/* $Id: isdn_ppp.c,v 1.63 2000/03/16 15:46:37 kai Exp $
 *
 * Linux ISDN subsystem, functions for synchronous PPP (linklevel).
 *
 * Copyright 1995,96 by Michael Hipp (Michael.Hipp@student.uni-tuebingen.de)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Log: isdn_ppp.c,v $
 * Revision 1.63  2000/03/16 15:46:37  kai
 * a little bugfix and cosmetic changes
 *
 * Revision 1.62  2000/02/12 19:26:55  kai
 * adopted to latest 2.3 softnet changes.
 *
 * tested with PPP and MPPP, it works here.
 * can somebody check raw-ip?
 *
 * also changed std2kern, stddiff for bash-1 compatibility,
 * hope this doesn't break anything.
 *
 * Revision 1.61  1999/11/20 22:14:14  detabc
 * added channel dial-skip in case of external use
 * (isdn phone or another isdn device) on the same NTBA.
 * usefull with two or more card's connected the different NTBA's.
 * global switchable in kernel-config and also per netinterface.
 *
 * add auto disable of netinterface's in case of:
 * 	to many connection's in short time.
 * 	config mistakes (wrong encapsulation, B2-protokoll or so on) on local
 * 	or remote side.
 * 	wrong password's or something else to a ISP (syncppp).
 *
 * possible encapsulations for this future are:
 * ISDN_NET_ENCAP_SYNCPPP, ISDN_NET_ENCAP_UIHDLC, ISDN_NET_ENCAP_RAWIP,
 * and ISDN_NET_ENCAP_CISCOHDLCK.
 *
 * Revision 1.60  1999/11/04 20:29:55  he
 * applied Andre Beck's reset_free fix
 *
 * Revision 1.59  1999/10/31 15:59:50  he
 * more skb headroom checks
 *
 * Revision 1.58  1999/10/30 13:13:01  keil
 * Henners isdn_ppp_skb_push:under fix
 *
 * Revision 1.57  1999/10/05 22:47:17  he
 * Removed dead ISDN_SYNCPPP_READDRESS code (obsoleted by sysctl_ip_dynaddr
 * and network address translation)
 *
 * Revision 1.56  1999/09/29 16:01:06  he
 * replaced dev_alloc_skb() for downstream skbs by equivalent alloc_skb()
 *
 * Revision 1.55  1999/09/23 22:07:51  detabc
 *
 * make ipc_head common usable (for use compressor with raw-ip)
 * add function before netif_rx(). needed for ipv4-tcp-keepalive-detect.
 * ~
 *
 * Revision 1.54  1999/09/13 23:25:17  he
 * serialized xmitting frames from isdn_ppp and BSENT statcallb
 *
 * Revision 1.53  1999/08/31 11:18:14  paul
 * various spelling corrections (new checksums may be needed, Karsten!)
 *
 * Revision 1.52  1999/08/22 20:26:07  calle
 * backported changes from kernel 2.3.14:
 * - several #include "config.h" gone, others come.
 * - "struct device" changed to "struct net_device" in 2.3.14, added a
 *   define in isdn_compat.h for older kernel versions.
 *
 * Revision 1.51  1999/08/18 16:19:17  hipp
 * applied MPPP-resize-headroom patch
 *
 * Revision 1.50  1999/08/16 07:11:41  hipp
 * Additional VJ decomp-buffer-size increased from 40 to 128
 *
 * Revision 1.49  1999/07/06 07:47:11  calle
 * bugfix: dev_alloc_skb only reserve 16 bytes. We need to look at the
 *  	hdrlen the driver want. So I changed dev_alloc_skb calls
 *         to alloc_skb and skb_reserve.
 *
 * Revision 1.48  1999/07/01 08:29:56  keil
 * compatibility to 2.3 kernel
 *
 * Revision 1.47  1999/04/18 14:06:59  fritz
 * Removed TIMRU stuff.
 *
 * Revision 1.46  1999/04/12 12:33:35  fritz
 * Changes from 2.0 tree.
 *
 * Revision 1.45  1998/12/30 17:48:24  paul
 * fixed syncPPP callback out
 *
 * Revision 1.44  1998/10/30 17:55:34  he
 * dialmode for x25iface and multulink ppp
 *
 * Revision 1.43  1998/10/29 17:23:54  hipp
 * Minor MPPP fixes, verboser logging.
 *
 * Revision 1.42  1998/07/20 11:30:07  hipp
 * Readded compression check
 *
 * Revision 1.41  1998/07/08 16:50:57  hipp
 * Compression changes
 *
 * Revision 1.40  1998/04/06 19:07:27  hipp
 * added check, whether compression is enabled.
 *
 * Revision 1.39  1998/03/25 22:46:53  hipp
 * Some additional CCP changes.
 *
 * Revision 1.38  1998/03/24 16:33:06  hipp
 * More CCP changes. BSD compression now "works" on a local loopback link.
 * Moved some isdn_ppp stuff from isdn.h to isdn_ppp.h
 *
 * Revision 1.37  1998/03/22 18:50:49  hipp
 * Added BSD Compression for syncPPP .. UNTESTED at the moment
 *
 * Revision 1.36  1998/03/09 17:46:30  he
 * merged in 2.1.89 changes
 *
 * Revision 1.35  1998/03/07 18:21:11  cal
 * Dynamic Timeout-Rule-Handling vs. 971110 included
 *
 * Revision 1.34  1998/02/25 17:49:48  he
 * Changed return codes caused be failing copy_{to,from}_user to -EFAULT
 *
 * Revision 1.33  1998/02/20 17:11:54  fritz
 * Changes for recent kernels.
 *
 * Revision 1.32  1998/01/31 19:29:55  calle
 * Merged changes from and for 2.1.82, not tested only compiled ...
 *
 * Revision 1.31  1997/10/09 21:29:01  fritz
 * New HL<->LL interface:
 *   New BSENT callback with nr. of bytes included.
 *   Sending without ACK.
 *   New L1 error status (not yet in use).
 *   Cleaned up obsolete structures.
 * Implemented Cisco-SLARP.
 * Changed local net-interface data to be dynamically allocated.
 * Removed old 2.0 compatibility stuff.
 *
 * Revision 1.30  1997/10/01 09:20:38  fritz
 * Removed old compatibility stuff for 2.0.X kernels.
 * From now on, this code is for 2.1.X ONLY!
 * Old stuff is still in the separate branch.
 *
 * Revision 1.29  1997/08/21 23:11:44  fritz
 * Added changes for kernels >= 2.1.45
 *
 * Revision 1.28  1997/06/17 13:05:57  hipp
 * Applied Eric's underflow-patches (slightly modified)
 * more compression changes (but disabled at the moment)
 * changed one copy_to_user() to run with enabled IRQs
 * a few MP changes
 * changed 'proto' handling in the isdn_ppp receive code
 *
 * Revision 1.27  1997/03/30 16:51:17  calle
 * changed calls to copy_from_user/copy_to_user and removed verify_area
 * were possible.
 *
 * Revision 1.26  1997/02/23 16:53:44  hipp
 * minor cleanup
 * some initial changes for future PPP compresion
 * added AC,PC compression for outgoing frames
 *
 * Revision 1.25  1997/02/12 20:37:35  hipp
 * New ioctl() PPPIOCGCALLINFO, minor cleanup
 *
 * Revision 1.24  1997/02/11 18:32:56  fritz
 * Bugfix in isdn_ppp_free_mpqueue().
 *
 * Revision 1.23  1997/02/10 11:12:19  fritz
 * More changes for Kernel 2.1.X compatibility.
 *
 * Revision 1.22  1997/02/06 15:03:51  hipp
 * changed GFP_KERNEL kmalloc to GFP_ATOMIC in isdn_ppp_fill_mpqueue()
 *
 * Revision 1.21  1997/02/03 23:29:38  fritz
 * Reformatted according CodingStyle
 * Bugfix: removed isdn_ppp_skb_destructor, used by upper layers.
 * Misc changes for Kernel 2.1.X compatibility.
 *
 * Revision 1.20  1996/10/30 12:21:58  fritz
 * Cosmetic fix: Compiler warning when compiling without MPP.
 *
 * Revision 1.19  1996/10/25 19:03:21  hipp
 * changed/added some defines to (re)allow compilation without MP/VJ
 *
 * Revision 1.18  1996/10/22 23:14:00  fritz
 * Changes for compatibility to 2.0.X and 2.1.X kernels.
 *
 * Revision 1.17  1996/10/22 09:39:49  hipp
 * a few MP changes and bugfixes
 *
 * Revision 1.16  1996/09/23 01:58:10  fritz
 * Fix: With syncPPP encapsulation, discard LCP packets
 *      when calculating hangup timeout.
 *
 * Revision 1.15  1996/09/07 12:50:12  hipp
 * bugfixes (unknown device after failed dial attempt, minor bugs)
 *
 * Revision 1.14  1996/08/12 16:26:47  hipp
 * code cleanup
 * changed connection management from minors to slots
 *
 * Revision 1.13  1996/07/01 19:47:24  hipp
 * Fixed memory leak in VJ handling and more VJ changes
 *
 * Revision 1.12  1996/06/24 17:42:03  fritz
 * Minor bugfixes.
 *
 * Revision 1.11  1996/06/16 17:46:05  tsbogend
 * changed unsigned long to u32 to make Alpha people happy
 *
 * Revision 1.10  1996/06/11 14:50:29  hipp
 * Lot of changes and bugfixes.
 * New scheme to resend packets to busy LL devices.
 *
 * Revision 1.9  1996/05/18 01:37:01  fritz
 * Added spelling corrections and some minor changes
 * to stay in sync with kernel.
 *
 * Revision 1.8  1996/05/06 11:34:55  hipp
 * fixed a few bugs
 *
 * Revision 1.7  1996/04/30 11:07:42  fritz
 * Added Michael's ippp-bind patch.
 *
 * Revision 1.6  1996/04/30 09:33:09  fritz
 * Removed compatibility-macros.
 *
 * Revision 1.5  1996/04/20 16:32:32  fritz
 * Changed ippp_table to an array of pointers, allocating each part
 * separately.
 *
 * Revision 1.4  1996/02/19 15:25:50  fritz
 * Bugfix: Sync-PPP packets got compressed twice, when resent due to
 * send-queue-full reject.
 *
 * Revision 1.3  1996/02/11 02:27:12  fritz
 * Lot of Bugfixes my Michael.
 * Moved calls to skb_push() into isdn_net_header()
 * Fixed a possible race-condition in isdn_ppp_timer_timeout().
 *
 * Revision 1.2  1996/01/22 05:08:06  fritz
 * Merged in Michael's patches for MP.
 * Minor changes in isdn_ppp_xmit.
 *
 * Revision 1.1  1996/01/09 04:11:29  fritz
 * Initial revision
 *
 */

/* TODO: right tbusy handling when using MP */

#define CONFIG_ISDN_CCP 1

#include <linux/config.h>
#define __NO_VERSION__
#include <linux/module.h>
#include <linux/version.h>
#include <linux/poll.h>
#include <linux/isdn.h>
#include <linux/ppp-comp.h>

#include "isdn_common.h"
#include "isdn_ppp.h"
#include "isdn_net.h"

#ifndef PPP_IPX
#define PPP_IPX 0x002b
#endif

/* set this if you use dynamic addressing */

/* Prototypes */
static int isdn_ppp_fill_rq(unsigned char *buf, int len, int proto, int slot);
static int isdn_ppp_closewait(int slot);
static void isdn_ppp_push_higher(isdn_net_dev * net_dev, isdn_net_local * lp,
				 struct sk_buff *skb, int proto);
static int isdn_ppp_if_get_unit(char *namebuf);
static int isdn_ppp_set_compressor(struct ippp_struct *is,struct isdn_ppp_comp_data *);
static struct sk_buff *isdn_ppp_decompress(struct sk_buff *,
				struct ippp_struct *,struct ippp_struct *,int proto);
static void isdn_ppp_receive_ccp(isdn_net_dev * net_dev, isdn_net_local * lp,
				struct sk_buff *skb,int proto);
static struct sk_buff *isdn_ppp_compress(struct sk_buff *skb_in,int *proto,
	struct ippp_struct *is,struct ippp_struct *master,int type);
static void isdn_ppp_send_ccp(isdn_net_dev *net_dev, isdn_net_local *lp,
	 struct sk_buff *skb);

/* New CCP stuff */
static void isdn_ppp_ccp_kickup(struct ippp_struct *is);
static void isdn_ppp_ccp_xmit_reset(struct ippp_struct *is, int proto,
				    unsigned char code, unsigned char id,
				    unsigned char *data, int len);
static struct ippp_ccp_reset *isdn_ppp_ccp_reset_alloc(struct ippp_struct *is);
static void isdn_ppp_ccp_reset_free(struct ippp_struct *is);
static void isdn_ppp_ccp_reset_free_state(struct ippp_struct *is,
					  unsigned char id);
static void isdn_ppp_ccp_timer_callback(unsigned long closure);
static struct ippp_ccp_reset_state *isdn_ppp_ccp_reset_alloc_state(struct ippp_struct *is,
						      unsigned char id);
static void isdn_ppp_ccp_reset_trans(struct ippp_struct *is,
				     struct isdn_ppp_resetparams *rp);
static void isdn_ppp_ccp_reset_ack_rcvd(struct ippp_struct *is,
					unsigned char id);



#ifdef CONFIG_ISDN_MPP
static ippp_bundle * isdn_ppp_bundle_arr = NULL;
 
static int isdn_ppp_mp_bundle_array_init(void);
static int isdn_ppp_mp_init( isdn_net_local * lp, ippp_bundle * add_to );
static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, 
							struct sk_buff *skb);
static void isdn_ppp_mp_cleanup( isdn_net_local * lp );

static int isdn_ppp_bundle(struct ippp_struct *, int unit);
  
#define MP_UNLOCK(b)	up(&(b)->lock)
#endif	/* CONFIG_ISDN_MPP */
  
char *isdn_ppp_revision = "$Revision: 1.63 $";

static struct ippp_struct *ippp_table[ISDN_MAX_CHANNELS];

static struct isdn_ppp_compressor *ipc_head = NULL;

/*
 * frame log (debug)
 */
static void
isdn_ppp_frame_log(char *info, char *data, int len, int maxlen,int unit,int slot)
{
	int cnt,
	 j,
	 i;
	char buf[80];

	if (len < maxlen)
		maxlen = len;

	for (i = 0, cnt = 0; cnt < maxlen; i++) {
		for (j = 0; j < 16 && cnt < maxlen; j++, cnt++)
			sprintf(buf + j * 3, "%02x ", (unsigned char) data[cnt]);
		printk(KERN_DEBUG "[%d/%d].%s[%d]: %s\n",unit,slot, info, i, buf);
	}
}

/*
 * unbind isdn_net_local <=> ippp-device
 * note: it can happen, that we hangup/free the master before the slaves
 *       in this case we bind another lp to the master device
 */
int
isdn_ppp_free(isdn_net_local * lp)
{
#ifdef CONFIG_ISDN_MPP
	isdn_net_local *master_lp = NULL;
#endif
	unsigned long flags;
	struct ippp_struct *is;
	isdn_net_local * nlp;

	if (lp->ppp_slot < 0 || lp->ppp_slot > ISDN_MAX_CHANNELS)
		return 0;

	is = ippp_table[lp->ppp_slot];

	save_flags(flags);
	cli();
#ifdef CONFIG_ISDN_MPP
    	spin_lock(&lp->netdev->pb->lock); // irq_save not necessary

	if (lp->master)
		master_lp = (isdn_net_local *) lp->master->priv;


	/* make sure none of the queue pointers will point to the 
	 * interface being removed */
	for (nlp=lp->next; nlp != lp; nlp=nlp->next)
		if (nlp->netdev->queue == lp )
			nlp->netdev->queue = lp->next;

	lp->last->next = lp->next;
	lp->next->last = lp->last;
	
	if (master_lp && master_lp->netdev->queue == lp)
		master_lp->netdev->queue = lp->next;
/*	
	if (lp->next->netdev->queue == lp)
		lp->next->netdev->queue = lp->next;
	if (lp->last->netdev->queue == lp)
		lp->last->netdev->queue = lp->last;
*/
	if (lp->netdev->pb->ref_ct == 1)	/* last link in queue? */
			isdn_ppp_mp_cleanup(lp);
	
	lp->next = lp->last = lp;	/* (re)set own pointers */
	lp->netdev->queue = lp;
	
	spin_unlock(&lp->netdev->pb->lock);
	lp->netdev->pb->ref_ct--;
	
#endif /* CONFIG_ISDN_MPP */

	if ((is->state & IPPP_CONNECT))
		isdn_ppp_closewait(lp->ppp_slot);	/* force wakeup on ippp device */
	else if (is->state & IPPP_ASSIGNED)
		is->state = IPPP_OPEN;	/* fallback to 'OPEN but not ASSIGNED' state */

	if (is->debug & 0x1)
		printk(KERN_DEBUG "isdn_ppp_free %d %lx %lx\n", lp->ppp_slot, (long) lp, (long) is->lp);

	is->lp = NULL;          /* link is down .. set lp to NULL */
	lp->ppp_slot = -1;      /* is this OK ?? */
	restore_flags(flags);

	return 0;
}

/*
 * bind isdn_net_local <=> ippp-device
 */
int
isdn_ppp_bind(isdn_net_local * lp)
{
	int i;
	int unit = 0;
	long flags;
	struct ippp_struct *is;

	if (lp->p_encap != ISDN_NET_ENCAP_SYNCPPP)
		return -1;

	save_flags(flags);
	cli();

	if (lp->pppbind < 0) {  /* device bounded to ippp device ? */
		isdn_net_dev *net_dev = dev->netdev;
		char exclusive[ISDN_MAX_CHANNELS];	/* exclusive flags */
		memset(exclusive, 0, ISDN_MAX_CHANNELS);
		while (net_dev) {	/* step through net devices to find exclusive minors */
			isdn_net_local *lp = net_dev->local;
			if (lp->pppbind >= 0)
				exclusive[lp->pppbind] = 1;
			net_dev = net_dev->next;
		}
		/*
		 * search a free device / slot
		 */
		for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
			if (ippp_table[i]->state == IPPP_OPEN && !exclusive[ippp_table[i]->minor]) {	/* OPEN, but not connected! */
				break;
			}
		}
	} else {
		for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
			if (ippp_table[i]->minor == lp->pppbind &&
			    (ippp_table[i]->state & IPPP_OPEN) == IPPP_OPEN)
				break;
		}
	}

	if (i >= ISDN_MAX_CHANNELS) {
		restore_flags(flags);
		printk(KERN_WARNING "isdn_ppp_bind: Can't find a (free) connection to the ipppd daemon.\n");
		return -1;
	}
	unit = isdn_ppp_if_get_unit(lp->name);	/* get unit number from interface name .. ugly! */
	if (unit < 0) {
		printk(KERN_ERR "isdn_ppp_bind: illegal interface name %s.\n", lp->name);
		return -1;
	}
	
	lp->ppp_slot = i;

	is = ippp_table[i];
	is->lp = lp;
	is->unit = unit;
	is->state = IPPP_OPEN | IPPP_ASSIGNED;	/* assigned to a netdevice but not connected */
#ifdef CONFIG_ISDN_MPP
	if (isdn_ppp_mp_init(lp, NULL) < 0)
		return -ENOMEM;
#endif /* CONFIG_ISDN_MPP */

	restore_flags(flags);

	return lp->ppp_slot;
}

/*
 * kick the ipppd on the device
 * (wakes up daemon after B-channel connect)
 */

void
isdn_ppp_wakeup_daemon(isdn_net_local * lp)
{
	if (lp->ppp_slot < 0 || lp->ppp_slot >= ISDN_MAX_CHANNELS)
		return;

	ippp_table[lp->ppp_slot]->state = IPPP_OPEN | IPPP_CONNECT | IPPP_NOBLOCK;
	
	if (ippp_table[lp->ppp_slot]->wq)
		wake_up_interruptible(&ippp_table[lp->ppp_slot]->wq);
}

/*
 * there was a hangup on the netdevice
 * force wakeup of the ippp device
 * go into 'device waits for release' state
 */
static int
isdn_ppp_closewait(int slot)
{
	struct ippp_struct *is;

	if (slot < 0 || slot >= ISDN_MAX_CHANNELS)
		return 0;
	is = ippp_table[slot];

	if (is->state && is->wq)
		wake_up_interruptible(&is->wq);

	is->state = IPPP_CLOSEWAIT;
	return 1;
}

/*
 * isdn_ppp_find_slot / isdn_ppp_free_slot
 */

static int
isdn_ppp_get_slot(void)
{
	int i;
	for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
		if (!ippp_table[i]->state)
			return i;
	}
	return -1;
}

/*
 * isdn_ppp_open
 */

int
isdn_ppp_open(int min, struct file *file)
{
	int slot;
	struct ippp_struct *is;

	if (min < 0 || min > ISDN_MAX_CHANNELS)
		return -ENODEV;

	slot = isdn_ppp_get_slot();
	if (slot < 0) {
		return -EBUSY;
	}
	is = file->private_data = ippp_table[slot];

		printk(KERN_DEBUG "ippp, open, slot: %d, minor: %d, state: %04x\n", slot, min, is->state);

	/* compression stuff */
	is->link_compressor   = is->compressor = NULL;
	is->link_decompressor = is->decompressor = NULL;
	is->link_comp_stat    = is->comp_stat = NULL;
	is->link_decomp_stat  = is->decomp_stat = NULL;
	is->compflags = 0;

	is->reset = isdn_ppp_ccp_reset_alloc(is);

	is->lp = NULL;
	is->mp_seqno = 0;       /* MP sequence number */
	is->pppcfg = 0;         /* ppp configuration */
	is->mpppcfg = 0;        /* mppp configuration */
	is->last_link_seqno = -1;	/* MP: maybe set to Bundle-MIN, when joining a bundle ?? */
	is->unit = -1;          /* set, when we have our interface */
	is->mru = 1524;         /* MRU, default 1524 */
	is->maxcid = 16;        /* VJ: maxcid */
	is->tk = current;
	is->wq = NULL;          /* read() wait queue */
	is->first = is->rq + NUM_RCV_BUFFS - 1;	/* receive queue */
	is->last = is->rq;
	is->minor = min;
#ifdef CONFIG_ISDN_PPP_VJ
	/*
	 * VJ header compression init
	 */
	is->slcomp = slhc_init(16, 16);	/* not necessary for 2. link in bundle */
#endif

	is->state = IPPP_OPEN;

	return 0;
}

/*
 * release ippp device
 */
void
isdn_ppp_release(int min, struct file *file)
{
	int i;
	struct ippp_struct *is;

	if (min < 0 || min >= ISDN_MAX_CHANNELS)
		return;
	is = file->private_data;

	if (is->debug & 0x1)
		printk(KERN_DEBUG "ippp: release, minor: %d %lx\n", min, (long) is->lp);

	if (is->lp) {           /* a lp address says: this link is still up */
		isdn_net_dev *p = is->lp->netdev;

		is->state &= ~IPPP_CONNECT;	/* -> effect: no call of wakeup */
		/*
		 * isdn_net_hangup() calls isdn_ppp_free()
		 * isdn_ppp_free() sets is->lp to NULL and lp->ppp_slot to -1
		 * removing the IPPP_CONNECT flag omits calling of isdn_ppp_wakeup_daemon()
		 */
		isdn_net_hangup(&p->dev);
	}
	for (i = 0; i < NUM_RCV_BUFFS; i++) {
		if (is->rq[i].buf) {
			kfree(is->rq[i].buf);
			is->rq[i].buf = NULL;
		}
	}
	is->first = is->rq + NUM_RCV_BUFFS - 1;	/* receive queue */
	is->last = is->rq;

#ifdef CONFIG_ISDN_PPP_VJ
/* TODO: if this was the previous master: link the slcomp to the new master */
	slhc_free(is->slcomp);
	is->slcomp = NULL;
#endif

/* TODO: if this was the previous master: link the the stuff to the new master */
	if(is->comp_stat)
		is->compressor->free(is->comp_stat);
	if(is->link_comp_stat)
		is->link_compressor->free(is->link_comp_stat);
	if(is->link_decomp_stat)
		is->link_decompressor->free(is->link_decomp_stat);
	if(is->decomp_stat)
		is->decompressor->free(is->decomp_stat);
        is->compressor   = is->link_compressor   = NULL;
        is->decompressor = is->link_decompressor = NULL;
	is->comp_stat    = is->link_comp_stat    = NULL;
        is->decomp_stat  = is->link_decomp_stat  = NULL;

	/* Clean up if necessary */
	if(is->reset)
		isdn_ppp_ccp_reset_free(is);

	/* this slot is ready for new connections */
	is->state = 0;
}

/*
 * get_arg .. ioctl helper
 */
static int
get_arg(void *b, void *val, int len)
{
	if (len <= 0)
		len = sizeof(void *);
	if (copy_from_user((void *) val, b, len))
		return -EFAULT;
	return 0;
}

/*
 * set arg .. ioctl helper
 */
static int
set_arg(void *b, void *val,int len)
{
	if(len <= 0)
		len = sizeof(void *);
	if (copy_to_user(b, (void *) val, len))
		return -EFAULT;
	return 0;
}

/*
 * ippp device ioctl
 */
int
isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
{
	unsigned long val;
	int r,i,j;
	struct ippp_struct *is;
	isdn_net_local *lp;
	struct isdn_ppp_comp_data data;

	is = (struct ippp_struct *) file->private_data;
	lp = is->lp;

	if (is->debug & 0x1)
		printk(KERN_DEBUG "isdn_ppp_ioctl: minor: %d cmd: %x state: %x\n", min, cmd, is->state);

	if (!(is->state & IPPP_OPEN))
		return -EINVAL;

	switch (cmd) {
		case PPPIOCBUNDLE:
#ifdef CONFIG_ISDN_MPP
			if (!(is->state & IPPP_CONNECT))
				return -EINVAL;
			if ((r = get_arg((void *) arg, &val, sizeof(val) )))
				return r;
			printk(KERN_DEBUG "iPPP-bundle: minor: %d, slave unit: %d, master unit: %d\n",
			       (int) min, (int) is->unit, (int) val);
			return isdn_ppp_bundle(is, val);
#else
			return -1;
#endif
			break;
		case PPPIOCGUNIT:	/* get ppp/isdn unit number */
			if ((r = set_arg((void *) arg, &is->unit, sizeof(is->unit) )))
				return r;
			break;
		case PPPIOCGIFNAME:
			if(!lp)
				return -EINVAL;
			if ((r = set_arg((void *) arg, lp->name, strlen(lp->name))))
				return r;
			break;
		case PPPIOCGMPFLAGS:	/* get configuration flags */
			if ((r = set_arg((void *) arg, &is->mpppcfg, sizeof(is->mpppcfg) )))
				return r;
			break;
		case PPPIOCSMPFLAGS:	/* set configuration flags */
			if ((r = get_arg((void *) arg, &val, sizeof(val) )))
				return r;
			is->mpppcfg = val;
			break;
		case PPPIOCGFLAGS:	/* get configuration flags */
			if ((r = set_arg((void *) arg, &is->pppcfg,sizeof(is->pppcfg) )))
				return r;
			break;
		case PPPIOCSFLAGS:	/* set configuration flags */
			if ((r = get_arg((void *) arg, &val, sizeof(val) ))) {
				return r;
			}
			if (val & SC_ENABLE_IP && !(is->pppcfg & SC_ENABLE_IP) && (is->state & IPPP_CONNECT)) {
				if (lp) {
					/* OK .. we are ready to send buffers */
					netif_wake_queue(&lp->netdev->dev);
				}
			}
			is->pppcfg = val;
			break;
		case PPPIOCGIDLE:	/* get idle time information */
			if (lp) {
				struct ppp_idle pidle;
				pidle.xmit_idle = pidle.recv_idle = lp->huptimer;
				if ((r = set_arg((void *) arg, &pidle,sizeof(struct ppp_idle))))
					 return r;
			}
			break;
		case PPPIOCSMRU:	/* set receive unit size for PPP */
			if ((r = get_arg((void *) arg, &val, sizeof(val) )))
				return r;
			is->mru = val;
			break;
		case PPPIOCSMPMRU:
			break;
		case PPPIOCSMPMTU:
			break;
		case PPPIOCSMAXCID:	/* set the maximum compression slot id */
			if ((r = get_arg((void *) arg, &val, sizeof(val) )))
				return r;
			val++;
			if (is->maxcid != val) {
#ifdef CONFIG_ISDN_PPP_VJ
				struct slcompress *sltmp;
#endif
				if (is->debug & 0x1)
					printk(KERN_DEBUG "ippp, ioctl: changed MAXCID to %ld\n", val);
				is->maxcid = val;
#ifdef CONFIG_ISDN_PPP_VJ
				sltmp = slhc_init(16, val);
				if (!sltmp) {
					printk(KERN_ERR "ippp, can't realloc slhc struct\n");
					return -ENOMEM;
				}
				if (is->slcomp)
					slhc_free(is->slcomp);
				is->slcomp = sltmp;
#endif
			}
			break;
		case PPPIOCGDEBUG:
			if ((r = set_arg((void *) arg, &is->debug, sizeof(is->debug) )))
				return r;
			break;
		case PPPIOCSDEBUG:
			if ((r = get_arg((void *) arg, &val, sizeof(val) )))
				return r;
			is->debug = val;
			break;
		case PPPIOCGCOMPRESSORS:
			{
				unsigned long protos[8] = {0,};
				struct isdn_ppp_compressor *ipc = ipc_head;
				while(ipc) {
					j = ipc->num / (sizeof(long)*8);
					i = ipc->num % (sizeof(long)*8);
					if(j < 8)
						protos[j] |= (0x1<<i);
					ipc = ipc->next;
				}
				if ((r = set_arg((void *) arg,protos,8*sizeof(long) )))
					return r;
			}
			break;
		case PPPIOCSCOMPRESSOR:
			if ((r = get_arg((void *) arg, &data, sizeof(struct isdn_ppp_comp_data))))
				return r;
			return isdn_ppp_set_compressor(is, &data);
		case PPPIOCGCALLINFO:
			{
				struct pppcallinfo pci;
				memset((char *) &pci,0,sizeof(struct pppcallinfo));
				if(lp)
				{
					strncpy(pci.local_num,lp->msn,63);
					if(lp->dial) {
						strncpy(pci.remote_num,lp->dial->num,63);
					}
					pci.charge_units = lp->charge;
					if(lp->outgoing)
						pci.calltype = CALLTYPE_OUTGOING;
					else
						pci.calltype = CALLTYPE_INCOMING;
					if(lp->flags & ISDN_NET_CALLBACK)
						pci.calltype |= CALLTYPE_CALLBACK;
				}
				return set_arg((void *)arg,&pci,sizeof(struct pppcallinfo));
			}
		default:
			break;
	}
	return 0;
}

unsigned int
isdn_ppp_poll(struct file *file, poll_table * wait)
{
	unsigned int mask;
	struct ippp_buf_queue *bf;
	struct ippp_buf_queue *bl;
	unsigned long flags;
	struct ippp_struct *is;

	is = file->private_data;

	if (is->debug & 0x2)
		printk(KERN_DEBUG "isdn_ppp_poll: minor: %d\n",
				MINOR(file->f_dentry->d_inode->i_rdev));

	/* just registers wait_queue hook. This doesn't really wait. */
	poll_wait(file, &is->wq, wait);

	if (!(is->state & IPPP_OPEN)) {
		if(is->state == IPPP_CLOSEWAIT)
			return POLLHUP;
		printk(KERN_DEBUG "isdn_ppp: device not open\n");
		return POLLERR;
	}
	/* we're always ready to send .. */
	mask = POLLOUT | POLLWRNORM;

	save_flags(flags);
	cli();
	bl = is->last;
	bf = is->first;
	/*
	 * if IPPP_NOBLOCK is set we return even if we have nothing to read
	 */
	if (bf->next != bl || (is->state & IPPP_NOBLOCK)) {
		is->state &= ~IPPP_NOBLOCK;
		mask |= POLLIN | POLLRDNORM;
	}
	restore_flags(flags);
	return mask;
}

/*
 *  fill up isdn_ppp_read() queue ..
 */

static int
isdn_ppp_fill_rq(unsigned char *buf, int len, int proto, int slot)
{
	struct ippp_buf_queue *bf,
	*bl;
	unsigned long flags;
	unsigned char *nbuf;
	struct ippp_struct *is;

	if (slot < 0 || slot >= ISDN_MAX_CHANNELS) {
		printk(KERN_WARNING "ippp: illegal slot.\n");
		return 0;
	}
	is = ippp_table[slot];

	if (!(is->state & IPPP_CONNECT)) {
		printk(KERN_DEBUG "ippp: device not activated.\n");
		return 0;
	}
	nbuf = (unsigned char *) kmalloc(len + 4, GFP_ATOMIC);
	if (!nbuf) {
		printk(KERN_WARNING "ippp: Can't alloc buf\n");
		return 0;
	}
	nbuf[0] = PPP_ALLSTATIONS;
	nbuf[1] = PPP_UI;
	nbuf[2] = proto >> 8;
	nbuf[3] = proto & 0xff;
	memcpy(nbuf + 4, buf, len);

	save_flags(flags);
	cli();

	bf = is->first;
	bl = is->last;

	if (bf == bl) {
		printk(KERN_WARNING "ippp: Queue is full; discarding first buffer\n");
		bf = bf->next;
		kfree(bf->buf);
		is->first = bf;
	}
	bl->buf = (char *) nbuf;
	bl->len = len + 4;

	is->last = bl->next;
	restore_flags(flags);

	if (is->wq)
		wake_up_interruptible(&is->wq);

	return len;
}

/*
 * read() .. non-blocking: ipppd calls it only after select()
 *           reports, that there is data
 */

int
isdn_ppp_read(int min, struct file *file, char *buf, int count)
{
	struct ippp_struct *is;
	struct ippp_buf_queue *b;
	int r;
	unsigned long flags;
	unsigned char *save_buf;

	is = file->private_data;

	if (!(is->state & IPPP_OPEN))
		return 0;

	if ((r = verify_area(VERIFY_WRITE, (void *) buf, count)))
		return r;

	save_flags(flags);
	cli();

	b = is->first->next;
	save_buf = b->buf;
	if (!save_buf) {
		restore_flags(flags);
		return -EAGAIN;
	}
	if (b->len < count)
		count = b->len;
	b->buf = NULL;
	is->first = b;

	restore_flags(flags);

	copy_to_user(buf, save_buf, count);
	kfree(save_buf);

	return count;
}

/*
 * ipppd wanna write a packet to the card .. non-blocking
 */

int
isdn_ppp_write(int min, struct file *file, const char *buf, int count)
{
	isdn_net_local *lp;
	struct ippp_struct *is;
	int proto;
	unsigned char protobuf[4];

	is = file->private_data;

	if (!(is->state & IPPP_CONNECT))
		return 0;

	lp = is->lp;

	/* -> push it directly to the lowlevel interface */

	if (!lp)
		printk(KERN_DEBUG "isdn_ppp_write: lp == NULL\n");
	else {
		/*
		 * Don't reset huptimer for
		 * LCP packets. (Echo requests).
		 */
		if (copy_from_user(protobuf, buf, 4))
			return -EFAULT;
		proto = PPP_PROTOCOL(protobuf);
		if (proto != PPP_LCP)
			lp->huptimer = 0;

		if (lp->isdn_device < 0 || lp->isdn_channel < 0)
			return 0;

		if ((dev->drv[lp->isdn_device]->flags & DRV_FLAG_RUNNING) &&
			lp->dialstate == 0 &&
		    (lp->flags & ISDN_NET_CONNECTED)) {
			unsigned short hl;
			unsigned long flags;
			int cnt;
			struct sk_buff *skb;
			/*
			 * we need to reserve enought space in front of
			 * sk_buff. old call to dev_alloc_skb only reserved
			 * 16 bytes, now we are looking what the driver want
			 */
			hl = dev->drv[lp->isdn_device]->interface->hl_hdrlen;
			skb = alloc_skb(hl+count, GFP_ATOMIC);
			if (!skb) {
				printk(KERN_WARNING "isdn_ppp_write: out of memory!\n");
				return count;
			}
			skb_reserve(skb, hl);
			if (copy_from_user(skb_put(skb, count), buf, count))
				return -EFAULT;
			if (is->debug & 0x40) {
				printk(KERN_DEBUG "ppp xmit: len %d\n", (int) skb->len);
				isdn_ppp_frame_log("xmit", skb->data, skb->len, 32,is->unit,lp->ppp_slot);
			}

			isdn_ppp_send_ccp(lp->netdev,lp,skb); /* keeps CCP/compression states in sync */

			save_flags(flags);
			cli();
			if ((cnt = isdn_writebuf_skb_stub(lp->isdn_device, lp->isdn_channel, 1, skb)) != count) {
				if (lp->sav_skb) {
					dev_kfree_skb(lp->sav_skb);
					printk(KERN_INFO "isdn_ppp_write: freeing sav_skb (%d,%d)!\n", cnt, count);
				} else
					printk(KERN_INFO "isdn_ppp_write: Can't write PPP frame to LL (%d,%d)!\n", cnt, count);
				lp->sav_skb = skb;
			}
			restore_flags(flags);
		}
	}
	return count;
}

/*
 * init memory, structures etc.
 */

int
isdn_ppp_init(void)
{
	int i,
	 j;
	 
#ifdef CONFIG_ISDN_MPP
	if( isdn_ppp_mp_bundle_array_init() < 0 )
		return -ENOMEM;
#endif /* CONFIG_ISDN_MPP */

	for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
		if (!(ippp_table[i] = (struct ippp_struct *)
		      kmalloc(sizeof(struct ippp_struct), GFP_KERNEL))) {
			printk(KERN_WARNING "isdn_ppp_init: Could not alloc ippp_table\n");
			for (j = 0; j < i; j++)
				kfree(ippp_table[i]);
			return -1;
		}
		memset((char *) ippp_table[i], 0, sizeof(struct ippp_struct));
		ippp_table[i]->state = 0;
		ippp_table[i]->first = ippp_table[i]->rq + NUM_RCV_BUFFS - 1;
		ippp_table[i]->last = ippp_table[i]->rq;

		for (j = 0; j < NUM_RCV_BUFFS; j++) {
			ippp_table[i]->rq[j].buf = NULL;
			ippp_table[i]->rq[j].last = ippp_table[i]->rq +
			    (NUM_RCV_BUFFS + j - 1) % NUM_RCV_BUFFS;
			ippp_table[i]->rq[j].next = ippp_table[i]->rq + (j + 1) % NUM_RCV_BUFFS;
		}
	}
	return 0;
}

void
isdn_ppp_cleanup(void)
{
	int i;

	for (i = 0; i < ISDN_MAX_CHANNELS; i++)
		kfree(ippp_table[i]);

#ifdef CONFIG_ISDN_MPP
	if (isdn_ppp_bundle_arr)
		kfree(isdn_ppp_bundle_arr);
#endif /* CONFIG_ISDN_MPP */

}

/*
 * get the PPP protocol header and pull skb
 */
static int isdn_ppp_strip_proto(struct sk_buff *skb) 
{
	int proto;
	if (skb->data[0] & 0x1) {
		proto = skb->data[0];
		skb_pull(skb, 1);   /* protocol ID is only 8 bit */
	} else {
		proto = ((int) skb->data[0] << 8) + skb->data[1];
		skb_pull(skb, 2);
	}
	return proto;
}


/*
 * handler for incoming packets on a syncPPP interface
 */
void isdn_ppp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, struct sk_buff *skb)
{
	struct ippp_struct *is;
	int slot;
	int proto;

	slot = lp->ppp_slot;
	if (slot < 0 || slot > ISDN_MAX_CHANNELS) {
		printk(KERN_ERR "isdn_ppp_receive: lp->ppp_slot %d\n", lp->ppp_slot);
		kfree_skb(skb);
		return;
	}
	is = ippp_table[slot];

	if (is->debug & 0x4) {
		printk(KERN_DEBUG "ippp_receive: is:%08lx lp:%08lx slot:%d unit:%d len:%d\n",
		       (long)is,(long)lp,lp->ppp_slot,is->unit,(int) skb->len);
		isdn_ppp_frame_log("receive", skb->data, skb->len, 32,is->unit,lp->ppp_slot);
	}
	if (net_dev->local->master) {
		printk(KERN_WARNING "isdn_ppp_receive: net_dev != master\n");
		net_dev = ((isdn_net_local *) net_dev->local->master->priv)->netdev;
	}
	if (skb->data[0] == 0xff && skb->data[1] == 0x03)
		skb_pull(skb, 2);
	else if (is->pppcfg & SC_REJ_COMP_AC) {
		dev_kfree_skb(skb);
		return;         /* discard it silently */
	}

	proto = isdn_ppp_strip_proto(skb);

#ifdef CONFIG_ISDN_MPP
	if (!(is->mpppcfg & SC_REJ_MP_PROT)) {

		if(is->compflags & SC_LINK_DECOMP_ON) {	
			if(proto == PPP_LINK_COMP) {
				if(is->debug & 0x10)
					printk(KERN_DEBUG "received single link compressed frame\n");
				skb = isdn_ppp_decompress(skb,is,NULL,proto);
				if(!skb)
					return;
				proto = isdn_ppp_strip_proto(skb);
			}
			else
				isdn_ppp_decompress(skb,is,NULL,proto);
		}

		if (proto == PPP_MP) {
			isdn_ppp_mp_receive(net_dev, lp, skb);
		} 
		else
			isdn_ppp_push_higher(net_dev, lp, skb, proto);
	} else
#endif /* CONFIG_ISDN_MPP */
		isdn_ppp_push_higher(net_dev, lp, skb, proto);
}

/*
 * push frame to higher layers
 * note: net_dev has to be master net_dev
 */
static void
isdn_ppp_push_higher(isdn_net_dev * net_dev, isdn_net_local * lp, struct sk_buff *skb, int proto)
{
	struct device *dev = &net_dev->dev;
	struct ippp_struct *is;
	int slot;

	slot = lp->ppp_slot;
	if (slot < 0 || slot > ISDN_MAX_CHANNELS) {
		printk(KERN_ERR "isdn_ppp_push_higher: lp->ppp_slot %d\n", lp->ppp_slot);
		kfree_skb(skb);
		return;
	}
	is = ippp_table[slot];

	if (is->debug & 0x10) {
		printk(KERN_DEBUG "push, skb %d %04x\n", (int) skb->len, proto);
		isdn_ppp_frame_log("rpush", skb->data, skb->len, 32,is->unit,lp->ppp_slot);
	}

	if(proto == PPP_COMP) {
		if(!lp->master)
			skb = isdn_ppp_decompress(skb,is,is,proto);
		else
			skb = isdn_ppp_decompress(skb,is,ippp_table[((isdn_net_local *) (lp->master->priv))->ppp_slot],proto);

		if(!skb) {
			printk(KERN_DEBUG "ippp: compressed frame discarded!\n");
			return;
		}

		proto = isdn_ppp_strip_proto(skb);
		if (is->debug & 0x10) {
			printk(KERN_DEBUG "RPostDecomp, skb %d %04x\n", (int) skb->len, proto);
			isdn_ppp_frame_log("R-Decomp", skb->data, skb->len, 32,is->unit,lp->ppp_slot);
		}
	}
	else if(is->compflags & SC_DECOMP_ON)  { /* If decomp is ON */
		if(!lp->master)
			isdn_ppp_decompress(skb,is,is,proto);
		else
			isdn_ppp_decompress(skb,is,ippp_table[((isdn_net_local *) (lp->master->priv))->ppp_slot],proto);
	}

	switch (proto) {
		case PPP_IPX:  /* untested */
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: IPX\n");
			skb->dev = dev;
			skb->mac.raw = skb->data;
			skb->protocol = htons(ETH_P_IPX);
			break;
#ifdef CONFIG_ISDN_PPP_VJ
		case PPP_VJC_UNCOMP:
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: VJC_UNCOMP\n");
			if (slhc_remember(ippp_table[net_dev->local->ppp_slot]->slcomp, skb->data, skb->len) <= 0) {
				printk(KERN_WARNING "isdn_ppp: received illegal VJC_UNCOMP frame!\n");
				net_dev->local->stats.rx_dropped++;
				dev_kfree_skb(skb);
				return;
			}
#endif
		case PPP_IP:
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: IP\n");
			skb->dev = dev;
			skb->mac.raw = skb->data;
			skb->protocol = htons(ETH_P_IP);
			break;
		case PPP_VJC_COMP:
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: VJC_COMP\n");
#ifdef CONFIG_ISDN_PPP_VJ
			{
				struct sk_buff *skb_old = skb;
				int pkt_len;
				skb = dev_alloc_skb(skb_old->len + 128);

				if (!skb) {
					printk(KERN_WARNING "%s: Memory squeeze, dropping packet.\n", dev->name);
					net_dev->local->stats.rx_dropped++;
					dev_kfree_skb(skb_old);
					return;
				}
				skb->dev = dev;
				skb_put(skb, skb_old->len + 128);
				memcpy(skb->data, skb_old->data, skb_old->len);
				skb->mac.raw = skb->data;
				pkt_len = slhc_uncompress(ippp_table[net_dev->local->ppp_slot]->slcomp,
						skb->data, skb_old->len);
				dev_kfree_skb(skb_old);
				if (pkt_len < 0) {
					dev_kfree_skb(skb);
					lp->stats.rx_dropped++;
					return;
				}
				skb_trim(skb, pkt_len);
				skb->protocol = htons(ETH_P_IP);
			}
#else
			printk(KERN_INFO "isdn: Ooopsa .. VJ-Compression support not compiled into isdn driver.\n");
			lp->stats.rx_dropped++;
			dev_kfree_skb(skb);
			return;
#endif
			break;
		case PPP_CCP:
		case PPP_LINK_CCP:
			isdn_ppp_receive_ccp(net_dev,lp,skb,proto);
			/* Dont pop up ResetReq/Ack stuff to the daemon any
			   longer - the job is done already */
			if(skb->data[0] == CCP_RESETREQ ||
			   skb->data[0] == CCP_RESETACK)
				break;
			/* fall through */
		default:
			isdn_ppp_fill_rq(skb->data, skb->len, proto, lp->ppp_slot);	/* push data to pppd device */
			dev_kfree_skb(skb);
			return;
	}

 	/* Reset hangup-timer */
 	lp->huptimer = 0;
	netif_rx(skb);
	/* net_dev->local->stats.rx_packets++; *//* done in isdn_net.c */

	return;
}

/*
 * isdn_ppp_skb_push ..
 * checks whether we have enough space at the beginning of the SKB
 * and allocs a new SKB if necessary
 */
static unsigned char *isdn_ppp_skb_push(struct sk_buff **skb_p,int len)
{
	struct sk_buff *skb = *skb_p;

	if(skb_headroom(skb) < len) {
		struct sk_buff *nskb = skb_realloc_headroom(skb, len);

		if (!nskb) {
			printk(KERN_ERR "isdn_ppp_skb_push: can't realloc headroom!\n");
			dev_kfree_skb(skb);
			return NULL;
		}
		printk(KERN_DEBUG "isdn_ppp_skb_push:under %d %d\n",skb_headroom(skb),len);
		dev_kfree_skb(skb);
		*skb_p = nskb;
		return skb_push(nskb, len);
	}
	return skb_push(skb,len);
}


/*
 * send ppp frame .. we expect a PIDCOMPressable proto --
 *  (here: currently always PPP_IP,PPP_VJC_COMP,PPP_VJC_UNCOMP)
 *
 * VJ compression may change skb pointer!!! .. requeue with old
 * skb isn't allowed!!
 */

int
isdn_ppp_xmit(struct sk_buff *skb, struct device *netdev)
{
	struct device *mdev = ((isdn_net_local *) (netdev->priv))->master;	/* get master (for redundancy) */
	isdn_net_local *lp,*mlp;
	isdn_net_dev *nd;
	unsigned int proto = PPP_IP;     /* 0x21 */
	struct ippp_struct *ipt,*ipts;
	unsigned long flags;
	int slot;

	if (mdev)
		mlp = (isdn_net_local *) (mdev->priv);
	else {
		mdev = netdev;
		mlp = (isdn_net_local *) (netdev->priv);
	}
	nd = mlp->netdev;       /* get master lp */

	slot = mlp->ppp_slot;
	if (slot < 0 || slot > ISDN_MAX_CHANNELS) {
		printk(KERN_ERR "isdn_ppp_xmit: lp->ppp_slot %d\n", mlp->ppp_slot);
		kfree_skb(skb);
		return 0;
	}
	ipts = ippp_table[slot];

	if (!(ipts->pppcfg & SC_ENABLE_IP)) {	/* PPP connected ? */
		if (ipts->debug & 0x1)
			printk(KERN_INFO "%s: IP frame delayed.\n", netdev->name);
		return 1;
	}

	switch (ntohs(skb->protocol)) {
		case ETH_P_IP:
			proto = PPP_IP;
			break;
		case ETH_P_IPX:
			proto = PPP_IPX;	/* untested */
			break;
		default:
			dev_kfree_skb(skb);
			printk(KERN_ERR "isdn_ppp: skipped frame with unsupported protocol: %#x.\n", skb->protocol);
			return 0;
	}

	lp = nd->queue;         /* get lp on top of queue */

	if (lp->sav_skb) {      /* find a non-busy device */
		isdn_net_local *nlp = lp->next;
		while (nlp->sav_skb) {
			if (lp == nlp)
				return 1;
			nlp = nd->queue = nd->queue->next;
		}
		lp = nlp;
	}
	slot = lp->ppp_slot;
	if (slot < 0 || slot > ISDN_MAX_CHANNELS) {
		printk(KERN_ERR "isdn_ppp_xmit: lp->ppp_slot %d\n", lp->ppp_slot);
		kfree_skb(skb);
		return 0;
	}
	ipt = ippp_table[slot];
	lp->huptimer = 0;

	/*
	 * after this line .. requeueing in the device queue is no longer allowed!!!
	 */

	/* Pull off the fake header we stuck on earlier to keep
     * the fragemntation code happy.
     */
	skb_pull(skb,IPPP_MAX_HEADER);

	if (ipt->debug & 0x4)
		printk(KERN_DEBUG "xmit skb, len %d\n", (int) skb->len);
        if (ipts->debug & 0x40)
                isdn_ppp_frame_log("xmit0", skb->data, skb->len, 32,ipts->unit,lp->ppp_slot);

#ifdef CONFIG_ISDN_PPP_VJ
	if (proto == PPP_IP && ipts->pppcfg & SC_COMP_TCP) {	/* ipts here? probably yes, but check this again */
		struct sk_buff *new_skb;
	        unsigned short hl;
		/*
		 * we need to reserve enought space in front of
		 * sk_buff. old call to dev_alloc_skb only reserved
		 * 16 bytes, now we are looking what the driver want.
		 */
		hl = dev->drv[lp->isdn_device]->interface->hl_hdrlen + IPPP_MAX_HEADER;
		/* 
		 * Note: hl might still be insufficient because the method
		 * above does not account for a possibible MPPP slave channel
		 * which had larger HL header space requirements than the
		 * master.
		 */
		new_skb = alloc_skb(hl+skb->len, GFP_ATOMIC);
		if (new_skb) {
			u_char *buf;
			int pktlen;

			skb_reserve(new_skb, hl);
			new_skb->dev = skb->dev;
			skb_put(new_skb, skb->len);
			buf = skb->data;

			pktlen = slhc_compress(ipts->slcomp, skb->data, skb->len, new_skb->data,
				 &buf, !(ipts->pppcfg & SC_NO_TCP_CCID));

			if (buf != skb->data) {	
				if (new_skb->data != buf)
					printk(KERN_ERR "isdn_ppp: FATAL error after slhc_compress!!\n");
				dev_kfree_skb(skb);
				skb = new_skb;
			} else {
				dev_kfree_skb(new_skb);
			}

			skb_trim(skb, pktlen);
			if (skb->data[0] & SL_TYPE_COMPRESSED_TCP) {	/* cslip? style -> PPP */
				proto = PPP_VJC_COMP;
				skb->data[0] ^= SL_TYPE_COMPRESSED_TCP;
			} else {
				if (skb->data[0] >= SL_TYPE_UNCOMPRESSED_TCP)
					proto = PPP_VJC_UNCOMP;
				skb->data[0] = (skb->data[0] & 0x0f) | 0x40;
			}
		}
	}
#endif

	/*
	 * normal (single link) or bundle compression
	 */
	if(ipts->compflags & SC_COMP_ON)
		skb = isdn_ppp_compress(skb,&proto,ipt,ipts,0);

	if (ipt->debug & 0x24)
		printk(KERN_DEBUG "xmit2 skb, len %d, proto %04x\n", (int) skb->len, proto);

#ifdef CONFIG_ISDN_MPP
	if (ipt->mpppcfg & SC_MP_PROT) {
		/* we get mp_seqno from static isdn_net_local */
		long mp_seqno = ipts->mp_seqno;
		ipts->mp_seqno++;
		nd->queue = nd->queue->next;
		if (ipt->mpppcfg & SC_OUT_SHORT_SEQ) {
			unsigned char *data = isdn_ppp_skb_push(&skb, 3);
			if(!data)
				return 0;
			mp_seqno &= 0xfff;
			data[0] = MP_BEGIN_FRAG | MP_END_FRAG | ((mp_seqno >> 8) & 0xf);	/* (B)egin & (E)ndbit .. */
			data[1] = mp_seqno & 0xff;
			data[2] = proto;	/* PID compression */
		} else {
			unsigned char *data = isdn_ppp_skb_push(&skb, 5);
			if(!data)
				return 0;
			data[0] = MP_BEGIN_FRAG | MP_END_FRAG;	/* (B)egin & (E)ndbit .. */
			data[1] = (mp_seqno >> 16) & 0xff;	/* sequence number: 24bit */
			data[2] = (mp_seqno >> 8) & 0xff;
			data[3] = (mp_seqno >> 0) & 0xff;
			data[4] = proto;	/* PID compression */
		}
		proto = PPP_MP; /* MP Protocol, 0x003d */
	}
#endif

	/*
	 * 'link in bundle' compression  ...
	 */
	if(ipt->compflags & SC_LINK_COMP_ON)
		skb = isdn_ppp_compress(skb,&proto,ipt,ipts,1);

	if( (ipt->pppcfg & SC_COMP_PROT) && (proto <= 0xff) ) {
		unsigned char *data = isdn_ppp_skb_push(&skb,1);
		if(!data)
			return 0;
		data[0] = proto & 0xff;
	}
	else {
		unsigned char *data = isdn_ppp_skb_push(&skb,2);
		if(!data)
			return 0;
		data[0] = (proto >> 8) & 0xff;
		data[1] = proto & 0xff;
	}
	if(!(ipt->pppcfg & SC_COMP_AC)) {
		unsigned char *data = isdn_ppp_skb_push(&skb,2);
		if(!data)
			return 0;
		data[0] = 0xff;    /* All Stations */
		data[1] = 0x03;    /* Unnumbered information */
	}

	/* tx-stats are now updated via BSENT-callback */

	if (ipts->debug & 0x40) {
		printk(KERN_DEBUG "skb xmit: len: %d\n", (int) skb->len);
		isdn_ppp_frame_log("xmit", skb->data, skb->len, 32,ipt->unit,lp->ppp_slot);
	}
	save_flags(flags);
	cli();
	if (isdn_net_send_skb(netdev, lp, skb)) {
		if (lp->sav_skb) {	/* should never happen as sav_skb are sent with disabled IRQs) */
			printk(KERN_ERR "%s: whoops .. there is another stored skb!\n", netdev->name);
			dev_kfree_skb(skb);
		} else
			lp->sav_skb = skb;
	}
	restore_flags(flags);
	return 0;
}

#ifdef CONFIG_ISDN_MPP

/* this is _not_ rfc1990 header, but something we convert both short and long
 * headers to for convinience's sake:
 * 	byte 0 is flags as in rfc1990
 *	bytes 1...4 is 24-bit seqence number converted to host byte order 
 */
#define MP_HEADER_LEN	5

#define MP_LONGSEQ_MASK		0x00ffffff
#define MP_SHORTSEQ_MASK	0x00000fff
#define MP_LONGSEQ_MAX		MP_LONGSEQ_MASK
#define MP_SHORTSEQ_MAX		MP_SHORTSEQ_MASK
#define MP_LONGSEQ_MAXBIT	((MP_LONGSEQ_MASK+1)>>1)
#define MP_SHORTSEQ_MAXBIT	((MP_SHORTSEQ_MASK+1)>>1)

/* sequence-wrap safe comparisions (for long sequence)*/ 
#define MP_LT(a,b)	((a-b)&MP_LONGSEQ_MAXBIT)
#define MP_LE(a,b) 	!((b-a)&MP_LONGSEQ_MAXBIT)
#define MP_GT(a,b) 	((b-a)&MP_LONGSEQ_MAXBIT)
#define MP_GE(a,b)	!((a-b)&MP_LONGSEQ_MAXBIT)

#define MP_SEQ(f)	((*(u32*)(f->data+1)))
#define MP_FLAGS(f)	(f->data[0])

static int isdn_ppp_mp_bundle_array_init(void)
{
   int i;
   int sz = ISDN_MAX_CHANNELS*sizeof(ippp_bundle);
	if( (isdn_ppp_bundle_arr = (ippp_bundle*)kmalloc(sz, 
							GFP_KERNEL)) == NULL )
		return -ENOMEM;
	memset(isdn_ppp_bundle_arr, 0, sz);
	for( i = 0; i < ISDN_MAX_CHANNELS; i++ )
		spin_lock_init(&isdn_ppp_bundle_arr[i].lock);
	return 0;
}

static ippp_bundle * isdn_ppp_mp_bundle_alloc(void)
{
    int i;
	for( i = 0; i < ISDN_MAX_CHANNELS; i++ )
		if (isdn_ppp_bundle_arr[i].ref_ct <= 0)
			return (isdn_ppp_bundle_arr + i);
	return NULL;
}

static int isdn_ppp_mp_init( isdn_net_local * lp, ippp_bundle * add_to )
{
   struct ippp_struct * is = ippp_table[lp->ppp_slot];
   
	if (add_to) {
		if( lp->netdev->pb )
			lp->netdev->pb->ref_ct--;
		lp->netdev->pb = add_to;
	} else {		/* first link in a bundle */
		is->mp_seqno = 0;
		if ((lp->netdev->pb = isdn_ppp_mp_bundle_alloc()) == NULL)
			return -ENOMEM;
		lp->next = lp->last = lp;	/* nobody else in a queue */
		lp->netdev->pb->frags = NULL;
		lp->netdev->pb->frames = 0;
		lp->netdev->pb->seq = LONG_MAX;
	}
	lp->netdev->pb->ref_ct++;
	
	is->last_link_seqno = 0;
	return 0;
}

static u32 isdn_ppp_mp_get_seq( int short_seq, 
					struct sk_buff * skb, u32 last_seq );
struct sk_buff * isdn_ppp_mp_discard( ippp_bundle * mp,
			struct sk_buff * from, struct sk_buff * to );
void isdn_ppp_mp_reassembly( isdn_net_dev * net_dev, isdn_net_local * lp,
				struct sk_buff * from, struct sk_buff * to );
static void isdn_ppp_mp_free_skb( ippp_bundle * mp, struct sk_buff * skb );
static void isdn_ppp_mp_print_recv_pkt( int slot, struct sk_buff * skb );

static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, 
							struct sk_buff *skb)
{
	struct ippp_struct *is = ippp_table[lp->ppp_slot];
	isdn_net_local * lpq;
	ippp_bundle * mp;
	isdn_mppp_stats * stats;
	struct sk_buff * newfrag, * frag, * start, *nextf;
	u32 newseq, minseq, thisseq;
	unsigned long flags;
    
    	spin_lock_irqsave(&net_dev->pb->lock, flags);
    	mp = net_dev->pb;
        stats = &mp->stats;
	
    	if( ++mp->frames > stats->max_queue_len )
		stats->max_queue_len = mp->frames;
	
	if (is->debug & 0x8)
		isdn_ppp_mp_print_recv_pkt(lp->ppp_slot, skb);

	newseq = isdn_ppp_mp_get_seq(is->mpppcfg & SC_IN_SHORT_SEQ, 
						skb, is->last_link_seqno);


	/* if this packet seq # is less than last already processed one,
	 * toss it right away, but check for sequence start case first 
	 */
	if( mp->seq > MP_LONGSEQ_MAX && (newseq & MP_LONGSEQ_MAXBIT) ) {
		mp->seq = newseq;	/* the first packet: required for
					 * rfc1990 non-compliant clients --
					 * prevents constant packet toss */
	} else if( MP_LT(newseq, mp->seq) ) {
		stats->frame_drops++;
		isdn_ppp_mp_free_skb(mp, skb);
		spin_unlock_irqrestore(&mp->lock, flags);
		return;
	}
	
	/* find the minimum received sequence number over all links */
	is->last_link_seqno = minseq = newseq;
	for (lpq = net_dev->queue;;) {
	   u32 lls = ippp_table[lpq->ppp_slot]->last_link_seqno;
		if (MP_LT(lls, minseq))
			minseq = lls;
		if ((lpq = lpq->next) == net_dev->queue)
			break;
	}
	if (MP_LT(minseq, mp->seq))
		minseq = mp->seq;	/* can't go beyond already processed
					 * packets */
	newfrag = skb;

  	/* if this new fragment is before the first one, then enqueue it now. */
  	if ((frag = mp->frags) == NULL || MP_LT(newseq, MP_SEQ(frag))) {
		newfrag->next = frag;
    		mp->frags = frag = newfrag;
    		newfrag = NULL;
  	}

  	start = MP_FLAGS(frag) & MP_BEGIN_FRAG &&
				MP_SEQ(frag) == mp->seq ? frag : NULL;

	/* 
	 * main fragment traversing loop
	 *
	 * try to accomplish several tasks:
	 * - insert new fragment into the proper sequence slot (once that's done
	 *   newfrag will be set to NULL)
	 * - reassemble any complete fragment sequence (non-null 'start'
	 *   indicates there is a continguous sequence present)
	 * - discard any incomplete sequences that are below minseq -- due
	 *   to the fact that sender always increment sequence number, if there
	 *   is an incomplete sequence below minseq, no new fragments would
	 *   come to complete such sequence and it should be discarded
	 *
	 * loop completes when we accomplished the following tasks:
	 * - new fragment is inserted in the proper sequence ('newfrag' is 
	 *   set to NULL)
	 * - we hit a gap in the sequence, so no reassembly/processing is 
	 *   possible ('start' would be set to NULL)
	 *
	 * algorightm for this code is derived from code in the book
	 * 'PPP Design And Debugging' by James Carlson (Addison-Wesley)
	 */
  	while (start != NULL || newfrag != NULL) {

    		thisseq = MP_SEQ(frag);
    		nextf = frag->next;

    		/* drop any duplicate fragments */
    		if (newfrag != NULL && thisseq == newseq) {
      			isdn_ppp_mp_free_skb(mp, newfrag);
      			newfrag = NULL;
    		}

    		/* insert new fragment before next element if possible. */
    		if (newfrag != NULL && (nextf == NULL || 
						MP_LT(newseq, MP_SEQ(nextf)))) {
      			newfrag->next = nextf;
      			frag->next = nextf = newfrag;
      			newfrag = NULL;
    		}

    		if (start != NULL) {
	    		/* check for misplaced start */
      			if (start != frag && (MP_FLAGS(frag) & MP_BEGIN_FRAG)) {
				printk(KERN_WARNING"isdn_mppp(seq %d): new "
				      "BEGIN flag with no prior END", thisseq);
				stats->seqerrs++;
				stats->frame_drops++;
				start = isdn_ppp_mp_discard(mp, start,frag);
				nextf = frag->next;
      			}
    		} else if (MP_LE(thisseq, minseq)) {		
      			if (MP_FLAGS(frag) & MP_BEGIN_FRAG)
				start = frag;
      			else {
				if (MP_FLAGS(frag) & MP_END_FRAG)
	  				stats->frame_drops++;
				if( mp->frags == frag )
					mp->frags = nextf;	
				isdn_ppp_mp_free_skb(mp, frag);
				frag = nextf;
				continue;
      			}
		}
		
		/* if start is non-null and we have end fragment, then
		 * we have full reassembly sequence -- reassemble 
		 * and process packet now
		 */
    		if (start != NULL && (MP_FLAGS(frag) & MP_END_FRAG)) {
      			minseq = mp->seq = (thisseq+1) & MP_LONGSEQ_MASK;
      			/* Reassemble the packet then dispatch it */
			isdn_ppp_mp_reassembly(net_dev, lp, start, nextf);
      
      			start = NULL;
      			frag = NULL;

      			mp->frags = nextf;
    		}

		/* check if need to update start pointer: if we just
		 * reassembled the packet and sequence is contiguous
		 * then next fragment should be the start of new reassembly
		 * if sequence is contiguous, but we haven't reassembled yet,
		 * keep going.
		 * if sequence is not contiguous, either clear everyting
		 * below low watermark and set start to the next frag or
		 * clear start ptr.
		 */ 
    		if (nextf != NULL && 
		    ((thisseq+1) & MP_LONGSEQ_MASK) == MP_SEQ(nextf)) {
      			/* if we just reassembled and the next one is here, 
			 * then start another reassembly. */

      			if (frag == NULL) {
				if (MP_FLAGS(nextf) & MP_BEGIN_FRAG)
	  				start = nextf;
				else
				{
	  				printk(KERN_WARNING"isdn_mppp(seq %d):"
						" END flag with no following "
						"BEGIN", thisseq);
					stats->seqerrs++;
				}
			}

    		} else {
			if ( nextf != NULL && frag != NULL &&
						MP_LT(thisseq, minseq)) {
				/* we've got a break in the sequence
				 * and we not at the end yet
				 * and we did not just reassembled
				 *(if we did, there wouldn't be anything before)
				 * and we below the low watermark 
			 	 * discard all the frames below low watermark 
				 * and start over */
				stats->frame_drops++;
				mp->frags = isdn_ppp_mp_discard(mp,start,nextf);
			}
			/* break in the sequence, no reassembly */
      			start = NULL;
    		}
	  			
    		frag = nextf;
  	}	/* while -- main loop */
	
  	if (mp->frags == NULL)
    		mp->frags = frag;
		
	/* rather straighforward way to deal with (not very) possible 
	 * queue overflow */
	if (mp->frames > MP_MAX_QUEUE_LEN) {
		stats->overflows++;
		while (mp->frames < MP_MAX_QUEUE_LEN) {
			frag = mp->frags->next;
			isdn_ppp_mp_free_skb(mp, mp->frags);
			mp->frags = frag;
		}
	}
	
	spin_unlock_irqrestore(&mp->lock, flags);
}

static void isdn_ppp_mp_cleanup( isdn_net_local * lp )
{
    struct sk_buff * frag = lp->netdev->pb->frags;
    struct sk_buff * nextfrag;
    	while( frag ) {
		nextfrag = frag->next;
		isdn_ppp_mp_free_skb(lp->netdev->pb, frag);
		frag = nextfrag;
	}
	lp->netdev->pb->frags = NULL;
}

static u32 isdn_ppp_mp_get_seq( int short_seq, 
					struct sk_buff * skb, u32 last_seq )
{
   u32 seq;
   int flags = skb->data[0] & (MP_BEGIN_FRAG | MP_END_FRAG);
   
   	if( !short_seq )
	{
		seq = ntohl(*(u32*)skb->data) & MP_LONGSEQ_MASK;
		skb_push(skb,1);
	}
	else
	{
		/* convert 12-bit short seq number to 24-bit long one 
	 	*/
		seq = ntohs(*(u16*)skb->data) & MP_SHORTSEQ_MASK;
	
		/* check for seqence wrap */
		if( !(seq &  MP_SHORTSEQ_MAXBIT) && 
		     (last_seq &  MP_SHORTSEQ_MAXBIT) && 
		     (unsigned long)last_seq <= MP_LONGSEQ_MAX )
			seq |= (last_seq + MP_SHORTSEQ_MAX+1) & 
					(~MP_SHORTSEQ_MASK & MP_LONGSEQ_MASK);
		else
			seq |= last_seq & (~MP_SHORTSEQ_MASK & MP_LONGSEQ_MASK);
		
		skb_push(skb, 3);	/* put converted seqence back in skb */
	}
	*(u32*)(skb->data+1) = seq; 	/* put seqence back in _host_ byte
					 * order */
	skb->data[0] = flags;	        /* restore flags */
	return seq;
}

struct sk_buff * isdn_ppp_mp_discard( ippp_bundle * mp,
			struct sk_buff * from, struct sk_buff * to )
{
	if( from )
		while (from != to) {
	  		struct sk_buff * next = from->next;
			isdn_ppp_mp_free_skb(mp, from);
	  		from = next;
		}
	return from;
}

void isdn_ppp_mp_reassembly( isdn_net_dev * net_dev, isdn_net_local * lp,
				struct sk_buff * from, struct sk_buff * to )
{
   ippp_bundle * mp = net_dev->pb;
   int proto;
   struct sk_buff * skb;
   unsigned int tot_len;
   
   	if( MP_FLAGS(from) == (MP_BEGIN_FRAG | MP_END_FRAG) )
	{
		if( ippp_table[lp->ppp_slot]->debug & 0x40 )
			printk(KERN_DEBUG"isdn_mppp: reassembly: frame %d, "
					"len %d\n", MP_SEQ(from), from->len );
		skb = from;
		skb_pull(skb, MP_HEADER_LEN);
		mp->frames--;	
	}
	else
	{
	    struct sk_buff * frag;
	    int n;
	    
		for( tot_len=0, frag=from, n = 0; frag != to; 
							frag=frag->next, n++ )
			tot_len += frag->len - MP_HEADER_LEN;
		
		if( ippp_table[lp->ppp_slot]->debug & 0x40 )
			printk(KERN_DEBUG"isdn_mppp: reassembling frames %d "
				"to %d, len %d\n", MP_SEQ(from), 
				(MP_SEQ(from)+n-1) & MP_LONGSEQ_MASK, tot_len );
		
		if( (skb = dev_alloc_skb(tot_len)) == NULL )
		{
			printk(KERN_ERR"isdn_mppp: cannot allocate sk buff "
					"of size %d\n", tot_len);
			isdn_ppp_mp_discard(mp, from, to);
			return;
		}
		
		while( from != to )
		{
		   unsigned int len = from->len - MP_HEADER_LEN;
		   	memcpy(skb_put(skb,len), from->data+MP_HEADER_LEN, len);
			frag = from->next;
			isdn_ppp_mp_free_skb(mp, from);
			from = frag; 
		}
	}
   	proto = isdn_ppp_strip_proto(skb);
	isdn_ppp_push_higher(net_dev, lp, skb, proto);
}

static void isdn_ppp_mp_free_skb(ippp_bundle * mp, struct sk_buff * skb)
{
	dev_kfree_skb(skb);
	mp->frames--;
}

static void isdn_ppp_mp_print_recv_pkt( int slot, struct sk_buff * skb )
{
	printk(KERN_DEBUG "mp_recv: %d/%d -> %02x %02x %02x %02x %02x %02x\n", 
		slot, (int) skb->len, 
		(int) skb->data[0], (int) skb->data[1], (int) skb->data[2],
		(int) skb->data[3], (int) skb->data[4], (int) skb->data[5]);
}

static int
isdn_ppp_bundle(struct ippp_struct *is, int unit)
{
	char ifn[IFNAMSIZ + 1];
	isdn_net_dev *p;
	isdn_net_local *lp,
	*nlp;
	int rc;
	unsigned long flags;

	sprintf(ifn, "ippp%d", unit);
	p = isdn_net_findif(ifn);
	if (!p)
	{
		printk(KERN_ERR "ippp_bundle: cannot find %s\n", ifn);
		return -EINVAL;
	}

    	spin_lock_irqsave(&p->pb->lock, flags);

	nlp = is->lp;

	lp = p->queue;
	
	if( nlp->ppp_slot < 0 || nlp->ppp_slot >= ISDN_MAX_CHANNELS ||
		lp->ppp_slot < 0 || lp->ppp_slot >= ISDN_MAX_CHANNELS )
	{
		spin_unlock_irqrestore(&p->pb->lock, flags);
		printk(KERN_ERR "ippp_bundle: binding to invalid slot %d\n",
		   nlp->ppp_slot < 0 || nlp->ppp_slot >= ISDN_MAX_CHANNELS ? 
		   				nlp->ppp_slot : lp->ppp_slot );
		return -EINVAL;
	}
	
	nlp->last = lp->last;
	lp->last->next = nlp;
	lp->last = nlp;
	nlp->next = lp;
	p->queue = nlp;

	ippp_table[nlp->ppp_slot]->unit = ippp_table[lp->ppp_slot]->unit;
/* maybe also SC_CCP stuff */
	ippp_table[nlp->ppp_slot]->pppcfg |= ippp_table[lp->ppp_slot]->pppcfg &
	    (SC_ENABLE_IP | SC_NO_TCP_CCID | SC_REJ_COMP_TCP);

	ippp_table[nlp->ppp_slot]->mpppcfg |= ippp_table[lp->ppp_slot]->mpppcfg &
	    (SC_MP_PROT | SC_REJ_MP_PROT | SC_OUT_SHORT_SEQ | SC_IN_SHORT_SEQ);

 	rc = isdn_ppp_mp_init(nlp, p->pb);
  
	spin_unlock_irqrestore(&p->pb->lock, flags);
  
 	return rc;
}
  
#endif /* CONFIG_ISDN_MPP */
  
/*
 * network device ioctl handlers
 */

static int
isdn_ppp_dev_ioctl_stats(int slot, struct ifreq *ifr, struct device *dev)
{
	struct ppp_stats *res,
	 t;
	isdn_net_local *lp = (isdn_net_local *) dev->priv;
	int err;

	res = (struct ppp_stats *) ifr->ifr_ifru.ifru_data;
	err = verify_area(VERIFY_WRITE, res, sizeof(struct ppp_stats));

	if (err)
		return err;

	/* build a temporary stat struct and copy it to user space */

	memset(&t, 0, sizeof(struct ppp_stats));
	if (dev->flags & IFF_UP) {
		t.p.ppp_ipackets = lp->stats.rx_packets;
		t.p.ppp_ierrors = lp->stats.rx_errors;
		t.p.ppp_opackets = lp->stats.tx_packets;
		t.p.ppp_oerrors = lp->stats.tx_errors;
#ifdef CONFIG_ISDN_PPP_VJ
		if (slot >= 0 && ippp_table[slot]->slcomp) {
			struct slcompress *slcomp = ippp_table[slot]->slcomp;
			t.vj.vjs_packets = slcomp->sls_o_compressed + slcomp->sls_o_uncompressed;
			t.vj.vjs_compressed = slcomp->sls_o_compressed;
			t.vj.vjs_searches = slcomp->sls_o_searches;
			t.vj.vjs_misses = slcomp->sls_o_misses;
			t.vj.vjs_errorin = slcomp->sls_i_error;
			t.vj.vjs_tossed = slcomp->sls_i_tossed;
			t.vj.vjs_uncompressedin = slcomp->sls_i_uncompressed;
			t.vj.vjs_compressedin = slcomp->sls_i_compressed;
		}
#endif
	}
	if( copy_to_user(res, &t, sizeof(struct ppp_stats))) return -EFAULT;
	return 0;
}

int
isdn_ppp_dev_ioctl(struct device *dev, struct ifreq *ifr, int cmd)
{
	int error=0;
	char *r;
	int len;
	isdn_net_local *lp = (isdn_net_local *) dev->priv;


	if (lp->p_encap != ISDN_NET_ENCAP_SYNCPPP)
		return -EINVAL;

	switch (cmd) {
		case SIOCGPPPVER:
			r = (char *) ifr->ifr_ifru.ifru_data;
			len = strlen(PPP_VERSION) + 1;
			if(copy_to_user(r, PPP_VERSION, len)) error = -EFAULT;
			break;
		case SIOCGPPPSTATS:
			error = isdn_ppp_dev_ioctl_stats(lp->ppp_slot, ifr, dev);
			break;
		default:
			error = -EINVAL;
			break;
	}
	return error;
}

static int
isdn_ppp_if_get_unit(char *name)
{
	int len,
	 i,
	 unit = 0,
	 deci;

	len = strlen(name);

	if (strncmp("ippp", name, 4) || len > 8)
		return -1;

	for (i = 0, deci = 1; i < len; i++, deci *= 10) {
		char a = name[len - i - 1];
		if (a >= '0' && a <= '9')
			unit += (a - '0') * deci;
		else
			break;
	}
	if (!i || len - i != 4)
		unit = -1;

	return unit;
}


int
isdn_ppp_dial_slave(char *name)
{
#ifdef CONFIG_ISDN_MPP
	isdn_net_dev *ndev;
	isdn_net_local *lp;
	struct device *sdev;

	if (!(ndev = isdn_net_findif(name)))
		return 1;
	lp = ndev->local;
	if (!(lp->flags & ISDN_NET_CONNECTED))
		return 5;

	sdev = lp->slave;
	while (sdev) {
		isdn_net_local *mlp = (isdn_net_local *) sdev->priv;
		if (!(mlp->flags & ISDN_NET_CONNECTED))
			break;
		sdev = mlp->slave;
	}
	if (!sdev)
		return 2;

	isdn_net_dial_req((isdn_net_local *) sdev->priv);
	return 0;
#else
	return -1;
#endif
}

int
isdn_ppp_hangup_slave(char *name)
{
#ifdef CONFIG_ISDN_MPP
	isdn_net_dev *ndev;
	isdn_net_local *lp;
	struct device *sdev;

	if (!(ndev = isdn_net_findif(name)))
		return 1;
	lp = ndev->local;
	if (!(lp->flags & ISDN_NET_CONNECTED))
		return 5;

	sdev = lp->slave;
	while (sdev) {
		isdn_net_local *mlp = (isdn_net_local *) sdev->priv;
		if ((mlp->flags & ISDN_NET_CONNECTED))
			break;
		sdev = mlp->slave;
	}
	if (!sdev)
		return 2;

	isdn_net_hangup(sdev);
	return 0;
#else
	return -1;
#endif
}

/*
 * PPP compression stuff
 */


/* Push an empty CCP Data Frame up to the daemon to wake it up and let it
   generate a CCP Reset-Request or tear down CCP altogether */

static void isdn_ppp_ccp_kickup(struct ippp_struct *is)
{
	isdn_ppp_fill_rq(NULL, 0, PPP_COMP, is->lp->ppp_slot);
}

/* In-kernel handling of CCP Reset-Request and Reset-Ack is necessary,
   but absolutely nontrivial. The most abstruse problem we are facing is
   that the generation, reception and all the handling of timeouts and
   resends including proper request id management should be entirely left
   to the (de)compressor, but indeed is not covered by the current API to
   the (de)compressor. The API is a prototype version from PPP where only
   some (de)compressors have yet been implemented and all of them are
   rather simple in their reset handling. Especially, their is only one
   outstanding ResetAck at a time with all of them and ResetReq/-Acks do
   not have parameters. For this very special case it was sufficient to
   just return an error code from the decompressor and have a single
   reset() entry to communicate all the necessary information between
   the framework and the (de)compressor. Bad enough, LZS is different
   (and any other compressor may be different, too). It has multiple
   histories (eventually) and needs to Reset each of them independently
   and thus uses multiple outstanding Acks and history numbers as an
   additional parameter to Reqs/Acks.
   All that makes it harder to port the reset state engine into the
   kernel because it is not just the same simple one as in (i)pppd but
   it must be able to pass additional parameters and have multiple out-
   standing Acks. We are trying to achieve the impossible by handling
   reset transactions independent by their id. The id MUST change when
   the data portion changes, thus any (de)compressor who uses more than
   one resettable state must provide and recognize individual ids for
   each individual reset transaction. The framework itself does _only_
   differentiate them by id, because it has no other semantics like the
   (de)compressor might.
   This looks like a major redesign of the interface would be nice,
   but I don't have an idea how to do it better. */

/* Send a CCP Reset-Request or Reset-Ack directly from the kernel. This is
   getting that lengthy because there is no simple "send-this-frame-out"
   function above but every wrapper does a bit different. Hope I guess
   correct in this hack... */

static void isdn_ppp_ccp_xmit_reset(struct ippp_struct *is, int proto,
				    unsigned char code, unsigned char id,
				    unsigned char *data, int len)
{
	struct sk_buff *skb;
	unsigned char *p;
	int count, hl;
	unsigned long flags;
	int cnt = 0;
	isdn_net_local *lp = is->lp;

	/* Alloc large enough skb */
	hl = dev->drv[lp->isdn_device]->interface->hl_hdrlen;
	skb = alloc_skb(len + hl + 16,GFP_ATOMIC);
	if(!skb) {
		printk(KERN_WARNING
		       "ippp: CCP cannot send reset - out of memory\n");
		return;
	}
	skb_reserve(skb, hl);

	/* We may need to stuff an address and control field first */
	if(!(is->pppcfg & SC_COMP_AC)) {
		p = skb_put(skb, 2);
		*p++ = 0xff;
		*p++ = 0x03;
	}

	/* Stuff proto, code, id and length */
	p = skb_put(skb, 6);
	*p++ = (proto >> 8);
	*p++ = (proto & 0xff);
	*p++ = code;
	*p++ = id;
	cnt = 4 + len;
	*p++ = (cnt >> 8);
	*p++ = (cnt & 0xff);

	/* Now stuff remaining bytes */
	if(len) {
		p = skb_put(skb, len);
		memcpy(p, data, len);
	}

	/* skb is now ready for xmit */
	printk(KERN_DEBUG "Sending CCP Frame:\n");
	isdn_ppp_frame_log("ccp-xmit", skb->data, skb->len, 32, is->unit,lp->ppp_slot);

	/* Just ripped from isdn_ppp_write. Dunno whether it makes sense,
	   especially dunno what the sav_skb stuff is good for. */

	count = skb->len;
	save_flags(flags);
	cli();
	if ((cnt = isdn_writebuf_skb_stub(lp->isdn_device, lp->isdn_channel,
					  1, skb)) != count) {
		if (lp->sav_skb) {
			dev_kfree_skb(lp->sav_skb);
			printk(KERN_INFO
			       "isdn_ppp_write: freeing sav_skb (%d,%d)!\n",
			       cnt, count);
		} else
			printk(KERN_INFO
			       "isdn_ppp_write: Can't write PPP frame to LL (%d,%d)!\n",
			       cnt, count);
		lp->sav_skb = skb;
	}
	restore_flags(flags);
}

/* Allocate the reset state vector */
static struct ippp_ccp_reset *isdn_ppp_ccp_reset_alloc(struct ippp_struct *is)
{
	struct ippp_ccp_reset *r;
	r = kmalloc(sizeof(struct ippp_ccp_reset), GFP_KERNEL);
	if(!r) {
		printk(KERN_ERR "ippp_ccp: failed to allocate reset data"
		       " structure - no mem\n");
		return NULL;
	}
	memset(r, 0, sizeof(struct ippp_ccp_reset));
	printk(KERN_DEBUG "ippp_ccp: allocated reset data structure %p\n", r);
	is->reset = r;
	return r;
}

/* Destroy the reset state vector. Kill all pending timers first. */
static void isdn_ppp_ccp_reset_free(struct ippp_struct *is)
{
	unsigned int id;

	printk(KERN_DEBUG "ippp_ccp: freeing reset data structure %p\n",
	       is->reset);
	for(id = 0; id < 256; id++) {
		if(is->reset->rs[id]) {
			isdn_ppp_ccp_reset_free_state(is, (unsigned char)id);
		}
	}
	kfree(is->reset);
	is->reset = NULL;
}

/* Free a given state and clear everything up for later reallocation */
static void isdn_ppp_ccp_reset_free_state(struct ippp_struct *is,
					  unsigned char id)
{
	struct ippp_ccp_reset_state *rs;

	if(is->reset->rs[id]) {
		printk(KERN_DEBUG "ippp_ccp: freeing state for id %d\n", id);
		rs = is->reset->rs[id];
		/* Make sure the kernel will not call back later */
		if(rs->ta)
			del_timer(&rs->timer);
		is->reset->rs[id] = NULL;
		kfree(rs);
	} else {
		printk(KERN_WARNING "ippp_ccp: id %d is not allocated\n", id);
	}
}

/* The timer callback function which is called when a ResetReq has timed out,
   aka has never been answered by a ResetAck */
static void isdn_ppp_ccp_timer_callback(unsigned long closure)
{
	struct ippp_ccp_reset_state *rs =
		(struct ippp_ccp_reset_state *)closure;

	if(!rs) {
		printk(KERN_ERR "ippp_ccp: timer cb with zero closure.\n");
		return;
	}
	if(rs->ta && rs->state == CCPResetSentReq) {
		/* We are correct here */
		printk(KERN_DEBUG "ippp_ccp: CCP Reset timed out for id %d\n",
		       rs->id);
		if(!rs->expra) {
			/* Hmm, there is no Ack really expected. We can clean
			   up the state now, it will be reallocated if the
			   decompressor insists on another reset */
			rs->ta = 0;
			isdn_ppp_ccp_reset_free_state(rs->is, rs->id);
			return;
		}
		/* Push it again */
		isdn_ppp_ccp_xmit_reset(rs->is, PPP_CCP, CCP_RESETREQ, rs->id,
					rs->data, rs->dlen);
		/* Restart timer */
		rs->timer.expires = jiffies + HZ*5;
		add_timer(&rs->timer);
	} else {
		printk(KERN_WARNING "ippp_ccp: timer cb in wrong state %d\n",
		       rs->state);
	}
}

/* Allocate a new reset transaction state */
static struct ippp_ccp_reset_state *isdn_ppp_ccp_reset_alloc_state(struct ippp_struct *is,
						      unsigned char id)
{
	struct ippp_ccp_reset_state *rs;
	if(is->reset->rs[id]) {
		printk(KERN_WARNING "ippp_ccp: old state exists for id %d\n",
		       id);
		return NULL;
	} else {
		rs = kmalloc(sizeof(struct ippp_ccp_reset_state), GFP_KERNEL);
		if(!rs)
			return NULL;
		memset(rs, 0, sizeof(struct ippp_ccp_reset_state));
		rs->state = CCPResetIdle;
		rs->is = is;
		rs->id = id;
		rs->timer.data = (unsigned long)rs;
		rs->timer.function = isdn_ppp_ccp_timer_callback;
		is->reset->rs[id] = rs;
	}
	return rs;
}


/* A decompressor wants a reset with a set of parameters - do what is
   necessary to fulfill it */
static void isdn_ppp_ccp_reset_trans(struct ippp_struct *is,
				     struct isdn_ppp_resetparams *rp)
{
	struct ippp_ccp_reset_state *rs;

	if(rp->valid) {
		/* The decompressor defines parameters by itself */
		if(rp->rsend) {
			/* And he wants us to send a request */
			if(!(rp->idval)) {
				printk(KERN_ERR "ippp_ccp: decompressor must"
				       " specify reset id\n");
				return;
			}
			if(is->reset->rs[rp->id]) {
				/* There is already a transaction in existence
				   for this id. May be still waiting for a
				   Ack or may be wrong. */
				rs = is->reset->rs[rp->id];
				if(rs->state == CCPResetSentReq && rs->ta) {
					printk(KERN_DEBUG "ippp_ccp: reset"
					       " trans still in progress"
					       " for id %d\n", rp->id);
				} else {
					printk(KERN_WARNING "ippp_ccp: reset"
					       " trans in wrong state %d for"
					       " id %d\n", rs->state, rp->id);
				}
			} else {
				/* Ok, this is a new transaction */
				printk(KERN_DEBUG "ippp_ccp: new trans for id"
				       " %d to be started\n", rp->id);
				rs = isdn_ppp_ccp_reset_alloc_state(is, rp->id);
				if(!rs) {
					printk(KERN_ERR "ippp_ccp: out of mem"
					       " allocing ccp trans\n");
					return;
				}
				rs->state = CCPResetSentReq;
				rs->expra = rp->expra;
				if(rp->dtval) {
					rs->dlen = rp->dlen;
					memcpy(rs->data, rp->data, rp->dlen);
				}
				/* HACK TODO - add link comp here */
				isdn_ppp_ccp_xmit_reset(is, PPP_CCP,
							CCP_RESETREQ, rs->id,
							rs->data, rs->dlen);
				/* Start the timer */
				rs->timer.expires = jiffies + 5*HZ;
				add_timer(&rs->timer);
				rs->ta = 1;
			}
		} else {
			printk(KERN_DEBUG "ippp_ccp: no reset sent\n");
		}
	} else {
		/* The reset params are invalid. The decompressor does not
		   care about them, so we just send the minimal requests
		   and increase ids only when an Ack is received for a
		   given id */
		if(is->reset->rs[is->reset->lastid]) {
			/* There is already a transaction in existence
			   for this id. May be still waiting for a
			   Ack or may be wrong. */
			rs = is->reset->rs[is->reset->lastid];
			if(rs->state == CCPResetSentReq && rs->ta) {
				printk(KERN_DEBUG "ippp_ccp: reset"
				       " trans still in progress"
				       " for id %d\n", rp->id);
			} else {
				printk(KERN_WARNING "ippp_ccp: reset"
				       " trans in wrong state %d for"
				       " id %d\n", rs->state, rp->id);
			}
		} else {
			printk(KERN_DEBUG "ippp_ccp: new trans for id"
			       " %d to be started\n", is->reset->lastid);
			rs = isdn_ppp_ccp_reset_alloc_state(is,
							    is->reset->lastid);
			if(!rs) {
				printk(KERN_ERR "ippp_ccp: out of mem"
				       " allocing ccp trans\n");
				return;
			}
			rs->state = CCPResetSentReq;
			/* We always expect an Ack if the decompressor doesnt
			   know	better */
			rs->expra = 1;
			rs->dlen = 0;
			/* HACK TODO - add link comp here */
			isdn_ppp_ccp_xmit_reset(is, PPP_CCP, CCP_RESETREQ,
						rs->id, NULL, 0);
			/* Start the timer */
			rs->timer.expires = jiffies + 5*HZ;
			add_timer(&rs->timer);
			rs->ta = 1;
		}
	}
}

/* An Ack was received for this id. This means we stop the timer and clean
   up the state prior to calling the decompressors reset routine. */
static void isdn_ppp_ccp_reset_ack_rcvd(struct ippp_struct *is,
					unsigned char id)
{
	struct ippp_ccp_reset_state *rs = is->reset->rs[id];

	if(rs) {
		if(rs->ta && rs->state == CCPResetSentReq) {
			/* Great, we are correct */
			if(!rs->expra)
				printk(KERN_DEBUG "ippp_ccp: ResetAck received"
				       " for id %d but not expected\n", id);
		} else {
			printk(KERN_INFO "ippp_ccp: ResetAck received out of"
			       "sync for id %d\n", id);
		}
		if(rs->ta) {
			rs->ta = 0;
			del_timer(&rs->timer);
		}
		isdn_ppp_ccp_reset_free_state(is, id);
	} else {
		printk(KERN_INFO "ippp_ccp: ResetAck received for unknown id"
		       " %d\n", id);
	}
	/* Make sure the simple reset stuff uses a new id next time */
	is->reset->lastid++;
}

static struct sk_buff *isdn_ppp_decompress(struct sk_buff *skb,struct ippp_struct *is,struct ippp_struct *master,
	int proto)
{
#ifndef CONFIG_ISDN_CCP
	if(proto == PPP_COMP || proto == PPP_LINK_COMP) {
		printk(KERN_ERR "isdn_ppp: Ouch! Compression not included!\n");
		dev_kfree_skb(skb);
		return NULL;
	}
	return skb;
#else
	void *stat = NULL;
	struct isdn_ppp_compressor *ipc = NULL;
	struct sk_buff *skb_out;
	int len;
	struct ippp_struct *ri;
	struct isdn_ppp_resetparams rsparm;
	unsigned char rsdata[IPPP_RESET_MAXDATABYTES];

	if(!master) {
		/* 
		 * single link decompression 
		 */
		if(!is->link_decompressor) {
			printk(KERN_ERR "ippp: no link decompressor defined!\n");
			dev_kfree_skb(skb);
			return NULL;
		}
		if(!is->link_decomp_stat) {
			printk(KERN_DEBUG "ippp: no link decompressor data allocated\n");
			dev_kfree_skb(skb);
			return NULL;
		}
		stat = is->link_decomp_stat;
		ipc = is->link_decompressor;
		ri = is;
	}
	else {
		/*
		 * 'normal' or bundle-compression 
		 */
		if(!master->decompressor) {
			printk(KERN_ERR "ippp: no decompressor defined!\n");
			dev_kfree_skb(skb);
			return NULL;
		}
		if(!master->decomp_stat) {
			printk(KERN_DEBUG "ippp: no decompressor data allocated\n");
			dev_kfree_skb(skb);
			return NULL;
		}
		stat = master->decomp_stat;
		ipc = master->decompressor;
		ri = master;
	}

	/*
	printk(KERN_DEBUG "ippp: Decompress valid!\n");
	*/

	if((master && proto == PPP_COMP) || (!master && proto == PPP_LINK_COMP) ) {
		/* Set up reset params for the decompressor */
		memset(&rsparm, 0, sizeof(rsparm));
		rsparm.data = rsdata;
		rsparm.maxdlen = IPPP_RESET_MAXDATABYTES;

/* !!!HACK,HACK,HACK!!! 2048 is only assumed */
		skb_out = dev_alloc_skb(2048);
		len = ipc->decompress(stat,skb,skb_out, &rsparm);
		dev_kfree_skb(skb);
		if(len <= 0) {
		  /* Ok, some error */
		  switch(len) {
		  case DECOMP_ERROR:
		    ri->pppcfg |= SC_DC_ERROR;
		    printk(KERN_INFO "ippp: decomp wants reset %s params\n",
			   rsparm.valid ? "with" : "without");

		    isdn_ppp_ccp_reset_trans(ri, &rsparm);

		    break;
		  case DECOMP_FATALERROR:
		    ri->pppcfg |= SC_DC_FERROR;
		    /* Kick ipppd to recognize the error */
		    isdn_ppp_ccp_kickup(ri);
		    break;
		  }
		  /* Did I see a leak here ? */
		  dev_kfree_skb(skb_out);
		  return NULL;
		}
		return skb_out;
	}
	else {
		/*
		printk(KERN_DEBUG "isdn_ppp: [%d] Calling incomp with this frame!\n",is->unit);
		*/
		ipc->incomp(stat,skb,proto);
		return skb;
	}
#endif
}

/*
 * compress a frame 
 *   type=0: normal/bundle compression
 *       =1: link compression
 * returns original skb if we haven't compressed the frame
 * and a new skb pointer if we've done it
 */
static struct sk_buff *isdn_ppp_compress(struct sk_buff *skb_in,int *proto,
	struct ippp_struct *is,struct ippp_struct *master,int type)
{
    int ret;
    int new_proto;
    struct isdn_ppp_compressor *compressor;
    void *stat;
    struct sk_buff *skb_out;

#ifdef CONFIG_ISDN_CCP
	/* we do not compress control protocols */
    if(*proto < 0 || *proto > 0x3fff) {
#else
    {
#endif
      return skb_in;
    }

	if(type) { /* type=1 => Link compression */
		return skb_in;
	}
	else {
		if(!master) {
			compressor = is->compressor;
			stat = is->comp_stat;
		}
		else {
			compressor = master->compressor;
			stat = master->comp_stat;
		}
		new_proto = PPP_COMP;
	}

	if(!compressor) {
		printk(KERN_ERR "isdn_ppp: No compressor set!\n");
		return skb_in;
	}
	if(!stat) {
		printk(KERN_ERR "isdn_ppp: Compressor not initialized?\n");
		return skb_in;
	}

	/* Allow for at least 150 % expansion (for now) */
	skb_out = alloc_skb(skb_in->len + skb_in->len/2 + 32 +
		skb_headroom(skb_in), GFP_ATOMIC);
	if(!skb_out)
		return skb_in;
	skb_reserve(skb_out, skb_headroom(skb_in));

	ret = (compressor->compress)(stat,skb_in,skb_out,*proto);
	if(!ret) {
		dev_kfree_skb(skb_out);
		return skb_in;
	}
	
	dev_kfree_skb(skb_in);
	*proto = new_proto;
	return skb_out;
}

/*
 * we received a CCP frame .. 
 * not a clean solution, but we MUST handle a few cases in the kernel
 */
static void isdn_ppp_receive_ccp(isdn_net_dev *net_dev, isdn_net_local *lp,
	 struct sk_buff *skb,int proto)
{
	struct ippp_struct *is = ippp_table[lp->ppp_slot];
	struct ippp_struct *mis;
	int len;
	struct isdn_ppp_resetparams rsparm;
	unsigned char rsdata[IPPP_RESET_MAXDATABYTES];	

	printk(KERN_DEBUG "Received CCP frame from peer\n");
	isdn_ppp_frame_log("ccp-rcv", skb->data, skb->len, 32, is->unit,lp->ppp_slot);

	if(lp->master)
		mis = ippp_table[((isdn_net_local *) (lp->master->priv))->ppp_slot];
	else
		mis = is;

	switch(skb->data[0]) {
	case CCP_CONFREQ:
	case CCP_TERMREQ:
	case CCP_TERMACK:
		if(is->debug & 0x10)
			printk(KERN_DEBUG "Disable (de)compression here!\n");
		if(proto == PPP_CCP)
			mis->compflags &= ~(SC_DECOMP_ON|SC_COMP_ON);		
		else
			is->compflags &= ~(SC_LINK_DECOMP_ON|SC_LINK_COMP_ON);		
		break;
	case CCP_CONFACK:
		/* if we RECEIVE an ackowledge we enable the decompressor */
		if(is->debug & 0x10)
			printk(KERN_DEBUG "Enable decompression here!\n");
		if(proto == PPP_CCP)
			mis->compflags |= SC_DECOMP_ON;
		else
			is->compflags |= SC_LINK_DECOMP_ON;
		break;

	case CCP_RESETACK:
		printk(KERN_DEBUG "Received ResetAck from peer\n");
		len = (skb->data[2] << 8) | skb->data[3];
		len -= 4;

		if(proto == PPP_CCP) {
			/* If a reset Ack was outstanding for this id, then
			   clean up the state engine */
			isdn_ppp_ccp_reset_ack_rcvd(mis, skb->data[1]);
			if(mis->decompressor && mis->decomp_stat)
				mis->decompressor->
					reset(mis->decomp_stat,
					      skb->data[0],
					      skb->data[1],
					      len ? &skb->data[4] : NULL,
					      len, NULL);
			/* TODO: This is not easy to decide here */
			mis->compflags &= ~SC_DECOMP_DISCARD;
			mis->pppcfg &= ~SC_DC_ERROR;
		}
		else {
			isdn_ppp_ccp_reset_ack_rcvd(is, skb->data[1]);
			if(is->link_decompressor && is->link_decomp_stat)
				is->link_decompressor->
					reset(is->link_decomp_stat,
					      skb->data[0],
					      skb->data[1],
					      len ? &skb->data[4] : NULL,
					      len, NULL);
			/* TODO: neither here */
			is->compflags &= ~SC_LINK_DECOMP_DISCARD;
			is->pppcfg &= ~SC_DC_ERROR;
		}
		break;

	case CCP_RESETREQ:
		printk(KERN_DEBUG "Received ResetReq from peer\n");
		/* Receiving a ResetReq means we must reset our compressor */
		/* Set up reset params for the reset entry */
		memset(&rsparm, 0, sizeof(rsparm));
		rsparm.data = rsdata;
		rsparm.maxdlen = IPPP_RESET_MAXDATABYTES; 
		/* Isolate data length */
		len = (skb->data[2] << 8) | skb->data[3];
		len -= 4;
		if(proto == PPP_CCP) {
			if(mis->compressor && mis->comp_stat)
				mis->compressor->
					reset(mis->comp_stat,
					      skb->data[0],
					      skb->data[1],
					      len ? &skb->data[4] : NULL,
					      len, &rsparm);
		}
		else {
			if(is->link_compressor && is->link_comp_stat)
				is->link_compressor->
					reset(is->link_comp_stat,
					      skb->data[0],
					      skb->data[1],
					      len ? &skb->data[4] : NULL,
					      len, &rsparm);
		}
		/* Ack the Req as specified by rsparm */
		if(rsparm.valid) {
			/* Compressor reset handler decided how to answer */
			if(rsparm.rsend) {
				/* We should send a Frame */
				isdn_ppp_ccp_xmit_reset(is, proto, CCP_RESETACK,
							rsparm.idval ? rsparm.id
							: skb->data[1],
							rsparm.dtval ?
							rsparm.data : NULL,
							rsparm.dtval ?
							rsparm.dlen : 0);
			} else {
				printk(KERN_DEBUG "ResetAck suppressed\n");
			}
		} else {
			/* We answer with a straight reflected Ack */
			isdn_ppp_ccp_xmit_reset(is, proto, CCP_RESETACK,
						skb->data[1],
						len ? &skb->data[4] : NULL,
						len);
		}
		break;
	}
}


/*
 * Daemon sends a CCP frame ...
 */

/* TODO: Clean this up with new Reset semantics */

static void isdn_ppp_send_ccp(isdn_net_dev *net_dev, isdn_net_local *lp, struct sk_buff *skb)
{
	struct ippp_struct *mis,*is = ippp_table[lp->ppp_slot];
	int proto;
	unsigned char *data;

	if(!skb || skb->len < 3)
		return;

	/* Daemon may send with or without address and control field comp */
	data = skb->data;
	if(!(is->pppcfg & SC_COMP_AC) && data[0] == 0xff && data[1] == 0x03) {
		data += 2;
		if(skb->len < 5)
			return;
	}

	proto = ((int)data[0]<<8)+data[1];
	if(proto != PPP_CCP && proto != PPP_LINK_CCP)
		return;

	printk(KERN_DEBUG "Received CCP frame from daemon:\n");
	isdn_ppp_frame_log("ccp-xmit", skb->data, skb->len, 32, is->unit,lp->ppp_slot);

        if(lp->master)
                mis = ippp_table[((isdn_net_local *) (lp->master->priv))->ppp_slot];
        else
                mis = is;
	
	if(mis != is)
		printk(KERN_DEBUG "isdn_ppp: Ouch! Master CCP sends on slave slot!\n");
	
        switch(data[2]) {
	case CCP_CONFREQ:
	case CCP_TERMREQ:
	case CCP_TERMACK:
		if(is->debug & 0x10)
			printk(KERN_DEBUG "Disable (de)compression here!\n");
		if(proto == PPP_CCP)
			is->compflags &= ~(SC_DECOMP_ON|SC_COMP_ON);
		else
			is->compflags &= ~(SC_LINK_DECOMP_ON|SC_LINK_COMP_ON);
		break;
	case CCP_CONFACK:
		/* if we SEND an ackowledge we can/must enable the compressor */
		if(is->debug & 0x10)
			printk(KERN_DEBUG "Enable compression here!\n");
		if(proto == PPP_CCP)
			is->compflags |= SC_COMP_ON;
		else
			is->compflags |= SC_LINK_COMP_ON;
		break;
	case CCP_RESETACK:
		/* If we send a ACK we should reset our compressor */
		if(is->debug & 0x10)
			printk(KERN_DEBUG "Reset decompression state here!\n");
		printk(KERN_DEBUG "ResetAck from daemon passed by\n");
		if(proto == PPP_CCP) {
			/* link to master? */
			if(is->compressor && is->comp_stat)
				is->compressor->reset(is->comp_stat, 0, 0,
						      NULL, 0, NULL);
			is->compflags &= ~SC_COMP_DISCARD;	
		}
		else {
			if(is->link_compressor && is->link_comp_stat)
				is->link_compressor->reset(is->link_comp_stat,
							   0, 0, NULL, 0, NULL);
			is->compflags &= ~SC_LINK_COMP_DISCARD;	
		}
		break;
	case CCP_RESETREQ:
		/* Just let it pass by */
		printk(KERN_DEBUG "ResetReq from daemon passed by\n");
		break;
	}
}

int isdn_ppp_register_compressor(struct isdn_ppp_compressor *ipc)
{
	ipc->next = ipc_head;
	ipc->prev = NULL;
	if(ipc_head) {
		ipc_head->prev = ipc;
	}
	ipc_head = ipc;
	return 0;
}

int isdn_ppp_unregister_compressor(struct isdn_ppp_compressor *ipc)
{
	if(ipc->prev)
		ipc->prev->next = ipc->next;
	else
		ipc_head = ipc->next;
	if(ipc->next)
		ipc->next->prev = ipc->prev;
	ipc->prev = ipc->next = NULL;
	return 0;
}

static int isdn_ppp_set_compressor(struct ippp_struct *is, struct isdn_ppp_comp_data *data)
{
	struct isdn_ppp_compressor *ipc = ipc_head;
	int ret;
	void *stat;
	int num = data->num;

	if(is->debug & 0x10)
		printk(KERN_DEBUG "[%d] Set %s type %d\n",is->unit,
			(data->flags&IPPP_COMP_FLAG_XMIT)?"compressor":"decompressor",num);

	/* If is has no valid reset state vector, we cannot allocate a
	   decompressor. The decompressor would cause reset transactions
	   sooner or later, and they need that vector. */

	if(!(data->flags & IPPP_COMP_FLAG_XMIT) && !is->reset) {
		printk(KERN_ERR "ippp_ccp: no reset data structure - can't"
		       " allow decompression.\n");
		return -ENOMEM;
	}

	while(ipc) {
		if(ipc->num == num) {
			stat = ipc->alloc(data);
			if(stat) {
				ret = ipc->init(stat,data,is->unit,0);
				if(!ret) {
					printk(KERN_ERR "Can't init (de)compression!\n");
					ipc->free(stat);
					stat = NULL;
					break;
				}
			}
			else {
				printk(KERN_ERR "Can't alloc (de)compression!\n");
				break;
			}

                        if(data->flags & IPPP_COMP_FLAG_XMIT) {
				if(data->flags & IPPP_COMP_FLAG_LINK) {
					if(is->link_comp_stat)
						is->link_compressor->free(is->link_comp_stat);
					is->link_comp_stat = stat;
                                	is->link_compressor = ipc;
				}
				else {
					if(is->comp_stat)
						is->compressor->free(is->comp_stat);
					is->comp_stat = stat;
                                	is->compressor = ipc;
				}
			}
                        else {
				if(data->flags & IPPP_COMP_FLAG_LINK) {
					if(is->link_decomp_stat)
						is->link_decompressor->free(is->link_decomp_stat);
					is->link_decomp_stat = stat;
        	                        is->link_decompressor = ipc;
				}
				else {
					if(is->decomp_stat)
						is->decompressor->free(is->decomp_stat);
					is->decomp_stat = stat;
        	                        is->decompressor = ipc;
				}
			}
			return 0;
		}
		ipc = ipc->next;
	}
	return -EINVAL;
}
