nexthop: Allow setting "offload" and "trap" indication of nexthop buckets

Add a function that can be called by device drivers to set "offload" or
"trap" indication on nexthop buckets following nexthop notifications and
other changes such as a neighbour becoming invalid.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/nexthop.h

@@ -220,6 +220,8 @@ int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
 			      struct netlink_ext_ack *extack);
 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
+void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
+				 bool offload, bool trap);
 
 /* caller is holding rcu or rtnl; no reference taken to nexthop */
 struct nexthop *nexthop_find_by_id(struct net *net, u32 id);

net/ipv4/nexthop.c

@@ -3072,6 +3072,40 @@ void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap)
 }
 EXPORT_SYMBOL(nexthop_set_hw_flags);
 
+void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
+				 bool offload, bool trap)
+{
+	struct nh_res_table *res_table;
+	struct nh_res_bucket *bucket;
+	struct nexthop *nexthop;
+	struct nh_group *nhg;
+
+	rcu_read_lock();
+
+	nexthop = nexthop_find_by_id(net, id);
+	if (!nexthop || !nexthop->is_group)
+		goto out;
+
+	nhg = rcu_dereference(nexthop->nh_grp);
+	if (!nhg->resilient)
+		goto out;
+
+	if (bucket_index >= nhg->res_table->num_nh_buckets)
+		goto out;
+
+	res_table = rcu_dereference(nhg->res_table);
+	bucket = &res_table->nh_buckets[bucket_index];
+	bucket->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
+	if (offload)
+		bucket->nh_flags |= RTNH_F_OFFLOAD;
+	if (trap)
+		bucket->nh_flags |= RTNH_F_TRAP;
+
+out:
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(nexthop_bucket_set_hw_flags);
+
 static void __net_exit nexthop_net_exit(struct net *net)
 {
 	rtnl_lock();