From: Florian Westphal Date: Mon, 11 May 2015 17:50:41 +0000 (+0200) Subject: net: sched: use counter to break reclassify loops X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e578d9c02587d57bfa7b560767c698a668a468c6;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git net: sched: use counter to break reclassify loops 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 Signed-off-by: Florian Westphal Acked-by: Alexei Starovoitov Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- diff --git a/Documentation/networking/tc-actions-env-rules.txt b/Documentation/networking/tc-actions-env-rules.txt index 95c71716b2e2..f37814693ad3 100644 --- a/Documentation/networking/tc-actions-env-rules.txt +++ b/Documentation/networking/tc-actions-env-rules.txt @@ -8,10 +8,6 @@ For example if your action queues a packet to be processed later, or intentionally branches by redirecting a packet, then you need to clone the packet. -There are certain fields in the skb tc_verd that need to be reset so we -avoid loops, etc. A few are generic enough that skb_act_clone() -resets them for you, so invoke skb_act_clone() rather than skb_clone(). - 2) If you munge any packet thou shalt call pskb_expand_head in the case someone else is referencing the skb. After that you "own" the skb. diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 1b0a2e88ed2b..2738f6f87908 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -739,21 +739,6 @@ static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen) return rtab->data[slot]; } -#ifdef CONFIG_NET_CLS_ACT -static inline struct sk_buff *skb_act_clone(struct sk_buff *skb, gfp_t gfp_mask, - int action) -{ - struct sk_buff *n; - - n = skb_clone(skb, gfp_mask); - - if (n) { - n->tc_verd = SET_TC_VERD(n->tc_verd, 0); - } - return n; -} -#endif - struct psched_ratecfg { u64 rate_bytes_ps; /* bytes per second */ u32 mult; diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h index 596ffa0c7084..ffc112c8e1c2 100644 --- a/include/uapi/linux/pkt_cls.h +++ b/include/uapi/linux/pkt_cls.h @@ -44,13 +44,13 @@ bits 9,10,11: redirect counter - redirect TTL. Loop avoidance #define TC_OK2MUNGE _TC_MAKEMASK1(1) #define SET_TC_OK2MUNGE(v) ( TC_OK2MUNGE | (v & ~TC_OK2MUNGE)) #define CLR_TC_OK2MUNGE(v) ( v & ~TC_OK2MUNGE) -#endif #define S_TC_VERD _TC_MAKE32(2) #define M_TC_VERD _TC_MAKEMASK(4,S_TC_VERD) #define G_TC_VERD(x) _TC_GETVALUE(x,S_TC_VERD,M_TC_VERD) #define V_TC_VERD(x) _TC_MAKEVALUE(x,S_TC_VERD) #define SET_TC_VERD(v,n) ((V_TC_VERD(n)) | (v & ~M_TC_VERD)) +#endif #define S_TC_FROM _TC_MAKE32(6) #define M_TC_FROM _TC_MAKEMASK(2,S_TC_FROM) diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index 3f63ceac8e01..a42a3b257226 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -151,7 +151,7 @@ static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, } at = G_TC_AT(skb->tc_verd); - skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action); + skb2 = skb_clone(skb, GFP_ATOMIC); if (skb2 == NULL) goto out; diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index ad9eed70bc8f..0b74dc0ede9c 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -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