4.9-stable review patch. If anyone has any objections, please let me know.
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From: Miguel Fadon Perlines mfadon@teldat.com
[ Upstream commit 58b35f27689b5eb514fc293c332966c226b1b6e4 ]
arp_filter performs an ip_route_output search for arp source address and checks if output device is the same where the arp request was received, if it is not, the arp request is not answered.
This route lookup is always done on main route table so l3slave devices never find the proper route and arp is not answered.
Passing l3mdev_master_ifindex_rcu(dev) return value as oif fixes the lookup for l3slave devices while maintaining same behavior for non l3slave devices as this function returns 0 in that case.
Fixes: 613d09b30f8b ("net: Use VRF device index for lookups on TX") Signed-off-by: Miguel Fadon Perlines mfadon@teldat.com Acked-by: David Ahern dsa@cumulusnetworks.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/arp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -437,7 +437,7 @@ static int arp_filter(__be32 sip, __be32 /*unsigned long now; */ struct net *net = dev_net(dev);
- rt = ip_route_output(net, sip, tip, 0, 0); + rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev)); if (IS_ERR(rt)) return 1; if (rt->dst.dev != dev) {