Subject: Re: [PATCH 1/7] CAN: Allocate protocol numbers for PF_CAN

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Tue, 2 Oct 2007 11:51:39 -0300

Em Tue, Oct 02, 2007 at 04:42:24PM +0200, Oliver Hartkopp escreveu:
> Arnaldo Carvalho de Melo wrote:
>> Em Tue, Oct 02, 2007 at 03:10:07PM +0200, Urs Thuermann escreveu:
>>   
>>>
>>> Index: net-2.6.24/include/linux/if_arp.h
>>> ===================================================================
>>> --- net-2.6.24.orig/include/linux/if_arp.h	2007-10-02 12:10:51.000000000 
>>> +0200
>>> +++ net-2.6.24/include/linux/if_arp.h	2007-10-02 12:11:01.000000000 +0200
>>> @@ -52,6 +52,7 @@
>>>  #define ARPHRD_ROSE	270
>>>  #define ARPHRD_X25	271		/* CCITT X.25			*/
>>>  #define ARPHRD_HWX25	272		/* Boards with X.25 in firmware	*/
>>> +#define ARPHRD_CAN	280		/* Controller Area Network      */
>>>     
>>
>> Is 280 used in other OS? Just curious as why not using 273
>>
>>   
>
> All these definitions (PF_*, AF_*, ARPHRD_* ) are operation system specific 
> (that's why you find it in /usr/include/linux/*.h :)

I understand that, but couldn't find other reason for it not to be the
next in line (273), so thought that one could think it would be nice to
have the same number accross OSes :) But you have provided one, too much
changes in this area (TIPC, PF_CAN, etc) happening and causing clashes.

> I just googled for AF_INET and found that e.g.
> AF_APPLETALK is "16" in winsock.h and "5" in include/linux/socket.h
>
> The reason to use 280 instead of 273 was, that all the 27x stuff was 
> dedicated to the X.25 domain. So to start with a new 280 looked reasonable 
> to me.
>
> At the end of the ARPHRD_* definitions there's currently many 'change 
> traffic' due to IEEE80211.

OK.

- Arnaldo