drivers/net/ppp/ppp_generic.c

   1 /*
   2  * Generic PPP layer for Linux.
   3  *
   4  * Copyright 1999-2002 Paul Mackerras.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  *
  11  * The generic PPP layer handles the PPP network interfaces, the
  12  * /dev/ppp device, packet and VJ compression, and multilink.
  13  * It talks to PPP `channels' via the interface defined in
  14  * include/linux/ppp_channel.h.  Channels provide the basic means for
  15  * sending and receiving PPP frames on some kind of communications
  16  * channel.
  17  *
  18  * Part of the code in this driver was inspired by the old async-only
  19  * PPP driver, written by Michael Callahan and Al Longyear, and
  20  * subsequently hacked by Paul Mackerras.
  21  *
  22  * ==FILEVERSION 20041108==
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/kmod.h>
  28 #include <linux/init.h>
  29 #include <linux/list.h>
  30 #include <linux/idr.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/poll.h>
  33 #include <linux/ppp_defs.h>
  34 #include <linux/filter.h>
  35 #include <linux/ppp-ioctl.h>
  36 #include <linux/ppp_channel.h>
  37 #include <linux/ppp-comp.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/rtnetlink.h>
  40 #include <linux/if_arp.h>
  41 #include <linux/ip.h>
  42 #include <linux/tcp.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/rwsem.h>
  45 #include <linux/stddef.h>
  46 #include <linux/device.h>
  47 #include <linux/mutex.h>
  48 #include <linux/slab.h>
  49 #include <asm/unaligned.h>
  50 #include <net/slhc_vj.h>
  51 #include <linux/atomic.h>
  52
  53 #include <linux/nsproxy.h>
  54 #include <net/net_namespace.h>
  55 #include <net/netns/generic.h>
  56
  57 #define PPP_VERSION     "2.4.2"
  58
  59 /*
  60  * Network protocols we support.
  61  */
  62 #define NP_IP   0               /* Internet Protocol V4 */
  63 #define NP_IPV6 1               /* Internet Protocol V6 */
  64 #define NP_IPX  2               /* IPX protocol */
  65 #define NP_AT   3               /* Appletalk protocol */
  66 #define NP_MPLS_UC 4            /* MPLS unicast */
  67 #define NP_MPLS_MC 5            /* MPLS multicast */
  68 #define NUM_NP  6               /* Number of NPs. */
  69
  70 #define MPHDRLEN        6       /* multilink protocol header length */
  71 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  72
  73 /*
  74  * An instance of /dev/ppp can be associated with either a ppp
  75  * interface unit or a ppp channel.  In both cases, file->private_data
  76  * points to one of these.
  77  */
  78 struct ppp_file {
  79         enum {
  80                 INTERFACE=1, CHANNEL
  81         }               kind;
  82         struct sk_buff_head xq;         /* pppd transmit queue */
  83         struct sk_buff_head rq;         /* receive queue for pppd */
  84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  86         int             hdrlen;         /* space to leave for headers */
  87         int             index;          /* interface unit / channel number */
  88         int             dead;           /* unit/channel has been shut down */
  89 };
  90
  91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  92
  93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  95
  96 /*
  97  * Data structure to hold primary network stats for which
  98  * we want to use 64 bit storage.  Other network stats
  99  * are stored in dev->stats of the ppp strucute.
 100  */
 101 struct ppp_link_stats {
 102         u64 rx_packets;
 103         u64 tx_packets;
 104         u64 rx_bytes;
 105         u64 tx_bytes;
 106 };
 107
 108 /*
 109  * Data structure describing one ppp unit.
 110  * A ppp unit corresponds to a ppp network interface device
 111  * and represents a multilink bundle.
 112  * It can have 0 or more ppp channels connected to it.
 113  */
 114 struct ppp {
 115         struct ppp_file file;           /* stuff for read/write/poll 0 */
 116         struct file     *owner;         /* file that owns this unit 48 */
 117         struct list_head channels;      /* list of attached channels 4c */
 118         int             n_channels;     /* how many channels are attached 54 */
 119         spinlock_t      rlock;          /* lock for receive side 58 */
 120         spinlock_t      wlock;          /* lock for transmit side 5c */
 121         int             mru;            /* max receive unit 60 */
 122         unsigned int    flags;          /* control bits 64 */
 123         unsigned int    xstate;         /* transmit state bits 68 */
 124         unsigned int    rstate;         /* receive state bits 6c */
 125         int             debug;          /* debug flags 70 */
 126         struct slcompress *vj;          /* state for VJ header compression */
 127         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 128         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 129         struct compressor *xcomp;       /* transmit packet compressor 8c */
 130         void            *xc_state;      /* its internal state 90 */
 131         struct compressor *rcomp;       /* receive decompressor 94 */
 132         void            *rc_state;      /* its internal state 98 */
 133         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 134         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 135         struct net_device *dev;         /* network interface device a4 */
 136         int             closing;        /* is device closing down? a8 */
 137 #ifdef CONFIG_PPP_MULTILINK
 138         int             nxchan;         /* next channel to send something on */
 139         u32             nxseq;          /* next sequence number to send */
 140         int             mrru;           /* MP: max reconst. receive unit */
 141         u32             nextseq;        /* MP: seq no of next packet */
 142         u32             minseq;         /* MP: min of most recent seqnos */
 143         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 144 #endif /* CONFIG_PPP_MULTILINK */
 145 #ifdef CONFIG_PPP_FILTER
 146         struct sk_filter *pass_filter;  /* filter for packets to pass */
 147         struct sk_filter *active_filter;/* filter for pkts to reset idle */
 148 #endif /* CONFIG_PPP_FILTER */
 149         struct net      *ppp_net;       /* the net we belong to */
 150         struct ppp_link_stats stats64;  /* 64 bit network stats */
 151 };
 152
 153 /*
 154  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 155  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 156  * SC_MUST_COMP
 157  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 158  * Bits in xstate: SC_COMP_RUN
 159  */
 160 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 161                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 162                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 163
 164 /*
 165  * Private data structure for each channel.
 166  * This includes the data structure used for multilink.
 167  */
 168 struct channel {
 169         struct ppp_file file;           /* stuff for read/write/poll */
 170         struct list_head list;          /* link in all/new_channels list */
 171         struct ppp_channel *chan;       /* public channel data structure */
 172         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 173         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 174         struct ppp      *ppp;           /* ppp unit we're connected to */
 175         struct net      *chan_net;      /* the net channel belongs to */
 176         struct list_head clist;         /* link in list of channels per unit */
 177         rwlock_t        upl;            /* protects `ppp' */
 178 #ifdef CONFIG_PPP_MULTILINK
 179         u8              avail;          /* flag used in multilink stuff */
 180         u8              had_frag;       /* >= 1 fragments have been sent */
 181         u32             lastseq;        /* MP: last sequence # received */
 182         int             speed;          /* speed of the corresponding ppp channel*/
 183 #endif /* CONFIG_PPP_MULTILINK */
 184 };
 185
 186 /*
 187  * SMP locking issues:
 188  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 189  * list and the ppp.n_channels field, you need to take both locks
 190  * before you modify them.
 191  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 192  * channel.downl.
 193  */
 194
 195 static DEFINE_MUTEX(ppp_mutex);
 196 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 197 static atomic_t channel_count = ATOMIC_INIT(0);
 198
 199 /* per-net private data for this module */
 200 static int ppp_net_id __read_mostly;
 201 struct ppp_net {
 202         /* units to ppp mapping */
 203         struct idr units_idr;
 204
 205         /*
 206          * all_ppp_mutex protects the units_idr mapping.
 207          * It also ensures that finding a ppp unit in the units_idr
 208          * map and updating its file.refcnt field is atomic.
 209          */
 210         struct mutex all_ppp_mutex;
 211
 212         /* channels */
 213         struct list_head all_channels;
 214         struct list_head new_channels;
 215         int last_channel_index;
 216
 217         /*
 218          * all_channels_lock protects all_channels and
 219          * last_channel_index, and the atomicity of find
 220          * a channel and updating its file.refcnt field.
 221          */
 222         spinlock_t all_channels_lock;
 223 };
 224
 225 /* Get the PPP protocol number from a skb */
 226 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 227
 228 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 229 #define PPP_MAX_RQLEN   32
 230
 231 /*
 232  * Maximum number of multilink fragments queued up.
 233  * This has to be large enough to cope with the maximum latency of
 234  * the slowest channel relative to the others.  Strictly it should
 235  * depend on the number of channels and their characteristics.
 236  */
 237 #define PPP_MP_MAX_QLEN 128
 238
 239 /* Multilink header bits. */
 240 #define B       0x80            /* this fragment begins a packet */
 241 #define E       0x40            /* this fragment ends a packet */
 242
 243 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 244 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 245 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 246
 247 /* Prototypes. */
 248 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 249                         struct file *file, unsigned int cmd, unsigned long arg);
 250 static void ppp_xmit_process(struct ppp *ppp);
 251 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 252 static void ppp_push(struct ppp *ppp);
 253 static void ppp_channel_push(struct channel *pch);
 254 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 255                               struct channel *pch);
 256 static void ppp_receive_error(struct ppp *ppp);
 257 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 258 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 259                                             struct sk_buff *skb);
 260 #ifdef CONFIG_PPP_MULTILINK
 261 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 262                                 struct channel *pch);
 263 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 264 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 265 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 266 #endif /* CONFIG_PPP_MULTILINK */
 267 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 268 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 269 static void ppp_ccp_closed(struct ppp *ppp);
 270 static struct compressor *find_compressor(int type);
 271 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 272 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 273 static void init_ppp_file(struct ppp_file *pf, int kind);
 274 static void ppp_shutdown_interface(struct ppp *ppp);
 275 static void ppp_destroy_interface(struct ppp *ppp);
 276 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 277 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 278 static int ppp_connect_channel(struct channel *pch, int unit);
 279 static int ppp_disconnect_channel(struct channel *pch);
 280 static void ppp_destroy_channel(struct channel *pch);
 281 static int unit_get(struct idr *p, void *ptr);
 282 static int unit_set(struct idr *p, void *ptr, int n);
 283 static void unit_put(struct idr *p, int n);
 284 static void *unit_find(struct idr *p, int n);
 285
 286 static struct class *ppp_class;
 287
 288 /* per net-namespace data */
 289 static inline struct ppp_net *ppp_pernet(struct net *net)
 290 {
 291         BUG_ON(!net);
 292
 293         return net_generic(net, ppp_net_id);
 294 }
 295
 296 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 297 static inline int proto_to_npindex(int proto)
 298 {
 299         switch (proto) {
 300         case PPP_IP:
 301                 return NP_IP;
 302         case PPP_IPV6:
 303                 return NP_IPV6;
 304         case PPP_IPX:
 305                 return NP_IPX;
 306         case PPP_AT:
 307                 return NP_AT;
 308         case PPP_MPLS_UC:
 309                 return NP_MPLS_UC;
 310         case PPP_MPLS_MC:
 311                 return NP_MPLS_MC;
 312         }
 313         return -EINVAL;
 314 }
 315
 316 /* Translates an NP index into a PPP protocol number */
 317 static const int npindex_to_proto[NUM_NP] = {
 318         PPP_IP,
 319         PPP_IPV6,
 320         PPP_IPX,
 321         PPP_AT,
 322         PPP_MPLS_UC,
 323         PPP_MPLS_MC,
 324 };
 325
 326 /* Translates an ethertype into an NP index */
 327 static inline int ethertype_to_npindex(int ethertype)
 328 {
 329         switch (ethertype) {
 330         case ETH_P_IP:
 331                 return NP_IP;
 332         case ETH_P_IPV6:
 333                 return NP_IPV6;
 334         case ETH_P_IPX:
 335                 return NP_IPX;
 336         case ETH_P_PPPTALK:
 337         case ETH_P_ATALK:
 338                 return NP_AT;
 339         case ETH_P_MPLS_UC:
 340                 return NP_MPLS_UC;
 341         case ETH_P_MPLS_MC:
 342                 return NP_MPLS_MC;
 343         }
 344         return -1;
 345 }
 346
 347 /* Translates an NP index into an ethertype */
 348 static const int npindex_to_ethertype[NUM_NP] = {
 349         ETH_P_IP,
 350         ETH_P_IPV6,
 351         ETH_P_IPX,
 352         ETH_P_PPPTALK,
 353         ETH_P_MPLS_UC,
 354         ETH_P_MPLS_MC,
 355 };
 356
 357 /*
 358  * Locking shorthand.
 359  */
 360 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 361 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 362 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 363 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 364 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 365                                      ppp_recv_lock(ppp); } while (0)
 366 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 367                                      ppp_xmit_unlock(ppp); } while (0)
 368
 369 /*
 370  * /dev/ppp device routines.
 371  * The /dev/ppp device is used by pppd to control the ppp unit.
 372  * It supports the read, write, ioctl and poll functions.
 373  * Open instances of /dev/ppp can be in one of three states:
 374  * unattached, attached to a ppp unit, or attached to a ppp channel.
 375  */
 376 static int ppp_open(struct inode *inode, struct file *file)
 377 {
 378         /*
 379          * This could (should?) be enforced by the permissions on /dev/ppp.
 380          */
 381         if (!capable(CAP_NET_ADMIN))
 382                 return -EPERM;
 383         return 0;
 384 }
 385
 386 static int ppp_release(struct inode *unused, struct file *file)
 387 {
 388         struct ppp_file *pf = file->private_data;
 389         struct ppp *ppp;
 390
 391         if (pf) {
 392                 file->private_data = NULL;
 393                 if (pf->kind == INTERFACE) {
 394                         ppp = PF_TO_PPP(pf);
 395                         if (file == ppp->owner)
 396                                 ppp_shutdown_interface(ppp);
 397                 }
 398                 if (atomic_dec_and_test(&pf->refcnt)) {
 399                         switch (pf->kind) {
 400                         case INTERFACE:
 401                                 ppp_destroy_interface(PF_TO_PPP(pf));
 402                                 break;
 403                         case CHANNEL:
 404                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 405                                 break;
 406                         }
 407                 }
 408         }
 409         return 0;
 410 }
 411
 412 static ssize_t ppp_read(struct file *file, char __user *buf,
 413                         size_t count, loff_t *ppos)
 414 {
 415         struct ppp_file *pf = file->private_data;
 416         DECLARE_WAITQUEUE(wait, current);
 417         ssize_t ret;
 418         struct sk_buff *skb = NULL;
 419         struct iovec iov;
 420
 421         ret = count;
 422
 423         if (!pf)
 424                 return -ENXIO;
 425         add_wait_queue(&pf->rwait, &wait);
 426         for (;;) {
 427                 set_current_state(TASK_INTERRUPTIBLE);
 428                 skb = skb_dequeue(&pf->rq);
 429                 if (skb)
 430                         break;
 431                 ret = 0;
 432                 if (pf->dead)
 433                         break;
 434                 if (pf->kind == INTERFACE) {
 435                         /*
 436                          * Return 0 (EOF) on an interface that has no
 437                          * channels connected, unless it is looping
 438                          * network traffic (demand mode).
 439                          */
 440                         struct ppp *ppp = PF_TO_PPP(pf);
 441                         if (ppp->n_channels == 0 &&
 442                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 443                                 break;
 444                 }
 445                 ret = -EAGAIN;
 446                 if (file->f_flags & O_NONBLOCK)
 447                         break;
 448                 ret = -ERESTARTSYS;
 449                 if (signal_pending(current))
 450                         break;
 451                 schedule();
 452         }
 453         set_current_state(TASK_RUNNING);
 454         remove_wait_queue(&pf->rwait, &wait);
 455
 456         if (!skb)
 457                 goto out;
 458
 459         ret = -EOVERFLOW;
 460         if (skb->len > count)
 461                 goto outf;
 462         ret = -EFAULT;
 463         iov.iov_base = buf;
 464         iov.iov_len = count;
 465         if (skb_copy_datagram_iovec(skb, 0, &iov, skb->len))
 466                 goto outf;
 467         ret = skb->len;
 468
 469  outf:
 470         kfree_skb(skb);
 471  out:
 472         return ret;
 473 }
 474
 475 static ssize_t ppp_write(struct file *file, const char __user *buf,
 476                          size_t count, loff_t *ppos)
 477 {
 478         struct ppp_file *pf = file->private_data;
 479         struct sk_buff *skb;
 480         ssize_t ret;
 481
 482         if (!pf)
 483                 return -ENXIO;
 484         ret = -ENOMEM;
 485         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 486         if (!skb)
 487                 goto out;
 488         skb_reserve(skb, pf->hdrlen);
 489         ret = -EFAULT;
 490         if (copy_from_user(skb_put(skb, count), buf, count)) {
 491                 kfree_skb(skb);
 492                 goto out;
 493         }
 494
 495         skb_queue_tail(&pf->xq, skb);
 496
 497         switch (pf->kind) {
 498         case INTERFACE:
 499                 ppp_xmit_process(PF_TO_PPP(pf));
 500                 break;
 501         case CHANNEL:
 502                 ppp_channel_push(PF_TO_CHANNEL(pf));
 503                 break;
 504         }
 505
 506         ret = count;
 507
 508  out:
 509         return ret;
 510 }
 511
 512 /* No kernel lock - fine */
 513 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 514 {
 515         struct ppp_file *pf = file->private_data;
 516         unsigned int mask;
 517
 518         if (!pf)
 519                 return 0;
 520         poll_wait(file, &pf->rwait, wait);
 521         mask = POLLOUT | POLLWRNORM;
 522         if (skb_peek(&pf->rq))
 523                 mask |= POLLIN | POLLRDNORM;
 524         if (pf->dead)
 525                 mask |= POLLHUP;
 526         else if (pf->kind == INTERFACE) {
 527                 /* see comment in ppp_read */
 528                 struct ppp *ppp = PF_TO_PPP(pf);
 529                 if (ppp->n_channels == 0 &&
 530                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 531                         mask |= POLLIN | POLLRDNORM;
 532         }
 533
 534         return mask;
 535 }
 536
 537 #ifdef CONFIG_PPP_FILTER
 538 static int get_filter(void __user *arg, struct sock_filter **p)
 539 {
 540         struct sock_fprog uprog;
 541         struct sock_filter *code = NULL;
 542         int len;
 543
 544         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 545                 return -EFAULT;
 546
 547         if (!uprog.len) {
 548                 *p = NULL;
 549                 return 0;
 550         }
 551
 552         len = uprog.len * sizeof(struct sock_filter);
 553         code = memdup_user(uprog.filter, len);
 554         if (IS_ERR(code))
 555                 return PTR_ERR(code);
 556
 557         *p = code;
 558         return uprog.len;
 559 }
 560 #endif /* CONFIG_PPP_FILTER */
 561
 562 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 563 {
 564         struct ppp_file *pf = file->private_data;
 565         struct ppp *ppp;
 566         int err = -EFAULT, val, val2, i;
 567         struct ppp_idle idle;
 568         struct npioctl npi;
 569         int unit, cflags;
 570         struct slcompress *vj;
 571         void __user *argp = (void __user *)arg;
 572         int __user *p = argp;
 573
 574         if (!pf)
 575                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
 576                                         pf, file, cmd, arg);
 577
 578         if (cmd == PPPIOCDETACH) {
 579                 /*
 580                  * We have to be careful here... if the file descriptor
 581                  * has been dup'd, we could have another process in the
 582                  * middle of a poll using the same file *, so we had
 583                  * better not free the interface data structures -
 584                  * instead we fail the ioctl.  Even in this case, we
 585                  * shut down the interface if we are the owner of it.
 586                  * Actually, we should get rid of PPPIOCDETACH, userland
 587                  * (i.e. pppd) could achieve the same effect by closing
 588                  * this fd and reopening /dev/ppp.
 589                  */
 590                 err = -EINVAL;
 591                 mutex_lock(&ppp_mutex);
 592                 if (pf->kind == INTERFACE) {
 593                         ppp = PF_TO_PPP(pf);
 594                         if (file == ppp->owner)
 595                                 ppp_shutdown_interface(ppp);
 596                 }
 597                 if (atomic_long_read(&file->f_count) <= 2) {
 598                         ppp_release(NULL, file);
 599                         err = 0;
 600                 } else
 601                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 602                                 atomic_long_read(&file->f_count));
 603                 mutex_unlock(&ppp_mutex);
 604                 return err;
 605         }
 606
 607         if (pf->kind == CHANNEL) {
 608                 struct channel *pch;
 609                 struct ppp_channel *chan;
 610
 611                 mutex_lock(&ppp_mutex);
 612                 pch = PF_TO_CHANNEL(pf);
 613
 614                 switch (cmd) {
 615                 case PPPIOCCONNECT:
 616                         if (get_user(unit, p))
 617                                 break;
 618                         err = ppp_connect_channel(pch, unit);
 619                         break;
 620
 621                 case PPPIOCDISCONN:
 622                         err = ppp_disconnect_channel(pch);
 623                         break;
 624
 625                 default:
 626                         down_read(&pch->chan_sem);
 627                         chan = pch->chan;
 628                         err = -ENOTTY;
 629                         if (chan && chan->ops->ioctl)
 630                                 err = chan->ops->ioctl(chan, cmd, arg);
 631                         up_read(&pch->chan_sem);
 632                 }
 633                 mutex_unlock(&ppp_mutex);
 634                 return err;
 635         }
 636
 637         if (pf->kind != INTERFACE) {
 638                 /* can't happen */
 639                 pr_err("PPP: not interface or channel??\n");
 640                 return -EINVAL;
 641         }
 642
 643         mutex_lock(&ppp_mutex);
 644         ppp = PF_TO_PPP(pf);
 645         switch (cmd) {
 646         case PPPIOCSMRU:
 647                 if (get_user(val, p))
 648                         break;
 649                 ppp->mru = val;
 650                 err = 0;
 651                 break;
 652
 653         case PPPIOCSFLAGS:
 654                 if (get_user(val, p))
 655                         break;
 656                 ppp_lock(ppp);
 657                 cflags = ppp->flags & ~val;
 658                 ppp->flags = val & SC_FLAG_BITS;
 659                 ppp_unlock(ppp);
 660                 if (cflags & SC_CCP_OPEN)
 661                         ppp_ccp_closed(ppp);
 662                 err = 0;
 663                 break;
 664
 665         case PPPIOCGFLAGS:
 666                 val = ppp->flags | ppp->xstate | ppp->rstate;
 667                 if (put_user(val, p))
 668                         break;
 669                 err = 0;
 670                 break;
 671
 672         case PPPIOCSCOMPRESS:
 673                 err = ppp_set_compress(ppp, arg);
 674                 break;
 675
 676         case PPPIOCGUNIT:
 677                 if (put_user(ppp->file.index, p))
 678                         break;
 679                 err = 0;
 680                 break;
 681
 682         case PPPIOCSDEBUG:
 683                 if (get_user(val, p))
 684                         break;
 685                 ppp->debug = val;
 686                 err = 0;
 687                 break;
 688
 689         case PPPIOCGDEBUG:
 690                 if (put_user(ppp->debug, p))
 691                         break;
 692                 err = 0;
 693                 break;
 694
 695         case PPPIOCGIDLE:
 696                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 697                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 698                 if (copy_to_user(argp, &idle, sizeof(idle)))
 699                         break;
 700                 err = 0;
 701                 break;
 702
 703         case PPPIOCSMAXCID:
 704                 if (get_user(val, p))
 705                         break;
 706                 val2 = 15;
 707                 if ((val >> 16) != 0) {
 708                         val2 = val >> 16;
 709                         val &= 0xffff;
 710                 }
 711                 vj = slhc_init(val2+1, val+1);
 712                 if (!vj) {
 713                         netdev_err(ppp->dev,
 714                                    "PPP: no memory (VJ compressor)\n");
 715                         err = -ENOMEM;
 716                         break;
 717                 }
 718                 ppp_lock(ppp);
 719                 if (ppp->vj)
 720                         slhc_free(ppp->vj);
 721                 ppp->vj = vj;
 722                 ppp_unlock(ppp);
 723                 err = 0;
 724                 break;
 725
 726         case PPPIOCGNPMODE:
 727         case PPPIOCSNPMODE:
 728                 if (copy_from_user(&npi, argp, sizeof(npi)))
 729                         break;
 730                 err = proto_to_npindex(npi.protocol);
 731                 if (err < 0)
 732                         break;
 733                 i = err;
 734                 if (cmd == PPPIOCGNPMODE) {
 735                         err = -EFAULT;
 736                         npi.mode = ppp->npmode[i];
 737                         if (copy_to_user(argp, &npi, sizeof(npi)))
 738                                 break;
 739                 } else {
 740                         ppp->npmode[i] = npi.mode;
 741                         /* we may be able to transmit more packets now (??) */
 742                         netif_wake_queue(ppp->dev);
 743                 }
 744                 err = 0;
 745                 break;
 746
 747 #ifdef CONFIG_PPP_FILTER
 748         case PPPIOCSPASS:
 749         {
 750                 struct sock_filter *code;
 751
 752                 err = get_filter(argp, &code);
 753                 if (err >= 0) {
 754                         struct sock_fprog_kern fprog = {
 755                                 .len = err,
 756                                 .filter = code,
 757                         };
 758
 759                         ppp_lock(ppp);
 760                         if (ppp->pass_filter)
 761                                 sk_unattached_filter_destroy(ppp->pass_filter);
 762                         err = sk_unattached_filter_create(&ppp->pass_filter,
 763                                                           &fprog);
 764                         kfree(code);
 765                         ppp_unlock(ppp);
 766                 }
 767                 break;
 768         }
 769         case PPPIOCSACTIVE:
 770         {
 771                 struct sock_filter *code;
 772
 773                 err = get_filter(argp, &code);
 774                 if (err >= 0) {
 775                         struct sock_fprog_kern fprog = {
 776                                 .len = err,
 777                                 .filter = code,
 778                         };
 779
 780                         ppp_lock(ppp);
 781                         if (ppp->active_filter)
 782                                 sk_unattached_filter_destroy(ppp->active_filter);
 783                         err = sk_unattached_filter_create(&ppp->active_filter,
 784                                                           &fprog);
 785                         kfree(code);
 786                         ppp_unlock(ppp);
 787                 }
 788                 break;
 789         }
 790 #endif /* CONFIG_PPP_FILTER */
 791
 792 #ifdef CONFIG_PPP_MULTILINK
 793         case PPPIOCSMRRU:
 794                 if (get_user(val, p))
 795                         break;
 796                 ppp_recv_lock(ppp);
 797                 ppp->mrru = val;
 798                 ppp_recv_unlock(ppp);
 799                 err = 0;
 800                 break;
 801 #endif /* CONFIG_PPP_MULTILINK */
 802
 803         default:
 804                 err = -ENOTTY;
 805         }
 806         mutex_unlock(&ppp_mutex);
 807         return err;
 808 }
 809
 810 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 811                         struct file *file, unsigned int cmd, unsigned long arg)
 812 {
 813         int unit, err = -EFAULT;
 814         struct ppp *ppp;
 815         struct channel *chan;
 816         struct ppp_net *pn;
 817         int __user *p = (int __user *)arg;
 818
 819         mutex_lock(&ppp_mutex);
 820         switch (cmd) {
 821         case PPPIOCNEWUNIT:
 822                 /* Create a new ppp unit */
 823                 if (get_user(unit, p))
 824                         break;
 825                 ppp = ppp_create_interface(net, unit, &err);
 826                 if (!ppp)
 827                         break;
 828                 file->private_data = &ppp->file;
 829                 ppp->owner = file;
 830                 err = -EFAULT;
 831                 if (put_user(ppp->file.index, p))
 832                         break;
 833                 err = 0;
 834                 break;
 835
 836         case PPPIOCATTACH:
 837                 /* Attach to an existing ppp unit */
 838                 if (get_user(unit, p))
 839                         break;
 840                 err = -ENXIO;
 841                 pn = ppp_pernet(net);
 842                 mutex_lock(&pn->all_ppp_mutex);
 843                 ppp = ppp_find_unit(pn, unit);
 844                 if (ppp) {
 845                         atomic_inc(&ppp->file.refcnt);
 846                         file->private_data = &ppp->file;
 847                         err = 0;
 848                 }
 849                 mutex_unlock(&pn->all_ppp_mutex);
 850                 break;
 851
 852         case PPPIOCATTCHAN:
 853                 if (get_user(unit, p))
 854                         break;
 855                 err = -ENXIO;
 856                 pn = ppp_pernet(net);
 857                 spin_lock_bh(&pn->all_channels_lock);
 858                 chan = ppp_find_channel(pn, unit);
 859                 if (chan) {
 860                         atomic_inc(&chan->file.refcnt);
 861                         file->private_data = &chan->file;
 862                         err = 0;
 863                 }
 864                 spin_unlock_bh(&pn->all_channels_lock);
 865                 break;
 866
 867         default:
 868                 err = -ENOTTY;
 869         }
 870         mutex_unlock(&ppp_mutex);
 871         return err;
 872 }
 873
 874 static const struct file_operations ppp_device_fops = {
 875         .owner          = THIS_MODULE,
 876         .read           = ppp_read,
 877         .write          = ppp_write,
 878         .poll           = ppp_poll,
 879         .unlocked_ioctl = ppp_ioctl,
 880         .open           = ppp_open,
 881         .release        = ppp_release,
 882         .llseek         = noop_llseek,
 883 };
 884
 885 static __net_init int ppp_init_net(struct net *net)
 886 {
 887         struct ppp_net *pn = net_generic(net, ppp_net_id);
 888
 889         idr_init(&pn->units_idr);
 890         mutex_init(&pn->all_ppp_mutex);
 891
 892         INIT_LIST_HEAD(&pn->all_channels);
 893         INIT_LIST_HEAD(&pn->new_channels);
 894
 895         spin_lock_init(&pn->all_channels_lock);
 896
 897         return 0;
 898 }
 899
 900 static __net_exit void ppp_exit_net(struct net *net)
 901 {
 902         struct ppp_net *pn = net_generic(net, ppp_net_id);
 903
 904         idr_destroy(&pn->units_idr);
 905 }
 906
 907 static struct pernet_operations ppp_net_ops = {
 908         .init = ppp_init_net,
 909         .exit = ppp_exit_net,
 910         .id   = &ppp_net_id,
 911         .size = sizeof(struct ppp_net),
 912 };
 913
 914 #define PPP_MAJOR       108
 915
 916 /* Called at boot time if ppp is compiled into the kernel,
 917    or at module load time (from init_module) if compiled as a module. */
 918 static int __init ppp_init(void)
 919 {
 920         int err;
 921
 922         pr_info("PPP generic driver version " PPP_VERSION "\n");
 923
 924         err = register_pernet_device(&ppp_net_ops);
 925         if (err) {
 926                 pr_err("failed to register PPP pernet device (%d)\n", err);
 927                 goto out;
 928         }
 929
 930         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 931         if (err) {
 932                 pr_err("failed to register PPP device (%d)\n", err);
 933                 goto out_net;
 934         }
 935
 936         ppp_class = class_create(THIS_MODULE, "ppp");
 937         if (IS_ERR(ppp_class)) {
 938                 err = PTR_ERR(ppp_class);
 939                 goto out_chrdev;
 940         }
 941
 942         /* not a big deal if we fail here :-) */
 943         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 944
 945         return 0;
 946
 947 out_chrdev:
 948         unregister_chrdev(PPP_MAJOR, "ppp");
 949 out_net:
 950         unregister_pernet_device(&ppp_net_ops);
 951 out:
 952         return err;
 953 }
 954
 955 /*
 956  * Network interface unit routines.
 957  */
 958 static netdev_tx_t
 959 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 960 {
 961         struct ppp *ppp = netdev_priv(dev);
 962         int npi, proto;
 963         unsigned char *pp;
 964
 965         npi = ethertype_to_npindex(ntohs(skb->protocol));
 966         if (npi < 0)
 967                 goto outf;
 968
 969         /* Drop, accept or reject the packet */
 970         switch (ppp->npmode[npi]) {
 971         case NPMODE_PASS:
 972                 break;
 973         case NPMODE_QUEUE:
 974                 /* it would be nice to have a way to tell the network
 975                    system to queue this one up for later. */
 976                 goto outf;
 977         case NPMODE_DROP:
 978         case NPMODE_ERROR:
 979                 goto outf;
 980         }
 981
 982         /* Put the 2-byte PPP protocol number on the front,
 983            making sure there is room for the address and control fields. */
 984         if (skb_cow_head(skb, PPP_HDRLEN))
 985                 goto outf;
 986
 987         pp = skb_push(skb, 2);
 988         proto = npindex_to_proto[npi];
 989         put_unaligned_be16(proto, pp);
 990
 991         skb_queue_tail(&ppp->file.xq, skb);
 992         ppp_xmit_process(ppp);
 993         return NETDEV_TX_OK;
 994
 995  outf:
 996         kfree_skb(skb);
 997         ++dev->stats.tx_dropped;
 998         return NETDEV_TX_OK;
 999 }
1000
1001 static int
1002 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1003 {
1004         struct ppp *ppp = netdev_priv(dev);
1005         int err = -EFAULT;
1006         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1007         struct ppp_stats stats;
1008         struct ppp_comp_stats cstats;
1009         char *vers;
1010
1011         switch (cmd) {
1012         case SIOCGPPPSTATS:
1013                 ppp_get_stats(ppp, &stats);
1014                 if (copy_to_user(addr, &stats, sizeof(stats)))
1015                         break;
1016                 err = 0;
1017                 break;
1018
1019         case SIOCGPPPCSTATS:
1020                 memset(&cstats, 0, sizeof(cstats));
1021                 if (ppp->xc_state)
1022                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1023                 if (ppp->rc_state)
1024                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1025                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1026                         break;
1027                 err = 0;
1028                 break;
1029
1030         case SIOCGPPPVER:
1031                 vers = PPP_VERSION;
1032                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1033                         break;
1034                 err = 0;
1035                 break;
1036
1037         default:
1038                 err = -EINVAL;
1039         }
1040
1041         return err;
1042 }
1043
1044 static struct rtnl_link_stats64*
1045 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1046 {
1047         struct ppp *ppp = netdev_priv(dev);
1048
1049         ppp_recv_lock(ppp);
1050         stats64->rx_packets = ppp->stats64.rx_packets;
1051         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1052         ppp_recv_unlock(ppp);
1053
1054         ppp_xmit_lock(ppp);
1055         stats64->tx_packets = ppp->stats64.tx_packets;
1056         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1057         ppp_xmit_unlock(ppp);
1058
1059         stats64->rx_errors        = dev->stats.rx_errors;
1060         stats64->tx_errors        = dev->stats.tx_errors;
1061         stats64->rx_dropped       = dev->stats.rx_dropped;
1062         stats64->tx_dropped       = dev->stats.tx_dropped;
1063         stats64->rx_length_errors = dev->stats.rx_length_errors;
1064
1065         return stats64;
1066 }
1067
1068 static struct lock_class_key ppp_tx_busylock;
1069 static int ppp_dev_init(struct net_device *dev)
1070 {
1071         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1072         return 0;
1073 }
1074
1075 static const struct net_device_ops ppp_netdev_ops = {
1076         .ndo_init        = ppp_dev_init,
1077         .ndo_start_xmit  = ppp_start_xmit,
1078         .ndo_do_ioctl    = ppp_net_ioctl,
1079         .ndo_get_stats64 = ppp_get_stats64,
1080 };
1081
1082 static void ppp_setup(struct net_device *dev)
1083 {
1084         dev->netdev_ops = &ppp_netdev_ops;
1085         dev->hard_header_len = PPP_HDRLEN;
1086         dev->mtu = PPP_MRU;
1087         dev->addr_len = 0;
1088         dev->tx_queue_len = 3;
1089         dev->type = ARPHRD_PPP;
1090         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1091         dev->features |= NETIF_F_NETNS_LOCAL;
1092         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1093 }
1094
1095 /*
1096  * Transmit-side routines.
1097  */
1098
1099 /*
1100  * Called to do any work queued up on the transmit side
1101  * that can now be done.
1102  */
1103 static void
1104 ppp_xmit_process(struct ppp *ppp)
1105 {
1106         struct sk_buff *skb;
1107
1108         ppp_xmit_lock(ppp);
1109         if (!ppp->closing) {
1110                 ppp_push(ppp);
1111                 while (!ppp->xmit_pending &&
1112                        (skb = skb_dequeue(&ppp->file.xq)))
1113                         ppp_send_frame(ppp, skb);
1114                 /* If there's no work left to do, tell the core net
1115                    code that we can accept some more. */
1116                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1117                         netif_wake_queue(ppp->dev);
1118                 else
1119                         netif_stop_queue(ppp->dev);
1120         }
1121         ppp_xmit_unlock(ppp);
1122 }
1123
1124 static inline struct sk_buff *
1125 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1126 {
1127         struct sk_buff *new_skb;
1128         int len;
1129         int new_skb_size = ppp->dev->mtu +
1130                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1131         int compressor_skb_size = ppp->dev->mtu +
1132                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1133         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1134         if (!new_skb) {
1135                 if (net_ratelimit())
1136                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1137                 return NULL;
1138         }
1139         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1140                 skb_reserve(new_skb,
1141                             ppp->dev->hard_header_len - PPP_HDRLEN);
1142
1143         /* compressor still expects A/C bytes in hdr */
1144         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1145                                    new_skb->data, skb->len + 2,
1146                                    compressor_skb_size);
1147         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1148                 consume_skb(skb);
1149                 skb = new_skb;
1150                 skb_put(skb, len);
1151                 skb_pull(skb, 2);       /* pull off A/C bytes */
1152         } else if (len == 0) {
1153                 /* didn't compress, or CCP not up yet */
1154                 consume_skb(new_skb);
1155                 new_skb = skb;
1156         } else {
1157                 /*
1158                  * (len < 0)
1159                  * MPPE requires that we do not send unencrypted
1160                  * frames.  The compressor will return -1 if we
1161                  * should drop the frame.  We cannot simply test
1162                  * the compress_proto because MPPE and MPPC share
1163                  * the same number.
1164                  */
1165                 if (net_ratelimit())
1166                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1167                 kfree_skb(skb);
1168                 consume_skb(new_skb);
1169                 new_skb = NULL;
1170         }
1171         return new_skb;
1172 }
1173
1174 /*
1175  * Compress and send a frame.
1176  * The caller should have locked the xmit path,
1177  * and xmit_pending should be 0.
1178  */
1179 static void
1180 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1181 {
1182         int proto = PPP_PROTO(skb);
1183         struct sk_buff *new_skb;
1184         int len;
1185         unsigned char *cp;
1186
1187         if (proto < 0x8000) {
1188 #ifdef CONFIG_PPP_FILTER
1189                 /* check if we should pass this packet */
1190                 /* the filter instructions are constructed assuming
1191                    a four-byte PPP header on each packet */
1192                 *skb_push(skb, 2) = 1;
1193                 if (ppp->pass_filter &&
1194                     SK_RUN_FILTER(ppp->pass_filter, skb) == 0) {
1195                         if (ppp->debug & 1)
1196                                 netdev_printk(KERN_DEBUG, ppp->dev,
1197                                               "PPP: outbound frame "
1198                                               "not passed\n");
1199                         kfree_skb(skb);
1200                         return;
1201                 }
1202                 /* if this packet passes the active filter, record the time */
1203                 if (!(ppp->active_filter &&
1204                       SK_RUN_FILTER(ppp->active_filter, skb) == 0))
1205                         ppp->last_xmit = jiffies;
1206                 skb_pull(skb, 2);
1207 #else
1208                 /* for data packets, record the time */
1209                 ppp->last_xmit = jiffies;
1210 #endif /* CONFIG_PPP_FILTER */
1211         }
1212
1213         ++ppp->stats64.tx_packets;
1214         ppp->stats64.tx_bytes += skb->len - 2;
1215
1216         switch (proto) {
1217         case PPP_IP:
1218                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1219                         break;
1220                 /* try to do VJ TCP header compression */
1221                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1222                                     GFP_ATOMIC);
1223                 if (!new_skb) {
1224                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1225                         goto drop;
1226                 }
1227                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1228                 cp = skb->data + 2;
1229                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1230                                     new_skb->data + 2, &cp,
1231                                     !(ppp->flags & SC_NO_TCP_CCID));
1232                 if (cp == skb->data + 2) {
1233                         /* didn't compress */
1234                         consume_skb(new_skb);
1235                 } else {
1236                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1237                                 proto = PPP_VJC_COMP;
1238                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1239                         } else {
1240                                 proto = PPP_VJC_UNCOMP;
1241                                 cp[0] = skb->data[2];
1242                         }
1243                         consume_skb(skb);
1244                         skb = new_skb;
1245                         cp = skb_put(skb, len + 2);
1246                         cp[0] = 0;
1247                         cp[1] = proto;
1248                 }
1249                 break;
1250
1251         case PPP_CCP:
1252                 /* peek at outbound CCP frames */
1253                 ppp_ccp_peek(ppp, skb, 0);
1254                 break;
1255         }
1256
1257         /* try to do packet compression */
1258         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1259             proto != PPP_LCP && proto != PPP_CCP) {
1260                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1261                         if (net_ratelimit())
1262                                 netdev_err(ppp->dev,
1263                                            "ppp: compression required but "
1264                                            "down - pkt dropped.\n");
1265                         goto drop;
1266                 }
1267                 skb = pad_compress_skb(ppp, skb);
1268                 if (!skb)
1269                         goto drop;
1270         }
1271
1272         /*
1273          * If we are waiting for traffic (demand dialling),
1274          * queue it up for pppd to receive.
1275          */
1276         if (ppp->flags & SC_LOOP_TRAFFIC) {
1277                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1278                         goto drop;
1279                 skb_queue_tail(&ppp->file.rq, skb);
1280                 wake_up_interruptible(&ppp->file.rwait);
1281                 return;
1282         }
1283
1284         ppp->xmit_pending = skb;
1285         ppp_push(ppp);
1286         return;
1287
1288  drop:
1289         kfree_skb(skb);
1290         ++ppp->dev->stats.tx_errors;
1291 }
1292
1293 /*
1294  * Try to send the frame in xmit_pending.
1295  * The caller should have the xmit path locked.
1296  */
1297 static void
1298 ppp_push(struct ppp *ppp)
1299 {
1300         struct list_head *list;
1301         struct channel *pch;
1302         struct sk_buff *skb = ppp->xmit_pending;
1303
1304         if (!skb)
1305                 return;
1306
1307         list = &ppp->channels;
1308         if (list_empty(list)) {
1309                 /* nowhere to send the packet, just drop it */
1310                 ppp->xmit_pending = NULL;
1311                 kfree_skb(skb);
1312                 return;
1313         }
1314
1315         if ((ppp->flags & SC_MULTILINK) == 0) {
1316                 /* not doing multilink: send it down the first channel */
1317                 list = list->next;
1318                 pch = list_entry(list, struct channel, clist);
1319
1320                 spin_lock_bh(&pch->downl);
1321                 if (pch->chan) {
1322                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1323                                 ppp->xmit_pending = NULL;
1324                 } else {
1325                         /* channel got unregistered */
1326                         kfree_skb(skb);
1327                         ppp->xmit_pending = NULL;
1328                 }
1329                 spin_unlock_bh(&pch->downl);
1330                 return;
1331         }
1332
1333 #ifdef CONFIG_PPP_MULTILINK
1334         /* Multilink: fragment the packet over as many links
1335            as can take the packet at the moment. */
1336         if (!ppp_mp_explode(ppp, skb))
1337                 return;
1338 #endif /* CONFIG_PPP_MULTILINK */
1339
1340         ppp->xmit_pending = NULL;
1341         kfree_skb(skb);
1342 }
1343
1344 #ifdef CONFIG_PPP_MULTILINK
1345 static bool mp_protocol_compress __read_mostly = true;
1346 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1347 MODULE_PARM_DESC(mp_protocol_compress,
1348                  "compress protocol id in multilink fragments");
1349
1350 /*
1351  * Divide a packet to be transmitted into fragments and
1352  * send them out the individual links.
1353  */
1354 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1355 {
1356         int len, totlen;
1357         int i, bits, hdrlen, mtu;
1358         int flen;
1359         int navail, nfree, nzero;
1360         int nbigger;
1361         int totspeed;
1362         int totfree;
1363         unsigned char *p, *q;
1364         struct list_head *list;
1365         struct channel *pch;
1366         struct sk_buff *frag;
1367         struct ppp_channel *chan;
1368
1369         totspeed = 0; /*total bitrate of the bundle*/
1370         nfree = 0; /* # channels which have no packet already queued */
1371         navail = 0; /* total # of usable channels (not deregistered) */
1372         nzero = 0; /* number of channels with zero speed associated*/
1373         totfree = 0; /*total # of channels available and
1374                                   *having no queued packets before
1375                                   *starting the fragmentation*/
1376
1377         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1378         i = 0;
1379         list_for_each_entry(pch, &ppp->channels, clist) {
1380                 if (pch->chan) {
1381                         pch->avail = 1;
1382                         navail++;
1383                         pch->speed = pch->chan->speed;
1384                 } else {
1385                         pch->avail = 0;
1386                 }
1387                 if (pch->avail) {
1388                         if (skb_queue_empty(&pch->file.xq) ||
1389                                 !pch->had_frag) {
1390                                         if (pch->speed == 0)
1391                                                 nzero++;
1392                                         else
1393                                                 totspeed += pch->speed;
1394
1395                                         pch->avail = 2;
1396                                         ++nfree;
1397                                         ++totfree;
1398                                 }
1399                         if (!pch->had_frag && i < ppp->nxchan)
1400                                 ppp->nxchan = i;
1401                 }
1402                 ++i;
1403         }
1404         /*
1405          * Don't start sending this packet unless at least half of
1406          * the channels are free.  This gives much better TCP
1407          * performance if we have a lot of channels.
1408          */
1409         if (nfree == 0 || nfree < navail / 2)
1410                 return 0; /* can't take now, leave it in xmit_pending */
1411
1412         /* Do protocol field compression */
1413         p = skb->data;
1414         len = skb->len;
1415         if (*p == 0 && mp_protocol_compress) {
1416                 ++p;
1417                 --len;
1418         }
1419
1420         totlen = len;
1421         nbigger = len % nfree;
1422
1423         /* skip to the channel after the one we last used
1424            and start at that one */
1425         list = &ppp->channels;
1426         for (i = 0; i < ppp->nxchan; ++i) {
1427                 list = list->next;
1428                 if (list == &ppp->channels) {
1429                         i = 0;
1430                         break;
1431                 }
1432         }
1433
1434         /* create a fragment for each channel */
1435         bits = B;
1436         while (len > 0) {
1437                 list = list->next;
1438                 if (list == &ppp->channels) {
1439                         i = 0;
1440                         continue;
1441                 }
1442                 pch = list_entry(list, struct channel, clist);
1443                 ++i;
1444                 if (!pch->avail)
1445                         continue;
1446
1447                 /*
1448                  * Skip this channel if it has a fragment pending already and
1449                  * we haven't given a fragment to all of the free channels.
1450                  */
1451                 if (pch->avail == 1) {
1452                         if (nfree > 0)
1453                                 continue;
1454                 } else {
1455                         pch->avail = 1;
1456                 }
1457
1458                 /* check the channel's mtu and whether it is still attached. */
1459                 spin_lock_bh(&pch->downl);
1460                 if (pch->chan == NULL) {
1461                         /* can't use this channel, it's being deregistered */
1462                         if (pch->speed == 0)
1463                                 nzero--;
1464                         else
1465                                 totspeed -= pch->speed;
1466
1467                         spin_unlock_bh(&pch->downl);
1468                         pch->avail = 0;
1469                         totlen = len;
1470                         totfree--;
1471                         nfree--;
1472                         if (--navail == 0)
1473                                 break;
1474                         continue;
1475                 }
1476
1477                 /*
1478                 *if the channel speed is not set divide
1479                 *the packet evenly among the free channels;
1480                 *otherwise divide it according to the speed
1481                 *of the channel we are going to transmit on
1482                 */
1483                 flen = len;
1484                 if (nfree > 0) {
1485                         if (pch->speed == 0) {
1486                                 flen = len/nfree;
1487                                 if (nbigger > 0) {
1488                                         flen++;
1489                                         nbigger--;
1490                                 }
1491                         } else {
1492                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1493                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1494                                 if (nbigger > 0) {
1495                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1496                                         nbigger -= ((totfree - nzero)*pch->speed)/
1497                                                         totspeed;
1498                                 }
1499                         }
1500                         nfree--;
1501                 }
1502
1503                 /*
1504                  *check if we are on the last channel or
1505                  *we exceded the length of the data to
1506                  *fragment
1507                  */
1508                 if ((nfree <= 0) || (flen > len))
1509                         flen = len;
1510                 /*
1511                  *it is not worth to tx on slow channels:
1512                  *in that case from the resulting flen according to the
1513                  *above formula will be equal or less than zero.
1514                  *Skip the channel in this case
1515                  */
1516                 if (flen <= 0) {
1517                         pch->avail = 2;
1518                         spin_unlock_bh(&pch->downl);
1519                         continue;
1520                 }
1521
1522                 /*
1523                  * hdrlen includes the 2-byte PPP protocol field, but the
1524                  * MTU counts only the payload excluding the protocol field.
1525                  * (RFC1661 Section 2)
1526                  */
1527                 mtu = pch->chan->mtu - (hdrlen - 2);
1528                 if (mtu < 4)
1529                         mtu = 4;
1530                 if (flen > mtu)
1531                         flen = mtu;
1532                 if (flen == len)
1533                         bits |= E;
1534                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1535                 if (!frag)
1536                         goto noskb;
1537                 q = skb_put(frag, flen + hdrlen);
1538
1539                 /* make the MP header */
1540                 put_unaligned_be16(PPP_MP, q);
1541                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1542                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1543                         q[3] = ppp->nxseq;
1544                 } else {
1545                         q[2] = bits;
1546                         q[3] = ppp->nxseq >> 16;
1547                         q[4] = ppp->nxseq >> 8;
1548                         q[5] = ppp->nxseq;
1549                 }
1550
1551                 memcpy(q + hdrlen, p, flen);
1552
1553                 /* try to send it down the channel */
1554                 chan = pch->chan;
1555                 if (!skb_queue_empty(&pch->file.xq) ||
1556                         !chan->ops->start_xmit(chan, frag))
1557                         skb_queue_tail(&pch->file.xq, frag);
1558                 pch->had_frag = 1;
1559                 p += flen;
1560                 len -= flen;
1561                 ++ppp->nxseq;
1562                 bits = 0;
1563                 spin_unlock_bh(&pch->downl);
1564         }
1565         ppp->nxchan = i;
1566
1567         return 1;
1568
1569  noskb:
1570         spin_unlock_bh(&pch->downl);
1571         if (ppp->debug & 1)
1572                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1573         ++ppp->dev->stats.tx_errors;
1574         ++ppp->nxseq;
1575         return 1;       /* abandon the frame */
1576 }
1577 #endif /* CONFIG_PPP_MULTILINK */
1578
1579 /*
1580  * Try to send data out on a channel.
1581  */
1582 static void
1583 ppp_channel_push(struct channel *pch)
1584 {
1585         struct sk_buff *skb;
1586         struct ppp *ppp;
1587
1588         spin_lock_bh(&pch->downl);
1589         if (pch->chan) {
1590                 while (!skb_queue_empty(&pch->file.xq)) {
1591                         skb = skb_dequeue(&pch->file.xq);
1592                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1593                                 /* put the packet back and try again later */
1594                                 skb_queue_head(&pch->file.xq, skb);
1595                                 break;
1596                         }
1597                 }
1598         } else {
1599                 /* channel got deregistered */
1600                 skb_queue_purge(&pch->file.xq);
1601         }
1602         spin_unlock_bh(&pch->downl);
1603         /* see if there is anything from the attached unit to be sent */
1604         if (skb_queue_empty(&pch->file.xq)) {
1605                 read_lock_bh(&pch->upl);
1606                 ppp = pch->ppp;
1607                 if (ppp)
1608                         ppp_xmit_process(ppp);
1609                 read_unlock_bh(&pch->upl);
1610         }
1611 }
1612
1613 /*
1614  * Receive-side routines.
1615  */
1616
1617 struct ppp_mp_skb_parm {
1618         u32             sequence;
1619         u8              BEbits;
1620 };
1621 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1622
1623 static inline void
1624 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1625 {
1626         ppp_recv_lock(ppp);
1627         if (!ppp->closing)
1628                 ppp_receive_frame(ppp, skb, pch);
1629         else
1630                 kfree_skb(skb);
1631         ppp_recv_unlock(ppp);
1632 }
1633
1634 void
1635 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1636 {
1637         struct channel *pch = chan->ppp;
1638         int proto;
1639
1640         if (!pch) {
1641                 kfree_skb(skb);
1642                 return;
1643         }
1644
1645         read_lock_bh(&pch->upl);
1646         if (!pskb_may_pull(skb, 2)) {
1647                 kfree_skb(skb);
1648                 if (pch->ppp) {
1649                         ++pch->ppp->dev->stats.rx_length_errors;
1650                         ppp_receive_error(pch->ppp);
1651                 }
1652                 goto done;
1653         }
1654
1655         proto = PPP_PROTO(skb);
1656         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1657                 /* put it on the channel queue */
1658                 skb_queue_tail(&pch->file.rq, skb);
1659                 /* drop old frames if queue too long */
1660                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1661                        (skb = skb_dequeue(&pch->file.rq)))
1662                         kfree_skb(skb);
1663                 wake_up_interruptible(&pch->file.rwait);
1664         } else {
1665                 ppp_do_recv(pch->ppp, skb, pch);
1666         }
1667
1668 done:
1669         read_unlock_bh(&pch->upl);
1670 }
1671
1672 /* Put a 0-length skb in the receive queue as an error indication */
1673 void
1674 ppp_input_error(struct ppp_channel *chan, int code)
1675 {
1676         struct channel *pch = chan->ppp;
1677         struct sk_buff *skb;
1678
1679         if (!pch)
1680                 return;
1681
1682         read_lock_bh(&pch->upl);
1683         if (pch->ppp) {
1684                 skb = alloc_skb(0, GFP_ATOMIC);
1685                 if (skb) {
1686                         skb->len = 0;           /* probably unnecessary */
1687                         skb->cb[0] = code;
1688                         ppp_do_recv(pch->ppp, skb, pch);
1689                 }
1690         }
1691         read_unlock_bh(&pch->upl);
1692 }
1693
1694 /*
1695  * We come in here to process a received frame.
1696  * The receive side of the ppp unit is locked.
1697  */
1698 static void
1699 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1700 {
1701         /* note: a 0-length skb is used as an error indication */
1702         if (skb->len > 0) {
1703 #ifdef CONFIG_PPP_MULTILINK
1704                 /* XXX do channel-level decompression here */
1705                 if (PPP_PROTO(skb) == PPP_MP)
1706                         ppp_receive_mp_frame(ppp, skb, pch);
1707                 else
1708 #endif /* CONFIG_PPP_MULTILINK */
1709                         ppp_receive_nonmp_frame(ppp, skb);
1710         } else {
1711                 kfree_skb(skb);
1712                 ppp_receive_error(ppp);
1713         }
1714 }
1715
1716 static void
1717 ppp_receive_error(struct ppp *ppp)
1718 {
1719         ++ppp->dev->stats.rx_errors;
1720         if (ppp->vj)
1721                 slhc_toss(ppp->vj);
1722 }
1723
1724 static void
1725 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1726 {
1727         struct sk_buff *ns;
1728         int proto, len, npi;
1729
1730         /*
1731          * Decompress the frame, if compressed.
1732          * Note that some decompressors need to see uncompressed frames
1733          * that come in as well as compressed frames.
1734          */
1735         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1736             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1737                 skb = ppp_decompress_frame(ppp, skb);
1738
1739         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1740                 goto err;
1741
1742         proto = PPP_PROTO(skb);
1743         switch (proto) {
1744         case PPP_VJC_COMP:
1745                 /* decompress VJ compressed packets */
1746                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1747                         goto err;
1748
1749                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1750                         /* copy to a new sk_buff with more tailroom */
1751                         ns = dev_alloc_skb(skb->len + 128);
1752                         if (!ns) {
1753                                 netdev_err(ppp->dev, "PPP: no memory "
1754                                            "(VJ decomp)\n");
1755                                 goto err;
1756                         }
1757                         skb_reserve(ns, 2);
1758                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1759                         consume_skb(skb);
1760                         skb = ns;
1761                 }
1762                 else
1763                         skb->ip_summed = CHECKSUM_NONE;
1764
1765                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1766                 if (len <= 0) {
1767                         netdev_printk(KERN_DEBUG, ppp->dev,
1768                                       "PPP: VJ decompression error\n");
1769                         goto err;
1770                 }
1771                 len += 2;
1772                 if (len > skb->len)
1773                         skb_put(skb, len - skb->len);
1774                 else if (len < skb->len)
1775                         skb_trim(skb, len);
1776                 proto = PPP_IP;
1777                 break;
1778
1779         case PPP_VJC_UNCOMP:
1780                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1781                         goto err;
1782
1783                 /* Until we fix the decompressor need to make sure
1784                  * data portion is linear.
1785                  */
1786                 if (!pskb_may_pull(skb, skb->len))
1787                         goto err;
1788
1789                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1790                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1791                         goto err;
1792                 }
1793                 proto = PPP_IP;
1794                 break;
1795
1796         case PPP_CCP:
1797                 ppp_ccp_peek(ppp, skb, 1);
1798                 break;
1799         }
1800
1801         ++ppp->stats64.rx_packets;
1802         ppp->stats64.rx_bytes += skb->len - 2;
1803
1804         npi = proto_to_npindex(proto);
1805         if (npi < 0) {
1806                 /* control or unknown frame - pass it to pppd */
1807                 skb_queue_tail(&ppp->file.rq, skb);
1808                 /* limit queue length by dropping old frames */
1809                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1810                        (skb = skb_dequeue(&ppp->file.rq)))
1811                         kfree_skb(skb);
1812                 /* wake up any process polling or blocking on read */
1813                 wake_up_interruptible(&ppp->file.rwait);
1814
1815         } else {
1816                 /* network protocol frame - give it to the kernel */
1817
1818 #ifdef CONFIG_PPP_FILTER
1819                 /* check if the packet passes the pass and active filters */
1820                 /* the filter instructions are constructed assuming
1821                    a four-byte PPP header on each packet */
1822                 if (ppp->pass_filter || ppp->active_filter) {
1823                         if (skb_unclone(skb, GFP_ATOMIC))
1824                                 goto err;
1825
1826                         *skb_push(skb, 2) = 0;
1827                         if (ppp->pass_filter &&
1828                             SK_RUN_FILTER(ppp->pass_filter, skb) == 0) {
1829                                 if (ppp->debug & 1)
1830                                         netdev_printk(KERN_DEBUG, ppp->dev,
1831                                                       "PPP: inbound frame "
1832                                                       "not passed\n");
1833                                 kfree_skb(skb);
1834                                 return;
1835                         }
1836                         if (!(ppp->active_filter &&
1837                               SK_RUN_FILTER(ppp->active_filter, skb) == 0))
1838                                 ppp->last_recv = jiffies;
1839                         __skb_pull(skb, 2);
1840                 } else
1841 #endif /* CONFIG_PPP_FILTER */
1842                         ppp->last_recv = jiffies;
1843
1844                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1845                     ppp->npmode[npi] != NPMODE_PASS) {
1846                         kfree_skb(skb);
1847                 } else {
1848                         /* chop off protocol */
1849                         skb_pull_rcsum(skb, 2);
1850                         skb->dev = ppp->dev;
1851                         skb->protocol = htons(npindex_to_ethertype[npi]);
1852                         skb_reset_mac_header(skb);
1853                         netif_rx(skb);
1854                 }
1855         }
1856         return;
1857
1858  err:
1859         kfree_skb(skb);
1860         ppp_receive_error(ppp);
1861 }
1862
1863 static struct sk_buff *
1864 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1865 {
1866         int proto = PPP_PROTO(skb);
1867         struct sk_buff *ns;
1868         int len;
1869
1870         /* Until we fix all the decompressor's need to make sure
1871          * data portion is linear.
1872          */
1873         if (!pskb_may_pull(skb, skb->len))
1874                 goto err;
1875
1876         if (proto == PPP_COMP) {
1877                 int obuff_size;
1878
1879                 switch(ppp->rcomp->compress_proto) {
1880                 case CI_MPPE:
1881                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1882                         break;
1883                 default:
1884                         obuff_size = ppp->mru + PPP_HDRLEN;
1885                         break;
1886                 }
1887
1888                 ns = dev_alloc_skb(obuff_size);
1889                 if (!ns) {
1890                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1891                                    "no memory\n");
1892                         goto err;
1893                 }
1894                 /* the decompressor still expects the A/C bytes in the hdr */
1895                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1896                                 skb->len + 2, ns->data, obuff_size);
1897                 if (len < 0) {
1898                         /* Pass the compressed frame to pppd as an
1899                            error indication. */
1900                         if (len == DECOMP_FATALERROR)
1901                                 ppp->rstate |= SC_DC_FERROR;
1902                         kfree_skb(ns);
1903                         goto err;
1904                 }
1905
1906                 consume_skb(skb);
1907                 skb = ns;
1908                 skb_put(skb, len);
1909                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1910
1911         } else {
1912                 /* Uncompressed frame - pass to decompressor so it
1913                    can update its dictionary if necessary. */
1914                 if (ppp->rcomp->incomp)
1915                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1916                                            skb->len + 2);
1917         }
1918
1919         return skb;
1920
1921  err:
1922         ppp->rstate |= SC_DC_ERROR;
1923         ppp_receive_error(ppp);
1924         return skb;
1925 }
1926
1927 #ifdef CONFIG_PPP_MULTILINK
1928 /*
1929  * Receive a multilink frame.
1930  * We put it on the reconstruction queue and then pull off
1931  * as many completed frames as we can.
1932  */
1933 static void
1934 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1935 {
1936         u32 mask, seq;
1937         struct channel *ch;
1938         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1939
1940         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1941                 goto err;               /* no good, throw it away */
1942
1943         /* Decode sequence number and begin/end bits */
1944         if (ppp->flags & SC_MP_SHORTSEQ) {
1945                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1946                 mask = 0xfff;
1947         } else {
1948                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1949                 mask = 0xffffff;
1950         }
1951         PPP_MP_CB(skb)->BEbits = skb->data[2];
1952         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1953
1954         /*
1955          * Do protocol ID decompression on the first fragment of each packet.
1956          */
1957         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
1958                 *skb_push(skb, 1) = 0;
1959
1960         /*
1961          * Expand sequence number to 32 bits, making it as close
1962          * as possible to ppp->minseq.
1963          */
1964         seq |= ppp->minseq & ~mask;
1965         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1966                 seq += mask + 1;
1967         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1968                 seq -= mask + 1;        /* should never happen */
1969         PPP_MP_CB(skb)->sequence = seq;
1970         pch->lastseq = seq;
1971
1972         /*
1973          * If this packet comes before the next one we were expecting,
1974          * drop it.
1975          */
1976         if (seq_before(seq, ppp->nextseq)) {
1977                 kfree_skb(skb);
1978                 ++ppp->dev->stats.rx_dropped;
1979                 ppp_receive_error(ppp);
1980                 return;
1981         }
1982
1983         /*
1984          * Reevaluate minseq, the minimum over all channels of the
1985          * last sequence number received on each channel.  Because of
1986          * the increasing sequence number rule, we know that any fragment
1987          * before `minseq' which hasn't arrived is never going to arrive.
1988          * The list of channels can't change because we have the receive
1989          * side of the ppp unit locked.
1990          */
1991         list_for_each_entry(ch, &ppp->channels, clist) {
1992                 if (seq_before(ch->lastseq, seq))
1993                         seq = ch->lastseq;
1994         }
1995         if (seq_before(ppp->minseq, seq))
1996                 ppp->minseq = seq;
1997
1998         /* Put the fragment on the reconstruction queue */
1999         ppp_mp_insert(ppp, skb);
2000
2001         /* If the queue is getting long, don't wait any longer for packets
2002            before the start of the queue. */
2003         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2004                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2005                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2006                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2007         }
2008
2009         /* Pull completed packets off the queue and receive them. */
2010         while ((skb = ppp_mp_reconstruct(ppp))) {
2011                 if (pskb_may_pull(skb, 2))
2012                         ppp_receive_nonmp_frame(ppp, skb);
2013                 else {
2014                         ++ppp->dev->stats.rx_length_errors;
2015                         kfree_skb(skb);
2016                         ppp_receive_error(ppp);
2017                 }
2018         }
2019
2020         return;
2021
2022  err:
2023         kfree_skb(skb);
2024         ppp_receive_error(ppp);
2025 }
2026
2027 /*
2028  * Insert a fragment on the MP reconstruction queue.
2029  * The queue is ordered by increasing sequence number.
2030  */
2031 static void
2032 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2033 {
2034         struct sk_buff *p;
2035         struct sk_buff_head *list = &ppp->mrq;
2036         u32 seq = PPP_MP_CB(skb)->sequence;
2037
2038         /* N.B. we don't need to lock the list lock because we have the
2039            ppp unit receive-side lock. */
2040         skb_queue_walk(list, p) {
2041                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2042                         break;
2043         }
2044         __skb_queue_before(list, p, skb);
2045 }
2046
2047 /*
2048  * Reconstruct a packet from the MP fragment queue.
2049  * We go through increasing sequence numbers until we find a
2050  * complete packet, or we get to the sequence number for a fragment
2051  * which hasn't arrived but might still do so.
2052  */
2053 static struct sk_buff *
2054 ppp_mp_reconstruct(struct ppp *ppp)
2055 {
2056         u32 seq = ppp->nextseq;
2057         u32 minseq = ppp->minseq;
2058         struct sk_buff_head *list = &ppp->mrq;
2059         struct sk_buff *p, *tmp;
2060         struct sk_buff *head, *tail;
2061         struct sk_buff *skb = NULL;
2062         int lost = 0, len = 0;
2063
2064         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2065                 return NULL;
2066         head = list->next;
2067         tail = NULL;
2068         skb_queue_walk_safe(list, p, tmp) {
2069         again:
2070                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2071                         /* this can't happen, anyway ignore the skb */
2072                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2073                                    "seq %u < %u\n",
2074                                    PPP_MP_CB(p)->sequence, seq);
2075                         __skb_unlink(p, list);
2076                         kfree_skb(p);
2077                         continue;
2078                 }
2079                 if (PPP_MP_CB(p)->sequence != seq) {
2080                         u32 oldseq;
2081                         /* Fragment `seq' is missing.  If it is after
2082                            minseq, it might arrive later, so stop here. */
2083                         if (seq_after(seq, minseq))
2084                                 break;
2085                         /* Fragment `seq' is lost, keep going. */
2086                         lost = 1;
2087                         oldseq = seq;
2088                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2089                                 minseq + 1: PPP_MP_CB(p)->sequence;
2090
2091                         if (ppp->debug & 1)
2092                                 netdev_printk(KERN_DEBUG, ppp->dev,
2093                                               "lost frag %u..%u\n",
2094                                               oldseq, seq-1);
2095
2096                         goto again;
2097                 }
2098
2099                 /*
2100                  * At this point we know that all the fragments from
2101                  * ppp->nextseq to seq are either present or lost.
2102                  * Also, there are no complete packets in the queue
2103                  * that have no missing fragments and end before this
2104                  * fragment.
2105                  */
2106
2107                 /* B bit set indicates this fragment starts a packet */
2108                 if (PPP_MP_CB(p)->BEbits & B) {
2109                         head = p;
2110                         lost = 0;
2111                         len = 0;
2112                 }
2113
2114                 len += p->len;
2115
2116                 /* Got a complete packet yet? */
2117                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2118                     (PPP_MP_CB(head)->BEbits & B)) {
2119                         if (len > ppp->mrru + 2) {
2120                                 ++ppp->dev->stats.rx_length_errors;
2121                                 netdev_printk(KERN_DEBUG, ppp->dev,
2122                                               "PPP: reconstructed packet"
2123                                               " is too long (%d)\n", len);
2124                         } else {
2125                                 tail = p;
2126                                 break;
2127                         }
2128                         ppp->nextseq = seq + 1;
2129                 }
2130
2131                 /*
2132                  * If this is the ending fragment of a packet,
2133                  * and we haven't found a complete valid packet yet,
2134                  * we can discard up to and including this fragment.
2135                  */
2136                 if (PPP_MP_CB(p)->BEbits & E) {
2137                         struct sk_buff *tmp2;
2138
2139                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2140                                 if (ppp->debug & 1)
2141                                         netdev_printk(KERN_DEBUG, ppp->dev,
2142                                                       "discarding frag %u\n",
2143                                                       PPP_MP_CB(p)->sequence);
2144                                 __skb_unlink(p, list);
2145                                 kfree_skb(p);
2146                         }
2147                         head = skb_peek(list);
2148                         if (!head)
2149                                 break;
2150                 }
2151                 ++seq;
2152         }
2153
2154         /* If we have a complete packet, copy it all into one skb. */
2155         if (tail != NULL) {
2156                 /* If we have discarded any fragments,
2157                    signal a receive error. */
2158                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2159                         skb_queue_walk_safe(list, p, tmp) {
2160                                 if (p == head)
2161                                         break;
2162                                 if (ppp->debug & 1)
2163                                         netdev_printk(KERN_DEBUG, ppp->dev,
2164                                                       "discarding frag %u\n",
2165                                                       PPP_MP_CB(p)->sequence);
2166                                 __skb_unlink(p, list);
2167                                 kfree_skb(p);
2168                         }
2169
2170                         if (ppp->debug & 1)
2171                                 netdev_printk(KERN_DEBUG, ppp->dev,
2172                                               "  missed pkts %u..%u\n",
2173                                               ppp->nextseq,
2174                                               PPP_MP_CB(head)->sequence-1);
2175                         ++ppp->dev->stats.rx_dropped;
2176                         ppp_receive_error(ppp);
2177                 }
2178
2179                 skb = head;
2180                 if (head != tail) {
2181                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2182                         p = skb_queue_next(list, head);
2183                         __skb_unlink(skb, list);
2184                         skb_queue_walk_from_safe(list, p, tmp) {
2185                                 __skb_unlink(p, list);
2186                                 *fragpp = p;
2187                                 p->next = NULL;
2188                                 fragpp = &p->next;
2189
2190                                 skb->len += p->len;
2191                                 skb->data_len += p->len;
2192                                 skb->truesize += p->truesize;
2193
2194                                 if (p == tail)
2195                                         break;
2196                         }
2197                 } else {
2198                         __skb_unlink(skb, list);
2199                 }
2200
2201                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2202         }
2203
2204         return skb;
2205 }
2206 #endif /* CONFIG_PPP_MULTILINK */
2207
2208 /*
2209  * Channel interface.
2210  */
2211
2212 /* Create a new, unattached ppp channel. */
2213 int ppp_register_channel(struct ppp_channel *chan)
2214 {
2215         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2216 }
2217
2218 /* Create a new, unattached ppp channel for specified net. */
2219 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2220 {
2221         struct channel *pch;
2222         struct ppp_net *pn;
2223
2224         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2225         if (!pch)
2226                 return -ENOMEM;
2227
2228         pn = ppp_pernet(net);
2229
2230         pch->ppp = NULL;
2231         pch->chan = chan;
2232         pch->chan_net = net;
2233         chan->ppp = pch;
2234         init_ppp_file(&pch->file, CHANNEL);
2235         pch->file.hdrlen = chan->hdrlen;
2236 #ifdef CONFIG_PPP_MULTILINK
2237         pch->lastseq = -1;
2238 #endif /* CONFIG_PPP_MULTILINK */
2239         init_rwsem(&pch->chan_sem);
2240         spin_lock_init(&pch->downl);
2241         rwlock_init(&pch->upl);
2242
2243         spin_lock_bh(&pn->all_channels_lock);
2244         pch->file.index = ++pn->last_channel_index;
2245         list_add(&pch->list, &pn->new_channels);
2246         atomic_inc(&channel_count);
2247         spin_unlock_bh(&pn->all_channels_lock);
2248
2249         return 0;
2250 }
2251
2252 /*
2253  * Return the index of a channel.
2254  */
2255 int ppp_channel_index(struct ppp_channel *chan)
2256 {
2257         struct channel *pch = chan->ppp;
2258
2259         if (pch)
2260                 return pch->file.index;
2261         return -1;
2262 }
2263
2264 /*
2265  * Return the PPP unit number to which a channel is connected.
2266  */
2267 int ppp_unit_number(struct ppp_channel *chan)
2268 {
2269         struct channel *pch = chan->ppp;
2270         int unit = -1;
2271
2272         if (pch) {
2273                 read_lock_bh(&pch->upl);
2274                 if (pch->ppp)
2275                         unit = pch->ppp->file.index;
2276                 read_unlock_bh(&pch->upl);
2277         }
2278         return unit;
2279 }
2280
2281 /*
2282  * Return the PPP device interface name of a channel.
2283  */
2284 char *ppp_dev_name(struct ppp_channel *chan)
2285 {
2286         struct channel *pch = chan->ppp;
2287         char *name = NULL;
2288
2289         if (pch) {
2290                 read_lock_bh(&pch->upl);
2291                 if (pch->ppp && pch->ppp->dev)
2292                         name = pch->ppp->dev->name;
2293                 read_unlock_bh(&pch->upl);
2294         }
2295         return name;
2296 }
2297
2298
2299 /*
2300  * Disconnect a channel from the generic layer.
2301  * This must be called in process context.
2302  */
2303 void
2304 ppp_unregister_channel(struct ppp_channel *chan)
2305 {
2306         struct channel *pch = chan->ppp;
2307         struct ppp_net *pn;
2308
2309         if (!pch)
2310                 return;         /* should never happen */
2311
2312         chan->ppp = NULL;
2313
2314         /*
2315          * This ensures that we have returned from any calls into the
2316          * the channel's start_xmit or ioctl routine before we proceed.
2317          */
2318         down_write(&pch->chan_sem);
2319         spin_lock_bh(&pch->downl);
2320         pch->chan = NULL;
2321         spin_unlock_bh(&pch->downl);
2322         up_write(&pch->chan_sem);
2323         ppp_disconnect_channel(pch);
2324
2325         pn = ppp_pernet(pch->chan_net);
2326         spin_lock_bh(&pn->all_channels_lock);
2327         list_del(&pch->list);
2328         spin_unlock_bh(&pn->all_channels_lock);
2329
2330         pch->file.dead = 1;
2331         wake_up_interruptible(&pch->file.rwait);
2332         if (atomic_dec_and_test(&pch->file.refcnt))
2333                 ppp_destroy_channel(pch);
2334 }
2335
2336 /*
2337  * Callback from a channel when it can accept more to transmit.
2338  * This should be called at BH/softirq level, not interrupt level.
2339  */
2340 void
2341 ppp_output_wakeup(struct ppp_channel *chan)
2342 {
2343         struct channel *pch = chan->ppp;
2344
2345         if (!pch)
2346                 return;
2347         ppp_channel_push(pch);
2348 }
2349
2350 /*
2351  * Compression control.
2352  */
2353
2354 /* Process the PPPIOCSCOMPRESS ioctl. */
2355 static int
2356 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2357 {
2358         int err;
2359         struct compressor *cp, *ocomp;
2360         struct ppp_option_data data;
2361         void *state, *ostate;
2362         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2363
2364         err = -EFAULT;
2365         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2366             (data.length <= CCP_MAX_OPTION_LENGTH &&
2367              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2368                 goto out;
2369         err = -EINVAL;
2370         if (data.length > CCP_MAX_OPTION_LENGTH ||
2371             ccp_option[1] < 2 || ccp_option[1] > data.length)
2372                 goto out;
2373
2374         cp = try_then_request_module(
2375                 find_compressor(ccp_option[0]),
2376                 "ppp-compress-%d", ccp_option[0]);
2377         if (!cp)
2378                 goto out;
2379
2380         err = -ENOBUFS;
2381         if (data.transmit) {
2382                 state = cp->comp_alloc(ccp_option, data.length);
2383                 if (state) {
2384                         ppp_xmit_lock(ppp);
2385                         ppp->xstate &= ~SC_COMP_RUN;
2386                         ocomp = ppp->xcomp;
2387                         ostate = ppp->xc_state;
2388                         ppp->xcomp = cp;
2389                         ppp->xc_state = state;
2390                         ppp_xmit_unlock(ppp);
2391                         if (ostate) {
2392                                 ocomp->comp_free(ostate);
2393                                 module_put(ocomp->owner);
2394                         }
2395                         err = 0;
2396                 } else
2397                         module_put(cp->owner);
2398
2399         } else {
2400                 state = cp->decomp_alloc(ccp_option, data.length);
2401                 if (state) {
2402                         ppp_recv_lock(ppp);
2403                         ppp->rstate &= ~SC_DECOMP_RUN;
2404                         ocomp = ppp->rcomp;
2405                         ostate = ppp->rc_state;
2406                         ppp->rcomp = cp;
2407                         ppp->rc_state = state;
2408                         ppp_recv_unlock(ppp);
2409                         if (ostate) {
2410                                 ocomp->decomp_free(ostate);
2411                                 module_put(ocomp->owner);
2412                         }
2413                         err = 0;
2414                 } else
2415                         module_put(cp->owner);
2416         }
2417
2418  out:
2419         return err;
2420 }
2421
2422 /*
2423  * Look at a CCP packet and update our state accordingly.
2424  * We assume the caller has the xmit or recv path locked.
2425  */
2426 static void
2427 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2428 {
2429         unsigned char *dp;
2430         int len;
2431
2432         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2433                 return; /* no header */
2434         dp = skb->data + 2;
2435
2436         switch (CCP_CODE(dp)) {
2437         case CCP_CONFREQ:
2438
2439                 /* A ConfReq starts negotiation of compression
2440                  * in one direction of transmission,
2441                  * and hence brings it down...but which way?
2442                  *
2443                  * Remember:
2444                  * A ConfReq indicates what the sender would like to receive
2445                  */
2446                 if(inbound)
2447                         /* He is proposing what I should send */
2448                         ppp->xstate &= ~SC_COMP_RUN;
2449                 else
2450                         /* I am proposing to what he should send */
2451                         ppp->rstate &= ~SC_DECOMP_RUN;
2452
2453                 break;
2454
2455         case CCP_TERMREQ:
2456         case CCP_TERMACK:
2457                 /*
2458                  * CCP is going down, both directions of transmission
2459                  */
2460                 ppp->rstate &= ~SC_DECOMP_RUN;
2461                 ppp->xstate &= ~SC_COMP_RUN;
2462                 break;
2463
2464         case CCP_CONFACK:
2465                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2466                         break;
2467                 len = CCP_LENGTH(dp);
2468                 if (!pskb_may_pull(skb, len + 2))
2469                         return;         /* too short */
2470                 dp += CCP_HDRLEN;
2471                 len -= CCP_HDRLEN;
2472                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2473                         break;
2474                 if (inbound) {
2475                         /* we will start receiving compressed packets */
2476                         if (!ppp->rc_state)
2477                                 break;
2478                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2479                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2480                                 ppp->rstate |= SC_DECOMP_RUN;
2481                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2482                         }
2483                 } else {
2484                         /* we will soon start sending compressed packets */
2485                         if (!ppp->xc_state)
2486                                 break;
2487                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2488                                         ppp->file.index, 0, ppp->debug))
2489                                 ppp->xstate |= SC_COMP_RUN;
2490                 }
2491                 break;
2492
2493         case CCP_RESETACK:
2494                 /* reset the [de]compressor */
2495                 if ((ppp->flags & SC_CCP_UP) == 0)
2496                         break;
2497                 if (inbound) {
2498                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2499                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2500                                 ppp->rstate &= ~SC_DC_ERROR;
2501                         }
2502                 } else {
2503                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2504                                 ppp->xcomp->comp_reset(ppp->xc_state);
2505                 }
2506                 break;
2507         }
2508 }
2509
2510 /* Free up compression resources. */
2511 static void
2512 ppp_ccp_closed(struct ppp *ppp)
2513 {
2514         void *xstate, *rstate;
2515         struct compressor *xcomp, *rcomp;
2516
2517         ppp_lock(ppp);
2518         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2519         ppp->xstate = 0;
2520         xcomp = ppp->xcomp;
2521         xstate = ppp->xc_state;
2522         ppp->xc_state = NULL;
2523         ppp->rstate = 0;
2524         rcomp = ppp->rcomp;
2525         rstate = ppp->rc_state;
2526         ppp->rc_state = NULL;
2527         ppp_unlock(ppp);
2528
2529         if (xstate) {
2530                 xcomp->comp_free(xstate);
2531                 module_put(xcomp->owner);
2532         }
2533         if (rstate) {
2534                 rcomp->decomp_free(rstate);
2535                 module_put(rcomp->owner);
2536         }
2537 }
2538
2539 /* List of compressors. */
2540 static LIST_HEAD(compressor_list);
2541 static DEFINE_SPINLOCK(compressor_list_lock);
2542
2543 struct compressor_entry {
2544         struct list_head list;
2545         struct compressor *comp;
2546 };
2547
2548 static struct compressor_entry *
2549 find_comp_entry(int proto)
2550 {
2551         struct compressor_entry *ce;
2552
2553         list_for_each_entry(ce, &compressor_list, list) {
2554                 if (ce->comp->compress_proto == proto)
2555                         return ce;
2556         }
2557         return NULL;
2558 }
2559
2560 /* Register a compressor */
2561 int
2562 ppp_register_compressor(struct compressor *cp)
2563 {
2564         struct compressor_entry *ce;
2565         int ret;
2566         spin_lock(&compressor_list_lock);
2567         ret = -EEXIST;
2568         if (find_comp_entry(cp->compress_proto))
2569                 goto out;
2570         ret = -ENOMEM;
2571         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2572         if (!ce)
2573                 goto out;
2574         ret = 0;
2575         ce->comp = cp;
2576         list_add(&ce->list, &compressor_list);
2577  out:
2578         spin_unlock(&compressor_list_lock);
2579         return ret;
2580 }
2581
2582 /* Unregister a compressor */
2583 void
2584 ppp_unregister_compressor(struct compressor *cp)
2585 {
2586         struct compressor_entry *ce;
2587
2588         spin_lock(&compressor_list_lock);
2589         ce = find_comp_entry(cp->compress_proto);
2590         if (ce && ce->comp == cp) {
2591                 list_del(&ce->list);
2592                 kfree(ce);
2593         }
2594         spin_unlock(&compressor_list_lock);
2595 }
2596
2597 /* Find a compressor. */
2598 static struct compressor *
2599 find_compressor(int type)
2600 {
2601         struct compressor_entry *ce;
2602         struct compressor *cp = NULL;
2603
2604         spin_lock(&compressor_list_lock);
2605         ce = find_comp_entry(type);
2606         if (ce) {
2607                 cp = ce->comp;
2608                 if (!try_module_get(cp->owner))
2609                         cp = NULL;
2610         }
2611         spin_unlock(&compressor_list_lock);
2612         return cp;
2613 }
2614
2615 /*
2616  * Miscelleneous stuff.
2617  */
2618
2619 static void
2620 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2621 {
2622         struct slcompress *vj = ppp->vj;
2623
2624         memset(st, 0, sizeof(*st));
2625         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2626         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2627         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2628         st->p.ppp_opackets = ppp->stats64.tx_packets;
2629         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2630         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2631         if (!vj)
2632                 return;
2633         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2634         st->vj.vjs_compressed = vj->sls_o_compressed;
2635         st->vj.vjs_searches = vj->sls_o_searches;
2636         st->vj.vjs_misses = vj->sls_o_misses;
2637         st->vj.vjs_errorin = vj->sls_i_error;
2638         st->vj.vjs_tossed = vj->sls_i_tossed;
2639         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2640         st->vj.vjs_compressedin = vj->sls_i_compressed;
2641 }
2642
2643 /*
2644  * Stuff for handling the lists of ppp units and channels
2645  * and for initialization.
2646  */
2647
2648 /*
2649  * Create a new ppp interface unit.  Fails if it can't allocate memory
2650  * or if there is already a unit with the requested number.
2651  * unit == -1 means allocate a new number.
2652  */
2653 static struct ppp *
2654 ppp_create_interface(struct net *net, int unit, int *retp)
2655 {
2656         struct ppp *ppp;
2657         struct ppp_net *pn;
2658         struct net_device *dev = NULL;
2659         int ret = -ENOMEM;
2660         int i;
2661
2662         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2663         if (!dev)
2664                 goto out1;
2665
2666         pn = ppp_pernet(net);
2667
2668         ppp = netdev_priv(dev);
2669         ppp->dev = dev;
2670         ppp->mru = PPP_MRU;
2671         init_ppp_file(&ppp->file, INTERFACE);
2672         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2673         for (i = 0; i < NUM_NP; ++i)
2674                 ppp->npmode[i] = NPMODE_PASS;
2675         INIT_LIST_HEAD(&ppp->channels);
2676         spin_lock_init(&ppp->rlock);
2677         spin_lock_init(&ppp->wlock);
2678 #ifdef CONFIG_PPP_MULTILINK
2679         ppp->minseq = -1;
2680         skb_queue_head_init(&ppp->mrq);
2681 #endif /* CONFIG_PPP_MULTILINK */
2682 #ifdef CONFIG_PPP_FILTER
2683         ppp->pass_filter = NULL;
2684         ppp->active_filter = NULL;
2685 #endif /* CONFIG_PPP_FILTER */
2686
2687         /*
2688          * drum roll: don't forget to set
2689          * the net device is belong to
2690          */
2691         dev_net_set(dev, net);
2692
2693         mutex_lock(&pn->all_ppp_mutex);
2694
2695         if (unit < 0) {
2696                 unit = unit_get(&pn->units_idr, ppp);
2697                 if (unit < 0) {
2698                         ret = unit;
2699                         goto out2;
2700                 }
2701         } else {
2702                 ret = -EEXIST;
2703                 if (unit_find(&pn->units_idr, unit))
2704                         goto out2; /* unit already exists */
2705                 /*
2706                  * if caller need a specified unit number
2707                  * lets try to satisfy him, otherwise --
2708                  * he should better ask us for new unit number
2709                  *
2710                  * NOTE: yes I know that returning EEXIST it's not
2711                  * fair but at least pppd will ask us to allocate
2712                  * new unit in this case so user is happy :)
2713                  */
2714                 unit = unit_set(&pn->units_idr, ppp, unit);
2715                 if (unit < 0)
2716                         goto out2;
2717         }
2718
2719         /* Initialize the new ppp unit */
2720         ppp->file.index = unit;
2721         sprintf(dev->name, "ppp%d", unit);
2722
2723         ret = register_netdev(dev);
2724         if (ret != 0) {
2725                 unit_put(&pn->units_idr, unit);
2726                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2727                            dev->name, ret);
2728                 goto out2;
2729         }
2730
2731         ppp->ppp_net = net;
2732
2733         atomic_inc(&ppp_unit_count);
2734         mutex_unlock(&pn->all_ppp_mutex);
2735
2736         *retp = 0;
2737         return ppp;
2738
2739 out2:
2740         mutex_unlock(&pn->all_ppp_mutex);
2741         free_netdev(dev);
2742 out1:
2743         *retp = ret;
2744         return NULL;
2745 }
2746
2747 /*
2748  * Initialize a ppp_file structure.
2749  */
2750 static void
2751 init_ppp_file(struct ppp_file *pf, int kind)
2752 {
2753         pf->kind = kind;
2754         skb_queue_head_init(&pf->xq);
2755         skb_queue_head_init(&pf->rq);
2756         atomic_set(&pf->refcnt, 1);
2757         init_waitqueue_head(&pf->rwait);
2758 }
2759
2760 /*
2761  * Take down a ppp interface unit - called when the owning file
2762  * (the one that created the unit) is closed or detached.
2763  */
2764 static void ppp_shutdown_interface(struct ppp *ppp)
2765 {
2766         struct ppp_net *pn;
2767
2768         pn = ppp_pernet(ppp->ppp_net);
2769         mutex_lock(&pn->all_ppp_mutex);
2770
2771         /* This will call dev_close() for us. */
2772         ppp_lock(ppp);
2773         if (!ppp->closing) {
2774                 ppp->closing = 1;
2775                 ppp_unlock(ppp);
2776                 unregister_netdev(ppp->dev);
2777                 unit_put(&pn->units_idr, ppp->file.index);
2778         } else
2779                 ppp_unlock(ppp);
2780
2781         ppp->file.dead = 1;
2782         ppp->owner = NULL;
2783         wake_up_interruptible(&ppp->file.rwait);
2784
2785         mutex_unlock(&pn->all_ppp_mutex);
2786 }
2787
2788 /*
2789  * Free the memory used by a ppp unit.  This is only called once
2790  * there are no channels connected to the unit and no file structs
2791  * that reference the unit.
2792  */
2793 static void ppp_destroy_interface(struct ppp *ppp)
2794 {
2795         atomic_dec(&ppp_unit_count);
2796
2797         if (!ppp->file.dead || ppp->n_channels) {
2798                 /* "can't happen" */
2799                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2800                            "but dead=%d n_channels=%d !\n",
2801                            ppp, ppp->file.dead, ppp->n_channels);
2802                 return;
2803         }
2804
2805         ppp_ccp_closed(ppp);
2806         if (ppp->vj) {
2807                 slhc_free(ppp->vj);
2808                 ppp->vj = NULL;
2809         }
2810         skb_queue_purge(&ppp->file.xq);
2811         skb_queue_purge(&ppp->file.rq);
2812 #ifdef CONFIG_PPP_MULTILINK
2813         skb_queue_purge(&ppp->mrq);
2814 #endif /* CONFIG_PPP_MULTILINK */
2815 #ifdef CONFIG_PPP_FILTER
2816         if (ppp->pass_filter) {
2817                 sk_unattached_filter_destroy(ppp->pass_filter);
2818                 ppp->pass_filter = NULL;
2819         }
2820
2821         if (ppp->active_filter) {
2822                 sk_unattached_filter_destroy(ppp->active_filter);
2823                 ppp->active_filter = NULL;
2824         }
2825 #endif /* CONFIG_PPP_FILTER */
2826
2827         kfree_skb(ppp->xmit_pending);
2828
2829         free_netdev(ppp->dev);
2830 }
2831
2832 /*
2833  * Locate an existing ppp unit.
2834  * The caller should have locked the all_ppp_mutex.
2835  */
2836 static struct ppp *
2837 ppp_find_unit(struct ppp_net *pn, int unit)
2838 {
2839         return unit_find(&pn->units_idr, unit);
2840 }
2841
2842 /*
2843  * Locate an existing ppp channel.
2844  * The caller should have locked the all_channels_lock.
2845  * First we look in the new_channels list, then in the
2846  * all_channels list.  If found in the new_channels list,
2847  * we move it to the all_channels list.  This is for speed
2848  * when we have a lot of channels in use.
2849  */
2850 static struct channel *
2851 ppp_find_channel(struct ppp_net *pn, int unit)
2852 {
2853         struct channel *pch;
2854
2855         list_for_each_entry(pch, &pn->new_channels, list) {
2856                 if (pch->file.index == unit) {
2857                         list_move(&pch->list, &pn->all_channels);
2858                         return pch;
2859                 }
2860         }
2861
2862         list_for_each_entry(pch, &pn->all_channels, list) {
2863                 if (pch->file.index == unit)
2864                         return pch;
2865         }
2866
2867         return NULL;
2868 }
2869
2870 /*
2871  * Connect a PPP channel to a PPP interface unit.
2872  */
2873 static int
2874 ppp_connect_channel(struct channel *pch, int unit)
2875 {
2876         struct ppp *ppp;
2877         struct ppp_net *pn;
2878         int ret = -ENXIO;
2879         int hdrlen;
2880
2881         pn = ppp_pernet(pch->chan_net);
2882
2883         mutex_lock(&pn->all_ppp_mutex);
2884         ppp = ppp_find_unit(pn, unit);
2885         if (!ppp)
2886                 goto out;
2887         write_lock_bh(&pch->upl);
2888         ret = -EINVAL;
2889         if (pch->ppp)
2890                 goto outl;
2891
2892         ppp_lock(ppp);
2893         if (pch->file.hdrlen > ppp->file.hdrlen)
2894                 ppp->file.hdrlen = pch->file.hdrlen;
2895         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2896         if (hdrlen > ppp->dev->hard_header_len)
2897                 ppp->dev->hard_header_len = hdrlen;
2898         list_add_tail(&pch->clist, &ppp->channels);
2899         ++ppp->n_channels;
2900         pch->ppp = ppp;
2901         atomic_inc(&ppp->file.refcnt);
2902         ppp_unlock(ppp);
2903         ret = 0;
2904
2905  outl:
2906         write_unlock_bh(&pch->upl);
2907  out:
2908         mutex_unlock(&pn->all_ppp_mutex);
2909         return ret;
2910 }
2911
2912 /*
2913  * Disconnect a channel from its ppp unit.
2914  */
2915 static int
2916 ppp_disconnect_channel(struct channel *pch)
2917 {
2918         struct ppp *ppp;
2919         int err = -EINVAL;
2920
2921         write_lock_bh(&pch->upl);
2922         ppp = pch->ppp;
2923         pch->ppp = NULL;
2924         write_unlock_bh(&pch->upl);
2925         if (ppp) {
2926                 /* remove it from the ppp unit's list */
2927                 ppp_lock(ppp);
2928                 list_del(&pch->clist);
2929                 if (--ppp->n_channels == 0)
2930                         wake_up_interruptible(&ppp->file.rwait);
2931                 ppp_unlock(ppp);
2932                 if (atomic_dec_and_test(&ppp->file.refcnt))
2933                         ppp_destroy_interface(ppp);
2934                 err = 0;
2935         }
2936         return err;
2937 }
2938
2939 /*
2940  * Free up the resources used by a ppp channel.
2941  */
2942 static void ppp_destroy_channel(struct channel *pch)
2943 {
2944         atomic_dec(&channel_count);
2945
2946         if (!pch->file.dead) {
2947                 /* "can't happen" */
2948                 pr_err("ppp: destroying undead channel %p !\n", pch);
2949                 return;
2950         }
2951         skb_queue_purge(&pch->file.xq);
2952         skb_queue_purge(&pch->file.rq);
2953         kfree(pch);
2954 }
2955
2956 static void __exit ppp_cleanup(void)
2957 {
2958         /* should never happen */
2959         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2960                 pr_err("PPP: removing module but units remain!\n");
2961         unregister_chrdev(PPP_MAJOR, "ppp");
2962         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2963         class_destroy(ppp_class);
2964         unregister_pernet_device(&ppp_net_ops);
2965 }
2966
2967 /*
2968  * Units handling. Caller must protect concurrent access
2969  * by holding all_ppp_mutex
2970  */
2971
2972 /* associate pointer with specified number */
2973 static int unit_set(struct idr *p, void *ptr, int n)
2974 {
2975         int unit;
2976
2977         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
2978         if (unit == -ENOSPC)
2979                 unit = -EINVAL;
2980         return unit;
2981 }
2982
2983 /* get new free unit number and associate pointer with it */
2984 static int unit_get(struct idr *p, void *ptr)
2985 {
2986         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
2987 }
2988
2989 /* put unit number back to a pool */
2990 static void unit_put(struct idr *p, int n)
2991 {
2992         idr_remove(p, n);
2993 }
2994
2995 /* get pointer associated with the number */
2996 static void *unit_find(struct idr *p, int n)
2997 {
2998         return idr_find(p, n);
2999 }
3000
3001 /* Module/initialization stuff */
3002
3003 module_init(ppp_init);
3004 module_exit(ppp_cleanup);
3005
3006 EXPORT_SYMBOL(ppp_register_net_channel);
3007 EXPORT_SYMBOL(ppp_register_channel);
3008 EXPORT_SYMBOL(ppp_unregister_channel);
3009 EXPORT_SYMBOL(ppp_channel_index);
3010 EXPORT_SYMBOL(ppp_unit_number);
3011 EXPORT_SYMBOL(ppp_dev_name);
3012 EXPORT_SYMBOL(ppp_input);
3013 EXPORT_SYMBOL(ppp_input_error);
3014 EXPORT_SYMBOL(ppp_output_wakeup);
3015 EXPORT_SYMBOL(ppp_register_compressor);
3016 EXPORT_SYMBOL(ppp_unregister_compressor);
3017 MODULE_LICENSE("GPL");
3018 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3019 MODULE_ALIAS("devname:ppp");