isdnloop.c

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/* $Id: isdnloop.c,v 1.11.6.7 2001/11/11 19:54:31 kai Exp $
 *
 * ISDN low-level module implementing a dummy loop driver.
 *
 * Copyright 1997 by Fritz Elfert ([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/interrupt.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/sched.h>
#include "isdnloop.h"

static char *isdnloop_id = "loop0";

MODULE_DESCRIPTION("ISDN4Linux: Pseudo Driver that simulates an ISDN card");
MODULE_AUTHOR("Fritz Elfert");
MODULE_LICENSE("GPL");
module_param(isdnloop_id, charp, 0);
MODULE_PARM_DESC(isdnloop_id, "ID-String of first card");

static int isdnloop_addcard(char *);

/*
 * Free queue completely.
 *
 * Parameter:
 *   card    = pointer to card struct
 *   channel = channel number
 */
static void
isdnloop_free_queue(isdnloop_card *card, int channel)
{
    struct sk_buff_head *queue = &card->bqueue[channel];

    skb_queue_purge(queue);
    card->sndcount[channel] = 0;
}

/*
 * Send B-Channel data to another virtual card.
 * This routine is called via timer-callback from isdnloop_pollbchan().
 *
 * Parameter:
 *   card = pointer to card struct.
 *   ch   = channel number (0-based)
 */
static void
isdnloop_bchan_send(isdnloop_card *card, int ch)
{
    isdnloop_card *rcard = card->rcard[ch];
    int rch = card->rch[ch], len, ack;
    struct sk_buff *skb;
    isdn_ctrl cmd;

    while (card->sndcount[ch]) {
        if ((skb = skb_dequeue(&card->bqueue[ch]))) {
            len = skb->len;
            card->sndcount[ch] -= len;
            ack = *(skb->head); /* used as scratch area */
            cmd.driver = card->myid;
            cmd.arg = ch;
            if (rcard) {
                rcard->interface.rcvcallb_skb(rcard->myid, rch, skb);
            } else {
                printk(KERN_WARNING "isdnloop: no rcard, skb dropped\n");
                dev_kfree_skb(skb);

            };
            cmd.command = ISDN_STAT_BSENT;
            cmd.parm.length = len;
            card->interface.statcallb(&cmd);
        } else
            card->sndcount[ch] = 0;
    }
}

/*
 * Send/Receive Data to/from the B-Channel.
 * This routine is called via timer-callback.
 * It schedules itself while any B-Channel is open.
 *
 * Parameter:
 *   data = pointer to card struct, set by kernel timer.data
 */
static void
isdnloop_pollbchan(unsigned long data)
{
    isdnloop_card *card = (isdnloop_card *) data;
    unsigned long flags;

    if (card->flags & ISDNLOOP_FLAGS_B1ACTIVE)
        isdnloop_bchan_send(card, 0);
    if (card->flags & ISDNLOOP_FLAGS_B2ACTIVE)
        isdnloop_bchan_send(card, 1);
    if (card->flags & (ISDNLOOP_FLAGS_B1ACTIVE | ISDNLOOP_FLAGS_B2ACTIVE)) {
        /* schedule b-channel polling again */
        spin_lock_irqsave(&card->isdnloop_lock, flags);
        card->rb_timer.expires = jiffies + ISDNLOOP_TIMER_BCREAD;
        add_timer(&card->rb_timer);
        card->flags |= ISDNLOOP_FLAGS_RBTIMER;
        spin_unlock_irqrestore(&card->isdnloop_lock, flags);
    } else
        card->flags &= ~ISDNLOOP_FLAGS_RBTIMER;
}

/*
 * Parse ICN-type setup string and fill fields of setup-struct
 * with parsed data.
 *
 * Parameter:
 *   setup = setup string, format: [caller-id],si1,si2,[called-id]
 *   cmd   = pointer to struct to be filled.
 */
static void
isdnloop_parse_setup(char *setup, isdn_ctrl *cmd)
{
    char *t = setup;
    char *s = strchr(t, ',');

    *s++ = '\0';
    strlcpy(cmd->parm.setup.phone, t, sizeof(cmd->parm.setup.phone));
    s = strchr(t = s, ',');
    *s++ = '\0';
    if (!strlen(t))
        cmd->parm.setup.si1 = 0;
    else
        cmd->parm.setup.si1 = simple_strtoul(t, NULL, 10);
    s = strchr(t = s, ',');
    *s++ = '\0';
    if (!strlen(t))
        cmd->parm.setup.si2 = 0;
    else
        cmd->parm.setup.si2 =
            simple_strtoul(t, NULL, 10);
    strlcpy(cmd->parm.setup.eazmsn, s, sizeof(cmd->parm.setup.eazmsn));
    cmd->parm.setup.plan = 0;
    cmd->parm.setup.screen = 0;
}

typedef struct isdnloop_stat {
    char *statstr;
    int command;
    int action;
} isdnloop_stat;
/* *INDENT-OFF* */
static isdnloop_stat isdnloop_stat_table[] =
{
    {"BCON_",          ISDN_STAT_BCONN, 1}, /* B-Channel connected        */
    {"BDIS_",          ISDN_STAT_BHUP,  2}, /* B-Channel disconnected     */
    {"DCON_",          ISDN_STAT_DCONN, 0}, /* D-Channel connected        */
    {"DDIS_",          ISDN_STAT_DHUP,  0}, /* D-Channel disconnected     */
    {"DCAL_I",         ISDN_STAT_ICALL, 3}, /* Incoming call dialup-line  */
    {"DSCA_I",         ISDN_STAT_ICALL, 3}, /* Incoming call 1TR6-SPV     */
    {"FCALL",          ISDN_STAT_ICALL, 4}, /* Leased line connection up  */
    {"CIF",            ISDN_STAT_CINF,  5}, /* Charge-info, 1TR6-type     */
    {"AOC",            ISDN_STAT_CINF,  6}, /* Charge-info, DSS1-type     */
    {"CAU",            ISDN_STAT_CAUSE, 7}, /* Cause code                 */
    {"TEI OK",         ISDN_STAT_RUN,   0}, /* Card connected to wallplug */
    {"E_L1: ACT FAIL", ISDN_STAT_BHUP,  8}, /* Layer-1 activation failed  */
    {"E_L2: DATA LIN", ISDN_STAT_BHUP,  8}, /* Layer-2 data link lost     */
    {"E_L1: ACTIVATION FAILED",
     ISDN_STAT_BHUP,  8},         /* Layer-1 activation failed  */
    {NULL, 0, -1}
};
/* *INDENT-ON* */


/*
 * Parse Status message-strings from virtual card.
 * Depending on status, call statcallb for sending messages to upper
 * levels. Also set/reset B-Channel active-flags.
 *
 * Parameter:
 *   status  = status string to parse.
 *   channel = channel where message comes from.
 *   card    = card where message comes from.
 */
static void
isdnloop_parse_status(u_char *status, int channel, isdnloop_card *card)
{
    isdnloop_stat *s = isdnloop_stat_table;
    int action = -1;
    isdn_ctrl cmd;

    while (s->statstr) {
        if (!strncmp(status, s->statstr, strlen(s->statstr))) {
            cmd.command = s->command;
            action = s->action;
            break;
        }
        s++;
    }
    if (action == -1)
        return;
    cmd.driver = card->myid;
    cmd.arg = channel;
    switch (action) {
    case 1:
        /* BCON_x */
        card->flags |= (channel) ?
            ISDNLOOP_FLAGS_B2ACTIVE : ISDNLOOP_FLAGS_B1ACTIVE;
        break;
    case 2:
        /* BDIS_x */
        card->flags &= ~((channel) ?
                 ISDNLOOP_FLAGS_B2ACTIVE : ISDNLOOP_FLAGS_B1ACTIVE);
        isdnloop_free_queue(card, channel);
        break;
    case 3:
        /* DCAL_I and DSCA_I */
        isdnloop_parse_setup(status + 6, &cmd);
        break;
    case 4:
        /* FCALL */
        sprintf(cmd.parm.setup.phone, "LEASED%d", card->myid);
        sprintf(cmd.parm.setup.eazmsn, "%d", channel + 1);
        cmd.parm.setup.si1 = 7;
        cmd.parm.setup.si2 = 0;
        cmd.parm.setup.plan = 0;
        cmd.parm.setup.screen = 0;
        break;
    case 5:
        /* CIF */
        strlcpy(cmd.parm.num, status + 3, sizeof(cmd.parm.num));
        break;
    case 6:
        /* AOC */
        snprintf(cmd.parm.num, sizeof(cmd.parm.num), "%d",
             (int) simple_strtoul(status + 7, NULL, 16));
        break;
    case 7:
        /* CAU */
        status += 3;
        if (strlen(status) == 4)
            snprintf(cmd.parm.num, sizeof(cmd.parm.num), "%s%c%c",
                 status + 2, *status, *(status + 1));
        else
            strlcpy(cmd.parm.num, status + 1, sizeof(cmd.parm.num));
        break;
    case 8:
        /* Misc Errors on L1 and L2 */
        card->flags &= ~ISDNLOOP_FLAGS_B1ACTIVE;
        isdnloop_free_queue(card, 0);
        cmd.arg = 0;
        cmd.driver = card->myid;
        card->interface.statcallb(&cmd);
        cmd.command = ISDN_STAT_DHUP;
        cmd.arg = 0;
        cmd.driver = card->myid;
        card->interface.statcallb(&cmd);
        cmd.command = ISDN_STAT_BHUP;
        card->flags &= ~ISDNLOOP_FLAGS_B2ACTIVE;
        isdnloop_free_queue(card, 1);
        cmd.arg = 1;
        cmd.driver = card->myid;
        card->interface.statcallb(&cmd);
        cmd.command = ISDN_STAT_DHUP;
        cmd.arg = 1;
        cmd.driver = card->myid;
        break;
    }
    card->interface.statcallb(&cmd);
}

/*
 * Store a cwcharacter into ringbuffer for reading from /dev/isdnctrl
 *
 * Parameter:
 *   card = pointer to card struct.
 *   c    = char to store.
 */
static void
isdnloop_putmsg(isdnloop_card *card, unsigned char c)
{
    ulong flags;

    spin_lock_irqsave(&card->isdnloop_lock, flags);
    *card->msg_buf_write++ = (c == 0xff) ? '\n' : c;
    if (card->msg_buf_write == card->msg_buf_read) {
        if (++card->msg_buf_read > card->msg_buf_end)
            card->msg_buf_read = card->msg_buf;
    }
    if (card->msg_buf_write > card->msg_buf_end)
        card->msg_buf_write = card->msg_buf;
    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
}

/*
 * Poll a virtual cards message queue.
 * If there are new status-replies from the card, copy them to
 * ringbuffer for reading on /dev/isdnctrl and call
 * isdnloop_parse_status() for processing them. Watch for special
 * Firmware bootmessage and parse it, to get the D-Channel protocol.
 * If there are B-Channels open, initiate a timer-callback to
 * isdnloop_pollbchan().
 * This routine is called periodically via timer interrupt.
 *
 * Parameter:
 *   data = pointer to card struct
 */
static void
isdnloop_polldchan(unsigned long data)
{
    isdnloop_card *card = (isdnloop_card *) data;
    struct sk_buff *skb;
    int avail;
    int left;
    u_char c;
    int ch;
    unsigned long flags;
    u_char *p;
    isdn_ctrl cmd;

    if ((skb = skb_dequeue(&card->dqueue)))
        avail = skb->len;
    else
        avail = 0;
    for (left = avail; left > 0; left--) {
        c = *skb->data;
        skb_pull(skb, 1);
        isdnloop_putmsg(card, c);
        card->imsg[card->iptr] = c;
        if (card->iptr < 59)
            card->iptr++;
        if (!skb->len) {
            avail++;
            isdnloop_putmsg(card, '\n');
            card->imsg[card->iptr] = 0;
            card->iptr = 0;
            if (card->imsg[0] == '0' && card->imsg[1] >= '0' &&
                card->imsg[1] <= '2' && card->imsg[2] == ';') {
                ch = (card->imsg[1] - '0') - 1;
                p = &card->imsg[3];
                isdnloop_parse_status(p, ch, card);
            } else {
                p = card->imsg;
                if (!strncmp(p, "DRV1.", 5)) {
                    printk(KERN_INFO "isdnloop: (%s) %s\n", CID, p);
                    if (!strncmp(p + 7, "TC", 2)) {
                        card->ptype = ISDN_PTYPE_1TR6;
                        card->interface.features |= ISDN_FEATURE_P_1TR6;
                        printk(KERN_INFO
                               "isdnloop: (%s) 1TR6-Protocol loaded and running\n", CID);
                    }
                    if (!strncmp(p + 7, "EC", 2)) {
                        card->ptype = ISDN_PTYPE_EURO;
                        card->interface.features |= ISDN_FEATURE_P_EURO;
                        printk(KERN_INFO
                               "isdnloop: (%s) Euro-Protocol loaded and running\n", CID);
                    }
                    continue;

                }
            }
        }
    }
    if (avail) {
        cmd.command = ISDN_STAT_STAVAIL;
        cmd.driver = card->myid;
        cmd.arg = avail;
        card->interface.statcallb(&cmd);
    }
    if (card->flags & (ISDNLOOP_FLAGS_B1ACTIVE | ISDNLOOP_FLAGS_B2ACTIVE))
        if (!(card->flags & ISDNLOOP_FLAGS_RBTIMER)) {
            /* schedule b-channel polling */
            card->flags |= ISDNLOOP_FLAGS_RBTIMER;
            spin_lock_irqsave(&card->isdnloop_lock, flags);
            del_timer(&card->rb_timer);
            card->rb_timer.function = isdnloop_pollbchan;
            card->rb_timer.data = (unsigned long) card;
            card->rb_timer.expires = jiffies + ISDNLOOP_TIMER_BCREAD;
            add_timer(&card->rb_timer);
            spin_unlock_irqrestore(&card->isdnloop_lock, flags);
        }
    /* schedule again */
    spin_lock_irqsave(&card->isdnloop_lock, flags);
    card->st_timer.expires = jiffies + ISDNLOOP_TIMER_DCREAD;
    add_timer(&card->st_timer);
    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
}

/*
 * Append a packet to the transmit buffer-queue.
 *
 * Parameter:
 *   channel = Number of B-channel
 *   skb     = packet to send.
 *   card    = pointer to card-struct
 * Return:
 *   Number of bytes transferred, -E??? on error
 */
static int
isdnloop_sendbuf(int channel, struct sk_buff *skb, isdnloop_card *card)
{
    int len = skb->len;
    unsigned long flags;
    struct sk_buff *nskb;

    if (len > 4000) {
        printk(KERN_WARNING
               "isdnloop: Send packet too large\n");
        return -EINVAL;
    }
    if (len) {
        if (!(card->flags & (channel) ? ISDNLOOP_FLAGS_B2ACTIVE : ISDNLOOP_FLAGS_B1ACTIVE))
            return 0;
        if (card->sndcount[channel] > ISDNLOOP_MAX_SQUEUE)
            return 0;
        spin_lock_irqsave(&card->isdnloop_lock, flags);
        nskb = dev_alloc_skb(skb->len);
        if (nskb) {
            skb_copy_from_linear_data(skb,
                          skb_put(nskb, len), len);
            skb_queue_tail(&card->bqueue[channel], nskb);
            dev_kfree_skb(skb);
        } else
            len = 0;
        card->sndcount[channel] += len;
        spin_unlock_irqrestore(&card->isdnloop_lock, flags);
    }
    return len;
}

/*
 * Read the messages from the card's ringbuffer
 *
 * Parameter:
 *   buf  = pointer to buffer.
 *   len  = number of bytes to read.
 *   user = flag, 1: called from userlevel 0: called from kernel.
 *   card = pointer to card struct.
 * Return:
 *   number of bytes actually transferred.
 */
static int
isdnloop_readstatus(u_char __user *buf, int len, isdnloop_card *card)
{
    int count;
    u_char __user *p;

    for (p = buf, count = 0; count < len; p++, count++) {
        if (card->msg_buf_read == card->msg_buf_write)
            return count;
        if (put_user(*card->msg_buf_read++, p))
            return -EFAULT;
        if (card->msg_buf_read > card->msg_buf_end)
            card->msg_buf_read = card->msg_buf;
    }
    return count;
}

/*
 * Simulate a card's response by appending it to the cards
 * message queue.
 *
 * Parameter:
 *   card = pointer to card struct.
 *   s    = pointer to message-string.
 *   ch   = channel: 0 = generic messages, 1 and 2 = D-channel messages.
 * Return:
 *   0 on success, 1 on memory squeeze.
 */
static int
isdnloop_fake(isdnloop_card *card, char *s, int ch)
{
    struct sk_buff *skb;
    int len = strlen(s) + ((ch >= 0) ? 3 : 0);

    if (!(skb = dev_alloc_skb(len))) {
        printk(KERN_WARNING "isdnloop: Out of memory in isdnloop_fake\n");
        return 1;
    }
    if (ch >= 0)
        sprintf(skb_put(skb, 3), "%02d;", ch);
    memcpy(skb_put(skb, strlen(s)), s, strlen(s));
    skb_queue_tail(&card->dqueue, skb);
    return 0;
}
/* *INDENT-OFF* */
static isdnloop_stat isdnloop_cmd_table[] =
{
    {"BCON_R",         0,  1},  /* B-Channel connect        */
    {"BCON_I",         0, 17},  /* B-Channel connect ind    */
    {"BDIS_R",         0,  2},  /* B-Channel disconnect     */
    {"DDIS_R",         0,  3},  /* D-Channel disconnect     */
    {"DCON_R",         0, 16},  /* D-Channel connect        */
    {"DSCA_R",         0,  4},  /* Dial 1TR6-SPV     */
    {"DCAL_R",         0,  5},  /* Dial */
    {"EAZC",           0,  6},  /* Clear EAZ listener */
    {"EAZ",            0,  7},  /* Set EAZ listener */
    {"SEEAZ",          0,  8},  /* Get EAZ listener */
    {"MSN",            0,  9},  /* Set/Clear MSN listener */
    {"MSALL",          0, 10},  /* Set multi MSN listeners */
    {"SETSIL",         0, 11},  /* Set SI list     */
    {"SEESIL",         0, 12},  /* Get SI list     */
    {"SILC",           0, 13},  /* Clear SI list     */
    {"LOCK",           0, -1},  /* LOCK channel     */
    {"UNLOCK",         0, -1},  /* UNLOCK channel     */
    {"FV2ON",          1, 14},  /* Leased mode on               */
    {"FV2OFF",         1, 15},  /* Leased mode off              */
    {NULL, 0, -1}
};
/* *INDENT-ON* */


/*
 * Simulate an error-response from a card.
 *
 * Parameter:
 *   card = pointer to card struct.
 */
static void
isdnloop_fake_err(isdnloop_card *card)
{
    char buf[60];

    sprintf(buf, "E%s", card->omsg);
    isdnloop_fake(card, buf, -1);
    isdnloop_fake(card, "NAK", -1);
}

static u_char ctable_eu[] =
{0x00, 0x11, 0x01, 0x12};
static u_char ctable_1t[] =
{0x00, 0x3b, 0x01, 0x3a};

/*
 * Assemble a simplified cause message depending on the
 * D-channel protocol used.
 *
 * Parameter:
 *   card = pointer to card struct.
 *   loc  = location: 0 = local, 1 = remote.
 *   cau  = cause: 1 = busy, 2 = nonexistent callerid, 3 = no user responding.
 * Return:
 *   Pointer to buffer containing the assembled message.
 */
static char *
isdnloop_unicause(isdnloop_card *card, int loc, int cau)
{
    static char buf[6];

    switch (card->ptype) {
    case ISDN_PTYPE_EURO:
        sprintf(buf, "E%02X%02X", (loc) ? 4 : 2, ctable_eu[cau]);
        break;
    case ISDN_PTYPE_1TR6:
        sprintf(buf, "%02X44", ctable_1t[cau]);
        break;
    default:
        return ("0000");
    }
    return (buf);
}

/*
 * Release a virtual connection. Called from timer interrupt, when
 * called party did not respond.
 *
 * Parameter:
 *   card = pointer to card struct.
 *   ch   = channel (0-based)
 */
static void
isdnloop_atimeout(isdnloop_card *card, int ch)
{
    unsigned long flags;
    char buf[60];

    spin_lock_irqsave(&card->isdnloop_lock, flags);
    if (card->rcard) {
        isdnloop_fake(card->rcard[ch], "DDIS_I", card->rch[ch] + 1);
        card->rcard[ch]->rcard[card->rch[ch]] = NULL;
        card->rcard[ch] = NULL;
    }
    isdnloop_fake(card, "DDIS_I", ch + 1);
    /* No user responding */
    sprintf(buf, "CAU%s", isdnloop_unicause(card, 1, 3));
    isdnloop_fake(card, buf, ch + 1);
    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
}

/*
 * Wrapper for isdnloop_atimeout().
 */
static void
isdnloop_atimeout0(unsigned long data)
{
    isdnloop_card *card = (isdnloop_card *) data;
    isdnloop_atimeout(card, 0);
}

/*
 * Wrapper for isdnloop_atimeout().
 */
static void
isdnloop_atimeout1(unsigned long data)
{
    isdnloop_card *card = (isdnloop_card *) data;
    isdnloop_atimeout(card, 1);
}

/*
 * Install a watchdog for a user, not responding.
 *
 * Parameter:
 *   card = pointer to card struct.
 *   ch   = channel to watch for.
 */
static void
isdnloop_start_ctimer(isdnloop_card *card, int ch)
{
    unsigned long flags;

    spin_lock_irqsave(&card->isdnloop_lock, flags);
    init_timer(&card->c_timer[ch]);
    card->c_timer[ch].expires = jiffies + ISDNLOOP_TIMER_ALERTWAIT;
    if (ch)
        card->c_timer[ch].function = isdnloop_atimeout1;
    else
        card->c_timer[ch].function = isdnloop_atimeout0;
    card->c_timer[ch].data = (unsigned long) card;
    add_timer(&card->c_timer[ch]);
    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
}

/*
 * Kill a pending channel watchdog.
 *
 * Parameter:
 *   card = pointer to card struct.
 *   ch   = channel (0-based).
 */
static void
isdnloop_kill_ctimer(isdnloop_card *card, int ch)
{
    unsigned long flags;

    spin_lock_irqsave(&card->isdnloop_lock, flags);
    del_timer(&card->c_timer[ch]);
    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
}

static u_char si2bit[] =
{0, 1, 0, 0, 0, 2, 0, 4, 0, 0};
static u_char bit2si[] =
{1, 5, 7};

/*
 * Try finding a listener for an outgoing call.
 *
 * Parameter:
 *   card = pointer to calling card.
 *   p    = pointer to ICN-type setup-string.
 *   lch  = channel of calling card.
 *   cmd  = pointer to struct to be filled when parsing setup.
 * Return:
 *   0 = found match, alerting should happen.
 *   1 = found matching number but it is busy.
 *   2 = no matching listener.
 *   3 = found matching number but SI does not match.
 */
static int
isdnloop_try_call(isdnloop_card *card, char *p, int lch, isdn_ctrl *cmd)
{
    isdnloop_card *cc = cards;
    unsigned long flags;
    int ch;
    int num_match;
    int i;
    char *e;
    char nbuf[32];

    isdnloop_parse_setup(p, cmd);
    while (cc) {
        for (ch = 0; ch < 2; ch++) {
            /* Exclude ourself */
            if ((cc == card) && (ch == lch))
                continue;
            num_match = 0;
            switch (cc->ptype) {
            case ISDN_PTYPE_EURO:
                for (i = 0; i < 3; i++)
                    if (!(strcmp(cc->s0num[i], cmd->parm.setup.phone)))
                        num_match = 1;
                break;
            case ISDN_PTYPE_1TR6:
                e = cc->eazlist[ch];
                while (*e) {
                    sprintf(nbuf, "%s%c", cc->s0num[0], *e);
                    if (!(strcmp(nbuf, cmd->parm.setup.phone)))
                        num_match = 1;
                    e++;
                }
            }
            if (num_match) {
                spin_lock_irqsave(&card->isdnloop_lock, flags);
                /* channel idle? */
                if (!(cc->rcard[ch])) {
                    /* Check SI */
                    if (!(si2bit[cmd->parm.setup.si1] & cc->sil[ch])) {
                        spin_unlock_irqrestore(&card->isdnloop_lock, flags);
                        return 3;
                    }
                    /* ch is idle, si and number matches */
                    cc->rcard[ch] = card;
                    cc->rch[ch] = lch;
                    card->rcard[lch] = cc;
                    card->rch[lch] = ch;
                    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
                    return 0;
                } else {
                    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
                    /* num matches, but busy */
                    if (ch == 1)
                        return 1;
                }
            }
        }
        cc = cc->next;
    }
    return 2;
}

/*
 * Depending on D-channel protocol and caller/called, modify
 * phone number.
 *
 * Parameter:
 *   card   = pointer to card struct.
 *   phone  = pointer phone number.
 *   caller = flag: 1 = caller, 0 = called.
 * Return:
 *   pointer to new phone number.
 */
static char *
isdnloop_vstphone(isdnloop_card *card, char *phone, int caller)
{
    int i;
    static char nphone[30];

    if (!card) {
        printk("BUG!!!\n");
        return "";
    }
    switch (card->ptype) {
    case ISDN_PTYPE_EURO:
        if (caller) {
            for (i = 0; i < 2; i++)
                if (!(strcmp(card->s0num[i], phone)))
                    return (phone);
            return (card->s0num[0]);
        }
        return (phone);
        break;
    case ISDN_PTYPE_1TR6:
        if (caller) {
            sprintf(nphone, "%s%c", card->s0num[0], phone[0]);
            return (nphone);
        } else
            return (&phone[strlen(phone) - 1]);
        break;
    }
    return "";
}

/*
 * Parse an ICN-type command string sent to the 'card'.
 * Perform misc. actions depending on the command.
 *
 * Parameter:
 *   card = pointer to card struct.
 */
static void
isdnloop_parse_cmd(isdnloop_card *card)
{
    char *p = card->omsg;
    isdn_ctrl cmd;
    char buf[60];
    isdnloop_stat *s = isdnloop_cmd_table;
    int action = -1;
    int i;
    int ch;

    if ((card->omsg[0] != '0') && (card->omsg[2] != ';')) {
        isdnloop_fake_err(card);
        return;
    }
    ch = card->omsg[1] - '0';
    if ((ch < 0) || (ch > 2)) {
        isdnloop_fake_err(card);
        return;
    }
    p += 3;
    while (s->statstr) {
        if (!strncmp(p, s->statstr, strlen(s->statstr))) {
            action = s->action;
            if (s->command && (ch != 0)) {
                isdnloop_fake_err(card);
                return;
            }
            break;
        }
        s++;
    }
    if (action == -1)
        return;
    switch (action) {
    case 1:
        /* 0x;BCON_R */
        if (card->rcard[ch - 1]) {
            isdnloop_fake(card->rcard[ch - 1], "BCON_I",
                      card->rch[ch - 1] + 1);
            isdnloop_fake(card, "BCON_C", ch);
        }
        break;
    case 17:
        /* 0x;BCON_I */
        if (card->rcard[ch - 1]) {
            isdnloop_fake(card->rcard[ch - 1], "BCON_C",
                      card->rch[ch - 1] + 1);
        }
        break;
    case 2:
        /* 0x;BDIS_R */
        isdnloop_fake(card, "BDIS_C", ch);
        if (card->rcard[ch - 1]) {
            isdnloop_fake(card->rcard[ch - 1], "BDIS_I",
                      card->rch[ch - 1] + 1);
        }
        break;
    case 16:
        /* 0x;DCON_R */
        isdnloop_kill_ctimer(card, ch - 1);
        if (card->rcard[ch - 1]) {
            isdnloop_kill_ctimer(card->rcard[ch - 1], card->rch[ch - 1]);
            isdnloop_fake(card->rcard[ch - 1], "DCON_C",
                      card->rch[ch - 1] + 1);
            isdnloop_fake(card, "DCON_C", ch);
        }
        break;
    case 3:
        /* 0x;DDIS_R */
        isdnloop_kill_ctimer(card, ch - 1);
        if (card->rcard[ch - 1]) {
            isdnloop_kill_ctimer(card->rcard[ch - 1], card->rch[ch - 1]);
            isdnloop_fake(card->rcard[ch - 1], "DDIS_I",
                      card->rch[ch - 1] + 1);
            card->rcard[ch - 1] = NULL;
        }
        isdnloop_fake(card, "DDIS_C", ch);
        break;
    case 4:
        /* 0x;DSCA_Rdd,yy,zz,oo */
        if (card->ptype != ISDN_PTYPE_1TR6) {
            isdnloop_fake_err(card);
            return;
        }
        /* Fall through */
    case 5:
        /* 0x;DCAL_Rdd,yy,zz,oo */
        p += 6;
        switch (isdnloop_try_call(card, p, ch - 1, &cmd)) {
        case 0:
            /* Alerting */
            sprintf(buf, "D%s_I%s,%02d,%02d,%s",
                (action == 4) ? "SCA" : "CAL",
                isdnloop_vstphone(card, cmd.parm.setup.eazmsn, 1),
                cmd.parm.setup.si1,
                cmd.parm.setup.si2,
                isdnloop_vstphone(card->rcard[ch - 1],
                          cmd.parm.setup.phone, 0));
            isdnloop_fake(card->rcard[ch - 1], buf, card->rch[ch - 1] + 1);
            /* Fall through */
        case 3:
            /* si1 does not match, don't alert but start timer */
            isdnloop_start_ctimer(card, ch - 1);
            break;
        case 1:
            /* Remote busy */
            isdnloop_fake(card, "DDIS_I", ch);
            sprintf(buf, "CAU%s", isdnloop_unicause(card, 1, 1));
            isdnloop_fake(card, buf, ch);
            break;
        case 2:
            /* No such user */
            isdnloop_fake(card, "DDIS_I", ch);
            sprintf(buf, "CAU%s", isdnloop_unicause(card, 1, 2));
            isdnloop_fake(card, buf, ch);
            break;
        }
        break;
    case 6:
        /* 0x;EAZC */
        card->eazlist[ch - 1][0] = '\0';
        break;
    case 7:
        /* 0x;EAZ */
        p += 3;
        strcpy(card->eazlist[ch - 1], p);
        break;
    case 8:
        /* 0x;SEEAZ */
        sprintf(buf, "EAZ-LIST: %s", card->eazlist[ch - 1]);
        isdnloop_fake(card, buf, ch + 1);
        break;
    case 9:
        /* 0x;MSN */
        break;
    case 10:
        /* 0x;MSNALL */
        break;
    case 11:
        /* 0x;SETSIL */
        p += 6;
        i = 0;
        while (strchr("0157", *p)) {
            if (i)
                card->sil[ch - 1] |= si2bit[*p - '0'];
            i = (*p++ == '0');
        }
        if (*p)
            isdnloop_fake_err(card);
        break;
    case 12:
        /* 0x;SEESIL */
        sprintf(buf, "SIN-LIST: ");
        p = buf + 10;
        for (i = 0; i < 3; i++)
            if (card->sil[ch - 1] & (1 << i))
                p += sprintf(p, "%02d", bit2si[i]);
        isdnloop_fake(card, buf, ch + 1);
        break;
    case 13:
        /* 0x;SILC */
        card->sil[ch - 1] = 0;
        break;
    case 14:
        /* 00;FV2ON */
        break;
    case 15:
        /* 00;FV2OFF */
        break;
    }
}

/*
 * Put command-strings into the of the 'card'. In reality, execute them
 * right in place by calling isdnloop_parse_cmd(). Also copy every
 * command to the read message ringbuffer, preceding it with a '>'.
 * These mesagges can be read at /dev/isdnctrl.
 *
 * Parameter:
 *   buf  = pointer to command buffer.
 *   len  = length of buffer data.
 *   user = flag: 1 = called form userlevel, 0 called from kernel.
 *   card = pointer to card struct.
 * Return:
 *   number of bytes transferred (currently always equals len).
 */
static int
isdnloop_writecmd(const u_char *buf, int len, int user, isdnloop_card *card)
{
    int xcount = 0;
    int ocount = 1;
    isdn_ctrl cmd;

    while (len) {
        int count = len;
        u_char *p;
        u_char msg[0x100];

        if (count > 255)
            count = 255;
        if (user) {
            if (copy_from_user(msg, buf, count))
                return -EFAULT;
        } else
            memcpy(msg, buf, count);
        isdnloop_putmsg(card, '>');
        for (p = msg; count > 0; count--, p++) {
            len--;
            xcount++;
            isdnloop_putmsg(card, *p);
            card->omsg[card->optr] = *p;
            if (*p == '\n') {
                card->omsg[card->optr] = '\0';
                card->optr = 0;
                isdnloop_parse_cmd(card);
                if (len) {
                    isdnloop_putmsg(card, '>');
                    ocount++;
                }
            } else {
                if (card->optr < 59)
                    card->optr++;
            }
            ocount++;
        }
    }
    cmd.command = ISDN_STAT_STAVAIL;
    cmd.driver = card->myid;
    cmd.arg = ocount;
    card->interface.statcallb(&cmd);
    return xcount;
}

/*
 * Delete card's pending timers, send STOP to linklevel
 */
static void
isdnloop_stopcard(isdnloop_card *card)
{
    unsigned long flags;
    isdn_ctrl cmd;

    spin_lock_irqsave(&card->isdnloop_lock, flags);
    if (card->flags & ISDNLOOP_FLAGS_RUNNING) {
        card->flags &= ~ISDNLOOP_FLAGS_RUNNING;
        del_timer(&card->st_timer);
        del_timer(&card->rb_timer);
        del_timer(&card->c_timer[0]);
        del_timer(&card->c_timer[1]);
        cmd.command = ISDN_STAT_STOP;
        cmd.driver = card->myid;
        card->interface.statcallb(&cmd);
    }
    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
}

/*
 * Stop all cards before unload.
 */
static void
isdnloop_stopallcards(void)
{
    isdnloop_card *p = cards;

    while (p) {
        isdnloop_stopcard(p);
        p = p->next;
    }
}

/*
 * Start a 'card'. Simulate card's boot message and set the phone
 * number(s) of the virtual 'S0-Interface'. Install D-channel
 * poll timer.
 *
 * Parameter:
 *   card  = pointer to card struct.
 *   sdefp = pointer to struct holding ioctl parameters.
 * Return:
 *   0 on success, -E??? otherwise.
 */
static int
isdnloop_start(isdnloop_card *card, isdnloop_sdef *sdefp)
{
    unsigned long flags;
    isdnloop_sdef sdef;
    int i;

    if (card->flags & ISDNLOOP_FLAGS_RUNNING)
        return -EBUSY;
    if (copy_from_user((char *) &sdef, (char *) sdefp, sizeof(sdef)))
        return -EFAULT;
    spin_lock_irqsave(&card->isdnloop_lock, flags);
    switch (sdef.ptype) {
    case ISDN_PTYPE_EURO:
        if (isdnloop_fake(card, "DRV1.23EC-Q.931-CAPI-CNS-BASIS-20.02.96",
                  -1)) {
            spin_unlock_irqrestore(&card->isdnloop_lock, flags);
            return -ENOMEM;
        }
        card->sil[0] = card->sil[1] = 4;
        if (isdnloop_fake(card, "TEI OK", 0)) {
            spin_unlock_irqrestore(&card->isdnloop_lock, flags);
            return -ENOMEM;
        }
        for (i = 0; i < 3; i++)
            strcpy(card->s0num[i], sdef.num[i]);
        break;
    case ISDN_PTYPE_1TR6:
        if (isdnloop_fake(card, "DRV1.04TC-1TR6-CAPI-CNS-BASIS-29.11.95",
                  -1)) {
            spin_unlock_irqrestore(&card->isdnloop_lock, flags);
            return -ENOMEM;
        }
        card->sil[0] = card->sil[1] = 4;
        if (isdnloop_fake(card, "TEI OK", 0)) {
            spin_unlock_irqrestore(&card->isdnloop_lock, flags);
            return -ENOMEM;
        }
        strcpy(card->s0num[0], sdef.num[0]);
        card->s0num[1][0] = '\0';
        card->s0num[2][0] = '\0';
        break;
    default:
        spin_unlock_irqrestore(&card->isdnloop_lock, flags);
        printk(KERN_WARNING "isdnloop: Illegal D-channel protocol %d\n",
               sdef.ptype);
        return -EINVAL;
    }
    init_timer(&card->st_timer);
    card->st_timer.expires = jiffies + ISDNLOOP_TIMER_DCREAD;
    card->st_timer.function = isdnloop_polldchan;
    card->st_timer.data = (unsigned long) card;
    add_timer(&card->st_timer);
    card->flags |= ISDNLOOP_FLAGS_RUNNING;
    spin_unlock_irqrestore(&card->isdnloop_lock, flags);
    return 0;
}

/*
 * Main handler for commands sent by linklevel.
 */
static int
isdnloop_command(isdn_ctrl *c, isdnloop_card *card)
{
    ulong a;
    int i;
    char cbuf[60];
    isdn_ctrl cmd;
    isdnloop_cdef cdef;

    switch (c->command) {
    case ISDN_CMD_IOCTL:
        memcpy(&a, c->parm.num, sizeof(ulong));
        switch (c->arg) {
        case ISDNLOOP_IOCTL_DEBUGVAR:
            return (ulong) card;
        case ISDNLOOP_IOCTL_STARTUP:
            if (!access_ok(VERIFY_READ, (void *) a, sizeof(isdnloop_sdef)))
                return -EFAULT;
            return (isdnloop_start(card, (isdnloop_sdef *) a));
            break;
        case ISDNLOOP_IOCTL_ADDCARD:
            if (copy_from_user((char *)&cdef,
                       (char *)a,
                       sizeof(cdef)))
                return -EFAULT;
            return (isdnloop_addcard(cdef.id1));
            break;
        case ISDNLOOP_IOCTL_LEASEDCFG:
            if (a) {
                if (!card->leased) {
                    card->leased = 1;
                    while (card->ptype == ISDN_PTYPE_UNKNOWN)
                        schedule_timeout_interruptible(10);
                    schedule_timeout_interruptible(10);
                    sprintf(cbuf, "00;FV2ON\n01;EAZ1\n02;EAZ2\n");
                    i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
                    printk(KERN_INFO
                           "isdnloop: (%s) Leased-line mode enabled\n",
                           CID);
                    cmd.command = ISDN_STAT_RUN;
                    cmd.driver = card->myid;
                    cmd.arg = 0;
                    card->interface.statcallb(&cmd);
                }
            } else {
                if (card->leased) {
                    card->leased = 0;
                    sprintf(cbuf, "00;FV2OFF\n");
                    i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
                    printk(KERN_INFO
                           "isdnloop: (%s) Leased-line mode disabled\n",
                           CID);
                    cmd.command = ISDN_STAT_RUN;
                    cmd.driver = card->myid;
                    cmd.arg = 0;
                    card->interface.statcallb(&cmd);
                }
            }
            return 0;
        default:
            return -EINVAL;
        }
        break;
    case ISDN_CMD_DIAL:
        if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
            return -ENODEV;
        if (card->leased)
            break;
        if ((c->arg & 255) < ISDNLOOP_BCH) {
            char *p;
            char dial[50];
            char dcode[4];

            a = c->arg;
            p = c->parm.setup.phone;
            if (*p == 's' || *p == 'S') {
                /* Dial for SPV */
                p++;
                strcpy(dcode, "SCA");
            } else
                /* Normal Dial */
                strcpy(dcode, "CAL");
            strcpy(dial, p);
            sprintf(cbuf, "%02d;D%s_R%s,%02d,%02d,%s\n", (int) (a + 1),
                dcode, dial, c->parm.setup.si1,
                c->parm.setup.si2, c->parm.setup.eazmsn);
            i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
        }
        break;
    case ISDN_CMD_ACCEPTD:
        if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
            return -ENODEV;
        if (c->arg < ISDNLOOP_BCH) {
            a = c->arg + 1;
            cbuf[0] = 0;
            switch (card->l2_proto[a - 1]) {
            case ISDN_PROTO_L2_X75I:
                sprintf(cbuf, "%02d;BX75\n", (int) a);
                break;
#ifdef CONFIG_ISDN_X25
            case ISDN_PROTO_L2_X25DTE:
                sprintf(cbuf, "%02d;BX2T\n", (int) a);
                break;
            case ISDN_PROTO_L2_X25DCE:
                sprintf(cbuf, "%02d;BX2C\n", (int) a);
                break;
#endif
            case ISDN_PROTO_L2_HDLC:
                sprintf(cbuf, "%02d;BTRA\n", (int) a);
                break;
            }
            if (strlen(cbuf))
                i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
            sprintf(cbuf, "%02d;DCON_R\n", (int) a);
            i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
        }
        break;
    case ISDN_CMD_ACCEPTB:
        if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
            return -ENODEV;
        if (c->arg < ISDNLOOP_BCH) {
            a = c->arg + 1;
            switch (card->l2_proto[a - 1]) {
            case ISDN_PROTO_L2_X75I:
                sprintf(cbuf, "%02d;BCON_R,BX75\n", (int) a);
                break;
#ifdef CONFIG_ISDN_X25
            case ISDN_PROTO_L2_X25DTE:
                sprintf(cbuf, "%02d;BCON_R,BX2T\n", (int) a);
                break;
            case ISDN_PROTO_L2_X25DCE:
                sprintf(cbuf, "%02d;BCON_R,BX2C\n", (int) a);
                break;
#endif
            case ISDN_PROTO_L2_HDLC:
                sprintf(cbuf, "%02d;BCON_R,BTRA\n", (int) a);
                break;
            default:
                sprintf(cbuf, "%02d;BCON_R\n", (int) a);
            }
            printk(KERN_DEBUG "isdnloop writecmd '%s'\n", cbuf);
            i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
            break;
        case ISDN_CMD_HANGUP:
            if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
                return -ENODEV;
            if (c->arg < ISDNLOOP_BCH) {
                a = c->arg + 1;
                sprintf(cbuf, "%02d;BDIS_R\n%02d;DDIS_R\n", (int) a, (int) a);
                i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
            }
            break;
        case ISDN_CMD_SETEAZ:
            if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
                return -ENODEV;
            if (card->leased)
                break;
            if (c->arg < ISDNLOOP_BCH) {
                a = c->arg + 1;
                if (card->ptype == ISDN_PTYPE_EURO) {
                    sprintf(cbuf, "%02d;MS%s%s\n", (int) a,
                        c->parm.num[0] ? "N" : "ALL", c->parm.num);
                } else
                    sprintf(cbuf, "%02d;EAZ%s\n", (int) a,
                        c->parm.num[0] ? c->parm.num : (u_char *) "0123456789");
                i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
            }
            break;
        case ISDN_CMD_CLREAZ:
            if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
                return -ENODEV;
            if (card->leased)
                break;
            if (c->arg < ISDNLOOP_BCH) {
                a = c->arg + 1;
                if (card->ptype == ISDN_PTYPE_EURO)
                    sprintf(cbuf, "%02d;MSNC\n", (int) a);
                else
                    sprintf(cbuf, "%02d;EAZC\n", (int) a);
                i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
            }
            break;
        case ISDN_CMD_SETL2:
            if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
                return -ENODEV;
            if ((c->arg & 255) < ISDNLOOP_BCH) {
                a = c->arg;
                switch (a >> 8) {
                case ISDN_PROTO_L2_X75I:
                    sprintf(cbuf, "%02d;BX75\n", (int) (a & 255) + 1);
                    break;
#ifdef CONFIG_ISDN_X25
                case ISDN_PROTO_L2_X25DTE:
                    sprintf(cbuf, "%02d;BX2T\n", (int) (a & 255) + 1);
                    break;
                case ISDN_PROTO_L2_X25DCE:
                    sprintf(cbuf, "%02d;BX2C\n", (int) (a & 255) + 1);
                    break;
#endif
                case ISDN_PROTO_L2_HDLC:
                    sprintf(cbuf, "%02d;BTRA\n", (int) (a & 255) + 1);
                    break;
                case ISDN_PROTO_L2_TRANS:
                    sprintf(cbuf, "%02d;BTRA\n", (int) (a & 255) + 1);
                    break;
                default:
                    return -EINVAL;
                }
                i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card);
                card->l2_proto[a & 255] = (a >> 8);
            }
            break;
        case ISDN_CMD_SETL3:
            if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
                return -ENODEV;
            return 0;
        default:
            return -EINVAL;
        }
    }
    return 0;
}

/*
 * Find card with given driverId
 */
static inline isdnloop_card *
isdnloop_findcard(int driverid)
{
    isdnloop_card *p = cards;

    while (p) {
        if (p->myid == driverid)
            return p;
        p = p->next;
    }
    return (isdnloop_card *) 0;
}

/*
 * Wrapper functions for interface to linklevel
 */
static int
if_command(isdn_ctrl *c)
{
    isdnloop_card *card = isdnloop_findcard(c->driver);

    if (card)
        return (isdnloop_command(c, card));
    printk(KERN_ERR
           "isdnloop: if_command called with invalid driverId!\n");
    return -ENODEV;
}

static int
if_writecmd(const u_char __user *buf, int len, int id, int channel)
{
    isdnloop_card *card = isdnloop_findcard(id);

    if (card) {
        if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
            return -ENODEV;
        return (isdnloop_writecmd(buf, len, 1, card));
    }
    printk(KERN_ERR
           "isdnloop: if_writecmd called with invalid driverId!\n");
    return -ENODEV;
}

static int
if_readstatus(u_char __user *buf, int len, int id, int channel)
{
    isdnloop_card *card = isdnloop_findcard(id);

    if (card) {
        if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
            return -ENODEV;
        return (isdnloop_readstatus(buf, len, card));
    }
    printk(KERN_ERR
           "isdnloop: if_readstatus called with invalid driverId!\n");
    return -ENODEV;
}

static int
if_sendbuf(int id, int channel, int ack, struct sk_buff *skb)
{
    isdnloop_card *card = isdnloop_findcard(id);

    if (card) {
        if (!(card->flags & ISDNLOOP_FLAGS_RUNNING))
            return -ENODEV;
        /* ack request stored in skb scratch area */
        *(skb->head) = ack;
        return (isdnloop_sendbuf(channel, skb, card));
    }
    printk(KERN_ERR
           "isdnloop: if_sendbuf called with invalid driverId!\n");
    return -ENODEV;
}

/*
 * Allocate a new card-struct, initialize it
 * link it into cards-list and register it at linklevel.
 */
static isdnloop_card *
isdnloop_initcard(char *id)
{
    isdnloop_card *card;
    int i;

    if (!(card = kzalloc(sizeof(isdnloop_card), GFP_KERNEL))) {
        printk(KERN_WARNING
               "isdnloop: (%s) Could not allocate card-struct.\n", id);
        return (isdnloop_card *) 0;
    }
    card->interface.owner = THIS_MODULE;
    card->interface.channels = ISDNLOOP_BCH;
    card->interface.hl_hdrlen  = 1; /* scratch area for storing ack flag*/
    card->interface.maxbufsize = 4000;
    card->interface.command = if_command;
    card->interface.writebuf_skb = if_sendbuf;
    card->interface.writecmd = if_writecmd;
    card->interface.readstat = if_readstatus;
    card->interface.features = ISDN_FEATURE_L2_X75I |
#ifdef CONFIG_ISDN_X25
        ISDN_FEATURE_L2_X25DTE |
        ISDN_FEATURE_L2_X25DCE |
#endif
        ISDN_FEATURE_L2_HDLC |
        ISDN_FEATURE_L3_TRANS |
        ISDN_FEATURE_P_UNKNOWN;
    card->ptype = ISDN_PTYPE_UNKNOWN;
    strlcpy(card->interface.id, id, sizeof(card->interface.id));
    card->msg_buf_write = card->msg_buf;
    card->msg_buf_read = card->msg_buf;
    card->msg_buf_end = &card->msg_buf[sizeof(card->msg_buf) - 1];
    for (i = 0; i < ISDNLOOP_BCH; i++) {
        card->l2_proto[i] = ISDN_PROTO_L2_X75I;
        skb_queue_head_init(&card->bqueue[i]);
    }
    skb_queue_head_init(&card->dqueue);
    spin_lock_init(&card->isdnloop_lock);
    card->next = cards;
    cards = card;
    if (!register_isdn(&card->interface)) {
        cards = cards->next;
        printk(KERN_WARNING
               "isdnloop: Unable to register %s\n", id);
        kfree(card);
        return (isdnloop_card *) 0;
    }
    card->myid = card->interface.channels;
    return card;
}

static int
isdnloop_addcard(char *id1)
{
    isdnloop_card *card;

    if (!(card = isdnloop_initcard(id1))) {
        return -EIO;
    }
    printk(KERN_INFO
           "isdnloop: (%s) virtual card added\n",
           card->interface.id);
    return 0;
}

static int __init
isdnloop_init(void)
{
    if (isdnloop_id)
        return (isdnloop_addcard(isdnloop_id));

    return 0;
}

static void __exit
isdnloop_exit(void)
{
    isdn_ctrl cmd;
    isdnloop_card *card = cards;
    isdnloop_card *last;
    int i;

    isdnloop_stopallcards();
    while (card) {
        cmd.command = ISDN_STAT_UNLOAD;
        cmd.driver = card->myid;
        card->interface.statcallb(&cmd);
        for (i = 0; i < ISDNLOOP_BCH; i++)
            isdnloop_free_queue(card, i);
        card = card->next;
    }
    card = cards;
    while (card) {
        last = card;
        skb_queue_purge(&card->dqueue);
        card = card->next;
        kfree(last);
    }
    printk(KERN_NOTICE "isdnloop-ISDN-driver unloaded\n");
}

module_init(isdnloop_init);
module_exit(isdnloop_exit);