drivers/net/ppp/ppp

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This source file includes following definitions.
ppp_pernet
proto_to_npindex
ethertype_to_npindex
ppp_open
ppp_release
ppp_read
ppp_write
ppp_poll
get_filter
ppp_ioctl
ppp_unattached_ioctl
ppp_init_net
ppp_exit_net
ppp_unit_register
ppp_dev_configure
ppp_nl_validate
ppp_nl_newlink
ppp_nl_dellink
ppp_nl_get_size
ppp_nl_fill_info
ppp_nl_get_link_net
ppp_init
ppp_start_xmit
ppp_net_ioctl
ppp_get_stats64
ppp_dev_init
ppp_dev_uninit
ppp_dev_priv_destructor
ppp_setup
__ppp_xmit_process
ppp_xmit_process
pad_compress_skb
ppp_send_frame
ppp_push
ppp_mp_explode
__ppp_channel_push
ppp_channel_push
ppp_do_recv
__ppp_decompress_proto
ppp_decompress_proto
ppp_input
ppp_input_error
ppp_receive_frame
ppp_receive_error
ppp_receive_nonmp_frame
ppp_decompress_frame
ppp_receive_mp_frame
ppp_mp_insert
ppp_mp_reconstruct
ppp_register_channel
ppp_register_net_channel
ppp_channel_index
ppp_unit_number
ppp_dev_name
ppp_unregister_channel
ppp_output_wakeup
ppp_set_compress
ppp_ccp_peek
ppp_ccp_closed
find_comp_entry
ppp_register_compressor
ppp_unregister_compressor
find_compressor
ppp_get_stats
ppp_create_interface
init_ppp_file
ppp_destroy_interface
ppp_find_unit
ppp_find_channel
ppp_connect_channel
ppp_disconnect_channel
ppp_destroy_channel
ppp_cleanup
unit_set
unit_get
unit_put
unit_find
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic PPP layer for Linux.
   4  *
   5  * Copyright 1999-2002 Paul Mackerras.
   6  *
   7  * The generic PPP layer handles the PPP network interfaces, the
   8  * /dev/ppp device, packet and VJ compression, and multilink.
   9  * It talks to PPP `channels' via the interface defined in
  10  * include/linux/ppp_channel.h.  Channels provide the basic means for
  11  * sending and receiving PPP frames on some kind of communications
  12  * channel.
  13  *
  14  * Part of the code in this driver was inspired by the old async-only
  15  * PPP driver, written by Michael Callahan and Al Longyear, and
  16  * subsequently hacked by Paul Mackerras.
  17  *
  18  * ==FILEVERSION 20041108==
  19  */
  20 
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched/signal.h>
  24 #include <linux/kmod.h>
  25 #include <linux/init.h>
  26 #include <linux/list.h>
  27 #include <linux/idr.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/poll.h>
  30 #include <linux/ppp_defs.h>
  31 #include <linux/filter.h>
  32 #include <linux/ppp-ioctl.h>
  33 #include <linux/ppp_channel.h>
  34 #include <linux/ppp-comp.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/rtnetlink.h>
  37 #include <linux/if_arp.h>
  38 #include <linux/ip.h>
  39 #include <linux/tcp.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/rwsem.h>
  42 #include <linux/stddef.h>
  43 #include <linux/device.h>
  44 #include <linux/mutex.h>
  45 #include <linux/slab.h>
  46 #include <linux/file.h>
  47 #include <asm/unaligned.h>
  48 #include <net/slhc_vj.h>
  49 #include <linux/atomic.h>
  50 #include <linux/refcount.h>
  51 
  52 #include <linux/nsproxy.h>
  53 #include <net/net_namespace.h>
  54 #include <net/netns/generic.h>
  55 
  56 #define PPP_VERSION     "2.4.2"
  57 
  58 /*
  59  * Network protocols we support.
  60  */
  61 #define NP_IP   0               /* Internet Protocol V4 */
  62 #define NP_IPV6 1               /* Internet Protocol V6 */
  63 #define NP_IPX  2               /* IPX protocol */
  64 #define NP_AT   3               /* Appletalk protocol */
  65 #define NP_MPLS_UC 4            /* MPLS unicast */
  66 #define NP_MPLS_MC 5            /* MPLS multicast */
  67 #define NUM_NP  6               /* Number of NPs. */
  68 
  69 #define MPHDRLEN        6       /* multilink protocol header length */
  70 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  71 
  72 /*
  73  * An instance of /dev/ppp can be associated with either a ppp
  74  * interface unit or a ppp channel.  In both cases, file->private_data
  75  * points to one of these.
  76  */
  77 struct ppp_file {
  78         enum {
  79                 INTERFACE=1, CHANNEL
  80         }               kind;
  81         struct sk_buff_head xq;         /* pppd transmit queue */
  82         struct sk_buff_head rq;         /* receive queue for pppd */
  83         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  84         refcount_t      refcnt;         /* # refs (incl /dev/ppp attached) */
  85         int             hdrlen;         /* space to leave for headers */
  86         int             index;          /* interface unit / channel number */
  87         int             dead;           /* unit/channel has been shut down */
  88 };
  89 
  90 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  91 
  92 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  93 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  94 
  95 /*
  96  * Data structure to hold primary network stats for which
  97  * we want to use 64 bit storage.  Other network stats
  98  * are stored in dev->stats of the ppp strucute.
  99  */
 100 struct ppp_link_stats {
 101         u64 rx_packets;
 102         u64 tx_packets;
 103         u64 rx_bytes;
 104         u64 tx_bytes;
 105 };
 106 
 107 /*
 108  * Data structure describing one ppp unit.
 109  * A ppp unit corresponds to a ppp network interface device
 110  * and represents a multilink bundle.
 111  * It can have 0 or more ppp channels connected to it.
 112  */
 113 struct ppp {
 114         struct ppp_file file;           /* stuff for read/write/poll 0 */
 115         struct file     *owner;         /* file that owns this unit 48 */
 116         struct list_head channels;      /* list of attached channels 4c */
 117         int             n_channels;     /* how many channels are attached 54 */
 118         spinlock_t      rlock;          /* lock for receive side 58 */
 119         spinlock_t      wlock;          /* lock for transmit side 5c */
 120         int __percpu    *xmit_recursion; /* xmit recursion detect */
 121         int             mru;            /* max receive unit 60 */
 122         unsigned int    flags;          /* control bits 64 */
 123         unsigned int    xstate;         /* transmit state bits 68 */
 124         unsigned int    rstate;         /* receive state bits 6c */
 125         int             debug;          /* debug flags 70 */
 126         struct slcompress *vj;          /* state for VJ header compression */
 127         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 128         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 129         struct compressor *xcomp;       /* transmit packet compressor 8c */
 130         void            *xc_state;      /* its internal state 90 */
 131         struct compressor *rcomp;       /* receive decompressor 94 */
 132         void            *rc_state;      /* its internal state 98 */
 133         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 134         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 135         struct net_device *dev;         /* network interface device a4 */
 136         int             closing;        /* is device closing down? a8 */
 137 #ifdef CONFIG_PPP_MULTILINK
 138         int             nxchan;         /* next channel to send something on */
 139         u32             nxseq;          /* next sequence number to send */
 140         int             mrru;           /* MP: max reconst. receive unit */
 141         u32             nextseq;        /* MP: seq no of next packet */
 142         u32             minseq;         /* MP: min of most recent seqnos */
 143         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 144 #endif /* CONFIG_PPP_MULTILINK */
 145 #ifdef CONFIG_PPP_FILTER
 146         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 147         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 148 #endif /* CONFIG_PPP_FILTER */
 149         struct net      *ppp_net;       /* the net we belong to */
 150         struct ppp_link_stats stats64;  /* 64 bit network stats */
 151 };
 152 
 153 /*
 154  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 155  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 156  * SC_MUST_COMP
 157  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 158  * Bits in xstate: SC_COMP_RUN
 159  */
 160 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 161                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 162                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 163 
 164 /*
 165  * Private data structure for each channel.
 166  * This includes the data structure used for multilink.
 167  */
 168 struct channel {
 169         struct ppp_file file;           /* stuff for read/write/poll */
 170         struct list_head list;          /* link in all/new_channels list */
 171         struct ppp_channel *chan;       /* public channel data structure */
 172         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 173         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 174         struct ppp      *ppp;           /* ppp unit we're connected to */
 175         struct net      *chan_net;      /* the net channel belongs to */
 176         struct list_head clist;         /* link in list of channels per unit */
 177         rwlock_t        upl;            /* protects `ppp' */
 178 #ifdef CONFIG_PPP_MULTILINK
 179         u8              avail;          /* flag used in multilink stuff */
 180         u8              had_frag;       /* >= 1 fragments have been sent */
 181         u32             lastseq;        /* MP: last sequence # received */
 182         int             speed;          /* speed of the corresponding ppp channel*/
 183 #endif /* CONFIG_PPP_MULTILINK */
 184 };
 185 
 186 struct ppp_config {
 187         struct file *file;
 188         s32 unit;
 189         bool ifname_is_set;
 190 };
 191 
 192 /*
 193  * SMP locking issues:
 194  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 195  * list and the ppp.n_channels field, you need to take both locks
 196  * before you modify them.
 197  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 198  * channel.downl.
 199  */
 200 
 201 static DEFINE_MUTEX(ppp_mutex);
 202 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 203 static atomic_t channel_count = ATOMIC_INIT(0);
 204 
 205 /* per-net private data for this module */
 206 static unsigned int ppp_net_id __read_mostly;
 207 struct ppp_net {
 208         /* units to ppp mapping */
 209         struct idr units_idr;
 210 
 211         /*
 212          * all_ppp_mutex protects the units_idr mapping.
 213          * It also ensures that finding a ppp unit in the units_idr
 214          * map and updating its file.refcnt field is atomic.
 215          */
 216         struct mutex all_ppp_mutex;
 217 
 218         /* channels */
 219         struct list_head all_channels;
 220         struct list_head new_channels;
 221         int last_channel_index;
 222 
 223         /*
 224          * all_channels_lock protects all_channels and
 225          * last_channel_index, and the atomicity of find
 226          * a channel and updating its file.refcnt field.
 227          */
 228         spinlock_t all_channels_lock;
 229 };
 230 
 231 /* Get the PPP protocol number from a skb */
 232 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 233 
 234 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 235 #define PPP_MAX_RQLEN   32
 236 
 237 /*
 238  * Maximum number of multilink fragments queued up.
 239  * This has to be large enough to cope with the maximum latency of
 240  * the slowest channel relative to the others.  Strictly it should
 241  * depend on the number of channels and their characteristics.
 242  */
 243 #define PPP_MP_MAX_QLEN 128
 244 
 245 /* Multilink header bits. */
 246 #define B       0x80            /* this fragment begins a packet */
 247 #define E       0x40            /* this fragment ends a packet */
 248 
 249 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 250 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 251 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 252 
 253 /* Prototypes. */
 254 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 255                         struct file *file, unsigned int cmd, unsigned long arg);
 256 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 257 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 258 static void ppp_push(struct ppp *ppp);
 259 static void ppp_channel_push(struct channel *pch);
 260 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 261                               struct channel *pch);
 262 static void ppp_receive_error(struct ppp *ppp);
 263 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 264 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 265                                             struct sk_buff *skb);
 266 #ifdef CONFIG_PPP_MULTILINK
 267 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 268                                 struct channel *pch);
 269 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 270 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 271 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 272 #endif /* CONFIG_PPP_MULTILINK */
 273 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 274 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 275 static void ppp_ccp_closed(struct ppp *ppp);
 276 static struct compressor *find_compressor(int type);
 277 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 278 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 279 static void init_ppp_file(struct ppp_file *pf, int kind);
 280 static void ppp_destroy_interface(struct ppp *ppp);
 281 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 282 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 283 static int ppp_connect_channel(struct channel *pch, int unit);
 284 static int ppp_disconnect_channel(struct channel *pch);
 285 static void ppp_destroy_channel(struct channel *pch);
 286 static int unit_get(struct idr *p, void *ptr);
 287 static int unit_set(struct idr *p, void *ptr, int n);
 288 static void unit_put(struct idr *p, int n);
 289 static void *unit_find(struct idr *p, int n);
 290 static void ppp_setup(struct net_device *dev);
 291 
 292 static const struct net_device_ops ppp_netdev_ops;
 293 
 294 static struct class *ppp_class;
 295 
 296 /* per net-namespace data */
 297 static inline struct ppp_net *ppp_pernet(struct net *net)
 298 {
 299         BUG_ON(!net);
 300 
 301         return net_generic(net, ppp_net_id);
 302 }
 303 
 304 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 305 static inline int proto_to_npindex(int proto)
 306 {
 307         switch (proto) {
 308         case PPP_IP:
 309                 return NP_IP;
 310         case PPP_IPV6:
 311                 return NP_IPV6;
 312         case PPP_IPX:
 313                 return NP_IPX;
 314         case PPP_AT:
 315                 return NP_AT;
 316         case PPP_MPLS_UC:
 317                 return NP_MPLS_UC;
 318         case PPP_MPLS_MC:
 319                 return NP_MPLS_MC;
 320         }
 321         return -EINVAL;
 322 }
 323 
 324 /* Translates an NP index into a PPP protocol number */
 325 static const int npindex_to_proto[NUM_NP] = {
 326         PPP_IP,
 327         PPP_IPV6,
 328         PPP_IPX,
 329         PPP_AT,
 330         PPP_MPLS_UC,
 331         PPP_MPLS_MC,
 332 };
 333 
 334 /* Translates an ethertype into an NP index */
 335 static inline int ethertype_to_npindex(int ethertype)
 336 {
 337         switch (ethertype) {
 338         case ETH_P_IP:
 339                 return NP_IP;
 340         case ETH_P_IPV6:
 341                 return NP_IPV6;
 342         case ETH_P_IPX:
 343                 return NP_IPX;
 344         case ETH_P_PPPTALK:
 345         case ETH_P_ATALK:
 346                 return NP_AT;
 347         case ETH_P_MPLS_UC:
 348                 return NP_MPLS_UC;
 349         case ETH_P_MPLS_MC:
 350                 return NP_MPLS_MC;
 351         }
 352         return -1;
 353 }
 354 
 355 /* Translates an NP index into an ethertype */
 356 static const int npindex_to_ethertype[NUM_NP] = {
 357         ETH_P_IP,
 358         ETH_P_IPV6,
 359         ETH_P_IPX,
 360         ETH_P_PPPTALK,
 361         ETH_P_MPLS_UC,
 362         ETH_P_MPLS_MC,
 363 };
 364 
 365 /*
 366  * Locking shorthand.
 367  */
 368 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 369 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 370 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 371 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 372 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 373                                      ppp_recv_lock(ppp); } while (0)
 374 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 375                                      ppp_xmit_unlock(ppp); } while (0)
 376 
 377 /*
 378  * /dev/ppp device routines.
 379  * The /dev/ppp device is used by pppd to control the ppp unit.
 380  * It supports the read, write, ioctl and poll functions.
 381  * Open instances of /dev/ppp can be in one of three states:
 382  * unattached, attached to a ppp unit, or attached to a ppp channel.
 383  */
 384 static int ppp_open(struct inode *inode, struct file *file)
 385 {
 386         /*
 387          * This could (should?) be enforced by the permissions on /dev/ppp.
 388          */
 389         if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
 390                 return -EPERM;
 391         return 0;
 392 }
 393 
 394 static int ppp_release(struct inode *unused, struct file *file)
 395 {
 396         struct ppp_file *pf = file->private_data;
 397         struct ppp *ppp;
 398 
 399         if (pf) {
 400                 file->private_data = NULL;
 401                 if (pf->kind == INTERFACE) {
 402                         ppp = PF_TO_PPP(pf);
 403                         rtnl_lock();
 404                         if (file == ppp->owner)
 405                                 unregister_netdevice(ppp->dev);
 406                         rtnl_unlock();
 407                 }
 408                 if (refcount_dec_and_test(&pf->refcnt)) {
 409                         switch (pf->kind) {
 410                         case INTERFACE:
 411                                 ppp_destroy_interface(PF_TO_PPP(pf));
 412                                 break;
 413                         case CHANNEL:
 414                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 415                                 break;
 416                         }
 417                 }
 418         }
 419         return 0;
 420 }
 421 
 422 static ssize_t ppp_read(struct file *file, char __user *buf,
 423                         size_t count, loff_t *ppos)
 424 {
 425         struct ppp_file *pf = file->private_data;
 426         DECLARE_WAITQUEUE(wait, current);
 427         ssize_t ret;
 428         struct sk_buff *skb = NULL;
 429         struct iovec iov;
 430         struct iov_iter to;
 431 
 432         ret = count;
 433 
 434         if (!pf)
 435                 return -ENXIO;
 436         add_wait_queue(&pf->rwait, &wait);
 437         for (;;) {
 438                 set_current_state(TASK_INTERRUPTIBLE);
 439                 skb = skb_dequeue(&pf->rq);
 440                 if (skb)
 441                         break;
 442                 ret = 0;
 443                 if (pf->dead)
 444                         break;
 445                 if (pf->kind == INTERFACE) {
 446                         /*
 447                          * Return 0 (EOF) on an interface that has no
 448                          * channels connected, unless it is looping
 449                          * network traffic (demand mode).
 450                          */
 451                         struct ppp *ppp = PF_TO_PPP(pf);
 452 
 453                         ppp_recv_lock(ppp);
 454                         if (ppp->n_channels == 0 &&
 455                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 456                                 ppp_recv_unlock(ppp);
 457                                 break;
 458                         }
 459                         ppp_recv_unlock(ppp);
 460                 }
 461                 ret = -EAGAIN;
 462                 if (file->f_flags & O_NONBLOCK)
 463                         break;
 464                 ret = -ERESTARTSYS;
 465                 if (signal_pending(current))
 466                         break;
 467                 schedule();
 468         }
 469         set_current_state(TASK_RUNNING);
 470         remove_wait_queue(&pf->rwait, &wait);
 471 
 472         if (!skb)
 473                 goto out;
 474 
 475         ret = -EOVERFLOW;
 476         if (skb->len > count)
 477                 goto outf;
 478         ret = -EFAULT;
 479         iov.iov_base = buf;
 480         iov.iov_len = count;
 481         iov_iter_init(&to, READ, &iov, 1, count);
 482         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 483                 goto outf;
 484         ret = skb->len;
 485 
 486  outf:
 487         kfree_skb(skb);
 488  out:
 489         return ret;
 490 }
 491 
 492 static ssize_t ppp_write(struct file *file, const char __user *buf,
 493                          size_t count, loff_t *ppos)
 494 {
 495         struct ppp_file *pf = file->private_data;
 496         struct sk_buff *skb;
 497         ssize_t ret;
 498 
 499         if (!pf)
 500                 return -ENXIO;
 501         ret = -ENOMEM;
 502         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 503         if (!skb)
 504                 goto out;
 505         skb_reserve(skb, pf->hdrlen);
 506         ret = -EFAULT;
 507         if (copy_from_user(skb_put(skb, count), buf, count)) {
 508                 kfree_skb(skb);
 509                 goto out;
 510         }
 511 
 512         switch (pf->kind) {
 513         case INTERFACE:
 514                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 515                 break;
 516         case CHANNEL:
 517                 skb_queue_tail(&pf->xq, skb);
 518                 ppp_channel_push(PF_TO_CHANNEL(pf));
 519                 break;
 520         }
 521 
 522         ret = count;
 523 
 524  out:
 525         return ret;
 526 }
 527 
 528 /* No kernel lock - fine */
 529 static __poll_t ppp_poll(struct file *file, poll_table *wait)
 530 {
 531         struct ppp_file *pf = file->private_data;
 532         __poll_t mask;
 533 
 534         if (!pf)
 535                 return 0;
 536         poll_wait(file, &pf->rwait, wait);
 537         mask = EPOLLOUT | EPOLLWRNORM;
 538         if (skb_peek(&pf->rq))
 539                 mask |= EPOLLIN | EPOLLRDNORM;
 540         if (pf->dead)
 541                 mask |= EPOLLHUP;
 542         else if (pf->kind == INTERFACE) {
 543                 /* see comment in ppp_read */
 544                 struct ppp *ppp = PF_TO_PPP(pf);
 545 
 546                 ppp_recv_lock(ppp);
 547                 if (ppp->n_channels == 0 &&
 548                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 549                         mask |= EPOLLIN | EPOLLRDNORM;
 550                 ppp_recv_unlock(ppp);
 551         }
 552 
 553         return mask;
 554 }
 555 
 556 #ifdef CONFIG_PPP_FILTER
 557 static int get_filter(void __user *arg, struct sock_filter **p)
 558 {
 559         struct sock_fprog uprog;
 560         struct sock_filter *code = NULL;
 561         int len;
 562 
 563         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 564                 return -EFAULT;
 565 
 566         if (!uprog.len) {
 567                 *p = NULL;
 568                 return 0;
 569         }
 570 
 571         len = uprog.len * sizeof(struct sock_filter);
 572         code = memdup_user(uprog.filter, len);
 573         if (IS_ERR(code))
 574                 return PTR_ERR(code);
 575 
 576         *p = code;
 577         return uprog.len;
 578 }
 579 #endif /* CONFIG_PPP_FILTER */
 580 
 581 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 582 {
 583         struct ppp_file *pf;
 584         struct ppp *ppp;
 585         int err = -EFAULT, val, val2, i;
 586         struct ppp_idle idle;
 587         struct npioctl npi;
 588         int unit, cflags;
 589         struct slcompress *vj;
 590         void __user *argp = (void __user *)arg;
 591         int __user *p = argp;
 592 
 593         mutex_lock(&ppp_mutex);
 594 
 595         pf = file->private_data;
 596         if (!pf) {
 597                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 598                                            pf, file, cmd, arg);
 599                 goto out;
 600         }
 601 
 602         if (cmd == PPPIOCDETACH) {
 603                 /*
 604                  * PPPIOCDETACH is no longer supported as it was heavily broken,
 605                  * and is only known to have been used by pppd older than
 606                  * ppp-2.4.2 (released November 2003).
 607                  */
 608                 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
 609                              current->comm, current->pid);
 610                 err = -EINVAL;
 611                 goto out;
 612         }
 613 
 614         if (pf->kind == CHANNEL) {
 615                 struct channel *pch;
 616                 struct ppp_channel *chan;
 617 
 618                 pch = PF_TO_CHANNEL(pf);
 619 
 620                 switch (cmd) {
 621                 case PPPIOCCONNECT:
 622                         if (get_user(unit, p))
 623                                 break;
 624                         err = ppp_connect_channel(pch, unit);
 625                         break;
 626 
 627                 case PPPIOCDISCONN:
 628                         err = ppp_disconnect_channel(pch);
 629                         break;
 630 
 631                 default:
 632                         down_read(&pch->chan_sem);
 633                         chan = pch->chan;
 634                         err = -ENOTTY;
 635                         if (chan && chan->ops->ioctl)
 636                                 err = chan->ops->ioctl(chan, cmd, arg);
 637                         up_read(&pch->chan_sem);
 638                 }
 639                 goto out;
 640         }
 641 
 642         if (pf->kind != INTERFACE) {
 643                 /* can't happen */
 644                 pr_err("PPP: not interface or channel??\n");
 645                 err = -EINVAL;
 646                 goto out;
 647         }
 648 
 649         ppp = PF_TO_PPP(pf);
 650         switch (cmd) {
 651         case PPPIOCSMRU:
 652                 if (get_user(val, p))
 653                         break;
 654                 ppp->mru = val;
 655                 err = 0;
 656                 break;
 657 
 658         case PPPIOCSFLAGS:
 659                 if (get_user(val, p))
 660                         break;
 661                 ppp_lock(ppp);
 662                 cflags = ppp->flags & ~val;
 663 #ifdef CONFIG_PPP_MULTILINK
 664                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 665                         ppp->nextseq = 0;
 666 #endif
 667                 ppp->flags = val & SC_FLAG_BITS;
 668                 ppp_unlock(ppp);
 669                 if (cflags & SC_CCP_OPEN)
 670                         ppp_ccp_closed(ppp);
 671                 err = 0;
 672                 break;
 673 
 674         case PPPIOCGFLAGS:
 675                 val = ppp->flags | ppp->xstate | ppp->rstate;
 676                 if (put_user(val, p))
 677                         break;
 678                 err = 0;
 679                 break;
 680 
 681         case PPPIOCSCOMPRESS:
 682                 err = ppp_set_compress(ppp, arg);
 683                 break;
 684 
 685         case PPPIOCGUNIT:
 686                 if (put_user(ppp->file.index, p))
 687                         break;
 688                 err = 0;
 689                 break;
 690 
 691         case PPPIOCSDEBUG:
 692                 if (get_user(val, p))
 693                         break;
 694                 ppp->debug = val;
 695                 err = 0;
 696                 break;
 697 
 698         case PPPIOCGDEBUG:
 699                 if (put_user(ppp->debug, p))
 700                         break;
 701                 err = 0;
 702                 break;
 703 
 704         case PPPIOCGIDLE:
 705                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 706                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 707                 if (copy_to_user(argp, &idle, sizeof(idle)))
 708                         break;
 709                 err = 0;
 710                 break;
 711 
 712         case PPPIOCSMAXCID:
 713                 if (get_user(val, p))
 714                         break;
 715                 val2 = 15;
 716                 if ((val >> 16) != 0) {
 717                         val2 = val >> 16;
 718                         val &= 0xffff;
 719                 }
 720                 vj = slhc_init(val2+1, val+1);
 721                 if (IS_ERR(vj)) {
 722                         err = PTR_ERR(vj);
 723                         break;
 724                 }
 725                 ppp_lock(ppp);
 726                 if (ppp->vj)
 727                         slhc_free(ppp->vj);
 728                 ppp->vj = vj;
 729                 ppp_unlock(ppp);
 730                 err = 0;
 731                 break;
 732 
 733         case PPPIOCGNPMODE:
 734         case PPPIOCSNPMODE:
 735                 if (copy_from_user(&npi, argp, sizeof(npi)))
 736                         break;
 737                 err = proto_to_npindex(npi.protocol);
 738                 if (err < 0)
 739                         break;
 740                 i = err;
 741                 if (cmd == PPPIOCGNPMODE) {
 742                         err = -EFAULT;
 743                         npi.mode = ppp->npmode[i];
 744                         if (copy_to_user(argp, &npi, sizeof(npi)))
 745                                 break;
 746                 } else {
 747                         ppp->npmode[i] = npi.mode;
 748                         /* we may be able to transmit more packets now (??) */
 749                         netif_wake_queue(ppp->dev);
 750                 }
 751                 err = 0;
 752                 break;
 753 
 754 #ifdef CONFIG_PPP_FILTER
 755         case PPPIOCSPASS:
 756         {
 757                 struct sock_filter *code;
 758 
 759                 err = get_filter(argp, &code);
 760                 if (err >= 0) {
 761                         struct bpf_prog *pass_filter = NULL;
 762                         struct sock_fprog_kern fprog = {
 763                                 .len = err,
 764                                 .filter = code,
 765                         };
 766 
 767                         err = 0;
 768                         if (fprog.filter)
 769                                 err = bpf_prog_create(&pass_filter, &fprog);
 770                         if (!err) {
 771                                 ppp_lock(ppp);
 772                                 if (ppp->pass_filter)
 773                                         bpf_prog_destroy(ppp->pass_filter);
 774                                 ppp->pass_filter = pass_filter;
 775                                 ppp_unlock(ppp);
 776                         }
 777                         kfree(code);
 778                 }
 779                 break;
 780         }
 781         case PPPIOCSACTIVE:
 782         {
 783                 struct sock_filter *code;
 784 
 785                 err = get_filter(argp, &code);
 786                 if (err >= 0) {
 787                         struct bpf_prog *active_filter = NULL;
 788                         struct sock_fprog_kern fprog = {
 789                                 .len = err,
 790                                 .filter = code,
 791                         };
 792 
 793                         err = 0;
 794                         if (fprog.filter)
 795                                 err = bpf_prog_create(&active_filter, &fprog);
 796                         if (!err) {
 797                                 ppp_lock(ppp);
 798                                 if (ppp->active_filter)
 799                                         bpf_prog_destroy(ppp->active_filter);
 800                                 ppp->active_filter = active_filter;
 801                                 ppp_unlock(ppp);
 802                         }
 803                         kfree(code);
 804                 }
 805                 break;
 806         }
 807 #endif /* CONFIG_PPP_FILTER */
 808 
 809 #ifdef CONFIG_PPP_MULTILINK
 810         case PPPIOCSMRRU:
 811                 if (get_user(val, p))
 812                         break;
 813                 ppp_recv_lock(ppp);
 814                 ppp->mrru = val;
 815                 ppp_recv_unlock(ppp);
 816                 err = 0;
 817                 break;
 818 #endif /* CONFIG_PPP_MULTILINK */
 819 
 820         default:
 821                 err = -ENOTTY;
 822         }
 823 
 824 out:
 825         mutex_unlock(&ppp_mutex);
 826 
 827         return err;
 828 }
 829 
 830 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 831                         struct file *file, unsigned int cmd, unsigned long arg)
 832 {
 833         int unit, err = -EFAULT;
 834         struct ppp *ppp;
 835         struct channel *chan;
 836         struct ppp_net *pn;
 837         int __user *p = (int __user *)arg;
 838 
 839         switch (cmd) {
 840         case PPPIOCNEWUNIT:
 841                 /* Create a new ppp unit */
 842                 if (get_user(unit, p))
 843                         break;
 844                 err = ppp_create_interface(net, file, &unit);
 845                 if (err < 0)
 846                         break;
 847 
 848                 err = -EFAULT;
 849                 if (put_user(unit, p))
 850                         break;
 851                 err = 0;
 852                 break;
 853 
 854         case PPPIOCATTACH:
 855                 /* Attach to an existing ppp unit */
 856                 if (get_user(unit, p))
 857                         break;
 858                 err = -ENXIO;
 859                 pn = ppp_pernet(net);
 860                 mutex_lock(&pn->all_ppp_mutex);
 861                 ppp = ppp_find_unit(pn, unit);
 862                 if (ppp) {
 863                         refcount_inc(&ppp->file.refcnt);
 864                         file->private_data = &ppp->file;
 865                         err = 0;
 866                 }
 867                 mutex_unlock(&pn->all_ppp_mutex);
 868                 break;
 869 
 870         case PPPIOCATTCHAN:
 871                 if (get_user(unit, p))
 872                         break;
 873                 err = -ENXIO;
 874                 pn = ppp_pernet(net);
 875                 spin_lock_bh(&pn->all_channels_lock);
 876                 chan = ppp_find_channel(pn, unit);
 877                 if (chan) {
 878                         refcount_inc(&chan->file.refcnt);
 879                         file->private_data = &chan->file;
 880                         err = 0;
 881                 }
 882                 spin_unlock_bh(&pn->all_channels_lock);
 883                 break;
 884 
 885         default:
 886                 err = -ENOTTY;
 887         }
 888 
 889         return err;
 890 }
 891 
 892 static const struct file_operations ppp_device_fops = {
 893         .owner          = THIS_MODULE,
 894         .read           = ppp_read,
 895         .write          = ppp_write,
 896         .poll           = ppp_poll,
 897         .unlocked_ioctl = ppp_ioctl,
 898         .open           = ppp_open,
 899         .release        = ppp_release,
 900         .llseek         = noop_llseek,
 901 };
 902 
 903 static __net_init int ppp_init_net(struct net *net)
 904 {
 905         struct ppp_net *pn = net_generic(net, ppp_net_id);
 906 
 907         idr_init(&pn->units_idr);
 908         mutex_init(&pn->all_ppp_mutex);
 909 
 910         INIT_LIST_HEAD(&pn->all_channels);
 911         INIT_LIST_HEAD(&pn->new_channels);
 912 
 913         spin_lock_init(&pn->all_channels_lock);
 914 
 915         return 0;
 916 }
 917 
 918 static __net_exit void ppp_exit_net(struct net *net)
 919 {
 920         struct ppp_net *pn = net_generic(net, ppp_net_id);
 921         struct net_device *dev;
 922         struct net_device *aux;
 923         struct ppp *ppp;
 924         LIST_HEAD(list);
 925         int id;
 926 
 927         rtnl_lock();
 928         for_each_netdev_safe(net, dev, aux) {
 929                 if (dev->netdev_ops == &ppp_netdev_ops)
 930                         unregister_netdevice_queue(dev, &list);
 931         }
 932 
 933         idr_for_each_entry(&pn->units_idr, ppp, id)
 934                 /* Skip devices already unregistered by previous loop */
 935                 if (!net_eq(dev_net(ppp->dev), net))
 936                         unregister_netdevice_queue(ppp->dev, &list);
 937 
 938         unregister_netdevice_many(&list);
 939         rtnl_unlock();
 940 
 941         mutex_destroy(&pn->all_ppp_mutex);
 942         idr_destroy(&pn->units_idr);
 943         WARN_ON_ONCE(!list_empty(&pn->all_channels));
 944         WARN_ON_ONCE(!list_empty(&pn->new_channels));
 945 }
 946 
 947 static struct pernet_operations ppp_net_ops = {
 948         .init = ppp_init_net,
 949         .exit = ppp_exit_net,
 950         .id   = &ppp_net_id,
 951         .size = sizeof(struct ppp_net),
 952 };
 953 
 954 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
 955 {
 956         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
 957         int ret;
 958 
 959         mutex_lock(&pn->all_ppp_mutex);
 960 
 961         if (unit < 0) {
 962                 ret = unit_get(&pn->units_idr, ppp);
 963                 if (ret < 0)
 964                         goto err;
 965         } else {
 966                 /* Caller asked for a specific unit number. Fail with -EEXIST
 967                  * if unavailable. For backward compatibility, return -EEXIST
 968                  * too if idr allocation fails; this makes pppd retry without
 969                  * requesting a specific unit number.
 970                  */
 971                 if (unit_find(&pn->units_idr, unit)) {
 972                         ret = -EEXIST;
 973                         goto err;
 974                 }
 975                 ret = unit_set(&pn->units_idr, ppp, unit);
 976                 if (ret < 0) {
 977                         /* Rewrite error for backward compatibility */
 978                         ret = -EEXIST;
 979                         goto err;
 980                 }
 981         }
 982         ppp->file.index = ret;
 983 
 984         if (!ifname_is_set)
 985                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
 986 
 987         mutex_unlock(&pn->all_ppp_mutex);
 988 
 989         ret = register_netdevice(ppp->dev);
 990         if (ret < 0)
 991                 goto err_unit;
 992 
 993         atomic_inc(&ppp_unit_count);
 994 
 995         return 0;
 996 
 997 err_unit:
 998         mutex_lock(&pn->all_ppp_mutex);
 999         unit_put(&pn->units_idr, ppp->file.index);
1000 err:
1001         mutex_unlock(&pn->all_ppp_mutex);
1002 
1003         return ret;
1004 }
1005 
1006 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1007                              const struct ppp_config *conf)
1008 {
1009         struct ppp *ppp = netdev_priv(dev);
1010         int indx;
1011         int err;
1012         int cpu;
1013 
1014         ppp->dev = dev;
1015         ppp->ppp_net = src_net;
1016         ppp->mru = PPP_MRU;
1017         ppp->owner = conf->file;
1018 
1019         init_ppp_file(&ppp->file, INTERFACE);
1020         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1021 
1022         for (indx = 0; indx < NUM_NP; ++indx)
1023                 ppp->npmode[indx] = NPMODE_PASS;
1024         INIT_LIST_HEAD(&ppp->channels);
1025         spin_lock_init(&ppp->rlock);
1026         spin_lock_init(&ppp->wlock);
1027 
1028         ppp->xmit_recursion = alloc_percpu(int);
1029         if (!ppp->xmit_recursion) {
1030                 err = -ENOMEM;
1031                 goto err1;
1032         }
1033         for_each_possible_cpu(cpu)
1034                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1035 
1036 #ifdef CONFIG_PPP_MULTILINK
1037         ppp->minseq = -1;
1038         skb_queue_head_init(&ppp->mrq);
1039 #endif /* CONFIG_PPP_MULTILINK */
1040 #ifdef CONFIG_PPP_FILTER
1041         ppp->pass_filter = NULL;
1042         ppp->active_filter = NULL;
1043 #endif /* CONFIG_PPP_FILTER */
1044 
1045         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1046         if (err < 0)
1047                 goto err2;
1048 
1049         conf->file->private_data = &ppp->file;
1050 
1051         return 0;
1052 err2:
1053         free_percpu(ppp->xmit_recursion);
1054 err1:
1055         return err;
1056 }
1057 
1058 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1059         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1060 };
1061 
1062 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1063                            struct netlink_ext_ack *extack)
1064 {
1065         if (!data)
1066                 return -EINVAL;
1067 
1068         if (!data[IFLA_PPP_DEV_FD])
1069                 return -EINVAL;
1070         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1071                 return -EBADF;
1072 
1073         return 0;
1074 }
1075 
1076 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1077                           struct nlattr *tb[], struct nlattr *data[],
1078                           struct netlink_ext_ack *extack)
1079 {
1080         struct ppp_config conf = {
1081                 .unit = -1,
1082                 .ifname_is_set = true,
1083         };
1084         struct file *file;
1085         int err;
1086 
1087         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1088         if (!file)
1089                 return -EBADF;
1090 
1091         /* rtnl_lock is already held here, but ppp_create_interface() locks
1092          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1093          * possible deadlock due to lock order inversion, at the cost of
1094          * pushing the problem back to userspace.
1095          */
1096         if (!mutex_trylock(&ppp_mutex)) {
1097                 err = -EBUSY;
1098                 goto out;
1099         }
1100 
1101         if (file->f_op != &ppp_device_fops || file->private_data) {
1102                 err = -EBADF;
1103                 goto out_unlock;
1104         }
1105 
1106         conf.file = file;
1107 
1108         /* Don't use device name generated by the rtnetlink layer when ifname
1109          * isn't specified. Let ppp_dev_configure() set the device name using
1110          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1111          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1112          */
1113         if (!tb[IFLA_IFNAME])
1114                 conf.ifname_is_set = false;
1115 
1116         err = ppp_dev_configure(src_net, dev, &conf);
1117 
1118 out_unlock:
1119         mutex_unlock(&ppp_mutex);
1120 out:
1121         fput(file);
1122 
1123         return err;
1124 }
1125 
1126 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1127 {
1128         unregister_netdevice_queue(dev, head);
1129 }
1130 
1131 static size_t ppp_nl_get_size(const struct net_device *dev)
1132 {
1133         return 0;
1134 }
1135 
1136 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1137 {
1138         return 0;
1139 }
1140 
1141 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1142 {
1143         struct ppp *ppp = netdev_priv(dev);
1144 
1145         return ppp->ppp_net;
1146 }
1147 
1148 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1149         .kind           = "ppp",
1150         .maxtype        = IFLA_PPP_MAX,
1151         .policy         = ppp_nl_policy,
1152         .priv_size      = sizeof(struct ppp),
1153         .setup          = ppp_setup,
1154         .validate       = ppp_nl_validate,
1155         .newlink        = ppp_nl_newlink,
1156         .dellink        = ppp_nl_dellink,
1157         .get_size       = ppp_nl_get_size,
1158         .fill_info      = ppp_nl_fill_info,
1159         .get_link_net   = ppp_nl_get_link_net,
1160 };
1161 
1162 #define PPP_MAJOR       108
1163 
1164 /* Called at boot time if ppp is compiled into the kernel,
1165    or at module load time (from init_module) if compiled as a module. */
1166 static int __init ppp_init(void)
1167 {
1168         int err;
1169 
1170         pr_info("PPP generic driver version " PPP_VERSION "\n");
1171 
1172         err = register_pernet_device(&ppp_net_ops);
1173         if (err) {
1174                 pr_err("failed to register PPP pernet device (%d)\n", err);
1175                 goto out;
1176         }
1177 
1178         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1179         if (err) {
1180                 pr_err("failed to register PPP device (%d)\n", err);
1181                 goto out_net;
1182         }
1183 
1184         ppp_class = class_create(THIS_MODULE, "ppp");
1185         if (IS_ERR(ppp_class)) {
1186                 err = PTR_ERR(ppp_class);
1187                 goto out_chrdev;
1188         }
1189 
1190         err = rtnl_link_register(&ppp_link_ops);
1191         if (err) {
1192                 pr_err("failed to register rtnetlink PPP handler\n");
1193                 goto out_class;
1194         }
1195 
1196         /* not a big deal if we fail here :-) */
1197         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1198 
1199         return 0;
1200 
1201 out_class:
1202         class_destroy(ppp_class);
1203 out_chrdev:
1204         unregister_chrdev(PPP_MAJOR, "ppp");
1205 out_net:
1206         unregister_pernet_device(&ppp_net_ops);
1207 out:
1208         return err;
1209 }
1210 
1211 /*
1212  * Network interface unit routines.
1213  */
1214 static netdev_tx_t
1215 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1216 {
1217         struct ppp *ppp = netdev_priv(dev);
1218         int npi, proto;
1219         unsigned char *pp;
1220 
1221         npi = ethertype_to_npindex(ntohs(skb->protocol));
1222         if (npi < 0)
1223                 goto outf;
1224 
1225         /* Drop, accept or reject the packet */
1226         switch (ppp->npmode[npi]) {
1227         case NPMODE_PASS:
1228                 break;
1229         case NPMODE_QUEUE:
1230                 /* it would be nice to have a way to tell the network
1231                    system to queue this one up for later. */
1232                 goto outf;
1233         case NPMODE_DROP:
1234         case NPMODE_ERROR:
1235                 goto outf;
1236         }
1237 
1238         /* Put the 2-byte PPP protocol number on the front,
1239            making sure there is room for the address and control fields. */
1240         if (skb_cow_head(skb, PPP_HDRLEN))
1241                 goto outf;
1242 
1243         pp = skb_push(skb, 2);
1244         proto = npindex_to_proto[npi];
1245         put_unaligned_be16(proto, pp);
1246 
1247         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1248         ppp_xmit_process(ppp, skb);
1249 
1250         return NETDEV_TX_OK;
1251 
1252  outf:
1253         kfree_skb(skb);
1254         ++dev->stats.tx_dropped;
1255         return NETDEV_TX_OK;
1256 }
1257 
1258 static int
1259 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1260 {
1261         struct ppp *ppp = netdev_priv(dev);
1262         int err = -EFAULT;
1263         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1264         struct ppp_stats stats;
1265         struct ppp_comp_stats cstats;
1266         char *vers;
1267 
1268         switch (cmd) {
1269         case SIOCGPPPSTATS:
1270                 ppp_get_stats(ppp, &stats);
1271                 if (copy_to_user(addr, &stats, sizeof(stats)))
1272                         break;
1273                 err = 0;
1274                 break;
1275 
1276         case SIOCGPPPCSTATS:
1277                 memset(&cstats, 0, sizeof(cstats));
1278                 if (ppp->xc_state)
1279                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1280                 if (ppp->rc_state)
1281                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1282                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1283                         break;
1284                 err = 0;
1285                 break;
1286 
1287         case SIOCGPPPVER:
1288                 vers = PPP_VERSION;
1289                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1290                         break;
1291                 err = 0;
1292                 break;
1293 
1294         default:
1295                 err = -EINVAL;
1296         }
1297 
1298         return err;
1299 }
1300 
1301 static void
1302 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1303 {
1304         struct ppp *ppp = netdev_priv(dev);
1305 
1306         ppp_recv_lock(ppp);
1307         stats64->rx_packets = ppp->stats64.rx_packets;
1308         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1309         ppp_recv_unlock(ppp);
1310 
1311         ppp_xmit_lock(ppp);
1312         stats64->tx_packets = ppp->stats64.tx_packets;
1313         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1314         ppp_xmit_unlock(ppp);
1315 
1316         stats64->rx_errors        = dev->stats.rx_errors;
1317         stats64->tx_errors        = dev->stats.tx_errors;
1318         stats64->rx_dropped       = dev->stats.rx_dropped;
1319         stats64->tx_dropped       = dev->stats.tx_dropped;
1320         stats64->rx_length_errors = dev->stats.rx_length_errors;
1321 }
1322 
1323 static int ppp_dev_init(struct net_device *dev)
1324 {
1325         struct ppp *ppp;
1326 
1327         ppp = netdev_priv(dev);
1328         /* Let the netdevice take a reference on the ppp file. This ensures
1329          * that ppp_destroy_interface() won't run before the device gets
1330          * unregistered.
1331          */
1332         refcount_inc(&ppp->file.refcnt);
1333 
1334         return 0;
1335 }
1336 
1337 static void ppp_dev_uninit(struct net_device *dev)
1338 {
1339         struct ppp *ppp = netdev_priv(dev);
1340         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1341 
1342         ppp_lock(ppp);
1343         ppp->closing = 1;
1344         ppp_unlock(ppp);
1345 
1346         mutex_lock(&pn->all_ppp_mutex);
1347         unit_put(&pn->units_idr, ppp->file.index);
1348         mutex_unlock(&pn->all_ppp_mutex);
1349 
1350         ppp->owner = NULL;
1351 
1352         ppp->file.dead = 1;
1353         wake_up_interruptible(&ppp->file.rwait);
1354 }
1355 
1356 static void ppp_dev_priv_destructor(struct net_device *dev)
1357 {
1358         struct ppp *ppp;
1359 
1360         ppp = netdev_priv(dev);
1361         if (refcount_dec_and_test(&ppp->file.refcnt))
1362                 ppp_destroy_interface(ppp);
1363 }
1364 
1365 static const struct net_device_ops ppp_netdev_ops = {
1366         .ndo_init        = ppp_dev_init,
1367         .ndo_uninit      = ppp_dev_uninit,
1368         .ndo_start_xmit  = ppp_start_xmit,
1369         .ndo_do_ioctl    = ppp_net_ioctl,
1370         .ndo_get_stats64 = ppp_get_stats64,
1371 };
1372 
1373 static struct device_type ppp_type = {
1374         .name = "ppp",
1375 };
1376 
1377 static void ppp_setup(struct net_device *dev)
1378 {
1379         dev->netdev_ops = &ppp_netdev_ops;
1380         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1381 
1382         dev->features |= NETIF_F_LLTX;
1383 
1384         dev->hard_header_len = PPP_HDRLEN;
1385         dev->mtu = PPP_MRU;
1386         dev->addr_len = 0;
1387         dev->tx_queue_len = 3;
1388         dev->type = ARPHRD_PPP;
1389         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1390         dev->priv_destructor = ppp_dev_priv_destructor;
1391         netif_keep_dst(dev);
1392 }
1393 
1394 /*
1395  * Transmit-side routines.
1396  */
1397 
1398 /* Called to do any work queued up on the transmit side that can now be done */
1399 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1400 {
1401         ppp_xmit_lock(ppp);
1402         if (!ppp->closing) {
1403                 ppp_push(ppp);
1404 
1405                 if (skb)
1406                         skb_queue_tail(&ppp->file.xq, skb);
1407                 while (!ppp->xmit_pending &&
1408                        (skb = skb_dequeue(&ppp->file.xq)))
1409                         ppp_send_frame(ppp, skb);
1410                 /* If there's no work left to do, tell the core net
1411                    code that we can accept some more. */
1412                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1413                         netif_wake_queue(ppp->dev);
1414                 else
1415                         netif_stop_queue(ppp->dev);
1416         } else {
1417                 kfree_skb(skb);
1418         }
1419         ppp_xmit_unlock(ppp);
1420 }
1421 
1422 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1423 {
1424         local_bh_disable();
1425 
1426         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1427                 goto err;
1428 
1429         (*this_cpu_ptr(ppp->xmit_recursion))++;
1430         __ppp_xmit_process(ppp, skb);
1431         (*this_cpu_ptr(ppp->xmit_recursion))--;
1432 
1433         local_bh_enable();
1434 
1435         return;
1436 
1437 err:
1438         local_bh_enable();
1439 
1440         kfree_skb(skb);
1441 
1442         if (net_ratelimit())
1443                 netdev_err(ppp->dev, "recursion detected\n");
1444 }
1445 
1446 static inline struct sk_buff *
1447 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1448 {
1449         struct sk_buff *new_skb;
1450         int len;
1451         int new_skb_size = ppp->dev->mtu +
1452                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1453         int compressor_skb_size = ppp->dev->mtu +
1454                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1455         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1456         if (!new_skb) {
1457                 if (net_ratelimit())
1458                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1459                 return NULL;
1460         }
1461         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1462                 skb_reserve(new_skb,
1463                             ppp->dev->hard_header_len - PPP_HDRLEN);
1464 
1465         /* compressor still expects A/C bytes in hdr */
1466         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1467                                    new_skb->data, skb->len + 2,
1468                                    compressor_skb_size);
1469         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1470                 consume_skb(skb);
1471                 skb = new_skb;
1472                 skb_put(skb, len);
1473                 skb_pull(skb, 2);       /* pull off A/C bytes */
1474         } else if (len == 0) {
1475                 /* didn't compress, or CCP not up yet */
1476                 consume_skb(new_skb);
1477                 new_skb = skb;
1478         } else {
1479                 /*
1480                  * (len < 0)
1481                  * MPPE requires that we do not send unencrypted
1482                  * frames.  The compressor will return -1 if we
1483                  * should drop the frame.  We cannot simply test
1484                  * the compress_proto because MPPE and MPPC share
1485                  * the same number.
1486                  */
1487                 if (net_ratelimit())
1488                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1489                 kfree_skb(skb);
1490                 consume_skb(new_skb);
1491                 new_skb = NULL;
1492         }
1493         return new_skb;
1494 }
1495 
1496 /*
1497  * Compress and send a frame.
1498  * The caller should have locked the xmit path,
1499  * and xmit_pending should be 0.
1500  */
1501 static void
1502 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1503 {
1504         int proto = PPP_PROTO(skb);
1505         struct sk_buff *new_skb;
1506         int len;
1507         unsigned char *cp;
1508 
1509         if (proto < 0x8000) {
1510 #ifdef CONFIG_PPP_FILTER
1511                 /* check if we should pass this packet */
1512                 /* the filter instructions are constructed assuming
1513                    a four-byte PPP header on each packet */
1514                 *(u8 *)skb_push(skb, 2) = 1;
1515                 if (ppp->pass_filter &&
1516                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1517                         if (ppp->debug & 1)
1518                                 netdev_printk(KERN_DEBUG, ppp->dev,
1519                                               "PPP: outbound frame "
1520                                               "not passed\n");
1521                         kfree_skb(skb);
1522                         return;
1523                 }
1524                 /* if this packet passes the active filter, record the time */
1525                 if (!(ppp->active_filter &&
1526                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1527                         ppp->last_xmit = jiffies;
1528                 skb_pull(skb, 2);
1529 #else
1530                 /* for data packets, record the time */
1531                 ppp->last_xmit = jiffies;
1532 #endif /* CONFIG_PPP_FILTER */
1533         }
1534 
1535         ++ppp->stats64.tx_packets;
1536         ppp->stats64.tx_bytes += skb->len - 2;
1537 
1538         switch (proto) {
1539         case PPP_IP:
1540                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1541                         break;
1542                 /* try to do VJ TCP header compression */
1543                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1544                                     GFP_ATOMIC);
1545                 if (!new_skb) {
1546                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1547                         goto drop;
1548                 }
1549                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1550                 cp = skb->data + 2;
1551                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1552                                     new_skb->data + 2, &cp,
1553                                     !(ppp->flags & SC_NO_TCP_CCID));
1554                 if (cp == skb->data + 2) {
1555                         /* didn't compress */
1556                         consume_skb(new_skb);
1557                 } else {
1558                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1559                                 proto = PPP_VJC_COMP;
1560                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1561                         } else {
1562                                 proto = PPP_VJC_UNCOMP;
1563                                 cp[0] = skb->data[2];
1564                         }
1565                         consume_skb(skb);
1566                         skb = new_skb;
1567                         cp = skb_put(skb, len + 2);
1568                         cp[0] = 0;
1569                         cp[1] = proto;
1570                 }
1571                 break;
1572 
1573         case PPP_CCP:
1574                 /* peek at outbound CCP frames */
1575                 ppp_ccp_peek(ppp, skb, 0);
1576                 break;
1577         }
1578 
1579         /* try to do packet compression */
1580         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1581             proto != PPP_LCP && proto != PPP_CCP) {
1582                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1583                         if (net_ratelimit())
1584                                 netdev_err(ppp->dev,
1585                                            "ppp: compression required but "
1586                                            "down - pkt dropped.\n");
1587                         goto drop;
1588                 }
1589                 skb = pad_compress_skb(ppp, skb);
1590                 if (!skb)
1591                         goto drop;
1592         }
1593 
1594         /*
1595          * If we are waiting for traffic (demand dialling),
1596          * queue it up for pppd to receive.
1597          */
1598         if (ppp->flags & SC_LOOP_TRAFFIC) {
1599                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1600                         goto drop;
1601                 skb_queue_tail(&ppp->file.rq, skb);
1602                 wake_up_interruptible(&ppp->file.rwait);
1603                 return;
1604         }
1605 
1606         ppp->xmit_pending = skb;
1607         ppp_push(ppp);
1608         return;
1609 
1610  drop:
1611         kfree_skb(skb);
1612         ++ppp->dev->stats.tx_errors;
1613 }
1614 
1615 /*
1616  * Try to send the frame in xmit_pending.
1617  * The caller should have the xmit path locked.
1618  */
1619 static void
1620 ppp_push(struct ppp *ppp)
1621 {
1622         struct list_head *list;
1623         struct channel *pch;
1624         struct sk_buff *skb = ppp->xmit_pending;
1625 
1626         if (!skb)
1627                 return;
1628 
1629         list = &ppp->channels;
1630         if (list_empty(list)) {
1631                 /* nowhere to send the packet, just drop it */
1632                 ppp->xmit_pending = NULL;
1633                 kfree_skb(skb);
1634                 return;
1635         }
1636 
1637         if ((ppp->flags & SC_MULTILINK) == 0) {
1638                 /* not doing multilink: send it down the first channel */
1639                 list = list->next;
1640                 pch = list_entry(list, struct channel, clist);
1641 
1642                 spin_lock(&pch->downl);
1643                 if (pch->chan) {
1644                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1645                                 ppp->xmit_pending = NULL;
1646                 } else {
1647                         /* channel got unregistered */
1648                         kfree_skb(skb);
1649                         ppp->xmit_pending = NULL;
1650                 }
1651                 spin_unlock(&pch->downl);
1652                 return;
1653         }
1654 
1655 #ifdef CONFIG_PPP_MULTILINK
1656         /* Multilink: fragment the packet over as many links
1657            as can take the packet at the moment. */
1658         if (!ppp_mp_explode(ppp, skb))
1659                 return;
1660 #endif /* CONFIG_PPP_MULTILINK */
1661 
1662         ppp->xmit_pending = NULL;
1663         kfree_skb(skb);
1664 }
1665 
1666 #ifdef CONFIG_PPP_MULTILINK
1667 static bool mp_protocol_compress __read_mostly = true;
1668 module_param(mp_protocol_compress, bool, 0644);
1669 MODULE_PARM_DESC(mp_protocol_compress,
1670                  "compress protocol id in multilink fragments");
1671 
1672 /*
1673  * Divide a packet to be transmitted into fragments and
1674  * send them out the individual links.
1675  */
1676 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1677 {
1678         int len, totlen;
1679         int i, bits, hdrlen, mtu;
1680         int flen;
1681         int navail, nfree, nzero;
1682         int nbigger;
1683         int totspeed;
1684         int totfree;
1685         unsigned char *p, *q;
1686         struct list_head *list;
1687         struct channel *pch;
1688         struct sk_buff *frag;
1689         struct ppp_channel *chan;
1690 
1691         totspeed = 0; /*total bitrate of the bundle*/
1692         nfree = 0; /* # channels which have no packet already queued */
1693         navail = 0; /* total # of usable channels (not deregistered) */
1694         nzero = 0; /* number of channels with zero speed associated*/
1695         totfree = 0; /*total # of channels available and
1696                                   *having no queued packets before
1697                                   *starting the fragmentation*/
1698 
1699         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1700         i = 0;
1701         list_for_each_entry(pch, &ppp->channels, clist) {
1702                 if (pch->chan) {
1703                         pch->avail = 1;
1704                         navail++;
1705                         pch->speed = pch->chan->speed;
1706                 } else {
1707                         pch->avail = 0;
1708                 }
1709                 if (pch->avail) {
1710                         if (skb_queue_empty(&pch->file.xq) ||
1711                                 !pch->had_frag) {
1712                                         if (pch->speed == 0)
1713                                                 nzero++;
1714                                         else
1715                                                 totspeed += pch->speed;
1716 
1717                                         pch->avail = 2;
1718                                         ++nfree;
1719                                         ++totfree;
1720                                 }
1721                         if (!pch->had_frag && i < ppp->nxchan)
1722                                 ppp->nxchan = i;
1723                 }
1724                 ++i;
1725         }
1726         /*
1727          * Don't start sending this packet unless at least half of
1728          * the channels are free.  This gives much better TCP
1729          * performance if we have a lot of channels.
1730          */
1731         if (nfree == 0 || nfree < navail / 2)
1732                 return 0; /* can't take now, leave it in xmit_pending */
1733 
1734         /* Do protocol field compression */
1735         p = skb->data;
1736         len = skb->len;
1737         if (*p == 0 && mp_protocol_compress) {
1738                 ++p;
1739                 --len;
1740         }
1741 
1742         totlen = len;
1743         nbigger = len % nfree;
1744 
1745         /* skip to the channel after the one we last used
1746            and start at that one */
1747         list = &ppp->channels;
1748         for (i = 0; i < ppp->nxchan; ++i) {
1749                 list = list->next;
1750                 if (list == &ppp->channels) {
1751                         i = 0;
1752                         break;
1753                 }
1754         }
1755 
1756         /* create a fragment for each channel */
1757         bits = B;
1758         while (len > 0) {
1759                 list = list->next;
1760                 if (list == &ppp->channels) {
1761                         i = 0;
1762                         continue;
1763                 }
1764                 pch = list_entry(list, struct channel, clist);
1765                 ++i;
1766                 if (!pch->avail)
1767                         continue;
1768 
1769                 /*
1770                  * Skip this channel if it has a fragment pending already and
1771                  * we haven't given a fragment to all of the free channels.
1772                  */
1773                 if (pch->avail == 1) {
1774                         if (nfree > 0)
1775                                 continue;
1776                 } else {
1777                         pch->avail = 1;
1778                 }
1779 
1780                 /* check the channel's mtu and whether it is still attached. */
1781                 spin_lock(&pch->downl);
1782                 if (pch->chan == NULL) {
1783                         /* can't use this channel, it's being deregistered */
1784                         if (pch->speed == 0)
1785                                 nzero--;
1786                         else
1787                                 totspeed -= pch->speed;
1788 
1789                         spin_unlock(&pch->downl);
1790                         pch->avail = 0;
1791                         totlen = len;
1792                         totfree--;
1793                         nfree--;
1794                         if (--navail == 0)
1795                                 break;
1796                         continue;
1797                 }
1798 
1799                 /*
1800                 *if the channel speed is not set divide
1801                 *the packet evenly among the free channels;
1802                 *otherwise divide it according to the speed
1803                 *of the channel we are going to transmit on
1804                 */
1805                 flen = len;
1806                 if (nfree > 0) {
1807                         if (pch->speed == 0) {
1808                                 flen = len/nfree;
1809                                 if (nbigger > 0) {
1810                                         flen++;
1811                                         nbigger--;
1812                                 }
1813                         } else {
1814                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1815                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1816                                 if (nbigger > 0) {
1817                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1818                                         nbigger -= ((totfree - nzero)*pch->speed)/
1819                                                         totspeed;
1820                                 }
1821                         }
1822                         nfree--;
1823                 }
1824 
1825                 /*
1826                  *check if we are on the last channel or
1827                  *we exceded the length of the data to
1828                  *fragment
1829                  */
1830                 if ((nfree <= 0) || (flen > len))
1831                         flen = len;
1832                 /*
1833                  *it is not worth to tx on slow channels:
1834                  *in that case from the resulting flen according to the
1835                  *above formula will be equal or less than zero.
1836                  *Skip the channel in this case
1837                  */
1838                 if (flen <= 0) {
1839                         pch->avail = 2;
1840                         spin_unlock(&pch->downl);
1841                         continue;
1842                 }
1843 
1844                 /*
1845                  * hdrlen includes the 2-byte PPP protocol field, but the
1846                  * MTU counts only the payload excluding the protocol field.
1847                  * (RFC1661 Section 2)
1848                  */
1849                 mtu = pch->chan->mtu - (hdrlen - 2);
1850                 if (mtu < 4)
1851                         mtu = 4;
1852                 if (flen > mtu)
1853                         flen = mtu;
1854                 if (flen == len)
1855                         bits |= E;
1856                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1857                 if (!frag)
1858                         goto noskb;
1859                 q = skb_put(frag, flen + hdrlen);
1860 
1861                 /* make the MP header */
1862                 put_unaligned_be16(PPP_MP, q);
1863                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1864                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1865                         q[3] = ppp->nxseq;
1866                 } else {
1867                         q[2] = bits;
1868                         q[3] = ppp->nxseq >> 16;
1869                         q[4] = ppp->nxseq >> 8;
1870                         q[5] = ppp->nxseq;
1871                 }
1872 
1873                 memcpy(q + hdrlen, p, flen);
1874 
1875                 /* try to send it down the channel */
1876                 chan = pch->chan;
1877                 if (!skb_queue_empty(&pch->file.xq) ||
1878                         !chan->ops->start_xmit(chan, frag))
1879                         skb_queue_tail(&pch->file.xq, frag);
1880                 pch->had_frag = 1;
1881                 p += flen;
1882                 len -= flen;
1883                 ++ppp->nxseq;
1884                 bits = 0;
1885                 spin_unlock(&pch->downl);
1886         }
1887         ppp->nxchan = i;
1888 
1889         return 1;
1890 
1891  noskb:
1892         spin_unlock(&pch->downl);
1893         if (ppp->debug & 1)
1894                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1895         ++ppp->dev->stats.tx_errors;
1896         ++ppp->nxseq;
1897         return 1;       /* abandon the frame */
1898 }
1899 #endif /* CONFIG_PPP_MULTILINK */
1900 
1901 /* Try to send data out on a channel */
1902 static void __ppp_channel_push(struct channel *pch)
1903 {
1904         struct sk_buff *skb;
1905         struct ppp *ppp;
1906 
1907         spin_lock(&pch->downl);
1908         if (pch->chan) {
1909                 while (!skb_queue_empty(&pch->file.xq)) {
1910                         skb = skb_dequeue(&pch->file.xq);
1911                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1912                                 /* put the packet back and try again later */
1913                                 skb_queue_head(&pch->file.xq, skb);
1914                                 break;
1915                         }
1916                 }
1917         } else {
1918                 /* channel got deregistered */
1919                 skb_queue_purge(&pch->file.xq);
1920         }
1921         spin_unlock(&pch->downl);
1922         /* see if there is anything from the attached unit to be sent */
1923         if (skb_queue_empty(&pch->file.xq)) {
1924                 ppp = pch->ppp;
1925                 if (ppp)
1926                         __ppp_xmit_process(ppp, NULL);
1927         }
1928 }
1929 
1930 static void ppp_channel_push(struct channel *pch)
1931 {
1932         read_lock_bh(&pch->upl);
1933         if (pch->ppp) {
1934                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
1935                 __ppp_channel_push(pch);
1936                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
1937         } else {
1938                 __ppp_channel_push(pch);
1939         }
1940         read_unlock_bh(&pch->upl);
1941 }
1942 
1943 /*
1944  * Receive-side routines.
1945  */
1946 
1947 struct ppp_mp_skb_parm {
1948         u32             sequence;
1949         u8              BEbits;
1950 };
1951 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1952 
1953 static inline void
1954 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1955 {
1956         ppp_recv_lock(ppp);
1957         if (!ppp->closing)
1958                 ppp_receive_frame(ppp, skb, pch);
1959         else
1960                 kfree_skb(skb);
1961         ppp_recv_unlock(ppp);
1962 }
1963 
1964 /**
1965  * __ppp_decompress_proto - Decompress protocol field, slim version.
1966  * @skb: Socket buffer where protocol field should be decompressed. It must have
1967  *       at least 1 byte of head room and 1 byte of linear data. First byte of
1968  *       data must be a protocol field byte.
1969  *
1970  * Decompress protocol field in PPP header if it's compressed, e.g. when
1971  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
1972  * length are done in this function.
1973  */
1974 static void __ppp_decompress_proto(struct sk_buff *skb)
1975 {
1976         if (skb->data[0] & 0x01)
1977                 *(u8 *)skb_push(skb, 1) = 0x00;
1978 }
1979 
1980 /**
1981  * ppp_decompress_proto - Check skb data room and decompress protocol field.
1982  * @skb: Socket buffer where protocol field should be decompressed. First byte
1983  *       of data must be a protocol field byte.
1984  *
1985  * Decompress protocol field in PPP header if it's compressed, e.g. when
1986  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
1987  * sure that skb data room is sufficient for Protocol field, before and after
1988  * decompression.
1989  *
1990  * Return: true - decompressed successfully, false - not enough room in skb.
1991  */
1992 static bool ppp_decompress_proto(struct sk_buff *skb)
1993 {
1994         /* At least one byte should be present (if protocol is compressed) */
1995         if (!pskb_may_pull(skb, 1))
1996                 return false;
1997 
1998         __ppp_decompress_proto(skb);
1999 
2000         /* Protocol field should occupy 2 bytes when not compressed */
2001         return pskb_may_pull(skb, 2);
2002 }
2003 
2004 void
2005 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2006 {
2007         struct channel *pch = chan->ppp;
2008         int proto;
2009 
2010         if (!pch) {
2011                 kfree_skb(skb);
2012                 return;
2013         }
2014 
2015         read_lock_bh(&pch->upl);
2016         if (!ppp_decompress_proto(skb)) {
2017                 kfree_skb(skb);
2018                 if (pch->ppp) {
2019                         ++pch->ppp->dev->stats.rx_length_errors;
2020                         ppp_receive_error(pch->ppp);
2021                 }
2022                 goto done;
2023         }
2024 
2025         proto = PPP_PROTO(skb);
2026         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2027                 /* put it on the channel queue */
2028                 skb_queue_tail(&pch->file.rq, skb);
2029                 /* drop old frames if queue too long */
2030                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2031                        (skb = skb_dequeue(&pch->file.rq)))
2032                         kfree_skb(skb);
2033                 wake_up_interruptible(&pch->file.rwait);
2034         } else {
2035                 ppp_do_recv(pch->ppp, skb, pch);
2036         }
2037 
2038 done:
2039         read_unlock_bh(&pch->upl);
2040 }
2041 
2042 /* Put a 0-length skb in the receive queue as an error indication */
2043 void
2044 ppp_input_error(struct ppp_channel *chan, int code)
2045 {
2046         struct channel *pch = chan->ppp;
2047         struct sk_buff *skb;
2048 
2049         if (!pch)
2050                 return;
2051 
2052         read_lock_bh(&pch->upl);
2053         if (pch->ppp) {
2054                 skb = alloc_skb(0, GFP_ATOMIC);
2055                 if (skb) {
2056                         skb->len = 0;           /* probably unnecessary */
2057                         skb->cb[0] = code;
2058                         ppp_do_recv(pch->ppp, skb, pch);
2059                 }
2060         }
2061         read_unlock_bh(&pch->upl);
2062 }
2063 
2064 /*
2065  * We come in here to process a received frame.
2066  * The receive side of the ppp unit is locked.
2067  */
2068 static void
2069 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2070 {
2071         /* note: a 0-length skb is used as an error indication */
2072         if (skb->len > 0) {
2073                 skb_checksum_complete_unset(skb);
2074 #ifdef CONFIG_PPP_MULTILINK
2075                 /* XXX do channel-level decompression here */
2076                 if (PPP_PROTO(skb) == PPP_MP)
2077                         ppp_receive_mp_frame(ppp, skb, pch);
2078                 else
2079 #endif /* CONFIG_PPP_MULTILINK */
2080                         ppp_receive_nonmp_frame(ppp, skb);
2081         } else {
2082                 kfree_skb(skb);
2083                 ppp_receive_error(ppp);
2084         }
2085 }
2086 
2087 static void
2088 ppp_receive_error(struct ppp *ppp)
2089 {
2090         ++ppp->dev->stats.rx_errors;
2091         if (ppp->vj)
2092                 slhc_toss(ppp->vj);
2093 }
2094 
2095 static void
2096 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2097 {
2098         struct sk_buff *ns;
2099         int proto, len, npi;
2100 
2101         /*
2102          * Decompress the frame, if compressed.
2103          * Note that some decompressors need to see uncompressed frames
2104          * that come in as well as compressed frames.
2105          */
2106         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2107             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2108                 skb = ppp_decompress_frame(ppp, skb);
2109 
2110         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2111                 goto err;
2112 
2113         /* At this point the "Protocol" field MUST be decompressed, either in
2114          * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2115          */
2116         proto = PPP_PROTO(skb);
2117         switch (proto) {
2118         case PPP_VJC_COMP:
2119                 /* decompress VJ compressed packets */
2120                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2121                         goto err;
2122 
2123                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2124                         /* copy to a new sk_buff with more tailroom */
2125                         ns = dev_alloc_skb(skb->len + 128);
2126                         if (!ns) {
2127                                 netdev_err(ppp->dev, "PPP: no memory "
2128                                            "(VJ decomp)\n");
2129                                 goto err;
2130                         }
2131                         skb_reserve(ns, 2);
2132                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2133                         consume_skb(skb);
2134                         skb = ns;
2135                 }
2136                 else
2137                         skb->ip_summed = CHECKSUM_NONE;
2138 
2139                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2140                 if (len <= 0) {
2141                         netdev_printk(KERN_DEBUG, ppp->dev,
2142                                       "PPP: VJ decompression error\n");
2143                         goto err;
2144                 }
2145                 len += 2;
2146                 if (len > skb->len)
2147                         skb_put(skb, len - skb->len);
2148                 else if (len < skb->len)
2149                         skb_trim(skb, len);
2150                 proto = PPP_IP;
2151                 break;
2152 
2153         case PPP_VJC_UNCOMP:
2154                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2155                         goto err;
2156 
2157                 /* Until we fix the decompressor need to make sure
2158                  * data portion is linear.
2159                  */
2160                 if (!pskb_may_pull(skb, skb->len))
2161                         goto err;
2162 
2163                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2164                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2165                         goto err;
2166                 }
2167                 proto = PPP_IP;
2168                 break;
2169 
2170         case PPP_CCP:
2171                 ppp_ccp_peek(ppp, skb, 1);
2172                 break;
2173         }
2174 
2175         ++ppp->stats64.rx_packets;
2176         ppp->stats64.rx_bytes += skb->len - 2;
2177 
2178         npi = proto_to_npindex(proto);
2179         if (npi < 0) {
2180                 /* control or unknown frame - pass it to pppd */
2181                 skb_queue_tail(&ppp->file.rq, skb);
2182                 /* limit queue length by dropping old frames */
2183                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2184                        (skb = skb_dequeue(&ppp->file.rq)))
2185                         kfree_skb(skb);
2186                 /* wake up any process polling or blocking on read */
2187                 wake_up_interruptible(&ppp->file.rwait);
2188 
2189         } else {
2190                 /* network protocol frame - give it to the kernel */
2191 
2192 #ifdef CONFIG_PPP_FILTER
2193                 /* check if the packet passes the pass and active filters */
2194                 /* the filter instructions are constructed assuming
2195                    a four-byte PPP header on each packet */
2196                 if (ppp->pass_filter || ppp->active_filter) {
2197                         if (skb_unclone(skb, GFP_ATOMIC))
2198                                 goto err;
2199 
2200                         *(u8 *)skb_push(skb, 2) = 0;
2201                         if (ppp->pass_filter &&
2202                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2203                                 if (ppp->debug & 1)
2204                                         netdev_printk(KERN_DEBUG, ppp->dev,
2205                                                       "PPP: inbound frame "
2206                                                       "not passed\n");
2207                                 kfree_skb(skb);
2208                                 return;
2209                         }
2210                         if (!(ppp->active_filter &&
2211                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2212                                 ppp->last_recv = jiffies;
2213                         __skb_pull(skb, 2);
2214                 } else
2215 #endif /* CONFIG_PPP_FILTER */
2216                         ppp->last_recv = jiffies;
2217 
2218                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2219                     ppp->npmode[npi] != NPMODE_PASS) {
2220                         kfree_skb(skb);
2221                 } else {
2222                         /* chop off protocol */
2223                         skb_pull_rcsum(skb, 2);
2224                         skb->dev = ppp->dev;
2225                         skb->protocol = htons(npindex_to_ethertype[npi]);
2226                         skb_reset_mac_header(skb);
2227                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2228                                                       dev_net(ppp->dev)));
2229                         netif_rx(skb);
2230                 }
2231         }
2232         return;
2233 
2234  err:
2235         kfree_skb(skb);
2236         ppp_receive_error(ppp);
2237 }
2238 
2239 static struct sk_buff *
2240 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2241 {
2242         int proto = PPP_PROTO(skb);
2243         struct sk_buff *ns;
2244         int len;
2245 
2246         /* Until we fix all the decompressor's need to make sure
2247          * data portion is linear.
2248          */
2249         if (!pskb_may_pull(skb, skb->len))
2250                 goto err;
2251 
2252         if (proto == PPP_COMP) {
2253                 int obuff_size;
2254 
2255                 switch(ppp->rcomp->compress_proto) {
2256                 case CI_MPPE:
2257                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2258                         break;
2259                 default:
2260                         obuff_size = ppp->mru + PPP_HDRLEN;
2261                         break;
2262                 }
2263 
2264                 ns = dev_alloc_skb(obuff_size);
2265                 if (!ns) {
2266                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2267                                    "no memory\n");
2268                         goto err;
2269                 }
2270                 /* the decompressor still expects the A/C bytes in the hdr */
2271                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2272                                 skb->len + 2, ns->data, obuff_size);
2273                 if (len < 0) {
2274                         /* Pass the compressed frame to pppd as an
2275                            error indication. */
2276                         if (len == DECOMP_FATALERROR)
2277                                 ppp->rstate |= SC_DC_FERROR;
2278                         kfree_skb(ns);
2279                         goto err;
2280                 }
2281 
2282                 consume_skb(skb);
2283                 skb = ns;
2284                 skb_put(skb, len);
2285                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2286 
2287                 /* Don't call __ppp_decompress_proto() here, but instead rely on
2288                  * corresponding algo (mppe/bsd/deflate) to decompress it.
2289                  */
2290         } else {
2291                 /* Uncompressed frame - pass to decompressor so it
2292                    can update its dictionary if necessary. */
2293                 if (ppp->rcomp->incomp)
2294                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2295                                            skb->len + 2);
2296         }
2297 
2298         return skb;
2299 
2300  err:
2301         ppp->rstate |= SC_DC_ERROR;
2302         ppp_receive_error(ppp);
2303         return skb;
2304 }
2305 
2306 #ifdef CONFIG_PPP_MULTILINK
2307 /*
2308  * Receive a multilink frame.
2309  * We put it on the reconstruction queue and then pull off
2310  * as many completed frames as we can.
2311  */
2312 static void
2313 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2314 {
2315         u32 mask, seq;
2316         struct channel *ch;
2317         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2318 
2319         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2320                 goto err;               /* no good, throw it away */
2321 
2322         /* Decode sequence number and begin/end bits */
2323         if (ppp->flags & SC_MP_SHORTSEQ) {
2324                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2325                 mask = 0xfff;
2326         } else {
2327                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2328                 mask = 0xffffff;
2329         }
2330         PPP_MP_CB(skb)->BEbits = skb->data[2];
2331         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2332 
2333         /*
2334          * Do protocol ID decompression on the first fragment of each packet.
2335          * We have to do that here, because ppp_receive_nonmp_frame() expects
2336          * decompressed protocol field.
2337          */
2338         if (PPP_MP_CB(skb)->BEbits & B)
2339                 __ppp_decompress_proto(skb);
2340 
2341         /*
2342          * Expand sequence number to 32 bits, making it as close
2343          * as possible to ppp->minseq.
2344          */
2345         seq |= ppp->minseq & ~mask;
2346         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2347                 seq += mask + 1;
2348         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2349                 seq -= mask + 1;        /* should never happen */
2350         PPP_MP_CB(skb)->sequence = seq;
2351         pch->lastseq = seq;
2352 
2353         /*
2354          * If this packet comes before the next one we were expecting,
2355          * drop it.
2356          */
2357         if (seq_before(seq, ppp->nextseq)) {
2358                 kfree_skb(skb);
2359                 ++ppp->dev->stats.rx_dropped;
2360                 ppp_receive_error(ppp);
2361                 return;
2362         }
2363 
2364         /*
2365          * Reevaluate minseq, the minimum over all channels of the
2366          * last sequence number received on each channel.  Because of
2367          * the increasing sequence number rule, we know that any fragment
2368          * before `minseq' which hasn't arrived is never going to arrive.
2369          * The list of channels can't change because we have the receive
2370          * side of the ppp unit locked.
2371          */
2372         list_for_each_entry(ch, &ppp->channels, clist) {
2373                 if (seq_before(ch->lastseq, seq))
2374                         seq = ch->lastseq;
2375         }
2376         if (seq_before(ppp->minseq, seq))
2377                 ppp->minseq = seq;
2378 
2379         /* Put the fragment on the reconstruction queue */
2380         ppp_mp_insert(ppp, skb);
2381 
2382         /* If the queue is getting long, don't wait any longer for packets
2383            before the start of the queue. */
2384         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2385                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2386                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2387                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2388         }
2389 
2390         /* Pull completed packets off the queue and receive them. */
2391         while ((skb = ppp_mp_reconstruct(ppp))) {
2392                 if (pskb_may_pull(skb, 2))
2393                         ppp_receive_nonmp_frame(ppp, skb);
2394                 else {
2395                         ++ppp->dev->stats.rx_length_errors;
2396                         kfree_skb(skb);
2397                         ppp_receive_error(ppp);
2398                 }
2399         }
2400 
2401         return;
2402 
2403  err:
2404         kfree_skb(skb);
2405         ppp_receive_error(ppp);
2406 }
2407 
2408 /*
2409  * Insert a fragment on the MP reconstruction queue.
2410  * The queue is ordered by increasing sequence number.
2411  */
2412 static void
2413 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2414 {
2415         struct sk_buff *p;
2416         struct sk_buff_head *list = &ppp->mrq;
2417         u32 seq = PPP_MP_CB(skb)->sequence;
2418 
2419         /* N.B. we don't need to lock the list lock because we have the
2420            ppp unit receive-side lock. */
2421         skb_queue_walk(list, p) {
2422                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2423                         break;
2424         }
2425         __skb_queue_before(list, p, skb);
2426 }
2427 
2428 /*
2429  * Reconstruct a packet from the MP fragment queue.
2430  * We go through increasing sequence numbers until we find a
2431  * complete packet, or we get to the sequence number for a fragment
2432  * which hasn't arrived but might still do so.
2433  */
2434 static struct sk_buff *
2435 ppp_mp_reconstruct(struct ppp *ppp)
2436 {
2437         u32 seq = ppp->nextseq;
2438         u32 minseq = ppp->minseq;
2439         struct sk_buff_head *list = &ppp->mrq;
2440         struct sk_buff *p, *tmp;
2441         struct sk_buff *head, *tail;
2442         struct sk_buff *skb = NULL;
2443         int lost = 0, len = 0;
2444 
2445         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2446                 return NULL;
2447         head = __skb_peek(list);
2448         tail = NULL;
2449         skb_queue_walk_safe(list, p, tmp) {
2450         again:
2451                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2452                         /* this can't happen, anyway ignore the skb */
2453                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2454                                    "seq %u < %u\n",
2455                                    PPP_MP_CB(p)->sequence, seq);
2456                         __skb_unlink(p, list);
2457                         kfree_skb(p);
2458                         continue;
2459                 }
2460                 if (PPP_MP_CB(p)->sequence != seq) {
2461                         u32 oldseq;
2462                         /* Fragment `seq' is missing.  If it is after
2463                            minseq, it might arrive later, so stop here. */
2464                         if (seq_after(seq, minseq))
2465                                 break;
2466                         /* Fragment `seq' is lost, keep going. */
2467                         lost = 1;
2468                         oldseq = seq;
2469                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2470                                 minseq + 1: PPP_MP_CB(p)->sequence;
2471 
2472                         if (ppp->debug & 1)
2473                                 netdev_printk(KERN_DEBUG, ppp->dev,
2474                                               "lost frag %u..%u\n",
2475                                               oldseq, seq-1);
2476 
2477                         goto again;
2478                 }
2479 
2480                 /*
2481                  * At this point we know that all the fragments from
2482                  * ppp->nextseq to seq are either present or lost.
2483                  * Also, there are no complete packets in the queue
2484                  * that have no missing fragments and end before this
2485                  * fragment.
2486                  */
2487 
2488                 /* B bit set indicates this fragment starts a packet */
2489                 if (PPP_MP_CB(p)->BEbits & B) {
2490                         head = p;
2491                         lost = 0;
2492                         len = 0;
2493                 }
2494 
2495                 len += p->len;
2496 
2497                 /* Got a complete packet yet? */
2498                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2499                     (PPP_MP_CB(head)->BEbits & B)) {
2500                         if (len > ppp->mrru + 2) {
2501                                 ++ppp->dev->stats.rx_length_errors;
2502                                 netdev_printk(KERN_DEBUG, ppp->dev,
2503                                               "PPP: reconstructed packet"
2504                                               " is too long (%d)\n", len);
2505                         } else {
2506                                 tail = p;
2507                                 break;
2508                         }
2509                         ppp->nextseq = seq + 1;
2510                 }
2511 
2512                 /*
2513                  * If this is the ending fragment of a packet,
2514                  * and we haven't found a complete valid packet yet,
2515                  * we can discard up to and including this fragment.
2516                  */
2517                 if (PPP_MP_CB(p)->BEbits & E) {
2518                         struct sk_buff *tmp2;
2519 
2520                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2521                                 if (ppp->debug & 1)
2522                                         netdev_printk(KERN_DEBUG, ppp->dev,
2523                                                       "discarding frag %u\n",
2524                                                       PPP_MP_CB(p)->sequence);
2525                                 __skb_unlink(p, list);
2526                                 kfree_skb(p);
2527                         }
2528                         head = skb_peek(list);
2529                         if (!head)
2530                                 break;
2531                 }
2532                 ++seq;
2533         }
2534 
2535         /* If we have a complete packet, copy it all into one skb. */
2536         if (tail != NULL) {
2537                 /* If we have discarded any fragments,
2538                    signal a receive error. */
2539                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2540                         skb_queue_walk_safe(list, p, tmp) {
2541                                 if (p == head)
2542                                         break;
2543                                 if (ppp->debug & 1)
2544                                         netdev_printk(KERN_DEBUG, ppp->dev,
2545                                                       "discarding frag %u\n",
2546                                                       PPP_MP_CB(p)->sequence);
2547                                 __skb_unlink(p, list);
2548                                 kfree_skb(p);
2549                         }
2550 
2551                         if (ppp->debug & 1)
2552                                 netdev_printk(KERN_DEBUG, ppp->dev,
2553                                               "  missed pkts %u..%u\n",
2554                                               ppp->nextseq,
2555                                               PPP_MP_CB(head)->sequence-1);
2556                         ++ppp->dev->stats.rx_dropped;
2557                         ppp_receive_error(ppp);
2558                 }
2559 
2560                 skb = head;
2561                 if (head != tail) {
2562                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2563                         p = skb_queue_next(list, head);
2564                         __skb_unlink(skb, list);
2565                         skb_queue_walk_from_safe(list, p, tmp) {
2566                                 __skb_unlink(p, list);
2567                                 *fragpp = p;
2568                                 p->next = NULL;
2569                                 fragpp = &p->next;
2570 
2571                                 skb->len += p->len;
2572                                 skb->data_len += p->len;
2573                                 skb->truesize += p->truesize;
2574 
2575                                 if (p == tail)
2576                                         break;
2577                         }
2578                 } else {
2579                         __skb_unlink(skb, list);
2580                 }
2581 
2582                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2583         }
2584 
2585         return skb;
2586 }
2587 #endif /* CONFIG_PPP_MULTILINK */
2588 
2589 /*
2590  * Channel interface.
2591  */
2592 
2593 /* Create a new, unattached ppp channel. */
2594 int ppp_register_channel(struct ppp_channel *chan)
2595 {
2596         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2597 }
2598 
2599 /* Create a new, unattached ppp channel for specified net. */
2600 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2601 {
2602         struct channel *pch;
2603         struct ppp_net *pn;
2604 
2605         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2606         if (!pch)
2607                 return -ENOMEM;
2608 
2609         pn = ppp_pernet(net);
2610 
2611         pch->ppp = NULL;
2612         pch->chan = chan;
2613         pch->chan_net = get_net(net);
2614         chan->ppp = pch;
2615         init_ppp_file(&pch->file, CHANNEL);
2616         pch->file.hdrlen = chan->hdrlen;
2617 #ifdef CONFIG_PPP_MULTILINK
2618         pch->lastseq = -1;
2619 #endif /* CONFIG_PPP_MULTILINK */
2620         init_rwsem(&pch->chan_sem);
2621         spin_lock_init(&pch->downl);
2622         rwlock_init(&pch->upl);
2623 
2624         spin_lock_bh(&pn->all_channels_lock);
2625         pch->file.index = ++pn->last_channel_index;
2626         list_add(&pch->list, &pn->new_channels);
2627         atomic_inc(&channel_count);
2628         spin_unlock_bh(&pn->all_channels_lock);
2629 
2630         return 0;
2631 }
2632 
2633 /*
2634  * Return the index of a channel.
2635  */
2636 int ppp_channel_index(struct ppp_channel *chan)
2637 {
2638         struct channel *pch = chan->ppp;
2639 
2640         if (pch)
2641                 return pch->file.index;
2642         return -1;
2643 }
2644 
2645 /*
2646  * Return the PPP unit number to which a channel is connected.
2647  */
2648 int ppp_unit_number(struct ppp_channel *chan)
2649 {
2650         struct channel *pch = chan->ppp;
2651         int unit = -1;
2652 
2653         if (pch) {
2654                 read_lock_bh(&pch->upl);
2655                 if (pch->ppp)
2656                         unit = pch->ppp->file.index;
2657                 read_unlock_bh(&pch->upl);
2658         }
2659         return unit;
2660 }
2661 
2662 /*
2663  * Return the PPP device interface name of a channel.
2664  */
2665 char *ppp_dev_name(struct ppp_channel *chan)
2666 {
2667         struct channel *pch = chan->ppp;
2668         char *name = NULL;
2669 
2670         if (pch) {
2671                 read_lock_bh(&pch->upl);
2672                 if (pch->ppp && pch->ppp->dev)
2673                         name = pch->ppp->dev->name;
2674                 read_unlock_bh(&pch->upl);
2675         }
2676         return name;
2677 }
2678 
2679 
2680 /*
2681  * Disconnect a channel from the generic layer.
2682  * This must be called in process context.
2683  */
2684 void
2685 ppp_unregister_channel(struct ppp_channel *chan)
2686 {
2687         struct channel *pch = chan->ppp;
2688         struct ppp_net *pn;
2689 
2690         if (!pch)
2691                 return;         /* should never happen */
2692 
2693         chan->ppp = NULL;
2694 
2695         /*
2696          * This ensures that we have returned from any calls into the
2697          * the channel's start_xmit or ioctl routine before we proceed.
2698          */
2699         down_write(&pch->chan_sem);
2700         spin_lock_bh(&pch->downl);
2701         pch->chan = NULL;
2702         spin_unlock_bh(&pch->downl);
2703         up_write(&pch->chan_sem);
2704         ppp_disconnect_channel(pch);
2705 
2706         pn = ppp_pernet(pch->chan_net);
2707         spin_lock_bh(&pn->all_channels_lock);
2708         list_del(&pch->list);
2709         spin_unlock_bh(&pn->all_channels_lock);
2710 
2711         pch->file.dead = 1;
2712         wake_up_interruptible(&pch->file.rwait);
2713         if (refcount_dec_and_test(&pch->file.refcnt))
2714                 ppp_destroy_channel(pch);
2715 }
2716 
2717 /*
2718  * Callback from a channel when it can accept more to transmit.
2719  * This should be called at BH/softirq level, not interrupt level.
2720  */
2721 void
2722 ppp_output_wakeup(struct ppp_channel *chan)
2723 {
2724         struct channel *pch = chan->ppp;
2725 
2726         if (!pch)
2727                 return;
2728         ppp_channel_push(pch);
2729 }
2730 
2731 /*
2732  * Compression control.
2733  */
2734 
2735 /* Process the PPPIOCSCOMPRESS ioctl. */
2736 static int
2737 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2738 {
2739         int err;
2740         struct compressor *cp, *ocomp;
2741         struct ppp_option_data data;
2742         void *state, *ostate;
2743         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2744 
2745         err = -EFAULT;
2746         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2747                 goto out;
2748         if (data.length > CCP_MAX_OPTION_LENGTH)
2749                 goto out;
2750         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2751                 goto out;
2752 
2753         err = -EINVAL;
2754         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2755                 goto out;
2756 
2757         cp = try_then_request_module(
2758                 find_compressor(ccp_option[0]),
2759                 "ppp-compress-%d", ccp_option[0]);
2760         if (!cp)
2761                 goto out;
2762 
2763         err = -ENOBUFS;
2764         if (data.transmit) {
2765                 state = cp->comp_alloc(ccp_option, data.length);
2766                 if (state) {
2767                         ppp_xmit_lock(ppp);
2768                         ppp->xstate &= ~SC_COMP_RUN;
2769                         ocomp = ppp->xcomp;
2770                         ostate = ppp->xc_state;
2771                         ppp->xcomp = cp;
2772                         ppp->xc_state = state;
2773                         ppp_xmit_unlock(ppp);
2774                         if (ostate) {
2775                                 ocomp->comp_free(ostate);
2776                                 module_put(ocomp->owner);
2777                         }
2778                         err = 0;
2779                 } else
2780                         module_put(cp->owner);
2781 
2782         } else {
2783                 state = cp->decomp_alloc(ccp_option, data.length);
2784                 if (state) {
2785                         ppp_recv_lock(ppp);
2786                         ppp->rstate &= ~SC_DECOMP_RUN;
2787                         ocomp = ppp->rcomp;
2788                         ostate = ppp->rc_state;
2789                         ppp->rcomp = cp;
2790                         ppp->rc_state = state;
2791                         ppp_recv_unlock(ppp);
2792                         if (ostate) {
2793                                 ocomp->decomp_free(ostate);
2794                                 module_put(ocomp->owner);
2795                         }
2796                         err = 0;
2797                 } else
2798                         module_put(cp->owner);
2799         }
2800 
2801  out:
2802         return err;
2803 }
2804 
2805 /*
2806  * Look at a CCP packet and update our state accordingly.
2807  * We assume the caller has the xmit or recv path locked.
2808  */
2809 static void
2810 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2811 {
2812         unsigned char *dp;
2813         int len;
2814 
2815         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2816                 return; /* no header */
2817         dp = skb->data + 2;
2818 
2819         switch (CCP_CODE(dp)) {
2820         case CCP_CONFREQ:
2821 
2822                 /* A ConfReq starts negotiation of compression
2823                  * in one direction of transmission,
2824                  * and hence brings it down...but which way?
2825                  *
2826                  * Remember:
2827                  * A ConfReq indicates what the sender would like to receive
2828                  */
2829                 if(inbound)
2830                         /* He is proposing what I should send */
2831                         ppp->xstate &= ~SC_COMP_RUN;
2832                 else
2833                         /* I am proposing to what he should send */
2834                         ppp->rstate &= ~SC_DECOMP_RUN;
2835 
2836                 break;
2837 
2838         case CCP_TERMREQ:
2839         case CCP_TERMACK:
2840                 /*
2841                  * CCP is going down, both directions of transmission
2842                  */
2843                 ppp->rstate &= ~SC_DECOMP_RUN;
2844                 ppp->xstate &= ~SC_COMP_RUN;
2845                 break;
2846 
2847         case CCP_CONFACK:
2848                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2849                         break;
2850                 len = CCP_LENGTH(dp);
2851                 if (!pskb_may_pull(skb, len + 2))
2852                         return;         /* too short */
2853                 dp += CCP_HDRLEN;
2854                 len -= CCP_HDRLEN;
2855                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2856                         break;
2857                 if (inbound) {
2858                         /* we will start receiving compressed packets */
2859                         if (!ppp->rc_state)
2860                                 break;
2861                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2862                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2863                                 ppp->rstate |= SC_DECOMP_RUN;
2864                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2865                         }
2866                 } else {
2867                         /* we will soon start sending compressed packets */
2868                         if (!ppp->xc_state)
2869                                 break;
2870                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2871                                         ppp->file.index, 0, ppp->debug))
2872                                 ppp->xstate |= SC_COMP_RUN;
2873                 }
2874                 break;
2875 
2876         case CCP_RESETACK:
2877                 /* reset the [de]compressor */
2878                 if ((ppp->flags & SC_CCP_UP) == 0)
2879                         break;
2880                 if (inbound) {
2881                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2882                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2883                                 ppp->rstate &= ~SC_DC_ERROR;
2884                         }
2885                 } else {
2886                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2887                                 ppp->xcomp->comp_reset(ppp->xc_state);
2888                 }
2889                 break;
2890         }
2891 }
2892 
2893 /* Free up compression resources. */
2894 static void
2895 ppp_ccp_closed(struct ppp *ppp)
2896 {
2897         void *xstate, *rstate;
2898         struct compressor *xcomp, *rcomp;
2899 
2900         ppp_lock(ppp);
2901         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2902         ppp->xstate = 0;
2903         xcomp = ppp->xcomp;
2904         xstate = ppp->xc_state;
2905         ppp->xc_state = NULL;
2906         ppp->rstate = 0;
2907         rcomp = ppp->rcomp;
2908         rstate = ppp->rc_state;
2909         ppp->rc_state = NULL;
2910         ppp_unlock(ppp);
2911 
2912         if (xstate) {
2913                 xcomp->comp_free(xstate);
2914                 module_put(xcomp->owner);
2915         }
2916         if (rstate) {
2917                 rcomp->decomp_free(rstate);
2918                 module_put(rcomp->owner);
2919         }
2920 }
2921 
2922 /* List of compressors. */
2923 static LIST_HEAD(compressor_list);
2924 static DEFINE_SPINLOCK(compressor_list_lock);
2925 
2926 struct compressor_entry {
2927         struct list_head list;
2928         struct compressor *comp;
2929 };
2930 
2931 static struct compressor_entry *
2932 find_comp_entry(int proto)
2933 {
2934         struct compressor_entry *ce;
2935 
2936         list_for_each_entry(ce, &compressor_list, list) {
2937                 if (ce->comp->compress_proto == proto)
2938                         return ce;
2939         }
2940         return NULL;
2941 }
2942 
2943 /* Register a compressor */
2944 int
2945 ppp_register_compressor(struct compressor *cp)
2946 {
2947         struct compressor_entry *ce;
2948         int ret;
2949         spin_lock(&compressor_list_lock);
2950         ret = -EEXIST;
2951         if (find_comp_entry(cp->compress_proto))
2952                 goto out;
2953         ret = -ENOMEM;
2954         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2955         if (!ce)
2956                 goto out;
2957         ret = 0;
2958         ce->comp = cp;
2959         list_add(&ce->list, &compressor_list);
2960  out:
2961         spin_unlock(&compressor_list_lock);
2962         return ret;
2963 }
2964 
2965 /* Unregister a compressor */
2966 void
2967 ppp_unregister_compressor(struct compressor *cp)
2968 {
2969         struct compressor_entry *ce;
2970 
2971         spin_lock(&compressor_list_lock);
2972         ce = find_comp_entry(cp->compress_proto);
2973         if (ce && ce->comp == cp) {
2974                 list_del(&ce->list);
2975                 kfree(ce);
2976         }
2977         spin_unlock(&compressor_list_lock);
2978 }
2979 
2980 /* Find a compressor. */
2981 static struct compressor *
2982 find_compressor(int type)
2983 {
2984         struct compressor_entry *ce;
2985         struct compressor *cp = NULL;
2986 
2987         spin_lock(&compressor_list_lock);
2988         ce = find_comp_entry(type);
2989         if (ce) {
2990                 cp = ce->comp;
2991                 if (!try_module_get(cp->owner))
2992                         cp = NULL;
2993         }
2994         spin_unlock(&compressor_list_lock);
2995         return cp;
2996 }
2997 
2998 /*
2999  * Miscelleneous stuff.
3000  */
3001 
3002 static void
3003 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3004 {
3005         struct slcompress *vj = ppp->vj;
3006 
3007         memset(st, 0, sizeof(*st));
3008         st->p.ppp_ipackets = ppp->stats64.rx_packets;
3009         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3010         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3011         st->p.ppp_opackets = ppp->stats64.tx_packets;
3012         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3013         st->p.ppp_obytes = ppp->stats64.tx_bytes;
3014         if (!vj)
3015                 return;
3016         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3017         st->vj.vjs_compressed = vj->sls_o_compressed;
3018         st->vj.vjs_searches = vj->sls_o_searches;
3019         st->vj.vjs_misses = vj->sls_o_misses;
3020         st->vj.vjs_errorin = vj->sls_i_error;
3021         st->vj.vjs_tossed = vj->sls_i_tossed;
3022         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3023         st->vj.vjs_compressedin = vj->sls_i_compressed;
3024 }
3025 
3026 /*
3027  * Stuff for handling the lists of ppp units and channels
3028  * and for initialization.
3029  */
3030 
3031 /*
3032  * Create a new ppp interface unit.  Fails if it can't allocate memory
3033  * or if there is already a unit with the requested number.
3034  * unit == -1 means allocate a new number.
3035  */
3036 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3037 {
3038         struct ppp_config conf = {
3039                 .file = file,
3040                 .unit = *unit,
3041                 .ifname_is_set = false,
3042         };
3043         struct net_device *dev;
3044         struct ppp *ppp;
3045         int err;
3046 
3047         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3048         if (!dev) {
3049                 err = -ENOMEM;
3050                 goto err;
3051         }
3052         dev_net_set(dev, net);
3053         dev->rtnl_link_ops = &ppp_link_ops;
3054 
3055         rtnl_lock();
3056 
3057         err = ppp_dev_configure(net, dev, &conf);
3058         if (err < 0)
3059                 goto err_dev;
3060         ppp = netdev_priv(dev);
3061         *unit = ppp->file.index;
3062 
3063         rtnl_unlock();
3064 
3065         return 0;
3066 
3067 err_dev:
3068         rtnl_unlock();
3069         free_netdev(dev);
3070 err:
3071         return err;
3072 }
3073 
3074 /*
3075  * Initialize a ppp_file structure.
3076  */
3077 static void
3078 init_ppp_file(struct ppp_file *pf, int kind)
3079 {
3080         pf->kind = kind;
3081         skb_queue_head_init(&pf->xq);
3082         skb_queue_head_init(&pf->rq);
3083         refcount_set(&pf->refcnt, 1);
3084         init_waitqueue_head(&pf->rwait);
3085 }
3086 
3087 /*
3088  * Free the memory used by a ppp unit.  This is only called once
3089  * there are no channels connected to the unit and no file structs
3090  * that reference the unit.
3091  */
3092 static void ppp_destroy_interface(struct ppp *ppp)
3093 {
3094         atomic_dec(&ppp_unit_count);
3095 
3096         if (!ppp->file.dead || ppp->n_channels) {
3097                 /* "can't happen" */
3098                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3099                            "but dead=%d n_channels=%d !\n",
3100                            ppp, ppp->file.dead, ppp->n_channels);
3101                 return;
3102         }
3103 
3104         ppp_ccp_closed(ppp);
3105         if (ppp->vj) {
3106                 slhc_free(ppp->vj);
3107                 ppp->vj = NULL;
3108         }
3109         skb_queue_purge(&ppp->file.xq);
3110         skb_queue_purge(&ppp->file.rq);
3111 #ifdef CONFIG_PPP_MULTILINK
3112         skb_queue_purge(&ppp->mrq);
3113 #endif /* CONFIG_PPP_MULTILINK */
3114 #ifdef CONFIG_PPP_FILTER
3115         if (ppp->pass_filter) {
3116                 bpf_prog_destroy(ppp->pass_filter);
3117                 ppp->pass_filter = NULL;
3118         }
3119 
3120         if (ppp->active_filter) {
3121                 bpf_prog_destroy(ppp->active_filter);
3122                 ppp->active_filter = NULL;
3123         }
3124 #endif /* CONFIG_PPP_FILTER */
3125 
3126         kfree_skb(ppp->xmit_pending);
3127         free_percpu(ppp->xmit_recursion);
3128 
3129         free_netdev(ppp->dev);
3130 }
3131 
3132 /*
3133  * Locate an existing ppp unit.
3134  * The caller should have locked the all_ppp_mutex.
3135  */
3136 static struct ppp *
3137 ppp_find_unit(struct ppp_net *pn, int unit)
3138 {
3139         return unit_find(&pn->units_idr, unit);
3140 }
3141 
3142 /*
3143  * Locate an existing ppp channel.
3144  * The caller should have locked the all_channels_lock.
3145  * First we look in the new_channels list, then in the
3146  * all_channels list.  If found in the new_channels list,
3147  * we move it to the all_channels list.  This is for speed
3148  * when we have a lot of channels in use.
3149  */
3150 static struct channel *
3151 ppp_find_channel(struct ppp_net *pn, int unit)
3152 {
3153         struct channel *pch;
3154 
3155         list_for_each_entry(pch, &pn->new_channels, list) {
3156                 if (pch->file.index == unit) {
3157                         list_move(&pch->list, &pn->all_channels);
3158                         return pch;
3159                 }
3160         }
3161 
3162         list_for_each_entry(pch, &pn->all_channels, list) {
3163                 if (pch->file.index == unit)
3164                         return pch;
3165         }
3166 
3167         return NULL;
3168 }
3169 
3170 /*
3171  * Connect a PPP channel to a PPP interface unit.
3172  */
3173 static int
3174 ppp_connect_channel(struct channel *pch, int unit)
3175 {
3176         struct ppp *ppp;
3177         struct ppp_net *pn;
3178         int ret = -ENXIO;
3179         int hdrlen;
3180 
3181         pn = ppp_pernet(pch->chan_net);
3182 
3183         mutex_lock(&pn->all_ppp_mutex);
3184         ppp = ppp_find_unit(pn, unit);
3185         if (!ppp)
3186                 goto out;
3187         write_lock_bh(&pch->upl);
3188         ret = -EINVAL;
3189         if (pch->ppp)
3190                 goto outl;
3191 
3192         ppp_lock(ppp);
3193         spin_lock_bh(&pch->downl);
3194         if (!pch->chan) {
3195                 /* Don't connect unregistered channels */
3196                 spin_unlock_bh(&pch->downl);
3197                 ppp_unlock(ppp);
3198                 ret = -ENOTCONN;
3199                 goto outl;
3200         }
3201         spin_unlock_bh(&pch->downl);
3202         if (pch->file.hdrlen > ppp->file.hdrlen)
3203                 ppp->file.hdrlen = pch->file.hdrlen;
3204         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3205         if (hdrlen > ppp->dev->hard_header_len)
3206                 ppp->dev->hard_header_len = hdrlen;
3207         list_add_tail(&pch->clist, &ppp->channels);
3208         ++ppp->n_channels;
3209         pch->ppp = ppp;
3210         refcount_inc(&ppp->file.refcnt);
3211         ppp_unlock(ppp);
3212         ret = 0;
3213 
3214  outl:
3215         write_unlock_bh(&pch->upl);
3216  out:
3217         mutex_unlock(&pn->all_ppp_mutex);
3218         return ret;
3219 }
3220 
3221 /*
3222  * Disconnect a channel from its ppp unit.
3223  */
3224 static int
3225 ppp_disconnect_channel(struct channel *pch)
3226 {
3227         struct ppp *ppp;
3228         int err = -EINVAL;
3229 
3230         write_lock_bh(&pch->upl);
3231         ppp = pch->ppp;
3232         pch->ppp = NULL;
3233         write_unlock_bh(&pch->upl);
3234         if (ppp) {
3235                 /* remove it from the ppp unit's list */
3236                 ppp_lock(ppp);
3237                 list_del(&pch->clist);
3238                 if (--ppp->n_channels == 0)
3239                         wake_up_interruptible(&ppp->file.rwait);
3240                 ppp_unlock(ppp);
3241                 if (refcount_dec_and_test(&ppp->file.refcnt))
3242                         ppp_destroy_interface(ppp);
3243                 err = 0;
3244         }
3245         return err;
3246 }
3247 
3248 /*
3249  * Free up the resources used by a ppp channel.
3250  */
3251 static void ppp_destroy_channel(struct channel *pch)
3252 {
3253         put_net(pch->chan_net);
3254         pch->chan_net = NULL;
3255 
3256         atomic_dec(&channel_count);
3257 
3258         if (!pch->file.dead) {
3259                 /* "can't happen" */
3260                 pr_err("ppp: destroying undead channel %p !\n", pch);
3261                 return;
3262         }
3263         skb_queue_purge(&pch->file.xq);
3264         skb_queue_purge(&pch->file.rq);
3265         kfree(pch);
3266 }
3267 
3268 static void __exit ppp_cleanup(void)
3269 {
3270         /* should never happen */
3271         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3272                 pr_err("PPP: removing module but units remain!\n");
3273         rtnl_link_unregister(&ppp_link_ops);
3274         unregister_chrdev(PPP_MAJOR, "ppp");
3275         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3276         class_destroy(ppp_class);
3277         unregister_pernet_device(&ppp_net_ops);
3278 }
3279 
3280 /*
3281  * Units handling. Caller must protect concurrent access
3282  * by holding all_ppp_mutex
3283  */
3284 
3285 /* associate pointer with specified number */
3286 static int unit_set(struct idr *p, void *ptr, int n)
3287 {
3288         int unit;
3289 
3290         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3291         if (unit == -ENOSPC)
3292                 unit = -EINVAL;
3293         return unit;
3294 }
3295 
3296 /* get new free unit number and associate pointer with it */
3297 static int unit_get(struct idr *p, void *ptr)
3298 {
3299         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3300 }
3301 
3302 /* put unit number back to a pool */
3303 static void unit_put(struct idr *p, int n)
3304 {
3305         idr_remove(p, n);
3306 }
3307 
3308 /* get pointer associated with the number */
3309 static void *unit_find(struct idr *p, int n)
3310 {
3311         return idr_find(p, n);
3312 }
3313 
3314 /* Module/initialization stuff */
3315 
3316 module_init(ppp_init);
3317 module_exit(ppp_cleanup);
3318 
3319 EXPORT_SYMBOL(ppp_register_net_channel);
3320 EXPORT_SYMBOL(ppp_register_channel);
3321 EXPORT_SYMBOL(ppp_unregister_channel);
3322 EXPORT_SYMBOL(ppp_channel_index);
3323 EXPORT_SYMBOL(ppp_unit_number);
3324 EXPORT_SYMBOL(ppp_dev_name);
3325 EXPORT_SYMBOL(ppp_input);
3326 EXPORT_SYMBOL(ppp_input_error);
3327 EXPORT_SYMBOL(ppp_output_wakeup);
3328 EXPORT_SYMBOL(ppp_register_compressor);
3329 EXPORT_SYMBOL(ppp_unregister_compressor);
3330 MODULE_LICENSE("GPL");
3331 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3332 MODULE_ALIAS_RTNL_LINK("ppp");
3333 MODULE_ALIAS("devname:ppp");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/net/ppp/ppp_generic.c

DEFINITIONS
