2 * Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1998-2003 Internet Software Consortium.
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
18 /* $Id: rdata.h,v 1.77 2009-12-04 21:09:33 marka Exp $ */
29 * Provides facilities for manipulating DNS rdata, including conversions to
30 * and from wire format and text format.
32 * Given the large amount of rdata possible in a nameserver, it was important
33 * to come up with a very efficient way of storing rdata, but at the same
34 * time allow it to be manipulated.
36 * The decision was to store rdata in uncompressed wire format,
37 * and not to make it a fully abstracted object; i.e. certain parts of the
38 * server know rdata is stored that way. This saves a lot of memory, and
39 * makes adding rdata to messages easy. Having much of the server know
40 * the representation would be perilous, and we certainly don't want each
41 * user of rdata to be manipulating such a low-level structure. This is
42 * where the rdata module comes in. The module allows rdata handles to be
43 * created and attached to uncompressed wire format regions. All rdata
44 * operations and conversions are done through these handles.
46 * Implementation Notes:
48 *\li The routines in this module are expected to be synthesized by the
49 * build process from a set of source files, one per rdata type. For
50 * portability, it's probably best that the building be done by a C
51 * program. Adding a new rdata type will be a simple matter of adding
52 * a file to a directory and rebuilding the server. *All* knowledge of
53 * the format of a particular rdata type is in this file.
56 *\li Clients of this module must impose any required synchronization.
59 *\li This module deals with low-level byte streams. Errors in any of
60 * the functions are likely to crash the server or corrupt memory.
62 *\li Rdata is typed, and the caller must know what type of rdata it has.
63 * A caller that gets this wrong could crash the server.
65 *\li The fromstruct() and tostruct() routines use a void * pointer to
66 * represent the structure. The caller must ensure that it passes a
67 * pointer to the appropriate type, or the server could crash or memory
76 * dns_rdata_fromwire() deals with raw network data. An error in
77 * this routine could result in the failure or hijacking of the server.
83 *\li Draft Binary Labels (2)
84 *\li Draft Local Compression (1)
85 *\li Various RFCs for particular types; these will be documented in the
86 * sources files of the types.
96 #include <dns/types.h>
98 #include <dns/message.h>
108 ***** An 'rdata' is a handle to a binary region. The handle has an RR
109 ***** class and type, and the data in the binary region is in the format
110 ***** of the given class and type.
113 * Clients are strongly discouraged from using this type directly, with
114 * the exception of the 'link' field which may be used directly for whatever
115 * purpose the client desires.
118 unsigned char * data;
120 dns_rdataclass_t rdclass;
121 dns_rdatatype_t type;
123 ISC_LINK(dns_rdata_t) link;
126 #define DNS_RDATA_INIT { NULL, 0, 0, 0, 0, {(void*)(-1), (void *)(-1)}}
128 #define DNS_RDATA_CHECKINITIALIZED
129 #ifdef DNS_RDATA_CHECKINITIALIZED
130 #define DNS_RDATA_INITIALIZED(rdata) \
131 ((rdata)->data == NULL && (rdata)->length == 0 && \
132 (rdata)->rdclass == 0 && (rdata)->type == 0 && (rdata)->flags == 0 && \
133 !ISC_LINK_LINKED((rdata), link))
135 #ifdef ISC_LIST_CHECKINIT
136 #define DNS_RDATA_INITIALIZED(rdata) \
137 (!ISC_LINK_LINKED((rdata), link))
139 #define DNS_RDATA_INITIALIZED(rdata) ISC_TRUE
143 #define DNS_RDATA_UPDATE 0x0001 /*%< update pseudo record. */
144 #define DNS_RDATA_OFFLINE 0x0002 /*%< RRSIG has a offline key. */
146 #define DNS_RDATA_VALIDFLAGS(rdata) \
147 (((rdata)->flags & ~(DNS_RDATA_UPDATE|DNS_RDATA_OFFLINE)) == 0)
150 * Flags affecting rdata formatting style. Flags 0xFFFF0000
151 * are used by masterfile-level formatting and defined elsewhere.
152 * See additional comments at dns_rdata_tofmttext().
155 /*% Split the rdata into multiple lines to try to keep it
156 within the "width". */
157 #define DNS_STYLEFLAG_MULTILINE 0x00000001U
159 /*% Output explanatory comments. */
160 #define DNS_STYLEFLAG_COMMENT 0x00000002U
162 #define DNS_RDATA_DOWNCASE DNS_NAME_DOWNCASE
163 #define DNS_RDATA_CHECKNAMES DNS_NAME_CHECKNAMES
164 #define DNS_RDATA_CHECKNAMESFAIL DNS_NAME_CHECKNAMESFAIL
165 #define DNS_RDATA_CHECKREVERSE DNS_NAME_CHECKREVERSE
166 #define DNS_RDATA_CHECKMX DNS_NAME_CHECKMX
167 #define DNS_RDATA_CHECKMXFAIL DNS_NAME_CHECKMXFAIL
174 dns_rdata_init(dns_rdata_t *rdata);
176 * Make 'rdata' empty.
179 * 'rdata' is a valid rdata (i.e. not NULL, points to a struct dns_rdata)
183 dns_rdata_reset(dns_rdata_t *rdata);
185 * Make 'rdata' empty.
188 *\li 'rdata' is a previously initialized rdata and is not linked.
192 dns_rdata_clone(const dns_rdata_t *src, dns_rdata_t *target);
194 * Clone 'target' from 'src'.
197 *\li 'src' to be initialized.
198 *\li 'target' to be initialized.
206 dns_rdata_compare(const dns_rdata_t *rdata1, const dns_rdata_t *rdata2);
208 * Determine the relative ordering under the DNSSEC order relation of
209 * 'rdata1' and 'rdata2'.
213 *\li 'rdata1' is a valid, non-empty rdata
215 *\li 'rdata2' is a valid, non-empty rdata
218 *\li < 0 'rdata1' is less than 'rdata2'
219 *\li 0 'rdata1' is equal to 'rdata2'
220 *\li > 0 'rdata1' is greater than 'rdata2'
224 dns_rdata_casecompare(const dns_rdata_t *rdata1, const dns_rdata_t *rdata2);
226 * dns_rdata_casecompare() is similar to dns_rdata_compare() but also
227 * compares domain names case insensitively in known rdata types that
228 * are treated as opaque data by dns_rdata_compare().
232 *\li 'rdata1' is a valid, non-empty rdata
234 *\li 'rdata2' is a valid, non-empty rdata
237 *\li < 0 'rdata1' is less than 'rdata2'
238 *\li 0 'rdata1' is equal to 'rdata2'
239 *\li > 0 'rdata1' is greater than 'rdata2'
247 dns_rdata_fromregion(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
248 dns_rdatatype_t type, isc_region_t *r);
250 * Make 'rdata' refer to region 'r'.
254 *\li The data in 'r' is properly formatted for whatever type it is.
258 dns_rdata_toregion(const dns_rdata_t *rdata, isc_region_t *r);
260 * Make 'r' refer to 'rdata'.
264 dns_rdata_fromwire(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
265 dns_rdatatype_t type, isc_buffer_t *source,
266 dns_decompress_t *dctx, unsigned int options,
267 isc_buffer_t *target);
269 * Copy the possibly-compressed rdata at source into the target region.
272 *\li Name decompression policy is controlled by 'dctx'.
275 *\li DNS_RDATA_DOWNCASE downcase domain names when they are copied
280 *\li 'rdclass' and 'type' are valid.
282 *\li 'source' is a valid buffer, and the active region of 'source'
283 * references the rdata to be processed.
285 *\li 'target' is a valid buffer.
287 *\li 'dctx' is a valid decompression context.
290 * if result is success:
291 * \li If 'rdata' is not NULL, it is attached to the target.
292 * \li The conditions dns_name_fromwire() ensures for names hold
293 * for all names in the rdata.
294 * \li The current location in source is advanced, and the used space
295 * in target is updated.
299 *\li Any non-success status from dns_name_fromwire()
300 *\li Various 'Bad Form' class failures depending on class and type
301 *\li Bad Form: Input too short
302 *\li Resource Limit: Not enough space
306 dns_rdata_towire(dns_rdata_t *rdata, dns_compress_t *cctx,
307 isc_buffer_t *target);
309 * Convert 'rdata' into wire format, compressing it as specified by the
310 * compression context 'cctx', and storing the result in 'target'.
313 *\li If the compression context allows global compression, then the
314 * global compression table may be updated.
317 *\li 'rdata' is a valid, non-empty rdata
319 *\li target is a valid buffer
321 *\li Any offsets specified in a global compression table are valid
325 * if the result is success:
326 * \li The used space in target is updated.
330 *\li Any non-success status from dns_name_towire()
331 *\li Resource Limit: Not enough space
335 dns_rdata_fromtext(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
336 dns_rdatatype_t type, isc_lex_t *lexer, dns_name_t *origin,
337 unsigned int options, isc_mem_t *mctx,
338 isc_buffer_t *target, dns_rdatacallbacks_t *callbacks);
340 * Convert the textual representation of a DNS rdata into uncompressed wire
341 * form stored in the target region. Tokens constituting the text of the rdata
342 * are taken from 'lexer'.
345 *\li Relative domain names in the rdata will have 'origin' appended to them.
346 * A NULL origin implies "origin == dns_rootname".
350 *\li DNS_RDATA_DOWNCASE downcase domain names when they are copied
352 *\li DNS_RDATA_CHECKNAMES perform checknames checks.
353 *\li DNS_RDATA_CHECKNAMESFAIL fail if the checknames check fail. If
354 * not set a warning will be issued.
355 *\li DNS_RDATA_CHECKREVERSE this should set if the owner name ends
356 * in IP6.ARPA, IP6.INT or IN-ADDR.ARPA.
360 *\li 'rdclass' and 'type' are valid.
362 *\li 'lexer' is a valid isc_lex_t.
364 *\li 'mctx' is a valid isc_mem_t.
366 *\li 'target' is a valid region.
368 *\li 'origin' if non NULL it must be absolute.
370 *\li 'callbacks' to be NULL or callbacks->warn and callbacks->error be
374 * if result is success:
375 *\li If 'rdata' is not NULL, it is attached to the target.
377 *\li The conditions dns_name_fromtext() ensures for names hold
378 * for all names in the rdata.
380 *\li The used space in target is updated.
384 *\li Translated result codes from isc_lex_gettoken
385 *\li Various 'Bad Form' class failures depending on class and type
386 *\li Bad Form: Input too short
387 *\li Resource Limit: Not enough space
388 *\li Resource Limit: Not enough memory
392 dns_rdata_totext(dns_rdata_t *rdata, dns_name_t *origin, isc_buffer_t *target);
394 * Convert 'rdata' into text format, storing the result in 'target'.
395 * The text will consist of a single line, with fields separated by
399 *\li If 'origin' is not NULL, then any names in the rdata that are
400 * subdomains of 'origin' will be made relative it.
402 *\li XXX Do we *really* want to support 'origin'? I'm inclined towards "no"
407 *\li 'rdata' is a valid, non-empty rdata
409 *\li 'origin' is NULL, or is a valid name
411 *\li 'target' is a valid text buffer
414 * if the result is success:
416 * \li The used space in target is updated.
420 *\li Any non-success status from dns_name_totext()
421 *\li Resource Limit: Not enough space
425 dns_rdata_tofmttext(dns_rdata_t *rdata, dns_name_t *origin, unsigned int flags,
426 unsigned int width, const char *linebreak,
427 isc_buffer_t *target);
429 * Like dns_rdata_totext, but do formatted output suitable for
430 * database dumps. This is intended for use by dns_db_dump();
431 * library users are discouraged from calling it directly.
433 * If (flags & #DNS_STYLEFLAG_MULTILINE) != 0, attempt to stay
434 * within 'width' by breaking the text into multiple lines.
435 * The string 'linebreak' is inserted between lines, and parentheses
436 * are added when necessary. Because RRs contain unbreakable elements
437 * such as domain names whose length is variable, unpredictable, and
438 * potentially large, there is no guarantee that the lines will
439 * not exceed 'width' anyway.
441 * If (flags & #DNS_STYLEFLAG_MULTILINE) == 0, the rdata is always
442 * printed as a single line, and no parentheses are used.
443 * The 'width' and 'linebreak' arguments are ignored.
445 * If (flags & #DNS_STYLEFLAG_COMMENT) != 0, output explanatory
446 * comments next to things like the SOA timer fields. Some
447 * comments (e.g., the SOA ones) are only printed when multiline
448 * output is selected.
452 dns_rdata_fromstruct(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
453 dns_rdatatype_t type, void *source, isc_buffer_t *target);
455 * Convert the C structure representation of an rdata into uncompressed wire
456 * format in 'target'.
458 * XXX Should we have a 'size' parameter as a sanity check on target?
462 *\li 'rdclass' and 'type' are valid.
464 *\li 'source' points to a valid C struct for the class and type.
466 *\li 'target' is a valid buffer.
468 *\li All structure pointers to memory blocks should be NULL if their
469 * corresponding length values are zero.
472 * if result is success:
473 * \li If 'rdata' is not NULL, it is attached to the target.
475 * \li The used space in 'target' is updated.
479 *\li Various 'Bad Form' class failures depending on class and type
480 *\li Resource Limit: Not enough space
484 dns_rdata_tostruct(dns_rdata_t *rdata, void *target, isc_mem_t *mctx);
486 * Convert an rdata into its C structure representation.
488 * If 'mctx' is NULL then 'rdata' must persist while 'target' is being used.
490 * If 'mctx' is non NULL then memory will be allocated if required.
494 *\li 'rdata' is a valid, non-empty rdata.
496 *\li 'target' to point to a valid pointer for the type and class.
500 *\li Resource Limit: Not enough memory
504 dns_rdata_freestruct(void *source);
506 * Free dynamic memory attached to 'source' (if any).
510 *\li 'source' to point to the structure previously filled in by
511 * dns_rdata_tostruct().
515 dns_rdatatype_ismeta(dns_rdatatype_t type);
517 * Return true iff the rdata type 'type' is a meta-type
522 dns_rdatatype_issingleton(dns_rdatatype_t type);
524 * Return true iff the rdata type 'type' is a singleton type,
528 * \li 'type' is a valid rdata type.
533 dns_rdataclass_ismeta(dns_rdataclass_t rdclass);
535 * Return true iff the rdata class 'rdclass' is a meta-class
540 dns_rdatatype_isdnssec(dns_rdatatype_t type);
542 * Return true iff 'type' is one of the DNSSEC
543 * rdata types that may exist alongside a CNAME record.
546 * \li 'type' is a valid rdata type.
550 dns_rdatatype_iszonecutauth(dns_rdatatype_t type);
552 * Return true iff rdata of type 'type' is considered authoritative
553 * data (not glue) in the NSEC chain when it occurs in the parent zone
557 * \li 'type' is a valid rdata type.
562 dns_rdatatype_isknown(dns_rdatatype_t type);
564 * Return true iff the rdata type 'type' is known.
567 * \li 'type' is a valid rdata type.
573 dns_rdata_additionaldata(dns_rdata_t *rdata, dns_additionaldatafunc_t add,
576 * Call 'add' for each name and type from 'rdata' which is subject to
577 * additional section processing.
581 *\li 'rdata' is a valid, non-empty rdata.
583 *\li 'add' is a valid dns_additionalfunc_t.
587 *\li If successful, then add() will have been called for each name
588 * and type subject to additional section processing.
590 *\li If add() returns something other than #ISC_R_SUCCESS, that result
591 * will be returned as the result of dns_rdata_additionaldata().
597 *\li Many other results are possible if not successful.
601 dns_rdata_digest(dns_rdata_t *rdata, dns_digestfunc_t digest, void *arg);
603 * Send 'rdata' in DNSSEC canonical form to 'digest'.
606 *\li 'digest' may be called more than once by dns_rdata_digest(). The
607 * concatenation of all the regions, in the order they were given
608 * to 'digest', will be the DNSSEC canonical form of 'rdata'.
612 *\li 'rdata' is a valid, non-empty rdata.
614 *\li 'digest' is a valid dns_digestfunc_t.
618 *\li If successful, then all of the rdata's data has been sent, in
619 * DNSSEC canonical form, to 'digest'.
621 *\li If digest() returns something other than ISC_R_SUCCESS, that result
622 * will be returned as the result of dns_rdata_digest().
628 *\li Many other results are possible if not successful.
632 dns_rdatatype_questiononly(dns_rdatatype_t type);
634 * Return true iff rdata of type 'type' can only appear in the question
635 * section of a properly formatted message.
638 * \li 'type' is a valid rdata type.
643 dns_rdatatype_notquestion(dns_rdatatype_t type);
645 * Return true iff rdata of type 'type' can not appear in the question
646 * section of a properly formatted message.
649 * \li 'type' is a valid rdata type.
654 dns_rdatatype_atparent(dns_rdatatype_t type);
656 * Return true iff rdata of type 'type' should appear at the parent of
660 * \li 'type' is a valid rdata type.
665 dns_rdatatype_attributes(dns_rdatatype_t rdtype);
667 * Return attributes for the given type.
670 *\li 'rdtype' are known.
673 *\li a bitmask consisting of the following flags.
676 /*% only one may exist for a name */
677 #define DNS_RDATATYPEATTR_SINGLETON 0x00000001U
678 /*% requires no other data be present */
679 #define DNS_RDATATYPEATTR_EXCLUSIVE 0x00000002U
680 /*% Is a meta type */
681 #define DNS_RDATATYPEATTR_META 0x00000004U
682 /*% Is a DNSSEC type, like RRSIG or NSEC */
683 #define DNS_RDATATYPEATTR_DNSSEC 0x00000008U
684 /*% Is a zone cut authority type */
685 #define DNS_RDATATYPEATTR_ZONECUTAUTH 0x00000010U
686 /*% Is reserved (unusable) */
687 #define DNS_RDATATYPEATTR_RESERVED 0x00000020U
688 /*% Is an unknown type */
689 #define DNS_RDATATYPEATTR_UNKNOWN 0x00000040U
690 /*% Is META, and can only be in a question section */
691 #define DNS_RDATATYPEATTR_QUESTIONONLY 0x00000080U
692 /*% is META, and can NOT be in a question section */
693 #define DNS_RDATATYPEATTR_NOTQUESTION 0x00000100U
694 /*% Is present at zone cuts in the parent, not the child */
695 #define DNS_RDATATYPEATTR_ATPARENT 0x00000200U
698 dns_rdata_covers(dns_rdata_t *rdata);
700 * Return the rdatatype that this type covers.
703 *\li 'rdata' is a valid, non-empty rdata.
705 *\li 'rdata' is a type that covers other rdata types.
708 *\li The type covered.
712 dns_rdata_checkowner(dns_name_t* name, dns_rdataclass_t rdclass,
713 dns_rdatatype_t type, isc_boolean_t wildcard);
715 * Returns whether this is a valid ownername for this <type,class>.
716 * If wildcard is true allow the first label to be a wildcard if
720 * 'name' is a valid name.
724 dns_rdata_checknames(dns_rdata_t *rdata, dns_name_t *owner, dns_name_t *bad);
726 * Returns whether 'rdata' contains valid domain names. The checks are
727 * sensitive to the owner name.
729 * If 'bad' is non-NULL and a domain name fails the check the
730 * the offending name will be return in 'bad' by cloning from
731 * the 'rdata' contents.
734 * 'rdata' to be valid.
735 * 'owner' to be valid.
736 * 'bad' to be NULL or valid.
740 dns_rdata_exists(dns_rdata_t *rdata, dns_rdatatype_t type);
743 dns_rdata_notexist(dns_rdata_t *rdata, dns_rdatatype_t type);
746 dns_rdata_deleterrset(dns_rdata_t *rdata, dns_rdatatype_t type);
749 dns_rdata_makedelete(dns_rdata_t *rdata);
752 dns_rdata_updateop(dns_rdata_t *rdata, dns_section_t section);
756 #endif /* DNS_RDATA_H */