[net-next-2.6.git] / net / atm / pppoatm.c

/* net/atm/pppoatm.c - RFC2364 PPP over ATM/AAL5 */

/* Copyright 1999-2000 by Mitchell Blank Jr */
/* Based on clip.c; 1995-1999 by Werner Almesberger, EPFL LRC/ICA */
/* And on ppp_async.c; Copyright 1999 Paul Mackerras */
/* And help from Jens Axboe */

/*
 *  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 of the License, or (at your option) any later version.
 *
 * This driver provides the encapsulation and framing for sending
 * and receiving PPP frames in ATM AAL5 PDUs.
 */

/*
 * One shortcoming of this driver is that it does not comply with
 * section 8 of RFC2364 - we are supposed to detect a change
 * in encapsulation and immediately abort the connection (in order
 * to avoid a black-hole being created if our peer loses state
 * and changes encapsulation unilaterally.  However, since the
 * ppp_generic layer actually does the decapsulation, we need
 * a way of notifying it when we _think_ there might be a problem)
 * There's two cases:
 *   1.	LLC-encapsulation was missing when it was enabled.  In
 *	this case, we should tell the upper layer "tear down
 *	this session if this skb looks ok to you"
 *   2.	LLC-encapsulation was present when it was disabled.  Then
 *	we need to tell the upper layer "this packet may be
 *	ok, but if its in error tear down the session"
 * These hooks are not yet available in ppp_generic
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

#include <linux/module.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/capability.h>
#include <linux/ppp_defs.h>
#include <linux/if_ppp.h>
#include <linux/ppp_channel.h>
#include <linux/atmppp.h>

#include "common.h"

enum pppoatm_encaps {
	e_autodetect = PPPOATM_ENCAPS_AUTODETECT,
	e_vc = PPPOATM_ENCAPS_VC,
	e_llc = PPPOATM_ENCAPS_LLC,
};

struct pppoatm_vcc {
	struct atm_vcc	*atmvcc;	/* VCC descriptor */
	void (*old_push)(struct atm_vcc *, struct sk_buff *);
	void (*old_pop)(struct atm_vcc *, struct sk_buff *);
					/* keep old push/pop for detaching */
	enum pppoatm_encaps encaps;
	int flags;			/* SC_COMP_PROT - compress protocol */
	struct ppp_channel chan;	/* interface to generic ppp layer */
	struct tasklet_struct wakeup_tasklet;
};

/*
 * Header used for LLC Encapsulated PPP (4 bytes) followed by the LCP protocol
 * ID (0xC021) used in autodetection
 */
static const unsigned char pppllc[6] = { 0xFE, 0xFE, 0x03, 0xCF, 0xC0, 0x21 };
#define LLC_LEN		(4)

static inline struct pppoatm_vcc *atmvcc_to_pvcc(const struct atm_vcc *atmvcc)
{
	return (struct pppoatm_vcc *) (atmvcc->user_back);
}

static inline struct pppoatm_vcc *chan_to_pvcc(const struct ppp_channel *chan)
{
	return (struct pppoatm_vcc *) (chan->private);
}

/*
 * We can't do this directly from our _pop handler, since the ppp code
 * doesn't want to be called in interrupt context, so we do it from
 * a tasklet
 */
static void pppoatm_wakeup_sender(unsigned long arg)
{
	ppp_output_wakeup((struct ppp_channel *) arg);
}

/*
 * This gets called every time the ATM card has finished sending our
 * skb.  The ->old_pop will take care up normal atm flow control,
 * but we also need to wake up the device if we blocked it
 */
static void pppoatm_pop(struct atm_vcc *atmvcc, struct sk_buff *skb)
{
	struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
	pvcc->old_pop(atmvcc, skb);
	/*
	 * We don't really always want to do this since it's
	 * really inefficient - it would be much better if we could
	 * test if we had actually throttled the generic layer.
	 * Unfortunately then there would be a nasty SMP race where
	 * we could clear that flag just as we refuse another packet.
	 * For now we do the safe thing.
	 */
	tasklet_schedule(&pvcc->wakeup_tasklet);
}

/*
 * Unbind from PPP - currently we only do this when closing the socket,
 * but we could put this into an ioctl if need be
 */
static void pppoatm_unassign_vcc(struct atm_vcc *atmvcc)
{
	struct pppoatm_vcc *pvcc;
	pvcc = atmvcc_to_pvcc(atmvcc);
	atmvcc->push = pvcc->old_push;
	atmvcc->pop = pvcc->old_pop;
	tasklet_kill(&pvcc->wakeup_tasklet);
	ppp_unregister_channel(&pvcc->chan);
	atmvcc->user_back = NULL;
	kfree(pvcc);
	/* Gee, I hope we have the big kernel lock here... */
	module_put(THIS_MODULE);
}

/* Called when an AAL5 PDU comes in */
static void pppoatm_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
{
	struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
	pr_debug("\n");
	if (skb == NULL) {			/* VCC was closed */
		pr_debug("removing ATMPPP VCC %p\n", pvcc);
		pppoatm_unassign_vcc(atmvcc);
		atmvcc->push(atmvcc, NULL);	/* Pass along bad news */
		return;
	}
	atm_return(atmvcc, skb->truesize);
	switch (pvcc->encaps) {
	case e_llc:
		if (skb->len < LLC_LEN ||
		    memcmp(skb->data, pppllc, LLC_LEN))
			goto error;
		skb_pull(skb, LLC_LEN);
		break;
	case e_autodetect:
		if (pvcc->chan.ppp == NULL) {	/* Not bound yet! */
			kfree_skb(skb);
			return;
		}
		if (skb->len >= sizeof(pppllc) &&
		    !memcmp(skb->data, pppllc, sizeof(pppllc))) {
			pvcc->encaps = e_llc;
			skb_pull(skb, LLC_LEN);
			break;
		}
		if (skb->len >= (sizeof(pppllc) - LLC_LEN) &&
		    !memcmp(skb->data, &pppllc[LLC_LEN],
		    sizeof(pppllc) - LLC_LEN)) {
			pvcc->encaps = e_vc;
			pvcc->chan.mtu += LLC_LEN;
			break;
		}
		pr_debug("Couldn't autodetect yet (skb: %02X %02X %02X %02X %02X %02X)\n",
			 skb->data[0], skb->data[1], skb->data[2],
			 skb->data[3], skb->data[4], skb->data[5]);
		goto error;
	case e_vc:
		break;
	}
	ppp_input(&pvcc->chan, skb);
	return;

error:
	kfree_skb(skb);
	ppp_input_error(&pvcc->chan, 0);
}

/*
 * Called by the ppp_generic.c to send a packet - returns true if packet
 * was accepted.  If we return false, then it's our job to call
 * ppp_output_wakeup(chan) when we're feeling more up to it.
 * Note that in the ENOMEM case (as opposed to the !atm_may_send case)
 * we should really drop the packet, but the generic layer doesn't
 * support this yet.  We just return 'DROP_PACKET' which we actually define
 * as success, just to be clear what we're really doing.
 */
#define DROP_PACKET 1
static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
{
	struct pppoatm_vcc *pvcc = chan_to_pvcc(chan);
	ATM_SKB(skb)->vcc = pvcc->atmvcc;
	pr_debug("(skb=0x%p, vcc=0x%p)\n", skb, pvcc->atmvcc);
	if (skb->data[0] == '\0' && (pvcc->flags & SC_COMP_PROT))
		(void) skb_pull(skb, 1);
	switch (pvcc->encaps) {		/* LLC encapsulation needed */
	case e_llc:
		if (skb_headroom(skb) < LLC_LEN) {
			struct sk_buff *n;
			n = skb_realloc_headroom(skb, LLC_LEN);
			if (n != NULL &&
			    !atm_may_send(pvcc->atmvcc, n->truesize)) {
				kfree_skb(n);
				goto nospace;
			}
			kfree_skb(skb);
			skb = n;
			if (skb == NULL)
				return DROP_PACKET;
		} else if (!atm_may_send(pvcc->atmvcc, skb->truesize))
			goto nospace;
		memcpy(skb_push(skb, LLC_LEN), pppllc, LLC_LEN);
		break;
	case e_vc:
		if (!atm_may_send(pvcc->atmvcc, skb->truesize))
			goto nospace;
		break;
	case e_autodetect:
		pr_debug("Trying to send without setting encaps!\n");
		kfree_skb(skb);
		return 1;
	}

	atomic_add(skb->truesize, &sk_atm(ATM_SKB(skb)->vcc)->sk_wmem_alloc);
	ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options;
	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n",
		 skb, ATM_SKB(skb)->vcc, ATM_SKB(skb)->vcc->dev);
	return ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb)
	    ? DROP_PACKET : 1;
nospace:
	/*
	 * We don't have space to send this SKB now, but we might have
	 * already applied SC_COMP_PROT compression, so may need to undo
	 */
	if ((pvcc->flags & SC_COMP_PROT) && skb_headroom(skb) > 0 &&
	    skb->data[-1] == '\0')
		(void) skb_push(skb, 1);
	return 0;
}

/* This handles ioctls sent to the /dev/ppp interface */
static int pppoatm_devppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
	unsigned long arg)
{
	switch (cmd) {
	case PPPIOCGFLAGS:
		return put_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
		    ? -EFAULT : 0;
	case PPPIOCSFLAGS:
		return get_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
		    ? -EFAULT : 0;
	}
	return -ENOTTY;
}

static const struct ppp_channel_ops pppoatm_ops = {
	.start_xmit = pppoatm_send,
	.ioctl = pppoatm_devppp_ioctl,
};

static int pppoatm_assign_vcc(struct atm_vcc *atmvcc, void __user *arg)
{
	struct atm_backend_ppp be;
	struct pppoatm_vcc *pvcc;
	int err;
	/*
	 * Each PPPoATM instance has its own tasklet - this is just a
	 * prototypical one used to initialize them
	 */
	static const DECLARE_TASKLET(tasklet_proto, pppoatm_wakeup_sender, 0);
	if (copy_from_user(&be, arg, sizeof be))
		return -EFAULT;
	if (be.encaps != PPPOATM_ENCAPS_AUTODETECT &&
	    be.encaps != PPPOATM_ENCAPS_VC && be.encaps != PPPOATM_ENCAPS_LLC)
		return -EINVAL;
	pvcc = kzalloc(sizeof(*pvcc), GFP_KERNEL);
	if (pvcc == NULL)
		return -ENOMEM;
	pvcc->atmvcc = atmvcc;
	pvcc->old_push = atmvcc->push;
	pvcc->old_pop = atmvcc->pop;
	pvcc->encaps = (enum pppoatm_encaps) be.encaps;
	pvcc->chan.private = pvcc;
	pvcc->chan.ops = &pppoatm_ops;
	pvcc->chan.mtu = atmvcc->qos.txtp.max_sdu - PPP_HDRLEN -
	    (be.encaps == e_vc ? 0 : LLC_LEN);
	pvcc->wakeup_tasklet = tasklet_proto;
	pvcc->wakeup_tasklet.data = (unsigned long) &pvcc->chan;
	err = ppp_register_channel(&pvcc->chan);
	if (err != 0) {
		kfree(pvcc);
		return err;
	}
	atmvcc->user_back = pvcc;
	atmvcc->push = pppoatm_push;
	atmvcc->pop = pppoatm_pop;
	__module_get(THIS_MODULE);
	return 0;
}

/*
 * This handles ioctls actually performed on our vcc - we must return
 * -ENOIOCTLCMD for any unrecognized ioctl
 */
static int pppoatm_ioctl(struct socket *sock, unsigned int cmd,
	unsigned long arg)
{
	struct atm_vcc *atmvcc = ATM_SD(sock);
	void __user *argp = (void __user *)arg;

	if (cmd != ATM_SETBACKEND && atmvcc->push != pppoatm_push)
		return -ENOIOCTLCMD;
	switch (cmd) {
	case ATM_SETBACKEND: {
		atm_backend_t b;
		if (get_user(b, (atm_backend_t __user *) argp))
			return -EFAULT;
		if (b != ATM_BACKEND_PPP)
			return -ENOIOCTLCMD;
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		return pppoatm_assign_vcc(atmvcc, argp);
		}
	case PPPIOCGCHAN:
		return put_user(ppp_channel_index(&atmvcc_to_pvcc(atmvcc)->
		    chan), (int __user *) argp) ? -EFAULT : 0;
	case PPPIOCGUNIT:
		return put_user(ppp_unit_number(&atmvcc_to_pvcc(atmvcc)->
		    chan), (int __user *) argp) ? -EFAULT : 0;
	}
	return -ENOIOCTLCMD;
}

static struct atm_ioctl pppoatm_ioctl_ops = {
	.owner	= THIS_MODULE,
	.ioctl	= pppoatm_ioctl,
};

static int __init pppoatm_init(void)
{
	register_atm_ioctl(&pppoatm_ioctl_ops);
	return 0;
}

static void __exit pppoatm_exit(void)
{
	deregister_atm_ioctl(&pppoatm_ioctl_ops);
}

module_init(pppoatm_init);
module_exit(pppoatm_exit);

MODULE_AUTHOR("Mitchell Blank Jr <mitch@sfgoth.com>");
MODULE_DESCRIPTION("RFC2364 PPP over ATM/AAL5");
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/* net/atm/pppoatm.c - RFC2364 PPP over ATM/AAL5 */
	2
	3	/* Copyright 1999-2000 by Mitchell Blank Jr */
	4	/* Based on clip.c; 1995-1999 by Werner Almesberger, EPFL LRC/ICA */
	5	/* And on ppp_async.c; Copyright 1999 Paul Mackerras */
	6	/* And help from Jens Axboe */
	7
	8	/*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* as published by the Free Software Foundation; either version
	12	* 2 of the License, or (at your option) any later version.
	13	*
	14	* This driver provides the encapsulation and framing for sending
	15	* and receiving PPP frames in ATM AAL5 PDUs.
	16	*/
	17
	18	/*
	19	* One shortcoming of this driver is that it does not comply with
	20	* section 8 of RFC2364 - we are supposed to detect a change
	21	* in encapsulation and immediately abort the connection (in order
	22	* to avoid a black-hole being created if our peer loses state
	23	* and changes encapsulation unilaterally. However, since the
	24	* ppp_generic layer actually does the decapsulation, we need
	25	* a way of notifying it when we _think_ there might be a problem)
	26	* There's two cases:
	27	* 1. LLC-encapsulation was missing when it was enabled. In
	28	* this case, we should tell the upper layer "tear down
	29	* this session if this skb looks ok to you"
	30	* 2. LLC-encapsulation was present when it was disabled. Then
	31	* we need to tell the upper layer "this packet may be
	32	* ok, but if its in error tear down the session"
	33	* These hooks are not yet available in ppp_generic
	34	*/
	35
99824461 JP	36	#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
99824461 JP	37
1da177e4	38	#include <linux/module.h>
1da177e4 LT	39	#include <linux/init.h>
1da177e4 LT	40	#include <linux/skbuff.h>
5a0e3ad6	41	#include <linux/slab.h>
1da177e4 LT	42	#include <linux/atm.h>
1da177e4 LT	43	#include <linux/atmdev.h>
4fc268d2	44	#include <linux/capability.h>
1da177e4 LT	45	#include <linux/ppp_defs.h>
	46	#include <linux/if_ppp.h>
	47	#include <linux/ppp_channel.h>
	48	#include <linux/atmppp.h>
	49
	50	#include "common.h"
	51
1da177e4 LT	52	enum pppoatm_encaps {
	53	e_autodetect = PPPOATM_ENCAPS_AUTODETECT,
	54	e_vc = PPPOATM_ENCAPS_VC,
	55	e_llc = PPPOATM_ENCAPS_LLC,
	56	};
	57
	58	struct pppoatm_vcc {
	59	struct atm_vcc atmvcc; / VCC descriptor */
	60	void (old_push)(struct atm_vcc , struct sk_buff *);
	61	void (old_pop)(struct atm_vcc , struct sk_buff *);
	62	/* keep old push/pop for detaching */
	63	enum pppoatm_encaps encaps;
	64	int flags; /* SC_COMP_PROT - compress protocol */
	65	struct ppp_channel chan; /* interface to generic ppp layer */
	66	struct tasklet_struct wakeup_tasklet;
	67	};
	68
	69	/*
	70	* Header used for LLC Encapsulated PPP (4 bytes) followed by the LCP protocol
	71	* ID (0xC021) used in autodetection
	72	*/
	73	static const unsigned char pppllc[6] = { 0xFE, 0xFE, 0x03, 0xCF, 0xC0, 0x21 };
	74	#define LLC_LEN (4)
	75
	76	static inline struct pppoatm_vcc atmvcc_to_pvcc(const struct atm_vcc atmvcc)
	77	{
	78	return (struct pppoatm_vcc *) (atmvcc->user_back);
	79	}
	80
	81	static inline struct pppoatm_vcc chan_to_pvcc(const struct ppp_channel chan)
	82	{
	83	return (struct pppoatm_vcc *) (chan->private);
	84	}
	85
	86	/*
	87	* We can't do this directly from our _pop handler, since the ppp code
	88	* doesn't want to be called in interrupt context, so we do it from
	89	* a tasklet
	90	*/
	91	static void pppoatm_wakeup_sender(unsigned long arg)
	92	{
	93	ppp_output_wakeup((struct ppp_channel *) arg);
	94	}
	95
	96	/*
	97	* This gets called every time the ATM card has finished sending our
	98	* skb. The ->old_pop will take care up normal atm flow control,
	99	* but we also need to wake up the device if we blocked it
	100	*/
	101	static void pppoatm_pop(struct atm_vcc atmvcc, struct sk_buff skb)
	102	{
	103	struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
	104	pvcc->old_pop(atmvcc, skb);
	105	/*
	106	* We don't really always want to do this since it's
	107	* really inefficient - it would be much better if we could
	108	* test if we had actually throttled the generic layer.
	109	* Unfortunately then there would be a nasty SMP race where
	110	* we could clear that flag just as we refuse another packet.
	111	* For now we do the safe thing.
	112	*/
	113	tasklet_schedule(&pvcc->wakeup_tasklet);
	114	}
	115
116	/*
117	* Unbind from PPP - currently we only do this when closing the socket,
118	* but we could put this into an ioctl if need be
119	*/
120	static void pppoatm_unassign_vcc(struct atm_vcc *atmvcc)
121	{
122	struct pppoatm_vcc *pvcc;
123	pvcc = atmvcc_to_pvcc(atmvcc);
124	atmvcc->push = pvcc->old_push;
125	atmvcc->pop = pvcc->old_pop;
126	tasklet_kill(&pvcc->wakeup_tasklet);
127	ppp_unregister_channel(&pvcc->chan);
128	atmvcc->user_back = NULL;
129	kfree(pvcc);
130	/* Gee, I hope we have the big kernel lock here... */
131	module_put(THIS_MODULE);
132	}
133
134	/* Called when an AAL5 PDU comes in */
135	static void pppoatm_push(struct atm_vcc atmvcc, struct sk_buff skb)
136	{
137	struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
99824461	138	pr_debug("\n");
1da177e4	139	if (skb == NULL) { /* VCC was closed */
52240062	140	pr_debug("removing ATMPPP VCC %p\n", pvcc);
1da177e4 LT	141	pppoatm_unassign_vcc(atmvcc);
	142	atmvcc->push(atmvcc, NULL); /* Pass along bad news */
	143	return;
	144	}
	145	atm_return(atmvcc, skb->truesize);
	146	switch (pvcc->encaps) {
	147	case e_llc:
	148	if (skb->len < LLC_LEN \|\|
	149	memcmp(skb->data, pppllc, LLC_LEN))
	150	goto error;
	151	skb_pull(skb, LLC_LEN);
	152	break;
	153	case e_autodetect:
	154	if (pvcc->chan.ppp == NULL) { /* Not bound yet! */
	155	kfree_skb(skb);
	156	return;
	157	}
	158	if (skb->len >= sizeof(pppllc) &&
	159	!memcmp(skb->data, pppllc, sizeof(pppllc))) {
	160	pvcc->encaps = e_llc;
	161	skb_pull(skb, LLC_LEN);
	162	break;
	163	}
	164	if (skb->len >= (sizeof(pppllc) - LLC_LEN) &&
	165	!memcmp(skb->data, &pppllc[LLC_LEN],
	166	sizeof(pppllc) - LLC_LEN)) {
	167	pvcc->encaps = e_vc;
	168	pvcc->chan.mtu += LLC_LEN;
	169	break;
	170	}
99824461 JP	171	pr_debug("Couldn't autodetect yet (skb: %02X %02X %02X %02X %02X %02X)\n",
	172	skb->data[0], skb->data[1], skb->data[2],
	173	skb->data[3], skb->data[4], skb->data[5]);
1da177e4 LT	174	goto error;
	175	case e_vc:
	176	break;
	177	}
	178	ppp_input(&pvcc->chan, skb);
	179	return;
d81219db JP	180
d81219db JP	181	error:
1da177e4 LT	182	kfree_skb(skb);
	183	ppp_input_error(&pvcc->chan, 0);
	184	}
	185
	186	/*
	187	* Called by the ppp_generic.c to send a packet - returns true if packet
	188	* was accepted. If we return false, then it's our job to call
	189	* ppp_output_wakeup(chan) when we're feeling more up to it.
	190	* Note that in the ENOMEM case (as opposed to the !atm_may_send case)
	191	* we should really drop the packet, but the generic layer doesn't
	192	* support this yet. We just return 'DROP_PACKET' which we actually define
	193	* as success, just to be clear what we're really doing.
	194	*/
	195	#define DROP_PACKET 1
	196	static int pppoatm_send(struct ppp_channel chan, struct sk_buff skb)
	197	{
	198	struct pppoatm_vcc *pvcc = chan_to_pvcc(chan);
	199	ATM_SKB(skb)->vcc = pvcc->atmvcc;
99824461	200	pr_debug("(skb=0x%p, vcc=0x%p)\n", skb, pvcc->atmvcc);
1da177e4 LT	201	if (skb->data[0] == '\0' && (pvcc->flags & SC_COMP_PROT))
	202	(void) skb_pull(skb, 1);
	203	switch (pvcc->encaps) { /* LLC encapsulation needed */
	204	case e_llc:
	205	if (skb_headroom(skb) < LLC_LEN) {
	206	struct sk_buff *n;
	207	n = skb_realloc_headroom(skb, LLC_LEN);
	208	if (n != NULL &&
	209	!atm_may_send(pvcc->atmvcc, n->truesize)) {
	210	kfree_skb(n);
	211	goto nospace;
	212	}
	213	kfree_skb(skb);
d81219db JP	214	skb = n;
d81219db JP	215	if (skb == NULL)
1da177e4 LT	216	return DROP_PACKET;
	217	} else if (!atm_may_send(pvcc->atmvcc, skb->truesize))
	218	goto nospace;
	219	memcpy(skb_push(skb, LLC_LEN), pppllc, LLC_LEN);
	220	break;
	221	case e_vc:
	222	if (!atm_may_send(pvcc->atmvcc, skb->truesize))
	223	goto nospace;
	224	break;
	225	case e_autodetect:
52240062	226	pr_debug("Trying to send without setting encaps!\n");
1da177e4 LT	227	kfree_skb(skb);
	228	return 1;
	229	}
	230
	231	atomic_add(skb->truesize, &sk_atm(ATM_SKB(skb)->vcc)->sk_wmem_alloc);
	232	ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options;
99824461 JP	233	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n",
99824461 JP	234	skb, ATM_SKB(skb)->vcc, ATM_SKB(skb)->vcc->dev);
1da177e4 LT	235	return ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb)
1da177e4 LT	236	? DROP_PACKET : 1;
d81219db	237	nospace:
1da177e4 LT	238	/*
	239	* We don't have space to send this SKB now, but we might have
	240	* already applied SC_COMP_PROT compression, so may need to undo
	241	*/
	242	if ((pvcc->flags & SC_COMP_PROT) && skb_headroom(skb) > 0 &&
	243	skb->data[-1] == '\0')
	244	(void) skb_push(skb, 1);
	245	return 0;
	246	}
	247
	248	/* This handles ioctls sent to the /dev/ppp interface */
	249	static int pppoatm_devppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
	250	unsigned long arg)
	251	{
	252	switch (cmd) {
	253	case PPPIOCGFLAGS:
	254	return put_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
	255	? -EFAULT : 0;
	256	case PPPIOCSFLAGS:
	257	return get_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
	258	? -EFAULT : 0;
	259	}
	260	return -ENOTTY;
	261	}
	262
d7100da0	263	static const struct ppp_channel_ops pppoatm_ops = {
1da177e4 LT	264	.start_xmit = pppoatm_send,
	265	.ioctl = pppoatm_devppp_ioctl,
	266	};
	267
	268	static int pppoatm_assign_vcc(struct atm_vcc atmvcc, void __user arg)
	269	{
	270	struct atm_backend_ppp be;
	271	struct pppoatm_vcc *pvcc;
	272	int err;
	273	/*
	274	* Each PPPoATM instance has its own tasklet - this is just a
	275	* prototypical one used to initialize them
	276	*/
	277	static const DECLARE_TASKLET(tasklet_proto, pppoatm_wakeup_sender, 0);
	278	if (copy_from_user(&be, arg, sizeof be))
	279	return -EFAULT;
	280	if (be.encaps != PPPOATM_ENCAPS_AUTODETECT &&
	281	be.encaps != PPPOATM_ENCAPS_VC && be.encaps != PPPOATM_ENCAPS_LLC)
	282	return -EINVAL;
0da974f4	283	pvcc = kzalloc(sizeof(*pvcc), GFP_KERNEL);
1da177e4 LT	284	if (pvcc == NULL)
1da177e4 LT	285	return -ENOMEM;
1da177e4 LT	286	pvcc->atmvcc = atmvcc;
	287	pvcc->old_push = atmvcc->push;
	288	pvcc->old_pop = atmvcc->pop;
	289	pvcc->encaps = (enum pppoatm_encaps) be.encaps;
	290	pvcc->chan.private = pvcc;
	291	pvcc->chan.ops = &pppoatm_ops;
	292	pvcc->chan.mtu = atmvcc->qos.txtp.max_sdu - PPP_HDRLEN -
	293	(be.encaps == e_vc ? 0 : LLC_LEN);
	294	pvcc->wakeup_tasklet = tasklet_proto;
	295	pvcc->wakeup_tasklet.data = (unsigned long) &pvcc->chan;
d81219db JP	296	err = ppp_register_channel(&pvcc->chan);
d81219db JP	297	if (err != 0) {
1da177e4 LT	298	kfree(pvcc);
	299	return err;
	300	}
	301	atmvcc->user_back = pvcc;
	302	atmvcc->push = pppoatm_push;
	303	atmvcc->pop = pppoatm_pop;
	304	__module_get(THIS_MODULE);
	305	return 0;
	306	}
	307
	308	/*
	309	* This handles ioctls actually performed on our vcc - we must return
	310	* -ENOIOCTLCMD for any unrecognized ioctl
	311	*/
	312	static int pppoatm_ioctl(struct socket *sock, unsigned int cmd,
	313	unsigned long arg)
	314	{
	315	struct atm_vcc *atmvcc = ATM_SD(sock);
	316	void __user argp = (void __user )arg;
	317
	318	if (cmd != ATM_SETBACKEND && atmvcc->push != pppoatm_push)
	319	return -ENOIOCTLCMD;
	320	switch (cmd) {
	321	case ATM_SETBACKEND: {
	322	atm_backend_t b;
	323	if (get_user(b, (atm_backend_t __user *) argp))
	324	return -EFAULT;
	325	if (b != ATM_BACKEND_PPP)
	326	return -ENOIOCTLCMD;
	327	if (!capable(CAP_NET_ADMIN))
	328	return -EPERM;
	329	return pppoatm_assign_vcc(atmvcc, argp);
	330	}
	331	case PPPIOCGCHAN:
	332	return put_user(ppp_channel_index(&atmvcc_to_pvcc(atmvcc)->
	333	chan), (int __user *) argp) ? -EFAULT : 0;
	334	case PPPIOCGUNIT:
	335	return put_user(ppp_unit_number(&atmvcc_to_pvcc(atmvcc)->
	336	chan), (int __user *) argp) ? -EFAULT : 0;
	337	}
	338	return -ENOIOCTLCMD;
	339	}
	340
	341	static struct atm_ioctl pppoatm_ioctl_ops = {
	342	.owner = THIS_MODULE,
	343	.ioctl = pppoatm_ioctl,
	344	};
	345
	346	static int __init pppoatm_init(void)
	347	{
	348	register_atm_ioctl(&pppoatm_ioctl_ops);
	349	return 0;
	350	}
	351
	352	static void __exit pppoatm_exit(void)
	353	{
	354	deregister_atm_ioctl(&pppoatm_ioctl_ops);
	355	}
	356
	357	module_init(pppoatm_init);
	358	module_exit(pppoatm_exit);
	359
	360	MODULE_AUTHOR("Mitchell Blank Jr <mitch@sfgoth.com>");
	361	MODULE_DESCRIPTION("RFC2364 PPP over ATM/AAL5");
362	MODULE_LICENSE("GPL");