[PATCH 2.6] (3/4) netem - support packet duplication

[Stephen Hemminger <shemminger@xxxxxxxx>]

Add support for duplicating packets.

Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxx>

diff -Nru a/net/sched/sch_netem.c b/net/sched/sch_netem.c
--- a/net/sched/sch_netem.c     2004-08-24 16:58:13 -07:00
+++ b/net/sched/sch_netem.c     2004-08-24 16:58:13 -07:00
@@ -62,6 +62,7 @@
        u32 counter;
        u32 gap;
        u32 jitter;
+       u32 duplicate;
 };
 
 /* Time stamp put into socket buffer control block */
@@ -624,22 +625,13 @@
 /* Enqueue packets with underlying discipline (fifo)
  * but mark them with current time first.
  */
-static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+static int netem_add_packet(struct Qdisc *sch, struct sk_buff *skb)
 {
        struct netem_sched_data *q = qdisc_priv(sch);
        struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb;
        psched_time_t now;
        long delay;
 
-       pr_debug("netem_enqueue skb=%p @%lu\n", skb, jiffies);
-
-       /* Random packet drop 0 => none, ~0 => all */
-       if (q->loss && q->loss >= net_random()) {
-               sch->stats.drops++;
-               return 0;       /* lie about loss so TCP doesn't know */
-       }
-
-
        /* 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"
@@ -671,7 +663,7 @@
                sch->q.qlen++;
                sch->stats.bytes += skb->len;
                sch->stats.packets++;
-               return 0;
+               return NET_XMIT_SUCCESS;
        }
 
        sch->stats.drops++;
@@ -679,6 +671,31 @@
        return NET_XMIT_DROP;
 }
 
+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 @%lu\n", skb, jiffies);
+
+       /* Random packet drop 0 => none, ~0 => all */
+       if (q->loss && q->loss >= net_random()) {
+               pr_debug("netem_enqueue: random loss\n");
+               sch->stats.drops++;
+               return 0;       /* lie about loss so TCP doesn't know */
+       }
+
+       /* Random duplication */
+       if (q->duplicate && q->duplicate >= net_random()) {
+               struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+
+               pr_debug("netem_enqueue: dup %p\n", skb2);
+               if (skb2)
+                       netem_add_packet(sch, skb2);
+       }
+
+       return netem_add_packet(sch, skb);
+}
+
 /* Requeue packets but don't change time stamp */
 static int netem_requeue(struct sk_buff *skb, struct Qdisc *sch)
 {
@@ -806,6 +823,7 @@
                q->limit = qopt->limit;
                q->gap = qopt->gap;
                q->loss = qopt->loss;
+               q->duplicate = qopt->duplicate;
        }
        sch_tree_unlock(sch);
 
@@ -849,6 +867,7 @@
        qopt.limit = q->limit;
        qopt.loss = q->loss;
        qopt.gap = q->gap;
+       qopt.duplicate = q->duplicate;
 
        RTA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);