[PATCH net-next 04/14] netfilter: nf_tables: Store user-defined hook ifname

[Pablo Neira Ayuso <pablo@netfilter.org>]

From: Phil Sutter <phil@nwl.cc>

Prepare for hooks with NULL ops.dev pointer (due to non-existent device)
and store the interface name and length as specified by the user upon
creation. No functional change intended.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_tables.h |  2 ++
 net/netfilter/nf_tables_api.c     | 10 +++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 7dcea247f853..d1f274af5b70 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1198,6 +1198,8 @@ struct nft_hook {
 	struct list_head	list;
 	struct nf_hook_ops	ops;
 	struct rcu_head		rcu;
+	char			ifname[IFNAMSIZ];
+	u8			ifnamelen;
 };
 
 /**
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index e41c77e5eefd..95d8d33589b1 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2276,7 +2276,6 @@ static struct nft_hook *nft_netdev_hook_alloc(struct net *net,
 					      const struct nlattr *attr)
 {
 	struct net_device *dev;
-	char ifname[IFNAMSIZ];
 	struct nft_hook *hook;
 	int err;
 
@@ -2286,12 +2285,17 @@ static struct nft_hook *nft_netdev_hook_alloc(struct net *net,
 		goto err_hook_alloc;
 	}
 
-	nla_strscpy(ifname, attr, IFNAMSIZ);
+	err = nla_strscpy(hook->ifname, attr, IFNAMSIZ);
+	if (err < 0)
+		goto err_hook_dev;
+
+	hook->ifnamelen = nla_len(attr);
+
 	/* nf_tables_netdev_event() is called under rtnl_mutex, this is
 	 * indirectly serializing all the other holders of the commit_mutex with
 	 * the rtnl_mutex.
 	 */
-	dev = __dev_get_by_name(net, ifname);
+	dev = __dev_get_by_name(net, hook->ifname);
 	if (!dev) {
 		err = -ENOENT;
 		goto err_hook_dev;
-- 
2.30.2