// 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 "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);
        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. */
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)
                pr_warn("failed to kill vid %04x/%d for device %s\n",
                        proto, vid, dev->name);

        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) {
                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) {
                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)
                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_fast(skb, off_vlan);
        if (skb_gro_header_hard(skb, hlen)) {
                vhdr = skb_gro_header_slow(skb, hlen, off_vlan);
                if (unlikely(!vhdr))
                        goto out;
        }

        type = vhdr->h_vlan_encapsulated_proto;

        rcu_read_lock();
        ptype = gro_find_receive_by_type(type);
        if (!ptype)
                goto out_unlock;

        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 = call_gro_receive(ptype->callbacks.gro_receive, head, skb);

out_unlock:
        rcu_read_unlock();
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;

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

        rcu_read_unlock();
        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);