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domain.c (302408) domain.c (38032)
1/*
1/*
2 * Copyright (c) 1998-2004, 2006, 2010 Proofpoint, Inc. and its suppliers.
3 * All rights reserved.
2 * Copyright (c) 1998 Sendmail, Inc. All rights reserved.
4 * Copyright (c) 1986, 1995-1997 Eric P. Allman. All rights reserved.
5 * Copyright (c) 1988, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * By using this file, you agree to the terms and conditions set
9 * forth in the LICENSE file which can be found at the top level of
10 * the sendmail distribution.
11 *
12 */
13
3 * Copyright (c) 1986, 1995-1997 Eric P. Allman. All rights reserved.
4 * Copyright (c) 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * By using this file, you agree to the terms and conditions set
8 * forth in the LICENSE file which can be found at the top level of
9 * the sendmail distribution.
10 *
11 */
12
14#include <sendmail.h>
15#include "map.h"
13#include "sendmail.h"
16
14
15#ifndef lint
17#if NAMED_BIND
16#if NAMED_BIND
18SM_RCSID("@(#)$Id: domain.c,v 8.205 2013-11-22 20:51:55 ca Exp $ (with name server)")
19#else /* NAMED_BIND */
20SM_RCSID("@(#)$Id: domain.c,v 8.205 2013-11-22 20:51:55 ca Exp $ (without name server)")
21#endif /* NAMED_BIND */
17static char sccsid[] = "@(#)domain.c 8.77 (Berkeley) 6/4/98 (with name server)";
18#else
19static char sccsid[] = "@(#)domain.c 8.77 (Berkeley) 6/4/98 (without name server)";
20#endif
21#endif /* not lint */
22
23#if NAMED_BIND
24
22
23#if NAMED_BIND
24
25# include <arpa/inet.h>
25#include <errno.h>
26#include <resolv.h>
27#include <arpa/inet.h>
26
28
27
28# ifndef MXHOSTBUFSIZE
29# define MXHOSTBUFSIZE (128 * MAXMXHOSTS)
30# endif /* ! MXHOSTBUFSIZE */
31
32static char MXHostBuf[MXHOSTBUFSIZE];
33#if (MXHOSTBUFSIZE < 2) || (MXHOSTBUFSIZE >= INT_MAX/2)
34 ERROR: _MXHOSTBUFSIZE is out of range
35#endif /* (MXHOSTBUFSIZE < 2) || (MXHOSTBUFSIZE >= INT_MAX/2) */
36
37# ifndef MAXDNSRCH
38# define MAXDNSRCH 6 /* number of possible domains to search */
39# endif /* ! MAXDNSRCH */
40
41# ifndef RES_DNSRCH_VARIABLE
42# define RES_DNSRCH_VARIABLE _res.dnsrch
43# endif /* ! RES_DNSRCH_VARIABLE */
44
45# ifndef NO_DATA
46# define NO_DATA NO_ADDRESS
47# endif /* ! NO_DATA */
48
49# ifndef HFIXEDSZ
50# define HFIXEDSZ 12 /* sizeof(HEADER) */
51# endif /* ! HFIXEDSZ */
52
53# define MAXCNAMEDEPTH 10 /* maximum depth of CNAME recursion */
54
55# if defined(__RES) && (__RES >= 19940415)
56# define RES_UNC_T char *
57# else /* defined(__RES) && (__RES >= 19940415) */
58# define RES_UNC_T unsigned char *
59# endif /* defined(__RES) && (__RES >= 19940415) */
60
61static int mxrand __P((char *));
62static int fallbackmxrr __P((int, unsigned short *, char **));
63
64/*
29/*
65** GETFALLBACKMXRR -- get MX resource records for fallback MX host.
66**
67** We have to initialize this once before doing anything else.
68** Moreover, we have to repeat this from time to time to avoid
69** stale data, e.g., in persistent queue runners.
70** This should be done in a parent process so the child
71** processes have the right data.
72**
73** Parameters:
74** host -- the name of the fallback MX host.
75**
76** Returns:
77** number of MX records.
78**
79** Side Effects:
80** Populates NumFallbackMXHosts and fbhosts.
81** Sets renewal time (based on TTL).
30** The standard udp packet size PACKETSZ (512) is not sufficient for some
31** nameserver answers containing very many resource records. The resolver
32** may switch to tcp and retry if it detects udp packet overflow.
33** Also note that the resolver routines res_query and res_search return
34** the size of the *un*truncated answer in case the supplied answer buffer
35** it not big enough to accommodate the entire answer.
82*/
83
36*/
37
84int NumFallbackMXHosts = 0; /* Number of fallback MX hosts (after MX expansion) */
85static char *fbhosts[MAXMXHOSTS + 1];
38#ifndef MAXPACKET
39# define MAXPACKET 8192 /* max packet size used internally by BIND */
40#endif
86
41
87int
88getfallbackmxrr(host)
89 char *host;
42typedef union
90{
43{
91 int i, rcode;
92 int ttl;
93 static time_t renew = 0;
44 HEADER qb1;
45 u_char qb2[MAXPACKET];
46} querybuf;
94
47
95#if 0
96 /* This is currently done before this function is called. */
97 if (host == NULL || *host == '\0')
98 return 0;
99#endif /* 0 */
100 if (NumFallbackMXHosts > 0 && renew > curtime())
101 return NumFallbackMXHosts;
102 if (host[0] == '[')
103 {
104 fbhosts[0] = host;
105 NumFallbackMXHosts = 1;
106 }
107 else
108 {
109 /* free old data */
110 for (i = 0; i < NumFallbackMXHosts; i++)
111 sm_free(fbhosts[i]);
48#ifndef MXHOSTBUFSIZE
49# define MXHOSTBUFSIZE (128 * MAXMXHOSTS)
50#endif
112
51
113 /* get new data */
114 NumFallbackMXHosts = getmxrr(host, fbhosts, NULL, false,
115 &rcode, false, &ttl);
116 renew = curtime() + ttl;
117 for (i = 0; i < NumFallbackMXHosts; i++)
118 fbhosts[i] = newstr(fbhosts[i]);
119 }
120 return NumFallbackMXHosts;
121}
52static char MXHostBuf[MXHOSTBUFSIZE];
122
53
123/*
124** FALLBACKMXRR -- add MX resource records for fallback MX host to list.
125**
126** Parameters:
127** nmx -- current number of MX records.
128** prefs -- array of preferences.
129** mxhosts -- array of MX hosts (maximum size: MAXMXHOSTS)
130**
131** Returns:
132** new number of MX records.
133**
134** Side Effects:
135** If FallbackMX was set, it appends the MX records for
136** that host to mxhosts (and modifies prefs accordingly).
137*/
54#ifndef MAXDNSRCH
55# define MAXDNSRCH 6 /* number of possible domains to search */
56#endif
138
57
139static int
140fallbackmxrr(nmx, prefs, mxhosts)
141 int nmx;
142 unsigned short *prefs;
143 char **mxhosts;
144{
145 int i;
58#ifndef MAX
59# define MAX(a, b) ((a) > (b) ? (a) : (b))
60#endif
146
61
147 for (i = 0; i < NumFallbackMXHosts && nmx < MAXMXHOSTS; i++)
148 {
149 if (nmx > 0)
150 prefs[nmx] = prefs[nmx - 1] + 1;
151 else
152 prefs[nmx] = 0;
153 mxhosts[nmx++] = fbhosts[i];
154 }
155 return nmx;
156}
62#ifndef NO_DATA
63# define NO_DATA NO_ADDRESS
64#endif
157
65
158/*
66#ifndef HFIXEDSZ
67# define HFIXEDSZ 12 /* sizeof(HEADER) */
68#endif
69
70#define MAXCNAMEDEPTH 10 /* maximum depth of CNAME recursion */
71
72#if defined(__RES) && (__RES >= 19940415)
73# define RES_UNC_T char *
74#else
75# define RES_UNC_T u_char *
76#endif
77 /*
159** GETMXRR -- get MX resource records for a domain
160**
161** Parameters:
162** host -- the name of the host to MX.
163** mxhosts -- a pointer to a return buffer of MX records.
78** GETMXRR -- get MX resource records for a domain
79**
80** Parameters:
81** host -- the name of the host to MX.
82** mxhosts -- a pointer to a return buffer of MX records.
164** mxprefs -- a pointer to a return buffer of MX preferences.
165** If NULL, don't try to populate.
166** droplocalhost -- If true, all MX records less preferred
83** droplocalhost -- If TRUE, all MX records less preferred
167** than the local host (as determined by $=w) will
168** be discarded.
169** rcode -- a pointer to an EX_ status code.
84** than the local host (as determined by $=w) will
85** be discarded.
86** rcode -- a pointer to an EX_ status code.
170** tryfallback -- add also fallback MX host?
171** pttl -- pointer to return TTL (can be NULL).
172**
173** Returns:
174** The number of MX records found.
175** -1 if there is an internal failure.
176** If no MX records are found, mxhosts[0] is set to host
177** and 1 is returned.
87**
88** Returns:
89** The number of MX records found.
90** -1 if there is an internal failure.
91** If no MX records are found, mxhosts[0] is set to host
92** and 1 is returned.
178**
179** Side Effects:
180** The entries made for mxhosts point to a static array
181** MXHostBuf[MXHOSTBUFSIZE], so the data needs to be copied,
182** if it must be preserved across calls to this function.
183*/
184
185int
93*/
94
95int
186getmxrr(host, mxhosts, mxprefs, droplocalhost, rcode, tryfallback, pttl)
96getmxrr(host, mxhosts, droplocalhost, rcode)
187 char *host;
188 char **mxhosts;
97 char *host;
98 char **mxhosts;
189 unsigned short *mxprefs;
190 bool droplocalhost;
191 int *rcode;
99 bool droplocalhost;
100 int *rcode;
192 bool tryfallback;
193 int *pttl;
194{
101{
195 register unsigned char *eom, *cp;
102 register u_char *eom, *cp;
196 register int i, j, n;
197 int nmx = 0;
198 register char *bp;
199 HEADER *hp;
200 querybuf answer;
201 int ancount, qdcount, buflen;
103 register int i, j, n;
104 int nmx = 0;
105 register char *bp;
106 HEADER *hp;
107 querybuf answer;
108 int ancount, qdcount, buflen;
202 bool seenlocal = false;
203 unsigned short pref, type;
204 unsigned short localpref = 256;
205 char *fallbackMX = FallbackMX;
206 bool trycanon = false;
207 unsigned short *prefs;
208 int (*resfunc) __P((const char *, int, int, u_char *, int));
209 unsigned short prefer[MAXMXHOSTS];
210 int weight[MAXMXHOSTS];
211 int ttl = 0;
109 bool seenlocal = FALSE;
110 u_short pref, type;
111 u_short localpref = 256;
112 char *fallbackMX = FallBackMX;
113 bool trycanon = FALSE;
114 int (*resfunc)();
212 extern int res_query(), res_search();
115 extern int res_query(), res_search();
116 u_short prefer[MAXMXHOSTS];
117 int weight[MAXMXHOSTS];
118 extern int mxrand __P((char *));
213
214 if (tTd(8, 2))
119
120 if (tTd(8, 2))
215 sm_dprintf("getmxrr(%s, droplocalhost=%d)\n",
216 host, droplocalhost);
217 *rcode = EX_OK;
218 if (pttl != NULL)
219 *pttl = SM_DEFAULT_TTL;
220 if (*host == '\0')
221 return 0;
121 printf("getmxrr(%s, droplocalhost=%d)\n", host, droplocalhost);
222
122
223 if ((fallbackMX != NULL && droplocalhost &&
224 wordinclass(fallbackMX, 'w')) || !tryfallback)
123 if (fallbackMX != NULL && droplocalhost &&
124 wordinclass(fallbackMX, 'w'))
225 {
226 /* don't use fallback for this pass */
227 fallbackMX = NULL;
228 }
229
125 {
126 /* don't use fallback for this pass */
127 fallbackMX = NULL;
128 }
129
230 if (mxprefs != NULL)
231 prefs = mxprefs;
232 else
233 prefs = prefer;
130 *rcode = EX_OK;
234
235 /* efficiency hack -- numeric or non-MX lookups */
236 if (host[0] == '[')
237 goto punt;
238
239 /*
240 ** If we don't have MX records in our host switch, don't
241 ** try for MX records. Note that this really isn't "right",

--- 5 unchanged lines hidden (view full) ---

247 if (!UseNameServer)
248 goto punt;
249 if (HasWildcardMX && ConfigLevel >= 6)
250 resfunc = res_query;
251 else
252 resfunc = res_search;
253
254 errno = 0;
131
132 /* efficiency hack -- numeric or non-MX lookups */
133 if (host[0] == '[')
134 goto punt;
135
136 /*
137 ** If we don't have MX records in our host switch, don't
138 ** try for MX records. Note that this really isn't "right",

--- 5 unchanged lines hidden (view full) ---

144 if (!UseNameServer)
145 goto punt;
146 if (HasWildcardMX && ConfigLevel >= 6)
147 resfunc = res_query;
148 else
149 resfunc = res_search;
150
151 errno = 0;
255 n = (*resfunc)(host, C_IN, T_MX, (unsigned char *) &answer,
256 sizeof(answer));
152 n = (*resfunc)(host, C_IN, T_MX, (u_char *) &answer, sizeof(answer));
257 if (n < 0)
258 {
259 if (tTd(8, 1))
153 if (n < 0)
154 {
155 if (tTd(8, 1))
260 sm_dprintf("getmxrr: res_search(%s) failed (errno=%d, h_errno=%d)\n",
261 host, errno, h_errno);
156 printf("getmxrr: res_search(%s) failed (errno=%d, h_errno=%d)\n",
157 (host == NULL) ? "<NULL>" : host, errno, h_errno);
262 switch (h_errno)
263 {
264 case NO_DATA:
158 switch (h_errno)
159 {
160 case NO_DATA:
265 trycanon = true;
266 /* FALLTHROUGH */
161 trycanon = TRUE;
162 /* fall through */
267
268 case NO_RECOVERY:
269 /* no MX data on this host */
270 goto punt;
271
272 case HOST_NOT_FOUND:
163
164 case NO_RECOVERY:
165 /* no MX data on this host */
166 goto punt;
167
168 case HOST_NOT_FOUND:
273# if BROKEN_RES_SEARCH
169#if BROKEN_RES_SEARCH
274 case 0: /* Ultrix resolver retns failure w/ h_errno=0 */
170 case 0: /* Ultrix resolver retns failure w/ h_errno=0 */
275# endif /* BROKEN_RES_SEARCH */
171#endif
276 /* host doesn't exist in DNS; might be in /etc/hosts */
172 /* host doesn't exist in DNS; might be in /etc/hosts */
277 trycanon = true;
173 trycanon = TRUE;
278 *rcode = EX_NOHOST;
279 goto punt;
280
281 case TRY_AGAIN:
282 case -1:
283 /* couldn't connect to the name server */
284 if (fallbackMX != NULL)
285 {
286 /* name server is hosed -- push to fallback */
174 *rcode = EX_NOHOST;
175 goto punt;
176
177 case TRY_AGAIN:
178 case -1:
179 /* couldn't connect to the name server */
180 if (fallbackMX != NULL)
181 {
182 /* name server is hosed -- push to fallback */
287 return fallbackmxrr(nmx, prefs, mxhosts);
183 mxhosts[nmx++] = fallbackMX;
184 return nmx;
288 }
289 /* it might come up later; better queue it up */
290 *rcode = EX_TEMPFAIL;
291 break;
292
293 default:
185 }
186 /* it might come up later; better queue it up */
187 *rcode = EX_TEMPFAIL;
188 break;
189
190 default:
294 syserr("getmxrr: res_search (%s) failed with impossible h_errno (%d)",
191 syserr("getmxrr: res_search (%s) failed with impossible h_errno (%d)\n",
295 host, h_errno);
296 *rcode = EX_OSERR;
297 break;
298 }
299
300 /* irreconcilable differences */
192 host, h_errno);
193 *rcode = EX_OSERR;
194 break;
195 }
196
197 /* irreconcilable differences */
301 return -1;
198 return (-1);
302 }
303
304 /* avoid problems after truncation in tcp packets */
305 if (n > sizeof(answer))
306 n = sizeof(answer);
307
308 /* find first satisfactory answer */
309 hp = (HEADER *)&answer;
199 }
200
201 /* avoid problems after truncation in tcp packets */
202 if (n > sizeof(answer))
203 n = sizeof(answer);
204
205 /* find first satisfactory answer */
206 hp = (HEADER *)&answer;
310 cp = (unsigned char *)&answer + HFIXEDSZ;
311 eom = (unsigned char *)&answer + n;
312 for (qdcount = ntohs((unsigned short) hp->qdcount);
313 qdcount--;
314 cp += n + QFIXEDSZ)
315 {
207 cp = (u_char *)&answer + HFIXEDSZ;
208 eom = (u_char *)&answer + n;
209 for (qdcount = ntohs(hp->qdcount); qdcount--; cp += n + QFIXEDSZ)
316 if ((n = dn_skipname(cp, eom)) < 0)
317 goto punt;
210 if ((n = dn_skipname(cp, eom)) < 0)
211 goto punt;
318 }
319
320 /* NOTE: see definition of MXHostBuf! */
321 buflen = sizeof(MXHostBuf) - 1;
212 buflen = sizeof(MXHostBuf) - 1;
322 SM_ASSERT(buflen > 0);
323 bp = MXHostBuf;
213 bp = MXHostBuf;
324 ancount = ntohs((unsigned short) hp->ancount);
325
326 /* See RFC 1035 for layout of RRs. */
327 /* XXX leave room for FallbackMX ? */
214 ancount = ntohs(hp->ancount);
328 while (--ancount >= 0 && cp < eom && nmx < MAXMXHOSTS - 1)
329 {
215 while (--ancount >= 0 && cp < eom && nmx < MAXMXHOSTS - 1)
216 {
330 if ((n = dn_expand((unsigned char *)&answer, eom, cp,
331 (RES_UNC_T) bp, buflen)) < 0)
217 if ((n = dn_expand((u_char *)&answer,
218 eom, cp, (RES_UNC_T) bp, buflen)) < 0)
332 break;
333 cp += n;
334 GETSHORT(type, cp);
219 break;
220 cp += n;
221 GETSHORT(type, cp);
335 cp += INT16SZ; /* skip over class */
336 GETLONG(ttl, cp);
337 GETSHORT(n, cp); /* rdlength */
222 cp += INT16SZ + INT32SZ;
223 GETSHORT(n, cp);
338 if (type != T_MX)
339 {
340 if (tTd(8, 8) || _res.options & RES_DEBUG)
224 if (type != T_MX)
225 {
226 if (tTd(8, 8) || _res.options & RES_DEBUG)
341 sm_dprintf("unexpected answer type %d, size %d\n",
342 type, n);
227 printf("unexpected answer type %d, size %d\n",
228 type, n);
343 cp += n;
344 continue;
345 }
346 GETSHORT(pref, cp);
229 cp += n;
230 continue;
231 }
232 GETSHORT(pref, cp);
347 if ((n = dn_expand((unsigned char *)&answer, eom, cp,
233 if ((n = dn_expand((u_char *)&answer, eom, cp,
348 (RES_UNC_T) bp, buflen)) < 0)
349 break;
350 cp += n;
234 (RES_UNC_T) bp, buflen)) < 0)
235 break;
236 cp += n;
351 n = strlen(bp);
352# if 0
353 /* Can this happen? */
354 if (n == 0)
355 {
356 if (LogLevel > 4)
357 sm_syslog(LOG_ERR, NOQID,
358 "MX records for %s contain empty string",
359 host);
360 continue;
361 }
362# endif /* 0 */
363 if (wordinclass(bp, 'w'))
364 {
365 if (tTd(8, 3))
237 if (wordinclass(bp, 'w'))
238 {
239 if (tTd(8, 3))
366 sm_dprintf("found localhost (%s) in MX list, pref=%d\n",
240 printf("found localhost (%s) in MX list, pref=%d\n",
367 bp, pref);
368 if (droplocalhost)
369 {
370 if (!seenlocal || pref < localpref)
371 localpref = pref;
241 bp, pref);
242 if (droplocalhost)
243 {
244 if (!seenlocal || pref < localpref)
245 localpref = pref;
372 seenlocal = true;
246 seenlocal = TRUE;
373 continue;
374 }
375 weight[nmx] = 0;
376 }
377 else
378 weight[nmx] = mxrand(bp);
247 continue;
248 }
249 weight[nmx] = 0;
250 }
251 else
252 weight[nmx] = mxrand(bp);
379 prefs[nmx] = pref;
253 prefer[nmx] = pref;
380 mxhosts[nmx++] = bp;
254 mxhosts[nmx++] = bp;
255 n = strlen(bp);
381 bp += n;
382 if (bp[-1] != '.')
383 {
384 *bp++ = '.';
385 n++;
386 }
387 *bp++ = '\0';
256 bp += n;
257 if (bp[-1] != '.')
258 {
259 *bp++ = '.';
260 n++;
261 }
262 *bp++ = '\0';
388 if (buflen < n + 1)
389 {
390 /* don't want to wrap buflen */
391 break;
392 }
393 buflen -= n + 1;
394 }
395
263 buflen -= n + 1;
264 }
265
396 /* return only one TTL entry, that should be sufficient */
397 if (ttl > 0 && pttl != NULL)
398 *pttl = ttl;
399
400 /* sort the records */
401 for (i = 0; i < nmx; i++)
402 {
403 for (j = i + 1; j < nmx; j++)
404 {
266 /* sort the records */
267 for (i = 0; i < nmx; i++)
268 {
269 for (j = i + 1; j < nmx; j++)
270 {
405 if (prefs[i] > prefs[j] ||
406 (prefs[i] == prefs[j] && weight[i] > weight[j]))
271 if (prefer[i] > prefer[j] ||
272 (prefer[i] == prefer[j] && weight[i] > weight[j]))
407 {
408 register int temp;
409 register char *temp1;
410
273 {
274 register int temp;
275 register char *temp1;
276
411 temp = prefs[i];
412 prefs[i] = prefs[j];
413 prefs[j] = temp;
277 temp = prefer[i];
278 prefer[i] = prefer[j];
279 prefer[j] = temp;
414 temp1 = mxhosts[i];
415 mxhosts[i] = mxhosts[j];
416 mxhosts[j] = temp1;
417 temp = weight[i];
418 weight[i] = weight[j];
419 weight[j] = temp;
420 }
421 }
280 temp1 = mxhosts[i];
281 mxhosts[i] = mxhosts[j];
282 mxhosts[j] = temp1;
283 temp = weight[i];
284 weight[i] = weight[j];
285 weight[j] = temp;
286 }
287 }
422 if (seenlocal && prefs[i] >= localpref)
288 if (seenlocal && prefer[i] >= localpref)
423 {
424 /* truncate higher preference part of list */
425 nmx = i;
426 }
427 }
428
429 /* delete duplicates from list (yes, some bozos have duplicates) */
430 for (i = 0; i < nmx - 1; )
431 {
289 {
290 /* truncate higher preference part of list */
291 nmx = i;
292 }
293 }
294
295 /* delete duplicates from list (yes, some bozos have duplicates) */
296 for (i = 0; i < nmx - 1; )
297 {
432 if (sm_strcasecmp(mxhosts[i], mxhosts[i + 1]) != 0)
298 if (strcasecmp(mxhosts[i], mxhosts[i + 1]) != 0)
433 i++;
434 else
435 {
436 /* compress out duplicate */
437 for (j = i + 1; j < nmx; j++)
299 i++;
300 else
301 {
302 /* compress out duplicate */
303 for (j = i + 1; j < nmx; j++)
438 {
439 mxhosts[j] = mxhosts[j + 1];
304 mxhosts[j] = mxhosts[j + 1];
440 prefs[j] = prefs[j + 1];
441 }
442 nmx--;
443 }
444 }
445
446 if (nmx == 0)
447 {
448punt:
305 nmx--;
306 }
307 }
308
309 if (nmx == 0)
310 {
311punt:
449 if (seenlocal)
312 if (seenlocal &&
313 (!TryNullMXList || sm_gethostbyname(host) == NULL))
450 {
314 {
451 struct hostent *h = NULL;
452
453 /*
454 ** If we have deleted all MX entries, this is
455 ** an error -- we should NEVER send to a host that
456 ** has an MX, and this should have been caught
457 ** earlier in the config file.
458 **
459 ** Some sites prefer to go ahead and try the
460 ** A record anyway; that case is handled by
461 ** setting TryNullMXList. I believe this is a
462 ** bad idea, but it's up to you....
463 */
464
315 /*
316 ** If we have deleted all MX entries, this is
317 ** an error -- we should NEVER send to a host that
318 ** has an MX, and this should have been caught
319 ** earlier in the config file.
320 **
321 ** Some sites prefer to go ahead and try the
322 ** A record anyway; that case is handled by
323 ** setting TryNullMXList. I believe this is a
324 ** bad idea, but it's up to you....
325 */
326
465 if (TryNullMXList)
466 {
467 SM_SET_H_ERRNO(0);
468 errno = 0;
469 h = sm_gethostbyname(host, AF_INET);
470 if (h == NULL)
471 {
472 if (errno == ETIMEDOUT ||
473 h_errno == TRY_AGAIN ||
474 (errno == ECONNREFUSED &&
475 UseNameServer))
476 {
477 *rcode = EX_TEMPFAIL;
478 return -1;
479 }
480# if NETINET6
481 SM_SET_H_ERRNO(0);
482 errno = 0;
483 h = sm_gethostbyname(host, AF_INET6);
484 if (h == NULL &&
485 (errno == ETIMEDOUT ||
486 h_errno == TRY_AGAIN ||
487 (errno == ECONNREFUSED &&
488 UseNameServer)))
489 {
490 *rcode = EX_TEMPFAIL;
491 return -1;
492 }
493# endif /* NETINET6 */
494 }
495 }
496
497 if (h == NULL)
498 {
499 *rcode = EX_CONFIG;
500 syserr("MX list for %s points back to %s",
501 host, MyHostName);
502 return -1;
503 }
504# if NETINET6
505 freehostent(h);
506 h = NULL;
507# endif /* NETINET6 */
327 *rcode = EX_CONFIG;
328 syserr("MX list for %s points back to %s",
329 host, MyHostName);
330 return -1;
508 }
331 }
509 if (strlen(host) >= sizeof(MXHostBuf))
332 if (strlen(host) >= (SIZE_T) sizeof MXHostBuf)
510 {
511 *rcode = EX_CONFIG;
512 syserr("Host name %s too long",
513 shortenstring(host, MAXSHORTSTR));
514 return -1;
515 }
333 {
334 *rcode = EX_CONFIG;
335 syserr("Host name %s too long",
336 shortenstring(host, MAXSHORTSTR));
337 return -1;
338 }
516 (void) sm_strlcpy(MXHostBuf, host, sizeof(MXHostBuf));
339 snprintf(MXHostBuf, sizeof MXHostBuf, "%s", host);
517 mxhosts[0] = MXHostBuf;
340 mxhosts[0] = MXHostBuf;
518 prefs[0] = 0;
519 if (host[0] == '[')
520 {
521 register char *p;
341 if (host[0] == '[')
342 {
343 register char *p;
522# if NETINET6
523 struct sockaddr_in6 tmp6;
524# endif /* NETINET6 */
525
526 /* this may be an MX suppression-style address */
527 p = strchr(MXHostBuf, ']');
528 if (p != NULL)
529 {
530 *p = '\0';
344
345 /* this may be an MX suppression-style address */
346 p = strchr(MXHostBuf, ']');
347 if (p != NULL)
348 {
349 *p = '\0';
531
532 if (inet_addr(&MXHostBuf[1]) != INADDR_NONE)
533 {
534 nmx++;
535 *p = ']';
536 }
350 if (inet_addr(&MXHostBuf[1]) != INADDR_NONE)
351 {
352 nmx++;
353 *p = ']';
354 }
537# if NETINET6
538 else if (anynet_pton(AF_INET6, &MXHostBuf[1],
539 &tmp6.sin6_addr) == 1)
540 {
541 nmx++;
542 *p = ']';
543 }
544# endif /* NETINET6 */
545 else
546 {
355 else
356 {
547 trycanon = true;
357 trycanon = TRUE;
548 mxhosts[0]++;
549 }
550 }
551 }
552 if (trycanon &&
358 mxhosts[0]++;
359 }
360 }
361 }
362 if (trycanon &&
553 getcanonname(mxhosts[0], sizeof(MXHostBuf) - 2, false, pttl))
363 getcanonname(mxhosts[0], sizeof MXHostBuf - 2, FALSE))
554 {
364 {
555 /* XXX MXHostBuf == "" ? is that possible? */
556 bp = &MXHostBuf[strlen(MXHostBuf)];
557 if (bp[-1] != '.')
558 {
559 *bp++ = '.';
560 *bp = '\0';
561 }
562 nmx = 1;
563 }
564 }
565
566 /* if we have a default lowest preference, include that */
567 if (fallbackMX != NULL && !seenlocal)
365 bp = &MXHostBuf[strlen(MXHostBuf)];
366 if (bp[-1] != '.')
367 {
368 *bp++ = '.';
369 *bp = '\0';
370 }
371 nmx = 1;
372 }
373 }
374
375 /* if we have a default lowest preference, include that */
376 if (fallbackMX != NULL && !seenlocal)
568 {
569 nmx = fallbackmxrr(nmx, prefs, mxhosts);
570 }
571 return nmx;
377 mxhosts[nmx++] = fallbackMX;
378
379 return (nmx);
572}
380}
573/*
381 /*
574** MXRAND -- create a randomizer for equal MX preferences
575**
576** If two MX hosts have equal preferences we want to randomize
577** the selection. But in order for signatures to be the same,
578** we need to randomize the same way each time. This function
579** computes a pseudo-random hash function from the host name.
580**
581** Parameters:
582** host -- the name of the host.
583**
584** Returns:
585** A random but repeatable value based on the host name.
382** MXRAND -- create a randomizer for equal MX preferences
383**
384** If two MX hosts have equal preferences we want to randomize
385** the selection. But in order for signatures to be the same,
386** we need to randomize the same way each time. This function
387** computes a pseudo-random hash function from the host name.
388**
389** Parameters:
390** host -- the name of the host.
391**
392** Returns:
393** A random but repeatable value based on the host name.
394**
395** Side Effects:
396** none.
586*/
587
397*/
398
588static int
399int
589mxrand(host)
590 register char *host;
591{
592 int hfunc;
593 static unsigned int seed;
594
595 if (seed == 0)
596 {
597 seed = (int) curtime() & 0xffff;
598 if (seed == 0)
599 seed++;
600 }
601
602 if (tTd(17, 9))
400mxrand(host)
401 register char *host;
402{
403 int hfunc;
404 static unsigned int seed;
405
406 if (seed == 0)
407 {
408 seed = (int) curtime() & 0xffff;
409 if (seed == 0)
410 seed++;
411 }
412
413 if (tTd(17, 9))
603 sm_dprintf("mxrand(%s)", host);
414 printf("mxrand(%s)", host);
604
605 hfunc = seed;
606 while (*host != '\0')
607 {
608 int c = *host++;
609
610 if (isascii(c) && isupper(c))
611 c = tolower(c);
612 hfunc = ((hfunc << 1) ^ c) % 2003;
613 }
614
615 hfunc &= 0xff;
616 hfunc++;
617
618 if (tTd(17, 9))
415
416 hfunc = seed;
417 while (*host != '\0')
418 {
419 int c = *host++;
420
421 if (isascii(c) && isupper(c))
422 c = tolower(c);
423 hfunc = ((hfunc << 1) ^ c) % 2003;
424 }
425
426 hfunc &= 0xff;
427 hfunc++;
428
429 if (tTd(17, 9))
619 sm_dprintf(" = %d\n", hfunc);
430 printf(" = %d\n", hfunc);
620 return hfunc;
621}
431 return hfunc;
432}
622/*
433 /*
623** BESTMX -- find the best MX for a name
624**
625** This is really a hack, but I don't see any obvious way
626** to generalize it at the moment.
627*/
628
629/* ARGSUSED3 */
630char *
631bestmx_map_lookup(map, name, av, statp)
632 MAP *map;
633 char *name;
634 char **av;
635 int *statp;
636{
637 int nmx;
434** BESTMX -- find the best MX for a name
435**
436** This is really a hack, but I don't see any obvious way
437** to generalize it at the moment.
438*/
439
440/* ARGSUSED3 */
441char *
442bestmx_map_lookup(map, name, av, statp)
443 MAP *map;
444 char *name;
445 char **av;
446 int *statp;
447{
448 int nmx;
449 auto int rcode;
638 int saveopts = _res.options;
450 int saveopts = _res.options;
639 int i;
640 ssize_t len = 0;
641 char *result;
642 char *mxhosts[MAXMXHOSTS + 1];
643#if _FFR_BESTMX_BETTER_TRUNCATION
644 char *buf;
645#else /* _FFR_BESTMX_BETTER_TRUNCATION */
451 int i, len = 0;
646 char *p;
452 char *p;
647 char buf[PSBUFSIZE / 2];
648#endif /* _FFR_BESTMX_BETTER_TRUNCATION */
453 char *mxhosts[MAXMXHOSTS + 1];
454 char buf[MXHOSTBUFSIZE + 1];
649
650 _res.options &= ~(RES_DNSRCH|RES_DEFNAMES);
455
456 _res.options &= ~(RES_DNSRCH|RES_DEFNAMES);
651 nmx = getmxrr(name, mxhosts, NULL, false, statp, false, NULL);
457 nmx = getmxrr(name, mxhosts, FALSE, &rcode);
652 _res.options = saveopts;
653 if (nmx <= 0)
654 return NULL;
655 if (bitset(MF_MATCHONLY, map->map_mflags))
656 return map_rewrite(map, name, strlen(name), NULL);
657 if ((map->map_coldelim == '\0') || (nmx == 1))
658 return map_rewrite(map, mxhosts[0], strlen(mxhosts[0]), av);
659
660 /*
458 _res.options = saveopts;
459 if (nmx <= 0)
460 return NULL;
461 if (bitset(MF_MATCHONLY, map->map_mflags))
462 return map_rewrite(map, name, strlen(name), NULL);
463 if ((map->map_coldelim == '\0') || (nmx == 1))
464 return map_rewrite(map, mxhosts[0], strlen(mxhosts[0]), av);
465
466 /*
661 ** We were given a -z flag (return all MXs) and there are multiple
662 ** ones. We need to build them all into a list.
467 ** We were given a -z flag (return all MXs) and there are multiple
468 ** ones. We need to build them all into a list.
663 */
469 */
664
665#if _FFR_BESTMX_BETTER_TRUNCATION
666 for (i = 0; i < nmx; i++)
667 {
668 if (strchr(mxhosts[i], map->map_coldelim) != NULL)
669 {
670 syserr("bestmx_map_lookup: MX host %.64s includes map delimiter character 0x%02X",
671 mxhosts[i], map->map_coldelim);
672 return NULL;
673 }
674 len += strlen(mxhosts[i]) + 1;
675 if (len < 0)
676 {
677 len -= strlen(mxhosts[i]) + 1;
678 break;
679 }
680 }
681 buf = (char *) sm_malloc(len);
682 if (buf == NULL)
683 {
684 *statp = EX_UNAVAILABLE;
685 return NULL;
686 }
687 *buf = '\0';
688 for (i = 0; i < nmx; i++)
689 {
690 int end;
691
692 end = sm_strlcat(buf, mxhosts[i], len);
693 if (i != nmx && end + 1 < len)
694 {
695 buf[end] = map->map_coldelim;
696 buf[end + 1] = '\0';
697 }
698 }
699
700 /* Cleanly truncate for rulesets */
701 truncate_at_delim(buf, PSBUFSIZE / 2, map->map_coldelim);
702#else /* _FFR_BESTMX_BETTER_TRUNCATION */
703 p = buf;
704 for (i = 0; i < nmx; i++)
705 {
470 p = buf;
471 for (i = 0; i < nmx; i++)
472 {
706 size_t slen;
707
473 int slen;
474
708 if (strchr(mxhosts[i], map->map_coldelim) != NULL)
709 {
710 syserr("bestmx_map_lookup: MX host %.64s includes map delimiter character 0x%02X",
711 mxhosts[i], map->map_coldelim);
712 return NULL;
713 }
714 slen = strlen(mxhosts[i]);
475 if (strchr(mxhosts[i], map->map_coldelim) != NULL)
476 {
477 syserr("bestmx_map_lookup: MX host %.64s includes map delimiter character 0x%02X",
478 mxhosts[i], map->map_coldelim);
479 return NULL;
480 }
481 slen = strlen(mxhosts[i]);
715 if (len + slen + 2 > sizeof(buf))
482 if (len + slen + 2 > sizeof buf)
716 break;
717 if (i > 0)
718 {
719 *p++ = map->map_coldelim;
720 len++;
721 }
483 break;
484 if (i > 0)
485 {
486 *p++ = map->map_coldelim;
487 len++;
488 }
722 (void) sm_strlcpy(p, mxhosts[i], sizeof(buf) - len);
489 strcpy(p, mxhosts[i]);
723 p += slen;
724 len += slen;
725 }
490 p += slen;
491 len += slen;
492 }
726#endif /* _FFR_BESTMX_BETTER_TRUNCATION */
727
728 result = map_rewrite(map, buf, len, av);
729#if _FFR_BESTMX_BETTER_TRUNCATION
730 sm_free(buf);
731#endif /* _FFR_BESTMX_BETTER_TRUNCATION */
732 return result;
493 return map_rewrite(map, buf, len, av);
733}
494}
734/*
495 /*
735** DNS_GETCANONNAME -- get the canonical name for named host using DNS
736**
737** This algorithm tries to be smart about wildcard MX records.
738** This is hard to do because DNS doesn't tell is if we matched
739** against a wildcard or a specific MX.
496** DNS_GETCANONNAME -- get the canonical name for named host using DNS
497**
498** This algorithm tries to be smart about wildcard MX records.
499** This is hard to do because DNS doesn't tell is if we matched
500** against a wildcard or a specific MX.
740**
501**
741** We always prefer A & CNAME records, since these are presumed
742** to be specific.
743**
744** If we match an MX in one pass and lose it in the next, we use
745** the old one. For example, consider an MX matching *.FOO.BAR.COM.
746** A hostname bletch.foo.bar.com will match against this MX, but
747** will stop matching when we try bletch.bar.com -- so we know
748** that bletch.foo.bar.com must have been right. This fails if
749** there was also an MX record matching *.BAR.COM, but there are
750** some things that just can't be fixed.
751**
752** Parameters:
753** host -- a buffer containing the name of the host.
754** This is a value-result parameter.
755** hbsize -- the size of the host buffer.
756** trymx -- if set, try MX records as well as A and CNAME.
757** statp -- pointer to place to store status.
502** We always prefer A & CNAME records, since these are presumed
503** to be specific.
504**
505** If we match an MX in one pass and lose it in the next, we use
506** the old one. For example, consider an MX matching *.FOO.BAR.COM.
507** A hostname bletch.foo.bar.com will match against this MX, but
508** will stop matching when we try bletch.bar.com -- so we know
509** that bletch.foo.bar.com must have been right. This fails if
510** there was also an MX record matching *.BAR.COM, but there are
511** some things that just can't be fixed.
512**
513** Parameters:
514** host -- a buffer containing the name of the host.
515** This is a value-result parameter.
516** hbsize -- the size of the host buffer.
517** trymx -- if set, try MX records as well as A and CNAME.
518** statp -- pointer to place to store status.
758** pttl -- pointer to return TTL (can be NULL).
759**
760** Returns:
519**
520** Returns:
761** true -- if the host matched.
762** false -- otherwise.
521** TRUE -- if the host matched.
522** FALSE -- otherwise.
763*/
764
765bool
523*/
524
525bool
766dns_getcanonname(host, hbsize, trymx, statp, pttl)
526dns_getcanonname(host, hbsize, trymx, statp)
767 char *host;
768 int hbsize;
769 bool trymx;
770 int *statp;
527 char *host;
528 int hbsize;
529 bool trymx;
530 int *statp;
771 int *pttl;
772{
531{
773 register unsigned char *eom, *ap;
532 register u_char *eom, *ap;
774 register char *cp;
533 register char *cp;
775 register int n;
534 register int n;
776 HEADER *hp;
777 querybuf answer;
778 int ancount, qdcount;
779 int ret;
780 char **domain;
781 int type;
535 HEADER *hp;
536 querybuf answer;
537 int ancount, qdcount;
538 int ret;
539 char **domain;
540 int type;
782 int ttl = 0;
783 char **dp;
784 char *mxmatch;
785 bool amatch;
541 char **dp;
542 char *mxmatch;
543 bool amatch;
786 bool gotmx = false;
544 bool gotmx = FALSE;
787 int qtype;
545 int qtype;
788 int initial;
789 int loopcnt;
546 int loopcnt;
790 char nbuf[SM_MAX(MAXPACKET, MAXDNAME*2+2)];
791 char *searchlist[MAXDNSRCH + 2];
547 char *xp;
548 char nbuf[MAX(MAXPACKET, MAXDNAME*2+2)];
549 char *searchlist[MAXDNSRCH+2];
550 extern char *gethostalias __P((char *));
792
793 if (tTd(8, 2))
551
552 if (tTd(8, 2))
794 sm_dprintf("dns_getcanonname(%s, trymx=%d)\n", host, trymx);
553 printf("dns_getcanonname(%s, trymx=%d)\n", host, trymx);
795
796 if ((_res.options & RES_INIT) == 0 && res_init() == -1)
797 {
798 *statp = EX_UNAVAILABLE;
554
555 if ((_res.options & RES_INIT) == 0 && res_init() == -1)
556 {
557 *statp = EX_UNAVAILABLE;
799 return false;
558 return FALSE;
800 }
801
559 }
560
802 *statp = EX_OK;
803
804 /*
805 ** Initialize domain search list. If there is at least one
806 ** dot in the name, search the unmodified name first so we
807 ** find "vse.CS" in Czechoslovakia instead of in the local
561 /*
562 ** Initialize domain search list. If there is at least one
563 ** dot in the name, search the unmodified name first so we
564 ** find "vse.CS" in Czechoslovakia instead of in the local
808 ** domain (e.g., vse.CS.Berkeley.EDU). Note that there is no
809 ** longer a country named Czechoslovakia but this type of problem
810 ** is still present.
565 ** domain (e.g., vse.CS.Berkeley.EDU).
811 **
812 ** Older versions of the resolver could create this
813 ** list by tearing apart the host name.
814 */
815
816 loopcnt = 0;
817cnameloop:
818 /* Check for dots in the name */
819 for (cp = host, n = 0; *cp != '\0'; cp++)
820 if (*cp == '.')
821 n++;
822
823 /*
566 **
567 ** Older versions of the resolver could create this
568 ** list by tearing apart the host name.
569 */
570
571 loopcnt = 0;
572cnameloop:
573 /* Check for dots in the name */
574 for (cp = host, n = 0; *cp != '\0'; cp++)
575 if (*cp == '.')
576 n++;
577
578 /*
824 ** Build the search list.
579 ** If this is a simple name, determine whether it matches an
580 ** alias in the file defined by the environment variable HOSTALIASES.
581 */
582 if (n == 0 && (xp = gethostalias(host)) != NULL)
583 {
584 if (loopcnt++ > MAXCNAMEDEPTH)
585 {
586 syserr("loop in ${HOSTALIASES} file");
587 }
588 else
589 {
590 strncpy(host, xp, hbsize);
591 host[hbsize - 1] = '\0';
592 goto cnameloop;
593 }
594 }
595
596 /*
597 ** Build the search list.
825 ** If there is at least one dot in name, start with a null
826 ** domain to search the unmodified name first.
827 ** If name does not end with a dot and search up local domain
828 ** tree desired, append each local domain component to the
829 ** search list; if name contains no dots and default domain
830 ** name is desired, append default domain name to search list;
831 ** else if name ends in a dot, remove that dot.
832 */
833
834 dp = searchlist;
835 if (n > 0)
836 *dp++ = "";
837 if (n >= 0 && *--cp != '.' && bitset(RES_DNSRCH, _res.options))
838 {
598 ** If there is at least one dot in name, start with a null
599 ** domain to search the unmodified name first.
600 ** If name does not end with a dot and search up local domain
601 ** tree desired, append each local domain component to the
602 ** search list; if name contains no dots and default domain
603 ** name is desired, append default domain name to search list;
604 ** else if name ends in a dot, remove that dot.
605 */
606
607 dp = searchlist;
608 if (n > 0)
609 *dp++ = "";
610 if (n >= 0 && *--cp != '.' && bitset(RES_DNSRCH, _res.options))
611 {
839 /* make sure there are less than MAXDNSRCH domains */
840 for (domain = RES_DNSRCH_VARIABLE, ret = 0;
841 *domain != NULL && ret < MAXDNSRCH;
842 ret++)
612 for (domain = _res.dnsrch; *domain != NULL; )
843 *dp++ = *domain++;
844 }
845 else if (n == 0 && bitset(RES_DEFNAMES, _res.options))
846 {
847 *dp++ = _res.defdname;
848 }
849 else if (*cp == '.')
850 {
851 *cp = '\0';
852 }
853 *dp = NULL;
854
855 /*
856 ** Now loop through the search list, appending each domain in turn
857 ** name and searching for a match.
858 */
859
860 mxmatch = NULL;
613 *dp++ = *domain++;
614 }
615 else if (n == 0 && bitset(RES_DEFNAMES, _res.options))
616 {
617 *dp++ = _res.defdname;
618 }
619 else if (*cp == '.')
620 {
621 *cp = '\0';
622 }
623 *dp = NULL;
624
625 /*
626 ** Now loop through the search list, appending each domain in turn
627 ** name and searching for a match.
628 */
629
630 mxmatch = NULL;
861 initial = T_A;
862# if NETINET6
863 if (InetMode == AF_INET6)
864 initial = T_AAAA;
865# endif /* NETINET6 */
866 qtype = initial;
631 qtype = T_ANY;
867
868 for (dp = searchlist; *dp != NULL; )
869 {
632
633 for (dp = searchlist; *dp != NULL; )
634 {
870 if (qtype == initial)
871 gotmx = false;
635 if (qtype == T_ANY)
636 gotmx = FALSE;
872 if (tTd(8, 5))
637 if (tTd(8, 5))
873 sm_dprintf("dns_getcanonname: trying %s.%s (%s)\n",
638 printf("dns_getcanonname: trying %s.%s (%s)\n",
874 host, *dp,
639 host, *dp,
875# if NETINET6
876 qtype == T_AAAA ? "AAAA" :
877# endif /* NETINET6 */
878 qtype == T_A ? "A" :
879 qtype == T_MX ? "MX" :
880 "???");
881 errno = 0;
640 qtype == T_ANY ? "ANY" : qtype == T_A ? "A" :
641 qtype == T_MX ? "MX" : "???");
882 ret = res_querydomain(host, *dp, C_IN, qtype,
883 answer.qb2, sizeof(answer.qb2));
884 if (ret <= 0)
885 {
642 ret = res_querydomain(host, *dp, C_IN, qtype,
643 answer.qb2, sizeof(answer.qb2));
644 if (ret <= 0)
645 {
886 int save_errno = errno;
887
888 if (tTd(8, 7))
646 if (tTd(8, 7))
889 sm_dprintf("\tNO: errno=%d, h_errno=%d\n",
890 save_errno, h_errno);
647 printf("\tNO: errno=%d, h_errno=%d\n",
648 errno, h_errno);
891
649
892 if (save_errno == ECONNREFUSED || h_errno == TRY_AGAIN)
650 if (errno == ECONNREFUSED || h_errno == TRY_AGAIN)
893 {
651 {
894 /*
895 ** the name server seems to be down or broken.
896 */
897
898 SM_SET_H_ERRNO(TRY_AGAIN);
899 if (**dp == '\0')
900 {
901 if (*statp == EX_OK)
902 *statp = EX_TEMPFAIL;
903 goto nexttype;
904 }
652 /* the name server seems to be down */
653 h_errno = TRY_AGAIN;
905 *statp = EX_TEMPFAIL;
654 *statp = EX_TEMPFAIL;
906
907 if (WorkAroundBrokenAAAA)
908 {
909 /*
910 ** Only return if not TRY_AGAIN as an
911 ** attempt with a different qtype may
912 ** succeed (res_querydomain() calls
913 ** res_query() calls res_send() which
914 ** sets errno to ETIMEDOUT if the
915 ** nameservers could be contacted but
916 ** didn't give an answer).
917 */
918
919 if (save_errno != ETIMEDOUT)
920 return false;
921 }
922 else
923 return false;
655 return FALSE;
924 }
925
656 }
657
926nexttype:
927 if (h_errno != HOST_NOT_FOUND)
928 {
929 /* might have another type of interest */
658 if (h_errno != HOST_NOT_FOUND)
659 {
660 /* might have another type of interest */
930# if NETINET6
931 if (qtype == T_AAAA)
661 if (qtype == T_ANY)
932 {
933 qtype = T_A;
934 continue;
935 }
662 {
663 qtype = T_A;
664 continue;
665 }
936 else
937# endif /* NETINET6 */
938 if (qtype == T_A && !gotmx &&
939 (trymx || **dp == '\0'))
666 else if (qtype == T_A && !gotmx && trymx)
940 {
941 qtype = T_MX;
942 continue;
943 }
944 }
945
946 /* definite no -- try the next domain */
947 dp++;
667 {
668 qtype = T_MX;
669 continue;
670 }
671 }
672
673 /* definite no -- try the next domain */
674 dp++;
948 qtype = initial;
675 qtype = T_ANY;
949 continue;
950 }
951 else if (tTd(8, 7))
676 continue;
677 }
678 else if (tTd(8, 7))
952 sm_dprintf("\tYES\n");
679 printf("\tYES\n");
953
954 /* avoid problems after truncation in tcp packets */
955 if (ret > sizeof(answer))
956 ret = sizeof(answer);
680
681 /* avoid problems after truncation in tcp packets */
682 if (ret > sizeof(answer))
683 ret = sizeof(answer);
957 SM_ASSERT(ret >= 0);
958
959 /*
960 ** Appear to have a match. Confirm it by searching for A or
961 ** CNAME records. If we don't have a local domain
962 ** wild card MX record, we will accept MX as well.
963 */
964
965 hp = (HEADER *) &answer;
684
685 /*
686 ** Appear to have a match. Confirm it by searching for A or
687 ** CNAME records. If we don't have a local domain
688 ** wild card MX record, we will accept MX as well.
689 */
690
691 hp = (HEADER *) &answer;
966 ap = (unsigned char *) &answer + HFIXEDSZ;
967 eom = (unsigned char *) &answer + ret;
692 ap = (u_char *) &answer + HFIXEDSZ;
693 eom = (u_char *) &answer + ret;
968
969 /* skip question part of response -- we know what we asked */
694
695 /* skip question part of response -- we know what we asked */
970 for (qdcount = ntohs((unsigned short) hp->qdcount);
971 qdcount--;
972 ap += ret + QFIXEDSZ)
696 for (qdcount = ntohs(hp->qdcount); qdcount--; ap += ret + QFIXEDSZ)
973 {
974 if ((ret = dn_skipname(ap, eom)) < 0)
975 {
976 if (tTd(8, 20))
697 {
698 if ((ret = dn_skipname(ap, eom)) < 0)
699 {
700 if (tTd(8, 20))
977 sm_dprintf("qdcount failure (%d)\n",
978 ntohs((unsigned short) hp->qdcount));
701 printf("qdcount failure (%d)\n",
702 ntohs(hp->qdcount));
979 *statp = EX_SOFTWARE;
703 *statp = EX_SOFTWARE;
980 return false; /* ???XXX??? */
704 return FALSE; /* ???XXX??? */
981 }
982 }
983
705 }
706 }
707
984 amatch = false;
985 for (ancount = ntohs((unsigned short) hp->ancount);
986 --ancount >= 0 && ap < eom;
987 ap += n)
708 amatch = FALSE;
709 for (ancount = ntohs(hp->ancount); --ancount >= 0 && ap < eom;
710 ap += n)
988 {
711 {
989 n = dn_expand((unsigned char *) &answer, eom, ap,
990 (RES_UNC_T) nbuf, sizeof(nbuf));
712 n = dn_expand((u_char *) &answer, eom, ap,
713 (RES_UNC_T) nbuf, sizeof nbuf);
991 if (n < 0)
992 break;
993 ap += n;
994 GETSHORT(type, ap);
714 if (n < 0)
715 break;
716 ap += n;
717 GETSHORT(type, ap);
995 ap += INT16SZ; /* skip over class */
996 GETLONG(ttl, ap);
997 GETSHORT(n, ap); /* rdlength */
718 ap += INT16SZ + INT32SZ;
719 GETSHORT(n, ap);
998 switch (type)
999 {
1000 case T_MX:
720 switch (type)
721 {
722 case T_MX:
1001 gotmx = true;
723 gotmx = TRUE;
1002 if (**dp != '\0' && HasWildcardMX)
1003 {
1004 /*
1005 ** If we are using MX matches and have
1006 ** not yet gotten one, save this one
724 if (**dp != '\0' && HasWildcardMX)
725 {
726 /*
727 ** If we are using MX matches and have
728 ** not yet gotten one, save this one
1007 ** but keep searching for an A or
729 ** but keep searching for an A or
1008 ** CNAME match.
1009 */
1010
1011 if (trymx && mxmatch == NULL)
1012 mxmatch = *dp;
1013 continue;
1014 }
1015
1016 /*
1017 ** If we did not append a domain name, this
1018 ** must have been a canonical name to start
1019 ** with. Even if we did append a domain name,
1020 ** in the absence of a wildcard MX this must
1021 ** still be a real MX match.
1022 ** Such MX matches are as good as an A match,
1023 ** fall through.
1024 */
730 ** CNAME match.
731 */
732
733 if (trymx && mxmatch == NULL)
734 mxmatch = *dp;
735 continue;
736 }
737
738 /*
739 ** If we did not append a domain name, this
740 ** must have been a canonical name to start
741 ** with. Even if we did append a domain name,
742 ** in the absence of a wildcard MX this must
743 ** still be a real MX match.
744 ** Such MX matches are as good as an A match,
745 ** fall through.
746 */
1025 /* FALLTHROUGH */
1026
747
1027# if NETINET6
1028 case T_AAAA:
1029# endif /* NETINET6 */
1030 case T_A:
1031 /* Flag that a good match was found */
748 case T_A:
749 /* Flag that a good match was found */
1032 amatch = true;
750 amatch = TRUE;
1033
1034 /* continue in case a CNAME also exists */
1035 continue;
1036
1037 case T_CNAME:
1038 if (DontExpandCnames)
1039 {
1040 /* got CNAME -- guaranteed canonical */
751
752 /* continue in case a CNAME also exists */
753 continue;
754
755 case T_CNAME:
756 if (DontExpandCnames)
757 {
758 /* got CNAME -- guaranteed canonical */
1041 amatch = true;
759 amatch = TRUE;
1042 break;
1043 }
1044
1045 if (loopcnt++ > MAXCNAMEDEPTH)
1046 {
1047 /*XXX should notify postmaster XXX*/
1048 message("DNS failure: CNAME loop for %s",
1049 host);
1050 if (CurEnv->e_message == NULL)
1051 {
1052 char ebuf[MAXLINE];
1053
760 break;
761 }
762
763 if (loopcnt++ > MAXCNAMEDEPTH)
764 {
765 /*XXX should notify postmaster XXX*/
766 message("DNS failure: CNAME loop for %s",
767 host);
768 if (CurEnv->e_message == NULL)
769 {
770 char ebuf[MAXLINE];
771
1054 (void) sm_snprintf(ebuf,
1055 sizeof(ebuf),
772 snprintf(ebuf, sizeof ebuf,
1056 "Deferred: DNS failure: CNAME loop for %.100s",
1057 host);
773 "Deferred: DNS failure: CNAME loop for %.100s",
774 host);
1058 CurEnv->e_message =
1059 sm_rpool_strdup_x(
1060 CurEnv->e_rpool, ebuf);
775 CurEnv->e_message = newstr(ebuf);
1061 }
776 }
1062 SM_SET_H_ERRNO(NO_RECOVERY);
777 h_errno = NO_RECOVERY;
1063 *statp = EX_CONFIG;
778 *statp = EX_CONFIG;
1064 return false;
779 return FALSE;
1065 }
1066
1067 /* value points at name */
780 }
781
782 /* value points at name */
1068 if ((ret = dn_expand((unsigned char *)&answer,
1069 eom, ap, (RES_UNC_T) nbuf,
1070 sizeof(nbuf))) < 0)
783 if ((ret = dn_expand((u_char *)&answer,
784 eom, ap, (RES_UNC_T) nbuf, sizeof(nbuf))) < 0)
1071 break;
785 break;
1072 (void) sm_strlcpy(host, nbuf, hbsize);
786 (void)strncpy(host, nbuf, hbsize); /* XXX */
787 host[hbsize - 1] = '\0';
1073
1074 /*
1075 ** RFC 1034 section 3.6 specifies that CNAME
1076 ** should point at the canonical name -- but
1077 ** urges software to try again anyway.
1078 */
1079
1080 goto cnameloop;
1081
1082 default:
1083 /* not a record of interest */
1084 continue;
1085 }
1086 }
1087
1088 if (amatch)
1089 {
788
789 /*
790 ** RFC 1034 section 3.6 specifies that CNAME
791 ** should point at the canonical name -- but
792 ** urges software to try again anyway.
793 */
794
795 goto cnameloop;
796
797 default:
798 /* not a record of interest */
799 continue;
800 }
801 }
802
803 if (amatch)
804 {
1090 /*
805 /*
1091 ** Got a good match -- either an A, CNAME, or an
1092 ** exact MX record. Save it and get out of here.
1093 */
1094
1095 mxmatch = *dp;
1096 break;
1097 }
1098
1099 /*
1100 ** Nothing definitive yet.
806 ** Got a good match -- either an A, CNAME, or an
807 ** exact MX record. Save it and get out of here.
808 */
809
810 mxmatch = *dp;
811 break;
812 }
813
814 /*
815 ** Nothing definitive yet.
816 ** If this was a T_ANY query, we don't really know what
817 ** was returned -- it might have been a T_NS,
818 ** for example. Try T_A to be more specific
819 ** during the next pass.
1101 ** If this was a T_A query and we haven't yet found a MX
1102 ** match, try T_MX if allowed to do so.
1103 ** Otherwise, try the next domain.
1104 */
1105
820 ** If this was a T_A query and we haven't yet found a MX
821 ** match, try T_MX if allowed to do so.
822 ** Otherwise, try the next domain.
823 */
824
1106# if NETINET6
1107 if (qtype == T_AAAA)
825 if (qtype == T_ANY)
1108 qtype = T_A;
826 qtype = T_A;
1109 else
1110# endif /* NETINET6 */
1111 if (qtype == T_A && !gotmx && (trymx || **dp == '\0'))
827 else if (qtype == T_A && !gotmx && trymx)
1112 qtype = T_MX;
1113 else
1114 {
828 qtype = T_MX;
829 else
830 {
1115 qtype = initial;
831 qtype = T_ANY;
1116 dp++;
1117 }
1118 }
1119
1120 /* if nothing was found, we are done */
1121 if (mxmatch == NULL)
1122 {
832 dp++;
833 }
834 }
835
836 /* if nothing was found, we are done */
837 if (mxmatch == NULL)
838 {
1123 if (*statp == EX_OK)
1124 *statp = EX_NOHOST;
1125 return false;
839 *statp = EX_NOHOST;
840 return FALSE;
1126 }
1127
1128 /*
1129 ** Create canonical name and return.
1130 ** If saved domain name is null, name was already canonical.
1131 ** Otherwise append the saved domain name.
1132 */
1133
841 }
842
843 /*
844 ** Create canonical name and return.
845 ** If saved domain name is null, name was already canonical.
846 ** Otherwise append the saved domain name.
847 */
848
1134 (void) sm_snprintf(nbuf, sizeof(nbuf), "%.*s%s%.*s", MAXDNAME, host,
1135 *mxmatch == '\0' ? "" : ".",
1136 MAXDNAME, mxmatch);
1137 (void) sm_strlcpy(host, nbuf, hbsize);
849 (void) snprintf(nbuf, sizeof nbuf, "%.*s%s%.*s", MAXDNAME, host,
850 *mxmatch == '\0' ? "" : ".",
851 MAXDNAME, mxmatch);
852 strncpy(host, nbuf, hbsize);
853 host[hbsize - 1] = '\0';
1138 if (tTd(8, 5))
854 if (tTd(8, 5))
1139 sm_dprintf("dns_getcanonname: %s\n", host);
855 printf("dns_getcanonname: %s\n", host);
1140 *statp = EX_OK;
856 *statp = EX_OK;
857 return TRUE;
858}
1141
859
1142 /* return only one TTL entry, that should be sufficient */
1143 if (ttl > 0 && pttl != NULL)
1144 *pttl = ttl;
1145 return true;
860
861
862char *
863gethostalias(host)
864 char *host;
865{
866 char *fname;
867 FILE *fp;
868 register char *p = NULL;
869 int sff = SFF_REGONLY;
870 char buf[MAXLINE];
871 static char hbuf[MAXDNAME];
872
873 if (DontLockReadFiles)
874 sff |= SFF_NOLOCK;
875 fname = getenv("HOSTALIASES");
876 if (fname == NULL ||
877 (fp = safefopen(fname, O_RDONLY, 0, sff)) == NULL)
878 return NULL;
879 while (fgets(buf, sizeof buf, fp) != NULL)
880 {
881 for (p = buf; p != '\0' && !(isascii(*p) && isspace(*p)); p++)
882 continue;
883 if (*p == 0)
884 {
885 /* syntax error */
886 continue;
887 }
888 *p++ = '\0';
889 if (strcasecmp(buf, host) == 0)
890 break;
891 }
892
893 if (feof(fp))
894 {
895 /* no match */
896 fclose(fp);
897 return NULL;
898 }
899 fclose(fp);
900
901 /* got a match; extract the equivalent name */
902 while (*p != '\0' && isascii(*p) && isspace(*p))
903 p++;
904 host = p;
905 while (*p != '\0' && !(isascii(*p) && isspace(*p)))
906 p++;
907 *p = '\0';
908 strncpy(hbuf, host, sizeof hbuf - 1);
909 hbuf[sizeof hbuf - 1] = '\0';
910 return hbuf;
1146}
911}
912
1147#endif /* NAMED_BIND */
913#endif /* NAMED_BIND */