
	if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
		++count;

	/* Drop packet? */
	if (loss_event(q))
		--count;

	if (count == 0) {
		sch->qstats.drops++;
		kfree_skb(skb);
		return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
	}

	skb_orphan(skb);

	/*
	 * 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 (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
		struct Qdisc *rootq = qdisc_root(sch);
		u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
		q->duplicate = 0;

		qdisc_enqueue_root(skb2, rootq);
		q->duplicate = dupsave;
	}

	/*
	 * Randomized packet corruption.
	 * Make copy if needed since we are modifying
	 * If packet is going to be hardware checksummed, then
	 * do it now in software before we mangle it.
	 */
	if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
		if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
		    (skb->ip_summed == CHECKSUM_PARTIAL &&
		     skb_checksum_help(skb)))
			return qdisc_drop(skb, sch);

		skb->data[net_random() % skb_headlen(skb)] ^= 1<<(net_random() % 8);
	}

	if (unlikely(skb_queue_len(&sch->q) >= sch->limit))
		return qdisc_reshape_fail(skb, sch);

	sch->qstats.backlog += qdisc_pkt_len(skb);

	cb = netem_skb_cb(skb);
	if (q->gap == 0 ||		/* not doing reordering */
	    q->counter < q->gap - 1 ||	/* inside last reordering gap */
	    q->reorder < get_crandom(&q->reorder_cor)) {
		psched_time_t now;
		psched_tdiff_t delay;

		delay = tabledist(q->latency, q->jitter,
				  &q->delay_cor, q->delay_dist);

		now = psched_get_time();

		if (q->rate) {
			struct sk_buff_head *list = &sch->q;

			delay += packet_len_2_sched_time(skb->len, q);

			if (!skb_queue_empty(list)) {
				/*
				 * Last packet in queue is reference point (now).
				 * First packet in queue is already in flight,
				 * calculate this time bonus and substract
				 * from delay.
				 */
				delay -= now - netem_skb_cb(skb_peek(list))->time_to_send;
				now = netem_skb_cb(skb_peek_tail(list))->time_to_send;
			}
		}

		cb->time_to_send = now + delay;
		++q->counter;
		tfifo_enqueue(skb, sch);
	} else {
		/*
		 * Do re-ordering by putting one out of N packets at the front
		 * of the queue.
		 */
		cb->time_to_send = psched_get_time();
		q->counter = 0;

		__skb_queue_head(&sch->q, skb);
		sch->qstats.requeues++;
	}

	return NET_XMIT_SUCCESS;
}
Beispiel #2
0
/*
 * 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);
	/* We don't fill cb now as skb_unshare() may invalidate it */
	struct netem_skb_cb *cb;
	struct sk_buff *skb2;
	int ret;
	int count = 1;

	/* Random duplication */
	if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
		++count;

	/* Drop packet? */
	if (loss_event(q))
		--count;

	if (count == 0) {
		sch->qstats.drops++;
		kfree_skb(skb);
		return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
	}

	skb_orphan(skb);

	/*
	 * 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 (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
		struct Qdisc *rootq = qdisc_root(sch);
		u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
		q->duplicate = 0;

		qdisc_enqueue_root(skb2, rootq);
		q->duplicate = dupsave;
	}

	/*
	 * Randomized packet corruption.
	 * Make copy if needed since we are modifying
	 * If packet is going to be hardware checksummed, then
	 * do it now in software before we mangle it.
	 */
	if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
		if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
		    (skb->ip_summed == CHECKSUM_PARTIAL &&
		     skb_checksum_help(skb))) {
			sch->qstats.drops++;
			return NET_XMIT_DROP;
		}

		skb->data[net_random() % skb_headlen(skb)] ^= 1<<(net_random() % 8);
	}

	cb = netem_skb_cb(skb);
	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_tdiff_t delay;

		delay = tabledist(q->latency, q->jitter,
				  &q->delay_cor, q->delay_dist);

		now = psched_get_time();
		cb->time_to_send = now + delay;
		++q->counter;
		ret = qdisc_enqueue(skb, q->qdisc);
	} else {
		/*
		 * Do re-ordering by putting one out of N packets at the front
		 * of the queue.
		 */
		cb->time_to_send = psched_get_time();
		q->counter = 0;

		__skb_queue_head(&q->qdisc->q, skb);
		sch->qstats.backlog += qdisc_pkt_len(skb);
		sch->qstats.requeues++;
		ret = NET_XMIT_SUCCESS;
	}

	if (ret != NET_XMIT_SUCCESS) {
		if (net_xmit_drop_count(ret)) {
			sch->qstats.drops++;
			return ret;
		}
	}

	sch->q.qlen++;
	return NET_XMIT_SUCCESS;
}