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authorStephen Hemminger <shemminger@osdl.org>2005-05-26 15:53:49 -0400
committerDavid S. Miller <davem@davemloft.net>2005-05-26 15:53:49 -0400
commit0afb51e72855971dba83b3c6b70c547c2d1161fd (patch)
tree8f0e3cd40e381f4dd9de2e7431490ae8cbbf6498 /net
parentcdbbde14cb55dd10771ce79154f787322d88411b (diff)
[PKT_SCHED]: netem: reinsert for duplication
Handle duplication of packets in netem by re-inserting at top of qdisc tree. This avoid problems with qlen accounting with nested qdisc. This recursion requires no additional locking but will potentially increase stack depth. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/sch_netem.c53
1 files changed, 29 insertions, 24 deletions
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index e0c9fbe73b15..5c0f0c209a4c 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -203,42 +203,47 @@ static int netem_run(struct Qdisc *sch)
203 return 0; 203 return 0;
204} 204}
205 205
206/*
207 * Insert one skb into qdisc.
208 * Note: parent depends on return value to account for queue length.
209 * NET_XMIT_DROP: queue length didn't change.
210 * NET_XMIT_SUCCESS: one skb was queued.
211 */
206static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) 212static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
207{ 213{
208 struct netem_sched_data *q = qdisc_priv(sch); 214 struct netem_sched_data *q = qdisc_priv(sch);
215 struct sk_buff *skb2;
209 int ret; 216 int ret;
217 int count = 1;
210 218
211 pr_debug("netem_enqueue skb=%p\n", skb); 219 pr_debug("netem_enqueue skb=%p\n", skb);
212 220
221 /* Random duplication */
222 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
223 ++count;
224
213 /* Random packet drop 0 => none, ~0 => all */ 225 /* Random packet drop 0 => none, ~0 => all */
214 if (q->loss && q->loss >= get_crandom(&q->loss_cor)) { 226 if (q->loss && q->loss >= get_crandom(&q->loss_cor))
215 pr_debug("netem_enqueue: random loss\n"); 227 --count;
228
229 if (count == 0) {
216 sch->qstats.drops++; 230 sch->qstats.drops++;
217 kfree_skb(skb); 231 kfree_skb(skb);
218 return 0; /* lie about loss so TCP doesn't know */ 232 return NET_XMIT_DROP;
219 } 233 }
220 234
221 /* Random duplication */ 235 /*
222 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) { 236 * If we need to duplicate packet, then re-insert at top of the
223 struct sk_buff *skb2; 237 * qdisc tree, since parent queuer expects that only one
224 238 * skb will be queued.
225 skb2 = skb_clone(skb, GFP_ATOMIC); 239 */
226 if (skb2 && netem_delay(sch, skb2) == NET_XMIT_SUCCESS) { 240 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
227 struct Qdisc *qp; 241 struct Qdisc *rootq = sch->dev->qdisc;
228 242 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
229 /* Since one packet can generate two packets in the 243 q->duplicate = 0;
230 * queue, the parent's qlen accounting gets confused, 244
231 * so fix it. 245 rootq->enqueue(skb2, rootq);
232 */ 246 q->duplicate = dupsave;
233 qp = qdisc_lookup(sch->dev, TC_H_MAJ(sch->parent));
234 if (qp)
235 qp->q.qlen++;
236
237 sch->q.qlen++;
238 sch->bstats.bytes += skb2->len;
239 sch->bstats.packets++;
240 } else
241 sch->qstats.drops++;
242 } 247 }
243 248
244 /* If doing simple delay then gap == 0 so all packets 249 /* If doing simple delay then gap == 0 so all packets