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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 // Set mDNS_InstantiateInlines to tell mDNSEmbeddedAPI.h to instantiate inline functions, if necessary
19 #define mDNS_InstantiateInlines 1
20 #include "DNSCommon.h"
21
22 // Disable certain benign warnings with Microsoft compilers
23 #if (defined(_MSC_VER))
24 // Disable "conditional expression is constant" warning for debug macros.
25 // Otherwise, this generates warnings for the perfectly natural construct "while(1)"
26 // If someone knows a variant way of writing "while(1)" that doesn't generate warning messages, please let us know
27 #pragma warning(disable:4127)
28 // Disable "array is too small to include a terminating null character" warning
29 // -- domain labels have an initial length byte, not a terminating null character
30 #pragma warning(disable:4295)
31 #endif
32
33 // ***************************************************************************
34 #if COMPILER_LIKES_PRAGMA_MARK
35 #pragma mark - Program Constants
36 #endif
37
38 mDNSexport const mDNSInterfaceID mDNSInterface_Any = 0;
39 mDNSexport const mDNSInterfaceID mDNSInterfaceMark = (mDNSInterfaceID)-1;
40 mDNSexport const mDNSInterfaceID mDNSInterface_LocalOnly = (mDNSInterfaceID)-2;
41 mDNSexport const mDNSInterfaceID mDNSInterface_Unicast = (mDNSInterfaceID)-3;
42 mDNSexport const mDNSInterfaceID mDNSInterface_P2P = (mDNSInterfaceID)-4;
43
44 // Note: Microsoft's proposed "Link Local Multicast Name Resolution Protocol" (LLMNR) is essentially a limited version of
45 // Multicast DNS, using the same packet formats, naming syntax, and record types as Multicast DNS, but on a different UDP
46 // port and multicast address, which means it won't interoperate with the existing installed base of Multicast DNS responders.
47 // LLMNR uses IPv4 multicast address 224.0.0.252, IPv6 multicast address FF02::0001:0003, and UDP port 5355.
48 // Uncomment the appropriate lines below to build a special Multicast DNS responder for testing interoperability
49 // with Microsoft's LLMNR client code.
50
51 #define DiscardPortAsNumber 9
52 #define SSHPortAsNumber 22
53 #define UnicastDNSPortAsNumber 53
54 #define SSDPPortAsNumber 1900
55 #define IPSECPortAsNumber 4500
56 #define NSIPCPortAsNumber 5030 // Port used for dnsextd to talk to local nameserver bound to loopback
57 #define NATPMPAnnouncementPortAsNumber 5350
58 #define NATPMPPortAsNumber 5351
59 #define DNSEXTPortAsNumber 5352 // Port used for end-to-end DNS operations like LLQ, Updates with Leases, etc.
60 #define MulticastDNSPortAsNumber 5353
61 #define LoopbackIPCPortAsNumber 5354
62 //#define MulticastDNSPortAsNumber 5355 // LLMNR
63 #define PrivateDNSPortAsNumber 5533
64
65 mDNSexport const mDNSIPPort DiscardPort = { { DiscardPortAsNumber >> 8, DiscardPortAsNumber & 0xFF } };
66 mDNSexport const mDNSIPPort SSHPort = { { SSHPortAsNumber >> 8, SSHPortAsNumber & 0xFF } };
67 mDNSexport const mDNSIPPort UnicastDNSPort = { { UnicastDNSPortAsNumber >> 8, UnicastDNSPortAsNumber & 0xFF } };
68 mDNSexport const mDNSIPPort SSDPPort = { { SSDPPortAsNumber >> 8, SSDPPortAsNumber & 0xFF } };
69 mDNSexport const mDNSIPPort IPSECPort = { { IPSECPortAsNumber >> 8, IPSECPortAsNumber & 0xFF } };
70 mDNSexport const mDNSIPPort NSIPCPort = { { NSIPCPortAsNumber >> 8, NSIPCPortAsNumber & 0xFF } };
71 mDNSexport const mDNSIPPort NATPMPAnnouncementPort = { { NATPMPAnnouncementPortAsNumber >> 8, NATPMPAnnouncementPortAsNumber & 0xFF } };
72 mDNSexport const mDNSIPPort NATPMPPort = { { NATPMPPortAsNumber >> 8, NATPMPPortAsNumber & 0xFF } };
73 mDNSexport const mDNSIPPort DNSEXTPort = { { DNSEXTPortAsNumber >> 8, DNSEXTPortAsNumber & 0xFF } };
74 mDNSexport const mDNSIPPort MulticastDNSPort = { { MulticastDNSPortAsNumber >> 8, MulticastDNSPortAsNumber & 0xFF } };
75 mDNSexport const mDNSIPPort LoopbackIPCPort = { { LoopbackIPCPortAsNumber >> 8, LoopbackIPCPortAsNumber & 0xFF } };
76 mDNSexport const mDNSIPPort PrivateDNSPort = { { PrivateDNSPortAsNumber >> 8, PrivateDNSPortAsNumber & 0xFF } };
77
78 mDNSexport const OwnerOptData zeroOwner = { 0, 0, { { 0 } }, { { 0 } }, { { 0 } } };
79
80 mDNSexport const mDNSIPPort zeroIPPort = { { 0 } };
81 mDNSexport const mDNSv4Addr zerov4Addr = { { 0 } };
82 mDNSexport const mDNSv6Addr zerov6Addr = { { 0 } };
83 mDNSexport const mDNSEthAddr zeroEthAddr = { { 0 } };
84 mDNSexport const mDNSv4Addr onesIPv4Addr = { { 255, 255, 255, 255 } };
85 mDNSexport const mDNSv6Addr onesIPv6Addr = { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 } };
86 mDNSexport const mDNSEthAddr onesEthAddr = { { 255, 255, 255, 255, 255, 255 } };
87 mDNSexport const mDNSAddr zeroAddr = { mDNSAddrType_None, {{{ 0 }}} };
88
89 mDNSexport const mDNSv4Addr AllDNSAdminGroup = { { 239, 255, 255, 251 } };
90 mDNSexport const mDNSv4Addr AllHosts_v4 = { { 224, 0, 0, 1 } }; // For NAT-PMP Annoucements
91 mDNSexport const mDNSv6Addr AllHosts_v6 = { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x01 } };
92 mDNSexport const mDNSv6Addr NDP_prefix = { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x01, 0xFF,0x00,0x00,0xFB } }; // FF02:0:0:0:0:1:FF00::/104
93 mDNSexport const mDNSEthAddr AllHosts_v6_Eth = { { 0x33, 0x33, 0x00, 0x00, 0x00, 0x01 } };
94 mDNSexport const mDNSAddr AllDNSLinkGroup_v4 = { mDNSAddrType_IPv4, { { { 224, 0, 0, 251 } } } };
95 //mDNSexport const mDNSAddr AllDNSLinkGroup_v4 = { mDNSAddrType_IPv4, { { { 224, 0, 0, 252 } } } }; // LLMNR
96 mDNSexport const mDNSAddr AllDNSLinkGroup_v6 = { mDNSAddrType_IPv6, { { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0xFB } } } };
97 //mDNSexport const mDNSAddr AllDNSLinkGroup_v6 = { mDNSAddrType_IPv6, { { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x01,0x00,0x03 } } } }; // LLMNR
98
99 mDNSexport const mDNSOpaque16 zeroID = { { 0, 0 } };
100 mDNSexport const mDNSOpaque16 onesID = { { 255, 255 } };
101 mDNSexport const mDNSOpaque16 QueryFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery, 0 } };
102 mDNSexport const mDNSOpaque16 uQueryFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery | kDNSFlag0_RD, 0 } };
103 mDNSexport const mDNSOpaque16 ResponseFlags = { { kDNSFlag0_QR_Response | kDNSFlag0_OP_StdQuery | kDNSFlag0_AA, 0 } };
104 mDNSexport const mDNSOpaque16 UpdateReqFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_Update, 0 } };
105 mDNSexport const mDNSOpaque16 UpdateRespFlags = { { kDNSFlag0_QR_Response | kDNSFlag0_OP_Update, 0 } };
106
107 mDNSexport const mDNSOpaque64 zeroOpaque64 = { { 0 } };
108
109 // ***************************************************************************
110 #if COMPILER_LIKES_PRAGMA_MARK
111 #pragma mark -
112 #pragma mark - General Utility Functions
113 #endif
114
115 // return true for RFC1918 private addresses
116 mDNSexport mDNSBool mDNSv4AddrIsRFC1918(mDNSv4Addr *addr)
117 {
118 return ((addr->b[0] == 10) || // 10/8 prefix
119 (addr->b[0] == 172 && (addr->b[1] & 0xF0) == 16) || // 172.16/12
120 (addr->b[0] == 192 && addr->b[1] == 168)); // 192.168/16
121 }
122
123 mDNSexport NetworkInterfaceInfo *GetFirstActiveInterface(NetworkInterfaceInfo *intf)
124 {
125 while (intf && !intf->InterfaceActive) intf = intf->next;
126 return(intf);
127 }
128
129 mDNSexport mDNSInterfaceID GetNextActiveInterfaceID(const NetworkInterfaceInfo *intf)
130 {
131 const NetworkInterfaceInfo *next = GetFirstActiveInterface(intf->next);
132 if (next) return(next->InterfaceID); else return(mDNSNULL);
133 }
134
135 mDNSexport mDNSu32 NumCacheRecordsForInterfaceID(const mDNS *const m, mDNSInterfaceID id)
136 {
137 mDNSu32 slot, used = 0;
138 CacheGroup *cg;
139 const CacheRecord *rr;
140 FORALL_CACHERECORDS(slot, cg, rr)
141 if (rr->resrec.InterfaceID == id) used++;
142 return(used);
143 }
144
145 mDNSexport char *DNSTypeName(mDNSu16 rrtype)
146 {
147 switch (rrtype)
148 {
149 case kDNSType_A: return("Addr");
150 case kDNSType_NS: return("NS");
151 case kDNSType_CNAME:return("CNAME");
152 case kDNSType_SOA: return("SOA");
153 case kDNSType_NULL: return("NULL");
154 case kDNSType_PTR: return("PTR");
155 case kDNSType_HINFO:return("HINFO");
156 case kDNSType_TXT: return("TXT");
157 case kDNSType_AAAA: return("AAAA");
158 case kDNSType_SRV: return("SRV");
159 case kDNSType_OPT: return("OPT");
160 case kDNSType_NSEC: return("NSEC");
161 case kDNSType_TSIG: return("TSIG");
162 case kDNSQType_ANY: return("ANY");
163 default: {
164 static char buffer[16];
165 mDNS_snprintf(buffer, sizeof(buffer), "(%d)", rrtype);
166 return(buffer);
167 }
168 }
169 }
170
171 // Note slight bug: this code uses the rdlength from the ResourceRecord object, to display
172 // the rdata from the RDataBody object. Sometimes this could be the wrong length -- but as
173 // long as this routine is only used for debugging messages, it probably isn't a big problem.
174 mDNSexport char *GetRRDisplayString_rdb(const ResourceRecord *const rr, const RDataBody *const rd1, char *const buffer)
175 {
176 const RDataBody2 *const rd = (RDataBody2 *)rd1;
177 #define RemSpc (MaxMsg-1-length)
178 char *ptr = buffer;
179 mDNSu32 length = mDNS_snprintf(buffer, MaxMsg-1, "%4d %##s %s ", rr->rdlength, rr->name->c, DNSTypeName(rr->rrtype));
180 if (rr->RecordType == kDNSRecordTypePacketNegative) return(buffer);
181 if (!rr->rdlength) { mDNS_snprintf(buffer+length, RemSpc, "<< ZERO RDATA LENGTH >>"); return(buffer); }
182
183 switch (rr->rrtype)
184 {
185 case kDNSType_A: mDNS_snprintf(buffer+length, RemSpc, "%.4a", &rd->ipv4); break;
186
187 case kDNSType_NS: // Same as PTR
188 case kDNSType_CNAME:// Same as PTR
189 case kDNSType_PTR: mDNS_snprintf(buffer+length, RemSpc, "%##s", rd->name.c); break;
190
191 case kDNSType_SOA: mDNS_snprintf(buffer+length, RemSpc, "%##s %##s %d %d %d %d %d",
192 rd->soa.mname.c, rd->soa.rname.c,
193 rd->soa.serial, rd->soa.refresh, rd->soa.retry, rd->soa.expire, rd->soa.min);
194 break;
195
196 case kDNSType_HINFO:// Display this the same as TXT (show all constituent strings)
197 case kDNSType_TXT: {
198 const mDNSu8 *t = rd->txt.c;
199 while (t < rd->txt.c + rr->rdlength)
200 {
201 length += mDNS_snprintf(buffer+length, RemSpc, "%s%#s", t > rd->txt.c ? "¦" : "", t);
202 t += 1 + t[0];
203 }
204 } break;
205
206 case kDNSType_AAAA: mDNS_snprintf(buffer+length, RemSpc, "%.16a", &rd->ipv6); break;
207 case kDNSType_SRV: mDNS_snprintf(buffer+length, RemSpc, "%u %u %u %##s",
208 rd->srv.priority, rd->srv.weight, mDNSVal16(rd->srv.port), rd->srv.target.c); break;
209
210 case kDNSType_OPT: {
211 const rdataOPT *opt;
212 const rdataOPT *const end = (const rdataOPT *)&rd->data[rr->rdlength];
213 length += mDNS_snprintf(buffer+length, RemSpc, "Max %d", rr->rrclass);
214 for (opt = &rd->opt[0]; opt < end; opt++)
215 {
216 switch(opt->opt)
217 {
218 case kDNSOpt_LLQ:
219 length += mDNS_snprintf(buffer+length, RemSpc, " Vers %d", opt->u.llq.vers);
220 length += mDNS_snprintf(buffer+length, RemSpc, " Op %d", opt->u.llq.llqOp);
221 length += mDNS_snprintf(buffer+length, RemSpc, " Err/Port %d", opt->u.llq.err);
222 length += mDNS_snprintf(buffer+length, RemSpc, " ID %08X%08X", opt->u.llq.id.l[0], opt->u.llq.id.l[1]);
223 length += mDNS_snprintf(buffer+length, RemSpc, " Lease %d", opt->u.llq.llqlease);
224 break;
225 case kDNSOpt_Lease:
226 length += mDNS_snprintf(buffer+length, RemSpc, " Lease %d", opt->u.updatelease);
227 break;
228 case kDNSOpt_Owner:
229 length += mDNS_snprintf(buffer+length, RemSpc, " Vers %d", opt->u.owner.vers);
230 length += mDNS_snprintf(buffer+length, RemSpc, " Seq %3d", (mDNSu8)opt->u.owner.seq); // Display as unsigned
231 length += mDNS_snprintf(buffer+length, RemSpc, " MAC %.6a", opt->u.owner.HMAC.b);
232 if (opt->optlen >= DNSOpt_OwnerData_ID_Wake_Space-4)
233 {
234 length += mDNS_snprintf(buffer+length, RemSpc, " I-MAC %.6a", opt->u.owner.IMAC.b);
235 if (opt->optlen > DNSOpt_OwnerData_ID_Wake_Space-4)
236 length += mDNS_snprintf(buffer+length, RemSpc, " Password %.6a", opt->u.owner.password.b);
237 }
238 break;
239 default:
240 length += mDNS_snprintf(buffer+length, RemSpc, " Unknown %d", opt->opt);
241 break;
242 }
243 }
244 }
245 break;
246
247 case kDNSType_NSEC: {
248 mDNSu16 i;
249 for (i=0; i<255; i++)
250 if (rd->nsec.bitmap[i>>3] & (128 >> (i&7)))
251 length += mDNS_snprintf(buffer+length, RemSpc, "%s ", DNSTypeName(i));
252 }
253 break;
254
255 default: mDNS_snprintf(buffer+length, RemSpc, "RDLen %d: %s", rr->rdlength, rd->data);
256 // Really should scan buffer to check if text is valid UTF-8 and only replace with dots if not
257 for (ptr = buffer; *ptr; ptr++) if (*ptr < ' ') *ptr = '.';
258 break;
259 }
260 return(buffer);
261 }
262
263 // See comments in mDNSEmbeddedAPI.h
264 #if _PLATFORM_HAS_STRONG_PRNG_
265 #define mDNSRandomNumber mDNSPlatformRandomNumber
266 #else
267 mDNSlocal mDNSu32 mDNSRandomFromSeed(mDNSu32 seed)
268 {
269 return seed * 21 + 1;
270 }
271
272 mDNSlocal mDNSu32 mDNSMixRandomSeed(mDNSu32 seed, mDNSu8 iteration)
273 {
274 return iteration ? mDNSMixRandomSeed(mDNSRandomFromSeed(seed), --iteration) : seed;
275 }
276
277 mDNSlocal mDNSu32 mDNSRandomNumber()
278 {
279 static mDNSBool seeded = mDNSfalse;
280 static mDNSu32 seed = 0;
281 if (!seeded)
282 {
283 seed = mDNSMixRandomSeed(mDNSPlatformRandomSeed(), 100);
284 seeded = mDNStrue;
285 }
286 return (seed = mDNSRandomFromSeed(seed));
287 }
288 #endif // ! _PLATFORM_HAS_STRONG_PRNG_
289
290 mDNSexport mDNSu32 mDNSRandom(mDNSu32 max) // Returns pseudo-random result from zero to max inclusive
291 {
292 mDNSu32 ret = 0;
293 mDNSu32 mask = 1;
294
295 while (mask < max) mask = (mask << 1) | 1;
296
297 do ret = mDNSRandomNumber() & mask;
298 while (ret > max);
299
300 return ret;
301 }
302
303 mDNSexport mDNSBool mDNSSameAddress(const mDNSAddr *ip1, const mDNSAddr *ip2)
304 {
305 if (ip1->type == ip2->type)
306 {
307 switch (ip1->type)
308 {
309 case mDNSAddrType_None : return(mDNStrue); // Empty addresses have no data and are therefore always equal
310 case mDNSAddrType_IPv4 : return(mDNSBool)(mDNSSameIPv4Address(ip1->ip.v4, ip2->ip.v4));
311 case mDNSAddrType_IPv6 : return(mDNSBool)(mDNSSameIPv6Address(ip1->ip.v6, ip2->ip.v6));
312 }
313 }
314 return(mDNSfalse);
315 }
316
317 mDNSexport mDNSBool mDNSAddrIsDNSMulticast(const mDNSAddr *ip)
318 {
319 switch(ip->type)
320 {
321 case mDNSAddrType_IPv4: return(mDNSBool)(mDNSSameIPv4Address(ip->ip.v4, AllDNSLinkGroup_v4.ip.v4));
322 case mDNSAddrType_IPv6: return(mDNSBool)(mDNSSameIPv6Address(ip->ip.v6, AllDNSLinkGroup_v6.ip.v6));
323 default: return(mDNSfalse);
324 }
325 }
326
327 // ***************************************************************************
328 #if COMPILER_LIKES_PRAGMA_MARK
329 #pragma mark -
330 #pragma mark - Domain Name Utility Functions
331 #endif
332
333 mDNSexport mDNSBool SameDomainLabel(const mDNSu8 *a, const mDNSu8 *b)
334 {
335 int i;
336 const int len = *a++;
337
338 if (len > MAX_DOMAIN_LABEL)
339 { debugf("Malformed label (too long)"); return(mDNSfalse); }
340
341 if (len != *b++) return(mDNSfalse);
342 for (i=0; i<len; i++)
343 {
344 mDNSu8 ac = *a++;
345 mDNSu8 bc = *b++;
346 if (mDNSIsUpperCase(ac)) ac += 'a' - 'A';
347 if (mDNSIsUpperCase(bc)) bc += 'a' - 'A';
348 if (ac != bc) return(mDNSfalse);
349 }
350 return(mDNStrue);
351 }
352
353 mDNSexport mDNSBool SameDomainName(const domainname *const d1, const domainname *const d2)
354 {
355 const mDNSu8 * a = d1->c;
356 const mDNSu8 * b = d2->c;
357 const mDNSu8 *const max = d1->c + MAX_DOMAIN_NAME; // Maximum that's valid
358
359 while (*a || *b)
360 {
361 if (a + 1 + *a >= max)
362 { debugf("Malformed domain name (more than 256 characters)"); return(mDNSfalse); }
363 if (!SameDomainLabel(a, b)) return(mDNSfalse);
364 a += 1 + *a;
365 b += 1 + *b;
366 }
367
368 return(mDNStrue);
369 }
370
371 mDNSexport mDNSBool SameDomainNameCS(const domainname *const d1, const domainname *const d2)
372 {
373 mDNSu16 l1 = DomainNameLength(d1);
374 mDNSu16 l2 = DomainNameLength(d2);
375 return(l1 <= MAX_DOMAIN_NAME && l1 == l2 && mDNSPlatformMemSame(d1, d2, l1));
376 }
377
378 mDNSexport mDNSBool IsLocalDomain(const domainname *d)
379 {
380 // Domains that are defined to be resolved via link-local multicast are:
381 // local., 254.169.in-addr.arpa., and {8,9,A,B}.E.F.ip6.arpa.
382 static const domainname *nL = (const domainname*)"\x5" "local";
383 static const domainname *nR = (const domainname*)"\x3" "254" "\x3" "169" "\x7" "in-addr" "\x4" "arpa";
384 static const domainname *n8 = (const domainname*)"\x1" "8" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa";
385 static const domainname *n9 = (const domainname*)"\x1" "9" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa";
386 static const domainname *nA = (const domainname*)"\x1" "a" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa";
387 static const domainname *nB = (const domainname*)"\x1" "b" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa";
388
389 const domainname *d1, *d2, *d3, *d4, *d5; // Top-level domain, second-level domain, etc.
390 d1 = d2 = d3 = d4 = d5 = mDNSNULL;
391 while (d->c[0])
392 {
393 d5 = d4; d4 = d3; d3 = d2; d2 = d1; d1 = d;
394 d = (const domainname*)(d->c + 1 + d->c[0]);
395 }
396
397 if (d1 && SameDomainName(d1, nL)) return(mDNStrue);
398 if (d4 && SameDomainName(d4, nR)) return(mDNStrue);
399 if (d5 && SameDomainName(d5, n8)) return(mDNStrue);
400 if (d5 && SameDomainName(d5, n9)) return(mDNStrue);
401 if (d5 && SameDomainName(d5, nA)) return(mDNStrue);
402 if (d5 && SameDomainName(d5, nB)) return(mDNStrue);
403 return(mDNSfalse);
404 }
405
406 mDNSexport const mDNSu8 *LastLabel(const domainname *d)
407 {
408 const mDNSu8 *p = d->c;
409 while (d->c[0])
410 {
411 p = d->c;
412 d = (const domainname*)(d->c + 1 + d->c[0]);
413 }
414 return(p);
415 }
416
417 // Returns length of a domain name INCLUDING the byte for the final null label
418 // e.g. for the root label "." it returns one
419 // For the FQDN "com." it returns 5 (length byte, three data bytes, final zero)
420 // Legal results are 1 (just root label) to 256 (MAX_DOMAIN_NAME)
421 // If the given domainname is invalid, result is 257 (MAX_DOMAIN_NAME+1)
422 mDNSexport mDNSu16 DomainNameLengthLimit(const domainname *const name, const mDNSu8 *limit)
423 {
424 const mDNSu8 *src = name->c;
425 while (src < limit && *src <= MAX_DOMAIN_LABEL)
426 {
427 if (*src == 0) return((mDNSu16)(src - name->c + 1));
428 src += 1 + *src;
429 }
430 return(MAX_DOMAIN_NAME+1);
431 }
432
433 // CompressedDomainNameLength returns the length of a domain name INCLUDING the byte
434 // for the final null label, e.g. for the root label "." it returns one.
435 // E.g. for the FQDN "foo.com." it returns 9
436 // (length, three data bytes, length, three more data bytes, final zero).
437 // In the case where a parent domain name is provided, and the given name is a child
438 // of that parent, CompressedDomainNameLength returns the length of the prefix portion
439 // of the child name, plus TWO bytes for the compression pointer.
440 // E.g. for the name "foo.com." with parent "com.", it returns 6
441 // (length, three data bytes, two-byte compression pointer).
442 mDNSexport mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent)
443 {
444 const mDNSu8 *src = name->c;
445 if (parent && parent->c[0] == 0) parent = mDNSNULL;
446 while (*src)
447 {
448 if (*src > MAX_DOMAIN_LABEL) return(MAX_DOMAIN_NAME+1);
449 if (parent && SameDomainName((const domainname *)src, parent)) return((mDNSu16)(src - name->c + 2));
450 src += 1 + *src;
451 if (src - name->c >= MAX_DOMAIN_NAME) return(MAX_DOMAIN_NAME+1);
452 }
453 return((mDNSu16)(src - name->c + 1));
454 }
455
456 // CountLabels() returns number of labels in name, excluding final root label
457 // (e.g. for "apple.com." CountLabels returns 2.)
458 mDNSexport int CountLabels(const domainname *d)
459 {
460 int count = 0;
461 const mDNSu8 *ptr;
462 for (ptr = d->c; *ptr; ptr = ptr + ptr[0] + 1) count++;
463 return count;
464 }
465
466 // SkipLeadingLabels skips over the first 'skip' labels in the domainname,
467 // returning a pointer to the suffix with 'skip' labels removed.
468 mDNSexport const domainname *SkipLeadingLabels(const domainname *d, int skip)
469 {
470 while (skip > 0 && d->c[0]) { d = (const domainname *)(d->c + 1 + d->c[0]); skip--; }
471 return(d);
472 }
473
474 // AppendLiteralLabelString appends a single label to an existing (possibly empty) domainname.
475 // The C string contains the label as-is, with no escaping, etc.
476 // Any dots in the name are literal dots, not label separators
477 // If successful, AppendLiteralLabelString returns a pointer to the next unused byte
478 // in the domainname bufer (i.e. the next byte after the terminating zero).
479 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes)
480 // AppendLiteralLabelString returns mDNSNULL.
481 mDNSexport mDNSu8 *AppendLiteralLabelString(domainname *const name, const char *cstr)
482 {
483 mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name
484 const mDNSu8 *const lim1 = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero)
485 const mDNSu8 *const lim2 = ptr + 1 + MAX_DOMAIN_LABEL;
486 const mDNSu8 *const lim = (lim1 < lim2) ? lim1 : lim2;
487 mDNSu8 *lengthbyte = ptr++; // Record where the length is going to go
488
489 while (*cstr && ptr < lim) *ptr++ = (mDNSu8)*cstr++; // Copy the data
490 *lengthbyte = (mDNSu8)(ptr - lengthbyte - 1); // Fill in the length byte
491 *ptr++ = 0; // Put the null root label on the end
492 if (*cstr) return(mDNSNULL); // Failure: We didn't successfully consume all input
493 else return(ptr); // Success: return new value of ptr
494 }
495
496 // AppendDNSNameString appends zero or more labels to an existing (possibly empty) domainname.
497 // The C string is in conventional DNS syntax:
498 // Textual labels, escaped as necessary using the usual DNS '\' notation, separated by dots.
499 // If successful, AppendDNSNameString returns a pointer to the next unused byte
500 // in the domainname bufer (i.e. the next byte after the terminating zero).
501 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes)
502 // AppendDNSNameString returns mDNSNULL.
503 mDNSexport mDNSu8 *AppendDNSNameString(domainname *const name, const char *cstring)
504 {
505 const char *cstr = cstring;
506 mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name
507 const mDNSu8 *const lim = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero)
508 while (*cstr && ptr < lim) // While more characters, and space to put them...
509 {
510 mDNSu8 *lengthbyte = ptr++; // Record where the length is going to go
511 if (*cstr == '.') { LogMsg("AppendDNSNameString: Illegal empty label in name \"%s\"", cstring); return(mDNSNULL); }
512 while (*cstr && *cstr != '.' && ptr < lim) // While we have characters in the label...
513 {
514 mDNSu8 c = (mDNSu8)*cstr++; // Read the character
515 if (c == '\\') // If escape character, check next character
516 {
517 c = (mDNSu8)*cstr++; // Assume we'll just take the next character
518 if (mDNSIsDigit(cstr[-1]) && mDNSIsDigit(cstr[0]) && mDNSIsDigit(cstr[1]))
519 { // If three decimal digits,
520 int v0 = cstr[-1] - '0'; // then interpret as three-digit decimal
521 int v1 = cstr[ 0] - '0';
522 int v2 = cstr[ 1] - '0';
523 int val = v0 * 100 + v1 * 10 + v2;
524 if (val <= 255) { c = (mDNSu8)val; cstr += 2; } // If valid three-digit decimal value, use it
525 }
526 }
527 *ptr++ = c; // Write the character
528 }
529 if (*cstr) cstr++; // Skip over the trailing dot (if present)
530 if (ptr - lengthbyte - 1 > MAX_DOMAIN_LABEL) // If illegal label, abort
531 return(mDNSNULL);
532 *lengthbyte = (mDNSu8)(ptr - lengthbyte - 1); // Fill in the length byte
533 }
534
535 *ptr++ = 0; // Put the null root label on the end
536 if (*cstr) return(mDNSNULL); // Failure: We didn't successfully consume all input
537 else return(ptr); // Success: return new value of ptr
538 }
539
540 // AppendDomainLabel appends a single label to a name.
541 // If successful, AppendDomainLabel returns a pointer to the next unused byte
542 // in the domainname bufer (i.e. the next byte after the terminating zero).
543 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes)
544 // AppendDomainLabel returns mDNSNULL.
545 mDNSexport mDNSu8 *AppendDomainLabel(domainname *const name, const domainlabel *const label)
546 {
547 int i;
548 mDNSu8 *ptr = name->c + DomainNameLength(name) - 1;
549
550 // Check label is legal
551 if (label->c[0] > MAX_DOMAIN_LABEL) return(mDNSNULL);
552
553 // Check that ptr + length byte + data bytes + final zero does not exceed our limit
554 if (ptr + 1 + label->c[0] + 1 > name->c + MAX_DOMAIN_NAME) return(mDNSNULL);
555
556 for (i=0; i<=label->c[0]; i++) *ptr++ = label->c[i]; // Copy the label data
557 *ptr++ = 0; // Put the null root label on the end
558 return(ptr);
559 }
560
561 mDNSexport mDNSu8 *AppendDomainName(domainname *const name, const domainname *const append)
562 {
563 mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name
564 const mDNSu8 *const lim = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero)
565 const mDNSu8 * src = append->c;
566 while (src[0])
567 {
568 int i;
569 if (ptr + 1 + src[0] > lim) return(mDNSNULL);
570 for (i=0; i<=src[0]; i++) *ptr++ = src[i];
571 *ptr = 0; // Put the null root label on the end
572 src += i;
573 }
574 return(ptr);
575 }
576
577 // MakeDomainLabelFromLiteralString makes a single domain label from a single literal C string (with no escaping).
578 // If successful, MakeDomainLabelFromLiteralString returns mDNStrue.
579 // If unable to convert the whole string to a legal domain label (i.e. because length is more than 63 bytes) then
580 // MakeDomainLabelFromLiteralString makes a legal domain label from the first 63 bytes of the string and returns mDNSfalse.
581 // In some cases silently truncated oversized names to 63 bytes is acceptable, so the return result may be ignored.
582 // In other cases silent truncation may not be acceptable, so in those cases the calling function needs to check the return result.
583 mDNSexport mDNSBool MakeDomainLabelFromLiteralString(domainlabel *const label, const char *cstr)
584 {
585 mDNSu8 * ptr = label->c + 1; // Where we're putting it
586 const mDNSu8 *const limit = label->c + 1 + MAX_DOMAIN_LABEL; // The maximum we can put
587 while (*cstr && ptr < limit) *ptr++ = (mDNSu8)*cstr++; // Copy the label
588 label->c[0] = (mDNSu8)(ptr - label->c - 1); // Set the length byte
589 return(*cstr == 0); // Return mDNStrue if we successfully consumed all input
590 }
591
592 // MakeDomainNameFromDNSNameString makes a native DNS-format domainname from a C string.
593 // The C string is in conventional DNS syntax:
594 // Textual labels, escaped as necessary using the usual DNS '\' notation, separated by dots.
595 // If successful, MakeDomainNameFromDNSNameString returns a pointer to the next unused byte
596 // in the domainname bufer (i.e. the next byte after the terminating zero).
597 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes)
598 // MakeDomainNameFromDNSNameString returns mDNSNULL.
599 mDNSexport mDNSu8 *MakeDomainNameFromDNSNameString(domainname *const name, const char *cstr)
600 {
601 name->c[0] = 0; // Make an empty domain name
602 return(AppendDNSNameString(name, cstr)); // And then add this string to it
603 }
604
605 mDNSexport char *ConvertDomainLabelToCString_withescape(const domainlabel *const label, char *ptr, char esc)
606 {
607 const mDNSu8 * src = label->c; // Domain label we're reading
608 const mDNSu8 len = *src++; // Read length of this (non-null) label
609 const mDNSu8 *const end = src + len; // Work out where the label ends
610 if (len > MAX_DOMAIN_LABEL) return(mDNSNULL); // If illegal label, abort
611 while (src < end) // While we have characters in the label
612 {
613 mDNSu8 c = *src++;
614 if (esc)
615 {
616 if (c == '.' || c == esc) // If character is a dot or the escape character
617 *ptr++ = esc; // Output escape character
618 else if (c <= ' ') // If non-printing ascii,
619 { // Output decimal escape sequence
620 *ptr++ = esc;
621 *ptr++ = (char) ('0' + (c / 100) );
622 *ptr++ = (char) ('0' + (c / 10) % 10);
623 c = (mDNSu8)('0' + (c ) % 10);
624 }
625 }
626 *ptr++ = (char)c; // Copy the character
627 }
628 *ptr = 0; // Null-terminate the string
629 return(ptr); // and return
630 }
631
632 // Note: To guarantee that there will be no possible overrun, cstr must be at least MAX_ESCAPED_DOMAIN_NAME (1009 bytes)
633 mDNSexport char *ConvertDomainNameToCString_withescape(const domainname *const name, char *ptr, char esc)
634 {
635 const mDNSu8 *src = name->c; // Domain name we're reading
636 const mDNSu8 *const max = name->c + MAX_DOMAIN_NAME; // Maximum that's valid
637
638 if (*src == 0) *ptr++ = '.'; // Special case: For root, just write a dot
639
640 while (*src) // While more characters in the domain name
641 {
642 if (src + 1 + *src >= max) return(mDNSNULL);
643 ptr = ConvertDomainLabelToCString_withescape((const domainlabel *)src, ptr, esc);
644 if (!ptr) return(mDNSNULL);
645 src += 1 + *src;
646 *ptr++ = '.'; // Write the dot after the label
647 }
648
649 *ptr++ = 0; // Null-terminate the string
650 return(ptr); // and return
651 }
652
653 // RFC 1034 rules:
654 // Host names must start with a letter, end with a letter or digit,
655 // and have as interior characters only letters, digits, and hyphen.
656 // This was subsequently modified in RFC 1123 to allow the first character to be either a letter or a digit
657
658 mDNSexport void ConvertUTF8PstringToRFC1034HostLabel(const mDNSu8 UTF8Name[], domainlabel *const hostlabel)
659 {
660 const mDNSu8 * src = &UTF8Name[1];
661 const mDNSu8 *const end = &UTF8Name[1] + UTF8Name[0];
662 mDNSu8 * ptr = &hostlabel->c[1];
663 const mDNSu8 *const lim = &hostlabel->c[1] + MAX_DOMAIN_LABEL;
664 while (src < end)
665 {
666 // Delete apostrophes from source name
667 if (src[0] == '\'') { src++; continue; } // Standard straight single quote
668 if (src + 2 < end && src[0] == 0xE2 && src[1] == 0x80 && src[2] == 0x99)
669 { src += 3; continue; } // Unicode curly apostrophe
670 if (ptr < lim)
671 {
672 if (mDNSValidHostChar(*src, (ptr > &hostlabel->c[1]), (src < end-1))) *ptr++ = *src;
673 else if (ptr > &hostlabel->c[1] && ptr[-1] != '-') *ptr++ = '-';
674 }
675 src++;
676 }
677 while (ptr > &hostlabel->c[1] && ptr[-1] == '-') ptr--; // Truncate trailing '-' marks
678 hostlabel->c[0] = (mDNSu8)(ptr - &hostlabel->c[1]);
679 }
680
681 #define ValidTransportProtocol(X) ( (X)[0] == 4 && (X)[1] == '_' && \
682 ((((X)[2] | 0x20) == 'u' && ((X)[3] | 0x20) == 'd') || (((X)[2] | 0x20) == 't' && ((X)[3] | 0x20) == 'c')) && \
683 ((X)[4] | 0x20) == 'p')
684
685 mDNSexport mDNSu8 *ConstructServiceName(domainname *const fqdn,
686 const domainlabel *name, const domainname *type, const domainname *const domain)
687 {
688 int i, len;
689 mDNSu8 *dst = fqdn->c;
690 const mDNSu8 *src;
691 const char *errormsg;
692 #if APPLE_OSX_mDNSResponder
693 mDNSBool loggedUnderscore = mDNSfalse;
694 static char typeBuf[MAX_ESCAPED_DOMAIN_NAME];
695 #endif
696
697 // In the case where there is no name (and ONLY in that case),
698 // a single-label subtype is allowed as the first label of a three-part "type"
699 if (!name && type)
700 {
701 const mDNSu8 *s0 = type->c;
702 if (s0[0] && s0[0] < 0x40) // If legal first label (at least one character, and no more than 63)
703 {
704 const mDNSu8 * s1 = s0 + 1 + s0[0];
705 if (s1[0] && s1[0] < 0x40) // and legal second label (at least one character, and no more than 63)
706 {
707 const mDNSu8 *s2 = s1 + 1 + s1[0];
708 if (s2[0] && s2[0] < 0x40 && s2[1+s2[0]] == 0) // and we have three and only three labels
709 {
710 static const mDNSu8 SubTypeLabel[5] = "\x04_sub";
711 src = s0; // Copy the first label
712 len = *src;
713 for (i=0; i <= len; i++) *dst++ = *src++;
714 for (i=0; i < (int)sizeof(SubTypeLabel); i++) *dst++ = SubTypeLabel[i];
715 type = (const domainname *)s1;
716
717 // Special support to enable the DNSServiceBrowse call made by Bonjour Browser
718 // For these queries, we retract the "._sub" we just added between the subtype and the main type
719 // Remove after Bonjour Browser is updated to use DNSServiceQueryRecord instead of DNSServiceBrowse
720 if (SameDomainName((domainname*)s0, (const domainname*)"\x09_services\x07_dns-sd\x04_udp"))
721 dst -= sizeof(SubTypeLabel);
722 }
723 }
724 }
725 }
726
727 if (name && name->c[0])
728 {
729 src = name->c; // Put the service name into the domain name
730 len = *src;
731 if (len >= 0x40) { errormsg = "Service instance name too long"; goto fail; }
732 for (i=0; i<=len; i++) *dst++ = *src++;
733 }
734 else
735 name = (domainlabel*)""; // Set this up to be non-null, to avoid errors if we have to call LogMsg() below
736
737 src = type->c; // Put the service type into the domain name
738 len = *src;
739 if (len < 2 || len > 16)
740 {
741 LogMsg("Bad service type in %#s.%##s%##s Application protocol name must be underscore plus 1-15 characters. "
742 "See <http://www.dns-sd.org/ServiceTypes.html>", name->c, type->c, domain->c);
743 #if APPLE_OSX_mDNSResponder
744 ConvertDomainNameToCString(type, typeBuf);
745 mDNSASLLog(mDNSNULL, "serviceType.nameTooLong", "noop", typeBuf, "");
746 #endif
747 }
748 if (len < 2 || len >= 0x40 || (len > 16 && !SameDomainName(domain, &localdomain))) return(mDNSNULL);
749 if (src[1] != '_') { errormsg = "Application protocol name must begin with underscore"; goto fail; }
750 for (i=2; i<=len; i++)
751 {
752 // Letters and digits are allowed anywhere
753 if (mDNSIsLetter(src[i]) || mDNSIsDigit(src[i])) continue;
754 // Hyphens are only allowed as interior characters
755 // Underscores are not supposed to be allowed at all, but for backwards compatibility with some old products we do allow them,
756 // with the same rule as hyphens
757 if ((src[i] == '-' || src[i] == '_') && i > 2 && i < len)
758 {
759 #if APPLE_OSX_mDNSResponder
760 if (src[i] == '_' && loggedUnderscore == mDNSfalse)
761 {
762 ConvertDomainNameToCString(type, typeBuf);
763 mDNSASLLog(mDNSNULL, "serviceType.nameWithUnderscore", "noop", typeBuf, "");
764 loggedUnderscore = mDNStrue;
765 }
766 #endif
767 continue;
768 }
769 errormsg = "Application protocol name must contain only letters, digits, and hyphens";
770 #if APPLE_OSX_mDNSResponder
771 {
772 ConvertDomainNameToCString(type, typeBuf);
773 mDNSASLLog(mDNSNULL, "serviceType.nameWithIllegalCharacters", "noop", typeBuf, "");
774 }
775 #endif
776 goto fail;
777 }
778 for (i=0; i<=len; i++) *dst++ = *src++;
779
780 len = *src;
781 if (!ValidTransportProtocol(src)) { errormsg = "Transport protocol name must be _udp or _tcp"; goto fail; }
782 for (i=0; i<=len; i++) *dst++ = *src++;
783
784 if (*src) { errormsg = "Service type must have only two labels"; goto fail; }
785
786 *dst = 0;
787 if (!domain->c[0]) { errormsg = "Service domain must be non-empty"; goto fail; }
788 if (SameDomainName(domain, (const domainname*)"\x05" "local" "\x04" "arpa"))
789 { errormsg = "Illegal domain \"local.arpa.\" Use \"local.\" (or empty string)"; goto fail; }
790 dst = AppendDomainName(fqdn, domain);
791 if (!dst) { errormsg = "Service domain too long"; goto fail; }
792 return(dst);
793
794 fail:
795 LogMsg("ConstructServiceName: %s: %#s.%##s%##s", errormsg, name->c, type->c, domain->c);
796 return(mDNSNULL);
797 }
798
799 // A service name has the form: instance.application-protocol.transport-protocol.domain
800 // DeconstructServiceName is currently fairly forgiving: It doesn't try to enforce character
801 // set or length limits for the protocol names, and the final domain is allowed to be empty.
802 // However, if the given FQDN doesn't contain at least three labels,
803 // DeconstructServiceName will reject it and return mDNSfalse.
804 mDNSexport mDNSBool DeconstructServiceName(const domainname *const fqdn,
805 domainlabel *const name, domainname *const type, domainname *const domain)
806 {
807 int i, len;
808 const mDNSu8 *src = fqdn->c;
809 const mDNSu8 *max = fqdn->c + MAX_DOMAIN_NAME;
810 mDNSu8 *dst;
811
812 dst = name->c; // Extract the service name
813 len = *src;
814 if (!len) { debugf("DeconstructServiceName: FQDN empty!"); return(mDNSfalse); }
815 if (len >= 0x40) { debugf("DeconstructServiceName: Instance name too long"); return(mDNSfalse); }
816 for (i=0; i<=len; i++) *dst++ = *src++;
817
818 dst = type->c; // Extract the service type
819 len = *src;
820 if (!len) { debugf("DeconstructServiceName: FQDN contains only one label!"); return(mDNSfalse); }
821 if (len >= 0x40) { debugf("DeconstructServiceName: Application protocol name too long"); return(mDNSfalse); }
822 if (src[1] != '_'){ debugf("DeconstructServiceName: No _ at start of application protocol"); return(mDNSfalse); }
823 for (i=0; i<=len; i++) *dst++ = *src++;
824
825 len = *src;
826 if (!len) { debugf("DeconstructServiceName: FQDN contains only two labels!"); return(mDNSfalse); }
827 if (!ValidTransportProtocol(src))
828 { debugf("DeconstructServiceName: Transport protocol must be _udp or _tcp"); return(mDNSfalse); }
829 for (i=0; i<=len; i++) *dst++ = *src++;
830 *dst++ = 0; // Put terminator on the end of service type
831
832 dst = domain->c; // Extract the service domain
833 while (*src)
834 {
835 len = *src;
836 if (len >= 0x40)
837 { debugf("DeconstructServiceName: Label in service domain too long"); return(mDNSfalse); }
838 if (src + 1 + len + 1 >= max)
839 { debugf("DeconstructServiceName: Total service domain too long"); return(mDNSfalse); }
840 for (i=0; i<=len; i++) *dst++ = *src++;
841 }
842 *dst++ = 0; // Put the null root label on the end
843
844 return(mDNStrue);
845 }
846
847 // Notes on UTF-8:
848 // 0xxxxxxx represents a 7-bit ASCII value from 0x00 to 0x7F
849 // 10xxxxxx is a continuation byte of a multi-byte character
850 // 110xxxxx is the first byte of a 2-byte character (11 effective bits; values 0x 80 - 0x 800-1)
851 // 1110xxxx is the first byte of a 3-byte character (16 effective bits; values 0x 800 - 0x 10000-1)
852 // 11110xxx is the first byte of a 4-byte character (21 effective bits; values 0x 10000 - 0x 200000-1)
853 // 111110xx is the first byte of a 5-byte character (26 effective bits; values 0x 200000 - 0x 4000000-1)
854 // 1111110x is the first byte of a 6-byte character (31 effective bits; values 0x4000000 - 0x80000000-1)
855 //
856 // UTF-16 surrogate pairs are used in UTF-16 to encode values larger than 0xFFFF.
857 // Although UTF-16 surrogate pairs are not supposed to appear in legal UTF-8, we want to be defensive
858 // about that too. (See <http://www.unicode.org/faq/utf_bom.html#34>, "What are surrogates?")
859 // The first of pair is a UTF-16 value in the range 0xD800-0xDBFF (11101101 1010xxxx 10xxxxxx in UTF-8),
860 // and the second is a UTF-16 value in the range 0xDC00-0xDFFF (11101101 1011xxxx 10xxxxxx in UTF-8).
861
862 mDNSexport mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max)
863 {
864 if (length > max)
865 {
866 mDNSu8 c1 = string[max]; // First byte after cut point
867 mDNSu8 c2 = (max+1 < length) ? string[max+1] : (mDNSu8)0xB0; // Second byte after cut point
868 length = max; // Trim length down
869 while (length > 0)
870 {
871 // Check if the byte right after the chop point is a UTF-8 continuation byte,
872 // or if the character right after the chop point is the second of a UTF-16 surrogate pair.
873 // If so, then we continue to chop more bytes until we get to a legal chop point.
874 mDNSBool continuation = ((c1 & 0xC0) == 0x80);
875 mDNSBool secondsurrogate = (c1 == 0xED && (c2 & 0xF0) == 0xB0);
876 if (!continuation && !secondsurrogate) break;
877 c2 = c1;
878 c1 = string[--length];
879 }
880 // Having truncated characters off the end of our string, also cut off any residual white space
881 while (length > 0 && string[length-1] <= ' ') length--;
882 }
883 return(length);
884 }
885
886 // Returns true if a rich text label ends in " (nnn)", or if an RFC 1034
887 // name ends in "-nnn", where n is some decimal number.
888 mDNSexport mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText)
889 {
890 mDNSu16 l = name->c[0];
891
892 if (RichText)
893 {
894 if (l < 4) return mDNSfalse; // Need at least " (2)"
895 if (name->c[l--] != ')') return mDNSfalse; // Last char must be ')'
896 if (!mDNSIsDigit(name->c[l])) return mDNSfalse; // Preceeded by a digit
897 l--;
898 while (l > 2 && mDNSIsDigit(name->c[l])) l--; // Strip off digits
899 return (name->c[l] == '(' && name->c[l - 1] == ' ');
900 }
901 else
902 {
903 if (l < 2) return mDNSfalse; // Need at least "-2"
904 if (!mDNSIsDigit(name->c[l])) return mDNSfalse; // Last char must be a digit
905 l--;
906 while (l > 2 && mDNSIsDigit(name->c[l])) l--; // Strip off digits
907 return (name->c[l] == '-');
908 }
909 }
910
911 // removes an auto-generated suffix (appended on a name collision) from a label. caller is
912 // responsible for ensuring that the label does indeed contain a suffix. returns the number
913 // from the suffix that was removed.
914 mDNSexport mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText)
915 {
916 mDNSu32 val = 0, multiplier = 1;
917
918 // Chop closing parentheses from RichText suffix
919 if (RichText && name->c[0] >= 1 && name->c[name->c[0]] == ')') name->c[0]--;
920
921 // Get any existing numerical suffix off the name
922 while (mDNSIsDigit(name->c[name->c[0]]))
923 { val += (name->c[name->c[0]] - '0') * multiplier; multiplier *= 10; name->c[0]--; }
924
925 // Chop opening parentheses or dash from suffix
926 if (RichText)
927 {
928 if (name->c[0] >= 2 && name->c[name->c[0]] == '(' && name->c[name->c[0]-1] == ' ') name->c[0] -= 2;
929 }
930 else
931 {
932 if (name->c[0] >= 1 && name->c[name->c[0]] == '-') name->c[0] -= 1;
933 }
934
935 return(val);
936 }
937
938 // appends a numerical suffix to a label, with the number following a whitespace and enclosed
939 // in parentheses (rich text) or following two consecutive hyphens (RFC 1034 domain label).
940 mDNSexport void AppendLabelSuffix(domainlabel *const name, mDNSu32 val, const mDNSBool RichText)
941 {
942 mDNSu32 divisor = 1, chars = 2; // Shortest possible RFC1034 name suffix is 2 characters ("-2")
943 if (RichText) chars = 4; // Shortest possible RichText suffix is 4 characters (" (2)")
944
945 // Truncate trailing spaces from RichText names
946 if (RichText) while (name->c[name->c[0]] == ' ') name->c[0]--;
947
948 while (divisor < 0xFFFFFFFFUL/10 && val >= divisor * 10) { divisor *= 10; chars++; }
949
950 name->c[0] = (mDNSu8) TruncateUTF8ToLength(name->c+1, name->c[0], MAX_DOMAIN_LABEL - chars);
951
952 if (RichText) { name->c[++name->c[0]] = ' '; name->c[++name->c[0]] = '('; }
953 else { name->c[++name->c[0]] = '-'; }
954
955 while (divisor)
956 {
957 name->c[++name->c[0]] = (mDNSu8)('0' + val / divisor);
958 val %= divisor;
959 divisor /= 10;
960 }
961
962 if (RichText) name->c[++name->c[0]] = ')';
963 }
964
965 mDNSexport void IncrementLabelSuffix(domainlabel *name, mDNSBool RichText)
966 {
967 mDNSu32 val = 0;
968
969 if (LabelContainsSuffix(name, RichText))
970 val = RemoveLabelSuffix(name, RichText);
971
972 // If no existing suffix, start by renaming "Foo" as "Foo (2)" or "Foo-2" as appropriate.
973 // If existing suffix in the range 2-9, increment it.
974 // If we've had ten conflicts already, there are probably too many hosts trying to use the same name,
975 // so add a random increment to improve the chances of finding an available name next time.
976 if (val == 0) val = 2;
977 else if (val < 10) val++;
978 else val += 1 + mDNSRandom(99);
979
980 AppendLabelSuffix(name, val, RichText);
981 }
982
983 // ***************************************************************************
984 #if COMPILER_LIKES_PRAGMA_MARK
985 #pragma mark -
986 #pragma mark - Resource Record Utility Functions
987 #endif
988
989 // Set up a AuthRecord with sensible default values.
990 // These defaults may be overwritten with new values before mDNS_Register is called
991 mDNSexport void mDNS_SetupResourceRecord(AuthRecord *rr, RData *RDataStorage, mDNSInterfaceID InterfaceID,
992 mDNSu16 rrtype, mDNSu32 ttl, mDNSu8 RecordType, mDNSRecordCallback Callback, void *Context)
993 {
994 // Don't try to store a TTL bigger than we can represent in platform time units
995 if (ttl > 0x7FFFFFFFUL / mDNSPlatformOneSecond)
996 ttl = 0x7FFFFFFFUL / mDNSPlatformOneSecond;
997 else if (ttl == 0) // And Zero TTL is illegal
998 ttl = DefaultTTLforRRType(rrtype);
999
1000 // Field Group 1: The actual information pertaining to this resource record
1001 rr->resrec.RecordType = RecordType;
1002 rr->resrec.InterfaceID = InterfaceID;
1003 rr->resrec.name = &rr->namestorage;
1004 rr->resrec.rrtype = rrtype;
1005 rr->resrec.rrclass = kDNSClass_IN;
1006 rr->resrec.rroriginalttl = ttl;
1007 rr->resrec.rDNSServer = mDNSNULL;
1008 // rr->resrec.rdlength = MUST set by client and/or in mDNS_Register_internal
1009 // rr->resrec.rdestimate = set in mDNS_Register_internal
1010 // rr->resrec.rdata = MUST be set by client
1011
1012 if (RDataStorage)
1013 rr->resrec.rdata = RDataStorage;
1014 else
1015 {
1016 rr->resrec.rdata = &rr->rdatastorage;
1017 rr->resrec.rdata->MaxRDLength = sizeof(RDataBody);
1018 }
1019
1020 // Field Group 2: Persistent metadata for Authoritative Records
1021 rr->Additional1 = mDNSNULL;
1022 rr->Additional2 = mDNSNULL;
1023 rr->DependentOn = mDNSNULL;
1024 rr->RRSet = mDNSNULL;
1025 rr->RecordCallback = Callback;
1026 rr->RecordContext = Context;
1027
1028 rr->AutoTarget = Target_Manual;
1029 rr->AllowRemoteQuery = mDNSfalse;
1030 rr->ForceMCast = mDNSfalse;
1031
1032 rr->WakeUp = zeroOwner;
1033 rr->AddressProxy = zeroAddr;
1034 rr->TimeRcvd = 0;
1035 rr->TimeExpire = 0;
1036
1037 // Field Group 3: Transient state for Authoritative Records (set in mDNS_Register_internal)
1038 // Field Group 4: Transient uDNS state for Authoritative Records (set in mDNS_Register_internal)
1039
1040 // For now, until the uDNS code is fully integrated, it's helpful to zero the uDNS state fields here too, just in case
1041 // (e.g. uDNS_RegisterService short-circuits the usual mDNS_Register_internal record registration calls, so a bunch
1042 // of fields don't get set up properly. In particular, if we don't zero rr->QueuedRData then the uDNS code crashes.)
1043 rr->state = regState_Zero;
1044 rr->uselease = 0;
1045 rr->expire = 0;
1046 rr->Private = 0;
1047 rr->updateid = zeroID;
1048 rr->zone = rr->resrec.name;
1049 rr->nta = mDNSNULL;
1050 rr->tcp = mDNSNULL;
1051 rr->OrigRData = 0;
1052 rr->OrigRDLen = 0;
1053 rr->InFlightRData = 0;
1054 rr->InFlightRDLen = 0;
1055 rr->QueuedRData = 0;
1056 rr->QueuedRDLen = 0;
1057 mDNSPlatformMemZero(&rr->NATinfo, sizeof(rr->NATinfo));
1058 rr->SRVChanged = mDNSfalse;
1059 rr->mState = mergeState_Zero;
1060
1061 rr->namestorage.c[0] = 0; // MUST be set by client before calling mDNS_Register()
1062 }
1063
1064 mDNSexport void mDNS_SetupQuestion(DNSQuestion *const q, const mDNSInterfaceID InterfaceID, const domainname *const name,
1065 const mDNSu16 qtype, mDNSQuestionCallback *const callback, void *const context)
1066 {
1067 q->InterfaceID = InterfaceID;
1068 q->Target = zeroAddr;
1069 AssignDomainName(&q->qname, name);
1070 q->qtype = qtype;
1071 q->qclass = kDNSClass_IN;
1072 q->LongLived = (qtype == kDNSType_PTR);
1073 q->ExpectUnique = (qtype != kDNSType_PTR);
1074 q->ForceMCast = mDNSfalse;
1075 q->ReturnIntermed = mDNSfalse;
1076 q->SuppressUnusable = mDNSfalse;
1077 q->QuestionCallback = callback;
1078 q->QuestionContext = context;
1079 }
1080
1081 mDNSexport mDNSu32 RDataHashValue(const ResourceRecord *const rr)
1082 {
1083 int len = rr->rdlength;
1084 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data;
1085 switch(rr->rrtype)
1086 {
1087 case kDNSType_NS:
1088 case kDNSType_CNAME:
1089 case kDNSType_PTR:
1090 case kDNSType_DNAME: return DomainNameHashValue(&rdb->name);
1091
1092 case kDNSType_SOA: return rdb->soa.serial +
1093 rdb->soa.refresh +
1094 rdb->soa.retry +
1095 rdb->soa.expire +
1096 rdb->soa.min +
1097 DomainNameHashValue(&rdb->soa.mname) +
1098 DomainNameHashValue(&rdb->soa.rname);
1099
1100 case kDNSType_MX:
1101 case kDNSType_AFSDB:
1102 case kDNSType_RT:
1103 case kDNSType_KX: return DomainNameHashValue(&rdb->mx.exchange);
1104
1105 case kDNSType_RP: return DomainNameHashValue(&rdb->rp.mbox) + DomainNameHashValue(&rdb->rp.txt);
1106
1107 case kDNSType_PX: return DomainNameHashValue(&rdb->px.map822) + DomainNameHashValue(&rdb->px.mapx400);
1108
1109 case kDNSType_SRV: return DomainNameHashValue(&rdb->srv.target);
1110
1111 case kDNSType_OPT: return 0; // OPT is a pseudo-RR container structure; makes no sense to compare
1112
1113 case kDNSType_NSEC: len = sizeof(rdataNSEC); // Use in-memory length of 32, and fall through default checksum computation below
1114
1115 default:
1116 {
1117 mDNSu32 sum = 0;
1118 int i;
1119 for (i=0; i+1 < len; i+=2)
1120 {
1121 sum += (((mDNSu32)(rdb->data[i])) << 8) | rdb->data[i+1];
1122 sum = (sum<<3) | (sum>>29);
1123 }
1124 if (i < len)
1125 {
1126 sum += ((mDNSu32)(rdb->data[i])) << 8;
1127 }
1128 return(sum);
1129 }
1130 }
1131 }
1132
1133 // r1 has to be a full ResourceRecord including rrtype and rdlength
1134 // r2 is just a bare RDataBody, which MUST be the same rrtype and rdlength as r1
1135 mDNSexport mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2, DomainNameComparisonFn *samename)
1136 {
1137 const RDataBody2 *const b1 = (RDataBody2 *)r1->rdata->u.data;
1138 const RDataBody2 *const b2 = (RDataBody2 *)r2;
1139 switch(r1->rrtype)
1140 {
1141 case kDNSType_NS:
1142 case kDNSType_CNAME:
1143 case kDNSType_PTR:
1144 case kDNSType_DNAME:return(SameDomainName(&b1->name, &b2->name));
1145
1146 case kDNSType_SOA: return(mDNSBool)( b1->soa.serial == b2->soa.serial &&
1147 b1->soa.refresh == b2->soa.refresh &&
1148 b1->soa.retry == b2->soa.retry &&
1149 b1->soa.expire == b2->soa.expire &&
1150 b1->soa.min == b2->soa.min &&
1151 samename(&b1->soa.mname, &b2->soa.mname) &&
1152 samename(&b1->soa.rname, &b2->soa.rname));
1153
1154 case kDNSType_MX:
1155 case kDNSType_AFSDB:
1156 case kDNSType_RT:
1157 case kDNSType_KX: return(mDNSBool)( b1->mx.preference == b2->mx.preference &&
1158 samename(&b1->mx.exchange, &b2->mx.exchange));
1159
1160 case kDNSType_RP: return(mDNSBool)( samename(&b1->rp.mbox, &b2->rp.mbox) &&
1161 samename(&b1->rp.txt, &b2->rp.txt));
1162
1163 case kDNSType_PX: return(mDNSBool)( b1->px.preference == b2->px.preference &&
1164 samename(&b1->px.map822, &b2->px.map822) &&
1165 samename(&b1->px.mapx400, &b2->px.mapx400));
1166
1167 case kDNSType_SRV: return(mDNSBool)( b1->srv.priority == b2->srv.priority &&
1168 b1->srv.weight == b2->srv.weight &&
1169 mDNSSameIPPort(b1->srv.port, b2->srv.port) &&
1170 samename(&b1->srv.target, &b2->srv.target));
1171
1172 case kDNSType_OPT: return mDNSfalse; // OPT is a pseudo-RR container structure; makes no sense to compare
1173
1174 case kDNSType_NSEC: return(mDNSPlatformMemSame(b1->data, b2->data, sizeof(rdataNSEC)));
1175
1176 default: return(mDNSPlatformMemSame(b1->data, b2->data, r1->rdlength));
1177 }
1178 }
1179
1180 // ResourceRecordAnswersQuestion returns mDNStrue if the given resource record is a valid answer to the given question.
1181 // SameNameRecordAnswersQuestion is the same, except it skips the expensive SameDomainName() call.
1182 // SameDomainName() is generally cheap when the names don't match, but expensive when they do match,
1183 // because it has to check all the way to the end of the names to be sure.
1184 // In cases where we know in advance that the names match it's especially advantageous to skip the
1185 // SameDomainName() call because that's precisely the time when it's most expensive and least useful.
1186
1187 mDNSexport mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q)
1188 {
1189 if (rr->InterfaceID &&
1190 q ->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly &&
1191 rr->InterfaceID != q->InterfaceID) return(mDNSfalse);
1192
1193 // Resource record received via unicast, the DNSServer entries should match ?
1194 if (!rr->InterfaceID && rr->rDNSServer != q->qDNSServer) return(mDNSfalse);
1195
1196 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question
1197 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse);
1198
1199 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class.
1200 if (!RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse);
1201 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse);
1202
1203 return(mDNStrue);
1204 }
1205
1206 mDNSexport mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q)
1207 {
1208 if (rr->InterfaceID &&
1209 q ->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly &&
1210 rr->InterfaceID != q->InterfaceID) return(mDNSfalse);
1211
1212 // Resource record received via unicast, the DNSServer entries should match ?
1213 if (!rr->InterfaceID && rr->rDNSServer != q->qDNSServer) return(mDNSfalse);
1214
1215 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question.
1216 // This also covers the case where the ResourceRecord is mDNSInterface_LocalOnly and the question is expecting a unicast
1217 // DNS response. We don't want a local process to be able to create a fake LocalOnly address record for "www.bigbank.com"
1218 // which would then cause other applications (e.g. Safari) to connect to the wrong address. If we decide to support this later,
1219 // the restrictions need to be at least as strict as the restrictions on who can edit /etc/hosts and put fake addresses there.
1220 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse);
1221
1222 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class.
1223 if (!RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse);
1224 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse);
1225
1226 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname));
1227 }
1228
1229 mDNSexport mDNSBool AnyTypeRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q)
1230 {
1231 if (rr->InterfaceID &&
1232 q ->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly &&
1233 rr->InterfaceID != q->InterfaceID) return(mDNSfalse);
1234
1235 // Resource record received via unicast, the DNSServer entries should match ?
1236 // Note that Auth Records are normally setup with NULL InterfaceID and
1237 // both the DNSServers are assumed to be NULL in that case
1238 if (!rr->InterfaceID && rr->rDNSServer != q->qDNSServer) return(mDNSfalse);
1239
1240 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question
1241 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse);
1242
1243 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse);
1244
1245 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname));
1246 }
1247
1248 // This is called only when the caller knows that it is a Unicast Resource Record and it is a Unicast Question
1249 // and hence we don't need InterfaceID checks like above. Though this may not be a big optimization, the main
1250 // reason we need this is that we can't compare DNSServers between the question and the resource record because
1251 // the resource record may not be completely initialized e.g., mDNSCoreReceiveResponse
1252 mDNSexport mDNSBool UnicastResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q)
1253 {
1254 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class.
1255 if (!RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse);
1256
1257 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse);
1258
1259 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname));
1260 }
1261
1262 mDNSexport mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate)
1263 {
1264 const RDataBody2 *const rd = (RDataBody2 *)rr->rdata->u.data;
1265 const domainname *const name = estimate ? rr->name : mDNSNULL;
1266 if (rr->rrclass == kDNSQClass_ANY) return(rr->rdlength); // Used in update packets to mean "Delete An RRset" (RFC 2136)
1267 else switch (rr->rrtype)
1268 {
1269 case kDNSType_A: return(sizeof(rd->ipv4));
1270
1271 case kDNSType_NS:
1272 case kDNSType_CNAME:
1273 case kDNSType_PTR:
1274 case kDNSType_DNAME:return(CompressedDomainNameLength(&rd->name, name));
1275
1276 case kDNSType_SOA: return(mDNSu16)(CompressedDomainNameLength(&rd->soa.mname, name) +
1277 CompressedDomainNameLength(&rd->soa.rname, name) +
1278 5 * sizeof(mDNSOpaque32));
1279
1280 case kDNSType_NULL:
1281 case kDNSType_TSIG:
1282 case kDNSType_TXT:
1283 case kDNSType_X25:
1284 case kDNSType_ISDN:
1285 case kDNSType_LOC:
1286 case kDNSType_DHCID:return(rr->rdlength); // Not self-describing, so have to just trust rdlength
1287
1288 case kDNSType_HINFO:return(mDNSu16)(2 + (int)rd->data[0] + (int)rd->data[1 + (int)rd->data[0]]);
1289
1290 case kDNSType_MX:
1291 case kDNSType_AFSDB:
1292 case kDNSType_RT:
1293 case kDNSType_KX: return(mDNSu16)(2 + CompressedDomainNameLength(&rd->mx.exchange, name));
1294
1295 case kDNSType_RP: return(mDNSu16)(CompressedDomainNameLength(&rd->rp.mbox, name) +
1296 CompressedDomainNameLength(&rd->rp.txt, name));
1297
1298 case kDNSType_PX: return(mDNSu16)(2 + CompressedDomainNameLength(&rd->px.map822, name) +
1299 CompressedDomainNameLength(&rd->px.mapx400, name));
1300
1301 case kDNSType_AAAA: return(sizeof(rd->ipv6));
1302
1303 case kDNSType_SRV: return(mDNSu16)(6 + CompressedDomainNameLength(&rd->srv.target, name));
1304
1305 case kDNSType_OPT: return(rr->rdlength);
1306
1307 case kDNSType_NSEC: {
1308 int i;
1309 for (i=sizeof(rdataNSEC); i>0; i--) if (rd->nsec.bitmap[i-1]) break;
1310 // For our simplified use of NSEC synthetic records:
1311 // nextname is always the record's own name,
1312 // and if we have at least one record type that exists,
1313 // - the block number is always 0,
1314 // - the count byte is a value in the range 1-32,
1315 // - followed by the 1-32 data bytes
1316 return(mDNSu16)((estimate ? 2 : DomainNameLength(rr->name)) + (i ? (2 + i) : 0));
1317 }
1318
1319 default: debugf("Warning! Don't know how to get length of resource type %d", rr->rrtype);
1320 return(rr->rdlength);
1321 }
1322 }
1323
1324 // When a local client registers (or updates) a record, we use this routine to do some simple validation checks
1325 // to help reduce the risk of bogus malformed data on the network
1326 mDNSexport mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd)
1327 {
1328 mDNSu16 len;
1329
1330 switch(rrtype)
1331 {
1332 case kDNSType_A: return(rdlength == sizeof(mDNSv4Addr));
1333
1334 case kDNSType_NS: // Same as PTR
1335 case kDNSType_MD: // Same as PTR
1336 case kDNSType_MF: // Same as PTR
1337 case kDNSType_CNAME:// Same as PTR
1338 //case kDNSType_SOA not checked
1339 case kDNSType_MB: // Same as PTR
1340 case kDNSType_MG: // Same as PTR
1341 case kDNSType_MR: // Same as PTR
1342 //case kDNSType_NULL not checked (no specified format, so always valid)
1343 //case kDNSType_WKS not checked
1344 case kDNSType_PTR: len = DomainNameLengthLimit(&rd->u.name, rd->u.data + rdlength);
1345 return(len <= MAX_DOMAIN_NAME && rdlength == len);
1346
1347 case kDNSType_HINFO:// Same as TXT (roughly)
1348 case kDNSType_MINFO:// Same as TXT (roughly)
1349 case kDNSType_TXT: if (!rdlength) return(mDNSfalse); // TXT record has to be at least one byte (RFC 1035)
1350 {
1351 const mDNSu8 *ptr = rd->u.txt.c;
1352 const mDNSu8 *end = rd->u.txt.c + rdlength;
1353 while (ptr < end) ptr += 1 + ptr[0];
1354 return (ptr == end);
1355 }
1356
1357 case kDNSType_AAAA: return(rdlength == sizeof(mDNSv6Addr));
1358
1359 case kDNSType_MX: // Must be at least two-byte preference, plus domainname
1360 // Call to DomainNameLengthLimit() implicitly enforces both requirements for us
1361 len = DomainNameLengthLimit(&rd->u.mx.exchange, rd->u.data + rdlength);
1362 return(len <= MAX_DOMAIN_NAME && rdlength == 2+len);
1363
1364 case kDNSType_SRV: // Must be at least priority+weight+port, plus domainname
1365 // Call to DomainNameLengthLimit() implicitly enforces both requirements for us
1366 len = DomainNameLengthLimit(&rd->u.srv.target, rd->u.data + rdlength);
1367 return(len <= MAX_DOMAIN_NAME && rdlength == 6+len);
1368
1369 //case kDNSType_NSEC not checked
1370
1371 default: return(mDNStrue); // Allow all other types without checking
1372 }
1373 }
1374
1375 // ***************************************************************************
1376 #if COMPILER_LIKES_PRAGMA_MARK
1377 #pragma mark -
1378 #pragma mark - DNS Message Creation Functions
1379 #endif
1380
1381 mDNSexport void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags)
1382 {
1383 h->id = id;
1384 h->flags = flags;
1385 h->numQuestions = 0;
1386 h->numAnswers = 0;
1387 h->numAuthorities = 0;
1388 h->numAdditionals = 0;
1389 }
1390
1391 mDNSexport const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname)
1392 {
1393 const mDNSu8 *result = end - *domname - 1;
1394
1395 if (*domname == 0) return(mDNSNULL); // There's no point trying to match just the root label
1396
1397 // This loop examines each possible starting position in packet, starting end of the packet and working backwards
1398 while (result >= base)
1399 {
1400 // If the length byte and first character of the label match, then check further to see
1401 // if this location in the packet will yield a useful name compression pointer.
1402 if (result[0] == domname[0] && result[1] == domname[1])
1403 {
1404 const mDNSu8 *name = domname;
1405 const mDNSu8 *targ = result;
1406 while (targ + *name < end)
1407 {
1408 // First see if this label matches
1409 int i;
1410 const mDNSu8 *pointertarget;
1411 for (i=0; i <= *name; i++) if (targ[i] != name[i]) break;
1412 if (i <= *name) break; // If label did not match, bail out
1413 targ += 1 + *name; // Else, did match, so advance target pointer
1414 name += 1 + *name; // and proceed to check next label
1415 if (*name == 0 && *targ == 0) return(result); // If no more labels, we found a match!
1416 if (*name == 0) break; // If no more labels to match, we failed, so bail out
1417
1418 // The label matched, so now follow the pointer (if appropriate) and then see if the next label matches
1419 if (targ[0] < 0x40) continue; // If length value, continue to check next label
1420 if (targ[0] < 0xC0) break; // If 40-BF, not valid
1421 if (targ+1 >= end) break; // Second byte not present!
1422 pointertarget = base + (((mDNSu16)(targ[0] & 0x3F)) << 8) + targ[1];
1423 if (targ < pointertarget) break; // Pointertarget must point *backwards* in the packet
1424 if (pointertarget[0] >= 0x40) break; // Pointertarget must point to a valid length byte
1425 targ = pointertarget;
1426 }
1427 }
1428 result--; // We failed to match at this search position, so back up the tentative result pointer and try again
1429 }
1430 return(mDNSNULL);
1431 }
1432
1433 // Put a string of dot-separated labels as length-prefixed labels
1434 // domainname is a fully-qualified name (i.e. assumed to be ending in a dot, even if it doesn't)
1435 // msg points to the message we're building (pass mDNSNULL if we don't want to use compression pointers)
1436 // end points to the end of the message so far
1437 // ptr points to where we want to put the name
1438 // limit points to one byte past the end of the buffer that we must not overrun
1439 // domainname is the name to put
1440 mDNSexport mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg,
1441 mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name)
1442 {
1443 const mDNSu8 *const base = (const mDNSu8 *)msg;
1444 const mDNSu8 * np = name->c;
1445 const mDNSu8 *const max = name->c + MAX_DOMAIN_NAME; // Maximum that's valid
1446 const mDNSu8 * pointer = mDNSNULL;
1447 const mDNSu8 *const searchlimit = ptr;
1448
1449 if (!ptr) { LogMsg("putDomainNameAsLabels %##s ptr is null", name->c); return(mDNSNULL); }
1450
1451 if (!*np) // If just writing one-byte root label, make sure we have space for that
1452 {
1453 if (ptr >= limit) return(mDNSNULL);
1454 }
1455 else // else, loop through writing labels and/or a compression offset
1456 {
1457 do {
1458 if (*np > MAX_DOMAIN_LABEL)
1459 { LogMsg("Malformed domain name %##s (label more than 63 bytes)", name->c); return(mDNSNULL); }
1460
1461 // This check correctly allows for the final trailing root label:
1462 // e.g.
1463 // Suppose our domain name is exactly 256 bytes long, including the final trailing root label.
1464 // Suppose np is now at name->c[249], and we're about to write our last non-null label ("local").
1465 // We know that max will be at name->c[256]
1466 // That means that np + 1 + 5 == max - 1, so we (just) pass the "if" test below, write our
1467 // six bytes, then exit the loop, write the final terminating root label, and the domain
1468 // name we've written is exactly 256 bytes long, exactly at the correct legal limit.
1469 // If the name is one byte longer, then we fail the "if" test below, and correctly bail out.
1470 if (np + 1 + *np >= max)
1471 { LogMsg("Malformed domain name %##s (more than 256 bytes)", name->c); return(mDNSNULL); }
1472
1473 if (base) pointer = FindCompressionPointer(base, searchlimit, np);
1474 if (pointer) // Use a compression pointer if we can
1475 {
1476 const mDNSu16 offset = (mDNSu16)(pointer - base);
1477 if (ptr+2 > limit) return(mDNSNULL); // If we don't have two bytes of space left, give up
1478 *ptr++ = (mDNSu8)(0xC0 | (offset >> 8));
1479 *ptr++ = (mDNSu8)( offset & 0xFF);
1480 return(ptr);
1481 }
1482 else // Else copy one label and try again
1483 {
1484 int i;
1485 mDNSu8 len = *np++;
1486 // If we don't at least have enough space for this label *plus* a terminating zero on the end, give up
1487 if (ptr + 1 + len >= limit) return(mDNSNULL);
1488 *ptr++ = len;
1489 for (i=0; i<len; i++) *ptr++ = *np++;
1490 }
1491 } while (*np); // While we've got characters remaining in the name, continue
1492 }
1493
1494 *ptr++ = 0; // Put the final root label
1495 return(ptr);
1496 }
1497
1498 mDNSlocal mDNSu8 *putVal16(mDNSu8 *ptr, mDNSu16 val)
1499 {
1500 ptr[0] = (mDNSu8)((val >> 8 ) & 0xFF);
1501 ptr[1] = (mDNSu8)((val ) & 0xFF);
1502 return ptr + sizeof(mDNSOpaque16);
1503 }
1504
1505 mDNSlocal mDNSu8 *putVal32(mDNSu8 *ptr, mDNSu32 val)
1506 {
1507 ptr[0] = (mDNSu8)((val >> 24) & 0xFF);
1508 ptr[1] = (mDNSu8)((val >> 16) & 0xFF);
1509 ptr[2] = (mDNSu8)((val >> 8) & 0xFF);
1510 ptr[3] = (mDNSu8)((val ) & 0xFF);
1511 return ptr + sizeof(mDNSu32);
1512 }
1513
1514 // msg points to the message we're building (pass mDNSNULL if we don't want to use compression pointers)
1515 mDNSexport mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr)
1516 {
1517 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data;
1518 switch (rr->rrtype)
1519 {
1520 case kDNSType_A: if (rr->rdlength != 4)
1521 { debugf("putRData: Illegal length %d for kDNSType_A", rr->rdlength); return(mDNSNULL); }
1522 if (ptr + 4 > limit) return(mDNSNULL);
1523 *ptr++ = rdb->ipv4.b[0];
1524 *ptr++ = rdb->ipv4.b[1];
1525 *ptr++ = rdb->ipv4.b[2];
1526 *ptr++ = rdb->ipv4.b[3];
1527 return(ptr);
1528
1529 case kDNSType_NS:
1530 case kDNSType_CNAME:
1531 case kDNSType_PTR:
1532 case kDNSType_DNAME:return(putDomainNameAsLabels(msg, ptr, limit, &rdb->name));
1533
1534 case kDNSType_SOA: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.mname);
1535 if (!ptr) return(mDNSNULL);
1536 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.rname);
1537 if (!ptr || ptr + 20 > limit) return(mDNSNULL);
1538 ptr = putVal32(ptr, rdb->soa.serial);
1539 ptr = putVal32(ptr, rdb->soa.refresh);
1540 ptr = putVal32(ptr, rdb->soa.retry);
1541 ptr = putVal32(ptr, rdb->soa.expire);
1542 ptr = putVal32(ptr, rdb->soa.min);
1543 return(ptr);
1544
1545 case kDNSType_NULL:
1546 case kDNSType_HINFO:
1547 case kDNSType_TSIG:
1548 case kDNSType_TXT:
1549 case kDNSType_X25:
1550 case kDNSType_ISDN:
1551 case kDNSType_LOC:
1552 case kDNSType_DHCID:if (ptr + rr->rdlength > limit) return(mDNSNULL);
1553 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength);
1554 return(ptr + rr->rdlength);
1555
1556 case kDNSType_MX:
1557 case kDNSType_AFSDB:
1558 case kDNSType_RT:
1559 case kDNSType_KX: if (ptr + 3 > limit) return(mDNSNULL);
1560 ptr = putVal16(ptr, rdb->mx.preference);
1561 return(putDomainNameAsLabels(msg, ptr, limit, &rdb->mx.exchange));
1562
1563 case kDNSType_RP: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.mbox);
1564 if (!ptr) return(mDNSNULL);
1565 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.txt);
1566 return(ptr);
1567
1568 case kDNSType_PX: if (ptr + 5 > limit) return(mDNSNULL);
1569 ptr = putVal16(ptr, rdb->px.preference);
1570 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.map822);
1571 if (!ptr) return(mDNSNULL);
1572 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.mapx400);
1573 return(ptr);
1574
1575 case kDNSType_AAAA: if (rr->rdlength != sizeof(rdb->ipv6))
1576 { debugf("putRData: Illegal length %d for kDNSType_AAAA", rr->rdlength); return(mDNSNULL); }
1577 if (ptr + sizeof(rdb->ipv6) > limit) return(mDNSNULL);
1578 mDNSPlatformMemCopy(ptr, &rdb->ipv6, sizeof(rdb->ipv6));
1579 return(ptr + sizeof(rdb->ipv6));
1580
1581 case kDNSType_SRV: if (ptr + 7 > limit) return(mDNSNULL);
1582 *ptr++ = (mDNSu8)(rdb->srv.priority >> 8);
1583 *ptr++ = (mDNSu8)(rdb->srv.priority & 0xFF);
1584 *ptr++ = (mDNSu8)(rdb->srv.weight >> 8);
1585 *ptr++ = (mDNSu8)(rdb->srv.weight & 0xFF);
1586 *ptr++ = rdb->srv.port.b[0];
1587 *ptr++ = rdb->srv.port.b[1];
1588 return(putDomainNameAsLabels(msg, ptr, limit, &rdb->srv.target));
1589
1590 case kDNSType_OPT: {
1591 int len = 0;
1592 const rdataOPT *opt;
1593 const rdataOPT *const end = (const rdataOPT *)&rr->rdata->u.data[rr->rdlength];
1594 for (opt = &rr->rdata->u.opt[0]; opt < end; opt++) len += DNSOpt_Data_Space(opt);
1595 if (ptr + len > limit) { LogMsg("ERROR: putOptRData - out of space"); return mDNSNULL; }
1596
1597 for (opt = &rr->rdata->u.opt[0]; opt < end; opt++)
1598 {
1599 const int space = DNSOpt_Data_Space(opt);
1600 ptr = putVal16(ptr, opt->opt);
1601 ptr = putVal16(ptr, (mDNSu16)space - 4);
1602 switch (opt->opt)
1603 {
1604 case kDNSOpt_LLQ:
1605 ptr = putVal16(ptr, opt->u.llq.vers);
1606 ptr = putVal16(ptr, opt->u.llq.llqOp);
1607 ptr = putVal16(ptr, opt->u.llq.err);
1608 mDNSPlatformMemCopy(ptr, opt->u.llq.id.b, 8); // 8-byte id
1609 ptr += 8;
1610 ptr = putVal32(ptr, opt->u.llq.llqlease);
1611 break;
1612 case kDNSOpt_Lease:
1613 ptr = putVal32(ptr, opt->u.updatelease);
1614 break;
1615 case kDNSOpt_Owner:
1616 *ptr++ = opt->u.owner.vers;
1617 *ptr++ = opt->u.owner.seq;
1618 mDNSPlatformMemCopy(ptr, opt->u.owner.HMAC.b, 6); // 6-byte Host identifier
1619 ptr += 6;
1620 if (space >= DNSOpt_OwnerData_ID_Wake_Space)
1621 {
1622 mDNSPlatformMemCopy(ptr, opt->u.owner.IMAC.b, 6); // 6-byte interface MAC
1623 ptr += 6;
1624 if (space > DNSOpt_OwnerData_ID_Wake_Space)
1625 {
1626 mDNSPlatformMemCopy(ptr, opt->u.owner.password.b, space - DNSOpt_OwnerData_ID_Wake_Space);
1627 ptr += space - DNSOpt_OwnerData_ID_Wake_Space;
1628 }
1629 }
1630 break;
1631 }
1632 }
1633 return ptr;
1634 }
1635
1636 case kDNSType_NSEC: {
1637 // For our simplified use of NSEC synthetic records:
1638 // nextname is always the record's own name,
1639 // the block number is always 0,
1640 // the count byte is a value in the range 1-32,
1641 // followed by the 1-32 data bytes
1642 int i, j;
1643 for (i=sizeof(rdataNSEC); i>0; i--) if (rdb->nsec.bitmap[i-1]) break;
1644 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name);
1645 if (!ptr) return(mDNSNULL);
1646 if (i) // Only put a block if at least one type exists for this name
1647 {
1648 if (ptr + 2 + i > limit) return(mDNSNULL);
1649 *ptr++ = 0;
1650 *ptr++ = (mDNSu8)i;
1651 for (j=0; j<i; j++) *ptr++ = rdb->nsec.bitmap[j];
1652 }
1653 return ptr;
1654 }
1655
1656 default: debugf("putRData: Warning! Writing unknown resource type %d as raw data", rr->rrtype);
1657 if (ptr + rr->rdlength > limit) return(mDNSNULL);
1658 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength);
1659 return(ptr + rr->rdlength);
1660 }
1661 }
1662
1663 #define IsUnicastUpdate(X) (!mDNSOpaque16IsZero((X)->h.id) && ((X)->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update)
1664
1665 mDNSexport mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit)
1666 {
1667 mDNSu8 *endofrdata;
1668 mDNSu16 actualLength;
1669 // When sending SRV to conventional DNS server (i.e. in DNS update requests) we should not do name compression on the rdata (RFC 2782)
1670 const DNSMessage *const rdatacompressionbase = (IsUnicastUpdate(msg) && rr->rrtype == kDNSType_SRV) ? mDNSNULL : msg;
1671
1672 if (rr->RecordType == kDNSRecordTypeUnregistered)
1673 {
1674 LogMsg("PutResourceRecord ERROR! Attempt to put kDNSRecordTypeUnregistered %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype));
1675 return(ptr);
1676 }
1677
1678 if (!ptr) { LogMsg("PutResourceRecordTTLWithLimit ptr is null"); return(mDNSNULL); }
1679
1680 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name);
1681 if (!ptr || ptr + 10 >= limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL
1682 ptr[0] = (mDNSu8)(rr->rrtype >> 8);
1683 ptr[1] = (mDNSu8)(rr->rrtype & 0xFF);
1684 ptr[2] = (mDNSu8)(rr->rrclass >> 8);
1685 ptr[3] = (mDNSu8)(rr->rrclass & 0xFF);
1686 ptr[4] = (mDNSu8)((ttl >> 24) & 0xFF);
1687 ptr[5] = (mDNSu8)((ttl >> 16) & 0xFF);
1688 ptr[6] = (mDNSu8)((ttl >> 8) & 0xFF);
1689 ptr[7] = (mDNSu8)( ttl & 0xFF);
1690 // ptr[8] and ptr[9] filled in *after* we find out how much space the rdata takes
1691
1692 endofrdata = putRData(rdatacompressionbase, ptr+10, limit, rr);
1693 if (!endofrdata) { verbosedebugf("Ran out of space in PutResourceRecord for %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); return(mDNSNULL); }
1694
1695 // Go back and fill in the actual number of data bytes we wrote
1696 // (actualLength can be less than rdlength when domain name compression is used)
1697 actualLength = (mDNSu16)(endofrdata - ptr - 10);
1698 ptr[8] = (mDNSu8)(actualLength >> 8);
1699 ptr[9] = (mDNSu8)(actualLength & 0xFF);
1700
1701 if (count) (*count)++;
1702 else LogMsg("PutResourceRecordTTL: ERROR: No target count to update for %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype));
1703 return(endofrdata);
1704 }
1705
1706 mDNSlocal mDNSu8 *putEmptyResourceRecord(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, mDNSu16 *count, const AuthRecord *rr)
1707 {
1708 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->resrec.name);
1709 if (!ptr || ptr + 10 > limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL
1710 ptr[0] = (mDNSu8)(rr->resrec.rrtype >> 8); // Put type
1711 ptr[1] = (mDNSu8)(rr->resrec.rrtype & 0xFF);
1712 ptr[2] = (mDNSu8)(rr->resrec.rrclass >> 8); // Put class
1713 ptr[3] = (mDNSu8)(rr->resrec.rrclass & 0xFF);
1714 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // TTL is zero
1715 ptr[8] = ptr[9] = 0; // RDATA length is zero
1716 (*count)++;
1717 return(ptr + 10);
1718 }
1719
1720 mDNSexport mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass)
1721 {
1722 ptr = putDomainNameAsLabels(msg, ptr, limit, name);
1723 if (!ptr || ptr+4 >= limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL
1724 ptr[0] = (mDNSu8)(rrtype >> 8);
1725 ptr[1] = (mDNSu8)(rrtype & 0xFF);
1726 ptr[2] = (mDNSu8)(rrclass >> 8);
1727 ptr[3] = (mDNSu8)(rrclass & 0xFF);
1728 msg->h.numQuestions++;
1729 return(ptr+4);
1730 }
1731
1732 // for dynamic updates
1733 mDNSexport mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass)
1734 {
1735 ptr = putDomainNameAsLabels(msg, ptr, limit, zone);
1736 if (!ptr || ptr + 4 > limit) return mDNSNULL; // If we're out-of-space, return NULL
1737 *ptr++ = (mDNSu8)(kDNSType_SOA >> 8);
1738 *ptr++ = (mDNSu8)(kDNSType_SOA & 0xFF);
1739 *ptr++ = zoneClass.b[0];
1740 *ptr++ = zoneClass.b[1];
1741 msg->h.mDNS_numZones++;
1742 return ptr;
1743 }
1744
1745 // for dynamic updates
1746 mDNSexport mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *const msg, mDNSu8 *const ptr, mDNSu8 *const end)
1747 {
1748 AuthRecord prereq;
1749 mDNS_SetupResourceRecord(&prereq, mDNSNULL, mDNSInterface_Any, kDNSQType_ANY, kStandardTTL, 0, mDNSNULL, mDNSNULL);
1750 AssignDomainName(&prereq.namestorage, name);
1751 prereq.resrec.rrtype = kDNSQType_ANY;
1752 prereq.resrec.rrclass = kDNSClass_NONE;
1753 return putEmptyResourceRecord(msg, ptr, end, &msg->h.mDNS_numPrereqs, &prereq);
1754 }
1755
1756 // for dynamic updates
1757 mDNSexport mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr)
1758 {
1759 // deletion: specify record w/ TTL 0, class NONE
1760 const mDNSu16 origclass = rr->rrclass;
1761 rr->rrclass = kDNSClass_NONE;
1762 ptr = PutResourceRecordTTLJumbo(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0);
1763 rr->rrclass = origclass;
1764 return ptr;
1765 }
1766
1767 // for dynamic updates
1768 mDNSexport mDNSu8 *putDeletionRecordWithLimit(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr, mDNSu8 *limit)
1769 {
1770 // deletion: specify record w/ TTL 0, class NONE
1771 const mDNSu16 origclass = rr->rrclass;
1772 rr->rrclass = kDNSClass_NONE;
1773 ptr = PutResourceRecordTTLWithLimit(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0, limit);
1774 rr->rrclass = origclass;
1775 return ptr;
1776 }
1777
1778 mDNSexport mDNSu8 *putDeleteRRSetWithLimit(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype, mDNSu8 *limit)
1779 {
1780 mDNSu16 class = kDNSQClass_ANY;
1781
1782 ptr = putDomainNameAsLabels(msg, ptr, limit, name);
1783 if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL
1784 ptr[0] = (mDNSu8)(rrtype >> 8);
1785 ptr[1] = (mDNSu8)(rrtype & 0xFF);
1786 ptr[2] = (mDNSu8)(class >> 8);
1787 ptr[3] = (mDNSu8)(class & 0xFF);
1788 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl
1789 ptr[8] = ptr[9] = 0; // zero rdlength/rdata
1790
1791 msg->h.mDNS_numUpdates++;
1792 return ptr + 10;
1793 }
1794
1795 // for dynamic updates
1796 mDNSexport mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name)
1797 {
1798 const mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData;
1799 mDNSu16 class = kDNSQClass_ANY;
1800 mDNSu16 rrtype = kDNSQType_ANY;
1801
1802 ptr = putDomainNameAsLabels(msg, ptr, limit, name);
1803 if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL
1804 ptr[0] = (mDNSu8)(rrtype >> 8);
1805 ptr[1] = (mDNSu8)(rrtype & 0xFF);
1806 ptr[2] = (mDNSu8)(class >> 8);
1807 ptr[3] = (mDNSu8)(class & 0xFF);
1808 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl
1809 ptr[8] = ptr[9] = 0; // zero rdlength/rdata
1810
1811 msg->h.mDNS_numUpdates++;
1812 return ptr + 10;
1813 }
1814
1815 // for dynamic updates
1816 mDNSexport mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease)
1817 {
1818 AuthRecord rr;
1819 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, mDNSNULL, mDNSNULL);
1820 rr.resrec.rrclass = NormalMaxDNSMessageData;
1821 rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record
1822 rr.resrec.rdestimate = sizeof(rdataOPT);
1823 rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease;
1824 rr.resrec.rdata->u.opt[0].u.updatelease = lease;
1825 end = PutResourceRecordTTLJumbo(msg, end, &msg->h.numAdditionals, &rr.resrec, 0);
1826 if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTL"); return mDNSNULL; }
1827 return end;
1828 }
1829
1830 // for dynamic updates
1831 mDNSexport mDNSu8 *putUpdateLeaseWithLimit(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease, mDNSu8 *limit)
1832 {
1833 AuthRecord rr;
1834 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, mDNSNULL, mDNSNULL);
1835 rr.resrec.rrclass = NormalMaxDNSMessageData;
1836 rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record
1837 rr.resrec.rdestimate = sizeof(rdataOPT);
1838 rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease;
1839 rr.resrec.rdata->u.opt[0].u.updatelease = lease;
1840 end = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &rr.resrec, 0, limit);
1841 if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTLWithLimit"); return mDNSNULL; }
1842 return end;
1843 }
1844
1845 mDNSexport mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *end, DomainAuthInfo *authInfo, mDNSu8 *limit)
1846 {
1847 if (authInfo && authInfo->AutoTunnel)
1848 {
1849 AuthRecord hinfo;
1850 mDNSu8 *h = hinfo.rdatastorage.u.data;
1851 mDNSu16 len = 2 + m->HIHardware.c[0] + m->HISoftware.c[0];
1852 mDNSu8 *newptr;
1853 mDNS_SetupResourceRecord(&hinfo, mDNSNULL, mDNSInterface_Any, kDNSType_HINFO, 0, kDNSRecordTypeUnique, mDNSNULL, mDNSNULL);
1854 AppendDomainLabel(&hinfo.namestorage, &m->hostlabel);
1855 AppendDomainName (&hinfo.namestorage, &authInfo->domain);
1856 hinfo.resrec.rroriginalttl = 0;
1857 mDNSPlatformMemCopy(h, &m->HIHardware, 1 + (mDNSu32)m->HIHardware.c[0]);
1858 h += 1 + (int)h[0];
1859 mDNSPlatformMemCopy(h, &m->HISoftware, 1 + (mDNSu32)m->HISoftware.c[0]);
1860 hinfo.resrec.rdlength = len;
1861 hinfo.resrec.rdestimate = len;
1862 newptr = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &hinfo.resrec, 0, limit);
1863 return newptr;
1864 }
1865 else
1866 return end;
1867 }
1868
1869 // ***************************************************************************
1870 #if COMPILER_LIKES_PRAGMA_MARK
1871 #pragma mark -
1872 #pragma mark - DNS Message Parsing Functions
1873 #endif
1874
1875 mDNSexport mDNSu32 DomainNameHashValue(const domainname *const name)
1876 {
1877 mDNSu32 sum = 0;
1878 const mDNSu8 *c;
1879
1880 for (c = name->c; c[0] != 0 && c[1] != 0; c += 2)
1881 {
1882 sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8) |
1883 (mDNSIsUpperCase(c[1]) ? c[1] + 'a' - 'A' : c[1]);
1884 sum = (sum<<3) | (sum>>29);
1885 }
1886 if (c[0]) sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8);
1887 return(sum);
1888 }
1889
1890 mDNSexport void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength)
1891 {
1892 domainname *target;
1893 if (NewRData)
1894 {
1895 rr->rdata = NewRData;
1896 rr->rdlength = rdlength;
1897 }
1898 // Must not try to get target pointer until after updating rr->rdata
1899 target = GetRRDomainNameTarget(rr);
1900 rr->rdlength = GetRDLength(rr, mDNSfalse);
1901 rr->rdestimate = GetRDLength(rr, mDNStrue);
1902 rr->rdatahash = target ? DomainNameHashValue(target) : RDataHashValue(rr);
1903 }
1904
1905 mDNSexport const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end)
1906 {
1907 mDNSu16 total = 0;
1908
1909 if (ptr < (mDNSu8*)msg || ptr >= end)
1910 { debugf("skipDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); }
1911
1912 while (1) // Read sequence of labels
1913 {
1914 const mDNSu8 len = *ptr++; // Read length of this label
1915 if (len == 0) return(ptr); // If length is zero, that means this name is complete
1916 switch (len & 0xC0)
1917 {
1918 case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label
1919 { debugf("skipDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); }
1920 if (total + 1 + len >= MAX_DOMAIN_NAME) // Remember: expect at least one more byte for the root label
1921 { debugf("skipDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); }
1922 ptr += len;
1923 total += 1 + len;
1924 break;
1925
1926 case 0x40: debugf("skipDomainName: Extended EDNS0 label types 0x%X not supported", len); return(mDNSNULL);
1927 case 0x80: debugf("skipDomainName: Illegal label length 0x%X", len); return(mDNSNULL);
1928 case 0xC0: return(ptr+1);
1929 }
1930 }
1931 }
1932
1933 // Routine to fetch an FQDN from the DNS message, following compression pointers if necessary.
1934 mDNSexport const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end,
1935 domainname *const name)
1936 {
1937 const mDNSu8 *nextbyte = mDNSNULL; // Record where we got to before we started following pointers
1938 mDNSu8 *np = name->c; // Name pointer
1939 const mDNSu8 *const limit = np + MAX_DOMAIN_NAME; // Limit so we don't overrun buffer
1940
1941 if (ptr < (mDNSu8*)msg || ptr >= end)
1942 { debugf("getDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); }
1943
1944 *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels)
1945
1946 while (1) // Read sequence of labels
1947 {
1948 const mDNSu8 len = *ptr++; // Read length of this label
1949 if (len == 0) break; // If length is zero, that means this name is complete
1950 switch (len & 0xC0)
1951 {
1952 int i;
1953 mDNSu16 offset;
1954
1955 case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label
1956 { debugf("getDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); }
1957 if (np + 1 + len >= limit) // Remember: expect at least one more byte for the root label
1958 { debugf("getDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); }
1959 *np++ = len;
1960 for (i=0; i<len; i++) *np++ = *ptr++;
1961 *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels)
1962 break;
1963
1964 case 0x40: debugf("getDomainName: Extended EDNS0 label types 0x%X not supported in name %##s", len, name->c);
1965 return(mDNSNULL);
1966
1967 case 0x80: debugf("getDomainName: Illegal label length 0x%X in domain name %##s", len, name->c); return(mDNSNULL);
1968
1969 case 0xC0: offset = (mDNSu16)((((mDNSu16)(len & 0x3F)) << 8) | *ptr++);
1970 if (!nextbyte) nextbyte = ptr; // Record where we got to before we started following pointers
1971 ptr = (mDNSu8 *)msg + offset;
1972 if (ptr < (mDNSu8*)msg || ptr >= end)
1973 { debugf("getDomainName: Illegal compression pointer not within packet boundaries"); return(mDNSNULL); }
1974 if (*ptr & 0xC0)
1975 { debugf("getDomainName: Compression pointer must point to real label"); return(mDNSNULL); }
1976 break;
1977 }
1978 }
1979
1980 if (nextbyte) return(nextbyte);
1981 else return(ptr);
1982 }
1983
1984 mDNSexport const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end)
1985 {
1986 mDNSu16 pktrdlength;
1987
1988 ptr = skipDomainName(msg, ptr, end);
1989 if (!ptr) { debugf("skipResourceRecord: Malformed RR name"); return(mDNSNULL); }
1990
1991 if (ptr + 10 > end) { debugf("skipResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); }
1992 pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]);
1993 ptr += 10;
1994 if (ptr + pktrdlength > end) { debugf("skipResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); }
1995
1996 return(ptr + pktrdlength);
1997 }
1998
1999 mDNSexport const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr,
2000 const mDNSu8 *end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *const largecr)
2001 {
2002 CacheRecord *const rr = &largecr->r;
2003 RDataBody2 *const rdb = (RDataBody2 *)rr->smallrdatastorage.data;
2004 mDNSu16 pktrdlength;
2005
2006 if (largecr == &m->rec && m->rec.r.resrec.RecordType)
2007 {
2008 LogMsg("GetLargeResourceRecord: m->rec appears to be already in use for %s", CRDisplayString(m, &m->rec.r));
2009 #if ForceAlerts
2010 *(long*)0 = 0;
2011 #endif
2012 }
2013
2014 rr->next = mDNSNULL;
2015 rr->resrec.name = &largecr->namestorage;
2016
2017 rr->NextInKAList = mDNSNULL;
2018 rr->TimeRcvd = m ? m->timenow : 0;
2019 rr->DelayDelivery = 0;
2020 rr->NextRequiredQuery = m ? m->timenow : 0; // Will be updated to the real value when we call SetNextCacheCheckTimeForRecord()
2021 rr->LastUsed = m ? m->timenow : 0;
2022 rr->CRActiveQuestion = mDNSNULL;
2023 rr->UnansweredQueries = 0;
2024 rr->LastUnansweredTime= 0;
2025 #if ENABLE_MULTI_PACKET_QUERY_SNOOPING
2026 rr->MPUnansweredQ = 0;
2027 rr->MPLastUnansweredQT= 0;
2028 rr->MPUnansweredKA = 0;
2029 rr->MPExpectingKA = mDNSfalse;
2030 #endif
2031 rr->NextInCFList = mDNSNULL;
2032
2033 rr->resrec.InterfaceID = InterfaceID;
2034 rr->resrec.rDNSServer = mDNSNULL;
2035
2036 ptr = getDomainName(msg, ptr, end, &largecr->namestorage); // Will bail out correctly if ptr is NULL
2037 if (!ptr) { debugf("GetLargeResourceRecord: Malformed RR name"); return(mDNSNULL); }
2038 rr->resrec.namehash = DomainNameHashValue(rr->resrec.name);
2039
2040 if (ptr + 10 > end) { debugf("GetLargeResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); }
2041
2042 rr->resrec.rrtype = (mDNSu16) ((mDNSu16)ptr[0] << 8 | ptr[1]);
2043 rr->resrec.rrclass = (mDNSu16)(((mDNSu16)ptr[2] << 8 | ptr[3]) & kDNSClass_Mask);
2044 rr->resrec.rroriginalttl = (mDNSu32) ((mDNSu32)ptr[4] << 24 | (mDNSu32)ptr[5] << 16 | (mDNSu32)ptr[6] << 8 | ptr[7]);
2045 if (rr->resrec.rroriginalttl > 0x70000000UL / mDNSPlatformOneSecond && (mDNSs32)rr->resrec.rroriginalttl != -1)
2046 rr->resrec.rroriginalttl = 0x70000000UL / mDNSPlatformOneSecond;
2047 // Note: We don't have to adjust m->NextCacheCheck here -- this is just getting a record into memory for
2048 // us to look at. If we decide to copy it into the cache, then we'll update m->NextCacheCheck accordingly.
2049 pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]);
2050
2051 // If mDNS record has cache-flush bit set, we mark it unique
2052 // For uDNS records, all are implicitly deemed unique (a single DNS server is always
2053 // authoritative for the entire RRSet), unless this is a truncated response
2054 if (ptr[2] & (kDNSClass_UniqueRRSet >> 8) || (!InterfaceID && !(msg->h.flags.b[0] & kDNSFlag0_TC)))
2055 RecordType |= kDNSRecordTypePacketUniqueMask;
2056 ptr += 10;
2057 if (ptr + pktrdlength > end) { debugf("GetLargeResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); }
2058 end = ptr + pktrdlength; // Adjust end to indicate the end of the rdata for this resource record
2059
2060 rr->resrec.rdata = (RData*)&rr->smallrdatastorage;
2061 rr->resrec.rdata->MaxRDLength = MaximumRDSize;
2062
2063 if (!RecordType) LogMsg("GetLargeResourceRecord: No RecordType for %##s", rr->resrec.name->c);
2064
2065 // IMPORTANT: Any record type we understand and unpack into a structure containing domainnames needs to have corresponding
2066 // cases in SameRDataBody() and RDataHashValue() to do a semantic comparison (or checksum) of the structure instead of a blind
2067 // bitwise memory compare (or sum). This is because a domainname is a fixed size structure holding variable-length data.
2068 // Any bytes past the logical end of the name are undefined, and a blind bitwise memory compare may indicate that
2069 // two domainnames are different when semantically they are the same name and it's only the unused bytes that differ.
2070 if (rr->resrec.rrclass == kDNSQClass_ANY && pktrdlength == 0) // Used in update packets to mean "Delete An RRset" (RFC 2136)
2071 rr->resrec.rdlength = 0;
2072 else switch (rr->resrec.rrtype)
2073 {
2074 case kDNSType_A: if (pktrdlength != sizeof(mDNSv4Addr)) goto fail;
2075 rdb->ipv4.b[0] = ptr[0];
2076 rdb->ipv4.b[1] = ptr[1];
2077 rdb->ipv4.b[2] = ptr[2];
2078 rdb->ipv4.b[3] = ptr[3];
2079 break;
2080
2081 case kDNSType_NS:
2082 case kDNSType_CNAME:
2083 case kDNSType_PTR:
2084 case kDNSType_DNAME:ptr = getDomainName(msg, ptr, end, &rdb->name);
2085 if (ptr != end) { debugf("GetLargeResourceRecord: Malformed CNAME/PTR RDATA name"); goto fail; }
2086 //debugf("%##s PTR %##s rdlen %d", rr->resrec.name.c, rdb->name.c, pktrdlength);
2087 break;
2088
2089 case kDNSType_SOA: ptr = getDomainName(msg, ptr, end, &rdb->soa.mname);
2090 if (!ptr) { debugf("GetLargeResourceRecord: Malformed SOA RDATA mname"); goto fail; }
2091 ptr = getDomainName(msg, ptr, end, &rdb->soa.rname);
2092 if (!ptr) { debugf("GetLargeResourceRecord: Malformed SOA RDATA rname"); goto fail; }
2093 if (ptr + 0x14 != end) { debugf("GetLargeResourceRecord: Malformed SOA RDATA"); goto fail; }
2094 rdb->soa.serial = (mDNSs32) ((mDNSs32)ptr[0x00] << 24 | (mDNSs32)ptr[0x01] << 16 | (mDNSs32)ptr[0x02] << 8 | ptr[0x03]);
2095 rdb->soa.refresh = (mDNSu32) ((mDNSu32)ptr[0x04] << 24 | (mDNSu32)ptr[0x05] << 16 | (mDNSu32)ptr[0x06] << 8 | ptr[0x07]);
2096 rdb->soa.retry = (mDNSu32) ((mDNSu32)ptr[0x08] << 24 | (mDNSu32)ptr[0x09] << 16 | (mDNSu32)ptr[0x0A] << 8 | ptr[0x0B]);
2097 rdb->soa.expire = (mDNSu32) ((mDNSu32)ptr[0x0C] << 24 | (mDNSu32)ptr[0x0D] << 16 | (mDNSu32)ptr[0x0E] << 8 | ptr[0x0F]);
2098 rdb->soa.min = (mDNSu32) ((mDNSu32)ptr[0x10] << 24 | (mDNSu32)ptr[0x11] << 16 | (mDNSu32)ptr[0x12] << 8 | ptr[0x13]);
2099 break;
2100
2101 case kDNSType_NULL:
2102 case kDNSType_HINFO:
2103 case kDNSType_TSIG:
2104 case kDNSType_TXT:
2105 case kDNSType_X25:
2106 case kDNSType_ISDN:
2107 case kDNSType_LOC:
2108 case kDNSType_DHCID:if (pktrdlength > rr->resrec.rdata->MaxRDLength)
2109 {
2110 debugf("GetLargeResourceRecord: %s rdata size (%d) exceeds storage (%d)",
2111 DNSTypeName(rr->resrec.rrtype), pktrdlength, rr->resrec.rdata->MaxRDLength);
2112 goto fail;
2113 }
2114 rr->resrec.rdlength = pktrdlength;
2115 mDNSPlatformMemCopy(rdb->data, ptr, pktrdlength);
2116 break;
2117
2118 case kDNSType_MX:
2119 case kDNSType_AFSDB:
2120 case kDNSType_RT:
2121 case kDNSType_KX: if (pktrdlength < 3) goto fail; // Preference + domainname
2122 rdb->mx.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]);
2123 ptr = getDomainName(msg, ptr+2, end, &rdb->mx.exchange);
2124 if (ptr != end) { debugf("GetLargeResourceRecord: Malformed MX name"); goto fail; }
2125 //debugf("%##s SRV %##s rdlen %d", rr->resrec.name.c, rdb->srv.target.c, pktrdlength);
2126 break;
2127
2128 case kDNSType_RP: ptr = getDomainName(msg, ptr, end, &rdb->rp.mbox); // Domainname + domainname
2129 if (!ptr) { debugf("GetLargeResourceRecord: Malformed RP mbox"); goto fail; }
2130 ptr = getDomainName(msg, ptr, end, &rdb->rp.txt);
2131 if (ptr != end) { debugf("GetLargeResourceRecord: Malformed RP txt"); goto fail; }
2132 break;
2133
2134 case kDNSType_PX: if (pktrdlength < 4) goto fail; // Preference + domainname + domainname
2135 rdb->px.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]);
2136 ptr = getDomainName(msg, ptr, end, &rdb->px.map822);
2137 if (!ptr) { debugf("GetLargeResourceRecord: Malformed PX map822"); goto fail; }
2138 ptr = getDomainName(msg, ptr, end, &rdb->px.mapx400);
2139 if (ptr != end) { debugf("GetLargeResourceRecord: Malformed PX mapx400"); goto fail; }
2140 break;
2141
2142 case kDNSType_AAAA: if (pktrdlength != sizeof(mDNSv6Addr)) goto fail;
2143 mDNSPlatformMemCopy(&rdb->ipv6, ptr, sizeof(rdb->ipv6));
2144 break;
2145
2146 case kDNSType_SRV: if (pktrdlength < 7) goto fail; // Priority + weight + port + domainname
2147 rdb->srv.priority = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]);
2148 rdb->srv.weight = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]);
2149 rdb->srv.port.b[0] = ptr[4];
2150 rdb->srv.port.b[1] = ptr[5];
2151 ptr = getDomainName(msg, ptr+6, end, &rdb->srv.target);
2152 if (ptr != end) { debugf("GetLargeResourceRecord: Malformed SRV RDATA name"); goto fail; }
2153 //debugf("%##s SRV %##s rdlen %d", rr->resrec.name.c, rdb->srv.target.c, pktrdlength);
2154 break;
2155
2156 case kDNSType_OPT: {
2157 rdataOPT *opt = rr->resrec.rdata->u.opt;
2158 rr->resrec.rdlength = 0;
2159 while (ptr < end && (mDNSu8 *)(opt+1) < &rr->resrec.rdata->u.data[MaximumRDSize])
2160 {
2161 const rdataOPT *const currentopt = opt;
2162 if (ptr + 4 > end) { LogInfo("GetLargeResourceRecord: OPT RDATA ptr + 4 > end"); goto fail; }
2163 opt->opt = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]);
2164 opt->optlen = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]);
2165 ptr += 4;
2166 if (ptr + opt->optlen > end) { LogInfo("GetLargeResourceRecord: ptr + opt->optlen > end"); goto fail; }
2167 switch (opt->opt)
2168 {
2169 case kDNSOpt_LLQ:
2170 if (opt->optlen == DNSOpt_LLQData_Space - 4)
2171 {
2172 opt->u.llq.vers = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]);
2173 opt->u.llq.llqOp = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]);
2174 opt->u.llq.err = (mDNSu16)((mDNSu16)ptr[4] << 8 | ptr[5]);
2175 mDNSPlatformMemCopy(opt->u.llq.id.b, ptr+6, 8);
2176 opt->u.llq.llqlease = (mDNSu32) ((mDNSu32)ptr[14] << 24 | (mDNSu32)ptr[15] << 16 | (mDNSu32)ptr[16] << 8 | ptr[17]);
2177 if (opt->u.llq.llqlease > 0x70000000UL / mDNSPlatformOneSecond)
2178 opt->u.llq.llqlease = 0x70000000UL / mDNSPlatformOneSecond;
2179 opt++;
2180 }
2181 break;
2182 case kDNSOpt_Lease:
2183 if (opt->optlen == DNSOpt_LeaseData_Space - 4)
2184 {
2185 opt->u.updatelease = (mDNSu32) ((mDNSu32)ptr[0] << 24 | (mDNSu32)ptr[1] << 16 | (mDNSu32)ptr[2] << 8 | ptr[3]);
2186 if (opt->u.updatelease > 0x70000000UL / mDNSPlatformOneSecond)
2187 opt->u.updatelease = 0x70000000UL / mDNSPlatformOneSecond;
2188 opt++;
2189 }
2190 break;
2191 case kDNSOpt_Owner:
2192 if (ValidOwnerLength(opt->optlen))
2193 {
2194 opt->u.owner.vers = ptr[0];
2195 opt->u.owner.seq = ptr[1];
2196 mDNSPlatformMemCopy(opt->u.owner.HMAC.b, ptr+2, 6); // 6-byte MAC address
2197 mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+2, 6); // 6-byte MAC address
2198 opt->u.owner.password = zeroEthAddr;
2199 if (opt->optlen >= DNSOpt_OwnerData_ID_Wake_Space-4)
2200 {
2201 mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+8, 6); // 6-byte MAC address
2202 // This mDNSPlatformMemCopy is safe because the ValidOwnerLength(opt->optlen) check above
2203 // ensures that opt->optlen is no more than DNSOpt_OwnerData_ID_Wake_PW6_Space - 4
2204 if (opt->optlen > DNSOpt_OwnerData_ID_Wake_Space-4)
2205 mDNSPlatformMemCopy(opt->u.owner.password.b, ptr+14, opt->optlen - (DNSOpt_OwnerData_ID_Wake_Space-4));
2206 }
2207 opt++;
2208 }
2209 break;
2210 }
2211 ptr += currentopt->optlen;
2212 }
2213 rr->resrec.rdlength = (mDNSu16)((mDNSu8*)opt - rr->resrec.rdata->u.data);
2214 if (ptr != end) { LogInfo("GetLargeResourceRecord: Malformed OptRdata"); goto fail; }
2215 break;
2216 }
2217
2218 case kDNSType_NSEC: {
2219 unsigned int i, j;
2220 domainname d;
2221 ptr = getDomainName(msg, ptr, end, &d); // Ignored for our simplified use of NSEC synthetic records
2222 if (!ptr) { LogInfo("GetLargeResourceRecord: Malformed NSEC nextname"); goto fail; }
2223 mDNSPlatformMemZero(rdb->nsec.bitmap, sizeof(rdb->nsec.bitmap));
2224 if (ptr < end)
2225 {
2226 if (*ptr++ != 0) { debugf("GetLargeResourceRecord: We only handle block zero NSECs"); goto fail; }
2227 i = *ptr++;
2228 if (i > sizeof(rdataNSEC)) { debugf("GetLargeResourceRecord: invalid block length %d", i); goto fail; }
2229 for (j=0; j<i; j++) rdb->nsec.bitmap[j] = *ptr++;
2230 }
2231 if (ptr != end) { debugf("GetLargeResourceRecord: Malformed NSEC"); goto fail; }
2232 break;
2233 }
2234
2235 default: if (pktrdlength > rr->resrec.rdata->MaxRDLength)
2236 {
2237 debugf("GetLargeResourceRecord: rdata %d (%s) size (%d) exceeds storage (%d)",
2238 rr->resrec.rrtype, DNSTypeName(rr->resrec.rrtype), pktrdlength, rr->resrec.rdata->MaxRDLength);
2239 goto fail;
2240 }
2241 debugf("GetLargeResourceRecord: Warning! Reading resource type %d (%s) as opaque data",
2242 rr->resrec.rrtype, DNSTypeName(rr->resrec.rrtype));
2243 // Note: Just because we don't understand the record type, that doesn't
2244 // mean we fail. The DNS protocol specifies rdlength, so we can
2245 // safely skip over unknown records and ignore them.
2246 // We also grab a binary copy of the rdata anyway, since the caller
2247 // might know how to interpret it even if we don't.
2248 rr->resrec.rdlength = pktrdlength;
2249 mDNSPlatformMemCopy(rdb->data, ptr, pktrdlength);
2250 break;
2251 }
2252
2253 SetNewRData(&rr->resrec, mDNSNULL, 0); // Sets rdlength, rdestimate, rdatahash for us
2254
2255 // Success! Now fill in RecordType to show this record contains valid data
2256 rr->resrec.RecordType = RecordType;
2257 return(end);
2258
2259 fail:
2260 // If we were unable to parse the rdata in this record, we indicate that by
2261 // returing a 'kDNSRecordTypePacketNegative' record with rdlength set to zero
2262 rr->resrec.RecordType = kDNSRecordTypePacketNegative;
2263 rr->resrec.rdlength = 0;
2264 rr->resrec.rdestimate = 0;
2265 rr->resrec.rdatahash = 0;
2266 return(end);
2267 }
2268
2269 mDNSexport const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end)
2270 {
2271 ptr = skipDomainName(msg, ptr, end);
2272 if (!ptr) { debugf("skipQuestion: Malformed domain name in DNS question section"); return(mDNSNULL); }
2273 if (ptr+4 > end) { debugf("skipQuestion: Malformed DNS question section -- no query type and class!"); return(mDNSNULL); }
2274 return(ptr+4);
2275 }
2276
2277 mDNSexport const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID,
2278 DNSQuestion *question)
2279 {
2280 mDNSPlatformMemZero(question, sizeof(*question));
2281 question->InterfaceID = InterfaceID;
2282 if (!InterfaceID) question->TargetQID = onesID; // In DNSQuestions we use TargetQID as the indicator of whether it's unicast or multicast
2283 ptr = getDomainName(msg, ptr, end, &question->qname);
2284 if (!ptr) { debugf("Malformed domain name in DNS question section"); return(mDNSNULL); }
2285 if (ptr+4 > end) { debugf("Malformed DNS question section -- no query type and class!"); return(mDNSNULL); }
2286
2287 question->qnamehash = DomainNameHashValue(&question->qname);
2288 question->qtype = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); // Get type
2289 question->qclass = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); // and class
2290 return(ptr+4);
2291 }
2292
2293 mDNSexport const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end)
2294 {
2295 int i;
2296 const mDNSu8 *ptr = msg->data;
2297 for (i = 0; i < msg->h.numQuestions && ptr; i++) ptr = skipQuestion(msg, ptr, end);
2298 return(ptr);
2299 }
2300
2301 mDNSexport const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end)
2302 {
2303 int i;
2304 const mDNSu8 *ptr = LocateAnswers(msg, end);
2305 for (i = 0; i < msg->h.numAnswers && ptr; i++) ptr = skipResourceRecord(msg, ptr, end);
2306 return(ptr);
2307 }
2308
2309 mDNSexport const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end)
2310 {
2311 int i;
2312 const mDNSu8 *ptr = LocateAuthorities(msg, end);
2313 for (i = 0; i < msg->h.numAuthorities; i++) ptr = skipResourceRecord(msg, ptr, end);
2314 return (ptr);
2315 }
2316
2317 mDNSexport const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize)
2318 {
2319 int i;
2320 const mDNSu8 *ptr = LocateAdditionals(msg, end);
2321
2322 // Locate the OPT record.
2323 // According to RFC 2671, "One OPT pseudo-RR can be added to the additional data section of either a request or a response."
2324 // This implies that there may be *at most* one OPT record per DNS message, in the Additional Section,
2325 // but not necessarily the *last* entry in the Additional Section.
2326 for (i = 0; ptr && i < msg->h.numAdditionals; i++)
2327 {
2328 if (ptr + DNSOpt_Header_Space + minsize <= end && // Make sure we have 11+minsize bytes of data
2329 ptr[0] == 0 && // Name must be root label
2330 ptr[1] == (kDNSType_OPT >> 8 ) && // rrtype OPT
2331 ptr[2] == (kDNSType_OPT & 0xFF) &&
2332 ((mDNSu16)ptr[9] << 8 | (mDNSu16)ptr[10]) >= (mDNSu16)minsize)
2333 return(ptr);
2334 else
2335 ptr = skipResourceRecord(msg, ptr, end);
2336 }
2337 return(mDNSNULL);
2338 }
2339
2340 // On success, GetLLQOptData returns pointer to storage within shared "m->rec";
2341 // it is caller's responsibilty to clear m->rec.r.resrec.RecordType after use
2342 // Note: An OPT RDataBody actually contains one or more variable-length rdataOPT objects packed together
2343 // The code that currently calls this assumes there's only one, instead of iterating through the set
2344 mDNSexport const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end)
2345 {
2346 const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LLQData_Space);
2347 if (ptr)
2348 {
2349 ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec);
2350 if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative) return(&m->rec.r.resrec.rdata->u.opt[0]);
2351 }
2352 return(mDNSNULL);
2353 }
2354
2355 // Get the lease life of records in a dynamic update
2356 // returns 0 on error or if no lease present
2357 mDNSexport mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end)
2358 {
2359 mDNSu32 result = 0;
2360 const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LeaseData_Space);
2361 if (ptr) ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec);
2362 if (ptr && m->rec.r.resrec.rdlength >= DNSOpt_LeaseData_Space && m->rec.r.resrec.rdata->u.opt[0].opt == kDNSOpt_Lease)
2363 result = m->rec.r.resrec.rdata->u.opt[0].u.updatelease;
2364 m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it
2365 return(result);
2366 }
2367
2368 mDNSlocal const mDNSu8 *DumpRecords(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, int count, char *label)
2369 {
2370 int i;
2371 LogMsg("%2d %s", count, label);
2372 for (i = 0; i < count && ptr; i++)
2373 {
2374 // This puts a LargeCacheRecord on the stack instead of using the shared m->rec storage,
2375 // but since it's only used for debugging (and probably only on OS X, not on
2376 // embedded systems) putting a 9kB object on the stack isn't a big problem.
2377 LargeCacheRecord largecr;
2378 ptr = GetLargeResourceRecord(m, msg, ptr, end, mDNSInterface_Any, kDNSRecordTypePacketAns, &largecr);
2379 if (ptr) LogMsg("%2d TTL%8d %s", i, largecr.r.resrec.rroriginalttl, CRDisplayString(m, &largecr.r));
2380 }
2381 if (!ptr) LogMsg("ERROR: Premature end of packet data");
2382 return(ptr);
2383 }
2384
2385 #define DNS_OP_Name(X) ( \
2386 (X) == kDNSFlag0_OP_StdQuery ? "" : \
2387 (X) == kDNSFlag0_OP_Iquery ? "Iquery " : \
2388 (X) == kDNSFlag0_OP_Status ? "Status " : \
2389 (X) == kDNSFlag0_OP_Unused3 ? "Unused3 " : \
2390 (X) == kDNSFlag0_OP_Notify ? "Notify " : \
2391 (X) == kDNSFlag0_OP_Update ? "Update " : "?? " )
2392
2393 #define DNS_RC_Name(X) ( \
2394 (X) == kDNSFlag1_RC_NoErr ? "NoErr" : \
2395 (X) == kDNSFlag1_RC_FormErr ? "FormErr" : \
2396 (X) == kDNSFlag1_RC_ServFail ? "ServFail" : \
2397 (X) == kDNSFlag1_RC_NXDomain ? "NXDomain" : \
2398 (X) == kDNSFlag1_RC_NotImpl ? "NotImpl" : \
2399 (X) == kDNSFlag1_RC_Refused ? "Refused" : \
2400 (X) == kDNSFlag1_RC_YXDomain ? "YXDomain" : \
2401 (X) == kDNSFlag1_RC_YXRRSet ? "YXRRSet" : \
2402 (X) == kDNSFlag1_RC_NXRRSet ? "NXRRSet" : \
2403 (X) == kDNSFlag1_RC_NotAuth ? "NotAuth" : \
2404 (X) == kDNSFlag1_RC_NotZone ? "NotZone" : "??" )
2405
2406 // Note: DumpPacket expects the packet header fields in host byte order, not network byte order
2407 mDNSexport void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport,
2408 const mDNSAddr *srcaddr, mDNSIPPort srcport,
2409 const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end)
2410 {
2411 mDNSBool IsUpdate = ((msg->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update);
2412 const mDNSu8 *ptr = msg->data;
2413 int i;
2414 DNSQuestion q;
2415 char tbuffer[64], sbuffer[64], dbuffer[64] = "";
2416 if (!status) tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), sent ? "Sent" : "Received" )] = 0;
2417 else tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), "ERROR %d %sing", status, sent ? "Send" : "Receiv")] = 0;
2418 if (sent) sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "port " )] = 0;
2419 else sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "%#a:", srcaddr)] = 0;
2420 if (dstaddr || !mDNSIPPortIsZero(dstport))
2421 dbuffer[mDNS_snprintf(dbuffer, sizeof(dbuffer), " to %#a:%d", dstaddr, mDNSVal16(dstport))] = 0;
2422
2423 LogMsg("-- %s %s DNS %s%s (flags %02X%02X) RCODE: %s (%d) %s%s%s%s%s%sID: %d %d bytes from %s%d%s%s --",
2424 tbuffer, transport,
2425 DNS_OP_Name(msg->h.flags.b[0] & kDNSFlag0_OP_Mask),
2426 msg->h.flags.b[0] & kDNSFlag0_QR_Response ? "Response" : "Query",
2427 msg->h.flags.b[0], msg->h.flags.b[1],
2428 DNS_RC_Name(msg->h.flags.b[1] & kDNSFlag1_RC_Mask),
2429 msg->h.flags.b[1] & kDNSFlag1_RC_Mask,
2430 msg->h.flags.b[0] & kDNSFlag0_AA ? "AA " : "",
2431 msg->h.flags.b[0] & kDNSFlag0_TC ? "TC " : "",
2432 msg->h.flags.b[0] & kDNSFlag0_RD ? "RD " : "",
2433 msg->h.flags.b[1] & kDNSFlag1_RA ? "RA " : "",
2434 msg->h.flags.b[1] & kDNSFlag1_AD ? "AD " : "",
2435 msg->h.flags.b[1] & kDNSFlag1_CD ? "CD " : "",
2436 mDNSVal16(msg->h.id),
2437 end - msg->data,
2438 sbuffer, mDNSVal16(srcport), dbuffer,
2439 (msg->h.flags.b[0] & kDNSFlag0_TC) ? " (truncated)" : ""
2440 );
2441
2442 LogMsg("%2d %s", msg->h.numQuestions, IsUpdate ? "Zone" : "Questions");
2443 for (i = 0; i < msg->h.numQuestions && ptr; i++)
2444 {
2445 ptr = getQuestion(msg, ptr, end, mDNSInterface_Any, &q);
2446 if (ptr) LogMsg("%2d %##s %s", i, q.qname.c, DNSTypeName(q.qtype));
2447 }
2448 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAnswers, IsUpdate ? "Prerequisites" : "Answers");
2449 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAuthorities, IsUpdate ? "Updates" : "Authorities");
2450 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAdditionals, "Additionals");
2451 LogMsg("--------------");
2452 }
2453
2454 // ***************************************************************************
2455 #if COMPILER_LIKES_PRAGMA_MARK
2456 #pragma mark -
2457 #pragma mark - Packet Sending Functions
2458 #endif
2459
2460 // Stub definition of TCPSocket_struct so we can access flags field. (Rest of TCPSocket_struct is platform-dependent.)
2461 struct TCPSocket_struct { TCPSocketFlags flags; /* ... */ };
2462
2463 struct UDPSocket_struct
2464 {
2465 mDNSIPPort port; // MUST BE FIRST FIELD -- mDNSCoreReceive expects every UDPSocket_struct to begin with mDNSIPPort port
2466 };
2467
2468 // Note: When we sign a DNS message using DNSDigest_SignMessage(), the current real-time clock value is used, which
2469 // is why we generally defer signing until we send the message, to ensure the signature is as fresh as possible.
2470 mDNSexport mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end,
2471 mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo)
2472 {
2473 mStatus status = mStatus_NoError;
2474 const mDNSu16 numAdditionals = msg->h.numAdditionals;
2475 mDNSu8 *newend;
2476 mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData;
2477
2478 // Zero-length message data is okay (e.g. for a DNS Update ack, where all we need is an ID and an error code
2479 if (end < msg->data || end - msg->data > AbsoluteMaxDNSMessageData)
2480 {
2481 LogMsg("mDNSSendDNSMessage: invalid message %p %p %d", msg->data, end, end - msg->data);
2482 return mStatus_BadParamErr;
2483 }
2484
2485 newend = putHINFO(m, msg, end, authInfo, limit);
2486 if (!newend) LogMsg("mDNSSendDNSMessage: putHINFO failed msg %p end %p, limit %p", msg->data, end, limit); // Not fatal
2487 else end = newend;
2488
2489 // Put all the integer values in IETF byte-order (MSB first, LSB second)
2490 SwapDNSHeaderBytes(msg);
2491
2492 if (authInfo) DNSDigest_SignMessage(msg, &end, authInfo, 0); // DNSDigest_SignMessage operates on message in network byte order
2493 if (!end) { LogMsg("mDNSSendDNSMessage: DNSDigest_SignMessage failed"); status = mStatus_NoMemoryErr; }
2494 else
2495 {
2496 // Send the packet on the wire
2497 if (!sock)
2498 status = mDNSPlatformSendUDP(m, msg, end, InterfaceID, src, dst, dstport);
2499 else
2500 {
2501 mDNSu16 msglen = (mDNSu16)(end - (mDNSu8 *)msg);
2502 mDNSu8 lenbuf[2] = { (mDNSu8)(msglen >> 8), (mDNSu8)(msglen & 0xFF) };
2503 long nsent = mDNSPlatformWriteTCP(sock, (char*)lenbuf, 2); // Should do scatter/gather here -- this is probably going out as two packets
2504 if (nsent != 2) { LogMsg("mDNSSendDNSMessage: write msg length failed %d/%d", nsent, 2); status = mStatus_ConnFailed; }
2505 else
2506 {
2507 nsent = mDNSPlatformWriteTCP(sock, (char *)msg, msglen);
2508 if (nsent != msglen) { LogMsg("mDNSSendDNSMessage: write msg body failed %d/%d", nsent, msglen); status = mStatus_ConnFailed; }
2509 }
2510 }
2511 }
2512
2513 // Swap the integer values back the way they were (remember that numAdditionals may have been changed by putHINFO and/or SignMessage)
2514 SwapDNSHeaderBytes(msg);
2515
2516 // Dump the packet with the HINFO and TSIG
2517 if (mDNS_PacketLoggingEnabled && !mDNSOpaque16IsZero(msg->h.id))
2518 DumpPacket(m, status, mDNStrue, sock && (sock->flags & kTCPSocketFlags_UseTLS) ? "TLS" : sock ? "TCP" : "UDP", mDNSNULL, src ? src->port : MulticastDNSPort, dst, dstport, msg, end);
2519
2520 // put the number of additionals back the way it was
2521 msg->h.numAdditionals = numAdditionals;
2522
2523 return(status);
2524 }
2525
2526 // ***************************************************************************
2527 #if COMPILER_LIKES_PRAGMA_MARK
2528 #pragma mark -
2529 #pragma mark - RR List Management & Task Management
2530 #endif
2531
2532 mDNSexport void mDNS_Lock_(mDNS *const m, const char * const functionname)
2533 {
2534 // MUST grab the platform lock FIRST!
2535 mDNSPlatformLock(m);
2536
2537 // Normally, mDNS_reentrancy is zero and so is mDNS_busy
2538 // However, when we call a client callback mDNS_busy is one, and we increment mDNS_reentrancy too
2539 // If that client callback does mDNS API calls, mDNS_reentrancy and mDNS_busy will both be one
2540 // If mDNS_busy != mDNS_reentrancy that's a bad sign
2541 if (m->mDNS_busy != m->mDNS_reentrancy)
2542 {
2543 LogMsg("%s: mDNS_Lock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy);
2544 #if ForceAlerts
2545 *(long*)0 = 0;
2546 #endif
2547 }
2548
2549 // If this is an initial entry into the mDNSCore code, set m->timenow
2550 // else, if this is a re-entrant entry into the mDNSCore code, m->timenow should already be set
2551 if (m->mDNS_busy == 0)
2552 {
2553 if (m->timenow)
2554 LogMsg("%s: mDNS_Lock: m->timenow already set (%ld/%ld)", functionname, m->timenow, mDNS_TimeNow_NoLock(m));
2555 m->timenow = mDNS_TimeNow_NoLock(m);
2556 if (m->timenow == 0) m->timenow = 1;
2557 }
2558 else if (m->timenow == 0)
2559 {
2560 LogMsg("%s: mDNS_Lock: m->mDNS_busy is %ld but m->timenow not set", functionname, m->mDNS_busy);
2561 m->timenow = mDNS_TimeNow_NoLock(m);
2562 if (m->timenow == 0) m->timenow = 1;
2563 }
2564
2565 if (m->timenow_last - m->timenow > 0)
2566 {
2567 m->timenow_adjust += m->timenow_last - m->timenow;
2568 LogMsg("%s: mDNSPlatformRawTime went backwards by %ld ticks; setting correction factor to %ld", functionname, m->timenow_last - m->timenow, m->timenow_adjust);
2569 m->timenow = m->timenow_last;
2570 }
2571 m->timenow_last = m->timenow;
2572
2573 // Increment mDNS_busy so we'll recognise re-entrant calls
2574 m->mDNS_busy++;
2575 }
2576
2577 mDNSlocal AuthRecord *AnyLocalRecordReady(const mDNS *const m)
2578 {
2579 AuthRecord *rr;
2580 for (rr = m->NewLocalRecords; rr; rr = rr->next)
2581 if (LocalRecordReady(rr)) return rr;
2582 return mDNSNULL;
2583 }
2584
2585 mDNSlocal mDNSs32 GetNextScheduledEvent(const mDNS *const m)
2586 {
2587 mDNSs32 e = m->timenow + 0x78000000;
2588 if (m->mDNSPlatformStatus != mStatus_NoError) return(e);
2589 if (m->NewQuestions)
2590 {
2591 if (m->NewQuestions->DelayAnswering) e = m->NewQuestions->DelayAnswering;
2592 else return(m->timenow);
2593 }
2594 if (m->NewLocalOnlyQuestions) return(m->timenow);
2595 if (m->NewLocalRecords && AnyLocalRecordReady(m)) return(m->timenow);
2596 if (m->SPSProxyListChanged) return(m->timenow);
2597 if (m->LocalRemoveEvents) return(m->timenow);
2598
2599 #ifndef UNICAST_DISABLED
2600 if (e - m->NextuDNSEvent > 0) e = m->NextuDNSEvent;
2601 if (e - m->NextScheduledNATOp > 0) e = m->NextScheduledNATOp;
2602 if (m->NextSRVUpdate && e - m->NextSRVUpdate > 0) e = m->NextSRVUpdate;
2603 #endif
2604
2605 if (e - m->NextCacheCheck > 0) e = m->NextCacheCheck;
2606 if (e - m->NextScheduledSPS > 0) e = m->NextScheduledSPS;
2607 // NextScheduledSPRetry only valid when DelaySleep not set
2608 if (!m->DelaySleep && m->SleepLimit && e - m->NextScheduledSPRetry > 0) e = m->NextScheduledSPRetry;
2609 if (m->DelaySleep && e - m->DelaySleep > 0) e = m->DelaySleep;
2610
2611 if (m->SuppressSending)
2612 {
2613 if (e - m->SuppressSending > 0) e = m->SuppressSending;
2614 }
2615 else
2616 {
2617 if (e - m->NextScheduledQuery > 0) e = m->NextScheduledQuery;
2618 if (e - m->NextScheduledProbe > 0) e = m->NextScheduledProbe;
2619 if (e - m->NextScheduledResponse > 0) e = m->NextScheduledResponse;
2620 }
2621
2622 return(e);
2623 }
2624
2625 mDNSexport void ShowTaskSchedulingError(mDNS *const m)
2626 {
2627 mDNS_Lock(m);
2628
2629 LogMsg("Task Scheduling Error: Continuously busy for more than a second");
2630
2631 // Note: To accurately diagnose *why* we're busy, the debugging code here needs to mirror the logic in GetNextScheduledEvent above
2632
2633 if (m->NewQuestions && (!m->NewQuestions->DelayAnswering || m->timenow - m->NewQuestions->DelayAnswering >= 0))
2634 LogMsg("Task Scheduling Error: NewQuestion %##s (%s)",
2635 m->NewQuestions->qname.c, DNSTypeName(m->NewQuestions->qtype));
2636
2637 if (m->NewLocalOnlyQuestions)
2638 LogMsg("Task Scheduling Error: NewLocalOnlyQuestions %##s (%s)",
2639 m->NewLocalOnlyQuestions->qname.c, DNSTypeName(m->NewLocalOnlyQuestions->qtype));
2640
2641 if (m->NewLocalRecords)
2642 {
2643 AuthRecord *rr = AnyLocalRecordReady(m);
2644 if (rr) LogMsg("Task Scheduling Error: NewLocalRecords %s", ARDisplayString(m, rr));
2645 }
2646
2647 if (m->SPSProxyListChanged) LogMsg("Task Scheduling Error: SPSProxyListChanged");
2648 if (m->LocalRemoveEvents) LogMsg("Task Scheduling Error: LocalRemoveEvents");
2649
2650 if (m->timenow - m->NextScheduledEvent >= 0)
2651 LogMsg("Task Scheduling Error: m->NextScheduledEvent %d", m->timenow - m->NextScheduledEvent);
2652
2653 #ifndef UNICAST_DISABLED
2654 if (m->timenow - m->NextuDNSEvent >= 0)
2655 LogMsg("Task Scheduling Error: m->NextuDNSEvent %d", m->timenow - m->NextuDNSEvent);
2656 if (m->timenow - m->NextScheduledNATOp >= 0)
2657 LogMsg("Task Scheduling Error: m->NextScheduledNATOp %d", m->timenow - m->NextScheduledNATOp);
2658 if (m->NextSRVUpdate && m->timenow - m->NextSRVUpdate >= 0)
2659 LogMsg("Task Scheduling Error: m->NextSRVUpdate %d", m->timenow - m->NextSRVUpdate);
2660 #endif
2661
2662 if (m->timenow - m->NextCacheCheck >= 0)
2663 LogMsg("Task Scheduling Error: m->NextCacheCheck %d", m->timenow - m->NextCacheCheck);
2664 if (m->timenow - m->NextScheduledSPS >= 0)
2665 LogMsg("Task Scheduling Error: m->NextScheduledSPS %d", m->timenow - m->NextScheduledSPS);
2666 if (!m->DelaySleep && m->SleepLimit && m->timenow - m->NextScheduledSPRetry >= 0)
2667 LogMsg("Task Scheduling Error: m->NextScheduledSPRetry %d", m->timenow - m->NextScheduledSPRetry);
2668 if (m->DelaySleep && m->timenow - m->DelaySleep >= 0)
2669 LogMsg("Task Scheduling Error: m->DelaySleep %d", m->timenow - m->DelaySleep);
2670
2671 if (m->SuppressSending && m->timenow - m->SuppressSending >= 0)
2672 LogMsg("Task Scheduling Error: m->SuppressSending %d", m->timenow - m->SuppressSending);
2673 if (m->timenow - m->NextScheduledQuery >= 0)
2674 LogMsg("Task Scheduling Error: m->NextScheduledQuery %d", m->timenow - m->NextScheduledQuery);
2675 if (m->timenow - m->NextScheduledProbe >= 0)
2676 LogMsg("Task Scheduling Error: m->NextScheduledProbe %d", m->timenow - m->NextScheduledProbe);
2677 if (m->timenow - m->NextScheduledResponse >= 0)
2678 LogMsg("Task Scheduling Error: m->NextScheduledResponse %d", m->timenow - m->NextScheduledResponse);
2679
2680 mDNS_Unlock(m);
2681 }
2682
2683 mDNSexport void mDNS_Unlock_(mDNS *const m, const char * const functionname)
2684 {
2685 // Decrement mDNS_busy
2686 m->mDNS_busy--;
2687
2688 // Check for locking failures
2689 if (m->mDNS_busy != m->mDNS_reentrancy)
2690 {
2691 LogMsg("%s: mDNS_Unlock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy);
2692 #if ForceAlerts
2693 *(long*)0 = 0;
2694 #endif
2695 }
2696
2697 // If this is a final exit from the mDNSCore code, set m->NextScheduledEvent and clear m->timenow
2698 if (m->mDNS_busy == 0)
2699 {
2700 m->NextScheduledEvent = GetNextScheduledEvent(m);
2701 if (m->timenow == 0) LogMsg("%s: mDNS_Unlock: ERROR! m->timenow aready zero", functionname);
2702 m->timenow = 0;
2703 }
2704
2705 // MUST release the platform lock LAST!
2706 mDNSPlatformUnlock(m);
2707 }
2708
2709 // ***************************************************************************
2710 #if COMPILER_LIKES_PRAGMA_MARK
2711 #pragma mark -
2712 #pragma mark - Specialized mDNS version of vsnprintf
2713 #endif
2714
2715 static const struct mDNSprintf_format
2716 {
2717 unsigned leftJustify : 1;
2718 unsigned forceSign : 1;
2719 unsigned zeroPad : 1;
2720 unsigned havePrecision : 1;
2721 unsigned hSize : 1;
2722 unsigned lSize : 1;
2723 char altForm;
2724 char sign; // +, - or space
2725 unsigned int fieldWidth;
2726 unsigned int precision;
2727 } mDNSprintf_format_default = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
2728
2729 mDNSexport mDNSu32 mDNS_vsnprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, va_list arg)
2730 {
2731 mDNSu32 nwritten = 0;
2732 int c;
2733 if (buflen == 0) return(0);
2734 buflen--; // Pre-reserve one space in the buffer for the terminating null
2735 if (buflen == 0) goto exit;
2736
2737 for (c = *fmt; c != 0; c = *++fmt)
2738 {
2739 if (c != '%')
2740 {
2741 *sbuffer++ = (char)c;
2742 if (++nwritten >= buflen) goto exit;
2743 }
2744 else
2745 {
2746 unsigned int i=0, j;
2747 // The mDNS Vsprintf Argument Conversion Buffer is used as a temporary holding area for
2748 // generating decimal numbers, hexdecimal numbers, IP addresses, domain name strings, etc.
2749 // The size needs to be enough for a 256-byte domain name plus some error text.
2750 #define mDNS_VACB_Size 300
2751 char mDNS_VACB[mDNS_VACB_Size];
2752 #define mDNS_VACB_Lim (&mDNS_VACB[mDNS_VACB_Size])
2753 #define mDNS_VACB_Remain(s) ((mDNSu32)(mDNS_VACB_Lim - s))
2754 char *s = mDNS_VACB_Lim, *digits;
2755 struct mDNSprintf_format F = mDNSprintf_format_default;
2756
2757 while (1) // decode flags
2758 {
2759 c = *++fmt;
2760 if (c == '-') F.leftJustify = 1;
2761 else if (c == '+') F.forceSign = 1;
2762 else if (c == ' ') F.sign = ' ';
2763 else if (c == '#') F.altForm++;
2764 else if (c == '0') F.zeroPad = 1;
2765 else break;
2766 }
2767
2768 if (c == '*') // decode field width
2769 {
2770 int f = va_arg(arg, int);
2771 if (f < 0) { f = -f; F.leftJustify = 1; }
2772 F.fieldWidth = (unsigned int)f;
2773 c = *++fmt;
2774 }
2775 else
2776 {
2777 for (; c >= '0' && c <= '9'; c = *++fmt)
2778 F.fieldWidth = (10 * F.fieldWidth) + (c - '0');
2779 }
2780
2781 if (c == '.') // decode precision
2782 {
2783 if ((c = *++fmt) == '*')
2784 { F.precision = va_arg(arg, unsigned int); c = *++fmt; }
2785 else for (; c >= '0' && c <= '9'; c = *++fmt)
2786 F.precision = (10 * F.precision) + (c - '0');
2787 F.havePrecision = 1;
2788 }
2789
2790 if (F.leftJustify) F.zeroPad = 0;
2791
2792 conv:
2793 switch (c) // perform appropriate conversion
2794 {
2795 unsigned long n;
2796 case 'h' : F.hSize = 1; c = *++fmt; goto conv;
2797 case 'l' : // fall through
2798 case 'L' : F.lSize = 1; c = *++fmt; goto conv;
2799 case 'd' :
2800 case 'i' : if (F.lSize) n = (unsigned long)va_arg(arg, long);
2801 else n = (unsigned long)va_arg(arg, int);
2802 if (F.hSize) n = (short) n;
2803 if ((long) n < 0) { n = (unsigned long)-(long)n; F.sign = '-'; }
2804 else if (F.forceSign) F.sign = '+';
2805 goto decimal;
2806 case 'u' : if (F.lSize) n = va_arg(arg, unsigned long);
2807 else n = va_arg(arg, unsigned int);
2808 if (F.hSize) n = (unsigned short) n;
2809 F.sign = 0;
2810 goto decimal;
2811 decimal: if (!F.havePrecision)
2812 {
2813 if (F.zeroPad)
2814 {
2815 F.precision = F.fieldWidth;
2816 if (F.sign) --F.precision;
2817 }
2818 if (F.precision < 1) F.precision = 1;
2819 }
2820 if (F.precision > mDNS_VACB_Size - 1)
2821 F.precision = mDNS_VACB_Size - 1;
2822 for (i = 0; n; n /= 10, i++) *--s = (char)(n % 10 + '0');
2823 for (; i < F.precision; i++) *--s = '0';
2824 if (F.sign) { *--s = F.sign; i++; }
2825 break;
2826
2827 case 'o' : if (F.lSize) n = va_arg(arg, unsigned long);
2828 else n = va_arg(arg, unsigned int);
2829 if (F.hSize) n = (unsigned short) n;
2830 if (!F.havePrecision)
2831 {
2832 if (F.zeroPad) F.precision = F.fieldWidth;
2833 if (F.precision < 1) F.precision = 1;
2834 }
2835 if (F.precision > mDNS_VACB_Size - 1)
2836 F.precision = mDNS_VACB_Size - 1;
2837 for (i = 0; n; n /= 8, i++) *--s = (char)(n % 8 + '0');
2838 if (F.altForm && i && *s != '0') { *--s = '0'; i++; }
2839 for (; i < F.precision; i++) *--s = '0';
2840 break;
2841
2842 case 'a' : {
2843 unsigned char *a = va_arg(arg, unsigned char *);
2844 if (!a) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; }
2845 else
2846 {
2847 s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end
2848 if (F.altForm)
2849 {
2850 mDNSAddr *ip = (mDNSAddr*)a;
2851 switch (ip->type)
2852 {
2853 case mDNSAddrType_IPv4: F.precision = 4; a = (unsigned char *)&ip->ip.v4; break;
2854 case mDNSAddrType_IPv6: F.precision = 16; a = (unsigned char *)&ip->ip.v6; break;
2855 default: F.precision = 0; break;
2856 }
2857 }
2858 if (F.altForm && !F.precision)
2859 i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "«ZERO ADDRESS»");
2860 else switch (F.precision)
2861 {
2862 case 4: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%d.%d.%d.%d",
2863 a[0], a[1], a[2], a[3]); break;
2864 case 6: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%02X:%02X:%02X:%02X:%02X:%02X",
2865 a[0], a[1], a[2], a[3], a[4], a[5]); break;
2866 case 16: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB),
2867 "%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X",
2868 a[0x0], a[0x1], a[0x2], a[0x3], a[0x4], a[0x5], a[0x6], a[0x7],
2869 a[0x8], a[0x9], a[0xA], a[0xB], a[0xC], a[0xD], a[0xE], a[0xF]); break;
2870 default: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%s", "<< ERROR: Must specify"
2871 " address size (i.e. %.4a=IPv4, %.6a=Ethernet, %.16a=IPv6) >>"); break;
2872 }
2873 }
2874 }
2875 break;
2876
2877 case 'p' : F.havePrecision = F.lSize = 1;
2878 F.precision = sizeof(void*) * 2; // 8 characters on 32-bit; 16 characters on 64-bit
2879 case 'X' : digits = "0123456789ABCDEF";
2880 goto hexadecimal;
2881 case 'x' : digits = "0123456789abcdef";
2882 hexadecimal:if (F.lSize) n = va_arg(arg, unsigned long);
2883 else n = va_arg(arg, unsigned int);
2884 if (F.hSize) n = (unsigned short) n;
2885 if (!F.havePrecision)
2886 {
2887 if (F.zeroPad)
2888 {
2889 F.precision = F.fieldWidth;
2890 if (F.altForm) F.precision -= 2;
2891 }
2892 if (F.precision < 1) F.precision = 1;
2893 }
2894 if (F.precision > mDNS_VACB_Size - 1)
2895 F.precision = mDNS_VACB_Size - 1;
2896 for (i = 0; n; n /= 16, i++) *--s = digits[n % 16];
2897 for (; i < F.precision; i++) *--s = '0';
2898 if (F.altForm) { *--s = (char)c; *--s = '0'; i += 2; }
2899 break;
2900
2901 case 'c' : *--s = (char)va_arg(arg, int); i = 1; break;
2902
2903 case 's' : s = va_arg(arg, char *);
2904 if (!s) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; }
2905 else switch (F.altForm)
2906 {
2907 case 0: i=0;
2908 if (!F.havePrecision) // C string
2909 while (s[i]) i++;
2910 else
2911 {
2912 while ((i < F.precision) && s[i]) i++;
2913 // Make sure we don't truncate in the middle of a UTF-8 character
2914 // If last character we got was any kind of UTF-8 multi-byte character,
2915 // then see if we have to back up.
2916 // This is not as easy as the similar checks below, because
2917 // here we can't assume it's safe to examine the *next* byte, so we
2918 // have to confine ourselves to working only backwards in the string.
2919 j = i; // Record where we got to
2920 // Now, back up until we find first non-continuation-char
2921 while (i>0 && (s[i-1] & 0xC0) == 0x80) i--;
2922 // Now s[i-1] is the first non-continuation-char
2923 // and (j-i) is the number of continuation-chars we found
2924 if (i>0 && (s[i-1] & 0xC0) == 0xC0) // If we found a start-char
2925 {
2926 i--; // Tentatively eliminate this start-char as well
2927 // Now (j-i) is the number of characters we're considering eliminating.
2928 // To be legal UTF-8, the start-char must contain (j-i) one-bits,
2929 // followed by a zero bit. If we shift it right by (7-(j-i)) bits
2930 // (with sign extension) then the result has to be 0xFE.
2931 // If this is right, then we reinstate the tentatively eliminated bytes.
2932 if (((j-i) < 7) && (((s[i] >> (7-(j-i))) & 0xFF) == 0xFE)) i = j;
2933 }
2934 }
2935 break;
2936 case 1: i = (unsigned char) *s++; break; // Pascal string
2937 case 2: { // DNS label-sequence name
2938 unsigned char *a = (unsigned char *)s;
2939 s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end
2940 if (*a == 0) *s++ = '.'; // Special case for root DNS name
2941 while (*a)
2942 {
2943 char buf[63*4+1];
2944 if (*a > 63)
2945 { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<INVALID LABEL LENGTH %u>>", *a); break; }
2946 if (s + *a >= &mDNS_VACB[254])
2947 { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<NAME TOO LONG>>"); break; }
2948 // Need to use ConvertDomainLabelToCString to do proper escaping here,
2949 // so it's clear what's a literal dot and what's a label separator
2950 ConvertDomainLabelToCString((domainlabel*)a, buf);
2951 s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "%s.", buf);
2952 a += 1 + *a;
2953 }
2954 i = (mDNSu32)(s - mDNS_VACB);
2955 s = mDNS_VACB; // Reset s back to the start of the buffer
2956 break;
2957 }
2958 }
2959 // Make sure we don't truncate in the middle of a UTF-8 character (see similar comment below)
2960 if (F.havePrecision && i > F.precision)
2961 { i = F.precision; while (i>0 && (s[i] & 0xC0) == 0x80) i--; }
2962 break;
2963
2964 case 'n' : s = va_arg(arg, char *);
2965 if (F.hSize) * (short *) s = (short)nwritten;
2966 else if (F.lSize) * (long *) s = (long)nwritten;
2967 else * (int *) s = (int)nwritten;
2968 continue;
2969
2970 default: s = mDNS_VACB;
2971 i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "<<UNKNOWN FORMAT CONVERSION CODE %%%c>>", c);
2972
2973 case '%' : *sbuffer++ = (char)c;
2974 if (++nwritten >= buflen) goto exit;
2975 break;
2976 }
2977
2978 if (i < F.fieldWidth && !F.leftJustify) // Pad on the left
2979 do {
2980 *sbuffer++ = ' ';
2981 if (++nwritten >= buflen) goto exit;
2982 } while (i < --F.fieldWidth);
2983
2984 // Make sure we don't truncate in the middle of a UTF-8 character.
2985 // Note: s[i] is the first eliminated character; i.e. the next character *after* the last character of the
2986 // allowed output. If s[i] is a UTF-8 continuation character, then we've cut a unicode character in half,
2987 // so back up 'i' until s[i] is no longer a UTF-8 continuation character. (if the input was proprly
2988 // formed, s[i] will now be the UTF-8 start character of the multi-byte character we just eliminated).
2989 if (i > buflen - nwritten)
2990 { i = buflen - nwritten; while (i>0 && (s[i] & 0xC0) == 0x80) i--; }
2991 for (j=0; j<i; j++) *sbuffer++ = *s++; // Write the converted result
2992 nwritten += i;
2993 if (nwritten >= buflen) goto exit;
2994
2995 for (; i < F.fieldWidth; i++) // Pad on the right
2996 {
2997 *sbuffer++ = ' ';
2998 if (++nwritten >= buflen) goto exit;
2999 }
3000 }
3001 }
3002 exit:
3003 *sbuffer++ = 0;
3004 return(nwritten);
3005 }
3006
3007 mDNSexport mDNSu32 mDNS_snprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, ...)
3008 {
3009 mDNSu32 length;
3010
3011 va_list ptr;
3012 va_start(ptr,fmt);
3013 length = mDNS_vsnprintf(sbuffer, buflen, fmt, ptr);
3014 va_end(ptr);
3015
3016 return(length);
3017 }
mirror of mDNSResponder