Re: [Anima-bootstrap] Anima bootstrap: discover protocol multicast notes

Michael Richardson <mcr+ietf@sandelman.ca> Sun, 12 February 2017 22:02 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Brian E Carpenter <brian.e.carpenter@gmail.com>
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References: <20170117171732.GA14606@faui40p.informatik.uni-erlangen.de> <20170117172824.GB14606@faui40p.informatik.uni-erlangen.de> <c5daca2c-2c33-ee33-3415-7ce01a49715f@gmail.com>
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Date: Sun, 12 Feb 2017 17:02:49 -0500
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Cc: anima-bootstrap@ietf.org
Subject: Re: [Anima-bootstrap] Anima bootstrap: discover protocol multicast notes
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Brian E Carpenter <brian.e.carpenter@gmail.com> wrote:
    >> This information is typically ignored in existing network protocol
    >> stacks
    >> and is also typically unavailable on the socket-API. This IMHO makes
    >> it highly beneficial to
    >> use a very lightweight protocol (like the subset of GRASP dedicate to
    >> this) that can specifically
    >> be implemented to do this security check.

    > Presumably you have to use a raw socket. I don't see any other way to get the
    > destination address out of the packet.

With recvmsg(), you can can as for IPV6_RECVPKTINFO in the auxiliary
messages in IPV6_PKTINFO.  You get the destination IPv6 address as well as
the ifindex.  (ifindex is pretty essential if you are receiving multicast messages)

--
Michael Richardson <mcr+IETF@sandelman.ca>ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-