xref: /freebsd/contrib/unbound/services/localzone.h (revision c1d255d3ffdbe447de3ab875bf4e7d7accc5bfc5)
1 /*
2  * services/localzone.h - local zones authority service.
3  *
4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
5  *
6  * This software is open source.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * Redistributions of source code must retain the above copyright notice,
13  * this list of conditions and the following disclaimer.
14  *
15  * Redistributions in binary form must reproduce the above copyright notice,
16  * this list of conditions and the following disclaimer in the documentation
17  * and/or other materials provided with the distribution.
18  *
19  * Neither the name of the NLNET LABS nor the names of its contributors may
20  * be used to endorse or promote products derived from this software without
21  * specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 /**
37  * \file
38  *
39  * This file contains functions to enable local zone authority service.
40  */
41 
42 #ifndef SERVICES_LOCALZONE_H
43 #define SERVICES_LOCALZONE_H
44 #include "util/rbtree.h"
45 #include "util/locks.h"
46 #include "util/storage/dnstree.h"
47 #include "util/module.h"
48 #include "services/view.h"
49 #include "sldns/sbuffer.h"
50 struct packed_rrset_data;
51 struct ub_packed_rrset_key;
52 struct regional;
53 struct config_file;
54 struct edns_data;
55 struct query_info;
56 struct sldns_buffer;
57 struct comm_reply;
58 struct config_strlist;
59 
60 /**
61  * Local zone type
62  * This type determines processing for queries that did not match
63  * local-data directly.
64  */
65 enum localzone_type {
66 	/** unset type, used for unset tag_action elements */
67 	local_zone_unset = 0,
68 	/** drop query */
69 	local_zone_deny,
70 	/** answer with error */
71 	local_zone_refuse,
72 	/** answer nxdomain or nodata */
73 	local_zone_static,
74 	/** resolve normally */
75 	local_zone_transparent,
76 	/** do not block types at localdata names */
77 	local_zone_typetransparent,
78 	/** answer with data at zone apex */
79 	local_zone_redirect,
80 	/** remove default AS112 blocking contents for zone
81 	 * nodefault is used in config not during service. */
82 	local_zone_nodefault,
83 	/** log client address, but no block (transparent) */
84 	local_zone_inform,
85 	/** log client address, and block (drop) */
86 	local_zone_inform_deny,
87 	/** log client address, and direct */
88 	local_zone_inform_redirect,
89 	/** resolve normally, even when there is local data */
90 	local_zone_always_transparent,
91 	/** answer with error, even when there is local data */
92 	local_zone_always_refuse,
93 	/** answer with nxdomain, even when there is local data */
94 	local_zone_always_nxdomain,
95 	/** answer with noerror/nodata, even when there is local data */
96 	local_zone_always_nodata,
97 	/** drop query, even when there is local data */
98 	local_zone_always_deny,
99 	/** answer with 0.0.0.0 or ::0 or noerror/nodata, even when there is
100 	 * local data */
101 	local_zone_always_null,
102 	/** answer not from the view, but global or no-answer */
103 	local_zone_noview,
104 	/** Invalid type, cannot be used to generate answer */
105 	local_zone_invalid
106 };
107 
108 /**
109  * Authoritative local zones storage, shared.
110  */
111 struct local_zones {
112 	/** lock on the localzone tree */
113 	lock_rw_type lock;
114 	/** rbtree of struct local_zone */
115 	rbtree_type ztree;
116 };
117 
118 /**
119  * Local zone. A locally served authoritative zone.
120  */
121 struct local_zone {
122 	/** rbtree node, key is name and class */
123 	rbnode_type node;
124 	/** parent zone, if any. */
125 	struct local_zone* parent;
126 
127 	/** zone name, in uncompressed wireformat */
128 	uint8_t* name;
129 	/** length of zone name */
130 	size_t namelen;
131 	/** number of labels in zone name */
132 	int namelabs;
133 	/** the class of this zone.
134 	 * uses 'dclass' to not conflict with c++ keyword class. */
135 	uint16_t dclass;
136 
137 	/** lock on the data in the structure
138 	 * For the node, parent, name, namelen, namelabs, dclass, you
139 	 * need to also hold the zones_tree lock to change them (or to
140 	 * delete this zone) */
141 	lock_rw_type lock;
142 
143 	/** how to process zone */
144 	enum localzone_type type;
145 	/** tag bitlist */
146 	uint8_t* taglist;
147 	/** length of the taglist (in bytes) */
148 	size_t taglen;
149 	/** netblock addr_tree with struct local_zone_override information
150 	 * or NULL if there are no override elements */
151 	struct rbtree_type* override_tree;
152 
153 	/** in this region the zone's data is allocated.
154 	 * the struct local_zone itself is malloced. */
155 	struct regional* region;
156 	/** local data for this zone
157 	 * rbtree of struct local_data */
158 	rbtree_type data;
159 	/** if data contains zone apex SOA data, this is a ptr to it. */
160 	struct ub_packed_rrset_key* soa;
161 	/** if data contains zone apex SOA data, this is a ptr to an
162 	 * artificial negative SOA rrset (TTL is the minimum of the TTL and the
163 	 * SOA.MINIMUM). */
164 	struct ub_packed_rrset_key* soa_negative;
165 };
166 
167 /**
168  * Local data. One domain name, and the RRs to go with it.
169  */
170 struct local_data {
171 	/** rbtree node, key is name only */
172 	rbnode_type node;
173 	/** domain name */
174 	uint8_t* name;
175 	/** length of name */
176 	size_t namelen;
177 	/** number of labels in name */
178 	int namelabs;
179 	/** the data rrsets, with different types, linked list.
180 	 * If this list is NULL, the node is an empty non-terminal. */
181 	struct local_rrset* rrsets;
182 };
183 
184 /**
185  * A local data RRset
186  */
187 struct local_rrset {
188 	/** next in list */
189 	struct local_rrset* next;
190 	/** RRset data item */
191 	struct ub_packed_rrset_key* rrset;
192 };
193 
194 /**
195  * Local zone override information
196  */
197 struct local_zone_override {
198 	/** node in addrtree */
199 	struct addr_tree_node node;
200 	/** override for local zone type */
201 	enum localzone_type type;
202 };
203 
204 /**
205  * Create local zones storage
206  * @return new struct or NULL on error.
207  */
208 struct local_zones* local_zones_create(void);
209 
210 /**
211  * Delete local zones storage
212  * @param zones: to delete.
213  */
214 void local_zones_delete(struct local_zones* zones);
215 
216 /**
217  * Apply config settings; setup the local authoritative data.
218  * Takes care of locking.
219  * @param zones: is set up.
220  * @param cfg: config data.
221  * @return false on error.
222  */
223 int local_zones_apply_cfg(struct local_zones* zones, struct config_file* cfg);
224 
225 /**
226  * Compare two local_zone entries in rbtree. Sort hierarchical but not
227  * canonical
228  * @param z1: zone 1
229  * @param z2: zone 2
230  * @return: -1, 0, +1 comparison value.
231  */
232 int local_zone_cmp(const void* z1, const void* z2);
233 
234 /**
235  * Compare two local_data entries in rbtree. Sort canonical.
236  * @param d1: data 1
237  * @param d2: data 2
238  * @return: -1, 0, +1 comparison value.
239  */
240 int local_data_cmp(const void* d1, const void* d2);
241 
242 /**
243  * Delete one zone
244  * @param z: to delete.
245  */
246 void local_zone_delete(struct local_zone* z);
247 
248 /**
249  * Lookup zone that contains the given name, class and taglist.
250  * User must lock the tree or result zone.
251  * @param zones: the zones tree
252  * @param name: dname to lookup
253  * @param len: length of name.
254  * @param labs: labelcount of name.
255  * @param dclass: class to lookup.
256  * @param dtype: type to lookup, if type DS a zone higher is used for zonecuts.
257  * @param taglist: taglist to lookup.
258  * @param taglen: lenth of taglist.
259  * @param ignoretags: lookup zone by name and class, regardless the
260  * local-zone's tags.
261  * @return closest local_zone or NULL if no covering zone is found.
262  */
263 struct local_zone* local_zones_tags_lookup(struct local_zones* zones,
264 	uint8_t* name, size_t len, int labs, uint16_t dclass, uint16_t dtype,
265 	uint8_t* taglist, size_t taglen, int ignoretags);
266 
267 /**
268  * Lookup zone that contains the given name, class.
269  * User must lock the tree or result zone.
270  * @param zones: the zones tree
271  * @param name: dname to lookup
272  * @param len: length of name.
273  * @param labs: labelcount of name.
274  * @param dclass: class to lookup.
275  * @param dtype: type of the record, if type DS then a zone higher up is found
276  *   pass 0 to just plain find a zone for a name.
277  * @return closest local_zone or NULL if no covering zone is found.
278  */
279 struct local_zone* local_zones_lookup(struct local_zones* zones,
280 	uint8_t* name, size_t len, int labs, uint16_t dclass, uint16_t dtype);
281 
282 /**
283  * Debug helper. Print all zones
284  * Takes care of locking.
285  * @param zones: the zones tree
286  */
287 void local_zones_print(struct local_zones* zones);
288 
289 /**
290  * Answer authoritatively for local zones.
291  * Takes care of locking.
292  * @param zones: the stored zones (shared, read only).
293  * @param env: the module environment.
294  * @param qinfo: query info (parsed).
295  * @param edns: edns info (parsed).
296  * @param buf: buffer with query ID and flags, also for reply.
297  * @param temp: temporary storage region.
298  * @param repinfo: source address for checks. may be NULL.
299  * @param taglist: taglist for checks. May be NULL.
300  * @param taglen: length of the taglist.
301  * @param tagactions: local zone actions for tags. May be NULL.
302  * @param tagactionssize: length of the tagactions.
303  * @param tag_datas: array per tag of strlist with rdata strings. or NULL.
304  * @param tag_datas_size: size of tag_datas array.
305  * @param tagname: array of tag name strings (for debug output).
306  * @param num_tags: number of items in tagname array.
307  * @param view: answer using this view. May be NULL.
308  * @return true if answer is in buffer. false if query is not answered
309  * by authority data. If the reply should be dropped altogether, the return
310  * value is true, but the buffer is cleared (empty).
311  * It can also return true if a non-exact alias answer is found.  In this
312  * case qinfo->local_alias points to the corresponding alias RRset but the
313  * answer is NOT encoded in buffer.  It's the caller's responsibility to
314  * complete the alias chain (if needed) and encode the final set of answer.
315  * Data pointed to by qinfo->local_alias is allocated in 'temp' or refers to
316  * configuration data.  So the caller will need to make a deep copy of it
317  * if it needs to keep it beyond the lifetime of 'temp' or a dynamic update
318  * to local zone data.
319  */
320 int local_zones_answer(struct local_zones* zones, struct module_env* env,
321 	struct query_info* qinfo, struct edns_data* edns, struct sldns_buffer* buf,
322 	struct regional* temp, struct comm_reply* repinfo, uint8_t* taglist,
323 	size_t taglen, uint8_t* tagactions, size_t tagactionssize,
324 	struct config_strlist** tag_datas, size_t tag_datas_size,
325 	char** tagname, int num_tags, struct view* view);
326 
327 /**
328  * Answer using the local zone only (not local data used).
329  * @param z: zone for query.
330  * @param env: module environment.
331  * @param qinfo: query.
332  * @param edns: edns from query.
333  * @param repinfo: source address for checks. may be NULL.
334  * @param buf: buffer for answer.
335  * @param temp: temp region for encoding.
336  * @param ld: local data, if NULL, no such name exists in localdata.
337  * @param lz_type: type of the local zone.
338  * @return 1 if a reply is to be sent, 0 if not.
339  */
340 int
341 local_zones_zone_answer(struct local_zone* z, struct module_env* env,
342 	struct query_info* qinfo, struct edns_data* edns,
343 	struct comm_reply* repinfo, sldns_buffer* buf, struct regional* temp,
344 	struct local_data* ld, enum localzone_type lz_type);
345 
346 /**
347  * Parse the string into localzone type.
348  *
349  * @param str: string to parse
350  * @param t: local zone type returned here.
351  * @return 0 on parse error.
352  */
353 int local_zone_str2type(const char* str, enum localzone_type* t);
354 
355 /**
356  * Print localzone type to a string.  Pointer to a constant string.
357  *
358  * @param t: local zone type.
359  * @return constant string that describes type.
360  */
361 const char* local_zone_type2str(enum localzone_type t);
362 
363 /**
364  * Find zone that with exactly given name, class.
365  * User must lock the tree or result zone.
366  * @param zones: the zones tree
367  * @param name: dname to lookup
368  * @param len: length of name.
369  * @param labs: labelcount of name.
370  * @param dclass: class to lookup.
371  * @return the exact local_zone or NULL.
372  */
373 struct local_zone* local_zones_find(struct local_zones* zones,
374 	uint8_t* name, size_t len, int labs, uint16_t dclass);
375 
376 /**
377  * Find zone that with exactly or smaller name/class
378  * User must lock the tree or result zone.
379  * @param zones: the zones tree
380  * @param name: dname to lookup
381  * @param len: length of name.
382  * @param labs: labelcount of name.
383  * @param dclass: class to lookup.
384  * @param exact: 1 on return is this is an exact match.
385  * @return the exact or smaller local_zone or NULL.
386  */
387 struct local_zone*
388 local_zones_find_le(struct local_zones* zones,
389         uint8_t* name, size_t len, int labs, uint16_t dclass,
390 	int* exact);
391 
392 /**
393  * Add a new zone. Caller must hold the zones lock.
394  * Adjusts the other zones as well (parent pointers) after insertion.
395  * The zone must NOT exist (returns NULL and logs error).
396  * @param zones: the zones tree
397  * @param name: dname to add
398  * @param len: length of name.
399  * @param labs: labelcount of name.
400  * @param dclass: class to add.
401  * @param tp: type.
402  * @return local_zone or NULL on error, caller must printout memory error.
403  */
404 struct local_zone* local_zones_add_zone(struct local_zones* zones,
405 	uint8_t* name, size_t len, int labs, uint16_t dclass,
406 	enum localzone_type tp);
407 
408 /**
409  * Delete a zone. Caller must hold the zones lock.
410  * Adjusts the other zones as well (parent pointers) after insertion.
411  * @param zones: the zones tree
412  * @param zone: the zone to delete from tree. Also deletes zone from memory.
413  */
414 void local_zones_del_zone(struct local_zones* zones, struct local_zone* zone);
415 
416 /**
417  * Add RR data into the localzone data.
418  * Looks up the zone, if no covering zone, a transparent zone with the
419  * name of the RR is created.
420  * @param zones: the zones tree. Not locked by caller.
421  * @param rr: string with on RR.
422  * @return false on failure.
423  */
424 int local_zones_add_RR(struct local_zones* zones, const char* rr);
425 
426 /**
427  * Remove data from domain name in the tree.
428  * All types are removed. No effect if zone or name does not exist.
429  * @param zones: zones tree.
430  * @param name: dname to remove
431  * @param len: length of name.
432  * @param labs: labelcount of name.
433  * @param dclass: class to remove.
434  */
435 void local_zones_del_data(struct local_zones* zones,
436 	uint8_t* name, size_t len, int labs, uint16_t dclass);
437 
438 
439 /**
440  * Form wireformat from text format domain name.
441  * @param str: the domain name in text "www.example.com"
442  * @param res: resulting wireformat is stored here with malloc.
443  * @param len: length of resulting wireformat.
444  * @param labs: number of labels in resulting wireformat.
445  * @return false on error, syntax or memory. Also logged.
446  */
447 int parse_dname(const char* str, uint8_t** res, size_t* len, int* labs);
448 
449 /**
450  * Find local data tag string match for the given type (in qinfo) in the list.
451  * If found, 'r' will be filled with corresponding rrset information.
452  * @param qinfo: contains name, type, and class for the data
453  * @param list: stores local tag data to be searched
454  * @param r: rrset key to be filled for matched data
455  * @param temp: region to allocate rrset in 'r'
456  * @return 1 if a match is found and rrset is built; otherwise 0 including
457  * errors.
458  */
459 int local_data_find_tag_datas(const struct query_info* qinfo,
460 	struct config_strlist* list, struct ub_packed_rrset_key* r,
461 	struct regional* temp);
462 
463 /**
464  * See if two sets of tag lists (in the form of bitmap) have the same tag that
465  * has an action.  If so, '*tag' will be set to the found tag index, and the
466  * corresponding action will be returned in the form of local zone type.
467  * Otherwise the passed type (lzt) will be returned as the default action.
468  * Pointers except tagactions must not be NULL.
469  * @param taglist: 1st list of tags
470  * @param taglen: size of taglist in bytes
471  * @param taglist2: 2nd list of tags
472  * @param taglen2: size of taglist2 in bytes
473  * @param tagactions: local data actions for tags. May be NULL.
474  * @param tagactionssize: length of the tagactions.
475  * @param lzt: default action (local zone type) if no tag action is found.
476  * @param tag: see above.
477  * @param tagname: array of tag name strings (for debug output).
478  * @param num_tags: number of items in tagname array.
479  * @return found tag action or the default action.
480  */
481 enum localzone_type local_data_find_tag_action(const uint8_t* taglist,
482 	size_t taglen, const uint8_t* taglist2, size_t taglen2,
483 	const uint8_t* tagactions, size_t tagactionssize,
484 	enum localzone_type lzt, int* tag, char* const* tagname, int num_tags);
485 
486 /**
487  * Enter defaults to local zone.
488  * @param zones: to add defaults to
489  * @param cfg: containing list of zones to exclude from default set.
490  * @return 1 on success; 0 otherwise.
491  */
492 int local_zone_enter_defaults(struct local_zones* zones,
493 	struct config_file* cfg);
494 
495 /**
496   * Parses resource record string into wire format, also returning its field values.
497   * @param str: input resource record
498   * @param nm: domain name field
499   * @param type: record type field
500   * @param dclass: record class field
501   * @param ttl: ttl field
502   * @param rr: buffer for the parsed rr in wire format
503   * @param len: buffer length
504   * @param rdata: rdata field
505   * @param rdata_len: rdata field length
506   * @return 1 on success; 0 otherwise.
507   */
508 int rrstr_get_rr_content(const char* str, uint8_t** nm, uint16_t* type,
509 	uint16_t* dclass, time_t* ttl, uint8_t* rr, size_t len,
510 	uint8_t** rdata, size_t* rdata_len);
511 
512 /**
513   * Insert specified rdata into the specified resource record.
514   * @param region: allocator
515   * @param pd: data portion of the destination resource record
516   * @param rdata: source rdata
517   * @param rdata_len: source rdata length
518   * @param ttl: time to live
519   * @param rrstr: resource record in text form (for logging)
520   * @return 1 on success; 0 otherwise.
521   */
522 int rrset_insert_rr(struct regional* region, struct packed_rrset_data* pd,
523 	uint8_t* rdata, size_t rdata_len, time_t ttl, const char* rrstr);
524 
525 /**
526  * Remove RR from rrset that is created using localzone's rrset_insert_rr.
527  * @param pd: the RRset containing the RR to remove
528  * @param index: index of RR to remove
529  * @return: 1 on success; 0 otherwise.
530  */
531 int
532 local_rrset_remove_rr(struct packed_rrset_data* pd, size_t index);
533 
534 /**
535   * Valid response ip actions for the IP-response-driven-action feature;
536   * defined here instead of in the respip module to enable sharing of enum
537   * values with the localzone_type enum.
538   * Note that these values except 'none' are the same as localzone types of
539   * the 'same semantics'.  It's intentional as we use these values via
540   * access-control-tags, which can be shared for both response ip actions and
541   * local zones.
542   */
543 enum respip_action {
544 	/** no respip action */
545 	respip_none = local_zone_unset,
546 	/** don't answer */
547 	respip_deny = local_zone_deny,
548 	/** redirect as per provided data */
549 	respip_redirect = local_zone_redirect,
550         /** log query source and answer query */
551 	respip_inform = local_zone_inform,
552         /** log query source and don't answer query */
553 	respip_inform_deny = local_zone_inform_deny,
554         /** log query source and redirect */
555 	respip_inform_redirect = local_zone_inform_redirect,
556         /** resolve normally, even when there is response-ip data */
557 	respip_always_transparent = local_zone_always_transparent,
558         /** answer with 'refused' response */
559 	respip_always_refuse = local_zone_always_refuse,
560         /** answer with 'no such domain' response */
561 	respip_always_nxdomain = local_zone_always_nxdomain,
562         /** answer with nodata response */
563 	respip_always_nodata = local_zone_always_nodata,
564         /** answer with nodata response */
565 	respip_always_deny = local_zone_always_deny,
566 
567 	/* The rest of the values are only possible as
568 	 * access-control-tag-action */
569 
570 	/** serves response data (if any), else, drops queries. */
571 	respip_refuse = local_zone_refuse,
572 	/** serves response data, else, nodata answer. */
573 	respip_static = local_zone_static,
574 	/** gives response data (if any), else nodata answer. */
575 	respip_transparent = local_zone_transparent,
576 	/** gives response data (if any), else nodata answer. */
577 	respip_typetransparent = local_zone_typetransparent,
578 	/** type invalid */
579 	respip_invalid = local_zone_invalid,
580 };
581 
582 /**
583  * Get local data from local zone and encode answer.
584  * @param z: local zone to use
585  * @param env: module env
586  * @param qinfo: qinfo
587  * @param edns: edns data, for message encoding
588  * @param repinfo: reply info, for message encoding
589  * @param buf: commpoint buffer
590  * @param temp: scratchpad region
591  * @param labs: number of labels in qname
592  * @param ldp: where to store local data
593  * @param lz_type: type of local zone
594  * @param tag: matching tag index
595  * @param tag_datas: alc specific tag data list
596  * @param tag_datas_size: size of tag_datas
597  * @param tagname: list of names of tags, for logging purpose
598  * @param num_tags: number of tags
599  * @return 1 on success
600  */
601 int
602 local_data_answer(struct local_zone* z, struct module_env* env,
603 	struct query_info* qinfo, struct edns_data* edns,
604 	struct comm_reply* repinfo, sldns_buffer* buf,
605 	struct regional* temp, int labs, struct local_data** ldp,
606 	enum localzone_type lz_type, int tag, struct config_strlist** tag_datas,
607 	size_t tag_datas_size, char** tagname, int num_tags);
608 
609 /**
610  * Add RR to local zone.
611  * @param z: local zone to add RR to
612  * @param nm: dname of RR
613  * @param nmlen: length of nm
614  * @param nmlabs: number of labels of nm
615  * @param rrtype: RR type
616  * @param rrclass: RR class
617  * @param ttl: TTL of RR to add
618  * @param rdata: RDATA of RR to add
619  * @param rdata_len: length of rdata
620  * @param rrstr: RR in string format, for logging
621  * @return: 1 on success
622  */
623 int
624 local_zone_enter_rr(struct local_zone* z, uint8_t* nm, size_t nmlen,
625 	int nmlabs, uint16_t rrtype, uint16_t rrclass, time_t ttl,
626 	uint8_t* rdata, size_t rdata_len, const char* rrstr);
627 
628 /**
629  * Find a data node by exact name for a local zone
630  * @param z: local_zone containing data tree
631  * @param nm: name of local-data element to find
632  * @param nmlen: length of nm
633  * @param nmlabs: labs of nm
634  * @return local_data on exact match, NULL otherwise.
635  */
636 struct local_data*
637 local_zone_find_data(struct local_zone* z, uint8_t* nm, size_t nmlen, int nmlabs);
638 #endif /* SERVICES_LOCALZONE_H */
639