From 05423b241311c9380b7280179295bac7794281b6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 26 Oct 2009 18:40:35 -0700 Subject: vlan: allow null VLAN ID to be used We currently use a 16 bit field (vlan_tci) to store VLAN ID/PRIO on a skb. Null value is used as a special value, meaning vlan tagging not enabled. This forbids use of null vlan ID. As pointed by David, some drivers use the 3 high order bits (PRIO) As VLAN ID is 12 bits, we can use the remaining bit (CFI) as a flag, and allow null VLAN ID. In case future code really wants to use VLAN_CFI_MASK, we'll have to use a bit outside of vlan_tci. #define VLAN_PRIO_MASK 0xe000 /* Priority Code Point */ #define VLAN_PRIO_SHIFT 13 #define VLAN_CFI_MASK 0x1000 /* Canonical Format Indicator */ #define VLAN_TAG_PRESENT VLAN_CFI_MASK #define VLAN_VID_MASK 0x0fff /* VLAN Identifier */ Reported-by: Gertjan Hofman Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/8021q/vlan_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/8021q/vlan_dev.c') diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index 4198ec5c8abc..e3701977f58d 100644 --- a/net/8021q/vlan_dev.c +++ b/net/8021q/vlan_dev.c @@ -393,7 +393,7 @@ int vlan_dev_set_egress_priority(const struct net_device *dev, struct vlan_dev_info *vlan = vlan_dev_info(dev); struct vlan_priority_tci_mapping *mp = NULL; struct vlan_priority_tci_mapping *np; - u32 vlan_qos = (vlan_prio << 13) & 0xE000; + u32 vlan_qos = (vlan_prio << VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK; /* See if a priority mapping exists.. */ mp = vlan->egress_priority_map[skb_prio & 0xF]; -- cgit v1.2.3