vlan_core.c

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#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;
    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)
        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 (ether_addr_equal(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;
    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);
    skb_reset_mac_len(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);

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);