1 /*

     2 * Copyright (c) 2005 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

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

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:    implementation

    15 *

    16 */

    17 

    18 

    19 

    20 #include "tsrtpstreaminstatelatebind.h"

    21 #include "msrtpstreamincontext.h"

    22 #include "msrtpcryptohandlercontext.h"

    23 #include "msrtpcryptohandlercontextrtp.h"

    24 #include "msrtpcryptohandlercontextrtcp.h"

    25 #include "srtputils.h"

    26 

    27 // ----------------------------------------------------------------------------

    28 // TSRTPStreamInStateLateBind::TSRTPStreamInStateLateBind

    29 // ----------------------------------------------------------------------------

    30 //

    31 TSRTPStreamInStateLateBind::TSRTPStreamInStateLateBind(

    32     MSRTPStreamInContext& aStreamContext,

    33     MSRTPCryptoHandlerContextRTP& aCryptoHandlerRTPContext,

    34     MSRTPCryptoHandlerContextRTCP& aCryptoHandlerRTCPContext)

    35     : TSRTPStreamInStateBase(aStreamContext,

    36                             aCryptoHandlerRTPContext, 

    37                             aCryptoHandlerRTCPContext)

    38     {

    39     }

    40 

    41 // ----------------------------------------------------------------------------

    42 // TSRTPStreamInStateLateBind::DoUnprotectSrtpL

    43 // ----------------------------------------------------------------------------

    44 //		

    45 HBufC8* TSRTPStreamInStateLateBind::DoUnprotectSrtpL(const TDesC8& aPacket)

    46     {

    47     SRTP_DEBUG_DETAIL( "TSRTPStreamInStateLateBind::DoUnprotectSrtpL ENTRY");

    48    	SRTP_DEBUG_TINT_VALUE( "Encrypted PacketLength is", aPacket.Length() );                 

    49              

    50     // first initialize current encrypted RTP packet..

    51     iCryptoHandlerRTPContext.InitializeEncryptedPacketL(aPacket);    

    52     

    53     

    54     // for the first RTP packet, we need to set 

    55     // receiver s_l value to current sequence number, see RFC

    56     iCryptoHandlerRTPContext.SetReceiver_s_l();

    57        

    58     // Step 2 (in RFC 3711, section 3.3):

    59     // count the packet index i

    60     iCryptoHandlerRTPContext.CountReceiverPacketIndexL();

    61     

    62   	SRTP_DEBUG_DETAIL( "CheckMasterKeyIdentifier" );

    63     

    64     // check MKI if it is used

    65     iCryptoHandlerRTPContext.CheckMasterKeyIdentifierL();

    66    	

    67    	SRTP_DEBUG_DETAIL( "DeriveSessionKeysL" );

    68                   

    69     // derive session keys..

    70     iCryptoHandlerRTPContext.DeriveSessionKeysL();

    71 

    72     // do the replay protection, based on sender packetIndex 

    73     //note that in RCC mode, it set packet index as sender one

    74     iCryptoHandlerRTPContext.ReplayProtectionL();

    75     

    76     SRTP_DEBUG_DETAIL( "AuthenticateL" );

    77       

    78     // do the authentication (integrity check)

    79     iCryptoHandlerRTPContext.AuthenticateL();

    80                

    81     /*

    82     if "error in authentication"

    83         "clear Crypto Handler"

    84         go to the uninitialized state

    85     iStreamContext.ChangeRTPState(MSRTPStreamInContext::ESRTPStreamInUninitialized);    

    86     */

    87   	SRTP_DEBUG_DETAIL( "DecryptL" );

    88                     

    89      // step 6 decrypt..

    90     HBufC8* decryptedPacket = iCryptoHandlerRTPContext.DecryptL();

    91      

    92     // Step 7, conditional update s_l and ROC values..

    93     // (in RFC 3711, section 3.3):         

    94     iCryptoHandlerRTPContext.Update_s_l_and_RocL();

    95     iCryptoHandlerRTPContext.AddReplayIndex(); 

    96  

    97 

    98     // first RTP packet successfully decrypted..

    99     // session keys derived etc..

   100     // we can go to normal state

   101     SRTP_DEBUG_DETAIL( "ChangeStreamIn State to Normal" );

   102            

   103     

   104     iStreamContext.ChangeRTPState(MSRTPStreamInContext::ESRTPStreamInNormal);

   105     

   106     SRTP_DEBUG_TINT_VALUE( "the decrypted packet Length is", decryptedPacket->Length());            

   107         

   108     SRTP_DEBUG_DETAIL( "TSRTPStreamInStateLateBind::DoUnprotectSrtpL EXIT");

   109    	

   110     // return decrypted RTP packet

   111     return decryptedPacket;    

   112     

   113     }

   114 

   115 // ----------------------------------------------------------------------------

   116 // TSRTPStreamInStateLateBind::DoUnprotectSrtcpL

   117 // ----------------------------------------------------------------------------

   118 //		

   119 HBufC8* TSRTPStreamInStateLateBind::DoUnprotectSrtcpL(const TDesC8& aPacket)

   120     {

   121      // first initialize current encrypted RTP packet..

   122     iCryptoHandlerRTCPContext.InitializeEncryptedPacketL(aPacket);    

   123     

   124     

   125     //(in RFC 3711, section 3.4):

   126     // count the packet index i

   127     iCryptoHandlerRTCPContext.ReceiverPacketIndexL();

   128      

   129     // check MKI if it is used

   130     iCryptoHandlerRTCPContext.CheckMasterKeyIdentifierL();

   131      

   132     // derive session keys..

   133     iCryptoHandlerRTCPContext.DeriveSessionKeysL();

   134 

   135     // do the replay protection 

   136     iCryptoHandlerRTCPContext.ReplayProtectionL();

   137 

   138     // do the authentication (integrity check)

   139     iCryptoHandlerRTCPContext.AuthenticateL();

   140                

   141      // decrypt..

   142     HBufC8* decryptedPacket = iCryptoHandlerRTCPContext.DecryptL();

   143      

   144     iCryptoHandlerRTCPContext.AddReplayIndex(); 

   145     // first RTP packet successfully decrypted..

   146     // session keys derived etc..

   147     // we can go to normal state

   148     iStreamContext.ChangeRTCPState(MSRTPStreamInContext::ESRTPStreamInNormal);

   149     

   150     

   151     // return decrypted RTP packet

   152     return decryptedPacket;    

   153     }