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Date: Thu, 18 Jul 2013 07:19:26 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: "Steinar H. Gunderson" <sesse@...gle.com>,
Florian Zumbiehl <florz@...rz.de>,
netdev <netdev@...r.kernel.org>
Subject: [PATCH] vlan: mask vlan prio bits
From: Eric Dumazet <edumazet@...gle.com>
In commit 48cc32d38a52d0b68f91a171a8d00531edc6a46e
("vlan: don't deliver frames for unknown vlans to protocols")
Florian made sure we set pkt_type to 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 reported an issue on a router receiving IPv6 frames with a
vlan tag of 4000 (id 0, prio 2), and tunneled into a sit device,
because skb->vlan_tci is set.
Forwarded 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.
We can probably do better in future kernels :
vlan_get_ingress_priority() should be a netdev property instead of
a per vlan_dev one.
For stable kernels, lets clear vlan_tci to fix the bugs.
Reported-by: Steinar H. Gunderson <sesse@...gle.com>
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
include/linux/if_vlan.h | 3 +--
net/8021q/vlan_core.c | 2 +-
net/core/dev.c | 11 +++++++++--
3 files changed, 11 insertions(+), 5 deletions(-)
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..26755dd 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3580,8 +3580,15 @@ ncls:
}
}
- if (vlan_tx_nonzero_tag_present(skb))
- skb->pkt_type = PACKET_OTHERHOST;
+ if (unlikely(vlan_tx_tag_present(skb))) {
+ if (vlan_tx_tag_get_id(skb))
+ skb->pkt_type = PACKET_OTHERHOST;
+ /* Note: we might in the future use prio bits
+ * and set skb->priority like in vlan_do_receive()
+ * For the time being, just ignore Priority Code Point
+ */
+ skb->vlan_tci = 0;
+ }
/* deliver only exact match when indicated */
null_or_dev = deliver_exact ? skb->dev : NULL;
--
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