1 // Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 //

    15 

    16 /**

    17  @file DHCPUnicastTranslator.cpp

    18  @internalComponent

    19 */

    20 

    21 #include <in_chk.h>

    22 #include <in_sock.h>

    23 #include <in_bind.h>

    24 #include "in6_opt.h"

    25 #include <udp_hdr.h>

    26 

    27 #include "DHCPUnicastTranslator.h"

    28 #include "HookLog.h"

    29 #include "ipeventlistener.h"

    30 

    31 

    32 

    33 

    34 CDHCPUnicastTranslator::CDHCPUnicastTranslator(CProtocolInet6Binder& aParent):

    35 	iParent(aParent)

    36 	{

    37 	}

    38 		

    39 CDHCPUnicastTranslator::~CDHCPUnicastTranslator()

    40 	{

    41 //	iParent.Unbind(this, 0);

    42 	}

    43 

    44 void CDHCPUnicastTranslator::FillIdentification(TServerProtocolDesc& anEntry)

    45 /**

    46  * Fills in an existing protocol description structure with details of this protocol.

    47  *

    48  * @param aProtocolDesc: reference to the structure to be filled in

    49  */

    50 	{

    51 	anEntry.iName=_S("dhcpunicasttranslator");

    52 	anEntry.iAddrFamily=KAfInet;

    53 	anEntry.iSockType=0;

    54 	anEntry.iProtocol=1; // not in a family so doesn't really matter

    55 	anEntry.iVersion=TVersion(1, 0, 0);

    56 	anEntry.iByteOrder=EBigEndian;

    57 	anEntry.iServiceInfo=0;

    58 	anEntry.iNamingServices=0;

    59 	anEntry.iSecurity=0;

    60 	anEntry.iMessageSize=0;

    61 	anEntry.iServiceTypeInfo=0;

    62 	anEntry.iNumSockets=0;

    63 	}

    64 

    65 

    66 void CDHCPUnicastTranslator::Identify(TServerProtocolDesc* aProtocolDesc) const

    67 /**

    68  * Fills in an existing protocol description structure with details of this protocol.

    69  *

    70  * @param aProtocolDesc: pointer to the structure to be filled in

    71  */

    72 	{

    73 	FillIdentification(*aProtocolDesc);

    74 	}

    75 

    76 

    77 

    78 /**

    79  * Incoming packet

    80  */

    81 TInt CDHCPUnicastTranslator::ApplyL(RMBufHookPacket& aPacket, RMBufRecvInfo& aInfo)

    82 	{

    83 

    84 	LOG	(

    85 		_LIT(KHookNotifyStr,"CDHCPUnicastTranslator::ApplyL hit with protocol: %d");

    86 		HookLog::Printf( KHookNotifyStr , aInfo.iProtocol );

    87 		)

    88 	

    89 	/** Fix for INC079832 - DHCP must be able to receive unicast replies from

    90 	 *   DHCP server (to an address that hasn't been set yet! chicken and egg).

    91 	 *

    92 	 *  Without this, a DHCP reply unicast to an address which isn't yet assigned

    93 	 *   to the inbound interface will be dropped.

    94 	 *

    95 	 *  So we need to detect BOOTP packets which are about to be dropped. This is

    96 	 *   done by installing this object as a "forwarding hook".

    97 	 *

    98 	 *  DHCP packets are detected as follows:

    99 	 *   - packet is UDP

   100 	 *   - UDP destination port is 0x0044

   101 	 *

   102 	 *  Modification is performed by setting dest address to broadcast address

   103 	 *   (and updating checksum)

   104 	 *

   105 	 *  Then we return KIp6Hook_DONE (which signals to the stack to re-inject

   106 	 *   the packet into the incoming data path).

   107 	 *

   108 	 *  Note: this trick isn't needed for IPv6 as link-local unicast is always

   109 	 *   possible before network/global address has been assigned.

   110 	 */

   111     if (aInfo.iVersion != 4 || aInfo.iProtocol != KProtocolInetUdp)

   112         return KIp6Hook_PASS;    // Only interested in IPv4 and UDP.

   113 

   114     TInetAddr&  dst = TInetAddr::Cast(aInfo.iDstAddr);

   115 

   116     if (!dst.IsUnicast())

   117         return KIp6Hook_PASS;    // Only the unicast case really needs fixing

   118 

   119     // Need to examine the UDP header

   120     TInet6Packet<TInet6HeaderUDP> udp(aPacket, aInfo.iOffset);

   121     if (udp.iHdr == NULL)

   122         return KIp6Hook_PASS;    // Oops, short packet, let someone else worry about it.

   123 

   124     // To cause least distruption, one could try to check that this really is

   125     // DCHP address configuration message with packet destination address

   126     // matching the offered address inside DCHP message (but this would need

   127     // more extensive packet snooping here)    

   128 #ifndef _DEBUG

   129     if (udp.iHdr->DstPort() == 68)

   130 #else

   131 	if (udp.iHdr->DstPort() == 68 || udp.iHdr->DstPort() == 127 || udp.iHdr->DstPort() == 119 || udp.iHdr->DstPort() == 125

   132 	#ifdef SYMBIAN_NETWORKING_DHCP_MSG_HEADERS

   133 	|| udp.iHdr->DstPort() == 92 || udp.iHdr->DstPort() == 99

   134 	#endif//SYMBIAN_NETWORKING_DHCP_MSG_HEADERS	

   135 	)	// debug mode, src port 127, 119, 125, 91, 98

   136 #endif

   137         {

   138         static const TIp6Addr broadcast = {{{0,0,0,0,0,0,0,0,0,0,0xff,0xff,255,255,255,255}}};

   139 

   140         dst.SetAddress(broadcast);

   141         udp.iHdr->SetChecksum(0);    // Either this or recompute the UDP checksum for broadcast address.

   142         return KIp6Hook_DONE;

   143         }

   144     return KIp6Hook_PASS;

   145 	}

   146 

   147