drivers/net/ppp/ppp_generic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic PPP layer for Linux.
   4  *
   5  * Copyright 1999-2002 Paul Mackerras.
   6  *
   7  * The generic PPP layer handles the PPP network interfaces, the
   8  * /dev/ppp device, packet and VJ compression, and multilink.
   9  * It talks to PPP `channels' via the interface defined in
  10  * include/linux/ppp_channel.h.  Channels provide the basic means for
  11  * sending and receiving PPP frames on some kind of communications
  12  * channel.
  13  *
  14  * Part of the code in this driver was inspired by the old async-only
  15  * PPP driver, written by Michael Callahan and Al Longyear, and
  16  * subsequently hacked by Paul Mackerras.
  17  *
  18  * ==FILEVERSION 20041108==
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched/signal.h>
  24 #include <linux/kmod.h>
  25 #include <linux/init.h>
  26 #include <linux/list.h>
  27 #include <linux/idr.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/poll.h>
  30 #include <linux/ppp_defs.h>
  31 #include <linux/filter.h>
  32 #include <linux/ppp-ioctl.h>
  33 #include <linux/ppp_channel.h>
  34 #include <linux/ppp-comp.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/rtnetlink.h>
  37 #include <linux/if_arp.h>
  38 #include <linux/ip.h>
  39 #include <linux/tcp.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/rwsem.h>
  42 #include <linux/stddef.h>
  43 #include <linux/device.h>
  44 #include <linux/mutex.h>
  45 #include <linux/slab.h>
  46 #include <linux/file.h>
  47 #include <asm/unaligned.h>
  48 #include <net/slhc_vj.h>
  49 #include <linux/atomic.h>
  50 #include <linux/refcount.h>
  51
  52 #include <linux/nsproxy.h>
  53 #include <net/net_namespace.h>
  54 #include <net/netns/generic.h>
  55
  56 #define PPP_VERSION     "2.4.2"
  57
  58 /*
  59  * Network protocols we support.
  60  */
  61 #define NP_IP   0               /* Internet Protocol V4 */
  62 #define NP_IPV6 1               /* Internet Protocol V6 */
  63 #define NP_IPX  2               /* IPX protocol */
  64 #define NP_AT   3               /* Appletalk protocol */
  65 #define NP_MPLS_UC 4            /* MPLS unicast */
  66 #define NP_MPLS_MC 5            /* MPLS multicast */
  67 #define NUM_NP  6               /* Number of NPs. */
  68
  69 #define MPHDRLEN        6       /* multilink protocol header length */
  70 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  71
  72 #define PPP_PROTO_LEN   2
  73
  74 /*
  75  * An instance of /dev/ppp can be associated with either a ppp
  76  * interface unit or a ppp channel.  In both cases, file->private_data
  77  * points to one of these.
  78  */
  79 struct ppp_file {
  80         enum {
  81                 INTERFACE=1, CHANNEL
  82         }               kind;
  83         struct sk_buff_head xq;         /* pppd transmit queue */
  84         struct sk_buff_head rq;         /* receive queue for pppd */
  85         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  86         refcount_t      refcnt;         /* # refs (incl /dev/ppp attached) */
  87         int             hdrlen;         /* space to leave for headers */
  88         int             index;          /* interface unit / channel number */
  89         int             dead;           /* unit/channel has been shut down */
  90 };
  91
  92 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  93
  94 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  95 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  96
  97 /*
  98  * Data structure to hold primary network stats for which
  99  * we want to use 64 bit storage.  Other network stats
 100  * are stored in dev->stats of the ppp strucute.
 101  */
 102 struct ppp_link_stats {
 103         u64 rx_packets;
 104         u64 tx_packets;
 105         u64 rx_bytes;
 106         u64 tx_bytes;
 107 };
 108
 109 /*
 110  * Data structure describing one ppp unit.
 111  * A ppp unit corresponds to a ppp network interface device
 112  * and represents a multilink bundle.
 113  * It can have 0 or more ppp channels connected to it.
 114  */
 115 struct ppp {
 116         struct ppp_file file;           /* stuff for read/write/poll 0 */
 117         struct file     *owner;         /* file that owns this unit 48 */
 118         struct list_head channels;      /* list of attached channels 4c */
 119         int             n_channels;     /* how many channels are attached 54 */
 120         spinlock_t      rlock;          /* lock for receive side 58 */
 121         spinlock_t      wlock;          /* lock for transmit side 5c */
 122         int __percpu    *xmit_recursion; /* xmit recursion detect */
 123         int             mru;            /* max receive unit 60 */
 124         unsigned int    flags;          /* control bits 64 */
 125         unsigned int    xstate;         /* transmit state bits 68 */
 126         unsigned int    rstate;         /* receive state bits 6c */
 127         int             debug;          /* debug flags 70 */
 128         struct slcompress *vj;          /* state for VJ header compression */
 129         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 130         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 131         struct compressor *xcomp;       /* transmit packet compressor 8c */
 132         void            *xc_state;      /* its internal state 90 */
 133         struct compressor *rcomp;       /* receive decompressor 94 */
 134         void            *rc_state;      /* its internal state 98 */
 135         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 136         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 137         struct net_device *dev;         /* network interface device a4 */
 138         int             closing;        /* is device closing down? a8 */
 139 #ifdef CONFIG_PPP_MULTILINK
 140         int             nxchan;         /* next channel to send something on */
 141         u32             nxseq;          /* next sequence number to send */
 142         int             mrru;           /* MP: max reconst. receive unit */
 143         u32             nextseq;        /* MP: seq no of next packet */
 144         u32             minseq;         /* MP: min of most recent seqnos */
 145         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 146 #endif /* CONFIG_PPP_MULTILINK */
 147 #ifdef CONFIG_PPP_FILTER
 148         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 149         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 150 #endif /* CONFIG_PPP_FILTER */
 151         struct net      *ppp_net;       /* the net we belong to */
 152         struct ppp_link_stats stats64;  /* 64 bit network stats */
 153 };
 154
 155 /*
 156  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 157  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 158  * SC_MUST_COMP
 159  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 160  * Bits in xstate: SC_COMP_RUN
 161  */
 162 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 163                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 164                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 165
 166 /*
 167  * Private data structure for each channel.
 168  * This includes the data structure used for multilink.
 169  */
 170 struct channel {
 171         struct ppp_file file;           /* stuff for read/write/poll */
 172         struct list_head list;          /* link in all/new_channels list */
 173         struct ppp_channel *chan;       /* public channel data structure */
 174         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 175         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 176         struct ppp      *ppp;           /* ppp unit we're connected to */
 177         struct net      *chan_net;      /* the net channel belongs to */
 178         struct list_head clist;         /* link in list of channels per unit */
 179         rwlock_t        upl;            /* protects `ppp' */
 180 #ifdef CONFIG_PPP_MULTILINK
 181         u8              avail;          /* flag used in multilink stuff */
 182         u8              had_frag;       /* >= 1 fragments have been sent */
 183         u32             lastseq;        /* MP: last sequence # received */
 184         int             speed;          /* speed of the corresponding ppp channel*/
 185 #endif /* CONFIG_PPP_MULTILINK */
 186 };
 187
 188 struct ppp_config {
 189         struct file *file;
 190         s32 unit;
 191         bool ifname_is_set;
 192 };
 193
 194 /*
 195  * SMP locking issues:
 196  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 197  * list and the ppp.n_channels field, you need to take both locks
 198  * before you modify them.
 199  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 200  * channel.downl.
 201  */
 202
 203 static DEFINE_MUTEX(ppp_mutex);
 204 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 205 static atomic_t channel_count = ATOMIC_INIT(0);
 206
 207 /* per-net private data for this module */
 208 static unsigned int ppp_net_id __read_mostly;
 209 struct ppp_net {
 210         /* units to ppp mapping */
 211         struct idr units_idr;
 212
 213         /*
 214          * all_ppp_mutex protects the units_idr mapping.
 215          * It also ensures that finding a ppp unit in the units_idr
 216          * map and updating its file.refcnt field is atomic.
 217          */
 218         struct mutex all_ppp_mutex;
 219
 220         /* channels */
 221         struct list_head all_channels;
 222         struct list_head new_channels;
 223         int last_channel_index;
 224
 225         /*
 226          * all_channels_lock protects all_channels and
 227          * last_channel_index, and the atomicity of find
 228          * a channel and updating its file.refcnt field.
 229          */
 230         spinlock_t all_channels_lock;
 231 };
 232
 233 /* Get the PPP protocol number from a skb */
 234 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 235
 236 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 237 #define PPP_MAX_RQLEN   32
 238
 239 /*
 240  * Maximum number of multilink fragments queued up.
 241  * This has to be large enough to cope with the maximum latency of
 242  * the slowest channel relative to the others.  Strictly it should
 243  * depend on the number of channels and their characteristics.
 244  */
 245 #define PPP_MP_MAX_QLEN 128
 246
 247 /* Multilink header bits. */
 248 #define B       0x80            /* this fragment begins a packet */
 249 #define E       0x40            /* this fragment ends a packet */
 250
 251 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 252 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 253 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 254
 255 /* Prototypes. */
 256 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 257                         struct file *file, unsigned int cmd, unsigned long arg);
 258 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 259 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 260 static void ppp_push(struct ppp *ppp);
 261 static void ppp_channel_push(struct channel *pch);
 262 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 263                               struct channel *pch);
 264 static void ppp_receive_error(struct ppp *ppp);
 265 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 266 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 267                                             struct sk_buff *skb);
 268 #ifdef CONFIG_PPP_MULTILINK
 269 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 270                                 struct channel *pch);
 271 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 272 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 273 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 274 #endif /* CONFIG_PPP_MULTILINK */
 275 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
 276 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 277 static void ppp_ccp_closed(struct ppp *ppp);
 278 static struct compressor *find_compressor(int type);
 279 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 280 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 281 static void init_ppp_file(struct ppp_file *pf, int kind);
 282 static void ppp_destroy_interface(struct ppp *ppp);
 283 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 284 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 285 static int ppp_connect_channel(struct channel *pch, int unit);
 286 static int ppp_disconnect_channel(struct channel *pch);
 287 static void ppp_destroy_channel(struct channel *pch);
 288 static int unit_get(struct idr *p, void *ptr, int min);
 289 static int unit_set(struct idr *p, void *ptr, int n);
 290 static void unit_put(struct idr *p, int n);
 291 static void *unit_find(struct idr *p, int n);
 292 static void ppp_setup(struct net_device *dev);
 293
 294 static const struct net_device_ops ppp_netdev_ops;
 295
 296 static struct class *ppp_class;
 297
 298 /* per net-namespace data */
 299 static inline struct ppp_net *ppp_pernet(struct net *net)
 300 {
 301         return net_generic(net, ppp_net_id);
 302 }
 303
 304 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 305 static inline int proto_to_npindex(int proto)
 306 {
 307         switch (proto) {
 308         case PPP_IP:
 309                 return NP_IP;
 310         case PPP_IPV6:
 311                 return NP_IPV6;
 312         case PPP_IPX:
 313                 return NP_IPX;
 314         case PPP_AT:
 315                 return NP_AT;
 316         case PPP_MPLS_UC:
 317                 return NP_MPLS_UC;
 318         case PPP_MPLS_MC:
 319                 return NP_MPLS_MC;
 320         }
 321         return -EINVAL;
 322 }
 323
 324 /* Translates an NP index into a PPP protocol number */
 325 static const int npindex_to_proto[NUM_NP] = {
 326         PPP_IP,
 327         PPP_IPV6,
 328         PPP_IPX,
 329         PPP_AT,
 330         PPP_MPLS_UC,
 331         PPP_MPLS_MC,
 332 };
 333
 334 /* Translates an ethertype into an NP index */
 335 static inline int ethertype_to_npindex(int ethertype)
 336 {
 337         switch (ethertype) {
 338         case ETH_P_IP:
 339                 return NP_IP;
 340         case ETH_P_IPV6:
 341                 return NP_IPV6;
 342         case ETH_P_IPX:
 343                 return NP_IPX;
 344         case ETH_P_PPPTALK:
 345         case ETH_P_ATALK:
 346                 return NP_AT;
 347         case ETH_P_MPLS_UC:
 348                 return NP_MPLS_UC;
 349         case ETH_P_MPLS_MC:
 350                 return NP_MPLS_MC;
 351         }
 352         return -1;
 353 }
 354
 355 /* Translates an NP index into an ethertype */
 356 static const int npindex_to_ethertype[NUM_NP] = {
 357         ETH_P_IP,
 358         ETH_P_IPV6,
 359         ETH_P_IPX,
 360         ETH_P_PPPTALK,
 361         ETH_P_MPLS_UC,
 362         ETH_P_MPLS_MC,
 363 };
 364
 365 /*
 366  * Locking shorthand.
 367  */
 368 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 369 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 370 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 371 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 372 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 373                                      ppp_recv_lock(ppp); } while (0)
 374 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 375                                      ppp_xmit_unlock(ppp); } while (0)
 376
 377 /*
 378  * /dev/ppp device routines.
 379  * The /dev/ppp device is used by pppd to control the ppp unit.
 380  * It supports the read, write, ioctl and poll functions.
 381  * Open instances of /dev/ppp can be in one of three states:
 382  * unattached, attached to a ppp unit, or attached to a ppp channel.
 383  */
 384 static int ppp_open(struct inode *inode, struct file *file)
 385 {
 386         /*
 387          * This could (should?) be enforced by the permissions on /dev/ppp.
 388          */
 389         if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
 390                 return -EPERM;
 391         return 0;
 392 }
 393
 394 static int ppp_release(struct inode *unused, struct file *file)
 395 {
 396         struct ppp_file *pf = file->private_data;
 397         struct ppp *ppp;
 398
 399         if (pf) {
 400                 file->private_data = NULL;
 401                 if (pf->kind == INTERFACE) {
 402                         ppp = PF_TO_PPP(pf);
 403                         rtnl_lock();
 404                         if (file == ppp->owner)
 405                                 unregister_netdevice(ppp->dev);
 406                         rtnl_unlock();
 407                 }
 408                 if (refcount_dec_and_test(&pf->refcnt)) {
 409                         switch (pf->kind) {
 410                         case INTERFACE:
 411                                 ppp_destroy_interface(PF_TO_PPP(pf));
 412                                 break;
 413                         case CHANNEL:
 414                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 415                                 break;
 416                         }
 417                 }
 418         }
 419         return 0;
 420 }
 421
 422 static ssize_t ppp_read(struct file *file, char __user *buf,
 423                         size_t count, loff_t *ppos)
 424 {
 425         struct ppp_file *pf = file->private_data;
 426         DECLARE_WAITQUEUE(wait, current);
 427         ssize_t ret;
 428         struct sk_buff *skb = NULL;
 429         struct iovec iov;
 430         struct iov_iter to;
 431
 432         ret = count;
 433
 434         if (!pf)
 435                 return -ENXIO;
 436         add_wait_queue(&pf->rwait, &wait);
 437         for (;;) {
 438                 set_current_state(TASK_INTERRUPTIBLE);
 439                 skb = skb_dequeue(&pf->rq);
 440                 if (skb)
 441                         break;
 442                 ret = 0;
 443                 if (pf->dead)
 444                         break;
 445                 if (pf->kind == INTERFACE) {
 446                         /*
 447                          * Return 0 (EOF) on an interface that has no
 448                          * channels connected, unless it is looping
 449                          * network traffic (demand mode).
 450                          */
 451                         struct ppp *ppp = PF_TO_PPP(pf);
 452
 453                         ppp_recv_lock(ppp);
 454                         if (ppp->n_channels == 0 &&
 455                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 456                                 ppp_recv_unlock(ppp);
 457                                 break;
 458                         }
 459                         ppp_recv_unlock(ppp);
 460                 }
 461                 ret = -EAGAIN;
 462                 if (file->f_flags & O_NONBLOCK)
 463                         break;
 464                 ret = -ERESTARTSYS;
 465                 if (signal_pending(current))
 466                         break;
 467                 schedule();
 468         }
 469         set_current_state(TASK_RUNNING);
 470         remove_wait_queue(&pf->rwait, &wait);
 471
 472         if (!skb)
 473                 goto out;
 474
 475         ret = -EOVERFLOW;
 476         if (skb->len > count)
 477                 goto outf;
 478         ret = -EFAULT;
 479         iov.iov_base = buf;
 480         iov.iov_len = count;
 481         iov_iter_init(&to, READ, &iov, 1, count);
 482         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 483                 goto outf;
 484         ret = skb->len;
 485
 486  outf:
 487         kfree_skb(skb);
 488  out:
 489         return ret;
 490 }
 491
 492 static ssize_t ppp_write(struct file *file, const char __user *buf,
 493                          size_t count, loff_t *ppos)
 494 {
 495         struct ppp_file *pf = file->private_data;
 496         struct sk_buff *skb;
 497         ssize_t ret;
 498
 499         if (!pf)
 500                 return -ENXIO;
 501         /* All PPP packets should start with the 2-byte protocol */
 502         if (count < PPP_PROTO_LEN)
 503                 return -EINVAL;
 504         ret = -ENOMEM;
 505         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 506         if (!skb)
 507                 goto out;
 508         skb_reserve(skb, pf->hdrlen);
 509         ret = -EFAULT;
 510         if (copy_from_user(skb_put(skb, count), buf, count)) {
 511                 kfree_skb(skb);
 512                 goto out;
 513         }
 514
 515         switch (pf->kind) {
 516         case INTERFACE:
 517                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 518                 break;
 519         case CHANNEL:
 520                 skb_queue_tail(&pf->xq, skb);
 521                 ppp_channel_push(PF_TO_CHANNEL(pf));
 522                 break;
 523         }
 524
 525         ret = count;
 526
 527  out:
 528         return ret;
 529 }
 530
 531 /* No kernel lock - fine */
 532 static __poll_t ppp_poll(struct file *file, poll_table *wait)
 533 {
 534         struct ppp_file *pf = file->private_data;
 535         __poll_t mask;
 536
 537         if (!pf)
 538                 return 0;
 539         poll_wait(file, &pf->rwait, wait);
 540         mask = EPOLLOUT | EPOLLWRNORM;
 541         if (skb_peek(&pf->rq))
 542                 mask |= EPOLLIN | EPOLLRDNORM;
 543         if (pf->dead)
 544                 mask |= EPOLLHUP;
 545         else if (pf->kind == INTERFACE) {
 546                 /* see comment in ppp_read */
 547                 struct ppp *ppp = PF_TO_PPP(pf);
 548
 549                 ppp_recv_lock(ppp);
 550                 if (ppp->n_channels == 0 &&
 551                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 552                         mask |= EPOLLIN | EPOLLRDNORM;
 553                 ppp_recv_unlock(ppp);
 554         }
 555
 556         return mask;
 557 }
 558
 559 #ifdef CONFIG_PPP_FILTER
 560 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
 561 {
 562         struct sock_fprog_kern fprog;
 563         struct bpf_prog *res = NULL;
 564         int err;
 565
 566         if (!uprog->len)
 567                 return NULL;
 568
 569         /* uprog->len is unsigned short, so no overflow here */
 570         fprog.len = uprog->len;
 571         fprog.filter = memdup_user(uprog->filter,
 572                                    uprog->len * sizeof(struct sock_filter));
 573         if (IS_ERR(fprog.filter))
 574                 return ERR_CAST(fprog.filter);
 575
 576         err = bpf_prog_create(&res, &fprog);
 577         kfree(fprog.filter);
 578
 579         return err ? ERR_PTR(err) : res;
 580 }
 581
 582 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
 583 {
 584         struct sock_fprog uprog;
 585
 586         if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
 587                 return ERR_PTR(-EFAULT);
 588         return get_filter(&uprog);
 589 }
 590
 591 #ifdef CONFIG_COMPAT
 592 struct sock_fprog32 {
 593         unsigned short len;
 594         compat_caddr_t filter;
 595 };
 596
 597 #define PPPIOCSPASS32           _IOW('t', 71, struct sock_fprog32)
 598 #define PPPIOCSACTIVE32         _IOW('t', 70, struct sock_fprog32)
 599
 600 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
 601 {
 602         struct sock_fprog32 uprog32;
 603         struct sock_fprog uprog;
 604
 605         if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
 606                 return ERR_PTR(-EFAULT);
 607         uprog.len = uprog32.len;
 608         uprog.filter = compat_ptr(uprog32.filter);
 609         return get_filter(&uprog);
 610 }
 611 #endif
 612 #endif
 613
 614 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 615 {
 616         struct ppp_file *pf;
 617         struct ppp *ppp;
 618         int err = -EFAULT, val, val2, i;
 619         struct ppp_idle32 idle32;
 620         struct ppp_idle64 idle64;
 621         struct npioctl npi;
 622         int unit, cflags;
 623         struct slcompress *vj;
 624         void __user *argp = (void __user *)arg;
 625         int __user *p = argp;
 626
 627         mutex_lock(&ppp_mutex);
 628
 629         pf = file->private_data;
 630         if (!pf) {
 631                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 632                                            pf, file, cmd, arg);
 633                 goto out;
 634         }
 635
 636         if (cmd == PPPIOCDETACH) {
 637                 /*
 638                  * PPPIOCDETACH is no longer supported as it was heavily broken,
 639                  * and is only known to have been used by pppd older than
 640                  * ppp-2.4.2 (released November 2003).
 641                  */
 642                 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
 643                              current->comm, current->pid);
 644                 err = -EINVAL;
 645                 goto out;
 646         }
 647
 648         if (pf->kind == CHANNEL) {
 649                 struct channel *pch;
 650                 struct ppp_channel *chan;
 651
 652                 pch = PF_TO_CHANNEL(pf);
 653
 654                 switch (cmd) {
 655                 case PPPIOCCONNECT:
 656                         if (get_user(unit, p))
 657                                 break;
 658                         err = ppp_connect_channel(pch, unit);
 659                         break;
 660
 661                 case PPPIOCDISCONN:
 662                         err = ppp_disconnect_channel(pch);
 663                         break;
 664
 665                 default:
 666                         down_read(&pch->chan_sem);
 667                         chan = pch->chan;
 668                         err = -ENOTTY;
 669                         if (chan && chan->ops->ioctl)
 670                                 err = chan->ops->ioctl(chan, cmd, arg);
 671                         up_read(&pch->chan_sem);
 672                 }
 673                 goto out;
 674         }
 675
 676         if (pf->kind != INTERFACE) {
 677                 /* can't happen */
 678                 pr_err("PPP: not interface or channel??\n");
 679                 err = -EINVAL;
 680                 goto out;
 681         }
 682
 683         ppp = PF_TO_PPP(pf);
 684         switch (cmd) {
 685         case PPPIOCSMRU:
 686                 if (get_user(val, p))
 687                         break;
 688                 ppp->mru = val;
 689                 err = 0;
 690                 break;
 691
 692         case PPPIOCSFLAGS:
 693                 if (get_user(val, p))
 694                         break;
 695                 ppp_lock(ppp);
 696                 cflags = ppp->flags & ~val;
 697 #ifdef CONFIG_PPP_MULTILINK
 698                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 699                         ppp->nextseq = 0;
 700 #endif
 701                 ppp->flags = val & SC_FLAG_BITS;
 702                 ppp_unlock(ppp);
 703                 if (cflags & SC_CCP_OPEN)
 704                         ppp_ccp_closed(ppp);
 705                 err = 0;
 706                 break;
 707
 708         case PPPIOCGFLAGS:
 709                 val = ppp->flags | ppp->xstate | ppp->rstate;
 710                 if (put_user(val, p))
 711                         break;
 712                 err = 0;
 713                 break;
 714
 715         case PPPIOCSCOMPRESS:
 716         {
 717                 struct ppp_option_data data;
 718                 if (copy_from_user(&data, argp, sizeof(data)))
 719                         err = -EFAULT;
 720                 else
 721                         err = ppp_set_compress(ppp, &data);
 722                 break;
 723         }
 724         case PPPIOCGUNIT:
 725                 if (put_user(ppp->file.index, p))
 726                         break;
 727                 err = 0;
 728                 break;
 729
 730         case PPPIOCSDEBUG:
 731                 if (get_user(val, p))
 732                         break;
 733                 ppp->debug = val;
 734                 err = 0;
 735                 break;
 736
 737         case PPPIOCGDEBUG:
 738                 if (put_user(ppp->debug, p))
 739                         break;
 740                 err = 0;
 741                 break;
 742
 743         case PPPIOCGIDLE32:
 744                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 745                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
 746                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
 747                         break;
 748                 err = 0;
 749                 break;
 750
 751         case PPPIOCGIDLE64:
 752                 idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 753                 idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
 754                 if (copy_to_user(argp, &idle64, sizeof(idle64)))
 755                         break;
 756                 err = 0;
 757                 break;
 758
 759         case PPPIOCSMAXCID:
 760                 if (get_user(val, p))
 761                         break;
 762                 val2 = 15;
 763                 if ((val >> 16) != 0) {
 764                         val2 = val >> 16;
 765                         val &= 0xffff;
 766                 }
 767                 vj = slhc_init(val2+1, val+1);
 768                 if (IS_ERR(vj)) {
 769                         err = PTR_ERR(vj);
 770                         break;
 771                 }
 772                 ppp_lock(ppp);
 773                 if (ppp->vj)
 774                         slhc_free(ppp->vj);
 775                 ppp->vj = vj;
 776                 ppp_unlock(ppp);
 777                 err = 0;
 778                 break;
 779
 780         case PPPIOCGNPMODE:
 781         case PPPIOCSNPMODE:
 782                 if (copy_from_user(&npi, argp, sizeof(npi)))
 783                         break;
 784                 err = proto_to_npindex(npi.protocol);
 785                 if (err < 0)
 786                         break;
 787                 i = err;
 788                 if (cmd == PPPIOCGNPMODE) {
 789                         err = -EFAULT;
 790                         npi.mode = ppp->npmode[i];
 791                         if (copy_to_user(argp, &npi, sizeof(npi)))
 792                                 break;
 793                 } else {
 794                         ppp->npmode[i] = npi.mode;
 795                         /* we may be able to transmit more packets now (??) */
 796                         netif_wake_queue(ppp->dev);
 797                 }
 798                 err = 0;
 799                 break;
 800
 801 #ifdef CONFIG_PPP_FILTER
 802         case PPPIOCSPASS:
 803         case PPPIOCSACTIVE:
 804         {
 805                 struct bpf_prog *filter = ppp_get_filter(argp);
 806                 struct bpf_prog **which;
 807
 808                 if (IS_ERR(filter)) {
 809                         err = PTR_ERR(filter);
 810                         break;
 811                 }
 812                 if (cmd == PPPIOCSPASS)
 813                         which = &ppp->pass_filter;
 814                 else
 815                         which = &ppp->active_filter;
 816                 ppp_lock(ppp);
 817                 if (*which)
 818                         bpf_prog_destroy(*which);
 819                 *which = filter;
 820                 ppp_unlock(ppp);
 821                 err = 0;
 822                 break;
 823         }
 824 #endif /* CONFIG_PPP_FILTER */
 825
 826 #ifdef CONFIG_PPP_MULTILINK
 827         case PPPIOCSMRRU:
 828                 if (get_user(val, p))
 829                         break;
 830                 ppp_recv_lock(ppp);
 831                 ppp->mrru = val;
 832                 ppp_recv_unlock(ppp);
 833                 err = 0;
 834                 break;
 835 #endif /* CONFIG_PPP_MULTILINK */
 836
 837         default:
 838                 err = -ENOTTY;
 839         }
 840
 841 out:
 842         mutex_unlock(&ppp_mutex);
 843
 844         return err;
 845 }
 846
 847 #ifdef CONFIG_COMPAT
 848 struct ppp_option_data32 {
 849         compat_uptr_t           ptr;
 850         u32                     length;
 851         compat_int_t            transmit;
 852 };
 853 #define PPPIOCSCOMPRESS32       _IOW('t', 77, struct ppp_option_data32)
 854
 855 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 856 {
 857         struct ppp_file *pf;
 858         int err = -ENOIOCTLCMD;
 859         void __user *argp = (void __user *)arg;
 860
 861         mutex_lock(&ppp_mutex);
 862
 863         pf = file->private_data;
 864         if (pf && pf->kind == INTERFACE) {
 865                 struct ppp *ppp = PF_TO_PPP(pf);
 866                 switch (cmd) {
 867 #ifdef CONFIG_PPP_FILTER
 868                 case PPPIOCSPASS32:
 869                 case PPPIOCSACTIVE32:
 870                 {
 871                         struct bpf_prog *filter = compat_ppp_get_filter(argp);
 872                         struct bpf_prog **which;
 873
 874                         if (IS_ERR(filter)) {
 875                                 err = PTR_ERR(filter);
 876                                 break;
 877                         }
 878                         if (cmd == PPPIOCSPASS32)
 879                                 which = &ppp->pass_filter;
 880                         else
 881                                 which = &ppp->active_filter;
 882                         ppp_lock(ppp);
 883                         if (*which)
 884                                 bpf_prog_destroy(*which);
 885                         *which = filter;
 886                         ppp_unlock(ppp);
 887                         err = 0;
 888                         break;
 889                 }
 890 #endif /* CONFIG_PPP_FILTER */
 891                 case PPPIOCSCOMPRESS32:
 892                 {
 893                         struct ppp_option_data32 data32;
 894                         if (copy_from_user(&data32, argp, sizeof(data32))) {
 895                                 err = -EFAULT;
 896                         } else {
 897                                 struct ppp_option_data data = {
 898                                         .ptr = compat_ptr(data32.ptr),
 899                                         .length = data32.length,
 900                                         .transmit = data32.transmit
 901                                 };
 902                                 err = ppp_set_compress(ppp, &data);
 903                         }
 904                         break;
 905                 }
 906                 }
 907         }
 908         mutex_unlock(&ppp_mutex);
 909
 910         /* all other commands have compatible arguments */
 911         if (err == -ENOIOCTLCMD)
 912                 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 913
 914         return err;
 915 }
 916 #endif
 917
 918 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 919                         struct file *file, unsigned int cmd, unsigned long arg)
 920 {
 921         int unit, err = -EFAULT;
 922         struct ppp *ppp;
 923         struct channel *chan;
 924         struct ppp_net *pn;
 925         int __user *p = (int __user *)arg;
 926
 927         switch (cmd) {
 928         case PPPIOCNEWUNIT:
 929                 /* Create a new ppp unit */
 930                 if (get_user(unit, p))
 931                         break;
 932                 err = ppp_create_interface(net, file, &unit);
 933                 if (err < 0)
 934                         break;
 935
 936                 err = -EFAULT;
 937                 if (put_user(unit, p))
 938                         break;
 939                 err = 0;
 940                 break;
 941
 942         case PPPIOCATTACH:
 943                 /* Attach to an existing ppp unit */
 944                 if (get_user(unit, p))
 945                         break;
 946                 err = -ENXIO;
 947                 pn = ppp_pernet(net);
 948                 mutex_lock(&pn->all_ppp_mutex);
 949                 ppp = ppp_find_unit(pn, unit);
 950                 if (ppp) {
 951                         refcount_inc(&ppp->file.refcnt);
 952                         file->private_data = &ppp->file;
 953                         err = 0;
 954                 }
 955                 mutex_unlock(&pn->all_ppp_mutex);
 956                 break;
 957
 958         case PPPIOCATTCHAN:
 959                 if (get_user(unit, p))
 960                         break;
 961                 err = -ENXIO;
 962                 pn = ppp_pernet(net);
 963                 spin_lock_bh(&pn->all_channels_lock);
 964                 chan = ppp_find_channel(pn, unit);
 965                 if (chan) {
 966                         refcount_inc(&chan->file.refcnt);
 967                         file->private_data = &chan->file;
 968                         err = 0;
 969                 }
 970                 spin_unlock_bh(&pn->all_channels_lock);
 971                 break;
 972
 973         default:
 974                 err = -ENOTTY;
 975         }
 976
 977         return err;
 978 }
 979
 980 static const struct file_operations ppp_device_fops = {
 981         .owner          = THIS_MODULE,
 982         .read           = ppp_read,
 983         .write          = ppp_write,
 984         .poll           = ppp_poll,
 985         .unlocked_ioctl = ppp_ioctl,
 986 #ifdef CONFIG_COMPAT
 987         .compat_ioctl   = ppp_compat_ioctl,
 988 #endif
 989         .open           = ppp_open,
 990         .release        = ppp_release,
 991         .llseek         = noop_llseek,
 992 };
 993
 994 static __net_init int ppp_init_net(struct net *net)
 995 {
 996         struct ppp_net *pn = net_generic(net, ppp_net_id);
 997
 998         idr_init(&pn->units_idr);
 999         mutex_init(&pn->all_ppp_mutex);
1000
1001         INIT_LIST_HEAD(&pn->all_channels);
1002         INIT_LIST_HEAD(&pn->new_channels);
1003
1004         spin_lock_init(&pn->all_channels_lock);
1005
1006         return 0;
1007 }
1008
1009 static __net_exit void ppp_exit_net(struct net *net)
1010 {
1011         struct ppp_net *pn = net_generic(net, ppp_net_id);
1012         struct net_device *dev;
1013         struct net_device *aux;
1014         struct ppp *ppp;
1015         LIST_HEAD(list);
1016         int id;
1017
1018         rtnl_lock();
1019         for_each_netdev_safe(net, dev, aux) {
1020                 if (dev->netdev_ops == &ppp_netdev_ops)
1021                         unregister_netdevice_queue(dev, &list);
1022         }
1023
1024         idr_for_each_entry(&pn->units_idr, ppp, id)
1025                 /* Skip devices already unregistered by previous loop */
1026                 if (!net_eq(dev_net(ppp->dev), net))
1027                         unregister_netdevice_queue(ppp->dev, &list);
1028
1029         unregister_netdevice_many(&list);
1030         rtnl_unlock();
1031
1032         mutex_destroy(&pn->all_ppp_mutex);
1033         idr_destroy(&pn->units_idr);
1034         WARN_ON_ONCE(!list_empty(&pn->all_channels));
1035         WARN_ON_ONCE(!list_empty(&pn->new_channels));
1036 }
1037
1038 static struct pernet_operations ppp_net_ops = {
1039         .init = ppp_init_net,
1040         .exit = ppp_exit_net,
1041         .id   = &ppp_net_id,
1042         .size = sizeof(struct ppp_net),
1043 };
1044
1045 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1046 {
1047         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1048         int ret;
1049
1050         mutex_lock(&pn->all_ppp_mutex);
1051
1052         if (unit < 0) {
1053                 ret = unit_get(&pn->units_idr, ppp, 0);
1054                 if (ret < 0)
1055                         goto err;
1056                 if (!ifname_is_set) {
1057                         while (1) {
1058                                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1059                                 if (!__dev_get_by_name(ppp->ppp_net, ppp->dev->name))
1060                                         break;
1061                                 unit_put(&pn->units_idr, ret);
1062                                 ret = unit_get(&pn->units_idr, ppp, ret + 1);
1063                                 if (ret < 0)
1064                                         goto err;
1065                         }
1066                 }
1067         } else {
1068                 /* Caller asked for a specific unit number. Fail with -EEXIST
1069                  * if unavailable. For backward compatibility, return -EEXIST
1070                  * too if idr allocation fails; this makes pppd retry without
1071                  * requesting a specific unit number.
1072                  */
1073                 if (unit_find(&pn->units_idr, unit)) {
1074                         ret = -EEXIST;
1075                         goto err;
1076                 }
1077                 ret = unit_set(&pn->units_idr, ppp, unit);
1078                 if (ret < 0) {
1079                         /* Rewrite error for backward compatibility */
1080                         ret = -EEXIST;
1081                         goto err;
1082                 }
1083         }
1084         ppp->file.index = ret;
1085
1086         if (!ifname_is_set)
1087                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1088
1089         mutex_unlock(&pn->all_ppp_mutex);
1090
1091         ret = register_netdevice(ppp->dev);
1092         if (ret < 0)
1093                 goto err_unit;
1094
1095         atomic_inc(&ppp_unit_count);
1096
1097         return 0;
1098
1099 err_unit:
1100         mutex_lock(&pn->all_ppp_mutex);
1101         unit_put(&pn->units_idr, ppp->file.index);
1102 err:
1103         mutex_unlock(&pn->all_ppp_mutex);
1104
1105         return ret;
1106 }
1107
1108 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1109                              const struct ppp_config *conf)
1110 {
1111         struct ppp *ppp = netdev_priv(dev);
1112         int indx;
1113         int err;
1114         int cpu;
1115
1116         ppp->dev = dev;
1117         ppp->ppp_net = src_net;
1118         ppp->mru = PPP_MRU;
1119         ppp->owner = conf->file;
1120
1121         init_ppp_file(&ppp->file, INTERFACE);
1122         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1123
1124         for (indx = 0; indx < NUM_NP; ++indx)
1125                 ppp->npmode[indx] = NPMODE_PASS;
1126         INIT_LIST_HEAD(&ppp->channels);
1127         spin_lock_init(&ppp->rlock);
1128         spin_lock_init(&ppp->wlock);
1129
1130         ppp->xmit_recursion = alloc_percpu(int);
1131         if (!ppp->xmit_recursion) {
1132                 err = -ENOMEM;
1133                 goto err1;
1134         }
1135         for_each_possible_cpu(cpu)
1136                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1137
1138 #ifdef CONFIG_PPP_MULTILINK
1139         ppp->minseq = -1;
1140         skb_queue_head_init(&ppp->mrq);
1141 #endif /* CONFIG_PPP_MULTILINK */
1142 #ifdef CONFIG_PPP_FILTER
1143         ppp->pass_filter = NULL;
1144         ppp->active_filter = NULL;
1145 #endif /* CONFIG_PPP_FILTER */
1146
1147         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1148         if (err < 0)
1149                 goto err2;
1150
1151         conf->file->private_data = &ppp->file;
1152
1153         return 0;
1154 err2:
1155         free_percpu(ppp->xmit_recursion);
1156 err1:
1157         return err;
1158 }
1159
1160 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1161         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1162 };
1163
1164 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1165                            struct netlink_ext_ack *extack)
1166 {
1167         if (!data)
1168                 return -EINVAL;
1169
1170         if (!data[IFLA_PPP_DEV_FD])
1171                 return -EINVAL;
1172         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1173                 return -EBADF;
1174
1175         return 0;
1176 }
1177
1178 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1179                           struct nlattr *tb[], struct nlattr *data[],
1180                           struct netlink_ext_ack *extack)
1181 {
1182         struct ppp_config conf = {
1183                 .unit = -1,
1184                 .ifname_is_set = true,
1185         };
1186         struct file *file;
1187         int err;
1188
1189         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1190         if (!file)
1191                 return -EBADF;
1192
1193         /* rtnl_lock is already held here, but ppp_create_interface() locks
1194          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1195          * possible deadlock due to lock order inversion, at the cost of
1196          * pushing the problem back to userspace.
1197          */
1198         if (!mutex_trylock(&ppp_mutex)) {
1199                 err = -EBUSY;
1200                 goto out;
1201         }
1202
1203         if (file->f_op != &ppp_device_fops || file->private_data) {
1204                 err = -EBADF;
1205                 goto out_unlock;
1206         }
1207
1208         conf.file = file;
1209
1210         /* Don't use device name generated by the rtnetlink layer when ifname
1211          * isn't specified. Let ppp_dev_configure() set the device name using
1212          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1213          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1214          */
1215         if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1216                 conf.ifname_is_set = false;
1217
1218         err = ppp_dev_configure(src_net, dev, &conf);
1219
1220 out_unlock:
1221         mutex_unlock(&ppp_mutex);
1222 out:
1223         fput(file);
1224
1225         return err;
1226 }
1227
1228 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1229 {
1230         unregister_netdevice_queue(dev, head);
1231 }
1232
1233 static size_t ppp_nl_get_size(const struct net_device *dev)
1234 {
1235         return 0;
1236 }
1237
1238 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1239 {
1240         return 0;
1241 }
1242
1243 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1244 {
1245         struct ppp *ppp = netdev_priv(dev);
1246
1247         return ppp->ppp_net;
1248 }
1249
1250 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1251         .kind           = "ppp",
1252         .maxtype        = IFLA_PPP_MAX,
1253         .policy         = ppp_nl_policy,
1254         .priv_size      = sizeof(struct ppp),
1255         .setup          = ppp_setup,
1256         .validate       = ppp_nl_validate,
1257         .newlink        = ppp_nl_newlink,
1258         .dellink        = ppp_nl_dellink,
1259         .get_size       = ppp_nl_get_size,
1260         .fill_info      = ppp_nl_fill_info,
1261         .get_link_net   = ppp_nl_get_link_net,
1262 };
1263
1264 #define PPP_MAJOR       108
1265
1266 /* Called at boot time if ppp is compiled into the kernel,
1267    or at module load time (from init_module) if compiled as a module. */
1268 static int __init ppp_init(void)
1269 {
1270         int err;
1271
1272         pr_info("PPP generic driver version " PPP_VERSION "\n");
1273
1274         err = register_pernet_device(&ppp_net_ops);
1275         if (err) {
1276                 pr_err("failed to register PPP pernet device (%d)\n", err);
1277                 goto out;
1278         }
1279
1280         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1281         if (err) {
1282                 pr_err("failed to register PPP device (%d)\n", err);
1283                 goto out_net;
1284         }
1285
1286         ppp_class = class_create(THIS_MODULE, "ppp");
1287         if (IS_ERR(ppp_class)) {
1288                 err = PTR_ERR(ppp_class);
1289                 goto out_chrdev;
1290         }
1291
1292         err = rtnl_link_register(&ppp_link_ops);
1293         if (err) {
1294                 pr_err("failed to register rtnetlink PPP handler\n");
1295                 goto out_class;
1296         }
1297
1298         /* not a big deal if we fail here :-) */
1299         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1300
1301         return 0;
1302
1303 out_class:
1304         class_destroy(ppp_class);
1305 out_chrdev:
1306         unregister_chrdev(PPP_MAJOR, "ppp");
1307 out_net:
1308         unregister_pernet_device(&ppp_net_ops);
1309 out:
1310         return err;
1311 }
1312
1313 /*
1314  * Network interface unit routines.
1315  */
1316 static netdev_tx_t
1317 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1318 {
1319         struct ppp *ppp = netdev_priv(dev);
1320         int npi, proto;
1321         unsigned char *pp;
1322
1323         npi = ethertype_to_npindex(ntohs(skb->protocol));
1324         if (npi < 0)
1325                 goto outf;
1326
1327         /* Drop, accept or reject the packet */
1328         switch (ppp->npmode[npi]) {
1329         case NPMODE_PASS:
1330                 break;
1331         case NPMODE_QUEUE:
1332                 /* it would be nice to have a way to tell the network
1333                    system to queue this one up for later. */
1334                 goto outf;
1335         case NPMODE_DROP:
1336         case NPMODE_ERROR:
1337                 goto outf;
1338         }
1339
1340         /* Put the 2-byte PPP protocol number on the front,
1341            making sure there is room for the address and control fields. */
1342         if (skb_cow_head(skb, PPP_HDRLEN))
1343                 goto outf;
1344
1345         pp = skb_push(skb, 2);
1346         proto = npindex_to_proto[npi];
1347         put_unaligned_be16(proto, pp);
1348
1349         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1350         ppp_xmit_process(ppp, skb);
1351
1352         return NETDEV_TX_OK;
1353
1354  outf:
1355         kfree_skb(skb);
1356         ++dev->stats.tx_dropped;
1357         return NETDEV_TX_OK;
1358 }
1359
1360 static int
1361 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1362 {
1363         struct ppp *ppp = netdev_priv(dev);
1364         int err = -EFAULT;
1365         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1366         struct ppp_stats stats;
1367         struct ppp_comp_stats cstats;
1368         char *vers;
1369
1370         switch (cmd) {
1371         case SIOCGPPPSTATS:
1372                 ppp_get_stats(ppp, &stats);
1373                 if (copy_to_user(addr, &stats, sizeof(stats)))
1374                         break;
1375                 err = 0;
1376                 break;
1377
1378         case SIOCGPPPCSTATS:
1379                 memset(&cstats, 0, sizeof(cstats));
1380                 if (ppp->xc_state)
1381                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1382                 if (ppp->rc_state)
1383                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1384                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1385                         break;
1386                 err = 0;
1387                 break;
1388
1389         case SIOCGPPPVER:
1390                 vers = PPP_VERSION;
1391                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1392                         break;
1393                 err = 0;
1394                 break;
1395
1396         default:
1397                 err = -EINVAL;
1398         }
1399
1400         return err;
1401 }
1402
1403 static void
1404 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1405 {
1406         struct ppp *ppp = netdev_priv(dev);
1407
1408         ppp_recv_lock(ppp);
1409         stats64->rx_packets = ppp->stats64.rx_packets;
1410         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1411         ppp_recv_unlock(ppp);
1412
1413         ppp_xmit_lock(ppp);
1414         stats64->tx_packets = ppp->stats64.tx_packets;
1415         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1416         ppp_xmit_unlock(ppp);
1417
1418         stats64->rx_errors        = dev->stats.rx_errors;
1419         stats64->tx_errors        = dev->stats.tx_errors;
1420         stats64->rx_dropped       = dev->stats.rx_dropped;
1421         stats64->tx_dropped       = dev->stats.tx_dropped;
1422         stats64->rx_length_errors = dev->stats.rx_length_errors;
1423 }
1424
1425 static int ppp_dev_init(struct net_device *dev)
1426 {
1427         struct ppp *ppp;
1428
1429         netdev_lockdep_set_classes(dev);
1430
1431         ppp = netdev_priv(dev);
1432         /* Let the netdevice take a reference on the ppp file. This ensures
1433          * that ppp_destroy_interface() won't run before the device gets
1434          * unregistered.
1435          */
1436         refcount_inc(&ppp->file.refcnt);
1437
1438         return 0;
1439 }
1440
1441 static void ppp_dev_uninit(struct net_device *dev)
1442 {
1443         struct ppp *ppp = netdev_priv(dev);
1444         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1445
1446         ppp_lock(ppp);
1447         ppp->closing = 1;
1448         ppp_unlock(ppp);
1449
1450         mutex_lock(&pn->all_ppp_mutex);
1451         unit_put(&pn->units_idr, ppp->file.index);
1452         mutex_unlock(&pn->all_ppp_mutex);
1453
1454         ppp->owner = NULL;
1455
1456         ppp->file.dead = 1;
1457         wake_up_interruptible(&ppp->file.rwait);
1458 }
1459
1460 static void ppp_dev_priv_destructor(struct net_device *dev)
1461 {
1462         struct ppp *ppp;
1463
1464         ppp = netdev_priv(dev);
1465         if (refcount_dec_and_test(&ppp->file.refcnt))
1466                 ppp_destroy_interface(ppp);
1467 }
1468
1469 static const struct net_device_ops ppp_netdev_ops = {
1470         .ndo_init        = ppp_dev_init,
1471         .ndo_uninit      = ppp_dev_uninit,
1472         .ndo_start_xmit  = ppp_start_xmit,
1473         .ndo_do_ioctl    = ppp_net_ioctl,
1474         .ndo_get_stats64 = ppp_get_stats64,
1475 };
1476
1477 static struct device_type ppp_type = {
1478         .name = "ppp",
1479 };
1480
1481 static void ppp_setup(struct net_device *dev)
1482 {
1483         dev->netdev_ops = &ppp_netdev_ops;
1484         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1485
1486         dev->features |= NETIF_F_LLTX;
1487
1488         dev->hard_header_len = PPP_HDRLEN;
1489         dev->mtu = PPP_MRU;
1490         dev->addr_len = 0;
1491         dev->tx_queue_len = 3;
1492         dev->type = ARPHRD_PPP;
1493         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1494         dev->priv_destructor = ppp_dev_priv_destructor;
1495         netif_keep_dst(dev);
1496 }
1497
1498 /*
1499  * Transmit-side routines.
1500  */
1501
1502 /* Called to do any work queued up on the transmit side that can now be done */
1503 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1504 {
1505         ppp_xmit_lock(ppp);
1506         if (!ppp->closing) {
1507                 ppp_push(ppp);
1508
1509                 if (skb)
1510                         skb_queue_tail(&ppp->file.xq, skb);
1511                 while (!ppp->xmit_pending &&
1512                        (skb = skb_dequeue(&ppp->file.xq)))
1513                         ppp_send_frame(ppp, skb);
1514                 /* If there's no work left to do, tell the core net
1515                    code that we can accept some more. */
1516                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1517                         netif_wake_queue(ppp->dev);
1518                 else
1519                         netif_stop_queue(ppp->dev);
1520         } else {
1521                 kfree_skb(skb);
1522         }
1523         ppp_xmit_unlock(ppp);
1524 }
1525
1526 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1527 {
1528         local_bh_disable();
1529
1530         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1531                 goto err;
1532
1533         (*this_cpu_ptr(ppp->xmit_recursion))++;
1534         __ppp_xmit_process(ppp, skb);
1535         (*this_cpu_ptr(ppp->xmit_recursion))--;
1536
1537         local_bh_enable();
1538
1539         return;
1540
1541 err:
1542         local_bh_enable();
1543
1544         kfree_skb(skb);
1545
1546         if (net_ratelimit())
1547                 netdev_err(ppp->dev, "recursion detected\n");
1548 }
1549
1550 static inline struct sk_buff *
1551 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1552 {
1553         struct sk_buff *new_skb;
1554         int len;
1555         int new_skb_size = ppp->dev->mtu +
1556                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1557         int compressor_skb_size = ppp->dev->mtu +
1558                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1559         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1560         if (!new_skb) {
1561                 if (net_ratelimit())
1562                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1563                 return NULL;
1564         }
1565         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1566                 skb_reserve(new_skb,
1567                             ppp->dev->hard_header_len - PPP_HDRLEN);
1568
1569         /* compressor still expects A/C bytes in hdr */
1570         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1571                                    new_skb->data, skb->len + 2,
1572                                    compressor_skb_size);
1573         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1574                 consume_skb(skb);
1575                 skb = new_skb;
1576                 skb_put(skb, len);
1577                 skb_pull(skb, 2);       /* pull off A/C bytes */
1578         } else if (len == 0) {
1579                 /* didn't compress, or CCP not up yet */
1580                 consume_skb(new_skb);
1581                 new_skb = skb;
1582         } else {
1583                 /*
1584                  * (len < 0)
1585                  * MPPE requires that we do not send unencrypted
1586                  * frames.  The compressor will return -1 if we
1587                  * should drop the frame.  We cannot simply test
1588                  * the compress_proto because MPPE and MPPC share
1589                  * the same number.
1590                  */
1591                 if (net_ratelimit())
1592                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1593                 kfree_skb(skb);
1594                 consume_skb(new_skb);
1595                 new_skb = NULL;
1596         }
1597         return new_skb;
1598 }
1599
1600 /*
1601  * Compress and send a frame.
1602  * The caller should have locked the xmit path,
1603  * and xmit_pending should be 0.
1604  */
1605 static void
1606 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1607 {
1608         int proto = PPP_PROTO(skb);
1609         struct sk_buff *new_skb;
1610         int len;
1611         unsigned char *cp;
1612
1613         if (proto < 0x8000) {
1614 #ifdef CONFIG_PPP_FILTER
1615                 /* check if we should pass this packet */
1616                 /* the filter instructions are constructed assuming
1617                    a four-byte PPP header on each packet */
1618                 *(u8 *)skb_push(skb, 2) = 1;
1619                 if (ppp->pass_filter &&
1620                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1621                         if (ppp->debug & 1)
1622                                 netdev_printk(KERN_DEBUG, ppp->dev,
1623                                               "PPP: outbound frame "
1624                                               "not passed\n");
1625                         kfree_skb(skb);
1626                         return;
1627                 }
1628                 /* if this packet passes the active filter, record the time */
1629                 if (!(ppp->active_filter &&
1630                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1631                         ppp->last_xmit = jiffies;
1632                 skb_pull(skb, 2);
1633 #else
1634                 /* for data packets, record the time */
1635                 ppp->last_xmit = jiffies;
1636 #endif /* CONFIG_PPP_FILTER */
1637         }
1638
1639         ++ppp->stats64.tx_packets;
1640         ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1641
1642         switch (proto) {
1643         case PPP_IP:
1644                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1645                         break;
1646                 /* try to do VJ TCP header compression */
1647                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1648                                     GFP_ATOMIC);
1649                 if (!new_skb) {
1650                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1651                         goto drop;
1652                 }
1653                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1654                 cp = skb->data + 2;
1655                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1656                                     new_skb->data + 2, &cp,
1657                                     !(ppp->flags & SC_NO_TCP_CCID));
1658                 if (cp == skb->data + 2) {
1659                         /* didn't compress */
1660                         consume_skb(new_skb);
1661                 } else {
1662                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1663                                 proto = PPP_VJC_COMP;
1664                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1665                         } else {
1666                                 proto = PPP_VJC_UNCOMP;
1667                                 cp[0] = skb->data[2];
1668                         }
1669                         consume_skb(skb);
1670                         skb = new_skb;
1671                         cp = skb_put(skb, len + 2);
1672                         cp[0] = 0;
1673                         cp[1] = proto;
1674                 }
1675                 break;
1676
1677         case PPP_CCP:
1678                 /* peek at outbound CCP frames */
1679                 ppp_ccp_peek(ppp, skb, 0);
1680                 break;
1681         }
1682
1683         /* try to do packet compression */
1684         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1685             proto != PPP_LCP && proto != PPP_CCP) {
1686                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1687                         if (net_ratelimit())
1688                                 netdev_err(ppp->dev,
1689                                            "ppp: compression required but "
1690                                            "down - pkt dropped.\n");
1691                         goto drop;
1692                 }
1693                 skb = pad_compress_skb(ppp, skb);
1694                 if (!skb)
1695                         goto drop;
1696         }
1697
1698         /*
1699          * If we are waiting for traffic (demand dialling),
1700          * queue it up for pppd to receive.
1701          */
1702         if (ppp->flags & SC_LOOP_TRAFFIC) {
1703                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1704                         goto drop;
1705                 skb_queue_tail(&ppp->file.rq, skb);
1706                 wake_up_interruptible(&ppp->file.rwait);
1707                 return;
1708         }
1709
1710         ppp->xmit_pending = skb;
1711         ppp_push(ppp);
1712         return;
1713
1714  drop:
1715         kfree_skb(skb);
1716         ++ppp->dev->stats.tx_errors;
1717 }
1718
1719 /*
1720  * Try to send the frame in xmit_pending.
1721  * The caller should have the xmit path locked.
1722  */
1723 static void
1724 ppp_push(struct ppp *ppp)
1725 {
1726         struct list_head *list;
1727         struct channel *pch;
1728         struct sk_buff *skb = ppp->xmit_pending;
1729
1730         if (!skb)
1731                 return;
1732
1733         list = &ppp->channels;
1734         if (list_empty(list)) {
1735                 /* nowhere to send the packet, just drop it */
1736                 ppp->xmit_pending = NULL;
1737                 kfree_skb(skb);
1738                 return;
1739         }
1740
1741         if ((ppp->flags & SC_MULTILINK) == 0) {
1742                 /* not doing multilink: send it down the first channel */
1743                 list = list->next;
1744                 pch = list_entry(list, struct channel, clist);
1745
1746                 spin_lock(&pch->downl);
1747                 if (pch->chan) {
1748                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1749                                 ppp->xmit_pending = NULL;
1750                 } else {
1751                         /* channel got unregistered */
1752                         kfree_skb(skb);
1753                         ppp->xmit_pending = NULL;
1754                 }
1755                 spin_unlock(&pch->downl);
1756                 return;
1757         }
1758
1759 #ifdef CONFIG_PPP_MULTILINK
1760         /* Multilink: fragment the packet over as many links
1761            as can take the packet at the moment. */
1762         if (!ppp_mp_explode(ppp, skb))
1763                 return;
1764 #endif /* CONFIG_PPP_MULTILINK */
1765
1766         ppp->xmit_pending = NULL;
1767         kfree_skb(skb);
1768 }
1769
1770 #ifdef CONFIG_PPP_MULTILINK
1771 static bool mp_protocol_compress __read_mostly = true;
1772 module_param(mp_protocol_compress, bool, 0644);
1773 MODULE_PARM_DESC(mp_protocol_compress,
1774                  "compress protocol id in multilink fragments");
1775
1776 /*
1777  * Divide a packet to be transmitted into fragments and
1778  * send them out the individual links.
1779  */
1780 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1781 {
1782         int len, totlen;
1783         int i, bits, hdrlen, mtu;
1784         int flen;
1785         int navail, nfree, nzero;
1786         int nbigger;
1787         int totspeed;
1788         int totfree;
1789         unsigned char *p, *q;
1790         struct list_head *list;
1791         struct channel *pch;
1792         struct sk_buff *frag;
1793         struct ppp_channel *chan;
1794
1795         totspeed = 0; /*total bitrate of the bundle*/
1796         nfree = 0; /* # channels which have no packet already queued */
1797         navail = 0; /* total # of usable channels (not deregistered) */
1798         nzero = 0; /* number of channels with zero speed associated*/
1799         totfree = 0; /*total # of channels available and
1800                                   *having no queued packets before
1801                                   *starting the fragmentation*/
1802
1803         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1804         i = 0;
1805         list_for_each_entry(pch, &ppp->channels, clist) {
1806                 if (pch->chan) {
1807                         pch->avail = 1;
1808                         navail++;
1809                         pch->speed = pch->chan->speed;
1810                 } else {
1811                         pch->avail = 0;
1812                 }
1813                 if (pch->avail) {
1814                         if (skb_queue_empty(&pch->file.xq) ||
1815                                 !pch->had_frag) {
1816                                         if (pch->speed == 0)
1817                                                 nzero++;
1818                                         else
1819                                                 totspeed += pch->speed;
1820
1821                                         pch->avail = 2;
1822                                         ++nfree;
1823                                         ++totfree;
1824                                 }
1825                         if (!pch->had_frag && i < ppp->nxchan)
1826                                 ppp->nxchan = i;
1827                 }
1828                 ++i;
1829         }
1830         /*
1831          * Don't start sending this packet unless at least half of
1832          * the channels are free.  This gives much better TCP
1833          * performance if we have a lot of channels.
1834          */
1835         if (nfree == 0 || nfree < navail / 2)
1836                 return 0; /* can't take now, leave it in xmit_pending */
1837
1838         /* Do protocol field compression */
1839         p = skb->data;
1840         len = skb->len;
1841         if (*p == 0 && mp_protocol_compress) {
1842                 ++p;
1843                 --len;
1844         }
1845
1846         totlen = len;
1847         nbigger = len % nfree;
1848
1849         /* skip to the channel after the one we last used
1850            and start at that one */
1851         list = &ppp->channels;
1852         for (i = 0; i < ppp->nxchan; ++i) {
1853                 list = list->next;
1854                 if (list == &ppp->channels) {
1855                         i = 0;
1856                         break;
1857                 }
1858         }
1859
1860         /* create a fragment for each channel */
1861         bits = B;
1862         while (len > 0) {
1863                 list = list->next;
1864                 if (list == &ppp->channels) {
1865                         i = 0;
1866                         continue;
1867                 }
1868                 pch = list_entry(list, struct channel, clist);
1869                 ++i;
1870                 if (!pch->avail)
1871                         continue;
1872
1873                 /*
1874                  * Skip this channel if it has a fragment pending already and
1875                  * we haven't given a fragment to all of the free channels.
1876                  */
1877                 if (pch->avail == 1) {
1878                         if (nfree > 0)
1879                                 continue;
1880                 } else {
1881                         pch->avail = 1;
1882                 }
1883
1884                 /* check the channel's mtu and whether it is still attached. */
1885                 spin_lock(&pch->downl);
1886                 if (pch->chan == NULL) {
1887                         /* can't use this channel, it's being deregistered */
1888                         if (pch->speed == 0)
1889                                 nzero--;
1890                         else
1891                                 totspeed -= pch->speed;
1892
1893                         spin_unlock(&pch->downl);
1894                         pch->avail = 0;
1895                         totlen = len;
1896                         totfree--;
1897                         nfree--;
1898                         if (--navail == 0)
1899                                 break;
1900                         continue;
1901                 }
1902
1903                 /*
1904                 *if the channel speed is not set divide
1905                 *the packet evenly among the free channels;
1906                 *otherwise divide it according to the speed
1907                 *of the channel we are going to transmit on
1908                 */
1909                 flen = len;
1910                 if (nfree > 0) {
1911                         if (pch->speed == 0) {
1912                                 flen = len/nfree;
1913                                 if (nbigger > 0) {
1914                                         flen++;
1915                                         nbigger--;
1916                                 }
1917                         } else {
1918                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1919                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1920                                 if (nbigger > 0) {
1921                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1922                                         nbigger -= ((totfree - nzero)*pch->speed)/
1923                                                         totspeed;
1924                                 }
1925                         }
1926                         nfree--;
1927                 }
1928
1929                 /*
1930                  *check if we are on the last channel or
1931                  *we exceded the length of the data to
1932                  *fragment
1933                  */
1934                 if ((nfree <= 0) || (flen > len))
1935                         flen = len;
1936                 /*
1937                  *it is not worth to tx on slow channels:
1938                  *in that case from the resulting flen according to the
1939                  *above formula will be equal or less than zero.
1940                  *Skip the channel in this case
1941                  */
1942                 if (flen <= 0) {
1943                         pch->avail = 2;
1944                         spin_unlock(&pch->downl);
1945                         continue;
1946                 }
1947
1948                 /*
1949                  * hdrlen includes the 2-byte PPP protocol field, but the
1950                  * MTU counts only the payload excluding the protocol field.
1951                  * (RFC1661 Section 2)
1952                  */
1953                 mtu = pch->chan->mtu - (hdrlen - 2);
1954                 if (mtu < 4)
1955                         mtu = 4;
1956                 if (flen > mtu)
1957                         flen = mtu;
1958                 if (flen == len)
1959                         bits |= E;
1960                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1961                 if (!frag)
1962                         goto noskb;
1963                 q = skb_put(frag, flen + hdrlen);
1964
1965                 /* make the MP header */
1966                 put_unaligned_be16(PPP_MP, q);
1967                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1968                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1969                         q[3] = ppp->nxseq;
1970                 } else {
1971                         q[2] = bits;
1972                         q[3] = ppp->nxseq >> 16;
1973                         q[4] = ppp->nxseq >> 8;
1974                         q[5] = ppp->nxseq;
1975                 }
1976
1977                 memcpy(q + hdrlen, p, flen);
1978
1979                 /* try to send it down the channel */
1980                 chan = pch->chan;
1981                 if (!skb_queue_empty(&pch->file.xq) ||
1982                         !chan->ops->start_xmit(chan, frag))
1983                         skb_queue_tail(&pch->file.xq, frag);
1984                 pch->had_frag = 1;
1985                 p += flen;
1986                 len -= flen;
1987                 ++ppp->nxseq;
1988                 bits = 0;
1989                 spin_unlock(&pch->downl);
1990         }
1991         ppp->nxchan = i;
1992
1993         return 1;
1994
1995  noskb:
1996         spin_unlock(&pch->downl);
1997         if (ppp->debug & 1)
1998                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1999         ++ppp->dev->stats.tx_errors;
2000         ++ppp->nxseq;
2001         return 1;       /* abandon the frame */
2002 }
2003 #endif /* CONFIG_PPP_MULTILINK */
2004
2005 /* Try to send data out on a channel */
2006 static void __ppp_channel_push(struct channel *pch)
2007 {
2008         struct sk_buff *skb;
2009         struct ppp *ppp;
2010
2011         spin_lock(&pch->downl);
2012         if (pch->chan) {
2013                 while (!skb_queue_empty(&pch->file.xq)) {
2014                         skb = skb_dequeue(&pch->file.xq);
2015                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2016                                 /* put the packet back and try again later */
2017                                 skb_queue_head(&pch->file.xq, skb);
2018                                 break;
2019                         }
2020                 }
2021         } else {
2022                 /* channel got deregistered */
2023                 skb_queue_purge(&pch->file.xq);
2024         }
2025         spin_unlock(&pch->downl);
2026         /* see if there is anything from the attached unit to be sent */
2027         if (skb_queue_empty(&pch->file.xq)) {
2028                 ppp = pch->ppp;
2029                 if (ppp)
2030                         __ppp_xmit_process(ppp, NULL);
2031         }
2032 }
2033
2034 static void ppp_channel_push(struct channel *pch)
2035 {
2036         read_lock_bh(&pch->upl);
2037         if (pch->ppp) {
2038                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2039                 __ppp_channel_push(pch);
2040                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2041         } else {
2042                 __ppp_channel_push(pch);
2043         }
2044         read_unlock_bh(&pch->upl);
2045 }
2046
2047 /*
2048  * Receive-side routines.
2049  */
2050
2051 struct ppp_mp_skb_parm {
2052         u32             sequence;
2053         u8              BEbits;
2054 };
2055 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
2056
2057 static inline void
2058 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2059 {
2060         ppp_recv_lock(ppp);
2061         if (!ppp->closing)
2062                 ppp_receive_frame(ppp, skb, pch);
2063         else
2064                 kfree_skb(skb);
2065         ppp_recv_unlock(ppp);
2066 }
2067
2068 /**
2069  * __ppp_decompress_proto - Decompress protocol field, slim version.
2070  * @skb: Socket buffer where protocol field should be decompressed. It must have
2071  *       at least 1 byte of head room and 1 byte of linear data. First byte of
2072  *       data must be a protocol field byte.
2073  *
2074  * Decompress protocol field in PPP header if it's compressed, e.g. when
2075  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2076  * length are done in this function.
2077  */
2078 static void __ppp_decompress_proto(struct sk_buff *skb)
2079 {
2080         if (skb->data[0] & 0x01)
2081                 *(u8 *)skb_push(skb, 1) = 0x00;
2082 }
2083
2084 /**
2085  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2086  * @skb: Socket buffer where protocol field should be decompressed. First byte
2087  *       of data must be a protocol field byte.
2088  *
2089  * Decompress protocol field in PPP header if it's compressed, e.g. when
2090  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2091  * sure that skb data room is sufficient for Protocol field, before and after
2092  * decompression.
2093  *
2094  * Return: true - decompressed successfully, false - not enough room in skb.
2095  */
2096 static bool ppp_decompress_proto(struct sk_buff *skb)
2097 {
2098         /* At least one byte should be present (if protocol is compressed) */
2099         if (!pskb_may_pull(skb, 1))
2100                 return false;
2101
2102         __ppp_decompress_proto(skb);
2103
2104         /* Protocol field should occupy 2 bytes when not compressed */
2105         return pskb_may_pull(skb, 2);
2106 }
2107
2108 void
2109 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2110 {
2111         struct channel *pch = chan->ppp;
2112         int proto;
2113
2114         if (!pch) {
2115                 kfree_skb(skb);
2116                 return;
2117         }
2118
2119         read_lock_bh(&pch->upl);
2120         if (!ppp_decompress_proto(skb)) {
2121                 kfree_skb(skb);
2122                 if (pch->ppp) {
2123                         ++pch->ppp->dev->stats.rx_length_errors;
2124                         ppp_receive_error(pch->ppp);
2125                 }
2126                 goto done;
2127         }
2128
2129         proto = PPP_PROTO(skb);
2130         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2131                 /* put it on the channel queue */
2132                 skb_queue_tail(&pch->file.rq, skb);
2133                 /* drop old frames if queue too long */
2134                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2135                        (skb = skb_dequeue(&pch->file.rq)))
2136                         kfree_skb(skb);
2137                 wake_up_interruptible(&pch->file.rwait);
2138         } else {
2139                 ppp_do_recv(pch->ppp, skb, pch);
2140         }
2141
2142 done:
2143         read_unlock_bh(&pch->upl);
2144 }
2145
2146 /* Put a 0-length skb in the receive queue as an error indication */
2147 void
2148 ppp_input_error(struct ppp_channel *chan, int code)
2149 {
2150         struct channel *pch = chan->ppp;
2151         struct sk_buff *skb;
2152
2153         if (!pch)
2154                 return;
2155
2156         read_lock_bh(&pch->upl);
2157         if (pch->ppp) {
2158                 skb = alloc_skb(0, GFP_ATOMIC);
2159                 if (skb) {
2160                         skb->len = 0;           /* probably unnecessary */
2161                         skb->cb[0] = code;
2162                         ppp_do_recv(pch->ppp, skb, pch);
2163                 }
2164         }
2165         read_unlock_bh(&pch->upl);
2166 }
2167
2168 /*
2169  * We come in here to process a received frame.
2170  * The receive side of the ppp unit is locked.
2171  */
2172 static void
2173 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2174 {
2175         /* note: a 0-length skb is used as an error indication */
2176         if (skb->len > 0) {
2177                 skb_checksum_complete_unset(skb);
2178 #ifdef CONFIG_PPP_MULTILINK
2179                 /* XXX do channel-level decompression here */
2180                 if (PPP_PROTO(skb) == PPP_MP)
2181                         ppp_receive_mp_frame(ppp, skb, pch);
2182                 else
2183 #endif /* CONFIG_PPP_MULTILINK */
2184                         ppp_receive_nonmp_frame(ppp, skb);
2185         } else {
2186                 kfree_skb(skb);
2187                 ppp_receive_error(ppp);
2188         }
2189 }
2190
2191 static void
2192 ppp_receive_error(struct ppp *ppp)
2193 {
2194         ++ppp->dev->stats.rx_errors;
2195         if (ppp->vj)
2196                 slhc_toss(ppp->vj);
2197 }
2198
2199 static void
2200 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2201 {
2202         struct sk_buff *ns;
2203         int proto, len, npi;
2204
2205         /*
2206          * Decompress the frame, if compressed.
2207          * Note that some decompressors need to see uncompressed frames
2208          * that come in as well as compressed frames.
2209          */
2210         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2211             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2212                 skb = ppp_decompress_frame(ppp, skb);
2213
2214         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2215                 goto err;
2216
2217         /* At this point the "Protocol" field MUST be decompressed, either in
2218          * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2219          */
2220         proto = PPP_PROTO(skb);
2221         switch (proto) {
2222         case PPP_VJC_COMP:
2223                 /* decompress VJ compressed packets */
2224                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2225                         goto err;
2226
2227                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2228                         /* copy to a new sk_buff with more tailroom */
2229                         ns = dev_alloc_skb(skb->len + 128);
2230                         if (!ns) {
2231                                 netdev_err(ppp->dev, "PPP: no memory "
2232                                            "(VJ decomp)\n");
2233                                 goto err;
2234                         }
2235                         skb_reserve(ns, 2);
2236                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2237                         consume_skb(skb);
2238                         skb = ns;
2239                 }
2240                 else
2241                         skb->ip_summed = CHECKSUM_NONE;
2242
2243                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2244                 if (len <= 0) {
2245                         netdev_printk(KERN_DEBUG, ppp->dev,
2246                                       "PPP: VJ decompression error\n");
2247                         goto err;
2248                 }
2249                 len += 2;
2250                 if (len > skb->len)
2251                         skb_put(skb, len - skb->len);
2252                 else if (len < skb->len)
2253                         skb_trim(skb, len);
2254                 proto = PPP_IP;
2255                 break;
2256
2257         case PPP_VJC_UNCOMP:
2258                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2259                         goto err;
2260
2261                 /* Until we fix the decompressor need to make sure
2262                  * data portion is linear.
2263                  */
2264                 if (!pskb_may_pull(skb, skb->len))
2265                         goto err;
2266
2267                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2268                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2269                         goto err;
2270                 }
2271                 proto = PPP_IP;
2272                 break;
2273
2274         case PPP_CCP:
2275                 ppp_ccp_peek(ppp, skb, 1);
2276                 break;
2277         }
2278
2279         ++ppp->stats64.rx_packets;
2280         ppp->stats64.rx_bytes += skb->len - 2;
2281
2282         npi = proto_to_npindex(proto);
2283         if (npi < 0) {
2284                 /* control or unknown frame - pass it to pppd */
2285                 skb_queue_tail(&ppp->file.rq, skb);
2286                 /* limit queue length by dropping old frames */
2287                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2288                        (skb = skb_dequeue(&ppp->file.rq)))
2289                         kfree_skb(skb);
2290                 /* wake up any process polling or blocking on read */
2291                 wake_up_interruptible(&ppp->file.rwait);
2292
2293         } else {
2294                 /* network protocol frame - give it to the kernel */
2295
2296 #ifdef CONFIG_PPP_FILTER
2297                 /* check if the packet passes the pass and active filters */
2298                 /* the filter instructions are constructed assuming
2299                    a four-byte PPP header on each packet */
2300                 if (ppp->pass_filter || ppp->active_filter) {
2301                         if (skb_unclone(skb, GFP_ATOMIC))
2302                                 goto err;
2303
2304                         *(u8 *)skb_push(skb, 2) = 0;
2305                         if (ppp->pass_filter &&
2306                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2307                                 if (ppp->debug & 1)
2308                                         netdev_printk(KERN_DEBUG, ppp->dev,
2309                                                       "PPP: inbound frame "
2310                                                       "not passed\n");
2311                                 kfree_skb(skb);
2312                                 return;
2313                         }
2314                         if (!(ppp->active_filter &&
2315                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2316                                 ppp->last_recv = jiffies;
2317                         __skb_pull(skb, 2);
2318                 } else
2319 #endif /* CONFIG_PPP_FILTER */
2320                         ppp->last_recv = jiffies;
2321
2322                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2323                     ppp->npmode[npi] != NPMODE_PASS) {
2324                         kfree_skb(skb);
2325                 } else {
2326                         /* chop off protocol */
2327                         skb_pull_rcsum(skb, 2);
2328                         skb->dev = ppp->dev;
2329                         skb->protocol = htons(npindex_to_ethertype[npi]);
2330                         skb_reset_mac_header(skb);
2331                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2332                                                       dev_net(ppp->dev)));
2333                         netif_rx(skb);
2334                 }
2335         }
2336         return;
2337
2338  err:
2339         kfree_skb(skb);
2340         ppp_receive_error(ppp);
2341 }
2342
2343 static struct sk_buff *
2344 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2345 {
2346         int proto = PPP_PROTO(skb);
2347         struct sk_buff *ns;
2348         int len;
2349
2350         /* Until we fix all the decompressor's need to make sure
2351          * data portion is linear.
2352          */
2353         if (!pskb_may_pull(skb, skb->len))
2354                 goto err;
2355
2356         if (proto == PPP_COMP) {
2357                 int obuff_size;
2358
2359                 switch(ppp->rcomp->compress_proto) {
2360                 case CI_MPPE:
2361                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2362                         break;
2363                 default:
2364                         obuff_size = ppp->mru + PPP_HDRLEN;
2365                         break;
2366                 }
2367
2368                 ns = dev_alloc_skb(obuff_size);
2369                 if (!ns) {
2370                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2371                                    "no memory\n");
2372                         goto err;
2373                 }
2374                 /* the decompressor still expects the A/C bytes in the hdr */
2375                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2376                                 skb->len + 2, ns->data, obuff_size);
2377                 if (len < 0) {
2378                         /* Pass the compressed frame to pppd as an
2379                            error indication. */
2380                         if (len == DECOMP_FATALERROR)
2381                                 ppp->rstate |= SC_DC_FERROR;
2382                         kfree_skb(ns);
2383                         goto err;
2384                 }
2385
2386                 consume_skb(skb);
2387                 skb = ns;
2388                 skb_put(skb, len);
2389                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2390
2391                 /* Don't call __ppp_decompress_proto() here, but instead rely on
2392                  * corresponding algo (mppe/bsd/deflate) to decompress it.
2393                  */
2394         } else {
2395                 /* Uncompressed frame - pass to decompressor so it
2396                    can update its dictionary if necessary. */
2397                 if (ppp->rcomp->incomp)
2398                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2399                                            skb->len + 2);
2400         }
2401
2402         return skb;
2403
2404  err:
2405         ppp->rstate |= SC_DC_ERROR;
2406         ppp_receive_error(ppp);
2407         return skb;
2408 }
2409
2410 #ifdef CONFIG_PPP_MULTILINK
2411 /*
2412  * Receive a multilink frame.
2413  * We put it on the reconstruction queue and then pull off
2414  * as many completed frames as we can.
2415  */
2416 static void
2417 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2418 {
2419         u32 mask, seq;
2420         struct channel *ch;
2421         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2422
2423         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2424                 goto err;               /* no good, throw it away */
2425
2426         /* Decode sequence number and begin/end bits */
2427         if (ppp->flags & SC_MP_SHORTSEQ) {
2428                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2429                 mask = 0xfff;
2430         } else {
2431                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2432                 mask = 0xffffff;
2433         }
2434         PPP_MP_CB(skb)->BEbits = skb->data[2];
2435         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2436
2437         /*
2438          * Do protocol ID decompression on the first fragment of each packet.
2439          * We have to do that here, because ppp_receive_nonmp_frame() expects
2440          * decompressed protocol field.
2441          */
2442         if (PPP_MP_CB(skb)->BEbits & B)
2443                 __ppp_decompress_proto(skb);
2444
2445         /*
2446          * Expand sequence number to 32 bits, making it as close
2447          * as possible to ppp->minseq.
2448          */
2449         seq |= ppp->minseq & ~mask;
2450         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2451                 seq += mask + 1;
2452         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2453                 seq -= mask + 1;        /* should never happen */
2454         PPP_MP_CB(skb)->sequence = seq;
2455         pch->lastseq = seq;
2456
2457         /*
2458          * If this packet comes before the next one we were expecting,
2459          * drop it.
2460          */
2461         if (seq_before(seq, ppp->nextseq)) {
2462                 kfree_skb(skb);
2463                 ++ppp->dev->stats.rx_dropped;
2464                 ppp_receive_error(ppp);
2465                 return;
2466         }
2467
2468         /*
2469          * Reevaluate minseq, the minimum over all channels of the
2470          * last sequence number received on each channel.  Because of
2471          * the increasing sequence number rule, we know that any fragment
2472          * before `minseq' which hasn't arrived is never going to arrive.
2473          * The list of channels can't change because we have the receive
2474          * side of the ppp unit locked.
2475          */
2476         list_for_each_entry(ch, &ppp->channels, clist) {
2477                 if (seq_before(ch->lastseq, seq))
2478                         seq = ch->lastseq;
2479         }
2480         if (seq_before(ppp->minseq, seq))
2481                 ppp->minseq = seq;
2482
2483         /* Put the fragment on the reconstruction queue */
2484         ppp_mp_insert(ppp, skb);
2485
2486         /* If the queue is getting long, don't wait any longer for packets
2487            before the start of the queue. */
2488         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2489                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2490                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2491                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2492         }
2493
2494         /* Pull completed packets off the queue and receive them. */
2495         while ((skb = ppp_mp_reconstruct(ppp))) {
2496                 if (pskb_may_pull(skb, 2))
2497                         ppp_receive_nonmp_frame(ppp, skb);
2498                 else {
2499                         ++ppp->dev->stats.rx_length_errors;
2500                         kfree_skb(skb);
2501                         ppp_receive_error(ppp);
2502                 }
2503         }
2504
2505         return;
2506
2507  err:
2508         kfree_skb(skb);
2509         ppp_receive_error(ppp);
2510 }
2511
2512 /*
2513  * Insert a fragment on the MP reconstruction queue.
2514  * The queue is ordered by increasing sequence number.
2515  */
2516 static void
2517 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2518 {
2519         struct sk_buff *p;
2520         struct sk_buff_head *list = &ppp->mrq;
2521         u32 seq = PPP_MP_CB(skb)->sequence;
2522
2523         /* N.B. we don't need to lock the list lock because we have the
2524            ppp unit receive-side lock. */
2525         skb_queue_walk(list, p) {
2526                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2527                         break;
2528         }
2529         __skb_queue_before(list, p, skb);
2530 }
2531
2532 /*
2533  * Reconstruct a packet from the MP fragment queue.
2534  * We go through increasing sequence numbers until we find a
2535  * complete packet, or we get to the sequence number for a fragment
2536  * which hasn't arrived but might still do so.
2537  */
2538 static struct sk_buff *
2539 ppp_mp_reconstruct(struct ppp *ppp)
2540 {
2541         u32 seq = ppp->nextseq;
2542         u32 minseq = ppp->minseq;
2543         struct sk_buff_head *list = &ppp->mrq;
2544         struct sk_buff *p, *tmp;
2545         struct sk_buff *head, *tail;
2546         struct sk_buff *skb = NULL;
2547         int lost = 0, len = 0;
2548
2549         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2550                 return NULL;
2551         head = __skb_peek(list);
2552         tail = NULL;
2553         skb_queue_walk_safe(list, p, tmp) {
2554         again:
2555                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2556                         /* this can't happen, anyway ignore the skb */
2557                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2558                                    "seq %u < %u\n",
2559                                    PPP_MP_CB(p)->sequence, seq);
2560                         __skb_unlink(p, list);
2561                         kfree_skb(p);
2562                         continue;
2563                 }
2564                 if (PPP_MP_CB(p)->sequence != seq) {
2565                         u32 oldseq;
2566                         /* Fragment `seq' is missing.  If it is after
2567                            minseq, it might arrive later, so stop here. */
2568                         if (seq_after(seq, minseq))
2569                                 break;
2570                         /* Fragment `seq' is lost, keep going. */
2571                         lost = 1;
2572                         oldseq = seq;
2573                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2574                                 minseq + 1: PPP_MP_CB(p)->sequence;
2575
2576                         if (ppp->debug & 1)
2577                                 netdev_printk(KERN_DEBUG, ppp->dev,
2578                                               "lost frag %u..%u\n",
2579                                               oldseq, seq-1);
2580
2581                         goto again;
2582                 }
2583
2584                 /*
2585                  * At this point we know that all the fragments from
2586                  * ppp->nextseq to seq are either present or lost.
2587                  * Also, there are no complete packets in the queue
2588                  * that have no missing fragments and end before this
2589                  * fragment.
2590                  */
2591
2592                 /* B bit set indicates this fragment starts a packet */
2593                 if (PPP_MP_CB(p)->BEbits & B) {
2594                         head = p;
2595                         lost = 0;
2596                         len = 0;
2597                 }
2598
2599                 len += p->len;
2600
2601                 /* Got a complete packet yet? */
2602                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2603                     (PPP_MP_CB(head)->BEbits & B)) {
2604                         if (len > ppp->mrru + 2) {
2605                                 ++ppp->dev->stats.rx_length_errors;
2606                                 netdev_printk(KERN_DEBUG, ppp->dev,
2607                                               "PPP: reconstructed packet"
2608                                               " is too long (%d)\n", len);
2609                         } else {
2610                                 tail = p;
2611                                 break;
2612                         }
2613                         ppp->nextseq = seq + 1;
2614                 }
2615
2616                 /*
2617                  * If this is the ending fragment of a packet,
2618                  * and we haven't found a complete valid packet yet,
2619                  * we can discard up to and including this fragment.
2620                  */
2621                 if (PPP_MP_CB(p)->BEbits & E) {
2622                         struct sk_buff *tmp2;
2623
2624                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2625                                 if (ppp->debug & 1)
2626                                         netdev_printk(KERN_DEBUG, ppp->dev,
2627                                                       "discarding frag %u\n",
2628                                                       PPP_MP_CB(p)->sequence);
2629                                 __skb_unlink(p, list);
2630                                 kfree_skb(p);
2631                         }
2632                         head = skb_peek(list);
2633                         if (!head)
2634                                 break;
2635                 }
2636                 ++seq;
2637         }
2638
2639         /* If we have a complete packet, copy it all into one skb. */
2640         if (tail != NULL) {
2641                 /* If we have discarded any fragments,
2642                    signal a receive error. */
2643                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2644                         skb_queue_walk_safe(list, p, tmp) {
2645                                 if (p == head)
2646                                         break;
2647                                 if (ppp->debug & 1)
2648                                         netdev_printk(KERN_DEBUG, ppp->dev,
2649                                                       "discarding frag %u\n",
2650                                                       PPP_MP_CB(p)->sequence);
2651                                 __skb_unlink(p, list);
2652                                 kfree_skb(p);
2653                         }
2654
2655                         if (ppp->debug & 1)
2656                                 netdev_printk(KERN_DEBUG, ppp->dev,
2657                                               "  missed pkts %u..%u\n",
2658                                               ppp->nextseq,
2659                                               PPP_MP_CB(head)->sequence-1);
2660                         ++ppp->dev->stats.rx_dropped;
2661                         ppp_receive_error(ppp);
2662                 }
2663
2664                 skb = head;
2665                 if (head != tail) {
2666                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2667                         p = skb_queue_next(list, head);
2668                         __skb_unlink(skb, list);
2669                         skb_queue_walk_from_safe(list, p, tmp) {
2670                                 __skb_unlink(p, list);
2671                                 *fragpp = p;
2672                                 p->next = NULL;
2673                                 fragpp = &p->next;
2674
2675                                 skb->len += p->len;
2676                                 skb->data_len += p->len;
2677                                 skb->truesize += p->truesize;
2678
2679                                 if (p == tail)
2680                                         break;
2681                         }
2682                 } else {
2683                         __skb_unlink(skb, list);
2684                 }
2685
2686                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2687         }
2688
2689         return skb;
2690 }
2691 #endif /* CONFIG_PPP_MULTILINK */
2692
2693 /*
2694  * Channel interface.
2695  */
2696
2697 /* Create a new, unattached ppp channel. */
2698 int ppp_register_channel(struct ppp_channel *chan)
2699 {
2700         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2701 }
2702
2703 /* Create a new, unattached ppp channel for specified net. */
2704 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2705 {
2706         struct channel *pch;
2707         struct ppp_net *pn;
2708
2709         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2710         if (!pch)
2711                 return -ENOMEM;
2712
2713         pn = ppp_pernet(net);
2714
2715         pch->ppp = NULL;
2716         pch->chan = chan;
2717         pch->chan_net = get_net(net);
2718         chan->ppp = pch;
2719         init_ppp_file(&pch->file, CHANNEL);
2720         pch->file.hdrlen = chan->hdrlen;
2721 #ifdef CONFIG_PPP_MULTILINK
2722         pch->lastseq = -1;
2723 #endif /* CONFIG_PPP_MULTILINK */
2724         init_rwsem(&pch->chan_sem);
2725         spin_lock_init(&pch->downl);
2726         rwlock_init(&pch->upl);
2727
2728         spin_lock_bh(&pn->all_channels_lock);
2729         pch->file.index = ++pn->last_channel_index;
2730         list_add(&pch->list, &pn->new_channels);
2731         atomic_inc(&channel_count);
2732         spin_unlock_bh(&pn->all_channels_lock);
2733
2734         return 0;
2735 }
2736
2737 /*
2738  * Return the index of a channel.
2739  */
2740 int ppp_channel_index(struct ppp_channel *chan)
2741 {
2742         struct channel *pch = chan->ppp;
2743
2744         if (pch)
2745                 return pch->file.index;
2746         return -1;
2747 }
2748
2749 /*
2750  * Return the PPP unit number to which a channel is connected.
2751  */
2752 int ppp_unit_number(struct ppp_channel *chan)
2753 {
2754         struct channel *pch = chan->ppp;
2755         int unit = -1;
2756
2757         if (pch) {
2758                 read_lock_bh(&pch->upl);
2759                 if (pch->ppp)
2760                         unit = pch->ppp->file.index;
2761                 read_unlock_bh(&pch->upl);
2762         }
2763         return unit;
2764 }
2765
2766 /*
2767  * Return the PPP device interface name of a channel.
2768  */
2769 char *ppp_dev_name(struct ppp_channel *chan)
2770 {
2771         struct channel *pch = chan->ppp;
2772         char *name = NULL;
2773
2774         if (pch) {
2775                 read_lock_bh(&pch->upl);
2776                 if (pch->ppp && pch->ppp->dev)
2777                         name = pch->ppp->dev->name;
2778                 read_unlock_bh(&pch->upl);
2779         }
2780         return name;
2781 }
2782
2783
2784 /*
2785  * Disconnect a channel from the generic layer.
2786  * This must be called in process context.
2787  */
2788 void
2789 ppp_unregister_channel(struct ppp_channel *chan)
2790 {
2791         struct channel *pch = chan->ppp;
2792         struct ppp_net *pn;
2793
2794         if (!pch)
2795                 return;         /* should never happen */
2796
2797         chan->ppp = NULL;
2798
2799         /*
2800          * This ensures that we have returned from any calls into the
2801          * the channel's start_xmit or ioctl routine before we proceed.
2802          */
2803         down_write(&pch->chan_sem);
2804         spin_lock_bh(&pch->downl);
2805         pch->chan = NULL;
2806         spin_unlock_bh(&pch->downl);
2807         up_write(&pch->chan_sem);
2808         ppp_disconnect_channel(pch);
2809
2810         pn = ppp_pernet(pch->chan_net);
2811         spin_lock_bh(&pn->all_channels_lock);
2812         list_del(&pch->list);
2813         spin_unlock_bh(&pn->all_channels_lock);
2814
2815         pch->file.dead = 1;
2816         wake_up_interruptible(&pch->file.rwait);
2817         if (refcount_dec_and_test(&pch->file.refcnt))
2818                 ppp_destroy_channel(pch);
2819 }
2820
2821 /*
2822  * Callback from a channel when it can accept more to transmit.
2823  * This should be called at BH/softirq level, not interrupt level.
2824  */
2825 void
2826 ppp_output_wakeup(struct ppp_channel *chan)
2827 {
2828         struct channel *pch = chan->ppp;
2829
2830         if (!pch)
2831                 return;
2832         ppp_channel_push(pch);
2833 }
2834
2835 /*
2836  * Compression control.
2837  */
2838
2839 /* Process the PPPIOCSCOMPRESS ioctl. */
2840 static int
2841 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
2842 {
2843         int err = -EFAULT;
2844         struct compressor *cp, *ocomp;
2845         void *state, *ostate;
2846         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2847
2848         if (data->length > CCP_MAX_OPTION_LENGTH)
2849                 goto out;
2850         if (copy_from_user(ccp_option, data->ptr, data->length))
2851                 goto out;
2852
2853         err = -EINVAL;
2854         if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
2855                 goto out;
2856
2857         cp = try_then_request_module(
2858                 find_compressor(ccp_option[0]),
2859                 "ppp-compress-%d", ccp_option[0]);
2860         if (!cp)
2861                 goto out;
2862
2863         err = -ENOBUFS;
2864         if (data->transmit) {
2865                 state = cp->comp_alloc(ccp_option, data->length);
2866                 if (state) {
2867                         ppp_xmit_lock(ppp);
2868                         ppp->xstate &= ~SC_COMP_RUN;
2869                         ocomp = ppp->xcomp;
2870                         ostate = ppp->xc_state;
2871                         ppp->xcomp = cp;
2872                         ppp->xc_state = state;
2873                         ppp_xmit_unlock(ppp);
2874                         if (ostate) {
2875                                 ocomp->comp_free(ostate);
2876                                 module_put(ocomp->owner);
2877                         }
2878                         err = 0;
2879                 } else
2880                         module_put(cp->owner);
2881
2882         } else {
2883                 state = cp->decomp_alloc(ccp_option, data->length);
2884                 if (state) {
2885                         ppp_recv_lock(ppp);
2886                         ppp->rstate &= ~SC_DECOMP_RUN;
2887                         ocomp = ppp->rcomp;
2888                         ostate = ppp->rc_state;
2889                         ppp->rcomp = cp;
2890                         ppp->rc_state = state;
2891                         ppp_recv_unlock(ppp);
2892                         if (ostate) {
2893                                 ocomp->decomp_free(ostate);
2894                                 module_put(ocomp->owner);
2895                         }
2896                         err = 0;
2897                 } else
2898                         module_put(cp->owner);
2899         }
2900
2901  out:
2902         return err;
2903 }
2904
2905 /*
2906  * Look at a CCP packet and update our state accordingly.
2907  * We assume the caller has the xmit or recv path locked.
2908  */
2909 static void
2910 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2911 {
2912         unsigned char *dp;
2913         int len;
2914
2915         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2916                 return; /* no header */
2917         dp = skb->data + 2;
2918
2919         switch (CCP_CODE(dp)) {
2920         case CCP_CONFREQ:
2921
2922                 /* A ConfReq starts negotiation of compression
2923                  * in one direction of transmission,
2924                  * and hence brings it down...but which way?
2925                  *
2926                  * Remember:
2927                  * A ConfReq indicates what the sender would like to receive
2928                  */
2929                 if(inbound)
2930                         /* He is proposing what I should send */
2931                         ppp->xstate &= ~SC_COMP_RUN;
2932                 else
2933                         /* I am proposing to what he should send */
2934                         ppp->rstate &= ~SC_DECOMP_RUN;
2935
2936                 break;
2937
2938         case CCP_TERMREQ:
2939         case CCP_TERMACK:
2940                 /*
2941                  * CCP is going down, both directions of transmission
2942                  */
2943                 ppp->rstate &= ~SC_DECOMP_RUN;
2944                 ppp->xstate &= ~SC_COMP_RUN;
2945                 break;
2946
2947         case CCP_CONFACK:
2948                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2949                         break;
2950                 len = CCP_LENGTH(dp);
2951                 if (!pskb_may_pull(skb, len + 2))
2952                         return;         /* too short */
2953                 dp += CCP_HDRLEN;
2954                 len -= CCP_HDRLEN;
2955                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2956                         break;
2957                 if (inbound) {
2958                         /* we will start receiving compressed packets */
2959                         if (!ppp->rc_state)
2960                                 break;
2961                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2962                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2963                                 ppp->rstate |= SC_DECOMP_RUN;
2964                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2965                         }
2966                 } else {
2967                         /* we will soon start sending compressed packets */
2968                         if (!ppp->xc_state)
2969                                 break;
2970                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2971                                         ppp->file.index, 0, ppp->debug))
2972                                 ppp->xstate |= SC_COMP_RUN;
2973                 }
2974                 break;
2975
2976         case CCP_RESETACK:
2977                 /* reset the [de]compressor */
2978                 if ((ppp->flags & SC_CCP_UP) == 0)
2979                         break;
2980                 if (inbound) {
2981                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2982                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2983                                 ppp->rstate &= ~SC_DC_ERROR;
2984                         }
2985                 } else {
2986                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2987                                 ppp->xcomp->comp_reset(ppp->xc_state);
2988                 }
2989                 break;
2990         }
2991 }
2992
2993 /* Free up compression resources. */
2994 static void
2995 ppp_ccp_closed(struct ppp *ppp)
2996 {
2997         void *xstate, *rstate;
2998         struct compressor *xcomp, *rcomp;
2999
3000         ppp_lock(ppp);
3001         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3002         ppp->xstate = 0;
3003         xcomp = ppp->xcomp;
3004         xstate = ppp->xc_state;
3005         ppp->xc_state = NULL;
3006         ppp->rstate = 0;
3007         rcomp = ppp->rcomp;
3008         rstate = ppp->rc_state;
3009         ppp->rc_state = NULL;
3010         ppp_unlock(ppp);
3011
3012         if (xstate) {
3013                 xcomp->comp_free(xstate);
3014                 module_put(xcomp->owner);
3015         }
3016         if (rstate) {
3017                 rcomp->decomp_free(rstate);
3018                 module_put(rcomp->owner);
3019         }
3020 }
3021
3022 /* List of compressors. */
3023 static LIST_HEAD(compressor_list);
3024 static DEFINE_SPINLOCK(compressor_list_lock);
3025
3026 struct compressor_entry {
3027         struct list_head list;
3028         struct compressor *comp;
3029 };
3030
3031 static struct compressor_entry *
3032 find_comp_entry(int proto)
3033 {
3034         struct compressor_entry *ce;
3035
3036         list_for_each_entry(ce, &compressor_list, list) {
3037                 if (ce->comp->compress_proto == proto)
3038                         return ce;
3039         }
3040         return NULL;
3041 }
3042
3043 /* Register a compressor */
3044 int
3045 ppp_register_compressor(struct compressor *cp)
3046 {
3047         struct compressor_entry *ce;
3048         int ret;
3049         spin_lock(&compressor_list_lock);
3050         ret = -EEXIST;
3051         if (find_comp_entry(cp->compress_proto))
3052                 goto out;
3053         ret = -ENOMEM;
3054         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3055         if (!ce)
3056                 goto out;
3057         ret = 0;
3058         ce->comp = cp;
3059         list_add(&ce->list, &compressor_list);
3060  out:
3061         spin_unlock(&compressor_list_lock);
3062         return ret;
3063 }
3064
3065 /* Unregister a compressor */
3066 void
3067 ppp_unregister_compressor(struct compressor *cp)
3068 {
3069         struct compressor_entry *ce;
3070
3071         spin_lock(&compressor_list_lock);
3072         ce = find_comp_entry(cp->compress_proto);
3073         if (ce && ce->comp == cp) {
3074                 list_del(&ce->list);
3075                 kfree(ce);
3076         }
3077         spin_unlock(&compressor_list_lock);
3078 }
3079
3080 /* Find a compressor. */
3081 static struct compressor *
3082 find_compressor(int type)
3083 {
3084         struct compressor_entry *ce;
3085         struct compressor *cp = NULL;
3086
3087         spin_lock(&compressor_list_lock);
3088         ce = find_comp_entry(type);
3089         if (ce) {
3090                 cp = ce->comp;
3091                 if (!try_module_get(cp->owner))
3092                         cp = NULL;
3093         }
3094         spin_unlock(&compressor_list_lock);
3095         return cp;
3096 }
3097
3098 /*
3099  * Miscelleneous stuff.
3100  */
3101
3102 static void
3103 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3104 {
3105         struct slcompress *vj = ppp->vj;
3106
3107         memset(st, 0, sizeof(*st));
3108         st->p.ppp_ipackets = ppp->stats64.rx_packets;
3109         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3110         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3111         st->p.ppp_opackets = ppp->stats64.tx_packets;
3112         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3113         st->p.ppp_obytes = ppp->stats64.tx_bytes;
3114         if (!vj)
3115                 return;
3116         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3117         st->vj.vjs_compressed = vj->sls_o_compressed;
3118         st->vj.vjs_searches = vj->sls_o_searches;
3119         st->vj.vjs_misses = vj->sls_o_misses;
3120         st->vj.vjs_errorin = vj->sls_i_error;
3121         st->vj.vjs_tossed = vj->sls_i_tossed;
3122         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3123         st->vj.vjs_compressedin = vj->sls_i_compressed;
3124 }
3125
3126 /*
3127  * Stuff for handling the lists of ppp units and channels
3128  * and for initialization.
3129  */
3130
3131 /*
3132  * Create a new ppp interface unit.  Fails if it can't allocate memory
3133  * or if there is already a unit with the requested number.
3134  * unit == -1 means allocate a new number.
3135  */
3136 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3137 {
3138         struct ppp_config conf = {
3139                 .file = file,
3140                 .unit = *unit,
3141                 .ifname_is_set = false,
3142         };
3143         struct net_device *dev;
3144         struct ppp *ppp;
3145         int err;
3146
3147         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3148         if (!dev) {
3149                 err = -ENOMEM;
3150                 goto err;
3151         }
3152         dev_net_set(dev, net);
3153         dev->rtnl_link_ops = &ppp_link_ops;
3154
3155         rtnl_lock();
3156
3157         err = ppp_dev_configure(net, dev, &conf);
3158         if (err < 0)
3159                 goto err_dev;
3160         ppp = netdev_priv(dev);
3161         *unit = ppp->file.index;
3162
3163         rtnl_unlock();
3164
3165         return 0;
3166
3167 err_dev:
3168         rtnl_unlock();
3169         free_netdev(dev);
3170 err:
3171         return err;
3172 }
3173
3174 /*
3175  * Initialize a ppp_file structure.
3176  */
3177 static void
3178 init_ppp_file(struct ppp_file *pf, int kind)
3179 {
3180         pf->kind = kind;
3181         skb_queue_head_init(&pf->xq);
3182         skb_queue_head_init(&pf->rq);
3183         refcount_set(&pf->refcnt, 1);
3184         init_waitqueue_head(&pf->rwait);
3185 }
3186
3187 /*
3188  * Free the memory used by a ppp unit.  This is only called once
3189  * there are no channels connected to the unit and no file structs
3190  * that reference the unit.
3191  */
3192 static void ppp_destroy_interface(struct ppp *ppp)
3193 {
3194         atomic_dec(&ppp_unit_count);
3195
3196         if (!ppp->file.dead || ppp->n_channels) {
3197                 /* "can't happen" */
3198                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3199                            "but dead=%d n_channels=%d !\n",
3200                            ppp, ppp->file.dead, ppp->n_channels);
3201                 return;
3202         }
3203
3204         ppp_ccp_closed(ppp);
3205         if (ppp->vj) {
3206                 slhc_free(ppp->vj);
3207                 ppp->vj = NULL;
3208         }
3209         skb_queue_purge(&ppp->file.xq);
3210         skb_queue_purge(&ppp->file.rq);
3211 #ifdef CONFIG_PPP_MULTILINK
3212         skb_queue_purge(&ppp->mrq);
3213 #endif /* CONFIG_PPP_MULTILINK */
3214 #ifdef CONFIG_PPP_FILTER
3215         if (ppp->pass_filter) {
3216                 bpf_prog_destroy(ppp->pass_filter);
3217                 ppp->pass_filter = NULL;
3218         }
3219
3220         if (ppp->active_filter) {
3221                 bpf_prog_destroy(ppp->active_filter);
3222                 ppp->active_filter = NULL;
3223         }
3224 #endif /* CONFIG_PPP_FILTER */
3225
3226         kfree_skb(ppp->xmit_pending);
3227         free_percpu(ppp->xmit_recursion);
3228
3229         free_netdev(ppp->dev);
3230 }
3231
3232 /*
3233  * Locate an existing ppp unit.
3234  * The caller should have locked the all_ppp_mutex.
3235  */
3236 static struct ppp *
3237 ppp_find_unit(struct ppp_net *pn, int unit)
3238 {
3239         return unit_find(&pn->units_idr, unit);
3240 }
3241
3242 /*
3243  * Locate an existing ppp channel.
3244  * The caller should have locked the all_channels_lock.
3245  * First we look in the new_channels list, then in the
3246  * all_channels list.  If found in the new_channels list,
3247  * we move it to the all_channels list.  This is for speed
3248  * when we have a lot of channels in use.
3249  */
3250 static struct channel *
3251 ppp_find_channel(struct ppp_net *pn, int unit)
3252 {
3253         struct channel *pch;
3254
3255         list_for_each_entry(pch, &pn->new_channels, list) {
3256                 if (pch->file.index == unit) {
3257                         list_move(&pch->list, &pn->all_channels);
3258                         return pch;
3259                 }
3260         }
3261
3262         list_for_each_entry(pch, &pn->all_channels, list) {
3263                 if (pch->file.index == unit)
3264                         return pch;
3265         }
3266
3267         return NULL;
3268 }
3269
3270 /*
3271  * Connect a PPP channel to a PPP interface unit.
3272  */
3273 static int
3274 ppp_connect_channel(struct channel *pch, int unit)
3275 {
3276         struct ppp *ppp;
3277         struct ppp_net *pn;
3278         int ret = -ENXIO;
3279         int hdrlen;
3280
3281         pn = ppp_pernet(pch->chan_net);
3282
3283         mutex_lock(&pn->all_ppp_mutex);
3284         ppp = ppp_find_unit(pn, unit);
3285         if (!ppp)
3286                 goto out;
3287         write_lock_bh(&pch->upl);
3288         ret = -EINVAL;
3289         if (pch->ppp)
3290                 goto outl;
3291
3292         ppp_lock(ppp);
3293         spin_lock_bh(&pch->downl);
3294         if (!pch->chan) {
3295                 /* Don't connect unregistered channels */
3296                 spin_unlock_bh(&pch->downl);
3297                 ppp_unlock(ppp);
3298                 ret = -ENOTCONN;
3299                 goto outl;
3300         }
3301         spin_unlock_bh(&pch->downl);
3302         if (pch->file.hdrlen > ppp->file.hdrlen)
3303                 ppp->file.hdrlen = pch->file.hdrlen;
3304         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3305         if (hdrlen > ppp->dev->hard_header_len)
3306                 ppp->dev->hard_header_len = hdrlen;
3307         list_add_tail(&pch->clist, &ppp->channels);
3308         ++ppp->n_channels;
3309         pch->ppp = ppp;
3310         refcount_inc(&ppp->file.refcnt);
3311         ppp_unlock(ppp);
3312         ret = 0;
3313
3314  outl:
3315         write_unlock_bh(&pch->upl);
3316  out:
3317         mutex_unlock(&pn->all_ppp_mutex);
3318         return ret;
3319 }
3320
3321 /*
3322  * Disconnect a channel from its ppp unit.
3323  */
3324 static int
3325 ppp_disconnect_channel(struct channel *pch)
3326 {
3327         struct ppp *ppp;
3328         int err = -EINVAL;
3329
3330         write_lock_bh(&pch->upl);
3331         ppp = pch->ppp;
3332         pch->ppp = NULL;
3333         write_unlock_bh(&pch->upl);
3334         if (ppp) {
3335                 /* remove it from the ppp unit's list */
3336                 ppp_lock(ppp);
3337                 list_del(&pch->clist);
3338                 if (--ppp->n_channels == 0)
3339                         wake_up_interruptible(&ppp->file.rwait);
3340                 ppp_unlock(ppp);
3341                 if (refcount_dec_and_test(&ppp->file.refcnt))
3342                         ppp_destroy_interface(ppp);
3343                 err = 0;
3344         }
3345         return err;
3346 }
3347
3348 /*
3349  * Free up the resources used by a ppp channel.
3350  */
3351 static void ppp_destroy_channel(struct channel *pch)
3352 {
3353         put_net(pch->chan_net);
3354         pch->chan_net = NULL;
3355
3356         atomic_dec(&channel_count);
3357
3358         if (!pch->file.dead) {
3359                 /* "can't happen" */
3360                 pr_err("ppp: destroying undead channel %p !\n", pch);
3361                 return;
3362         }
3363         skb_queue_purge(&pch->file.xq);
3364         skb_queue_purge(&pch->file.rq);
3365         kfree(pch);
3366 }
3367
3368 static void __exit ppp_cleanup(void)
3369 {
3370         /* should never happen */
3371         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3372                 pr_err("PPP: removing module but units remain!\n");
3373         rtnl_link_unregister(&ppp_link_ops);
3374         unregister_chrdev(PPP_MAJOR, "ppp");
3375         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3376         class_destroy(ppp_class);
3377         unregister_pernet_device(&ppp_net_ops);
3378 }
3379
3380 /*
3381  * Units handling. Caller must protect concurrent access
3382  * by holding all_ppp_mutex
3383  */
3384
3385 /* associate pointer with specified number */
3386 static int unit_set(struct idr *p, void *ptr, int n)
3387 {
3388         int unit;
3389
3390         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3391         if (unit == -ENOSPC)
3392                 unit = -EINVAL;
3393         return unit;
3394 }
3395
3396 /* get new free unit number and associate pointer with it */
3397 static int unit_get(struct idr *p, void *ptr, int min)
3398 {
3399         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3400 }
3401
3402 /* put unit number back to a pool */
3403 static void unit_put(struct idr *p, int n)
3404 {
3405         idr_remove(p, n);
3406 }
3407
3408 /* get pointer associated with the number */
3409 static void *unit_find(struct idr *p, int n)
3410 {
3411         return idr_find(p, n);
3412 }
3413
3414 /* Module/initialization stuff */
3415
3416 module_init(ppp_init);
3417 module_exit(ppp_cleanup);
3418
3419 EXPORT_SYMBOL(ppp_register_net_channel);
3420 EXPORT_SYMBOL(ppp_register_channel);
3421 EXPORT_SYMBOL(ppp_unregister_channel);
3422 EXPORT_SYMBOL(ppp_channel_index);
3423 EXPORT_SYMBOL(ppp_unit_number);
3424 EXPORT_SYMBOL(ppp_dev_name);
3425 EXPORT_SYMBOL(ppp_input);
3426 EXPORT_SYMBOL(ppp_input_error);
3427 EXPORT_SYMBOL(ppp_output_wakeup);
3428 EXPORT_SYMBOL(ppp_register_compressor);
3429 EXPORT_SYMBOL(ppp_unregister_compressor);
3430 MODULE_LICENSE("GPL");
3431 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3432 MODULE_ALIAS_RTNL_LINK("ppp");
3433 MODULE_ALIAS("devname:ppp");