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         mutex_destroy(&pn->all_ppp_mutex);
 946         idr_destroy(&pn->units_idr);
 947 }
 948
 949 static struct pernet_operations ppp_net_ops = {
 950         .init = ppp_init_net,
 951         .exit = ppp_exit_net,
 952         .id   = &ppp_net_id,
 953         .size = sizeof(struct ppp_net),
 954 };
 955
 956 #define PPP_MAJOR       108
 957
 958 /* Called at boot time if ppp is compiled into the kernel,
 959    or at module load time (from init_module) if compiled as a module. */
 960 static int __init ppp_init(void)
 961 {
 962         int err;
 963
 964         pr_info("PPP generic driver version " PPP_VERSION "\n");
 965
 966         err = register_pernet_device(&ppp_net_ops);
 967         if (err) {
 968                 pr_err("failed to register PPP pernet device (%d)\n", err);
 969                 goto out;
 970         }
 971
 972         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 973         if (err) {
 974                 pr_err("failed to register PPP device (%d)\n", err);
 975                 goto out_net;
 976         }
 977
 978         ppp_class = class_create(THIS_MODULE, "ppp");
 979         if (IS_ERR(ppp_class)) {
 980                 err = PTR_ERR(ppp_class);
 981                 goto out_chrdev;
 982         }
 983
 984         /* not a big deal if we fail here :-) */
 985         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 986
 987         return 0;
 988
 989 out_chrdev:
 990         unregister_chrdev(PPP_MAJOR, "ppp");
 991 out_net:
 992         unregister_pernet_device(&ppp_net_ops);
 993 out:
 994         return err;
 995 }
 996
 997 /*
 998  * Network interface unit routines.
 999  */
1000 static netdev_tx_t
1001 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1002 {
1003         struct ppp *ppp = netdev_priv(dev);
1004         int npi, proto;
1005         unsigned char *pp;
1006
1007         npi = ethertype_to_npindex(ntohs(skb->protocol));
1008         if (npi < 0)
1009                 goto outf;
1010
1011         /* Drop, accept or reject the packet */
1012         switch (ppp->npmode[npi]) {
1013         case NPMODE_PASS:
1014                 break;
1015         case NPMODE_QUEUE:
1016                 /* it would be nice to have a way to tell the network
1017                    system to queue this one up for later. */
1018                 goto outf;
1019         case NPMODE_DROP:
1020         case NPMODE_ERROR:
1021                 goto outf;
1022         }
1023
1024         /* Put the 2-byte PPP protocol number on the front,
1025            making sure there is room for the address and control fields. */
1026         if (skb_cow_head(skb, PPP_HDRLEN))
1027                 goto outf;
1028
1029         pp = skb_push(skb, 2);
1030         proto = npindex_to_proto[npi];
1031         put_unaligned_be16(proto, pp);
1032
1033         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1034         skb_queue_tail(&ppp->file.xq, skb);
1035         ppp_xmit_process(ppp);
1036         return NETDEV_TX_OK;
1037
1038  outf:
1039         kfree_skb(skb);
1040         ++dev->stats.tx_dropped;
1041         return NETDEV_TX_OK;
1042 }
1043
1044 static int
1045 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1046 {
1047         struct ppp *ppp = netdev_priv(dev);
1048         int err = -EFAULT;
1049         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1050         struct ppp_stats stats;
1051         struct ppp_comp_stats cstats;
1052         char *vers;
1053
1054         switch (cmd) {
1055         case SIOCGPPPSTATS:
1056                 ppp_get_stats(ppp, &stats);
1057                 if (copy_to_user(addr, &stats, sizeof(stats)))
1058                         break;
1059                 err = 0;
1060                 break;
1061
1062         case SIOCGPPPCSTATS:
1063                 memset(&cstats, 0, sizeof(cstats));
1064                 if (ppp->xc_state)
1065                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1066                 if (ppp->rc_state)
1067                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1068                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1069                         break;
1070                 err = 0;
1071                 break;
1072
1073         case SIOCGPPPVER:
1074                 vers = PPP_VERSION;
1075                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1076                         break;
1077                 err = 0;
1078                 break;
1079
1080         default:
1081                 err = -EINVAL;
1082         }
1083
1084         return err;
1085 }
1086
1087 static struct rtnl_link_stats64*
1088 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1089 {
1090         struct ppp *ppp = netdev_priv(dev);
1091
1092         ppp_recv_lock(ppp);
1093         stats64->rx_packets = ppp->stats64.rx_packets;
1094         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1095         ppp_recv_unlock(ppp);
1096
1097         ppp_xmit_lock(ppp);
1098         stats64->tx_packets = ppp->stats64.tx_packets;
1099         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1100         ppp_xmit_unlock(ppp);
1101
1102         stats64->rx_errors        = dev->stats.rx_errors;
1103         stats64->tx_errors        = dev->stats.tx_errors;
1104         stats64->rx_dropped       = dev->stats.rx_dropped;
1105         stats64->tx_dropped       = dev->stats.tx_dropped;
1106         stats64->rx_length_errors = dev->stats.rx_length_errors;
1107
1108         return stats64;
1109 }
1110
1111 static struct lock_class_key ppp_tx_busylock;
1112 static int ppp_dev_init(struct net_device *dev)
1113 {
1114         struct ppp *ppp;
1115
1116         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1117
1118         ppp = netdev_priv(dev);
1119         /* Let the netdevice take a reference on the ppp file. This ensures
1120          * that ppp_destroy_interface() won't run before the device gets
1121          * unregistered.
1122          */
1123         atomic_inc(&ppp->file.refcnt);
1124
1125         return 0;
1126 }
1127
1128 static void ppp_dev_uninit(struct net_device *dev)
1129 {
1130         struct ppp *ppp = netdev_priv(dev);
1131         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1132
1133         ppp_lock(ppp);
1134         ppp->closing = 1;
1135         ppp_unlock(ppp);
1136
1137         mutex_lock(&pn->all_ppp_mutex);
1138         unit_put(&pn->units_idr, ppp->file.index);
1139         mutex_unlock(&pn->all_ppp_mutex);
1140
1141         ppp->owner = NULL;
1142
1143         ppp->file.dead = 1;
1144         wake_up_interruptible(&ppp->file.rwait);
1145 }
1146
1147 static void ppp_dev_priv_destructor(struct net_device *dev)
1148 {
1149         struct ppp *ppp;
1150
1151         ppp = netdev_priv(dev);
1152         if (atomic_dec_and_test(&ppp->file.refcnt))
1153                 ppp_destroy_interface(ppp);
1154 }
1155
1156 static const struct net_device_ops ppp_netdev_ops = {
1157         .ndo_init        = ppp_dev_init,
1158         .ndo_uninit      = ppp_dev_uninit,
1159         .ndo_start_xmit  = ppp_start_xmit,
1160         .ndo_do_ioctl    = ppp_net_ioctl,
1161         .ndo_get_stats64 = ppp_get_stats64,
1162 };
1163
1164 static void ppp_setup(struct net_device *dev)
1165 {
1166         dev->netdev_ops = &ppp_netdev_ops;
1167         dev->hard_header_len = PPP_HDRLEN;
1168         dev->mtu = PPP_MRU;
1169         dev->addr_len = 0;
1170         dev->tx_queue_len = 3;
1171         dev->type = ARPHRD_PPP;
1172         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1173         dev->destructor = ppp_dev_priv_destructor;
1174         netif_keep_dst(dev);
1175 }
1176
1177 /*
1178  * Transmit-side routines.
1179  */
1180
1181 /*
1182  * Called to do any work queued up on the transmit side
1183  * that can now be done.
1184  */
1185 static void
1186 ppp_xmit_process(struct ppp *ppp)
1187 {
1188         struct sk_buff *skb;
1189
1190         ppp_xmit_lock(ppp);
1191         if (!ppp->closing) {
1192                 ppp_push(ppp);
1193                 while (!ppp->xmit_pending &&
1194                        (skb = skb_dequeue(&ppp->file.xq)))
1195                         ppp_send_frame(ppp, skb);
1196                 /* If there's no work left to do, tell the core net
1197                    code that we can accept some more. */
1198                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1199                         netif_wake_queue(ppp->dev);
1200                 else
1201                         netif_stop_queue(ppp->dev);
1202         }
1203         ppp_xmit_unlock(ppp);
1204 }
1205
1206 static inline struct sk_buff *
1207 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1208 {
1209         struct sk_buff *new_skb;
1210         int len;
1211         int new_skb_size = ppp->dev->mtu +
1212                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1213         int compressor_skb_size = ppp->dev->mtu +
1214                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1215         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1216         if (!new_skb) {
1217                 if (net_ratelimit())
1218                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1219                 return NULL;
1220         }
1221         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1222                 skb_reserve(new_skb,
1223                             ppp->dev->hard_header_len - PPP_HDRLEN);
1224
1225         /* compressor still expects A/C bytes in hdr */
1226         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1227                                    new_skb->data, skb->len + 2,
1228                                    compressor_skb_size);
1229         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1230                 consume_skb(skb);
1231                 skb = new_skb;
1232                 skb_put(skb, len);
1233                 skb_pull(skb, 2);       /* pull off A/C bytes */
1234         } else if (len == 0) {
1235                 /* didn't compress, or CCP not up yet */
1236                 consume_skb(new_skb);
1237                 new_skb = skb;
1238         } else {
1239                 /*
1240                  * (len < 0)
1241                  * MPPE requires that we do not send unencrypted
1242                  * frames.  The compressor will return -1 if we
1243                  * should drop the frame.  We cannot simply test
1244                  * the compress_proto because MPPE and MPPC share
1245                  * the same number.
1246                  */
1247                 if (net_ratelimit())
1248                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1249                 kfree_skb(skb);
1250                 consume_skb(new_skb);
1251                 new_skb = NULL;
1252         }
1253         return new_skb;
1254 }
1255
1256 /*
1257  * Compress and send a frame.
1258  * The caller should have locked the xmit path,
1259  * and xmit_pending should be 0.
1260  */
1261 static void
1262 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1263 {
1264         int proto = PPP_PROTO(skb);
1265         struct sk_buff *new_skb;
1266         int len;
1267         unsigned char *cp;
1268
1269         if (proto < 0x8000) {
1270 #ifdef CONFIG_PPP_FILTER
1271                 /* check if we should pass this packet */
1272                 /* the filter instructions are constructed assuming
1273                    a four-byte PPP header on each packet */
1274                 *skb_push(skb, 2) = 1;
1275                 if (ppp->pass_filter &&
1276                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1277                         if (ppp->debug & 1)
1278                                 netdev_printk(KERN_DEBUG, ppp->dev,
1279                                               "PPP: outbound frame "
1280                                               "not passed\n");
1281                         kfree_skb(skb);
1282                         return;
1283                 }
1284                 /* if this packet passes the active filter, record the time */
1285                 if (!(ppp->active_filter &&
1286                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1287                         ppp->last_xmit = jiffies;
1288                 skb_pull(skb, 2);
1289 #else
1290                 /* for data packets, record the time */
1291                 ppp->last_xmit = jiffies;
1292 #endif /* CONFIG_PPP_FILTER */
1293         }
1294
1295         ++ppp->stats64.tx_packets;
1296         ppp->stats64.tx_bytes += skb->len - 2;
1297
1298         switch (proto) {
1299         case PPP_IP:
1300                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1301                         break;
1302                 /* try to do VJ TCP header compression */
1303                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1304                                     GFP_ATOMIC);
1305                 if (!new_skb) {
1306                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1307                         goto drop;
1308                 }
1309                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1310                 cp = skb->data + 2;
1311                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1312                                     new_skb->data + 2, &cp,
1313                                     !(ppp->flags & SC_NO_TCP_CCID));
1314                 if (cp == skb->data + 2) {
1315                         /* didn't compress */
1316                         consume_skb(new_skb);
1317                 } else {
1318                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1319                                 proto = PPP_VJC_COMP;
1320                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1321                         } else {
1322                                 proto = PPP_VJC_UNCOMP;
1323                                 cp[0] = skb->data[2];
1324                         }
1325                         consume_skb(skb);
1326                         skb = new_skb;
1327                         cp = skb_put(skb, len + 2);
1328                         cp[0] = 0;
1329                         cp[1] = proto;
1330                 }
1331                 break;
1332
1333         case PPP_CCP:
1334                 /* peek at outbound CCP frames */
1335                 ppp_ccp_peek(ppp, skb, 0);
1336                 break;
1337         }
1338
1339         /* try to do packet compression */
1340         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1341             proto != PPP_LCP && proto != PPP_CCP) {
1342                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1343                         if (net_ratelimit())
1344                                 netdev_err(ppp->dev,
1345                                            "ppp: compression required but "
1346                                            "down - pkt dropped.\n");
1347                         goto drop;
1348                 }
1349                 skb = pad_compress_skb(ppp, skb);
1350                 if (!skb)
1351                         goto drop;
1352         }
1353
1354         /*
1355          * If we are waiting for traffic (demand dialling),
1356          * queue it up for pppd to receive.
1357          */
1358         if (ppp->flags & SC_LOOP_TRAFFIC) {
1359                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1360                         goto drop;
1361                 skb_queue_tail(&ppp->file.rq, skb);
1362                 wake_up_interruptible(&ppp->file.rwait);
1363                 return;
1364         }
1365
1366         ppp->xmit_pending = skb;
1367         ppp_push(ppp);
1368         return;
1369
1370  drop:
1371         kfree_skb(skb);
1372         ++ppp->dev->stats.tx_errors;
1373 }
1374
1375 /*
1376  * Try to send the frame in xmit_pending.
1377  * The caller should have the xmit path locked.
1378  */
1379 static void
1380 ppp_push(struct ppp *ppp)
1381 {
1382         struct list_head *list;
1383         struct channel *pch;
1384         struct sk_buff *skb = ppp->xmit_pending;
1385
1386         if (!skb)
1387                 return;
1388
1389         list = &ppp->channels;
1390         if (list_empty(list)) {
1391                 /* nowhere to send the packet, just drop it */
1392                 ppp->xmit_pending = NULL;
1393                 kfree_skb(skb);
1394                 return;
1395         }
1396
1397         if ((ppp->flags & SC_MULTILINK) == 0) {
1398                 /* not doing multilink: send it down the first channel */
1399                 list = list->next;
1400                 pch = list_entry(list, struct channel, clist);
1401
1402                 spin_lock_bh(&pch->downl);
1403                 if (pch->chan) {
1404                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1405                                 ppp->xmit_pending = NULL;
1406                 } else {
1407                         /* channel got unregistered */
1408                         kfree_skb(skb);
1409                         ppp->xmit_pending = NULL;
1410                 }
1411                 spin_unlock_bh(&pch->downl);
1412                 return;
1413         }
1414
1415 #ifdef CONFIG_PPP_MULTILINK
1416         /* Multilink: fragment the packet over as many links
1417            as can take the packet at the moment. */
1418         if (!ppp_mp_explode(ppp, skb))
1419                 return;
1420 #endif /* CONFIG_PPP_MULTILINK */
1421
1422         ppp->xmit_pending = NULL;
1423         kfree_skb(skb);
1424 }
1425
1426 #ifdef CONFIG_PPP_MULTILINK
1427 static bool mp_protocol_compress __read_mostly = true;
1428 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1429 MODULE_PARM_DESC(mp_protocol_compress,
1430                  "compress protocol id in multilink fragments");
1431
1432 /*
1433  * Divide a packet to be transmitted into fragments and
1434  * send them out the individual links.
1435  */
1436 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1437 {
1438         int len, totlen;
1439         int i, bits, hdrlen, mtu;
1440         int flen;
1441         int navail, nfree, nzero;
1442         int nbigger;
1443         int totspeed;
1444         int totfree;
1445         unsigned char *p, *q;
1446         struct list_head *list;
1447         struct channel *pch;
1448         struct sk_buff *frag;
1449         struct ppp_channel *chan;
1450
1451         totspeed = 0; /*total bitrate of the bundle*/
1452         nfree = 0; /* # channels which have no packet already queued */
1453         navail = 0; /* total # of usable channels (not deregistered) */
1454         nzero = 0; /* number of channels with zero speed associated*/
1455         totfree = 0; /*total # of channels available and
1456                                   *having no queued packets before
1457                                   *starting the fragmentation*/
1458
1459         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1460         i = 0;
1461         list_for_each_entry(pch, &ppp->channels, clist) {
1462                 if (pch->chan) {
1463                         pch->avail = 1;
1464                         navail++;
1465                         pch->speed = pch->chan->speed;
1466                 } else {
1467                         pch->avail = 0;
1468                 }
1469                 if (pch->avail) {
1470                         if (skb_queue_empty(&pch->file.xq) ||
1471                                 !pch->had_frag) {
1472                                         if (pch->speed == 0)
1473                                                 nzero++;
1474                                         else
1475                                                 totspeed += pch->speed;
1476
1477                                         pch->avail = 2;
1478                                         ++nfree;
1479                                         ++totfree;
1480                                 }
1481                         if (!pch->had_frag && i < ppp->nxchan)
1482                                 ppp->nxchan = i;
1483                 }
1484                 ++i;
1485         }
1486         /*
1487          * Don't start sending this packet unless at least half of
1488          * the channels are free.  This gives much better TCP
1489          * performance if we have a lot of channels.
1490          */
1491         if (nfree == 0 || nfree < navail / 2)
1492                 return 0; /* can't take now, leave it in xmit_pending */
1493
1494         /* Do protocol field compression */
1495         p = skb->data;
1496         len = skb->len;
1497         if (*p == 0 && mp_protocol_compress) {
1498                 ++p;
1499                 --len;
1500         }
1501
1502         totlen = len;
1503         nbigger = len % nfree;
1504
1505         /* skip to the channel after the one we last used
1506            and start at that one */
1507         list = &ppp->channels;
1508         for (i = 0; i < ppp->nxchan; ++i) {
1509                 list = list->next;
1510                 if (list == &ppp->channels) {
1511                         i = 0;
1512                         break;
1513                 }
1514         }
1515
1516         /* create a fragment for each channel */
1517         bits = B;
1518         while (len > 0) {
1519                 list = list->next;
1520                 if (list == &ppp->channels) {
1521                         i = 0;
1522                         continue;
1523                 }
1524                 pch = list_entry(list, struct channel, clist);
1525                 ++i;
1526                 if (!pch->avail)
1527                         continue;
1528
1529                 /*
1530                  * Skip this channel if it has a fragment pending already and
1531                  * we haven't given a fragment to all of the free channels.
1532                  */
1533                 if (pch->avail == 1) {
1534                         if (nfree > 0)
1535                                 continue;
1536                 } else {
1537                         pch->avail = 1;
1538                 }
1539
1540                 /* check the channel's mtu and whether it is still attached. */
1541                 spin_lock_bh(&pch->downl);
1542                 if (pch->chan == NULL) {
1543                         /* can't use this channel, it's being deregistered */
1544                         if (pch->speed == 0)
1545                                 nzero--;
1546                         else
1547                                 totspeed -= pch->speed;
1548
1549                         spin_unlock_bh(&pch->downl);
1550                         pch->avail = 0;
1551                         totlen = len;
1552                         totfree--;
1553                         nfree--;
1554                         if (--navail == 0)
1555                                 break;
1556                         continue;
1557                 }
1558
1559                 /*
1560                 *if the channel speed is not set divide
1561                 *the packet evenly among the free channels;
1562                 *otherwise divide it according to the speed
1563                 *of the channel we are going to transmit on
1564                 */
1565                 flen = len;
1566                 if (nfree > 0) {
1567                         if (pch->speed == 0) {
1568                                 flen = len/nfree;
1569                                 if (nbigger > 0) {
1570                                         flen++;
1571                                         nbigger--;
1572                                 }
1573                         } else {
1574                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1575                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1576                                 if (nbigger > 0) {
1577                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1578                                         nbigger -= ((totfree - nzero)*pch->speed)/
1579                                                         totspeed;
1580                                 }
1581                         }
1582                         nfree--;
1583                 }
1584
1585                 /*
1586                  *check if we are on the last channel or
1587                  *we exceded the length of the data to
1588                  *fragment
1589                  */
1590                 if ((nfree <= 0) || (flen > len))
1591                         flen = len;
1592                 /*
1593                  *it is not worth to tx on slow channels:
1594                  *in that case from the resulting flen according to the
1595                  *above formula will be equal or less than zero.
1596                  *Skip the channel in this case
1597                  */
1598                 if (flen <= 0) {
1599                         pch->avail = 2;
1600                         spin_unlock_bh(&pch->downl);
1601                         continue;
1602                 }
1603
1604                 /*
1605                  * hdrlen includes the 2-byte PPP protocol field, but the
1606                  * MTU counts only the payload excluding the protocol field.
1607                  * (RFC1661 Section 2)
1608                  */
1609                 mtu = pch->chan->mtu - (hdrlen - 2);
1610                 if (mtu < 4)
1611                         mtu = 4;
1612                 if (flen > mtu)
1613                         flen = mtu;
1614                 if (flen == len)
1615                         bits |= E;
1616                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1617                 if (!frag)
1618                         goto noskb;
1619                 q = skb_put(frag, flen + hdrlen);
1620
1621                 /* make the MP header */
1622                 put_unaligned_be16(PPP_MP, q);
1623                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1624                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1625                         q[3] = ppp->nxseq;
1626                 } else {
1627                         q[2] = bits;
1628                         q[3] = ppp->nxseq >> 16;
1629                         q[4] = ppp->nxseq >> 8;
1630                         q[5] = ppp->nxseq;
1631                 }
1632
1633                 memcpy(q + hdrlen, p, flen);
1634
1635                 /* try to send it down the channel */
1636                 chan = pch->chan;
1637                 if (!skb_queue_empty(&pch->file.xq) ||
1638                         !chan->ops->start_xmit(chan, frag))
1639                         skb_queue_tail(&pch->file.xq, frag);
1640                 pch->had_frag = 1;
1641                 p += flen;
1642                 len -= flen;
1643                 ++ppp->nxseq;
1644                 bits = 0;
1645                 spin_unlock_bh(&pch->downl);
1646         }
1647         ppp->nxchan = i;
1648
1649         return 1;
1650
1651  noskb:
1652         spin_unlock_bh(&pch->downl);
1653         if (ppp->debug & 1)
1654                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1655         ++ppp->dev->stats.tx_errors;
1656         ++ppp->nxseq;
1657         return 1;       /* abandon the frame */
1658 }
1659 #endif /* CONFIG_PPP_MULTILINK */
1660
1661 /*
1662  * Try to send data out on a channel.
1663  */
1664 static void
1665 ppp_channel_push(struct channel *pch)
1666 {
1667         struct sk_buff *skb;
1668         struct ppp *ppp;
1669
1670         spin_lock_bh(&pch->downl);
1671         if (pch->chan) {
1672                 while (!skb_queue_empty(&pch->file.xq)) {
1673                         skb = skb_dequeue(&pch->file.xq);
1674                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1675                                 /* put the packet back and try again later */
1676                                 skb_queue_head(&pch->file.xq, skb);
1677                                 break;
1678                         }
1679                 }
1680         } else {
1681                 /* channel got deregistered */
1682                 skb_queue_purge(&pch->file.xq);
1683         }
1684         spin_unlock_bh(&pch->downl);
1685         /* see if there is anything from the attached unit to be sent */
1686         if (skb_queue_empty(&pch->file.xq)) {
1687                 read_lock_bh(&pch->upl);
1688                 ppp = pch->ppp;
1689                 if (ppp)
1690                         ppp_xmit_process(ppp);
1691                 read_unlock_bh(&pch->upl);
1692         }
1693 }
1694
1695 /*
1696  * Receive-side routines.
1697  */
1698
1699 struct ppp_mp_skb_parm {
1700         u32             sequence;
1701         u8              BEbits;
1702 };
1703 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1704
1705 static inline void
1706 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1707 {
1708         ppp_recv_lock(ppp);
1709         if (!ppp->closing)
1710                 ppp_receive_frame(ppp, skb, pch);
1711         else
1712                 kfree_skb(skb);
1713         ppp_recv_unlock(ppp);
1714 }
1715
1716 void
1717 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1718 {
1719         struct channel *pch = chan->ppp;
1720         int proto;
1721
1722         if (!pch) {
1723                 kfree_skb(skb);
1724                 return;
1725         }
1726
1727         read_lock_bh(&pch->upl);
1728         if (!pskb_may_pull(skb, 2)) {
1729                 kfree_skb(skb);
1730                 if (pch->ppp) {
1731                         ++pch->ppp->dev->stats.rx_length_errors;
1732                         ppp_receive_error(pch->ppp);
1733                 }
1734                 goto done;
1735         }
1736
1737         proto = PPP_PROTO(skb);
1738         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1739                 /* put it on the channel queue */
1740                 skb_queue_tail(&pch->file.rq, skb);
1741                 /* drop old frames if queue too long */
1742                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1743                        (skb = skb_dequeue(&pch->file.rq)))
1744                         kfree_skb(skb);
1745                 wake_up_interruptible(&pch->file.rwait);
1746         } else {
1747                 ppp_do_recv(pch->ppp, skb, pch);
1748         }
1749
1750 done:
1751         read_unlock_bh(&pch->upl);
1752 }
1753
1754 /* Put a 0-length skb in the receive queue as an error indication */
1755 void
1756 ppp_input_error(struct ppp_channel *chan, int code)
1757 {
1758         struct channel *pch = chan->ppp;
1759         struct sk_buff *skb;
1760
1761         if (!pch)
1762                 return;
1763
1764         read_lock_bh(&pch->upl);
1765         if (pch->ppp) {
1766                 skb = alloc_skb(0, GFP_ATOMIC);
1767                 if (skb) {
1768                         skb->len = 0;           /* probably unnecessary */
1769                         skb->cb[0] = code;
1770                         ppp_do_recv(pch->ppp, skb, pch);
1771                 }
1772         }
1773         read_unlock_bh(&pch->upl);
1774 }
1775
1776 /*
1777  * We come in here to process a received frame.
1778  * The receive side of the ppp unit is locked.
1779  */
1780 static void
1781 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1782 {
1783         /* note: a 0-length skb is used as an error indication */
1784         if (skb->len > 0) {
1785                 skb_checksum_complete_unset(skb);
1786 #ifdef CONFIG_PPP_MULTILINK
1787                 /* XXX do channel-level decompression here */
1788                 if (PPP_PROTO(skb) == PPP_MP)
1789                         ppp_receive_mp_frame(ppp, skb, pch);
1790                 else
1791 #endif /* CONFIG_PPP_MULTILINK */
1792                         ppp_receive_nonmp_frame(ppp, skb);
1793         } else {
1794                 kfree_skb(skb);
1795                 ppp_receive_error(ppp);
1796         }
1797 }
1798
1799 static void
1800 ppp_receive_error(struct ppp *ppp)
1801 {
1802         ++ppp->dev->stats.rx_errors;
1803         if (ppp->vj)
1804                 slhc_toss(ppp->vj);
1805 }
1806
1807 static void
1808 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1809 {
1810         struct sk_buff *ns;
1811         int proto, len, npi;
1812
1813         /*
1814          * Decompress the frame, if compressed.
1815          * Note that some decompressors need to see uncompressed frames
1816          * that come in as well as compressed frames.
1817          */
1818         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1819             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1820                 skb = ppp_decompress_frame(ppp, skb);
1821
1822         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1823                 goto err;
1824
1825         proto = PPP_PROTO(skb);
1826         switch (proto) {
1827         case PPP_VJC_COMP:
1828                 /* decompress VJ compressed packets */
1829                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1830                         goto err;
1831
1832                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1833                         /* copy to a new sk_buff with more tailroom */
1834                         ns = dev_alloc_skb(skb->len + 128);
1835                         if (!ns) {
1836                                 netdev_err(ppp->dev, "PPP: no memory "
1837                                            "(VJ decomp)\n");
1838                                 goto err;
1839                         }
1840                         skb_reserve(ns, 2);
1841                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1842                         consume_skb(skb);
1843                         skb = ns;
1844                 }
1845                 else
1846                         skb->ip_summed = CHECKSUM_NONE;
1847
1848                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1849                 if (len <= 0) {
1850                         netdev_printk(KERN_DEBUG, ppp->dev,
1851                                       "PPP: VJ decompression error\n");
1852                         goto err;
1853                 }
1854                 len += 2;
1855                 if (len > skb->len)
1856                         skb_put(skb, len - skb->len);
1857                 else if (len < skb->len)
1858                         skb_trim(skb, len);
1859                 proto = PPP_IP;
1860                 break;
1861
1862         case PPP_VJC_UNCOMP:
1863                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1864                         goto err;
1865
1866                 /* Until we fix the decompressor need to make sure
1867                  * data portion is linear.
1868                  */
1869                 if (!pskb_may_pull(skb, skb->len))
1870                         goto err;
1871
1872                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1873                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1874                         goto err;
1875                 }
1876                 proto = PPP_IP;
1877                 break;
1878
1879         case PPP_CCP:
1880                 ppp_ccp_peek(ppp, skb, 1);
1881                 break;
1882         }
1883
1884         ++ppp->stats64.rx_packets;
1885         ppp->stats64.rx_bytes += skb->len - 2;
1886
1887         npi = proto_to_npindex(proto);
1888         if (npi < 0) {
1889                 /* control or unknown frame - pass it to pppd */
1890                 skb_queue_tail(&ppp->file.rq, skb);
1891                 /* limit queue length by dropping old frames */
1892                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1893                        (skb = skb_dequeue(&ppp->file.rq)))
1894                         kfree_skb(skb);
1895                 /* wake up any process polling or blocking on read */
1896                 wake_up_interruptible(&ppp->file.rwait);
1897
1898         } else {
1899                 /* network protocol frame - give it to the kernel */
1900
1901 #ifdef CONFIG_PPP_FILTER
1902                 /* check if the packet passes the pass and active filters */
1903                 /* the filter instructions are constructed assuming
1904                    a four-byte PPP header on each packet */
1905                 if (ppp->pass_filter || ppp->active_filter) {
1906                         if (skb_unclone(skb, GFP_ATOMIC))
1907                                 goto err;
1908
1909                         *skb_push(skb, 2) = 0;
1910                         if (ppp->pass_filter &&
1911                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1912                                 if (ppp->debug & 1)
1913                                         netdev_printk(KERN_DEBUG, ppp->dev,
1914                                                       "PPP: inbound frame "
1915                                                       "not passed\n");
1916                                 kfree_skb(skb);
1917                                 return;
1918                         }
1919                         if (!(ppp->active_filter &&
1920                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1921                                 ppp->last_recv = jiffies;
1922                         __skb_pull(skb, 2);
1923                 } else
1924 #endif /* CONFIG_PPP_FILTER */
1925                         ppp->last_recv = jiffies;
1926
1927                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1928                     ppp->npmode[npi] != NPMODE_PASS) {
1929                         kfree_skb(skb);
1930                 } else {
1931                         /* chop off protocol */
1932                         skb_pull_rcsum(skb, 2);
1933                         skb->dev = ppp->dev;
1934                         skb->protocol = htons(npindex_to_ethertype[npi]);
1935                         skb_reset_mac_header(skb);
1936                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
1937                                                       dev_net(ppp->dev)));
1938                         netif_rx(skb);
1939                 }
1940         }
1941         return;
1942
1943  err:
1944         kfree_skb(skb);
1945         ppp_receive_error(ppp);
1946 }
1947
1948 static struct sk_buff *
1949 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1950 {
1951         int proto = PPP_PROTO(skb);
1952         struct sk_buff *ns;
1953         int len;
1954
1955         /* Until we fix all the decompressor's need to make sure
1956          * data portion is linear.
1957          */
1958         if (!pskb_may_pull(skb, skb->len))
1959                 goto err;
1960
1961         if (proto == PPP_COMP) {
1962                 int obuff_size;
1963
1964                 switch(ppp->rcomp->compress_proto) {
1965                 case CI_MPPE:
1966                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1967                         break;
1968                 default:
1969                         obuff_size = ppp->mru + PPP_HDRLEN;
1970                         break;
1971                 }
1972
1973                 ns = dev_alloc_skb(obuff_size);
1974                 if (!ns) {
1975                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1976                                    "no memory\n");
1977                         goto err;
1978                 }
1979                 /* the decompressor still expects the A/C bytes in the hdr */
1980                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1981                                 skb->len + 2, ns->data, obuff_size);
1982                 if (len < 0) {
1983                         /* Pass the compressed frame to pppd as an
1984                            error indication. */
1985                         if (len == DECOMP_FATALERROR)
1986                                 ppp->rstate |= SC_DC_FERROR;
1987                         kfree_skb(ns);
1988                         goto err;
1989                 }
1990
1991                 consume_skb(skb);
1992                 skb = ns;
1993                 skb_put(skb, len);
1994                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1995
1996         } else {
1997                 /* Uncompressed frame - pass to decompressor so it
1998                    can update its dictionary if necessary. */
1999                 if (ppp->rcomp->incomp)
2000                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2001                                            skb->len + 2);
2002         }
2003
2004         return skb;
2005
2006  err:
2007         ppp->rstate |= SC_DC_ERROR;
2008         ppp_receive_error(ppp);
2009         return skb;
2010 }
2011
2012 #ifdef CONFIG_PPP_MULTILINK
2013 /*
2014  * Receive a multilink frame.
2015  * We put it on the reconstruction queue and then pull off
2016  * as many completed frames as we can.
2017  */
2018 static void
2019 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2020 {
2021         u32 mask, seq;
2022         struct channel *ch;
2023         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2024
2025         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2026                 goto err;               /* no good, throw it away */
2027
2028         /* Decode sequence number and begin/end bits */
2029         if (ppp->flags & SC_MP_SHORTSEQ) {
2030                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2031                 mask = 0xfff;
2032         } else {
2033                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2034                 mask = 0xffffff;
2035         }
2036         PPP_MP_CB(skb)->BEbits = skb->data[2];
2037         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2038
2039         /*
2040          * Do protocol ID decompression on the first fragment of each packet.
2041          */
2042         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2043                 *skb_push(skb, 1) = 0;
2044
2045         /*
2046          * Expand sequence number to 32 bits, making it as close
2047          * as possible to ppp->minseq.
2048          */
2049         seq |= ppp->minseq & ~mask;
2050         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2051                 seq += mask + 1;
2052         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2053                 seq -= mask + 1;        /* should never happen */
2054         PPP_MP_CB(skb)->sequence = seq;
2055         pch->lastseq = seq;
2056
2057         /*
2058          * If this packet comes before the next one we were expecting,
2059          * drop it.
2060          */
2061         if (seq_before(seq, ppp->nextseq)) {
2062                 kfree_skb(skb);
2063                 ++ppp->dev->stats.rx_dropped;
2064                 ppp_receive_error(ppp);
2065                 return;
2066         }
2067
2068         /*
2069          * Reevaluate minseq, the minimum over all channels of the
2070          * last sequence number received on each channel.  Because of
2071          * the increasing sequence number rule, we know that any fragment
2072          * before `minseq' which hasn't arrived is never going to arrive.
2073          * The list of channels can't change because we have the receive
2074          * side of the ppp unit locked.
2075          */
2076         list_for_each_entry(ch, &ppp->channels, clist) {
2077                 if (seq_before(ch->lastseq, seq))
2078                         seq = ch->lastseq;
2079         }
2080         if (seq_before(ppp->minseq, seq))
2081                 ppp->minseq = seq;
2082
2083         /* Put the fragment on the reconstruction queue */
2084         ppp_mp_insert(ppp, skb);
2085
2086         /* If the queue is getting long, don't wait any longer for packets
2087            before the start of the queue. */
2088         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2089                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2090                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2091                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2092         }
2093
2094         /* Pull completed packets off the queue and receive them. */
2095         while ((skb = ppp_mp_reconstruct(ppp))) {
2096                 if (pskb_may_pull(skb, 2))
2097                         ppp_receive_nonmp_frame(ppp, skb);
2098                 else {
2099                         ++ppp->dev->stats.rx_length_errors;
2100                         kfree_skb(skb);
2101                         ppp_receive_error(ppp);
2102                 }
2103         }
2104
2105         return;
2106
2107  err:
2108         kfree_skb(skb);
2109         ppp_receive_error(ppp);
2110 }
2111
2112 /*
2113  * Insert a fragment on the MP reconstruction queue.
2114  * The queue is ordered by increasing sequence number.
2115  */
2116 static void
2117 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2118 {
2119         struct sk_buff *p;
2120         struct sk_buff_head *list = &ppp->mrq;
2121         u32 seq = PPP_MP_CB(skb)->sequence;
2122
2123         /* N.B. we don't need to lock the list lock because we have the
2124            ppp unit receive-side lock. */
2125         skb_queue_walk(list, p) {
2126                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2127                         break;
2128         }
2129         __skb_queue_before(list, p, skb);
2130 }
2131
2132 /*
2133  * Reconstruct a packet from the MP fragment queue.
2134  * We go through increasing sequence numbers until we find a
2135  * complete packet, or we get to the sequence number for a fragment
2136  * which hasn't arrived but might still do so.
2137  */
2138 static struct sk_buff *
2139 ppp_mp_reconstruct(struct ppp *ppp)
2140 {
2141         u32 seq = ppp->nextseq;
2142         u32 minseq = ppp->minseq;
2143         struct sk_buff_head *list = &ppp->mrq;
2144         struct sk_buff *p, *tmp;
2145         struct sk_buff *head, *tail;
2146         struct sk_buff *skb = NULL;
2147         int lost = 0, len = 0;
2148
2149         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2150                 return NULL;
2151         head = list->next;
2152         tail = NULL;
2153         skb_queue_walk_safe(list, p, tmp) {
2154         again:
2155                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2156                         /* this can't happen, anyway ignore the skb */
2157                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2158                                    "seq %u < %u\n",
2159                                    PPP_MP_CB(p)->sequence, seq);
2160                         __skb_unlink(p, list);
2161                         kfree_skb(p);
2162                         continue;
2163                 }
2164                 if (PPP_MP_CB(p)->sequence != seq) {
2165                         u32 oldseq;
2166                         /* Fragment `seq' is missing.  If it is after
2167                            minseq, it might arrive later, so stop here. */
2168                         if (seq_after(seq, minseq))
2169                                 break;
2170                         /* Fragment `seq' is lost, keep going. */
2171                         lost = 1;
2172                         oldseq = seq;
2173                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2174                                 minseq + 1: PPP_MP_CB(p)->sequence;
2175
2176                         if (ppp->debug & 1)
2177                                 netdev_printk(KERN_DEBUG, ppp->dev,
2178                                               "lost frag %u..%u\n",
2179                                               oldseq, seq-1);
2180
2181                         goto again;
2182                 }
2183
2184                 /*
2185                  * At this point we know that all the fragments from
2186                  * ppp->nextseq to seq are either present or lost.
2187                  * Also, there are no complete packets in the queue
2188                  * that have no missing fragments and end before this
2189                  * fragment.
2190                  */
2191
2192                 /* B bit set indicates this fragment starts a packet */
2193                 if (PPP_MP_CB(p)->BEbits & B) {
2194                         head = p;
2195                         lost = 0;
2196                         len = 0;
2197                 }
2198
2199                 len += p->len;
2200
2201                 /* Got a complete packet yet? */
2202                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2203                     (PPP_MP_CB(head)->BEbits & B)) {
2204                         if (len > ppp->mrru + 2) {
2205                                 ++ppp->dev->stats.rx_length_errors;
2206                                 netdev_printk(KERN_DEBUG, ppp->dev,
2207                                               "PPP: reconstructed packet"
2208                                               " is too long (%d)\n", len);
2209                         } else {
2210                                 tail = p;
2211                                 break;
2212                         }
2213                         ppp->nextseq = seq + 1;
2214                 }
2215
2216                 /*
2217                  * If this is the ending fragment of a packet,
2218                  * and we haven't found a complete valid packet yet,
2219                  * we can discard up to and including this fragment.
2220                  */
2221                 if (PPP_MP_CB(p)->BEbits & E) {
2222                         struct sk_buff *tmp2;
2223
2224                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2225                                 if (ppp->debug & 1)
2226                                         netdev_printk(KERN_DEBUG, ppp->dev,
2227                                                       "discarding frag %u\n",
2228                                                       PPP_MP_CB(p)->sequence);
2229                                 __skb_unlink(p, list);
2230                                 kfree_skb(p);
2231                         }
2232                         head = skb_peek(list);
2233                         if (!head)
2234                                 break;
2235                 }
2236                 ++seq;
2237         }
2238
2239         /* If we have a complete packet, copy it all into one skb. */
2240         if (tail != NULL) {
2241                 /* If we have discarded any fragments,
2242                    signal a receive error. */
2243                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2244                         skb_queue_walk_safe(list, p, tmp) {
2245                                 if (p == head)
2246                                         break;
2247                                 if (ppp->debug & 1)
2248                                         netdev_printk(KERN_DEBUG, ppp->dev,
2249                                                       "discarding frag %u\n",
2250                                                       PPP_MP_CB(p)->sequence);
2251                                 __skb_unlink(p, list);
2252                                 kfree_skb(p);
2253                         }
2254
2255                         if (ppp->debug & 1)
2256                                 netdev_printk(KERN_DEBUG, ppp->dev,
2257                                               "  missed pkts %u..%u\n",
2258                                               ppp->nextseq,
2259                                               PPP_MP_CB(head)->sequence-1);
2260                         ++ppp->dev->stats.rx_dropped;
2261                         ppp_receive_error(ppp);
2262                 }
2263
2264                 skb = head;
2265                 if (head != tail) {
2266                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2267                         p = skb_queue_next(list, head);
2268                         __skb_unlink(skb, list);
2269                         skb_queue_walk_from_safe(list, p, tmp) {
2270                                 __skb_unlink(p, list);
2271                                 *fragpp = p;
2272                                 p->next = NULL;
2273                                 fragpp = &p->next;
2274
2275                                 skb->len += p->len;
2276                                 skb->data_len += p->len;
2277                                 skb->truesize += p->truesize;
2278
2279                                 if (p == tail)
2280                                         break;
2281                         }
2282                 } else {
2283                         __skb_unlink(skb, list);
2284                 }
2285
2286                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2287         }
2288
2289         return skb;
2290 }
2291 #endif /* CONFIG_PPP_MULTILINK */
2292
2293 /*
2294  * Channel interface.
2295  */
2296
2297 /* Create a new, unattached ppp channel. */
2298 int ppp_register_channel(struct ppp_channel *chan)
2299 {
2300         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2301 }
2302
2303 /* Create a new, unattached ppp channel for specified net. */
2304 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2305 {
2306         struct channel *pch;
2307         struct ppp_net *pn;
2308
2309         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2310         if (!pch)
2311                 return -ENOMEM;
2312
2313         pn = ppp_pernet(net);
2314
2315         pch->ppp = NULL;
2316         pch->chan = chan;
2317         pch->chan_net = get_net(net);
2318         chan->ppp = pch;
2319         init_ppp_file(&pch->file, CHANNEL);
2320         pch->file.hdrlen = chan->hdrlen;
2321 #ifdef CONFIG_PPP_MULTILINK
2322         pch->lastseq = -1;
2323 #endif /* CONFIG_PPP_MULTILINK */
2324         init_rwsem(&pch->chan_sem);
2325         spin_lock_init(&pch->downl);
2326         rwlock_init(&pch->upl);
2327
2328         spin_lock_bh(&pn->all_channels_lock);
2329         pch->file.index = ++pn->last_channel_index;
2330         list_add(&pch->list, &pn->new_channels);
2331         atomic_inc(&channel_count);
2332         spin_unlock_bh(&pn->all_channels_lock);
2333
2334         return 0;
2335 }
2336
2337 /*
2338  * Return the index of a channel.
2339  */
2340 int ppp_channel_index(struct ppp_channel *chan)
2341 {
2342         struct channel *pch = chan->ppp;
2343
2344         if (pch)
2345                 return pch->file.index;
2346         return -1;
2347 }
2348
2349 /*
2350  * Return the PPP unit number to which a channel is connected.
2351  */
2352 int ppp_unit_number(struct ppp_channel *chan)
2353 {
2354         struct channel *pch = chan->ppp;
2355         int unit = -1;
2356
2357         if (pch) {
2358                 read_lock_bh(&pch->upl);
2359                 if (pch->ppp)
2360                         unit = pch->ppp->file.index;
2361                 read_unlock_bh(&pch->upl);
2362         }
2363         return unit;
2364 }
2365
2366 /*
2367  * Return the PPP device interface name of a channel.
2368  */
2369 char *ppp_dev_name(struct ppp_channel *chan)
2370 {
2371         struct channel *pch = chan->ppp;
2372         char *name = NULL;
2373
2374         if (pch) {
2375                 read_lock_bh(&pch->upl);
2376                 if (pch->ppp && pch->ppp->dev)
2377                         name = pch->ppp->dev->name;
2378                 read_unlock_bh(&pch->upl);
2379         }
2380         return name;
2381 }
2382
2383
2384 /*
2385  * Disconnect a channel from the generic layer.
2386  * This must be called in process context.
2387  */
2388 void
2389 ppp_unregister_channel(struct ppp_channel *chan)
2390 {
2391         struct channel *pch = chan->ppp;
2392         struct ppp_net *pn;
2393
2394         if (!pch)
2395                 return;         /* should never happen */
2396
2397         chan->ppp = NULL;
2398
2399         /*
2400          * This ensures that we have returned from any calls into the
2401          * the channel's start_xmit or ioctl routine before we proceed.
2402          */
2403         down_write(&pch->chan_sem);
2404         spin_lock_bh(&pch->downl);
2405         pch->chan = NULL;
2406         spin_unlock_bh(&pch->downl);
2407         up_write(&pch->chan_sem);
2408         ppp_disconnect_channel(pch);
2409
2410         pn = ppp_pernet(pch->chan_net);
2411         spin_lock_bh(&pn->all_channels_lock);
2412         list_del(&pch->list);
2413         spin_unlock_bh(&pn->all_channels_lock);
2414
2415         pch->file.dead = 1;
2416         wake_up_interruptible(&pch->file.rwait);
2417         if (atomic_dec_and_test(&pch->file.refcnt))
2418                 ppp_destroy_channel(pch);
2419 }
2420
2421 /*
2422  * Callback from a channel when it can accept more to transmit.
2423  * This should be called at BH/softirq level, not interrupt level.
2424  */
2425 void
2426 ppp_output_wakeup(struct ppp_channel *chan)
2427 {
2428         struct channel *pch = chan->ppp;
2429
2430         if (!pch)
2431                 return;
2432         ppp_channel_push(pch);
2433 }
2434
2435 /*
2436  * Compression control.
2437  */
2438
2439 /* Process the PPPIOCSCOMPRESS ioctl. */
2440 static int
2441 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2442 {
2443         int err;
2444         struct compressor *cp, *ocomp;
2445         struct ppp_option_data data;
2446         void *state, *ostate;
2447         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2448
2449         err = -EFAULT;
2450         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2451             (data.length <= CCP_MAX_OPTION_LENGTH &&
2452              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2453                 goto out;
2454         err = -EINVAL;
2455         if (data.length > CCP_MAX_OPTION_LENGTH ||
2456             ccp_option[1] < 2 || ccp_option[1] > data.length)
2457                 goto out;
2458
2459         cp = try_then_request_module(
2460                 find_compressor(ccp_option[0]),
2461                 "ppp-compress-%d", ccp_option[0]);
2462         if (!cp)
2463                 goto out;
2464
2465         err = -ENOBUFS;
2466         if (data.transmit) {
2467                 state = cp->comp_alloc(ccp_option, data.length);
2468                 if (state) {
2469                         ppp_xmit_lock(ppp);
2470                         ppp->xstate &= ~SC_COMP_RUN;
2471                         ocomp = ppp->xcomp;
2472                         ostate = ppp->xc_state;
2473                         ppp->xcomp = cp;
2474                         ppp->xc_state = state;
2475                         ppp_xmit_unlock(ppp);
2476                         if (ostate) {
2477                                 ocomp->comp_free(ostate);
2478                                 module_put(ocomp->owner);
2479                         }
2480                         err = 0;
2481                 } else
2482                         module_put(cp->owner);
2483
2484         } else {
2485                 state = cp->decomp_alloc(ccp_option, data.length);
2486                 if (state) {
2487                         ppp_recv_lock(ppp);
2488                         ppp->rstate &= ~SC_DECOMP_RUN;
2489                         ocomp = ppp->rcomp;
2490                         ostate = ppp->rc_state;
2491                         ppp->rcomp = cp;
2492                         ppp->rc_state = state;
2493                         ppp_recv_unlock(ppp);
2494                         if (ostate) {
2495                                 ocomp->decomp_free(ostate);
2496                                 module_put(ocomp->owner);
2497                         }
2498                         err = 0;
2499                 } else
2500                         module_put(cp->owner);
2501         }
2502
2503  out:
2504         return err;
2505 }
2506
2507 /*
2508  * Look at a CCP packet and update our state accordingly.
2509  * We assume the caller has the xmit or recv path locked.
2510  */
2511 static void
2512 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2513 {
2514         unsigned char *dp;
2515         int len;
2516
2517         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2518                 return; /* no header */
2519         dp = skb->data + 2;
2520
2521         switch (CCP_CODE(dp)) {
2522         case CCP_CONFREQ:
2523
2524                 /* A ConfReq starts negotiation of compression
2525                  * in one direction of transmission,
2526                  * and hence brings it down...but which way?
2527                  *
2528                  * Remember:
2529                  * A ConfReq indicates what the sender would like to receive
2530                  */
2531                 if(inbound)
2532                         /* He is proposing what I should send */
2533                         ppp->xstate &= ~SC_COMP_RUN;
2534                 else
2535                         /* I am proposing to what he should send */
2536                         ppp->rstate &= ~SC_DECOMP_RUN;
2537
2538                 break;
2539
2540         case CCP_TERMREQ:
2541         case CCP_TERMACK:
2542                 /*
2543                  * CCP is going down, both directions of transmission
2544                  */
2545                 ppp->rstate &= ~SC_DECOMP_RUN;
2546                 ppp->xstate &= ~SC_COMP_RUN;
2547                 break;
2548
2549         case CCP_CONFACK:
2550                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2551                         break;
2552                 len = CCP_LENGTH(dp);
2553                 if (!pskb_may_pull(skb, len + 2))
2554                         return;         /* too short */
2555                 dp += CCP_HDRLEN;
2556                 len -= CCP_HDRLEN;
2557                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2558                         break;
2559                 if (inbound) {
2560                         /* we will start receiving compressed packets */
2561                         if (!ppp->rc_state)
2562                                 break;
2563                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2564                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2565                                 ppp->rstate |= SC_DECOMP_RUN;
2566                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2567                         }
2568                 } else {
2569                         /* we will soon start sending compressed packets */
2570                         if (!ppp->xc_state)
2571                                 break;
2572                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2573                                         ppp->file.index, 0, ppp->debug))
2574                                 ppp->xstate |= SC_COMP_RUN;
2575                 }
2576                 break;
2577
2578         case CCP_RESETACK:
2579                 /* reset the [de]compressor */
2580                 if ((ppp->flags & SC_CCP_UP) == 0)
2581                         break;
2582                 if (inbound) {
2583                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2584                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2585                                 ppp->rstate &= ~SC_DC_ERROR;
2586                         }
2587                 } else {
2588                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2589                                 ppp->xcomp->comp_reset(ppp->xc_state);
2590                 }
2591                 break;
2592         }
2593 }
2594
2595 /* Free up compression resources. */
2596 static void
2597 ppp_ccp_closed(struct ppp *ppp)
2598 {
2599         void *xstate, *rstate;
2600         struct compressor *xcomp, *rcomp;
2601
2602         ppp_lock(ppp);
2603         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2604         ppp->xstate = 0;
2605         xcomp = ppp->xcomp;
2606         xstate = ppp->xc_state;
2607         ppp->xc_state = NULL;
2608         ppp->rstate = 0;
2609         rcomp = ppp->rcomp;
2610         rstate = ppp->rc_state;
2611         ppp->rc_state = NULL;
2612         ppp_unlock(ppp);
2613
2614         if (xstate) {
2615                 xcomp->comp_free(xstate);
2616                 module_put(xcomp->owner);
2617         }
2618         if (rstate) {
2619                 rcomp->decomp_free(rstate);
2620                 module_put(rcomp->owner);
2621         }
2622 }
2623
2624 /* List of compressors. */
2625 static LIST_HEAD(compressor_list);
2626 static DEFINE_SPINLOCK(compressor_list_lock);
2627
2628 struct compressor_entry {
2629         struct list_head list;
2630         struct compressor *comp;
2631 };
2632
2633 static struct compressor_entry *
2634 find_comp_entry(int proto)
2635 {
2636         struct compressor_entry *ce;
2637
2638         list_for_each_entry(ce, &compressor_list, list) {
2639                 if (ce->comp->compress_proto == proto)
2640                         return ce;
2641         }
2642         return NULL;
2643 }
2644
2645 /* Register a compressor */
2646 int
2647 ppp_register_compressor(struct compressor *cp)
2648 {
2649         struct compressor_entry *ce;
2650         int ret;
2651         spin_lock(&compressor_list_lock);
2652         ret = -EEXIST;
2653         if (find_comp_entry(cp->compress_proto))
2654                 goto out;
2655         ret = -ENOMEM;
2656         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2657         if (!ce)
2658                 goto out;
2659         ret = 0;
2660         ce->comp = cp;
2661         list_add(&ce->list, &compressor_list);
2662  out:
2663         spin_unlock(&compressor_list_lock);
2664         return ret;
2665 }
2666
2667 /* Unregister a compressor */
2668 void
2669 ppp_unregister_compressor(struct compressor *cp)
2670 {
2671         struct compressor_entry *ce;
2672
2673         spin_lock(&compressor_list_lock);
2674         ce = find_comp_entry(cp->compress_proto);
2675         if (ce && ce->comp == cp) {
2676                 list_del(&ce->list);
2677                 kfree(ce);
2678         }
2679         spin_unlock(&compressor_list_lock);
2680 }
2681
2682 /* Find a compressor. */
2683 static struct compressor *
2684 find_compressor(int type)
2685 {
2686         struct compressor_entry *ce;
2687         struct compressor *cp = NULL;
2688
2689         spin_lock(&compressor_list_lock);
2690         ce = find_comp_entry(type);
2691         if (ce) {
2692                 cp = ce->comp;
2693                 if (!try_module_get(cp->owner))
2694                         cp = NULL;
2695         }
2696         spin_unlock(&compressor_list_lock);
2697         return cp;
2698 }
2699
2700 /*
2701  * Miscelleneous stuff.
2702  */
2703
2704 static void
2705 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2706 {
2707         struct slcompress *vj = ppp->vj;
2708
2709         memset(st, 0, sizeof(*st));
2710         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2711         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2712         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2713         st->p.ppp_opackets = ppp->stats64.tx_packets;
2714         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2715         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2716         if (!vj)
2717                 return;
2718         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2719         st->vj.vjs_compressed = vj->sls_o_compressed;
2720         st->vj.vjs_searches = vj->sls_o_searches;
2721         st->vj.vjs_misses = vj->sls_o_misses;
2722         st->vj.vjs_errorin = vj->sls_i_error;
2723         st->vj.vjs_tossed = vj->sls_i_tossed;
2724         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2725         st->vj.vjs_compressedin = vj->sls_i_compressed;
2726 }
2727
2728 /*
2729  * Stuff for handling the lists of ppp units and channels
2730  * and for initialization.
2731  */
2732
2733 /*
2734  * Create a new ppp interface unit.  Fails if it can't allocate memory
2735  * or if there is already a unit with the requested number.
2736  * unit == -1 means allocate a new number.
2737  */
2738 static struct ppp *ppp_create_interface(struct net *net, int unit,
2739                                         struct file *file, int *retp)
2740 {
2741         struct ppp *ppp;
2742         struct ppp_net *pn;
2743         struct net_device *dev = NULL;
2744         int ret = -ENOMEM;
2745         int i;
2746
2747         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_UNKNOWN,
2748                            ppp_setup);
2749         if (!dev)
2750                 goto out1;
2751
2752         pn = ppp_pernet(net);
2753
2754         ppp = netdev_priv(dev);
2755         ppp->dev = dev;
2756         ppp->mru = PPP_MRU;
2757         init_ppp_file(&ppp->file, INTERFACE);
2758         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2759         ppp->owner = file;
2760         for (i = 0; i < NUM_NP; ++i)
2761                 ppp->npmode[i] = NPMODE_PASS;
2762         INIT_LIST_HEAD(&ppp->channels);
2763         spin_lock_init(&ppp->rlock);
2764         spin_lock_init(&ppp->wlock);
2765 #ifdef CONFIG_PPP_MULTILINK
2766         ppp->minseq = -1;
2767         skb_queue_head_init(&ppp->mrq);
2768 #endif /* CONFIG_PPP_MULTILINK */
2769 #ifdef CONFIG_PPP_FILTER
2770         ppp->pass_filter = NULL;
2771         ppp->active_filter = NULL;
2772 #endif /* CONFIG_PPP_FILTER */
2773
2774         /*
2775          * drum roll: don't forget to set
2776          * the net device is belong to
2777          */
2778         dev_net_set(dev, net);
2779
2780         rtnl_lock();
2781         mutex_lock(&pn->all_ppp_mutex);
2782
2783         if (unit < 0) {
2784                 unit = unit_get(&pn->units_idr, ppp);
2785                 if (unit < 0) {
2786                         ret = unit;
2787                         goto out2;
2788                 }
2789         } else {
2790                 ret = -EEXIST;
2791                 if (unit_find(&pn->units_idr, unit))
2792                         goto out2; /* unit already exists */
2793                 /*
2794                  * if caller need a specified unit number
2795                  * lets try to satisfy him, otherwise --
2796                  * he should better ask us for new unit number
2797                  *
2798                  * NOTE: yes I know that returning EEXIST it's not
2799                  * fair but at least pppd will ask us to allocate
2800                  * new unit in this case so user is happy :)
2801                  */
2802                 unit = unit_set(&pn->units_idr, ppp, unit);
2803                 if (unit < 0)
2804                         goto out2;
2805         }
2806
2807         /* Initialize the new ppp unit */
2808         ppp->file.index = unit;
2809         sprintf(dev->name, "ppp%d", unit);
2810
2811         ret = register_netdevice(dev);
2812         if (ret != 0) {
2813                 unit_put(&pn->units_idr, unit);
2814                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2815                            dev->name, ret);
2816                 goto out2;
2817         }
2818
2819         ppp->ppp_net = net;
2820
2821         atomic_inc(&ppp_unit_count);
2822         mutex_unlock(&pn->all_ppp_mutex);
2823         rtnl_unlock();
2824
2825         *retp = 0;
2826         return ppp;
2827
2828 out2:
2829         mutex_unlock(&pn->all_ppp_mutex);
2830         rtnl_unlock();
2831         free_netdev(dev);
2832 out1:
2833         *retp = ret;
2834         return NULL;
2835 }
2836
2837 /*
2838  * Initialize a ppp_file structure.
2839  */
2840 static void
2841 init_ppp_file(struct ppp_file *pf, int kind)
2842 {
2843         pf->kind = kind;
2844         skb_queue_head_init(&pf->xq);
2845         skb_queue_head_init(&pf->rq);
2846         atomic_set(&pf->refcnt, 1);
2847         init_waitqueue_head(&pf->rwait);
2848 }
2849
2850 /*
2851  * Free the memory used by a ppp unit.  This is only called once
2852  * there are no channels connected to the unit and no file structs
2853  * that reference the unit.
2854  */
2855 static void ppp_destroy_interface(struct ppp *ppp)
2856 {
2857         atomic_dec(&ppp_unit_count);
2858
2859         if (!ppp->file.dead || ppp->n_channels) {
2860                 /* "can't happen" */
2861                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2862                            "but dead=%d n_channels=%d !\n",
2863                            ppp, ppp->file.dead, ppp->n_channels);
2864                 return;
2865         }
2866
2867         ppp_ccp_closed(ppp);
2868         if (ppp->vj) {
2869                 slhc_free(ppp->vj);
2870                 ppp->vj = NULL;
2871         }
2872         skb_queue_purge(&ppp->file.xq);
2873         skb_queue_purge(&ppp->file.rq);
2874 #ifdef CONFIG_PPP_MULTILINK
2875         skb_queue_purge(&ppp->mrq);
2876 #endif /* CONFIG_PPP_MULTILINK */
2877 #ifdef CONFIG_PPP_FILTER
2878         if (ppp->pass_filter) {
2879                 bpf_prog_destroy(ppp->pass_filter);
2880                 ppp->pass_filter = NULL;
2881         }
2882
2883         if (ppp->active_filter) {
2884                 bpf_prog_destroy(ppp->active_filter);
2885                 ppp->active_filter = NULL;
2886         }
2887 #endif /* CONFIG_PPP_FILTER */
2888
2889         kfree_skb(ppp->xmit_pending);
2890
2891         free_netdev(ppp->dev);
2892 }
2893
2894 /*
2895  * Locate an existing ppp unit.
2896  * The caller should have locked the all_ppp_mutex.
2897  */
2898 static struct ppp *
2899 ppp_find_unit(struct ppp_net *pn, int unit)
2900 {
2901         return unit_find(&pn->units_idr, unit);
2902 }
2903
2904 /*
2905  * Locate an existing ppp channel.
2906  * The caller should have locked the all_channels_lock.
2907  * First we look in the new_channels list, then in the
2908  * all_channels list.  If found in the new_channels list,
2909  * we move it to the all_channels list.  This is for speed
2910  * when we have a lot of channels in use.
2911  */
2912 static struct channel *
2913 ppp_find_channel(struct ppp_net *pn, int unit)
2914 {
2915         struct channel *pch;
2916
2917         list_for_each_entry(pch, &pn->new_channels, list) {
2918                 if (pch->file.index == unit) {
2919                         list_move(&pch->list, &pn->all_channels);
2920                         return pch;
2921                 }
2922         }
2923
2924         list_for_each_entry(pch, &pn->all_channels, list) {
2925                 if (pch->file.index == unit)
2926                         return pch;
2927         }
2928
2929         return NULL;
2930 }
2931
2932 /*
2933  * Connect a PPP channel to a PPP interface unit.
2934  */
2935 static int
2936 ppp_connect_channel(struct channel *pch, int unit)
2937 {
2938         struct ppp *ppp;
2939         struct ppp_net *pn;
2940         int ret = -ENXIO;
2941         int hdrlen;
2942
2943         pn = ppp_pernet(pch->chan_net);
2944
2945         mutex_lock(&pn->all_ppp_mutex);
2946         ppp = ppp_find_unit(pn, unit);
2947         if (!ppp)
2948                 goto out;
2949         write_lock_bh(&pch->upl);
2950         ret = -EINVAL;
2951         if (pch->ppp)
2952                 goto outl;
2953
2954         ppp_lock(ppp);
2955         spin_lock_bh(&pch->downl);
2956         if (!pch->chan) {
2957                 /* Don't connect unregistered channels */
2958                 spin_unlock_bh(&pch->downl);
2959                 ppp_unlock(ppp);
2960                 ret = -ENOTCONN;
2961                 goto outl;
2962         }
2963         spin_unlock_bh(&pch->downl);
2964         if (pch->file.hdrlen > ppp->file.hdrlen)
2965                 ppp->file.hdrlen = pch->file.hdrlen;
2966         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2967         if (hdrlen > ppp->dev->hard_header_len)
2968                 ppp->dev->hard_header_len = hdrlen;
2969         list_add_tail(&pch->clist, &ppp->channels);
2970         ++ppp->n_channels;
2971         pch->ppp = ppp;
2972         atomic_inc(&ppp->file.refcnt);
2973         ppp_unlock(ppp);
2974         ret = 0;
2975
2976  outl:
2977         write_unlock_bh(&pch->upl);
2978  out:
2979         mutex_unlock(&pn->all_ppp_mutex);
2980         return ret;
2981 }
2982
2983 /*
2984  * Disconnect a channel from its ppp unit.
2985  */
2986 static int
2987 ppp_disconnect_channel(struct channel *pch)
2988 {
2989         struct ppp *ppp;
2990         int err = -EINVAL;
2991
2992         write_lock_bh(&pch->upl);
2993         ppp = pch->ppp;
2994         pch->ppp = NULL;
2995         write_unlock_bh(&pch->upl);
2996         if (ppp) {
2997                 /* remove it from the ppp unit's list */
2998                 ppp_lock(ppp);
2999                 list_del(&pch->clist);
3000                 if (--ppp->n_channels == 0)
3001                         wake_up_interruptible(&ppp->file.rwait);
3002                 ppp_unlock(ppp);
3003                 if (atomic_dec_and_test(&ppp->file.refcnt))
3004                         ppp_destroy_interface(ppp);
3005                 err = 0;
3006         }
3007         return err;
3008 }
3009
3010 /*
3011  * Free up the resources used by a ppp channel.
3012  */
3013 static void ppp_destroy_channel(struct channel *pch)
3014 {
3015         put_net(pch->chan_net);
3016         pch->chan_net = NULL;
3017
3018         atomic_dec(&channel_count);
3019
3020         if (!pch->file.dead) {
3021                 /* "can't happen" */
3022                 pr_err("ppp: destroying undead channel %p !\n", pch);
3023                 return;
3024         }
3025         skb_queue_purge(&pch->file.xq);
3026         skb_queue_purge(&pch->file.rq);
3027         kfree(pch);
3028 }
3029
3030 static void __exit ppp_cleanup(void)
3031 {
3032         /* should never happen */
3033         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3034                 pr_err("PPP: removing module but units remain!\n");
3035         unregister_chrdev(PPP_MAJOR, "ppp");
3036         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3037         class_destroy(ppp_class);
3038         unregister_pernet_device(&ppp_net_ops);
3039 }
3040
3041 /*
3042  * Units handling. Caller must protect concurrent access
3043  * by holding all_ppp_mutex
3044  */
3045
3046 /* associate pointer with specified number */
3047 static int unit_set(struct idr *p, void *ptr, int n)
3048 {
3049         int unit;
3050
3051         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3052         if (unit == -ENOSPC)
3053                 unit = -EINVAL;
3054         return unit;
3055 }
3056
3057 /* get new free unit number and associate pointer with it */
3058 static int unit_get(struct idr *p, void *ptr)
3059 {
3060         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3061 }
3062
3063 /* put unit number back to a pool */
3064 static void unit_put(struct idr *p, int n)
3065 {
3066         idr_remove(p, n);
3067 }
3068
3069 /* get pointer associated with the number */
3070 static void *unit_find(struct idr *p, int n)
3071 {
3072         return idr_find(p, n);
3073 }
3074
3075 /* Module/initialization stuff */
3076
3077 module_init(ppp_init);
3078 module_exit(ppp_cleanup);
3079
3080 EXPORT_SYMBOL(ppp_register_net_channel);
3081 EXPORT_SYMBOL(ppp_register_channel);
3082 EXPORT_SYMBOL(ppp_unregister_channel);
3083 EXPORT_SYMBOL(ppp_channel_index);
3084 EXPORT_SYMBOL(ppp_unit_number);
3085 EXPORT_SYMBOL(ppp_dev_name);
3086 EXPORT_SYMBOL(ppp_input);
3087 EXPORT_SYMBOL(ppp_input_error);
3088 EXPORT_SYMBOL(ppp_output_wakeup);
3089 EXPORT_SYMBOL(ppp_register_compressor);
3090 EXPORT_SYMBOL(ppp_unregister_compressor);
3091 MODULE_LICENSE("GPL");
3092 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3093 MODULE_ALIAS("devname:ppp");