/*
 * 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_

#ifdef __KERNEL__

/* externally defined structs */
struct hlist_node;

#include <linux/netdevice.h>
#include <linux/etherdevice.h>

#define VLAN_HLEN       4               /* The additional bytes (on top of the Ethernet header)
                                         * that VLAN requires.
                                         */
#define VLAN_ETH_ALEN   6               /* Octets in one ethernet addr   */
#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_VID_MASK   0xfff

/* found in socket.c */
extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));

/* if this changes, algorithm will have to be reworked because this
 * depends on completely exhausting the VLAN identifier space.  Thus
 * it gives constant time look-up, but in many cases it wastes memory.
 */
#define VLAN_GROUP_ARRAY_LEN          4096
#define VLAN_GROUP_ARRAY_SPLIT_PARTS  8
#define VLAN_GROUP_ARRAY_PART_LEN     (VLAN_GROUP_ARRAY_LEN/VLAN_GROUP_ARRAY_SPLIT_PARTS)

struct vlan_group {
        struct net_device       *real_dev; /* The ethernet(like) device
                                            * the vlan is attached to.
                                            */
        unsigned int            nr_vlans;
        struct hlist_node       hlist;  /* linked list */
        struct net_device **vlan_devices_arrays[VLAN_GROUP_ARRAY_SPLIT_PARTS];
        struct rcu_head         rcu;
};

static inline struct net_device *vlan_group_get_device(struct vlan_group *vg,
                                                       unsigned int vlan_id)
{
        struct net_device **array;
        array = vg->vlan_devices_arrays[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
        return array ? array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] : NULL;
}

static inline void vlan_group_set_device(struct vlan_group *vg,
                                         unsigned int vlan_id,
                                         struct net_device *dev)
{
        struct net_device **array;
        if (!vg)
                return;
        array = vg->vlan_devices_arrays[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
        array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] = dev;
}

struct vlan_priority_tci_mapping {
        u32 priority;
        unsigned short vlan_qos; /* This should be shifted when first set, so we only do it
                                  * at provisioning time.
                                  * ((skb->priority << 13) & 0xE000)
                                  */
        struct vlan_priority_tci_mapping *next;
};

/* Holds information that makes sense if this device is a VLAN device. */
struct vlan_dev_info {
        /** This will be the mapping that correlates skb->priority to
         * 3 bits of VLAN QOS tags...
         */
        unsigned int nr_ingress_mappings;
        u32 ingress_priority_map[8];

        unsigned int nr_egress_mappings;
        struct vlan_priority_tci_mapping *egress_priority_map[16]; /* hash table */

        unsigned short vlan_id;        /*  The VLAN Identifier for this interface. */
        unsigned short flags;          /* (1 << 0) re_order_header   This option will cause the
                                        *   VLAN code to move around the ethernet header on
                                        *   ingress to make the skb look **exactly** like it
                                        *   came in from an ethernet port.  This destroys some of
                                        *   the VLAN information in the skb, but it fixes programs
                                        *   like DHCP that use packet-filtering and don't understand
                                        *   802.1Q
                                        */
        struct net_device *real_dev;    /* the underlying device/interface */
        unsigned char real_dev_addr[ETH_ALEN];
        struct proc_dir_entry *dent;    /* Holds the proc data */
        unsigned long cnt_inc_headroom_on_tx; /* How many times did we have to grow the skb on TX. */
        unsigned long cnt_encap_on_xmit;      /* How many times did we have to encapsulate the skb on TX. */
};

static inline struct vlan_dev_info *vlan_dev_info(const struct net_device *dev)
{
        return netdev_priv(dev);
}

/* inline functions */
static inline __u32 vlan_get_ingress_priority(struct net_device *dev,
                                              unsigned short vlan_tag)
{
        struct vlan_dev_info *vip = vlan_dev_info(dev);

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

/* VLAN tx hw acceleration helpers. */
struct vlan_skb_tx_cookie {
        u32     magic;
        u32     vlan_tag;
};

#define VLAN_TX_COOKIE_MAGIC    0x564c414e      /* "VLAN" in ascii. */
#define VLAN_TX_SKB_CB(__skb)   ((struct vlan_skb_tx_cookie *)&((__skb)->cb[0]))
#define vlan_tx_tag_present(__skb) \
        (VLAN_TX_SKB_CB(__skb)->magic == VLAN_TX_COOKIE_MAGIC)
#define vlan_tx_tag_get(__skb)  (VLAN_TX_SKB_CB(__skb)->vlan_tag)

/* VLAN rx hw acceleration helper.  This acts like netif_{rx,receive_skb}(). */
static inline int __vlan_hwaccel_rx(struct sk_buff *skb,
                                    struct vlan_group *grp,
                                    unsigned short vlan_tag, int polling)
{
        struct net_device_stats *stats;

        if (skb_bond_should_drop(skb)) {
                dev_kfree_skb_any(skb);
                return NET_RX_DROP;
        }

        skb->dev = vlan_group_get_device(grp, vlan_tag & VLAN_VID_MASK);
        if (skb->dev == NULL) {
                dev_kfree_skb_any(skb);

                /* Not NET_RX_DROP, this is not being dropped
                 * due to congestion.
                 */
                return 0;
        }

        skb->dev->last_rx = jiffies;

        stats = &skb->dev->stats;
        stats->rx_packets++;
        stats->rx_bytes += skb->len;

        skb->priority = vlan_get_ingress_priority(skb->dev, vlan_tag);
        switch (skb->pkt_type) {
        case PACKET_BROADCAST:
                break;

        case PACKET_MULTICAST:
                stats->multicast++;
                break;

        case PACKET_OTHERHOST:
                /* Our lower layer thinks this is not local, let's make sure.
                 * This allows the VLAN to have a different MAC than the underlying
                 * device, and still route correctly.
                 */
                if (!compare_ether_addr(eth_hdr(skb)->h_dest,
                                        skb->dev->dev_addr))
                        skb->pkt_type = PACKET_HOST;
                break;
        };

        return (polling ? netif_receive_skb(skb) : netif_rx(skb));
}

static inline int vlan_hwaccel_rx(struct sk_buff *skb,
                                  struct vlan_group *grp,
                                  unsigned short vlan_tag)
{
        return __vlan_hwaccel_rx(skb, grp, vlan_tag, 0);
}

static inline int vlan_hwaccel_receive_skb(struct sk_buff *skb,
                                           struct vlan_group *grp,
                                           unsigned short vlan_tag)
{
        return __vlan_hwaccel_rx(skb, grp, vlan_tag, 1);
}

/**
 * __vlan_put_tag - regular VLAN tag inserting
 * @skb: skbuff to tag
 * @tag: VLAN tag 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, unsigned short tag)
{
        struct vlan_ethhdr *veth;

        if (skb_headroom(skb) < VLAN_HLEN) {
                struct sk_buff *sk_tmp = skb;
                skb = skb_realloc_headroom(sk_tmp, VLAN_HLEN);
                kfree_skb(sk_tmp);
                if (!skb) {
                        printk(KERN_ERR "vlan: failed to realloc headroom\n");
                        return NULL;
                }
        } else {
                skb = skb_unshare(skb, GFP_ATOMIC);
                if (!skb) {
                        printk(KERN_ERR "vlan: failed to unshare skbuff\n");
                        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 * VLAN_ETH_ALEN);

        /* first, the ethernet type */
        veth->h_vlan_proto = htons(ETH_P_8021Q);

        /* now, the tag */
        veth->h_vlan_TCI = htons(tag);

        skb->protocol = htons(ETH_P_8021Q);
        skb->mac_header -= VLAN_HLEN;
        skb->network_header -= VLAN_HLEN;

        return skb;
}

/**
 * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
 * @skb: skbuff to tag
 * @tag: VLAN tag to insert
 *
 * Puts the VLAN tag in @skb->cb[] and lets the device do the rest
 */
static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb, unsigned short tag)
{
        struct vlan_skb_tx_cookie *cookie;

        cookie = VLAN_TX_SKB_CB(skb);
        cookie->magic = VLAN_TX_COOKIE_MAGIC;
        cookie->vlan_tag = tag;

        return skb;
}

#define HAVE_VLAN_PUT_TAG

/**
 * vlan_put_tag - inserts VLAN tag according to device features
 * @skb: skbuff to tag
 * @tag: VLAN tag 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, unsigned short tag)
{
        if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
                return __vlan_hwaccel_put_tag(skb, tag);
        } else {
                return __vlan_put_tag(skb, tag);
        }
}

/**
 * __vlan_get_tag - get the VLAN ID that is part of the payload
 * @skb: skbuff to query
 * @tag: 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, unsigned short *tag)
{
        struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;

        if (veth->h_vlan_proto != htons(ETH_P_8021Q)) {
                return -EINVAL;
        }

        *tag = ntohs(veth->h_vlan_TCI);

        return 0;
}

/**
 * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
 * @skb: skbuff to query
 * @tag: buffer to store vlaue
 * 
 * Returns error if @skb->cb[] is not set correctly
 */
static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
                                         unsigned short *tag)
{
        struct vlan_skb_tx_cookie *cookie;

        cookie = VLAN_TX_SKB_CB(skb);
        if (cookie->magic == VLAN_TX_COOKIE_MAGIC) {
                *tag = cookie->vlan_tag;
                return 0;
        } else {
                *tag = 0;
                return -EINVAL;
        }
}

#define HAVE_VLAN_GET_TAG

/**
 * vlan_get_tag - get the VLAN ID from the skb
 * @skb: skbuff to query
 * @tag: buffer to store vlaue
 * 
 * Returns error if the skb is not VLAN tagged
 */
static inline int vlan_get_tag(const struct sk_buff *skb, unsigned short *tag)
{
        if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
                return __vlan_hwaccel_get_tag(skb, tag);
        } else {
                return __vlan_get_tag(skb, tag);
        }
}

#endif /* __KERNEL__ */

/* VLAN IOCTLs are found in sockios.h */

/* Passed in vlan_ioctl_args structure to determine behaviour. */
enum vlan_ioctl_cmds {
        ADD_VLAN_CMD,
        DEL_VLAN_CMD,
        SET_VLAN_INGRESS_PRIORITY_CMD,
        SET_VLAN_EGRESS_PRIORITY_CMD,
        GET_VLAN_INGRESS_PRIORITY_CMD,
        GET_VLAN_EGRESS_PRIORITY_CMD,
        SET_VLAN_NAME_TYPE_CMD,
        SET_VLAN_FLAG_CMD,
        GET_VLAN_REALDEV_NAME_CMD, /* If this works, you know it's a VLAN device, btw */
        GET_VLAN_VID_CMD /* Get the VID of this VLAN (specified by name) */
};

enum vlan_flags {
        VLAN_FLAG_REORDER_HDR   = 0x1,
};

enum vlan_name_types {
        VLAN_NAME_TYPE_PLUS_VID, /* Name will look like:  vlan0005 */
        VLAN_NAME_TYPE_RAW_PLUS_VID, /* name will look like:  eth1.0005 */
        VLAN_NAME_TYPE_PLUS_VID_NO_PAD, /* Name will look like:  vlan5 */
        VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD, /* Name will look like:  eth0.5 */
        VLAN_NAME_TYPE_HIGHEST
};

struct vlan_ioctl_args {
        int cmd; /* Should be one of the vlan_ioctl_cmds enum above. */
        char device1[24];

        union {
                char device2[24];
                int VID;
                unsigned int skb_priority;
                unsigned int name_type;
                unsigned int bind_type;
                unsigned int flag; /* Matches vlan_dev_info flags */
        } u;

        short vlan_qos;   
};

#endif /* !(_LINUX_IF_VLAN_H_) */