[lwip-users] add ICMP Destination unreachable

[Andreas Becker]

Hi all,

I'm thinking about to extend LWIP with the processing of a 
ICMP-destination-unreachable Message.

What would be the best way to provide this to the lwip-callback-api-user?
I need the ICMP-type: "Destination unreachable" and the ICMP-Code 
"0: no net, 1: no host , 2: no port ,.., 15"
Pehaps use a LWIP_ERR and the udp/tcp_err callbacks and add a 
err_icmp_dest_unr.
But if I do so: how to pass the icmp-code to the user? ... Add five new 
errors ?? err_icmp_dest_unr_NET, err_icmp_dest_unr_HOST...??

Is an ICMP an real error? Schould I terminate the connection if I receive an 
ICMP-Dest-unreachable, or could this be a temporary error, for example if a 
router uses a dial-up connection?

The other way is to add an new callback funktion udp/tcp_icmp like _recv().
And then add a option to lwipopts.h? 

Any other ideas??





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MEng Dipl.-Ing.(FH) Andreas Becker
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