drivers/net/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 20020217==
  23  */
  24
  25 #include <linux/config.h>
  26 #include <linux/module.h>
  27 #include <linux/kernel.h>
  28 #include <linux/kmod.h>
  29 #include <linux/init.h>
  30 #include <linux/list.h>
  31 #include <linux/devfs_fs_kernel.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/poll.h>
  34 #include <linux/ppp_defs.h>
  35 #include <linux/filter.h>
  36 #include <linux/if_ppp.h>
  37 #include <linux/ppp_channel.h>
  38 #include <linux/ppp-comp.h>
  39 #include <linux/skbuff.h>
  40 #include <linux/rtnetlink.h>
  41 #include <linux/if_arp.h>
  42 #include <linux/ip.h>
  43 #include <linux/tcp.h>
  44 #include <linux/spinlock.h>
  45 #include <linux/smp_lock.h>
  46 #include <linux/rwsem.h>
  47 #include <linux/stddef.h>
  48 #include <linux/device.h>
  49 #include <net/slhc_vj.h>
  50 #include <asm/atomic.h>
  51
  52 #define PPP_VERSION     "2.4.2"
  53
  54 /*
  55  * Network protocols we support.
  56  */
  57 #define NP_IP   0               /* Internet Protocol V4 */
  58 #define NP_IPV6 1               /* Internet Protocol V6 */
  59 #define NP_IPX  2               /* IPX protocol */
  60 #define NP_AT   3               /* Appletalk protocol */
  61 #define NP_MPLS_UC 4            /* MPLS unicast */
  62 #define NP_MPLS_MC 5            /* MPLS multicast */
  63 #define NUM_NP  6               /* Number of NPs. */
  64
  65 #define MPHDRLEN        6       /* multilink protocol header length */
  66 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  67 #define MIN_FRAG_SIZE   64
  68
  69 /*
  70  * An instance of /dev/ppp can be associated with either a ppp
  71  * interface unit or a ppp channel.  In both cases, file->private_data
  72  * points to one of these.
  73  */
  74 struct ppp_file {
  75         enum {
  76                 INTERFACE=1, CHANNEL
  77         }               kind;
  78         struct sk_buff_head xq;         /* pppd transmit queue */
  79         struct sk_buff_head rq;         /* receive queue for pppd */
  80         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  81         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  82         int             hdrlen;         /* space to leave for headers */
  83         int             index;          /* interface unit / channel number */
  84         int             dead;           /* unit/channel has been shut down */
  85 };
  86
  87 #define PF_TO_X(pf, X)          ((X *)((char *)(pf) - offsetof(X, file)))
  88
  89 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  90 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  91
  92 #define ROUNDUP(n, x)           (((n) + (x) - 1) / (x))
  93
  94 /*
  95  * Data structure describing one ppp unit.
  96  * A ppp unit corresponds to a ppp network interface device
  97  * and represents a multilink bundle.
  98  * It can have 0 or more ppp channels connected to it.
  99  */
 100 struct ppp {
 101         struct ppp_file file;           /* stuff for read/write/poll 0 */
 102         struct file     *owner;         /* file that owns this unit 48 */
 103         struct list_head channels;      /* list of attached channels 4c */
 104         int             n_channels;     /* how many channels are attached 54 */
 105         spinlock_t      rlock;          /* lock for receive side 58 */
 106         spinlock_t      wlock;          /* lock for transmit side 5c */
 107         int             mru;            /* max receive unit 60 */
 108         unsigned int    flags;          /* control bits 64 */
 109         unsigned int    xstate;         /* transmit state bits 68 */
 110         unsigned int    rstate;         /* receive state bits 6c */
 111         int             debug;          /* debug flags 70 */
 112         struct slcompress *vj;          /* state for VJ header compression */
 113         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 114         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 115         struct compressor *xcomp;       /* transmit packet compressor 8c */
 116         void            *xc_state;      /* its internal state 90 */
 117         struct compressor *rcomp;       /* receive decompressor 94 */
 118         void            *rc_state;      /* its internal state 98 */
 119         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 120         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 121         struct net_device *dev;         /* network interface device a4 */
 122 #ifdef CONFIG_PPP_MULTILINK
 123         int             nxchan;         /* next channel to send something on */
 124         u32             nxseq;          /* next sequence number to send */
 125         int             mrru;           /* MP: max reconst. receive unit */
 126         u32             nextseq;        /* MP: seq no of next packet */
 127         u32             minseq;         /* MP: min of most recent seqnos */
 128         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 129 #endif /* CONFIG_PPP_MULTILINK */
 130         struct net_device_stats stats;  /* statistics */
 131 #ifdef CONFIG_PPP_FILTER
 132         struct sock_filter *pass_filter;        /* filter for packets to pass */
 133         struct sock_filter *active_filter;/* filter for pkts to reset idle */
 134         unsigned pass_len, active_len;
 135 #endif /* CONFIG_PPP_FILTER */
 136 };
 137
 138 /*
 139  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 140  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP.
 141  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 142  * Bits in xstate: SC_COMP_RUN
 143  */
 144 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 145                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 146                          |SC_COMP_TCP|SC_REJ_COMP_TCP)
 147
 148 /*
 149  * Private data structure for each channel.
 150  * This includes the data structure used for multilink.
 151  */
 152 struct channel {
 153         struct ppp_file file;           /* stuff for read/write/poll */
 154         struct list_head list;          /* link in all/new_channels list */
 155         struct ppp_channel *chan;       /* public channel data structure */
 156         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 157         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 158         struct ppp      *ppp;           /* ppp unit we're connected to */
 159         struct list_head clist;         /* link in list of channels per unit */
 160         rwlock_t        upl;            /* protects `ppp' */
 161 #ifdef CONFIG_PPP_MULTILINK
 162         u8              avail;          /* flag used in multilink stuff */
 163         u8              had_frag;       /* >= 1 fragments have been sent */
 164         u32             lastseq;        /* MP: last sequence # received */
 165 #endif /* CONFIG_PPP_MULTILINK */
 166 };
 167
 168 /*
 169  * SMP locking issues:
 170  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 171  * list and the ppp.n_channels field, you need to take both locks
 172  * before you modify them.
 173  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 174  * channel.downl.
 175  */
 176
 177 /*
 178  * A cardmap represents a mapping from unsigned integers to pointers,
 179  * and provides a fast "find lowest unused number" operation.
 180  * It uses a broad (32-way) tree with a bitmap at each level.
 181  * It is designed to be space-efficient for small numbers of entries
 182  * and time-efficient for large numbers of entries.
 183  */
 184 #define CARDMAP_ORDER   5
 185 #define CARDMAP_WIDTH   (1U << CARDMAP_ORDER)
 186 #define CARDMAP_MASK    (CARDMAP_WIDTH - 1)
 187
 188 struct cardmap {
 189         int shift;
 190         unsigned long inuse;
 191         struct cardmap *parent;
 192         void *ptr[CARDMAP_WIDTH];
 193 };
 194 static void *cardmap_get(struct cardmap *map, unsigned int nr);
 195 static void cardmap_set(struct cardmap **map, unsigned int nr, void *ptr);
 196 static unsigned int cardmap_find_first_free(struct cardmap *map);
 197 static void cardmap_destroy(struct cardmap **map);
 198
 199 /*
 200  * all_ppp_sem protects the all_ppp_units mapping.
 201  * It also ensures that finding a ppp unit in the all_ppp_units map
 202  * and updating its file.refcnt field is atomic.
 203  */
 204 static DECLARE_MUTEX(all_ppp_sem);
 205 static struct cardmap *all_ppp_units;
 206 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 207
 208 /*
 209  * all_channels_lock protects all_channels and last_channel_index,
 210  * and the atomicity of find a channel and updating its file.refcnt
 211  * field.
 212  */
 213 static spinlock_t all_channels_lock = SPIN_LOCK_UNLOCKED;
 214 static LIST_HEAD(all_channels);
 215 static LIST_HEAD(new_channels);
 216 static int last_channel_index;
 217 static atomic_t channel_count = ATOMIC_INIT(0);
 218
 219 /* Get the PPP protocol number from a skb */
 220 #define PPP_PROTO(skb)  (((skb)->data[0] << 8) + (skb)->data[1])
 221
 222 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 223 #define PPP_MAX_RQLEN   32
 224
 225 /*
 226  * Maximum number of multilink fragments queued up.
 227  * This has to be large enough to cope with the maximum latency of
 228  * the slowest channel relative to the others.  Strictly it should
 229  * depend on the number of channels and their characteristics.
 230  */
 231 #define PPP_MP_MAX_QLEN 128
 232
 233 /* Multilink header bits. */
 234 #define B       0x80            /* this fragment begins a packet */
 235 #define E       0x40            /* this fragment ends a packet */
 236
 237 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 238 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 239 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 240
 241 /* Prototypes. */
 242 static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
 243                                 unsigned int cmd, unsigned long arg);
 244 static void ppp_xmit_process(struct ppp *ppp);
 245 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 246 static void ppp_push(struct ppp *ppp);
 247 static void ppp_channel_push(struct channel *pch);
 248 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 249                               struct channel *pch);
 250 static void ppp_receive_error(struct ppp *ppp);
 251 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 252 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 253                                             struct sk_buff *skb);
 254 #ifdef CONFIG_PPP_MULTILINK
 255 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 256                                 struct channel *pch);
 257 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 258 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 259 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 260 #endif /* CONFIG_PPP_MULTILINK */
 261 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 262 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 263 static void ppp_ccp_closed(struct ppp *ppp);
 264 static struct compressor *find_compressor(int type);
 265 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 266 static struct ppp *ppp_create_interface(int unit, int *retp);
 267 static void init_ppp_file(struct ppp_file *pf, int kind);
 268 static void ppp_shutdown_interface(struct ppp *ppp);
 269 static void ppp_destroy_interface(struct ppp *ppp);
 270 static struct ppp *ppp_find_unit(int unit);
 271 static struct channel *ppp_find_channel(int unit);
 272 static int ppp_connect_channel(struct channel *pch, int unit);
 273 static int ppp_disconnect_channel(struct channel *pch);
 274 static void ppp_destroy_channel(struct channel *pch);
 275
 276 static struct class_simple *ppp_class;
 277
 278 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 279 static inline int proto_to_npindex(int proto)
 280 {
 281         switch (proto) {
 282         case PPP_IP:
 283                 return NP_IP;
 284         case PPP_IPV6:
 285                 return NP_IPV6;
 286         case PPP_IPX:
 287                 return NP_IPX;
 288         case PPP_AT:
 289                 return NP_AT;
 290         case PPP_MPLS_UC:
 291                 return NP_MPLS_UC;
 292         case PPP_MPLS_MC:
 293                 return NP_MPLS_MC;
 294         }
 295         return -EINVAL;
 296 }
 297
 298 /* Translates an NP index into a PPP protocol number */
 299 static const int npindex_to_proto[NUM_NP] = {
 300         PPP_IP,
 301         PPP_IPV6,
 302         PPP_IPX,
 303         PPP_AT,
 304         PPP_MPLS_UC,
 305         PPP_MPLS_MC,
 306 };
 307
 308 /* Translates an ethertype into an NP index */
 309 static inline int ethertype_to_npindex(int ethertype)
 310 {
 311         switch (ethertype) {
 312         case ETH_P_IP:
 313                 return NP_IP;
 314         case ETH_P_IPV6:
 315                 return NP_IPV6;
 316         case ETH_P_IPX:
 317                 return NP_IPX;
 318         case ETH_P_PPPTALK:
 319         case ETH_P_ATALK:
 320                 return NP_AT;
 321         case ETH_P_MPLS_UC:
 322                 return NP_MPLS_UC;
 323         case ETH_P_MPLS_MC:
 324                 return NP_MPLS_MC;
 325         }
 326         return -1;
 327 }
 328
 329 /* Translates an NP index into an ethertype */
 330 static const int npindex_to_ethertype[NUM_NP] = {
 331         ETH_P_IP,
 332         ETH_P_IPV6,
 333         ETH_P_IPX,
 334         ETH_P_PPPTALK,
 335         ETH_P_MPLS_UC,
 336         ETH_P_MPLS_MC,
 337 };
 338
 339 /*
 340  * Locking shorthand.
 341  */
 342 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 343 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 344 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 345 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 346 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 347                                      ppp_recv_lock(ppp); } while (0)
 348 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 349                                      ppp_xmit_unlock(ppp); } while (0)
 350
 351 /*
 352  * /dev/ppp device routines.
 353  * The /dev/ppp device is used by pppd to control the ppp unit.
 354  * It supports the read, write, ioctl and poll functions.
 355  * Open instances of /dev/ppp can be in one of three states:
 356  * unattached, attached to a ppp unit, or attached to a ppp channel.
 357  */
 358 static int ppp_open(struct inode *inode, struct file *file)
 359 {
 360         /*
 361          * This could (should?) be enforced by the permissions on /dev/ppp.
 362          */
 363         if (!capable(CAP_NET_ADMIN))
 364                 return -EPERM;
 365         return 0;
 366 }
 367
 368 static int ppp_release(struct inode *inode, struct file *file)
 369 {
 370         struct ppp_file *pf = file->private_data;
 371         struct ppp *ppp;
 372
 373         if (pf != 0) {
 374                 file->private_data = NULL;
 375                 if (pf->kind == INTERFACE) {
 376                         ppp = PF_TO_PPP(pf);
 377                         if (file == ppp->owner)
 378                                 ppp_shutdown_interface(ppp);
 379                 }
 380                 if (atomic_dec_and_test(&pf->refcnt)) {
 381                         switch (pf->kind) {
 382                         case INTERFACE:
 383                                 ppp_destroy_interface(PF_TO_PPP(pf));
 384                                 break;
 385                         case CHANNEL:
 386                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 387                                 break;
 388                         }
 389                 }
 390         }
 391         return 0;
 392 }
 393
 394 static ssize_t ppp_read(struct file *file, char __user *buf,
 395                         size_t count, loff_t *ppos)
 396 {
 397         struct ppp_file *pf = file->private_data;
 398         DECLARE_WAITQUEUE(wait, current);
 399         ssize_t ret;
 400         struct sk_buff *skb = NULL;
 401
 402         ret = count;
 403
 404         if (pf == 0)
 405                 return -ENXIO;
 406         add_wait_queue(&pf->rwait, &wait);
 407         for (;;) {
 408                 set_current_state(TASK_INTERRUPTIBLE);
 409                 skb = skb_dequeue(&pf->rq);
 410                 if (skb)
 411                         break;
 412                 ret = 0;
 413                 if (pf->dead)
 414                         break;
 415                 ret = -EAGAIN;
 416                 if (file->f_flags & O_NONBLOCK)
 417                         break;
 418                 ret = -ERESTARTSYS;
 419                 if (signal_pending(current))
 420                         break;
 421                 schedule();
 422         }
 423         set_current_state(TASK_RUNNING);
 424         remove_wait_queue(&pf->rwait, &wait);
 425
 426         if (skb == 0)
 427                 goto out;
 428
 429         ret = -EOVERFLOW;
 430         if (skb->len > count)
 431                 goto outf;
 432         ret = -EFAULT;
 433         if (copy_to_user(buf, skb->data, skb->len))
 434                 goto outf;
 435         ret = skb->len;
 436
 437  outf:
 438         kfree_skb(skb);
 439  out:
 440         return ret;
 441 }
 442
 443 static ssize_t ppp_write(struct file *file, const char __user *buf,
 444                          size_t count, loff_t *ppos)
 445 {
 446         struct ppp_file *pf = file->private_data;
 447         struct sk_buff *skb;
 448         ssize_t ret;
 449
 450         if (pf == 0)
 451                 return -ENXIO;
 452         ret = -ENOMEM;
 453         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 454         if (skb == 0)
 455                 goto out;
 456         skb_reserve(skb, pf->hdrlen);
 457         ret = -EFAULT;
 458         if (copy_from_user(skb_put(skb, count), buf, count)) {
 459                 kfree_skb(skb);
 460                 goto out;
 461         }
 462
 463         skb_queue_tail(&pf->xq, skb);
 464
 465         switch (pf->kind) {
 466         case INTERFACE:
 467                 ppp_xmit_process(PF_TO_PPP(pf));
 468                 break;
 469         case CHANNEL:
 470                 ppp_channel_push(PF_TO_CHANNEL(pf));
 471                 break;
 472         }
 473
 474         ret = count;
 475
 476  out:
 477         return ret;
 478 }
 479
 480 /* No kernel lock - fine */
 481 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 482 {
 483         struct ppp_file *pf = file->private_data;
 484         unsigned int mask;
 485
 486         if (pf == 0)
 487                 return 0;
 488         poll_wait(file, &pf->rwait, wait);
 489         mask = POLLOUT | POLLWRNORM;
 490         if (skb_peek(&pf->rq) != 0)
 491                 mask |= POLLIN | POLLRDNORM;
 492         if (pf->dead)
 493                 mask |= POLLHUP;
 494         return mask;
 495 }
 496
 497 #ifdef CONFIG_PPP_FILTER
 498 static int get_filter(void __user *arg, struct sock_filter **p)
 499 {
 500         struct sock_fprog uprog;
 501         struct sock_filter *code = NULL;
 502         int len, err;
 503
 504         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 505                 return -EFAULT;
 506
 507         if (uprog.len > BPF_MAXINSNS)
 508                 return -EINVAL;
 509
 510         if (!uprog.len) {
 511                 *p = NULL;
 512                 return 0;
 513         }
 514
 515         len = uprog.len * sizeof(struct sock_filter);
 516         code = kmalloc(len, GFP_KERNEL);
 517         if (code == NULL)
 518                 return -ENOMEM;
 519
 520         if (copy_from_user(code, uprog.filter, len)) {
 521                 kfree(code);
 522                 return -EFAULT;
 523         }
 524
 525         err = sk_chk_filter(code, uprog.len);
 526         if (err) {
 527                 kfree(code);
 528                 return err;
 529         }
 530
 531         *p = code;
 532         return uprog.len;
 533 }
 534 #endif /* CONFIG_PPP_FILTER */
 535
 536 static int ppp_ioctl(struct inode *inode, struct file *file,
 537                      unsigned int cmd, unsigned long arg)
 538 {
 539         struct ppp_file *pf = file->private_data;
 540         struct ppp *ppp;
 541         int err = -EFAULT, val, val2, i;
 542         struct ppp_idle idle;
 543         struct npioctl npi;
 544         int unit, cflags;
 545         struct slcompress *vj;
 546         void __user *argp = (void __user *)arg;
 547         int __user *p = argp;
 548
 549         if (pf == 0)
 550                 return ppp_unattached_ioctl(pf, file, cmd, arg);
 551
 552         if (cmd == PPPIOCDETACH) {
 553                 /*
 554                  * We have to be careful here... if the file descriptor
 555                  * has been dup'd, we could have another process in the
 556                  * middle of a poll using the same file *, so we had
 557                  * better not free the interface data structures -
 558                  * instead we fail the ioctl.  Even in this case, we
 559                  * shut down the interface if we are the owner of it.
 560                  * Actually, we should get rid of PPPIOCDETACH, userland
 561                  * (i.e. pppd) could achieve the same effect by closing
 562                  * this fd and reopening /dev/ppp.
 563                  */
 564                 err = -EINVAL;
 565                 if (pf->kind == INTERFACE) {
 566                         ppp = PF_TO_PPP(pf);
 567                         if (file == ppp->owner)
 568                                 ppp_shutdown_interface(ppp);
 569                 }
 570                 if (atomic_read(&file->f_count) <= 2) {
 571                         ppp_release(inode, file);
 572                         err = 0;
 573                 } else
 574                         printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%d\n",
 575                                atomic_read(&file->f_count));
 576                 return err;
 577         }
 578
 579         if (pf->kind == CHANNEL) {
 580                 struct channel *pch = PF_TO_CHANNEL(pf);
 581                 struct ppp_channel *chan;
 582
 583                 switch (cmd) {
 584                 case PPPIOCCONNECT:
 585                         if (get_user(unit, p))
 586                                 break;
 587                         err = ppp_connect_channel(pch, unit);
 588                         break;
 589
 590                 case PPPIOCDISCONN:
 591                         err = ppp_disconnect_channel(pch);
 592                         break;
 593
 594                 default:
 595                         down_read(&pch->chan_sem);
 596                         chan = pch->chan;
 597                         err = -ENOTTY;
 598                         if (chan && chan->ops->ioctl)
 599                                 err = chan->ops->ioctl(chan, cmd, arg);
 600                         up_read(&pch->chan_sem);
 601                 }
 602                 return err;
 603         }
 604
 605         if (pf->kind != INTERFACE) {
 606                 /* can't happen */
 607                 printk(KERN_ERR "PPP: not interface or channel??\n");
 608                 return -EINVAL;
 609         }
 610
 611         ppp = PF_TO_PPP(pf);
 612         switch (cmd) {
 613         case PPPIOCSMRU:
 614                 if (get_user(val, p))
 615                         break;
 616                 ppp->mru = val;
 617                 err = 0;
 618                 break;
 619
 620         case PPPIOCSFLAGS:
 621                 if (get_user(val, p))
 622                         break;
 623                 ppp_lock(ppp);
 624                 cflags = ppp->flags & ~val;
 625                 ppp->flags = val & SC_FLAG_BITS;
 626                 ppp_unlock(ppp);
 627                 if (cflags & SC_CCP_OPEN)
 628                         ppp_ccp_closed(ppp);
 629                 err = 0;
 630                 break;
 631
 632         case PPPIOCGFLAGS:
 633                 val = ppp->flags | ppp->xstate | ppp->rstate;
 634                 if (put_user(val, p))
 635                         break;
 636                 err = 0;
 637                 break;
 638
 639         case PPPIOCSCOMPRESS:
 640                 err = ppp_set_compress(ppp, arg);
 641                 break;
 642
 643         case PPPIOCGUNIT:
 644                 if (put_user(ppp->file.index, p))
 645                         break;
 646                 err = 0;
 647                 break;
 648
 649         case PPPIOCSDEBUG:
 650                 if (get_user(val, p))
 651                         break;
 652                 ppp->debug = val;
 653                 err = 0;
 654                 break;
 655
 656         case PPPIOCGDEBUG:
 657                 if (put_user(ppp->debug, p))
 658                         break;
 659                 err = 0;
 660                 break;
 661
 662         case PPPIOCGIDLE:
 663                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 664                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 665                 if (copy_to_user(argp, &idle, sizeof(idle)))
 666                         break;
 667                 err = 0;
 668                 break;
 669
 670         case PPPIOCSMAXCID:
 671                 if (get_user(val, p))
 672                         break;
 673                 val2 = 15;
 674                 if ((val >> 16) != 0) {
 675                         val2 = val >> 16;
 676                         val &= 0xffff;
 677                 }
 678                 vj = slhc_init(val2+1, val+1);
 679                 if (vj == 0) {
 680                         printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
 681                         err = -ENOMEM;
 682                         break;
 683                 }
 684                 ppp_lock(ppp);
 685                 if (ppp->vj != 0)
 686                         slhc_free(ppp->vj);
 687                 ppp->vj = vj;
 688                 ppp_unlock(ppp);
 689                 err = 0;
 690                 break;
 691
 692         case PPPIOCGNPMODE:
 693         case PPPIOCSNPMODE:
 694                 if (copy_from_user(&npi, argp, sizeof(npi)))
 695                         break;
 696                 err = proto_to_npindex(npi.protocol);
 697                 if (err < 0)
 698                         break;
 699                 i = err;
 700                 if (cmd == PPPIOCGNPMODE) {
 701                         err = -EFAULT;
 702                         npi.mode = ppp->npmode[i];
 703                         if (copy_to_user(argp, &npi, sizeof(npi)))
 704                                 break;
 705                 } else {
 706                         ppp->npmode[i] = npi.mode;
 707                         /* we may be able to transmit more packets now (??) */
 708                         netif_wake_queue(ppp->dev);
 709                 }
 710                 err = 0;
 711                 break;
 712
 713 #ifdef CONFIG_PPP_FILTER
 714         case PPPIOCSPASS:
 715         {
 716                 struct sock_filter *code;
 717                 err = get_filter(argp, &code);
 718                 if (err >= 0) {
 719                         ppp_lock(ppp);
 720                         kfree(ppp->pass_filter);
 721                         ppp->pass_filter = code;
 722                         ppp->pass_len = err;
 723                         ppp_unlock(ppp);
 724                         err = 0;
 725                 }
 726                 break;
 727         }
 728         case PPPIOCSACTIVE:
 729         {
 730                 struct sock_filter *code;
 731                 err = get_filter(argp, &code);
 732                 if (err >= 0) {
 733                         ppp_lock(ppp);
 734                         kfree(ppp->active_filter);
 735                         ppp->active_filter = code;
 736                         ppp->active_len = err;
 737                         ppp_unlock(ppp);
 738                         err = 0;
 739                 }
 740                 break;
 741         }
 742 #endif /* CONFIG_PPP_FILTER */
 743
 744 #ifdef CONFIG_PPP_MULTILINK
 745         case PPPIOCSMRRU:
 746                 if (get_user(val, p))
 747                         break;
 748                 ppp_recv_lock(ppp);
 749                 ppp->mrru = val;
 750                 ppp_recv_unlock(ppp);
 751                 err = 0;
 752                 break;
 753 #endif /* CONFIG_PPP_MULTILINK */
 754
 755         default:
 756                 err = -ENOTTY;
 757         }
 758
 759         return err;
 760 }
 761
 762 static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
 763                                 unsigned int cmd, unsigned long arg)
 764 {
 765         int unit, err = -EFAULT;
 766         struct ppp *ppp;
 767         struct channel *chan;
 768         int __user *p = (int __user *)arg;
 769
 770         switch (cmd) {
 771         case PPPIOCNEWUNIT:
 772                 /* Create a new ppp unit */
 773                 if (get_user(unit, p))
 774                         break;
 775                 ppp = ppp_create_interface(unit, &err);
 776                 if (ppp == 0)
 777                         break;
 778                 file->private_data = &ppp->file;
 779                 ppp->owner = file;
 780                 err = -EFAULT;
 781                 if (put_user(ppp->file.index, p))
 782                         break;
 783                 err = 0;
 784                 break;
 785
 786         case PPPIOCATTACH:
 787                 /* Attach to an existing ppp unit */
 788                 if (get_user(unit, p))
 789                         break;
 790                 down(&all_ppp_sem);
 791                 err = -ENXIO;
 792                 ppp = ppp_find_unit(unit);
 793                 if (ppp != 0) {
 794                         atomic_inc(&ppp->file.refcnt);
 795                         file->private_data = &ppp->file;
 796                         err = 0;
 797                 }
 798                 up(&all_ppp_sem);
 799                 break;
 800
 801         case PPPIOCATTCHAN:
 802                 if (get_user(unit, p))
 803                         break;
 804                 spin_lock_bh(&all_channels_lock);
 805                 err = -ENXIO;
 806                 chan = ppp_find_channel(unit);
 807                 if (chan != 0) {
 808                         atomic_inc(&chan->file.refcnt);
 809                         file->private_data = &chan->file;
 810                         err = 0;
 811                 }
 812                 spin_unlock_bh(&all_channels_lock);
 813                 break;
 814
 815         default:
 816                 err = -ENOTTY;
 817         }
 818         return err;
 819 }
 820
 821 static struct file_operations ppp_device_fops = {
 822         .owner          = THIS_MODULE,
 823         .read           = ppp_read,
 824         .write          = ppp_write,
 825         .poll           = ppp_poll,
 826         .ioctl          = ppp_ioctl,
 827         .open           = ppp_open,
 828         .release        = ppp_release
 829 };
 830
 831 #define PPP_MAJOR       108
 832
 833 /* Called at boot time if ppp is compiled into the kernel,
 834    or at module load time (from init_module) if compiled as a module. */
 835 static int __init ppp_init(void)
 836 {
 837         int err;
 838
 839         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
 840         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 841         if (!err) {
 842                 ppp_class = class_simple_create(THIS_MODULE, "ppp");
 843                 if (IS_ERR(ppp_class)) {
 844                         err = PTR_ERR(ppp_class);
 845                         goto out_chrdev;
 846                 }
 847                 class_simple_device_add(ppp_class, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 848                 err = devfs_mk_cdev(MKDEV(PPP_MAJOR, 0),
 849                                 S_IFCHR|S_IRUSR|S_IWUSR, "ppp");
 850                 if (err)
 851                         goto out_class;
 852         }
 853
 854 out:
 855         if (err)
 856                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
 857         return err;
 858
 859 out_class:
 860         class_simple_device_remove(MKDEV(PPP_MAJOR,0));
 861         class_simple_destroy(ppp_class);
 862 out_chrdev:
 863         unregister_chrdev(PPP_MAJOR, "ppp");
 864         goto out;
 865 }
 866
 867 /*
 868  * Network interface unit routines.
 869  */
 870 static int
 871 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 872 {
 873         struct ppp *ppp = (struct ppp *) dev->priv;
 874         int npi, proto;
 875         unsigned char *pp;
 876
 877         npi = ethertype_to_npindex(ntohs(skb->protocol));
 878         if (npi < 0)
 879                 goto outf;
 880
 881         /* Drop, accept or reject the packet */
 882         switch (ppp->npmode[npi]) {
 883         case NPMODE_PASS:
 884                 break;
 885         case NPMODE_QUEUE:
 886                 /* it would be nice to have a way to tell the network
 887                    system to queue this one up for later. */
 888                 goto outf;
 889         case NPMODE_DROP:
 890         case NPMODE_ERROR:
 891                 goto outf;
 892         }
 893
 894         /* Put the 2-byte PPP protocol number on the front,
 895            making sure there is room for the address and control fields. */
 896         if (skb_headroom(skb) < PPP_HDRLEN) {
 897                 struct sk_buff *ns;
 898
 899                 ns = alloc_skb(skb->len + dev->hard_header_len, GFP_ATOMIC);
 900                 if (ns == 0)
 901                         goto outf;
 902                 skb_reserve(ns, dev->hard_header_len);
 903                 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
 904                 kfree_skb(skb);
 905                 skb = ns;
 906         }
 907         pp = skb_push(skb, 2);
 908         proto = npindex_to_proto[npi];
 909         pp[0] = proto >> 8;
 910         pp[1] = proto;
 911
 912         netif_stop_queue(dev);
 913         skb_queue_tail(&ppp->file.xq, skb);
 914         ppp_xmit_process(ppp);
 915         return 0;
 916
 917  outf:
 918         kfree_skb(skb);
 919         ++ppp->stats.tx_dropped;
 920         return 0;
 921 }
 922
 923 static struct net_device_stats *
 924 ppp_net_stats(struct net_device *dev)
 925 {
 926         struct ppp *ppp = (struct ppp *) dev->priv;
 927
 928         return &ppp->stats;
 929 }
 930
 931 static int
 932 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 933 {
 934         struct ppp *ppp = dev->priv;
 935         int err = -EFAULT;
 936         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
 937         struct ppp_stats stats;
 938         struct ppp_comp_stats cstats;
 939         char *vers;
 940
 941         switch (cmd) {
 942         case SIOCGPPPSTATS:
 943                 ppp_get_stats(ppp, &stats);
 944                 if (copy_to_user(addr, &stats, sizeof(stats)))
 945                         break;
 946                 err = 0;
 947                 break;
 948
 949         case SIOCGPPPCSTATS:
 950                 memset(&cstats, 0, sizeof(cstats));
 951                 if (ppp->xc_state != 0)
 952                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
 953                 if (ppp->rc_state != 0)
 954                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
 955                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
 956                         break;
 957                 err = 0;
 958                 break;
 959
 960         case SIOCGPPPVER:
 961                 vers = PPP_VERSION;
 962                 if (copy_to_user(addr, vers, strlen(vers) + 1))
 963                         break;
 964                 err = 0;
 965                 break;
 966
 967         default:
 968                 err = -EINVAL;
 969         }
 970
 971         return err;
 972 }
 973
 974 static void ppp_setup(struct net_device *dev)
 975 {
 976         dev->hard_header_len = PPP_HDRLEN;
 977         dev->mtu = PPP_MTU;
 978         dev->addr_len = 0;
 979         dev->tx_queue_len = 3;
 980         dev->type = ARPHRD_PPP;
 981         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 982 }
 983
 984 /*
 985  * Transmit-side routines.
 986  */
 987
 988 /*
 989  * Called to do any work queued up on the transmit side
 990  * that can now be done.
 991  */
 992 static void
 993 ppp_xmit_process(struct ppp *ppp)
 994 {
 995         struct sk_buff *skb;
 996
 997         ppp_xmit_lock(ppp);
 998         if (ppp->dev != 0) {
 999                 ppp_push(ppp);
1000                 while (ppp->xmit_pending == 0
1001                        && (skb = skb_dequeue(&ppp->file.xq)) != 0)
1002                         ppp_send_frame(ppp, skb);
1003                 /* If there's no work left to do, tell the core net
1004                    code that we can accept some more. */
1005                 if (ppp->xmit_pending == 0 && skb_peek(&ppp->file.xq) == 0)
1006                         netif_wake_queue(ppp->dev);
1007         }
1008         ppp_xmit_unlock(ppp);
1009 }
1010
1011 /*
1012  * Compress and send a frame.
1013  * The caller should have locked the xmit path,
1014  * and xmit_pending should be 0.
1015  */
1016 static void
1017 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1018 {
1019         int proto = PPP_PROTO(skb);
1020         struct sk_buff *new_skb;
1021         int len;
1022         unsigned char *cp;
1023
1024         if (proto < 0x8000) {
1025 #ifdef CONFIG_PPP_FILTER
1026                 /* check if we should pass this packet */
1027                 /* the filter instructions are constructed assuming
1028                    a four-byte PPP header on each packet */
1029                 *skb_push(skb, 2) = 1;
1030                 if (ppp->pass_filter
1031                     && sk_run_filter(skb, ppp->pass_filter,
1032                                      ppp->pass_len) == 0) {
1033                         if (ppp->debug & 1)
1034                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1035                         kfree_skb(skb);
1036                         return;
1037                 }
1038                 /* if this packet passes the active filter, record the time */
1039                 if (!(ppp->active_filter
1040                       && sk_run_filter(skb, ppp->active_filter,
1041                                        ppp->active_len) == 0))
1042                         ppp->last_xmit = jiffies;
1043                 skb_pull(skb, 2);
1044 #else
1045                 /* for data packets, record the time */
1046                 ppp->last_xmit = jiffies;
1047 #endif /* CONFIG_PPP_FILTER */
1048         }
1049
1050         ++ppp->stats.tx_packets;
1051         ppp->stats.tx_bytes += skb->len - 2;
1052
1053         switch (proto) {
1054         case PPP_IP:
1055                 if (ppp->vj == 0 || (ppp->flags & SC_COMP_TCP) == 0)
1056                         break;
1057                 /* try to do VJ TCP header compression */
1058                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1059                                     GFP_ATOMIC);
1060                 if (new_skb == 0) {
1061                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1062                         goto drop;
1063                 }
1064                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1065                 cp = skb->data + 2;
1066                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1067                                     new_skb->data + 2, &cp,
1068                                     !(ppp->flags & SC_NO_TCP_CCID));
1069                 if (cp == skb->data + 2) {
1070                         /* didn't compress */
1071                         kfree_skb(new_skb);
1072                 } else {
1073                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1074                                 proto = PPP_VJC_COMP;
1075                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1076                         } else {
1077                                 proto = PPP_VJC_UNCOMP;
1078                                 cp[0] = skb->data[2];
1079                         }
1080                         kfree_skb(skb);
1081                         skb = new_skb;
1082                         cp = skb_put(skb, len + 2);
1083                         cp[0] = 0;
1084                         cp[1] = proto;
1085                 }
1086                 break;
1087
1088         case PPP_CCP:
1089                 /* peek at outbound CCP frames */
1090                 ppp_ccp_peek(ppp, skb, 0);
1091                 break;
1092         }
1093
1094         /* try to do packet compression */
1095         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0
1096             && proto != PPP_LCP && proto != PPP_CCP) {
1097                 new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len,
1098                                     GFP_ATOMIC);
1099                 if (new_skb == 0) {
1100                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1101                         goto drop;
1102                 }
1103                 if (ppp->dev->hard_header_len > PPP_HDRLEN)
1104                         skb_reserve(new_skb,
1105                                     ppp->dev->hard_header_len - PPP_HDRLEN);
1106
1107                 /* compressor still expects A/C bytes in hdr */
1108                 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1109                                            new_skb->data, skb->len + 2,
1110                                            ppp->dev->mtu + PPP_HDRLEN);
1111                 if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1112                         kfree_skb(skb);
1113                         skb = new_skb;
1114                         skb_put(skb, len);
1115                         skb_pull(skb, 2);       /* pull off A/C bytes */
1116                 } else {
1117                         /* didn't compress, or CCP not up yet */
1118                         kfree_skb(new_skb);
1119                 }
1120         }
1121
1122         /*
1123          * If we are waiting for traffic (demand dialling),
1124          * queue it up for pppd to receive.
1125          */
1126         if (ppp->flags & SC_LOOP_TRAFFIC) {
1127                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1128                         goto drop;
1129                 skb_queue_tail(&ppp->file.rq, skb);
1130                 wake_up_interruptible(&ppp->file.rwait);
1131                 return;
1132         }
1133
1134         ppp->xmit_pending = skb;
1135         ppp_push(ppp);
1136         return;
1137
1138  drop:
1139         kfree_skb(skb);
1140         ++ppp->stats.tx_errors;
1141 }
1142
1143 /*
1144  * Try to send the frame in xmit_pending.
1145  * The caller should have the xmit path locked.
1146  */
1147 static void
1148 ppp_push(struct ppp *ppp)
1149 {
1150         struct list_head *list;
1151         struct channel *pch;
1152         struct sk_buff *skb = ppp->xmit_pending;
1153
1154         if (skb == 0)
1155                 return;
1156
1157         list = &ppp->channels;
1158         if (list_empty(list)) {
1159                 /* nowhere to send the packet, just drop it */
1160                 ppp->xmit_pending = NULL;
1161                 kfree_skb(skb);
1162                 return;
1163         }
1164
1165         if ((ppp->flags & SC_MULTILINK) == 0) {
1166                 /* not doing multilink: send it down the first channel */
1167                 list = list->next;
1168                 pch = list_entry(list, struct channel, clist);
1169
1170                 spin_lock_bh(&pch->downl);
1171                 if (pch->chan) {
1172                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1173                                 ppp->xmit_pending = NULL;
1174                 } else {
1175                         /* channel got unregistered */
1176                         kfree_skb(skb);
1177                         ppp->xmit_pending = NULL;
1178                 }
1179                 spin_unlock_bh(&pch->downl);
1180                 return;
1181         }
1182
1183 #ifdef CONFIG_PPP_MULTILINK
1184         /* Multilink: fragment the packet over as many links
1185            as can take the packet at the moment. */
1186         if (!ppp_mp_explode(ppp, skb))
1187                 return;
1188 #endif /* CONFIG_PPP_MULTILINK */
1189
1190         ppp->xmit_pending = NULL;
1191         kfree_skb(skb);
1192 }
1193
1194 #ifdef CONFIG_PPP_MULTILINK
1195 /*
1196  * Divide a packet to be transmitted into fragments and
1197  * send them out the individual links.
1198  */
1199 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1200 {
1201         int nch, len, fragsize;
1202         int i, bits, hdrlen, mtu;
1203         int flen, fnb;
1204         unsigned char *p, *q;
1205         struct list_head *list;
1206         struct channel *pch;
1207         struct sk_buff *frag;
1208         struct ppp_channel *chan;
1209
1210         nch = 0;
1211         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1212         list = &ppp->channels;
1213         while ((list = list->next) != &ppp->channels) {
1214                 pch = list_entry(list, struct channel, clist);
1215                 nch += pch->avail = (skb_queue_len(&pch->file.xq) == 0);
1216                 /*
1217                  * If a channel hasn't had a fragment yet, it has to get
1218                  * one before we send any fragments on later channels.
1219                  * If it can't take a fragment now, don't give any
1220                  * to subsequent channels.
1221                  */
1222                 if (!pch->had_frag && !pch->avail) {
1223                         while ((list = list->next) != &ppp->channels) {
1224                                 pch = list_entry(list, struct channel, clist);
1225                                 pch->avail = 0;
1226                         }
1227                         break;
1228                 }
1229         }
1230         if (nch == 0)
1231                 return 0;       /* can't take now, leave it in xmit_pending */
1232
1233         /* Do protocol field compression (XXX this should be optional) */
1234         p = skb->data;
1235         len = skb->len;
1236         if (*p == 0) {
1237                 ++p;
1238                 --len;
1239         }
1240
1241         /* decide on fragment size */
1242         fragsize = len;
1243         if (nch > 1) {
1244                 int maxch = ROUNDUP(len, MIN_FRAG_SIZE);
1245                 if (nch > maxch)
1246                         nch = maxch;
1247                 fragsize = ROUNDUP(fragsize, nch);
1248         }
1249
1250         /* skip to the channel after the one we last used
1251            and start at that one */
1252         for (i = 0; i < ppp->nxchan; ++i) {
1253                 list = list->next;
1254                 if (list == &ppp->channels) {
1255                         i = 0;
1256                         break;
1257                 }
1258         }
1259
1260         /* create a fragment for each channel */
1261         bits = B;
1262         do {
1263                 list = list->next;
1264                 if (list == &ppp->channels) {
1265                         i = 0;
1266                         continue;
1267                 }
1268                 pch = list_entry(list, struct channel, clist);
1269                 ++i;
1270                 if (!pch->avail)
1271                         continue;
1272
1273                 /* check the channel's mtu and whether it is still attached. */
1274                 spin_lock_bh(&pch->downl);
1275                 if (pch->chan == 0 || (mtu = pch->chan->mtu) < hdrlen) {
1276                         /* can't use this channel */
1277                         spin_unlock_bh(&pch->downl);
1278                         pch->avail = 0;
1279                         if (--nch == 0)
1280                                 break;
1281                         continue;
1282                 }
1283
1284                 /*
1285                  * We have to create multiple fragments for this channel
1286                  * if fragsize is greater than the channel's mtu.
1287                  */
1288                 if (fragsize > len)
1289                         fragsize = len;
1290                 for (flen = fragsize; flen > 0; flen -= fnb) {
1291                         fnb = flen;
1292                         if (fnb > mtu + 2 - hdrlen)
1293                                 fnb = mtu + 2 - hdrlen;
1294                         if (fnb >= len)
1295                                 bits |= E;
1296                         frag = alloc_skb(fnb + hdrlen, GFP_ATOMIC);
1297                         if (frag == 0)
1298                                 goto noskb;
1299                         q = skb_put(frag, fnb + hdrlen);
1300                         /* make the MP header */
1301                         q[0] = PPP_MP >> 8;
1302                         q[1] = PPP_MP;
1303                         if (ppp->flags & SC_MP_XSHORTSEQ) {
1304                                 q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1305                                 q[3] = ppp->nxseq;
1306                         } else {
1307                                 q[2] = bits;
1308                                 q[3] = ppp->nxseq >> 16;
1309                                 q[4] = ppp->nxseq >> 8;
1310                                 q[5] = ppp->nxseq;
1311                         }
1312
1313                         /* copy the data in */
1314                         memcpy(q + hdrlen, p, fnb);
1315
1316                         /* try to send it down the channel */
1317                         chan = pch->chan;
1318                         if (!chan->ops->start_xmit(chan, frag))
1319                                 skb_queue_tail(&pch->file.xq, frag);
1320                         pch->had_frag = 1;
1321                         p += fnb;
1322                         len -= fnb;
1323                         ++ppp->nxseq;
1324                         bits = 0;
1325                 }
1326                 spin_unlock_bh(&pch->downl);
1327         } while (len > 0);
1328         ppp->nxchan = i;
1329
1330         return 1;
1331
1332  noskb:
1333         spin_unlock_bh(&pch->downl);
1334         if (ppp->debug & 1)
1335                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1336         ++ppp->stats.tx_errors;
1337         ++ppp->nxseq;
1338         return 1;       /* abandon the frame */
1339 }
1340 #endif /* CONFIG_PPP_MULTILINK */
1341
1342 /*
1343  * Try to send data out on a channel.
1344  */
1345 static void
1346 ppp_channel_push(struct channel *pch)
1347 {
1348         struct sk_buff *skb;
1349         struct ppp *ppp;
1350
1351         spin_lock_bh(&pch->downl);
1352         if (pch->chan != 0) {
1353                 while (skb_queue_len(&pch->file.xq) > 0) {
1354                         skb = skb_dequeue(&pch->file.xq);
1355                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1356                                 /* put the packet back and try again later */
1357                                 skb_queue_head(&pch->file.xq, skb);
1358                                 break;
1359                         }
1360                 }
1361         } else {
1362                 /* channel got deregistered */
1363                 skb_queue_purge(&pch->file.xq);
1364         }
1365         spin_unlock_bh(&pch->downl);
1366         /* see if there is anything from the attached unit to be sent */
1367         if (skb_queue_len(&pch->file.xq) == 0) {
1368                 read_lock_bh(&pch->upl);
1369                 ppp = pch->ppp;
1370                 if (ppp != 0)
1371                         ppp_xmit_process(ppp);
1372                 read_unlock_bh(&pch->upl);
1373         }
1374 }
1375
1376 /*
1377  * Receive-side routines.
1378  */
1379
1380 /* misuse a few fields of the skb for MP reconstruction */
1381 #define sequence        priority
1382 #define BEbits          cb[0]
1383
1384 static inline void
1385 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1386 {
1387         ppp_recv_lock(ppp);
1388         /* ppp->dev == 0 means interface is closing down */
1389         if (ppp->dev != 0)
1390                 ppp_receive_frame(ppp, skb, pch);
1391         else
1392                 kfree_skb(skb);
1393         ppp_recv_unlock(ppp);
1394 }
1395
1396 void
1397 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1398 {
1399         struct channel *pch = chan->ppp;
1400         int proto;
1401
1402         if (pch == 0 || skb->len == 0) {
1403                 kfree_skb(skb);
1404                 return;
1405         }
1406
1407         proto = PPP_PROTO(skb);
1408         read_lock_bh(&pch->upl);
1409         if (pch->ppp == 0 || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1410                 /* put it on the channel queue */
1411                 skb_queue_tail(&pch->file.rq, skb);
1412                 /* drop old frames if queue too long */
1413                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1414                        && (skb = skb_dequeue(&pch->file.rq)) != 0)
1415                         kfree_skb(skb);
1416                 wake_up_interruptible(&pch->file.rwait);
1417         } else {
1418                 ppp_do_recv(pch->ppp, skb, pch);
1419         }
1420         read_unlock_bh(&pch->upl);
1421 }
1422
1423 /* Put a 0-length skb in the receive queue as an error indication */
1424 void
1425 ppp_input_error(struct ppp_channel *chan, int code)
1426 {
1427         struct channel *pch = chan->ppp;
1428         struct sk_buff *skb;
1429
1430         if (pch == 0)
1431                 return;
1432
1433         read_lock_bh(&pch->upl);
1434         if (pch->ppp != 0) {
1435                 skb = alloc_skb(0, GFP_ATOMIC);
1436                 if (skb != 0) {
1437                         skb->len = 0;           /* probably unnecessary */
1438                         skb->cb[0] = code;
1439                         ppp_do_recv(pch->ppp, skb, pch);
1440                 }
1441         }
1442         read_unlock_bh(&pch->upl);
1443 }
1444
1445 /*
1446  * We come in here to process a received frame.
1447  * The receive side of the ppp unit is locked.
1448  */
1449 static void
1450 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1451 {
1452         if (skb->len >= 2) {
1453 #ifdef CONFIG_PPP_MULTILINK
1454                 /* XXX do channel-level decompression here */
1455                 if (PPP_PROTO(skb) == PPP_MP)
1456                         ppp_receive_mp_frame(ppp, skb, pch);
1457                 else
1458 #endif /* CONFIG_PPP_MULTILINK */
1459                         ppp_receive_nonmp_frame(ppp, skb);
1460                 return;
1461         }
1462
1463         if (skb->len > 0)
1464                 /* note: a 0-length skb is used as an error indication */
1465                 ++ppp->stats.rx_length_errors;
1466
1467         kfree_skb(skb);
1468         ppp_receive_error(ppp);
1469 }
1470
1471 static void
1472 ppp_receive_error(struct ppp *ppp)
1473 {
1474         ++ppp->stats.rx_errors;
1475         if (ppp->vj != 0)
1476                 slhc_toss(ppp->vj);
1477 }
1478
1479 static void
1480 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1481 {
1482         struct sk_buff *ns;
1483         int proto, len, npi;
1484
1485         /*
1486          * Decompress the frame, if compressed.
1487          * Note that some decompressors need to see uncompressed frames
1488          * that come in as well as compressed frames.
1489          */
1490         if (ppp->rc_state != 0 && (ppp->rstate & SC_DECOMP_RUN)
1491             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1492                 skb = ppp_decompress_frame(ppp, skb);
1493
1494         proto = PPP_PROTO(skb);
1495         switch (proto) {
1496         case PPP_VJC_COMP:
1497                 /* decompress VJ compressed packets */
1498                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1499                         goto err;
1500
1501                 if (skb_tailroom(skb) < 124) {
1502                         /* copy to a new sk_buff with more tailroom */
1503                         ns = dev_alloc_skb(skb->len + 128);
1504                         if (ns == 0) {
1505                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1506                                 goto err;
1507                         }
1508                         skb_reserve(ns, 2);
1509                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1510                         kfree_skb(skb);
1511                         skb = ns;
1512                 }
1513                 else if (!pskb_may_pull(skb, skb->len))
1514                         goto err;
1515
1516                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1517                 if (len <= 0) {
1518                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1519                         goto err;
1520                 }
1521                 len += 2;
1522                 if (len > skb->len)
1523                         skb_put(skb, len - skb->len);
1524                 else if (len < skb->len)
1525                         skb_trim(skb, len);
1526                 proto = PPP_IP;
1527                 break;
1528
1529         case PPP_VJC_UNCOMP:
1530                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1531                         goto err;
1532
1533                 /* Until we fix the decompressor need to make sure
1534                  * data portion is linear.
1535                  */
1536                 if (!pskb_may_pull(skb, skb->len))
1537                         goto err;
1538
1539                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1540                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1541                         goto err;
1542                 }
1543                 proto = PPP_IP;
1544                 break;
1545
1546         case PPP_CCP:
1547                 ppp_ccp_peek(ppp, skb, 1);
1548                 break;
1549         }
1550
1551         ++ppp->stats.rx_packets;
1552         ppp->stats.rx_bytes += skb->len - 2;
1553
1554         npi = proto_to_npindex(proto);
1555         if (npi < 0) {
1556                 /* control or unknown frame - pass it to pppd */
1557                 skb_queue_tail(&ppp->file.rq, skb);
1558                 /* limit queue length by dropping old frames */
1559                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1560                        && (skb = skb_dequeue(&ppp->file.rq)) != 0)
1561                         kfree_skb(skb);
1562                 /* wake up any process polling or blocking on read */
1563                 wake_up_interruptible(&ppp->file.rwait);
1564
1565         } else {
1566                 /* network protocol frame - give it to the kernel */
1567
1568 #ifdef CONFIG_PPP_FILTER
1569                 /* check if the packet passes the pass and active filters */
1570                 /* the filter instructions are constructed assuming
1571                    a four-byte PPP header on each packet */
1572                 *skb_push(skb, 2) = 0;
1573                 if (ppp->pass_filter
1574                     && sk_run_filter(skb, ppp->pass_filter,
1575                                      ppp->pass_len) == 0) {
1576                         if (ppp->debug & 1)
1577                                 printk(KERN_DEBUG "PPP: inbound frame not passed\n");
1578                         kfree_skb(skb);
1579                         return;
1580                 }
1581                 if (!(ppp->active_filter
1582                       && sk_run_filter(skb, ppp->active_filter,
1583                                        ppp->active_len) == 0))
1584                         ppp->last_recv = jiffies;
1585                 skb_pull(skb, 2);
1586 #else
1587                 ppp->last_recv = jiffies;
1588 #endif /* CONFIG_PPP_FILTER */
1589
1590                 if ((ppp->dev->flags & IFF_UP) == 0
1591                     || ppp->npmode[npi] != NPMODE_PASS) {
1592                         kfree_skb(skb);
1593                 } else {
1594                         skb_pull(skb, 2);       /* chop off protocol */
1595                         skb->dev = ppp->dev;
1596                         skb->protocol = htons(npindex_to_ethertype[npi]);
1597                         skb->mac.raw = skb->data;
1598                         skb->input_dev = ppp->dev;
1599                         netif_rx(skb);
1600                         ppp->dev->last_rx = jiffies;
1601                 }
1602         }
1603         return;
1604
1605  err:
1606         kfree_skb(skb);
1607         ppp_receive_error(ppp);
1608 }
1609
1610 static struct sk_buff *
1611 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1612 {
1613         int proto = PPP_PROTO(skb);
1614         struct sk_buff *ns;
1615         int len;
1616
1617         /* Until we fix all the decompressor's need to make sure
1618          * data portion is linear.
1619          */
1620         if (!pskb_may_pull(skb, skb->len))
1621                 goto err;
1622
1623         if (proto == PPP_COMP) {
1624                 ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN);
1625                 if (ns == 0) {
1626                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1627                         goto err;
1628                 }
1629                 /* the decompressor still expects the A/C bytes in the hdr */
1630                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1631                                 skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN);
1632                 if (len < 0) {
1633                         /* Pass the compressed frame to pppd as an
1634                            error indication. */
1635                         if (len == DECOMP_FATALERROR)
1636                                 ppp->rstate |= SC_DC_FERROR;
1637                         kfree_skb(ns);
1638                         goto err;
1639                 }
1640
1641                 kfree_skb(skb);
1642                 skb = ns;
1643                 skb_put(skb, len);
1644                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1645
1646         } else {
1647                 /* Uncompressed frame - pass to decompressor so it
1648                    can update its dictionary if necessary. */
1649                 if (ppp->rcomp->incomp)
1650                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1651                                            skb->len + 2);
1652         }
1653
1654         return skb;
1655
1656  err:
1657         ppp->rstate |= SC_DC_ERROR;
1658         ppp_receive_error(ppp);
1659         return skb;
1660 }
1661
1662 #ifdef CONFIG_PPP_MULTILINK
1663 /*
1664  * Receive a multilink frame.
1665  * We put it on the reconstruction queue and then pull off
1666  * as many completed frames as we can.
1667  */
1668 static void
1669 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1670 {
1671         u32 mask, seq;
1672         struct list_head *l;
1673         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1674
1675         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1676                 goto err;               /* no good, throw it away */
1677
1678         /* Decode sequence number and begin/end bits */
1679         if (ppp->flags & SC_MP_SHORTSEQ) {
1680                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1681                 mask = 0xfff;
1682         } else {
1683                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1684                 mask = 0xffffff;
1685         }
1686         skb->BEbits = skb->data[2];
1687         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1688
1689         /*
1690          * Do protocol ID decompression on the first fragment of each packet.
1691          */
1692         if ((skb->BEbits & B) && (skb->data[0] & 1))
1693                 *skb_push(skb, 1) = 0;
1694
1695         /*
1696          * Expand sequence number to 32 bits, making it as close
1697          * as possible to ppp->minseq.
1698          */
1699         seq |= ppp->minseq & ~mask;
1700         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1701                 seq += mask + 1;
1702         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1703                 seq -= mask + 1;        /* should never happen */
1704         skb->sequence = seq;
1705         pch->lastseq = seq;
1706
1707         /*
1708          * If this packet comes before the next one we were expecting,
1709          * drop it.
1710          */
1711         if (seq_before(seq, ppp->nextseq)) {
1712                 kfree_skb(skb);
1713                 ++ppp->stats.rx_dropped;
1714                 ppp_receive_error(ppp);
1715                 return;
1716         }
1717
1718         /*
1719          * Reevaluate minseq, the minimum over all channels of the
1720          * last sequence number received on each channel.  Because of
1721          * the increasing sequence number rule, we know that any fragment
1722          * before `minseq' which hasn't arrived is never going to arrive.
1723          * The list of channels can't change because we have the receive
1724          * side of the ppp unit locked.
1725          */
1726         for (l = ppp->channels.next; l != &ppp->channels; l = l->next) {
1727                 struct channel *ch = list_entry(l, struct channel, clist);
1728                 if (seq_before(ch->lastseq, seq))
1729                         seq = ch->lastseq;
1730         }
1731         if (seq_before(ppp->minseq, seq))
1732                 ppp->minseq = seq;
1733
1734         /* Put the fragment on the reconstruction queue */
1735         ppp_mp_insert(ppp, skb);
1736
1737         /* If the queue is getting long, don't wait any longer for packets
1738            before the start of the queue. */
1739         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN
1740             && seq_before(ppp->minseq, ppp->mrq.next->sequence))
1741                 ppp->minseq = ppp->mrq.next->sequence;
1742
1743         /* Pull completed packets off the queue and receive them. */
1744         while ((skb = ppp_mp_reconstruct(ppp)) != 0)
1745                 ppp_receive_nonmp_frame(ppp, skb);
1746
1747         return;
1748
1749  err:
1750         kfree_skb(skb);
1751         ppp_receive_error(ppp);
1752 }
1753
1754 /*
1755  * Insert a fragment on the MP reconstruction queue.
1756  * The queue is ordered by increasing sequence number.
1757  */
1758 static void
1759 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1760 {
1761         struct sk_buff *p;
1762         struct sk_buff_head *list = &ppp->mrq;
1763         u32 seq = skb->sequence;
1764
1765         /* N.B. we don't need to lock the list lock because we have the
1766            ppp unit receive-side lock. */
1767         for (p = list->next; p != (struct sk_buff *)list; p = p->next)
1768                 if (seq_before(seq, p->sequence))
1769                         break;
1770         __skb_insert(skb, p->prev, p, list);
1771 }
1772
1773 /*
1774  * Reconstruct a packet from the MP fragment queue.
1775  * We go through increasing sequence numbers until we find a
1776  * complete packet, or we get to the sequence number for a fragment
1777  * which hasn't arrived but might still do so.
1778  */
1779 struct sk_buff *
1780 ppp_mp_reconstruct(struct ppp *ppp)
1781 {
1782         u32 seq = ppp->nextseq;
1783         u32 minseq = ppp->minseq;
1784         struct sk_buff_head *list = &ppp->mrq;
1785         struct sk_buff *p, *next;
1786         struct sk_buff *head, *tail;
1787         struct sk_buff *skb = NULL;
1788         int lost = 0, len = 0;
1789
1790         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1791                 return NULL;
1792         head = list->next;
1793         tail = NULL;
1794         for (p = head; p != (struct sk_buff *) list; p = next) {
1795                 next = p->next;
1796                 if (seq_before(p->sequence, seq)) {
1797                         /* this can't happen, anyway ignore the skb */
1798                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1799                                p->sequence, seq);
1800                         head = next;
1801                         continue;
1802                 }
1803                 if (p->sequence != seq) {
1804                         /* Fragment `seq' is missing.  If it is after
1805                            minseq, it might arrive later, so stop here. */
1806                         if (seq_after(seq, minseq))
1807                                 break;
1808                         /* Fragment `seq' is lost, keep going. */
1809                         lost = 1;
1810                         seq = seq_before(minseq, p->sequence)?
1811                                 minseq + 1: p->sequence;
1812                         next = p;
1813                         continue;
1814                 }
1815
1816                 /*
1817                  * At this point we know that all the fragments from
1818                  * ppp->nextseq to seq are either present or lost.
1819                  * Also, there are no complete packets in the queue
1820                  * that have no missing fragments and end before this
1821                  * fragment.
1822                  */
1823
1824                 /* B bit set indicates this fragment starts a packet */
1825                 if (p->BEbits & B) {
1826                         head = p;
1827                         lost = 0;
1828                         len = 0;
1829                 }
1830
1831                 len += p->len;
1832
1833                 /* Got a complete packet yet? */
1834                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
1835                         if (len > ppp->mrru + 2) {
1836                                 ++ppp->stats.rx_length_errors;
1837                                 printk(KERN_DEBUG "PPP: reconstructed packet"
1838                                        " is too long (%d)\n", len);
1839                         } else if (p == head) {
1840                                 /* fragment is complete packet - reuse skb */
1841                                 tail = p;
1842                                 skb = skb_get(p);
1843                                 break;
1844                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
1845                                 ++ppp->stats.rx_missed_errors;
1846                                 printk(KERN_DEBUG "PPP: no memory for "
1847                                        "reconstructed packet");
1848                         } else {
1849                                 tail = p;
1850                                 break;
1851                         }
1852                         ppp->nextseq = seq + 1;
1853                 }
1854
1855                 /*
1856                  * If this is the ending fragment of a packet,
1857                  * and we haven't found a complete valid packet yet,
1858                  * we can discard up to and including this fragment.
1859                  */
1860                 if (p->BEbits & E)
1861                         head = next;
1862
1863                 ++seq;
1864         }
1865
1866         /* If we have a complete packet, copy it all into one skb. */
1867         if (tail != NULL) {
1868                 /* If we have discarded any fragments,
1869                    signal a receive error. */
1870                 if (head->sequence != ppp->nextseq) {
1871                         if (ppp->debug & 1)
1872                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
1873                                        ppp->nextseq, head->sequence-1);
1874                         ++ppp->stats.rx_dropped;
1875                         ppp_receive_error(ppp);
1876                 }
1877
1878                 if (head != tail)
1879                         /* copy to a single skb */
1880                         for (p = head; p != tail->next; p = p->next)
1881                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
1882                 ppp->nextseq = tail->sequence + 1;
1883                 head = tail->next;
1884         }
1885
1886         /* Discard all the skbuffs that we have copied the data out of
1887            or that we can't use. */
1888         while ((p = list->next) != head) {
1889                 __skb_unlink(p, list);
1890                 kfree_skb(p);
1891         }
1892
1893         return skb;
1894 }
1895 #endif /* CONFIG_PPP_MULTILINK */
1896
1897 /*
1898  * Channel interface.
1899  */
1900
1901 /*
1902  * Create a new, unattached ppp channel.
1903  */
1904 int
1905 ppp_register_channel(struct ppp_channel *chan)
1906 {
1907         struct channel *pch;
1908
1909         pch = kmalloc(sizeof(struct channel), GFP_KERNEL);
1910         if (pch == 0)
1911                 return -ENOMEM;
1912         memset(pch, 0, sizeof(struct channel));
1913         pch->ppp = NULL;
1914         pch->chan = chan;
1915         chan->ppp = pch;
1916         init_ppp_file(&pch->file, CHANNEL);
1917         pch->file.hdrlen = chan->hdrlen;
1918 #ifdef CONFIG_PPP_MULTILINK
1919         pch->lastseq = -1;
1920 #endif /* CONFIG_PPP_MULTILINK */
1921         init_rwsem(&pch->chan_sem);
1922         spin_lock_init(&pch->downl);
1923         pch->upl = RW_LOCK_UNLOCKED;
1924         spin_lock_bh(&all_channels_lock);
1925         pch->file.index = ++last_channel_index;
1926         list_add(&pch->list, &new_channels);
1927         atomic_inc(&channel_count);
1928         spin_unlock_bh(&all_channels_lock);
1929         return 0;
1930 }
1931
1932 /*
1933  * Return the index of a channel.
1934  */
1935 int ppp_channel_index(struct ppp_channel *chan)
1936 {
1937         struct channel *pch = chan->ppp;
1938
1939         if (pch != 0)
1940                 return pch->file.index;
1941         return -1;
1942 }
1943
1944 /*
1945  * Return the PPP unit number to which a channel is connected.
1946  */
1947 int ppp_unit_number(struct ppp_channel *chan)
1948 {
1949         struct channel *pch = chan->ppp;
1950         int unit = -1;
1951
1952         if (pch != 0) {
1953                 read_lock_bh(&pch->upl);
1954                 if (pch->ppp != 0)
1955                         unit = pch->ppp->file.index;
1956                 read_unlock_bh(&pch->upl);
1957         }
1958         return unit;
1959 }
1960
1961 /*
1962  * Disconnect a channel from the generic layer.
1963  * This must be called in process context.
1964  */
1965 void
1966 ppp_unregister_channel(struct ppp_channel *chan)
1967 {
1968         struct channel *pch = chan->ppp;
1969
1970         if (pch == 0)
1971                 return;         /* should never happen */
1972         chan->ppp = NULL;
1973
1974         /*
1975          * This ensures that we have returned from any calls into the
1976          * the channel's start_xmit or ioctl routine before we proceed.
1977          */
1978         down_write(&pch->chan_sem);
1979         spin_lock_bh(&pch->downl);
1980         pch->chan = NULL;
1981         spin_unlock_bh(&pch->downl);
1982         up_write(&pch->chan_sem);
1983         ppp_disconnect_channel(pch);
1984         spin_lock_bh(&all_channels_lock);
1985         list_del(&pch->list);
1986         spin_unlock_bh(&all_channels_lock);
1987         pch->file.dead = 1;
1988         wake_up_interruptible(&pch->file.rwait);
1989         if (atomic_dec_and_test(&pch->file.refcnt))
1990                 ppp_destroy_channel(pch);
1991 }
1992
1993 /*
1994  * Callback from a channel when it can accept more to transmit.
1995  * This should be called at BH/softirq level, not interrupt level.
1996  */
1997 void
1998 ppp_output_wakeup(struct ppp_channel *chan)
1999 {
2000         struct channel *pch = chan->ppp;
2001
2002         if (pch == 0)
2003                 return;
2004         ppp_channel_push(pch);
2005 }
2006
2007 /*
2008  * Compression control.
2009  */
2010
2011 /* Process the PPPIOCSCOMPRESS ioctl. */
2012 static int
2013 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2014 {
2015         int err;
2016         struct compressor *cp, *ocomp;
2017         struct ppp_option_data data;
2018         void *state, *ostate;
2019         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2020
2021         err = -EFAULT;
2022         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2023             || (data.length <= CCP_MAX_OPTION_LENGTH
2024                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2025                 goto out;
2026         err = -EINVAL;
2027         if (data.length > CCP_MAX_OPTION_LENGTH
2028             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2029                 goto out;
2030
2031         cp = find_compressor(ccp_option[0]);
2032 #ifdef CONFIG_KMOD
2033         if (cp == 0) {
2034                 request_module("ppp-compress-%d", ccp_option[0]);
2035                 cp = find_compressor(ccp_option[0]);
2036         }
2037 #endif /* CONFIG_KMOD */
2038         if (cp == 0)
2039                 goto out;
2040
2041         err = -ENOBUFS;
2042         if (data.transmit) {
2043                 state = cp->comp_alloc(ccp_option, data.length);
2044                 if (state != 0) {
2045                         ppp_xmit_lock(ppp);
2046                         ppp->xstate &= ~SC_COMP_RUN;
2047                         ocomp = ppp->xcomp;
2048                         ostate = ppp->xc_state;
2049                         ppp->xcomp = cp;
2050                         ppp->xc_state = state;
2051                         ppp_xmit_unlock(ppp);
2052                         if (ostate != 0) {
2053                                 ocomp->comp_free(ostate);
2054                                 module_put(ocomp->owner);
2055                         }
2056                         err = 0;
2057                 } else
2058                         module_put(cp->owner);
2059
2060         } else {
2061                 state = cp->decomp_alloc(ccp_option, data.length);
2062                 if (state != 0) {
2063                         ppp_recv_lock(ppp);
2064                         ppp->rstate &= ~SC_DECOMP_RUN;
2065                         ocomp = ppp->rcomp;
2066                         ostate = ppp->rc_state;
2067                         ppp->rcomp = cp;
2068                         ppp->rc_state = state;
2069                         ppp_recv_unlock(ppp);
2070                         if (ostate != 0) {
2071                                 ocomp->decomp_free(ostate);
2072                                 module_put(ocomp->owner);
2073                         }
2074                         err = 0;
2075                 } else
2076                         module_put(cp->owner);
2077         }
2078
2079  out:
2080         return err;
2081 }
2082
2083 /*
2084  * Look at a CCP packet and update our state accordingly.
2085  * We assume the caller has the xmit or recv path locked.
2086  */
2087 static void
2088 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2089 {
2090         unsigned char *dp;
2091         int len;
2092
2093         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2094                 return; /* no header */
2095         dp = skb->data + 2;
2096
2097         switch (CCP_CODE(dp)) {
2098         case CCP_CONFREQ:
2099
2100                 /* A ConfReq starts negotiation of compression
2101                  * in one direction of transmission,
2102                  * and hence brings it down...but which way?
2103                  *
2104                  * Remember:
2105                  * A ConfReq indicates what the sender would like to receive
2106                  */
2107                 if(inbound)
2108                         /* He is proposing what I should send */
2109                         ppp->xstate &= ~SC_COMP_RUN;
2110                 else
2111                         /* I am proposing to what he should send */
2112                         ppp->rstate &= ~SC_DECOMP_RUN;
2113
2114                 break;
2115
2116         case CCP_TERMREQ:
2117         case CCP_TERMACK:
2118                 /*
2119                  * CCP is going down, both directions of transmission
2120                  */
2121                 ppp->rstate &= ~SC_DECOMP_RUN;
2122                 ppp->xstate &= ~SC_COMP_RUN;
2123                 break;
2124
2125         case CCP_CONFACK:
2126                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2127                         break;
2128                 len = CCP_LENGTH(dp);
2129                 if (!pskb_may_pull(skb, len + 2))
2130                         return;         /* too short */
2131                 dp += CCP_HDRLEN;
2132                 len -= CCP_HDRLEN;
2133                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2134                         break;
2135                 if (inbound) {
2136                         /* we will start receiving compressed packets */
2137                         if (ppp->rc_state == 0)
2138                                 break;
2139                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2140                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2141                                 ppp->rstate |= SC_DECOMP_RUN;
2142                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2143                         }
2144                 } else {
2145                         /* we will soon start sending compressed packets */
2146                         if (ppp->xc_state == 0)
2147                                 break;
2148                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2149                                         ppp->file.index, 0, ppp->debug))
2150                                 ppp->xstate |= SC_COMP_RUN;
2151                 }
2152                 break;
2153
2154         case CCP_RESETACK:
2155                 /* reset the [de]compressor */
2156                 if ((ppp->flags & SC_CCP_UP) == 0)
2157                         break;
2158                 if (inbound) {
2159                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2160                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2161                                 ppp->rstate &= ~SC_DC_ERROR;
2162                         }
2163                 } else {
2164                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2165                                 ppp->xcomp->comp_reset(ppp->xc_state);
2166                 }
2167                 break;
2168         }
2169 }
2170
2171 /* Free up compression resources. */
2172 static void
2173 ppp_ccp_closed(struct ppp *ppp)
2174 {
2175         void *xstate, *rstate;
2176         struct compressor *xcomp, *rcomp;
2177
2178         ppp_lock(ppp);
2179         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2180         ppp->xstate = 0;
2181         xcomp = ppp->xcomp;
2182         xstate = ppp->xc_state;
2183         ppp->xc_state = NULL;
2184         ppp->rstate = 0;
2185         rcomp = ppp->rcomp;
2186         rstate = ppp->rc_state;
2187         ppp->rc_state = NULL;
2188         ppp_unlock(ppp);
2189
2190         if (xstate) {
2191                 xcomp->comp_free(xstate);
2192                 module_put(xcomp->owner);
2193         }
2194         if (rstate) {
2195                 rcomp->decomp_free(rstate);
2196                 module_put(rcomp->owner);
2197         }
2198 }
2199
2200 /* List of compressors. */
2201 static LIST_HEAD(compressor_list);
2202 static spinlock_t compressor_list_lock = SPIN_LOCK_UNLOCKED;
2203
2204 struct compressor_entry {
2205         struct list_head list;
2206         struct compressor *comp;
2207 };
2208
2209 static struct compressor_entry *
2210 find_comp_entry(int proto)
2211 {
2212         struct compressor_entry *ce;
2213         struct list_head *list = &compressor_list;
2214
2215         while ((list = list->next) != &compressor_list) {
2216                 ce = list_entry(list, struct compressor_entry, list);
2217                 if (ce->comp->compress_proto == proto)
2218                         return ce;
2219         }
2220         return NULL;
2221 }
2222
2223 /* Register a compressor */
2224 int
2225 ppp_register_compressor(struct compressor *cp)
2226 {
2227         struct compressor_entry *ce;
2228         int ret;
2229         spin_lock(&compressor_list_lock);
2230         ret = -EEXIST;
2231         if (find_comp_entry(cp->compress_proto) != 0)
2232                 goto out;
2233         ret = -ENOMEM;
2234         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2235         if (ce == 0)
2236                 goto out;
2237         ret = 0;
2238         ce->comp = cp;
2239         list_add(&ce->list, &compressor_list);
2240  out:
2241         spin_unlock(&compressor_list_lock);
2242         return ret;
2243 }
2244
2245 /* Unregister a compressor */
2246 void
2247 ppp_unregister_compressor(struct compressor *cp)
2248 {
2249         struct compressor_entry *ce;
2250
2251         spin_lock(&compressor_list_lock);
2252         ce = find_comp_entry(cp->compress_proto);
2253         if (ce != 0 && ce->comp == cp) {
2254                 list_del(&ce->list);
2255                 kfree(ce);
2256         }
2257         spin_unlock(&compressor_list_lock);
2258 }
2259
2260 /* Find a compressor. */
2261 static struct compressor *
2262 find_compressor(int type)
2263 {
2264         struct compressor_entry *ce;
2265         struct compressor *cp = NULL;
2266
2267         spin_lock(&compressor_list_lock);
2268         ce = find_comp_entry(type);
2269         if (ce != 0) {
2270                 cp = ce->comp;
2271                 if (!try_module_get(cp->owner))
2272                         cp = NULL;
2273         }
2274         spin_unlock(&compressor_list_lock);
2275         return cp;
2276 }
2277
2278 /*
2279  * Miscelleneous stuff.
2280  */
2281
2282 static void
2283 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2284 {
2285         struct slcompress *vj = ppp->vj;
2286
2287         memset(st, 0, sizeof(*st));
2288         st->p.ppp_ipackets = ppp->stats.rx_packets;
2289         st->p.ppp_ierrors = ppp->stats.rx_errors;
2290         st->p.ppp_ibytes = ppp->stats.rx_bytes;
2291         st->p.ppp_opackets = ppp->stats.tx_packets;
2292         st->p.ppp_oerrors = ppp->stats.tx_errors;
2293         st->p.ppp_obytes = ppp->stats.tx_bytes;
2294         if (vj == 0)
2295                 return;
2296         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2297         st->vj.vjs_compressed = vj->sls_o_compressed;
2298         st->vj.vjs_searches = vj->sls_o_searches;
2299         st->vj.vjs_misses = vj->sls_o_misses;
2300         st->vj.vjs_errorin = vj->sls_i_error;
2301         st->vj.vjs_tossed = vj->sls_i_tossed;
2302         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2303         st->vj.vjs_compressedin = vj->sls_i_compressed;
2304 }
2305
2306 /*
2307  * Stuff for handling the lists of ppp units and channels
2308  * and for initialization.
2309  */
2310
2311 /*
2312  * Create a new ppp interface unit.  Fails if it can't allocate memory
2313  * or if there is already a unit with the requested number.
2314  * unit == -1 means allocate a new number.
2315  */
2316 static struct ppp *
2317 ppp_create_interface(int unit, int *retp)
2318 {
2319         struct ppp *ppp;
2320         struct net_device *dev = NULL;
2321         int ret = -ENOMEM;
2322         int i;
2323
2324         ppp = kmalloc(sizeof(struct ppp), GFP_KERNEL);
2325         if (!ppp)
2326                 goto out;
2327         dev = alloc_netdev(0, "", ppp_setup);
2328         if (!dev)
2329                 goto out1;
2330         memset(ppp, 0, sizeof(struct ppp));
2331
2332         ppp->mru = PPP_MRU;
2333         init_ppp_file(&ppp->file, INTERFACE);
2334         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2335         for (i = 0; i < NUM_NP; ++i)
2336                 ppp->npmode[i] = NPMODE_PASS;
2337         INIT_LIST_HEAD(&ppp->channels);
2338         spin_lock_init(&ppp->rlock);
2339         spin_lock_init(&ppp->wlock);
2340 #ifdef CONFIG_PPP_MULTILINK
2341         ppp->minseq = -1;
2342         skb_queue_head_init(&ppp->mrq);
2343 #endif /* CONFIG_PPP_MULTILINK */
2344         ppp->dev = dev;
2345         dev->priv = ppp;
2346
2347         dev->hard_start_xmit = ppp_start_xmit;
2348         dev->get_stats = ppp_net_stats;
2349         dev->do_ioctl = ppp_net_ioctl;
2350
2351         ret = -EEXIST;
2352         down(&all_ppp_sem);
2353         if (unit < 0)
2354                 unit = cardmap_find_first_free(all_ppp_units);
2355         else if (cardmap_get(all_ppp_units, unit) != NULL)
2356                 goto out2;      /* unit already exists */
2357
2358         /* Initialize the new ppp unit */
2359         ppp->file.index = unit;
2360         sprintf(dev->name, "ppp%d", unit);
2361
2362         ret = register_netdev(dev);
2363         if (ret != 0) {
2364                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2365                        dev->name, ret);
2366                 goto out2;
2367         }
2368
2369         atomic_inc(&ppp_unit_count);
2370         cardmap_set(&all_ppp_units, unit, ppp);
2371         up(&all_ppp_sem);
2372         *retp = 0;
2373         return ppp;
2374
2375 out2:
2376         up(&all_ppp_sem);
2377         free_netdev(dev);
2378 out1:
2379         kfree(ppp);
2380 out:
2381         *retp = ret;
2382         return NULL;
2383 }
2384
2385 /*
2386  * Initialize a ppp_file structure.
2387  */
2388 static void
2389 init_ppp_file(struct ppp_file *pf, int kind)
2390 {
2391         pf->kind = kind;
2392         skb_queue_head_init(&pf->xq);
2393         skb_queue_head_init(&pf->rq);
2394         atomic_set(&pf->refcnt, 1);
2395         init_waitqueue_head(&pf->rwait);
2396 }
2397
2398 /*
2399  * Take down a ppp interface unit - called when the owning file
2400  * (the one that created the unit) is closed or detached.
2401  */
2402 static void ppp_shutdown_interface(struct ppp *ppp)
2403 {
2404         struct net_device *dev;
2405
2406         down(&all_ppp_sem);
2407         ppp_lock(ppp);
2408         dev = ppp->dev;
2409         ppp->dev = NULL;
2410         ppp_unlock(ppp);
2411         /* This will call dev_close() for us. */
2412         if (dev) {
2413                 unregister_netdev(dev);
2414                 free_netdev(dev);
2415         }
2416         cardmap_set(&all_ppp_units, ppp->file.index, NULL);
2417         ppp->file.dead = 1;
2418         ppp->owner = NULL;
2419         wake_up_interruptible(&ppp->file.rwait);
2420         up(&all_ppp_sem);
2421 }
2422
2423 /*
2424  * Free the memory used by a ppp unit.  This is only called once
2425  * there are no channels connected to the unit and no file structs
2426  * that reference the unit.
2427  */
2428 static void ppp_destroy_interface(struct ppp *ppp)
2429 {
2430         atomic_dec(&ppp_unit_count);
2431
2432         if (!ppp->file.dead || ppp->n_channels) {
2433                 /* "can't happen" */
2434                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2435                        "n_channels=%d !\n", ppp, ppp->file.dead,
2436                        ppp->n_channels);
2437                 return;
2438         }
2439
2440         ppp_ccp_closed(ppp);
2441         if (ppp->vj) {
2442                 slhc_free(ppp->vj);
2443                 ppp->vj = NULL;
2444         }
2445         skb_queue_purge(&ppp->file.xq);
2446         skb_queue_purge(&ppp->file.rq);
2447 #ifdef CONFIG_PPP_MULTILINK
2448         skb_queue_purge(&ppp->mrq);
2449 #endif /* CONFIG_PPP_MULTILINK */
2450 #ifdef CONFIG_PPP_FILTER
2451         if (ppp->pass_filter) {
2452                 kfree(ppp->pass_filter);
2453                 ppp->pass_filter = NULL;
2454         }
2455         if (ppp->active_filter) {
2456                 kfree(ppp->active_filter);
2457                 ppp->active_filter = NULL;
2458         }
2459 #endif /* CONFIG_PPP_FILTER */
2460
2461         kfree(ppp);
2462 }
2463
2464 /*
2465  * Locate an existing ppp unit.
2466  * The caller should have locked the all_ppp_sem.
2467  */
2468 static struct ppp *
2469 ppp_find_unit(int unit)
2470 {
2471         return cardmap_get(all_ppp_units, unit);
2472 }
2473
2474 /*
2475  * Locate an existing ppp channel.
2476  * The caller should have locked the all_channels_lock.
2477  * First we look in the new_channels list, then in the
2478  * all_channels list.  If found in the new_channels list,
2479  * we move it to the all_channels list.  This is for speed
2480  * when we have a lot of channels in use.
2481  */
2482 static struct channel *
2483 ppp_find_channel(int unit)
2484 {
2485         struct channel *pch;
2486         struct list_head *list;
2487
2488         list = &new_channels;
2489         while ((list = list->next) != &new_channels) {
2490                 pch = list_entry(list, struct channel, list);
2491                 if (pch->file.index == unit) {
2492                         list_del(&pch->list);
2493                         list_add(&pch->list, &all_channels);
2494                         return pch;
2495                 }
2496         }
2497         list = &all_channels;
2498         while ((list = list->next) != &all_channels) {
2499                 pch = list_entry(list, struct channel, list);
2500                 if (pch->file.index == unit)
2501                         return pch;
2502         }
2503         return NULL;
2504 }
2505
2506 /*
2507  * Connect a PPP channel to a PPP interface unit.
2508  */
2509 static int
2510 ppp_connect_channel(struct channel *pch, int unit)
2511 {
2512         struct ppp *ppp;
2513         int ret = -ENXIO;
2514         int hdrlen;
2515
2516         down(&all_ppp_sem);
2517         ppp = ppp_find_unit(unit);
2518         if (ppp == 0)
2519                 goto out;
2520         write_lock_bh(&pch->upl);
2521         ret = -EINVAL;
2522         if (pch->ppp != 0)
2523                 goto outl;
2524
2525         ppp_lock(ppp);
2526         if (pch->file.hdrlen > ppp->file.hdrlen)
2527                 ppp->file.hdrlen = pch->file.hdrlen;
2528         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2529         if (ppp->dev && hdrlen > ppp->dev->hard_header_len)
2530                 ppp->dev->hard_header_len = hdrlen;
2531         list_add_tail(&pch->clist, &ppp->channels);
2532         ++ppp->n_channels;
2533         pch->ppp = ppp;
2534         atomic_inc(&ppp->file.refcnt);
2535         ppp_unlock(ppp);
2536         ret = 0;
2537
2538  outl:
2539         write_unlock_bh(&pch->upl);
2540  out:
2541         up(&all_ppp_sem);
2542         return ret;
2543 }
2544
2545 /*
2546  * Disconnect a channel from its ppp unit.
2547  */
2548 static int
2549 ppp_disconnect_channel(struct channel *pch)
2550 {
2551         struct ppp *ppp;
2552         int err = -EINVAL;
2553
2554         write_lock_bh(&pch->upl);
2555         ppp = pch->ppp;
2556         pch->ppp = NULL;
2557         write_unlock_bh(&pch->upl);
2558         if (ppp != 0) {
2559                 /* remove it from the ppp unit's list */
2560                 ppp_lock(ppp);
2561                 list_del(&pch->clist);
2562                 --ppp->n_channels;
2563                 ppp_unlock(ppp);
2564                 if (atomic_dec_and_test(&ppp->file.refcnt))
2565                         ppp_destroy_interface(ppp);
2566                 err = 0;
2567         }
2568         return err;
2569 }
2570
2571 /*
2572  * Free up the resources used by a ppp channel.
2573  */
2574 static void ppp_destroy_channel(struct channel *pch)
2575 {
2576         atomic_dec(&channel_count);
2577
2578         if (!pch->file.dead) {
2579                 /* "can't happen" */
2580                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2581                        pch);
2582                 return;
2583         }
2584         skb_queue_purge(&pch->file.xq);
2585         skb_queue_purge(&pch->file.rq);
2586         kfree(pch);
2587 }
2588
2589 static void __exit ppp_cleanup(void)
2590 {
2591         /* should never happen */
2592         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2593                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2594         cardmap_destroy(&all_ppp_units);
2595         if (unregister_chrdev(PPP_MAJOR, "ppp") != 0)
2596                 printk(KERN_ERR "PPP: failed to unregister PPP device\n");
2597         devfs_remove("ppp");
2598         class_simple_device_remove(MKDEV(PPP_MAJOR, 0));
2599         class_simple_destroy(ppp_class);
2600 }
2601
2602 /*
2603  * Cardmap implementation.
2604  */
2605 static void *cardmap_get(struct cardmap *map, unsigned int nr)
2606 {
2607         struct cardmap *p;
2608         int i;
2609
2610         for (p = map; p != NULL; ) {
2611                 if ((i = nr >> p->shift) >= CARDMAP_WIDTH)
2612                         return NULL;
2613                 if (p->shift == 0)
2614                         return p->ptr[i];
2615                 nr &= ~(CARDMAP_MASK << p->shift);
2616                 p = p->ptr[i];
2617         }
2618         return NULL;
2619 }
2620
2621 static void cardmap_set(struct cardmap **pmap, unsigned int nr, void *ptr)
2622 {
2623         struct cardmap *p;
2624         int i;
2625
2626         p = *pmap;
2627         if (p == NULL || (nr >> p->shift) >= CARDMAP_WIDTH) {
2628                 do {
2629                         /* need a new top level */
2630                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2631                         memset(np, 0, sizeof(*np));
2632                         np->ptr[0] = p;
2633                         if (p != NULL) {
2634                                 np->shift = p->shift + CARDMAP_ORDER;
2635                                 p->parent = np;
2636                         } else
2637                                 np->shift = 0;
2638                         p = np;
2639                 } while ((nr >> p->shift) >= CARDMAP_WIDTH);
2640                 *pmap = p;
2641         }
2642         while (p->shift > 0) {
2643                 i = (nr >> p->shift) & CARDMAP_MASK;
2644                 if (p->ptr[i] == NULL) {
2645                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2646                         memset(np, 0, sizeof(*np));
2647                         np->shift = p->shift - CARDMAP_ORDER;
2648                         np->parent = p;
2649                         p->ptr[i] = np;
2650                 }
2651                 if (ptr == NULL)
2652                         clear_bit(i, &p->inuse);
2653                 p = p->ptr[i];
2654         }
2655         i = nr & CARDMAP_MASK;
2656         p->ptr[i] = ptr;
2657         if (ptr != NULL)
2658                 set_bit(i, &p->inuse);
2659         else
2660                 clear_bit(i, &p->inuse);
2661 }
2662
2663 static unsigned int cardmap_find_first_free(struct cardmap *map)
2664 {
2665         struct cardmap *p;
2666         unsigned int nr = 0;
2667         int i;
2668
2669         if ((p = map) == NULL)
2670                 return 0;
2671         for (;;) {
2672                 i = find_first_zero_bit(&p->inuse, CARDMAP_WIDTH);
2673                 if (i >= CARDMAP_WIDTH) {
2674                         if (p->parent == NULL)
2675                                 return CARDMAP_WIDTH << p->shift;
2676                         p = p->parent;
2677                         i = (nr >> p->shift) & CARDMAP_MASK;
2678                         set_bit(i, &p->inuse);
2679                         continue;
2680                 }
2681                 nr = (nr & (~CARDMAP_MASK << p->shift)) | (i << p->shift);
2682                 if (p->shift == 0 || p->ptr[i] == NULL)
2683                         return nr;
2684                 p = p->ptr[i];
2685         }
2686 }
2687
2688 static void cardmap_destroy(struct cardmap **pmap)
2689 {
2690         struct cardmap *p, *np;
2691         int i;
2692
2693         for (p = *pmap; p != NULL; p = np) {
2694                 if (p->shift != 0) {
2695                         for (i = 0; i < CARDMAP_WIDTH; ++i)
2696                                 if (p->ptr[i] != NULL)
2697                                         break;
2698                         if (i < CARDMAP_WIDTH) {
2699                                 np = p->ptr[i];
2700                                 p->ptr[i] = NULL;
2701                                 continue;
2702                         }
2703                 }
2704                 np = p->parent;
2705                 kfree(p);
2706         }
2707         *pmap = NULL;
2708 }
2709
2710 /* Module/initialization stuff */
2711
2712 module_init(ppp_init);
2713 module_exit(ppp_cleanup);
2714
2715 EXPORT_SYMBOL(ppp_register_channel);
2716 EXPORT_SYMBOL(ppp_unregister_channel);
2717 EXPORT_SYMBOL(ppp_channel_index);
2718 EXPORT_SYMBOL(ppp_unit_number);
2719 EXPORT_SYMBOL(ppp_input);
2720 EXPORT_SYMBOL(ppp_input_error);
2721 EXPORT_SYMBOL(ppp_output_wakeup);
2722 EXPORT_SYMBOL(ppp_register_compressor);
2723 EXPORT_SYMBOL(ppp_unregister_compressor);
2724 EXPORT_SYMBOL(all_ppp_units); /* for debugging */
2725 EXPORT_SYMBOL(all_channels); /* for debugging */
2726 MODULE_LICENSE("GPL");
2727 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2728 MODULE_ALIAS("/dev/ppp");