Re: Patch to implement SIOCGIFINDEX

[Dennis Ferguson <dennis.c.ferguson%gmail.com@localhost>]

On 2 Apr, 2013, at 17:32 , Alan Barrett <apb%cequrux.com@localhost> wrote:
> On Mon, 01 Apr 2013, Ty Sarna wrote:
>> The following short patch implements SIOCGIFINDEX as found on Linux
>> (and maybe elsewhere), which translates an interface name to its index.
> 
> Why is that useful?  Once one know the index, what can or should one
> do with it?

It is used in recvmsg() control messages to indicate the incoming interface a
packet arrived on.  It is also used to indicate the interface a multicast
you are sending (maybe a 255.255.255.255 broadcast, also) should be sent out
of.

Dennis Ferguson