netlink: specs: fou: local-v4 and peer-v4 are big endian

fou_core.c uses nla_get_in_addr() / nla_put_in_addr() on both, i.e.
they are __be32, and port / peer-port in the same spec are already
annotated. Without byte-order YNL swaps them on little endian hosts.

The generated policy goes from NLA_U32 to NLA_BE32, which changes
nothing: lib/nlattr.c gives the two the same length in nla_attr_len[]
and the same range handling, and neither attribute has a range check.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://patch.msgid.link/20260904191412.3872344-3-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Documentation/netlink/specs/fou.yaml

@@ -50,6 +50,7 @@ attribute-sets:
       -
         name: local-v4
         type: u32
+        byte-order: big-endian
       -
         name: local-v6
         type: binary
@@ -58,6 +59,7 @@ attribute-sets:
       -
         name: peer-v4
         type: u32
+        byte-order: big-endian
       -
         name: peer-v6
         type: binary

net/ipv4/fou_nl.c

@@ -18,9 +18,9 @@ const struct nla_policy fou_nl_policy[FOU_ATTR_IFINDEX + 1] = {
 	[FOU_ATTR_IPPROTO] = NLA_POLICY_MIN(NLA_U8, 1),
 	[FOU_ATTR_TYPE] = { .type = NLA_U8, },
 	[FOU_ATTR_REMCSUM_NOPARTIAL] = { .type = NLA_FLAG, },
-	[FOU_ATTR_LOCAL_V4] = { .type = NLA_U32, },
+	[FOU_ATTR_LOCAL_V4] = { .type = NLA_BE32, },
 	[FOU_ATTR_LOCAL_V6] = NLA_POLICY_EXACT_LEN(16),
-	[FOU_ATTR_PEER_V4] = { .type = NLA_U32, },
+	[FOU_ATTR_PEER_V4] = { .type = NLA_BE32, },
 	[FOU_ATTR_PEER_V6] = NLA_POLICY_EXACT_LEN(16),
 	[FOU_ATTR_PEER_PORT] = { .type = NLA_BE16, },
 	[FOU_ATTR_IFINDEX] = { .type = NLA_S32, },