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
 447                         ppp_recv_lock(ppp);
 448                         if (ppp->n_channels == 0 &&
 449                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 450                                 ppp_recv_unlock(ppp);
 451                                 break;
 452                         }
 453                         ppp_recv_unlock(ppp);
 454                 }
 455                 ret = -EAGAIN;
 456                 if (file->f_flags & O_NONBLOCK)
 457                         break;
 458                 ret = -ERESTARTSYS;
 459                 if (signal_pending(current))
 460                         break;
 461                 schedule();
 462         }
 463         set_current_state(TASK_RUNNING);
 464         remove_wait_queue(&pf->rwait, &wait);
 465
 466         if (!skb)
 467                 goto out;
 468
 469         ret = -EOVERFLOW;
 470         if (skb->len > count)
 471                 goto outf;
 472         ret = -EFAULT;
 473         iov.iov_base = buf;
 474         iov.iov_len = count;
 475         iov_iter_init(&to, READ, &iov, 1, count);
 476         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 477                 goto outf;
 478         ret = skb->len;
 479
 480  outf:
 481         kfree_skb(skb);
 482  out:
 483         return ret;
 484 }
 485
 486 static ssize_t ppp_write(struct file *file, const char __user *buf,
 487                          size_t count, loff_t *ppos)
 488 {
 489         struct ppp_file *pf = file->private_data;
 490         struct sk_buff *skb;
 491         ssize_t ret;
 492
 493         if (!pf)
 494                 return -ENXIO;
 495         ret = -ENOMEM;
 496         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 497         if (!skb)
 498                 goto out;
 499         skb_reserve(skb, pf->hdrlen);
 500         ret = -EFAULT;
 501         if (copy_from_user(skb_put(skb, count), buf, count)) {
 502                 kfree_skb(skb);
 503                 goto out;
 504         }
 505
 506         skb_queue_tail(&pf->xq, skb);
 507
 508         switch (pf->kind) {
 509         case INTERFACE:
 510                 ppp_xmit_process(PF_TO_PPP(pf));
 511                 break;
 512         case CHANNEL:
 513                 ppp_channel_push(PF_TO_CHANNEL(pf));
 514                 break;
 515         }
 516
 517         ret = count;
 518
 519  out:
 520         return ret;
 521 }
 522
 523 /* No kernel lock - fine */
 524 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 525 {
 526         struct ppp_file *pf = file->private_data;
 527         unsigned int mask;
 528
 529         if (!pf)
 530                 return 0;
 531         poll_wait(file, &pf->rwait, wait);
 532         mask = POLLOUT | POLLWRNORM;
 533         if (skb_peek(&pf->rq))
 534                 mask |= POLLIN | POLLRDNORM;
 535         if (pf->dead)
 536                 mask |= POLLHUP;
 537         else if (pf->kind == INTERFACE) {
 538                 /* see comment in ppp_read */
 539                 struct ppp *ppp = PF_TO_PPP(pf);
 540
 541                 ppp_recv_lock(ppp);
 542                 if (ppp->n_channels == 0 &&
 543                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 544                         mask |= POLLIN | POLLRDNORM;
 545                 ppp_recv_unlock(ppp);
 546         }
 547
 548         return mask;
 549 }
 550
 551 #ifdef CONFIG_PPP_FILTER
 552 static int get_filter(void __user *arg, struct sock_filter **p)
 553 {
 554         struct sock_fprog uprog;
 555         struct sock_filter *code = NULL;
 556         int len;
 557
 558         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 559                 return -EFAULT;
 560
 561         if (!uprog.len) {
 562                 *p = NULL;
 563                 return 0;
 564         }
 565
 566         len = uprog.len * sizeof(struct sock_filter);
 567         code = memdup_user(uprog.filter, len);
 568         if (IS_ERR(code))
 569                 return PTR_ERR(code);
 570
 571         *p = code;
 572         return uprog.len;
 573 }
 574 #endif /* CONFIG_PPP_FILTER */
 575
 576 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 577 {
 578         struct ppp_file *pf;
 579         struct ppp *ppp;
 580         int err = -EFAULT, val, val2, i;
 581         struct ppp_idle idle;
 582         struct npioctl npi;
 583         int unit, cflags;
 584         struct slcompress *vj;
 585         void __user *argp = (void __user *)arg;
 586         int __user *p = argp;
 587
 588         mutex_lock(&ppp_mutex);
 589
 590         pf = file->private_data;
 591         if (!pf) {
 592                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 593                                            pf, file, cmd, arg);
 594                 goto out;
 595         }
 596
 597         if (cmd == PPPIOCDETACH) {
 598                 /*
 599                  * We have to be careful here... if the file descriptor
 600                  * has been dup'd, we could have another process in the
 601                  * middle of a poll using the same file *, so we had
 602                  * better not free the interface data structures -
 603                  * instead we fail the ioctl.  Even in this case, we
 604                  * shut down the interface if we are the owner of it.
 605                  * Actually, we should get rid of PPPIOCDETACH, userland
 606                  * (i.e. pppd) could achieve the same effect by closing
 607                  * this fd and reopening /dev/ppp.
 608                  */
 609                 err = -EINVAL;
 610                 if (pf->kind == INTERFACE) {
 611                         ppp = PF_TO_PPP(pf);
 612                         rtnl_lock();
 613                         if (file == ppp->owner)
 614                                 unregister_netdevice(ppp->dev);
 615                         rtnl_unlock();
 616                 }
 617                 if (atomic_long_read(&file->f_count) < 2) {
 618                         ppp_release(NULL, file);
 619                         err = 0;
 620                 } else
 621                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 622                                 atomic_long_read(&file->f_count));
 623                 goto out;
 624         }
 625
 626         if (pf->kind == CHANNEL) {
 627                 struct channel *pch;
 628                 struct ppp_channel *chan;
 629
 630                 pch = PF_TO_CHANNEL(pf);
 631
 632                 switch (cmd) {
 633                 case PPPIOCCONNECT:
 634                         if (get_user(unit, p))
 635                                 break;
 636                         err = ppp_connect_channel(pch, unit);
 637                         break;
 638
 639                 case PPPIOCDISCONN:
 640                         err = ppp_disconnect_channel(pch);
 641                         break;
 642
 643                 default:
 644                         down_read(&pch->chan_sem);
 645                         chan = pch->chan;
 646                         err = -ENOTTY;
 647                         if (chan && chan->ops->ioctl)
 648                                 err = chan->ops->ioctl(chan, cmd, arg);
 649                         up_read(&pch->chan_sem);
 650                 }
 651                 goto out;
 652         }
 653
 654         if (pf->kind != INTERFACE) {
 655                 /* can't happen */
 656                 pr_err("PPP: not interface or channel??\n");
 657                 err = -EINVAL;
 658                 goto out;
 659         }
 660
 661         ppp = PF_TO_PPP(pf);
 662         switch (cmd) {
 663         case PPPIOCSMRU:
 664                 if (get_user(val, p))
 665                         break;
 666                 ppp->mru = val;
 667                 err = 0;
 668                 break;
 669
 670         case PPPIOCSFLAGS:
 671                 if (get_user(val, p))
 672                         break;
 673                 ppp_lock(ppp);
 674                 cflags = ppp->flags & ~val;
 675 #ifdef CONFIG_PPP_MULTILINK
 676                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 677                         ppp->nextseq = 0;
 678 #endif
 679                 ppp->flags = val & SC_FLAG_BITS;
 680                 ppp_unlock(ppp);
 681                 if (cflags & SC_CCP_OPEN)
 682                         ppp_ccp_closed(ppp);
 683                 err = 0;
 684                 break;
 685
 686         case PPPIOCGFLAGS:
 687                 val = ppp->flags | ppp->xstate | ppp->rstate;
 688                 if (put_user(val, p))
 689                         break;
 690                 err = 0;
 691                 break;
 692
 693         case PPPIOCSCOMPRESS:
 694                 err = ppp_set_compress(ppp, arg);
 695                 break;
 696
 697         case PPPIOCGUNIT:
 698                 if (put_user(ppp->file.index, p))
 699                         break;
 700                 err = 0;
 701                 break;
 702
 703         case PPPIOCSDEBUG:
 704                 if (get_user(val, p))
 705                         break;
 706                 ppp->debug = val;
 707                 err = 0;
 708                 break;
 709
 710         case PPPIOCGDEBUG:
 711                 if (put_user(ppp->debug, p))
 712                         break;
 713                 err = 0;
 714                 break;
 715
 716         case PPPIOCGIDLE:
 717                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 718                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 719                 if (copy_to_user(argp, &idle, sizeof(idle)))
 720                         break;
 721                 err = 0;
 722                 break;
 723
 724         case PPPIOCSMAXCID:
 725                 if (get_user(val, p))
 726                         break;
 727                 val2 = 15;
 728                 if ((val >> 16) != 0) {
 729                         val2 = val >> 16;
 730                         val &= 0xffff;
 731                 }
 732                 vj = slhc_init(val2+1, val+1);
 733                 if (IS_ERR(vj)) {
 734                         err = PTR_ERR(vj);
 735                         break;
 736                 }
 737                 ppp_lock(ppp);
 738                 if (ppp->vj)
 739                         slhc_free(ppp->vj);
 740                 ppp->vj = vj;
 741                 ppp_unlock(ppp);
 742                 err = 0;
 743                 break;
 744
 745         case PPPIOCGNPMODE:
 746         case PPPIOCSNPMODE:
 747                 if (copy_from_user(&npi, argp, sizeof(npi)))
 748                         break;
 749                 err = proto_to_npindex(npi.protocol);
 750                 if (err < 0)
 751                         break;
 752                 i = err;
 753                 if (cmd == PPPIOCGNPMODE) {
 754                         err = -EFAULT;
 755                         npi.mode = ppp->npmode[i];
 756                         if (copy_to_user(argp, &npi, sizeof(npi)))
 757                                 break;
 758                 } else {
 759                         ppp->npmode[i] = npi.mode;
 760                         /* we may be able to transmit more packets now (??) */
 761                         netif_wake_queue(ppp->dev);
 762                 }
 763                 err = 0;
 764                 break;
 765
 766 #ifdef CONFIG_PPP_FILTER
 767         case PPPIOCSPASS:
 768         {
 769                 struct sock_filter *code;
 770
 771                 err = get_filter(argp, &code);
 772                 if (err >= 0) {
 773                         struct bpf_prog *pass_filter = NULL;
 774                         struct sock_fprog_kern fprog = {
 775                                 .len = err,
 776                                 .filter = code,
 777                         };
 778
 779                         err = 0;
 780                         if (fprog.filter)
 781                                 err = bpf_prog_create(&pass_filter, &fprog);
 782                         if (!err) {
 783                                 ppp_lock(ppp);
 784                                 if (ppp->pass_filter)
 785                                         bpf_prog_destroy(ppp->pass_filter);
 786                                 ppp->pass_filter = pass_filter;
 787                                 ppp_unlock(ppp);
 788                         }
 789                         kfree(code);
 790                 }
 791                 break;
 792         }
 793         case PPPIOCSACTIVE:
 794         {
 795                 struct sock_filter *code;
 796
 797                 err = get_filter(argp, &code);
 798                 if (err >= 0) {
 799                         struct bpf_prog *active_filter = NULL;
 800                         struct sock_fprog_kern fprog = {
 801                                 .len = err,
 802                                 .filter = code,
 803                         };
 804
 805                         err = 0;
 806                         if (fprog.filter)
 807                                 err = bpf_prog_create(&active_filter, &fprog);
 808                         if (!err) {
 809                                 ppp_lock(ppp);
 810                                 if (ppp->active_filter)
 811                                         bpf_prog_destroy(ppp->active_filter);
 812                                 ppp->active_filter = active_filter;
 813                                 ppp_unlock(ppp);
 814                         }
 815                         kfree(code);
 816                 }
 817                 break;
 818         }
 819 #endif /* CONFIG_PPP_FILTER */
 820
 821 #ifdef CONFIG_PPP_MULTILINK
 822         case PPPIOCSMRRU:
 823                 if (get_user(val, p))
 824                         break;
 825                 ppp_recv_lock(ppp);
 826                 ppp->mrru = val;
 827                 ppp_recv_unlock(ppp);
 828                 err = 0;
 829                 break;
 830 #endif /* CONFIG_PPP_MULTILINK */
 831
 832         default:
 833                 err = -ENOTTY;
 834         }
 835
 836 out:
 837         mutex_unlock(&ppp_mutex);
 838
 839         return err;
 840 }
 841
 842 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 843                         struct file *file, unsigned int cmd, unsigned long arg)
 844 {
 845         int unit, err = -EFAULT;
 846         struct ppp *ppp;
 847         struct channel *chan;
 848         struct ppp_net *pn;
 849         int __user *p = (int __user *)arg;
 850
 851         switch (cmd) {
 852         case PPPIOCNEWUNIT:
 853                 /* Create a new ppp unit */
 854                 if (get_user(unit, p))
 855                         break;
 856                 ppp = ppp_create_interface(net, unit, file, &err);
 857                 if (!ppp)
 858                         break;
 859                 file->private_data = &ppp->file;
 860                 err = -EFAULT;
 861                 if (put_user(ppp->file.index, p))
 862                         break;
 863                 err = 0;
 864                 break;
 865
 866         case PPPIOCATTACH:
 867                 /* Attach to an existing ppp unit */
 868                 if (get_user(unit, p))
 869                         break;
 870                 err = -ENXIO;
 871                 pn = ppp_pernet(net);
 872                 mutex_lock(&pn->all_ppp_mutex);
 873                 ppp = ppp_find_unit(pn, unit);
 874                 if (ppp) {
 875                         atomic_inc(&ppp->file.refcnt);
 876                         file->private_data = &ppp->file;
 877                         err = 0;
 878                 }
 879                 mutex_unlock(&pn->all_ppp_mutex);
 880                 break;
 881
 882         case PPPIOCATTCHAN:
 883                 if (get_user(unit, p))
 884                         break;
 885                 err = -ENXIO;
 886                 pn = ppp_pernet(net);
 887                 spin_lock_bh(&pn->all_channels_lock);
 888                 chan = ppp_find_channel(pn, unit);
 889                 if (chan) {
 890                         atomic_inc(&chan->file.refcnt);
 891                         file->private_data = &chan->file;
 892                         err = 0;
 893                 }
 894                 spin_unlock_bh(&pn->all_channels_lock);
 895                 break;
 896
 897         default:
 898                 err = -ENOTTY;
 899         }
 900
 901         return err;
 902 }
 903
 904 static const struct file_operations ppp_device_fops = {
 905         .owner          = THIS_MODULE,
 906         .read           = ppp_read,
 907         .write          = ppp_write,
 908         .poll           = ppp_poll,
 909         .unlocked_ioctl = ppp_ioctl,
 910         .open           = ppp_open,
 911         .release        = ppp_release,
 912         .llseek         = noop_llseek,
 913 };
 914
 915 static __net_init int ppp_init_net(struct net *net)
 916 {
 917         struct ppp_net *pn = net_generic(net, ppp_net_id);
 918
 919         idr_init(&pn->units_idr);
 920         mutex_init(&pn->all_ppp_mutex);
 921
 922         INIT_LIST_HEAD(&pn->all_channels);
 923         INIT_LIST_HEAD(&pn->new_channels);
 924
 925         spin_lock_init(&pn->all_channels_lock);
 926
 927         return 0;
 928 }
 929
 930 static __net_exit void ppp_exit_net(struct net *net)
 931 {
 932         struct ppp_net *pn = net_generic(net, ppp_net_id);
 933         struct net_device *dev;
 934         struct net_device *aux;
 935         struct ppp *ppp;
 936         LIST_HEAD(list);
 937         int id;
 938
 939         rtnl_lock();
 940         for_each_netdev_safe(net, dev, aux) {
 941                 if (dev->netdev_ops == &ppp_netdev_ops)
 942                         unregister_netdevice_queue(dev, &list);
 943         }
 944
 945         idr_for_each_entry(&pn->units_idr, ppp, id)
 946                 /* Skip devices already unregistered by previous loop */
 947                 if (!net_eq(dev_net(ppp->dev), net))
 948                         unregister_netdevice_queue(ppp->dev, &list);
 949
 950         unregister_netdevice_many(&list);
 951         rtnl_unlock();
 952
 953         idr_destroy(&pn->units_idr);
 954 }
 955
 956 static struct pernet_operations ppp_net_ops = {
 957         .init = ppp_init_net,
 958         .exit = ppp_exit_net,
 959         .id   = &ppp_net_id,
 960         .size = sizeof(struct ppp_net),
 961 };
 962
 963 #define PPP_MAJOR       108
 964
 965 /* Called at boot time if ppp is compiled into the kernel,
 966    or at module load time (from init_module) if compiled as a module. */
 967 static int __init ppp_init(void)
 968 {
 969         int err;
 970
 971         pr_info("PPP generic driver version " PPP_VERSION "\n");
 972
 973         err = register_pernet_device(&ppp_net_ops);
 974         if (err) {
 975                 pr_err("failed to register PPP pernet device (%d)\n", err);
 976                 goto out;
 977         }
 978
 979         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 980         if (err) {
 981                 pr_err("failed to register PPP device (%d)\n", err);
 982                 goto out_net;
 983         }
 984
 985         ppp_class = class_create(THIS_MODULE, "ppp");
 986         if (IS_ERR(ppp_class)) {
 987                 err = PTR_ERR(ppp_class);
 988                 goto out_chrdev;
 989         }
 990
 991         /* not a big deal if we fail here :-) */
 992         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 993
 994         return 0;
 995
 996 out_chrdev:
 997         unregister_chrdev(PPP_MAJOR, "ppp");
 998 out_net:
 999         unregister_pernet_device(&ppp_net_ops);
1000 out:
1001         return err;
1002 }
1003
1004 /*
1005  * Network interface unit routines.
1006  */
1007 static netdev_tx_t
1008 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1009 {
1010         struct ppp *ppp = netdev_priv(dev);
1011         int npi, proto;
1012         unsigned char *pp;
1013
1014         npi = ethertype_to_npindex(ntohs(skb->protocol));
1015         if (npi < 0)
1016                 goto outf;
1017
1018         /* Drop, accept or reject the packet */
1019         switch (ppp->npmode[npi]) {
1020         case NPMODE_PASS:
1021                 break;
1022         case NPMODE_QUEUE:
1023                 /* it would be nice to have a way to tell the network
1024                    system to queue this one up for later. */
1025                 goto outf;
1026         case NPMODE_DROP:
1027         case NPMODE_ERROR:
1028                 goto outf;
1029         }
1030
1031         /* Put the 2-byte PPP protocol number on the front,
1032            making sure there is room for the address and control fields. */
1033         if (skb_cow_head(skb, PPP_HDRLEN))
1034                 goto outf;
1035
1036         pp = skb_push(skb, 2);
1037         proto = npindex_to_proto[npi];
1038         put_unaligned_be16(proto, pp);
1039
1040         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1041         skb_queue_tail(&ppp->file.xq, skb);
1042         ppp_xmit_process(ppp);
1043         return NETDEV_TX_OK;
1044
1045  outf:
1046         kfree_skb(skb);
1047         ++dev->stats.tx_dropped;
1048         return NETDEV_TX_OK;
1049 }
1050
1051 static int
1052 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1053 {
1054         struct ppp *ppp = netdev_priv(dev);
1055         int err = -EFAULT;
1056         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1057         struct ppp_stats stats;
1058         struct ppp_comp_stats cstats;
1059         char *vers;
1060
1061         switch (cmd) {
1062         case SIOCGPPPSTATS:
1063                 ppp_get_stats(ppp, &stats);
1064                 if (copy_to_user(addr, &stats, sizeof(stats)))
1065                         break;
1066                 err = 0;
1067                 break;
1068
1069         case SIOCGPPPCSTATS:
1070                 memset(&cstats, 0, sizeof(cstats));
1071                 if (ppp->xc_state)
1072                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1073                 if (ppp->rc_state)
1074                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1075                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1076                         break;
1077                 err = 0;
1078                 break;
1079
1080         case SIOCGPPPVER:
1081                 vers = PPP_VERSION;
1082                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1083                         break;
1084                 err = 0;
1085                 break;
1086
1087         default:
1088                 err = -EINVAL;
1089         }
1090
1091         return err;
1092 }
1093
1094 static struct rtnl_link_stats64*
1095 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1096 {
1097         struct ppp *ppp = netdev_priv(dev);
1098
1099         ppp_recv_lock(ppp);
1100         stats64->rx_packets = ppp->stats64.rx_packets;
1101         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1102         ppp_recv_unlock(ppp);
1103
1104         ppp_xmit_lock(ppp);
1105         stats64->tx_packets = ppp->stats64.tx_packets;
1106         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1107         ppp_xmit_unlock(ppp);
1108
1109         stats64->rx_errors        = dev->stats.rx_errors;
1110         stats64->tx_errors        = dev->stats.tx_errors;
1111         stats64->rx_dropped       = dev->stats.rx_dropped;
1112         stats64->tx_dropped       = dev->stats.tx_dropped;
1113         stats64->rx_length_errors = dev->stats.rx_length_errors;
1114
1115         return stats64;
1116 }
1117
1118 static struct lock_class_key ppp_tx_busylock;
1119 static int ppp_dev_init(struct net_device *dev)
1120 {
1121         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1122         return 0;
1123 }
1124
1125 static void ppp_dev_uninit(struct net_device *dev)
1126 {
1127         struct ppp *ppp = netdev_priv(dev);
1128         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1129
1130         ppp_lock(ppp);
1131         ppp->closing = 1;
1132         ppp_unlock(ppp);
1133
1134         mutex_lock(&pn->all_ppp_mutex);
1135         unit_put(&pn->units_idr, ppp->file.index);
1136         mutex_unlock(&pn->all_ppp_mutex);
1137
1138         ppp->owner = NULL;
1139
1140         ppp->file.dead = 1;
1141         wake_up_interruptible(&ppp->file.rwait);
1142 }
1143
1144 static const struct net_device_ops ppp_netdev_ops = {
1145         .ndo_init        = ppp_dev_init,
1146         .ndo_uninit      = ppp_dev_uninit,
1147         .ndo_start_xmit  = ppp_start_xmit,
1148         .ndo_do_ioctl    = ppp_net_ioctl,
1149         .ndo_get_stats64 = ppp_get_stats64,
1150 };
1151
1152 static struct device_type ppp_type = {
1153         .name = "ppp",
1154 };
1155
1156 static void ppp_setup(struct net_device *dev)
1157 {
1158         dev->netdev_ops = &ppp_netdev_ops;
1159         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1160
1161         dev->hard_header_len = PPP_HDRLEN;
1162         dev->mtu = PPP_MRU;
1163         dev->addr_len = 0;
1164         dev->tx_queue_len = 3;
1165         dev->type = ARPHRD_PPP;
1166         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1167         netif_keep_dst(dev);
1168 }
1169
1170 /*
1171  * Transmit-side routines.
1172  */
1173
1174 /*
1175  * Called to do any work queued up on the transmit side
1176  * that can now be done.
1177  */
1178 static void
1179 ppp_xmit_process(struct ppp *ppp)
1180 {
1181         struct sk_buff *skb;
1182
1183         ppp_xmit_lock(ppp);
1184         if (!ppp->closing) {
1185                 ppp_push(ppp);
1186                 while (!ppp->xmit_pending &&
1187                        (skb = skb_dequeue(&ppp->file.xq)))
1188                         ppp_send_frame(ppp, skb);
1189                 /* If there's no work left to do, tell the core net
1190                    code that we can accept some more. */
1191                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1192                         netif_wake_queue(ppp->dev);
1193                 else
1194                         netif_stop_queue(ppp->dev);
1195         }
1196         ppp_xmit_unlock(ppp);
1197 }
1198
1199 static inline struct sk_buff *
1200 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1201 {
1202         struct sk_buff *new_skb;
1203         int len;
1204         int new_skb_size = ppp->dev->mtu +
1205                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1206         int compressor_skb_size = ppp->dev->mtu +
1207                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1208         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1209         if (!new_skb) {
1210                 if (net_ratelimit())
1211                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1212                 return NULL;
1213         }
1214         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1215                 skb_reserve(new_skb,
1216                             ppp->dev->hard_header_len - PPP_HDRLEN);
1217
1218         /* compressor still expects A/C bytes in hdr */
1219         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1220                                    new_skb->data, skb->len + 2,
1221                                    compressor_skb_size);
1222         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1223                 consume_skb(skb);
1224                 skb = new_skb;
1225                 skb_put(skb, len);
1226                 skb_pull(skb, 2);       /* pull off A/C bytes */
1227         } else if (len == 0) {
1228                 /* didn't compress, or CCP not up yet */
1229                 consume_skb(new_skb);
1230                 new_skb = skb;
1231         } else {
1232                 /*
1233                  * (len < 0)
1234                  * MPPE requires that we do not send unencrypted
1235                  * frames.  The compressor will return -1 if we
1236                  * should drop the frame.  We cannot simply test
1237                  * the compress_proto because MPPE and MPPC share
1238                  * the same number.
1239                  */
1240                 if (net_ratelimit())
1241                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1242                 kfree_skb(skb);
1243                 consume_skb(new_skb);
1244                 new_skb = NULL;
1245         }
1246         return new_skb;
1247 }
1248
1249 /*
1250  * Compress and send a frame.
1251  * The caller should have locked the xmit path,
1252  * and xmit_pending should be 0.
1253  */
1254 static void
1255 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1256 {
1257         int proto = PPP_PROTO(skb);
1258         struct sk_buff *new_skb;
1259         int len;
1260         unsigned char *cp;
1261
1262         if (proto < 0x8000) {
1263 #ifdef CONFIG_PPP_FILTER
1264                 /* check if we should pass this packet */
1265                 /* the filter instructions are constructed assuming
1266                    a four-byte PPP header on each packet */
1267                 *skb_push(skb, 2) = 1;
1268                 if (ppp->pass_filter &&
1269                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1270                         if (ppp->debug & 1)
1271                                 netdev_printk(KERN_DEBUG, ppp->dev,
1272                                               "PPP: outbound frame "
1273                                               "not passed\n");
1274                         kfree_skb(skb);
1275                         return;
1276                 }
1277                 /* if this packet passes the active filter, record the time */
1278                 if (!(ppp->active_filter &&
1279                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1280                         ppp->last_xmit = jiffies;
1281                 skb_pull(skb, 2);
1282 #else
1283                 /* for data packets, record the time */
1284                 ppp->last_xmit = jiffies;
1285 #endif /* CONFIG_PPP_FILTER */
1286         }
1287
1288         ++ppp->stats64.tx_packets;
1289         ppp->stats64.tx_bytes += skb->len - 2;
1290
1291         switch (proto) {
1292         case PPP_IP:
1293                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1294                         break;
1295                 /* try to do VJ TCP header compression */
1296                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1297                                     GFP_ATOMIC);
1298                 if (!new_skb) {
1299                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1300                         goto drop;
1301                 }
1302                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1303                 cp = skb->data + 2;
1304                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1305                                     new_skb->data + 2, &cp,
1306                                     !(ppp->flags & SC_NO_TCP_CCID));
1307                 if (cp == skb->data + 2) {
1308                         /* didn't compress */
1309                         consume_skb(new_skb);
1310                 } else {
1311                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1312                                 proto = PPP_VJC_COMP;
1313                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1314                         } else {
1315                                 proto = PPP_VJC_UNCOMP;
1316                                 cp[0] = skb->data[2];
1317                         }
1318                         consume_skb(skb);
1319                         skb = new_skb;
1320                         cp = skb_put(skb, len + 2);
1321                         cp[0] = 0;
1322                         cp[1] = proto;
1323                 }
1324                 break;
1325
1326         case PPP_CCP:
1327                 /* peek at outbound CCP frames */
1328                 ppp_ccp_peek(ppp, skb, 0);
1329                 break;
1330         }
1331
1332         /* try to do packet compression */
1333         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1334             proto != PPP_LCP && proto != PPP_CCP) {
1335                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1336                         if (net_ratelimit())
1337                                 netdev_err(ppp->dev,
1338                                            "ppp: compression required but "
1339                                            "down - pkt dropped.\n");
1340                         goto drop;
1341                 }
1342                 skb = pad_compress_skb(ppp, skb);
1343                 if (!skb)
1344                         goto drop;
1345         }
1346
1347         /*
1348          * If we are waiting for traffic (demand dialling),
1349          * queue it up for pppd to receive.
1350          */
1351         if (ppp->flags & SC_LOOP_TRAFFIC) {
1352                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1353                         goto drop;
1354                 skb_queue_tail(&ppp->file.rq, skb);
1355                 wake_up_interruptible(&ppp->file.rwait);
1356                 return;
1357         }
1358
1359         ppp->xmit_pending = skb;
1360         ppp_push(ppp);
1361         return;
1362
1363  drop:
1364         kfree_skb(skb);
1365         ++ppp->dev->stats.tx_errors;
1366 }
1367
1368 /*
1369  * Try to send the frame in xmit_pending.
1370  * The caller should have the xmit path locked.
1371  */
1372 static void
1373 ppp_push(struct ppp *ppp)
1374 {
1375         struct list_head *list;
1376         struct channel *pch;
1377         struct sk_buff *skb = ppp->xmit_pending;
1378
1379         if (!skb)
1380                 return;
1381
1382         list = &ppp->channels;
1383         if (list_empty(list)) {
1384                 /* nowhere to send the packet, just drop it */
1385                 ppp->xmit_pending = NULL;
1386                 kfree_skb(skb);
1387                 return;
1388         }
1389
1390         if ((ppp->flags & SC_MULTILINK) == 0) {
1391                 /* not doing multilink: send it down the first channel */
1392                 list = list->next;
1393                 pch = list_entry(list, struct channel, clist);
1394
1395                 spin_lock_bh(&pch->downl);
1396                 if (pch->chan) {
1397                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1398                                 ppp->xmit_pending = NULL;
1399                 } else {
1400                         /* channel got unregistered */
1401                         kfree_skb(skb);
1402                         ppp->xmit_pending = NULL;
1403                 }
1404                 spin_unlock_bh(&pch->downl);
1405                 return;
1406         }
1407
1408 #ifdef CONFIG_PPP_MULTILINK
1409         /* Multilink: fragment the packet over as many links
1410            as can take the packet at the moment. */
1411         if (!ppp_mp_explode(ppp, skb))
1412                 return;
1413 #endif /* CONFIG_PPP_MULTILINK */
1414
1415         ppp->xmit_pending = NULL;
1416         kfree_skb(skb);
1417 }
1418
1419 #ifdef CONFIG_PPP_MULTILINK
1420 static bool mp_protocol_compress __read_mostly = true;
1421 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1422 MODULE_PARM_DESC(mp_protocol_compress,
1423                  "compress protocol id in multilink fragments");
1424
1425 /*
1426  * Divide a packet to be transmitted into fragments and
1427  * send them out the individual links.
1428  */
1429 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1430 {
1431         int len, totlen;
1432         int i, bits, hdrlen, mtu;
1433         int flen;
1434         int navail, nfree, nzero;
1435         int nbigger;
1436         int totspeed;
1437         int totfree;
1438         unsigned char *p, *q;
1439         struct list_head *list;
1440         struct channel *pch;
1441         struct sk_buff *frag;
1442         struct ppp_channel *chan;
1443
1444         totspeed = 0; /*total bitrate of the bundle*/
1445         nfree = 0; /* # channels which have no packet already queued */
1446         navail = 0; /* total # of usable channels (not deregistered) */
1447         nzero = 0; /* number of channels with zero speed associated*/
1448         totfree = 0; /*total # of channels available and
1449                                   *having no queued packets before
1450                                   *starting the fragmentation*/
1451
1452         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1453         i = 0;
1454         list_for_each_entry(pch, &ppp->channels, clist) {
1455                 if (pch->chan) {
1456                         pch->avail = 1;
1457                         navail++;
1458                         pch->speed = pch->chan->speed;
1459                 } else {
1460                         pch->avail = 0;
1461                 }
1462                 if (pch->avail) {
1463                         if (skb_queue_empty(&pch->file.xq) ||
1464                                 !pch->had_frag) {
1465                                         if (pch->speed == 0)
1466                                                 nzero++;
1467                                         else
1468                                                 totspeed += pch->speed;
1469
1470                                         pch->avail = 2;
1471                                         ++nfree;
1472                                         ++totfree;
1473                                 }
1474                         if (!pch->had_frag && i < ppp->nxchan)
1475                                 ppp->nxchan = i;
1476                 }
1477                 ++i;
1478         }
1479         /*
1480          * Don't start sending this packet unless at least half of
1481          * the channels are free.  This gives much better TCP
1482          * performance if we have a lot of channels.
1483          */
1484         if (nfree == 0 || nfree < navail / 2)
1485                 return 0; /* can't take now, leave it in xmit_pending */
1486
1487         /* Do protocol field compression */
1488         p = skb->data;
1489         len = skb->len;
1490         if (*p == 0 && mp_protocol_compress) {
1491                 ++p;
1492                 --len;
1493         }
1494
1495         totlen = len;
1496         nbigger = len % nfree;
1497
1498         /* skip to the channel after the one we last used
1499            and start at that one */
1500         list = &ppp->channels;
1501         for (i = 0; i < ppp->nxchan; ++i) {
1502                 list = list->next;
1503                 if (list == &ppp->channels) {
1504                         i = 0;
1505                         break;
1506                 }
1507         }
1508
1509         /* create a fragment for each channel */
1510         bits = B;
1511         while (len > 0) {
1512                 list = list->next;
1513                 if (list == &ppp->channels) {
1514                         i = 0;
1515                         continue;
1516                 }
1517                 pch = list_entry(list, struct channel, clist);
1518                 ++i;
1519                 if (!pch->avail)
1520                         continue;
1521
1522                 /*
1523                  * Skip this channel if it has a fragment pending already and
1524                  * we haven't given a fragment to all of the free channels.
1525                  */
1526                 if (pch->avail == 1) {
1527                         if (nfree > 0)
1528                                 continue;
1529                 } else {
1530                         pch->avail = 1;
1531                 }
1532
1533                 /* check the channel's mtu and whether it is still attached. */
1534                 spin_lock_bh(&pch->downl);
1535                 if (pch->chan == NULL) {
1536                         /* can't use this channel, it's being deregistered */
1537                         if (pch->speed == 0)
1538                                 nzero--;
1539                         else
1540                                 totspeed -= pch->speed;
1541
1542                         spin_unlock_bh(&pch->downl);
1543                         pch->avail = 0;
1544                         totlen = len;
1545                         totfree--;
1546                         nfree--;
1547                         if (--navail == 0)
1548                                 break;
1549                         continue;
1550                 }
1551
1552                 /*
1553                 *if the channel speed is not set divide
1554                 *the packet evenly among the free channels;
1555                 *otherwise divide it according to the speed
1556                 *of the channel we are going to transmit on
1557                 */
1558                 flen = len;
1559                 if (nfree > 0) {
1560                         if (pch->speed == 0) {
1561                                 flen = len/nfree;
1562                                 if (nbigger > 0) {
1563                                         flen++;
1564                                         nbigger--;
1565                                 }
1566                         } else {
1567                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1568                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1569                                 if (nbigger > 0) {
1570                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1571                                         nbigger -= ((totfree - nzero)*pch->speed)/
1572                                                         totspeed;
1573                                 }
1574                         }
1575                         nfree--;
1576                 }
1577
1578                 /*
1579                  *check if we are on the last channel or
1580                  *we exceded the length of the data to
1581                  *fragment
1582                  */
1583                 if ((nfree <= 0) || (flen > len))
1584                         flen = len;
1585                 /*
1586                  *it is not worth to tx on slow channels:
1587                  *in that case from the resulting flen according to the
1588                  *above formula will be equal or less than zero.
1589                  *Skip the channel in this case
1590                  */
1591                 if (flen <= 0) {
1592                         pch->avail = 2;
1593                         spin_unlock_bh(&pch->downl);
1594                         continue;
1595                 }
1596
1597                 /*
1598                  * hdrlen includes the 2-byte PPP protocol field, but the
1599                  * MTU counts only the payload excluding the protocol field.
1600                  * (RFC1661 Section 2)
1601                  */
1602                 mtu = pch->chan->mtu - (hdrlen - 2);
1603                 if (mtu < 4)
1604                         mtu = 4;
1605                 if (flen > mtu)
1606                         flen = mtu;
1607                 if (flen == len)
1608                         bits |= E;
1609                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1610                 if (!frag)
1611                         goto noskb;
1612                 q = skb_put(frag, flen + hdrlen);
1613
1614                 /* make the MP header */
1615                 put_unaligned_be16(PPP_MP, q);
1616                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1617                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1618                         q[3] = ppp->nxseq;
1619                 } else {
1620                         q[2] = bits;
1621                         q[3] = ppp->nxseq >> 16;
1622                         q[4] = ppp->nxseq >> 8;
1623                         q[5] = ppp->nxseq;
1624                 }
1625
1626                 memcpy(q + hdrlen, p, flen);
1627
1628                 /* try to send it down the channel */
1629                 chan = pch->chan;
1630                 if (!skb_queue_empty(&pch->file.xq) ||
1631                         !chan->ops->start_xmit(chan, frag))
1632                         skb_queue_tail(&pch->file.xq, frag);
1633                 pch->had_frag = 1;
1634                 p += flen;
1635                 len -= flen;
1636                 ++ppp->nxseq;
1637                 bits = 0;
1638                 spin_unlock_bh(&pch->downl);
1639         }
1640         ppp->nxchan = i;
1641
1642         return 1;
1643
1644  noskb:
1645         spin_unlock_bh(&pch->downl);
1646         if (ppp->debug & 1)
1647                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1648         ++ppp->dev->stats.tx_errors;
1649         ++ppp->nxseq;
1650         return 1;       /* abandon the frame */
1651 }
1652 #endif /* CONFIG_PPP_MULTILINK */
1653
1654 /*
1655  * Try to send data out on a channel.
1656  */
1657 static void
1658 ppp_channel_push(struct channel *pch)
1659 {
1660         struct sk_buff *skb;
1661         struct ppp *ppp;
1662
1663         spin_lock_bh(&pch->downl);
1664         if (pch->chan) {
1665                 while (!skb_queue_empty(&pch->file.xq)) {
1666                         skb = skb_dequeue(&pch->file.xq);
1667                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1668                                 /* put the packet back and try again later */
1669                                 skb_queue_head(&pch->file.xq, skb);
1670                                 break;
1671                         }
1672                 }
1673         } else {
1674                 /* channel got deregistered */
1675                 skb_queue_purge(&pch->file.xq);
1676         }
1677         spin_unlock_bh(&pch->downl);
1678         /* see if there is anything from the attached unit to be sent */
1679         if (skb_queue_empty(&pch->file.xq)) {
1680                 read_lock_bh(&pch->upl);
1681                 ppp = pch->ppp;
1682                 if (ppp)
1683                         ppp_xmit_process(ppp);
1684                 read_unlock_bh(&pch->upl);
1685         }
1686 }
1687
1688 /*
1689  * Receive-side routines.
1690  */
1691
1692 struct ppp_mp_skb_parm {
1693         u32             sequence;
1694         u8              BEbits;
1695 };
1696 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1697
1698 static inline void
1699 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1700 {
1701         ppp_recv_lock(ppp);
1702         if (!ppp->closing)
1703                 ppp_receive_frame(ppp, skb, pch);
1704         else
1705                 kfree_skb(skb);
1706         ppp_recv_unlock(ppp);
1707 }
1708
1709 void
1710 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1711 {
1712         struct channel *pch = chan->ppp;
1713         int proto;
1714
1715         if (!pch) {
1716                 kfree_skb(skb);
1717                 return;
1718         }
1719
1720         read_lock_bh(&pch->upl);
1721         if (!pskb_may_pull(skb, 2)) {
1722                 kfree_skb(skb);
1723                 if (pch->ppp) {
1724                         ++pch->ppp->dev->stats.rx_length_errors;
1725                         ppp_receive_error(pch->ppp);
1726                 }
1727                 goto done;
1728         }
1729
1730         proto = PPP_PROTO(skb);
1731         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1732                 /* put it on the channel queue */
1733                 skb_queue_tail(&pch->file.rq, skb);
1734                 /* drop old frames if queue too long */
1735                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1736                        (skb = skb_dequeue(&pch->file.rq)))
1737                         kfree_skb(skb);
1738                 wake_up_interruptible(&pch->file.rwait);
1739         } else {
1740                 ppp_do_recv(pch->ppp, skb, pch);
1741         }
1742
1743 done:
1744         read_unlock_bh(&pch->upl);
1745 }
1746
1747 /* Put a 0-length skb in the receive queue as an error indication */
1748 void
1749 ppp_input_error(struct ppp_channel *chan, int code)
1750 {
1751         struct channel *pch = chan->ppp;
1752         struct sk_buff *skb;
1753
1754         if (!pch)
1755                 return;
1756
1757         read_lock_bh(&pch->upl);
1758         if (pch->ppp) {
1759                 skb = alloc_skb(0, GFP_ATOMIC);
1760                 if (skb) {
1761                         skb->len = 0;           /* probably unnecessary */
1762                         skb->cb[0] = code;
1763                         ppp_do_recv(pch->ppp, skb, pch);
1764                 }
1765         }
1766         read_unlock_bh(&pch->upl);
1767 }
1768
1769 /*
1770  * We come in here to process a received frame.
1771  * The receive side of the ppp unit is locked.
1772  */
1773 static void
1774 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1775 {
1776         /* note: a 0-length skb is used as an error indication */
1777         if (skb->len > 0) {
1778                 skb_checksum_complete_unset(skb);
1779 #ifdef CONFIG_PPP_MULTILINK
1780                 /* XXX do channel-level decompression here */
1781                 if (PPP_PROTO(skb) == PPP_MP)
1782                         ppp_receive_mp_frame(ppp, skb, pch);
1783                 else
1784 #endif /* CONFIG_PPP_MULTILINK */
1785                         ppp_receive_nonmp_frame(ppp, skb);
1786         } else {
1787                 kfree_skb(skb);
1788                 ppp_receive_error(ppp);
1789         }
1790 }
1791
1792 static void
1793 ppp_receive_error(struct ppp *ppp)
1794 {
1795         ++ppp->dev->stats.rx_errors;
1796         if (ppp->vj)
1797                 slhc_toss(ppp->vj);
1798 }
1799
1800 static void
1801 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1802 {
1803         struct sk_buff *ns;
1804         int proto, len, npi;
1805
1806         /*
1807          * Decompress the frame, if compressed.
1808          * Note that some decompressors need to see uncompressed frames
1809          * that come in as well as compressed frames.
1810          */
1811         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1812             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1813                 skb = ppp_decompress_frame(ppp, skb);
1814
1815         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1816                 goto err;
1817
1818         proto = PPP_PROTO(skb);
1819         switch (proto) {
1820         case PPP_VJC_COMP:
1821                 /* decompress VJ compressed packets */
1822                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1823                         goto err;
1824
1825                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1826                         /* copy to a new sk_buff with more tailroom */
1827                         ns = dev_alloc_skb(skb->len + 128);
1828                         if (!ns) {
1829                                 netdev_err(ppp->dev, "PPP: no memory "
1830                                            "(VJ decomp)\n");
1831                                 goto err;
1832                         }
1833                         skb_reserve(ns, 2);
1834                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1835                         consume_skb(skb);
1836                         skb = ns;
1837                 }
1838                 else
1839                         skb->ip_summed = CHECKSUM_NONE;
1840
1841                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1842                 if (len <= 0) {
1843                         netdev_printk(KERN_DEBUG, ppp->dev,
1844                                       "PPP: VJ decompression error\n");
1845                         goto err;
1846                 }
1847                 len += 2;
1848                 if (len > skb->len)
1849                         skb_put(skb, len - skb->len);
1850                 else if (len < skb->len)
1851                         skb_trim(skb, len);
1852                 proto = PPP_IP;
1853                 break;
1854
1855         case PPP_VJC_UNCOMP:
1856                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1857                         goto err;
1858
1859                 /* Until we fix the decompressor need to make sure
1860                  * data portion is linear.
1861                  */
1862                 if (!pskb_may_pull(skb, skb->len))
1863                         goto err;
1864
1865                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1866                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1867                         goto err;
1868                 }
1869                 proto = PPP_IP;
1870                 break;
1871
1872         case PPP_CCP:
1873                 ppp_ccp_peek(ppp, skb, 1);
1874                 break;
1875         }
1876
1877         ++ppp->stats64.rx_packets;
1878         ppp->stats64.rx_bytes += skb->len - 2;
1879
1880         npi = proto_to_npindex(proto);
1881         if (npi < 0) {
1882                 /* control or unknown frame - pass it to pppd */
1883                 skb_queue_tail(&ppp->file.rq, skb);
1884                 /* limit queue length by dropping old frames */
1885                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1886                        (skb = skb_dequeue(&ppp->file.rq)))
1887                         kfree_skb(skb);
1888                 /* wake up any process polling or blocking on read */
1889                 wake_up_interruptible(&ppp->file.rwait);
1890
1891         } else {
1892                 /* network protocol frame - give it to the kernel */
1893
1894 #ifdef CONFIG_PPP_FILTER
1895                 /* check if the packet passes the pass and active filters */
1896                 /* the filter instructions are constructed assuming
1897                    a four-byte PPP header on each packet */
1898                 if (ppp->pass_filter || ppp->active_filter) {
1899                         if (skb_unclone(skb, GFP_ATOMIC))
1900                                 goto err;
1901
1902                         *skb_push(skb, 2) = 0;
1903                         if (ppp->pass_filter &&
1904                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1905                                 if (ppp->debug & 1)
1906                                         netdev_printk(KERN_DEBUG, ppp->dev,
1907                                                       "PPP: inbound frame "
1908                                                       "not passed\n");
1909                                 kfree_skb(skb);
1910                                 return;
1911                         }
1912                         if (!(ppp->active_filter &&
1913                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1914                                 ppp->last_recv = jiffies;
1915                         __skb_pull(skb, 2);
1916                 } else
1917 #endif /* CONFIG_PPP_FILTER */
1918                         ppp->last_recv = jiffies;
1919
1920                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1921                     ppp->npmode[npi] != NPMODE_PASS) {
1922                         kfree_skb(skb);
1923                 } else {
1924                         /* chop off protocol */
1925                         skb_pull_rcsum(skb, 2);
1926                         skb->dev = ppp->dev;
1927                         skb->protocol = htons(npindex_to_ethertype[npi]);
1928                         skb_reset_mac_header(skb);
1929                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
1930                                                       dev_net(ppp->dev)));
1931                         netif_rx(skb);
1932                 }
1933         }
1934         return;
1935
1936  err:
1937         kfree_skb(skb);
1938         ppp_receive_error(ppp);
1939 }
1940
1941 static struct sk_buff *
1942 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1943 {
1944         int proto = PPP_PROTO(skb);
1945         struct sk_buff *ns;
1946         int len;
1947
1948         /* Until we fix all the decompressor's need to make sure
1949          * data portion is linear.
1950          */
1951         if (!pskb_may_pull(skb, skb->len))
1952                 goto err;
1953
1954         if (proto == PPP_COMP) {
1955                 int obuff_size;
1956
1957                 switch(ppp->rcomp->compress_proto) {
1958                 case CI_MPPE:
1959                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1960                         break;
1961                 default:
1962                         obuff_size = ppp->mru + PPP_HDRLEN;
1963                         break;
1964                 }
1965
1966                 ns = dev_alloc_skb(obuff_size);
1967                 if (!ns) {
1968                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1969                                    "no memory\n");
1970                         goto err;
1971                 }
1972                 /* the decompressor still expects the A/C bytes in the hdr */
1973                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1974                                 skb->len + 2, ns->data, obuff_size);
1975                 if (len < 0) {
1976                         /* Pass the compressed frame to pppd as an
1977                            error indication. */
1978                         if (len == DECOMP_FATALERROR)
1979                                 ppp->rstate |= SC_DC_FERROR;
1980                         kfree_skb(ns);
1981                         goto err;
1982                 }
1983
1984                 consume_skb(skb);
1985                 skb = ns;
1986                 skb_put(skb, len);
1987                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1988
1989         } else {
1990                 /* Uncompressed frame - pass to decompressor so it
1991                    can update its dictionary if necessary. */
1992                 if (ppp->rcomp->incomp)
1993                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1994                                            skb->len + 2);
1995         }
1996
1997         return skb;
1998
1999  err:
2000         ppp->rstate |= SC_DC_ERROR;
2001         ppp_receive_error(ppp);
2002         return skb;
2003 }
2004
2005 #ifdef CONFIG_PPP_MULTILINK
2006 /*
2007  * Receive a multilink frame.
2008  * We put it on the reconstruction queue and then pull off
2009  * as many completed frames as we can.
2010  */
2011 static void
2012 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2013 {
2014         u32 mask, seq;
2015         struct channel *ch;
2016         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2017
2018         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2019                 goto err;               /* no good, throw it away */
2020
2021         /* Decode sequence number and begin/end bits */
2022         if (ppp->flags & SC_MP_SHORTSEQ) {
2023                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2024                 mask = 0xfff;
2025         } else {
2026                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2027                 mask = 0xffffff;
2028         }
2029         PPP_MP_CB(skb)->BEbits = skb->data[2];
2030         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2031
2032         /*
2033          * Do protocol ID decompression on the first fragment of each packet.
2034          */
2035         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2036                 *skb_push(skb, 1) = 0;
2037
2038         /*
2039          * Expand sequence number to 32 bits, making it as close
2040          * as possible to ppp->minseq.
2041          */
2042         seq |= ppp->minseq & ~mask;
2043         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2044                 seq += mask + 1;
2045         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2046                 seq -= mask + 1;        /* should never happen */
2047         PPP_MP_CB(skb)->sequence = seq;
2048         pch->lastseq = seq;
2049
2050         /*
2051          * If this packet comes before the next one we were expecting,
2052          * drop it.
2053          */
2054         if (seq_before(seq, ppp->nextseq)) {
2055                 kfree_skb(skb);
2056                 ++ppp->dev->stats.rx_dropped;
2057                 ppp_receive_error(ppp);
2058                 return;
2059         }
2060
2061         /*
2062          * Reevaluate minseq, the minimum over all channels of the
2063          * last sequence number received on each channel.  Because of
2064          * the increasing sequence number rule, we know that any fragment
2065          * before `minseq' which hasn't arrived is never going to arrive.
2066          * The list of channels can't change because we have the receive
2067          * side of the ppp unit locked.
2068          */
2069         list_for_each_entry(ch, &ppp->channels, clist) {
2070                 if (seq_before(ch->lastseq, seq))
2071                         seq = ch->lastseq;
2072         }
2073         if (seq_before(ppp->minseq, seq))
2074                 ppp->minseq = seq;
2075
2076         /* Put the fragment on the reconstruction queue */
2077         ppp_mp_insert(ppp, skb);
2078
2079         /* If the queue is getting long, don't wait any longer for packets
2080            before the start of the queue. */
2081         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2082                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2083                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2084                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2085         }
2086
2087         /* Pull completed packets off the queue and receive them. */
2088         while ((skb = ppp_mp_reconstruct(ppp))) {
2089                 if (pskb_may_pull(skb, 2))
2090                         ppp_receive_nonmp_frame(ppp, skb);
2091                 else {
2092                         ++ppp->dev->stats.rx_length_errors;
2093                         kfree_skb(skb);
2094                         ppp_receive_error(ppp);
2095                 }
2096         }
2097
2098         return;
2099
2100  err:
2101         kfree_skb(skb);
2102         ppp_receive_error(ppp);
2103 }
2104
2105 /*
2106  * Insert a fragment on the MP reconstruction queue.
2107  * The queue is ordered by increasing sequence number.
2108  */
2109 static void
2110 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2111 {
2112         struct sk_buff *p;
2113         struct sk_buff_head *list = &ppp->mrq;
2114         u32 seq = PPP_MP_CB(skb)->sequence;
2115
2116         /* N.B. we don't need to lock the list lock because we have the
2117            ppp unit receive-side lock. */
2118         skb_queue_walk(list, p) {
2119                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2120                         break;
2121         }
2122         __skb_queue_before(list, p, skb);
2123 }
2124
2125 /*
2126  * Reconstruct a packet from the MP fragment queue.
2127  * We go through increasing sequence numbers until we find a
2128  * complete packet, or we get to the sequence number for a fragment
2129  * which hasn't arrived but might still do so.
2130  */
2131 static struct sk_buff *
2132 ppp_mp_reconstruct(struct ppp *ppp)
2133 {
2134         u32 seq = ppp->nextseq;
2135         u32 minseq = ppp->minseq;
2136         struct sk_buff_head *list = &ppp->mrq;
2137         struct sk_buff *p, *tmp;
2138         struct sk_buff *head, *tail;
2139         struct sk_buff *skb = NULL;
2140         int lost = 0, len = 0;
2141
2142         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2143                 return NULL;
2144         head = list->next;
2145         tail = NULL;
2146         skb_queue_walk_safe(list, p, tmp) {
2147         again:
2148                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2149                         /* this can't happen, anyway ignore the skb */
2150                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2151                                    "seq %u < %u\n",
2152                                    PPP_MP_CB(p)->sequence, seq);
2153                         __skb_unlink(p, list);
2154                         kfree_skb(p);
2155                         continue;
2156                 }
2157                 if (PPP_MP_CB(p)->sequence != seq) {
2158                         u32 oldseq;
2159                         /* Fragment `seq' is missing.  If it is after
2160                            minseq, it might arrive later, so stop here. */
2161                         if (seq_after(seq, minseq))
2162                                 break;
2163                         /* Fragment `seq' is lost, keep going. */
2164                         lost = 1;
2165                         oldseq = seq;
2166                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2167                                 minseq + 1: PPP_MP_CB(p)->sequence;
2168
2169                         if (ppp->debug & 1)
2170                                 netdev_printk(KERN_DEBUG, ppp->dev,
2171                                               "lost frag %u..%u\n",
2172                                               oldseq, seq-1);
2173
2174                         goto again;
2175                 }
2176
2177                 /*
2178                  * At this point we know that all the fragments from
2179                  * ppp->nextseq to seq are either present or lost.
2180                  * Also, there are no complete packets in the queue
2181                  * that have no missing fragments and end before this
2182                  * fragment.
2183                  */
2184
2185                 /* B bit set indicates this fragment starts a packet */
2186                 if (PPP_MP_CB(p)->BEbits & B) {
2187                         head = p;
2188                         lost = 0;
2189                         len = 0;
2190                 }
2191
2192                 len += p->len;
2193
2194                 /* Got a complete packet yet? */
2195                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2196                     (PPP_MP_CB(head)->BEbits & B)) {
2197                         if (len > ppp->mrru + 2) {
2198                                 ++ppp->dev->stats.rx_length_errors;
2199                                 netdev_printk(KERN_DEBUG, ppp->dev,
2200                                               "PPP: reconstructed packet"
2201                                               " is too long (%d)\n", len);
2202                         } else {
2203                                 tail = p;
2204                                 break;
2205                         }
2206                         ppp->nextseq = seq + 1;
2207                 }
2208
2209                 /*
2210                  * If this is the ending fragment of a packet,
2211                  * and we haven't found a complete valid packet yet,
2212                  * we can discard up to and including this fragment.
2213                  */
2214                 if (PPP_MP_CB(p)->BEbits & E) {
2215                         struct sk_buff *tmp2;
2216
2217                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2218                                 if (ppp->debug & 1)
2219                                         netdev_printk(KERN_DEBUG, ppp->dev,
2220                                                       "discarding frag %u\n",
2221                                                       PPP_MP_CB(p)->sequence);
2222                                 __skb_unlink(p, list);
2223                                 kfree_skb(p);
2224                         }
2225                         head = skb_peek(list);
2226                         if (!head)
2227                                 break;
2228                 }
2229                 ++seq;
2230         }
2231
2232         /* If we have a complete packet, copy it all into one skb. */
2233         if (tail != NULL) {
2234                 /* If we have discarded any fragments,
2235                    signal a receive error. */
2236                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2237                         skb_queue_walk_safe(list, p, tmp) {
2238                                 if (p == head)
2239                                         break;
2240                                 if (ppp->debug & 1)
2241                                         netdev_printk(KERN_DEBUG, ppp->dev,
2242                                                       "discarding frag %u\n",
2243                                                       PPP_MP_CB(p)->sequence);
2244                                 __skb_unlink(p, list);
2245                                 kfree_skb(p);
2246                         }
2247
2248                         if (ppp->debug & 1)
2249                                 netdev_printk(KERN_DEBUG, ppp->dev,
2250                                               "  missed pkts %u..%u\n",
2251                                               ppp->nextseq,
2252                                               PPP_MP_CB(head)->sequence-1);
2253                         ++ppp->dev->stats.rx_dropped;
2254                         ppp_receive_error(ppp);
2255                 }
2256
2257                 skb = head;
2258                 if (head != tail) {
2259                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2260                         p = skb_queue_next(list, head);
2261                         __skb_unlink(skb, list);
2262                         skb_queue_walk_from_safe(list, p, tmp) {
2263                                 __skb_unlink(p, list);
2264                                 *fragpp = p;
2265                                 p->next = NULL;
2266                                 fragpp = &p->next;
2267
2268                                 skb->len += p->len;
2269                                 skb->data_len += p->len;
2270                                 skb->truesize += p->truesize;
2271
2272                                 if (p == tail)
2273                                         break;
2274                         }
2275                 } else {
2276                         __skb_unlink(skb, list);
2277                 }
2278
2279                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2280         }
2281
2282         return skb;
2283 }
2284 #endif /* CONFIG_PPP_MULTILINK */
2285
2286 /*
2287  * Channel interface.
2288  */
2289
2290 /* Create a new, unattached ppp channel. */
2291 int ppp_register_channel(struct ppp_channel *chan)
2292 {
2293         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2294 }
2295
2296 /* Create a new, unattached ppp channel for specified net. */
2297 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2298 {
2299         struct channel *pch;
2300         struct ppp_net *pn;
2301
2302         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2303         if (!pch)
2304                 return -ENOMEM;
2305
2306         pn = ppp_pernet(net);
2307
2308         pch->ppp = NULL;
2309         pch->chan = chan;
2310         pch->chan_net = net;
2311         chan->ppp = pch;
2312         init_ppp_file(&pch->file, CHANNEL);
2313         pch->file.hdrlen = chan->hdrlen;
2314 #ifdef CONFIG_PPP_MULTILINK
2315         pch->lastseq = -1;
2316 #endif /* CONFIG_PPP_MULTILINK */
2317         init_rwsem(&pch->chan_sem);
2318         spin_lock_init(&pch->downl);
2319         rwlock_init(&pch->upl);
2320
2321         spin_lock_bh(&pn->all_channels_lock);
2322         pch->file.index = ++pn->last_channel_index;
2323         list_add(&pch->list, &pn->new_channels);
2324         atomic_inc(&channel_count);
2325         spin_unlock_bh(&pn->all_channels_lock);
2326
2327         return 0;
2328 }
2329
2330 /*
2331  * Return the index of a channel.
2332  */
2333 int ppp_channel_index(struct ppp_channel *chan)
2334 {
2335         struct channel *pch = chan->ppp;
2336
2337         if (pch)
2338                 return pch->file.index;
2339         return -1;
2340 }
2341
2342 /*
2343  * Return the PPP unit number to which a channel is connected.
2344  */
2345 int ppp_unit_number(struct ppp_channel *chan)
2346 {
2347         struct channel *pch = chan->ppp;
2348         int unit = -1;
2349
2350         if (pch) {
2351                 read_lock_bh(&pch->upl);
2352                 if (pch->ppp)
2353                         unit = pch->ppp->file.index;
2354                 read_unlock_bh(&pch->upl);
2355         }
2356         return unit;
2357 }
2358
2359 /*
2360  * Return the PPP device interface name of a channel.
2361  */
2362 char *ppp_dev_name(struct ppp_channel *chan)
2363 {
2364         struct channel *pch = chan->ppp;
2365         char *name = NULL;
2366
2367         if (pch) {
2368                 read_lock_bh(&pch->upl);
2369                 if (pch->ppp && pch->ppp->dev)
2370                         name = pch->ppp->dev->name;
2371                 read_unlock_bh(&pch->upl);
2372         }
2373         return name;
2374 }
2375
2376
2377 /*
2378  * Disconnect a channel from the generic layer.
2379  * This must be called in process context.
2380  */
2381 void
2382 ppp_unregister_channel(struct ppp_channel *chan)
2383 {
2384         struct channel *pch = chan->ppp;
2385         struct ppp_net *pn;
2386
2387         if (!pch)
2388                 return;         /* should never happen */
2389
2390         chan->ppp = NULL;
2391
2392         /*
2393          * This ensures that we have returned from any calls into the
2394          * the channel's start_xmit or ioctl routine before we proceed.
2395          */
2396         down_write(&pch->chan_sem);
2397         spin_lock_bh(&pch->downl);
2398         pch->chan = NULL;
2399         spin_unlock_bh(&pch->downl);
2400         up_write(&pch->chan_sem);
2401         ppp_disconnect_channel(pch);
2402
2403         pn = ppp_pernet(pch->chan_net);
2404         spin_lock_bh(&pn->all_channels_lock);
2405         list_del(&pch->list);
2406         spin_unlock_bh(&pn->all_channels_lock);
2407
2408         pch->file.dead = 1;
2409         wake_up_interruptible(&pch->file.rwait);
2410         if (atomic_dec_and_test(&pch->file.refcnt))
2411                 ppp_destroy_channel(pch);
2412 }
2413
2414 /*
2415  * Callback from a channel when it can accept more to transmit.
2416  * This should be called at BH/softirq level, not interrupt level.
2417  */
2418 void
2419 ppp_output_wakeup(struct ppp_channel *chan)
2420 {
2421         struct channel *pch = chan->ppp;
2422
2423         if (!pch)
2424                 return;
2425         ppp_channel_push(pch);
2426 }
2427
2428 /*
2429  * Compression control.
2430  */
2431
2432 /* Process the PPPIOCSCOMPRESS ioctl. */
2433 static int
2434 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2435 {
2436         int err;
2437         struct compressor *cp, *ocomp;
2438         struct ppp_option_data data;
2439         void *state, *ostate;
2440         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2441
2442         err = -EFAULT;
2443         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2444                 goto out;
2445         if (data.length > CCP_MAX_OPTION_LENGTH)
2446                 goto out;
2447         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2448                 goto out;
2449
2450         err = -EINVAL;
2451         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2452                 goto out;
2453
2454         cp = try_then_request_module(
2455                 find_compressor(ccp_option[0]),
2456                 "ppp-compress-%d", ccp_option[0]);
2457         if (!cp)
2458                 goto out;
2459
2460         err = -ENOBUFS;
2461         if (data.transmit) {
2462                 state = cp->comp_alloc(ccp_option, data.length);
2463                 if (state) {
2464                         ppp_xmit_lock(ppp);
2465                         ppp->xstate &= ~SC_COMP_RUN;
2466                         ocomp = ppp->xcomp;
2467                         ostate = ppp->xc_state;
2468                         ppp->xcomp = cp;
2469                         ppp->xc_state = state;
2470                         ppp_xmit_unlock(ppp);
2471                         if (ostate) {
2472                                 ocomp->comp_free(ostate);
2473                                 module_put(ocomp->owner);
2474                         }
2475                         err = 0;
2476                 } else
2477                         module_put(cp->owner);
2478
2479         } else {
2480                 state = cp->decomp_alloc(ccp_option, data.length);
2481                 if (state) {
2482                         ppp_recv_lock(ppp);
2483                         ppp->rstate &= ~SC_DECOMP_RUN;
2484                         ocomp = ppp->rcomp;
2485                         ostate = ppp->rc_state;
2486                         ppp->rcomp = cp;
2487                         ppp->rc_state = state;
2488                         ppp_recv_unlock(ppp);
2489                         if (ostate) {
2490                                 ocomp->decomp_free(ostate);
2491                                 module_put(ocomp->owner);
2492                         }
2493                         err = 0;
2494                 } else
2495                         module_put(cp->owner);
2496         }
2497
2498  out:
2499         return err;
2500 }
2501
2502 /*
2503  * Look at a CCP packet and update our state accordingly.
2504  * We assume the caller has the xmit or recv path locked.
2505  */
2506 static void
2507 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2508 {
2509         unsigned char *dp;
2510         int len;
2511
2512         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2513                 return; /* no header */
2514         dp = skb->data + 2;
2515
2516         switch (CCP_CODE(dp)) {
2517         case CCP_CONFREQ:
2518
2519                 /* A ConfReq starts negotiation of compression
2520                  * in one direction of transmission,
2521                  * and hence brings it down...but which way?
2522                  *
2523                  * Remember:
2524                  * A ConfReq indicates what the sender would like to receive
2525                  */
2526                 if(inbound)
2527                         /* He is proposing what I should send */
2528                         ppp->xstate &= ~SC_COMP_RUN;
2529                 else
2530                         /* I am proposing to what he should send */
2531                         ppp->rstate &= ~SC_DECOMP_RUN;
2532
2533                 break;
2534
2535         case CCP_TERMREQ:
2536         case CCP_TERMACK:
2537                 /*
2538                  * CCP is going down, both directions of transmission
2539                  */
2540                 ppp->rstate &= ~SC_DECOMP_RUN;
2541                 ppp->xstate &= ~SC_COMP_RUN;
2542                 break;
2543
2544         case CCP_CONFACK:
2545                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2546                         break;
2547                 len = CCP_LENGTH(dp);
2548                 if (!pskb_may_pull(skb, len + 2))
2549                         return;         /* too short */
2550                 dp += CCP_HDRLEN;
2551                 len -= CCP_HDRLEN;
2552                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2553                         break;
2554                 if (inbound) {
2555                         /* we will start receiving compressed packets */
2556                         if (!ppp->rc_state)
2557                                 break;
2558                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2559                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2560                                 ppp->rstate |= SC_DECOMP_RUN;
2561                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2562                         }
2563                 } else {
2564                         /* we will soon start sending compressed packets */
2565                         if (!ppp->xc_state)
2566                                 break;
2567                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2568                                         ppp->file.index, 0, ppp->debug))
2569                                 ppp->xstate |= SC_COMP_RUN;
2570                 }
2571                 break;
2572
2573         case CCP_RESETACK:
2574                 /* reset the [de]compressor */
2575                 if ((ppp->flags & SC_CCP_UP) == 0)
2576                         break;
2577                 if (inbound) {
2578                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2579                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2580                                 ppp->rstate &= ~SC_DC_ERROR;
2581                         }
2582                 } else {
2583                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2584                                 ppp->xcomp->comp_reset(ppp->xc_state);
2585                 }
2586                 break;
2587         }
2588 }
2589
2590 /* Free up compression resources. */
2591 static void
2592 ppp_ccp_closed(struct ppp *ppp)
2593 {
2594         void *xstate, *rstate;
2595         struct compressor *xcomp, *rcomp;
2596
2597         ppp_lock(ppp);
2598         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2599         ppp->xstate = 0;
2600         xcomp = ppp->xcomp;
2601         xstate = ppp->xc_state;
2602         ppp->xc_state = NULL;
2603         ppp->rstate = 0;
2604         rcomp = ppp->rcomp;
2605         rstate = ppp->rc_state;
2606         ppp->rc_state = NULL;
2607         ppp_unlock(ppp);
2608
2609         if (xstate) {
2610                 xcomp->comp_free(xstate);
2611                 module_put(xcomp->owner);
2612         }
2613         if (rstate) {
2614                 rcomp->decomp_free(rstate);
2615                 module_put(rcomp->owner);
2616         }
2617 }
2618
2619 /* List of compressors. */
2620 static LIST_HEAD(compressor_list);
2621 static DEFINE_SPINLOCK(compressor_list_lock);
2622
2623 struct compressor_entry {
2624         struct list_head list;
2625         struct compressor *comp;
2626 };
2627
2628 static struct compressor_entry *
2629 find_comp_entry(int proto)
2630 {
2631         struct compressor_entry *ce;
2632
2633         list_for_each_entry(ce, &compressor_list, list) {
2634                 if (ce->comp->compress_proto == proto)
2635                         return ce;
2636         }
2637         return NULL;
2638 }
2639
2640 /* Register a compressor */
2641 int
2642 ppp_register_compressor(struct compressor *cp)
2643 {
2644         struct compressor_entry *ce;
2645         int ret;
2646         spin_lock(&compressor_list_lock);
2647         ret = -EEXIST;
2648         if (find_comp_entry(cp->compress_proto))
2649                 goto out;
2650         ret = -ENOMEM;
2651         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2652         if (!ce)
2653                 goto out;
2654         ret = 0;
2655         ce->comp = cp;
2656         list_add(&ce->list, &compressor_list);
2657  out:
2658         spin_unlock(&compressor_list_lock);
2659         return ret;
2660 }
2661
2662 /* Unregister a compressor */
2663 void
2664 ppp_unregister_compressor(struct compressor *cp)
2665 {
2666         struct compressor_entry *ce;
2667
2668         spin_lock(&compressor_list_lock);
2669         ce = find_comp_entry(cp->compress_proto);
2670         if (ce && ce->comp == cp) {
2671                 list_del(&ce->list);
2672                 kfree(ce);
2673         }
2674         spin_unlock(&compressor_list_lock);
2675 }
2676
2677 /* Find a compressor. */
2678 static struct compressor *
2679 find_compressor(int type)
2680 {
2681         struct compressor_entry *ce;
2682         struct compressor *cp = NULL;
2683
2684         spin_lock(&compressor_list_lock);
2685         ce = find_comp_entry(type);
2686         if (ce) {
2687                 cp = ce->comp;
2688                 if (!try_module_get(cp->owner))
2689                         cp = NULL;
2690         }
2691         spin_unlock(&compressor_list_lock);
2692         return cp;
2693 }
2694
2695 /*
2696  * Miscelleneous stuff.
2697  */
2698
2699 static void
2700 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2701 {
2702         struct slcompress *vj = ppp->vj;
2703
2704         memset(st, 0, sizeof(*st));
2705         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2706         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2707         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2708         st->p.ppp_opackets = ppp->stats64.tx_packets;
2709         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2710         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2711         if (!vj)
2712                 return;
2713         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2714         st->vj.vjs_compressed = vj->sls_o_compressed;
2715         st->vj.vjs_searches = vj->sls_o_searches;
2716         st->vj.vjs_misses = vj->sls_o_misses;
2717         st->vj.vjs_errorin = vj->sls_i_error;
2718         st->vj.vjs_tossed = vj->sls_i_tossed;
2719         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2720         st->vj.vjs_compressedin = vj->sls_i_compressed;
2721 }
2722
2723 /*
2724  * Stuff for handling the lists of ppp units and channels
2725  * and for initialization.
2726  */
2727
2728 /*
2729  * Create a new ppp interface unit.  Fails if it can't allocate memory
2730  * or if there is already a unit with the requested number.
2731  * unit == -1 means allocate a new number.
2732  */
2733 static struct ppp *ppp_create_interface(struct net *net, int unit,
2734                                         struct file *file, int *retp)
2735 {
2736         struct ppp *ppp;
2737         struct ppp_net *pn;
2738         struct net_device *dev = NULL;
2739         int ret = -ENOMEM;
2740         int i;
2741
2742         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
2743         if (!dev)
2744                 goto out1;
2745
2746         pn = ppp_pernet(net);
2747
2748         ppp = netdev_priv(dev);
2749         ppp->dev = dev;
2750         ppp->mru = PPP_MRU;
2751         init_ppp_file(&ppp->file, INTERFACE);
2752         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2753         ppp->owner = file;
2754         for (i = 0; i < NUM_NP; ++i)
2755                 ppp->npmode[i] = NPMODE_PASS;
2756         INIT_LIST_HEAD(&ppp->channels);
2757         spin_lock_init(&ppp->rlock);
2758         spin_lock_init(&ppp->wlock);
2759 #ifdef CONFIG_PPP_MULTILINK
2760         ppp->minseq = -1;
2761         skb_queue_head_init(&ppp->mrq);
2762 #endif /* CONFIG_PPP_MULTILINK */
2763 #ifdef CONFIG_PPP_FILTER
2764         ppp->pass_filter = NULL;
2765         ppp->active_filter = NULL;
2766 #endif /* CONFIG_PPP_FILTER */
2767
2768         /*
2769          * drum roll: don't forget to set
2770          * the net device is belong to
2771          */
2772         dev_net_set(dev, net);
2773
2774         rtnl_lock();
2775         mutex_lock(&pn->all_ppp_mutex);
2776
2777         if (unit < 0) {
2778                 unit = unit_get(&pn->units_idr, ppp);
2779                 if (unit < 0) {
2780                         ret = unit;
2781                         goto out2;
2782                 }
2783         } else {
2784                 ret = -EEXIST;
2785                 if (unit_find(&pn->units_idr, unit))
2786                         goto out2; /* unit already exists */
2787                 /*
2788                  * if caller need a specified unit number
2789                  * lets try to satisfy him, otherwise --
2790                  * he should better ask us for new unit number
2791                  *
2792                  * NOTE: yes I know that returning EEXIST it's not
2793                  * fair but at least pppd will ask us to allocate
2794                  * new unit in this case so user is happy :)
2795                  */
2796                 unit = unit_set(&pn->units_idr, ppp, unit);
2797                 if (unit < 0)
2798                         goto out2;
2799         }
2800
2801         /* Initialize the new ppp unit */
2802         ppp->file.index = unit;
2803         sprintf(dev->name, "ppp%d", unit);
2804
2805         ret = register_netdevice(dev);
2806         if (ret != 0) {
2807                 unit_put(&pn->units_idr, unit);
2808                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2809                            dev->name, ret);
2810                 goto out2;
2811         }
2812
2813         ppp->ppp_net = net;
2814
2815         atomic_inc(&ppp_unit_count);
2816         mutex_unlock(&pn->all_ppp_mutex);
2817         rtnl_unlock();
2818
2819         *retp = 0;
2820         return ppp;
2821
2822 out2:
2823         mutex_unlock(&pn->all_ppp_mutex);
2824         rtnl_unlock();
2825         free_netdev(dev);
2826 out1:
2827         *retp = ret;
2828         return NULL;
2829 }
2830
2831 /*
2832  * Initialize a ppp_file structure.
2833  */
2834 static void
2835 init_ppp_file(struct ppp_file *pf, int kind)
2836 {
2837         pf->kind = kind;
2838         skb_queue_head_init(&pf->xq);
2839         skb_queue_head_init(&pf->rq);
2840         atomic_set(&pf->refcnt, 1);
2841         init_waitqueue_head(&pf->rwait);
2842 }
2843
2844 /*
2845  * Free the memory used by a ppp unit.  This is only called once
2846  * there are no channels connected to the unit and no file structs
2847  * that reference the unit.
2848  */
2849 static void ppp_destroy_interface(struct ppp *ppp)
2850 {
2851         atomic_dec(&ppp_unit_count);
2852
2853         if (!ppp->file.dead || ppp->n_channels) {
2854                 /* "can't happen" */
2855                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2856                            "but dead=%d n_channels=%d !\n",
2857                            ppp, ppp->file.dead, ppp->n_channels);
2858                 return;
2859         }
2860
2861         ppp_ccp_closed(ppp);
2862         if (ppp->vj) {
2863                 slhc_free(ppp->vj);
2864                 ppp->vj = NULL;
2865         }
2866         skb_queue_purge(&ppp->file.xq);
2867         skb_queue_purge(&ppp->file.rq);
2868 #ifdef CONFIG_PPP_MULTILINK
2869         skb_queue_purge(&ppp->mrq);
2870 #endif /* CONFIG_PPP_MULTILINK */
2871 #ifdef CONFIG_PPP_FILTER
2872         if (ppp->pass_filter) {
2873                 bpf_prog_destroy(ppp->pass_filter);
2874                 ppp->pass_filter = NULL;
2875         }
2876
2877         if (ppp->active_filter) {
2878                 bpf_prog_destroy(ppp->active_filter);
2879                 ppp->active_filter = NULL;
2880         }
2881 #endif /* CONFIG_PPP_FILTER */
2882
2883         kfree_skb(ppp->xmit_pending);
2884
2885         free_netdev(ppp->dev);
2886 }
2887
2888 /*
2889  * Locate an existing ppp unit.
2890  * The caller should have locked the all_ppp_mutex.
2891  */
2892 static struct ppp *
2893 ppp_find_unit(struct ppp_net *pn, int unit)
2894 {
2895         return unit_find(&pn->units_idr, unit);
2896 }
2897
2898 /*
2899  * Locate an existing ppp channel.
2900  * The caller should have locked the all_channels_lock.
2901  * First we look in the new_channels list, then in the
2902  * all_channels list.  If found in the new_channels list,
2903  * we move it to the all_channels list.  This is for speed
2904  * when we have a lot of channels in use.
2905  */
2906 static struct channel *
2907 ppp_find_channel(struct ppp_net *pn, int unit)
2908 {
2909         struct channel *pch;
2910
2911         list_for_each_entry(pch, &pn->new_channels, list) {
2912                 if (pch->file.index == unit) {
2913                         list_move(&pch->list, &pn->all_channels);
2914                         return pch;
2915                 }
2916         }
2917
2918         list_for_each_entry(pch, &pn->all_channels, list) {
2919                 if (pch->file.index == unit)
2920                         return pch;
2921         }
2922
2923         return NULL;
2924 }
2925
2926 /*
2927  * Connect a PPP channel to a PPP interface unit.
2928  */
2929 static int
2930 ppp_connect_channel(struct channel *pch, int unit)
2931 {
2932         struct ppp *ppp;
2933         struct ppp_net *pn;
2934         int ret = -ENXIO;
2935         int hdrlen;
2936
2937         pn = ppp_pernet(pch->chan_net);
2938
2939         mutex_lock(&pn->all_ppp_mutex);
2940         ppp = ppp_find_unit(pn, unit);
2941         if (!ppp)
2942                 goto out;
2943         write_lock_bh(&pch->upl);
2944         ret = -EINVAL;
2945         if (pch->ppp)
2946                 goto outl;
2947
2948         ppp_lock(ppp);
2949         if (pch->file.hdrlen > ppp->file.hdrlen)
2950                 ppp->file.hdrlen = pch->file.hdrlen;
2951         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2952         if (hdrlen > ppp->dev->hard_header_len)
2953                 ppp->dev->hard_header_len = hdrlen;
2954         list_add_tail(&pch->clist, &ppp->channels);
2955         ++ppp->n_channels;
2956         pch->ppp = ppp;
2957         atomic_inc(&ppp->file.refcnt);
2958         ppp_unlock(ppp);
2959         ret = 0;
2960
2961  outl:
2962         write_unlock_bh(&pch->upl);
2963  out:
2964         mutex_unlock(&pn->all_ppp_mutex);
2965         return ret;
2966 }
2967
2968 /*
2969  * Disconnect a channel from its ppp unit.
2970  */
2971 static int
2972 ppp_disconnect_channel(struct channel *pch)
2973 {
2974         struct ppp *ppp;
2975         int err = -EINVAL;
2976
2977         write_lock_bh(&pch->upl);
2978         ppp = pch->ppp;
2979         pch->ppp = NULL;
2980         write_unlock_bh(&pch->upl);
2981         if (ppp) {
2982                 /* remove it from the ppp unit's list */
2983                 ppp_lock(ppp);
2984                 list_del(&pch->clist);
2985                 if (--ppp->n_channels == 0)
2986                         wake_up_interruptible(&ppp->file.rwait);
2987                 ppp_unlock(ppp);
2988                 if (atomic_dec_and_test(&ppp->file.refcnt))
2989                         ppp_destroy_interface(ppp);
2990                 err = 0;
2991         }
2992         return err;
2993 }
2994
2995 /*
2996  * Free up the resources used by a ppp channel.
2997  */
2998 static void ppp_destroy_channel(struct channel *pch)
2999 {
3000         atomic_dec(&channel_count);
3001
3002         if (!pch->file.dead) {
3003                 /* "can't happen" */
3004                 pr_err("ppp: destroying undead channel %p !\n", pch);
3005                 return;
3006         }
3007         skb_queue_purge(&pch->file.xq);
3008         skb_queue_purge(&pch->file.rq);
3009         kfree(pch);
3010 }
3011
3012 static void __exit ppp_cleanup(void)
3013 {
3014         /* should never happen */
3015         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3016                 pr_err("PPP: removing module but units remain!\n");
3017         unregister_chrdev(PPP_MAJOR, "ppp");
3018         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3019         class_destroy(ppp_class);
3020         unregister_pernet_device(&ppp_net_ops);
3021 }
3022
3023 /*
3024  * Units handling. Caller must protect concurrent access
3025  * by holding all_ppp_mutex
3026  */
3027
3028 /* associate pointer with specified number */
3029 static int unit_set(struct idr *p, void *ptr, int n)
3030 {
3031         int unit;
3032
3033         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3034         if (unit == -ENOSPC)
3035                 unit = -EINVAL;
3036         return unit;
3037 }
3038
3039 /* get new free unit number and associate pointer with it */
3040 static int unit_get(struct idr *p, void *ptr)
3041 {
3042         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3043 }
3044
3045 /* put unit number back to a pool */
3046 static void unit_put(struct idr *p, int n)
3047 {
3048         idr_remove(p, n);
3049 }
3050
3051 /* get pointer associated with the number */
3052 static void *unit_find(struct idr *p, int n)
3053 {
3054         return idr_find(p, n);
3055 }
3056
3057 /* Module/initialization stuff */
3058
3059 module_init(ppp_init);
3060 module_exit(ppp_cleanup);
3061
3062 EXPORT_SYMBOL(ppp_register_net_channel);
3063 EXPORT_SYMBOL(ppp_register_channel);
3064 EXPORT_SYMBOL(ppp_unregister_channel);
3065 EXPORT_SYMBOL(ppp_channel_index);
3066 EXPORT_SYMBOL(ppp_unit_number);
3067 EXPORT_SYMBOL(ppp_dev_name);
3068 EXPORT_SYMBOL(ppp_input);
3069 EXPORT_SYMBOL(ppp_input_error);
3070 EXPORT_SYMBOL(ppp_output_wakeup);
3071 EXPORT_SYMBOL(ppp_register_compressor);
3072 EXPORT_SYMBOL(ppp_unregister_compressor);
3073 MODULE_LICENSE("GPL");
3074 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3075 MODULE_ALIAS("devname:ppp");