From mboxrd@z Thu Jan 1 00:00:00 1970 From: Max Krasnyanskiy Subject: Re: [PATCH] NET: Proper handling of IPv6 header in tun driver when TUN_NO_PI is set Date: Fri, 06 Jun 2008 13:21:06 -0700 Message-ID: <48499C32.6070703@qualcomm.com> References: <4849162D.7000401@nav6.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Ang Way Chuang , David Miller , "Zabele, Stephen (US SSA)" Return-path: In-Reply-To: <4849162D.7000401@nav6.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Acked-by: Max Krasnyansky 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 > --- > > 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) { > + case 0x40: > + pi.proto = __constant_htons(ETH_P_IP); > + 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; > > -- >