kernel/drivers/net/ppp/ppp_generic.c

   1 /*
   2  * Generic PPP layer for Linux.
   3  *
   4  * Copyright 1999-2002 Paul Mackerras.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  *
  11  * The generic PPP layer handles the PPP network interfaces, the
  12  * /dev/ppp device, packet and VJ compression, and multilink.
  13  * It talks to PPP `channels' via the interface defined in
  14  * include/linux/ppp_channel.h.  Channels provide the basic means for
  15  * sending and receiving PPP frames on some kind of communications
  16  * channel.
  17  *
  18  * Part of the code in this driver was inspired by the old async-only
  19  * PPP driver, written by Michael Callahan and Al Longyear, and
  20  * subsequently hacked by Paul Mackerras.
  21  *
  22  * ==FILEVERSION 20041108==
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/kmod.h>
  28 #include <linux/init.h>
  29 #include <linux/list.h>
  30 #include <linux/idr.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/poll.h>
  33 #include <linux/ppp_defs.h>
  34 #include <linux/filter.h>
  35 #include <linux/ppp-ioctl.h>
  36 #include <linux/ppp_channel.h>
  37 #include <linux/ppp-comp.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/rtnetlink.h>
  40 #include <linux/if_arp.h>
  41 #include <linux/ip.h>
  42 #include <linux/tcp.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/rwsem.h>
  45 #include <linux/stddef.h>
  46 #include <linux/device.h>
  47 #include <linux/mutex.h>
  48 #include <linux/slab.h>
  49 #include <asm/unaligned.h>
  50 #include <net/slhc_vj.h>
  51 #include <linux/atomic.h>
  52
  53 #include <linux/nsproxy.h>
  54 #include <net/net_namespace.h>
  55 #include <net/netns/generic.h>
  56
  57 #define PPP_VERSION     "2.4.2"
  58
  59 /*
  60  * Network protocols we support.
  61  */
  62 #define NP_IP   0               /* Internet Protocol V4 */
  63 #define NP_IPV6 1               /* Internet Protocol V6 */
  64 #define NP_IPX  2               /* IPX protocol */
  65 #define NP_AT   3               /* Appletalk protocol */
  66 #define NP_MPLS_UC 4            /* MPLS unicast */
  67 #define NP_MPLS_MC 5            /* MPLS multicast */
  68 #define NUM_NP  6               /* Number of NPs. */
  69
  70 #define MPHDRLEN        6       /* multilink protocol header length */
  71 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  72
  73 /*
  74  * An instance of /dev/ppp can be associated with either a ppp
  75  * interface unit or a ppp channel.  In both cases, file->private_data
  76  * points to one of these.
  77  */
  78 struct ppp_file {
  79         enum {
  80                 INTERFACE=1, CHANNEL
  81         }               kind;
  82         struct sk_buff_head xq;         /* pppd transmit queue */
  83         struct sk_buff_head rq;         /* receive queue for pppd */
  84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  86         int             hdrlen;         /* space to leave for headers */
  87         int             index;          /* interface unit / channel number */
  88         int             dead;           /* unit/channel has been shut down */
  89 };
  90
  91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  92
  93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  95
  96 /*
  97  * Data structure to hold primary network stats for which
  98  * we want to use 64 bit storage.  Other network stats
  99  * are stored in dev->stats of the ppp strucute.
 100  */
 101 struct ppp_link_stats {
 102         u64 rx_packets;
 103         u64 tx_packets;
 104         u64 rx_bytes;
 105         u64 tx_bytes;
 106 };
 107
 108 /*
 109  * Data structure describing one ppp unit.
 110  * A ppp unit corresponds to a ppp network interface device
 111  * and represents a multilink bundle.
 112  * It can have 0 or more ppp channels connected to it.
 113  */
 114 struct ppp {
 115         struct ppp_file file;           /* stuff for read/write/poll 0 */
 116         struct file     *owner;         /* file that owns this unit 48 */
 117         struct list_head channels;      /* list of attached channels 4c */
 118         int             n_channels;     /* how many channels are attached 54 */
 119         spinlock_t      rlock;          /* lock for receive side 58 */
 120         spinlock_t      wlock;          /* lock for transmit side 5c */
 121         int             mru;            /* max receive unit 60 */
 122         unsigned int    flags;          /* control bits 64 */
 123         unsigned int    xstate;         /* transmit state bits 68 */
 124         unsigned int    rstate;         /* receive state bits 6c */
 125         int             debug;          /* debug flags 70 */
 126         struct slcompress *vj;          /* state for VJ header compression */
 127         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 128         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 129         struct compressor *xcomp;       /* transmit packet compressor 8c */
 130         void            *xc_state;      /* its internal state 90 */
 131         struct compressor *rcomp;       /* receive decompressor 94 */
 132         void            *rc_state;      /* its internal state 98 */
 133         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 134         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 135         struct net_device *dev;         /* network interface device a4 */
 136         int             closing;        /* is device closing down? a8 */
 137 #ifdef CONFIG_PPP_MULTILINK
 138         int             nxchan;         /* next channel to send something on */
 139         u32             nxseq;          /* next sequence number to send */
 140         int             mrru;           /* MP: max reconst. receive unit */
 141         u32             nextseq;        /* MP: seq no of next packet */
 142         u32             minseq;         /* MP: min of most recent seqnos */
 143         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 144 #endif /* CONFIG_PPP_MULTILINK */
 145 #ifdef CONFIG_PPP_FILTER
 146         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 147         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 148 #endif /* CONFIG_PPP_FILTER */
 149         struct net      *ppp_net;       /* the net we belong to */
 150         struct ppp_link_stats stats64;  /* 64 bit network stats */
 151 };
 152
 153 /*
 154  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 155  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 156  * SC_MUST_COMP
 157  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 158  * Bits in xstate: SC_COMP_RUN
 159  */
 160 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 161                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 162                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 163
 164 /*
 165  * Private data structure for each channel.
 166  * This includes the data structure used for multilink.
 167  */
 168 struct channel {
 169         struct ppp_file file;           /* stuff for read/write/poll */
 170         struct list_head list;          /* link in all/new_channels list */
 171         struct ppp_channel *chan;       /* public channel data structure */
 172         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 173         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 174         struct ppp      *ppp;           /* ppp unit we're connected to */
 175         struct net      *chan_net;      /* the net channel belongs to */
 176         struct list_head clist;         /* link in list of channels per unit */
 177         rwlock_t        upl;            /* protects `ppp' */
 178 #ifdef CONFIG_PPP_MULTILINK
 179         u8              avail;          /* flag used in multilink stuff */
 180         u8              had_frag;       /* >= 1 fragments have been sent */
 181         u32             lastseq;        /* MP: last sequence # received */
 182         int             speed;          /* speed of the corresponding ppp channel*/
 183 #endif /* CONFIG_PPP_MULTILINK */
 184 };
 185
 186 /*
 187  * SMP locking issues:
 188  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 189  * list and the ppp.n_channels field, you need to take both locks
 190  * before you modify them.
 191  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 192  * channel.downl.
 193  */
 194
 195 static DEFINE_MUTEX(ppp_mutex);
 196 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 197 static atomic_t channel_count = ATOMIC_INIT(0);
 198
 199 /* per-net private data for this module */
 200 static int ppp_net_id __read_mostly;
 201 struct ppp_net {
 202         /* units to ppp mapping */
 203         struct idr units_idr;
 204
 205         /*
 206          * all_ppp_mutex protects the units_idr mapping.
 207          * It also ensures that finding a ppp unit in the units_idr
 208          * map and updating its file.refcnt field is atomic.
 209          */
 210         struct mutex all_ppp_mutex;
 211
 212         /* channels */
 213         struct list_head all_channels;
 214         struct list_head new_channels;
 215         int last_channel_index;
 216
 217         /*
 218          * all_channels_lock protects all_channels and
 219          * last_channel_index, and the atomicity of find
 220          * a channel and updating its file.refcnt field.
 221          */
 222         spinlock_t all_channels_lock;
 223 };
 224
 225 /* Get the PPP protocol number from a skb */
 226 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 227
 228 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 229 #define PPP_MAX_RQLEN   32
 230
 231 /*
 232  * Maximum number of multilink fragments queued up.
 233  * This has to be large enough to cope with the maximum latency of
 234  * the slowest channel relative to the others.  Strictly it should
 235  * depend on the number of channels and their characteristics.
 236  */
 237 #define PPP_MP_MAX_QLEN 128
 238
 239 /* Multilink header bits. */
 240 #define B       0x80            /* this fragment begins a packet */
 241 #define E       0x40            /* this fragment ends a packet */
 242
 243 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 244 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 245 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 246
 247 /* Prototypes. */
 248 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 249                         struct file *file, unsigned int cmd, unsigned long arg);
 250 static void ppp_xmit_process(struct ppp *ppp);
 251 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 252 static void ppp_push(struct ppp *ppp);
 253 static void ppp_channel_push(struct channel *pch);
 254 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 255                               struct channel *pch);
 256 static void ppp_receive_error(struct ppp *ppp);
 257 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 258 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 259                                             struct sk_buff *skb);
 260 #ifdef CONFIG_PPP_MULTILINK
 261 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 262                                 struct channel *pch);
 263 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 264 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 265 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 266 #endif /* CONFIG_PPP_MULTILINK */
 267 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 268 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 269 static void ppp_ccp_closed(struct ppp *ppp);
 270 static struct compressor *find_compressor(int type);
 271 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 272 static struct ppp *ppp_create_interface(struct net *net, int unit,
 273                                         struct file *file, int *retp);
 274 static void init_ppp_file(struct ppp_file *pf, int kind);
 275 static void ppp_destroy_interface(struct ppp *ppp);
 276 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 277 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 278 static int ppp_connect_channel(struct channel *pch, int unit);
 279 static int ppp_disconnect_channel(struct channel *pch);
 280 static void ppp_destroy_channel(struct channel *pch);
 281 static int unit_get(struct idr *p, void *ptr);
 282 static int unit_set(struct idr *p, void *ptr, int n);
 283 static void unit_put(struct idr *p, int n);
 284 static void *unit_find(struct idr *p, int n);
 285
 286 static const struct net_device_ops ppp_netdev_ops;
 287
 288 static struct class *ppp_class;
 289
 290 /* per net-namespace data */
 291 static inline struct ppp_net *ppp_pernet(struct net *net)
 292 {
 293         BUG_ON(!net);
 294
 295         return net_generic(net, ppp_net_id);
 296 }
 297
 298 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 299 static inline int proto_to_npindex(int proto)
 300 {
 301         switch (proto) {
 302         case PPP_IP:
 303                 return NP_IP;
 304         case PPP_IPV6:
 305                 return NP_IPV6;
 306         case PPP_IPX:
 307                 return NP_IPX;
 308         case PPP_AT:
 309                 return NP_AT;
 310         case PPP_MPLS_UC:
 311                 return NP_MPLS_UC;
 312         case PPP_MPLS_MC:
 313                 return NP_MPLS_MC;
 314         }
 315         return -EINVAL;
 316 }
 317
 318 /* Translates an NP index into a PPP protocol number */
 319 static const int npindex_to_proto[NUM_NP] = {
 320         PPP_IP,
 321         PPP_IPV6,
 322         PPP_IPX,
 323         PPP_AT,
 324         PPP_MPLS_UC,
 325         PPP_MPLS_MC,
 326 };
 327
 328 /* Translates an ethertype into an NP index */
 329 static inline int ethertype_to_npindex(int ethertype)
 330 {
 331         switch (ethertype) {
 332         case ETH_P_IP:
 333                 return NP_IP;
 334         case ETH_P_IPV6:
 335                 return NP_IPV6;
 336         case ETH_P_IPX:
 337                 return NP_IPX;
 338         case ETH_P_PPPTALK:
 339         case ETH_P_ATALK:
 340                 return NP_AT;
 341         case ETH_P_MPLS_UC:
 342                 return NP_MPLS_UC;
 343         case ETH_P_MPLS_MC:
 344                 return NP_MPLS_MC;
 345         }
 346         return -1;
 347 }
 348
 349 /* Translates an NP index into an ethertype */
 350 static const int npindex_to_ethertype[NUM_NP] = {
 351         ETH_P_IP,
 352         ETH_P_IPV6,
 353         ETH_P_IPX,
 354         ETH_P_PPPTALK,
 355         ETH_P_MPLS_UC,
 356         ETH_P_MPLS_MC,
 357 };
 358
 359 /*
 360  * Locking shorthand.
 361  */
 362 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 363 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 364 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 365 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 366 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 367                                      ppp_recv_lock(ppp); } while (0)
 368 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 369                                      ppp_xmit_unlock(ppp); } while (0)
 370
 371 /*
 372  * /dev/ppp device routines.
 373  * The /dev/ppp device is used by pppd to control the ppp unit.
 374  * It supports the read, write, ioctl and poll functions.
 375  * Open instances of /dev/ppp can be in one of three states:
 376  * unattached, attached to a ppp unit, or attached to a ppp channel.
 377  */
 378 static int ppp_open(struct inode *inode, struct file *file)
 379 {
 380         /*
 381          * This could (should?) be enforced by the permissions on /dev/ppp.
 382          */
 383         if (!capable(CAP_NET_ADMIN))
 384                 return -EPERM;
 385         return 0;
 386 }
 387
 388 static int ppp_release(struct inode *unused, struct file *file)
 389 {
 390         struct ppp_file *pf = file->private_data;
 391         struct ppp *ppp;
 392
 393         if (pf) {
 394                 file->private_data = NULL;
 395                 if (pf->kind == INTERFACE) {
 396                         ppp = PF_TO_PPP(pf);
 397                         rtnl_lock();
 398                         if (file == ppp->owner)
 399                                 unregister_netdevice(ppp->dev);
 400                         rtnl_unlock();
 401                 }
 402                 if (atomic_dec_and_test(&pf->refcnt)) {
 403                         switch (pf->kind) {
 404                         case INTERFACE:
 405                                 ppp_destroy_interface(PF_TO_PPP(pf));
 406                                 break;
 407                         case CHANNEL:
 408                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 409                                 break;
 410                         }
 411                 }
 412         }
 413         return 0;
 414 }
 415
 416 static ssize_t ppp_read(struct file *file, char __user *buf,
 417                         size_t count, loff_t *ppos)
 418 {
 419         struct ppp_file *pf = file->private_data;
 420         DECLARE_WAITQUEUE(wait, current);
 421         ssize_t ret;
 422         struct sk_buff *skb = NULL;
 423         struct iovec iov;
 424         struct iov_iter to;
 425
 426         ret = count;
 427
 428         if (!pf)
 429                 return -ENXIO;
 430         add_wait_queue(&pf->rwait, &wait);
 431         for (;;) {
 432                 set_current_state(TASK_INTERRUPTIBLE);
 433                 skb = skb_dequeue(&pf->rq);
 434                 if (skb)
 435                         break;
 436                 ret = 0;
 437                 if (pf->dead)
 438                         break;
 439                 if (pf->kind == INTERFACE) {
 440                         /*
 441                          * Return 0 (EOF) on an interface that has no
 442                          * channels connected, unless it is looping
 443                          * network traffic (demand mode).
 444                          */
 445                         struct ppp *ppp = PF_TO_PPP(pf);
 446                         if (ppp->n_channels == 0 &&
 447                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 448                                 break;
 449                 }
 450                 ret = -EAGAIN;
 451                 if (file->f_flags & O_NONBLOCK)
 452                         break;
 453                 ret = -ERESTARTSYS;
 454                 if (signal_pending(current))
 455                         break;
 456                 schedule();
 457         }
 458         set_current_state(TASK_RUNNING);
 459         remove_wait_queue(&pf->rwait, &wait);
 460
 461         if (!skb)
 462                 goto out;
 463
 464         ret = -EOVERFLOW;
 465         if (skb->len > count)
 466                 goto outf;
 467         ret = -EFAULT;
 468         iov.iov_base = buf;
 469         iov.iov_len = count;
 470         iov_iter_init(&to, READ, &iov, 1, count);
 471         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 472                 goto outf;
 473         ret = skb->len;
 474
 475  outf:
 476         kfree_skb(skb);
 477  out:
 478         return ret;
 479 }
 480
 481 static ssize_t ppp_write(struct file *file, const char __user *buf,
 482                          size_t count, loff_t *ppos)
 483 {
 484         struct ppp_file *pf = file->private_data;
 485         struct sk_buff *skb;
 486         ssize_t ret;
 487
 488         if (!pf)
 489                 return -ENXIO;
 490         ret = -ENOMEM;
 491         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 492         if (!skb)
 493                 goto out;
 494         skb_reserve(skb, pf->hdrlen);
 495         ret = -EFAULT;
 496         if (copy_from_user(skb_put(skb, count), buf, count)) {
 497                 kfree_skb(skb);
 498                 goto out;
 499         }
 500
 501         skb_queue_tail(&pf->xq, skb);
 502
 503         switch (pf->kind) {
 504         case INTERFACE:
 505                 ppp_xmit_process(PF_TO_PPP(pf));
 506                 break;
 507         case CHANNEL:
 508                 ppp_channel_push(PF_TO_CHANNEL(pf));
 509                 break;
 510         }
 511
 512         ret = count;
 513
 514  out:
 515         return ret;
 516 }
 517
 518 /* No kernel lock - fine */
 519 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 520 {
 521         struct ppp_file *pf = file->private_data;
 522         unsigned int mask;
 523
 524         if (!pf)
 525                 return 0;
 526         poll_wait(file, &pf->rwait, wait);
 527         mask = POLLOUT | POLLWRNORM;
 528         if (skb_peek(&pf->rq))
 529                 mask |= POLLIN | POLLRDNORM;
 530         if (pf->dead)
 531                 mask |= POLLHUP;
 532         else if (pf->kind == INTERFACE) {
 533                 /* see comment in ppp_read */
 534                 struct ppp *ppp = PF_TO_PPP(pf);
 535                 if (ppp->n_channels == 0 &&
 536                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 537                         mask |= POLLIN | POLLRDNORM;
 538         }
 539
 540         return mask;
 541 }
 542
 543 #ifdef CONFIG_PPP_FILTER
 544 static int get_filter(void __user *arg, struct sock_filter **p)
 545 {
 546         struct sock_fprog uprog;
 547         struct sock_filter *code = NULL;
 548         int len;
 549
 550         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 551                 return -EFAULT;
 552
 553         if (!uprog.len) {
 554                 *p = NULL;
 555                 return 0;
 556         }
 557
 558         len = uprog.len * sizeof(struct sock_filter);
 559         code = memdup_user(uprog.filter, len);
 560         if (IS_ERR(code))
 561                 return PTR_ERR(code);
 562
 563         *p = code;
 564         return uprog.len;
 565 }
 566 #endif /* CONFIG_PPP_FILTER */
 567
 568 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 569 {
 570         struct ppp_file *pf;
 571         struct ppp *ppp;
 572         int err = -EFAULT, val, val2, i;
 573         struct ppp_idle idle;
 574         struct npioctl npi;
 575         int unit, cflags;
 576         struct slcompress *vj;
 577         void __user *argp = (void __user *)arg;
 578         int __user *p = argp;
 579
 580         mutex_lock(&ppp_mutex);
 581
 582         pf = file->private_data;
 583         if (!pf) {
 584                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 585                                            pf, file, cmd, arg);
 586                 goto out;
 587         }
 588
 589         if (cmd == PPPIOCDETACH) {
 590                 /*
 591                  * We have to be careful here... if the file descriptor
 592                  * has been dup'd, we could have another process in the
 593                  * middle of a poll using the same file *, so we had
 594                  * better not free the interface data structures -
 595                  * instead we fail the ioctl.  Even in this case, we
 596                  * shut down the interface if we are the owner of it.
 597                  * Actually, we should get rid of PPPIOCDETACH, userland
 598                  * (i.e. pppd) could achieve the same effect by closing
 599                  * this fd and reopening /dev/ppp.
 600                  */
 601                 err = -EINVAL;
 602                 if (pf->kind == INTERFACE) {
 603                         ppp = PF_TO_PPP(pf);
 604                         rtnl_lock();
 605                         if (file == ppp->owner)
 606                                 unregister_netdevice(ppp->dev);
 607                         rtnl_unlock();
 608                 }
 609                 if (atomic_long_read(&file->f_count) < 2) {
 610                         ppp_release(NULL, file);
 611                         err = 0;
 612                 } else
 613                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 614                                 atomic_long_read(&file->f_count));
 615                 goto out;
 616         }
 617
 618         if (pf->kind == CHANNEL) {
 619                 struct channel *pch;
 620                 struct ppp_channel *chan;
 621
 622                 pch = PF_TO_CHANNEL(pf);
 623
 624                 switch (cmd) {
 625                 case PPPIOCCONNECT:
 626                         if (get_user(unit, p))
 627                                 break;
 628                         err = ppp_connect_channel(pch, unit);
 629                         break;
 630
 631                 case PPPIOCDISCONN:
 632                         err = ppp_disconnect_channel(pch);
 633                         break;
 634
 635                 default:
 636                         down_read(&pch->chan_sem);
 637                         chan = pch->chan;
 638                         err = -ENOTTY;
 639                         if (chan && chan->ops->ioctl)
 640                                 err = chan->ops->ioctl(chan, cmd, arg);
 641                         up_read(&pch->chan_sem);
 642                 }
 643                 goto out;
 644         }
 645
 646         if (pf->kind != INTERFACE) {
 647                 /* can't happen */
 648                 pr_err("PPP: not interface or channel??\n");
 649                 err = -EINVAL;
 650                 goto out;
 651         }
 652
 653         ppp = PF_TO_PPP(pf);
 654         switch (cmd) {
 655         case PPPIOCSMRU:
 656                 if (get_user(val, p))
 657                         break;
 658                 ppp->mru = val;
 659                 err = 0;
 660                 break;
 661
 662         case PPPIOCSFLAGS:
 663                 if (get_user(val, p))
 664                         break;
 665                 ppp_lock(ppp);
 666                 cflags = ppp->flags & ~val;
 667 #ifdef CONFIG_PPP_MULTILINK
 668                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 669                         ppp->nextseq = 0;
 670 #endif
 671                 ppp->flags = val & SC_FLAG_BITS;
 672                 ppp_unlock(ppp);
 673                 if (cflags & SC_CCP_OPEN)
 674                         ppp_ccp_closed(ppp);
 675                 err = 0;
 676                 break;
 677
 678         case PPPIOCGFLAGS:
 679                 val = ppp->flags | ppp->xstate | ppp->rstate;
 680                 if (put_user(val, p))
 681                         break;
 682                 err = 0;
 683                 break;
 684
 685         case PPPIOCSCOMPRESS:
 686                 err = ppp_set_compress(ppp, arg);
 687                 break;
 688
 689         case PPPIOCGUNIT:
 690                 if (put_user(ppp->file.index, p))
 691                         break;
 692                 err = 0;
 693                 break;
 694
 695         case PPPIOCSDEBUG:
 696                 if (get_user(val, p))
 697                         break;
 698                 ppp->debug = val;
 699                 err = 0;
 700                 break;
 701
 702         case PPPIOCGDEBUG:
 703                 if (put_user(ppp->debug, p))
 704                         break;
 705                 err = 0;
 706                 break;
 707
 708         case PPPIOCGIDLE:
 709                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 710                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 711                 if (copy_to_user(argp, &idle, sizeof(idle)))
 712                         break;
 713                 err = 0;
 714                 break;
 715
 716         case PPPIOCSMAXCID:
 717                 if (get_user(val, p))
 718                         break;
 719                 val2 = 15;
 720                 if ((val >> 16) != 0) {
 721                         val2 = val >> 16;
 722                         val &= 0xffff;
 723                 }
 724                 vj = slhc_init(val2+1, val+1);
 725                 if (IS_ERR(vj)) {
 726                         err = PTR_ERR(vj);
 727                         break;
 728                 }
 729                 ppp_lock(ppp);
 730                 if (ppp->vj)
 731                         slhc_free(ppp->vj);
 732                 ppp->vj = vj;
 733                 ppp_unlock(ppp);
 734                 err = 0;
 735                 break;
 736
 737         case PPPIOCGNPMODE:
 738         case PPPIOCSNPMODE:
 739                 if (copy_from_user(&npi, argp, sizeof(npi)))
 740                         break;
 741                 err = proto_to_npindex(npi.protocol);
 742                 if (err < 0)
 743                         break;
 744                 i = err;
 745                 if (cmd == PPPIOCGNPMODE) {
 746                         err = -EFAULT;
 747                         npi.mode = ppp->npmode[i];
 748                         if (copy_to_user(argp, &npi, sizeof(npi)))
 749                                 break;
 750                 } else {
 751                         ppp->npmode[i] = npi.mode;
 752                         /* we may be able to transmit more packets now (??) */
 753                         netif_wake_queue(ppp->dev);
 754                 }
 755                 err = 0;
 756                 break;
 757
 758 #ifdef CONFIG_PPP_FILTER
 759         case PPPIOCSPASS:
 760         {
 761                 struct sock_filter *code;
 762
 763                 err = get_filter(argp, &code);
 764                 if (err >= 0) {
 765                         struct bpf_prog *pass_filter = NULL;
 766                         struct sock_fprog_kern fprog = {
 767                                 .len = err,
 768                                 .filter = code,
 769                         };
 770
 771                         err = 0;
 772                         if (fprog.filter)
 773                                 err = bpf_prog_create(&pass_filter, &fprog);
 774                         if (!err) {
 775                                 ppp_lock(ppp);
 776                                 if (ppp->pass_filter)
 777                                         bpf_prog_destroy(ppp->pass_filter);
 778                                 ppp->pass_filter = pass_filter;
 779                                 ppp_unlock(ppp);
 780                         }
 781                         kfree(code);
 782                 }
 783                 break;
 784         }
 785         case PPPIOCSACTIVE:
 786         {
 787                 struct sock_filter *code;
 788
 789                 err = get_filter(argp, &code);
 790                 if (err >= 0) {
 791                         struct bpf_prog *active_filter = NULL;
 792                         struct sock_fprog_kern fprog = {
 793                                 .len = err,
 794                                 .filter = code,
 795                         };
 796
 797                         err = 0;
 798                         if (fprog.filter)
 799                                 err = bpf_prog_create(&active_filter, &fprog);
 800                         if (!err) {
 801                                 ppp_lock(ppp);
 802                                 if (ppp->active_filter)
 803                                         bpf_prog_destroy(ppp->active_filter);
 804                                 ppp->active_filter = active_filter;
 805                                 ppp_unlock(ppp);
 806                         }
 807                         kfree(code);
 808                 }
 809                 break;
 810         }
 811 #endif /* CONFIG_PPP_FILTER */
 812
 813 #ifdef CONFIG_PPP_MULTILINK
 814         case PPPIOCSMRRU:
 815                 if (get_user(val, p))
 816                         break;
 817                 ppp_recv_lock(ppp);
 818                 ppp->mrru = val;
 819                 ppp_recv_unlock(ppp);
 820                 err = 0;
 821                 break;
 822 #endif /* CONFIG_PPP_MULTILINK */
 823
 824         default:
 825                 err = -ENOTTY;
 826         }
 827
 828 out:
 829         mutex_unlock(&ppp_mutex);
 830
 831         return err;
 832 }
 833
 834 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 835                         struct file *file, unsigned int cmd, unsigned long arg)
 836 {
 837         int unit, err = -EFAULT;
 838         struct ppp *ppp;
 839         struct channel *chan;
 840         struct ppp_net *pn;
 841         int __user *p = (int __user *)arg;
 842
 843         switch (cmd) {
 844         case PPPIOCNEWUNIT:
 845                 /* Create a new ppp unit */
 846                 if (get_user(unit, p))
 847                         break;
 848                 ppp = ppp_create_interface(net, unit, file, &err);
 849                 if (!ppp)
 850                         break;
 851                 file->private_data = &ppp->file;
 852                 err = -EFAULT;
 853                 if (put_user(ppp->file.index, p))
 854                         break;
 855                 err = 0;
 856                 break;
 857
 858         case PPPIOCATTACH:
 859                 /* Attach to an existing ppp unit */
 860                 if (get_user(unit, p))
 861                         break;
 862                 err = -ENXIO;
 863                 pn = ppp_pernet(net);
 864                 mutex_lock(&pn->all_ppp_mutex);
 865                 ppp = ppp_find_unit(pn, unit);
 866                 if (ppp) {
 867                         atomic_inc(&ppp->file.refcnt);
 868                         file->private_data = &ppp->file;
 869                         err = 0;
 870                 }
 871                 mutex_unlock(&pn->all_ppp_mutex);
 872                 break;
 873
 874         case PPPIOCATTCHAN:
 875                 if (get_user(unit, p))
 876                         break;
 877                 err = -ENXIO;
 878                 pn = ppp_pernet(net);
 879                 spin_lock_bh(&pn->all_channels_lock);
 880                 chan = ppp_find_channel(pn, unit);
 881                 if (chan) {
 882                         atomic_inc(&chan->file.refcnt);
 883                         file->private_data = &chan->file;
 884                         err = 0;
 885                 }
 886                 spin_unlock_bh(&pn->all_channels_lock);
 887                 break;
 888
 889         default:
 890                 err = -ENOTTY;
 891         }
 892
 893         return err;
 894 }
 895
 896 static const struct file_operations ppp_device_fops = {
 897         .owner          = THIS_MODULE,
 898         .read           = ppp_read,
 899         .write          = ppp_write,
 900         .poll           = ppp_poll,
 901         .unlocked_ioctl = ppp_ioctl,
 902         .open           = ppp_open,
 903         .release        = ppp_release,
 904         .llseek         = noop_llseek,
 905 };
 906
 907 static __net_init int ppp_init_net(struct net *net)
 908 {
 909         struct ppp_net *pn = net_generic(net, ppp_net_id);
 910
 911         idr_init(&pn->units_idr);
 912         mutex_init(&pn->all_ppp_mutex);
 913
 914         INIT_LIST_HEAD(&pn->all_channels);
 915         INIT_LIST_HEAD(&pn->new_channels);
 916
 917         spin_lock_init(&pn->all_channels_lock);
 918
 919         return 0;
 920 }
 921
 922 static __net_exit void ppp_exit_net(struct net *net)
 923 {
 924         struct ppp_net *pn = net_generic(net, ppp_net_id);
 925         struct net_device *dev;
 926         struct net_device *aux;
 927         struct ppp *ppp;
 928         LIST_HEAD(list);
 929         int id;
 930
 931         rtnl_lock();
 932         for_each_netdev_safe(net, dev, aux) {
 933                 if (dev->netdev_ops == &ppp_netdev_ops)
 934                         unregister_netdevice_queue(dev, &list);
 935         }
 936
 937         idr_for_each_entry(&pn->units_idr, ppp, id)
 938                 /* Skip devices already unregistered by previous loop */
 939                 if (!net_eq(dev_net(ppp->dev), net))
 940                         unregister_netdevice_queue(ppp->dev, &list);
 941
 942         unregister_netdevice_many(&list);
 943         rtnl_unlock();
 944
 945         idr_destroy(&pn->units_idr);
 946 }
 947
 948 static struct pernet_operations ppp_net_ops = {
 949         .init = ppp_init_net,
 950         .exit = ppp_exit_net,
 951         .id   = &ppp_net_id,
 952         .size = sizeof(struct ppp_net),
 953 };
 954
 955 #define PPP_MAJOR       108
 956
 957 /* Called at boot time if ppp is compiled into the kernel,
 958    or at module load time (from init_module) if compiled as a module. */
 959 static int __init ppp_init(void)
 960 {
 961         int err;
 962
 963         pr_info("PPP generic driver version " PPP_VERSION "\n");
 964
 965         err = register_pernet_device(&ppp_net_ops);
 966         if (err) {
 967                 pr_err("failed to register PPP pernet device (%d)\n", err);
 968                 goto out;
 969         }
 970
 971         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 972         if (err) {
 973                 pr_err("failed to register PPP device (%d)\n", err);
 974                 goto out_net;
 975         }
 976
 977         ppp_class = class_create(THIS_MODULE, "ppp");
 978         if (IS_ERR(ppp_class)) {
 979                 err = PTR_ERR(ppp_class);
 980                 goto out_chrdev;
 981         }
 982
 983         /* not a big deal if we fail here :-) */
 984         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 985
 986         return 0;
 987
 988 out_chrdev:
 989         unregister_chrdev(PPP_MAJOR, "ppp");
 990 out_net:
 991         unregister_pernet_device(&ppp_net_ops);
 992 out:
 993         return err;
 994 }
 995
 996 /*
 997  * Network interface unit routines.
 998  */
 999 static netdev_tx_t
1000 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1001 {
1002         struct ppp *ppp = netdev_priv(dev);
1003         int npi, proto;
1004         unsigned char *pp;
1005
1006         npi = ethertype_to_npindex(ntohs(skb->protocol));
1007         if (npi < 0)
1008                 goto outf;
1009
1010         /* Drop, accept or reject the packet */
1011         switch (ppp->npmode[npi]) {
1012         case NPMODE_PASS:
1013                 break;
1014         case NPMODE_QUEUE:
1015                 /* it would be nice to have a way to tell the network
1016                    system to queue this one up for later. */
1017                 goto outf;
1018         case NPMODE_DROP:
1019         case NPMODE_ERROR:
1020                 goto outf;
1021         }
1022
1023         /* Put the 2-byte PPP protocol number on the front,
1024            making sure there is room for the address and control fields. */
1025         if (skb_cow_head(skb, PPP_HDRLEN))
1026                 goto outf;
1027
1028         pp = skb_push(skb, 2);
1029         proto = npindex_to_proto[npi];
1030         put_unaligned_be16(proto, pp);
1031
1032         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1033         skb_queue_tail(&ppp->file.xq, skb);
1034         ppp_xmit_process(ppp);
1035         return NETDEV_TX_OK;
1036
1037  outf:
1038         kfree_skb(skb);
1039         ++dev->stats.tx_dropped;
1040         return NETDEV_TX_OK;
1041 }
1042
1043 static int
1044 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1045 {
1046         struct ppp *ppp = netdev_priv(dev);
1047         int err = -EFAULT;
1048         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1049         struct ppp_stats stats;
1050         struct ppp_comp_stats cstats;
1051         char *vers;
1052
1053         switch (cmd) {
1054         case SIOCGPPPSTATS:
1055                 ppp_get_stats(ppp, &stats);
1056                 if (copy_to_user(addr, &stats, sizeof(stats)))
1057                         break;
1058                 err = 0;
1059                 break;
1060
1061         case SIOCGPPPCSTATS:
1062                 memset(&cstats, 0, sizeof(cstats));
1063                 if (ppp->xc_state)
1064                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1065                 if (ppp->rc_state)
1066                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1067                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1068                         break;
1069                 err = 0;
1070                 break;
1071
1072         case SIOCGPPPVER:
1073                 vers = PPP_VERSION;
1074                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1075                         break;
1076                 err = 0;
1077                 break;
1078
1079         default:
1080                 err = -EINVAL;
1081         }
1082
1083         return err;
1084 }
1085
1086 static struct rtnl_link_stats64*
1087 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1088 {
1089         struct ppp *ppp = netdev_priv(dev);
1090
1091         ppp_recv_lock(ppp);
1092         stats64->rx_packets = ppp->stats64.rx_packets;
1093         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1094         ppp_recv_unlock(ppp);
1095
1096         ppp_xmit_lock(ppp);
1097         stats64->tx_packets = ppp->stats64.tx_packets;
1098         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1099         ppp_xmit_unlock(ppp);
1100
1101         stats64->rx_errors        = dev->stats.rx_errors;
1102         stats64->tx_errors        = dev->stats.tx_errors;
1103         stats64->rx_dropped       = dev->stats.rx_dropped;
1104         stats64->tx_dropped       = dev->stats.tx_dropped;
1105         stats64->rx_length_errors = dev->stats.rx_length_errors;
1106
1107         return stats64;
1108 }
1109
1110 static struct lock_class_key ppp_tx_busylock;
1111 static int ppp_dev_init(struct net_device *dev)
1112 {
1113         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1114         return 0;
1115 }
1116
1117 static void ppp_dev_uninit(struct net_device *dev)
1118 {
1119         struct ppp *ppp = netdev_priv(dev);
1120         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1121
1122         ppp_lock(ppp);
1123         ppp->closing = 1;
1124         ppp_unlock(ppp);
1125
1126         mutex_lock(&pn->all_ppp_mutex);
1127         unit_put(&pn->units_idr, ppp->file.index);
1128         mutex_unlock(&pn->all_ppp_mutex);
1129
1130         ppp->owner = NULL;
1131
1132         ppp->file.dead = 1;
1133         wake_up_interruptible(&ppp->file.rwait);
1134 }
1135
1136 static const struct net_device_ops ppp_netdev_ops = {
1137         .ndo_init        = ppp_dev_init,
1138         .ndo_uninit      = ppp_dev_uninit,
1139         .ndo_start_xmit  = ppp_start_xmit,
1140         .ndo_do_ioctl    = ppp_net_ioctl,
1141         .ndo_get_stats64 = ppp_get_stats64,
1142 };
1143
1144 static void ppp_setup(struct net_device *dev)
1145 {
1146         dev->netdev_ops = &ppp_netdev_ops;
1147         dev->hard_header_len = PPP_HDRLEN;
1148         dev->mtu = PPP_MRU;
1149         dev->addr_len = 0;
1150         dev->tx_queue_len = 3;
1151         dev->type = ARPHRD_PPP;
1152         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1153         netif_keep_dst(dev);
1154 }
1155
1156 /*
1157  * Transmit-side routines.
1158  */
1159
1160 /*
1161  * Called to do any work queued up on the transmit side
1162  * that can now be done.
1163  */
1164 static void
1165 ppp_xmit_process(struct ppp *ppp)
1166 {
1167         struct sk_buff *skb;
1168
1169         ppp_xmit_lock(ppp);
1170         if (!ppp->closing) {
1171                 ppp_push(ppp);
1172                 while (!ppp->xmit_pending &&
1173                        (skb = skb_dequeue(&ppp->file.xq)))
1174                         ppp_send_frame(ppp, skb);
1175                 /* If there's no work left to do, tell the core net
1176                    code that we can accept some more. */
1177                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1178                         netif_wake_queue(ppp->dev);
1179                 else
1180                         netif_stop_queue(ppp->dev);
1181         }
1182         ppp_xmit_unlock(ppp);
1183 }
1184
1185 static inline struct sk_buff *
1186 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1187 {
1188         struct sk_buff *new_skb;
1189         int len;
1190         int new_skb_size = ppp->dev->mtu +
1191                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1192         int compressor_skb_size = ppp->dev->mtu +
1193                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1194         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1195         if (!new_skb) {
1196                 if (net_ratelimit())
1197                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1198                 return NULL;
1199         }
1200         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1201                 skb_reserve(new_skb,
1202                             ppp->dev->hard_header_len - PPP_HDRLEN);
1203
1204         /* compressor still expects A/C bytes in hdr */
1205         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1206                                    new_skb->data, skb->len + 2,
1207                                    compressor_skb_size);
1208         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1209                 consume_skb(skb);
1210                 skb = new_skb;
1211                 skb_put(skb, len);
1212                 skb_pull(skb, 2);       /* pull off A/C bytes */
1213         } else if (len == 0) {
1214                 /* didn't compress, or CCP not up yet */
1215                 consume_skb(new_skb);
1216                 new_skb = skb;
1217         } else {
1218                 /*
1219                  * (len < 0)
1220                  * MPPE requires that we do not send unencrypted
1221                  * frames.  The compressor will return -1 if we
1222                  * should drop the frame.  We cannot simply test
1223                  * the compress_proto because MPPE and MPPC share
1224                  * the same number.
1225                  */
1226                 if (net_ratelimit())
1227                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1228                 kfree_skb(skb);
1229                 consume_skb(new_skb);
1230                 new_skb = NULL;
1231         }
1232         return new_skb;
1233 }
1234
1235 /*
1236  * Compress and send a frame.
1237  * The caller should have locked the xmit path,
1238  * and xmit_pending should be 0.
1239  */
1240 static void
1241 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1242 {
1243         int proto = PPP_PROTO(skb);
1244         struct sk_buff *new_skb;
1245         int len;
1246         unsigned char *cp;
1247
1248         if (proto < 0x8000) {
1249 #ifdef CONFIG_PPP_FILTER
1250                 /* check if we should pass this packet */
1251                 /* the filter instructions are constructed assuming
1252                    a four-byte PPP header on each packet */
1253                 *skb_push(skb, 2) = 1;
1254                 if (ppp->pass_filter &&
1255                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1256                         if (ppp->debug & 1)
1257                                 netdev_printk(KERN_DEBUG, ppp->dev,
1258                                               "PPP: outbound frame "
1259                                               "not passed\n");
1260                         kfree_skb(skb);
1261                         return;
1262                 }
1263                 /* if this packet passes the active filter, record the time */
1264                 if (!(ppp->active_filter &&
1265                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1266                         ppp->last_xmit = jiffies;
1267                 skb_pull(skb, 2);
1268 #else
1269                 /* for data packets, record the time */
1270                 ppp->last_xmit = jiffies;
1271 #endif /* CONFIG_PPP_FILTER */
1272         }
1273
1274         ++ppp->stats64.tx_packets;
1275         ppp->stats64.tx_bytes += skb->len - 2;
1276
1277         switch (proto) {
1278         case PPP_IP:
1279                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1280                         break;
1281                 /* try to do VJ TCP header compression */
1282                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1283                                     GFP_ATOMIC);
1284                 if (!new_skb) {
1285                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1286                         goto drop;
1287                 }
1288                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1289                 cp = skb->data + 2;
1290                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1291                                     new_skb->data + 2, &cp,
1292                                     !(ppp->flags & SC_NO_TCP_CCID));
1293                 if (cp == skb->data + 2) {
1294                         /* didn't compress */
1295                         consume_skb(new_skb);
1296                 } else {
1297                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1298                                 proto = PPP_VJC_COMP;
1299                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1300                         } else {
1301                                 proto = PPP_VJC_UNCOMP;
1302                                 cp[0] = skb->data[2];
1303                         }
1304                         consume_skb(skb);
1305                         skb = new_skb;
1306                         cp = skb_put(skb, len + 2);
1307                         cp[0] = 0;
1308                         cp[1] = proto;
1309                 }
1310                 break;
1311
1312         case PPP_CCP:
1313                 /* peek at outbound CCP frames */
1314                 ppp_ccp_peek(ppp, skb, 0);
1315                 break;
1316         }
1317
1318         /* try to do packet compression */
1319         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1320             proto != PPP_LCP && proto != PPP_CCP) {
1321                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1322                         if (net_ratelimit())
1323                                 netdev_err(ppp->dev,
1324                                            "ppp: compression required but "
1325                                            "down - pkt dropped.\n");
1326                         goto drop;
1327                 }
1328                 skb = pad_compress_skb(ppp, skb);
1329                 if (!skb)
1330                         goto drop;
1331         }
1332
1333         /*
1334          * If we are waiting for traffic (demand dialling),
1335          * queue it up for pppd to receive.
1336          */
1337         if (ppp->flags & SC_LOOP_TRAFFIC) {
1338                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1339                         goto drop;
1340                 skb_queue_tail(&ppp->file.rq, skb);
1341                 wake_up_interruptible(&ppp->file.rwait);
1342                 return;
1343         }
1344
1345         ppp->xmit_pending = skb;
1346         ppp_push(ppp);
1347         return;
1348
1349  drop:
1350         kfree_skb(skb);
1351         ++ppp->dev->stats.tx_errors;
1352 }
1353
1354 /*
1355  * Try to send the frame in xmit_pending.
1356  * The caller should have the xmit path locked.
1357  */
1358 static void
1359 ppp_push(struct ppp *ppp)
1360 {
1361         struct list_head *list;
1362         struct channel *pch;
1363         struct sk_buff *skb = ppp->xmit_pending;
1364
1365         if (!skb)
1366                 return;
1367
1368         list = &ppp->channels;
1369         if (list_empty(list)) {
1370                 /* nowhere to send the packet, just drop it */
1371                 ppp->xmit_pending = NULL;
1372                 kfree_skb(skb);
1373                 return;
1374         }
1375
1376         if ((ppp->flags & SC_MULTILINK) == 0) {
1377                 /* not doing multilink: send it down the first channel */
1378                 list = list->next;
1379                 pch = list_entry(list, struct channel, clist);
1380
1381                 spin_lock_bh(&pch->downl);
1382                 if (pch->chan) {
1383                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1384                                 ppp->xmit_pending = NULL;
1385                 } else {
1386                         /* channel got unregistered */
1387                         kfree_skb(skb);
1388                         ppp->xmit_pending = NULL;
1389                 }
1390                 spin_unlock_bh(&pch->downl);
1391                 return;
1392         }
1393
1394 #ifdef CONFIG_PPP_MULTILINK
1395         /* Multilink: fragment the packet over as many links
1396            as can take the packet at the moment. */
1397         if (!ppp_mp_explode(ppp, skb))
1398                 return;
1399 #endif /* CONFIG_PPP_MULTILINK */
1400
1401         ppp->xmit_pending = NULL;
1402         kfree_skb(skb);
1403 }
1404
1405 #ifdef CONFIG_PPP_MULTILINK
1406 static bool mp_protocol_compress __read_mostly = true;
1407 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1408 MODULE_PARM_DESC(mp_protocol_compress,
1409                  "compress protocol id in multilink fragments");
1410
1411 /*
1412  * Divide a packet to be transmitted into fragments and
1413  * send them out the individual links.
1414  */
1415 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1416 {
1417         int len, totlen;
1418         int i, bits, hdrlen, mtu;
1419         int flen;
1420         int navail, nfree, nzero;
1421         int nbigger;
1422         int totspeed;
1423         int totfree;
1424         unsigned char *p, *q;
1425         struct list_head *list;
1426         struct channel *pch;
1427         struct sk_buff *frag;
1428         struct ppp_channel *chan;
1429
1430         totspeed = 0; /*total bitrate of the bundle*/
1431         nfree = 0; /* # channels which have no packet already queued */
1432         navail = 0; /* total # of usable channels (not deregistered) */
1433         nzero = 0; /* number of channels with zero speed associated*/
1434         totfree = 0; /*total # of channels available and
1435                                   *having no queued packets before
1436                                   *starting the fragmentation*/
1437
1438         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1439         i = 0;
1440         list_for_each_entry(pch, &ppp->channels, clist) {
1441                 if (pch->chan) {
1442                         pch->avail = 1;
1443                         navail++;
1444                         pch->speed = pch->chan->speed;
1445                 } else {
1446                         pch->avail = 0;
1447                 }
1448                 if (pch->avail) {
1449                         if (skb_queue_empty(&pch->file.xq) ||
1450                                 !pch->had_frag) {
1451                                         if (pch->speed == 0)
1452                                                 nzero++;
1453                                         else
1454                                                 totspeed += pch->speed;
1455
1456                                         pch->avail = 2;
1457                                         ++nfree;
1458                                         ++totfree;
1459                                 }
1460                         if (!pch->had_frag && i < ppp->nxchan)
1461                                 ppp->nxchan = i;
1462                 }
1463                 ++i;
1464         }
1465         /*
1466          * Don't start sending this packet unless at least half of
1467          * the channels are free.  This gives much better TCP
1468          * performance if we have a lot of channels.
1469          */
1470         if (nfree == 0 || nfree < navail / 2)
1471                 return 0; /* can't take now, leave it in xmit_pending */
1472
1473         /* Do protocol field compression */
1474         p = skb->data;
1475         len = skb->len;
1476         if (*p == 0 && mp_protocol_compress) {
1477                 ++p;
1478                 --len;
1479         }
1480
1481         totlen = len;
1482         nbigger = len % nfree;
1483
1484         /* skip to the channel after the one we last used
1485            and start at that one */
1486         list = &ppp->channels;
1487         for (i = 0; i < ppp->nxchan; ++i) {
1488                 list = list->next;
1489                 if (list == &ppp->channels) {
1490                         i = 0;
1491                         break;
1492                 }
1493         }
1494
1495         /* create a fragment for each channel */
1496         bits = B;
1497         while (len > 0) {
1498                 list = list->next;
1499                 if (list == &ppp->channels) {
1500                         i = 0;
1501                         continue;
1502                 }
1503                 pch = list_entry(list, struct channel, clist);
1504                 ++i;
1505                 if (!pch->avail)
1506                         continue;
1507
1508                 /*
1509                  * Skip this channel if it has a fragment pending already and
1510                  * we haven't given a fragment to all of the free channels.
1511                  */
1512                 if (pch->avail == 1) {
1513                         if (nfree > 0)
1514                                 continue;
1515                 } else {
1516                         pch->avail = 1;
1517                 }
1518
1519                 /* check the channel's mtu and whether it is still attached. */
1520                 spin_lock_bh(&pch->downl);
1521                 if (pch->chan == NULL) {
1522                         /* can't use this channel, it's being deregistered */
1523                         if (pch->speed == 0)
1524                                 nzero--;
1525                         else
1526                                 totspeed -= pch->speed;
1527
1528                         spin_unlock_bh(&pch->downl);
1529                         pch->avail = 0;
1530                         totlen = len;
1531                         totfree--;
1532                         nfree--;
1533                         if (--navail == 0)
1534                                 break;
1535                         continue;
1536                 }
1537
1538                 /*
1539                 *if the channel speed is not set divide
1540                 *the packet evenly among the free channels;
1541                 *otherwise divide it according to the speed
1542                 *of the channel we are going to transmit on
1543                 */
1544                 flen = len;
1545                 if (nfree > 0) {
1546                         if (pch->speed == 0) {
1547                                 flen = len/nfree;
1548                                 if (nbigger > 0) {
1549                                         flen++;
1550                                         nbigger--;
1551                                 }
1552                         } else {
1553                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1554                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1555                                 if (nbigger > 0) {
1556                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1557                                         nbigger -= ((totfree - nzero)*pch->speed)/
1558                                                         totspeed;
1559                                 }
1560                         }
1561                         nfree--;
1562                 }
1563
1564                 /*
1565                  *check if we are on the last channel or
1566                  *we exceded the length of the data to
1567                  *fragment
1568                  */
1569                 if ((nfree <= 0) || (flen > len))
1570                         flen = len;
1571                 /*
1572                  *it is not worth to tx on slow channels:
1573                  *in that case from the resulting flen according to the
1574                  *above formula will be equal or less than zero.
1575                  *Skip the channel in this case
1576                  */
1577                 if (flen <= 0) {
1578                         pch->avail = 2;
1579                         spin_unlock_bh(&pch->downl);
1580                         continue;
1581                 }
1582
1583                 /*
1584                  * hdrlen includes the 2-byte PPP protocol field, but the
1585                  * MTU counts only the payload excluding the protocol field.
1586                  * (RFC1661 Section 2)
1587                  */
1588                 mtu = pch->chan->mtu - (hdrlen - 2);
1589                 if (mtu < 4)
1590                         mtu = 4;
1591                 if (flen > mtu)
1592                         flen = mtu;
1593                 if (flen == len)
1594                         bits |= E;
1595                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1596                 if (!frag)
1597                         goto noskb;
1598                 q = skb_put(frag, flen + hdrlen);
1599
1600                 /* make the MP header */
1601                 put_unaligned_be16(PPP_MP, q);
1602                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1603                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1604                         q[3] = ppp->nxseq;
1605                 } else {
1606                         q[2] = bits;
1607                         q[3] = ppp->nxseq >> 16;
1608                         q[4] = ppp->nxseq >> 8;
1609                         q[5] = ppp->nxseq;
1610                 }
1611
1612                 memcpy(q + hdrlen, p, flen);
1613
1614                 /* try to send it down the channel */
1615                 chan = pch->chan;
1616                 if (!skb_queue_empty(&pch->file.xq) ||
1617                         !chan->ops->start_xmit(chan, frag))
1618                         skb_queue_tail(&pch->file.xq, frag);
1619                 pch->had_frag = 1;
1620                 p += flen;
1621                 len -= flen;
1622                 ++ppp->nxseq;
1623                 bits = 0;
1624                 spin_unlock_bh(&pch->downl);
1625         }
1626         ppp->nxchan = i;
1627
1628         return 1;
1629
1630  noskb:
1631         spin_unlock_bh(&pch->downl);
1632         if (ppp->debug & 1)
1633                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1634         ++ppp->dev->stats.tx_errors;
1635         ++ppp->nxseq;
1636         return 1;       /* abandon the frame */
1637 }
1638 #endif /* CONFIG_PPP_MULTILINK */
1639
1640 /*
1641  * Try to send data out on a channel.
1642  */
1643 static void
1644 ppp_channel_push(struct channel *pch)
1645 {
1646         struct sk_buff *skb;
1647         struct ppp *ppp;
1648
1649         spin_lock_bh(&pch->downl);
1650         if (pch->chan) {
1651                 while (!skb_queue_empty(&pch->file.xq)) {
1652                         skb = skb_dequeue(&pch->file.xq);
1653                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1654                                 /* put the packet back and try again later */
1655                                 skb_queue_head(&pch->file.xq, skb);
1656                                 break;
1657                         }
1658                 }
1659         } else {
1660                 /* channel got deregistered */
1661                 skb_queue_purge(&pch->file.xq);
1662         }
1663         spin_unlock_bh(&pch->downl);
1664         /* see if there is anything from the attached unit to be sent */
1665         if (skb_queue_empty(&pch->file.xq)) {
1666                 read_lock_bh(&pch->upl);
1667                 ppp = pch->ppp;
1668                 if (ppp)
1669                         ppp_xmit_process(ppp);
1670                 read_unlock_bh(&pch->upl);
1671         }
1672 }
1673
1674 /*
1675  * Receive-side routines.
1676  */
1677
1678 struct ppp_mp_skb_parm {
1679         u32             sequence;
1680         u8              BEbits;
1681 };
1682 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1683
1684 static inline void
1685 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1686 {
1687         ppp_recv_lock(ppp);
1688         if (!ppp->closing)
1689                 ppp_receive_frame(ppp, skb, pch);
1690         else
1691                 kfree_skb(skb);
1692         ppp_recv_unlock(ppp);
1693 }
1694
1695 void
1696 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1697 {
1698         struct channel *pch = chan->ppp;
1699         int proto;
1700
1701         if (!pch) {
1702                 kfree_skb(skb);
1703                 return;
1704         }
1705
1706         read_lock_bh(&pch->upl);
1707         if (!pskb_may_pull(skb, 2)) {
1708                 kfree_skb(skb);
1709                 if (pch->ppp) {
1710                         ++pch->ppp->dev->stats.rx_length_errors;
1711                         ppp_receive_error(pch->ppp);
1712                 }
1713                 goto done;
1714         }
1715
1716         proto = PPP_PROTO(skb);
1717         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1718                 /* put it on the channel queue */
1719                 skb_queue_tail(&pch->file.rq, skb);
1720                 /* drop old frames if queue too long */
1721                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1722                        (skb = skb_dequeue(&pch->file.rq)))
1723                         kfree_skb(skb);
1724                 wake_up_interruptible(&pch->file.rwait);
1725         } else {
1726                 ppp_do_recv(pch->ppp, skb, pch);
1727         }
1728
1729 done:
1730         read_unlock_bh(&pch->upl);
1731 }
1732
1733 /* Put a 0-length skb in the receive queue as an error indication */
1734 void
1735 ppp_input_error(struct ppp_channel *chan, int code)
1736 {
1737         struct channel *pch = chan->ppp;
1738         struct sk_buff *skb;
1739
1740         if (!pch)
1741                 return;
1742
1743         read_lock_bh(&pch->upl);
1744         if (pch->ppp) {
1745                 skb = alloc_skb(0, GFP_ATOMIC);
1746                 if (skb) {
1747                         skb->len = 0;           /* probably unnecessary */
1748                         skb->cb[0] = code;
1749                         ppp_do_recv(pch->ppp, skb, pch);
1750                 }
1751         }
1752         read_unlock_bh(&pch->upl);
1753 }
1754
1755 /*
1756  * We come in here to process a received frame.
1757  * The receive side of the ppp unit is locked.
1758  */
1759 static void
1760 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1761 {
1762         /* note: a 0-length skb is used as an error indication */
1763         if (skb->len > 0) {
1764                 skb_checksum_complete_unset(skb);
1765 #ifdef CONFIG_PPP_MULTILINK
1766                 /* XXX do channel-level decompression here */
1767                 if (PPP_PROTO(skb) == PPP_MP)
1768                         ppp_receive_mp_frame(ppp, skb, pch);
1769                 else
1770 #endif /* CONFIG_PPP_MULTILINK */
1771                         ppp_receive_nonmp_frame(ppp, skb);
1772         } else {
1773                 kfree_skb(skb);
1774                 ppp_receive_error(ppp);
1775         }
1776 }
1777
1778 static void
1779 ppp_receive_error(struct ppp *ppp)
1780 {
1781         ++ppp->dev->stats.rx_errors;
1782         if (ppp->vj)
1783                 slhc_toss(ppp->vj);
1784 }
1785
1786 static void
1787 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1788 {
1789         struct sk_buff *ns;
1790         int proto, len, npi;
1791
1792         /*
1793          * Decompress the frame, if compressed.
1794          * Note that some decompressors need to see uncompressed frames
1795          * that come in as well as compressed frames.
1796          */
1797         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1798             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1799                 skb = ppp_decompress_frame(ppp, skb);
1800
1801         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1802                 goto err;
1803
1804         proto = PPP_PROTO(skb);
1805         switch (proto) {
1806         case PPP_VJC_COMP:
1807                 /* decompress VJ compressed packets */
1808                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1809                         goto err;
1810
1811                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1812                         /* copy to a new sk_buff with more tailroom */
1813                         ns = dev_alloc_skb(skb->len + 128);
1814                         if (!ns) {
1815                                 netdev_err(ppp->dev, "PPP: no memory "
1816                                            "(VJ decomp)\n");
1817                                 goto err;
1818                         }
1819                         skb_reserve(ns, 2);
1820                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1821                         consume_skb(skb);
1822                         skb = ns;
1823                 }
1824                 else
1825                         skb->ip_summed = CHECKSUM_NONE;
1826
1827                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1828                 if (len <= 0) {
1829                         netdev_printk(KERN_DEBUG, ppp->dev,
1830                                       "PPP: VJ decompression error\n");
1831                         goto err;
1832                 }
1833                 len += 2;
1834                 if (len > skb->len)
1835                         skb_put(skb, len - skb->len);
1836                 else if (len < skb->len)
1837                         skb_trim(skb, len);
1838                 proto = PPP_IP;
1839                 break;
1840
1841         case PPP_VJC_UNCOMP:
1842                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1843                         goto err;
1844
1845                 /* Until we fix the decompressor need to make sure
1846                  * data portion is linear.
1847                  */
1848                 if (!pskb_may_pull(skb, skb->len))
1849                         goto err;
1850
1851                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1852                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1853                         goto err;
1854                 }
1855                 proto = PPP_IP;
1856                 break;
1857
1858         case PPP_CCP:
1859                 ppp_ccp_peek(ppp, skb, 1);
1860                 break;
1861         }
1862
1863         ++ppp->stats64.rx_packets;
1864         ppp->stats64.rx_bytes += skb->len - 2;
1865
1866         npi = proto_to_npindex(proto);
1867         if (npi < 0) {
1868                 /* control or unknown frame - pass it to pppd */
1869                 skb_queue_tail(&ppp->file.rq, skb);
1870                 /* limit queue length by dropping old frames */
1871                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1872                        (skb = skb_dequeue(&ppp->file.rq)))
1873                         kfree_skb(skb);
1874                 /* wake up any process polling or blocking on read */
1875                 wake_up_interruptible(&ppp->file.rwait);
1876
1877         } else {
1878                 /* network protocol frame - give it to the kernel */
1879
1880 #ifdef CONFIG_PPP_FILTER
1881                 /* check if the packet passes the pass and active filters */
1882                 /* the filter instructions are constructed assuming
1883                    a four-byte PPP header on each packet */
1884                 if (ppp->pass_filter || ppp->active_filter) {
1885                         if (skb_unclone(skb, GFP_ATOMIC))
1886                                 goto err;
1887
1888                         *skb_push(skb, 2) = 0;
1889                         if (ppp->pass_filter &&
1890                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1891                                 if (ppp->debug & 1)
1892                                         netdev_printk(KERN_DEBUG, ppp->dev,
1893                                                       "PPP: inbound frame "
1894                                                       "not passed\n");
1895                                 kfree_skb(skb);
1896                                 return;
1897                         }
1898                         if (!(ppp->active_filter &&
1899                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1900                                 ppp->last_recv = jiffies;
1901                         __skb_pull(skb, 2);
1902                 } else
1903 #endif /* CONFIG_PPP_FILTER */
1904                         ppp->last_recv = jiffies;
1905
1906                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1907                     ppp->npmode[npi] != NPMODE_PASS) {
1908                         kfree_skb(skb);
1909                 } else {
1910                         /* chop off protocol */
1911                         skb_pull_rcsum(skb, 2);
1912                         skb->dev = ppp->dev;
1913                         skb->protocol = htons(npindex_to_ethertype[npi]);
1914                         skb_reset_mac_header(skb);
1915                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
1916                                                       dev_net(ppp->dev)));
1917                         netif_rx(skb);
1918                 }
1919         }
1920         return;
1921
1922  err:
1923         kfree_skb(skb);
1924         ppp_receive_error(ppp);
1925 }
1926
1927 static struct sk_buff *
1928 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1929 {
1930         int proto = PPP_PROTO(skb);
1931         struct sk_buff *ns;
1932         int len;
1933
1934         /* Until we fix all the decompressor's need to make sure
1935          * data portion is linear.
1936          */
1937         if (!pskb_may_pull(skb, skb->len))
1938                 goto err;
1939
1940         if (proto == PPP_COMP) {
1941                 int obuff_size;
1942
1943                 switch(ppp->rcomp->compress_proto) {
1944                 case CI_MPPE:
1945                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1946                         break;
1947                 default:
1948                         obuff_size = ppp->mru + PPP_HDRLEN;
1949                         break;
1950                 }
1951
1952                 ns = dev_alloc_skb(obuff_size);
1953                 if (!ns) {
1954                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1955                                    "no memory\n");
1956                         goto err;
1957                 }
1958                 /* the decompressor still expects the A/C bytes in the hdr */
1959                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1960                                 skb->len + 2, ns->data, obuff_size);
1961                 if (len < 0) {
1962                         /* Pass the compressed frame to pppd as an
1963                            error indication. */
1964                         if (len == DECOMP_FATALERROR)
1965                                 ppp->rstate |= SC_DC_FERROR;
1966                         kfree_skb(ns);
1967                         goto err;
1968                 }
1969
1970                 consume_skb(skb);
1971                 skb = ns;
1972                 skb_put(skb, len);
1973                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1974
1975         } else {
1976                 /* Uncompressed frame - pass to decompressor so it
1977                    can update its dictionary if necessary. */
1978                 if (ppp->rcomp->incomp)
1979                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1980                                            skb->len + 2);
1981         }
1982
1983         return skb;
1984
1985  err:
1986         ppp->rstate |= SC_DC_ERROR;
1987         ppp_receive_error(ppp);
1988         return skb;
1989 }
1990
1991 #ifdef CONFIG_PPP_MULTILINK
1992 /*
1993  * Receive a multilink frame.
1994  * We put it on the reconstruction queue and then pull off
1995  * as many completed frames as we can.
1996  */
1997 static void
1998 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1999 {
2000         u32 mask, seq;
2001         struct channel *ch;
2002         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2003
2004         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2005                 goto err;               /* no good, throw it away */
2006
2007         /* Decode sequence number and begin/end bits */
2008         if (ppp->flags & SC_MP_SHORTSEQ) {
2009                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2010                 mask = 0xfff;
2011         } else {
2012                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2013                 mask = 0xffffff;
2014         }
2015         PPP_MP_CB(skb)->BEbits = skb->data[2];
2016         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2017
2018         /*
2019          * Do protocol ID decompression on the first fragment of each packet.
2020          */
2021         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2022                 *skb_push(skb, 1) = 0;
2023
2024         /*
2025          * Expand sequence number to 32 bits, making it as close
2026          * as possible to ppp->minseq.
2027          */
2028         seq |= ppp->minseq & ~mask;
2029         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2030                 seq += mask + 1;
2031         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2032                 seq -= mask + 1;        /* should never happen */
2033         PPP_MP_CB(skb)->sequence = seq;
2034         pch->lastseq = seq;
2035
2036         /*
2037          * If this packet comes before the next one we were expecting,
2038          * drop it.
2039          */
2040         if (seq_before(seq, ppp->nextseq)) {
2041                 kfree_skb(skb);
2042                 ++ppp->dev->stats.rx_dropped;
2043                 ppp_receive_error(ppp);
2044                 return;
2045         }
2046
2047         /*
2048          * Reevaluate minseq, the minimum over all channels of the
2049          * last sequence number received on each channel.  Because of
2050          * the increasing sequence number rule, we know that any fragment
2051          * before `minseq' which hasn't arrived is never going to arrive.
2052          * The list of channels can't change because we have the receive
2053          * side of the ppp unit locked.
2054          */
2055         list_for_each_entry(ch, &ppp->channels, clist) {
2056                 if (seq_before(ch->lastseq, seq))
2057                         seq = ch->lastseq;
2058         }
2059         if (seq_before(ppp->minseq, seq))
2060                 ppp->minseq = seq;
2061
2062         /* Put the fragment on the reconstruction queue */
2063         ppp_mp_insert(ppp, skb);
2064
2065         /* If the queue is getting long, don't wait any longer for packets
2066            before the start of the queue. */
2067         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2068                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2069                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2070                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2071         }
2072
2073         /* Pull completed packets off the queue and receive them. */
2074         while ((skb = ppp_mp_reconstruct(ppp))) {
2075                 if (pskb_may_pull(skb, 2))
2076                         ppp_receive_nonmp_frame(ppp, skb);
2077                 else {
2078                         ++ppp->dev->stats.rx_length_errors;
2079                         kfree_skb(skb);
2080                         ppp_receive_error(ppp);
2081                 }
2082         }
2083
2084         return;
2085
2086  err:
2087         kfree_skb(skb);
2088         ppp_receive_error(ppp);
2089 }
2090
2091 /*
2092  * Insert a fragment on the MP reconstruction queue.
2093  * The queue is ordered by increasing sequence number.
2094  */
2095 static void
2096 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2097 {
2098         struct sk_buff *p;
2099         struct sk_buff_head *list = &ppp->mrq;
2100         u32 seq = PPP_MP_CB(skb)->sequence;
2101
2102         /* N.B. we don't need to lock the list lock because we have the
2103            ppp unit receive-side lock. */
2104         skb_queue_walk(list, p) {
2105                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2106                         break;
2107         }
2108         __skb_queue_before(list, p, skb);
2109 }
2110
2111 /*
2112  * Reconstruct a packet from the MP fragment queue.
2113  * We go through increasing sequence numbers until we find a
2114  * complete packet, or we get to the sequence number for a fragment
2115  * which hasn't arrived but might still do so.
2116  */
2117 static struct sk_buff *
2118 ppp_mp_reconstruct(struct ppp *ppp)
2119 {
2120         u32 seq = ppp->nextseq;
2121         u32 minseq = ppp->minseq;
2122         struct sk_buff_head *list = &ppp->mrq;
2123         struct sk_buff *p, *tmp;
2124         struct sk_buff *head, *tail;
2125         struct sk_buff *skb = NULL;
2126         int lost = 0, len = 0;
2127
2128         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2129                 return NULL;
2130         head = list->next;
2131         tail = NULL;
2132         skb_queue_walk_safe(list, p, tmp) {
2133         again:
2134                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2135                         /* this can't happen, anyway ignore the skb */
2136                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2137                                    "seq %u < %u\n",
2138                                    PPP_MP_CB(p)->sequence, seq);
2139                         __skb_unlink(p, list);
2140                         kfree_skb(p);
2141                         continue;
2142                 }
2143                 if (PPP_MP_CB(p)->sequence != seq) {
2144                         u32 oldseq;
2145                         /* Fragment `seq' is missing.  If it is after
2146                            minseq, it might arrive later, so stop here. */
2147                         if (seq_after(seq, minseq))
2148                                 break;
2149                         /* Fragment `seq' is lost, keep going. */
2150                         lost = 1;
2151                         oldseq = seq;
2152                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2153                                 minseq + 1: PPP_MP_CB(p)->sequence;
2154
2155                         if (ppp->debug & 1)
2156                                 netdev_printk(KERN_DEBUG, ppp->dev,
2157                                               "lost frag %u..%u\n",
2158                                               oldseq, seq-1);
2159
2160                         goto again;
2161                 }
2162
2163                 /*
2164                  * At this point we know that all the fragments from
2165                  * ppp->nextseq to seq are either present or lost.
2166                  * Also, there are no complete packets in the queue
2167                  * that have no missing fragments and end before this
2168                  * fragment.
2169                  */
2170
2171                 /* B bit set indicates this fragment starts a packet */
2172                 if (PPP_MP_CB(p)->BEbits & B) {
2173                         head = p;
2174                         lost = 0;
2175                         len = 0;
2176                 }
2177
2178                 len += p->len;
2179
2180                 /* Got a complete packet yet? */
2181                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2182                     (PPP_MP_CB(head)->BEbits & B)) {
2183                         if (len > ppp->mrru + 2) {
2184                                 ++ppp->dev->stats.rx_length_errors;
2185                                 netdev_printk(KERN_DEBUG, ppp->dev,
2186                                               "PPP: reconstructed packet"
2187                                               " is too long (%d)\n", len);
2188                         } else {
2189                                 tail = p;
2190                                 break;
2191                         }
2192                         ppp->nextseq = seq + 1;
2193                 }
2194
2195                 /*
2196                  * If this is the ending fragment of a packet,
2197                  * and we haven't found a complete valid packet yet,
2198                  * we can discard up to and including this fragment.
2199                  */
2200                 if (PPP_MP_CB(p)->BEbits & E) {
2201                         struct sk_buff *tmp2;
2202
2203                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2204                                 if (ppp->debug & 1)
2205                                         netdev_printk(KERN_DEBUG, ppp->dev,
2206                                                       "discarding frag %u\n",
2207                                                       PPP_MP_CB(p)->sequence);
2208                                 __skb_unlink(p, list);
2209                                 kfree_skb(p);
2210                         }
2211                         head = skb_peek(list);
2212                         if (!head)
2213                                 break;
2214                 }
2215                 ++seq;
2216         }
2217
2218         /* If we have a complete packet, copy it all into one skb. */
2219         if (tail != NULL) {
2220                 /* If we have discarded any fragments,
2221                    signal a receive error. */
2222                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2223                         skb_queue_walk_safe(list, p, tmp) {
2224                                 if (p == head)
2225                                         break;
2226                                 if (ppp->debug & 1)
2227                                         netdev_printk(KERN_DEBUG, ppp->dev,
2228                                                       "discarding frag %u\n",
2229                                                       PPP_MP_CB(p)->sequence);
2230                                 __skb_unlink(p, list);
2231                                 kfree_skb(p);
2232                         }
2233
2234                         if (ppp->debug & 1)
2235                                 netdev_printk(KERN_DEBUG, ppp->dev,
2236                                               "  missed pkts %u..%u\n",
2237                                               ppp->nextseq,
2238                                               PPP_MP_CB(head)->sequence-1);
2239                         ++ppp->dev->stats.rx_dropped;
2240                         ppp_receive_error(ppp);
2241                 }
2242
2243                 skb = head;
2244                 if (head != tail) {
2245                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2246                         p = skb_queue_next(list, head);
2247                         __skb_unlink(skb, list);
2248                         skb_queue_walk_from_safe(list, p, tmp) {
2249                                 __skb_unlink(p, list);
2250                                 *fragpp = p;
2251                                 p->next = NULL;
2252                                 fragpp = &p->next;
2253
2254                                 skb->len += p->len;
2255                                 skb->data_len += p->len;
2256                                 skb->truesize += p->truesize;
2257
2258                                 if (p == tail)
2259                                         break;
2260                         }
2261                 } else {
2262                         __skb_unlink(skb, list);
2263                 }
2264
2265                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2266         }
2267
2268         return skb;
2269 }
2270 #endif /* CONFIG_PPP_MULTILINK */
2271
2272 /*
2273  * Channel interface.
2274  */
2275
2276 /* Create a new, unattached ppp channel. */
2277 int ppp_register_channel(struct ppp_channel *chan)
2278 {
2279         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2280 }
2281
2282 /* Create a new, unattached ppp channel for specified net. */
2283 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2284 {
2285         struct channel *pch;
2286         struct ppp_net *pn;
2287
2288         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2289         if (!pch)
2290                 return -ENOMEM;
2291
2292         pn = ppp_pernet(net);
2293
2294         pch->ppp = NULL;
2295         pch->chan = chan;
2296         pch->chan_net = get_net(net);
2297         chan->ppp = pch;
2298         init_ppp_file(&pch->file, CHANNEL);
2299         pch->file.hdrlen = chan->hdrlen;
2300 #ifdef CONFIG_PPP_MULTILINK
2301         pch->lastseq = -1;
2302 #endif /* CONFIG_PPP_MULTILINK */
2303         init_rwsem(&pch->chan_sem);
2304         spin_lock_init(&pch->downl);
2305         rwlock_init(&pch->upl);
2306
2307         spin_lock_bh(&pn->all_channels_lock);
2308         pch->file.index = ++pn->last_channel_index;
2309         list_add(&pch->list, &pn->new_channels);
2310         atomic_inc(&channel_count);
2311         spin_unlock_bh(&pn->all_channels_lock);
2312
2313         return 0;
2314 }
2315
2316 /*
2317  * Return the index of a channel.
2318  */
2319 int ppp_channel_index(struct ppp_channel *chan)
2320 {
2321         struct channel *pch = chan->ppp;
2322
2323         if (pch)
2324                 return pch->file.index;
2325         return -1;
2326 }
2327
2328 /*
2329  * Return the PPP unit number to which a channel is connected.
2330  */
2331 int ppp_unit_number(struct ppp_channel *chan)
2332 {
2333         struct channel *pch = chan->ppp;
2334         int unit = -1;
2335
2336         if (pch) {
2337                 read_lock_bh(&pch->upl);
2338                 if (pch->ppp)
2339                         unit = pch->ppp->file.index;
2340                 read_unlock_bh(&pch->upl);
2341         }
2342         return unit;
2343 }
2344
2345 /*
2346  * Return the PPP device interface name of a channel.
2347  */
2348 char *ppp_dev_name(struct ppp_channel *chan)
2349 {
2350         struct channel *pch = chan->ppp;
2351         char *name = NULL;
2352
2353         if (pch) {
2354                 read_lock_bh(&pch->upl);
2355                 if (pch->ppp && pch->ppp->dev)
2356                         name = pch->ppp->dev->name;
2357                 read_unlock_bh(&pch->upl);
2358         }
2359         return name;
2360 }
2361
2362
2363 /*
2364  * Disconnect a channel from the generic layer.
2365  * This must be called in process context.
2366  */
2367 void
2368 ppp_unregister_channel(struct ppp_channel *chan)
2369 {
2370         struct channel *pch = chan->ppp;
2371         struct ppp_net *pn;
2372
2373         if (!pch)
2374                 return;         /* should never happen */
2375
2376         chan->ppp = NULL;
2377
2378         /*
2379          * This ensures that we have returned from any calls into the
2380          * the channel's start_xmit or ioctl routine before we proceed.
2381          */
2382         down_write(&pch->chan_sem);
2383         spin_lock_bh(&pch->downl);
2384         pch->chan = NULL;
2385         spin_unlock_bh(&pch->downl);
2386         up_write(&pch->chan_sem);
2387         ppp_disconnect_channel(pch);
2388
2389         pn = ppp_pernet(pch->chan_net);
2390         spin_lock_bh(&pn->all_channels_lock);
2391         list_del(&pch->list);
2392         spin_unlock_bh(&pn->all_channels_lock);
2393
2394         pch->file.dead = 1;
2395         wake_up_interruptible(&pch->file.rwait);
2396         if (atomic_dec_and_test(&pch->file.refcnt))
2397                 ppp_destroy_channel(pch);
2398 }
2399
2400 /*
2401  * Callback from a channel when it can accept more to transmit.
2402  * This should be called at BH/softirq level, not interrupt level.
2403  */
2404 void
2405 ppp_output_wakeup(struct ppp_channel *chan)
2406 {
2407         struct channel *pch = chan->ppp;
2408
2409         if (!pch)
2410                 return;
2411         ppp_channel_push(pch);
2412 }
2413
2414 /*
2415  * Compression control.
2416  */
2417
2418 /* Process the PPPIOCSCOMPRESS ioctl. */
2419 static int
2420 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2421 {
2422         int err;
2423         struct compressor *cp, *ocomp;
2424         struct ppp_option_data data;
2425         void *state, *ostate;
2426         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2427
2428         err = -EFAULT;
2429         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2430             (data.length <= CCP_MAX_OPTION_LENGTH &&
2431              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2432                 goto out;
2433         err = -EINVAL;
2434         if (data.length > CCP_MAX_OPTION_LENGTH ||
2435             ccp_option[1] < 2 || ccp_option[1] > data.length)
2436                 goto out;
2437
2438         cp = try_then_request_module(
2439                 find_compressor(ccp_option[0]),
2440                 "ppp-compress-%d", ccp_option[0]);
2441         if (!cp)
2442                 goto out;
2443
2444         err = -ENOBUFS;
2445         if (data.transmit) {
2446                 state = cp->comp_alloc(ccp_option, data.length);
2447                 if (state) {
2448                         ppp_xmit_lock(ppp);
2449                         ppp->xstate &= ~SC_COMP_RUN;
2450                         ocomp = ppp->xcomp;
2451                         ostate = ppp->xc_state;
2452                         ppp->xcomp = cp;
2453                         ppp->xc_state = state;
2454                         ppp_xmit_unlock(ppp);
2455                         if (ostate) {
2456                                 ocomp->comp_free(ostate);
2457                                 module_put(ocomp->owner);
2458                         }
2459                         err = 0;
2460                 } else
2461                         module_put(cp->owner);
2462
2463         } else {
2464                 state = cp->decomp_alloc(ccp_option, data.length);
2465                 if (state) {
2466                         ppp_recv_lock(ppp);
2467                         ppp->rstate &= ~SC_DECOMP_RUN;
2468                         ocomp = ppp->rcomp;
2469                         ostate = ppp->rc_state;
2470                         ppp->rcomp = cp;
2471                         ppp->rc_state = state;
2472                         ppp_recv_unlock(ppp);
2473                         if (ostate) {
2474                                 ocomp->decomp_free(ostate);
2475                                 module_put(ocomp->owner);
2476                         }
2477                         err = 0;
2478                 } else
2479                         module_put(cp->owner);
2480         }
2481
2482  out:
2483         return err;
2484 }
2485
2486 /*
2487  * Look at a CCP packet and update our state accordingly.
2488  * We assume the caller has the xmit or recv path locked.
2489  */
2490 static void
2491 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2492 {
2493         unsigned char *dp;
2494         int len;
2495
2496         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2497                 return; /* no header */
2498         dp = skb->data + 2;
2499
2500         switch (CCP_CODE(dp)) {
2501         case CCP_CONFREQ:
2502
2503                 /* A ConfReq starts negotiation of compression
2504                  * in one direction of transmission,
2505                  * and hence brings it down...but which way?
2506                  *
2507                  * Remember:
2508                  * A ConfReq indicates what the sender would like to receive
2509                  */
2510                 if(inbound)
2511                         /* He is proposing what I should send */
2512                         ppp->xstate &= ~SC_COMP_RUN;
2513                 else
2514                         /* I am proposing to what he should send */
2515                         ppp->rstate &= ~SC_DECOMP_RUN;
2516
2517                 break;
2518
2519         case CCP_TERMREQ:
2520         case CCP_TERMACK:
2521                 /*
2522                  * CCP is going down, both directions of transmission
2523                  */
2524                 ppp->rstate &= ~SC_DECOMP_RUN;
2525                 ppp->xstate &= ~SC_COMP_RUN;
2526                 break;
2527
2528         case CCP_CONFACK:
2529                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2530                         break;
2531                 len = CCP_LENGTH(dp);
2532                 if (!pskb_may_pull(skb, len + 2))
2533                         return;         /* too short */
2534                 dp += CCP_HDRLEN;
2535                 len -= CCP_HDRLEN;
2536                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2537                         break;
2538                 if (inbound) {
2539                         /* we will start receiving compressed packets */
2540                         if (!ppp->rc_state)
2541                                 break;
2542                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2543                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2544                                 ppp->rstate |= SC_DECOMP_RUN;
2545                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2546                         }
2547                 } else {
2548                         /* we will soon start sending compressed packets */
2549                         if (!ppp->xc_state)
2550                                 break;
2551                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2552                                         ppp->file.index, 0, ppp->debug))
2553                                 ppp->xstate |= SC_COMP_RUN;
2554                 }
2555                 break;
2556
2557         case CCP_RESETACK:
2558                 /* reset the [de]compressor */
2559                 if ((ppp->flags & SC_CCP_UP) == 0)
2560                         break;
2561                 if (inbound) {
2562                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2563                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2564                                 ppp->rstate &= ~SC_DC_ERROR;
2565                         }
2566                 } else {
2567                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2568                                 ppp->xcomp->comp_reset(ppp->xc_state);
2569                 }
2570                 break;
2571         }
2572 }
2573
2574 /* Free up compression resources. */
2575 static void
2576 ppp_ccp_closed(struct ppp *ppp)
2577 {
2578         void *xstate, *rstate;
2579         struct compressor *xcomp, *rcomp;
2580
2581         ppp_lock(ppp);
2582         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2583         ppp->xstate = 0;
2584         xcomp = ppp->xcomp;
2585         xstate = ppp->xc_state;
2586         ppp->xc_state = NULL;
2587         ppp->rstate = 0;
2588         rcomp = ppp->rcomp;
2589         rstate = ppp->rc_state;
2590         ppp->rc_state = NULL;
2591         ppp_unlock(ppp);
2592
2593         if (xstate) {
2594                 xcomp->comp_free(xstate);
2595                 module_put(xcomp->owner);
2596         }
2597         if (rstate) {
2598                 rcomp->decomp_free(rstate);
2599                 module_put(rcomp->owner);
2600         }
2601 }
2602
2603 /* List of compressors. */
2604 static LIST_HEAD(compressor_list);
2605 static DEFINE_SPINLOCK(compressor_list_lock);
2606
2607 struct compressor_entry {
2608         struct list_head list;
2609         struct compressor *comp;
2610 };
2611
2612 static struct compressor_entry *
2613 find_comp_entry(int proto)
2614 {
2615         struct compressor_entry *ce;
2616
2617         list_for_each_entry(ce, &compressor_list, list) {
2618                 if (ce->comp->compress_proto == proto)
2619                         return ce;
2620         }
2621         return NULL;
2622 }
2623
2624 /* Register a compressor */
2625 int
2626 ppp_register_compressor(struct compressor *cp)
2627 {
2628         struct compressor_entry *ce;
2629         int ret;
2630         spin_lock(&compressor_list_lock);
2631         ret = -EEXIST;
2632         if (find_comp_entry(cp->compress_proto))
2633                 goto out;
2634         ret = -ENOMEM;
2635         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2636         if (!ce)
2637                 goto out;
2638         ret = 0;
2639         ce->comp = cp;
2640         list_add(&ce->list, &compressor_list);
2641  out:
2642         spin_unlock(&compressor_list_lock);
2643         return ret;
2644 }
2645
2646 /* Unregister a compressor */
2647 void
2648 ppp_unregister_compressor(struct compressor *cp)
2649 {
2650         struct compressor_entry *ce;
2651
2652         spin_lock(&compressor_list_lock);
2653         ce = find_comp_entry(cp->compress_proto);
2654         if (ce && ce->comp == cp) {
2655                 list_del(&ce->list);
2656                 kfree(ce);
2657         }
2658         spin_unlock(&compressor_list_lock);
2659 }
2660
2661 /* Find a compressor. */
2662 static struct compressor *
2663 find_compressor(int type)
2664 {
2665         struct compressor_entry *ce;
2666         struct compressor *cp = NULL;
2667
2668         spin_lock(&compressor_list_lock);
2669         ce = find_comp_entry(type);
2670         if (ce) {
2671                 cp = ce->comp;
2672                 if (!try_module_get(cp->owner))
2673                         cp = NULL;
2674         }
2675         spin_unlock(&compressor_list_lock);
2676         return cp;
2677 }
2678
2679 /*
2680  * Miscelleneous stuff.
2681  */
2682
2683 static void
2684 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2685 {
2686         struct slcompress *vj = ppp->vj;
2687
2688         memset(st, 0, sizeof(*st));
2689         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2690         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2691         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2692         st->p.ppp_opackets = ppp->stats64.tx_packets;
2693         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2694         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2695         if (!vj)
2696                 return;
2697         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2698         st->vj.vjs_compressed = vj->sls_o_compressed;
2699         st->vj.vjs_searches = vj->sls_o_searches;
2700         st->vj.vjs_misses = vj->sls_o_misses;
2701         st->vj.vjs_errorin = vj->sls_i_error;
2702         st->vj.vjs_tossed = vj->sls_i_tossed;
2703         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2704         st->vj.vjs_compressedin = vj->sls_i_compressed;
2705 }
2706
2707 /*
2708  * Stuff for handling the lists of ppp units and channels
2709  * and for initialization.
2710  */
2711
2712 /*
2713  * Create a new ppp interface unit.  Fails if it can't allocate memory
2714  * or if there is already a unit with the requested number.
2715  * unit == -1 means allocate a new number.
2716  */
2717 static struct ppp *ppp_create_interface(struct net *net, int unit,
2718                                         struct file *file, int *retp)
2719 {
2720         struct ppp *ppp;
2721         struct ppp_net *pn;
2722         struct net_device *dev = NULL;
2723         int ret = -ENOMEM;
2724         int i;
2725
2726         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_UNKNOWN,
2727                            ppp_setup);
2728         if (!dev)
2729                 goto out1;
2730
2731         pn = ppp_pernet(net);
2732
2733         ppp = netdev_priv(dev);
2734         ppp->dev = dev;
2735         ppp->mru = PPP_MRU;
2736         init_ppp_file(&ppp->file, INTERFACE);
2737         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2738         ppp->owner = file;
2739         for (i = 0; i < NUM_NP; ++i)
2740                 ppp->npmode[i] = NPMODE_PASS;
2741         INIT_LIST_HEAD(&ppp->channels);
2742         spin_lock_init(&ppp->rlock);
2743         spin_lock_init(&ppp->wlock);
2744 #ifdef CONFIG_PPP_MULTILINK
2745         ppp->minseq = -1;
2746         skb_queue_head_init(&ppp->mrq);
2747 #endif /* CONFIG_PPP_MULTILINK */
2748 #ifdef CONFIG_PPP_FILTER
2749         ppp->pass_filter = NULL;
2750         ppp->active_filter = NULL;
2751 #endif /* CONFIG_PPP_FILTER */
2752
2753         /*
2754          * drum roll: don't forget to set
2755          * the net device is belong to
2756          */
2757         dev_net_set(dev, net);
2758
2759         rtnl_lock();
2760         mutex_lock(&pn->all_ppp_mutex);
2761
2762         if (unit < 0) {
2763                 unit = unit_get(&pn->units_idr, ppp);
2764                 if (unit < 0) {
2765                         ret = unit;
2766                         goto out2;
2767                 }
2768         } else {
2769                 ret = -EEXIST;
2770                 if (unit_find(&pn->units_idr, unit))
2771                         goto out2; /* unit already exists */
2772                 /*
2773                  * if caller need a specified unit number
2774                  * lets try to satisfy him, otherwise --
2775                  * he should better ask us for new unit number
2776                  *
2777                  * NOTE: yes I know that returning EEXIST it's not
2778                  * fair but at least pppd will ask us to allocate
2779                  * new unit in this case so user is happy :)
2780                  */
2781                 unit = unit_set(&pn->units_idr, ppp, unit);
2782                 if (unit < 0)
2783                         goto out2;
2784         }
2785
2786         /* Initialize the new ppp unit */
2787         ppp->file.index = unit;
2788         sprintf(dev->name, "ppp%d", unit);
2789
2790         ret = register_netdevice(dev);
2791         if (ret != 0) {
2792                 unit_put(&pn->units_idr, unit);
2793                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2794                            dev->name, ret);
2795                 goto out2;
2796         }
2797
2798         ppp->ppp_net = net;
2799
2800         atomic_inc(&ppp_unit_count);
2801         mutex_unlock(&pn->all_ppp_mutex);
2802         rtnl_unlock();
2803
2804         *retp = 0;
2805         return ppp;
2806
2807 out2:
2808         mutex_unlock(&pn->all_ppp_mutex);
2809         rtnl_unlock();
2810         free_netdev(dev);
2811 out1:
2812         *retp = ret;
2813         return NULL;
2814 }
2815
2816 /*
2817  * Initialize a ppp_file structure.
2818  */
2819 static void
2820 init_ppp_file(struct ppp_file *pf, int kind)
2821 {
2822         pf->kind = kind;
2823         skb_queue_head_init(&pf->xq);
2824         skb_queue_head_init(&pf->rq);
2825         atomic_set(&pf->refcnt, 1);
2826         init_waitqueue_head(&pf->rwait);
2827 }
2828
2829 /*
2830  * Free the memory used by a ppp unit.  This is only called once
2831  * there are no channels connected to the unit and no file structs
2832  * that reference the unit.
2833  */
2834 static void ppp_destroy_interface(struct ppp *ppp)
2835 {
2836         atomic_dec(&ppp_unit_count);
2837
2838         if (!ppp->file.dead || ppp->n_channels) {
2839                 /* "can't happen" */
2840                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2841                            "but dead=%d n_channels=%d !\n",
2842                            ppp, ppp->file.dead, ppp->n_channels);
2843                 return;
2844         }
2845
2846         ppp_ccp_closed(ppp);
2847         if (ppp->vj) {
2848                 slhc_free(ppp->vj);
2849                 ppp->vj = NULL;
2850         }
2851         skb_queue_purge(&ppp->file.xq);
2852         skb_queue_purge(&ppp->file.rq);
2853 #ifdef CONFIG_PPP_MULTILINK
2854         skb_queue_purge(&ppp->mrq);
2855 #endif /* CONFIG_PPP_MULTILINK */
2856 #ifdef CONFIG_PPP_FILTER
2857         if (ppp->pass_filter) {
2858                 bpf_prog_destroy(ppp->pass_filter);
2859                 ppp->pass_filter = NULL;
2860         }
2861
2862         if (ppp->active_filter) {
2863                 bpf_prog_destroy(ppp->active_filter);
2864                 ppp->active_filter = NULL;
2865         }
2866 #endif /* CONFIG_PPP_FILTER */
2867
2868         kfree_skb(ppp->xmit_pending);
2869
2870         free_netdev(ppp->dev);
2871 }
2872
2873 /*
2874  * Locate an existing ppp unit.
2875  * The caller should have locked the all_ppp_mutex.
2876  */
2877 static struct ppp *
2878 ppp_find_unit(struct ppp_net *pn, int unit)
2879 {
2880         return unit_find(&pn->units_idr, unit);
2881 }
2882
2883 /*
2884  * Locate an existing ppp channel.
2885  * The caller should have locked the all_channels_lock.
2886  * First we look in the new_channels list, then in the
2887  * all_channels list.  If found in the new_channels list,
2888  * we move it to the all_channels list.  This is for speed
2889  * when we have a lot of channels in use.
2890  */
2891 static struct channel *
2892 ppp_find_channel(struct ppp_net *pn, int unit)
2893 {
2894         struct channel *pch;
2895
2896         list_for_each_entry(pch, &pn->new_channels, list) {
2897                 if (pch->file.index == unit) {
2898                         list_move(&pch->list, &pn->all_channels);
2899                         return pch;
2900                 }
2901         }
2902
2903         list_for_each_entry(pch, &pn->all_channels, list) {
2904                 if (pch->file.index == unit)
2905                         return pch;
2906         }
2907
2908         return NULL;
2909 }
2910
2911 /*
2912  * Connect a PPP channel to a PPP interface unit.
2913  */
2914 static int
2915 ppp_connect_channel(struct channel *pch, int unit)
2916 {
2917         struct ppp *ppp;
2918         struct ppp_net *pn;
2919         int ret = -ENXIO;
2920         int hdrlen;
2921
2922         pn = ppp_pernet(pch->chan_net);
2923
2924         mutex_lock(&pn->all_ppp_mutex);
2925         ppp = ppp_find_unit(pn, unit);
2926         if (!ppp)
2927                 goto out;
2928         write_lock_bh(&pch->upl);
2929         ret = -EINVAL;
2930         if (pch->ppp)
2931                 goto outl;
2932
2933         ppp_lock(ppp);
2934         if (pch->file.hdrlen > ppp->file.hdrlen)
2935                 ppp->file.hdrlen = pch->file.hdrlen;
2936         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2937         if (hdrlen > ppp->dev->hard_header_len)
2938                 ppp->dev->hard_header_len = hdrlen;
2939         list_add_tail(&pch->clist, &ppp->channels);
2940         ++ppp->n_channels;
2941         pch->ppp = ppp;
2942         atomic_inc(&ppp->file.refcnt);
2943         ppp_unlock(ppp);
2944         ret = 0;
2945
2946  outl:
2947         write_unlock_bh(&pch->upl);
2948  out:
2949         mutex_unlock(&pn->all_ppp_mutex);
2950         return ret;
2951 }
2952
2953 /*
2954  * Disconnect a channel from its ppp unit.
2955  */
2956 static int
2957 ppp_disconnect_channel(struct channel *pch)
2958 {
2959         struct ppp *ppp;
2960         int err = -EINVAL;
2961
2962         write_lock_bh(&pch->upl);
2963         ppp = pch->ppp;
2964         pch->ppp = NULL;
2965         write_unlock_bh(&pch->upl);
2966         if (ppp) {
2967                 /* remove it from the ppp unit's list */
2968                 ppp_lock(ppp);
2969                 list_del(&pch->clist);
2970                 if (--ppp->n_channels == 0)
2971                         wake_up_interruptible(&ppp->file.rwait);
2972                 ppp_unlock(ppp);
2973                 if (atomic_dec_and_test(&ppp->file.refcnt))
2974                         ppp_destroy_interface(ppp);
2975                 err = 0;
2976         }
2977         return err;
2978 }
2979
2980 /*
2981  * Free up the resources used by a ppp channel.
2982  */
2983 static void ppp_destroy_channel(struct channel *pch)
2984 {
2985         put_net(pch->chan_net);
2986         pch->chan_net = NULL;
2987
2988         atomic_dec(&channel_count);
2989
2990         if (!pch->file.dead) {
2991                 /* "can't happen" */
2992                 pr_err("ppp: destroying undead channel %p !\n", pch);
2993                 return;
2994         }
2995         skb_queue_purge(&pch->file.xq);
2996         skb_queue_purge(&pch->file.rq);
2997         kfree(pch);
2998 }
2999
3000 static void __exit ppp_cleanup(void)
3001 {
3002         /* should never happen */
3003         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3004                 pr_err("PPP: removing module but units remain!\n");
3005         unregister_chrdev(PPP_MAJOR, "ppp");
3006         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3007         class_destroy(ppp_class);
3008         unregister_pernet_device(&ppp_net_ops);
3009 }
3010
3011 /*
3012  * Units handling. Caller must protect concurrent access
3013  * by holding all_ppp_mutex
3014  */
3015
3016 /* associate pointer with specified number */
3017 static int unit_set(struct idr *p, void *ptr, int n)
3018 {
3019         int unit;
3020
3021         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3022         if (unit == -ENOSPC)
3023                 unit = -EINVAL;
3024         return unit;
3025 }
3026
3027 /* get new free unit number and associate pointer with it */
3028 static int unit_get(struct idr *p, void *ptr)
3029 {
3030         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3031 }
3032
3033 /* put unit number back to a pool */
3034 static void unit_put(struct idr *p, int n)
3035 {
3036         idr_remove(p, n);
3037 }
3038
3039 /* get pointer associated with the number */
3040 static void *unit_find(struct idr *p, int n)
3041 {
3042         return idr_find(p, n);
3043 }
3044
3045 /* Module/initialization stuff */
3046
3047 module_init(ppp_init);
3048 module_exit(ppp_cleanup);
3049
3050 EXPORT_SYMBOL(ppp_register_net_channel);
3051 EXPORT_SYMBOL(ppp_register_channel);
3052 EXPORT_SYMBOL(ppp_unregister_channel);
3053 EXPORT_SYMBOL(ppp_channel_index);
3054 EXPORT_SYMBOL(ppp_unit_number);
3055 EXPORT_SYMBOL(ppp_dev_name);
3056 EXPORT_SYMBOL(ppp_input);
3057 EXPORT_SYMBOL(ppp_input_error);
3058 EXPORT_SYMBOL(ppp_output_wakeup);
3059 EXPORT_SYMBOL(ppp_register_compressor);
3060 EXPORT_SYMBOL(ppp_unregister_compressor);
3061 MODULE_LICENSE("GPL");
3062 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3063 MODULE_ALIAS("devname:ppp");