/*
* 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>
#include <linux/idr.h>
#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>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/stddef.h>
#include <linux/device.h>
#include <linux/mutex.h>
#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 */
};
#define PF_TO_X(pf, X) container_of(pf, X, file)
#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 */
#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,
* SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
* SC_MUST_COMP
* 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 \
|SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
/*
* 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.
*/
/*
* all_ppp_mutex protects the all_ppp_units mapping.
* It also ensures that finding a ppp unit in the all_ppp_units map
* and updating its file.refcnt field is atomic.
*/
static DEFINE_MUTEX(all_ppp_mutex);
static atomic_t ppp_unit_count = ATOMIC_INIT(0);
static DEFINE_IDR(ppp_units_idr);
/*
* 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);
static int unit_get(struct idr *p, void *ptr);
static void unit_put(struct idr *p, int n);
static void *unit_find(struct idr *p, int n);
static struct class *ppp_class;
/* 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,
};
/* 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)
{
cycle_kernel_lock();
/*
* This could (should?) be enforced by the permissions on /dev/ppp.
*/
if (!capable(CAP_NET_ADMIN))
return -EPERM;
return 0;
}
static int ppp_release(struct inode *unused, struct file *file)
{
struct ppp_file *pf = file->private_data;
struct ppp *ppp;
if (pf) {
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;
if (!pf)
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);
if (!skb)
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;
if (!pf)
return -ENXIO;
ret = -ENOMEM;
skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
if (!skb)
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;
if (!pf)
return 0;
poll_wait(file, &pf->rwait, wait);
mask = POLLOUT | POLLWRNORM;
if (skb_peek(&pf->rq))
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 */
static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
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;
if (!pf)
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;
lock_kernel();
if (pf->kind == INTERFACE) {
ppp = PF_TO_PPP(pf);
if (file == ppp->owner)
ppp_shutdown_interface(ppp);
}
if (atomic_long_read(&file->f_count) <= 2) {
ppp_release(NULL, file);
err = 0;
} else
printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
atomic_long_read(&file->f_count));
unlock_kernel();
return err;
}
if (pf->kind == CHANNEL) {
struct channel *pch;
struct ppp_channel *chan;
lock_kernel();
pch = PF_TO_CHANNEL(pf);
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);
}
unlock_kernel();
return err;
}
if (pf->kind != INTERFACE) {
/* can't happen */
printk(KERN_ERR "PPP: not interface or channel??\n");
return -EINVAL;
}
lock_kernel();
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);
if (!vj) {
printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
err = -ENOMEM;
break;
}
ppp_lock(ppp);
if (ppp->vj)
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;
}
unlock_kernel();
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;
lock_kernel();
switch (cmd) {
case PPPIOCNEWUNIT:
/* Create a new ppp unit */
if (get_user(unit, p))
break;
ppp = ppp_create_interface(unit, &err);
if (!ppp)
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;
mutex_lock(&all_ppp_mutex);
err = -ENXIO;
ppp = ppp_find_unit(unit);
if (ppp) {
atomic_inc(&ppp->file.refcnt);
file->private_data = &ppp->file;
err = 0;
}
mutex_unlock(&all_ppp_mutex);
break;
case PPPIOCATTCHAN:
if (get_user(unit, p))
break;
spin_lock_bh(&all_channels_lock);
err = -ENXIO;
chan = ppp_find_channel(unit);
if (chan) {
atomic_inc(&chan->file.refcnt);
file->private_data = &chan->file;
err = 0;
}
spin_unlock_bh(&all_channels_lock);
break;
default:
err = -ENOTTY;
}
unlock_kernel();
return err;
}
static const struct file_operations ppp_device_fops = {
.owner = THIS_MODULE,
.read = ppp_read,
.write = ppp_write,
.poll = ppp_poll,
.unlocked_ioctl = ppp_ioctl,
.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) {
ppp_class = class_create(THIS_MODULE, "ppp");
if (IS_ERR(ppp_class)) {
err = PTR_ERR(ppp_class);
goto out_chrdev;
}
device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL,
"ppp");
}
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)
{
struct ppp *ppp = netdev_priv(dev);
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. */
if (skb_cow_head(skb, PPP_HDRLEN))
goto outf;
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);
++ppp->dev->stats.tx_dropped;
return 0;
}
static int
ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
struct ppp *ppp = netdev_priv(dev);
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));
if (ppp->xc_state)
ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
if (ppp->rc_state)
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;
}
static const struct net_device_ops ppp_netdev_ops = {
.ndo_start_xmit = ppp_start_xmit,
.ndo_do_ioctl = ppp_net_ioctl,
};
static void ppp_setup(struct net_device *dev)
{
dev->netdev_ops = &ppp_netdev_ops;
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);
if (ppp->dev) {
ppp_push(ppp);
while (!ppp->xmit_pending
&& (skb = skb_dequeue(&ppp->file.xq)))
ppp_send_frame(ppp, skb);
/* If there's no work left to do, tell the core net
code that we can accept some more. */
if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
netif_wake_queue(ppp->dev);
}
ppp_xmit_unlock(ppp);
}
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;
}
/*
* 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 */
}
++ppp->dev->stats.tx_packets;
ppp->dev->stats.tx_bytes += skb->len - 2;
switch (proto) {
case PPP_IP:
if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
break;
/* try to do VJ TCP header compression */
new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
GFP_ATOMIC);
if (!new_skb) {
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 */
if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
&& proto != PPP_LCP && proto != PPP_CCP) {
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");
goto drop;
}
skb = pad_compress_skb(ppp, skb);
if (!skb)
goto drop;
}
/*
* 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:
if (skb)
kfree_skb(skb);
++ppp->dev->stats.tx_errors;
}
/*
* 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;
if (!skb)
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)
{
int len, fragsize;
int i, bits, hdrlen, mtu;
int flen;
int navail, nfree;
int nbigger;
unsigned char *p, *q;
struct list_head *list;
struct channel *pch;
struct sk_buff *frag;
struct ppp_channel *chan;
nfree = 0; /* # channels which have no packet already queued */
navail = 0; /* total # of usable channels (not deregistered) */
hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
i = 0;
list_for_each_entry(pch, &ppp->channels, clist) {
navail += pch->avail = (pch->chan != NULL);
if (pch->avail) {
if (skb_queue_empty(&pch->file.xq) ||
!pch->had_frag) {
pch->avail = 2;
++nfree;
}
if (!pch->had_frag && i < ppp->nxchan)
ppp->nxchan = i;
}
++i;
}
/*
* 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)
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;
}
/*
* 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.
*/
fragsize = len;
if (nfree > 1)
fragsize = DIV_ROUND_UP(fragsize, nfree);
/* nbigger channels get fragsize bytes, the rest get fragsize-1,
except if nbigger==0, then they all get fragsize. */
nbigger = len % nfree;
/* skip to the channel after the one we last used
and start at that one */
list = &ppp->channels;
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;
while (nfree > 0 || len > 0) {
list = list->next;
if (list == &ppp->channels) {
i = 0;
continue;
}
pch = list_entry(list, struct channel, clist);
++i;
if (!pch->avail)
continue;
/*
* 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;
}
/* check the channel's mtu and whether it is still attached. */
spin_lock_bh(&pch->downl);
if (pch->chan == NULL) {
/* can't use this channel, it's being deregistered */
spin_unlock_bh(&pch->downl);
pch->avail = 0;
if (--navail == 0)
break;
continue;
}
/*
* 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.
*/
if (fragsize > len)
fragsize = len;
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);
if (!frag)
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;
}
/*
* 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;
if (!skb_queue_empty(&pch->file.xq) ||
!chan->ops->start_xmit(chan, frag))
skb_queue_tail(&pch->file.xq, frag);
pch->had_frag = 1;
p += flen;
len -= flen;
++ppp->nxseq;
bits = 0;
spin_unlock_bh(&pch->downl);
if (--nbigger == 0 && fragsize > 0)
--fragsize;
}
ppp->nxchan = i;
return 1;
noskb:
spin_unlock_bh(&pch->downl);
if (ppp->debug & 1)
printk(KERN_ERR "PPP: no memory (fragment)\n");
++ppp->dev->stats.tx_errors;
++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);
if (pch->chan) {
while (!skb_queue_empty(&pch->file.xq)) {
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 */
if (skb_queue_empty(&pch->file.xq)) {
read_lock_bh(&pch->upl);
ppp = pch->ppp;
if (ppp)
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);
/* ppp->dev == 0 means interface is closing down */
if (ppp->dev)
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;
if (!pch || skb->len == 0) {
kfree_skb(skb);
return;
}
proto = PPP_PROTO(skb);
read_lock_bh(&pch->upl);
if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
/* 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
&& (skb = skb_dequeue(&pch->file.rq)))
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;
if (!pch)
return;
read_lock_bh(&pch->upl);
if (pch->ppp) {
skb = alloc_skb(0, GFP_ATOMIC);
if (skb) {
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)
{
if (pskb_may_pull(skb, 2)) {
#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 */
++ppp->dev->stats.rx_length_errors;
kfree_skb(skb);
ppp_receive_error(ppp);
}
static void
ppp_receive_error(struct ppp *ppp)
{
++ppp->dev->stats.rx_errors;
if (ppp->vj)
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.
*/
if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
&& (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
skb = ppp_decompress_frame(ppp, skb);
if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
goto err;
proto = PPP_PROTO(skb);
switch (proto) {
case PPP_VJC_COMP:
/* decompress VJ compressed packets */
if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
goto err;
if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
/* copy to a new sk_buff with more tailroom */
ns = dev_alloc_skb(skb->len + 128);
if (!ns) {
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;
}
else
skb->ip_summed = CHECKSUM_NONE;
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:
if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
goto err;
/* Until we fix the decompressor need to make sure
* data portion is linear.
*/
if (!pskb_may_pull(skb, skb->len))
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;
}
++ppp->dev->stats.rx_packets;
ppp->dev->stats.rx_bytes += skb->len - 2;
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
&& (skb = skb_dequeue(&ppp->file.rq)))
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 */
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
#endif /* CONFIG_PPP_FILTER */
ppp->last_recv = jiffies;
if ((ppp->dev->flags & IFF_UP) == 0
|| ppp->npmode[npi] != NPMODE_PASS) {
kfree_skb(skb);
} else {
/* chop off protocol */
skb_pull_rcsum(skb, 2);
skb->dev = ppp->dev;
skb->protocol = htons(npindex_to_ethertype[npi]);
skb_reset_mac_header(skb);
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) {
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);
if (!ns) {
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,
skb->len + 2, ns->data, obuff_size);
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;
struct channel *ch;
int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
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);
++ppp->dev->stats.rx_dropped;
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.
*/
list_for_each_entry(ch, &ppp->channels, clist) {
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. */
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;
}
/* Pull completed packets off the queue and receive them. */
while ((skb = ppp_mp_reconstruct(ppp)))
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. */
skb_queue_walk(list, p) {
if (seq_before(seq, p->sequence))
break;
}
__skb_queue_before(list, p, skb);
}
/*
* 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.
*/
static struct sk_buff *
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) {
++ppp->dev->stats.rx_length_errors;
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) {
++ppp->dev->stats.rx_missed_errors;
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);
++ppp->dev->stats.rx_dropped;
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;
pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
if (!pch)
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;
if (pch)
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;
if (pch) {
read_lock_bh(&pch->upl);
if (pch->ppp)
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;
if (!pch)
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;
if (!pch)
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;
cp = try_then_request_module(
find_compressor(ccp_option[0]),
"ppp-compress-%d", ccp_option[0]);
if (!cp)
goto out;
err = -ENOBUFS;
if (data.transmit) {
state = cp->comp_alloc(ccp_option, data.length);
if (state) {
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);
if (ostate) {
ocomp->comp_free(ostate);
module_put(ocomp->owner);
}
err = 0;
} else
module_put(cp->owner);
} else {
state = cp->decomp_alloc(ccp_option, data.length);
if (state) {
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);
if (ostate) {
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:
/* A ConfReq starts negotiation of compression
* 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;
else
/* I am proposing to what he should send */
ppp->rstate &= ~SC_DECOMP_RUN;
break;
case CCP_TERMREQ:
case CCP_TERMACK:
/*
* CCP is going down, both directions of transmission
*/
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 */
if (!ppp->rc_state)
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 */
if (!ppp->xc_state)
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;
list_for_each_entry(ce, &compressor_list, list) {
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;
if (find_comp_entry(cp->compress_proto))
goto out;
ret = -ENOMEM;
ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
if (!ce)
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);
if (ce && ce->comp == cp) {
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);
if (ce) {
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));
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;
if (!vj)
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;
dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
if (!dev)
goto out1;
ppp = netdev_priv(dev);
ppp->dev = dev;
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;
mutex_lock(&all_ppp_mutex);
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 */
else {
/* darn, someone is cheating us? */
*retp = -EINVAL;
goto out2;
}
}
/* Initialize the new ppp unit */
ppp->file.index = unit;
sprintf(dev->name, "ppp%d", unit);
ret = register_netdev(dev);
if (ret != 0) {
unit_put(&ppp_units_idr, unit);
printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
dev->name, ret);
goto out2;
}
atomic_inc(&ppp_unit_count);
mutex_unlock(&all_ppp_mutex);
*retp = 0;
return ppp;
out2:
mutex_unlock(&all_ppp_mutex);
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)
{
struct net_device *dev;
mutex_lock(&all_ppp_mutex);
ppp_lock(ppp);
dev = ppp->dev;
ppp->dev = NULL;
ppp_unlock(ppp);
/* This will call dev_close() for us. */
if (dev) {
unregister_netdev(dev);
free_netdev(dev);
}
unit_put(&ppp_units_idr, ppp->file.index);
ppp->file.dead = 1;
ppp->owner = NULL;
wake_up_interruptible(&ppp->file.rwait);
mutex_unlock(&all_ppp_mutex);
}
/*
* 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
kfree(ppp->pass_filter);
ppp->pass_filter = NULL;
kfree(ppp->active_filter);
ppp->active_filter = NULL;
#endif /* CONFIG_PPP_FILTER */
if (ppp->xmit_pending)
kfree_skb(ppp->xmit_pending);
kfree(ppp);
}
/*
* Locate an existing ppp unit.
* The caller should have locked the all_ppp_mutex.
*/
static struct ppp *
ppp_find_unit(int unit)
{
return unit_find(&ppp_units_idr, unit);
}
/*
* 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;
list_for_each_entry(pch, &new_channels, list) {
if (pch->file.index == unit) {
list_move(&pch->list, &all_channels);
return pch;
}
}
list_for_each_entry(pch, &all_channels, list) {
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;
mutex_lock(&all_ppp_mutex);
ppp = ppp_find_unit(unit);
if (!ppp)
goto out;
write_lock_bh(&pch->upl);
ret = -EINVAL;
if (pch->ppp)
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 */
if (ppp->dev && hdrlen > ppp->dev->hard_header_len)
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:
mutex_unlock(&all_ppp_mutex);
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);
if (ppp) {
/* 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");
unregister_chrdev(PPP_MAJOR, "ppp");
device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
class_destroy(ppp_class);
idr_destroy(&ppp_units_idr);
}
/*
* Units handling. Caller must protect concurrent access
* by holding all_ppp_mutex
*/
/* get new free unit number and associate pointer with it */
static int unit_get(struct idr *p, void *ptr)
{
int unit, err;
again:
if (idr_pre_get(p, GFP_KERNEL) == 0) {
printk(KERN_ERR "Out of memory expanding drawable idr\n");
return -ENOMEM;
}
err = idr_get_new_above(p, ptr, 0, &unit);
if (err == -EAGAIN)
goto again;
return unit;
}
/* put unit number back to a pool */
static void unit_put(struct idr *p, int n)
{
idr_remove(p, n);
}
/* get pointer associated with the number */
static void *unit_find(struct idr *p, int n)
{
return idr_find(p, n);
}
/* 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");
