Re: [lwip-users] LWIP and second IP feasible?

[Kelly_C]

Simon Goldschmidt wrote:
> 
> Kelly_C <address@hidden> wrote:
> 
>> Can you provide a sample of the code you wrote to determine which netif
>> to
>> pass the input function to?
> 
> Let me see what I can find when I'm back in the office on Monday :-)
> 
> Simon
>> 
> 
> 

Thank Simon!  I really appreciate any examples/assistance you can provide. 
I am brand new to lwIP, so trying to ramp up quickly and then do something
unsual like this doesn't help...

For some background, I would like to enable 4 or 5 (or x) IP addresses on
the same interface.  It is to satisfy legacy requirements with a system I am
interfacing with.  I am working with AVR32 platform, using FreeRTOS and lwIP
1.3.2.

I am curious if your implementation requires multiple threads to handle
ethernetif_input for each interface.  It doesn't seem that it would be
required, but I have tried both ways with problems in either case.  When
allowing a thread for each interface, I am observing problems with ARP
resolution as the source TCP/IP packet gets sent, but depending on which
interface thread picks up the packet, it will simply refuse to respond
because it doesn't match the IP of that interface associated that specific
thread.  The function etharp_arp_input does not check the list of
interfaces, only the one passed to it.

I also note that my MAC supports up to 4 unique hw addresses.  Should this
be utilized or is it completely unnecessary?  I had thought if I only had 4
IP addresses, associating them each with a different hw address would
provide an easy way to filter the incoming data and pass the corresponding
interface to the input function.  But this doesn't solve the ARP problem, as
there is still an exchange that must occur for the source to determine which
hw addr will respond to the dest IP address.

I have seen comments related to lwIP 1.4.0 possibly including support for
multiple IP addresses.  Is this a feature I can look forward too?

-Kelly
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