ppp_generic.c 64.9 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>

#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 */
};

/*
 * 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 */
	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 */
#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.
 */

/*
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 * all_ppp_mutex protects the all_ppp_units mapping.
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 * It also ensures that finding a ppp unit in the all_ppp_units map
 * and updating its file.refcnt field is atomic.
 */
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static DEFINE_MUTEX(all_ppp_mutex);
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static atomic_t ppp_unit_count = ATOMIC_INIT(0);
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static DEFINE_IDR(ppp_units_idr);
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/*
 * all_channels_lock protects all_channels and last_channel_index,
 * and the atomicity of find a channel and updating its file.refcnt
 * field.
 */
static DEFINE_SPINLOCK(all_channels_lock);
static LIST_HEAD(all_channels);
static LIST_HEAD(new_channels);
static int last_channel_index;
static atomic_t channel_count = ATOMIC_INIT(0);

/* 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. */
static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
				unsigned int cmd, unsigned long arg);
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);
static struct ppp *ppp_create_interface(int unit, int *retp);
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);
static struct ppp *ppp_find_unit(int unit);
static struct channel *ppp_find_channel(int unit);
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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/* 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(pf, file, cmd, arg);

	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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		if (atomic_long_read(&file->f_count) <= 2) {
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			ppp_release(NULL, file);
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			err = 0;
		} else
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			printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
			       atomic_long_read(&file->f_count));
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		unlock_kernel();
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		return err;
	}

	if (pf->kind == CHANNEL) {
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		struct channel *pch;
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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) {
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			printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
			err = -ENOMEM;
			break;
		}
		ppp_lock(ppp);
J
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689
		if (ppp->vj)
L
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			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;
}

static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
				unsigned int cmd, unsigned long arg)
{
	int unit, err = -EFAULT;
	struct ppp *ppp;
	struct channel *chan;
	int __user *p = (int __user *)arg;

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	lock_kernel();
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	switch (cmd) {
	case PPPIOCNEWUNIT:
		/* Create a new ppp unit */
		if (get_user(unit, p))
			break;
		ppp = ppp_create_interface(unit, &err);
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		if (!ppp)
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			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;
795
		mutex_lock(&all_ppp_mutex);
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		err = -ENXIO;
		ppp = ppp_find_unit(unit);
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		if (ppp) {
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			atomic_inc(&ppp->file.refcnt);
			file->private_data = &ppp->file;
			err = 0;
		}
803
		mutex_unlock(&all_ppp_mutex);
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		break;

	case PPPIOCATTCHAN:
		if (get_user(unit, p))
			break;
		spin_lock_bh(&all_channels_lock);
		err = -ENXIO;
		chan = ppp_find_channel(unit);
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Joe Perches 已提交
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		if (chan) {
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			atomic_inc(&chan->file.refcnt);
			file->private_data = &chan->file;
			err = 0;
		}
		spin_unlock_bh(&all_channels_lock);
		break;

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

827
static const struct file_operations ppp_device_fops = {
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	.owner		= THIS_MODULE,
	.read		= ppp_read,
	.write		= ppp_write,
	.poll		= ppp_poll,
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	.unlocked_ioctl	= ppp_ioctl,
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	.open		= ppp_open,
	.release	= ppp_release
};

#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");
	err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
	if (!err) {
848
		ppp_class = class_create(THIS_MODULE, "ppp");
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		if (IS_ERR(ppp_class)) {
			err = PTR_ERR(ppp_class);
			goto out_chrdev;
		}
853 854
		device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL,
			      "ppp");
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	}

out:
	if (err)
		printk(KERN_ERR "failed to register PPP device (%d)\n", err);
	return err;

out_chrdev:
	unregister_chrdev(PPP_MAJOR, "ppp");
	goto out;
}

/*
 * Network interface unit routines.
 */
static int
ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
873
	struct ppp *ppp = netdev_priv(dev);
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	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. */
896 897 898
	if (skb_cow_head(skb, PPP_HDRLEN))
		goto outf;

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	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);
	return 0;

 outf:
	kfree_skb(skb);
911
	++ppp->dev->stats.tx_dropped;
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	return 0;
}

static int
ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
918
	struct ppp *ppp = netdev_priv(dev);
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	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
935
		if (ppp->xc_state)
L
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936
			ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
J
Joe Perches 已提交
937
		if (ppp->rc_state)
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938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957
			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
958
static const struct net_device_ops ppp_netdev_ops = {
959 960
	.ndo_start_xmit = ppp_start_xmit,
	.ndo_do_ioctl   = ppp_net_ioctl,
S
Stephen Hemminger 已提交
961 962
};

L
Linus Torvalds 已提交
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static void ppp_setup(struct net_device *dev)
{
S
Stephen Hemminger 已提交
965
	dev->netdev_ops = &ppp_netdev_ops;
L
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966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987
	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;
}

/*
 * 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);
988
	if (!ppp->closing) {
L
Linus Torvalds 已提交
989
		ppp_push(ppp);
J
Joe Perches 已提交
990 991
		while (!ppp->xmit_pending
		       && (skb = skb_dequeue(&ppp->file.xq)))
L
Linus Torvalds 已提交
992 993 994
			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
995
		if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
L
Linus Torvalds 已提交
996 997 998 999 1000
			netif_wake_queue(ppp->dev);
	}
	ppp_xmit_unlock(ppp);
}

1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050
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;
}

L
Linus Torvalds 已提交
1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089
/*
 * 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 */
	}

1090 1091
	++ppp->dev->stats.tx_packets;
	ppp->dev->stats.tx_bytes += skb->len - 2;
L
Linus Torvalds 已提交
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	switch (proto) {
	case PPP_IP:
J
Joe Perches 已提交
1095
		if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
L
Linus Torvalds 已提交
1096 1097 1098 1099
			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
1100
		if (!new_skb) {
L
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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
			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 */
J
Joe Perches 已提交
1135
	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
L
Linus Torvalds 已提交
1136
	    && proto != PPP_LCP && proto != PPP_CCP) {
1137 1138 1139
		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");
L
Linus Torvalds 已提交
1140 1141
			goto drop;
		}
1142 1143 1144
		skb = pad_compress_skb(ppp, skb);
		if (!skb)
			goto drop;
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1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163
	}

	/*
	 * 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:
1164 1165
	if (skb)
		kfree_skb(skb);
1166
	++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)
L
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1181 1182 1183 1184 1185 1186 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 1221 1222 1223 1224 1225 1226
		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)
{
1227
	int len, fragsize;
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	int i, bits, hdrlen, mtu;
1229 1230 1231
	int flen;
	int navail, nfree;
	int nbigger;
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1232 1233 1234 1235 1236 1237
	unsigned char *p, *q;
	struct list_head *list;
	struct channel *pch;
	struct sk_buff *frag;
	struct ppp_channel *chan;

1238 1239
	nfree = 0;	/* # channels which have no packet already queued */
	navail = 0;	/* total # of usable channels (not deregistered) */
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	hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1241
	i = 0;
1242
	list_for_each_entry(pch, &ppp->channels, clist) {
1243 1244
		navail += pch->avail = (pch->chan != NULL);
		if (pch->avail) {
1245 1246
			if (skb_queue_empty(&pch->file.xq) ||
			    !pch->had_frag) {
1247 1248
				pch->avail = 2;
				++nfree;
L
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1249
			}
1250 1251
			if (!pch->had_frag && i < ppp->nxchan)
				ppp->nxchan = i;
L
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1252
		}
1253
		++i;
L
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1254
	}
1255 1256 1257 1258 1259 1260 1261

	/*
	 * 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.
	 */
	if (nfree == 0 || nfree < navail / 2)
L
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		return 0;	/* can't take now, leave it in xmit_pending */

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

1272 1273 1274 1275 1276 1277 1278
	/*
	 * Decide on fragment size.
	 * We create a fragment for each free channel regardless of
	 * how small they are (i.e. even 0 length) in order to minimize
	 * the time that it will take to detect when a channel drops
	 * a fragment.
	 */
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	fragsize = len;
1280
	if (nfree > 1)
1281
		fragsize = DIV_ROUND_UP(fragsize, nfree);
1282 1283 1284
	/* nbigger channels get fragsize bytes, the rest get fragsize-1,
	   except if nbigger==0, then they all get fragsize. */
	nbigger = len % nfree;
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	/* skip to the channel after the one we last used
	   and start at that one */
1288
	list = &ppp->channels;
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	for (i = 0; i < ppp->nxchan; ++i) {
		list = list->next;
		if (list == &ppp->channels) {
			i = 0;
			break;
		}
	}

	/* create a fragment for each channel */
	bits = B;
1299
	while (nfree > 0 || len > 0) {
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		list = list->next;
		if (list == &ppp->channels) {
			i = 0;
			continue;
		}
		pch = list_entry(list, struct channel, clist);
		++i;
		if (!pch->avail)
			continue;

1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321
		/*
		 * Skip this channel if it has a fragment pending already and
		 * we haven't given a fragment to all of the free channels.
		 */
		if (pch->avail == 1) {
			if (nfree > 0)
				continue;
		} else {
			--nfree;
			pch->avail = 1;
		}

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		/* check the channel's mtu and whether it is still attached. */
		spin_lock_bh(&pch->downl);
1324 1325
		if (pch->chan == NULL) {
			/* can't use this channel, it's being deregistered */
L
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			spin_unlock_bh(&pch->downl);
			pch->avail = 0;
1328
			if (--navail == 0)
L
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				break;
			continue;
		}

		/*
1334 1335 1336 1337
		 * Create a fragment for this channel of
		 * min(max(mtu+2-hdrlen, 4), fragsize, len) bytes.
		 * If mtu+2-hdrlen < 4, that is a ridiculously small
		 * MTU, so we use mtu = 2 + hdrlen.
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		 */
		if (fragsize > len)
			fragsize = len;
1341 1342 1343 1344 1345 1346 1347 1348 1349
		flen = fragsize;
		mtu = pch->chan->mtu + 2 - hdrlen;
		if (mtu < 4)
			mtu = 4;
		if (flen > mtu)
			flen = mtu;
		if (flen == len && nfree == 0)
			bits |= E;
		frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
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		if (!frag)
1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364
			goto noskb;
		q = skb_put(frag, flen + hdrlen);

		/* make the MP header */
		q[0] = PPP_MP >> 8;
		q[1] = PPP_MP;
		if (ppp->flags & SC_MP_XSHORTSEQ) {
			q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
			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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		}
1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382

		/*
		 * Copy the data in.
		 * Unfortunately there is a bug in older versions of
		 * the Linux PPP multilink reconstruction code where it
		 * drops 0-length fragments.  Therefore we make sure the
		 * fragment has at least one byte of data.  Any bytes
		 * we add in this situation will end up as padding on the
		 * end of the reconstructed packet.
		 */
		if (flen == 0)
			*skb_put(frag, 1) = 0;
		else
			memcpy(q + hdrlen, p, flen);

		/* try to send it down the channel */
		chan = pch->chan;
1383 1384
		if (!skb_queue_empty(&pch->file.xq) ||
		    !chan->ops->start_xmit(chan, frag))
1385 1386 1387 1388 1389 1390
			skb_queue_tail(&pch->file.xq, frag);
		pch->had_frag = 1;
		p += flen;
		len -= flen;
		++ppp->nxseq;
		bits = 0;
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		spin_unlock_bh(&pch->downl);
1392 1393 1394 1395

		if (--nbigger == 0 && fragsize > 0)
			--fragsize;
	}
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	ppp->nxchan = i;

	return 1;

 noskb:
	spin_unlock_bh(&pch->downl);
	if (ppp->debug & 1)
		printk(KERN_ERR "PPP: no memory (fragment)\n");
1404
	++ppp->dev->stats.tx_errors;
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	++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
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	if (pch->chan) {
1421
		while (!skb_queue_empty(&pch->file.xq)) {
L
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			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 */
1435
	if (skb_queue_empty(&pch->file.xq)) {
L
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		read_lock_bh(&pch->upl);
		ppp = pch->ppp;
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		if (ppp)
L
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			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);
1456
	if (!ppp->closing)
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		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
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	if (!pch || skb->len == 0) {
L
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1470 1471 1472
		kfree_skb(skb);
		return;
	}
1473

L
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	proto = PPP_PROTO(skb);
	read_lock_bh(&pch->upl);
J
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	if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
L
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		/* 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
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1481
		       && (skb = skb_dequeue(&pch->file.rq)))
L
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1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496
			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
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	if (!pch)
L
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1498 1499 1500
		return;

	read_lock_bh(&pch->upl);
J
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1501
	if (pch->ppp) {
L
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1502
		skb = alloc_skb(0, GFP_ATOMIC);
J
Joe Perches 已提交
1503
		if (skb) {
L
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1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518
			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)
{
1519
	if (pskb_may_pull(skb, 2)) {
L
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1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531
#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 */
1532
		++ppp->dev->stats.rx_length_errors;
L
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1533 1534 1535 1536 1537 1538 1539 1540

	kfree_skb(skb);
	ppp_receive_error(ppp);
}

static void
ppp_receive_error(struct ppp *ppp)
{
1541
	++ppp->dev->stats.rx_errors;
J
Joe Perches 已提交
1542
	if (ppp->vj)
L
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1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556
		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
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1557
	if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
L
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1558 1559 1560
	    && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
		skb = ppp_decompress_frame(ppp, skb);

1561 1562 1563
	if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
		goto err;

L
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1564 1565 1566 1567
	proto = PPP_PROTO(skb);
	switch (proto) {
	case PPP_VJC_COMP:
		/* decompress VJ compressed packets */
J
Joe Perches 已提交
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		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
L
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1569 1570
			goto err;

1571
		if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
L
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1572 1573
			/* copy to a new sk_buff with more tailroom */
			ns = dev_alloc_skb(skb->len + 128);
J
Joe Perches 已提交
1574
			if (!ns) {
L
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1575 1576 1577 1578 1579 1580 1581 1582
				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;
		}
1583 1584
		else
			skb->ip_summed = CHECKSUM_NONE;
L
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1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599

		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
1600
		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
L
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1601
			goto err;
1602

L
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1603 1604 1605
		/* Until we fix the decompressor need to make sure
		 * data portion is linear.
		 */
1606
		if (!pskb_may_pull(skb, skb->len))
L
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1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620
			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;
	}

1621 1622
	++ppp->dev->stats.rx_packets;
	ppp->dev->stats.rx_bytes += skb->len - 2;
L
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1623 1624 1625 1626 1627 1628 1629

	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
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1630
		       && (skb = skb_dequeue(&ppp->file.rq)))
L
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1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641
			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 */
1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662
		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
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1663
#endif /* CONFIG_PPP_FILTER */
1664
			ppp->last_recv = jiffies;
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1665 1666 1667 1668 1669

		if ((ppp->dev->flags & IFF_UP) == 0
		    || ppp->npmode[npi] != NPMODE_PASS) {
			kfree_skb(skb);
		} else {
1670 1671
			/* chop off protocol */
			skb_pull_rcsum(skb, 2);
L
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1672 1673
			skb->dev = ppp->dev;
			skb->protocol = htons(npindex_to_ethertype[npi]);
1674
			skb_reset_mac_header(skb);
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1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698
			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) {
1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710
		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
1711
		if (!ns) {
L
Linus Torvalds 已提交
1712 1713 1714 1715 1716
			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,
1717
				skb->len + 2, ns->data, obuff_size);
L
Linus Torvalds 已提交
1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757
		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;
1758
	struct channel *ch;
L
Linus Torvalds 已提交
1759 1760
	int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;

1761
	if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
L
Linus Torvalds 已提交
1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798
		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);
1799
		++ppp->dev->stats.rx_dropped;
L
Linus Torvalds 已提交
1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811
		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.
	 */
1812
	list_for_each_entry(ch, &ppp->channels, clist) {
L
Linus Torvalds 已提交
1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823
		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. */
1824 1825 1826 1827 1828
	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
1829 1830

	/* Pull completed packets off the queue and receive them. */
J
Joe Perches 已提交
1831
	while ((skb = ppp_mp_reconstruct(ppp)))
L
Linus Torvalds 已提交
1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853
		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. */
1854
	skb_queue_walk(list, p) {
L
Linus Torvalds 已提交
1855 1856
		if (seq_before(seq, p->sequence))
			break;
1857
	}
1858
	__skb_queue_before(list, p, skb);
L
Linus Torvalds 已提交
1859 1860 1861 1862 1863 1864 1865 1866
}

/*
 * 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
1867
static struct sk_buff *
L
Linus Torvalds 已提交
1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 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 1915 1916 1917 1918 1919 1920 1921 1922 1923
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) {
1924
				++ppp->dev->stats.rx_length_errors;
L
Linus Torvalds 已提交
1925 1926 1927 1928 1929 1930 1931 1932
				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) {
1933
				++ppp->dev->stats.rx_missed_errors;
L
Linus Torvalds 已提交
1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961
				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);
1962
			++ppp->dev->stats.rx_dropped;
L
Linus Torvalds 已提交
1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996
			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.
 */

/*
 * Create a new, unattached ppp channel.
 */
int
ppp_register_channel(struct ppp_channel *chan)
{
	struct channel *pch;

1997
	pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
J
Joe Perches 已提交
1998
	if (!pch)
L
Linus Torvalds 已提交
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
		return -ENOMEM;
	pch->ppp = NULL;
	pch->chan = chan;
	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);
	spin_lock_bh(&all_channels_lock);
	pch->file.index = ++last_channel_index;
	list_add(&pch->list, &new_channels);
	atomic_inc(&channel_count);
	spin_unlock_bh(&all_channels_lock);
	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
2026
	if (pch)
L
Linus Torvalds 已提交
2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038
		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
2039
	if (pch) {
L
Linus Torvalds 已提交
2040
		read_lock_bh(&pch->upl);
J
Joe Perches 已提交
2041
		if (pch->ppp)
L
Linus Torvalds 已提交
2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056
			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;

J
Joe Perches 已提交
2057
	if (!pch)
L
Linus Torvalds 已提交
2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088
		return;		/* should never happen */
	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);
	spin_lock_bh(&all_channels_lock);
	list_del(&pch->list);
	spin_unlock_bh(&all_channels_lock);
	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
2089
	if (!pch)
L
Linus Torvalds 已提交
2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117
		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
2118 2119 2120
	cp = try_then_request_module(
		find_compressor(ccp_option[0]),
		"ppp-compress-%d", ccp_option[0]);
J
Joe Perches 已提交
2121
	if (!cp)
L
Linus Torvalds 已提交
2122 2123 2124 2125 2126
		goto out;

	err = -ENOBUFS;
	if (data.transmit) {
		state = cp->comp_alloc(ccp_option, data.length);
J
Joe Perches 已提交
2127
		if (state) {
L
Linus Torvalds 已提交
2128 2129 2130 2131 2132 2133 2134
			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
2135
			if (ostate) {
L
Linus Torvalds 已提交
2136 2137 2138 2139 2140 2141 2142 2143 2144
				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
2145
		if (state) {
L
Linus Torvalds 已提交
2146 2147 2148 2149 2150 2151 2152
			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);
J
Joe Perches 已提交
2153
			if (ostate) {
L
Linus Torvalds 已提交
2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182
				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:

2183
		/* A ConfReq starts negotiation of compression
L
Linus Torvalds 已提交
2184 2185 2186 2187 2188 2189 2190 2191 2192
		 * 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;
2193
		else
L
Linus Torvalds 已提交
2194 2195
			/* I am proposing to what he should send */
			ppp->rstate &= ~SC_DECOMP_RUN;
2196

L
Linus Torvalds 已提交
2197
		break;
2198

L
Linus Torvalds 已提交
2199 2200 2201
	case CCP_TERMREQ:
	case CCP_TERMACK:
		/*
2202
		 * CCP is going down, both directions of transmission
L
Linus Torvalds 已提交
2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
		 */
		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 */
J
Joe Perches 已提交
2220
			if (!ppp->rc_state)
L
Linus Torvalds 已提交
2221 2222 2223 2224 2225 2226 2227 2228
				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 */
J
Joe Perches 已提交
2229
			if (!ppp->xc_state)
L
Linus Torvalds 已提交
2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296
				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;

2297
	list_for_each_entry(ce, &compressor_list, list) {
L
Linus Torvalds 已提交
2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311
		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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Joe Perches 已提交
2312
	if (find_comp_entry(cp->compress_proto))
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2313 2314 2315
		goto out;
	ret = -ENOMEM;
	ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
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Joe Perches 已提交
2316
	if (!ce)
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2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333
		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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Joe Perches 已提交
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	if (ce && ce->comp == cp) {
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		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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	if (ce) {
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		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));
2369 2370 2371 2372 2373 2374
	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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		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 *
ppp_create_interface(int unit, int *retp)
{
	struct ppp *ppp;
	struct net_device *dev = NULL;
	int ret = -ENOMEM;
	int i;

2405
	dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
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	if (!dev)
		goto out1;

2409 2410
	ppp = netdev_priv(dev);
	ppp->dev = dev;
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	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 */

	ret = -EEXIST;
2425
	mutex_lock(&all_ppp_mutex);
2426 2427 2428 2429 2430 2431 2432 2433 2434 2435

	if (unit < 0) {
		unit = unit_get(&ppp_units_idr, ppp);
		if (unit < 0) {
			*retp = unit;
			goto out2;
		}
	} else {
		if (unit_find(&ppp_units_idr, unit))
			goto out2; /* unit already exists */
2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446
		/*
		 * 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 :)
		 */
		unit = unit_set(&ppp_units_idr, ppp, unit);
		if (unit < 0)
2447 2448
			goto out2;
	}
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2449 2450 2451 2452 2453 2454 2455

	/* Initialize the new ppp unit */
	ppp->file.index = unit;
	sprintf(dev->name, "ppp%d", unit);

	ret = register_netdev(dev);
	if (ret != 0) {
2456
		unit_put(&ppp_units_idr, unit);
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		printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
		       dev->name, ret);
		goto out2;
	}

	atomic_inc(&ppp_unit_count);
2463
	mutex_unlock(&all_ppp_mutex);
2464

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	*retp = 0;
	return ppp;

out2:
2469
	mutex_unlock(&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)
{
2495
	mutex_lock(&all_ppp_mutex);
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	/* This will call dev_close() for us. */
2497 2498 2499 2500 2501 2502 2503 2504
	ppp_lock(ppp);
	if (!ppp->closing) {
		ppp->closing = 1;
		ppp_unlock(ppp);
		unregister_netdev(ppp->dev);
	} else
		ppp_unlock(ppp);

2505
	unit_put(&ppp_units_idr, ppp->file.index);
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	ppp->file.dead = 1;
	ppp->owner = NULL;
	wake_up_interruptible(&ppp->file.rwait);
2509
	mutex_unlock(&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
2540 2541 2542 2543
	kfree(ppp->pass_filter);
	ppp->pass_filter = NULL;
	kfree(ppp->active_filter);
	ppp->active_filter = NULL;
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#endif /* CONFIG_PPP_FILTER */

2546 2547 2548
	if (ppp->xmit_pending)
		kfree_skb(ppp->xmit_pending);

2549
	free_netdev(ppp->dev);
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}

/*
 * Locate an existing ppp unit.
2554
 * The caller should have locked the all_ppp_mutex.
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 */
static struct ppp *
ppp_find_unit(int unit)
{
2559
	return unit_find(&ppp_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 *
ppp_find_channel(int unit)
{
	struct channel *pch;

2575
	list_for_each_entry(pch, &new_channels, list) {
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		if (pch->file.index == unit) {
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Akinobu Mita 已提交
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			list_move(&pch->list, &all_channels);
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			return pch;
		}
	}
2581
	list_for_each_entry(pch, &all_channels, list) {
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		if (pch->file.index == unit)
			return pch;
	}
	return NULL;
}

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

2598
	mutex_lock(&all_ppp_mutex);
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	ppp = ppp_find_unit(unit);
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Joe Perches 已提交
2600
	if (!ppp)
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		goto out;
	write_lock_bh(&pch->upl);
	ret = -EINVAL;
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2604
	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 */
2611
	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:
2623
	mutex_unlock(&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);
J
Joe Perches 已提交
2640
	if (ppp) {
L
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2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676
		/* 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");
2677
	unregister_chrdev(PPP_MAJOR, "ppp");
2678
	device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2679
	class_destroy(ppp_class);
2680
	idr_destroy(&ppp_units_idr);
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}

/*
2684 2685
 * Units handling. Caller must protect concurrent access
 * by holding all_ppp_mutex
L
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2686
 */
2687

2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710
/* 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;
}

2711 2712
/* get new free unit number and associate pointer with it */
static int unit_get(struct idr *p, void *ptr)
L
Linus Torvalds 已提交
2713
{
2714
	int unit, err;
L
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2715

2716
again:
2717 2718
	if (!idr_pre_get(p, GFP_KERNEL)) {
		printk(KERN_ERR "PPP: No free memory for idr\n");
2719
		return -ENOMEM;
L
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2720 2721
	}

2722 2723 2724
	err = idr_get_new_above(p, ptr, 0, &unit);
	if (err == -EAGAIN)
		goto again;
L
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2725

2726
	return unit;
L
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2727 2728
}

2729 2730
/* put unit number back to a pool */
static void unit_put(struct idr *p, int n)
L
Linus Torvalds 已提交
2731
{
2732
	idr_remove(p, n);
L
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2733 2734
}

2735 2736
/* get pointer associated with the number */
static void *unit_find(struct idr *p, int n)
L
Linus Torvalds 已提交
2737
{
2738
	return idr_find(p, n);
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2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757
}

/* Module/initialization stuff */

module_init(ppp_init);
module_exit(ppp_cleanup);

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");