Commit bba98083 authored by Menglong Dong's avatar Menglong Dong Committed by David S. Miller
Browse files

net: ipv6: remove redundant statistics in ipv6_hop_jumbo() 



There are two call chains for ipv6_hop_jumbo(). The first one is:

ipv6_destopt_rcv() -> ip6_parse_tlv() -> ipv6_hop_jumbo()

On this call chain, the drop statistics will be done in
ipv6_destopt_rcv() with 'IPSTATS_MIB_INHDRERRORS' if ipv6_hop_jumbo()
returns false.

The second call chain is:

ip6_rcv_core() -> ipv6_parse_hopopts() -> ip6_parse_tlv()

And the drop statistics will also be done in ip6_rcv_core() with
'IPSTATS_MIB_INHDRERRORS' if ipv6_hop_jumbo() returns false.

Therefore, the statistics in ipv6_hop_jumbo() is redundant, which
means the drop is counted twice. The statistics in ipv6_hop_jumbo()
is almost the same as the outside, except the
'IPSTATS_MIB_INTRUNCATEDPKTS', which seems that we have to ignore it.

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 1ad6d548

net/ipv6/exthdrs.c

+1 −8
Original line number Diff line number Diff line
@@ -994,33 +994,26 @@ static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 
static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)

{

	const unsigned char *nh = skb_network_header(skb);

	struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);

	struct net *net = ipv6_skb_net(skb);

	u32 pkt_len;



	if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {

		net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",

				    nh[optoff+1]);

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);

		goto drop;

	}



	pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));

	if (pkt_len <= IPV6_MAXPLEN) {

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);

		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);

		return false;

	}

	if (ipv6_hdr(skb)->payload_len) {

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);

		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);

		return false;

	}



	if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);

	if (pkt_len > skb->len - sizeof(struct ipv6hdr))

		goto drop;

	}



	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))

		goto drop;