[PKT_SCHED] dsmark: handle cloned and non-linear skb's
Make dsmark work properly with non-linear and cloned skb's
Before modifying the header, it needs to check that skb header is
writeable.
Note: this makes the assumption, that if it queues a good skb
then a good skb will come out of the embedded qdisc.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index d96eaf0..ad30b7b 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -187,13 +187,19 @@
pr_debug("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
if (p->set_tc_index) {
- /* FIXME: Safe with non-linear skbs? --RR */
switch (skb->protocol) {
case __constant_htons(ETH_P_IP):
+ if (skb_cow_head(skb, sizeof(struct iphdr)))
+ goto drop;
+
skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
& ~INET_ECN_MASK;
break;
+
case __constant_htons(ETH_P_IPV6):
+ if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
+ goto drop;
+
skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
& ~INET_ECN_MASK;
break;
@@ -217,14 +223,14 @@
case TC_ACT_STOLEN:
kfree_skb(skb);
return NET_XMIT_SUCCESS;
+
case TC_ACT_SHOT:
- kfree_skb(skb);
- sch->qstats.drops++;
- return NET_XMIT_BYPASS;
+ goto drop;
#endif
case TC_ACT_OK:
skb->tc_index = TC_H_MIN(res.classid);
break;
+
default:
if (p->default_index != NO_DEFAULT_INDEX)
skb->tc_index = p->default_index;
@@ -243,6 +249,11 @@
sch->q.qlen++;
return NET_XMIT_SUCCESS;
+
+drop:
+ kfree_skb(skb);
+ sch->qstats.drops++;
+ return NET_XMIT_BYPASS;
}
static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)