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

From: Oliver Hartkopp <[email-masked]>
Date: Tue, 02 Oct 2007 16:42:24 +0200

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 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.

Oliver