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 = 0;
 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 = 0;
 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                 {
1030                         u_int16_t *p = (u_int16_t *) skb_push(skb, 2);
1031
1032                         *p = htons(4); /* indicate outbound in DLT_LINUX_SLL */;
1033                 }
1034                 if (ppp->pass_filter
1035                     && sk_run_filter(skb, ppp->pass_filter,
1036                                      ppp->pass_len) == 0) {
1037                         if (ppp->debug & 1)
1038                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1039                         kfree_skb(skb);
1040                         return;
1041                 }
1042                 /* if this packet passes the active filter, record the time */
1043                 if (!(ppp->active_filter
1044                       && sk_run_filter(skb, ppp->active_filter,
1045                                        ppp->active_len) == 0))
1046                         ppp->last_xmit = jiffies;
1047                 skb_pull(skb, 2);
1048 #else
1049                 /* for data packets, record the time */
1050                 ppp->last_xmit = jiffies;
1051 #endif /* CONFIG_PPP_FILTER */
1052         }
1053
1054         ++ppp->stats.tx_packets;
1055         ppp->stats.tx_bytes += skb->len - 2;
1056
1057         switch (proto) {
1058         case PPP_IP:
1059                 if (ppp->vj == 0 || (ppp->flags & SC_COMP_TCP) == 0)
1060                         break;
1061                 /* try to do VJ TCP header compression */
1062                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1063                                     GFP_ATOMIC);
1064                 if (new_skb == 0) {
1065                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1066                         goto drop;
1067                 }
1068                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1069                 cp = skb->data + 2;
1070                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1071                                     new_skb->data + 2, &cp,
1072                                     !(ppp->flags & SC_NO_TCP_CCID));
1073                 if (cp == skb->data + 2) {
1074                         /* didn't compress */
1075                         kfree_skb(new_skb);
1076                 } else {
1077                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1078                                 proto = PPP_VJC_COMP;
1079                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1080                         } else {
1081                                 proto = PPP_VJC_UNCOMP;
1082                                 cp[0] = skb->data[2];
1083                         }
1084                         kfree_skb(skb);
1085                         skb = new_skb;
1086                         cp = skb_put(skb, len + 2);
1087                         cp[0] = 0;
1088                         cp[1] = proto;
1089                 }
1090                 break;
1091
1092         case PPP_CCP:
1093                 /* peek at outbound CCP frames */
1094                 ppp_ccp_peek(ppp, skb, 0);
1095                 break;
1096         }
1097
1098         /* try to do packet compression */
1099         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0
1100             && proto != PPP_LCP && proto != PPP_CCP) {
1101                 new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len,
1102                                     GFP_ATOMIC);
1103                 if (new_skb == 0) {
1104                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1105                         goto drop;
1106                 }
1107                 if (ppp->dev->hard_header_len > PPP_HDRLEN)
1108                         skb_reserve(new_skb,
1109                                     ppp->dev->hard_header_len - PPP_HDRLEN);
1110
1111                 /* compressor still expects A/C bytes in hdr */
1112                 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1113                                            new_skb->data, skb->len + 2,
1114                                            ppp->dev->mtu + PPP_HDRLEN);
1115                 if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1116                         kfree_skb(skb);
1117                         skb = new_skb;
1118                         skb_put(skb, len);
1119                         skb_pull(skb, 2);       /* pull off A/C bytes */
1120                 } else {
1121                         /* didn't compress, or CCP not up yet */
1122                         kfree_skb(new_skb);
1123                 }
1124         }
1125
1126         /*
1127          * If we are waiting for traffic (demand dialling),
1128          * queue it up for pppd to receive.
1129          */
1130         if (ppp->flags & SC_LOOP_TRAFFIC) {
1131                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1132                         goto drop;
1133                 skb_queue_tail(&ppp->file.rq, skb);
1134                 wake_up_interruptible(&ppp->file.rwait);
1135                 return;
1136         }
1137
1138         ppp->xmit_pending = skb;
1139         ppp_push(ppp);
1140         return;
1141
1142  drop:
1143         kfree_skb(skb);
1144         ++ppp->stats.tx_errors;
1145 }
1146
1147 /*
1148  * Try to send the frame in xmit_pending.
1149  * The caller should have the xmit path locked.
1150  */
1151 static void
1152 ppp_push(struct ppp *ppp)
1153 {
1154         struct list_head *list;
1155         struct channel *pch;
1156         struct sk_buff *skb = ppp->xmit_pending;
1157
1158         if (skb == 0)
1159                 return;
1160
1161         list = &ppp->channels;
1162         if (list_empty(list)) {
1163                 /* nowhere to send the packet, just drop it */
1164                 ppp->xmit_pending = 0;
1165                 kfree_skb(skb);
1166                 return;
1167         }
1168
1169         if ((ppp->flags & SC_MULTILINK) == 0) {
1170                 /* not doing multilink: send it down the first channel */
1171                 list = list->next;
1172                 pch = list_entry(list, struct channel, clist);
1173
1174                 spin_lock_bh(&pch->downl);
1175                 if (pch->chan) {
1176                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1177                                 ppp->xmit_pending = 0;
1178                 } else {
1179                         /* channel got unregistered */
1180                         kfree_skb(skb);
1181                         ppp->xmit_pending = 0;
1182                 }
1183                 spin_unlock_bh(&pch->downl);
1184                 return;
1185         }
1186
1187 #ifdef CONFIG_PPP_MULTILINK
1188         /* Multilink: fragment the packet over as many links
1189            as can take the packet at the moment. */
1190         if (!ppp_mp_explode(ppp, skb))
1191                 return;
1192 #endif /* CONFIG_PPP_MULTILINK */
1193
1194         ppp->xmit_pending = 0;
1195         kfree_skb(skb);
1196 }
1197
1198 #ifdef CONFIG_PPP_MULTILINK
1199 /*
1200  * Divide a packet to be transmitted into fragments and
1201  * send them out the individual links.
1202  */
1203 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1204 {
1205         int nch, len, fragsize;
1206         int i, bits, hdrlen, mtu;
1207         int flen, fnb;
1208         unsigned char *p, *q;
1209         struct list_head *list;
1210         struct channel *pch;
1211         struct sk_buff *frag;
1212         struct ppp_channel *chan;
1213
1214         nch = 0;
1215         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1216         list = &ppp->channels;
1217         while ((list = list->next) != &ppp->channels) {
1218                 pch = list_entry(list, struct channel, clist);
1219                 nch += pch->avail = (skb_queue_len(&pch->file.xq) == 0);
1220                 /*
1221                  * If a channel hasn't had a fragment yet, it has to get
1222                  * one before we send any fragments on later channels.
1223                  * If it can't take a fragment now, don't give any
1224                  * to subsequent channels.
1225                  */
1226                 if (!pch->had_frag && !pch->avail) {
1227                         while ((list = list->next) != &ppp->channels) {
1228                                 pch = list_entry(list, struct channel, clist);
1229                                 pch->avail = 0;
1230                         }
1231                         break;
1232                 }
1233         }
1234         if (nch == 0)
1235                 return 0;       /* can't take now, leave it in xmit_pending */
1236
1237         /* Do protocol field compression (XXX this should be optional) */
1238         p = skb->data;
1239         len = skb->len;
1240         if (*p == 0) {
1241                 ++p;
1242                 --len;
1243         }
1244
1245         /* decide on fragment size */
1246         fragsize = len;
1247         if (nch > 1) {
1248                 int maxch = ROUNDUP(len, MIN_FRAG_SIZE);
1249                 if (nch > maxch)
1250                         nch = maxch;
1251                 fragsize = ROUNDUP(fragsize, nch);
1252         }
1253
1254         /* skip to the channel after the one we last used
1255            and start at that one */
1256         for (i = 0; i < ppp->nxchan; ++i) {
1257                 list = list->next;
1258                 if (list == &ppp->channels) {
1259                         i = 0;
1260                         break;
1261                 }
1262         }
1263
1264         /* create a fragment for each channel */
1265         bits = B;
1266         do {
1267                 list = list->next;
1268                 if (list == &ppp->channels) {
1269                         i = 0;
1270                         continue;
1271                 }
1272                 pch = list_entry(list, struct channel, clist);
1273                 ++i;
1274                 if (!pch->avail)
1275                         continue;
1276
1277                 /* check the channel's mtu and whether it is still attached. */
1278                 spin_lock_bh(&pch->downl);
1279                 if (pch->chan == 0 || (mtu = pch->chan->mtu) < hdrlen) {
1280                         /* can't use this channel */
1281                         spin_unlock_bh(&pch->downl);
1282                         pch->avail = 0;
1283                         if (--nch == 0)
1284                                 break;
1285                         continue;
1286                 }
1287
1288                 /*
1289                  * We have to create multiple fragments for this channel
1290                  * if fragsize is greater than the channel's mtu.
1291                  */
1292                 if (fragsize > len)
1293                         fragsize = len;
1294                 for (flen = fragsize; flen > 0; flen -= fnb) {
1295                         fnb = flen;
1296                         if (fnb > mtu + 2 - hdrlen)
1297                                 fnb = mtu + 2 - hdrlen;
1298                         if (fnb >= len)
1299                                 bits |= E;
1300                         frag = alloc_skb(fnb + hdrlen, GFP_ATOMIC);
1301                         if (frag == 0)
1302                                 goto noskb;
1303                         q = skb_put(frag, fnb + hdrlen);
1304                         /* make the MP header */
1305                         q[0] = PPP_MP >> 8;
1306                         q[1] = PPP_MP;
1307                         if (ppp->flags & SC_MP_XSHORTSEQ) {
1308                                 q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1309                                 q[3] = ppp->nxseq;
1310                         } else {
1311                                 q[2] = bits;
1312                                 q[3] = ppp->nxseq >> 16;
1313                                 q[4] = ppp->nxseq >> 8;
1314                                 q[5] = ppp->nxseq;
1315                         }
1316
1317                         /* copy the data in */
1318                         memcpy(q + hdrlen, p, fnb);
1319
1320                         /* try to send it down the channel */
1321                         chan = pch->chan;
1322                         if (!chan->ops->start_xmit(chan, frag))
1323                                 skb_queue_tail(&pch->file.xq, frag);
1324                         pch->had_frag = 1;
1325                         p += fnb;
1326                         len -= fnb;
1327                         ++ppp->nxseq;
1328                         bits = 0;
1329                 }
1330                 spin_unlock_bh(&pch->downl);
1331         } while (len > 0);
1332         ppp->nxchan = i;
1333
1334         return 1;
1335
1336  noskb:
1337         spin_unlock_bh(&pch->downl);
1338         if (ppp->debug & 1)
1339                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1340         ++ppp->stats.tx_errors;
1341         ++ppp->nxseq;
1342         return 1;       /* abandon the frame */
1343 }
1344 #endif /* CONFIG_PPP_MULTILINK */
1345
1346 /*
1347  * Try to send data out on a channel.
1348  */
1349 static void
1350 ppp_channel_push(struct channel *pch)
1351 {
1352         struct sk_buff *skb;
1353         struct ppp *ppp;
1354
1355         spin_lock_bh(&pch->downl);
1356         if (pch->chan != 0) {
1357                 while (skb_queue_len(&pch->file.xq) > 0) {
1358                         skb = skb_dequeue(&pch->file.xq);
1359                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1360                                 /* put the packet back and try again later */
1361                                 skb_queue_head(&pch->file.xq, skb);
1362                                 break;
1363                         }
1364                 }
1365         } else {
1366                 /* channel got deregistered */
1367                 skb_queue_purge(&pch->file.xq);
1368         }
1369         spin_unlock_bh(&pch->downl);
1370         /* see if there is anything from the attached unit to be sent */
1371         if (skb_queue_len(&pch->file.xq) == 0) {
1372                 read_lock_bh(&pch->upl);
1373                 ppp = pch->ppp;
1374                 if (ppp != 0)
1375                         ppp_xmit_process(ppp);
1376                 read_unlock_bh(&pch->upl);
1377         }
1378 }
1379
1380 /*
1381  * Receive-side routines.
1382  */
1383
1384 /* misuse a few fields of the skb for MP reconstruction */
1385 #define sequence        priority
1386 #define BEbits          cb[0]
1387
1388 static inline void
1389 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1390 {
1391         ppp_recv_lock(ppp);
1392         /* ppp->dev == 0 means interface is closing down */
1393         if (ppp->dev != 0)
1394                 ppp_receive_frame(ppp, skb, pch);
1395         else
1396                 kfree_skb(skb);
1397         ppp_recv_unlock(ppp);
1398 }
1399
1400 void
1401 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1402 {
1403         struct channel *pch = chan->ppp;
1404         int proto;
1405
1406         if (pch == 0 || skb->len == 0) {
1407                 kfree_skb(skb);
1408                 return;
1409         }
1410
1411         proto = PPP_PROTO(skb);
1412         read_lock_bh(&pch->upl);
1413         if (pch->ppp == 0 || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1414                 /* put it on the channel queue */
1415                 skb_queue_tail(&pch->file.rq, skb);
1416                 /* drop old frames if queue too long */
1417                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1418                        && (skb = skb_dequeue(&pch->file.rq)) != 0)
1419                         kfree_skb(skb);
1420                 wake_up_interruptible(&pch->file.rwait);
1421         } else {
1422                 ppp_do_recv(pch->ppp, skb, pch);
1423         }
1424         read_unlock_bh(&pch->upl);
1425 }
1426
1427 /* Put a 0-length skb in the receive queue as an error indication */
1428 void
1429 ppp_input_error(struct ppp_channel *chan, int code)
1430 {
1431         struct channel *pch = chan->ppp;
1432         struct sk_buff *skb;
1433
1434         if (pch == 0)
1435                 return;
1436
1437         read_lock_bh(&pch->upl);
1438         if (pch->ppp != 0) {
1439                 skb = alloc_skb(0, GFP_ATOMIC);
1440                 if (skb != 0) {
1441                         skb->len = 0;           /* probably unnecessary */
1442                         skb->cb[0] = code;
1443                         ppp_do_recv(pch->ppp, skb, pch);
1444                 }
1445         }
1446         read_unlock_bh(&pch->upl);
1447 }
1448
1449 /*
1450  * We come in here to process a received frame.
1451  * The receive side of the ppp unit is locked.
1452  */
1453 static void
1454 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1455 {
1456         if (skb->len >= 2) {
1457 #ifdef CONFIG_PPP_MULTILINK
1458                 /* XXX do channel-level decompression here */
1459                 if (PPP_PROTO(skb) == PPP_MP)
1460                         ppp_receive_mp_frame(ppp, skb, pch);
1461                 else
1462 #endif /* CONFIG_PPP_MULTILINK */
1463                         ppp_receive_nonmp_frame(ppp, skb);
1464                 return;
1465         }
1466
1467         if (skb->len > 0)
1468                 /* note: a 0-length skb is used as an error indication */
1469                 ++ppp->stats.rx_length_errors;
1470
1471         kfree_skb(skb);
1472         ppp_receive_error(ppp);
1473 }
1474
1475 static void
1476 ppp_receive_error(struct ppp *ppp)
1477 {
1478         ++ppp->stats.rx_errors;
1479         if (ppp->vj != 0)
1480                 slhc_toss(ppp->vj);
1481 }
1482
1483 static void
1484 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1485 {
1486         struct sk_buff *ns;
1487         int proto, len, npi;
1488
1489         /*
1490          * Decompress the frame, if compressed.
1491          * Note that some decompressors need to see uncompressed frames
1492          * that come in as well as compressed frames.
1493          */
1494         if (ppp->rc_state != 0 && (ppp->rstate & SC_DECOMP_RUN)
1495             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1496                 skb = ppp_decompress_frame(ppp, skb);
1497
1498         proto = PPP_PROTO(skb);
1499         switch (proto) {
1500         case PPP_VJC_COMP:
1501                 /* decompress VJ compressed packets */
1502                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1503                         goto err;
1504
1505                 if (skb_tailroom(skb) < 124) {
1506                         /* copy to a new sk_buff with more tailroom */
1507                         ns = dev_alloc_skb(skb->len + 128);
1508                         if (ns == 0) {
1509                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1510                                 goto err;
1511                         }
1512                         skb_reserve(ns, 2);
1513                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1514                         kfree_skb(skb);
1515                         skb = ns;
1516                 }
1517                 else if (!pskb_may_pull(skb, skb->len))
1518                         goto err;
1519
1520                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1521                 if (len <= 0) {
1522                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1523                         goto err;
1524                 }
1525                 len += 2;
1526                 if (len > skb->len)
1527                         skb_put(skb, len - skb->len);
1528                 else if (len < skb->len)
1529                         skb_trim(skb, len);
1530                 proto = PPP_IP;
1531                 break;
1532
1533         case PPP_VJC_UNCOMP:
1534                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1535                         goto err;
1536
1537                 /* Until we fix the decompressor need to make sure
1538                  * data portion is linear.
1539                  */
1540                 if (!pskb_may_pull(skb, skb->len))
1541                         goto err;
1542
1543                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1544                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1545                         goto err;
1546                 }
1547                 proto = PPP_IP;
1548                 break;
1549
1550         case PPP_CCP:
1551                 ppp_ccp_peek(ppp, skb, 1);
1552                 break;
1553         }
1554
1555         ++ppp->stats.rx_packets;
1556         ppp->stats.rx_bytes += skb->len - 2;
1557
1558         npi = proto_to_npindex(proto);
1559         if (npi < 0) {
1560                 /* control or unknown frame - pass it to pppd */
1561                 skb_queue_tail(&ppp->file.rq, skb);
1562                 /* limit queue length by dropping old frames */
1563                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1564                        && (skb = skb_dequeue(&ppp->file.rq)) != 0)
1565                         kfree_skb(skb);
1566                 /* wake up any process polling or blocking on read */
1567                 wake_up_interruptible(&ppp->file.rwait);
1568
1569         } else {
1570                 /* network protocol frame - give it to the kernel */
1571
1572 #ifdef CONFIG_PPP_FILTER
1573                 /* check if the packet passes the pass and active filters */
1574                 /* the filter instructions are constructed assuming
1575                    a four-byte PPP header on each packet */
1576                 {
1577                         u_int16_t *p = (u_int16_t *) skb_push(skb, 2);
1578
1579                         *p = 0; /* indicate inbound in DLT_LINUX_SLL */
1580                 }
1581                 if (ppp->pass_filter
1582                     && sk_run_filter(skb, ppp->pass_filter,
1583                                      ppp->pass_len) == 0) {
1584                         if (ppp->debug & 1)
1585                                 printk(KERN_DEBUG "PPP: inbound frame not passed\n");
1586                         kfree_skb(skb);
1587                         return;
1588                 }
1589                 if (!(ppp->active_filter
1590                       && sk_run_filter(skb, ppp->active_filter,
1591                                        ppp->active_len) == 0))
1592                         ppp->last_recv = jiffies;
1593                 skb_pull(skb, 2);
1594 #else
1595                 ppp->last_recv = jiffies;
1596 #endif /* CONFIG_PPP_FILTER */
1597
1598                 if ((ppp->dev->flags & IFF_UP) == 0
1599                     || ppp->npmode[npi] != NPMODE_PASS) {
1600                         kfree_skb(skb);
1601                 } else {
1602                         skb_pull(skb, 2);       /* chop off protocol */
1603                         skb->dev = ppp->dev;
1604                         skb->protocol = htons(npindex_to_ethertype[npi]);
1605                         skb->mac.raw = skb->data;
1606                         netif_rx(skb);
1607                         ppp->dev->last_rx = jiffies;
1608                 }
1609         }
1610         return;
1611
1612  err:
1613         kfree_skb(skb);
1614         ppp_receive_error(ppp);
1615 }
1616
1617 static struct sk_buff *
1618 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1619 {
1620         int proto = PPP_PROTO(skb);
1621         struct sk_buff *ns;
1622         int len;
1623
1624         /* Until we fix all the decompressor's need to make sure
1625          * data portion is linear.
1626          */
1627         if (!pskb_may_pull(skb, skb->len))
1628                 goto err;
1629
1630         if (proto == PPP_COMP) {
1631                 ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN);
1632                 if (ns == 0) {
1633                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1634                         goto err;
1635                 }
1636                 /* the decompressor still expects the A/C bytes in the hdr */
1637                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1638                                 skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN);
1639                 if (len < 0) {
1640                         /* Pass the compressed frame to pppd as an
1641                            error indication. */
1642                         if (len == DECOMP_FATALERROR)
1643                                 ppp->rstate |= SC_DC_FERROR;
1644                         kfree_skb(ns);
1645                         goto err;
1646                 }
1647
1648                 kfree_skb(skb);
1649                 skb = ns;
1650                 skb_put(skb, len);
1651                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1652
1653         } else {
1654                 /* Uncompressed frame - pass to decompressor so it
1655                    can update its dictionary if necessary. */
1656                 if (ppp->rcomp->incomp)
1657                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1658                                            skb->len + 2);
1659         }
1660
1661         return skb;
1662
1663  err:
1664         ppp->rstate |= SC_DC_ERROR;
1665         ppp_receive_error(ppp);
1666         return skb;
1667 }
1668
1669 #ifdef CONFIG_PPP_MULTILINK
1670 /*
1671  * Receive a multilink frame.
1672  * We put it on the reconstruction queue and then pull off
1673  * as many completed frames as we can.
1674  */
1675 static void
1676 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1677 {
1678         u32 mask, seq;
1679         struct list_head *l;
1680         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1681
1682         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1683                 goto err;               /* no good, throw it away */
1684
1685         /* Decode sequence number and begin/end bits */
1686         if (ppp->flags & SC_MP_SHORTSEQ) {
1687                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1688                 mask = 0xfff;
1689         } else {
1690                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1691                 mask = 0xffffff;
1692         }
1693         skb->BEbits = skb->data[2];
1694         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1695
1696         /*
1697          * Do protocol ID decompression on the first fragment of each packet.
1698          */
1699         if ((skb->BEbits & B) && (skb->data[0] & 1))
1700                 *skb_push(skb, 1) = 0;
1701
1702         /*
1703          * Expand sequence number to 32 bits, making it as close
1704          * as possible to ppp->minseq.
1705          */
1706         seq |= ppp->minseq & ~mask;
1707         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1708                 seq += mask + 1;
1709         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1710                 seq -= mask + 1;        /* should never happen */
1711         skb->sequence = seq;
1712         pch->lastseq = seq;
1713
1714         /*
1715          * If this packet comes before the next one we were expecting,
1716          * drop it.
1717          */
1718         if (seq_before(seq, ppp->nextseq)) {
1719                 kfree_skb(skb);
1720                 ++ppp->stats.rx_dropped;
1721                 ppp_receive_error(ppp);
1722                 return;
1723         }
1724
1725         /*
1726          * Reevaluate minseq, the minimum over all channels of the
1727          * last sequence number received on each channel.  Because of
1728          * the increasing sequence number rule, we know that any fragment
1729          * before `minseq' which hasn't arrived is never going to arrive.
1730          * The list of channels can't change because we have the receive
1731          * side of the ppp unit locked.
1732          */
1733         for (l = ppp->channels.next; l != &ppp->channels; l = l->next) {
1734                 struct channel *ch = list_entry(l, struct channel, clist);
1735                 if (seq_before(ch->lastseq, seq))
1736                         seq = ch->lastseq;
1737         }
1738         if (seq_before(ppp->minseq, seq))
1739                 ppp->minseq = seq;
1740
1741         /* Put the fragment on the reconstruction queue */
1742         ppp_mp_insert(ppp, skb);
1743
1744         /* If the queue is getting long, don't wait any longer for packets
1745            before the start of the queue. */
1746         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN
1747             && seq_before(ppp->minseq, ppp->mrq.next->sequence))
1748                 ppp->minseq = ppp->mrq.next->sequence;
1749
1750         /* Pull completed packets off the queue and receive them. */
1751         while ((skb = ppp_mp_reconstruct(ppp)) != 0)
1752                 ppp_receive_nonmp_frame(ppp, skb);
1753
1754         return;
1755
1756  err:
1757         kfree_skb(skb);
1758         ppp_receive_error(ppp);
1759 }
1760
1761 /*
1762  * Insert a fragment on the MP reconstruction queue.
1763  * The queue is ordered by increasing sequence number.
1764  */
1765 static void
1766 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1767 {
1768         struct sk_buff *p;
1769         struct sk_buff_head *list = &ppp->mrq;
1770         u32 seq = skb->sequence;
1771
1772         /* N.B. we don't need to lock the list lock because we have the
1773            ppp unit receive-side lock. */
1774         for (p = list->next; p != (struct sk_buff *)list; p = p->next)
1775                 if (seq_before(seq, p->sequence))
1776                         break;
1777         __skb_insert(skb, p->prev, p, list);
1778 }
1779
1780 /*
1781  * Reconstruct a packet from the MP fragment queue.
1782  * We go through increasing sequence numbers until we find a
1783  * complete packet, or we get to the sequence number for a fragment
1784  * which hasn't arrived but might still do so.
1785  */
1786 struct sk_buff *
1787 ppp_mp_reconstruct(struct ppp *ppp)
1788 {
1789         u32 seq = ppp->nextseq;
1790         u32 minseq = ppp->minseq;
1791         struct sk_buff_head *list = &ppp->mrq;
1792         struct sk_buff *p, *next;
1793         struct sk_buff *head, *tail;
1794         struct sk_buff *skb = NULL;
1795         int lost = 0, len = 0;
1796
1797         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1798                 return NULL;
1799         head = list->next;
1800         tail = NULL;
1801         for (p = head; p != (struct sk_buff *) list; p = next) {
1802                 next = p->next;
1803                 if (seq_before(p->sequence, seq)) {
1804                         /* this can't happen, anyway ignore the skb */
1805                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1806                                p->sequence, seq);
1807                         head = next;
1808                         continue;
1809                 }
1810                 if (p->sequence != seq) {
1811                         /* Fragment `seq' is missing.  If it is after
1812                            minseq, it might arrive later, so stop here. */
1813                         if (seq_after(seq, minseq))
1814                                 break;
1815                         /* Fragment `seq' is lost, keep going. */
1816                         lost = 1;
1817                         seq = seq_before(minseq, p->sequence)?
1818                                 minseq + 1: p->sequence;
1819                         next = p;
1820                         continue;
1821                 }
1822
1823                 /*
1824                  * At this point we know that all the fragments from
1825                  * ppp->nextseq to seq are either present or lost.
1826                  * Also, there are no complete packets in the queue
1827                  * that have no missing fragments and end before this
1828                  * fragment.
1829                  */
1830
1831                 /* B bit set indicates this fragment starts a packet */
1832                 if (p->BEbits & B) {
1833                         head = p;
1834                         lost = 0;
1835                         len = 0;
1836                 }
1837
1838                 len += p->len;
1839
1840                 /* Got a complete packet yet? */
1841                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
1842                         if (len > ppp->mrru + 2) {
1843                                 ++ppp->stats.rx_length_errors;
1844                                 printk(KERN_DEBUG "PPP: reconstructed packet"
1845                                        " is too long (%d)\n", len);
1846                         } else if (p == head) {
1847                                 /* fragment is complete packet - reuse skb */
1848                                 tail = p;
1849                                 skb = skb_get(p);
1850                                 break;
1851                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
1852                                 ++ppp->stats.rx_missed_errors;
1853                                 printk(KERN_DEBUG "PPP: no memory for "
1854                                        "reconstructed packet");
1855                         } else {
1856                                 tail = p;
1857                                 break;
1858                         }
1859                         ppp->nextseq = seq + 1;
1860                 }
1861
1862                 /*
1863                  * If this is the ending fragment of a packet,
1864                  * and we haven't found a complete valid packet yet,
1865                  * we can discard up to and including this fragment.
1866                  */
1867                 if (p->BEbits & E)
1868                         head = next;
1869
1870                 ++seq;
1871         }
1872
1873         /* If we have a complete packet, copy it all into one skb. */
1874         if (tail != NULL) {
1875                 /* If we have discarded any fragments,
1876                    signal a receive error. */
1877                 if (head->sequence != ppp->nextseq) {
1878                         if (ppp->debug & 1)
1879                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
1880                                        ppp->nextseq, head->sequence-1);
1881                         ++ppp->stats.rx_dropped;
1882                         ppp_receive_error(ppp);
1883                 }
1884
1885                 if (head != tail)
1886                         /* copy to a single skb */
1887                         for (p = head; p != tail->next; p = p->next)
1888                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
1889                 ppp->nextseq = tail->sequence + 1;
1890                 head = tail->next;
1891         }
1892
1893         /* Discard all the skbuffs that we have copied the data out of
1894            or that we can't use. */
1895         while ((p = list->next) != head) {
1896                 __skb_unlink(p, list);
1897                 kfree_skb(p);
1898         }
1899
1900         return skb;
1901 }
1902 #endif /* CONFIG_PPP_MULTILINK */
1903
1904 /*
1905  * Channel interface.
1906  */
1907
1908 /*
1909  * Create a new, unattached ppp channel.
1910  */
1911 int
1912 ppp_register_channel(struct ppp_channel *chan)
1913 {
1914         struct channel *pch;
1915
1916         pch = kmalloc(sizeof(struct channel), GFP_KERNEL);
1917         if (pch == 0)
1918                 return -ENOMEM;
1919         memset(pch, 0, sizeof(struct channel));
1920         pch->ppp = NULL;
1921         pch->chan = chan;
1922         chan->ppp = pch;
1923         init_ppp_file(&pch->file, CHANNEL);
1924         pch->file.hdrlen = chan->hdrlen;
1925 #ifdef CONFIG_PPP_MULTILINK
1926         pch->lastseq = -1;
1927 #endif /* CONFIG_PPP_MULTILINK */
1928         init_rwsem(&pch->chan_sem);
1929         spin_lock_init(&pch->downl);
1930         pch->upl = RW_LOCK_UNLOCKED;
1931         spin_lock_bh(&all_channels_lock);
1932         pch->file.index = ++last_channel_index;
1933         list_add(&pch->list, &new_channels);
1934         atomic_inc(&channel_count);
1935         spin_unlock_bh(&all_channels_lock);
1936         return 0;
1937 }
1938
1939 /*
1940  * Return the index of a channel.
1941  */
1942 int ppp_channel_index(struct ppp_channel *chan)
1943 {
1944         struct channel *pch = chan->ppp;
1945
1946         if (pch != 0)
1947                 return pch->file.index;
1948         return -1;
1949 }
1950
1951 /*
1952  * Return the PPP unit number to which a channel is connected.
1953  */
1954 int ppp_unit_number(struct ppp_channel *chan)
1955 {
1956         struct channel *pch = chan->ppp;
1957         int unit = -1;
1958
1959         if (pch != 0) {
1960                 read_lock_bh(&pch->upl);
1961                 if (pch->ppp != 0)
1962                         unit = pch->ppp->file.index;
1963                 read_unlock_bh(&pch->upl);
1964         }
1965         return unit;
1966 }
1967
1968 /*
1969  * Disconnect a channel from the generic layer.
1970  * This must be called in process context.
1971  */
1972 void
1973 ppp_unregister_channel(struct ppp_channel *chan)
1974 {
1975         struct channel *pch = chan->ppp;
1976
1977         if (pch == 0)
1978                 return;         /* should never happen */
1979         chan->ppp = 0;
1980
1981         /*
1982          * This ensures that we have returned from any calls into the
1983          * the channel's start_xmit or ioctl routine before we proceed.
1984          */
1985         down_write(&pch->chan_sem);
1986         spin_lock_bh(&pch->downl);
1987         pch->chan = 0;
1988         spin_unlock_bh(&pch->downl);
1989         up_write(&pch->chan_sem);
1990         ppp_disconnect_channel(pch);
1991         spin_lock_bh(&all_channels_lock);
1992         list_del(&pch->list);
1993         spin_unlock_bh(&all_channels_lock);
1994         pch->file.dead = 1;
1995         wake_up_interruptible(&pch->file.rwait);
1996         if (atomic_dec_and_test(&pch->file.refcnt))
1997                 ppp_destroy_channel(pch);
1998 }
1999
2000 /*
2001  * Callback from a channel when it can accept more to transmit.
2002  * This should be called at BH/softirq level, not interrupt level.
2003  */
2004 void
2005 ppp_output_wakeup(struct ppp_channel *chan)
2006 {
2007         struct channel *pch = chan->ppp;
2008
2009         if (pch == 0)
2010                 return;
2011         ppp_channel_push(pch);
2012 }
2013
2014 /*
2015  * Compression control.
2016  */
2017
2018 /* Process the PPPIOCSCOMPRESS ioctl. */
2019 static int
2020 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2021 {
2022         int err;
2023         struct compressor *cp, *ocomp;
2024         struct ppp_option_data data;
2025         void *state, *ostate;
2026         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2027
2028         err = -EFAULT;
2029         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2030             || (data.length <= CCP_MAX_OPTION_LENGTH
2031                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2032                 goto out;
2033         err = -EINVAL;
2034         if (data.length > CCP_MAX_OPTION_LENGTH
2035             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2036                 goto out;
2037
2038         cp = find_compressor(ccp_option[0]);
2039 #ifdef CONFIG_KMOD
2040         if (cp == 0) {
2041                 request_module("ppp-compress-%d", ccp_option[0]);
2042                 cp = find_compressor(ccp_option[0]);
2043         }
2044 #endif /* CONFIG_KMOD */
2045         if (cp == 0)
2046                 goto out;
2047
2048         err = -ENOBUFS;
2049         if (data.transmit) {
2050                 state = cp->comp_alloc(ccp_option, data.length);
2051                 if (state != 0) {
2052                         ppp_xmit_lock(ppp);
2053                         ppp->xstate &= ~SC_COMP_RUN;
2054                         ocomp = ppp->xcomp;
2055                         ostate = ppp->xc_state;
2056                         ppp->xcomp = cp;
2057                         ppp->xc_state = state;
2058                         ppp_xmit_unlock(ppp);
2059                         if (ostate != 0) {
2060                                 ocomp->comp_free(ostate);
2061                                 module_put(ocomp->owner);
2062                         }
2063                         err = 0;
2064                 } else
2065                         module_put(cp->owner);
2066
2067         } else {
2068                 state = cp->decomp_alloc(ccp_option, data.length);
2069                 if (state != 0) {
2070                         ppp_recv_lock(ppp);
2071                         ppp->rstate &= ~SC_DECOMP_RUN;
2072                         ocomp = ppp->rcomp;
2073                         ostate = ppp->rc_state;
2074                         ppp->rcomp = cp;
2075                         ppp->rc_state = state;
2076                         ppp_recv_unlock(ppp);
2077                         if (ostate != 0) {
2078                                 ocomp->decomp_free(ostate);
2079                                 module_put(ocomp->owner);
2080                         }
2081                         err = 0;
2082                 } else
2083                         module_put(cp->owner);
2084         }
2085
2086  out:
2087         return err;
2088 }
2089
2090 /*
2091  * Look at a CCP packet and update our state accordingly.
2092  * We assume the caller has the xmit or recv path locked.
2093  */
2094 static void
2095 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2096 {
2097         unsigned char *dp;
2098         int len;
2099
2100         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2101                 return; /* no header */
2102         dp = skb->data + 2;
2103
2104         switch (CCP_CODE(dp)) {
2105         case CCP_CONFREQ:
2106
2107                 /* A ConfReq starts negotiation of compression
2108                  * in one direction of transmission,
2109                  * and hence brings it down...but which way?
2110                  *
2111                  * Remember:
2112                  * A ConfReq indicates what the sender would like to receive
2113                  */
2114                 if(inbound)
2115                         /* He is proposing what I should send */
2116                         ppp->xstate &= ~SC_COMP_RUN;
2117                 else
2118                         /* I am proposing to what he should send */
2119                         ppp->rstate &= ~SC_DECOMP_RUN;
2120
2121                 break;
2122
2123         case CCP_TERMREQ:
2124         case CCP_TERMACK:
2125                 /*
2126                  * CCP is going down, both directions of transmission
2127                  */
2128                 ppp->rstate &= ~SC_DECOMP_RUN;
2129                 ppp->xstate &= ~SC_COMP_RUN;
2130                 break;
2131
2132         case CCP_CONFACK:
2133                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2134                         break;
2135                 len = CCP_LENGTH(dp);
2136                 if (!pskb_may_pull(skb, len + 2))
2137                         return;         /* too short */
2138                 dp += CCP_HDRLEN;
2139                 len -= CCP_HDRLEN;
2140                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2141                         break;
2142                 if (inbound) {
2143                         /* we will start receiving compressed packets */
2144                         if (ppp->rc_state == 0)
2145                                 break;
2146                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2147                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2148                                 ppp->rstate |= SC_DECOMP_RUN;
2149                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2150                         }
2151                 } else {
2152                         /* we will soon start sending compressed packets */
2153                         if (ppp->xc_state == 0)
2154                                 break;
2155                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2156                                         ppp->file.index, 0, ppp->debug))
2157                                 ppp->xstate |= SC_COMP_RUN;
2158                 }
2159                 break;
2160
2161         case CCP_RESETACK:
2162                 /* reset the [de]compressor */
2163                 if ((ppp->flags & SC_CCP_UP) == 0)
2164                         break;
2165                 if (inbound) {
2166                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2167                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2168                                 ppp->rstate &= ~SC_DC_ERROR;
2169                         }
2170                 } else {
2171                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2172                                 ppp->xcomp->comp_reset(ppp->xc_state);
2173                 }
2174                 break;
2175         }
2176 }
2177
2178 /* Free up compression resources. */
2179 static void
2180 ppp_ccp_closed(struct ppp *ppp)
2181 {
2182         void *xstate, *rstate;
2183         struct compressor *xcomp, *rcomp;
2184
2185         ppp_lock(ppp);
2186         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2187         ppp->xstate = 0;
2188         xcomp = ppp->xcomp;
2189         xstate = ppp->xc_state;
2190         ppp->xc_state = 0;
2191         ppp->rstate = 0;
2192         rcomp = ppp->rcomp;
2193         rstate = ppp->rc_state;
2194         ppp->rc_state = 0;
2195         ppp_unlock(ppp);
2196
2197         if (xstate) {
2198                 xcomp->comp_free(xstate);
2199                 module_put(xcomp->owner);
2200         }
2201         if (rstate) {
2202                 rcomp->decomp_free(rstate);
2203                 module_put(rcomp->owner);
2204         }
2205 }
2206
2207 /* List of compressors. */
2208 static LIST_HEAD(compressor_list);
2209 static spinlock_t compressor_list_lock = SPIN_LOCK_UNLOCKED;
2210
2211 struct compressor_entry {
2212         struct list_head list;
2213         struct compressor *comp;
2214 };
2215
2216 static struct compressor_entry *
2217 find_comp_entry(int proto)
2218 {
2219         struct compressor_entry *ce;
2220         struct list_head *list = &compressor_list;
2221
2222         while ((list = list->next) != &compressor_list) {
2223                 ce = list_entry(list, struct compressor_entry, list);
2224                 if (ce->comp->compress_proto == proto)
2225                         return ce;
2226         }
2227         return 0;
2228 }
2229
2230 /* Register a compressor */
2231 int
2232 ppp_register_compressor(struct compressor *cp)
2233 {
2234         struct compressor_entry *ce;
2235         int ret;
2236         spin_lock(&compressor_list_lock);
2237         ret = -EEXIST;
2238         if (find_comp_entry(cp->compress_proto) != 0)
2239                 goto out;
2240         ret = -ENOMEM;
2241         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2242         if (ce == 0)
2243                 goto out;
2244         ret = 0;
2245         ce->comp = cp;
2246         list_add(&ce->list, &compressor_list);
2247  out:
2248         spin_unlock(&compressor_list_lock);
2249         return ret;
2250 }
2251
2252 /* Unregister a compressor */
2253 void
2254 ppp_unregister_compressor(struct compressor *cp)
2255 {
2256         struct compressor_entry *ce;
2257
2258         spin_lock(&compressor_list_lock);
2259         ce = find_comp_entry(cp->compress_proto);
2260         if (ce != 0 && ce->comp == cp) {
2261                 list_del(&ce->list);
2262                 kfree(ce);
2263         }
2264         spin_unlock(&compressor_list_lock);
2265 }
2266
2267 /* Find a compressor. */
2268 static struct compressor *
2269 find_compressor(int type)
2270 {
2271         struct compressor_entry *ce;
2272         struct compressor *cp = 0;
2273
2274         spin_lock(&compressor_list_lock);
2275         ce = find_comp_entry(type);
2276         if (ce != 0) {
2277                 cp = ce->comp;
2278                 if (!try_module_get(cp->owner))
2279                         cp = NULL;
2280         }
2281         spin_unlock(&compressor_list_lock);
2282         return cp;
2283 }
2284
2285 /*
2286  * Miscelleneous stuff.
2287  */
2288
2289 static void
2290 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2291 {
2292         struct slcompress *vj = ppp->vj;
2293
2294         memset(st, 0, sizeof(*st));
2295         st->p.ppp_ipackets = ppp->stats.rx_packets;
2296         st->p.ppp_ierrors = ppp->stats.rx_errors;
2297         st->p.ppp_ibytes = ppp->stats.rx_bytes;
2298         st->p.ppp_opackets = ppp->stats.tx_packets;
2299         st->p.ppp_oerrors = ppp->stats.tx_errors;
2300         st->p.ppp_obytes = ppp->stats.tx_bytes;
2301         if (vj == 0)
2302                 return;
2303         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2304         st->vj.vjs_compressed = vj->sls_o_compressed;
2305         st->vj.vjs_searches = vj->sls_o_searches;
2306         st->vj.vjs_misses = vj->sls_o_misses;
2307         st->vj.vjs_errorin = vj->sls_i_error;
2308         st->vj.vjs_tossed = vj->sls_i_tossed;
2309         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2310         st->vj.vjs_compressedin = vj->sls_i_compressed;
2311 }
2312
2313 /*
2314  * Stuff for handling the lists of ppp units and channels
2315  * and for initialization.
2316  */
2317
2318 /*
2319  * Create a new ppp interface unit.  Fails if it can't allocate memory
2320  * or if there is already a unit with the requested number.
2321  * unit == -1 means allocate a new number.
2322  */
2323 static struct ppp *
2324 ppp_create_interface(int unit, int *retp)
2325 {
2326         struct ppp *ppp;
2327         struct net_device *dev = NULL;
2328         int ret = -ENOMEM;
2329         int i;
2330
2331         ppp = kmalloc(sizeof(struct ppp), GFP_KERNEL);
2332         if (!ppp)
2333                 goto out;
2334         dev = alloc_netdev(0, "", ppp_setup);
2335         if (!dev)
2336                 goto out1;
2337         memset(ppp, 0, sizeof(struct ppp));
2338
2339         ppp->mru = PPP_MRU;
2340         init_ppp_file(&ppp->file, INTERFACE);
2341         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2342         for (i = 0; i < NUM_NP; ++i)
2343                 ppp->npmode[i] = NPMODE_PASS;
2344         INIT_LIST_HEAD(&ppp->channels);
2345         spin_lock_init(&ppp->rlock);
2346         spin_lock_init(&ppp->wlock);
2347 #ifdef CONFIG_PPP_MULTILINK
2348         ppp->minseq = -1;
2349         skb_queue_head_init(&ppp->mrq);
2350 #endif /* CONFIG_PPP_MULTILINK */
2351         ppp->dev = dev;
2352         dev->priv = ppp;
2353
2354         dev->hard_start_xmit = ppp_start_xmit;
2355         dev->get_stats = ppp_net_stats;
2356         dev->do_ioctl = ppp_net_ioctl;
2357
2358         ret = -EEXIST;
2359         down(&all_ppp_sem);
2360         if (unit < 0)
2361                 unit = cardmap_find_first_free(all_ppp_units);
2362         else if (cardmap_get(all_ppp_units, unit) != NULL)
2363                 goto out2;      /* unit already exists */
2364
2365         /* Initialize the new ppp unit */
2366         ppp->file.index = unit;
2367         sprintf(dev->name, "ppp%d", unit);
2368
2369         ret = register_netdev(dev);
2370         if (ret != 0) {
2371                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2372                        dev->name, ret);
2373                 goto out2;
2374         }
2375
2376         atomic_inc(&ppp_unit_count);
2377         cardmap_set(&all_ppp_units, unit, ppp);
2378         up(&all_ppp_sem);
2379         *retp = 0;
2380         return ppp;
2381
2382 out2:
2383         up(&all_ppp_sem);
2384         free_netdev(dev);
2385 out1:
2386         kfree(ppp);
2387 out:
2388         *retp = ret;
2389         return NULL;
2390 }
2391
2392 /*
2393  * Initialize a ppp_file structure.
2394  */
2395 static void
2396 init_ppp_file(struct ppp_file *pf, int kind)
2397 {
2398         pf->kind = kind;
2399         skb_queue_head_init(&pf->xq);
2400         skb_queue_head_init(&pf->rq);
2401         atomic_set(&pf->refcnt, 1);
2402         init_waitqueue_head(&pf->rwait);
2403 }
2404
2405 /*
2406  * Take down a ppp interface unit - called when the owning file
2407  * (the one that created the unit) is closed or detached.
2408  */
2409 static void ppp_shutdown_interface(struct ppp *ppp)
2410 {
2411         struct net_device *dev;
2412
2413         down(&all_ppp_sem);
2414         ppp_lock(ppp);
2415         dev = ppp->dev;
2416         ppp->dev = 0;
2417         ppp_unlock(ppp);
2418         /* This will call dev_close() for us. */
2419         if (dev) {
2420                 unregister_netdev(dev);
2421                 free_netdev(dev);
2422         }
2423         cardmap_set(&all_ppp_units, ppp->file.index, NULL);
2424         ppp->file.dead = 1;
2425         ppp->owner = NULL;
2426         wake_up_interruptible(&ppp->file.rwait);
2427         up(&all_ppp_sem);
2428 }
2429
2430 /*
2431  * Free the memory used by a ppp unit.  This is only called once
2432  * there are no channels connected to the unit and no file structs
2433  * that reference the unit.
2434  */
2435 static void ppp_destroy_interface(struct ppp *ppp)
2436 {
2437         atomic_dec(&ppp_unit_count);
2438
2439         if (!ppp->file.dead || ppp->n_channels) {
2440                 /* "can't happen" */
2441                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2442                        "n_channels=%d !\n", ppp, ppp->file.dead,
2443                        ppp->n_channels);
2444                 return;
2445         }
2446
2447         ppp_ccp_closed(ppp);
2448         if (ppp->vj) {
2449                 slhc_free(ppp->vj);
2450                 ppp->vj = 0;
2451         }
2452         skb_queue_purge(&ppp->file.xq);
2453         skb_queue_purge(&ppp->file.rq);
2454 #ifdef CONFIG_PPP_MULTILINK
2455         skb_queue_purge(&ppp->mrq);
2456 #endif /* CONFIG_PPP_MULTILINK */
2457 #ifdef CONFIG_PPP_FILTER
2458         if (ppp->pass_filter) {
2459                 kfree(ppp->pass_filter);
2460                 ppp->pass_filter = NULL;
2461         }
2462         if (ppp->active_filter) {
2463                 kfree(ppp->active_filter);
2464                 ppp->active_filter = 0;
2465         }
2466 #endif /* CONFIG_PPP_FILTER */
2467
2468         kfree(ppp);
2469 }
2470
2471 /*
2472  * Locate an existing ppp unit.
2473  * The caller should have locked the all_ppp_sem.
2474  */
2475 static struct ppp *
2476 ppp_find_unit(int unit)
2477 {
2478         return cardmap_get(all_ppp_units, unit);
2479 }
2480
2481 /*
2482  * Locate an existing ppp channel.
2483  * The caller should have locked the all_channels_lock.
2484  * First we look in the new_channels list, then in the
2485  * all_channels list.  If found in the new_channels list,
2486  * we move it to the all_channels list.  This is for speed
2487  * when we have a lot of channels in use.
2488  */
2489 static struct channel *
2490 ppp_find_channel(int unit)
2491 {
2492         struct channel *pch;
2493         struct list_head *list;
2494
2495         list = &new_channels;
2496         while ((list = list->next) != &new_channels) {
2497                 pch = list_entry(list, struct channel, list);
2498                 if (pch->file.index == unit) {
2499                         list_del(&pch->list);
2500                         list_add(&pch->list, &all_channels);
2501                         return pch;
2502                 }
2503         }
2504         list = &all_channels;
2505         while ((list = list->next) != &all_channels) {
2506                 pch = list_entry(list, struct channel, list);
2507                 if (pch->file.index == unit)
2508                         return pch;
2509         }
2510         return 0;
2511 }
2512
2513 /*
2514  * Connect a PPP channel to a PPP interface unit.
2515  */
2516 static int
2517 ppp_connect_channel(struct channel *pch, int unit)
2518 {
2519         struct ppp *ppp;
2520         int ret = -ENXIO;
2521         int hdrlen;
2522
2523         down(&all_ppp_sem);
2524         ppp = ppp_find_unit(unit);
2525         if (ppp == 0)
2526                 goto out;
2527         write_lock_bh(&pch->upl);
2528         ret = -EINVAL;
2529         if (pch->ppp != 0)
2530                 goto outl;
2531
2532         ppp_lock(ppp);
2533         if (pch->file.hdrlen > ppp->file.hdrlen)
2534                 ppp->file.hdrlen = pch->file.hdrlen;
2535         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2536         if (ppp->dev && hdrlen > ppp->dev->hard_header_len)
2537                 ppp->dev->hard_header_len = hdrlen;
2538         list_add_tail(&pch->clist, &ppp->channels);
2539         ++ppp->n_channels;
2540         pch->ppp = ppp;
2541         atomic_inc(&ppp->file.refcnt);
2542         ppp_unlock(ppp);
2543         ret = 0;
2544
2545  outl:
2546         write_unlock_bh(&pch->upl);
2547  out:
2548         up(&all_ppp_sem);
2549         return ret;
2550 }
2551
2552 /*
2553  * Disconnect a channel from its ppp unit.
2554  */
2555 static int
2556 ppp_disconnect_channel(struct channel *pch)
2557 {
2558         struct ppp *ppp;
2559         int err = -EINVAL;
2560
2561         write_lock_bh(&pch->upl);
2562         ppp = pch->ppp;
2563         pch->ppp = NULL;
2564         write_unlock_bh(&pch->upl);
2565         if (ppp != 0) {
2566                 /* remove it from the ppp unit's list */
2567                 ppp_lock(ppp);
2568                 list_del(&pch->clist);
2569                 --ppp->n_channels;
2570                 ppp_unlock(ppp);
2571                 if (atomic_dec_and_test(&ppp->file.refcnt))
2572                         ppp_destroy_interface(ppp);
2573                 err = 0;
2574         }
2575         return err;
2576 }
2577
2578 /*
2579  * Free up the resources used by a ppp channel.
2580  */
2581 static void ppp_destroy_channel(struct channel *pch)
2582 {
2583         atomic_dec(&channel_count);
2584
2585         if (!pch->file.dead) {
2586                 /* "can't happen" */
2587                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2588                        pch);
2589                 return;
2590         }
2591         skb_queue_purge(&pch->file.xq);
2592         skb_queue_purge(&pch->file.rq);
2593         kfree(pch);
2594 }
2595
2596 static void __exit ppp_cleanup(void)
2597 {
2598         /* should never happen */
2599         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2600                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2601         cardmap_destroy(&all_ppp_units);
2602         if (unregister_chrdev(PPP_MAJOR, "ppp") != 0)
2603                 printk(KERN_ERR "PPP: failed to unregister PPP device\n");
2604         devfs_remove("ppp");
2605         class_simple_device_remove(MKDEV(PPP_MAJOR, 0));
2606         class_simple_destroy(ppp_class);
2607 }
2608
2609 /*
2610  * Cardmap implementation.
2611  */
2612 static void *cardmap_get(struct cardmap *map, unsigned int nr)
2613 {
2614         struct cardmap *p;
2615         int i;
2616
2617         for (p = map; p != NULL; ) {
2618                 if ((i = nr >> p->shift) >= CARDMAP_WIDTH)
2619                         return NULL;
2620                 if (p->shift == 0)
2621                         return p->ptr[i];
2622                 nr &= ~(CARDMAP_MASK << p->shift);
2623                 p = p->ptr[i];
2624         }
2625         return NULL;
2626 }
2627
2628 static void cardmap_set(struct cardmap **pmap, unsigned int nr, void *ptr)
2629 {
2630         struct cardmap *p;
2631         int i;
2632
2633         p = *pmap;
2634         if (p == NULL || (nr >> p->shift) >= CARDMAP_WIDTH) {
2635                 do {
2636                         /* need a new top level */
2637                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2638                         memset(np, 0, sizeof(*np));
2639                         np->ptr[0] = p;
2640                         if (p != NULL) {
2641                                 np->shift = p->shift + CARDMAP_ORDER;
2642                                 p->parent = np;
2643                         } else
2644                                 np->shift = 0;
2645                         p = np;
2646                 } while ((nr >> p->shift) >= CARDMAP_WIDTH);
2647                 *pmap = p;
2648         }
2649         while (p->shift > 0) {
2650                 i = (nr >> p->shift) & CARDMAP_MASK;
2651                 if (p->ptr[i] == NULL) {
2652                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2653                         memset(np, 0, sizeof(*np));
2654                         np->shift = p->shift - CARDMAP_ORDER;
2655                         np->parent = p;
2656                         p->ptr[i] = np;
2657                 }
2658                 if (ptr == NULL)
2659                         clear_bit(i, &p->inuse);
2660                 p = p->ptr[i];
2661         }
2662         i = nr & CARDMAP_MASK;
2663         p->ptr[i] = ptr;
2664         if (ptr != NULL)
2665                 set_bit(i, &p->inuse);
2666         else
2667                 clear_bit(i, &p->inuse);
2668 }
2669
2670 static unsigned int cardmap_find_first_free(struct cardmap *map)
2671 {
2672         struct cardmap *p;
2673         unsigned int nr = 0;
2674         int i;
2675
2676         if ((p = map) == NULL)
2677                 return 0;
2678         for (;;) {
2679                 i = find_first_zero_bit(&p->inuse, CARDMAP_WIDTH);
2680                 if (i >= CARDMAP_WIDTH) {
2681                         if (p->parent == NULL)
2682                                 return CARDMAP_WIDTH << p->shift;
2683                         p = p->parent;
2684                         i = (nr >> p->shift) & CARDMAP_MASK;
2685                         set_bit(i, &p->inuse);
2686                         continue;
2687                 }
2688                 nr = (nr & (~CARDMAP_MASK << p->shift)) | (i << p->shift);
2689                 if (p->shift == 0 || p->ptr[i] == NULL)
2690                         return nr;
2691                 p = p->ptr[i];
2692         }
2693 }
2694
2695 static void cardmap_destroy(struct cardmap **pmap)
2696 {
2697         struct cardmap *p, *np;
2698         int i;
2699
2700         for (p = *pmap; p != NULL; p = np) {
2701                 if (p->shift != 0) {
2702                         for (i = 0; i < CARDMAP_WIDTH; ++i)
2703                                 if (p->ptr[i] != NULL)
2704                                         break;
2705                         if (i < CARDMAP_WIDTH) {
2706                                 np = p->ptr[i];
2707                                 p->ptr[i] = NULL;
2708                                 continue;
2709                         }
2710                 }
2711                 np = p->parent;
2712                 kfree(p);
2713         }
2714         *pmap = NULL;
2715 }
2716
2717 /* Module/initialization stuff */
2718
2719 module_init(ppp_init);
2720 module_exit(ppp_cleanup);
2721
2722 EXPORT_SYMBOL(ppp_register_channel);
2723 EXPORT_SYMBOL(ppp_unregister_channel);
2724 EXPORT_SYMBOL(ppp_channel_index);
2725 EXPORT_SYMBOL(ppp_unit_number);
2726 EXPORT_SYMBOL(ppp_input);
2727 EXPORT_SYMBOL(ppp_input_error);
2728 EXPORT_SYMBOL(ppp_output_wakeup);
2729 EXPORT_SYMBOL(ppp_register_compressor);
2730 EXPORT_SYMBOL(ppp_unregister_compressor);
2731 EXPORT_SYMBOL(all_ppp_units); /* for debugging */
2732 EXPORT_SYMBOL(all_channels); /* for debugging */
2733 MODULE_LICENSE("GPL");
2734 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2735 MODULE_ALIAS("/dev/ppp");