netfilter: nf_tables: unbind callbacks from flowtable destroy path

Callback unbinding needs to be done after nf_flow_table_free(),
otherwise entries are not removed from the hardware.

Update nft_unregister_flowtable_net_hooks() to call
nf_unregister_net_hook() instead since the commit/abort paths do not
deal with the callback unbinding anymore.

Add a comment to nft_flowtable_event() to clarify that
flow_offload_netdev_event() already removes the entries before the
callback unbinding.

Fixes: 8bb69f3b2918 ("netfilter: nf_tables: add flowtable offload control plane")
Fixes ff4bf2f42a40 ("netfilter: nf_tables: add nft_unregister_flowtable_hook()")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: wenxu <wenxu@ucloud.cn>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 273f383..43f05b3 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5984,6 +5984,7 @@ nft_flowtable_type_get(struct net *net, u8 family)
        return ERR_PTR(-ENOENT);
 }
 
+/* Only called from error and netdev event paths. */
 static void nft_unregister_flowtable_hook(struct net *net,
                                          struct nft_flowtable *flowtable,
                                          struct nft_hook *hook)
@@ -5999,7 +6000,7 @@ static void nft_unregister_flowtable_net_hooks(struct net *net,
        struct nft_hook *hook;
 
        list_for_each_entry(hook, &flowtable->hook_list, list)
-               nft_unregister_flowtable_hook(net, flowtable, hook);
+               nf_unregister_net_hook(net, &hook->ops);
 }
 
 static int nft_register_flowtable_net_hooks(struct net *net,
@@ -6448,12 +6449,14 @@ static void nf_tables_flowtable_destroy(struct nft_flowtable *flowtable)
 {
        struct nft_hook *hook, *next;
 
+       flowtable->data.type->free(&flowtable->data);
        list_for_each_entry_safe(hook, next, &flowtable->hook_list, list) {
+               flowtable->data.type->setup(&flowtable->data, hook->ops.dev,
+                                           FLOW_BLOCK_UNBIND);
                list_del_rcu(&hook->list);
                kfree(hook);
        }
        kfree(flowtable->name);
-       flowtable->data.type->free(&flowtable->data);
        module_put(flowtable->data.type->owner);
        kfree(flowtable);
 }
@@ -6497,6 +6500,7 @@ static void nft_flowtable_event(unsigned long event, struct net_device *dev,
                if (hook->ops.dev != dev)
                        continue;
 
+               /* flow_offload_netdev_event() cleans up entries for us. */
                nft_unregister_flowtable_hook(dev_net(dev), flowtable, hook);
                list_del_rcu(&hook->list);
                kfree_rcu(hook, rcu);