xref: /netbsd-src/external/mpl/bind/dist/lib/dns/xfrin.c (revision 5dd36a3bc8bf2a9dec29ceb6349550414570c447)
1 /*	$NetBSD: xfrin.c,v 1.4 2019/02/24 20:01:30 christos Exp $	*/
2 
3 /*
4  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
5  *
6  * This Source Code Form is subject to the terms of the Mozilla Public
7  * License, v. 2.0. If a copy of the MPL was not distributed with this
8  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
9  *
10  * See the COPYRIGHT file distributed with this work for additional
11  * information regarding copyright ownership.
12  */
13 
14 
15 /*! \file */
16 
17 #include <config.h>
18 
19 #include <inttypes.h>
20 #include <stdbool.h>
21 
22 #include <isc/mem.h>
23 #include <isc/print.h>
24 #include <isc/random.h>
25 #include <isc/string.h>		/* Required for HP/UX (and others?) */
26 #include <isc/task.h>
27 #include <isc/timer.h>
28 #include <isc/util.h>
29 
30 #include <dns/callbacks.h>
31 #include <dns/catz.h>
32 #include <dns/db.h>
33 #include <dns/diff.h>
34 #include <dns/events.h>
35 #include <dns/journal.h>
36 #include <dns/log.h>
37 #include <dns/message.h>
38 #include <dns/rdataclass.h>
39 #include <dns/rdatalist.h>
40 #include <dns/rdataset.h>
41 #include <dns/result.h>
42 #include <dns/soa.h>
43 #include <dns/tcpmsg.h>
44 #include <dns/timer.h>
45 #include <dns/tsig.h>
46 #include <dns/view.h>
47 #include <dns/xfrin.h>
48 #include <dns/zone.h>
49 
50 #include <dst/dst.h>
51 
52 /*
53  * Incoming AXFR and IXFR.
54  */
55 
56 /*%
57  * It would be non-sensical (or at least obtuse) to use FAIL() with an
58  * ISC_R_SUCCESS code, but the test is there to keep the Solaris compiler
59  * from complaining about "end-of-loop code not reached".
60  */
61 #define FAIL(code) \
62 	do { result = (code);					\
63 		if (result != ISC_R_SUCCESS) goto failure;	\
64 	} while (/*CONSTCOND*/0)
65 
66 #define CHECK(op) \
67 	do { result = (op);					\
68 		if (result != ISC_R_SUCCESS) goto failure;	\
69 	} while (/*CONSTCOND*/0)
70 
71 /*%
72  * The states of the *XFR state machine.  We handle both IXFR and AXFR
73  * with a single integrated state machine because they cannot be distinguished
74  * immediately - an AXFR response to an IXFR request can only be detected
75  * when the first two (2) response RRs have already been received.
76  */
77 typedef enum {
78 	XFRST_SOAQUERY,
79 	XFRST_GOTSOA,
80 	XFRST_INITIALSOA,
81 	XFRST_FIRSTDATA,
82 	XFRST_IXFR_DELSOA,
83 	XFRST_IXFR_DEL,
84 	XFRST_IXFR_ADDSOA,
85 	XFRST_IXFR_ADD,
86 	XFRST_IXFR_END,
87 	XFRST_AXFR,
88 	XFRST_AXFR_END
89 } xfrin_state_t;
90 
91 /*%
92  * Incoming zone transfer context.
93  */
94 
95 struct dns_xfrin_ctx {
96 	unsigned int		magic;
97 	isc_mem_t		*mctx;
98 	dns_zone_t		*zone;
99 
100 	int			refcount;
101 
102 	isc_task_t 		*task;
103 	isc_timer_t		*timer;
104 	isc_socketmgr_t 	*socketmgr;
105 
106 	int			connects; 	/*%< Connect in progress */
107 	int			sends;		/*%< Send in progress */
108 	int			recvs;	  	/*%< Receive in progress */
109 	bool		shuttingdown;
110 	isc_result_t		shutdown_result;
111 
112 	dns_name_t 		name; 		/*%< Name of zone to transfer */
113 	dns_rdataclass_t 	rdclass;
114 
115 	bool		checkid;
116 	dns_messageid_t		id;
117 
118 	/*%
119 	 * Requested transfer type (dns_rdatatype_axfr or
120 	 * dns_rdatatype_ixfr).  The actual transfer type
121 	 * may differ due to IXFR->AXFR fallback.
122 	 */
123 	dns_rdatatype_t 	reqtype;
124 	isc_dscp_t 		dscp;
125 
126 	isc_sockaddr_t 		masteraddr;
127 	isc_sockaddr_t		sourceaddr;
128 	isc_socket_t 		*socket;
129 
130 	/*% Buffer for IXFR/AXFR request message */
131 	isc_buffer_t 		qbuffer;
132 	unsigned char 		qbuffer_data[512];
133 
134 	/*% Incoming reply TCP message */
135 	dns_tcpmsg_t		tcpmsg;
136 	bool		tcpmsg_valid;
137 
138 	/*%
139 	 * Whether the zone originally had a database attached at the time this
140 	 * transfer context was created.  Used by maybe_free() when making
141 	 * logging decisions.
142 	 */
143 	bool			zone_had_db;
144 
145 	dns_db_t 		*db;
146 	dns_dbversion_t 	*ver;
147 	dns_diff_t 		diff;		/*%< Pending database changes */
148 	int 			difflen;	/*%< Number of pending tuples */
149 
150 	xfrin_state_t 		state;
151 	uint32_t 		end_serial;
152 	bool 		is_ixfr;
153 
154 	unsigned int		nmsg;		/*%< Number of messages recvd */
155 	unsigned int		nrecs;		/*%< Number of records recvd */
156 	uint64_t		nbytes;		/*%< Number of bytes received */
157 
158 	unsigned int		maxrecords;	/*%< The maximum number of
159 						     records set for the zone */
160 
161 	isc_time_t		start;		/*%< Start time of the transfer */
162 	isc_time_t		end;		/*%< End time of the transfer */
163 
164 	dns_tsigkey_t		*tsigkey;	/*%< Key used to create TSIG */
165 	isc_buffer_t		*lasttsig;	/*%< The last TSIG */
166 	dst_context_t		*tsigctx;	/*%< TSIG verification context */
167 	unsigned int		sincetsig;	/*%< recvd since the last TSIG */
168 	dns_xfrindone_t		done;
169 
170 	/*%
171 	 * AXFR- and IXFR-specific data.  Only one is used at a time
172 	 * according to the is_ixfr flag, so this could be a union,
173 	 * but keeping them separate makes it a bit simpler to clean
174 	 * things up when destroying the context.
175 	 */
176 	dns_rdatacallbacks_t	axfr;
177 
178 	struct {
179 		uint32_t 	request_serial;
180 		uint32_t 	current_serial;
181 		dns_journal_t	*journal;
182 
183 	} ixfr;
184 };
185 
186 #define XFRIN_MAGIC		  ISC_MAGIC('X', 'f', 'r', 'I')
187 #define VALID_XFRIN(x)		  ISC_MAGIC_VALID(x, XFRIN_MAGIC)
188 
189 /**************************************************************************/
190 /*
191  * Forward declarations.
192  */
193 
194 static isc_result_t
195 xfrin_create(isc_mem_t *mctx,
196 	     dns_zone_t *zone,
197 	     dns_db_t *db,
198 	     isc_task_t *task,
199 	     isc_timermgr_t *timermgr,
200 	     isc_socketmgr_t *socketmgr,
201 	     dns_name_t *zonename,
202 	     dns_rdataclass_t rdclass,
203 	     dns_rdatatype_t reqtype,
204 	     const isc_sockaddr_t *masteraddr,
205 	     const isc_sockaddr_t *sourceaddr,
206 	     isc_dscp_t dscp,
207 	     dns_tsigkey_t *tsigkey,
208 	     dns_xfrin_ctx_t **xfrp);
209 
210 static isc_result_t axfr_init(dns_xfrin_ctx_t *xfr);
211 static isc_result_t axfr_makedb(dns_xfrin_ctx_t *xfr, dns_db_t **dbp);
212 static isc_result_t axfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op,
213 				   dns_name_t *name, dns_ttl_t ttl,
214 				   dns_rdata_t *rdata);
215 static isc_result_t axfr_apply(dns_xfrin_ctx_t *xfr);
216 static isc_result_t axfr_commit(dns_xfrin_ctx_t *xfr);
217 static isc_result_t axfr_finalize(dns_xfrin_ctx_t *xfr);
218 
219 static isc_result_t ixfr_init(dns_xfrin_ctx_t *xfr);
220 static isc_result_t ixfr_apply(dns_xfrin_ctx_t *xfr);
221 static isc_result_t ixfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op,
222 				 dns_name_t *name, dns_ttl_t ttl,
223 				 dns_rdata_t *rdata);
224 static isc_result_t ixfr_commit(dns_xfrin_ctx_t *xfr);
225 
226 static isc_result_t xfr_rr(dns_xfrin_ctx_t *xfr, dns_name_t *name,
227 			   uint32_t ttl, dns_rdata_t *rdata);
228 
229 static isc_result_t xfrin_start(dns_xfrin_ctx_t *xfr);
230 
231 static void xfrin_connect_done(isc_task_t *task, isc_event_t *event);
232 static isc_result_t xfrin_send_request(dns_xfrin_ctx_t *xfr);
233 static void xfrin_send_done(isc_task_t *task, isc_event_t *event);
234 static void xfrin_recv_done(isc_task_t *task, isc_event_t *event);
235 static void xfrin_timeout(isc_task_t *task, isc_event_t *event);
236 
237 static void maybe_free(dns_xfrin_ctx_t *xfr);
238 
239 static void
240 xfrin_fail(dns_xfrin_ctx_t *xfr, isc_result_t result, const char *msg);
241 static isc_result_t
242 render(dns_message_t *msg, isc_mem_t *mctx, isc_buffer_t *buf);
243 
244 static void
245 xfrin_logv(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
246 	   const char *fmt, va_list ap)
247      ISC_FORMAT_PRINTF(4, 0);
248 
249 static void
250 xfrin_log1(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
251 	   const char *fmt, ...)
252      ISC_FORMAT_PRINTF(4, 5);
253 
254 static void
255 xfrin_log(dns_xfrin_ctx_t *xfr, int level, const char *fmt, ...)
256      ISC_FORMAT_PRINTF(3, 4);
257 
258 /**************************************************************************/
259 /*
260  * AXFR handling
261  */
262 
263 static isc_result_t
264 axfr_init(dns_xfrin_ctx_t *xfr) {
265 	isc_result_t result;
266 
267 	xfr->is_ixfr = false;
268 
269 	if (xfr->db != NULL)
270 		dns_db_detach(&xfr->db);
271 
272 	CHECK(axfr_makedb(xfr, &xfr->db));
273 	dns_rdatacallbacks_init(&xfr->axfr);
274 	CHECK(dns_db_beginload(xfr->db, &xfr->axfr));
275 	result = ISC_R_SUCCESS;
276  failure:
277 	return (result);
278 }
279 
280 static isc_result_t
281 axfr_makedb(dns_xfrin_ctx_t *xfr, dns_db_t **dbp) {
282 	isc_result_t result;
283 
284 	result = dns_db_create(xfr->mctx, /* XXX */
285 			       "rbt",	/* XXX guess */
286 			       &xfr->name,
287 			       dns_dbtype_zone,
288 			       xfr->rdclass,
289 			       0, NULL, /* XXX guess */
290 			       dbp);
291 	if (result == ISC_R_SUCCESS) {
292 		dns_zone_rpz_enable_db(xfr->zone, *dbp);
293 		dns_zone_catz_enable_db(xfr->zone, *dbp);
294 	}
295 	return (result);
296 }
297 
298 static isc_result_t
299 axfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op,
300 	     dns_name_t *name, dns_ttl_t ttl, dns_rdata_t *rdata)
301 {
302 	isc_result_t result;
303 
304 	dns_difftuple_t *tuple = NULL;
305 
306 	if (rdata->rdclass != xfr->rdclass)
307 		return(DNS_R_BADCLASS);
308 
309 	CHECK(dns_zone_checknames(xfr->zone, name, rdata));
310 	CHECK(dns_difftuple_create(xfr->diff.mctx, op,
311 				   name, ttl, rdata, &tuple));
312 	dns_diff_append(&xfr->diff, &tuple);
313 	if (++xfr->difflen > 100)
314 		CHECK(axfr_apply(xfr));
315 	result = ISC_R_SUCCESS;
316  failure:
317 	return (result);
318 }
319 
320 /*
321  * Store a set of AXFR RRs in the database.
322  */
323 static isc_result_t
324 axfr_apply(dns_xfrin_ctx_t *xfr) {
325 	isc_result_t result;
326 	uint64_t records;
327 
328 	CHECK(dns_diff_load(&xfr->diff, xfr->axfr.add, xfr->axfr.add_private));
329 	xfr->difflen = 0;
330 	dns_diff_clear(&xfr->diff);
331 	if (xfr->maxrecords != 0U) {
332 		result = dns_db_getsize(xfr->db, xfr->ver, &records, NULL);
333 		if (result == ISC_R_SUCCESS && records > xfr->maxrecords) {
334 			result = DNS_R_TOOMANYRECORDS;
335 			goto failure;
336 		}
337 	}
338 	result = ISC_R_SUCCESS;
339  failure:
340 	return (result);
341 }
342 
343 static isc_result_t
344 axfr_commit(dns_xfrin_ctx_t *xfr) {
345 	isc_result_t result;
346 
347 	CHECK(axfr_apply(xfr));
348 	CHECK(dns_db_endload(xfr->db, &xfr->axfr));
349 	CHECK(dns_zone_verifydb(xfr->zone, xfr->db, NULL));
350 
351 	result = ISC_R_SUCCESS;
352  failure:
353 	return (result);
354 }
355 
356 static isc_result_t
357 axfr_finalize(dns_xfrin_ctx_t *xfr) {
358 	isc_result_t result;
359 
360 	CHECK(dns_zone_replacedb(xfr->zone, xfr->db, true));
361 
362 	result = ISC_R_SUCCESS;
363  failure:
364 	return (result);
365 }
366 
367 /**************************************************************************/
368 /*
369  * IXFR handling
370  */
371 
372 static isc_result_t
373 ixfr_init(dns_xfrin_ctx_t *xfr) {
374 	isc_result_t result;
375 	char *journalfile;
376 
377 	if (xfr->reqtype != dns_rdatatype_ixfr) {
378 		xfrin_log(xfr, ISC_LOG_ERROR,
379 			  "got incremental response to AXFR request");
380 		return (DNS_R_FORMERR);
381 	}
382 
383 	xfr->is_ixfr = true;
384 	INSIST(xfr->db != NULL);
385 	xfr->difflen = 0;
386 
387 	journalfile = dns_zone_getjournal(xfr->zone);
388 	if (journalfile != NULL)
389 		CHECK(dns_journal_open(xfr->mctx, journalfile,
390 				       DNS_JOURNAL_CREATE, &xfr->ixfr.journal));
391 
392 	result = ISC_R_SUCCESS;
393  failure:
394 	return (result);
395 }
396 
397 static isc_result_t
398 ixfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op,
399 	     dns_name_t *name, dns_ttl_t ttl, dns_rdata_t *rdata)
400 {
401 	isc_result_t result;
402 	dns_difftuple_t *tuple = NULL;
403 
404 	if (rdata->rdclass != xfr->rdclass)
405 		return(DNS_R_BADCLASS);
406 
407 	if (op == DNS_DIFFOP_ADD)
408 		CHECK(dns_zone_checknames(xfr->zone, name, rdata));
409 	CHECK(dns_difftuple_create(xfr->diff.mctx, op,
410 				   name, ttl, rdata, &tuple));
411 	dns_diff_append(&xfr->diff, &tuple);
412 	if (++xfr->difflen > 100)
413 		CHECK(ixfr_apply(xfr));
414 	result = ISC_R_SUCCESS;
415  failure:
416 	return (result);
417 }
418 
419 /*
420  * Apply a set of IXFR changes to the database.
421  */
422 static isc_result_t
423 ixfr_apply(dns_xfrin_ctx_t *xfr) {
424 	isc_result_t result;
425 	uint64_t records;
426 
427 	if (xfr->ver == NULL) {
428 		CHECK(dns_db_newversion(xfr->db, &xfr->ver));
429 		if (xfr->ixfr.journal != NULL)
430 			CHECK(dns_journal_begin_transaction(xfr->ixfr.journal));
431 	}
432 	CHECK(dns_diff_apply(&xfr->diff, xfr->db, xfr->ver));
433 	if (xfr->maxrecords != 0U) {
434 		result = dns_db_getsize(xfr->db, xfr->ver, &records, NULL);
435 		if (result == ISC_R_SUCCESS && records > xfr->maxrecords) {
436 			result = DNS_R_TOOMANYRECORDS;
437 			goto failure;
438 		}
439 	}
440 	if (xfr->ixfr.journal != NULL) {
441 		result = dns_journal_writediff(xfr->ixfr.journal, &xfr->diff);
442 		if (result != ISC_R_SUCCESS)
443 			goto failure;
444 	}
445 	dns_diff_clear(&xfr->diff);
446 	xfr->difflen = 0;
447 	result = ISC_R_SUCCESS;
448  failure:
449 	return (result);
450 }
451 
452 static isc_result_t
453 ixfr_commit(dns_xfrin_ctx_t *xfr) {
454 	isc_result_t result;
455 
456 	CHECK(ixfr_apply(xfr));
457 	if (xfr->ver != NULL) {
458 		CHECK(dns_zone_verifydb(xfr->zone, xfr->db, xfr->ver));
459 		/* XXX enter ready-to-commit state here */
460 		if (xfr->ixfr.journal != NULL)
461 			CHECK(dns_journal_commit(xfr->ixfr.journal));
462 		dns_db_closeversion(xfr->db, &xfr->ver, true);
463 		dns_zone_markdirty(xfr->zone);
464 	}
465 	result = ISC_R_SUCCESS;
466  failure:
467 	return (result);
468 }
469 
470 /**************************************************************************/
471 /*
472  * Common AXFR/IXFR protocol code
473  */
474 
475 /*
476  * Handle a single incoming resource record according to the current
477  * state.
478  */
479 static isc_result_t
480 xfr_rr(dns_xfrin_ctx_t *xfr, dns_name_t *name, uint32_t ttl,
481        dns_rdata_t *rdata)
482 {
483 	isc_result_t result;
484 
485 	xfr->nrecs++;
486 
487 	if (rdata->type == dns_rdatatype_none ||
488 	    dns_rdatatype_ismeta(rdata->type))
489 		FAIL(DNS_R_FORMERR);
490 
491  redo:
492 	switch (xfr->state) {
493 	case XFRST_SOAQUERY:
494 		if (rdata->type != dns_rdatatype_soa) {
495 			xfrin_log(xfr, ISC_LOG_ERROR,
496 				  "non-SOA response to SOA query");
497 			FAIL(DNS_R_FORMERR);
498 		}
499 		xfr->end_serial = dns_soa_getserial(rdata);
500 		if (!DNS_SERIAL_GT(xfr->end_serial, xfr->ixfr.request_serial) &&
501 		    !dns_zone_isforced(xfr->zone)) {
502 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
503 				  "requested serial %u, "
504 				  "master has %u, not updating",
505 				  xfr->ixfr.request_serial, xfr->end_serial);
506 			FAIL(DNS_R_UPTODATE);
507 		}
508 		xfr->state = XFRST_GOTSOA;
509 		break;
510 
511 	case XFRST_GOTSOA:
512 		/*
513 		 * Skip other records in the answer section.
514 		 */
515 		break;
516 
517 	case XFRST_INITIALSOA:
518 		if (rdata->type != dns_rdatatype_soa) {
519 			xfrin_log(xfr, ISC_LOG_ERROR,
520 				  "first RR in zone transfer must be SOA");
521 			FAIL(DNS_R_FORMERR);
522 		}
523 		/*
524 		 * Remember the serial number in the initial SOA.
525 		 * We need it to recognize the end of an IXFR.
526 		 */
527 		xfr->end_serial = dns_soa_getserial(rdata);
528 		if (xfr->reqtype == dns_rdatatype_ixfr &&
529 		    ! DNS_SERIAL_GT(xfr->end_serial, xfr->ixfr.request_serial)
530 		    && !dns_zone_isforced(xfr->zone))
531 		{
532 			/*
533 			 * This must be the single SOA record that is
534 			 * sent when the current version on the master
535 			 * is not newer than the version in the request.
536 			 */
537 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
538 				  "requested serial %u, "
539 				  "master has %u, not updating",
540 				  xfr->ixfr.request_serial, xfr->end_serial);
541 			FAIL(DNS_R_UPTODATE);
542 		}
543 		if (xfr->reqtype == dns_rdatatype_axfr)
544 			xfr->checkid = false;
545 		xfr->state = XFRST_FIRSTDATA;
546 		break;
547 
548 	case XFRST_FIRSTDATA:
549 		/*
550 		 * If the transfer begins with one SOA record, it is an AXFR,
551 		 * if it begins with two SOAs, it is an IXFR.
552 		 */
553 		if (xfr->reqtype == dns_rdatatype_ixfr &&
554 		    rdata->type == dns_rdatatype_soa &&
555 		    xfr->ixfr.request_serial == dns_soa_getserial(rdata)) {
556 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
557 				  "got incremental response");
558 			CHECK(ixfr_init(xfr));
559 			xfr->state = XFRST_IXFR_DELSOA;
560 		} else {
561 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
562 				  "got nonincremental response");
563 			CHECK(axfr_init(xfr));
564 			xfr->state = XFRST_AXFR;
565 		}
566 		goto redo;
567 
568 	case XFRST_IXFR_DELSOA:
569 		INSIST(rdata->type == dns_rdatatype_soa);
570 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_DEL, name, ttl, rdata));
571 		xfr->state = XFRST_IXFR_DEL;
572 		break;
573 
574 	case XFRST_IXFR_DEL:
575 		if (rdata->type == dns_rdatatype_soa) {
576 			uint32_t soa_serial = dns_soa_getserial(rdata);
577 			xfr->state = XFRST_IXFR_ADDSOA;
578 			xfr->ixfr.current_serial = soa_serial;
579 			goto redo;
580 		}
581 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_DEL, name, ttl, rdata));
582 		break;
583 
584 	case XFRST_IXFR_ADDSOA:
585 		INSIST(rdata->type == dns_rdatatype_soa);
586 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_ADD, name, ttl, rdata));
587 		xfr->state = XFRST_IXFR_ADD;
588 		break;
589 
590 	case XFRST_IXFR_ADD:
591 		if (rdata->type == dns_rdatatype_soa) {
592 			uint32_t soa_serial = dns_soa_getserial(rdata);
593 			if (soa_serial == xfr->end_serial) {
594 				CHECK(ixfr_commit(xfr));
595 				xfr->state = XFRST_IXFR_END;
596 				break;
597 			} else if (soa_serial != xfr->ixfr.current_serial) {
598 				xfrin_log(xfr, ISC_LOG_ERROR,
599 					  "IXFR out of sync: "
600 					  "expected serial %u, got %u",
601 					  xfr->ixfr.current_serial, soa_serial);
602 				FAIL(DNS_R_FORMERR);
603 			} else {
604 				CHECK(ixfr_commit(xfr));
605 				xfr->state = XFRST_IXFR_DELSOA;
606 				goto redo;
607 			}
608 		}
609 		if (rdata->type == dns_rdatatype_ns &&
610 		    dns_name_iswildcard(name))
611 			FAIL(DNS_R_INVALIDNS);
612 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_ADD, name, ttl, rdata));
613 		break;
614 
615 	case XFRST_AXFR:
616 		/*
617 		 * Old BINDs sent cross class A records for non IN classes.
618 		 */
619 		if (rdata->type == dns_rdatatype_a &&
620 		    rdata->rdclass != xfr->rdclass &&
621 		    xfr->rdclass != dns_rdataclass_in)
622 			break;
623 		CHECK(axfr_putdata(xfr, DNS_DIFFOP_ADD, name, ttl, rdata));
624 		if (rdata->type == dns_rdatatype_soa) {
625 			CHECK(axfr_commit(xfr));
626 			xfr->state = XFRST_AXFR_END;
627 			break;
628 		}
629 		break;
630 	case XFRST_AXFR_END:
631 	case XFRST_IXFR_END:
632 		FAIL(DNS_R_EXTRADATA);
633 		/* NOTREACHED */
634 		/* FALLTHROUGH */
635 	default:
636 		INSIST(0);
637 		ISC_UNREACHABLE();
638 	}
639 	result = ISC_R_SUCCESS;
640  failure:
641 	return (result);
642 }
643 
644 isc_result_t
645 dns_xfrin_create(dns_zone_t *zone, dns_rdatatype_t xfrtype,
646 		 const isc_sockaddr_t *masteraddr,
647 		 const isc_sockaddr_t *sourceaddr,
648 		 isc_dscp_t dscp, dns_tsigkey_t *tsigkey, isc_mem_t *mctx,
649 		 isc_timermgr_t *timermgr, isc_socketmgr_t *socketmgr,
650 		 isc_task_t *task, dns_xfrindone_t done,
651 		 dns_xfrin_ctx_t **xfrp)
652 {
653 	dns_name_t *zonename = dns_zone_getorigin(zone);
654 	dns_xfrin_ctx_t *xfr = NULL;
655 	isc_result_t result;
656 	dns_db_t *db = NULL;
657 
658 	REQUIRE(xfrp != NULL && *xfrp == NULL);
659 
660 	(void)dns_zone_getdb(zone, &db);
661 
662 	if (xfrtype == dns_rdatatype_soa || xfrtype == dns_rdatatype_ixfr)
663 		REQUIRE(db != NULL);
664 
665 	CHECK(xfrin_create(mctx, zone, db, task, timermgr, socketmgr, zonename,
666 			   dns_zone_getclass(zone), xfrtype, masteraddr,
667 			   sourceaddr, dscp, tsigkey, &xfr));
668 
669 	if (db != NULL) {
670 		xfr->zone_had_db = true;
671 	}
672 
673 	CHECK(xfrin_start(xfr));
674 
675 	xfr->done = done;
676 	if (xfr->done != NULL)
677 		xfr->refcount++;
678 	*xfrp = xfr;
679 
680  failure:
681 	if (db != NULL)
682 		dns_db_detach(&db);
683 	if (result != ISC_R_SUCCESS) {
684 		char zonetext[DNS_NAME_MAXTEXT+32];
685 		dns_zone_name(zone, zonetext, sizeof(zonetext));
686 		xfrin_log1(ISC_LOG_ERROR, zonetext, masteraddr,
687 			   "zone transfer setup failed");
688 	}
689 	return (result);
690 }
691 
692 void
693 dns_xfrin_shutdown(dns_xfrin_ctx_t *xfr) {
694 	if (! xfr->shuttingdown)
695 		xfrin_fail(xfr, ISC_R_CANCELED, "shut down");
696 }
697 
698 void
699 dns_xfrin_attach(dns_xfrin_ctx_t *source, dns_xfrin_ctx_t **target) {
700 	REQUIRE(target != NULL && *target == NULL);
701 	source->refcount++;
702 	*target = source;
703 }
704 
705 void
706 dns_xfrin_detach(dns_xfrin_ctx_t **xfrp) {
707 	dns_xfrin_ctx_t *xfr = *xfrp;
708 	INSIST(xfr->refcount > 0);
709 	xfr->refcount--;
710 	maybe_free(xfr);
711 	*xfrp = NULL;
712 }
713 
714 static void
715 xfrin_cancelio(dns_xfrin_ctx_t *xfr) {
716 	if (xfr->connects > 0) {
717 		isc_socket_cancel(xfr->socket, xfr->task,
718 				  ISC_SOCKCANCEL_CONNECT);
719 	} else if (xfr->recvs > 0) {
720 		dns_tcpmsg_cancelread(&xfr->tcpmsg);
721 	} else if (xfr->sends > 0) {
722 		isc_socket_cancel(xfr->socket, xfr->task,
723 				  ISC_SOCKCANCEL_SEND);
724 	}
725 }
726 
727 static void
728 xfrin_reset(dns_xfrin_ctx_t *xfr) {
729 	REQUIRE(VALID_XFRIN(xfr));
730 
731 	xfrin_log(xfr, ISC_LOG_INFO, "resetting");
732 
733 	xfrin_cancelio(xfr);
734 
735 	if (xfr->socket != NULL)
736 		isc_socket_detach(&xfr->socket);
737 
738 	if (xfr->lasttsig != NULL)
739 		isc_buffer_free(&xfr->lasttsig);
740 
741 	dns_diff_clear(&xfr->diff);
742 	xfr->difflen = 0;
743 
744 	if (xfr->ixfr.journal != NULL)
745 		dns_journal_destroy(&xfr->ixfr.journal);
746 
747 	if (xfr->axfr.add_private != NULL)
748 		(void)dns_db_endload(xfr->db, &xfr->axfr);
749 
750 	if (xfr->tcpmsg_valid) {
751 		dns_tcpmsg_invalidate(&xfr->tcpmsg);
752 		xfr->tcpmsg_valid = false;
753 	}
754 
755 	if (xfr->ver != NULL)
756 		dns_db_closeversion(xfr->db, &xfr->ver, false);
757 }
758 
759 
760 static void
761 xfrin_fail(dns_xfrin_ctx_t *xfr, isc_result_t result, const char *msg) {
762 	if (result != DNS_R_UPTODATE && result != DNS_R_TOOMANYRECORDS) {
763 		xfrin_log(xfr, ISC_LOG_ERROR, "%s: %s",
764 			  msg, isc_result_totext(result));
765 		if (xfr->is_ixfr)
766 			/* Pass special result code to force AXFR retry */
767 			result = DNS_R_BADIXFR;
768 	}
769 	xfrin_cancelio(xfr);
770 	/*
771 	 * Close the journal.
772 	 */
773 	if (xfr->ixfr.journal != NULL)
774 		dns_journal_destroy(&xfr->ixfr.journal);
775 	if (xfr->done != NULL) {
776 		(xfr->done)(xfr->zone, result);
777 		xfr->done = NULL;
778 	}
779 	xfr->shuttingdown = true;
780 	xfr->shutdown_result = result;
781 	maybe_free(xfr);
782 }
783 
784 static isc_result_t
785 xfrin_create(isc_mem_t *mctx,
786 	     dns_zone_t *zone,
787 	     dns_db_t *db,
788 	     isc_task_t *task,
789 	     isc_timermgr_t *timermgr,
790 	     isc_socketmgr_t *socketmgr,
791 	     dns_name_t *zonename,
792 	     dns_rdataclass_t rdclass,
793 	     dns_rdatatype_t reqtype,
794 	     const isc_sockaddr_t *masteraddr,
795 	     const isc_sockaddr_t *sourceaddr,
796 	     isc_dscp_t dscp,
797 	     dns_tsigkey_t *tsigkey,
798 	     dns_xfrin_ctx_t **xfrp)
799 {
800 	dns_xfrin_ctx_t *xfr = NULL;
801 	isc_result_t result;
802 
803 	xfr = isc_mem_get(mctx, sizeof(*xfr));
804 	if (xfr == NULL)
805 		return (ISC_R_NOMEMORY);
806 	xfr->mctx = NULL;
807 	isc_mem_attach(mctx, &xfr->mctx);
808 	xfr->refcount = 0;
809 	xfr->zone = NULL;
810 	dns_zone_iattach(zone, &xfr->zone);
811 	xfr->task = NULL;
812 	isc_task_attach(task, &xfr->task);
813 	xfr->timer = NULL;
814 	xfr->socketmgr = socketmgr;
815 	xfr->done = NULL;
816 
817 	xfr->connects = 0;
818 	xfr->sends = 0;
819 	xfr->recvs = 0;
820 	xfr->shuttingdown = false;
821 	xfr->shutdown_result = ISC_R_UNSET;
822 
823 	dns_name_init(&xfr->name, NULL);
824 	xfr->rdclass = rdclass;
825 	xfr->checkid = true;
826 	xfr->id	= (dns_messageid_t)isc_random16();
827 	xfr->reqtype = reqtype;
828 	xfr->dscp = dscp;
829 
830 	/* sockaddr */
831 	xfr->socket = NULL;
832 	/* qbuffer */
833 	/* qbuffer_data */
834 	/* tcpmsg */
835 	xfr->tcpmsg_valid = false;
836 
837 	xfr->zone_had_db = false;
838 	xfr->db = NULL;
839 	if (db != NULL)
840 		dns_db_attach(db, &xfr->db);
841 	xfr->ver = NULL;
842 	dns_diff_init(xfr->mctx, &xfr->diff);
843 	xfr->difflen = 0;
844 
845 	if (reqtype == dns_rdatatype_soa)
846 		xfr->state = XFRST_SOAQUERY;
847 	else
848 		xfr->state = XFRST_INITIALSOA;
849 	/* end_serial */
850 
851 	xfr->nmsg = 0;
852 	xfr->nrecs = 0;
853 	xfr->nbytes = 0;
854 	xfr->maxrecords = dns_zone_getmaxrecords(zone);
855 	isc_time_now(&xfr->start);
856 
857 	xfr->tsigkey = NULL;
858 	if (tsigkey != NULL)
859 		dns_tsigkey_attach(tsigkey, &xfr->tsigkey);
860 	xfr->lasttsig = NULL;
861 	xfr->tsigctx = NULL;
862 	xfr->sincetsig = 0;
863 	xfr->is_ixfr = false;
864 
865 	/* ixfr.request_serial */
866 	/* ixfr.current_serial */
867 	xfr->ixfr.journal = NULL;
868 
869 	xfr->axfr.add = NULL;
870 	xfr->axfr.add_private = NULL;
871 
872 	CHECK(dns_name_dup(zonename, mctx, &xfr->name));
873 
874 	CHECK(isc_timer_create(timermgr, isc_timertype_inactive, NULL, NULL,
875 			       task, xfrin_timeout, xfr, &xfr->timer));
876 	CHECK(dns_timer_setidle(xfr->timer,
877 				dns_zone_getmaxxfrin(xfr->zone),
878 				dns_zone_getidlein(xfr->zone),
879 				false));
880 
881 	xfr->masteraddr = *masteraddr;
882 
883 	INSIST(isc_sockaddr_pf(masteraddr) == isc_sockaddr_pf(sourceaddr));
884 	xfr->sourceaddr = *sourceaddr;
885 	isc_sockaddr_setport(&xfr->sourceaddr, 0);
886 
887 	/*
888 	 * Reserve 2 bytes for TCP length at the begining of the buffer.
889 	 */
890 	isc_buffer_init(&xfr->qbuffer, &xfr->qbuffer_data[2],
891 			sizeof(xfr->qbuffer_data) - 2);
892 
893 	xfr->magic = XFRIN_MAGIC;
894 	*xfrp = xfr;
895 	return (ISC_R_SUCCESS);
896 
897  failure:
898 	if (xfr->timer != NULL)
899 		isc_timer_detach(&xfr->timer);
900 	if (dns_name_dynamic(&xfr->name))
901 		dns_name_free(&xfr->name, xfr->mctx);
902 	if (xfr->tsigkey != NULL)
903 		dns_tsigkey_detach(&xfr->tsigkey);
904 	if (xfr->db != NULL)
905 		dns_db_detach(&xfr->db);
906 	isc_task_detach(&xfr->task);
907 	dns_zone_idetach(&xfr->zone);
908 	isc_mem_putanddetach(&xfr->mctx, xfr, sizeof(*xfr));
909 
910 	return (result);
911 }
912 
913 static isc_result_t
914 xfrin_start(dns_xfrin_ctx_t *xfr) {
915 	isc_result_t result;
916 	CHECK(isc_socket_create(xfr->socketmgr,
917 				isc_sockaddr_pf(&xfr->sourceaddr),
918 				isc_sockettype_tcp,
919 				&xfr->socket));
920 	isc_socket_setname(xfr->socket, "xfrin", NULL);
921 #ifndef BROKEN_TCP_BIND_BEFORE_CONNECT
922 	CHECK(isc_socket_bind(xfr->socket, &xfr->sourceaddr,
923 			      ISC_SOCKET_REUSEADDRESS));
924 #endif
925 	isc_socket_dscp(xfr->socket, xfr->dscp);
926 	CHECK(isc_socket_connect(xfr->socket, &xfr->masteraddr, xfr->task,
927 				 xfrin_connect_done, xfr));
928 	xfr->connects++;
929 	return (ISC_R_SUCCESS);
930  failure:
931 	xfrin_fail(xfr, result, "failed setting up socket");
932 	return (result);
933 }
934 
935 /* XXX the resolver could use this, too */
936 
937 static isc_result_t
938 render(dns_message_t *msg, isc_mem_t *mctx, isc_buffer_t *buf) {
939 	dns_compress_t cctx;
940 	bool cleanup_cctx = false;
941 	isc_result_t result;
942 
943 	CHECK(dns_compress_init(&cctx, -1, mctx));
944 	cleanup_cctx = true;
945 	CHECK(dns_message_renderbegin(msg, &cctx, buf));
946 	CHECK(dns_message_rendersection(msg, DNS_SECTION_QUESTION, 0));
947 	CHECK(dns_message_rendersection(msg, DNS_SECTION_ANSWER, 0));
948 	CHECK(dns_message_rendersection(msg, DNS_SECTION_AUTHORITY, 0));
949 	CHECK(dns_message_rendersection(msg, DNS_SECTION_ADDITIONAL, 0));
950 	CHECK(dns_message_renderend(msg));
951 	result = ISC_R_SUCCESS;
952  failure:
953 	if (cleanup_cctx)
954 		dns_compress_invalidate(&cctx);
955 	return (result);
956 }
957 
958 /*
959  * A connection has been established.
960  */
961 static void
962 xfrin_connect_done(isc_task_t *task, isc_event_t *event) {
963 	isc_socket_connev_t *cev = (isc_socket_connev_t *) event;
964 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *) event->ev_arg;
965 	isc_result_t result = cev->result;
966 	char sourcetext[ISC_SOCKADDR_FORMATSIZE];
967 	char signerbuf[DNS_NAME_FORMATSIZE];
968 	const char *signer = "", *sep = "";
969 	isc_sockaddr_t sockaddr;
970 	dns_zonemgr_t * zmgr;
971 	isc_time_t now;
972 
973 	REQUIRE(VALID_XFRIN(xfr));
974 
975 	UNUSED(task);
976 
977 	INSIST(event->ev_type == ISC_SOCKEVENT_CONNECT);
978 	isc_event_free(&event);
979 
980 	xfr->connects--;
981 	if (xfr->shuttingdown) {
982 		maybe_free(xfr);
983 		return;
984 	}
985 
986 	zmgr = dns_zone_getmgr(xfr->zone);
987 	if (zmgr != NULL) {
988 		if (result != ISC_R_SUCCESS) {
989 			TIME_NOW(&now);
990 			dns_zonemgr_unreachableadd(zmgr, &xfr->masteraddr,
991 						   &xfr->sourceaddr, &now);
992 			goto failure;
993 		} else
994 			dns_zonemgr_unreachabledel(zmgr, &xfr->masteraddr,
995 						   &xfr->sourceaddr);
996 	}
997 
998 	result = isc_socket_getsockname(xfr->socket, &sockaddr);
999 	if (result == ISC_R_SUCCESS) {
1000 		isc_sockaddr_format(&sockaddr, sourcetext, sizeof(sourcetext));
1001 	} else {
1002 		strlcpy(sourcetext, "<UNKNOWN>", sizeof(sourcetext));
1003 	}
1004 
1005 	if (xfr->tsigkey != NULL && xfr->tsigkey->key != NULL) {
1006 		dns_name_format(dst_key_name(xfr->tsigkey->key),
1007 				signerbuf, sizeof(signerbuf));
1008 		sep = " TSIG ";
1009 		signer = signerbuf;
1010 	}
1011 
1012 	xfrin_log(xfr, ISC_LOG_INFO, "connected using %s%s%s",
1013 		  sourcetext, sep, signer);
1014 
1015 	dns_tcpmsg_init(xfr->mctx, xfr->socket, &xfr->tcpmsg);
1016 	xfr->tcpmsg_valid = true;
1017 
1018 	CHECK(xfrin_send_request(xfr));
1019  failure:
1020 	if (result != ISC_R_SUCCESS)
1021 		xfrin_fail(xfr, result, "failed to connect");
1022 }
1023 
1024 /*
1025  * Convert a tuple into a dns_name_t suitable for inserting
1026  * into the given dns_message_t.
1027  */
1028 static isc_result_t
1029 tuple2msgname(dns_difftuple_t *tuple, dns_message_t *msg, dns_name_t **target)
1030 {
1031 	isc_result_t result;
1032 	dns_rdata_t *rdata = NULL;
1033 	dns_rdatalist_t *rdl = NULL;
1034 	dns_rdataset_t *rds = NULL;
1035 	dns_name_t *name = NULL;
1036 
1037 	REQUIRE(target != NULL && *target == NULL);
1038 
1039 	CHECK(dns_message_gettemprdata(msg, &rdata));
1040 	dns_rdata_init(rdata);
1041 	dns_rdata_clone(&tuple->rdata, rdata);
1042 
1043 	CHECK(dns_message_gettemprdatalist(msg, &rdl));
1044 	dns_rdatalist_init(rdl);
1045 	rdl->type = tuple->rdata.type;
1046 	rdl->rdclass = tuple->rdata.rdclass;
1047 	rdl->ttl = tuple->ttl;
1048 	ISC_LIST_APPEND(rdl->rdata, rdata, link);
1049 
1050 	CHECK(dns_message_gettemprdataset(msg, &rds));
1051 	CHECK(dns_rdatalist_tordataset(rdl, rds));
1052 
1053 	CHECK(dns_message_gettempname(msg, &name));
1054 	dns_name_init(name, NULL);
1055 	dns_name_clone(&tuple->name, name);
1056 	ISC_LIST_APPEND(name->list, rds, link);
1057 
1058 	*target = name;
1059 	return (ISC_R_SUCCESS);
1060 
1061  failure:
1062 
1063 	if (rds != NULL) {
1064 		dns_rdataset_disassociate(rds);
1065 		dns_message_puttemprdataset(msg, &rds);
1066 	}
1067 	if (rdl != NULL) {
1068 		ISC_LIST_UNLINK(rdl->rdata, rdata, link);
1069 		dns_message_puttemprdatalist(msg, &rdl);
1070 	}
1071 	if (rdata != NULL)
1072 		dns_message_puttemprdata(msg, &rdata);
1073 
1074 	return (result);
1075 }
1076 
1077 
1078 /*
1079  * Build an *XFR request and send its length prefix.
1080  */
1081 static isc_result_t
1082 xfrin_send_request(dns_xfrin_ctx_t *xfr) {
1083 	isc_result_t result;
1084 	isc_region_t region;
1085 	dns_rdataset_t *qrdataset = NULL;
1086 	dns_message_t *msg = NULL;
1087 	dns_difftuple_t *soatuple = NULL;
1088 	dns_name_t *qname = NULL;
1089 	dns_dbversion_t *ver = NULL;
1090 	dns_name_t *msgsoaname = NULL;
1091 
1092 	/* Create the request message */
1093 	CHECK(dns_message_create(xfr->mctx, DNS_MESSAGE_INTENTRENDER, &msg));
1094 	CHECK(dns_message_settsigkey(msg, xfr->tsigkey));
1095 
1096 	/* Create a name for the question section. */
1097 	CHECK(dns_message_gettempname(msg, &qname));
1098 	dns_name_init(qname, NULL);
1099 	dns_name_clone(&xfr->name, qname);
1100 
1101 	/* Formulate the question and attach it to the question name. */
1102 	CHECK(dns_message_gettemprdataset(msg, &qrdataset));
1103 	dns_rdataset_makequestion(qrdataset, xfr->rdclass, xfr->reqtype);
1104 	ISC_LIST_APPEND(qname->list, qrdataset, link);
1105 	qrdataset = NULL;
1106 
1107 	dns_message_addname(msg, qname, DNS_SECTION_QUESTION);
1108 	qname = NULL;
1109 
1110 	if (xfr->reqtype == dns_rdatatype_ixfr) {
1111 		/* Get the SOA and add it to the authority section. */
1112 		/* XXX is using the current version the right thing? */
1113 		dns_db_currentversion(xfr->db, &ver);
1114 		CHECK(dns_db_createsoatuple(xfr->db, ver, xfr->mctx,
1115 					    DNS_DIFFOP_EXISTS, &soatuple));
1116 		xfr->ixfr.request_serial = dns_soa_getserial(&soatuple->rdata);
1117 		xfr->ixfr.current_serial = xfr->ixfr.request_serial;
1118 		xfrin_log(xfr, ISC_LOG_DEBUG(3),
1119 			  "requesting IXFR for serial %u",
1120 			  xfr->ixfr.request_serial);
1121 
1122 		CHECK(tuple2msgname(soatuple, msg, &msgsoaname));
1123 		dns_message_addname(msg, msgsoaname, DNS_SECTION_AUTHORITY);
1124 	} else if (xfr->reqtype == dns_rdatatype_soa)
1125 		CHECK(dns_db_getsoaserial(xfr->db, NULL,
1126 					  &xfr->ixfr.request_serial));
1127 
1128 	xfr->checkid = true;
1129 	xfr->id++;
1130 	xfr->nmsg = 0;
1131 	xfr->nrecs = 0;
1132 	xfr->nbytes = 0;
1133 	isc_time_now(&xfr->start);
1134 	msg->id = xfr->id;
1135 	if (xfr->tsigctx != NULL)
1136 		dst_context_destroy(&xfr->tsigctx);
1137 
1138 	CHECK(render(msg, xfr->mctx, &xfr->qbuffer));
1139 
1140 	/*
1141 	 * Free the last tsig, if there is one.
1142 	 */
1143 	if (xfr->lasttsig != NULL)
1144 		isc_buffer_free(&xfr->lasttsig);
1145 
1146 	/*
1147 	 * Save the query TSIG and don't let message_destroy free it.
1148 	 */
1149 	CHECK(dns_message_getquerytsig(msg, xfr->mctx, &xfr->lasttsig));
1150 
1151 	isc_buffer_usedregion(&xfr->qbuffer, &region);
1152 	INSIST(region.length <= 65535);
1153 
1154 	/*
1155 	 * Record message length and adjust region to include TCP
1156 	 * length field.
1157 	 */
1158 	xfr->qbuffer_data[0] = (region.length >> 8) & 0xff;
1159 	xfr->qbuffer_data[1] = region.length & 0xff;
1160 	region.base -= 2;
1161 	region.length += 2;
1162 	CHECK(isc_socket_send(xfr->socket, &region, xfr->task,
1163 			      xfrin_send_done, xfr));
1164 	xfr->sends++;
1165 
1166  failure:
1167 	if (qname != NULL)
1168 		dns_message_puttempname(msg, &qname);
1169 	if (qrdataset != NULL)
1170 		dns_message_puttemprdataset(msg, &qrdataset);
1171 	if (msg != NULL)
1172 		dns_message_destroy(&msg);
1173 	if (soatuple != NULL)
1174 		dns_difftuple_free(&soatuple);
1175 	if (ver != NULL)
1176 		dns_db_closeversion(xfr->db, &ver, false);
1177 	return (result);
1178 }
1179 
1180 static void
1181 xfrin_send_done(isc_task_t *task, isc_event_t *event) {
1182 	isc_socketevent_t *sev = (isc_socketevent_t *) event;
1183 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *) event->ev_arg;
1184 	isc_result_t result;
1185 
1186 	REQUIRE(VALID_XFRIN(xfr));
1187 
1188 	UNUSED(task);
1189 
1190 	INSIST(event->ev_type == ISC_SOCKEVENT_SENDDONE);
1191 
1192 	xfr->sends--;
1193 	xfrin_log(xfr, ISC_LOG_DEBUG(3), "sent request data");
1194 	CHECK(sev->result);
1195 
1196 	CHECK(dns_tcpmsg_readmessage(&xfr->tcpmsg, xfr->task,
1197 				     xfrin_recv_done, xfr));
1198 	xfr->recvs++;
1199  failure:
1200 	isc_event_free(&event);
1201 	if (result != ISC_R_SUCCESS)
1202 		xfrin_fail(xfr, result, "failed sending request data");
1203 }
1204 
1205 
1206 static void
1207 xfrin_recv_done(isc_task_t *task, isc_event_t *ev) {
1208 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *) ev->ev_arg;
1209 	isc_result_t result;
1210 	dns_message_t *msg = NULL;
1211 	dns_name_t *name;
1212 	dns_tcpmsg_t *tcpmsg;
1213 	const dns_name_t *tsigowner = NULL;
1214 
1215 	REQUIRE(VALID_XFRIN(xfr));
1216 
1217 	UNUSED(task);
1218 
1219 	INSIST(ev->ev_type == DNS_EVENT_TCPMSG);
1220 	tcpmsg = ev->ev_sender;
1221 	isc_event_free(&ev);
1222 
1223 	xfr->recvs--;
1224 	if (xfr->shuttingdown) {
1225 		maybe_free(xfr);
1226 		return;
1227 	}
1228 
1229 	CHECK(tcpmsg->result);
1230 
1231 	xfrin_log(xfr, ISC_LOG_DEBUG(7), "received %u bytes",
1232 		  tcpmsg->buffer.used);
1233 
1234 	CHECK(isc_timer_touch(xfr->timer));
1235 
1236 	CHECK(dns_message_create(xfr->mctx, DNS_MESSAGE_INTENTPARSE, &msg));
1237 
1238 	CHECK(dns_message_settsigkey(msg, xfr->tsigkey));
1239 	CHECK(dns_message_setquerytsig(msg, xfr->lasttsig));
1240 
1241 	msg->tsigctx = xfr->tsigctx;
1242 	xfr->tsigctx = NULL;
1243 
1244 	dns_message_setclass(msg, xfr->rdclass);
1245 
1246 	if (xfr->nmsg > 0)
1247 		msg->tcp_continuation = 1;
1248 
1249 	result = dns_message_parse(msg, &tcpmsg->buffer,
1250 				   DNS_MESSAGEPARSE_PRESERVEORDER);
1251 
1252 	if (result == ISC_R_SUCCESS)
1253 		dns_message_logpacket(msg, "received message from",
1254 				      &tcpmsg->address,
1255 				      DNS_LOGCATEGORY_XFER_IN,
1256 				      DNS_LOGMODULE_XFER_IN,
1257 				      ISC_LOG_DEBUG(10), xfr->mctx);
1258 	else
1259 		xfrin_log(xfr, ISC_LOG_DEBUG(10), "dns_message_parse: %s",
1260 			  dns_result_totext(result));
1261 
1262 	if (result != ISC_R_SUCCESS || msg->rcode != dns_rcode_noerror ||
1263 	    msg->opcode != dns_opcode_query ||msg->rdclass != xfr->rdclass ||
1264 	    (xfr->checkid && msg->id != xfr->id)) {
1265 		if (result == ISC_R_SUCCESS && msg->rcode != dns_rcode_noerror)
1266 			result = ISC_RESULTCLASS_DNSRCODE + msg->rcode; /*XXX*/
1267 		else if (result == ISC_R_SUCCESS &&
1268 			 msg->opcode != dns_opcode_query)
1269 			result = DNS_R_UNEXPECTEDOPCODE;
1270 		else if (result == ISC_R_SUCCESS &&
1271 			 msg->rdclass != xfr->rdclass)
1272 			result = DNS_R_BADCLASS;
1273 		else if (result == ISC_R_SUCCESS || result == DNS_R_NOERROR)
1274 			result = DNS_R_UNEXPECTEDID;
1275 		if (xfr->reqtype == dns_rdatatype_axfr ||
1276 		    xfr->reqtype == dns_rdatatype_soa)
1277 			goto failure;
1278 		xfrin_log(xfr, ISC_LOG_DEBUG(3), "got %s, retrying with AXFR",
1279 		       isc_result_totext(result));
1280  try_axfr:
1281 		dns_message_destroy(&msg);
1282 		xfrin_reset(xfr);
1283 		xfr->reqtype = dns_rdatatype_soa;
1284 		xfr->state = XFRST_SOAQUERY;
1285 		(void)xfrin_start(xfr);
1286 		return;
1287 	}
1288 
1289 	/*
1290 	 * Does the server know about IXFR?  If it doesn't we will get
1291 	 * a message with a empty answer section or a potentially a CNAME /
1292 	 * DNAME, the later is handled by xfr_rr() which will return FORMERR
1293 	 * if the first RR in the answer section is not a SOA record.
1294 	 */
1295 	if (xfr->reqtype == dns_rdatatype_ixfr &&
1296 	    xfr->state == XFRST_INITIALSOA &&
1297 	    msg->counts[DNS_SECTION_ANSWER] == 0) {
1298 		xfrin_log(xfr, ISC_LOG_DEBUG(3),
1299 			  "empty answer section, retrying with AXFR");
1300 		goto try_axfr;
1301 	}
1302 
1303 	if (xfr->reqtype == dns_rdatatype_soa &&
1304 	    (msg->flags & DNS_MESSAGEFLAG_AA) == 0) {
1305 		FAIL(DNS_R_NOTAUTHORITATIVE);
1306 	}
1307 
1308 
1309 	result = dns_message_checksig(msg, dns_zone_getview(xfr->zone));
1310 	if (result != ISC_R_SUCCESS) {
1311 		xfrin_log(xfr, ISC_LOG_DEBUG(3), "TSIG check failed: %s",
1312 		       isc_result_totext(result));
1313 		goto failure;
1314 	}
1315 
1316 	for (result = dns_message_firstname(msg, DNS_SECTION_ANSWER);
1317 	     result == ISC_R_SUCCESS;
1318 	     result = dns_message_nextname(msg, DNS_SECTION_ANSWER))
1319 	{
1320 		dns_rdataset_t *rds;
1321 
1322 		name = NULL;
1323 		dns_message_currentname(msg, DNS_SECTION_ANSWER, &name);
1324 		for (rds = ISC_LIST_HEAD(name->list);
1325 		     rds != NULL;
1326 		     rds = ISC_LIST_NEXT(rds, link))
1327 		{
1328 			for (result = dns_rdataset_first(rds);
1329 			     result == ISC_R_SUCCESS;
1330 			     result = dns_rdataset_next(rds))
1331 			{
1332 				dns_rdata_t rdata = DNS_RDATA_INIT;
1333 				dns_rdataset_current(rds, &rdata);
1334 				CHECK(xfr_rr(xfr, name, rds->ttl, &rdata));
1335 			}
1336 		}
1337 	}
1338 	if (result != ISC_R_NOMORE)
1339 		goto failure;
1340 
1341 	if (dns_message_gettsig(msg, &tsigowner) != NULL) {
1342 		/*
1343 		 * Reset the counter.
1344 		 */
1345 		xfr->sincetsig = 0;
1346 
1347 		/*
1348 		 * Free the last tsig, if there is one.
1349 		 */
1350 		if (xfr->lasttsig != NULL)
1351 			isc_buffer_free(&xfr->lasttsig);
1352 
1353 		/*
1354 		 * Update the last tsig pointer.
1355 		 */
1356 		CHECK(dns_message_getquerytsig(msg, xfr->mctx,
1357 					       &xfr->lasttsig));
1358 
1359 	} else if (dns_message_gettsigkey(msg) != NULL) {
1360 		xfr->sincetsig++;
1361 		if (xfr->sincetsig > 100 || xfr->nmsg == 0 ||
1362 		    xfr->state == XFRST_AXFR_END ||
1363 		    xfr->state == XFRST_IXFR_END)
1364 		{
1365 			result = DNS_R_EXPECTEDTSIG;
1366 			goto failure;
1367 		}
1368 	}
1369 
1370 	/*
1371 	 * Update the number of messages received.
1372 	 */
1373 	xfr->nmsg++;
1374 
1375 	/*
1376 	 * Update the number of bytes received.
1377 	 */
1378 	xfr->nbytes += tcpmsg->buffer.used;
1379 
1380 	/*
1381 	 * Take the context back.
1382 	 */
1383 	INSIST(xfr->tsigctx == NULL);
1384 	xfr->tsigctx = msg->tsigctx;
1385 	msg->tsigctx = NULL;
1386 
1387 	dns_message_destroy(&msg);
1388 
1389 	switch (xfr->state) {
1390 	case XFRST_GOTSOA:
1391 		xfr->reqtype = dns_rdatatype_axfr;
1392 		xfr->state = XFRST_INITIALSOA;
1393 		CHECK(xfrin_send_request(xfr));
1394 		break;
1395 	case XFRST_AXFR_END:
1396 		CHECK(axfr_finalize(xfr));
1397 		/* FALLTHROUGH */
1398 	case XFRST_IXFR_END:
1399 		/*
1400 		 * Close the journal.
1401 		 */
1402 		if (xfr->ixfr.journal != NULL)
1403 			dns_journal_destroy(&xfr->ixfr.journal);
1404 
1405 		/*
1406 		 * Inform the caller we succeeded.
1407 		 */
1408 		if (xfr->done != NULL) {
1409 			(xfr->done)(xfr->zone, ISC_R_SUCCESS);
1410 			xfr->done = NULL;
1411 		}
1412 		/*
1413 		 * We should have no outstanding events at this
1414 		 * point, thus maybe_free() should succeed.
1415 		 */
1416 		xfr->shuttingdown = true;
1417 		xfr->shutdown_result = ISC_R_SUCCESS;
1418 		maybe_free(xfr);
1419 		break;
1420 	default:
1421 		/*
1422 		 * Read the next message.
1423 		 */
1424 		CHECK(dns_tcpmsg_readmessage(&xfr->tcpmsg, xfr->task,
1425 					     xfrin_recv_done, xfr));
1426 		xfr->recvs++;
1427 	}
1428 	return;
1429 
1430  failure:
1431 	if (msg != NULL)
1432 		dns_message_destroy(&msg);
1433 	if (result != ISC_R_SUCCESS)
1434 		xfrin_fail(xfr, result, "failed while receiving responses");
1435 }
1436 
1437 static void
1438 xfrin_timeout(isc_task_t *task, isc_event_t *event) {
1439 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *) event->ev_arg;
1440 
1441 	REQUIRE(VALID_XFRIN(xfr));
1442 
1443 	UNUSED(task);
1444 
1445 	isc_event_free(&event);
1446 	/*
1447 	 * This will log "giving up: timeout".
1448 	 */
1449 	xfrin_fail(xfr, ISC_R_TIMEDOUT, "giving up");
1450 }
1451 
1452 static void
1453 maybe_free(dns_xfrin_ctx_t *xfr) {
1454 	uint64_t msecs;
1455 	uint64_t persec;
1456 	const char *result_str;
1457 
1458 	REQUIRE(VALID_XFRIN(xfr));
1459 
1460 	if (! xfr->shuttingdown || xfr->refcount != 0 ||
1461 	    xfr->connects != 0 || xfr->sends != 0 ||
1462 	    xfr->recvs != 0)
1463 		return;
1464 
1465 	INSIST(! xfr->shuttingdown || xfr->shutdown_result != ISC_R_UNSET);
1466 
1467 	/* If we're called through dns_xfrin_detach() and are not
1468 	 * shutting down, we can't know what the transfer status is as
1469 	 * we are only called when the last reference is lost.
1470 	 */
1471 	result_str = (xfr->shuttingdown ?
1472 		      isc_result_totext(xfr->shutdown_result) : "unknown");
1473 	xfrin_log(xfr, ISC_LOG_INFO, "Transfer status: %s", result_str);
1474 
1475 	/*
1476 	 * Calculate the length of time the transfer took,
1477 	 * and print a log message with the bytes and rate.
1478 	 */
1479 	isc_time_now(&xfr->end);
1480 	msecs = isc_time_microdiff(&xfr->end, &xfr->start) / 1000;
1481 	if (msecs == 0)
1482 		msecs = 1;
1483 	persec = (xfr->nbytes * 1000) / msecs;
1484 	xfrin_log(xfr, ISC_LOG_INFO,
1485 		  "Transfer completed: %d messages, %d records, "
1486 		  "%" PRIu64 " bytes, "
1487 		  "%u.%03u secs (%u bytes/sec)",
1488 		  xfr->nmsg, xfr->nrecs, xfr->nbytes,
1489 		  (unsigned int) (msecs / 1000), (unsigned int) (msecs % 1000),
1490 		  (unsigned int) persec);
1491 
1492 	if (xfr->socket != NULL)
1493 		isc_socket_detach(&xfr->socket);
1494 
1495 	if (xfr->timer != NULL)
1496 		isc_timer_detach(&xfr->timer);
1497 
1498 	if (xfr->task != NULL)
1499 		isc_task_detach(&xfr->task);
1500 
1501 	if (xfr->tsigkey != NULL)
1502 		dns_tsigkey_detach(&xfr->tsigkey);
1503 
1504 	if (xfr->lasttsig != NULL)
1505 		isc_buffer_free(&xfr->lasttsig);
1506 
1507 	dns_diff_clear(&xfr->diff);
1508 
1509 	if (xfr->ixfr.journal != NULL)
1510 		dns_journal_destroy(&xfr->ixfr.journal);
1511 
1512 	if (xfr->axfr.add_private != NULL)
1513 		(void)dns_db_endload(xfr->db, &xfr->axfr);
1514 
1515 	if (xfr->tcpmsg_valid)
1516 		dns_tcpmsg_invalidate(&xfr->tcpmsg);
1517 
1518 	if (xfr->tsigctx != NULL)
1519 		dst_context_destroy(&xfr->tsigctx);
1520 
1521 	if ((xfr->name.attributes & DNS_NAMEATTR_DYNAMIC) != 0)
1522 		dns_name_free(&xfr->name, xfr->mctx);
1523 
1524 	if (xfr->ver != NULL)
1525 		dns_db_closeversion(xfr->db, &xfr->ver, false);
1526 
1527 	if (xfr->db != NULL)
1528 		dns_db_detach(&xfr->db);
1529 
1530 	if (xfr->zone != NULL) {
1531 		if (!xfr->zone_had_db &&
1532 		    xfr->shuttingdown &&
1533 		    xfr->shutdown_result == ISC_R_SUCCESS &&
1534 		    dns_zone_gettype(xfr->zone) == dns_zone_mirror)
1535 		{
1536 			dns_zone_log(xfr->zone, ISC_LOG_INFO,
1537 				     "mirror zone is now in use");
1538 		}
1539 		xfrin_log(xfr, ISC_LOG_DEBUG(99), "freeing transfer context");
1540 		/*
1541 		 * xfr->zone must not be detached before xfrin_log() is called.
1542 		 */
1543 		dns_zone_idetach(&xfr->zone);
1544 	}
1545 
1546 	isc_mem_putanddetach(&xfr->mctx, xfr, sizeof(*xfr));
1547 }
1548 
1549 /*
1550  * Log incoming zone transfer messages in a format like
1551  * transfer of <zone> from <address>: <message>
1552  */
1553 static void
1554 xfrin_logv(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
1555 	   const char *fmt, va_list ap)
1556 {
1557 	char mastertext[ISC_SOCKADDR_FORMATSIZE];
1558 	char msgtext[2048];
1559 
1560 	isc_sockaddr_format(masteraddr, mastertext, sizeof(mastertext));
1561 	vsnprintf(msgtext, sizeof(msgtext), fmt, ap);
1562 
1563 	isc_log_write(dns_lctx, DNS_LOGCATEGORY_XFER_IN,
1564 		      DNS_LOGMODULE_XFER_IN, level,
1565 		      "transfer of '%s' from %s: %s",
1566 		      zonetext, mastertext, msgtext);
1567 }
1568 
1569 /*
1570  * Logging function for use when a xfrin_ctx_t has not yet been created.
1571  */
1572 
1573 static void
1574 xfrin_log1(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
1575 	   const char *fmt, ...)
1576 {
1577 	va_list ap;
1578 
1579 	if (isc_log_wouldlog(dns_lctx, level) == false)
1580 		return;
1581 
1582 	va_start(ap, fmt);
1583 	xfrin_logv(level, zonetext, masteraddr, fmt, ap);
1584 	va_end(ap);
1585 }
1586 
1587 /*
1588  * Logging function for use when there is a xfrin_ctx_t.
1589  */
1590 
1591 static void
1592 xfrin_log(dns_xfrin_ctx_t *xfr, int level, const char *fmt, ...)
1593 {
1594 	va_list ap;
1595 	char zonetext[DNS_NAME_MAXTEXT+32];
1596 
1597 	if (isc_log_wouldlog(dns_lctx, level) == false)
1598 		return;
1599 
1600 	dns_zone_name(xfr->zone, zonetext, sizeof(zonetext));
1601 
1602 	va_start(ap, fmt);
1603 	xfrin_logv(level, zonetext, &xfr->masteraddr, fmt, ap);
1604 	va_end(ap);
1605 }
1606