1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
/* $OpenBSD: hash.c,v 1.2 2004/04/14 00:56:02 henning Exp $ */
/* Routines for manipulating hash tables... */
/*
* Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of The Internet Software Consortium nor the names
* of its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This software has been written for the Internet Software Consortium
* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
* Enterprises. To learn more about the Internet Software Consortium,
* see ``http://www.vix.com/isc''. To learn more about Vixie
* Enterprises, see ``http://www.vix.com''.
*/
#include "dhcpd.h"
static int do_hash(unsigned char *, int, int);
struct hash_table *
new_hash(void)
{
struct hash_table *rv = new_hash_table(DEFAULT_HASH_SIZE, "new_hash");
if (!rv)
return (rv);
memset(&rv->buckets[0], 0,
DEFAULT_HASH_SIZE * sizeof(struct hash_bucket *));
return (rv);
}
static int
do_hash(unsigned char *name, int len, int size)
{
int accum = 0;
unsigned char *s = name;
int i = len;
while (i--) {
/* Add the character in... */
accum += *s++;
/* Add carry back in... */
while (accum > 255)
accum = (accum & 255) + (accum >> 8);
}
return (accum % size);
}
void add_hash(struct hash_table *table, unsigned char *name, int len,
unsigned char *pointer)
{
int hashno;
struct hash_bucket *bp;
if (!table)
return;
if (!len)
len = strlen((char *)name);
hashno = do_hash(name, len, table->hash_count);
bp = new_hash_bucket("add_hash");
if (!bp) {
warn("Can't add %s to hash table.", name);
return;
}
bp->name = name;
bp->value = pointer;
bp->next = table->buckets[hashno];
bp->len = len;
table->buckets[hashno] = bp;
}
void
delete_hash_entry(struct hash_table *table, unsigned char *name, int len)
{
int hashno;
struct hash_bucket *bp, *pbp = NULL;
if (!table)
return;
if (!len)
len = strlen((char *)name);
hashno = do_hash(name, len, table->hash_count);
/*
* Go through the list looking for an entry that matches; if we
* find it, delete it.
*/
for (bp = table->buckets[hashno]; bp; bp = bp->next) {
if ((!bp->len &&
!strcmp((char *)bp->name, (char *)name)) ||
(bp->len == len && !memcmp(bp->name, name, len))) {
if (pbp)
pbp->next = bp->next;
else
table->buckets[hashno] = bp->next;
free_hash_bucket(bp, "delete_hash_entry");
break;
}
pbp = bp; /* jwg, 9/6/96 - nice catch! */
}
}
unsigned char *
hash_lookup(struct hash_table *table, unsigned char *name, int len)
{
int hashno;
struct hash_bucket *bp;
if (!table)
return (NULL);
if (!len)
len = strlen((char *)name);
hashno = do_hash(name, len, table->hash_count);
for (bp = table->buckets[hashno]; bp; bp = bp->next)
if (len == bp->len && !memcmp(bp->name, name, len))
return (bp->value);
return (NULL);
}
|
