The egress device in the tuple is obtained from route. Use
dev_fill_forward_path() instead to provide the real ingress device for
this flow whenever this is available.

Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
v2: no changes.

 include/net/netfilter/nf_flow_table.h |  4 ++++
 net/netfilter/nf_flow_table_core.c    |  1 +
 net/netfilter/nf_flow_table_ip.c      | 25 +++++++++++++++++++++++--
 net/netfilter/nft_flow_offload.c      |  1 +
 4 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/include/net/netfilter/nf_flow_table.h 
b/include/net/netfilter/nf_flow_table.h
index ecb84d4358cc..fe225e881cc7 100644
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -117,6 +117,7 @@ struct flow_offload_tuple {
        u8                              dir;
        enum flow_offload_xmit_type     xmit_type:8;
        u16                             mtu;
+       u32                             oifidx;
 
        struct dst_entry                *dst_cache;
 };
@@ -164,6 +165,9 @@ struct nf_flow_route {
                struct {
                        u32             ifindex;
                } in;
+               struct {
+                       u32             ifindex;
+               } out;
                struct dst_entry        *dst;
        } tuple[FLOW_OFFLOAD_DIR_MAX];
 };
diff --git a/net/netfilter/nf_flow_table_core.c 
b/net/netfilter/nf_flow_table_core.c
index 66abc7f287a3..99f01f08c550 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -94,6 +94,7 @@ static int flow_offload_fill_route(struct flow_offload *flow,
        }
 
        flow_tuple->iifidx = route->tuple[dir].in.ifindex;
+       flow_tuple->oifidx = route->tuple[dir].out.ifindex;
 
        if (dst_xfrm(dst))
                flow_tuple->xmit_type = FLOW_OFFLOAD_XMIT_XFRM;
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index e215c79e6777..92f444db8d9f 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -228,6 +228,15 @@ static int nf_flow_offload_dst_check(struct dst_entry *dst)
        return 0;
 }
 
+static struct net_device *nf_flow_outdev_lookup(struct net *net, int oifidx,
+                                               struct net_device *dev)
+{
+       if (oifidx == dev->ifindex)
+               return dev;
+
+       return dev_get_by_index_rcu(net, oifidx);
+}
+
 static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
                                      const struct nf_hook_state *state,
                                      struct dst_entry *dst)
@@ -267,7 +276,6 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
        dir = tuplehash->tuple.dir;
        flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
        rt = (struct rtable *)flow->tuplehash[dir].tuple.dst_cache;
-       outdev = rt->dst.dev;
 
        if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
                return NF_ACCEPT;
@@ -286,6 +294,13 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
                return NF_ACCEPT;
        }
 
+       outdev = nf_flow_outdev_lookup(state->net, tuplehash->tuple.oifidx,
+                                      rt->dst.dev);
+       if (!outdev) {
+               flow_offload_teardown(flow);
+               return NF_ACCEPT;
+       }
+
        if (nf_flow_nat_ip(flow, skb, thoff, dir) < 0)
                return NF_DROP;
 
@@ -517,7 +532,6 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
        dir = tuplehash->tuple.dir;
        flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
        rt = (struct rt6_info *)flow->tuplehash[dir].tuple.dst_cache;
-       outdev = rt->dst.dev;
 
        if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
                return NF_ACCEPT;
@@ -533,6 +547,13 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
                return NF_ACCEPT;
        }
 
+       outdev = nf_flow_outdev_lookup(state->net, tuplehash->tuple.oifidx,
+                                      rt->dst.dev);
+       if (!outdev) {
+               flow_offload_teardown(flow);
+               return NF_ACCEPT;
+       }
+
        if (skb_try_make_writable(skb, sizeof(*ip6h)))
                return NF_DROP;
 
diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 4b476b0a3c88..6a6633e2ceeb 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -84,6 +84,7 @@ static int nft_dev_forward_path(struct nf_flow_route *route,
        }
 
        route->tuple[!dir].in.ifindex = info.iifindex;
+       route->tuple[dir].out.ifindex = info.iifindex;
 
        return 0;
 }
-- 
2.20.1

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