[lwip-users] RE: Multicast destination address in UDP callback?

[Joe Dupre]

> I have set up a UDP PCB where I listen to several multicast groups.
> In my UDP callback I'd like to know which multicast group the packet
> was sent to.
> How do I determine this?


OK, I see that I can use pbuf_header() to go backwards in the pbuf to look at 
the ip header.

1.  Are the lower level headers guaranteed to be there until the pbuf is freed?
2.  Is there a "better" way to do this?

- Joe