Eric Lee / smarc-fsl-linux-kernel

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Commit d4b812dea4a236f729526facf97df1a9d18e191c

Authored by Eric Dumazet
Committed by David S. Miller
1 parent ece793fcfc

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>

Showing 3 changed files with 11 additions and 5 deletions Side-by-side Diff

include/linux/if_vlan.h
Diff comments   View file @ d4b812d
... ... @@ -79,9 +79,8 @@
79 79 }
80 80  
81 81 #define vlan_tx_tag_present(__skb) ((__skb)->vlan_tci & VLAN_TAG_PRESENT)
82   -#define vlan_tx_nonzero_tag_present(__skb) \
83   - (vlan_tx_tag_present(__skb) && ((__skb)->vlan_tci & VLAN_VID_MASK))
84 82 #define vlan_tx_tag_get(__skb) ((__skb)->vlan_tci & ~VLAN_TAG_PRESENT)
  83 +#define vlan_tx_tag_get_id(__skb) ((__skb)->vlan_tci & VLAN_VID_MASK)
85 84  
86 85 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
87 86  
net/8021q/vlan_core.c
Diff comments   View file @ d4b812d
... ... @@ -9,7 +9,7 @@
9 9 {
10 10 struct sk_buff *skb = *skbp;
11 11 __be16 vlan_proto = skb->vlan_proto;
12   - u16 vlan_id = skb->vlan_tci & VLAN_VID_MASK;
  12 + u16 vlan_id = vlan_tx_tag_get_id(skb);
13 13 struct net_device *vlan_dev;
14 14 struct vlan_pcpu_stats *rx_stats;
15 15  
... ... @@ -3580,8 +3580,15 @@
3580 3580 }
3581 3581 }
3582 3582  
3583   - if (vlan_tx_nonzero_tag_present(skb))
3584   - skb->pkt_type = PACKET_OTHERHOST;
  3583 + if (unlikely(vlan_tx_tag_present(skb))) {
  3584 + if (vlan_tx_tag_get_id(skb))
  3585 + skb->pkt_type = PACKET_OTHERHOST;
  3586 + /* Note: we might in the future use prio bits
  3587 + * and set skb->priority like in vlan_do_receive()
  3588 + * For the time being, just ignore Priority Code Point
  3589 + */
  3590 + skb->vlan_tci = 0;
  3591 + }
3585 3592  
3586 3593 /* deliver only exact match when indicated */
3587 3594 null_or_dev = deliver_exact ? skb->dev : NULL;