* [RFC] vlan: mask vlan prio bits
@ 2013-07-17 17:44 Eric Dumazet
2013-07-18 0:58 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Eric Dumazet @ 2013-07-17 17:44 UTC (permalink / raw)
To: David Miller; +Cc: netdev, Florian Zumbiehl, Steinar H. Gunderson
In commit 48cc32d38a52d0b68f91a171a8d00531edc6a46e
("vlan: don't deliver frames for unknown vlans to protocols")
Florian made sure we set PACKET_OTHERHOST if the vlan id is set
and we could find a vlan device for this particular id.
But we also have a problem if prio bits are set.
Steinar has an issue on a router receiving IPv6 frames with a vlan tag
of 4000 (prio = 2), and tunneled into a sit device, because
skb->vlan_tci is set :
We insert a VLAN tag in forwarded frame after sit tunnel.
Frame is completely corrupted : We can see (8100:4000) being inserted in
the middle of IPv6 source address :
16:48:00.780413 IP6 2001:16d8:8100:4000:ee1c:0:9d9:bc87 >
9f94:4d95:2001:67c:29f4::: ICMP6, unknown icmp6 type (0), length 64
0x0000: 0000 0029 8000 c7c3 7103 0001 a0ae e651
0x0010: 0000 0000 ccce 0b00 0000 0000 1011 1213
0x0020: 1415 1617 1819 1a1b 1c1d 1e1f 2021 2223
0x0030: 2425 2627 2829 2a2b 2c2d 2e2f 3031 3233
It seems we are not really ready to properly cope with this right now.
Should we clear skb->vlan_tci in iptunnel_xmit(), or should we clear it
in __netif_receive_skb_core() like in this patch ?
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index cdcbafa..715c343 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -79,9 +79,8 @@ static inline int is_vlan_dev(struct net_device *dev)
}
#define vlan_tx_tag_present(__skb) ((__skb)->vlan_tci & VLAN_TAG_PRESENT)
-#define vlan_tx_nonzero_tag_present(__skb) \
- (vlan_tx_tag_present(__skb) && ((__skb)->vlan_tci & VLAN_VID_MASK))
#define vlan_tx_tag_get(__skb) ((__skb)->vlan_tci & ~VLAN_TAG_PRESENT)
+#define vlan_tx_tag_get_id(__skb) ((__skb)->vlan_tci & VLAN_VID_MASK)
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index 8a15eaa..4a78c4d 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -9,7 +9,7 @@ bool vlan_do_receive(struct sk_buff **skbp)
{
struct sk_buff *skb = *skbp;
__be16 vlan_proto = skb->vlan_proto;
- u16 vlan_id = skb->vlan_tci & VLAN_VID_MASK;
+ u16 vlan_id = vlan_tx_tag_get_id(skb);
struct net_device *vlan_dev;
struct vlan_pcpu_stats *rx_stats;
diff --git a/net/core/dev.c b/net/core/dev.c
index a3d8d44..133b75a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3580,8 +3580,11 @@ ncls:
}
}
- if (vlan_tx_nonzero_tag_present(skb))
- skb->pkt_type = PACKET_OTHERHOST;
+ if (vlan_tx_tag_present(skb)) {
+ if (vlan_tx_tag_get_id(skb))
+ skb->pkt_type = PACKET_OTHERHOST;
+ skb->vlan_tci = 0;
+ }
/* deliver only exact match when indicated */
null_or_dev = deliver_exact ? skb->dev : NULL;
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [RFC] vlan: mask vlan prio bits
2013-07-17 17:44 [RFC] vlan: mask vlan prio bits Eric Dumazet
@ 2013-07-18 0:58 ` David Miller
2013-07-18 1:08 ` Eric Dumazet
0 siblings, 1 reply; 3+ messages in thread
From: David Miller @ 2013-07-18 0:58 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev, florz, sesse
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 17 Jul 2013 10:44:34 -0700
> Should we clear skb->vlan_tci in iptunnel_xmit(), or should we clear it
> in __netif_receive_skb_core() like in this patch ?
The safest thing to do is as early as possible, so yes your patch here
doing it in __netif_receive_skb_core() looks good to me.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC] vlan: mask vlan prio bits
2013-07-18 0:58 ` David Miller
@ 2013-07-18 1:08 ` Eric Dumazet
0 siblings, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2013-07-18 1:08 UTC (permalink / raw)
To: David Miller; +Cc: netdev, florz, sesse
On Wed, 2013-07-17 at 17:58 -0700, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Wed, 17 Jul 2013 10:44:34 -0700
>
> > Should we clear skb->vlan_tci in iptunnel_xmit(), or should we clear it
> > in __netif_receive_skb_core() like in this patch ?
>
> The safest thing to do is as early as possible, so yes your patch here
> doing it in __netif_receive_skb_core() looks good to me.
OK then, I'll send an official patch ;)
Thanks !
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-07-17 17:44 [RFC] vlan: mask vlan prio bits Eric Dumazet
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