drivers/net/ppp/ppp_generic.c

   1 /*
   2  * Generic PPP layer for Linux.
   3  *
   4  * Copyright 1999-2002 Paul Mackerras.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  *
  11  * The generic PPP layer handles the PPP network interfaces, the
  12  * /dev/ppp device, packet and VJ compression, and multilink.
  13  * It talks to PPP `channels' via the interface defined in
  14  * include/linux/ppp_channel.h.  Channels provide the basic means for
  15  * sending and receiving PPP frames on some kind of communications
  16  * channel.
  17  *
  18  * Part of the code in this driver was inspired by the old async-only
  19  * PPP driver, written by Michael Callahan and Al Longyear, and
  20  * subsequently hacked by Paul Mackerras.
  21  *
  22  * ==FILEVERSION 20041108==
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/kmod.h>
  28 #include <linux/init.h>
  29 #include <linux/list.h>
  30 #include <linux/idr.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/poll.h>
  33 #include <linux/ppp_defs.h>
  34 #include <linux/filter.h>
  35 #include <linux/ppp-ioctl.h>
  36 #include <linux/ppp_channel.h>
  37 #include <linux/ppp-comp.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/rtnetlink.h>
  40 #include <linux/if_arp.h>
  41 #include <linux/ip.h>
  42 #include <linux/tcp.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/rwsem.h>
  45 #include <linux/stddef.h>
  46 #include <linux/device.h>
  47 #include <linux/mutex.h>
  48 #include <linux/slab.h>
  49 #include <asm/unaligned.h>
  50 #include <net/slhc_vj.h>
  51 #include <linux/atomic.h>
  52
  53 #include <linux/nsproxy.h>
  54 #include <net/net_namespace.h>
  55 #include <net/netns/generic.h>
  56
  57 #define PPP_VERSION     "2.4.2"
  58
  59 /*
  60  * Network protocols we support.
  61  */
  62 #define NP_IP   0               /* Internet Protocol V4 */
  63 #define NP_IPV6 1               /* Internet Protocol V6 */
  64 #define NP_IPX  2               /* IPX protocol */
  65 #define NP_AT   3               /* Appletalk protocol */
  66 #define NP_MPLS_UC 4            /* MPLS unicast */
  67 #define NP_MPLS_MC 5            /* MPLS multicast */
  68 #define NUM_NP  6               /* Number of NPs. */
  69
  70 #define MPHDRLEN        6       /* multilink protocol header length */
  71 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  72
  73 /*
  74  * An instance of /dev/ppp can be associated with either a ppp
  75  * interface unit or a ppp channel.  In both cases, file->private_data
  76  * points to one of these.
  77  */
  78 struct ppp_file {
  79         enum {
  80                 INTERFACE=1, CHANNEL
  81         }               kind;
  82         struct sk_buff_head xq;         /* pppd transmit queue */
  83         struct sk_buff_head rq;         /* receive queue for pppd */
  84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  86         int             hdrlen;         /* space to leave for headers */
  87         int             index;          /* interface unit / channel number */
  88         int             dead;           /* unit/channel has been shut down */
  89 };
  90
  91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  92
  93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  95
  96 /*
  97  * Data structure 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 DEFINE_MUTEX(ppp_mutex);
 184 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 185 static atomic_t channel_count = ATOMIC_INIT(0);
 186
 187 /* per-net private data for this module */
 188 static int ppp_net_id __read_mostly;
 189 struct ppp_net {
 190         /* units to ppp mapping */
 191         struct idr units_idr;
 192
 193         /*
 194          * all_ppp_mutex protects the units_idr mapping.
 195          * It also ensures that finding a ppp unit in the units_idr
 196          * map and updating its file.refcnt field is atomic.
 197          */
 198         struct mutex all_ppp_mutex;
 199
 200         /* channels */
 201         struct list_head all_channels;
 202         struct list_head new_channels;
 203         int last_channel_index;
 204
 205         /*
 206          * all_channels_lock protects all_channels and
 207          * last_channel_index, and the atomicity of find
 208          * a channel and updating its file.refcnt field.
 209          */
 210         spinlock_t all_channels_lock;
 211 };
 212
 213 /* Get the PPP protocol number from a skb */
 214 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 215
 216 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 217 #define PPP_MAX_RQLEN   32
 218
 219 /*
 220  * Maximum number of multilink fragments queued up.
 221  * This has to be large enough to cope with the maximum latency of
 222  * the slowest channel relative to the others.  Strictly it should
 223  * depend on the number of channels and their characteristics.
 224  */
 225 #define PPP_MP_MAX_QLEN 128
 226
 227 /* Multilink header bits. */
 228 #define B       0x80            /* this fragment begins a packet */
 229 #define E       0x40            /* this fragment ends a packet */
 230
 231 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 232 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 233 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 234
 235 /* Prototypes. */
 236 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 237                         struct file *file, unsigned int cmd, unsigned long arg);
 238 static void ppp_xmit_process(struct ppp *ppp);
 239 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 240 static void ppp_push(struct ppp *ppp);
 241 static void ppp_channel_push(struct channel *pch);
 242 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 243                               struct channel *pch);
 244 static void ppp_receive_error(struct ppp *ppp);
 245 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 246 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 247                                             struct sk_buff *skb);
 248 #ifdef CONFIG_PPP_MULTILINK
 249 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 250                                 struct channel *pch);
 251 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 252 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 253 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 254 #endif /* CONFIG_PPP_MULTILINK */
 255 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 256 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 257 static void ppp_ccp_closed(struct ppp *ppp);
 258 static struct compressor *find_compressor(int type);
 259 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 260 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 261 static void init_ppp_file(struct ppp_file *pf, int kind);
 262 static void ppp_shutdown_interface(struct ppp *ppp);
 263 static void ppp_destroy_interface(struct ppp *ppp);
 264 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 265 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 266 static int ppp_connect_channel(struct channel *pch, int unit);
 267 static int ppp_disconnect_channel(struct channel *pch);
 268 static void ppp_destroy_channel(struct channel *pch);
 269 static int unit_get(struct idr *p, void *ptr);
 270 static int unit_set(struct idr *p, void *ptr, int n);
 271 static void unit_put(struct idr *p, int n);
 272 static void *unit_find(struct idr *p, int n);
 273
 274 static struct class *ppp_class;
 275
 276 /* per net-namespace data */
 277 static inline struct ppp_net *ppp_pernet(struct net *net)
 278 {
 279         BUG_ON(!net);
 280
 281         return net_generic(net, ppp_net_id);
 282 }
 283
 284 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 285 static inline int proto_to_npindex(int proto)
 286 {
 287         switch (proto) {
 288         case PPP_IP:
 289                 return NP_IP;
 290         case PPP_IPV6:
 291                 return NP_IPV6;
 292         case PPP_IPX:
 293                 return NP_IPX;
 294         case PPP_AT:
 295                 return NP_AT;
 296         case PPP_MPLS_UC:
 297                 return NP_MPLS_UC;
 298         case PPP_MPLS_MC:
 299                 return NP_MPLS_MC;
 300         }
 301         return -EINVAL;
 302 }
 303
 304 /* Translates an NP index into a PPP protocol number */
 305 static const int npindex_to_proto[NUM_NP] = {
 306         PPP_IP,
 307         PPP_IPV6,
 308         PPP_IPX,
 309         PPP_AT,
 310         PPP_MPLS_UC,
 311         PPP_MPLS_MC,
 312 };
 313
 314 /* Translates an ethertype into an NP index */
 315 static inline int ethertype_to_npindex(int ethertype)
 316 {
 317         switch (ethertype) {
 318         case ETH_P_IP:
 319                 return NP_IP;
 320         case ETH_P_IPV6:
 321                 return NP_IPV6;
 322         case ETH_P_IPX:
 323                 return NP_IPX;
 324         case ETH_P_PPPTALK:
 325         case ETH_P_ATALK:
 326                 return NP_AT;
 327         case ETH_P_MPLS_UC:
 328                 return NP_MPLS_UC;
 329         case ETH_P_MPLS_MC:
 330                 return NP_MPLS_MC;
 331         }
 332         return -1;
 333 }
 334
 335 /* Translates an NP index into an ethertype */
 336 static const int npindex_to_ethertype[NUM_NP] = {
 337         ETH_P_IP,
 338         ETH_P_IPV6,
 339         ETH_P_IPX,
 340         ETH_P_PPPTALK,
 341         ETH_P_MPLS_UC,
 342         ETH_P_MPLS_MC,
 343 };
 344
 345 /*
 346  * Locking shorthand.
 347  */
 348 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 349 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 350 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 351 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 352 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 353                                      ppp_recv_lock(ppp); } while (0)
 354 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 355                                      ppp_xmit_unlock(ppp); } while (0)
 356
 357 /*
 358  * /dev/ppp device routines.
 359  * The /dev/ppp device is used by pppd to control the ppp unit.
 360  * It supports the read, write, ioctl and poll functions.
 361  * Open instances of /dev/ppp can be in one of three states:
 362  * unattached, attached to a ppp unit, or attached to a ppp channel.
 363  */
 364 static int ppp_open(struct inode *inode, struct file *file)
 365 {
 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         struct iovec iov;
 408
 409         ret = count;
 410
 411         if (!pf)
 412                 return -ENXIO;
 413         add_wait_queue(&pf->rwait, &wait);
 414         for (;;) {
 415                 set_current_state(TASK_INTERRUPTIBLE);
 416                 skb = skb_dequeue(&pf->rq);
 417                 if (skb)
 418                         break;
 419                 ret = 0;
 420                 if (pf->dead)
 421                         break;
 422                 if (pf->kind == INTERFACE) {
 423                         /*
 424                          * Return 0 (EOF) on an interface that has no
 425                          * channels connected, unless it is looping
 426                          * network traffic (demand mode).
 427                          */
 428                         struct ppp *ppp = PF_TO_PPP(pf);
 429                         if (ppp->n_channels == 0 &&
 430                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 431                                 break;
 432                 }
 433                 ret = -EAGAIN;
 434                 if (file->f_flags & O_NONBLOCK)
 435                         break;
 436                 ret = -ERESTARTSYS;
 437                 if (signal_pending(current))
 438                         break;
 439                 schedule();
 440         }
 441         set_current_state(TASK_RUNNING);
 442         remove_wait_queue(&pf->rwait, &wait);
 443
 444         if (!skb)
 445                 goto out;
 446
 447         ret = -EOVERFLOW;
 448         if (skb->len > count)
 449                 goto outf;
 450         ret = -EFAULT;
 451         iov.iov_base = buf;
 452         iov.iov_len = count;
 453         if (skb_copy_datagram_iovec(skb, 0, &iov, skb->len))
 454                 goto outf;
 455         ret = skb->len;
 456
 457  outf:
 458         kfree_skb(skb);
 459  out:
 460         return ret;
 461 }
 462
 463 static ssize_t ppp_write(struct file *file, const char __user *buf,
 464                          size_t count, loff_t *ppos)
 465 {
 466         struct ppp_file *pf = file->private_data;
 467         struct sk_buff *skb;
 468         ssize_t ret;
 469
 470         if (!pf)
 471                 return -ENXIO;
 472         ret = -ENOMEM;
 473         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 474         if (!skb)
 475                 goto out;
 476         skb_reserve(skb, pf->hdrlen);
 477         ret = -EFAULT;
 478         if (copy_from_user(skb_put(skb, count), buf, count)) {
 479                 kfree_skb(skb);
 480                 goto out;
 481         }
 482
 483         skb_queue_tail(&pf->xq, skb);
 484
 485         switch (pf->kind) {
 486         case INTERFACE:
 487                 ppp_xmit_process(PF_TO_PPP(pf));
 488                 break;
 489         case CHANNEL:
 490                 ppp_channel_push(PF_TO_CHANNEL(pf));
 491                 break;
 492         }
 493
 494         ret = count;
 495
 496  out:
 497         return ret;
 498 }
 499
 500 /* No kernel lock - fine */
 501 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 502 {
 503         struct ppp_file *pf = file->private_data;
 504         unsigned int mask;
 505
 506         if (!pf)
 507                 return 0;
 508         poll_wait(file, &pf->rwait, wait);
 509         mask = POLLOUT | POLLWRNORM;
 510         if (skb_peek(&pf->rq))
 511                 mask |= POLLIN | POLLRDNORM;
 512         if (pf->dead)
 513                 mask |= POLLHUP;
 514         else if (pf->kind == INTERFACE) {
 515                 /* see comment in ppp_read */
 516                 struct ppp *ppp = PF_TO_PPP(pf);
 517                 if (ppp->n_channels == 0 &&
 518                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 519                         mask |= POLLIN | POLLRDNORM;
 520         }
 521
 522         return mask;
 523 }
 524
 525 #ifdef CONFIG_PPP_FILTER
 526 static int get_filter(void __user *arg, struct sock_filter **p)
 527 {
 528         struct sock_fprog uprog;
 529         struct sock_filter *code = NULL;
 530         int len, err;
 531
 532         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 533                 return -EFAULT;
 534
 535         if (!uprog.len) {
 536                 *p = NULL;
 537                 return 0;
 538         }
 539
 540         len = uprog.len * sizeof(struct sock_filter);
 541         code = memdup_user(uprog.filter, len);
 542         if (IS_ERR(code))
 543                 return PTR_ERR(code);
 544
 545         err = sk_chk_filter(code, uprog.len);
 546         if (err) {
 547                 kfree(code);
 548                 return err;
 549         }
 550
 551         *p = code;
 552         return uprog.len;
 553 }
 554 #endif /* CONFIG_PPP_FILTER */
 555
 556 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 557 {
 558         struct ppp_file *pf = file->private_data;
 559         struct ppp *ppp;
 560         int err = -EFAULT, val, val2, i;
 561         struct ppp_idle idle;
 562         struct npioctl npi;
 563         int unit, cflags;
 564         struct slcompress *vj;
 565         void __user *argp = (void __user *)arg;
 566         int __user *p = argp;
 567
 568         if (!pf)
 569                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
 570                                         pf, file, cmd, arg);
 571
 572         if (cmd == PPPIOCDETACH) {
 573                 /*
 574                  * We have to be careful here... if the file descriptor
 575                  * has been dup'd, we could have another process in the
 576                  * middle of a poll using the same file *, so we had
 577                  * better not free the interface data structures -
 578                  * instead we fail the ioctl.  Even in this case, we
 579                  * shut down the interface if we are the owner of it.
 580                  * Actually, we should get rid of PPPIOCDETACH, userland
 581                  * (i.e. pppd) could achieve the same effect by closing
 582                  * this fd and reopening /dev/ppp.
 583                  */
 584                 err = -EINVAL;
 585                 mutex_lock(&ppp_mutex);
 586                 if (pf->kind == INTERFACE) {
 587                         ppp = PF_TO_PPP(pf);
 588                         if (file == ppp->owner)
 589                                 ppp_shutdown_interface(ppp);
 590                 }
 591                 if (atomic_long_read(&file->f_count) <= 2) {
 592                         ppp_release(NULL, file);
 593                         err = 0;
 594                 } else
 595                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 596                                 atomic_long_read(&file->f_count));
 597                 mutex_unlock(&ppp_mutex);
 598                 return err;
 599         }
 600
 601         if (pf->kind == CHANNEL) {
 602                 struct channel *pch;
 603                 struct ppp_channel *chan;
 604
 605                 mutex_lock(&ppp_mutex);
 606                 pch = PF_TO_CHANNEL(pf);
 607
 608                 switch (cmd) {
 609                 case PPPIOCCONNECT:
 610                         if (get_user(unit, p))
 611                                 break;
 612                         err = ppp_connect_channel(pch, unit);
 613                         break;
 614
 615                 case PPPIOCDISCONN:
 616                         err = ppp_disconnect_channel(pch);
 617                         break;
 618
 619                 default:
 620                         down_read(&pch->chan_sem);
 621                         chan = pch->chan;
 622                         err = -ENOTTY;
 623                         if (chan && chan->ops->ioctl)
 624                                 err = chan->ops->ioctl(chan, cmd, arg);
 625                         up_read(&pch->chan_sem);
 626                 }
 627                 mutex_unlock(&ppp_mutex);
 628                 return err;
 629         }
 630
 631         if (pf->kind != INTERFACE) {
 632                 /* can't happen */
 633                 pr_err("PPP: not interface or channel??\n");
 634                 return -EINVAL;
 635         }
 636
 637         mutex_lock(&ppp_mutex);
 638         ppp = PF_TO_PPP(pf);
 639         switch (cmd) {
 640         case PPPIOCSMRU:
 641                 if (get_user(val, p))
 642                         break;
 643                 ppp->mru = val;
 644                 err = 0;
 645                 break;
 646
 647         case PPPIOCSFLAGS:
 648                 if (get_user(val, p))
 649                         break;
 650                 ppp_lock(ppp);
 651                 cflags = ppp->flags & ~val;
 652                 ppp->flags = val & SC_FLAG_BITS;
 653                 ppp_unlock(ppp);
 654                 if (cflags & SC_CCP_OPEN)
 655                         ppp_ccp_closed(ppp);
 656                 err = 0;
 657                 break;
 658
 659         case PPPIOCGFLAGS:
 660                 val = ppp->flags | ppp->xstate | ppp->rstate;
 661                 if (put_user(val, p))
 662                         break;
 663                 err = 0;
 664                 break;
 665
 666         case PPPIOCSCOMPRESS:
 667                 err = ppp_set_compress(ppp, arg);
 668                 break;
 669
 670         case PPPIOCGUNIT:
 671                 if (put_user(ppp->file.index, p))
 672                         break;
 673                 err = 0;
 674                 break;
 675
 676         case PPPIOCSDEBUG:
 677                 if (get_user(val, p))
 678                         break;
 679                 ppp->debug = val;
 680                 err = 0;
 681                 break;
 682
 683         case PPPIOCGDEBUG:
 684                 if (put_user(ppp->debug, p))
 685                         break;
 686                 err = 0;
 687                 break;
 688
 689         case PPPIOCGIDLE:
 690                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 691                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 692                 if (copy_to_user(argp, &idle, sizeof(idle)))
 693                         break;
 694                 err = 0;
 695                 break;
 696
 697         case PPPIOCSMAXCID:
 698                 if (get_user(val, p))
 699                         break;
 700                 val2 = 15;
 701                 if ((val >> 16) != 0) {
 702                         val2 = val >> 16;
 703                         val &= 0xffff;
 704                 }
 705                 vj = slhc_init(val2+1, val+1);
 706                 if (!vj) {
 707                         netdev_err(ppp->dev,
 708                                    "PPP: no memory (VJ compressor)\n");
 709                         err = -ENOMEM;
 710                         break;
 711                 }
 712                 ppp_lock(ppp);
 713                 if (ppp->vj)
 714                         slhc_free(ppp->vj);
 715                 ppp->vj = vj;
 716                 ppp_unlock(ppp);
 717                 err = 0;
 718                 break;
 719
 720         case PPPIOCGNPMODE:
 721         case PPPIOCSNPMODE:
 722                 if (copy_from_user(&npi, argp, sizeof(npi)))
 723                         break;
 724                 err = proto_to_npindex(npi.protocol);
 725                 if (err < 0)
 726                         break;
 727                 i = err;
 728                 if (cmd == PPPIOCGNPMODE) {
 729                         err = -EFAULT;
 730                         npi.mode = ppp->npmode[i];
 731                         if (copy_to_user(argp, &npi, sizeof(npi)))
 732                                 break;
 733                 } else {
 734                         ppp->npmode[i] = npi.mode;
 735                         /* we may be able to transmit more packets now (??) */
 736                         netif_wake_queue(ppp->dev);
 737                 }
 738                 err = 0;
 739                 break;
 740
 741 #ifdef CONFIG_PPP_FILTER
 742         case PPPIOCSPASS:
 743         {
 744                 struct sock_filter *code;
 745                 err = get_filter(argp, &code);
 746                 if (err >= 0) {
 747                         ppp_lock(ppp);
 748                         kfree(ppp->pass_filter);
 749                         ppp->pass_filter = code;
 750                         ppp->pass_len = err;
 751                         ppp_unlock(ppp);
 752                         err = 0;
 753                 }
 754                 break;
 755         }
 756         case PPPIOCSACTIVE:
 757         {
 758                 struct sock_filter *code;
 759                 err = get_filter(argp, &code);
 760                 if (err >= 0) {
 761                         ppp_lock(ppp);
 762                         kfree(ppp->active_filter);
 763                         ppp->active_filter = code;
 764                         ppp->active_len = err;
 765                         ppp_unlock(ppp);
 766                         err = 0;
 767                 }
 768                 break;
 769         }
 770 #endif /* CONFIG_PPP_FILTER */
 771
 772 #ifdef CONFIG_PPP_MULTILINK
 773         case PPPIOCSMRRU:
 774                 if (get_user(val, p))
 775                         break;
 776                 ppp_recv_lock(ppp);
 777                 ppp->mrru = val;
 778                 ppp_recv_unlock(ppp);
 779                 err = 0;
 780                 break;
 781 #endif /* CONFIG_PPP_MULTILINK */
 782
 783         default:
 784                 err = -ENOTTY;
 785         }
 786         mutex_unlock(&ppp_mutex);
 787         return err;
 788 }
 789
 790 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 791                         struct file *file, unsigned int cmd, unsigned long arg)
 792 {
 793         int unit, err = -EFAULT;
 794         struct ppp *ppp;
 795         struct channel *chan;
 796         struct ppp_net *pn;
 797         int __user *p = (int __user *)arg;
 798
 799         mutex_lock(&ppp_mutex);
 800         switch (cmd) {
 801         case PPPIOCNEWUNIT:
 802                 /* Create a new ppp unit */
 803                 if (get_user(unit, p))
 804                         break;
 805                 ppp = ppp_create_interface(net, unit, &err);
 806                 if (!ppp)
 807                         break;
 808                 file->private_data = &ppp->file;
 809                 ppp->owner = file;
 810                 err = -EFAULT;
 811                 if (put_user(ppp->file.index, p))
 812                         break;
 813                 err = 0;
 814                 break;
 815
 816         case PPPIOCATTACH:
 817                 /* Attach to an existing ppp unit */
 818                 if (get_user(unit, p))
 819                         break;
 820                 err = -ENXIO;
 821                 pn = ppp_pernet(net);
 822                 mutex_lock(&pn->all_ppp_mutex);
 823                 ppp = ppp_find_unit(pn, unit);
 824                 if (ppp) {
 825                         atomic_inc(&ppp->file.refcnt);
 826                         file->private_data = &ppp->file;
 827                         err = 0;
 828                 }
 829                 mutex_unlock(&pn->all_ppp_mutex);
 830                 break;
 831
 832         case PPPIOCATTCHAN:
 833                 if (get_user(unit, p))
 834                         break;
 835                 err = -ENXIO;
 836                 pn = ppp_pernet(net);
 837                 spin_lock_bh(&pn->all_channels_lock);
 838                 chan = ppp_find_channel(pn, unit);
 839                 if (chan) {
 840                         atomic_inc(&chan->file.refcnt);
 841                         file->private_data = &chan->file;
 842                         err = 0;
 843                 }
 844                 spin_unlock_bh(&pn->all_channels_lock);
 845                 break;
 846
 847         default:
 848                 err = -ENOTTY;
 849         }
 850         mutex_unlock(&ppp_mutex);
 851         return err;
 852 }
 853
 854 static const struct file_operations ppp_device_fops = {
 855         .owner          = THIS_MODULE,
 856         .read           = ppp_read,
 857         .write          = ppp_write,
 858         .poll           = ppp_poll,
 859         .unlocked_ioctl = ppp_ioctl,
 860         .open           = ppp_open,
 861         .release        = ppp_release,
 862         .llseek         = noop_llseek,
 863 };
 864
 865 static __net_init int ppp_init_net(struct net *net)
 866 {
 867         struct ppp_net *pn = net_generic(net, ppp_net_id);
 868
 869         idr_init(&pn->units_idr);
 870         mutex_init(&pn->all_ppp_mutex);
 871
 872         INIT_LIST_HEAD(&pn->all_channels);
 873         INIT_LIST_HEAD(&pn->new_channels);
 874
 875         spin_lock_init(&pn->all_channels_lock);
 876
 877         return 0;
 878 }
 879
 880 static __net_exit void ppp_exit_net(struct net *net)
 881 {
 882         struct ppp_net *pn = net_generic(net, ppp_net_id);
 883
 884         idr_destroy(&pn->units_idr);
 885 }
 886
 887 static struct pernet_operations ppp_net_ops = {
 888         .init = ppp_init_net,
 889         .exit = ppp_exit_net,
 890         .id   = &ppp_net_id,
 891         .size = sizeof(struct ppp_net),
 892 };
 893
 894 #define PPP_MAJOR       108
 895
 896 /* Called at boot time if ppp is compiled into the kernel,
 897    or at module load time (from init_module) if compiled as a module. */
 898 static int __init ppp_init(void)
 899 {
 900         int err;
 901
 902         pr_info("PPP generic driver version " PPP_VERSION "\n");
 903
 904         err = register_pernet_device(&ppp_net_ops);
 905         if (err) {
 906                 pr_err("failed to register PPP pernet device (%d)\n", err);
 907                 goto out;
 908         }
 909
 910         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 911         if (err) {
 912                 pr_err("failed to register PPP device (%d)\n", err);
 913                 goto out_net;
 914         }
 915
 916         ppp_class = class_create(THIS_MODULE, "ppp");
 917         if (IS_ERR(ppp_class)) {
 918                 err = PTR_ERR(ppp_class);
 919                 goto out_chrdev;
 920         }
 921
 922         /* not a big deal if we fail here :-) */
 923         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 924
 925         return 0;
 926
 927 out_chrdev:
 928         unregister_chrdev(PPP_MAJOR, "ppp");
 929 out_net:
 930         unregister_pernet_device(&ppp_net_ops);
 931 out:
 932         return err;
 933 }
 934
 935 /*
 936  * Network interface unit routines.
 937  */
 938 static netdev_tx_t
 939 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 940 {
 941         struct ppp *ppp = netdev_priv(dev);
 942         int npi, proto;
 943         unsigned char *pp;
 944
 945         npi = ethertype_to_npindex(ntohs(skb->protocol));
 946         if (npi < 0)
 947                 goto outf;
 948
 949         /* Drop, accept or reject the packet */
 950         switch (ppp->npmode[npi]) {
 951         case NPMODE_PASS:
 952                 break;
 953         case NPMODE_QUEUE:
 954                 /* it would be nice to have a way to tell the network
 955                    system to queue this one up for later. */
 956                 goto outf;
 957         case NPMODE_DROP:
 958         case NPMODE_ERROR:
 959                 goto outf;
 960         }
 961
 962         /* Put the 2-byte PPP protocol number on the front,
 963            making sure there is room for the address and control fields. */
 964         if (skb_cow_head(skb, PPP_HDRLEN))
 965                 goto outf;
 966
 967         pp = skb_push(skb, 2);
 968         proto = npindex_to_proto[npi];
 969         put_unaligned_be16(proto, pp);
 970
 971         netif_stop_queue(dev);
 972         skb_queue_tail(&ppp->file.xq, skb);
 973         ppp_xmit_process(ppp);
 974         return NETDEV_TX_OK;
 975
 976  outf:
 977         kfree_skb(skb);
 978         ++dev->stats.tx_dropped;
 979         return NETDEV_TX_OK;
 980 }
 981
 982 static int
 983 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 984 {
 985         struct ppp *ppp = netdev_priv(dev);
 986         int err = -EFAULT;
 987         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
 988         struct ppp_stats stats;
 989         struct ppp_comp_stats cstats;
 990         char *vers;
 991
 992         switch (cmd) {
 993         case SIOCGPPPSTATS:
 994                 ppp_get_stats(ppp, &stats);
 995                 if (copy_to_user(addr, &stats, sizeof(stats)))
 996                         break;
 997                 err = 0;
 998                 break;
 999
1000         case SIOCGPPPCSTATS:
1001                 memset(&cstats, 0, sizeof(cstats));
1002                 if (ppp->xc_state)
1003                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1004                 if (ppp->rc_state)
1005                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1006                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1007                         break;
1008                 err = 0;
1009                 break;
1010
1011         case SIOCGPPPVER:
1012                 vers = PPP_VERSION;
1013                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1014                         break;
1015                 err = 0;
1016                 break;
1017
1018         default:
1019                 err = -EINVAL;
1020         }
1021
1022         return err;
1023 }
1024
1025 static const struct net_device_ops ppp_netdev_ops = {
1026         .ndo_start_xmit = ppp_start_xmit,
1027         .ndo_do_ioctl   = ppp_net_ioctl,
1028 };
1029
1030 static void ppp_setup(struct net_device *dev)
1031 {
1032         dev->netdev_ops = &ppp_netdev_ops;
1033         dev->hard_header_len = PPP_HDRLEN;
1034         dev->mtu = PPP_MRU;
1035         dev->addr_len = 0;
1036         dev->tx_queue_len = 3;
1037         dev->type = ARPHRD_PPP;
1038         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1039         dev->features |= NETIF_F_NETNS_LOCAL;
1040         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1041 }
1042
1043 /*
1044  * Transmit-side routines.
1045  */
1046
1047 /*
1048  * Called to do any work queued up on the transmit side
1049  * that can now be done.
1050  */
1051 static void
1052 ppp_xmit_process(struct ppp *ppp)
1053 {
1054         struct sk_buff *skb;
1055
1056         ppp_xmit_lock(ppp);
1057         if (!ppp->closing) {
1058                 ppp_push(ppp);
1059                 while (!ppp->xmit_pending &&
1060                        (skb = skb_dequeue(&ppp->file.xq)))
1061                         ppp_send_frame(ppp, skb);
1062                 /* If there's no work left to do, tell the core net
1063                    code that we can accept some more. */
1064                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1065                         netif_wake_queue(ppp->dev);
1066         }
1067         ppp_xmit_unlock(ppp);
1068 }
1069
1070 static inline struct sk_buff *
1071 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1072 {
1073         struct sk_buff *new_skb;
1074         int len;
1075         int new_skb_size = ppp->dev->mtu +
1076                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1077         int compressor_skb_size = ppp->dev->mtu +
1078                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1079         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1080         if (!new_skb) {
1081                 if (net_ratelimit())
1082                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1083                 return NULL;
1084         }
1085         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1086                 skb_reserve(new_skb,
1087                             ppp->dev->hard_header_len - PPP_HDRLEN);
1088
1089         /* compressor still expects A/C bytes in hdr */
1090         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1091                                    new_skb->data, skb->len + 2,
1092                                    compressor_skb_size);
1093         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1094                 kfree_skb(skb);
1095                 skb = new_skb;
1096                 skb_put(skb, len);
1097                 skb_pull(skb, 2);       /* pull off A/C bytes */
1098         } else if (len == 0) {
1099                 /* didn't compress, or CCP not up yet */
1100                 kfree_skb(new_skb);
1101                 new_skb = skb;
1102         } else {
1103                 /*
1104                  * (len < 0)
1105                  * MPPE requires that we do not send unencrypted
1106                  * frames.  The compressor will return -1 if we
1107                  * should drop the frame.  We cannot simply test
1108                  * the compress_proto because MPPE and MPPC share
1109                  * the same number.
1110                  */
1111                 if (net_ratelimit())
1112                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1113                 kfree_skb(skb);
1114                 kfree_skb(new_skb);
1115                 new_skb = NULL;
1116         }
1117         return new_skb;
1118 }
1119
1120 /*
1121  * Compress and send a frame.
1122  * The caller should have locked the xmit path,
1123  * and xmit_pending should be 0.
1124  */
1125 static void
1126 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1127 {
1128         int proto = PPP_PROTO(skb);
1129         struct sk_buff *new_skb;
1130         int len;
1131         unsigned char *cp;
1132
1133         if (proto < 0x8000) {
1134 #ifdef CONFIG_PPP_FILTER
1135                 /* check if we should pass this packet */
1136                 /* the filter instructions are constructed assuming
1137                    a four-byte PPP header on each packet */
1138                 *skb_push(skb, 2) = 1;
1139                 if (ppp->pass_filter &&
1140                     sk_run_filter(skb, ppp->pass_filter) == 0) {
1141                         if (ppp->debug & 1)
1142                                 netdev_printk(KERN_DEBUG, ppp->dev,
1143                                               "PPP: outbound frame "
1144                                               "not passed\n");
1145                         kfree_skb(skb);
1146                         return;
1147                 }
1148                 /* if this packet passes the active filter, record the time */
1149                 if (!(ppp->active_filter &&
1150                       sk_run_filter(skb, ppp->active_filter) == 0))
1151                         ppp->last_xmit = jiffies;
1152                 skb_pull(skb, 2);
1153 #else
1154                 /* for data packets, record the time */
1155                 ppp->last_xmit = jiffies;
1156 #endif /* CONFIG_PPP_FILTER */
1157         }
1158
1159         ++ppp->dev->stats.tx_packets;
1160         ppp->dev->stats.tx_bytes += skb->len - 2;
1161
1162         switch (proto) {
1163         case PPP_IP:
1164                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1165                         break;
1166                 /* try to do VJ TCP header compression */
1167                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1168                                     GFP_ATOMIC);
1169                 if (!new_skb) {
1170                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1171                         goto drop;
1172                 }
1173                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1174                 cp = skb->data + 2;
1175                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1176                                     new_skb->data + 2, &cp,
1177                                     !(ppp->flags & SC_NO_TCP_CCID));
1178                 if (cp == skb->data + 2) {
1179                         /* didn't compress */
1180                         kfree_skb(new_skb);
1181                 } else {
1182                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1183                                 proto = PPP_VJC_COMP;
1184                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1185                         } else {
1186                                 proto = PPP_VJC_UNCOMP;
1187                                 cp[0] = skb->data[2];
1188                         }
1189                         kfree_skb(skb);
1190                         skb = new_skb;
1191                         cp = skb_put(skb, len + 2);
1192                         cp[0] = 0;
1193                         cp[1] = proto;
1194                 }
1195                 break;
1196
1197         case PPP_CCP:
1198                 /* peek at outbound CCP frames */
1199                 ppp_ccp_peek(ppp, skb, 0);
1200                 break;
1201         }
1202
1203         /* try to do packet compression */
1204         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1205             proto != PPP_LCP && proto != PPP_CCP) {
1206                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1207                         if (net_ratelimit())
1208                                 netdev_err(ppp->dev,
1209                                            "ppp: compression required but "
1210                                            "down - pkt dropped.\n");
1211                         goto drop;
1212                 }
1213                 skb = pad_compress_skb(ppp, skb);
1214                 if (!skb)
1215                         goto drop;
1216         }
1217
1218         /*
1219          * If we are waiting for traffic (demand dialling),
1220          * queue it up for pppd to receive.
1221          */
1222         if (ppp->flags & SC_LOOP_TRAFFIC) {
1223                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1224                         goto drop;
1225                 skb_queue_tail(&ppp->file.rq, skb);
1226                 wake_up_interruptible(&ppp->file.rwait);
1227                 return;
1228         }
1229
1230         ppp->xmit_pending = skb;
1231         ppp_push(ppp);
1232         return;
1233
1234  drop:
1235         kfree_skb(skb);
1236         ++ppp->dev->stats.tx_errors;
1237 }
1238
1239 /*
1240  * Try to send the frame in xmit_pending.
1241  * The caller should have the xmit path locked.
1242  */
1243 static void
1244 ppp_push(struct ppp *ppp)
1245 {
1246         struct list_head *list;
1247         struct channel *pch;
1248         struct sk_buff *skb = ppp->xmit_pending;
1249
1250         if (!skb)
1251                 return;
1252
1253         list = &ppp->channels;
1254         if (list_empty(list)) {
1255                 /* nowhere to send the packet, just drop it */
1256                 ppp->xmit_pending = NULL;
1257                 kfree_skb(skb);
1258                 return;
1259         }
1260
1261         if ((ppp->flags & SC_MULTILINK) == 0) {
1262                 /* not doing multilink: send it down the first channel */
1263                 list = list->next;
1264                 pch = list_entry(list, struct channel, clist);
1265
1266                 spin_lock_bh(&pch->downl);
1267                 if (pch->chan) {
1268                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1269                                 ppp->xmit_pending = NULL;
1270                 } else {
1271                         /* channel got unregistered */
1272                         kfree_skb(skb);
1273                         ppp->xmit_pending = NULL;
1274                 }
1275                 spin_unlock_bh(&pch->downl);
1276                 return;
1277         }
1278
1279 #ifdef CONFIG_PPP_MULTILINK
1280         /* Multilink: fragment the packet over as many links
1281            as can take the packet at the moment. */
1282         if (!ppp_mp_explode(ppp, skb))
1283                 return;
1284 #endif /* CONFIG_PPP_MULTILINK */
1285
1286         ppp->xmit_pending = NULL;
1287         kfree_skb(skb);
1288 }
1289
1290 #ifdef CONFIG_PPP_MULTILINK
1291 static bool mp_protocol_compress __read_mostly = true;
1292 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1293 MODULE_PARM_DESC(mp_protocol_compress,
1294                  "compress protocol id in multilink fragments");
1295
1296 /*
1297  * Divide a packet to be transmitted into fragments and
1298  * send them out the individual links.
1299  */
1300 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1301 {
1302         int len, totlen;
1303         int i, bits, hdrlen, mtu;
1304         int flen;
1305         int navail, nfree, nzero;
1306         int nbigger;
1307         int totspeed;
1308         int totfree;
1309         unsigned char *p, *q;
1310         struct list_head *list;
1311         struct channel *pch;
1312         struct sk_buff *frag;
1313         struct ppp_channel *chan;
1314
1315         totspeed = 0; /*total bitrate of the bundle*/
1316         nfree = 0; /* # channels which have no packet already queued */
1317         navail = 0; /* total # of usable channels (not deregistered) */
1318         nzero = 0; /* number of channels with zero speed associated*/
1319         totfree = 0; /*total # of channels available and
1320                                   *having no queued packets before
1321                                   *starting the fragmentation*/
1322
1323         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1324         i = 0;
1325         list_for_each_entry(pch, &ppp->channels, clist) {
1326                 if (pch->chan) {
1327                         pch->avail = 1;
1328                         navail++;
1329                         pch->speed = pch->chan->speed;
1330                 } else {
1331                         pch->avail = 0;
1332                 }
1333                 if (pch->avail) {
1334                         if (skb_queue_empty(&pch->file.xq) ||
1335                                 !pch->had_frag) {
1336                                         if (pch->speed == 0)
1337                                                 nzero++;
1338                                         else
1339                                                 totspeed += pch->speed;
1340
1341                                         pch->avail = 2;
1342                                         ++nfree;
1343                                         ++totfree;
1344                                 }
1345                         if (!pch->had_frag && i < ppp->nxchan)
1346                                 ppp->nxchan = i;
1347                 }
1348                 ++i;
1349         }
1350         /*
1351          * Don't start sending this packet unless at least half of
1352          * the channels are free.  This gives much better TCP
1353          * performance if we have a lot of channels.
1354          */
1355         if (nfree == 0 || nfree < navail / 2)
1356                 return 0; /* can't take now, leave it in xmit_pending */
1357
1358         /* Do protocol field compression */
1359         p = skb->data;
1360         len = skb->len;
1361         if (*p == 0 && mp_protocol_compress) {
1362                 ++p;
1363                 --len;
1364         }
1365
1366         totlen = len;
1367         nbigger = len % nfree;
1368
1369         /* skip to the channel after the one we last used
1370            and start at that one */
1371         list = &ppp->channels;
1372         for (i = 0; i < ppp->nxchan; ++i) {
1373                 list = list->next;
1374                 if (list == &ppp->channels) {
1375                         i = 0;
1376                         break;
1377                 }
1378         }
1379
1380         /* create a fragment for each channel */
1381         bits = B;
1382         while (len > 0) {
1383                 list = list->next;
1384                 if (list == &ppp->channels) {
1385                         i = 0;
1386                         continue;
1387                 }
1388                 pch = list_entry(list, struct channel, clist);
1389                 ++i;
1390                 if (!pch->avail)
1391                         continue;
1392
1393                 /*
1394                  * Skip this channel if it has a fragment pending already and
1395                  * we haven't given a fragment to all of the free channels.
1396                  */
1397                 if (pch->avail == 1) {
1398                         if (nfree > 0)
1399                                 continue;
1400                 } else {
1401                         pch->avail = 1;
1402                 }
1403
1404                 /* check the channel's mtu and whether it is still attached. */
1405                 spin_lock_bh(&pch->downl);
1406                 if (pch->chan == NULL) {
1407                         /* can't use this channel, it's being deregistered */
1408                         if (pch->speed == 0)
1409                                 nzero--;
1410                         else
1411                                 totspeed -= pch->speed;
1412
1413                         spin_unlock_bh(&pch->downl);
1414                         pch->avail = 0;
1415                         totlen = len;
1416                         totfree--;
1417                         nfree--;
1418                         if (--navail == 0)
1419                                 break;
1420                         continue;
1421                 }
1422
1423                 /*
1424                 *if the channel speed is not set divide
1425                 *the packet evenly among the free channels;
1426                 *otherwise divide it according to the speed
1427                 *of the channel we are going to transmit on
1428                 */
1429                 flen = len;
1430                 if (nfree > 0) {
1431                         if (pch->speed == 0) {
1432                                 flen = len/nfree;
1433                                 if (nbigger > 0) {
1434                                         flen++;
1435                                         nbigger--;
1436                                 }
1437                         } else {
1438                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1439                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1440                                 if (nbigger > 0) {
1441                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1442                                         nbigger -= ((totfree - nzero)*pch->speed)/
1443                                                         totspeed;
1444                                 }
1445                         }
1446                         nfree--;
1447                 }
1448
1449                 /*
1450                  *check if we are on the last channel or
1451                  *we exceded the length of the data to
1452                  *fragment
1453                  */
1454                 if ((nfree <= 0) || (flen > len))
1455                         flen = len;
1456                 /*
1457                  *it is not worth to tx on slow channels:
1458                  *in that case from the resulting flen according to the
1459                  *above formula will be equal or less than zero.
1460                  *Skip the channel in this case
1461                  */
1462                 if (flen <= 0) {
1463                         pch->avail = 2;
1464                         spin_unlock_bh(&pch->downl);
1465                         continue;
1466                 }
1467
1468                 /*
1469                  * hdrlen includes the 2-byte PPP protocol field, but the
1470                  * MTU counts only the payload excluding the protocol field.
1471                  * (RFC1661 Section 2)
1472                  */
1473                 mtu = pch->chan->mtu - (hdrlen - 2);
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                 put_unaligned_be16(PPP_MP, q);
1487                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1488                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1489                         q[3] = ppp->nxseq;
1490                 } else {
1491                         q[2] = bits;
1492                         q[3] = ppp->nxseq >> 16;
1493                         q[4] = ppp->nxseq >> 8;
1494                         q[5] = ppp->nxseq;
1495                 }
1496
1497                 memcpy(q + hdrlen, p, flen);
1498
1499                 /* try to send it down the channel */
1500                 chan = pch->chan;
1501                 if (!skb_queue_empty(&pch->file.xq) ||
1502                         !chan->ops->start_xmit(chan, frag))
1503                         skb_queue_tail(&pch->file.xq, frag);
1504                 pch->had_frag = 1;
1505                 p += flen;
1506                 len -= flen;
1507                 ++ppp->nxseq;
1508                 bits = 0;
1509                 spin_unlock_bh(&pch->downl);
1510         }
1511         ppp->nxchan = i;
1512
1513         return 1;
1514
1515  noskb:
1516         spin_unlock_bh(&pch->downl);
1517         if (ppp->debug & 1)
1518                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1519         ++ppp->dev->stats.tx_errors;
1520         ++ppp->nxseq;
1521         return 1;       /* abandon the frame */
1522 }
1523 #endif /* CONFIG_PPP_MULTILINK */
1524
1525 /*
1526  * Try to send data out on a channel.
1527  */
1528 static void
1529 ppp_channel_push(struct channel *pch)
1530 {
1531         struct sk_buff *skb;
1532         struct ppp *ppp;
1533
1534         spin_lock_bh(&pch->downl);
1535         if (pch->chan) {
1536                 while (!skb_queue_empty(&pch->file.xq)) {
1537                         skb = skb_dequeue(&pch->file.xq);
1538                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1539                                 /* put the packet back and try again later */
1540                                 skb_queue_head(&pch->file.xq, skb);
1541                                 break;
1542                         }
1543                 }
1544         } else {
1545                 /* channel got deregistered */
1546                 skb_queue_purge(&pch->file.xq);
1547         }
1548         spin_unlock_bh(&pch->downl);
1549         /* see if there is anything from the attached unit to be sent */
1550         if (skb_queue_empty(&pch->file.xq)) {
1551                 read_lock_bh(&pch->upl);
1552                 ppp = pch->ppp;
1553                 if (ppp)
1554                         ppp_xmit_process(ppp);
1555                 read_unlock_bh(&pch->upl);
1556         }
1557 }
1558
1559 /*
1560  * Receive-side routines.
1561  */
1562
1563 struct ppp_mp_skb_parm {
1564         u32             sequence;
1565         u8              BEbits;
1566 };
1567 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1568
1569 static inline void
1570 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1571 {
1572         ppp_recv_lock(ppp);
1573         if (!ppp->closing)
1574                 ppp_receive_frame(ppp, skb, pch);
1575         else
1576                 kfree_skb(skb);
1577         ppp_recv_unlock(ppp);
1578 }
1579
1580 void
1581 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1582 {
1583         struct channel *pch = chan->ppp;
1584         int proto;
1585
1586         if (!pch) {
1587                 kfree_skb(skb);
1588                 return;
1589         }
1590
1591         read_lock_bh(&pch->upl);
1592         if (!pskb_may_pull(skb, 2)) {
1593                 kfree_skb(skb);
1594                 if (pch->ppp) {
1595                         ++pch->ppp->dev->stats.rx_length_errors;
1596                         ppp_receive_error(pch->ppp);
1597                 }
1598                 goto done;
1599         }
1600
1601         proto = PPP_PROTO(skb);
1602         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1603                 /* put it on the channel queue */
1604                 skb_queue_tail(&pch->file.rq, skb);
1605                 /* drop old frames if queue too long */
1606                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1607                        (skb = skb_dequeue(&pch->file.rq)))
1608                         kfree_skb(skb);
1609                 wake_up_interruptible(&pch->file.rwait);
1610         } else {
1611                 ppp_do_recv(pch->ppp, skb, pch);
1612         }
1613
1614 done:
1615         read_unlock_bh(&pch->upl);
1616 }
1617
1618 /* Put a 0-length skb in the receive queue as an error indication */
1619 void
1620 ppp_input_error(struct ppp_channel *chan, int code)
1621 {
1622         struct channel *pch = chan->ppp;
1623         struct sk_buff *skb;
1624
1625         if (!pch)
1626                 return;
1627
1628         read_lock_bh(&pch->upl);
1629         if (pch->ppp) {
1630                 skb = alloc_skb(0, GFP_ATOMIC);
1631                 if (skb) {
1632                         skb->len = 0;           /* probably unnecessary */
1633                         skb->cb[0] = code;
1634                         ppp_do_recv(pch->ppp, skb, pch);
1635                 }
1636         }
1637         read_unlock_bh(&pch->upl);
1638 }
1639
1640 /*
1641  * We come in here to process a received frame.
1642  * The receive side of the ppp unit is locked.
1643  */
1644 static void
1645 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1646 {
1647         /* note: a 0-length skb is used as an error indication */
1648         if (skb->len > 0) {
1649 #ifdef CONFIG_PPP_MULTILINK
1650                 /* XXX do channel-level decompression here */
1651                 if (PPP_PROTO(skb) == PPP_MP)
1652                         ppp_receive_mp_frame(ppp, skb, pch);
1653                 else
1654 #endif /* CONFIG_PPP_MULTILINK */
1655                         ppp_receive_nonmp_frame(ppp, skb);
1656         } else {
1657                 kfree_skb(skb);
1658                 ppp_receive_error(ppp);
1659         }
1660 }
1661
1662 static void
1663 ppp_receive_error(struct ppp *ppp)
1664 {
1665         ++ppp->dev->stats.rx_errors;
1666         if (ppp->vj)
1667                 slhc_toss(ppp->vj);
1668 }
1669
1670 static void
1671 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1672 {
1673         struct sk_buff *ns;
1674         int proto, len, npi;
1675
1676         /*
1677          * Decompress the frame, if compressed.
1678          * Note that some decompressors need to see uncompressed frames
1679          * that come in as well as compressed frames.
1680          */
1681         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1682             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1683                 skb = ppp_decompress_frame(ppp, skb);
1684
1685         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1686                 goto err;
1687
1688         proto = PPP_PROTO(skb);
1689         switch (proto) {
1690         case PPP_VJC_COMP:
1691                 /* decompress VJ compressed packets */
1692                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1693                         goto err;
1694
1695                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1696                         /* copy to a new sk_buff with more tailroom */
1697                         ns = dev_alloc_skb(skb->len + 128);
1698                         if (!ns) {
1699                                 netdev_err(ppp->dev, "PPP: no memory "
1700                                            "(VJ decomp)\n");
1701                                 goto err;
1702                         }
1703                         skb_reserve(ns, 2);
1704                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1705                         kfree_skb(skb);
1706                         skb = ns;
1707                 }
1708                 else
1709                         skb->ip_summed = CHECKSUM_NONE;
1710
1711                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1712                 if (len <= 0) {
1713                         netdev_printk(KERN_DEBUG, ppp->dev,
1714                                       "PPP: VJ decompression error\n");
1715                         goto err;
1716                 }
1717                 len += 2;
1718                 if (len > skb->len)
1719                         skb_put(skb, len - skb->len);
1720                 else if (len < skb->len)
1721                         skb_trim(skb, len);
1722                 proto = PPP_IP;
1723                 break;
1724
1725         case PPP_VJC_UNCOMP:
1726                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1727                         goto err;
1728
1729                 /* Until we fix the decompressor need to make sure
1730                  * data portion is linear.
1731                  */
1732                 if (!pskb_may_pull(skb, skb->len))
1733                         goto err;
1734
1735                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1736                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1737                         goto err;
1738                 }
1739                 proto = PPP_IP;
1740                 break;
1741
1742         case PPP_CCP:
1743                 ppp_ccp_peek(ppp, skb, 1);
1744                 break;
1745         }
1746
1747         ++ppp->dev->stats.rx_packets;
1748         ppp->dev->stats.rx_bytes += skb->len - 2;
1749
1750         npi = proto_to_npindex(proto);
1751         if (npi < 0) {
1752                 /* control or unknown frame - pass it to pppd */
1753                 skb_queue_tail(&ppp->file.rq, skb);
1754                 /* limit queue length by dropping old frames */
1755                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1756                        (skb = skb_dequeue(&ppp->file.rq)))
1757                         kfree_skb(skb);
1758                 /* wake up any process polling or blocking on read */
1759                 wake_up_interruptible(&ppp->file.rwait);
1760
1761         } else {
1762                 /* network protocol frame - give it to the kernel */
1763
1764 #ifdef CONFIG_PPP_FILTER
1765                 /* check if the packet passes the pass and active filters */
1766                 /* the filter instructions are constructed assuming
1767                    a four-byte PPP header on each packet */
1768                 if (ppp->pass_filter || ppp->active_filter) {
1769                         if (skb_cloned(skb) &&
1770                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1771                                 goto err;
1772
1773                         *skb_push(skb, 2) = 0;
1774                         if (ppp->pass_filter &&
1775                             sk_run_filter(skb, ppp->pass_filter) == 0) {
1776                                 if (ppp->debug & 1)
1777                                         netdev_printk(KERN_DEBUG, ppp->dev,
1778                                                       "PPP: inbound frame "
1779                                                       "not passed\n");
1780                                 kfree_skb(skb);
1781                                 return;
1782                         }
1783                         if (!(ppp->active_filter &&
1784                               sk_run_filter(skb, ppp->active_filter) == 0))
1785                                 ppp->last_recv = jiffies;
1786                         __skb_pull(skb, 2);
1787                 } else
1788 #endif /* CONFIG_PPP_FILTER */
1789                         ppp->last_recv = jiffies;
1790
1791                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1792                     ppp->npmode[npi] != NPMODE_PASS) {
1793                         kfree_skb(skb);
1794                 } else {
1795                         /* chop off protocol */
1796                         skb_pull_rcsum(skb, 2);
1797                         skb->dev = ppp->dev;
1798                         skb->protocol = htons(npindex_to_ethertype[npi]);
1799                         skb_reset_mac_header(skb);
1800                         netif_rx(skb);
1801                 }
1802         }
1803         return;
1804
1805  err:
1806         kfree_skb(skb);
1807         ppp_receive_error(ppp);
1808 }
1809
1810 static struct sk_buff *
1811 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1812 {
1813         int proto = PPP_PROTO(skb);
1814         struct sk_buff *ns;
1815         int len;
1816
1817         /* Until we fix all the decompressor's need to make sure
1818          * data portion is linear.
1819          */
1820         if (!pskb_may_pull(skb, skb->len))
1821                 goto err;
1822
1823         if (proto == PPP_COMP) {
1824                 int obuff_size;
1825
1826                 switch(ppp->rcomp->compress_proto) {
1827                 case CI_MPPE:
1828                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1829                         break;
1830                 default:
1831                         obuff_size = ppp->mru + PPP_HDRLEN;
1832                         break;
1833                 }
1834
1835                 ns = dev_alloc_skb(obuff_size);
1836                 if (!ns) {
1837                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1838                                    "no memory\n");
1839                         goto err;
1840                 }
1841                 /* the decompressor still expects the A/C bytes in the hdr */
1842                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1843                                 skb->len + 2, ns->data, obuff_size);
1844                 if (len < 0) {
1845                         /* Pass the compressed frame to pppd as an
1846                            error indication. */
1847                         if (len == DECOMP_FATALERROR)
1848                                 ppp->rstate |= SC_DC_FERROR;
1849                         kfree_skb(ns);
1850                         goto err;
1851                 }
1852
1853                 kfree_skb(skb);
1854                 skb = ns;
1855                 skb_put(skb, len);
1856                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1857
1858         } else {
1859                 /* Uncompressed frame - pass to decompressor so it
1860                    can update its dictionary if necessary. */
1861                 if (ppp->rcomp->incomp)
1862                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1863                                            skb->len + 2);
1864         }
1865
1866         return skb;
1867
1868  err:
1869         ppp->rstate |= SC_DC_ERROR;
1870         ppp_receive_error(ppp);
1871         return skb;
1872 }
1873
1874 #ifdef CONFIG_PPP_MULTILINK
1875 /*
1876  * Receive a multilink frame.
1877  * We put it on the reconstruction queue and then pull off
1878  * as many completed frames as we can.
1879  */
1880 static void
1881 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1882 {
1883         u32 mask, seq;
1884         struct channel *ch;
1885         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1886
1887         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1888                 goto err;               /* no good, throw it away */
1889
1890         /* Decode sequence number and begin/end bits */
1891         if (ppp->flags & SC_MP_SHORTSEQ) {
1892                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1893                 mask = 0xfff;
1894         } else {
1895                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1896                 mask = 0xffffff;
1897         }
1898         PPP_MP_CB(skb)->BEbits = skb->data[2];
1899         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1900
1901         /*
1902          * Do protocol ID decompression on the first fragment of each packet.
1903          */
1904         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
1905                 *skb_push(skb, 1) = 0;
1906
1907         /*
1908          * Expand sequence number to 32 bits, making it as close
1909          * as possible to ppp->minseq.
1910          */
1911         seq |= ppp->minseq & ~mask;
1912         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1913                 seq += mask + 1;
1914         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1915                 seq -= mask + 1;        /* should never happen */
1916         PPP_MP_CB(skb)->sequence = seq;
1917         pch->lastseq = seq;
1918
1919         /*
1920          * If this packet comes before the next one we were expecting,
1921          * drop it.
1922          */
1923         if (seq_before(seq, ppp->nextseq)) {
1924                 kfree_skb(skb);
1925                 ++ppp->dev->stats.rx_dropped;
1926                 ppp_receive_error(ppp);
1927                 return;
1928         }
1929
1930         /*
1931          * Reevaluate minseq, the minimum over all channels of the
1932          * last sequence number received on each channel.  Because of
1933          * the increasing sequence number rule, we know that any fragment
1934          * before `minseq' which hasn't arrived is never going to arrive.
1935          * The list of channels can't change because we have the receive
1936          * side of the ppp unit locked.
1937          */
1938         list_for_each_entry(ch, &ppp->channels, clist) {
1939                 if (seq_before(ch->lastseq, seq))
1940                         seq = ch->lastseq;
1941         }
1942         if (seq_before(ppp->minseq, seq))
1943                 ppp->minseq = seq;
1944
1945         /* Put the fragment on the reconstruction queue */
1946         ppp_mp_insert(ppp, skb);
1947
1948         /* If the queue is getting long, don't wait any longer for packets
1949            before the start of the queue. */
1950         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1951                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
1952                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
1953                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
1954         }
1955
1956         /* Pull completed packets off the queue and receive them. */
1957         while ((skb = ppp_mp_reconstruct(ppp))) {
1958                 if (pskb_may_pull(skb, 2))
1959                         ppp_receive_nonmp_frame(ppp, skb);
1960                 else {
1961                         ++ppp->dev->stats.rx_length_errors;
1962                         kfree_skb(skb);
1963                         ppp_receive_error(ppp);
1964                 }
1965         }
1966
1967         return;
1968
1969  err:
1970         kfree_skb(skb);
1971         ppp_receive_error(ppp);
1972 }
1973
1974 /*
1975  * Insert a fragment on the MP reconstruction queue.
1976  * The queue is ordered by increasing sequence number.
1977  */
1978 static void
1979 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1980 {
1981         struct sk_buff *p;
1982         struct sk_buff_head *list = &ppp->mrq;
1983         u32 seq = PPP_MP_CB(skb)->sequence;
1984
1985         /* N.B. we don't need to lock the list lock because we have the
1986            ppp unit receive-side lock. */
1987         skb_queue_walk(list, p) {
1988                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
1989                         break;
1990         }
1991         __skb_queue_before(list, p, skb);
1992 }
1993
1994 /*
1995  * Reconstruct a packet from the MP fragment queue.
1996  * We go through increasing sequence numbers until we find a
1997  * complete packet, or we get to the sequence number for a fragment
1998  * which hasn't arrived but might still do so.
1999  */
2000 static struct sk_buff *
2001 ppp_mp_reconstruct(struct ppp *ppp)
2002 {
2003         u32 seq = ppp->nextseq;
2004         u32 minseq = ppp->minseq;
2005         struct sk_buff_head *list = &ppp->mrq;
2006         struct sk_buff *p, *tmp;
2007         struct sk_buff *head, *tail;
2008         struct sk_buff *skb = NULL;
2009         int lost = 0, len = 0;
2010
2011         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2012                 return NULL;
2013         head = list->next;
2014         tail = NULL;
2015         skb_queue_walk_safe(list, p, tmp) {
2016         again:
2017                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2018                         /* this can't happen, anyway ignore the skb */
2019                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2020                                    "seq %u < %u\n",
2021                                    PPP_MP_CB(p)->sequence, seq);
2022                         __skb_unlink(p, list);
2023                         kfree_skb(p);
2024                         continue;
2025                 }
2026                 if (PPP_MP_CB(p)->sequence != seq) {
2027                         u32 oldseq;
2028                         /* Fragment `seq' is missing.  If it is after
2029                            minseq, it might arrive later, so stop here. */
2030                         if (seq_after(seq, minseq))
2031                                 break;
2032                         /* Fragment `seq' is lost, keep going. */
2033                         lost = 1;
2034                         oldseq = seq;
2035                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2036                                 minseq + 1: PPP_MP_CB(p)->sequence;
2037
2038                         if (ppp->debug & 1)
2039                                 netdev_printk(KERN_DEBUG, ppp->dev,
2040                                               "lost frag %u..%u\n",
2041                                               oldseq, seq-1);
2042
2043                         goto again;
2044                 }
2045
2046                 /*
2047                  * At this point we know that all the fragments from
2048                  * ppp->nextseq to seq are either present or lost.
2049                  * Also, there are no complete packets in the queue
2050                  * that have no missing fragments and end before this
2051                  * fragment.
2052                  */
2053
2054                 /* B bit set indicates this fragment starts a packet */
2055                 if (PPP_MP_CB(p)->BEbits & B) {
2056                         head = p;
2057                         lost = 0;
2058                         len = 0;
2059                 }
2060
2061                 len += p->len;
2062
2063                 /* Got a complete packet yet? */
2064                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2065                     (PPP_MP_CB(head)->BEbits & B)) {
2066                         if (len > ppp->mrru + 2) {
2067                                 ++ppp->dev->stats.rx_length_errors;
2068                                 netdev_printk(KERN_DEBUG, ppp->dev,
2069                                               "PPP: reconstructed packet"
2070                                               " is too long (%d)\n", len);
2071                         } else {
2072                                 tail = p;
2073                                 break;
2074                         }
2075                         ppp->nextseq = seq + 1;
2076                 }
2077
2078                 /*
2079                  * If this is the ending fragment of a packet,
2080                  * and we haven't found a complete valid packet yet,
2081                  * we can discard up to and including this fragment.
2082                  */
2083                 if (PPP_MP_CB(p)->BEbits & E) {
2084                         struct sk_buff *tmp2;
2085
2086                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2087                                 if (ppp->debug & 1)
2088                                         netdev_printk(KERN_DEBUG, ppp->dev,
2089                                                       "discarding frag %u\n",
2090                                                       PPP_MP_CB(p)->sequence);
2091                                 __skb_unlink(p, list);
2092                                 kfree_skb(p);
2093                         }
2094                         head = skb_peek(list);
2095                         if (!head)
2096                                 break;
2097                 }
2098                 ++seq;
2099         }
2100
2101         /* If we have a complete packet, copy it all into one skb. */
2102         if (tail != NULL) {
2103                 /* If we have discarded any fragments,
2104                    signal a receive error. */
2105                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2106                         skb_queue_walk_safe(list, p, tmp) {
2107                                 if (p == head)
2108                                         break;
2109                                 if (ppp->debug & 1)
2110                                         netdev_printk(KERN_DEBUG, ppp->dev,
2111                                                       "discarding frag %u\n",
2112                                                       PPP_MP_CB(p)->sequence);
2113                                 __skb_unlink(p, list);
2114                                 kfree_skb(p);
2115                         }
2116
2117                         if (ppp->debug & 1)
2118                                 netdev_printk(KERN_DEBUG, ppp->dev,
2119                                               "  missed pkts %u..%u\n",
2120                                               ppp->nextseq,
2121                                               PPP_MP_CB(head)->sequence-1);
2122                         ++ppp->dev->stats.rx_dropped;
2123                         ppp_receive_error(ppp);
2124                 }
2125
2126                 skb = head;
2127                 if (head != tail) {
2128                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2129                         p = skb_queue_next(list, head);
2130                         __skb_unlink(skb, list);
2131                         skb_queue_walk_from_safe(list, p, tmp) {
2132                                 __skb_unlink(p, list);
2133                                 *fragpp = p;
2134                                 p->next = NULL;
2135                                 fragpp = &p->next;
2136
2137                                 skb->len += p->len;
2138                                 skb->data_len += p->len;
2139                                 skb->truesize += p->truesize;
2140
2141                                 if (p == tail)
2142                                         break;
2143                         }
2144                 } else {
2145                         __skb_unlink(skb, list);
2146                 }
2147
2148                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2149         }
2150
2151         return skb;
2152 }
2153 #endif /* CONFIG_PPP_MULTILINK */
2154
2155 /*
2156  * Channel interface.
2157  */
2158
2159 /* Create a new, unattached ppp channel. */
2160 int ppp_register_channel(struct ppp_channel *chan)
2161 {
2162         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2163 }
2164
2165 /* Create a new, unattached ppp channel for specified net. */
2166 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2167 {
2168         struct channel *pch;
2169         struct ppp_net *pn;
2170
2171         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2172         if (!pch)
2173                 return -ENOMEM;
2174
2175         pn = ppp_pernet(net);
2176
2177         pch->ppp = NULL;
2178         pch->chan = chan;
2179         pch->chan_net = net;
2180         chan->ppp = pch;
2181         init_ppp_file(&pch->file, CHANNEL);
2182         pch->file.hdrlen = chan->hdrlen;
2183 #ifdef CONFIG_PPP_MULTILINK
2184         pch->lastseq = -1;
2185 #endif /* CONFIG_PPP_MULTILINK */
2186         init_rwsem(&pch->chan_sem);
2187         spin_lock_init(&pch->downl);
2188         rwlock_init(&pch->upl);
2189
2190         spin_lock_bh(&pn->all_channels_lock);
2191         pch->file.index = ++pn->last_channel_index;
2192         list_add(&pch->list, &pn->new_channels);
2193         atomic_inc(&channel_count);
2194         spin_unlock_bh(&pn->all_channels_lock);
2195
2196         return 0;
2197 }
2198
2199 /*
2200  * Return the index of a channel.
2201  */
2202 int ppp_channel_index(struct ppp_channel *chan)
2203 {
2204         struct channel *pch = chan->ppp;
2205
2206         if (pch)
2207                 return pch->file.index;
2208         return -1;
2209 }
2210
2211 /*
2212  * Return the PPP unit number to which a channel is connected.
2213  */
2214 int ppp_unit_number(struct ppp_channel *chan)
2215 {
2216         struct channel *pch = chan->ppp;
2217         int unit = -1;
2218
2219         if (pch) {
2220                 read_lock_bh(&pch->upl);
2221                 if (pch->ppp)
2222                         unit = pch->ppp->file.index;
2223                 read_unlock_bh(&pch->upl);
2224         }
2225         return unit;
2226 }
2227
2228 /*
2229  * Return the PPP device interface name of a channel.
2230  */
2231 char *ppp_dev_name(struct ppp_channel *chan)
2232 {
2233         struct channel *pch = chan->ppp;
2234         char *name = NULL;
2235
2236         if (pch) {
2237                 read_lock_bh(&pch->upl);
2238                 if (pch->ppp && pch->ppp->dev)
2239                         name = pch->ppp->dev->name;
2240                 read_unlock_bh(&pch->upl);
2241         }
2242         return name;
2243 }
2244
2245
2246 /*
2247  * Disconnect a channel from the generic layer.
2248  * This must be called in process context.
2249  */
2250 void
2251 ppp_unregister_channel(struct ppp_channel *chan)
2252 {
2253         struct channel *pch = chan->ppp;
2254         struct ppp_net *pn;
2255
2256         if (!pch)
2257                 return;         /* should never happen */
2258
2259         chan->ppp = NULL;
2260
2261         /*
2262          * This ensures that we have returned from any calls into the
2263          * the channel's start_xmit or ioctl routine before we proceed.
2264          */
2265         down_write(&pch->chan_sem);
2266         spin_lock_bh(&pch->downl);
2267         pch->chan = NULL;
2268         spin_unlock_bh(&pch->downl);
2269         up_write(&pch->chan_sem);
2270         ppp_disconnect_channel(pch);
2271
2272         pn = ppp_pernet(pch->chan_net);
2273         spin_lock_bh(&pn->all_channels_lock);
2274         list_del(&pch->list);
2275         spin_unlock_bh(&pn->all_channels_lock);
2276
2277         pch->file.dead = 1;
2278         wake_up_interruptible(&pch->file.rwait);
2279         if (atomic_dec_and_test(&pch->file.refcnt))
2280                 ppp_destroy_channel(pch);
2281 }
2282
2283 /*
2284  * Callback from a channel when it can accept more to transmit.
2285  * This should be called at BH/softirq level, not interrupt level.
2286  */
2287 void
2288 ppp_output_wakeup(struct ppp_channel *chan)
2289 {
2290         struct channel *pch = chan->ppp;
2291
2292         if (!pch)
2293                 return;
2294         ppp_channel_push(pch);
2295 }
2296
2297 /*
2298  * Compression control.
2299  */
2300
2301 /* Process the PPPIOCSCOMPRESS ioctl. */
2302 static int
2303 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2304 {
2305         int err;
2306         struct compressor *cp, *ocomp;
2307         struct ppp_option_data data;
2308         void *state, *ostate;
2309         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2310
2311         err = -EFAULT;
2312         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2313             (data.length <= CCP_MAX_OPTION_LENGTH &&
2314              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2315                 goto out;
2316         err = -EINVAL;
2317         if (data.length > CCP_MAX_OPTION_LENGTH ||
2318             ccp_option[1] < 2 || ccp_option[1] > data.length)
2319                 goto out;
2320
2321         cp = try_then_request_module(
2322                 find_compressor(ccp_option[0]),
2323                 "ppp-compress-%d", ccp_option[0]);
2324         if (!cp)
2325                 goto out;
2326
2327         err = -ENOBUFS;
2328         if (data.transmit) {
2329                 state = cp->comp_alloc(ccp_option, data.length);
2330                 if (state) {
2331                         ppp_xmit_lock(ppp);
2332                         ppp->xstate &= ~SC_COMP_RUN;
2333                         ocomp = ppp->xcomp;
2334                         ostate = ppp->xc_state;
2335                         ppp->xcomp = cp;
2336                         ppp->xc_state = state;
2337                         ppp_xmit_unlock(ppp);
2338                         if (ostate) {
2339                                 ocomp->comp_free(ostate);
2340                                 module_put(ocomp->owner);
2341                         }
2342                         err = 0;
2343                 } else
2344                         module_put(cp->owner);
2345
2346         } else {
2347                 state = cp->decomp_alloc(ccp_option, data.length);
2348                 if (state) {
2349                         ppp_recv_lock(ppp);
2350                         ppp->rstate &= ~SC_DECOMP_RUN;
2351                         ocomp = ppp->rcomp;
2352                         ostate = ppp->rc_state;
2353                         ppp->rcomp = cp;
2354                         ppp->rc_state = state;
2355                         ppp_recv_unlock(ppp);
2356                         if (ostate) {
2357                                 ocomp->decomp_free(ostate);
2358                                 module_put(ocomp->owner);
2359                         }
2360                         err = 0;
2361                 } else
2362                         module_put(cp->owner);
2363         }
2364
2365  out:
2366         return err;
2367 }
2368
2369 /*
2370  * Look at a CCP packet and update our state accordingly.
2371  * We assume the caller has the xmit or recv path locked.
2372  */
2373 static void
2374 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2375 {
2376         unsigned char *dp;
2377         int len;
2378
2379         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2380                 return; /* no header */
2381         dp = skb->data + 2;
2382
2383         switch (CCP_CODE(dp)) {
2384         case CCP_CONFREQ:
2385
2386                 /* A ConfReq starts negotiation of compression
2387                  * in one direction of transmission,
2388                  * and hence brings it down...but which way?
2389                  *
2390                  * Remember:
2391                  * A ConfReq indicates what the sender would like to receive
2392                  */
2393                 if(inbound)
2394                         /* He is proposing what I should send */
2395                         ppp->xstate &= ~SC_COMP_RUN;
2396                 else
2397                         /* I am proposing to what he should send */
2398                         ppp->rstate &= ~SC_DECOMP_RUN;
2399
2400                 break;
2401
2402         case CCP_TERMREQ:
2403         case CCP_TERMACK:
2404                 /*
2405                  * CCP is going down, both directions of transmission
2406                  */
2407                 ppp->rstate &= ~SC_DECOMP_RUN;
2408                 ppp->xstate &= ~SC_COMP_RUN;
2409                 break;
2410
2411         case CCP_CONFACK:
2412                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2413                         break;
2414                 len = CCP_LENGTH(dp);
2415                 if (!pskb_may_pull(skb, len + 2))
2416                         return;         /* too short */
2417                 dp += CCP_HDRLEN;
2418                 len -= CCP_HDRLEN;
2419                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2420                         break;
2421                 if (inbound) {
2422                         /* we will start receiving compressed packets */
2423                         if (!ppp->rc_state)
2424                                 break;
2425                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2426                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2427                                 ppp->rstate |= SC_DECOMP_RUN;
2428                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2429                         }
2430                 } else {
2431                         /* we will soon start sending compressed packets */
2432                         if (!ppp->xc_state)
2433                                 break;
2434                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2435                                         ppp->file.index, 0, ppp->debug))
2436                                 ppp->xstate |= SC_COMP_RUN;
2437                 }
2438                 break;
2439
2440         case CCP_RESETACK:
2441                 /* reset the [de]compressor */
2442                 if ((ppp->flags & SC_CCP_UP) == 0)
2443                         break;
2444                 if (inbound) {
2445                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2446                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2447                                 ppp->rstate &= ~SC_DC_ERROR;
2448                         }
2449                 } else {
2450                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2451                                 ppp->xcomp->comp_reset(ppp->xc_state);
2452                 }
2453                 break;
2454         }
2455 }
2456
2457 /* Free up compression resources. */
2458 static void
2459 ppp_ccp_closed(struct ppp *ppp)
2460 {
2461         void *xstate, *rstate;
2462         struct compressor *xcomp, *rcomp;
2463
2464         ppp_lock(ppp);
2465         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2466         ppp->xstate = 0;
2467         xcomp = ppp->xcomp;
2468         xstate = ppp->xc_state;
2469         ppp->xc_state = NULL;
2470         ppp->rstate = 0;
2471         rcomp = ppp->rcomp;
2472         rstate = ppp->rc_state;
2473         ppp->rc_state = NULL;
2474         ppp_unlock(ppp);
2475
2476         if (xstate) {
2477                 xcomp->comp_free(xstate);
2478                 module_put(xcomp->owner);
2479         }
2480         if (rstate) {
2481                 rcomp->decomp_free(rstate);
2482                 module_put(rcomp->owner);
2483         }
2484 }
2485
2486 /* List of compressors. */
2487 static LIST_HEAD(compressor_list);
2488 static DEFINE_SPINLOCK(compressor_list_lock);
2489
2490 struct compressor_entry {
2491         struct list_head list;
2492         struct compressor *comp;
2493 };
2494
2495 static struct compressor_entry *
2496 find_comp_entry(int proto)
2497 {
2498         struct compressor_entry *ce;
2499
2500         list_for_each_entry(ce, &compressor_list, list) {
2501                 if (ce->comp->compress_proto == proto)
2502                         return ce;
2503         }
2504         return NULL;
2505 }
2506
2507 /* Register a compressor */
2508 int
2509 ppp_register_compressor(struct compressor *cp)
2510 {
2511         struct compressor_entry *ce;
2512         int ret;
2513         spin_lock(&compressor_list_lock);
2514         ret = -EEXIST;
2515         if (find_comp_entry(cp->compress_proto))
2516                 goto out;
2517         ret = -ENOMEM;
2518         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2519         if (!ce)
2520                 goto out;
2521         ret = 0;
2522         ce->comp = cp;
2523         list_add(&ce->list, &compressor_list);
2524  out:
2525         spin_unlock(&compressor_list_lock);
2526         return ret;
2527 }
2528
2529 /* Unregister a compressor */
2530 void
2531 ppp_unregister_compressor(struct compressor *cp)
2532 {
2533         struct compressor_entry *ce;
2534
2535         spin_lock(&compressor_list_lock);
2536         ce = find_comp_entry(cp->compress_proto);
2537         if (ce && ce->comp == cp) {
2538                 list_del(&ce->list);
2539                 kfree(ce);
2540         }
2541         spin_unlock(&compressor_list_lock);
2542 }
2543
2544 /* Find a compressor. */
2545 static struct compressor *
2546 find_compressor(int type)
2547 {
2548         struct compressor_entry *ce;
2549         struct compressor *cp = NULL;
2550
2551         spin_lock(&compressor_list_lock);
2552         ce = find_comp_entry(type);
2553         if (ce) {
2554                 cp = ce->comp;
2555                 if (!try_module_get(cp->owner))
2556                         cp = NULL;
2557         }
2558         spin_unlock(&compressor_list_lock);
2559         return cp;
2560 }
2561
2562 /*
2563  * Miscelleneous stuff.
2564  */
2565
2566 static void
2567 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2568 {
2569         struct slcompress *vj = ppp->vj;
2570
2571         memset(st, 0, sizeof(*st));
2572         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2573         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2574         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2575         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2576         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2577         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2578         if (!vj)
2579                 return;
2580         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2581         st->vj.vjs_compressed = vj->sls_o_compressed;
2582         st->vj.vjs_searches = vj->sls_o_searches;
2583         st->vj.vjs_misses = vj->sls_o_misses;
2584         st->vj.vjs_errorin = vj->sls_i_error;
2585         st->vj.vjs_tossed = vj->sls_i_tossed;
2586         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2587         st->vj.vjs_compressedin = vj->sls_i_compressed;
2588 }
2589
2590 /*
2591  * Stuff for handling the lists of ppp units and channels
2592  * and for initialization.
2593  */
2594
2595 /*
2596  * Create a new ppp interface unit.  Fails if it can't allocate memory
2597  * or if there is already a unit with the requested number.
2598  * unit == -1 means allocate a new number.
2599  */
2600 static struct ppp *
2601 ppp_create_interface(struct net *net, int unit, int *retp)
2602 {
2603         struct ppp *ppp;
2604         struct ppp_net *pn;
2605         struct net_device *dev = NULL;
2606         int ret = -ENOMEM;
2607         int i;
2608
2609         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2610         if (!dev)
2611                 goto out1;
2612
2613         pn = ppp_pernet(net);
2614
2615         ppp = netdev_priv(dev);
2616         ppp->dev = dev;
2617         ppp->mru = PPP_MRU;
2618         init_ppp_file(&ppp->file, INTERFACE);
2619         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2620         for (i = 0; i < NUM_NP; ++i)
2621                 ppp->npmode[i] = NPMODE_PASS;
2622         INIT_LIST_HEAD(&ppp->channels);
2623         spin_lock_init(&ppp->rlock);
2624         spin_lock_init(&ppp->wlock);
2625 #ifdef CONFIG_PPP_MULTILINK
2626         ppp->minseq = -1;
2627         skb_queue_head_init(&ppp->mrq);
2628 #endif /* CONFIG_PPP_MULTILINK */
2629
2630         /*
2631          * drum roll: don't forget to set
2632          * the net device is belong to
2633          */
2634         dev_net_set(dev, net);
2635
2636         mutex_lock(&pn->all_ppp_mutex);
2637
2638         if (unit < 0) {
2639                 unit = unit_get(&pn->units_idr, ppp);
2640                 if (unit < 0) {
2641                         ret = unit;
2642                         goto out2;
2643                 }
2644         } else {
2645                 ret = -EEXIST;
2646                 if (unit_find(&pn->units_idr, unit))
2647                         goto out2; /* unit already exists */
2648                 /*
2649                  * if caller need a specified unit number
2650                  * lets try to satisfy him, otherwise --
2651                  * he should better ask us for new unit number
2652                  *
2653                  * NOTE: yes I know that returning EEXIST it's not
2654                  * fair but at least pppd will ask us to allocate
2655                  * new unit in this case so user is happy :)
2656                  */
2657                 unit = unit_set(&pn->units_idr, ppp, unit);
2658                 if (unit < 0)
2659                         goto out2;
2660         }
2661
2662         /* Initialize the new ppp unit */
2663         ppp->file.index = unit;
2664         sprintf(dev->name, "ppp%d", unit);
2665
2666         ret = register_netdev(dev);
2667         if (ret != 0) {
2668                 unit_put(&pn->units_idr, unit);
2669                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2670                            dev->name, ret);
2671                 goto out2;
2672         }
2673
2674         ppp->ppp_net = net;
2675
2676         atomic_inc(&ppp_unit_count);
2677         mutex_unlock(&pn->all_ppp_mutex);
2678
2679         *retp = 0;
2680         return ppp;
2681
2682 out2:
2683         mutex_unlock(&pn->all_ppp_mutex);
2684         free_netdev(dev);
2685 out1:
2686         *retp = ret;
2687         return NULL;
2688 }
2689
2690 /*
2691  * Initialize a ppp_file structure.
2692  */
2693 static void
2694 init_ppp_file(struct ppp_file *pf, int kind)
2695 {
2696         pf->kind = kind;
2697         skb_queue_head_init(&pf->xq);
2698         skb_queue_head_init(&pf->rq);
2699         atomic_set(&pf->refcnt, 1);
2700         init_waitqueue_head(&pf->rwait);
2701 }
2702
2703 /*
2704  * Take down a ppp interface unit - called when the owning file
2705  * (the one that created the unit) is closed or detached.
2706  */
2707 static void ppp_shutdown_interface(struct ppp *ppp)
2708 {
2709         struct ppp_net *pn;
2710
2711         pn = ppp_pernet(ppp->ppp_net);
2712         mutex_lock(&pn->all_ppp_mutex);
2713
2714         /* This will call dev_close() for us. */
2715         ppp_lock(ppp);
2716         if (!ppp->closing) {
2717                 ppp->closing = 1;
2718                 ppp_unlock(ppp);
2719                 unregister_netdev(ppp->dev);
2720                 unit_put(&pn->units_idr, ppp->file.index);
2721         } else
2722                 ppp_unlock(ppp);
2723
2724         ppp->file.dead = 1;
2725         ppp->owner = NULL;
2726         wake_up_interruptible(&ppp->file.rwait);
2727
2728         mutex_unlock(&pn->all_ppp_mutex);
2729 }
2730
2731 /*
2732  * Free the memory used by a ppp unit.  This is only called once
2733  * there are no channels connected to the unit and no file structs
2734  * that reference the unit.
2735  */
2736 static void ppp_destroy_interface(struct ppp *ppp)
2737 {
2738         atomic_dec(&ppp_unit_count);
2739
2740         if (!ppp->file.dead || ppp->n_channels) {
2741                 /* "can't happen" */
2742                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2743                            "but dead=%d n_channels=%d !\n",
2744                            ppp, ppp->file.dead, ppp->n_channels);
2745                 return;
2746         }
2747
2748         ppp_ccp_closed(ppp);
2749         if (ppp->vj) {
2750                 slhc_free(ppp->vj);
2751                 ppp->vj = NULL;
2752         }
2753         skb_queue_purge(&ppp->file.xq);
2754         skb_queue_purge(&ppp->file.rq);
2755 #ifdef CONFIG_PPP_MULTILINK
2756         skb_queue_purge(&ppp->mrq);
2757 #endif /* CONFIG_PPP_MULTILINK */
2758 #ifdef CONFIG_PPP_FILTER
2759         kfree(ppp->pass_filter);
2760         ppp->pass_filter = NULL;
2761         kfree(ppp->active_filter);
2762         ppp->active_filter = NULL;
2763 #endif /* CONFIG_PPP_FILTER */
2764
2765         kfree_skb(ppp->xmit_pending);
2766
2767         free_netdev(ppp->dev);
2768 }
2769
2770 /*
2771  * Locate an existing ppp unit.
2772  * The caller should have locked the all_ppp_mutex.
2773  */
2774 static struct ppp *
2775 ppp_find_unit(struct ppp_net *pn, int unit)
2776 {
2777         return unit_find(&pn->units_idr, unit);
2778 }
2779
2780 /*
2781  * Locate an existing ppp channel.
2782  * The caller should have locked the all_channels_lock.
2783  * First we look in the new_channels list, then in the
2784  * all_channels list.  If found in the new_channels list,
2785  * we move it to the all_channels list.  This is for speed
2786  * when we have a lot of channels in use.
2787  */
2788 static struct channel *
2789 ppp_find_channel(struct ppp_net *pn, int unit)
2790 {
2791         struct channel *pch;
2792
2793         list_for_each_entry(pch, &pn->new_channels, list) {
2794                 if (pch->file.index == unit) {
2795                         list_move(&pch->list, &pn->all_channels);
2796                         return pch;
2797                 }
2798         }
2799
2800         list_for_each_entry(pch, &pn->all_channels, list) {
2801                 if (pch->file.index == unit)
2802                         return pch;
2803         }
2804
2805         return NULL;
2806 }
2807
2808 /*
2809  * Connect a PPP channel to a PPP interface unit.
2810  */
2811 static int
2812 ppp_connect_channel(struct channel *pch, int unit)
2813 {
2814         struct ppp *ppp;
2815         struct ppp_net *pn;
2816         int ret = -ENXIO;
2817         int hdrlen;
2818
2819         pn = ppp_pernet(pch->chan_net);
2820
2821         mutex_lock(&pn->all_ppp_mutex);
2822         ppp = ppp_find_unit(pn, unit);
2823         if (!ppp)
2824                 goto out;
2825         write_lock_bh(&pch->upl);
2826         ret = -EINVAL;
2827         if (pch->ppp)
2828                 goto outl;
2829
2830         ppp_lock(ppp);
2831         if (pch->file.hdrlen > ppp->file.hdrlen)
2832                 ppp->file.hdrlen = pch->file.hdrlen;
2833         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2834         if (hdrlen > ppp->dev->hard_header_len)
2835                 ppp->dev->hard_header_len = hdrlen;
2836         list_add_tail(&pch->clist, &ppp->channels);
2837         ++ppp->n_channels;
2838         pch->ppp = ppp;
2839         atomic_inc(&ppp->file.refcnt);
2840         ppp_unlock(ppp);
2841         ret = 0;
2842
2843  outl:
2844         write_unlock_bh(&pch->upl);
2845  out:
2846         mutex_unlock(&pn->all_ppp_mutex);
2847         return ret;
2848 }
2849
2850 /*
2851  * Disconnect a channel from its ppp unit.
2852  */
2853 static int
2854 ppp_disconnect_channel(struct channel *pch)
2855 {
2856         struct ppp *ppp;
2857         int err = -EINVAL;
2858
2859         write_lock_bh(&pch->upl);
2860         ppp = pch->ppp;
2861         pch->ppp = NULL;
2862         write_unlock_bh(&pch->upl);
2863         if (ppp) {
2864                 /* remove it from the ppp unit's list */
2865                 ppp_lock(ppp);
2866                 list_del(&pch->clist);
2867                 if (--ppp->n_channels == 0)
2868                         wake_up_interruptible(&ppp->file.rwait);
2869                 ppp_unlock(ppp);
2870                 if (atomic_dec_and_test(&ppp->file.refcnt))
2871                         ppp_destroy_interface(ppp);
2872                 err = 0;
2873         }
2874         return err;
2875 }
2876
2877 /*
2878  * Free up the resources used by a ppp channel.
2879  */
2880 static void ppp_destroy_channel(struct channel *pch)
2881 {
2882         atomic_dec(&channel_count);
2883
2884         if (!pch->file.dead) {
2885                 /* "can't happen" */
2886                 pr_err("ppp: destroying undead channel %p !\n", pch);
2887                 return;
2888         }
2889         skb_queue_purge(&pch->file.xq);
2890         skb_queue_purge(&pch->file.rq);
2891         kfree(pch);
2892 }
2893
2894 static void __exit ppp_cleanup(void)
2895 {
2896         /* should never happen */
2897         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2898                 pr_err("PPP: removing module but units remain!\n");
2899         unregister_chrdev(PPP_MAJOR, "ppp");
2900         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2901         class_destroy(ppp_class);
2902         unregister_pernet_device(&ppp_net_ops);
2903 }
2904
2905 /*
2906  * Units handling. Caller must protect concurrent access
2907  * by holding all_ppp_mutex
2908  */
2909
2910 static int __unit_alloc(struct idr *p, void *ptr, int n)
2911 {
2912         int unit, err;
2913
2914 again:
2915         if (!idr_pre_get(p, GFP_KERNEL)) {
2916                 pr_err("PPP: No free memory for idr\n");
2917                 return -ENOMEM;
2918         }
2919
2920         err = idr_get_new_above(p, ptr, n, &unit);
2921         if (err < 0) {
2922                 if (err == -EAGAIN)
2923                         goto again;
2924                 return err;
2925         }
2926
2927         return unit;
2928 }
2929
2930 /* associate pointer with specified number */
2931 static int unit_set(struct idr *p, void *ptr, int n)
2932 {
2933         int unit;
2934
2935         unit = __unit_alloc(p, ptr, n);
2936         if (unit < 0)
2937                 return unit;
2938         else if (unit != n) {
2939                 idr_remove(p, unit);
2940                 return -EINVAL;
2941         }
2942
2943         return unit;
2944 }
2945
2946 /* get new free unit number and associate pointer with it */
2947 static int unit_get(struct idr *p, void *ptr)
2948 {
2949         return __unit_alloc(p, ptr, 0);
2950 }
2951
2952 /* put unit number back to a pool */
2953 static void unit_put(struct idr *p, int n)
2954 {
2955         idr_remove(p, n);
2956 }
2957
2958 /* get pointer associated with the number */
2959 static void *unit_find(struct idr *p, int n)
2960 {
2961         return idr_find(p, n);
2962 }
2963
2964 /* Module/initialization stuff */
2965
2966 module_init(ppp_init);
2967 module_exit(ppp_cleanup);
2968
2969 EXPORT_SYMBOL(ppp_register_net_channel);
2970 EXPORT_SYMBOL(ppp_register_channel);
2971 EXPORT_SYMBOL(ppp_unregister_channel);
2972 EXPORT_SYMBOL(ppp_channel_index);
2973 EXPORT_SYMBOL(ppp_unit_number);
2974 EXPORT_SYMBOL(ppp_dev_name);
2975 EXPORT_SYMBOL(ppp_input);
2976 EXPORT_SYMBOL(ppp_input_error);
2977 EXPORT_SYMBOL(ppp_output_wakeup);
2978 EXPORT_SYMBOL(ppp_register_compressor);
2979 EXPORT_SYMBOL(ppp_unregister_compressor);
2980 MODULE_LICENSE("GPL");
2981 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
2982 MODULE_ALIAS("devname:ppp");