[haiku-gsoc] Re: [HCD] ICMP errors handling & propagation project

<philippe.houdoin@xxxxxxx> wrote:
> Last year, IIRC, Hugo Santos, a GSoC 2007 student, introduced two new 
> hooks
> to net_protocol API: error() and error_reply().

Actually that was me -- and I mostly copied it from the BONE headers 
without giving it too much thought :-)

> My understanding on the way these hooks should be used is that one:
> - The error() hook is supposed to be called when an error is 
> propagated toward
> *upper* protocols, like on host unreachable ICMP message reception, 
> which should
> be propagate up to UDP, TCP.
> - The error_reply() hook is supposed to be called by a protocol to 
> propagated to *lower*
> protocols an error, like... source quench notification from TCP ?

Exactly. We could rename error() to error_received() to make this a bit 
clearer. 

> A good starting point would be code in trunk/src/add-ons/kernel/
> network/protocols/icmp/,
> to see what level of ICMP feature is already there (minimal only).

Currently, it's mostly the echo feature.
Also of interest would be the following discussion:
http://www.freelists.org/archives/haiku-development/03-2008/msg00462.html

This was the initial proposal by Alan Alvarez who we lost to KDE.
Also of interest might be the basic overview over the network stack:
http://www.haiku-os.org/documents/dev/haiku_network_stack_architecture

Bye,
   Axel.

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