diff options
Diffstat (limited to 'mDNSResponder/mDNSCore/DNSCommon.c')
| -rw-r--r-- | mDNSResponder/mDNSCore/DNSCommon.c | 4319 |
1 files changed, 4319 insertions, 0 deletions
diff --git a/mDNSResponder/mDNSCore/DNSCommon.c b/mDNSResponder/mDNSCore/DNSCommon.c new file mode 100644 index 00000000..947607cf --- /dev/null +++ b/mDNSResponder/mDNSCore/DNSCommon.c @@ -0,0 +1,4319 @@ +/* -*- Mode: C; tab-width: 4 -*- + * + * Copyright (c) 2002-2013 Apple Computer, Inc. All rights reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +// Set mDNS_InstantiateInlines to tell mDNSEmbeddedAPI.h to instantiate inline functions, if necessary +#define mDNS_InstantiateInlines 1 +#include "DNSCommon.h" +#include "CryptoAlg.h" +#include "anonymous.h" + +// Disable certain benign warnings with Microsoft compilers +#if (defined(_MSC_VER)) +// Disable "conditional expression is constant" warning for debug macros. +// Otherwise, this generates warnings for the perfectly natural construct "while(1)" +// If someone knows a variant way of writing "while(1)" that doesn't generate warning messages, please let us know + #pragma warning(disable:4127) +// Disable "array is too small to include a terminating null character" warning +// -- domain labels have an initial length byte, not a terminating null character + #pragma warning(disable:4295) +#endif + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - Program Constants +#endif + +mDNSexport const mDNSInterfaceID mDNSInterface_Any = 0; +mDNSexport const mDNSInterfaceID mDNSInterfaceMark = (mDNSInterfaceID)-1; +mDNSexport const mDNSInterfaceID mDNSInterface_LocalOnly = (mDNSInterfaceID)-2; +mDNSexport const mDNSInterfaceID mDNSInterface_Unicast = (mDNSInterfaceID)-3; +mDNSexport const mDNSInterfaceID mDNSInterface_P2P = (mDNSInterfaceID)-4; +mDNSexport const mDNSInterfaceID uDNSInterfaceMark = (mDNSInterfaceID)-5; + +// Note: Microsoft's proposed "Link Local Multicast Name Resolution Protocol" (LLMNR) is essentially a limited version of +// Multicast DNS, using the same packet formats, naming syntax, and record types as Multicast DNS, but on a different UDP +// port and multicast address, which means it won't interoperate with the existing installed base of Multicast DNS responders. +// LLMNR uses IPv4 multicast address 224.0.0.252, IPv6 multicast address FF02::0001:0003, and UDP port 5355. +// Uncomment the appropriate lines below to build a special Multicast DNS responder for testing interoperability +// with Microsoft's LLMNR client code. + +#define DiscardPortAsNumber 9 +#define SSHPortAsNumber 22 +#define UnicastDNSPortAsNumber 53 +#define SSDPPortAsNumber 1900 +#define IPSECPortAsNumber 4500 +#define NSIPCPortAsNumber 5030 // Port used for dnsextd to talk to local nameserver bound to loopback +#define NATPMPAnnouncementPortAsNumber 5350 +#define NATPMPPortAsNumber 5351 +#define DNSEXTPortAsNumber 5352 // Port used for end-to-end DNS operations like LLQ, Updates with Leases, etc. +#define MulticastDNSPortAsNumber 5353 +#define LoopbackIPCPortAsNumber 5354 +//#define MulticastDNSPortAsNumber 5355 // LLMNR +#define PrivateDNSPortAsNumber 5533 + +mDNSexport const mDNSIPPort DiscardPort = { { DiscardPortAsNumber >> 8, DiscardPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort SSHPort = { { SSHPortAsNumber >> 8, SSHPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort UnicastDNSPort = { { UnicastDNSPortAsNumber >> 8, UnicastDNSPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort SSDPPort = { { SSDPPortAsNumber >> 8, SSDPPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort IPSECPort = { { IPSECPortAsNumber >> 8, IPSECPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort NSIPCPort = { { NSIPCPortAsNumber >> 8, NSIPCPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort NATPMPAnnouncementPort = { { NATPMPAnnouncementPortAsNumber >> 8, NATPMPAnnouncementPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort NATPMPPort = { { NATPMPPortAsNumber >> 8, NATPMPPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort DNSEXTPort = { { DNSEXTPortAsNumber >> 8, DNSEXTPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort MulticastDNSPort = { { MulticastDNSPortAsNumber >> 8, MulticastDNSPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort LoopbackIPCPort = { { LoopbackIPCPortAsNumber >> 8, LoopbackIPCPortAsNumber & 0xFF } }; +mDNSexport const mDNSIPPort PrivateDNSPort = { { PrivateDNSPortAsNumber >> 8, PrivateDNSPortAsNumber & 0xFF } }; + +mDNSexport const OwnerOptData zeroOwner = { 0, 0, { { 0 } }, { { 0 } }, { { 0 } } }; + +mDNSexport const mDNSIPPort zeroIPPort = { { 0 } }; +mDNSexport const mDNSv4Addr zerov4Addr = { { 0 } }; +mDNSexport const mDNSv6Addr zerov6Addr = { { 0 } }; +mDNSexport const mDNSEthAddr zeroEthAddr = { { 0 } }; +mDNSexport const mDNSv4Addr onesIPv4Addr = { { 255, 255, 255, 255 } }; +mDNSexport const mDNSv6Addr onesIPv6Addr = { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 } }; +mDNSexport const mDNSEthAddr onesEthAddr = { { 255, 255, 255, 255, 255, 255 } }; +mDNSexport const mDNSAddr zeroAddr = { mDNSAddrType_None, {{{ 0 }}} }; + +mDNSexport const mDNSv4Addr AllDNSAdminGroup = { { 239, 255, 255, 251 } }; +mDNSexport const mDNSv4Addr AllHosts_v4 = { { 224, 0, 0, 1 } }; // For NAT-PMP & PCP Annoucements +mDNSexport const mDNSv6Addr AllHosts_v6 = { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x01 } }; +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 +mDNSexport const mDNSEthAddr AllHosts_v6_Eth = { { 0x33, 0x33, 0x00, 0x00, 0x00, 0x01 } }; +mDNSexport const mDNSAddr AllDNSLinkGroup_v4 = { mDNSAddrType_IPv4, { { { 224, 0, 0, 251 } } } }; +//mDNSexport const mDNSAddr AllDNSLinkGroup_v4 = { mDNSAddrType_IPv4, { { { 224, 0, 0, 252 } } } }; // LLMNR +mDNSexport const mDNSAddr AllDNSLinkGroup_v6 = { mDNSAddrType_IPv6, { { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0xFB } } } }; +//mDNSexport const mDNSAddr AllDNSLinkGroup_v6 = { mDNSAddrType_IPv6, { { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x01,0x00,0x03 } } } }; // LLMNR + +mDNSexport const mDNSOpaque16 zeroID = { { 0, 0 } }; +mDNSexport const mDNSOpaque16 onesID = { { 255, 255 } }; +mDNSexport const mDNSOpaque16 QueryFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery, 0 } }; +mDNSexport const mDNSOpaque16 uQueryFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery | kDNSFlag0_RD, 0 } }; +mDNSexport const mDNSOpaque16 DNSSecQFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery | kDNSFlag0_RD, kDNSFlag1_CD } }; +mDNSexport const mDNSOpaque16 ResponseFlags = { { kDNSFlag0_QR_Response | kDNSFlag0_OP_StdQuery | kDNSFlag0_AA, 0 } }; +mDNSexport const mDNSOpaque16 UpdateReqFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_Update, 0 } }; +mDNSexport const mDNSOpaque16 UpdateRespFlags = { { kDNSFlag0_QR_Response | kDNSFlag0_OP_Update, 0 } }; + +mDNSexport const mDNSOpaque64 zeroOpaque64 = { { 0 } }; + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - General Utility Functions +#endif + +// return true for RFC1918 private addresses +mDNSexport mDNSBool mDNSv4AddrIsRFC1918(const mDNSv4Addr * const addr) +{ + return ((addr->b[0] == 10) || // 10/8 prefix + (addr->b[0] == 172 && (addr->b[1] & 0xF0) == 16) || // 172.16/12 + (addr->b[0] == 192 && addr->b[1] == 168)); // 192.168/16 +} + +mDNSexport void mDNSAddrMapIPv4toIPv6(mDNSv4Addr* in, mDNSv6Addr* out) +{ + out->l[0] = 0; + out->l[1] = 0; + out->w[4] = 0; + out->w[5] = 0xffff; + out->b[12] = in->b[0]; + out->b[13] = in->b[1]; + out->b[14] = in->b[2]; + out->b[15] = in->b[3]; +} + +mDNSexport mDNSBool mDNSAddrIPv4FromMappedIPv6(mDNSv6Addr *in, mDNSv4Addr* out) +{ + if (in->l[0] != 0 || in->l[1] != 0 || in->w[4] != 0 || in->w[5] != 0xffff) + return mDNSfalse; + + out->NotAnInteger = in->l[3]; + return mDNStrue; +} + +mDNSexport NetworkInterfaceInfo *GetFirstActiveInterface(NetworkInterfaceInfo *intf) +{ + while (intf && !intf->InterfaceActive) intf = intf->next; + return(intf); +} + +mDNSexport mDNSInterfaceID GetNextActiveInterfaceID(const NetworkInterfaceInfo *intf) +{ + const NetworkInterfaceInfo *next = GetFirstActiveInterface(intf->next); + if (next) return(next->InterfaceID);else return(mDNSNULL); +} + +mDNSexport mDNSu32 NumCacheRecordsForInterfaceID(const mDNS *const m, mDNSInterfaceID id) +{ + mDNSu32 slot, used = 0; + CacheGroup *cg; + const CacheRecord *rr; + FORALL_CACHERECORDS(slot, cg, rr) + { + if (rr->resrec.InterfaceID == id) + used++; + } + return(used); +} + +mDNSexport char *DNSTypeName(mDNSu16 rrtype) +{ + switch (rrtype) + { + case kDNSType_A: return("Addr"); + case kDNSType_NS: return("NS"); + case kDNSType_CNAME: return("CNAME"); + case kDNSType_SOA: return("SOA"); + case kDNSType_NULL: return("NULL"); + case kDNSType_PTR: return("PTR"); + case kDNSType_HINFO: return("HINFO"); + case kDNSType_TXT: return("TXT"); + case kDNSType_AAAA: return("AAAA"); + case kDNSType_SRV: return("SRV"); + case kDNSType_OPT: return("OPT"); + case kDNSType_NSEC: return("NSEC"); + case kDNSType_NSEC3: return("NSEC3"); + case kDNSType_NSEC3PARAM: return("NSEC3PARAM"); + case kDNSType_TSIG: return("TSIG"); + case kDNSType_RRSIG: return("RRSIG"); + case kDNSType_DNSKEY: return("DNSKEY"); + case kDNSType_DS: return("DS"); + case kDNSQType_ANY: return("ANY"); + default: { + static char buffer[16]; + mDNS_snprintf(buffer, sizeof(buffer), "TYPE%d", rrtype); + return(buffer); + } + } +} + +mDNSlocal char *DNSSECAlgName(mDNSu8 alg) +{ + switch (alg) + { + case CRYPTO_RSA_SHA1: return "RSA_SHA1"; + case CRYPTO_DSA_NSEC3_SHA1: return "DSA_NSEC3_SHA1"; + case CRYPTO_RSA_NSEC3_SHA1: return "RSA_NSEC3_SHA1"; + case CRYPTO_RSA_SHA256: return "RSA_SHA256"; + case CRYPTO_RSA_SHA512: return "RSA_SHA512"; + default: { + static char algbuffer[16]; + mDNS_snprintf(algbuffer, sizeof(algbuffer), "ALG%d", alg); + return(algbuffer); + } + } +} + +mDNSlocal char *DNSSECDigestName(mDNSu8 digest) +{ + switch (digest) + { + case SHA1_DIGEST_TYPE: return "SHA1"; + case SHA256_DIGEST_TYPE: return "SHA256"; + default: + { + static char digbuffer[16]; + mDNS_snprintf(digbuffer, sizeof(digbuffer), "DIG%d", digest); + return(digbuffer); + } + } +} + +mDNSexport mDNSu32 swap32(mDNSu32 x) +{ + mDNSu8 *ptr = (mDNSu8 *)&x; + return (mDNSu32)((mDNSu32)ptr[0] << 24 | (mDNSu32)ptr[1] << 16 | (mDNSu32)ptr[2] << 8 | ptr[3]); +} + +mDNSexport mDNSu16 swap16(mDNSu16 x) +{ + mDNSu8 *ptr = (mDNSu8 *)&x; + return (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); +} + +// RFC 4034 Appendix B: Get the keyid of a DNS KEY. It is not transmitted +// explicitly on the wire. +// +// Note: This just helps narrow down the list of keys to look at. It is possible +// for two DNS keys to have the same ID i.e., key ID is not a unqiue tag. We ignore +// MD5 keys. +// +// 1st argument - the RDATA part of the DNSKEY RR +// 2nd argument - the RDLENGTH +// +mDNSlocal mDNSu32 keytag(mDNSu8 *key, mDNSu32 keysize) +{ + unsigned long ac; + unsigned int i; + + for (ac = 0, i = 0; i < keysize; ++i) + ac += (i & 1) ? key[i] : key[i] << 8; + ac += (ac >> 16) & 0xFFFF; + return ac & 0xFFFF; +} + +mDNSexport int baseEncode(char *buffer, int blen, const mDNSu8 *data, int len, int encAlg) +{ + AlgContext *ctx; + mDNSu8 *outputBuffer; + int length; + + ctx = AlgCreate(ENC_ALG, encAlg); + if (!ctx) + { + LogMsg("baseEncode: AlgCreate failed\n"); + return 0; + } + AlgAdd(ctx, data, len); + outputBuffer = AlgEncode(ctx); + length = 0; + if (outputBuffer) + { + // Note: don't include any spaces in the format string below. This + // is also used by NSEC3 code for proving non-existence where it + // needs the base32 encoding without any spaces etc. + length = mDNS_snprintf(buffer, blen, "%s", outputBuffer); + } + AlgDestroy(ctx); + return length; +} + +mDNSlocal void PrintTypeBitmap(const mDNSu8 *bmap, int bitmaplen, char *const buffer, mDNSu32 length) +{ + int win, wlen, type; + + while (bitmaplen > 0) + { + int i; + + if (bitmaplen < 3) + { + LogMsg("PrintTypeBitmap: malformed bitmap, bitmaplen %d short", bitmaplen); + break; + } + + win = *bmap++; + wlen = *bmap++; + bitmaplen -= 2; + if (bitmaplen < wlen || wlen < 1 || wlen > 32) + { + LogInfo("PrintTypeBitmap: malformed nsec, bitmaplen %d wlen %d", bitmaplen, wlen); + break; + } + if (win < 0 || win >= 256) + { + LogInfo("PrintTypeBitmap: malformed nsec, bad window win %d", win); + break; + } + type = win * 256; + for (i = 0; i < wlen * 8; i++) + { + if (bmap[i>>3] & (128 >> (i&7))) + length += mDNS_snprintf(buffer+length, (MaxMsg - 1) - length, "%s ", DNSTypeName(type + i)); + } + bmap += wlen; + bitmaplen -= wlen; + } +} + +// Parse the fields beyond the base header. NSEC3 should have been validated. +mDNSexport void NSEC3Parse(const ResourceRecord *const rr, mDNSu8 **salt, int *hashLength, mDNSu8 **nxtName, int *bitmaplen, mDNSu8 **bitmap) +{ + const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; + rdataNSEC3 *nsec3 = (rdataNSEC3 *)rdb->data; + mDNSu8 *p = (mDNSu8 *)&nsec3->salt; + int hlen; + + if (salt) + { + if (nsec3->saltLength) + *salt = p; + else + *salt = mDNSNULL; + } + p += nsec3->saltLength; + // p is pointing at hashLength + hlen = (int)*p; + if (hashLength) + *hashLength = hlen; + p++; + if (nxtName) + *nxtName = p; + p += hlen; + if (bitmaplen) + *bitmaplen = rr->rdlength - (int)(p - rdb->data); + if (bitmap) + *bitmap = p; +} + +// Note slight bug: this code uses the rdlength from the ResourceRecord object, to display +// the rdata from the RDataBody object. Sometimes this could be the wrong length -- but as +// long as this routine is only used for debugging messages, it probably isn't a big problem. +mDNSexport char *GetRRDisplayString_rdb(const ResourceRecord *const rr, const RDataBody *const rd1, char *const buffer) +{ + const RDataBody2 *const rd = (RDataBody2 *)rd1; + #define RemSpc (MaxMsg-1-length) + char *ptr = buffer; + mDNSu32 length = mDNS_snprintf(buffer, MaxMsg-1, "%4d %##s %s ", rr->rdlength, rr->name->c, DNSTypeName(rr->rrtype)); + if (rr->RecordType == kDNSRecordTypePacketNegative) return(buffer); + if (!rr->rdlength) { mDNS_snprintf(buffer+length, RemSpc, "<< ZERO RDATA LENGTH >>"); return(buffer); } + + switch (rr->rrtype) + { + case kDNSType_A: mDNS_snprintf(buffer+length, RemSpc, "%.4a", &rd->ipv4); break; + + case kDNSType_NS: // Same as PTR + case kDNSType_CNAME: // Same as PTR + case kDNSType_PTR: mDNS_snprintf(buffer+length, RemSpc, "%##s", rd->name.c); break; + + case kDNSType_SOA: mDNS_snprintf(buffer+length, RemSpc, "%##s %##s %d %d %d %d %d", + rd->soa.mname.c, rd->soa.rname.c, + rd->soa.serial, rd->soa.refresh, rd->soa.retry, rd->soa.expire, rd->soa.min); + break; + + case kDNSType_HINFO: // Display this the same as TXT (show all constituent strings) + case kDNSType_TXT: { + const mDNSu8 *t = rd->txt.c; + while (t < rd->txt.c + rr->rdlength) + { + length += mDNS_snprintf(buffer+length, RemSpc, "%s%#s", t > rd->txt.c ? "¦" : "", t); + t += 1 + t[0]; + } + } break; + + case kDNSType_AAAA: mDNS_snprintf(buffer+length, RemSpc, "%.16a", &rd->ipv6); break; + case kDNSType_SRV: mDNS_snprintf(buffer+length, RemSpc, "%u %u %u %##s", + rd->srv.priority, rd->srv.weight, mDNSVal16(rd->srv.port), rd->srv.target.c); break; + + case kDNSType_OPT: { + const rdataOPT *opt; + const rdataOPT *const end = (const rdataOPT *)&rd->data[rr->rdlength]; + length += mDNS_snprintf(buffer+length, RemSpc, "Max %d", rr->rrclass); + for (opt = &rd->opt[0]; opt < end; opt++) + { + switch(opt->opt) + { + case kDNSOpt_LLQ: + length += mDNS_snprintf(buffer+length, RemSpc, " Vers %d", opt->u.llq.vers); + length += mDNS_snprintf(buffer+length, RemSpc, " Op %d", opt->u.llq.llqOp); + length += mDNS_snprintf(buffer+length, RemSpc, " Err/Port %d", opt->u.llq.err); + length += mDNS_snprintf(buffer+length, RemSpc, " ID %08X%08X", opt->u.llq.id.l[0], opt->u.llq.id.l[1]); + length += mDNS_snprintf(buffer+length, RemSpc, " Lease %d", opt->u.llq.llqlease); + break; + case kDNSOpt_Lease: + length += mDNS_snprintf(buffer+length, RemSpc, " Lease %d", opt->u.updatelease); + break; + case kDNSOpt_Owner: + length += mDNS_snprintf(buffer+length, RemSpc, " Vers %d", opt->u.owner.vers); + length += mDNS_snprintf(buffer+length, RemSpc, " Seq %3d", (mDNSu8)opt->u.owner.seq); // Display as unsigned + length += mDNS_snprintf(buffer+length, RemSpc, " MAC %.6a", opt->u.owner.HMAC.b); + if (opt->optlen >= DNSOpt_OwnerData_ID_Wake_Space-4) + { + length += mDNS_snprintf(buffer+length, RemSpc, " I-MAC %.6a", opt->u.owner.IMAC.b); + if (opt->optlen > DNSOpt_OwnerData_ID_Wake_Space-4) + length += mDNS_snprintf(buffer+length, RemSpc, " Password %.6a", opt->u.owner.password.b); + } + break; + case kDNSOpt_Trace: + length += mDNS_snprintf(buffer+length, RemSpc, " Platform %d", opt->u.tracer.platf); + length += mDNS_snprintf(buffer+length, RemSpc, " mDNSVers %d", opt->u.tracer.mDNSv); + break; + default: + length += mDNS_snprintf(buffer+length, RemSpc, " Unknown %d", opt->opt); + break; + } + } + } + break; + + case kDNSType_NSEC: { + domainname *next = (domainname *)rd->data; + int len, bitmaplen; + mDNSu8 *bmap; + len = DomainNameLength(next); + bitmaplen = rr->rdlength - len; + bmap = (mDNSu8 *)((mDNSu8 *)next + len); + + if (UNICAST_NSEC(rr)) + length += mDNS_snprintf(buffer+length, RemSpc, "%##s ", next->c); + PrintTypeBitmap(bmap, bitmaplen, buffer, length); + + } + break; + case kDNSType_NSEC3: { + rdataNSEC3 *nsec3 = (rdataNSEC3 *)rd->data; + const mDNSu8 *p = (mDNSu8 *)&nsec3->salt; + int hashLength, bitmaplen, i; + + length += mDNS_snprintf(buffer+length, RemSpc, "\t%s %d %d ", + DNSSECDigestName(nsec3->alg), nsec3->flags, swap16(nsec3->iterations)); + + if (!nsec3->saltLength) + { + length += mDNS_snprintf(buffer+length, RemSpc, "-"); + } + else + { + for (i = 0; i < nsec3->saltLength; i++) + { + length += mDNS_snprintf(buffer+length, RemSpc, "%x", p[i]); + } + } + + // put a space at the end + length += mDNS_snprintf(buffer+length, RemSpc, " "); + + p += nsec3->saltLength; + // p is pointing at hashLength + hashLength = (int)*p++; + + length += baseEncode(buffer + length, RemSpc, p, hashLength, ENC_BASE32); + + // put a space at the end + length += mDNS_snprintf(buffer+length, RemSpc, " "); + + p += hashLength; + bitmaplen = rr->rdlength - (int)(p - rd->data); + PrintTypeBitmap(p, bitmaplen, buffer, length); + } + break; + case kDNSType_RRSIG: { + rdataRRSig *rrsig = (rdataRRSig *)rd->data; + mDNSu8 expTimeBuf[64]; + mDNSu8 inceptTimeBuf[64]; + unsigned long inceptClock; + unsigned long expClock; + int len; + + expClock = (unsigned long)swap32(rrsig->sigExpireTime); + mDNSPlatformFormatTime(expClock, expTimeBuf, sizeof(expTimeBuf)); + + inceptClock = (unsigned long)swap32(rrsig->sigInceptTime); + mDNSPlatformFormatTime(inceptClock, inceptTimeBuf, sizeof(inceptTimeBuf)); + + length += mDNS_snprintf(buffer+length, RemSpc, "\t%s %s %d %d %s %s %d %##s ", + DNSTypeName(swap16(rrsig->typeCovered)), DNSSECAlgName(rrsig->alg), rrsig->labels, swap32(rrsig->origTTL), + expTimeBuf, inceptTimeBuf, swap16(rrsig->keyTag), ((domainname *)(&rrsig->signerName))->c); + + len = DomainNameLength((domainname *)&rrsig->signerName); + length += baseEncode(buffer + length, RemSpc, (const mDNSu8 *)(rd->data + len + RRSIG_FIXED_SIZE), + rr->rdlength - (len + RRSIG_FIXED_SIZE), ENC_BASE64); + } + break; + case kDNSType_DNSKEY: { + rdataDNSKey *rrkey = (rdataDNSKey *)rd->data; + length += mDNS_snprintf(buffer+length, RemSpc, "\t%d %d %s %u ", swap16(rrkey->flags), rrkey->proto, + DNSSECAlgName(rrkey->alg), (unsigned int)keytag((mDNSu8 *)rrkey, rr->rdlength)); + length += baseEncode(buffer + length, RemSpc, (const mDNSu8 *)(rd->data + DNSKEY_FIXED_SIZE), + rr->rdlength - DNSKEY_FIXED_SIZE, ENC_BASE64); + } + break; + case kDNSType_DS: { + mDNSu8 *p; + int i; + rdataDS *rrds = (rdataDS *)rd->data; + + length += mDNS_snprintf(buffer+length, RemSpc, "\t%s\t%d\t%s ", DNSSECAlgName(rrds->alg), swap16(rrds->keyTag), + DNSSECDigestName(rrds->digestType)); + + p = (mDNSu8 *)(rd->data + DS_FIXED_SIZE); + for (i = 0; i < (rr->rdlength - DS_FIXED_SIZE); i++) + { + length += mDNS_snprintf(buffer+length, RemSpc, "%x", p[i]); + } + } + break; + + default: mDNS_snprintf(buffer+length, RemSpc, "RDLen %d: %s", rr->rdlength, rd->data); + // Really should scan buffer to check if text is valid UTF-8 and only replace with dots if not + for (ptr = buffer; *ptr; ptr++) if (*ptr < ' ') *ptr = '.'; + break; + } + return(buffer); +} + +// See comments in mDNSEmbeddedAPI.h +#if _PLATFORM_HAS_STRONG_PRNG_ +#define mDNSRandomNumber mDNSPlatformRandomNumber +#else +mDNSlocal mDNSu32 mDNSRandomFromSeed(mDNSu32 seed) +{ + return seed * 21 + 1; +} + +mDNSlocal mDNSu32 mDNSMixRandomSeed(mDNSu32 seed, mDNSu8 iteration) +{ + return iteration ? mDNSMixRandomSeed(mDNSRandomFromSeed(seed), --iteration) : seed; +} + +mDNSlocal mDNSu32 mDNSRandomNumber() +{ + static mDNSBool seeded = mDNSfalse; + static mDNSu32 seed = 0; + if (!seeded) + { + seed = mDNSMixRandomSeed(mDNSPlatformRandomSeed(), 100); + seeded = mDNStrue; + } + return (seed = mDNSRandomFromSeed(seed)); +} +#endif // ! _PLATFORM_HAS_STRONG_PRNG_ + +mDNSexport mDNSu32 mDNSRandom(mDNSu32 max) // Returns pseudo-random result from zero to max inclusive +{ + mDNSu32 ret = 0; + mDNSu32 mask = 1; + + while (mask < max) mask = (mask << 1) | 1; + + do ret = mDNSRandomNumber() & mask; + while (ret > max); + + return ret; +} + +mDNSexport mDNSBool mDNSSameAddress(const mDNSAddr *ip1, const mDNSAddr *ip2) +{ + if (ip1->type == ip2->type) + { + switch (ip1->type) + { + case mDNSAddrType_None: return(mDNStrue); // Empty addresses have no data and are therefore always equal + case mDNSAddrType_IPv4: return (mDNSBool)(mDNSSameIPv4Address(ip1->ip.v4, ip2->ip.v4)); + case mDNSAddrType_IPv6: return (mDNSBool)(mDNSSameIPv6Address(ip1->ip.v6, ip2->ip.v6)); + } + } + return(mDNSfalse); +} + +mDNSexport mDNSBool mDNSAddrIsDNSMulticast(const mDNSAddr *ip) +{ + switch(ip->type) + { + case mDNSAddrType_IPv4: return (mDNSBool)(mDNSSameIPv4Address(ip->ip.v4, AllDNSLinkGroup_v4.ip.v4)); + case mDNSAddrType_IPv6: return (mDNSBool)(mDNSSameIPv6Address(ip->ip.v6, AllDNSLinkGroup_v6.ip.v6)); + default: return(mDNSfalse); + } +} + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - Domain Name Utility Functions +#endif + +mDNSexport mDNSBool SameDomainLabel(const mDNSu8 *a, const mDNSu8 *b) +{ + int i; + const int len = *a++; + + if (len > MAX_DOMAIN_LABEL) + { debugf("Malformed label (too long)"); return(mDNSfalse); } + + if (len != *b++) return(mDNSfalse); + for (i=0; i<len; i++) + { + mDNSu8 ac = *a++; + mDNSu8 bc = *b++; + if (mDNSIsUpperCase(ac)) ac += 'a' - 'A'; + if (mDNSIsUpperCase(bc)) bc += 'a' - 'A'; + if (ac != bc) return(mDNSfalse); + } + return(mDNStrue); +} + +mDNSexport mDNSBool SameDomainName(const domainname *const d1, const domainname *const d2) +{ + const mDNSu8 * a = d1->c; + const mDNSu8 * b = d2->c; + const mDNSu8 *const max = d1->c + MAX_DOMAIN_NAME; // Maximum that's valid + + while (*a || *b) + { + if (a + 1 + *a >= max) + { debugf("Malformed domain name (more than 256 characters)"); return(mDNSfalse); } + if (!SameDomainLabel(a, b)) return(mDNSfalse); + a += 1 + *a; + b += 1 + *b; + } + + return(mDNStrue); +} + +mDNSexport mDNSBool SameDomainNameCS(const domainname *const d1, const domainname *const d2) +{ + mDNSu16 l1 = DomainNameLength(d1); + mDNSu16 l2 = DomainNameLength(d2); + return(l1 <= MAX_DOMAIN_NAME && l1 == l2 && mDNSPlatformMemSame(d1, d2, l1)); +} + +mDNSexport mDNSBool IsLocalDomain(const domainname *d) +{ + // Domains that are defined to be resolved via link-local multicast are: + // local., 254.169.in-addr.arpa., and {8,9,A,B}.E.F.ip6.arpa. + static const domainname *nL = (const domainname*)"\x5" "local"; + static const domainname *nR = (const domainname*)"\x3" "254" "\x3" "169" "\x7" "in-addr" "\x4" "arpa"; + static const domainname *n8 = (const domainname*)"\x1" "8" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; + static const domainname *n9 = (const domainname*)"\x1" "9" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; + static const domainname *nA = (const domainname*)"\x1" "a" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; + static const domainname *nB = (const domainname*)"\x1" "b" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; + + const domainname *d1, *d2, *d3, *d4, *d5; // Top-level domain, second-level domain, etc. + d1 = d2 = d3 = d4 = d5 = mDNSNULL; + while (d->c[0]) + { + d5 = d4; d4 = d3; d3 = d2; d2 = d1; d1 = d; + d = (const domainname*)(d->c + 1 + d->c[0]); + } + + if (d1 && SameDomainName(d1, nL)) return(mDNStrue); + if (d4 && SameDomainName(d4, nR)) return(mDNStrue); + if (d5 && SameDomainName(d5, n8)) return(mDNStrue); + if (d5 && SameDomainName(d5, n9)) return(mDNStrue); + if (d5 && SameDomainName(d5, nA)) return(mDNStrue); + if (d5 && SameDomainName(d5, nB)) return(mDNStrue); + return(mDNSfalse); +} + +mDNSexport const mDNSu8 *LastLabel(const domainname *d) +{ + const mDNSu8 *p = d->c; + while (d->c[0]) + { + p = d->c; + d = (const domainname*)(d->c + 1 + d->c[0]); + } + return(p); +} + +// Returns length of a domain name INCLUDING the byte for the final null label +// e.g. for the root label "." it returns one +// For the FQDN "com." it returns 5 (length byte, three data bytes, final zero) +// Legal results are 1 (just root label) to 256 (MAX_DOMAIN_NAME) +// If the given domainname is invalid, result is 257 (MAX_DOMAIN_NAME+1) +mDNSexport mDNSu16 DomainNameLengthLimit(const domainname *const name, const mDNSu8 *limit) +{ + const mDNSu8 *src = name->c; + while (src < limit && *src <= MAX_DOMAIN_LABEL) + { + if (*src == 0) return((mDNSu16)(src - name->c + 1)); + src += 1 + *src; + } + return(MAX_DOMAIN_NAME+1); +} + +// CompressedDomainNameLength returns the length of a domain name INCLUDING the byte +// for the final null label, e.g. for the root label "." it returns one. +// E.g. for the FQDN "foo.com." it returns 9 +// (length, three data bytes, length, three more data bytes, final zero). +// In the case where a parent domain name is provided, and the given name is a child +// of that parent, CompressedDomainNameLength returns the length of the prefix portion +// of the child name, plus TWO bytes for the compression pointer. +// E.g. for the name "foo.com." with parent "com.", it returns 6 +// (length, three data bytes, two-byte compression pointer). +mDNSexport mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent) +{ + const mDNSu8 *src = name->c; + if (parent && parent->c[0] == 0) parent = mDNSNULL; + while (*src) + { + if (*src > MAX_DOMAIN_LABEL) return(MAX_DOMAIN_NAME+1); + if (parent && SameDomainName((const domainname *)src, parent)) return((mDNSu16)(src - name->c + 2)); + src += 1 + *src; + if (src - name->c >= MAX_DOMAIN_NAME) return(MAX_DOMAIN_NAME+1); + } + return((mDNSu16)(src - name->c + 1)); +} + +// CountLabels() returns number of labels in name, excluding final root label +// (e.g. for "apple.com." CountLabels returns 2.) +mDNSexport int CountLabels(const domainname *d) +{ + int count = 0; + const mDNSu8 *ptr; + for (ptr = d->c; *ptr; ptr = ptr + ptr[0] + 1) count++; + return count; +} + +// SkipLeadingLabels skips over the first 'skip' labels in the domainname, +// returning a pointer to the suffix with 'skip' labels removed. +mDNSexport const domainname *SkipLeadingLabels(const domainname *d, int skip) +{ + while (skip > 0 && d->c[0]) { d = (const domainname *)(d->c + 1 + d->c[0]); skip--; } + return(d); +} + +// AppendLiteralLabelString appends a single label to an existing (possibly empty) domainname. +// The C string contains the label as-is, with no escaping, etc. +// Any dots in the name are literal dots, not label separators +// If successful, AppendLiteralLabelString returns a pointer to the next unused byte +// in the domainname bufer (i.e. the next byte after the terminating zero). +// If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) +// AppendLiteralLabelString returns mDNSNULL. +mDNSexport mDNSu8 *AppendLiteralLabelString(domainname *const name, const char *cstr) +{ + mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name + const mDNSu8 *const lim1 = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero) + const mDNSu8 *const lim2 = ptr + 1 + MAX_DOMAIN_LABEL; + const mDNSu8 *const lim = (lim1 < lim2) ? lim1 : lim2; + mDNSu8 *lengthbyte = ptr++; // Record where the length is going to go + + while (*cstr && ptr < lim) *ptr++ = (mDNSu8)*cstr++; // Copy the data + *lengthbyte = (mDNSu8)(ptr - lengthbyte - 1); // Fill in the length byte + *ptr++ = 0; // Put the null root label on the end + if (*cstr) return(mDNSNULL); // Failure: We didn't successfully consume all input + else return(ptr); // Success: return new value of ptr +} + +// AppendDNSNameString appends zero or more labels to an existing (possibly empty) domainname. +// The C string is in conventional DNS syntax: +// Textual labels, escaped as necessary using the usual DNS '\' notation, separated by dots. +// If successful, AppendDNSNameString returns a pointer to the next unused byte +// in the domainname bufer (i.e. the next byte after the terminating zero). +// If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) +// AppendDNSNameString returns mDNSNULL. +mDNSexport mDNSu8 *AppendDNSNameString(domainname *const name, const char *cstring) +{ + const char *cstr = cstring; + mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name + const mDNSu8 *const lim = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero) + while (*cstr && ptr < lim) // While more characters, and space to put them... + { + mDNSu8 *lengthbyte = ptr++; // Record where the length is going to go + if (*cstr == '.') { LogMsg("AppendDNSNameString: Illegal empty label in name \"%s\"", cstring); return(mDNSNULL); } + while (*cstr && *cstr != '.' && ptr < lim) // While we have characters in the label... + { + mDNSu8 c = (mDNSu8)*cstr++; // Read the character + if (c == '\\') // If escape character, check next character + { + c = (mDNSu8)*cstr++; // Assume we'll just take the next character + if (mDNSIsDigit(cstr[-1]) && mDNSIsDigit(cstr[0]) && mDNSIsDigit(cstr[1])) + { // If three decimal digits, + int v0 = cstr[-1] - '0'; // then interpret as three-digit decimal + int v1 = cstr[ 0] - '0'; + int v2 = cstr[ 1] - '0'; + int val = v0 * 100 + v1 * 10 + v2; + if (val <= 255) { c = (mDNSu8)val; cstr += 2; } // If valid three-digit decimal value, use it + } + } + *ptr++ = c; // Write the character + } + if (*cstr) cstr++; // Skip over the trailing dot (if present) + if (ptr - lengthbyte - 1 > MAX_DOMAIN_LABEL) // If illegal label, abort + return(mDNSNULL); + *lengthbyte = (mDNSu8)(ptr - lengthbyte - 1); // Fill in the length byte + } + + *ptr++ = 0; // Put the null root label on the end + if (*cstr) return(mDNSNULL); // Failure: We didn't successfully consume all input + else return(ptr); // Success: return new value of ptr +} + +// AppendDomainLabel appends a single label to a name. +// If successful, AppendDomainLabel returns a pointer to the next unused byte +// in the domainname bufer (i.e. the next byte after the terminating zero). +// If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) +// AppendDomainLabel returns mDNSNULL. +mDNSexport mDNSu8 *AppendDomainLabel(domainname *const name, const domainlabel *const label) +{ + int i; + mDNSu8 *ptr = name->c + DomainNameLength(name) - 1; + + // Check label is legal + if (label->c[0] > MAX_DOMAIN_LABEL) return(mDNSNULL); + + // Check that ptr + length byte + data bytes + final zero does not exceed our limit + if (ptr + 1 + label->c[0] + 1 > name->c + MAX_DOMAIN_NAME) return(mDNSNULL); + + for (i=0; i<=label->c[0]; i++) *ptr++ = label->c[i]; // Copy the label data + *ptr++ = 0; // Put the null root label on the end + return(ptr); +} + +mDNSexport mDNSu8 *AppendDomainName(domainname *const name, const domainname *const append) +{ + mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name + const mDNSu8 *const lim = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero) + const mDNSu8 * src = append->c; + while (src[0]) + { + int i; + if (ptr + 1 + src[0] > lim) return(mDNSNULL); + for (i=0; i<=src[0]; i++) *ptr++ = src[i]; + *ptr = 0; // Put the null root label on the end + src += i; + } + return(ptr); +} + +// MakeDomainLabelFromLiteralString makes a single domain label from a single literal C string (with no escaping). +// If successful, MakeDomainLabelFromLiteralString returns mDNStrue. +// If unable to convert the whole string to a legal domain label (i.e. because length is more than 63 bytes) then +// MakeDomainLabelFromLiteralString makes a legal domain label from the first 63 bytes of the string and returns mDNSfalse. +// In some cases silently truncated oversized names to 63 bytes is acceptable, so the return result may be ignored. +// In other cases silent truncation may not be acceptable, so in those cases the calling function needs to check the return result. +mDNSexport mDNSBool MakeDomainLabelFromLiteralString(domainlabel *const label, const char *cstr) +{ + mDNSu8 * ptr = label->c + 1; // Where we're putting it + const mDNSu8 *const limit = label->c + 1 + MAX_DOMAIN_LABEL; // The maximum we can put + while (*cstr && ptr < limit) *ptr++ = (mDNSu8)*cstr++; // Copy the label + label->c[0] = (mDNSu8)(ptr - label->c - 1); // Set the length byte + return(*cstr == 0); // Return mDNStrue if we successfully consumed all input +} + +// MakeDomainNameFromDNSNameString makes a native DNS-format domainname from a C string. +// The C string is in conventional DNS syntax: +// Textual labels, escaped as necessary using the usual DNS '\' notation, separated by dots. +// If successful, MakeDomainNameFromDNSNameString returns a pointer to the next unused byte +// in the domainname bufer (i.e. the next byte after the terminating zero). +// If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) +// MakeDomainNameFromDNSNameString returns mDNSNULL. +mDNSexport mDNSu8 *MakeDomainNameFromDNSNameString(domainname *const name, const char *cstr) +{ + name->c[0] = 0; // Make an empty domain name + return(AppendDNSNameString(name, cstr)); // And then add this string to it +} + +mDNSexport char *ConvertDomainLabelToCString_withescape(const domainlabel *const label, char *ptr, char esc) +{ + const mDNSu8 * src = label->c; // Domain label we're reading + const mDNSu8 len = *src++; // Read length of this (non-null) label + const mDNSu8 *const end = src + len; // Work out where the label ends + if (len > MAX_DOMAIN_LABEL) return(mDNSNULL); // If illegal label, abort + while (src < end) // While we have characters in the label + { + mDNSu8 c = *src++; + if (esc) + { + if (c == '.' || c == esc) // If character is a dot or the escape character + *ptr++ = esc; // Output escape character + else if (c <= ' ') // If non-printing ascii, + { // Output decimal escape sequence + *ptr++ = esc; + *ptr++ = (char) ('0' + (c / 100) ); + *ptr++ = (char) ('0' + (c / 10) % 10); + c = (mDNSu8)('0' + (c ) % 10); + } + } + *ptr++ = (char)c; // Copy the character + } + *ptr = 0; // Null-terminate the string + return(ptr); // and return +} + +// Note: To guarantee that there will be no possible overrun, cstr must be at least MAX_ESCAPED_DOMAIN_NAME (1009 bytes) +mDNSexport char *ConvertDomainNameToCString_withescape(const domainname *const name, char *ptr, char esc) +{ + const mDNSu8 *src = name->c; // Domain name we're reading + const mDNSu8 *const max = name->c + MAX_DOMAIN_NAME; // Maximum that's valid + + if (*src == 0) *ptr++ = '.'; // Special case: For root, just write a dot + + while (*src) // While more characters in the domain name + { + if (src + 1 + *src >= max) return(mDNSNULL); + ptr = ConvertDomainLabelToCString_withescape((const domainlabel *)src, ptr, esc); + if (!ptr) return(mDNSNULL); + src += 1 + *src; + *ptr++ = '.'; // Write the dot after the label + } + + *ptr++ = 0; // Null-terminate the string + return(ptr); // and return +} + +// RFC 1034 rules: +// Host names must start with a letter, end with a letter or digit, +// and have as interior characters only letters, digits, and hyphen. +// This was subsequently modified in RFC 1123 to allow the first character to be either a letter or a digit + +mDNSexport void ConvertUTF8PstringToRFC1034HostLabel(const mDNSu8 UTF8Name[], domainlabel *const hostlabel) +{ + const mDNSu8 * src = &UTF8Name[1]; + const mDNSu8 *const end = &UTF8Name[1] + UTF8Name[0]; + mDNSu8 * ptr = &hostlabel->c[1]; + const mDNSu8 *const lim = &hostlabel->c[1] + MAX_DOMAIN_LABEL; + while (src < end) + { + // Delete apostrophes from source name + if (src[0] == '\'') { src++; continue; } // Standard straight single quote + if (src + 2 < end && src[0] == 0xE2 && src[1] == 0x80 && src[2] == 0x99) + { src += 3; continue; } // Unicode curly apostrophe + if (ptr < lim) + { + if (mDNSValidHostChar(*src, (ptr > &hostlabel->c[1]), (src < end-1))) *ptr++ = *src; + else if (ptr > &hostlabel->c[1] && ptr[-1] != '-') *ptr++ = '-'; + } + src++; + } + while (ptr > &hostlabel->c[1] && ptr[-1] == '-') ptr--; // Truncate trailing '-' marks + hostlabel->c[0] = (mDNSu8)(ptr - &hostlabel->c[1]); +} + +#define ValidTransportProtocol(X) ( (X)[0] == 4 && (X)[1] == '_' && \ + ((((X)[2] | 0x20) == 'u' && ((X)[3] | 0x20) == 'd') || (((X)[2] | 0x20) == 't' && ((X)[3] | 0x20) == 'c')) && \ + ((X)[4] | 0x20) == 'p') + +mDNSexport mDNSu8 *ConstructServiceName(domainname *const fqdn, + const domainlabel *name, const domainname *type, const domainname *const domain) +{ + int i, len; + mDNSu8 *dst = fqdn->c; + const mDNSu8 *src; + const char *errormsg; +#if APPLE_OSX_mDNSResponder + mDNSBool loggedUnderscore = mDNSfalse; + static char typeBuf[MAX_ESCAPED_DOMAIN_NAME]; +#endif + + // In the case where there is no name (and ONLY in that case), + // a single-label subtype is allowed as the first label of a three-part "type" + if (!name && type) + { + const mDNSu8 *s0 = type->c; + if (s0[0] && s0[0] < 0x40) // If legal first label (at least one character, and no more than 63) + { + const mDNSu8 * s1 = s0 + 1 + s0[0]; + if (s1[0] && s1[0] < 0x40) // and legal second label (at least one character, and no more than 63) + { + const mDNSu8 *s2 = s1 + 1 + s1[0]; + if (s2[0] && s2[0] < 0x40 && s2[1+s2[0]] == 0) // and we have three and only three labels + { + static const mDNSu8 SubTypeLabel[5] = mDNSSubTypeLabel; + src = s0; // Copy the first label + len = *src; + for (i=0; i <= len; i++) *dst++ = *src++; + for (i=0; i < (int)sizeof(SubTypeLabel); i++) *dst++ = SubTypeLabel[i]; + type = (const domainname *)s1; + + // Special support to enable the DNSServiceBrowse call made by Bonjour Browser + // For these queries, we retract the "._sub" we just added between the subtype and the main type + // Remove after Bonjour Browser is updated to use DNSServiceQueryRecord instead of DNSServiceBrowse + if (SameDomainName((domainname*)s0, (const domainname*)"\x09_services\x07_dns-sd\x04_udp")) + dst -= sizeof(SubTypeLabel); + } + } + } + } + + if (name && name->c[0]) + { + src = name->c; // Put the service name into the domain name + len = *src; + if (len >= 0x40) { errormsg = "Service instance name too long"; goto fail; } + for (i=0; i<=len; i++) *dst++ = *src++; + } + else + name = (domainlabel*)""; // Set this up to be non-null, to avoid errors if we have to call LogMsg() below + + src = type->c; // Put the service type into the domain name + len = *src; + if (len < 2 || len > 16) + { + LogMsg("Bad service type in %#s.%##s%##s Application protocol name must be underscore plus 1-15 characters. " + "See <http://www.dns-sd.org/ServiceTypes.html>", name->c, type->c, domain->c); +#if APPLE_OSX_mDNSResponder + ConvertDomainNameToCString(type, typeBuf); + mDNSASLLog(mDNSNULL, "serviceType.nameTooLong", "noop", typeBuf, ""); +#endif + } + if (len < 2 || len >= 0x40 || (len > 16 && !SameDomainName(domain, &localdomain))) return(mDNSNULL); + if (src[1] != '_') { errormsg = "Application protocol name must begin with underscore"; goto fail; } + for (i=2; i<=len; i++) + { + // Letters and digits are allowed anywhere + if (mDNSIsLetter(src[i]) || mDNSIsDigit(src[i])) continue; + // Hyphens are only allowed as interior characters + // Underscores are not supposed to be allowed at all, but for backwards compatibility with some old products we do allow them, + // with the same rule as hyphens + if ((src[i] == '-' || src[i] == '_') && i > 2 && i < len) + { +#if APPLE_OSX_mDNSResponder + if (src[i] == '_' && loggedUnderscore == mDNSfalse) + { + ConvertDomainNameToCString(type, typeBuf); + mDNSASLLog(mDNSNULL, "serviceType.nameWithUnderscore", "noop", typeBuf, ""); + loggedUnderscore = mDNStrue; + } +#endif + continue; + } + errormsg = "Application protocol name must contain only letters, digits, and hyphens"; +#if APPLE_OSX_mDNSResponder + { + ConvertDomainNameToCString(type, typeBuf); + mDNSASLLog(mDNSNULL, "serviceType.nameWithIllegalCharacters", "noop", typeBuf, ""); + } +#endif + goto fail; + } + for (i=0; i<=len; i++) *dst++ = *src++; + + len = *src; + if (!ValidTransportProtocol(src)) { errormsg = "Transport protocol name must be _udp or _tcp"; goto fail; } + for (i=0; i<=len; i++) *dst++ = *src++; + + if (*src) { errormsg = "Service type must have only two labels"; goto fail; } + + *dst = 0; + if (!domain->c[0]) { errormsg = "Service domain must be non-empty"; goto fail; } + if (SameDomainName(domain, (const domainname*)"\x05" "local" "\x04" "arpa")) + { errormsg = "Illegal domain \"local.arpa.\" Use \"local.\" (or empty string)"; goto fail; } + dst = AppendDomainName(fqdn, domain); + if (!dst) { errormsg = "Service domain too long"; goto fail; } + return(dst); + +fail: + LogMsg("ConstructServiceName: %s: %#s.%##s%##s", errormsg, name->c, type->c, domain->c); + return(mDNSNULL); +} + +// A service name has the form: instance.application-protocol.transport-protocol.domain +// DeconstructServiceName is currently fairly forgiving: It doesn't try to enforce character +// set or length limits for the protocol names, and the final domain is allowed to be empty. +// However, if the given FQDN doesn't contain at least three labels, +// DeconstructServiceName will reject it and return mDNSfalse. +mDNSexport mDNSBool DeconstructServiceName(const domainname *const fqdn, + domainlabel *const name, domainname *const type, domainname *const domain) +{ + int i, len; + const mDNSu8 *src = fqdn->c; + const mDNSu8 *max = fqdn->c + MAX_DOMAIN_NAME; + mDNSu8 *dst; + + dst = name->c; // Extract the service name + len = *src; + if (!len) { debugf("DeconstructServiceName: FQDN empty!"); return(mDNSfalse); } + if (len >= 0x40) { debugf("DeconstructServiceName: Instance name too long"); return(mDNSfalse); } + for (i=0; i<=len; i++) *dst++ = *src++; + + dst = type->c; // Extract the service type + len = *src; + if (!len) { debugf("DeconstructServiceName: FQDN contains only one label!"); return(mDNSfalse); } + if (len >= 0x40) { debugf("DeconstructServiceName: Application protocol name too long"); return(mDNSfalse); } + if (src[1] != '_') { debugf("DeconstructServiceName: No _ at start of application protocol"); return(mDNSfalse); } + for (i=0; i<=len; i++) *dst++ = *src++; + + len = *src; + if (!len) { debugf("DeconstructServiceName: FQDN contains only two labels!"); return(mDNSfalse); } + if (!ValidTransportProtocol(src)) + { debugf("DeconstructServiceName: Transport protocol must be _udp or _tcp"); return(mDNSfalse); } + for (i=0; i<=len; i++) *dst++ = *src++; + *dst++ = 0; // Put terminator on the end of service type + + dst = domain->c; // Extract the service domain + while (*src) + { + len = *src; + if (len >= 0x40) + { debugf("DeconstructServiceName: Label in service domain too long"); return(mDNSfalse); } + if (src + 1 + len + 1 >= max) + { debugf("DeconstructServiceName: Total service domain too long"); return(mDNSfalse); } + for (i=0; i<=len; i++) *dst++ = *src++; + } + *dst++ = 0; // Put the null root label on the end + + return(mDNStrue); +} + +mDNSexport mStatus DNSNameToLowerCase(domainname *d, domainname *result) +{ + const mDNSu8 *a = d->c; + mDNSu8 *b = result->c; + const mDNSu8 *const max = d->c + MAX_DOMAIN_NAME; + int i, len; + + while (*a) + { + if (a + 1 + *a >= max) + { + LogMsg("DNSNameToLowerCase: ERROR!! Malformed Domain name"); + return mStatus_BadParamErr; + } + len = *a++; + *b++ = len; + for (i = 0; i < len; i++) + { + mDNSu8 ac = *a++; + if (mDNSIsUpperCase(ac)) ac += 'a' - 'A'; + *b++ = ac; + } + } + *b = 0; + + return mStatus_NoError; +} + +mDNSexport const mDNSu8 *NSEC3HashName(const domainname *name, rdataNSEC3 *nsec3, const mDNSu8 *AnonData, int AnonDataLen, + const mDNSu8 hash[NSEC3_MAX_HASH_LEN], int *dlen) +{ + AlgContext *ctx; + int i; + domainname lname; + mDNSu8 *p = (mDNSu8 *)&nsec3->salt; + const mDNSu8 *digest; + int digestlen; + mDNSBool first = mDNStrue; + + if (DNSNameToLowerCase((domainname *)name, &lname) != mStatus_NoError) + { + LogMsg("NSEC3HashName: ERROR!! DNSNameToLowerCase failed"); + return mDNSNULL; + } + + digest = lname.c; + digestlen = DomainNameLength(&lname); + + // Note that it is "i <=". The first iteration is for digesting the name and salt. + // The iteration count does not include that. + for (i = 0; i <= swap16(nsec3->iterations); i++) + { + ctx = AlgCreate(DIGEST_ALG, nsec3->alg); + if (!ctx) + { + LogMsg("NSEC3HashName: ERROR!! Cannot allocate context"); + return mDNSNULL; + } + + AlgAdd(ctx, digest, digestlen); + if (nsec3->saltLength) + AlgAdd(ctx, p, nsec3->saltLength); + if (AnonDataLen) + AlgAdd(ctx, AnonData, AnonDataLen); + if (first) + { + first = mDNSfalse; + digest = hash; + digestlen = AlgLength(ctx); + } + AlgFinal(ctx, (void *)digest, digestlen); + AlgDestroy(ctx); + } + *dlen = digestlen; + return digest; +} + +// Notes on UTF-8: +// 0xxxxxxx represents a 7-bit ASCII value from 0x00 to 0x7F +// 10xxxxxx is a continuation byte of a multi-byte character +// 110xxxxx is the first byte of a 2-byte character (11 effective bits; values 0x 80 - 0x 800-1) +// 1110xxxx is the first byte of a 3-byte character (16 effective bits; values 0x 800 - 0x 10000-1) +// 11110xxx is the first byte of a 4-byte character (21 effective bits; values 0x 10000 - 0x 200000-1) +// 111110xx is the first byte of a 5-byte character (26 effective bits; values 0x 200000 - 0x 4000000-1) +// 1111110x is the first byte of a 6-byte character (31 effective bits; values 0x4000000 - 0x80000000-1) +// +// UTF-16 surrogate pairs are used in UTF-16 to encode values larger than 0xFFFF. +// Although UTF-16 surrogate pairs are not supposed to appear in legal UTF-8, we want to be defensive +// about that too. (See <http://www.unicode.org/faq/utf_bom.html#34>, "What are surrogates?") +// The first of pair is a UTF-16 value in the range 0xD800-0xDBFF (11101101 1010xxxx 10xxxxxx in UTF-8), +// and the second is a UTF-16 value in the range 0xDC00-0xDFFF (11101101 1011xxxx 10xxxxxx in UTF-8). + +mDNSexport mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max) +{ + if (length > max) + { + mDNSu8 c1 = string[max]; // First byte after cut point + mDNSu8 c2 = (max+1 < length) ? string[max+1] : (mDNSu8)0xB0; // Second byte after cut point + length = max; // Trim length down + while (length > 0) + { + // Check if the byte right after the chop point is a UTF-8 continuation byte, + // or if the character right after the chop point is the second of a UTF-16 surrogate pair. + // If so, then we continue to chop more bytes until we get to a legal chop point. + mDNSBool continuation = ((c1 & 0xC0) == 0x80); + mDNSBool secondsurrogate = (c1 == 0xED && (c2 & 0xF0) == 0xB0); + if (!continuation && !secondsurrogate) break; + c2 = c1; + c1 = string[--length]; + } + // Having truncated characters off the end of our string, also cut off any residual white space + while (length > 0 && string[length-1] <= ' ') length--; + } + return(length); +} + +// Returns true if a rich text label ends in " (nnn)", or if an RFC 1034 +// name ends in "-nnn", where n is some decimal number. +mDNSexport mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText) +{ + mDNSu16 l = name->c[0]; + + if (RichText) + { + if (l < 4) return mDNSfalse; // Need at least " (2)" + if (name->c[l--] != ')') return mDNSfalse; // Last char must be ')' + if (!mDNSIsDigit(name->c[l])) return mDNSfalse; // Preceeded by a digit + l--; + while (l > 2 && mDNSIsDigit(name->c[l])) l--; // Strip off digits + return (name->c[l] == '(' && name->c[l - 1] == ' '); + } + else + { + if (l < 2) return mDNSfalse; // Need at least "-2" + if (!mDNSIsDigit(name->c[l])) return mDNSfalse; // Last char must be a digit + l--; + while (l > 2 && mDNSIsDigit(name->c[l])) l--; // Strip off digits + return (name->c[l] == '-'); + } +} + +// removes an auto-generated suffix (appended on a name collision) from a label. caller is +// responsible for ensuring that the label does indeed contain a suffix. returns the number +// from the suffix that was removed. +mDNSexport mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText) +{ + mDNSu32 val = 0, multiplier = 1; + + // Chop closing parentheses from RichText suffix + if (RichText && name->c[0] >= 1 && name->c[name->c[0]] == ')') name->c[0]--; + + // Get any existing numerical suffix off the name + while (mDNSIsDigit(name->c[name->c[0]])) + { val += (name->c[name->c[0]] - '0') * multiplier; multiplier *= 10; name->c[0]--; } + + // Chop opening parentheses or dash from suffix + if (RichText) + { + if (name->c[0] >= 2 && name->c[name->c[0]] == '(' && name->c[name->c[0]-1] == ' ') name->c[0] -= 2; + } + else + { + if (name->c[0] >= 1 && name->c[name->c[0]] == '-') name->c[0] -= 1; + } + + return(val); +} + +// appends a numerical suffix to a label, with the number following a whitespace and enclosed +// in parentheses (rich text) or following two consecutive hyphens (RFC 1034 domain label). +mDNSexport void AppendLabelSuffix(domainlabel *const name, mDNSu32 val, const mDNSBool RichText) +{ + mDNSu32 divisor = 1, chars = 2; // Shortest possible RFC1034 name suffix is 2 characters ("-2") + if (RichText) chars = 4; // Shortest possible RichText suffix is 4 characters (" (2)") + + // Truncate trailing spaces from RichText names + if (RichText) while (name->c[name->c[0]] == ' ') name->c[0]--; + + while (divisor < 0xFFFFFFFFUL/10 && val >= divisor * 10) { divisor *= 10; chars++; } + + name->c[0] = (mDNSu8) TruncateUTF8ToLength(name->c+1, name->c[0], MAX_DOMAIN_LABEL - chars); + + if (RichText) { name->c[++name->c[0]] = ' '; name->c[++name->c[0]] = '('; } + else { name->c[++name->c[0]] = '-'; } + + while (divisor) + { + name->c[++name->c[0]] = (mDNSu8)('0' + val / divisor); + val %= divisor; + divisor /= 10; + } + + if (RichText) name->c[++name->c[0]] = ')'; +} + +mDNSexport void IncrementLabelSuffix(domainlabel *name, mDNSBool RichText) +{ + mDNSu32 val = 0; + + if (LabelContainsSuffix(name, RichText)) + val = RemoveLabelSuffix(name, RichText); + + // If no existing suffix, start by renaming "Foo" as "Foo (2)" or "Foo-2" as appropriate. + // If existing suffix in the range 2-9, increment it. + // If we've had ten conflicts already, there are probably too many hosts trying to use the same name, + // so add a random increment to improve the chances of finding an available name next time. + if (val == 0) val = 2; + else if (val < 10) val++; + else val += 1 + mDNSRandom(99); + + AppendLabelSuffix(name, val, RichText); +} + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - Resource Record Utility Functions +#endif + +// Set up a AuthRecord with sensible default values. +// These defaults may be overwritten with new values before mDNS_Register is called +mDNSexport void mDNS_SetupResourceRecord(AuthRecord *rr, RData *RDataStorage, mDNSInterfaceID InterfaceID, + mDNSu16 rrtype, mDNSu32 ttl, mDNSu8 RecordType, AuthRecType artype, mDNSRecordCallback Callback, void *Context) +{ + // + // LocalOnly auth record can be created with LocalOnly InterfaceID or a valid InterfaceID. + // Most of the applications normally create with LocalOnly InterfaceID and we store them as + // such, so that we can deliver the response to questions that specify LocalOnly InterfaceID. + // LocalOnly resource records can also be created with valid InterfaceID which happens today + // when we create LocalOnly records for /etc/hosts. + + if (InterfaceID == mDNSInterface_LocalOnly && artype != AuthRecordLocalOnly) + { + LogMsg("mDNS_SetupResourceRecord: ERROR!! Mismatch LocalOnly record InterfaceID %p called with artype %d", InterfaceID, artype); + return; + } + else if (InterfaceID == mDNSInterface_P2P && artype != AuthRecordP2P) + { + LogMsg("mDNS_SetupResourceRecord: ERROR!! Mismatch P2P record InterfaceID %p called with artype %d", InterfaceID, artype); + return; + } + else if (!InterfaceID && (artype == AuthRecordP2P || artype == AuthRecordLocalOnly)) + { + LogMsg("mDNS_SetupResourceRecord: ERROR!! Mismatch InterfaceAny record InterfaceID %p called with artype %d", InterfaceID, artype); + return; + } + + // Don't try to store a TTL bigger than we can represent in platform time units + if (ttl > 0x7FFFFFFFUL / mDNSPlatformOneSecond) + ttl = 0x7FFFFFFFUL / mDNSPlatformOneSecond; + else if (ttl == 0) // And Zero TTL is illegal + ttl = DefaultTTLforRRType(rrtype); + + // Field Group 1: The actual information pertaining to this resource record + rr->resrec.RecordType = RecordType; + rr->resrec.InterfaceID = InterfaceID; + rr->resrec.name = &rr->namestorage; + rr->resrec.rrtype = rrtype; + rr->resrec.rrclass = kDNSClass_IN; + rr->resrec.rroriginalttl = ttl; + rr->resrec.rDNSServer = mDNSNULL; + rr->resrec.AnonInfo = mDNSNULL; +// rr->resrec.rdlength = MUST set by client and/or in mDNS_Register_internal +// rr->resrec.rdestimate = set in mDNS_Register_internal +// rr->resrec.rdata = MUST be set by client + + if (RDataStorage) + rr->resrec.rdata = RDataStorage; + else + { + rr->resrec.rdata = &rr->rdatastorage; + rr->resrec.rdata->MaxRDLength = sizeof(RDataBody); + } + + // Field Group 2: Persistent metadata for Authoritative Records + rr->Additional1 = mDNSNULL; + rr->Additional2 = mDNSNULL; + rr->DependentOn = mDNSNULL; + rr->RRSet = mDNSNULL; + rr->RecordCallback = Callback; + rr->RecordContext = Context; + + rr->AutoTarget = Target_Manual; + rr->AllowRemoteQuery = mDNSfalse; + rr->ForceMCast = mDNSfalse; + + rr->WakeUp = zeroOwner; + rr->AddressProxy = zeroAddr; + rr->TimeRcvd = 0; + rr->TimeExpire = 0; + rr->ARType = artype; + rr->AuthFlags = 0; + + // Field Group 3: Transient state for Authoritative Records (set in mDNS_Register_internal) + // Field Group 4: Transient uDNS state for Authoritative Records (set in mDNS_Register_internal) + + // For now, until the uDNS code is fully integrated, it's helpful to zero the uDNS state fields here too, just in case + // (e.g. uDNS_RegisterService short-circuits the usual mDNS_Register_internal record registration calls, so a bunch + // of fields don't get set up properly. In particular, if we don't zero rr->QueuedRData then the uDNS code crashes.) + rr->state = regState_Zero; + rr->uselease = 0; + rr->expire = 0; + rr->Private = 0; + rr->updateid = zeroID; + rr->zone = rr->resrec.name; + rr->nta = mDNSNULL; + rr->tcp = mDNSNULL; + rr->OrigRData = 0; + rr->OrigRDLen = 0; + rr->InFlightRData = 0; + rr->InFlightRDLen = 0; + rr->QueuedRData = 0; + rr->QueuedRDLen = 0; + mDNSPlatformMemZero(&rr->NATinfo, sizeof(rr->NATinfo)); + rr->SRVChanged = mDNSfalse; + rr->mState = mergeState_Zero; + + rr->namestorage.c[0] = 0; // MUST be set by client before calling mDNS_Register() +} + +mDNSexport void mDNS_SetupQuestion(DNSQuestion *const q, const mDNSInterfaceID InterfaceID, const domainname *const name, + const mDNSu16 qtype, mDNSQuestionCallback *const callback, void *const context) +{ + q->InterfaceID = InterfaceID; + q->flags = 0; + q->Target = zeroAddr; + AssignDomainName(&q->qname, name); + q->qtype = qtype; + q->qclass = kDNSClass_IN; + q->LongLived = (qtype == kDNSType_PTR); + q->ExpectUnique = (qtype != kDNSType_PTR); + q->ForceMCast = mDNSfalse; + q->ReturnIntermed = mDNSfalse; + q->SuppressUnusable = mDNSfalse; + q->SearchListIndex = 0; + q->AppendSearchDomains = 0; + q->RetryWithSearchDomains = mDNSfalse; + q->TimeoutQuestion = 0; + q->WakeOnResolve = 0; + q->UseBackgroundTrafficClass = mDNSfalse; + q->ValidationRequired = 0; + q->ValidatingResponse = 0; + q->ProxyQuestion = 0; + q->qnameOrig = mDNSNULL; + q->AnonInfo = mDNSNULL; + q->pid = mDNSPlatformGetPID(); + q->DisallowPID = mDNSfalse; + q->ServiceID = -1; + q->QuestionCallback = callback; + q->QuestionContext = context; +} + +mDNSexport mDNSu32 RDataHashValue(const ResourceRecord *const rr) +{ + int len = rr->rdlength; + const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; + const mDNSu8 *ptr = rdb->data; + mDNSu32 sum = 0; + + switch(rr->rrtype) + { + case kDNSType_NS: + case kDNSType_MD: + case kDNSType_MF: + case kDNSType_CNAME: + case kDNSType_MB: + case kDNSType_MG: + case kDNSType_MR: + case kDNSType_PTR: + case kDNSType_NSAP_PTR: + case kDNSType_DNAME: return DomainNameHashValue(&rdb->name); + + case kDNSType_SOA: return rdb->soa.serial + + rdb->soa.refresh + + rdb->soa.retry + + rdb->soa.expire + + rdb->soa.min + + DomainNameHashValue(&rdb->soa.mname) + + DomainNameHashValue(&rdb->soa.rname); + + case kDNSType_MX: + case kDNSType_AFSDB: + case kDNSType_RT: + case kDNSType_KX: return DomainNameHashValue(&rdb->mx.exchange); + + case kDNSType_MINFO: + case kDNSType_RP: return DomainNameHashValue(&rdb->rp.mbox) + DomainNameHashValue(&rdb->rp.txt); + + case kDNSType_PX: return DomainNameHashValue(&rdb->px.map822) + DomainNameHashValue(&rdb->px.mapx400); + + case kDNSType_SRV: return DomainNameHashValue(&rdb->srv.target); + + case kDNSType_OPT: return 0; // OPT is a pseudo-RR container structure; makes no sense to compare + + case kDNSType_NSEC: { + int dlen; + dlen = DomainNameLength((domainname *)rdb->data); + sum = DomainNameHashValue((domainname *)rdb->data); + ptr += dlen; + len -= dlen; + /* FALLTHROUGH */ + } + + default: + { + int i; + for (i=0; i+1 < len; i+=2) + { + sum += (((mDNSu32)(ptr[i])) << 8) | ptr[i+1]; + sum = (sum<<3) | (sum>>29); + } + if (i < len) + { + sum += ((mDNSu32)(ptr[i])) << 8; + } + return(sum); + } + } +} + +// r1 has to be a full ResourceRecord including rrtype and rdlength +// r2 is just a bare RDataBody, which MUST be the same rrtype and rdlength as r1 +mDNSexport mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2, DomainNameComparisonFn *samename) +{ + const RDataBody2 *const b1 = (RDataBody2 *)r1->rdata->u.data; + const RDataBody2 *const b2 = (RDataBody2 *)r2; + switch(r1->rrtype) + { + case kDNSType_NS: + case kDNSType_MD: + case kDNSType_MF: + case kDNSType_CNAME: + case kDNSType_MB: + case kDNSType_MG: + case kDNSType_MR: + case kDNSType_PTR: + case kDNSType_NSAP_PTR: + case kDNSType_DNAME: return(SameDomainName(&b1->name, &b2->name)); + + case kDNSType_SOA: return (mDNSBool)( b1->soa.serial == b2->soa.serial && + b1->soa.refresh == b2->soa.refresh && + b1->soa.retry == b2->soa.retry && + b1->soa.expire == b2->soa.expire && + b1->soa.min == b2->soa.min && + samename(&b1->soa.mname, &b2->soa.mname) && + samename(&b1->soa.rname, &b2->soa.rname)); + + case kDNSType_MX: + case kDNSType_AFSDB: + case kDNSType_RT: + case kDNSType_KX: return (mDNSBool)( b1->mx.preference == b2->mx.preference && + samename(&b1->mx.exchange, &b2->mx.exchange)); + + case kDNSType_MINFO: + case kDNSType_RP: return (mDNSBool)( samename(&b1->rp.mbox, &b2->rp.mbox) && + samename(&b1->rp.txt, &b2->rp.txt)); + + case kDNSType_PX: return (mDNSBool)( b1->px.preference == b2->px.preference && + samename(&b1->px.map822, &b2->px.map822) && + samename(&b1->px.mapx400, &b2->px.mapx400)); + + case kDNSType_SRV: return (mDNSBool)( b1->srv.priority == b2->srv.priority && + b1->srv.weight == b2->srv.weight && + mDNSSameIPPort(b1->srv.port, b2->srv.port) && + samename(&b1->srv.target, &b2->srv.target)); + + case kDNSType_OPT: return mDNSfalse; // OPT is a pseudo-RR container structure; makes no sense to compare + case kDNSType_NSEC: { + // If the "nxt" name changes in case, we want to delete the old + // and store just the new one. If the caller passes in SameDomainCS for "samename", + // we would return "false" when the only change between the two rdata is the case + // change in "nxt". + // + // Note: rdlength of both the RData are same (ensured by the caller) and hence we can + // use just r1->rdlength below + + int dlen1 = DomainNameLength((domainname *)b1->data); + int dlen2 = DomainNameLength((domainname *)b2->data); + return (mDNSBool)(dlen1 == dlen2 && + samename((domainname *)b1->data, (domainname *)b2->data) && + mDNSPlatformMemSame(b1->data + dlen1, b2->data + dlen2, r1->rdlength - dlen1)); + } + + default: return(mDNSPlatformMemSame(b1->data, b2->data, r1->rdlength)); + } +} + +mDNSexport mDNSBool BitmapTypeCheck(mDNSu8 *bmap, int bitmaplen, mDNSu16 type) +{ + int win, wlen; + int wintype; + + // The window that this type belongs to. NSEC has 256 windows that + // comprises of 256 types. + wintype = type >> 8; + + while (bitmaplen > 0) + { + if (bitmaplen < 3) + { + LogInfo("BitmapTypeCheck: malformed nsec, bitmaplen %d short", bitmaplen); + return mDNSfalse; + } + + win = *bmap++; + wlen = *bmap++; + bitmaplen -= 2; + if (bitmaplen < wlen || wlen < 1 || wlen > 32) + { + LogInfo("BitmapTypeCheck: malformed nsec, bitmaplen %d wlen %d, win %d", bitmaplen, wlen, win); + return mDNSfalse; + } + if (win < 0 || win >= 256) + { + LogInfo("BitmapTypeCheck: malformed nsec, wlen %d", wlen); + return mDNSfalse; + } + if (win == wintype) + { + // First byte in the window serves 0 to 7, the next one serves 8 to 15 and so on. + // Calculate the right byte offset first. + int boff = (type & 0xff ) >> 3; + if (wlen <= boff) + return mDNSfalse; + // The last three bits values 0 to 7 corresponds to bit positions + // within the byte. + return (bmap[boff] & (0x80 >> (type & 7))); + } + else + { + // If the windows are ordered, then we could check to see + // if wintype > win and then return early. + bmap += wlen; + bitmaplen -= wlen; + } + } + return mDNSfalse; +} + +// Don't call this function if the resource record is not NSEC. It will return false +// which means that the type does not exist. +mDNSexport mDNSBool RRAssertsExistence(const ResourceRecord *const rr, mDNSu16 type) +{ + const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; + mDNSu8 *nsec = (mDNSu8 *)rdb->data; + int len, bitmaplen; + mDNSu8 *bmap; + + if (rr->rrtype != kDNSType_NSEC) return mDNSfalse; + + len = DomainNameLength((domainname *)nsec); + + bitmaplen = rr->rdlength - len; + bmap = nsec + len; + return (BitmapTypeCheck(bmap, bitmaplen, type)); +} + +// Don't call this function if the resource record is not NSEC. It will return false +// which means that the type exists. +mDNSexport mDNSBool RRAssertsNonexistence(const ResourceRecord *const rr, mDNSu16 type) +{ + if (rr->rrtype != kDNSType_NSEC) return mDNSfalse; + + return !RRAssertsExistence(rr, type); +} + +// Checks whether the RRSIG or NSEC record answers the question "q". +mDNSlocal mDNSBool DNSSECRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q, mDNSBool *checkType) +{ + *checkType = mDNStrue; + + // This function is called for all questions and as long as the type matches, + // return true. For the types (RRSIG and NSEC) that are specifically checked in + // this function, returning true still holds good. + if (q->qtype == rr->rrtype) + return mDNStrue; + + // For DS and DNSKEY questions, the types should match i.e., don't answer using CNAME + // records as it answers any question type. + // + // - DS record comes from the parent zone where CNAME record cannot coexist and hence + // cannot possibly answer it. + // + // - For DNSKEY, one could potentially follow CNAME but there could be a DNSKEY at + // the "qname" itself. To keep it simple, we don't follow CNAME. + + if ((q->qtype == kDNSType_DS || q->qtype == kDNSType_DNSKEY) && (q->qtype != rr->rrtype)) + { + debugf("DNSSECRecordAnswersQuestion: %d type resource record matched question %##s (%s), ignoring", rr->rrtype, + q->qname.c, DNSTypeName(q->qtype)); + return mDNSfalse; + } + + // If we are validating a response using DNSSEC, we might already have the records + // for the "q->qtype" in the cache but we issued a query with DO bit set + // to get the RRSIGs e.g., if you have two questions one of which does not require + // DNSSEC validation. When the RRSIG is added to the cache, we need to deliver + // the response to the question. The RRSIG type won't match the q->qtype and hence + // we need to bypass the check in that case. + if (rr->rrtype == kDNSType_RRSIG && q->ValidatingResponse) + { + const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; + rdataRRSig *rrsig = (rdataRRSig *)rdb->data; + mDNSu16 typeCovered = swap16(rrsig->typeCovered); + debugf("DNSSECRecordAnswersQuestion: Matching RRSIG typeCovered %s", DNSTypeName(typeCovered)); + if (typeCovered != kDNSType_CNAME && typeCovered != q->qtype) + { + debugf("DNSSECRecordAnswersQuestion: RRSIG did not match question %##s (%s)", q->qname.c, + DNSTypeName(q->qtype)); + return mDNSfalse; + } + LogInfo("DNSSECRecordAnswersQuestion: RRSIG matched question %##s (%s)", q->qname.c, + DNSTypeName(q->qtype)); + *checkType = mDNSfalse; + return mDNStrue; + } + // If the NSEC record asserts the non-existence of a name looked up by the question, we would + // typically answer that e.g., the bitmap asserts that q->qtype does not exist. If we have + // to prove the non-existence as required by ValidatingResponse and ValidationRequired question, + // then we should not answer that as it may not be the right one always. We may need more than + // one NSEC to prove the non-existence. + if (rr->rrtype == kDNSType_NSEC && DNSSECQuestion(q)) + { + debugf("DNSSECRecordAnswersQuestion: Question %##s (%s) matched record %##s (NSEC)", q->qname.c, + DNSTypeName(q->qtype), rr->name->c); + return mDNSfalse; + } + return mDNStrue; +} + +// ResourceRecordAnswersQuestion returns mDNStrue if the given resource record is a valid answer to the given question. +// SameNameRecordAnswersQuestion is the same, except it skips the expensive SameDomainName() call. +// SameDomainName() is generally cheap when the names don't match, but expensive when they do match, +// because it has to check all the way to the end of the names to be sure. +// In cases where we know in advance that the names match it's especially advantageous to skip the +// SameDomainName() call because that's precisely the time when it's most expensive and least useful. + +mDNSexport mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) +{ + mDNSBool checkType = mDNStrue; + + // LocalOnly/P2P questions can be answered with AuthRecordAny in this function. LocalOnly/P2P records + // are handled in LocalOnlyRecordAnswersQuestion + if ((rr->InterfaceID == mDNSInterface_LocalOnly) || (rr->InterfaceID == mDNSInterface_P2P)) + { + LogMsg("SameNameRecordAnswersQuestion: ERROR!! called with LocalOnly ResourceRecord %p, Question %p", rr->InterfaceID, q->InterfaceID); + return mDNSfalse; + } + if (QuerySuppressed(q)) + return mDNSfalse; + + if (rr->InterfaceID && + q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && + rr->InterfaceID != q->InterfaceID) return(mDNSfalse); + + // Resource record received via unicast, the resolver group ID should match ? + if (!rr->InterfaceID) + { + mDNSu16 idr = (rr->rDNSServer ? rr->rDNSServer->resGroupID : 0); + mDNSu16 idq = (q->qDNSServer ? q->qDNSServer->resGroupID : 0); + if (idr != idq) return(mDNSfalse); + if (!DNSSECRecordAnswersQuestion(rr, q, &checkType)) return mDNSfalse; + } + + // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question + if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); + + // CNAME answers question of any type and a negative cache record should not prevent us from querying other + // valid types at the same name. + if (rr->rrtype == kDNSType_CNAME && rr->RecordType == kDNSRecordTypePacketNegative && rr->rrtype != q->qtype) + return mDNSfalse; + + // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. + if (checkType && !RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); + if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); + +#if APPLE_OSX_mDNSResponder + if (!mDNSPlatformValidRecordForQuestion(rr, q)) + return mDNSfalse; +#endif // APPLE_OSX_mDNSResponder + + if (!AnonInfoAnswersQuestion(rr, q)) + return mDNSfalse; + + return(mDNStrue); +} + +mDNSexport mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) +{ + if (!SameNameRecordAnswersQuestion(rr, q)) + return mDNSfalse; + + return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); +} + +// We have a separate function to handle LocalOnly AuthRecords because they can be created with +// a valid InterfaceID (e.g., scoped /etc/hosts) and can be used to answer unicast questions unlike +// multicast resource records (which has a valid InterfaceID) which can't be used to answer +// unicast questions. ResourceRecordAnswersQuestion/SameNameRecordAnswersQuestion can't tell whether +// a resource record is multicast or LocalOnly by just looking at the ResourceRecord because +// LocalOnly records are truly identified by ARType in the AuthRecord. As P2P and LocalOnly record +// are kept in the same hash table, we use the same function to make it easy for the callers when +// they walk the hash table to answer LocalOnly/P2P questions +// +mDNSexport mDNSBool LocalOnlyRecordAnswersQuestion(AuthRecord *const ar, const DNSQuestion *const q) +{ + ResourceRecord *rr = &ar->resrec; + + // mDNSInterface_Any questions can be answered with LocalOnly/P2P records in this function. AuthRecord_Any + // records are handled in ResourceRecordAnswersQuestion/SameNameRecordAnswersQuestion + if (RRAny(ar)) + { + LogMsg("LocalOnlyRecordAnswersQuestion: ERROR!! called with regular AuthRecordAny %##s", rr->name->c); + return mDNSfalse; + } + + // Questions with mDNSInterface_LocalOnly InterfaceID should be answered with all resource records that are + // *local* to the machine. These include resource records that have InterfaceID set to mDNSInterface_LocalOnly, + // mDNSInterface_Any and any other real InterfaceID. Hence, LocalOnly questions should not be checked against + // the InterfaceID in the resource record. + // + // mDNSInterface_Unicast does not indicate any scope and hence treat them like mDNSInterface_Any. + + if (rr->InterfaceID && + q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && q->InterfaceID != mDNSInterface_Unicast && + rr->InterfaceID != q->InterfaceID) return(mDNSfalse); + + // Entries in /etc/hosts are added as LocalOnly resource records. The LocalOnly resource records + // may have a scope e.g., fe80::1%en0. The question may be scoped or not: the InterfaceID may be set + // to mDNSInterface_Any, mDNSInterface_LocalOnly or a real InterfaceID (scoped). + // + // 1) Question: Any, LocalOnly Record: no scope. This question should be answered with this record. + // + // 2) Question: Any, LocalOnly Record: scoped. This question should be answered with the record because + // traditionally applications never specify scope e.g., getaddrinfo, but need to be able + // to get to /etc/hosts entries. + // + // 3) Question: Scoped (LocalOnly or InterfaceID), LocalOnly Record: no scope. This is the inverse of (2). + // If we register a LocalOnly record, we need to answer a LocalOnly question. If the /etc/hosts has a + // non scoped entry, it may not make sense to answer a scoped question. But we can't tell these two + // cases apart. As we currently answer LocalOnly question with LocalOnly record, we continue to do so. + // + // 4) Question: Scoped (LocalOnly or InterfaceID), LocalOnly Record: scoped. LocalOnly questions should be + // answered with any resource record where as if it has a valid InterfaceID, the scope should match. + // + // (1) and (2) is bypassed because we check for a non-NULL InterfaceID above. For (3), the InterfaceID is NULL + // and hence bypassed above. For (4) we bypassed LocalOnly questions and checked the scope of the record + // against the question. + // + // For P2P, InterfaceIDs of the question and the record should match. + + // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question. + // LocalOnly authoritative answers are exempt. LocalOnly authoritative answers are used for /etc/host entries. + // We don't want a local process to be able to create a fake LocalOnly address record for "www.bigbank.com" which would then + // cause other applications (e.g. Safari) to connect to the wrong address. The rpc to register records filters out records + // with names that don't end in local and have mDNSInterface_LocalOnly set. + // + // Note: The check is bypassed for LocalOnly and for P2P it is not needed as only .local records are registered and for + // a question to match its names, it also has to end in .local and that question can't be a unicast question (See + // Question_uDNS macro and its usage). As P2P does not enforce .local only registrations we still make this check + // and also makes it future proof. + + if (ar->ARType != AuthRecordLocalOnly && rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); + + // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. + if (!RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); + if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); + + if (!AnonInfoAnswersQuestion(rr, q)) + return mDNSfalse; + + return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); +} + +mDNSexport mDNSBool AnyTypeRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) +{ + // LocalOnly/P2P questions can be answered with AuthRecordAny in this function. LocalOnly/P2P records + // are handled in LocalOnlyRecordAnswersQuestion + if ((rr->InterfaceID == mDNSInterface_LocalOnly) || (rr->InterfaceID == mDNSInterface_P2P)) + { + LogMsg("AnyTypeRecordAnswersQuestion: ERROR!! called with LocalOnly ResourceRecord %p, Question %p", rr->InterfaceID, q->InterfaceID); + return mDNSfalse; + } + if (rr->InterfaceID && + q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && + rr->InterfaceID != q->InterfaceID) return(mDNSfalse); + + // Resource record received via unicast, the resolver group ID should match ? + // Note that Auth Records are normally setup with NULL InterfaceID and + // both the DNSServers are assumed to be NULL in that case + if (!rr->InterfaceID) + { + mDNSu16 idr = (rr->rDNSServer ? rr->rDNSServer->resGroupID : 0); + mDNSu16 idq = (q->qDNSServer ? q->qDNSServer->resGroupID : 0); + if (idr != idq) return(mDNSfalse); + } + + // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question + if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); + + if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); + + if (!AnonInfoAnswersQuestion(rr, q)) + return mDNSfalse; + + return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); +} + +// This is called with both unicast resource record and multicast resource record. The question that +// received the unicast response could be the regular unicast response from a DNS server or a response +// to a mDNS QU query. The main reason we need this function is that we can't compare DNSServers between the +// question and the resource record because the resource record is not completely initialized in +// mDNSCoreReceiveResponse when this function is called. +mDNSexport mDNSBool ResourceRecordAnswersUnicastResponse(const ResourceRecord *const rr, const DNSQuestion *const q) +{ + mDNSBool checkType = mDNStrue; + + if (QuerySuppressed(q)) + return mDNSfalse; + + // For resource records created using multicast, the InterfaceIDs have to match + if (rr->InterfaceID && + q->InterfaceID && rr->InterfaceID != q->InterfaceID) return(mDNSfalse); + + // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question. + if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); + + if (!DNSSECRecordAnswersQuestion(rr, q, &checkType)) return mDNSfalse; + + // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. + if (checkType && !RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); + + if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); + + return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); +} + +mDNSexport mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate) +{ + const RDataBody2 *const rd = (RDataBody2 *)rr->rdata->u.data; + const domainname *const name = estimate ? rr->name : mDNSNULL; + if (rr->rrclass == kDNSQClass_ANY) return(rr->rdlength); // Used in update packets to mean "Delete An RRset" (RFC 2136) + else switch (rr->rrtype) + { + case kDNSType_A: return(sizeof(rd->ipv4)); + + case kDNSType_NS: + case kDNSType_CNAME: + case kDNSType_PTR: + case kDNSType_DNAME: return(CompressedDomainNameLength(&rd->name, name)); + + case kDNSType_SOA: return (mDNSu16)(CompressedDomainNameLength(&rd->soa.mname, name) + + CompressedDomainNameLength(&rd->soa.rname, name) + + 5 * sizeof(mDNSOpaque32)); + + case kDNSType_NULL: + case kDNSType_TSIG: + case kDNSType_TXT: + case kDNSType_X25: + case kDNSType_ISDN: + case kDNSType_LOC: + case kDNSType_DHCID: return(rr->rdlength); // Not self-describing, so have to just trust rdlength + + case kDNSType_HINFO: return (mDNSu16)(2 + (int)rd->data[0] + (int)rd->data[1 + (int)rd->data[0]]); + + case kDNSType_MX: + case kDNSType_AFSDB: + case kDNSType_RT: + case kDNSType_KX: return (mDNSu16)(2 + CompressedDomainNameLength(&rd->mx.exchange, name)); + + case kDNSType_RP: return (mDNSu16)(CompressedDomainNameLength(&rd->rp.mbox, name) + + CompressedDomainNameLength(&rd->rp.txt, name)); + + case kDNSType_PX: return (mDNSu16)(2 + CompressedDomainNameLength(&rd->px.map822, name) + + CompressedDomainNameLength(&rd->px.mapx400, name)); + + case kDNSType_AAAA: return(sizeof(rd->ipv6)); + + case kDNSType_SRV: return (mDNSu16)(6 + CompressedDomainNameLength(&rd->srv.target, name)); + + case kDNSType_OPT: return(rr->rdlength); + + case kDNSType_NSEC: { + domainname *next = (domainname *)rd->data; + int dlen = DomainNameLength(next); + // + if (UNICAST_NSEC(rr)) + return (mDNSu16)(CompressedDomainNameLength(next, name) + rr->rdlength - dlen); + else + return (mDNSu16)((estimate ? 2 : dlen) + rr->rdlength - dlen); + } + + default: debugf("Warning! Don't know how to get length of resource type %d", rr->rrtype); + return(rr->rdlength); + } +} + +// When a local client registers (or updates) a record, we use this routine to do some simple validation checks +// to help reduce the risk of bogus malformed data on the network +mDNSexport mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd) +{ + mDNSu16 len; + + switch(rrtype) + { + case kDNSType_A: return(rdlength == sizeof(mDNSv4Addr)); + + case kDNSType_NS: // Same as PTR + case kDNSType_MD: // Same as PTR + case kDNSType_MF: // Same as PTR + case kDNSType_CNAME: // Same as PTR + //case kDNSType_SOA not checked + case kDNSType_MB: // Same as PTR + case kDNSType_MG: // Same as PTR + case kDNSType_MR: // Same as PTR + //case kDNSType_NULL not checked (no specified format, so always valid) + //case kDNSType_WKS not checked + case kDNSType_PTR: len = DomainNameLengthLimit(&rd->u.name, rd->u.data + rdlength); + return(len <= MAX_DOMAIN_NAME && rdlength == len); + + case kDNSType_HINFO: // Same as TXT (roughly) + case kDNSType_MINFO: // Same as TXT (roughly) + case kDNSType_TXT: if (!rdlength) return(mDNSfalse); // TXT record has to be at least one byte (RFC 1035) + { + const mDNSu8 *ptr = rd->u.txt.c; + const mDNSu8 *end = rd->u.txt.c + rdlength; + while (ptr < end) ptr += 1 + ptr[0]; + return (ptr == end); + } + + case kDNSType_AAAA: return(rdlength == sizeof(mDNSv6Addr)); + + case kDNSType_MX: // Must be at least two-byte preference, plus domainname + // Call to DomainNameLengthLimit() implicitly enforces both requirements for us + len = DomainNameLengthLimit(&rd->u.mx.exchange, rd->u.data + rdlength); + return(len <= MAX_DOMAIN_NAME && rdlength == 2+len); + + case kDNSType_SRV: // Must be at least priority+weight+port, plus domainname + // Call to DomainNameLengthLimit() implicitly enforces both requirements for us + len = DomainNameLengthLimit(&rd->u.srv.target, rd->u.data + rdlength); + return(len <= MAX_DOMAIN_NAME && rdlength == 6+len); + + //case kDNSType_NSEC not checked + + default: return(mDNStrue); // Allow all other types without checking + } +} + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - DNS Message Creation Functions +#endif + +mDNSexport void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags) +{ + h->id = id; + h->flags = flags; + h->numQuestions = 0; + h->numAnswers = 0; + h->numAuthorities = 0; + h->numAdditionals = 0; +} + +mDNSexport const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname) +{ + const mDNSu8 *result = end - *domname - 1; + + if (*domname == 0) return(mDNSNULL); // There's no point trying to match just the root label + + // This loop examines each possible starting position in packet, starting end of the packet and working backwards + while (result >= base) + { + // If the length byte and first character of the label match, then check further to see + // if this location in the packet will yield a useful name compression pointer. + if (result[0] == domname[0] && result[1] == domname[1]) + { + const mDNSu8 *name = domname; + const mDNSu8 *targ = result; + while (targ + *name < end) + { + // First see if this label matches + int i; + const mDNSu8 *pointertarget; + for (i=0; i <= *name; i++) if (targ[i] != name[i]) break; + if (i <= *name) break; // If label did not match, bail out + targ += 1 + *name; // Else, did match, so advance target pointer + name += 1 + *name; // and proceed to check next label + if (*name == 0 && *targ == 0) return(result); // If no more labels, we found a match! + if (*name == 0) break; // If no more labels to match, we failed, so bail out + + // The label matched, so now follow the pointer (if appropriate) and then see if the next label matches + if (targ[0] < 0x40) continue; // If length value, continue to check next label + if (targ[0] < 0xC0) break; // If 40-BF, not valid + if (targ+1 >= end) break; // Second byte not present! + pointertarget = base + (((mDNSu16)(targ[0] & 0x3F)) << 8) + targ[1]; + if (targ < pointertarget) break; // Pointertarget must point *backwards* in the packet + if (pointertarget[0] >= 0x40) break; // Pointertarget must point to a valid length byte + targ = pointertarget; + } + } + result--; // We failed to match at this search position, so back up the tentative result pointer and try again + } + return(mDNSNULL); +} + +// Put a string of dot-separated labels as length-prefixed labels +// domainname is a fully-qualified name (i.e. assumed to be ending in a dot, even if it doesn't) +// msg points to the message we're building (pass mDNSNULL if we don't want to use compression pointers) +// end points to the end of the message so far +// ptr points to where we want to put the name +// limit points to one byte past the end of the buffer that we must not overrun +// domainname is the name to put +mDNSexport mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, + mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name) +{ + const mDNSu8 *const base = (const mDNSu8 *)msg; + const mDNSu8 * np = name->c; + const mDNSu8 *const max = name->c + MAX_DOMAIN_NAME; // Maximum that's valid + const mDNSu8 * pointer = mDNSNULL; + const mDNSu8 *const searchlimit = ptr; + + if (!ptr) { LogMsg("putDomainNameAsLabels %##s ptr is null", name->c); return(mDNSNULL); } + + if (!*np) // If just writing one-byte root label, make sure we have space for that + { + if (ptr >= limit) return(mDNSNULL); + } + else // else, loop through writing labels and/or a compression offset + { + do { + if (*np > MAX_DOMAIN_LABEL) + { LogMsg("Malformed domain name %##s (label more than 63 bytes)", name->c); return(mDNSNULL); } + + // This check correctly allows for the final trailing root label: + // e.g. + // Suppose our domain name is exactly 256 bytes long, including the final trailing root label. + // Suppose np is now at name->c[249], and we're about to write our last non-null label ("local"). + // We know that max will be at name->c[256] + // That means that np + 1 + 5 == max - 1, so we (just) pass the "if" test below, write our + // six bytes, then exit the loop, write the final terminating root label, and the domain + // name we've written is exactly 256 bytes long, exactly at the correct legal limit. + // If the name is one byte longer, then we fail the "if" test below, and correctly bail out. + if (np + 1 + *np >= max) + { LogMsg("Malformed domain name %##s (more than 256 bytes)", name->c); return(mDNSNULL); } + + if (base) pointer = FindCompressionPointer(base, searchlimit, np); + if (pointer) // Use a compression pointer if we can + { + const mDNSu16 offset = (mDNSu16)(pointer - base); + if (ptr+2 > limit) return(mDNSNULL); // If we don't have two bytes of space left, give up + *ptr++ = (mDNSu8)(0xC0 | (offset >> 8)); + *ptr++ = (mDNSu8)( offset & 0xFF); + return(ptr); + } + else // Else copy one label and try again + { + int i; + mDNSu8 len = *np++; + // If we don't at least have enough space for this label *plus* a terminating zero on the end, give up + if (ptr + 1 + len >= limit) return(mDNSNULL); + *ptr++ = len; + for (i=0; i<len; i++) *ptr++ = *np++; + } + } while (*np); // While we've got characters remaining in the name, continue + } + + *ptr++ = 0; // Put the final root label + return(ptr); +} + +mDNSlocal mDNSu8 *putVal16(mDNSu8 *ptr, mDNSu16 val) +{ + ptr[0] = (mDNSu8)((val >> 8 ) & 0xFF); + ptr[1] = (mDNSu8)((val ) & 0xFF); + return ptr + sizeof(mDNSOpaque16); +} + +mDNSlocal mDNSu8 *putVal32(mDNSu8 *ptr, mDNSu32 val) +{ + ptr[0] = (mDNSu8)((val >> 24) & 0xFF); + ptr[1] = (mDNSu8)((val >> 16) & 0xFF); + ptr[2] = (mDNSu8)((val >> 8) & 0xFF); + ptr[3] = (mDNSu8)((val ) & 0xFF); + return ptr + sizeof(mDNSu32); +} + +// Copy the RDATA information. The actual in memory storage for the data might be bigger than what the rdlength +// says. Hence, the only way to copy out the data from a resource record is to use putRData. +// msg points to the message we're building (pass mDNSNULL for "msg" if we don't want to use compression pointers) +mDNSexport mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr) +{ + const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; + switch (rr->rrtype) + { + case kDNSType_A: if (rr->rdlength != 4) + { debugf("putRData: Illegal length %d for kDNSType_A", rr->rdlength); return(mDNSNULL); } + if (ptr + 4 > limit) return(mDNSNULL); + *ptr++ = rdb->ipv4.b[0]; + *ptr++ = rdb->ipv4.b[1]; + *ptr++ = rdb->ipv4.b[2]; + *ptr++ = rdb->ipv4.b[3]; + return(ptr); + + case kDNSType_NS: + case kDNSType_CNAME: + case kDNSType_PTR: + case kDNSType_DNAME: return(putDomainNameAsLabels(msg, ptr, limit, &rdb->name)); + + case kDNSType_SOA: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.mname); + if (!ptr) return(mDNSNULL); + ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.rname); + if (!ptr || ptr + 20 > limit) return(mDNSNULL); + ptr = putVal32(ptr, rdb->soa.serial); + ptr = putVal32(ptr, rdb->soa.refresh); + ptr = putVal32(ptr, rdb->soa.retry); + ptr = putVal32(ptr, rdb->soa.expire); + ptr = putVal32(ptr, rdb->soa.min); + return(ptr); + + case kDNSType_NULL: + case kDNSType_HINFO: + case kDNSType_TSIG: + case kDNSType_TXT: + case kDNSType_X25: + case kDNSType_ISDN: + case kDNSType_LOC: + case kDNSType_DHCID: if (ptr + rr->rdlength > limit) return(mDNSNULL); + mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); + return(ptr + rr->rdlength); + + case kDNSType_MX: + case kDNSType_AFSDB: + case kDNSType_RT: + case kDNSType_KX: if (ptr + 3 > limit) return(mDNSNULL); + ptr = putVal16(ptr, rdb->mx.preference); + return(putDomainNameAsLabels(msg, ptr, limit, &rdb->mx.exchange)); + + case kDNSType_RP: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.mbox); + if (!ptr) return(mDNSNULL); + ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.txt); + return(ptr); + + case kDNSType_PX: if (ptr + 5 > limit) return(mDNSNULL); + ptr = putVal16(ptr, rdb->px.preference); + ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.map822); + if (!ptr) return(mDNSNULL); + ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.mapx400); + return(ptr); + + case kDNSType_AAAA: if (rr->rdlength != sizeof(rdb->ipv6)) + { debugf("putRData: Illegal length %d for kDNSType_AAAA", rr->rdlength); return(mDNSNULL); } + if (ptr + sizeof(rdb->ipv6) > limit) return(mDNSNULL); + mDNSPlatformMemCopy(ptr, &rdb->ipv6, sizeof(rdb->ipv6)); + return(ptr + sizeof(rdb->ipv6)); + + case kDNSType_SRV: if (ptr + 7 > limit) return(mDNSNULL); + *ptr++ = (mDNSu8)(rdb->srv.priority >> 8); + *ptr++ = (mDNSu8)(rdb->srv.priority & 0xFF); + *ptr++ = (mDNSu8)(rdb->srv.weight >> 8); + *ptr++ = (mDNSu8)(rdb->srv.weight & 0xFF); + *ptr++ = rdb->srv.port.b[0]; + *ptr++ = rdb->srv.port.b[1]; + return(putDomainNameAsLabels(msg, ptr, limit, &rdb->srv.target)); + + case kDNSType_OPT: { + int len = 0; + const rdataOPT *opt; + const rdataOPT *const end = (const rdataOPT *)&rr->rdata->u.data[rr->rdlength]; + for (opt = &rr->rdata->u.opt[0]; opt < end; opt++) + len += DNSOpt_Data_Space(opt); + if (ptr + len > limit) + { + LogMsg("ERROR: putOptRData - out of space"); + return mDNSNULL; + } + for (opt = &rr->rdata->u.opt[0]; opt < end; opt++) + { + const int space = DNSOpt_Data_Space(opt); + ptr = putVal16(ptr, opt->opt); + ptr = putVal16(ptr, (mDNSu16)space - 4); + switch (opt->opt) + { + case kDNSOpt_LLQ: + ptr = putVal16(ptr, opt->u.llq.vers); + ptr = putVal16(ptr, opt->u.llq.llqOp); + ptr = putVal16(ptr, opt->u.llq.err); + mDNSPlatformMemCopy(ptr, opt->u.llq.id.b, 8); // 8-byte id + ptr += 8; + ptr = putVal32(ptr, opt->u.llq.llqlease); + break; + case kDNSOpt_Lease: + ptr = putVal32(ptr, opt->u.updatelease); + break; + case kDNSOpt_Owner: + *ptr++ = opt->u.owner.vers; + *ptr++ = opt->u.owner.seq; + mDNSPlatformMemCopy(ptr, opt->u.owner.HMAC.b, 6); // 6-byte Host identifier + ptr += 6; + if (space >= DNSOpt_OwnerData_ID_Wake_Space) + { + mDNSPlatformMemCopy(ptr, opt->u.owner.IMAC.b, 6); // 6-byte interface MAC + ptr += 6; + if (space > DNSOpt_OwnerData_ID_Wake_Space) + { + mDNSPlatformMemCopy(ptr, opt->u.owner.password.b, space - DNSOpt_OwnerData_ID_Wake_Space); + ptr += space - DNSOpt_OwnerData_ID_Wake_Space; + } + } + break; + case kDNSOpt_Trace: + *ptr++ = opt->u.tracer.platf; + ptr = putVal32(ptr, opt->u.tracer.mDNSv); + break; + } + } + return ptr; + } + + case kDNSType_NSEC: { + // For NSEC records, rdlength represents the exact number of bytes + // of in memory storage. + int len = rr->rdlength; + mDNSu8 *nsec = (mDNSu8 *)rdb->data; + domainname *name = (domainname *)nsec; + int dlen; + + dlen = DomainNameLength(name); + len -= dlen; + nsec += dlen; + // This function is called when we are sending a NSEC record as part of mDNS, + // or to copy the data to any other buffer needed which could be a mDNS or uDNS + // NSEC record. The only time compression is used that when we are sending it + // in mDNS (indicated by non-NULL "msg") and hence we handle mDNS case + // separately. + if (!UNICAST_NSEC(rr)) + { + mDNSu8 *save = ptr; + int i, j, wlen; + wlen = *(nsec + 1); + nsec += 2; // Skip the window number and len + len -= 2; + + // For our simplified use of NSEC synthetic records: + // + // nextname is always the record's own name, + // the block number is always 0, + // the count byte is a value in the range 1-32, + // followed by the 1-32 data bytes + // + // Note: When we send the NSEC record in mDNS, the window size is set to 32. + // We need to find out what the last non-NULL byte is. If we are copying out + // from an RDATA, we have the right length. As we need to handle both the case, + // we loop to find the right value instead of blindly using len to copy. + + for (i=wlen; i>0; i--) if (nsec[i-1]) break; + + ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name); + if (!ptr) { LogInfo("putRData: Can't put name, Length %d, record %##s", limit - save, rr->name->c); return(mDNSNULL); } + if (i) // Only put a block if at least one type exists for this name + { + if (ptr + 2 + i > limit) { LogInfo("putRData: Can't put window, Length %d, i %d, record %##s", limit - ptr, i, rr->name->c); return(mDNSNULL); } + *ptr++ = 0; + *ptr++ = (mDNSu8)i; + for (j=0; j<i; j++) *ptr++ = nsec[j]; + } + return ptr; + } + else + { + int win, wlen; + + // Sanity check whether the bitmap is good + while (len) + { + if (len < 3) + { LogMsg("putRData: invalid length %d", len); return mDNSNULL; } + + win = *nsec++; + wlen = *nsec++; + len -= 2; + if (len < wlen || wlen < 1 || wlen > 32) + { LogMsg("putRData: invalid window length %d", wlen); return mDNSNULL; } + if (win < 0 || win >= 256) + { LogMsg("putRData: invalid window %d", win); return mDNSNULL; } + + nsec += wlen; + len -= wlen; + } + if (ptr + rr->rdlength > limit) { LogMsg("putRData: NSEC rdlength beyond limit %##s (%s), ptr %p, rdlength %d, limit %p", rr->name->c, DNSTypeName(rr->rrtype), ptr, rr->rdlength, limit); return(mDNSNULL);} + + // No compression allowed for "nxt", just copy the data. + mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); + return(ptr + rr->rdlength); + } + } + + default: debugf("putRData: Warning! Writing unknown resource type %d as raw data", rr->rrtype); + if (ptr + rr->rdlength > limit) return(mDNSNULL); + mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); + return(ptr + rr->rdlength); + } +} + +#define IsUnicastUpdate(X) (!mDNSOpaque16IsZero((X)->h.id) && ((X)->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update) + +mDNSexport mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit) +{ + mDNSu8 *endofrdata; + mDNSu16 actualLength; + // When sending SRV to conventional DNS server (i.e. in DNS update requests) we should not do name compression on the rdata (RFC 2782) + const DNSMessage *const rdatacompressionbase = (IsUnicastUpdate(msg) && rr->rrtype == kDNSType_SRV) ? mDNSNULL : msg; + + if (rr->RecordType == kDNSRecordTypeUnregistered) + { + LogMsg("PutResourceRecordTTLWithLimit ERROR! Attempt to put kDNSRecordTypeUnregistered %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); + return(ptr); + } + + if (!ptr) + { + LogMsg("PutResourceRecordTTLWithLimit ptr is null %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); + return(mDNSNULL); + } + + ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name); + // If we're out-of-space, return mDNSNULL + if (!ptr || ptr + 10 >= limit) + { + LogInfo("PutResourceRecordTTLWithLimit: can't put name, out of space %##s (%s), ptr %p, limit %p", rr->name->c, + DNSTypeName(rr->rrtype), ptr, limit); + return(mDNSNULL); + } + ptr[0] = (mDNSu8)(rr->rrtype >> 8); + ptr[1] = (mDNSu8)(rr->rrtype & 0xFF); + ptr[2] = (mDNSu8)(rr->rrclass >> 8); + ptr[3] = (mDNSu8)(rr->rrclass & 0xFF); + ptr[4] = (mDNSu8)((ttl >> 24) & 0xFF); + ptr[5] = (mDNSu8)((ttl >> 16) & 0xFF); + ptr[6] = (mDNSu8)((ttl >> 8) & 0xFF); + ptr[7] = (mDNSu8)( ttl & 0xFF); + // ptr[8] and ptr[9] filled in *after* we find out how much space the rdata takes + + endofrdata = putRData(rdatacompressionbase, ptr+10, limit, rr); + if (!endofrdata) + { + LogInfo("PutResourceRecordTTLWithLimit: Ran out of space in PutResourceRecord for %##s (%s), ptr %p, limit %p", rr->name->c, + DNSTypeName(rr->rrtype), ptr+10, limit); + return(mDNSNULL); + } + + // Go back and fill in the actual number of data bytes we wrote + // (actualLength can be less than rdlength when domain name compression is used) + actualLength = (mDNSu16)(endofrdata - ptr - 10); + ptr[8] = (mDNSu8)(actualLength >> 8); + ptr[9] = (mDNSu8)(actualLength & 0xFF); + + if (count) (*count)++; + else LogMsg("PutResourceRecordTTL: ERROR: No target count to update for %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); + return(endofrdata); +} + +mDNSlocal mDNSu8 *putEmptyResourceRecord(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, mDNSu16 *count, const AuthRecord *rr) +{ + ptr = putDomainNameAsLabels(msg, ptr, limit, rr->resrec.name); + if (!ptr || ptr + 10 > limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL + ptr[0] = (mDNSu8)(rr->resrec.rrtype >> 8); // Put type + ptr[1] = (mDNSu8)(rr->resrec.rrtype & 0xFF); + ptr[2] = (mDNSu8)(rr->resrec.rrclass >> 8); // Put class + ptr[3] = (mDNSu8)(rr->resrec.rrclass & 0xFF); + ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // TTL is zero + ptr[8] = ptr[9] = 0; // RDATA length is zero + (*count)++; + return(ptr + 10); +} + +mDNSexport mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass) +{ + ptr = putDomainNameAsLabels(msg, ptr, limit, name); + if (!ptr || ptr+4 >= limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL + ptr[0] = (mDNSu8)(rrtype >> 8); + ptr[1] = (mDNSu8)(rrtype & 0xFF); + ptr[2] = (mDNSu8)(rrclass >> 8); + ptr[3] = (mDNSu8)(rrclass & 0xFF); + msg->h.numQuestions++; + return(ptr+4); +} + +// for dynamic updates +mDNSexport mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass) +{ + ptr = putDomainNameAsLabels(msg, ptr, limit, zone); + if (!ptr || ptr + 4 > limit) return mDNSNULL; // If we're out-of-space, return NULL + *ptr++ = (mDNSu8)(kDNSType_SOA >> 8); + *ptr++ = (mDNSu8)(kDNSType_SOA & 0xFF); + *ptr++ = zoneClass.b[0]; + *ptr++ = zoneClass.b[1]; + msg->h.mDNS_numZones++; + return ptr; +} + +// for dynamic updates +mDNSexport mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *const msg, mDNSu8 *const ptr, mDNSu8 *const end) +{ + AuthRecord prereq; + mDNS_SetupResourceRecord(&prereq, mDNSNULL, mDNSInterface_Any, kDNSQType_ANY, kStandardTTL, 0, AuthRecordAny, mDNSNULL, mDNSNULL); + AssignDomainName(&prereq.namestorage, name); + prereq.resrec.rrtype = kDNSQType_ANY; + prereq.resrec.rrclass = kDNSClass_NONE; + return putEmptyResourceRecord(msg, ptr, end, &msg->h.mDNS_numPrereqs, &prereq); +} + +// for dynamic updates +mDNSexport mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr) +{ + // deletion: specify record w/ TTL 0, class NONE + const mDNSu16 origclass = rr->rrclass; + rr->rrclass = kDNSClass_NONE; + ptr = PutResourceRecordTTLJumbo(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0); + rr->rrclass = origclass; + return ptr; +} + +// for dynamic updates +mDNSexport mDNSu8 *putDeletionRecordWithLimit(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr, mDNSu8 *limit) +{ + // deletion: specify record w/ TTL 0, class NONE + const mDNSu16 origclass = rr->rrclass; + rr->rrclass = kDNSClass_NONE; + ptr = PutResourceRecordTTLWithLimit(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0, limit); + rr->rrclass = origclass; + return ptr; +} + +mDNSexport mDNSu8 *putDeleteRRSetWithLimit(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype, mDNSu8 *limit) +{ + mDNSu16 class = kDNSQClass_ANY; + + ptr = putDomainNameAsLabels(msg, ptr, limit, name); + if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL + ptr[0] = (mDNSu8)(rrtype >> 8); + ptr[1] = (mDNSu8)(rrtype & 0xFF); + ptr[2] = (mDNSu8)(class >> 8); + ptr[3] = (mDNSu8)(class & 0xFF); + ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl + ptr[8] = ptr[9] = 0; // zero rdlength/rdata + + msg->h.mDNS_numUpdates++; + return ptr + 10; +} + +// for dynamic updates +mDNSexport mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name) +{ + const mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData; + mDNSu16 class = kDNSQClass_ANY; + mDNSu16 rrtype = kDNSQType_ANY; + + ptr = putDomainNameAsLabels(msg, ptr, limit, name); + if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL + ptr[0] = (mDNSu8)(rrtype >> 8); + ptr[1] = (mDNSu8)(rrtype & 0xFF); + ptr[2] = (mDNSu8)(class >> 8); + ptr[3] = (mDNSu8)(class & 0xFF); + ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl + ptr[8] = ptr[9] = 0; // zero rdlength/rdata + + msg->h.mDNS_numUpdates++; + return ptr + 10; +} + +// for dynamic updates +mDNSexport mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease) +{ + AuthRecord rr; + mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); + rr.resrec.rrclass = NormalMaxDNSMessageData; + rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record + rr.resrec.rdestimate = sizeof(rdataOPT); + rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; + rr.resrec.rdata->u.opt[0].u.updatelease = lease; + end = PutResourceRecordTTLJumbo(msg, end, &msg->h.numAdditionals, &rr.resrec, 0); + if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTL"); return mDNSNULL; } + return end; +} + +// for dynamic updates +mDNSexport mDNSu8 *putUpdateLeaseWithLimit(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease, mDNSu8 *limit) +{ + AuthRecord rr; + mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); + rr.resrec.rrclass = NormalMaxDNSMessageData; + rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record + rr.resrec.rdestimate = sizeof(rdataOPT); + rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; + rr.resrec.rdata->u.opt[0].u.updatelease = lease; + end = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &rr.resrec, 0, limit); + if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTLWithLimit"); return mDNSNULL; } + return end; +} + +mDNSexport mDNSu8 *putDNSSECOption(DNSMessage *msg, mDNSu8 *end, mDNSu8 *limit) +{ + AuthRecord rr; + mDNSu32 ttl = 0; + + mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); + // It is still not clear what the right size is. We will have to fine tune this once we do + // a lot of testing with DNSSEC. + rr.resrec.rrclass = 4096; + rr.resrec.rdlength = 0; + rr.resrec.rdestimate = 0; + // set the DO bit + ttl |= 0x8000; + end = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &rr.resrec, ttl, limit); + if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTLWithLimit"); return mDNSNULL; } + return end; +} + +mDNSexport mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *end, DomainAuthInfo *authInfo, mDNSu8 *limit) +{ + if (authInfo && authInfo->AutoTunnel) + { + AuthRecord hinfo; + mDNSu8 *h = hinfo.rdatastorage.u.data; + mDNSu16 len = 2 + m->HIHardware.c[0] + m->HISoftware.c[0]; + mDNSu8 *newptr; + mDNS_SetupResourceRecord(&hinfo, mDNSNULL, mDNSInterface_Any, kDNSType_HINFO, 0, kDNSRecordTypeUnique, AuthRecordAny, mDNSNULL, mDNSNULL); + AppendDomainLabel(&hinfo.namestorage, &m->hostlabel); + AppendDomainName (&hinfo.namestorage, &authInfo->domain); + hinfo.resrec.rroriginalttl = 0; + mDNSPlatformMemCopy(h, &m->HIHardware, 1 + (mDNSu32)m->HIHardware.c[0]); + h += 1 + (int)h[0]; + mDNSPlatformMemCopy(h, &m->HISoftware, 1 + (mDNSu32)m->HISoftware.c[0]); + hinfo.resrec.rdlength = len; + hinfo.resrec.rdestimate = len; + newptr = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &hinfo.resrec, 0, limit); + return newptr; + } + else + return end; +} + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - DNS Message Parsing Functions +#endif + +mDNSexport mDNSu32 DomainNameHashValue(const domainname *const name) +{ + mDNSu32 sum = 0; + const mDNSu8 *c; + + for (c = name->c; c[0] != 0 && c[1] != 0; c += 2) + { + sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8) | + (mDNSIsUpperCase(c[1]) ? c[1] + 'a' - 'A' : c[1]); + sum = (sum<<3) | (sum>>29); + } + if (c[0]) sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8); + return(sum); +} + +mDNSexport void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength) +{ + domainname *target; + if (NewRData) + { + rr->rdata = NewRData; + rr->rdlength = rdlength; + } + // Must not try to get target pointer until after updating rr->rdata + target = GetRRDomainNameTarget(rr); + rr->rdlength = GetRDLength(rr, mDNSfalse); + rr->rdestimate = GetRDLength(rr, mDNStrue); + rr->rdatahash = target ? DomainNameHashValue(target) : RDataHashValue(rr); +} + +mDNSexport const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end) +{ + mDNSu16 total = 0; + + if (ptr < (mDNSu8*)msg || ptr >= end) + { debugf("skipDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); } + + while (1) // Read sequence of labels + { + const mDNSu8 len = *ptr++; // Read length of this label + if (len == 0) return(ptr); // If length is zero, that means this name is complete + switch (len & 0xC0) + { + case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label + { debugf("skipDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); } + if (total + 1 + len >= MAX_DOMAIN_NAME) // Remember: expect at least one more byte for the root label + { debugf("skipDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); } + ptr += len; + total += 1 + len; + break; + + case 0x40: debugf("skipDomainName: Extended EDNS0 label types 0x%X not supported", len); return(mDNSNULL); + case 0x80: debugf("skipDomainName: Illegal label length 0x%X", len); return(mDNSNULL); + case 0xC0: return(ptr+1); + } + } +} + +// Routine to fetch an FQDN from the DNS message, following compression pointers if necessary. +mDNSexport const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, + domainname *const name) +{ + const mDNSu8 *nextbyte = mDNSNULL; // Record where we got to before we started following pointers + mDNSu8 *np = name->c; // Name pointer + const mDNSu8 *const limit = np + MAX_DOMAIN_NAME; // Limit so we don't overrun buffer + + if (ptr < (mDNSu8*)msg || ptr >= end) + { debugf("getDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); } + + *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels) + + while (1) // Read sequence of labels + { + const mDNSu8 len = *ptr++; // Read length of this label + if (len == 0) break; // If length is zero, that means this name is complete + switch (len & 0xC0) + { + int i; + mDNSu16 offset; + + case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label + { debugf("getDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); } + if (np + 1 + len >= limit) // Remember: expect at least one more byte for the root label + { debugf("getDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); } + *np++ = len; + for (i=0; i<len; i++) *np++ = *ptr++; + *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels) + break; + + case 0x40: debugf("getDomainName: Extended EDNS0 label types 0x%X not supported in name %##s", len, name->c); + return(mDNSNULL); + + case 0x80: debugf("getDomainName: Illegal label length 0x%X in domain name %##s", len, name->c); return(mDNSNULL); + + case 0xC0: offset = (mDNSu16)((((mDNSu16)(len & 0x3F)) << 8) | *ptr++); + if (!nextbyte) nextbyte = ptr; // Record where we got to before we started following pointers + ptr = (mDNSu8 *)msg + offset; + if (ptr < (mDNSu8*)msg || ptr >= end) + { debugf("getDomainName: Illegal compression pointer not within packet boundaries"); return(mDNSNULL); } + if (*ptr & 0xC0) + { debugf("getDomainName: Compression pointer must point to real label"); return(mDNSNULL); } + break; + } + } + + if (nextbyte) return(nextbyte); + else return(ptr); +} + +mDNSexport const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end) +{ + mDNSu16 pktrdlength; + + ptr = skipDomainName(msg, ptr, end); + if (!ptr) { debugf("skipResourceRecord: Malformed RR name"); return(mDNSNULL); } + + if (ptr + 10 > end) { debugf("skipResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); } + pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]); + ptr += 10; + if (ptr + pktrdlength > end) { debugf("skipResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); } + + return(ptr + pktrdlength); +} + +// Sanity check whether the NSEC/NSEC3 bitmap is good +mDNSlocal mDNSu8 *SanityCheckBitMap(const mDNSu8 *bmap, const mDNSu8 *end, int len) +{ + int win, wlen; + + while (bmap < end) + { + if (len < 3) + { + LogInfo("SanityCheckBitMap: invalid length %d", len); + return mDNSNULL; + } + + win = *bmap++; + wlen = *bmap++; + len -= 2; + if (len < wlen || wlen < 1 || wlen > 32) + { + LogInfo("SanityCheckBitMap: invalid window length %d", wlen); + return mDNSNULL; + } + if (win < 0 || win >= 256) + { + LogInfo("SanityCheckBitMap: invalid window %d", win); + return mDNSNULL; + } + + bmap += wlen; + len -= wlen; + } + return (mDNSu8 *)bmap; +} + +// This function is called with "msg" when we receive a DNS message and needs to parse a single resource record +// pointed to by "ptr". Some resource records like SOA, SRV are converted to host order and also expanded +// (domainnames are expanded to 255 bytes) when stored in memory. +// +// This function can also be called with "NULL" msg to parse a single resource record pointed to by ptr. +// The caller can do this only if the names in the resource records are compressed and validity of the +// resource record has already been done before. DNSSEC currently uses it this way. +mDNSexport mDNSBool SetRData(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *end, + LargeCacheRecord *const largecr, mDNSu16 rdlength) +{ + CacheRecord *const rr = &largecr->r; + RDataBody2 *const rdb = (RDataBody2 *)rr->smallrdatastorage.data; + + switch (rr->resrec.rrtype) + { + case kDNSType_A: + if (rdlength != sizeof(mDNSv4Addr)) + goto fail; + rdb->ipv4.b[0] = ptr[0]; + rdb->ipv4.b[1] = ptr[1]; + rdb->ipv4.b[2] = ptr[2]; + rdb->ipv4.b[3] = ptr[3]; + break; + + case kDNSType_NS: + case kDNSType_MD: + case kDNSType_MF: + case kDNSType_CNAME: + case kDNSType_MB: + case kDNSType_MG: + case kDNSType_MR: + case kDNSType_PTR: + case kDNSType_NSAP_PTR: + case kDNSType_DNAME: + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->name); + } + else + { + AssignDomainName(&rdb->name, (domainname *)ptr); + ptr += DomainNameLength(&rdb->name); + } + if (ptr != end) + { + debugf("SetRData: Malformed CNAME/PTR RDATA name"); + goto fail; + } + break; + + case kDNSType_SOA: + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->soa.mname); + } + else + { + AssignDomainName(&rdb->soa.mname, (domainname *)ptr); + ptr += DomainNameLength(&rdb->soa.mname); + } + if (!ptr) + { + debugf("SetRData: Malformed SOA RDATA mname"); + goto fail; + } + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->soa.rname); + } + else + { + AssignDomainName(&rdb->soa.rname, (domainname *)ptr); + ptr += DomainNameLength(&rdb->soa.rname); + } + if (!ptr) + { + debugf("SetRData: Malformed SOA RDATA rname"); + goto fail; + } + if (ptr + 0x14 != end) + { + debugf("SetRData: Malformed SOA RDATA"); + goto fail; + } + rdb->soa.serial = (mDNSs32) ((mDNSs32)ptr[0x00] << 24 | (mDNSs32)ptr[0x01] << 16 | (mDNSs32)ptr[0x02] << 8 | ptr[0x03]); + rdb->soa.refresh = (mDNSu32) ((mDNSu32)ptr[0x04] << 24 | (mDNSu32)ptr[0x05] << 16 | (mDNSu32)ptr[0x06] << 8 | ptr[0x07]); + rdb->soa.retry = (mDNSu32) ((mDNSu32)ptr[0x08] << 24 | (mDNSu32)ptr[0x09] << 16 | (mDNSu32)ptr[0x0A] << 8 | ptr[0x0B]); + rdb->soa.expire = (mDNSu32) ((mDNSu32)ptr[0x0C] << 24 | (mDNSu32)ptr[0x0D] << 16 | (mDNSu32)ptr[0x0E] << 8 | ptr[0x0F]); + rdb->soa.min = (mDNSu32) ((mDNSu32)ptr[0x10] << 24 | (mDNSu32)ptr[0x11] << 16 | (mDNSu32)ptr[0x12] << 8 | ptr[0x13]); + break; + + case kDNSType_NULL: + case kDNSType_HINFO: + case kDNSType_TXT: + case kDNSType_X25: + case kDNSType_ISDN: + case kDNSType_LOC: + case kDNSType_DHCID: + rr->resrec.rdlength = rdlength; + mDNSPlatformMemCopy(rdb->data, ptr, rdlength); + break; + + case kDNSType_MX: + case kDNSType_AFSDB: + case kDNSType_RT: + case kDNSType_KX: + // Preference + domainname + if (rdlength < 3) + goto fail; + rdb->mx.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); + ptr += 2; + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->mx.exchange); + } + else + { + AssignDomainName(&rdb->mx.exchange, (domainname *)ptr); + ptr += DomainNameLength(&rdb->mx.exchange); + } + if (ptr != end) + { + debugf("SetRData: Malformed MX name"); + goto fail; + } + break; + + case kDNSType_MINFO: + case kDNSType_RP: + // Domainname + domainname + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->rp.mbox); + } + else + { + AssignDomainName(&rdb->rp.mbox, (domainname *)ptr); + ptr += DomainNameLength(&rdb->rp.mbox); + } + if (!ptr) + { + debugf("SetRData: Malformed RP mbox"); + goto fail; + } + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->rp.txt); + } + else + { + AssignDomainName(&rdb->rp.txt, (domainname *)ptr); + ptr += DomainNameLength(&rdb->rp.txt); + } + if (ptr != end) + { + debugf("SetRData: Malformed RP txt"); + goto fail; + } + break; + + case kDNSType_PX: + // Preference + domainname + domainname + if (rdlength < 4) + goto fail; + rdb->px.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); + ptr += 2; + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->px.map822); + } + else + { + AssignDomainName(&rdb->px.map822, (domainname *)ptr); + ptr += DomainNameLength(&rdb->px.map822); + } + if (!ptr) + { + debugf("SetRData: Malformed PX map822"); + goto fail; + } + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->px.mapx400); + } + else + { + AssignDomainName(&rdb->px.mapx400, (domainname *)ptr); + ptr += DomainNameLength(&rdb->px.mapx400); + } + if (ptr != end) + { + debugf("SetRData: Malformed PX mapx400"); + goto fail; + } + break; + + case kDNSType_AAAA: + if (rdlength != sizeof(mDNSv6Addr)) + goto fail; + mDNSPlatformMemCopy(&rdb->ipv6, ptr, sizeof(rdb->ipv6)); + break; + + case kDNSType_SRV: + // Priority + weight + port + domainname + if (rdlength < 7) + goto fail; + rdb->srv.priority = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); + rdb->srv.weight = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); + rdb->srv.port.b[0] = ptr[4]; + rdb->srv.port.b[1] = ptr[5]; + ptr += 6; + if (msg) + { + ptr = getDomainName(msg, ptr, end, &rdb->srv.target); + } + else + { + AssignDomainName(&rdb->srv.target, (domainname *)ptr); + ptr += DomainNameLength(&rdb->srv.target); + } + if (ptr != end) + { + debugf("SetRData: Malformed SRV RDATA name"); + goto fail; + } + break; + + case kDNSType_NAPTR: + { + int savelen, len; + domainname name; + const mDNSu8 *orig = ptr; + + // Make sure the data is parseable and within the limits. DNSSEC code looks at + // the domain name in the end for a valid domainname. + // + // Fixed length: Order, preference (4 bytes) + // Variable length: flags, service, regexp, domainname + + if (rdlength < 8) + goto fail; + // Order, preference. + ptr += 4; + // Parse flags, Service and Regexp + // length in the first byte does not include the length byte itself + len = *ptr + 1; + ptr += len; + if (ptr >= end) + { + LogInfo("SetRData: Malformed NAPTR flags"); + goto fail; + } + + // Service + len = *ptr + 1; + ptr += len; + if (ptr >= end) + { + LogInfo("SetRData: Malformed NAPTR service"); + goto fail; + } + + // Regexp + len = *ptr + 1; + ptr += len; + if (ptr >= end) + { + LogInfo("SetRData: Malformed NAPTR regexp"); + goto fail; + } + + savelen = ptr - orig; + + // RFC 2915 states that name compression is not allowed for this field. But RFC 3597 + // states that for NAPTR we should decompress. We make sure that we store the full + // name rather than the compressed name + if (msg) + { + ptr = getDomainName(msg, ptr, end, &name); + } + else + { + AssignDomainName(&name, (domainname *)ptr); + ptr += DomainNameLength(&name); + } + if (ptr != end) + { + LogInfo("SetRData: Malformed NAPTR RDATA name"); + goto fail; + } + + rr->resrec.rdlength = savelen + DomainNameLength(&name); + // The uncompressed size should not exceed the limits + if (rr->resrec.rdlength > MaximumRDSize) + { + LogInfo("SetRData: Malformed NAPTR rdlength %d, rr->resrec.rdlength %d, " + "bmaplen %d, name %##s", rdlength, rr->resrec.rdlength, name.c); + goto fail; + } + mDNSPlatformMemCopy(rdb->data, orig, savelen); + AssignDomainName((domainname *)(rdb->data + savelen), &name); + break; + } + case kDNSType_OPT: { + mDNSu8 *dataend = rr->resrec.rdata->u.data; + rdataOPT *opt = rr->resrec.rdata->u.opt; + rr->resrec.rdlength = 0; + while (ptr < end && (mDNSu8 *)(opt+1) < &dataend[MaximumRDSize]) + { + const rdataOPT *const currentopt = opt; + if (ptr + 4 > end) { LogInfo("SetRData: OPT RDATA ptr + 4 > end"); goto fail; } + opt->opt = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); + opt->optlen = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); + ptr += 4; + if (ptr + opt->optlen > end) { LogInfo("SetRData: ptr + opt->optlen > end"); goto fail; } + switch (opt->opt) + { + case kDNSOpt_LLQ: + if (opt->optlen == DNSOpt_LLQData_Space - 4) + { + opt->u.llq.vers = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); + opt->u.llq.llqOp = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); + opt->u.llq.err = (mDNSu16)((mDNSu16)ptr[4] << 8 | ptr[5]); + mDNSPlatformMemCopy(opt->u.llq.id.b, ptr+6, 8); + opt->u.llq.llqlease = (mDNSu32) ((mDNSu32)ptr[14] << 24 | (mDNSu32)ptr[15] << 16 | (mDNSu32)ptr[16] << 8 | ptr[17]); + if (opt->u.llq.llqlease > 0x70000000UL / mDNSPlatformOneSecond) + opt->u.llq.llqlease = 0x70000000UL / mDNSPlatformOneSecond; + opt++; + } + break; + case kDNSOpt_Lease: + if (opt->optlen == DNSOpt_LeaseData_Space - 4) + { + opt->u.updatelease = (mDNSu32) ((mDNSu32)ptr[0] << 24 | (mDNSu32)ptr[1] << 16 | (mDNSu32)ptr[2] << 8 | ptr[3]); + if (opt->u.updatelease > 0x70000000UL / mDNSPlatformOneSecond) + opt->u.updatelease = 0x70000000UL / mDNSPlatformOneSecond; + opt++; + } + break; + case kDNSOpt_Owner: + if (ValidOwnerLength(opt->optlen)) + { + opt->u.owner.vers = ptr[0]; + opt->u.owner.seq = ptr[1]; + mDNSPlatformMemCopy(opt->u.owner.HMAC.b, ptr+2, 6); // 6-byte MAC address + mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+2, 6); // 6-byte MAC address + opt->u.owner.password = zeroEthAddr; + if (opt->optlen >= DNSOpt_OwnerData_ID_Wake_Space-4) + { + mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+8, 6); // 6-byte MAC address + // This mDNSPlatformMemCopy is safe because the ValidOwnerLength(opt->optlen) check above + // ensures that opt->optlen is no more than DNSOpt_OwnerData_ID_Wake_PW6_Space - 4 + if (opt->optlen > DNSOpt_OwnerData_ID_Wake_Space-4) + mDNSPlatformMemCopy(opt->u.owner.password.b, ptr+14, opt->optlen - (DNSOpt_OwnerData_ID_Wake_Space-4)); + } + opt++; + } + break; + case kDNSOpt_Trace: + if (opt->optlen == DNSOpt_TraceData_Space - 4) + { + opt->u.tracer.platf = ptr[0]; + opt->u.tracer.mDNSv = (mDNSu32) ((mDNSu32)ptr[1] << 24 | (mDNSu32)ptr[2] << 16 | (mDNSu32)ptr[3] << 8 | ptr[4]); + opt++; + } + break; + } + ptr += currentopt->optlen; + } + rr->resrec.rdlength = (mDNSu16)((mDNSu8*)opt - rr->resrec.rdata->u.data); + if (ptr != end) { LogInfo("SetRData: Malformed OptRdata"); goto fail; } + break; + } + + case kDNSType_NSEC: { + domainname name; + int len = rdlength; + int bmaplen, dlen; + const mDNSu8 *orig = ptr; + const mDNSu8 *bmap; + + if (msg) + { + ptr = getDomainName(msg, ptr, end, &name); + } + else + { + AssignDomainName(&name, (domainname *)ptr); + ptr += DomainNameLength(&name); + } + if (!ptr) + { + LogInfo("SetRData: Malformed NSEC nextname"); + goto fail; + } + + dlen = DomainNameLength(&name); + + // Multicast NSECs use name compression for this field unlike the unicast case which + // does not use compression. And multicast case always succeeds in compression. So, + // the rdlength includes only the compressed space in that case. So, can't + // use the DomainNameLength of name to reduce the length here. + len -= (ptr - orig); + bmaplen = len; // Save the length of the bitmap + bmap = ptr; + ptr = SanityCheckBitMap(bmap, end, len); + if (!ptr) + goto fail; + if (ptr != end) + { + LogInfo("SetRData: Malformed NSEC length not right"); + goto fail; + } + + // Initialize the right length here. When we call SetNewRData below which in turn calls + // GetRDLength and for NSEC case, it assumes that rdlength is intitialized + rr->resrec.rdlength = DomainNameLength(&name) + bmaplen; + + // Do we have space after the name expansion ? + if (rr->resrec.rdlength > MaximumRDSize) + { + LogInfo("SetRData: Malformed NSEC rdlength %d, rr->resrec.rdlength %d, " + "bmaplen %d, name %##s", rdlength, rr->resrec.rdlength, name.c); + goto fail; + } + AssignDomainName((domainname *)rdb->data, &name); + mDNSPlatformMemCopy(rdb->data + dlen, bmap, bmaplen); + break; + } + case kDNSType_NSEC3: + { + rdataNSEC3 *nsec3 = (rdataNSEC3 *)ptr; + mDNSu8 *p = (mDNSu8 *)&nsec3->salt; + int hashLength, bitmaplen; + + if (rdlength < NSEC3_FIXED_SIZE + 1) + { + LogInfo("SetRData: NSEC3 too small length %d", rdlength); + goto fail; + } + if (nsec3->alg != SHA1_DIGEST_TYPE) + { + LogInfo("SetRData: nsec3 alg %d not supported", nsec3->alg); + goto fail; + } + if (swap16(nsec3->iterations) > NSEC3_MAX_ITERATIONS) + { + LogInfo("SetRData: nsec3 iteration count %d too big", swap16(nsec3->iterations)); + goto fail; + } + p += nsec3->saltLength; + // There should at least be one byte beyond saltLength + if (p >= end) + { + LogInfo("SetRData: nsec3 too small, at saltlength %d, p %p, end %p", nsec3->saltLength, p, end); + goto fail; + } + // p is pointing at hashLength + hashLength = (int)*p++; + if (!hashLength) + { + LogInfo("SetRData: hashLength zero"); + goto fail; + } + p += hashLength; + if (p > end) + { + LogInfo("SetRData: nsec3 too small, at hashLength %d, p %p, end %p", hashLength, p, end); + goto fail; + } + + bitmaplen = rdlength - (int)(p - ptr); + p = SanityCheckBitMap(p, end, bitmaplen); + if (!p) + goto fail; + rr->resrec.rdlength = rdlength; + mDNSPlatformMemCopy(rdb->data, ptr, rdlength); + break; + } + case kDNSType_TKEY: + case kDNSType_TSIG: + { + domainname name; + int dlen, rlen; + + // The name should not be compressed. But we take the conservative approach + // and uncompress the name before we store it. + if (msg) + { + ptr = getDomainName(msg, ptr, end, &name); + } + else + { + AssignDomainName(&name, (domainname *)ptr); + ptr += DomainNameLength(&name); + } + if (!ptr) + { + LogInfo("SetRData: Malformed name for TSIG/TKEY type %d", rr->resrec.rrtype); + goto fail; + } + dlen = DomainNameLength(&name); + rlen = end - ptr; + rr->resrec.rdlength = dlen + rlen; + AssignDomainName((domainname *)rdb->data, &name); + mDNSPlatformMemCopy(rdb->data + dlen, ptr, rlen); + break; + } + case kDNSType_RRSIG: + { + const mDNSu8 *sig = ptr + RRSIG_FIXED_SIZE; + const mDNSu8 *orig = sig; + domainname name; + if (rdlength < RRSIG_FIXED_SIZE + 1) + { + LogInfo("SetRData: RRSIG too small length %d", rdlength); + goto fail; + } + if (msg) + { + sig = getDomainName(msg, sig, end, &name); + } + else + { + AssignDomainName(&name, (domainname *)sig); + sig += DomainNameLength(&name); + } + if (!sig) + { + LogInfo("SetRData: Malformed RRSIG record"); + goto fail; + } + + if ((sig - orig) != DomainNameLength(&name)) + { + LogInfo("SetRData: Malformed RRSIG record, signer name compression"); + goto fail; + } + // Just ensure that we have at least one byte of the signature + if (sig + 1 >= end) + { + LogInfo("SetRData: Not enough bytes for signature type %d", rr->resrec.rrtype); + goto fail; + } + rr->resrec.rdlength = rdlength; + mDNSPlatformMemCopy(rdb->data, ptr, rdlength); + break; + } + case kDNSType_DNSKEY: + { + if (rdlength < DNSKEY_FIXED_SIZE + 1) + { + LogInfo("SetRData: DNSKEY too small length %d", rdlength); + goto fail; + } + rr->resrec.rdlength = rdlength; + mDNSPlatformMemCopy(rdb->data, ptr, rdlength); + break; + } + case kDNSType_DS: + { + if (rdlength < DS_FIXED_SIZE + 1) + { + LogInfo("SetRData: DS too small length %d", rdlength); + goto fail; + } + rr->resrec.rdlength = rdlength; + mDNSPlatformMemCopy(rdb->data, ptr, rdlength); + break; + } + default: + debugf("SetRData: Warning! Reading resource type %d (%s) as opaque data", + rr->resrec.rrtype, DNSTypeName(rr->resrec.rrtype)); + // Note: Just because we don't understand the record type, that doesn't + // mean we fail. The DNS protocol specifies rdlength, so we can + // safely skip over unknown records and ignore them. + // We also grab a binary copy of the rdata anyway, since the caller + // might know how to interpret it even if we don't. + rr->resrec.rdlength = rdlength; + mDNSPlatformMemCopy(rdb->data, ptr, rdlength); + break; + } + return mDNStrue; +fail: + return mDNSfalse; +} + +mDNSexport const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr, + const mDNSu8 *end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *const largecr) +{ + CacheRecord *const rr = &largecr->r; + mDNSu16 pktrdlength; + + if (largecr == &m->rec && m->rec.r.resrec.RecordType) + { + LogMsg("GetLargeResourceRecord: m->rec appears to be already in use for %s", CRDisplayString(m, &m->rec.r)); +#if ForceAlerts + *(long*)0 = 0; +#endif + } + + rr->next = mDNSNULL; + rr->resrec.name = &largecr->namestorage; + + rr->NextInKAList = mDNSNULL; + rr->TimeRcvd = m ? m->timenow : 0; + rr->DelayDelivery = 0; + rr->NextRequiredQuery = m ? m->timenow : 0; // Will be updated to the real value when we call SetNextCacheCheckTimeForRecord() + rr->LastUsed = m ? m->timenow : 0; + rr->CRActiveQuestion = mDNSNULL; + rr->UnansweredQueries = 0; + rr->LastUnansweredTime= 0; +#if ENABLE_MULTI_PACKET_QUERY_SNOOPING + rr->MPUnansweredQ = 0; + rr->MPLastUnansweredQT= 0; + rr->MPUnansweredKA = 0; + rr->MPExpectingKA = mDNSfalse; +#endif + rr->NextInCFList = mDNSNULL; + + rr->resrec.InterfaceID = InterfaceID; + rr->resrec.rDNSServer = mDNSNULL; + + ptr = getDomainName(msg, ptr, end, &largecr->namestorage); // Will bail out correctly if ptr is NULL + if (!ptr) { debugf("GetLargeResourceRecord: Malformed RR name"); return(mDNSNULL); } + rr->resrec.namehash = DomainNameHashValue(rr->resrec.name); + + if (ptr + 10 > end) { debugf("GetLargeResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); } + + rr->resrec.rrtype = (mDNSu16) ((mDNSu16)ptr[0] << 8 | ptr[1]); + rr->resrec.rrclass = (mDNSu16)(((mDNSu16)ptr[2] << 8 | ptr[3]) & kDNSClass_Mask); + rr->resrec.rroriginalttl = (mDNSu32) ((mDNSu32)ptr[4] << 24 | (mDNSu32)ptr[5] << 16 | (mDNSu32)ptr[6] << 8 | ptr[7]); + if (rr->resrec.rroriginalttl > 0x70000000UL / mDNSPlatformOneSecond && (mDNSs32)rr->resrec.rroriginalttl != -1) + rr->resrec.rroriginalttl = 0x70000000UL / mDNSPlatformOneSecond; + // Note: We don't have to adjust m->NextCacheCheck here -- this is just getting a record into memory for + // us to look at. If we decide to copy it into the cache, then we'll update m->NextCacheCheck accordingly. + pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]); + + // If mDNS record has cache-flush bit set, we mark it unique + // For uDNS records, all are implicitly deemed unique (a single DNS server is always + // authoritative for the entire RRSet), unless this is a truncated response + if (ptr[2] & (kDNSClass_UniqueRRSet >> 8) || (!InterfaceID && !(msg->h.flags.b[0] & kDNSFlag0_TC))) + RecordType |= kDNSRecordTypePacketUniqueMask; + ptr += 10; + if (ptr + pktrdlength > end) { debugf("GetLargeResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); } + end = ptr + pktrdlength; // Adjust end to indicate the end of the rdata for this resource record + + rr->resrec.rdata = (RData*)&rr->smallrdatastorage; + rr->resrec.rdata->MaxRDLength = MaximumRDSize; + + if (pktrdlength > MaximumRDSize) + { + LogInfo("GetLargeResourceRecord: %s rdata size (%d) exceeds storage (%d)", + DNSTypeName(rr->resrec.rrtype), pktrdlength, rr->resrec.rdata->MaxRDLength); + goto fail; + } + + if (!RecordType) LogMsg("GetLargeResourceRecord: No RecordType for %##s", rr->resrec.name->c); + + // IMPORTANT: Any record type we understand and unpack into a structure containing domainnames needs to have corresponding + // cases in SameRDataBody() and RDataHashValue() to do a semantic comparison (or checksum) of the structure instead of a blind + // bitwise memory compare (or sum). This is because a domainname is a fixed size structure holding variable-length data. + // Any bytes past the logical end of the name are undefined, and a blind bitwise memory compare may indicate that + // two domainnames are different when semantically they are the same name and it's only the unused bytes that differ. + if (rr->resrec.rrclass == kDNSQClass_ANY && pktrdlength == 0) // Used in update packets to mean "Delete An RRset" (RFC 2136) + rr->resrec.rdlength = 0; + else if (!SetRData(msg, ptr, end, largecr, pktrdlength)) + goto fail; + + SetNewRData(&rr->resrec, mDNSNULL, 0); // Sets rdlength, rdestimate, rdatahash for us + + // Success! Now fill in RecordType to show this record contains valid data + rr->resrec.RecordType = RecordType; + return(end); + +fail: + // If we were unable to parse the rdata in this record, we indicate that by + // returing a 'kDNSRecordTypePacketNegative' record with rdlength set to zero + rr->resrec.RecordType = kDNSRecordTypePacketNegative; + rr->resrec.rdlength = 0; + rr->resrec.rdestimate = 0; + rr->resrec.rdatahash = 0; + return(end); +} + +mDNSexport const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end) +{ + ptr = skipDomainName(msg, ptr, end); + if (!ptr) { debugf("skipQuestion: Malformed domain name in DNS question section"); return(mDNSNULL); } + if (ptr+4 > end) { debugf("skipQuestion: Malformed DNS question section -- no query type and class!"); return(mDNSNULL); } + return(ptr+4); +} + +mDNSexport const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID, + DNSQuestion *question) +{ + mDNSPlatformMemZero(question, sizeof(*question)); + question->InterfaceID = InterfaceID; + if (!InterfaceID) question->TargetQID = onesID; // In DNSQuestions we use TargetQID as the indicator of whether it's unicast or multicast + ptr = getDomainName(msg, ptr, end, &question->qname); + if (!ptr) { debugf("Malformed domain name in DNS question section"); return(mDNSNULL); } + if (ptr+4 > end) { debugf("Malformed DNS question section -- no query type and class!"); return(mDNSNULL); } + + question->qnamehash = DomainNameHashValue(&question->qname); + question->qtype = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); // Get type + question->qclass = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); // and class + return(ptr+4); +} + +mDNSexport const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end) +{ + int i; + const mDNSu8 *ptr = msg->data; + for (i = 0; i < msg->h.numQuestions && ptr; i++) ptr = skipQuestion(msg, ptr, end); + return(ptr); +} + +mDNSexport const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end) +{ + int i; + const mDNSu8 *ptr = LocateAnswers(msg, end); + for (i = 0; i < msg->h.numAnswers && ptr; i++) ptr = skipResourceRecord(msg, ptr, end); + return(ptr); +} + +mDNSexport const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end) +{ + int i; + const mDNSu8 *ptr = LocateAuthorities(msg, end); + for (i = 0; i < msg->h.numAuthorities; i++) ptr = skipResourceRecord(msg, ptr, end); + return (ptr); +} + +mDNSexport const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize) +{ + int i; + const mDNSu8 *ptr = LocateAdditionals(msg, end); + + // Locate the OPT record. + // According to RFC 2671, "One OPT pseudo-RR can be added to the additional data section of either a request or a response." + // This implies that there may be *at most* one OPT record per DNS message, in the Additional Section, + // but not necessarily the *last* entry in the Additional Section. + for (i = 0; ptr && i < msg->h.numAdditionals; i++) + { + if (ptr + DNSOpt_Header_Space + minsize <= end && // Make sure we have 11+minsize bytes of data + ptr[0] == 0 && // Name must be root label + ptr[1] == (kDNSType_OPT >> 8 ) && // rrtype OPT + ptr[2] == (kDNSType_OPT & 0xFF) && + ((mDNSu16)ptr[9] << 8 | (mDNSu16)ptr[10]) >= (mDNSu16)minsize) + return(ptr); + else + ptr = skipResourceRecord(msg, ptr, end); + } + return(mDNSNULL); +} + +// On success, GetLLQOptData returns pointer to storage within shared "m->rec"; +// it is caller's responsibilty to clear m->rec.r.resrec.RecordType after use +// Note: An OPT RDataBody actually contains one or more variable-length rdataOPT objects packed together +// The code that currently calls this assumes there's only one, instead of iterating through the set +mDNSexport const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end) +{ + const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LLQData_Space); + if (ptr) + { + ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec); + if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative) return(&m->rec.r.resrec.rdata->u.opt[0]); + } + return(mDNSNULL); +} + +// Get the lease life of records in a dynamic update +// returns 0 on error or if no lease present +mDNSexport mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end) +{ + mDNSu32 result = 0; + const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LeaseData_Space); + if (ptr) ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec); + if (ptr && m->rec.r.resrec.rdlength >= DNSOpt_LeaseData_Space && m->rec.r.resrec.rdata->u.opt[0].opt == kDNSOpt_Lease) + result = m->rec.r.resrec.rdata->u.opt[0].u.updatelease; + m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it + return(result); +} + +mDNSlocal const mDNSu8 *DumpRecords(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, int count, char *label) +{ + int i; + LogMsg("%2d %s", count, label); + for (i = 0; i < count && ptr; i++) + { + // This puts a LargeCacheRecord on the stack instead of using the shared m->rec storage, + // but since it's only used for debugging (and probably only on OS X, not on + // embedded systems) putting a 9kB object on the stack isn't a big problem. + LargeCacheRecord largecr; + ptr = GetLargeResourceRecord(m, msg, ptr, end, mDNSInterface_Any, kDNSRecordTypePacketAns, &largecr); + if (ptr) LogMsg("%2d TTL%8d %s", i, largecr.r.resrec.rroriginalttl, CRDisplayString(m, &largecr.r)); + } + if (!ptr) LogMsg("DumpRecords: ERROR: Premature end of packet data"); + return(ptr); +} + +#define DNS_OP_Name(X) ( \ + (X) == kDNSFlag0_OP_StdQuery ? "" : \ + (X) == kDNSFlag0_OP_Iquery ? "Iquery " : \ + (X) == kDNSFlag0_OP_Status ? "Status " : \ + (X) == kDNSFlag0_OP_Unused3 ? "Unused3 " : \ + (X) == kDNSFlag0_OP_Notify ? "Notify " : \ + (X) == kDNSFlag0_OP_Update ? "Update " : "?? " ) + +#define DNS_RC_Name(X) ( \ + (X) == kDNSFlag1_RC_NoErr ? "NoErr" : \ + (X) == kDNSFlag1_RC_FormErr ? "FormErr" : \ + (X) == kDNSFlag1_RC_ServFail ? "ServFail" : \ + (X) == kDNSFlag1_RC_NXDomain ? "NXDomain" : \ + (X) == kDNSFlag1_RC_NotImpl ? "NotImpl" : \ + (X) == kDNSFlag1_RC_Refused ? "Refused" : \ + (X) == kDNSFlag1_RC_YXDomain ? "YXDomain" : \ + (X) == kDNSFlag1_RC_YXRRSet ? "YXRRSet" : \ + (X) == kDNSFlag1_RC_NXRRSet ? "NXRRSet" : \ + (X) == kDNSFlag1_RC_NotAuth ? "NotAuth" : \ + (X) == kDNSFlag1_RC_NotZone ? "NotZone" : "??" ) + +// Note: DumpPacket expects the packet header fields in host byte order, not network byte order +mDNSexport void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport, + const mDNSAddr *srcaddr, mDNSIPPort srcport, + const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end) +{ + mDNSBool IsUpdate = ((msg->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update); + const mDNSu8 *ptr = msg->data; + int i; + DNSQuestion q; + char tbuffer[64], sbuffer[64], dbuffer[64] = ""; + if (!status) tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), sent ? "Sent" : "Received" )] = 0; + else tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), "ERROR %d %sing", status, sent ? "Send" : "Receive")] = 0; + if (sent) sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "port " )] = 0; + else sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "%#a:", srcaddr)] = 0; + if (dstaddr || !mDNSIPPortIsZero(dstport)) + dbuffer[mDNS_snprintf(dbuffer, sizeof(dbuffer), " to %#a:%d", dstaddr, mDNSVal16(dstport))] = 0; + + 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 --", + tbuffer, transport, + DNS_OP_Name(msg->h.flags.b[0] & kDNSFlag0_OP_Mask), + msg->h.flags.b[0] & kDNSFlag0_QR_Response ? "Response" : "Query", + msg->h.flags.b[0], msg->h.flags.b[1], + DNS_RC_Name(msg->h.flags.b[1] & kDNSFlag1_RC_Mask), + msg->h.flags.b[1] & kDNSFlag1_RC_Mask, + msg->h.flags.b[0] & kDNSFlag0_AA ? "AA " : "", + msg->h.flags.b[0] & kDNSFlag0_TC ? "TC " : "", + msg->h.flags.b[0] & kDNSFlag0_RD ? "RD " : "", + msg->h.flags.b[1] & kDNSFlag1_RA ? "RA " : "", + msg->h.flags.b[1] & kDNSFlag1_AD ? "AD " : "", + msg->h.flags.b[1] & kDNSFlag1_CD ? "CD " : "", + mDNSVal16(msg->h.id), + end - msg->data, + sbuffer, mDNSVal16(srcport), dbuffer, + (msg->h.flags.b[0] & kDNSFlag0_TC) ? " (truncated)" : "" + ); + + LogMsg("%2d %s", msg->h.numQuestions, IsUpdate ? "Zone" : "Questions"); + for (i = 0; i < msg->h.numQuestions && ptr; i++) + { + ptr = getQuestion(msg, ptr, end, mDNSInterface_Any, &q); + if (ptr) LogMsg("%2d %##s %s", i, q.qname.c, DNSTypeName(q.qtype)); + } + ptr = DumpRecords(m, msg, ptr, end, msg->h.numAnswers, IsUpdate ? "Prerequisites" : "Answers"); + ptr = DumpRecords(m, msg, ptr, end, msg->h.numAuthorities, IsUpdate ? "Updates" : "Authorities"); + ptr = DumpRecords(m, msg, ptr, end, msg->h.numAdditionals, "Additionals"); + LogMsg("--------------"); +} + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - Packet Sending Functions +#endif + +// Stub definition of TCPSocket_struct so we can access flags field. (Rest of TCPSocket_struct is platform-dependent.) +struct TCPSocket_struct { TCPSocketFlags flags; /* ... */ }; + +struct UDPSocket_struct +{ + mDNSIPPort port; // MUST BE FIRST FIELD -- mDNSCoreReceive expects every UDPSocket_struct to begin with mDNSIPPort port +}; + +// Note: When we sign a DNS message using DNSDigest_SignMessage(), the current real-time clock value is used, which +// is why we generally defer signing until we send the message, to ensure the signature is as fresh as possible. +mDNSexport mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end, + mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, + mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo, + mDNSBool useBackgroundTrafficClass) +{ + mStatus status = mStatus_NoError; + const mDNSu16 numAdditionals = msg->h.numAdditionals; + mDNSu8 *newend; + mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData; + +#if APPLE_OSX_mDNSResponder + // maintain outbound packet statistics + if (mDNSOpaque16IsZero(msg->h.id)) + m->MulticastPacketsSent++; + else + m->UnicastPacketsSent++; +#endif // APPLE_OSX_mDNSResponder + + // Zero-length message data is okay (e.g. for a DNS Update ack, where all we need is an ID and an error code + if (end < msg->data || end - msg->data > AbsoluteMaxDNSMessageData) + { + LogMsg("mDNSSendDNSMessage: invalid message %p %p %d", msg->data, end, end - msg->data); + return mStatus_BadParamErr; + } + + newend = putHINFO(m, msg, end, authInfo, limit); + if (!newend) LogMsg("mDNSSendDNSMessage: putHINFO failed msg %p end %p, limit %p", msg->data, end, limit); // Not fatal + else end = newend; + + // Put all the integer values in IETF byte-order (MSB first, LSB second) + SwapDNSHeaderBytes(msg); + + if (authInfo) DNSDigest_SignMessage(msg, &end, authInfo, 0); // DNSDigest_SignMessage operates on message in network byte order + if (!end) { LogMsg("mDNSSendDNSMessage: DNSDigest_SignMessage failed"); status = mStatus_NoMemoryErr; } + else + { + // Send the packet on the wire + if (!sock) + status = mDNSPlatformSendUDP(m, msg, end, InterfaceID, src, dst, dstport, useBackgroundTrafficClass); + else + { + mDNSu16 msglen = (mDNSu16)(end - (mDNSu8 *)msg); + mDNSu8 lenbuf[2] = { (mDNSu8)(msglen >> 8), (mDNSu8)(msglen & 0xFF) }; + char *buf; + long nsent; + + // Try to send them in one packet if we can allocate enough memory + buf = mDNSPlatformMemAllocate(msglen + 2); + if (buf) + { + buf[0] = lenbuf[0]; + buf[1] = lenbuf[1]; + mDNSPlatformMemCopy(buf+2, msg, msglen); + nsent = mDNSPlatformWriteTCP(sock, buf, msglen+2); + if (nsent != (msglen + 2)) + { + LogMsg("mDNSSendDNSMessage: write message failed %d/%d", nsent, msglen); + status = mStatus_ConnFailed; + } + mDNSPlatformMemFree(buf); + } + else + { + nsent = mDNSPlatformWriteTCP(sock, (char*)lenbuf, 2); + if (nsent != 2) + { + LogMsg("mDNSSendDNSMessage: write msg length failed %d/%d", nsent, 2); + status = mStatus_ConnFailed; + } + else + { + nsent = mDNSPlatformWriteTCP(sock, (char *)msg, msglen); + if (nsent != msglen) + { + LogMsg("mDNSSendDNSMessage: write msg body failed %d/%d", nsent, msglen); + status = mStatus_ConnFailed; + } + } + } + } + } + + // Swap the integer values back the way they were (remember that numAdditionals may have been changed by putHINFO and/or SignMessage) + SwapDNSHeaderBytes(msg); + + // Dump the packet with the HINFO and TSIG + if (mDNS_PacketLoggingEnabled && !mDNSOpaque16IsZero(msg->h.id)) + DumpPacket(m, status, mDNStrue, sock && (sock->flags & kTCPSocketFlags_UseTLS) ? "TLS" : sock ? "TCP" : "UDP", mDNSNULL, src ? src->port : MulticastDNSPort, dst, dstport, msg, end); + + // put the number of additionals back the way it was + msg->h.numAdditionals = numAdditionals; + + return(status); +} + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - RR List Management & Task Management +#endif + +mDNSexport void mDNS_Lock_(mDNS *const m, const char * const functionname) +{ + // MUST grab the platform lock FIRST! + mDNSPlatformLock(m); + + // Normally, mDNS_reentrancy is zero and so is mDNS_busy + // However, when we call a client callback mDNS_busy is one, and we increment mDNS_reentrancy too + // If that client callback does mDNS API calls, mDNS_reentrancy and mDNS_busy will both be one + // If mDNS_busy != mDNS_reentrancy that's a bad sign + if (m->mDNS_busy != m->mDNS_reentrancy) + { + LogMsg("%s: mDNS_Lock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy); +#if ForceAlerts + *(long*)0 = 0; +#endif + } + + // If this is an initial entry into the mDNSCore code, set m->timenow + // else, if this is a re-entrant entry into the mDNSCore code, m->timenow should already be set + if (m->mDNS_busy == 0) + { + if (m->timenow) + LogMsg("%s: mDNS_Lock: m->timenow already set (%ld/%ld)", functionname, m->timenow, mDNS_TimeNow_NoLock(m)); + m->timenow = mDNS_TimeNow_NoLock(m); + if (m->timenow == 0) m->timenow = 1; + } + else if (m->timenow == 0) + { + LogMsg("%s: mDNS_Lock: m->mDNS_busy is %ld but m->timenow not set", functionname, m->mDNS_busy); + m->timenow = mDNS_TimeNow_NoLock(m); + if (m->timenow == 0) m->timenow = 1; + } + + if (m->timenow_last - m->timenow > 0) + { + m->timenow_adjust += m->timenow_last - m->timenow; + LogMsg("%s: mDNSPlatformRawTime went backwards by %ld ticks; setting correction factor to %ld", functionname, m->timenow_last - m->timenow, m->timenow_adjust); + m->timenow = m->timenow_last; + } + m->timenow_last = m->timenow; + + // Increment mDNS_busy so we'll recognise re-entrant calls + m->mDNS_busy++; +} + +mDNSlocal AuthRecord *AnyLocalRecordReady(const mDNS *const m) +{ + AuthRecord *rr; + for (rr = m->NewLocalRecords; rr; rr = rr->next) + if (LocalRecordReady(rr)) return rr; + return mDNSNULL; +} + +mDNSlocal mDNSs32 GetNextScheduledEvent(const mDNS *const m) +{ + mDNSs32 e = m->timenow + 0x78000000; + if (m->mDNSPlatformStatus != mStatus_NoError) return(e); + if (m->NewQuestions) + { + if (m->NewQuestions->DelayAnswering) e = m->NewQuestions->DelayAnswering; + else return(m->timenow); + } + if (m->NewLocalOnlyQuestions) return(m->timenow); + if (m->NewLocalRecords && AnyLocalRecordReady(m)) return(m->timenow); + if (m->NewLocalOnlyRecords) return(m->timenow); + if (m->SPSProxyListChanged) return(m->timenow); + if (m->LocalRemoveEvents) return(m->timenow); + +#ifndef UNICAST_DISABLED + if (e - m->NextuDNSEvent > 0) e = m->NextuDNSEvent; + if (e - m->NextScheduledNATOp > 0) e = m->NextScheduledNATOp; + if (m->NextSRVUpdate && e - m->NextSRVUpdate > 0) e = m->NextSRVUpdate; +#endif + + if (e - m->NextCacheCheck > 0) e = m->NextCacheCheck; + if (e - m->NextScheduledSPS > 0) e = m->NextScheduledSPS; + if (e - m->NextScheduledKA > 0) e = m->NextScheduledKA; + + // NextScheduledSPRetry only valid when DelaySleep not set + if (!m->DelaySleep && m->SleepLimit && e - m->NextScheduledSPRetry > 0) e = m->NextScheduledSPRetry; + if (m->DelaySleep && e - m->DelaySleep > 0) e = m->DelaySleep; + + if (m->SuppressSending) + { + if (e - m->SuppressSending > 0) e = m->SuppressSending; + } + else + { + if (e - m->NextScheduledQuery > 0) e = m->NextScheduledQuery; + if (e - m->NextScheduledProbe > 0) e = m->NextScheduledProbe; + if (e - m->NextScheduledResponse > 0) e = m->NextScheduledResponse; + } + if (e - m->NextScheduledStopTime > 0) e = m->NextScheduledStopTime; + return(e); +} + +mDNSexport void ShowTaskSchedulingError(mDNS *const m) +{ + AuthRecord *rr; + mDNS_Lock(m); + + LogMsg("Task Scheduling Error: Continuously busy for more than a second"); + + // Note: To accurately diagnose *why* we're busy, the debugging code here needs to mirror the logic in GetNextScheduledEvent above + + if (m->NewQuestions && (!m->NewQuestions->DelayAnswering || m->timenow - m->NewQuestions->DelayAnswering >= 0)) + LogMsg("Task Scheduling Error: NewQuestion %##s (%s)", + m->NewQuestions->qname.c, DNSTypeName(m->NewQuestions->qtype)); + + if (m->NewLocalOnlyQuestions) + LogMsg("Task Scheduling Error: NewLocalOnlyQuestions %##s (%s)", + m->NewLocalOnlyQuestions->qname.c, DNSTypeName(m->NewLocalOnlyQuestions->qtype)); + + if (m->NewLocalRecords) + { + rr = AnyLocalRecordReady(m); + if (rr) LogMsg("Task Scheduling Error: NewLocalRecords %s", ARDisplayString(m, rr)); + } + + if (m->NewLocalOnlyRecords) LogMsg("Task Scheduling Error: NewLocalOnlyRecords"); + + if (m->SPSProxyListChanged) LogMsg("Task Scheduling Error: SPSProxyListChanged"); + if (m->LocalRemoveEvents) LogMsg("Task Scheduling Error: LocalRemoveEvents"); + + if (m->timenow - m->NextScheduledEvent >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledEvent %d", m->timenow - m->NextScheduledEvent); + +#ifndef UNICAST_DISABLED + if (m->timenow - m->NextuDNSEvent >= 0) + LogMsg("Task Scheduling Error: m->NextuDNSEvent %d", m->timenow - m->NextuDNSEvent); + if (m->timenow - m->NextScheduledNATOp >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledNATOp %d", m->timenow - m->NextScheduledNATOp); + if (m->NextSRVUpdate && m->timenow - m->NextSRVUpdate >= 0) + LogMsg("Task Scheduling Error: m->NextSRVUpdate %d", m->timenow - m->NextSRVUpdate); +#endif + + if (m->timenow - m->NextCacheCheck >= 0) + LogMsg("Task Scheduling Error: m->NextCacheCheck %d", m->timenow - m->NextCacheCheck); + if (m->timenow - m->NextScheduledSPS >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledSPS %d", m->timenow - m->NextScheduledSPS); + if (m->timenow - m->NextScheduledKA >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledKA %d", m->timenow - m->NextScheduledKA); + if (!m->DelaySleep && m->SleepLimit && m->timenow - m->NextScheduledSPRetry >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledSPRetry %d", m->timenow - m->NextScheduledSPRetry); + if (m->DelaySleep && m->timenow - m->DelaySleep >= 0) + LogMsg("Task Scheduling Error: m->DelaySleep %d", m->timenow - m->DelaySleep); + + if (m->SuppressSending && m->timenow - m->SuppressSending >= 0) + LogMsg("Task Scheduling Error: m->SuppressSending %d", m->timenow - m->SuppressSending); + if (m->timenow - m->NextScheduledQuery >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledQuery %d", m->timenow - m->NextScheduledQuery); + if (m->timenow - m->NextScheduledProbe >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledProbe %d", m->timenow - m->NextScheduledProbe); + if (m->timenow - m->NextScheduledResponse >= 0) + LogMsg("Task Scheduling Error: m->NextScheduledResponse %d", m->timenow - m->NextScheduledResponse); + + mDNS_Unlock(m); +} + +mDNSexport void mDNS_Unlock_(mDNS *const m, const char * const functionname) +{ + // Decrement mDNS_busy + m->mDNS_busy--; + + // Check for locking failures + if (m->mDNS_busy != m->mDNS_reentrancy) + { + LogMsg("%s: mDNS_Unlock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy); +#if ForceAlerts + *(long*)0 = 0; +#endif + } + + // If this is a final exit from the mDNSCore code, set m->NextScheduledEvent and clear m->timenow + if (m->mDNS_busy == 0) + { + m->NextScheduledEvent = GetNextScheduledEvent(m); + if (m->timenow == 0) LogMsg("%s: mDNS_Unlock: ERROR! m->timenow aready zero", functionname); + m->timenow = 0; + } + + // MUST release the platform lock LAST! + mDNSPlatformUnlock(m); +} + +// *************************************************************************** +#if COMPILER_LIKES_PRAGMA_MARK +#pragma mark - +#pragma mark - Specialized mDNS version of vsnprintf +#endif + +static const struct mDNSprintf_format +{ + unsigned leftJustify : 1; + unsigned forceSign : 1; + unsigned zeroPad : 1; + unsigned havePrecision : 1; + unsigned hSize : 1; + unsigned lSize : 1; + char altForm; + char sign; // +, - or space + unsigned int fieldWidth; + unsigned int precision; +} mDNSprintf_format_default = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; + +mDNSexport mDNSu32 mDNS_vsnprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, va_list arg) +{ + mDNSu32 nwritten = 0; + int c; + if (buflen == 0) return(0); + buflen--; // Pre-reserve one space in the buffer for the terminating null + if (buflen == 0) goto exit; + + for (c = *fmt; c != 0; c = *++fmt) + { + if (c != '%') + { + *sbuffer++ = (char)c; + if (++nwritten >= buflen) goto exit; + } + else + { + unsigned int i=0, j; + // The mDNS Vsprintf Argument Conversion Buffer is used as a temporary holding area for + // generating decimal numbers, hexdecimal numbers, IP addresses, domain name strings, etc. + // The size needs to be enough for a 256-byte domain name plus some error text. + #define mDNS_VACB_Size 300 + char mDNS_VACB[mDNS_VACB_Size]; + #define mDNS_VACB_Lim (&mDNS_VACB[mDNS_VACB_Size]) + #define mDNS_VACB_Remain(s) ((mDNSu32)(mDNS_VACB_Lim - s)) + char *s = mDNS_VACB_Lim, *digits; + struct mDNSprintf_format F = mDNSprintf_format_default; + + while (1) // decode flags + { + c = *++fmt; + if (c == '-') F.leftJustify = 1; + else if (c == '+') F.forceSign = 1; + else if (c == ' ') F.sign = ' '; + else if (c == '#') F.altForm++; + else if (c == '0') F.zeroPad = 1; + else break; + } + + if (c == '*') // decode field width + { + int f = va_arg(arg, int); + if (f < 0) { f = -f; F.leftJustify = 1; } + F.fieldWidth = (unsigned int)f; + c = *++fmt; + } + else + { + for (; c >= '0' && c <= '9'; c = *++fmt) + F.fieldWidth = (10 * F.fieldWidth) + (c - '0'); + } + + if (c == '.') // decode precision + { + if ((c = *++fmt) == '*') + { F.precision = va_arg(arg, unsigned int); c = *++fmt; } + else for (; c >= '0' && c <= '9'; c = *++fmt) + F.precision = (10 * F.precision) + (c - '0'); + F.havePrecision = 1; + } + + if (F.leftJustify) F.zeroPad = 0; + +conv: + switch (c) // perform appropriate conversion + { + unsigned long n; + case 'h': F.hSize = 1; c = *++fmt; goto conv; + case 'l': // fall through + case 'L': F.lSize = 1; c = *++fmt; goto conv; + case 'd': + case 'i': if (F.lSize) n = (unsigned long)va_arg(arg, long); + else n = (unsigned long)va_arg(arg, int); + if (F.hSize) n = (short) n; + if ((long) n < 0) { n = (unsigned long)-(long)n; F.sign = '-'; } + else if (F.forceSign) F.sign = '+'; + goto decimal; + case 'u': if (F.lSize) n = va_arg(arg, unsigned long); + else n = va_arg(arg, unsigned int); + if (F.hSize) n = (unsigned short) n; + F.sign = 0; + goto decimal; +decimal: if (!F.havePrecision) + { + if (F.zeroPad) + { + F.precision = F.fieldWidth; + if (F.sign) --F.precision; + } + if (F.precision < 1) F.precision = 1; + } + if (F.precision > mDNS_VACB_Size - 1) + F.precision = mDNS_VACB_Size - 1; + for (i = 0; n; n /= 10, i++) *--s = (char)(n % 10 + '0'); + for (; i < F.precision; i++) *--s = '0'; + if (F.sign) { *--s = F.sign; i++; } + break; + + case 'o': if (F.lSize) n = va_arg(arg, unsigned long); + else n = va_arg(arg, unsigned int); + if (F.hSize) n = (unsigned short) n; + if (!F.havePrecision) + { + if (F.zeroPad) F.precision = F.fieldWidth; + if (F.precision < 1) F.precision = 1; + } + if (F.precision > mDNS_VACB_Size - 1) + F.precision = mDNS_VACB_Size - 1; + for (i = 0; n; n /= 8, i++) *--s = (char)(n % 8 + '0'); + if (F.altForm && i && *s != '0') { *--s = '0'; i++; } + for (; i < F.precision; i++) *--s = '0'; + break; + + case 'a': { + unsigned char *a = va_arg(arg, unsigned char *); + if (!a) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; } + else + { + s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end + if (F.altForm) + { + mDNSAddr *ip = (mDNSAddr*)a; + switch (ip->type) + { + case mDNSAddrType_IPv4: F.precision = 4; a = (unsigned char *)&ip->ip.v4; break; + case mDNSAddrType_IPv6: F.precision = 16; a = (unsigned char *)&ip->ip.v6; break; + default: F.precision = 0; break; + } + } + if (F.altForm && !F.precision) + i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "«ZERO ADDRESS»"); + else switch (F.precision) + { + case 4: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%d.%d.%d.%d", + a[0], a[1], a[2], a[3]); break; + case 6: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%02X:%02X:%02X:%02X:%02X:%02X", + a[0], a[1], a[2], a[3], a[4], a[5]); break; + case 16: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), + "%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X", + a[0x0], a[0x1], a[0x2], a[0x3], a[0x4], a[0x5], a[0x6], a[0x7], + a[0x8], a[0x9], a[0xA], a[0xB], a[0xC], a[0xD], a[0xE], a[0xF]); break; + default: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%s", "<< ERROR: Must specify" + " address size (i.e. %.4a=IPv4, %.6a=Ethernet, %.16a=IPv6) >>"); break; + } + } + } + break; + + case 'p': F.havePrecision = F.lSize = 1; + F.precision = sizeof(void*) * 2; // 8 characters on 32-bit; 16 characters on 64-bit + case 'X': digits = "0123456789ABCDEF"; + goto hexadecimal; + case 'x': digits = "0123456789abcdef"; +hexadecimal: if (F.lSize) n = va_arg(arg, unsigned long); + else n = va_arg(arg, unsigned int); + if (F.hSize) n = (unsigned short) n; + if (!F.havePrecision) + { + if (F.zeroPad) + { + F.precision = F.fieldWidth; + if (F.altForm) F.precision -= 2; + } + if (F.precision < 1) F.precision = 1; + } + if (F.precision > mDNS_VACB_Size - 1) + F.precision = mDNS_VACB_Size - 1; + for (i = 0; n; n /= 16, i++) *--s = digits[n % 16]; + for (; i < F.precision; i++) *--s = '0'; + if (F.altForm) { *--s = (char)c; *--s = '0'; i += 2; } + break; + + case 'c': *--s = (char)va_arg(arg, int); i = 1; break; + + case 's': s = va_arg(arg, char *); + if (!s) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; } + else switch (F.altForm) + { + case 0: i=0; + if (!F.havePrecision) // C string + while (s[i]) i++; + else + { + while ((i < F.precision) && s[i]) i++; + // Make sure we don't truncate in the middle of a UTF-8 character + // If last character we got was any kind of UTF-8 multi-byte character, + // then see if we have to back up. + // This is not as easy as the similar checks below, because + // here we can't assume it's safe to examine the *next* byte, so we + // have to confine ourselves to working only backwards in the string. + j = i; // Record where we got to + // Now, back up until we find first non-continuation-char + while (i>0 && (s[i-1] & 0xC0) == 0x80) i--; + // Now s[i-1] is the first non-continuation-char + // and (j-i) is the number of continuation-chars we found + if (i>0 && (s[i-1] & 0xC0) == 0xC0) // If we found a start-char + { + i--; // Tentatively eliminate this start-char as well + // Now (j-i) is the number of characters we're considering eliminating. + // To be legal UTF-8, the start-char must contain (j-i) one-bits, + // followed by a zero bit. If we shift it right by (7-(j-i)) bits + // (with sign extension) then the result has to be 0xFE. + // If this is right, then we reinstate the tentatively eliminated bytes. + if (((j-i) < 7) && (((s[i] >> (7-(j-i))) & 0xFF) == 0xFE)) i = j; + } + } + break; + case 1: i = (unsigned char) *s++; break; // Pascal string + case 2: { // DNS label-sequence name + unsigned char *a = (unsigned char *)s; + s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end + if (*a == 0) *s++ = '.'; // Special case for root DNS name + while (*a) + { + char buf[63*4+1]; + if (*a > 63) + { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<INVALID LABEL LENGTH %u>>", *a); break; } + if (s + *a >= &mDNS_VACB[254]) + { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<NAME TOO LONG>>"); break; } + // Need to use ConvertDomainLabelToCString to do proper escaping here, + // so it's clear what's a literal dot and what's a label separator + ConvertDomainLabelToCString((domainlabel*)a, buf); + s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "%s.", buf); + a += 1 + *a; + } + i = (mDNSu32)(s - mDNS_VACB); + s = mDNS_VACB; // Reset s back to the start of the buffer + break; + } + } + // Make sure we don't truncate in the middle of a UTF-8 character (see similar comment below) + if (F.havePrecision && i > F.precision) + { i = F.precision; while (i>0 && (s[i] & 0xC0) == 0x80) i--;} + break; + + case 'n': s = va_arg(arg, char *); + if (F.hSize) *(short *) s = (short)nwritten; + else if (F.lSize) *(long *) s = (long)nwritten; + else *(int *) s = (int)nwritten; + continue; + + default: s = mDNS_VACB; + i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "<<UNKNOWN FORMAT CONVERSION CODE %%%c>>", c); + + case '%': *sbuffer++ = (char)c; + if (++nwritten >= buflen) goto exit; + break; + } + + if (i < F.fieldWidth && !F.leftJustify) // Pad on the left + do { + *sbuffer++ = ' '; + if (++nwritten >= buflen) goto exit; + } while (i < --F.fieldWidth); + + // Make sure we don't truncate in the middle of a UTF-8 character. + // Note: s[i] is the first eliminated character; i.e. the next character *after* the last character of the + // allowed output. If s[i] is a UTF-8 continuation character, then we've cut a unicode character in half, + // so back up 'i' until s[i] is no longer a UTF-8 continuation character. (if the input was proprly + // formed, s[i] will now be the UTF-8 start character of the multi-byte character we just eliminated). + if (i > buflen - nwritten) + { i = buflen - nwritten; while (i>0 && (s[i] & 0xC0) == 0x80) i--;} + for (j=0; j<i; j++) *sbuffer++ = *s++; // Write the converted result + nwritten += i; + if (nwritten >= buflen) goto exit; + + for (; i < F.fieldWidth; i++) // Pad on the right + { + *sbuffer++ = ' '; + if (++nwritten >= buflen) goto exit; + } + } + } +exit: + *sbuffer++ = 0; + return(nwritten); +} + +mDNSexport mDNSu32 mDNS_snprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, ...) +{ + mDNSu32 length; + + va_list ptr; + va_start(ptr,fmt); + length = mDNS_vsnprintf(sbuffer, buflen, fmt, ptr); + va_end(ptr); + + return(length); +} |