[PATCH] reiserfs: handle trans_id overflow

[linux-2.6/mini2440.git] / net / atm / clip.c

/* net/atm/clip.c - RFC1577 Classical IP over ATM */

/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */


#include <linux/config.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/kernel.h> /* for UINT_MAX */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/timer.h>
#include <linux/if_arp.h> /* for some manifest constants */
#include <linux/notifier.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/atmclip.h>
#include <linux/atmarp.h>
#include <linux/capability.h>
#include <linux/ip.h> /* for net/route.h */
#include <linux/in.h> /* for struct sockaddr_in */
#include <linux/if.h> /* for IFF_UP */
#include <linux/inetdevice.h>
#include <linux/bitops.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/rcupdate.h>
#include <linux/jhash.h>
#include <net/route.h> /* for struct rtable and routing */
#include <net/icmp.h> /* icmp_send */
#include <asm/param.h> /* for HZ */
#include <asm/byteorder.h> /* for htons etc. */
#include <asm/system.h> /* save/restore_flags */
#include <asm/uaccess.h>
#include <asm/atomic.h>

#include "common.h"
#include "resources.h"
#include "ipcommon.h"
#include <net/atmclip.h>


#if 0
#define DPRINTK(format,args...) printk(format,##args)
#else
#define DPRINTK(format,args...)
#endif


static struct net_device *clip_devs;
static struct atm_vcc *atmarpd;
static struct neigh_table clip_tbl;
static struct timer_list idle_timer;
static int start_timer = 1;


static int to_atmarpd(enum atmarp_ctrl_type type,int itf,unsigned long ip)
{
        struct sock *sk;
        struct atmarp_ctrl *ctrl;
        struct sk_buff *skb;

        DPRINTK("to_atmarpd(%d)\n",type);
        if (!atmarpd) return -EUNATCH;
        skb = alloc_skb(sizeof(struct atmarp_ctrl),GFP_ATOMIC);
        if (!skb) return -ENOMEM;
        ctrl = (struct atmarp_ctrl *) skb_put(skb,sizeof(struct atmarp_ctrl));
        ctrl->type = type;
        ctrl->itf_num = itf;
        ctrl->ip = ip;
        atm_force_charge(atmarpd,skb->truesize);

        sk = sk_atm(atmarpd);
        skb_queue_tail(&sk->sk_receive_queue, skb);
        sk->sk_data_ready(sk, skb->len);
        return 0;
}


static void link_vcc(struct clip_vcc *clip_vcc,struct atmarp_entry *entry)
{
        DPRINTK("link_vcc %p to entry %p (neigh %p)\n",clip_vcc,entry,
            entry->neigh);
        clip_vcc->entry = entry;
        clip_vcc->xoff = 0; /* @@@ may overrun buffer by one packet */
        clip_vcc->next = entry->vccs;
        entry->vccs = clip_vcc;
        entry->neigh->used = jiffies;
}


static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
{
        struct atmarp_entry *entry = clip_vcc->entry;
        struct clip_vcc **walk;

        if (!entry) {
                printk(KERN_CRIT "!clip_vcc->entry (clip_vcc %p)\n",clip_vcc);
                return;
        }
        spin_lock_bh(&entry->neigh->dev->xmit_lock);    /* block clip_start_xmit() */
        entry->neigh->used = jiffies;
        for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
                if (*walk == clip_vcc) {
                        int error;

                        *walk = clip_vcc->next; /* atomic */
                        clip_vcc->entry = NULL;
                        if (clip_vcc->xoff)
                                netif_wake_queue(entry->neigh->dev);
                        if (entry->vccs)
                                goto out;
                        entry->expires = jiffies-1;
                                /* force resolution or expiration */
                        error = neigh_update(entry->neigh, NULL, NUD_NONE,
                                             NEIGH_UPDATE_F_ADMIN);
                        if (error)
                                printk(KERN_CRIT "unlink_clip_vcc: "
                                    "neigh_update failed with %d\n",error);
                        goto out;
                }
        printk(KERN_CRIT "ATMARP: unlink_clip_vcc failed (entry %p, vcc "
          "0x%p)\n",entry,clip_vcc);
out:
        spin_unlock_bh(&entry->neigh->dev->xmit_lock);
}

/* The neighbour entry n->lock is held. */
static int neigh_check_cb(struct neighbour *n)
{
        struct atmarp_entry *entry = NEIGH2ENTRY(n);
        struct clip_vcc *cv;

        for (cv = entry->vccs; cv; cv = cv->next) {
                unsigned long exp = cv->last_use + cv->idle_timeout;

                if (cv->idle_timeout && time_after(jiffies, exp)) {
                        DPRINTK("releasing vcc %p->%p of entry %p\n",
                                cv, cv->vcc, entry);
                        vcc_release_async(cv->vcc, -ETIMEDOUT);
                }
        }

        if (entry->vccs || time_before(jiffies, entry->expires))
                return 0;

        if (atomic_read(&n->refcnt) > 1) {
                struct sk_buff *skb;

                DPRINTK("destruction postponed with ref %d\n",
                        atomic_read(&n->refcnt));

                while ((skb = skb_dequeue(&n->arp_queue)) != NULL) 
                        dev_kfree_skb(skb);

                return 0;
        }

        DPRINTK("expired neigh %p\n",n);
        return 1;
}

static void idle_timer_check(unsigned long dummy)
{
        write_lock(&clip_tbl.lock);
        __neigh_for_each_release(&clip_tbl, neigh_check_cb);
        mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
        write_unlock(&clip_tbl.lock);
}

static int clip_arp_rcv(struct sk_buff *skb)
{
        struct atm_vcc *vcc;

        DPRINTK("clip_arp_rcv\n");
        vcc = ATM_SKB(skb)->vcc;
        if (!vcc || !atm_charge(vcc,skb->truesize)) {
                dev_kfree_skb_any(skb);
                return 0;
        }
        DPRINTK("pushing to %p\n",vcc);
        DPRINTK("using %p\n",CLIP_VCC(vcc)->old_push);
        CLIP_VCC(vcc)->old_push(vcc,skb);
        return 0;
}

static const unsigned char llc_oui[] = {
        0xaa,   /* DSAP: non-ISO */
        0xaa,   /* SSAP: non-ISO */
        0x03,   /* Ctrl: Unnumbered Information Command PDU */
        0x00,   /* OUI: EtherType */
        0x00,
        0x00 };

static void clip_push(struct atm_vcc *vcc,struct sk_buff *skb)
{
        struct clip_vcc *clip_vcc = CLIP_VCC(vcc);

        DPRINTK("clip push\n");
        if (!skb) {
                DPRINTK("removing VCC %p\n",clip_vcc);
                if (clip_vcc->entry) unlink_clip_vcc(clip_vcc);
                clip_vcc->old_push(vcc,NULL); /* pass on the bad news */
                kfree(clip_vcc);
                return;
        }
        atm_return(vcc,skb->truesize);
        skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
                /* clip_vcc->entry == NULL if we don't have an IP address yet */
        if (!skb->dev) {
                dev_kfree_skb_any(skb);
                return;
        }
        ATM_SKB(skb)->vcc = vcc;
        skb->mac.raw = skb->data;
        if (!clip_vcc->encap || skb->len < RFC1483LLC_LEN || memcmp(skb->data,
            llc_oui,sizeof(llc_oui))) skb->protocol = htons(ETH_P_IP);
        else {
                skb->protocol = ((u16 *) skb->data)[3];
                skb_pull(skb,RFC1483LLC_LEN);
                if (skb->protocol == htons(ETH_P_ARP)) {
                        PRIV(skb->dev)->stats.rx_packets++;
                        PRIV(skb->dev)->stats.rx_bytes += skb->len;
                        clip_arp_rcv(skb);
                        return;
                }
        }
        clip_vcc->last_use = jiffies;
        PRIV(skb->dev)->stats.rx_packets++;
        PRIV(skb->dev)->stats.rx_bytes += skb->len;
        memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
        netif_rx(skb);
}


/*
 * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
 * clip_pop is atomic with respect to the critical section in clip_start_xmit.
 */


static void clip_pop(struct atm_vcc *vcc,struct sk_buff *skb)
{
        struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
        struct net_device *dev = skb->dev;
        int old;
        unsigned long flags;

        DPRINTK("clip_pop(vcc %p)\n",vcc);
        clip_vcc->old_pop(vcc,skb);
        /* skb->dev == NULL in outbound ARP packets */
        if (!dev) return;
        spin_lock_irqsave(&PRIV(dev)->xoff_lock,flags);
        if (atm_may_send(vcc,0)) {
                old = xchg(&clip_vcc->xoff,0);
                if (old) netif_wake_queue(dev);
        }
        spin_unlock_irqrestore(&PRIV(dev)->xoff_lock,flags);
}


static void clip_neigh_destroy(struct neighbour *neigh)
{
        DPRINTK("clip_neigh_destroy (neigh %p)\n",neigh);
        if (NEIGH2ENTRY(neigh)->vccs)
                printk(KERN_CRIT "clip_neigh_destroy: vccs != NULL !!!\n");
        NEIGH2ENTRY(neigh)->vccs = (void *) 0xdeadbeef;
}


static void clip_neigh_solicit(struct neighbour *neigh,struct sk_buff *skb)
{
        DPRINTK("clip_neigh_solicit (neigh %p, skb %p)\n",neigh,skb);
        to_atmarpd(act_need,PRIV(neigh->dev)->number,NEIGH2ENTRY(neigh)->ip);
}


static void clip_neigh_error(struct neighbour *neigh,struct sk_buff *skb)
{
#ifndef CONFIG_ATM_CLIP_NO_ICMP
        icmp_send(skb,ICMP_DEST_UNREACH,ICMP_HOST_UNREACH,0);
#endif
        kfree_skb(skb);
}


static struct neigh_ops clip_neigh_ops = {
        .family =               AF_INET,
        .solicit =              clip_neigh_solicit,
        .error_report =         clip_neigh_error,
        .output =               dev_queue_xmit,
        .connected_output =     dev_queue_xmit,
        .hh_output =            dev_queue_xmit,
        .queue_xmit =           dev_queue_xmit,
};


static int clip_constructor(struct neighbour *neigh)
{
        struct atmarp_entry *entry = NEIGH2ENTRY(neigh);
        struct net_device *dev = neigh->dev;
        struct in_device *in_dev;
        struct neigh_parms *parms;

        DPRINTK("clip_constructor (neigh %p, entry %p)\n",neigh,entry);
        neigh->type = inet_addr_type(entry->ip);
        if (neigh->type != RTN_UNICAST) return -EINVAL;

        rcu_read_lock();
        in_dev = __in_dev_get_rcu(dev);
        if (!in_dev) {
                rcu_read_unlock();
                return -EINVAL;
        }

        parms = in_dev->arp_parms;
        __neigh_parms_put(neigh->parms);
        neigh->parms = neigh_parms_clone(parms);
        rcu_read_unlock();

        neigh->ops = &clip_neigh_ops;
        neigh->output = neigh->nud_state & NUD_VALID ?
            neigh->ops->connected_output : neigh->ops->output;
        entry->neigh = neigh;
        entry->vccs = NULL;
        entry->expires = jiffies-1;
        return 0;
}

static u32 clip_hash(const void *pkey, const struct net_device *dev)
{
        return jhash_2words(*(u32 *)pkey, dev->ifindex, clip_tbl.hash_rnd);
}

static struct neigh_table clip_tbl = {
        .family         = AF_INET,
        .entry_size     = sizeof(struct neighbour)+sizeof(struct atmarp_entry),
        .key_len        = 4,
        .hash           = clip_hash,
        .constructor    = clip_constructor,
        .id             = "clip_arp_cache",

        /* parameters are copied from ARP ... */
        .parms = {
                .tbl                    = &clip_tbl,
                .neigh_destructor       = clip_neigh_destroy,
                .base_reachable_time    = 30 * HZ,
                .retrans_time           = 1 * HZ,
                .gc_staletime           = 60 * HZ,
                .reachable_time         = 30 * HZ,
                .delay_probe_time       = 5 * HZ,
                .queue_len              = 3,
                .ucast_probes           = 3,
                .mcast_probes           = 3,
                .anycast_delay          = 1 * HZ,
                .proxy_delay            = (8 * HZ) / 10,
                .proxy_qlen             = 64,
                .locktime               = 1 * HZ,
        },
        .gc_interval    = 30 * HZ,
        .gc_thresh1     = 128,
        .gc_thresh2     = 512,
        .gc_thresh3     = 1024,
};


/* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */

/*
 * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
 * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
 * don't increment the usage count. This is used to create entries in
 * clip_setentry.
 */


static int clip_encap(struct atm_vcc *vcc,int mode)
{
        CLIP_VCC(vcc)->encap = mode;
        return 0;
}


static int clip_start_xmit(struct sk_buff *skb,struct net_device *dev)
{
        struct clip_priv *clip_priv = PRIV(dev);
        struct atmarp_entry *entry;
        struct atm_vcc *vcc;
        int old;
        unsigned long flags;

        DPRINTK("clip_start_xmit (skb %p)\n",skb);
        if (!skb->dst) {
                printk(KERN_ERR "clip_start_xmit: skb->dst == NULL\n");
                dev_kfree_skb(skb);
                clip_priv->stats.tx_dropped++;
                return 0;
        }
        if (!skb->dst->neighbour) {
#if 0
                skb->dst->neighbour = clip_find_neighbour(skb->dst,1);
                if (!skb->dst->neighbour) {
                        dev_kfree_skb(skb); /* lost that one */
                        clip_priv->stats.tx_dropped++;
                        return 0;
                }
#endif
                printk(KERN_ERR "clip_start_xmit: NO NEIGHBOUR !\n");
                dev_kfree_skb(skb);
                clip_priv->stats.tx_dropped++;
                return 0;
        }
        entry = NEIGH2ENTRY(skb->dst->neighbour);
        if (!entry->vccs) {
                if (time_after(jiffies, entry->expires)) {
                        /* should be resolved */
                        entry->expires = jiffies+ATMARP_RETRY_DELAY*HZ;
                        to_atmarpd(act_need,PRIV(dev)->number,entry->ip);
                }
                if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
                        skb_queue_tail(&entry->neigh->arp_queue,skb);
                else {
                        dev_kfree_skb(skb);
                        clip_priv->stats.tx_dropped++;
                }
                return 0;
        }
        DPRINTK("neigh %p, vccs %p\n",entry,entry->vccs);
        ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
        DPRINTK("using neighbour %p, vcc %p\n",skb->dst->neighbour,vcc);
        if (entry->vccs->encap) {
                void *here;

                here = skb_push(skb,RFC1483LLC_LEN);
                memcpy(here,llc_oui,sizeof(llc_oui));
                ((u16 *) here)[3] = skb->protocol;
        }
        atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
        ATM_SKB(skb)->atm_options = vcc->atm_options;
        entry->vccs->last_use = jiffies;
        DPRINTK("atm_skb(%p)->vcc(%p)->dev(%p)\n",skb,vcc,vcc->dev);
        old = xchg(&entry->vccs->xoff,1); /* assume XOFF ... */
        if (old) {
                printk(KERN_WARNING "clip_start_xmit: XOFF->XOFF transition\n");
                return 0;
        }
        clip_priv->stats.tx_packets++;
        clip_priv->stats.tx_bytes += skb->len;
        (void) vcc->send(vcc,skb);
        if (atm_may_send(vcc,0)) {
                entry->vccs->xoff = 0;
                return 0;
        }
        spin_lock_irqsave(&clip_priv->xoff_lock,flags);
        netif_stop_queue(dev); /* XOFF -> throttle immediately */
        barrier();
        if (!entry->vccs->xoff)
                netif_start_queue(dev);
                /* Oh, we just raced with clip_pop. netif_start_queue should be
                   good enough, because nothing should really be asleep because
                   of the brief netif_stop_queue. If this isn't true or if it
                   changes, use netif_wake_queue instead. */
        spin_unlock_irqrestore(&clip_priv->xoff_lock,flags);
        return 0;
}


static struct net_device_stats *clip_get_stats(struct net_device *dev)
{
        return &PRIV(dev)->stats;
}


static int clip_mkip(struct atm_vcc *vcc,int timeout)
{
        struct clip_vcc *clip_vcc;
        struct sk_buff_head copy;
        struct sk_buff *skb;

        if (!vcc->push) return -EBADFD;
        clip_vcc = kmalloc(sizeof(struct clip_vcc),GFP_KERNEL);
        if (!clip_vcc) return -ENOMEM;
        DPRINTK("mkip clip_vcc %p vcc %p\n",clip_vcc,vcc);
        clip_vcc->vcc = vcc;
        vcc->user_back = clip_vcc;
        set_bit(ATM_VF_IS_CLIP, &vcc->flags);
        clip_vcc->entry = NULL;
        clip_vcc->xoff = 0;
        clip_vcc->encap = 1;
        clip_vcc->last_use = jiffies;
        clip_vcc->idle_timeout = timeout*HZ;
        clip_vcc->old_push = vcc->push;
        clip_vcc->old_pop = vcc->pop;
        vcc->push = clip_push;
        vcc->pop = clip_pop;
        skb_queue_head_init(&copy);
        skb_migrate(&sk_atm(vcc)->sk_receive_queue, &copy);
        /* re-process everything received between connection setup and MKIP */
        while ((skb = skb_dequeue(&copy)) != NULL)
                if (!clip_devs) {
                        atm_return(vcc,skb->truesize);
                        kfree_skb(skb);
                }
                else {
                        unsigned int len = skb->len;

                        clip_push(vcc,skb);
                        PRIV(skb->dev)->stats.rx_packets--;
                        PRIV(skb->dev)->stats.rx_bytes -= len;
                }
        return 0;
}


static int clip_setentry(struct atm_vcc *vcc,u32 ip)
{
        struct neighbour *neigh;
        struct atmarp_entry *entry;
        int error;
        struct clip_vcc *clip_vcc;
        struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, .tos = 1 } } };
        struct rtable *rt;

        if (vcc->push != clip_push) {
                printk(KERN_WARNING "clip_setentry: non-CLIP VCC\n");
                return -EBADF;
        }
        clip_vcc = CLIP_VCC(vcc);
        if (!ip) {
                if (!clip_vcc->entry) {
                        printk(KERN_ERR "hiding hidden ATMARP entry\n");
                        return 0;
                }
                DPRINTK("setentry: remove\n");
                unlink_clip_vcc(clip_vcc);
                return 0;
        }
        error = ip_route_output_key(&rt,&fl);
        if (error) return error;
        neigh = __neigh_lookup(&clip_tbl,&ip,rt->u.dst.dev,1);
        ip_rt_put(rt);
        if (!neigh)
                return -ENOMEM;
        entry = NEIGH2ENTRY(neigh);
        if (entry != clip_vcc->entry) {
                if (!clip_vcc->entry) DPRINTK("setentry: add\n");
                else {
                        DPRINTK("setentry: update\n");
                        unlink_clip_vcc(clip_vcc);
                }
                link_vcc(clip_vcc,entry);
        }
        error = neigh_update(neigh, llc_oui, NUD_PERMANENT, 
                             NEIGH_UPDATE_F_OVERRIDE|NEIGH_UPDATE_F_ADMIN);
        neigh_release(neigh);
        return error;
}


static void clip_setup(struct net_device *dev)
{
        dev->hard_start_xmit = clip_start_xmit;
        /* sg_xmit ... */
        dev->get_stats = clip_get_stats;
        dev->type = ARPHRD_ATM;
        dev->hard_header_len = RFC1483LLC_LEN;
        dev->mtu = RFC1626_MTU;
        dev->tx_queue_len = 100; /* "normal" queue (packets) */
            /* When using a "real" qdisc, the qdisc determines the queue */
            /* length. tx_queue_len is only used for the default case, */
            /* without any more elaborate queuing. 100 is a reasonable */
            /* compromise between decent burst-tolerance and protection */
            /* against memory hogs. */
}


static int clip_create(int number)
{
        struct net_device *dev;
        struct clip_priv *clip_priv;
        int error;

        if (number != -1) {
                for (dev = clip_devs; dev; dev = PRIV(dev)->next)
                        if (PRIV(dev)->number == number) return -EEXIST;
        }
        else {
                number = 0;
                for (dev = clip_devs; dev; dev = PRIV(dev)->next)
                        if (PRIV(dev)->number >= number)
                                number = PRIV(dev)->number+1;
        }
        dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
        if (!dev)
                return -ENOMEM;
        clip_priv = PRIV(dev);
        sprintf(dev->name,"atm%d",number);
        spin_lock_init(&clip_priv->xoff_lock);
        clip_priv->number = number;
        error = register_netdev(dev);
        if (error) {
                free_netdev(dev);
                return error;
        }
        clip_priv->next = clip_devs;
        clip_devs = dev;
        DPRINTK("registered (net:%s)\n",dev->name);
        return number;
}


static int clip_device_event(struct notifier_block *this,unsigned long event,
    void *dev)
{
        /* ignore non-CLIP devices */
        if (((struct net_device *) dev)->type != ARPHRD_ATM ||
            ((struct net_device *) dev)->hard_start_xmit != clip_start_xmit)
                return NOTIFY_DONE;
        switch (event) {
                case NETDEV_UP:
                        DPRINTK("clip_device_event NETDEV_UP\n");
                        (void) to_atmarpd(act_up,PRIV(dev)->number,0);
                        break;
                case NETDEV_GOING_DOWN:
                        DPRINTK("clip_device_event NETDEV_DOWN\n");
                        (void) to_atmarpd(act_down,PRIV(dev)->number,0);
                        break;
                case NETDEV_CHANGE:
                case NETDEV_CHANGEMTU:
                        DPRINTK("clip_device_event NETDEV_CHANGE*\n");
                        (void) to_atmarpd(act_change,PRIV(dev)->number,0);
                        break;
                case NETDEV_REBOOT:
                case NETDEV_REGISTER:
                case NETDEV_DOWN:
                        DPRINTK("clip_device_event %ld\n",event);
                        /* ignore */
                        break;
                default:
                        printk(KERN_WARNING "clip_device_event: unknown event "
                            "%ld\n",event);
                        break;
        }
        return NOTIFY_DONE;
}


static int clip_inet_event(struct notifier_block *this,unsigned long event,
    void *ifa)
{
        struct in_device *in_dev;

        in_dev = ((struct in_ifaddr *) ifa)->ifa_dev;
        if (!in_dev || !in_dev->dev) {
                printk(KERN_WARNING "clip_inet_event: no device\n");
                return NOTIFY_DONE;
        }
        /*
         * Transitions are of the down-change-up type, so it's sufficient to
         * handle the change on up.
         */
        if (event != NETDEV_UP) return NOTIFY_DONE;
        return clip_device_event(this,NETDEV_CHANGE,in_dev->dev);
}


static struct notifier_block clip_dev_notifier = {
        clip_device_event,
        NULL,
        0
};



static struct notifier_block clip_inet_notifier = {
        clip_inet_event,
        NULL,
        0
};



static void atmarpd_close(struct atm_vcc *vcc)
{
        DPRINTK("atmarpd_close\n");
        atmarpd = NULL; /* assumed to be atomic */
        barrier();
        unregister_inetaddr_notifier(&clip_inet_notifier);
        unregister_netdevice_notifier(&clip_dev_notifier);
        if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
                printk(KERN_ERR "atmarpd_close: closing with requests "
                    "pending\n");
        skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
        DPRINTK("(done)\n");
        module_put(THIS_MODULE);
}


static struct atmdev_ops atmarpd_dev_ops = {
        .close = atmarpd_close
};


static struct atm_dev atmarpd_dev = {
        .ops =                  &atmarpd_dev_ops,
        .type =                 "arpd",
        .number =               999,
        .lock =                 SPIN_LOCK_UNLOCKED
};


static int atm_init_atmarp(struct atm_vcc *vcc)
{
        if (atmarpd) return -EADDRINUSE;
        if (start_timer) {
                start_timer = 0;
                init_timer(&idle_timer);
                idle_timer.expires = jiffies+CLIP_CHECK_INTERVAL*HZ;
                idle_timer.function = idle_timer_check;
                add_timer(&idle_timer);
        }
        atmarpd = vcc;
        set_bit(ATM_VF_META,&vcc->flags);
        set_bit(ATM_VF_READY,&vcc->flags);
            /* allow replies and avoid getting closed if signaling dies */
        vcc->dev = &atmarpd_dev;
        vcc_insert_socket(sk_atm(vcc));
        vcc->push = NULL;
        vcc->pop = NULL; /* crash */
        vcc->push_oam = NULL; /* crash */
        if (register_netdevice_notifier(&clip_dev_notifier))
                printk(KERN_ERR "register_netdevice_notifier failed\n");
        if (register_inetaddr_notifier(&clip_inet_notifier))
                printk(KERN_ERR "register_inetaddr_notifier failed\n");
        return 0;
}

static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
        struct atm_vcc *vcc = ATM_SD(sock);
        int err = 0;

        switch (cmd) {
                case SIOCMKCLIP:
                case ATMARPD_CTRL:
                case ATMARP_MKIP:
                case ATMARP_SETENTRY:
                case ATMARP_ENCAP:
                        if (!capable(CAP_NET_ADMIN))
                                return -EPERM;
                        break;
                default:
                        return -ENOIOCTLCMD;
        }

        switch (cmd) {
                case SIOCMKCLIP:
                        err = clip_create(arg);
                        break;
                case ATMARPD_CTRL:
                        err = atm_init_atmarp(vcc);
                        if (!err) {
                                sock->state = SS_CONNECTED;
                                __module_get(THIS_MODULE);
                        }
                        break;
                case ATMARP_MKIP:
                        err = clip_mkip(vcc ,arg);
                        break;
                case ATMARP_SETENTRY:
                        err = clip_setentry(vcc, arg);
                        break;
                case ATMARP_ENCAP:
                        err = clip_encap(vcc, arg);
                        break;
        }
        return err;
}

static struct atm_ioctl clip_ioctl_ops = {
        .owner  = THIS_MODULE,
        .ioctl  = clip_ioctl,
};

#ifdef CONFIG_PROC_FS

static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
{
        static int code[] = { 1,2,10,6,1,0 };
        static int e164[] = { 1,8,4,6,1,0 };

        if (*addr->sas_addr.pub) {
                seq_printf(seq, "%s", addr->sas_addr.pub);
                if (*addr->sas_addr.prv)
                        seq_putc(seq, '+');
        } else if (!*addr->sas_addr.prv) {
                seq_printf(seq, "%s", "(none)");
                return;
        }
        if (*addr->sas_addr.prv) {
                unsigned char *prv = addr->sas_addr.prv;
                int *fields;
                int i, j;

                fields = *prv == ATM_AFI_E164 ? e164 : code;
                for (i = 0; fields[i]; i++) {
                        for (j = fields[i]; j; j--)
                                seq_printf(seq, "%02X", *prv++);
                        if (fields[i+1])
                                seq_putc(seq, '.');
                }
        }
}

/* This means the neighbour entry has no attached VCC objects. */
#define SEQ_NO_VCC_TOKEN        ((void *) 2)

static void atmarp_info(struct seq_file *seq, struct net_device *dev,
                        struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
{
        unsigned long exp;
        char buf[17];
        int svc, llc, off;

        svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
               (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));

        llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
               clip_vcc->encap);

        if (clip_vcc == SEQ_NO_VCC_TOKEN)
                exp = entry->neigh->used;
        else
                exp = clip_vcc->last_use;

        exp = (jiffies - exp) / HZ;

        seq_printf(seq, "%-6s%-4s%-4s%5ld ",
                   dev->name,
                   svc ? "SVC" : "PVC",
                   llc ? "LLC" : "NULL",
                   exp);

        off = scnprintf(buf, sizeof(buf) - 1, "%d.%d.%d.%d",
                        NIPQUAD(entry->ip));
        while (off < 16)
                buf[off++] = ' ';
        buf[off] = '\0';
        seq_printf(seq, "%s", buf);

        if (clip_vcc == SEQ_NO_VCC_TOKEN) {
                if (time_before(jiffies, entry->expires))
                        seq_printf(seq, "(resolving)\n");
                else
                        seq_printf(seq, "(expired, ref %d)\n",
                                   atomic_read(&entry->neigh->refcnt));
        } else if (!svc) {
                seq_printf(seq, "%d.%d.%d\n",
                           clip_vcc->vcc->dev->number,
                           clip_vcc->vcc->vpi,
                           clip_vcc->vcc->vci);
        } else {
                svc_addr(seq, &clip_vcc->vcc->remote);
                seq_putc(seq, '\n');
        }
}

struct clip_seq_state {
        /* This member must be first. */
        struct neigh_seq_state ns;

        /* Local to clip specific iteration. */
        struct clip_vcc *vcc;
};

static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
                                          struct clip_vcc *curr)
{
        if (!curr) {
                curr = e->vccs;
                if (!curr)
                        return SEQ_NO_VCC_TOKEN;
                return curr;
        }
        if (curr == SEQ_NO_VCC_TOKEN)
                return NULL;

        curr = curr->next;

        return curr;
}

static void *clip_seq_vcc_walk(struct clip_seq_state *state,
                               struct atmarp_entry *e, loff_t *pos)
{
        struct clip_vcc *vcc = state->vcc;

        vcc = clip_seq_next_vcc(e, vcc);
        if (vcc && pos != NULL) {
                while (*pos) {
                        vcc = clip_seq_next_vcc(e, vcc);
                        if (!vcc)
                                break;
                        --(*pos);
                }
        }
        state->vcc = vcc;

        return vcc;
}
  
static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
                               struct neighbour *n, loff_t *pos)
{
        struct clip_seq_state *state = (struct clip_seq_state *) _state;

        return clip_seq_vcc_walk(state, NEIGH2ENTRY(n), pos);
}

static void *clip_seq_start(struct seq_file *seq, loff_t *pos)
{
        return neigh_seq_start(seq, pos, &clip_tbl, NEIGH_SEQ_NEIGH_ONLY);
}

static int clip_seq_show(struct seq_file *seq, void *v)
{
        static char atm_arp_banner[] = 
                "IPitf TypeEncp Idle IP address      ATM address\n";

        if (v == SEQ_START_TOKEN) {
                seq_puts(seq, atm_arp_banner);
        } else {
                struct clip_seq_state *state = seq->private;
                struct neighbour *n = v;
                struct clip_vcc *vcc = state->vcc;

                atmarp_info(seq, n->dev, NEIGH2ENTRY(n), vcc);
        }
        return 0;
}

static struct seq_operations arp_seq_ops = {
        .start  = clip_seq_start,
        .next   = neigh_seq_next,
        .stop   = neigh_seq_stop,
        .show   = clip_seq_show,
};

static int arp_seq_open(struct inode *inode, struct file *file)
{
        struct clip_seq_state *state;
        struct seq_file *seq;
        int rc = -EAGAIN;

        state = kmalloc(sizeof(*state), GFP_KERNEL);
        if (!state) {
                rc = -ENOMEM;
                goto out_kfree;
        }
        memset(state, 0, sizeof(*state));
        state->ns.neigh_sub_iter = clip_seq_sub_iter;

        rc = seq_open(file, &arp_seq_ops);
        if (rc)
                goto out_kfree;

        seq = file->private_data;
        seq->private = state;
out:
        return rc;

out_kfree:
        kfree(state);
        goto out;
}

static struct file_operations arp_seq_fops = {
        .open           = arp_seq_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release_private,
        .owner          = THIS_MODULE
};
#endif

static int __init atm_clip_init(void)
{
        neigh_table_init(&clip_tbl);

        clip_tbl_hook = &clip_tbl;
        register_atm_ioctl(&clip_ioctl_ops);

#ifdef CONFIG_PROC_FS
{
        struct proc_dir_entry *p;

        p = create_proc_entry("arp", S_IRUGO, atm_proc_root);
        if (p)
                p->proc_fops = &arp_seq_fops;
}
#endif

        return 0;
}

static void __exit atm_clip_exit(void)
{
        struct net_device *dev, *next;

        remove_proc_entry("arp", atm_proc_root);

        deregister_atm_ioctl(&clip_ioctl_ops);

        /* First, stop the idle timer, so it stops banging
         * on the table.
         */
        if (start_timer == 0)
                del_timer(&idle_timer);

        /* Next, purge the table, so that the device
         * unregister loop below does not hang due to
         * device references remaining in the table.
         */
        neigh_ifdown(&clip_tbl, NULL);

        dev = clip_devs;
        while (dev) {
                next = PRIV(dev)->next;
                unregister_netdev(dev);
                free_netdev(dev);
                dev = next;
        }

        /* Now it is safe to fully shutdown whole table. */
        neigh_table_clear(&clip_tbl);

        clip_tbl_hook = NULL;
}

module_init(atm_clip_init);
module_exit(atm_clip_exit);

MODULE_LICENSE("GPL");