Re: Extra DLT types required for opensolaris DLPI DL

[Guy Harris <guy () alum mit edu>]

On Mar 27, 2009, at 10:58 AM, Darren Reed wrote:

> Seriously, for my purposes, it is "Cisco HDLC".

So it should be mapped to DLT_C_HDLC.

> For the purposes of my table, I'd like to map the mediums that have  
> passed (or are passing) from active use to "unsupported" and call it  
> DLT_UNSUP (0xffffffff). On one level this is strange, because it  
> isn't a DLT type, but it is a useful programming tool.

So what's the table being used for?  libpcap has a switch statement  
(in the top of the tree, it's in pcap_process_mactype() in  
dlpisubs.c), as it needs to know more than just the DLT_ value for  
particular link-layer types (and it maps DL_TPR to DLT_IEEE802).

> > > From NetBSD:
> > > #define DLT_HIPPI    15    /* HIPPI */
> >
> > From a quick look at sys/net/if_hippi.h and sys/net/if_hippisubr.c,  
> > the header appears to be:
> > ...
> > If there are interfaces using DL_HIPPI, and they supply the same  
> > link-layer header, a DLT_HIPPI would make sense.  Unfortunately, 15  
> > is in the Badlands of DLT_ values, where various OSes have used the  
> > same numerical value for different purposes, so we'd probably end  
> > up assigning a new value in the range starting with 100 (which is  
> > the range we're maintaining).
>
> If you can give it a new number, I can see to it that the change  
> gets into NetBSD. I can't see a whole lot of people screaming if it  
> does change ;)

So is the header what I described it as?

While you're at it, you might change the drivers in NetBSD that use  
DLT_HDLC for Cisco HDLC (such as sys/dev/ic/hd64570.c) to use  
DLT_C_HDLC, as NetBSD's sys/net/dlt.h already defines DLT_C_HDLC with  
the correct value.

> Additionally, I'm considering creating a new datalink type for  
> loopback packets on OpenSolaris. The contents would be something like:
> version (16 bits: 1)
> protocol family (16 bits: AF_INET, AF_INET6)
> capture point (32bits enum: local, in, out)
> interface index (32bits)
> group interface index (32bits)
> source zone (32 or 64bits?)
> destination zone (32 or 64bits?)
> I'm guessing that this should be called DLT_LOOP_SOLARIS.

That would probably be the right name.  Shall I assign it (once you've  
decided how big the source and destination zones are, or whether there  
are two flavors, one with 32 bits and one with 64 bits)?
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