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Re: [Captive-portals] Signals from the network and ICMP



On Thu, 17 May 2018 at 08:17, Michael Richardson <[email protected]>
wrote:


> Erik Kline <[email protected]> wrote:
>      > In the latter case especially, what becomes clear is that the UE
needs
>      > to be able to receive an unsolicited packet.  ICMP is a canonical
>      > example of receiving and processing an unsolicited packet.  But it
>      > could also be something like a UDP socket listening on a well known
>      > port that receives a 1-byte datagram, which causes the UE to enqueue
>      > (for rate-limiting purposes) a captive API query.

> On POSIX systems, it's clearly a lot easier to open a UDP socket from an
> unpriviledged application than to open an ICMP socket.

> Is this a consideration for you?

>      >     [3] NetworkMonitor already rate limits requests from
applications
>      > to revalidate the network, and these would likely be no different
(or
>      > pretty much the same).

> Or would NetworkMonitor do this anyway, and it has all the priviledges it
> needs anyway?

The fewer privilege escalation points the better, I suppose.  From that
perspective a UDP socket may be less concerning, but perhaps not by much.
NetworkMonitor has the appropriate privileges to do the needful, regardless.

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