/*
 * Copyright (c) 2017, Mellanox Technologies inc.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef _UVERBS_IOCTL_
#define _UVERBS_IOCTL_

#include <rdma/uverbs_types.h>
#include <linux/uaccess.h>
#include <rdma/rdma_user_ioctl.h>
#include <rdma/ib_user_ioctl_verbs.h>
#include <rdma/ib_user_ioctl_cmds.h>

/*
 * =======================================
 *      Verbs action specifications
 * =======================================
 */

enum uverbs_attr_type {
        UVERBS_ATTR_TYPE_NA,
        UVERBS_ATTR_TYPE_PTR_IN,
        UVERBS_ATTR_TYPE_PTR_OUT,
        UVERBS_ATTR_TYPE_IDR,
        UVERBS_ATTR_TYPE_FD,
        UVERBS_ATTR_TYPE_ENUM_IN,
};

enum uverbs_obj_access {
        UVERBS_ACCESS_READ,
        UVERBS_ACCESS_WRITE,
        UVERBS_ACCESS_NEW,
        UVERBS_ACCESS_DESTROY
};

enum {
        UVERBS_ATTR_SPEC_F_MANDATORY    = 1U << 0,
        /* Support extending attributes by length, validate all unknown size == zero  */
        UVERBS_ATTR_SPEC_F_MIN_SZ_OR_ZERO = 1U << 1,
};

/* Specification of a single attribute inside the ioctl message */
struct uverbs_attr_spec {
        union {
                /* Header shared by all following union members - to reduce space. */
                struct {
                        enum uverbs_attr_type           type;
                        /* Combination of bits from enum UVERBS_ATTR_SPEC_F_XXXX */
                        u8                              flags;
                };
                struct {
                        enum uverbs_attr_type           type;
                        /* Combination of bits from enum UVERBS_ATTR_SPEC_F_XXXX */
                        u8                              flags;
                        /* Current known size to kernel */
                        u16                             len;
                        /* User isn't allowed to provide something < min_len */
                        u16                             min_len;
                } ptr;
                struct {
                        enum uverbs_attr_type           type;
                        /* Combination of bits from enum UVERBS_ATTR_SPEC_F_XXXX */
                        u8                              flags;
                        /*
                         * higher bits mean the namespace and lower bits mean
                         * the type id within the namespace.
                         */
                        u16                     obj_type;
                        u8                      access;
                } obj;
                struct {
                        enum uverbs_attr_type           type;
                        /* Combination of bits from enum UVERBS_ATTR_SPEC_F_XXXX */
                        u8                              flags;
                        u8                              num_elems;
                        /*
                         * The enum attribute can select one of the attributes
                         * contained in the ids array. Currently only PTR_IN
                         * attributes are supported in the ids array.
                         */
                        const struct uverbs_attr_spec   *ids;
                } enum_def;
        };
};

struct uverbs_attr_spec_hash {
        size_t                          num_attrs;
        unsigned long                   *mandatory_attrs_bitmask;
        struct uverbs_attr_spec         attrs[0];
};

struct uverbs_attr_bundle;
struct ib_uverbs_file;

enum {
        /*
         * Action marked with this flag creates a context (or root for all
         * objects).
         */
        UVERBS_ACTION_FLAG_CREATE_ROOT = 1U << 0,
};

struct uverbs_method_spec {
        /* Combination of bits from enum UVERBS_ACTION_FLAG_XXXX */
        u32                                             flags;
        size_t                                          num_buckets;
        size_t                                          num_child_attrs;
        int (*handler)(struct ib_device *ib_dev, struct ib_uverbs_file *ufile,
                       struct uverbs_attr_bundle *ctx);
        struct uverbs_attr_spec_hash            *attr_buckets[0];
};

struct uverbs_method_spec_hash {
        size_t                                  num_methods;
        struct uverbs_method_spec               *methods[0];
};

struct uverbs_object_spec {
        const struct uverbs_obj_type            *type_attrs;
        size_t                                  num_buckets;
        struct uverbs_method_spec_hash          *method_buckets[0];
};

struct uverbs_object_spec_hash {
        size_t                                  num_objects;
        struct uverbs_object_spec               *objects[0];
};

struct uverbs_root_spec {
        size_t                                  num_buckets;
        struct uverbs_object_spec_hash          *object_buckets[0];
};

/*
 * =======================================
 *      Verbs definitions
 * =======================================
 */

struct uverbs_attr_def {
        u16                           id;
        struct uverbs_attr_spec       attr;
};

struct uverbs_method_def {
        u16                                  id;
        /* Combination of bits from enum UVERBS_ACTION_FLAG_XXXX */
        u32                                  flags;
        size_t                               num_attrs;
        const struct uverbs_attr_def * const (*attrs)[];
        int (*handler)(struct ib_device *ib_dev, struct ib_uverbs_file *ufile,
                       struct uverbs_attr_bundle *ctx);
};

struct uverbs_object_def {
        u16                                      id;
        const struct uverbs_obj_type            *type_attrs;
        size_t                                   num_methods;
        const struct uverbs_method_def * const (*methods)[];
};

struct uverbs_object_tree_def {
        size_t                                   num_objects;
        const struct uverbs_object_def * const (*objects)[];
};

#define UA_FLAGS(_flags)  .flags = _flags
#define __UVERBS_ATTR0(_id, _type, _fld, _attr, ...)              \
        ((const struct uverbs_attr_def)                           \
         {.id = _id, .attr = {{._fld = {.type = _type, _attr, .flags = 0, } }, } })
#define __UVERBS_ATTR1(_id, _type, _fld, _attr, _extra1, ...)      \
        ((const struct uverbs_attr_def)                           \
         {.id = _id, .attr = {{._fld = {.type = _type, _attr, _extra1 } },} })
#define __UVERBS_ATTR2(_id, _type, _fld, _attr, _extra1, _extra2)    \
        ((const struct uverbs_attr_def)                           \
         {.id = _id, .attr = {{._fld = {.type = _type, _attr, _extra1, _extra2 } },} })
#define __UVERBS_ATTR(_id, _type, _fld, _attr, _extra1, _extra2, _n, ...)       \
        __UVERBS_ATTR##_n(_id, _type, _fld, _attr, _extra1, _extra2)

#define UVERBS_ATTR_TYPE(_type)                                 \
        .min_len = sizeof(_type), .len = sizeof(_type)
#define UVERBS_ATTR_STRUCT(_type, _last)                        \
        .min_len = ((uintptr_t)(&((_type *)0)->_last + 1)), .len = sizeof(_type)
#define UVERBS_ATTR_SIZE(_min_len, _len)                        \
        .min_len = _min_len, .len = _len

/*
 * In new compiler, UVERBS_ATTR could be simplified by declaring it as
 * [_id] = {.type = _type, .len = _len, ##__VA_ARGS__}
 * But since we support older compilers too, we need the more complex code.
 */
#define UVERBS_ATTR(_id, _type, _fld, _attr, ...)                       \
        __UVERBS_ATTR(_id, _type, _fld, _attr, ##__VA_ARGS__, 2, 1, 0)
#define UVERBS_ATTR_PTR_IN_SZ(_id, _len, ...)                           \
        UVERBS_ATTR(_id, UVERBS_ATTR_TYPE_PTR_IN, ptr, _len, ##__VA_ARGS__)
/* If sizeof(_type) <= sizeof(u64), this will be inlined rather than a pointer */
#define UVERBS_ATTR_PTR_IN(_id, _type, ...)                             \
        UVERBS_ATTR_PTR_IN_SZ(_id, _type, ##__VA_ARGS__)
#define UVERBS_ATTR_PTR_OUT_SZ(_id, _len, ...)                          \
        UVERBS_ATTR(_id, UVERBS_ATTR_TYPE_PTR_OUT, ptr, _len, ##__VA_ARGS__)
#define UVERBS_ATTR_PTR_OUT(_id, _type, ...)                            \
        UVERBS_ATTR_PTR_OUT_SZ(_id, _type, ##__VA_ARGS__)
#define UVERBS_ATTR_ENUM_IN(_id, _enum_arr, ...)                        \
        UVERBS_ATTR(_id, UVERBS_ATTR_TYPE_ENUM_IN, enum_def,            \
                    .ids = (_enum_arr),                                 \
                    .num_elems = ARRAY_SIZE(_enum_arr), ##__VA_ARGS__)

/*
 * In new compiler, UVERBS_ATTR_IDR (and FD) could be simplified by declaring
 * it as
 * {.id = _id,                                                          \
 *  .attr {.type = __obj_class,                                         \
 *         .obj = {.obj_type = _idr_type,                               \
 *                       .access = _access                              \
 *                }, ##__VA_ARGS__ } }
 * But since we support older compilers too, we need the more complex code.
 */
#define ___UVERBS_ATTR_OBJ0(_id, _obj_class, _obj_type, _access, ...)\
        ((const struct uverbs_attr_def)                                 \
        {.id = _id,                                                     \
         .attr = { {.obj = {.type = _obj_class, .obj_type = _obj_type,  \
                            .access = _access, .flags = 0 } }, } })
#define ___UVERBS_ATTR_OBJ1(_id, _obj_class, _obj_type, _access, _flags)\
        ((const struct uverbs_attr_def)                                 \
        {.id = _id,                                                     \
        .attr = { {.obj = {.type = _obj_class, .obj_type = _obj_type,   \
                           .access = _access, _flags} }, } })
#define ___UVERBS_ATTR_OBJ(_id, _obj_class, _obj_type, _access, _flags, \
                           _n, ...)                                     \
        ___UVERBS_ATTR_OBJ##_n(_id, _obj_class, _obj_type, _access, _flags)
#define __UVERBS_ATTR_OBJ(_id, _obj_class, _obj_type, _access, ...)     \
        ___UVERBS_ATTR_OBJ(_id, _obj_class, _obj_type, _access,         \
                           ##__VA_ARGS__, 1, 0)
#define UVERBS_ATTR_IDR(_id, _idr_type, _access, ...)                    \
        __UVERBS_ATTR_OBJ(_id, UVERBS_ATTR_TYPE_IDR, _idr_type, _access,\
                          ##__VA_ARGS__)
#define UVERBS_ATTR_FD(_id, _fd_type, _access, ...)                     \
        __UVERBS_ATTR_OBJ(_id, UVERBS_ATTR_TYPE_FD, _fd_type,           \
                          (_access) + BUILD_BUG_ON_ZERO(                \
                                (_access) != UVERBS_ACCESS_NEW &&       \
                                (_access) != UVERBS_ACCESS_READ),       \
                          ##__VA_ARGS__)
#define DECLARE_UVERBS_ATTR_SPEC(_name, ...)                            \
        const struct uverbs_attr_def _name = __VA_ARGS__

#define DECLARE_UVERBS_ENUM(_name, ...)                                 \
        const struct uverbs_enum_spec _name = {                         \
                .len = ARRAY_SIZE(((struct uverbs_attr_spec[]){__VA_ARGS__})),\
                .ids = {__VA_ARGS__},                                   \
        }
#define _UVERBS_METHOD_ATTRS_SZ(...)                                    \
        (sizeof((const struct uverbs_attr_def * const []){__VA_ARGS__}) /\
         sizeof(const struct uverbs_attr_def *))
#define _UVERBS_METHOD(_id, _handler, _flags, ...)                      \
        ((const struct uverbs_method_def) {                             \
         .id = _id,                                                     \
         .flags = _flags,                                               \
         .handler = _handler,                                           \
         .num_attrs = _UVERBS_METHOD_ATTRS_SZ(__VA_ARGS__),             \
         .attrs = &(const struct uverbs_attr_def * const []){__VA_ARGS__} })
#define DECLARE_UVERBS_METHOD(_name, _id, _handler, ...)                \
        const struct uverbs_method_def _name =                          \
                _UVERBS_METHOD(_id, _handler, 0, ##__VA_ARGS__)
#define DECLARE_UVERBS_CTX_METHOD(_name, _id, _handler, _flags, ...)    \
        const struct uverbs_method_def _name =                          \
                _UVERBS_METHOD(_id, _handler,                           \
                               UVERBS_ACTION_FLAG_CREATE_ROOT,          \
                               ##__VA_ARGS__)
#define _UVERBS_OBJECT_METHODS_SZ(...)                                  \
        (sizeof((const struct uverbs_method_def * const []){__VA_ARGS__}) / \
         sizeof(const struct uverbs_method_def *))
#define _UVERBS_OBJECT(_id, _type_attrs, ...)                           \
        ((const struct uverbs_object_def) {                             \
         .id = _id,                                                     \
         .type_attrs = _type_attrs,                                     \
         .num_methods = _UVERBS_OBJECT_METHODS_SZ(__VA_ARGS__),         \
         .methods = &(const struct uverbs_method_def * const []){__VA_ARGS__} })
#define DECLARE_UVERBS_OBJECT(_name, _id, _type_attrs, ...)             \
        const struct uverbs_object_def _name =                          \
                _UVERBS_OBJECT(_id, _type_attrs, ##__VA_ARGS__)
#define _UVERBS_TREE_OBJECTS_SZ(...)                                    \
        (sizeof((const struct uverbs_object_def * const []){__VA_ARGS__}) / \
         sizeof(const struct uverbs_object_def *))
#define _UVERBS_OBJECT_TREE(...)                                        \
        ((const struct uverbs_object_tree_def) {                        \
         .num_objects = _UVERBS_TREE_OBJECTS_SZ(__VA_ARGS__),           \
         .objects = &(const struct uverbs_object_def * const []){__VA_ARGS__} })
#define DECLARE_UVERBS_OBJECT_TREE(_name, ...)                          \
        const struct uverbs_object_tree_def _name =                     \
                _UVERBS_OBJECT_TREE(__VA_ARGS__)

/* =================================================
 *              Parsing infrastructure
 * =================================================
 */

struct uverbs_ptr_attr {
        u64             data;
        u16             len;
        /* Combination of bits from enum UVERBS_ATTR_F_XXXX */
        u16             flags;
        u8              enum_id;
};

struct uverbs_obj_attr {
        /* pointer to the kernel descriptor -> type, access, etc */
        const struct uverbs_obj_type    *type;
        struct ib_uobject               *uobject;
        /* fd or id in idr of this object */
        int                             id;
};

struct uverbs_attr {
        /*
         * pointer to the user-space given attribute, in order to write the
         * new uobject's id or update flags.
         */
        struct ib_uverbs_attr __user    *uattr;
        union {
                struct uverbs_ptr_attr  ptr_attr;
                struct uverbs_obj_attr  obj_attr;
        };
};

struct uverbs_attr_bundle_hash {
        /* if bit i is set, it means attrs[i] contains valid information */
        unsigned long *valid_bitmap;
        size_t num_attrs;
        /*
         * arrays of attributes, each element corresponds to the specification
         * of the attribute in the same index.
         */
        struct uverbs_attr *attrs;
};

struct uverbs_attr_bundle {
        size_t                          num_buckets;
        struct uverbs_attr_bundle_hash  hash[];
};

static inline bool uverbs_attr_is_valid_in_hash(const struct uverbs_attr_bundle_hash *attrs_hash,
                                                unsigned int idx)
{
        return test_bit(idx, attrs_hash->valid_bitmap);
}

static inline bool uverbs_attr_is_valid(const struct uverbs_attr_bundle *attrs_bundle,
                                        unsigned int idx)
{
        u16 idx_bucket = idx >> UVERBS_ID_NS_SHIFT;

        if (attrs_bundle->num_buckets <= idx_bucket)
                return false;

        return uverbs_attr_is_valid_in_hash(&attrs_bundle->hash[idx_bucket],
                                            idx & ~UVERBS_ID_NS_MASK);
}

#define IS_UVERBS_COPY_ERR(_ret)                ((_ret) && (_ret) != -ENOENT)

static inline const struct uverbs_attr *uverbs_attr_get(const struct uverbs_attr_bundle *attrs_bundle,
                                                        u16 idx)
{
        u16 idx_bucket = idx >> UVERBS_ID_NS_SHIFT;

        if (!uverbs_attr_is_valid(attrs_bundle, idx))
                return ERR_PTR(-ENOENT);

        return &attrs_bundle->hash[idx_bucket].attrs[idx & ~UVERBS_ID_NS_MASK];
}

static inline int uverbs_attr_get_enum_id(const struct uverbs_attr_bundle *attrs_bundle,
                                          u16 idx)
{
        const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);

        if (IS_ERR(attr))
                return PTR_ERR(attr);

        return attr->ptr_attr.enum_id;
}

static inline void *uverbs_attr_get_obj(const struct uverbs_attr_bundle *attrs_bundle,
                                        u16 idx)
{
        const struct uverbs_attr *attr;

        attr = uverbs_attr_get(attrs_bundle, idx);
        if (IS_ERR(attr))
                return ERR_CAST(attr);

        return attr->obj_attr.uobject->object;
}

static inline struct ib_uobject *uverbs_attr_get_uobject(const struct uverbs_attr_bundle *attrs_bundle,
                                                         u16 idx)
{
        const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);

        if (IS_ERR(attr))
                return ERR_CAST(attr);

        return attr->obj_attr.uobject;
}

static inline int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle,
                                 size_t idx, const void *from, size_t size)
{
        const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
        u16 flags;
        size_t min_size;

        if (IS_ERR(attr))
                return PTR_ERR(attr);

        min_size = min_t(size_t, attr->ptr_attr.len, size);
        if (copy_to_user(u64_to_user_ptr(attr->ptr_attr.data), from, min_size))
                return -EFAULT;

        flags = attr->ptr_attr.flags | UVERBS_ATTR_F_VALID_OUTPUT;
        if (put_user(flags, &attr->uattr->flags))
                return -EFAULT;

        return 0;
}

static inline bool uverbs_attr_ptr_is_inline(const struct uverbs_attr *attr)
{
        return attr->ptr_attr.len <= sizeof(attr->ptr_attr.data);
}

static inline int _uverbs_copy_from(void *to,
                                    const struct uverbs_attr_bundle *attrs_bundle,
                                    size_t idx,
                                    size_t size)
{
        const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);

        if (IS_ERR(attr))
                return PTR_ERR(attr);

        /*
         * Validation ensures attr->ptr_attr.len >= size. If the caller is
         * using UVERBS_ATTR_SPEC_F_MIN_SZ_OR_ZERO then it must call
         * uverbs_copy_from_or_zero.
         */
        if (unlikely(size < attr->ptr_attr.len))
                return -EINVAL;

        if (uverbs_attr_ptr_is_inline(attr))
                memcpy(to, &attr->ptr_attr.data, attr->ptr_attr.len);
        else if (copy_from_user(to, u64_to_user_ptr(attr->ptr_attr.data),
                                attr->ptr_attr.len))
                return -EFAULT;

        return 0;
}

static inline int _uverbs_copy_from_or_zero(void *to,
                                            const struct uverbs_attr_bundle *attrs_bundle,
                                            size_t idx,
                                            size_t size)
{
        const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
        size_t min_size;

        if (IS_ERR(attr))
                return PTR_ERR(attr);

        min_size = min_t(size_t, size, attr->ptr_attr.len);

        if (uverbs_attr_ptr_is_inline(attr))
                memcpy(to, &attr->ptr_attr.data, min_size);
        else if (copy_from_user(to, u64_to_user_ptr(attr->ptr_attr.data),
                                min_size))
                return -EFAULT;

        if (size > min_size)
                memset(to + min_size, 0, size - min_size);

        return 0;
}

#define uverbs_copy_from(to, attrs_bundle, idx)                               \
        _uverbs_copy_from(to, attrs_bundle, idx, sizeof(*to))

#define uverbs_copy_from_or_zero(to, attrs_bundle, idx)                       \
        _uverbs_copy_from_or_zero(to, attrs_bundle, idx, sizeof(*to))

/* =================================================
 *       Definitions -> Specs infrastructure
 * =================================================
 */

/*
 * uverbs_alloc_spec_tree - Merges different common and driver specific feature
 *      into one parsing tree that every uverbs command will be parsed upon.
 *
 * @num_trees: Number of trees in the array @trees.
 * @trees: Array of pointers to tree root definitions to merge. Each such tree
 *         possibly contains objects, methods and attributes definitions.
 *
 * Returns:
 *      uverbs_root_spec *: The root of the merged parsing tree.
 *      On error, we return an error code. Error is checked via IS_ERR.
 *
 * The following merges could take place:
 * a. Two trees representing the same method with different handler
 *      -> We take the handler of the tree that its handler != NULL
 *         and its index in the trees array is greater. The incentive for that
 *         is that developers are expected to first merge common trees and then
 *         merge trees that gives specialized the behaviour.
 * b. Two trees representing the same object with different
 *    type_attrs (struct uverbs_obj_type):
 *      -> We take the type_attrs of the tree that its type_attr != NULL
 *         and its index in the trees array is greater. This could be used
 *         in order to override the free function, allocation size, etc.
 * c. Two trees representing the same method attribute (same id but possibly
 *    different attributes):
 *      -> ERROR (-ENOENT), we believe that's not the programmer's intent.
 *
 * An object without any methods is considered invalid and will abort the
 * function with -ENOENT error.
 */
#if IS_ENABLED(CONFIG_INFINIBAND_USER_ACCESS)
struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
                                                const struct uverbs_object_tree_def **trees);
void uverbs_free_spec_tree(struct uverbs_root_spec *root);
#else
static inline struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
                                                              const struct uverbs_object_tree_def **trees)
{
        return NULL;
}

static inline void uverbs_free_spec_tree(struct uverbs_root_spec *root)
{
}
#endif

#endif