Commit 05423b24 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarGertjan Hofman <gertjan_hofman@yahoo.com>
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9dbb58d8

include/linux/if_vlan.h

+9 −5
Original line number Diff line number Diff line
@@ -63,7 +63,11 @@ static inline struct vlan_ethhdr *vlan_eth_hdr(const struct sk_buff *skb) 
	return (struct vlan_ethhdr *)skb_mac_header(skb);

}



#define VLAN_VID_MASK	0xfff

#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 */



/* found in socket.c */

extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
@@ -105,8 +109,8 @@ static inline void vlan_group_set_device(struct vlan_group *vg, 
	array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] = dev;

}



#define vlan_tx_tag_present(__skb)	((__skb)->vlan_tci)

#define vlan_tx_tag_get(__skb)		((__skb)->vlan_tci)

#define vlan_tx_tag_present(__skb)	((__skb)->vlan_tci & VLAN_TAG_PRESENT)

#define vlan_tx_tag_get(__skb)		((__skb)->vlan_tci & ~VLAN_TAG_PRESENT)



#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)

extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
@@ -231,7 +235,7 @@ static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, u16 vlan_tci) 
static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb,

						     u16 vlan_tci)

{

	skb->vlan_tci = vlan_tci;

	skb->vlan_tci = VLAN_TAG_PRESENT | vlan_tci;

	return skb;

}
@@ -284,7 +288,7 @@ static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb, 
					 u16 *vlan_tci)

{

	if (vlan_tx_tag_present(skb)) {

		*vlan_tci = skb->vlan_tci;

		*vlan_tci = vlan_tx_tag_get(skb);

		return 0;

	} else {

		*vlan_tci = 0;

net/8021q/vlan.h

+1 −1
Original line number Diff line number Diff line
@@ -89,7 +89,7 @@ static inline u32 vlan_get_ingress_priority(struct net_device *dev, 
{

	struct vlan_dev_info *vip = vlan_dev_info(dev);



	return vip->ingress_priority_map[(vlan_tci >> 13) & 0x7];

	return vip->ingress_priority_map[(vlan_tci >> VLAN_PRIO_SHIFT) & 0x7];

}



#ifdef CONFIG_VLAN_8021Q_GVRP

net/8021q/vlan_dev.c

+1 −1
Original line number Diff line number Diff line
@@ -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];

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -2300,7 +2300,7 @@ int netif_receive_skb(struct sk_buff *skb) 
	if (!skb->tstamp.tv64)

		net_timestamp(skb);



	if (skb->vlan_tci && vlan_hwaccel_do_receive(skb))

	if (vlan_tx_tag_present(skb) && vlan_hwaccel_do_receive(skb))

		return NET_RX_SUCCESS;



	/* if we've gotten here through NAPI, check netpoll */

net/packet/af_packet.c

+3 −2
Original line number Diff line number Diff line
@@ -79,6 +79,7 @@ 
#include <linux/module.h>

#include <linux/init.h>

#include <linux/mutex.h>

#include <linux/if_vlan.h>



#ifdef CONFIG_INET

#include <net/inet_common.h>
@@ -766,7 +767,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, 
			getnstimeofday(&ts);

		h.h2->tp_sec = ts.tv_sec;

		h.h2->tp_nsec = ts.tv_nsec;

		h.h2->tp_vlan_tci = skb->vlan_tci;

		h.h2->tp_vlan_tci = vlan_tx_tag_get(skb);

		hdrlen = sizeof(*h.h2);

		break;

	default:
@@ -1493,7 +1494,7 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, 
		aux.tp_snaplen = skb->len;

		aux.tp_mac = 0;

		aux.tp_net = skb_network_offset(skb);

		aux.tp_vlan_tci = skb->vlan_tci;

		aux.tp_vlan_tci = vlan_tx_tag_get(skb);



		put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);

	}

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