2552 lines
56 KiB
C
2552 lines
56 KiB
C
/*++
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Copyright (c) 1996-2000 Microsoft Corporation
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Module Name:
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packet.c
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Abstract:
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Domain Name System (DNS) Library
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Packet writing utilities.
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Author:
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|
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Jim Gilroy (jamesg) October, 1996
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Environment:
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User Mode - Win32
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Revision History:
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--*/
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#include "local.h"
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//
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// Global XID counter, to generate unique XIDs
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//
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WORD gwTransactionId = 1;
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//
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// Class values for UPDATE packets
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// (Key concept here -- designed by committee)
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//
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// These arrays are indexed by
|
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// !wDataLength -- row
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// Delete flag -- column
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//
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WORD PrereqClassArray[2][2] =
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{
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DNS_RCLASS_INTERNET, // data != 0, no delete
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0, // data != 0, delete => ERROR
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DNS_RCLASS_ANY, // no data, no delete
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DNS_RCLASS_NONE, // no data, delete
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};
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WORD UpdateClassArray[2][2] =
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{
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DNS_RCLASS_INTERNET, // data != 0, no delete
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DNS_RCLASS_NONE, // data != 0, delete
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0, // no data, no delete => ERROR
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DNS_RCLASS_ANY, // no data, delete
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};
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PDNS_MSG_BUF
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Dns_AllocateMsgBuf(
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IN WORD wBufferLength OPTIONAL
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)
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/*++
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Routine Description:
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Allocate message buffer.
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Arguments:
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wBufferLength - optional length of message buffer; default is MAX
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UDP size
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Return Value:
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Ptr to message buffer.
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NULL on error.
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--*/
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{
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PDNS_MSG_BUF pmsg;
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BOOL ftcp = FALSE;
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//
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// default allocation to UDP max buffer length
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//
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if ( wBufferLength <= DNS_MAX_UDP_PACKET_BUFFER_LENGTH )
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{
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wBufferLength = DNS_MAX_UDP_PACKET_BUFFER_LENGTH;
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}
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else
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{
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ftcp = TRUE;
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}
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pmsg = ALLOCATE_HEAP( SIZEOF_MSG_BUF_OVERHEAD + wBufferLength );
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if ( pmsg == NULL )
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{
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return( NULL );
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}
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pmsg->BufferLength = wBufferLength;
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//
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// limit UDP sends to classical RFC UDP limit (512 bytes)
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// write routines use pBufferEnd to determine writeability
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//
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if ( !ftcp )
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{
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wBufferLength = DNS_RFC_MAX_UDP_PACKET_LENGTH;
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}
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pmsg->pBufferEnd = (PCHAR)&pmsg->MessageHead + wBufferLength;
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pmsg->fTcp = (BOOLEAN)ftcp;
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Dns_InitializeMsgBuf( pmsg );
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return( pmsg );
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}
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VOID
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Dns_InitializeMsgBuf(
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IN OUT PDNS_MSG_BUF pMsg
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)
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/*++
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Routine Description:
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Allocate message buffer.
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Arguments:
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wBufferLength - optional length of message buffer; default is MAX
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UDP size
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Return Value:
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Ptr to message buffer.
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NULL on error.
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--*/
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{
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// setup addressing info
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pMsg->Socket = 0;
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pMsg->RemoteAddressLength = sizeof(SOCKADDR_IN);
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// set for packet reception
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if ( pMsg->fTcp )
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{
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SET_MESSAGE_FOR_TCP_RECV( pMsg );
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}
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else
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{
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SET_MESSAGE_FOR_UDP_RECV( pMsg );
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}
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// clear header
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RtlZeroMemory(
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&pMsg->MessageHead,
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sizeof( DNS_HEADER ) );
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// set for rewriting
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pMsg->pCurrent = pMsg->MessageBody;
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}
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//
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// Writing to packet
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//
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PCHAR
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_fastcall
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Dns_WriteDottedNameToPacket(
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IN OUT PCHAR pch,
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IN PCHAR pchStop,
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IN LPSTR pszName,
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IN LPSTR pszDomain, OPTIONAL
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IN WORD wDomainOffset, OPTIONAL
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IN BOOL fUnicodeName
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)
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/*++
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Routine Description:
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Write lookup name to packet.
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Arguments:
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pch -- ptr to current position in packet buffer
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pchStop -- end of packet buffer
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pszName - dotted FQDN to write
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pszDomain - domain name already in packet (OPTIONAL); note this is
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a fragment of the SAME STRING as pszName; i.e. ptr compare
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NOT strcmp is done to determine if at domain name
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wDomainOffset - offset in packet of domain name; MUST include this
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if pszDomain is given
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fUnicodeName -- pszName is unicode string
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TRUE -- name is unicode
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FALSE -- name is UTF8
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Return Value:
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Ptr to next position in packet buffer.
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NULL on error.
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--*/
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{
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CHAR ch;
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PCHAR pchlabelStart;
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UCHAR countLabel = 0;
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ULONG countName = 0;
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CHAR nameBuffer[ DNS_MAX_NAME_BUFFER_LENGTH ];
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WCHAR nameWideBuffer[ DNS_MAX_NAME_BUFFER_LENGTH ];
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// protect message buffer overrun
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if ( pch >= pchStop )
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{
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return( NULL );
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}
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// allow root to be indicated by NULL
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if ( !pszName )
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{
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*pch++ = 0;
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return( pch );
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}
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//
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// protect stack buffers from bogus names
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//
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if ( fUnicodeName )
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{
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countName = wcslen( (LPWSTR) pszName );
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}
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else
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{
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countName = strlen( pszName );
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}
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if ( countName >= DNS_MAX_NAME_BUFFER_LENGTH )
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{
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return NULL;
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}
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countName = 0;
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//
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// UTF8 name with extended chars?
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// - then must go up to unicode for downcasing
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//
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if ( !fUnicodeName )
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{
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if ( !Dns_IsStringAscii( pszName ) )
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{
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DWORD bufLength = DNS_MAX_NAME_BUFFER_LENGTH_UNICODE;
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if ( ! Dns_NameCopy(
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(PCHAR) nameWideBuffer,
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& bufLength,
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pszName,
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0, // length unknown
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DnsCharSetUtf8,
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DnsCharSetUnicode
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) )
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{
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return( NULL );
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}
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pszName = (PCHAR) nameWideBuffer;
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fUnicodeName = TRUE;
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}
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}
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//
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// convert unicode name to UTF8
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// - if extended chars, then downcase before hit the wire
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//
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if ( fUnicodeName )
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{
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if ( !Dns_IsWideStringAscii( (PWSTR)pszName ) )
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{
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Dns_DownCaseBuffW(
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(PWCHAR) pszName,
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0 );
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}
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if ( ! Dns_NameCopy(
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nameBuffer,
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NULL, // assume adequate length
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pszName,
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0, // length unknown
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DnsCharSetUnicode,
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DnsCharSetUtf8
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) )
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{
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return( NULL );
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}
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pszName = nameBuffer;
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}
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//
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// special case "." root name
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// - allows us to fail all other zero length labels cleanly
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//
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if ( *pszName == '.' )
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{
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||
if ( *(pszName+1) != 0 )
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{
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return( NULL );
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}
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*pch++ = 0;
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return( pch );
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||
}
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//
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||
// write lookup name
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// - leave
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||
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||
pchlabelStart = pch++;
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while( ch = *pszName++ )
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||
{
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||
// out of space
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||
|
||
if ( pch >= pchStop )
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||
{
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||
return( NULL );
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||
}
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||
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||
// not at end of label -- just copy character
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||
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||
if ( ch != '.' )
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{
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*pch++ = ch;
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countLabel++;
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countName++;
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continue;
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||
}
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||
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//
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||
// at end of label
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// - write label count
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||
// - reset counter
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||
// - if reached domain name, write compression and quit
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||
//
|
||
|
||
if ( countLabel > DNS_MAX_LABEL_LENGTH ||
|
||
countLabel == 0 ||
|
||
countName > DNS_MAX_NAME_LENGTH )
|
||
{
|
||
return( NULL );
|
||
}
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||
*pchlabelStart = countLabel;
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countLabel = 0;
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countName++;
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pchlabelStart = pch++;
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if ( pszName == pszDomain )
|
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{
|
||
if ( ++pch >= pchStop )
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{
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return( NULL );
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}
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*(UNALIGNED WORD *)pchlabelStart =
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htons( (WORD)(wDomainOffset | (WORD)0xC000) );
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||
return( pch );
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}
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}
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||
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if ( countLabel > DNS_MAX_LABEL_LENGTH ||
|
||
countName > DNS_MAX_NAME_LENGTH )
|
||
{
|
||
return( NULL );
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||
}
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||
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||
//
|
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// NULL terminate
|
||
// - if no terminating ".", do end of label processing also
|
||
// - return ptr to char after terminating NULL
|
||
|
||
if ( countLabel )
|
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{
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||
*pchlabelStart = countLabel;
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*pch++ = 0;
|
||
}
|
||
else
|
||
{
|
||
DNS_ASSERT( pch == pchlabelStart + 1 );
|
||
*pchlabelStart = 0;
|
||
}
|
||
return( pch );
|
||
}
|
||
|
||
|
||
|
||
PCHAR
|
||
_fastcall
|
||
Dns_WriteStringToPacket(
|
||
IN OUT PCHAR pch,
|
||
IN PCHAR pchStop,
|
||
IN LPSTR pszString,
|
||
IN BOOL fUnicodeString
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Write string to packet.
|
||
|
||
Arguments:
|
||
|
||
pch -- ptr to current position in packet buffer
|
||
|
||
pchStop -- end of packet buffer
|
||
|
||
pszString - string to write
|
||
|
||
fUnicodeString -- pszString is unicode string
|
||
|
||
Return Value:
|
||
|
||
Ptr to next position in packet buffer.
|
||
NULL on error.
|
||
|
||
--*/
|
||
{
|
||
DWORD length;
|
||
|
||
//
|
||
// handle NULL string
|
||
//
|
||
|
||
if ( !pszString )
|
||
{
|
||
if ( pch >= pchStop )
|
||
{
|
||
return( NULL );
|
||
}
|
||
*pch++ = 0;
|
||
return( pch );
|
||
}
|
||
|
||
//
|
||
// get string length
|
||
// - get required buf length, then whack whack off space
|
||
// for terminating NULL
|
||
// - zero error case, becomes very large number and is
|
||
// caught by length>MAXCHAR test
|
||
//
|
||
|
||
length = Dns_GetBufferLengthForStringCopy(
|
||
pszString,
|
||
0,
|
||
fUnicodeString ? DnsCharSetUnicode : DnsCharSetUtf8,
|
||
DnsCharSetUtf8 );
|
||
length--;
|
||
|
||
//
|
||
// set length byte
|
||
//
|
||
|
||
if ( length > MAXUCHAR )
|
||
{
|
||
SetLastError( ERROR_INVALID_DATA );
|
||
return( NULL );
|
||
}
|
||
*pch++ = (UCHAR) length;
|
||
|
||
if ( pch + length > pchStop )
|
||
{
|
||
SetLastError( ERROR_MORE_DATA );
|
||
return( NULL );
|
||
}
|
||
|
||
//
|
||
// copy string
|
||
//
|
||
// note unicode conversion will write NULL terminator, so
|
||
// test again for space in packet
|
||
//
|
||
|
||
if ( fUnicodeString )
|
||
{
|
||
if ( pch + length + 1 > pchStop )
|
||
{
|
||
SetLastError( ERROR_MORE_DATA );
|
||
return( NULL );
|
||
}
|
||
Dns_StringCopy(
|
||
pch,
|
||
NULL,
|
||
pszString,
|
||
length,
|
||
DnsCharSetUnicode,
|
||
DnsCharSetUtf8 );
|
||
}
|
||
else
|
||
{
|
||
memcpy(
|
||
pch,
|
||
pszString,
|
||
length );
|
||
}
|
||
|
||
return( pch+length );
|
||
}
|
||
|
||
|
||
|
||
PCHAR
|
||
Dns_WriteQuestionToMessage(
|
||
IN OUT PDNS_MSG_BUF pMsg,
|
||
IN PDNS_NAME pszName,
|
||
IN WORD wType,
|
||
IN BOOL fUnicodeName
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Write question to packet.
|
||
|
||
Note: Routine DOES NOT clear message info or message header.
|
||
This is optimized for use immediately following Dns_CreateMessage().
|
||
|
||
Arguments:
|
||
|
||
pMsg - message info
|
||
|
||
pszName - DNS name of question
|
||
|
||
wType - question type
|
||
|
||
fUnicodeName - name is in unicode
|
||
|
||
Return Value:
|
||
|
||
Ptr to next char in buffer, if successful.
|
||
NULL if error writing question name.
|
||
|
||
--*/
|
||
{
|
||
PCHAR pch;
|
||
|
||
// use recursion, as default
|
||
|
||
pMsg->MessageHead.RecursionDesired = TRUE;
|
||
|
||
// restart write at message header
|
||
|
||
pch = pMsg->MessageBody;
|
||
|
||
// write question name
|
||
|
||
pch = Dns_WriteDottedNameToPacket(
|
||
pch,
|
||
pMsg->pBufferEnd,
|
||
pszName,
|
||
NULL,
|
||
0,
|
||
fUnicodeName );
|
||
if ( !pch )
|
||
{
|
||
return( NULL );
|
||
}
|
||
|
||
// write question structure
|
||
|
||
*(UNALIGNED WORD *) pch = htons( wType );
|
||
pch += sizeof(WORD);
|
||
*(UNALIGNED WORD *) pch = DNS_RCLASS_INTERNET;
|
||
pch += sizeof(WORD);
|
||
|
||
// set question RR section count
|
||
|
||
pMsg->MessageHead.QuestionCount = 1;
|
||
|
||
// header fields in host order
|
||
|
||
pMsg->fSwapped = FALSE;
|
||
|
||
// reset current ptr
|
||
|
||
pMsg->pCurrent = pch;
|
||
|
||
IF_DNSDBG( INIT )
|
||
{
|
||
DnsDbg_Message(
|
||
"Packet after question write:",
|
||
pMsg );
|
||
}
|
||
return( pch );
|
||
}
|
||
|
||
|
||
|
||
DNS_STATUS
|
||
Dns_WriteRecordStructureToMessage(
|
||
IN OUT PDNS_MSG_BUF pMsg,
|
||
IN WORD wType,
|
||
IN WORD wClass,
|
||
IN DWORD dwTtl,
|
||
IN WORD wDataLength
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
No data RR cases:
|
||
|
||
This includes prereqs and deletes except for specific record cases.
|
||
|
||
Arguments:
|
||
|
||
pch - ptr to next byte in packet buffer
|
||
|
||
pchStop - end of packet buffer
|
||
|
||
wClass - class
|
||
|
||
wType - desired RR type
|
||
|
||
dwTtl - time to live
|
||
|
||
wDataLength - data length
|
||
|
||
Return Value:
|
||
|
||
Ptr to next postion in buffer, if successful.
|
||
NULL on error.
|
||
|
||
--*/
|
||
{
|
||
PDNS_WIRE_RECORD pdnsRR;
|
||
PCHAR pchdata;
|
||
|
||
IF_DNSDBG( WRITE2 )
|
||
{
|
||
DNS_PRINT(( "Dns_WriteRecordStructureToMessage(%p).\n", pMsg ));
|
||
}
|
||
|
||
//
|
||
// out of space
|
||
//
|
||
|
||
pdnsRR = (PDNS_WIRE_RECORD) pMsg->pCurrent;
|
||
pchdata = (PCHAR) pdnsRR + sizeof( DNS_WIRE_RECORD );
|
||
|
||
if ( pchdata + wDataLength >= pMsg->pBufferEnd )
|
||
{
|
||
DNS_PRINT(( "ERROR out of space writing record to packet.\n" ));
|
||
return( ERROR_MORE_DATA );
|
||
}
|
||
|
||
//
|
||
// write RR wire structure
|
||
//
|
||
|
||
*(UNALIGNED WORD *) &pdnsRR->RecordType = htons( wType );
|
||
*(UNALIGNED WORD *) &pdnsRR->RecordClass = htons( wClass );
|
||
*(UNALIGNED DWORD *) &pdnsRR->TimeToLive = htonl( dwTtl );
|
||
*(UNALIGNED WORD *) &pdnsRR->DataLength = htons( wDataLength );
|
||
|
||
//
|
||
// update current ptr
|
||
//
|
||
|
||
pMsg->pCurrent = pchdata;
|
||
|
||
return( ERROR_SUCCESS );
|
||
}
|
||
|
||
|
||
|
||
#if 0
|
||
DNS_STATUS
|
||
Dns_WriteOptToMessage(
|
||
IN OUT PDNS_MSG_BUF pMsg,
|
||
IN WORD wPayload
|
||
IN DWORD Rcode,
|
||
IN BYTE Version,
|
||
IN PBYTE pData,
|
||
IN WORD wDataLength
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Write OPT record to message.
|
||
|
||
Arguments:
|
||
|
||
pMsg -- message
|
||
|
||
wPayload -- max length client can receive in UDP
|
||
|
||
Rcode -- RCODE, if extended some of this ends up in OPT
|
||
|
||
Version -- EDNS version
|
||
|
||
pData -- ptr to data buffer of OPT data
|
||
|
||
wDataLength -- length of pData
|
||
|
||
Return Value:
|
||
|
||
ERROR_SUCCESS if successfully writen.
|
||
ErrorCode on failure.
|
||
|
||
--*/
|
||
{
|
||
}
|
||
#endif
|
||
|
||
|
||
|
||
DNS_STATUS
|
||
Dns_WriteRecordStructureToPacket(
|
||
IN OUT PCHAR pchBuf,
|
||
IN PDNS_RECORD pRecord,
|
||
IN BOOL fUpdatePacket
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Write wire record structure for given record.
|
||
|
||
Arguments:
|
||
|
||
pchBuf - ptr to next byte in packet buffer
|
||
|
||
pRecord - record to write
|
||
|
||
fUpdatePacket -- If TRUE, the packet is going to contain an update.
|
||
Therefore the section flags in the pRecords
|
||
should be interpreted for update. Otherwise this is
|
||
for a query and section flags will be interpreted for
|
||
query.
|
||
|
||
Return Value:
|
||
|
||
None
|
||
|
||
--*/
|
||
{
|
||
PDNS_WIRE_RECORD pwireRecord;
|
||
WORD class;
|
||
DWORD ttl;
|
||
|
||
IF_DNSDBG( WRITE2 )
|
||
{
|
||
DNS_PRINT((
|
||
"Writing RR struct (%p) to packet buffer at %p.\n",
|
||
pRecord,
|
||
pchBuf
|
||
));
|
||
DnsDbg_Record(
|
||
"Record being written:",
|
||
pRecord );
|
||
}
|
||
|
||
//
|
||
// get TTL, it will be set to zero for several of the update cases
|
||
//
|
||
|
||
ttl = pRecord->dwTtl;
|
||
|
||
//
|
||
// determine class
|
||
// - class variable is in net order (for perf)
|
||
// - default is class IN, but may be ANY or NONE for certain updates
|
||
//
|
||
|
||
if ( fUpdatePacket )
|
||
{
|
||
switch( pRecord->Flags.S.Section )
|
||
{
|
||
case DNSREC_PREREQ:
|
||
|
||
class = PrereqClassArray
|
||
[ pRecord->wDataLength == 0 ][ pRecord->Flags.S.Delete ];
|
||
ttl = 0;
|
||
break;
|
||
|
||
case DNSREC_UPDATE:
|
||
case DNSREC_ADDITIONAL:
|
||
|
||
class = UpdateClassArray
|
||
[ pRecord->wDataLength == 0 ][ pRecord->Flags.S.Delete ];
|
||
|
||
if ( class != DNS_RCLASS_INTERNET )
|
||
{
|
||
ttl = 0;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
DNS_PRINT(( "ERROR: invalid RR section.\n" ));
|
||
return( ERROR_INVALID_DATA );
|
||
}
|
||
if ( class == 0 )
|
||
{
|
||
DNS_PRINT(( "ERROR: no update class corresponding to RR flags.\n" ));
|
||
return( ERROR_INVALID_DATA );
|
||
}
|
||
}
|
||
else
|
||
{
|
||
class = DNS_RCLASS_INTERNET;
|
||
}
|
||
|
||
//
|
||
// write RR wire structure
|
||
// - zero datalength to handle no data case
|
||
//
|
||
|
||
pwireRecord = (PDNS_WIRE_RECORD) pchBuf;
|
||
|
||
*(UNALIGNED WORD *) &pwireRecord->RecordType = htons( pRecord->wType );
|
||
*(UNALIGNED WORD *) &pwireRecord->RecordClass = class;
|
||
*(UNALIGNED DWORD *) &pwireRecord->TimeToLive = htonl( ttl );
|
||
*(UNALIGNED WORD *) &pwireRecord->DataLength = 0;
|
||
|
||
return( ERROR_SUCCESS );
|
||
}
|
||
|
||
|
||
|
||
PCHAR
|
||
Dns_WriteRecordStructureToPacketEx(
|
||
IN OUT PCHAR pchBuf,
|
||
IN WORD wType,
|
||
IN WORD wClass,
|
||
IN DWORD dwTtl,
|
||
IN WORD wDataLength
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Write wire record structure for given record.
|
||
|
||
Arguments:
|
||
|
||
pchBuf - ptr to next byte in packet buffer
|
||
|
||
Return Value:
|
||
|
||
Ptr to data section of record.
|
||
|
||
--*/
|
||
{
|
||
PDNS_WIRE_RECORD pwireRecord;
|
||
|
||
// DCR_PERF: optimize RR write to packet?
|
||
|
||
pwireRecord = (PDNS_WIRE_RECORD) pchBuf;
|
||
|
||
*(UNALIGNED WORD *) &pwireRecord->RecordType = htons( wType );
|
||
*(UNALIGNED WORD *) &pwireRecord->RecordClass = htons( wClass );
|
||
*(UNALIGNED DWORD *) &pwireRecord->TimeToLive = htonl( dwTtl );
|
||
*(UNALIGNED WORD *) &pwireRecord->DataLength = htons( wDataLength );
|
||
|
||
return( pchBuf + sizeof(DNS_WIRE_RECORD) );
|
||
}
|
||
|
||
|
||
|
||
VOID
|
||
Dns_SetRecordDatalength(
|
||
IN OUT PDNS_WIRE_RECORD pRecord,
|
||
IN WORD wDataLength
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Reset record datalength.
|
||
|
||
Arguments:
|
||
|
||
pRecord - wire record to reset
|
||
|
||
wDataLength - data length
|
||
|
||
Return Value:
|
||
|
||
Ptr to data section of record.
|
||
|
||
--*/
|
||
{
|
||
WORD flippedWord;
|
||
|
||
INLINE_WORD_FLIP( flippedWord, wDataLength );
|
||
|
||
*(UNALIGNED WORD *) &pRecord->DataLength = flippedWord;
|
||
}
|
||
|
||
|
||
|
||
|
||
DNS_STATUS
|
||
Dns_AddRecordsToMessage(
|
||
IN OUT PDNS_MSG_BUF pMsg,
|
||
IN PDNS_RECORD pRecord,
|
||
IN BOOL fUpdateMessage
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Add record or list of records to message.No data RR cases:
|
||
|
||
This includes prereqs and deletes except for specific record cases.
|
||
|
||
Arguments:
|
||
|
||
pMsg - message buffer to write to
|
||
|
||
pRecord - ptr to record (or first of list of records) to write to packet
|
||
|
||
fUpdateMessage -- If TRUE, the message is going to contain an update.
|
||
Therefore the section flags in the pRecord
|
||
should be interpreted for update. Otherwise this is
|
||
for a query message and section flags should be
|
||
interpreted for query.
|
||
|
||
Return Value:
|
||
|
||
ERROR_SUCCESS if successful.
|
||
Error code on failure.
|
||
|
||
--*/
|
||
{
|
||
PCHAR pch = pMsg->pCurrent;
|
||
PCHAR pendBuffer = pMsg->pBufferEnd;
|
||
WORD currentSection = 0;
|
||
WORD section;
|
||
PDNS_NAME pnamePrevious = NULL;
|
||
WORD compressedPreviousName;
|
||
WORD offsetPreviousName;
|
||
PDNS_WIRE_RECORD pwireRecord;
|
||
PCHAR pchnext;
|
||
WORD index;
|
||
DNS_STATUS status = ERROR_SUCCESS;
|
||
|
||
//
|
||
// write each record in list
|
||
//
|
||
|
||
while ( pRecord )
|
||
{
|
||
//
|
||
// determine section for record
|
||
// - may not write to previous section
|
||
|
||
section = (WORD) pRecord->Flags.S.Section;
|
||
if ( section < currentSection )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: Attempt to write record at %p, with section %d\n"
|
||
"\tless than previous section written %d.\n",
|
||
pRecord,
|
||
pRecord->Flags.S.Section,
|
||
currentSection ));
|
||
return( ERROR_INVALID_DATA );
|
||
}
|
||
else if ( section > currentSection )
|
||
{
|
||
currentSection = section;
|
||
SET_CURRENT_RR_COUNT_SECTION( pMsg, section );
|
||
}
|
||
|
||
//
|
||
// write record name
|
||
// - if same as previous, write compressed name
|
||
// - if first write from pRecord
|
||
// - write full name
|
||
// - clear reserved field for offsetting
|
||
//
|
||
|
||
if ( pnamePrevious && !strcmp( pnamePrevious, pRecord->pName ) )
|
||
{
|
||
// compression should always be BACK ptr
|
||
|
||
DNS_ASSERT( offsetPreviousName < pch - (PCHAR)&pMsg->MessageHead );
|
||
|
||
if ( pendBuffer <= pch + sizeof(WORD) )
|
||
{
|
||
return( ERROR_MORE_DATA );
|
||
}
|
||
if ( ! compressedPreviousName )
|
||
{
|
||
compressedPreviousName =
|
||
htons( (WORD)(0xC000 | offsetPreviousName) );
|
||
}
|
||
*(UNALIGNED WORD *)pch = compressedPreviousName;
|
||
pch += sizeof( WORD );
|
||
}
|
||
else
|
||
{
|
||
offsetPreviousName = (WORD)(pch - (PCHAR)&pMsg->MessageHead);
|
||
compressedPreviousName = 0;
|
||
pnamePrevious = pRecord->pName;
|
||
|
||
pch = Dns_WriteDottedNameToPacket(
|
||
pch,
|
||
pendBuffer,
|
||
pnamePrevious,
|
||
NULL,
|
||
0,
|
||
( RECORD_CHARSET(pRecord) == DnsCharSetUnicode ) );
|
||
|
||
if ( !pch )
|
||
{
|
||
// DCR: distinguish out of space errors from name errors during write
|
||
return( DNS_ERROR_INVALID_NAME );
|
||
}
|
||
}
|
||
|
||
//
|
||
// write record structure
|
||
//
|
||
|
||
if ( pch + sizeof(DNS_WIRE_RECORD) >= pendBuffer )
|
||
{
|
||
return( ERROR_MORE_DATA );
|
||
}
|
||
|
||
status = Dns_WriteRecordStructureToPacket(
|
||
pch,
|
||
pRecord,
|
||
fUpdateMessage );
|
||
if ( status != ERROR_SUCCESS )
|
||
{
|
||
return( status );
|
||
}
|
||
|
||
pwireRecord = (PDNS_WIRE_RECORD) pch;
|
||
pch += sizeof( DNS_WIRE_RECORD );
|
||
|
||
//
|
||
// record data
|
||
//
|
||
|
||
if ( pRecord->wDataLength )
|
||
{
|
||
index = INDEX_FOR_TYPE( pRecord->wType );
|
||
DNS_ASSERT( index <= MAX_RECORD_TYPE_INDEX );
|
||
|
||
if ( index && RRWriteTable[ index ] )
|
||
{
|
||
pchnext = RRWriteTable[ index ](
|
||
pRecord,
|
||
pch,
|
||
pendBuffer
|
||
);
|
||
if ( ! pchnext )
|
||
{
|
||
status = GetLastError();
|
||
DNS_PRINT((
|
||
"ERROR: Record write routine failure for record type %d.\n\n"
|
||
"\tstatus = %p\n",
|
||
pRecord->wType,
|
||
status ));
|
||
return( status );
|
||
}
|
||
}
|
||
else
|
||
{
|
||
// write unknown types -- as RAW data only
|
||
|
||
DNS_PRINT((
|
||
"WARNING: Writing unknown type %d to message\n",
|
||
pRecord->wType ));
|
||
|
||
if ( pendBuffer - pch <= pRecord->wDataLength )
|
||
{
|
||
return( ERROR_MORE_DATA );
|
||
}
|
||
memcpy(
|
||
pch,
|
||
(PCHAR) &pRecord->Data,
|
||
pRecord->wDataLength );
|
||
pchnext = pch + pRecord->wDataLength;
|
||
}
|
||
|
||
//
|
||
// set packet record data length
|
||
//
|
||
|
||
DNS_ASSERT( (pchnext - pch) < MAXWORD );
|
||
*(UNALIGNED WORD *) &pwireRecord->DataLength =
|
||
htons( (WORD)(pchnext - pch) );
|
||
pch = pchnext;
|
||
}
|
||
|
||
// increment message record count
|
||
|
||
CURRENT_RR_COUNT_FIELD(pMsg)++;
|
||
|
||
pRecord = pRecord->pNext;
|
||
}
|
||
|
||
//
|
||
// resest message current ptr
|
||
//
|
||
|
||
pMsg->pCurrent = pch;
|
||
|
||
IF_DNSDBG( INIT )
|
||
{
|
||
DnsDbg_Message(
|
||
"Packet after adding records:",
|
||
pMsg );
|
||
}
|
||
|
||
return( status );
|
||
}
|
||
|
||
|
||
|
||
//
|
||
// Reading from packet
|
||
//
|
||
|
||
PCHAR
|
||
_fastcall
|
||
Dns_SkipPacketName(
|
||
IN PCHAR pch,
|
||
IN PCHAR pchEnd
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Skips over name in packet
|
||
|
||
Arguments:
|
||
|
||
pch - ptr to start of name to skip
|
||
|
||
pchEnd - ptr to byte after end of packet
|
||
|
||
Return Value:
|
||
|
||
Ptr to next byte in buffer
|
||
NULL if bad name
|
||
|
||
--*/
|
||
{
|
||
register UCHAR cch;
|
||
register UCHAR cflag;
|
||
|
||
//
|
||
// Loop until end of name
|
||
//
|
||
|
||
while ( pch < pchEnd )
|
||
{
|
||
cch = *pch++;
|
||
cflag = cch & 0xC0;
|
||
|
||
//
|
||
// normal label
|
||
// - skip to next label and continue
|
||
// - stop only if at 0 (root) label
|
||
//
|
||
|
||
if ( cflag == 0 )
|
||
{
|
||
if ( cch )
|
||
{
|
||
pch += cch;
|
||
continue;
|
||
}
|
||
return( pch );
|
||
}
|
||
|
||
//
|
||
// compression
|
||
// - skip second byte in compression and return
|
||
//
|
||
|
||
else if ( cflag == 0xC0 )
|
||
{
|
||
pch++;
|
||
return( pch );
|
||
}
|
||
else
|
||
{
|
||
DNSDBG( READ, (
|
||
"ERROR: bad packet name label byte %02 at 0x%p\n",
|
||
cch,
|
||
pch - 1
|
||
));
|
||
return( NULL );
|
||
}
|
||
}
|
||
|
||
DNSDBG( READ, (
|
||
"ERROR: packet name at %p reads past end of packet at %p\n",
|
||
pch,
|
||
pchEnd
|
||
));
|
||
|
||
return( NULL );
|
||
}
|
||
|
||
|
||
PCHAR
|
||
_fastcall
|
||
Dns_SkipPacketRecord(
|
||
IN PCHAR pchRecord,
|
||
IN PCHAR pchMsgEnd
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Skips over packet RR.
|
||
This is RR structure and data, not the owner name.
|
||
|
||
Arguments:
|
||
|
||
pchRecord - ptr to start of RR structure.
|
||
|
||
pchMsgEnd - end of message
|
||
|
||
Return Value:
|
||
|
||
Ptr to next record in packet.
|
||
NULL if RR outside packet or invalid.
|
||
|
||
--*/
|
||
{
|
||
//
|
||
// skip RR struct
|
||
//
|
||
|
||
pchRecord += sizeof(DNS_WIRE_RECORD);
|
||
if ( pchRecord > pchMsgEnd )
|
||
{
|
||
return( NULL );
|
||
}
|
||
|
||
// read datalength and skip data
|
||
// datalength field is a WORD, at end of record header
|
||
|
||
pchRecord += InlineFlipUnalignedWord( pchRecord - sizeof(WORD) );
|
||
|
||
if ( pchRecord > pchMsgEnd )
|
||
{
|
||
return( NULL );
|
||
}
|
||
|
||
return( pchRecord );
|
||
}
|
||
|
||
|
||
|
||
PCHAR
|
||
Dns_SkipToRecord(
|
||
IN PDNS_HEADER pMsgHead,
|
||
IN PCHAR pMsgEnd,
|
||
IN INT iCount
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Skips over some number of DNS records.
|
||
|
||
Arguments:
|
||
|
||
pMsgHead -- ptr to begining of DNS message.
|
||
|
||
pMsgEnd -- ptr to end of DNS message
|
||
|
||
iCount -- if > 0, number of records to skip
|
||
if <= 0, number of records from end of packet
|
||
|
||
Return Value:
|
||
|
||
Ptr to next
|
||
NULL if bad packet.
|
||
|
||
--*/
|
||
{
|
||
PCHAR pch;
|
||
INT i;
|
||
WORD recordCount;
|
||
|
||
//
|
||
// determine how many records to skip
|
||
//
|
||
|
||
recordCount = pMsgHead->QuestionCount
|
||
+ pMsgHead->AnswerCount
|
||
+ pMsgHead->NameServerCount
|
||
+ pMsgHead->AdditionalCount;
|
||
|
||
// iCount > 0 is skip count, MUST not be larger than
|
||
// actual count
|
||
|
||
if ( iCount > 0 )
|
||
{
|
||
if ( iCount > recordCount )
|
||
{
|
||
return( NULL );
|
||
}
|
||
}
|
||
|
||
// iCount <= 0 then (-iCount) is number of records
|
||
// from the last record
|
||
|
||
else
|
||
{
|
||
iCount += recordCount;
|
||
if ( iCount < 0 )
|
||
{
|
||
return( NULL );
|
||
}
|
||
}
|
||
|
||
// skip message header
|
||
|
||
pch = (PCHAR) (pMsgHead + 1);
|
||
if ( iCount == 0 )
|
||
{
|
||
return( pch );
|
||
}
|
||
|
||
// skip the question/zone section
|
||
|
||
pch = Dns_SkipPacketName( pch, pMsgEnd );
|
||
if ( !pch )
|
||
{
|
||
return pch;
|
||
}
|
||
pch += sizeof(DNS_WIRE_QUESTION);
|
||
|
||
//
|
||
// skip regular records
|
||
//
|
||
|
||
iCount--;
|
||
for ( i=0; i<iCount; i++ )
|
||
{
|
||
pch = Dns_SkipPacketName( pch, pMsgEnd );
|
||
if ( !pch )
|
||
{
|
||
return pch;
|
||
}
|
||
pch = Dns_SkipPacketRecord( pch, pMsgEnd );
|
||
if ( !pch )
|
||
{
|
||
return pch;
|
||
}
|
||
}
|
||
|
||
DNSDBG( READ, (
|
||
"Leaving SkipToRecord, current ptr = %p, offset = %04x\n"
|
||
"\tskipped %d records\n",
|
||
pch,
|
||
(WORD) (pch - (PCHAR)pMsgHead),
|
||
iCount+1 ));
|
||
|
||
return( pch );
|
||
}
|
||
|
||
|
||
|
||
PCHAR
|
||
_fastcall
|
||
Dns_ReadPacketName(
|
||
IN OUT PCHAR pchNameBuffer,
|
||
OUT PWORD pwNameLength,
|
||
IN OUT PWORD pwNameOffset, OPTIONAL
|
||
OUT PBOOL pfNameSameAsPrevious, OPTIONAL
|
||
IN PCHAR pchName,
|
||
IN PCHAR pchStart,
|
||
IN PCHAR pchEnd
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Reads packet name and converts it to DNS-dotted format.
|
||
|
||
Arguments:
|
||
|
||
pchNameBuffer - buffer to write name into; contains previous name, if any
|
||
|
||
pwNameLength - length of name written to buffer; does not include
|
||
terminating NULL
|
||
|
||
pwNameOffset - addr with previous names offset (zero if no previous name);
|
||
on return, contains this name's offset
|
||
OPTIONAL but must exist if fNameSameAsPrevious exists
|
||
|
||
pfNameSameAsPrevious - addr of flag set if this name is same as previous;
|
||
OPTIONAL but must exist if pwNameOffset exists
|
||
|
||
pchName - ptr to name in packet
|
||
|
||
pchStart - start of DNS message
|
||
|
||
pchEnd - ptr to byte after end of DNS message
|
||
|
||
Return Value:
|
||
|
||
Ptr to next byte in packet.
|
||
NULL on error.
|
||
|
||
--*/
|
||
{
|
||
register PUCHAR pch = pchName;
|
||
register UCHAR cch;
|
||
register UCHAR cflag;
|
||
PCHAR pchdotted;
|
||
PCHAR pbufferEnd;
|
||
PCHAR pchreturn = NULL;
|
||
|
||
DNS_ASSERT( pch > pchStart && pchEnd > pchStart );
|
||
DNS_ASSERT( (pwNameOffset && pfNameSameAsPrevious) ||
|
||
(!pwNameOffset && !pfNameSameAsPrevious) );
|
||
|
||
|
||
//
|
||
// read through labels and/or compression until reach end of name
|
||
//
|
||
|
||
pbufferEnd = pchNameBuffer + DNS_MAX_NAME_LENGTH;
|
||
pchdotted = pchNameBuffer;
|
||
|
||
while ( pch < pchEnd )
|
||
{
|
||
cch = *pch++;
|
||
|
||
//
|
||
// at root label
|
||
// - if root name, write single '.'
|
||
// - otherwise strip trailing dot from last label
|
||
// - save length written
|
||
// - NULL teminate name
|
||
// - set same as previous FALSE
|
||
// - save packet offset to this name
|
||
// - return next byte in buffer
|
||
//
|
||
|
||
if ( cch == 0 )
|
||
{
|
||
if ( pchdotted == pchNameBuffer )
|
||
{
|
||
*pchdotted++ = '.';
|
||
}
|
||
else
|
||
{
|
||
pchdotted--;
|
||
}
|
||
*pwNameLength = (WORD)(pchdotted - pchNameBuffer);
|
||
*pchdotted = 0;
|
||
if ( pwNameOffset )
|
||
{
|
||
*pfNameSameAsPrevious = FALSE;
|
||
*pwNameOffset = (WORD)(pchName - pchStart);
|
||
}
|
||
return( pchreturn ? pchreturn : pch );
|
||
}
|
||
|
||
cflag = cch & 0xC0;
|
||
|
||
//
|
||
// regular label
|
||
// - copy label to buffer
|
||
// - jump to next label
|
||
|
||
if ( cflag == 0 )
|
||
{
|
||
PCHAR pchnext = pch + cch;
|
||
|
||
if ( pchnext >= pchEnd )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: Packet name at %p extends past end of buffer\n",
|
||
pchName ));
|
||
goto Failed;
|
||
}
|
||
if ( pchdotted + cch + 1 >= pbufferEnd )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: Packet name at %p exceeds max length\n",
|
||
pchName ));
|
||
goto Failed;
|
||
}
|
||
memcpy(
|
||
pchdotted,
|
||
pch,
|
||
cch );
|
||
|
||
pchdotted += cch;
|
||
*pchdotted++ = '.';
|
||
pch = pchnext;
|
||
continue;
|
||
}
|
||
|
||
//
|
||
// offset
|
||
// - get offset
|
||
// - if offset at start of name compare to previous name offset
|
||
// - otherwise follow offset to build new name
|
||
//
|
||
|
||
if ( cflag == 0xC0 )
|
||
{
|
||
WORD offset;
|
||
PCHAR pchoffset;
|
||
|
||
offset = (cch ^ 0xC0);
|
||
offset <<= 8;
|
||
offset |= *pch;
|
||
pchoffset = --pch;
|
||
|
||
//
|
||
// first offset
|
||
// - save return pointer
|
||
//
|
||
// if name is entirely offset
|
||
// - same as previous offset -- done
|
||
// - if not still save this offset rather than offset
|
||
// to name itself (first answer is usually just offset
|
||
// to question, subsequent answer RRs continue to reference
|
||
// question offset, not first answer)
|
||
//
|
||
|
||
if ( !pchreturn )
|
||
{
|
||
DNS_ASSERT( pch >= pchName );
|
||
pchreturn = pch+2;
|
||
|
||
if ( pchoffset == pchName && pwNameOffset )
|
||
{
|
||
if ( *pwNameOffset == offset )
|
||
{
|
||
*pfNameSameAsPrevious = TRUE;
|
||
return( pchreturn );
|
||
}
|
||
else
|
||
{
|
||
// save offset that comprises name
|
||
// then kill out copy of return ptr so don't
|
||
// return offset to pchName when finish copy
|
||
|
||
*pwNameOffset = offset;
|
||
*pfNameSameAsPrevious = FALSE;
|
||
pwNameOffset = NULL;
|
||
}
|
||
}
|
||
}
|
||
|
||
//
|
||
// make jump to new bytes and continue
|
||
// - verify offset is BEFORE current name
|
||
// and BEFORE current ptr
|
||
|
||
pch = pchStart + offset;
|
||
|
||
if ( pch >= pchName || pch >= pchoffset )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: Bogus name offset %d, encountered at %p\n"
|
||
"\tto location %p past current position or original name.\n",
|
||
offset,
|
||
pchoffset,
|
||
pch ));
|
||
goto Failed;
|
||
}
|
||
continue;
|
||
}
|
||
|
||
// any other label byte is bogus
|
||
|
||
else
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: bogus name label byte %02x at %p\n",
|
||
cch,
|
||
pch - 1 ));
|
||
goto Failed;
|
||
}
|
||
}
|
||
|
||
DNS_PRINT((
|
||
"ERROR: packet name at %p reads to ptr %p past end of packet at %p\n",
|
||
pchName,
|
||
pch,
|
||
pchEnd ));
|
||
|
||
//
|
||
// failed
|
||
// - return NULL
|
||
// - set OUT params, keeps prefix happy on higher level calls
|
||
//
|
||
|
||
Failed:
|
||
|
||
*pwNameLength = 0;
|
||
if ( pwNameOffset )
|
||
{
|
||
*pwNameOffset = 0;
|
||
}
|
||
if ( pfNameSameAsPrevious )
|
||
{
|
||
*pfNameSameAsPrevious = FALSE;
|
||
}
|
||
return ( NULL );
|
||
}
|
||
|
||
|
||
|
||
PCHAR
|
||
_fastcall
|
||
Dns_ReadPacketNameAllocate(
|
||
IN OUT PCHAR * ppchName,
|
||
OUT PWORD pwNameLength,
|
||
IN OUT PWORD pwPrevNameOffset, OPTIONAL
|
||
OUT PBOOL pfNameSameAsPrevious, OPTIONAL
|
||
IN PCHAR pchPacketName,
|
||
IN PCHAR pchStart,
|
||
IN PCHAR pchEnd
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Reads packet name and creates (allocates) a copy in DNS-dotted format.
|
||
|
||
Arguments:
|
||
|
||
ppchName - addr to recv resulting name ptr
|
||
|
||
pwNameLength - length of name written to buffer
|
||
|
||
pwNameOffset - addr with previous names offset (zero if no previous name);
|
||
on return, contains this name's offset
|
||
OPTIONAL but must exist if fNameSameAsPrevious exists
|
||
|
||
fNameSameAsPrevious - addr of flag set if this name is same as previous;
|
||
OPTIONAL but must exist if pwNameOffset exists
|
||
|
||
pchPacketName - pch to name in packet
|
||
|
||
pchStart - start of DNS message
|
||
|
||
pchEnd - ptr to byte after end of DNS message
|
||
|
||
Return Value:
|
||
|
||
Ptr to next byte in packet.
|
||
NULL on error.
|
||
|
||
--*/
|
||
{
|
||
PCHAR pch;
|
||
PCHAR pallocName;
|
||
CHAR nameBuffer[ DNS_MAX_NAME_BUFFER_LENGTH ];
|
||
WORD nameLength = DNS_MAX_NAME_BUFFER_LENGTH;
|
||
|
||
//
|
||
// read packet name into buffer
|
||
//
|
||
|
||
pch = Dns_ReadPacketName(
|
||
nameBuffer,
|
||
& nameLength,
|
||
pwPrevNameOffset,
|
||
pfNameSameAsPrevious,
|
||
pchPacketName,
|
||
pchStart,
|
||
pchEnd );
|
||
if ( !pch )
|
||
{
|
||
return( pch );
|
||
}
|
||
|
||
//
|
||
// allocate buffer for packet name
|
||
// - nameLength does not include terminating NULL
|
||
//
|
||
|
||
nameLength++;
|
||
pallocName = (PCHAR) ALLOCATE_HEAP( nameLength );
|
||
if ( !pallocName )
|
||
{
|
||
return( NULL );
|
||
}
|
||
|
||
RtlCopyMemory(
|
||
pallocName,
|
||
nameBuffer,
|
||
nameLength );
|
||
|
||
*ppchName = pallocName;
|
||
*pwNameLength = --nameLength;
|
||
|
||
DNSDBG( READ, (
|
||
"Allocated copy of packet name %s length %d\n",
|
||
pallocName,
|
||
nameLength ));
|
||
|
||
return( pch );
|
||
}
|
||
|
||
|
||
|
||
DNS_STATUS
|
||
Dns_ExtractRecordsFromMessage(
|
||
IN PDNS_MSG_BUF pMsg,
|
||
IN BOOL fUnicode,
|
||
OUT PDNS_RECORD * ppRecord
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Extract records from packet.
|
||
|
||
Arguments:
|
||
|
||
pMsg - message buffer to write to
|
||
|
||
fUnicode - flag indicating strings in record should be unicode
|
||
|
||
Return Value:
|
||
|
||
Ptr to parsed record list if any.
|
||
NULL if no record list or error.
|
||
|
||
--*/
|
||
{
|
||
PDNS_MESSAGE_BUFFER pDnsBuffer = (PDNS_MESSAGE_BUFFER) &pMsg->MessageHead;
|
||
|
||
return Dns_ExtractRecordsFromBuffer(
|
||
pDnsBuffer,
|
||
pMsg->MessageLength,
|
||
fUnicode,
|
||
ppRecord );
|
||
}
|
||
|
||
|
||
|
||
DNS_STATUS
|
||
Dns_ExtractRecordsFromBuffer(
|
||
IN PDNS_MESSAGE_BUFFER pDnsBuffer,
|
||
IN WORD wMessageLength,
|
||
IN BOOL fUnicode,
|
||
OUT PDNS_RECORD * ppRecord
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Extract records from packet buffer.
|
||
|
||
Arguments:
|
||
|
||
pDnsBuffer - message buffer to read from
|
||
|
||
fUnicode - flag indicating strings in record should be unicode
|
||
|
||
Return Value:
|
||
|
||
Ptr to parsed record list if any.
|
||
NULL if no record list or error.
|
||
|
||
--*/
|
||
{
|
||
register PCHAR pch;
|
||
PDNS_HEADER pwireMsg = (PDNS_HEADER) pDnsBuffer;
|
||
PCHAR pchpacketEnd;
|
||
DNS_PARSED_RR parsedRR;
|
||
LPSTR pnameOwner;
|
||
LPSTR pnameNew = NULL;
|
||
DNS_CHARSET outCharSet;
|
||
WORD countRR;
|
||
WORD countSection;
|
||
WORD typePrevious = 0;
|
||
WORD nameOffset = 0;
|
||
WORD nameLength;
|
||
WORD index;
|
||
BYTE section;
|
||
BOOL fnameSameAsPrevious;
|
||
PDNS_RECORD pnewRR;
|
||
DNS_RRSET rrset;
|
||
DNS_STATUS status;
|
||
DNS_STATUS rcodeStatus;
|
||
CHAR nameBuffer[ DNS_MAX_NAME_BUFFER_LENGTH ];
|
||
DNS_RECORD recordTemp;
|
||
PWORD pCurrentCountField = NULL;
|
||
|
||
DNSDBG( READ, (
|
||
"Dns_ExtractRecordsFromBuffer( %p, len=%d )\n",
|
||
pDnsBuffer,
|
||
wMessageLength
|
||
));
|
||
|
||
//
|
||
// error code
|
||
// - map RCODE to DNS error
|
||
// - if other than NAME_ERROR, don't bother parsing
|
||
//
|
||
|
||
rcodeStatus = pwireMsg->ResponseCode;
|
||
if ( rcodeStatus != 0 )
|
||
{
|
||
rcodeStatus = Dns_MapRcodeToStatus( pwireMsg->ResponseCode );
|
||
if ( rcodeStatus != DNS_ERROR_RCODE_NAME_ERROR )
|
||
{
|
||
DNSDBG( READ, (
|
||
"No records extracted from response\n"
|
||
"\tresponse code = %d\n",
|
||
pwireMsg->ResponseCode ));
|
||
return( rcodeStatus );
|
||
}
|
||
}
|
||
|
||
DNS_RRSET_INIT( rrset );
|
||
|
||
//
|
||
// detemine char set
|
||
//
|
||
|
||
if ( fUnicode )
|
||
{
|
||
outCharSet = DnsCharSetUnicode;
|
||
}
|
||
else
|
||
{
|
||
outCharSet = DnsCharSetUtf8;
|
||
}
|
||
|
||
//
|
||
// read RRs in list of records
|
||
//
|
||
// loop through all resource records
|
||
// - skip question
|
||
// - build DNS_RECORD structure for other records
|
||
//
|
||
|
||
pchpacketEnd = (PCHAR)pwireMsg + wMessageLength;
|
||
pch = pDnsBuffer->MessageBody;
|
||
|
||
section = DNSREC_QUESTION;
|
||
pCurrentCountField = &pwireMsg->QuestionCount;
|
||
countSection = pwireMsg->QuestionCount;
|
||
countRR = 0;
|
||
|
||
while( 1 )
|
||
{
|
||
//
|
||
// changing sections
|
||
// save section number and RR count for current section
|
||
// note need immediate loop back to handle empty section
|
||
//
|
||
|
||
countRR++;
|
||
if ( countRR > countSection )
|
||
{
|
||
if ( section == DNSREC_ADDITIONAL )
|
||
{
|
||
break;
|
||
}
|
||
section++;
|
||
pCurrentCountField++;
|
||
countSection = *(pCurrentCountField);
|
||
countRR = 0;
|
||
continue;
|
||
}
|
||
|
||
// validity check next RR
|
||
|
||
if ( pch >= pchpacketEnd )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: reading bad packet %p.\n"
|
||
"\tat end of packet length with more records to process\n"
|
||
"\tpacket length = %ld\n"
|
||
"\tcurrent offset = %ld\n",
|
||
wMessageLength,
|
||
pch - (PCHAR)pwireMsg
|
||
));
|
||
goto PacketError;
|
||
}
|
||
|
||
//
|
||
// skip question
|
||
//
|
||
|
||
if ( section == DNSREC_QUESTION )
|
||
{
|
||
pch = Dns_SkipPacketName(
|
||
pch,
|
||
pchpacketEnd );
|
||
if ( !pch )
|
||
{
|
||
DNS_PRINT(( "ERROR: bad question name.\n" ));
|
||
goto PacketError;
|
||
}
|
||
pch += sizeof(DNS_WIRE_QUESTION);
|
||
if ( pch > pchpacketEnd )
|
||
{
|
||
DNS_PRINT(( "ERROR: question exceeds packet length.\n" ));
|
||
goto PacketError;
|
||
}
|
||
continue;
|
||
}
|
||
|
||
//
|
||
// read name, determining if same as previous name
|
||
//
|
||
|
||
IF_DNSDBG( READ2 )
|
||
{
|
||
DnsDbg_Lock();
|
||
DNS_PRINT((
|
||
"Reading record at offset %x\n",
|
||
(WORD)(pch - (PCHAR)pwireMsg) ));
|
||
|
||
DnsDbg_PacketName(
|
||
"Record name ",
|
||
pch,
|
||
pwireMsg,
|
||
pchpacketEnd,
|
||
"\n" );
|
||
DnsDbg_Unlock();
|
||
}
|
||
pch = Dns_ReadPacketName(
|
||
nameBuffer,
|
||
& nameLength,
|
||
& nameOffset,
|
||
& fnameSameAsPrevious,
|
||
pch,
|
||
(PCHAR) pwireMsg,
|
||
pchpacketEnd );
|
||
if ( ! pch )
|
||
{
|
||
DNS_PRINT(( "ERROR: bad packet name.\n" ));
|
||
goto PacketError;
|
||
}
|
||
IF_DNSDBG( READ2 )
|
||
{
|
||
DNS_PRINT((
|
||
"Owner name of record %s\n"
|
||
"\tlength = %d\n"
|
||
"\toffset = %d\n"
|
||
"\tfSameAsPrevious = %d\n",
|
||
nameBuffer,
|
||
nameLength,
|
||
nameOffset,
|
||
fnameSameAsPrevious ));
|
||
}
|
||
|
||
//
|
||
// extract RR info, type, datalength
|
||
// - verify RR within message
|
||
//
|
||
|
||
pch = Dns_ReadRecordStructureFromPacket(
|
||
pch,
|
||
pchpacketEnd,
|
||
& parsedRR );
|
||
if ( !pch )
|
||
{
|
||
DNS_PRINT(( "ERROR: bad RR struct out of packet.\n" ));
|
||
goto PacketError;
|
||
}
|
||
|
||
//
|
||
// on type change, always have new RR set
|
||
// - setup for new name
|
||
//
|
||
|
||
if ( parsedRR.Type != typePrevious )
|
||
{
|
||
fnameSameAsPrevious = FALSE;
|
||
typePrevious = parsedRR.Type;
|
||
}
|
||
|
||
//
|
||
// make copy of new name
|
||
//
|
||
// DCR_FIX0: name same as previous
|
||
// flag indicates only that name not compressed to previous
|
||
// name (or previous compression)
|
||
// actually need abolute ingnore case compare
|
||
// with last records name to be sure that name not previous
|
||
//
|
||
|
||
if ( !fnameSameAsPrevious )
|
||
{
|
||
pnameNew = Dns_NameCopyAllocate(
|
||
nameBuffer,
|
||
(UCHAR) nameLength,
|
||
DnsCharSetUtf8, // UTF8 string in
|
||
outCharSet
|
||
);
|
||
pnameOwner = pnameNew;
|
||
DNSDBG( READ2, (
|
||
"Copy of owner name of record being read from packet %s\n",
|
||
pnameOwner ));
|
||
}
|
||
DNS_ASSERT( pnameOwner );
|
||
DNS_ASSERT( pnameNew || fnameSameAsPrevious );
|
||
|
||
//
|
||
// TSIG record requires owner name for versioning
|
||
//
|
||
|
||
recordTemp.pName = pnameOwner;
|
||
|
||
//
|
||
// read RR data for type
|
||
//
|
||
|
||
index = INDEX_FOR_TYPE( parsedRR.Type );
|
||
DNS_ASSERT( index <= MAX_RECORD_TYPE_INDEX );
|
||
|
||
if ( !index || !RRReadTable[ index ] )
|
||
{
|
||
// unknown types -- index to NULL type to use
|
||
// FlatRecordRead()
|
||
|
||
DNS_PRINT((
|
||
"WARNING: Reading unknown record type %d from message\n",
|
||
parsedRR.Type ));
|
||
|
||
index = DNS_TYPE_NULL;
|
||
}
|
||
|
||
pnewRR = RRReadTable[ index ](
|
||
&recordTemp,
|
||
outCharSet,
|
||
(PCHAR) pDnsBuffer,
|
||
parsedRR.pchData,
|
||
pch // end of record data
|
||
);
|
||
if ( ! pnewRR )
|
||
{
|
||
status = GetLastError();
|
||
ASSERT( status != ERROR_SUCCESS );
|
||
|
||
DNS_PRINT((
|
||
"ERROR: RRReadTable routine failure for type %d.\n"
|
||
"\tstatus = %p\n"
|
||
"\tpchdata = %p\n"
|
||
"\tpchend = %p\n",
|
||
parsedRR.Type,
|
||
status,
|
||
parsedRR.pchData,
|
||
pch ));
|
||
|
||
if ( status == ERROR_SUCCESS )
|
||
{
|
||
status = DNS_ERROR_NO_MEMORY;
|
||
}
|
||
goto Failed;
|
||
}
|
||
|
||
//
|
||
// write record info
|
||
// - first RR in set gets new name allocation
|
||
// and is responsible for cleanup
|
||
// - no data cleanup necessary as all data is
|
||
// contained in the RR allocation
|
||
//
|
||
|
||
pnewRR->pName = pnameOwner;
|
||
pnewRR->wType = parsedRR.Type;
|
||
pnewRR->dwTtl = parsedRR.Ttl;
|
||
pnewRR->Flags.S.Section = section;
|
||
pnewRR->Flags.S.CharSet = outCharSet;
|
||
FLAG_FreeOwner( pnewRR ) = !fnameSameAsPrevious;
|
||
FLAG_FreeData( pnewRR ) = FALSE;
|
||
|
||
// add RR to list
|
||
|
||
DNS_RRSET_ADD( rrset, pnewRR );
|
||
|
||
// clear new ptr, as name now part of record
|
||
// this is strictly used to determine when pnameOwner
|
||
// must be cleaned up on failure
|
||
|
||
pnameNew = NULL;
|
||
|
||
} // end loop through packet's records
|
||
|
||
//
|
||
// return parsed record list
|
||
// - return DNS error for RCODE
|
||
// - set special return code to differentiate empty response
|
||
//
|
||
// DCR: should have special REFERRAL response
|
||
// - could overload NOTAUTH rcode
|
||
// DCR: should have special EMPTY_AUTH response
|
||
// - could have empty-auth overload NXRRSET
|
||
//
|
||
// DCR: best check on distinguishing EMPTY_AUTH from REFERRAL
|
||
//
|
||
|
||
if ( pwireMsg->AnswerCount == 0 && rcodeStatus == 0 )
|
||
{
|
||
if ( !rrset.pFirstRR || rrset.pFirstRR->wType == DNS_TYPE_SOA )
|
||
{
|
||
rcodeStatus = DNS_INFO_NO_RECORDS;
|
||
DNSDBG( READ, ( "Empty-auth response at %p.\n", pwireMsg ));
|
||
}
|
||
#if 0
|
||
else if ( rrset.pFirstRR->wType == DNS_TYPE_NS &&
|
||
!pwireMsg->Authoritative )
|
||
{
|
||
rcodeStatus = DNS_INFO_REFERRAL;
|
||
DNSDBG( READ, ( "Referral response at %p.\n", pwireMsg ));
|
||
}
|
||
else
|
||
{
|
||
rcodeStatus = DNS_ERROR_BAD_PACKET;
|
||
DNSDBG( READ, ( "Bogus NO_ERROR response at %p.\n", pwireMsg ));
|
||
}
|
||
#endif
|
||
}
|
||
|
||
// verify never turn RCODE result into SUCCESS
|
||
|
||
ASSERT( pwireMsg->ResponseCode == 0 || rcodeStatus != ERROR_SUCCESS );
|
||
ASSERT( pnameNew == NULL );
|
||
|
||
*ppRecord = rrset.pFirstRR;
|
||
|
||
IF_DNSDBG( RECV )
|
||
{
|
||
DnsDbg_RecordSet(
|
||
"Extracted records:\n",
|
||
*ppRecord );
|
||
}
|
||
return( rcodeStatus );
|
||
|
||
|
||
PacketError:
|
||
|
||
DNS_PRINT(( "ERROR: bad packet in buffer.\n" ));
|
||
status = DNS_ERROR_BAD_PACKET;
|
||
|
||
Failed:
|
||
|
||
if ( pnameNew )
|
||
{
|
||
FREE_HEAP( pnameNew );
|
||
}
|
||
|
||
Dns_RecordListFree(
|
||
rrset.pFirstRR,
|
||
TRUE // free owner names also
|
||
);
|
||
|
||
return( status );
|
||
}
|
||
|
||
|
||
void
|
||
Dns_NormalizeAllRecordTtls(
|
||
IN PDNS_RECORD pRecord
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Finds the lowest Ttl value in RR set and the sets all
|
||
records to that value.
|
||
|
||
Arguments:
|
||
|
||
pRecord - record set to normalize ttl values of.
|
||
|
||
Return Value:
|
||
|
||
None
|
||
|
||
--*/
|
||
{
|
||
PDNS_RECORD pTemp = pRecord;
|
||
DWORD dwTtl;
|
||
WORD wType;
|
||
|
||
//
|
||
// Get the Ttl of the first record (if there is one)
|
||
//
|
||
if ( pTemp )
|
||
{
|
||
dwTtl = pTemp->dwTtl;
|
||
wType = pTemp->wType;
|
||
pTemp = pTemp->pNext;
|
||
}
|
||
|
||
//
|
||
// Walk any remaining records looking for an even lower ttl value
|
||
//
|
||
while ( pTemp &&
|
||
pTemp->wType == wType &&
|
||
pTemp->Flags.S.Section == DNSREC_ANSWER )
|
||
{
|
||
if ( pTemp->dwTtl < dwTtl )
|
||
{
|
||
dwTtl = pTemp->dwTtl;
|
||
}
|
||
|
||
pTemp = pTemp->pNext;
|
||
}
|
||
|
||
//
|
||
// Set all records to this lowest ttl value
|
||
//
|
||
pTemp = pRecord;
|
||
|
||
while ( pTemp &&
|
||
pTemp->wType == wType &&
|
||
pTemp->Flags.S.Section == DNSREC_ANSWER )
|
||
{
|
||
pTemp->dwTtl = dwTtl;
|
||
pTemp = pTemp->pNext;
|
||
}
|
||
}
|
||
|
||
|
||
|
||
PCHAR
|
||
Dns_ReadRecordStructureFromPacket(
|
||
IN PCHAR pchPacket,
|
||
IN PCHAR pchMsgEnd,
|
||
IN OUT PDNS_PARSED_RR pParsedRR
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Read record structure from packet.
|
||
|
||
Arguments:
|
||
|
||
pchPacket - ptr to record structure in packet
|
||
|
||
pRecord - ptr to record structure to receive record structure
|
||
with fields in host order (and aligned).
|
||
|
||
Return Value:
|
||
|
||
Ptr to next record in packet -- based on datalength.
|
||
Zero on error.
|
||
|
||
--*/
|
||
{
|
||
DNSDBG( READ2, (
|
||
"Dns_ReadRecordStructureFromPacket(%p).\n",
|
||
pchPacket ));
|
||
|
||
//
|
||
// verify record structure within packet
|
||
//
|
||
|
||
if ( pchPacket + sizeof(DNS_WIRE_RECORD) > pchMsgEnd )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: record structure at %p is not within packet!.\n",
|
||
pchPacket ));
|
||
return( 0 );
|
||
}
|
||
|
||
//
|
||
// flip fields and write to aligned struct
|
||
//
|
||
|
||
pParsedRR->pchRR = pchPacket;
|
||
|
||
pParsedRR->Type = InlineFlipUnalignedWord( pchPacket );
|
||
pchPacket += sizeof(WORD);
|
||
pParsedRR->Class = InlineFlipUnalignedWord( pchPacket );
|
||
pchPacket += sizeof(WORD);
|
||
pParsedRR->Ttl = InlineFlipUnalignedDword( pchPacket );
|
||
pchPacket += sizeof(DWORD);
|
||
pParsedRR->DataLength = InlineFlipUnalignedWord( pchPacket );
|
||
pchPacket += sizeof(WORD);
|
||
|
||
pParsedRR->pchData = pchPacket;
|
||
|
||
//
|
||
// verify datalength does not extend beyond packet end
|
||
//
|
||
|
||
pchPacket += pParsedRR->DataLength;
|
||
pParsedRR->pchNextRR = pchPacket;
|
||
|
||
if ( pchPacket > pchMsgEnd )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: record data at %p (length %d) is not within packet!.\n",
|
||
pchPacket - pParsedRR->DataLength,
|
||
pParsedRR->DataLength ));
|
||
return( 0 );
|
||
}
|
||
|
||
//
|
||
// return ptr to next record in packet
|
||
//
|
||
|
||
return( pchPacket );
|
||
}
|
||
|
||
|
||
|
||
PDNS_MSG_BUF
|
||
Dns_BuildPacket(
|
||
IN PDNS_HEADER pHeader,
|
||
IN BOOL fNoHeaderCounts,
|
||
IN LPSTR pszQuestionName,
|
||
IN WORD wQuestionType,
|
||
IN PDNS_RECORD pRecords,
|
||
IN DWORD dwFlags,
|
||
IN BOOL fUpdatePacket
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Build packet.
|
||
|
||
Arguments:
|
||
|
||
pHeader -- DNS header to send
|
||
|
||
fNoHeaderCounts - do NOT include record counts in copying header
|
||
|
||
pszName -- DNS name to query
|
||
|
||
wType -- query type
|
||
|
||
pRecords -- address to receive ptr to record list returned from query
|
||
|
||
dwFlags -- query flags
|
||
|
||
aipDnsServers -- specific DNS servers to query;
|
||
OPTIONAL, if specified overrides normal list associated with machine
|
||
|
||
pDnsNetAdapters -- DNS servers to query; if NULL get current list
|
||
|
||
fUpdatePacket -- If TRUE, the packet is going to contain an update.
|
||
Therefore the section flags in the pRecords
|
||
should be interpreted for update. Otherwise this is
|
||
for a query and section flags will be interpreted for
|
||
query.
|
||
|
||
|
||
Return Value:
|
||
|
||
ERROR_SUCCESS if successful.
|
||
Error code on failure.
|
||
|
||
--*/
|
||
{
|
||
PDNS_MSG_BUF pmsg;
|
||
DWORD length;
|
||
DNS_STATUS status;
|
||
|
||
DNSDBG( WRITE, (
|
||
"Dns_BuildPacket()\n"
|
||
"\tname %s\n"
|
||
"\ttype %d\n"
|
||
"\theader %p\n"
|
||
"\t - counts %d\n"
|
||
"\trecords %p\n"
|
||
"\tflags %p\n"
|
||
"\tfUpdatePacket %p\n",
|
||
pszQuestionName,
|
||
wQuestionType,
|
||
pHeader,
|
||
fNoHeaderCounts,
|
||
pRecords,
|
||
dwFlags,
|
||
fUpdatePacket ));
|
||
|
||
//
|
||
// allocate packet
|
||
// - if just a question, standard UDP will do it
|
||
// - if contains records, then use TCP buffer
|
||
//
|
||
|
||
length = 0;
|
||
if ( pRecords )
|
||
{
|
||
length = DNS_TCP_DEFAULT_PACKET_LENGTH;
|
||
}
|
||
pmsg = Dns_AllocateMsgBuf( (WORD)length );
|
||
if ( !pmsg )
|
||
{
|
||
status = DNS_ERROR_NO_MEMORY;
|
||
goto Failed;
|
||
}
|
||
|
||
//
|
||
// write question?
|
||
//
|
||
|
||
if ( pszQuestionName )
|
||
{
|
||
if ( ! Dns_WriteQuestionToMessage(
|
||
pmsg,
|
||
pszQuestionName,
|
||
wQuestionType,
|
||
(BOOL)!!(dwFlags & DNSQUERY_UNICODE_NAME)
|
||
) )
|
||
{
|
||
status = ERROR_INVALID_NAME;
|
||
goto Failed;
|
||
}
|
||
}
|
||
|
||
//
|
||
// build packet records
|
||
//
|
||
|
||
if ( pRecords )
|
||
{
|
||
status = Dns_AddRecordsToMessage(
|
||
pmsg,
|
||
pRecords,
|
||
fUpdatePacket );
|
||
if ( status != ERROR_SUCCESS )
|
||
{
|
||
DNS_PRINT((
|
||
"ERROR: failure writing records to message.\n" ));
|
||
goto Failed;
|
||
}
|
||
}
|
||
|
||
//
|
||
// overwrite header?
|
||
//
|
||
|
||
if ( pHeader )
|
||
{
|
||
length = sizeof(DNS_HEADER);
|
||
if ( fNoHeaderCounts )
|
||
{
|
||
length = sizeof(DWORD);
|
||
}
|
||
RtlCopyMemory(
|
||
& pmsg->MessageHead,
|
||
pHeader,
|
||
length );
|
||
}
|
||
|
||
// override recursion default, if desired
|
||
|
||
if ( dwFlags & DNS_QUERY_NO_RECURSION )
|
||
{
|
||
pmsg->MessageHead.RecursionDesired = FALSE;
|
||
}
|
||
|
||
// init XID if not set
|
||
|
||
if ( pmsg->MessageHead.Xid == 0 )
|
||
{
|
||
pmsg->MessageHead.Xid = gwTransactionId++;
|
||
}
|
||
|
||
return( pmsg );
|
||
|
||
Failed:
|
||
|
||
SetLastError( status );
|
||
FREE_HEAP( pmsg );
|
||
return( NULL );
|
||
}
|
||
|
||
|
||
|
||
WORD
|
||
Dns_GetRandomXid(
|
||
IN PVOID pSeed
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
Generate "random" XID.
|
||
|
||
Arguments:
|
||
|
||
pSeed -- seed ptr; from stack or heap, provides differentiation beyond time
|
||
|
||
Return Value:
|
||
|
||
XID generated
|
||
|
||
--*/
|
||
{
|
||
SYSTEMTIME systemTime;
|
||
|
||
//
|
||
// may have multiple sessions to different processes\threads
|
||
//
|
||
// use system time hashed in with seed pointer
|
||
// ptr is first pushed down to count 64-bit boundaries, so lack of
|
||
// randomness in last 6bits is not preserved
|
||
//
|
||
|
||
GetSystemTime( &systemTime );
|
||
|
||
// hash millisecs with arbitrary stack location after knocking off any
|
||
// 64-bit boundary constraints
|
||
|
||
return (WORD)( systemTime.wMilliseconds * (PtrToUlong(pSeed) >> 6) );
|
||
}
|
||
|
||
//
|
||
// End packet.c
|
||
//
|