1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * University Copyright- Copyright (c) 1982, 1986, 1988
32 * The Regents of the University of California
33 * All Rights Reserved
34 *
35 * University Acknowledgment- Portions of this document are derived from
36 * software developed by the University of California, Berkeley, and its
37 * contributors.
38 */
39
40 #pragma ident "%Z%%M% %I% %E% SMI"
41
42 #include <sys/types.h>
43 #include <sys/sockio.h>
44 #include <sys/socket.h>
45 #include <netinet/in.h>
46 #include <stdio.h>
47 #include <arpa/nameser.h>
48 #include <resolv.h>
49
50 #include <netinet/in.h>
51 #include <net/if.h>
52 #include <netinet/if_ether.h>
53 #include <arpa/inet.h>
54
55 #define MAXIFS 256
56
57 /*
58 * Resolver state default settings
59 */
60
61 struct state _res = {
62 RES_TIMEOUT, /* retransmition time interval */
63 4, /* number of times to retransmit */
64 RES_DEFAULT, /* options flags */
65 1, /* number of name servers */
66 };
67
68 /*
69 * Set up default settings. If the configuration file exist, the values
70 * there will have precedence. Otherwise, the server address is set to
71 * INADDR_LOOPBACK and the default domain name comes from the gethostname().
72 * BUT if the NIS/RPC domain name is set, that is used if all else fails.
73 *
74 * The configuration file should only be used if you want to redefine your
75 * domain or run without a server on your machine.
76 *
77 * Note the user can always override then domain name with the environment
78 * variable LOCALDOMAIN which has absolute priority.
79 *
80 *
81 * Return 0 if completes successfully, -1 on error
82 */
83 int
84 res_init(void)
85 {
86 register FILE *fp;
87 register char *cp, **pp;
88 register int n;
89 char buf[BUFSIZ];
90 #ifdef SYSV
91 extern char *strchr();
92 #else
93 extern char *index();
94 #endif
95 extern char *strcpy(), *strncpy();
96 extern char *getenv();
97 int nserv = 0; /* number of nameserver records read from file */
98 int haveenv = 0;
99 int havesearch = 0;
100
101 _res.nsaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); /* INADDR_ANY */
102 _res.nsaddr.sin_family = AF_INET;
103 _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
104 _res.nscount = 1;
105
106 #ifdef SIOCGIFNUM
107 { int numifs, s, n, int_up;
108 struct ifconf ifc;
109 register struct ifreq *ifrp;
110 struct ifreq ifr;
111 unsigned bufsize;
112 unsigned int flags;
113 char *buf;
114 extern void *malloc();
115
116 if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
117 perror("socket");
118 return (-1);
119 }
120 if (ioctl(s, SIOCGIFNUM, (char *)&numifs) < 0) {
121 numifs = MAXIFS;
122 }
123 bufsize = numifs * sizeof (struct ifreq);
124 buf = (char *)malloc(bufsize);
125 if (buf == NULL) {
126 perror("out of memory");
127 close(s);
128 return (-1);
129 }
130 ifc.ifc_len = bufsize;
131 ifc.ifc_buf = buf;
132 if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0) {
133 perror("ifconfig: SIOCGIFCONF");
134 close(s);
135 free(buf);
136 return (-1);
137 }
138
139 int_up = 0;
140 ifrp = ifc.ifc_req;
141 for (n = ifc.ifc_len / sizeof (struct ifreq); n > 0;
142 n--, ifrp++) {
143 memset((void *) &ifr, 0, sizeof (ifr));
144 strncpy(ifr.ifr_name, ifrp->ifr_name,
145 sizeof (ifr.ifr_name));
146 if (ioctl(s, SIOCGIFFLAGS, (char *)&ifr) < 0) {
147 perror("SIOCGIFFLAGS");
148 close(s);
149 free(buf);
150 return (-1);
151 }
152 flags = ifr.ifr_flags;
153 /* we are looking for a non-loopback interface */
154 if ((flags & IFF_UP) && ((flags & IFF_LOOPBACK) == 0))
155 int_up = 1;
156 }
157 close(s);
158 free(buf);
159 if (int_up == 0) /* all the non-LOOPBACK interfaces are DOWN */
160 return (-1);
161 }
162 #endif /* SIOCGIFNUM */
163
164
165 /*
166 * for the benefit of hidden NIS domains, we use the same procedure
167 * as sendmail: convert leading + to dot, then drop to first dot
168 */
169 getdomainname(buf, BUFSIZ);
170 if (buf[0] == '+')
171 buf[0] = '.';
172 #ifdef SYSV
173 cp = strchr(buf, (int)'.');
174 #else
175 cp = index(buf, '.');
176 #endif
177 if (cp == NULL)
178 strcpy(_res.defdname, buf);
179 else
180 strcpy(_res.defdname, cp+1);
181
182 /* Allow user to override the local domain definition */
183 if ((cp = getenv("LOCALDOMAIN")) != NULL) {
184 (void) strncpy(_res.defdname, cp, sizeof (_res.defdname));
185 haveenv++;
186 }
187
188 if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
189 /* read the config file */
190 while (fgets(buf, sizeof (buf), fp) != NULL) {
191 /* read default domain name */
192 if (!strncmp(buf, "domain", sizeof ("domain") - 1)) {
193 if (haveenv) /* skip if have from environ */
194 continue;
195 cp = buf + sizeof ("domain") - 1;
196 while (*cp == ' ' || *cp == '\t')
197 cp++;
198 if ((*cp == '\0') || (*cp == '\n'))
199 continue;
200 (void) strncpy(_res.defdname, cp, sizeof (_res.defdname) - 1);
201 #ifdef SYSV
202 if ((cp = strchr(_res.defdname, (int)'\n')) != NULL)
203 #else
204 if ((cp = index(_res.defdname, '\n')) != NULL)
205 #endif
206 *cp = '\0';
207 havesearch = 0;
208 continue;
209 }
210 /* set search list */
211 if (!strncmp(buf, "search", sizeof ("search") - 1)) {
212 if (haveenv) /* skip if have from environ */
213 continue;
214 cp = buf + sizeof ("search") - 1;
215 while (*cp == ' ' || *cp == '\t')
216 cp++;
217 if ((*cp == '\0') || (*cp == '\n'))
218 continue;
219 (void) strncpy(_res.defdname, cp, sizeof (_res.defdname) - 1);
220 #ifdef SYSV
221 if ((cp = strchr(_res.defdname, (int)'\n')) != NULL)
222 #else
223 if ((cp = index(_res.defdname, '\n')) != NULL)
224 #endif
225 *cp = '\0';
226 /*
227 * Set search list to be blank-separated strings
228 * on rest of line.
229 */
230 cp = _res.defdname;
231 pp = _res.dnsrch;
232 *pp++ = cp;
233 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
234 if (*cp == ' ' || *cp == '\t') {
235 *cp = 0;
236 n = 1;
237 } else if (n) {
238 *pp++ = cp;
239 n = 0;
240 }
241 }
242 /* null terminate last domain if there are excess */
243 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
244 cp++;
245 *cp = '\0';
246 *pp++ = 0;
247 havesearch = 1;
248 continue;
249 }
250 /* read nameservers to query */
251 if (!strncmp(buf, "nameserver", sizeof ("nameserver") - 1) &&
252 (nserv < MAXNS)) {
253 cp = buf + sizeof ("nameserver") - 1;
254 while (*cp == ' ' || *cp == '\t')
255 cp++;
256 if ((*cp == '\0') || (*cp == '\n'))
257 continue;
258 if ((_res.nsaddr_list[nserv].sin_addr.s_addr =
259 inet_addr(cp)) == (unsigned) -1) {
260 _res.nsaddr_list[n].sin_addr.s_addr = INADDR_ANY;
261 continue;
262 }
263 _res.nsaddr_list[nserv].sin_family = AF_INET;
264 _res.nsaddr_list[nserv].sin_port = htons(NAMESERVER_PORT);
265 nserv++;
266 continue;
267 }
268 }
269 if (nserv > 1)
270 _res.nscount = nserv;
271 (void) fclose(fp);
272 }
273 if (_res.defdname[0] == 0) {
274 if (gethostname(buf, sizeof (_res.defdname)) == 0 &&
275 #ifdef SYSV
276 (cp = strchr(buf, (int)'.')))
277 #else
278 (cp = index(buf, '.')))
279 #endif
280 (void) strcpy(_res.defdname, cp + 1);
281 }
282
283 /* find components of local domain that might be searched */
284 if (havesearch == 0) {
285 pp = _res.dnsrch;
286 *pp++ = _res.defdname;
287 for (cp = _res.defdname, n = 0; *cp; cp++)
288 if (*cp == '.')
289 n++;
290 cp = _res.defdname;
291 for (; n >= LOCALDOMAINPARTS && pp < _res.dnsrch + MAXDFLSRCH; n--) {
292 #ifdef SYSV
293 cp = strchr(cp, (int)'.');
294 #else
295 cp = index(cp, '.');
296 #endif
297 *pp++ = ++cp;
298 }
299 *pp++ = 0;
300 }
301 _res.options |= RES_INIT;
302 return (0);
303 }