1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2013 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
23 #include "siphash24.h"
24 #include "bus-bloom.h"
26 static inline void set_bit(uint64_t filter[], unsigned long b) {
27 filter[b >> 6] |= 1ULL << (b & 63);
30 static const sd_id128_t hash_keys[] = {
31 SD_ID128_ARRAY(b9,66,0b,f0,46,70,47,c1,88,75,c4,9c,54,b9,bd,15),
32 SD_ID128_ARRAY(aa,a1,54,a2,e0,71,4b,39,bf,e1,dd,2e,9f,c5,4a,3b),
33 SD_ID128_ARRAY(63,fd,ae,be,cd,82,48,12,a1,6e,41,26,cb,fa,a0,c8),
34 SD_ID128_ARRAY(23,be,45,29,32,d2,46,2d,82,03,52,28,fe,37,17,f5),
35 SD_ID128_ARRAY(56,3b,bf,ee,5a,4f,43,39,af,aa,94,08,df,f0,fc,10),
36 SD_ID128_ARRAY(31,80,c8,73,c7,ea,46,d3,aa,25,75,0f,9e,4c,09,29),
37 SD_ID128_ARRAY(7d,f7,18,4b,7b,a4,44,d5,85,3c,06,e0,65,53,96,6d),
38 SD_ID128_ARRAY(f2,77,e9,6f,93,b5,4e,71,9a,0c,34,88,39,25,bf,35),
41 static void bloom_add_data(
42 uint64_t filter[], /* The filter bits */
43 size_t size, /* Size of the filter in bytes */
44 unsigned k, /* Number of hash functions */
45 const void *data, /* Data to hash */
46 size_t n) { /* Size of data to hash in bytes */
55 /* Determine bits in filter */
58 /* Determine how many bytes we need to generate a bit index 0..m for this filter */
59 w = (u64log2(m) + 7) / 8;
61 assert(w <= sizeof(uint64_t));
63 /* Make sure we have enough hash keys to generate m * k bits
64 * of hash value. Note that SipHash24 generates 64 bits of
65 * hash value for each 128 bits of hash key. */
66 assert(k * w <= ELEMENTSOF(hash_keys) * 8);
68 for (i = 0; i < k; i++) {
72 for (d = 0; d < w; d++) {
74 siphash24(h, data, n, hash_keys[i++].bytes);
78 p = (p << 8ULL) | (uint64_t) h[8 - c];
86 /* log_debug("bloom: adding <%.*s>", (int) n, (char*) data); */
89 void bloom_add_pair(uint64_t filter[], size_t size, unsigned k, const char *a, const char *b) {
97 n = strlen(a) + 1 + strlen(b);
99 strcpy(stpcpy(stpcpy(c, a), ":"), b);
101 bloom_add_data(filter, size, k, c, n);
104 void bloom_add_prefixes(uint64_t filter[], size_t size, unsigned k, const char *a, const char *b, char sep) {
112 n = strlen(a) + 1 + strlen(b);
115 p = stpcpy(stpcpy(c, a), ":");
126 bloom_add_data(filter, size, k, c, e - c);
130 bool bloom_validate_parameters(size_t size, unsigned k) {
141 w = (u64log2(m) + 7) / 8;
142 if (w > sizeof(uint64_t))
145 if (k * w > ELEMENTSOF(hash_keys) * 8)