ppp_generic.c 67.9 KB
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/*
 * Generic PPP layer for Linux.
 *
 * Copyright 1999-2002 Paul Mackerras.
 *
 *  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.
 *
 * The generic PPP layer handles the PPP network interfaces, the
 * /dev/ppp device, packet and VJ compression, and multilink.
 * It talks to PPP `channels' via the interface defined in
 * include/linux/ppp_channel.h.  Channels provide the basic means for
 * sending and receiving PPP frames on some kind of communications
 * channel.
 *
 * Part of the code in this driver was inspired by the old async-only
 * PPP driver, written by Michael Callahan and Al Longyear, and
 * subsequently hacked by Paul Mackerras.
 *
 * ==FILEVERSION 20041108==
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/list.h>
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#include <linux/idr.h>
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#include <linux/netdevice.h>
#include <linux/poll.h>
#include <linux/ppp_defs.h>
#include <linux/filter.h>
#include <linux/if_ppp.h>
#include <linux/ppp_channel.h>
#include <linux/ppp-comp.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/if_arp.h>
#include <linux/ip.h>
#include <linux/tcp.h>
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#include <linux/smp_lock.h>
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#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/stddef.h>
#include <linux/device.h>
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#include <linux/mutex.h>
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#include <net/slhc_vj.h>
#include <asm/atomic.h>

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#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

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#define PPP_VERSION	"2.4.2"

/*
 * Network protocols we support.
 */
#define NP_IP	0		/* Internet Protocol V4 */
#define NP_IPV6	1		/* Internet Protocol V6 */
#define NP_IPX	2		/* IPX protocol */
#define NP_AT	3		/* Appletalk protocol */
#define NP_MPLS_UC 4		/* MPLS unicast */
#define NP_MPLS_MC 5		/* MPLS multicast */
#define NUM_NP	6		/* Number of NPs. */

#define MPHDRLEN	6	/* multilink protocol header length */
#define MPHDRLEN_SSN	4	/* ditto with short sequence numbers */
#define MIN_FRAG_SIZE	64

/*
 * An instance of /dev/ppp can be associated with either a ppp
 * interface unit or a ppp channel.  In both cases, file->private_data
 * points to one of these.
 */
struct ppp_file {
	enum {
		INTERFACE=1, CHANNEL
	}		kind;
	struct sk_buff_head xq;		/* pppd transmit queue */
	struct sk_buff_head rq;		/* receive queue for pppd */
	wait_queue_head_t rwait;	/* for poll on reading /dev/ppp */
	atomic_t	refcnt;		/* # refs (incl /dev/ppp attached) */
	int		hdrlen;		/* space to leave for headers */
	int		index;		/* interface unit / channel number */
	int		dead;		/* unit/channel has been shut down */
};

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#define PF_TO_X(pf, X)		container_of(pf, X, file)
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#define PF_TO_PPP(pf)		PF_TO_X(pf, struct ppp)
#define PF_TO_CHANNEL(pf)	PF_TO_X(pf, struct channel)

/*
 * Data structure describing one ppp unit.
 * A ppp unit corresponds to a ppp network interface device
 * and represents a multilink bundle.
 * It can have 0 or more ppp channels connected to it.
 */
struct ppp {
	struct ppp_file	file;		/* stuff for read/write/poll 0 */
	struct file	*owner;		/* file that owns this unit 48 */
	struct list_head channels;	/* list of attached channels 4c */
	int		n_channels;	/* how many channels are attached 54 */
	spinlock_t	rlock;		/* lock for receive side 58 */
	spinlock_t	wlock;		/* lock for transmit side 5c */
	int		mru;		/* max receive unit 60 */
	unsigned int	flags;		/* control bits 64 */
	unsigned int	xstate;		/* transmit state bits 68 */
	unsigned int	rstate;		/* receive state bits 6c */
	int		debug;		/* debug flags 70 */
	struct slcompress *vj;		/* state for VJ header compression */
	enum NPmode	npmode[NUM_NP];	/* what to do with each net proto 78 */
	struct sk_buff	*xmit_pending;	/* a packet ready to go out 88 */
	struct compressor *xcomp;	/* transmit packet compressor 8c */
	void		*xc_state;	/* its internal state 90 */
	struct compressor *rcomp;	/* receive decompressor 94 */
	void		*rc_state;	/* its internal state 98 */
	unsigned long	last_xmit;	/* jiffies when last pkt sent 9c */
	unsigned long	last_recv;	/* jiffies when last pkt rcvd a0 */
	struct net_device *dev;		/* network interface device a4 */
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	int		closing;	/* is device closing down? a8 */
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#ifdef CONFIG_PPP_MULTILINK
	int		nxchan;		/* next channel to send something on */
	u32		nxseq;		/* next sequence number to send */
	int		mrru;		/* MP: max reconst. receive unit */
	u32		nextseq;	/* MP: seq no of next packet */
	u32		minseq;		/* MP: min of most recent seqnos */
	struct sk_buff_head mrq;	/* MP: receive reconstruction queue */
#endif /* CONFIG_PPP_MULTILINK */
#ifdef CONFIG_PPP_FILTER
	struct sock_filter *pass_filter;	/* filter for packets to pass */
	struct sock_filter *active_filter;/* filter for pkts to reset idle */
	unsigned pass_len, active_len;
#endif /* CONFIG_PPP_FILTER */
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	struct net	*ppp_net;	/* the net we belong to */
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};

/*
 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
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 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 * SC_MUST_COMP
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 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 * Bits in xstate: SC_COMP_RUN
 */
#define SC_FLAG_BITS	(SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
			 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
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			 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
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/*
 * Private data structure for each channel.
 * This includes the data structure used for multilink.
 */
struct channel {
	struct ppp_file	file;		/* stuff for read/write/poll */
	struct list_head list;		/* link in all/new_channels list */
	struct ppp_channel *chan;	/* public channel data structure */
	struct rw_semaphore chan_sem;	/* protects `chan' during chan ioctl */
	spinlock_t	downl;		/* protects `chan', file.xq dequeue */
	struct ppp	*ppp;		/* ppp unit we're connected to */
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	struct net	*chan_net;	/* the net channel belongs to */
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	struct list_head clist;		/* link in list of channels per unit */
	rwlock_t	upl;		/* protects `ppp' */
#ifdef CONFIG_PPP_MULTILINK
	u8		avail;		/* flag used in multilink stuff */
	u8		had_frag;	/* >= 1 fragments have been sent */
	u32		lastseq;	/* MP: last sequence # received */
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	int     speed;		/* speed of the corresponding ppp channel*/
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#endif /* CONFIG_PPP_MULTILINK */
};

/*
 * SMP locking issues:
 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 * list and the ppp.n_channels field, you need to take both locks
 * before you modify them.
 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 * channel.downl.
 */

static atomic_t ppp_unit_count = ATOMIC_INIT(0);
static atomic_t channel_count = ATOMIC_INIT(0);

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/* per-net private data for this module */
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static int ppp_net_id;
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struct ppp_net {
	/* units to ppp mapping */
	struct idr units_idr;

	/*
	 * all_ppp_mutex protects the units_idr mapping.
	 * It also ensures that finding a ppp unit in the units_idr
	 * map and updating its file.refcnt field is atomic.
	 */
	struct mutex all_ppp_mutex;

	/* channels */
	struct list_head all_channels;
	struct list_head new_channels;
	int last_channel_index;

	/*
	 * all_channels_lock protects all_channels and
	 * last_channel_index, and the atomicity of find
	 * a channel and updating its file.refcnt field.
	 */
	spinlock_t all_channels_lock;
};

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/* Get the PPP protocol number from a skb */
#define PPP_PROTO(skb)	(((skb)->data[0] << 8) + (skb)->data[1])

/* We limit the length of ppp->file.rq to this (arbitrary) value */
#define PPP_MAX_RQLEN	32

/*
 * Maximum number of multilink fragments queued up.
 * This has to be large enough to cope with the maximum latency of
 * the slowest channel relative to the others.  Strictly it should
 * depend on the number of channels and their characteristics.
 */
#define PPP_MP_MAX_QLEN	128

/* Multilink header bits. */
#define B	0x80		/* this fragment begins a packet */
#define E	0x40		/* this fragment ends a packet */

/* Compare multilink sequence numbers (assumed to be 32 bits wide) */
#define seq_before(a, b)	((s32)((a) - (b)) < 0)
#define seq_after(a, b)		((s32)((a) - (b)) > 0)

/* Prototypes. */
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static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
			struct file *file, unsigned int cmd, unsigned long arg);
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static void ppp_xmit_process(struct ppp *ppp);
static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
static void ppp_push(struct ppp *ppp);
static void ppp_channel_push(struct channel *pch);
static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
			      struct channel *pch);
static void ppp_receive_error(struct ppp *ppp);
static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
					    struct sk_buff *skb);
#ifdef CONFIG_PPP_MULTILINK
static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
				struct channel *pch);
static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
#endif /* CONFIG_PPP_MULTILINK */
static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
static void ppp_ccp_closed(struct ppp *ppp);
static struct compressor *find_compressor(int type);
static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
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static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
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static void init_ppp_file(struct ppp_file *pf, int kind);
static void ppp_shutdown_interface(struct ppp *ppp);
static void ppp_destroy_interface(struct ppp *ppp);
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static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
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static int ppp_connect_channel(struct channel *pch, int unit);
static int ppp_disconnect_channel(struct channel *pch);
static void ppp_destroy_channel(struct channel *pch);
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static int unit_get(struct idr *p, void *ptr);
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static int unit_set(struct idr *p, void *ptr, int n);
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static void unit_put(struct idr *p, int n);
static void *unit_find(struct idr *p, int n);
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static struct class *ppp_class;
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/* per net-namespace data */
static inline struct ppp_net *ppp_pernet(struct net *net)
{
	BUG_ON(!net);

	return net_generic(net, ppp_net_id);
}

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/* Translates a PPP protocol number to a NP index (NP == network protocol) */
static inline int proto_to_npindex(int proto)
{
	switch (proto) {
	case PPP_IP:
		return NP_IP;
	case PPP_IPV6:
		return NP_IPV6;
	case PPP_IPX:
		return NP_IPX;
	case PPP_AT:
		return NP_AT;
	case PPP_MPLS_UC:
		return NP_MPLS_UC;
	case PPP_MPLS_MC:
		return NP_MPLS_MC;
	}
	return -EINVAL;
}

/* Translates an NP index into a PPP protocol number */
static const int npindex_to_proto[NUM_NP] = {
	PPP_IP,
	PPP_IPV6,
	PPP_IPX,
	PPP_AT,
	PPP_MPLS_UC,
	PPP_MPLS_MC,
};
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/* Translates an ethertype into an NP index */
static inline int ethertype_to_npindex(int ethertype)
{
	switch (ethertype) {
	case ETH_P_IP:
		return NP_IP;
	case ETH_P_IPV6:
		return NP_IPV6;
	case ETH_P_IPX:
		return NP_IPX;
	case ETH_P_PPPTALK:
	case ETH_P_ATALK:
		return NP_AT;
	case ETH_P_MPLS_UC:
		return NP_MPLS_UC;
	case ETH_P_MPLS_MC:
		return NP_MPLS_MC;
	}
	return -1;
}

/* Translates an NP index into an ethertype */
static const int npindex_to_ethertype[NUM_NP] = {
	ETH_P_IP,
	ETH_P_IPV6,
	ETH_P_IPX,
	ETH_P_PPPTALK,
	ETH_P_MPLS_UC,
	ETH_P_MPLS_MC,
};

/*
 * Locking shorthand.
 */
#define ppp_xmit_lock(ppp)	spin_lock_bh(&(ppp)->wlock)
#define ppp_xmit_unlock(ppp)	spin_unlock_bh(&(ppp)->wlock)
#define ppp_recv_lock(ppp)	spin_lock_bh(&(ppp)->rlock)
#define ppp_recv_unlock(ppp)	spin_unlock_bh(&(ppp)->rlock)
#define ppp_lock(ppp)		do { ppp_xmit_lock(ppp); \
				     ppp_recv_lock(ppp); } while (0)
#define ppp_unlock(ppp)		do { ppp_recv_unlock(ppp); \
				     ppp_xmit_unlock(ppp); } while (0)

/*
 * /dev/ppp device routines.
 * The /dev/ppp device is used by pppd to control the ppp unit.
 * It supports the read, write, ioctl and poll functions.
 * Open instances of /dev/ppp can be in one of three states:
 * unattached, attached to a ppp unit, or attached to a ppp channel.
 */
static int ppp_open(struct inode *inode, struct file *file)
{
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	cycle_kernel_lock();
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	/*
	 * This could (should?) be enforced by the permissions on /dev/ppp.
	 */
	if (!capable(CAP_NET_ADMIN))
		return -EPERM;
	return 0;
}

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static int ppp_release(struct inode *unused, struct file *file)
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{
	struct ppp_file *pf = file->private_data;
	struct ppp *ppp;

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	if (pf) {
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		file->private_data = NULL;
		if (pf->kind == INTERFACE) {
			ppp = PF_TO_PPP(pf);
			if (file == ppp->owner)
				ppp_shutdown_interface(ppp);
		}
		if (atomic_dec_and_test(&pf->refcnt)) {
			switch (pf->kind) {
			case INTERFACE:
				ppp_destroy_interface(PF_TO_PPP(pf));
				break;
			case CHANNEL:
				ppp_destroy_channel(PF_TO_CHANNEL(pf));
				break;
			}
		}
	}
	return 0;
}

static ssize_t ppp_read(struct file *file, char __user *buf,
			size_t count, loff_t *ppos)
{
	struct ppp_file *pf = file->private_data;
	DECLARE_WAITQUEUE(wait, current);
	ssize_t ret;
	struct sk_buff *skb = NULL;

	ret = count;

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	if (!pf)
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		return -ENXIO;
	add_wait_queue(&pf->rwait, &wait);
	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		skb = skb_dequeue(&pf->rq);
		if (skb)
			break;
		ret = 0;
		if (pf->dead)
			break;
		if (pf->kind == INTERFACE) {
			/*
			 * Return 0 (EOF) on an interface that has no
			 * channels connected, unless it is looping
			 * network traffic (demand mode).
			 */
			struct ppp *ppp = PF_TO_PPP(pf);
			if (ppp->n_channels == 0
			    && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
				break;
		}
		ret = -EAGAIN;
		if (file->f_flags & O_NONBLOCK)
			break;
		ret = -ERESTARTSYS;
		if (signal_pending(current))
			break;
		schedule();
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&pf->rwait, &wait);

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	if (!skb)
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		goto out;

	ret = -EOVERFLOW;
	if (skb->len > count)
		goto outf;
	ret = -EFAULT;
	if (copy_to_user(buf, skb->data, skb->len))
		goto outf;
	ret = skb->len;

 outf:
	kfree_skb(skb);
 out:
	return ret;
}

static ssize_t ppp_write(struct file *file, const char __user *buf,
			 size_t count, loff_t *ppos)
{
	struct ppp_file *pf = file->private_data;
	struct sk_buff *skb;
	ssize_t ret;

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	if (!pf)
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		return -ENXIO;
	ret = -ENOMEM;
	skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
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	if (!skb)
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		goto out;
	skb_reserve(skb, pf->hdrlen);
	ret = -EFAULT;
	if (copy_from_user(skb_put(skb, count), buf, count)) {
		kfree_skb(skb);
		goto out;
	}

	skb_queue_tail(&pf->xq, skb);

	switch (pf->kind) {
	case INTERFACE:
		ppp_xmit_process(PF_TO_PPP(pf));
		break;
	case CHANNEL:
		ppp_channel_push(PF_TO_CHANNEL(pf));
		break;
	}

	ret = count;

 out:
	return ret;
}

/* No kernel lock - fine */
static unsigned int ppp_poll(struct file *file, poll_table *wait)
{
	struct ppp_file *pf = file->private_data;
	unsigned int mask;

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	if (!pf)
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		return 0;
	poll_wait(file, &pf->rwait, wait);
	mask = POLLOUT | POLLWRNORM;
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	if (skb_peek(&pf->rq))
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		mask |= POLLIN | POLLRDNORM;
	if (pf->dead)
		mask |= POLLHUP;
	else if (pf->kind == INTERFACE) {
		/* see comment in ppp_read */
		struct ppp *ppp = PF_TO_PPP(pf);
		if (ppp->n_channels == 0
		    && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
			mask |= POLLIN | POLLRDNORM;
	}

	return mask;
}

#ifdef CONFIG_PPP_FILTER
static int get_filter(void __user *arg, struct sock_filter **p)
{
	struct sock_fprog uprog;
	struct sock_filter *code = NULL;
	int len, err;

	if (copy_from_user(&uprog, arg, sizeof(uprog)))
		return -EFAULT;

	if (!uprog.len) {
		*p = NULL;
		return 0;
	}

	len = uprog.len * sizeof(struct sock_filter);
	code = kmalloc(len, GFP_KERNEL);
	if (code == NULL)
		return -ENOMEM;

	if (copy_from_user(code, uprog.filter, len)) {
		kfree(code);
		return -EFAULT;
	}

	err = sk_chk_filter(code, uprog.len);
	if (err) {
		kfree(code);
		return err;
	}

	*p = code;
	return uprog.len;
}
#endif /* CONFIG_PPP_FILTER */

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static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
	struct ppp_file *pf = file->private_data;
	struct ppp *ppp;
	int err = -EFAULT, val, val2, i;
	struct ppp_idle idle;
	struct npioctl npi;
	int unit, cflags;
	struct slcompress *vj;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;

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	if (!pf)
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		return ppp_unattached_ioctl(current->nsproxy->net_ns,
					pf, file, cmd, arg);
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	if (cmd == PPPIOCDETACH) {
		/*
		 * We have to be careful here... if the file descriptor
		 * has been dup'd, we could have another process in the
		 * middle of a poll using the same file *, so we had
		 * better not free the interface data structures -
		 * instead we fail the ioctl.  Even in this case, we
		 * shut down the interface if we are the owner of it.
		 * Actually, we should get rid of PPPIOCDETACH, userland
		 * (i.e. pppd) could achieve the same effect by closing
		 * this fd and reopening /dev/ppp.
		 */
		err = -EINVAL;
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		lock_kernel();
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		if (pf->kind == INTERFACE) {
			ppp = PF_TO_PPP(pf);
			if (file == ppp->owner)
				ppp_shutdown_interface(ppp);
		}
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Al Viro 已提交
593
		if (atomic_long_read(&file->f_count) <= 2) {
A
Alan Cox 已提交
594
			ppp_release(NULL, file);
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Linus Torvalds 已提交
595 596
			err = 0;
		} else
A
Al Viro 已提交
597 598
			printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
			       atomic_long_read(&file->f_count));
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Alan Cox 已提交
599
		unlock_kernel();
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		return err;
	}

	if (pf->kind == CHANNEL) {
A
Alan Cox 已提交
604
		struct channel *pch;
L
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		struct ppp_channel *chan;

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		lock_kernel();
		pch = PF_TO_CHANNEL(pf);

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		switch (cmd) {
		case PPPIOCCONNECT:
			if (get_user(unit, p))
				break;
			err = ppp_connect_channel(pch, unit);
			break;

		case PPPIOCDISCONN:
			err = ppp_disconnect_channel(pch);
			break;

		default:
			down_read(&pch->chan_sem);
			chan = pch->chan;
			err = -ENOTTY;
			if (chan && chan->ops->ioctl)
				err = chan->ops->ioctl(chan, cmd, arg);
			up_read(&pch->chan_sem);
		}
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		unlock_kernel();
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		return err;
	}

	if (pf->kind != INTERFACE) {
		/* can't happen */
		printk(KERN_ERR "PPP: not interface or channel??\n");
		return -EINVAL;
	}

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	lock_kernel();
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	ppp = PF_TO_PPP(pf);
	switch (cmd) {
	case PPPIOCSMRU:
		if (get_user(val, p))
			break;
		ppp->mru = val;
		err = 0;
		break;

	case PPPIOCSFLAGS:
		if (get_user(val, p))
			break;
		ppp_lock(ppp);
		cflags = ppp->flags & ~val;
		ppp->flags = val & SC_FLAG_BITS;
		ppp_unlock(ppp);
		if (cflags & SC_CCP_OPEN)
			ppp_ccp_closed(ppp);
		err = 0;
		break;

	case PPPIOCGFLAGS:
		val = ppp->flags | ppp->xstate | ppp->rstate;
		if (put_user(val, p))
			break;
		err = 0;
		break;

	case PPPIOCSCOMPRESS:
		err = ppp_set_compress(ppp, arg);
		break;

	case PPPIOCGUNIT:
		if (put_user(ppp->file.index, p))
			break;
		err = 0;
		break;

	case PPPIOCSDEBUG:
		if (get_user(val, p))
			break;
		ppp->debug = val;
		err = 0;
		break;

	case PPPIOCGDEBUG:
		if (put_user(ppp->debug, p))
			break;
		err = 0;
		break;

	case PPPIOCGIDLE:
		idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
		idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
		if (copy_to_user(argp, &idle, sizeof(idle)))
			break;
		err = 0;
		break;

	case PPPIOCSMAXCID:
		if (get_user(val, p))
			break;
		val2 = 15;
		if ((val >> 16) != 0) {
			val2 = val >> 16;
			val &= 0xffff;
		}
		vj = slhc_init(val2+1, val+1);
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Joe Perches 已提交
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		if (!vj) {
L
Linus Torvalds 已提交
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			printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
			err = -ENOMEM;
			break;
		}
		ppp_lock(ppp);
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Joe Perches 已提交
714
		if (ppp->vj)
L
Linus Torvalds 已提交
715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786
			slhc_free(ppp->vj);
		ppp->vj = vj;
		ppp_unlock(ppp);
		err = 0;
		break;

	case PPPIOCGNPMODE:
	case PPPIOCSNPMODE:
		if (copy_from_user(&npi, argp, sizeof(npi)))
			break;
		err = proto_to_npindex(npi.protocol);
		if (err < 0)
			break;
		i = err;
		if (cmd == PPPIOCGNPMODE) {
			err = -EFAULT;
			npi.mode = ppp->npmode[i];
			if (copy_to_user(argp, &npi, sizeof(npi)))
				break;
		} else {
			ppp->npmode[i] = npi.mode;
			/* we may be able to transmit more packets now (??) */
			netif_wake_queue(ppp->dev);
		}
		err = 0;
		break;

#ifdef CONFIG_PPP_FILTER
	case PPPIOCSPASS:
	{
		struct sock_filter *code;
		err = get_filter(argp, &code);
		if (err >= 0) {
			ppp_lock(ppp);
			kfree(ppp->pass_filter);
			ppp->pass_filter = code;
			ppp->pass_len = err;
			ppp_unlock(ppp);
			err = 0;
		}
		break;
	}
	case PPPIOCSACTIVE:
	{
		struct sock_filter *code;
		err = get_filter(argp, &code);
		if (err >= 0) {
			ppp_lock(ppp);
			kfree(ppp->active_filter);
			ppp->active_filter = code;
			ppp->active_len = err;
			ppp_unlock(ppp);
			err = 0;
		}
		break;
	}
#endif /* CONFIG_PPP_FILTER */

#ifdef CONFIG_PPP_MULTILINK
	case PPPIOCSMRRU:
		if (get_user(val, p))
			break;
		ppp_recv_lock(ppp);
		ppp->mrru = val;
		ppp_recv_unlock(ppp);
		err = 0;
		break;
#endif /* CONFIG_PPP_MULTILINK */

	default:
		err = -ENOTTY;
	}
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	unlock_kernel();
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	return err;
}

791 792
static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
			struct file *file, unsigned int cmd, unsigned long arg)
L
Linus Torvalds 已提交
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{
	int unit, err = -EFAULT;
	struct ppp *ppp;
	struct channel *chan;
797
	struct ppp_net *pn;
L
Linus Torvalds 已提交
798 799
	int __user *p = (int __user *)arg;

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800
	lock_kernel();
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801 802 803 804 805
	switch (cmd) {
	case PPPIOCNEWUNIT:
		/* Create a new ppp unit */
		if (get_user(unit, p))
			break;
806
		ppp = ppp_create_interface(net, unit, &err);
J
Joe Perches 已提交
807
		if (!ppp)
L
Linus Torvalds 已提交
808 809 810 811 812 813 814 815 816 817 818 819 820 821
			break;
		file->private_data = &ppp->file;
		ppp->owner = file;
		err = -EFAULT;
		if (put_user(ppp->file.index, p))
			break;
		err = 0;
		break;

	case PPPIOCATTACH:
		/* Attach to an existing ppp unit */
		if (get_user(unit, p))
			break;
		err = -ENXIO;
822 823 824
		pn = ppp_pernet(net);
		mutex_lock(&pn->all_ppp_mutex);
		ppp = ppp_find_unit(pn, unit);
J
Joe Perches 已提交
825
		if (ppp) {
L
Linus Torvalds 已提交
826 827 828 829
			atomic_inc(&ppp->file.refcnt);
			file->private_data = &ppp->file;
			err = 0;
		}
830
		mutex_unlock(&pn->all_ppp_mutex);
L
Linus Torvalds 已提交
831 832 833 834 835 836
		break;

	case PPPIOCATTCHAN:
		if (get_user(unit, p))
			break;
		err = -ENXIO;
837 838 839
		pn = ppp_pernet(net);
		spin_lock_bh(&pn->all_channels_lock);
		chan = ppp_find_channel(pn, unit);
J
Joe Perches 已提交
840
		if (chan) {
L
Linus Torvalds 已提交
841 842 843 844
			atomic_inc(&chan->file.refcnt);
			file->private_data = &chan->file;
			err = 0;
		}
845
		spin_unlock_bh(&pn->all_channels_lock);
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846 847 848 849 850
		break;

	default:
		err = -ENOTTY;
	}
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851
	unlock_kernel();
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852 853 854
	return err;
}

855
static const struct file_operations ppp_device_fops = {
L
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	.owner		= THIS_MODULE,
	.read		= ppp_read,
	.write		= ppp_write,
	.poll		= ppp_poll,
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Alan Cox 已提交
860
	.unlocked_ioctl	= ppp_ioctl,
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	.open		= ppp_open,
	.release	= ppp_release
};

865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904
static __net_init int ppp_init_net(struct net *net)
{
	struct ppp_net *pn;
	int err;

	pn = kzalloc(sizeof(*pn), GFP_KERNEL);
	if (!pn)
		return -ENOMEM;

	idr_init(&pn->units_idr);
	mutex_init(&pn->all_ppp_mutex);

	INIT_LIST_HEAD(&pn->all_channels);
	INIT_LIST_HEAD(&pn->new_channels);

	spin_lock_init(&pn->all_channels_lock);

	err = net_assign_generic(net, ppp_net_id, pn);
	if (err) {
		kfree(pn);
		return err;
	}

	return 0;
}

static __net_exit void ppp_exit_net(struct net *net)
{
	struct ppp_net *pn;

	pn = net_generic(net, ppp_net_id);
	idr_destroy(&pn->units_idr);
	/*
	 * if someone has cached our net then
	 * further net_generic call will return NULL
	 */
	net_assign_generic(net, ppp_net_id, NULL);
	kfree(pn);
}

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Alexey Dobriyan 已提交
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static struct pernet_operations ppp_net_ops = {
906 907 908 909
	.init = ppp_init_net,
	.exit = ppp_exit_net,
};

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#define PPP_MAJOR	108

/* Called at boot time if ppp is compiled into the kernel,
   or at module load time (from init_module) if compiled as a module. */
static int __init ppp_init(void)
{
	int err;

	printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
919 920 921 922 923

	err = register_pernet_gen_device(&ppp_net_id, &ppp_net_ops);
	if (err) {
		printk(KERN_ERR "failed to register PPP pernet device (%d)\n", err);
		goto out;
L
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	}

926 927
	err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
	if (err) {
L
Linus Torvalds 已提交
928
		printk(KERN_ERR "failed to register PPP device (%d)\n", err);
929 930 931 932 933 934 935 936 937 938 939 940 941
		goto out_net;
	}

	ppp_class = class_create(THIS_MODULE, "ppp");
	if (IS_ERR(ppp_class)) {
		err = PTR_ERR(ppp_class);
		goto out_chrdev;
	}

	/* not a big deal if we fail here :-) */
	device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");

	return 0;
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out_chrdev:
	unregister_chrdev(PPP_MAJOR, "ppp");
945 946 947 948
out_net:
	unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
out:
	return err;
L
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949 950 951 952 953
}

/*
 * Network interface unit routines.
 */
954
static netdev_tx_t
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955 956
ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
957
	struct ppp *ppp = netdev_priv(dev);
L
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958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979
	int npi, proto;
	unsigned char *pp;

	npi = ethertype_to_npindex(ntohs(skb->protocol));
	if (npi < 0)
		goto outf;

	/* Drop, accept or reject the packet */
	switch (ppp->npmode[npi]) {
	case NPMODE_PASS:
		break;
	case NPMODE_QUEUE:
		/* it would be nice to have a way to tell the network
		   system to queue this one up for later. */
		goto outf;
	case NPMODE_DROP:
	case NPMODE_ERROR:
		goto outf;
	}

	/* Put the 2-byte PPP protocol number on the front,
	   making sure there is room for the address and control fields. */
980 981 982
	if (skb_cow_head(skb, PPP_HDRLEN))
		goto outf;

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Linus Torvalds 已提交
983 984 985 986 987 988 989 990
	pp = skb_push(skb, 2);
	proto = npindex_to_proto[npi];
	pp[0] = proto >> 8;
	pp[1] = proto;

	netif_stop_queue(dev);
	skb_queue_tail(&ppp->file.xq, skb);
	ppp_xmit_process(ppp);
991
	return NETDEV_TX_OK;
L
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 outf:
	kfree_skb(skb);
995
	++dev->stats.tx_dropped;
996
	return NETDEV_TX_OK;
L
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}

static int
ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
1002
	struct ppp *ppp = netdev_priv(dev);
L
Linus Torvalds 已提交
1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018
	int err = -EFAULT;
	void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
	struct ppp_stats stats;
	struct ppp_comp_stats cstats;
	char *vers;

	switch (cmd) {
	case SIOCGPPPSTATS:
		ppp_get_stats(ppp, &stats);
		if (copy_to_user(addr, &stats, sizeof(stats)))
			break;
		err = 0;
		break;

	case SIOCGPPPCSTATS:
		memset(&cstats, 0, sizeof(cstats));
J
Joe Perches 已提交
1019
		if (ppp->xc_state)
L
Linus Torvalds 已提交
1020
			ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
J
Joe Perches 已提交
1021
		if (ppp->rc_state)
L
Linus Torvalds 已提交
1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041
			ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
		if (copy_to_user(addr, &cstats, sizeof(cstats)))
			break;
		err = 0;
		break;

	case SIOCGPPPVER:
		vers = PPP_VERSION;
		if (copy_to_user(addr, vers, strlen(vers) + 1))
			break;
		err = 0;
		break;

	default:
		err = -EINVAL;
	}

	return err;
}

S
Stephen Hemminger 已提交
1042
static const struct net_device_ops ppp_netdev_ops = {
1043 1044
	.ndo_start_xmit = ppp_start_xmit,
	.ndo_do_ioctl   = ppp_net_ioctl,
S
Stephen Hemminger 已提交
1045 1046
};

L
Linus Torvalds 已提交
1047 1048
static void ppp_setup(struct net_device *dev)
{
S
Stephen Hemminger 已提交
1049
	dev->netdev_ops = &ppp_netdev_ops;
L
Linus Torvalds 已提交
1050 1051 1052 1053 1054 1055
	dev->hard_header_len = PPP_HDRLEN;
	dev->mtu = PPP_MTU;
	dev->addr_len = 0;
	dev->tx_queue_len = 3;
	dev->type = ARPHRD_PPP;
	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1056
	dev->features |= NETIF_F_NETNS_LOCAL;
1057
	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
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}

/*
 * Transmit-side routines.
 */

/*
 * Called to do any work queued up on the transmit side
 * that can now be done.
 */
static void
ppp_xmit_process(struct ppp *ppp)
{
	struct sk_buff *skb;

	ppp_xmit_lock(ppp);
1074
	if (!ppp->closing) {
L
Linus Torvalds 已提交
1075
		ppp_push(ppp);
J
Joe Perches 已提交
1076 1077
		while (!ppp->xmit_pending
		       && (skb = skb_dequeue(&ppp->file.xq)))
L
Linus Torvalds 已提交
1078 1079 1080
			ppp_send_frame(ppp, skb);
		/* If there's no work left to do, tell the core net
		   code that we can accept some more. */
J
Joe Perches 已提交
1081
		if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
L
Linus Torvalds 已提交
1082 1083 1084 1085 1086
			netif_wake_queue(ppp->dev);
	}
	ppp_xmit_unlock(ppp);
}

1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136
static inline struct sk_buff *
pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
{
	struct sk_buff *new_skb;
	int len;
	int new_skb_size = ppp->dev->mtu +
		ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
	int compressor_skb_size = ppp->dev->mtu +
		ppp->xcomp->comp_extra + PPP_HDRLEN;
	new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
	if (!new_skb) {
		if (net_ratelimit())
			printk(KERN_ERR "PPP: no memory (comp pkt)\n");
		return NULL;
	}
	if (ppp->dev->hard_header_len > PPP_HDRLEN)
		skb_reserve(new_skb,
			    ppp->dev->hard_header_len - PPP_HDRLEN);

	/* compressor still expects A/C bytes in hdr */
	len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
				   new_skb->data, skb->len + 2,
				   compressor_skb_size);
	if (len > 0 && (ppp->flags & SC_CCP_UP)) {
		kfree_skb(skb);
		skb = new_skb;
		skb_put(skb, len);
		skb_pull(skb, 2);	/* pull off A/C bytes */
	} else if (len == 0) {
		/* didn't compress, or CCP not up yet */
		kfree_skb(new_skb);
		new_skb = skb;
	} else {
		/*
		 * (len < 0)
		 * MPPE requires that we do not send unencrypted
		 * frames.  The compressor will return -1 if we
		 * should drop the frame.  We cannot simply test
		 * the compress_proto because MPPE and MPPC share
		 * the same number.
		 */
		if (net_ratelimit())
			printk(KERN_ERR "ppp: compressor dropped pkt\n");
		kfree_skb(skb);
		kfree_skb(new_skb);
		new_skb = NULL;
	}
	return new_skb;
}

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Linus Torvalds 已提交
1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175
/*
 * Compress and send a frame.
 * The caller should have locked the xmit path,
 * and xmit_pending should be 0.
 */
static void
ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
{
	int proto = PPP_PROTO(skb);
	struct sk_buff *new_skb;
	int len;
	unsigned char *cp;

	if (proto < 0x8000) {
#ifdef CONFIG_PPP_FILTER
		/* check if we should pass this packet */
		/* the filter instructions are constructed assuming
		   a four-byte PPP header on each packet */
		*skb_push(skb, 2) = 1;
		if (ppp->pass_filter
		    && sk_run_filter(skb, ppp->pass_filter,
				     ppp->pass_len) == 0) {
			if (ppp->debug & 1)
				printk(KERN_DEBUG "PPP: outbound frame not passed\n");
			kfree_skb(skb);
			return;
		}
		/* if this packet passes the active filter, record the time */
		if (!(ppp->active_filter
		      && sk_run_filter(skb, ppp->active_filter,
				       ppp->active_len) == 0))
			ppp->last_xmit = jiffies;
		skb_pull(skb, 2);
#else
		/* for data packets, record the time */
		ppp->last_xmit = jiffies;
#endif /* CONFIG_PPP_FILTER */
	}

1176 1177
	++ppp->dev->stats.tx_packets;
	ppp->dev->stats.tx_bytes += skb->len - 2;
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	switch (proto) {
	case PPP_IP:
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Joe Perches 已提交
1181
		if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
L
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1182 1183 1184 1185
			break;
		/* try to do VJ TCP header compression */
		new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
				    GFP_ATOMIC);
J
Joe Perches 已提交
1186
		if (!new_skb) {
L
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1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220
			printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
			goto drop;
		}
		skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
		cp = skb->data + 2;
		len = slhc_compress(ppp->vj, cp, skb->len - 2,
				    new_skb->data + 2, &cp,
				    !(ppp->flags & SC_NO_TCP_CCID));
		if (cp == skb->data + 2) {
			/* didn't compress */
			kfree_skb(new_skb);
		} else {
			if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
				proto = PPP_VJC_COMP;
				cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
			} else {
				proto = PPP_VJC_UNCOMP;
				cp[0] = skb->data[2];
			}
			kfree_skb(skb);
			skb = new_skb;
			cp = skb_put(skb, len + 2);
			cp[0] = 0;
			cp[1] = proto;
		}
		break;

	case PPP_CCP:
		/* peek at outbound CCP frames */
		ppp_ccp_peek(ppp, skb, 0);
		break;
	}

	/* try to do packet compression */
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	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
L
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	    && proto != PPP_LCP && proto != PPP_CCP) {
1223 1224 1225
		if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
			if (net_ratelimit())
				printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
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1226 1227
			goto drop;
		}
1228 1229 1230
		skb = pad_compress_skb(ppp, skb);
		if (!skb)
			goto drop;
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	}

	/*
	 * If we are waiting for traffic (demand dialling),
	 * queue it up for pppd to receive.
	 */
	if (ppp->flags & SC_LOOP_TRAFFIC) {
		if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
			goto drop;
		skb_queue_tail(&ppp->file.rq, skb);
		wake_up_interruptible(&ppp->file.rwait);
		return;
	}

	ppp->xmit_pending = skb;
	ppp_push(ppp);
	return;

 drop:
1250
	kfree_skb(skb);
1251
	++ppp->dev->stats.tx_errors;
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}

/*
 * Try to send the frame in xmit_pending.
 * The caller should have the xmit path locked.
 */
static void
ppp_push(struct ppp *ppp)
{
	struct list_head *list;
	struct channel *pch;
	struct sk_buff *skb = ppp->xmit_pending;

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	if (!skb)
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		return;

	list = &ppp->channels;
	if (list_empty(list)) {
		/* nowhere to send the packet, just drop it */
		ppp->xmit_pending = NULL;
		kfree_skb(skb);
		return;
	}

	if ((ppp->flags & SC_MULTILINK) == 0) {
		/* not doing multilink: send it down the first channel */
		list = list->next;
		pch = list_entry(list, struct channel, clist);

		spin_lock_bh(&pch->downl);
		if (pch->chan) {
			if (pch->chan->ops->start_xmit(pch->chan, skb))
				ppp->xmit_pending = NULL;
		} else {
			/* channel got unregistered */
			kfree_skb(skb);
			ppp->xmit_pending = NULL;
		}
		spin_unlock_bh(&pch->downl);
		return;
	}

#ifdef CONFIG_PPP_MULTILINK
	/* Multilink: fragment the packet over as many links
	   as can take the packet at the moment. */
	if (!ppp_mp_explode(ppp, skb))
		return;
#endif /* CONFIG_PPP_MULTILINK */

	ppp->xmit_pending = NULL;
	kfree_skb(skb);
}

#ifdef CONFIG_PPP_MULTILINK
/*
 * Divide a packet to be transmitted into fragments and
 * send them out the individual links.
 */
static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
{
1312 1313 1314 1315 1316 1317 1318
	int	len, totlen;
	int	i, bits, hdrlen, mtu;
	int	flen;
	int	navail,	nfree, nzero;
	int	nbigger;
	int	totspeed;
	int	totfree;
L
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1319 1320 1321 1322 1323 1324
	unsigned char *p, *q;
	struct list_head *list;
	struct channel *pch;
	struct sk_buff *frag;
	struct ppp_channel *chan;

1325 1326
	totspeed = 0; /*total bitrate of the bundle*/
	nfree =	0;	/* # channels which	have no	packet already queued */
1327
	navail = 0;	/* total # of usable channels (not deregistered) */
1328 1329 1330 1331 1332
	nzero =	0; /* number of	channels with zero speed associated*/
	totfree	= 0; /*total # of channels available and
				  *having no queued packets before
				  *starting the fragmentation*/

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	hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1334 1335
	i =	0;
	list_for_each_entry(pch, &ppp->channels, clist)	{
1336
		navail += pch->avail = (pch->chan != NULL);
1337 1338
		pch->speed = pch->chan->speed;
		if (pch->avail)	{
1339
			if (skb_queue_empty(&pch->file.xq) ||
1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351
				!pch->had_frag)	{
					if (pch->speed == 0)
						nzero++;
					else
						totspeed += pch->speed;

					pch->avail = 2;
					++nfree;
					++totfree;
				}
			if (!pch->had_frag && i	< ppp->nxchan)
				ppp->nxchan	= i;
L
Linus Torvalds 已提交
1352
		}
1353
		++i;
L
Linus Torvalds 已提交
1354
	}
1355
	/*
1356 1357 1358
	 * Don't start sending this	packet unless at least half	of
	 * the channels	are	free.  This	gives much better TCP
	 * performance if we have a	lot	of channels.
1359
	 */
1360 1361
	if (nfree == 0 || nfree	< navail / 2)
		return 0; /* can't take now, leave it in xmit_pending	*/
L
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1362 1363

	/* Do protocol field compression (XXX this should be optional) */
1364 1365
	p =	skb->data;
	len	= skb->len;
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	if (*p == 0) {
		++p;
		--len;
	}

1371 1372 1373 1374 1375
	totlen = len;
	nbigger	= len %	nfree;

	/* skip	to the channel after the one we	last used
	   and start at	that one */
1376
	list = &ppp->channels;
1377
	for	(i = 0;	i <	ppp->nxchan; ++i) {
L
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1378
		list = list->next;
1379 1380
		if (list ==	&ppp->channels)	{
			i =	0;
L
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1381 1382 1383 1384
			break;
		}
	}

1385
	/* create a	fragment for each channel */
L
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1386
	bits = B;
1387
	while (len	> 0) {
L
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1388
		list = list->next;
1389 1390
		if (list ==	&ppp->channels)	{
			i =	0;
L
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1391 1392
			continue;
		}
1393
		pch	= list_entry(list, struct channel, clist);
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		++i;
		if (!pch->avail)
			continue;

1398
		/*
1399 1400
		 * Skip	this channel if	it has a fragment pending already and
		 * we haven't given	a fragment to all of the free channels.
1401 1402
		 */
		if (pch->avail == 1) {
1403
			if (nfree >	0)
1404 1405 1406 1407 1408
				continue;
		} else {
			pch->avail = 1;
		}

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		/* check the channel's mtu and whether it is still attached. */
		spin_lock_bh(&pch->downl);
1411
		if (pch->chan == NULL) {
1412 1413 1414 1415 1416 1417
			/* can't use this channel, it's	being deregistered */
			if (pch->speed == 0)
				nzero--;
			else
				totspeed -=	pch->speed;

L
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			spin_unlock_bh(&pch->downl);
			pch->avail = 0;
1420 1421 1422 1423
			totlen = len;
			totfree--;
			nfree--;
			if (--navail ==	0)
L
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				break;
			continue;
		}

		/*
1429 1430 1431 1432 1433
		*if the channel speed is not set divide
		*the packet	evenly among the free channels;
		*otherwise divide it according to the speed
		*of the channel we are going to transmit on
		*/
1434
		flen = len;
1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447
		if (nfree > 0) {
			if (pch->speed == 0) {
				flen = totlen/nfree	;
				if (nbigger > 0) {
					flen++;
					nbigger--;
				}
			} else {
				flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
					((totspeed*totfree)/pch->speed)) - hdrlen;
				if (nbigger > 0) {
					flen += ((totfree - nzero)*pch->speed)/totspeed;
					nbigger -= ((totfree - nzero)*pch->speed)/
1448
							totspeed;
1449
				}
1450
			}
1451
			nfree--;
1452 1453 1454 1455 1456 1457 1458
		}

		/*
		 *check	if we are on the last channel or
		 *we exceded the lenght	of the data	to
		 *fragment
		 */
1459
		if ((nfree <= 0) || (flen > len))
1460 1461 1462 1463 1464 1465
			flen = len;
		/*
		 *it is not worth to tx on slow channels:
		 *in that case from the resulting flen according to the
		 *above formula will be equal or less than zero.
		 *Skip the channel in this case
L
Linus Torvalds 已提交
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		 */
1467 1468 1469 1470 1471 1472
		if (flen <=	0) {
			pch->avail = 2;
			spin_unlock_bh(&pch->downl);
			continue;
		}

1473
		mtu	= pch->chan->mtu - hdrlen;
1474 1475
		if (mtu	< 4)
			mtu	= 4;
1476 1477
		if (flen > mtu)
			flen = mtu;
1478 1479 1480
		if (flen ==	len)
			bits |=	E;
		frag = alloc_skb(flen +	hdrlen + (flen == 0), GFP_ATOMIC);
J
Joe Perches 已提交
1481
		if (!frag)
1482
			goto noskb;
1483
		q =	skb_put(frag, flen + hdrlen);
1484

1485
		/* make	the	MP header */
1486 1487 1488
		q[0] = PPP_MP >> 8;
		q[1] = PPP_MP;
		if (ppp->flags & SC_MP_XSHORTSEQ) {
1489
			q[2] = bits	+ ((ppp->nxseq >> 8) & 0xf);
1490 1491 1492 1493 1494 1495
			q[3] = ppp->nxseq;
		} else {
			q[2] = bits;
			q[3] = ppp->nxseq >> 16;
			q[4] = ppp->nxseq >> 8;
			q[5] = ppp->nxseq;
L
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1496
		}
1497

1498
		memcpy(q + hdrlen, p, flen);
1499 1500 1501

		/* try to send it down the channel */
		chan = pch->chan;
1502 1503
		if (!skb_queue_empty(&pch->file.xq)	||
			!chan->ops->start_xmit(chan, frag))
1504
			skb_queue_tail(&pch->file.xq, frag);
1505
		pch->had_frag =	1;
1506
		p += flen;
1507
		len	-= flen;
1508 1509
		++ppp->nxseq;
		bits = 0;
L
Linus Torvalds 已提交
1510
		spin_unlock_bh(&pch->downl);
1511
	}
1512
	ppp->nxchan	= i;
L
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1513 1514 1515 1516 1517 1518

	return 1;

 noskb:
	spin_unlock_bh(&pch->downl);
	if (ppp->debug & 1)
1519
		printk(KERN_ERR	"PPP: no memory	(fragment)\n");
1520
	++ppp->dev->stats.tx_errors;
L
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1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535
	++ppp->nxseq;
	return 1;	/* abandon the frame */
}
#endif /* CONFIG_PPP_MULTILINK */

/*
 * Try to send data out on a channel.
 */
static void
ppp_channel_push(struct channel *pch)
{
	struct sk_buff *skb;
	struct ppp *ppp;

	spin_lock_bh(&pch->downl);
J
Joe Perches 已提交
1536
	if (pch->chan) {
1537
		while (!skb_queue_empty(&pch->file.xq)) {
L
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1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550
			skb = skb_dequeue(&pch->file.xq);
			if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
				/* put the packet back and try again later */
				skb_queue_head(&pch->file.xq, skb);
				break;
			}
		}
	} else {
		/* channel got deregistered */
		skb_queue_purge(&pch->file.xq);
	}
	spin_unlock_bh(&pch->downl);
	/* see if there is anything from the attached unit to be sent */
1551
	if (skb_queue_empty(&pch->file.xq)) {
L
Linus Torvalds 已提交
1552 1553
		read_lock_bh(&pch->upl);
		ppp = pch->ppp;
J
Joe Perches 已提交
1554
		if (ppp)
L
Linus Torvalds 已提交
1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571
			ppp_xmit_process(ppp);
		read_unlock_bh(&pch->upl);
	}
}

/*
 * Receive-side routines.
 */

/* misuse a few fields of the skb for MP reconstruction */
#define sequence	priority
#define BEbits		cb[0]

static inline void
ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
{
	ppp_recv_lock(ppp);
1572
	if (!ppp->closing)
L
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1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584
		ppp_receive_frame(ppp, skb, pch);
	else
		kfree_skb(skb);
	ppp_recv_unlock(ppp);
}

void
ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
{
	struct channel *pch = chan->ppp;
	int proto;

J
Joe Perches 已提交
1585
	if (!pch || skb->len == 0) {
L
Linus Torvalds 已提交
1586 1587 1588
		kfree_skb(skb);
		return;
	}
1589

L
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1590 1591
	proto = PPP_PROTO(skb);
	read_lock_bh(&pch->upl);
J
Joe Perches 已提交
1592
	if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
L
Linus Torvalds 已提交
1593 1594 1595 1596
		/* put it on the channel queue */
		skb_queue_tail(&pch->file.rq, skb);
		/* drop old frames if queue too long */
		while (pch->file.rq.qlen > PPP_MAX_RQLEN
J
Joe Perches 已提交
1597
		       && (skb = skb_dequeue(&pch->file.rq)))
L
Linus Torvalds 已提交
1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612
			kfree_skb(skb);
		wake_up_interruptible(&pch->file.rwait);
	} else {
		ppp_do_recv(pch->ppp, skb, pch);
	}
	read_unlock_bh(&pch->upl);
}

/* Put a 0-length skb in the receive queue as an error indication */
void
ppp_input_error(struct ppp_channel *chan, int code)
{
	struct channel *pch = chan->ppp;
	struct sk_buff *skb;

J
Joe Perches 已提交
1613
	if (!pch)
L
Linus Torvalds 已提交
1614 1615 1616
		return;

	read_lock_bh(&pch->upl);
J
Joe Perches 已提交
1617
	if (pch->ppp) {
L
Linus Torvalds 已提交
1618
		skb = alloc_skb(0, GFP_ATOMIC);
J
Joe Perches 已提交
1619
		if (skb) {
L
Linus Torvalds 已提交
1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634
			skb->len = 0;		/* probably unnecessary */
			skb->cb[0] = code;
			ppp_do_recv(pch->ppp, skb, pch);
		}
	}
	read_unlock_bh(&pch->upl);
}

/*
 * We come in here to process a received frame.
 * The receive side of the ppp unit is locked.
 */
static void
ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
{
1635
	if (pskb_may_pull(skb, 2)) {
L
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1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647
#ifdef CONFIG_PPP_MULTILINK
		/* XXX do channel-level decompression here */
		if (PPP_PROTO(skb) == PPP_MP)
			ppp_receive_mp_frame(ppp, skb, pch);
		else
#endif /* CONFIG_PPP_MULTILINK */
			ppp_receive_nonmp_frame(ppp, skb);
		return;
	}

	if (skb->len > 0)
		/* note: a 0-length skb is used as an error indication */
1648
		++ppp->dev->stats.rx_length_errors;
L
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1649 1650 1651 1652 1653 1654 1655 1656

	kfree_skb(skb);
	ppp_receive_error(ppp);
}

static void
ppp_receive_error(struct ppp *ppp)
{
1657
	++ppp->dev->stats.rx_errors;
J
Joe Perches 已提交
1658
	if (ppp->vj)
L
Linus Torvalds 已提交
1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672
		slhc_toss(ppp->vj);
}

static void
ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
{
	struct sk_buff *ns;
	int proto, len, npi;

	/*
	 * Decompress the frame, if compressed.
	 * Note that some decompressors need to see uncompressed frames
	 * that come in as well as compressed frames.
	 */
J
Joe Perches 已提交
1673
	if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
L
Linus Torvalds 已提交
1674 1675 1676
	    && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
		skb = ppp_decompress_frame(ppp, skb);

1677 1678 1679
	if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
		goto err;

L
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1680 1681 1682 1683
	proto = PPP_PROTO(skb);
	switch (proto) {
	case PPP_VJC_COMP:
		/* decompress VJ compressed packets */
J
Joe Perches 已提交
1684
		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
L
Linus Torvalds 已提交
1685 1686
			goto err;

1687
		if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
L
Linus Torvalds 已提交
1688 1689
			/* copy to a new sk_buff with more tailroom */
			ns = dev_alloc_skb(skb->len + 128);
J
Joe Perches 已提交
1690
			if (!ns) {
L
Linus Torvalds 已提交
1691 1692 1693 1694 1695 1696 1697 1698
				printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
				goto err;
			}
			skb_reserve(ns, 2);
			skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
			kfree_skb(skb);
			skb = ns;
		}
1699 1700
		else
			skb->ip_summed = CHECKSUM_NONE;
L
Linus Torvalds 已提交
1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715

		len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
		if (len <= 0) {
			printk(KERN_DEBUG "PPP: VJ decompression error\n");
			goto err;
		}
		len += 2;
		if (len > skb->len)
			skb_put(skb, len - skb->len);
		else if (len < skb->len)
			skb_trim(skb, len);
		proto = PPP_IP;
		break;

	case PPP_VJC_UNCOMP:
J
Joe Perches 已提交
1716
		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
L
Linus Torvalds 已提交
1717
			goto err;
1718

L
Linus Torvalds 已提交
1719 1720 1721
		/* Until we fix the decompressor need to make sure
		 * data portion is linear.
		 */
1722
		if (!pskb_may_pull(skb, skb->len))
L
Linus Torvalds 已提交
1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736
			goto err;

		if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
			printk(KERN_ERR "PPP: VJ uncompressed error\n");
			goto err;
		}
		proto = PPP_IP;
		break;

	case PPP_CCP:
		ppp_ccp_peek(ppp, skb, 1);
		break;
	}

1737 1738
	++ppp->dev->stats.rx_packets;
	ppp->dev->stats.rx_bytes += skb->len - 2;
L
Linus Torvalds 已提交
1739 1740 1741 1742 1743 1744 1745

	npi = proto_to_npindex(proto);
	if (npi < 0) {
		/* control or unknown frame - pass it to pppd */
		skb_queue_tail(&ppp->file.rq, skb);
		/* limit queue length by dropping old frames */
		while (ppp->file.rq.qlen > PPP_MAX_RQLEN
J
Joe Perches 已提交
1746
		       && (skb = skb_dequeue(&ppp->file.rq)))
L
Linus Torvalds 已提交
1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757
			kfree_skb(skb);
		/* wake up any process polling or blocking on read */
		wake_up_interruptible(&ppp->file.rwait);

	} else {
		/* network protocol frame - give it to the kernel */

#ifdef CONFIG_PPP_FILTER
		/* check if the packet passes the pass and active filters */
		/* the filter instructions are constructed assuming
		   a four-byte PPP header on each packet */
1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778
		if (ppp->pass_filter || ppp->active_filter) {
			if (skb_cloned(skb) &&
			    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
				goto err;

			*skb_push(skb, 2) = 0;
			if (ppp->pass_filter
			    && sk_run_filter(skb, ppp->pass_filter,
					     ppp->pass_len) == 0) {
				if (ppp->debug & 1)
					printk(KERN_DEBUG "PPP: inbound frame "
					       "not passed\n");
				kfree_skb(skb);
				return;
			}
			if (!(ppp->active_filter
			      && sk_run_filter(skb, ppp->active_filter,
					       ppp->active_len) == 0))
				ppp->last_recv = jiffies;
			__skb_pull(skb, 2);
		} else
L
Linus Torvalds 已提交
1779
#endif /* CONFIG_PPP_FILTER */
1780
			ppp->last_recv = jiffies;
L
Linus Torvalds 已提交
1781 1782 1783 1784 1785

		if ((ppp->dev->flags & IFF_UP) == 0
		    || ppp->npmode[npi] != NPMODE_PASS) {
			kfree_skb(skb);
		} else {
1786 1787
			/* chop off protocol */
			skb_pull_rcsum(skb, 2);
L
Linus Torvalds 已提交
1788 1789
			skb->dev = ppp->dev;
			skb->protocol = htons(npindex_to_ethertype[npi]);
1790
			skb_reset_mac_header(skb);
L
Linus Torvalds 已提交
1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814
			netif_rx(skb);
		}
	}
	return;

 err:
	kfree_skb(skb);
	ppp_receive_error(ppp);
}

static struct sk_buff *
ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
{
	int proto = PPP_PROTO(skb);
	struct sk_buff *ns;
	int len;

	/* Until we fix all the decompressor's need to make sure
	 * data portion is linear.
	 */
	if (!pskb_may_pull(skb, skb->len))
		goto err;

	if (proto == PPP_COMP) {
1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826
		int obuff_size;

		switch(ppp->rcomp->compress_proto) {
		case CI_MPPE:
			obuff_size = ppp->mru + PPP_HDRLEN + 1;
			break;
		default:
			obuff_size = ppp->mru + PPP_HDRLEN;
			break;
		}

		ns = dev_alloc_skb(obuff_size);
J
Joe Perches 已提交
1827
		if (!ns) {
L
Linus Torvalds 已提交
1828 1829 1830 1831 1832
			printk(KERN_ERR "ppp_decompress_frame: no memory\n");
			goto err;
		}
		/* the decompressor still expects the A/C bytes in the hdr */
		len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1833
				skb->len + 2, ns->data, obuff_size);
L
Linus Torvalds 已提交
1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873
		if (len < 0) {
			/* Pass the compressed frame to pppd as an
			   error indication. */
			if (len == DECOMP_FATALERROR)
				ppp->rstate |= SC_DC_FERROR;
			kfree_skb(ns);
			goto err;
		}

		kfree_skb(skb);
		skb = ns;
		skb_put(skb, len);
		skb_pull(skb, 2);	/* pull off the A/C bytes */

	} else {
		/* Uncompressed frame - pass to decompressor so it
		   can update its dictionary if necessary. */
		if (ppp->rcomp->incomp)
			ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
					   skb->len + 2);
	}

	return skb;

 err:
	ppp->rstate |= SC_DC_ERROR;
	ppp_receive_error(ppp);
	return skb;
}

#ifdef CONFIG_PPP_MULTILINK
/*
 * Receive a multilink frame.
 * We put it on the reconstruction queue and then pull off
 * as many completed frames as we can.
 */
static void
ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
{
	u32 mask, seq;
1874
	struct channel *ch;
L
Linus Torvalds 已提交
1875 1876
	int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;

1877
	if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
L
Linus Torvalds 已提交
1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914
		goto err;		/* no good, throw it away */

	/* Decode sequence number and begin/end bits */
	if (ppp->flags & SC_MP_SHORTSEQ) {
		seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
		mask = 0xfff;
	} else {
		seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
		mask = 0xffffff;
	}
	skb->BEbits = skb->data[2];
	skb_pull(skb, mphdrlen);	/* pull off PPP and MP headers */

	/*
	 * Do protocol ID decompression on the first fragment of each packet.
	 */
	if ((skb->BEbits & B) && (skb->data[0] & 1))
		*skb_push(skb, 1) = 0;

	/*
	 * Expand sequence number to 32 bits, making it as close
	 * as possible to ppp->minseq.
	 */
	seq |= ppp->minseq & ~mask;
	if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
		seq += mask + 1;
	else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
		seq -= mask + 1;	/* should never happen */
	skb->sequence = seq;
	pch->lastseq = seq;

	/*
	 * If this packet comes before the next one we were expecting,
	 * drop it.
	 */
	if (seq_before(seq, ppp->nextseq)) {
		kfree_skb(skb);
1915
		++ppp->dev->stats.rx_dropped;
L
Linus Torvalds 已提交
1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927
		ppp_receive_error(ppp);
		return;
	}

	/*
	 * Reevaluate minseq, the minimum over all channels of the
	 * last sequence number received on each channel.  Because of
	 * the increasing sequence number rule, we know that any fragment
	 * before `minseq' which hasn't arrived is never going to arrive.
	 * The list of channels can't change because we have the receive
	 * side of the ppp unit locked.
	 */
1928
	list_for_each_entry(ch, &ppp->channels, clist) {
L
Linus Torvalds 已提交
1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939
		if (seq_before(ch->lastseq, seq))
			seq = ch->lastseq;
	}
	if (seq_before(ppp->minseq, seq))
		ppp->minseq = seq;

	/* Put the fragment on the reconstruction queue */
	ppp_mp_insert(ppp, skb);

	/* If the queue is getting long, don't wait any longer for packets
	   before the start of the queue. */
1940 1941 1942 1943 1944
	if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
		struct sk_buff *skb = skb_peek(&ppp->mrq);
		if (seq_before(ppp->minseq, skb->sequence))
			ppp->minseq = skb->sequence;
	}
L
Linus Torvalds 已提交
1945 1946

	/* Pull completed packets off the queue and receive them. */
J
Joe Perches 已提交
1947
	while ((skb = ppp_mp_reconstruct(ppp)))
L
Linus Torvalds 已提交
1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
		ppp_receive_nonmp_frame(ppp, skb);

	return;

 err:
	kfree_skb(skb);
	ppp_receive_error(ppp);
}

/*
 * Insert a fragment on the MP reconstruction queue.
 * The queue is ordered by increasing sequence number.
 */
static void
ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
{
	struct sk_buff *p;
	struct sk_buff_head *list = &ppp->mrq;
	u32 seq = skb->sequence;

	/* N.B. we don't need to lock the list lock because we have the
	   ppp unit receive-side lock. */
1970
	skb_queue_walk(list, p) {
L
Linus Torvalds 已提交
1971 1972
		if (seq_before(seq, p->sequence))
			break;
1973
	}
1974
	__skb_queue_before(list, p, skb);
L
Linus Torvalds 已提交
1975 1976 1977 1978 1979 1980 1981 1982
}

/*
 * Reconstruct a packet from the MP fragment queue.
 * We go through increasing sequence numbers until we find a
 * complete packet, or we get to the sequence number for a fragment
 * which hasn't arrived but might still do so.
 */
S
Stephen Hemminger 已提交
1983
static struct sk_buff *
L
Linus Torvalds 已提交
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039
ppp_mp_reconstruct(struct ppp *ppp)
{
	u32 seq = ppp->nextseq;
	u32 minseq = ppp->minseq;
	struct sk_buff_head *list = &ppp->mrq;
	struct sk_buff *p, *next;
	struct sk_buff *head, *tail;
	struct sk_buff *skb = NULL;
	int lost = 0, len = 0;

	if (ppp->mrru == 0)	/* do nothing until mrru is set */
		return NULL;
	head = list->next;
	tail = NULL;
	for (p = head; p != (struct sk_buff *) list; p = next) {
		next = p->next;
		if (seq_before(p->sequence, seq)) {
			/* this can't happen, anyway ignore the skb */
			printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
			       p->sequence, seq);
			head = next;
			continue;
		}
		if (p->sequence != seq) {
			/* Fragment `seq' is missing.  If it is after
			   minseq, it might arrive later, so stop here. */
			if (seq_after(seq, minseq))
				break;
			/* Fragment `seq' is lost, keep going. */
			lost = 1;
			seq = seq_before(minseq, p->sequence)?
				minseq + 1: p->sequence;
			next = p;
			continue;
		}

		/*
		 * At this point we know that all the fragments from
		 * ppp->nextseq to seq are either present or lost.
		 * Also, there are no complete packets in the queue
		 * that have no missing fragments and end before this
		 * fragment.
		 */

		/* B bit set indicates this fragment starts a packet */
		if (p->BEbits & B) {
			head = p;
			lost = 0;
			len = 0;
		}

		len += p->len;

		/* Got a complete packet yet? */
		if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
			if (len > ppp->mrru + 2) {
2040
				++ppp->dev->stats.rx_length_errors;
L
Linus Torvalds 已提交
2041 2042 2043 2044 2045 2046 2047 2048
				printk(KERN_DEBUG "PPP: reconstructed packet"
				       " is too long (%d)\n", len);
			} else if (p == head) {
				/* fragment is complete packet - reuse skb */
				tail = p;
				skb = skb_get(p);
				break;
			} else if ((skb = dev_alloc_skb(len)) == NULL) {
2049
				++ppp->dev->stats.rx_missed_errors;
L
Linus Torvalds 已提交
2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077
				printk(KERN_DEBUG "PPP: no memory for "
				       "reconstructed packet");
			} else {
				tail = p;
				break;
			}
			ppp->nextseq = seq + 1;
		}

		/*
		 * If this is the ending fragment of a packet,
		 * and we haven't found a complete valid packet yet,
		 * we can discard up to and including this fragment.
		 */
		if (p->BEbits & E)
			head = next;

		++seq;
	}

	/* If we have a complete packet, copy it all into one skb. */
	if (tail != NULL) {
		/* If we have discarded any fragments,
		   signal a receive error. */
		if (head->sequence != ppp->nextseq) {
			if (ppp->debug & 1)
				printk(KERN_DEBUG "  missed pkts %u..%u\n",
				       ppp->nextseq, head->sequence-1);
2078
			++ppp->dev->stats.rx_dropped;
L
Linus Torvalds 已提交
2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104
			ppp_receive_error(ppp);
		}

		if (head != tail)
			/* copy to a single skb */
			for (p = head; p != tail->next; p = p->next)
				skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
		ppp->nextseq = tail->sequence + 1;
		head = tail->next;
	}

	/* Discard all the skbuffs that we have copied the data out of
	   or that we can't use. */
	while ((p = list->next) != head) {
		__skb_unlink(p, list);
		kfree_skb(p);
	}

	return skb;
}
#endif /* CONFIG_PPP_MULTILINK */

/*
 * Channel interface.
 */

2105 2106 2107 2108 2109 2110 2111 2112
/* Create a new, unattached ppp channel. */
int ppp_register_channel(struct ppp_channel *chan)
{
	return ppp_register_net_channel(current->nsproxy->net_ns, chan);
}

/* Create a new, unattached ppp channel for specified net. */
int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
L
Linus Torvalds 已提交
2113 2114
{
	struct channel *pch;
2115
	struct ppp_net *pn;
L
Linus Torvalds 已提交
2116

2117
	pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
J
Joe Perches 已提交
2118
	if (!pch)
L
Linus Torvalds 已提交
2119
		return -ENOMEM;
2120 2121 2122

	pn = ppp_pernet(net);

L
Linus Torvalds 已提交
2123 2124
	pch->ppp = NULL;
	pch->chan = chan;
2125
	pch->chan_net = net;
L
Linus Torvalds 已提交
2126 2127 2128 2129 2130 2131 2132 2133 2134
	chan->ppp = pch;
	init_ppp_file(&pch->file, CHANNEL);
	pch->file.hdrlen = chan->hdrlen;
#ifdef CONFIG_PPP_MULTILINK
	pch->lastseq = -1;
#endif /* CONFIG_PPP_MULTILINK */
	init_rwsem(&pch->chan_sem);
	spin_lock_init(&pch->downl);
	rwlock_init(&pch->upl);
2135 2136 2137 2138

	spin_lock_bh(&pn->all_channels_lock);
	pch->file.index = ++pn->last_channel_index;
	list_add(&pch->list, &pn->new_channels);
L
Linus Torvalds 已提交
2139
	atomic_inc(&channel_count);
2140 2141
	spin_unlock_bh(&pn->all_channels_lock);

L
Linus Torvalds 已提交
2142 2143 2144 2145 2146 2147 2148 2149 2150 2151
	return 0;
}

/*
 * Return the index of a channel.
 */
int ppp_channel_index(struct ppp_channel *chan)
{
	struct channel *pch = chan->ppp;

J
Joe Perches 已提交
2152
	if (pch)
L
Linus Torvalds 已提交
2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164
		return pch->file.index;
	return -1;
}

/*
 * Return the PPP unit number to which a channel is connected.
 */
int ppp_unit_number(struct ppp_channel *chan)
{
	struct channel *pch = chan->ppp;
	int unit = -1;

J
Joe Perches 已提交
2165
	if (pch) {
L
Linus Torvalds 已提交
2166
		read_lock_bh(&pch->upl);
J
Joe Perches 已提交
2167
		if (pch->ppp)
L
Linus Torvalds 已提交
2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181
			unit = pch->ppp->file.index;
		read_unlock_bh(&pch->upl);
	}
	return unit;
}

/*
 * Disconnect a channel from the generic layer.
 * This must be called in process context.
 */
void
ppp_unregister_channel(struct ppp_channel *chan)
{
	struct channel *pch = chan->ppp;
2182
	struct ppp_net *pn;
L
Linus Torvalds 已提交
2183

J
Joe Perches 已提交
2184
	if (!pch)
L
Linus Torvalds 已提交
2185
		return;		/* should never happen */
2186

L
Linus Torvalds 已提交
2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198
	chan->ppp = NULL;

	/*
	 * This ensures that we have returned from any calls into the
	 * the channel's start_xmit or ioctl routine before we proceed.
	 */
	down_write(&pch->chan_sem);
	spin_lock_bh(&pch->downl);
	pch->chan = NULL;
	spin_unlock_bh(&pch->downl);
	up_write(&pch->chan_sem);
	ppp_disconnect_channel(pch);
2199 2200 2201

	pn = ppp_pernet(pch->chan_net);
	spin_lock_bh(&pn->all_channels_lock);
L
Linus Torvalds 已提交
2202
	list_del(&pch->list);
2203 2204
	spin_unlock_bh(&pn->all_channels_lock);

L
Linus Torvalds 已提交
2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
	pch->file.dead = 1;
	wake_up_interruptible(&pch->file.rwait);
	if (atomic_dec_and_test(&pch->file.refcnt))
		ppp_destroy_channel(pch);
}

/*
 * Callback from a channel when it can accept more to transmit.
 * This should be called at BH/softirq level, not interrupt level.
 */
void
ppp_output_wakeup(struct ppp_channel *chan)
{
	struct channel *pch = chan->ppp;

J
Joe Perches 已提交
2220
	if (!pch)
L
Linus Torvalds 已提交
2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248
		return;
	ppp_channel_push(pch);
}

/*
 * Compression control.
 */

/* Process the PPPIOCSCOMPRESS ioctl. */
static int
ppp_set_compress(struct ppp *ppp, unsigned long arg)
{
	int err;
	struct compressor *cp, *ocomp;
	struct ppp_option_data data;
	void *state, *ostate;
	unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];

	err = -EFAULT;
	if (copy_from_user(&data, (void __user *) arg, sizeof(data))
	    || (data.length <= CCP_MAX_OPTION_LENGTH
		&& copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
		goto out;
	err = -EINVAL;
	if (data.length > CCP_MAX_OPTION_LENGTH
	    || ccp_option[1] < 2 || ccp_option[1] > data.length)
		goto out;

J
Johannes Berg 已提交
2249 2250 2251
	cp = try_then_request_module(
		find_compressor(ccp_option[0]),
		"ppp-compress-%d", ccp_option[0]);
J
Joe Perches 已提交
2252
	if (!cp)
L
Linus Torvalds 已提交
2253 2254 2255 2256 2257
		goto out;

	err = -ENOBUFS;
	if (data.transmit) {
		state = cp->comp_alloc(ccp_option, data.length);
J
Joe Perches 已提交
2258
		if (state) {
L
Linus Torvalds 已提交
2259 2260 2261 2262 2263 2264 2265
			ppp_xmit_lock(ppp);
			ppp->xstate &= ~SC_COMP_RUN;
			ocomp = ppp->xcomp;
			ostate = ppp->xc_state;
			ppp->xcomp = cp;
			ppp->xc_state = state;
			ppp_xmit_unlock(ppp);
J
Joe Perches 已提交
2266
			if (ostate) {
L
Linus Torvalds 已提交
2267 2268 2269 2270 2271 2272 2273 2274 2275
				ocomp->comp_free(ostate);
				module_put(ocomp->owner);
			}
			err = 0;
		} else
			module_put(cp->owner);

	} else {
		state = cp->decomp_alloc(ccp_option, data.length);
J
Joe Perches 已提交
2276
		if (state) {
L
Linus Torvalds 已提交
2277 2278 2279 2280 2281 2282 2283
			ppp_recv_lock(ppp);
			ppp->rstate &= ~SC_DECOMP_RUN;
			ocomp = ppp->rcomp;
			ostate = ppp->rc_state;
			ppp->rcomp = cp;
			ppp->rc_state = state;
			ppp_recv_unlock(ppp);
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			if (ostate) {
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				ocomp->decomp_free(ostate);
				module_put(ocomp->owner);
			}
			err = 0;
		} else
			module_put(cp->owner);
	}

 out:
	return err;
}

/*
 * Look at a CCP packet and update our state accordingly.
 * We assume the caller has the xmit or recv path locked.
 */
static void
ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
{
	unsigned char *dp;
	int len;

	if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
		return;	/* no header */
	dp = skb->data + 2;

	switch (CCP_CODE(dp)) {
	case CCP_CONFREQ:

2314
		/* A ConfReq starts negotiation of compression
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		 * in one direction of transmission,
		 * and hence brings it down...but which way?
		 *
		 * Remember:
		 * A ConfReq indicates what the sender would like to receive
		 */
		if(inbound)
			/* He is proposing what I should send */
			ppp->xstate &= ~SC_COMP_RUN;
2324
		else
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			/* I am proposing to what he should send */
			ppp->rstate &= ~SC_DECOMP_RUN;
2327

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		break;
2329

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	case CCP_TERMREQ:
	case CCP_TERMACK:
		/*
2333
		 * CCP is going down, both directions of transmission
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		 */
		ppp->rstate &= ~SC_DECOMP_RUN;
		ppp->xstate &= ~SC_COMP_RUN;
		break;

	case CCP_CONFACK:
		if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
			break;
		len = CCP_LENGTH(dp);
		if (!pskb_may_pull(skb, len + 2))
			return;		/* too short */
		dp += CCP_HDRLEN;
		len -= CCP_HDRLEN;
		if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
			break;
		if (inbound) {
			/* we will start receiving compressed packets */
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			if (!ppp->rc_state)
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				break;
			if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
					ppp->file.index, 0, ppp->mru, ppp->debug)) {
				ppp->rstate |= SC_DECOMP_RUN;
				ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
			}
		} else {
			/* we will soon start sending compressed packets */
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			if (!ppp->xc_state)
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				break;
			if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
					ppp->file.index, 0, ppp->debug))
				ppp->xstate |= SC_COMP_RUN;
		}
		break;

	case CCP_RESETACK:
		/* reset the [de]compressor */
		if ((ppp->flags & SC_CCP_UP) == 0)
			break;
		if (inbound) {
			if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
				ppp->rcomp->decomp_reset(ppp->rc_state);
				ppp->rstate &= ~SC_DC_ERROR;
			}
		} else {
			if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
				ppp->xcomp->comp_reset(ppp->xc_state);
		}
		break;
	}
}

/* Free up compression resources. */
static void
ppp_ccp_closed(struct ppp *ppp)
{
	void *xstate, *rstate;
	struct compressor *xcomp, *rcomp;

	ppp_lock(ppp);
	ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
	ppp->xstate = 0;
	xcomp = ppp->xcomp;
	xstate = ppp->xc_state;
	ppp->xc_state = NULL;
	ppp->rstate = 0;
	rcomp = ppp->rcomp;
	rstate = ppp->rc_state;
	ppp->rc_state = NULL;
	ppp_unlock(ppp);

	if (xstate) {
		xcomp->comp_free(xstate);
		module_put(xcomp->owner);
	}
	if (rstate) {
		rcomp->decomp_free(rstate);
		module_put(rcomp->owner);
	}
}

/* List of compressors. */
static LIST_HEAD(compressor_list);
static DEFINE_SPINLOCK(compressor_list_lock);

struct compressor_entry {
	struct list_head list;
	struct compressor *comp;
};

static struct compressor_entry *
find_comp_entry(int proto)
{
	struct compressor_entry *ce;

2428
	list_for_each_entry(ce, &compressor_list, list) {
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		if (ce->comp->compress_proto == proto)
			return ce;
	}
	return NULL;
}

/* Register a compressor */
int
ppp_register_compressor(struct compressor *cp)
{
	struct compressor_entry *ce;
	int ret;
	spin_lock(&compressor_list_lock);
	ret = -EEXIST;
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2443
	if (find_comp_entry(cp->compress_proto))
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		goto out;
	ret = -ENOMEM;
	ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
J
Joe Perches 已提交
2447
	if (!ce)
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2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464
		goto out;
	ret = 0;
	ce->comp = cp;
	list_add(&ce->list, &compressor_list);
 out:
	spin_unlock(&compressor_list_lock);
	return ret;
}

/* Unregister a compressor */
void
ppp_unregister_compressor(struct compressor *cp)
{
	struct compressor_entry *ce;

	spin_lock(&compressor_list_lock);
	ce = find_comp_entry(cp->compress_proto);
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	if (ce && ce->comp == cp) {
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2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480
		list_del(&ce->list);
		kfree(ce);
	}
	spin_unlock(&compressor_list_lock);
}

/* Find a compressor. */
static struct compressor *
find_compressor(int type)
{
	struct compressor_entry *ce;
	struct compressor *cp = NULL;

	spin_lock(&compressor_list_lock);
	ce = find_comp_entry(type);
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Joe Perches 已提交
2481
	if (ce) {
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2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499
		cp = ce->comp;
		if (!try_module_get(cp->owner))
			cp = NULL;
	}
	spin_unlock(&compressor_list_lock);
	return cp;
}

/*
 * Miscelleneous stuff.
 */

static void
ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
{
	struct slcompress *vj = ppp->vj;

	memset(st, 0, sizeof(*st));
2500 2501 2502 2503 2504 2505
	st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
	st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
	st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
	st->p.ppp_opackets = ppp->dev->stats.tx_packets;
	st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
	st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
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Joe Perches 已提交
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	if (!vj)
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2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528
		return;
	st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
	st->vj.vjs_compressed = vj->sls_o_compressed;
	st->vj.vjs_searches = vj->sls_o_searches;
	st->vj.vjs_misses = vj->sls_o_misses;
	st->vj.vjs_errorin = vj->sls_i_error;
	st->vj.vjs_tossed = vj->sls_i_tossed;
	st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
	st->vj.vjs_compressedin = vj->sls_i_compressed;
}

/*
 * Stuff for handling the lists of ppp units and channels
 * and for initialization.
 */

/*
 * Create a new ppp interface unit.  Fails if it can't allocate memory
 * or if there is already a unit with the requested number.
 * unit == -1 means allocate a new number.
 */
static struct ppp *
2529
ppp_create_interface(struct net *net, int unit, int *retp)
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{
	struct ppp *ppp;
2532
	struct ppp_net *pn;
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	struct net_device *dev = NULL;
	int ret = -ENOMEM;
	int i;

2537
	dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
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2538 2539 2540
	if (!dev)
		goto out1;

2541 2542
	pn = ppp_pernet(net);

2543 2544
	ppp = netdev_priv(dev);
	ppp->dev = dev;
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2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557
	ppp->mru = PPP_MRU;
	init_ppp_file(&ppp->file, INTERFACE);
	ppp->file.hdrlen = PPP_HDRLEN - 2;	/* don't count proto bytes */
	for (i = 0; i < NUM_NP; ++i)
		ppp->npmode[i] = NPMODE_PASS;
	INIT_LIST_HEAD(&ppp->channels);
	spin_lock_init(&ppp->rlock);
	spin_lock_init(&ppp->wlock);
#ifdef CONFIG_PPP_MULTILINK
	ppp->minseq = -1;
	skb_queue_head_init(&ppp->mrq);
#endif /* CONFIG_PPP_MULTILINK */

2558 2559 2560 2561 2562 2563
	/*
	 * drum roll: don't forget to set
	 * the net device is belong to
	 */
	dev_net_set(dev, net);

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	ret = -EEXIST;
2565
	mutex_lock(&pn->all_ppp_mutex);
2566 2567

	if (unit < 0) {
2568
		unit = unit_get(&pn->units_idr, ppp);
2569 2570 2571 2572 2573
		if (unit < 0) {
			*retp = unit;
			goto out2;
		}
	} else {
2574
		if (unit_find(&pn->units_idr, unit))
2575
			goto out2; /* unit already exists */
2576 2577 2578 2579 2580 2581 2582 2583 2584
		/*
		 * if caller need a specified unit number
		 * lets try to satisfy him, otherwise --
		 * he should better ask us for new unit number
		 *
		 * NOTE: yes I know that returning EEXIST it's not
		 * fair but at least pppd will ask us to allocate
		 * new unit in this case so user is happy :)
		 */
2585
		unit = unit_set(&pn->units_idr, ppp, unit);
2586
		if (unit < 0)
2587 2588
			goto out2;
	}
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	/* Initialize the new ppp unit */
	ppp->file.index = unit;
	sprintf(dev->name, "ppp%d", unit);

	ret = register_netdev(dev);
	if (ret != 0) {
2596
		unit_put(&pn->units_idr, unit);
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		printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
		       dev->name, ret);
		goto out2;
	}

2602 2603
	ppp->ppp_net = net;

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	atomic_inc(&ppp_unit_count);
2605
	mutex_unlock(&pn->all_ppp_mutex);
2606

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	*retp = 0;
	return ppp;

out2:
2611
	mutex_unlock(&pn->all_ppp_mutex);
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	free_netdev(dev);
out1:
	*retp = ret;
	return NULL;
}

/*
 * Initialize a ppp_file structure.
 */
static void
init_ppp_file(struct ppp_file *pf, int kind)
{
	pf->kind = kind;
	skb_queue_head_init(&pf->xq);
	skb_queue_head_init(&pf->rq);
	atomic_set(&pf->refcnt, 1);
	init_waitqueue_head(&pf->rwait);
}

/*
 * Take down a ppp interface unit - called when the owning file
 * (the one that created the unit) is closed or detached.
 */
static void ppp_shutdown_interface(struct ppp *ppp)
{
2637 2638 2639 2640 2641
	struct ppp_net *pn;

	pn = ppp_pernet(ppp->ppp_net);
	mutex_lock(&pn->all_ppp_mutex);

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	/* This will call dev_close() for us. */
2643 2644 2645 2646 2647 2648 2649 2650
	ppp_lock(ppp);
	if (!ppp->closing) {
		ppp->closing = 1;
		ppp_unlock(ppp);
		unregister_netdev(ppp->dev);
	} else
		ppp_unlock(ppp);

2651
	unit_put(&pn->units_idr, ppp->file.index);
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	ppp->file.dead = 1;
	ppp->owner = NULL;
	wake_up_interruptible(&ppp->file.rwait);
2655 2656

	mutex_unlock(&pn->all_ppp_mutex);
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}

/*
 * Free the memory used by a ppp unit.  This is only called once
 * there are no channels connected to the unit and no file structs
 * that reference the unit.
 */
static void ppp_destroy_interface(struct ppp *ppp)
{
	atomic_dec(&ppp_unit_count);

	if (!ppp->file.dead || ppp->n_channels) {
		/* "can't happen" */
		printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
		       "n_channels=%d !\n", ppp, ppp->file.dead,
		       ppp->n_channels);
		return;
	}

	ppp_ccp_closed(ppp);
	if (ppp->vj) {
		slhc_free(ppp->vj);
		ppp->vj = NULL;
	}
	skb_queue_purge(&ppp->file.xq);
	skb_queue_purge(&ppp->file.rq);
#ifdef CONFIG_PPP_MULTILINK
	skb_queue_purge(&ppp->mrq);
#endif /* CONFIG_PPP_MULTILINK */
#ifdef CONFIG_PPP_FILTER
2687 2688 2689 2690
	kfree(ppp->pass_filter);
	ppp->pass_filter = NULL;
	kfree(ppp->active_filter);
	ppp->active_filter = NULL;
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#endif /* CONFIG_PPP_FILTER */

2693
	kfree_skb(ppp->xmit_pending);
2694

2695
	free_netdev(ppp->dev);
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}

/*
 * Locate an existing ppp unit.
2700
 * The caller should have locked the all_ppp_mutex.
L
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 */
static struct ppp *
2703
ppp_find_unit(struct ppp_net *pn, int unit)
L
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2704
{
2705
	return unit_find(&pn->units_idr, unit);
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}

/*
 * Locate an existing ppp channel.
 * The caller should have locked the all_channels_lock.
 * First we look in the new_channels list, then in the
 * all_channels list.  If found in the new_channels list,
 * we move it to the all_channels list.  This is for speed
 * when we have a lot of channels in use.
 */
static struct channel *
2717
ppp_find_channel(struct ppp_net *pn, int unit)
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{
	struct channel *pch;

2721
	list_for_each_entry(pch, &pn->new_channels, list) {
L
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2722
		if (pch->file.index == unit) {
2723
			list_move(&pch->list, &pn->all_channels);
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			return pch;
		}
	}
2727 2728

	list_for_each_entry(pch, &pn->all_channels, list) {
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2729 2730 2731
		if (pch->file.index == unit)
			return pch;
	}
2732

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	return NULL;
}

/*
 * Connect a PPP channel to a PPP interface unit.
 */
static int
ppp_connect_channel(struct channel *pch, int unit)
{
	struct ppp *ppp;
2743
	struct ppp_net *pn;
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2744 2745 2746
	int ret = -ENXIO;
	int hdrlen;

2747 2748 2749 2750
	pn = ppp_pernet(pch->chan_net);

	mutex_lock(&pn->all_ppp_mutex);
	ppp = ppp_find_unit(pn, unit);
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2751
	if (!ppp)
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2752 2753 2754
		goto out;
	write_lock_bh(&pch->upl);
	ret = -EINVAL;
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2755
	if (pch->ppp)
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		goto outl;

	ppp_lock(ppp);
	if (pch->file.hdrlen > ppp->file.hdrlen)
		ppp->file.hdrlen = pch->file.hdrlen;
	hdrlen = pch->file.hdrlen + 2;	/* for protocol bytes */
2762
	if (hdrlen > ppp->dev->hard_header_len)
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		ppp->dev->hard_header_len = hdrlen;
	list_add_tail(&pch->clist, &ppp->channels);
	++ppp->n_channels;
	pch->ppp = ppp;
	atomic_inc(&ppp->file.refcnt);
	ppp_unlock(ppp);
	ret = 0;

 outl:
	write_unlock_bh(&pch->upl);
 out:
2774
	mutex_unlock(&pn->all_ppp_mutex);
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	return ret;
}

/*
 * Disconnect a channel from its ppp unit.
 */
static int
ppp_disconnect_channel(struct channel *pch)
{
	struct ppp *ppp;
	int err = -EINVAL;

	write_lock_bh(&pch->upl);
	ppp = pch->ppp;
	pch->ppp = NULL;
	write_unlock_bh(&pch->upl);
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2791
	if (ppp) {
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		/* remove it from the ppp unit's list */
		ppp_lock(ppp);
		list_del(&pch->clist);
		if (--ppp->n_channels == 0)
			wake_up_interruptible(&ppp->file.rwait);
		ppp_unlock(ppp);
		if (atomic_dec_and_test(&ppp->file.refcnt))
			ppp_destroy_interface(ppp);
		err = 0;
	}
	return err;
}

/*
 * Free up the resources used by a ppp channel.
 */
static void ppp_destroy_channel(struct channel *pch)
{
	atomic_dec(&channel_count);

	if (!pch->file.dead) {
		/* "can't happen" */
		printk(KERN_ERR "ppp: destroying undead channel %p !\n",
		       pch);
		return;
	}
	skb_queue_purge(&pch->file.xq);
	skb_queue_purge(&pch->file.rq);
	kfree(pch);
}

static void __exit ppp_cleanup(void)
{
	/* should never happen */
	if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
		printk(KERN_ERR "PPP: removing module but units remain!\n");
2828
	unregister_chrdev(PPP_MAJOR, "ppp");
2829
	device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2830
	class_destroy(ppp_class);
2831
	unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
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}

/*
2835 2836
 * Units handling. Caller must protect concurrent access
 * by holding all_ppp_mutex
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2837
 */
2838

2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861
/* associate pointer with specified number */
static int unit_set(struct idr *p, void *ptr, int n)
{
	int unit, err;

again:
	if (!idr_pre_get(p, GFP_KERNEL)) {
		printk(KERN_ERR "PPP: No free memory for idr\n");
		return -ENOMEM;
	}

	err = idr_get_new_above(p, ptr, n, &unit);
	if (err == -EAGAIN)
		goto again;

	if (unit != n) {
		idr_remove(p, unit);
		return -EINVAL;
	}

	return unit;
}

2862 2863
/* get new free unit number and associate pointer with it */
static int unit_get(struct idr *p, void *ptr)
L
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2864
{
2865
	int unit, err;
L
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2866

2867
again:
2868 2869
	if (!idr_pre_get(p, GFP_KERNEL)) {
		printk(KERN_ERR "PPP: No free memory for idr\n");
2870
		return -ENOMEM;
L
Linus Torvalds 已提交
2871 2872
	}

2873 2874 2875
	err = idr_get_new_above(p, ptr, 0, &unit);
	if (err == -EAGAIN)
		goto again;
L
Linus Torvalds 已提交
2876

2877
	return unit;
L
Linus Torvalds 已提交
2878 2879
}

2880 2881
/* put unit number back to a pool */
static void unit_put(struct idr *p, int n)
L
Linus Torvalds 已提交
2882
{
2883
	idr_remove(p, n);
L
Linus Torvalds 已提交
2884 2885
}

2886 2887
/* get pointer associated with the number */
static void *unit_find(struct idr *p, int n)
L
Linus Torvalds 已提交
2888
{
2889
	return idr_find(p, n);
L
Linus Torvalds 已提交
2890 2891 2892 2893 2894 2895 2896
}

/* Module/initialization stuff */

module_init(ppp_init);
module_exit(ppp_cleanup);

2897
EXPORT_SYMBOL(ppp_register_net_channel);
L
Linus Torvalds 已提交
2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909
EXPORT_SYMBOL(ppp_register_channel);
EXPORT_SYMBOL(ppp_unregister_channel);
EXPORT_SYMBOL(ppp_channel_index);
EXPORT_SYMBOL(ppp_unit_number);
EXPORT_SYMBOL(ppp_input);
EXPORT_SYMBOL(ppp_input_error);
EXPORT_SYMBOL(ppp_output_wakeup);
EXPORT_SYMBOL(ppp_register_compressor);
EXPORT_SYMBOL(ppp_unregister_compressor);
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
MODULE_ALIAS("/dev/ppp");