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