mirror of
https://gitlab.freedesktop.org/NetworkManager/NetworkManager.git
synced 2025-12-25 04:50:07 +01:00
0e9e35e309
The privious NM_HASH_* macros directly operated on a guint value and were thus close to the actual implementation. Replace them by adding a NMHashState struct and accessors to update the hash state. This hides the implementation better and would allow us to carry more state. For example, we could switch to siphash24() transparently. For now, we still do a form basically djb2 hashing, albeit with differing start seed. Also add nm_hash_str() and nm_str_hash(): - nm_hash_str() is our own string hashing implementation - nm_str_hash() is our own string implementation, but with a GHashFunc signature, suitable to pass it to g_hash_table_new(). Also, it has this name in order to remind you of g_str_hash(), which it is replacing.
75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
|
|
/* NetworkManager -- Network link manager
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the
|
|
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
|
|
* Boston, MA 02110-1301 USA.
|
|
*
|
|
* (C) Copyright 2017 Red Hat, Inc.
|
|
*/
|
|
|
|
#include "nm-default.h"
|
|
|
|
#include "nm-hash-utils.h"
|
|
|
|
#include "nm-shared-utils.h"
|
|
#include "nm-random-utils.h"
|
|
|
|
/*****************************************************************************/
|
|
|
|
void
|
|
nm_hash_init (NMHashState *state, guint static_seed)
|
|
{
|
|
static volatile guint global_seed = 0;
|
|
guint g, s;
|
|
|
|
nm_assert (state);
|
|
|
|
/* we xor @seed with a random @global_seed. This is to make the hashing behavior
|
|
* less predictable and harder to exploit collisions. */
|
|
g = global_seed;
|
|
if (G_UNLIKELY (g == 0)) {
|
|
nm_utils_random_bytes (&s, sizeof (s));
|
|
if (s == 0)
|
|
s = 42;
|
|
g_atomic_int_compare_and_exchange ((int *) &global_seed, 0, s);
|
|
g = global_seed;
|
|
nm_assert (g);
|
|
}
|
|
|
|
s = g ^ static_seed;
|
|
state->hash = s;
|
|
}
|
|
|
|
guint
|
|
nm_hash_str (const char *str)
|
|
{
|
|
NMHashState h;
|
|
|
|
nm_hash_init (&h, 1867854211u);
|
|
nm_hash_update_str (&h, str);
|
|
return nm_hash_complete (&h);
|
|
}
|
|
|
|
guint
|
|
nm_str_hash (gconstpointer str)
|
|
{
|
|
return nm_hash_str (str);
|
|
}
|
|
|
|
guint
|
|
nm_direct_hash (gconstpointer ptr)
|
|
{
|
|
return nm_hash_ptr (ptr);
|
|
}
|