netlink: clarify attribute length check documentation
The documentation for how the length of attributes
is checked is wrong ("Exact length" isn't true, the
policy checks are for "minimum length") and a bit
misleading. Make it more complete and explain what
really happens.
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 98c1854..cb1f350 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -192,8 +192,15 @@
* NLA_NUL_STRING Maximum length of string (excluding NUL)
* NLA_FLAG Unused
* NLA_BINARY Maximum length of attribute payload
- * NLA_NESTED_COMPAT Exact length of structure payload
- * All other Exact length of attribute payload
+ * NLA_NESTED Don't use `len' field -- length verification is
+ * done by checking len of nested header (or empty)
+ * NLA_NESTED_COMPAT Minimum length of structure payload
+ * NLA_U8, NLA_U16,
+ * NLA_U32, NLA_U64,
+ * NLA_MSECS Leaving the length field zero will verify the
+ * given type fits, using it verifies minimum length
+ * just like "All other"
+ * All other Minimum length of attribute payload
*
* Example:
* static const struct nla_policy my_policy[ATTR_MAX+1] = {