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fuchsia / third_party / mdnsresponder / e6a59006d16f8f286de6983ea6b7913ee9ada2be / . / mDNSCore / DNSCommon.c
blob: a866aa60669030e29c84838d822ee7cc161f0044 [file] [log] [blame]
/* -*- Mode: C; tab-width: 4 -*-
*
* Copyright (c) 2002-2003 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.
Change History (most recent first):
$Log: DNSCommon.c,v $
Revision 1.252 2009/06/27 00:27:03 cheshire
<rdar://problem/6959273> mDNSResponder taking up 13% CPU with 400 KBps incoming bonjour requests
Removed overly-complicate and ineffective multi-packet known-answer snooping code
(Bracketed it with "#if ENABLE_MULTI_PACKET_QUERY_SNOOPING" for now; will delete actual code later)
Revision 1.251 2009/05/19 23:40:37 cheshire
<rdar://problem/6903507> Sleep Proxy: Retransmission logic not working reliably on quiet networks
Added m->NextScheduledSPRetry timer for scheduling Sleep Proxy registration retries
Revision 1.250 2009/05/01 21:28:33 cheshire
<rdar://problem/6721680> AppleConnectAgent's reachability checks delay sleep by 30 seconds
No longer suspend network operations after we've acknowledged that the machine is going to sleep,
because other software may not have yet acknowledged the sleep event, and may be still trying
to do unicast DNS queries or other Bonjour operations.
Revision 1.249 2009/04/24 00:29:20 cheshire
<rdar://problem/3476350> Return negative answers when host knows authoritatively that no answer exists
Added support for generating/parsing/displaying NSEC records
Revision 1.248 2009/04/23 22:11:16 cheshire
Minor cleanup in debugging checks in GetLargeResourceRecord
Revision 1.247 2009/04/21 23:36:25 cheshire
<rdar://problem/6814427> Remove unused kDNSType_MAC
Revision 1.246 2009/04/21 01:00:19 cheshire
Fixed typo in previous checkin
Revision 1.245 2009/04/21 00:57:23 cheshire
<rdar://problem/6810410> Off-by-one error in putDomainNameAsLabels()
If just writing one-byte root label, make sure we have space for that
Revision 1.244 2009/04/11 00:19:30 jessic2
<rdar://problem/4426780> Daemon: Should be able to turn on LogOperation dynamically
Revision 1.243 2009/04/01 17:50:10 mcguire
cleanup mDNSRandom
Revision 1.242 2009/03/26 04:01:55 jessic2
<rdar://problem/6613786> MessageTracer: Log service types longer than 14 characters and service types with underscores
Revision 1.241 2009/03/18 20:50:08 cheshire
<rdar://problem/6650064> uDNS: Reverse lookup of own IP address takes way too long, sometimes forever
Revision 1.240 2009/03/18 20:41:04 cheshire
Added definition of the all-ones mDNSOpaque16 ID
Revision 1.239 2009/03/06 23:51:50 mcguire
Fix broken build by defining DiscardPort
Revision 1.238 2009/03/04 00:40:13 cheshire
Updated DNS server error codes to be more consistent with definitions at
<http://www.iana.org/assignments/dns-parameters>
Revision 1.237 2009/03/03 23:04:43 cheshire
For clarity, renamed "MAC" field to "HMAC" (Host MAC, as opposed to Interface MAC)
Revision 1.236 2009/03/03 22:51:53 cheshire
<rdar://problem/6504236> Sleep Proxy: Waking on same network but different interface will cause conflicts
Revision 1.235 2009/02/07 05:55:44 cheshire
Only pay attention to m->DelaySleep when it's nonzero
Revision 1.234 2009/02/07 02:52:52 cheshire
<rdar://problem/6084043> Sleep Proxy: Need to adopt IOPMConnection
Pay attention to m->DelaySleep when computing next task time
Revision 1.233 2009/01/30 23:50:31 cheshire
Added LastLabel() routine to get the last label of a domainname
Revision 1.232 2009/01/15 00:22:48 mcguire
<rdar://problem/6437092> NAT-PMP: mDNSResponder needs to listen on 224.0.0.1:5350/UDP with REUSEPORT
Revision 1.231 2008/12/12 01:24:06 cheshire
Updated GetNextScheduledEvent() to pay attention to m->SPSProxyListChanged
Revision 1.230 2008/12/10 01:55:54 cheshire
Renamed "Max" macro to avoid conflict with another "Max" macro on ARMv5
Revision 1.229 2008/11/27 01:28:45 cheshire
For display purposes, show sleep sequence number as unsigned
Revision 1.228 2008/11/26 20:57:37 cheshire
For consistency with other similar macros, renamed mdnsIsDigit/mdnsIsLetter/mdnsValidHostChar
to mDNSIsDigit/mDNSIsLetter/mDNSValidHostChar
Revision 1.227 2008/11/26 20:28:05 cheshire
Added new SSHPort constant
Revision 1.226 2008/11/16 16:55:51 cheshire
Updated debugging messages
Revision 1.225 2008/11/14 21:56:31 cheshire
Moved debugging routine ShowTaskSchedulingError() from daemon.c into DNSCommon.c
Revision 1.224 2008/11/14 02:20:03 cheshire
Include m->NextScheduledSPS in task scheduling calculations
Revision 1.223 2008/11/14 01:19:03 cheshire
Initialize TimeRcvd and TimeExpire fields in AuthRecord_struct
Revision 1.222 2008/11/14 00:00:53 cheshire
After client machine wakes up, Sleep Proxy machine need to remove any records
it was temporarily holding as proxy for that client
Revision 1.221 2008/11/13 19:06:02 cheshire
Added code to put, get, and display rdataOPT properly
Revision 1.220 2008/11/06 01:08:11 mcguire
Fix compiler warning about discarding const
Revision 1.219 2008/11/04 23:06:50 cheshire
Split RDataBody union definition into RDataBody and RDataBody2, and removed
SOA from the normal RDataBody union definition, saving 270 bytes per AuthRecord
Revision 1.218 2008/11/04 22:21:44 cheshire
Changed zone field of AuthRecord_struct from domainname to pointer, saving 252 bytes per AuthRecord
Revision 1.217 2008/11/04 22:13:43 cheshire
Made RDataBody parameter to GetRRDisplayString_rdb "const"
Revision 1.216 2008/11/04 20:06:19 cheshire
<rdar://problem/6186231> Change MAX_DOMAIN_NAME to 256
Revision 1.215 2008/10/23 23:54:35 cheshire
Added missing "const" in declaration
Revision 1.214 2008/10/23 22:25:55 cheshire
Renamed field "id" to more descriptive "updateid"
Revision 1.213 2008/10/22 01:01:52 cheshire
Added onesEthAddr constant, used for sending ARP broadcasts
Revision 1.212 2008/10/14 21:52:18 cheshire
Added support for putting/getting/printing kDNSType_MAC
Revision 1.211 2008/10/09 22:36:08 cheshire
Now that we have Sleep Proxy Server, can't suppress normal scheduling logic while going to sleep
Revision 1.210 2008/10/08 01:03:52 cheshire
Change GetFirstActiveInterface() so the NetworkInterfaceInfo it returns is not "const"
Added mDNS_SetupQuestion() convenience function
Revision 1.209 2008/09/23 04:13:30 cheshire
<rdar://problem/6238774> Remove "local" from the end of _services._dns-sd._udp PTR records
Removed old special-case Bonjour Browser hack that is no longer needed
Revision 1.208 2008/09/23 02:33:56 cheshire
<rdar://problem/4738033> uDNS: Should not compress SRV rdata in uDNS packets
Revision 1.207 2008/09/23 02:30:07 cheshire
Get rid of PutResourceRecordCappedTTL()
Revision 1.206 2008/09/23 02:26:09 cheshire
Don't need to export putEmptyResourceRecord (it's only used from DNSCommon.c)
Revision 1.205 2008/09/23 02:21:00 cheshire
Don't need to force setting of rrclass in PutResourceRecordTTLWithLimit() now that putLLQ() sets it correctly
Revision 1.204 2008/08/29 19:03:05 cheshire
<rdar://problem/6185645> Off-by-one error in putDomainNameAsLabels()
Revision 1.203 2008/08/13 00:47:53 mcguire
Handle failures when packet logging
Revision 1.202 2008/08/13 00:32:48 mcguire
refactor to use SwapDNSHeaderBytes instead of swapping manually
Revision 1.201 2008/07/24 20:23:03 cheshire
<rdar://problem/3988320> Should use randomized source ports and transaction IDs to avoid DNS cache poisoning
Revision 1.200 2008/07/18 00:07:50 cheshire
<rdar://problem/5904999> Log a message for applications that register service types longer than 14 characters
Revision 1.199 2008/03/14 19:58:38 mcguire
<rdar://problem/5500969> BTMM: Need ability to identify version of mDNSResponder client
Make sure we add the record when sending LLQ refreshes
Revision 1.198 2008/03/07 23:29:24 cheshire
Fixed cosmetic byte order display issue in DumpPacket output
Revision 1.197 2008/03/05 22:51:29 mcguire
<rdar://problem/5500969> BTMM: Need ability to identify version of mDNSResponder client
Even further refinements
Revision 1.196 2008/03/05 22:01:53 cheshire
<rdar://problem/5500969> BTMM: Need ability to identify version of mDNSResponder client
Now that we optionally add the HINFO record, when rewriting the header fields into network byte
order, we need to use our updated msg->h.numAdditionals, not the stack variable numAdditionals
Revision 1.195 2008/03/05 19:06:30 mcguire
<rdar://problem/5500969> BTMM: Need ability to identify version of mDNSResponder client
further refinements
Revision 1.194 2008/03/05 00:26:06 cheshire
<rdar://problem/5500969> BTMM: Need ability to identify version of mDNSResponder client
Revision 1.193 2007/12/17 23:42:36 cheshire
Added comments about DNSDigest_SignMessage()
Revision 1.192 2007/12/17 21:24:09 cheshire
<rdar://problem/5526800> BTMM: Need to deregister records and services on shutdown/sleep
We suspend sending of mDNS queries responses when going to sleep, so calculate GetNextScheduledEvent() time accordingly
Revision 1.191 2007/12/14 00:59:36 cheshire
<rdar://problem/5526800> BTMM: Need to deregister records and services on shutdown/sleep
While going to sleep, don't block event scheduling
Revision 1.190 2007/12/13 20:20:17 cheshire
Minor efficiency tweaks -- converted IdenticalResourceRecord, IdenticalSameNameRecord, and
SameRData from functions to macros, which allows the code to be inlined (the compiler can't
inline a function defined in a different compilation unit) and therefore optimized better.
Revision 1.189 2007/12/13 00:17:32 cheshire
RDataHashValue was not calculating hash value reliably for RDATA types that have 'holes' in the
in-memory representation (particularly SOA was affected by this, resulting in multiple duplicate
cache entities for the same SOA record, because they had erroneously different rdatahash values).
Revision 1.188 2007/12/13 00:13:03 cheshire
Simplified RDataHashValue to take a single ResourceRecord pointer, instead of separate rdlength and RDataBody
Revision 1.187 2007/12/08 00:35:20 cheshire
<rdar://problem/5636422> Updating TXT records is too slow
m->SuppressSending should not suppress all activity, just mDNS Query/Probe/Response
Revision 1.186 2007/11/15 22:52:29 cheshire
<rdar://problem/5589039> ERROR: mDNSPlatformWriteTCP - send Broken pipe
Revision 1.185 2007/10/10 20:22:03 cheshire
Added sanity checks in mDNSSendDNSMessage -- we've seen crashes in DNSDigest_SignMessage
apparently caused by trying to sign zero-length messages
Revision 1.184 2007/10/05 17:56:07 cheshire
Move CountLabels and SkipLeadingLabels to DNSCommon.c so they're callable from other files
Revision 1.183 2007/10/02 18:33:46 cheshire
Improved GetRRDisplayString to show all constituent strings within a text record
(up to the usual MaxMsg 120-character limit)
Revision 1.182 2007/10/01 19:45:01 cheshire
<rdar://problem/5514859> BTMM: Sometimes Back to My Mac autotunnel registrations are malformed
Revision 1.181 2007/10/01 18:36:53 cheshire
Yet another fix to finally get the DumpPacket RCODE display right
Revision 1.180 2007/09/29 21:30:38 cheshire
In DumpPacket/DumpRecords, show an error line if we run out of packet data
Revision 1.179 2007/09/29 20:44:56 cheshire
Fix error in DumpPacket where it was not displaying the RCODE field properly
Revision 1.178 2007/09/27 21:11:44 cheshire
Fixed spelling mistake: ROCDE -> RCODE
Revision 1.177 2007/09/27 18:51:26 cheshire
Improved DumpPacket to use "Zone/Prerequisites/Updates" nomenclature when displaying a DNS Update packet
Revision 1.176 2007/09/27 17:53:37 cheshire
Add display of RCODE and flags in DumpPacket output
Revision 1.175 2007/09/26 22:26:40 cheshire
Also show DNS query/response ID in DumpPacket output
Revision 1.174 2007/09/26 16:36:02 cheshire
In DumpPacket output, begin header line with "-- " to make it visually stand out better
Revision 1.173 2007/09/26 00:49:46 cheshire
Improve packet logging to show sent and received packets,
transport protocol (UDP/TCP/TLS) and source/destination address:port
Revision 1.172 2007/09/21 23:14:39 cheshire
<rdar://problem/5498009> BTMM: Need to log updates and query packet contents in verbose debug mode
Changed DumpRecords to use LargeCacheRecord on the stack instead of the shared m->rec storage,
to eliminate "GetLargeResourceRecord: m->rec appears to be already in use" warnings
Revision 1.171 2007/09/21 21:12:36 cheshire
<rdar://problem/5498009> BTMM: Need to log updates and query packet contents
Revision 1.170 2007/09/07 21:16:58 cheshire
Add new symbol "NATPMPAnnouncementPort" (5350)
Revision 1.169 2007/08/30 00:31:20 cheshire
Improve "locking failure" debugging messages to show function name using __func__ macro
Revision 1.168 2007/08/28 23:58:42 cheshire
Rename HostTarget -> AutoTarget
Revision 1.167 2007/08/10 23:10:05 vazquez
<rdar://problem/5389850> mDNS: Reverse lookups of IPv6 link-local addresses always fail
Revision 1.166 2007/08/01 16:09:13 cheshire
Removed unused NATTraversalInfo substructure from AuthRecord; reduced structure sizecheck values accordingly
Revision 1.165 2007/08/01 00:04:13 cheshire
<rdar://problem/5261696> Crash in tcpKQSocketCallback
Half-open TCP connections were not being cancelled properly
Revision 1.164 2007/07/27 20:48:43 cheshire
In DumpRecords(), include record TTL in output
Revision 1.163 2007/07/16 20:10:11 vazquez
<rdar://problem/3867231> LegacyNATTraversal: Need complete rewrite
Added SSDP port number
Revision 1.162 2007/07/10 01:59:33 cheshire
<rdar://problem/3557903> Performance: Core code will not work on platforms with small stacks
Fixed GetPktLease to use shared m->rec instead of putting LargeCacheRecord on the stack
Revision 1.161 2007/07/06 18:56:26 cheshire
Check m->NextScheduledNATOp in GetNextScheduledEvent()
Revision 1.160 2007/06/29 00:06:42 vazquez
<rdar://problem/5301908> Clean up NAT state machine (necessary for 6 other fixes)
Revision 1.159 2007/06/28 21:17:17 cheshire
Rename "m->nextevent" as more informative "m->NextuDNSEvent"
Revision 1.158 2007/05/25 00:25:43 cheshire
<rdar://problem/5227737> Need to enhance putRData to output all current known types
Revision 1.157 2007/05/23 00:32:15 cheshire
Don't treat uDNS responses as an entire RRSet (kDNSRecordTypePacketUniqueMask)
when received in a truncated UDP response
Revision 1.156 2007/05/15 00:29:00 cheshire
Print «ZERO ADDRESS» for %#a with a zero mDNSAddr
Revision 1.155 2007/05/07 22:07:47 cheshire
<rdar://problem/4738025> Enhance GetLargeResourceRecord to decompress more record types
Revision 1.154 2007/05/04 20:19:53 cheshire
Improve DumpPacket() output
Revision 1.153 2007/05/01 21:46:31 cheshire
Move GetLLQOptData/GetPktLease from uDNS.c into DNSCommon.c so that dnsextd can use them
Revision 1.152 2007/04/27 19:28:01 cheshire
Any code that calls StartGetZoneData needs to keep a handle to the structure, so
it can cancel it if necessary. (First noticed as a crash in Apple Remote Desktop
-- it would start a query and then quickly cancel it, and then when
StartGetZoneData completed, it had a dangling pointer and crashed.)
Revision 1.151 2007/04/26 13:35:25 cheshire
Add kDNSType_SOA case in SameRDataBody, and a comment in GetLargeResourceRecord about why this is important
Revision 1.150 2007/04/24 00:17:33 cheshire
Made LocateLLQOptData guard against packets with bogus numAdditionals value
Revision 1.149 2007/04/23 21:43:00 cheshire
Remove debugging check
Revision 1.148 2007/04/23 04:55:29 cheshire
Add some defensive null pointer checks
Revision 1.147 2007/04/22 20:18:10 cheshire
Add comment about mDNSRandom()
Revision 1.146 2007/04/22 06:02:02 cheshire
<rdar://problem/4615977> Query should immediately return failure when no server
Revision 1.145 2007/04/20 21:17:24 cheshire
For naming consistency, kDNSRecordTypeNegative should be kDNSRecordTypePacketNegative
Revision 1.144 2007/04/19 18:02:43 cheshire
<rdar://problem/5140504> Unicast DNS response records should tagged with kDNSRecordTypePacketUnique bit
Revision 1.143 2007/04/16 21:53:49 cheshire
Improve display of negative cache entries
Revision 1.142 2007/04/05 22:55:35 cheshire
<rdar://problem/5077076> Records are ending up in Lighthouse without expiry information
Revision 1.141 2007/04/04 01:33:11 cheshire
<rdar://problem/5075200> DNSServiceAddRecord is failing to advertise NULL record
Overly defensive code was zeroing too much of the AuthRecord structure
Revision 1.140 2007/04/03 19:37:58 cheshire
Rename mDNSAddrIsv4Private() to more precise mDNSAddrIsRFC1918()
Revision 1.139 2007/04/03 19:18:39 cheshire
Use mDNSSameIPv4Address (and similar) instead of accessing internal fields directly
Revision 1.138 2007/03/28 21:14:08 cheshire
The rrclass field of an OPT pseudo-RR holds the sender's UDP payload size
Revision 1.137 2007/03/28 20:59:26 cheshire
<rdar://problem/4743285> Remove inappropriate use of IsPrivateV4Addr()
Revision 1.136 2007/03/28 15:56:37 cheshire
<rdar://problem/5085774> Add listing of NAT port mapping and GetAddrInfo requests in SIGINFO output
Revision 1.135 2007/03/28 01:20:05 cheshire
<rdar://problem/4883206> Improve/create logging for secure browse
Revision 1.134 2007/03/27 23:25:35 cheshire
Fix error caching SOA records
(cache entry was size of wire-format packed data, not size of in-memory structure)
Revision 1.133 2007/03/26 22:55:45 cheshire
Add OPT and TSIG to list of types DNSTypeName() knows about
Revision 1.132 2007/03/22 18:31:48 cheshire
Put dst parameter first in mDNSPlatformStrCopy/mDNSPlatformMemCopy, like conventional Posix strcpy/memcpy
Revision 1.131 2007/03/21 21:55:20 cheshire
<rdar://problem/5069688> Hostname gets ; or : which are illegal characters
Error in AppendLabelSuffix() for numbers close to the 32-bit limit
Revision 1.130 2007/03/21 19:23:37 cheshire
<rdar://problem/5076826> jmDNS advertised garbage that shows up weird in Safari
Make check less strict so we don't break Bonjour Browser
Revision 1.129 2007/03/21 01:00:45 cheshire
<rdar://problem/5076826> jmDNS advertised garbage that shows up weird in Safari
DeconstructServiceName() needs to be more defensive about what it considers legal
Revision 1.128 2007/03/21 00:30:02 cheshire
<rdar://problem/4789455> Multiple errors in DNameList-related code
Revision 1.127 2007/03/20 17:07:15 cheshire
Rename "struct uDNS_TCPSocket_struct" to "TCPSocket", "struct uDNS_UDPSocket_struct" to "UDPSocket"
Revision 1.126 2007/03/10 03:26:44 cheshire
<rdar://problem/4961667> uDNS: LLQ refresh response packet causes cached records to be removed from cache
Revision 1.125 2007/03/07 00:08:58 cheshire
<rdar://problem/4347550> Don't allow hyphens at start of service type
Revision 1.124 2007/01/19 18:04:05 cheshire
For naming consistency, use capital letters for RR types: rdataOpt should be rdataOPT
Revision 1.123 2007/01/10 22:45:51 cheshire
Cast static strings to "(const domainname*)", not "(domainname*)"
Revision 1.122 2007/01/06 00:47:35 cheshire
Improve GetRRDisplayString to indicate when record has zero-length rdata
Revision 1.121 2007/01/05 08:30:39 cheshire
Trim excessive "$Log" checkin history from before 2006
(checkin history still available via "cvs log ..." of course)
Revision 1.120 2007/01/05 05:23:00 cheshire
Zero DNSQuestion structure in getQuestion (specifically, need TargetQID to be zero'd)
Revision 1.119 2007/01/05 04:30:16 cheshire
Change a couple of "(domainname *)" casts to "(const domainname *)"
Revision 1.118 2007/01/04 20:21:59 cheshire
<rdar://problem/4720673> uDNS: Need to start caching unicast records
Don't return multicast answers in response to unicast questions
Revision 1.117 2006/12/22 20:59:49 cheshire
<rdar://problem/4742742> Read *all* DNS keys from keychain,
not just key for the system-wide default registration domain
Revision 1.116 2006/12/21 00:04:07 cheshire
To be defensive, put a mDNSPlatformMemZero() at the start of mDNS_SetupResourceRecord()
Revision 1.115 2006/12/20 04:07:34 cheshire
Remove uDNS_info substructure from AuthRecord_struct
Revision 1.114 2006/12/19 22:40:04 cheshire
Fix compiler warnings
Revision 1.113 2006/12/19 02:21:08 cheshire
Delete spurious spaces
Revision 1.112 2006/12/15 20:42:10 cheshire
<rdar://problem/4769083> ValidateRData() should be stricter about malformed MX and SRV records
Additional defensive coding in GetLargeResourceRecord() to reject apparently-valid
rdata that actually runs past the end of the received packet data.
Revision 1.111 2006/12/15 19:09:57 cheshire
<rdar://problem/4769083> ValidateRData() should be stricter about malformed MX and SRV records
Made DomainNameLength() more defensive by adding a limit parameter, so it can be
safely used to inspect potentially malformed data received from external sources.
Without this, a domain name that starts off apparently valid, but extends beyond the end of
the received packet data, could have appeared valid if the random bytes are already in memory
beyond the end of the packet just happened to have reasonable values (e.g. all zeroes).
Revision 1.110 2006/11/18 05:01:30 cheshire
Preliminary support for unifying the uDNS and mDNS code,
including caching of uDNS answers
Revision 1.109 2006/11/10 00:54:14 cheshire
<rdar://problem/4816598> Changing case of Computer Name doesn't work
Revision 1.108 2006/10/05 23:11:18 cheshire
<rdar://problem/4769083> ValidateRData() should be stricter about malformed MX and SRV records
Revision 1.107 2006/09/15 21:20:14 cheshire
Remove uDNS_info substructure from mDNS_struct
Revision 1.106 2006/08/14 23:24:22 cheshire
Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
Revision 1.105 2006/07/15 02:01:28 cheshire
<rdar://problem/4472014> Add Private DNS client functionality to mDNSResponder
Fix broken "empty string" browsing
Revision 1.104 2006/07/05 23:09:13 cheshire
<rdar://problem/4472014> Add Private DNS client functionality to mDNSResponder
Update mDNSSendDNSMessage() to use uDNS_TCPSocket type instead of "int"
Revision 1.103 2006/06/29 07:42:14 cheshire
<rdar://problem/3922989> Performance: Remove unnecessary SameDomainName() checks
Revision 1.102 2006/06/22 19:49:11 cheshire
Added (commented out) definitions for the LLMNR UDP port and multicast addresses
Revision 1.101 2006/06/15 21:35:15 cheshire
Move definitions of mDNS_vsnprintf, mDNS_SetupResourceRecord, and some constants
from mDNS.c to DNSCommon.c, so they can be accessed from dnsextd code
Revision 1.100 2006/06/08 22:58:46 cheshire
<rdar://problem/4335605> IPv6 link-local address prefix is FE80::/10, not FE80::/16
Revision 1.99 2006/05/18 01:32:33 cheshire
<rdar://problem/4472706> iChat: Lost connection with Bonjour
(mDNSResponder insufficiently defensive against malformed browsing PTR responses)
Revision 1.98 2006/03/19 17:00:58 cheshire
Define symbol MaxMsg instead of using hard-coded constant value '80'
Revision 1.97 2006/03/18 21:47:56 cheshire
<rdar://problem/4073825> Improve logic for delaying packets after repeated interface transitions
Revision 1.96 2006/03/10 21:51:42 cheshire
<rdar://problem/4111464> After record update, old record sometimes remains in cache
Split out SameRDataBody() into a separate routine so it can be called from other code
Revision 1.95 2006/03/08 22:43:11 cheshire
Use "localdomain" symbol instead of literal string
Revision 1.94 2006/03/02 21:59:55 cheshire
<rdar://problem/4395331> Spurious warning "GetLargeResourceRecord: m->rec appears to be already in use"
Improve sanity checks & debugging support in GetLargeResourceRecord()
Revision 1.93 2006/03/02 20:30:47 cheshire
Improved GetRRDisplayString to also show priority, weight, and port for SRV records
*/
// Set mDNS_InstantiateInlines to tell mDNSEmbeddedAPI.h to instantiate inline functions, if necessary
#define mDNS_InstantiateInlines 1
#include "DNSCommon.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 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 mDNSAddr zeroAddr = { mDNSAddrType_None, {{{ 0 }}} };
mDNSexport const mDNSEthAddr onesEthAddr = { { 255, 255, 255, 255, 255, 255 } };
mDNSexport const OwnerOptData zeroOwner = { 0, 0, { { 0 } }, { { 0 } }, { { 0 } } };
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;
// 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 mDNSv4Addr AllDNSAdminGroup = { { 239, 255, 255, 251 } };
mDNSexport const mDNSv4Addr AllSystemsMcast = { { 224, 0, 0, 1 } }; // For NAT-PMP Annoucements
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 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(mDNSv4Addr *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 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_TSIG: return("TSIG");
case kDNSQType_ANY: return("ANY");
default: {
static char buffer[16];
mDNS_snprintf(buffer, sizeof(buffer), "(%d)", rrtype);
return(buffer);
}
}
}
// 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;
default:
length += mDNS_snprintf(buffer+length, RemSpc, " Unknown %d", opt->opt);
break;
}
}
}
break;
case kDNSType_NSEC: {
int i;
for (i=0; i<255; i++)
if (rd->nsec.bitmap[i>>3] & (128 >> (i&7)))
length += mDNS_snprintf(buffer+length, RemSpc, "%s ", DNSTypeName(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] = "\x04_sub";
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 > 15)
{
LogMsg("Bad service type in %#s.%##s%##s Application protocol name must be underscore plus 1-14 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 > 15 && !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);
}
// 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, mDNSRecordCallback Callback, void *Context)
{
// 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.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;
// 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->UpdateServer = zeroAddr;
rr->UpdatePort = zeroIPPort;
rr->nta = mDNSNULL;
rr->tcp = mDNSNULL;
rr->OrigRData = 0;
rr->OrigRDLen = 0;
rr->InFlightRData = 0;
rr->InFlightRDLen = 0;
rr->QueuedRData = 0;
rr->QueuedRDLen = 0;
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->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->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;
switch(rr->rrtype)
{
case kDNSType_NS:
case kDNSType_CNAME:
case kDNSType_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_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: len = sizeof(rdataNSEC); // Use in-memory length of 32, and fall through default checksum computation below
default:
{
mDNSu32 sum = 0;
int i;
for (i=0; i+1 < len; i+=2)
{
sum += (((mDNSu32)(rdb->data[i])) << 8) | rdb->data[i+1];
sum = (sum<<3) | (sum>>29);
}
if (i < len)
{
sum += ((mDNSu32)(rdb->data[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)
{
const RDataBody2 *const b1 = (RDataBody2 *)r1->rdata->u.data;
const RDataBody2 *const b2 = (RDataBody2 *)r2;
switch(r1->rrtype)
{
case kDNSType_NS:
case kDNSType_CNAME:
case kDNSType_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 &&
SameDomainName(&b1->soa.mname, &b2->soa.mname) &&
SameDomainName(&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 &&
SameDomainName(&b1->mx.exchange, &b2->mx.exchange));
case kDNSType_RP: return(mDNSBool)( SameDomainName(&b1->rp.mbox, &b2->rp.mbox) &&
SameDomainName(&b1->rp.txt, &b2->rp.txt));
case kDNSType_PX: return(mDNSBool)( b1->px.preference == b2->px.preference &&
SameDomainName(&b1->px.map822, &b2->px.map822) &&
SameDomainName(&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) &&
SameDomainName(&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: return(mDNSPlatformMemSame(b1->data, b2->data, sizeof(rdataNSEC)));
default: return(mDNSPlatformMemSame(b1->data, b2->data, r1->rdlength));
}
}
// 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)
{
if (rr->InterfaceID &&
q ->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly &&
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);
// 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);
return(mDNStrue);
}
mDNSexport mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q)
{
if (rr->InterfaceID &&
q ->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly &&
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);
// 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);
return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname));
}
mDNSexport mDNSBool AnyTypeRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q)
{
if (rr->InterfaceID &&
q ->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly &&
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 (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: {
int i;
for (i=sizeof(rdataNSEC); i>0; i--) if (rd->nsec.bitmap[i-1]) break;
// 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
return((estimate ? 1 : DomainNameLength(rr->name)) + 2 + i);
}
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);
}
// msg points to the message we're building (pass mDNSNULL 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, 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;
}
}
return ptr;
}
case kDNSType_NSEC: {
// 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
int i, j;
for (i=sizeof(rdataNSEC); i>0; i--) if (rdb->nsec.bitmap[i-1]) break;
ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name);
if (!ptr) return(mDNSNULL);
if (ptr + 2 + i > limit) return(mDNSNULL);
*ptr++ = 0;
*ptr++ = i;
for (j=0; j<i; j++) *ptr++ = rdb->nsec.bitmap[j];
return ptr;
}
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("PutResourceRecord ERROR! Attempt to put kDNSRecordTypeUnregistered %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype));
return(ptr);
}
if (!ptr) { LogMsg("PutResourceRecordTTLWithLimit ptr is null"); return(mDNSNULL); }
ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name);
if (!ptr || ptr + 10 >= limit) return(mDNSNULL); // If we're out-of-space, 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);
endofrdata = putRData(rdatacompressionbase, ptr+10, limit, rr);
if (!endofrdata) { verbosedebugf("Ran out of space in PutResourceRecord for %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); 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, 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;
}
mDNSexport mDNSu8 *putDeleteRRSet(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype)
{
const mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData;
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, 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;
}
mDNSexport mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *end, DomainAuthInfo *authInfo)
{
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, 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 = PutResourceRecord(msg, end, &msg->h.numAdditionals, &hinfo.resrec);
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);
}
mDNSlocal mDNSu16 getVal16(const mDNSu8 **ptr)
{
mDNSu16 val = (mDNSu16)(((mDNSu16)(*ptr)[0]) << 8 | (*ptr)[1]);
*ptr += sizeof(mDNSOpaque16);
return val;
}
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;
RDataBody2 *const rdb = (RDataBody2 *)rr->smallrdatastorage.data;
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 SetNextCacheCheckTime()
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;
ptr = getDomainName(msg, ptr, end, &largecr->namestorage);
if (!ptr) { debugf("GetLargeResourceRecord: Malformed RR name"); return(mDNSNULL); }
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 (!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 switch (rr->resrec.rrtype)
{
case kDNSType_A: if (pktrdlength != sizeof(mDNSv4Addr)) return(mDNSNULL);
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_CNAME:
case kDNSType_PTR:
case kDNSType_DNAME:ptr = getDomainName(msg, ptr, end, &rdb->name);
if (ptr != end) { debugf("GetLargeResourceRecord: Malformed CNAME/PTR RDATA name"); return(mDNSNULL); }
//debugf("%##s PTR %##s rdlen %d", rr->resrec.name.c, rdb->name.c, pktrdlength);
break;
case kDNSType_SOA: ptr = getDomainName(msg, ptr, end, &rdb->soa.mname);
if (!ptr) { debugf("GetLargeResourceRecord: Malformed SOA RDATA mname"); return mDNSNULL; }
ptr = getDomainName(msg, ptr, end, &rdb->soa.rname);
if (!ptr) { debugf("GetLargeResourceRecord: Malformed SOA RDATA rname"); return mDNSNULL; }
if (ptr + 0x14 != end) { debugf("GetLargeResourceRecord: Malformed SOA RDATA"); return mDNSNULL; }
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_TSIG:
case kDNSType_TXT:
case kDNSType_X25:
case kDNSType_ISDN:
case kDNSType_LOC:
case kDNSType_DHCID:if (pktrdlength > rr->resrec.rdata->MaxRDLength)
{
debugf("GetLargeResourceRecord: %s rdata size (%d) exceeds storage (%d)",
DNSTypeName(rr->resrec.rrtype), pktrdlength, rr->resrec.rdata->MaxRDLength);
return(mDNSNULL);
}
rr->resrec.rdlength = pktrdlength;
mDNSPlatformMemCopy(rdb->data, ptr, pktrdlength);
break;
case kDNSType_MX:
case kDNSType_AFSDB:
case kDNSType_RT:
case kDNSType_KX: if (pktrdlength < 3) return(mDNSNULL); // Preference + domainname
rdb->mx.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]);
ptr = getDomainName(msg, ptr+2, end, &rdb->mx.exchange);
if (ptr != end) { debugf("GetLargeResourceRecord: Malformed MX name"); return(mDNSNULL); }
//debugf("%##s SRV %##s rdlen %d", rr->resrec.name.c, rdb->srv.target.c, pktrdlength);
break;
case kDNSType_RP: ptr = getDomainName(msg, ptr, end, &rdb->rp.mbox); // Domainname + domainname
if (!ptr) { debugf("GetLargeResourceRecord: Malformed RP mbox"); return mDNSNULL; }
ptr = getDomainName(msg, ptr, end, &rdb->rp.txt);
if (ptr != end) { debugf("GetLargeResourceRecord: Malformed RP txt"); return mDNSNULL; }
break;
case kDNSType_PX: if (pktrdlength < 4) return(mDNSNULL); // Preference + domainname + domainname
rdb->px.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]);
ptr = getDomainName(msg, ptr, end, &rdb->px.map822);
if (!ptr) { debugf("GetLargeResourceRecord: Malformed PX map822"); return mDNSNULL; }
ptr = getDomainName(msg, ptr, end, &rdb->px.mapx400);
if (ptr != end) { debugf("GetLargeResourceRecord: Malformed PX mapx400"); return mDNSNULL; }
break;
case kDNSType_AAAA: if (pktrdlength != sizeof(mDNSv6Addr)) return(mDNSNULL);
mDNSPlatformMemCopy(&rdb->ipv6, ptr, sizeof(rdb->ipv6));
break;
case kDNSType_SRV: if (pktrdlength < 7) return(mDNSNULL); // Priority + weight + port + domainname
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 = getDomainName(msg, ptr+6, end, &rdb->srv.target);
if (ptr != end) { debugf("GetLargeResourceRecord: Malformed SRV RDATA name"); return(mDNSNULL); }
//debugf("%##s SRV %##s rdlen %d", rr->resrec.name.c, rdb->srv.target.c, pktrdlength);
break;
case kDNSType_OPT: {
rdataOPT *opt = rr->resrec.rdata->u.opt;
rr->resrec.rdlength = 0;
while (ptr < end && (mDNSu8 *)(opt+1) < &rr->resrec.rdata->u.data[MaximumRDSize])
{
if (ptr + 4 > end) { LogMsg("GetLargeResourceRecord: OPT RDATA ptr + 4 > end"); return(mDNSNULL); }
opt->opt = getVal16(&ptr);
opt->optlen = getVal16(&ptr);
if (!ValidDNSOpt(opt)) { LogMsg("GetLargeResourceRecord: opt %d optlen %d wrong", opt->opt, opt->optlen); return(mDNSNULL); }
if (ptr + opt->optlen > end) { LogMsg("GetLargeResourceRecord: ptr + opt->optlen > end"); return(mDNSNULL); }
switch(opt->opt)
{
case kDNSOpt_LLQ:
opt->u.llq.vers = getVal16(&ptr);
opt->u.llq.llqOp = getVal16(&ptr);
opt->u.llq.err = getVal16(&ptr);
mDNSPlatformMemCopy(opt->u.llq.id.b, ptr, 8);
ptr += 8;
opt->u.llq.llqlease = (mDNSu32) ((mDNSu32)ptr[0] << 24 | (mDNSu32)ptr[1] << 16 | (mDNSu32)ptr[2] << 8 | ptr[3]);
if (opt->u.llq.llqlease > 0x70000000UL / mDNSPlatformOneSecond)
opt->u.llq.llqlease = 0x70000000UL / mDNSPlatformOneSecond;
ptr += sizeof(mDNSOpaque32);
break;
case kDNSOpt_Lease:
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;
ptr += sizeof(mDNSs32);
break;
case kDNSOpt_Owner:
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
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));
}
ptr += opt->optlen;
break;
}
opt++; // increment pointer into rdatabody
}
rr->resrec.rdlength = (mDNSu8*)opt - rr->resrec.rdata->u.data;
if (ptr != end) { LogMsg("GetLargeResourceRecord: Malformed OptRdata"); return(mDNSNULL); }
break;
}
case kDNSType_NSEC: {
unsigned int i, j;
domainname d;
ptr = getDomainName(msg, ptr, end, &d); // Ignored for our simplified use of NSEC synthetic records
if (!ptr) { debugf("GetLargeResourceRecord: Malformed NSEC nextname"); return mDNSNULL; }
if (*ptr++ != 0) { debugf("GetLargeResourceRecord: We only handle block zero NSECs"); return mDNSNULL; }
i = *ptr++;
if (i < 1 || i > sizeof(rdataNSEC)) { debugf("GetLargeResourceRecord: invalid block length %d", i); return mDNSNULL; }
mDNSPlatformMemZero(rdb->nsec.bitmap, sizeof(rdb->nsec.bitmap));
for (j=0; j<i; j++) rdb->nsec.bitmap[j] = *ptr++;
if (ptr != end) { LogMsg("GetLargeResourceRecord: Malformed NSEC"); return(mDNSNULL); }
break;
}
default: if (pktrdlength > rr->resrec.rdata->MaxRDLength)
{
debugf("GetLargeResourceRecord: rdata %d (%s) size (%d) exceeds storage (%d)",
rr->resrec.rrtype, DNSTypeName(rr->resrec.rrtype), pktrdlength, rr->resrec.rdata->MaxRDLength);
return(mDNSNULL);
}
debugf("GetLargeResourceRecord: 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 = pktrdlength;
mDNSPlatformMemCopy(rdb->data, ptr, pktrdlength);
break;
}
rr->resrec.namehash = DomainNameHashValue(rr->resrec.name);
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);
}
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) 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("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" : "Receiv")] = 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)
{
mStatus status = mStatus_NoError;
const mDNSu16 numAdditionals = msg->h.numAdditionals;
mDNSu8 *newend;
// 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);
if (!newend) LogMsg("mDNSSendDNSMessage: putHINFO failed"); // 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);
else
{
mDNSu16 msglen = (mDNSu16)(end - (mDNSu8 *)msg);
mDNSu8 lenbuf[2] = { (mDNSu8)(msglen >> 8), (mDNSu8)(msglen & 0xFF) };
long nsent = mDNSPlatformWriteTCP(sock, (char*)lenbuf, 2); // Should do scatter/gather here -- this is probably going out as two packets
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)
{
// 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 ForceAlerts
if (m->mDNS_busy != m->mDNS_reentrancy)
{
LogMsg("mDNS_Lock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", m->mDNS_busy, m->mDNS_reentrancy);
*(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("mDNS_Lock: m->timenow already set (%ld/%ld)", 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("mDNS_Lock: m->mDNS_busy is %ld but m->timenow not set", 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("mDNSPlatformRawTime went backwards by %ld ticks; setting correction factor to %ld", 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 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 && LocalRecordReady(m->NewLocalRecords)) return(m->timenow);
if (m->SPSProxyListChanged) return(m->timenow);
#ifndef UNICAST_DISABLED
if (e - m->NextuDNSEvent > 0) e = m->NextuDNSEvent;
if (e - m->NextScheduledNATOp > 0) e = m->NextScheduledNATOp;
#endif
if (e - m->NextCacheCheck > 0) e = m->NextCacheCheck;
if (e - m->NextScheduledSPS > 0) e = m->NextScheduledSPS;
// 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;
}
return(e);
}
mDNSexport void ShowTaskSchedulingError(mDNS *const m)
{
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 && LocalRecordReady(m->NewLocalRecords))
LogMsg("Task Scheduling Error: NewLocalRecords %s", ARDisplayString(m, m->NewLocalRecords));
if (m->timenow - m->NextScheduledEvent >= 0)
LogMsg("Task Scheduling Error: m->NextScheduledEvent %d", m->timenow - m->NextScheduledEvent);
if (m->SuppressSending && m->timenow - m->SuppressSending >= 0)
LogMsg("Task Scheduling Error: m->SuppressSending %d", m->timenow - m->SuppressSending);
if (m->timenow - m->NextCacheCheck >= 0)
LogMsg("Task Scheduling Error: m->NextCacheCheck %d", m->timenow - m->NextCacheCheck);
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);
if (m->timenow - m->NextScheduledNATOp >= 0)
LogMsg("Task Scheduling Error: m->NextScheduledNATOp %d", m->timenow - m->NextScheduledNATOp);
if (m->timenow - m->NextScheduledSPS >= 0)
LogMsg("Task Scheduling Error: m->NextScheduledSPS %d", m->timenow - m->NextScheduledSPS);
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);
#ifndef UNICAST_DISABLED
if (m->timenow - m->NextuDNSEvent >= 0)
LogMsg("Task Scheduling Error: NextuDNSEvent %d", m->timenow - m->NextuDNSEvent);
#endif
mDNS_Unlock(m);
}
mDNSexport void mDNS_Unlock_(mDNS *const m)
{
// Decrement mDNS_busy
m->mDNS_busy--;
// Check for locking failures
#if ForceAlerts
if (m->mDNS_busy != m->mDNS_reentrancy)
{
LogMsg("mDNS_Unlock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", m->mDNS_busy, m->mDNS_reentrancy);
*(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("mDNS_Unlock: ERROR! m->timenow aready zero");
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 = 8;
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);
}