lkml.org 
[lkml]   [2008]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] NET: Proper handling of IPv6 header in tun driver when TUN_NO_PI is set
On Fri, 06 Jun 2008 13:21:06 -0700
Max Krasnyanskiy <maxk@qualcomm.com> wrote:

> Acked-by: Max Krasnyansky <maxk@qualcomm.com>
>
> Dave, can you please add this patch to your tree.
>
> --
> Steve, this is what I meant by "we do not need extra copy_from_user". We
> already do copy into the SKB and can parse the header right there.
>
> Max
>
>
>
>
> Ang Way Chuang wrote:
> > By default, tun.c running in TUN_TUN_DEV mode will set the protocol of
> > packet to IPv4 if TUN_NO_PI is set. My program failed to work when I
> > assumed that the driver will check the first nibble of packet, determine
> > IP version and set the appropriate protocol.
> >
> > The test for this change was conducted on 2.6.24.7 kernel. But the diff
> > is produced using git commit
> > c3b25b32e8bef526cca748e1ba023c6bdd705a99. I couldn't test it on kernel
> > version greater than 2.6.25 due to out of tree driver failing to
> > compile. But tun_get_user doesn't change that much between 2.6.24 and
> > 2.6.26, so it should work, I hope :-D. This patch is trivial because
> > this problem can also be fixed by not using TUN_NO_PI.
> >
> > Signed-off-by: Ang Way Chuang <wcang@nav6.org>
> > ---
> >
> > diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> > index 0ce07a3..77964bc 100644
> > --- a/drivers/net/tun.c
> > +++ b/drivers/net/tun.c
> > @@ -313,6 +313,21 @@ static __inline__ ssize_t tun_get_user(struct
> > tun_struct *tun, struct iovec *iv,
> >
> > switch (tun->flags & TUN_TYPE_MASK) {
> > case TUN_TUN_DEV:
> > + if (tun->flags & TUN_NO_PI) {
> > + switch (skb->data[0] & 0xf0) {

Why the magic constants, instead of proper casts and defines.
> > + case 0x40:
> > + pi.proto = __constant_htons(ETH_P_IP);

Use htons() instead of __constant_htons() it is easier to read,
and the compiler already does the right thing.

> > + break;
> > + case 0x60:
> > + pi.proto = __constant_htons(ETH_P_IPV6);
> > + break;
> > + default:
> > + tun->dev->stats.rx_dropped++;
> > + kfree_skb(skb);
> > + return -EINVAL;
> > + }
> > + }
> > +
> > skb_reset_mac_header(skb);
> > skb->protocol = pi.proto;
> > skb->dev = tun->dev;
> >
> > --
> >
>
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html


\
 
 \ /
  Last update: 2008-06-06 22:51    [from the cache]
©2003-2011 Jasper Spaans