Commit 2edc1a38 authored by Menglong Dong's avatar Menglong Dong Committed by David S. Miller
Browse files

net: ip: add skb drop reasons to ip forwarding 



Replace kfree_skb() which is used in ip6_forward() and ip_forward()
with kfree_skb_reason().

The new drop reason 'SKB_DROP_REASON_PKT_TOO_BIG' is introduced for
the case that the length of the packet exceeds MTU and can't
fragment.

Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Reviewed-by: default avatarJiang Biao <benbjiang@tencent.com>
Reviewed-by: default avatarHao Peng <flyingpeng@tencent.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3ae42cc8

include/linux/skbuff.h

+3 −0
Original line number Diff line number Diff line
@@ -453,6 +453,9 @@ enum skb_drop_reason { 
	SKB_DROP_REASON_IP_INNOROUTES,	/* network unreachable, corresponding

					 * to IPSTATS_MIB_INADDRERRORS

					 */

	SKB_DROP_REASON_PKT_TOO_BIG,	/* packet size is too big (maybe exceed

					 * the MTU)

					 */

	SKB_DROP_REASON_MAX,

};

include/trace/events/skb.h

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ 
	EM(SKB_DROP_REASON_INVALID_PROTO, INVALID_PROTO)	\

	EM(SKB_DROP_REASON_IP_INADDRERRORS, IP_INADDRERRORS)	\

	EM(SKB_DROP_REASON_IP_INNOROUTES, IP_INNOROUTES)	\

	EM(SKB_DROP_REASON_PKT_TOO_BIG, PKT_TOO_BIG)		\

	EMe(SKB_DROP_REASON_MAX, MAX)



#undef EM

net/ipv4/ip_forward.c

+10 −3
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ int ip_forward(struct sk_buff *skb) 
	struct rtable *rt;	/* Route we use */

	struct ip_options *opt	= &(IPCB(skb)->opt);

	struct net *net;

	SKB_DR(reason);



	/* that should never happen */

	if (skb->pkt_type != PACKET_HOST)
@@ -101,8 +102,10 @@ int ip_forward(struct sk_buff *skb) 
	if (skb_warn_if_lro(skb))

		goto drop;



	if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb))

	if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb)) {

		SKB_DR_SET(reason, XFRM_POLICY);

		goto drop;

	}



	if (IPCB(skb)->opt.router_alert && ip_call_ra_chain(skb))

		return NET_RX_SUCCESS;
@@ -118,8 +121,10 @@ int ip_forward(struct sk_buff *skb) 
	if (ip_hdr(skb)->ttl <= 1)

		goto too_many_hops;



	if (!xfrm4_route_forward(skb))

	if (!xfrm4_route_forward(skb)) {

		SKB_DR_SET(reason, XFRM_POLICY);

		goto drop;

	}



	rt = skb_rtable(skb);
@@ -132,6 +137,7 @@ int ip_forward(struct sk_buff *skb) 
		IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);

		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,

			  htonl(mtu));

		SKB_DR_SET(reason, PKT_TOO_BIG);

		goto drop;

	}
@@ -169,7 +175,8 @@ int ip_forward(struct sk_buff *skb) 
	/* Tell the sender its packet died... */

	__IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);

	icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);

	SKB_DR_SET(reason, IP_INHDR);

drop:

	kfree_skb(skb);

	kfree_skb_reason(skb, reason);

	return NET_RX_DROP;

}

net/ipv6/ip6_output.c

+6 −3
Original line number Diff line number Diff line
@@ -469,6 +469,7 @@ int ip6_forward(struct sk_buff *skb) 
	struct inet6_skb_parm *opt = IP6CB(skb);

	struct net *net = dev_net(dst->dev);

	struct inet6_dev *idev;

	SKB_DR(reason);

	u32 mtu;



	idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
@@ -518,7 +519,7 @@ int ip6_forward(struct sk_buff *skb) 
		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);



		kfree_skb(skb);

		kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);

		return -ETIMEDOUT;

	}
@@ -537,6 +538,7 @@ int ip6_forward(struct sk_buff *skb) 


	if (!xfrm6_route_forward(skb)) {

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);

		SKB_DR_SET(reason, XFRM_POLICY);

		goto drop;

	}

	dst = skb_dst(skb);
@@ -596,7 +598,7 @@ int ip6_forward(struct sk_buff *skb) 
		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS);

		__IP6_INC_STATS(net, ip6_dst_idev(dst),

				IPSTATS_MIB_FRAGFAILS);

		kfree_skb(skb);

		kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);

		return -EMSGSIZE;

	}
@@ -618,8 +620,9 @@ int ip6_forward(struct sk_buff *skb) 


error:

	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);

	SKB_DR_SET(reason, IP_INADDRERRORS);

drop:

	kfree_skb(skb);

	kfree_skb_reason(skb, reason);

	return -EINVAL;

}