#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_vlan.h>
#include <linux/netpoll.h>
#include <linux/export.h>
#include "vlan.h"

bool vlan_do_receive(struct sk_buff **skbp, bool last_handler)
{
        struct sk_buff *skb = *skbp;
        u16 vlan_id = skb->vlan_tci & VLAN_VID_MASK;
        struct net_device *vlan_dev;
        struct vlan_pcpu_stats *rx_stats;

        vlan_dev = vlan_find_dev(skb->dev, vlan_id);
        if (!vlan_dev) {
                /* Only the last call to vlan_do_receive() should change
                 * pkt_type to PACKET_OTHERHOST
                 */
                if (vlan_id && last_handler)
                        skb->pkt_type = PACKET_OTHERHOST;
                return false;
        }

        skb = *skbp = skb_share_check(skb, GFP_ATOMIC);
        if (unlikely(!skb))
                return false;

        skb->dev = vlan_dev;
        if (skb->pkt_type == 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,
                                        vlan_dev->dev_addr))
                        skb->pkt_type = PACKET_HOST;
        }

        if (!(vlan_dev_priv(vlan_dev)->flags & VLAN_FLAG_REORDER_HDR)) {
                unsigned int offset = skb->data - skb_mac_header(skb);

                /*
                 * vlan_insert_tag expect skb->data pointing to mac header.
                 * So change skb->data before calling it and change back to
                 * original position later
                 */
                skb_push(skb, offset);
                skb = *skbp = vlan_insert_tag(skb, skb->vlan_tci);
                if (!skb)
                        return false;
                skb_pull(skb, offset + VLAN_HLEN);
                skb_reset_mac_len(skb);
        }

        skb->priority = vlan_get_ingress_priority(vlan_dev, skb->vlan_tci);
        skb->vlan_tci = 0;

        rx_stats = this_cpu_ptr(vlan_dev_priv(vlan_dev)->vlan_pcpu_stats);

        u64_stats_update_begin(&rx_stats->syncp);
        rx_stats->rx_packets++;
        rx_stats->rx_bytes += skb->len;
        if (skb->pkt_type == PACKET_MULTICAST)
                rx_stats->rx_multicast++;
        u64_stats_update_end(&rx_stats->syncp);

        return true;
}

/* Must be invoked with rcu_read_lock or with RTNL. */
struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
                                        u16 vlan_id)
{
        struct vlan_info *vlan_info = rcu_dereference_rtnl(real_dev->vlan_info);

        if (vlan_info) {
                return vlan_group_get_device(&vlan_info->grp, vlan_id);
        } else {
                /*
                 * Bonding slaves do not have grp assigned to themselves.
                 * Grp is assigned to bonding master instead.
                 */
                if (netif_is_bond_slave(real_dev))
                        return __vlan_find_dev_deep(real_dev->master, vlan_id);
        }

        return NULL;
}
EXPORT_SYMBOL(__vlan_find_dev_deep);

struct net_device *vlan_dev_real_dev(const struct net_device *dev)
{
        return vlan_dev_priv(dev)->real_dev;
}
EXPORT_SYMBOL(vlan_dev_real_dev);

u16 vlan_dev_vlan_id(const struct net_device *dev)
{
        return vlan_dev_priv(dev)->vlan_id;
}
EXPORT_SYMBOL(vlan_dev_vlan_id);

static struct sk_buff *vlan_reorder_header(struct sk_buff *skb)
{
        if (skb_cow(skb, skb_headroom(skb)) < 0)
                return NULL;
        memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
        skb->mac_header += VLAN_HLEN;
        skb_reset_mac_len(skb);
        return skb;
}

struct sk_buff *vlan_untag(struct sk_buff *skb)
{
        struct vlan_hdr *vhdr;
        u16 vlan_tci;

        if (unlikely(vlan_tx_tag_present(skb))) {
                /* vlan_tci is already set-up so leave this for another time */
                return skb;
        }

        skb = skb_share_check(skb, GFP_ATOMIC);
        if (unlikely(!skb))
                goto err_free;

        if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
                goto err_free;

        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);
        vlan_set_encap_proto(skb, vhdr);

        skb = vlan_reorder_header(skb);
        if (unlikely(!skb))
                goto err_free;

        skb_reset_network_header(skb);
        skb_reset_transport_header(skb);
        return skb;

err_free:
        kfree_skb(skb);
        return NULL;
}


/*
 * vlan info and vid list
 */

static void vlan_group_free(struct vlan_group *grp)
{
        int i;

        for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++)
                kfree(grp->vlan_devices_arrays[i]);
}

static void vlan_info_free(struct vlan_info *vlan_info)
{
        vlan_group_free(&vlan_info->grp);
        kfree(vlan_info);
}

static void vlan_info_rcu_free(struct rcu_head *rcu)
{
        vlan_info_free(container_of(rcu, struct vlan_info, rcu));
}

static struct vlan_info *vlan_info_alloc(struct net_device *dev)
{
        struct vlan_info *vlan_info;

        vlan_info = kzalloc(sizeof(struct vlan_info), GFP_KERNEL);
        if (!vlan_info)
                return NULL;

        vlan_info->real_dev = dev;
        INIT_LIST_HEAD(&vlan_info->vid_list);
        return vlan_info;
}

struct vlan_vid_info {
        struct list_head list;
        unsigned short vid;
        int refcount;
};

static struct vlan_vid_info *vlan_vid_info_get(struct vlan_info *vlan_info,
                                               unsigned short vid)
{
        struct vlan_vid_info *vid_info;

        list_for_each_entry(vid_info, &vlan_info->vid_list, list) {
                if (vid_info->vid == vid)
                        return vid_info;
        }
        return NULL;
}

static struct vlan_vid_info *vlan_vid_info_alloc(unsigned short vid)
{
        struct vlan_vid_info *vid_info;

        vid_info = kzalloc(sizeof(struct vlan_vid_info), GFP_KERNEL);
        if (!vid_info)
                return NULL;
        vid_info->vid = vid;

        return vid_info;
}

static int __vlan_vid_add(struct vlan_info *vlan_info, unsigned short vid,
                          struct vlan_vid_info **pvid_info)
{
        struct net_device *dev = vlan_info->real_dev;
        const struct net_device_ops *ops = dev->netdev_ops;
        struct vlan_vid_info *vid_info;
        int err;

        vid_info = vlan_vid_info_alloc(vid);
        if (!vid_info)
                return -ENOMEM;

        if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
            ops->ndo_vlan_rx_add_vid) {
                err =  ops->ndo_vlan_rx_add_vid(dev, vid);
                if (err) {
                        kfree(vid_info);
                        return err;
                }
        }
        list_add(&vid_info->list, &vlan_info->vid_list);
        vlan_info->nr_vids++;
        *pvid_info = vid_info;
        return 0;
}

int vlan_vid_add(struct net_device *dev, unsigned short vid)
{
        struct vlan_info *vlan_info;
        struct vlan_vid_info *vid_info;
        bool vlan_info_created = false;
        int err;

        ASSERT_RTNL();

        vlan_info = rtnl_dereference(dev->vlan_info);
        if (!vlan_info) {
                vlan_info = vlan_info_alloc(dev);
                if (!vlan_info)
                        return -ENOMEM;
                vlan_info_created = true;
        }
        vid_info = vlan_vid_info_get(vlan_info, vid);
        if (!vid_info) {
                err = __vlan_vid_add(vlan_info, vid, &vid_info);
                if (err)
                        goto out_free_vlan_info;
        }
        vid_info->refcount++;

        if (vlan_info_created)
                rcu_assign_pointer(dev->vlan_info, vlan_info);

        return 0;

out_free_vlan_info:
        if (vlan_info_created)
                kfree(vlan_info);
        return err;
}
EXPORT_SYMBOL(vlan_vid_add);

static void __vlan_vid_del(struct vlan_info *vlan_info,
                           struct vlan_vid_info *vid_info)
{
        struct net_device *dev = vlan_info->real_dev;
        const struct net_device_ops *ops = dev->netdev_ops;
        unsigned short vid = vid_info->vid;
        int err;

        if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
             ops->ndo_vlan_rx_kill_vid) {
                err = ops->ndo_vlan_rx_kill_vid(dev, vid);
                if (err) {
                        pr_warn("failed to kill vid %d for device %s\n",
                                vid, dev->name);
                }
        }
        list_del(&vid_info->list);
        kfree(vid_info);
        vlan_info->nr_vids--;
}

void vlan_vid_del(struct net_device *dev, unsigned short vid)
{
        struct vlan_info *vlan_info;
        struct vlan_vid_info *vid_info;

        ASSERT_RTNL();

        vlan_info = rtnl_dereference(dev->vlan_info);
        if (!vlan_info)
                return;

        vid_info = vlan_vid_info_get(vlan_info, vid);
        if (!vid_info)
                return;
        vid_info->refcount--;
        if (vid_info->refcount == 0) {
                __vlan_vid_del(vlan_info, vid_info);
                if (vlan_info->nr_vids == 0) {
                        RCU_INIT_POINTER(dev->vlan_info, NULL);
                        call_rcu(&vlan_info->rcu, vlan_info_rcu_free);
                }
        }
}
EXPORT_SYMBOL(vlan_vid_del);

int vlan_vids_add_by_dev(struct net_device *dev,
                         const struct net_device *by_dev)
{
        struct vlan_vid_info *vid_info;
        struct vlan_info *vlan_info;
        int err;

        ASSERT_RTNL();

        vlan_info = rtnl_dereference(by_dev->vlan_info);
        if (!vlan_info)
                return 0;

        list_for_each_entry(vid_info, &vlan_info->vid_list, list) {
                err = vlan_vid_add(dev, vid_info->vid);
                if (err)
                        goto unwind;
        }
        return 0;

unwind:
        list_for_each_entry_continue_reverse(vid_info,
                                             &vlan_info->vid_list,
                                             list) {
                vlan_vid_del(dev, vid_info->vid);
        }

        return err;
}
EXPORT_SYMBOL(vlan_vids_add_by_dev);

void vlan_vids_del_by_dev(struct net_device *dev,
                          const struct net_device *by_dev)
{
        struct vlan_vid_info *vid_info;
        struct vlan_info *vlan_info;

        ASSERT_RTNL();

        vlan_info = rtnl_dereference(by_dev->vlan_info);
        if (!vlan_info)
                return;

        list_for_each_entry(vid_info, &vlan_info->vid_list, list)
                vlan_vid_del(dev, vid_info->vid);
}
EXPORT_SYMBOL(vlan_vids_del_by_dev);