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1 // Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of the License "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // in_pkt.h - packet handling routines |
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15 // Generic packet handling utility for mapping packet handling to the RMBufChain. |
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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 @file in_pkt_partner.h |
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22 @publishedPartner |
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23 @released |
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24 */ |
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25 |
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26 #ifndef __IN_PKTPARTNER_H__ |
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27 #define __IN_PKTPARTNER_H__ |
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28 |
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29 #include <nifmbuf.h> |
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30 |
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31 // RMBufPacketPeek |
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32 // *************** |
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33 class RMBufPacketPeek : public RMBufChain |
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34 /** |
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35 Extends RMBufChain to add functions to read packet data as a descriptor |
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36 and as an IP header. |
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37 |
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38 The RMBufChain is assumed to contain the raw packet, without |
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39 the info block prepended (e.g. if this class is used for RMBufPacketBase |
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40 derived handle, it must be in "unpacked" state). |
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41 |
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42 @since v7.0 |
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43 @publishedAll |
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44 @released |
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45 */ |
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46 { |
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47 public: |
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48 IMPORT_C TPtr8 Access(TInt aSize, TUint aOffset = 0); |
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49 IMPORT_C TIpHeader *GetIpHeader(); |
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50 }; |
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51 |
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52 // TPacketHead |
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53 // *********** |
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54 class TPacketHead |
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55 /** |
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56 Storage for some precomputed information for an outbound packet flow. |
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57 |
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58 The outbound TPacketHead is part of the flow context (CFlowContext). |
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59 |
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60 The CFlowContext::Connect initializes the content from the parameters |
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61 of the flow (TFlowInfo) and runs the connection process.. The connection |
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62 process (MIp6Hook::OpenL and MFlowHook::ReadyL phases) completes the |
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63 information. After this, as long as the flow is connected, the content |
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64 is mostly frozen and <b>must not be modified by anyone</b>. |
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65 |
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66 When there is a need to change any flow information, the changes must |
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67 be done to the flow parameters (and not to TPacketHead). The change of |
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68 flow parameters also sets the CFlowContext::iChanged flag, and this |
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69 eventually causes a new CFlowContext::Connect, which re-initializes |
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70 the TPacketHead with the new information. |
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71 |
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72 For each field in the TPacketHead, the hook writer must follow the |
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73 basic rule (only for fields that it intends to change): |
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74 |
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75 - if some field is changed in MIp6Hook::OpenL, then the previous |
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76 value should be restored in the MFlowHook::ReadyL. |
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77 - an exeception: the hook must omit the restore, if the |
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78 previous value was unspecified value (for example, the source |
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79 address). |
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80 - the content of #iPacket (and #iOffset) are special: they cannot |
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81 be modified in the MIp6Hook::OpenL phase. A hook can |
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82 modify them only in the MFlowHook::ReadyL phase. And, if the hook |
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83 is adding an IP header for tunneling, it must save the current content |
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84 of these fields in the ReadyL function, and then clear out the fields |
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85 (it must make the iPacket empty and zero iOffset). The hook must add |
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86 the saved iPacket content below the added tunnel header in |
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87 MFlowHook::ApplyL . |
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88 |
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89 @since v7.0 |
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90 @publishedAll |
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91 @released |
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92 */ |
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93 { |
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94 public: |
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95 IMPORT_C TBool ExtHdrGet(TInt aType, TInt& aOfs, TInt& aLen); |
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96 IMPORT_C TBool ExtHdrGetOrPrependL(TInt aType, TInt& aOfs, TInt& aLen); |
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97 IMPORT_C TBool ExtHdrGetOrAppendL(TInt aType, TInt& aOfs, TInt& aLen); |
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98 IMPORT_C void AddDestinationOptionL(const TPtrC8& aOption, TUint8 aAlign=0, TUint8 aModulo=4); |
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99 IMPORT_C void AddDestinationOptionL(const TUint8* aOption, TUint8 aLen, TUint8 aAlign=0, TUint8 aModulo=4); |
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100 |
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101 public: |
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102 /** |
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103 "Virtual" IP header. The IPv6 header stucture is used, but the same |
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104 format is <b>also</b> used for the IPv4 destinations (Version() == 4, |
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105 even though the header format is still IPv6!) |
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106 |
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107 This header is initialized in the beginning of the OpenL phase |
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108 as follows: |
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109 @li Version = 0 |
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110 @li Traffic Class, copied from the flow iOptions.iTrafficClass |
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111 @li Flow Label = 0 |
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112 @li Payload Length = 0 (dummy field, not used) |
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113 @li Next Header, copied from the flow iProtocol |
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114 @li Hop Limit, copied from the flow iOptions.iHopLimit |
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115 @li Src Address, copied from the flow Local Address (usually unspecified) |
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116 @li Dst Address, copied from the flow Remote Address |
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117 |
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118 At beginning of the ReadyL phase (= at end of OpenL), the destination |
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119 address (and iDstId) are used to find a route on the interface. Depending |
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120 on whether this address is IPv4 (mapped) or IPv6, the Version field is set |
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121 accordingly to either 4 or 6. |
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122 |
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123 After succesfull completion of the ReadyL, this used for *each* packet |
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124 which needs an IP header to be generated on send. The Version() determines |
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125 whether IPv4 or IPv6 frame is to be generated (this is the initial |
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126 header in the packet, *before* running outbound ApplyL hooks): |
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127 |
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128 @verbatim |
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129 IPv6 IPv4 |
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130 Version == 6 ==4 |
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131 Traffic Class used as is used as TOS |
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132 Flow Label used as is ignored |
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133 Payload Length ignored ignored |
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134 Next Header used as is used as Protocol |
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135 Hop Limit used as is used as TTL |
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136 Src Address used as is used as IPv4 mapped |
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137 Dst Address used as is used as IPv4 mapped |
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138 @endverbatim |
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139 */ |
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140 TInet6HeaderIP ip6; |
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141 /** |
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142 Contains the scope id associated with the destination address |
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143 which is stored in #ip6 Dst Address. This id and address must |
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144 always be considered as a unit. Logically, any change changes |
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145 both values. |
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146 |
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147 iDstId is initialized from the flow context TFlowInfo::iRemote.Scope() at |
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148 beginning of the flow connect phase. If application does not define |
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149 this scope id, then the system will attempt to choose a default value |
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150 at beginning of the connect phase. If the default cannot be determined, |
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151 the flow is put into pending state (and no connect happens). |
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152 |
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153 @par MIp6Hook::OpenL |
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154 On entry to the OpenL, the iDstId is always non-zero and destination |
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155 address is specified. If a hook changes the destination address in |
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156 OpenL method, it must provide the correct id value |
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157 which goes with the new destination. If it cannot do this, it |
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158 must either abort the connect by leaving with an error state, or it |
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159 can leave with PENDING (> 0) status to signal there is no route |
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160 for the new destination. |
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161 If the stack cannot find suitable interface for the destination, then |
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162 it aborts the connect phase, and the flow is placed into holding state. |
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163 |
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164 @note |
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165 Only a tunneling hook can safely change the destination |
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166 address (a use of routing header can also be a kind of |
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167 tunneling). |
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168 |
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169 @par MFlowHook::ReadyL |
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170 If the hook changed the destination address (or id) in the OpenL, |
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171 the ReadyL must restore the original values back. |
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172 |
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173 */ |
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174 TUint32 iDstId; |
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175 /** |
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176 Contains the scope id associated with the source address |
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177 which is stored in #ip6 Src address. This is defined when the source |
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178 address is defined, and otherwise undefined. |
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179 |
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180 iSrcId is initialized from TFlowInfo::iLocal.Scope() at beginning of the |
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181 flow connect phase. If application defines the source address, |
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182 but does not specify this scope id, then the system chooses |
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183 the id based on the interface defined by the source address. |
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184 If scope and address are both specified, they must match the |
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185 selected interface. |
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186 |
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187 @par MIp6Hook::OpenL |
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188 On entry to the OpenL, the iSrcId (and source address) may be |
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189 undefined (#iSourceSet = 0). If defined (iSourceSet = 1), then |
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190 both address and iSrcId are defined (iSrcId != 0). A hook may |
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191 force a reselection of the source just by zeroing the |
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192 iSourceSet. |
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193 |
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194 @par MFlowHook::ReadyL |
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195 If the hook changed the source address (or id) in the OpenL, |
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196 the ReadyL must restore the original values back, but only |
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197 if the original value was defined (#iSourceSet = 1 in OpenL). |
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198 */ |
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199 TUint32 iSrcId; |
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200 /** |
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201 The source address has been set. |
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202 |
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203 This bit indicates whether the value stored in #ip6 src field |
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204 and #iSrcId is to be used as a source address as is. |
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205 |
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206 Initialized from TFlowInfo::iLocalSet, which tells whether user |
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207 specified tbe source address or not (e.g used RSocket Bind method). |
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208 The stack checks the value after each MIp6Hook::OpenL call, and |
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209 if the flag is set, the source in ip6 is used as is. If the flag |
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210 is zero, then the stack performs the normal source address selection |
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211 based on the current destination address (#iSrcId and destination |
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212 address). |
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213 |
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214 @par MIp6Hook::OpenL |
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215 On entry, this flag is always set and source address is defined. |
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216 A hook may clear this flag, if it wants the |
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217 stack choose the source address based on current destination. |
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218 The clearing operation is normally needed only by a tunneling |
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219 hook. |
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220 |
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221 @note |
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222 If the hook specifies the source address, it must be either |
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223 a valid source address for the interface or unspecified |
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224 address. |
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225 |
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226 @par MFlowHook::ReadyL |
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227 Upon entry to the ReadyL, the source address is always fully |
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228 known (the hook can assume that #iSrcId and the #ip6 source |
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229 addresses are valid). |
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230 If the source address was set before the OpenL, then this |
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231 must restore the original value (along with the #iSrcId |
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232 and source address). |
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233 */ |
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234 TUint iSourceSet:1; |
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235 #ifdef TPACKETHEAD_FRAGMENT |
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236 /** |
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237 The fragment processing alredy done. |
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238 |
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239 This bit is meaningful only in OpenL phase. If already set, |
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240 then some ealier hook has requested that the packet must |
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241 be fragmented to fit the mtu. |
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242 |
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243 A tunneling hook can set this bit in OpenL, if it needs |
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244 the fragmenting to happen before the ApplyL is called (e.g. |
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245 the fragments are tunneled instead of fragmenting the |
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246 tunneling). |
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247 |
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248 This bit can only be set or left as is. It cannot be cleared |
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249 once set. |
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250 */ |
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251 TUint iFragment:1; |
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252 #endif |
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253 /** |
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254 Selector info, the upper layer protocol. |
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255 |
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256 iProtocol has the same value as ip6.NextHeader() when iPacket is empty, |
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257 and otherwise it is the same as NextHeader() of the last extension |
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258 header in the iPacket. |
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259 |
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260 The values of the other selector fields: #iIcmpType, #iIcmpCode |
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261 #iSrcPort and #iDstPort depend on iProtocol. Whenever iProtocol |
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262 is changed, the other fields must be updated accordingly. |
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263 |
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264 @par MIp6Hook::OpenL |
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265 Because iPacket cannot be modified during the OpenL phase, the |
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266 content of this field and the Next Header (protocol) field in |
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267 the #ip6 pseudoheader must always be the same. This field should |
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268 be considered as <b>read-only</b>, unless the hook intends to |
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269 apply IP-in-IP tunneling, in which case the hook <b>must</b> |
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270 change the value to the appropriate tunneling protocol |
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271 (#KProtocolInet6Ipip or #KProtocolInetIpip). |
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272 |
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273 @par MFlowHook::ReadyL |
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274 Only a tunneling hook needs to restore the value here to match |
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275 the original upper layer protocol. See #iPacket for |
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276 more detailed information. |
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277 */ |
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278 TUint8 iProtocol; |
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279 /** |
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280 Selector field whose value depends on #iProtocol. |
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281 |
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282 If this field does not have meaning with the protocol, |
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283 the field content should be set to ZERO. |
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284 */ |
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285 TUint8 iIcmpType; |
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286 /** |
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287 Selector field whose value depends on #iProtocol. |
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288 |
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289 If this field does not have meaning with the protocol, |
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290 the field content should be set to ZERO. |
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291 */ |
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292 TUint8 iIcmpCode; |
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293 /** |
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294 Selector field whose value depends on #iProtocol. |
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295 |
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296 If this field does not have meaning with the protocol, |
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297 the field content should be set to ZERO. |
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298 */ |
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299 TUint16 iSrcPort; |
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300 /** |
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301 Selector field whose value depends on #iProtocol. |
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302 |
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303 If this field does not have meaning with the protocol, |
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304 the field content should be set to ZERO. |
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305 */ |
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306 TUint16 iDstPort; |
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307 /** |
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308 The amount of pre-computed IPv6 extension headers in iPacket which |
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309 are copied to the beginning of each outgoing packet |
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310 |
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311 If iOffset > 0, then #iPacket includes that much of extension |
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312 headers that are copied in front of each packet. |
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313 */ |
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314 TInt iOffset; |
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315 /** |
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316 Pre-computed extension headers for all packets in this flow. |
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317 |
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318 These can only be added in the ReadyL phase. If any of the |
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319 ReadyL's adds extension headers into this, it must take care |
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320 of maintaining the correct Next Header in the virtual IP header |
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321 (and the original upper layer protocol must be placed in the |
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322 next header of the last extension header added. |
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323 |
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324 Stack copies the content of this to each outgoing packet, just below |
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325 the IP header, before running the ApplyL functions of the outbound |
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326 flow hooks. |
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327 |
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328 @par MIp6Hook::OpenL |
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329 The iPacket <b>must not</b> be modified during the OpenL phase. |
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330 |
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331 @par MFlowHook::ReadyL |
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332 A non-tunneling hook may add extension headers into the current |
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333 iPacket. A tunneling hook has more complex requirements: |
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334 it must save the current iPacket and #iOffset and initialize |
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335 iOffset = 0, and iPacket as empty. |
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336 |
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337 @par MFlowHook::ApplyL |
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338 When a tunneling hook adds the tunneling IP header, it |
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339 must also copy the saved iPacket below the added IP header. |
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340 */ |
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341 RMBufPacketPeek iPacket; |
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342 /** |
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343 The received packet which caused an ICMP error reply to be sent. |
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344 |
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345 This is only used for ICMP error repply flows, and should be |
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346 ignored by others -- mainly for IPSEC hook. The packet, if |
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347 present, is in unpacked state. |
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348 */ |
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349 RMBufPacketBase iIcmp; |
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350 /** |
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351 The current destination interface. |
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352 |
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353 This is ONLY used during connect/OpenL phase. |
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354 |
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355 The value is maintained by the stack, and is intended as |
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356 read-only information for the hooks that have a use for |
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357 it (for example, IPSEC implementing VPN specific policies). |
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358 |
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359 A hook must not modify this value (the stack will recompute |
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360 the value after each OpenL, based on the possibly changed |
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361 address parameters in the TPacketHead) |
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362 |
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363 @par MIp6Hook::OpenL |
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364 <b>read-only</b> |
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365 @par MFlowHook::ReadyL |
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366 <b>read-only</b> |
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367 */ |
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368 TUint32 iInterfaceIndex; |
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369 }; |
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370 |
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371 // TPacketPoker |
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372 // ************ |
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373 class TPacketPoker |
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374 /** |
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375 Provides a utility for linear scanning of a chain of RMBuf objects (an RMBufChain). |
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376 |
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377 An object of this type maintains a current point in the RMBufChain. This point |
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378 can only move forward, and a leave occurs if the point advances beyond the |
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379 end of the chain. |
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380 |
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381 Any pointers and aligns arranged before the current point, remain valid: for |
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382 example, you can save a reference and advance the pointer, and the reference |
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383 remains usable. |
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384 |
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385 If instead you need to go to a single specified offset, then use |
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386 RMBufChain::Goto() or RMBufPacketPeek::Access(). |
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387 |
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388 @post |
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389 A Generic implementation assert: |
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390 after construct, iTail == 0 iff iCurrent == 0 (all scanned), or |
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391 in other words: as long as there are bytes after current point, |
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392 iTail will be non-zero (and More() returns ETrue). |
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393 All methods maintain this invariant or leave, if impossible. |
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394 |
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395 Some other utility methods, not directly related to scanning, are also included. |
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396 @since v7.0 |
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397 @publishedAll |
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398 @released |
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399 */ |
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400 { |
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401 public: |
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402 IMPORT_C TPacketPoker(RMBufChain &aChain); |
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403 |
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404 inline void SkipL(TInt aSize) |
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405 /** |
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406 Moves the current point forward a specified number of bytes. |
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407 |
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408 @param aSize Number of bytes to move forward |
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409 @leave KErrEof |
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410 if the request cannot be satisfied. |
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411 */ |
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412 { if (aSize < iTail) { iTail -= aSize; iOffset += aSize; } else OverL(aSize); } |
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413 |
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414 inline TUint8 *Ptr() const |
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415 /** |
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416 Raw pointer to the current point (can be invalid, if iTail = 0). |
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417 |
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418 @note Internal "unsafe" method |
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419 */ |
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420 {return iCurrent->Ptr() + iOffset; } |
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421 |
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422 inline TUint8 *ReferenceL(TInt aSize = 1) |
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423 /** |
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424 Gets a pointer to the current point, such that |
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425 at least the specified minimum number of bytes can be read. |
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426 |
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427 @param aSize |
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428 Specified minimum number of bytes to be read through |
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429 the returned pointer. |
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430 @return Raw data pointer |
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431 @leave KErrEof |
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432 if the request cannot be satisfied. |
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433 */ |
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434 { if (iTail >= aSize) return Ptr(); else return AdjustL(aSize); } |
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435 |
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436 inline TUint8 *ReferenceAndSkipL(TInt aSize) |
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437 /** |
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438 Gets a pointer to the current point, such that at least the |
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439 specified minimum number of bytes can be read, |
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440 and moves the point the specified number of bytes forward. |
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441 |
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442 @param aSize |
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443 Specified minimum number of bytes to be read through the returned |
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444 pointer, and the number of bytes to move forward |
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445 @return |
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446 Raw data pointer |
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447 @leave KErrEof |
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448 if the request cannot be satisfied. |
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449 */ |
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450 { TUint8 *x = ReferenceL(aSize); SkipL(aSize); return x; } |
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451 |
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452 inline TInt Remainder() const |
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453 /** |
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454 Gets the length of the contiguous space after the current point. |
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455 |
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456 @return Length after the current point |
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457 */ |
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458 { return iTail; } |
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459 |
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460 inline TBool AtBegin() const |
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461 /** |
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462 Tests whether the current point is at the beginning of an RMBuf. |
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463 |
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464 @return ETrue if current point is at the beginning |
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465 */ |
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466 { return iOffset == 0; } |
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467 |
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468 inline TBool More() const |
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469 /** |
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470 Tests whether there is more data to scan. |
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471 |
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472 @return ETrue if there is more data to scan |
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473 */ |
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474 { return iTail > 0; } |
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475 |
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476 IMPORT_C static TBool IsExtensionHeader(TInt aProtocolId); |
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477 private: |
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478 IMPORT_C void OverL(TInt aSize); |
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479 IMPORT_C TUint8 *AdjustL(TInt aSize); |
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480 /** The RMBuf of the current point. */ |
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481 RMBuf *iCurrent; |
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482 /** The offset of the current point in the RMBuf. */ |
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483 TInt iOffset; |
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484 /** Remaining bytes starting from the current point in the RMBuf. */ |
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485 TInt iTail; |
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486 }; |
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487 |
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488 #endif |