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Clans & chiefs mechanism is supported by a feature called deceiving:
- If ``deceit'' bit is set by sender,
L4 will lie to the receiver about the sender, delivering the
sender-specified virtual sender ID
- The receiver is alerted to the deceit by the deceit bit in
the return status
- Deceiving only works if direction preserving, i.e., if the
real sender is along the redirection chain from the virtual sender to
the receiver:
- message goes out of clan and virtual sender ID is within clan (or
subclan), or
- message goes to subclan and virtual sender ID is outside clan.
- Used by chief to make inter-clan IPC interception transparent to clients
Gernot Heiser
2002-08-07
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