From: Florian Westphal <fw@strlen•de>
To: David Miller <davem@davemloft•net>
Cc: fw@strlen•de, netdev@vger•kernel.org
Subject: Re: [PATCH] macvlan: fix oops with vlan-on-top and HW_VLAN_CTAG_TX lowerdev
Date: Mon, 30 Dec 2013 11:27:12 +0100 [thread overview]
Message-ID: <20131230102712.GO29632@breakpoint.cc> (raw)
In-Reply-To: <20131229.170121.154913581019152817.davem@davemloft.net>
David Miller <davem@davemloft•net> wrote:
> From: Florian Westphal <fw@strlen•de>
> Date: Sat, 28 Dec 2013 14:38:40 +0100
>
> > Or is the real bug the use of netdev_priv in macvlan_hard_header()?
>
> That's a really good question.
[..]
> So the more I think about this, the more I think that the operations
> assignment VLAN is doing is illegal. If it wants to "pass through"
> it must do so with explicit handlers, ones that pass the expected
> device to the hard header ops.
Both bonding and team seem to do the same. Guess it was never
a problem since most create hooks don't use netdev_priv.
> So vlan_dev.c would have things like:
>
> static int vlan_passthru_hard_header(struct sk_buff *skb, struct net_device *dev,
> unsigned short type,
> const void *daddr, const void *saddr,
> unsigned int len)
> {
> struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
> struct net_device *real_dev = vlan->real_dev;
>
> return real_dev->header_ops->create(skb, real_dev, type, daddr, saddr, len);
> }
I wonder if this needs to use dev_hard_header() to protect against
NULL header_ops/create hook. macvlan does this.
> static int vlan_passthru_rebuild_header(struct sk_buff *skb)
> {
> struct net_device *dev = skb->dev;
> struct net_device *real_dev;
> struct vlan_dev_priv *vlan;
>
> vlan = vlan_dev_priv(dev);
> real_dev = vlan->real_dev;
>
> return real_dev->header_ops->rebuild(skb);
> }
similar, e.g. drivers/net/plip/plip.c defines 'create' and 'cache' but
no 'rebuild'.
> Can someone test this?
Here is what i did in qemu guest running net-tree+your patch below:
ip link add link eth0 name wan0 type macvlan
ip link add link wan0 name wan1 type vlan id 2
ip link set wan0 up
[ without your patch it would oops real soon now ]
ip addr add 10.0.0.2/8 dev wan1
ip link set wan1 up
- host/guest can xmit data using vlan interface (tested with netcat)
- tcpdump -ne on host shows:
[ .. ] 9:fc:b7, ethertype 802.1Q (0x8100), length 1518: vlan 2, p 0, ethertype IPv4, 10.0.0.1.12345 > 10.0.0.2.50369 [..]
ethtool -k wan0 on guest shows:
rx-vlan-offload: on [fixed]
tx-vlan-offload: on [fixed]
So, this looks good to me.
Many thanks for investigating this issue!
next prev parent reply other threads:[~2013-12-30 10:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-28 13:38 [PATCH] macvlan: fix oops with vlan-on-top and HW_VLAN_CTAG_TX lowerdev Florian Westphal
2013-12-29 22:01 ` David Miller
2013-12-30 10:27 ` Florian Westphal [this message]
2013-12-31 21:24 ` David Miller
2014-01-03 11:39 ` Florian Westphal
2014-01-03 20:33 ` David Miller
2014-01-04 13:51 ` Florian Westphal
2014-01-05 1:13 ` David Miller
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