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authorEric Dumazet <edumazet@google.com>2013-07-18 07:19:26 -0700
committerDavid S. Miller <davem@davemloft.net>2013-07-18 13:05:23 -0700
commitd4b812dea4a236f729526facf97df1a9d18e191c (patch)
tree55effa330847edd70cf20502603c23e4ca8084a4 /net
parentece793fcfc417b3925844be88a6a6dc82ae8f7c6 (diff)
downloadlinux-d4b812dea4a236f729526facf97df1a9d18e191c.tar.gz
vlan: mask vlan prio bits
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@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/8021q/vlan_core.c2
-rw-r--r--net/core/dev.c11
2 files changed, 10 insertions, 3 deletions
diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index 8a15eaadc4bd..4a78c4de9f20 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 a3d8d44cb7f4..26755dd40daa 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;