xref: /freebsd/contrib/sendmail/src/domain.c (revision 602a2b1b1d5877cb573baf0407540810a490b0cf)
1c2aa98e2SPeter Wemm /*
2602a2b1bSGregory Neil Shapiro  * Copyright (c) 1998-2001 Sendmail, Inc. and its suppliers.
306f25ae9SGregory Neil Shapiro  *	All rights reserved.
4c2aa98e2SPeter Wemm  * Copyright (c) 1986, 1995-1997 Eric P. Allman.  All rights reserved.
5c2aa98e2SPeter Wemm  * Copyright (c) 1988, 1993
6c2aa98e2SPeter Wemm  *	The Regents of the University of California.  All rights reserved.
7c2aa98e2SPeter Wemm  *
8c2aa98e2SPeter Wemm  * By using this file, you agree to the terms and conditions set
9c2aa98e2SPeter Wemm  * forth in the LICENSE file which can be found at the top level of
10c2aa98e2SPeter Wemm  * the sendmail distribution.
11c2aa98e2SPeter Wemm  *
12c2aa98e2SPeter Wemm  */
13c2aa98e2SPeter Wemm 
1406f25ae9SGregory Neil Shapiro #include <sendmail.h>
15c2aa98e2SPeter Wemm 
16c2aa98e2SPeter Wemm #ifndef lint
17c2aa98e2SPeter Wemm # if NAMED_BIND
18602a2b1bSGregory Neil Shapiro static char id[] = "@(#)$Id: domain.c,v 8.114.6.1.2.8 2001/02/12 21:40:19 gshapiro Exp $ (with name server)";
1906f25ae9SGregory Neil Shapiro # else /* NAMED_BIND */
20602a2b1bSGregory Neil Shapiro static char id[] = "@(#)$Id: domain.c,v 8.114.6.1.2.8 2001/02/12 21:40:19 gshapiro Exp $ (without name server)";
2106f25ae9SGregory Neil Shapiro # endif /* NAMED_BIND */
2206f25ae9SGregory Neil Shapiro #endif /* ! lint */
2306f25ae9SGregory Neil Shapiro 
24c2aa98e2SPeter Wemm 
25c2aa98e2SPeter Wemm #if NAMED_BIND
26c2aa98e2SPeter Wemm 
27c2aa98e2SPeter Wemm # include <arpa/inet.h>
28c2aa98e2SPeter Wemm 
29c2aa98e2SPeter Wemm /*
30c2aa98e2SPeter Wemm **  The standard udp packet size PACKETSZ (512) is not sufficient for some
31c2aa98e2SPeter Wemm **  nameserver answers containing very many resource records. The resolver
32c2aa98e2SPeter Wemm **  may switch to tcp and retry if it detects udp packet overflow.
33c2aa98e2SPeter Wemm **  Also note that the resolver routines res_query and res_search return
34c2aa98e2SPeter Wemm **  the size of the *un*truncated answer in case the supplied answer buffer
35c2aa98e2SPeter Wemm **  it not big enough to accommodate the entire answer.
36c2aa98e2SPeter Wemm */
37c2aa98e2SPeter Wemm 
38c2aa98e2SPeter Wemm # ifndef MAXPACKET
39c2aa98e2SPeter Wemm #  define MAXPACKET 8192	/* max packet size used internally by BIND */
4006f25ae9SGregory Neil Shapiro # endif /* ! MAXPACKET */
41c2aa98e2SPeter Wemm 
42c2aa98e2SPeter Wemm typedef union
43c2aa98e2SPeter Wemm {
44c2aa98e2SPeter Wemm 	HEADER	qb1;
45c2aa98e2SPeter Wemm 	u_char	qb2[MAXPACKET];
46c2aa98e2SPeter Wemm } querybuf;
47c2aa98e2SPeter Wemm 
48c2aa98e2SPeter Wemm # ifndef MXHOSTBUFSIZE
49c2aa98e2SPeter Wemm #  define MXHOSTBUFSIZE	(128 * MAXMXHOSTS)
5006f25ae9SGregory Neil Shapiro # endif /* ! MXHOSTBUFSIZE */
51c2aa98e2SPeter Wemm 
52c2aa98e2SPeter Wemm static char	MXHostBuf[MXHOSTBUFSIZE];
53c2aa98e2SPeter Wemm 
54c2aa98e2SPeter Wemm # ifndef MAXDNSRCH
55c2aa98e2SPeter Wemm #  define MAXDNSRCH	6	/* number of possible domains to search */
5606f25ae9SGregory Neil Shapiro # endif /* ! MAXDNSRCH */
5706f25ae9SGregory Neil Shapiro 
5806f25ae9SGregory Neil Shapiro # ifndef RES_DNSRCH_VARIABLE
5906f25ae9SGregory Neil Shapiro #  define RES_DNSRCH_VARIABLE	_res.dnsrch
6006f25ae9SGregory Neil Shapiro # endif /* ! RES_DNSRCH_VARIABLE */
61c2aa98e2SPeter Wemm 
62c2aa98e2SPeter Wemm # ifndef MAX
63c2aa98e2SPeter Wemm #  define MAX(a, b)	((a) > (b) ? (a) : (b))
6406f25ae9SGregory Neil Shapiro # endif /* ! MAX */
65c2aa98e2SPeter Wemm 
66c2aa98e2SPeter Wemm # ifndef NO_DATA
67c2aa98e2SPeter Wemm #  define NO_DATA	NO_ADDRESS
6806f25ae9SGregory Neil Shapiro # endif /* ! NO_DATA */
69c2aa98e2SPeter Wemm 
70c2aa98e2SPeter Wemm # ifndef HFIXEDSZ
71c2aa98e2SPeter Wemm #  define HFIXEDSZ	12	/* sizeof(HEADER) */
7206f25ae9SGregory Neil Shapiro # endif /* ! HFIXEDSZ */
73c2aa98e2SPeter Wemm 
74c2aa98e2SPeter Wemm # define MAXCNAMEDEPTH	10	/* maximum depth of CNAME recursion */
75c2aa98e2SPeter Wemm 
76c2aa98e2SPeter Wemm # if defined(__RES) && (__RES >= 19940415)
77c2aa98e2SPeter Wemm #  define RES_UNC_T	char *
7806f25ae9SGregory Neil Shapiro # else /* defined(__RES) && (__RES >= 19940415) */
79c2aa98e2SPeter Wemm #  define RES_UNC_T	u_char *
8006f25ae9SGregory Neil Shapiro # endif /* defined(__RES) && (__RES >= 19940415) */
8106f25ae9SGregory Neil Shapiro 
8206f25ae9SGregory Neil Shapiro static char	*gethostalias __P((char *));
8306f25ae9SGregory Neil Shapiro static int	mxrand __P((char *));
8406f25ae9SGregory Neil Shapiro 
85c2aa98e2SPeter Wemm /*
86c2aa98e2SPeter Wemm **  GETMXRR -- get MX resource records for a domain
87c2aa98e2SPeter Wemm **
88c2aa98e2SPeter Wemm **	Parameters:
89c2aa98e2SPeter Wemm **		host -- the name of the host to MX.
90c2aa98e2SPeter Wemm **		mxhosts -- a pointer to a return buffer of MX records.
9106f25ae9SGregory Neil Shapiro **		mxprefs -- a pointer to a return buffer of MX preferences.
9206f25ae9SGregory Neil Shapiro **			If NULL, don't try to populate.
93c2aa98e2SPeter Wemm **		droplocalhost -- If TRUE, all MX records less preferred
94c2aa98e2SPeter Wemm **			than the local host (as determined by $=w) will
95c2aa98e2SPeter Wemm **			be discarded.
96c2aa98e2SPeter Wemm **		rcode -- a pointer to an EX_ status code.
97c2aa98e2SPeter Wemm **
98c2aa98e2SPeter Wemm **	Returns:
99c2aa98e2SPeter Wemm **		The number of MX records found.
100c2aa98e2SPeter Wemm **		-1 if there is an internal failure.
101c2aa98e2SPeter Wemm **		If no MX records are found, mxhosts[0] is set to host
102c2aa98e2SPeter Wemm **			and 1 is returned.
103c2aa98e2SPeter Wemm */
104c2aa98e2SPeter Wemm 
105c2aa98e2SPeter Wemm int
10606f25ae9SGregory Neil Shapiro getmxrr(host, mxhosts, mxprefs, droplocalhost, rcode)
107c2aa98e2SPeter Wemm 	char *host;
108c2aa98e2SPeter Wemm 	char **mxhosts;
10906f25ae9SGregory Neil Shapiro 	u_short *mxprefs;
110c2aa98e2SPeter Wemm 	bool droplocalhost;
111c2aa98e2SPeter Wemm 	int *rcode;
112c2aa98e2SPeter Wemm {
113c2aa98e2SPeter Wemm 	register u_char *eom, *cp;
114c2aa98e2SPeter Wemm 	register int i, j, n;
115c2aa98e2SPeter Wemm 	int nmx = 0;
116c2aa98e2SPeter Wemm 	register char *bp;
117c2aa98e2SPeter Wemm 	HEADER *hp;
118c2aa98e2SPeter Wemm 	querybuf answer;
119c2aa98e2SPeter Wemm 	int ancount, qdcount, buflen;
120c2aa98e2SPeter Wemm 	bool seenlocal = FALSE;
121c2aa98e2SPeter Wemm 	u_short pref, type;
122c2aa98e2SPeter Wemm 	u_short localpref = 256;
123c2aa98e2SPeter Wemm 	char *fallbackMX = FallBackMX;
124c2aa98e2SPeter Wemm 	bool trycanon = FALSE;
12506f25ae9SGregory Neil Shapiro 	u_short *prefs;
126c2aa98e2SPeter Wemm 	int (*resfunc)();
127c2aa98e2SPeter Wemm 	u_short prefer[MAXMXHOSTS];
128c2aa98e2SPeter Wemm 	int weight[MAXMXHOSTS];
12906f25ae9SGregory Neil Shapiro 	extern int res_query(), res_search();
130c2aa98e2SPeter Wemm 
131c2aa98e2SPeter Wemm 	if (tTd(8, 2))
13206f25ae9SGregory Neil Shapiro 		dprintf("getmxrr(%s, droplocalhost=%d)\n",
13306f25ae9SGregory Neil Shapiro 			host, droplocalhost);
134c2aa98e2SPeter Wemm 
135c2aa98e2SPeter Wemm 	if (fallbackMX != NULL && droplocalhost &&
136c2aa98e2SPeter Wemm 	    wordinclass(fallbackMX, 'w'))
137c2aa98e2SPeter Wemm 	{
138c2aa98e2SPeter Wemm 		/* don't use fallback for this pass */
139c2aa98e2SPeter Wemm 		fallbackMX = NULL;
140c2aa98e2SPeter Wemm 	}
141c2aa98e2SPeter Wemm 
142c2aa98e2SPeter Wemm 	*rcode = EX_OK;
143c2aa98e2SPeter Wemm 
14406f25ae9SGregory Neil Shapiro 	if (mxprefs != NULL)
14506f25ae9SGregory Neil Shapiro 		prefs = mxprefs;
14606f25ae9SGregory Neil Shapiro 	else
14706f25ae9SGregory Neil Shapiro 		prefs = prefer;
14806f25ae9SGregory Neil Shapiro 
14906f25ae9SGregory Neil Shapiro 
150c2aa98e2SPeter Wemm 	/* efficiency hack -- numeric or non-MX lookups */
151c2aa98e2SPeter Wemm 	if (host[0] == '[')
152c2aa98e2SPeter Wemm 		goto punt;
153c2aa98e2SPeter Wemm 
154c2aa98e2SPeter Wemm 	/*
155c2aa98e2SPeter Wemm 	**  If we don't have MX records in our host switch, don't
156c2aa98e2SPeter Wemm 	**  try for MX records.  Note that this really isn't "right",
157c2aa98e2SPeter Wemm 	**  since we might be set up to try NIS first and then DNS;
158c2aa98e2SPeter Wemm 	**  if the host is found in NIS we really shouldn't be doing
159c2aa98e2SPeter Wemm 	**  MX lookups.  However, that should be a degenerate case.
160c2aa98e2SPeter Wemm 	*/
161c2aa98e2SPeter Wemm 
162c2aa98e2SPeter Wemm 	if (!UseNameServer)
163c2aa98e2SPeter Wemm 		goto punt;
164c2aa98e2SPeter Wemm 	if (HasWildcardMX && ConfigLevel >= 6)
165c2aa98e2SPeter Wemm 		resfunc = res_query;
166c2aa98e2SPeter Wemm 	else
167c2aa98e2SPeter Wemm 		resfunc = res_search;
168c2aa98e2SPeter Wemm 
169c2aa98e2SPeter Wemm 	errno = 0;
170c2aa98e2SPeter Wemm 	n = (*resfunc)(host, C_IN, T_MX, (u_char *) &answer, sizeof(answer));
171c2aa98e2SPeter Wemm 	if (n < 0)
172c2aa98e2SPeter Wemm 	{
173c2aa98e2SPeter Wemm 		if (tTd(8, 1))
17406f25ae9SGregory Neil Shapiro 			dprintf("getmxrr: res_search(%s) failed (errno=%d, h_errno=%d)\n",
175c2aa98e2SPeter Wemm 			    (host == NULL) ? "<NULL>" : host, errno, h_errno);
176c2aa98e2SPeter Wemm 		switch (h_errno)
177c2aa98e2SPeter Wemm 		{
178c2aa98e2SPeter Wemm 		  case NO_DATA:
179c2aa98e2SPeter Wemm 			trycanon = TRUE;
18006f25ae9SGregory Neil Shapiro 			/* FALLTHROUGH */
181c2aa98e2SPeter Wemm 
182c2aa98e2SPeter Wemm 		  case NO_RECOVERY:
183c2aa98e2SPeter Wemm 			/* no MX data on this host */
184c2aa98e2SPeter Wemm 			goto punt;
185c2aa98e2SPeter Wemm 
186c2aa98e2SPeter Wemm 		  case HOST_NOT_FOUND:
187c2aa98e2SPeter Wemm # if BROKEN_RES_SEARCH
188c2aa98e2SPeter Wemm 		  case 0:	/* Ultrix resolver retns failure w/ h_errno=0 */
18906f25ae9SGregory Neil Shapiro # endif /* BROKEN_RES_SEARCH */
190c2aa98e2SPeter Wemm 			/* host doesn't exist in DNS; might be in /etc/hosts */
191c2aa98e2SPeter Wemm 			trycanon = TRUE;
192c2aa98e2SPeter Wemm 			*rcode = EX_NOHOST;
193c2aa98e2SPeter Wemm 			goto punt;
194c2aa98e2SPeter Wemm 
195c2aa98e2SPeter Wemm 		  case TRY_AGAIN:
196c2aa98e2SPeter Wemm 		  case -1:
197c2aa98e2SPeter Wemm 			/* couldn't connect to the name server */
198c2aa98e2SPeter Wemm 			if (fallbackMX != NULL)
199c2aa98e2SPeter Wemm 			{
200c2aa98e2SPeter Wemm 				/* name server is hosed -- push to fallback */
20106f25ae9SGregory Neil Shapiro 				if (nmx > 0)
20206f25ae9SGregory Neil Shapiro 					prefs[nmx] = prefs[nmx - 1] + 1;
20306f25ae9SGregory Neil Shapiro 				else
20406f25ae9SGregory Neil Shapiro 					prefs[nmx] = 0;
205c2aa98e2SPeter Wemm 				mxhosts[nmx++] = fallbackMX;
206c2aa98e2SPeter Wemm 				return nmx;
207c2aa98e2SPeter Wemm 			}
208c2aa98e2SPeter Wemm 			/* it might come up later; better queue it up */
209c2aa98e2SPeter Wemm 			*rcode = EX_TEMPFAIL;
210c2aa98e2SPeter Wemm 			break;
211c2aa98e2SPeter Wemm 
212c2aa98e2SPeter Wemm 		  default:
213c2aa98e2SPeter Wemm 			syserr("getmxrr: res_search (%s) failed with impossible h_errno (%d)\n",
214c2aa98e2SPeter Wemm 				host, h_errno);
215c2aa98e2SPeter Wemm 			*rcode = EX_OSERR;
216c2aa98e2SPeter Wemm 			break;
217c2aa98e2SPeter Wemm 		}
218c2aa98e2SPeter Wemm 
219c2aa98e2SPeter Wemm 		/* irreconcilable differences */
22006f25ae9SGregory Neil Shapiro 		return -1;
221c2aa98e2SPeter Wemm 	}
222c2aa98e2SPeter Wemm 
223c2aa98e2SPeter Wemm 	/* avoid problems after truncation in tcp packets */
224c2aa98e2SPeter Wemm 	if (n > sizeof(answer))
225c2aa98e2SPeter Wemm 		n = sizeof(answer);
226c2aa98e2SPeter Wemm 
227c2aa98e2SPeter Wemm 	/* find first satisfactory answer */
228c2aa98e2SPeter Wemm 	hp = (HEADER *)&answer;
229c2aa98e2SPeter Wemm 	cp = (u_char *)&answer + HFIXEDSZ;
230c2aa98e2SPeter Wemm 	eom = (u_char *)&answer + n;
23106f25ae9SGregory Neil Shapiro 	for (qdcount = ntohs((u_short)hp->qdcount);
23206f25ae9SGregory Neil Shapiro 	     qdcount--;
23306f25ae9SGregory Neil Shapiro 	     cp += n + QFIXEDSZ)
23406f25ae9SGregory Neil Shapiro 	{
235c2aa98e2SPeter Wemm 		if ((n = dn_skipname(cp, eom)) < 0)
236c2aa98e2SPeter Wemm 			goto punt;
23706f25ae9SGregory Neil Shapiro 	}
238c2aa98e2SPeter Wemm 	buflen = sizeof(MXHostBuf) - 1;
239c2aa98e2SPeter Wemm 	bp = MXHostBuf;
24006f25ae9SGregory Neil Shapiro 	ancount = ntohs((u_short)hp->ancount);
241c2aa98e2SPeter Wemm 	while (--ancount >= 0 && cp < eom && nmx < MAXMXHOSTS - 1)
242c2aa98e2SPeter Wemm 	{
243c2aa98e2SPeter Wemm 		if ((n = dn_expand((u_char *)&answer,
244c2aa98e2SPeter Wemm 		    eom, cp, (RES_UNC_T) bp, buflen)) < 0)
245c2aa98e2SPeter Wemm 			break;
246c2aa98e2SPeter Wemm 		cp += n;
247c2aa98e2SPeter Wemm 		GETSHORT(type, cp);
248c2aa98e2SPeter Wemm 		cp += INT16SZ + INT32SZ;
249c2aa98e2SPeter Wemm 		GETSHORT(n, cp);
250c2aa98e2SPeter Wemm 		if (type != T_MX)
251c2aa98e2SPeter Wemm 		{
252c2aa98e2SPeter Wemm 			if (tTd(8, 8) || _res.options & RES_DEBUG)
25306f25ae9SGregory Neil Shapiro 				dprintf("unexpected answer type %d, size %d\n",
254c2aa98e2SPeter Wemm 					type, n);
255c2aa98e2SPeter Wemm 			cp += n;
256c2aa98e2SPeter Wemm 			continue;
257c2aa98e2SPeter Wemm 		}
258c2aa98e2SPeter Wemm 		GETSHORT(pref, cp);
259c2aa98e2SPeter Wemm 		if ((n = dn_expand((u_char *)&answer, eom, cp,
260c2aa98e2SPeter Wemm 				   (RES_UNC_T) bp, buflen)) < 0)
261c2aa98e2SPeter Wemm 			break;
262c2aa98e2SPeter Wemm 		cp += n;
263c2aa98e2SPeter Wemm 		if (wordinclass(bp, 'w'))
264c2aa98e2SPeter Wemm 		{
265c2aa98e2SPeter Wemm 			if (tTd(8, 3))
26606f25ae9SGregory Neil Shapiro 				dprintf("found localhost (%s) in MX list, pref=%d\n",
267c2aa98e2SPeter Wemm 					bp, pref);
268c2aa98e2SPeter Wemm 			if (droplocalhost)
269c2aa98e2SPeter Wemm 			{
270c2aa98e2SPeter Wemm 				if (!seenlocal || pref < localpref)
271c2aa98e2SPeter Wemm 					localpref = pref;
272c2aa98e2SPeter Wemm 				seenlocal = TRUE;
273c2aa98e2SPeter Wemm 				continue;
274c2aa98e2SPeter Wemm 			}
275c2aa98e2SPeter Wemm 			weight[nmx] = 0;
276c2aa98e2SPeter Wemm 		}
277c2aa98e2SPeter Wemm 		else
278c2aa98e2SPeter Wemm 			weight[nmx] = mxrand(bp);
27906f25ae9SGregory Neil Shapiro 		prefs[nmx] = pref;
280c2aa98e2SPeter Wemm 		mxhosts[nmx++] = bp;
281c2aa98e2SPeter Wemm 		n = strlen(bp);
282c2aa98e2SPeter Wemm 		bp += n;
283c2aa98e2SPeter Wemm 		if (bp[-1] != '.')
284c2aa98e2SPeter Wemm 		{
285c2aa98e2SPeter Wemm 			*bp++ = '.';
286c2aa98e2SPeter Wemm 			n++;
287c2aa98e2SPeter Wemm 		}
288c2aa98e2SPeter Wemm 		*bp++ = '\0';
289c2aa98e2SPeter Wemm 		buflen -= n + 1;
290c2aa98e2SPeter Wemm 	}
291c2aa98e2SPeter Wemm 
292c2aa98e2SPeter Wemm 	/* sort the records */
293c2aa98e2SPeter Wemm 	for (i = 0; i < nmx; i++)
294c2aa98e2SPeter Wemm 	{
295c2aa98e2SPeter Wemm 		for (j = i + 1; j < nmx; j++)
296c2aa98e2SPeter Wemm 		{
29706f25ae9SGregory Neil Shapiro 			if (prefs[i] > prefs[j] ||
29806f25ae9SGregory Neil Shapiro 			    (prefs[i] == prefs[j] && weight[i] > weight[j]))
299c2aa98e2SPeter Wemm 			{
300c2aa98e2SPeter Wemm 				register int temp;
301c2aa98e2SPeter Wemm 				register char *temp1;
302c2aa98e2SPeter Wemm 
30306f25ae9SGregory Neil Shapiro 				temp = prefs[i];
30406f25ae9SGregory Neil Shapiro 				prefs[i] = prefs[j];
30506f25ae9SGregory Neil Shapiro 				prefs[j] = temp;
306c2aa98e2SPeter Wemm 				temp1 = mxhosts[i];
307c2aa98e2SPeter Wemm 				mxhosts[i] = mxhosts[j];
308c2aa98e2SPeter Wemm 				mxhosts[j] = temp1;
309c2aa98e2SPeter Wemm 				temp = weight[i];
310c2aa98e2SPeter Wemm 				weight[i] = weight[j];
311c2aa98e2SPeter Wemm 				weight[j] = temp;
312c2aa98e2SPeter Wemm 			}
313c2aa98e2SPeter Wemm 		}
31406f25ae9SGregory Neil Shapiro 		if (seenlocal && prefs[i] >= localpref)
315c2aa98e2SPeter Wemm 		{
316c2aa98e2SPeter Wemm 			/* truncate higher preference part of list */
317c2aa98e2SPeter Wemm 			nmx = i;
318c2aa98e2SPeter Wemm 		}
319c2aa98e2SPeter Wemm 	}
320c2aa98e2SPeter Wemm 
321c2aa98e2SPeter Wemm 	/* delete duplicates from list (yes, some bozos have duplicates) */
322c2aa98e2SPeter Wemm 	for (i = 0; i < nmx - 1; )
323c2aa98e2SPeter Wemm 	{
324c2aa98e2SPeter Wemm 		if (strcasecmp(mxhosts[i], mxhosts[i + 1]) != 0)
325c2aa98e2SPeter Wemm 			i++;
326c2aa98e2SPeter Wemm 		else
327c2aa98e2SPeter Wemm 		{
328c2aa98e2SPeter Wemm 			/* compress out duplicate */
329c2aa98e2SPeter Wemm 			for (j = i + 1; j < nmx; j++)
33006f25ae9SGregory Neil Shapiro 			{
331c2aa98e2SPeter Wemm 				mxhosts[j] = mxhosts[j + 1];
33206f25ae9SGregory Neil Shapiro 				prefs[j] = prefs[j + 1];
33306f25ae9SGregory Neil Shapiro 			}
334c2aa98e2SPeter Wemm 			nmx--;
335c2aa98e2SPeter Wemm 		}
336c2aa98e2SPeter Wemm 	}
337c2aa98e2SPeter Wemm 
338c2aa98e2SPeter Wemm 	if (nmx == 0)
339c2aa98e2SPeter Wemm 	{
340c2aa98e2SPeter Wemm punt:
34106f25ae9SGregory Neil Shapiro 		if (seenlocal)
342c2aa98e2SPeter Wemm 		{
34306f25ae9SGregory Neil Shapiro 			struct hostent *h = NULL;
34406f25ae9SGregory Neil Shapiro 
345c2aa98e2SPeter Wemm 			/*
346c2aa98e2SPeter Wemm 			**  If we have deleted all MX entries, this is
347c2aa98e2SPeter Wemm 			**  an error -- we should NEVER send to a host that
348c2aa98e2SPeter Wemm 			**  has an MX, and this should have been caught
349c2aa98e2SPeter Wemm 			**  earlier in the config file.
350c2aa98e2SPeter Wemm 			**
351c2aa98e2SPeter Wemm 			**  Some sites prefer to go ahead and try the
352c2aa98e2SPeter Wemm 			**  A record anyway; that case is handled by
353c2aa98e2SPeter Wemm 			**  setting TryNullMXList.  I believe this is a
354c2aa98e2SPeter Wemm 			**  bad idea, but it's up to you....
355c2aa98e2SPeter Wemm 			*/
356c2aa98e2SPeter Wemm 
35706f25ae9SGregory Neil Shapiro 			if (TryNullMXList)
35806f25ae9SGregory Neil Shapiro 			{
359602a2b1bSGregory Neil Shapiro 				SM_SET_H_ERRNO(0);
36006f25ae9SGregory Neil Shapiro 				errno = 0;
36106f25ae9SGregory Neil Shapiro 				h = sm_gethostbyname(host, AF_INET);
36206f25ae9SGregory Neil Shapiro 				if (h == NULL)
36306f25ae9SGregory Neil Shapiro 				{
36406f25ae9SGregory Neil Shapiro 					if (errno == ETIMEDOUT ||
36506f25ae9SGregory Neil Shapiro 					    h_errno == TRY_AGAIN ||
36606f25ae9SGregory Neil Shapiro 					    (errno == ECONNREFUSED &&
36706f25ae9SGregory Neil Shapiro 					     UseNameServer))
36806f25ae9SGregory Neil Shapiro 					{
36906f25ae9SGregory Neil Shapiro 						*rcode = EX_TEMPFAIL;
37006f25ae9SGregory Neil Shapiro 						return -1;
37106f25ae9SGregory Neil Shapiro 					}
37206f25ae9SGregory Neil Shapiro # if NETINET6
373602a2b1bSGregory Neil Shapiro 					SM_SET_H_ERRNO(0);
37406f25ae9SGregory Neil Shapiro 					errno = 0;
37506f25ae9SGregory Neil Shapiro 					h = sm_gethostbyname(host, AF_INET6);
37606f25ae9SGregory Neil Shapiro 					if (h == NULL &&
37706f25ae9SGregory Neil Shapiro 					    (errno == ETIMEDOUT ||
37806f25ae9SGregory Neil Shapiro 					     h_errno == TRY_AGAIN ||
37906f25ae9SGregory Neil Shapiro 					     (errno == ECONNREFUSED &&
38006f25ae9SGregory Neil Shapiro 					      UseNameServer)))
38106f25ae9SGregory Neil Shapiro 					{
38206f25ae9SGregory Neil Shapiro 						*rcode = EX_TEMPFAIL;
38306f25ae9SGregory Neil Shapiro 						return -1;
38406f25ae9SGregory Neil Shapiro 					}
38506f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
38606f25ae9SGregory Neil Shapiro 				}
38706f25ae9SGregory Neil Shapiro 			}
38806f25ae9SGregory Neil Shapiro 
38906f25ae9SGregory Neil Shapiro 			if (h == NULL)
39006f25ae9SGregory Neil Shapiro 			{
391c2aa98e2SPeter Wemm 				*rcode = EX_CONFIG;
392c2aa98e2SPeter Wemm 				syserr("MX list for %s points back to %s",
393c2aa98e2SPeter Wemm 				       host, MyHostName);
394c2aa98e2SPeter Wemm 				return -1;
395c2aa98e2SPeter Wemm 			}
396193538b7SGregory Neil Shapiro # if _FFR_FREEHOSTENT && NETINET6
397193538b7SGregory Neil Shapiro 			freehostent(h);
398193538b7SGregory Neil Shapiro 			hp = NULL;
399193538b7SGregory Neil Shapiro # endif /* _FFR_FREEHOSTENT && NETINET6 */
40006f25ae9SGregory Neil Shapiro 		}
401c2aa98e2SPeter Wemm 		if (strlen(host) >= (SIZE_T) sizeof MXHostBuf)
402c2aa98e2SPeter Wemm 		{
403c2aa98e2SPeter Wemm 			*rcode = EX_CONFIG;
404c2aa98e2SPeter Wemm 			syserr("Host name %s too long",
405c2aa98e2SPeter Wemm 			       shortenstring(host, MAXSHORTSTR));
406c2aa98e2SPeter Wemm 			return -1;
407c2aa98e2SPeter Wemm 		}
408c2aa98e2SPeter Wemm 		snprintf(MXHostBuf, sizeof MXHostBuf, "%s", host);
409c2aa98e2SPeter Wemm 		mxhosts[0] = MXHostBuf;
41006f25ae9SGregory Neil Shapiro 		prefs[0] = 0;
411c2aa98e2SPeter Wemm 		if (host[0] == '[')
412c2aa98e2SPeter Wemm 		{
413c2aa98e2SPeter Wemm 			register char *p;
41406f25ae9SGregory Neil Shapiro # if NETINET6
41506f25ae9SGregory Neil Shapiro 			struct sockaddr_in6 tmp6;
41606f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
417c2aa98e2SPeter Wemm 
418c2aa98e2SPeter Wemm 			/* this may be an MX suppression-style address */
419c2aa98e2SPeter Wemm 			p = strchr(MXHostBuf, ']');
420c2aa98e2SPeter Wemm 			if (p != NULL)
421c2aa98e2SPeter Wemm 			{
422c2aa98e2SPeter Wemm 				*p = '\0';
42306f25ae9SGregory Neil Shapiro 
424c2aa98e2SPeter Wemm 				if (inet_addr(&MXHostBuf[1]) != INADDR_NONE)
425c2aa98e2SPeter Wemm 				{
426c2aa98e2SPeter Wemm 					nmx++;
427c2aa98e2SPeter Wemm 					*p = ']';
428c2aa98e2SPeter Wemm 				}
42906f25ae9SGregory Neil Shapiro # if NETINET6
43006f25ae9SGregory Neil Shapiro 				else if (inet_pton(AF_INET6, &MXHostBuf[1],
43106f25ae9SGregory Neil Shapiro 						   &tmp6.sin6_addr) == 1)
43206f25ae9SGregory Neil Shapiro 				{
43306f25ae9SGregory Neil Shapiro 					nmx++;
43406f25ae9SGregory Neil Shapiro 					*p = ']';
43506f25ae9SGregory Neil Shapiro 				}
43606f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
437c2aa98e2SPeter Wemm 				else
438c2aa98e2SPeter Wemm 				{
439c2aa98e2SPeter Wemm 					trycanon = TRUE;
440c2aa98e2SPeter Wemm 					mxhosts[0]++;
441c2aa98e2SPeter Wemm 				}
442c2aa98e2SPeter Wemm 			}
443c2aa98e2SPeter Wemm 		}
444c2aa98e2SPeter Wemm 		if (trycanon &&
445c2aa98e2SPeter Wemm 		    getcanonname(mxhosts[0], sizeof MXHostBuf - 2, FALSE))
446c2aa98e2SPeter Wemm 		{
447c2aa98e2SPeter Wemm 			bp = &MXHostBuf[strlen(MXHostBuf)];
448c2aa98e2SPeter Wemm 			if (bp[-1] != '.')
449c2aa98e2SPeter Wemm 			{
450c2aa98e2SPeter Wemm 				*bp++ = '.';
451c2aa98e2SPeter Wemm 				*bp = '\0';
452c2aa98e2SPeter Wemm 			}
453c2aa98e2SPeter Wemm 			nmx = 1;
454c2aa98e2SPeter Wemm 		}
455c2aa98e2SPeter Wemm 	}
456c2aa98e2SPeter Wemm 
457c2aa98e2SPeter Wemm 	/* if we have a default lowest preference, include that */
458c2aa98e2SPeter Wemm 	if (fallbackMX != NULL && !seenlocal)
45906f25ae9SGregory Neil Shapiro 	{
46006f25ae9SGregory Neil Shapiro 		if (nmx > 0)
46106f25ae9SGregory Neil Shapiro 			prefs[nmx] = prefs[nmx - 1] + 1;
46206f25ae9SGregory Neil Shapiro 		else
46306f25ae9SGregory Neil Shapiro 			prefs[nmx] = 0;
464c2aa98e2SPeter Wemm 		mxhosts[nmx++] = fallbackMX;
46506f25ae9SGregory Neil Shapiro 	}
466c2aa98e2SPeter Wemm 
46706f25ae9SGregory Neil Shapiro 	return nmx;
468c2aa98e2SPeter Wemm }
469c2aa98e2SPeter Wemm /*
470c2aa98e2SPeter Wemm **  MXRAND -- create a randomizer for equal MX preferences
471c2aa98e2SPeter Wemm **
472c2aa98e2SPeter Wemm **	If two MX hosts have equal preferences we want to randomize
473c2aa98e2SPeter Wemm **	the selection.  But in order for signatures to be the same,
474c2aa98e2SPeter Wemm **	we need to randomize the same way each time.  This function
475c2aa98e2SPeter Wemm **	computes a pseudo-random hash function from the host name.
476c2aa98e2SPeter Wemm **
477c2aa98e2SPeter Wemm **	Parameters:
478c2aa98e2SPeter Wemm **		host -- the name of the host.
479c2aa98e2SPeter Wemm **
480c2aa98e2SPeter Wemm **	Returns:
481c2aa98e2SPeter Wemm **		A random but repeatable value based on the host name.
482c2aa98e2SPeter Wemm **
483c2aa98e2SPeter Wemm **	Side Effects:
484c2aa98e2SPeter Wemm **		none.
485c2aa98e2SPeter Wemm */
486c2aa98e2SPeter Wemm 
48706f25ae9SGregory Neil Shapiro static int
488c2aa98e2SPeter Wemm mxrand(host)
489c2aa98e2SPeter Wemm 	register char *host;
490c2aa98e2SPeter Wemm {
491c2aa98e2SPeter Wemm 	int hfunc;
492c2aa98e2SPeter Wemm 	static unsigned int seed;
493c2aa98e2SPeter Wemm 
494c2aa98e2SPeter Wemm 	if (seed == 0)
495c2aa98e2SPeter Wemm 	{
496c2aa98e2SPeter Wemm 		seed = (int) curtime() & 0xffff;
497c2aa98e2SPeter Wemm 		if (seed == 0)
498c2aa98e2SPeter Wemm 			seed++;
499c2aa98e2SPeter Wemm 	}
500c2aa98e2SPeter Wemm 
501c2aa98e2SPeter Wemm 	if (tTd(17, 9))
50206f25ae9SGregory Neil Shapiro 		dprintf("mxrand(%s)", host);
503c2aa98e2SPeter Wemm 
504c2aa98e2SPeter Wemm 	hfunc = seed;
505c2aa98e2SPeter Wemm 	while (*host != '\0')
506c2aa98e2SPeter Wemm 	{
507c2aa98e2SPeter Wemm 		int c = *host++;
508c2aa98e2SPeter Wemm 
509c2aa98e2SPeter Wemm 		if (isascii(c) && isupper(c))
510c2aa98e2SPeter Wemm 			c = tolower(c);
511c2aa98e2SPeter Wemm 		hfunc = ((hfunc << 1) ^ c) % 2003;
512c2aa98e2SPeter Wemm 	}
513c2aa98e2SPeter Wemm 
514c2aa98e2SPeter Wemm 	hfunc &= 0xff;
515c2aa98e2SPeter Wemm 	hfunc++;
516c2aa98e2SPeter Wemm 
517c2aa98e2SPeter Wemm 	if (tTd(17, 9))
51806f25ae9SGregory Neil Shapiro 		dprintf(" = %d\n", hfunc);
519c2aa98e2SPeter Wemm 	return hfunc;
520c2aa98e2SPeter Wemm }
521c2aa98e2SPeter Wemm /*
522c2aa98e2SPeter Wemm **  BESTMX -- find the best MX for a name
523c2aa98e2SPeter Wemm **
524c2aa98e2SPeter Wemm **	This is really a hack, but I don't see any obvious way
525c2aa98e2SPeter Wemm **	to generalize it at the moment.
526c2aa98e2SPeter Wemm */
527c2aa98e2SPeter Wemm 
528c2aa98e2SPeter Wemm /* ARGSUSED3 */
529c2aa98e2SPeter Wemm char *
530c2aa98e2SPeter Wemm bestmx_map_lookup(map, name, av, statp)
531c2aa98e2SPeter Wemm 	MAP *map;
532c2aa98e2SPeter Wemm 	char *name;
533c2aa98e2SPeter Wemm 	char **av;
534c2aa98e2SPeter Wemm 	int *statp;
535c2aa98e2SPeter Wemm {
536c2aa98e2SPeter Wemm 	int nmx;
537c2aa98e2SPeter Wemm 	int saveopts = _res.options;
538c2aa98e2SPeter Wemm 	int i, len = 0;
539c2aa98e2SPeter Wemm 	char *p;
540c2aa98e2SPeter Wemm 	char *mxhosts[MAXMXHOSTS + 1];
541065a643dSPeter Wemm 	char buf[PSBUFSIZE / 2];
542c2aa98e2SPeter Wemm 
543c2aa98e2SPeter Wemm 	_res.options &= ~(RES_DNSRCH|RES_DEFNAMES);
54406f25ae9SGregory Neil Shapiro 	nmx = getmxrr(name, mxhosts, NULL, FALSE, statp);
545c2aa98e2SPeter Wemm 	_res.options = saveopts;
546c2aa98e2SPeter Wemm 	if (nmx <= 0)
547c2aa98e2SPeter Wemm 		return NULL;
548c2aa98e2SPeter Wemm 	if (bitset(MF_MATCHONLY, map->map_mflags))
549c2aa98e2SPeter Wemm 		return map_rewrite(map, name, strlen(name), NULL);
550c2aa98e2SPeter Wemm 	if ((map->map_coldelim == '\0') || (nmx == 1))
551c2aa98e2SPeter Wemm 		return map_rewrite(map, mxhosts[0], strlen(mxhosts[0]), av);
552c2aa98e2SPeter Wemm 
553c2aa98e2SPeter Wemm 	/*
554c2aa98e2SPeter Wemm 	**  We were given a -z flag (return all MXs) and there are multiple
555c2aa98e2SPeter Wemm 	**  ones.  We need to build them all into a list.
556c2aa98e2SPeter Wemm 	*/
557c2aa98e2SPeter Wemm 	p = buf;
558c2aa98e2SPeter Wemm 	for (i = 0; i < nmx; i++)
559c2aa98e2SPeter Wemm 	{
560c2aa98e2SPeter Wemm 		int slen;
561c2aa98e2SPeter Wemm 
562c2aa98e2SPeter Wemm 		if (strchr(mxhosts[i], map->map_coldelim) != NULL)
563c2aa98e2SPeter Wemm 		{
564c2aa98e2SPeter Wemm 			syserr("bestmx_map_lookup: MX host %.64s includes map delimiter character 0x%02X",
565c2aa98e2SPeter Wemm 			       mxhosts[i], map->map_coldelim);
566c2aa98e2SPeter Wemm 			return NULL;
567c2aa98e2SPeter Wemm 		}
568c2aa98e2SPeter Wemm 		slen = strlen(mxhosts[i]);
569c2aa98e2SPeter Wemm 		if (len + slen + 2 > sizeof buf)
570c2aa98e2SPeter Wemm 			break;
571c2aa98e2SPeter Wemm 		if (i > 0)
572c2aa98e2SPeter Wemm 		{
573c2aa98e2SPeter Wemm 			*p++ = map->map_coldelim;
574c2aa98e2SPeter Wemm 			len++;
575c2aa98e2SPeter Wemm 		}
57606f25ae9SGregory Neil Shapiro 		(void) strlcpy(p, mxhosts[i], sizeof buf - len);
577c2aa98e2SPeter Wemm 		p += slen;
578c2aa98e2SPeter Wemm 		len += slen;
579c2aa98e2SPeter Wemm 	}
580c2aa98e2SPeter Wemm 	return map_rewrite(map, buf, len, av);
581c2aa98e2SPeter Wemm }
582c2aa98e2SPeter Wemm /*
583c2aa98e2SPeter Wemm **  DNS_GETCANONNAME -- get the canonical name for named host using DNS
584c2aa98e2SPeter Wemm **
585c2aa98e2SPeter Wemm **	This algorithm tries to be smart about wildcard MX records.
586c2aa98e2SPeter Wemm **	This is hard to do because DNS doesn't tell is if we matched
587c2aa98e2SPeter Wemm **	against a wildcard or a specific MX.
588c2aa98e2SPeter Wemm **
589c2aa98e2SPeter Wemm **	We always prefer A & CNAME records, since these are presumed
590c2aa98e2SPeter Wemm **	to be specific.
591c2aa98e2SPeter Wemm **
592c2aa98e2SPeter Wemm **	If we match an MX in one pass and lose it in the next, we use
593c2aa98e2SPeter Wemm **	the old one.  For example, consider an MX matching *.FOO.BAR.COM.
594c2aa98e2SPeter Wemm **	A hostname bletch.foo.bar.com will match against this MX, but
595c2aa98e2SPeter Wemm **	will stop matching when we try bletch.bar.com -- so we know
596c2aa98e2SPeter Wemm **	that bletch.foo.bar.com must have been right.  This fails if
597c2aa98e2SPeter Wemm **	there was also an MX record matching *.BAR.COM, but there are
598c2aa98e2SPeter Wemm **	some things that just can't be fixed.
599c2aa98e2SPeter Wemm **
600c2aa98e2SPeter Wemm **	Parameters:
601c2aa98e2SPeter Wemm **		host -- a buffer containing the name of the host.
602c2aa98e2SPeter Wemm **			This is a value-result parameter.
603c2aa98e2SPeter Wemm **		hbsize -- the size of the host buffer.
604c2aa98e2SPeter Wemm **		trymx -- if set, try MX records as well as A and CNAME.
605c2aa98e2SPeter Wemm **		statp -- pointer to place to store status.
606c2aa98e2SPeter Wemm **
607c2aa98e2SPeter Wemm **	Returns:
608c2aa98e2SPeter Wemm **		TRUE -- if the host matched.
609c2aa98e2SPeter Wemm **		FALSE -- otherwise.
610c2aa98e2SPeter Wemm */
611c2aa98e2SPeter Wemm 
612c2aa98e2SPeter Wemm bool
613c2aa98e2SPeter Wemm dns_getcanonname(host, hbsize, trymx, statp)
614c2aa98e2SPeter Wemm 	char *host;
615c2aa98e2SPeter Wemm 	int hbsize;
616c2aa98e2SPeter Wemm 	bool trymx;
617c2aa98e2SPeter Wemm 	int *statp;
618c2aa98e2SPeter Wemm {
619c2aa98e2SPeter Wemm 	register u_char *eom, *ap;
620c2aa98e2SPeter Wemm 	register char *cp;
621c2aa98e2SPeter Wemm 	register int n;
622c2aa98e2SPeter Wemm 	HEADER *hp;
623c2aa98e2SPeter Wemm 	querybuf answer;
624c2aa98e2SPeter Wemm 	int ancount, qdcount;
625c2aa98e2SPeter Wemm 	int ret;
626c2aa98e2SPeter Wemm 	char **domain;
627c2aa98e2SPeter Wemm 	int type;
628c2aa98e2SPeter Wemm 	char **dp;
629c2aa98e2SPeter Wemm 	char *mxmatch;
630c2aa98e2SPeter Wemm 	bool amatch;
631c2aa98e2SPeter Wemm 	bool gotmx = FALSE;
632c2aa98e2SPeter Wemm 	int qtype;
633c2aa98e2SPeter Wemm 	int loopcnt;
634c2aa98e2SPeter Wemm 	char *xp;
635c2aa98e2SPeter Wemm 	char nbuf[MAX(MAXPACKET, MAXDNAME*2+2)];
636c2aa98e2SPeter Wemm 	char *searchlist[MAXDNSRCH+2];
637c2aa98e2SPeter Wemm 
638c2aa98e2SPeter Wemm 	if (tTd(8, 2))
63906f25ae9SGregory Neil Shapiro 		dprintf("dns_getcanonname(%s, trymx=%d)\n", host, trymx);
640c2aa98e2SPeter Wemm 
641c2aa98e2SPeter Wemm 	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
642c2aa98e2SPeter Wemm 	{
643c2aa98e2SPeter Wemm 		*statp = EX_UNAVAILABLE;
644c2aa98e2SPeter Wemm 		return FALSE;
645c2aa98e2SPeter Wemm 	}
646c2aa98e2SPeter Wemm 
647193538b7SGregory Neil Shapiro 	*statp = EX_OK;
648193538b7SGregory Neil Shapiro 
649c2aa98e2SPeter Wemm 	/*
650c2aa98e2SPeter Wemm 	**  Initialize domain search list.  If there is at least one
651c2aa98e2SPeter Wemm 	**  dot in the name, search the unmodified name first so we
652c2aa98e2SPeter Wemm 	**  find "vse.CS" in Czechoslovakia instead of in the local
65306f25ae9SGregory Neil Shapiro 	**  domain (e.g., vse.CS.Berkeley.EDU).  Note that there is no
65406f25ae9SGregory Neil Shapiro 	**  longer a country named Czechoslovakia but this type of problem
65506f25ae9SGregory Neil Shapiro 	**  is still present.
656c2aa98e2SPeter Wemm 	**
657c2aa98e2SPeter Wemm 	**  Older versions of the resolver could create this
658c2aa98e2SPeter Wemm 	**  list by tearing apart the host name.
659c2aa98e2SPeter Wemm 	*/
660c2aa98e2SPeter Wemm 
661c2aa98e2SPeter Wemm 	loopcnt = 0;
662c2aa98e2SPeter Wemm cnameloop:
663c2aa98e2SPeter Wemm 	/* Check for dots in the name */
664c2aa98e2SPeter Wemm 	for (cp = host, n = 0; *cp != '\0'; cp++)
665c2aa98e2SPeter Wemm 		if (*cp == '.')
666c2aa98e2SPeter Wemm 			n++;
667c2aa98e2SPeter Wemm 
668c2aa98e2SPeter Wemm 	/*
669c2aa98e2SPeter Wemm 	**  If this is a simple name, determine whether it matches an
670c2aa98e2SPeter Wemm 	**  alias in the file defined by the environment variable HOSTALIASES.
671c2aa98e2SPeter Wemm 	*/
672c2aa98e2SPeter Wemm 	if (n == 0 && (xp = gethostalias(host)) != NULL)
673c2aa98e2SPeter Wemm 	{
674c2aa98e2SPeter Wemm 		if (loopcnt++ > MAXCNAMEDEPTH)
675c2aa98e2SPeter Wemm 		{
676c2aa98e2SPeter Wemm 			syserr("loop in ${HOSTALIASES} file");
677c2aa98e2SPeter Wemm 		}
678c2aa98e2SPeter Wemm 		else
679c2aa98e2SPeter Wemm 		{
68006f25ae9SGregory Neil Shapiro 			(void) strlcpy(host, xp, hbsize);
681c2aa98e2SPeter Wemm 			goto cnameloop;
682c2aa98e2SPeter Wemm 		}
683c2aa98e2SPeter Wemm 	}
684c2aa98e2SPeter Wemm 
685c2aa98e2SPeter Wemm 	/*
686c2aa98e2SPeter Wemm 	**  Build the search list.
687c2aa98e2SPeter Wemm 	**	If there is at least one dot in name, start with a null
688c2aa98e2SPeter Wemm 	**	domain to search the unmodified name first.
689c2aa98e2SPeter Wemm 	**	If name does not end with a dot and search up local domain
690c2aa98e2SPeter Wemm 	**	tree desired, append each local domain component to the
691c2aa98e2SPeter Wemm 	**	search list; if name contains no dots and default domain
692c2aa98e2SPeter Wemm 	**	name is desired, append default domain name to search list;
693c2aa98e2SPeter Wemm 	**	else if name ends in a dot, remove that dot.
694c2aa98e2SPeter Wemm 	*/
695c2aa98e2SPeter Wemm 
696c2aa98e2SPeter Wemm 	dp = searchlist;
697c2aa98e2SPeter Wemm 	if (n > 0)
698c2aa98e2SPeter Wemm 		*dp++ = "";
699c2aa98e2SPeter Wemm 	if (n >= 0 && *--cp != '.' && bitset(RES_DNSRCH, _res.options))
700c2aa98e2SPeter Wemm 	{
70106f25ae9SGregory Neil Shapiro 		/* make sure there are less than MAXDNSRCH domains */
70206f25ae9SGregory Neil Shapiro 		for (domain = RES_DNSRCH_VARIABLE, ret = 0;
70306f25ae9SGregory Neil Shapiro 		     *domain != NULL && ret < MAXDNSRCH;
70406f25ae9SGregory Neil Shapiro 		     ret++)
705c2aa98e2SPeter Wemm 			*dp++ = *domain++;
706c2aa98e2SPeter Wemm 	}
707c2aa98e2SPeter Wemm 	else if (n == 0 && bitset(RES_DEFNAMES, _res.options))
708c2aa98e2SPeter Wemm 	{
709c2aa98e2SPeter Wemm 		*dp++ = _res.defdname;
710c2aa98e2SPeter Wemm 	}
711c2aa98e2SPeter Wemm 	else if (*cp == '.')
712c2aa98e2SPeter Wemm 	{
713c2aa98e2SPeter Wemm 		*cp = '\0';
714c2aa98e2SPeter Wemm 	}
715c2aa98e2SPeter Wemm 	*dp = NULL;
716c2aa98e2SPeter Wemm 
717c2aa98e2SPeter Wemm 	/*
718c2aa98e2SPeter Wemm 	**  Now loop through the search list, appending each domain in turn
719c2aa98e2SPeter Wemm 	**  name and searching for a match.
720c2aa98e2SPeter Wemm 	*/
721c2aa98e2SPeter Wemm 
722c2aa98e2SPeter Wemm 	mxmatch = NULL;
723c2aa98e2SPeter Wemm 	qtype = T_ANY;
724c2aa98e2SPeter Wemm 
725c2aa98e2SPeter Wemm 	for (dp = searchlist; *dp != NULL; )
726c2aa98e2SPeter Wemm 	{
727c2aa98e2SPeter Wemm 		if (qtype == T_ANY)
728c2aa98e2SPeter Wemm 			gotmx = FALSE;
729c2aa98e2SPeter Wemm 		if (tTd(8, 5))
73006f25ae9SGregory Neil Shapiro 			dprintf("dns_getcanonname: trying %s.%s (%s)\n",
731c2aa98e2SPeter Wemm 				host, *dp,
73206f25ae9SGregory Neil Shapiro 				qtype == T_ANY ? "ANY" :
73306f25ae9SGregory Neil Shapiro # if NETINET6
73406f25ae9SGregory Neil Shapiro 				qtype == T_AAAA ? "AAAA" :
73506f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
73606f25ae9SGregory Neil Shapiro 				qtype == T_A ? "A" :
73706f25ae9SGregory Neil Shapiro 				qtype == T_MX ? "MX" :
73806f25ae9SGregory Neil Shapiro 				"???");
739193538b7SGregory Neil Shapiro 		errno = 0;
740c2aa98e2SPeter Wemm 		ret = res_querydomain(host, *dp, C_IN, qtype,
741c2aa98e2SPeter Wemm 				      answer.qb2, sizeof(answer.qb2));
742c2aa98e2SPeter Wemm 		if (ret <= 0)
743c2aa98e2SPeter Wemm 		{
744c2aa98e2SPeter Wemm 			if (tTd(8, 7))
74506f25ae9SGregory Neil Shapiro 				dprintf("\tNO: errno=%d, h_errno=%d\n",
746c2aa98e2SPeter Wemm 					errno, h_errno);
747c2aa98e2SPeter Wemm 
748c2aa98e2SPeter Wemm 			if (errno == ECONNREFUSED || h_errno == TRY_AGAIN)
749c2aa98e2SPeter Wemm 			{
750193538b7SGregory Neil Shapiro 				/*
751193538b7SGregory Neil Shapiro 				**  the name server seems to be down or
752193538b7SGregory Neil Shapiro 				**  broken.
753193538b7SGregory Neil Shapiro 				*/
754193538b7SGregory Neil Shapiro 
755602a2b1bSGregory Neil Shapiro 				SM_SET_H_ERRNO(TRY_AGAIN);
756c2aa98e2SPeter Wemm 				*statp = EX_TEMPFAIL;
75706f25ae9SGregory Neil Shapiro 
75806f25ae9SGregory Neil Shapiro 				/*
75906f25ae9SGregory Neil Shapiro 				**  If the ANY query is larger than the
76006f25ae9SGregory Neil Shapiro 				**  UDP packet size, the resolver will
76106f25ae9SGregory Neil Shapiro 				**  fall back to TCP.  However, some
76206f25ae9SGregory Neil Shapiro 				**  misconfigured firewalls block 53/TCP
76306f25ae9SGregory Neil Shapiro 				**  so the ANY lookup fails whereas an MX
76406f25ae9SGregory Neil Shapiro 				**  or A record might work.  Therefore,
76506f25ae9SGregory Neil Shapiro 				**  don't fail on ANY queries.
76606f25ae9SGregory Neil Shapiro 				**
76706f25ae9SGregory Neil Shapiro 				**  The ANY query is really meant to prime
76806f25ae9SGregory Neil Shapiro 				**  the cache so this isn't dangerous.
76906f25ae9SGregory Neil Shapiro 				*/
77006f25ae9SGregory Neil Shapiro 
771193538b7SGregory Neil Shapiro #if _FFR_WORKAROUND_BROKEN_NAMESERVERS
772602a2b1bSGregory Neil Shapiro 				if (WorkAroundBrokenAAAA)
773602a2b1bSGregory Neil Shapiro 				{
774193538b7SGregory Neil Shapiro 					/*
775193538b7SGregory Neil Shapiro 					**  Only return if not TRY_AGAIN as an
776193538b7SGregory Neil Shapiro 					**  attempt with a different qtype may
777193538b7SGregory Neil Shapiro 					**  succeed (res_querydomain() calls
778193538b7SGregory Neil Shapiro 					**  res_query() calls res_send() which
779193538b7SGregory Neil Shapiro 					**  sets errno to ETIMEDOUT if the
780193538b7SGregory Neil Shapiro 					**  nameservers could be contacted but
781193538b7SGregory Neil Shapiro 					**  didn't give an answer).
782193538b7SGregory Neil Shapiro 					*/
783193538b7SGregory Neil Shapiro 
784602a2b1bSGregory Neil Shapiro 					if (qtype != T_ANY &&
785602a2b1bSGregory Neil Shapiro 					    errno != ETIMEDOUT)
786193538b7SGregory Neil Shapiro 						return FALSE;
787602a2b1bSGregory Neil Shapiro 				}
788193538b7SGregory Neil Shapiro #else /* _FFR_WORKAROUND_BROKEN_NAMESERVERS */
78906f25ae9SGregory Neil Shapiro 				if (qtype != T_ANY)
790c2aa98e2SPeter Wemm 					return FALSE;
791193538b7SGregory Neil Shapiro #endif /* _FFR_WORKAROUND_BROKEN_NAMESERVERS */
792c2aa98e2SPeter Wemm 			}
793c2aa98e2SPeter Wemm 
794c2aa98e2SPeter Wemm 			if (h_errno != HOST_NOT_FOUND)
795c2aa98e2SPeter Wemm 			{
796c2aa98e2SPeter Wemm 				/* might have another type of interest */
797c2aa98e2SPeter Wemm 				if (qtype == T_ANY)
798c2aa98e2SPeter Wemm 				{
79906f25ae9SGregory Neil Shapiro # if NETINET6
80006f25ae9SGregory Neil Shapiro 					qtype = T_AAAA;
80106f25ae9SGregory Neil Shapiro # else /* NETINET6 */
80206f25ae9SGregory Neil Shapiro 					qtype = T_A;
80306f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
80406f25ae9SGregory Neil Shapiro 					continue;
80506f25ae9SGregory Neil Shapiro 				}
80606f25ae9SGregory Neil Shapiro # if NETINET6
80706f25ae9SGregory Neil Shapiro 				else if (qtype == T_AAAA)
80806f25ae9SGregory Neil Shapiro 				{
809c2aa98e2SPeter Wemm 					qtype = T_A;
810c2aa98e2SPeter Wemm 					continue;
811c2aa98e2SPeter Wemm 				}
81206f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
81306f25ae9SGregory Neil Shapiro 				else if (qtype == T_A && !gotmx &&
81406f25ae9SGregory Neil Shapiro 					 (trymx || **dp == '\0'))
815c2aa98e2SPeter Wemm 				{
816c2aa98e2SPeter Wemm 					qtype = T_MX;
817c2aa98e2SPeter Wemm 					continue;
818c2aa98e2SPeter Wemm 				}
819c2aa98e2SPeter Wemm 			}
820c2aa98e2SPeter Wemm 
821c2aa98e2SPeter Wemm 			/* definite no -- try the next domain */
822c2aa98e2SPeter Wemm 			dp++;
823c2aa98e2SPeter Wemm 			qtype = T_ANY;
824c2aa98e2SPeter Wemm 			continue;
825c2aa98e2SPeter Wemm 		}
826c2aa98e2SPeter Wemm 		else if (tTd(8, 7))
82706f25ae9SGregory Neil Shapiro 			dprintf("\tYES\n");
828c2aa98e2SPeter Wemm 
829c2aa98e2SPeter Wemm 		/* avoid problems after truncation in tcp packets */
830c2aa98e2SPeter Wemm 		if (ret > sizeof(answer))
831c2aa98e2SPeter Wemm 			ret = sizeof(answer);
832c2aa98e2SPeter Wemm 
833c2aa98e2SPeter Wemm 		/*
834c2aa98e2SPeter Wemm 		**  Appear to have a match.  Confirm it by searching for A or
835c2aa98e2SPeter Wemm 		**  CNAME records.  If we don't have a local domain
836c2aa98e2SPeter Wemm 		**  wild card MX record, we will accept MX as well.
837c2aa98e2SPeter Wemm 		*/
838c2aa98e2SPeter Wemm 
839c2aa98e2SPeter Wemm 		hp = (HEADER *) &answer;
840c2aa98e2SPeter Wemm 		ap = (u_char *) &answer + HFIXEDSZ;
841c2aa98e2SPeter Wemm 		eom = (u_char *) &answer + ret;
842c2aa98e2SPeter Wemm 
843c2aa98e2SPeter Wemm 		/* skip question part of response -- we know what we asked */
84406f25ae9SGregory Neil Shapiro 		for (qdcount = ntohs((u_short)hp->qdcount);
84506f25ae9SGregory Neil Shapiro 		     qdcount--;
84606f25ae9SGregory Neil Shapiro 		     ap += ret + QFIXEDSZ)
847c2aa98e2SPeter Wemm 		{
848c2aa98e2SPeter Wemm 			if ((ret = dn_skipname(ap, eom)) < 0)
849c2aa98e2SPeter Wemm 			{
850c2aa98e2SPeter Wemm 				if (tTd(8, 20))
85106f25ae9SGregory Neil Shapiro 					dprintf("qdcount failure (%d)\n",
85206f25ae9SGregory Neil Shapiro 						ntohs((u_short)hp->qdcount));
853c2aa98e2SPeter Wemm 				*statp = EX_SOFTWARE;
854c2aa98e2SPeter Wemm 				return FALSE;		/* ???XXX??? */
855c2aa98e2SPeter Wemm 			}
856c2aa98e2SPeter Wemm 		}
857c2aa98e2SPeter Wemm 
858c2aa98e2SPeter Wemm 		amatch = FALSE;
85906f25ae9SGregory Neil Shapiro 		for (ancount = ntohs((u_short)hp->ancount);
86006f25ae9SGregory Neil Shapiro 		     --ancount >= 0 && ap < eom;
861c2aa98e2SPeter Wemm 		     ap += n)
862c2aa98e2SPeter Wemm 		{
863c2aa98e2SPeter Wemm 			n = dn_expand((u_char *) &answer, eom, ap,
864c2aa98e2SPeter Wemm 				      (RES_UNC_T) nbuf, sizeof nbuf);
865c2aa98e2SPeter Wemm 			if (n < 0)
866c2aa98e2SPeter Wemm 				break;
867c2aa98e2SPeter Wemm 			ap += n;
868c2aa98e2SPeter Wemm 			GETSHORT(type, ap);
869c2aa98e2SPeter Wemm 			ap += INT16SZ + INT32SZ;
870c2aa98e2SPeter Wemm 			GETSHORT(n, ap);
871c2aa98e2SPeter Wemm 			switch (type)
872c2aa98e2SPeter Wemm 			{
873c2aa98e2SPeter Wemm 			  case T_MX:
874c2aa98e2SPeter Wemm 				gotmx = TRUE;
875c2aa98e2SPeter Wemm 				if (**dp != '\0' && HasWildcardMX)
876c2aa98e2SPeter Wemm 				{
877c2aa98e2SPeter Wemm 					/*
878c2aa98e2SPeter Wemm 					**  If we are using MX matches and have
879c2aa98e2SPeter Wemm 					**  not yet gotten one, save this one
880c2aa98e2SPeter Wemm 					**  but keep searching for an A or
881c2aa98e2SPeter Wemm 					**  CNAME match.
882c2aa98e2SPeter Wemm 					*/
883c2aa98e2SPeter Wemm 
884c2aa98e2SPeter Wemm 					if (trymx && mxmatch == NULL)
885c2aa98e2SPeter Wemm 						mxmatch = *dp;
886c2aa98e2SPeter Wemm 					continue;
887c2aa98e2SPeter Wemm 				}
888c2aa98e2SPeter Wemm 
889c2aa98e2SPeter Wemm 				/*
890c2aa98e2SPeter Wemm 				**  If we did not append a domain name, this
891c2aa98e2SPeter Wemm 				**  must have been a canonical name to start
892c2aa98e2SPeter Wemm 				**  with.  Even if we did append a domain name,
893c2aa98e2SPeter Wemm 				**  in the absence of a wildcard MX this must
894c2aa98e2SPeter Wemm 				**  still be a real MX match.
895c2aa98e2SPeter Wemm 				**  Such MX matches are as good as an A match,
896c2aa98e2SPeter Wemm 				**  fall through.
897c2aa98e2SPeter Wemm 				*/
89806f25ae9SGregory Neil Shapiro 				/* FALLTHROUGH */
89906f25ae9SGregory Neil Shapiro 
90006f25ae9SGregory Neil Shapiro # if NETINET6
90106f25ae9SGregory Neil Shapiro 			  case T_AAAA:
90206f25ae9SGregory Neil Shapiro 				/* Flag that a good match was found */
90306f25ae9SGregory Neil Shapiro 				amatch = TRUE;
90406f25ae9SGregory Neil Shapiro 
90506f25ae9SGregory Neil Shapiro 				/* continue in case a CNAME also exists */
90606f25ae9SGregory Neil Shapiro 				continue;
90706f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
908c2aa98e2SPeter Wemm 
909c2aa98e2SPeter Wemm 			  case T_A:
910c2aa98e2SPeter Wemm 				/* Flag that a good match was found */
911c2aa98e2SPeter Wemm 				amatch = TRUE;
912c2aa98e2SPeter Wemm 
913c2aa98e2SPeter Wemm 				/* continue in case a CNAME also exists */
914c2aa98e2SPeter Wemm 				continue;
915c2aa98e2SPeter Wemm 
916c2aa98e2SPeter Wemm 			  case T_CNAME:
917c2aa98e2SPeter Wemm 				if (DontExpandCnames)
918c2aa98e2SPeter Wemm 				{
919c2aa98e2SPeter Wemm 					/* got CNAME -- guaranteed canonical */
920c2aa98e2SPeter Wemm 					amatch = TRUE;
921c2aa98e2SPeter Wemm 					break;
922c2aa98e2SPeter Wemm 				}
923c2aa98e2SPeter Wemm 
924c2aa98e2SPeter Wemm 				if (loopcnt++ > MAXCNAMEDEPTH)
925c2aa98e2SPeter Wemm 				{
926c2aa98e2SPeter Wemm 					/*XXX should notify postmaster XXX*/
927c2aa98e2SPeter Wemm 					message("DNS failure: CNAME loop for %s",
928c2aa98e2SPeter Wemm 						host);
929c2aa98e2SPeter Wemm 					if (CurEnv->e_message == NULL)
930c2aa98e2SPeter Wemm 					{
931c2aa98e2SPeter Wemm 						char ebuf[MAXLINE];
932c2aa98e2SPeter Wemm 
933c2aa98e2SPeter Wemm 						snprintf(ebuf, sizeof ebuf,
934c2aa98e2SPeter Wemm 							"Deferred: DNS failure: CNAME loop for %.100s",
935c2aa98e2SPeter Wemm 							host);
936c2aa98e2SPeter Wemm 						CurEnv->e_message = newstr(ebuf);
937c2aa98e2SPeter Wemm 					}
938602a2b1bSGregory Neil Shapiro 					SM_SET_H_ERRNO(NO_RECOVERY);
939c2aa98e2SPeter Wemm 					*statp = EX_CONFIG;
940c2aa98e2SPeter Wemm 					return FALSE;
941c2aa98e2SPeter Wemm 				}
942c2aa98e2SPeter Wemm 
943c2aa98e2SPeter Wemm 				/* value points at name */
944c2aa98e2SPeter Wemm 				if ((ret = dn_expand((u_char *)&answer,
945c2aa98e2SPeter Wemm 				    eom, ap, (RES_UNC_T) nbuf, sizeof(nbuf))) < 0)
946c2aa98e2SPeter Wemm 					break;
94706f25ae9SGregory Neil Shapiro 				(void)strlcpy(host, nbuf, hbsize);
948c2aa98e2SPeter Wemm 
949c2aa98e2SPeter Wemm 				/*
950c2aa98e2SPeter Wemm 				**  RFC 1034 section 3.6 specifies that CNAME
951c2aa98e2SPeter Wemm 				**  should point at the canonical name -- but
952c2aa98e2SPeter Wemm 				**  urges software to try again anyway.
953c2aa98e2SPeter Wemm 				*/
954c2aa98e2SPeter Wemm 
955c2aa98e2SPeter Wemm 				goto cnameloop;
956c2aa98e2SPeter Wemm 
957c2aa98e2SPeter Wemm 			  default:
958c2aa98e2SPeter Wemm 				/* not a record of interest */
959c2aa98e2SPeter Wemm 				continue;
960c2aa98e2SPeter Wemm 			}
961c2aa98e2SPeter Wemm 		}
962c2aa98e2SPeter Wemm 
963c2aa98e2SPeter Wemm 		if (amatch)
964c2aa98e2SPeter Wemm 		{
965c2aa98e2SPeter Wemm 			/*
966c2aa98e2SPeter Wemm 			**  Got a good match -- either an A, CNAME, or an
967c2aa98e2SPeter Wemm 			**  exact MX record.  Save it and get out of here.
968c2aa98e2SPeter Wemm 			*/
969c2aa98e2SPeter Wemm 
970c2aa98e2SPeter Wemm 			mxmatch = *dp;
971c2aa98e2SPeter Wemm 			break;
972c2aa98e2SPeter Wemm 		}
973c2aa98e2SPeter Wemm 
974c2aa98e2SPeter Wemm 		/*
975c2aa98e2SPeter Wemm 		**  Nothing definitive yet.
976c2aa98e2SPeter Wemm 		**	If this was a T_ANY query, we don't really know what
977c2aa98e2SPeter Wemm 		**		was returned -- it might have been a T_NS,
978c2aa98e2SPeter Wemm 		**		for example.  Try T_A to be more specific
979c2aa98e2SPeter Wemm 		**		during the next pass.
980c2aa98e2SPeter Wemm 		**	If this was a T_A query and we haven't yet found a MX
981c2aa98e2SPeter Wemm 		**		match, try T_MX if allowed to do so.
982c2aa98e2SPeter Wemm 		**	Otherwise, try the next domain.
983c2aa98e2SPeter Wemm 		*/
984c2aa98e2SPeter Wemm 
985c2aa98e2SPeter Wemm 		if (qtype == T_ANY)
98606f25ae9SGregory Neil Shapiro 		{
98706f25ae9SGregory Neil Shapiro # if NETINET6
98806f25ae9SGregory Neil Shapiro 			qtype = T_AAAA;
98906f25ae9SGregory Neil Shapiro # else /* NETINET6 */
990c2aa98e2SPeter Wemm 			qtype = T_A;
99106f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
99206f25ae9SGregory Neil Shapiro 		}
99306f25ae9SGregory Neil Shapiro # if NETINET6
99406f25ae9SGregory Neil Shapiro 		else if (qtype == T_AAAA)
99506f25ae9SGregory Neil Shapiro 			qtype = T_A;
99606f25ae9SGregory Neil Shapiro # endif /* NETINET6 */
997065a643dSPeter Wemm 		else if (qtype == T_A && !gotmx && (trymx || **dp == '\0'))
998c2aa98e2SPeter Wemm 			qtype = T_MX;
999c2aa98e2SPeter Wemm 		else
1000c2aa98e2SPeter Wemm 		{
1001c2aa98e2SPeter Wemm 			qtype = T_ANY;
1002c2aa98e2SPeter Wemm 			dp++;
1003c2aa98e2SPeter Wemm 		}
1004c2aa98e2SPeter Wemm 	}
1005c2aa98e2SPeter Wemm 
1006c2aa98e2SPeter Wemm 	/* if nothing was found, we are done */
1007c2aa98e2SPeter Wemm 	if (mxmatch == NULL)
1008c2aa98e2SPeter Wemm 	{
1009193538b7SGregory Neil Shapiro 		if (*statp == EX_OK)
1010c2aa98e2SPeter Wemm 			*statp = EX_NOHOST;
1011c2aa98e2SPeter Wemm 		return FALSE;
1012c2aa98e2SPeter Wemm 	}
1013c2aa98e2SPeter Wemm 
1014c2aa98e2SPeter Wemm 	/*
1015c2aa98e2SPeter Wemm 	**  Create canonical name and return.
1016c2aa98e2SPeter Wemm 	**  If saved domain name is null, name was already canonical.
1017c2aa98e2SPeter Wemm 	**  Otherwise append the saved domain name.
1018c2aa98e2SPeter Wemm 	*/
1019c2aa98e2SPeter Wemm 
1020c2aa98e2SPeter Wemm 	(void) snprintf(nbuf, sizeof nbuf, "%.*s%s%.*s", MAXDNAME, host,
1021c2aa98e2SPeter Wemm 			*mxmatch == '\0' ? "" : ".",
1022c2aa98e2SPeter Wemm 			MAXDNAME, mxmatch);
102306f25ae9SGregory Neil Shapiro 	(void) strlcpy(host, nbuf, hbsize);
1024c2aa98e2SPeter Wemm 	if (tTd(8, 5))
102506f25ae9SGregory Neil Shapiro 		dprintf("dns_getcanonname: %s\n", host);
1026c2aa98e2SPeter Wemm 	*statp = EX_OK;
1027c2aa98e2SPeter Wemm 	return TRUE;
1028c2aa98e2SPeter Wemm }
1029c2aa98e2SPeter Wemm 
103006f25ae9SGregory Neil Shapiro static char *
1031c2aa98e2SPeter Wemm gethostalias(host)
1032c2aa98e2SPeter Wemm 	char *host;
1033c2aa98e2SPeter Wemm {
1034c2aa98e2SPeter Wemm 	char *fname;
1035c2aa98e2SPeter Wemm 	FILE *fp;
1036c2aa98e2SPeter Wemm 	register char *p = NULL;
103706f25ae9SGregory Neil Shapiro 	long sff = SFF_REGONLY;
1038c2aa98e2SPeter Wemm 	char buf[MAXLINE];
1039c2aa98e2SPeter Wemm 	static char hbuf[MAXDNAME];
1040c2aa98e2SPeter Wemm 
1041c2aa98e2SPeter Wemm 	if (DontLockReadFiles)
1042c2aa98e2SPeter Wemm 		sff |= SFF_NOLOCK;
1043c2aa98e2SPeter Wemm 	fname = getenv("HOSTALIASES");
1044c2aa98e2SPeter Wemm 	if (fname == NULL ||
1045c2aa98e2SPeter Wemm 	    (fp = safefopen(fname, O_RDONLY, 0, sff)) == NULL)
1046c2aa98e2SPeter Wemm 		return NULL;
1047c2aa98e2SPeter Wemm 	while (fgets(buf, sizeof buf, fp) != NULL)
1048c2aa98e2SPeter Wemm 	{
1049c2aa98e2SPeter Wemm 		for (p = buf; p != '\0' && !(isascii(*p) && isspace(*p)); p++)
1050c2aa98e2SPeter Wemm 			continue;
1051c2aa98e2SPeter Wemm 		if (*p == 0)
1052c2aa98e2SPeter Wemm 		{
1053c2aa98e2SPeter Wemm 			/* syntax error */
1054c2aa98e2SPeter Wemm 			continue;
1055c2aa98e2SPeter Wemm 		}
1056c2aa98e2SPeter Wemm 		*p++ = '\0';
1057c2aa98e2SPeter Wemm 		if (strcasecmp(buf, host) == 0)
1058c2aa98e2SPeter Wemm 			break;
1059c2aa98e2SPeter Wemm 	}
1060c2aa98e2SPeter Wemm 
1061c2aa98e2SPeter Wemm 	if (feof(fp))
1062c2aa98e2SPeter Wemm 	{
1063c2aa98e2SPeter Wemm 		/* no match */
106406f25ae9SGregory Neil Shapiro 		(void) fclose(fp);
1065c2aa98e2SPeter Wemm 		return NULL;
1066c2aa98e2SPeter Wemm 	}
106706f25ae9SGregory Neil Shapiro 	(void) fclose(fp);
1068c2aa98e2SPeter Wemm 
1069c2aa98e2SPeter Wemm 	/* got a match; extract the equivalent name */
1070c2aa98e2SPeter Wemm 	while (*p != '\0' && isascii(*p) && isspace(*p))
1071c2aa98e2SPeter Wemm 		p++;
1072c2aa98e2SPeter Wemm 	host = p;
1073c2aa98e2SPeter Wemm 	while (*p != '\0' && !(isascii(*p) && isspace(*p)))
1074c2aa98e2SPeter Wemm 		p++;
1075c2aa98e2SPeter Wemm 	*p = '\0';
107606f25ae9SGregory Neil Shapiro 	(void) strlcpy(hbuf, host, sizeof hbuf);
1077c2aa98e2SPeter Wemm 	return hbuf;
1078c2aa98e2SPeter Wemm }
1079c2aa98e2SPeter Wemm #endif /* NAMED_BIND */
1080