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1 /* |
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2 * Copyright (c) 2004 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: . |
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15 * |
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16 */ |
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17 |
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18 |
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19 |
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20 |
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21 // INCLUDES |
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22 #include <e32std.h> |
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23 #include <e32math.h> |
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24 #include "srtpcryptohandler.h" |
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25 #include "srtpcryptohandlersrtcp.h" |
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26 #include "srtppacketrtcp.h" |
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27 #include "srtppacketsrtcp.h" |
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28 #include "msrtpcryptohandlercontext.h" |
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29 |
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30 #include "srtputils.h" |
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31 #include "srtpmasterkey.h" |
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32 #include "srtpmastersalt.h" |
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33 #include "msrtpkeyderivation.h" |
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34 #include "msrtpcipher.h" |
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35 #include "srtpstream.h" |
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36 #include "srtpcryptoparams.h" |
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37 #include "srtpcipher_aescm128.h" |
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38 #include "srtpcipher_null.h" |
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39 #include "srtpauthentication_hmac_sha1.h" |
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40 #include "srtpauthentication_null.h" |
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41 #include "srtpauthentication_rcc.h" |
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42 |
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43 // --------------------------------------------------------------------------- |
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44 // CSRTPCryptoHandlerSRTCP::CSRTPCryptoHandlerSRTCP |
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45 // --------------------------------------------------------------------------- |
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46 // |
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47 CSRTPCryptoHandlerSRTCP::CSRTPCryptoHandlerSRTCP( CSRTPStream& aStream) |
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48 : CSRTPCryptoHandler(aStream) |
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49 {} |
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50 |
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51 // --------------------------------------------------------------------------- |
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52 // Two-phased constructor. |
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53 // |
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54 // --------------------------------------------------------------------------- |
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55 // |
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56 CSRTPCryptoHandlerSRTCP* CSRTPCryptoHandlerSRTCP::NewL(CSRTPStream& aStream) |
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57 { |
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58 CSRTPCryptoHandlerSRTCP* self = CSRTPCryptoHandlerSRTCP::NewLC( aStream); |
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59 CleanupStack::Pop( self ); |
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60 return self; |
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61 } |
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62 |
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63 |
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64 // ----------------------------------------------------------------------------- |
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65 // CSRTPCryptoHandlerSRTCP::NewLC |
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66 // ----------------------------------------------------------------------------- |
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67 // |
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68 EXPORT_C CSRTPCryptoHandlerSRTCP* CSRTPCryptoHandlerSRTCP::NewLC( CSRTPStream& aStream) |
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69 { |
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70 CSRTPCryptoHandlerSRTCP* self = new( ELeave )CSRTPCryptoHandlerSRTCP( aStream); |
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71 CleanupStack::PushL( self ); |
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72 self->ConstructL(); |
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73 return self; |
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74 } |
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75 |
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76 // --------------------------------------------------------------------------- |
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77 // CSRTPCryptoHandlerSRTCP::~CSRTPCryptoHandlerSRTCP |
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78 // --------------------------------------------------------------------------- |
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79 // |
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80 CSRTPCryptoHandlerSRTCP::~CSRTPCryptoHandlerSRTCP( ) |
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81 { |
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82 |
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83 } |
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84 |
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85 |
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86 // --------------------------------------------------------------------------- |
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87 // CSRTPCryptoHandlerSRTCP::ConstructL() |
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88 // --------------------------------------------------------------------------- |
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89 // |
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90 void CSRTPCryptoHandlerSRTCP::ConstructL() |
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91 { |
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92 //construct the upper class |
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93 CSRTPCryptoHandler::ConstructL(); |
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94 SetEncAndAuthL(CryptoParams().iSrtcpEncAlg, |
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95 CryptoParams().iSrtcpAuthAlg); |
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96 iReplayPktIndex=0; |
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97 iReplayIndexDelta=0; |
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98 iSRTCPMasterKeyLifeTime = CryptoParams().iMasterKeysLifeTime; |
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99 |
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100 if ( !iSRTCPMasterKeyLifeTime || |
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101 iSRTCPMasterKeyLifeTime > KSRTCPMaterKeysLifeTime ) |
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102 { |
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103 iSRTCPMasterKeyLifeTime = KSRTCPMaterKeysLifeTime; |
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104 } |
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105 } |
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106 |
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107 // --------------------------------------------------------------------------- |
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108 // void CSRTPCryptoHandlerSRTCP::MasterKeysUpdated() |
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109 // --------------------------------------------------------------------------- |
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110 // |
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111 TBool CSRTPCryptoHandlerSRTCP::MasterKeysUpdated() |
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112 { |
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113 return iMasterDataUpdated; |
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114 |
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115 } |
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116 |
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117 |
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118 // --------------------------------------------------------------------------- |
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119 // void CSRTPCryptoHandlerSRTCP::CheckMasterKeyIdentifierL() |
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120 // --------------------------------------------------------------------------- |
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121 // |
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122 void CSRTPCryptoHandlerSRTCP::CheckMasterKeyIdentifierL() |
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123 { |
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124 // RFC 3711, section 3.4): |
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125 // verify that this packet uses the same MKI |
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126 // than we have in CryptoContext |
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127 if(Context().MasterKey().MKI()!= KNullDesC8) |
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128 { |
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129 if (Context().MasterKey().MKI().Length() > 0) |
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130 { |
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131 TPtrC8 mki = iCurrentPacket->MasterKeyIdentifier(); |
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132 if (Context().MasterKey().MKI().Compare(mki) != 0) |
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133 { |
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134 // we can not process this packet, since MKI does not match |
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135 User::Leave(KErrNotFound); |
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136 } |
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137 } |
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138 } |
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139 } |
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140 // --------------------------------------------------------------------------- |
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141 // void CSRTPCryptoHandlerSRTCP::AuthenticateL() |
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142 // --------------------------------------------------------------------------- |
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143 // |
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144 void CSRTPCryptoHandlerSRTCP::AuthenticateL() |
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145 { |
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146 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::AuthenticateL() entry" ); |
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147 if ( CryptoParams().iSrtcpAuthAlg != EAuthNull && |
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148 iCurrentPacket->AuthenticationTag().Length()==0) |
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149 { |
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150 User::Leave(KErrNotFound); |
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151 } |
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152 |
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153 if (iCurrentPacket->AuthenticationTag().Length()>0) |
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154 { |
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155 // calculate auth tag from the authenticated area.. |
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156 HBufC8* calculatedAuthTag = CalculateAuthTagL(); |
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157 CleanupStack::PushL(calculatedAuthTag); |
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158 SRTP_DEBUG_DETAIL( "SRTCP HMAC caculated Authentication tag" ); |
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159 SRTP_DEBUG_PACKET( *calculatedAuthTag ); |
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160 |
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161 // finally, compare the two auth tags.. |
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162 if (iCurrentPacket->AuthenticationTag().Compare( |
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163 *calculatedAuthTag) != 0) |
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164 { |
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165 // authentication failed, since tags dont match |
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166 SRTP_DEBUG_DETAIL( "authenticate tag is not match to caculated one" ); |
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167 User::Leave(KErrNotFound); |
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168 } |
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169 |
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170 // then, lose the auth tag we just calculated |
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171 CleanupStack::PopAndDestroy(calculatedAuthTag); |
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172 |
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173 } |
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174 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::AuthenticateL() exit" ); |
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175 } |
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176 |
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177 // --------------------------------------------------------------------------- |
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178 // CSRTPCryptoHandlerSRTCP::CountIV_And_TransformL() |
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179 // --------------------------------------------------------------------------- |
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180 // |
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181 HBufC8* CSRTPCryptoHandlerSRTCP::CountIV_And_TransformL() |
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182 { |
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183 /* |
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184 RTCP case is different. |
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185 */ |
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186 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::CountIV_And_TransformL entry" ); |
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187 //IV is 128 bit value |
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188 TBuf8<16> iv; |
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189 // set IV to be 128 bit, 16 octets |
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190 iv.SetLength(16); |
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191 |
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192 // count the IV for decryption |
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193 //RFC 3711 4.1.1 |
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194 TInt ret = TSRTPUtils::CountIV(iv, *iSessionSaltKey, SSRC(), iSRTCPIndexEStripped); |
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195 |
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196 SRTP_DEBUG_TUINT_VALUE( "SRTCP in ssrc" , SSRC()); |
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197 |
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198 if (ret!=KErrNone) |
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199 { |
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200 User::Leave(ret); |
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201 } |
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202 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::CountIV_And_TransformL exit" ); |
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203 |
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204 // Step 5, encryption (in RFC 3711, section 3.3): |
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205 return iCipher->TransformL( *iSessionEncrKey, |
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206 iv, iCurrentPacket->Payload() ); |
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207 } |
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208 |
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209 // --------------------------------------------------------------------------- |
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210 // CSRTPCryptoHandlerSRTCP::EncryptL() |
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211 // --------------------------------------------------------------------------- |
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212 // |
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213 HBufC8* CSRTPCryptoHandlerSRTCP::EncryptL() |
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214 { |
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215 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::EncryptL() entry" ); |
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216 |
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217 HBufC8* encryptedPayload = CountIV_And_TransformL(); |
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218 CleanupStack::PushL(encryptedPayload); |
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219 |
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220 TUint8* encryptedPayloadPtr = const_cast<TUint8*>(encryptedPayload->Des().Ptr()); |
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221 |
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222 HBufC8* srtpPacket = iCurrentPacket->CreateEncryptedPacketL(encryptedPayloadPtr); |
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223 CleanupStack::PushL(srtpPacket); |
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224 |
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225 TUint8* srtpPacketPtr = const_cast<TUint8*>(srtpPacket->Des().Ptr()); |
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226 |
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227 //Step 6, Add E flag and SRTCP Index (RFC 3711 section 3.4) |
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228 AddEflagAndSrtcpIndex(srtpPacketPtr); |
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229 //Step 7, Add MKI (in RFC 3711, section 3.3): |
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230 AddMKIToPacket(srtpPacketPtr); |
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231 |
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232 //Step 8, Add authentication tag (in RFC 3711, section 3.3): |
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233 AddAuthTagToPacketL(srtpPacketPtr); |
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234 |
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235 |
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236 CleanupStack::Pop(srtpPacket); |
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237 SRTP_DEBUG_DETAIL( "Encrypted Payload" ); |
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238 SRTP_DEBUG_PACKET( *encryptedPayload ); |
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239 |
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240 CleanupStack::PopAndDestroy(encryptedPayload); |
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241 iNumPackets++; |
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242 |
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243 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::EncryptL() exit" ); |
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244 |
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245 return srtpPacket; |
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246 } |
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247 |
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248 // --------------------------------------------------------------------------- |
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249 // CSRTPCryptoHandlerSRTCP::DecryptL() |
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250 // --------------------------------------------------------------------------- |
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251 // |
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252 HBufC8* CSRTPCryptoHandlerSRTCP::DecryptL() |
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253 { |
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254 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::DecryptL() entry" ); |
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255 // Step 6, decryption (in RFC 3711, section 3.3): |
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256 HBufC8* decryptedPayload = CountIV_And_TransformL(); |
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257 CleanupStack::PushL(decryptedPayload); |
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258 |
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259 TUint8* decryptedPayloadPtr = const_cast<TUint8*>(decryptedPayload->Des().Ptr()); |
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260 HBufC8* rtpPacket = iCurrentPacket->CreateDecryptedPacketL(decryptedPayloadPtr); |
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261 TUint8* rtpPacketPtr = const_cast<TUint8*>(rtpPacket->Des().Ptr()); |
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262 SRTP_DEBUG_DETAIL( "SRTCP Decrypt Payload" ); |
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263 SRTP_DEBUG_PACKET( *decryptedPayload ); |
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264 |
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265 CleanupStack::PopAndDestroy(decryptedPayload); |
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266 |
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267 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::DecryptL() exit" ); |
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268 |
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269 return rtpPacket; |
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270 } |
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271 |
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272 // --------------------------------------------------------------------------- |
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273 // CSRTPCryptoHandlerSRTCP::AddMKIToPacket |
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274 // |
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275 // --------------------------------------------------------------------------- |
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276 // |
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277 void CSRTPCryptoHandlerSRTCP::AddMKIToPacket(TUint8* aSrtpPacketPtr) |
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278 { |
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279 TUint8* ptr = aSrtpPacketPtr; |
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280 if( Context().MasterKey().MKI()!= KNullDesC8) |
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281 { |
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282 //Step 6, Add MKI (in RFC 3711, section 3.3): |
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283 if (Context().MasterKey().MKI().Length()>0 ) |
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284 { |
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285 ptr += iCurrentPacket->HeaderLength(); |
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286 ptr += iCurrentPacket->PayloadLength(); |
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287 ptr += KSRTCPPacketIndexLength4; |
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288 TUint8* mkiPtr = const_cast<TUint8*>(Context().MasterKey().MKI().Ptr()); |
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289 Mem::Copy( ptr, mkiPtr, Context().MasterKey().MKI().Length()); |
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290 } |
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291 } |
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292 } |
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293 // --------------------------------------------------------------------------- |
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294 // CSRTPCryptoHandlerSRTCP::AddAuthTagToPacketL |
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295 // |
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296 // --------------------------------------------------------------------------- |
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297 // |
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298 void CSRTPCryptoHandlerSRTCP::AddAuthTagToPacketL(TUint8* aSrtpPacketPtr) |
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299 { |
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300 TUint8* ptr = aSrtpPacketPtr; |
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301 |
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302 //Step 7, Add authentication tag (in RFC 3711, section 3.3): |
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303 if ( CryptoParams().iSrtcpAuthTagLen>0) |
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304 { |
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305 ptr += iCurrentPacket->HeaderLength(); |
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306 ptr += iCurrentPacket->PayloadLength(); |
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307 ptr += KSRTCPPacketIndexLength4 ; /*srtcp index length*/ |
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308 if(Context().MasterKey().MKI()!= KNullDesC8) |
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309 { |
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310 ptr += Context().MasterKey().MKI().Length(); |
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311 } |
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312 //Copy the authenticatin portion only not with MKI key part |
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313 //RFC 3711 3.4 SRCP authentication portion including index |
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314 TInt len= iCurrentPacket->HeaderLength() + iCurrentPacket->PayloadLength() |
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315 + KSRTCPPacketIndexLength4 /*SRTCP index length*/; |
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316 HBufC8* authPortion = HBufC8::NewMaxLC(len); |
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317 TUint8* authptr = const_cast<TUint8*>(authPortion->Des().Ptr()); |
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318 Mem::Copy( authptr, aSrtpPacketPtr, len); |
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319 authPortion->Des().SetLength(len); |
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320 |
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321 HBufC8* authTag = DoAuthenticationL(*authPortion, KNullDesC8); |
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322 |
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323 |
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324 CleanupStack::PopAndDestroy( authPortion ); |
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325 authPortion=NULL; |
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326 |
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327 |
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328 Mem::Copy( ptr, authTag->Ptr(), authTag->Length()); |
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329 delete authTag; |
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330 authTag=NULL; |
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331 } |
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332 } |
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333 // --------------------------------------------------------------------------- |
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334 // CSRTPCryptoHandlerSRTCP::CalculateAuthTagL() |
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335 // --------------------------------------------------------------------------- |
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336 // |
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337 HBufC8* CSRTPCryptoHandlerSRTCP::CalculateAuthTagL() |
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338 { |
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339 //RFC 3711 3.4 SRCP authentication portion including index |
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340 // that is, M = header + payload (Report block) + SRTCP indexp |
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341 |
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342 // calculate auth tag from the authenticated area.. |
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343 |
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344 TInt len= iCurrentPacket->HeaderLength() + |
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345 iCurrentPacket->PayloadLength() +4; /*SRTCP index length*/ |
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346 HBufC8* authPortion = iCurrentPacket->Get_Concatenated_MDataL(ETrue); |
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347 CleanupStack::PushL( authPortion ); |
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348 authPortion->Des().SetLength(len); |
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349 |
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350 HBufC8* calculatedAuthTag = DoAuthenticationL(*authPortion, KNullDesC8); |
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351 |
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352 // then, lose authPortion buffer |
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353 |
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354 CleanupStack::PopAndDestroy( authPortion ); |
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355 authPortion= NULL; |
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356 |
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357 return calculatedAuthTag; |
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358 } |
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359 |
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360 // --------------------------------------------------------------------------- |
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361 // CSRTPCryptoHandlerSRTCP::DoAuthenticationL |
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362 // |
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363 // --------------------------------------------------------------------------- |
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364 // |
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365 HBufC8* CSRTPCryptoHandlerSRTCP::DoAuthenticationL(const TDesC8& aAuthenticatedArea, |
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366 const TDesC8& aRoc) |
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367 { |
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368 // calculate auth tag from the authenticated area.. |
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369 TUint authtaglen= CryptoParams().iSrtcpAuthTagLen; |
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370 // Note that RCCm3 work as Auth Null so taglen does not matter to RTP/RTCP |
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371 if (aRoc.Length() && |
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372 (CryptoParams().iSrtcpAuthAlg == EAuthRCCm1 || |
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373 CryptoParams().iSrtcpAuthAlg == EAuthRCCm2 )) |
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374 { |
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375 authtaglen-= KSRTPAuthTagLength32 ; |
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376 } |
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377 if ((!aRoc.Length()) && |
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378 ( CryptoParams().iSrtcpAuthAlg != EAuthNull && |
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379 CryptoParams().iSrtcpAuthAlg != EAuthHMAC_SHA1)) |
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380 { |
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381 //This is for RTCP if using RCC mode because currently handler sharing |
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382 //the same context |
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383 authtaglen=KSRTPAuthTagDefaultLength; |
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384 } |
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385 return iAuthenticator->AuthenticateL(authtaglen, |
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386 *iSessionAuthKey, |
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387 aAuthenticatedArea, |
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388 aRoc); |
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389 } |
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390 |
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391 // --------------------------------------------------------------------------- |
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392 // void CSRTPCryptoHandlerSRTCP::InitializePlainPacketL() |
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393 // --------------------------------------------------------------------------- |
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394 // |
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395 void CSRTPCryptoHandlerSRTCP::InitializePlainPacketL(const TDesC8& aPacket) |
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396 { |
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397 if(iCurrentPacket) |
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398 delete iCurrentPacket;iCurrentPacket = NULL; |
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399 iCurrentPacket = CSRTPPacketRTCP::NewL(aPacket, *this); |
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400 } |
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401 |
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402 // --------------------------------------------------------------------------- |
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403 // void CSRTPCryptoHandlerSRTCP::InitializeEncryptedPacketL() |
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404 // --------------------------------------------------------------------------- |
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405 // |
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406 void CSRTPCryptoHandlerSRTCP::InitializeEncryptedPacketL(const TDesC8& aPacket) |
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407 { |
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408 if(iCurrentPacket) |
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409 delete iCurrentPacket;iCurrentPacket = NULL; |
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410 iCurrentPacket = CSRTPPacketSRTCP::NewL(aPacket, *this); |
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411 } |
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412 |
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413 // --------------------------------------------------------------------------- |
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414 // CSRTPCryptoHandlerSRTCP::DeriveSessionKeysL() |
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415 // --------------------------------------------------------------------------- |
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416 // |
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417 void CSRTPCryptoHandlerSRTCP::DeriveSessionKeysL() |
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418 { |
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419 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::DeriveSessionKeysL() Entry" ); |
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420 |
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421 TBuf8<100> sessionKey_X; |
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422 DeleteSessionKeys(); |
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423 |
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424 TUint64 r = TSRTPUtils::Cnt_r(iSRTCPIndexEStripped, |
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425 CryptoParams().iSrtcpKeyDervRate); |
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426 |
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427 // session encryption key |
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428 //sessionKey_X.SetLength(Context()->MasterKey().EncrKeyLength()); |
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429 sessionKey_X.SetLength(100); |
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430 // session encryption key derivation : |
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431 sessionKey_X.FillZ(); |
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432 Count_X(r, KSRTCPEncryptionLabel, KSRTPIndexLength, sessionKey_X); |
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433 iSessionEncrKey = iKeyDeriver->PRF_128BitL(Context().MasterKey().EncrKeyLength(), |
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434 Context().MasterKey().MasterKey(), |
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435 sessionKey_X); |
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436 SRTP_DEBUG_DETAIL( "SRTCP iSessionEncrKey as CipherKey " ); |
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437 SRTP_DEBUG_PACKET( *iSessionEncrKey ); |
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438 |
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439 // session authentication key |
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440 sessionKey_X.FillZ(); |
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441 //sessionKey_X.SetLength(Context()->MasterKey().AuthKeyLength()); |
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442 Count_X(r, KSRTCPAuthenticationLabel, KSRTPIndexLength, sessionKey_X); |
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443 iSessionAuthKey = iKeyDeriver->PRF_128BitL(Context().MasterKey().AuthKeyLength(), |
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444 Context().MasterKey().MasterKey(), |
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445 sessionKey_X); |
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446 |
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447 SRTP_DEBUG_DETAIL( "SRTCP iSessionAuthKey" ); |
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448 SRTP_DEBUG_PACKET( *iSessionAuthKey); |
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449 |
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450 // session salt key |
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451 sessionKey_X.FillZ(); |
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452 //sessionKey_X.SetLength(Context()->MasterSalt().SaltLength()); |
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453 Count_X(r, KSRTCPSaltingLabel, KSRTPIndexLength, sessionKey_X); |
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454 iSessionSaltKey = iKeyDeriver->PRF_128BitL(Context().MasterSalt().SaltLength(), |
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455 Context().MasterKey().MasterKey(), |
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456 sessionKey_X); |
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457 SRTP_DEBUG_DETAIL( "SRTCP iSessionSaltKey" ); |
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458 SRTP_DEBUG_PACKET( *iSessionSaltKey ); |
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459 |
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460 |
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461 iMasterDataUpdated = EFalse; |
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462 SRTP_DEBUG_DETAIL( "CSRTPCryptoHandlerSRTCP::DeriveSessionKeysL() Exit" ); |
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463 |
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464 } |
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465 |
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466 |
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467 // --------------------------------------------------------------------------- |
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468 // CSRTPCryptoHandlerSRTCP::StripEBit() |
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469 // --------------------------------------------------------------------------- |
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470 // |
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471 void CSRTPCryptoHandlerSRTCP::StripEBit() |
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472 { |
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473 // strip the Ebit away |
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474 iSRTCPIndexEStripped = iSRTCPIndex ^ 0x80000000; |
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475 } |
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476 |
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477 |
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478 // --------------------------------------------------------------------------- |
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479 // void CSRTPCryptoHandlerSRTCP::ReplayProtectionL() |
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480 // --------------------------------------------------------------------------- |
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481 // |
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482 void CSRTPCryptoHandlerSRTCP::ReplayProtectionL() |
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483 { |
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484 if ( CryptoParams().iSrtcpReplayProtection) |
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485 { |
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486 TInt delta =0; |
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487 delta= iSRTCPIndexEStripped/*updated one*/ - iReplayPktIndex; //set as 0 |
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488 |
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489 //Index check |
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490 if ( CryptoParams().iSrtcpReplayProtection) |
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491 { |
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492 User::LeaveIfError (ReplayCheck(delta)); |
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493 } |
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494 //if the index is inside the replay window and index does not appear in rdb |
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495 //then Index add after authentication passed |
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496 iReplayIndexDelta= delta; |
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497 } |
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498 } |
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499 |
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500 // --------------------------------------------------------------------------- |
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501 // CSRTPCryptoHandlerSRTCP::CountSenderPacketIndex() |
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502 // --------------------------------------------------------------------------- |
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503 // |
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504 void CSRTPCryptoHandlerSRTCP::CountSenderPacketIndexL() |
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505 { |
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506 //Re-Key was needed earlier but key has not yet been updated |
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507 //iReKey is false |
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508 //Call it after each packet has been sent |
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509 //TReal modulus(0x10000000); |
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510 TReal twoexp31= 0x80000000; |
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511 |
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512 TReal srtcpindexincremented= iSRTCPIndexEStripped+1; |
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513 TReal result; |
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514 TInt32 intResult; |
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515 // count (ROC - 1) mod 2^31 |
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516 |
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517 TInt res = Math::Mod(result, srtcpindexincremented, twoexp31); |
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518 if (res!=KErrNone) |
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519 { |
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520 User::Leave(res); |
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521 } |
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522 |
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523 intResult = (TUint)result; |
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524 |
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525 iSRTCPIndexEStripped = intResult; |
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526 // E bit set to 1 indicates encrpted pacet 0 otherwise |
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527 iSRTCPIndex =0x00000000; |
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528 if (CryptoParams().iSrtcpEncAlg!=ENullAlg) |
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529 { |
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530 iSRTCPIndex =0x80000000; |
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531 } |
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532 |
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533 iSRTCPIndex = iSRTCPIndex + iSRTCPIndexEStripped; |
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534 iCurrentPacket->SetPacketIndex(iSRTCPIndex); |
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535 //Checking next Index if Keys needed to be renew |
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536 IndexReKeyCheckL(); |
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537 } |
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538 |
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539 // --------------------------------------------------------------------------- |
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540 // CSRTPCryptoHandlerSRTCP::ReceiverPacketIndexL() |
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541 // --------------------------------------------------------------------------- |
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542 // |
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543 void CSRTPCryptoHandlerSRTCP::ReceiverPacketIndexL() |
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544 { |
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545 if (iReKey) |
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546 { |
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547 //Re-Key was needed earlier but key has not yet been updated |
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548 User::Leave(KErrTooBig); |
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549 } |
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550 /* Can be done in the Replay protection |
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551 if (iCurrentPacket->PacketIndex()<iSRTCPIndex) |
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552 { |
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553 //the receiver packet index is samller than the earlier packet index |
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554 //ignore this packet by leave |
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555 User::Leave(KErrCorrupt); |
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556 }*/ |
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557 //Updated the packet index during the construction of Packet |
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558 iSRTCPIndex = iCurrentPacket->PacketIndex(); |
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559 //Strip EBit only when the encAlg is not NULL |
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560 if (CryptoParams().iSrtcpEncAlg!=ENullAlg) |
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561 StripEBit(); |
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562 IndexReKeyCheckL(); |
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563 } |
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564 // --------------------------------------------------------------------------- |
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565 // CSRTPCryptoHandlerSRTCP::InitialPacketIndex() |
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566 // --------------------------------------------------------------------------- |
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567 // |
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568 void CSRTPCryptoHandlerSRTCP::InitialPacketIndex() |
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569 { |
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570 //iSRTCPIndexEStripped=0x00; |
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571 iSRTCPIndex =0x80000000; |
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572 StripEBit(); |
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573 iSRTCPIndex = iSRTCPIndex + iSRTCPIndexEStripped; |
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574 iCurrentPacket->SetPacketIndex(iSRTCPIndex); |
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575 } |
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576 |
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577 // --------------------------------------------------------------------------- |
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578 // CSRTPCryptoHandlerSRTCP::AddEflagAndSrtcpIndex() |
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579 // --------------------------------------------------------------------------- |
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580 // |
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581 void CSRTPCryptoHandlerSRTCP::AddEflagAndSrtcpIndex(TUint8* aSrtcpPacketPtr) |
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582 { |
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583 //EBit set to 1 as hardcoded |
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584 |
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585 TUint8* ptr = aSrtcpPacketPtr; |
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586 |
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587 //Step 6, Add E flag and SRTCP Index (RFC 3711 section 3.4) |
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588 |
|
589 ptr += iCurrentPacket->HeaderLength(); |
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590 ptr += iCurrentPacket->PayloadLength(); |
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591 //EBit set to 1 indicates encryted packet, otherwise set to 0 |
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592 if (CryptoParams().iSrtcpEncAlg!=ENullAlg ) |
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593 { |
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594 TSRTPUtils::Write32( ptr, iSRTCPIndex ); |
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595 } |
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596 else |
|
597 { |
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598 TSRTPUtils::Write32( ptr, iSRTCPIndexEStripped); |
|
599 } |
|
600 |
|
601 } |
|
602 // --------------------------------------------------------------------------- |
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603 // CSRTPCryptoHandlerSRTCP::IndexReKeyCheck() |
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604 // --------------------------------------------------------------------------- |
|
605 // |
|
606 void CSRTPCryptoHandlerSRTCP::IndexReKeyCheckL() |
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607 { |
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608 TReal twoexp31= 0x80000000; |
|
609 |
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610 TReal srtcpIndexIncremented= iSRTCPIndexEStripped+1; |
|
611 TReal remainder; |
|
612 |
|
613 |
|
614 |
|
615 TInt res = Math::Mod(remainder, srtcpIndexIncremented, twoexp31); |
|
616 if (res!=KErrNone) |
|
617 { |
|
618 User::Leave(res); |
|
619 } |
|
620 if (remainder == 0.0 && iSRTCPIndexEStripped != 0) |
|
621 { |
|
622 //RFC 3711 8.1 & 9.2 |
|
623 iReKey = ETrue; |
|
624 iStream.KeyExpired(); |
|
625 //called incase the packets index is big in the begining |
|
626 iStream.ReKeyNeeded(); |
|
627 } |
|
628 //should create function for checking.when value is bigger |
|
629 TUint64 reKeyNumPacket = iNumPackets + KLeftNumOfPacketBeforeReKey; |
|
630 // Re-key only call one time when there are 100 number packets left to send/recv |
|
631 if ( ( reKeyNumPacket ) == iSRTCPMasterKeyLifeTime ) |
|
632 { |
|
633 iStream.ReKeyNeeded(); |
|
634 } |
|
635 //Key is really expired |
|
636 if ( iNumPackets >= iSRTCPMasterKeyLifeTime ) |
|
637 { |
|
638 iReKey = ETrue; |
|
639 iStream.KeyExpired(); |
|
640 } |
|
641 } |
|
642 |
|
643 // --------------------------------------------------------------------------- |
|
644 // CSRTPCryptoHandlerSRTCP::AddReplayIndex() |
|
645 // --------------------------------------------------------------------------- |
|
646 // |
|
647 void CSRTPCryptoHandlerSRTCP::AddReplayIndex() |
|
648 { |
|
649 if (CryptoParams().iSrtcpReplayProtection) |
|
650 { |
|
651 if (iReplayIndexDelta > 0) |
|
652 { |
|
653 /* shift forward by delta */ |
|
654 iReplayPktIndex = iSRTCPIndexEStripped; |
|
655 } |
|
656 else |
|
657 { |
|
658 /* delta is in window, so flip bit in bitmask */ |
|
659 /* mark as seen */ |
|
660 TInt diff= -(iReplayIndexDelta); |
|
661 iBitmap |= ((TUint64)1 << diff); |
|
662 } |
|
663 /* note that we need not consider the case that delta == 0 */ |
|
664 } |
|
665 //Add Number of packets received |
|
666 iNumPackets++; |
|
667 } |