[PATCH bpf-next v2 2/5] netkit: Simplify netkit mode over to use NLA_POLICY_MAX

[Daniel Borkmann <daniel@iogearbox.net>]

Jakub suggested to rely on netlink policy validation via NLA_POLICY_MAX()
instead of open-coding it. netkit_check_mode() is a candidate which can
be simplified through this as well aside from the netkit scrubbing one.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
---
 v1 -> v2:
   - new patch, also use NLA_POLICY_MAX here (Jakub)

 drivers/net/netkit.c | 25 +++----------------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index fba2c734f0ec..cd8360b9bbde 100644
--- a/drivers/net/netkit.c
+++ b/drivers/net/netkit.c
@@ -311,20 +311,6 @@ static int netkit_check_policy(int policy, struct nlattr *tb,
 	}
 }
 
-static int netkit_check_mode(int mode, struct nlattr *tb,
-			     struct netlink_ext_ack *extack)
-{
-	switch (mode) {
-	case NETKIT_L2:
-	case NETKIT_L3:
-		return 0;
-	default:
-		NL_SET_ERR_MSG_ATTR(extack, tb,
-				    "Provided device mode can only be L2 or L3");
-		return -EINVAL;
-	}
-}
-
 static int netkit_validate(struct nlattr *tb[], struct nlattr *data[],
 			   struct netlink_ext_ack *extack)
 {
@@ -360,13 +346,8 @@ static int netkit_new_link(struct net *src_net, struct net_device *dev,
 	int err;
 
 	if (data) {
-		if (data[IFLA_NETKIT_MODE]) {
-			attr = data[IFLA_NETKIT_MODE];
-			mode = nla_get_u32(attr);
-			err = netkit_check_mode(mode, attr, extack);
-			if (err < 0)
-				return err;
-		}
+		if (data[IFLA_NETKIT_MODE])
+			mode = nla_get_u32(data[IFLA_NETKIT_MODE]);
 		if (data[IFLA_NETKIT_PEER_INFO]) {
 			attr = data[IFLA_NETKIT_PEER_INFO];
 			ifmp = nla_data(attr);
@@ -976,7 +957,7 @@ static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev)
 
 static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = {
 	[IFLA_NETKIT_PEER_INFO]		= { .len = sizeof(struct ifinfomsg) },
-	[IFLA_NETKIT_MODE]		= { .type = NLA_U32 },
+	[IFLA_NETKIT_MODE]		= NLA_POLICY_MAX(NLA_U32, NETKIT_L3),
 	[IFLA_NETKIT_POLICY]		= { .type = NLA_U32 },
 	[IFLA_NETKIT_PEER_POLICY]	= { .type = NLA_U32 },
 	[IFLA_NETKIT_SCRUB]		= NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT),
-- 
2.43.0