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kernel/include/linux/if_vlan.h
Cong Wang da8c87241c vlan: adjust vlan_set_encap_proto() for its callers 
There are two places to call vlan_set_encap_proto():
vlan_untag() and __pop_vlan_tci().

vlan_untag() assumes skb->data points after mac addr, otherwise
the following code

        vhdr = (struct vlan_hdr *) skb->data;
        vlan_tci = ntohs(vhdr->h_vlan_TCI);
        __vlan_hwaccel_put_tag(skb, vlan_tci);

        skb_pull_rcsum(skb, VLAN_HLEN);

won't be correct. But __pop_vlan_tci() assumes points _before_
mac addr.

In vlan_set_encap_proto(), it looks for some magic L2 value
after mac addr:

        rawp = skb->data;
        if (*(unsigned short *) rawp == 0xFFFF)
	...

Therefore __pop_vlan_tci() is obviously wrong.

A quick fix is avoiding using skb->data in vlan_set_encap_proto(),
use 'vhdr+1' is always correct in both cases.

Cc: David S. Miller <davem@davemloft.net>
Cc: Jesse Gross <jesse@nicira.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-02-23 21:00:06 -05:00

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/*
* VLAN An implementation of 802.1Q VLAN tagging.
*
* Authors: Ben Greear <greearb@candelatech.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#ifndef _LINUX_IF_VLAN_H_
#define _LINUX_IF_VLAN_H_
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/bug.h>
#include <uapi/linux/if_vlan.h>
#define VLAN_HLEN 4 /* The additional bytes required by VLAN
* (in addition to the Ethernet header)
*/
#define VLAN_ETH_HLEN 18 /* Total octets in header. */
#define VLAN_ETH_ZLEN 64 /* Min. octets in frame sans FCS */
/*
* According to 802.3ac, the packet can be 4 bytes longer. --Klika Jan
*/
#define VLAN_ETH_DATA_LEN 1500 /* Max. octets in payload */
#define VLAN_ETH_FRAME_LEN 1518 /* Max. octets in frame sans FCS */
/*
* struct vlan_hdr - vlan header
* @h_vlan_TCI: priority and VLAN ID
* @h_vlan_encapsulated_proto: packet type ID or len
*/
struct vlan_hdr {
__be16 h_vlan_TCI;
__be16 h_vlan_encapsulated_proto;
};
/**
* struct vlan_ethhdr - vlan ethernet header (ethhdr + vlan_hdr)
* @h_dest: destination ethernet address
* @h_source: source ethernet address
* @h_vlan_proto: ethernet protocol (always 0x8100)
* @h_vlan_TCI: priority and VLAN ID
* @h_vlan_encapsulated_proto: packet type ID or len
*/
struct vlan_ethhdr {
unsigned char h_dest[ETH_ALEN];
unsigned char h_source[ETH_ALEN];
__be16 h_vlan_proto;
__be16 h_vlan_TCI;
__be16 h_vlan_encapsulated_proto;
};
#include <linux/skbuff.h>
static inline struct vlan_ethhdr *vlan_eth_hdr(const struct sk_buff *skb)
{
return (struct vlan_ethhdr *)skb_mac_header(skb);
}
#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 */
#define VLAN_N_VID 4096
/* found in socket.c */
extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
static inline int is_vlan_dev(struct net_device *dev)
{
return dev->priv_flags & IFF_802_1Q_VLAN;
}
#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)
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
extern struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
u16 vlan_id);
extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
extern u16 vlan_dev_vlan_id(const struct net_device *dev);
extern bool vlan_do_receive(struct sk_buff **skb);
extern struct sk_buff *vlan_untag(struct sk_buff *skb);
extern int vlan_vid_add(struct net_device *dev, unsigned short vid);
extern void vlan_vid_del(struct net_device *dev, unsigned short vid);
extern int vlan_vids_add_by_dev(struct net_device *dev,
const struct net_device *by_dev);
extern void vlan_vids_del_by_dev(struct net_device *dev,
const struct net_device *by_dev);
extern bool vlan_uses_dev(const struct net_device *dev);
#else
static inline struct net_device *
__vlan_find_dev_deep(struct net_device *real_dev, u16 vlan_id)
{
return NULL;
}
static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
{
BUG();
return NULL;
}
static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
{
BUG();
return 0;
}
static inline bool vlan_do_receive(struct sk_buff **skb)
{
return false;
}
static inline struct sk_buff *vlan_untag(struct sk_buff *skb)
{
return skb;
}
static inline int vlan_vid_add(struct net_device *dev, unsigned short vid)
{
return 0;
}
static inline void vlan_vid_del(struct net_device *dev, unsigned short vid)
{
}
static inline int vlan_vids_add_by_dev(struct net_device *dev,
const struct net_device *by_dev)
{
return 0;
}
static inline void vlan_vids_del_by_dev(struct net_device *dev,
const struct net_device *by_dev)
{
}
static inline bool vlan_uses_dev(const struct net_device *dev)
{
return false;
}
#endif
/**
* vlan_insert_tag - regular VLAN tag inserting
* @skb: skbuff to tag
* @vlan_tci: VLAN TCI to insert
*
* Inserts the VLAN tag into @skb as part of the payload
* Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
*
* Following the skb_unshare() example, in case of error, the calling function
* doesn't have to worry about freeing the original skb.
*
* Does not change skb->protocol so this function can be used during receive.
*/
static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb, u16 vlan_tci)
{
struct vlan_ethhdr *veth;
if (skb_cow_head(skb, VLAN_HLEN) < 0) {
kfree_skb(skb);
return NULL;
}
veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
/* Move the mac addresses to the beginning of the new header. */
memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);
skb->mac_header -= VLAN_HLEN;
/* first, the ethernet type */
veth->h_vlan_proto = htons(ETH_P_8021Q);
/* now, the TCI */
veth->h_vlan_TCI = htons(vlan_tci);
return skb;
}
/**
* __vlan_put_tag - regular VLAN tag inserting
* @skb: skbuff to tag
* @vlan_tci: VLAN TCI to insert
*
* Inserts the VLAN tag into @skb as part of the payload
* Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
*
* Following the skb_unshare() example, in case of error, the calling function
* doesn't have to worry about freeing the original skb.
*/
static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, u16 vlan_tci)
{
skb = vlan_insert_tag(skb, vlan_tci);
if (skb)
skb->protocol = htons(ETH_P_8021Q);
return skb;
}
/**
* __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
* @skb: skbuff to tag
* @vlan_tci: VLAN TCI to insert
*
* Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
*/
static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb,
u16 vlan_tci)
{
skb->vlan_tci = VLAN_TAG_PRESENT | vlan_tci;
return skb;
}
#define HAVE_VLAN_PUT_TAG
/**
* vlan_put_tag - inserts VLAN tag according to device features
* @skb: skbuff to tag
* @vlan_tci: VLAN TCI to insert
*
* Assumes skb->dev is the target that will xmit this frame.
* Returns a VLAN tagged skb.
*/
static inline struct sk_buff *vlan_put_tag(struct sk_buff *skb, u16 vlan_tci)
{
if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
return __vlan_hwaccel_put_tag(skb, vlan_tci);
} else {
return __vlan_put_tag(skb, vlan_tci);
}
}
/**
* __vlan_get_tag - get the VLAN ID that is part of the payload
* @skb: skbuff to query
* @vlan_tci: buffer to store vlaue
*
* Returns error if the skb is not of VLAN type
*/
static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
{
struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
if (veth->h_vlan_proto != htons(ETH_P_8021Q)) {
return -EINVAL;
}
*vlan_tci = ntohs(veth->h_vlan_TCI);
return 0;
}
/**
* __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
* @skb: skbuff to query
* @vlan_tci: buffer to store vlaue
*
* Returns error if @skb->vlan_tci is not set correctly
*/
static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
u16 *vlan_tci)
{
if (vlan_tx_tag_present(skb)) {
*vlan_tci = vlan_tx_tag_get(skb);
return 0;
} else {
*vlan_tci = 0;
return -EINVAL;
}
}
#define HAVE_VLAN_GET_TAG
/**
* vlan_get_tag - get the VLAN ID from the skb
* @skb: skbuff to query
* @vlan_tci: buffer to store vlaue
*
* Returns error if the skb is not VLAN tagged
*/
static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
{
if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
return __vlan_hwaccel_get_tag(skb, vlan_tci);
} else {
return __vlan_get_tag(skb, vlan_tci);
}
}
/**
* vlan_get_protocol - get protocol EtherType.
* @skb: skbuff to query
*
* Returns the EtherType of the packet, regardless of whether it is
* vlan encapsulated (normal or hardware accelerated) or not.
*/
static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
{
__be16 protocol = 0;
if (vlan_tx_tag_present(skb) ||
skb->protocol != cpu_to_be16(ETH_P_8021Q))
protocol = skb->protocol;
else {
__be16 proto, *protop;
protop = skb_header_pointer(skb, offsetof(struct vlan_ethhdr,
h_vlan_encapsulated_proto),
sizeof(proto), &proto);
if (likely(protop))
protocol = *protop;
}
return protocol;
}
static inline void vlan_set_encap_proto(struct sk_buff *skb,
struct vlan_hdr *vhdr)
{
__be16 proto;
unsigned short *rawp;
/*
* Was a VLAN packet, grab the encapsulated protocol, which the layer
* three protocols care about.
*/
proto = vhdr->h_vlan_encapsulated_proto;
if (ntohs(proto) >= 1536) {
skb->protocol = proto;
return;
}
rawp = (unsigned short *)(vhdr + 1);
if (*rawp == 0xFFFF)
/*
* This is a magic hack to spot IPX packets. Older Novell
* breaks the protocol design and runs IPX over 802.3 without
* an 802.2 LLC layer. We look for FFFF which isn't a used
* 802.2 SSAP/DSAP. This won't work for fault tolerant netware
* but does for the rest.
*/
skb->protocol = htons(ETH_P_802_3);
else
/*
* Real 802.2 LLC
*/
skb->protocol = htons(ETH_P_802_2);
}
#endif /* !(_LINUX_IF_VLAN_H_) */
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