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#ifndef __DNSCOMMON_H_ 19#define __DNSCOMMON_H_ 20 21#include "mDNSEmbeddedAPI.h" 22 23#ifdef __cplusplus 24 extern "C" { 25#endif 26 27//************************************************************************************************************* 28// Macros 29 30// Note: The C preprocessor stringify operator ('#') makes a string from its argument, without macro expansion 31// e.g. If "version" is #define'd to be "4", then STRINGIFY_AWE(version) will return the string "version", not "4" 32// To expand "version" to its value before making the string, use STRINGIFY(version) instead 33#define STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) #s 34#define STRINGIFY(s) STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) 35 36// *************************************************************************** 37#if COMPILER_LIKES_PRAGMA_MARK 38#pragma mark - DNS Protocol Constants 39#endif 40 41typedef enum 42 { 43 kDNSFlag0_QR_Mask = 0x80, // Query or response? 44 kDNSFlag0_QR_Query = 0x00, 45 kDNSFlag0_QR_Response = 0x80, 46 47 kDNSFlag0_OP_Mask = 0x78, // Operation type 48 kDNSFlag0_OP_StdQuery = 0x00, 49 kDNSFlag0_OP_Iquery = 0x08, 50 kDNSFlag0_OP_Status = 0x10, 51 kDNSFlag0_OP_Unused3 = 0x18, 52 kDNSFlag0_OP_Notify = 0x20, 53 kDNSFlag0_OP_Update = 0x28, 54 55 kDNSFlag0_QROP_Mask = kDNSFlag0_QR_Mask | kDNSFlag0_OP_Mask, 56 57 kDNSFlag0_AA = 0x04, // Authoritative Answer? 58 kDNSFlag0_TC = 0x02, // Truncated? 59 kDNSFlag0_RD = 0x01, // Recursion Desired? 60 kDNSFlag1_RA = 0x80, // Recursion Available? 61 62 kDNSFlag1_Zero = 0x40, // Reserved; must be zero 63 kDNSFlag1_AD = 0x20, // Authentic Data [RFC 2535] 64 kDNSFlag1_CD = 0x10, // Checking Disabled [RFC 2535] 65 66 kDNSFlag1_RC_Mask = 0x0F, // Response code 67 kDNSFlag1_RC_NoErr = 0x00, 68 kDNSFlag1_RC_FormErr = 0x01, 69 kDNSFlag1_RC_ServFail = 0x02, 70 kDNSFlag1_RC_NXDomain = 0x03, 71 kDNSFlag1_RC_NotImpl = 0x04, 72 kDNSFlag1_RC_Refused = 0x05, 73 kDNSFlag1_RC_YXDomain = 0x06, 74 kDNSFlag1_RC_YXRRSet = 0x07, 75 kDNSFlag1_RC_NXRRSet = 0x08, 76 kDNSFlag1_RC_NotAuth = 0x09, 77 kDNSFlag1_RC_NotZone = 0x0A 78 } DNS_Flags; 79 80typedef enum 81 { 82 TSIG_ErrBadSig = 16, 83 TSIG_ErrBadKey = 17, 84 TSIG_ErrBadTime = 18 85 } TSIG_ErrorCode; 86 87// *************************************************************************** 88#if COMPILER_LIKES_PRAGMA_MARK 89#pragma mark - 90#pragma mark - General Utility Functions 91#endif 92 93extern NetworkInterfaceInfo *GetFirstActiveInterface(NetworkInterfaceInfo *intf); 94extern mDNSInterfaceID GetNextActiveInterfaceID(const NetworkInterfaceInfo *intf); 95 96extern mDNSu32 mDNSRandom(mDNSu32 max); // Returns pseudo-random result from zero to max inclusive 97 98// *************************************************************************** 99#if COMPILER_LIKES_PRAGMA_MARK 100#pragma mark - 101#pragma mark - Domain Name Utility Functions 102#endif 103 104#define mDNSIsDigit(X) ((X) >= '0' && (X) <= '9') 105#define mDNSIsUpperCase(X) ((X) >= 'A' && (X) <= 'Z') 106#define mDNSIsLowerCase(X) ((X) >= 'a' && (X) <= 'z') 107#define mDNSIsLetter(X) (mDNSIsUpperCase(X) || mDNSIsLowerCase(X)) 108 109#define mDNSValidHostChar(X, notfirst, notlast) (mDNSIsLetter(X) || mDNSIsDigit(X) || ((notfirst) && (notlast) && (X) == '-') ) 110 111extern mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent); 112extern int CountLabels(const domainname *d); 113extern const domainname *SkipLeadingLabels(const domainname *d, int skip); 114 115extern mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max); 116extern mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText); 117extern mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText); 118extern void AppendLabelSuffix(domainlabel *const name, mDNSu32 val, const mDNSBool RichText); 119#define ValidateDomainName(N) (DomainNameLength(N) <= MAX_DOMAIN_NAME) 120 121// *************************************************************************** 122#if COMPILER_LIKES_PRAGMA_MARK 123#pragma mark - 124#pragma mark - Resource Record Utility Functions 125#endif 126 127// IdenticalResourceRecord returns true if two resources records have 128// the same name, type, class, and identical rdata (InterfaceID and TTL may differ) 129 130// IdenticalSameNameRecord is the same, except it skips the expensive SameDomainName() check, 131// which is at its most expensive and least useful in cases where we know in advance that the names match 132 133// Note: The dominant use of IdenticalResourceRecord is from ProcessQuery(), handling known-answer lists. In this case 134// it's common to have a whole bunch or records with exactly the same name (e.g. "_http._tcp.local") but different RDATA. 135// The SameDomainName() check is expensive when the names match, and in this case *all* the names match, so we 136// used to waste a lot of CPU time verifying that the names match, only then to find that the RDATA is different. 137// We observed mDNSResponder spending 30% of its total CPU time on this single task alone. 138// By swapping the checks so that we check the RDATA first, we can quickly detect when it's different 139// (99% of the time) and then bail out before we waste time on the expensive SameDomainName() check. 140 141#define IdenticalResourceRecord(r1,r2) ( \ 142 (r1)->rrtype == (r2)->rrtype && \ 143 (r1)->rrclass == (r2)->rrclass && \ 144 (r1)->namehash == (r2)->namehash && \ 145 (r1)->rdlength == (r2)->rdlength && \ 146 (r1)->rdatahash == (r2)->rdatahash && \ 147 SameRDataBody((r1), &(r2)->rdata->u, SameDomainName) && \ 148 SameDomainName((r1)->name, (r2)->name)) 149 150#define IdenticalSameNameRecord(r1,r2) ( \ 151 (r1)->rrtype == (r2)->rrtype && \ 152 (r1)->rrclass == (r2)->rrclass && \ 153 (r1)->rdlength == (r2)->rdlength && \ 154 (r1)->rdatahash == (r2)->rdatahash && \ 155 SameRDataBody((r1), &(r2)->rdata->u, SameDomainName)) 156 157// A given RRType answers a QuestionType if RRType is CNAME, or types match, or QuestionType is ANY, 158// or the RRType is NSEC and positively asserts the nonexistence of the type being requested 159#define RRTypeAnswersQuestionType(R,Q) ((R)->rrtype == kDNSType_CNAME || (R)->rrtype == (Q) || (Q) == kDNSQType_ANY || RRAssertsNonexistence((R),(Q))) 160#define RRAssertsNonexistence(R,T) ((R)->rrtype == kDNSType_NSEC && (T) < kDNSQType_ANY && !((R)->rdata->u.nsec.bitmap[(T)>>3] & (128 >> ((T)&7)))) 161 162extern mDNSu32 RDataHashValue(const ResourceRecord *const rr); 163extern mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2, DomainNameComparisonFn *samename); 164extern mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q); 165extern mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q); 166extern mDNSBool AnyTypeRecordAnswersQuestion (const ResourceRecord *const rr, const DNSQuestion *const q); 167extern mDNSBool ResourceRecordAnswersUnicastResponse(const ResourceRecord *const rr, const DNSQuestion *const q); 168extern mDNSBool LocalOnlyRecordAnswersQuestion(AuthRecord *const rr, const DNSQuestion *const q); 169extern mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate); 170extern mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd); 171 172#define GetRRDomainNameTarget(RR) ( \ 173 ((RR)->rrtype == kDNSType_NS || (RR)->rrtype == kDNSType_CNAME || (RR)->rrtype == kDNSType_PTR || (RR)->rrtype == kDNSType_DNAME) ? &(RR)->rdata->u.name : \ 174 ((RR)->rrtype == kDNSType_MX || (RR)->rrtype == kDNSType_AFSDB || (RR)->rrtype == kDNSType_RT || (RR)->rrtype == kDNSType_KX ) ? &(RR)->rdata->u.mx.exchange : \ 175 ((RR)->rrtype == kDNSType_SRV ) ? &(RR)->rdata->u.srv.target : mDNSNULL ) 176 177#define LocalRecordReady(X) ((X)->resrec.RecordType != kDNSRecordTypeUnique) 178 179// *************************************************************************** 180#if COMPILER_LIKES_PRAGMA_MARK 181#pragma mark - 182#pragma mark - DNS Message Creation Functions 183#endif 184 185extern void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags); 186extern const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname); 187extern mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name); 188extern mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr); 189 190// If we have a single large record to put in the packet, then we allow the packet to be up to 9K bytes, 191// but in the normal case we try to keep the packets below 1500 to avoid IP fragmentation on standard Ethernet 192 193#define AllowedRRSpace(msg) (((msg)->h.numAnswers || (msg)->h.numAuthorities || (msg)->h.numAdditionals) ? NormalMaxDNSMessageData : AbsoluteMaxDNSMessageData) 194 195extern mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit); 196 197#define PutResourceRecordTTL(msg, ptr, count, rr, ttl) \ 198 PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), (msg)->data + AllowedRRSpace(msg)) 199 200#define PutResourceRecordTTLJumbo(msg, ptr, count, rr, ttl) \ 201 PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), (msg)->data + AbsoluteMaxDNSMessageData) 202 203#define PutResourceRecord(MSG, P, C, RR) PutResourceRecordTTL((MSG), (P), (C), (RR), (RR)->rroriginalttl) 204 205// The PutRR_OS variants assume a local variable 'm', put build the packet at m->omsg, 206// and assume a local variable 'OwnerRecordSpace' indicating how many bytes (if any) to reserve to add an OWNER option at the end 207#define PutRR_OS_TTL(ptr, count, rr, ttl) \ 208 PutResourceRecordTTLWithLimit(&m->omsg, (ptr), (count), (rr), (ttl), m->omsg.data + AllowedRRSpace(&m->omsg) - OwnerRecordSpace) 209 210#define PutRR_OS(P, C, RR) PutRR_OS_TTL((P), (C), (RR), (RR)->rroriginalttl) 211 212extern mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass); 213extern mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass); 214extern mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *const msg, mDNSu8 *const ptr, mDNSu8 *const end); 215extern mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr); 216extern mDNSu8 *putDeletionRecordWithLimit(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr, mDNSu8 *limit); 217extern mDNSu8 *putDeleteRRSetWithLimit(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype, mDNSu8 *limit); 218extern mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name); 219extern mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease); 220extern mDNSu8 *putUpdateLeaseWithLimit(DNSMessage *msg, mDNSu8 *ptr, mDNSu32 lease, mDNSu8 *limit); 221 222extern mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *ptr, DomainAuthInfo *authInfo, mDNSu8 *limit); 223 224// *************************************************************************** 225#if COMPILER_LIKES_PRAGMA_MARK 226#pragma mark - 227#pragma mark - DNS Message Parsing Functions 228#endif 229 230#define AuthHashSlot(X) (DomainNameHashValue(X) % AUTH_HASH_SLOTS) 231#define HashSlot(X) (DomainNameHashValue(X) % CACHE_HASH_SLOTS) 232extern mDNSu32 DomainNameHashValue(const domainname *const name); 233extern void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength); 234extern const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end); 235extern const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, 236 domainname *const name); 237extern const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end); 238extern const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage * const msg, const mDNSu8 *ptr, 239 const mDNSu8 * end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *const largecr); 240extern const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end); 241extern const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID, 242 DNSQuestion *question); 243extern const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end); 244extern const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end); 245extern const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end); 246extern const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize); 247extern const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end); 248extern mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end); 249extern void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport, 250 const mDNSAddr *srcaddr, mDNSIPPort srcport, 251 const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end); 252 253// *************************************************************************** 254#if COMPILER_LIKES_PRAGMA_MARK 255#pragma mark - 256#pragma mark - Packet Sending Functions 257#endif 258 259extern mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end, 260 mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo); 261 262// *************************************************************************** 263#if COMPILER_LIKES_PRAGMA_MARK 264#pragma mark - 265#pragma mark - RR List Management & Task Management 266#endif 267 268extern void ShowTaskSchedulingError(mDNS *const m); 269extern void mDNS_Lock_(mDNS *const m, const char * const functionname); 270extern void mDNS_Unlock_(mDNS *const m, const char * const functionname); 271 272#if defined(_WIN32) 273 #define __func__ __FUNCTION__ 274#endif 275 276#define mDNS_Lock(X) mDNS_Lock_((X), __func__) 277 278#define mDNS_Unlock(X) mDNS_Unlock_((X), __func__) 279 280#define mDNS_DropLockBeforeCallback() do { m->mDNS_reentrancy++; \ 281 if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Locking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \ 282 } while (0) 283 284#define mDNS_ReclaimLockAfterCallback() do { \ 285 if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Unlocking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \ 286 m->mDNS_reentrancy--; } while (0) 287 288#ifdef __cplusplus 289 } 290#endif 291 292#endif // __DNSCOMMON_H_ 293