[support] Acquire and Report Messages

[Arnaud Ebalard]

Hi,

"Thiago Bemerguy" <thiagobemerguy at gmail.com> writes:

> What's the meaning of receiving a xfrm ACQUIRE message and a REPORT message?
>
>  
>
> I was reading the mipv6 source and found some code I couldn't understand:
>
>                 When a listener thread receives an ACQUIRE it starts RO.
>
>                 And when it receives a REPORT it sends a BE.
>
>  
>
> Could you please help me understand this thing?

UMIP installs some specific optional XFRM policies (with no state) with
selectors matching traffic to a given peer to be warned by the kernel
when such traffic is exchanged. The way UMIP is informed is via a XFRM
ACQUIRE message (this is the same kind of message used by the kernel
when warning an IKE daemon that it needs a SA for some traffic matching
a given SP). 

I would have to check the code for the REPORT but I think this is the
same idea (being warned by the kernel that some specific traffic was
received).

Hope that helps,

Cheers,

a+