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authorPetr Machata <petrm@nvidia.com>2025-06-17 00:44:15 +0200
committerJakub Kicinski <kuba@kernel.org>2025-06-17 18:18:45 -0700
commit3365afd3abda5f6a54f4a822dad5c9314e94c3fc (patch)
treef8861bc8cfd7f661fc551a1d8d9b6363c3a5786c /net/ipv6
parentf78c75d84fe83898f0a00658f593d4f17b38cbc6 (diff)
downloadtip-3365afd3abda5f6a54f4a822dad5c9314e94c3fc.tar.gz
net: ipv6: ip6mr: Fix in/out netdev to pass to the FORWARD chain
The netfilter hook is invoked with skb->dev for input netdevice, and vif_dev for output netdevice. However at the point of invocation, skb->dev is already set to vif_dev, and MR-forwarded packets are reported with in=out: # ip6tables -A FORWARD -j LOG --log-prefix '[forw]' # cd tools/testing/selftests/net/forwarding # ./router_multicast.sh # dmesg | fgrep '[forw]' [ 1670.248245] [forw]IN=v5 OUT=v5 [...] For reference, IPv4 MR code shows in and out as appropriate. Fix by caching skb->dev and using the updated value for output netdev. Fixes: 7bc570c8b4f7 ("[IPV6] MROUTE: Support multicast forwarding.") Signed-off-by: Petr Machata <petrm@nvidia.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/3141ae8386fbe13fef4b793faa75e6bae58d798a.1750113335.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6mr.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 9db31e5b998c1a..426859cd340923 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2039,6 +2039,7 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
struct sk_buff *skb, int vifi)
{
struct vif_device *vif = &mrt->vif_table[vifi];
+ struct net_device *indev = skb->dev;
struct net_device *vif_dev;
struct ipv6hdr *ipv6h;
struct dst_entry *dst;
@@ -2101,7 +2102,7 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
IP6CB(skb)->flags |= IP6SKB_FORWARDED;
return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
- net, NULL, skb, skb->dev, vif_dev,
+ net, NULL, skb, indev, skb->dev,
ip6mr_forward2_finish);
out_free: