// SPDX-License-Identifier: GPL-2.0
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_vlan.h>
#include <linux/netpoll.h>
#include <linux/export.h>
#include <net/gro.h>
#include "vlan.h"

bool vlan_do_receive(struct sk_buff **skbp)
{
 struct sk_buff *skb = *skbp;
 __be16 vlan_proto = skb->vlan_proto;
 u16 vlan_id = skb_vlan_tag_get_id(skb);
 struct net_device *vlan_dev;
 struct vlan_pcpu_stats *rx_stats;

 vlan_dev = vlan_find_dev(skb->dev, vlan_proto, vlan_id);
 if (!vlan_dev)
  return false;

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

 if (unlikely(!(vlan_dev->flags & IFF_UP))) {
  kfree_skb(skb);
  *skbp = NULL;
  return false;
 }

 skb->dev = vlan_dev;
 if (unlikely(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 (ether_addr_equal_64bits(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) &&
     !netif_is_macvlan_port(vlan_dev) &&
     !netif_is_bridge_port(vlan_dev)) {
  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_inner_tag(skb, skb->vlan_proto,
          skb->vlan_tci, skb->mac_len);
  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);
 __vlan_hwaccel_clear_tag(skb);

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

 u64_stats_update_begin(&rx_stats->syncp);
 u64_stats_inc(&rx_stats->rx_packets);
 u64_stats_add(&rx_stats->rx_bytes, skb->len);
 if (skb->pkt_type == PACKET_MULTICAST)
  u64_stats_inc(&rx_stats->rx_multicast);
 u64_stats_update_end(&rx_stats->syncp);

 return true;
}

/* Must be invoked with rcu_read_lock. */
struct net_device *__vlan_find_dev_deep_rcu(struct net_device *dev,
     __be16 vlan_proto, u16 vlan_id)
{
 struct vlan_info *vlan_info = rcu_dereference(dev->vlan_info);

 if (vlan_info) {
  return vlan_group_get_device(&vlan_info->grp,
          vlan_proto, vlan_id);
 } else {
  /*
   * Lower devices of master uppers (bonding, team) do not have
   * grp assigned to themselves. Grp is assigned to upper device
   * instead.
 */
  struct net_device *upper_dev;

  upper_dev = netdev_master_upper_dev_get_rcu(dev);
  if (upper_dev)
   return __vlan_find_dev_deep_rcu(upper_dev,
          vlan_proto, vlan_id);
 }

 return NULL;
}
EXPORT_SYMBOL(__vlan_find_dev_deep_rcu);

struct net_device *vlan_dev_real_dev(const struct net_device *dev)
{
 struct net_device *ret = vlan_dev_priv(dev)->real_dev;

 while (is_vlan_dev(ret))
  ret = vlan_dev_priv(ret)->real_dev;

 return ret;
}
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);

__be16 vlan_dev_vlan_proto(const struct net_device *dev)
{
 return vlan_dev_priv(dev)->vlan_proto;
}
EXPORT_SYMBOL(vlan_dev_vlan_proto);

/*
 * vlan info and vid list
 */

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

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

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;
 __be16 proto;
 u16 vid;
 int refcount;
};

static bool vlan_hw_filter_capable(const struct net_device *dev, __be16 proto)
{
 if (proto == htons(ETH_P_8021Q) &&
     dev->features & NETIF_F_HW_VLAN_CTAG_FILTER)
  return true;
 if (proto == htons(ETH_P_8021AD) &&
     dev->features & NETIF_F_HW_VLAN_STAG_FILTER)
  return true;
 return false;
}

static struct vlan_vid_info *vlan_vid_info_get(struct vlan_info *vlan_info,
            __be16 proto, u16 vid)
{
 struct vlan_vid_info *vid_info;

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

static struct vlan_vid_info *vlan_vid_info_alloc(__be16 proto, u16 vid)
{
 struct vlan_vid_info *vid_info;

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

 return vid_info;
}

static int vlan_add_rx_filter_info(struct net_device *dev, __be16 proto, u16 vid)
{
 if (!vlan_hw_filter_capable(dev, proto))
  return 0;

 if (netif_device_present(dev))
  return dev->netdev_ops->ndo_vlan_rx_add_vid(dev, proto, vid);
 else
  return -ENODEV;
}

static int vlan_kill_rx_filter_info(struct net_device *dev, __be16 proto, u16 vid)
{
 if (!vlan_hw_filter_capable(dev, proto))
  return 0;

 if (netif_device_present(dev))
  return dev->netdev_ops->ndo_vlan_rx_kill_vid(dev, proto, vid);
 else
  return -ENODEV;
}

int vlan_for_each(struct net_device *dev,
    int (*action)(struct net_device *dev, int vid, void *arg),
    void *arg)
{
 struct vlan_vid_info *vid_info;
 struct vlan_info *vlan_info;
 struct net_device *vdev;
 int ret;

 ASSERT_RTNL();

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

 list_for_each_entry(vid_info, &vlan_info->vid_list, list) {
  vdev = vlan_group_get_device(&vlan_info->grp, vid_info->proto,
          vid_info->vid);
  ret = action(vdev, vid_info->vid, arg);
  if (ret)
   return ret;
 }

 return 0;
}
EXPORT_SYMBOL(vlan_for_each);

int vlan_filter_push_vids(struct vlan_info *vlan_info, __be16 proto)
{
 struct net_device *real_dev = vlan_info->real_dev;
 struct vlan_vid_info *vlan_vid_info;
 int err;

 list_for_each_entry(vlan_vid_info, &vlan_info->vid_list, list) {
  if (vlan_vid_info->proto == proto) {
   err = vlan_add_rx_filter_info(real_dev, proto,
            vlan_vid_info->vid);
   if (err)
    goto unwind;
  }
 }

 return 0;

unwind:
 list_for_each_entry_continue_reverse(vlan_vid_info,
          &vlan_info->vid_list, list) {
  if (vlan_vid_info->proto == proto)
   vlan_kill_rx_filter_info(real_dev, proto,
       vlan_vid_info->vid);
 }

 return err;
}
EXPORT_SYMBOL(vlan_filter_push_vids);

void vlan_filter_drop_vids(struct vlan_info *vlan_info, __be16 proto)
{
 struct vlan_vid_info *vlan_vid_info;

 list_for_each_entry(vlan_vid_info, &vlan_info->vid_list, list)
  if (vlan_vid_info->proto == proto)
   vlan_kill_rx_filter_info(vlan_info->real_dev,
       vlan_vid_info->proto,
       vlan_vid_info->vid);
}
EXPORT_SYMBOL(vlan_filter_drop_vids);

static int __vlan_vid_add(struct vlan_info *vlan_info, __be16 proto, u16 vid,
     struct vlan_vid_info **pvid_info)
{
 struct net_device *dev = vlan_info->real_dev;
 struct vlan_vid_info *vid_info;
 int err;

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

 err = vlan_add_rx_filter_info(dev, proto, 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, __be16 proto, u16 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, proto, vid);
 if (!vid_info) {
  err = __vlan_vid_add(vlan_info, proto, 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;
 __be16 proto = vid_info->proto;
 u16 vid = vid_info->vid;
 int err;

 err = vlan_kill_rx_filter_info(dev, proto, vid);
 if (err && dev->reg_state != NETREG_UNREGISTERING)
  netdev_warn(dev, "failed to kill vid %04x/%d\n", proto, vid);

 list_del(&vid_info->list);
 kfree(vid_info);
 vlan_info->nr_vids--;
}

void vlan_vid_del(struct net_device *dev, __be16 proto, u16 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, proto, 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) {
  if (!vlan_hw_filter_capable(by_dev, vid_info->proto))
   continue;
  err = vlan_vid_add(dev, vid_info->proto, vid_info->vid);
  if (err)
   goto unwind;
 }
 return 0;

unwind:
 list_for_each_entry_continue_reverse(vid_info,
          &vlan_info->vid_list,
          list) {
  if (!vlan_hw_filter_capable(by_dev, vid_info->proto))
   continue;
  vlan_vid_del(dev, vid_info->proto, 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) {
  if (!vlan_hw_filter_capable(by_dev, vid_info->proto))
   continue;
  vlan_vid_del(dev, vid_info->proto, vid_info->vid);
 }
}
EXPORT_SYMBOL(vlan_vids_del_by_dev);

bool vlan_uses_dev(const struct net_device *dev)
{
 struct vlan_info *vlan_info;

 ASSERT_RTNL();

 vlan_info = rtnl_dereference(dev->vlan_info);
 if (!vlan_info)
  return false;
 return vlan_info->grp.nr_vlan_devs ? true : false;
}
EXPORT_SYMBOL(vlan_uses_dev);

static struct sk_buff *vlan_gro_receive(struct list_head *head,
     struct sk_buff *skb)
{
 const struct packet_offload *ptype;
 unsigned int hlen, off_vlan;
 struct sk_buff *pp = NULL;
 struct vlan_hdr *vhdr;
 struct sk_buff *p;
 __be16 type;
 int flush = 1;

 off_vlan = skb_gro_offset(skb);
 hlen = off_vlan + sizeof(*vhdr);
 vhdr = skb_gro_header(skb, hlen, off_vlan);
 if (unlikely(!vhdr))
  goto out;

 NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = hlen;

 type = vhdr->h_vlan_encapsulated_proto;

 ptype = gro_find_receive_by_type(type);
 if (!ptype)
  goto out;

 flush = 0;

 list_for_each_entry(p, head, list) {
  struct vlan_hdr *vhdr2;

  if (!NAPI_GRO_CB(p)->same_flow)
   continue;

  vhdr2 = (struct vlan_hdr *)(p->data + off_vlan);
  if (compare_vlan_header(vhdr, vhdr2))
   NAPI_GRO_CB(p)->same_flow = 0;
 }

 skb_gro_pull(skb, sizeof(*vhdr));
 skb_gro_postpull_rcsum(skb, vhdr, sizeof(*vhdr));

 pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
         ipv6_gro_receive, inet_gro_receive,
         head, skb);

out:
 skb_gro_flush_final(skb, pp, flush);

 return pp;
}

static int vlan_gro_complete(struct sk_buff *skb, int nhoff)
{
 struct vlan_hdr *vhdr = (struct vlan_hdr *)(skb->data + nhoff);
 __be16 type = vhdr->h_vlan_encapsulated_proto;
 struct packet_offload *ptype;
 int err = -ENOENT;

 ptype = gro_find_complete_by_type(type);
 if (ptype)
  err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
      ipv6_gro_complete, inet_gro_complete,
      skb, nhoff + sizeof(*vhdr));

 return err;
}

static struct packet_offload vlan_packet_offloads[] __read_mostly = {
 {
  .type = cpu_to_be16(ETH_P_8021Q),
  .priority = 10,
  .callbacks = {
   .gro_receive = vlan_gro_receive,
   .gro_complete = vlan_gro_complete,
  },
 },
 {
  .type = cpu_to_be16(ETH_P_8021AD),
  .priority = 10,
  .callbacks = {
   .gro_receive = vlan_gro_receive,
   .gro_complete = vlan_gro_complete,
  },
 },
};

static int __init vlan_offload_init(void)
{
 unsigned int i;

 for (i = 0; i < ARRAY_SIZE(vlan_packet_offloads); i++)
  dev_add_offload(&vlan_packet_offloads[i]);

 return 0;
}

fs_initcall(vlan_offload_init);