netfilter: flowtable: remove dying bit, use teardown bit instead

The dying bit removes the conntrack entry if the netdev that owns this
flow is going down. Instead, use the teardown mechanism to push back the
flow to conntrack to let the classic software path decide what to do
with it.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_flow_table.h

@@ -85,7 +85,6 @@ struct flow_offload_tuple_rhash {
 
 #define FLOW_OFFLOAD_SNAT	0x1
 #define FLOW_OFFLOAD_DNAT	0x2
-#define FLOW_OFFLOAD_DYING	0x4
 #define FLOW_OFFLOAD_TEARDOWN	0x8
 #define FLOW_OFFLOAD_HW		0x10
 #define FLOW_OFFLOAD_HW_DYING	0x20
@@ -134,10 +133,6 @@ int nf_flow_table_init(struct nf_flowtable *flow_table);
 void nf_flow_table_free(struct nf_flowtable *flow_table);
 
 void flow_offload_teardown(struct flow_offload *flow);
-static inline void flow_offload_dead(struct flow_offload *flow)
-{
-	flow->flags |= FLOW_OFFLOAD_DYING;
-}
 
 int nf_flow_snat_port(const struct flow_offload *flow,
 		      struct sk_buff *skb, unsigned int thoff,

net/netfilter/nf_flow_table_core.c

@@ -182,8 +182,6 @@ void flow_offload_free(struct flow_offload *flow)
 	default:
 		break;
 	}
-	if (flow->flags & FLOW_OFFLOAD_DYING)
-		nf_ct_delete(flow->ct, 0, 0);
 	nf_ct_put(flow->ct);
 	kfree_rcu(flow, rcu_head);
 }
@@ -300,7 +298,7 @@ flow_offload_lookup(struct nf_flowtable *flow_table,
 
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
-	if (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN))
+	if (flow->flags & FLOW_OFFLOAD_TEARDOWN)
 		return NULL;
 
 	if (unlikely(nf_ct_is_dying(flow->ct)))
@@ -349,7 +347,7 @@ static void nf_flow_offload_gc_step(struct flow_offload *flow, void *data)
 	struct nf_flowtable *flow_table = data;
 
 	if (nf_flow_has_expired(flow) || nf_ct_is_dying(flow->ct) ||
-	    (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN))) {
+	    (flow->flags & FLOW_OFFLOAD_TEARDOWN)) {
 		if (flow->flags & FLOW_OFFLOAD_HW) {
 			if (!(flow->flags & FLOW_OFFLOAD_HW_DYING))
 				nf_flow_offload_del(flow_table, flow);
@@ -523,7 +521,7 @@ static void nf_flow_table_do_cleanup(struct flow_offload *flow, void *data)
 	if (net_eq(nf_ct_net(flow->ct), dev_net(dev)) &&
 	    (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
 	     flow->tuplehash[1].tuple.iifidx == dev->ifindex))
-		flow_offload_dead(flow);
+		flow_offload_teardown(flow);
 }
 
 static void nf_flow_table_iterate_cleanup(struct nf_flowtable *flowtable,