[ntp:hackers] Broadcast/autokey

David L. Mills mills at udel.edu
Tue Feb 22 08:40:44 PST 2005


For clarity, note the following. When a broadcast or multicast packet is 
received, the association is mobilized with the unicast addresses. 
However, the addresses used for the session key are those at the 
originator, not matter what mode. Thus, a broadcast mode packet 
(broadcast or multicast) expects the broadast/multicast destination 
address, while the others expect the unicast destination address. The 
rule is that the addresses used by the sender must be the same addresses 
used by the receiver.

The original code rewrote the buffer destination address on the way in, 
so the fast_xmit routine didn't have to search for the interface. That 
was in the interest of speed. The only case in which a fast_xmit is 
called with the broadcast destination address is for the manycast server.


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