br2684.c

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/*
 * Ethernet netdevice using ATM AAL5 as underlying carrier
 * (RFC1483 obsoleted by RFC2684) for Linux
 *
 * Authors: Marcell GAL, 2000, XDSL Ltd, Hungary
 *          Eric Kinzie, 2006-2007, US Naval Research Laboratory
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/ip.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <net/arp.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/capability.h>
#include <linux/seq_file.h>

#include <linux/atmbr2684.h>

#include "common.h"

static void skb_debug(const struct sk_buff *skb)
{
#ifdef SKB_DEBUG
#define NUM2PRINT 50
    print_hex_dump(KERN_DEBUG, "br2684: skb: ", DUMP_OFFSET,
               16, 1, skb->data, min(NUM2PRINT, skb->len), true);
#endif
}

#define BR2684_ETHERTYPE_LEN    2
#define BR2684_PAD_LEN      2

#define LLC     0xaa, 0xaa, 0x03
#define SNAP_BRIDGED    0x00, 0x80, 0xc2
#define SNAP_ROUTED 0x00, 0x00, 0x00
#define PID_ETHERNET    0x00, 0x07
#define ETHERTYPE_IPV4  0x08, 0x00
#define ETHERTYPE_IPV6  0x86, 0xdd
#define PAD_BRIDGED 0x00, 0x00

static const unsigned char ethertype_ipv4[] = { ETHERTYPE_IPV4 };
static const unsigned char ethertype_ipv6[] = { ETHERTYPE_IPV6 };
static const unsigned char llc_oui_pid_pad[] =
            { LLC, SNAP_BRIDGED, PID_ETHERNET, PAD_BRIDGED };
static const unsigned char pad[] = { PAD_BRIDGED };
static const unsigned char llc_oui_ipv4[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV4 };
static const unsigned char llc_oui_ipv6[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV6 };

enum br2684_encaps {
    e_vc = BR2684_ENCAPS_VC,
    e_llc = BR2684_ENCAPS_LLC,
};

struct br2684_vcc {
    struct atm_vcc *atmvcc;
    struct net_device *device;
    /* keep old push, pop functions for chaining */
    void (*old_push)(struct atm_vcc *vcc, struct sk_buff *skb);
    void (*old_pop)(struct atm_vcc *vcc, struct sk_buff *skb);
    enum br2684_encaps encaps;
    struct list_head brvccs;
#ifdef CONFIG_ATM_BR2684_IPFILTER
    struct br2684_filter filter;
#endif /* CONFIG_ATM_BR2684_IPFILTER */
    unsigned int copies_needed, copies_failed;
};

struct br2684_dev {
    struct net_device *net_dev;
    struct list_head br2684_devs;
    int number;
    struct list_head brvccs;    /* one device <=> one vcc (before xmas) */
    int mac_was_set;
    enum br2684_payload payload;
};

/*
 * This lock should be held for writing any time the list of devices or
 * their attached vcc's could be altered.  It should be held for reading
 * any time these are being queried.  Note that we sometimes need to
 * do read-locking under interrupt context, so write locking must block
 * the current CPU's interrupts
 */
static DEFINE_RWLOCK(devs_lock);

static LIST_HEAD(br2684_devs);

static inline struct br2684_dev *BRPRIV(const struct net_device *net_dev)
{
    return netdev_priv(net_dev);
}

static inline struct net_device *list_entry_brdev(const struct list_head *le)
{
    return list_entry(le, struct br2684_dev, br2684_devs)->net_dev;
}

static inline struct br2684_vcc *BR2684_VCC(const struct atm_vcc *atmvcc)
{
    return (struct br2684_vcc *)(atmvcc->user_back);
}

static inline struct br2684_vcc *list_entry_brvcc(const struct list_head *le)
{
    return list_entry(le, struct br2684_vcc, brvccs);
}

/* Caller should hold read_lock(&devs_lock) */
static struct net_device *br2684_find_dev(const struct br2684_if_spec *s)
{
    struct list_head *lh;
    struct net_device *net_dev;
    switch (s->method) {
    case BR2684_FIND_BYNUM:
        list_for_each(lh, &br2684_devs) {
            net_dev = list_entry_brdev(lh);
            if (BRPRIV(net_dev)->number == s->spec.devnum)
                return net_dev;
        }
        break;
    case BR2684_FIND_BYIFNAME:
        list_for_each(lh, &br2684_devs) {
            net_dev = list_entry_brdev(lh);
            if (!strncmp(net_dev->name, s->spec.ifname, IFNAMSIZ))
                return net_dev;
        }
        break;
    }
    return NULL;
}

static int atm_dev_event(struct notifier_block *this, unsigned long event,
         void *arg)
{
    struct atm_dev *atm_dev = arg;
    struct list_head *lh;
    struct net_device *net_dev;
    struct br2684_vcc *brvcc;
    struct atm_vcc *atm_vcc;
    unsigned long flags;

    pr_debug("event=%ld dev=%p\n", event, atm_dev);

    read_lock_irqsave(&devs_lock, flags);
    list_for_each(lh, &br2684_devs) {
        net_dev = list_entry_brdev(lh);

        list_for_each_entry(brvcc, &BRPRIV(net_dev)->brvccs, brvccs) {
            atm_vcc = brvcc->atmvcc;
            if (atm_vcc && brvcc->atmvcc->dev == atm_dev) {

                if (atm_vcc->dev->signal == ATM_PHY_SIG_LOST)
                    netif_carrier_off(net_dev);
                else
                    netif_carrier_on(net_dev);

            }
        }
    }
    read_unlock_irqrestore(&devs_lock, flags);

    return NOTIFY_DONE;
}

static struct notifier_block atm_dev_notifier = {
    .notifier_call = atm_dev_event,
};

/* chained vcc->pop function.  Check if we should wake the netif_queue */
static void br2684_pop(struct atm_vcc *vcc, struct sk_buff *skb)
{
    struct br2684_vcc *brvcc = BR2684_VCC(vcc);
    struct net_device *net_dev = skb->dev;

    pr_debug("(vcc %p ; net_dev %p )\n", vcc, net_dev);
    brvcc->old_pop(vcc, skb);

    if (!net_dev)
        return;

    if (atm_may_send(vcc, 0))
        netif_wake_queue(net_dev);

}
/*
 * Send a packet out a particular vcc.  Not to useful right now, but paves
 * the way for multiple vcc's per itf.  Returns true if we can send,
 * otherwise false
 */
static int br2684_xmit_vcc(struct sk_buff *skb, struct net_device *dev,
               struct br2684_vcc *brvcc)
{
    struct br2684_dev *brdev = BRPRIV(dev);
    struct atm_vcc *atmvcc;
    int minheadroom = (brvcc->encaps == e_llc) ?
        ((brdev->payload == p_bridged) ?
            sizeof(llc_oui_pid_pad) : sizeof(llc_oui_ipv4)) :
        ((brdev->payload == p_bridged) ? BR2684_PAD_LEN : 0);

    if (skb_headroom(skb) < minheadroom) {
        struct sk_buff *skb2 = skb_realloc_headroom(skb, minheadroom);
        brvcc->copies_needed++;
        dev_kfree_skb(skb);
        if (skb2 == NULL) {
            brvcc->copies_failed++;
            return 0;
        }
        skb = skb2;
    }

    if (brvcc->encaps == e_llc) {
        if (brdev->payload == p_bridged) {
            skb_push(skb, sizeof(llc_oui_pid_pad));
            skb_copy_to_linear_data(skb, llc_oui_pid_pad,
                        sizeof(llc_oui_pid_pad));
        } else if (brdev->payload == p_routed) {
            unsigned short prot = ntohs(skb->protocol);

            skb_push(skb, sizeof(llc_oui_ipv4));
            switch (prot) {
            case ETH_P_IP:
                skb_copy_to_linear_data(skb, llc_oui_ipv4,
                            sizeof(llc_oui_ipv4));
                break;
            case ETH_P_IPV6:
                skb_copy_to_linear_data(skb, llc_oui_ipv6,
                            sizeof(llc_oui_ipv6));
                break;
            default:
                dev_kfree_skb(skb);
                return 0;
            }
        }
    } else { /* e_vc */
        if (brdev->payload == p_bridged) {
            skb_push(skb, 2);
            memset(skb->data, 0, 2);
        }
    }
    skb_debug(skb);

    ATM_SKB(skb)->vcc = atmvcc = brvcc->atmvcc;
    pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, atmvcc, atmvcc->dev);
    atomic_add(skb->truesize, &sk_atm(atmvcc)->sk_wmem_alloc);
    ATM_SKB(skb)->atm_options = atmvcc->atm_options;
    dev->stats.tx_packets++;
    dev->stats.tx_bytes += skb->len;
    atmvcc->send(atmvcc, skb);

    if (!atm_may_send(atmvcc, 0)) {
        netif_stop_queue(brvcc->device);
        /*check for race with br2684_pop*/
        if (atm_may_send(atmvcc, 0))
            netif_start_queue(brvcc->device);
    }

    return 1;
}

static inline struct br2684_vcc *pick_outgoing_vcc(const struct sk_buff *skb,
                           const struct br2684_dev *brdev)
{
    return list_empty(&brdev->brvccs) ? NULL : list_entry_brvcc(brdev->brvccs.next);    /* 1 vcc/dev right now */
}

static netdev_tx_t br2684_start_xmit(struct sk_buff *skb,
                     struct net_device *dev)
{
    struct br2684_dev *brdev = BRPRIV(dev);
    struct br2684_vcc *brvcc;

    pr_debug("skb_dst(skb)=%p\n", skb_dst(skb));
    read_lock(&devs_lock);
    brvcc = pick_outgoing_vcc(skb, brdev);
    if (brvcc == NULL) {
        pr_debug("no vcc attached to dev %s\n", dev->name);
        dev->stats.tx_errors++;
        dev->stats.tx_carrier_errors++;
        /* netif_stop_queue(dev); */
        dev_kfree_skb(skb);
        read_unlock(&devs_lock);
        return NETDEV_TX_OK;
    }
    if (!br2684_xmit_vcc(skb, dev, brvcc)) {
        /*
         * We should probably use netif_*_queue() here, but that
         * involves added complication.  We need to walk before
         * we can run.
         *
         * Don't free here! this pointer might be no longer valid!
         */
        dev->stats.tx_errors++;
        dev->stats.tx_fifo_errors++;
    }
    read_unlock(&devs_lock);
    return NETDEV_TX_OK;
}

/*
 * We remember when the MAC gets set, so we don't override it later with
 * the ESI of the ATM card of the first VC
 */
static int br2684_mac_addr(struct net_device *dev, void *p)
{
    int err = eth_mac_addr(dev, p);
    if (!err)
        BRPRIV(dev)->mac_was_set = 1;
    return err;
}

#ifdef CONFIG_ATM_BR2684_IPFILTER
/* this IOCTL is experimental. */
static int br2684_setfilt(struct atm_vcc *atmvcc, void __user * arg)
{
    struct br2684_vcc *brvcc;
    struct br2684_filter_set fs;

    if (copy_from_user(&fs, arg, sizeof fs))
        return -EFAULT;
    if (fs.ifspec.method != BR2684_FIND_BYNOTHING) {
        /*
         * This is really a per-vcc thing, but we can also search
         * by device.
         */
        struct br2684_dev *brdev;
        read_lock(&devs_lock);
        brdev = BRPRIV(br2684_find_dev(&fs.ifspec));
        if (brdev == NULL || list_empty(&brdev->brvccs) ||
            brdev->brvccs.next != brdev->brvccs.prev)   /* >1 VCC */
            brvcc = NULL;
        else
            brvcc = list_entry_brvcc(brdev->brvccs.next);
        read_unlock(&devs_lock);
        if (brvcc == NULL)
            return -ESRCH;
    } else
        brvcc = BR2684_VCC(atmvcc);
    memcpy(&brvcc->filter, &fs.filter, sizeof(brvcc->filter));
    return 0;
}

/* Returns 1 if packet should be dropped */
static inline int
packet_fails_filter(__be16 type, struct br2684_vcc *brvcc, struct sk_buff *skb)
{
    if (brvcc->filter.netmask == 0)
        return 0;   /* no filter in place */
    if (type == htons(ETH_P_IP) &&
        (((struct iphdr *)(skb->data))->daddr & brvcc->filter.
         netmask) == brvcc->filter.prefix)
        return 0;
    if (type == htons(ETH_P_ARP))
        return 0;
    /*
     * TODO: we should probably filter ARPs too.. don't want to have
     * them returning values that don't make sense, or is that ok?
     */
    return 1;       /* drop */
}
#endif /* CONFIG_ATM_BR2684_IPFILTER */

static void br2684_close_vcc(struct br2684_vcc *brvcc)
{
    pr_debug("removing VCC %p from dev %p\n", brvcc, brvcc->device);
    write_lock_irq(&devs_lock);
    list_del(&brvcc->brvccs);
    write_unlock_irq(&devs_lock);
    brvcc->atmvcc->user_back = NULL;    /* what about vcc->recvq ??? */
    brvcc->old_push(brvcc->atmvcc, NULL);   /* pass on the bad news */
    kfree(brvcc);
    module_put(THIS_MODULE);
}

/* when AAL5 PDU comes in: */
static void br2684_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
{
    struct br2684_vcc *brvcc = BR2684_VCC(atmvcc);
    struct net_device *net_dev = brvcc->device;
    struct br2684_dev *brdev = BRPRIV(net_dev);

    pr_debug("\n");

    if (unlikely(skb == NULL)) {
        /* skb==NULL means VCC is being destroyed */
        br2684_close_vcc(brvcc);
        if (list_empty(&brdev->brvccs)) {
            write_lock_irq(&devs_lock);
            list_del(&brdev->br2684_devs);
            write_unlock_irq(&devs_lock);
            unregister_netdev(net_dev);
            free_netdev(net_dev);
        }
        return;
    }

    skb_debug(skb);
    atm_return(atmvcc, skb->truesize);
    pr_debug("skb from brdev %p\n", brdev);
    if (brvcc->encaps == e_llc) {

        if (skb->len > 7 && skb->data[7] == 0x01)
            __skb_trim(skb, skb->len - 4);

        /* accept packets that have "ipv[46]" in the snap header */
        if ((skb->len >= (sizeof(llc_oui_ipv4))) &&
            (memcmp(skb->data, llc_oui_ipv4,
                sizeof(llc_oui_ipv4) - BR2684_ETHERTYPE_LEN) == 0)) {
            if (memcmp(skb->data + 6, ethertype_ipv6,
                   sizeof(ethertype_ipv6)) == 0)
                skb->protocol = htons(ETH_P_IPV6);
            else if (memcmp(skb->data + 6, ethertype_ipv4,
                    sizeof(ethertype_ipv4)) == 0)
                skb->protocol = htons(ETH_P_IP);
            else
                goto error;
            skb_pull(skb, sizeof(llc_oui_ipv4));
            skb_reset_network_header(skb);
            skb->pkt_type = PACKET_HOST;
        /*
         * Let us waste some time for checking the encapsulation.
         * Note, that only 7 char is checked so frames with a valid FCS
         * are also accepted (but FCS is not checked of course).
         */
        } else if ((skb->len >= sizeof(llc_oui_pid_pad)) &&
               (memcmp(skb->data, llc_oui_pid_pad, 7) == 0)) {
            skb_pull(skb, sizeof(llc_oui_pid_pad));
            skb->protocol = eth_type_trans(skb, net_dev);
        } else
            goto error;

    } else { /* e_vc */
        if (brdev->payload == p_routed) {
            struct iphdr *iph;

            skb_reset_network_header(skb);
            iph = ip_hdr(skb);
            if (iph->version == 4)
                skb->protocol = htons(ETH_P_IP);
            else if (iph->version == 6)
                skb->protocol = htons(ETH_P_IPV6);
            else
                goto error;
            skb->pkt_type = PACKET_HOST;
        } else { /* p_bridged */
            /* first 2 chars should be 0 */
            if (memcmp(skb->data, pad, BR2684_PAD_LEN) != 0)
                goto error;
            skb_pull(skb, BR2684_PAD_LEN);
            skb->protocol = eth_type_trans(skb, net_dev);
        }
    }

#ifdef CONFIG_ATM_BR2684_IPFILTER
    if (unlikely(packet_fails_filter(skb->protocol, brvcc, skb)))
        goto dropped;
#endif /* CONFIG_ATM_BR2684_IPFILTER */
    skb->dev = net_dev;
    ATM_SKB(skb)->vcc = atmvcc; /* needed ? */
    pr_debug("received packet's protocol: %x\n", ntohs(skb->protocol));
    skb_debug(skb);
    /* sigh, interface is down? */
    if (unlikely(!(net_dev->flags & IFF_UP)))
        goto dropped;
    net_dev->stats.rx_packets++;
    net_dev->stats.rx_bytes += skb->len;
    memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
    netif_rx(skb);
    return;

dropped:
    net_dev->stats.rx_dropped++;
    goto free_skb;
error:
    net_dev->stats.rx_errors++;
free_skb:
    dev_kfree_skb(skb);
}

/*
 * Assign a vcc to a dev
 * Note: we do not have explicit unassign, but look at _push()
 */
static int br2684_regvcc(struct atm_vcc *atmvcc, void __user * arg)
{
    struct br2684_vcc *brvcc;
    struct br2684_dev *brdev;
    struct net_device *net_dev;
    struct atm_backend_br2684 be;
    int err;

    if (copy_from_user(&be, arg, sizeof be))
        return -EFAULT;
    brvcc = kzalloc(sizeof(struct br2684_vcc), GFP_KERNEL);
    if (!brvcc)
        return -ENOMEM;
    write_lock_irq(&devs_lock);
    net_dev = br2684_find_dev(&be.ifspec);
    if (net_dev == NULL) {
        pr_err("tried to attach to non-existent device\n");
        err = -ENXIO;
        goto error;
    }
    brdev = BRPRIV(net_dev);
    if (atmvcc->push == NULL) {
        err = -EBADFD;
        goto error;
    }
    if (!list_empty(&brdev->brvccs)) {
        /* Only 1 VCC/dev right now */
        err = -EEXIST;
        goto error;
    }
    if (be.fcs_in != BR2684_FCSIN_NO ||
        be.fcs_out != BR2684_FCSOUT_NO ||
        be.fcs_auto || be.has_vpiid || be.send_padding ||
        (be.encaps != BR2684_ENCAPS_VC &&
         be.encaps != BR2684_ENCAPS_LLC) ||
        be.min_size != 0) {
        err = -EINVAL;
        goto error;
    }
    pr_debug("vcc=%p, encaps=%d, brvcc=%p\n", atmvcc, be.encaps, brvcc);
    if (list_empty(&brdev->brvccs) && !brdev->mac_was_set) {
        unsigned char *esi = atmvcc->dev->esi;
        if (esi[0] | esi[1] | esi[2] | esi[3] | esi[4] | esi[5])
            memcpy(net_dev->dev_addr, esi, net_dev->addr_len);
        else
            net_dev->dev_addr[2] = 1;
    }
    list_add(&brvcc->brvccs, &brdev->brvccs);
    write_unlock_irq(&devs_lock);
    brvcc->device = net_dev;
    brvcc->atmvcc = atmvcc;
    atmvcc->user_back = brvcc;
    brvcc->encaps = (enum br2684_encaps)be.encaps;
    brvcc->old_push = atmvcc->push;
    brvcc->old_pop = atmvcc->pop;
    barrier();
    atmvcc->push = br2684_push;
    atmvcc->pop = br2684_pop;

    /* initialize netdev carrier state */
    if (atmvcc->dev->signal == ATM_PHY_SIG_LOST)
        netif_carrier_off(net_dev);
    else
        netif_carrier_on(net_dev);

    __module_get(THIS_MODULE);

    /* re-process everything received between connection setup and
       backend setup */
    vcc_process_recv_queue(atmvcc);
    return 0;

error:
    write_unlock_irq(&devs_lock);
    kfree(brvcc);
    return err;
}

static const struct net_device_ops br2684_netdev_ops = {
    .ndo_start_xmit     = br2684_start_xmit,
    .ndo_set_mac_address    = br2684_mac_addr,
    .ndo_change_mtu     = eth_change_mtu,
    .ndo_validate_addr  = eth_validate_addr,
};

static const struct net_device_ops br2684_netdev_ops_routed = {
    .ndo_start_xmit     = br2684_start_xmit,
    .ndo_set_mac_address    = br2684_mac_addr,
    .ndo_change_mtu     = eth_change_mtu
};

static void br2684_setup(struct net_device *netdev)
{
    struct br2684_dev *brdev = BRPRIV(netdev);

    ether_setup(netdev);
    netdev->hard_header_len += sizeof(llc_oui_pid_pad); /* worst case */
    brdev->net_dev = netdev;

    netdev->netdev_ops = &br2684_netdev_ops;

    INIT_LIST_HEAD(&brdev->brvccs);
}

static void br2684_setup_routed(struct net_device *netdev)
{
    struct br2684_dev *brdev = BRPRIV(netdev);

    brdev->net_dev = netdev;
    netdev->hard_header_len = sizeof(llc_oui_ipv4); /* worst case */
    netdev->netdev_ops = &br2684_netdev_ops_routed;
    netdev->addr_len = 0;
    netdev->mtu = 1500;
    netdev->type = ARPHRD_PPP;
    netdev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
    netdev->tx_queue_len = 100;
    INIT_LIST_HEAD(&brdev->brvccs);
}

static int br2684_create(void __user *arg)
{
    int err;
    struct net_device *netdev;
    struct br2684_dev *brdev;
    struct atm_newif_br2684 ni;
    enum br2684_payload payload;

    pr_debug("\n");

    if (copy_from_user(&ni, arg, sizeof ni))
        return -EFAULT;

    if (ni.media & BR2684_FLAG_ROUTED)
        payload = p_routed;
    else
        payload = p_bridged;
    ni.media &= 0xffff; /* strip flags */

    if (ni.media != BR2684_MEDIA_ETHERNET || ni.mtu != 1500)
        return -EINVAL;

    netdev = alloc_netdev(sizeof(struct br2684_dev),
                  ni.ifname[0] ? ni.ifname : "nas%d",
                  (payload == p_routed) ?
                  br2684_setup_routed : br2684_setup);
    if (!netdev)
        return -ENOMEM;

    brdev = BRPRIV(netdev);

    pr_debug("registered netdev %s\n", netdev->name);
    /* open, stop, do_ioctl ? */
    err = register_netdev(netdev);
    if (err < 0) {
        pr_err("register_netdev failed\n");
        free_netdev(netdev);
        return err;
    }

    write_lock_irq(&devs_lock);

    brdev->payload = payload;

    if (list_empty(&br2684_devs)) {
        /* 1st br2684 device */
        brdev->number = 1;
    } else
        brdev->number = BRPRIV(list_entry_brdev(br2684_devs.prev))->number + 1;

    list_add_tail(&brdev->br2684_devs, &br2684_devs);
    write_unlock_irq(&devs_lock);
    return 0;
}

/*
 * This handles ioctls actually performed on our vcc - we must return
 * -ENOIOCTLCMD for any unrecognized ioctl
 */
static int br2684_ioctl(struct socket *sock, unsigned int cmd,
            unsigned long arg)
{
    struct atm_vcc *atmvcc = ATM_SD(sock);
    void __user *argp = (void __user *)arg;
    atm_backend_t b;

    int err;
    switch (cmd) {
    case ATM_SETBACKEND:
    case ATM_NEWBACKENDIF:
        err = get_user(b, (atm_backend_t __user *) argp);
        if (err)
            return -EFAULT;
        if (b != ATM_BACKEND_BR2684)
            return -ENOIOCTLCMD;
        if (!capable(CAP_NET_ADMIN))
            return -EPERM;
        if (cmd == ATM_SETBACKEND)
            return br2684_regvcc(atmvcc, argp);
        else
            return br2684_create(argp);
#ifdef CONFIG_ATM_BR2684_IPFILTER
    case BR2684_SETFILT:
        if (atmvcc->push != br2684_push)
            return -ENOIOCTLCMD;
        if (!capable(CAP_NET_ADMIN))
            return -EPERM;
        err = br2684_setfilt(atmvcc, argp);

        return err;
#endif /* CONFIG_ATM_BR2684_IPFILTER */
    }
    return -ENOIOCTLCMD;
}

static struct atm_ioctl br2684_ioctl_ops = {
    .owner = THIS_MODULE,
    .ioctl = br2684_ioctl,
};

#ifdef CONFIG_PROC_FS
static void *br2684_seq_start(struct seq_file *seq, loff_t * pos)
    __acquires(devs_lock)
{
    read_lock(&devs_lock);
    return seq_list_start(&br2684_devs, *pos);
}

static void *br2684_seq_next(struct seq_file *seq, void *v, loff_t * pos)
{
    return seq_list_next(v, &br2684_devs, pos);
}

static void br2684_seq_stop(struct seq_file *seq, void *v)
    __releases(devs_lock)
{
    read_unlock(&devs_lock);
}

static int br2684_seq_show(struct seq_file *seq, void *v)
{
    const struct br2684_dev *brdev = list_entry(v, struct br2684_dev,
                            br2684_devs);
    const struct net_device *net_dev = brdev->net_dev;
    const struct br2684_vcc *brvcc;

    seq_printf(seq, "dev %.16s: num=%d, mac=%pM (%s)\n",
           net_dev->name,
           brdev->number,
           net_dev->dev_addr,
           brdev->mac_was_set ? "set" : "auto");

    list_for_each_entry(brvcc, &brdev->brvccs, brvccs) {
        seq_printf(seq, "  vcc %d.%d.%d: encaps=%s payload=%s"
               ", failed copies %u/%u"
               "\n", brvcc->atmvcc->dev->number,
               brvcc->atmvcc->vpi, brvcc->atmvcc->vci,
               (brvcc->encaps == e_llc) ? "LLC" : "VC",
               (brdev->payload == p_bridged) ? "bridged" : "routed",
               brvcc->copies_failed, brvcc->copies_needed);
#ifdef CONFIG_ATM_BR2684_IPFILTER
#define b1(var, byte)   ((u8 *) &brvcc->filter.var)[byte]
#define bs(var)     b1(var, 0), b1(var, 1), b1(var, 2), b1(var, 3)
        if (brvcc->filter.netmask != 0)
            seq_printf(seq, "    filter=%d.%d.%d.%d/"
                   "%d.%d.%d.%d\n", bs(prefix), bs(netmask));
#undef bs
#undef b1
#endif /* CONFIG_ATM_BR2684_IPFILTER */
    }
    return 0;
}

static const struct seq_operations br2684_seq_ops = {
    .start = br2684_seq_start,
    .next = br2684_seq_next,
    .stop = br2684_seq_stop,
    .show = br2684_seq_show,
};

static int br2684_proc_open(struct inode *inode, struct file *file)
{
    return seq_open(file, &br2684_seq_ops);
}

static const struct file_operations br2684_proc_ops = {
    .owner = THIS_MODULE,
    .open = br2684_proc_open,
    .read = seq_read,
    .llseek = seq_lseek,
    .release = seq_release,
};

extern struct proc_dir_entry *atm_proc_root;    /* from proc.c */
#endif /* CONFIG_PROC_FS */

static int __init br2684_init(void)
{
#ifdef CONFIG_PROC_FS
    struct proc_dir_entry *p;
    p = proc_create("br2684", 0, atm_proc_root, &br2684_proc_ops);
    if (p == NULL)
        return -ENOMEM;
#endif
    register_atm_ioctl(&br2684_ioctl_ops);
    register_atmdevice_notifier(&atm_dev_notifier);
    return 0;
}

static void __exit br2684_exit(void)
{
    struct net_device *net_dev;
    struct br2684_dev *brdev;
    struct br2684_vcc *brvcc;
    deregister_atm_ioctl(&br2684_ioctl_ops);

#ifdef CONFIG_PROC_FS
    remove_proc_entry("br2684", atm_proc_root);
#endif


    unregister_atmdevice_notifier(&atm_dev_notifier);

    while (!list_empty(&br2684_devs)) {
        net_dev = list_entry_brdev(br2684_devs.next);
        brdev = BRPRIV(net_dev);
        while (!list_empty(&brdev->brvccs)) {
            brvcc = list_entry_brvcc(brdev->brvccs.next);
            br2684_close_vcc(brvcc);
        }

        list_del(&brdev->br2684_devs);
        unregister_netdev(net_dev);
        free_netdev(net_dev);
    }
}

module_init(br2684_init);
module_exit(br2684_exit);

MODULE_AUTHOR("Marcell GAL");
MODULE_DESCRIPTION("RFC2684 bridged protocols over ATM/AAL5");
MODULE_LICENSE("GPL");