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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright (c) 2018 Linaro Limited
*/
#include <stdio.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <odp/api/hash.h>
#include <odp/api/hints.h>
#include <odp/api/rwlock.h>
#include <odp/api/shared_memory.h>
#include <odp_debug_internal.h>
#include <odp_init_internal.h>
typedef struct crc_table_t {
uint32_t crc[256];
uint32_t width;
uint32_t poly;
int reflect;
odp_rwlock_t rwlock;
odp_shm_t shm;
} crc_table_t;
static crc_table_t *crc_table;
int _odp_hash_init_global(void)
{
odp_shm_t shm;
shm = odp_shm_reserve("_odp_hash_crc_gen", sizeof(crc_table_t),
ODP_CACHE_LINE_SIZE, 0);
crc_table = odp_shm_addr(shm);
if (crc_table == NULL) {
_ODP_ERR("Shm reserve failed for odp_hash_crc_gen\n");
return -1;
}
memset(crc_table, 0, sizeof(crc_table_t));
crc_table->shm = shm;
odp_rwlock_init(&crc_table->rwlock);
return 0;
}
int _odp_hash_term_global(void)
{
if (odp_shm_free(crc_table->shm)) {
_ODP_ERR("Shm free failed for odp_hash_crc_gen\n");
return -1;
}
return 0;
}
/* Reflect bits in a byte */
static inline uint8_t reflect_u8(uint8_t byte)
{
uint8_t u8[8];
u8[0] = (byte & (0x1u << 7)) >> 7;
u8[1] = (byte & (0x1u << 6)) >> 5;
u8[2] = (byte & (0x1u << 5)) >> 3;
u8[3] = (byte & (0x1u << 4)) >> 1;
u8[4] = (byte & (0x1u << 3)) << 1;
u8[5] = (byte & (0x1u << 2)) << 3;
u8[6] = (byte & (0x1u << 1)) << 5;
u8[7] = (byte & 0x1u) << 7;
return u8[0] | u8[1] | u8[2] | u8[3] | u8[4] | u8[5] | u8[6] | u8[7];
}
/* Reflect 32 bits */
static inline uint32_t reflect_u32(uint32_t u32)
{
uint32_t r[4];
r[0] = reflect_u8((u32 & 0xff000000u) >> 24);
r[1] = reflect_u8((u32 & 0x00ff0000u) >> 16);
r[2] = reflect_u8((u32 & 0x0000ff00u) >> 8);
r[3] = reflect_u8(u32 & 0xffu);
return (r[3] << 24) | (r[2] << 16) | (r[1] << 8) | r[0];
}
/* Reflect 24 bits */
static inline uint32_t reflect_u24(uint32_t u32)
{
uint32_t r[4];
r[0] = reflect_u8((u32 & 0xff0000u) >> 16);
r[1] = reflect_u8((u32 & 0x00ff00u) >> 8);
r[2] = reflect_u8(u32 & 0xffu);
return (r[2] << 16) | (r[1] << 8) | r[0];
}
/* Reflect 16 bits */
static inline uint32_t reflect_u16(uint32_t u32)
{
uint32_t r[4];
r[0] = reflect_u8((u32 & 0xff00u) >> 8);
r[1] = reflect_u8(u32 & 0xffu);
return (r[1] << 8) | r[0];
}
/* Generate table for a 32/24/16 bit CRCs.
*
* Based on an example in RFC 1952.
*/
static inline void crc_table_gen(uint32_t poly, int reflect, int width)
{
uint32_t i, crc, bit, shift, msb, mask;
crc_table->width = width;
crc_table->poly = poly;
crc_table->reflect = reflect;
shift = width - 8;
mask = 0xffffffffu >> (32 - width);
msb = 0x1u << (width - 1);
if (reflect) {
if (width == 32)
poly = reflect_u32(poly);
else if (width == 24)
poly = reflect_u24(poly);
else
poly = reflect_u16(poly);
}
for (i = 0; i < 256; i++) {
if (reflect) {
crc = i;
for (bit = 0; bit < 8; bit++) {
if (crc & 0x1u)
crc = poly ^ (crc >> 1);
else
crc = crc >> 1;
}
} else {
crc = i << shift;
for (bit = 0; bit < 8; bit++) {
if (crc & msb)
crc = poly ^ (crc << 1);
else
crc = crc << 1;
}
}
crc_table->crc[i] = crc & mask;
}
}
static inline uint32_t crc_calc(const uint8_t *data, uint32_t data_len,
uint32_t init_val, int reflect, int width)
{
uint32_t i, crc, shift;
uint8_t byte;
uint32_t mask;
shift = width - 8;
mask = 0xffffffffu >> (32 - width);
crc = init_val;
for (i = 0; i < data_len; i++) {
byte = data[i];
if (reflect) {
crc = crc_table->crc[(crc ^ byte) & 0xffu] ^ (crc >> 8);
} else {
crc = crc_table->crc[(crc >> shift) ^ byte] ^
(crc << 8);
crc = crc & mask;
}
}
return crc;
}
int odp_hash_crc_gen64(const void *data_ptr, uint32_t data_len,
uint64_t init_val, odp_hash_crc_param_t *crc_param,
uint64_t *crc_out)
{
uint32_t crc;
int update_table;
uint32_t poly = crc_param->poly;
uint32_t width = crc_param->width;
int reflect = crc_param->reflect_in;
if (odp_unlikely(crc_param->reflect_in != crc_param->reflect_out)) {
_ODP_ERR("Odd reflection setting not supported.\n");
return -1;
}
if (odp_unlikely(width != 32 && width != 24 && width != 16)) {
_ODP_ERR("CRC width %" PRIu32 " bits not supported.\n", width);
return -1;
}
/* TODO: fix implementation of 24 bit CRC with reflection */
if (odp_unlikely(width == 24 && reflect)) {
_ODP_ERR("24 bit CRC with reflection not supported.\n");
return -1;
}
odp_rwlock_read_lock(&crc_table->rwlock);
update_table = (crc_table->width != width) ||
(crc_table->poly != poly) ||
(crc_table->reflect != reflect);
/* Generate CRC table if not yet generated. */
if (odp_unlikely(update_table)) {
odp_rwlock_read_unlock(&crc_table->rwlock);
odp_rwlock_write_lock(&crc_table->rwlock);
crc_table_gen(poly, reflect, width);
}
crc = crc_calc(data_ptr, data_len, init_val, reflect, width);
if (odp_unlikely(update_table))
odp_rwlock_write_unlock(&crc_table->rwlock);
else
odp_rwlock_read_unlock(&crc_table->rwlock);
if (crc_param->xor_out)
crc = crc ^ (uint32_t)crc_param->xor_out;
*crc_out = crc;
return 0;
}
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