On 12/27/18 2:38 AM, wenxu@ucloud.cn wrote:

From: wenxu <redacted>

In the ip_rcv the skb go through the PREROUTING hook first,
Then jump in vrf device go through the same hook again.
When conntrack work with vrf, there will be some conflict for rules.
Because the package go through the hook twice with different nf status

ip link add user1 type vrf table 1
ip link add user2 type vrf table 2
ip l set dev tun1 master user1
ip l set dev tun2 master user2

nft add table firewall
nft add chain firewall zones { type filter hook prerouting  priority - 300 \; }
nft add rule firewall zones counter ct zone set iif map { "tun1" : 1, "tun2" : 2 }
nft add chain firewall rule-1000-ingress
nft add rule firewall rule-1000-ingress ct zone 1 tcp dport 22 ct state new counter accept
nft add rule firewall rule-1000-ingress counter drop
nft add chain firewall rule-1000-egress
nft add rule firewall rule-1000-egress tcp dport 22 ct state new counter drop
nft add rule firewall rule-1000-egress counter accept

nft add chain firewall rules-all { type filter hook prerouting priority - 150 \; }
nft add rule firewall rules-all ip daddr vmap { "2.2.2.11" : jump rule-1000-ingress }
nft add rule firewall rules-all ct zone vmap { 1 : jump rule-1000-egress }

nft add rule firewall dnat-all ct zone vmap { 1 : jump dnat-1000 }
nft add rule firewall dnat-1000 ip daddr 2.2.2.11 counter dnat to 10.0.0.7

For a package with ip daddr 2.2.2.11 and tcp dport 22, first time accept in the 
rule-1000-ingress and dnat to 10.0.0.7. Then second time the packet goto the wrong 
chain rule-1000-egress which leads the packet drop

So it proived a flag to control the vrf-device bypass go through hook for 
the second time.

Signed-off-by: wenxu <redacted>
---
 drivers/net/vrf.c            | 20 ++++++++++++++++++--
 include/uapi/linux/if_link.h |  3 +++
 2 files changed, 21 insertions(+), 2 deletions(-)

Thanks for the report with commands to reproduce. I am out of the office
at the moment; I will take a look at this next week.