db791db4e1
CSiphash is a first class citizen, it's fine to use everwhere where we need it. NMHash wraps CSiphash and provides three things: 1) Convenience macros that make hashing nicer to use. 2) it uses a randomly generated, per-run hash seed, that can be combined with a guint static seed. 3) it's a general API for hashing data. It nowhere promises that it actually uses siphash24, although currently it does everywhere. NMHash is not (officially) siphash24. Add API nm_hash_siphash42_init() and nm_hash_siphash42() to "nm-hash-utils.h", that exposes (2) for use with regular CSiphash. You of course no longer get the convenice macros (1) but you get plain siphash24 (which NMHash does not give (3)). While at it, also add a nm_hash_complete_u64(). Usually, for hasing we want guint types. But we don't need to hide the fact, that the underlying value is first uint64. Expose it.
288 lines
13 KiB
C
288 lines
13 KiB
C
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
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/* NetworkManager -- Network link manager
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301 USA.
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*
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* (C) Copyright 2017 Red Hat, Inc.
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*/
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#ifndef __NM_HASH_UTILS_H__
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#define __NM_HASH_UTILS_H__
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#include "c-siphash/src/c-siphash.h"
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#include "nm-macros-internal.h"
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/*****************************************************************************/
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void nm_hash_siphash42_init (CSipHash *h, guint static_seed);
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/* Siphash24 of binary buffer @arr and @len, using the randomized seed from
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* other NMHash functions.
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*
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* Note, that this is guaranteed to use siphash42 under the hood (contrary to
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* all other NMHash API, which leave this undefined). That matters at the point,
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* where the caller needs to be sure that a reasonably strong hasing algorithm
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* is used. (Yes, NMHash is all about siphash24, but otherwise that is not promised
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* anywhere).
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*
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* Another difference is, that this returns guint64 (not guint like other NMHash functions).
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*
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* Another difference is, that this may also return zero (not like nm_hash_complete()).
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*
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* Then, why not use c_siphash_hash() directly? Because this also uses the randomized,
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* per-run hash-seed like nm_hash_init(). So, you get siphash24 with a random
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* seed (which is cached for the current run of the program).
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*/
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static inline guint64
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nm_hash_siphash42 (guint static_seed, const void *ptr, gsize n)
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{
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CSipHash h;
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nm_hash_siphash42_init (&h, static_seed);
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c_siphash_append (&h, ptr, n);
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return c_siphash_finalize (&h);
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}
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/*****************************************************************************/
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struct _NMHashState {
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CSipHash _state;
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};
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typedef struct _NMHashState NMHashState;
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guint nm_hash_static (guint static_seed);
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static inline void
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nm_hash_init (NMHashState *state, guint static_seed)
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{
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nm_assert (state);
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nm_hash_siphash42_init (&state->_state, static_seed);
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}
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static inline guint64
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nm_hash_complete_u64 (NMHashState *state)
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{
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nm_assert (state);
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/* this returns the native u64 hash value. Note that this differs
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* from nm_hash_complete() in two ways:
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*
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* - the type, guint64 vs. guint.
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* - nm_hash_complete() never returns zero. */
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return c_siphash_finalize (&state->_state);
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}
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static inline guint
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nm_hash_complete (NMHashState *state)
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{
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guint64 h;
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h = nm_hash_complete_u64 (state);
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/* we don't ever want to return a zero hash.
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*
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* NMPObject requires that in _idx_obj_part(), and it's just a good idea. */
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return (((guint) (h >> 32)) ^ ((guint) h)) ?: 1396707757u;
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}
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static inline void
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nm_hash_update (NMHashState *state, const void *ptr, gsize n)
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{
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nm_assert (state);
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nm_assert (ptr);
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nm_assert (n > 0);
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/* Note: the data passed in here might be sensitive data (secrets),
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* that we should nm_explicty_zero() afterwards. However, since
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* we are using siphash24 with a random key, that is not really
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* necessary. Something to keep in mind, if we ever move away from
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* this hash implementation. */
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c_siphash_append (&state->_state, ptr, n);
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}
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#define nm_hash_update_val(state, val) \
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G_STMT_START { \
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typeof (val) _val = (val); \
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\
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nm_hash_update ((state), &_val, sizeof (_val)); \
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} G_STMT_END
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static inline void
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nm_hash_update_bool (NMHashState *state, bool val)
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{
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nm_hash_update (state, &val, sizeof (val));
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}
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#define _NM_HASH_COMBINE_BOOLS_x_1( t, y) ((y) ? ((t) (1ull << 0)) : ((t) 0ull))
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#define _NM_HASH_COMBINE_BOOLS_x_2( t, y, ...) ((y) ? ((t) (1ull << 1)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_1 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_3( t, y, ...) ((y) ? ((t) (1ull << 2)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_2 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_4( t, y, ...) ((y) ? ((t) (1ull << 3)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_3 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_5( t, y, ...) ((y) ? ((t) (1ull << 4)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_4 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_6( t, y, ...) ((y) ? ((t) (1ull << 5)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_5 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_7( t, y, ...) ((y) ? ((t) (1ull << 6)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_6 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_8( t, y, ...) ((y) ? ((t) (1ull << 7)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_7 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_9( t, y, ...) ((y) ? ((t) (1ull << 8)) : ((t) 0ull)) | (G_STATIC_ASSERT_EXPR (sizeof (t) >= 2), (_NM_HASH_COMBINE_BOOLS_x_8 (t, __VA_ARGS__)))
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#define _NM_HASH_COMBINE_BOOLS_x_10(t, y, ...) ((y) ? ((t) (1ull << 9)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_9 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_x_11(t, y, ...) ((y) ? ((t) (1ull << 10)) : ((t) 0ull)) | _NM_HASH_COMBINE_BOOLS_x_10 (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_n2(t, n, ...) _NM_HASH_COMBINE_BOOLS_x_##n (t, __VA_ARGS__)
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#define _NM_HASH_COMBINE_BOOLS_n(t, n, ...) _NM_HASH_COMBINE_BOOLS_n2(t, n, __VA_ARGS__)
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#define NM_HASH_COMBINE_BOOLS(type, ...) ((type) (_NM_HASH_COMBINE_BOOLS_n(type, NM_NARG (__VA_ARGS__), __VA_ARGS__)))
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#define nm_hash_update_bools(state, ...) \
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nm_hash_update_val (state, NM_HASH_COMBINE_BOOLS (guint8, __VA_ARGS__))
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#define _NM_HASH_COMBINE_VALS_typ_x_1( y) typeof (y) _v1;
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#define _NM_HASH_COMBINE_VALS_typ_x_2( y, ...) typeof (y) _v2; _NM_HASH_COMBINE_VALS_typ_x_1 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_3( y, ...) typeof (y) _v3; _NM_HASH_COMBINE_VALS_typ_x_2 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_4( y, ...) typeof (y) _v4; _NM_HASH_COMBINE_VALS_typ_x_3 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_5( y, ...) typeof (y) _v5; _NM_HASH_COMBINE_VALS_typ_x_4 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_6( y, ...) typeof (y) _v6; _NM_HASH_COMBINE_VALS_typ_x_5 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_7( y, ...) typeof (y) _v7; _NM_HASH_COMBINE_VALS_typ_x_6 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_8( y, ...) typeof (y) _v8; _NM_HASH_COMBINE_VALS_typ_x_7 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_9( y, ...) typeof (y) _v9; _NM_HASH_COMBINE_VALS_typ_x_8 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_10(y, ...) typeof (y) _v10; _NM_HASH_COMBINE_VALS_typ_x_9 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_11(y, ...) typeof (y) _v11; _NM_HASH_COMBINE_VALS_typ_x_10 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_12(y, ...) typeof (y) _v12; _NM_HASH_COMBINE_VALS_typ_x_11 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_13(y, ...) typeof (y) _v13; _NM_HASH_COMBINE_VALS_typ_x_12 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_14(y, ...) typeof (y) _v14; _NM_HASH_COMBINE_VALS_typ_x_13 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_15(y, ...) typeof (y) _v15; _NM_HASH_COMBINE_VALS_typ_x_14 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_16(y, ...) typeof (y) _v16; _NM_HASH_COMBINE_VALS_typ_x_15 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_17(y, ...) typeof (y) _v17; _NM_HASH_COMBINE_VALS_typ_x_16 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_18(y, ...) typeof (y) _v18; _NM_HASH_COMBINE_VALS_typ_x_17 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_19(y, ...) typeof (y) _v19; _NM_HASH_COMBINE_VALS_typ_x_18 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_x_20(y, ...) typeof (y) _v20; _NM_HASH_COMBINE_VALS_typ_x_19 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_n2(n, ...) _NM_HASH_COMBINE_VALS_typ_x_##n (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_typ_n(n, ...) _NM_HASH_COMBINE_VALS_typ_n2(n, __VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_1( y) ._v1 = (y),
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#define _NM_HASH_COMBINE_VALS_val_x_2( y, ...) ._v2 = (y), _NM_HASH_COMBINE_VALS_val_x_1 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_3( y, ...) ._v3 = (y), _NM_HASH_COMBINE_VALS_val_x_2 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_4( y, ...) ._v4 = (y), _NM_HASH_COMBINE_VALS_val_x_3 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_5( y, ...) ._v5 = (y), _NM_HASH_COMBINE_VALS_val_x_4 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_6( y, ...) ._v6 = (y), _NM_HASH_COMBINE_VALS_val_x_5 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_7( y, ...) ._v7 = (y), _NM_HASH_COMBINE_VALS_val_x_6 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_8( y, ...) ._v8 = (y), _NM_HASH_COMBINE_VALS_val_x_7 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_9( y, ...) ._v9 = (y), _NM_HASH_COMBINE_VALS_val_x_8 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_10(y, ...) ._v10 = (y), _NM_HASH_COMBINE_VALS_val_x_9 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_11(y, ...) ._v11 = (y), _NM_HASH_COMBINE_VALS_val_x_10 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_12(y, ...) ._v12 = (y), _NM_HASH_COMBINE_VALS_val_x_11 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_13(y, ...) ._v13 = (y), _NM_HASH_COMBINE_VALS_val_x_12 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_14(y, ...) ._v14 = (y), _NM_HASH_COMBINE_VALS_val_x_13 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_15(y, ...) ._v15 = (y), _NM_HASH_COMBINE_VALS_val_x_14 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_16(y, ...) ._v16 = (y), _NM_HASH_COMBINE_VALS_val_x_15 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_17(y, ...) ._v17 = (y), _NM_HASH_COMBINE_VALS_val_x_16 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_18(y, ...) ._v18 = (y), _NM_HASH_COMBINE_VALS_val_x_17 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_19(y, ...) ._v19 = (y), _NM_HASH_COMBINE_VALS_val_x_18 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_x_20(y, ...) ._v20 = (y), _NM_HASH_COMBINE_VALS_val_x_19 (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_n2(n, ...) _NM_HASH_COMBINE_VALS_val_x_##n (__VA_ARGS__)
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#define _NM_HASH_COMBINE_VALS_val_n(n, ...) _NM_HASH_COMBINE_VALS_val_n2(n, __VA_ARGS__)
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/* NM_HASH_COMBINE_VALS() is faster then nm_hash_update_val() as it combines multiple
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* calls to nm_hash_update() using a packed structure. */
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#define NM_HASH_COMBINE_VALS(var, ...) \
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const struct _nm_packed { \
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_NM_HASH_COMBINE_VALS_typ_n (NM_NARG (__VA_ARGS__), __VA_ARGS__) \
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} var _nm_alignas (guint64) = { \
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_NM_HASH_COMBINE_VALS_val_n (NM_NARG (__VA_ARGS__), __VA_ARGS__) \
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}
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/* nm_hash_update_vals() is faster then nm_hash_update_val() as it combines multiple
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* calls to nm_hash_update() using a packed structure. */
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#define nm_hash_update_vals(state, ...) \
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G_STMT_START { \
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NM_HASH_COMBINE_VALS (_val, __VA_ARGS__); \
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\
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nm_hash_update ((state), &_val, sizeof (_val)); \
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} G_STMT_END
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static inline void
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nm_hash_update_mem (NMHashState *state, const void *ptr, gsize n)
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{
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/* This also hashes the length of the data. That means,
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* hashing two consecutive binary fields (of arbitrary
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* length), will hash differently. That is,
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* [[1,1], []] differs from [[1],[1]].
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*
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* If you have a constant length (sizeof), use nm_hash_update()
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* instead. */
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nm_hash_update (state, &n, sizeof (n));
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if (n > 0)
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nm_hash_update (state, ptr, n);
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}
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static inline void
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nm_hash_update_str0 (NMHashState *state, const char *str)
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{
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if (str)
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nm_hash_update_mem (state, str, strlen (str));
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else {
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gsize n = G_MAXSIZE;
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nm_hash_update (state, &n, sizeof (n));
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}
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}
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static inline void
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nm_hash_update_str (NMHashState *state, const char *str)
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{
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nm_assert (str);
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nm_hash_update (state, str, strlen (str) + 1);
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}
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#if _NM_CC_SUPPORT_GENERIC
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/* Like nm_hash_update_str(), but restricted to arrays only. nm_hash_update_str() only works
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* with a @str argument that cannot be NULL. If you have a string pointer, that is never NULL, use
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* nm_hash_update() instead. */
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#define nm_hash_update_strarr(state, str) \
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(_Generic (&(str), \
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const char (*) [sizeof (str)]: nm_hash_update_str ((state), (str)), \
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char (*) [sizeof (str)]: nm_hash_update_str ((state), (str))) \
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)
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#else
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#define nm_hash_update_strarr(state, str) nm_hash_update_str ((state), (str))
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#endif
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guint nm_hash_ptr (gconstpointer ptr);
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guint nm_direct_hash (gconstpointer str);
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guint nm_hash_str (const char *str);
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guint nm_str_hash (gconstpointer str);
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#define nm_hash_val(static_seed, val) \
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({ \
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NMHashState _h; \
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\
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nm_hash_init (&_h, (static_seed)); \
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nm_hash_update_val (&_h, (val)); \
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nm_hash_complete (&_h); \
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})
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/*****************************************************************************/
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/* nm_pstr_*() are for hashing keys that are pointers to strings,
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* that is, "const char *const*" types, using strcmp(). */
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guint nm_pstr_hash (gconstpointer p);
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gboolean nm_pstr_equal (gconstpointer a, gconstpointer b);
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/*****************************************************************************/
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#endif /* __NM_HASH_UTILS_H__ */
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