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 2015 Gary Mills
24 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
25 * Use is subject to license terms.
26 */
27
28 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
29 /* All Rights Reserved */
30
31 /*
32 * University Copyright- Copyright (c) 1982, 1986, 1988
33 * The Regents of the University of California
34 * All Rights Reserved
35 *
36 * University Acknowledgment- Portions of this document are derived from
37 * software developed by the University of California, Berkeley, and its
38 * contributors.
39 */
40
41 #include <sys/types.h>
42 #include <sys/sockio.h>
43 #include <sys/socket.h>
44 #include <netinet/in.h>
45 #include <stdio.h>
46 #include <string.h>
47 #include <stdlib.h>
48 #include <unistd.h>
49 #include <stropts.h>
50 #include <arpa/nameser.h>
51 #include <resolv.h>
52
53 #include <netinet/in.h>
54 #include <net/if.h>
55 #include <netinet/if_ether.h>
56 #include <arpa/inet.h>
57
58 /*
59 * Undocumented external function in libnsl
60 */
61 extern int
62 getdomainname(char *, int);
63
64 #define MAXIFS 256
65
66 /*
67 * Resolver state default settings
68 */
69
70 struct state _res = {
71 RES_TIMEOUT, /* retransmition time interval */
72 4, /* number of times to retransmit */
73 RES_DEFAULT, /* options flags */
74 1, /* number of name servers */
75 };
76
77 /*
78 * Set up default settings. If the configuration file exist, the values
79 * there will have precedence. Otherwise, the server address is set to
80 * INADDR_LOOPBACK and the default domain name comes from the gethostname().
81 * BUT if the NIS/RPC domain name is set, that is used if all else fails.
82 *
83 * The configuration file should only be used if you want to redefine your
84 * domain or run without a server on your machine.
85 *
86 * Note the user can always override then domain name with the environment
87 * variable LOCALDOMAIN which has absolute priority.
88 *
89 *
90 * Return 0 if completes successfully, -1 on error
91 */
92 int
93 res_init(void)
94 {
95 register FILE *fp;
96 register char *cp, **pp;
97 register int n;
98 char buf[BUFSIZ];
99 int nserv = 0; /* number of nameserver records read from file */
100 int haveenv = 0;
101 int havesearch = 0;
102
103 _res.nsaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); /* INADDR_ANY */
104 _res.nsaddr.sin_family = AF_INET;
105 _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
106 _res.nscount = 1;
107
108 #ifdef SIOCGIFNUM
109 { int numifs, s, n, int_up;
110 struct ifconf ifc;
111 register struct ifreq *ifrp;
112 struct ifreq ifr;
113 unsigned bufsize;
114 unsigned int flags;
115 char *buf;
116
117 if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
118 perror("socket");
119 return (-1);
120 }
121 if (ioctl(s, SIOCGIFNUM, (char *)&numifs) < 0) {
122 numifs = MAXIFS;
123 }
124 bufsize = numifs * sizeof (struct ifreq);
125 buf = (char *)malloc(bufsize);
126 if (buf == NULL) {
127 perror("out of memory");
128 (void) close(s);
129 return (-1);
130 }
131 ifc.ifc_len = bufsize;
132 ifc.ifc_buf = buf;
133 if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0) {
134 perror("ifconfig: SIOCGIFCONF");
135 (void) close(s);
136 free(buf);
137 return (-1);
138 }
139
140 int_up = 0;
141 ifrp = ifc.ifc_req;
142 for (n = ifc.ifc_len / sizeof (struct ifreq); n > 0;
143 n--, ifrp++) {
144 (void) memset((void *) &ifr, 0, sizeof (ifr));
145 strncpy(ifr.ifr_name, ifrp->ifr_name,
146 sizeof (ifr.ifr_name));
147 if (ioctl(s, SIOCGIFFLAGS, (char *)&ifr) < 0) {
148 perror("SIOCGIFFLAGS");
149 (void) close(s);
150 free(buf);
151 return (-1);
152 }
153 flags = ifr.ifr_flags;
154 /* we are looking for a non-loopback interface */
155 if ((flags & IFF_UP) && ((flags & IFF_LOOPBACK) == 0))
156 int_up = 1;
157 }
158 (void) close(s);
159 free(buf);
160 if (int_up == 0) /* all the non-LOOPBACK interfaces are DOWN */
161 return (-1);
162 }
163 #endif /* SIOCGIFNUM */
164
165
166 /*
167 * for the benefit of hidden NIS domains, we use the same procedure
168 * as sendmail: convert leading + to dot, then drop to first dot
169 */
170 (void) getdomainname(buf, BUFSIZ);
171 if (buf[0] == '+')
172 buf[0] = '.';
173 #ifdef SYSV
174 cp = strchr(buf, (int)'.');
175 #else
176 cp = index(buf, '.');
177 #endif
178 if (cp == NULL)
179 strcpy(_res.defdname, buf);
180 else
181 strcpy(_res.defdname, cp+1);
182
183 /* Allow user to override the local domain definition */
184 if ((cp = getenv("LOCALDOMAIN")) != NULL) {
185 (void) strncpy(_res.defdname, cp, sizeof (_res.defdname));
186 haveenv++;
187 }
188
189 if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
190 /* read the config file */
191 while (fgets(buf, sizeof (buf), fp) != NULL) {
192 /* read default domain name */
193 if (!strncmp(buf, "domain", sizeof ("domain") - 1)) {
194 if (haveenv) /* skip if have from environ */
195 continue;
196 cp = buf + sizeof ("domain") - 1;
197 while (*cp == ' ' || *cp == '\t')
198 cp++;
199 if ((*cp == '\0') || (*cp == '\n'))
200 continue;
201 (void) strncpy(_res.defdname, cp, sizeof (_res.defdname) - 1);
202 #ifdef SYSV
203 if ((cp = strchr(_res.defdname, (int)'\n')) != NULL)
204 #else
205 if ((cp = index(_res.defdname, '\n')) != NULL)
206 #endif
207 *cp = '\0';
208 havesearch = 0;
209 continue;
210 }
211 /* set search list */
212 if (!strncmp(buf, "search", sizeof ("search") - 1)) {
213 if (haveenv) /* skip if have from environ */
214 continue;
215 cp = buf + sizeof ("search") - 1;
216 while (*cp == ' ' || *cp == '\t')
217 cp++;
218 if ((*cp == '\0') || (*cp == '\n'))
219 continue;
220 (void) strncpy(_res.defdname, cp, sizeof (_res.defdname) - 1);
221 #ifdef SYSV
222 if ((cp = strchr(_res.defdname, (int)'\n')) != NULL)
223 #else
224 if ((cp = index(_res.defdname, '\n')) != NULL)
225 #endif
226 *cp = '\0';
227 /*
228 * Set search list to be blank-separated strings
229 * on rest of line.
230 */
231 cp = _res.defdname;
232 pp = _res.dnsrch;
233 *pp++ = cp;
234 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
235 if (*cp == ' ' || *cp == '\t') {
236 *cp = 0;
237 n = 1;
238 } else if (n) {
239 *pp++ = cp;
240 n = 0;
241 }
242 }
243 /* null terminate last domain if there are excess */
244 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
245 cp++;
246 *cp = '\0';
247 *pp++ = 0;
248 havesearch = 1;
249 continue;
250 }
251 /* read nameservers to query */
252 if (!strncmp(buf, "nameserver", sizeof ("nameserver") - 1) &&
253 (nserv < MAXNS)) {
254 cp = buf + sizeof ("nameserver") - 1;
255 while (*cp == ' ' || *cp == '\t')
256 cp++;
257 if ((*cp == '\0') || (*cp == '\n'))
258 continue;
259 if ((_res.nsaddr_list[nserv].sin_addr.s_addr =
260 inet_addr(cp)) == (unsigned) -1) {
261 _res.nsaddr_list[n].sin_addr.s_addr = INADDR_ANY;
262 continue;
263 }
264 _res.nsaddr_list[nserv].sin_family = AF_INET;
265 _res.nsaddr_list[nserv].sin_port = htons(NAMESERVER_PORT);
266 nserv++;
267 continue;
268 }
269 }
270 if (nserv > 1)
271 _res.nscount = nserv;
272 (void) fclose(fp);
273 }
274 if (_res.defdname[0] == 0) {
275 if (gethostname(buf, sizeof (_res.defdname)) == 0 &&
276 #ifdef SYSV
277 (cp = strchr(buf, (int)'.')))
278 #else
279 (cp = index(buf, '.')))
280 #endif
281 (void) strcpy(_res.defdname, cp + 1);
282 }
283
284 /* find components of local domain that might be searched */
285 if (havesearch == 0) {
286 pp = _res.dnsrch;
287 *pp++ = _res.defdname;
288 for (cp = _res.defdname, n = 0; *cp; cp++)
289 if (*cp == '.')
290 n++;
291 cp = _res.defdname;
292 for (; n >= LOCALDOMAINPARTS && pp < _res.dnsrch + MAXDFLSRCH; n--) {
293 #ifdef SYSV
294 cp = strchr(cp, (int)'.');
295 #else
296 cp = index(cp, '.');
297 #endif
298 *pp++ = ++cp;
299 }
300 *pp++ = 0;
301 }
302 _res.options |= RES_INIT;
303 return (0);
304 }