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xfrin.c revision 1.1.1.8
      1 /*	$NetBSD: xfrin.c,v 1.1.1.8 2021/08/19 11:45:25 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 https://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 /*! \file */
     15 
     16 #include <inttypes.h>
     17 #include <stdbool.h>
     18 
     19 #include <isc/mem.h>
     20 #include <isc/print.h>
     21 #include <isc/random.h>
     22 #include <isc/string.h> /* Required for HP/UX (and others?) */
     23 #include <isc/task.h>
     24 #include <isc/timer.h>
     25 #include <isc/util.h>
     26 
     27 #include <dns/callbacks.h>
     28 #include <dns/catz.h>
     29 #include <dns/db.h>
     30 #include <dns/diff.h>
     31 #include <dns/events.h>
     32 #include <dns/journal.h>
     33 #include <dns/log.h>
     34 #include <dns/message.h>
     35 #include <dns/rdataclass.h>
     36 #include <dns/rdatalist.h>
     37 #include <dns/rdataset.h>
     38 #include <dns/result.h>
     39 #include <dns/soa.h>
     40 #include <dns/tcpmsg.h>
     41 #include <dns/timer.h>
     42 #include <dns/tsig.h>
     43 #include <dns/view.h>
     44 #include <dns/xfrin.h>
     45 #include <dns/zone.h>
     46 
     47 #include <dst/dst.h>
     48 
     49 /*
     50  * Incoming AXFR and IXFR.
     51  */
     52 
     53 /*%
     54  * It would be non-sensical (or at least obtuse) to use FAIL() with an
     55  * ISC_R_SUCCESS code, but the test is there to keep the Solaris compiler
     56  * from complaining about "end-of-loop code not reached".
     57  */
     58 #define FAIL(code)                           \
     59 	do {                                 \
     60 		result = (code);             \
     61 		if (result != ISC_R_SUCCESS) \
     62 			goto failure;        \
     63 	} while (0)
     64 
     65 #define CHECK(op)                            \
     66 	do {                                 \
     67 		result = (op);               \
     68 		if (result != ISC_R_SUCCESS) \
     69 			goto failure;        \
     70 	} while (0)
     71 
     72 /*%
     73  * The states of the *XFR state machine.  We handle both IXFR and AXFR
     74  * with a single integrated state machine because they cannot be distinguished
     75  * immediately - an AXFR response to an IXFR request can only be detected
     76  * when the first two (2) response RRs have already been received.
     77  */
     78 typedef enum {
     79 	XFRST_SOAQUERY,
     80 	XFRST_GOTSOA,
     81 	XFRST_INITIALSOA,
     82 	XFRST_FIRSTDATA,
     83 	XFRST_IXFR_DELSOA,
     84 	XFRST_IXFR_DEL,
     85 	XFRST_IXFR_ADDSOA,
     86 	XFRST_IXFR_ADD,
     87 	XFRST_IXFR_END,
     88 	XFRST_AXFR,
     89 	XFRST_AXFR_END
     90 } xfrin_state_t;
     91 
     92 /*%
     93  * Incoming zone transfer context.
     94  */
     95 
     96 struct dns_xfrin_ctx {
     97 	unsigned int magic;
     98 	isc_mem_t *mctx;
     99 	dns_zone_t *zone;
    100 
    101 	int refcount;
    102 
    103 	isc_task_t *task;
    104 	isc_timer_t *timer;
    105 	isc_socketmgr_t *socketmgr;
    106 
    107 	int connects; /*%< Connect in progress */
    108 	int sends;    /*%< Send in progress */
    109 	int recvs;    /*%< Receive in progress */
    110 	bool shuttingdown;
    111 	isc_result_t shutdown_result;
    112 
    113 	dns_name_t name; /*%< Name of zone to transfer */
    114 	dns_rdataclass_t rdclass;
    115 
    116 	bool checkid, logit;
    117 	dns_messageid_t id;
    118 
    119 	/*%
    120 	 * Requested transfer type (dns_rdatatype_axfr or
    121 	 * dns_rdatatype_ixfr).  The actual transfer type
    122 	 * may differ due to IXFR->AXFR fallback.
    123 	 */
    124 	dns_rdatatype_t reqtype;
    125 	isc_dscp_t dscp;
    126 
    127 	isc_sockaddr_t masteraddr;
    128 	isc_sockaddr_t sourceaddr;
    129 	isc_socket_t *socket;
    130 
    131 	/*% Buffer for IXFR/AXFR request message */
    132 	isc_buffer_t qbuffer;
    133 	unsigned char qbuffer_data[512];
    134 
    135 	/*% Incoming reply TCP message */
    136 	dns_tcpmsg_t tcpmsg;
    137 	bool tcpmsg_valid;
    138 
    139 	/*%
    140 	 * Whether the zone originally had a database attached at the time this
    141 	 * transfer context was created.  Used by maybe_free() when making
    142 	 * logging decisions.
    143 	 */
    144 	bool zone_had_db;
    145 
    146 	dns_db_t *db;
    147 	dns_dbversion_t *ver;
    148 	dns_diff_t diff; /*%< Pending database changes */
    149 	int difflen;	 /*%< Number of pending tuples */
    150 
    151 	xfrin_state_t state;
    152 	uint32_t end_serial;
    153 	bool is_ixfr;
    154 
    155 	unsigned int nmsg;  /*%< Number of messages recvd */
    156 	unsigned int nrecs; /*%< Number of records recvd */
    157 	uint64_t nbytes;    /*%< Number of bytes received */
    158 
    159 	unsigned int maxrecords; /*%< The maximum number of
    160 				  *   records set for the zone */
    161 
    162 	isc_time_t start; /*%< Start time of the transfer */
    163 	isc_time_t end;	  /*%< End time of the transfer */
    164 
    165 	dns_tsigkey_t *tsigkey; /*%< Key used to create TSIG */
    166 	isc_buffer_t *lasttsig; /*%< The last TSIG */
    167 	dst_context_t *tsigctx; /*%< TSIG verification context */
    168 	unsigned int sincetsig; /*%< recvd since the last TSIG */
    169 	dns_xfrindone_t done;
    170 
    171 	/*%
    172 	 * AXFR- and IXFR-specific data.  Only one is used at a time
    173 	 * according to the is_ixfr flag, so this could be a union,
    174 	 * but keeping them separate makes it a bit simpler to clean
    175 	 * things up when destroying the context.
    176 	 */
    177 	dns_rdatacallbacks_t axfr;
    178 
    179 	struct {
    180 		uint32_t request_serial;
    181 		uint32_t current_serial;
    182 		dns_journal_t *journal;
    183 	} ixfr;
    184 
    185 	dns_rdata_t firstsoa;
    186 	unsigned char *firstsoa_data;
    187 };
    188 
    189 #define XFRIN_MAGIC    ISC_MAGIC('X', 'f', 'r', 'I')
    190 #define VALID_XFRIN(x) ISC_MAGIC_VALID(x, XFRIN_MAGIC)
    191 
    192 /**************************************************************************/
    193 /*
    194  * Forward declarations.
    195  */
    196 
    197 static isc_result_t
    198 xfrin_create(isc_mem_t *mctx, dns_zone_t *zone, dns_db_t *db, isc_task_t *task,
    199 	     isc_timermgr_t *timermgr, isc_socketmgr_t *socketmgr,
    200 	     dns_name_t *zonename, dns_rdataclass_t rdclass,
    201 	     dns_rdatatype_t reqtype, const isc_sockaddr_t *masteraddr,
    202 	     const isc_sockaddr_t *sourceaddr, isc_dscp_t dscp,
    203 	     dns_tsigkey_t *tsigkey, dns_xfrin_ctx_t **xfrp);
    204 
    205 static isc_result_t
    206 axfr_init(dns_xfrin_ctx_t *xfr);
    207 static isc_result_t
    208 axfr_makedb(dns_xfrin_ctx_t *xfr, dns_db_t **dbp);
    209 static isc_result_t
    210 axfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op, dns_name_t *name,
    211 	     dns_ttl_t ttl, dns_rdata_t *rdata);
    212 static isc_result_t
    213 axfr_apply(dns_xfrin_ctx_t *xfr);
    214 static isc_result_t
    215 axfr_commit(dns_xfrin_ctx_t *xfr);
    216 static isc_result_t
    217 axfr_finalize(dns_xfrin_ctx_t *xfr);
    218 
    219 static isc_result_t
    220 ixfr_init(dns_xfrin_ctx_t *xfr);
    221 static isc_result_t
    222 ixfr_apply(dns_xfrin_ctx_t *xfr);
    223 static isc_result_t
    224 ixfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op, dns_name_t *name,
    225 	     dns_ttl_t ttl, dns_rdata_t *rdata);
    226 static isc_result_t
    227 ixfr_commit(dns_xfrin_ctx_t *xfr);
    228 
    229 static isc_result_t
    230 xfr_rr(dns_xfrin_ctx_t *xfr, dns_name_t *name, uint32_t ttl,
    231        dns_rdata_t *rdata);
    232 
    233 static isc_result_t
    234 xfrin_start(dns_xfrin_ctx_t *xfr);
    235 
    236 static void
    237 xfrin_connect_done(isc_task_t *task, isc_event_t *event);
    238 static isc_result_t
    239 xfrin_send_request(dns_xfrin_ctx_t *xfr);
    240 static void
    241 xfrin_send_done(isc_task_t *task, isc_event_t *event);
    242 static void
    243 xfrin_recv_done(isc_task_t *task, isc_event_t *event);
    244 static void
    245 xfrin_timeout(isc_task_t *task, isc_event_t *event);
    246 
    247 static void
    248 maybe_free(dns_xfrin_ctx_t *xfr);
    249 
    250 static void
    251 xfrin_fail(dns_xfrin_ctx_t *xfr, isc_result_t result, const char *msg);
    252 static isc_result_t
    253 render(dns_message_t *msg, isc_mem_t *mctx, isc_buffer_t *buf);
    254 
    255 static void
    256 xfrin_logv(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
    257 	   const char *fmt, va_list ap) ISC_FORMAT_PRINTF(4, 0);
    258 
    259 static void
    260 xfrin_log1(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
    261 	   const char *fmt, ...) ISC_FORMAT_PRINTF(4, 5);
    262 
    263 static void
    264 xfrin_log(dns_xfrin_ctx_t *xfr, int level, const char *fmt, ...)
    265 	ISC_FORMAT_PRINTF(3, 4);
    266 
    267 /**************************************************************************/
    268 /*
    269  * AXFR handling
    270  */
    271 
    272 static isc_result_t
    273 axfr_init(dns_xfrin_ctx_t *xfr) {
    274 	isc_result_t result;
    275 
    276 	xfr->is_ixfr = false;
    277 
    278 	if (xfr->db != NULL) {
    279 		dns_db_detach(&xfr->db);
    280 	}
    281 
    282 	CHECK(axfr_makedb(xfr, &xfr->db));
    283 	dns_rdatacallbacks_init(&xfr->axfr);
    284 	CHECK(dns_db_beginload(xfr->db, &xfr->axfr));
    285 	result = ISC_R_SUCCESS;
    286 failure:
    287 	return (result);
    288 }
    289 
    290 static isc_result_t
    291 axfr_makedb(dns_xfrin_ctx_t *xfr, dns_db_t **dbp) {
    292 	isc_result_t result;
    293 
    294 	result = dns_db_create(xfr->mctx, /* XXX */
    295 			       "rbt",	  /* XXX guess */
    296 			       &xfr->name, dns_dbtype_zone, xfr->rdclass, 0,
    297 			       NULL, /* XXX guess */
    298 			       dbp);
    299 	if (result == ISC_R_SUCCESS) {
    300 		dns_zone_rpz_enable_db(xfr->zone, *dbp);
    301 		dns_zone_catz_enable_db(xfr->zone, *dbp);
    302 	}
    303 	return (result);
    304 }
    305 
    306 static isc_result_t
    307 axfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op, dns_name_t *name,
    308 	     dns_ttl_t ttl, dns_rdata_t *rdata) {
    309 	isc_result_t result;
    310 
    311 	dns_difftuple_t *tuple = NULL;
    312 
    313 	if (rdata->rdclass != xfr->rdclass) {
    314 		return (DNS_R_BADCLASS);
    315 	}
    316 
    317 	CHECK(dns_zone_checknames(xfr->zone, name, rdata));
    318 	CHECK(dns_difftuple_create(xfr->diff.mctx, op, name, ttl, rdata,
    319 				   &tuple));
    320 	dns_diff_append(&xfr->diff, &tuple);
    321 	if (++xfr->difflen > 100) {
    322 		CHECK(axfr_apply(xfr));
    323 	}
    324 	result = ISC_R_SUCCESS;
    325 failure:
    326 	return (result);
    327 }
    328 
    329 /*
    330  * Store a set of AXFR RRs in the database.
    331  */
    332 static isc_result_t
    333 axfr_apply(dns_xfrin_ctx_t *xfr) {
    334 	isc_result_t result;
    335 	uint64_t records;
    336 
    337 	CHECK(dns_diff_load(&xfr->diff, xfr->axfr.add, xfr->axfr.add_private));
    338 	xfr->difflen = 0;
    339 	dns_diff_clear(&xfr->diff);
    340 	if (xfr->maxrecords != 0U) {
    341 		result = dns_db_getsize(xfr->db, xfr->ver, &records, NULL);
    342 		if (result == ISC_R_SUCCESS && records > xfr->maxrecords) {
    343 			result = DNS_R_TOOMANYRECORDS;
    344 			goto failure;
    345 		}
    346 	}
    347 	result = ISC_R_SUCCESS;
    348 failure:
    349 	return (result);
    350 }
    351 
    352 static isc_result_t
    353 axfr_commit(dns_xfrin_ctx_t *xfr) {
    354 	isc_result_t result;
    355 
    356 	CHECK(axfr_apply(xfr));
    357 	CHECK(dns_db_endload(xfr->db, &xfr->axfr));
    358 	CHECK(dns_zone_verifydb(xfr->zone, xfr->db, NULL));
    359 
    360 	result = ISC_R_SUCCESS;
    361 failure:
    362 	return (result);
    363 }
    364 
    365 static isc_result_t
    366 axfr_finalize(dns_xfrin_ctx_t *xfr) {
    367 	isc_result_t result;
    368 
    369 	CHECK(dns_zone_replacedb(xfr->zone, xfr->db, true));
    370 
    371 	result = ISC_R_SUCCESS;
    372 failure:
    373 	return (result);
    374 }
    375 
    376 /**************************************************************************/
    377 /*
    378  * IXFR handling
    379  */
    380 
    381 static isc_result_t
    382 ixfr_init(dns_xfrin_ctx_t *xfr) {
    383 	isc_result_t result;
    384 	char *journalfile;
    385 
    386 	if (xfr->reqtype != dns_rdatatype_ixfr) {
    387 		xfrin_log(xfr, ISC_LOG_ERROR,
    388 			  "got incremental response to AXFR request");
    389 		return (DNS_R_FORMERR);
    390 	}
    391 
    392 	xfr->is_ixfr = true;
    393 	INSIST(xfr->db != NULL);
    394 	xfr->difflen = 0;
    395 
    396 	journalfile = dns_zone_getjournal(xfr->zone);
    397 	if (journalfile != NULL) {
    398 		CHECK(dns_journal_open(xfr->mctx, journalfile,
    399 				       DNS_JOURNAL_CREATE, &xfr->ixfr.journal));
    400 	}
    401 
    402 	result = ISC_R_SUCCESS;
    403 failure:
    404 	return (result);
    405 }
    406 
    407 static isc_result_t
    408 ixfr_putdata(dns_xfrin_ctx_t *xfr, dns_diffop_t op, dns_name_t *name,
    409 	     dns_ttl_t ttl, dns_rdata_t *rdata) {
    410 	isc_result_t result;
    411 	dns_difftuple_t *tuple = NULL;
    412 
    413 	if (rdata->rdclass != xfr->rdclass) {
    414 		return (DNS_R_BADCLASS);
    415 	}
    416 
    417 	if (op == DNS_DIFFOP_ADD) {
    418 		CHECK(dns_zone_checknames(xfr->zone, name, rdata));
    419 	}
    420 	CHECK(dns_difftuple_create(xfr->diff.mctx, op, name, ttl, rdata,
    421 				   &tuple));
    422 	dns_diff_append(&xfr->diff, &tuple);
    423 	if (++xfr->difflen > 100) {
    424 		CHECK(ixfr_apply(xfr));
    425 	}
    426 	result = ISC_R_SUCCESS;
    427 failure:
    428 	return (result);
    429 }
    430 
    431 /*
    432  * Apply a set of IXFR changes to the database.
    433  */
    434 static isc_result_t
    435 ixfr_apply(dns_xfrin_ctx_t *xfr) {
    436 	isc_result_t result;
    437 	uint64_t records;
    438 
    439 	if (xfr->ver == NULL) {
    440 		CHECK(dns_db_newversion(xfr->db, &xfr->ver));
    441 		if (xfr->ixfr.journal != NULL) {
    442 			CHECK(dns_journal_begin_transaction(xfr->ixfr.journal));
    443 		}
    444 	}
    445 	CHECK(dns_diff_apply(&xfr->diff, xfr->db, xfr->ver));
    446 	if (xfr->maxrecords != 0U) {
    447 		result = dns_db_getsize(xfr->db, xfr->ver, &records, NULL);
    448 		if (result == ISC_R_SUCCESS && records > xfr->maxrecords) {
    449 			result = DNS_R_TOOMANYRECORDS;
    450 			goto failure;
    451 		}
    452 	}
    453 	if (xfr->ixfr.journal != NULL) {
    454 		result = dns_journal_writediff(xfr->ixfr.journal, &xfr->diff);
    455 		if (result != ISC_R_SUCCESS) {
    456 			goto failure;
    457 		}
    458 	}
    459 	dns_diff_clear(&xfr->diff);
    460 	xfr->difflen = 0;
    461 	result = ISC_R_SUCCESS;
    462 failure:
    463 	return (result);
    464 }
    465 
    466 static isc_result_t
    467 ixfr_commit(dns_xfrin_ctx_t *xfr) {
    468 	isc_result_t result;
    469 
    470 	CHECK(ixfr_apply(xfr));
    471 	if (xfr->ver != NULL) {
    472 		CHECK(dns_zone_verifydb(xfr->zone, xfr->db, xfr->ver));
    473 		/* XXX enter ready-to-commit state here */
    474 		if (xfr->ixfr.journal != NULL) {
    475 			CHECK(dns_journal_commit(xfr->ixfr.journal));
    476 		}
    477 		dns_db_closeversion(xfr->db, &xfr->ver, true);
    478 		dns_zone_markdirty(xfr->zone);
    479 	}
    480 	result = ISC_R_SUCCESS;
    481 failure:
    482 	return (result);
    483 }
    484 
    485 /**************************************************************************/
    486 /*
    487  * Common AXFR/IXFR protocol code
    488  */
    489 
    490 /*
    491  * Handle a single incoming resource record according to the current
    492  * state.
    493  */
    494 static isc_result_t
    495 xfr_rr(dns_xfrin_ctx_t *xfr, dns_name_t *name, uint32_t ttl,
    496        dns_rdata_t *rdata) {
    497 	isc_result_t result;
    498 
    499 	xfr->nrecs++;
    500 
    501 	if (rdata->type == dns_rdatatype_none ||
    502 	    dns_rdatatype_ismeta(rdata->type)) {
    503 		FAIL(DNS_R_FORMERR);
    504 	}
    505 
    506 	/*
    507 	 * Immediately reject the entire transfer if the RR that is currently
    508 	 * being processed is an SOA record that is not placed at the zone
    509 	 * apex.
    510 	 */
    511 	if (rdata->type == dns_rdatatype_soa &&
    512 	    !dns_name_equal(&xfr->name, name)) {
    513 		char namebuf[DNS_NAME_FORMATSIZE];
    514 		dns_name_format(name, namebuf, sizeof(namebuf));
    515 		xfrin_log(xfr, ISC_LOG_DEBUG(3), "SOA name mismatch: '%s'",
    516 			  namebuf);
    517 		FAIL(DNS_R_NOTZONETOP);
    518 	}
    519 
    520 redo:
    521 	switch (xfr->state) {
    522 	case XFRST_SOAQUERY:
    523 		if (rdata->type != dns_rdatatype_soa) {
    524 			xfrin_log(xfr, ISC_LOG_ERROR,
    525 				  "non-SOA response to SOA query");
    526 			FAIL(DNS_R_FORMERR);
    527 		}
    528 		xfr->end_serial = dns_soa_getserial(rdata);
    529 		if (!DNS_SERIAL_GT(xfr->end_serial, xfr->ixfr.request_serial) &&
    530 		    !dns_zone_isforced(xfr->zone))
    531 		{
    532 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
    533 				  "requested serial %u, "
    534 				  "master has %u, not updating",
    535 				  xfr->ixfr.request_serial, xfr->end_serial);
    536 			FAIL(DNS_R_UPTODATE);
    537 		}
    538 		xfr->state = XFRST_GOTSOA;
    539 		break;
    540 
    541 	case XFRST_GOTSOA:
    542 		/*
    543 		 * Skip other records in the answer section.
    544 		 */
    545 		break;
    546 
    547 	case XFRST_INITIALSOA:
    548 		if (rdata->type != dns_rdatatype_soa) {
    549 			xfrin_log(xfr, ISC_LOG_ERROR,
    550 				  "first RR in zone transfer must be SOA");
    551 			FAIL(DNS_R_FORMERR);
    552 		}
    553 		/*
    554 		 * Remember the serial number in the initial SOA.
    555 		 * We need it to recognize the end of an IXFR.
    556 		 */
    557 		xfr->end_serial = dns_soa_getserial(rdata);
    558 		if (xfr->reqtype == dns_rdatatype_ixfr &&
    559 		    !DNS_SERIAL_GT(xfr->end_serial, xfr->ixfr.request_serial) &&
    560 		    !dns_zone_isforced(xfr->zone))
    561 		{
    562 			/*
    563 			 * This must be the single SOA record that is
    564 			 * sent when the current version on the master
    565 			 * is not newer than the version in the request.
    566 			 */
    567 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
    568 				  "requested serial %u, "
    569 				  "master has %u, not updating",
    570 				  xfr->ixfr.request_serial, xfr->end_serial);
    571 			FAIL(DNS_R_UPTODATE);
    572 		}
    573 		if (xfr->reqtype == dns_rdatatype_axfr) {
    574 			xfr->checkid = false;
    575 		}
    576 		xfr->firstsoa = *rdata;
    577 		if (xfr->firstsoa_data != NULL) {
    578 			isc_mem_free(xfr->mctx, xfr->firstsoa_data);
    579 		}
    580 		xfr->firstsoa_data = isc_mem_allocate(xfr->mctx, rdata->length);
    581 		memcpy(xfr->firstsoa_data, rdata->data, rdata->length);
    582 		xfr->firstsoa.data = xfr->firstsoa_data;
    583 		xfr->state = XFRST_FIRSTDATA;
    584 		break;
    585 
    586 	case XFRST_FIRSTDATA:
    587 		/*
    588 		 * If the transfer begins with one SOA record, it is an AXFR,
    589 		 * if it begins with two SOAs, it is an IXFR.
    590 		 */
    591 		if (xfr->reqtype == dns_rdatatype_ixfr &&
    592 		    rdata->type == dns_rdatatype_soa &&
    593 		    xfr->ixfr.request_serial == dns_soa_getserial(rdata))
    594 		{
    595 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
    596 				  "got incremental response");
    597 			CHECK(ixfr_init(xfr));
    598 			xfr->state = XFRST_IXFR_DELSOA;
    599 		} else {
    600 			xfrin_log(xfr, ISC_LOG_DEBUG(3),
    601 				  "got nonincremental response");
    602 			CHECK(axfr_init(xfr));
    603 			xfr->state = XFRST_AXFR;
    604 		}
    605 		goto redo;
    606 
    607 	case XFRST_IXFR_DELSOA:
    608 		INSIST(rdata->type == dns_rdatatype_soa);
    609 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_DEL, name, ttl, rdata));
    610 		xfr->state = XFRST_IXFR_DEL;
    611 		break;
    612 
    613 	case XFRST_IXFR_DEL:
    614 		if (rdata->type == dns_rdatatype_soa) {
    615 			uint32_t soa_serial = dns_soa_getserial(rdata);
    616 			xfr->state = XFRST_IXFR_ADDSOA;
    617 			xfr->ixfr.current_serial = soa_serial;
    618 			goto redo;
    619 		}
    620 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_DEL, name, ttl, rdata));
    621 		break;
    622 
    623 	case XFRST_IXFR_ADDSOA:
    624 		INSIST(rdata->type == dns_rdatatype_soa);
    625 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_ADD, name, ttl, rdata));
    626 		xfr->state = XFRST_IXFR_ADD;
    627 		break;
    628 
    629 	case XFRST_IXFR_ADD:
    630 		if (rdata->type == dns_rdatatype_soa) {
    631 			uint32_t soa_serial = dns_soa_getserial(rdata);
    632 			if (soa_serial == xfr->end_serial) {
    633 				CHECK(ixfr_commit(xfr));
    634 				xfr->state = XFRST_IXFR_END;
    635 				break;
    636 			} else if (soa_serial != xfr->ixfr.current_serial) {
    637 				xfrin_log(xfr, ISC_LOG_ERROR,
    638 					  "IXFR out of sync: "
    639 					  "expected serial %u, got %u",
    640 					  xfr->ixfr.current_serial, soa_serial);
    641 				FAIL(DNS_R_FORMERR);
    642 			} else {
    643 				CHECK(ixfr_commit(xfr));
    644 				xfr->state = XFRST_IXFR_DELSOA;
    645 				goto redo;
    646 			}
    647 		}
    648 		if (rdata->type == dns_rdatatype_ns &&
    649 		    dns_name_iswildcard(name)) {
    650 			FAIL(DNS_R_INVALIDNS);
    651 		}
    652 		CHECK(ixfr_putdata(xfr, DNS_DIFFOP_ADD, name, ttl, rdata));
    653 		break;
    654 
    655 	case XFRST_AXFR:
    656 		/*
    657 		 * Old BINDs sent cross class A records for non IN classes.
    658 		 */
    659 		if (rdata->type == dns_rdatatype_a &&
    660 		    rdata->rdclass != xfr->rdclass &&
    661 		    xfr->rdclass != dns_rdataclass_in)
    662 		{
    663 			break;
    664 		}
    665 		CHECK(axfr_putdata(xfr, DNS_DIFFOP_ADD, name, ttl, rdata));
    666 		if (rdata->type == dns_rdatatype_soa) {
    667 			/*
    668 			 * Use dns_rdata_compare instead of memcmp to
    669 			 * allow for case differences.
    670 			 */
    671 			if (dns_rdata_compare(rdata, &xfr->firstsoa) != 0) {
    672 				xfrin_log(xfr, ISC_LOG_ERROR,
    673 					  "start and ending SOA records "
    674 					  "mismatch");
    675 				FAIL(DNS_R_FORMERR);
    676 			}
    677 			CHECK(axfr_commit(xfr));
    678 			xfr->state = XFRST_AXFR_END;
    679 			break;
    680 		}
    681 		break;
    682 	case XFRST_AXFR_END:
    683 	case XFRST_IXFR_END:
    684 		FAIL(DNS_R_EXTRADATA);
    685 	/* NOTREACHED */
    686 	/* FALLTHROUGH */
    687 	default:
    688 		INSIST(0);
    689 		ISC_UNREACHABLE();
    690 	}
    691 	result = ISC_R_SUCCESS;
    692 failure:
    693 	return (result);
    694 }
    695 
    696 isc_result_t
    697 dns_xfrin_create(dns_zone_t *zone, dns_rdatatype_t xfrtype,
    698 		 const isc_sockaddr_t *masteraddr,
    699 		 const isc_sockaddr_t *sourceaddr, isc_dscp_t dscp,
    700 		 dns_tsigkey_t *tsigkey, isc_mem_t *mctx,
    701 		 isc_timermgr_t *timermgr, isc_socketmgr_t *socketmgr,
    702 		 isc_task_t *task, dns_xfrindone_t done,
    703 		 dns_xfrin_ctx_t **xfrp) {
    704 	dns_name_t *zonename = dns_zone_getorigin(zone);
    705 	dns_xfrin_ctx_t *xfr = NULL;
    706 	isc_result_t result;
    707 	dns_db_t *db = NULL;
    708 
    709 	REQUIRE(xfrp != NULL && *xfrp == NULL);
    710 
    711 	(void)dns_zone_getdb(zone, &db);
    712 
    713 	if (xfrtype == dns_rdatatype_soa || xfrtype == dns_rdatatype_ixfr) {
    714 		REQUIRE(db != NULL);
    715 	}
    716 
    717 	CHECK(xfrin_create(mctx, zone, db, task, timermgr, socketmgr, zonename,
    718 			   dns_zone_getclass(zone), xfrtype, masteraddr,
    719 			   sourceaddr, dscp, tsigkey, &xfr));
    720 
    721 	if (db != NULL) {
    722 		xfr->zone_had_db = true;
    723 	}
    724 
    725 	CHECK(xfrin_start(xfr));
    726 
    727 	xfr->done = done;
    728 	if (xfr->done != NULL) {
    729 		xfr->refcount++;
    730 	}
    731 	*xfrp = xfr;
    732 
    733 failure:
    734 	if (db != NULL) {
    735 		dns_db_detach(&db);
    736 	}
    737 	if (result != ISC_R_SUCCESS) {
    738 		char zonetext[DNS_NAME_MAXTEXT + 32];
    739 		dns_zone_name(zone, zonetext, sizeof(zonetext));
    740 		xfrin_log1(ISC_LOG_ERROR, zonetext, masteraddr,
    741 			   "zone transfer setup failed");
    742 	}
    743 	return (result);
    744 }
    745 
    746 void
    747 dns_xfrin_shutdown(dns_xfrin_ctx_t *xfr) {
    748 	if (!xfr->shuttingdown) {
    749 		xfrin_fail(xfr, ISC_R_CANCELED, "shut down");
    750 	}
    751 }
    752 
    753 void
    754 dns_xfrin_attach(dns_xfrin_ctx_t *source, dns_xfrin_ctx_t **target) {
    755 	REQUIRE(target != NULL && *target == NULL);
    756 	source->refcount++;
    757 	*target = source;
    758 }
    759 
    760 void
    761 dns_xfrin_detach(dns_xfrin_ctx_t **xfrp) {
    762 	dns_xfrin_ctx_t *xfr = *xfrp;
    763 	*xfrp = NULL;
    764 	INSIST(xfr->refcount > 0);
    765 	xfr->refcount--;
    766 	maybe_free(xfr);
    767 }
    768 
    769 static void
    770 xfrin_cancelio(dns_xfrin_ctx_t *xfr) {
    771 	if (xfr->connects > 0) {
    772 		isc_socket_cancel(xfr->socket, xfr->task,
    773 				  ISC_SOCKCANCEL_CONNECT);
    774 	} else if (xfr->recvs > 0) {
    775 		dns_tcpmsg_cancelread(&xfr->tcpmsg);
    776 	} else if (xfr->sends > 0) {
    777 		isc_socket_cancel(xfr->socket, xfr->task, ISC_SOCKCANCEL_SEND);
    778 	}
    779 }
    780 
    781 static void
    782 xfrin_reset(dns_xfrin_ctx_t *xfr) {
    783 	REQUIRE(VALID_XFRIN(xfr));
    784 
    785 	xfrin_log(xfr, ISC_LOG_INFO, "resetting");
    786 
    787 	xfrin_cancelio(xfr);
    788 
    789 	if (xfr->socket != NULL) {
    790 		isc_socket_detach(&xfr->socket);
    791 	}
    792 
    793 	if (xfr->lasttsig != NULL) {
    794 		isc_buffer_free(&xfr->lasttsig);
    795 	}
    796 
    797 	dns_diff_clear(&xfr->diff);
    798 	xfr->difflen = 0;
    799 
    800 	if (xfr->ixfr.journal != NULL) {
    801 		dns_journal_destroy(&xfr->ixfr.journal);
    802 	}
    803 
    804 	if (xfr->axfr.add_private != NULL) {
    805 		(void)dns_db_endload(xfr->db, &xfr->axfr);
    806 	}
    807 
    808 	if (xfr->tcpmsg_valid) {
    809 		dns_tcpmsg_invalidate(&xfr->tcpmsg);
    810 		xfr->tcpmsg_valid = false;
    811 	}
    812 
    813 	if (xfr->ver != NULL) {
    814 		dns_db_closeversion(xfr->db, &xfr->ver, false);
    815 	}
    816 }
    817 
    818 static void
    819 xfrin_fail(dns_xfrin_ctx_t *xfr, isc_result_t result, const char *msg) {
    820 	if (result != DNS_R_UPTODATE && result != DNS_R_TOOMANYRECORDS) {
    821 		xfrin_log(xfr, ISC_LOG_ERROR, "%s: %s", msg,
    822 			  isc_result_totext(result));
    823 		if (xfr->is_ixfr) {
    824 			/* Pass special result code to force AXFR retry */
    825 			result = DNS_R_BADIXFR;
    826 		}
    827 	}
    828 	xfrin_cancelio(xfr);
    829 	/*
    830 	 * Close the journal.
    831 	 */
    832 	if (xfr->ixfr.journal != NULL) {
    833 		dns_journal_destroy(&xfr->ixfr.journal);
    834 	}
    835 	if (xfr->done != NULL) {
    836 		(xfr->done)(xfr->zone, result);
    837 		xfr->done = NULL;
    838 	}
    839 	xfr->shuttingdown = true;
    840 	xfr->shutdown_result = result;
    841 	maybe_free(xfr);
    842 }
    843 
    844 static isc_result_t
    845 xfrin_create(isc_mem_t *mctx, dns_zone_t *zone, dns_db_t *db, isc_task_t *task,
    846 	     isc_timermgr_t *timermgr, isc_socketmgr_t *socketmgr,
    847 	     dns_name_t *zonename, dns_rdataclass_t rdclass,
    848 	     dns_rdatatype_t reqtype, const isc_sockaddr_t *masteraddr,
    849 	     const isc_sockaddr_t *sourceaddr, isc_dscp_t dscp,
    850 	     dns_tsigkey_t *tsigkey, dns_xfrin_ctx_t **xfrp) {
    851 	dns_xfrin_ctx_t *xfr = NULL;
    852 	isc_result_t result;
    853 
    854 	xfr = isc_mem_get(mctx, sizeof(*xfr));
    855 	xfr->mctx = NULL;
    856 	isc_mem_attach(mctx, &xfr->mctx);
    857 	xfr->refcount = 0;
    858 	xfr->zone = NULL;
    859 	dns_zone_iattach(zone, &xfr->zone);
    860 	xfr->task = NULL;
    861 	isc_task_attach(task, &xfr->task);
    862 	xfr->timer = NULL;
    863 	xfr->socketmgr = socketmgr;
    864 	xfr->done = NULL;
    865 
    866 	xfr->connects = 0;
    867 	xfr->sends = 0;
    868 	xfr->recvs = 0;
    869 	xfr->shuttingdown = false;
    870 	xfr->shutdown_result = ISC_R_UNSET;
    871 
    872 	dns_name_init(&xfr->name, NULL);
    873 	xfr->rdclass = rdclass;
    874 	xfr->checkid = true;
    875 	xfr->logit = true;
    876 	xfr->id = (dns_messageid_t)isc_random16();
    877 	xfr->reqtype = reqtype;
    878 	xfr->dscp = dscp;
    879 
    880 	/* sockaddr */
    881 	xfr->socket = NULL;
    882 	/* qbuffer */
    883 	/* qbuffer_data */
    884 	/* tcpmsg */
    885 	xfr->tcpmsg_valid = false;
    886 
    887 	xfr->zone_had_db = false;
    888 	xfr->db = NULL;
    889 	if (db != NULL) {
    890 		dns_db_attach(db, &xfr->db);
    891 	}
    892 	xfr->ver = NULL;
    893 	dns_diff_init(xfr->mctx, &xfr->diff);
    894 	xfr->difflen = 0;
    895 
    896 	if (reqtype == dns_rdatatype_soa) {
    897 		xfr->state = XFRST_SOAQUERY;
    898 	} else {
    899 		xfr->state = XFRST_INITIALSOA;
    900 	}
    901 	/* end_serial */
    902 
    903 	xfr->nmsg = 0;
    904 	xfr->nrecs = 0;
    905 	xfr->nbytes = 0;
    906 	xfr->maxrecords = dns_zone_getmaxrecords(zone);
    907 	isc_time_now(&xfr->start);
    908 
    909 	xfr->tsigkey = NULL;
    910 	if (tsigkey != NULL) {
    911 		dns_tsigkey_attach(tsigkey, &xfr->tsigkey);
    912 	}
    913 	xfr->lasttsig = NULL;
    914 	xfr->tsigctx = NULL;
    915 	xfr->sincetsig = 0;
    916 	xfr->is_ixfr = false;
    917 
    918 	/* ixfr.request_serial */
    919 	/* ixfr.current_serial */
    920 	xfr->ixfr.journal = NULL;
    921 
    922 	xfr->axfr.add = NULL;
    923 	xfr->axfr.add_private = NULL;
    924 	dns_rdata_init(&xfr->firstsoa);
    925 	xfr->firstsoa_data = NULL;
    926 
    927 	dns_name_dup(zonename, mctx, &xfr->name);
    928 
    929 	CHECK(isc_timer_create(timermgr, isc_timertype_inactive, NULL, NULL,
    930 			       task, xfrin_timeout, xfr, &xfr->timer));
    931 	CHECK(dns_timer_setidle(xfr->timer, dns_zone_getmaxxfrin(xfr->zone),
    932 				dns_zone_getidlein(xfr->zone), false));
    933 
    934 	xfr->masteraddr = *masteraddr;
    935 
    936 	INSIST(isc_sockaddr_pf(masteraddr) == isc_sockaddr_pf(sourceaddr));
    937 	xfr->sourceaddr = *sourceaddr;
    938 	isc_sockaddr_setport(&xfr->sourceaddr, 0);
    939 
    940 	/*
    941 	 * Reserve 2 bytes for TCP length at the beginning of the buffer.
    942 	 */
    943 	isc_buffer_init(&xfr->qbuffer, &xfr->qbuffer_data[2],
    944 			sizeof(xfr->qbuffer_data) - 2);
    945 
    946 	xfr->magic = XFRIN_MAGIC;
    947 	*xfrp = xfr;
    948 	return (ISC_R_SUCCESS);
    949 
    950 failure:
    951 	if (xfr->timer != NULL) {
    952 		isc_timer_detach(&xfr->timer);
    953 	}
    954 	if (dns_name_dynamic(&xfr->name)) {
    955 		dns_name_free(&xfr->name, xfr->mctx);
    956 	}
    957 	if (xfr->tsigkey != NULL) {
    958 		dns_tsigkey_detach(&xfr->tsigkey);
    959 	}
    960 	if (xfr->db != NULL) {
    961 		dns_db_detach(&xfr->db);
    962 	}
    963 	isc_task_detach(&xfr->task);
    964 	dns_zone_idetach(&xfr->zone);
    965 	isc_mem_putanddetach(&xfr->mctx, xfr, sizeof(*xfr));
    966 
    967 	return (result);
    968 }
    969 
    970 static isc_result_t
    971 xfrin_start(dns_xfrin_ctx_t *xfr) {
    972 	isc_result_t result;
    973 	CHECK(isc_socket_create(xfr->socketmgr,
    974 				isc_sockaddr_pf(&xfr->sourceaddr),
    975 				isc_sockettype_tcp, &xfr->socket));
    976 	isc_socket_setname(xfr->socket, "xfrin", NULL);
    977 #ifndef BROKEN_TCP_BIND_BEFORE_CONNECT
    978 	CHECK(isc_socket_bind(xfr->socket, &xfr->sourceaddr,
    979 			      ISC_SOCKET_REUSEADDRESS));
    980 #endif /* ifndef BROKEN_TCP_BIND_BEFORE_CONNECT */
    981 	isc_socket_dscp(xfr->socket, xfr->dscp);
    982 	CHECK(isc_socket_connect(xfr->socket, &xfr->masteraddr, xfr->task,
    983 				 xfrin_connect_done, xfr));
    984 	xfr->connects++;
    985 	return (ISC_R_SUCCESS);
    986 failure:
    987 	xfrin_fail(xfr, result, "failed setting up socket");
    988 	return (result);
    989 }
    990 
    991 /* XXX the resolver could use this, too */
    992 
    993 static isc_result_t
    994 render(dns_message_t *msg, isc_mem_t *mctx, isc_buffer_t *buf) {
    995 	dns_compress_t cctx;
    996 	bool cleanup_cctx = false;
    997 	isc_result_t result;
    998 
    999 	CHECK(dns_compress_init(&cctx, -1, mctx));
   1000 	cleanup_cctx = true;
   1001 	CHECK(dns_message_renderbegin(msg, &cctx, buf));
   1002 	CHECK(dns_message_rendersection(msg, DNS_SECTION_QUESTION, 0));
   1003 	CHECK(dns_message_rendersection(msg, DNS_SECTION_ANSWER, 0));
   1004 	CHECK(dns_message_rendersection(msg, DNS_SECTION_AUTHORITY, 0));
   1005 	CHECK(dns_message_rendersection(msg, DNS_SECTION_ADDITIONAL, 0));
   1006 	CHECK(dns_message_renderend(msg));
   1007 	result = ISC_R_SUCCESS;
   1008 failure:
   1009 	if (cleanup_cctx) {
   1010 		dns_compress_invalidate(&cctx);
   1011 	}
   1012 	return (result);
   1013 }
   1014 
   1015 /*
   1016  * A connection has been established.
   1017  */
   1018 static void
   1019 xfrin_connect_done(isc_task_t *task, isc_event_t *event) {
   1020 	isc_socket_connev_t *cev = (isc_socket_connev_t *)event;
   1021 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *)event->ev_arg;
   1022 	isc_result_t result = cev->result;
   1023 	char sourcetext[ISC_SOCKADDR_FORMATSIZE];
   1024 	char signerbuf[DNS_NAME_FORMATSIZE];
   1025 	const char *signer = "", *sep = "";
   1026 	isc_sockaddr_t sockaddr;
   1027 	dns_zonemgr_t *zmgr;
   1028 	isc_time_t now;
   1029 
   1030 	REQUIRE(VALID_XFRIN(xfr));
   1031 
   1032 	UNUSED(task);
   1033 
   1034 	INSIST(event->ev_type == ISC_SOCKEVENT_CONNECT);
   1035 	isc_event_free(&event);
   1036 
   1037 	xfr->connects--;
   1038 	if (xfr->shuttingdown) {
   1039 		maybe_free(xfr);
   1040 		return;
   1041 	}
   1042 
   1043 	zmgr = dns_zone_getmgr(xfr->zone);
   1044 	if (zmgr != NULL) {
   1045 		if (result != ISC_R_SUCCESS) {
   1046 			TIME_NOW(&now);
   1047 			dns_zonemgr_unreachableadd(zmgr, &xfr->masteraddr,
   1048 						   &xfr->sourceaddr, &now);
   1049 			goto failure;
   1050 		} else {
   1051 			dns_zonemgr_unreachabledel(zmgr, &xfr->masteraddr,
   1052 						   &xfr->sourceaddr);
   1053 		}
   1054 	}
   1055 
   1056 	result = isc_socket_getsockname(xfr->socket, &sockaddr);
   1057 	if (result == ISC_R_SUCCESS) {
   1058 		isc_sockaddr_format(&sockaddr, sourcetext, sizeof(sourcetext));
   1059 	} else {
   1060 		strlcpy(sourcetext, "<UNKNOWN>", sizeof(sourcetext));
   1061 	}
   1062 
   1063 	if (xfr->tsigkey != NULL && xfr->tsigkey->key != NULL) {
   1064 		dns_name_format(dst_key_name(xfr->tsigkey->key), signerbuf,
   1065 				sizeof(signerbuf));
   1066 		sep = " TSIG ";
   1067 		signer = signerbuf;
   1068 	}
   1069 
   1070 	xfrin_log(xfr, ISC_LOG_INFO, "connected using %s%s%s", sourcetext, sep,
   1071 		  signer);
   1072 
   1073 	dns_tcpmsg_init(xfr->mctx, xfr->socket, &xfr->tcpmsg);
   1074 	xfr->tcpmsg_valid = true;
   1075 
   1076 	CHECK(xfrin_send_request(xfr));
   1077 failure:
   1078 	if (result != ISC_R_SUCCESS) {
   1079 		xfrin_fail(xfr, result, "failed to connect");
   1080 	}
   1081 }
   1082 
   1083 /*
   1084  * Convert a tuple into a dns_name_t suitable for inserting
   1085  * into the given dns_message_t.
   1086  */
   1087 static isc_result_t
   1088 tuple2msgname(dns_difftuple_t *tuple, dns_message_t *msg, dns_name_t **target) {
   1089 	isc_result_t result;
   1090 	dns_rdata_t *rdata = NULL;
   1091 	dns_rdatalist_t *rdl = NULL;
   1092 	dns_rdataset_t *rds = NULL;
   1093 	dns_name_t *name = NULL;
   1094 
   1095 	REQUIRE(target != NULL && *target == NULL);
   1096 
   1097 	CHECK(dns_message_gettemprdata(msg, &rdata));
   1098 	dns_rdata_init(rdata);
   1099 	dns_rdata_clone(&tuple->rdata, rdata);
   1100 
   1101 	CHECK(dns_message_gettemprdatalist(msg, &rdl));
   1102 	dns_rdatalist_init(rdl);
   1103 	rdl->type = tuple->rdata.type;
   1104 	rdl->rdclass = tuple->rdata.rdclass;
   1105 	rdl->ttl = tuple->ttl;
   1106 	ISC_LIST_APPEND(rdl->rdata, rdata, link);
   1107 
   1108 	CHECK(dns_message_gettemprdataset(msg, &rds));
   1109 	CHECK(dns_rdatalist_tordataset(rdl, rds));
   1110 
   1111 	CHECK(dns_message_gettempname(msg, &name));
   1112 	dns_name_clone(&tuple->name, name);
   1113 	ISC_LIST_APPEND(name->list, rds, link);
   1114 
   1115 	*target = name;
   1116 	return (ISC_R_SUCCESS);
   1117 
   1118 failure:
   1119 
   1120 	if (rds != NULL) {
   1121 		dns_rdataset_disassociate(rds);
   1122 		dns_message_puttemprdataset(msg, &rds);
   1123 	}
   1124 	if (rdl != NULL) {
   1125 		ISC_LIST_UNLINK(rdl->rdata, rdata, link);
   1126 		dns_message_puttemprdatalist(msg, &rdl);
   1127 	}
   1128 	if (rdata != NULL) {
   1129 		dns_message_puttemprdata(msg, &rdata);
   1130 	}
   1131 
   1132 	return (result);
   1133 }
   1134 
   1135 /*
   1136  * Build an *XFR request and send its length prefix.
   1137  */
   1138 static isc_result_t
   1139 xfrin_send_request(dns_xfrin_ctx_t *xfr) {
   1140 	isc_result_t result;
   1141 	isc_region_t region;
   1142 	dns_rdataset_t *qrdataset = NULL;
   1143 	dns_message_t *msg = NULL;
   1144 	dns_difftuple_t *soatuple = NULL;
   1145 	dns_name_t *qname = NULL;
   1146 	dns_dbversion_t *ver = NULL;
   1147 	dns_name_t *msgsoaname = NULL;
   1148 
   1149 	/* Create the request message */
   1150 	dns_message_create(xfr->mctx, DNS_MESSAGE_INTENTRENDER, &msg);
   1151 	CHECK(dns_message_settsigkey(msg, xfr->tsigkey));
   1152 
   1153 	/* Create a name for the question section. */
   1154 	CHECK(dns_message_gettempname(msg, &qname));
   1155 	dns_name_clone(&xfr->name, qname);
   1156 
   1157 	/* Formulate the question and attach it to the question name. */
   1158 	CHECK(dns_message_gettemprdataset(msg, &qrdataset));
   1159 	dns_rdataset_makequestion(qrdataset, xfr->rdclass, xfr->reqtype);
   1160 	ISC_LIST_APPEND(qname->list, qrdataset, link);
   1161 	qrdataset = NULL;
   1162 
   1163 	dns_message_addname(msg, qname, DNS_SECTION_QUESTION);
   1164 	qname = NULL;
   1165 
   1166 	if (xfr->reqtype == dns_rdatatype_ixfr) {
   1167 		/* Get the SOA and add it to the authority section. */
   1168 		/* XXX is using the current version the right thing? */
   1169 		dns_db_currentversion(xfr->db, &ver);
   1170 		CHECK(dns_db_createsoatuple(xfr->db, ver, xfr->mctx,
   1171 					    DNS_DIFFOP_EXISTS, &soatuple));
   1172 		xfr->ixfr.request_serial = dns_soa_getserial(&soatuple->rdata);
   1173 		xfr->ixfr.current_serial = xfr->ixfr.request_serial;
   1174 		xfrin_log(xfr, ISC_LOG_DEBUG(3),
   1175 			  "requesting IXFR for serial %u",
   1176 			  xfr->ixfr.request_serial);
   1177 
   1178 		CHECK(tuple2msgname(soatuple, msg, &msgsoaname));
   1179 		dns_message_addname(msg, msgsoaname, DNS_SECTION_AUTHORITY);
   1180 	} else if (xfr->reqtype == dns_rdatatype_soa) {
   1181 		CHECK(dns_db_getsoaserial(xfr->db, NULL,
   1182 					  &xfr->ixfr.request_serial));
   1183 	}
   1184 
   1185 	xfr->checkid = true;
   1186 	xfr->logit = true;
   1187 	xfr->id++;
   1188 	xfr->nmsg = 0;
   1189 	xfr->nrecs = 0;
   1190 	xfr->nbytes = 0;
   1191 	isc_time_now(&xfr->start);
   1192 	msg->id = xfr->id;
   1193 	if (xfr->tsigctx != NULL) {
   1194 		dst_context_destroy(&xfr->tsigctx);
   1195 	}
   1196 
   1197 	CHECK(render(msg, xfr->mctx, &xfr->qbuffer));
   1198 
   1199 	/*
   1200 	 * Free the last tsig, if there is one.
   1201 	 */
   1202 	if (xfr->lasttsig != NULL) {
   1203 		isc_buffer_free(&xfr->lasttsig);
   1204 	}
   1205 
   1206 	/*
   1207 	 * Save the query TSIG and don't let message_destroy free it.
   1208 	 */
   1209 	CHECK(dns_message_getquerytsig(msg, xfr->mctx, &xfr->lasttsig));
   1210 
   1211 	isc_buffer_usedregion(&xfr->qbuffer, &region);
   1212 	INSIST(region.length <= 65535);
   1213 
   1214 	/*
   1215 	 * Record message length and adjust region to include TCP
   1216 	 * length field.
   1217 	 */
   1218 	xfr->qbuffer_data[0] = (region.length >> 8) & 0xff;
   1219 	xfr->qbuffer_data[1] = region.length & 0xff;
   1220 	region.base -= 2;
   1221 	region.length += 2;
   1222 	CHECK(isc_socket_send(xfr->socket, &region, xfr->task, xfrin_send_done,
   1223 			      xfr));
   1224 	xfr->sends++;
   1225 
   1226 failure:
   1227 	if (qname != NULL) {
   1228 		dns_message_puttempname(msg, &qname);
   1229 	}
   1230 	if (qrdataset != NULL) {
   1231 		dns_message_puttemprdataset(msg, &qrdataset);
   1232 	}
   1233 	if (msg != NULL) {
   1234 		dns_message_detach(&msg);
   1235 	}
   1236 	if (soatuple != NULL) {
   1237 		dns_difftuple_free(&soatuple);
   1238 	}
   1239 	if (ver != NULL) {
   1240 		dns_db_closeversion(xfr->db, &ver, false);
   1241 	}
   1242 	return (result);
   1243 }
   1244 
   1245 static void
   1246 xfrin_send_done(isc_task_t *task, isc_event_t *event) {
   1247 	isc_socketevent_t *sev = (isc_socketevent_t *)event;
   1248 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *)event->ev_arg;
   1249 	isc_result_t result;
   1250 
   1251 	REQUIRE(VALID_XFRIN(xfr));
   1252 
   1253 	UNUSED(task);
   1254 
   1255 	INSIST(event->ev_type == ISC_SOCKEVENT_SENDDONE);
   1256 
   1257 	xfr->sends--;
   1258 	xfrin_log(xfr, ISC_LOG_DEBUG(3), "sent request data");
   1259 	CHECK(sev->result);
   1260 
   1261 	CHECK(dns_tcpmsg_readmessage(&xfr->tcpmsg, xfr->task, xfrin_recv_done,
   1262 				     xfr));
   1263 	xfr->recvs++;
   1264 failure:
   1265 	isc_event_free(&event);
   1266 	if (result != ISC_R_SUCCESS) {
   1267 		xfrin_fail(xfr, result, "failed sending request data");
   1268 	}
   1269 }
   1270 
   1271 static void
   1272 xfrin_recv_done(isc_task_t *task, isc_event_t *ev) {
   1273 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *)ev->ev_arg;
   1274 	isc_result_t result;
   1275 	dns_message_t *msg = NULL;
   1276 	dns_name_t *name;
   1277 	dns_tcpmsg_t *tcpmsg;
   1278 	const dns_name_t *tsigowner = NULL;
   1279 
   1280 	REQUIRE(VALID_XFRIN(xfr));
   1281 
   1282 	UNUSED(task);
   1283 
   1284 	INSIST(ev->ev_type == DNS_EVENT_TCPMSG);
   1285 	tcpmsg = ev->ev_sender;
   1286 	isc_event_free(&ev);
   1287 
   1288 	xfr->recvs--;
   1289 	if (xfr->shuttingdown) {
   1290 		maybe_free(xfr);
   1291 		return;
   1292 	}
   1293 
   1294 	CHECK(tcpmsg->result);
   1295 
   1296 	xfrin_log(xfr, ISC_LOG_DEBUG(7), "received %u bytes",
   1297 		  tcpmsg->buffer.used);
   1298 
   1299 	CHECK(isc_timer_touch(xfr->timer));
   1300 
   1301 	dns_message_create(xfr->mctx, DNS_MESSAGE_INTENTPARSE, &msg);
   1302 
   1303 	CHECK(dns_message_settsigkey(msg, xfr->tsigkey));
   1304 	CHECK(dns_message_setquerytsig(msg, xfr->lasttsig));
   1305 
   1306 	msg->tsigctx = xfr->tsigctx;
   1307 	xfr->tsigctx = NULL;
   1308 
   1309 	dns_message_setclass(msg, xfr->rdclass);
   1310 
   1311 	if (xfr->nmsg > 0) {
   1312 		msg->tcp_continuation = 1;
   1313 	}
   1314 
   1315 	result = dns_message_parse(msg, &tcpmsg->buffer,
   1316 				   DNS_MESSAGEPARSE_PRESERVEORDER);
   1317 
   1318 	if (result == ISC_R_SUCCESS) {
   1319 		dns_message_logpacket(msg, "received message from",
   1320 				      &tcpmsg->address, DNS_LOGCATEGORY_XFER_IN,
   1321 				      DNS_LOGMODULE_XFER_IN, ISC_LOG_DEBUG(10),
   1322 				      xfr->mctx);
   1323 	} else {
   1324 		xfrin_log(xfr, ISC_LOG_DEBUG(10), "dns_message_parse: %s",
   1325 			  dns_result_totext(result));
   1326 	}
   1327 
   1328 	if (result != ISC_R_SUCCESS || msg->rcode != dns_rcode_noerror ||
   1329 	    msg->opcode != dns_opcode_query || msg->rdclass != xfr->rdclass ||
   1330 	    (xfr->checkid && msg->id != xfr->id))
   1331 	{
   1332 		if (result == ISC_R_SUCCESS && msg->rcode != dns_rcode_noerror)
   1333 		{
   1334 			result = ISC_RESULTCLASS_DNSRCODE + msg->rcode; /*XXX*/
   1335 		} else if (result == ISC_R_SUCCESS &&
   1336 			   msg->opcode != dns_opcode_query) {
   1337 			result = DNS_R_UNEXPECTEDOPCODE;
   1338 		} else if (result == ISC_R_SUCCESS &&
   1339 			   msg->rdclass != xfr->rdclass) {
   1340 			result = DNS_R_BADCLASS;
   1341 		} else if (result == ISC_R_SUCCESS || result == DNS_R_NOERROR) {
   1342 			result = DNS_R_UNEXPECTEDID;
   1343 		}
   1344 		if (xfr->reqtype == dns_rdatatype_axfr ||
   1345 		    xfr->reqtype == dns_rdatatype_soa) {
   1346 			goto failure;
   1347 		}
   1348 		xfrin_log(xfr, ISC_LOG_DEBUG(3), "got %s, retrying with AXFR",
   1349 			  isc_result_totext(result));
   1350 	try_axfr:
   1351 		dns_message_detach(&msg);
   1352 		xfrin_reset(xfr);
   1353 		xfr->reqtype = dns_rdatatype_soa;
   1354 		xfr->state = XFRST_SOAQUERY;
   1355 		(void)xfrin_start(xfr);
   1356 		return;
   1357 	} else if (!xfr->checkid && msg->id != xfr->id && xfr->logit) {
   1358 		xfrin_log(xfr, ISC_LOG_WARNING,
   1359 			  "detected message ID mismatch on incoming AXFR "
   1360 			  "stream, transfer will fail in BIND 9.17.2 and "
   1361 			  "later if AXFR source is not fixed");
   1362 		xfr->logit = false;
   1363 	}
   1364 
   1365 	/*
   1366 	 * Does the server know about IXFR?  If it doesn't we will get
   1367 	 * a message with a empty answer section or a potentially a CNAME /
   1368 	 * DNAME, the later is handled by xfr_rr() which will return FORMERR
   1369 	 * if the first RR in the answer section is not a SOA record.
   1370 	 */
   1371 	if (xfr->reqtype == dns_rdatatype_ixfr &&
   1372 	    xfr->state == XFRST_INITIALSOA &&
   1373 	    msg->counts[DNS_SECTION_ANSWER] == 0)
   1374 	{
   1375 		xfrin_log(xfr, ISC_LOG_DEBUG(3),
   1376 			  "empty answer section, retrying with AXFR");
   1377 		goto try_axfr;
   1378 	}
   1379 
   1380 	if (xfr->reqtype == dns_rdatatype_soa &&
   1381 	    (msg->flags & DNS_MESSAGEFLAG_AA) == 0) {
   1382 		FAIL(DNS_R_NOTAUTHORITATIVE);
   1383 	}
   1384 
   1385 	result = dns_message_checksig(msg, dns_zone_getview(xfr->zone));
   1386 	if (result != ISC_R_SUCCESS) {
   1387 		xfrin_log(xfr, ISC_LOG_DEBUG(3), "TSIG check failed: %s",
   1388 			  isc_result_totext(result));
   1389 		goto failure;
   1390 	}
   1391 
   1392 	for (result = dns_message_firstname(msg, DNS_SECTION_ANSWER);
   1393 	     result == ISC_R_SUCCESS;
   1394 	     result = dns_message_nextname(msg, DNS_SECTION_ANSWER))
   1395 	{
   1396 		dns_rdataset_t *rds;
   1397 
   1398 		name = NULL;
   1399 		dns_message_currentname(msg, DNS_SECTION_ANSWER, &name);
   1400 		for (rds = ISC_LIST_HEAD(name->list); rds != NULL;
   1401 		     rds = ISC_LIST_NEXT(rds, link))
   1402 		{
   1403 			for (result = dns_rdataset_first(rds);
   1404 			     result == ISC_R_SUCCESS;
   1405 			     result = dns_rdataset_next(rds))
   1406 			{
   1407 				dns_rdata_t rdata = DNS_RDATA_INIT;
   1408 				dns_rdataset_current(rds, &rdata);
   1409 				CHECK(xfr_rr(xfr, name, rds->ttl, &rdata));
   1410 			}
   1411 		}
   1412 	}
   1413 	if (result != ISC_R_NOMORE) {
   1414 		goto failure;
   1415 	}
   1416 
   1417 	if (dns_message_gettsig(msg, &tsigowner) != NULL) {
   1418 		/*
   1419 		 * Reset the counter.
   1420 		 */
   1421 		xfr->sincetsig = 0;
   1422 
   1423 		/*
   1424 		 * Free the last tsig, if there is one.
   1425 		 */
   1426 		if (xfr->lasttsig != NULL) {
   1427 			isc_buffer_free(&xfr->lasttsig);
   1428 		}
   1429 
   1430 		/*
   1431 		 * Update the last tsig pointer.
   1432 		 */
   1433 		CHECK(dns_message_getquerytsig(msg, xfr->mctx, &xfr->lasttsig));
   1434 	} else if (dns_message_gettsigkey(msg) != NULL) {
   1435 		xfr->sincetsig++;
   1436 		if (xfr->sincetsig > 100 || xfr->nmsg == 0 ||
   1437 		    xfr->state == XFRST_AXFR_END ||
   1438 		    xfr->state == XFRST_IXFR_END)
   1439 		{
   1440 			result = DNS_R_EXPECTEDTSIG;
   1441 			goto failure;
   1442 		}
   1443 	}
   1444 
   1445 	/*
   1446 	 * Update the number of messages received.
   1447 	 */
   1448 	xfr->nmsg++;
   1449 
   1450 	/*
   1451 	 * Update the number of bytes received.
   1452 	 */
   1453 	xfr->nbytes += tcpmsg->buffer.used;
   1454 
   1455 	/*
   1456 	 * Take the context back.
   1457 	 */
   1458 	INSIST(xfr->tsigctx == NULL);
   1459 	xfr->tsigctx = msg->tsigctx;
   1460 	msg->tsigctx = NULL;
   1461 
   1462 	dns_message_detach(&msg);
   1463 
   1464 	switch (xfr->state) {
   1465 	case XFRST_GOTSOA:
   1466 		xfr->reqtype = dns_rdatatype_axfr;
   1467 		xfr->state = XFRST_INITIALSOA;
   1468 		CHECK(xfrin_send_request(xfr));
   1469 		break;
   1470 	case XFRST_AXFR_END:
   1471 		CHECK(axfr_finalize(xfr));
   1472 	/* FALLTHROUGH */
   1473 	case XFRST_IXFR_END:
   1474 		/*
   1475 		 * Close the journal.
   1476 		 */
   1477 		if (xfr->ixfr.journal != NULL) {
   1478 			dns_journal_destroy(&xfr->ixfr.journal);
   1479 		}
   1480 
   1481 		/*
   1482 		 * Inform the caller we succeeded.
   1483 		 */
   1484 		if (xfr->done != NULL) {
   1485 			(xfr->done)(xfr->zone, ISC_R_SUCCESS);
   1486 			xfr->done = NULL;
   1487 		}
   1488 		/*
   1489 		 * We should have no outstanding events at this
   1490 		 * point, thus maybe_free() should succeed.
   1491 		 */
   1492 		xfr->shuttingdown = true;
   1493 		xfr->shutdown_result = ISC_R_SUCCESS;
   1494 		maybe_free(xfr);
   1495 		break;
   1496 	default:
   1497 		/*
   1498 		 * Read the next message.
   1499 		 */
   1500 		CHECK(dns_tcpmsg_readmessage(&xfr->tcpmsg, xfr->task,
   1501 					     xfrin_recv_done, xfr));
   1502 		xfr->recvs++;
   1503 	}
   1504 	return;
   1505 
   1506 failure:
   1507 	if (msg != NULL) {
   1508 		dns_message_detach(&msg);
   1509 	}
   1510 	if (result != ISC_R_SUCCESS) {
   1511 		xfrin_fail(xfr, result, "failed while receiving responses");
   1512 	}
   1513 }
   1514 
   1515 static void
   1516 xfrin_timeout(isc_task_t *task, isc_event_t *event) {
   1517 	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *)event->ev_arg;
   1518 
   1519 	REQUIRE(VALID_XFRIN(xfr));
   1520 
   1521 	UNUSED(task);
   1522 
   1523 	isc_event_free(&event);
   1524 	/*
   1525 	 * This will log "giving up: timeout".
   1526 	 */
   1527 	xfrin_fail(xfr, ISC_R_TIMEDOUT, "giving up");
   1528 }
   1529 
   1530 static void
   1531 maybe_free(dns_xfrin_ctx_t *xfr) {
   1532 	uint64_t msecs;
   1533 	uint64_t persec;
   1534 	const char *result_str;
   1535 
   1536 	REQUIRE(VALID_XFRIN(xfr));
   1537 
   1538 	if (!xfr->shuttingdown || xfr->refcount != 0 || xfr->connects != 0 ||
   1539 	    xfr->sends != 0 || xfr->recvs != 0)
   1540 	{
   1541 		return;
   1542 	}
   1543 
   1544 	INSIST(!xfr->shuttingdown || xfr->shutdown_result != ISC_R_UNSET);
   1545 
   1546 	/* If we're called through dns_xfrin_detach() and are not
   1547 	 * shutting down, we can't know what the transfer status is as
   1548 	 * we are only called when the last reference is lost.
   1549 	 */
   1550 	result_str = (xfr->shuttingdown
   1551 			      ? isc_result_totext(xfr->shutdown_result)
   1552 			      : "unknown");
   1553 	xfrin_log(xfr, ISC_LOG_INFO, "Transfer status: %s", result_str);
   1554 
   1555 	/*
   1556 	 * Calculate the length of time the transfer took,
   1557 	 * and print a log message with the bytes and rate.
   1558 	 */
   1559 	isc_time_now(&xfr->end);
   1560 	msecs = isc_time_microdiff(&xfr->end, &xfr->start) / 1000;
   1561 	if (msecs == 0) {
   1562 		msecs = 1;
   1563 	}
   1564 	persec = (xfr->nbytes * 1000) / msecs;
   1565 	xfrin_log(xfr, ISC_LOG_INFO,
   1566 		  "Transfer completed: %d messages, %d records, "
   1567 		  "%" PRIu64 " bytes, "
   1568 		  "%u.%03u secs (%u bytes/sec) (serial %u)",
   1569 		  xfr->nmsg, xfr->nrecs, xfr->nbytes,
   1570 		  (unsigned int)(msecs / 1000), (unsigned int)(msecs % 1000),
   1571 		  (unsigned int)persec, xfr->end_serial);
   1572 
   1573 	if (xfr->socket != NULL) {
   1574 		isc_socket_detach(&xfr->socket);
   1575 	}
   1576 
   1577 	if (xfr->timer != NULL) {
   1578 		isc_timer_detach(&xfr->timer);
   1579 	}
   1580 
   1581 	if (xfr->task != NULL) {
   1582 		isc_task_detach(&xfr->task);
   1583 	}
   1584 
   1585 	if (xfr->tsigkey != NULL) {
   1586 		dns_tsigkey_detach(&xfr->tsigkey);
   1587 	}
   1588 
   1589 	if (xfr->lasttsig != NULL) {
   1590 		isc_buffer_free(&xfr->lasttsig);
   1591 	}
   1592 
   1593 	dns_diff_clear(&xfr->diff);
   1594 
   1595 	if (xfr->ixfr.journal != NULL) {
   1596 		dns_journal_destroy(&xfr->ixfr.journal);
   1597 	}
   1598 
   1599 	if (xfr->axfr.add_private != NULL) {
   1600 		(void)dns_db_endload(xfr->db, &xfr->axfr);
   1601 	}
   1602 
   1603 	if (xfr->tcpmsg_valid) {
   1604 		dns_tcpmsg_invalidate(&xfr->tcpmsg);
   1605 	}
   1606 
   1607 	if (xfr->tsigctx != NULL) {
   1608 		dst_context_destroy(&xfr->tsigctx);
   1609 	}
   1610 
   1611 	if ((xfr->name.attributes & DNS_NAMEATTR_DYNAMIC) != 0) {
   1612 		dns_name_free(&xfr->name, xfr->mctx);
   1613 	}
   1614 
   1615 	if (xfr->ver != NULL) {
   1616 		dns_db_closeversion(xfr->db, &xfr->ver, false);
   1617 	}
   1618 
   1619 	if (xfr->db != NULL) {
   1620 		dns_db_detach(&xfr->db);
   1621 	}
   1622 
   1623 	if (xfr->zone != NULL) {
   1624 		if (!xfr->zone_had_db && xfr->shuttingdown &&
   1625 		    xfr->shutdown_result == ISC_R_SUCCESS &&
   1626 		    dns_zone_gettype(xfr->zone) == dns_zone_mirror)
   1627 		{
   1628 			dns_zone_log(xfr->zone, ISC_LOG_INFO,
   1629 				     "mirror zone is now in use");
   1630 		}
   1631 		xfrin_log(xfr, ISC_LOG_DEBUG(99), "freeing transfer context");
   1632 		/*
   1633 		 * xfr->zone must not be detached before xfrin_log() is called.
   1634 		 */
   1635 		dns_zone_idetach(&xfr->zone);
   1636 	}
   1637 
   1638 	if (xfr->firstsoa_data != NULL) {
   1639 		isc_mem_free(xfr->mctx, xfr->firstsoa_data);
   1640 	}
   1641 
   1642 	isc_mem_putanddetach(&xfr->mctx, xfr, sizeof(*xfr));
   1643 }
   1644 
   1645 /*
   1646  * Log incoming zone transfer messages in a format like
   1647  * transfer of <zone> from <address>: <message>
   1648  */
   1649 static void
   1650 xfrin_logv(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
   1651 	   const char *fmt, va_list ap) {
   1652 	char mastertext[ISC_SOCKADDR_FORMATSIZE];
   1653 	char msgtext[2048];
   1654 
   1655 	isc_sockaddr_format(masteraddr, mastertext, sizeof(mastertext));
   1656 	vsnprintf(msgtext, sizeof(msgtext), fmt, ap);
   1657 
   1658 	isc_log_write(dns_lctx, DNS_LOGCATEGORY_XFER_IN, DNS_LOGMODULE_XFER_IN,
   1659 		      level, "transfer of '%s' from %s: %s", zonetext,
   1660 		      mastertext, msgtext);
   1661 }
   1662 
   1663 /*
   1664  * Logging function for use when a xfrin_ctx_t has not yet been created.
   1665  */
   1666 
   1667 static void
   1668 xfrin_log1(int level, const char *zonetext, const isc_sockaddr_t *masteraddr,
   1669 	   const char *fmt, ...) {
   1670 	va_list ap;
   1671 
   1672 	if (!isc_log_wouldlog(dns_lctx, level)) {
   1673 		return;
   1674 	}
   1675 
   1676 	va_start(ap, fmt);
   1677 	xfrin_logv(level, zonetext, masteraddr, fmt, ap);
   1678 	va_end(ap);
   1679 }
   1680 
   1681 /*
   1682  * Logging function for use when there is a xfrin_ctx_t.
   1683  */
   1684 
   1685 static void
   1686 xfrin_log(dns_xfrin_ctx_t *xfr, int level, const char *fmt, ...) {
   1687 	va_list ap;
   1688 	char zonetext[DNS_NAME_MAXTEXT + 32];
   1689 
   1690 	if (!isc_log_wouldlog(dns_lctx, level)) {
   1691 		return;
   1692 	}
   1693 
   1694 	dns_zone_name(xfr->zone, zonetext, sizeof(zonetext));
   1695 
   1696 	va_start(ap, fmt);
   1697 	xfrin_logv(level, zonetext, &xfr->masteraddr, fmt, ap);
   1698 	va_end(ap);
   1699 }
   1700