Commit | Line | Data |
---|---|---|
b423e985 | 1 | /* |
8ea4199d DF |
2 | * Copyright (c) 1985 Regents of the University of California. |
3 | * All rights reserved. The Berkeley software License Agreement | |
4 | * specifies the terms and conditions for redistribution. | |
b423e985 RC |
5 | */ |
6 | ||
2ce81398 | 7 | #if defined(LIBC_SCCS) && !defined(lint) |
80f420a7 | 8 | static char sccsid[] = "@(#)res_comp.c 6.7 (Berkeley) %G%"; |
2ce81398 | 9 | #endif LIBC_SCCS and not lint |
8ea4199d | 10 | |
fbc82d3e RC |
11 | #include <sys/types.h> |
12 | #include <stdio.h> | |
aa45ab0f | 13 | #include <arpa/nameser.h> |
fbc82d3e | 14 | |
577f64e7 | 15 | |
fbc82d3e | 16 | /* |
36534519 | 17 | * Expand compressed domain name 'comp_dn' to full domain name. |
36534519 | 18 | * 'msg' is a pointer to the begining of the message, |
127b68cb | 19 | * 'eomorig' points to the first location after the message, |
36534519 | 20 | * 'exp_dn' is a pointer to a buffer of size 'length' for the result. |
fbc82d3e RC |
21 | * Return size of compressed name or -1 if there was an error. |
22 | */ | |
127b68cb MK |
23 | dn_expand(msg, eomorig, comp_dn, exp_dn, length) |
24 | char *msg, *eomorig, *comp_dn, *exp_dn; | |
25 | int length; | |
fbc82d3e RC |
26 | { |
27 | register char *cp, *dn; | |
28 | register int n, c; | |
127b68cb | 29 | char *eom; |
36534519 | 30 | int len = -1; |
fbc82d3e RC |
31 | |
32 | dn = exp_dn; | |
33 | cp = comp_dn; | |
34 | eom = exp_dn + length - 1; | |
35 | /* | |
36 | * fetch next label in domain name | |
37 | */ | |
38 | while (n = *cp++) { | |
39 | /* | |
40 | * Check for indirection | |
41 | */ | |
42 | switch (n & INDIR_MASK) { | |
43 | case 0: | |
36534519 RC |
44 | if (dn != exp_dn) { |
45 | if (dn >= eom) | |
46 | return (-1); | |
fbc82d3e | 47 | *dn++ = '.'; |
36534519 | 48 | } |
fbc82d3e RC |
49 | if (dn+n >= eom) |
50 | return (-1); | |
91c656a0 | 51 | while (--n >= 0) { |
80f420a7 JB |
52 | if ((c = *cp++) == '.') { |
53 | if (dn+n+1 >= eom) | |
54 | return (-1); | |
55 | *dn++ = '\\'; | |
36534519 | 56 | } |
80f420a7 | 57 | *dn++ = c; |
127b68cb | 58 | if (cp >= eomorig) /* out of range */ |
91c656a0 KD |
59 | return(-1); |
60 | } | |
fbc82d3e RC |
61 | break; |
62 | ||
63 | case INDIR_MASK: | |
36534519 | 64 | if (len < 0) |
fbc82d3e RC |
65 | len = cp - comp_dn + 1; |
66 | cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff)); | |
127b68cb | 67 | if (cp < msg || cp >= eomorig) /* out of range */ |
91c656a0 | 68 | return(-1); |
fbc82d3e RC |
69 | break; |
70 | ||
71 | default: | |
72 | return (-1); /* flag error */ | |
73 | } | |
74 | } | |
75 | *dn = '\0'; | |
36534519 | 76 | if (len < 0) |
fbc82d3e RC |
77 | len = cp - comp_dn; |
78 | return (len); | |
79 | } | |
80 | ||
81 | /* | |
36534519 RC |
82 | * Compress domain name 'exp_dn' into 'comp_dn'. |
83 | * Return the size of the compressed name or -1. | |
84 | * 'length' is the size of the array pointed to by 'comp_dn'. | |
85 | * 'dnptrs' is a list of pointers to previous compressed names. dnptrs[0] | |
fbc82d3e | 86 | * is a pointer to the beginning of the message. The list ends with NULL. |
36534519 RC |
87 | * 'lastdnptr' is a pointer to the end of the arrary pointed to |
88 | * by 'dnptrs'. Side effect is to update the list of pointers for | |
89 | * labels inserted into the message as we compress the name. | |
90 | * If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr' | |
91 | * is NULL, we don't update the list. | |
fbc82d3e RC |
92 | */ |
93 | dn_comp(exp_dn, comp_dn, length, dnptrs, lastdnptr) | |
94 | char *exp_dn, *comp_dn; | |
95 | int length; | |
96 | char **dnptrs, **lastdnptr; | |
97 | { | |
98 | register char *cp, *dn; | |
99 | register int c, l; | |
100 | char **cpp, **lpp, *sp, *eob; | |
101 | char *msg; | |
102 | ||
103 | dn = exp_dn; | |
104 | cp = comp_dn; | |
a34de0ef | 105 | eob = cp + length; |
fbc82d3e RC |
106 | if (dnptrs != NULL) { |
107 | if ((msg = *dnptrs++) != NULL) { | |
108 | for (cpp = dnptrs; *cpp != NULL; cpp++) | |
109 | ; | |
110 | lpp = cpp; /* end of list to search */ | |
111 | } | |
112 | } else | |
113 | msg = NULL; | |
114 | for (c = *dn++; c != '\0'; ) { | |
115 | /* look to see if we can use pointers */ | |
116 | if (msg != NULL) { | |
117 | if ((l = dn_find(dn-1, msg, dnptrs, lpp)) >= 0) { | |
118 | if (cp+1 >= eob) | |
119 | return (-1); | |
120 | *cp++ = (l >> 8) | INDIR_MASK; | |
659c2773 | 121 | *cp++ = l % 256; |
fbc82d3e RC |
122 | return (cp - comp_dn); |
123 | } | |
124 | /* not found, save it */ | |
125 | if (lastdnptr != NULL && cpp < lastdnptr-1) { | |
126 | *cpp++ = cp; | |
127 | *cpp = NULL; | |
128 | } | |
129 | } | |
130 | sp = cp++; /* save ptr to length byte */ | |
131 | do { | |
132 | if (c == '.') { | |
133 | c = *dn++; | |
134 | break; | |
135 | } | |
36534519 RC |
136 | if (c == '\\') { |
137 | if ((c = *dn++) == '\0') | |
138 | break; | |
139 | } | |
fbc82d3e RC |
140 | if (cp >= eob) |
141 | return (-1); | |
142 | *cp++ = c; | |
143 | } while ((c = *dn++) != '\0'); | |
36534519 RC |
144 | /* catch trailing '.'s but not '..' */ |
145 | if ((l = cp - sp - 1) == 0 && c == '\0') { | |
146 | cp--; | |
147 | break; | |
148 | } | |
149 | if (l <= 0 || l > MAXLABEL) | |
fbc82d3e RC |
150 | return (-1); |
151 | *sp = l; | |
152 | } | |
153 | if (cp >= eob) | |
154 | return (-1); | |
155 | *cp++ = '\0'; | |
156 | return (cp - comp_dn); | |
157 | } | |
158 | ||
159 | /* | |
36534519 | 160 | * Skip over a compressed domain name. Return the size or -1. |
fbc82d3e | 161 | */ |
36534519 RC |
162 | dn_skip(comp_dn) |
163 | char *comp_dn; | |
fbc82d3e RC |
164 | { |
165 | register char *cp; | |
166 | register int n; | |
167 | ||
36534519 | 168 | cp = comp_dn; |
fbc82d3e RC |
169 | while (n = *cp++) { |
170 | /* | |
171 | * check for indirection | |
172 | */ | |
173 | switch (n & INDIR_MASK) { | |
174 | case 0: /* normal case, n == len */ | |
175 | cp += n; | |
176 | continue; | |
177 | default: /* illegal type */ | |
178 | return (-1); | |
179 | case INDIR_MASK: /* indirection */ | |
180 | cp++; | |
181 | } | |
182 | break; | |
183 | } | |
36534519 | 184 | return (cp - comp_dn); |
fbc82d3e RC |
185 | } |
186 | ||
187 | /* | |
188 | * Search for expanded name from a list of previously compressed names. | |
189 | * Return the offset from msg if found or -1. | |
190 | */ | |
191 | dn_find(exp_dn, msg, dnptrs, lastdnptr) | |
192 | char *exp_dn, *msg; | |
193 | char **dnptrs, **lastdnptr; | |
194 | { | |
195 | register char *dn, *cp, **cpp; | |
196 | register int n; | |
197 | char *sp; | |
198 | ||
659c2773 | 199 | for (cpp = dnptrs + 1; cpp < lastdnptr; cpp++) { |
fbc82d3e RC |
200 | dn = exp_dn; |
201 | sp = cp = *cpp; | |
202 | while (n = *cp++) { | |
203 | /* | |
204 | * check for indirection | |
205 | */ | |
206 | switch (n & INDIR_MASK) { | |
207 | case 0: /* normal case, n == len */ | |
36534519 RC |
208 | while (--n >= 0) { |
209 | if (*dn == '\\') | |
210 | dn++; | |
fbc82d3e RC |
211 | if (*dn++ != *cp++) |
212 | goto next; | |
36534519 | 213 | } |
fbc82d3e RC |
214 | if ((n = *dn++) == '\0' && *cp == '\0') |
215 | return (sp - msg); | |
216 | if (n == '.') | |
217 | continue; | |
218 | goto next; | |
219 | ||
220 | default: /* illegal type */ | |
221 | return (-1); | |
222 | ||
223 | case INDIR_MASK: /* indirection */ | |
224 | cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff)); | |
225 | } | |
226 | } | |
227 | if (*dn == '\0') | |
228 | return (sp - msg); | |
229 | next: ; | |
230 | } | |
231 | return (-1); | |
232 | } | |
11e57e73 RC |
233 | |
234 | /* | |
235 | * Routines to insert/extract short/long's. Must account for byte | |
236 | * order and non-alignment problems. This code at least has the | |
237 | * advantage of being portable. | |
238 | */ | |
239 | ||
240 | u_short | |
241 | getshort(msgp) | |
242 | char *msgp; | |
243 | { | |
244 | register u_char *p = (u_char *) msgp; | |
a34de0ef JB |
245 | #ifdef vax |
246 | /* | |
247 | * vax compiler doesn't put shorts in registers | |
248 | */ | |
249 | register u_long u; | |
250 | #else | |
27a3141f | 251 | register u_short u; |
a34de0ef | 252 | #endif |
11e57e73 | 253 | |
27a3141f | 254 | u = *p++ << 8; |
a34de0ef | 255 | return ((u_short)(u | *p)); |
11e57e73 RC |
256 | } |
257 | ||
258 | u_long | |
259 | getlong(msgp) | |
260 | char *msgp; | |
261 | { | |
262 | register u_char *p = (u_char *) msgp; | |
577f64e7 | 263 | register u_long u; |
11e57e73 | 264 | |
577f64e7 KD |
265 | u = *p++; u <<= 8; |
266 | u |= *p++; u <<= 8; | |
267 | u |= *p++; u <<= 8; | |
268 | return (u | *p); | |
11e57e73 RC |
269 | } |
270 | ||
577f64e7 | 271 | |
11e57e73 RC |
272 | putshort(s, msgp) |
273 | register u_short s; | |
274 | register char *msgp; | |
275 | { | |
276 | ||
277 | msgp[1] = s; | |
278 | msgp[0] = s >> 8; | |
279 | } | |
280 | ||
11e57e73 RC |
281 | putlong(l, msgp) |
282 | register u_long l; | |
283 | register char *msgp; | |
284 | { | |
285 | ||
286 | msgp[3] = l; | |
287 | msgp[2] = (l >>= 8); | |
288 | msgp[1] = (l >>= 8); | |
289 | msgp[0] = l >> 8; | |
290 | } |