hv_func.h revision 1.12 
1/* hash a key
2 *--------------------------------------------------------------------------------------
3 * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
4 * to avoid "algorithmic complexity attacks".
5 *
6 * If USE_HASH_SEED is defined, hash randomisation is done by default
7 * (see also perl.c:perl_parse() and S_init_tls_and_interp() and util.c:get_hash_seed())
8 */
9#ifndef PERL_SEEN_HV_FUNC_H_ /* compile once */
10#define PERL_SEEN_HV_FUNC_H_
11#include "hv_macro.h"
12
13#if !( 0 \
14        || defined(PERL_HASH_FUNC_SIPHASH) \
15        || defined(PERL_HASH_FUNC_SIPHASH13) \
16        || defined(PERL_HASH_FUNC_ZAPHOD32) \
17    )
18#   ifdef CAN64BITHASH
19#       define PERL_HASH_FUNC_SIPHASH13
20#   else
21#       define PERL_HASH_FUNC_ZAPHOD32
22#   endif
23#endif
24
25#ifndef PERL_HASH_USE_SBOX32_ALSO
26#define PERL_HASH_USE_SBOX32_ALSO 1
27#endif
28
29#ifndef SBOX32_MAX_LEN
30#define SBOX32_MAX_LEN 24
31#endif
32
33/* this must be after the SBOX32_MAX_LEN define */
34#include "sbox32_hash.h"
35
36#if defined(PERL_HASH_FUNC_SIPHASH)
37# define __PERL_HASH_FUNC "SIPHASH_2_4"
38# define __PERL_HASH_WORD_TYPE U64
39# define __PERL_HASH_WORD_SIZE sizeof(__PERL_HASH_WORD_TYPE)
40# define __PERL_HASH_SEED_BYTES (__PERL_HASH_WORD_SIZE * 2)
41# define __PERL_HASH_STATE_BYTES (__PERL_HASH_WORD_SIZE * 4)
42# define __PERL_HASH_SEED_STATE(seed,state) S_perl_siphash_seed_state(seed,state)
43# define __PERL_HASH_WITH_STATE(state,str,len) S_perl_hash_siphash_2_4_with_state((state),(U8*)(str),(len))
44#elif defined(PERL_HASH_FUNC_SIPHASH13)
45# define __PERL_HASH_FUNC "SIPHASH_1_3"
46# define __PERL_HASH_WORD_TYPE U64
47# define __PERL_HASH_WORD_SIZE sizeof(__PERL_HASH_WORD_TYPE)
48# define __PERL_HASH_SEED_BYTES (__PERL_HASH_WORD_SIZE * 2)
49# define __PERL_HASH_STATE_BYTES (__PERL_HASH_WORD_SIZE * 4)
50# define __PERL_HASH_SEED_STATE(seed,state) S_perl_siphash_seed_state(seed,state)
51# define __PERL_HASH_WITH_STATE(state,str,len) S_perl_hash_siphash_1_3_with_state((state),(U8*)(str),(len))
52#elif defined(PERL_HASH_FUNC_ZAPHOD32)
53# define __PERL_HASH_FUNC "ZAPHOD32"
54# define __PERL_HASH_WORD_TYPE U32
55# define __PERL_HASH_WORD_SIZE sizeof(__PERL_HASH_WORD_TYPE)
56# define __PERL_HASH_SEED_BYTES (__PERL_HASH_WORD_SIZE * 3)
57# define __PERL_HASH_STATE_BYTES (__PERL_HASH_WORD_SIZE * 3)
58# define __PERL_HASH_SEED_STATE(seed,state) zaphod32_seed_state(seed,state)
59# define __PERL_HASH_WITH_STATE(state,str,len) (U32)zaphod32_hash_with_state((state),(U8*)(str),(len))
60# include "zaphod32_hash.h"
61#endif
62
63#ifndef __PERL_HASH_WITH_STATE
64#error "No hash function defined!"
65#endif
66#ifndef __PERL_HASH_SEED_BYTES
67#error "__PERL_HASH_SEED_BYTES not defined"
68#endif
69#ifndef __PERL_HASH_FUNC
70#error "__PERL_HASH_FUNC not defined"
71#endif
72
73/* Some siphash static functions are needed by XS::APItest even when
74   siphash isn't the current hash.  For SipHash builds this needs to
75   be before the S_perl_hash_with_seed() definition.
76*/
77#include "perl_siphash.h"
78
79#define __PERL_HASH_SEED_roundup(x, y)   ( ( ( (x) + ( (y) - 1 ) ) / (y) ) * (y) )
80#define _PERL_HASH_SEED_roundup(x) __PERL_HASH_SEED_roundup(x,__PERL_HASH_WORD_SIZE)
81
82#define PL_hash_seed ((U8 *)PL_hash_seed_w)
83#define PL_hash_state ((U8 *)PL_hash_state_w)
84
85#if PERL_HASH_USE_SBOX32_ALSO != 1
86# define _PERL_HASH_FUNC                        __PERL_HASH_FUNC
87# define _PERL_HASH_SEED_BYTES                  __PERL_HASH_SEED_BYTES
88# define _PERL_HASH_STATE_BYTES                 __PERL_HASH_STATE_BYTES
89# define _PERL_HASH_SEED_STATE(seed,state)      __PERL_HASH_SEED_STATE(seed,state)
90# define _PERL_HASH_WITH_STATE(state,str,len)   __PERL_HASH_WITH_STATE(state,str,len)
91#else
92
93#define _PERL_HASH_FUNC         "SBOX32_WITH_" __PERL_HASH_FUNC
94/* note the 4 in the below code comes from the fact the seed to initialize the SBOX is 128 bits */
95#define _PERL_HASH_SEED_BYTES   ( __PERL_HASH_SEED_BYTES + (int)( 4 * sizeof(U32)) )
96
97#define _PERL_HASH_STATE_BYTES  \
98    ( __PERL_HASH_STATE_BYTES + ( ( 1 + ( 256 * SBOX32_MAX_LEN ) ) * sizeof(U32) ) )
99
100#define _PERL_HASH_SEED_STATE(seed,state) STMT_START {                                      \
101    __PERL_HASH_SEED_STATE(seed,state);                                                     \
102    sbox32_seed_state128(seed + __PERL_HASH_SEED_BYTES, state + __PERL_HASH_STATE_BYTES);    \
103} STMT_END
104
105#define _PERL_HASH_WITH_STATE(state,str,len)                                            \
106    (LIKELY(len <= SBOX32_MAX_LEN)                                                      \
107        ? sbox32_hash_with_state((state + __PERL_HASH_STATE_BYTES),(U8*)(str),(len))    \
108        : __PERL_HASH_WITH_STATE((state),(str),(len)))
109
110#endif
111
112#define PERL_HASH_WITH_SEED(seed,hash,str,len) \
113    (hash) = S_perl_hash_with_seed((const U8 *) seed, (const U8 *) str,len)
114#define PERL_HASH_WITH_STATE(state,hash,str,len) \
115    (hash) = _PERL_HASH_WITH_STATE((state),(U8*)(str),(len))
116
117#define PERL_HASH_SEED_STATE(seed,state) _PERL_HASH_SEED_STATE(seed,state)
118#define PERL_HASH_SEED_BYTES _PERL_HASH_SEED_roundup(_PERL_HASH_SEED_BYTES)
119#define PERL_HASH_STATE_BYTES _PERL_HASH_SEED_roundup(_PERL_HASH_STATE_BYTES)
120#define PERL_HASH_FUNC        _PERL_HASH_FUNC
121
122#define PERL_HASH_SEED_WORDS (PERL_HASH_SEED_BYTES/__PERL_HASH_WORD_SIZE)
123#define PERL_HASH_STATE_WORDS (PERL_HASH_STATE_BYTES/__PERL_HASH_WORD_SIZE)
124
125#ifdef PERL_USE_SINGLE_CHAR_HASH_CACHE
126#define PERL_HASH(state,str,len) \
127    (hash) = ((len) < 2 ? ( (len) == 0 ? PL_hash_chars[256] : PL_hash_chars[(U8)(str)[0]] ) \
128                       : _PERL_HASH_WITH_STATE(PL_hash_state,(U8*)(str),(len)))
129#else
130#define PERL_HASH(hash,str,len) \
131    PERL_HASH_WITH_STATE(PL_hash_state,hash,(U8*)(str),(len))
132#endif
133
134/* Setup the hash seed, either we do things dynamically at start up,
135 * including reading from the environment, or we randomly setup the
136 * seed. The seed will be passed into the PERL_HASH_SEED_STATE() function
137 * defined for the configuration defined for this perl, which will then
138 * initialize whatever state it might need later in hashing. */
139
140#ifndef PERL_HASH_SEED
141#   if defined(USE_HASH_SEED)
142#       define PERL_HASH_SEED PL_hash_seed
143#   else
144       /* this is a 512 bit seed, which should be more than enough for the
145        * configuration of any of our hash functions (with or without sbox).
146        * If you actually use a hard coded seed, you are strongly encouraged
147        * to replace this with something else of the correct length
148        * for the hash function you are using (24-32 bytes depending on build
149        * options). Repeat, you are *STRONGLY* encouraged not to use the value
150        * provided here.
151        */
152#       define PERL_HASH_SEED \
153           ((const U8 *)"A long string of pseudorandomly "  \
154                        "chosen bytes for hashing in Perl")
155#   endif
156#endif
157
158/* legacy - only mod_perl should be doing this.  */
159#ifdef PERL_HASH_INTERNAL_ACCESS
160#define PERL_HASH_INTERNAL(hash,str,len) PERL_HASH(hash,str,len)
161#endif
162
163PERL_STATIC_INLINE U32
164S_perl_hash_with_seed(const U8 * seed, const U8 *str, STRLEN len) {
165    __PERL_HASH_WORD_TYPE state[PERL_HASH_STATE_WORDS];
166    _PERL_HASH_SEED_STATE(seed,(U8*)state);
167    return _PERL_HASH_WITH_STATE((U8*)state,str,len);
168}
169
170#endif /*compile once*/
171
172/*
173 * ex: set ts=8 sts=4 sw=4 et:
174 */
175