Merge branch 'ethtool-allow-dumping-policies-to-user-space'

Jakub Kicinski says:

====================
ethtool: allow dumping policies to user space

This series wires up ethtool policies to ops, so they can be
dumped to user space for feature discovery.

First patch wires up GET commands, and second patch wires up SETs.

The policy tables are trimmed to save space and LoC.

Next - take care of linking up nested policies for the header
(which is the policy what we actually care about). And once header
policy is linked make sure that attribute range validation for flags
is done by policy, not a conditions in the code. New type of policy
is needed to validate masks (patch 6).

Netlink as always staying a step ahead of all the other kernel
API interfaces :)

v2:
 - merge patches 1 & 2 -> 1
 - add patch 3 & 5
 - remove .max_attr from struct ethnl_request_ops
====================

Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 21 insertions, 8 deletions

diff --git a/include/net/netlink.h b/include/net/netlink.h
index 5a5ff97cc596..2b9e41075f19 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -200,6 +200,7 @@ enum nla_policy_validation {
 	NLA_VALIDATE_RANGE_WARN_TOO_LONG,
 	NLA_VALIDATE_MIN,
 	NLA_VALIDATE_MAX,
+	NLA_VALIDATE_MASK,
 	NLA_VALIDATE_RANGE_PTR,
 	NLA_VALIDATE_FUNCTION,
 };
@@ -317,6 +318,7 @@ struct nla_policy {
 	u16		len;
 	union {
 		const u32 bitfield32_valid;
+		const u32 mask;
 		const char *reject_message;
 		const struct nla_policy *nested_policy;
 		struct netlink_range_validation *range;
@@ -362,20 +364,23 @@ struct nla_policy {
 #define NLA_POLICY_BITFIELD32(valid) \
 	{ .type = NLA_BITFIELD32, .bitfield32_valid = valid }
 
+#define __NLA_IS_UINT_TYPE(tp)						\
+	(tp == NLA_U8 || tp == NLA_U16 || tp == NLA_U32 || tp == NLA_U64)
+#define __NLA_IS_SINT_TYPE(tp)						\
+	(tp == NLA_S8 || tp == NLA_S16 || tp == NLA_S32 || tp == NLA_S64)
+
 #define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition))
+#define NLA_ENSURE_UINT_TYPE(tp)			\
+	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp)) + tp)
 #define NLA_ENSURE_UINT_OR_BINARY_TYPE(tp)		\
-	(__NLA_ENSURE(tp == NLA_U8 || tp == NLA_U16 ||	\
-		      tp == NLA_U32 || tp == NLA_U64 ||	\
+	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) ||	\
 		      tp == NLA_MSECS ||		\
 		      tp == NLA_BINARY) + tp)
 #define NLA_ENSURE_SINT_TYPE(tp)			\
-	(__NLA_ENSURE(tp == NLA_S8 || tp == NLA_S16  ||	\
-		      tp == NLA_S32 || tp == NLA_S64) + tp)
+	(__NLA_ENSURE(__NLA_IS_SINT_TYPE(tp)) + tp)
 #define NLA_ENSURE_INT_OR_BINARY_TYPE(tp)		\
-	(__NLA_ENSURE(tp == NLA_S8 || tp == NLA_U8 ||	\
-		      tp == NLA_S16 || tp == NLA_U16 ||	\
-		      tp == NLA_S32 || tp == NLA_U32 ||	\
-		      tp == NLA_S64 || tp == NLA_U64 ||	\
+	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) ||		\
+		      __NLA_IS_SINT_TYPE(tp) ||		\
 		      tp == NLA_MSECS ||		\
 		      tp == NLA_BINARY) + tp)
 #define NLA_ENSURE_NO_VALIDATION_PTR(tp)		\
@@ -415,6 +420,12 @@ struct nla_policy {
 	.max = _max,					\
 }
 
+#define NLA_POLICY_MASK(tp, _mask) {			\
+	.type = NLA_ENSURE_UINT_TYPE(tp),		\
+	.validation_type = NLA_VALIDATE_MASK,		\
+	.mask = _mask,					\
+}
+
 #define NLA_POLICY_VALIDATE_FN(tp, fn, ...) {		\
 	.type = NLA_ENSURE_NO_VALIDATION_PTR(tp),	\
 	.validation_type = NLA_VALIDATE_FUNCTION,	\
diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h
index eac8a6a648ea..d02e472ba54c 100644
--- a/include/uapi/linux/netlink.h
+++ b/include/uapi/linux/netlink.h
@@ -331,6 +331,7 @@ enum netlink_attribute_type {
  *	the index, if limited inside the nesting (U32)
  * @NL_POLICY_TYPE_ATTR_BITFIELD32_MASK: valid mask for the
  *	bitfield32 type (U32)
+ * @NL_POLICY_TYPE_ATTR_MASK: mask of valid bits for unsigned integers (U64)
  * @NL_POLICY_TYPE_ATTR_PAD: pad attribute for 64-bit alignment
  */
 enum netlink_policy_type_attr {
@@ -346,6 +347,7 @@ enum netlink_policy_type_attr {
 	NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE,
 	NL_POLICY_TYPE_ATTR_BITFIELD32_MASK,
 	NL_POLICY_TYPE_ATTR_PAD,
+	NL_POLICY_TYPE_ATTR_MASK,
 
 	/* keep last */
 	__NL_POLICY_TYPE_ATTR_MAX,