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From: Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>
To: Oliver Hartkopp <oliver-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
Cc: SocketCAN Core Mailing List
	<socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org>,
	Linux Netdev List
	<netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
Subject: Re: [PATCH net-2.6] can: Fix data length code handling in rx path
Date: Sat, 12 Dec 2009 19:09:54 +0100	[thread overview]
Message-ID: <4B23DC72.6030307@grandegger.com> (raw)
In-Reply-To: <4B23A501.9000208-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>

Oliver Hartkopp wrote:
> A valid CAN dataframe can have a data length code (DLC) of 0 .. 8 data bytes.
> 
> When reading the CAN controllers register the 4-bit value may contain values
> from 0 .. 15 which may exceed the reserved space in the socket buffer!
> 
> The ISO 11898-1 Chapter 8.4.2.3 (DLC field) says that register values > 8
> should be reduced to 8 without any error reporting or frame drop.
> 
> This patch introduces a new helper macro to cast a given 4-bit data length
> code (dlc) to __u8 and ensure the DLC value to be max. 8 bytes.
> 
> The different handlings in the rx path of the CAN netdevice drivers are fixed.
> 
> Signed-off-by: Oliver Hartkopp <oliver-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>

Signed-off-by: Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>

Thanks,

Wolfgang.

  parent reply	other threads:[~2009-12-12 18:09 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-12 14:13 [PATCH net-2.6] can: Fix data length code handling in rx path Oliver Hartkopp
     [not found] ` <4B23A501.9000208-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
2009-12-12 16:34   ` Wolfgang Grandegger
2009-12-12 17:37     ` Oliver Hartkopp
2009-12-12 18:06       ` Wolfgang Grandegger
2009-12-12 18:58         ` Oliver Hartkopp
2009-12-12 18:09   ` Wolfgang Grandegger [this message]
2009-12-14  3:47     ` David Miller

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