Commit | Line | Data |
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fbc82d3e | 1 | #ifndef lint |
b423e985 | 2 | static char sccsid[] = "@(#)res_comp.c 4.4 (Berkeley) %G%"; |
fbc82d3e RC |
3 | #endif |
4 | ||
b423e985 RC |
5 | /* |
6 | * Copyright (c) 1985 Regents of the University of California | |
7 | * All Rights Reserved | |
8 | */ | |
9 | ||
fbc82d3e RC |
10 | #include <sys/types.h> |
11 | #include <stdio.h> | |
12 | #include <ctype.h> | |
13 | #include <nameser.h> | |
14 | ||
fbc82d3e | 15 | /* |
36534519 RC |
16 | * Expand compressed domain name 'comp_dn' to full domain name. |
17 | * Expanded names are converted to upper case. | |
18 | * 'msg' is a pointer to the begining of the message, | |
19 | * 'exp_dn' is a pointer to a buffer of size 'length' for the result. | |
fbc82d3e RC |
20 | * Return size of compressed name or -1 if there was an error. |
21 | */ | |
22 | dn_expand(msg, comp_dn, exp_dn, length) | |
23 | char *msg, *comp_dn, *exp_dn; | |
24 | int length; | |
25 | { | |
26 | register char *cp, *dn; | |
27 | register int n, c; | |
28 | char *eom; | |
36534519 | 29 | int len = -1; |
fbc82d3e RC |
30 | |
31 | dn = exp_dn; | |
32 | cp = comp_dn; | |
33 | eom = exp_dn + length - 1; | |
34 | /* | |
35 | * fetch next label in domain name | |
36 | */ | |
37 | while (n = *cp++) { | |
38 | /* | |
39 | * Check for indirection | |
40 | */ | |
41 | switch (n & INDIR_MASK) { | |
42 | case 0: | |
36534519 RC |
43 | if (dn != exp_dn) { |
44 | if (dn >= eom) | |
45 | return (-1); | |
fbc82d3e | 46 | *dn++ = '.'; |
36534519 | 47 | } |
fbc82d3e RC |
48 | if (dn+n >= eom) |
49 | return (-1); | |
50 | while (--n >= 0) | |
51 | if (islower(c = *cp++)) | |
52 | *dn++ = toupper(c); | |
36534519 RC |
53 | else { |
54 | if (c == '.') { | |
55 | if (dn+n+1 >= eom) | |
56 | return (-1); | |
57 | *dn++ = '\\'; | |
58 | } | |
fbc82d3e | 59 | *dn++ = c; |
36534519 | 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)); | |
67 | break; | |
68 | ||
69 | default: | |
70 | return (-1); /* flag error */ | |
71 | } | |
72 | } | |
73 | *dn = '\0'; | |
36534519 | 74 | if (len < 0) |
fbc82d3e RC |
75 | len = cp - comp_dn; |
76 | return (len); | |
77 | } | |
78 | ||
79 | /* | |
36534519 RC |
80 | * Compress domain name 'exp_dn' into 'comp_dn'. |
81 | * Return the size of the compressed name or -1. | |
82 | * 'length' is the size of the array pointed to by 'comp_dn'. | |
83 | * 'dnptrs' is a list of pointers to previous compressed names. dnptrs[0] | |
fbc82d3e | 84 | * is a pointer to the beginning of the message. The list ends with NULL. |
36534519 RC |
85 | * 'lastdnptr' is a pointer to the end of the arrary pointed to |
86 | * by 'dnptrs'. Side effect is to update the list of pointers for | |
87 | * labels inserted into the message as we compress the name. | |
88 | * If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr' | |
89 | * is NULL, we don't update the list. | |
fbc82d3e RC |
90 | */ |
91 | dn_comp(exp_dn, comp_dn, length, dnptrs, lastdnptr) | |
92 | char *exp_dn, *comp_dn; | |
93 | int length; | |
94 | char **dnptrs, **lastdnptr; | |
95 | { | |
96 | register char *cp, *dn; | |
97 | register int c, l; | |
98 | char **cpp, **lpp, *sp, *eob; | |
99 | char *msg; | |
100 | ||
101 | dn = exp_dn; | |
102 | cp = comp_dn; | |
103 | eob = comp_dn + length; | |
104 | if (dnptrs != NULL) { | |
105 | if ((msg = *dnptrs++) != NULL) { | |
106 | for (cpp = dnptrs; *cpp != NULL; cpp++) | |
107 | ; | |
108 | lpp = cpp; /* end of list to search */ | |
109 | } | |
110 | } else | |
111 | msg = NULL; | |
112 | for (c = *dn++; c != '\0'; ) { | |
113 | /* look to see if we can use pointers */ | |
114 | if (msg != NULL) { | |
115 | if ((l = dn_find(dn-1, msg, dnptrs, lpp)) >= 0) { | |
116 | if (cp+1 >= eob) | |
117 | return (-1); | |
118 | *cp++ = (l >> 8) | INDIR_MASK; | |
119 | *cp++ = l; | |
120 | return (cp - comp_dn); | |
121 | } | |
122 | /* not found, save it */ | |
123 | if (lastdnptr != NULL && cpp < lastdnptr-1) { | |
124 | *cpp++ = cp; | |
125 | *cpp = NULL; | |
126 | } | |
127 | } | |
128 | sp = cp++; /* save ptr to length byte */ | |
129 | do { | |
130 | if (c == '.') { | |
131 | c = *dn++; | |
132 | break; | |
133 | } | |
36534519 RC |
134 | if (c == '\\') { |
135 | if ((c = *dn++) == '\0') | |
136 | break; | |
137 | } | |
fbc82d3e RC |
138 | if (cp >= eob) |
139 | return (-1); | |
140 | *cp++ = c; | |
141 | } while ((c = *dn++) != '\0'); | |
36534519 RC |
142 | /* catch trailing '.'s but not '..' */ |
143 | if ((l = cp - sp - 1) == 0 && c == '\0') { | |
144 | cp--; | |
145 | break; | |
146 | } | |
147 | if (l <= 0 || l > MAXLABEL) | |
fbc82d3e RC |
148 | return (-1); |
149 | *sp = l; | |
150 | } | |
151 | if (cp >= eob) | |
152 | return (-1); | |
153 | *cp++ = '\0'; | |
154 | return (cp - comp_dn); | |
155 | } | |
156 | ||
157 | /* | |
36534519 | 158 | * Skip over a compressed domain name. Return the size or -1. |
fbc82d3e | 159 | */ |
36534519 RC |
160 | dn_skip(comp_dn) |
161 | char *comp_dn; | |
fbc82d3e RC |
162 | { |
163 | register char *cp; | |
164 | register int n; | |
165 | ||
36534519 | 166 | cp = comp_dn; |
fbc82d3e RC |
167 | while (n = *cp++) { |
168 | /* | |
169 | * check for indirection | |
170 | */ | |
171 | switch (n & INDIR_MASK) { | |
172 | case 0: /* normal case, n == len */ | |
173 | cp += n; | |
174 | continue; | |
175 | default: /* illegal type */ | |
176 | return (-1); | |
177 | case INDIR_MASK: /* indirection */ | |
178 | cp++; | |
179 | } | |
180 | break; | |
181 | } | |
36534519 | 182 | return (cp - comp_dn); |
fbc82d3e RC |
183 | } |
184 | ||
185 | /* | |
186 | * Search for expanded name from a list of previously compressed names. | |
187 | * Return the offset from msg if found or -1. | |
188 | */ | |
189 | dn_find(exp_dn, msg, dnptrs, lastdnptr) | |
190 | char *exp_dn, *msg; | |
191 | char **dnptrs, **lastdnptr; | |
192 | { | |
193 | register char *dn, *cp, **cpp; | |
194 | register int n; | |
195 | char *sp; | |
196 | ||
197 | for (cpp = dnptrs; cpp < lastdnptr; cpp++) { | |
198 | dn = exp_dn; | |
199 | sp = cp = *cpp; | |
200 | while (n = *cp++) { | |
201 | /* | |
202 | * check for indirection | |
203 | */ | |
204 | switch (n & INDIR_MASK) { | |
205 | case 0: /* normal case, n == len */ | |
36534519 RC |
206 | while (--n >= 0) { |
207 | if (*dn == '\\') | |
208 | dn++; | |
fbc82d3e RC |
209 | if (*dn++ != *cp++) |
210 | goto next; | |
36534519 | 211 | } |
fbc82d3e RC |
212 | if ((n = *dn++) == '\0' && *cp == '\0') |
213 | return (sp - msg); | |
214 | if (n == '.') | |
215 | continue; | |
216 | goto next; | |
217 | ||
218 | default: /* illegal type */ | |
219 | return (-1); | |
220 | ||
221 | case INDIR_MASK: /* indirection */ | |
222 | cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff)); | |
223 | } | |
224 | } | |
225 | if (*dn == '\0') | |
226 | return (sp - msg); | |
227 | next: ; | |
228 | } | |
229 | return (-1); | |
230 | } | |
11e57e73 RC |
231 | |
232 | /* | |
233 | * Routines to insert/extract short/long's. Must account for byte | |
234 | * order and non-alignment problems. This code at least has the | |
235 | * advantage of being portable. | |
236 | */ | |
237 | ||
238 | u_short | |
239 | getshort(msgp) | |
240 | char *msgp; | |
241 | { | |
242 | register u_char *p = (u_char *) msgp; | |
243 | ||
244 | return ((*p++ << 8) | *p); | |
245 | } | |
246 | ||
247 | u_long | |
248 | getlong(msgp) | |
249 | char *msgp; | |
250 | { | |
251 | register u_char *p = (u_char *) msgp; | |
252 | ||
253 | return ((((((*p++ << 8) | *p++) << 8) | *p++) << 8) | *p); | |
254 | } | |
255 | ||
256 | u_short | |
257 | putshort(s, msgp) | |
258 | register u_short s; | |
259 | register char *msgp; | |
260 | { | |
261 | ||
262 | msgp[1] = s; | |
263 | msgp[0] = s >> 8; | |
264 | } | |
265 | ||
266 | u_long | |
267 | putlong(l, msgp) | |
268 | register u_long l; | |
269 | register char *msgp; | |
270 | { | |
271 | ||
272 | msgp[3] = l; | |
273 | msgp[2] = (l >>= 8); | |
274 | msgp[1] = (l >>= 8); | |
275 | msgp[0] = l >> 8; | |
276 | } |