On 1/10/19 10:53 PM, we...@ucloud.cn wrote:
> From: wenxu <we...@ucloud.cn>
>
> 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 dnat 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 This patch avoid already dnat packet go through the prerouting hook for the
> second time.
>
> Signed-off-by: wenxu <we...@ucloud.cn>
> ---
> drivers/net/vrf.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
> index 95909e2..e61a045 100644
> --- a/drivers/net/vrf.c
> +++ b/drivers/net/vrf.c
> @@ -37,6 +37,7 @@
> #include <net/l3mdev.h>
> #include <net/fib_rules.h>
> #include <net/netns/generic.h>
> +#include <net/netfilter/nf_conntrack.h>
>
> #define DRV_NAME "vrf"
> #define DRV_VERSION "1.0"
> @@ -898,6 +899,12 @@ static struct sk_buff *vrf_rcv_nfhook(u8 pf, unsigned
> int hook,
> struct net_device *dev)
> {
> struct net *net = dev_net(dev);
> + enum ip_conntrack_info ctinfo;
> + struct nf_conn *ct;
> +
> + ct = nf_ct_get(skb, &ctinfo);
> + if (ct && (ct->status & IPS_DST_NAT))
> + return skb;
>
> if (nf_hook(pf, hook, net, NULL, skb, dev, NULL, vrf_rcv_finish) != 1)
> skb = NULL; /* kfree_skb(skb) handled by nf code */
>
That looks better to me. I am not familiar enough with netfilter
internals to know if this is acceptable; you should cc the netfilter
list to get opinions.
And for this to go into net and back to stable releases, you need a
Fixes tag:
Fixes: 73e20b761acf8 ("net: vrf: Add support for PREROUTING rules on vrf
device")
