dict_ext.h

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#pragma once
/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/** Multi-protocol AVP dictionary API
 *
 * @file src/lib/util/dict_ext.h
 *
 * @copyright 2020 The FreeRADIUS server project
 * @copyright 2020,2024 Arran Cudbard-Bell <a.cudbardb@freeradius.org>
 */
RCSIDH(dict_ext_h, "$Id: acf8c1b6485223a54104b39a460a31f65a589bfe $")
 
#include <freeradius-devel/util/dict.h>
#include <freeradius-devel/util/ext.h>
#include <freeradius-devel/util/hash.h>
 
#include <limits.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
extern fr_ext_t const fr_dict_attr_ext_def;
extern fr_ext_t const fr_dict_enum_ext_def;
 
/** Attribute extension - Holds children for an attribute
 *
 * Children are possible for:
 *
 * #FR_TYPE_TLV, #FR_TYPE_VENDOR, #FR_TYPE_VSA, #FR_TYPE_STRUCT
 *
 * *or* where the parent->parent->type is
 * #FR_TYPE_STRUCT, and "parent" is a "key"
 * field.  Note that these attributes therefore
 * cannot have VALUEs, as the child defines their
 * VALUE.  See dict_attr_can_have_children() for details.
 */
typedef struct {
        fr_hash_table_t         *child_by_name;                 //!< Namespace at this level in the hierarchy.
        fr_dict_attr_t const    **children;                     //!< Children of this attribute.
} fr_dict_attr_ext_children_t;
 
DIAG_OFF(attributes)
typedef enum CC_HINT(flag_enum) {
        FR_DICT_ATTR_REF_NONE           = 0x00,                 //!< No ref set.
        FR_DICT_ATTR_REF_ALIAS          = 0x01,                 //!< The attribute is an alias for another attribute.
                                                                ///< Either a straight ALIAS, or a reference into another
                                                                ///< dictionary.
        FR_DICT_ATTR_REF_CLONE          = 0x02,                 //!< The attribute is a "copy" of another attribute.
        FR_DICT_ATTR_REF_ENUM           = 0x04,                 //!< The attribute is an enumeration value.
        FR_DICT_ATTR_REF_KEY            = 0x08,                 //!< it is a UNION which has a ref to a key, and children.
        FR_DICT_ATTR_REF_UNRESOLVED     = 0x10                  //!< This flag is combined with the other states to indicate
                                                                ///< that the reference is unresolved.
} fr_dict_attr_ref_type_t;
DIAG_ON(attributes)
 
#define fr_dict_attr_ref_is_unresolved(_type)   ((_type) & FR_DICT_ATTR_REF_UNRESOLVED)
#define fr_dict_attr_ref_type(_type)            ((_type) & ~FR_DICT_ATTR_REF_UNRESOLVED)
 
/** Attribute extension - Holds a reference to an attribute in another dictionary
 *
 */
typedef struct {
        fr_dict_attr_ref_type_t type;                           //!< The state of the reference.
        union {
                fr_dict_attr_t const    *ref;                   //!< A resolved pointer to the referenced attribute.
                char                    *unresolved;            //!< An unresolved reference (will need resolving later).
        };
} fr_dict_attr_ext_ref_t;
 
/** Attribute extension - Cached vendor pointer
 *
 */
typedef struct {
        fr_dict_attr_t const    *vendor;                        //!< ancestor which has type #FR_TYPE_VENDOR
} fr_dict_attr_ext_vendor_t;
 
/** Attribute extension - Stack of dictionary attributes that describe the path back to the root of the dictionary
 *
 */
typedef struct {
        bool                    unused;                         //!< Zero length arrays are apparently GNU extensions
                                                                ///< and we're not allowed to have structs with a
                                                                ///< single variable array as its member.
                                                                ///< We'll likely want to store something else here
                                                                ///< at some point, so we just have a dummy field to
                                                                ///< avoid changing all the code.
        fr_dict_attr_t const    *da_stack[];                    //!< Stack of dictionary attributes
} fr_dict_attr_ext_da_stack_t;
 
/** Attribute extension - Holds enumeration values
 *
 */
typedef struct {
        size_t                  max_name_len;                   //!< maximum length of a name
        fr_hash_table_t         *value_by_name;                 //!< Lookup an enumeration value by name
        fr_hash_table_t         *name_by_value;                 //!< Lookup a name by value
} fr_dict_attr_ext_enumv_t;
 
/** Attribute extension - Holds a hash table with the names of all children of this attribute
 *
 */
typedef struct {
        fr_hash_table_t         *namespace;                     //!< Lookup a child by name
} fr_dict_attr_ext_namespace_t;
 
/** Enum extension - Sub-struct or union pointer
 *
 */
typedef struct {
        fr_dict_attr_t const    *ref;                           //!< the child structure referenced by this value of key
} fr_dict_enum_ext_key_child_ref_t;
 
/** @name Add extension structures to attributes
 *
 * @{
 */
 
/* Retrieve an extension structure for a dictionary attribute
 *
 * @param[in] da        to retrieve structure from.
 * @param[in] ext       to retrieve.
 * @return
 *      - NULL if the extension wasn't found.
 *      - A pointer to the start of the extension.
 */
static inline void *fr_dict_attr_ext(fr_dict_attr_t const *da, fr_dict_attr_ext_t ext)
{
        if (!da->ext[ext]) return NULL;
 
        return fr_ext_ptr(da, da->ext[ext], fr_dict_attr_ext_def.info[ext].has_hdr);
}
 
/** Return whether a da has a given extension or not
 *
 * @param[in] da        to check for extensions.
 * @param[in] ext       to check.
 * @return
 *      - true if the da has the specified extension.
 *      - false if the da does not have the specified extension
 */
static inline bool fr_dict_attr_has_ext(fr_dict_attr_t const *da, fr_dict_attr_ext_t ext)
{
        return (da->ext[ext] > 0);
}
 
/** Return the cached da stack (if any) associated with an attribute
 *
 * @param[in] da        to return cached da stack for.
 * @return
 *      - NULL if no da stack available.
 *      - The cached da stack on success.
 */
static inline fr_dict_attr_t const **fr_dict_attr_da_stack(fr_dict_attr_t const *da)
{
        fr_dict_attr_ext_da_stack_t *ext;
 
        ext = fr_dict_attr_ext(da, FR_DICT_ATTR_EXT_DA_STACK);
        if (!ext) return NULL;
 
        return ext->da_stack;
}
 
/** Return the reference associated with a group type attribute
 *
 * @param[in] da        to return the reference for.
 * @return
 *      - NULL if no reference available.
 *      - A pointer to the attribute being referenced.
 */
static inline fr_dict_attr_t const *fr_dict_attr_ref(fr_dict_attr_t const *da)
{
        fr_dict_attr_ext_ref_t *ext;
 
        ext = fr_dict_attr_ext(da, FR_DICT_ATTR_EXT_REF);
        if (!ext) return NULL;
 
        /*
         *      Unresolve refs aren't valid refs...
         */
        if (fr_dict_attr_ref_is_unresolved(ext->type)) return NULL;
 
        /*
         *      Temporary backwards compatibility...
         */
        if (ext->type != FR_DICT_ATTR_REF_ALIAS) return NULL;
 
        return ext->ref;
}
 
/** Return the vendor number for an attribute
 *
 * @param[in] da                The dictionary attribute to find the
 *                              vendor for.
 * @return
 *      - 0 this isn't a vendor specific attribute.
 *      - The vendor PEN.
 */
static inline uint32_t fr_dict_vendor_num_by_da(fr_dict_attr_t const *da)
{
        fr_dict_attr_ext_vendor_t *ext;
 
        if (da->type == FR_TYPE_VENDOR) return da->attr;
 
        ext = fr_dict_attr_ext(da, FR_DICT_ATTR_EXT_VENDOR);
        if (!ext || !ext->vendor) return 0;
 
        return ext->vendor->attr;
}
 
/** Return the vendor da for an attribute
 *
 * @param[in] da                The dictionary attribute to find the
 *                              vendor for.
 * @return
 *      - 0 this isn't a vendor specific attribute.
 *      - The vendor PEN.
 */
static inline fr_dict_attr_t const *fr_dict_vendor_da_by_da(fr_dict_attr_t const *da)
{
        fr_dict_attr_ext_vendor_t *ext;
 
        if (da->type == FR_TYPE_VENDOR) return da;
 
        ext = fr_dict_attr_ext(da, FR_DICT_ATTR_EXT_VENDOR);
        if (!ext) return NULL;
 
        return ext->vendor;
}
 
/** @} */
 
void fr_dict_attr_ext_debug(fr_dict_attr_t const *da);
 
#ifdef __cplusplus
}
#endif