From d4b812dea4a236f729526facf97df1a9d18e191c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 18 Jul 2013 07:19:26 -0700 Subject: [PATCH] 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 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- 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 cdcbafa9b39a..715c343f7c00 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 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; -- 2.20.1