#include <config.h>
#include <isc/entropy.h>
#include <isc/hash.h>
#include <isc/mem.h>
#include <isc/magic.h>
#include <isc/mutex.h>
#include <isc/once.h>
#include <isc/random.h>
#include <isc/refcount.h>
#include <isc/string.h>
#include <isc/util.h>
#define HASH_MAGIC ISC_MAGIC('H', 'a', 's', 'h')
#define VALID_HASH(h) ISC_MAGIC_VALID((h), HASH_MAGIC)
#define PRIME32 0xFFFFFFFB
typedef isc_uint32_t hash_accum_t;
typedef isc_uint16_t hash_random_t;
struct isc_hash {
unsigned int magic;
isc_mem_t *mctx;
isc_mutex_t lock;
isc_boolean_t initialized;
isc_refcount_t refcnt;
isc_entropy_t *entropy;
unsigned int limit;
size_t vectorlen;
hash_random_t *rndvector;
};
static isc_mutex_t createlock;
static isc_once_t once = ISC_ONCE_INIT;
static isc_hash_t *hash = NULL;
static unsigned char maptolower[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
};
isc_result_t
isc_hash_ctxcreate(isc_mem_t *mctx, isc_entropy_t *entropy,
unsigned int limit, isc_hash_t **hctxp)
{
isc_result_t result;
isc_hash_t *hctx;
size_t vlen;
hash_random_t *rv;
hash_accum_t overflow_limit;
REQUIRE(mctx != NULL);
REQUIRE(hctxp != NULL && *hctxp == NULL);
overflow_limit =
1 << (((sizeof(hash_accum_t) - sizeof(hash_random_t))) * 8);
if (overflow_limit < (limit + 1) * 0xff)
return (ISC_R_RANGE);
hctx = isc_mem_get(mctx, sizeof(isc_hash_t));
if (hctx == NULL)
return (ISC_R_NOMEMORY);
vlen = sizeof(hash_random_t) * (limit + 1);
rv = isc_mem_get(mctx, vlen);
if (rv == NULL) {
result = ISC_R_NOMEMORY;
goto errout;
}
result = isc_mutex_init(&hctx->lock);
if (result != ISC_R_SUCCESS)
goto errout;
hctx->magic = HASH_MAGIC;
hctx->mctx = NULL;
isc_mem_attach(mctx, &hctx->mctx);
hctx->initialized = ISC_FALSE;
result = isc_refcount_init(&hctx->refcnt, 1);
if (result != ISC_R_SUCCESS)
goto cleanup_lock;
hctx->entropy = NULL;
hctx->limit = limit;
hctx->vectorlen = vlen;
hctx->rndvector = rv;
if (entropy != NULL)
isc_entropy_attach(entropy, &hctx->entropy);
*hctxp = hctx;
return (ISC_R_SUCCESS);
cleanup_lock:
DESTROYLOCK(&hctx->lock);
errout:
isc_mem_put(mctx, hctx, sizeof(isc_hash_t));
if (rv != NULL)
isc_mem_put(mctx, rv, vlen);
return (result);
}
static void
initialize_lock(void) {
RUNTIME_CHECK(isc_mutex_init(&createlock) == ISC_R_SUCCESS);
}
isc_result_t
isc_hash_create(isc_mem_t *mctx, isc_entropy_t *entropy, size_t limit) {
isc_result_t result = ISC_R_SUCCESS;
REQUIRE(mctx != NULL);
INSIST(hash == NULL);
RUNTIME_CHECK(isc_once_do(&once, initialize_lock) == ISC_R_SUCCESS);
LOCK(&createlock);
if (hash == NULL)
result = isc_hash_ctxcreate(mctx, entropy, limit, &hash);
UNLOCK(&createlock);
return (result);
}
void
isc_hash_ctxinit(isc_hash_t *hctx) {
isc_result_t result;
LOCK(&hctx->lock);
if (hctx->initialized == ISC_TRUE)
goto out;
if (hctx->entropy) {
result = isc_entropy_getdata(hctx->entropy,
hctx->rndvector, hctx->vectorlen,
NULL, 0);
INSIST(result == ISC_R_SUCCESS);
} else {
isc_uint32_t pr;
unsigned int i, copylen;
unsigned char *p;
p = (unsigned char *)hctx->rndvector;
for (i = 0; i < hctx->vectorlen; i += copylen, p += copylen) {
isc_random_get(&pr);
if (i + sizeof(pr) <= hctx->vectorlen)
copylen = sizeof(pr);
else
copylen = hctx->vectorlen - i;
memcpy(p, &pr, copylen);
}
INSIST(p == (unsigned char *)hctx->rndvector +
hctx->vectorlen);
}
hctx->initialized = ISC_TRUE;
out:
UNLOCK(&hctx->lock);
}
void
isc_hash_init() {
INSIST(hash != NULL && VALID_HASH(hash));
isc_hash_ctxinit(hash);
}
void
isc_hash_ctxattach(isc_hash_t *hctx, isc_hash_t **hctxp) {
REQUIRE(VALID_HASH(hctx));
REQUIRE(hctxp != NULL && *hctxp == NULL);
isc_refcount_increment(&hctx->refcnt, NULL);
*hctxp = hctx;
}
static void
destroy(isc_hash_t **hctxp) {
isc_hash_t *hctx;
isc_mem_t *mctx;
REQUIRE(hctxp != NULL && *hctxp != NULL);
hctx = *hctxp;
*hctxp = NULL;
LOCK(&hctx->lock);
isc_refcount_destroy(&hctx->refcnt);
mctx = hctx->mctx;
if (hctx->entropy != NULL)
isc_entropy_detach(&hctx->entropy);
if (hctx->rndvector != NULL)
isc_mem_put(mctx, hctx->rndvector, hctx->vectorlen);
UNLOCK(&hctx->lock);
DESTROYLOCK(&hctx->lock);
memset(hctx, 0, sizeof(isc_hash_t));
isc_mem_put(mctx, hctx, sizeof(isc_hash_t));
isc_mem_detach(&mctx);
}
void
isc_hash_ctxdetach(isc_hash_t **hctxp) {
isc_hash_t *hctx;
unsigned int refs;
REQUIRE(hctxp != NULL && VALID_HASH(*hctxp));
hctx = *hctxp;
isc_refcount_decrement(&hctx->refcnt, &refs);
if (refs == 0)
destroy(&hctx);
*hctxp = NULL;
}
void
isc_hash_destroy() {
unsigned int refs;
INSIST(hash != NULL && VALID_HASH(hash));
isc_refcount_decrement(&hash->refcnt, &refs);
INSIST(refs == 0);
destroy(&hash);
}
static inline unsigned int
hash_calc(isc_hash_t *hctx, const unsigned char *key, unsigned int keylen,
isc_boolean_t case_sensitive)
{
hash_accum_t partial_sum = 0;
hash_random_t *p = hctx->rndvector;
unsigned int i = 0;
if (hctx->initialized == ISC_FALSE)
isc_hash_ctxinit(hctx);
if (case_sensitive) {
for (i = 0; i < keylen; i++)
partial_sum += key[i] * (hash_accum_t)p[i];
} else {
for (i = 0; i < keylen; i++)
partial_sum += maptolower[key[i]] * (hash_accum_t)p[i];
}
partial_sum += p[i];
return ((unsigned int)(partial_sum % PRIME32));
}
unsigned int
isc_hash_ctxcalc(isc_hash_t *hctx, const unsigned char *key,
unsigned int keylen, isc_boolean_t case_sensitive)
{
REQUIRE(hctx != NULL && VALID_HASH(hctx));
REQUIRE(keylen <= hctx->limit);
return (hash_calc(hctx, key, keylen, case_sensitive));
}
unsigned int
isc_hash_calc(const unsigned char *key, unsigned int keylen,
isc_boolean_t case_sensitive)
{
INSIST(hash != NULL && VALID_HASH(hash));
REQUIRE(keylen <= hash->limit);
return (hash_calc(hash, key, keylen, case_sensitive));
}