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Commit c865e5d9 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

[PKT_SCHED] netem: packet corruption option 



Here is a new feature for netem in 2.6.16. It adds the ability to
randomly corrupt packets with netem. A version was done by
Hagen Paul Pfeifer, but I redid it to handle the cases of backwards
compatibility with netlink interface and presence of hardware checksum
offload. It is useful for testing hardware offload in devices.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8cbb512e

include/linux/pkt_sched.h

+7 −0
Original line number Original line Diff line number Diff line
@@ -429,6 +429,7 @@ enum 
	TCA_NETEM_CORR,

	TCA_NETEM_CORR,

	TCA_NETEM_DELAY_DIST,

	TCA_NETEM_DELAY_DIST,

	TCA_NETEM_REORDER,

	TCA_NETEM_REORDER,

	TCA_NETEM_CORRUPT,

	__TCA_NETEM_MAX,

	__TCA_NETEM_MAX,

};

};
@@ -457,6 +458,12 @@ struct tc_netem_reorder 
	__u32	correlation;

	__u32	correlation;

};

};





struct tc_netem_corrupt

{

	__u32	probability;

	__u32	correlation;

};



#define NETEM_DIST_SCALE	8192

#define NETEM_DIST_SCALE	8192





#endif
 
#endif

net/sched/sch_netem.c

+46 −3
Original line number Original line Diff line number Diff line
@@ -25,7 +25,7 @@ 




#include <net/pkt_sched.h>

#include <net/pkt_sched.h>





#define VERSION "1.1"

#define VERSION "1.2"





/*	Network Emulation Queuing algorithm.

/*	Network Emulation Queuing algorithm.

	====================================

	====================================
@@ -65,11 +65,12 @@ struct netem_sched_data { 
	u32 jitter;

	u32 jitter;

	u32 duplicate;

	u32 duplicate;

	u32 reorder;

	u32 reorder;

	u32 corrupt;





	struct crndstate {

	struct crndstate {

		unsigned long last;

		unsigned long last;

		unsigned long rho;

		unsigned long rho;

	} delay_cor, loss_cor, dup_cor, reorder_cor;

	} delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;





	struct disttable {

	struct disttable {

		u32  size;

		u32  size;
@@ -183,6 +184,23 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) 
		q->duplicate = dupsave;

		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_HW

			&& skb_checksum_help(skb, 0))) {

			sch->qstats.drops++;

			return NET_XMIT_DROP;

		}



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

	}



	if (q->gap == 0 		/* not doing reordering */

	if (q->gap == 0 		/* not doing reordering */

	    || q->counter < q->gap 	/* inside last reordering gap */

	    || q->counter < q->gap 	/* inside last reordering gap */

	    || q->reorder < get_crandom(&q->reorder_cor)) {

	    || q->reorder < get_crandom(&q->reorder_cor)) {
@@ -382,6 +400,20 @@ static int get_reorder(struct Qdisc *sch, const struct rtattr *attr) 
	return 0;

	return 0;

}

}





static int get_corrupt(struct Qdisc *sch, const struct rtattr *attr)

{

	struct netem_sched_data *q = qdisc_priv(sch);

	const struct tc_netem_corrupt *r = RTA_DATA(attr);



	if (RTA_PAYLOAD(attr) != sizeof(*r))

		return -EINVAL;



	q->corrupt = r->probability;

	init_crandom(&q->corrupt_cor, r->correlation);

	return 0;

}



/* Parse netlink message to set options */

static int netem_change(struct Qdisc *sch, struct rtattr *opt)

static int netem_change(struct Qdisc *sch, struct rtattr *opt)

{

{

	struct netem_sched_data *q = qdisc_priv(sch);

	struct netem_sched_data *q = qdisc_priv(sch);
@@ -432,13 +464,19 @@ static int netem_change(struct Qdisc *sch, struct rtattr *opt) 
			if (ret)

			if (ret)

				return ret;

				return ret;

		}

		}



		if (tb[TCA_NETEM_REORDER-1]) {

		if (tb[TCA_NETEM_REORDER-1]) {

			ret = get_reorder(sch, tb[TCA_NETEM_REORDER-1]);

			ret = get_reorder(sch, tb[TCA_NETEM_REORDER-1]);

			if (ret)

			if (ret)

				return ret;

				return ret;

		}

		}

	}





		if (tb[TCA_NETEM_CORRUPT-1]) {

			ret = get_corrupt(sch, tb[TCA_NETEM_CORRUPT-1]);

			if (ret)

				return ret;

		}

	}





	return 0;

	return 0;

}

}
@@ -564,6 +602,7 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 
	struct tc_netem_qopt qopt;

	struct tc_netem_qopt qopt;

	struct tc_netem_corr cor;

	struct tc_netem_corr cor;

	struct tc_netem_reorder reorder;

	struct tc_netem_reorder reorder;

	struct tc_netem_corrupt corrupt;





	qopt.latency = q->latency;

	qopt.latency = q->latency;

	qopt.jitter = q->jitter;

	qopt.jitter = q->jitter;
@@ -582,6 +621,10 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 
	reorder.correlation = q->reorder_cor.rho;

	reorder.correlation = q->reorder_cor.rho;

	RTA_PUT(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder);

	RTA_PUT(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder);





	corrupt.probability = q->corrupt;

	corrupt.correlation = q->corrupt_cor.rho;

	RTA_PUT(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt);



	rta->rta_len = skb->tail - b;

	rta->rta_len = skb->tail - b;





	return skb->len;

	return skb->len;