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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: SRTP-specific packet handling routines. |
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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 "srtppacketsrtp.h" |
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23 #include "srtpcryptohandler.h" |
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24 #include "srtpcryptocontext.h" |
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25 #include "srtpmasterkey.h" |
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26 #include "srtpmastersalt.h" |
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27 #include "srtputils.h" |
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28 |
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29 _LIT8( KMKINULL, "NULL"); |
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30 |
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31 // ----------------------------------------------------------------------------- |
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32 // CSRTPPacketSRTP::CSRTPPacketSRTP |
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33 // ----------------------------------------------------------------------------- |
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34 // |
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35 CSRTPPacketSRTP::CSRTPPacketSRTP(const TDesC8& aPacket, |
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36 CSRTPCryptoHandler& aHandler) |
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37 : CSRTPPacketRTP(aPacket, aHandler), |
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38 iAuthenticationTag(TPtrC8()), |
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39 iMasterKeyIdentifier(TPtrC8()) |
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40 { |
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41 |
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42 } |
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43 |
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44 // ----------------------------------------------------------------------------- |
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45 // CSRTPPacketSRTP::~CSRTPPacketSRTP |
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46 // ----------------------------------------------------------------------------- |
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47 // |
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48 CSRTPPacketSRTP::~CSRTPPacketSRTP() |
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49 { |
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50 |
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51 } |
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52 |
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53 // --------------------------------------------------------------------------- |
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54 // Two-phased constructor. |
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55 // |
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56 // --------------------------------------------------------------------------- |
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57 // |
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58 CSRTPPacketSRTP* CSRTPPacketSRTP::NewL(const TDesC8& aPacket, |
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59 CSRTPCryptoHandler& aHandler) |
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60 { |
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61 CSRTPPacketSRTP* self = new( ELeave )CSRTPPacketSRTP( aPacket, aHandler); |
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62 CleanupStack::PushL( self ); |
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63 self->ConstructL(); |
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64 CleanupStack::Pop( self ); |
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65 return self; |
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66 } |
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67 |
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68 // ----------------------------------------------------------------------------- |
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69 // void CSRTPPacketSRTP::ConstructL |
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70 // ----------------------------------------------------------------------------- |
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71 // |
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72 void CSRTPPacketSRTP::ConstructL() |
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73 { |
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74 CSRTPPacketRTP::ConstructL(); |
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75 UpdatePayloadLengthL(); |
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76 SRTP_DEBUG_TINT_VALUE( "SRTP payload length", iPayloadLength ); |
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77 |
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78 UpdatePayload(); |
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79 UpdateAuthenticationTagL(); |
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80 UpdateMasterKeyIdentifier(); |
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81 } |
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82 |
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83 // --------------------------------------------------------------------------- |
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84 // CSRTPPacketSRTP::AuthenticationTag() |
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85 // --------------------------------------------------------------------------- |
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86 // |
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87 TPtrC8 CSRTPPacketSRTP::AuthenticationTag() |
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88 { |
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89 SRTP_DEBUG_DETAIL( "SRTP HMAC authen tag and the tag in the packet" ); |
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90 SRTP_DEBUG_PACKET( iAuthenticationTag ); |
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91 |
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92 return iAuthenticationTag; |
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93 } |
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94 |
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95 |
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96 // --------------------------------------------------------------------------- |
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97 // CSRTPPacketSRTP::MasterKeyIdentifier() |
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98 // --------------------------------------------------------------------------- |
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99 // |
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100 TPtrC8 CSRTPPacketSRTP::MasterKeyIdentifier() |
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101 { |
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102 return iMasterKeyIdentifier; |
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103 } |
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104 |
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105 // --------------------------------------------------------------------------- |
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106 // CSRTPPacketSRTP::UpdatePayloadLengthL() |
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107 // --------------------------------------------------------------------------- |
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108 // |
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109 void CSRTPPacketSRTP::UpdatePayloadLengthL() |
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110 { |
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111 SRTP_DEBUG_DETAIL( "CSRTPPacketSRTP::UpdatePayloadLengthL ENTRY" ); |
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112 |
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113 // the real RTP packet length is |
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114 // the packet size - header - MKI - Auth tag |
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115 // Need implementation of caculating RCC |
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116 // when RCC is not included but the tag length is 14 or 8 |
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117 TUint rocLength=KSRTPROCLength4; |
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118 TUint authTagLen=0; |
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119 authTagLen = iHandler.Context().CryptoParams().iSrtpAuthTagLen/8; |
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120 if (!TagWithROCLengthL() && ( |
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121 iHandler.Context().CryptoParams().iSrtpAuthAlg == EAuthRCCm2 || |
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122 iHandler.Context().CryptoParams().iSrtpAuthAlg == EAuthRCCm3)) |
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123 { |
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124 authTagLen -= rocLength; |
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125 } |
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126 if (!TagWithROCLengthL() && ( |
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127 iHandler.Context().CryptoParams().iSrtpAuthAlg == EAuthRCCm1)) |
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128 { |
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129 authTagLen=0; |
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130 } |
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131 TUint deductedLen = HeaderLength() + iHandler.Context().MasterKey().MKI().Length() + authTagLen; |
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132 |
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133 iPayloadLength = iPacket.Length() - deductedLen; |
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134 if ( iPacket.Length() <= HeaderLength() ) |
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135 { |
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136 iPayloadLength = 0; |
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137 } |
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138 SRTP_DEBUG_TINT_VALUE( "SRTP payload length", iPayloadLength); |
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139 SRTP_DEBUG_DETAIL( "CSRTPPacketSRTP::UpdatePayloadLengthL EXIT" ); |
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140 } |
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141 |
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142 |
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143 // --------------------------------------------------------------------------- |
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144 // CSRTPPacketSRTP::CountDecryptedPacketSize() |
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145 // --------------------------------------------------------------------------- |
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146 // |
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147 TUint CSRTPPacketSRTP::CountDecryptedPacketSize() |
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148 { |
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149 return iHeaderLength + iPayloadLength; |
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150 } |
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151 |
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152 // --------------------------------------------------------------------------- |
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153 // CSRTPPacketSRTP::CreateDecryptedPacketL() |
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154 // --------------------------------------------------------------------------- |
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155 // |
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156 HBufC8* CSRTPPacketSRTP::CreateDecryptedPacketL(TUint8* aDecryptedPayloadPtr) |
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157 { |
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158 // create decrypted RTP packet |
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159 // first count needed packet size |
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160 TUint rtpPacketSize = CountDecryptedPacketSize(); |
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161 |
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162 return CopyHeaderAndPayloadL(rtpPacketSize, aDecryptedPayloadPtr); |
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163 |
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164 } |
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165 |
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166 // --------------------------------------------------------------------------- |
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167 // CSRTPPacketSRTP::UpdateAuthenticationTag() |
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168 // --------------------------------------------------------------------------- |
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169 // |
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170 void CSRTPPacketSRTP::UpdateAuthenticationTagL() |
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171 { |
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172 //Here means MAC part |
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173 TPtrC8 authTag = GetAuthenticationTagL(); |
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174 if (authTag.Compare(KNullDesC8)) |
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175 { |
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176 iAuthenticationTag.Set(authTag.Ptr(), authTag.Length()); |
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177 } |
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178 } |
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179 |
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180 // --------------------------------------------------------------------------- |
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181 // CSRTPPacketSRTP::GetAuthenticationTag() |
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182 // --------------------------------------------------------------------------- |
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183 // |
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184 TPtrC8 CSRTPPacketSRTP::GetAuthenticationTagL() |
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185 { |
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186 if ((iHandler.Context().CryptoParams().iSrtpAuthTagLen > 0) && |
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187 iHandler.Context().CryptoParams().iSrtpAuthAlg == EAuthHMAC_SHA1) |
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188 { |
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189 TUint authTagLength = iHandler.Context().CryptoParams().iSrtpAuthTagLen; |
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190 TUint authTagLenInBytes = authTagLength/8; |
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191 TUint packetLength = iPacket.Length(); |
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192 TUint position = packetLength - authTagLenInBytes; |
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193 |
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194 return iPacket.Mid(position,authTagLenInBytes); |
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195 } |
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196 if ((iHandler.Context().CryptoParams().iSrtpAuthTagLen > 0) && |
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197 ((iHandler.Context().CryptoParams().iSrtpAuthAlg == EAuthRCCm1 && |
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198 TagWithROCLengthL()) || |
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199 iHandler.Context().CryptoParams().iSrtpAuthAlg == EAuthRCCm2)) |
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200 { |
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201 TUint authTagLength = iHandler.Context().CryptoParams().iSrtpAuthTagLen; |
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202 TUint authTagLenInBytes = authTagLength/8;//14 |
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203 //Here we only need MAC part |
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204 authTagLenInBytes-= 4; |
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205 TUint packetLength = iPacket.Length(); |
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206 TUint position = packetLength - authTagLenInBytes; |
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207 |
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208 return iPacket.Mid(position,authTagLenInBytes); |
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209 } |
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210 // in case of EAuthRCCm3 and EAuthNULL |
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211 TPtrC8 authTagNull(KNullDesC8); |
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212 return authTagNull; |
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213 } |
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214 |
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215 // --------------------------------------------------------------------------- |
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216 // CSRTPPacketSRTP::GetMasterKeyIdentifier() |
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217 // --------------------------------------------------------------------------- |
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218 // |
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219 TPtrC8 CSRTPPacketSRTP::GetMasterKeyIdentifier() |
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220 { |
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221 if(iHandler.Context().MasterKey().MKI()!= KNullDesC8) |
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222 { |
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223 TInt mkiLength = iHandler.Context().MasterKey().MKI().Length(); |
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224 if (iHandler.Context().MasterKey().MKI().Length() > 0) |
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225 { |
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226 TUint authTagLength = iHandler.Context().CryptoParams().iSrtpAuthTagLen; |
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227 TUint authTagLenInBytes = authTagLength/8; |
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228 TUint position = iPacket.Length() - authTagLenInBytes - mkiLength; |
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229 |
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230 return iPacket.Mid(position,mkiLength); |
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231 } |
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232 } |
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233 TPtrC8 mkiNull( KMKINULL ); |
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234 return mkiNull; |
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235 } |
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236 |
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237 // --------------------------------------------------------------------------- |
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238 // CSRTPPacketSRTP::UpdateMasterKeyIdentifierL() |
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239 // --------------------------------------------------------------------------- |
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240 // |
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241 void CSRTPPacketSRTP::UpdateMasterKeyIdentifier() |
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242 { |
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243 TPtrC8 mki = GetMasterKeyIdentifier(); |
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244 if (mki.Compare( KMKINULL )) |
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245 { |
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246 iMasterKeyIdentifier.Set(mki.Ptr(),mki.Length()); |
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247 } |
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248 } |
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249 |