Writing an Outflow Hook Tutorial

This topic describes how to write an outflow hook.

1. The CIp6Hook() is a base class for all hook protocols.
2. 
   The OpenL() function is used to open a hook for a data flow
3. 
   The following are the parameters of OpenL() function:
   1. 
      aHead – Contains the address information of the flow
   2. 
      aFlow – Flow for the active hook
4. 
   The ReadyL() function sets the data packet in a ready state.
5. 
   The IP protocol calls the ApplyL() function to create an outflow hook. The following are the parameters of an ApplyL() function:
   1. 
      aPacket – A complete packet to be processed by the hook. It includes the IP header
   2. 
      aInfo - Information block associated with the packet

MFlowHook* OpenL(TPacketHead &aHead, CFlowContext *aFlow);
TInt ReadyL(TPacketHead& aHead);
TInt ApplyL(RMBufSendPacket& aPacket, RMBufSendInfo& aInfo);