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15637ed4 RG |
1 | /* |
2 | * Copyright (c) 1986 Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the University of | |
16 | * California, Berkeley and its contributors. | |
17 | * 4. Neither the name of the University nor the names of its contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | */ | |
33 | ||
34 | #ifndef lint | |
35 | static char sccsid[] = "@(#)db_lookup.c 4.18 (Berkeley) 3/21/91"; | |
36 | #endif /* not lint */ | |
37 | ||
38 | /* | |
39 | * Table lookup routines. | |
40 | */ | |
41 | ||
42 | #include <sys/param.h> | |
43 | #include <arpa/nameser.h> | |
44 | #include <stdio.h> | |
45 | #include "db.h" | |
46 | ||
47 | struct hashbuf *hashtab; /* root hash table */ | |
48 | struct hashbuf *fcachetab; /* hash table of cache read from file */ | |
49 | ||
50 | #ifdef DEBUG | |
51 | extern int debug; | |
52 | extern FILE *ddt; | |
53 | #endif | |
54 | ||
55 | /* | |
56 | * Lookup 'name' and return a pointer to the namebuf; | |
57 | * NULL otherwise. If 'insert', insert name into tables. | |
58 | * Wildcard lookups are handled. | |
59 | */ | |
60 | struct namebuf * | |
61 | nlookup(name, htpp, fname, insert) | |
62 | char *name; | |
63 | struct hashbuf **htpp; | |
64 | char **fname; | |
65 | int insert; | |
66 | { | |
67 | register struct namebuf *np; | |
68 | register char *cp; | |
69 | register int c; | |
70 | register unsigned hval; | |
71 | register struct hashbuf *htp; | |
72 | struct namebuf *parent = NULL; | |
73 | ||
74 | htp = *htpp; | |
75 | hval = 0; | |
76 | *fname = "???"; | |
77 | for (cp = name; c = *cp++; ) { | |
78 | if (c == '.') { | |
79 | parent = np = nlookup(cp, htpp, fname, insert); | |
80 | if (np == NULL) | |
81 | return (NULL); | |
82 | if (*fname != cp) | |
83 | return (np); | |
84 | if ((htp = np->n_hash) == NULL) { | |
85 | if (!insert) { | |
86 | if (np->n_dname[0] == '*' && | |
87 | np->n_dname[1] == '\0') | |
88 | *fname = name; | |
89 | return (np); | |
90 | } | |
91 | htp = savehash((struct hashbuf *)NULL); | |
92 | np->n_hash = htp; | |
93 | } | |
94 | *htpp = htp; | |
95 | break; | |
96 | } | |
97 | hval <<= HASHSHIFT; | |
98 | hval += c & HASHMASK; | |
99 | } | |
100 | c = *--cp; | |
101 | *cp = '\0'; | |
102 | /* | |
103 | * Lookup this label in current hash table. | |
104 | */ | |
105 | for (np = htp->h_tab[hval % htp->h_size]; np != NULL; np = np->n_next) { | |
106 | if (np->n_hashval == hval && | |
107 | strcasecmp(name, np->n_dname) == 0) { | |
108 | *cp = c; | |
109 | *fname = name; | |
110 | return (np); | |
111 | } | |
112 | } | |
113 | if (!insert) { | |
114 | /* | |
115 | * Look for wildcard in this hash table. | |
116 | * Don't use a cached "*" name as a wildcard, | |
117 | * only authoritative. | |
118 | */ | |
119 | hval = ('*' & HASHMASK) % htp->h_size; | |
120 | for (np = htp->h_tab[hval]; np != NULL; np = np->n_next) { | |
121 | if (np->n_dname[0] == '*' && np->n_dname[1] == '\0' && | |
122 | np->n_data && np->n_data->d_zone != 0) { | |
123 | *cp = c; | |
124 | *fname = name; | |
125 | return (np); | |
126 | } | |
127 | } | |
128 | *cp = c; | |
129 | return (parent); | |
130 | } | |
131 | np = savename(name); | |
132 | np->n_parent = parent; | |
133 | np->n_hashval = hval; | |
134 | hval %= htp->h_size; | |
135 | np->n_next = htp->h_tab[hval]; | |
136 | htp->h_tab[hval] = np; | |
137 | /* increase hash table size */ | |
138 | if (++htp->h_cnt > htp->h_size * 2) { | |
139 | *htpp = savehash(htp); | |
140 | if (parent == NULL) { | |
141 | if (htp == hashtab) | |
142 | hashtab = *htpp; | |
143 | else | |
144 | fcachetab = *htpp; | |
145 | } | |
146 | else | |
147 | parent->n_hash = *htpp; | |
148 | htp = *htpp; | |
149 | } | |
150 | *cp = c; | |
151 | *fname = name; | |
152 | return (np); | |
153 | } | |
154 | ||
155 | /* | |
156 | * Does the data record match the class and type? | |
157 | */ | |
158 | match(dp, class, type) | |
159 | register struct databuf *dp; | |
160 | register int class, type; | |
161 | { | |
162 | #ifdef DEBUG | |
163 | if (debug >= 5) | |
164 | fprintf(ddt,"match(0x%x, %d, %d) %d, %d\n", dp, class, type, | |
165 | dp->d_class, dp->d_type); | |
166 | #endif | |
167 | if (dp->d_class != class && class != C_ANY) | |
168 | return (0); | |
169 | if (dp->d_type != type && type != T_ANY) | |
170 | return (0); | |
171 | return (1); | |
172 | } |