drivers/net/ppp/ppp_generic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic PPP layer for Linux.
   4  *
   5  * Copyright 1999-2002 Paul Mackerras.
   6  *
   7  * The generic PPP layer handles the PPP network interfaces, the
   8  * /dev/ppp device, packet and VJ compression, and multilink.
   9  * It talks to PPP `channels' via the interface defined in
  10  * include/linux/ppp_channel.h.  Channels provide the basic means for
  11  * sending and receiving PPP frames on some kind of communications
  12  * channel.
  13  *
  14  * Part of the code in this driver was inspired by the old async-only
  15  * PPP driver, written by Michael Callahan and Al Longyear, and
  16  * subsequently hacked by Paul Mackerras.
  17  *
  18  * ==FILEVERSION 20041108==
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched/signal.h>
  24 #include <linux/kmod.h>
  25 #include <linux/init.h>
  26 #include <linux/list.h>
  27 #include <linux/idr.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/poll.h>
  30 #include <linux/ppp_defs.h>
  31 #include <linux/filter.h>
  32 #include <linux/ppp-ioctl.h>
  33 #include <linux/ppp_channel.h>
  34 #include <linux/ppp-comp.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/rtnetlink.h>
  37 #include <linux/if_arp.h>
  38 #include <linux/ip.h>
  39 #include <linux/tcp.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/rwsem.h>
  42 #include <linux/stddef.h>
  43 #include <linux/device.h>
  44 #include <linux/mutex.h>
  45 #include <linux/slab.h>
  46 #include <linux/file.h>
  47 #include <asm/unaligned.h>
  48 #include <net/slhc_vj.h>
  49 #include <linux/atomic.h>
  50 #include <linux/refcount.h>
  51
  52 #include <linux/nsproxy.h>
  53 #include <net/net_namespace.h>
  54 #include <net/netns/generic.h>
  55
  56 #define PPP_VERSION     "2.4.2"
  57
  58 /*
  59  * Network protocols we support.
  60  */
  61 #define NP_IP   0               /* Internet Protocol V4 */
  62 #define NP_IPV6 1               /* Internet Protocol V6 */
  63 #define NP_IPX  2               /* IPX protocol */
  64 #define NP_AT   3               /* Appletalk protocol */
  65 #define NP_MPLS_UC 4            /* MPLS unicast */
  66 #define NP_MPLS_MC 5            /* MPLS multicast */
  67 #define NUM_NP  6               /* Number of NPs. */
  68
  69 #define MPHDRLEN        6       /* multilink protocol header length */
  70 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  71
  72 #define PPP_PROTO_LEN   2
  73
  74 /*
  75  * An instance of /dev/ppp can be associated with either a ppp
  76  * interface unit or a ppp channel.  In both cases, file->private_data
  77  * points to one of these.
  78  */
  79 struct ppp_file {
  80         enum {
  81                 INTERFACE=1, CHANNEL
  82         }               kind;
  83         struct sk_buff_head xq;         /* pppd transmit queue */
  84         struct sk_buff_head rq;         /* receive queue for pppd */
  85         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  86         refcount_t      refcnt;         /* # refs (incl /dev/ppp attached) */
  87         int             hdrlen;         /* space to leave for headers */
  88         int             index;          /* interface unit / channel number */
  89         int             dead;           /* unit/channel has been shut down */
  90 };
  91
  92 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  93
  94 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  95 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  96
  97 /*
  98  * Data structure to hold primary network stats for which
  99  * we want to use 64 bit storage.  Other network stats
 100  * are stored in dev->stats of the ppp strucute.
 101  */
 102 struct ppp_link_stats {
 103         u64 rx_packets;
 104         u64 tx_packets;
 105         u64 rx_bytes;
 106         u64 tx_bytes;
 107 };
 108
 109 /*
 110  * Data structure describing one ppp unit.
 111  * A ppp unit corresponds to a ppp network interface device
 112  * and represents a multilink bundle.
 113  * It can have 0 or more ppp channels connected to it.
 114  */
 115 struct ppp {
 116         struct ppp_file file;           /* stuff for read/write/poll 0 */
 117         struct file     *owner;         /* file that owns this unit 48 */
 118         struct list_head channels;      /* list of attached channels 4c */
 119         int             n_channels;     /* how many channels are attached 54 */
 120         spinlock_t      rlock;          /* lock for receive side 58 */
 121         spinlock_t      wlock;          /* lock for transmit side 5c */
 122         int __percpu    *xmit_recursion; /* xmit recursion detect */
 123         int             mru;            /* max receive unit 60 */
 124         unsigned int    flags;          /* control bits 64 */
 125         unsigned int    xstate;         /* transmit state bits 68 */
 126         unsigned int    rstate;         /* receive state bits 6c */
 127         int             debug;          /* debug flags 70 */
 128         struct slcompress *vj;          /* state for VJ header compression */
 129         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 130         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 131         struct compressor *xcomp;       /* transmit packet compressor 8c */
 132         void            *xc_state;      /* its internal state 90 */
 133         struct compressor *rcomp;       /* receive decompressor 94 */
 134         void            *rc_state;      /* its internal state 98 */
 135         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 136         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 137         struct net_device *dev;         /* network interface device a4 */
 138         int             closing;        /* is device closing down? a8 */
 139 #ifdef CONFIG_PPP_MULTILINK
 140         int             nxchan;         /* next channel to send something on */
 141         u32             nxseq;          /* next sequence number to send */
 142         int             mrru;           /* MP: max reconst. receive unit */
 143         u32             nextseq;        /* MP: seq no of next packet */
 144         u32             minseq;         /* MP: min of most recent seqnos */
 145         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 146 #endif /* CONFIG_PPP_MULTILINK */
 147 #ifdef CONFIG_PPP_FILTER
 148         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 149         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 150 #endif /* CONFIG_PPP_FILTER */
 151         struct net      *ppp_net;       /* the net we belong to */
 152         struct ppp_link_stats stats64;  /* 64 bit network stats */
 153 };
 154
 155 /*
 156  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 157  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 158  * SC_MUST_COMP
 159  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 160  * Bits in xstate: SC_COMP_RUN
 161  */
 162 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 163                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 164                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 165
 166 /*
 167  * Private data structure for each channel.
 168  * This includes the data structure used for multilink.
 169  */
 170 struct channel {
 171         struct ppp_file file;           /* stuff for read/write/poll */
 172         struct list_head list;          /* link in all/new_channels list */
 173         struct ppp_channel *chan;       /* public channel data structure */
 174         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 175         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 176         struct ppp      *ppp;           /* ppp unit we're connected to */
 177         struct net      *chan_net;      /* the net channel belongs to */
 178         struct list_head clist;         /* link in list of channels per unit */
 179         rwlock_t        upl;            /* protects `ppp' */
 180 #ifdef CONFIG_PPP_MULTILINK
 181         u8              avail;          /* flag used in multilink stuff */
 182         u8              had_frag;       /* >= 1 fragments have been sent */
 183         u32             lastseq;        /* MP: last sequence # received */
 184         int             speed;          /* speed of the corresponding ppp channel*/
 185 #endif /* CONFIG_PPP_MULTILINK */
 186 };
 187
 188 struct ppp_config {
 189         struct file *file;
 190         s32 unit;
 191         bool ifname_is_set;
 192 };
 193
 194 /*
 195  * SMP locking issues:
 196  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 197  * list and the ppp.n_channels field, you need to take both locks
 198  * before you modify them.
 199  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 200  * channel.downl.
 201  */
 202
 203 static DEFINE_MUTEX(ppp_mutex);
 204 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 205 static atomic_t channel_count = ATOMIC_INIT(0);
 206
 207 /* per-net private data for this module */
 208 static unsigned int ppp_net_id __read_mostly;
 209 struct ppp_net {
 210         /* units to ppp mapping */
 211         struct idr units_idr;
 212
 213         /*
 214          * all_ppp_mutex protects the units_idr mapping.
 215          * It also ensures that finding a ppp unit in the units_idr
 216          * map and updating its file.refcnt field is atomic.
 217          */
 218         struct mutex all_ppp_mutex;
 219
 220         /* channels */
 221         struct list_head all_channels;
 222         struct list_head new_channels;
 223         int last_channel_index;
 224
 225         /*
 226          * all_channels_lock protects all_channels and
 227          * last_channel_index, and the atomicity of find
 228          * a channel and updating its file.refcnt field.
 229          */
 230         spinlock_t all_channels_lock;
 231 };
 232
 233 /* Get the PPP protocol number from a skb */
 234 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 235
 236 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 237 #define PPP_MAX_RQLEN   32
 238
 239 /*
 240  * Maximum number of multilink fragments queued up.
 241  * This has to be large enough to cope with the maximum latency of
 242  * the slowest channel relative to the others.  Strictly it should
 243  * depend on the number of channels and their characteristics.
 244  */
 245 #define PPP_MP_MAX_QLEN 128
 246
 247 /* Multilink header bits. */
 248 #define B       0x80            /* this fragment begins a packet */
 249 #define E       0x40            /* this fragment ends a packet */
 250
 251 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 252 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 253 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 254
 255 /* Prototypes. */
 256 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 257                         struct file *file, unsigned int cmd, unsigned long arg);
 258 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 259 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 260 static void ppp_push(struct ppp *ppp);
 261 static void ppp_channel_push(struct channel *pch);
 262 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 263                               struct channel *pch);
 264 static void ppp_receive_error(struct ppp *ppp);
 265 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 266 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 267                                             struct sk_buff *skb);
 268 #ifdef CONFIG_PPP_MULTILINK
 269 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 270                                 struct channel *pch);
 271 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 272 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 273 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 274 #endif /* CONFIG_PPP_MULTILINK */
 275 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
 276 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 277 static void ppp_ccp_closed(struct ppp *ppp);
 278 static struct compressor *find_compressor(int type);
 279 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 280 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 281 static void init_ppp_file(struct ppp_file *pf, int kind);
 282 static void ppp_destroy_interface(struct ppp *ppp);
 283 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 284 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 285 static int ppp_connect_channel(struct channel *pch, int unit);
 286 static int ppp_disconnect_channel(struct channel *pch);
 287 static void ppp_destroy_channel(struct channel *pch);
 288 static int unit_get(struct idr *p, void *ptr, int min);
 289 static int unit_set(struct idr *p, void *ptr, int n);
 290 static void unit_put(struct idr *p, int n);
 291 static void *unit_find(struct idr *p, int n);
 292 static void ppp_setup(struct net_device *dev);
 293
 294 static const struct net_device_ops ppp_netdev_ops;
 295
 296 static struct class *ppp_class;
 297
 298 /* per net-namespace data */
 299 static inline struct ppp_net *ppp_pernet(struct net *net)
 300 {
 301         return net_generic(net, ppp_net_id);
 302 }
 303
 304 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 305 static inline int proto_to_npindex(int proto)
 306 {
 307         switch (proto) {
 308         case PPP_IP:
 309                 return NP_IP;
 310         case PPP_IPV6:
 311                 return NP_IPV6;
 312         case PPP_IPX:
 313                 return NP_IPX;
 314         case PPP_AT:
 315                 return NP_AT;
 316         case PPP_MPLS_UC:
 317                 return NP_MPLS_UC;
 318         case PPP_MPLS_MC:
 319                 return NP_MPLS_MC;
 320         }
 321         return -EINVAL;
 322 }
 323
 324 /* Translates an NP index into a PPP protocol number */
 325 static const int npindex_to_proto[NUM_NP] = {
 326         PPP_IP,
 327         PPP_IPV6,
 328         PPP_IPX,
 329         PPP_AT,
 330         PPP_MPLS_UC,
 331         PPP_MPLS_MC,
 332 };
 333
 334 /* Translates an ethertype into an NP index */
 335 static inline int ethertype_to_npindex(int ethertype)
 336 {
 337         switch (ethertype) {
 338         case ETH_P_IP:
 339                 return NP_IP;
 340         case ETH_P_IPV6:
 341                 return NP_IPV6;
 342         case ETH_P_IPX:
 343                 return NP_IPX;
 344         case ETH_P_PPPTALK:
 345         case ETH_P_ATALK:
 346                 return NP_AT;
 347         case ETH_P_MPLS_UC:
 348                 return NP_MPLS_UC;
 349         case ETH_P_MPLS_MC:
 350                 return NP_MPLS_MC;
 351         }
 352         return -1;
 353 }
 354
 355 /* Translates an NP index into an ethertype */
 356 static const int npindex_to_ethertype[NUM_NP] = {
 357         ETH_P_IP,
 358         ETH_P_IPV6,
 359         ETH_P_IPX,
 360         ETH_P_PPPTALK,
 361         ETH_P_MPLS_UC,
 362         ETH_P_MPLS_MC,
 363 };
 364
 365 /*
 366  * Locking shorthand.
 367  */
 368 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 369 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 370 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 371 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 372 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 373                                      ppp_recv_lock(ppp); } while (0)
 374 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 375                                      ppp_xmit_unlock(ppp); } while (0)
 376
 377 /*
 378  * /dev/ppp device routines.
 379  * The /dev/ppp device is used by pppd to control the ppp unit.
 380  * It supports the read, write, ioctl and poll functions.
 381  * Open instances of /dev/ppp can be in one of three states:
 382  * unattached, attached to a ppp unit, or attached to a ppp channel.
 383  */
 384 static int ppp_open(struct inode *inode, struct file *file)
 385 {
 386         /*
 387          * This could (should?) be enforced by the permissions on /dev/ppp.
 388          */
 389         if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
 390                 return -EPERM;
 391         return 0;
 392 }
 393
 394 static int ppp_release(struct inode *unused, struct file *file)
 395 {
 396         struct ppp_file *pf = file->private_data;
 397         struct ppp *ppp;
 398
 399         if (pf) {
 400                 file->private_data = NULL;
 401                 if (pf->kind == INTERFACE) {
 402                         ppp = PF_TO_PPP(pf);
 403                         rtnl_lock();
 404                         if (file == ppp->owner)
 405                                 unregister_netdevice(ppp->dev);
 406                         rtnl_unlock();
 407                 }
 408                 if (refcount_dec_and_test(&pf->refcnt)) {
 409                         switch (pf->kind) {
 410                         case INTERFACE:
 411                                 ppp_destroy_interface(PF_TO_PPP(pf));
 412                                 break;
 413                         case CHANNEL:
 414                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 415                                 break;
 416                         }
 417                 }
 418         }
 419         return 0;
 420 }
 421
 422 static ssize_t ppp_read(struct file *file, char __user *buf,
 423                         size_t count, loff_t *ppos)
 424 {
 425         struct ppp_file *pf = file->private_data;
 426         DECLARE_WAITQUEUE(wait, current);
 427         ssize_t ret;
 428         struct sk_buff *skb = NULL;
 429         struct iovec iov;
 430         struct iov_iter to;
 431
 432         ret = count;
 433
 434         if (!pf)
 435                 return -ENXIO;
 436         add_wait_queue(&pf->rwait, &wait);
 437         for (;;) {
 438                 set_current_state(TASK_INTERRUPTIBLE);
 439                 skb = skb_dequeue(&pf->rq);
 440                 if (skb)
 441                         break;
 442                 ret = 0;
 443                 if (pf->dead)
 444                         break;
 445                 if (pf->kind == INTERFACE) {
 446                         /*
 447                          * Return 0 (EOF) on an interface that has no
 448                          * channels connected, unless it is looping
 449                          * network traffic (demand mode).
 450                          */
 451                         struct ppp *ppp = PF_TO_PPP(pf);
 452
 453                         ppp_recv_lock(ppp);
 454                         if (ppp->n_channels == 0 &&
 455                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 456                                 ppp_recv_unlock(ppp);
 457                                 break;
 458                         }
 459                         ppp_recv_unlock(ppp);
 460                 }
 461                 ret = -EAGAIN;
 462                 if (file->f_flags & O_NONBLOCK)
 463                         break;
 464                 ret = -ERESTARTSYS;
 465                 if (signal_pending(current))
 466                         break;
 467                 schedule();
 468         }
 469         set_current_state(TASK_RUNNING);
 470         remove_wait_queue(&pf->rwait, &wait);
 471
 472         if (!skb)
 473                 goto out;
 474
 475         ret = -EOVERFLOW;
 476         if (skb->len > count)
 477                 goto outf;
 478         ret = -EFAULT;
 479         iov.iov_base = buf;
 480         iov.iov_len = count;
 481         iov_iter_init(&to, READ, &iov, 1, count);
 482         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 483                 goto outf;
 484         ret = skb->len;
 485
 486  outf:
 487         kfree_skb(skb);
 488  out:
 489         return ret;
 490 }
 491
 492 static ssize_t ppp_write(struct file *file, const char __user *buf,
 493                          size_t count, loff_t *ppos)
 494 {
 495         struct ppp_file *pf = file->private_data;
 496         struct sk_buff *skb;
 497         ssize_t ret;
 498
 499         if (!pf)
 500                 return -ENXIO;
 501         /* All PPP packets should start with the 2-byte protocol */
 502         if (count < PPP_PROTO_LEN)
 503                 return -EINVAL;
 504         ret = -ENOMEM;
 505         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 506         if (!skb)
 507                 goto out;
 508         skb_reserve(skb, pf->hdrlen);
 509         ret = -EFAULT;
 510         if (copy_from_user(skb_put(skb, count), buf, count)) {
 511                 kfree_skb(skb);
 512                 goto out;
 513         }
 514
 515         switch (pf->kind) {
 516         case INTERFACE:
 517                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 518                 break;
 519         case CHANNEL:
 520                 skb_queue_tail(&pf->xq, skb);
 521                 ppp_channel_push(PF_TO_CHANNEL(pf));
 522                 break;
 523         }
 524
 525         ret = count;
 526
 527  out:
 528         return ret;
 529 }
 530
 531 /* No kernel lock - fine */
 532 static __poll_t ppp_poll(struct file *file, poll_table *wait)
 533 {
 534         struct ppp_file *pf = file->private_data;
 535         __poll_t mask;
 536
 537         if (!pf)
 538                 return 0;
 539         poll_wait(file, &pf->rwait, wait);
 540         mask = EPOLLOUT | EPOLLWRNORM;
 541         if (skb_peek(&pf->rq))
 542                 mask |= EPOLLIN | EPOLLRDNORM;
 543         if (pf->dead)
 544                 mask |= EPOLLHUP;
 545         else if (pf->kind == INTERFACE) {
 546                 /* see comment in ppp_read */
 547                 struct ppp *ppp = PF_TO_PPP(pf);
 548
 549                 ppp_recv_lock(ppp);
 550                 if (ppp->n_channels == 0 &&
 551                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 552                         mask |= EPOLLIN | EPOLLRDNORM;
 553                 ppp_recv_unlock(ppp);
 554         }
 555
 556         return mask;
 557 }
 558
 559 #ifdef CONFIG_PPP_FILTER
 560 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
 561 {
 562         struct sock_fprog_kern fprog;
 563         struct bpf_prog *res = NULL;
 564         int err;
 565
 566         if (!uprog->len)
 567                 return NULL;
 568
 569         /* uprog->len is unsigned short, so no overflow here */
 570         fprog.len = uprog->len;
 571         fprog.filter = memdup_user(uprog->filter,
 572                                    uprog->len * sizeof(struct sock_filter));
 573         if (IS_ERR(fprog.filter))
 574                 return ERR_CAST(fprog.filter);
 575
 576         err = bpf_prog_create(&res, &fprog);
 577         kfree(fprog.filter);
 578
 579         return err ? ERR_PTR(err) : res;
 580 }
 581
 582 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
 583 {
 584         struct sock_fprog uprog;
 585
 586         if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
 587                 return ERR_PTR(-EFAULT);
 588         return get_filter(&uprog);
 589 }
 590
 591 #ifdef CONFIG_COMPAT
 592 struct sock_fprog32 {
 593         unsigned short len;
 594         compat_caddr_t filter;
 595 };
 596
 597 #define PPPIOCSPASS32           _IOW('t', 71, struct sock_fprog32)
 598 #define PPPIOCSACTIVE32         _IOW('t', 70, struct sock_fprog32)
 599
 600 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
 601 {
 602         struct sock_fprog32 uprog32;
 603         struct sock_fprog uprog;
 604
 605         if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
 606                 return ERR_PTR(-EFAULT);
 607         uprog.len = uprog32.len;
 608         uprog.filter = compat_ptr(uprog32.filter);
 609         return get_filter(&uprog);
 610 }
 611 #endif
 612 #endif
 613
 614 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 615 {
 616         struct ppp_file *pf;
 617         struct ppp *ppp;
 618         int err = -EFAULT, val, val2, i;
 619         struct ppp_idle32 idle32;
 620         struct ppp_idle64 idle64;
 621         struct npioctl npi;
 622         int unit, cflags;
 623         struct slcompress *vj;
 624         void __user *argp = (void __user *)arg;
 625         int __user *p = argp;
 626
 627         mutex_lock(&ppp_mutex);
 628
 629         pf = file->private_data;
 630         if (!pf) {
 631                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 632                                            pf, file, cmd, arg);
 633                 goto out;
 634         }
 635
 636         if (cmd == PPPIOCDETACH) {
 637                 /*
 638                  * PPPIOCDETACH is no longer supported as it was heavily broken,
 639                  * and is only known to have been used by pppd older than
 640                  * ppp-2.4.2 (released November 2003).
 641                  */
 642                 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
 643                              current->comm, current->pid);
 644                 err = -EINVAL;
 645                 goto out;
 646         }
 647
 648         if (pf->kind == CHANNEL) {
 649                 struct channel *pch;
 650                 struct ppp_channel *chan;
 651
 652                 pch = PF_TO_CHANNEL(pf);
 653
 654                 switch (cmd) {
 655                 case PPPIOCCONNECT:
 656                         if (get_user(unit, p))
 657                                 break;
 658                         err = ppp_connect_channel(pch, unit);
 659                         break;
 660
 661                 case PPPIOCDISCONN:
 662                         err = ppp_disconnect_channel(pch);
 663                         break;
 664
 665                 default:
 666                         down_read(&pch->chan_sem);
 667                         chan = pch->chan;
 668                         err = -ENOTTY;
 669                         if (chan && chan->ops->ioctl)
 670                                 err = chan->ops->ioctl(chan, cmd, arg);
 671                         up_read(&pch->chan_sem);
 672                 }
 673                 goto out;
 674         }
 675
 676         if (pf->kind != INTERFACE) {
 677                 /* can't happen */
 678                 pr_err("PPP: not interface or channel??\n");
 679                 err = -EINVAL;
 680                 goto out;
 681         }
 682
 683         ppp = PF_TO_PPP(pf);
 684         switch (cmd) {
 685         case PPPIOCSMRU:
 686                 if (get_user(val, p))
 687                         break;
 688                 ppp->mru = val;
 689                 err = 0;
 690                 break;
 691
 692         case PPPIOCSFLAGS:
 693                 if (get_user(val, p))
 694                         break;
 695                 ppp_lock(ppp);
 696                 cflags = ppp->flags & ~val;
 697 #ifdef CONFIG_PPP_MULTILINK
 698                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 699                         ppp->nextseq = 0;
 700 #endif
 701                 ppp->flags = val & SC_FLAG_BITS;
 702                 ppp_unlock(ppp);
 703                 if (cflags & SC_CCP_OPEN)
 704                         ppp_ccp_closed(ppp);
 705                 err = 0;
 706                 break;
 707
 708         case PPPIOCGFLAGS:
 709                 val = ppp->flags | ppp->xstate | ppp->rstate;
 710                 if (put_user(val, p))
 711                         break;
 712                 err = 0;
 713                 break;
 714
 715         case PPPIOCSCOMPRESS:
 716         {
 717                 struct ppp_option_data data;
 718                 if (copy_from_user(&data, argp, sizeof(data)))
 719                         err = -EFAULT;
 720                 else
 721                         err = ppp_set_compress(ppp, &data);
 722                 break;
 723         }
 724         case PPPIOCGUNIT:
 725                 if (put_user(ppp->file.index, p))
 726                         break;
 727                 err = 0;
 728                 break;
 729
 730         case PPPIOCSDEBUG:
 731                 if (get_user(val, p))
 732                         break;
 733                 ppp->debug = val;
 734                 err = 0;
 735                 break;
 736
 737         case PPPIOCGDEBUG:
 738                 if (put_user(ppp->debug, p))
 739                         break;
 740                 err = 0;
 741                 break;
 742
 743         case PPPIOCGIDLE32:
 744                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 745                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
 746                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
 747                         break;
 748                 err = 0;
 749                 break;
 750
 751         case PPPIOCGIDLE64:
 752                 idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 753                 idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
 754                 if (copy_to_user(argp, &idle64, sizeof(idle64)))
 755                         break;
 756                 err = 0;
 757                 break;
 758
 759         case PPPIOCSMAXCID:
 760                 if (get_user(val, p))
 761                         break;
 762                 val2 = 15;
 763                 if ((val >> 16) != 0) {
 764                         val2 = val >> 16;
 765                         val &= 0xffff;
 766                 }
 767                 vj = slhc_init(val2+1, val+1);
 768                 if (IS_ERR(vj)) {
 769                         err = PTR_ERR(vj);
 770                         break;
 771                 }
 772                 ppp_lock(ppp);
 773                 if (ppp->vj)
 774                         slhc_free(ppp->vj);
 775                 ppp->vj = vj;
 776                 ppp_unlock(ppp);
 777                 err = 0;
 778                 break;
 779
 780         case PPPIOCGNPMODE:
 781         case PPPIOCSNPMODE:
 782                 if (copy_from_user(&npi, argp, sizeof(npi)))
 783                         break;
 784                 err = proto_to_npindex(npi.protocol);
 785                 if (err < 0)
 786                         break;
 787                 i = err;
 788                 if (cmd == PPPIOCGNPMODE) {
 789                         err = -EFAULT;
 790                         npi.mode = ppp->npmode[i];
 791                         if (copy_to_user(argp, &npi, sizeof(npi)))
 792                                 break;
 793                 } else {
 794                         ppp->npmode[i] = npi.mode;
 795                         /* we may be able to transmit more packets now (??) */
 796                         netif_wake_queue(ppp->dev);
 797                 }
 798                 err = 0;
 799                 break;
 800
 801 #ifdef CONFIG_PPP_FILTER
 802         case PPPIOCSPASS:
 803         case PPPIOCSACTIVE:
 804         {
 805                 struct bpf_prog *filter = ppp_get_filter(argp);
 806                 struct bpf_prog **which;
 807
 808                 if (IS_ERR(filter)) {
 809                         err = PTR_ERR(filter);
 810                         break;
 811                 }
 812                 if (cmd == PPPIOCSPASS)
 813                         which = &ppp->pass_filter;
 814                 else
 815                         which = &ppp->active_filter;
 816                 ppp_lock(ppp);
 817                 if (*which)
 818                         bpf_prog_destroy(*which);
 819                 *which = filter;
 820                 ppp_unlock(ppp);
 821                 err = 0;
 822                 break;
 823         }
 824 #endif /* CONFIG_PPP_FILTER */
 825
 826 #ifdef CONFIG_PPP_MULTILINK
 827         case PPPIOCSMRRU:
 828                 if (get_user(val, p))
 829                         break;
 830                 ppp_recv_lock(ppp);
 831                 ppp->mrru = val;
 832                 ppp_recv_unlock(ppp);
 833                 err = 0;
 834                 break;
 835 #endif /* CONFIG_PPP_MULTILINK */
 836
 837         default:
 838                 err = -ENOTTY;
 839         }
 840
 841 out:
 842         mutex_unlock(&ppp_mutex);
 843
 844         return err;
 845 }
 846
 847 #ifdef CONFIG_COMPAT
 848 struct ppp_option_data32 {
 849         compat_uptr_t           ptr;
 850         u32                     length;
 851         compat_int_t            transmit;
 852 };
 853 #define PPPIOCSCOMPRESS32       _IOW('t', 77, struct ppp_option_data32)
 854
 855 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 856 {
 857         struct ppp_file *pf;
 858         int err = -ENOIOCTLCMD;
 859         void __user *argp = (void __user *)arg;
 860
 861         mutex_lock(&ppp_mutex);
 862
 863         pf = file->private_data;
 864         if (pf && pf->kind == INTERFACE) {
 865                 struct ppp *ppp = PF_TO_PPP(pf);
 866                 switch (cmd) {
 867 #ifdef CONFIG_PPP_FILTER
 868                 case PPPIOCSPASS32:
 869                 case PPPIOCSACTIVE32:
 870                 {
 871                         struct bpf_prog *filter = compat_ppp_get_filter(argp);
 872                         struct bpf_prog **which;
 873
 874                         if (IS_ERR(filter)) {
 875                                 err = PTR_ERR(filter);
 876                                 break;
 877                         }
 878                         if (cmd == PPPIOCSPASS32)
 879                                 which = &ppp->pass_filter;
 880                         else
 881                                 which = &ppp->active_filter;
 882                         ppp_lock(ppp);
 883                         if (*which)
 884                                 bpf_prog_destroy(*which);
 885                         *which = filter;
 886                         ppp_unlock(ppp);
 887                         err = 0;
 888                         break;
 889                 }
 890 #endif /* CONFIG_PPP_FILTER */
 891                 case PPPIOCSCOMPRESS32:
 892                 {
 893                         struct ppp_option_data32 data32;
 894                         if (copy_from_user(&data32, argp, sizeof(data32))) {
 895                                 err = -EFAULT;
 896                         } else {
 897                                 struct ppp_option_data data = {
 898                                         .ptr = compat_ptr(data32.ptr),
 899                                         .length = data32.length,
 900                                         .transmit = data32.transmit
 901                                 };
 902                                 err = ppp_set_compress(ppp, &data);
 903                         }
 904                         break;
 905                 }
 906                 }
 907         }
 908         mutex_unlock(&ppp_mutex);
 909
 910         /* all other commands have compatible arguments */
 911         if (err == -ENOIOCTLCMD)
 912                 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 913
 914         return err;
 915 }
 916 #endif
 917
 918 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 919                         struct file *file, unsigned int cmd, unsigned long arg)
 920 {
 921         int unit, err = -EFAULT;
 922         struct ppp *ppp;
 923         struct channel *chan;
 924         struct ppp_net *pn;
 925         int __user *p = (int __user *)arg;
 926
 927         switch (cmd) {
 928         case PPPIOCNEWUNIT:
 929                 /* Create a new ppp unit */
 930                 if (get_user(unit, p))
 931                         break;
 932                 err = ppp_create_interface(net, file, &unit);
 933                 if (err < 0)
 934                         break;
 935
 936                 err = -EFAULT;
 937                 if (put_user(unit, p))
 938                         break;
 939                 err = 0;
 940                 break;
 941
 942         case PPPIOCATTACH:
 943                 /* Attach to an existing ppp unit */
 944                 if (get_user(unit, p))
 945                         break;
 946                 err = -ENXIO;
 947                 pn = ppp_pernet(net);
 948                 mutex_lock(&pn->all_ppp_mutex);
 949                 ppp = ppp_find_unit(pn, unit);
 950                 if (ppp) {
 951                         refcount_inc(&ppp->file.refcnt);
 952                         file->private_data = &ppp->file;
 953                         err = 0;
 954                 }
 955                 mutex_unlock(&pn->all_ppp_mutex);
 956                 break;
 957
 958         case PPPIOCATTCHAN:
 959                 if (get_user(unit, p))
 960                         break;
 961                 err = -ENXIO;
 962                 pn = ppp_pernet(net);
 963                 spin_lock_bh(&pn->all_channels_lock);
 964                 chan = ppp_find_channel(pn, unit);
 965                 if (chan) {
 966                         refcount_inc(&chan->file.refcnt);
 967                         file->private_data = &chan->file;
 968                         err = 0;
 969                 }
 970                 spin_unlock_bh(&pn->all_channels_lock);
 971                 break;
 972
 973         default:
 974                 err = -ENOTTY;
 975         }
 976
 977         return err;
 978 }
 979
 980 static const struct file_operations ppp_device_fops = {
 981         .owner          = THIS_MODULE,
 982         .read           = ppp_read,
 983         .write          = ppp_write,
 984         .poll           = ppp_poll,
 985         .unlocked_ioctl = ppp_ioctl,
 986 #ifdef CONFIG_COMPAT
 987         .compat_ioctl   = ppp_compat_ioctl,
 988 #endif
 989         .open           = ppp_open,
 990         .release        = ppp_release,
 991         .llseek         = noop_llseek,
 992 };
 993
 994 static __net_init int ppp_init_net(struct net *net)
 995 {
 996         struct ppp_net *pn = net_generic(net, ppp_net_id);
 997
 998         idr_init(&pn->units_idr);
 999         mutex_init(&pn->all_ppp_mutex);
1000
1001         INIT_LIST_HEAD(&pn->all_channels);
1002         INIT_LIST_HEAD(&pn->new_channels);
1003
1004         spin_lock_init(&pn->all_channels_lock);
1005
1006         return 0;
1007 }
1008
1009 static __net_exit void ppp_exit_net(struct net *net)
1010 {
1011         struct ppp_net *pn = net_generic(net, ppp_net_id);
1012         struct net_device *dev;
1013         struct net_device *aux;
1014         struct ppp *ppp;
1015         LIST_HEAD(list);
1016         int id;
1017
1018         rtnl_lock();
1019         for_each_netdev_safe(net, dev, aux) {
1020                 if (dev->netdev_ops == &ppp_netdev_ops)
1021                         unregister_netdevice_queue(dev, &list);
1022         }
1023
1024         idr_for_each_entry(&pn->units_idr, ppp, id)
1025                 /* Skip devices already unregistered by previous loop */
1026                 if (!net_eq(dev_net(ppp->dev), net))
1027                         unregister_netdevice_queue(ppp->dev, &list);
1028
1029         unregister_netdevice_many(&list);
1030         rtnl_unlock();
1031
1032         mutex_destroy(&pn->all_ppp_mutex);
1033         idr_destroy(&pn->units_idr);
1034         WARN_ON_ONCE(!list_empty(&pn->all_channels));
1035         WARN_ON_ONCE(!list_empty(&pn->new_channels));
1036 }
1037
1038 static struct pernet_operations ppp_net_ops = {
1039         .init = ppp_init_net,
1040         .exit = ppp_exit_net,
1041         .id   = &ppp_net_id,
1042         .size = sizeof(struct ppp_net),
1043 };
1044
1045 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1046 {
1047         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1048         int ret;
1049
1050         mutex_lock(&pn->all_ppp_mutex);
1051
1052         if (unit < 0) {
1053                 ret = unit_get(&pn->units_idr, ppp, 0);
1054                 if (ret < 0)
1055                         goto err;
1056                 if (!ifname_is_set) {
1057                         while (1) {
1058                                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1059                                 if (!__dev_get_by_name(ppp->ppp_net, ppp->dev->name))
1060                                         break;
1061                                 unit_put(&pn->units_idr, ret);
1062                                 ret = unit_get(&pn->units_idr, ppp, ret + 1);
1063                                 if (ret < 0)
1064                                         goto err;
1065                         }
1066                 }
1067         } else {
1068                 /* Caller asked for a specific unit number. Fail with -EEXIST
1069                  * if unavailable. For backward compatibility, return -EEXIST
1070                  * too if idr allocation fails; this makes pppd retry without
1071                  * requesting a specific unit number.
1072                  */
1073                 if (unit_find(&pn->units_idr, unit)) {
1074                         ret = -EEXIST;
1075                         goto err;
1076                 }
1077                 ret = unit_set(&pn->units_idr, ppp, unit);
1078                 if (ret < 0) {
1079                         /* Rewrite error for backward compatibility */
1080                         ret = -EEXIST;
1081                         goto err;
1082                 }
1083         }
1084         ppp->file.index = ret;
1085
1086         if (!ifname_is_set)
1087                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1088
1089         mutex_unlock(&pn->all_ppp_mutex);
1090
1091         ret = register_netdevice(ppp->dev);
1092         if (ret < 0)
1093                 goto err_unit;
1094
1095         atomic_inc(&ppp_unit_count);
1096
1097         return 0;
1098
1099 err_unit:
1100         mutex_lock(&pn->all_ppp_mutex);
1101         unit_put(&pn->units_idr, ppp->file.index);
1102 err:
1103         mutex_unlock(&pn->all_ppp_mutex);
1104
1105         return ret;
1106 }
1107
1108 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1109                              const struct ppp_config *conf)
1110 {
1111         struct ppp *ppp = netdev_priv(dev);
1112         int indx;
1113         int err;
1114         int cpu;
1115
1116         ppp->dev = dev;
1117         ppp->ppp_net = src_net;
1118         ppp->mru = PPP_MRU;
1119         ppp->owner = conf->file;
1120
1121         init_ppp_file(&ppp->file, INTERFACE);
1122         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1123
1124         for (indx = 0; indx < NUM_NP; ++indx)
1125                 ppp->npmode[indx] = NPMODE_PASS;
1126         INIT_LIST_HEAD(&ppp->channels);
1127         spin_lock_init(&ppp->rlock);
1128         spin_lock_init(&ppp->wlock);
1129
1130         ppp->xmit_recursion = alloc_percpu(int);
1131         if (!ppp->xmit_recursion) {
1132                 err = -ENOMEM;
1133                 goto err1;
1134         }
1135         for_each_possible_cpu(cpu)
1136                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1137
1138 #ifdef CONFIG_PPP_MULTILINK
1139         ppp->minseq = -1;
1140         skb_queue_head_init(&ppp->mrq);
1141 #endif /* CONFIG_PPP_MULTILINK */
1142 #ifdef CONFIG_PPP_FILTER
1143         ppp->pass_filter = NULL;
1144         ppp->active_filter = NULL;
1145 #endif /* CONFIG_PPP_FILTER */
1146
1147         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1148         if (err < 0)
1149                 goto err2;
1150
1151         conf->file->private_data = &ppp->file;
1152
1153         return 0;
1154 err2:
1155         free_percpu(ppp->xmit_recursion);
1156 err1:
1157         return err;
1158 }
1159
1160 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1161         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1162 };
1163
1164 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1165                            struct netlink_ext_ack *extack)
1166 {
1167         if (!data)
1168                 return -EINVAL;
1169
1170         if (!data[IFLA_PPP_DEV_FD])
1171                 return -EINVAL;
1172         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1173                 return -EBADF;
1174
1175         return 0;
1176 }
1177
1178 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1179                           struct nlattr *tb[], struct nlattr *data[],
1180                           struct netlink_ext_ack *extack)
1181 {
1182         struct ppp_config conf = {
1183                 .unit = -1,
1184                 .ifname_is_set = true,
1185         };
1186         struct file *file;
1187         int err;
1188
1189         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1190         if (!file)
1191                 return -EBADF;
1192
1193         /* rtnl_lock is already held here, but ppp_create_interface() locks
1194          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1195          * possible deadlock due to lock order inversion, at the cost of
1196          * pushing the problem back to userspace.
1197          */
1198         if (!mutex_trylock(&ppp_mutex)) {
1199                 err = -EBUSY;
1200                 goto out;
1201         }
1202
1203         if (file->f_op != &ppp_device_fops || file->private_data) {
1204                 err = -EBADF;
1205                 goto out_unlock;
1206         }
1207
1208         conf.file = file;
1209
1210         /* Don't use device name generated by the rtnetlink layer when ifname
1211          * isn't specified. Let ppp_dev_configure() set the device name using
1212          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1213          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1214          */
1215         if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1216                 conf.ifname_is_set = false;
1217
1218         err = ppp_dev_configure(src_net, dev, &conf);
1219
1220 out_unlock:
1221         mutex_unlock(&ppp_mutex);
1222 out:
1223         fput(file);
1224
1225         return err;
1226 }
1227
1228 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1229 {
1230         unregister_netdevice_queue(dev, head);
1231 }
1232
1233 static size_t ppp_nl_get_size(const struct net_device *dev)
1234 {
1235         return 0;
1236 }
1237
1238 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1239 {
1240         return 0;
1241 }
1242
1243 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1244 {
1245         struct ppp *ppp = netdev_priv(dev);
1246
1247         return ppp->ppp_net;
1248 }
1249
1250 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1251         .kind           = "ppp",
1252         .maxtype        = IFLA_PPP_MAX,
1253         .policy         = ppp_nl_policy,
1254         .priv_size      = sizeof(struct ppp),
1255         .setup          = ppp_setup,
1256         .validate       = ppp_nl_validate,
1257         .newlink        = ppp_nl_newlink,
1258         .dellink        = ppp_nl_dellink,
1259         .get_size       = ppp_nl_get_size,
1260         .fill_info      = ppp_nl_fill_info,
1261         .get_link_net   = ppp_nl_get_link_net,
1262 };
1263
1264 #define PPP_MAJOR       108
1265
1266 /* Called at boot time if ppp is compiled into the kernel,
1267    or at module load time (from init_module) if compiled as a module. */
1268 static int __init ppp_init(void)
1269 {
1270         int err;
1271
1272         pr_info("PPP generic driver version " PPP_VERSION "\n");
1273
1274         err = register_pernet_device(&ppp_net_ops);
1275         if (err) {
1276                 pr_err("failed to register PPP pernet device (%d)\n", err);
1277                 goto out;
1278         }
1279
1280         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1281         if (err) {
1282                 pr_err("failed to register PPP device (%d)\n", err);
1283                 goto out_net;
1284         }
1285
1286         ppp_class = class_create(THIS_MODULE, "ppp");
1287         if (IS_ERR(ppp_class)) {
1288                 err = PTR_ERR(ppp_class);
1289                 goto out_chrdev;
1290         }
1291
1292         err = rtnl_link_register(&ppp_link_ops);
1293         if (err) {
1294                 pr_err("failed to register rtnetlink PPP handler\n");
1295                 goto out_class;
1296         }
1297
1298         /* not a big deal if we fail here :-) */
1299         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1300
1301         return 0;
1302
1303 out_class:
1304         class_destroy(ppp_class);
1305 out_chrdev:
1306         unregister_chrdev(PPP_MAJOR, "ppp");
1307 out_net:
1308         unregister_pernet_device(&ppp_net_ops);
1309 out:
1310         return err;
1311 }
1312
1313 /*
1314  * Network interface unit routines.
1315  */
1316 static netdev_tx_t
1317 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1318 {
1319         struct ppp *ppp = netdev_priv(dev);
1320         int npi, proto;
1321         unsigned char *pp;
1322
1323         npi = ethertype_to_npindex(ntohs(skb->protocol));
1324         if (npi < 0)
1325                 goto outf;
1326
1327         /* Drop, accept or reject the packet */
1328         switch (ppp->npmode[npi]) {
1329         case NPMODE_PASS:
1330                 break;
1331         case NPMODE_QUEUE:
1332                 /* it would be nice to have a way to tell the network
1333                    system to queue this one up for later. */
1334                 goto outf;
1335         case NPMODE_DROP:
1336         case NPMODE_ERROR:
1337                 goto outf;
1338         }
1339
1340         /* Put the 2-byte PPP protocol number on the front,
1341            making sure there is room for the address and control fields. */
1342         if (skb_cow_head(skb, PPP_HDRLEN))
1343                 goto outf;
1344
1345         pp = skb_push(skb, 2);
1346         proto = npindex_to_proto[npi];
1347         put_unaligned_be16(proto, pp);
1348
1349         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1350         ppp_xmit_process(ppp, skb);
1351
1352         return NETDEV_TX_OK;
1353
1354  outf:
1355         kfree_skb(skb);
1356         ++dev->stats.tx_dropped;
1357         return NETDEV_TX_OK;
1358 }
1359
1360 static int
1361 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1362 {
1363         struct ppp *ppp = netdev_priv(dev);
1364         int err = -EFAULT;
1365         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1366         struct ppp_stats stats;
1367         struct ppp_comp_stats cstats;
1368         char *vers;
1369
1370         switch (cmd) {
1371         case SIOCGPPPSTATS:
1372                 ppp_get_stats(ppp, &stats);
1373                 if (copy_to_user(addr, &stats, sizeof(stats)))
1374                         break;
1375                 err = 0;
1376                 break;
1377
1378         case SIOCGPPPCSTATS:
1379                 memset(&cstats, 0, sizeof(cstats));
1380                 if (ppp->xc_state)
1381                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1382                 if (ppp->rc_state)
1383                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1384                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1385                         break;
1386                 err = 0;
1387                 break;
1388
1389         case SIOCGPPPVER:
1390                 vers = PPP_VERSION;
1391                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1392                         break;
1393                 err = 0;
1394                 break;
1395
1396         default:
1397                 err = -EINVAL;
1398         }
1399
1400         return err;
1401 }
1402
1403 static void
1404 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1405 {
1406         struct ppp *ppp = netdev_priv(dev);
1407
1408         ppp_recv_lock(ppp);
1409         stats64->rx_packets = ppp->stats64.rx_packets;
1410         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1411         ppp_recv_unlock(ppp);
1412
1413         ppp_xmit_lock(ppp);
1414         stats64->tx_packets = ppp->stats64.tx_packets;
1415         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1416         ppp_xmit_unlock(ppp);
1417
1418         stats64->rx_errors        = dev->stats.rx_errors;
1419         stats64->tx_errors        = dev->stats.tx_errors;
1420         stats64->rx_dropped       = dev->stats.rx_dropped;
1421         stats64->tx_dropped       = dev->stats.tx_dropped;
1422         stats64->rx_length_errors = dev->stats.rx_length_errors;
1423 }
1424
1425 static int ppp_dev_init(struct net_device *dev)
1426 {
1427         struct ppp *ppp;
1428
1429         netdev_lockdep_set_classes(dev);
1430
1431         ppp = netdev_priv(dev);
1432         /* Let the netdevice take a reference on the ppp file. This ensures
1433          * that ppp_destroy_interface() won't run before the device gets
1434          * unregistered.
1435          */
1436         refcount_inc(&ppp->file.refcnt);
1437
1438         return 0;
1439 }
1440
1441 static void ppp_dev_uninit(struct net_device *dev)
1442 {
1443         struct ppp *ppp = netdev_priv(dev);
1444         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1445
1446         ppp_lock(ppp);
1447         ppp->closing = 1;
1448         ppp_unlock(ppp);
1449
1450         mutex_lock(&pn->all_ppp_mutex);
1451         unit_put(&pn->units_idr, ppp->file.index);
1452         mutex_unlock(&pn->all_ppp_mutex);
1453
1454         ppp->owner = NULL;
1455
1456         ppp->file.dead = 1;
1457         wake_up_interruptible(&ppp->file.rwait);
1458 }
1459
1460 static void ppp_dev_priv_destructor(struct net_device *dev)
1461 {
1462         struct ppp *ppp;
1463
1464         ppp = netdev_priv(dev);
1465         if (refcount_dec_and_test(&ppp->file.refcnt))
1466                 ppp_destroy_interface(ppp);
1467 }
1468
1469 static const struct net_device_ops ppp_netdev_ops = {
1470         .ndo_init        = ppp_dev_init,
1471         .ndo_uninit      = ppp_dev_uninit,
1472         .ndo_start_xmit  = ppp_start_xmit,
1473         .ndo_do_ioctl    = ppp_net_ioctl,
1474         .ndo_get_stats64 = ppp_get_stats64,
1475 };
1476
1477 static struct device_type ppp_type = {
1478         .name = "ppp",
1479 };
1480
1481 static void ppp_setup(struct net_device *dev)
1482 {
1483         dev->netdev_ops = &ppp_netdev_ops;
1484         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1485
1486         dev->features |= NETIF_F_LLTX;
1487
1488         dev->hard_header_len = PPP_HDRLEN;
1489         dev->mtu = PPP_MRU;
1490         dev->addr_len = 0;
1491         dev->tx_queue_len = 3;
1492         dev->type = ARPHRD_PPP;
1493         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1494         dev->priv_destructor = ppp_dev_priv_destructor;
1495         netif_keep_dst(dev);
1496 }
1497
1498 /*
1499  * Transmit-side routines.
1500  */
1501
1502 /* Called to do any work queued up on the transmit side that can now be done */
1503 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1504 {
1505         ppp_xmit_lock(ppp);
1506         if (!ppp->closing) {
1507                 ppp_push(ppp);
1508
1509                 if (skb)
1510                         skb_queue_tail(&ppp->file.xq, skb);
1511                 while (!ppp->xmit_pending &&
1512                        (skb = skb_dequeue(&ppp->file.xq)))
1513                         ppp_send_frame(ppp, skb);
1514                 /* If there's no work left to do, tell the core net
1515                    code that we can accept some more. */
1516                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1517                         netif_wake_queue(ppp->dev);
1518                 else
1519                         netif_stop_queue(ppp->dev);
1520         } else {
1521                 kfree_skb(skb);
1522         }
1523         ppp_xmit_unlock(ppp);
1524 }
1525
1526 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1527 {
1528         local_bh_disable();
1529
1530         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1531                 goto err;
1532
1533         (*this_cpu_ptr(ppp->xmit_recursion))++;
1534         __ppp_xmit_process(ppp, skb);
1535         (*this_cpu_ptr(ppp->xmit_recursion))--;
1536
1537         local_bh_enable();
1538
1539         return;
1540
1541 err:
1542         local_bh_enable();
1543
1544         kfree_skb(skb);
1545
1546         if (net_ratelimit())
1547                 netdev_err(ppp->dev, "recursion detected\n");
1548 }
1549
1550 static inline struct sk_buff *
1551 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1552 {
1553         struct sk_buff *new_skb;
1554         int len;
1555         int new_skb_size = ppp->dev->mtu +
1556                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1557         int compressor_skb_size = ppp->dev->mtu +
1558                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1559         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1560         if (!new_skb) {
1561                 if (net_ratelimit())
1562                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1563                 return NULL;
1564         }
1565         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1566                 skb_reserve(new_skb,
1567                             ppp->dev->hard_header_len - PPP_HDRLEN);
1568
1569         /* compressor still expects A/C bytes in hdr */
1570         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1571                                    new_skb->data, skb->len + 2,
1572                                    compressor_skb_size);
1573         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1574                 consume_skb(skb);
1575                 skb = new_skb;
1576                 skb_put(skb, len);
1577                 skb_pull(skb, 2);       /* pull off A/C bytes */
1578         } else if (len == 0) {
1579                 /* didn't compress, or CCP not up yet */
1580                 consume_skb(new_skb);
1581                 new_skb = skb;
1582         } else {
1583                 /*
1584                  * (len < 0)
1585                  * MPPE requires that we do not send unencrypted
1586                  * frames.  The compressor will return -1 if we
1587                  * should drop the frame.  We cannot simply test
1588                  * the compress_proto because MPPE and MPPC share
1589                  * the same number.
1590                  */
1591                 if (net_ratelimit())
1592                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1593                 kfree_skb(skb);
1594                 consume_skb(new_skb);
1595                 new_skb = NULL;
1596         }
1597         return new_skb;
1598 }
1599
1600 /*
1601  * Compress and send a frame.
1602  * The caller should have locked the xmit path,
1603  * and xmit_pending should be 0.
1604  */
1605 static void
1606 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1607 {
1608         int proto = PPP_PROTO(skb);
1609         struct sk_buff *new_skb;
1610         int len;
1611         unsigned char *cp;
1612
1613         skb->dev = ppp->dev;
1614
1615         if (proto < 0x8000) {
1616 #ifdef CONFIG_PPP_FILTER
1617                 /* check if we should pass this packet */
1618                 /* the filter instructions are constructed assuming
1619                    a four-byte PPP header on each packet */
1620                 *(u8 *)skb_push(skb, 2) = 1;
1621                 if (ppp->pass_filter &&
1622                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1623                         if (ppp->debug & 1)
1624                                 netdev_printk(KERN_DEBUG, ppp->dev,
1625                                               "PPP: outbound frame "
1626                                               "not passed\n");
1627                         kfree_skb(skb);
1628                         return;
1629                 }
1630                 /* if this packet passes the active filter, record the time */
1631                 if (!(ppp->active_filter &&
1632                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1633                         ppp->last_xmit = jiffies;
1634                 skb_pull(skb, 2);
1635 #else
1636                 /* for data packets, record the time */
1637                 ppp->last_xmit = jiffies;
1638 #endif /* CONFIG_PPP_FILTER */
1639         }
1640
1641         ++ppp->stats64.tx_packets;
1642         ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1643
1644         switch (proto) {
1645         case PPP_IP:
1646                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1647                         break;
1648                 /* try to do VJ TCP header compression */
1649                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1650                                     GFP_ATOMIC);
1651                 if (!new_skb) {
1652                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1653                         goto drop;
1654                 }
1655                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1656                 cp = skb->data + 2;
1657                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1658                                     new_skb->data + 2, &cp,
1659                                     !(ppp->flags & SC_NO_TCP_CCID));
1660                 if (cp == skb->data + 2) {
1661                         /* didn't compress */
1662                         consume_skb(new_skb);
1663                 } else {
1664                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1665                                 proto = PPP_VJC_COMP;
1666                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1667                         } else {
1668                                 proto = PPP_VJC_UNCOMP;
1669                                 cp[0] = skb->data[2];
1670                         }
1671                         consume_skb(skb);
1672                         skb = new_skb;
1673                         cp = skb_put(skb, len + 2);
1674                         cp[0] = 0;
1675                         cp[1] = proto;
1676                 }
1677                 break;
1678
1679         case PPP_CCP:
1680                 /* peek at outbound CCP frames */
1681                 ppp_ccp_peek(ppp, skb, 0);
1682                 break;
1683         }
1684
1685         /* try to do packet compression */
1686         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1687             proto != PPP_LCP && proto != PPP_CCP) {
1688                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1689                         if (net_ratelimit())
1690                                 netdev_err(ppp->dev,
1691                                            "ppp: compression required but "
1692                                            "down - pkt dropped.\n");
1693                         goto drop;
1694                 }
1695                 skb = pad_compress_skb(ppp, skb);
1696                 if (!skb)
1697                         goto drop;
1698         }
1699
1700         /*
1701          * If we are waiting for traffic (demand dialling),
1702          * queue it up for pppd to receive.
1703          */
1704         if (ppp->flags & SC_LOOP_TRAFFIC) {
1705                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1706                         goto drop;
1707                 skb_queue_tail(&ppp->file.rq, skb);
1708                 wake_up_interruptible(&ppp->file.rwait);
1709                 return;
1710         }
1711
1712         ppp->xmit_pending = skb;
1713         ppp_push(ppp);
1714         return;
1715
1716  drop:
1717         kfree_skb(skb);
1718         ++ppp->dev->stats.tx_errors;
1719 }
1720
1721 /*
1722  * Try to send the frame in xmit_pending.
1723  * The caller should have the xmit path locked.
1724  */
1725 static void
1726 ppp_push(struct ppp *ppp)
1727 {
1728         struct list_head *list;
1729         struct channel *pch;
1730         struct sk_buff *skb = ppp->xmit_pending;
1731
1732         if (!skb)
1733                 return;
1734
1735         list = &ppp->channels;
1736         if (list_empty(list)) {
1737                 /* nowhere to send the packet, just drop it */
1738                 ppp->xmit_pending = NULL;
1739                 kfree_skb(skb);
1740                 return;
1741         }
1742
1743         if ((ppp->flags & SC_MULTILINK) == 0) {
1744                 /* not doing multilink: send it down the first channel */
1745                 list = list->next;
1746                 pch = list_entry(list, struct channel, clist);
1747
1748                 spin_lock(&pch->downl);
1749                 if (pch->chan) {
1750                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1751                                 ppp->xmit_pending = NULL;
1752                 } else {
1753                         /* channel got unregistered */
1754                         kfree_skb(skb);
1755                         ppp->xmit_pending = NULL;
1756                 }
1757                 spin_unlock(&pch->downl);
1758                 return;
1759         }
1760
1761 #ifdef CONFIG_PPP_MULTILINK
1762         /* Multilink: fragment the packet over as many links
1763            as can take the packet at the moment. */
1764         if (!ppp_mp_explode(ppp, skb))
1765                 return;
1766 #endif /* CONFIG_PPP_MULTILINK */
1767
1768         ppp->xmit_pending = NULL;
1769         kfree_skb(skb);
1770 }
1771
1772 #ifdef CONFIG_PPP_MULTILINK
1773 static bool mp_protocol_compress __read_mostly = true;
1774 module_param(mp_protocol_compress, bool, 0644);
1775 MODULE_PARM_DESC(mp_protocol_compress,
1776                  "compress protocol id in multilink fragments");
1777
1778 /*
1779  * Divide a packet to be transmitted into fragments and
1780  * send them out the individual links.
1781  */
1782 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1783 {
1784         int len, totlen;
1785         int i, bits, hdrlen, mtu;
1786         int flen;
1787         int navail, nfree, nzero;
1788         int nbigger;
1789         int totspeed;
1790         int totfree;
1791         unsigned char *p, *q;
1792         struct list_head *list;
1793         struct channel *pch;
1794         struct sk_buff *frag;
1795         struct ppp_channel *chan;
1796
1797         totspeed = 0; /*total bitrate of the bundle*/
1798         nfree = 0; /* # channels which have no packet already queued */
1799         navail = 0; /* total # of usable channels (not deregistered) */
1800         nzero = 0; /* number of channels with zero speed associated*/
1801         totfree = 0; /*total # of channels available and
1802                                   *having no queued packets before
1803                                   *starting the fragmentation*/
1804
1805         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1806         i = 0;
1807         list_for_each_entry(pch, &ppp->channels, clist) {
1808                 if (pch->chan) {
1809                         pch->avail = 1;
1810                         navail++;
1811                         pch->speed = pch->chan->speed;
1812                 } else {
1813                         pch->avail = 0;
1814                 }
1815                 if (pch->avail) {
1816                         if (skb_queue_empty(&pch->file.xq) ||
1817                                 !pch->had_frag) {
1818                                         if (pch->speed == 0)
1819                                                 nzero++;
1820                                         else
1821                                                 totspeed += pch->speed;
1822
1823                                         pch->avail = 2;
1824                                         ++nfree;
1825                                         ++totfree;
1826                                 }
1827                         if (!pch->had_frag && i < ppp->nxchan)
1828                                 ppp->nxchan = i;
1829                 }
1830                 ++i;
1831         }
1832         /*
1833          * Don't start sending this packet unless at least half of
1834          * the channels are free.  This gives much better TCP
1835          * performance if we have a lot of channels.
1836          */
1837         if (nfree == 0 || nfree < navail / 2)
1838                 return 0; /* can't take now, leave it in xmit_pending */
1839
1840         /* Do protocol field compression */
1841         p = skb->data;
1842         len = skb->len;
1843         if (*p == 0 && mp_protocol_compress) {
1844                 ++p;
1845                 --len;
1846         }
1847
1848         totlen = len;
1849         nbigger = len % nfree;
1850
1851         /* skip to the channel after the one we last used
1852            and start at that one */
1853         list = &ppp->channels;
1854         for (i = 0; i < ppp->nxchan; ++i) {
1855                 list = list->next;
1856                 if (list == &ppp->channels) {
1857                         i = 0;
1858                         break;
1859                 }
1860         }
1861
1862         /* create a fragment for each channel */
1863         bits = B;
1864         while (len > 0) {
1865                 list = list->next;
1866                 if (list == &ppp->channels) {
1867                         i = 0;
1868                         continue;
1869                 }
1870                 pch = list_entry(list, struct channel, clist);
1871                 ++i;
1872                 if (!pch->avail)
1873                         continue;
1874
1875                 /*
1876                  * Skip this channel if it has a fragment pending already and
1877                  * we haven't given a fragment to all of the free channels.
1878                  */
1879                 if (pch->avail == 1) {
1880                         if (nfree > 0)
1881                                 continue;
1882                 } else {
1883                         pch->avail = 1;
1884                 }
1885
1886                 /* check the channel's mtu and whether it is still attached. */
1887                 spin_lock(&pch->downl);
1888                 if (pch->chan == NULL) {
1889                         /* can't use this channel, it's being deregistered */
1890                         if (pch->speed == 0)
1891                                 nzero--;
1892                         else
1893                                 totspeed -= pch->speed;
1894
1895                         spin_unlock(&pch->downl);
1896                         pch->avail = 0;
1897                         totlen = len;
1898                         totfree--;
1899                         nfree--;
1900                         if (--navail == 0)
1901                                 break;
1902                         continue;
1903                 }
1904
1905                 /*
1906                 *if the channel speed is not set divide
1907                 *the packet evenly among the free channels;
1908                 *otherwise divide it according to the speed
1909                 *of the channel we are going to transmit on
1910                 */
1911                 flen = len;
1912                 if (nfree > 0) {
1913                         if (pch->speed == 0) {
1914                                 flen = len/nfree;
1915                                 if (nbigger > 0) {
1916                                         flen++;
1917                                         nbigger--;
1918                                 }
1919                         } else {
1920                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1921                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1922                                 if (nbigger > 0) {
1923                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1924                                         nbigger -= ((totfree - nzero)*pch->speed)/
1925                                                         totspeed;
1926                                 }
1927                         }
1928                         nfree--;
1929                 }
1930
1931                 /*
1932                  *check if we are on the last channel or
1933                  *we exceded the length of the data to
1934                  *fragment
1935                  */
1936                 if ((nfree <= 0) || (flen > len))
1937                         flen = len;
1938                 /*
1939                  *it is not worth to tx on slow channels:
1940                  *in that case from the resulting flen according to the
1941                  *above formula will be equal or less than zero.
1942                  *Skip the channel in this case
1943                  */
1944                 if (flen <= 0) {
1945                         pch->avail = 2;
1946                         spin_unlock(&pch->downl);
1947                         continue;
1948                 }
1949
1950                 /*
1951                  * hdrlen includes the 2-byte PPP protocol field, but the
1952                  * MTU counts only the payload excluding the protocol field.
1953                  * (RFC1661 Section 2)
1954                  */
1955                 mtu = pch->chan->mtu - (hdrlen - 2);
1956                 if (mtu < 4)
1957                         mtu = 4;
1958                 if (flen > mtu)
1959                         flen = mtu;
1960                 if (flen == len)
1961                         bits |= E;
1962                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1963                 if (!frag)
1964                         goto noskb;
1965                 q = skb_put(frag, flen + hdrlen);
1966
1967                 /* make the MP header */
1968                 put_unaligned_be16(PPP_MP, q);
1969                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1970                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1971                         q[3] = ppp->nxseq;
1972                 } else {
1973                         q[2] = bits;
1974                         q[3] = ppp->nxseq >> 16;
1975                         q[4] = ppp->nxseq >> 8;
1976                         q[5] = ppp->nxseq;
1977                 }
1978
1979                 memcpy(q + hdrlen, p, flen);
1980
1981                 /* try to send it down the channel */
1982                 chan = pch->chan;
1983                 if (!skb_queue_empty(&pch->file.xq) ||
1984                         !chan->ops->start_xmit(chan, frag))
1985                         skb_queue_tail(&pch->file.xq, frag);
1986                 pch->had_frag = 1;
1987                 p += flen;
1988                 len -= flen;
1989                 ++ppp->nxseq;
1990                 bits = 0;
1991                 spin_unlock(&pch->downl);
1992         }
1993         ppp->nxchan = i;
1994
1995         return 1;
1996
1997  noskb:
1998         spin_unlock(&pch->downl);
1999         if (ppp->debug & 1)
2000                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2001         ++ppp->dev->stats.tx_errors;
2002         ++ppp->nxseq;
2003         return 1;       /* abandon the frame */
2004 }
2005 #endif /* CONFIG_PPP_MULTILINK */
2006
2007 /* Try to send data out on a channel */
2008 static void __ppp_channel_push(struct channel *pch)
2009 {
2010         struct sk_buff *skb;
2011         struct ppp *ppp;
2012
2013         spin_lock(&pch->downl);
2014         if (pch->chan) {
2015                 while (!skb_queue_empty(&pch->file.xq)) {
2016                         skb = skb_dequeue(&pch->file.xq);
2017                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2018                                 /* put the packet back and try again later */
2019                                 skb_queue_head(&pch->file.xq, skb);
2020                                 break;
2021                         }
2022                 }
2023         } else {
2024                 /* channel got deregistered */
2025                 skb_queue_purge(&pch->file.xq);
2026         }
2027         spin_unlock(&pch->downl);
2028         /* see if there is anything from the attached unit to be sent */
2029         if (skb_queue_empty(&pch->file.xq)) {
2030                 ppp = pch->ppp;
2031                 if (ppp)
2032                         __ppp_xmit_process(ppp, NULL);
2033         }
2034 }
2035
2036 static void ppp_channel_push(struct channel *pch)
2037 {
2038         read_lock_bh(&pch->upl);
2039         if (pch->ppp) {
2040                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2041                 __ppp_channel_push(pch);
2042                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2043         } else {
2044                 __ppp_channel_push(pch);
2045         }
2046         read_unlock_bh(&pch->upl);
2047 }
2048
2049 /*
2050  * Receive-side routines.
2051  */
2052
2053 struct ppp_mp_skb_parm {
2054         u32             sequence;
2055         u8              BEbits;
2056 };
2057 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
2058
2059 static inline void
2060 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2061 {
2062         ppp_recv_lock(ppp);
2063         if (!ppp->closing)
2064                 ppp_receive_frame(ppp, skb, pch);
2065         else
2066                 kfree_skb(skb);
2067         ppp_recv_unlock(ppp);
2068 }
2069
2070 /**
2071  * __ppp_decompress_proto - Decompress protocol field, slim version.
2072  * @skb: Socket buffer where protocol field should be decompressed. It must have
2073  *       at least 1 byte of head room and 1 byte of linear data. First byte of
2074  *       data must be a protocol field byte.
2075  *
2076  * Decompress protocol field in PPP header if it's compressed, e.g. when
2077  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2078  * length are done in this function.
2079  */
2080 static void __ppp_decompress_proto(struct sk_buff *skb)
2081 {
2082         if (skb->data[0] & 0x01)
2083                 *(u8 *)skb_push(skb, 1) = 0x00;
2084 }
2085
2086 /**
2087  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2088  * @skb: Socket buffer where protocol field should be decompressed. First byte
2089  *       of data must be a protocol field byte.
2090  *
2091  * Decompress protocol field in PPP header if it's compressed, e.g. when
2092  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2093  * sure that skb data room is sufficient for Protocol field, before and after
2094  * decompression.
2095  *
2096  * Return: true - decompressed successfully, false - not enough room in skb.
2097  */
2098 static bool ppp_decompress_proto(struct sk_buff *skb)
2099 {
2100         /* At least one byte should be present (if protocol is compressed) */
2101         if (!pskb_may_pull(skb, 1))
2102                 return false;
2103
2104         __ppp_decompress_proto(skb);
2105
2106         /* Protocol field should occupy 2 bytes when not compressed */
2107         return pskb_may_pull(skb, 2);
2108 }
2109
2110 void
2111 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2112 {
2113         struct channel *pch = chan->ppp;
2114         int proto;
2115
2116         if (!pch) {
2117                 kfree_skb(skb);
2118                 return;
2119         }
2120
2121         read_lock_bh(&pch->upl);
2122         if (!ppp_decompress_proto(skb)) {
2123                 kfree_skb(skb);
2124                 if (pch->ppp) {
2125                         ++pch->ppp->dev->stats.rx_length_errors;
2126                         ppp_receive_error(pch->ppp);
2127                 }
2128                 goto done;
2129         }
2130
2131         proto = PPP_PROTO(skb);
2132         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2133                 /* put it on the channel queue */
2134                 skb_queue_tail(&pch->file.rq, skb);
2135                 /* drop old frames if queue too long */
2136                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2137                        (skb = skb_dequeue(&pch->file.rq)))
2138                         kfree_skb(skb);
2139                 wake_up_interruptible(&pch->file.rwait);
2140         } else {
2141                 ppp_do_recv(pch->ppp, skb, pch);
2142         }
2143
2144 done:
2145         read_unlock_bh(&pch->upl);
2146 }
2147
2148 /* Put a 0-length skb in the receive queue as an error indication */
2149 void
2150 ppp_input_error(struct ppp_channel *chan, int code)
2151 {
2152         struct channel *pch = chan->ppp;
2153         struct sk_buff *skb;
2154
2155         if (!pch)
2156                 return;
2157
2158         read_lock_bh(&pch->upl);
2159         if (pch->ppp) {
2160                 skb = alloc_skb(0, GFP_ATOMIC);
2161                 if (skb) {
2162                         skb->len = 0;           /* probably unnecessary */
2163                         skb->cb[0] = code;
2164                         ppp_do_recv(pch->ppp, skb, pch);
2165                 }
2166         }
2167         read_unlock_bh(&pch->upl);
2168 }
2169
2170 /*
2171  * We come in here to process a received frame.
2172  * The receive side of the ppp unit is locked.
2173  */
2174 static void
2175 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2176 {
2177         /* note: a 0-length skb is used as an error indication */
2178         if (skb->len > 0) {
2179                 skb_checksum_complete_unset(skb);
2180 #ifdef CONFIG_PPP_MULTILINK
2181                 /* XXX do channel-level decompression here */
2182                 if (PPP_PROTO(skb) == PPP_MP)
2183                         ppp_receive_mp_frame(ppp, skb, pch);
2184                 else
2185 #endif /* CONFIG_PPP_MULTILINK */
2186                         ppp_receive_nonmp_frame(ppp, skb);
2187         } else {
2188                 kfree_skb(skb);
2189                 ppp_receive_error(ppp);
2190         }
2191 }
2192
2193 static void
2194 ppp_receive_error(struct ppp *ppp)
2195 {
2196         ++ppp->dev->stats.rx_errors;
2197         if (ppp->vj)
2198                 slhc_toss(ppp->vj);
2199 }
2200
2201 static void
2202 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2203 {
2204         struct sk_buff *ns;
2205         int proto, len, npi;
2206
2207         /*
2208          * Decompress the frame, if compressed.
2209          * Note that some decompressors need to see uncompressed frames
2210          * that come in as well as compressed frames.
2211          */
2212         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2213             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2214                 skb = ppp_decompress_frame(ppp, skb);
2215
2216         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2217                 goto err;
2218
2219         /* At this point the "Protocol" field MUST be decompressed, either in
2220          * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2221          */
2222         proto = PPP_PROTO(skb);
2223         switch (proto) {
2224         case PPP_VJC_COMP:
2225                 /* decompress VJ compressed packets */
2226                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2227                         goto err;
2228
2229                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2230                         /* copy to a new sk_buff with more tailroom */
2231                         ns = dev_alloc_skb(skb->len + 128);
2232                         if (!ns) {
2233                                 netdev_err(ppp->dev, "PPP: no memory "
2234                                            "(VJ decomp)\n");
2235                                 goto err;
2236                         }
2237                         skb_reserve(ns, 2);
2238                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2239                         consume_skb(skb);
2240                         skb = ns;
2241                 }
2242                 else
2243                         skb->ip_summed = CHECKSUM_NONE;
2244
2245                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2246                 if (len <= 0) {
2247                         netdev_printk(KERN_DEBUG, ppp->dev,
2248                                       "PPP: VJ decompression error\n");
2249                         goto err;
2250                 }
2251                 len += 2;
2252                 if (len > skb->len)
2253                         skb_put(skb, len - skb->len);
2254                 else if (len < skb->len)
2255                         skb_trim(skb, len);
2256                 proto = PPP_IP;
2257                 break;
2258
2259         case PPP_VJC_UNCOMP:
2260                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2261                         goto err;
2262
2263                 /* Until we fix the decompressor need to make sure
2264                  * data portion is linear.
2265                  */
2266                 if (!pskb_may_pull(skb, skb->len))
2267                         goto err;
2268
2269                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2270                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2271                         goto err;
2272                 }
2273                 proto = PPP_IP;
2274                 break;
2275
2276         case PPP_CCP:
2277                 ppp_ccp_peek(ppp, skb, 1);
2278                 break;
2279         }
2280
2281         ++ppp->stats64.rx_packets;
2282         ppp->stats64.rx_bytes += skb->len - 2;
2283
2284         npi = proto_to_npindex(proto);
2285         if (npi < 0) {
2286                 /* control or unknown frame - pass it to pppd */
2287                 skb_queue_tail(&ppp->file.rq, skb);
2288                 /* limit queue length by dropping old frames */
2289                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2290                        (skb = skb_dequeue(&ppp->file.rq)))
2291                         kfree_skb(skb);
2292                 /* wake up any process polling or blocking on read */
2293                 wake_up_interruptible(&ppp->file.rwait);
2294
2295         } else {
2296                 /* network protocol frame - give it to the kernel */
2297
2298 #ifdef CONFIG_PPP_FILTER
2299                 /* check if the packet passes the pass and active filters */
2300                 /* the filter instructions are constructed assuming
2301                    a four-byte PPP header on each packet */
2302                 if (ppp->pass_filter || ppp->active_filter) {
2303                         if (skb_unclone(skb, GFP_ATOMIC))
2304                                 goto err;
2305
2306                         *(u8 *)skb_push(skb, 2) = 0;
2307                         if (ppp->pass_filter &&
2308                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2309                                 if (ppp->debug & 1)
2310                                         netdev_printk(KERN_DEBUG, ppp->dev,
2311                                                       "PPP: inbound frame "
2312                                                       "not passed\n");
2313                                 kfree_skb(skb);
2314                                 return;
2315                         }
2316                         if (!(ppp->active_filter &&
2317                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2318                                 ppp->last_recv = jiffies;
2319                         __skb_pull(skb, 2);
2320                 } else
2321 #endif /* CONFIG_PPP_FILTER */
2322                         ppp->last_recv = jiffies;
2323
2324                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2325                     ppp->npmode[npi] != NPMODE_PASS) {
2326                         kfree_skb(skb);
2327                 } else {
2328                         /* chop off protocol */
2329                         skb_pull_rcsum(skb, 2);
2330                         skb->dev = ppp->dev;
2331                         skb->protocol = htons(npindex_to_ethertype[npi]);
2332                         skb_reset_mac_header(skb);
2333                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2334                                                       dev_net(ppp->dev)));
2335                         netif_rx(skb);
2336                 }
2337         }
2338         return;
2339
2340  err:
2341         kfree_skb(skb);
2342         ppp_receive_error(ppp);
2343 }
2344
2345 static struct sk_buff *
2346 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2347 {
2348         int proto = PPP_PROTO(skb);
2349         struct sk_buff *ns;
2350         int len;
2351
2352         /* Until we fix all the decompressor's need to make sure
2353          * data portion is linear.
2354          */
2355         if (!pskb_may_pull(skb, skb->len))
2356                 goto err;
2357
2358         if (proto == PPP_COMP) {
2359                 int obuff_size;
2360
2361                 switch(ppp->rcomp->compress_proto) {
2362                 case CI_MPPE:
2363                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2364                         break;
2365                 default:
2366                         obuff_size = ppp->mru + PPP_HDRLEN;
2367                         break;
2368                 }
2369
2370                 ns = dev_alloc_skb(obuff_size);
2371                 if (!ns) {
2372                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2373                                    "no memory\n");
2374                         goto err;
2375                 }
2376                 /* the decompressor still expects the A/C bytes in the hdr */
2377                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2378                                 skb->len + 2, ns->data, obuff_size);
2379                 if (len < 0) {
2380                         /* Pass the compressed frame to pppd as an
2381                            error indication. */
2382                         if (len == DECOMP_FATALERROR)
2383                                 ppp->rstate |= SC_DC_FERROR;
2384                         kfree_skb(ns);
2385                         goto err;
2386                 }
2387
2388                 consume_skb(skb);
2389                 skb = ns;
2390                 skb_put(skb, len);
2391                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2392
2393                 /* Don't call __ppp_decompress_proto() here, but instead rely on
2394                  * corresponding algo (mppe/bsd/deflate) to decompress it.
2395                  */
2396         } else {
2397                 /* Uncompressed frame - pass to decompressor so it
2398                    can update its dictionary if necessary. */
2399                 if (ppp->rcomp->incomp)
2400                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2401                                            skb->len + 2);
2402         }
2403
2404         return skb;
2405
2406  err:
2407         ppp->rstate |= SC_DC_ERROR;
2408         ppp_receive_error(ppp);
2409         return skb;
2410 }
2411
2412 #ifdef CONFIG_PPP_MULTILINK
2413 /*
2414  * Receive a multilink frame.
2415  * We put it on the reconstruction queue and then pull off
2416  * as many completed frames as we can.
2417  */
2418 static void
2419 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2420 {
2421         u32 mask, seq;
2422         struct channel *ch;
2423         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2424
2425         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2426                 goto err;               /* no good, throw it away */
2427
2428         /* Decode sequence number and begin/end bits */
2429         if (ppp->flags & SC_MP_SHORTSEQ) {
2430                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2431                 mask = 0xfff;
2432         } else {
2433                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2434                 mask = 0xffffff;
2435         }
2436         PPP_MP_CB(skb)->BEbits = skb->data[2];
2437         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2438
2439         /*
2440          * Do protocol ID decompression on the first fragment of each packet.
2441          * We have to do that here, because ppp_receive_nonmp_frame() expects
2442          * decompressed protocol field.
2443          */
2444         if (PPP_MP_CB(skb)->BEbits & B)
2445                 __ppp_decompress_proto(skb);
2446
2447         /*
2448          * Expand sequence number to 32 bits, making it as close
2449          * as possible to ppp->minseq.
2450          */
2451         seq |= ppp->minseq & ~mask;
2452         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2453                 seq += mask + 1;
2454         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2455                 seq -= mask + 1;        /* should never happen */
2456         PPP_MP_CB(skb)->sequence = seq;
2457         pch->lastseq = seq;
2458
2459         /*
2460          * If this packet comes before the next one we were expecting,
2461          * drop it.
2462          */
2463         if (seq_before(seq, ppp->nextseq)) {
2464                 kfree_skb(skb);
2465                 ++ppp->dev->stats.rx_dropped;
2466                 ppp_receive_error(ppp);
2467                 return;
2468         }
2469
2470         /*
2471          * Reevaluate minseq, the minimum over all channels of the
2472          * last sequence number received on each channel.  Because of
2473          * the increasing sequence number rule, we know that any fragment
2474          * before `minseq' which hasn't arrived is never going to arrive.
2475          * The list of channels can't change because we have the receive
2476          * side of the ppp unit locked.
2477          */
2478         list_for_each_entry(ch, &ppp->channels, clist) {
2479                 if (seq_before(ch->lastseq, seq))
2480                         seq = ch->lastseq;
2481         }
2482         if (seq_before(ppp->minseq, seq))
2483                 ppp->minseq = seq;
2484
2485         /* Put the fragment on the reconstruction queue */
2486         ppp_mp_insert(ppp, skb);
2487
2488         /* If the queue is getting long, don't wait any longer for packets
2489            before the start of the queue. */
2490         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2491                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2492                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2493                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2494         }
2495
2496         /* Pull completed packets off the queue and receive them. */
2497         while ((skb = ppp_mp_reconstruct(ppp))) {
2498                 if (pskb_may_pull(skb, 2))
2499                         ppp_receive_nonmp_frame(ppp, skb);
2500                 else {
2501                         ++ppp->dev->stats.rx_length_errors;
2502                         kfree_skb(skb);
2503                         ppp_receive_error(ppp);
2504                 }
2505         }
2506
2507         return;
2508
2509  err:
2510         kfree_skb(skb);
2511         ppp_receive_error(ppp);
2512 }
2513
2514 /*
2515  * Insert a fragment on the MP reconstruction queue.
2516  * The queue is ordered by increasing sequence number.
2517  */
2518 static void
2519 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2520 {
2521         struct sk_buff *p;
2522         struct sk_buff_head *list = &ppp->mrq;
2523         u32 seq = PPP_MP_CB(skb)->sequence;
2524
2525         /* N.B. we don't need to lock the list lock because we have the
2526            ppp unit receive-side lock. */
2527         skb_queue_walk(list, p) {
2528                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2529                         break;
2530         }
2531         __skb_queue_before(list, p, skb);
2532 }
2533
2534 /*
2535  * Reconstruct a packet from the MP fragment queue.
2536  * We go through increasing sequence numbers until we find a
2537  * complete packet, or we get to the sequence number for a fragment
2538  * which hasn't arrived but might still do so.
2539  */
2540 static struct sk_buff *
2541 ppp_mp_reconstruct(struct ppp *ppp)
2542 {
2543         u32 seq = ppp->nextseq;
2544         u32 minseq = ppp->minseq;
2545         struct sk_buff_head *list = &ppp->mrq;
2546         struct sk_buff *p, *tmp;
2547         struct sk_buff *head, *tail;
2548         struct sk_buff *skb = NULL;
2549         int lost = 0, len = 0;
2550
2551         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2552                 return NULL;
2553         head = __skb_peek(list);
2554         tail = NULL;
2555         skb_queue_walk_safe(list, p, tmp) {
2556         again:
2557                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2558                         /* this can't happen, anyway ignore the skb */
2559                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2560                                    "seq %u < %u\n",
2561                                    PPP_MP_CB(p)->sequence, seq);
2562                         __skb_unlink(p, list);
2563                         kfree_skb(p);
2564                         continue;
2565                 }
2566                 if (PPP_MP_CB(p)->sequence != seq) {
2567                         u32 oldseq;
2568                         /* Fragment `seq' is missing.  If it is after
2569                            minseq, it might arrive later, so stop here. */
2570                         if (seq_after(seq, minseq))
2571                                 break;
2572                         /* Fragment `seq' is lost, keep going. */
2573                         lost = 1;
2574                         oldseq = seq;
2575                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2576                                 minseq + 1: PPP_MP_CB(p)->sequence;
2577
2578                         if (ppp->debug & 1)
2579                                 netdev_printk(KERN_DEBUG, ppp->dev,
2580                                               "lost frag %u..%u\n",
2581                                               oldseq, seq-1);
2582
2583                         goto again;
2584                 }
2585
2586                 /*
2587                  * At this point we know that all the fragments from
2588                  * ppp->nextseq to seq are either present or lost.
2589                  * Also, there are no complete packets in the queue
2590                  * that have no missing fragments and end before this
2591                  * fragment.
2592                  */
2593
2594                 /* B bit set indicates this fragment starts a packet */
2595                 if (PPP_MP_CB(p)->BEbits & B) {
2596                         head = p;
2597                         lost = 0;
2598                         len = 0;
2599                 }
2600
2601                 len += p->len;
2602
2603                 /* Got a complete packet yet? */
2604                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2605                     (PPP_MP_CB(head)->BEbits & B)) {
2606                         if (len > ppp->mrru + 2) {
2607                                 ++ppp->dev->stats.rx_length_errors;
2608                                 netdev_printk(KERN_DEBUG, ppp->dev,
2609                                               "PPP: reconstructed packet"
2610                                               " is too long (%d)\n", len);
2611                         } else {
2612                                 tail = p;
2613                                 break;
2614                         }
2615                         ppp->nextseq = seq + 1;
2616                 }
2617
2618                 /*
2619                  * If this is the ending fragment of a packet,
2620                  * and we haven't found a complete valid packet yet,
2621                  * we can discard up to and including this fragment.
2622                  */
2623                 if (PPP_MP_CB(p)->BEbits & E) {
2624                         struct sk_buff *tmp2;
2625
2626                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2627                                 if (ppp->debug & 1)
2628                                         netdev_printk(KERN_DEBUG, ppp->dev,
2629                                                       "discarding frag %u\n",
2630                                                       PPP_MP_CB(p)->sequence);
2631                                 __skb_unlink(p, list);
2632                                 kfree_skb(p);
2633                         }
2634                         head = skb_peek(list);
2635                         if (!head)
2636                                 break;
2637                 }
2638                 ++seq;
2639         }
2640
2641         /* If we have a complete packet, copy it all into one skb. */
2642         if (tail != NULL) {
2643                 /* If we have discarded any fragments,
2644                    signal a receive error. */
2645                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2646                         skb_queue_walk_safe(list, p, tmp) {
2647                                 if (p == head)
2648                                         break;
2649                                 if (ppp->debug & 1)
2650                                         netdev_printk(KERN_DEBUG, ppp->dev,
2651                                                       "discarding frag %u\n",
2652                                                       PPP_MP_CB(p)->sequence);
2653                                 __skb_unlink(p, list);
2654                                 kfree_skb(p);
2655                         }
2656
2657                         if (ppp->debug & 1)
2658                                 netdev_printk(KERN_DEBUG, ppp->dev,
2659                                               "  missed pkts %u..%u\n",
2660                                               ppp->nextseq,
2661                                               PPP_MP_CB(head)->sequence-1);
2662                         ++ppp->dev->stats.rx_dropped;
2663                         ppp_receive_error(ppp);
2664                 }
2665
2666                 skb = head;
2667                 if (head != tail) {
2668                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2669                         p = skb_queue_next(list, head);
2670                         __skb_unlink(skb, list);
2671                         skb_queue_walk_from_safe(list, p, tmp) {
2672                                 __skb_unlink(p, list);
2673                                 *fragpp = p;
2674                                 p->next = NULL;
2675                                 fragpp = &p->next;
2676
2677                                 skb->len += p->len;
2678                                 skb->data_len += p->len;
2679                                 skb->truesize += p->truesize;
2680
2681                                 if (p == tail)
2682                                         break;
2683                         }
2684                 } else {
2685                         __skb_unlink(skb, list);
2686                 }
2687
2688                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2689         }
2690
2691         return skb;
2692 }
2693 #endif /* CONFIG_PPP_MULTILINK */
2694
2695 /*
2696  * Channel interface.
2697  */
2698
2699 /* Create a new, unattached ppp channel. */
2700 int ppp_register_channel(struct ppp_channel *chan)
2701 {
2702         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2703 }
2704
2705 /* Create a new, unattached ppp channel for specified net. */
2706 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2707 {
2708         struct channel *pch;
2709         struct ppp_net *pn;
2710
2711         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2712         if (!pch)
2713                 return -ENOMEM;
2714
2715         pn = ppp_pernet(net);
2716
2717         pch->ppp = NULL;
2718         pch->chan = chan;
2719         pch->chan_net = get_net(net);
2720         chan->ppp = pch;
2721         init_ppp_file(&pch->file, CHANNEL);
2722         pch->file.hdrlen = chan->hdrlen;
2723 #ifdef CONFIG_PPP_MULTILINK
2724         pch->lastseq = -1;
2725 #endif /* CONFIG_PPP_MULTILINK */
2726         init_rwsem(&pch->chan_sem);
2727         spin_lock_init(&pch->downl);
2728         rwlock_init(&pch->upl);
2729
2730         spin_lock_bh(&pn->all_channels_lock);
2731         pch->file.index = ++pn->last_channel_index;
2732         list_add(&pch->list, &pn->new_channels);
2733         atomic_inc(&channel_count);
2734         spin_unlock_bh(&pn->all_channels_lock);
2735
2736         return 0;
2737 }
2738
2739 /*
2740  * Return the index of a channel.
2741  */
2742 int ppp_channel_index(struct ppp_channel *chan)
2743 {
2744         struct channel *pch = chan->ppp;
2745
2746         if (pch)
2747                 return pch->file.index;
2748         return -1;
2749 }
2750
2751 /*
2752  * Return the PPP unit number to which a channel is connected.
2753  */
2754 int ppp_unit_number(struct ppp_channel *chan)
2755 {
2756         struct channel *pch = chan->ppp;
2757         int unit = -1;
2758
2759         if (pch) {
2760                 read_lock_bh(&pch->upl);
2761                 if (pch->ppp)
2762                         unit = pch->ppp->file.index;
2763                 read_unlock_bh(&pch->upl);
2764         }
2765         return unit;
2766 }
2767
2768 /*
2769  * Return the PPP device interface name of a channel.
2770  */
2771 char *ppp_dev_name(struct ppp_channel *chan)
2772 {
2773         struct channel *pch = chan->ppp;
2774         char *name = NULL;
2775
2776         if (pch) {
2777                 read_lock_bh(&pch->upl);
2778                 if (pch->ppp && pch->ppp->dev)
2779                         name = pch->ppp->dev->name;
2780                 read_unlock_bh(&pch->upl);
2781         }
2782         return name;
2783 }
2784
2785
2786 /*
2787  * Disconnect a channel from the generic layer.
2788  * This must be called in process context.
2789  */
2790 void
2791 ppp_unregister_channel(struct ppp_channel *chan)
2792 {
2793         struct channel *pch = chan->ppp;
2794         struct ppp_net *pn;
2795
2796         if (!pch)
2797                 return;         /* should never happen */
2798
2799         chan->ppp = NULL;
2800
2801         /*
2802          * This ensures that we have returned from any calls into the
2803          * the channel's start_xmit or ioctl routine before we proceed.
2804          */
2805         down_write(&pch->chan_sem);
2806         spin_lock_bh(&pch->downl);
2807         pch->chan = NULL;
2808         spin_unlock_bh(&pch->downl);
2809         up_write(&pch->chan_sem);
2810         ppp_disconnect_channel(pch);
2811
2812         pn = ppp_pernet(pch->chan_net);
2813         spin_lock_bh(&pn->all_channels_lock);
2814         list_del(&pch->list);
2815         spin_unlock_bh(&pn->all_channels_lock);
2816
2817         pch->file.dead = 1;
2818         wake_up_interruptible(&pch->file.rwait);
2819         if (refcount_dec_and_test(&pch->file.refcnt))
2820                 ppp_destroy_channel(pch);
2821 }
2822
2823 /*
2824  * Callback from a channel when it can accept more to transmit.
2825  * This should be called at BH/softirq level, not interrupt level.
2826  */
2827 void
2828 ppp_output_wakeup(struct ppp_channel *chan)
2829 {
2830         struct channel *pch = chan->ppp;
2831
2832         if (!pch)
2833                 return;
2834         ppp_channel_push(pch);
2835 }
2836
2837 /*
2838  * Compression control.
2839  */
2840
2841 /* Process the PPPIOCSCOMPRESS ioctl. */
2842 static int
2843 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
2844 {
2845         int err = -EFAULT;
2846         struct compressor *cp, *ocomp;
2847         void *state, *ostate;
2848         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2849
2850         if (data->length > CCP_MAX_OPTION_LENGTH)
2851                 goto out;
2852         if (copy_from_user(ccp_option, data->ptr, data->length))
2853                 goto out;
2854
2855         err = -EINVAL;
2856         if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
2857                 goto out;
2858
2859         cp = try_then_request_module(
2860                 find_compressor(ccp_option[0]),
2861                 "ppp-compress-%d", ccp_option[0]);
2862         if (!cp)
2863                 goto out;
2864
2865         err = -ENOBUFS;
2866         if (data->transmit) {
2867                 state = cp->comp_alloc(ccp_option, data->length);
2868                 if (state) {
2869                         ppp_xmit_lock(ppp);
2870                         ppp->xstate &= ~SC_COMP_RUN;
2871                         ocomp = ppp->xcomp;
2872                         ostate = ppp->xc_state;
2873                         ppp->xcomp = cp;
2874                         ppp->xc_state = state;
2875                         ppp_xmit_unlock(ppp);
2876                         if (ostate) {
2877                                 ocomp->comp_free(ostate);
2878                                 module_put(ocomp->owner);
2879                         }
2880                         err = 0;
2881                 } else
2882                         module_put(cp->owner);
2883
2884         } else {
2885                 state = cp->decomp_alloc(ccp_option, data->length);
2886                 if (state) {
2887                         ppp_recv_lock(ppp);
2888                         ppp->rstate &= ~SC_DECOMP_RUN;
2889                         ocomp = ppp->rcomp;
2890                         ostate = ppp->rc_state;
2891                         ppp->rcomp = cp;
2892                         ppp->rc_state = state;
2893                         ppp_recv_unlock(ppp);
2894                         if (ostate) {
2895                                 ocomp->decomp_free(ostate);
2896                                 module_put(ocomp->owner);
2897                         }
2898                         err = 0;
2899                 } else
2900                         module_put(cp->owner);
2901         }
2902
2903  out:
2904         return err;
2905 }
2906
2907 /*
2908  * Look at a CCP packet and update our state accordingly.
2909  * We assume the caller has the xmit or recv path locked.
2910  */
2911 static void
2912 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2913 {
2914         unsigned char *dp;
2915         int len;
2916
2917         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2918                 return; /* no header */
2919         dp = skb->data + 2;
2920
2921         switch (CCP_CODE(dp)) {
2922         case CCP_CONFREQ:
2923
2924                 /* A ConfReq starts negotiation of compression
2925                  * in one direction of transmission,
2926                  * and hence brings it down...but which way?
2927                  *
2928                  * Remember:
2929                  * A ConfReq indicates what the sender would like to receive
2930                  */
2931                 if(inbound)
2932                         /* He is proposing what I should send */
2933                         ppp->xstate &= ~SC_COMP_RUN;
2934                 else
2935                         /* I am proposing to what he should send */
2936                         ppp->rstate &= ~SC_DECOMP_RUN;
2937
2938                 break;
2939
2940         case CCP_TERMREQ:
2941         case CCP_TERMACK:
2942                 /*
2943                  * CCP is going down, both directions of transmission
2944                  */
2945                 ppp->rstate &= ~SC_DECOMP_RUN;
2946                 ppp->xstate &= ~SC_COMP_RUN;
2947                 break;
2948
2949         case CCP_CONFACK:
2950                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2951                         break;
2952                 len = CCP_LENGTH(dp);
2953                 if (!pskb_may_pull(skb, len + 2))
2954                         return;         /* too short */
2955                 dp += CCP_HDRLEN;
2956                 len -= CCP_HDRLEN;
2957                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2958                         break;
2959                 if (inbound) {
2960                         /* we will start receiving compressed packets */
2961                         if (!ppp->rc_state)
2962                                 break;
2963                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2964                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2965                                 ppp->rstate |= SC_DECOMP_RUN;
2966                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2967                         }
2968                 } else {
2969                         /* we will soon start sending compressed packets */
2970                         if (!ppp->xc_state)
2971                                 break;
2972                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2973                                         ppp->file.index, 0, ppp->debug))
2974                                 ppp->xstate |= SC_COMP_RUN;
2975                 }
2976                 break;
2977
2978         case CCP_RESETACK:
2979                 /* reset the [de]compressor */
2980                 if ((ppp->flags & SC_CCP_UP) == 0)
2981                         break;
2982                 if (inbound) {
2983                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2984                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2985                                 ppp->rstate &= ~SC_DC_ERROR;
2986                         }
2987                 } else {
2988                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2989                                 ppp->xcomp->comp_reset(ppp->xc_state);
2990                 }
2991                 break;
2992         }
2993 }
2994
2995 /* Free up compression resources. */
2996 static void
2997 ppp_ccp_closed(struct ppp *ppp)
2998 {
2999         void *xstate, *rstate;
3000         struct compressor *xcomp, *rcomp;
3001
3002         ppp_lock(ppp);
3003         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3004         ppp->xstate = 0;
3005         xcomp = ppp->xcomp;
3006         xstate = ppp->xc_state;
3007         ppp->xc_state = NULL;
3008         ppp->rstate = 0;
3009         rcomp = ppp->rcomp;
3010         rstate = ppp->rc_state;
3011         ppp->rc_state = NULL;
3012         ppp_unlock(ppp);
3013
3014         if (xstate) {
3015                 xcomp->comp_free(xstate);
3016                 module_put(xcomp->owner);
3017         }
3018         if (rstate) {
3019                 rcomp->decomp_free(rstate);
3020                 module_put(rcomp->owner);
3021         }
3022 }
3023
3024 /* List of compressors. */
3025 static LIST_HEAD(compressor_list);
3026 static DEFINE_SPINLOCK(compressor_list_lock);
3027
3028 struct compressor_entry {
3029         struct list_head list;
3030         struct compressor *comp;
3031 };
3032
3033 static struct compressor_entry *
3034 find_comp_entry(int proto)
3035 {
3036         struct compressor_entry *ce;
3037
3038         list_for_each_entry(ce, &compressor_list, list) {
3039                 if (ce->comp->compress_proto == proto)
3040                         return ce;
3041         }
3042         return NULL;
3043 }
3044
3045 /* Register a compressor */
3046 int
3047 ppp_register_compressor(struct compressor *cp)
3048 {
3049         struct compressor_entry *ce;
3050         int ret;
3051         spin_lock(&compressor_list_lock);
3052         ret = -EEXIST;
3053         if (find_comp_entry(cp->compress_proto))
3054                 goto out;
3055         ret = -ENOMEM;
3056         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3057         if (!ce)
3058                 goto out;
3059         ret = 0;
3060         ce->comp = cp;
3061         list_add(&ce->list, &compressor_list);
3062  out:
3063         spin_unlock(&compressor_list_lock);
3064         return ret;
3065 }
3066
3067 /* Unregister a compressor */
3068 void
3069 ppp_unregister_compressor(struct compressor *cp)
3070 {
3071         struct compressor_entry *ce;
3072
3073         spin_lock(&compressor_list_lock);
3074         ce = find_comp_entry(cp->compress_proto);
3075         if (ce && ce->comp == cp) {
3076                 list_del(&ce->list);
3077                 kfree(ce);
3078         }
3079         spin_unlock(&compressor_list_lock);
3080 }
3081
3082 /* Find a compressor. */
3083 static struct compressor *
3084 find_compressor(int type)
3085 {
3086         struct compressor_entry *ce;
3087         struct compressor *cp = NULL;
3088
3089         spin_lock(&compressor_list_lock);
3090         ce = find_comp_entry(type);
3091         if (ce) {
3092                 cp = ce->comp;
3093                 if (!try_module_get(cp->owner))
3094                         cp = NULL;
3095         }
3096         spin_unlock(&compressor_list_lock);
3097         return cp;
3098 }
3099
3100 /*
3101  * Miscelleneous stuff.
3102  */
3103
3104 static void
3105 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3106 {
3107         struct slcompress *vj = ppp->vj;
3108
3109         memset(st, 0, sizeof(*st));
3110         st->p.ppp_ipackets = ppp->stats64.rx_packets;
3111         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3112         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3113         st->p.ppp_opackets = ppp->stats64.tx_packets;
3114         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3115         st->p.ppp_obytes = ppp->stats64.tx_bytes;
3116         if (!vj)
3117                 return;
3118         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3119         st->vj.vjs_compressed = vj->sls_o_compressed;
3120         st->vj.vjs_searches = vj->sls_o_searches;
3121         st->vj.vjs_misses = vj->sls_o_misses;
3122         st->vj.vjs_errorin = vj->sls_i_error;
3123         st->vj.vjs_tossed = vj->sls_i_tossed;
3124         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3125         st->vj.vjs_compressedin = vj->sls_i_compressed;
3126 }
3127
3128 /*
3129  * Stuff for handling the lists of ppp units and channels
3130  * and for initialization.
3131  */
3132
3133 /*
3134  * Create a new ppp interface unit.  Fails if it can't allocate memory
3135  * or if there is already a unit with the requested number.
3136  * unit == -1 means allocate a new number.
3137  */
3138 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3139 {
3140         struct ppp_config conf = {
3141                 .file = file,
3142                 .unit = *unit,
3143                 .ifname_is_set = false,
3144         };
3145         struct net_device *dev;
3146         struct ppp *ppp;
3147         int err;
3148
3149         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3150         if (!dev) {
3151                 err = -ENOMEM;
3152                 goto err;
3153         }
3154         dev_net_set(dev, net);
3155         dev->rtnl_link_ops = &ppp_link_ops;
3156
3157         rtnl_lock();
3158
3159         err = ppp_dev_configure(net, dev, &conf);
3160         if (err < 0)
3161                 goto err_dev;
3162         ppp = netdev_priv(dev);
3163         *unit = ppp->file.index;
3164
3165         rtnl_unlock();
3166
3167         return 0;
3168
3169 err_dev:
3170         rtnl_unlock();
3171         free_netdev(dev);
3172 err:
3173         return err;
3174 }
3175
3176 /*
3177  * Initialize a ppp_file structure.
3178  */
3179 static void
3180 init_ppp_file(struct ppp_file *pf, int kind)
3181 {
3182         pf->kind = kind;
3183         skb_queue_head_init(&pf->xq);
3184         skb_queue_head_init(&pf->rq);
3185         refcount_set(&pf->refcnt, 1);
3186         init_waitqueue_head(&pf->rwait);
3187 }
3188
3189 /*
3190  * Free the memory used by a ppp unit.  This is only called once
3191  * there are no channels connected to the unit and no file structs
3192  * that reference the unit.
3193  */
3194 static void ppp_destroy_interface(struct ppp *ppp)
3195 {
3196         atomic_dec(&ppp_unit_count);
3197
3198         if (!ppp->file.dead || ppp->n_channels) {
3199                 /* "can't happen" */
3200                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3201                            "but dead=%d n_channels=%d !\n",
3202                            ppp, ppp->file.dead, ppp->n_channels);
3203                 return;
3204         }
3205
3206         ppp_ccp_closed(ppp);
3207         if (ppp->vj) {
3208                 slhc_free(ppp->vj);
3209                 ppp->vj = NULL;
3210         }
3211         skb_queue_purge(&ppp->file.xq);
3212         skb_queue_purge(&ppp->file.rq);
3213 #ifdef CONFIG_PPP_MULTILINK
3214         skb_queue_purge(&ppp->mrq);
3215 #endif /* CONFIG_PPP_MULTILINK */
3216 #ifdef CONFIG_PPP_FILTER
3217         if (ppp->pass_filter) {
3218                 bpf_prog_destroy(ppp->pass_filter);
3219                 ppp->pass_filter = NULL;
3220         }
3221
3222         if (ppp->active_filter) {
3223                 bpf_prog_destroy(ppp->active_filter);
3224                 ppp->active_filter = NULL;
3225         }
3226 #endif /* CONFIG_PPP_FILTER */
3227
3228         kfree_skb(ppp->xmit_pending);
3229         free_percpu(ppp->xmit_recursion);
3230
3231         free_netdev(ppp->dev);
3232 }
3233
3234 /*
3235  * Locate an existing ppp unit.
3236  * The caller should have locked the all_ppp_mutex.
3237  */
3238 static struct ppp *
3239 ppp_find_unit(struct ppp_net *pn, int unit)
3240 {
3241         return unit_find(&pn->units_idr, unit);
3242 }
3243
3244 /*
3245  * Locate an existing ppp channel.
3246  * The caller should have locked the all_channels_lock.
3247  * First we look in the new_channels list, then in the
3248  * all_channels list.  If found in the new_channels list,
3249  * we move it to the all_channels list.  This is for speed
3250  * when we have a lot of channels in use.
3251  */
3252 static struct channel *
3253 ppp_find_channel(struct ppp_net *pn, int unit)
3254 {
3255         struct channel *pch;
3256
3257         list_for_each_entry(pch, &pn->new_channels, list) {
3258                 if (pch->file.index == unit) {
3259                         list_move(&pch->list, &pn->all_channels);
3260                         return pch;
3261                 }
3262         }
3263
3264         list_for_each_entry(pch, &pn->all_channels, list) {
3265                 if (pch->file.index == unit)
3266                         return pch;
3267         }
3268
3269         return NULL;
3270 }
3271
3272 /*
3273  * Connect a PPP channel to a PPP interface unit.
3274  */
3275 static int
3276 ppp_connect_channel(struct channel *pch, int unit)
3277 {
3278         struct ppp *ppp;
3279         struct ppp_net *pn;
3280         int ret = -ENXIO;
3281         int hdrlen;
3282
3283         pn = ppp_pernet(pch->chan_net);
3284
3285         mutex_lock(&pn->all_ppp_mutex);
3286         ppp = ppp_find_unit(pn, unit);
3287         if (!ppp)
3288                 goto out;
3289         write_lock_bh(&pch->upl);
3290         ret = -EINVAL;
3291         if (pch->ppp)
3292                 goto outl;
3293
3294         ppp_lock(ppp);
3295         spin_lock_bh(&pch->downl);
3296         if (!pch->chan) {
3297                 /* Don't connect unregistered channels */
3298                 spin_unlock_bh(&pch->downl);
3299                 ppp_unlock(ppp);
3300                 ret = -ENOTCONN;
3301                 goto outl;
3302         }
3303         spin_unlock_bh(&pch->downl);
3304         if (pch->file.hdrlen > ppp->file.hdrlen)
3305                 ppp->file.hdrlen = pch->file.hdrlen;
3306         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3307         if (hdrlen > ppp->dev->hard_header_len)
3308                 ppp->dev->hard_header_len = hdrlen;
3309         list_add_tail(&pch->clist, &ppp->channels);
3310         ++ppp->n_channels;
3311         pch->ppp = ppp;
3312         refcount_inc(&ppp->file.refcnt);
3313         ppp_unlock(ppp);
3314         ret = 0;
3315
3316  outl:
3317         write_unlock_bh(&pch->upl);
3318  out:
3319         mutex_unlock(&pn->all_ppp_mutex);
3320         return ret;
3321 }
3322
3323 /*
3324  * Disconnect a channel from its ppp unit.
3325  */
3326 static int
3327 ppp_disconnect_channel(struct channel *pch)
3328 {
3329         struct ppp *ppp;
3330         int err = -EINVAL;
3331
3332         write_lock_bh(&pch->upl);
3333         ppp = pch->ppp;
3334         pch->ppp = NULL;
3335         write_unlock_bh(&pch->upl);
3336         if (ppp) {
3337                 /* remove it from the ppp unit's list */
3338                 ppp_lock(ppp);
3339                 list_del(&pch->clist);
3340                 if (--ppp->n_channels == 0)
3341                         wake_up_interruptible(&ppp->file.rwait);
3342                 ppp_unlock(ppp);
3343                 if (refcount_dec_and_test(&ppp->file.refcnt))
3344                         ppp_destroy_interface(ppp);
3345                 err = 0;
3346         }
3347         return err;
3348 }
3349
3350 /*
3351  * Free up the resources used by a ppp channel.
3352  */
3353 static void ppp_destroy_channel(struct channel *pch)
3354 {
3355         put_net(pch->chan_net);
3356         pch->chan_net = NULL;
3357
3358         atomic_dec(&channel_count);
3359
3360         if (!pch->file.dead) {
3361                 /* "can't happen" */
3362                 pr_err("ppp: destroying undead channel %p !\n", pch);
3363                 return;
3364         }
3365         skb_queue_purge(&pch->file.xq);
3366         skb_queue_purge(&pch->file.rq);
3367         kfree(pch);
3368 }
3369
3370 static void __exit ppp_cleanup(void)
3371 {
3372         /* should never happen */
3373         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3374                 pr_err("PPP: removing module but units remain!\n");
3375         rtnl_link_unregister(&ppp_link_ops);
3376         unregister_chrdev(PPP_MAJOR, "ppp");
3377         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3378         class_destroy(ppp_class);
3379         unregister_pernet_device(&ppp_net_ops);
3380 }
3381
3382 /*
3383  * Units handling. Caller must protect concurrent access
3384  * by holding all_ppp_mutex
3385  */
3386
3387 /* associate pointer with specified number */
3388 static int unit_set(struct idr *p, void *ptr, int n)
3389 {
3390         int unit;
3391
3392         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3393         if (unit == -ENOSPC)
3394                 unit = -EINVAL;
3395         return unit;
3396 }
3397
3398 /* get new free unit number and associate pointer with it */
3399 static int unit_get(struct idr *p, void *ptr, int min)
3400 {
3401         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3402 }
3403
3404 /* put unit number back to a pool */
3405 static void unit_put(struct idr *p, int n)
3406 {
3407         idr_remove(p, n);
3408 }
3409
3410 /* get pointer associated with the number */
3411 static void *unit_find(struct idr *p, int n)
3412 {
3413         return idr_find(p, n);
3414 }
3415
3416 /* Module/initialization stuff */
3417
3418 module_init(ppp_init);
3419 module_exit(ppp_cleanup);
3420
3421 EXPORT_SYMBOL(ppp_register_net_channel);
3422 EXPORT_SYMBOL(ppp_register_channel);
3423 EXPORT_SYMBOL(ppp_unregister_channel);
3424 EXPORT_SYMBOL(ppp_channel_index);
3425 EXPORT_SYMBOL(ppp_unit_number);
3426 EXPORT_SYMBOL(ppp_dev_name);
3427 EXPORT_SYMBOL(ppp_input);
3428 EXPORT_SYMBOL(ppp_input_error);
3429 EXPORT_SYMBOL(ppp_output_wakeup);
3430 EXPORT_SYMBOL(ppp_register_compressor);
3431 EXPORT_SYMBOL(ppp_unregister_compressor);
3432 MODULE_LICENSE("GPL");
3433 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3434 MODULE_ALIAS_RTNL_LINK("ppp");
3435 MODULE_ALIAS("devname:ppp");