isdnl2.c

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/* $Id: isdnl2.c,v 2.30.2.4 2004/02/11 13:21:34 keil Exp $
 *
 * Author       Karsten Keil
 *              based on the teles driver from Jan den Ouden
 * Copyright    by Karsten Keil      <[email protected]>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 * For changes and modifications please read
 * Documentation/isdn/HiSax.cert
 *
 * Thanks to    Jan den Ouden
 *              Fritz Elfert
 *
 */

#include <linux/init.h>
#include <linux/gfp.h>
#include "hisax.h"
#include "isdnl2.h"

const char *l2_revision = "$Revision: 2.30.2.4 $";

static void l2m_debug(struct FsmInst *fi, char *fmt, ...);

static struct Fsm l2fsm;

enum {
    ST_L2_1,
    ST_L2_2,
    ST_L2_3,
    ST_L2_4,
    ST_L2_5,
    ST_L2_6,
    ST_L2_7,
    ST_L2_8,
};

#define L2_STATE_COUNT (ST_L2_8 + 1)

static char *strL2State[] =
{
    "ST_L2_1",
    "ST_L2_2",
    "ST_L2_3",
    "ST_L2_4",
    "ST_L2_5",
    "ST_L2_6",
    "ST_L2_7",
    "ST_L2_8",
};

enum {
    EV_L2_UI,
    EV_L2_SABME,
    EV_L2_DISC,
    EV_L2_DM,
    EV_L2_UA,
    EV_L2_FRMR,
    EV_L2_SUPER,
    EV_L2_I,
    EV_L2_DL_DATA,
    EV_L2_ACK_PULL,
    EV_L2_DL_UNIT_DATA,
    EV_L2_DL_ESTABLISH_REQ,
    EV_L2_DL_RELEASE_REQ,
    EV_L2_MDL_ASSIGN,
    EV_L2_MDL_REMOVE,
    EV_L2_MDL_ERROR,
    EV_L1_DEACTIVATE,
    EV_L2_T200,
    EV_L2_T203,
    EV_L2_SET_OWN_BUSY,
    EV_L2_CLEAR_OWN_BUSY,
    EV_L2_FRAME_ERROR,
};

#define L2_EVENT_COUNT (EV_L2_FRAME_ERROR + 1)

static char *strL2Event[] =
{
    "EV_L2_UI",
    "EV_L2_SABME",
    "EV_L2_DISC",
    "EV_L2_DM",
    "EV_L2_UA",
    "EV_L2_FRMR",
    "EV_L2_SUPER",
    "EV_L2_I",
    "EV_L2_DL_DATA",
    "EV_L2_ACK_PULL",
    "EV_L2_DL_UNIT_DATA",
    "EV_L2_DL_ESTABLISH_REQ",
    "EV_L2_DL_RELEASE_REQ",
    "EV_L2_MDL_ASSIGN",
    "EV_L2_MDL_REMOVE",
    "EV_L2_MDL_ERROR",
    "EV_L1_DEACTIVATE",
    "EV_L2_T200",
    "EV_L2_T203",
    "EV_L2_SET_OWN_BUSY",
    "EV_L2_CLEAR_OWN_BUSY",
    "EV_L2_FRAME_ERROR",
};

static int l2addrsize(struct Layer2 *l2);

static void
set_peer_busy(struct Layer2 *l2) {
    test_and_set_bit(FLG_PEER_BUSY, &l2->flag);
    if (!skb_queue_empty(&l2->i_queue) ||
        !skb_queue_empty(&l2->ui_queue))
        test_and_set_bit(FLG_L2BLOCK, &l2->flag);
}

static void
clear_peer_busy(struct Layer2 *l2) {
    if (test_and_clear_bit(FLG_PEER_BUSY, &l2->flag))
        test_and_clear_bit(FLG_L2BLOCK, &l2->flag);
}

static void
InitWin(struct Layer2 *l2)
{
    int i;

    for (i = 0; i < MAX_WINDOW; i++)
        l2->windowar[i] = NULL;
}

static int
freewin1(struct Layer2 *l2)
{
    int i, cnt = 0;

    for (i = 0; i < MAX_WINDOW; i++) {
        if (l2->windowar[i]) {
            cnt++;
            dev_kfree_skb(l2->windowar[i]);
            l2->windowar[i] = NULL;
        }
    }
    return cnt;
}

static inline void
freewin(struct PStack *st)
{
    freewin1(&st->l2);
}

static void
ReleaseWin(struct Layer2 *l2)
{
    int cnt;

    if ((cnt = freewin1(l2)))
        printk(KERN_WARNING "isdl2 freed %d skbuffs in release\n", cnt);
}

static inline unsigned int
cansend(struct PStack *st)
{
    unsigned int p1;

    if (test_bit(FLG_MOD128, &st->l2.flag))
        p1 = (st->l2.vs - st->l2.va) % 128;
    else
        p1 = (st->l2.vs - st->l2.va) % 8;
    return ((p1 < st->l2.window) && !test_bit(FLG_PEER_BUSY, &st->l2.flag));
}

static inline void
clear_exception(struct Layer2 *l2)
{
    test_and_clear_bit(FLG_ACK_PEND, &l2->flag);
    test_and_clear_bit(FLG_REJEXC, &l2->flag);
    test_and_clear_bit(FLG_OWN_BUSY, &l2->flag);
    clear_peer_busy(l2);
}

static inline int
l2headersize(struct Layer2 *l2, int ui)
{
    return (((test_bit(FLG_MOD128, &l2->flag) && (!ui)) ? 2 : 1) +
        (test_bit(FLG_LAPD, &l2->flag) ? 2 : 1));
}

inline int
l2addrsize(struct Layer2 *l2)
{
    return (test_bit(FLG_LAPD, &l2->flag) ? 2 : 1);
}

static int
sethdraddr(struct Layer2 *l2, u_char *header, int rsp)
{
    u_char *ptr = header;
    int crbit = rsp;

    if (test_bit(FLG_LAPD, &l2->flag)) {
        *ptr++ = (l2->sap << 2) | (rsp ? 2 : 0);
        *ptr++ = (l2->tei << 1) | 1;
        return (2);
    } else {
        if (test_bit(FLG_ORIG, &l2->flag))
            crbit = !crbit;
        if (crbit)
            *ptr++ = 1;
        else
            *ptr++ = 3;
        return (1);
    }
}

static inline void
enqueue_super(struct PStack *st,
          struct sk_buff *skb)
{
    if (test_bit(FLG_LAPB, &st->l2.flag))
        st->l1.bcs->tx_cnt += skb->len;
    st->l2.l2l1(st, PH_DATA | REQUEST, skb);
}

#define enqueue_ui(a, b) enqueue_super(a, b)

static inline int
IsUI(u_char *data)
{
    return ((data[0] & 0xef) == UI);
}

static inline int
IsUA(u_char *data)
{
    return ((data[0] & 0xef) == UA);
}

static inline int
IsDM(u_char *data)
{
    return ((data[0] & 0xef) == DM);
}

static inline int
IsDISC(u_char *data)
{
    return ((data[0] & 0xef) == DISC);
}

static inline int
IsSFrame(u_char *data, struct PStack *st)
{
    register u_char d = *data;

    if (!test_bit(FLG_MOD128, &st->l2.flag))
        d &= 0xf;
    return (((d & 0xf3) == 1) && ((d & 0x0c) != 0x0c));
}

static inline int
IsSABME(u_char *data, struct PStack *st)
{
    u_char d = data[0] & ~0x10;

    return (test_bit(FLG_MOD128, &st->l2.flag) ? d == SABME : d == SABM);
}

static inline int
IsREJ(u_char *data, struct PStack *st)
{
    return (test_bit(FLG_MOD128, &st->l2.flag) ? data[0] == REJ : (data[0] & 0xf) == REJ);
}

static inline int
IsFRMR(u_char *data)
{
    return ((data[0] & 0xef) == FRMR);
}

static inline int
IsRNR(u_char *data, struct PStack *st)
{
    return (test_bit(FLG_MOD128, &st->l2.flag) ? data[0] == RNR : (data[0] & 0xf) == RNR);
}

static int
iframe_error(struct PStack *st, struct sk_buff *skb)
{
    int i = l2addrsize(&st->l2) + (test_bit(FLG_MOD128, &st->l2.flag) ? 2 : 1);
    int rsp = *skb->data & 0x2;

    if (test_bit(FLG_ORIG, &st->l2.flag))
        rsp = !rsp;

    if (rsp)
        return 'L';


    if (skb->len < i)
        return 'N';

    if ((skb->len - i) > st->l2.maxlen)
        return 'O';


    return 0;
}

static int
super_error(struct PStack *st, struct sk_buff *skb)
{
    if (skb->len != l2addrsize(&st->l2) +
        (test_bit(FLG_MOD128, &st->l2.flag) ? 2 : 1))
        return 'N';

    return 0;
}

static int
unnum_error(struct PStack *st, struct sk_buff *skb, int wantrsp)
{
    int rsp = (*skb->data & 0x2) >> 1;
    if (test_bit(FLG_ORIG, &st->l2.flag))
        rsp = !rsp;

    if (rsp != wantrsp)
        return 'L';

    if (skb->len != l2addrsize(&st->l2) + 1)
        return 'N';

    return 0;
}

static int
UI_error(struct PStack *st, struct sk_buff *skb)
{
    int rsp = *skb->data & 0x2;
    if (test_bit(FLG_ORIG, &st->l2.flag))
        rsp = !rsp;

    if (rsp)
        return 'L';

    if (skb->len > st->l2.maxlen + l2addrsize(&st->l2) + 1)
        return 'O';

    return 0;
}

static int
FRMR_error(struct PStack *st, struct sk_buff *skb)
{
    int headers = l2addrsize(&st->l2) + 1;
    u_char *datap = skb->data + headers;
    int rsp = *skb->data & 0x2;

    if (test_bit(FLG_ORIG, &st->l2.flag))
        rsp = !rsp;

    if (!rsp)
        return 'L';

    if (test_bit(FLG_MOD128, &st->l2.flag)) {
        if (skb->len < headers + 5)
            return 'N';
        else
            l2m_debug(&st->l2.l2m, "FRMR information %2x %2x %2x %2x %2x",
                  datap[0], datap[1], datap[2],
                  datap[3], datap[4]);
    } else {
        if (skb->len < headers + 3)
            return 'N';
        else
            l2m_debug(&st->l2.l2m, "FRMR information %2x %2x %2x",
                  datap[0], datap[1], datap[2]);
    }

    return 0;
}

static unsigned int
legalnr(struct PStack *st, unsigned int nr)
{
    struct Layer2 *l2 = &st->l2;

    if (test_bit(FLG_MOD128, &l2->flag))
        return ((nr - l2->va) % 128) <= ((l2->vs - l2->va) % 128);
    else
        return ((nr - l2->va) % 8) <= ((l2->vs - l2->va) % 8);
}

static void
setva(struct PStack *st, unsigned int nr)
{
    struct Layer2 *l2 = &st->l2;
    int len;
    u_long flags;

    spin_lock_irqsave(&l2->lock, flags);
    while (l2->va != nr) {
        (l2->va)++;
        if (test_bit(FLG_MOD128, &l2->flag))
            l2->va %= 128;
        else
            l2->va %= 8;
        len = l2->windowar[l2->sow]->len;
        if (PACKET_NOACK == l2->windowar[l2->sow]->pkt_type)
            len = -1;
        dev_kfree_skb(l2->windowar[l2->sow]);
        l2->windowar[l2->sow] = NULL;
        l2->sow = (l2->sow + 1) % l2->window;
        spin_unlock_irqrestore(&l2->lock, flags);
        if (test_bit(FLG_LLI_L2WAKEUP, &st->lli.flag) && (len >= 0))
            lli_writewakeup(st, len);
        spin_lock_irqsave(&l2->lock, flags);
    }
    spin_unlock_irqrestore(&l2->lock, flags);
}

static void
send_uframe(struct PStack *st, u_char cmd, u_char cr)
{
    struct sk_buff *skb;
    u_char tmp[MAX_HEADER_LEN];
    int i;

    i = sethdraddr(&st->l2, tmp, cr);
    tmp[i++] = cmd;
    if (!(skb = alloc_skb(i, GFP_ATOMIC))) {
        printk(KERN_WARNING "isdl2 can't alloc sbbuff for send_uframe\n");
        return;
    }
    memcpy(skb_put(skb, i), tmp, i);
    enqueue_super(st, skb);
}

static inline u_char
get_PollFlag(struct PStack *st, struct sk_buff *skb)
{
    return (skb->data[l2addrsize(&(st->l2))] & 0x10);
}

static inline u_char
get_PollFlagFree(struct PStack *st, struct sk_buff *skb)
{
    u_char PF;

    PF = get_PollFlag(st, skb);
    dev_kfree_skb(skb);
    return (PF);
}

static inline void
start_t200(struct PStack *st, int i)
{
    FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, i);
    test_and_set_bit(FLG_T200_RUN, &st->l2.flag);
}

static inline void
restart_t200(struct PStack *st, int i)
{
    FsmRestartTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, i);
    test_and_set_bit(FLG_T200_RUN, &st->l2.flag);
}

static inline void
stop_t200(struct PStack *st, int i)
{
    if (test_and_clear_bit(FLG_T200_RUN, &st->l2.flag))
        FsmDelTimer(&st->l2.t200, i);
}

static inline void
st5_dl_release_l2l3(struct PStack *st)
{
    int pr;

    if (test_and_clear_bit(FLG_PEND_REL, &st->l2.flag))
        pr = DL_RELEASE | CONFIRM;
    else
        pr = DL_RELEASE | INDICATION;

    st->l2.l2l3(st, pr, NULL);
}

static inline void
lapb_dl_release_l2l3(struct PStack *st, int f)
{
    if (test_bit(FLG_LAPB, &st->l2.flag))
        st->l2.l2l1(st, PH_DEACTIVATE | REQUEST, NULL);
    st->l2.l2l3(st, DL_RELEASE | f, NULL);
}

static void
establishlink(struct FsmInst *fi)
{
    struct PStack *st = fi->userdata;
    u_char cmd;

    clear_exception(&st->l2);
    st->l2.rc = 0;
    cmd = (test_bit(FLG_MOD128, &st->l2.flag) ? SABME : SABM) | 0x10;
    send_uframe(st, cmd, CMD);
    FsmDelTimer(&st->l2.t203, 1);
    restart_t200(st, 1);
    test_and_clear_bit(FLG_PEND_REL, &st->l2.flag);
    freewin(st);
    FsmChangeState(fi, ST_L2_5);
}

static void
l2_mdl_error_ua(struct FsmInst *fi, int event, void *arg)
{
    struct sk_buff *skb = arg;
    struct PStack *st = fi->userdata;

    if (get_PollFlagFree(st, skb))
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'C');
    else
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'D');
}

static void
l2_mdl_error_dm(struct FsmInst *fi, int event, void *arg)
{
    struct sk_buff *skb = arg;
    struct PStack *st = fi->userdata;

    if (get_PollFlagFree(st, skb))
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'B');
    else {
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'E');
        establishlink(fi);
        test_and_clear_bit(FLG_L3_INIT, &st->l2.flag);
    }
}

static void
l2_st8_mdl_error_dm(struct FsmInst *fi, int event, void *arg)
{
    struct sk_buff *skb = arg;
    struct PStack *st = fi->userdata;

    if (get_PollFlagFree(st, skb))
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'B');
    else {
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'E');
    }
    establishlink(fi);
    test_and_clear_bit(FLG_L3_INIT, &st->l2.flag);
}

static void
l2_go_st3(struct FsmInst *fi, int event, void *arg)
{
    FsmChangeState(fi, ST_L2_3);
}

static void
l2_mdl_assign(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    FsmChangeState(fi, ST_L2_3);
    st->l2.l2tei(st, MDL_ASSIGN | INDICATION, NULL);
}

static void
l2_queue_ui_assign(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    skb_queue_tail(&st->l2.ui_queue, skb);
    FsmChangeState(fi, ST_L2_2);
    st->l2.l2tei(st, MDL_ASSIGN | INDICATION, NULL);
}

static void
l2_queue_ui(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    skb_queue_tail(&st->l2.ui_queue, skb);
}

static void
tx_ui(struct PStack *st)
{
    struct sk_buff *skb;
    u_char header[MAX_HEADER_LEN];
    int i;

    i = sethdraddr(&(st->l2), header, CMD);
    header[i++] = UI;
    while ((skb = skb_dequeue(&st->l2.ui_queue))) {
        memcpy(skb_push(skb, i), header, i);
        enqueue_ui(st, skb);
    }
}

static void
l2_send_ui(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    skb_queue_tail(&st->l2.ui_queue, skb);
    tx_ui(st);
}

static void
l2_got_ui(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    skb_pull(skb, l2headersize(&st->l2, 1));
    st->l2.l2l3(st, DL_UNIT_DATA | INDICATION, skb);
/*  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 *      in states 1-3 for broadcast
 */


}

static void
l2_establish(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    establishlink(fi);
    test_and_set_bit(FLG_L3_INIT, &st->l2.flag);
}

static void
l2_discard_i_setl3(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    test_and_set_bit(FLG_L3_INIT, &st->l2.flag);
    test_and_clear_bit(FLG_PEND_REL, &st->l2.flag);
}

static void
l2_l3_reestablish(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    establishlink(fi);
    test_and_set_bit(FLG_L3_INIT, &st->l2.flag);
}

static void
l2_release(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    st->l2.l2l3(st, DL_RELEASE | CONFIRM, NULL);
}

static void
l2_pend_rel(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    test_and_set_bit(FLG_PEND_REL, &st->l2.flag);
}

static void
l2_disconnect(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    freewin(st);
    FsmChangeState(fi, ST_L2_6);
    st->l2.rc = 0;
    send_uframe(st, DISC | 0x10, CMD);
    FsmDelTimer(&st->l2.t203, 1);
    restart_t200(st, 2);
}

static void
l2_start_multi(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    send_uframe(st, UA | get_PollFlagFree(st, skb), RSP);

    clear_exception(&st->l2);
    st->l2.vs = 0;
    st->l2.va = 0;
    st->l2.vr = 0;
    st->l2.sow = 0;
    FsmChangeState(fi, ST_L2_7);
    FsmAddTimer(&st->l2.t203, st->l2.T203, EV_L2_T203, NULL, 3);

    st->l2.l2l3(st, DL_ESTABLISH | INDICATION, NULL);
}

static void
l2_send_UA(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    send_uframe(st, UA | get_PollFlagFree(st, skb), RSP);
}

static void
l2_send_DM(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    send_uframe(st, DM | get_PollFlagFree(st, skb), RSP);
}

static void
l2_restart_multi(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;
    int est = 0, state;

    state = fi->state;

    send_uframe(st, UA | get_PollFlagFree(st, skb), RSP);

    st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'F');

    if (st->l2.vs != st->l2.va) {
        skb_queue_purge(&st->l2.i_queue);
        est = 1;
    }

    clear_exception(&st->l2);
    st->l2.vs = 0;
    st->l2.va = 0;
    st->l2.vr = 0;
    st->l2.sow = 0;
    FsmChangeState(fi, ST_L2_7);
    stop_t200(st, 3);
    FsmRestartTimer(&st->l2.t203, st->l2.T203, EV_L2_T203, NULL, 3);

    if (est)
        st->l2.l2l3(st, DL_ESTABLISH | INDICATION, NULL);

    if ((ST_L2_7 == state) || (ST_L2_8 == state))
        if (!skb_queue_empty(&st->l2.i_queue) && cansend(st))
            st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
}

static void
l2_stop_multi(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    FsmChangeState(fi, ST_L2_4);
    FsmDelTimer(&st->l2.t203, 3);
    stop_t200(st, 4);

    send_uframe(st, UA | get_PollFlagFree(st, skb), RSP);

    skb_queue_purge(&st->l2.i_queue);
    freewin(st);
    lapb_dl_release_l2l3(st, INDICATION);
}

static void
l2_connected(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;
    int pr = -1;

    if (!get_PollFlag(st, skb)) {
        l2_mdl_error_ua(fi, event, arg);
        return;
    }
    dev_kfree_skb(skb);

    if (test_and_clear_bit(FLG_PEND_REL, &st->l2.flag))
        l2_disconnect(fi, event, arg);

    if (test_and_clear_bit(FLG_L3_INIT, &st->l2.flag)) {
        pr = DL_ESTABLISH | CONFIRM;
    } else if (st->l2.vs != st->l2.va) {
        skb_queue_purge(&st->l2.i_queue);
        pr = DL_ESTABLISH | INDICATION;
    }

    stop_t200(st, 5);

    st->l2.vr = 0;
    st->l2.vs = 0;
    st->l2.va = 0;
    st->l2.sow = 0;
    FsmChangeState(fi, ST_L2_7);
    FsmAddTimer(&st->l2.t203, st->l2.T203, EV_L2_T203, NULL, 4);

    if (pr != -1)
        st->l2.l2l3(st, pr, NULL);

    if (!skb_queue_empty(&st->l2.i_queue) && cansend(st))
        st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
}

static void
l2_released(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    if (!get_PollFlag(st, skb)) {
        l2_mdl_error_ua(fi, event, arg);
        return;
    }
    dev_kfree_skb(skb);

    stop_t200(st, 6);
    lapb_dl_release_l2l3(st, CONFIRM);
    FsmChangeState(fi, ST_L2_4);
}

static void
l2_reestablish(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    if (!get_PollFlagFree(st, skb)) {
        establishlink(fi);
        test_and_set_bit(FLG_L3_INIT, &st->l2.flag);
    }
}

static void
l2_st5_dm_release(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    if (get_PollFlagFree(st, skb)) {
        stop_t200(st, 7);
        if (!test_bit(FLG_L3_INIT, &st->l2.flag))
            skb_queue_purge(&st->l2.i_queue);
        if (test_bit(FLG_LAPB, &st->l2.flag))
            st->l2.l2l1(st, PH_DEACTIVATE | REQUEST, NULL);
        st5_dl_release_l2l3(st);
        FsmChangeState(fi, ST_L2_4);
    }
}

static void
l2_st6_dm_release(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    if (get_PollFlagFree(st, skb)) {
        stop_t200(st, 8);
        lapb_dl_release_l2l3(st, CONFIRM);
        FsmChangeState(fi, ST_L2_4);
    }
}

static inline void
enquiry_cr(struct PStack *st, u_char typ, u_char cr, u_char pf)
{
    struct sk_buff *skb;
    struct Layer2 *l2;
    u_char tmp[MAX_HEADER_LEN];
    int i;

    l2 = &st->l2;
    i = sethdraddr(l2, tmp, cr);
    if (test_bit(FLG_MOD128, &l2->flag)) {
        tmp[i++] = typ;
        tmp[i++] = (l2->vr << 1) | (pf ? 1 : 0);
    } else
        tmp[i++] = (l2->vr << 5) | typ | (pf ? 0x10 : 0);
    if (!(skb = alloc_skb(i, GFP_ATOMIC))) {
        printk(KERN_WARNING "isdl2 can't alloc sbbuff for enquiry_cr\n");
        return;
    }
    memcpy(skb_put(skb, i), tmp, i);
    enqueue_super(st, skb);
}

static inline void
enquiry_response(struct PStack *st)
{
    if (test_bit(FLG_OWN_BUSY, &st->l2.flag))
        enquiry_cr(st, RNR, RSP, 1);
    else
        enquiry_cr(st, RR, RSP, 1);
    test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag);
}

static inline void
transmit_enquiry(struct PStack *st)
{
    if (test_bit(FLG_OWN_BUSY, &st->l2.flag))
        enquiry_cr(st, RNR, CMD, 1);
    else
        enquiry_cr(st, RR, CMD, 1);
    test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag);
    start_t200(st, 9);
}


static void
nrerrorrecovery(struct FsmInst *fi)
{
    struct PStack *st = fi->userdata;

    st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'J');
    establishlink(fi);
    test_and_clear_bit(FLG_L3_INIT, &st->l2.flag);
}

static void
invoke_retransmission(struct PStack *st, unsigned int nr)
{
    struct Layer2 *l2 = &st->l2;
    u_int p1;
    u_long flags;

    spin_lock_irqsave(&l2->lock, flags);
    if (l2->vs != nr) {
        while (l2->vs != nr) {
            (l2->vs)--;
            if (test_bit(FLG_MOD128, &l2->flag)) {
                l2->vs %= 128;
                p1 = (l2->vs - l2->va) % 128;
            } else {
                l2->vs %= 8;
                p1 = (l2->vs - l2->va) % 8;
            }
            p1 = (p1 + l2->sow) % l2->window;
            if (test_bit(FLG_LAPB, &l2->flag))
                st->l1.bcs->tx_cnt += l2->windowar[p1]->len + l2headersize(l2, 0);
            skb_queue_head(&l2->i_queue, l2->windowar[p1]);
            l2->windowar[p1] = NULL;
        }
        spin_unlock_irqrestore(&l2->lock, flags);
        st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
        return;
    }
    spin_unlock_irqrestore(&l2->lock, flags);
}

static void
l2_st7_got_super(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;
    int PollFlag, rsp, typ = RR;
    unsigned int nr;
    struct Layer2 *l2 = &st->l2;

    rsp = *skb->data & 0x2;
    if (test_bit(FLG_ORIG, &l2->flag))
        rsp = !rsp;

    skb_pull(skb, l2addrsize(l2));
    if (IsRNR(skb->data, st)) {
        set_peer_busy(l2);
        typ = RNR;
    } else
        clear_peer_busy(l2);
    if (IsREJ(skb->data, st))
        typ = REJ;

    if (test_bit(FLG_MOD128, &l2->flag)) {
        PollFlag = (skb->data[1] & 0x1) == 0x1;
        nr = skb->data[1] >> 1;
    } else {
        PollFlag = (skb->data[0] & 0x10);
        nr = (skb->data[0] >> 5) & 0x7;
    }
    dev_kfree_skb(skb);

    if (PollFlag) {
        if (rsp)
            st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'A');
        else
            enquiry_response(st);
    }
    if (legalnr(st, nr)) {
        if (typ == REJ) {
            setva(st, nr);
            invoke_retransmission(st, nr);
            stop_t200(st, 10);
            if (FsmAddTimer(&st->l2.t203, st->l2.T203,
                    EV_L2_T203, NULL, 6))
                l2m_debug(&st->l2.l2m, "Restart T203 ST7 REJ");
        } else if ((nr == l2->vs) && (typ == RR)) {
            setva(st, nr);
            stop_t200(st, 11);
            FsmRestartTimer(&st->l2.t203, st->l2.T203,
                    EV_L2_T203, NULL, 7);
        } else if ((l2->va != nr) || (typ == RNR)) {
            setva(st, nr);
            if (typ != RR) FsmDelTimer(&st->l2.t203, 9);
            restart_t200(st, 12);
        }
        if (!skb_queue_empty(&st->l2.i_queue) && (typ == RR))
            st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
    } else
        nrerrorrecovery(fi);
}

static void
l2_feed_i_if_reest(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    if (test_bit(FLG_LAPB, &st->l2.flag))
        st->l1.bcs->tx_cnt += skb->len + l2headersize(&st->l2, 0);
    if (!test_bit(FLG_L3_INIT, &st->l2.flag))
        skb_queue_tail(&st->l2.i_queue, skb);
    else
        dev_kfree_skb(skb);
}

static void
l2_feed_i_pull(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    if (test_bit(FLG_LAPB, &st->l2.flag))
        st->l1.bcs->tx_cnt += skb->len + l2headersize(&st->l2, 0);
    skb_queue_tail(&st->l2.i_queue, skb);
    st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
}

static void
l2_feed_iqueue(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    if (test_bit(FLG_LAPB, &st->l2.flag))
        st->l1.bcs->tx_cnt += skb->len + l2headersize(&st->l2, 0);
    skb_queue_tail(&st->l2.i_queue, skb);
}

static void
l2_got_iframe(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;
    struct Layer2 *l2 = &(st->l2);
    int PollFlag, ns, i;
    unsigned int nr;

    i = l2addrsize(l2);
    if (test_bit(FLG_MOD128, &l2->flag)) {
        PollFlag = ((skb->data[i + 1] & 0x1) == 0x1);
        ns = skb->data[i] >> 1;
        nr = (skb->data[i + 1] >> 1) & 0x7f;
    } else {
        PollFlag = (skb->data[i] & 0x10);
        ns = (skb->data[i] >> 1) & 0x7;
        nr = (skb->data[i] >> 5) & 0x7;
    }
    if (test_bit(FLG_OWN_BUSY, &l2->flag)) {
        dev_kfree_skb(skb);
        if (PollFlag) enquiry_response(st);
    } else if (l2->vr == ns) {
        (l2->vr)++;
        if (test_bit(FLG_MOD128, &l2->flag))
            l2->vr %= 128;
        else
            l2->vr %= 8;
        test_and_clear_bit(FLG_REJEXC, &l2->flag);

        if (PollFlag)
            enquiry_response(st);
        else
            test_and_set_bit(FLG_ACK_PEND, &l2->flag);
        skb_pull(skb, l2headersize(l2, 0));
        st->l2.l2l3(st, DL_DATA | INDICATION, skb);
    } else {
        /* n(s)!=v(r) */
        dev_kfree_skb(skb);
        if (test_and_set_bit(FLG_REJEXC, &l2->flag)) {
            if (PollFlag)
                enquiry_response(st);
        } else {
            enquiry_cr(st, REJ, RSP, PollFlag);
            test_and_clear_bit(FLG_ACK_PEND, &l2->flag);
        }
    }

    if (legalnr(st, nr)) {
        if (!test_bit(FLG_PEER_BUSY, &st->l2.flag) && (fi->state == ST_L2_7)) {
            if (nr == st->l2.vs) {
                stop_t200(st, 13);
                FsmRestartTimer(&st->l2.t203, st->l2.T203,
                        EV_L2_T203, NULL, 7);
            } else if (nr != st->l2.va)
                restart_t200(st, 14);
        }
        setva(st, nr);
    } else {
        nrerrorrecovery(fi);
        return;
    }

    if (!skb_queue_empty(&st->l2.i_queue) && (fi->state == ST_L2_7))
        st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
    if (test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag))
        enquiry_cr(st, RR, RSP, 0);
}

static void
l2_got_tei(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    st->l2.tei = (long) arg;

    if (fi->state == ST_L2_3) {
        establishlink(fi);
        test_and_set_bit(FLG_L3_INIT, &st->l2.flag);
    } else
        FsmChangeState(fi, ST_L2_4);
    if (!skb_queue_empty(&st->l2.ui_queue))
        tx_ui(st);
}

static void
l2_st5_tout_200(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    if (test_bit(FLG_LAPD, &st->l2.flag) &&
        test_bit(FLG_DCHAN_BUSY, &st->l2.flag)) {
        FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, 9);
    } else if (st->l2.rc == st->l2.N200) {
        FsmChangeState(fi, ST_L2_4);
        test_and_clear_bit(FLG_T200_RUN, &st->l2.flag);
        skb_queue_purge(&st->l2.i_queue);
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'G');
        if (test_bit(FLG_LAPB, &st->l2.flag))
            st->l2.l2l1(st, PH_DEACTIVATE | REQUEST, NULL);
        st5_dl_release_l2l3(st);
    } else {
        st->l2.rc++;
        FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, 9);
        send_uframe(st, (test_bit(FLG_MOD128, &st->l2.flag) ? SABME : SABM)
                | 0x10, CMD);
    }
}

static void
l2_st6_tout_200(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    if (test_bit(FLG_LAPD, &st->l2.flag) &&
        test_bit(FLG_DCHAN_BUSY, &st->l2.flag)) {
        FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, 9);
    } else if (st->l2.rc == st->l2.N200) {
        FsmChangeState(fi, ST_L2_4);
        test_and_clear_bit(FLG_T200_RUN, &st->l2.flag);
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'H');
        lapb_dl_release_l2l3(st, CONFIRM);
    } else {
        st->l2.rc++;
        FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200,
                NULL, 9);
        send_uframe(st, DISC | 0x10, CMD);
    }
}

static void
l2_st7_tout_200(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    if (test_bit(FLG_LAPD, &st->l2.flag) &&
        test_bit(FLG_DCHAN_BUSY, &st->l2.flag)) {
        FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, 9);
        return;
    }
    test_and_clear_bit(FLG_T200_RUN, &st->l2.flag);
    st->l2.rc = 0;
    FsmChangeState(fi, ST_L2_8);

    transmit_enquiry(st);
    st->l2.rc++;
}

static void
l2_st8_tout_200(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    if (test_bit(FLG_LAPD, &st->l2.flag) &&
        test_bit(FLG_DCHAN_BUSY, &st->l2.flag)) {
        FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, 9);
        return;
    }
    test_and_clear_bit(FLG_T200_RUN, &st->l2.flag);
    if (st->l2.rc == st->l2.N200) {
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'I');
        establishlink(fi);
        test_and_clear_bit(FLG_L3_INIT, &st->l2.flag);
    } else {
        transmit_enquiry(st);
        st->l2.rc++;
    }
}

static void
l2_st7_tout_203(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    if (test_bit(FLG_LAPD, &st->l2.flag) &&
        test_bit(FLG_DCHAN_BUSY, &st->l2.flag)) {
        FsmAddTimer(&st->l2.t203, st->l2.T203, EV_L2_T203, NULL, 9);
        return;
    }
    FsmChangeState(fi, ST_L2_8);
    transmit_enquiry(st);
    st->l2.rc = 0;
}

static void
l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb;
    struct Layer2 *l2 = &st->l2;
    u_char header[MAX_HEADER_LEN];
    int i, hdr_space_needed;
    int unsigned p1;
    u_long flags;

    if (!cansend(st))
        return;

    skb = skb_dequeue(&l2->i_queue);
    if (!skb)
        return;

    hdr_space_needed = l2headersize(l2, 0);
    if (hdr_space_needed > skb_headroom(skb)) {
        struct sk_buff *orig_skb = skb;

        skb = skb_realloc_headroom(skb, hdr_space_needed);
        if (!skb) {
            dev_kfree_skb(orig_skb);
            return;
        }
    }
    spin_lock_irqsave(&l2->lock, flags);
    if (test_bit(FLG_MOD128, &l2->flag))
        p1 = (l2->vs - l2->va) % 128;
    else
        p1 = (l2->vs - l2->va) % 8;
    p1 = (p1 + l2->sow) % l2->window;
    if (l2->windowar[p1]) {
        printk(KERN_WARNING "isdnl2 try overwrite ack queue entry %d\n",
               p1);
        dev_kfree_skb(l2->windowar[p1]);
    }
    l2->windowar[p1] = skb_clone(skb, GFP_ATOMIC);

    i = sethdraddr(&st->l2, header, CMD);

    if (test_bit(FLG_MOD128, &l2->flag)) {
        header[i++] = l2->vs << 1;
        header[i++] = l2->vr << 1;
        l2->vs = (l2->vs + 1) % 128;
    } else {
        header[i++] = (l2->vr << 5) | (l2->vs << 1);
        l2->vs = (l2->vs + 1) % 8;
    }
    spin_unlock_irqrestore(&l2->lock, flags);
    memcpy(skb_push(skb, i), header, i);
    st->l2.l2l1(st, PH_PULL | INDICATION, skb);
    test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag);
    if (!test_and_set_bit(FLG_T200_RUN, &st->l2.flag)) {
        FsmDelTimer(&st->l2.t203, 13);
        FsmAddTimer(&st->l2.t200, st->l2.T200, EV_L2_T200, NULL, 11);
    }
    if (!skb_queue_empty(&l2->i_queue) && cansend(st))
        st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
}

static void
l2_st8_got_super(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;
    int PollFlag, rsp, rnr = 0;
    unsigned int nr;
    struct Layer2 *l2 = &st->l2;

    rsp = *skb->data & 0x2;
    if (test_bit(FLG_ORIG, &l2->flag))
        rsp = !rsp;

    skb_pull(skb, l2addrsize(l2));

    if (IsRNR(skb->data, st)) {
        set_peer_busy(l2);
        rnr = 1;
    } else
        clear_peer_busy(l2);

    if (test_bit(FLG_MOD128, &l2->flag)) {
        PollFlag = (skb->data[1] & 0x1) == 0x1;
        nr = skb->data[1] >> 1;
    } else {
        PollFlag = (skb->data[0] & 0x10);
        nr = (skb->data[0] >> 5) & 0x7;
    }
    dev_kfree_skb(skb);

    if (rsp && PollFlag) {
        if (legalnr(st, nr)) {
            if (rnr) {
                restart_t200(st, 15);
            } else {
                stop_t200(st, 16);
                FsmAddTimer(&l2->t203, l2->T203,
                        EV_L2_T203, NULL, 5);
                setva(st, nr);
            }
            invoke_retransmission(st, nr);
            FsmChangeState(fi, ST_L2_7);
            if (!skb_queue_empty(&l2->i_queue) && cansend(st))
                st->l2.l2l1(st, PH_PULL | REQUEST, NULL);
        } else
            nrerrorrecovery(fi);
    } else {
        if (!rsp && PollFlag)
            enquiry_response(st);
        if (legalnr(st, nr)) {
            setva(st, nr);
        } else
            nrerrorrecovery(fi);
    }
}

static void
l2_got_FRMR(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;
    struct sk_buff *skb = arg;

    skb_pull(skb, l2addrsize(&st->l2) + 1);

    if (!(skb->data[0] & 1) || ((skb->data[0] & 3) == 1) ||     /* I or S */
        (IsUA(skb->data) && (fi->state == ST_L2_7))) {
        st->ma.layer(st, MDL_ERROR | INDICATION, (void *) 'K');
        establishlink(fi);
        test_and_clear_bit(FLG_L3_INIT, &st->l2.flag);
    }
    dev_kfree_skb(skb);
}

static void
l2_st24_tei_remove(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.ui_queue);
    st->l2.tei = -1;
    FsmChangeState(fi, ST_L2_1);
}

static void
l2_st3_tei_remove(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.ui_queue);
    st->l2.tei = -1;
    st->l2.l2l3(st, DL_RELEASE | INDICATION, NULL);
    FsmChangeState(fi, ST_L2_1);
}

static void
l2_st5_tei_remove(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    skb_queue_purge(&st->l2.ui_queue);
    freewin(st);
    st->l2.tei = -1;
    stop_t200(st, 17);
    st5_dl_release_l2l3(st);
    FsmChangeState(fi, ST_L2_1);
}

static void
l2_st6_tei_remove(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.ui_queue);
    st->l2.tei = -1;
    stop_t200(st, 18);
    st->l2.l2l3(st, DL_RELEASE | CONFIRM, NULL);
    FsmChangeState(fi, ST_L2_1);
}

static void
l2_tei_remove(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    skb_queue_purge(&st->l2.ui_queue);
    freewin(st);
    st->l2.tei = -1;
    stop_t200(st, 17);
    FsmDelTimer(&st->l2.t203, 19);
    st->l2.l2l3(st, DL_RELEASE | INDICATION, NULL);
    FsmChangeState(fi, ST_L2_1);
}

static void
l2_st14_persistent_da(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    skb_queue_purge(&st->l2.ui_queue);
    if (test_and_clear_bit(FLG_ESTAB_PEND, &st->l2.flag))
        st->l2.l2l3(st, DL_RELEASE | INDICATION, NULL);
}

static void
l2_st5_persistent_da(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    skb_queue_purge(&st->l2.ui_queue);
    freewin(st);
    stop_t200(st, 19);
    st5_dl_release_l2l3(st);
    FsmChangeState(fi, ST_L2_4);
}

static void
l2_st6_persistent_da(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.ui_queue);
    stop_t200(st, 20);
    st->l2.l2l3(st, DL_RELEASE | CONFIRM, NULL);
    FsmChangeState(fi, ST_L2_4);
}

static void
l2_persistent_da(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    skb_queue_purge(&st->l2.i_queue);
    skb_queue_purge(&st->l2.ui_queue);
    freewin(st);
    stop_t200(st, 19);
    FsmDelTimer(&st->l2.t203, 19);
    st->l2.l2l3(st, DL_RELEASE | INDICATION, NULL);
    FsmChangeState(fi, ST_L2_4);
}

static void
l2_set_own_busy(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    if (!test_and_set_bit(FLG_OWN_BUSY, &st->l2.flag)) {
        enquiry_cr(st, RNR, RSP, 0);
        test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag);
    }
}

static void
l2_clear_own_busy(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    if (!test_and_clear_bit(FLG_OWN_BUSY, &st->l2.flag)) {
        enquiry_cr(st, RR, RSP, 0);
        test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag);
    }
}

static void
l2_frame_error(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    st->ma.layer(st, MDL_ERROR | INDICATION, arg);
}

static void
l2_frame_error_reest(struct FsmInst *fi, int event, void *arg)
{
    struct PStack *st = fi->userdata;

    st->ma.layer(st, MDL_ERROR | INDICATION, arg);
    establishlink(fi);
    test_and_clear_bit(FLG_L3_INIT, &st->l2.flag);
}

static struct FsmNode L2FnList[] __initdata =
{
    {ST_L2_1, EV_L2_DL_ESTABLISH_REQ, l2_mdl_assign},
    {ST_L2_2, EV_L2_DL_ESTABLISH_REQ, l2_go_st3},
    {ST_L2_4, EV_L2_DL_ESTABLISH_REQ, l2_establish},
    {ST_L2_5, EV_L2_DL_ESTABLISH_REQ, l2_discard_i_setl3},
    {ST_L2_7, EV_L2_DL_ESTABLISH_REQ, l2_l3_reestablish},
    {ST_L2_8, EV_L2_DL_ESTABLISH_REQ, l2_l3_reestablish},
    {ST_L2_4, EV_L2_DL_RELEASE_REQ, l2_release},
    {ST_L2_5, EV_L2_DL_RELEASE_REQ, l2_pend_rel},
    {ST_L2_7, EV_L2_DL_RELEASE_REQ, l2_disconnect},
    {ST_L2_8, EV_L2_DL_RELEASE_REQ, l2_disconnect},
    {ST_L2_5, EV_L2_DL_DATA, l2_feed_i_if_reest},
    {ST_L2_7, EV_L2_DL_DATA, l2_feed_i_pull},
    {ST_L2_8, EV_L2_DL_DATA, l2_feed_iqueue},
    {ST_L2_1, EV_L2_DL_UNIT_DATA, l2_queue_ui_assign},
    {ST_L2_2, EV_L2_DL_UNIT_DATA, l2_queue_ui},
    {ST_L2_3, EV_L2_DL_UNIT_DATA, l2_queue_ui},
    {ST_L2_4, EV_L2_DL_UNIT_DATA, l2_send_ui},
    {ST_L2_5, EV_L2_DL_UNIT_DATA, l2_send_ui},
    {ST_L2_6, EV_L2_DL_UNIT_DATA, l2_send_ui},
    {ST_L2_7, EV_L2_DL_UNIT_DATA, l2_send_ui},
    {ST_L2_8, EV_L2_DL_UNIT_DATA, l2_send_ui},
    {ST_L2_1, EV_L2_MDL_ASSIGN, l2_got_tei},
    {ST_L2_2, EV_L2_MDL_ASSIGN, l2_got_tei},
    {ST_L2_3, EV_L2_MDL_ASSIGN, l2_got_tei},
    {ST_L2_2, EV_L2_MDL_ERROR, l2_st24_tei_remove},
    {ST_L2_3, EV_L2_MDL_ERROR, l2_st3_tei_remove},
    {ST_L2_4, EV_L2_MDL_REMOVE, l2_st24_tei_remove},
    {ST_L2_5, EV_L2_MDL_REMOVE, l2_st5_tei_remove},
    {ST_L2_6, EV_L2_MDL_REMOVE, l2_st6_tei_remove},
    {ST_L2_7, EV_L2_MDL_REMOVE, l2_tei_remove},
    {ST_L2_8, EV_L2_MDL_REMOVE, l2_tei_remove},
    {ST_L2_4, EV_L2_SABME, l2_start_multi},
    {ST_L2_5, EV_L2_SABME, l2_send_UA},
    {ST_L2_6, EV_L2_SABME, l2_send_DM},
    {ST_L2_7, EV_L2_SABME, l2_restart_multi},
    {ST_L2_8, EV_L2_SABME, l2_restart_multi},
    {ST_L2_4, EV_L2_DISC, l2_send_DM},
    {ST_L2_5, EV_L2_DISC, l2_send_DM},
    {ST_L2_6, EV_L2_DISC, l2_send_UA},
    {ST_L2_7, EV_L2_DISC, l2_stop_multi},
    {ST_L2_8, EV_L2_DISC, l2_stop_multi},
    {ST_L2_4, EV_L2_UA, l2_mdl_error_ua},
    {ST_L2_5, EV_L2_UA, l2_connected},
    {ST_L2_6, EV_L2_UA, l2_released},
    {ST_L2_7, EV_L2_UA, l2_mdl_error_ua},
    {ST_L2_8, EV_L2_UA, l2_mdl_error_ua},
    {ST_L2_4, EV_L2_DM, l2_reestablish},
    {ST_L2_5, EV_L2_DM, l2_st5_dm_release},
    {ST_L2_6, EV_L2_DM, l2_st6_dm_release},
    {ST_L2_7, EV_L2_DM, l2_mdl_error_dm},
    {ST_L2_8, EV_L2_DM, l2_st8_mdl_error_dm},
    {ST_L2_1, EV_L2_UI, l2_got_ui},
    {ST_L2_2, EV_L2_UI, l2_got_ui},
    {ST_L2_3, EV_L2_UI, l2_got_ui},
    {ST_L2_4, EV_L2_UI, l2_got_ui},
    {ST_L2_5, EV_L2_UI, l2_got_ui},
    {ST_L2_6, EV_L2_UI, l2_got_ui},
    {ST_L2_7, EV_L2_UI, l2_got_ui},
    {ST_L2_8, EV_L2_UI, l2_got_ui},
    {ST_L2_7, EV_L2_FRMR, l2_got_FRMR},
    {ST_L2_8, EV_L2_FRMR, l2_got_FRMR},
    {ST_L2_7, EV_L2_SUPER, l2_st7_got_super},
    {ST_L2_8, EV_L2_SUPER, l2_st8_got_super},
    {ST_L2_7, EV_L2_I, l2_got_iframe},
    {ST_L2_8, EV_L2_I, l2_got_iframe},
    {ST_L2_5, EV_L2_T200, l2_st5_tout_200},
    {ST_L2_6, EV_L2_T200, l2_st6_tout_200},
    {ST_L2_7, EV_L2_T200, l2_st7_tout_200},
    {ST_L2_8, EV_L2_T200, l2_st8_tout_200},
    {ST_L2_7, EV_L2_T203, l2_st7_tout_203},
    {ST_L2_7, EV_L2_ACK_PULL, l2_pull_iqueue},
    {ST_L2_7, EV_L2_SET_OWN_BUSY, l2_set_own_busy},
    {ST_L2_8, EV_L2_SET_OWN_BUSY, l2_set_own_busy},
    {ST_L2_7, EV_L2_CLEAR_OWN_BUSY, l2_clear_own_busy},
    {ST_L2_8, EV_L2_CLEAR_OWN_BUSY, l2_clear_own_busy},
    {ST_L2_4, EV_L2_FRAME_ERROR, l2_frame_error},
    {ST_L2_5, EV_L2_FRAME_ERROR, l2_frame_error},
    {ST_L2_6, EV_L2_FRAME_ERROR, l2_frame_error},
    {ST_L2_7, EV_L2_FRAME_ERROR, l2_frame_error_reest},
    {ST_L2_8, EV_L2_FRAME_ERROR, l2_frame_error_reest},
    {ST_L2_1, EV_L1_DEACTIVATE, l2_st14_persistent_da},
    {ST_L2_2, EV_L1_DEACTIVATE, l2_st24_tei_remove},
    {ST_L2_3, EV_L1_DEACTIVATE, l2_st3_tei_remove},
    {ST_L2_4, EV_L1_DEACTIVATE, l2_st14_persistent_da},
    {ST_L2_5, EV_L1_DEACTIVATE, l2_st5_persistent_da},
    {ST_L2_6, EV_L1_DEACTIVATE, l2_st6_persistent_da},
    {ST_L2_7, EV_L1_DEACTIVATE, l2_persistent_da},
    {ST_L2_8, EV_L1_DEACTIVATE, l2_persistent_da},
};

static void
isdnl2_l1l2(struct PStack *st, int pr, void *arg)
{
    struct sk_buff *skb = arg;
    u_char *datap;
    int ret = 1, len;
    int c = 0;

    switch (pr) {
    case (PH_DATA | INDICATION):
        datap = skb->data;
        len = l2addrsize(&st->l2);
        if (skb->len > len)
            datap += len;
        else {
            FsmEvent(&st->l2.l2m, EV_L2_FRAME_ERROR, (void *) 'N');
            dev_kfree_skb(skb);
            return;
        }
        if (!(*datap & 1)) {    /* I-Frame */
            if (!(c = iframe_error(st, skb)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_I, skb);
        } else if (IsSFrame(datap, st)) {   /* S-Frame */
            if (!(c = super_error(st, skb)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_SUPER, skb);
        } else if (IsUI(datap)) {
            if (!(c = UI_error(st, skb)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_UI, skb);
        } else if (IsSABME(datap, st)) {
            if (!(c = unnum_error(st, skb, CMD)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_SABME, skb);
        } else if (IsUA(datap)) {
            if (!(c = unnum_error(st, skb, RSP)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_UA, skb);
        } else if (IsDISC(datap)) {
            if (!(c = unnum_error(st, skb, CMD)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_DISC, skb);
        } else if (IsDM(datap)) {
            if (!(c = unnum_error(st, skb, RSP)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_DM, skb);
        } else if (IsFRMR(datap)) {
            if (!(c = FRMR_error(st, skb)))
                ret = FsmEvent(&st->l2.l2m, EV_L2_FRMR, skb);
        } else {
            FsmEvent(&st->l2.l2m, EV_L2_FRAME_ERROR, (void *) 'L');
            dev_kfree_skb(skb);
            ret = 0;
        }
        if (c) {
            dev_kfree_skb(skb);
            FsmEvent(&st->l2.l2m, EV_L2_FRAME_ERROR, (void *)(long)c);
            ret = 0;
        }
        if (ret)
            dev_kfree_skb(skb);
        break;
    case (PH_PULL | CONFIRM):
        FsmEvent(&st->l2.l2m, EV_L2_ACK_PULL, arg);
        break;
    case (PH_PAUSE | INDICATION):
        test_and_set_bit(FLG_DCHAN_BUSY, &st->l2.flag);
        break;
    case (PH_PAUSE | CONFIRM):
        test_and_clear_bit(FLG_DCHAN_BUSY, &st->l2.flag);
        break;
    case (PH_ACTIVATE | CONFIRM):
    case (PH_ACTIVATE | INDICATION):
        test_and_set_bit(FLG_L1_ACTIV, &st->l2.flag);
        if (test_and_clear_bit(FLG_ESTAB_PEND, &st->l2.flag))
            FsmEvent(&st->l2.l2m, EV_L2_DL_ESTABLISH_REQ, arg);
        break;
    case (PH_DEACTIVATE | INDICATION):
    case (PH_DEACTIVATE | CONFIRM):
        test_and_clear_bit(FLG_L1_ACTIV, &st->l2.flag);
        FsmEvent(&st->l2.l2m, EV_L1_DEACTIVATE, arg);
        break;
    default:
        l2m_debug(&st->l2.l2m, "l2 unknown pr %04x", pr);
        break;
    }
}

static void
isdnl2_l3l2(struct PStack *st, int pr, void *arg)
{
    switch (pr) {
    case (DL_DATA | REQUEST):
        if (FsmEvent(&st->l2.l2m, EV_L2_DL_DATA, arg)) {
            dev_kfree_skb((struct sk_buff *) arg);
        }
        break;
    case (DL_UNIT_DATA | REQUEST):
        if (FsmEvent(&st->l2.l2m, EV_L2_DL_UNIT_DATA, arg)) {
            dev_kfree_skb((struct sk_buff *) arg);
        }
        break;
    case (DL_ESTABLISH | REQUEST):
        if (test_bit(FLG_L1_ACTIV, &st->l2.flag)) {
            if (test_bit(FLG_LAPD, &st->l2.flag) ||
                test_bit(FLG_ORIG, &st->l2.flag)) {
                FsmEvent(&st->l2.l2m, EV_L2_DL_ESTABLISH_REQ, arg);
            }
        } else {
            if (test_bit(FLG_LAPD, &st->l2.flag) ||
                test_bit(FLG_ORIG, &st->l2.flag)) {
                test_and_set_bit(FLG_ESTAB_PEND, &st->l2.flag);
            }
            st->l2.l2l1(st, PH_ACTIVATE, NULL);
        }
        break;
    case (DL_RELEASE | REQUEST):
        if (test_bit(FLG_LAPB, &st->l2.flag)) {
            st->l2.l2l1(st, PH_DEACTIVATE, NULL);
        }
        FsmEvent(&st->l2.l2m, EV_L2_DL_RELEASE_REQ, arg);
        break;
    case (MDL_ASSIGN | REQUEST):
        FsmEvent(&st->l2.l2m, EV_L2_MDL_ASSIGN, arg);
        break;
    case (MDL_REMOVE | REQUEST):
        FsmEvent(&st->l2.l2m, EV_L2_MDL_REMOVE, arg);
        break;
    case (MDL_ERROR | RESPONSE):
        FsmEvent(&st->l2.l2m, EV_L2_MDL_ERROR, arg);
        break;
    }
}

void
releasestack_isdnl2(struct PStack *st)
{
    FsmDelTimer(&st->l2.t200, 21);
    FsmDelTimer(&st->l2.t203, 16);
    skb_queue_purge(&st->l2.i_queue);
    skb_queue_purge(&st->l2.ui_queue);
    ReleaseWin(&st->l2);
}

static void
l2m_debug(struct FsmInst *fi, char *fmt, ...)
{
    va_list args;
    struct PStack *st = fi->userdata;

    va_start(args, fmt);
    VHiSax_putstatus(st->l1.hardware, st->l2.debug_id, fmt, args);
    va_end(args);
}

void
setstack_isdnl2(struct PStack *st, char *debug_id)
{
    spin_lock_init(&st->l2.lock);
    st->l1.l1l2 = isdnl2_l1l2;
    st->l3.l3l2 = isdnl2_l3l2;

    skb_queue_head_init(&st->l2.i_queue);
    skb_queue_head_init(&st->l2.ui_queue);
    InitWin(&st->l2);
    st->l2.debug = 0;

    st->l2.l2m.fsm = &l2fsm;
    if (test_bit(FLG_LAPB, &st->l2.flag))
        st->l2.l2m.state = ST_L2_4;
    else
        st->l2.l2m.state = ST_L2_1;
    st->l2.l2m.debug = 0;
    st->l2.l2m.userdata = st;
    st->l2.l2m.userint = 0;
    st->l2.l2m.printdebug = l2m_debug;
    strcpy(st->l2.debug_id, debug_id);

    FsmInitTimer(&st->l2.l2m, &st->l2.t200);
    FsmInitTimer(&st->l2.l2m, &st->l2.t203);
}

static void
transl2_l3l2(struct PStack *st, int pr, void *arg)
{
    switch (pr) {
    case (DL_DATA | REQUEST):
    case (DL_UNIT_DATA | REQUEST):
        st->l2.l2l1(st, PH_DATA | REQUEST, arg);
        break;
    case (DL_ESTABLISH | REQUEST):
        st->l2.l2l1(st, PH_ACTIVATE | REQUEST, NULL);
        break;
    case (DL_RELEASE | REQUEST):
        st->l2.l2l1(st, PH_DEACTIVATE | REQUEST, NULL);
        break;
    }
}

void
setstack_transl2(struct PStack *st)
{
    st->l3.l3l2 = transl2_l3l2;
}

void
releasestack_transl2(struct PStack *st)
{
}

int __init
Isdnl2New(void)
{
    l2fsm.state_count = L2_STATE_COUNT;
    l2fsm.event_count = L2_EVENT_COUNT;
    l2fsm.strEvent = strL2Event;
    l2fsm.strState = strL2State;
    return FsmNew(&l2fsm, L2FnList, ARRAY_SIZE(L2FnList));
}

void
Isdnl2Free(void)
{
    FsmFree(&l2fsm);
}