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 */
61extern int
62getdomainname(char *, int);
63
64#define	MAXIFS	256
65
66/*
67 * Resolver state default settings
68 */
69
70struct 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 */
92int
93res_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}
305