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    Change History (most recent first):
18
19Log: DNSCommon.h,v $
20Revision 1.73  2009/04/24 00:28:05  cheshire
21<rdar://problem/3476350> Return negative answers when host knows authoritatively that no answer exists
22Added definitions for RRTypeAnswersQuestionType/RRAssertsNonexistence/AnyTypeRecordAnswersQuestion
23
24Revision 1.72  2009/04/01 21:12:56  herscher
25<rdar://problem/5925472> Current Bonjour code does not compile on Windows
26
27Revision 1.71  2009/04/01 17:50:10  mcguire
28cleanup mDNSRandom
29
30Revision 1.70  2009/03/04 00:40:12  cheshire
31Updated DNS server error codes to be more consistent with definitions at
32<http://www.iana.org/assignments/dns-parameters>
33
34Revision 1.69  2008/11/26 20:57:37  cheshire
35For consistency with other similar macros, renamed mdnsIsDigit/mdnsIsLetter/mdnsValidHostChar
36to mDNSIsDigit/mDNSIsLetter/mDNSValidHostChar
37
38Revision 1.68  2008/11/14 21:56:31  cheshire
39Moved debugging routine ShowTaskSchedulingError() from daemon.c into DNSCommon.c
40
41Revision 1.67  2008/11/13 19:05:09  cheshire
42Added definition of LocateOptRR()
43
44Revision 1.66  2008/10/22 19:56:54  cheshire
45Removed unused SameRData() macro -- it duplicates the functionality of IdenticalSameNameRecord()
46
47Revision 1.65  2008/10/20 15:39:20  cheshire
48Group "#define PutResourceRecord ..." with related definitions
49
50Revision 1.64  2008/10/08 01:03:33  cheshire
51Change GetFirstActiveInterface() so the NetworkInterfaceInfo it returns is not "const"
52
53Revision 1.63  2008/09/23 02:30:07  cheshire
54Get rid of PutResourceRecordCappedTTL()
55
56Revision 1.62  2008/09/23 02:26:09  cheshire
57Don't need to export putEmptyResourceRecord (it's only used from DNSCommon.c)
58
59Revision 1.61  2008/08/13 00:47:53  mcguire
60Handle failures when packet logging
61
62Revision 1.60  2008/07/24 20:23:03  cheshire
63<rdar://problem/3988320> Should use randomized source ports and transaction IDs to avoid DNS cache poisoning
64
65Revision 1.59  2008/03/14 19:58:38  mcguire
66<rdar://problem/5500969> BTMM: Need ability to identify version of mDNSResponder client
67Make sure we add the record when sending LLQ refreshes
68
69Revision 1.58  2008/03/06 21:26:10  cheshire
70Moved duplicated STRINGIFY macro from individual C files to DNSCommon.h
71
72Revision 1.57  2007/12/13 20:20:17  cheshire
73Minor efficiency tweaks -- converted IdenticalResourceRecord, IdenticalSameNameRecord, and
74SameRData from functions to macros, which allows the code to be inlined (the compiler can't
75inline a function defined in a different compilation unit) and therefore optimized better.
76
77Revision 1.56  2007/12/13 00:13:03  cheshire
78Simplified RDataHashValue to take a single ResourceRecord pointer, instead of separate rdlength and RDataBody
79
80Revision 1.55  2007/12/13 00:09:28  cheshire
81For completeness added MX, AFSDB, RT, KX to list of RRTYPES that are considered to have a target domainname in their rdata
82
83Revision 1.54  2007/10/05 17:56:10  cheshire
84Move CountLabels and SkipLeadingLabels to DNSCommon.c so they're callable from other files
85
86Revision 1.53  2007/09/27 17:42:49  cheshire
87Fix naming: for consistency, "kDNSFlag1_RC" should be "kDNSFlag1_RC_Mask"
88
89Revision 1.52  2007/09/26 00:49:46  cheshire
90Improve packet logging to show sent and received packets,
91transport protocol (UDP/TCP/TLS) and source/destination address:port
92
93Revision 1.51  2007/09/21 21:12:36  cheshire
94<rdar://problem/5498009> BTMM: Need to log updates and query packet contents
95
96Revision 1.50  2007/09/20 01:12:06  cheshire
97Moved HashSlot(X) from mDNS.c to DNSCommon.h so it's usable in other files
98
99Revision 1.49  2007/08/30 00:31:20  cheshire
100Improve "locking failure" debugging messages to show function name using __func__ macro
101
102Revision 1.48  2007/05/25 00:25:44  cheshire
103<rdar://problem/5227737> Need to enhance putRData to output all current known types
104
105Revision 1.47  2007/05/01 21:46:31  cheshire
106Move GetLLQOptData/GetPktLease from uDNS.c into DNSCommon.c so that dnsextd can use them
107
108Revision 1.46  2007/04/22 20:18:10  cheshire
109Add comment about mDNSRandom()
110
111Revision 1.45  2007/04/22 06:02:02  cheshire
112<rdar://problem/4615977> Query should immediately return failure when no server
113
114Revision 1.44  2007/03/28 01:20:05  cheshire
115<rdar://problem/4883206> Improve/create logging for secure browse
116
117Revision 1.43  2007/03/20 17:07:15  cheshire
118Rename "struct uDNS_TCPSocket_struct" to "TCPSocket", "struct uDNS_UDPSocket_struct" to "UDPSocket"
119
120Revision 1.42  2007/03/10 03:26:44  cheshire
121<rdar://problem/4961667> uDNS: LLQ refresh response packet causes cached records to be removed from cache
122
123Revision 1.41  2007/01/18 23:18:17  cheshire
124Source code tidying: Delete extraneous white space
125
126Revision 1.40  2007/01/05 08:30:40  cheshire
127Trim excessive "Log" checkin history from before 2006
128(checkin history still available via "cvs log ..." of course)
129
130Revision 1.39  2007/01/04 21:45:20  cheshire
131Added mDNS_DropLockBeforeCallback/mDNS_ReclaimLockAfterCallback macros,
132to do additional lock sanity checking around callback invocations
133
134Revision 1.38  2006/12/22 20:59:49  cheshire
135<rdar://problem/4742742> Read *all* DNS keys from keychain,
136 not just key for the system-wide default registration domain
137
138Revision 1.37  2006/08/14 23:24:22  cheshire
139Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
140
141Revision 1.36  2006/07/05 22:56:07  cheshire
142<rdar://problem/4472014> Add Private DNS client functionality to mDNSResponder
143Update mDNSSendDNSMessage() to use uDNS_TCPSocket type instead of "int"
144
145Revision 1.35  2006/06/29 07:42:14  cheshire
146<rdar://problem/3922989> Performance: Remove unnecessary SameDomainName() checks
147
148Revision 1.34  2006/03/18 21:47:56  cheshire
149<rdar://problem/4073825> Improve logic for delaying packets after repeated interface transitions
150
151Revision 1.33  2006/03/10 21:51:41  cheshire
152<rdar://problem/4111464> After record update, old record sometimes remains in cache
153Split out SameRDataBody() into a separate routine so it can be called from other code
154
155*/
156
157#ifndef __DNSCOMMON_H_
158#define __DNSCOMMON_H_
159
160#include "mDNSEmbeddedAPI.h"
161
162#ifdef	__cplusplus
163	extern "C" {
164#endif
165
166//*************************************************************************************************************
167// Macros
168
169// Note: The C preprocessor stringify operator ('#') makes a string from its argument, without macro expansion
170// e.g. If "version" is #define'd to be "4", then STRINGIFY_AWE(version) will return the string "version", not "4"
171// To expand "version" to its value before making the string, use STRINGIFY(version) instead
172#define STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) #s
173#define STRINGIFY(s) STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s)
174
175// ***************************************************************************
176#if COMPILER_LIKES_PRAGMA_MARK
177#pragma mark - DNS Protocol Constants
178#endif
179
180typedef enum
181	{
182	kDNSFlag0_QR_Mask     = 0x80,		// Query or response?
183	kDNSFlag0_QR_Query    = 0x00,
184	kDNSFlag0_QR_Response = 0x80,
185
186	kDNSFlag0_OP_Mask     = 0x78,		// Operation type
187	kDNSFlag0_OP_StdQuery = 0x00,
188	kDNSFlag0_OP_Iquery   = 0x08,
189	kDNSFlag0_OP_Status   = 0x10,
190	kDNSFlag0_OP_Unused3  = 0x18,
191	kDNSFlag0_OP_Notify   = 0x20,
192	kDNSFlag0_OP_Update   = 0x28,
193
194	kDNSFlag0_QROP_Mask   = kDNSFlag0_QR_Mask | kDNSFlag0_OP_Mask,
195
196	kDNSFlag0_AA          = 0x04,		// Authoritative Answer?
197	kDNSFlag0_TC          = 0x02,		// Truncated?
198	kDNSFlag0_RD          = 0x01,		// Recursion Desired?
199	kDNSFlag1_RA          = 0x80,		// Recursion Available?
200
201	kDNSFlag1_Zero        = 0x40,		// Reserved; must be zero
202	kDNSFlag1_AD          = 0x20,		// Authentic Data [RFC 2535]
203	kDNSFlag1_CD          = 0x10,		// Checking Disabled [RFC 2535]
204
205	kDNSFlag1_RC_Mask     = 0x0F,		// Response code
206	kDNSFlag1_RC_NoErr    = 0x00,
207	kDNSFlag1_RC_FormErr  = 0x01,
208	kDNSFlag1_RC_ServFail = 0x02,
209	kDNSFlag1_RC_NXDomain = 0x03,
210	kDNSFlag1_RC_NotImpl  = 0x04,
211	kDNSFlag1_RC_Refused  = 0x05,
212	kDNSFlag1_RC_YXDomain = 0x06,
213	kDNSFlag1_RC_YXRRSet  = 0x07,
214	kDNSFlag1_RC_NXRRSet  = 0x08,
215	kDNSFlag1_RC_NotAuth  = 0x09,
216	kDNSFlag1_RC_NotZone  = 0x0A
217	} DNS_Flags;
218
219typedef enum
220	{
221	TSIG_ErrBadSig  = 16,
222	TSIG_ErrBadKey  = 17,
223	TSIG_ErrBadTime = 18
224	} TSIG_ErrorCode;
225
226// ***************************************************************************
227#if COMPILER_LIKES_PRAGMA_MARK
228#pragma mark -
229#pragma mark - General Utility Functions
230#endif
231
232extern NetworkInterfaceInfo *GetFirstActiveInterface(NetworkInterfaceInfo *intf);
233extern mDNSInterfaceID GetNextActiveInterfaceID(const NetworkInterfaceInfo *intf);
234
235extern mDNSu32 mDNSRandom(mDNSu32 max);		// Returns pseudo-random result from zero to max inclusive
236
237// ***************************************************************************
238#if COMPILER_LIKES_PRAGMA_MARK
239#pragma mark -
240#pragma mark - Domain Name Utility Functions
241#endif
242
243#define mDNSIsDigit(X)     ((X) >= '0' && (X) <= '9')
244#define mDNSIsUpperCase(X) ((X) >= 'A' && (X) <= 'Z')
245#define mDNSIsLowerCase(X) ((X) >= 'a' && (X) <= 'z')
246#define mDNSIsLetter(X)    (mDNSIsUpperCase(X) || mDNSIsLowerCase(X))
247
248#define mDNSValidHostChar(X, notfirst, notlast) (mDNSIsLetter(X) || mDNSIsDigit(X) || ((notfirst) && (notlast) && (X) == '-') )
249
250extern mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent);
251extern int CountLabels(const domainname *d);
252extern const domainname *SkipLeadingLabels(const domainname *d, int skip);
253
254extern mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max);
255extern mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText);
256extern mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText);
257extern void AppendLabelSuffix(domainlabel *name, mDNSu32 val, mDNSBool RichText);
258#define ValidateDomainName(N) (DomainNameLength(N) <= MAX_DOMAIN_NAME)
259
260// ***************************************************************************
261#if COMPILER_LIKES_PRAGMA_MARK
262#pragma mark -
263#pragma mark - Resource Record Utility Functions
264#endif
265
266// IdenticalResourceRecord returns true if two resources records have
267// the same name, type, class, and identical rdata (InterfaceID and TTL may differ)
268
269// IdenticalSameNameRecord is the same, except it skips the expensive SameDomainName() check,
270// which is at its most expensive and least useful in cases where we know in advance that the names match
271
272// Note: The dominant use of IdenticalResourceRecord is from ProcessQuery(), handling known-answer lists. In this case
273// it's common to have a whole bunch or records with exactly the same name (e.g. "_http._tcp.local") but different RDATA.
274// The SameDomainName() check is expensive when the names match, and in this case *all* the names match, so we
275// used to waste a lot of CPU time verifying that the names match, only then to find that the RDATA is different.
276// We observed mDNSResponder spending 30% of its total CPU time on this single task alone.
277// By swapping the checks so that we check the RDATA first, we can quickly detect when it's different
278// (99% of the time) and then bail out before we waste time on the expensive SameDomainName() check.
279
280#define IdenticalResourceRecord(r1,r2) ( \
281	(r1)->rrtype    == (r2)->rrtype      && \
282	(r1)->rrclass   == (r2)->rrclass     && \
283	(r1)->namehash  == (r2)->namehash    && \
284	(r1)->rdlength  == (r2)->rdlength    && \
285	(r1)->rdatahash == (r2)->rdatahash   && \
286	SameRDataBody((r1), &(r2)->rdata->u) && \
287	SameDomainName((r1)->name, (r2)->name))
288
289#define IdenticalSameNameRecord(r1,r2) ( \
290	(r1)->rrtype    == (r2)->rrtype      && \
291	(r1)->rrclass   == (r2)->rrclass     && \
292	(r1)->rdlength  == (r2)->rdlength    && \
293	(r1)->rdatahash == (r2)->rdatahash   && \
294	SameRDataBody((r1), &(r2)->rdata->u))
295
296// A given RRType answers a QuestionType if RRType is CNAME, or types match, or QuestionType is ANY,
297// or the RRType is NSEC and positively asserts the nonexistence of the type being requested
298#define RRTypeAnswersQuestionType(R,T) ((R)->rrtype == kDNSType_CNAME || (R)->rrtype == (T) || (T) == kDNSQType_ANY || RRAssertsNonexistence((R),(T)))
299#define RRAssertsNonexistence(R,T) ((R)->rrtype == kDNSType_NSEC && (T) < kDNSQType_ANY && !((R)->rdata->u.nsec.bitmap[(T)>>3] & (128 >> ((T)&7))))
300
301extern mDNSu32 RDataHashValue(const ResourceRecord *const rr);
302extern mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2);
303extern mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q);
304extern mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q);
305extern mDNSBool AnyTypeRecordAnswersQuestion (const ResourceRecord *const rr, const DNSQuestion *const q);
306extern mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate);
307extern mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd);
308
309#define GetRRDomainNameTarget(RR) (                                                                          \
310	((RR)->rrtype == kDNSType_NS || (RR)->rrtype == kDNSType_CNAME || (RR)->rrtype == kDNSType_PTR || (RR)->rrtype == kDNSType_DNAME) ? &(RR)->rdata->u.name        : \
311	((RR)->rrtype == kDNSType_MX || (RR)->rrtype == kDNSType_AFSDB || (RR)->rrtype == kDNSType_RT  || (RR)->rrtype == kDNSType_KX   ) ? &(RR)->rdata->u.mx.exchange : \
312	((RR)->rrtype == kDNSType_SRV                                  ) ? &(RR)->rdata->u.srv.target : mDNSNULL )
313
314#define LocalRecordReady(X) ((X)->resrec.RecordType != kDNSRecordTypeUnique && (X)->resrec.RecordType != kDNSRecordTypeDeregistering)
315
316// ***************************************************************************
317#if COMPILER_LIKES_PRAGMA_MARK
318#pragma mark -
319#pragma mark - DNS Message Creation Functions
320#endif
321
322extern void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags);
323extern const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname);
324extern mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name);
325extern mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr);
326
327// If we have a single large record to put in the packet, then we allow the packet to be up to 9K bytes,
328// but in the normal case we try to keep the packets below 1500 to avoid IP fragmentation on standard Ethernet
329extern mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit);
330
331#define PutResourceRecordTTL(msg, ptr, count, rr, ttl) \
332	PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), \
333	((msg)->h.numAnswers || (msg)->h.numAuthorities || (msg)->h.numAdditionals) ? (msg)->data + NormalMaxDNSMessageData : (msg)->data + AbsoluteMaxDNSMessageData)
334#define PutResourceRecordTTLJumbo(msg, ptr, count, rr, ttl) \
335	PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), (msg)->data + AbsoluteMaxDNSMessageData)
336#define PutResourceRecord(MSG, P, C, RR) PutResourceRecordTTL((MSG), (P), (C), (RR), (RR)->rroriginalttl)
337
338extern mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass);
339extern mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass);
340extern mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *msg, mDNSu8 *ptr, mDNSu8 *end);
341extern mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr);
342extern  mDNSu8 *putDeleteRRSet(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype);
343extern mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name);
344extern mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease);
345
346extern mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *end, DomainAuthInfo *authInfo);
347
348// ***************************************************************************
349#if COMPILER_LIKES_PRAGMA_MARK
350#pragma mark -
351#pragma mark - DNS Message Parsing Functions
352#endif
353
354#define HashSlot(X) (DomainNameHashValue(X) % CACHE_HASH_SLOTS)
355extern mDNSu32 DomainNameHashValue(const domainname *const name);
356extern void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength);
357extern const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end);
358extern const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end,
359	domainname *const name);
360extern const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end);
361extern const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage * const msg, const mDNSu8 *ptr,
362    const mDNSu8 * end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *largecr);
363extern const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end);
364extern const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID,
365	DNSQuestion *question);
366extern const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end);
367extern const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end);
368extern const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end);
369extern const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize);
370extern const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end);
371extern mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end);
372extern void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport,
373	const mDNSAddr *srcaddr, mDNSIPPort srcport,
374	const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end);
375
376// ***************************************************************************
377#if COMPILER_LIKES_PRAGMA_MARK
378#pragma mark -
379#pragma mark - Packet Sending Functions
380#endif
381
382extern mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end,
383	mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo);
384
385// ***************************************************************************
386#if COMPILER_LIKES_PRAGMA_MARK
387#pragma mark -
388#pragma mark - RR List Management & Task Management
389#endif
390
391extern void ShowTaskSchedulingError(mDNS *const m);
392extern void mDNS_Lock_(mDNS *const m);
393extern void mDNS_Unlock_(mDNS *const m);
394
395#if defined(_WIN32)
396 #define __func__ __FUNCTION__
397#endif
398
399#define mDNS_Lock(X) do { \
400	if ((X)->mDNS_busy != (X)->mDNS_reentrancy) LogMsg("%s: mDNS_Lock locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, (X)->mDNS_busy, (X)->mDNS_reentrancy); \
401	mDNS_Lock_(X); } while (0)
402
403#define mDNS_Unlock(X) do { mDNS_Unlock_(X); \
404	if ((X)->mDNS_busy != (X)->mDNS_reentrancy) LogMsg("%s: mDNS_Unlock locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, (X)->mDNS_busy, (X)->mDNS_reentrancy); \
405	} while (0)
406
407#define mDNS_DropLockBeforeCallback() do { m->mDNS_reentrancy++; \
408	if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Locking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \
409	} while (0)
410
411#define mDNS_ReclaimLockAfterCallback() do { \
412	if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Unlocking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \
413	m->mDNS_reentrancy--; } while (0)
414
415#ifdef	__cplusplus
416	}
417#endif
418
419#endif // __DNSCOMMON_H_
420