Re: RFC: Add multicast reception API to libpcap

["Bruce M. Simpson" <bms () icir org>]

Rick Jones wrote:
> So this is meant to enable receipt of specific multicasts and not 
> receipt of all multicasts right?  Is that a particularly "pcappy" thing?

Correct. I believe it logically belongs with pcap, as it is something 
which may well be required if using pcap as the link-layer API.

> Anyway, for HP-UX and Solaris, I suspect the receive all multicasts 
> would be a DL_PROMISC_MULTI rather than the (i suspect) current 
> DL_PROMISC_PHYS

I must admit I didn't consider the all-multicasts case for this 
proposal; this is because that functionality is largely under kernel 
control, at least for BSD and Linux derived systems.

Generally all-multicast is only enabled if the kernel detects that 
multicast forwarding is enabled on the interface. There are a number of 
wireless cards out there which don't support it, notably the Prism2.

I suppose in the absence of a specific multicast filter list it is 
reasonable to request all-multicast if the OS and driver support that as 
an alternative.

kind regards,
BMS
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