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 bpf_prog *pass_filter;   /* filter for packets to pass */
 147         struct bpf_prog *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,
 273                                         struct file *file, int *retp);
 274 static void init_ppp_file(struct ppp_file *pf, int kind);
 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 const struct net_device_ops ppp_netdev_ops;
 287
 288 static struct class *ppp_class;
 289
 290 /* per net-namespace data */
 291 static inline struct ppp_net *ppp_pernet(struct net *net)
 292 {
 293         BUG_ON(!net);
 294
 295         return net_generic(net, ppp_net_id);
 296 }
 297
 298 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 299 static inline int proto_to_npindex(int proto)
 300 {
 301         switch (proto) {
 302         case PPP_IP:
 303                 return NP_IP;
 304         case PPP_IPV6:
 305                 return NP_IPV6;
 306         case PPP_IPX:
 307                 return NP_IPX;
 308         case PPP_AT:
 309                 return NP_AT;
 310         case PPP_MPLS_UC:
 311                 return NP_MPLS_UC;
 312         case PPP_MPLS_MC:
 313                 return NP_MPLS_MC;
 314         }
 315         return -EINVAL;
 316 }
 317
 318 /* Translates an NP index into a PPP protocol number */
 319 static const int npindex_to_proto[NUM_NP] = {
 320         PPP_IP,
 321         PPP_IPV6,
 322         PPP_IPX,
 323         PPP_AT,
 324         PPP_MPLS_UC,
 325         PPP_MPLS_MC,
 326 };
 327
 328 /* Translates an ethertype into an NP index */
 329 static inline int ethertype_to_npindex(int ethertype)
 330 {
 331         switch (ethertype) {
 332         case ETH_P_IP:
 333                 return NP_IP;
 334         case ETH_P_IPV6:
 335                 return NP_IPV6;
 336         case ETH_P_IPX:
 337                 return NP_IPX;
 338         case ETH_P_PPPTALK:
 339         case ETH_P_ATALK:
 340                 return NP_AT;
 341         case ETH_P_MPLS_UC:
 342                 return NP_MPLS_UC;
 343         case ETH_P_MPLS_MC:
 344                 return NP_MPLS_MC;
 345         }
 346         return -1;
 347 }
 348
 349 /* Translates an NP index into an ethertype */
 350 static const int npindex_to_ethertype[NUM_NP] = {
 351         ETH_P_IP,
 352         ETH_P_IPV6,
 353         ETH_P_IPX,
 354         ETH_P_PPPTALK,
 355         ETH_P_MPLS_UC,
 356         ETH_P_MPLS_MC,
 357 };
 358
 359 /*
 360  * Locking shorthand.
 361  */
 362 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 363 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 364 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 365 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 366 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 367                                      ppp_recv_lock(ppp); } while (0)
 368 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 369                                      ppp_xmit_unlock(ppp); } while (0)
 370
 371 /*
 372  * /dev/ppp device routines.
 373  * The /dev/ppp device is used by pppd to control the ppp unit.
 374  * It supports the read, write, ioctl and poll functions.
 375  * Open instances of /dev/ppp can be in one of three states:
 376  * unattached, attached to a ppp unit, or attached to a ppp channel.
 377  */
 378 static int ppp_open(struct inode *inode, struct file *file)
 379 {
 380         /*
 381          * This could (should?) be enforced by the permissions on /dev/ppp.
 382          */
 383         if (!capable(CAP_NET_ADMIN))
 384                 return -EPERM;
 385         return 0;
 386 }
 387
 388 static int ppp_release(struct inode *unused, struct file *file)
 389 {
 390         struct ppp_file *pf = file->private_data;
 391         struct ppp *ppp;
 392
 393         if (pf) {
 394                 file->private_data = NULL;
 395                 if (pf->kind == INTERFACE) {
 396                         ppp = PF_TO_PPP(pf);
 397                         rtnl_lock();
 398                         if (file == ppp->owner)
 399                                 unregister_netdevice(ppp->dev);
 400                         rtnl_unlock();
 401                 }
 402                 if (atomic_dec_and_test(&pf->refcnt)) {
 403                         switch (pf->kind) {
 404                         case INTERFACE:
 405                                 ppp_destroy_interface(PF_TO_PPP(pf));
 406                                 break;
 407                         case CHANNEL:
 408                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 409                                 break;
 410                         }
 411                 }
 412         }
 413         return 0;
 414 }
 415
 416 static ssize_t ppp_read(struct file *file, char __user *buf,
 417                         size_t count, loff_t *ppos)
 418 {
 419         struct ppp_file *pf = file->private_data;
 420         DECLARE_WAITQUEUE(wait, current);
 421         ssize_t ret;
 422         struct sk_buff *skb = NULL;
 423         struct iovec iov;
 424         struct iov_iter to;
 425
 426         ret = count;
 427
 428         if (!pf)
 429                 return -ENXIO;
 430         add_wait_queue(&pf->rwait, &wait);
 431         for (;;) {
 432                 set_current_state(TASK_INTERRUPTIBLE);
 433                 skb = skb_dequeue(&pf->rq);
 434                 if (skb)
 435                         break;
 436                 ret = 0;
 437                 if (pf->dead)
 438                         break;
 439                 if (pf->kind == INTERFACE) {
 440                         /*
 441                          * Return 0 (EOF) on an interface that has no
 442                          * channels connected, unless it is looping
 443                          * network traffic (demand mode).
 444                          */
 445                         struct ppp *ppp = PF_TO_PPP(pf);
 446                         if (ppp->n_channels == 0 &&
 447                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 448                                 break;
 449                 }
 450                 ret = -EAGAIN;
 451                 if (file->f_flags & O_NONBLOCK)
 452                         break;
 453                 ret = -ERESTARTSYS;
 454                 if (signal_pending(current))
 455                         break;
 456                 schedule();
 457         }
 458         set_current_state(TASK_RUNNING);
 459         remove_wait_queue(&pf->rwait, &wait);
 460
 461         if (!skb)
 462                 goto out;
 463
 464         ret = -EOVERFLOW;
 465         if (skb->len > count)
 466                 goto outf;
 467         ret = -EFAULT;
 468         iov.iov_base = buf;
 469         iov.iov_len = count;
 470         iov_iter_init(&to, READ, &iov, 1, count);
 471         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 472                 goto outf;
 473         ret = skb->len;
 474
 475  outf:
 476         kfree_skb(skb);
 477  out:
 478         return ret;
 479 }
 480
 481 static ssize_t ppp_write(struct file *file, const char __user *buf,
 482                          size_t count, loff_t *ppos)
 483 {
 484         struct ppp_file *pf = file->private_data;
 485         struct sk_buff *skb;
 486         ssize_t ret;
 487
 488         if (!pf)
 489                 return -ENXIO;
 490         ret = -ENOMEM;
 491         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 492         if (!skb)
 493                 goto out;
 494         skb_reserve(skb, pf->hdrlen);
 495         ret = -EFAULT;
 496         if (copy_from_user(skb_put(skb, count), buf, count)) {
 497                 kfree_skb(skb);
 498                 goto out;
 499         }
 500
 501         skb_queue_tail(&pf->xq, skb);
 502
 503         switch (pf->kind) {
 504         case INTERFACE:
 505                 ppp_xmit_process(PF_TO_PPP(pf));
 506                 break;
 507         case CHANNEL:
 508                 ppp_channel_push(PF_TO_CHANNEL(pf));
 509                 break;
 510         }
 511
 512         ret = count;
 513
 514  out:
 515         return ret;
 516 }
 517
 518 /* No kernel lock - fine */
 519 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 520 {
 521         struct ppp_file *pf = file->private_data;
 522         unsigned int mask;
 523
 524         if (!pf)
 525                 return 0;
 526         poll_wait(file, &pf->rwait, wait);
 527         mask = POLLOUT | POLLWRNORM;
 528         if (skb_peek(&pf->rq))
 529                 mask |= POLLIN | POLLRDNORM;
 530         if (pf->dead)
 531                 mask |= POLLHUP;
 532         else if (pf->kind == INTERFACE) {
 533                 /* see comment in ppp_read */
 534                 struct ppp *ppp = PF_TO_PPP(pf);
 535                 if (ppp->n_channels == 0 &&
 536                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 537                         mask |= POLLIN | POLLRDNORM;
 538         }
 539
 540         return mask;
 541 }
 542
 543 #ifdef CONFIG_PPP_FILTER
 544 static int get_filter(void __user *arg, struct sock_filter **p)
 545 {
 546         struct sock_fprog uprog;
 547         struct sock_filter *code = NULL;
 548         int len;
 549
 550         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 551                 return -EFAULT;
 552
 553         if (!uprog.len) {
 554                 *p = NULL;
 555                 return 0;
 556         }
 557
 558         len = uprog.len * sizeof(struct sock_filter);
 559         code = memdup_user(uprog.filter, len);
 560         if (IS_ERR(code))
 561                 return PTR_ERR(code);
 562
 563         *p = code;
 564         return uprog.len;
 565 }
 566 #endif /* CONFIG_PPP_FILTER */
 567
 568 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 569 {
 570         struct ppp_file *pf = file->private_data;
 571         struct ppp *ppp;
 572         int err = -EFAULT, val, val2, i;
 573         struct ppp_idle idle;
 574         struct npioctl npi;
 575         int unit, cflags;
 576         struct slcompress *vj;
 577         void __user *argp = (void __user *)arg;
 578         int __user *p = argp;
 579
 580         if (!pf)
 581                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
 582                                         pf, file, cmd, arg);
 583
 584         if (cmd == PPPIOCDETACH) {
 585                 /*
 586                  * We have to be careful here... if the file descriptor
 587                  * has been dup'd, we could have another process in the
 588                  * middle of a poll using the same file *, so we had
 589                  * better not free the interface data structures -
 590                  * instead we fail the ioctl.  Even in this case, we
 591                  * shut down the interface if we are the owner of it.
 592                  * Actually, we should get rid of PPPIOCDETACH, userland
 593                  * (i.e. pppd) could achieve the same effect by closing
 594                  * this fd and reopening /dev/ppp.
 595                  */
 596                 err = -EINVAL;
 597                 mutex_lock(&ppp_mutex);
 598                 if (pf->kind == INTERFACE) {
 599                         ppp = PF_TO_PPP(pf);
 600                         rtnl_lock();
 601                         if (file == ppp->owner)
 602                                 unregister_netdevice(ppp->dev);
 603                         rtnl_unlock();
 604                 }
 605                 if (atomic_long_read(&file->f_count) < 2) {
 606                         ppp_release(NULL, file);
 607                         err = 0;
 608                 } else
 609                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 610                                 atomic_long_read(&file->f_count));
 611                 mutex_unlock(&ppp_mutex);
 612                 return err;
 613         }
 614
 615         if (pf->kind == CHANNEL) {
 616                 struct channel *pch;
 617                 struct ppp_channel *chan;
 618
 619                 mutex_lock(&ppp_mutex);
 620                 pch = PF_TO_CHANNEL(pf);
 621
 622                 switch (cmd) {
 623                 case PPPIOCCONNECT:
 624                         if (get_user(unit, p))
 625                                 break;
 626                         err = ppp_connect_channel(pch, unit);
 627                         break;
 628
 629                 case PPPIOCDISCONN:
 630                         err = ppp_disconnect_channel(pch);
 631                         break;
 632
 633                 default:
 634                         down_read(&pch->chan_sem);
 635                         chan = pch->chan;
 636                         err = -ENOTTY;
 637                         if (chan && chan->ops->ioctl)
 638                                 err = chan->ops->ioctl(chan, cmd, arg);
 639                         up_read(&pch->chan_sem);
 640                 }
 641                 mutex_unlock(&ppp_mutex);
 642                 return err;
 643         }
 644
 645         if (pf->kind != INTERFACE) {
 646                 /* can't happen */
 647                 pr_err("PPP: not interface or channel??\n");
 648                 return -EINVAL;
 649         }
 650
 651         mutex_lock(&ppp_mutex);
 652         ppp = PF_TO_PPP(pf);
 653         switch (cmd) {
 654         case PPPIOCSMRU:
 655                 if (get_user(val, p))
 656                         break;
 657                 ppp->mru = val;
 658                 err = 0;
 659                 break;
 660
 661         case PPPIOCSFLAGS:
 662                 if (get_user(val, p))
 663                         break;
 664                 ppp_lock(ppp);
 665                 cflags = ppp->flags & ~val;
 666 #ifdef CONFIG_PPP_MULTILINK
 667                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 668                         ppp->nextseq = 0;
 669 #endif
 670                 ppp->flags = val & SC_FLAG_BITS;
 671                 ppp_unlock(ppp);
 672                 if (cflags & SC_CCP_OPEN)
 673                         ppp_ccp_closed(ppp);
 674                 err = 0;
 675                 break;
 676
 677         case PPPIOCGFLAGS:
 678                 val = ppp->flags | ppp->xstate | ppp->rstate;
 679                 if (put_user(val, p))
 680                         break;
 681                 err = 0;
 682                 break;
 683
 684         case PPPIOCSCOMPRESS:
 685                 err = ppp_set_compress(ppp, arg);
 686                 break;
 687
 688         case PPPIOCGUNIT:
 689                 if (put_user(ppp->file.index, p))
 690                         break;
 691                 err = 0;
 692                 break;
 693
 694         case PPPIOCSDEBUG:
 695                 if (get_user(val, p))
 696                         break;
 697                 ppp->debug = val;
 698                 err = 0;
 699                 break;
 700
 701         case PPPIOCGDEBUG:
 702                 if (put_user(ppp->debug, p))
 703                         break;
 704                 err = 0;
 705                 break;
 706
 707         case PPPIOCGIDLE:
 708                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 709                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 710                 if (copy_to_user(argp, &idle, sizeof(idle)))
 711                         break;
 712                 err = 0;
 713                 break;
 714
 715         case PPPIOCSMAXCID:
 716                 if (get_user(val, p))
 717                         break;
 718                 val2 = 15;
 719                 if ((val >> 16) != 0) {
 720                         val2 = val >> 16;
 721                         val &= 0xffff;
 722                 }
 723                 vj = slhc_init(val2+1, val+1);
 724                 if (!vj) {
 725                         netdev_err(ppp->dev,
 726                                    "PPP: no memory (VJ compressor)\n");
 727                         err = -ENOMEM;
 728                         break;
 729                 }
 730                 ppp_lock(ppp);
 731                 if (ppp->vj)
 732                         slhc_free(ppp->vj);
 733                 ppp->vj = vj;
 734                 ppp_unlock(ppp);
 735                 err = 0;
 736                 break;
 737
 738         case PPPIOCGNPMODE:
 739         case PPPIOCSNPMODE:
 740                 if (copy_from_user(&npi, argp, sizeof(npi)))
 741                         break;
 742                 err = proto_to_npindex(npi.protocol);
 743                 if (err < 0)
 744                         break;
 745                 i = err;
 746                 if (cmd == PPPIOCGNPMODE) {
 747                         err = -EFAULT;
 748                         npi.mode = ppp->npmode[i];
 749                         if (copy_to_user(argp, &npi, sizeof(npi)))
 750                                 break;
 751                 } else {
 752                         ppp->npmode[i] = npi.mode;
 753                         /* we may be able to transmit more packets now (??) */
 754                         netif_wake_queue(ppp->dev);
 755                 }
 756                 err = 0;
 757                 break;
 758
 759 #ifdef CONFIG_PPP_FILTER
 760         case PPPIOCSPASS:
 761         {
 762                 struct sock_filter *code;
 763
 764                 err = get_filter(argp, &code);
 765                 if (err >= 0) {
 766                         struct bpf_prog *pass_filter = NULL;
 767                         struct sock_fprog_kern fprog = {
 768                                 .len = err,
 769                                 .filter = code,
 770                         };
 771
 772                         err = 0;
 773                         if (fprog.filter)
 774                                 err = bpf_prog_create(&pass_filter, &fprog);
 775                         if (!err) {
 776                                 ppp_lock(ppp);
 777                                 if (ppp->pass_filter)
 778                                         bpf_prog_destroy(ppp->pass_filter);
 779                                 ppp->pass_filter = pass_filter;
 780                                 ppp_unlock(ppp);
 781                         }
 782                         kfree(code);
 783                 }
 784                 break;
 785         }
 786         case PPPIOCSACTIVE:
 787         {
 788                 struct sock_filter *code;
 789
 790                 err = get_filter(argp, &code);
 791                 if (err >= 0) {
 792                         struct bpf_prog *active_filter = NULL;
 793                         struct sock_fprog_kern fprog = {
 794                                 .len = err,
 795                                 .filter = code,
 796                         };
 797
 798                         err = 0;
 799                         if (fprog.filter)
 800                                 err = bpf_prog_create(&active_filter, &fprog);
 801                         if (!err) {
 802                                 ppp_lock(ppp);
 803                                 if (ppp->active_filter)
 804                                         bpf_prog_destroy(ppp->active_filter);
 805                                 ppp->active_filter = active_filter;
 806                                 ppp_unlock(ppp);
 807                         }
 808                         kfree(code);
 809                 }
 810                 break;
 811         }
 812 #endif /* CONFIG_PPP_FILTER */
 813
 814 #ifdef CONFIG_PPP_MULTILINK
 815         case PPPIOCSMRRU:
 816                 if (get_user(val, p))
 817                         break;
 818                 ppp_recv_lock(ppp);
 819                 ppp->mrru = val;
 820                 ppp_recv_unlock(ppp);
 821                 err = 0;
 822                 break;
 823 #endif /* CONFIG_PPP_MULTILINK */
 824
 825         default:
 826                 err = -ENOTTY;
 827         }
 828         mutex_unlock(&ppp_mutex);
 829         return err;
 830 }
 831
 832 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 833                         struct file *file, unsigned int cmd, unsigned long arg)
 834 {
 835         int unit, err = -EFAULT;
 836         struct ppp *ppp;
 837         struct channel *chan;
 838         struct ppp_net *pn;
 839         int __user *p = (int __user *)arg;
 840
 841         mutex_lock(&ppp_mutex);
 842         switch (cmd) {
 843         case PPPIOCNEWUNIT:
 844                 /* Create a new ppp unit */
 845                 if (get_user(unit, p))
 846                         break;
 847                 ppp = ppp_create_interface(net, unit, file, &err);
 848                 if (!ppp)
 849                         break;
 850                 file->private_data = &ppp->file;
 851                 err = -EFAULT;
 852                 if (put_user(ppp->file.index, p))
 853                         break;
 854                 err = 0;
 855                 break;
 856
 857         case PPPIOCATTACH:
 858                 /* Attach to an existing ppp unit */
 859                 if (get_user(unit, p))
 860                         break;
 861                 err = -ENXIO;
 862                 pn = ppp_pernet(net);
 863                 mutex_lock(&pn->all_ppp_mutex);
 864                 ppp = ppp_find_unit(pn, unit);
 865                 if (ppp) {
 866                         atomic_inc(&ppp->file.refcnt);
 867                         file->private_data = &ppp->file;
 868                         err = 0;
 869                 }
 870                 mutex_unlock(&pn->all_ppp_mutex);
 871                 break;
 872
 873         case PPPIOCATTCHAN:
 874                 if (get_user(unit, p))
 875                         break;
 876                 err = -ENXIO;
 877                 pn = ppp_pernet(net);
 878                 spin_lock_bh(&pn->all_channels_lock);
 879                 chan = ppp_find_channel(pn, unit);
 880                 if (chan) {
 881                         atomic_inc(&chan->file.refcnt);
 882                         file->private_data = &chan->file;
 883                         err = 0;
 884                 }
 885                 spin_unlock_bh(&pn->all_channels_lock);
 886                 break;
 887
 888         default:
 889                 err = -ENOTTY;
 890         }
 891         mutex_unlock(&ppp_mutex);
 892         return err;
 893 }
 894
 895 static const struct file_operations ppp_device_fops = {
 896         .owner          = THIS_MODULE,
 897         .read           = ppp_read,
 898         .write          = ppp_write,
 899         .poll           = ppp_poll,
 900         .unlocked_ioctl = ppp_ioctl,
 901         .open           = ppp_open,
 902         .release        = ppp_release,
 903         .llseek         = noop_llseek,
 904 };
 905
 906 static __net_init int ppp_init_net(struct net *net)
 907 {
 908         struct ppp_net *pn = net_generic(net, ppp_net_id);
 909
 910         idr_init(&pn->units_idr);
 911         mutex_init(&pn->all_ppp_mutex);
 912
 913         INIT_LIST_HEAD(&pn->all_channels);
 914         INIT_LIST_HEAD(&pn->new_channels);
 915
 916         spin_lock_init(&pn->all_channels_lock);
 917
 918         return 0;
 919 }
 920
 921 static __net_exit void ppp_exit_net(struct net *net)
 922 {
 923         struct ppp_net *pn = net_generic(net, ppp_net_id);
 924         struct net_device *dev;
 925         struct net_device *aux;
 926         struct ppp *ppp;
 927         LIST_HEAD(list);
 928         int id;
 929
 930         rtnl_lock();
 931         for_each_netdev_safe(net, dev, aux) {
 932                 if (dev->netdev_ops == &ppp_netdev_ops)
 933                         unregister_netdevice_queue(dev, &list);
 934         }
 935
 936         idr_for_each_entry(&pn->units_idr, ppp, id)
 937                 /* Skip devices already unregistered by previous loop */
 938                 if (!net_eq(dev_net(ppp->dev), net))
 939                         unregister_netdevice_queue(ppp->dev, &list);
 940
 941         unregister_netdevice_many(&list);
 942         rtnl_unlock();
 943
 944         idr_destroy(&pn->units_idr);
 945 }
 946
 947 static struct pernet_operations ppp_net_ops = {
 948         .init = ppp_init_net,
 949         .exit = ppp_exit_net,
 950         .id   = &ppp_net_id,
 951         .size = sizeof(struct ppp_net),
 952 };
 953
 954 #define PPP_MAJOR       108
 955
 956 /* Called at boot time if ppp is compiled into the kernel,
 957    or at module load time (from init_module) if compiled as a module. */
 958 static int __init ppp_init(void)
 959 {
 960         int err;
 961
 962         pr_info("PPP generic driver version " PPP_VERSION "\n");
 963
 964         err = register_pernet_device(&ppp_net_ops);
 965         if (err) {
 966                 pr_err("failed to register PPP pernet device (%d)\n", err);
 967                 goto out;
 968         }
 969
 970         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 971         if (err) {
 972                 pr_err("failed to register PPP device (%d)\n", err);
 973                 goto out_net;
 974         }
 975
 976         ppp_class = class_create(THIS_MODULE, "ppp");
 977         if (IS_ERR(ppp_class)) {
 978                 err = PTR_ERR(ppp_class);
 979                 goto out_chrdev;
 980         }
 981
 982         /* not a big deal if we fail here :-) */
 983         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 984
 985         return 0;
 986
 987 out_chrdev:
 988         unregister_chrdev(PPP_MAJOR, "ppp");
 989 out_net:
 990         unregister_pernet_device(&ppp_net_ops);
 991 out:
 992         return err;
 993 }
 994
 995 /*
 996  * Network interface unit routines.
 997  */
 998 static netdev_tx_t
 999 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1000 {
1001         struct ppp *ppp = netdev_priv(dev);
1002         int npi, proto;
1003         unsigned char *pp;
1004
1005         npi = ethertype_to_npindex(ntohs(skb->protocol));
1006         if (npi < 0)
1007                 goto outf;
1008
1009         /* Drop, accept or reject the packet */
1010         switch (ppp->npmode[npi]) {
1011         case NPMODE_PASS:
1012                 break;
1013         case NPMODE_QUEUE:
1014                 /* it would be nice to have a way to tell the network
1015                    system to queue this one up for later. */
1016                 goto outf;
1017         case NPMODE_DROP:
1018         case NPMODE_ERROR:
1019                 goto outf;
1020         }
1021
1022         /* Put the 2-byte PPP protocol number on the front,
1023            making sure there is room for the address and control fields. */
1024         if (skb_cow_head(skb, PPP_HDRLEN))
1025                 goto outf;
1026
1027         pp = skb_push(skb, 2);
1028         proto = npindex_to_proto[npi];
1029         put_unaligned_be16(proto, pp);
1030
1031         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1032         skb_queue_tail(&ppp->file.xq, skb);
1033         ppp_xmit_process(ppp);
1034         return NETDEV_TX_OK;
1035
1036  outf:
1037         kfree_skb(skb);
1038         ++dev->stats.tx_dropped;
1039         return NETDEV_TX_OK;
1040 }
1041
1042 static int
1043 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1044 {
1045         struct ppp *ppp = netdev_priv(dev);
1046         int err = -EFAULT;
1047         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1048         struct ppp_stats stats;
1049         struct ppp_comp_stats cstats;
1050         char *vers;
1051
1052         switch (cmd) {
1053         case SIOCGPPPSTATS:
1054                 ppp_get_stats(ppp, &stats);
1055                 if (copy_to_user(addr, &stats, sizeof(stats)))
1056                         break;
1057                 err = 0;
1058                 break;
1059
1060         case SIOCGPPPCSTATS:
1061                 memset(&cstats, 0, sizeof(cstats));
1062                 if (ppp->xc_state)
1063                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1064                 if (ppp->rc_state)
1065                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1066                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1067                         break;
1068                 err = 0;
1069                 break;
1070
1071         case SIOCGPPPVER:
1072                 vers = PPP_VERSION;
1073                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1074                         break;
1075                 err = 0;
1076                 break;
1077
1078         default:
1079                 err = -EINVAL;
1080         }
1081
1082         return err;
1083 }
1084
1085 static struct rtnl_link_stats64*
1086 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1087 {
1088         struct ppp *ppp = netdev_priv(dev);
1089
1090         ppp_recv_lock(ppp);
1091         stats64->rx_packets = ppp->stats64.rx_packets;
1092         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1093         ppp_recv_unlock(ppp);
1094
1095         ppp_xmit_lock(ppp);
1096         stats64->tx_packets = ppp->stats64.tx_packets;
1097         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1098         ppp_xmit_unlock(ppp);
1099
1100         stats64->rx_errors        = dev->stats.rx_errors;
1101         stats64->tx_errors        = dev->stats.tx_errors;
1102         stats64->rx_dropped       = dev->stats.rx_dropped;
1103         stats64->tx_dropped       = dev->stats.tx_dropped;
1104         stats64->rx_length_errors = dev->stats.rx_length_errors;
1105
1106         return stats64;
1107 }
1108
1109 static struct lock_class_key ppp_tx_busylock;
1110 static int ppp_dev_init(struct net_device *dev)
1111 {
1112         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1113         return 0;
1114 }
1115
1116 static void ppp_dev_uninit(struct net_device *dev)
1117 {
1118         struct ppp *ppp = netdev_priv(dev);
1119         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1120
1121         ppp_lock(ppp);
1122         ppp->closing = 1;
1123         ppp_unlock(ppp);
1124
1125         mutex_lock(&pn->all_ppp_mutex);
1126         unit_put(&pn->units_idr, ppp->file.index);
1127         mutex_unlock(&pn->all_ppp_mutex);
1128
1129         ppp->owner = NULL;
1130
1131         ppp->file.dead = 1;
1132         wake_up_interruptible(&ppp->file.rwait);
1133 }
1134
1135 static const struct net_device_ops ppp_netdev_ops = {
1136         .ndo_init        = ppp_dev_init,
1137         .ndo_uninit      = ppp_dev_uninit,
1138         .ndo_start_xmit  = ppp_start_xmit,
1139         .ndo_do_ioctl    = ppp_net_ioctl,
1140         .ndo_get_stats64 = ppp_get_stats64,
1141 };
1142
1143 static void ppp_setup(struct net_device *dev)
1144 {
1145         dev->netdev_ops = &ppp_netdev_ops;
1146         dev->hard_header_len = PPP_HDRLEN;
1147         dev->mtu = PPP_MRU;
1148         dev->addr_len = 0;
1149         dev->tx_queue_len = 3;
1150         dev->type = ARPHRD_PPP;
1151         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1152         netif_keep_dst(dev);
1153 }
1154
1155 /*
1156  * Transmit-side routines.
1157  */
1158
1159 /*
1160  * Called to do any work queued up on the transmit side
1161  * that can now be done.
1162  */
1163 static void
1164 ppp_xmit_process(struct ppp *ppp)
1165 {
1166         struct sk_buff *skb;
1167
1168         ppp_xmit_lock(ppp);
1169         if (!ppp->closing) {
1170                 ppp_push(ppp);
1171                 while (!ppp->xmit_pending &&
1172                        (skb = skb_dequeue(&ppp->file.xq)))
1173                         ppp_send_frame(ppp, skb);
1174                 /* If there's no work left to do, tell the core net
1175                    code that we can accept some more. */
1176                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1177                         netif_wake_queue(ppp->dev);
1178                 else
1179                         netif_stop_queue(ppp->dev);
1180         }
1181         ppp_xmit_unlock(ppp);
1182 }
1183
1184 static inline struct sk_buff *
1185 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1186 {
1187         struct sk_buff *new_skb;
1188         int len;
1189         int new_skb_size = ppp->dev->mtu +
1190                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1191         int compressor_skb_size = ppp->dev->mtu +
1192                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1193         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1194         if (!new_skb) {
1195                 if (net_ratelimit())
1196                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1197                 return NULL;
1198         }
1199         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1200                 skb_reserve(new_skb,
1201                             ppp->dev->hard_header_len - PPP_HDRLEN);
1202
1203         /* compressor still expects A/C bytes in hdr */
1204         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1205                                    new_skb->data, skb->len + 2,
1206                                    compressor_skb_size);
1207         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1208                 consume_skb(skb);
1209                 skb = new_skb;
1210                 skb_put(skb, len);
1211                 skb_pull(skb, 2);       /* pull off A/C bytes */
1212         } else if (len == 0) {
1213                 /* didn't compress, or CCP not up yet */
1214                 consume_skb(new_skb);
1215                 new_skb = skb;
1216         } else {
1217                 /*
1218                  * (len < 0)
1219                  * MPPE requires that we do not send unencrypted
1220                  * frames.  The compressor will return -1 if we
1221                  * should drop the frame.  We cannot simply test
1222                  * the compress_proto because MPPE and MPPC share
1223                  * the same number.
1224                  */
1225                 if (net_ratelimit())
1226                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1227                 kfree_skb(skb);
1228                 consume_skb(new_skb);
1229                 new_skb = NULL;
1230         }
1231         return new_skb;
1232 }
1233
1234 /*
1235  * Compress and send a frame.
1236  * The caller should have locked the xmit path,
1237  * and xmit_pending should be 0.
1238  */
1239 static void
1240 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1241 {
1242         int proto = PPP_PROTO(skb);
1243         struct sk_buff *new_skb;
1244         int len;
1245         unsigned char *cp;
1246
1247         if (proto < 0x8000) {
1248 #ifdef CONFIG_PPP_FILTER
1249                 /* check if we should pass this packet */
1250                 /* the filter instructions are constructed assuming
1251                    a four-byte PPP header on each packet */
1252                 *skb_push(skb, 2) = 1;
1253                 if (ppp->pass_filter &&
1254                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1255                         if (ppp->debug & 1)
1256                                 netdev_printk(KERN_DEBUG, ppp->dev,
1257                                               "PPP: outbound frame "
1258                                               "not passed\n");
1259                         kfree_skb(skb);
1260                         return;
1261                 }
1262                 /* if this packet passes the active filter, record the time */
1263                 if (!(ppp->active_filter &&
1264                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1265                         ppp->last_xmit = jiffies;
1266                 skb_pull(skb, 2);
1267 #else
1268                 /* for data packets, record the time */
1269                 ppp->last_xmit = jiffies;
1270 #endif /* CONFIG_PPP_FILTER */
1271         }
1272
1273         ++ppp->stats64.tx_packets;
1274         ppp->stats64.tx_bytes += skb->len - 2;
1275
1276         switch (proto) {
1277         case PPP_IP:
1278                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1279                         break;
1280                 /* try to do VJ TCP header compression */
1281                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1282                                     GFP_ATOMIC);
1283                 if (!new_skb) {
1284                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1285                         goto drop;
1286                 }
1287                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1288                 cp = skb->data + 2;
1289                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1290                                     new_skb->data + 2, &cp,
1291                                     !(ppp->flags & SC_NO_TCP_CCID));
1292                 if (cp == skb->data + 2) {
1293                         /* didn't compress */
1294                         consume_skb(new_skb);
1295                 } else {
1296                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1297                                 proto = PPP_VJC_COMP;
1298                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1299                         } else {
1300                                 proto = PPP_VJC_UNCOMP;
1301                                 cp[0] = skb->data[2];
1302                         }
1303                         consume_skb(skb);
1304                         skb = new_skb;
1305                         cp = skb_put(skb, len + 2);
1306                         cp[0] = 0;
1307                         cp[1] = proto;
1308                 }
1309                 break;
1310
1311         case PPP_CCP:
1312                 /* peek at outbound CCP frames */
1313                 ppp_ccp_peek(ppp, skb, 0);
1314                 break;
1315         }
1316
1317         /* try to do packet compression */
1318         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1319             proto != PPP_LCP && proto != PPP_CCP) {
1320                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1321                         if (net_ratelimit())
1322                                 netdev_err(ppp->dev,
1323                                            "ppp: compression required but "
1324                                            "down - pkt dropped.\n");
1325                         goto drop;
1326                 }
1327                 skb = pad_compress_skb(ppp, skb);
1328                 if (!skb)
1329                         goto drop;
1330         }
1331
1332         /*
1333          * If we are waiting for traffic (demand dialling),
1334          * queue it up for pppd to receive.
1335          */
1336         if (ppp->flags & SC_LOOP_TRAFFIC) {
1337                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1338                         goto drop;
1339                 skb_queue_tail(&ppp->file.rq, skb);
1340                 wake_up_interruptible(&ppp->file.rwait);
1341                 return;
1342         }
1343
1344         ppp->xmit_pending = skb;
1345         ppp_push(ppp);
1346         return;
1347
1348  drop:
1349         kfree_skb(skb);
1350         ++ppp->dev->stats.tx_errors;
1351 }
1352
1353 /*
1354  * Try to send the frame in xmit_pending.
1355  * The caller should have the xmit path locked.
1356  */
1357 static void
1358 ppp_push(struct ppp *ppp)
1359 {
1360         struct list_head *list;
1361         struct channel *pch;
1362         struct sk_buff *skb = ppp->xmit_pending;
1363
1364         if (!skb)
1365                 return;
1366
1367         list = &ppp->channels;
1368         if (list_empty(list)) {
1369                 /* nowhere to send the packet, just drop it */
1370                 ppp->xmit_pending = NULL;
1371                 kfree_skb(skb);
1372                 return;
1373         }
1374
1375         if ((ppp->flags & SC_MULTILINK) == 0) {
1376                 /* not doing multilink: send it down the first channel */
1377                 list = list->next;
1378                 pch = list_entry(list, struct channel, clist);
1379
1380                 spin_lock_bh(&pch->downl);
1381                 if (pch->chan) {
1382                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1383                                 ppp->xmit_pending = NULL;
1384                 } else {
1385                         /* channel got unregistered */
1386                         kfree_skb(skb);
1387                         ppp->xmit_pending = NULL;
1388                 }
1389                 spin_unlock_bh(&pch->downl);
1390                 return;
1391         }
1392
1393 #ifdef CONFIG_PPP_MULTILINK
1394         /* Multilink: fragment the packet over as many links
1395            as can take the packet at the moment. */
1396         if (!ppp_mp_explode(ppp, skb))
1397                 return;
1398 #endif /* CONFIG_PPP_MULTILINK */
1399
1400         ppp->xmit_pending = NULL;
1401         kfree_skb(skb);
1402 }
1403
1404 #ifdef CONFIG_PPP_MULTILINK
1405 static bool mp_protocol_compress __read_mostly = true;
1406 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1407 MODULE_PARM_DESC(mp_protocol_compress,
1408                  "compress protocol id in multilink fragments");
1409
1410 /*
1411  * Divide a packet to be transmitted into fragments and
1412  * send them out the individual links.
1413  */
1414 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1415 {
1416         int len, totlen;
1417         int i, bits, hdrlen, mtu;
1418         int flen;
1419         int navail, nfree, nzero;
1420         int nbigger;
1421         int totspeed;
1422         int totfree;
1423         unsigned char *p, *q;
1424         struct list_head *list;
1425         struct channel *pch;
1426         struct sk_buff *frag;
1427         struct ppp_channel *chan;
1428
1429         totspeed = 0; /*total bitrate of the bundle*/
1430         nfree = 0; /* # channels which have no packet already queued */
1431         navail = 0; /* total # of usable channels (not deregistered) */
1432         nzero = 0; /* number of channels with zero speed associated*/
1433         totfree = 0; /*total # of channels available and
1434                                   *having no queued packets before
1435                                   *starting the fragmentation*/
1436
1437         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1438         i = 0;
1439         list_for_each_entry(pch, &ppp->channels, clist) {
1440                 if (pch->chan) {
1441                         pch->avail = 1;
1442                         navail++;
1443                         pch->speed = pch->chan->speed;
1444                 } else {
1445                         pch->avail = 0;
1446                 }
1447                 if (pch->avail) {
1448                         if (skb_queue_empty(&pch->file.xq) ||
1449                                 !pch->had_frag) {
1450                                         if (pch->speed == 0)
1451                                                 nzero++;
1452                                         else
1453                                                 totspeed += pch->speed;
1454
1455                                         pch->avail = 2;
1456                                         ++nfree;
1457                                         ++totfree;
1458                                 }
1459                         if (!pch->had_frag && i < ppp->nxchan)
1460                                 ppp->nxchan = i;
1461                 }
1462                 ++i;
1463         }
1464         /*
1465          * Don't start sending this packet unless at least half of
1466          * the channels are free.  This gives much better TCP
1467          * performance if we have a lot of channels.
1468          */
1469         if (nfree == 0 || nfree < navail / 2)
1470                 return 0; /* can't take now, leave it in xmit_pending */
1471
1472         /* Do protocol field compression */
1473         p = skb->data;
1474         len = skb->len;
1475         if (*p == 0 && mp_protocol_compress) {
1476                 ++p;
1477                 --len;
1478         }
1479
1480         totlen = len;
1481         nbigger = len % nfree;
1482
1483         /* skip to the channel after the one we last used
1484            and start at that one */
1485         list = &ppp->channels;
1486         for (i = 0; i < ppp->nxchan; ++i) {
1487                 list = list->next;
1488                 if (list == &ppp->channels) {
1489                         i = 0;
1490                         break;
1491                 }
1492         }
1493
1494         /* create a fragment for each channel */
1495         bits = B;
1496         while (len > 0) {
1497                 list = list->next;
1498                 if (list == &ppp->channels) {
1499                         i = 0;
1500                         continue;
1501                 }
1502                 pch = list_entry(list, struct channel, clist);
1503                 ++i;
1504                 if (!pch->avail)
1505                         continue;
1506
1507                 /*
1508                  * Skip this channel if it has a fragment pending already and
1509                  * we haven't given a fragment to all of the free channels.
1510                  */
1511                 if (pch->avail == 1) {
1512                         if (nfree > 0)
1513                                 continue;
1514                 } else {
1515                         pch->avail = 1;
1516                 }
1517
1518                 /* check the channel's mtu and whether it is still attached. */
1519                 spin_lock_bh(&pch->downl);
1520                 if (pch->chan == NULL) {
1521                         /* can't use this channel, it's being deregistered */
1522                         if (pch->speed == 0)
1523                                 nzero--;
1524                         else
1525                                 totspeed -= pch->speed;
1526
1527                         spin_unlock_bh(&pch->downl);
1528                         pch->avail = 0;
1529                         totlen = len;
1530                         totfree--;
1531                         nfree--;
1532                         if (--navail == 0)
1533                                 break;
1534                         continue;
1535                 }
1536
1537                 /*
1538                 *if the channel speed is not set divide
1539                 *the packet evenly among the free channels;
1540                 *otherwise divide it according to the speed
1541                 *of the channel we are going to transmit on
1542                 */
1543                 flen = len;
1544                 if (nfree > 0) {
1545                         if (pch->speed == 0) {
1546                                 flen = len/nfree;
1547                                 if (nbigger > 0) {
1548                                         flen++;
1549                                         nbigger--;
1550                                 }
1551                         } else {
1552                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1553                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1554                                 if (nbigger > 0) {
1555                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1556                                         nbigger -= ((totfree - nzero)*pch->speed)/
1557                                                         totspeed;
1558                                 }
1559                         }
1560                         nfree--;
1561                 }
1562
1563                 /*
1564                  *check if we are on the last channel or
1565                  *we exceded the length of the data to
1566                  *fragment
1567                  */
1568                 if ((nfree <= 0) || (flen > len))
1569                         flen = len;
1570                 /*
1571                  *it is not worth to tx on slow channels:
1572                  *in that case from the resulting flen according to the
1573                  *above formula will be equal or less than zero.
1574                  *Skip the channel in this case
1575                  */
1576                 if (flen <= 0) {
1577                         pch->avail = 2;
1578                         spin_unlock_bh(&pch->downl);
1579                         continue;
1580                 }
1581
1582                 /*
1583                  * hdrlen includes the 2-byte PPP protocol field, but the
1584                  * MTU counts only the payload excluding the protocol field.
1585                  * (RFC1661 Section 2)
1586                  */
1587                 mtu = pch->chan->mtu - (hdrlen - 2);
1588                 if (mtu < 4)
1589                         mtu = 4;
1590                 if (flen > mtu)
1591                         flen = mtu;
1592                 if (flen == len)
1593                         bits |= E;
1594                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1595                 if (!frag)
1596                         goto noskb;
1597                 q = skb_put(frag, flen + hdrlen);
1598
1599                 /* make the MP header */
1600                 put_unaligned_be16(PPP_MP, q);
1601                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1602                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1603                         q[3] = ppp->nxseq;
1604                 } else {
1605                         q[2] = bits;
1606                         q[3] = ppp->nxseq >> 16;
1607                         q[4] = ppp->nxseq >> 8;
1608                         q[5] = ppp->nxseq;
1609                 }
1610
1611                 memcpy(q + hdrlen, p, flen);
1612
1613                 /* try to send it down the channel */
1614                 chan = pch->chan;
1615                 if (!skb_queue_empty(&pch->file.xq) ||
1616                         !chan->ops->start_xmit(chan, frag))
1617                         skb_queue_tail(&pch->file.xq, frag);
1618                 pch->had_frag = 1;
1619                 p += flen;
1620                 len -= flen;
1621                 ++ppp->nxseq;
1622                 bits = 0;
1623                 spin_unlock_bh(&pch->downl);
1624         }
1625         ppp->nxchan = i;
1626
1627         return 1;
1628
1629  noskb:
1630         spin_unlock_bh(&pch->downl);
1631         if (ppp->debug & 1)
1632                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1633         ++ppp->dev->stats.tx_errors;
1634         ++ppp->nxseq;
1635         return 1;       /* abandon the frame */
1636 }
1637 #endif /* CONFIG_PPP_MULTILINK */
1638
1639 /*
1640  * Try to send data out on a channel.
1641  */
1642 static void
1643 ppp_channel_push(struct channel *pch)
1644 {
1645         struct sk_buff *skb;
1646         struct ppp *ppp;
1647
1648         spin_lock_bh(&pch->downl);
1649         if (pch->chan) {
1650                 while (!skb_queue_empty(&pch->file.xq)) {
1651                         skb = skb_dequeue(&pch->file.xq);
1652                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1653                                 /* put the packet back and try again later */
1654                                 skb_queue_head(&pch->file.xq, skb);
1655                                 break;
1656                         }
1657                 }
1658         } else {
1659                 /* channel got deregistered */
1660                 skb_queue_purge(&pch->file.xq);
1661         }
1662         spin_unlock_bh(&pch->downl);
1663         /* see if there is anything from the attached unit to be sent */
1664         if (skb_queue_empty(&pch->file.xq)) {
1665                 read_lock_bh(&pch->upl);
1666                 ppp = pch->ppp;
1667                 if (ppp)
1668                         ppp_xmit_process(ppp);
1669                 read_unlock_bh(&pch->upl);
1670         }
1671 }
1672
1673 /*
1674  * Receive-side routines.
1675  */
1676
1677 struct ppp_mp_skb_parm {
1678         u32             sequence;
1679         u8              BEbits;
1680 };
1681 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1682
1683 static inline void
1684 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1685 {
1686         ppp_recv_lock(ppp);
1687         if (!ppp->closing)
1688                 ppp_receive_frame(ppp, skb, pch);
1689         else
1690                 kfree_skb(skb);
1691         ppp_recv_unlock(ppp);
1692 }
1693
1694 void
1695 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1696 {
1697         struct channel *pch = chan->ppp;
1698         int proto;
1699
1700         if (!pch) {
1701                 kfree_skb(skb);
1702                 return;
1703         }
1704
1705         read_lock_bh(&pch->upl);
1706         if (!pskb_may_pull(skb, 2)) {
1707                 kfree_skb(skb);
1708                 if (pch->ppp) {
1709                         ++pch->ppp->dev->stats.rx_length_errors;
1710                         ppp_receive_error(pch->ppp);
1711                 }
1712                 goto done;
1713         }
1714
1715         proto = PPP_PROTO(skb);
1716         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1717                 /* put it on the channel queue */
1718                 skb_queue_tail(&pch->file.rq, skb);
1719                 /* drop old frames if queue too long */
1720                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1721                        (skb = skb_dequeue(&pch->file.rq)))
1722                         kfree_skb(skb);
1723                 wake_up_interruptible(&pch->file.rwait);
1724         } else {
1725                 ppp_do_recv(pch->ppp, skb, pch);
1726         }
1727
1728 done:
1729         read_unlock_bh(&pch->upl);
1730 }
1731
1732 /* Put a 0-length skb in the receive queue as an error indication */
1733 void
1734 ppp_input_error(struct ppp_channel *chan, int code)
1735 {
1736         struct channel *pch = chan->ppp;
1737         struct sk_buff *skb;
1738
1739         if (!pch)
1740                 return;
1741
1742         read_lock_bh(&pch->upl);
1743         if (pch->ppp) {
1744                 skb = alloc_skb(0, GFP_ATOMIC);
1745                 if (skb) {
1746                         skb->len = 0;           /* probably unnecessary */
1747                         skb->cb[0] = code;
1748                         ppp_do_recv(pch->ppp, skb, pch);
1749                 }
1750         }
1751         read_unlock_bh(&pch->upl);
1752 }
1753
1754 /*
1755  * We come in here to process a received frame.
1756  * The receive side of the ppp unit is locked.
1757  */
1758 static void
1759 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1760 {
1761         /* note: a 0-length skb is used as an error indication */
1762         if (skb->len > 0) {
1763                 skb_checksum_complete_unset(skb);
1764 #ifdef CONFIG_PPP_MULTILINK
1765                 /* XXX do channel-level decompression here */
1766                 if (PPP_PROTO(skb) == PPP_MP)
1767                         ppp_receive_mp_frame(ppp, skb, pch);
1768                 else
1769 #endif /* CONFIG_PPP_MULTILINK */
1770                         ppp_receive_nonmp_frame(ppp, skb);
1771         } else {
1772                 kfree_skb(skb);
1773                 ppp_receive_error(ppp);
1774         }
1775 }
1776
1777 static void
1778 ppp_receive_error(struct ppp *ppp)
1779 {
1780         ++ppp->dev->stats.rx_errors;
1781         if (ppp->vj)
1782                 slhc_toss(ppp->vj);
1783 }
1784
1785 static void
1786 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1787 {
1788         struct sk_buff *ns;
1789         int proto, len, npi;
1790
1791         /*
1792          * Decompress the frame, if compressed.
1793          * Note that some decompressors need to see uncompressed frames
1794          * that come in as well as compressed frames.
1795          */
1796         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1797             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1798                 skb = ppp_decompress_frame(ppp, skb);
1799
1800         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1801                 goto err;
1802
1803         proto = PPP_PROTO(skb);
1804         switch (proto) {
1805         case PPP_VJC_COMP:
1806                 /* decompress VJ compressed packets */
1807                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1808                         goto err;
1809
1810                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1811                         /* copy to a new sk_buff with more tailroom */
1812                         ns = dev_alloc_skb(skb->len + 128);
1813                         if (!ns) {
1814                                 netdev_err(ppp->dev, "PPP: no memory "
1815                                            "(VJ decomp)\n");
1816                                 goto err;
1817                         }
1818                         skb_reserve(ns, 2);
1819                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1820                         consume_skb(skb);
1821                         skb = ns;
1822                 }
1823                 else
1824                         skb->ip_summed = CHECKSUM_NONE;
1825
1826                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1827                 if (len <= 0) {
1828                         netdev_printk(KERN_DEBUG, ppp->dev,
1829                                       "PPP: VJ decompression error\n");
1830                         goto err;
1831                 }
1832                 len += 2;
1833                 if (len > skb->len)
1834                         skb_put(skb, len - skb->len);
1835                 else if (len < skb->len)
1836                         skb_trim(skb, len);
1837                 proto = PPP_IP;
1838                 break;
1839
1840         case PPP_VJC_UNCOMP:
1841                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1842                         goto err;
1843
1844                 /* Until we fix the decompressor need to make sure
1845                  * data portion is linear.
1846                  */
1847                 if (!pskb_may_pull(skb, skb->len))
1848                         goto err;
1849
1850                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1851                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1852                         goto err;
1853                 }
1854                 proto = PPP_IP;
1855                 break;
1856
1857         case PPP_CCP:
1858                 ppp_ccp_peek(ppp, skb, 1);
1859                 break;
1860         }
1861
1862         ++ppp->stats64.rx_packets;
1863         ppp->stats64.rx_bytes += skb->len - 2;
1864
1865         npi = proto_to_npindex(proto);
1866         if (npi < 0) {
1867                 /* control or unknown frame - pass it to pppd */
1868                 skb_queue_tail(&ppp->file.rq, skb);
1869                 /* limit queue length by dropping old frames */
1870                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1871                        (skb = skb_dequeue(&ppp->file.rq)))
1872                         kfree_skb(skb);
1873                 /* wake up any process polling or blocking on read */
1874                 wake_up_interruptible(&ppp->file.rwait);
1875
1876         } else {
1877                 /* network protocol frame - give it to the kernel */
1878
1879 #ifdef CONFIG_PPP_FILTER
1880                 /* check if the packet passes the pass and active filters */
1881                 /* the filter instructions are constructed assuming
1882                    a four-byte PPP header on each packet */
1883                 if (ppp->pass_filter || ppp->active_filter) {
1884                         if (skb_unclone(skb, GFP_ATOMIC))
1885                                 goto err;
1886
1887                         *skb_push(skb, 2) = 0;
1888                         if (ppp->pass_filter &&
1889                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1890                                 if (ppp->debug & 1)
1891                                         netdev_printk(KERN_DEBUG, ppp->dev,
1892                                                       "PPP: inbound frame "
1893                                                       "not passed\n");
1894                                 kfree_skb(skb);
1895                                 return;
1896                         }
1897                         if (!(ppp->active_filter &&
1898                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1899                                 ppp->last_recv = jiffies;
1900                         __skb_pull(skb, 2);
1901                 } else
1902 #endif /* CONFIG_PPP_FILTER */
1903                         ppp->last_recv = jiffies;
1904
1905                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1906                     ppp->npmode[npi] != NPMODE_PASS) {
1907                         kfree_skb(skb);
1908                 } else {
1909                         /* chop off protocol */
1910                         skb_pull_rcsum(skb, 2);
1911                         skb->dev = ppp->dev;
1912                         skb->protocol = htons(npindex_to_ethertype[npi]);
1913                         skb_reset_mac_header(skb);
1914                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
1915                                                       dev_net(ppp->dev)));
1916                         netif_rx(skb);
1917                 }
1918         }
1919         return;
1920
1921  err:
1922         kfree_skb(skb);
1923         ppp_receive_error(ppp);
1924 }
1925
1926 static struct sk_buff *
1927 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1928 {
1929         int proto = PPP_PROTO(skb);
1930         struct sk_buff *ns;
1931         int len;
1932
1933         /* Until we fix all the decompressor's need to make sure
1934          * data portion is linear.
1935          */
1936         if (!pskb_may_pull(skb, skb->len))
1937                 goto err;
1938
1939         if (proto == PPP_COMP) {
1940                 int obuff_size;
1941
1942                 switch(ppp->rcomp->compress_proto) {
1943                 case CI_MPPE:
1944                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1945                         break;
1946                 default:
1947                         obuff_size = ppp->mru + PPP_HDRLEN;
1948                         break;
1949                 }
1950
1951                 ns = dev_alloc_skb(obuff_size);
1952                 if (!ns) {
1953                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1954                                    "no memory\n");
1955                         goto err;
1956                 }
1957                 /* the decompressor still expects the A/C bytes in the hdr */
1958                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1959                                 skb->len + 2, ns->data, obuff_size);
1960                 if (len < 0) {
1961                         /* Pass the compressed frame to pppd as an
1962                            error indication. */
1963                         if (len == DECOMP_FATALERROR)
1964                                 ppp->rstate |= SC_DC_FERROR;
1965                         kfree_skb(ns);
1966                         goto err;
1967                 }
1968
1969                 consume_skb(skb);
1970                 skb = ns;
1971                 skb_put(skb, len);
1972                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1973
1974         } else {
1975                 /* Uncompressed frame - pass to decompressor so it
1976                    can update its dictionary if necessary. */
1977                 if (ppp->rcomp->incomp)
1978                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1979                                            skb->len + 2);
1980         }
1981
1982         return skb;
1983
1984  err:
1985         ppp->rstate |= SC_DC_ERROR;
1986         ppp_receive_error(ppp);
1987         return skb;
1988 }
1989
1990 #ifdef CONFIG_PPP_MULTILINK
1991 /*
1992  * Receive a multilink frame.
1993  * We put it on the reconstruction queue and then pull off
1994  * as many completed frames as we can.
1995  */
1996 static void
1997 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1998 {
1999         u32 mask, seq;
2000         struct channel *ch;
2001         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2002
2003         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2004                 goto err;               /* no good, throw it away */
2005
2006         /* Decode sequence number and begin/end bits */
2007         if (ppp->flags & SC_MP_SHORTSEQ) {
2008                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2009                 mask = 0xfff;
2010         } else {
2011                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2012                 mask = 0xffffff;
2013         }
2014         PPP_MP_CB(skb)->BEbits = skb->data[2];
2015         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2016
2017         /*
2018          * Do protocol ID decompression on the first fragment of each packet.
2019          */
2020         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2021                 *skb_push(skb, 1) = 0;
2022
2023         /*
2024          * Expand sequence number to 32 bits, making it as close
2025          * as possible to ppp->minseq.
2026          */
2027         seq |= ppp->minseq & ~mask;
2028         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2029                 seq += mask + 1;
2030         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2031                 seq -= mask + 1;        /* should never happen */
2032         PPP_MP_CB(skb)->sequence = seq;
2033         pch->lastseq = seq;
2034
2035         /*
2036          * If this packet comes before the next one we were expecting,
2037          * drop it.
2038          */
2039         if (seq_before(seq, ppp->nextseq)) {
2040                 kfree_skb(skb);
2041                 ++ppp->dev->stats.rx_dropped;
2042                 ppp_receive_error(ppp);
2043                 return;
2044         }
2045
2046         /*
2047          * Reevaluate minseq, the minimum over all channels of the
2048          * last sequence number received on each channel.  Because of
2049          * the increasing sequence number rule, we know that any fragment
2050          * before `minseq' which hasn't arrived is never going to arrive.
2051          * The list of channels can't change because we have the receive
2052          * side of the ppp unit locked.
2053          */
2054         list_for_each_entry(ch, &ppp->channels, clist) {
2055                 if (seq_before(ch->lastseq, seq))
2056                         seq = ch->lastseq;
2057         }
2058         if (seq_before(ppp->minseq, seq))
2059                 ppp->minseq = seq;
2060
2061         /* Put the fragment on the reconstruction queue */
2062         ppp_mp_insert(ppp, skb);
2063
2064         /* If the queue is getting long, don't wait any longer for packets
2065            before the start of the queue. */
2066         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2067                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2068                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2069                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2070         }
2071
2072         /* Pull completed packets off the queue and receive them. */
2073         while ((skb = ppp_mp_reconstruct(ppp))) {
2074                 if (pskb_may_pull(skb, 2))
2075                         ppp_receive_nonmp_frame(ppp, skb);
2076                 else {
2077                         ++ppp->dev->stats.rx_length_errors;
2078                         kfree_skb(skb);
2079                         ppp_receive_error(ppp);
2080                 }
2081         }
2082
2083         return;
2084
2085  err:
2086         kfree_skb(skb);
2087         ppp_receive_error(ppp);
2088 }
2089
2090 /*
2091  * Insert a fragment on the MP reconstruction queue.
2092  * The queue is ordered by increasing sequence number.
2093  */
2094 static void
2095 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2096 {
2097         struct sk_buff *p;
2098         struct sk_buff_head *list = &ppp->mrq;
2099         u32 seq = PPP_MP_CB(skb)->sequence;
2100
2101         /* N.B. we don't need to lock the list lock because we have the
2102            ppp unit receive-side lock. */
2103         skb_queue_walk(list, p) {
2104                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2105                         break;
2106         }
2107         __skb_queue_before(list, p, skb);
2108 }
2109
2110 /*
2111  * Reconstruct a packet from the MP fragment queue.
2112  * We go through increasing sequence numbers until we find a
2113  * complete packet, or we get to the sequence number for a fragment
2114  * which hasn't arrived but might still do so.
2115  */
2116 static struct sk_buff *
2117 ppp_mp_reconstruct(struct ppp *ppp)
2118 {
2119         u32 seq = ppp->nextseq;
2120         u32 minseq = ppp->minseq;
2121         struct sk_buff_head *list = &ppp->mrq;
2122         struct sk_buff *p, *tmp;
2123         struct sk_buff *head, *tail;
2124         struct sk_buff *skb = NULL;
2125         int lost = 0, len = 0;
2126
2127         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2128                 return NULL;
2129         head = list->next;
2130         tail = NULL;
2131         skb_queue_walk_safe(list, p, tmp) {
2132         again:
2133                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2134                         /* this can't happen, anyway ignore the skb */
2135                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2136                                    "seq %u < %u\n",
2137                                    PPP_MP_CB(p)->sequence, seq);
2138                         __skb_unlink(p, list);
2139                         kfree_skb(p);
2140                         continue;
2141                 }
2142                 if (PPP_MP_CB(p)->sequence != seq) {
2143                         u32 oldseq;
2144                         /* Fragment `seq' is missing.  If it is after
2145                            minseq, it might arrive later, so stop here. */
2146                         if (seq_after(seq, minseq))
2147                                 break;
2148                         /* Fragment `seq' is lost, keep going. */
2149                         lost = 1;
2150                         oldseq = seq;
2151                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2152                                 minseq + 1: PPP_MP_CB(p)->sequence;
2153
2154                         if (ppp->debug & 1)
2155                                 netdev_printk(KERN_DEBUG, ppp->dev,
2156                                               "lost frag %u..%u\n",
2157                                               oldseq, seq-1);
2158
2159                         goto again;
2160                 }
2161
2162                 /*
2163                  * At this point we know that all the fragments from
2164                  * ppp->nextseq to seq are either present or lost.
2165                  * Also, there are no complete packets in the queue
2166                  * that have no missing fragments and end before this
2167                  * fragment.
2168                  */
2169
2170                 /* B bit set indicates this fragment starts a packet */
2171                 if (PPP_MP_CB(p)->BEbits & B) {
2172                         head = p;
2173                         lost = 0;
2174                         len = 0;
2175                 }
2176
2177                 len += p->len;
2178
2179                 /* Got a complete packet yet? */
2180                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2181                     (PPP_MP_CB(head)->BEbits & B)) {
2182                         if (len > ppp->mrru + 2) {
2183                                 ++ppp->dev->stats.rx_length_errors;
2184                                 netdev_printk(KERN_DEBUG, ppp->dev,
2185                                               "PPP: reconstructed packet"
2186                                               " is too long (%d)\n", len);
2187                         } else {
2188                                 tail = p;
2189                                 break;
2190                         }
2191                         ppp->nextseq = seq + 1;
2192                 }
2193
2194                 /*
2195                  * If this is the ending fragment of a packet,
2196                  * and we haven't found a complete valid packet yet,
2197                  * we can discard up to and including this fragment.
2198                  */
2199                 if (PPP_MP_CB(p)->BEbits & E) {
2200                         struct sk_buff *tmp2;
2201
2202                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2203                                 if (ppp->debug & 1)
2204                                         netdev_printk(KERN_DEBUG, ppp->dev,
2205                                                       "discarding frag %u\n",
2206                                                       PPP_MP_CB(p)->sequence);
2207                                 __skb_unlink(p, list);
2208                                 kfree_skb(p);
2209                         }
2210                         head = skb_peek(list);
2211                         if (!head)
2212                                 break;
2213                 }
2214                 ++seq;
2215         }
2216
2217         /* If we have a complete packet, copy it all into one skb. */
2218         if (tail != NULL) {
2219                 /* If we have discarded any fragments,
2220                    signal a receive error. */
2221                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2222                         skb_queue_walk_safe(list, p, tmp) {
2223                                 if (p == head)
2224                                         break;
2225                                 if (ppp->debug & 1)
2226                                         netdev_printk(KERN_DEBUG, ppp->dev,
2227                                                       "discarding frag %u\n",
2228                                                       PPP_MP_CB(p)->sequence);
2229                                 __skb_unlink(p, list);
2230                                 kfree_skb(p);
2231                         }
2232
2233                         if (ppp->debug & 1)
2234                                 netdev_printk(KERN_DEBUG, ppp->dev,
2235                                               "  missed pkts %u..%u\n",
2236                                               ppp->nextseq,
2237                                               PPP_MP_CB(head)->sequence-1);
2238                         ++ppp->dev->stats.rx_dropped;
2239                         ppp_receive_error(ppp);
2240                 }
2241
2242                 skb = head;
2243                 if (head != tail) {
2244                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2245                         p = skb_queue_next(list, head);
2246                         __skb_unlink(skb, list);
2247                         skb_queue_walk_from_safe(list, p, tmp) {
2248                                 __skb_unlink(p, list);
2249                                 *fragpp = p;
2250                                 p->next = NULL;
2251                                 fragpp = &p->next;
2252
2253                                 skb->len += p->len;
2254                                 skb->data_len += p->len;
2255                                 skb->truesize += p->truesize;
2256
2257                                 if (p == tail)
2258                                         break;
2259                         }
2260                 } else {
2261                         __skb_unlink(skb, list);
2262                 }
2263
2264                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2265         }
2266
2267         return skb;
2268 }
2269 #endif /* CONFIG_PPP_MULTILINK */
2270
2271 /*
2272  * Channel interface.
2273  */
2274
2275 /* Create a new, unattached ppp channel. */
2276 int ppp_register_channel(struct ppp_channel *chan)
2277 {
2278         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2279 }
2280
2281 /* Create a new, unattached ppp channel for specified net. */
2282 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2283 {
2284         struct channel *pch;
2285         struct ppp_net *pn;
2286
2287         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2288         if (!pch)
2289                 return -ENOMEM;
2290
2291         pn = ppp_pernet(net);
2292
2293         pch->ppp = NULL;
2294         pch->chan = chan;
2295         pch->chan_net = net;
2296         chan->ppp = pch;
2297         init_ppp_file(&pch->file, CHANNEL);
2298         pch->file.hdrlen = chan->hdrlen;
2299 #ifdef CONFIG_PPP_MULTILINK
2300         pch->lastseq = -1;
2301 #endif /* CONFIG_PPP_MULTILINK */
2302         init_rwsem(&pch->chan_sem);
2303         spin_lock_init(&pch->downl);
2304         rwlock_init(&pch->upl);
2305
2306         spin_lock_bh(&pn->all_channels_lock);
2307         pch->file.index = ++pn->last_channel_index;
2308         list_add(&pch->list, &pn->new_channels);
2309         atomic_inc(&channel_count);
2310         spin_unlock_bh(&pn->all_channels_lock);
2311
2312         return 0;
2313 }
2314
2315 /*
2316  * Return the index of a channel.
2317  */
2318 int ppp_channel_index(struct ppp_channel *chan)
2319 {
2320         struct channel *pch = chan->ppp;
2321
2322         if (pch)
2323                 return pch->file.index;
2324         return -1;
2325 }
2326
2327 /*
2328  * Return the PPP unit number to which a channel is connected.
2329  */
2330 int ppp_unit_number(struct ppp_channel *chan)
2331 {
2332         struct channel *pch = chan->ppp;
2333         int unit = -1;
2334
2335         if (pch) {
2336                 read_lock_bh(&pch->upl);
2337                 if (pch->ppp)
2338                         unit = pch->ppp->file.index;
2339                 read_unlock_bh(&pch->upl);
2340         }
2341         return unit;
2342 }
2343
2344 /*
2345  * Return the PPP device interface name of a channel.
2346  */
2347 char *ppp_dev_name(struct ppp_channel *chan)
2348 {
2349         struct channel *pch = chan->ppp;
2350         char *name = NULL;
2351
2352         if (pch) {
2353                 read_lock_bh(&pch->upl);
2354                 if (pch->ppp && pch->ppp->dev)
2355                         name = pch->ppp->dev->name;
2356                 read_unlock_bh(&pch->upl);
2357         }
2358         return name;
2359 }
2360
2361
2362 /*
2363  * Disconnect a channel from the generic layer.
2364  * This must be called in process context.
2365  */
2366 void
2367 ppp_unregister_channel(struct ppp_channel *chan)
2368 {
2369         struct channel *pch = chan->ppp;
2370         struct ppp_net *pn;
2371
2372         if (!pch)
2373                 return;         /* should never happen */
2374
2375         chan->ppp = NULL;
2376
2377         /*
2378          * This ensures that we have returned from any calls into the
2379          * the channel's start_xmit or ioctl routine before we proceed.
2380          */
2381         down_write(&pch->chan_sem);
2382         spin_lock_bh(&pch->downl);
2383         pch->chan = NULL;
2384         spin_unlock_bh(&pch->downl);
2385         up_write(&pch->chan_sem);
2386         ppp_disconnect_channel(pch);
2387
2388         pn = ppp_pernet(pch->chan_net);
2389         spin_lock_bh(&pn->all_channels_lock);
2390         list_del(&pch->list);
2391         spin_unlock_bh(&pn->all_channels_lock);
2392
2393         pch->file.dead = 1;
2394         wake_up_interruptible(&pch->file.rwait);
2395         if (atomic_dec_and_test(&pch->file.refcnt))
2396                 ppp_destroy_channel(pch);
2397 }
2398
2399 /*
2400  * Callback from a channel when it can accept more to transmit.
2401  * This should be called at BH/softirq level, not interrupt level.
2402  */
2403 void
2404 ppp_output_wakeup(struct ppp_channel *chan)
2405 {
2406         struct channel *pch = chan->ppp;
2407
2408         if (!pch)
2409                 return;
2410         ppp_channel_push(pch);
2411 }
2412
2413 /*
2414  * Compression control.
2415  */
2416
2417 /* Process the PPPIOCSCOMPRESS ioctl. */
2418 static int
2419 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2420 {
2421         int err;
2422         struct compressor *cp, *ocomp;
2423         struct ppp_option_data data;
2424         void *state, *ostate;
2425         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2426
2427         err = -EFAULT;
2428         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2429             (data.length <= CCP_MAX_OPTION_LENGTH &&
2430              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2431                 goto out;
2432         err = -EINVAL;
2433         if (data.length > CCP_MAX_OPTION_LENGTH ||
2434             ccp_option[1] < 2 || ccp_option[1] > data.length)
2435                 goto out;
2436
2437         cp = try_then_request_module(
2438                 find_compressor(ccp_option[0]),
2439                 "ppp-compress-%d", ccp_option[0]);
2440         if (!cp)
2441                 goto out;
2442
2443         err = -ENOBUFS;
2444         if (data.transmit) {
2445                 state = cp->comp_alloc(ccp_option, data.length);
2446                 if (state) {
2447                         ppp_xmit_lock(ppp);
2448                         ppp->xstate &= ~SC_COMP_RUN;
2449                         ocomp = ppp->xcomp;
2450                         ostate = ppp->xc_state;
2451                         ppp->xcomp = cp;
2452                         ppp->xc_state = state;
2453                         ppp_xmit_unlock(ppp);
2454                         if (ostate) {
2455                                 ocomp->comp_free(ostate);
2456                                 module_put(ocomp->owner);
2457                         }
2458                         err = 0;
2459                 } else
2460                         module_put(cp->owner);
2461
2462         } else {
2463                 state = cp->decomp_alloc(ccp_option, data.length);
2464                 if (state) {
2465                         ppp_recv_lock(ppp);
2466                         ppp->rstate &= ~SC_DECOMP_RUN;
2467                         ocomp = ppp->rcomp;
2468                         ostate = ppp->rc_state;
2469                         ppp->rcomp = cp;
2470                         ppp->rc_state = state;
2471                         ppp_recv_unlock(ppp);
2472                         if (ostate) {
2473                                 ocomp->decomp_free(ostate);
2474                                 module_put(ocomp->owner);
2475                         }
2476                         err = 0;
2477                 } else
2478                         module_put(cp->owner);
2479         }
2480
2481  out:
2482         return err;
2483 }
2484
2485 /*
2486  * Look at a CCP packet and update our state accordingly.
2487  * We assume the caller has the xmit or recv path locked.
2488  */
2489 static void
2490 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2491 {
2492         unsigned char *dp;
2493         int len;
2494
2495         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2496                 return; /* no header */
2497         dp = skb->data + 2;
2498
2499         switch (CCP_CODE(dp)) {
2500         case CCP_CONFREQ:
2501
2502                 /* A ConfReq starts negotiation of compression
2503                  * in one direction of transmission,
2504                  * and hence brings it down...but which way?
2505                  *
2506                  * Remember:
2507                  * A ConfReq indicates what the sender would like to receive
2508                  */
2509                 if(inbound)
2510                         /* He is proposing what I should send */
2511                         ppp->xstate &= ~SC_COMP_RUN;
2512                 else
2513                         /* I am proposing to what he should send */
2514                         ppp->rstate &= ~SC_DECOMP_RUN;
2515
2516                 break;
2517
2518         case CCP_TERMREQ:
2519         case CCP_TERMACK:
2520                 /*
2521                  * CCP is going down, both directions of transmission
2522                  */
2523                 ppp->rstate &= ~SC_DECOMP_RUN;
2524                 ppp->xstate &= ~SC_COMP_RUN;
2525                 break;
2526
2527         case CCP_CONFACK:
2528                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2529                         break;
2530                 len = CCP_LENGTH(dp);
2531                 if (!pskb_may_pull(skb, len + 2))
2532                         return;         /* too short */
2533                 dp += CCP_HDRLEN;
2534                 len -= CCP_HDRLEN;
2535                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2536                         break;
2537                 if (inbound) {
2538                         /* we will start receiving compressed packets */
2539                         if (!ppp->rc_state)
2540                                 break;
2541                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2542                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2543                                 ppp->rstate |= SC_DECOMP_RUN;
2544                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2545                         }
2546                 } else {
2547                         /* we will soon start sending compressed packets */
2548                         if (!ppp->xc_state)
2549                                 break;
2550                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2551                                         ppp->file.index, 0, ppp->debug))
2552                                 ppp->xstate |= SC_COMP_RUN;
2553                 }
2554                 break;
2555
2556         case CCP_RESETACK:
2557                 /* reset the [de]compressor */
2558                 if ((ppp->flags & SC_CCP_UP) == 0)
2559                         break;
2560                 if (inbound) {
2561                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2562                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2563                                 ppp->rstate &= ~SC_DC_ERROR;
2564                         }
2565                 } else {
2566                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2567                                 ppp->xcomp->comp_reset(ppp->xc_state);
2568                 }
2569                 break;
2570         }
2571 }
2572
2573 /* Free up compression resources. */
2574 static void
2575 ppp_ccp_closed(struct ppp *ppp)
2576 {
2577         void *xstate, *rstate;
2578         struct compressor *xcomp, *rcomp;
2579
2580         ppp_lock(ppp);
2581         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2582         ppp->xstate = 0;
2583         xcomp = ppp->xcomp;
2584         xstate = ppp->xc_state;
2585         ppp->xc_state = NULL;
2586         ppp->rstate = 0;
2587         rcomp = ppp->rcomp;
2588         rstate = ppp->rc_state;
2589         ppp->rc_state = NULL;
2590         ppp_unlock(ppp);
2591
2592         if (xstate) {
2593                 xcomp->comp_free(xstate);
2594                 module_put(xcomp->owner);
2595         }
2596         if (rstate) {
2597                 rcomp->decomp_free(rstate);
2598                 module_put(rcomp->owner);
2599         }
2600 }
2601
2602 /* List of compressors. */
2603 static LIST_HEAD(compressor_list);
2604 static DEFINE_SPINLOCK(compressor_list_lock);
2605
2606 struct compressor_entry {
2607         struct list_head list;
2608         struct compressor *comp;
2609 };
2610
2611 static struct compressor_entry *
2612 find_comp_entry(int proto)
2613 {
2614         struct compressor_entry *ce;
2615
2616         list_for_each_entry(ce, &compressor_list, list) {
2617                 if (ce->comp->compress_proto == proto)
2618                         return ce;
2619         }
2620         return NULL;
2621 }
2622
2623 /* Register a compressor */
2624 int
2625 ppp_register_compressor(struct compressor *cp)
2626 {
2627         struct compressor_entry *ce;
2628         int ret;
2629         spin_lock(&compressor_list_lock);
2630         ret = -EEXIST;
2631         if (find_comp_entry(cp->compress_proto))
2632                 goto out;
2633         ret = -ENOMEM;
2634         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2635         if (!ce)
2636                 goto out;
2637         ret = 0;
2638         ce->comp = cp;
2639         list_add(&ce->list, &compressor_list);
2640  out:
2641         spin_unlock(&compressor_list_lock);
2642         return ret;
2643 }
2644
2645 /* Unregister a compressor */
2646 void
2647 ppp_unregister_compressor(struct compressor *cp)
2648 {
2649         struct compressor_entry *ce;
2650
2651         spin_lock(&compressor_list_lock);
2652         ce = find_comp_entry(cp->compress_proto);
2653         if (ce && ce->comp == cp) {
2654                 list_del(&ce->list);
2655                 kfree(ce);
2656         }
2657         spin_unlock(&compressor_list_lock);
2658 }
2659
2660 /* Find a compressor. */
2661 static struct compressor *
2662 find_compressor(int type)
2663 {
2664         struct compressor_entry *ce;
2665         struct compressor *cp = NULL;
2666
2667         spin_lock(&compressor_list_lock);
2668         ce = find_comp_entry(type);
2669         if (ce) {
2670                 cp = ce->comp;
2671                 if (!try_module_get(cp->owner))
2672                         cp = NULL;
2673         }
2674         spin_unlock(&compressor_list_lock);
2675         return cp;
2676 }
2677
2678 /*
2679  * Miscelleneous stuff.
2680  */
2681
2682 static void
2683 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2684 {
2685         struct slcompress *vj = ppp->vj;
2686
2687         memset(st, 0, sizeof(*st));
2688         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2689         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2690         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2691         st->p.ppp_opackets = ppp->stats64.tx_packets;
2692         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2693         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2694         if (!vj)
2695                 return;
2696         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2697         st->vj.vjs_compressed = vj->sls_o_compressed;
2698         st->vj.vjs_searches = vj->sls_o_searches;
2699         st->vj.vjs_misses = vj->sls_o_misses;
2700         st->vj.vjs_errorin = vj->sls_i_error;
2701         st->vj.vjs_tossed = vj->sls_i_tossed;
2702         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2703         st->vj.vjs_compressedin = vj->sls_i_compressed;
2704 }
2705
2706 /*
2707  * Stuff for handling the lists of ppp units and channels
2708  * and for initialization.
2709  */
2710
2711 /*
2712  * Create a new ppp interface unit.  Fails if it can't allocate memory
2713  * or if there is already a unit with the requested number.
2714  * unit == -1 means allocate a new number.
2715  */
2716 static struct ppp *ppp_create_interface(struct net *net, int unit,
2717                                         struct file *file, int *retp)
2718 {
2719         struct ppp *ppp;
2720         struct ppp_net *pn;
2721         struct net_device *dev = NULL;
2722         int ret = -ENOMEM;
2723         int i;
2724
2725         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_UNKNOWN,
2726                            ppp_setup);
2727         if (!dev)
2728                 goto out1;
2729
2730         pn = ppp_pernet(net);
2731
2732         ppp = netdev_priv(dev);
2733         ppp->dev = dev;
2734         ppp->mru = PPP_MRU;
2735         init_ppp_file(&ppp->file, INTERFACE);
2736         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2737         ppp->owner = file;
2738         for (i = 0; i < NUM_NP; ++i)
2739                 ppp->npmode[i] = NPMODE_PASS;
2740         INIT_LIST_HEAD(&ppp->channels);
2741         spin_lock_init(&ppp->rlock);
2742         spin_lock_init(&ppp->wlock);
2743 #ifdef CONFIG_PPP_MULTILINK
2744         ppp->minseq = -1;
2745         skb_queue_head_init(&ppp->mrq);
2746 #endif /* CONFIG_PPP_MULTILINK */
2747 #ifdef CONFIG_PPP_FILTER
2748         ppp->pass_filter = NULL;
2749         ppp->active_filter = NULL;
2750 #endif /* CONFIG_PPP_FILTER */
2751
2752         /*
2753          * drum roll: don't forget to set
2754          * the net device is belong to
2755          */
2756         dev_net_set(dev, net);
2757
2758         rtnl_lock();
2759         mutex_lock(&pn->all_ppp_mutex);
2760
2761         if (unit < 0) {
2762                 unit = unit_get(&pn->units_idr, ppp);
2763                 if (unit < 0) {
2764                         ret = unit;
2765                         goto out2;
2766                 }
2767         } else {
2768                 ret = -EEXIST;
2769                 if (unit_find(&pn->units_idr, unit))
2770                         goto out2; /* unit already exists */
2771                 /*
2772                  * if caller need a specified unit number
2773                  * lets try to satisfy him, otherwise --
2774                  * he should better ask us for new unit number
2775                  *
2776                  * NOTE: yes I know that returning EEXIST it's not
2777                  * fair but at least pppd will ask us to allocate
2778                  * new unit in this case so user is happy :)
2779                  */
2780                 unit = unit_set(&pn->units_idr, ppp, unit);
2781                 if (unit < 0)
2782                         goto out2;
2783         }
2784
2785         /* Initialize the new ppp unit */
2786         ppp->file.index = unit;
2787         sprintf(dev->name, "ppp%d", unit);
2788
2789         ret = register_netdevice(dev);
2790         if (ret != 0) {
2791                 unit_put(&pn->units_idr, unit);
2792                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2793                            dev->name, ret);
2794                 goto out2;
2795         }
2796
2797         ppp->ppp_net = net;
2798
2799         atomic_inc(&ppp_unit_count);
2800         mutex_unlock(&pn->all_ppp_mutex);
2801         rtnl_unlock();
2802
2803         *retp = 0;
2804         return ppp;
2805
2806 out2:
2807         mutex_unlock(&pn->all_ppp_mutex);
2808         free_netdev(dev);
2809 out1:
2810         *retp = ret;
2811         return NULL;
2812 }
2813
2814 /*
2815  * Initialize a ppp_file structure.
2816  */
2817 static void
2818 init_ppp_file(struct ppp_file *pf, int kind)
2819 {
2820         pf->kind = kind;
2821         skb_queue_head_init(&pf->xq);
2822         skb_queue_head_init(&pf->rq);
2823         atomic_set(&pf->refcnt, 1);
2824         init_waitqueue_head(&pf->rwait);
2825 }
2826
2827 /*
2828  * Free the memory used by a ppp unit.  This is only called once
2829  * there are no channels connected to the unit and no file structs
2830  * that reference the unit.
2831  */
2832 static void ppp_destroy_interface(struct ppp *ppp)
2833 {
2834         atomic_dec(&ppp_unit_count);
2835
2836         if (!ppp->file.dead || ppp->n_channels) {
2837                 /* "can't happen" */
2838                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2839                            "but dead=%d n_channels=%d !\n",
2840                            ppp, ppp->file.dead, ppp->n_channels);
2841                 return;
2842         }
2843
2844         ppp_ccp_closed(ppp);
2845         if (ppp->vj) {
2846                 slhc_free(ppp->vj);
2847                 ppp->vj = NULL;
2848         }
2849         skb_queue_purge(&ppp->file.xq);
2850         skb_queue_purge(&ppp->file.rq);
2851 #ifdef CONFIG_PPP_MULTILINK
2852         skb_queue_purge(&ppp->mrq);
2853 #endif /* CONFIG_PPP_MULTILINK */
2854 #ifdef CONFIG_PPP_FILTER
2855         if (ppp->pass_filter) {
2856                 bpf_prog_destroy(ppp->pass_filter);
2857                 ppp->pass_filter = NULL;
2858         }
2859
2860         if (ppp->active_filter) {
2861                 bpf_prog_destroy(ppp->active_filter);
2862                 ppp->active_filter = NULL;
2863         }
2864 #endif /* CONFIG_PPP_FILTER */
2865
2866         kfree_skb(ppp->xmit_pending);
2867
2868         free_netdev(ppp->dev);
2869 }
2870
2871 /*
2872  * Locate an existing ppp unit.
2873  * The caller should have locked the all_ppp_mutex.
2874  */
2875 static struct ppp *
2876 ppp_find_unit(struct ppp_net *pn, int unit)
2877 {
2878         return unit_find(&pn->units_idr, unit);
2879 }
2880
2881 /*
2882  * Locate an existing ppp channel.
2883  * The caller should have locked the all_channels_lock.
2884  * First we look in the new_channels list, then in the
2885  * all_channels list.  If found in the new_channels list,
2886  * we move it to the all_channels list.  This is for speed
2887  * when we have a lot of channels in use.
2888  */
2889 static struct channel *
2890 ppp_find_channel(struct ppp_net *pn, int unit)
2891 {
2892         struct channel *pch;
2893
2894         list_for_each_entry(pch, &pn->new_channels, list) {
2895                 if (pch->file.index == unit) {
2896                         list_move(&pch->list, &pn->all_channels);
2897                         return pch;
2898                 }
2899         }
2900
2901         list_for_each_entry(pch, &pn->all_channels, list) {
2902                 if (pch->file.index == unit)
2903                         return pch;
2904         }
2905
2906         return NULL;
2907 }
2908
2909 /*
2910  * Connect a PPP channel to a PPP interface unit.
2911  */
2912 static int
2913 ppp_connect_channel(struct channel *pch, int unit)
2914 {
2915         struct ppp *ppp;
2916         struct ppp_net *pn;
2917         int ret = -ENXIO;
2918         int hdrlen;
2919
2920         pn = ppp_pernet(pch->chan_net);
2921
2922         mutex_lock(&pn->all_ppp_mutex);
2923         ppp = ppp_find_unit(pn, unit);
2924         if (!ppp)
2925                 goto out;
2926         write_lock_bh(&pch->upl);
2927         ret = -EINVAL;
2928         if (pch->ppp)
2929                 goto outl;
2930
2931         ppp_lock(ppp);
2932         if (pch->file.hdrlen > ppp->file.hdrlen)
2933                 ppp->file.hdrlen = pch->file.hdrlen;
2934         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2935         if (hdrlen > ppp->dev->hard_header_len)
2936                 ppp->dev->hard_header_len = hdrlen;
2937         list_add_tail(&pch->clist, &ppp->channels);
2938         ++ppp->n_channels;
2939         pch->ppp = ppp;
2940         atomic_inc(&ppp->file.refcnt);
2941         ppp_unlock(ppp);
2942         ret = 0;
2943
2944  outl:
2945         write_unlock_bh(&pch->upl);
2946  out:
2947         mutex_unlock(&pn->all_ppp_mutex);
2948         return ret;
2949 }
2950
2951 /*
2952  * Disconnect a channel from its ppp unit.
2953  */
2954 static int
2955 ppp_disconnect_channel(struct channel *pch)
2956 {
2957         struct ppp *ppp;
2958         int err = -EINVAL;
2959
2960         write_lock_bh(&pch->upl);
2961         ppp = pch->ppp;
2962         pch->ppp = NULL;
2963         write_unlock_bh(&pch->upl);
2964         if (ppp) {
2965                 /* remove it from the ppp unit's list */
2966                 ppp_lock(ppp);
2967                 list_del(&pch->clist);
2968                 if (--ppp->n_channels == 0)
2969                         wake_up_interruptible(&ppp->file.rwait);
2970                 ppp_unlock(ppp);
2971                 if (atomic_dec_and_test(&ppp->file.refcnt))
2972                         ppp_destroy_interface(ppp);
2973                 err = 0;
2974         }
2975         return err;
2976 }
2977
2978 /*
2979  * Free up the resources used by a ppp channel.
2980  */
2981 static void ppp_destroy_channel(struct channel *pch)
2982 {
2983         atomic_dec(&channel_count);
2984
2985         if (!pch->file.dead) {
2986                 /* "can't happen" */
2987                 pr_err("ppp: destroying undead channel %p !\n", pch);
2988                 return;
2989         }
2990         skb_queue_purge(&pch->file.xq);
2991         skb_queue_purge(&pch->file.rq);
2992         kfree(pch);
2993 }
2994
2995 static void __exit ppp_cleanup(void)
2996 {
2997         /* should never happen */
2998         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2999                 pr_err("PPP: removing module but units remain!\n");
3000         unregister_chrdev(PPP_MAJOR, "ppp");
3001         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3002         class_destroy(ppp_class);
3003         unregister_pernet_device(&ppp_net_ops);
3004 }
3005
3006 /*
3007  * Units handling. Caller must protect concurrent access
3008  * by holding all_ppp_mutex
3009  */
3010
3011 /* associate pointer with specified number */
3012 static int unit_set(struct idr *p, void *ptr, int n)
3013 {
3014         int unit;
3015
3016         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3017         if (unit == -ENOSPC)
3018                 unit = -EINVAL;
3019         return unit;
3020 }
3021
3022 /* get new free unit number and associate pointer with it */
3023 static int unit_get(struct idr *p, void *ptr)
3024 {
3025         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3026 }
3027
3028 /* put unit number back to a pool */
3029 static void unit_put(struct idr *p, int n)
3030 {
3031         idr_remove(p, n);
3032 }
3033
3034 /* get pointer associated with the number */
3035 static void *unit_find(struct idr *p, int n)
3036 {
3037         return idr_find(p, n);
3038 }
3039
3040 /* Module/initialization stuff */
3041
3042 module_init(ppp_init);
3043 module_exit(ppp_cleanup);
3044
3045 EXPORT_SYMBOL(ppp_register_net_channel);
3046 EXPORT_SYMBOL(ppp_register_channel);
3047 EXPORT_SYMBOL(ppp_unregister_channel);
3048 EXPORT_SYMBOL(ppp_channel_index);
3049 EXPORT_SYMBOL(ppp_unit_number);
3050 EXPORT_SYMBOL(ppp_dev_name);
3051 EXPORT_SYMBOL(ppp_input);
3052 EXPORT_SYMBOL(ppp_input_error);
3053 EXPORT_SYMBOL(ppp_output_wakeup);
3054 EXPORT_SYMBOL(ppp_register_compressor);
3055 EXPORT_SYMBOL(ppp_unregister_compressor);
3056 MODULE_LICENSE("GPL");
3057 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3058 MODULE_ALIAS("devname:ppp");