capi.c

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/* $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 <[email protected]>
 *
 * 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 {
    struct kref kref;

    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 const struct tty_port_operations capiminor_port_ops; /* we have none */

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;
    }

    kref_init(&mp->kref);

    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:
    kfree(mp);
    return NULL;
}

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

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

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

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

    return mp;
}

static inline void capiminor_put(struct capiminor *mp)
{
    kref_put(&mp->kref, capiminor_destroy);
}

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 tty_struct *tty;
    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 = tty_port_tty_get(&mp->port);
        if (tty) {
            tty_wakeup(tty);
            tty_kref_put(tty);
        }
        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);
    memcpy(skb_put(skb, count), 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) {
            *(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);
        *(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 capi_minor *) * 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, "capi");

    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);