diff options
Diffstat (limited to 'include/linux/genl_magic_struct.h')
| -rw-r--r-- | include/linux/genl_magic_struct.h | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/include/linux/genl_magic_struct.h b/include/linux/genl_magic_struct.h new file mode 100644 index 000000000000..745ebfd6c7e5 --- /dev/null +++ b/include/linux/genl_magic_struct.h @@ -0,0 +1,260 @@ +#ifndef GENL_MAGIC_STRUCT_H +#define GENL_MAGIC_STRUCT_H + +#ifndef GENL_MAGIC_FAMILY +# error "you need to define GENL_MAGIC_FAMILY before inclusion" +#endif + +#ifndef GENL_MAGIC_VERSION +# error "you need to define GENL_MAGIC_VERSION before inclusion" +#endif + +#ifndef GENL_MAGIC_INCLUDE_FILE +# error "you need to define GENL_MAGIC_INCLUDE_FILE before inclusion" +#endif + +#include <linux/genetlink.h> +#include <linux/types.h> + +#define CONCAT__(a,b) a ## b +#define CONCAT_(a,b) CONCAT__(a,b) + +extern int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void); +extern void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void); + +/* + * Extension of genl attribute validation policies {{{2 + */ + +/** + * GENLA_F_FLAGS - policy type flags to ease compatible ABI evolvement + * + * @GENLA_F_REQUIRED: attribute has to be present, or message is considered invalid. + * Adding new REQUIRED attributes breaks ABI compatibility, so don't do that. + * + * @GENLA_F_MANDATORY: if present, receiver _must_ understand it. + * Without this, unknown attributes (> maxtype) are _silently_ ignored + * by validate_nla(). + * + * To be used for API extensions, so older kernel can reject requests for not + * yet implemented features, if newer userland tries to use them even though + * the genl_family version clearly indicates they are not available. + * + * @GENLA_F_MAY_IGNORE: To clearly document the fact, for good measure. + * To be used for API extensions for things that have sane defaults, + * so newer userland can still talk to older kernel, knowing it will + * silently ignore these attributes if not yet known. + * + * NOTE: These flags overload + * NLA_F_NESTED (1 << 15) + * NLA_F_NET_BYTEORDER (1 << 14) + * from linux/netlink.h, which are not useful for validate_nla(): + * NET_BYTEORDER is not used anywhere, and NESTED would be specified by setting + * .type = NLA_NESTED in the appropriate policy. + * + * See also: nla_type() + */ +enum { + GENLA_F_MAY_IGNORE = 0, + GENLA_F_MANDATORY = 1 << 14, + GENLA_F_REQUIRED = 1 << 15, + + /* This will not be present in the __u16 .nla_type, but can be + * triggered on in <struct>_to_skb, to exclude "sensitive" + * information from broadcasts, or on unpriviledged get requests. + * This is useful because genetlink multicast groups can be listened in + * on by anyone. */ + GENLA_F_SENSITIVE = 1 << 16, +}; + +#define __nla_type(x) ((__u16)((__u16)(x) & (__u16)NLA_TYPE_MASK)) + +/* }}}1 + * MAGIC + * multi-include macro expansion magic starts here + */ + +/* MAGIC helpers {{{2 */ + +/* possible field types */ +#define __flg_field(attr_nr, attr_flag, name) \ + __field(attr_nr, attr_flag, name, NLA_FLAG, char, \ + nla_get_flag, __nla_put_flag) +#define __u8_field(attr_nr, attr_flag, name) \ + __field(attr_nr, attr_flag, name, NLA_U8, unsigned char, \ + nla_get_u8, NLA_PUT_U8) +#define __u16_field(attr_nr, attr_flag, name) \ + __field(attr_nr, attr_flag, name, NLA_U16, __u16, \ + nla_get_u16, NLA_PUT_U16) +#define __u32_field(attr_nr, attr_flag, name) \ + __field(attr_nr, attr_flag, name, NLA_U32, __u32, \ + nla_get_u32, NLA_PUT_U32) +#define __u64_field(attr_nr, attr_flag, name) \ + __field(attr_nr, attr_flag, name, NLA_U64, __u64, \ + nla_get_u64, NLA_PUT_U64) +#define __str_field(attr_nr, attr_flag, name, maxlen) \ + __array(attr_nr, attr_flag, name, NLA_NUL_STRING, char, maxlen, \ + nla_strlcpy, NLA_PUT) +#define __bin_field(attr_nr, attr_flag, name, maxlen) \ + __array(attr_nr, attr_flag, name, NLA_BINARY, char, maxlen, \ + nla_memcpy, NLA_PUT) + +#define __nla_put_flag(skb, attrtype, value) \ + do { \ + if (value) \ + NLA_PUT_FLAG(skb, attrtype); \ + } while (0) + +#define GENL_op_init(args...) args +#define GENL_doit(handler) \ + .doit = handler, \ + .flags = GENL_ADMIN_PERM, +#define GENL_dumpit(handler) \ + .dumpit = handler, \ + .flags = GENL_ADMIN_PERM, + +/* }}}1 + * Magic: define the enum symbols for genl_ops + * Magic: define the enum symbols for top level attributes + * Magic: define the enum symbols for nested attributes + * {{{2 + */ + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) + +#undef GENL_mc_group +#define GENL_mc_group(group) + +#undef GENL_notification +#define GENL_notification(op_name, op_num, mcast_group, tla_list) \ + op_name = op_num, + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, tla_list) \ + op_name = op_num, + +enum { +#include GENL_MAGIC_INCLUDE_FILE +}; + +#undef GENL_notification +#define GENL_notification(op_name, op_num, mcast_group, tla_list) + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, attr_list) + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ + tag_name = tag_number, + +enum { +#include GENL_MAGIC_INCLUDE_FILE +}; + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ +enum { \ + s_fields \ +}; + +#undef __field +#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \ + T_ ## name = (__u16)(attr_nr | attr_flag), + +#undef __array +#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \ + T_ ## name = (__u16)(attr_nr | attr_flag), + +#include GENL_MAGIC_INCLUDE_FILE + +/* }}}1 + * Magic: compile time assert unique numbers for operations + * Magic: -"- unique numbers for top level attributes + * Magic: -"- unique numbers for nested attributes + * {{{2 + */ + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, attr_list) \ + case op_name: + +#undef GENL_notification +#define GENL_notification(op_name, op_num, mcast_group, tla_list) \ + case op_name: + +static inline void ct_assert_unique_operations(void) +{ + switch (0) { +#include GENL_MAGIC_INCLUDE_FILE + ; + } +} + +#undef GENL_op +#define GENL_op(op_name, op_num, handler, attr_list) + +#undef GENL_notification +#define GENL_notification(op_name, op_num, mcast_group, tla_list) + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ + case tag_number: + +static inline void ct_assert_unique_top_level_attributes(void) +{ + switch (0) { +#include GENL_MAGIC_INCLUDE_FILE + ; + } +} + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ +static inline void ct_assert_unique_ ## s_name ## _attributes(void) \ +{ \ + switch (0) { \ + s_fields \ + ; \ + } \ +} + +#undef __field +#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \ + case attr_nr: + +#undef __array +#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \ + case attr_nr: + +#include GENL_MAGIC_INCLUDE_FILE + +/* }}}1 + * Magic: declare structs + * struct <name> { + * fields + * }; + * {{{2 + */ + +#undef GENL_struct +#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ +struct s_name { s_fields }; + +#undef __field +#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \ + type name; + +#undef __array +#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \ + type name[maxlen]; \ + __u32 name ## _len; + +#include GENL_MAGIC_INCLUDE_FILE + +/* }}}1 */ +#endif /* GENL_MAGIC_STRUCT_H */ +/* vim: set foldmethod=marker nofoldenable : */ |