xref: /titanic_41/usr/src/cmd/cmd-inet/usr.lib/mdnsd/mDNSEmbeddedAPI.h (revision 4b22b9337f359bfd063322244f5336cc7c6ffcfa)
1 /* -*- Mode: C; tab-width: 4 -*-
2  *
3  * Copyright (c) 2002-2003 Apple Computer, Inc. All rights reserved.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *     http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16 
17 
18    NOTE:
19    If you're building an application that uses DNS Service Discovery
20    this is probably NOT the header file you're looking for.
21    In most cases you will want to use /usr/include/dns_sd.h instead.
22 
23    This header file defines the lowest level raw interface to mDNSCore,
24    which is appropriate *only* on tiny embedded systems where everything
25    runs in a single address space and memory is extremely constrained.
26    All the APIs here are malloc-free, which means that the caller is
27    responsible for passing in a pointer to the relevant storage that
28    will be used in the execution of that call, and (when called with
29    correct parameters) all the calls are guaranteed to succeed. There
30    is never a case where a call can suffer intermittent failures because
31    the implementation calls malloc() and sometimes malloc() returns NULL
32    because memory is so limited that no more is available.
33    This is primarily for devices that need to have precisely known fixed
34    memory requirements, with absolutely no uncertainty or run-time variation,
35    but that certainty comes at a cost of more difficult programming.
36 
37    For applications running on general-purpose desktop operating systems
38    (Mac OS, Linux, Solaris, Windows, etc.) the API you should use is
39    /usr/include/dns_sd.h, which defines the API by which multiple
40    independent client processes communicate their DNS Service Discovery
41    requests to a single "mdnsd" daemon running in the background.
42 
43    Even on platforms that don't run multiple independent processes in
44    multiple independent address spaces, you can still use the preferred
45    dns_sd.h APIs by linking in "dnssd_clientshim.c", which implements
46    the standard "dns_sd.h" API calls, allocates any required storage
47    using malloc(), and then calls through to the low-level malloc-free
48    mDNSCore routines defined here. This has the benefit that even though
49    you're running on a small embedded system with a single address space,
50    you can still use the exact same client C code as you'd use on a
51    general-purpose desktop system.
52 
53 
54     Change History (most recent first):
55 
56 $Log: mDNSEmbeddedAPI.h,v $
57 Revision 1.296.2.1  2006/08/29 06:24:22  cheshire
58 Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
59 
60 Revision 1.296  2006/06/29 05:28:01  cheshire
61 Added comment about mDNSlocal and mDNSexport
62 
63 Revision 1.295  2006/06/29 03:02:43  cheshire
64 <rdar://problem/4607042> mDNSResponder NXDOMAIN and CNAME support
65 
66 Revision 1.294  2006/06/28 06:50:08  cheshire
67 In future we may want to change definition of mDNSs32 from "signed long" to "signed int"
68 I doubt anyone is building mDNSResponder on systems where int is 16-bits,
69 but lets add a compile-time assertion to make sure.
70 
71 Revision 1.293  2006/06/12 18:00:43  cheshire
72 To make code a little more defensive, check _ILP64 before _LP64,
73 in case both are set by mistake on some platforms
74 
75 Revision 1.292  2006/03/19 17:00:57  cheshire
76 Define symbol MaxMsg instead of using hard-coded constant value '80'
77 
78 Revision 1.291  2006/03/19 02:00:07  cheshire
79 <rdar://problem/4073825> Improve logic for delaying packets after repeated interface transitions
80 
81 Revision 1.290  2006/03/08 22:42:23  cheshire
82 Fix spelling mistake: LocalReverseMapomain -> LocalReverseMapDomain
83 
84 Revision 1.289  2006/02/26 00:54:41  cheshire
85 Fixes to avoid code generation warning/error on FreeBSD 7
86 
87 Revision 1.288  2005/12/21 03:24:58  cheshire
88 <rdar://problem/4388858> Code changes required to compile on EFI
89 
90 Revision 1.287  2005/10/20 00:10:33  cheshire
91 <rdar://problem/4290265> Add check to avoid crashing NAT gateways that have buggy DNS relay code
92 
93 Revision 1.286  2005/09/24 01:09:40  cheshire
94 Fix comment typos
95 
96 Revision 1.285  2005/09/16 20:57:47  cheshire
97 Add macro mDNS_TimeNow_NoLock(m) to get properly adjusted time without also acquiring lock
98 
99 Revision 1.284  2005/07/29 18:04:22  ksekar
100 <rdar://problem/4137930> Hostname registration should register IPv6 AAAA record with DNS Update
101 
102 Revision 1.283  2005/05/13 20:45:09  ksekar
103 <rdar://problem/4074400> Rapid wide-area txt record updates don't work
104 
105 Revision 1.282  2005/03/16 00:42:32  ksekar
106 <rdar://problem/4012279> Long-lived queries not working on Windows
107 
108 Revision 1.281  2005/02/25 17:47:44  ksekar
109 <rdar://problem/4021868> SendServiceRegistration fails on wake from sleep
110 
111 Revision 1.280  2005/02/25 04:21:00  cheshire
112 <rdar://problem/4015377> mDNS -F returns the same domain multiple times with different casing
113 
114 Revision 1.279  2005/02/17 01:56:14  cheshire
115 Increase ifname field to 64 bytes
116 
117 Revision 1.278  2005/02/09 23:38:51  ksekar
118 <rdar://problem/3993508> Reregister hostname when DNS server changes but IP address does not
119 
120 Revision 1.277  2005/02/09 23:31:12  ksekar
121 <rdar://problem/3984374> NAT-PMP response callback should return a boolean indicating if the packet matched the request
122 
123 Revision 1.276  2005/02/01 19:33:29  ksekar
124 <rdar://problem/3985239> Keychain format too restrictive
125 
126 Revision 1.275  2005/01/27 22:57:55  cheshire
127 Fix compile errors on gcc4
128 
129 Revision 1.274  2005/01/19 21:01:54  ksekar
130 <rdar://problem/3955355> uDNS needs to support subtype registration and browsing
131 
132 Revision 1.273  2005/01/19 19:15:31  ksekar
133 Refinement to <rdar://problem/3954575> - Simplify mDNS_PurgeResultsForDomain logic and move into daemon layer
134 
135 Revision 1.272  2005/01/18 18:10:55  ksekar
136 <rdar://problem/3954575> Use 10.4 resolver API to get search domains
137 
138 Revision 1.271  2005/01/15 00:56:41  ksekar
139 <rdar://problem/3954575> Unicast services don't disappear when logging
140 out of VPN
141 
142 Revision 1.270  2005/01/14 18:34:22  ksekar
143 <rdar://problem/3954571> Services registered outside of firewall don't succeed after location change
144 
145 Revision 1.269  2005/01/11 22:50:52  ksekar
146 Fixed constant naming (was using kLLQ_DefLease for update leases)
147 
148 Revision 1.268  2004/12/22 22:25:47  ksekar
149 <rdar://problem/3734265> NATPMP: handle location changes
150 
151 Revision 1.267  2004/12/22 00:13:49  ksekar
152 <rdar://problem/3873993> Change version, port, and polling interval for LLQ
153 
154 Revision 1.266  2004/12/18 03:13:45  cheshire
155 <rdar://problem/3751638> kDNSServiceInterfaceIndexLocalOnly should return all local records
156 
157 Revision 1.265  2004/12/17 23:37:45  cheshire
158 <rdar://problem/3485365> Guard against repeating wireless dissociation/re-association
159 (and other repetitive configuration changes)
160 
161 Revision 1.264  2004/12/17 05:25:46  cheshire
162 <rdar://problem/3925163> Shorten DNS-SD queries to avoid NAT bugs
163 
164 Revision 1.263  2004/12/16 20:40:25  cheshire
165 Fix compile warnings
166 
167 Revision 1.262  2004/12/16 20:13:00  cheshire
168 <rdar://problem/3324626> Cache memory management improvements
169 
170 Revision 1.261  2004/12/14 21:21:20  ksekar
171 <rdar://problem/3825979> NAT-PMP: Update response format to contain "Seconds Since Boot"
172 
173 Revision 1.260  2004/12/12 23:51:42  ksekar
174 <rdar://problem/3845683> Wide-area registrations should fallback to using DHCP hostname as target
175 
176 Revision 1.259  2004/12/11 20:55:29  ksekar
177 <rdar://problem/3916479> Clean up registration state machines
178 
179 Revision 1.258  2004/12/10 20:48:32  cheshire
180 <rdar://problem/3705229> Need to pick final EDNS numbers for LLQ and GC
181 
182 Revision 1.257  2004/12/10 02:09:23  cheshire
183 <rdar://problem/3898376> Modify default TTLs
184 
185 Revision 1.256  2004/12/09 03:15:40  ksekar
186 <rdar://problem/3806610> use _legacy instead of _default to find "empty string" browse domains
187 
188 Revision 1.255  2004/12/07 22:48:37  cheshire
189 Tidying
190 
191 Revision 1.254  2004/12/07 21:26:04  ksekar
192 <rdar://problem/3908336> DNSServiceRegisterRecord() can crash on deregistration
193 
194 Revision 1.253  2004/12/07 20:42:33  cheshire
195 Add explicit context parameter to mDNS_RemoveRecordFromService()
196 
197 Revision 1.252  2004/12/07 03:02:12  ksekar
198 Fixed comments, grouped unicast-specific routines together
199 
200 Revision 1.251  2004/12/06 21:15:22  ksekar
201 <rdar://problem/3884386> mDNSResponder crashed in CheckServiceRegistrations
202 
203 Revision 1.250  2004/12/04 02:12:45  cheshire
204 <rdar://problem/3517236> mDNSResponder puts LargeCacheRecord on the stack
205 
206 Revision 1.249  2004/12/03 05:18:33  ksekar
207 <rdar://problem/3810596> mDNSResponder needs to return more specific TSIG errors
208 
209 Revision 1.248  2004/12/02 20:03:48  ksekar
210 <rdar://problem/3889647> Still publishes wide-area domains even after switching to a local subnet
211 
212 Revision 1.247  2004/12/01 20:57:19  ksekar
213 <rdar://problem/3873921> Wide Area Service Discovery must be split-DNS aware
214 
215 Revision 1.246  2004/11/29 23:26:32  cheshire
216 Added NonZeroTime() function, which usually returns the value given, with the exception
217 that if the value given is zero, it returns one instead. For timer values where zero is
218 used to mean "not set", this can be used to ensure that setting them to the result of an
219 interval computation (e.g. "now+interval") does not inadvertently result in a zero value.
220 
221 Revision 1.245  2004/11/25 01:28:09  cheshire
222 <rdar://problem/3557050> Need to implement random delay for 'QU' unicast replies (and set cache flush bit too)
223 
224 Revision 1.244  2004/11/24 22:00:59  cheshire
225 Move definition of mDNSAddressIsAllDNSLinkGroup() from mDNSMacOSX.c to mDNSEmbeddedAPI.h
226 
227 Revision 1.243  2004/11/23 22:43:53  cheshire
228 Tidy up code alignment
229 
230 Revision 1.242  2004/11/23 03:39:46  cheshire
231 Let interface name/index mapping capability live directly in JNISupport.c,
232 instead of having to call through to the daemon via IPC to get this information.
233 
234 Revision 1.241  2004/11/22 17:16:19  ksekar
235 <rdar://problem/3854298> Unicast services don't disappear when you disable all networking
236 
237 Revision 1.240  2004/11/19 02:32:43  ksekar
238 Wide-Area Security: Add LLQ-ID to events
239 
240 Revision 1.239  2004/11/15 20:09:23  ksekar
241 <rdar://problem/3719050> Wide Area support for Add/Remove record
242 
243 Revision 1.238  2004/11/12 03:16:48  rpantos
244 rdar://problem/3809541 Add mDNSPlatformGetInterfaceByName, mDNSPlatformGetInterfaceName
245 
246 Revision 1.237  2004/11/10 20:40:53  ksekar
247 <rdar://problem/3868216> LLQ mobility fragile on non-primary interface
248 
249 Revision 1.236  2004/11/01 20:36:11  ksekar
250 <rdar://problem/3802395> mDNSResponder should not receive Keychain Notifications
251 
252 Revision 1.235  2004/11/01 17:48:14  cheshire
253 Changed SOA serial number back to signed. RFC 1035 may describe it as "unsigned", but
254 it's wrong. The SOA serial is a modular counter, as explained in "DNS & BIND", page
255 137. Since C doesn't have a modular type, we used signed, C's closest approximation.
256 
257 Revision 1.234  2004/10/29 21:59:02  ksekar
258 SOA serial should be a unsigned integer, as per RFC 1035
259 
260 Revision 1.233  2004/10/28 03:24:41  cheshire
261 Rename m->CanReceiveUnicastOn as m->CanReceiveUnicastOn5353
262 
263 Revision 1.232  2004/10/26 06:20:23  cheshire
264 Add mDNSAddressIsValidNonZero() macro
265 
266 Revision 1.231  2004/10/26 06:11:41  cheshire
267 Add improved logging to aid in diagnosis of <rdar://problem/3842714> mDNSResponder crashed
268 
269 Revision 1.230  2004/10/26 03:52:02  cheshire
270 Update checkin comments
271 
272 Revision 1.229  2004/10/25 19:30:52  ksekar
273 <rdar://problem/3827956> Simplify dynamic host name structures
274 
275 Revision 1.228  2004/10/23 01:16:00  cheshire
276 <rdar://problem/3851677> uDNS operations not always reliable on multi-homed hosts
277 
278 Revision 1.227  2004/10/22 20:52:07  ksekar
279 <rdar://problem/3799260> Create NAT port mappings for Long Lived Queries
280 
281 Revision 1.226  2004/10/20 01:50:40  cheshire
282 <rdar://problem/3844991> Cannot resolve non-local registrations using the mach API
283 Implemented ForceMCast mode for AuthRecords as well as for Questions
284 
285 Revision 1.225  2004/10/19 21:33:17  cheshire
286 <rdar://problem/3844991> Cannot resolve non-local registrations using the mach API
287 Added flag 'kDNSServiceFlagsForceMulticast'. Passing through an interface id for a unicast name
288 doesn't force multicast unless you set this flag to indicate explicitly that this is what you want
289 
290 Revision 1.224  2004/10/16 00:16:59  cheshire
291 <rdar://problem/3770558> Replace IP TTL 255 check with local subnet source address check
292 
293 Revision 1.223  2004/10/15 23:00:17  ksekar
294 <rdar://problem/3799242> Need to update LLQs on location changes
295 
296 Revision 1.222  2004/10/12 02:49:20  ksekar
297 <rdar://problem/3831228> Clean up LLQ sleep/wake, error handling
298 
299 Revision 1.221  2004/10/10 06:57:15  cheshire
300 Change definition of "localdomain" to make code compile a little smaller
301 
302 Revision 1.220  2004/10/06 01:44:19  cheshire
303 <rdar://problem/3813936> Resolving too quickly sometimes returns stale TXT record
304 
305 Revision 1.219  2004/10/03 23:18:58  cheshire
306 Move address comparison macros from DNSCommon.h to mDNSEmbeddedAPI.h
307 
308 Revision 1.218  2004/10/03 23:14:12  cheshire
309 Add "mDNSEthAddr" type and "zeroEthAddr" constant
310 
311 Revision 1.217  2004/09/30 00:24:56  ksekar
312 <rdar://problem/3695802> Dynamically update default registration domains on config change
313 
314 Revision 1.216  2004/09/27 23:24:32  cheshire
315 Fix typo: SOA refresh interval is supposed to be unsigned
316 
317 Revision 1.215  2004/09/26 23:20:35  ksekar
318 <rdar://problem/3813108> Allow default registrations in multiple wide-area domains
319 
320 Revision 1.214  2004/09/25 02:41:39  cheshire
321 <rdar://problem/3637266> Deliver near-pending "remove" events before new "add" events
322 
323 Revision 1.213  2004/09/25 02:24:27  cheshire
324 Removed unused rr->UseCount
325 
326 Revision 1.212  2004/09/24 20:57:39  cheshire
327 <rdar://problem/3680902> Eliminate inappropriate casts that cause misaligned-address errors
328 
329 Revision 1.211  2004/09/24 20:33:22  cheshire
330 Remove unused DNSDigest_MD5 declaration
331 
332 Revision 1.210  2004/09/23 20:21:07  cheshire
333 <rdar://problem/3426876> Refine "immediate answer burst; restarting exponential backoff sequence" logic
334 Associate a unique sequence number with each received packet, and only increment the count of recent answer
335 packets if the packet sequence number for this answer record is not one we've already seen and counted.
336 
337 Revision 1.209  2004/09/23 20:14:39  cheshire
338 Rename "question->RecentAnswers" to "question->RecentAnswerPkts"
339 
340 Revision 1.208  2004/09/23 00:50:53  cheshire
341 <rdar://problem/3419452> Don't send a (DE) if a service is unregistered after wake from sleep
342 
343 Revision 1.207  2004/09/22 02:34:46  cheshire
344 Move definitions of default TTL times from mDNS.c to mDNSEmbeddedAPI.h
345 
346 Revision 1.206  2004/09/22 00:41:59  cheshire
347 Move tcp connection status codes into the legal range allocated for mDNS use
348 
349 Revision 1.205  2004/09/21 23:40:11  ksekar
350 <rdar://problem/3810349> mDNSResponder to return errors on NAT traversal failure
351 
352 Revision 1.204  2004/09/21 23:29:50  cheshire
353 <rdar://problem/3680045> DNSServiceResolve should delay sending packets
354 
355 Revision 1.203  2004/09/21 20:58:22  cheshire
356 Add ifname field to NetworkInterfaceInfo_struct
357 
358 Revision 1.202  2004/09/17 00:46:34  cheshire
359 mDNS_TimeNow should take const mDNS parameter
360 
361 Revision 1.201  2004/09/17 00:31:51  cheshire
362 For consistency with ipv6, renamed rdata field 'ip' to 'ipv4'
363 
364 Revision 1.200  2004/09/17 00:19:10  cheshire
365 For consistency with AllDNSLinkGroupv6, rename AllDNSLinkGroup to AllDNSLinkGroupv4
366 
367 Revision 1.199  2004/09/16 21:59:16  cheshire
368 For consistency with zerov6Addr, rename zeroIPAddr to zerov4Addr
369 
370 Revision 1.198  2004/09/16 21:36:36  cheshire
371 <rdar://problem/3803162> Fix unsafe use of mDNSPlatformTimeNow()
372 Changes to add necessary locking calls around unicast DNS operations
373 
374 Revision 1.197  2004/09/16 00:24:48  cheshire
375 <rdar://problem/3803162> Fix unsafe use of mDNSPlatformTimeNow()
376 
377 Revision 1.196  2004/09/14 23:42:35  cheshire
378 <rdar://problem/3801296> Need to seed random number generator from platform-layer data
379 
380 Revision 1.195  2004/09/14 23:27:46  cheshire
381 Fix compile errors
382 
383 Revision 1.194  2004/09/10 00:49:57  cheshire
384 <rdar://problem/3787644> Add error code kDNSServiceErr_Firewall, for future use
385 
386 Revision 1.193  2004/09/03 19:23:05  ksekar
387 <rdar://problem/3788460>: Need retransmission mechanism for wide-area service registrations
388 
389 Revision 1.192  2004/09/02 03:48:47  cheshire
390 <rdar://problem/3709039> Disable targeted unicast query support by default
391 1. New flag kDNSServiceFlagsAllowRemoteQuery to indicate we want to allow remote queries for this record
392 2. New field AllowRemoteQuery in AuthRecord structure
393 3. uds_daemon.c sets AllowRemoteQuery if kDNSServiceFlagsAllowRemoteQuery is set
394 4. mDNS.c only answers remote queries if AllowRemoteQuery is set
395 
396 Revision 1.191  2004/08/25 00:37:27  ksekar
397 <rdar://problem/3774635>: Cleanup DynDNS hostname registration code
398 
399 Revision 1.190  2004/08/18 17:35:41  ksekar
400 <rdar://problem/3651443>: Feature #9586: Need support for Legacy NAT gateways
401 
402 Revision 1.189  2004/08/14 03:22:41  cheshire
403 <rdar://problem/3762579> Dynamic DNS UI <-> mDNSResponder glue
404 Add GetUserSpecifiedDDNSName() routine
405 Convert ServiceRegDomain to domainname instead of C string
406 Replace mDNS_GenerateFQDN/mDNS_GenerateGlobalFQDN with mDNS_SetFQDNs
407 
408 Revision 1.188  2004/08/13 23:46:58  cheshire
409 "asyncronous" -> "asynchronous"
410 
411 Revision 1.187  2004/08/13 23:37:02  cheshire
412 Now that we do both uDNS and mDNS, global replace "uDNS_info.hostname" with
413 "uDNS_info.UnicastHostname" for clarity
414 
415 Revision 1.186  2004/08/13 23:25:00  cheshire
416 Now that we do both uDNS and mDNS, global replace "m->hostname" with
417 "m->MulticastHostname" for clarity
418 
419 Revision 1.185  2004/08/12 00:32:36  ksekar
420 <rdar://problem/3759567>: LLQ Refreshes never terminate if unanswered
421 
422 Revision 1.184  2004/08/11 17:09:31  cheshire
423 Add comment clarifying the applicability of these APIs
424 
425 Revision 1.183  2004/08/10 23:19:14  ksekar
426 <rdar://problem/3722542>: DNS Extension daemon for Wide Area Service Discovery
427 Moved routines/constants to allow extern access for garbage collection daemon
428 
429 Revision 1.182  2004/07/30 17:40:06  ksekar
430 <rdar://problem/3739115>: TXT Record updates not available for wide-area services
431 
432 Revision 1.181  2004/07/29 19:27:15  ksekar
433 NATPMP Support - minor fixes and cleanup
434 
435 Revision 1.180  2004/07/29 02:03:35  ksekar
436 Delete unused #define and structure field
437 
438 Revision 1.179  2004/07/26 22:49:30  ksekar
439 <rdar://problem/3651409>: Feature #9516: Need support for NATPMP in client
440 
441 Revision 1.178  2004/07/13 21:24:24  rpantos
442 Fix for <rdar://problem/3701120>.
443 
444 Revision 1.177  2004/06/05 00:04:26  cheshire
445 <rdar://problem/3668639>: wide-area domains should be returned in reg. domain enumeration
446 
447 Revision 1.176  2004/06/04 08:58:29  ksekar
448 <rdar://problem/3668624>: Keychain integration for secure dynamic update
449 
450 Revision 1.175  2004/06/04 00:15:06  cheshire
451 Move misplaced brackets
452 
453 Revision 1.174  2004/06/03 23:30:16  cheshire
454 Remove extraneous blank lines and white space
455 
456 Revision 1.173  2004/06/03 03:09:58  ksekar
457 <rdar://problem/3668626>: Garbage Collection for Dynamic Updates
458 
459 Revision 1.172  2004/06/01 23:46:50  ksekar
460 <rdar://problem/3675149>: DynDNS: dynamically look up LLQ/Update ports
461 
462 Revision 1.171  2004/05/28 23:42:37  ksekar
463 <rdar://problem/3258021>: Feature: DNS server->client notification on record changes (#7805)
464 
465 Revision 1.170  2004/05/18 23:51:25  cheshire
466 Tidy up all checkin comments to use consistent "<rdar://problem/xxxxxxx>" format for bug numbers
467 
468 Revision 1.169  2004/05/13 04:54:20  ksekar
469 Unified list copy/free code.  Added symetric list for
470 
471 Revision 1.168  2004/05/12 22:03:09  ksekar
472 Made GetSearchDomainList a true platform-layer call (declaration moved
473 from mDNSMacOSX.h to mDNSEmbeddedAPI.h), implemented to return "local"
474 only on non-OSX platforms.  Changed call to return a copy of the list
475 to avoid shared memory issues.  Added a routine to free the list.
476 
477 Revision 1.167  2004/04/22 04:07:01  cheshire
478 Fix from Bob Bradley: Don't try to do inline functions on compilers that don't support it
479 
480 Revision 1.166  2004/04/22 03:15:56  cheshire
481 Fix use of "struct __attribute__((__packed__))" so it only applies on GCC >= 2.9
482 
483 Revision 1.165  2004/04/22 03:05:28  cheshire
484 kDNSClass_ANY should be kDNSQClass_ANY
485 
486 Revision 1.164  2004/04/21 02:55:03  cheshire
487 Update comments describing 'InterfaceActive' field
488 
489 Revision 1.163  2004/04/21 02:49:11  cheshire
490 To reduce future confusion, renamed 'TxAndRx' to 'McastTxRx'
491 
492 Revision 1.162  2004/04/15 00:51:28  bradley
493 Minor tweaks for Windows and C++ builds. Added casts for signed/unsigned integers and 64-bit pointers.
494 Prefix some functions with mDNS to avoid conflicts. Disable benign warnings on Microsoft compilers.
495 
496 Revision 1.161  2004/04/14 23:09:28  ksekar
497 Support for TSIG signed dynamic updates.
498 
499 Revision 1.160  2004/04/09 17:40:26  cheshire
500 Remove unnecessary "Multicast" field -- it duplicates the semantics of the existing McastTxRx field
501 
502 Revision 1.159  2004/04/09 16:37:15  cheshire
503 Suggestion from Bob Bradley:
504 Move NumCacheRecordsForInterfaceID() to DNSCommon.c so it's available to all platform layers
505 
506 Revision 1.158  2004/04/02 19:38:33  cheshire
507 Update comment about typical RR TTLs
508 
509 Revision 1.157  2004/04/02 19:35:53  cheshire
510 Add clarifying comments about legal mDNSInterfaceID values
511 
512 Revision 1.156  2004/04/02 19:19:48  cheshire
513 Add code to do optional logging of multi-packet KA list time intervals
514 
515 Revision 1.155  2004/03/24 00:29:45  ksekar
516 Make it safe to call StopQuery in a unicast question callback
517 
518 Revision 1.154  2004/03/20 01:05:49  cheshire
519 Test __LP64__ and __ILP64__ to compile properly on a wider range of 64-bit architectures
520 
521 Revision 1.153  2004/03/13 01:57:33  ksekar
522 <rdar://problem/3192546>: DynDNS: Dynamic update of service records
523 
524 Revision 1.152  2004/03/09 02:27:16  cheshire
525 Remove erroneous underscore in 'packed_struct' (makes no difference now, but might in future)
526 
527 Revision 1.151  2004/03/02 03:21:56  cheshire
528 <rdar://problem/3549576> Properly support "_services._dns-sd._udp" meta-queries
529 
530 Revision 1.150  2004/02/21 02:06:24  cheshire
531 Can't use anonymous unions -- they're non-standard and don't work on all compilers
532 
533 Revision 1.149  2004/02/06 23:04:19  ksekar
534 Basic Dynamic Update support via mDNS_Register (dissabled via
535 UNICAST_REGISTRATION #define)
536 
537 Revision 1.148  2004/02/03 19:47:36  ksekar
538 Added an asynchronous state machine mechanism to uDNS.c, including
539 calls to find the parent zone for a domain name.  Changes include code
540 in repository previously dissabled via "#if 0 incomplete".  Codepath
541 is currently unused, and will be called to create update records, etc.
542 
543 Revision 1.147  2004/02/03 18:57:35  cheshire
544 Update comment for "IsLocalDomain()"
545 
546 Revision 1.146  2004/01/30 02:20:24  bradley
547 Map inline to __inline when building with Microsoft C compilers since they do not support C99 inline.
548 
549 Revision 1.145  2004/01/29 02:59:17  ksekar
550 Unicast DNS: Changed from a resource record oriented question/response
551 matching to packet based matching.  New callback architecture allows
552 collections of records in a response to be processed differently
553 depending on the nature of the request, and allows the same structure
554 to be used for internal and client-driven queries with different processing needs.
555 
556 Revision 1.144  2004/01/28 20:20:45  ksekar
557 Unified ActiveQueries and ActiveInternalQueries lists, using a flag to
558 demux them.  Check-in includes work-in-progress code, #ifdef'd out.
559 
560 Revision 1.143  2004/01/28 03:41:00  cheshire
561 <rdar://problem/3541946>: Need ability to do targeted queries as well as multicast queries
562 
563 Revision 1.142  2004/01/28 02:30:07  ksekar
564 Added default Search Domains to unicast browsing, controlled via
565 Networking sharing prefs pane.  Stopped sending unicast messages on
566 every interface.  Fixed unicast resolving via mach-port API.
567 
568 Revision 1.141  2004/01/27 20:15:22  cheshire
569 <rdar://problem/3541288>: Time to prune obsolete code for listening on port 53
570 
571 Revision 1.140  2004/01/24 23:37:08  cheshire
572 At Kiren's suggestion, made functions to convert mDNSOpaque16s to/from integer values
573 
574 Revision 1.139  2004/01/24 08:46:26  bradley
575 Added InterfaceID<->Index platform interfaces since they are now used by all platforms for the DNS-SD APIs.
576 
577 Revision 1.138  2004/01/24 04:59:15  cheshire
578 Fixes so that Posix/Linux, OS9, Windows, and VxWorks targets build again
579 
580 Revision 1.137  2004/01/24 03:40:56  cheshire
581 Move mDNSAddrIsDNSMulticast() from DNSCommon.h to mDNSEmbeddedAPI.h so clients can use it
582 
583 Revision 1.136  2004/01/24 03:38:27  cheshire
584 Fix minor syntactic error: Headers should use "extern" declarations, not "mDNSexport"
585 
586 Revision 1.135  2004/01/23 23:23:15  ksekar
587 Added TCP support for truncated unicast messages.
588 
589 Revision 1.134  2004/01/22 03:54:11  cheshire
590 Create special meta-interface 'mDNSInterface_ForceMCast' (-2),
591 which means "do this query via multicast, even if it's apparently a unicast domain"
592 
593 Revision 1.133  2004/01/22 03:48:41  cheshire
594 Make sure uDNS client doesn't accidentally use query ID zero
595 
596 Revision 1.132  2004/01/22 03:43:08  cheshire
597 Export constants like mDNSInterface_LocalOnly so that the client layers can use them
598 
599 Revision 1.131  2004/01/21 21:53:18  cheshire
600 <rdar://problem/3448144>: Don't try to receive unicast responses if we're not the first to bind to the UDP port
601 
602 Revision 1.130  2003/12/14 05:05:29  cheshire
603 Add comments explaining mDNS_Init_NoCache and mDNS_Init_ZeroCacheSize
604 
605 Revision 1.129  2003/12/13 03:05:27  ksekar
606 <rdar://problem/3192548>: DynDNS: Unicast query of service records
607 
608 Revision 1.128  2003/12/01 21:44:23  cheshire
609 Add mStatus_BadInterfaceErr = -65552 for consistency with dns_sd.h
610 
611 Revision 1.127  2003/12/01 18:26:37  cheshire
612 Also pack the OpaqueXX union types. Otherwise, on some systems, mDNSOpaque16 is four bytes!
613 
614 Revision 1.126  2003/12/01 18:23:48  cheshire
615 <rdar://problem/3464646>: Scalar size problem in mDNS code on some 64-bit architectures
616 
617 Revision 1.125  2003/11/22 00:18:27  cheshire
618 Add compile-time asserts to verify correct sizes of mDNSu32, mDNSOpaque16, etc.
619 
620 Revision 1.124  2003/11/20 22:59:54  cheshire
621 Changed runtime checks in mDNS.c to be compile-time checks in mDNSEmbeddedAPI.h
622 Thanks to Bob Bradley for suggesting the ingenious compiler trick to make this work.
623 
624 Revision 1.123  2003/11/20 22:53:01  cheshire
625 Add comment about MAX_ESCAPED_DOMAIN_LABEL
626 
627 Revision 1.122  2003/11/20 20:49:53  cheshire
628 Another fix from HP: Use packedstruct macro to ensure proper packing for on-the-wire packet structures
629 
630 Revision 1.121  2003/11/20 05:01:38  cheshire
631 Update comments; add explanation of Advertise/DontAdvertiseLocalAddresses
632 
633 Revision 1.120  2003/11/14 20:59:08  cheshire
634 Clients can't use AssignDomainName macro because mDNSPlatformMemCopy is defined in mDNSPlatformFunctions.h.
635 Best solution is just to combine mDNSEmbeddedAPI.h and mDNSPlatformFunctions.h into a single file.
636 
637 Revision 1.119  2003/11/14 19:47:52  cheshire
638 Define symbol MAX_ESCAPED_DOMAIN_NAME to indicate recommended buffer size for ConvertDomainNameToCString
639 
640 Revision 1.118  2003/11/14 19:18:34  cheshire
641 Move AssignDomainName macro to mDNSEmbeddedAPI.h to that client layers can use it too
642 
643 Revision 1.117  2003/11/08 23:32:24  cheshire
644 Gave name to anonymous struct, to avoid errors on certain compilers.
645 (Thanks to ramaprasad.kr@hp.com for reporting this.)
646 
647 Revision 1.116  2003/11/07 03:32:56  cheshire
648 <rdar://problem/3472153> mDNSResponder delivers answers in inconsistent order
649 This is the real fix. Checkin 1.312 was overly simplistic; Calling GetFreeCacheRR() can sometimes
650 purge records from the cache, causing tail pointer *rp to be stale on return. The correct fix is
651 to maintain a system-wide tail pointer for each cache slot, and then if neccesary GetFreeCacheRR()
652 can update this pointer, so that mDNSCoreReceiveResponse() appends records in the right place.
653 
654 Revision 1.115  2003/09/23 00:53:54  cheshire
655 NumFailedProbes should be unsigned
656 
657 Revision 1.114  2003/08/29 19:44:15  cheshire
658 <rdar://problem/3400967> Traffic reduction: Eliminate synchronized QUs when a new service appears
659 1. Use m->RandomQueryDelay to impose a random delay in the range 0-500ms on queries
660    that already have at least one unique answer in the cache
661 2. For these queries, go straight to QM, skipping QU
662 
663 Revision 1.113  2003/08/21 19:31:58  cheshire
664 Cosmetic: Swap order of fields
665 
666 Revision 1.112  2003/08/21 19:27:36  cheshire
667 <rdar://problem/3387878> Traffic reduction: No need to announce record for longer than TTL
668 
669 Revision 1.111  2003/08/21 02:21:50  cheshire
670 <rdar://problem/3386473> Efficiency: Reduce repeated queries
671 
672 Revision 1.110  2003/08/20 23:39:31  cheshire
673 <rdar://problem/3344098> Review syslog messages, and remove as appropriate
674 
675 Revision 1.109  2003/08/19 22:24:10  cheshire
676 Comment change
677 
678 Revision 1.108  2003/08/19 22:20:00  cheshire
679 <rdar://problem/3376721> Don't use IPv6 on interfaces that have a routable IPv4 address configured
680 More minor refinements
681 
682 Revision 1.107  2003/08/19 06:48:25  cheshire
683 <rdar://problem/3376552> Guard against excessive record updates
684 Each record starts with 10 UpdateCredits.
685 Every update consumes one UpdateCredit.
686 UpdateCredits are replenished at a rate of one one per minute, up to a maximum of 10.
687 As the number of UpdateCredits declines, the number of announcements is similarly scaled back.
688 When fewer than 5 UpdateCredits remain, the first announcement is also delayed by an increasing amount.
689 
690 Revision 1.106  2003/08/19 04:49:28  cheshire
691 <rdar://problem/3368159> Interaction between v4, v6 and dual-stack hosts not working quite right
692 1. A dual-stack host should only suppress its own query if it sees the same query from other hosts on BOTH IPv4 and IPv6.
693 2. When we see the first v4 (or first v6) member of a group, we re-trigger questions and probes on that interface.
694 3. When we see the last v4 (or v6) member of a group go away, we revalidate all the records received on that interface.
695 
696 Revision 1.105  2003/08/19 02:33:37  cheshire
697 Update comments
698 
699 Revision 1.104  2003/08/19 02:31:11  cheshire
700 <rdar://problem/3378386> mDNSResponder overenthusiastic with final expiration queries
701 Final expiration queries now only mark the question for sending on the particular interface
702 pertaining to the record that's expiring.
703 
704 Revision 1.103  2003/08/18 19:05:44  cheshire
705 <rdar://problem/3382423> UpdateRecord not working right
706 Added "newrdlength" field to hold new length of updated rdata
707 
708 Revision 1.102  2003/08/16 03:39:00  cheshire
709 <rdar://problem/3338440> InterfaceID -1 indicates "local only"
710 
711 Revision 1.101  2003/08/15 20:16:02  cheshire
712 <rdar://problem/3366590> mDNSResponder takes too much RPRVT
713 We want to avoid touching the rdata pages, so we don't page them in.
714 1. RDLength was stored with the rdata, which meant touching the page just to find the length.
715    Moved this from the RData to the ResourceRecord object.
716 2. To avoid unnecessarily touching the rdata just to compare it,
717    compute a hash of the rdata and store the hash in the ResourceRecord object.
718 
719 Revision 1.100  2003/08/14 19:29:04  cheshire
720 <rdar://problem/3378473> Include cache records in SIGINFO output
721 Moved declarations of DNSTypeName() and GetRRDisplayString to mDNSEmbeddedAPI.h so daemon.c can use them
722 
723 Revision 1.99  2003/08/14 02:17:05  cheshire
724 <rdar://problem/3375491> Split generic ResourceRecord type into two separate types: AuthRecord and CacheRecord
725 
726 Revision 1.98  2003/08/12 19:56:23  cheshire
727 Update to APSL 2.0
728 
729 Revision 1.97  2003/08/12 14:59:27  cheshire
730 <rdar://problem/3374490> Rate-limiting blocks some legitimate responses
731 When setting LastMCTime also record LastMCInterface. When checking LastMCTime to determine
732 whether to suppress the response, also check LastMCInterface to see if it matches.
733 
734 Revision 1.96  2003/08/12 13:57:04  cheshire
735 <rdar://problem/3323817> Improve cache performance
736 Changed the number of hash table slots from 37 to 499
737 
738 Revision 1.95  2003/08/09 00:55:02  cheshire
739 <rdar://problem/3366553> mDNSResponder is taking 20-30% of the CPU
740 Don't scan the whole cache after every packet.
741 
742 Revision 1.94  2003/08/09 00:35:29  cheshire
743 
744 Revision 1.93  2003/08/08 18:55:48  cheshire
745 <rdar://problem/3370365> Guard against time going backwards
746 
747 Revision 1.92  2003/08/08 18:36:04  cheshire
748 <rdar://problem/3344154> Only need to revalidate on interface removal on platforms that have the PhantomInterfaces bug
749 
750 Revision 1.91  2003/08/06 21:33:39  cheshire
751 Fix compiler warnings on PocketPC 2003 (Windows CE)
752 
753 Revision 1.90  2003/08/06 20:30:17  cheshire
754 Add structure definition for rdataMX (not currently used, but good to have it for completeness)
755 
756 Revision 1.89  2003/08/06 18:58:19  cheshire
757 Update comments
758 
759 Revision 1.88  2003/07/24 23:45:44  cheshire
760 To eliminate compiler warnings, changed definition of mDNSBool from
761 "unsigned char" to "int", since "int" is in fact truly the type that C uses
762 for the result of comparison operators (a<b) and logical operators (a||b)
763 
764 Revision 1.87  2003/07/22 23:57:20  cheshire
765 Move platform-layer function prototypes from mDNSEmbeddedAPI.h to mDNSPlatformFunctions.h where they belong
766 
767 Revision 1.86  2003/07/20 03:52:02  ksekar
768 <rdar://problem/3320722>: Feature: New DNS-SD APIs (#7875) (mDNSResponder component)
769 Added error type for incompatibility between daemon and client versions
770 
771 Revision 1.85  2003/07/19 03:23:13  cheshire
772 <rdar://problem/2986147> mDNSResponder needs to receive and cache larger records
773 
774 Revision 1.84  2003/07/18 23:52:12  cheshire
775 To improve consistency of field naming, global search-and-replace:
776 NextProbeTime    -> NextScheduledProbe
777 NextResponseTime -> NextScheduledResponse
778 
779 Revision 1.83  2003/07/18 00:29:59  cheshire
780 <rdar://problem/3268878> Remove mDNSResponder version from packet header and use HINFO record instead
781 
782 Revision 1.82  2003/07/17 17:35:04  cheshire
783 <rdar://problem/3325583> Rate-limit responses, to guard against packet flooding
784 
785 Revision 1.81  2003/07/16 05:01:36  cheshire
786 Add fields 'LargeAnswers' and 'ExpectUnicastResponse' in preparation for
787 <rdar://problem/3315761> Need to implement "unicast response" request, using top bit of qclass
788 
789 Revision 1.80  2003/07/15 01:55:12  cheshire
790 <rdar://problem/3315777> Need to implement service registration with subtypes
791 
792 Revision 1.79  2003/07/13 02:28:00  cheshire
793 <rdar://problem/3325166> SendResponses didn't all its responses
794 Delete all references to RRInterfaceActive -- it's now superfluous
795 
796 Revision 1.78  2003/07/13 01:47:53  cheshire
797 Fix one error and one warning in the Windows build
798 
799 Revision 1.77  2003/07/11 01:32:38  cheshire
800 Syntactic cleanup (no change to funcationality): Now that we only have one host name,
801 rename field "hostname1" to "hostname", and field "RR_A1" to "RR_A".
802 
803 Revision 1.76  2003/07/11 01:28:00  cheshire
804 <rdar://problem/3161289> No more local.arpa
805 
806 Revision 1.75  2003/07/02 21:19:45  cheshire
807 <rdar://problem/3313413> Update copyright notices, etc., in source code comments
808 
809 Revision 1.74  2003/07/02 02:41:23  cheshire
810 <rdar://problem/2986146> mDNSResponder needs to start with a smaller cache and then grow it as needed
811 
812 Revision 1.73  2003/06/10 04:24:39  cheshire
813 <rdar://problem/3283637> React when we observe other people query unsuccessfully for a record that's in our cache
814 Some additional refinements:
815 Don't try to do this for unicast-response queries
816 better tracking of Qs and KAs in multi-packet KA lists
817 
818 Revision 1.72  2003/06/10 01:46:27  cheshire
819 Add better comments explaining how these data structures are intended to be used from the client layer
820 
821 Revision 1.71  2003/06/07 06:45:05  cheshire
822 <rdar://problem/3283666> No need for multiple machines to all be sending the same queries
823 
824 Revision 1.70  2003/06/07 04:50:53  cheshire
825 <rdar://problem/3283637> React when we observe other people query unsuccessfully for a record that's in our cache
826 
827 Revision 1.69  2003/06/07 04:22:17  cheshire
828 Add MsgBuffer for error log and debug messages
829 
830 Revision 1.68  2003/06/07 01:46:38  cheshire
831 <rdar://problem/3283540> When query produces zero results, call mDNS_Reconfirm() on any antecedent records
832 
833 Revision 1.67  2003/06/07 01:22:14  cheshire
834 <rdar://problem/3283516> mDNSResponder needs an mDNS_Reconfirm() function
835 
836 Revision 1.66  2003/06/07 00:59:43  cheshire
837 <rdar://problem/3283454> Need some randomness to spread queries on the network
838 
839 Revision 1.65  2003/06/06 21:41:11  cheshire
840 For consistency, mDNS_StopQuery() should return an mStatus result, just like all the other mDNSCore routines
841 
842 Revision 1.64  2003/06/06 21:38:55  cheshire
843 Renamed 'NewData' as 'FreshData' (The data may not be new data, just a refresh of data that we
844 already had in our cache. This refreshes our TTL on the data, but the data itself stays the same.)
845 
846 Revision 1.63  2003/06/06 17:20:14  cheshire
847 For clarity, rename question fields name/rrtype/rrclass as qname/qtype/qclass
848 (Global search-and-replace; no functional change to code execution.)
849 
850 Revision 1.62  2003/06/04 01:25:33  cheshire
851 <rdar://problem/3274950> Cannot perform multi-packet known-answer suppression messages
852 Display time interval between first and subsequent queries
853 
854 Revision 1.61  2003/06/03 05:02:16  cheshire
855 <rdar://problem/3277080> Duplicate registrations not handled as efficiently as they should be
856 
857 Revision 1.60  2003/05/31 00:09:49  cheshire
858 <rdar://problem/3274862> Add ability to discover what services are on a network
859 
860 Revision 1.59  2003/05/29 06:11:35  cheshire
861 <rdar://problem/3272214>:	Report if there appear to be too many "Resolve" callbacks
862 
863 Revision 1.58  2003/05/29 05:48:06  cheshire
864 Minor fix for when generating printf warnings: mDNS_snprintf arguments are now 3,4
865 
866 Revision 1.57  2003/05/26 03:21:27  cheshire
867 Tidy up address structure naming:
868 mDNSIPAddr         => mDNSv4Addr (for consistency with mDNSv6Addr)
869 mDNSAddr.addr.ipv4 => mDNSAddr.ip.v4
870 mDNSAddr.addr.ipv6 => mDNSAddr.ip.v6
871 
872 Revision 1.56  2003/05/26 03:01:27  cheshire
873 <rdar://problem/3268904> sprintf/vsprintf-style functions are unsafe; use snprintf/vsnprintf instead
874 
875 Revision 1.55  2003/05/26 00:47:30  cheshire
876 Comment clarification
877 
878 Revision 1.54  2003/05/24 16:39:48  cheshire
879 <rdar://problem/3268631> SendResponses also needs to handle multihoming better
880 
881 Revision 1.53  2003/05/23 02:15:37  cheshire
882 Fixed misleading use of the term "duplicate suppression" where it should have
883 said "known answer suppression". (Duplicate answer suppression is something
884 different, and duplicate question suppression is yet another thing, so the use
885 of the completely vague term "duplicate suppression" was particularly bad.)
886 
887 Revision 1.52  2003/05/22 02:29:22  cheshire
888 <rdar://problem/2984918> SendQueries needs to handle multihoming better
889 Complete rewrite of SendQueries. Works much better now :-)
890 
891 Revision 1.51  2003/05/21 20:14:55  cheshire
892 Fix comments and warnings
893 
894 Revision 1.50  2003/05/14 07:08:36  cheshire
895 <rdar://problem/3159272> mDNSResponder should be smarter about reconfigurations
896 Previously, when there was any network configuration change, mDNSResponder
897 would tear down the entire list of active interfaces and start again.
898 That was very disruptive, and caused the entire cache to be flushed,
899 and caused lots of extra network traffic. Now it only removes interfaces
900 that have really gone, and only adds new ones that weren't there before.
901 
902 Revision 1.49  2003/05/07 01:49:36  cheshire
903 Remove "const" in ConstructServiceName prototype
904 
905 Revision 1.48  2003/05/07 00:18:44  cheshire
906 Fix typo: "kDNSQClass_Mask" should be "kDNSClass_Mask"
907 
908 Revision 1.47  2003/05/06 00:00:46  cheshire
909 <rdar://problem/3248914> Rationalize naming of domainname manipulation functions
910 
911 Revision 1.46  2003/04/30 20:39:09  cheshire
912 Add comment
913 
914 Revision 1.45  2003/04/29 00:40:50  cheshire
915 Fix compiler warnings
916 
917 Revision 1.44  2003/04/26 02:41:56  cheshire
918 <rdar://problem/3241281> Change timenow from a local variable to a structure member
919 
920 Revision 1.43  2003/04/25 01:45:56  cheshire
921 <rdar://problem/3240002> mDNS_RegisterNoSuchService needs to include a host name
922 
923 Revision 1.42  2003/04/15 20:58:31  jgraessl
924 
925 <rdar://problem/3229014> Added a hash to lookup records in the cache.
926 
927 Revision 1.41  2003/04/15 18:09:13  jgraessl
928 
929 <rdar://problem/3228892>
930 Reviewed by: Stuart Cheshire
931 Added code to keep track of when the next cache item will expire so we can
932 call TidyRRCache only when necessary.
933 
934 Revision 1.40  2003/03/29 01:55:19  cheshire
935 <rdar://problem/3212360> mDNSResponder sometimes suffers false self-conflicts when it sees its own packets
936 Solution: Major cleanup of packet timing and conflict handling rules
937 
938 Revision 1.39  2003/03/27 03:30:55  cheshire
939 <rdar://problem/3210018> Name conflicts not handled properly, resulting in memory corruption, and eventual crash
940 Problem was that HostNameCallback() was calling mDNS_DeregisterInterface(), which is not safe in a callback
941 Fixes:
942 1. Make mDNS_DeregisterInterface() safe to call from a callback
943 2. Make HostNameCallback() use mDNS_DeadvertiseInterface() instead
944    (it never really needed to deregister the interface at all)
945 
946 Revision 1.38  2003/03/15 04:40:36  cheshire
947 Change type called "mDNSOpaqueID" to the more descriptive name "mDNSInterfaceID"
948 
949 Revision 1.37  2003/03/14 21:34:11  cheshire
950 <rdar://problem/3176950> Can't setup and print to Lexmark PS printers via Airport Extreme
951 Increase size of cache rdata from 512 to 768
952 
953 Revision 1.36  2003/03/05 03:38:35  cheshire
954 <rdar://problem/3185731> Bogus error message in console: died or deallocated, but no record of client can be found!
955 Fixed by leaving client in list after conflict, until client explicitly deallocates
956 
957 Revision 1.35  2003/02/21 02:47:54  cheshire
958 <rdar://problem/3099194> mDNSResponder needs performance improvements
959 Several places in the code were calling CacheRRActive(), which searched the entire
960 question list every time, to see if this cache resource record answers any question.
961 Instead, we now have a field "CRActiveQuestion" in the resource record structure
962 
963 Revision 1.34  2003/02/21 01:54:08  cheshire
964 <rdar://problem/3099194> mDNSResponder needs performance improvements
965 Switched to using new "mDNS_Execute" model (see "Implementer Notes.txt")
966 
967 Revision 1.33  2003/02/20 06:48:32  cheshire
968 <rdar://problem/3169535> Xserve RAID needs to do interface-specific registrations
969 Reviewed by: Josh Graessley, Bob Bradley
970 
971 Revision 1.32  2003/01/31 03:35:59  cheshire
972 <rdar://problem/3147097> mDNSResponder sometimes fails to find the correct results
973 When there were *two* active questions in the list, they were incorrectly
974 finding *each other* and *both* being marked as duplicates of another question
975 
976 Revision 1.31  2003/01/29 02:46:37  cheshire
977 Fix for IPv6:
978 A physical interface is identified solely by its InterfaceID (not by IP and type).
979 On a given InterfaceID, mDNSCore may send both v4 and v6 multicasts.
980 In cases where the requested outbound protocol (v4 or v6) is not supported on
981 that InterfaceID, the platform support layer should simply discard that packet.
982 
983 Revision 1.30  2003/01/29 01:47:08  cheshire
984 Rename 'Active' to 'CRActive' or 'InterfaceActive' for improved clarity
985 
986 Revision 1.29  2003/01/28 05:23:43  cheshire
987 <rdar://problem/3147097> mDNSResponder sometimes fails to find the correct results
988 Add 'Active' flag for interfaces
989 
990 Revision 1.28  2003/01/28 01:35:56  cheshire
991 Revise comment about ThisQInterval to reflect new semantics
992 
993 Revision 1.27  2003/01/13 23:49:42  jgraessl
994 Merged changes for the following fixes in to top of tree:
995 <rdar://problem/3086540>  computer name changes not handled properly
996 <rdar://problem/3124348>  service name changes are not properly handled
997 <rdar://problem/3124352>  announcements sent in pairs, failing chattiness test
998 
999 Revision 1.26  2002/12/23 22:13:28  jgraessl
1000 
1001 Reviewed by: Stuart Cheshire
1002 Initial IPv6 support for mDNSResponder.
1003 
1004 Revision 1.25  2002/09/21 20:44:49  zarzycki
1005 Added APSL info
1006 
1007 Revision 1.24  2002/09/19 23:47:35  cheshire
1008 Added mDNS_RegisterNoSuchService() function for assertion of non-existence
1009 of a particular named service
1010 
1011 Revision 1.23  2002/09/19 21:25:34  cheshire
1012 mDNS_snprintf() doesn't need to be in a separate file
1013 
1014 Revision 1.22  2002/09/19 04:20:43  cheshire
1015 Remove high-ascii characters that confuse some systems
1016 
1017 Revision 1.21  2002/09/17 01:06:35  cheshire
1018 Change mDNS_AdvertiseLocalAddresses to be a parameter to mDNS_Init()
1019 
1020 Revision 1.20  2002/09/16 18:41:41  cheshire
1021 Merge in license terms from Quinn's copy, in preparation for Darwin release
1022 
1023 */
1024 
1025 #pragma ident	"%Z%%M%	%I%	%E% SMI"
1026 
1027 #ifndef __mDNSClientAPI_h
1028 #define __mDNSClientAPI_h
1029 
1030 #if defined(EFI32) || defined(EFI64)
1031 // EFI doesn't have stdarg.h
1032 #include "Tiano.h"
1033 #define va_list			VA_LIST
1034 #define va_start(a, b)	VA_START(a, b)
1035 #define va_end(a)		VA_END(a)
1036 #define va_arg(a, b)	VA_ARG(a, b)
1037 #else
1038 #include <stdarg.h>		// stdarg.h is required for for va_list support for the mDNS_vsnprintf declaration
1039 #endif
1040 
1041 #include "mDNSDebug.h"
1042 
1043 #ifdef __cplusplus
1044 	extern "C" {
1045 #endif
1046 
1047 // ***************************************************************************
1048 // Function scope indicators
1049 
1050 // If you see "mDNSlocal" before a function name in a C file, it means the function is not callable outside this file
1051 #ifndef mDNSlocal
1052 #define mDNSlocal static
1053 #endif
1054 // If you see "mDNSexport" before a symbol in a C file, it means the symbol is exported for use by clients
1055 // For every "mDNSexport" in a C file, there needs to be a corresponding "extern" declaration in some header file
1056 // (When a C file #includes a header file, the "extern" declarations tell the compiler:
1057 // "This symbol exists -- but not necessarily in this C file.")
1058 #ifndef mDNSexport
1059 #define mDNSexport
1060 #endif
1061 
1062 // Explanation: These local/export markers are a little habit of mine for signaling the programmers' intentions.
1063 // When "mDNSlocal" is just a synonym for "static", and "mDNSexport" is a complete no-op, you could be
1064 // forgiven for asking what purpose they serve. The idea is that if you see "mDNSexport" in front of a
1065 // function definition it means the programmer intended it to be exported and callable from other files
1066 // in the project. If you see "mDNSlocal" in front of a function definition it means the programmer
1067 // intended it to be private to that file. If you see neither in front of a function definition it
1068 // means the programmer forgot (so you should work out which it is supposed to be, and fix it).
1069 // Using "mDNSlocal" instead of "static" makes it easier to do a textual searches for one or the other.
1070 // For example you can do a search for "static" to find if any functions declare any local variables as "static"
1071 // (generally a bad idea unless it's also "const", because static storage usually risks being non-thread-safe)
1072 // without the results being cluttered with hundreds of matches for functions declared static.
1073 // - Stuart Cheshire
1074 
1075 // ***************************************************************************
1076 // Structure packing macro
1077 
1078 // If we're not using GNUC, it's not fatal.
1079 // Most compilers naturally pack the on-the-wire structures correctly anyway, so a plain "struct" is usually fine.
1080 // In the event that structures are not packed correctly, mDNS_Init() will detect this and report an error, so the
1081 // developer will know what's wrong, and can investigate what needs to be done on that compiler to provide proper packing.
1082 #ifndef packedstruct
1083  #if ((__GNUC__ > 2) || ((__GNUC__ == 2) && (__GNUC_MINOR__ >= 9)))
1084   #define packedstruct struct __attribute__((__packed__))
1085   #define packedunion  union  __attribute__((__packed__))
1086  #else
1087   #define packedstruct struct
1088   #define packedunion  union
1089  #endif
1090 #endif
1091 
1092 // ***************************************************************************
1093 #if 0
1094 #pragma mark - DNS Resource Record class and type constants
1095 #endif
1096 
1097 typedef enum							// From RFC 1035
1098 	{
1099 	kDNSClass_IN               = 1,		// Internet
1100 	kDNSClass_CS               = 2,		// CSNET
1101 	kDNSClass_CH               = 3,		// CHAOS
1102 	kDNSClass_HS               = 4,		// Hesiod
1103 	kDNSClass_NONE             = 254,	// Used in DNS UPDATE [RFC 2136]
1104 
1105 	kDNSClass_Mask             = 0x7FFF,// Multicast DNS uses the bottom 15 bits to identify the record class...
1106 	kDNSClass_UniqueRRSet      = 0x8000,// ... and the top bit indicates that all other cached records are now invalid
1107 
1108 	kDNSQClass_ANY             = 255,	// Not a DNS class, but a DNS query class, meaning "all classes"
1109 	kDNSQClass_UnicastResponse = 0x8000	// Top bit set in a question means "unicast response acceptable"
1110 	} DNS_ClassValues;
1111 
1112 typedef enum				// From RFC 1035
1113 	{
1114 	kDNSType_A = 1,			//  1 Address
1115 	kDNSType_NS,			//  2 Name Server
1116 	kDNSType_MD,			//  3 Mail Destination
1117 	kDNSType_MF,			//  4 Mail Forwarder
1118 	kDNSType_CNAME,			//  5 Canonical Name
1119 	kDNSType_SOA,			//  6 Start of Authority
1120 	kDNSType_MB,			//  7 Mailbox
1121 	kDNSType_MG,			//  8 Mail Group
1122 	kDNSType_MR,			//  9 Mail Rename
1123 	kDNSType_NULL,			// 10 NULL RR
1124 	kDNSType_WKS,			// 11 Well-known-service
1125 	kDNSType_PTR,			// 12 Domain name pointer
1126 	kDNSType_HINFO,			// 13 Host information
1127 	kDNSType_MINFO,			// 14 Mailbox information
1128 	kDNSType_MX,			// 15 Mail Exchanger
1129 	kDNSType_TXT,			// 16 Arbitrary text string
1130 
1131 	kDNSType_AAAA = 28,		// 28 IPv6 address
1132 	kDNSType_SRV  = 33,		// 33 Service record
1133 	kDNSType_OPT  = 41,     // EDNS0 OPT record
1134 	kDNSType_TSIG = 250,    // 250 Transaction Signature
1135 
1136 	kDNSQType_ANY = 255		// Not a DNS type, but a DNS query type, meaning "all types"
1137 	} DNS_TypeValues;
1138 
1139 // ***************************************************************************
1140 #if 0
1141 #pragma mark - Simple types
1142 #endif
1143 
1144 // mDNS defines its own names for these common types to simplify portability across
1145 // multiple platforms that may each have their own (different) names for these types.
1146 typedef          int   mDNSBool;
1147 typedef   signed char  mDNSs8;
1148 typedef unsigned char  mDNSu8;
1149 typedef   signed short mDNSs16;
1150 typedef unsigned short mDNSu16;
1151 
1152 // <http://gcc.gnu.org/onlinedocs/gcc-3.3.3/cpp/Common-Predefined-Macros.html> says
1153 //   __LP64__ _LP64
1154 //   These macros are defined, with value 1, if (and only if) the compilation is
1155 //   for a target where long int and pointer both use 64-bits and int uses 32-bit.
1156 // <http://www.intel.com/software/products/compilers/clin/docs/ug/lin1077.htm> says
1157 //   Macro Name __LP64__ Value 1
1158 // A quick Google search for "defined(__LP64__)" OR "#ifdef __LP64__" gives 2590 hits and
1159 // a search for "#if __LP64__" gives only 12, so I think we'll go with the majority and use defined()
1160 #if defined(_ILP64) || defined(__ILP64__)
1161 typedef   signed int32 mDNSs32;
1162 typedef unsigned int32 mDNSu32;
1163 #elif defined(_LP64) || defined(__LP64__)
1164 typedef   signed int   mDNSs32;
1165 typedef unsigned int   mDNSu32;
1166 #else
1167 typedef   signed long  mDNSs32;
1168 typedef unsigned long  mDNSu32;
1169 //typedef   signed int mDNSs32;
1170 //typedef unsigned int mDNSu32;
1171 #endif
1172 
1173 // To enforce useful type checking, we make mDNSInterfaceID be a pointer to a dummy struct
1174 // This way, mDNSInterfaceIDs can be assigned, and compared with each other, but not with other types
1175 // Declaring the type to be the typical generic "void *" would lack this type checking
1176 typedef struct mDNSInterfaceID_dummystruct { void *dummy; } *mDNSInterfaceID;
1177 
1178 // These types are for opaque two- and four-byte identifiers.
1179 // The "NotAnInteger" fields of the unions allow the value to be conveniently passed around in a
1180 // register for the sake of efficiency, and compared for equality or inequality, but don't forget --
1181 // just because it is in a register doesn't mean it is an integer. Operations like greater than,
1182 // less than, add, multiply, increment, decrement, etc., are undefined for opaque identifiers,
1183 // and if you make the mistake of trying to do those using the NotAnInteger field, then you'll
1184 // find you get code that doesn't work consistently on big-endian and little-endian machines.
1185 typedef packedunion { mDNSu8 b[ 2]; mDNSu16 NotAnInteger; } mDNSOpaque16;
1186 typedef packedunion { mDNSu8 b[ 4]; mDNSu32 NotAnInteger; } mDNSOpaque32;
1187 typedef packedunion { mDNSu8 b[ 6]; mDNSu16 w[3]; mDNSu32 l[1]; } mDNSOpaque48;
1188 typedef packedunion { mDNSu8 b[16]; mDNSu16 w[8]; mDNSu32 l[4]; } mDNSOpaque128;
1189 
1190 typedef mDNSOpaque16  mDNSIPPort;		// An IP port is a two-byte opaque identifier (not an integer)
1191 typedef mDNSOpaque32  mDNSv4Addr;		// An IP address is a four-byte opaque identifier (not an integer)
1192 typedef mDNSOpaque128 mDNSv6Addr;		// An IPv6 address is a 16-byte opaque identifier (not an integer)
1193 typedef mDNSOpaque48  mDNSEthAddr;		// An Ethernet address is a six-byte opaque identifier (not an integer)
1194 
1195 enum
1196 	{
1197 	mDNSAddrType_None    = 0,
1198 	mDNSAddrType_IPv4    = 4,
1199 	mDNSAddrType_IPv6    = 6,
1200 	mDNSAddrType_Unknown = ~0	// Special marker value used in known answer list recording
1201 	};
1202 
1203 typedef struct
1204 	{
1205 	mDNSs32 type;
1206 	union { mDNSv6Addr v6; mDNSv4Addr v4; } ip;
1207 	} mDNSAddr;
1208 
1209 enum { mDNSfalse = 0, mDNStrue = 1 };
1210 
1211 #define mDNSNULL 0L
1212 
1213 enum
1214 	{
1215 	mStatus_Waiting           = 1,
1216 	mStatus_NoError           = 0,
1217 
1218 	// mDNS return values are in the range FFFE FF00 (-65792) to FFFE FFFF (-65537)
1219 	// The top end of the range (FFFE FFFF) is used for error codes;
1220 	// the bottom end of the range (FFFE FF00) is used for non-error values;
1221 
1222 	// Error codes:
1223 	mStatus_UnknownErr        = -65537,		// First value: 0xFFFE FFFF
1224 	mStatus_NoSuchNameErr     = -65538,
1225 	mStatus_NoMemoryErr       = -65539,
1226 	mStatus_BadParamErr       = -65540,
1227 	mStatus_BadReferenceErr   = -65541,
1228 	mStatus_BadStateErr       = -65542,
1229 	mStatus_BadFlagsErr       = -65543,
1230 	mStatus_UnsupportedErr    = -65544,
1231 	mStatus_NotInitializedErr = -65545,
1232 	mStatus_NoCache           = -65546,
1233 	mStatus_AlreadyRegistered = -65547,
1234 	mStatus_NameConflict      = -65548,
1235 	mStatus_Invalid           = -65549,
1236 	mStatus_Firewall          = -65550,
1237 	mStatus_Incompatible      = -65551,
1238 	mStatus_BadInterfaceErr   = -65552,
1239 	mStatus_Refused           = -65553,
1240 	mStatus_NoSuchRecord      = -65554,
1241 	mStatus_NoAuth            = -65555,
1242 	mStatus_NoSuchKey         = -65556,
1243 	mStatus_NATTraversal      = -65557,
1244 	mStatus_DoubleNAT         = -65558,
1245 	mStatus_BadTime           = -65559,
1246 	mStatus_BadSig            = -65560,     // while we define this per RFC 2845, BIND 9 returns Refused for bad/missing signatures
1247 	mStatus_BadKey            = -65561,
1248 	mStatus_TransientErr      = -65562,     // transient failures, e.g. sending packets shortly after a network transition or wake from sleep
1249 	// -65563 to -65786 currently unused; available for allocation
1250 
1251 	// tcp connection status
1252 	mStatus_ConnPending       = -65787,
1253 	mStatus_ConnFailed        = -65788,
1254 	mStatus_ConnEstablished   = -65789,
1255 
1256 	// Non-error values:
1257 	mStatus_GrowCache         = -65790,
1258 	mStatus_ConfigChanged     = -65791,
1259 	mStatus_MemFree           = -65792		// Last value: 0xFFFE FF00
1260 
1261 	// mStatus_MemFree is the last legal mDNS error code, at the end of the range allocated for mDNS
1262 	};
1263 
1264 typedef mDNSs32 mStatus;
1265 
1266 // RFC 1034/1035 specify that a domain label consists of a length byte plus up to 63 characters
1267 #define MAX_DOMAIN_LABEL 63
1268 typedef struct { mDNSu8 c[ 64]; } domainlabel;		// One label: length byte and up to 63 characters
1269 
1270 // RFC 1034/1035 specify that a domain name, including length bytes, data bytes, and terminating zero, may be up to 255 bytes long
1271 #define MAX_DOMAIN_NAME 255
1272 typedef struct { mDNSu8 c[256]; } domainname;		// Up to 255 bytes of length-prefixed domainlabels
1273 
1274 typedef struct { mDNSu8 c[256]; } UTF8str255;		// Null-terminated C string
1275 
1276 // The longest legal textual form of a DNS name is 1005 bytes, including the C-string terminating NULL at the end.
1277 // Explanation:
1278 // When a native domainname object is converted to printable textual form using ConvertDomainNameToCString(),
1279 // non-printing characters are represented in the conventional DNS way, as '\ddd', where ddd is a three-digit decimal number.
1280 // The longest legal domain name is 255 bytes, in the form of four labels as shown below:
1281 // Length byte, 63 data bytes, length byte, 63 data bytes, length byte, 63 data bytes, length byte, 61 data bytes, zero byte.
1282 // Each label is encoded textually as characters followed by a trailing dot.
1283 // If every character has to be represented as a four-byte escape sequence, then this makes the maximum textual form four labels
1284 // plus the C-string terminating NULL as shown below:
1285 // 63*4+1 + 63*4+1 + 63*4+1 + 61*4+1 + 1 = 1005.
1286 // Note that MAX_ESCAPED_DOMAIN_LABEL is not normally used: If you're only decoding a single label, escaping is usually not required.
1287 // It is for domain names, where dots are used as label separators, that proper escaping is vital.
1288 #define MAX_ESCAPED_DOMAIN_LABEL 254
1289 #define MAX_ESCAPED_DOMAIN_NAME 1005
1290 
1291 // Most records have a TTL of 75 minutes, so that their 80% cache-renewal query occurs once per hour.
1292 // For records containing a hostname (in the name on the left, or in the rdata on the right),
1293 // like A, AAAA, reverse-mapping PTR, and SRV, we use a two-minute TTL by default, because we don't want
1294 // them to hang around for too long in the cache if the host in question crashes or otherwise goes away.
1295 // Wide-area service discovery records have a very short TTL to avoid poluting intermediate caches with
1296 // dynamic records.  When discovered via Long Lived Queries (with change notifications), resource record
1297 // TTLs can be safely ignored.
1298 
1299 #define kStandardTTL (3600UL * 100 / 80)
1300 #define kHostNameTTL 120UL
1301 #define kWideAreaTTL 3
1302 
1303 #define DefaultTTLforRRType(X) (((X) == kDNSType_A || (X) == kDNSType_AAAA || (X) == kDNSType_SRV) ? kHostNameTTL : kStandardTTL)
1304 
1305 // ***************************************************************************
1306 #if 0
1307 #pragma mark - DNS Message structures
1308 #endif
1309 
1310 #define mDNS_numZones   numQuestions
1311 #define mDNS_numPrereqs numAnswers
1312 #define mDNS_numUpdates numAuthorities
1313 
1314 typedef packedstruct
1315 	{
1316 	mDNSOpaque16 id;
1317 	mDNSOpaque16 flags;
1318 	mDNSu16 numQuestions;
1319 	mDNSu16 numAnswers;
1320 	mDNSu16 numAuthorities;
1321 	mDNSu16 numAdditionals;
1322 	} DNSMessageHeader;
1323 
1324 // We can send and receive packets up to 9000 bytes (Ethernet Jumbo Frame size, if that ever becomes widely used)
1325 // However, in the normal case we try to limit packets to 1500 bytes so that we don't get IP fragmentation on standard Ethernet
1326 // 40 (IPv6 header) + 8 (UDP header) + 12 (DNS message header) + 1440 (DNS message body) = 1500 total
1327 #define AbsoluteMaxDNSMessageData 8940
1328 #define NormalMaxDNSMessageData 1440
1329 typedef packedstruct
1330 	{
1331 	DNSMessageHeader h;						// Note: Size 12 bytes
1332 	mDNSu8 data[AbsoluteMaxDNSMessageData];	// 40 (IPv6) + 8 (UDP) + 12 (DNS header) + 8940 (data) = 9000
1333 	} DNSMessage;
1334 
1335 // ***************************************************************************
1336 #if 0
1337 #pragma mark - Resource Record structures
1338 #endif
1339 
1340 // Authoritative Resource Records:
1341 // There are four basic types: Shared, Advisory, Unique, Known Unique
1342 
1343 // * Shared Resource Records do not have to be unique
1344 // -- Shared Resource Records are used for DNS-SD service PTRs
1345 // -- It is okay for several hosts to have RRs with the same name but different RDATA
1346 // -- We use a random delay on responses to reduce collisions when all the hosts respond to the same query
1347 // -- These RRs typically have moderately high TTLs (e.g. one hour)
1348 // -- These records are announced on startup and topology changes for the benefit of passive listeners
1349 // -- These records send a goodbye packet when deregistering
1350 //
1351 // * Advisory Resource Records are like Shared Resource Records, except they don't send a goodbye packet
1352 //
1353 // * Unique Resource Records should be unique among hosts within any given mDNS scope
1354 // -- The majority of Resource Records are of this type
1355 // -- If two entities on the network have RRs with the same name but different RDATA, this is a conflict
1356 // -- Responses may be sent immediately, because only one host should be responding to any particular query
1357 // -- These RRs typically have low TTLs (e.g. a few minutes)
1358 // -- On startup and after topology changes, a host issues queries to verify uniqueness
1359 
1360 // * Known Unique Resource Records are treated like Unique Resource Records, except that mDNS does
1361 // not have to verify their uniqueness because this is already known by other means (e.g. the RR name
1362 // is derived from the host's IP or Ethernet address, which is already known to be a unique identifier).
1363 
1364 // Summary of properties of different record types:
1365 // Probe?    Does this record type send probes before announcing?
1366 // Conflict? Does this record type react if we observe an apparent conflict?
1367 // Goodbye?  Does this record type send a goodbye packet on departure?
1368 //
1369 //               Probe? Conflict? Goodbye? Notes
1370 // Unregistered                            Should not appear in any list (sanity check value)
1371 // Shared         No      No       Yes     e.g. Service PTR record
1372 // Deregistering  No      No       Yes     Shared record about to announce its departure and leave the list
1373 // Advisory       No      No       No
1374 // Unique         Yes     Yes      No      Record intended to be unique -- will probe to verify
1375 // Verified       Yes     Yes      No      Record has completed probing, and is verified unique
1376 // KnownUnique    No      Yes      No      Record is assumed by other means to be unique
1377 
1378 // Valid lifecycle of a record:
1379 // Unregistered ->                   Shared      -> Deregistering -(goodbye)-> Unregistered
1380 // Unregistered ->                   Advisory                               -> Unregistered
1381 // Unregistered -> Unique -(probe)-> Verified                               -> Unregistered
1382 // Unregistered ->                   KnownUnique                            -> Unregistered
1383 
1384 // Each Authoritative kDNSRecordType has only one bit set. This makes it easy to quickly see if a record
1385 // is one of a particular set of types simply by performing the appropriate bitwise masking operation.
1386 
1387 // Cache Resource Records (received from the network):
1388 // There are four basic types: Answer, Unique Answer, Additional, Unique Additional
1389 // Bit 7 (the top bit) of kDNSRecordType is always set for Cache Resource Records; always clear for Authoritative Resource Records
1390 // Bit 6 (value 0x40) is set for answer records; clear for additional records
1391 // Bit 5 (value 0x20) is set for records received with the kDNSClass_UniqueRRSet
1392 
1393 enum
1394 	{
1395 	kDNSRecordTypeUnregistered     = 0x00,	// Not currently in any list
1396 	kDNSRecordTypeDeregistering    = 0x01,	// Shared record about to announce its departure and leave the list
1397 
1398 	kDNSRecordTypeUnique           = 0x02,	// Will become a kDNSRecordTypeVerified when probing is complete
1399 
1400 	kDNSRecordTypeAdvisory         = 0x04,	// Like Shared, but no goodbye packet
1401 	kDNSRecordTypeShared           = 0x08,	// Shared means record name does not have to be unique -- use random delay on responses
1402 
1403 	kDNSRecordTypeVerified         = 0x10,	// Unique means mDNS should check that name is unique (and then send immediate responses)
1404 	kDNSRecordTypeKnownUnique      = 0x20,	// Known Unique means mDNS can assume name is unique without checking
1405 	                                        // For Dynamic Update records, Known Unique means the record must already exist on the server.
1406 	kDNSRecordTypeUniqueMask       = (kDNSRecordTypeUnique | kDNSRecordTypeVerified | kDNSRecordTypeKnownUnique),
1407 	kDNSRecordTypeActiveMask       = (kDNSRecordTypeAdvisory | kDNSRecordTypeShared | kDNSRecordTypeVerified | kDNSRecordTypeKnownUnique),
1408 
1409 	kDNSRecordTypePacketAdd        = 0x80,	// Received in the Additional  Section of a DNS Response
1410 	kDNSRecordTypePacketAddUnique  = 0x90,	// Received in the Additional  Section of a DNS Response with kDNSClass_UniqueRRSet set
1411 	kDNSRecordTypePacketAuth       = 0xA0,	// Received in the Authorities Section of a DNS Response
1412 	kDNSRecordTypePacketAuthUnique = 0xB0,	// Received in the Authorities Section of a DNS Response with kDNSClass_UniqueRRSet set
1413 	kDNSRecordTypePacketAns        = 0xC0,	// Received in the Answer      Section of a DNS Response
1414 	kDNSRecordTypePacketAnsUnique  = 0xD0,	// Received in the Answer      Section of a DNS Response with kDNSClass_UniqueRRSet set
1415 
1416 	kDNSRecordTypePacketAnsMask    = 0x40,	// True for PacketAns and    PacketAnsUnique
1417 	kDNSRecordTypePacketUniqueMask = 0x10	// True for PacketAddUnique, PacketAnsUnique, PacketAuthUnique
1418 	};
1419 
1420 typedef packedstruct { mDNSu16 priority; mDNSu16 weight; mDNSIPPort port; domainname target;   } rdataSRV;
1421 typedef packedstruct { mDNSu16 preference;                                domainname exchange; } rdataMX;
1422 typedef packedstruct
1423 	{
1424 	domainname mname;
1425 	domainname rname;
1426 	mDNSs32 serial;		// Modular counter; increases when zone changes
1427 	mDNSu32 refresh;	// Time in seconds that a slave waits after successful replication of the database before it attempts replication again
1428 	mDNSu32 retry;		// Time in seconds that a slave waits after an unsuccessful replication attempt before it attempts replication again
1429 	mDNSu32 expire;		// Time in seconds that a slave holds on to old data while replication attempts remain unsuccessful
1430 	mDNSu32 min;		// Nominally the minimum record TTL for this zone, in seconds; also used for negative caching.
1431 	} rdataSOA;
1432 
1433 typedef packedstruct
1434 	{
1435 	mDNSu16 vers;
1436 	mDNSu16 llqOp;
1437 	mDNSu16 err;
1438 	mDNSu8 id[8];
1439 	mDNSu32 lease;
1440 	} LLQOptData;
1441 
1442 #define LLQ_OPTLEN ((3 * sizeof(mDNSu16)) + 8 + sizeof(mDNSu32))
1443 // Windows adds pad bytes to sizeof(LLQOptData).  Use this macro when setting length fields or validating option rdata from
1444 // off the wire.  Use sizeof(LLQOptData) when dealing with structures (e.g. memcpy).  Never memcpy between on-the-wire
1445 // representation and a structure
1446 
1447 // NOTE: rdataOpt format may be repeated an arbitrary number of times in a single resource record
1448 typedef packedstruct
1449 	{
1450 	mDNSu16 opt;
1451 	mDNSu16 optlen;
1452 	union { LLQOptData llq; mDNSu32 lease; } OptData;
1453 	} rdataOpt;
1454 
1455 // StandardAuthRDSize is 264 (256+8), which is large enough to hold a maximum-sized SRV record
1456 // MaximumRDSize is 8K the absolute maximum we support (at least for now)
1457 #define StandardAuthRDSize 264
1458 #define MaximumRDSize 8192
1459 
1460 // InlineCacheRDSize is 68
1461 // Records received from the network with rdata this size or less have their rdata stored right in the CacheRecord object
1462 // Records received from the network with rdata larger than this have additional storage allocated for the rdata
1463 // A quick unscientific sample from a busy network at Apple with lots of machines revealed this:
1464 // 1461 records in cache
1465 // 292 were one-byte TXT records
1466 // 136 were four-byte A records
1467 // 184 were sixteen-byte AAAA records
1468 // 780 were various PTR, TXT and SRV records from 12-64 bytes
1469 // Only 69 records had rdata bigger than 64 bytes
1470 // Note that since CacheRecord object and a CacheGroup object are allocated out of the same pool, it's sensible to
1471 // have them both be the same size. Making one smaller without making the other smaller won't actually save any memory.
1472 #define InlineCacheRDSize 68
1473 
1474 #define InlineCacheGroupNameSize 144
1475 
1476 typedef union
1477 	{
1478 	mDNSu8      data[StandardAuthRDSize];
1479 	mDNSv4Addr  ipv4;		// For 'A' record
1480 	mDNSv6Addr  ipv6;		// For 'AAAA' record
1481 	domainname  name;		// For PTR, NS, and CNAME records
1482 	UTF8str255  txt;		// For TXT record
1483 	rdataSRV    srv;		// For SRV record
1484 	rdataMX     mx;			// For MX record
1485 	rdataSOA    soa;        // For SOA record
1486 	rdataOpt    opt;        // For eDNS0 opt record
1487 	} RDataBody;
1488 
1489 typedef struct
1490 	{
1491 	mDNSu16    MaxRDLength;	// Amount of storage allocated for rdata (usually sizeof(RDataBody))
1492 	RDataBody  u;
1493 	} RData;
1494 #define sizeofRDataHeader (sizeof(RData) - sizeof(RDataBody))
1495 
1496 typedef struct AuthRecord_struct AuthRecord;
1497 typedef struct CacheRecord_struct CacheRecord;
1498 typedef struct CacheGroup_struct CacheGroup;
1499 typedef struct DNSQuestion_struct DNSQuestion;
1500 typedef struct mDNS_struct mDNS;
1501 typedef struct mDNS_PlatformSupport_struct mDNS_PlatformSupport;
1502 typedef struct NATTraversalInfo_struct NATTraversalInfo;
1503 
1504 // Note: Within an mDNSRecordCallback mDNS all API calls are legal except mDNS_Init(), mDNS_Close(), mDNS_Execute()
1505 typedef void mDNSRecordCallback(mDNS *const m, AuthRecord *const rr, mStatus result);
1506 
1507 // Note:
1508 // Restrictions: An mDNSRecordUpdateCallback may not make any mDNS API calls.
1509 // The intent of this callback is to allow the client to free memory, if necessary.
1510 // The internal data structures of the mDNS code may not be in a state where mDNS API calls may be made safely.
1511 typedef void mDNSRecordUpdateCallback(mDNS *const m, AuthRecord *const rr, RData *OldRData);
1512 
1513 typedef struct
1514 	{
1515 	mDNSu8          RecordType;			// See enum above
1516 	mDNSInterfaceID InterfaceID;		// Set if this RR is specific to one interface
1517 										// For records received off the wire, InterfaceID is *always* set to the receiving interface
1518 										// For our authoritative records, InterfaceID is usually zero, except for those few records
1519 										// that are interface-specific (e.g. address records, especially linklocal addresses)
1520 	domainname     *name;
1521 	mDNSu16         rrtype;
1522 	mDNSu16         rrclass;
1523 	mDNSu32         rroriginalttl;		// In seconds
1524 	mDNSu16         rdlength;			// Size of the raw rdata, in bytes
1525 	mDNSu16         rdestimate;			// Upper bound on size of rdata after name compression
1526 	mDNSu32         namehash;			// Name-based (i.e. case-insensitive) hash of name
1527 	mDNSu32         rdatahash;			// For rdata containing domain name (e.g. PTR, SRV, CNAME etc.), case-insensitive name hash
1528 										// else, for all other rdata, 32-bit hash of the raw rdata
1529 										// Note: This requirement is important. Various routines like AddAdditionalsToResponseList(),
1530 										// ReconfirmAntecedents(), etc., use rdatahash as a pre-flight check to see
1531 										// whether it's worth doing a full SameDomainName() call. If the rdatahash
1532 										// is not a correct case-insensitive name hash, they'll get false negatives.
1533 	RData           *rdata;				// Pointer to storage for this rdata
1534 	} ResourceRecord;
1535 
1536 // Unless otherwise noted, states may apply to either independent record registrations or service registrations
1537 typedef enum
1538 	{
1539 	regState_FetchingZoneData  = 1,     // getting info - update not sent
1540 	regState_Pending           = 2,     // update sent, reply not received
1541 	regState_Registered        = 3,     // update sent, reply received
1542 	regState_DeregPending      = 4,     // dereg sent, reply not received
1543 	regState_DeregDeferred     = 5,     // dereg requested while in Pending state - send dereg AFTER registration is confirmed
1544 	regState_Cancelled         = 6,     // update not sent, reg. cancelled by client
1545 	regState_Unregistered      = 8,     // not in any list
1546 	regState_Refresh           = 9,     // outstanding refresh (or target change) message
1547 	regState_NATMap            = 10,    // establishing NAT port mapping or learning public address
1548 	regState_UpdatePending     = 11,    // update in flight as result of mDNS_Update call
1549 	regState_NoTarget          = 12,    // service registration pending registration of hostname (ServiceRegistrations only)
1550     regState_ExtraQueued       = 13,    // extra record to be registered upon completion of service registration (RecordRegistrations only)
1551 	regState_NATError          = 14     // unable to complete NAT traversal
1552 	} regState_t;
1553 
1554 // context for both ServiceRecordSet and individual AuthRec structs
1555 typedef struct
1556 	{
1557 	// registration/lease state
1558 	regState_t   state;
1559 	mDNSBool     lease;    // dynamic update contains (should contain) lease option
1560 	mDNSs32      expire;   // expiration of lease (-1 for static)
1561 	mDNSBool     TestForSelfConflict;  // on name conflict, check if we're just seeing our own orphaned records
1562 
1563 	// identifier to match update request and response
1564 	mDNSOpaque16 id;
1565 
1566 	// server info
1567 	domainname   zone;     // the zone that is updated
1568 	mDNSAddr     ns;       // primary name server for the record's zone    !!!KRS not technically correct to cache longer than TTL
1569 	mDNSIPPort   port;     // port on which server accepts dynamic updates
1570 
1571 	// NAT traversal context
1572 	NATTraversalInfo *NATinfo; // may be NULL
1573 
1574 	// state for deferred operations
1575     mDNSBool     ClientCallbackDeferred;  // invoke client callback on completion of pending operation(s)
1576 	mStatus      DeferredStatus;          // status to deliver when above flag is set
1577     mDNSBool     SRVUpdateDeferred;       // do we need to change target or port once current operation completes?
1578     mDNSBool     SRVChanged;              // temporarily deregistered service because its SRV target or port changed
1579 
1580     // uDNS_UpdateRecord support fields
1581     RData *OrigRData;      mDNSu16 OrigRDLen;     // previously registered, being deleted
1582     RData *InFlightRData;  mDNSu16 InFlightRDLen; // currently being registered
1583     RData *QueuedRData;    mDNSu16 QueuedRDLen;   // if the client call Update while an update is in flight, we must finish the
1584                                                   // pending operation (re-transmitting if necessary) THEN register the queued update
1585 	mDNSRecordUpdateCallback *UpdateRDCallback;   // client callback to free old rdata
1586 	} uDNS_RegInfo;
1587 
1588 struct AuthRecord_struct
1589 	{
1590 	// For examples of how to set up this structure for use in mDNS_Register(),
1591 	// see mDNS_AdvertiseInterface() or mDNS_RegisterService().
1592 	// Basically, resrec and persistent metadata need to be set up before calling mDNS_Register().
1593 	// mDNS_SetupResourceRecord() is avaliable as a helper routine to set up most fields to sensible default values for you
1594 
1595 	AuthRecord     *next;				// Next in list; first element of structure for efficiency reasons
1596 	// Field Group 1: Common ResourceRecord fields
1597 	ResourceRecord  resrec;
1598 	uDNS_RegInfo uDNS_info;
1599 
1600 	// Field Group 2: Persistent metadata for Authoritative Records
1601 	AuthRecord     *Additional1;		// Recommended additional record to include in response
1602 	AuthRecord     *Additional2;		// Another additional
1603 	AuthRecord     *DependentOn;		// This record depends on another for its uniqueness checking
1604 	AuthRecord     *RRSet;				// This unique record is part of an RRSet
1605 	mDNSRecordCallback *RecordCallback;	// Callback function to call for state changes, and to free memory asynchronously on deregistration
1606 	void           *RecordContext;		// Context parameter for the callback function
1607 	mDNSu8          HostTarget;			// Set if the target of this record (PTR, CNAME, SRV, etc.) is our host name
1608 	mDNSu8          AllowRemoteQuery;	// Set if we allow hosts not on the local link to query this record
1609 	mDNSu8          ForceMCast;			// Set by client to advertise solely via multicast, even for apparently unicast names
1610 
1611 	// Field Group 3: Transient state for Authoritative Records
1612 	mDNSu8          Acknowledged;		// Set if we've given the success callback to the client
1613 	mDNSu8          ProbeCount;			// Number of probes remaining before this record is valid (kDNSRecordTypeUnique)
1614 	mDNSu8          AnnounceCount;		// Number of announcements remaining (kDNSRecordTypeShared)
1615 	mDNSu8          RequireGoodbye;		// Set if this RR has been announced on the wire and will require a goodbye packet
1616 	mDNSu8          LocalAnswer;		// Set if this RR has been delivered to LocalOnly questions
1617 	mDNSu8          IncludeInProbe;		// Set if this RR is being put into a probe right now
1618 	mDNSInterfaceID ImmedAnswer;		// Someone on this interface issued a query we need to answer (all-ones for all interfaces)
1619 	mDNSu8          ImmedUnicast;		// Set if we may send our response directly via unicast to the requester
1620 #if MDNS_LOG_ANSWER_SUPPRESSION_TIMES
1621 	mDNSs32         ImmedAnswerMarkTime;
1622 #endif
1623 	mDNSInterfaceID ImmedAdditional;	// Hint that we might want to also send this record, just to be helpful
1624 	mDNSInterfaceID SendRNow;			// The interface this query is being sent on right now
1625 	mDNSv4Addr      v4Requester;		// Recent v4 query for this record, or all-ones if more than one recent query
1626 	mDNSv6Addr      v6Requester;		// Recent v6 query for this record, or all-ones if more than one recent query
1627 	AuthRecord     *NextResponse;		// Link to the next element in the chain of responses to generate
1628 	const mDNSu8   *NR_AnswerTo;		// Set if this record was selected by virtue of being a direct answer to a question
1629 	AuthRecord     *NR_AdditionalTo;	// Set if this record was selected by virtue of being additional to another
1630 	mDNSs32         ThisAPInterval;		// In platform time units: Current interval for announce/probe
1631 	mDNSs32         AnnounceUntil;		// In platform time units: Creation time + TTL
1632 	mDNSs32         LastAPTime;			// In platform time units: Last time we sent announcement/probe
1633 	mDNSs32         LastMCTime;			// Last time we multicast this record (used to guard against packet-storm attacks)
1634 	mDNSInterfaceID LastMCInterface;	// Interface this record was multicast on at the time LastMCTime was recorded
1635 	RData          *NewRData;			// Set if we are updating this record with new rdata
1636 	mDNSu16         newrdlength;		// ... and the length of the new RData
1637 	mDNSRecordUpdateCallback *UpdateCallback;
1638 	mDNSu32         UpdateCredits;		// Token-bucket rate limiting of excessive updates
1639 	mDNSs32         NextUpdateCredit;	// Time next token is added to bucket
1640 	mDNSs32         UpdateBlocked;		// Set if update delaying is in effect
1641 
1642 	domainname      namestorage;
1643 	RData           rdatastorage;		// Normally the storage is right here, except for oversized records
1644 	// rdatastorage MUST be the last thing in the structure -- when using oversized AuthRecords, extra bytes
1645 	// are appended after the end of the AuthRecord, logically augmenting the size of the rdatastorage
1646 	// DO NOT ADD ANY MORE FIELDS HERE
1647 	};
1648 
1649 // Wrapper struct for Auth Records for higher-level code that cannot use the AuthRecord's ->next pointer field
1650 typedef struct ARListElem
1651 	{
1652 	struct ARListElem *next;
1653 	AuthRecord ar;          // Note: Must be last struct in field to accomodate oversized AuthRecords
1654 	} ARListElem;
1655 
1656 struct CacheGroup_struct				// Header object for a list of CacheRecords with the same name
1657 	{
1658 	CacheGroup     *next;				// Next CacheGroup object in this hash table bucket
1659 	mDNSu32         namehash;			// Name-based (i.e. case insensitive) hash of name
1660 	CacheRecord    *members;			// List of CacheRecords with this same name
1661 	CacheRecord   **rrcache_tail;		// Tail end of that list
1662 	domainname     *name;				// Common name for all CacheRecords in this list
1663 	mDNSu8          namestorage[InlineCacheGroupNameSize];
1664 	};
1665 
1666 struct CacheRecord_struct
1667 	{
1668 	CacheRecord    *next;				// Next in list; first element of structure for efficiency reasons
1669 	ResourceRecord  resrec;
1670 
1671 	// Transient state for Cache Records
1672 	CacheRecord    *NextInKAList;		// Link to the next element in the chain of known answers to send
1673 	mDNSs32         TimeRcvd;			// In platform time units
1674 	mDNSs32         DelayDelivery;		// Set if we want to defer delivery of this answer to local clients
1675 	mDNSs32         NextRequiredQuery;	// In platform time units
1676 	mDNSs32         LastUsed;			// In platform time units
1677 	DNSQuestion    *CRActiveQuestion;	// Points to an active question referencing this answer
1678 	mDNSu32         UnansweredQueries;	// Number of times we've issued a query for this record without getting an answer
1679 	mDNSs32         LastUnansweredTime;	// In platform time units; last time we incremented UnansweredQueries
1680 	mDNSu32         MPUnansweredQ;		// Multi-packet query handling: Number of times we've seen a query for this record
1681 	mDNSs32         MPLastUnansweredQT;	// Multi-packet query handling: Last time we incremented MPUnansweredQ
1682 	mDNSu32         MPUnansweredKA;		// Multi-packet query handling: Number of times we've seen this record in a KA list
1683 	mDNSBool        MPExpectingKA;		// Multi-packet query handling: Set when we increment MPUnansweredQ; allows one KA
1684 	CacheRecord    *NextInCFList;		// Set if this is in the list of records we just received with the cache flush bit set
1685 
1686 	struct { mDNSu16 MaxRDLength; mDNSu8 data[InlineCacheRDSize]; } rdatastorage;	// Storage for small records is right here
1687 	};
1688 
1689 // Storage sufficient to hold either a CacheGroup header or a CacheRecord
1690 typedef union CacheEntity_union CacheEntity;
1691 union CacheEntity_union { CacheEntity *next; CacheGroup cg; CacheRecord cr; };
1692 
1693 typedef struct
1694 	{
1695 	CacheRecord r;
1696 	mDNSu8 _extradata[MaximumRDSize-InlineCacheRDSize];		// Glue on the necessary number of extra bytes
1697 	domainname namestorage;									// Needs to go *after* the extra rdata bytes
1698 	} LargeCacheRecord;
1699 
1700 typedef struct uDNS_HostnameInfo
1701 	{
1702 	struct uDNS_HostnameInfo *next;
1703     domainname fqdn;
1704     AuthRecord *arv4;                         // registered IPv4 address record
1705 	AuthRecord *arv6;                         // registered IPv6 address record
1706 	mDNSRecordCallback *StatusCallback;       // callback to deliver success or error code to client layer
1707 	const void *StatusContext;                // Client Context
1708 	} uDNS_HostnameInfo;
1709 
1710 enum
1711    	{
1712    	DNSServer_Untested = 0,
1713    	DNSServer_Failed   = 1,
1714    	DNSServer_Passed   = 2
1715    	};
1716 
1717 typedef struct DNSServer
1718 	{
1719     struct DNSServer *next;
1720     mDNSAddr   addr;
1721     mDNSBool   del;			// Set when we're planning to delete this from the list
1722     mDNSu32    teststate;	// Have we sent bug-detection query to this server?
1723     domainname domain;		// name->server matching for "split dns"
1724 	} DNSServer;
1725 
1726 typedef struct NetworkInterfaceInfo_struct NetworkInterfaceInfo;
1727 
1728 // A NetworkInterfaceInfo_struct serves two purposes:
1729 // 1. It holds the address, PTR and HINFO records to advertise a given IP address on a given physical interface
1730 // 2. It tells mDNSCore which physical interfaces are available; each physical interface has its own unique InterfaceID.
1731 //    Since there may be multiple IP addresses on a single physical interface,
1732 //    there may be multiple NetworkInterfaceInfo_structs with the same InterfaceID.
1733 //    In this case, to avoid sending the same packet n times, when there's more than one
1734 //    struct with the same InterfaceID, mDNSCore picks one member of the set to be the
1735 //    active representative of the set; all others have the 'InterfaceActive' flag unset.
1736 
1737 struct NetworkInterfaceInfo_struct
1738 	{
1739 	// Internal state fields. These are used internally by mDNSCore; the client layer needn't be concerned with them.
1740 	NetworkInterfaceInfo *next;
1741 
1742 	mDNSBool        InterfaceActive;	// Set if interface is sending & receiving packets (see comment above)
1743 	mDNSBool        IPv4Available;		// If InterfaceActive, set if v4 available on this InterfaceID
1744 	mDNSBool        IPv6Available;		// If InterfaceActive, set if v6 available on this InterfaceID
1745 
1746 	// Standard AuthRecords that every Responder host should have (one per active IP address)
1747 	AuthRecord RR_A;					// 'A' or 'AAAA' (address) record for our ".local" name
1748 	AuthRecord RR_PTR;					// PTR (reverse lookup) record
1749 	AuthRecord RR_HINFO;
1750 
1751 	// Client API fields: The client must set up these fields *before* calling mDNS_RegisterInterface()
1752 	mDNSInterfaceID InterfaceID;		// Identifies physical interface; MUST NOT be 0, -1, or -2
1753 	mDNSAddr        ip;					// The IPv4 or IPv6 address to advertise
1754 	mDNSAddr        mask;
1755 	char            ifname[64];			// Windows uses a GUID string for the interface name, which doesn't fit in 16 bytes
1756 	mDNSBool        Advertise;			// False if you are only searching on this interface
1757 	mDNSBool        McastTxRx;			// Send/Receive multicast on this { InterfaceID, address family } ?
1758 	};
1759 
1760 typedef struct ExtraResourceRecord_struct ExtraResourceRecord;
1761 struct ExtraResourceRecord_struct
1762 	{
1763 	ExtraResourceRecord *next;
1764     mDNSu32 ClientID;  // Opaque ID field to be used by client to map an AddRecord call to a set of Extra records
1765 	AuthRecord r;
1766 	// Note: Add any additional fields *before* the AuthRecord in this structure, not at the end.
1767 	// In some cases clients can allocate larger chunks of memory and set r->rdata->MaxRDLength to indicate
1768 	// that this extra memory is available, which would result in any fields after the AuthRecord getting smashed
1769 	};
1770 
1771 // Note: Within an mDNSServiceCallback mDNS all API calls are legal except mDNS_Init(), mDNS_Close(), mDNS_Execute()
1772 typedef struct ServiceRecordSet_struct ServiceRecordSet;
1773 typedef void mDNSServiceCallback(mDNS *const m, ServiceRecordSet *const sr, mStatus result);
1774 struct ServiceRecordSet_struct
1775 	{
1776 	// Internal state fields. These are used internally by mDNSCore; the client layer needn't be concerned with them.
1777 	// No fields need to be set up by the client prior to calling mDNS_RegisterService();
1778 	// all required data is passed as parameters to that function.
1779 	ServiceRecordSet    *next;
1780 	uDNS_RegInfo        uDNS_info;
1781 	mDNSServiceCallback *ServiceCallback;
1782 	void                *ServiceContext;
1783 	ExtraResourceRecord *Extras;	// Optional list of extra AuthRecords attached to this service registration
1784 	mDNSu32              NumSubTypes;
1785 	AuthRecord          *SubTypes;
1786 	mDNSBool             Conflict;	// Set if this record set was forcibly deregistered because of a conflict
1787 	domainname           Host;		// Set if this service record does not use the standard target host name
1788 	AuthRecord           RR_ADV;	// e.g. _services._dns-sd._udp.local. PTR _printer._tcp.local.
1789 	AuthRecord           RR_PTR;	// e.g. _printer._tcp.local.        PTR Name._printer._tcp.local.
1790 	AuthRecord           RR_SRV;	// e.g. Name._printer._tcp.local.   SRV 0 0 port target
1791 	AuthRecord           RR_TXT;	// e.g. Name._printer._tcp.local.   TXT PrintQueueName
1792 	// Don't add any fields after AuthRecord RR_TXT.
1793 	// This is where the implicit extra space goes if we allocate a ServiceRecordSet containing an oversized RR_TXT record
1794 	};
1795 
1796 // ***************************************************************************
1797 #if 0
1798 #pragma mark - Question structures
1799 #endif
1800 
1801 // We record the last eight instances of each duplicate query
1802 // This gives us v4/v6 on each of Ethernet/AirPort and Firewire, and two free slots "for future expansion"
1803 // If the host has more active interfaces that this it is not fatal -- duplicate question suppression will degrade gracefully.
1804 // Since we will still remember the last eight, the busiest interfaces will still get the effective duplicate question suppression.
1805 #define DupSuppressInfoSize 8
1806 
1807 typedef struct
1808 	{
1809 	mDNSs32               Time;
1810 	mDNSInterfaceID       InterfaceID;
1811 	mDNSs32               Type;				// v4 or v6?
1812 	} DupSuppressInfo;
1813 
1814 typedef enum
1815 	{
1816 	// Setup states
1817 	LLQ_UnInit            = 0,
1818 	LLQ_GetZoneInfo       = 1,
1819 	LLQ_InitialRequest    = 2,
1820 	LLQ_SecondaryRequest  = 3,
1821 	LLQ_Refresh           = 4,
1822 	LLQ_Retry             = 5,
1823 	LLQ_Established       = 6,
1824 	LLQ_Suspended         = 7,
1825 	LLQ_SuspendDeferred   = 8, // suspend once we get zone info
1826 	LLQ_SuspendedPoll     = 9, // suspended from polling state
1827 	LLQ_NatMapWait        = 10,
1828 
1829 	// Established/error states
1830 	LLQ_Static            = 16,
1831 	LLQ_Poll              = 17,
1832 	LLQ_Error             = 18,
1833 	LLQ_Cancelled         = 19
1834 	} LLQ_State;
1835 
1836 typedef struct
1837 	{
1838 	LLQ_State state;
1839 	mDNSAddr servAddr;
1840 	mDNSIPPort servPort;
1841 	DNSQuestion *question;
1842 	mDNSu32 origLease;  // seconds (relative)
1843 	mDNSs32 retry;  // ticks (absolute)
1844 	mDNSs32 expire; // ticks (absolute)
1845     mDNSs16 ntries;
1846 	mDNSu8 id[8];
1847 	mDNSBool deriveRemovesOnResume;
1848     mDNSBool NATMap;        // does this LLQ use the global LLQ NAT mapping?
1849 	} LLQ_Info;
1850 
1851 // LLQ constants
1852 #define kDNSOpt_LLQ	   1
1853 #define kDNSOpt_Lease  2
1854 #define kLLQ_Vers      1
1855 #define kLLQ_DefLease  7200 // 2 hours
1856 #define kLLQ_MAX_TRIES 3    // retry an operation 3 times max
1857 #define kLLQ_INIT_RESEND 2 // resend an un-ack'd packet after 2 seconds, then double for each additional
1858 #define kLLQ_DEF_RETRY 1800 // retry a failed operation after 30 minutes
1859 // LLQ Operation Codes
1860 #define kLLQOp_Setup     1
1861 #define kLLQOp_Refresh   2
1862 #define kLLQOp_Event     3
1863 
1864 #define LLQ_OPT_RDLEN ((2 * sizeof(mDNSu16)) + LLQ_OPTLEN)
1865 #define LEASE_OPT_RDLEN (2 * sizeof(mDNSu16)) + sizeof(mDNSs32)
1866 
1867 // LLQ Errror Codes
1868 enum
1869 	{
1870 	LLQErr_NoError = 0,
1871 	LLQErr_ServFull = 1,
1872 	LLQErr_Static = 2,
1873 	LLQErr_FormErr = 3,
1874 	LLQErr_NoSuchLLQ = 4,
1875 	LLQErr_BadVers = 5,
1876 	LLQErr_UnknownErr = 6
1877 	};
1878 
1879 typedef void (*InternalResponseHndlr)(mDNS *const m, DNSMessage *msg, const  mDNSu8 *end, DNSQuestion *question, void *internalContext);
1880 typedef struct
1881 	{
1882 	mDNSOpaque16          id;
1883 	mDNSBool              internal;
1884 	InternalResponseHndlr responseCallback;   // NULL if internal field is false
1885 	LLQ_Info              *llq;               // NULL for 1-shot queries
1886     mDNSBool              Answered;           // have we received an answer (including NXDOMAIN) for this question?
1887     CacheRecord           *knownAnswers;
1888     mDNSs32               RestartTime;        // Mark when we restart a suspended query
1889     void *context;
1890 	} uDNS_QuestionInfo;
1891 
1892 // Note: Within an mDNSQuestionCallback mDNS all API calls are legal except mDNS_Init(), mDNS_Close(), mDNS_Execute()
1893 typedef void mDNSQuestionCallback(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, mDNSBool AddRecord);
1894 struct DNSQuestion_struct
1895 	{
1896 	// Internal state fields. These are used internally by mDNSCore; the client layer needn't be concerned with them.
1897 	DNSQuestion          *next;
1898 	mDNSu32               qnamehash;
1899 	mDNSs32               DelayAnswering;	// Set if we want to defer answering this question until the cache settles
1900 	mDNSs32               LastQTime;		// Last scheduled transmission of this Q on *all* applicable interfaces
1901 	mDNSs32               ThisQInterval;	// LastQTime + ThisQInterval is the next scheduled transmission of this Q
1902 											// ThisQInterval > 0 for an active question;
1903 											// ThisQInterval = 0 for a suspended question that's still in the list
1904 											// ThisQInterval = -1 for a cancelled question that's been removed from the list
1905 	mDNSs32               LastAnswerPktNum;	// The sequence number of the last response packet containing an answer to this Q
1906 	mDNSu32               RecentAnswerPkts;	// Number of answers since the last time we sent this query
1907 	mDNSu32               CurrentAnswers;	// Number of records currently in the cache that answer this question
1908 	mDNSu32               LargeAnswers;		// Number of answers with rdata > 1024 bytes
1909 	mDNSu32               UniqueAnswers;	// Number of answers received with kDNSClass_UniqueRRSet bit set
1910 	mDNSInterfaceID       FlappingInterface;// Set when an interface goes away, to flag if removes are delivered for this Q
1911 	DNSQuestion          *DuplicateOf;
1912 	DNSQuestion          *NextInDQList;
1913 	DupSuppressInfo       DupSuppress[DupSuppressInfoSize];
1914 	mDNSInterfaceID       SendQNow;			// The interface this query is being sent on right now
1915 	mDNSBool              SendOnAll;		// Set if we're sending this question on all active interfaces
1916 	mDNSu32               RequestUnicast;	// Non-zero if we want to send query with kDNSQClass_UnicastResponse bit set
1917 	mDNSs32               LastQTxTime;		// Last time this Q was sent on one (but not necessarily all) interfaces
1918 	uDNS_QuestionInfo     uDNS_info;
1919 
1920 	// Client API fields: The client must set up these fields *before* calling mDNS_StartQuery()
1921 	mDNSInterfaceID       InterfaceID;		// Non-zero if you want to issue queries only on a single specific IP interface
1922 	mDNSAddr              Target;			// Non-zero if you want to direct queries to a specific unicast target address
1923 	mDNSIPPort            TargetPort;		// Must be set if Target is set
1924 	mDNSOpaque16          TargetQID;		// Must be set if Target is set
1925 	domainname            qname;
1926 	mDNSu16               qtype;
1927 	mDNSu16               qclass;
1928 	mDNSBool              LongLived;        // Set by client for calls to mDNS_StartQuery to indicate LLQs to unicast layer.
1929 	mDNSBool              ExpectUnique;		// Set by client if it's expecting unique RR(s) for this question, not shared RRs
1930 	mDNSBool              ForceMCast;		// Set by client to force mDNS query, even for apparently uDNS names
1931 	mDNSBool              ReturnCNAME;		// Set by client to request callbacks for intermediate CNAME records
1932 	mDNSQuestionCallback *QuestionCallback;
1933 	void                 *QuestionContext;
1934 	};
1935 
1936 typedef struct
1937 	{
1938 	// Client API fields: The client must set up name and InterfaceID *before* calling mDNS_StartResolveService()
1939 	// When the callback is invoked, ip, port, TXTlen and TXTinfo will have been filled in with the results learned from the network.
1940 	domainname      name;
1941 	mDNSInterfaceID InterfaceID;		// ID of the interface the response was received on
1942 	mDNSAddr        ip;					// Remote (destination) IP address where this service can be accessed
1943 	mDNSIPPort      port;				// Port where this service can be accessed
1944 	mDNSu16         TXTlen;
1945 	mDNSu8          TXTinfo[2048];		// Additional demultiplexing information (e.g. LPR queue name)
1946 	} ServiceInfo;
1947 
1948 // Note: Within an mDNSServiceInfoQueryCallback mDNS all API calls are legal except mDNS_Init(), mDNS_Close(), mDNS_Execute()
1949 typedef struct ServiceInfoQuery_struct ServiceInfoQuery;
1950 typedef void mDNSServiceInfoQueryCallback(mDNS *const m, ServiceInfoQuery *query);
1951 struct ServiceInfoQuery_struct
1952 	{
1953 	// Internal state fields. These are used internally by mDNSCore; the client layer needn't be concerned with them.
1954 	// No fields need to be set up by the client prior to calling mDNS_StartResolveService();
1955 	// all required data is passed as parameters to that function.
1956 	// The ServiceInfoQuery structure memory is working storage for mDNSCore to discover the requested information
1957 	// and place it in the ServiceInfo structure. After the client has called mDNS_StopResolveService(), it may
1958 	// dispose of the ServiceInfoQuery structure while retaining the results in the ServiceInfo structure.
1959 	DNSQuestion                   qSRV;
1960 	DNSQuestion                   qTXT;
1961 	DNSQuestion                   qAv4;
1962 	DNSQuestion                   qAv6;
1963 	mDNSu8                        GotSRV;
1964 	mDNSu8                        GotTXT;
1965 	mDNSu8                        GotADD;
1966 	mDNSu32                       Answers;
1967 	ServiceInfo                  *info;
1968 	mDNSServiceInfoQueryCallback *ServiceInfoQueryCallback;
1969 	void                         *ServiceInfoQueryContext;
1970 	};
1971 
1972 // ***************************************************************************
1973 #if 0
1974 #pragma mark - NAT Traversal structures and constants
1975 #endif
1976 
1977 #define NATMAP_INIT_RETRY (mDNSPlatformOneSecond / 4)          // start at 250ms w/ exponential decay
1978 #define NATMAP_MAX_RETRY mDNSPlatformOneSecond                 // back off to once per second
1979 #define NATMAP_MAX_TRIES 3                                     // for max 3 tries
1980 #define NATMAP_DEFAULT_LEASE (60 * 60)  // lease life in seconds
1981 #define NATMAP_VERS 0
1982 #define NATMAP_RESPONSE_MASK 0x80
1983 
1984 typedef enum
1985 	{
1986 	NATOp_AddrRequest = 0,
1987 	NATOp_MapUDP      = 1,
1988 	NATOp_MapTCP      = 2
1989 	} NATOp_t;
1990 
1991 enum
1992    	{
1993    	NATErr_None = 0,
1994    	NATErr_Vers = 1,
1995    	NATErr_Refused = 2,
1996    	NATErr_NetFail = 3,
1997    	NATErr_Res = 4,
1998    	NATErr_Opcode = 5
1999    	};
2000 
2001 typedef mDNSu16 NATErr_t;
2002 
2003 typedef enum
2004 	{
2005 	NATState_Init         = 0,
2006 	NATState_Request      = 1,
2007 	NATState_Established  = 2,
2008 	NATState_Legacy       = 3,
2009 	NATState_Error        = 4,
2010 	NATState_Refresh      = 5,
2011 	NATState_Deleted      = 6
2012 	} NATState_t;
2013 // Note: we have no explicit "cancelled" state, where a service/interface is deregistered while we
2014  // have an outstanding NAT request.  This is conveyed by the "reg" pointer being set to NULL
2015 
2016 typedef packedstruct
2017 	{
2018 	mDNSu8 vers;
2019 	mDNSu8 opcode;
2020 	} NATAddrRequest;
2021 
2022 typedef packedstruct
2023 	{
2024 	mDNSu8 vers;
2025 	mDNSu8 opcode;
2026 	mDNSOpaque16 err;
2027 	mDNSOpaque32 uptime;
2028 	mDNSv4Addr   PubAddr;
2029 	} NATAddrReply;
2030 
2031 typedef packedstruct
2032 	{
2033 	mDNSu8 vers;
2034 	mDNSu8 opcode;
2035 	mDNSOpaque16 unused;
2036 	mDNSIPPort priv;
2037 	mDNSIPPort pub;
2038 	mDNSOpaque32 lease;
2039 	} NATPortMapRequest;
2040 
2041 typedef packedstruct
2042 	{
2043 	mDNSu8 vers;
2044 	mDNSu8 opcode;
2045 	mDNSOpaque16 err;
2046 	mDNSOpaque32 uptime;
2047 	mDNSIPPort priv;
2048 	mDNSIPPort pub;
2049 	mDNSOpaque32 lease;
2050 	} NATPortMapReply;
2051 
2052 // Pass NULL for pkt on error (including timeout)
2053 typedef mDNSBool (*NATResponseHndlr)(NATTraversalInfo *n, mDNS *m, mDNSu8 *pkt, mDNSu16 len);
2054 
2055 struct NATTraversalInfo_struct
2056 	{
2057 	NATOp_t op;
2058 	NATResponseHndlr ReceiveResponse;
2059 	union { AuthRecord *RecordRegistration; ServiceRecordSet *ServiceRegistration; } reg;
2060     mDNSAddr Router;
2061     mDNSIPPort PublicPort;
2062     union { NATAddrRequest AddrReq; NATPortMapRequest PortReq; } request;
2063 	mDNSs32 retry;                   // absolute time when we retry
2064 	mDNSs32 RetryInterval;           // delta between time sent and retry
2065 	int ntries;
2066 	NATState_t state;
2067 	NATTraversalInfo *next;
2068 	};
2069 
2070 // ***************************************************************************
2071 #if 0
2072 #pragma mark - Main mDNS object, used to hold all the mDNS state
2073 #endif
2074 
2075 typedef void mDNSCallback(mDNS *const m, mStatus result);
2076 
2077 #define CACHE_HASH_SLOTS 499
2078 
2079 enum
2080 	{
2081 	mDNS_KnownBug_PhantomInterfaces = 1
2082 	};
2083 
2084 typedef struct
2085 	{
2086 	mDNSs32          nextevent;
2087 	DNSQuestion      *ActiveQueries;     //!!!KRS this should be a hashtable (hash on messageID)
2088 	DNSQuestion      *CurrentQuery;      // pointer to ActiveQueries list being examined in a loop.  Functions that remove
2089 										 // elements from the ActiveQueries list must update this pointer (if non-NULL) as necessary.
2090 										 //!!!KRS do the same for registration lists
2091 	ServiceRecordSet *ServiceRegistrations;
2092 	AuthRecord       *RecordRegistrations;
2093 	NATTraversalInfo *NATTraversals;
2094 	mDNSu16          NextMessageID;
2095     DNSServer        *Servers;           // list of DNS servers
2096 	mDNSAddr         Router;
2097 	mDNSAddr         AdvertisedV4;       // IPv4 address pointed to by hostname
2098 	mDNSAddr         MappedV4;           // Cache of public address if PrimaryIP is behind a NAT
2099 	mDNSAddr         AdvertisedV6;       // IPv6 address pointed to by hostname
2100     NATTraversalInfo *LLQNatInfo;        // Nat port mapping to receive LLQ events
2101 	domainname       ServiceRegDomain;   // (going away w/ multi-user support)
2102 	struct uDNS_AuthInfo *AuthInfoList;  // list of domains requiring authentication for updates.
2103 	uDNS_HostnameInfo *Hostnames;        // List of registered hostnames + hostname metadata
2104     DNSQuestion      ReverseMap;         // Reverse-map query to find static hostname for service target
2105     mDNSBool         ReverseMapActive;   // Is above query active?
2106     domainname       StaticHostname;     // Current answer to reverse-map query (above)
2107     mDNSBool         DelaySRVUpdate;     // Delay SRV target/port update to avoid "flap"
2108     mDNSs32          NextSRVUpdate;      // Time to perform delayed update
2109 	} uDNS_GlobalInfo;
2110 
2111 struct mDNS_struct
2112 	{
2113 	// Internal state fields. These hold the main internal state of mDNSCore;
2114 	// the client layer needn't be concerned with them.
2115 	// No fields need to be set up by the client prior to calling mDNS_Init();
2116 	// all required data is passed as parameters to that function.
2117 
2118 	mDNS_PlatformSupport *p;			// Pointer to platform-specific data of indeterminite size
2119 	mDNSu32  KnownBugs;
2120 	mDNSBool CanReceiveUnicastOn5353;
2121 	mDNSBool AdvertiseLocalAddresses;
2122 	mStatus mDNSPlatformStatus;
2123 	mDNSIPPort UnicastPort4;
2124 	mDNSIPPort UnicastPort6;
2125 	mDNSCallback *MainCallback;
2126 	void         *MainContext;
2127 
2128 	// For debugging: To catch and report locking failures
2129 	mDNSu32 mDNS_busy;					// Incremented between mDNS_Lock/mDNS_Unlock section
2130 	mDNSu32 mDNS_reentrancy;			// Incremented when calling a client callback
2131 	mDNSu8  mDNS_shutdown;				// Set when we're shutting down, allows us to skip some unnecessary steps
2132 	mDNSu8  lock_rrcache;				// For debugging: Set at times when these lists may not be modified
2133 	mDNSu8  lock_Questions;
2134 	mDNSu8  lock_Records;
2135 	#define MaxMsg 120
2136 	char MsgBuffer[MaxMsg];				// Temp storage used while building error log messages
2137 
2138 	// Task Scheduling variables
2139 	mDNSs32  timenow_adjust;			// Correction applied if we ever discover time went backwards
2140 	mDNSs32  timenow;					// The time that this particular activation of the mDNS code started
2141 	mDNSs32  timenow_last;				// The time the last time we ran
2142 	mDNSs32  NextScheduledEvent;		// Derived from values below
2143 	mDNSs32  SuppressSending;			// Don't send *any* packets during this time
2144 	mDNSs32  NextCacheCheck;			// Next time to refresh cache record before it expires
2145 	mDNSs32  NextScheduledQuery;		// Next time to send query in its exponential backoff sequence
2146 	mDNSs32  NextScheduledProbe;		// Next time to probe for new authoritative record
2147 	mDNSs32  NextScheduledResponse;		// Next time to send authoritative record(s) in responses
2148 	mDNSs32  ExpectUnicastResponse;		// Set when we send a query with the kDNSQClass_UnicastResponse bit set
2149 	mDNSs32  RandomQueryDelay;			// For de-synchronization of query packets on the wire
2150 	mDNSu32  RandomReconfirmDelay;		// For de-synchronization of reconfirmation queries on the wire
2151 	mDNSs32  PktNum;					// Unique sequence number assigned to each received packet
2152 	mDNSBool SendDeregistrations;		// Set if we need to send deregistrations (immediately)
2153 	mDNSBool SendImmediateAnswers;		// Set if we need to send answers (immediately -- or as soon as SuppressSending clears)
2154 	mDNSBool SleepState;				// Set if we're sleeping (send no more packets)
2155 
2156 	// These fields only required for mDNS Searcher...
2157 	DNSQuestion *Questions;				// List of all registered questions, active and inactive
2158 	DNSQuestion *NewQuestions;			// Fresh questions not yet answered from cache
2159 	DNSQuestion *CurrentQuestion;		// Next question about to be examined in AnswerLocalQuestions()
2160 	DNSQuestion *LocalOnlyQuestions;	// Questions with InterfaceID set to mDNSInterface_LocalOnly
2161 	DNSQuestion *NewLocalOnlyQuestions;	// Fresh local-only questions not yet answered
2162 	mDNSu32 rrcache_size;				// Total number of available cache entries
2163 	mDNSu32 rrcache_totalused;			// Number of cache entries currently occupied
2164 	mDNSu32 rrcache_active;				// Number of cache entries currently occupied by records that answer active questions
2165 	mDNSu32 rrcache_report;
2166 	CacheEntity *rrcache_free;
2167 	CacheGroup *rrcache_hash[CACHE_HASH_SLOTS];
2168 
2169 	// Fields below only required for mDNS Responder...
2170 	domainlabel nicelabel;				// Rich text label encoded using canonically precomposed UTF-8
2171 	domainlabel hostlabel;				// Conforms to RFC 1034 "letter-digit-hyphen" ARPANET host name rules
2172 	domainname  MulticastHostname;		// Fully Qualified "dot-local" Host Name, e.g. "Foo.local."
2173 	UTF8str255  HIHardware;
2174 	UTF8str255  HISoftware;
2175 	AuthRecord *ResourceRecords;
2176 	AuthRecord *DuplicateRecords;		// Records currently 'on hold' because they are duplicates of existing records
2177 	AuthRecord *NewLocalRecords;		// Fresh local-only records not yet delivered to local-only questions
2178 	AuthRecord *CurrentRecord;			// Next AuthRecord about to be examined
2179 	NetworkInterfaceInfo *HostInterfaces;
2180 	mDNSs32 ProbeFailTime;
2181 	mDNSu32 NumFailedProbes;
2182 	mDNSs32 SuppressProbes;
2183 
2184 	// unicast-specific data
2185 	uDNS_GlobalInfo uDNS_info;
2186 	mDNSs32 SuppressStdPort53Queries;	// Wait before allowing the next standard unicast query to the user's configured DNS server
2187 
2188 	// Fixed storage, to avoid creating large objects on the stack
2189 	DNSMessage imsg;		// Incoming message received from wire
2190 	DNSMessage omsg;		// Outgoing message we're building
2191 	LargeCacheRecord rec;	// Resource Record extracted from received message
2192 	};
2193 
2194 #define FORALL_CACHERECORDS(SLOT,CG,CR)                          \
2195 	for ((SLOT) = 0; (SLOT) < CACHE_HASH_SLOTS; (SLOT)++)        \
2196 		for((CG)=m->rrcache_hash[(SLOT)]; (CG); (CG)=(CG)->next) \
2197 			for ((CR) = (CG)->members; (CR); (CR)=(CR)->next)
2198 
2199 // ***************************************************************************
2200 #if 0
2201 #pragma mark - Useful Static Constants
2202 #endif
2203 
2204 extern const mDNSIPPort      zeroIPPort;
2205 extern const mDNSv4Addr      zerov4Addr;
2206 extern const mDNSv6Addr      zerov6Addr;
2207 extern const mDNSEthAddr     zeroEthAddr;
2208 extern const mDNSv4Addr      onesIPv4Addr;
2209 extern const mDNSv6Addr      onesIPv6Addr;
2210 extern const mDNSAddr        zeroAddr;
2211 
2212 extern const mDNSInterfaceID mDNSInterface_Any;				// Zero
2213 extern const mDNSInterfaceID mDNSInterface_LocalOnly;		// Special value
2214 
2215 extern const mDNSIPPort      UnicastDNSPort;
2216 extern const mDNSIPPort      NATPMPPort;
2217 extern const mDNSIPPort      DNSEXTPort;
2218 extern const mDNSIPPort      MulticastDNSPort;
2219 extern const mDNSIPPort      LoopbackIPCPort;
2220 
2221 extern const mDNSv4Addr      AllDNSAdminGroup;
2222 #define AllDNSLinkGroupv4 (AllDNSLinkGroup_v4.ip.v4)
2223 #define AllDNSLinkGroupv6 (AllDNSLinkGroup_v6.ip.v6)
2224 extern const mDNSAddr        AllDNSLinkGroup_v4;
2225 extern const mDNSAddr        AllDNSLinkGroup_v6;
2226 
2227 extern const mDNSOpaque16 zeroID;
2228 extern const mDNSOpaque16 QueryFlags;
2229 extern const mDNSOpaque16 uQueryFlags;
2230 extern const mDNSOpaque16 ResponseFlags;
2231 extern const mDNSOpaque16 UpdateReqFlags;
2232 extern const mDNSOpaque16 UpdateRespFlags;
2233 
2234 #define localdomain (*(const domainname *)"\x5" "local")
2235 #define LocalReverseMapDomain (*(const domainname *)"\x3" "254" "\x3" "169" "\x7" "in-addr" "\x4" "arpa")
2236 
2237 // ***************************************************************************
2238 #if 0
2239 #pragma mark - Inline functions
2240 #endif
2241 
2242 #if (defined(_MSC_VER))
2243 	#define mDNSinline static __inline
2244 #elif ((__GNUC__ > 2) || ((__GNUC__ == 2) && (__GNUC_MINOR__ >= 9)))
2245 	#define mDNSinline static inline
2246 #endif
2247 
2248 // If we're not doing inline functions, then this header needs to have the extern declarations
2249 #if !defined(mDNSinline)
2250 extern mDNSs32      NonZeroTime(mDNSs32 t);
2251 extern mDNSu16      mDNSVal16(mDNSOpaque16 x);
2252 extern mDNSu32      mDNSVal32(mDNSOpaque32 x);
2253 extern mDNSOpaque16 mDNSOpaque16fromIntVal(mDNSu16 v);
2254 extern mDNSOpaque32 mDNSOpaque32fromIntVal(mDNSu32 v);
2255 #endif
2256 
2257 // If we're compiling the particular C file that instantiates our inlines, then we
2258 // define "mDNSinline" (to empty string) so that we generate code in the following section
2259 #if (!defined(mDNSinline) && mDNS_InstantiateInlines)
2260 #define mDNSinline
2261 #endif
2262 
2263 #ifdef mDNSinline
2264 
NonZeroTime(mDNSs32 t)2265 mDNSinline mDNSs32 NonZeroTime(mDNSs32 t) { if (t) return(t); else return(1); }
2266 
mDNSVal16(mDNSOpaque16 x)2267 mDNSinline mDNSu16 mDNSVal16(mDNSOpaque16 x) { return((mDNSu16)((mDNSu16)x.b[0] <<  8 | (mDNSu16)x.b[1])); }
mDNSVal32(mDNSOpaque32 x)2268 mDNSinline mDNSu32 mDNSVal32(mDNSOpaque32 x) { return((mDNSu32)((mDNSu32)x.b[0] << 24 | (mDNSu32)x.b[1] << 16 | (mDNSu32)x.b[2] << 8 | (mDNSu32)x.b[3])); }
2269 
mDNSOpaque16fromIntVal(mDNSu16 v)2270 mDNSinline mDNSOpaque16 mDNSOpaque16fromIntVal(mDNSu16 v)
2271 	{
2272 	mDNSOpaque16 x;
2273 	x.b[0] = (mDNSu8)(v >> 8);
2274 	x.b[1] = (mDNSu8)(v & 0xFF);
2275 	return(x);
2276 	}
2277 
mDNSOpaque32fromIntVal(mDNSu32 v)2278 mDNSinline mDNSOpaque32 mDNSOpaque32fromIntVal(mDNSu32 v)
2279 	{
2280 	mDNSOpaque32 x;
2281 	x.b[0] = (mDNSu8) (v >> 24)        ;
2282 	x.b[1] = (mDNSu8)((v >> 16) & 0xFF);
2283 	x.b[2] = (mDNSu8)((v >> 8 ) & 0xFF);
2284 	x.b[3] = (mDNSu8)((v      ) & 0xFF);
2285 	return x;
2286 	}
2287 
2288 #endif
2289 
2290 // ***************************************************************************
2291 #if 0
2292 #pragma mark - Main Client Functions
2293 #endif
2294 
2295 // Every client should call mDNS_Init, passing in storage for the mDNS object and the mDNS_PlatformSupport object.
2296 //
2297 // Clients that are only advertising services should use mDNS_Init_NoCache and mDNS_Init_ZeroCacheSize.
2298 // Clients that plan to perform queries (mDNS_StartQuery, mDNS_StartBrowse, mDNS_StartResolveService, etc.)
2299 // need to provide storage for the resource record cache, or the query calls will return 'mStatus_NoCache'.
2300 // The rrcachestorage parameter is the address of memory for the resource record cache, and
2301 // the rrcachesize parameter is the number of entries in the CacheRecord array passed in.
2302 // (i.e. the size of the cache memory needs to be sizeof(CacheRecord) * rrcachesize).
2303 // OS X 10.3 Panther uses an initial cache size of 64 entries, and then mDNSCore sends an
2304 // mStatus_GrowCache message if it needs more.
2305 //
2306 // Most clients should use mDNS_Init_AdvertiseLocalAddresses. This causes mDNSCore to automatically
2307 // create the correct address records for all the hosts interfaces. If you plan to advertise
2308 // services being offered by the local machine, this is almost always what you want.
2309 // There are two cases where you might use mDNS_Init_DontAdvertiseLocalAddresses:
2310 // 1. A client-only device, that browses for services but doesn't advertise any of its own.
2311 // 2. A proxy-registration service, that advertises services being offered by other machines, and takes
2312 //    the appropriate steps to manually create the correct address records for those other machines.
2313 // In principle, a proxy-like registration service could manually create address records for its own machine too,
2314 // but this would be pointless extra effort when using mDNS_Init_AdvertiseLocalAddresses does that for you.
2315 //
2316 // When mDNS has finished setting up the client's callback is called
2317 // A client can also spin and poll the mDNSPlatformStatus field to see when it changes from mStatus_Waiting to mStatus_NoError
2318 //
2319 // Call mDNS_Close to tidy up before exiting
2320 //
2321 // Call mDNS_Register with a completed AuthRecord object to register a resource record
2322 // If the resource record type is kDNSRecordTypeUnique (or kDNSknownunique) then if a conflicting resource record is discovered,
2323 // the resource record's mDNSRecordCallback will be called with error code mStatus_NameConflict. The callback should deregister
2324 // the record, and may then try registering the record again after picking a new name (e.g. by automatically appending a number).
2325 // Following deregistration, the RecordCallback will be called with result mStatus_MemFree to signal that it is safe to deallocate
2326 // the record's storage (memory must be freed asynchronously to allow for goodbye packets and dynamic update deregistration).
2327 //
2328 // Call mDNS_StartQuery to initiate a query. mDNS will proceed to issue Multicast DNS query packets, and any time a response
2329 // is received containing a record which matches the question, the DNSQuestion's mDNSAnswerCallback function will be called
2330 // Call mDNS_StopQuery when no more answers are required
2331 //
2332 // Care should be taken on multi-threaded or interrupt-driven environments.
2333 // The main mDNS routines call mDNSPlatformLock() on entry and mDNSPlatformUnlock() on exit;
2334 // each platform layer needs to implement these appropriately for its respective platform.
2335 // For example, if the support code on a particular platform implements timer callbacks at interrupt time, then
2336 // mDNSPlatformLock/Unlock need to disable interrupts or do similar concurrency control to ensure that the mDNS
2337 // code is not entered by an interrupt-time timer callback while in the middle of processing a client call.
2338 
2339 extern mStatus mDNS_Init      (mDNS *const m, mDNS_PlatformSupport *const p,
2340 								CacheEntity *rrcachestorage, mDNSu32 rrcachesize,
2341 								mDNSBool AdvertiseLocalAddresses,
2342 								mDNSCallback *Callback, void *Context);
2343 // See notes above on use of NoCache/ZeroCacheSize
2344 #define mDNS_Init_NoCache                     mDNSNULL
2345 #define mDNS_Init_ZeroCacheSize               0
2346 // See notes above on use of Advertise/DontAdvertiseLocalAddresses
2347 #define mDNS_Init_AdvertiseLocalAddresses     mDNStrue
2348 #define mDNS_Init_DontAdvertiseLocalAddresses mDNSfalse
2349 #define mDNS_Init_NoInitCallback              mDNSNULL
2350 #define mDNS_Init_NoInitCallbackContext       mDNSNULL
2351 
2352 extern void    mDNS_GrowCache (mDNS *const m, CacheEntity *storage, mDNSu32 numrecords);
2353 extern void    mDNS_Close     (mDNS *const m);
2354 extern mDNSs32 mDNS_Execute   (mDNS *const m);
2355 
2356 extern mStatus mDNS_Register  (mDNS *const m, AuthRecord *const rr);
2357 extern mStatus mDNS_Update    (mDNS *const m, AuthRecord *const rr, mDNSu32 newttl,
2358 								const mDNSu16 newrdlength, RData *const newrdata, mDNSRecordUpdateCallback *Callback);
2359 extern mStatus mDNS_Deregister(mDNS *const m, AuthRecord *const rr);
2360 
2361 extern mStatus mDNS_StartQuery(mDNS *const m, DNSQuestion *const question);
2362 extern mStatus mDNS_StopQuery (mDNS *const m, DNSQuestion *const question);
2363 extern mStatus mDNS_Reconfirm (mDNS *const m, CacheRecord *const cacherr);
2364 extern mStatus mDNS_ReconfirmByValue(mDNS *const m, ResourceRecord *const rr);
2365 extern mDNSs32 mDNS_TimeNow(const mDNS *const m);
2366 
2367 // ***************************************************************************
2368 #if 0
2369 #pragma mark - Platform support functions that are accessible to the client layer too
2370 #endif
2371 
2372 extern mDNSs32  mDNSPlatformOneSecond;
2373 
2374 // ***************************************************************************
2375 #if 0
2376 #pragma mark - General utility and helper functions
2377 #endif
2378 
2379 // mDNS_RegisterService is a single call to register the set of resource records associated with a given named service.
2380 //
2381 // mDNS_StartResolveService is single call which is equivalent to multiple calls to mDNS_StartQuery,
2382 // to find the IP address, port number, and demultiplexing information for a given named service.
2383 // As with mDNS_StartQuery, it executes asynchronously, and calls the ServiceInfoQueryCallback when the answer is
2384 // found. After the service is resolved, the client should call mDNS_StopResolveService to complete the transaction.
2385 // The client can also call mDNS_StopResolveService at any time to abort the transaction.
2386 //
2387 // mDNS_AddRecordToService adds an additional record to a Service Record Set.  This record may be deregistered
2388 // via mDNS_RemoveRecordFromService, or by deregistering the service.  mDNS_RemoveRecordFromService is passed a
2389 // callback to free the memory associated with the extra RR when it is safe to do so.  The ExtraResourceRecord
2390 // object can be found in the record's context pointer.
2391 
2392 // mDNS_GetBrowseDomains is a special case of the mDNS_StartQuery call, where the resulting answers
2393 // are a list of PTR records indicating (in the rdata) domains that are recommended for browsing.
2394 // After getting the list of domains to browse, call mDNS_StopQuery to end the search.
2395 // mDNS_GetDefaultBrowseDomain returns the name of the domain that should be highlighted by default.
2396 //
2397 // mDNS_GetRegistrationDomains and mDNS_GetDefaultRegistrationDomain are the equivalent calls to get the list
2398 // of one or more domains that should be offered to the user as choices for where they may register their service,
2399 // and the default domain in which to register in the case where the user has made no selection.
2400 
2401 extern void    mDNS_SetupResourceRecord(AuthRecord *rr, RData *RDataStorage, mDNSInterfaceID InterfaceID,
2402                mDNSu16 rrtype, mDNSu32 ttl, mDNSu8 RecordType, mDNSRecordCallback Callback, void *Context);
2403 
2404 extern mStatus mDNS_RegisterService  (mDNS *const m, ServiceRecordSet *sr,
2405                const domainlabel *const name, const domainname *const type, const domainname *const domain,
2406                const domainname *const host, mDNSIPPort port, const mDNSu8 txtinfo[], mDNSu16 txtlen,
2407                AuthRecord *SubTypes, mDNSu32 NumSubTypes,
2408                const mDNSInterfaceID InterfaceID, mDNSServiceCallback Callback, void *Context);
2409 extern mStatus mDNS_AddRecordToService(mDNS *const m, ServiceRecordSet *sr, ExtraResourceRecord *extra, RData *rdata, mDNSu32 ttl);
2410 extern mStatus mDNS_RemoveRecordFromService(mDNS *const m, ServiceRecordSet *sr, ExtraResourceRecord *extra, mDNSRecordCallback MemFreeCallback, void *Context);
2411 extern mStatus mDNS_RenameAndReregisterService(mDNS *const m, ServiceRecordSet *const sr, const domainlabel *newname);
2412 extern mStatus mDNS_DeregisterService(mDNS *const m, ServiceRecordSet *sr);
2413 
2414 extern mStatus mDNS_RegisterNoSuchService(mDNS *const m, AuthRecord *const rr,
2415                const domainlabel *const name, const domainname *const type, const domainname *const domain,
2416                const domainname *const host,
2417                const mDNSInterfaceID InterfaceID, mDNSRecordCallback Callback, void *Context);
2418 #define        mDNS_DeregisterNoSuchService mDNS_Deregister
2419 
2420 extern mStatus mDNS_StartBrowse(mDNS *const m, DNSQuestion *const question,
2421                const domainname *const srv, const domainname *const domain,
2422                const mDNSInterfaceID InterfaceID, mDNSBool ForceMCast, mDNSQuestionCallback *Callback, void *Context);
2423 #define        mDNS_StopBrowse mDNS_StopQuery
2424 
2425 extern mStatus mDNS_StartResolveService(mDNS *const m, ServiceInfoQuery *query, ServiceInfo *info, mDNSServiceInfoQueryCallback *Callback, void *Context);
2426 extern void    mDNS_StopResolveService (mDNS *const m, ServiceInfoQuery *query);
2427 
2428 typedef enum
2429 	{
2430 	mDNS_DomainTypeBrowse              = 0,
2431 	mDNS_DomainTypeBrowseDefault       = 1,
2432 	mDNS_DomainTypeBrowseLegacy        = 2,
2433 	mDNS_DomainTypeRegistration        = 3,
2434 	mDNS_DomainTypeRegistrationDefault = 4,
2435 
2436 	mDNS_DomainTypeMax = 4
2437 	} mDNS_DomainType;
2438 
2439 extern const char *const mDNS_DomainTypeNames[];
2440 
2441 extern mStatus mDNS_GetDomains(mDNS *const m, DNSQuestion *const question, mDNS_DomainType DomainType, const domainname *dom,
2442 								const mDNSInterfaceID InterfaceID, mDNSQuestionCallback *Callback, void *Context);
2443 #define        mDNS_StopGetDomains mDNS_StopQuery
2444 extern mStatus mDNS_AdvertiseDomains(mDNS *const m, AuthRecord *rr, mDNS_DomainType DomainType, const mDNSInterfaceID InterfaceID, char *domname);
2445 #define        mDNS_StopAdvertiseDomains mDNS_Deregister
2446 
2447 // ***************************************************************************
2448 #if 0
2449 #pragma mark - DNS name utility functions
2450 #endif
2451 
2452 // In order to expose the full capabilities of the DNS protocol (which allows any arbitrary eight-bit values
2453 // in domain name labels, including unlikely characters like ascii nulls and even dots) all the mDNS APIs
2454 // work with DNS's native length-prefixed strings. For convenience in C, the following utility functions
2455 // are provided for converting between C's null-terminated strings and DNS's length-prefixed strings.
2456 
2457 // Assignment
2458 // A simple C structure assignment of a domainname can cause a protection fault by accessing unmapped memory,
2459 // because that object is defined to be 256 bytes long, but not all domainname objects are truly the full size.
2460 // This macro uses mDNSPlatformMemCopy() to make sure it only touches the actual bytes that are valid.
2461 #define AssignDomainName(DST, SRC) mDNSPlatformMemCopy((SRC)->c, (DST)->c, DomainNameLength((SRC)))
2462 
2463 // Comparison functions
2464 extern mDNSBool SameDomainLabel(const mDNSu8 *a, const mDNSu8 *b);
2465 extern mDNSBool SameDomainName(const domainname *const d1, const domainname *const d2);
2466 extern mDNSBool IsLocalDomain(const domainname *d);     // returns true for domains that by default should be looked up using link-local multicast
2467 
2468 // Get total length of domain name, in native DNS format, including terminal root label
2469 //   (e.g. length of "com." is 5 (length byte, three data bytes, final zero)
2470 extern mDNSu16  DomainNameLength(const domainname *const name);
2471 
2472 // Append functions to append one or more labels to an existing native format domain name:
2473 //   AppendLiteralLabelString adds a single label from a literal C string, with no escape character interpretation.
2474 //   AppendDNSNameString      adds zero or more labels from a C string using conventional DNS dots-and-escaping interpretation
2475 //   AppendDomainLabel        adds a single label from a native format domainlabel
2476 //   AppendDomainName         adds zero or more labels from a native format domainname
2477 extern mDNSu8  *AppendLiteralLabelString(domainname *const name, const char *cstr);
2478 extern mDNSu8  *AppendDNSNameString     (domainname *const name, const char *cstr);
2479 extern mDNSu8  *AppendDomainLabel       (domainname *const name, const domainlabel *const label);
2480 extern mDNSu8  *AppendDomainName        (domainname *const name, const domainname *const append);
2481 
2482 // Convert from null-terminated string to native DNS format:
2483 //   The DomainLabel form makes a single label from a literal C string, with no escape character interpretation.
2484 //   The DomainName form makes native format domain name from a C string using conventional DNS interpretation:
2485 //     dots separate labels, and within each label, '\.' represents a literal dot, '\\' represents a literal
2486 //     backslash and backslash with three decimal digits (e.g. \000) represents an arbitrary byte value.
2487 extern mDNSBool MakeDomainLabelFromLiteralString(domainlabel *const label, const char *cstr);
2488 extern mDNSu8  *MakeDomainNameFromDNSNameString (domainname  *const name,  const char *cstr);
2489 
2490 // Convert native format domainlabel or domainname back to C string format
2491 // IMPORTANT:
2492 // When using ConvertDomainLabelToCString, the target buffer must be MAX_ESCAPED_DOMAIN_LABEL (254) bytes long
2493 // to guarantee there will be no buffer overrun. It is only safe to use a buffer shorter than this in rare cases
2494 // where the label is known to be constrained somehow (for example, if the label is known to be either "_tcp" or "_udp").
2495 // Similarly, when using ConvertDomainNameToCString, the target buffer must be MAX_ESCAPED_DOMAIN_NAME (1005) bytes long.
2496 // See definitions of MAX_ESCAPED_DOMAIN_LABEL and MAX_ESCAPED_DOMAIN_NAME for more detailed explanation.
2497 extern char    *ConvertDomainLabelToCString_withescape(const domainlabel *const name, char *cstr, char esc);
2498 #define         ConvertDomainLabelToCString_unescaped(D,C) ConvertDomainLabelToCString_withescape((D), (C), 0)
2499 #define         ConvertDomainLabelToCString(D,C)           ConvertDomainLabelToCString_withescape((D), (C), '\\')
2500 extern char    *ConvertDomainNameToCString_withescape(const domainname *const name, char *cstr, char esc);
2501 #define         ConvertDomainNameToCString_unescaped(D,C) ConvertDomainNameToCString_withescape((D), (C), 0)
2502 #define         ConvertDomainNameToCString(D,C)           ConvertDomainNameToCString_withescape((D), (C), '\\')
2503 
2504 extern void     ConvertUTF8PstringToRFC1034HostLabel(const mDNSu8 UTF8Name[], domainlabel *const hostlabel);
2505 
2506 extern mDNSu8  *ConstructServiceName(domainname *const fqdn, const domainlabel *name, const domainname *type, const domainname *const domain);
2507 extern mDNSBool DeconstructServiceName(const domainname *const fqdn, domainlabel *const name, domainname *const type, domainname *const domain);
2508 
2509 // Note: Some old functions have been replaced by more sensibly-named versions.
2510 // You can uncomment the hash-defines below if you don't want to have to change your source code right away.
2511 // When updating your code, note that (unlike the old versions) *all* the new routines take the target object
2512 // as their first parameter.
2513 //#define ConvertCStringToDomainName(SRC,DST)  MakeDomainNameFromDNSNameString((DST),(SRC))
2514 //#define ConvertCStringToDomainLabel(SRC,DST) MakeDomainLabelFromLiteralString((DST),(SRC))
2515 //#define AppendStringLabelToName(DST,SRC)     AppendLiteralLabelString((DST),(SRC))
2516 //#define AppendStringNameToName(DST,SRC)      AppendDNSNameString((DST),(SRC))
2517 //#define AppendDomainLabelToName(DST,SRC)     AppendDomainLabel((DST),(SRC))
2518 //#define AppendDomainNameToName(DST,SRC)      AppendDomainName((DST),(SRC))
2519 
2520 // ***************************************************************************
2521 #if 0
2522 #pragma mark - Other utility functions and macros
2523 #endif
2524 
2525 // mDNS_vsnprintf/snprintf return the number of characters written, excluding the final terminating null.
2526 // The output is always null-terminated: for example, if the output turns out to be exactly buflen long,
2527 // then the output will be truncated by one character to allow space for the terminating null.
2528 // Unlike standard C vsnprintf/snprintf, they return the number of characters *actually* written,
2529 // not the number of characters that *would* have been printed were buflen unlimited.
2530 extern mDNSu32 mDNS_vsnprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, va_list arg);
2531 extern mDNSu32 mDNS_snprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, ...) IS_A_PRINTF_STYLE_FUNCTION(3,4);
2532 extern mDNSu32 NumCacheRecordsForInterfaceID(const mDNS *const m, mDNSInterfaceID id);
2533 extern char *DNSTypeName(mDNSu16 rrtype);
2534 extern char *GetRRDisplayString_rdb(const ResourceRecord *rr, RDataBody *rd, char *buffer);
2535 #define RRDisplayString(m, rr) GetRRDisplayString_rdb(rr, &(rr)->rdata->u, (m)->MsgBuffer)
2536 #define ARDisplayString(m, rr) GetRRDisplayString_rdb(&(rr)->resrec, &(rr)->resrec.rdata->u, (m)->MsgBuffer)
2537 #define CRDisplayString(m, rr) GetRRDisplayString_rdb(&(rr)->resrec, &(rr)->resrec.rdata->u, (m)->MsgBuffer)
2538 extern mDNSBool mDNSSameAddress(const mDNSAddr *ip1, const mDNSAddr *ip2);
2539 extern void IncrementLabelSuffix(domainlabel *name, mDNSBool RichText);
2540 extern mDNSBool IsPrivateV4Addr(mDNSAddr *addr);  // returns true for RFC1918 private addresses
2541 
2542 #define mDNSSameIPv4Address(A,B) ((A).NotAnInteger == (B).NotAnInteger)
2543 #define mDNSSameIPv6Address(A,B) ((A).l[0] == (B).l[0] && (A).l[1] == (B).l[1] && (A).l[2] == (B).l[2] && (A).l[3] == (B).l[3])
2544 #define mDNSSameEthAddress(A,B)  ((A)->w[0] == (B)->w[0] && (A)->w[1] == (B)->w[1] && (A)->w[2] == (B)->w[2])
2545 
2546 #define mDNSIPv4AddressIsZero(A) mDNSSameIPv4Address((A), zerov4Addr)
2547 #define mDNSIPv6AddressIsZero(A) mDNSSameIPv6Address((A), zerov6Addr)
2548 
2549 #define mDNSIPv4AddressIsOnes(A) mDNSSameIPv4Address((A), onesIPv4Addr)
2550 #define mDNSIPv6AddressIsOnes(A) mDNSSameIPv6Address((A), onesIPv6Addr)
2551 
2552 #define mDNSAddressIsAllDNSLinkGroup(X) (                                                     \
2553 	((X)->type == mDNSAddrType_IPv4 && mDNSSameIPv4Address((X)->ip.v4, AllDNSLinkGroupv4)) || \
2554 	((X)->type == mDNSAddrType_IPv6 && mDNSSameIPv6Address((X)->ip.v6, AllDNSLinkGroupv6))    )
2555 
2556 #define mDNSAddressIsZero(X) (                                                \
2557 	((X)->type == mDNSAddrType_IPv4 && mDNSIPv4AddressIsZero((X)->ip.v4))  || \
2558 	((X)->type == mDNSAddrType_IPv6 && mDNSIPv6AddressIsZero((X)->ip.v6))     )
2559 
2560 #define mDNSAddressIsValidNonZero(X) (                                        \
2561 	((X)->type == mDNSAddrType_IPv4 && !mDNSIPv4AddressIsZero((X)->ip.v4)) || \
2562 	((X)->type == mDNSAddrType_IPv6 && !mDNSIPv6AddressIsZero((X)->ip.v6))    )
2563 
2564 #define mDNSAddressIsOnes(X) (                                                \
2565 	((X)->type == mDNSAddrType_IPv4 && mDNSIPv4AddressIsOnes((X)->ip.v4))  || \
2566 	((X)->type == mDNSAddrType_IPv6 && mDNSIPv6AddressIsOnes((X)->ip.v6))     )
2567 
2568 #define mDNSAddressIsValid(X) (                                                                                             \
2569 	((X)->type == mDNSAddrType_IPv4) ? !(mDNSIPv4AddressIsZero((X)->ip.v4) || mDNSIPv4AddressIsOnes((X)->ip.v4)) :          \
2570 	((X)->type == mDNSAddrType_IPv6) ? !(mDNSIPv6AddressIsZero((X)->ip.v6) || mDNSIPv6AddressIsOnes((X)->ip.v6)) : mDNSfalse)
2571 
2572 
2573 // ***************************************************************************
2574 #if 0
2575 #pragma mark - Authentication Support
2576 #endif
2577 
2578 #define HMAC_LEN    64
2579 #define HMAC_IPAD   0x36
2580 #define HMAC_OPAD   0x5c
2581 #define MD5_LEN     16
2582 
2583 // padded keys for inned/outer hash rounds
2584 typedef struct
2585 	{
2586 	mDNSu8 ipad[HMAC_LEN];
2587 	mDNSu8 opad[HMAC_LEN];
2588 	} HMAC_Key;
2589 
2590 // Internal data structure to maintain authentication information for an update domain
2591 typedef struct uDNS_AuthInfo
2592 	{
2593 	domainname zone;
2594 	domainname keyname;
2595 	HMAC_Key key;
2596 	struct uDNS_AuthInfo *next;
2597 	} uDNS_AuthInfo;
2598 
2599 // Unicast DNS and Dynamic Update specific Client Calls
2600 //
2601 // mDNS_SetSecretForZone tells the core to authenticate (via TSIG with an HMAC_MD5 hash of the shared secret)
2602 // when dynamically updating a given zone (and its subdomains).  The key used in authentication must be in
2603 // domain name format.  The shared secret must be a null-terminated base64 encoded string.  A minimum size of
2604 // 16 bytes (128 bits) is recommended for an MD5 hash as per RFC 2485.
2605 // Calling this routine multiple times for a zone replaces previously entered values.  Call with a NULL key
2606 // to dissable authentication for the zone.
2607 
2608 extern mStatus mDNS_SetSecretForZone(mDNS *m, const domainname *zone, const domainname *key, const char *sharedSecret);
2609 
2610 // Hostname/Unicast Interface Configuration
2611 
2612 // All hostnames advertised point to one IPv4 address and/or one IPv6 address, set via SetPrimaryInterfaceInfo.  Invoking this routine
2613 // updates all existing hostnames to point to the new address.
2614 
2615 // A hostname is added via AddDynDNSHostName, which points to the primary interface's v4 and/or v6 addresss
2616 
2617 // The status callback is invoked to convey success or failure codes - the callback should not modify the AuthRecord or free memory.
2618 // Added hostnames may be removed (deregistered) via mDNS_RemoveDynDNSHostName.
2619 
2620 // Host domains added prior to specification of the primary interface address and computer name will be deferred until
2621 // these values are initialized.
2622 
2623 // When routable V4 interfaces are added or removed, mDNS_UpdateLLQs should be called to re-estabish LLQs in case the
2624 // destination address for events (i.e. the route) has changed.  For performance reasons, the caller is responsible for
2625 // batching changes, e.g.  calling the routine only once if multiple interfaces are simultanously removed or added.
2626 
2627 // DNS servers used to resolve unicast queries are specified by mDNS_AddDNSServer, and may later be removed via mDNS_DeleteDNSServers.
2628 // For "split" DNS configurations, in which queries for different domains are sent to different servers (e.g. VPN and external),
2629 // a domain may be associated with a DNS server.  For standard configurations, specify the root label (".") or NULL.
2630 
2631 extern void mDNS_AddDynDNSHostName(mDNS *m, const domainname *fqdn, mDNSRecordCallback *StatusCallback, const void *StatusContext);
2632 extern void mDNS_RemoveDynDNSHostName(mDNS *m, const domainname *fqdn);
2633 extern void mDNS_SetPrimaryInterfaceInfo(mDNS *m, const mDNSAddr *v4addr,  const mDNSAddr *v6addr, const mDNSAddr *router);
2634 extern void mDNS_UpdateLLQs(mDNS *m);
2635 extern void mDNS_AddDNSServer(mDNS *const m, const mDNSAddr *dnsAddr, const domainname *domain);
2636 extern void mDNS_DeleteDNSServers(mDNS *const m);
2637 
2638 // Routines called by the core, exported by DNSDigest.c
2639 
2640 // Convert a base64 encoded key into a binary byte stream
2641 extern mDNSs32 DNSDigest_Base64ToBin(const char *src, mDNSu8 *target, mDNSu32 targsize);
2642 
2643 // Convert an arbitrary binary key (of any length) into an HMAC key (stored in AuthInfo struct)
2644 extern void DNSDigest_ConstructHMACKey(uDNS_AuthInfo *info, const mDNSu8 *key, mDNSu32 len);
2645 
2646 // sign a DNS message.  The message must be compete, with all values in network byte order.  end points to the end
2647 // of the message, and is modified by this routine.  numAdditionals is a pointer to the number of additional
2648 // records in HOST byte order, which is incremented upon successful completion of this routine.  The function returns
2649 // the new end pointer on success, and NULL on failure.
2650 extern mDNSu8 *DNSDigest_SignMessage(DNSMessage *msg, mDNSu8 **end, mDNSu16 *numAdditionals, uDNS_AuthInfo *info);
2651 
2652 // ***************************************************************************
2653 #if 0
2654 #pragma mark - PlatformSupport interface
2655 #endif
2656 
2657 // This section defines the interface to the Platform Support layer.
2658 // Normal client code should not use any of types defined here, or directly call any of the functions defined here.
2659 // The definitions are placed here because sometimes clients do use these calls indirectly, via other supported client operations.
2660 // For example, AssignDomainName is a macro defined using mDNSPlatformMemCopy()
2661 
2662 // Every platform support module must provide the following functions.
2663 // mDNSPlatformInit() typically opens a communication endpoint, and starts listening for mDNS packets.
2664 // When Setup is complete, the platform support layer calls mDNSCoreInitComplete().
2665 // mDNSPlatformSendUDP() sends one UDP packet
2666 // When a packet is received, the PlatformSupport code calls mDNSCoreReceive()
2667 // mDNSPlatformClose() tidies up on exit
2668 //
2669 // Note: mDNSPlatformMemAllocate/mDNSPlatformMemFree are only required for handling oversized resource records and unicast DNS.
2670 // If your target platform has a well-defined specialized application, and you know that all the records it uses
2671 // are InlineCacheRDSize or less, then you can just make a simple mDNSPlatformMemAllocate() stub that always returns
2672 // NULL. InlineCacheRDSize is a compile-time constant, which is set by default to 64. If you need to handle records
2673 // a little larger than this and you don't want to have to implement run-time allocation and freeing, then you
2674 // can raise the value of this constant to a suitable value (at the expense of increased memory usage).
2675 //
2676 // USE CAUTION WHEN CALLING mDNSPlatformRawTime: The m->timenow_adjust correction factor needs to be added
2677 // Generally speaking:
2678 // Code that's protected by the main mDNS lock should just use the m->timenow value
2679 // Code outside the main mDNS lock should use mDNS_TimeNow(m) to get properly adjusted time
2680 // In certain cases there may be reasons why it's necessary to get the time without taking the lock first
2681 // (e.g. inside the routines that are doing the locking and unlocking, where a call to get the lock would result in a
2682 // recursive loop); in these cases use mDNS_TimeNow_NoLock(m) to get mDNSPlatformRawTime with the proper correction factor added.
2683 //
2684 // mDNSPlatformUTC returns the time, in seconds, since Jan 1st 1970 UTC and is required for generating TSIG records
2685 
2686 extern mStatus  mDNSPlatformInit        (mDNS *const m);
2687 extern void     mDNSPlatformClose       (mDNS *const m);
2688 extern mStatus  mDNSPlatformSendUDP(const mDNS *const m, const void *const msg, const mDNSu8 *const end,
2689 mDNSInterfaceID InterfaceID, const mDNSAddr *dst, mDNSIPPort dstport);
2690 
2691 extern void     mDNSPlatformLock        (const mDNS *const m);
2692 extern void     mDNSPlatformUnlock      (const mDNS *const m);
2693 
2694 extern void     mDNSPlatformStrCopy     (const void *src,       void *dst);
2695 extern mDNSu32  mDNSPlatformStrLen      (const void *src);
2696 extern void     mDNSPlatformMemCopy     (const void *src,       void *dst, mDNSu32 len);
2697 extern mDNSBool mDNSPlatformMemSame     (const void *src, const void *dst, mDNSu32 len);
2698 extern void     mDNSPlatformMemZero     (                       void *dst, mDNSu32 len);
2699 extern void *   mDNSPlatformMemAllocate (mDNSu32 len);
2700 extern void     mDNSPlatformMemFree     (void *mem);
2701 extern mDNSu32  mDNSPlatformRandomSeed  (void);
2702 extern mStatus  mDNSPlatformTimeInit    (void);
2703 extern mDNSs32  mDNSPlatformRawTime     (void);
2704 extern mDNSs32  mDNSPlatformUTC         (void);
2705 #define mDNS_TimeNow_NoLock(m) (mDNSPlatformRawTime() + m->timenow_adjust)
2706 
2707 // Platform support modules should provide the following functions to map between opaque interface IDs
2708 // and interface indexes in order to support the DNS-SD API. If your target platform does not support
2709 // multiple interfaces and/or does not support the DNS-SD API, these functions can be empty.
2710 extern mDNSInterfaceID mDNSPlatformInterfaceIDfromInterfaceIndex(mDNS *const m, mDNSu32 index);
2711 extern mDNSu32 mDNSPlatformInterfaceIndexfromInterfaceID(mDNS *const m, mDNSInterfaceID id);
2712 
2713 // Every platform support module must provide the following functions if it is to support unicast DNS
2714 // and Dynamic Update.
2715 // All TCP socket operations implemented by the platform layer MUST NOT BLOCK.
2716 // mDNSPlatformTCPConnect initiates a TCP connection with a peer, adding the socket descriptor to the
2717 // main event loop.  The return value indicates whether the connection succeeded, failed, or is pending
2718 // (i.e. the call would block.)  On return, the descriptor parameter is set to point to the connected socket.
2719 // The TCPConnectionCallback is subsequently invoked when the connection
2720 // completes (in which case the ConnectionEstablished parameter is true), or data is available for
2721 // reading on the socket (indicated by the ConnectionEstablished parameter being false.)  If the connection
2722 // asynchronously fails, the TCPConnectionCallback should be invoked as usual, with the error being
2723 // returned in subsequent calls to PlatformReadTCP or PlatformWriteTCP.  (This allows for platforms
2724 // with limited asynchronous error detection capabilities.)  PlatformReadTCP and PlatformWriteTCP must
2725 // return the number of bytes read/written, 0 if the call would block, and -1 if an error.
2726 // PlatformTCPCloseConnection must close the connection to the peer and remove the descriptor from the
2727 // event loop.  CloseConnectin may be called at any time, including in a ConnectionCallback.
2728 
2729 typedef void (*TCPConnectionCallback)(int sd, void *context, mDNSBool ConnectionEstablished);
2730 extern mStatus mDNSPlatformTCPConnect(const mDNSAddr *dst, mDNSOpaque16 dstport, mDNSInterfaceID InterfaceID,
2731 										  TCPConnectionCallback callback, void *context, int *descriptor);
2732 extern void mDNSPlatformTCPCloseConnection(int sd);
2733 extern int mDNSPlatformReadTCP(int sd, void *buf, int buflen);
2734 extern int mDNSPlatformWriteTCP(int sd, const char *msg, int len);
2735 
2736 // Platforms that support unicast browsing and dynamic update registration for clients who do not specify a domain
2737 // in browse/registration calls must implement these routines to get the "default" browse/registration list.
2738 // The Get() functions must return a linked list of DNameListElem structs, allocated via mDNSPlatformMemAllocate.
2739 // Platforms may implement the Get() calls via the mDNS_CopyDNameList() helper routine.
2740 // Callers should free lists obtained via the Get() calls with th mDNS_FreeDNameList routine, provided by the core.
2741 
2742 typedef struct DNameListElem
2743 	{
2744 	domainname name;
2745 	struct DNameListElem *next;
2746 	} DNameListElem;
2747 
2748 extern DNameListElem *mDNSPlatformGetSearchDomainList(void);
2749 extern DNameListElem *mDNSPlatformGetRegDomainList(void);
2750 
2751 // Helper functions provided by the core
2752 extern DNameListElem *mDNS_CopyDNameList(const DNameListElem *orig);
2753 extern void mDNS_FreeDNameList(DNameListElem *list);
2754 
2755 #ifdef _LEGACY_NAT_TRAVERSAL_
2756 // Support for legacy NAT traversal protocols, implemented by the platform layer and callable by the core.
2757 
2758 #define DYN_PORT_MIN 49152 // ephemeral port range
2759 #define DYN_PORT_MAX 65535
2760 #define LEGACY_NATMAP_MAX_TRIES 4 // if our desired mapping is taken, how many times we try mapping to a random port
2761 
2762 extern mStatus LNT_GetPublicIP(mDNSOpaque32 *ip);
2763 extern mStatus LNT_MapPort(mDNSIPPort priv, mDNSIPPort pub, mDNSBool tcp);
2764 extern mStatus LNT_UnmapPort(mDNSIPPort PubPort, mDNSBool tcp);
2765 #endif // _LEGACY_NAT_TRAVERSAL_
2766 
2767 // The core mDNS code provides these functions, for the platform support code to call at appropriate times
2768 //
2769 // mDNS_SetFQDN() is called once on startup (typically from mDNSPlatformInit())
2770 // and then again on each subsequent change of the host name.
2771 //
2772 // mDNS_RegisterInterface() is used by the platform support layer to inform mDNSCore of what
2773 // physical and/or logical interfaces are available for sending and receiving packets.
2774 // Typically it is called on startup for each available interface, but register/deregister may be
2775 // called again later, on multiple occasions, to inform the core of interface configuration changes.
2776 // If set->Advertise is set non-zero, then mDNS_RegisterInterface() also registers the standard
2777 // resource records that should be associated with every publicised IP address/interface:
2778 // -- Name-to-address records (A/AAAA)
2779 // -- Address-to-name records (PTR)
2780 // -- Host information (HINFO)
2781 // IMPORTANT: The specified mDNSInterfaceID MUST NOT be 0, -1, or -2; these values have special meaning
2782 // mDNS_RegisterInterface does not result in the registration of global hostnames via dynamic update -
2783 // see mDNS_SetPrimaryInterfaceInfo, mDNS_AddDynDNSHostName, etc. for this purpose.
2784 // Note that the set may be deallocated immediately after it is deregistered via mDNS_DeegisterInterface.
2785 //
2786 // mDNS_RegisterDNS() is used by the platform support layer to provide the core with the addresses of
2787 // available domain name servers for unicast queries/updates.  RegisterDNS() should be called once for
2788 // each name server, typically at startup, or when a new name server becomes available.  DeregiterDNS()
2789 // must be called whenever a registered name server becomes unavailable.  DeregisterDNSList deregisters
2790 // all registered servers.  mDNS_DNSRegistered() returns true if one or more servers are registered in the core.
2791 //
2792 // mDNSCoreInitComplete() is called when the platform support layer is finished.
2793 // Typically this is at the end of mDNSPlatformInit(), but may be later
2794 // (on platforms like OT that allow asynchronous initialization of the networking stack).
2795 //
2796 // mDNSCoreReceive() is called when a UDP packet is received
2797 //
2798 // mDNSCoreMachineSleep() is called when the machine sleeps or wakes
2799 // (This refers to heavyweight laptop-style sleep/wake that disables network access,
2800 // not lightweight second-by-second CPU power management modes.)
2801 
2802 extern void     mDNS_SetFQDN(mDNS *const m);
2803 extern mStatus  mDNS_RegisterInterface  (mDNS *const m, NetworkInterfaceInfo *set, mDNSBool flapping);
2804 extern void     mDNS_DeregisterInterface(mDNS *const m, NetworkInterfaceInfo *set, mDNSBool flapping);
2805 extern void     mDNSCoreInitComplete(mDNS *const m, mStatus result);
2806 extern void     mDNSCoreReceive(mDNS *const m, void *const msg, const mDNSu8 *const end,
2807 								const mDNSAddr *const srcaddr, const mDNSIPPort srcport,
2808 								const mDNSAddr *const dstaddr, const mDNSIPPort dstport, const mDNSInterfaceID InterfaceID);
2809 extern void     mDNSCoreMachineSleep(mDNS *const m, mDNSBool wake);
2810 
2811 extern mDNSBool mDNSAddrIsDNSMulticast(const mDNSAddr *ip);
2812 
2813 // ***************************************************************************
2814 #if 0
2815 #pragma mark - Compile-Time assertion checks
2816 #endif
2817 
2818 // Some C compiler cleverness. We can make the compiler check certain things for
2819 // us, and report compile-time errors if anything is wrong. The usual way to do
2820 // this would be to use a run-time "if" statement, but then you don't find out
2821 // what's wrong until you run the software. This way, if the assertion condition
2822 // is false, the array size is negative, and the complier complains immediately.
2823 
2824 struct mDNS_CompileTimeAssertionChecks
2825 	{
2826 	// Check that the compiler generated our on-the-wire packet format structure definitions
2827 	// properly packed, without adding padding bytes to align fields on 32-bit or 64-bit boundaries.
2828 	char assert0[(sizeof(rdataSRV)         == 262                          ) ? 1 : -1];
2829 	char assert1[(sizeof(DNSMessageHeader) ==  12                          ) ? 1 : -1];
2830 	char assert2[(sizeof(DNSMessage)       ==  12+AbsoluteMaxDNSMessageData) ? 1 : -1];
2831 	char assert3[(sizeof(mDNSs8)           ==   1                          ) ? 1 : -1];
2832 	char assert4[(sizeof(mDNSu8)           ==   1                          ) ? 1 : -1];
2833 	char assert5[(sizeof(mDNSs16)          ==   2                          ) ? 1 : -1];
2834 	char assert6[(sizeof(mDNSu16)          ==   2                          ) ? 1 : -1];
2835 	char assert7[(sizeof(mDNSs32)          ==   4                          ) ? 1 : -1];
2836 	char assert8[(sizeof(mDNSu32)          ==   4                          ) ? 1 : -1];
2837 	char assert9[(sizeof(mDNSOpaque16)     ==   2                          ) ? 1 : -1];
2838 	char assertA[(sizeof(mDNSOpaque32)     ==   4                          ) ? 1 : -1];
2839 	char assertB[(sizeof(mDNSOpaque128)    ==  16                          ) ? 1 : -1];
2840 	char assertC[(sizeof(CacheRecord  )    >=  sizeof(CacheGroup)          ) ? 1 : -1];
2841 	char assertD[(sizeof(int)              >=  4                           ) ? 1 : -1];
2842 	};
2843 
2844 // ***************************************************************************
2845 
2846 #ifdef __cplusplus
2847 	}
2848 #endif
2849 
2850 #endif
2851