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