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@xxxxxxxxxx>
---
net/bridge/br_netfilter_hooks.c | 30 +-----------------------------
1 file changed, 1 insertion(+), 29 deletions(-)
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 451e45b9a6a5..94cbe967d1c1 100644
--- 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);
--
2.47.1
