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linux/drivers/net/ppp/ppp_generic.c
David S. Miller 8b69bd7d8a ppp: Remove direct skb_queue_head list pointer access. 
Add a helper, __skb_peek(), and use it in ppp_mp_reconstruct().

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-10 10:06:53 -07:00

3289 lines
76 KiB
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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/sched/signal.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/ppp-ioctl.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/spinlock.h>
#include <linux/rwsem.h>
#include <linux/stddef.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <asm/unaligned.h>
#include <net/slhc_vj.h>
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <net/netns/generic.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 */
/*
* 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 */
refcount_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 to hold primary network stats for which
* we want to use 64 bit storage. Other network stats
* are stored in dev->stats of the ppp strucute.
*/
struct ppp_link_stats {
u64 rx_packets;
u64 tx_packets;
u64 rx_bytes;
u64 tx_bytes;
};
/*
* 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 __percpu *xmit_recursion; /* xmit recursion detect */
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 */
int closing; /* is device closing down? a8 */
#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 bpf_prog *pass_filter; /* filter for packets to pass */
struct bpf_prog *active_filter; /* filter for pkts to reset idle */
#endif /* CONFIG_PPP_FILTER */
struct net *ppp_net; /* the net we belong to */
struct ppp_link_stats stats64; /* 64 bit network stats */
};
/*
* 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 net *chan_net; /* the net channel belongs 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 */
int speed; /* speed of the corresponding ppp channel*/
#endif /* CONFIG_PPP_MULTILINK */
};
struct ppp_config {
struct file *file;
s32 unit;
bool ifname_is_set;
};
/*
* SMP locking issues:
* Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
* list and the ppp.n_channels field, you need to take both locks
* before you modify them.
* The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
* channel.downl.
*/
static DEFINE_MUTEX(ppp_mutex);
static atomic_t ppp_unit_count = ATOMIC_INIT(0);
static atomic_t channel_count = ATOMIC_INIT(0);
/* per-net private data for this module */
static unsigned int ppp_net_id __read_mostly;
struct ppp_net {
/* units to ppp mapping */
struct idr units_idr;
/*
* all_ppp_mutex protects the units_idr mapping.
* It also ensures that finding a ppp unit in the units_idr
* map and updating its file.refcnt field is atomic.
*/
struct mutex all_ppp_mutex;
/* channels */
struct list_head all_channels;
struct list_head new_channels;
int last_channel_index;
/*
* all_channels_lock protects all_channels and
* last_channel_index, and the atomicity of find
* a channel and updating its file.refcnt field.
*/
spinlock_t all_channels_lock;
};
/* Get the PPP protocol number from a skb */
#define PPP_PROTO(skb) get_unaligned_be16((skb)->data)
/* 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 net *net, struct ppp_file *pf,
struct file *file, unsigned int cmd, unsigned long arg);
static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
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 int ppp_create_interface(struct net *net, struct file *file, int *unit);
static void init_ppp_file(struct ppp_file *pf, int kind);
static void ppp_destroy_interface(struct ppp *ppp);
static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
static struct channel *ppp_find_channel(struct ppp_net *pn, 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 int unit_set(struct idr *p, void *ptr, int n);
static void unit_put(struct idr *p, int n);
static void *unit_find(struct idr *p, int n);
static void ppp_setup(struct net_device *dev);
static const struct net_device_ops ppp_netdev_ops;
static struct class *ppp_class;
/* per net-namespace data */
static inline struct ppp_net *ppp_pernet(struct net *net)
{
BUG_ON(!net);
return net_generic(net, ppp_net_id);
}
/* 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)
{
/*
* This could (should?) be enforced by the permissions on /dev/ppp.
*/
if (!ns_capable(file->f_cred->user_ns, 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);
rtnl_lock();
if (file == ppp->owner)
unregister_netdevice(ppp->dev);
rtnl_unlock();
}
if (refcount_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;
struct iovec iov;
struct iov_iter to;
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);
ppp_recv_lock(ppp);
if (ppp->n_channels == 0 &&
(ppp->flags & SC_LOOP_TRAFFIC) == 0) {
ppp_recv_unlock(ppp);
break;
}
ppp_recv_unlock(ppp);
}
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;
iov.iov_base = buf;
iov.iov_len = count;
iov_iter_init(&to, READ, &iov, 1, count);
if (skb_copy_datagram_iter(skb, 0, &to, 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;
}
switch (pf->kind) {
case INTERFACE:
ppp_xmit_process(PF_TO_PPP(pf), skb);
break;
case CHANNEL:
skb_queue_tail(&pf->xq, skb);
ppp_channel_push(PF_TO_CHANNEL(pf));
break;
}
ret = count;
out:
return ret;
}
/* No kernel lock - fine */
static __poll_t ppp_poll(struct file *file, poll_table *wait)
{
struct ppp_file *pf = file->private_data;
__poll_t mask;
if (!pf)
return 0;
poll_wait(file, &pf->rwait, wait);
mask = EPOLLOUT | EPOLLWRNORM;
if (skb_peek(&pf->rq))
mask |= EPOLLIN | EPOLLRDNORM;
if (pf->dead)
mask |= EPOLLHUP;
else if (pf->kind == INTERFACE) {
/* see comment in ppp_read */
struct ppp *ppp = PF_TO_PPP(pf);
ppp_recv_lock(ppp);
if (ppp->n_channels == 0 &&
(ppp->flags & SC_LOOP_TRAFFIC) == 0)
mask |= EPOLLIN | EPOLLRDNORM;
ppp_recv_unlock(ppp);
}
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;
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 = memdup_user(uprog.filter, len);
if (IS_ERR(code))
return PTR_ERR(code);
*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;
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;
mutex_lock(&ppp_mutex);
pf = file->private_data;
if (!pf) {
err = ppp_unattached_ioctl(current->nsproxy->net_ns,
pf, file, cmd, arg);
goto out;
}
if (cmd == PPPIOCDETACH) {
/*
* PPPIOCDETACH is no longer supported as it was heavily broken,
* and is only known to have been used by pppd older than
* ppp-2.4.2 (released November 2003).
*/
pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
current->comm, current->pid);
err = -EINVAL;
goto out;
}
if (pf->kind == CHANNEL) {
struct channel *pch;
struct ppp_channel *chan;
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);
}
goto out;
}
if (pf->kind != INTERFACE) {
/* can't happen */
pr_err("PPP: not interface or channel??\n");
err = -EINVAL;
goto out;
}
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;
#ifdef CONFIG_PPP_MULTILINK
if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
ppp->nextseq = 0;
#endif
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 (IS_ERR(vj)) {
err = PTR_ERR(vj);
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) {
struct bpf_prog *pass_filter = NULL;
struct sock_fprog_kern fprog = {
.len = err,
.filter = code,
};
err = 0;
if (fprog.filter)
err = bpf_prog_create(&pass_filter, &fprog);
if (!err) {
ppp_lock(ppp);
if (ppp->pass_filter)
bpf_prog_destroy(ppp->pass_filter);
ppp->pass_filter = pass_filter;
ppp_unlock(ppp);
}
kfree(code);
}
break;
}
case PPPIOCSACTIVE:
{
struct sock_filter *code;
err = get_filter(argp, &code);
if (err >= 0) {
struct bpf_prog *active_filter = NULL;
struct sock_fprog_kern fprog = {
.len = err,
.filter = code,
};
err = 0;
if (fprog.filter)
err = bpf_prog_create(&active_filter, &fprog);
if (!err) {
ppp_lock(ppp);
if (ppp->active_filter)
bpf_prog_destroy(ppp->active_filter);
ppp->active_filter = active_filter;
ppp_unlock(ppp);
}
kfree(code);
}
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;
}
out:
mutex_unlock(&ppp_mutex);
return err;
}
static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
struct file *file, unsigned int cmd, unsigned long arg)
{
int unit, err = -EFAULT;
struct ppp *ppp;
struct channel *chan;
struct ppp_net *pn;
int __user *p = (int __user *)arg;
switch (cmd) {
case PPPIOCNEWUNIT:
/* Create a new ppp unit */
if (get_user(unit, p))
break;
err = ppp_create_interface(net, file, &unit);
if (err < 0)
break;
err = -EFAULT;
if (put_user(unit, p))
break;
err = 0;
break;
case PPPIOCATTACH:
/* Attach to an existing ppp unit */
if (get_user(unit, p))
break;
err = -ENXIO;
pn = ppp_pernet(net);
mutex_lock(&pn->all_ppp_mutex);
ppp = ppp_find_unit(pn, unit);
if (ppp) {
refcount_inc(&ppp->file.refcnt);
file->private_data = &ppp->file;
err = 0;
}
mutex_unlock(&pn->all_ppp_mutex);
break;
case PPPIOCATTCHAN:
if (get_user(unit, p))
break;
err = -ENXIO;
pn = ppp_pernet(net);
spin_lock_bh(&pn->all_channels_lock);
chan = ppp_find_channel(pn, unit);
if (chan) {
refcount_inc(&chan->file.refcnt);
file->private_data = &chan->file;
err = 0;
}
spin_unlock_bh(&pn->all_channels_lock);
break;
default:
err = -ENOTTY;
}
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,
.llseek = noop_llseek,
};
static __net_init int ppp_init_net(struct net *net)
{
struct ppp_net *pn = net_generic(net, ppp_net_id);
idr_init(&pn->units_idr);
mutex_init(&pn->all_ppp_mutex);
INIT_LIST_HEAD(&pn->all_channels);
INIT_LIST_HEAD(&pn->new_channels);
spin_lock_init(&pn->all_channels_lock);
return 0;
}
static __net_exit void ppp_exit_net(struct net *net)
{
struct ppp_net *pn = net_generic(net, ppp_net_id);
struct net_device *dev;
struct net_device *aux;
struct ppp *ppp;
LIST_HEAD(list);
int id;
rtnl_lock();
for_each_netdev_safe(net, dev, aux) {
if (dev->netdev_ops == &ppp_netdev_ops)
unregister_netdevice_queue(dev, &list);
}
idr_for_each_entry(&pn->units_idr, ppp, id)
/* Skip devices already unregistered by previous loop */
if (!net_eq(dev_net(ppp->dev), net))
unregister_netdevice_queue(ppp->dev, &list);
unregister_netdevice_many(&list);
rtnl_unlock();
mutex_destroy(&pn->all_ppp_mutex);
idr_destroy(&pn->units_idr);
WARN_ON_ONCE(!list_empty(&pn->all_channels));
WARN_ON_ONCE(!list_empty(&pn->new_channels));
}
static struct pernet_operations ppp_net_ops = {
.init = ppp_init_net,
.exit = ppp_exit_net,
.id = &ppp_net_id,
.size = sizeof(struct ppp_net),
};
static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
{
struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
int ret;
mutex_lock(&pn->all_ppp_mutex);
if (unit < 0) {
ret = unit_get(&pn->units_idr, ppp);
if (ret < 0)
goto err;
} else {
/* Caller asked for a specific unit number. Fail with -EEXIST
* if unavailable. For backward compatibility, return -EEXIST
* too if idr allocation fails; this makes pppd retry without
* requesting a specific unit number.
*/
if (unit_find(&pn->units_idr, unit)) {
ret = -EEXIST;
goto err;
}
ret = unit_set(&pn->units_idr, ppp, unit);
if (ret < 0) {
/* Rewrite error for backward compatibility */
ret = -EEXIST;
goto err;
}
}
ppp->file.index = ret;
if (!ifname_is_set)
snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
mutex_unlock(&pn->all_ppp_mutex);
ret = register_netdevice(ppp->dev);
if (ret < 0)
goto err_unit;
atomic_inc(&ppp_unit_count);
return 0;
err_unit:
mutex_lock(&pn->all_ppp_mutex);
unit_put(&pn->units_idr, ppp->file.index);
err:
mutex_unlock(&pn->all_ppp_mutex);
return ret;
}
static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
const struct ppp_config *conf)
{
struct ppp *ppp = netdev_priv(dev);
int indx;
int err;
int cpu;
ppp->dev = dev;
ppp->ppp_net = src_net;
ppp->mru = PPP_MRU;
ppp->owner = conf->file;
init_ppp_file(&ppp->file, INTERFACE);
ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
for (indx = 0; indx < NUM_NP; ++indx)
ppp->npmode[indx] = NPMODE_PASS;
INIT_LIST_HEAD(&ppp->channels);
spin_lock_init(&ppp->rlock);
spin_lock_init(&ppp->wlock);
ppp->xmit_recursion = alloc_percpu(int);
if (!ppp->xmit_recursion) {
err = -ENOMEM;
goto err1;
}
for_each_possible_cpu(cpu)
(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
#ifdef CONFIG_PPP_MULTILINK
ppp->minseq = -1;
skb_queue_head_init(&ppp->mrq);
#endif /* CONFIG_PPP_MULTILINK */
#ifdef CONFIG_PPP_FILTER
ppp->pass_filter = NULL;
ppp->active_filter = NULL;
#endif /* CONFIG_PPP_FILTER */
err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
if (err < 0)
goto err2;
conf->file->private_data = &ppp->file;
return 0;
err2:
free_percpu(ppp->xmit_recursion);
err1:
return err;
}
static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
[IFLA_PPP_DEV_FD] = { .type = NLA_S32 },
};
static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
if (!data)
return -EINVAL;
if (!data[IFLA_PPP_DEV_FD])
return -EINVAL;
if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
return -EBADF;
return 0;
}
static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
struct ppp_config conf = {
.unit = -1,
.ifname_is_set = true,
};
struct file *file;
int err;
file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
if (!file)
return -EBADF;
/* rtnl_lock is already held here, but ppp_create_interface() locks
* ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
* possible deadlock due to lock order inversion, at the cost of
* pushing the problem back to userspace.
*/
if (!mutex_trylock(&ppp_mutex)) {
err = -EBUSY;
goto out;
}
if (file->f_op != &ppp_device_fops || file->private_data) {
err = -EBADF;
goto out_unlock;
}
conf.file = file;
/* Don't use device name generated by the rtnetlink layer when ifname
* isn't specified. Let ppp_dev_configure() set the device name using
* the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
* userspace to infer the device name using to the PPPIOCGUNIT ioctl.
*/
if (!tb[IFLA_IFNAME])
conf.ifname_is_set = false;
err = ppp_dev_configure(src_net, dev, &conf);
out_unlock:
mutex_unlock(&ppp_mutex);
out:
fput(file);
return err;
}
static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
{
unregister_netdevice_queue(dev, head);
}
static size_t ppp_nl_get_size(const struct net_device *dev)
{
return 0;
}
static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
return 0;
}
static struct net *ppp_nl_get_link_net(const struct net_device *dev)
{
struct ppp *ppp = netdev_priv(dev);
return ppp->ppp_net;
}
static struct rtnl_link_ops ppp_link_ops __read_mostly = {
.kind = "ppp",
.maxtype = IFLA_PPP_MAX,
.policy = ppp_nl_policy,
.priv_size = sizeof(struct ppp),
.setup = ppp_setup,
.validate = ppp_nl_validate,
.newlink = ppp_nl_newlink,
.dellink = ppp_nl_dellink,
.get_size = ppp_nl_get_size,
.fill_info = ppp_nl_fill_info,
.get_link_net = ppp_nl_get_link_net,
};
#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;
pr_info("PPP generic driver version " PPP_VERSION "\n");
err = register_pernet_device(&ppp_net_ops);
if (err) {
pr_err("failed to register PPP pernet device (%d)\n", err);
goto out;
}
err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
if (err) {
pr_err("failed to register PPP device (%d)\n", err);
goto out_net;
}
ppp_class = class_create(THIS_MODULE, "ppp");
if (IS_ERR(ppp_class)) {
err = PTR_ERR(ppp_class);
goto out_chrdev;
}
err = rtnl_link_register(&ppp_link_ops);
if (err) {
pr_err("failed to register rtnetlink PPP handler\n");
goto out_class;
}
/* not a big deal if we fail here :-) */
device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
return 0;
out_class:
class_destroy(ppp_class);
out_chrdev:
unregister_chrdev(PPP_MAJOR, "ppp");
out_net:
unregister_pernet_device(&ppp_net_ops);
out:
return err;
}
/*
* Network interface unit routines.
*/
static netdev_tx_t
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];
put_unaligned_be16(proto, pp);
skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
ppp_xmit_process(ppp, skb);
return NETDEV_TX_OK;
outf:
kfree_skb(skb);
++dev->stats.tx_dropped;
return NETDEV_TX_OK;
}
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 void
ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
{
struct ppp *ppp = netdev_priv(dev);
ppp_recv_lock(ppp);
stats64->rx_packets = ppp->stats64.rx_packets;
stats64->rx_bytes = ppp->stats64.rx_bytes;
ppp_recv_unlock(ppp);
ppp_xmit_lock(ppp);
stats64->tx_packets = ppp->stats64.tx_packets;
stats64->tx_bytes = ppp->stats64.tx_bytes;
ppp_xmit_unlock(ppp);
stats64->rx_errors = dev->stats.rx_errors;
stats64->tx_errors = dev->stats.tx_errors;
stats64->rx_dropped = dev->stats.rx_dropped;
stats64->tx_dropped = dev->stats.tx_dropped;
stats64->rx_length_errors = dev->stats.rx_length_errors;
}
static int ppp_dev_init(struct net_device *dev)
{
struct ppp *ppp;
netdev_lockdep_set_classes(dev);
ppp = netdev_priv(dev);
/* Let the netdevice take a reference on the ppp file. This ensures
* that ppp_destroy_interface() won't run before the device gets
* unregistered.
*/
refcount_inc(&ppp->file.refcnt);
return 0;
}
static void ppp_dev_uninit(struct net_device *dev)
{
struct ppp *ppp = netdev_priv(dev);
struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
ppp_lock(ppp);
ppp->closing = 1;
ppp_unlock(ppp);
mutex_lock(&pn->all_ppp_mutex);
unit_put(&pn->units_idr, ppp->file.index);
mutex_unlock(&pn->all_ppp_mutex);
ppp->owner = NULL;
ppp->file.dead = 1;
wake_up_interruptible(&ppp->file.rwait);
}
static void ppp_dev_priv_destructor(struct net_device *dev)
{
struct ppp *ppp;
ppp = netdev_priv(dev);
if (refcount_dec_and_test(&ppp->file.refcnt))
ppp_destroy_interface(ppp);
}
static const struct net_device_ops ppp_netdev_ops = {
.ndo_init = ppp_dev_init,
.ndo_uninit = ppp_dev_uninit,
.ndo_start_xmit = ppp_start_xmit,
.ndo_do_ioctl = ppp_net_ioctl,
.ndo_get_stats64 = ppp_get_stats64,
};
static struct device_type ppp_type = {
.name = "ppp",
};
static void ppp_setup(struct net_device *dev)
{
dev->netdev_ops = &ppp_netdev_ops;
SET_NETDEV_DEVTYPE(dev, &ppp_type);
dev->features |= NETIF_F_LLTX;
dev->hard_header_len = PPP_HDRLEN;
dev->mtu = PPP_MRU;
dev->addr_len = 0;
dev->tx_queue_len = 3;
dev->type = ARPHRD_PPP;
dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
dev->priv_destructor = ppp_dev_priv_destructor;
netif_keep_dst(dev);
}
/*
* 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->closing) {
ppp_push(ppp);
if (skb)
skb_queue_tail(&ppp->file.xq, skb);
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);
else
netif_stop_queue(ppp->dev);
}
ppp_xmit_unlock(ppp);
}
static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
{
local_bh_disable();
if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
goto err;
(*this_cpu_ptr(ppp->xmit_recursion))++;
__ppp_xmit_process(ppp, skb);
(*this_cpu_ptr(ppp->xmit_recursion))--;
local_bh_enable();
return;
err:
local_bh_enable();
kfree_skb(skb);
if (net_ratelimit())
netdev_err(ppp->dev, "recursion detected\n");
}
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())
netdev_err(ppp->dev, "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)) {
consume_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 */
consume_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())
netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
kfree_skb(skb);
consume_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 */
*(u8 *)skb_push(skb, 2) = 1;
if (ppp->pass_filter &&
BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
if (ppp->debug & 1)
netdev_printk(KERN_DEBUG, ppp->dev,
"PPP: outbound frame "
"not passed\n");
kfree_skb(skb);
return;
}
/* if this packet passes the active filter, record the time */
if (!(ppp->active_filter &&
BPF_PROG_RUN(ppp->active_filter, skb) == 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->stats64.tx_packets;
ppp->stats64.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) {
netdev_err(ppp->dev, "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 */
consume_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];
}
consume_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())
netdev_err(ppp->dev,
"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:
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(&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(&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
static bool mp_protocol_compress __read_mostly = true;
module_param(mp_protocol_compress, bool, 0644);
MODULE_PARM_DESC(mp_protocol_compress,
"compress protocol id in multilink fragments");
/*
* 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, totlen;
int i, bits, hdrlen, mtu;
int flen;
int navail, nfree, nzero;
int nbigger;
int totspeed;
int totfree;
unsigned char *p, *q;
struct list_head *list;
struct channel *pch;
struct sk_buff *frag;
struct ppp_channel *chan;
totspeed = 0; /*total bitrate of the bundle*/
nfree = 0; /* # channels which have no packet already queued */
navail = 0; /* total # of usable channels (not deregistered) */
nzero = 0; /* number of channels with zero speed associated*/
totfree = 0; /*total # of channels available and
*having no queued packets before
*starting the fragmentation*/
hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
i = 0;
list_for_each_entry(pch, &ppp->channels, clist) {
if (pch->chan) {
pch->avail = 1;
navail++;
pch->speed = pch->chan->speed;
} else {
pch->avail = 0;
}
if (pch->avail) {
if (skb_queue_empty(&pch->file.xq) ||
!pch->had_frag) {
if (pch->speed == 0)
nzero++;
else
totspeed += pch->speed;
pch->avail = 2;
++nfree;
++totfree;
}
if (!pch->had_frag && i < ppp->nxchan)
ppp->nxchan = i;
}
++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 */
p = skb->data;
len = skb->len;
if (*p == 0 && mp_protocol_compress) {
++p;
--len;
}
totlen = len;
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 (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 {
pch->avail = 1;
}
/* check the channel's mtu and whether it is still attached. */
spin_lock(&pch->downl);
if (pch->chan == NULL) {
/* can't use this channel, it's being deregistered */
if (pch->speed == 0)
nzero--;
else
totspeed -= pch->speed;
spin_unlock(&pch->downl);
pch->avail = 0;
totlen = len;
totfree--;
nfree--;
if (--navail == 0)
break;
continue;
}
/*
*if the channel speed is not set divide
*the packet evenly among the free channels;
*otherwise divide it according to the speed
*of the channel we are going to transmit on
*/
flen = len;
if (nfree > 0) {
if (pch->speed == 0) {
flen = len/nfree;
if (nbigger > 0) {
flen++;
nbigger--;
}
} else {
flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
((totspeed*totfree)/pch->speed)) - hdrlen;
if (nbigger > 0) {
flen += ((totfree - nzero)*pch->speed)/totspeed;
nbigger -= ((totfree - nzero)*pch->speed)/
totspeed;
}
}
nfree--;
}
/*
*check if we are on the last channel or
*we exceded the length of the data to
*fragment
*/
if ((nfree <= 0) || (flen > len))
flen = len;
/*
*it is not worth to tx on slow channels:
*in that case from the resulting flen according to the
*above formula will be equal or less than zero.
*Skip the channel in this case
*/
if (flen <= 0) {
pch->avail = 2;
spin_unlock(&pch->downl);
continue;
}
/*
* hdrlen includes the 2-byte PPP protocol field, but the
* MTU counts only the payload excluding the protocol field.
* (RFC1661 Section 2)
*/
mtu = pch->chan->mtu - (hdrlen - 2);
if (mtu < 4)
mtu = 4;
if (flen > mtu)
flen = mtu;
if (flen == len)
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 */
put_unaligned_be16(PPP_MP, q);
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;
}
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(&pch->downl);
}
ppp->nxchan = i;
return 1;
noskb:
spin_unlock(&pch->downl);
if (ppp->debug & 1)
netdev_err(ppp->dev, "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(&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(&pch->downl);
/* see if there is anything from the attached unit to be sent */
if (skb_queue_empty(&pch->file.xq)) {
ppp = pch->ppp;
if (ppp)
__ppp_xmit_process(ppp, NULL);
}
}
static void ppp_channel_push(struct channel *pch)
{
read_lock_bh(&pch->upl);
if (pch->ppp) {
(*this_cpu_ptr(pch->ppp->xmit_recursion))++;
__ppp_channel_push(pch);
(*this_cpu_ptr(pch->ppp->xmit_recursion))--;
} else {
__ppp_channel_push(pch);
}
read_unlock_bh(&pch->upl);
}
/*
* Receive-side routines.
*/
struct ppp_mp_skb_parm {
u32 sequence;
u8 BEbits;
};
#define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb))
static inline void
ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
{
ppp_recv_lock(ppp);
if (!ppp->closing)
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) {
kfree_skb(skb);
return;
}
read_lock_bh(&pch->upl);
if (!pskb_may_pull(skb, 2)) {
kfree_skb(skb);
if (pch->ppp) {
++pch->ppp->dev->stats.rx_length_errors;
ppp_receive_error(pch->ppp);
}
goto done;
}
proto = PPP_PROTO(skb);
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);
}
done:
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)
{
/* note: a 0-length skb is used as an error indication */
if (skb->len > 0) {
skb_checksum_complete_unset(skb);
#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);
} else {
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) {
netdev_err(ppp->dev, "PPP: no memory "
"(VJ decomp)\n");
goto err;
}
skb_reserve(ns, 2);
skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
consume_skb(skb);
skb = ns;
}
else
skb->ip_summed = CHECKSUM_NONE;
len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
if (len <= 0) {
netdev_printk(KERN_DEBUG, ppp->dev,
"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) {
netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
goto err;
}
proto = PPP_IP;
break;
case PPP_CCP:
ppp_ccp_peek(ppp, skb, 1);
break;
}
++ppp->stats64.rx_packets;
ppp->stats64.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_unclone(skb, GFP_ATOMIC))
goto err;
*(u8 *)skb_push(skb, 2) = 0;
if (ppp->pass_filter &&
BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
if (ppp->debug & 1)
netdev_printk(KERN_DEBUG, ppp->dev,
"PPP: inbound frame "
"not passed\n");
kfree_skb(skb);
return;
}
if (!(ppp->active_filter &&
BPF_PROG_RUN(ppp->active_filter, skb) == 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);
skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
dev_net(ppp->dev)));
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) {
netdev_err(ppp->dev, "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;
}
consume_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;
}
PPP_MP_CB(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 ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
*(u8 *)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 */
PPP_MP_CB(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 *mskb = skb_peek(&ppp->mrq);
if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
ppp->minseq = PPP_MP_CB(mskb)->sequence;
}
/* Pull completed packets off the queue and receive them. */
while ((skb = ppp_mp_reconstruct(ppp))) {
if (pskb_may_pull(skb, 2))
ppp_receive_nonmp_frame(ppp, skb);
else {
++ppp->dev->stats.rx_length_errors;
kfree_skb(skb);
ppp_receive_error(ppp);
}
}
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 = PPP_MP_CB(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, PPP_MP_CB(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, *tmp;
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 = __skb_peek(list);
tail = NULL;
skb_queue_walk_safe(list, p, tmp) {
again:
if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
/* this can't happen, anyway ignore the skb */
netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
"seq %u < %u\n",
PPP_MP_CB(p)->sequence, seq);
__skb_unlink(p, list);
kfree_skb(p);
continue;
}
if (PPP_MP_CB(p)->sequence != seq) {
u32 oldseq;
/* 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;
oldseq = seq;
seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
minseq + 1: PPP_MP_CB(p)->sequence;
if (ppp->debug & 1)
netdev_printk(KERN_DEBUG, ppp->dev,
"lost frag %u..%u\n",
oldseq, seq-1);
goto again;
}
/*
* 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 (PPP_MP_CB(p)->BEbits & B) {
head = p;
lost = 0;
len = 0;
}
len += p->len;
/* Got a complete packet yet? */
if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
(PPP_MP_CB(head)->BEbits & B)) {
if (len > ppp->mrru + 2) {
++ppp->dev->stats.rx_length_errors;
netdev_printk(KERN_DEBUG, ppp->dev,
"PPP: reconstructed packet"
" is too long (%d)\n", len);
} 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 (PPP_MP_CB(p)->BEbits & E) {
struct sk_buff *tmp2;
skb_queue_reverse_walk_from_safe(list, p, tmp2) {
if (ppp->debug & 1)
netdev_printk(KERN_DEBUG, ppp->dev,
"discarding frag %u\n",
PPP_MP_CB(p)->sequence);
__skb_unlink(p, list);
kfree_skb(p);
}
head = skb_peek(list);
if (!head)
break;
}
++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 (PPP_MP_CB(head)->sequence != ppp->nextseq) {
skb_queue_walk_safe(list, p, tmp) {
if (p == head)
break;
if (ppp->debug & 1)
netdev_printk(KERN_DEBUG, ppp->dev,
"discarding frag %u\n",
PPP_MP_CB(p)->sequence);
__skb_unlink(p, list);
kfree_skb(p);
}
if (ppp->debug & 1)
netdev_printk(KERN_DEBUG, ppp->dev,
" missed pkts %u..%u\n",
ppp->nextseq,
PPP_MP_CB(head)->sequence-1);
++ppp->dev->stats.rx_dropped;
ppp_receive_error(ppp);
}
skb = head;
if (head != tail) {
struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
p = skb_queue_next(list, head);
__skb_unlink(skb, list);
skb_queue_walk_from_safe(list, p, tmp) {
__skb_unlink(p, list);
*fragpp = p;
p->next = NULL;
fragpp = &p->next;
skb->len += p->len;
skb->data_len += p->len;
skb->truesize += p->truesize;
if (p == tail)
break;
}
} else {
__skb_unlink(skb, list);
}
ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
}
return skb;
}
#endif /* CONFIG_PPP_MULTILINK */
/*
* Channel interface.
*/
/* Create a new, unattached ppp channel. */
int ppp_register_channel(struct ppp_channel *chan)
{
return ppp_register_net_channel(current->nsproxy->net_ns, chan);
}
/* Create a new, unattached ppp channel for specified net. */
int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
{
struct channel *pch;
struct ppp_net *pn;
pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
if (!pch)
return -ENOMEM;
pn = ppp_pernet(net);
pch->ppp = NULL;
pch->chan = chan;
pch->chan_net = get_net(net);
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(&pn->all_channels_lock);
pch->file.index = ++pn->last_channel_index;
list_add(&pch->list, &pn->new_channels);
atomic_inc(&channel_count);
spin_unlock_bh(&pn->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;
}
/*
* Return the PPP device interface name of a channel.
*/
char *ppp_dev_name(struct ppp_channel *chan)
{
struct channel *pch = chan->ppp;
char *name = NULL;
if (pch) {
read_lock_bh(&pch->upl);
if (pch->ppp && pch->ppp->dev)
name = pch->ppp->dev->name;
read_unlock_bh(&pch->upl);
}
return name;
}
/*
* 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;
struct ppp_net *pn;
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);
pn = ppp_pernet(pch->chan_net);
spin_lock_bh(&pn->all_channels_lock);
list_del(&pch->list);
spin_unlock_bh(&pn->all_channels_lock);
pch->file.dead = 1;
wake_up_interruptible(&pch->file.rwait);
if (refcount_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)))
goto out;
if (data.length > CCP_MAX_OPTION_LENGTH)
goto out;
if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
goto out;
err = -EINVAL;
if (data.length < 2 || 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->stats64.rx_packets;
st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
st->p.ppp_ibytes = ppp->stats64.rx_bytes;
st->p.ppp_opackets = ppp->stats64.tx_packets;
st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
st->p.ppp_obytes = ppp->stats64.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 int ppp_create_interface(struct net *net, struct file *file, int *unit)
{
struct ppp_config conf = {
.file = file,
.unit = *unit,
.ifname_is_set = false,
};
struct net_device *dev;
struct ppp *ppp;
int err;
dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
if (!dev) {
err = -ENOMEM;
goto err;
}
dev_net_set(dev, net);
dev->rtnl_link_ops = &ppp_link_ops;
rtnl_lock();
err = ppp_dev_configure(net, dev, &conf);
if (err < 0)
goto err_dev;
ppp = netdev_priv(dev);
*unit = ppp->file.index;
rtnl_unlock();
return 0;
err_dev:
rtnl_unlock();
free_netdev(dev);
err:
return err;
}
/*
* 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);
refcount_set(&pf->refcnt, 1);
init_waitqueue_head(&pf->rwait);
}
/*
* 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" */
netdev_err(ppp->dev, "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
if (ppp->pass_filter) {
bpf_prog_destroy(ppp->pass_filter);
ppp->pass_filter = NULL;
}
if (ppp->active_filter) {
bpf_prog_destroy(ppp->active_filter);
ppp->active_filter = NULL;
}
#endif /* CONFIG_PPP_FILTER */
kfree_skb(ppp->xmit_pending);
free_percpu(ppp->xmit_recursion);
free_netdev(ppp->dev);
}
/*
* Locate an existing ppp unit.
* The caller should have locked the all_ppp_mutex.
*/
static struct ppp *
ppp_find_unit(struct ppp_net *pn, int unit)
{
return unit_find(&pn->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(struct ppp_net *pn, int unit)
{
struct channel *pch;
list_for_each_entry(pch, &pn->new_channels, list) {
if (pch->file.index == unit) {
list_move(&pch->list, &pn->all_channels);
return pch;
}
}
list_for_each_entry(pch, &pn->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;
struct ppp_net *pn;
int ret = -ENXIO;
int hdrlen;
pn = ppp_pernet(pch->chan_net);
mutex_lock(&pn->all_ppp_mutex);
ppp = ppp_find_unit(pn, unit);
if (!ppp)
goto out;
write_lock_bh(&pch->upl);
ret = -EINVAL;
if (pch->ppp)
goto outl;
ppp_lock(ppp);
spin_lock_bh(&pch->downl);
if (!pch->chan) {
/* Don't connect unregistered channels */
spin_unlock_bh(&pch->downl);
ppp_unlock(ppp);
ret = -ENOTCONN;
goto outl;
}
spin_unlock_bh(&pch->downl);
if (pch->file.hdrlen > ppp->file.hdrlen)
ppp->file.hdrlen = pch->file.hdrlen;
hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
if (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;
refcount_inc(&ppp->file.refcnt);
ppp_unlock(ppp);
ret = 0;
outl:
write_unlock_bh(&pch->upl);
out:
mutex_unlock(&pn->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 (refcount_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)
{
put_net(pch->chan_net);
pch->chan_net = NULL;
atomic_dec(&channel_count);
if (!pch->file.dead) {
/* "can't happen" */
pr_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))
pr_err("PPP: removing module but units remain!\n");
rtnl_link_unregister(&ppp_link_ops);
unregister_chrdev(PPP_MAJOR, "ppp");
device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
class_destroy(ppp_class);
unregister_pernet_device(&ppp_net_ops);
}
/*
* Units handling. Caller must protect concurrent access
* by holding all_ppp_mutex
*/
/* associate pointer with specified number */
static int unit_set(struct idr *p, void *ptr, int n)
{
int unit;
unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
if (unit == -ENOSPC)
unit = -EINVAL;
return unit;
}
/* get new free unit number and associate pointer with it */
static int unit_get(struct idr *p, void *ptr)
{
return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
}
/* 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_net_channel);
EXPORT_SYMBOL(ppp_register_channel);
EXPORT_SYMBOL(ppp_unregister_channel);
EXPORT_SYMBOL(ppp_channel_index);
EXPORT_SYMBOL(ppp_unit_number);
EXPORT_SYMBOL(ppp_dev_name);
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(PPP_MAJOR, 0);
MODULE_ALIAS_RTNL_LINK("ppp");
MODULE_ALIAS("devname:ppp");
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