From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH] NET: Proper handling of IPv6 header in tun driver when TUN_NO_PI is set Date: Fri, 6 Jun 2008 13:48:33 -0700 Message-ID: <20080606134833.3a5a8dc2@extreme> References: <4849162D.7000401@nav6.org> <48499C32.6070703@qualcomm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Ang Way Chuang , David Miller , "Zabele, Stephen (US SSA)" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Max Krasnyanskiy Return-path: Received: from mail.vyatta.com ([216.93.170.194]:35647 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755101AbYFFUsi (ORCPT ); Fri, 6 Jun 2008 16:48:38 -0400 In-Reply-To: <48499C32.6070703@qualcomm.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 06 Jun 2008 13:21:06 -0700 Max Krasnyanskiy wrote: > 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) { 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