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net: sched: use counter to break reclassify loops

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Seems all we want here is to avoid endless 'goto reclassify' loop.
tc_classify_compat even resets this counter when something other
than TC_ACT_RECLASSIFY is returned, so this skb-counter doesn't
break hypothetical loops induced by something other than perpetual
TC_ACT_RECLASSIFY return values.

skb_act_clone is now identical to skb_clone, so just use that.

Tested with following (bogus) filter:
tc filter add dev eth0 parent ffff: \
 protocol ip u32 match u32 0 0 police rate 10Kbit burst \
 64000 mtu 1500 action reclassify

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal
2015-05-11 19:50:41 +02:00
committed by David S. Miller
parent b04096ff33
commit e578d9c025
5 changed files with 5 additions and 30 deletions
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12
net/sched/sch_api.c
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@@ -1816,13 +1816,8 @@ int tc_classify_compat(struct sk_buff *skb, const struct tcf_proto *tp,
continue;
err = tp->classify(skb, tp, res);
if (err >= 0) {
#ifdef CONFIG_NET_CLS_ACT
if (err != TC_ACT_RECLASSIFY && skb->tc_verd)
skb->tc_verd = SET_TC_VERD(skb->tc_verd, 0);
#endif
if (err >= 0)
return err;
}
}
return -1;
}
@@ -1834,23 +1829,22 @@ int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
int err = 0;
#ifdef CONFIG_NET_CLS_ACT
const struct tcf_proto *otp = tp;
int limit = 0;
reclassify:
#endif
err = tc_classify_compat(skb, tp, res);
#ifdef CONFIG_NET_CLS_ACT
if (err == TC_ACT_RECLASSIFY) {
u32 verd = G_TC_VERD(skb->tc_verd);
tp = otp;
if (verd++ >= MAX_REC_LOOP) {
if (unlikely(limit++ >= MAX_REC_LOOP)) {
net_notice_ratelimited("%s: packet reclassify loop rule prio %u protocol %02x\n",
tp->q->ops->id,
tp->prio & 0xffff,
ntohs(tp->protocol));
return TC_ACT_SHOT;
}
skb->tc_verd = SET_TC_VERD(skb->tc_verd, verd);
goto reclassify;
}
#endif