git.rot13.org Git - linux/blob - drivers/net/ppp/ppp_generic.c

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