Re: Patch to add DLT_AX25 handling to libpcap

[Richard Stearn <richard () rns-stearn demon co uk>]

Guy Harris wrote:
> Richard Stearn wrote:
>
> > What the implementors of AX.25 on Linux have done is to hand an KISS
> > packet rather than a pure AX.25 packet to the protocol stack.  This
> > probably was to accomodate the existing base of hardware where packets
> > were delivered to the system via an async serial port and the length of
> > the data is prepended.
>
>
> OK, so perhaps a new DLT_AX25_KISS should be added, to make it clear 
> that this isn't just pure AX.25.  (Among other things, some other 
> implementations might happen to provide pure AX.25 headers at some point.)
>
> Is KISS a standard independent of Linux?

Yes, KISS is independant of Linux, it originates in the hardware Terminal
Node Controller AX.25 implementations see http://www.ax25.net/kiss.htm

Adding DLT_AX25_KISS is the obvious way to go with the exception that Linux
identifies AX.25 in KISS packets as DLT_AX25 (protocol 3).

The only viable alternative I see is to check for the platform, if Linux
then apply the offset and mark the packet as DLT_AX25_KISS otherwise assume
pure AX.25.  Not sure if this is practical in libpcap.

p.s. I see you have found the KISS link.
--
Regards
        Richard
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