Re: [lwip-devel] Receive a UDP packet on multiple PCBs ? (same port)

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I took that mail as a starter to work on the REUSEADDR code for 1.4.0 
and digging out an explanation of this option, I found that on other 
systems (which is what we want to be like, hehe), the incoming data is 
only duplicated if it was sent to a multi- or broadcast address. So if 
you are trying to receive unicast traffic on multiple PCBs, I don't 
think that's going to work with lwIP even if REUSEADDR is fully implemented.

Simon


Stéphane Lesage wrote:
> Hi,
>
> My LwIP device can decode 2 UDP streams (mp3, speex) to 2 audio outputs.
> This is working.
> But I meet a new case where we want to decode the same stream on both
> decoder/outputs
> (2 independent amplifiers).
>
> Currently, only the last PCB (socket) receives the packets. (there's no
> bind() problem)
>
> In udp.c, this is clear:
>      /* Iterate through the UDP pcb list for a matching pcb.
>       * 'Perfect match' pcbs (connected to the remote port&  ip address) are
>       * preferred. If no perfect match is found, the first unconnected
> pcb that
>       * matches the local port and ip address gets the datagram. */
>
> I don't know how an IP stack is supposed to behave in this case...
> Is it possible to change that and copy+send the datagram to all
> matchings PCBs ?
>
>