Commit | Line | Data |
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b423e985 | 1 | /* |
8ea4199d | 2 | * Copyright (c) 1985 Regents of the University of California. |
6b2f9dd0 KB |
3 | * All rights reserved. |
4 | * | |
5 | * Redistribution and use in source and binary forms are permitted | |
f4f66d2c KB |
6 | * provided that the above copyright notice and this paragraph are |
7 | * duplicated in all such forms and that any documentation, | |
8 | * advertising materials, and other materials related to such | |
9 | * distribution and use acknowledge that the software was developed | |
10 | * by the University of California, Berkeley. The name of the | |
11 | * University may not be used to endorse or promote products derived | |
12 | * from this software without specific prior written permission. | |
13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
15 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
b423e985 RC |
16 | */ |
17 | ||
2ce81398 | 18 | #if defined(LIBC_SCCS) && !defined(lint) |
f4f66d2c | 19 | static char sccsid[] = "@(#)res_comp.c 6.14 (Berkeley) %G%"; |
6b2f9dd0 | 20 | #endif /* LIBC_SCCS and not lint */ |
8ea4199d | 21 | |
fbc82d3e RC |
22 | #include <sys/types.h> |
23 | #include <stdio.h> | |
aa45ab0f | 24 | #include <arpa/nameser.h> |
fbc82d3e | 25 | |
fbc82d3e | 26 | /* |
36534519 | 27 | * Expand compressed domain name 'comp_dn' to full domain name. |
36534519 | 28 | * 'msg' is a pointer to the begining of the message, |
127b68cb | 29 | * 'eomorig' points to the first location after the message, |
36534519 | 30 | * 'exp_dn' is a pointer to a buffer of size 'length' for the result. |
fbc82d3e RC |
31 | * Return size of compressed name or -1 if there was an error. |
32 | */ | |
127b68cb | 33 | dn_expand(msg, eomorig, comp_dn, exp_dn, length) |
34082ede | 34 | u_char *msg, *eomorig, *comp_dn, *exp_dn; |
127b68cb | 35 | int length; |
fbc82d3e | 36 | { |
34082ede | 37 | register u_char *cp, *dn; |
fbc82d3e | 38 | register int n, c; |
34082ede | 39 | u_char *eom; |
19f533a7 | 40 | int len = -1, checked = 0; |
fbc82d3e RC |
41 | |
42 | dn = exp_dn; | |
43 | cp = comp_dn; | |
44 | eom = exp_dn + length - 1; | |
45 | /* | |
46 | * fetch next label in domain name | |
47 | */ | |
48 | while (n = *cp++) { | |
49 | /* | |
50 | * Check for indirection | |
51 | */ | |
52 | switch (n & INDIR_MASK) { | |
53 | case 0: | |
36534519 RC |
54 | if (dn != exp_dn) { |
55 | if (dn >= eom) | |
56 | return (-1); | |
fbc82d3e | 57 | *dn++ = '.'; |
36534519 | 58 | } |
fbc82d3e RC |
59 | if (dn+n >= eom) |
60 | return (-1); | |
19f533a7 | 61 | checked += n + 1; |
91c656a0 | 62 | while (--n >= 0) { |
80f420a7 JB |
63 | if ((c = *cp++) == '.') { |
64 | if (dn+n+1 >= eom) | |
65 | return (-1); | |
66 | *dn++ = '\\'; | |
36534519 | 67 | } |
80f420a7 | 68 | *dn++ = c; |
127b68cb | 69 | if (cp >= eomorig) /* out of range */ |
91c656a0 KD |
70 | return(-1); |
71 | } | |
fbc82d3e RC |
72 | break; |
73 | ||
74 | case INDIR_MASK: | |
36534519 | 75 | if (len < 0) |
fbc82d3e RC |
76 | len = cp - comp_dn + 1; |
77 | cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff)); | |
127b68cb | 78 | if (cp < msg || cp >= eomorig) /* out of range */ |
91c656a0 | 79 | return(-1); |
19f533a7 MK |
80 | checked += 2; |
81 | /* | |
82 | * Check for loops in the compressed name; | |
83 | * if we've looked at the whole message, | |
84 | * there must be a loop. | |
85 | */ | |
86 | if (checked >= eomorig - msg) | |
87 | return (-1); | |
fbc82d3e RC |
88 | break; |
89 | ||
90 | default: | |
91 | return (-1); /* flag error */ | |
92 | } | |
93 | } | |
94 | *dn = '\0'; | |
36534519 | 95 | if (len < 0) |
fbc82d3e RC |
96 | len = cp - comp_dn; |
97 | return (len); | |
98 | } | |
99 | ||
100 | /* | |
36534519 RC |
101 | * Compress domain name 'exp_dn' into 'comp_dn'. |
102 | * Return the size of the compressed name or -1. | |
103 | * 'length' is the size of the array pointed to by 'comp_dn'. | |
104 | * 'dnptrs' is a list of pointers to previous compressed names. dnptrs[0] | |
fbc82d3e | 105 | * is a pointer to the beginning of the message. The list ends with NULL. |
36534519 RC |
106 | * 'lastdnptr' is a pointer to the end of the arrary pointed to |
107 | * by 'dnptrs'. Side effect is to update the list of pointers for | |
108 | * labels inserted into the message as we compress the name. | |
109 | * If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr' | |
110 | * is NULL, we don't update the list. | |
fbc82d3e RC |
111 | */ |
112 | dn_comp(exp_dn, comp_dn, length, dnptrs, lastdnptr) | |
34082ede | 113 | u_char *exp_dn, *comp_dn; |
fbc82d3e | 114 | int length; |
34082ede | 115 | u_char **dnptrs, **lastdnptr; |
fbc82d3e | 116 | { |
34082ede | 117 | register u_char *cp, *dn; |
fbc82d3e | 118 | register int c, l; |
34082ede MK |
119 | u_char **cpp, **lpp, *sp, *eob; |
120 | u_char *msg; | |
fbc82d3e RC |
121 | |
122 | dn = exp_dn; | |
123 | cp = comp_dn; | |
a34de0ef | 124 | eob = cp + length; |
fbc82d3e RC |
125 | if (dnptrs != NULL) { |
126 | if ((msg = *dnptrs++) != NULL) { | |
127 | for (cpp = dnptrs; *cpp != NULL; cpp++) | |
128 | ; | |
129 | lpp = cpp; /* end of list to search */ | |
130 | } | |
131 | } else | |
132 | msg = NULL; | |
133 | for (c = *dn++; c != '\0'; ) { | |
134 | /* look to see if we can use pointers */ | |
135 | if (msg != NULL) { | |
136 | if ((l = dn_find(dn-1, msg, dnptrs, lpp)) >= 0) { | |
137 | if (cp+1 >= eob) | |
138 | return (-1); | |
139 | *cp++ = (l >> 8) | INDIR_MASK; | |
659c2773 | 140 | *cp++ = l % 256; |
fbc82d3e RC |
141 | return (cp - comp_dn); |
142 | } | |
143 | /* not found, save it */ | |
144 | if (lastdnptr != NULL && cpp < lastdnptr-1) { | |
145 | *cpp++ = cp; | |
146 | *cpp = NULL; | |
147 | } | |
148 | } | |
149 | sp = cp++; /* save ptr to length byte */ | |
150 | do { | |
151 | if (c == '.') { | |
152 | c = *dn++; | |
153 | break; | |
154 | } | |
36534519 RC |
155 | if (c == '\\') { |
156 | if ((c = *dn++) == '\0') | |
157 | break; | |
158 | } | |
fbc82d3e RC |
159 | if (cp >= eob) |
160 | return (-1); | |
161 | *cp++ = c; | |
162 | } while ((c = *dn++) != '\0'); | |
36534519 RC |
163 | /* catch trailing '.'s but not '..' */ |
164 | if ((l = cp - sp - 1) == 0 && c == '\0') { | |
165 | cp--; | |
166 | break; | |
167 | } | |
168 | if (l <= 0 || l > MAXLABEL) | |
fbc82d3e RC |
169 | return (-1); |
170 | *sp = l; | |
171 | } | |
172 | if (cp >= eob) | |
173 | return (-1); | |
174 | *cp++ = '\0'; | |
175 | return (cp - comp_dn); | |
176 | } | |
177 | ||
178 | /* | |
36534519 | 179 | * Skip over a compressed domain name. Return the size or -1. |
fbc82d3e | 180 | */ |
34082ede MK |
181 | dn_skipname(comp_dn, eom) |
182 | u_char *comp_dn, *eom; | |
fbc82d3e | 183 | { |
34082ede | 184 | register u_char *cp; |
fbc82d3e RC |
185 | register int n; |
186 | ||
36534519 | 187 | cp = comp_dn; |
34082ede | 188 | while (cp < eom && (n = *cp++)) { |
fbc82d3e RC |
189 | /* |
190 | * check for indirection | |
191 | */ | |
192 | switch (n & INDIR_MASK) { | |
193 | case 0: /* normal case, n == len */ | |
194 | cp += n; | |
195 | continue; | |
196 | default: /* illegal type */ | |
197 | return (-1); | |
198 | case INDIR_MASK: /* indirection */ | |
199 | cp++; | |
200 | } | |
201 | break; | |
202 | } | |
36534519 | 203 | return (cp - comp_dn); |
fbc82d3e RC |
204 | } |
205 | ||
206 | /* | |
207 | * Search for expanded name from a list of previously compressed names. | |
208 | * Return the offset from msg if found or -1. | |
3182644d MK |
209 | * dnptrs is the pointer to the first name on the list, |
210 | * not the pointer to the start of the message. | |
fbc82d3e | 211 | */ |
3182644d | 212 | static |
fbc82d3e | 213 | dn_find(exp_dn, msg, dnptrs, lastdnptr) |
34082ede MK |
214 | u_char *exp_dn, *msg; |
215 | u_char **dnptrs, **lastdnptr; | |
fbc82d3e | 216 | { |
34082ede | 217 | register u_char *dn, *cp, **cpp; |
fbc82d3e | 218 | register int n; |
34082ede | 219 | u_char *sp; |
fbc82d3e | 220 | |
3182644d | 221 | for (cpp = dnptrs; cpp < lastdnptr; cpp++) { |
fbc82d3e RC |
222 | dn = exp_dn; |
223 | sp = cp = *cpp; | |
224 | while (n = *cp++) { | |
225 | /* | |
226 | * check for indirection | |
227 | */ | |
228 | switch (n & INDIR_MASK) { | |
229 | case 0: /* normal case, n == len */ | |
36534519 RC |
230 | while (--n >= 0) { |
231 | if (*dn == '\\') | |
232 | dn++; | |
fbc82d3e RC |
233 | if (*dn++ != *cp++) |
234 | goto next; | |
36534519 | 235 | } |
fbc82d3e RC |
236 | if ((n = *dn++) == '\0' && *cp == '\0') |
237 | return (sp - msg); | |
238 | if (n == '.') | |
239 | continue; | |
240 | goto next; | |
241 | ||
242 | default: /* illegal type */ | |
243 | return (-1); | |
244 | ||
245 | case INDIR_MASK: /* indirection */ | |
34082ede | 246 | cp = msg + (((n & 0x3f) << 8) | *cp); |
fbc82d3e RC |
247 | } |
248 | } | |
249 | if (*dn == '\0') | |
250 | return (sp - msg); | |
251 | next: ; | |
252 | } | |
253 | return (-1); | |
254 | } | |
11e57e73 RC |
255 | |
256 | /* | |
257 | * Routines to insert/extract short/long's. Must account for byte | |
258 | * order and non-alignment problems. This code at least has the | |
259 | * advantage of being portable. | |
414b2e0c KB |
260 | * |
261 | * used by sendmail. | |
11e57e73 RC |
262 | */ |
263 | ||
264 | u_short | |
20087cad | 265 | _getshort(msgp) |
34082ede | 266 | u_char *msgp; |
11e57e73 RC |
267 | { |
268 | register u_char *p = (u_char *) msgp; | |
a34de0ef JB |
269 | #ifdef vax |
270 | /* | |
271 | * vax compiler doesn't put shorts in registers | |
272 | */ | |
273 | register u_long u; | |
274 | #else | |
27a3141f | 275 | register u_short u; |
a34de0ef | 276 | #endif |
11e57e73 | 277 | |
27a3141f | 278 | u = *p++ << 8; |
a34de0ef | 279 | return ((u_short)(u | *p)); |
11e57e73 RC |
280 | } |
281 | ||
282 | u_long | |
20087cad | 283 | _getlong(msgp) |
34082ede | 284 | u_char *msgp; |
11e57e73 RC |
285 | { |
286 | register u_char *p = (u_char *) msgp; | |
577f64e7 | 287 | register u_long u; |
11e57e73 | 288 | |
577f64e7 KD |
289 | u = *p++; u <<= 8; |
290 | u |= *p++; u <<= 8; | |
291 | u |= *p++; u <<= 8; | |
292 | return (u | *p); | |
11e57e73 RC |
293 | } |
294 | ||
577f64e7 | 295 | |
11e57e73 RC |
296 | putshort(s, msgp) |
297 | register u_short s; | |
34082ede | 298 | register u_char *msgp; |
11e57e73 RC |
299 | { |
300 | ||
301 | msgp[1] = s; | |
302 | msgp[0] = s >> 8; | |
303 | } | |
304 | ||
11e57e73 RC |
305 | putlong(l, msgp) |
306 | register u_long l; | |
34082ede | 307 | register u_char *msgp; |
11e57e73 RC |
308 | { |
309 | ||
310 | msgp[3] = l; | |
311 | msgp[2] = (l >>= 8); | |
312 | msgp[1] = (l >>= 8); | |
313 | msgp[0] = l >> 8; | |
314 | } |