[PATCH 4.16 04/18] net/ipv6: Increment OUTxxx counters after netfilter hook

From: Greg Kroah-Hartman
Date: Tue Apr 10 2018 - 18:24:23 EST


4.16-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jeff Barnhill <0xeffeff@xxxxxxxxx>


[ Upstream commit 71a1c915238c970cd9bdd5bf158b1279d6b6d55b ]

At the end of ip6_forward(), IPSTATS_MIB_OUTFORWDATAGRAMS and
IPSTATS_MIB_OUTOCTETS are incremented immediately before the NF_HOOK call
for NFPROTO_IPV6 / NF_INET_FORWARD. As a result, these counters get
incremented regardless of whether or not the netfilter hook allows the
packet to continue being processed. This change increments the counters
in ip6_forward_finish() so that it will not happen if the netfilter hook
chooses to terminate the packet, which is similar to how IPv4 works.

Signed-off-by: Jeff Barnhill <0xeffeff@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ip6_output.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -375,6 +375,11 @@ static int ip6_forward_proxy_check(struc
static inline int ip6_forward_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
+ struct dst_entry *dst = skb_dst(skb);
+
+ __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
+ __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
+
return dst_output(net, sk, skb);
}

@@ -569,8 +574,6 @@ int ip6_forward(struct sk_buff *skb)

hdr->hop_limit--;

- __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
- __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
net, NULL, skb, skb->dev, dst->dev,
ip6_forward_finish);