/usr/include/liberasurecode/erasurecode.h is in liberasurecode-dev 1.4.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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* Copyright 2014, Tushar Gohad, Kevin Greenan, All rights reserved
*
* 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. THIS SOFTWARE IS PROVIDED BY
* THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* liberasurecode frontend API header
*
* vi: set noai tw=79 ts=4 sw=4:
*/
#ifndef _ERASURECODE_H_
#define _ERASURECODE_H_
#include "erasurecode_stdinc.h"
#include "erasurecode_version.h"
#define EC_MAX_FRAGMENTS 32
#ifdef __cplusplus
extern "C" {
#endif
/* =~=*=~==~=*=~==~=*=~= Supported EC backends =~=*=~==~=*=~==~=*=~==~=*=~== */
typedef enum {
EC_BACKEND_NULL = 0,
EC_BACKEND_JERASURE_RS_VAND = 1,
EC_BACKEND_JERASURE_RS_CAUCHY = 2,
EC_BACKEND_FLAT_XOR_HD = 3,
EC_BACKEND_ISA_L_RS_VAND = 4,
EC_BACKEND_SHSS = 5,
EC_BACKEND_LIBERASURECODE_RS_VAND = 6,
EC_BACKEND_ISA_L_RS_CAUCHY = 7,
EC_BACKENDS_MAX,
} ec_backend_id_t;
/* ~=*=~==~=*=~= EC Fragment metadata - supported checksum types ~=*=~==~=*=~ */
/* Checksum types supported for fragment metadata stored in each fragment */
typedef enum {
CHKSUM_NONE = 1,
CHKSUM_CRC32 = 2,
CHKSUM_MD5 = 3,
CHKSUM_TYPES_MAX,
} ec_checksum_type_t;
/* =~=*=~==~=*=~== EC Arguments - Common and backend-specific =~=*=~==~=*=~== */
/**
* Common and backend-specific args
* to be passed to liberasurecode_instance_create()
*/
struct ec_args {
int k; /* number of data fragments */
int m; /* number of parity fragments */
int w; /* word size, in bits (optional) */
int hd; /* hamming distance (=m for Reed-Solomon) */
union {
struct {
uint64_t arg1; /* sample arg */
} null_args; /* args specific to the null codes */
struct {
uint64_t x, y; /* reserved for future expansion */
uint64_t z, a; /* reserved for future expansion */
} reserved;
} priv_args1;
void *priv_args2; /** flexible placeholder for
* future backend args */
ec_checksum_type_t ct; /* fragment checksum type */
};
/* =~=*=~==~=*=~== liberasurecode frontend API functions =~=*=~==~=~=*=~==~= */
/* liberasurecode frontend API functions */
/**
* Checks if a given backend is available.
*
* @param backend_id - one of the supported backends.
*
* @returns 1 if a backend is available; 0 otherwise
*/
int liberasurecode_backend_available(const ec_backend_id_t backend_id);
/**
* Create a liberasurecode instance and return a descriptor
* for use with EC operations (encode, decode, reconstruct)
*
* @param id - one of the supported backends as
* defined by ec_backend_id_t
* @param ec_args - arguments to the EC backend
* arguments common to all backends
* k - number of data fragments
* m - number of parity fragments
* w - word size, in bits
* hd - hamming distance (=m for Reed-Solomon)
* ct - fragment checksum type (stored with the fragment metadata)
* backend-specific arguments
* null_args - arguments for the null backend
* flat_xor_hd, jerasure do not require any special args
*
* @return liberasurecode instance descriptor (int > 0)
*/
int liberasurecode_instance_create(const ec_backend_id_t id,
struct ec_args *args);
/**
* Close a liberasurecode instance
*
* @param desc - liberasurecode descriptor to close
*
* @return 0 on success, otherwise non-zero error code
*/
int liberasurecode_instance_destroy(int desc);
/**
* Erasure encode a data buffer
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param orig_data - data to encode
* @param orig_data_size - length of data to encode
* @param encoded_data - pointer to _output_ array (char **) of k data
* fragments (char *), allocated by the callee
* @param encoded_parity - pointer to _output_ array (char **) of m parity
* fragments (char *), allocated by the callee
* @param fragment_len - pointer to _output_ length of each fragment, assuming
* all fragments are the same length
*
* @return 0 on success, -error code otherwise
*/
int liberasurecode_encode(int desc,
const char *orig_data, uint64_t orig_data_size, /* input */
char ***encoded_data, char ***encoded_parity, /* output */
uint64_t *fragment_len); /* output */
/**
* Cleanup structures allocated by librasurecode_encode
*
* The caller has no context, so cannot safely free memory
* allocated by liberasurecode, so it must pass the
* deallocation responsibility back to liberasurecode.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param encoded_data - (char **) array of k data
* fragments (char *), allocated by liberasurecode_encode
* @param encoded_parity - (char **) array of m parity
* fragments (char *), allocated by liberasurecode_encode
*
* @return 0 in success; -error otherwise
*/
int liberasurecode_encode_cleanup(int desc, char **encoded_data,
char **encoded_parity);
/**
* Reconstruct original data from a set of k encoded fragments
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param fragments - erasure encoded fragments (> = k)
* @param num_fragments - number of fragments being passed in
* @param fragment_len - length of each fragment (assume they are the same)
* @param force_metadata_checks - force fragment metadata checks (default: 0)
* @param out_data - _output_ pointer to decoded data
* @param out_data_len - _output_ length of decoded output
* (both output data pointers are allocated by liberasurecode,
* caller invokes liberasurecode_decode_clean() after it has
* read decoded data in 'out_data')
*
* @return 0 on success, -error code otherwise
*/
int liberasurecode_decode(int desc,
char **available_fragments, /* input */
int num_fragments, uint64_t fragment_len, /* input */
int force_metadata_checks, /* input */
char **out_data, uint64_t *out_data_len); /* output */
/**
* Cleanup structures allocated by librasurecode_decode
*
* The caller has no context, so cannot safely free memory
* allocated by liberasurecode, so it must pass the
* deallocation responsibility back to liberasurecode.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param data - (char *) buffer of data decoded by librasurecode_decode
*
* @return 0 on success; -error otherwise
*/
int liberasurecode_decode_cleanup(int desc, char *data);
/**
* Reconstruct a missing fragment from a subset of available fragments
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param available_fragments - erasure encoded fragments
* @param num_fragments - number of fragments being passed in
* @param fragment_len - size in bytes of the fragments
* @param destination_idx - missing idx to reconstruct
* @param out_fragment - output of reconstruct
*
* @return 0 on success, -error code otherwise
*/
int liberasurecode_reconstruct_fragment(int desc,
char **available_fragments, /* input */
int num_fragments, uint64_t fragment_len, /* input */
int destination_idx, /* input */
char* out_fragment); /* output */
/**
* Return a list of lists with valid rebuild indexes given
* a list of missing indexes.
*
* @desc: liberasurecode instance descriptor (obtained with
* liberasurecode_instance_create)
* @fragments_to_reconstruct list of indexes to reconstruct
* @fragments_to_exclude list of indexes to exclude from
* reconstruction equation
* @fragments_needed list of fragments needed to reconstruct
* fragments in fragments_to_reconstruct
*
* @return 0 on success, non-zero on error
*/
int liberasurecode_fragments_needed(int desc,
int *fragments_to_reconstruct,
int *fragments_to_exclude,
int *fragments_needed);
/* ==~=*=~==~=*=~== liberasurecode fragment metadata routines ==~*==~=*=~==~ */
#define LIBERASURECODE_MAX_CHECKSUM_LEN 8
typedef struct __attribute__((__packed__))
fragment_metadata
{
uint32_t idx; /* 4 */
uint32_t size; /* 4 */
uint32_t frag_backend_metadata_size; /* 4 */
uint64_t orig_data_size; /* 8 */
uint8_t chksum_type; /* 1 */
uint32_t chksum[LIBERASURECODE_MAX_CHECKSUM_LEN]; /* 32 */
uint8_t chksum_mismatch; /* 1 */
uint8_t backend_id; /* 1 */
uint32_t backend_version; /* 4 */
} fragment_metadata_t;
/**
* Get opaque metadata for a fragment. The metadata is opaque to the
* client, but meaningful to the underlying library. It is used to verify
* stripes in verify_stripe_metadata().
*
* @param fragment - fragment data pointer
* @param fragment_metadata - pointer to allocated buffer of size at least
* sizeof(struct fragment_metadata) to hold fragment metadata struct
*
* @return 0 on success, non-zero on error
*/
//EDL: This needs to be implemented
int liberasurecode_get_fragment_metadata(char *fragment,
fragment_metadata_t *fragment_metadata);
/**
* Verify that the specified pointer points to a well formed fragment that can
* be processed by both this instance of liberasurecode and the specified
* backend.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param fragment - fragment to verify
*
* @return 1 if fragment validation fails, 0 otherwise.
*/
int is_invalid_fragment(int desc, char *fragment);
/**
* Verify a subset of fragments generated by encode()
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param fragments - fragments part of the EC stripe to verify
* @param num_fragments - number of fragments part of the EC stripe
*
* @return 1 if stripe checksum verification is successful, 0 otherwise
*/
int liberasurecode_verify_stripe_metadata(int desc,
char **fragments, int num_fragments);
/* ==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~== */
/**
* liberasurecode fragment header definition
*
* Prevent the compiler from padding this by using the __packed__ keyword
*/
#define LIBERASURECODE_FRAG_HEADER_MAGIC 0xb0c5ecc
#define LIBERASURECODE_MAX_CHECKSUM_LEN 8 /* quad words */
typedef struct __attribute__((__packed__)) fragment_header_s
{
fragment_metadata_t meta; /* 59 bytes */
uint32_t magic; /* 4 bytes */
uint32_t libec_version; /* 4 bytes */
uint32_t metadata_chksum; /* 4 bytes */
// We must be aligned to 16-byte boundaries
// So, size this array accordingly
uint8_t aligned_padding[9];
} fragment_header_t;
#define FRAGSIZE_2_BLOCKSIZE(fragment_size) \
(fragment_size - sizeof(fragment_header_t))
/* ==~=*=~===~=*=~==~=*=~== liberasurecode Helpers ==~*==~=*=~==~=~=*=~==~= */
/**
* This computes the aligned size of a buffer passed into
* the encode function. The encode function must pad fragments
* to be algined with the word size (w) and the last fragment also
* needs to be aligned. This computes the sum of the algined fragment
* sizes for a given buffer to encode.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param data_len - original data length in bytes
*
* @return aligned length, or -error code on error
*/
int liberasurecode_get_aligned_data_size(int desc, uint64_t data_len);
/**
* This will return the minimum encode size, which is the minimum
* buffer size that can be encoded.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
*
* @return minimum data length length, or -error code on error
*/
int liberasurecode_get_minimum_encode_size(int desc);
/**
* This will return the fragment size, which is each fragment data
* length the backend will allocate when encoding.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param data_len - original data length in bytes
*
* @return fragment size - sizeof(fragment_header) + size
* + frag_backend_metadata_size
* if an error, return value will be negative
*/
int liberasurecode_get_fragment_size(int desc, int data_len);
/**
* This will return the liberasurecode version for the descriptor
*
* @return version uint32_t - from erasurecode_version.h
*/
uint32_t liberasurecode_get_version();
/* ==~=*=~===~=*=~==~=*=~== liberasurecode Error codes =~=*=~==~=~=*=~==~== */
/* Error codes */
typedef enum {
EBACKENDNOTSUPP = 200,
EECMETHODNOTIMPL = 201,
EBACKENDINITERR = 202,
EBACKENDINUSE = 203,
EBACKENDNOTAVAIL = 204,
EBADCHKSUM = 205,
EINVALIDPARAMS = 206,
EBADHEADER = 207,
EINSUFFFRAGS = 208,
} LIBERASURECODE_ERROR_CODES;
/* =~=*=~==~=*=~==~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~= */
#ifdef __cplusplus
}
#endif
#endif // _ERASURECODE_H_
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