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