netfilter: br_netfilter: remove unused conditional and dead code

The SKB_DROP_REASON_IP_INADDRERRORS drop reason is never returned from
any function, as such it cannot be returned from the ip_route_input call
tree. The 'reason != SKB_DROP_REASON_IP_INADDRERRORS' conditional is
thus always true.

Looking back at history, commit 50038bf38e65 ("net: ip: make
ip_route_input() return drop reasons") changed the ip_route_input
returned value check in br_nf_pre_routing_finish from -EHOSTUNREACH to
SKB_DROP_REASON_IP_INADDRERRORS. It turns out -EHOSTUNREACH could not be
returned either from the ip_route_input call tree and this since commit
251da4130115 ("ipv4: Cache ip_error() routes even when not
forwarding.").

Not a fix as this won't change the behavior. While at it use
kfree_skb_reason.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 451e45b9a6a5de37f2e5209a0740d78676fcfd4f..94cbe967d1c163f9b5aadcad8569ba3968842fdc 100644 (file)
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -393,38 +393,10 @@ static int br_nf_pre_routing_finish(struct net *net, struct sock *sk, struct sk_
                reason = ip_route_input(skb, iph->daddr, iph->saddr,
                                        ip4h_dscp(iph), dev);
                if (reason) {
-                       struct in_device *in_dev = __in_dev_get_rcu(dev);
-
-                       /* If err equals -EHOSTUNREACH the error is due to a
-                        * martian destination or due to the fact that
-                        * forwarding is disabled. For most martian packets,
-                        * ip_route_output_key() will fail. It won't fail for 2 types of
-                        * martian destinations: loopback destinations and destination
-                        * 0.0.0.0. In both cases the packet will be dropped because the
-                        * destination is the loopback device and not the bridge. */
-                       if (reason != SKB_DROP_REASON_IP_INADDRERRORS || !in_dev ||
-                           IN_DEV_FORWARD(in_dev))
-                               goto free_skb;
-
-                       rt = ip_route_output(net, iph->daddr, 0,
-                                            ip4h_dscp(iph), 0,
-                                            RT_SCOPE_UNIVERSE);
-                       if (!IS_ERR(rt)) {
-                               /* - Bridged-and-DNAT'ed traffic doesn't
-                                *   require ip_forwarding. */
-                               if (rt->dst.dev == dev) {
-                                       skb_dst_drop(skb);
-                                       skb_dst_set(skb, &rt->dst);
-                                       goto bridged_dnat;
-                               }
-                               ip_rt_put(rt);
-                       }
-free_skb:
-                       kfree_skb(skb);
+                       kfree_skb_reason(skb, reason);
                        return 0;
                } else {
                        if (skb_dst(skb)->dev == dev) {
-bridged_dnat:
                                skb->dev = br_indev;
                                nf_bridge_update_protocol(skb);
                                nf_bridge_push_encap_header(skb);