networking: make skb_put & friends return void pointers

[mirror_ubuntu-artful-kernel.git] / drivers / isdn / capi / capi.c

/* $Id: capi.c,v 1.1.2.7 2004/04/28 09:48:59 armin Exp $
 *
 * CAPI 2.0 Interface for Linux
 *
 * Copyright 1996 by Carsten Paeth <calle@calle.de>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/fs.h>
#include <linux/signal.h>
#include <linux/mutex.h>
#include <linux/mm.h>
#include <linux/timer.h>
#include <linux/wait.h>
#include <linux/tty.h>
#include <linux/netdevice.h>
#include <linux/ppp_defs.h>
#include <linux/ppp-ioctl.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/capi.h>
#include <linux/kernelcapi.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/moduleparam.h>
#include <linux/isdn/capiutil.h>
#include <linux/isdn/capicmd.h>

MODULE_DESCRIPTION("CAPI4Linux: Userspace /dev/capi20 interface");
MODULE_AUTHOR("Carsten Paeth");
MODULE_LICENSE("GPL");

/* -------- driver information -------------------------------------- */

static DEFINE_MUTEX(capi_mutex);
static struct class *capi_class;
static int capi_major = 68;             /* allocated */

module_param_named(major, capi_major, uint, 0);

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
#define CAPINC_NR_PORTS         32
#define CAPINC_MAX_PORTS        256

static int capi_ttyminors = CAPINC_NR_PORTS;

module_param_named(ttyminors, capi_ttyminors, uint, 0);
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

/* -------- defines ------------------------------------------------- */

#define CAPINC_MAX_RECVQUEUE    10
#define CAPINC_MAX_SENDQUEUE    10
#define CAPI_MAX_BLKSIZE        2048

/* -------- data structures ----------------------------------------- */

struct capidev;
struct capincci;
struct capiminor;

struct ackqueue_entry {
        struct list_head        list;
        u16                     datahandle;
};

struct capiminor {
        unsigned int      minor;

        struct capi20_appl      *ap;
        u32                     ncci;
        atomic_t                datahandle;
        atomic_t                msgid;

        struct tty_port port;
        int                ttyinstop;
        int                ttyoutstop;

        struct sk_buff_head     inqueue;

        struct sk_buff_head     outqueue;
        int                     outbytes;
        struct sk_buff          *outskb;
        spinlock_t              outlock;

        /* transmit path */
        struct list_head ackqueue;
        int nack;
        spinlock_t ackqlock;
};

struct capincci {
        struct list_head list;
        u32              ncci;
        struct capidev  *cdev;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
        struct capiminor *minorp;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
};

struct capidev {
        struct list_head list;
        struct capi20_appl ap;
        u16             errcode;
        unsigned        userflags;

        struct sk_buff_head recvqueue;
        wait_queue_head_t recvwait;

        struct list_head nccis;

        struct mutex lock;
};

/* -------- global variables ---------------------------------------- */

static DEFINE_MUTEX(capidev_list_lock);
static LIST_HEAD(capidev_list);

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE

static DEFINE_SPINLOCK(capiminors_lock);
static struct capiminor **capiminors;

static struct tty_driver *capinc_tty_driver;

/* -------- datahandles --------------------------------------------- */

static int capiminor_add_ack(struct capiminor *mp, u16 datahandle)
{
        struct ackqueue_entry *n;

        n = kmalloc(sizeof(*n), GFP_ATOMIC);
        if (unlikely(!n)) {
                printk(KERN_ERR "capi: alloc datahandle failed\n");
                return -1;
        }
        n->datahandle = datahandle;
        INIT_LIST_HEAD(&n->list);
        spin_lock_bh(&mp->ackqlock);
        list_add_tail(&n->list, &mp->ackqueue);
        mp->nack++;
        spin_unlock_bh(&mp->ackqlock);
        return 0;
}

static int capiminor_del_ack(struct capiminor *mp, u16 datahandle)
{
        struct ackqueue_entry *p, *tmp;

        spin_lock_bh(&mp->ackqlock);
        list_for_each_entry_safe(p, tmp, &mp->ackqueue, list) {
                if (p->datahandle == datahandle) {
                        list_del(&p->list);
                        mp->nack--;
                        spin_unlock_bh(&mp->ackqlock);
                        kfree(p);
                        return 0;
                }
        }
        spin_unlock_bh(&mp->ackqlock);
        return -1;
}

static void capiminor_del_all_ack(struct capiminor *mp)
{
        struct ackqueue_entry *p, *tmp;

        list_for_each_entry_safe(p, tmp, &mp->ackqueue, list) {
                list_del(&p->list);
                kfree(p);
                mp->nack--;
        }
}


/* -------- struct capiminor ---------------------------------------- */

static void capiminor_destroy(struct tty_port *port)
{
        struct capiminor *mp = container_of(port, struct capiminor, port);

        kfree_skb(mp->outskb);
        skb_queue_purge(&mp->inqueue);
        skb_queue_purge(&mp->outqueue);
        capiminor_del_all_ack(mp);
        kfree(mp);
}

static const struct tty_port_operations capiminor_port_ops = {
        .destruct = capiminor_destroy,
};

static struct capiminor *capiminor_alloc(struct capi20_appl *ap, u32 ncci)
{
        struct capiminor *mp;
        struct device *dev;
        unsigned int minor;

        mp = kzalloc(sizeof(*mp), GFP_KERNEL);
        if (!mp) {
                printk(KERN_ERR "capi: can't alloc capiminor\n");
                return NULL;
        }

        mp->ap = ap;
        mp->ncci = ncci;
        INIT_LIST_HEAD(&mp->ackqueue);
        spin_lock_init(&mp->ackqlock);

        skb_queue_head_init(&mp->inqueue);
        skb_queue_head_init(&mp->outqueue);
        spin_lock_init(&mp->outlock);

        tty_port_init(&mp->port);
        mp->port.ops = &capiminor_port_ops;

        /* Allocate the least unused minor number. */
        spin_lock(&capiminors_lock);
        for (minor = 0; minor < capi_ttyminors; minor++)
                if (!capiminors[minor]) {
                        capiminors[minor] = mp;
                        break;
                }
        spin_unlock(&capiminors_lock);

        if (minor == capi_ttyminors) {
                printk(KERN_NOTICE "capi: out of minors\n");
                goto err_out1;
        }

        mp->minor = minor;

        dev = tty_port_register_device(&mp->port, capinc_tty_driver, minor,
                        NULL);
        if (IS_ERR(dev))
                goto err_out2;

        return mp;

err_out2:
        spin_lock(&capiminors_lock);
        capiminors[minor] = NULL;
        spin_unlock(&capiminors_lock);

err_out1:
        tty_port_put(&mp->port);
        return NULL;
}

static struct capiminor *capiminor_get(unsigned int minor)
{
        struct capiminor *mp;

        spin_lock(&capiminors_lock);
        mp = capiminors[minor];
        if (mp)
                tty_port_get(&mp->port);
        spin_unlock(&capiminors_lock);

        return mp;
}

static inline void capiminor_put(struct capiminor *mp)
{
        tty_port_put(&mp->port);
}

static void capiminor_free(struct capiminor *mp)
{
        tty_unregister_device(capinc_tty_driver, mp->minor);

        spin_lock(&capiminors_lock);
        capiminors[mp->minor] = NULL;
        spin_unlock(&capiminors_lock);

        capiminor_put(mp);
}

/* -------- struct capincci ----------------------------------------- */

static void capincci_alloc_minor(struct capidev *cdev, struct capincci *np)
{
        if (cdev->userflags & CAPIFLAG_HIGHJACKING)
                np->minorp = capiminor_alloc(&cdev->ap, np->ncci);
}

static void capincci_free_minor(struct capincci *np)
{
        struct capiminor *mp = np->minorp;
        struct tty_struct *tty;

        if (mp) {
                tty = tty_port_tty_get(&mp->port);
                if (tty) {
                        tty_vhangup(tty);
                        tty_kref_put(tty);
                }

                capiminor_free(mp);
        }
}

static inline unsigned int capincci_minor_opencount(struct capincci *np)
{
        struct capiminor *mp = np->minorp;
        unsigned int count = 0;
        struct tty_struct *tty;

        if (mp) {
                tty = tty_port_tty_get(&mp->port);
                if (tty) {
                        count = tty->count;
                        tty_kref_put(tty);
                }
        }
        return count;
}

#else /* !CONFIG_ISDN_CAPI_MIDDLEWARE */

static inline void
capincci_alloc_minor(struct capidev *cdev, struct capincci *np) { }
static inline void capincci_free_minor(struct capincci *np) { }

#endif /* !CONFIG_ISDN_CAPI_MIDDLEWARE */

static struct capincci *capincci_alloc(struct capidev *cdev, u32 ncci)
{
        struct capincci *np;

        np = kzalloc(sizeof(*np), GFP_KERNEL);
        if (!np)
                return NULL;
        np->ncci = ncci;
        np->cdev = cdev;

        capincci_alloc_minor(cdev, np);

        list_add_tail(&np->list, &cdev->nccis);

        return np;
}

static void capincci_free(struct capidev *cdev, u32 ncci)
{
        struct capincci *np, *tmp;

        list_for_each_entry_safe(np, tmp, &cdev->nccis, list)
                if (ncci == 0xffffffff || np->ncci == ncci) {
                        capincci_free_minor(np);
                        list_del(&np->list);
                        kfree(np);
                }
}

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
static struct capincci *capincci_find(struct capidev *cdev, u32 ncci)
{
        struct capincci *np;

        list_for_each_entry(np, &cdev->nccis, list)
                if (np->ncci == ncci)
                        return np;
        return NULL;
}

/* -------- handle data queue --------------------------------------- */

static struct sk_buff *
gen_data_b3_resp_for(struct capiminor *mp, struct sk_buff *skb)
{
        struct sk_buff *nskb;
        nskb = alloc_skb(CAPI_DATA_B3_RESP_LEN, GFP_KERNEL);
        if (nskb) {
                u16 datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN + 4 + 4 + 2);
                unsigned char *s = skb_put(nskb, CAPI_DATA_B3_RESP_LEN);
                capimsg_setu16(s, 0, CAPI_DATA_B3_RESP_LEN);
                capimsg_setu16(s, 2, mp->ap->applid);
                capimsg_setu8 (s, 4, CAPI_DATA_B3);
                capimsg_setu8 (s, 5, CAPI_RESP);
                capimsg_setu16(s, 6, atomic_inc_return(&mp->msgid));
                capimsg_setu32(s, 8, mp->ncci);
                capimsg_setu16(s, 12, datahandle);
        }
        return nskb;
}

static int handle_recv_skb(struct capiminor *mp, struct sk_buff *skb)
{
        unsigned int datalen = skb->len - CAPIMSG_LEN(skb->data);
        struct tty_struct *tty;
        struct sk_buff *nskb;
        u16 errcode, datahandle;
        struct tty_ldisc *ld;
        int ret = -1;

        tty = tty_port_tty_get(&mp->port);
        if (!tty) {
                pr_debug("capi: currently no receiver\n");
                return -1;
        }

        ld = tty_ldisc_ref(tty);
        if (!ld) {
                /* fatal error, do not requeue */
                ret = 0;
                kfree_skb(skb);
                goto deref_tty;
        }

        if (ld->ops->receive_buf == NULL) {
                pr_debug("capi: ldisc has no receive_buf function\n");
                /* fatal error, do not requeue */
                goto free_skb;
        }
        if (mp->ttyinstop) {
                pr_debug("capi: recv tty throttled\n");
                goto deref_ldisc;
        }

        if (tty->receive_room < datalen) {
                pr_debug("capi: no room in tty\n");
                goto deref_ldisc;
        }

        nskb = gen_data_b3_resp_for(mp, skb);
        if (!nskb) {
                printk(KERN_ERR "capi: gen_data_b3_resp failed\n");
                goto deref_ldisc;
        }

        datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN + 4);

        errcode = capi20_put_message(mp->ap, nskb);

        if (errcode == CAPI_NOERROR) {
                skb_pull(skb, CAPIMSG_LEN(skb->data));
                pr_debug("capi: DATA_B3_RESP %u len=%d => ldisc\n",
                         datahandle, skb->len);
                ld->ops->receive_buf(tty, skb->data, NULL, skb->len);
        } else {
                printk(KERN_ERR "capi: send DATA_B3_RESP failed=%x\n",
                       errcode);
                kfree_skb(nskb);

                if (errcode == CAPI_SENDQUEUEFULL)
                        goto deref_ldisc;
        }

free_skb:
        ret = 0;
        kfree_skb(skb);

deref_ldisc:
        tty_ldisc_deref(ld);

deref_tty:
        tty_kref_put(tty);
        return ret;
}

static void handle_minor_recv(struct capiminor *mp)
{
        struct sk_buff *skb;

        while ((skb = skb_dequeue(&mp->inqueue)) != NULL)
                if (handle_recv_skb(mp, skb) < 0) {
                        skb_queue_head(&mp->inqueue, skb);
                        return;
                }
}

static void handle_minor_send(struct capiminor *mp)
{
        struct tty_struct *tty;
        struct sk_buff *skb;
        u16 len;
        u16 errcode;
        u16 datahandle;

        tty = tty_port_tty_get(&mp->port);
        if (!tty)
                return;

        if (mp->ttyoutstop) {
                pr_debug("capi: send: tty stopped\n");
                tty_kref_put(tty);
                return;
        }

        while (1) {
                spin_lock_bh(&mp->outlock);
                skb = __skb_dequeue(&mp->outqueue);
                if (!skb) {
                        spin_unlock_bh(&mp->outlock);
                        break;
                }
                len = (u16)skb->len;
                mp->outbytes -= len;
                spin_unlock_bh(&mp->outlock);

                datahandle = atomic_inc_return(&mp->datahandle);
                skb_push(skb, CAPI_DATA_B3_REQ_LEN);
                memset(skb->data, 0, CAPI_DATA_B3_REQ_LEN);
                capimsg_setu16(skb->data, 0, CAPI_DATA_B3_REQ_LEN);
                capimsg_setu16(skb->data, 2, mp->ap->applid);
                capimsg_setu8 (skb->data, 4, CAPI_DATA_B3);
                capimsg_setu8 (skb->data, 5, CAPI_REQ);
                capimsg_setu16(skb->data, 6, atomic_inc_return(&mp->msgid));
                capimsg_setu32(skb->data, 8, mp->ncci); /* NCCI */
                capimsg_setu32(skb->data, 12, (u32)(long)skb->data);/* Data32 */
                capimsg_setu16(skb->data, 16, len);     /* Data length */
                capimsg_setu16(skb->data, 18, datahandle);
                capimsg_setu16(skb->data, 20, 0);       /* Flags */

                if (capiminor_add_ack(mp, datahandle) < 0) {
                        skb_pull(skb, CAPI_DATA_B3_REQ_LEN);

                        spin_lock_bh(&mp->outlock);
                        __skb_queue_head(&mp->outqueue, skb);
                        mp->outbytes += len;
                        spin_unlock_bh(&mp->outlock);

                        break;
                }
                errcode = capi20_put_message(mp->ap, skb);
                if (errcode == CAPI_NOERROR) {
                        pr_debug("capi: DATA_B3_REQ %u len=%u\n",
                                 datahandle, len);
                        continue;
                }
                capiminor_del_ack(mp, datahandle);

                if (errcode == CAPI_SENDQUEUEFULL) {
                        skb_pull(skb, CAPI_DATA_B3_REQ_LEN);

                        spin_lock_bh(&mp->outlock);
                        __skb_queue_head(&mp->outqueue, skb);
                        mp->outbytes += len;
                        spin_unlock_bh(&mp->outlock);

                        break;
                }

                /* ups, drop packet */
                printk(KERN_ERR "capi: put_message = %x\n", errcode);
                kfree_skb(skb);
        }
        tty_kref_put(tty);
}

#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
/* -------- function called by lower level -------------------------- */

static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
{
        struct capidev *cdev = ap->private;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
        struct capiminor *mp;
        u16 datahandle;
        struct capincci *np;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

        mutex_lock(&cdev->lock);

        if (CAPIMSG_CMD(skb->data) == CAPI_CONNECT_B3_CONF) {
                u16 info = CAPIMSG_U16(skb->data, 12); // Info field
                if ((info & 0xff00) == 0)
                        capincci_alloc(cdev, CAPIMSG_NCCI(skb->data));
        }
        if (CAPIMSG_CMD(skb->data) == CAPI_CONNECT_B3_IND)
                capincci_alloc(cdev, CAPIMSG_NCCI(skb->data));

        if (CAPIMSG_COMMAND(skb->data) != CAPI_DATA_B3) {
                skb_queue_tail(&cdev->recvqueue, skb);
                wake_up_interruptible(&cdev->recvwait);
                goto unlock_out;
        }

#ifndef CONFIG_ISDN_CAPI_MIDDLEWARE
        skb_queue_tail(&cdev->recvqueue, skb);
        wake_up_interruptible(&cdev->recvwait);

#else /* CONFIG_ISDN_CAPI_MIDDLEWARE */

        np = capincci_find(cdev, CAPIMSG_CONTROL(skb->data));
        if (!np) {
                printk(KERN_ERR "BUG: capi_signal: ncci not found\n");
                skb_queue_tail(&cdev->recvqueue, skb);
                wake_up_interruptible(&cdev->recvwait);
                goto unlock_out;
        }

        mp = np->minorp;
        if (!mp) {
                skb_queue_tail(&cdev->recvqueue, skb);
                wake_up_interruptible(&cdev->recvwait);
                goto unlock_out;
        }
        if (CAPIMSG_SUBCOMMAND(skb->data) == CAPI_IND) {
                datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN + 4 + 4 + 2);
                pr_debug("capi_signal: DATA_B3_IND %u len=%d\n",
                         datahandle, skb->len-CAPIMSG_LEN(skb->data));
                skb_queue_tail(&mp->inqueue, skb);

                handle_minor_recv(mp);

        } else if (CAPIMSG_SUBCOMMAND(skb->data) == CAPI_CONF) {

                datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN + 4);
                pr_debug("capi_signal: DATA_B3_CONF %u 0x%x\n",
                         datahandle,
                         CAPIMSG_U16(skb->data, CAPIMSG_BASELEN + 4 + 2));
                kfree_skb(skb);
                capiminor_del_ack(mp, datahandle);
                tty_port_tty_wakeup(&mp->port);
                handle_minor_send(mp);

        } else {
                /* ups, let capi application handle it :-) */
                skb_queue_tail(&cdev->recvqueue, skb);
                wake_up_interruptible(&cdev->recvwait);
        }
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

unlock_out:
        mutex_unlock(&cdev->lock);
}

/* -------- file_operations for capidev ----------------------------- */

static ssize_t
capi_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
        struct capidev *cdev = file->private_data;
        struct sk_buff *skb;
        size_t copied;
        int err;

        if (!cdev->ap.applid)
                return -ENODEV;

        skb = skb_dequeue(&cdev->recvqueue);
        if (!skb) {
                if (file->f_flags & O_NONBLOCK)
                        return -EAGAIN;
                err = wait_event_interruptible(cdev->recvwait,
                                               (skb = skb_dequeue(&cdev->recvqueue)));
                if (err)
                        return err;
        }
        if (skb->len > count) {
                skb_queue_head(&cdev->recvqueue, skb);
                return -EMSGSIZE;
        }
        if (copy_to_user(buf, skb->data, skb->len)) {
                skb_queue_head(&cdev->recvqueue, skb);
                return -EFAULT;
        }
        copied = skb->len;

        kfree_skb(skb);

        return copied;
}

static ssize_t
capi_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
        struct capidev *cdev = file->private_data;
        struct sk_buff *skb;
        u16 mlen;

        if (!cdev->ap.applid)
                return -ENODEV;

        skb = alloc_skb(count, GFP_USER);
        if (!skb)
                return -ENOMEM;

        if (copy_from_user(skb_put(skb, count), buf, count)) {
                kfree_skb(skb);
                return -EFAULT;
        }
        mlen = CAPIMSG_LEN(skb->data);
        if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_REQ) {
                if ((size_t)(mlen + CAPIMSG_DATALEN(skb->data)) != count) {
                        kfree_skb(skb);
                        return -EINVAL;
                }
        } else {
                if (mlen != count) {
                        kfree_skb(skb);
                        return -EINVAL;
                }
        }
        CAPIMSG_SETAPPID(skb->data, cdev->ap.applid);

        if (CAPIMSG_CMD(skb->data) == CAPI_DISCONNECT_B3_RESP) {
                mutex_lock(&cdev->lock);
                capincci_free(cdev, CAPIMSG_NCCI(skb->data));
                mutex_unlock(&cdev->lock);
        }

        cdev->errcode = capi20_put_message(&cdev->ap, skb);

        if (cdev->errcode) {
                kfree_skb(skb);
                return -EIO;
        }
        return count;
}

static unsigned int
capi_poll(struct file *file, poll_table *wait)
{
        struct capidev *cdev = file->private_data;
        unsigned int mask = 0;

        if (!cdev->ap.applid)
                return POLLERR;

        poll_wait(file, &(cdev->recvwait), wait);
        mask = POLLOUT | POLLWRNORM;
        if (!skb_queue_empty(&cdev->recvqueue))
                mask |= POLLIN | POLLRDNORM;
        return mask;
}

static int
capi_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        struct capidev *cdev = file->private_data;
        capi_ioctl_struct data;
        int retval = -EINVAL;
        void __user *argp = (void __user *)arg;

        switch (cmd) {
        case CAPI_REGISTER:
                mutex_lock(&cdev->lock);

                if (cdev->ap.applid) {
                        retval = -EEXIST;
                        goto register_out;
                }
                if (copy_from_user(&cdev->ap.rparam, argp,
                                   sizeof(struct capi_register_params))) {
                        retval = -EFAULT;
                        goto register_out;
                }
                cdev->ap.private = cdev;
                cdev->ap.recv_message = capi_recv_message;
                cdev->errcode = capi20_register(&cdev->ap);
                retval = (int)cdev->ap.applid;
                if (cdev->errcode) {
                        cdev->ap.applid = 0;
                        retval = -EIO;
                }

register_out:
                mutex_unlock(&cdev->lock);
                return retval;

        case CAPI_GET_VERSION:
                if (copy_from_user(&data.contr, argp,
                                   sizeof(data.contr)))
                        return -EFAULT;
                cdev->errcode = capi20_get_version(data.contr, &data.version);
                if (cdev->errcode)
                        return -EIO;
                if (copy_to_user(argp, &data.version,
                                 sizeof(data.version)))
                        return -EFAULT;
                return 0;

        case CAPI_GET_SERIAL:
                if (copy_from_user(&data.contr, argp,
                                   sizeof(data.contr)))
                        return -EFAULT;
                cdev->errcode = capi20_get_serial(data.contr, data.serial);
                if (cdev->errcode)
                        return -EIO;
                if (copy_to_user(argp, data.serial,
                                 sizeof(data.serial)))
                        return -EFAULT;
                return 0;

        case CAPI_GET_PROFILE:
                if (copy_from_user(&data.contr, argp,
                                   sizeof(data.contr)))
                        return -EFAULT;

                if (data.contr == 0) {
                        cdev->errcode = capi20_get_profile(data.contr, &data.profile);
                        if (cdev->errcode)
                                return -EIO;

                        retval = copy_to_user(argp,
                                              &data.profile.ncontroller,
                                              sizeof(data.profile.ncontroller));

                } else {
                        cdev->errcode = capi20_get_profile(data.contr, &data.profile);
                        if (cdev->errcode)
                                return -EIO;

                        retval = copy_to_user(argp, &data.profile,
                                              sizeof(data.profile));
                }
                if (retval)
                        return -EFAULT;
                return 0;

        case CAPI_GET_MANUFACTURER:
                if (copy_from_user(&data.contr, argp,
                                   sizeof(data.contr)))
                        return -EFAULT;
                cdev->errcode = capi20_get_manufacturer(data.contr, data.manufacturer);
                if (cdev->errcode)
                        return -EIO;

                if (copy_to_user(argp, data.manufacturer,
                                 sizeof(data.manufacturer)))
                        return -EFAULT;

                return 0;

        case CAPI_GET_ERRCODE:
                data.errcode = cdev->errcode;
                cdev->errcode = CAPI_NOERROR;
                if (arg) {
                        if (copy_to_user(argp, &data.errcode,
                                         sizeof(data.errcode)))
                                return -EFAULT;
                }
                return data.errcode;

        case CAPI_INSTALLED:
                if (capi20_isinstalled() == CAPI_NOERROR)
                        return 0;
                return -ENXIO;

        case CAPI_MANUFACTURER_CMD: {
                struct capi_manufacturer_cmd mcmd;
                if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;
                if (copy_from_user(&mcmd, argp, sizeof(mcmd)))
                        return -EFAULT;
                return capi20_manufacturer(mcmd.cmd, mcmd.data);
        }
        case CAPI_SET_FLAGS:
        case CAPI_CLR_FLAGS: {
                unsigned userflags;

                if (copy_from_user(&userflags, argp, sizeof(userflags)))
                        return -EFAULT;

                mutex_lock(&cdev->lock);
                if (cmd == CAPI_SET_FLAGS)
                        cdev->userflags |= userflags;
                else
                        cdev->userflags &= ~userflags;
                mutex_unlock(&cdev->lock);
                return 0;
        }
        case CAPI_GET_FLAGS:
                if (copy_to_user(argp, &cdev->userflags,
                                 sizeof(cdev->userflags)))
                        return -EFAULT;
                return 0;

#ifndef CONFIG_ISDN_CAPI_MIDDLEWARE
        case CAPI_NCCI_OPENCOUNT:
                return 0;

#else /* CONFIG_ISDN_CAPI_MIDDLEWARE */
        case CAPI_NCCI_OPENCOUNT: {
                struct capincci *nccip;
                unsigned ncci;
                int count = 0;

                if (copy_from_user(&ncci, argp, sizeof(ncci)))
                        return -EFAULT;

                mutex_lock(&cdev->lock);
                nccip = capincci_find(cdev, (u32)ncci);
                if (nccip)
                        count = capincci_minor_opencount(nccip);
                mutex_unlock(&cdev->lock);
                return count;
        }

        case CAPI_NCCI_GETUNIT: {
                struct capincci *nccip;
                struct capiminor *mp;
                unsigned ncci;
                int unit = -ESRCH;

                if (copy_from_user(&ncci, argp, sizeof(ncci)))
                        return -EFAULT;

                mutex_lock(&cdev->lock);
                nccip = capincci_find(cdev, (u32)ncci);
                if (nccip) {
                        mp = nccip->minorp;
                        if (mp)
                                unit = mp->minor;
                }
                mutex_unlock(&cdev->lock);
                return unit;
        }
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */

        default:
                return -EINVAL;
        }
}

static long
capi_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        int ret;

        mutex_lock(&capi_mutex);
        ret = capi_ioctl(file, cmd, arg);
        mutex_unlock(&capi_mutex);

        return ret;
}

static int capi_open(struct inode *inode, struct file *file)
{
        struct capidev *cdev;

        cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
        if (!cdev)
                return -ENOMEM;

        mutex_init(&cdev->lock);
        skb_queue_head_init(&cdev->recvqueue);
        init_waitqueue_head(&cdev->recvwait);
        INIT_LIST_HEAD(&cdev->nccis);
        file->private_data = cdev;

        mutex_lock(&capidev_list_lock);
        list_add_tail(&cdev->list, &capidev_list);
        mutex_unlock(&capidev_list_lock);

        return nonseekable_open(inode, file);
}

static int capi_release(struct inode *inode, struct file *file)
{
        struct capidev *cdev = file->private_data;

        mutex_lock(&capidev_list_lock);
        list_del(&cdev->list);
        mutex_unlock(&capidev_list_lock);

        if (cdev->ap.applid)
                capi20_release(&cdev->ap);
        skb_queue_purge(&cdev->recvqueue);
        capincci_free(cdev, 0xffffffff);

        kfree(cdev);
        return 0;
}

static const struct file_operations capi_fops =
{
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .read           = capi_read,
        .write          = capi_write,
        .poll           = capi_poll,
        .unlocked_ioctl = capi_unlocked_ioctl,
        .open           = capi_open,
        .release        = capi_release,
};

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
/* -------- tty_operations for capincci ----------------------------- */

static int
capinc_tty_install(struct tty_driver *driver, struct tty_struct *tty)
{
        struct capiminor *mp = capiminor_get(tty->index);
        int ret = tty_standard_install(driver, tty);

        if (ret == 0)
                tty->driver_data = mp;
        else
                capiminor_put(mp);
        return ret;
}

static void capinc_tty_cleanup(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;
        tty->driver_data = NULL;
        capiminor_put(mp);
}

static int capinc_tty_open(struct tty_struct *tty, struct file *filp)
{
        struct capiminor *mp = tty->driver_data;
        int err;

        err = tty_port_open(&mp->port, tty, filp);
        if (err)
                return err;

        handle_minor_recv(mp);
        return 0;
}

static void capinc_tty_close(struct tty_struct *tty, struct file *filp)
{
        struct capiminor *mp = tty->driver_data;

        tty_port_close(&mp->port, tty, filp);
}

static int capinc_tty_write(struct tty_struct *tty,
                            const unsigned char *buf, int count)
{
        struct capiminor *mp = tty->driver_data;
        struct sk_buff *skb;

        pr_debug("capinc_tty_write(count=%d)\n", count);

        spin_lock_bh(&mp->outlock);
        skb = mp->outskb;
        if (skb) {
                mp->outskb = NULL;
                __skb_queue_tail(&mp->outqueue, skb);
                mp->outbytes += skb->len;
        }

        skb = alloc_skb(CAPI_DATA_B3_REQ_LEN + count, GFP_ATOMIC);
        if (!skb) {
                printk(KERN_ERR "capinc_tty_write: alloc_skb failed\n");
                spin_unlock_bh(&mp->outlock);
                return -ENOMEM;
        }

        skb_reserve(skb, CAPI_DATA_B3_REQ_LEN);
        skb_put_data(skb, buf, count);

        __skb_queue_tail(&mp->outqueue, skb);
        mp->outbytes += skb->len;
        spin_unlock_bh(&mp->outlock);

        handle_minor_send(mp);

        return count;
}

static int capinc_tty_put_char(struct tty_struct *tty, unsigned char ch)
{
        struct capiminor *mp = tty->driver_data;
        bool invoke_send = false;
        struct sk_buff *skb;
        int ret = 1;

        pr_debug("capinc_put_char(%u)\n", ch);

        spin_lock_bh(&mp->outlock);
        skb = mp->outskb;
        if (skb) {
                if (skb_tailroom(skb) > 0) {
                        *(u8 *)skb_put(skb, 1) = ch;
                        goto unlock_out;
                }
                mp->outskb = NULL;
                __skb_queue_tail(&mp->outqueue, skb);
                mp->outbytes += skb->len;
                invoke_send = true;
        }

        skb = alloc_skb(CAPI_DATA_B3_REQ_LEN + CAPI_MAX_BLKSIZE, GFP_ATOMIC);
        if (skb) {
                skb_reserve(skb, CAPI_DATA_B3_REQ_LEN);
                *(u8 *)skb_put(skb, 1) = ch;
                mp->outskb = skb;
        } else {
                printk(KERN_ERR "capinc_put_char: char %u lost\n", ch);
                ret = 0;
        }

unlock_out:
        spin_unlock_bh(&mp->outlock);

        if (invoke_send)
                handle_minor_send(mp);

        return ret;
}

static void capinc_tty_flush_chars(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;
        struct sk_buff *skb;

        pr_debug("capinc_tty_flush_chars\n");

        spin_lock_bh(&mp->outlock);
        skb = mp->outskb;
        if (skb) {
                mp->outskb = NULL;
                __skb_queue_tail(&mp->outqueue, skb);
                mp->outbytes += skb->len;
                spin_unlock_bh(&mp->outlock);

                handle_minor_send(mp);
        } else
                spin_unlock_bh(&mp->outlock);

        handle_minor_recv(mp);
}

static int capinc_tty_write_room(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;
        int room;

        room = CAPINC_MAX_SENDQUEUE-skb_queue_len(&mp->outqueue);
        room *= CAPI_MAX_BLKSIZE;
        pr_debug("capinc_tty_write_room = %d\n", room);
        return room;
}

static int capinc_tty_chars_in_buffer(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;

        pr_debug("capinc_tty_chars_in_buffer = %d nack=%d sq=%d rq=%d\n",
                 mp->outbytes, mp->nack,
                 skb_queue_len(&mp->outqueue),
                 skb_queue_len(&mp->inqueue));
        return mp->outbytes;
}

static int capinc_tty_ioctl(struct tty_struct *tty,
                            unsigned int cmd, unsigned long arg)
{
        return -ENOIOCTLCMD;
}

static void capinc_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
{
        pr_debug("capinc_tty_set_termios\n");
}

static void capinc_tty_throttle(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;
        pr_debug("capinc_tty_throttle\n");
        mp->ttyinstop = 1;
}

static void capinc_tty_unthrottle(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;

        pr_debug("capinc_tty_unthrottle\n");
        mp->ttyinstop = 0;
        handle_minor_recv(mp);
}

static void capinc_tty_stop(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;

        pr_debug("capinc_tty_stop\n");
        mp->ttyoutstop = 1;
}

static void capinc_tty_start(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;

        pr_debug("capinc_tty_start\n");
        mp->ttyoutstop = 0;
        handle_minor_send(mp);
}

static void capinc_tty_hangup(struct tty_struct *tty)
{
        struct capiminor *mp = tty->driver_data;

        pr_debug("capinc_tty_hangup\n");
        tty_port_hangup(&mp->port);
}

static int capinc_tty_break_ctl(struct tty_struct *tty, int state)
{
        pr_debug("capinc_tty_break_ctl(%d)\n", state);
        return 0;
}

static void capinc_tty_flush_buffer(struct tty_struct *tty)
{
        pr_debug("capinc_tty_flush_buffer\n");
}

static void capinc_tty_set_ldisc(struct tty_struct *tty)
{
        pr_debug("capinc_tty_set_ldisc\n");
}

static void capinc_tty_send_xchar(struct tty_struct *tty, char ch)
{
        pr_debug("capinc_tty_send_xchar(%d)\n", ch);
}

static const struct tty_operations capinc_ops = {
        .open = capinc_tty_open,
        .close = capinc_tty_close,
        .write = capinc_tty_write,
        .put_char = capinc_tty_put_char,
        .flush_chars = capinc_tty_flush_chars,
        .write_room = capinc_tty_write_room,
        .chars_in_buffer = capinc_tty_chars_in_buffer,
        .ioctl = capinc_tty_ioctl,
        .set_termios = capinc_tty_set_termios,
        .throttle = capinc_tty_throttle,
        .unthrottle = capinc_tty_unthrottle,
        .stop = capinc_tty_stop,
        .start = capinc_tty_start,
        .hangup = capinc_tty_hangup,
        .break_ctl = capinc_tty_break_ctl,
        .flush_buffer = capinc_tty_flush_buffer,
        .set_ldisc = capinc_tty_set_ldisc,
        .send_xchar = capinc_tty_send_xchar,
        .install = capinc_tty_install,
        .cleanup = capinc_tty_cleanup,
};

static int __init capinc_tty_init(void)
{
        struct tty_driver *drv;
        int err;

        if (capi_ttyminors > CAPINC_MAX_PORTS)
                capi_ttyminors = CAPINC_MAX_PORTS;
        if (capi_ttyminors <= 0)
                capi_ttyminors = CAPINC_NR_PORTS;

        capiminors = kzalloc(sizeof(struct capiminor *) * capi_ttyminors,
                             GFP_KERNEL);
        if (!capiminors)
                return -ENOMEM;

        drv = alloc_tty_driver(capi_ttyminors);
        if (!drv) {
                kfree(capiminors);
                return -ENOMEM;
        }
        drv->driver_name = "capi_nc";
        drv->name = "capi!";
        drv->major = 0;
        drv->minor_start = 0;
        drv->type = TTY_DRIVER_TYPE_SERIAL;
        drv->subtype = SERIAL_TYPE_NORMAL;
        drv->init_termios = tty_std_termios;
        drv->init_termios.c_iflag = ICRNL;
        drv->init_termios.c_oflag = OPOST | ONLCR;
        drv->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        drv->init_termios.c_lflag = 0;
        drv->flags =
                TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS |
                TTY_DRIVER_DYNAMIC_DEV;
        tty_set_operations(drv, &capinc_ops);

        err = tty_register_driver(drv);
        if (err) {
                put_tty_driver(drv);
                kfree(capiminors);
                printk(KERN_ERR "Couldn't register capi_nc driver\n");
                return err;
        }
        capinc_tty_driver = drv;
        return 0;
}

static void __exit capinc_tty_exit(void)
{
        tty_unregister_driver(capinc_tty_driver);
        put_tty_driver(capinc_tty_driver);
        kfree(capiminors);
}

#else /* !CONFIG_ISDN_CAPI_MIDDLEWARE */

static inline int capinc_tty_init(void)
{
        return 0;
}

static inline void capinc_tty_exit(void) { }

#endif /* !CONFIG_ISDN_CAPI_MIDDLEWARE */

/* -------- /proc functions ----------------------------------------- */

/*
 * /proc/capi/capi20:
 *  minor applid nrecvctlpkt nrecvdatapkt nsendctlpkt nsenddatapkt
 */
static int capi20_proc_show(struct seq_file *m, void *v)
{
        struct capidev *cdev;
        struct list_head *l;

        mutex_lock(&capidev_list_lock);
        list_for_each(l, &capidev_list) {
                cdev = list_entry(l, struct capidev, list);
                seq_printf(m, "0 %d %lu %lu %lu %lu\n",
                           cdev->ap.applid,
                           cdev->ap.nrecvctlpkt,
                           cdev->ap.nrecvdatapkt,
                           cdev->ap.nsentctlpkt,
                           cdev->ap.nsentdatapkt);
        }
        mutex_unlock(&capidev_list_lock);
        return 0;
}

static int capi20_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, capi20_proc_show, NULL);
}

static const struct file_operations capi20_proc_fops = {
        .owner          = THIS_MODULE,
        .open           = capi20_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

/*
 * /proc/capi/capi20ncci:
 *  applid ncci
 */
static int capi20ncci_proc_show(struct seq_file *m, void *v)
{
        struct capidev *cdev;
        struct capincci *np;

        mutex_lock(&capidev_list_lock);
        list_for_each_entry(cdev, &capidev_list, list) {
                mutex_lock(&cdev->lock);
                list_for_each_entry(np, &cdev->nccis, list)
                        seq_printf(m, "%d 0x%x\n", cdev->ap.applid, np->ncci);
                mutex_unlock(&cdev->lock);
        }
        mutex_unlock(&capidev_list_lock);
        return 0;
}

static int capi20ncci_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, capi20ncci_proc_show, NULL);
}

static const struct file_operations capi20ncci_proc_fops = {
        .owner          = THIS_MODULE,
        .open           = capi20ncci_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static void __init proc_init(void)
{
        proc_create("capi/capi20", 0, NULL, &capi20_proc_fops);
        proc_create("capi/capi20ncci", 0, NULL, &capi20ncci_proc_fops);
}

static void __exit proc_exit(void)
{
        remove_proc_entry("capi/capi20", NULL);
        remove_proc_entry("capi/capi20ncci", NULL);
}

/* -------- init function and module interface ---------------------- */


static int __init capi_init(void)
{
        const char *compileinfo;
        int major_ret;

        major_ret = register_chrdev(capi_major, "capi20", &capi_fops);
        if (major_ret < 0) {
                printk(KERN_ERR "capi20: unable to get major %d\n", capi_major);
                return major_ret;
        }
        capi_class = class_create(THIS_MODULE, "capi");
        if (IS_ERR(capi_class)) {
                unregister_chrdev(capi_major, "capi20");
                return PTR_ERR(capi_class);
        }

        device_create(capi_class, NULL, MKDEV(capi_major, 0), NULL, "capi20");

        if (capinc_tty_init() < 0) {
                device_destroy(capi_class, MKDEV(capi_major, 0));
                class_destroy(capi_class);
                unregister_chrdev(capi_major, "capi20");
                return -ENOMEM;
        }

        proc_init();

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
        compileinfo = " (middleware)";
#else
        compileinfo = " (no middleware)";
#endif
        printk(KERN_NOTICE "CAPI 2.0 started up with major %d%s\n",
               capi_major, compileinfo);

        return 0;
}

static void __exit capi_exit(void)
{
        proc_exit();

        device_destroy(capi_class, MKDEV(capi_major, 0));
        class_destroy(capi_class);
        unregister_chrdev(capi_major, "capi20");

        capinc_tty_exit();
}

module_init(capi_init);
module_exit(capi_exit);