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

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

[Jeff Barnhill]

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@gmail.com>
---
 net/ipv6/ip6_output.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index b8ee50e94af3..2e891d2c30ef 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -375,6 +375,11 @@ static int ip6_forward_proxy_check(struct sk_buff *skb)
 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);
-- 
2.14.1

Re: [PATCH net] net/ipv6: Increment OUTxxx counters after netfilter hook

[David Miller]

From: Jeff Barnhill <0xeffeff@gmail.com>
Date: Thu,  5 Apr 2018 21:29:47 +0000

> 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@gmail.com>

Yep, this is more consistent with ipv4.

Applied, thank you.

Re: [PATCH net] net/ipv6: Increment OUTxxx counters after netfilter hook

[Sasha Levin]

Hi,

[This is an automated email]

This commit has been processed by the -stable helper bot and determined
to be a high probability candidate for -stable trees. (score: 5.8567)

The bot has tested the following trees: v4.16.1, v4.15.16, v4.14.33, v4.9.93, v4.4.127.

v4.16.1: Build OK!
v4.15.16: Build OK!
v4.14.33: Build OK!
v4.9.93: Build OK!
v4.4.127: Failed to apply! Possible dependencies:
    1d0155035918 ("ipv6: rename IP6_INC_STATS_BH()")


Please let us know if you'd like to have this patch included in a stable tree.

Re: [PATCH net] net/ipv6: Increment OUTxxx counters after netfilter hook

[Sasha Levin]

Hi,

[This is an automated email]

This commit has been processed by the -stable helper bot and determined
to be a high probability candidate for -stable trees. (score: 5.8567)

The bot has tested the following trees: v4.16.1, v4.15.16, v4.14.33, v4.9.93, v4.4.127.

v4.16.1: Build OK!
v4.15.16: Build OK!
v4.14.33: Build OK!
v4.9.93: Build OK!
v4.4.127: Failed to apply! Possible dependencies:
    1d0155035918 ("ipv6: rename IP6_INC_STATS_BH()")


Please let us know if you'd like to have this patch included in a stable tree.

--
Thanks,
Sasha