/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright 2019 Google LLC
 */

#ifndef __LINUX_BLK_CRYPTO_INTERNAL_H
#define __LINUX_BLK_CRYPTO_INTERNAL_H

#include <linux/bio.h>
#include <linux/blkdev.h>

/* Represents a crypto mode supported by blk-crypto  */
struct blk_crypto_mode {
        const char *cipher_str; /* crypto API name (for fallback case) */
        unsigned int keysize; /* key size in bytes */
        unsigned int ivsize; /* iv size in bytes */
};

extern const struct blk_crypto_mode blk_crypto_modes[];

#ifdef CONFIG_BLK_INLINE_ENCRYPTION

void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
                             unsigned int inc);

bool bio_crypt_rq_ctx_compatible(struct request *rq, struct bio *bio);

bool bio_crypt_ctx_mergeable(struct bio_crypt_ctx *bc1, unsigned int bc1_bytes,
                             struct bio_crypt_ctx *bc2);

static inline bool bio_crypt_ctx_back_mergeable(struct request *req,
                                                struct bio *bio)
{
        return bio_crypt_ctx_mergeable(req->crypt_ctx, blk_rq_bytes(req),
                                       bio->bi_crypt_context);
}

static inline bool bio_crypt_ctx_front_mergeable(struct request *req,
                                                 struct bio *bio)
{
        return bio_crypt_ctx_mergeable(bio->bi_crypt_context,
                                       bio->bi_iter.bi_size, req->crypt_ctx);
}

static inline bool bio_crypt_ctx_merge_rq(struct request *req,
                                          struct request *next)
{
        return bio_crypt_ctx_mergeable(req->crypt_ctx, blk_rq_bytes(req),
                                       next->crypt_ctx);
}

static inline void blk_crypto_rq_set_defaults(struct request *rq)
{
        rq->crypt_ctx = NULL;
        rq->crypt_keyslot = NULL;
}

static inline bool blk_crypto_rq_is_encrypted(struct request *rq)
{
        return rq->crypt_ctx;
}

#else /* CONFIG_BLK_INLINE_ENCRYPTION */

static inline bool bio_crypt_rq_ctx_compatible(struct request *rq,
                                               struct bio *bio)
{
        return true;
}

static inline bool bio_crypt_ctx_front_mergeable(struct request *req,
                                                 struct bio *bio)
{
        return true;
}

static inline bool bio_crypt_ctx_back_mergeable(struct request *req,
                                                struct bio *bio)
{
        return true;
}

static inline bool bio_crypt_ctx_merge_rq(struct request *req,
                                          struct request *next)
{
        return true;
}

static inline void blk_crypto_rq_set_defaults(struct request *rq) { }

static inline bool blk_crypto_rq_is_encrypted(struct request *rq)
{
        return false;
}

#endif /* CONFIG_BLK_INLINE_ENCRYPTION */

void __bio_crypt_advance(struct bio *bio, unsigned int bytes);
static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
{
        if (bio_has_crypt_ctx(bio))
                __bio_crypt_advance(bio, bytes);
}

void __bio_crypt_free_ctx(struct bio *bio);
static inline void bio_crypt_free_ctx(struct bio *bio)
{
        if (bio_has_crypt_ctx(bio))
                __bio_crypt_free_ctx(bio);
}

static inline void bio_crypt_do_front_merge(struct request *rq,
                                            struct bio *bio)
{
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
        if (bio_has_crypt_ctx(bio))
                memcpy(rq->crypt_ctx->bc_dun, bio->bi_crypt_context->bc_dun,
                       sizeof(rq->crypt_ctx->bc_dun));
#endif
}

bool __blk_crypto_bio_prep(struct bio **bio_ptr);
static inline bool blk_crypto_bio_prep(struct bio **bio_ptr)
{
        if (bio_has_crypt_ctx(*bio_ptr))
                return __blk_crypto_bio_prep(bio_ptr);
        return true;
}

blk_status_t __blk_crypto_init_request(struct request *rq);
static inline blk_status_t blk_crypto_init_request(struct request *rq)
{
        if (blk_crypto_rq_is_encrypted(rq))
                return __blk_crypto_init_request(rq);
        return BLK_STS_OK;
}

void __blk_crypto_free_request(struct request *rq);
static inline void blk_crypto_free_request(struct request *rq)
{
        if (blk_crypto_rq_is_encrypted(rq))
                __blk_crypto_free_request(rq);
}

int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
                             gfp_t gfp_mask);
/**
 * blk_crypto_rq_bio_prep - Prepare a request's crypt_ctx when its first bio
 *                          is inserted
 * @rq: The request to prepare
 * @bio: The first bio being inserted into the request
 * @gfp_mask: Memory allocation flags
 *
 * Return: 0 on success, -ENOMEM if out of memory.  -ENOMEM is only possible if
 *         @gfp_mask doesn't include %__GFP_DIRECT_RECLAIM.
 */
static inline int blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
                                         gfp_t gfp_mask)
{
        if (bio_has_crypt_ctx(bio))
                return __blk_crypto_rq_bio_prep(rq, bio, gfp_mask);
        return 0;
}

/**
 * blk_crypto_insert_cloned_request - Prepare a cloned request to be inserted
 *                                    into a request queue.
 * @rq: the request being queued
 *
 * Return: BLK_STS_OK on success, nonzero on error.
 */
static inline blk_status_t blk_crypto_insert_cloned_request(struct request *rq)
{

        if (blk_crypto_rq_is_encrypted(rq))
                return blk_crypto_init_request(rq);
        return BLK_STS_OK;
}

#ifdef CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK

int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num);

bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr);

int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key);

#else /* CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK */

static inline int
blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
{
        pr_warn_once("crypto API fallback is disabled\n");
        return -ENOPKG;
}

static inline bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
{
        pr_warn_once("crypto API fallback disabled; failing request.\n");
        (*bio_ptr)->bi_status = BLK_STS_NOTSUPP;
        return false;
}

static inline int
blk_crypto_fallback_evict_key(const struct blk_crypto_key *key)
{
        return 0;
}

#endif /* CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK */

#endif /* __LINUX_BLK_CRYPTO_INTERNAL_H */