From c865e5d99e25a171e8262fc0f7ba608568633c64 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Wed, 21 Dec 2005 19:03:44 -0800 Subject: [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: Stephen Hemminger Signed-off-by: David S. Miller --- net/sched/sch_netem.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 46 insertions(+), 3 deletions(-) (limited to 'net/sched') diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 82fb07aa06a5..ba5283204837 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -25,7 +25,7 @@ #include -#define VERSION "1.1" +#define VERSION "1.2" /* Network Emulation Queuing algorithm. ==================================== @@ -65,11 +65,12 @@ struct netem_sched_data { u32 jitter; u32 duplicate; u32 reorder; + u32 corrupt; struct crndstate { unsigned long last; unsigned long rho; - } delay_cor, loss_cor, dup_cor, reorder_cor; + } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor; struct disttable { u32 size; @@ -183,6 +184,23 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) 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 */ || q->counter < q->gap /* inside last reordering gap */ || q->reorder < get_crandom(&q->reorder_cor)) { @@ -382,6 +400,20 @@ static int get_reorder(struct Qdisc *sch, const struct rtattr *attr) 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) { struct netem_sched_data *q = qdisc_priv(sch); @@ -432,13 +464,19 @@ static int netem_change(struct Qdisc *sch, struct rtattr *opt) if (ret) return ret; } + if (tb[TCA_NETEM_REORDER-1]) { ret = get_reorder(sch, tb[TCA_NETEM_REORDER-1]); if (ret) return ret; } - } + if (tb[TCA_NETEM_CORRUPT-1]) { + ret = get_corrupt(sch, tb[TCA_NETEM_CORRUPT-1]); + if (ret) + return ret; + } + } 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_corr cor; struct tc_netem_reorder reorder; + struct tc_netem_corrupt corrupt; qopt.latency = q->latency; 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; 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; return skb->len; -- cgit v1.2.1