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 <linux/file.h>
  50 #include <asm/unaligned.h>
  51 #include <net/slhc_vj.h>
  52 #include <linux/atomic.h>
  53
  54 #include <linux/nsproxy.h>
  55 #include <net/net_namespace.h>
  56 #include <net/netns/generic.h>
  57
  58 #define PPP_VERSION     "2.4.2"
  59
  60 /*
  61  * Network protocols we support.
  62  */
  63 #define NP_IP   0               /* Internet Protocol V4 */
  64 #define NP_IPV6 1               /* Internet Protocol V6 */
  65 #define NP_IPX  2               /* IPX protocol */
  66 #define NP_AT   3               /* Appletalk protocol */
  67 #define NP_MPLS_UC 4            /* MPLS unicast */
  68 #define NP_MPLS_MC 5            /* MPLS multicast */
  69 #define NUM_NP  6               /* Number of NPs. */
  70
  71 #define MPHDRLEN        6       /* multilink protocol header length */
  72 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  73
  74 /*
  75  * An instance of /dev/ppp can be associated with either a ppp
  76  * interface unit or a ppp channel.  In both cases, file->private_data
  77  * points to one of these.
  78  */
  79 struct ppp_file {
  80         enum {
  81                 INTERFACE=1, CHANNEL
  82         }               kind;
  83         struct sk_buff_head xq;         /* pppd transmit queue */
  84         struct sk_buff_head rq;         /* receive queue for pppd */
  85         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  86         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  87         int             hdrlen;         /* space to leave for headers */
  88         int             index;          /* interface unit / channel number */
  89         int             dead;           /* unit/channel has been shut down */
  90 };
  91
  92 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  93
  94 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  95 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  96
  97 /*
  98  * Data structure to hold primary network stats for which
  99  * we want to use 64 bit storage.  Other network stats
 100  * are stored in dev->stats of the ppp strucute.
 101  */
 102 struct ppp_link_stats {
 103         u64 rx_packets;
 104         u64 tx_packets;
 105         u64 rx_bytes;
 106         u64 tx_bytes;
 107 };
 108
 109 /*
 110  * Data structure describing one ppp unit.
 111  * A ppp unit corresponds to a ppp network interface device
 112  * and represents a multilink bundle.
 113  * It can have 0 or more ppp channels connected to it.
 114  */
 115 struct ppp {
 116         struct ppp_file file;           /* stuff for read/write/poll 0 */
 117         struct file     *owner;         /* file that owns this unit 48 */
 118         struct list_head channels;      /* list of attached channels 4c */
 119         int             n_channels;     /* how many channels are attached 54 */
 120         spinlock_t      rlock;          /* lock for receive side 58 */
 121         spinlock_t      wlock;          /* lock for transmit side 5c */
 122         int             *xmit_recursion __percpu; /* xmit recursion detect */
 123         int             mru;            /* max receive unit 60 */
 124         unsigned int    flags;          /* control bits 64 */
 125         unsigned int    xstate;         /* transmit state bits 68 */
 126         unsigned int    rstate;         /* receive state bits 6c */
 127         int             debug;          /* debug flags 70 */
 128         struct slcompress *vj;          /* state for VJ header compression */
 129         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 130         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 131         struct compressor *xcomp;       /* transmit packet compressor 8c */
 132         void            *xc_state;      /* its internal state 90 */
 133         struct compressor *rcomp;       /* receive decompressor 94 */
 134         void            *rc_state;      /* its internal state 98 */
 135         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 136         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 137         struct net_device *dev;         /* network interface device a4 */
 138         int             closing;        /* is device closing down? a8 */
 139 #ifdef CONFIG_PPP_MULTILINK
 140         int             nxchan;         /* next channel to send something on */
 141         u32             nxseq;          /* next sequence number to send */
 142         int             mrru;           /* MP: max reconst. receive unit */
 143         u32             nextseq;        /* MP: seq no of next packet */
 144         u32             minseq;         /* MP: min of most recent seqnos */
 145         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 146 #endif /* CONFIG_PPP_MULTILINK */
 147 #ifdef CONFIG_PPP_FILTER
 148         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 149         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 150 #endif /* CONFIG_PPP_FILTER */
 151         struct net      *ppp_net;       /* the net we belong to */
 152         struct ppp_link_stats stats64;  /* 64 bit network stats */
 153 };
 154
 155 /*
 156  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 157  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 158  * SC_MUST_COMP
 159  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 160  * Bits in xstate: SC_COMP_RUN
 161  */
 162 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 163                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 164                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 165
 166 /*
 167  * Private data structure for each channel.
 168  * This includes the data structure used for multilink.
 169  */
 170 struct channel {
 171         struct ppp_file file;           /* stuff for read/write/poll */
 172         struct list_head list;          /* link in all/new_channels list */
 173         struct ppp_channel *chan;       /* public channel data structure */
 174         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 175         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 176         struct ppp      *ppp;           /* ppp unit we're connected to */
 177         struct net      *chan_net;      /* the net channel belongs to */
 178         struct list_head clist;         /* link in list of channels per unit */
 179         rwlock_t        upl;            /* protects `ppp' */
 180 #ifdef CONFIG_PPP_MULTILINK
 181         u8              avail;          /* flag used in multilink stuff */
 182         u8              had_frag;       /* >= 1 fragments have been sent */
 183         u32             lastseq;        /* MP: last sequence # received */
 184         int             speed;          /* speed of the corresponding ppp channel*/
 185 #endif /* CONFIG_PPP_MULTILINK */
 186 };
 187
 188 struct ppp_config {
 189         struct file *file;
 190         s32 unit;
 191         bool ifname_is_set;
 192 };
 193
 194 /*
 195  * SMP locking issues:
 196  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 197  * list and the ppp.n_channels field, you need to take both locks
 198  * before you modify them.
 199  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 200  * channel.downl.
 201  */
 202
 203 static DEFINE_MUTEX(ppp_mutex);
 204 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 205 static atomic_t channel_count = ATOMIC_INIT(0);
 206
 207 /* per-net private data for this module */
 208 static int ppp_net_id __read_mostly;
 209 struct ppp_net {
 210         /* units to ppp mapping */
 211         struct idr units_idr;
 212
 213         /*
 214          * all_ppp_mutex protects the units_idr mapping.
 215          * It also ensures that finding a ppp unit in the units_idr
 216          * map and updating its file.refcnt field is atomic.
 217          */
 218         struct mutex all_ppp_mutex;
 219
 220         /* channels */
 221         struct list_head all_channels;
 222         struct list_head new_channels;
 223         int last_channel_index;
 224
 225         /*
 226          * all_channels_lock protects all_channels and
 227          * last_channel_index, and the atomicity of find
 228          * a channel and updating its file.refcnt field.
 229          */
 230         spinlock_t all_channels_lock;
 231 };
 232
 233 /* Get the PPP protocol number from a skb */
 234 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 235
 236 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 237 #define PPP_MAX_RQLEN   32
 238
 239 /*
 240  * Maximum number of multilink fragments queued up.
 241  * This has to be large enough to cope with the maximum latency of
 242  * the slowest channel relative to the others.  Strictly it should
 243  * depend on the number of channels and their characteristics.
 244  */
 245 #define PPP_MP_MAX_QLEN 128
 246
 247 /* Multilink header bits. */
 248 #define B       0x80            /* this fragment begins a packet */
 249 #define E       0x40            /* this fragment ends a packet */
 250
 251 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 252 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 253 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 254
 255 /* Prototypes. */
 256 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 257                         struct file *file, unsigned int cmd, unsigned long arg);
 258 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 259 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 260 static void ppp_push(struct ppp *ppp);
 261 static void ppp_channel_push(struct channel *pch);
 262 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 263                               struct channel *pch);
 264 static void ppp_receive_error(struct ppp *ppp);
 265 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 266 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 267                                             struct sk_buff *skb);
 268 #ifdef CONFIG_PPP_MULTILINK
 269 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 270                                 struct channel *pch);
 271 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 272 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 273 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 274 #endif /* CONFIG_PPP_MULTILINK */
 275 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 276 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 277 static void ppp_ccp_closed(struct ppp *ppp);
 278 static struct compressor *find_compressor(int type);
 279 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 280 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 281 static void init_ppp_file(struct ppp_file *pf, int kind);
 282 static void ppp_destroy_interface(struct ppp *ppp);
 283 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 284 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 285 static int ppp_connect_channel(struct channel *pch, int unit);
 286 static int ppp_disconnect_channel(struct channel *pch);
 287 static void ppp_destroy_channel(struct channel *pch);
 288 static int unit_get(struct idr *p, void *ptr, int min);
 289 static int unit_set(struct idr *p, void *ptr, int n);
 290 static void unit_put(struct idr *p, int n);
 291 static void *unit_find(struct idr *p, int n);
 292 static void ppp_setup(struct net_device *dev);
 293
 294 static const struct net_device_ops ppp_netdev_ops;
 295
 296 static struct class *ppp_class;
 297
 298 /* per net-namespace data */
 299 static inline struct ppp_net *ppp_pernet(struct net *net)
 300 {
 301         BUG_ON(!net);
 302
 303         return net_generic(net, ppp_net_id);
 304 }
 305
 306 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 307 static inline int proto_to_npindex(int proto)
 308 {
 309         switch (proto) {
 310         case PPP_IP:
 311                 return NP_IP;
 312         case PPP_IPV6:
 313                 return NP_IPV6;
 314         case PPP_IPX:
 315                 return NP_IPX;
 316         case PPP_AT:
 317                 return NP_AT;
 318         case PPP_MPLS_UC:
 319                 return NP_MPLS_UC;
 320         case PPP_MPLS_MC:
 321                 return NP_MPLS_MC;
 322         }
 323         return -EINVAL;
 324 }
 325
 326 /* Translates an NP index into a PPP protocol number */
 327 static const int npindex_to_proto[NUM_NP] = {
 328         PPP_IP,
 329         PPP_IPV6,
 330         PPP_IPX,
 331         PPP_AT,
 332         PPP_MPLS_UC,
 333         PPP_MPLS_MC,
 334 };
 335
 336 /* Translates an ethertype into an NP index */
 337 static inline int ethertype_to_npindex(int ethertype)
 338 {
 339         switch (ethertype) {
 340         case ETH_P_IP:
 341                 return NP_IP;
 342         case ETH_P_IPV6:
 343                 return NP_IPV6;
 344         case ETH_P_IPX:
 345                 return NP_IPX;
 346         case ETH_P_PPPTALK:
 347         case ETH_P_ATALK:
 348                 return NP_AT;
 349         case ETH_P_MPLS_UC:
 350                 return NP_MPLS_UC;
 351         case ETH_P_MPLS_MC:
 352                 return NP_MPLS_MC;
 353         }
 354         return -1;
 355 }
 356
 357 /* Translates an NP index into an ethertype */
 358 static const int npindex_to_ethertype[NUM_NP] = {
 359         ETH_P_IP,
 360         ETH_P_IPV6,
 361         ETH_P_IPX,
 362         ETH_P_PPPTALK,
 363         ETH_P_MPLS_UC,
 364         ETH_P_MPLS_MC,
 365 };
 366
 367 /*
 368  * Locking shorthand.
 369  */
 370 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 371 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 372 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 373 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 374 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 375                                      ppp_recv_lock(ppp); } while (0)
 376 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 377                                      ppp_xmit_unlock(ppp); } while (0)
 378
 379 /*
 380  * /dev/ppp device routines.
 381  * The /dev/ppp device is used by pppd to control the ppp unit.
 382  * It supports the read, write, ioctl and poll functions.
 383  * Open instances of /dev/ppp can be in one of three states:
 384  * unattached, attached to a ppp unit, or attached to a ppp channel.
 385  */
 386 static int ppp_open(struct inode *inode, struct file *file)
 387 {
 388         /*
 389          * This could (should?) be enforced by the permissions on /dev/ppp.
 390          */
 391         if (!capable(CAP_NET_ADMIN))
 392                 return -EPERM;
 393         return 0;
 394 }
 395
 396 static int ppp_release(struct inode *unused, struct file *file)
 397 {
 398         struct ppp_file *pf = file->private_data;
 399         struct ppp *ppp;
 400
 401         if (pf) {
 402                 file->private_data = NULL;
 403                 if (pf->kind == INTERFACE) {
 404                         ppp = PF_TO_PPP(pf);
 405                         rtnl_lock();
 406                         if (file == ppp->owner)
 407                                 unregister_netdevice(ppp->dev);
 408                         rtnl_unlock();
 409                 }
 410                 if (atomic_dec_and_test(&pf->refcnt)) {
 411                         switch (pf->kind) {
 412                         case INTERFACE:
 413                                 ppp_destroy_interface(PF_TO_PPP(pf));
 414                                 break;
 415                         case CHANNEL:
 416                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 417                                 break;
 418                         }
 419                 }
 420         }
 421         return 0;
 422 }
 423
 424 static ssize_t ppp_read(struct file *file, char __user *buf,
 425                         size_t count, loff_t *ppos)
 426 {
 427         struct ppp_file *pf = file->private_data;
 428         DECLARE_WAITQUEUE(wait, current);
 429         ssize_t ret;
 430         struct sk_buff *skb = NULL;
 431         struct iovec iov;
 432         struct iov_iter to;
 433
 434         ret = count;
 435
 436         if (!pf)
 437                 return -ENXIO;
 438         add_wait_queue(&pf->rwait, &wait);
 439         for (;;) {
 440                 set_current_state(TASK_INTERRUPTIBLE);
 441                 skb = skb_dequeue(&pf->rq);
 442                 if (skb)
 443                         break;
 444                 ret = 0;
 445                 if (pf->dead)
 446                         break;
 447                 if (pf->kind == INTERFACE) {
 448                         /*
 449                          * Return 0 (EOF) on an interface that has no
 450                          * channels connected, unless it is looping
 451                          * network traffic (demand mode).
 452                          */
 453                         struct ppp *ppp = PF_TO_PPP(pf);
 454
 455                         ppp_recv_lock(ppp);
 456                         if (ppp->n_channels == 0 &&
 457                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 458                                 ppp_recv_unlock(ppp);
 459                                 break;
 460                         }
 461                         ppp_recv_unlock(ppp);
 462                 }
 463                 ret = -EAGAIN;
 464                 if (file->f_flags & O_NONBLOCK)
 465                         break;
 466                 ret = -ERESTARTSYS;
 467                 if (signal_pending(current))
 468                         break;
 469                 schedule();
 470         }
 471         set_current_state(TASK_RUNNING);
 472         remove_wait_queue(&pf->rwait, &wait);
 473
 474         if (!skb)
 475                 goto out;
 476
 477         ret = -EOVERFLOW;
 478         if (skb->len > count)
 479                 goto outf;
 480         ret = -EFAULT;
 481         iov.iov_base = buf;
 482         iov.iov_len = count;
 483         iov_iter_init(&to, READ, &iov, 1, count);
 484         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 485                 goto outf;
 486         ret = skb->len;
 487
 488  outf:
 489         kfree_skb(skb);
 490  out:
 491         return ret;
 492 }
 493
 494 static ssize_t ppp_write(struct file *file, const char __user *buf,
 495                          size_t count, loff_t *ppos)
 496 {
 497         struct ppp_file *pf = file->private_data;
 498         struct sk_buff *skb;
 499         ssize_t ret;
 500
 501         if (!pf)
 502                 return -ENXIO;
 503         ret = -ENOMEM;
 504         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 505         if (!skb)
 506                 goto out;
 507         skb_reserve(skb, pf->hdrlen);
 508         ret = -EFAULT;
 509         if (copy_from_user(skb_put(skb, count), buf, count)) {
 510                 kfree_skb(skb);
 511                 goto out;
 512         }
 513
 514         switch (pf->kind) {
 515         case INTERFACE:
 516                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 517                 break;
 518         case CHANNEL:
 519                 skb_queue_tail(&pf->xq, skb);
 520                 ppp_channel_push(PF_TO_CHANNEL(pf));
 521                 break;
 522         }
 523
 524         ret = count;
 525
 526  out:
 527         return ret;
 528 }
 529
 530 /* No kernel lock - fine */
 531 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 532 {
 533         struct ppp_file *pf = file->private_data;
 534         unsigned int mask;
 535
 536         if (!pf)
 537                 return 0;
 538         poll_wait(file, &pf->rwait, wait);
 539         mask = POLLOUT | POLLWRNORM;
 540         if (skb_peek(&pf->rq))
 541                 mask |= POLLIN | POLLRDNORM;
 542         if (pf->dead)
 543                 mask |= POLLHUP;
 544         else if (pf->kind == INTERFACE) {
 545                 /* see comment in ppp_read */
 546                 struct ppp *ppp = PF_TO_PPP(pf);
 547
 548                 ppp_recv_lock(ppp);
 549                 if (ppp->n_channels == 0 &&
 550                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 551                         mask |= POLLIN | POLLRDNORM;
 552                 ppp_recv_unlock(ppp);
 553         }
 554
 555         return mask;
 556 }
 557
 558 #ifdef CONFIG_PPP_FILTER
 559 static int get_filter(void __user *arg, struct sock_filter **p)
 560 {
 561         struct sock_fprog uprog;
 562         struct sock_filter *code = NULL;
 563         int len;
 564
 565         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 566                 return -EFAULT;
 567
 568         if (!uprog.len) {
 569                 *p = NULL;
 570                 return 0;
 571         }
 572
 573         len = uprog.len * sizeof(struct sock_filter);
 574         code = memdup_user(uprog.filter, len);
 575         if (IS_ERR(code))
 576                 return PTR_ERR(code);
 577
 578         *p = code;
 579         return uprog.len;
 580 }
 581 #endif /* CONFIG_PPP_FILTER */
 582
 583 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 584 {
 585         struct ppp_file *pf;
 586         struct ppp *ppp;
 587         int err = -EFAULT, val, val2, i;
 588         struct ppp_idle idle;
 589         struct npioctl npi;
 590         int unit, cflags;
 591         struct slcompress *vj;
 592         void __user *argp = (void __user *)arg;
 593         int __user *p = argp;
 594
 595         mutex_lock(&ppp_mutex);
 596
 597         pf = file->private_data;
 598         if (!pf) {
 599                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 600                                            pf, file, cmd, arg);
 601                 goto out;
 602         }
 603
 604         if (cmd == PPPIOCDETACH) {
 605                 /*
 606                  * We have to be careful here... if the file descriptor
 607                  * has been dup'd, we could have another process in the
 608                  * middle of a poll using the same file *, so we had
 609                  * better not free the interface data structures -
 610                  * instead we fail the ioctl.  Even in this case, we
 611                  * shut down the interface if we are the owner of it.
 612                  * Actually, we should get rid of PPPIOCDETACH, userland
 613                  * (i.e. pppd) could achieve the same effect by closing
 614                  * this fd and reopening /dev/ppp.
 615                  */
 616                 err = -EINVAL;
 617                 if (pf->kind == INTERFACE) {
 618                         ppp = PF_TO_PPP(pf);
 619                         rtnl_lock();
 620                         if (file == ppp->owner)
 621                                 unregister_netdevice(ppp->dev);
 622                         rtnl_unlock();
 623                 }
 624                 if (atomic_long_read(&file->f_count) < 2) {
 625                         ppp_release(NULL, file);
 626                         err = 0;
 627                 } else
 628                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 629                                 atomic_long_read(&file->f_count));
 630                 goto out;
 631         }
 632
 633         if (pf->kind == CHANNEL) {
 634                 struct channel *pch;
 635                 struct ppp_channel *chan;
 636
 637                 pch = PF_TO_CHANNEL(pf);
 638
 639                 switch (cmd) {
 640                 case PPPIOCCONNECT:
 641                         if (get_user(unit, p))
 642                                 break;
 643                         err = ppp_connect_channel(pch, unit);
 644                         break;
 645
 646                 case PPPIOCDISCONN:
 647                         err = ppp_disconnect_channel(pch);
 648                         break;
 649
 650                 default:
 651                         down_read(&pch->chan_sem);
 652                         chan = pch->chan;
 653                         err = -ENOTTY;
 654                         if (chan && chan->ops->ioctl)
 655                                 err = chan->ops->ioctl(chan, cmd, arg);
 656                         up_read(&pch->chan_sem);
 657                 }
 658                 goto out;
 659         }
 660
 661         if (pf->kind != INTERFACE) {
 662                 /* can't happen */
 663                 pr_err("PPP: not interface or channel??\n");
 664                 err = -EINVAL;
 665                 goto out;
 666         }
 667
 668         ppp = PF_TO_PPP(pf);
 669         switch (cmd) {
 670         case PPPIOCSMRU:
 671                 if (get_user(val, p))
 672                         break;
 673                 ppp->mru = val;
 674                 err = 0;
 675                 break;
 676
 677         case PPPIOCSFLAGS:
 678                 if (get_user(val, p))
 679                         break;
 680                 ppp_lock(ppp);
 681                 cflags = ppp->flags & ~val;
 682 #ifdef CONFIG_PPP_MULTILINK
 683                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 684                         ppp->nextseq = 0;
 685 #endif
 686                 ppp->flags = val & SC_FLAG_BITS;
 687                 ppp_unlock(ppp);
 688                 if (cflags & SC_CCP_OPEN)
 689                         ppp_ccp_closed(ppp);
 690                 err = 0;
 691                 break;
 692
 693         case PPPIOCGFLAGS:
 694                 val = ppp->flags | ppp->xstate | ppp->rstate;
 695                 if (put_user(val, p))
 696                         break;
 697                 err = 0;
 698                 break;
 699
 700         case PPPIOCSCOMPRESS:
 701                 err = ppp_set_compress(ppp, arg);
 702                 break;
 703
 704         case PPPIOCGUNIT:
 705                 if (put_user(ppp->file.index, p))
 706                         break;
 707                 err = 0;
 708                 break;
 709
 710         case PPPIOCSDEBUG:
 711                 if (get_user(val, p))
 712                         break;
 713                 ppp->debug = val;
 714                 err = 0;
 715                 break;
 716
 717         case PPPIOCGDEBUG:
 718                 if (put_user(ppp->debug, p))
 719                         break;
 720                 err = 0;
 721                 break;
 722
 723         case PPPIOCGIDLE:
 724                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 725                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 726                 if (copy_to_user(argp, &idle, sizeof(idle)))
 727                         break;
 728                 err = 0;
 729                 break;
 730
 731         case PPPIOCSMAXCID:
 732                 if (get_user(val, p))
 733                         break;
 734                 val2 = 15;
 735                 if ((val >> 16) != 0) {
 736                         val2 = val >> 16;
 737                         val &= 0xffff;
 738                 }
 739                 vj = slhc_init(val2+1, val+1);
 740                 if (IS_ERR(vj)) {
 741                         err = PTR_ERR(vj);
 742                         break;
 743                 }
 744                 ppp_lock(ppp);
 745                 if (ppp->vj)
 746                         slhc_free(ppp->vj);
 747                 ppp->vj = vj;
 748                 ppp_unlock(ppp);
 749                 err = 0;
 750                 break;
 751
 752         case PPPIOCGNPMODE:
 753         case PPPIOCSNPMODE:
 754                 if (copy_from_user(&npi, argp, sizeof(npi)))
 755                         break;
 756                 err = proto_to_npindex(npi.protocol);
 757                 if (err < 0)
 758                         break;
 759                 i = err;
 760                 if (cmd == PPPIOCGNPMODE) {
 761                         err = -EFAULT;
 762                         npi.mode = ppp->npmode[i];
 763                         if (copy_to_user(argp, &npi, sizeof(npi)))
 764                                 break;
 765                 } else {
 766                         ppp->npmode[i] = npi.mode;
 767                         /* we may be able to transmit more packets now (??) */
 768                         netif_wake_queue(ppp->dev);
 769                 }
 770                 err = 0;
 771                 break;
 772
 773 #ifdef CONFIG_PPP_FILTER
 774         case PPPIOCSPASS:
 775         {
 776                 struct sock_filter *code;
 777
 778                 err = get_filter(argp, &code);
 779                 if (err >= 0) {
 780                         struct bpf_prog *pass_filter = NULL;
 781                         struct sock_fprog_kern fprog = {
 782                                 .len = err,
 783                                 .filter = code,
 784                         };
 785
 786                         err = 0;
 787                         if (fprog.filter)
 788                                 err = bpf_prog_create(&pass_filter, &fprog);
 789                         if (!err) {
 790                                 ppp_lock(ppp);
 791                                 if (ppp->pass_filter)
 792                                         bpf_prog_destroy(ppp->pass_filter);
 793                                 ppp->pass_filter = pass_filter;
 794                                 ppp_unlock(ppp);
 795                         }
 796                         kfree(code);
 797                 }
 798                 break;
 799         }
 800         case PPPIOCSACTIVE:
 801         {
 802                 struct sock_filter *code;
 803
 804                 err = get_filter(argp, &code);
 805                 if (err >= 0) {
 806                         struct bpf_prog *active_filter = NULL;
 807                         struct sock_fprog_kern fprog = {
 808                                 .len = err,
 809                                 .filter = code,
 810                         };
 811
 812                         err = 0;
 813                         if (fprog.filter)
 814                                 err = bpf_prog_create(&active_filter, &fprog);
 815                         if (!err) {
 816                                 ppp_lock(ppp);
 817                                 if (ppp->active_filter)
 818                                         bpf_prog_destroy(ppp->active_filter);
 819                                 ppp->active_filter = active_filter;
 820                                 ppp_unlock(ppp);
 821                         }
 822                         kfree(code);
 823                 }
 824                 break;
 825         }
 826 #endif /* CONFIG_PPP_FILTER */
 827
 828 #ifdef CONFIG_PPP_MULTILINK
 829         case PPPIOCSMRRU:
 830                 if (get_user(val, p))
 831                         break;
 832                 ppp_recv_lock(ppp);
 833                 ppp->mrru = val;
 834                 ppp_recv_unlock(ppp);
 835                 err = 0;
 836                 break;
 837 #endif /* CONFIG_PPP_MULTILINK */
 838
 839         default:
 840                 err = -ENOTTY;
 841         }
 842
 843 out:
 844         mutex_unlock(&ppp_mutex);
 845
 846         return err;
 847 }
 848
 849 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 850                         struct file *file, unsigned int cmd, unsigned long arg)
 851 {
 852         int unit, err = -EFAULT;
 853         struct ppp *ppp;
 854         struct channel *chan;
 855         struct ppp_net *pn;
 856         int __user *p = (int __user *)arg;
 857
 858         switch (cmd) {
 859         case PPPIOCNEWUNIT:
 860                 /* Create a new ppp unit */
 861                 if (get_user(unit, p))
 862                         break;
 863                 err = ppp_create_interface(net, file, &unit);
 864                 if (err < 0)
 865                         break;
 866
 867                 err = -EFAULT;
 868                 if (put_user(unit, p))
 869                         break;
 870                 err = 0;
 871                 break;
 872
 873         case PPPIOCATTACH:
 874                 /* Attach to an existing ppp unit */
 875                 if (get_user(unit, p))
 876                         break;
 877                 err = -ENXIO;
 878                 pn = ppp_pernet(net);
 879                 mutex_lock(&pn->all_ppp_mutex);
 880                 ppp = ppp_find_unit(pn, unit);
 881                 if (ppp) {
 882                         atomic_inc(&ppp->file.refcnt);
 883                         file->private_data = &ppp->file;
 884                         err = 0;
 885                 }
 886                 mutex_unlock(&pn->all_ppp_mutex);
 887                 break;
 888
 889         case PPPIOCATTCHAN:
 890                 if (get_user(unit, p))
 891                         break;
 892                 err = -ENXIO;
 893                 pn = ppp_pernet(net);
 894                 spin_lock_bh(&pn->all_channels_lock);
 895                 chan = ppp_find_channel(pn, unit);
 896                 if (chan) {
 897                         atomic_inc(&chan->file.refcnt);
 898                         file->private_data = &chan->file;
 899                         err = 0;
 900                 }
 901                 spin_unlock_bh(&pn->all_channels_lock);
 902                 break;
 903
 904         default:
 905                 err = -ENOTTY;
 906         }
 907
 908         return err;
 909 }
 910
 911 static const struct file_operations ppp_device_fops = {
 912         .owner          = THIS_MODULE,
 913         .read           = ppp_read,
 914         .write          = ppp_write,
 915         .poll           = ppp_poll,
 916         .unlocked_ioctl = ppp_ioctl,
 917         .open           = ppp_open,
 918         .release        = ppp_release,
 919         .llseek         = noop_llseek,
 920 };
 921
 922 static __net_init int ppp_init_net(struct net *net)
 923 {
 924         struct ppp_net *pn = net_generic(net, ppp_net_id);
 925
 926         idr_init(&pn->units_idr);
 927         mutex_init(&pn->all_ppp_mutex);
 928
 929         INIT_LIST_HEAD(&pn->all_channels);
 930         INIT_LIST_HEAD(&pn->new_channels);
 931
 932         spin_lock_init(&pn->all_channels_lock);
 933
 934         return 0;
 935 }
 936
 937 static __net_exit void ppp_exit_net(struct net *net)
 938 {
 939         struct ppp_net *pn = net_generic(net, ppp_net_id);
 940         struct net_device *dev;
 941         struct net_device *aux;
 942         struct ppp *ppp;
 943         LIST_HEAD(list);
 944         int id;
 945
 946         rtnl_lock();
 947         for_each_netdev_safe(net, dev, aux) {
 948                 if (dev->netdev_ops == &ppp_netdev_ops)
 949                         unregister_netdevice_queue(dev, &list);
 950         }
 951
 952         idr_for_each_entry(&pn->units_idr, ppp, id)
 953                 /* Skip devices already unregistered by previous loop */
 954                 if (!net_eq(dev_net(ppp->dev), net))
 955                         unregister_netdevice_queue(ppp->dev, &list);
 956
 957         unregister_netdevice_many(&list);
 958         rtnl_unlock();
 959
 960         mutex_destroy(&pn->all_ppp_mutex);
 961         idr_destroy(&pn->units_idr);
 962 }
 963
 964 static struct pernet_operations ppp_net_ops = {
 965         .init = ppp_init_net,
 966         .exit = ppp_exit_net,
 967         .id   = &ppp_net_id,
 968         .size = sizeof(struct ppp_net),
 969 };
 970
 971 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
 972 {
 973         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
 974         int ret;
 975
 976         mutex_lock(&pn->all_ppp_mutex);
 977
 978         if (unit < 0) {
 979                 ret = unit_get(&pn->units_idr, ppp, 0);
 980                 if (ret < 0)
 981                         goto err;
 982                 if (!ifname_is_set) {
 983                         while (1) {
 984                                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
 985                                 if (!__dev_get_by_name(ppp->ppp_net, ppp->dev->name))
 986                                         break;
 987                                 unit_put(&pn->units_idr, ret);
 988                                 ret = unit_get(&pn->units_idr, ppp, ret + 1);
 989                                 if (ret < 0)
 990                                         goto err;
 991                         }
 992                 }
 993         } else {
 994                 /* Caller asked for a specific unit number. Fail with -EEXIST
 995                  * if unavailable. For backward compatibility, return -EEXIST
 996                  * too if idr allocation fails; this makes pppd retry without
 997                  * requesting a specific unit number.
 998                  */
 999                 if (unit_find(&pn->units_idr, unit)) {
1000                         ret = -EEXIST;
1001                         goto err;
1002                 }
1003                 ret = unit_set(&pn->units_idr, ppp, unit);
1004                 if (ret < 0) {
1005                         /* Rewrite error for backward compatibility */
1006                         ret = -EEXIST;
1007                         goto err;
1008                 }
1009         }
1010         ppp->file.index = ret;
1011
1012         if (!ifname_is_set)
1013                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1014
1015         mutex_unlock(&pn->all_ppp_mutex);
1016
1017         ret = register_netdevice(ppp->dev);
1018         if (ret < 0)
1019                 goto err_unit;
1020
1021         atomic_inc(&ppp_unit_count);
1022
1023         return 0;
1024
1025 err_unit:
1026         mutex_lock(&pn->all_ppp_mutex);
1027         unit_put(&pn->units_idr, ppp->file.index);
1028 err:
1029         mutex_unlock(&pn->all_ppp_mutex);
1030
1031         return ret;
1032 }
1033
1034 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1035                              const struct ppp_config *conf)
1036 {
1037         struct ppp *ppp = netdev_priv(dev);
1038         int indx;
1039         int err;
1040         int cpu;
1041
1042         ppp->dev = dev;
1043         ppp->ppp_net = src_net;
1044         ppp->mru = PPP_MRU;
1045         ppp->owner = conf->file;
1046
1047         init_ppp_file(&ppp->file, INTERFACE);
1048         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1049
1050         for (indx = 0; indx < NUM_NP; ++indx)
1051                 ppp->npmode[indx] = NPMODE_PASS;
1052         INIT_LIST_HEAD(&ppp->channels);
1053         spin_lock_init(&ppp->rlock);
1054         spin_lock_init(&ppp->wlock);
1055
1056         ppp->xmit_recursion = alloc_percpu(int);
1057         if (!ppp->xmit_recursion) {
1058                 err = -ENOMEM;
1059                 goto err1;
1060         }
1061         for_each_possible_cpu(cpu)
1062                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1063
1064 #ifdef CONFIG_PPP_MULTILINK
1065         ppp->minseq = -1;
1066         skb_queue_head_init(&ppp->mrq);
1067 #endif /* CONFIG_PPP_MULTILINK */
1068 #ifdef CONFIG_PPP_FILTER
1069         ppp->pass_filter = NULL;
1070         ppp->active_filter = NULL;
1071 #endif /* CONFIG_PPP_FILTER */
1072
1073         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1074         if (err < 0)
1075                 goto err2;
1076
1077         conf->file->private_data = &ppp->file;
1078
1079         return 0;
1080 err2:
1081         free_percpu(ppp->xmit_recursion);
1082 err1:
1083         return err;
1084 }
1085
1086 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1087         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1088 };
1089
1090 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[])
1091 {
1092         if (!data)
1093                 return -EINVAL;
1094
1095         if (!data[IFLA_PPP_DEV_FD])
1096                 return -EINVAL;
1097         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1098                 return -EBADF;
1099
1100         return 0;
1101 }
1102
1103 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1104                           struct nlattr *tb[], struct nlattr *data[])
1105 {
1106         struct ppp_config conf = {
1107                 .unit = -1,
1108                 .ifname_is_set = true,
1109         };
1110         struct file *file;
1111         int err;
1112
1113         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1114         if (!file)
1115                 return -EBADF;
1116
1117         /* rtnl_lock is already held here, but ppp_create_interface() locks
1118          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1119          * possible deadlock due to lock order inversion, at the cost of
1120          * pushing the problem back to userspace.
1121          */
1122         if (!mutex_trylock(&ppp_mutex)) {
1123                 err = -EBUSY;
1124                 goto out;
1125         }
1126
1127         if (file->f_op != &ppp_device_fops || file->private_data) {
1128                 err = -EBADF;
1129                 goto out_unlock;
1130         }
1131
1132         conf.file = file;
1133
1134         /* Don't use device name generated by the rtnetlink layer when ifname
1135          * isn't specified. Let ppp_dev_configure() set the device name using
1136          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1137          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1138          */
1139         if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1140                 conf.ifname_is_set = false;
1141
1142         err = ppp_dev_configure(src_net, dev, &conf);
1143
1144 out_unlock:
1145         mutex_unlock(&ppp_mutex);
1146 out:
1147         fput(file);
1148
1149         return err;
1150 }
1151
1152 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1153 {
1154         unregister_netdevice_queue(dev, head);
1155 }
1156
1157 static size_t ppp_nl_get_size(const struct net_device *dev)
1158 {
1159         return 0;
1160 }
1161
1162 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1163 {
1164         return 0;
1165 }
1166
1167 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1168 {
1169         struct ppp *ppp = netdev_priv(dev);
1170
1171         return ppp->ppp_net;
1172 }
1173
1174 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1175         .kind           = "ppp",
1176         .maxtype        = IFLA_PPP_MAX,
1177         .policy         = ppp_nl_policy,
1178         .priv_size      = sizeof(struct ppp),
1179         .setup          = ppp_setup,
1180         .validate       = ppp_nl_validate,
1181         .newlink        = ppp_nl_newlink,
1182         .dellink        = ppp_nl_dellink,
1183         .get_size       = ppp_nl_get_size,
1184         .fill_info      = ppp_nl_fill_info,
1185         .get_link_net   = ppp_nl_get_link_net,
1186 };
1187
1188 #define PPP_MAJOR       108
1189
1190 /* Called at boot time if ppp is compiled into the kernel,
1191    or at module load time (from init_module) if compiled as a module. */
1192 static int __init ppp_init(void)
1193 {
1194         int err;
1195
1196         pr_info("PPP generic driver version " PPP_VERSION "\n");
1197
1198         err = register_pernet_device(&ppp_net_ops);
1199         if (err) {
1200                 pr_err("failed to register PPP pernet device (%d)\n", err);
1201                 goto out;
1202         }
1203
1204         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1205         if (err) {
1206                 pr_err("failed to register PPP device (%d)\n", err);
1207                 goto out_net;
1208         }
1209
1210         ppp_class = class_create(THIS_MODULE, "ppp");
1211         if (IS_ERR(ppp_class)) {
1212                 err = PTR_ERR(ppp_class);
1213                 goto out_chrdev;
1214         }
1215
1216         err = rtnl_link_register(&ppp_link_ops);
1217         if (err) {
1218                 pr_err("failed to register rtnetlink PPP handler\n");
1219                 goto out_class;
1220         }
1221
1222         /* not a big deal if we fail here :-) */
1223         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1224
1225         return 0;
1226
1227 out_class:
1228         class_destroy(ppp_class);
1229 out_chrdev:
1230         unregister_chrdev(PPP_MAJOR, "ppp");
1231 out_net:
1232         unregister_pernet_device(&ppp_net_ops);
1233 out:
1234         return err;
1235 }
1236
1237 /*
1238  * Network interface unit routines.
1239  */
1240 static netdev_tx_t
1241 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1242 {
1243         struct ppp *ppp = netdev_priv(dev);
1244         int npi, proto;
1245         unsigned char *pp;
1246
1247         npi = ethertype_to_npindex(ntohs(skb->protocol));
1248         if (npi < 0)
1249                 goto outf;
1250
1251         /* Drop, accept or reject the packet */
1252         switch (ppp->npmode[npi]) {
1253         case NPMODE_PASS:
1254                 break;
1255         case NPMODE_QUEUE:
1256                 /* it would be nice to have a way to tell the network
1257                    system to queue this one up for later. */
1258                 goto outf;
1259         case NPMODE_DROP:
1260         case NPMODE_ERROR:
1261                 goto outf;
1262         }
1263
1264         /* Put the 2-byte PPP protocol number on the front,
1265            making sure there is room for the address and control fields. */
1266         if (skb_cow_head(skb, PPP_HDRLEN))
1267                 goto outf;
1268
1269         pp = skb_push(skb, 2);
1270         proto = npindex_to_proto[npi];
1271         put_unaligned_be16(proto, pp);
1272
1273         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1274         ppp_xmit_process(ppp, skb);
1275
1276         return NETDEV_TX_OK;
1277
1278  outf:
1279         kfree_skb(skb);
1280         ++dev->stats.tx_dropped;
1281         return NETDEV_TX_OK;
1282 }
1283
1284 static int
1285 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1286 {
1287         struct ppp *ppp = netdev_priv(dev);
1288         int err = -EFAULT;
1289         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1290         struct ppp_stats stats;
1291         struct ppp_comp_stats cstats;
1292         char *vers;
1293
1294         switch (cmd) {
1295         case SIOCGPPPSTATS:
1296                 ppp_get_stats(ppp, &stats);
1297                 if (copy_to_user(addr, &stats, sizeof(stats)))
1298                         break;
1299                 err = 0;
1300                 break;
1301
1302         case SIOCGPPPCSTATS:
1303                 memset(&cstats, 0, sizeof(cstats));
1304                 if (ppp->xc_state)
1305                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1306                 if (ppp->rc_state)
1307                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1308                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1309                         break;
1310                 err = 0;
1311                 break;
1312
1313         case SIOCGPPPVER:
1314                 vers = PPP_VERSION;
1315                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1316                         break;
1317                 err = 0;
1318                 break;
1319
1320         default:
1321                 err = -EINVAL;
1322         }
1323
1324         return err;
1325 }
1326
1327 static struct rtnl_link_stats64*
1328 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1329 {
1330         struct ppp *ppp = netdev_priv(dev);
1331
1332         ppp_recv_lock(ppp);
1333         stats64->rx_packets = ppp->stats64.rx_packets;
1334         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1335         ppp_recv_unlock(ppp);
1336
1337         ppp_xmit_lock(ppp);
1338         stats64->tx_packets = ppp->stats64.tx_packets;
1339         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1340         ppp_xmit_unlock(ppp);
1341
1342         stats64->rx_errors        = dev->stats.rx_errors;
1343         stats64->tx_errors        = dev->stats.tx_errors;
1344         stats64->rx_dropped       = dev->stats.rx_dropped;
1345         stats64->tx_dropped       = dev->stats.tx_dropped;
1346         stats64->rx_length_errors = dev->stats.rx_length_errors;
1347
1348         return stats64;
1349 }
1350
1351 static int ppp_dev_init(struct net_device *dev)
1352 {
1353         struct ppp *ppp;
1354
1355         netdev_lockdep_set_classes(dev);
1356
1357         ppp = netdev_priv(dev);
1358         /* Let the netdevice take a reference on the ppp file. This ensures
1359          * that ppp_destroy_interface() won't run before the device gets
1360          * unregistered.
1361          */
1362         atomic_inc(&ppp->file.refcnt);
1363
1364         return 0;
1365 }
1366
1367 static void ppp_dev_uninit(struct net_device *dev)
1368 {
1369         struct ppp *ppp = netdev_priv(dev);
1370         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1371
1372         ppp_lock(ppp);
1373         ppp->closing = 1;
1374         ppp_unlock(ppp);
1375
1376         mutex_lock(&pn->all_ppp_mutex);
1377         unit_put(&pn->units_idr, ppp->file.index);
1378         mutex_unlock(&pn->all_ppp_mutex);
1379
1380         ppp->owner = NULL;
1381
1382         ppp->file.dead = 1;
1383         wake_up_interruptible(&ppp->file.rwait);
1384 }
1385
1386 static void ppp_dev_priv_destructor(struct net_device *dev)
1387 {
1388         struct ppp *ppp;
1389
1390         ppp = netdev_priv(dev);
1391         if (atomic_dec_and_test(&ppp->file.refcnt))
1392                 ppp_destroy_interface(ppp);
1393 }
1394
1395 static const struct net_device_ops ppp_netdev_ops = {
1396         .ndo_init        = ppp_dev_init,
1397         .ndo_uninit      = ppp_dev_uninit,
1398         .ndo_start_xmit  = ppp_start_xmit,
1399         .ndo_do_ioctl    = ppp_net_ioctl,
1400         .ndo_get_stats64 = ppp_get_stats64,
1401 };
1402
1403 static struct device_type ppp_type = {
1404         .name = "ppp",
1405 };
1406
1407 static void ppp_setup(struct net_device *dev)
1408 {
1409         dev->netdev_ops = &ppp_netdev_ops;
1410         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1411
1412         dev->features |= NETIF_F_LLTX;
1413
1414         dev->hard_header_len = PPP_HDRLEN;
1415         dev->mtu = PPP_MRU;
1416         dev->addr_len = 0;
1417         dev->tx_queue_len = 3;
1418         dev->type = ARPHRD_PPP;
1419         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1420         dev->destructor = ppp_dev_priv_destructor;
1421         netif_keep_dst(dev);
1422 }
1423
1424 /*
1425  * Transmit-side routines.
1426  */
1427
1428 /* Called to do any work queued up on the transmit side that can now be done */
1429 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1430 {
1431         ppp_xmit_lock(ppp);
1432         if (!ppp->closing) {
1433                 ppp_push(ppp);
1434
1435                 if (skb)
1436                         skb_queue_tail(&ppp->file.xq, skb);
1437                 while (!ppp->xmit_pending &&
1438                        (skb = skb_dequeue(&ppp->file.xq)))
1439                         ppp_send_frame(ppp, skb);
1440                 /* If there's no work left to do, tell the core net
1441                    code that we can accept some more. */
1442                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1443                         netif_wake_queue(ppp->dev);
1444                 else
1445                         netif_stop_queue(ppp->dev);
1446         } else {
1447                 kfree_skb(skb);
1448         }
1449         ppp_xmit_unlock(ppp);
1450 }
1451
1452 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1453 {
1454         local_bh_disable();
1455
1456         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1457                 goto err;
1458
1459         (*this_cpu_ptr(ppp->xmit_recursion))++;
1460         __ppp_xmit_process(ppp, skb);
1461         (*this_cpu_ptr(ppp->xmit_recursion))--;
1462
1463         local_bh_enable();
1464
1465         return;
1466
1467 err:
1468         local_bh_enable();
1469
1470         kfree_skb(skb);
1471
1472         if (net_ratelimit())
1473                 netdev_err(ppp->dev, "recursion detected\n");
1474 }
1475
1476 static inline struct sk_buff *
1477 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1478 {
1479         struct sk_buff *new_skb;
1480         int len;
1481         int new_skb_size = ppp->dev->mtu +
1482                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1483         int compressor_skb_size = ppp->dev->mtu +
1484                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1485         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1486         if (!new_skb) {
1487                 if (net_ratelimit())
1488                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1489                 return NULL;
1490         }
1491         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1492                 skb_reserve(new_skb,
1493                             ppp->dev->hard_header_len - PPP_HDRLEN);
1494
1495         /* compressor still expects A/C bytes in hdr */
1496         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1497                                    new_skb->data, skb->len + 2,
1498                                    compressor_skb_size);
1499         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1500                 consume_skb(skb);
1501                 skb = new_skb;
1502                 skb_put(skb, len);
1503                 skb_pull(skb, 2);       /* pull off A/C bytes */
1504         } else if (len == 0) {
1505                 /* didn't compress, or CCP not up yet */
1506                 consume_skb(new_skb);
1507                 new_skb = skb;
1508         } else {
1509                 /*
1510                  * (len < 0)
1511                  * MPPE requires that we do not send unencrypted
1512                  * frames.  The compressor will return -1 if we
1513                  * should drop the frame.  We cannot simply test
1514                  * the compress_proto because MPPE and MPPC share
1515                  * the same number.
1516                  */
1517                 if (net_ratelimit())
1518                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1519                 kfree_skb(skb);
1520                 consume_skb(new_skb);
1521                 new_skb = NULL;
1522         }
1523         return new_skb;
1524 }
1525
1526 /*
1527  * Compress and send a frame.
1528  * The caller should have locked the xmit path,
1529  * and xmit_pending should be 0.
1530  */
1531 static void
1532 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1533 {
1534         int proto = PPP_PROTO(skb);
1535         struct sk_buff *new_skb;
1536         int len;
1537         unsigned char *cp;
1538
1539         if (proto < 0x8000) {
1540 #ifdef CONFIG_PPP_FILTER
1541                 /* check if we should pass this packet */
1542                 /* the filter instructions are constructed assuming
1543                    a four-byte PPP header on each packet */
1544                 *skb_push(skb, 2) = 1;
1545                 if (ppp->pass_filter &&
1546                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1547                         if (ppp->debug & 1)
1548                                 netdev_printk(KERN_DEBUG, ppp->dev,
1549                                               "PPP: outbound frame "
1550                                               "not passed\n");
1551                         kfree_skb(skb);
1552                         return;
1553                 }
1554                 /* if this packet passes the active filter, record the time */
1555                 if (!(ppp->active_filter &&
1556                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1557                         ppp->last_xmit = jiffies;
1558                 skb_pull(skb, 2);
1559 #else
1560                 /* for data packets, record the time */
1561                 ppp->last_xmit = jiffies;
1562 #endif /* CONFIG_PPP_FILTER */
1563         }
1564
1565         ++ppp->stats64.tx_packets;
1566         ppp->stats64.tx_bytes += skb->len - 2;
1567
1568         switch (proto) {
1569         case PPP_IP:
1570                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1571                         break;
1572                 /* try to do VJ TCP header compression */
1573                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1574                                     GFP_ATOMIC);
1575                 if (!new_skb) {
1576                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1577                         goto drop;
1578                 }
1579                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1580                 cp = skb->data + 2;
1581                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1582                                     new_skb->data + 2, &cp,
1583                                     !(ppp->flags & SC_NO_TCP_CCID));
1584                 if (cp == skb->data + 2) {
1585                         /* didn't compress */
1586                         consume_skb(new_skb);
1587                 } else {
1588                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1589                                 proto = PPP_VJC_COMP;
1590                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1591                         } else {
1592                                 proto = PPP_VJC_UNCOMP;
1593                                 cp[0] = skb->data[2];
1594                         }
1595                         consume_skb(skb);
1596                         skb = new_skb;
1597                         cp = skb_put(skb, len + 2);
1598                         cp[0] = 0;
1599                         cp[1] = proto;
1600                 }
1601                 break;
1602
1603         case PPP_CCP:
1604                 /* peek at outbound CCP frames */
1605                 ppp_ccp_peek(ppp, skb, 0);
1606                 break;
1607         }
1608
1609         /* try to do packet compression */
1610         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1611             proto != PPP_LCP && proto != PPP_CCP) {
1612                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1613                         if (net_ratelimit())
1614                                 netdev_err(ppp->dev,
1615                                            "ppp: compression required but "
1616                                            "down - pkt dropped.\n");
1617                         goto drop;
1618                 }
1619                 skb = pad_compress_skb(ppp, skb);
1620                 if (!skb)
1621                         goto drop;
1622         }
1623
1624         /*
1625          * If we are waiting for traffic (demand dialling),
1626          * queue it up for pppd to receive.
1627          */
1628         if (ppp->flags & SC_LOOP_TRAFFIC) {
1629                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1630                         goto drop;
1631                 skb_queue_tail(&ppp->file.rq, skb);
1632                 wake_up_interruptible(&ppp->file.rwait);
1633                 return;
1634         }
1635
1636         ppp->xmit_pending = skb;
1637         ppp_push(ppp);
1638         return;
1639
1640  drop:
1641         kfree_skb(skb);
1642         ++ppp->dev->stats.tx_errors;
1643 }
1644
1645 /*
1646  * Try to send the frame in xmit_pending.
1647  * The caller should have the xmit path locked.
1648  */
1649 static void
1650 ppp_push(struct ppp *ppp)
1651 {
1652         struct list_head *list;
1653         struct channel *pch;
1654         struct sk_buff *skb = ppp->xmit_pending;
1655
1656         if (!skb)
1657                 return;
1658
1659         list = &ppp->channels;
1660         if (list_empty(list)) {
1661                 /* nowhere to send the packet, just drop it */
1662                 ppp->xmit_pending = NULL;
1663                 kfree_skb(skb);
1664                 return;
1665         }
1666
1667         if ((ppp->flags & SC_MULTILINK) == 0) {
1668                 /* not doing multilink: send it down the first channel */
1669                 list = list->next;
1670                 pch = list_entry(list, struct channel, clist);
1671
1672                 spin_lock_bh(&pch->downl);
1673                 if (pch->chan) {
1674                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1675                                 ppp->xmit_pending = NULL;
1676                 } else {
1677                         /* channel got unregistered */
1678                         kfree_skb(skb);
1679                         ppp->xmit_pending = NULL;
1680                 }
1681                 spin_unlock_bh(&pch->downl);
1682                 return;
1683         }
1684
1685 #ifdef CONFIG_PPP_MULTILINK
1686         /* Multilink: fragment the packet over as many links
1687            as can take the packet at the moment. */
1688         if (!ppp_mp_explode(ppp, skb))
1689                 return;
1690 #endif /* CONFIG_PPP_MULTILINK */
1691
1692         ppp->xmit_pending = NULL;
1693         kfree_skb(skb);
1694 }
1695
1696 #ifdef CONFIG_PPP_MULTILINK
1697 static bool mp_protocol_compress __read_mostly = true;
1698 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1699 MODULE_PARM_DESC(mp_protocol_compress,
1700                  "compress protocol id in multilink fragments");
1701
1702 /*
1703  * Divide a packet to be transmitted into fragments and
1704  * send them out the individual links.
1705  */
1706 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1707 {
1708         int len, totlen;
1709         int i, bits, hdrlen, mtu;
1710         int flen;
1711         int navail, nfree, nzero;
1712         int nbigger;
1713         int totspeed;
1714         int totfree;
1715         unsigned char *p, *q;
1716         struct list_head *list;
1717         struct channel *pch;
1718         struct sk_buff *frag;
1719         struct ppp_channel *chan;
1720
1721         totspeed = 0; /*total bitrate of the bundle*/
1722         nfree = 0; /* # channels which have no packet already queued */
1723         navail = 0; /* total # of usable channels (not deregistered) */
1724         nzero = 0; /* number of channels with zero speed associated*/
1725         totfree = 0; /*total # of channels available and
1726                                   *having no queued packets before
1727                                   *starting the fragmentation*/
1728
1729         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1730         i = 0;
1731         list_for_each_entry(pch, &ppp->channels, clist) {
1732                 if (pch->chan) {
1733                         pch->avail = 1;
1734                         navail++;
1735                         pch->speed = pch->chan->speed;
1736                 } else {
1737                         pch->avail = 0;
1738                 }
1739                 if (pch->avail) {
1740                         if (skb_queue_empty(&pch->file.xq) ||
1741                                 !pch->had_frag) {
1742                                         if (pch->speed == 0)
1743                                                 nzero++;
1744                                         else
1745                                                 totspeed += pch->speed;
1746
1747                                         pch->avail = 2;
1748                                         ++nfree;
1749                                         ++totfree;
1750                                 }
1751                         if (!pch->had_frag && i < ppp->nxchan)
1752                                 ppp->nxchan = i;
1753                 }
1754                 ++i;
1755         }
1756         /*
1757          * Don't start sending this packet unless at least half of
1758          * the channels are free.  This gives much better TCP
1759          * performance if we have a lot of channels.
1760          */
1761         if (nfree == 0 || nfree < navail / 2)
1762                 return 0; /* can't take now, leave it in xmit_pending */
1763
1764         /* Do protocol field compression */
1765         p = skb->data;
1766         len = skb->len;
1767         if (*p == 0 && mp_protocol_compress) {
1768                 ++p;
1769                 --len;
1770         }
1771
1772         totlen = len;
1773         nbigger = len % nfree;
1774
1775         /* skip to the channel after the one we last used
1776            and start at that one */
1777         list = &ppp->channels;
1778         for (i = 0; i < ppp->nxchan; ++i) {
1779                 list = list->next;
1780                 if (list == &ppp->channels) {
1781                         i = 0;
1782                         break;
1783                 }
1784         }
1785
1786         /* create a fragment for each channel */
1787         bits = B;
1788         while (len > 0) {
1789                 list = list->next;
1790                 if (list == &ppp->channels) {
1791                         i = 0;
1792                         continue;
1793                 }
1794                 pch = list_entry(list, struct channel, clist);
1795                 ++i;
1796                 if (!pch->avail)
1797                         continue;
1798
1799                 /*
1800                  * Skip this channel if it has a fragment pending already and
1801                  * we haven't given a fragment to all of the free channels.
1802                  */
1803                 if (pch->avail == 1) {
1804                         if (nfree > 0)
1805                                 continue;
1806                 } else {
1807                         pch->avail = 1;
1808                 }
1809
1810                 /* check the channel's mtu and whether it is still attached. */
1811                 spin_lock_bh(&pch->downl);
1812                 if (pch->chan == NULL) {
1813                         /* can't use this channel, it's being deregistered */
1814                         if (pch->speed == 0)
1815                                 nzero--;
1816                         else
1817                                 totspeed -= pch->speed;
1818
1819                         spin_unlock_bh(&pch->downl);
1820                         pch->avail = 0;
1821                         totlen = len;
1822                         totfree--;
1823                         nfree--;
1824                         if (--navail == 0)
1825                                 break;
1826                         continue;
1827                 }
1828
1829                 /*
1830                 *if the channel speed is not set divide
1831                 *the packet evenly among the free channels;
1832                 *otherwise divide it according to the speed
1833                 *of the channel we are going to transmit on
1834                 */
1835                 flen = len;
1836                 if (nfree > 0) {
1837                         if (pch->speed == 0) {
1838                                 flen = len/nfree;
1839                                 if (nbigger > 0) {
1840                                         flen++;
1841                                         nbigger--;
1842                                 }
1843                         } else {
1844                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1845                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1846                                 if (nbigger > 0) {
1847                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1848                                         nbigger -= ((totfree - nzero)*pch->speed)/
1849                                                         totspeed;
1850                                 }
1851                         }
1852                         nfree--;
1853                 }
1854
1855                 /*
1856                  *check if we are on the last channel or
1857                  *we exceded the length of the data to
1858                  *fragment
1859                  */
1860                 if ((nfree <= 0) || (flen > len))
1861                         flen = len;
1862                 /*
1863                  *it is not worth to tx on slow channels:
1864                  *in that case from the resulting flen according to the
1865                  *above formula will be equal or less than zero.
1866                  *Skip the channel in this case
1867                  */
1868                 if (flen <= 0) {
1869                         pch->avail = 2;
1870                         spin_unlock_bh(&pch->downl);
1871                         continue;
1872                 }
1873
1874                 /*
1875                  * hdrlen includes the 2-byte PPP protocol field, but the
1876                  * MTU counts only the payload excluding the protocol field.
1877                  * (RFC1661 Section 2)
1878                  */
1879                 mtu = pch->chan->mtu - (hdrlen - 2);
1880                 if (mtu < 4)
1881                         mtu = 4;
1882                 if (flen > mtu)
1883                         flen = mtu;
1884                 if (flen == len)
1885                         bits |= E;
1886                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1887                 if (!frag)
1888                         goto noskb;
1889                 q = skb_put(frag, flen + hdrlen);
1890
1891                 /* make the MP header */
1892                 put_unaligned_be16(PPP_MP, q);
1893                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1894                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1895                         q[3] = ppp->nxseq;
1896                 } else {
1897                         q[2] = bits;
1898                         q[3] = ppp->nxseq >> 16;
1899                         q[4] = ppp->nxseq >> 8;
1900                         q[5] = ppp->nxseq;
1901                 }
1902
1903                 memcpy(q + hdrlen, p, flen);
1904
1905                 /* try to send it down the channel */
1906                 chan = pch->chan;
1907                 if (!skb_queue_empty(&pch->file.xq) ||
1908                         !chan->ops->start_xmit(chan, frag))
1909                         skb_queue_tail(&pch->file.xq, frag);
1910                 pch->had_frag = 1;
1911                 p += flen;
1912                 len -= flen;
1913                 ++ppp->nxseq;
1914                 bits = 0;
1915                 spin_unlock_bh(&pch->downl);
1916         }
1917         ppp->nxchan = i;
1918
1919         return 1;
1920
1921  noskb:
1922         spin_unlock_bh(&pch->downl);
1923         if (ppp->debug & 1)
1924                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1925         ++ppp->dev->stats.tx_errors;
1926         ++ppp->nxseq;
1927         return 1;       /* abandon the frame */
1928 }
1929 #endif /* CONFIG_PPP_MULTILINK */
1930
1931 /* Try to send data out on a channel */
1932 static void __ppp_channel_push(struct channel *pch)
1933 {
1934         struct sk_buff *skb;
1935         struct ppp *ppp;
1936
1937         spin_lock_bh(&pch->downl);
1938         if (pch->chan) {
1939                 while (!skb_queue_empty(&pch->file.xq)) {
1940                         skb = skb_dequeue(&pch->file.xq);
1941                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1942                                 /* put the packet back and try again later */
1943                                 skb_queue_head(&pch->file.xq, skb);
1944                                 break;
1945                         }
1946                 }
1947         } else {
1948                 /* channel got deregistered */
1949                 skb_queue_purge(&pch->file.xq);
1950         }
1951         spin_unlock_bh(&pch->downl);
1952         /* see if there is anything from the attached unit to be sent */
1953         if (skb_queue_empty(&pch->file.xq)) {
1954                 ppp = pch->ppp;
1955                 if (ppp)
1956                         __ppp_xmit_process(ppp, NULL);
1957         }
1958 }
1959
1960 static void ppp_channel_push(struct channel *pch)
1961 {
1962         read_lock_bh(&pch->upl);
1963         if (pch->ppp) {
1964                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
1965                 __ppp_channel_push(pch);
1966                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
1967         } else {
1968                 __ppp_channel_push(pch);
1969         }
1970         read_unlock_bh(&pch->upl);
1971 }
1972
1973 /*
1974  * Receive-side routines.
1975  */
1976
1977 struct ppp_mp_skb_parm {
1978         u32             sequence;
1979         u8              BEbits;
1980 };
1981 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1982
1983 static inline void
1984 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1985 {
1986         ppp_recv_lock(ppp);
1987         if (!ppp->closing)
1988                 ppp_receive_frame(ppp, skb, pch);
1989         else
1990                 kfree_skb(skb);
1991         ppp_recv_unlock(ppp);
1992 }
1993
1994 void
1995 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1996 {
1997         struct channel *pch = chan->ppp;
1998         int proto;
1999
2000         if (!pch) {
2001                 kfree_skb(skb);
2002                 return;
2003         }
2004
2005         read_lock_bh(&pch->upl);
2006         if (!pskb_may_pull(skb, 2)) {
2007                 kfree_skb(skb);
2008                 if (pch->ppp) {
2009                         ++pch->ppp->dev->stats.rx_length_errors;
2010                         ppp_receive_error(pch->ppp);
2011                 }
2012                 goto done;
2013         }
2014
2015         proto = PPP_PROTO(skb);
2016         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2017                 /* put it on the channel queue */
2018                 skb_queue_tail(&pch->file.rq, skb);
2019                 /* drop old frames if queue too long */
2020                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2021                        (skb = skb_dequeue(&pch->file.rq)))
2022                         kfree_skb(skb);
2023                 wake_up_interruptible(&pch->file.rwait);
2024         } else {
2025                 ppp_do_recv(pch->ppp, skb, pch);
2026         }
2027
2028 done:
2029         read_unlock_bh(&pch->upl);
2030 }
2031
2032 /* Put a 0-length skb in the receive queue as an error indication */
2033 void
2034 ppp_input_error(struct ppp_channel *chan, int code)
2035 {
2036         struct channel *pch = chan->ppp;
2037         struct sk_buff *skb;
2038
2039         if (!pch)
2040                 return;
2041
2042         read_lock_bh(&pch->upl);
2043         if (pch->ppp) {
2044                 skb = alloc_skb(0, GFP_ATOMIC);
2045                 if (skb) {
2046                         skb->len = 0;           /* probably unnecessary */
2047                         skb->cb[0] = code;
2048                         ppp_do_recv(pch->ppp, skb, pch);
2049                 }
2050         }
2051         read_unlock_bh(&pch->upl);
2052 }
2053
2054 /*
2055  * We come in here to process a received frame.
2056  * The receive side of the ppp unit is locked.
2057  */
2058 static void
2059 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2060 {
2061         /* note: a 0-length skb is used as an error indication */
2062         if (skb->len > 0) {
2063                 skb_checksum_complete_unset(skb);
2064 #ifdef CONFIG_PPP_MULTILINK
2065                 /* XXX do channel-level decompression here */
2066                 if (PPP_PROTO(skb) == PPP_MP)
2067                         ppp_receive_mp_frame(ppp, skb, pch);
2068                 else
2069 #endif /* CONFIG_PPP_MULTILINK */
2070                         ppp_receive_nonmp_frame(ppp, skb);
2071         } else {
2072                 kfree_skb(skb);
2073                 ppp_receive_error(ppp);
2074         }
2075 }
2076
2077 static void
2078 ppp_receive_error(struct ppp *ppp)
2079 {
2080         ++ppp->dev->stats.rx_errors;
2081         if (ppp->vj)
2082                 slhc_toss(ppp->vj);
2083 }
2084
2085 static void
2086 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2087 {
2088         struct sk_buff *ns;
2089         int proto, len, npi;
2090
2091         /*
2092          * Decompress the frame, if compressed.
2093          * Note that some decompressors need to see uncompressed frames
2094          * that come in as well as compressed frames.
2095          */
2096         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2097             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2098                 skb = ppp_decompress_frame(ppp, skb);
2099
2100         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2101                 goto err;
2102
2103         proto = PPP_PROTO(skb);
2104         switch (proto) {
2105         case PPP_VJC_COMP:
2106                 /* decompress VJ compressed packets */
2107                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2108                         goto err;
2109
2110                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2111                         /* copy to a new sk_buff with more tailroom */
2112                         ns = dev_alloc_skb(skb->len + 128);
2113                         if (!ns) {
2114                                 netdev_err(ppp->dev, "PPP: no memory "
2115                                            "(VJ decomp)\n");
2116                                 goto err;
2117                         }
2118                         skb_reserve(ns, 2);
2119                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2120                         consume_skb(skb);
2121                         skb = ns;
2122                 }
2123                 else
2124                         skb->ip_summed = CHECKSUM_NONE;
2125
2126                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2127                 if (len <= 0) {
2128                         netdev_printk(KERN_DEBUG, ppp->dev,
2129                                       "PPP: VJ decompression error\n");
2130                         goto err;
2131                 }
2132                 len += 2;
2133                 if (len > skb->len)
2134                         skb_put(skb, len - skb->len);
2135                 else if (len < skb->len)
2136                         skb_trim(skb, len);
2137                 proto = PPP_IP;
2138                 break;
2139
2140         case PPP_VJC_UNCOMP:
2141                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2142                         goto err;
2143
2144                 /* Until we fix the decompressor need to make sure
2145                  * data portion is linear.
2146                  */
2147                 if (!pskb_may_pull(skb, skb->len))
2148                         goto err;
2149
2150                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2151                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2152                         goto err;
2153                 }
2154                 proto = PPP_IP;
2155                 break;
2156
2157         case PPP_CCP:
2158                 ppp_ccp_peek(ppp, skb, 1);
2159                 break;
2160         }
2161
2162         ++ppp->stats64.rx_packets;
2163         ppp->stats64.rx_bytes += skb->len - 2;
2164
2165         npi = proto_to_npindex(proto);
2166         if (npi < 0) {
2167                 /* control or unknown frame - pass it to pppd */
2168                 skb_queue_tail(&ppp->file.rq, skb);
2169                 /* limit queue length by dropping old frames */
2170                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2171                        (skb = skb_dequeue(&ppp->file.rq)))
2172                         kfree_skb(skb);
2173                 /* wake up any process polling or blocking on read */
2174                 wake_up_interruptible(&ppp->file.rwait);
2175
2176         } else {
2177                 /* network protocol frame - give it to the kernel */
2178
2179 #ifdef CONFIG_PPP_FILTER
2180                 /* check if the packet passes the pass and active filters */
2181                 /* the filter instructions are constructed assuming
2182                    a four-byte PPP header on each packet */
2183                 if (ppp->pass_filter || ppp->active_filter) {
2184                         if (skb_unclone(skb, GFP_ATOMIC))
2185                                 goto err;
2186
2187                         *skb_push(skb, 2) = 0;
2188                         if (ppp->pass_filter &&
2189                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2190                                 if (ppp->debug & 1)
2191                                         netdev_printk(KERN_DEBUG, ppp->dev,
2192                                                       "PPP: inbound frame "
2193                                                       "not passed\n");
2194                                 kfree_skb(skb);
2195                                 return;
2196                         }
2197                         if (!(ppp->active_filter &&
2198                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2199                                 ppp->last_recv = jiffies;
2200                         __skb_pull(skb, 2);
2201                 } else
2202 #endif /* CONFIG_PPP_FILTER */
2203                         ppp->last_recv = jiffies;
2204
2205                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2206                     ppp->npmode[npi] != NPMODE_PASS) {
2207                         kfree_skb(skb);
2208                 } else {
2209                         /* chop off protocol */
2210                         skb_pull_rcsum(skb, 2);
2211                         skb->dev = ppp->dev;
2212                         skb->protocol = htons(npindex_to_ethertype[npi]);
2213                         skb_reset_mac_header(skb);
2214                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2215                                                       dev_net(ppp->dev)));
2216                         netif_rx(skb);
2217                 }
2218         }
2219         return;
2220
2221  err:
2222         kfree_skb(skb);
2223         ppp_receive_error(ppp);
2224 }
2225
2226 static struct sk_buff *
2227 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2228 {
2229         int proto = PPP_PROTO(skb);
2230         struct sk_buff *ns;
2231         int len;
2232
2233         /* Until we fix all the decompressor's need to make sure
2234          * data portion is linear.
2235          */
2236         if (!pskb_may_pull(skb, skb->len))
2237                 goto err;
2238
2239         if (proto == PPP_COMP) {
2240                 int obuff_size;
2241
2242                 switch(ppp->rcomp->compress_proto) {
2243                 case CI_MPPE:
2244                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2245                         break;
2246                 default:
2247                         obuff_size = ppp->mru + PPP_HDRLEN;
2248                         break;
2249                 }
2250
2251                 ns = dev_alloc_skb(obuff_size);
2252                 if (!ns) {
2253                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2254                                    "no memory\n");
2255                         goto err;
2256                 }
2257                 /* the decompressor still expects the A/C bytes in the hdr */
2258                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2259                                 skb->len + 2, ns->data, obuff_size);
2260                 if (len < 0) {
2261                         /* Pass the compressed frame to pppd as an
2262                            error indication. */
2263                         if (len == DECOMP_FATALERROR)
2264                                 ppp->rstate |= SC_DC_FERROR;
2265                         kfree_skb(ns);
2266                         goto err;
2267                 }
2268
2269                 consume_skb(skb);
2270                 skb = ns;
2271                 skb_put(skb, len);
2272                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2273
2274         } else {
2275                 /* Uncompressed frame - pass to decompressor so it
2276                    can update its dictionary if necessary. */
2277                 if (ppp->rcomp->incomp)
2278                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2279                                            skb->len + 2);
2280         }
2281
2282         return skb;
2283
2284  err:
2285         ppp->rstate |= SC_DC_ERROR;
2286         ppp_receive_error(ppp);
2287         return skb;
2288 }
2289
2290 #ifdef CONFIG_PPP_MULTILINK
2291 /*
2292  * Receive a multilink frame.
2293  * We put it on the reconstruction queue and then pull off
2294  * as many completed frames as we can.
2295  */
2296 static void
2297 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2298 {
2299         u32 mask, seq;
2300         struct channel *ch;
2301         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2302
2303         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2304                 goto err;               /* no good, throw it away */
2305
2306         /* Decode sequence number and begin/end bits */
2307         if (ppp->flags & SC_MP_SHORTSEQ) {
2308                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2309                 mask = 0xfff;
2310         } else {
2311                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2312                 mask = 0xffffff;
2313         }
2314         PPP_MP_CB(skb)->BEbits = skb->data[2];
2315         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2316
2317         /*
2318          * Do protocol ID decompression on the first fragment of each packet.
2319          */
2320         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2321                 *skb_push(skb, 1) = 0;
2322
2323         /*
2324          * Expand sequence number to 32 bits, making it as close
2325          * as possible to ppp->minseq.
2326          */
2327         seq |= ppp->minseq & ~mask;
2328         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2329                 seq += mask + 1;
2330         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2331                 seq -= mask + 1;        /* should never happen */
2332         PPP_MP_CB(skb)->sequence = seq;
2333         pch->lastseq = seq;
2334
2335         /*
2336          * If this packet comes before the next one we were expecting,
2337          * drop it.
2338          */
2339         if (seq_before(seq, ppp->nextseq)) {
2340                 kfree_skb(skb);
2341                 ++ppp->dev->stats.rx_dropped;
2342                 ppp_receive_error(ppp);
2343                 return;
2344         }
2345
2346         /*
2347          * Reevaluate minseq, the minimum over all channels of the
2348          * last sequence number received on each channel.  Because of
2349          * the increasing sequence number rule, we know that any fragment
2350          * before `minseq' which hasn't arrived is never going to arrive.
2351          * The list of channels can't change because we have the receive
2352          * side of the ppp unit locked.
2353          */
2354         list_for_each_entry(ch, &ppp->channels, clist) {
2355                 if (seq_before(ch->lastseq, seq))
2356                         seq = ch->lastseq;
2357         }
2358         if (seq_before(ppp->minseq, seq))
2359                 ppp->minseq = seq;
2360
2361         /* Put the fragment on the reconstruction queue */
2362         ppp_mp_insert(ppp, skb);
2363
2364         /* If the queue is getting long, don't wait any longer for packets
2365            before the start of the queue. */
2366         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2367                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2368                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2369                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2370         }
2371
2372         /* Pull completed packets off the queue and receive them. */
2373         while ((skb = ppp_mp_reconstruct(ppp))) {
2374                 if (pskb_may_pull(skb, 2))
2375                         ppp_receive_nonmp_frame(ppp, skb);
2376                 else {
2377                         ++ppp->dev->stats.rx_length_errors;
2378                         kfree_skb(skb);
2379                         ppp_receive_error(ppp);
2380                 }
2381         }
2382
2383         return;
2384
2385  err:
2386         kfree_skb(skb);
2387         ppp_receive_error(ppp);
2388 }
2389
2390 /*
2391  * Insert a fragment on the MP reconstruction queue.
2392  * The queue is ordered by increasing sequence number.
2393  */
2394 static void
2395 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2396 {
2397         struct sk_buff *p;
2398         struct sk_buff_head *list = &ppp->mrq;
2399         u32 seq = PPP_MP_CB(skb)->sequence;
2400
2401         /* N.B. we don't need to lock the list lock because we have the
2402            ppp unit receive-side lock. */
2403         skb_queue_walk(list, p) {
2404                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2405                         break;
2406         }
2407         __skb_queue_before(list, p, skb);
2408 }
2409
2410 /*
2411  * Reconstruct a packet from the MP fragment queue.
2412  * We go through increasing sequence numbers until we find a
2413  * complete packet, or we get to the sequence number for a fragment
2414  * which hasn't arrived but might still do so.
2415  */
2416 static struct sk_buff *
2417 ppp_mp_reconstruct(struct ppp *ppp)
2418 {
2419         u32 seq = ppp->nextseq;
2420         u32 minseq = ppp->minseq;
2421         struct sk_buff_head *list = &ppp->mrq;
2422         struct sk_buff *p, *tmp;
2423         struct sk_buff *head, *tail;
2424         struct sk_buff *skb = NULL;
2425         int lost = 0, len = 0;
2426
2427         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2428                 return NULL;
2429         head = list->next;
2430         tail = NULL;
2431         skb_queue_walk_safe(list, p, tmp) {
2432         again:
2433                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2434                         /* this can't happen, anyway ignore the skb */
2435                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2436                                    "seq %u < %u\n",
2437                                    PPP_MP_CB(p)->sequence, seq);
2438                         __skb_unlink(p, list);
2439                         kfree_skb(p);
2440                         continue;
2441                 }
2442                 if (PPP_MP_CB(p)->sequence != seq) {
2443                         u32 oldseq;
2444                         /* Fragment `seq' is missing.  If it is after
2445                            minseq, it might arrive later, so stop here. */
2446                         if (seq_after(seq, minseq))
2447                                 break;
2448                         /* Fragment `seq' is lost, keep going. */
2449                         lost = 1;
2450                         oldseq = seq;
2451                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2452                                 minseq + 1: PPP_MP_CB(p)->sequence;
2453
2454                         if (ppp->debug & 1)
2455                                 netdev_printk(KERN_DEBUG, ppp->dev,
2456                                               "lost frag %u..%u\n",
2457                                               oldseq, seq-1);
2458
2459                         goto again;
2460                 }
2461
2462                 /*
2463                  * At this point we know that all the fragments from
2464                  * ppp->nextseq to seq are either present or lost.
2465                  * Also, there are no complete packets in the queue
2466                  * that have no missing fragments and end before this
2467                  * fragment.
2468                  */
2469
2470                 /* B bit set indicates this fragment starts a packet */
2471                 if (PPP_MP_CB(p)->BEbits & B) {
2472                         head = p;
2473                         lost = 0;
2474                         len = 0;
2475                 }
2476
2477                 len += p->len;
2478
2479                 /* Got a complete packet yet? */
2480                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2481                     (PPP_MP_CB(head)->BEbits & B)) {
2482                         if (len > ppp->mrru + 2) {
2483                                 ++ppp->dev->stats.rx_length_errors;
2484                                 netdev_printk(KERN_DEBUG, ppp->dev,
2485                                               "PPP: reconstructed packet"
2486                                               " is too long (%d)\n", len);
2487                         } else {
2488                                 tail = p;
2489                                 break;
2490                         }
2491                         ppp->nextseq = seq + 1;
2492                 }
2493
2494                 /*
2495                  * If this is the ending fragment of a packet,
2496                  * and we haven't found a complete valid packet yet,
2497                  * we can discard up to and including this fragment.
2498                  */
2499                 if (PPP_MP_CB(p)->BEbits & E) {
2500                         struct sk_buff *tmp2;
2501
2502                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2503                                 if (ppp->debug & 1)
2504                                         netdev_printk(KERN_DEBUG, ppp->dev,
2505                                                       "discarding frag %u\n",
2506                                                       PPP_MP_CB(p)->sequence);
2507                                 __skb_unlink(p, list);
2508                                 kfree_skb(p);
2509                         }
2510                         head = skb_peek(list);
2511                         if (!head)
2512                                 break;
2513                 }
2514                 ++seq;
2515         }
2516
2517         /* If we have a complete packet, copy it all into one skb. */
2518         if (tail != NULL) {
2519                 /* If we have discarded any fragments,
2520                    signal a receive error. */
2521                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2522                         skb_queue_walk_safe(list, p, tmp) {
2523                                 if (p == head)
2524                                         break;
2525                                 if (ppp->debug & 1)
2526                                         netdev_printk(KERN_DEBUG, ppp->dev,
2527                                                       "discarding frag %u\n",
2528                                                       PPP_MP_CB(p)->sequence);
2529                                 __skb_unlink(p, list);
2530                                 kfree_skb(p);
2531                         }
2532
2533                         if (ppp->debug & 1)
2534                                 netdev_printk(KERN_DEBUG, ppp->dev,
2535                                               "  missed pkts %u..%u\n",
2536                                               ppp->nextseq,
2537                                               PPP_MP_CB(head)->sequence-1);
2538                         ++ppp->dev->stats.rx_dropped;
2539                         ppp_receive_error(ppp);
2540                 }
2541
2542                 skb = head;
2543                 if (head != tail) {
2544                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2545                         p = skb_queue_next(list, head);
2546                         __skb_unlink(skb, list);
2547                         skb_queue_walk_from_safe(list, p, tmp) {
2548                                 __skb_unlink(p, list);
2549                                 *fragpp = p;
2550                                 p->next = NULL;
2551                                 fragpp = &p->next;
2552
2553                                 skb->len += p->len;
2554                                 skb->data_len += p->len;
2555                                 skb->truesize += p->truesize;
2556
2557                                 if (p == tail)
2558                                         break;
2559                         }
2560                 } else {
2561                         __skb_unlink(skb, list);
2562                 }
2563
2564                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2565         }
2566
2567         return skb;
2568 }
2569 #endif /* CONFIG_PPP_MULTILINK */
2570
2571 /*
2572  * Channel interface.
2573  */
2574
2575 /* Create a new, unattached ppp channel. */
2576 int ppp_register_channel(struct ppp_channel *chan)
2577 {
2578         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2579 }
2580
2581 /* Create a new, unattached ppp channel for specified net. */
2582 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2583 {
2584         struct channel *pch;
2585         struct ppp_net *pn;
2586
2587         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2588         if (!pch)
2589                 return -ENOMEM;
2590
2591         pn = ppp_pernet(net);
2592
2593         pch->ppp = NULL;
2594         pch->chan = chan;
2595         pch->chan_net = get_net(net);
2596         chan->ppp = pch;
2597         init_ppp_file(&pch->file, CHANNEL);
2598         pch->file.hdrlen = chan->hdrlen;
2599 #ifdef CONFIG_PPP_MULTILINK
2600         pch->lastseq = -1;
2601 #endif /* CONFIG_PPP_MULTILINK */
2602         init_rwsem(&pch->chan_sem);
2603         spin_lock_init(&pch->downl);
2604         rwlock_init(&pch->upl);
2605
2606         spin_lock_bh(&pn->all_channels_lock);
2607         pch->file.index = ++pn->last_channel_index;
2608         list_add(&pch->list, &pn->new_channels);
2609         atomic_inc(&channel_count);
2610         spin_unlock_bh(&pn->all_channels_lock);
2611
2612         return 0;
2613 }
2614
2615 /*
2616  * Return the index of a channel.
2617  */
2618 int ppp_channel_index(struct ppp_channel *chan)
2619 {
2620         struct channel *pch = chan->ppp;
2621
2622         if (pch)
2623                 return pch->file.index;
2624         return -1;
2625 }
2626
2627 /*
2628  * Return the PPP unit number to which a channel is connected.
2629  */
2630 int ppp_unit_number(struct ppp_channel *chan)
2631 {
2632         struct channel *pch = chan->ppp;
2633         int unit = -1;
2634
2635         if (pch) {
2636                 read_lock_bh(&pch->upl);
2637                 if (pch->ppp)
2638                         unit = pch->ppp->file.index;
2639                 read_unlock_bh(&pch->upl);
2640         }
2641         return unit;
2642 }
2643
2644 /*
2645  * Return the PPP device interface name of a channel.
2646  */
2647 char *ppp_dev_name(struct ppp_channel *chan)
2648 {
2649         struct channel *pch = chan->ppp;
2650         char *name = NULL;
2651
2652         if (pch) {
2653                 read_lock_bh(&pch->upl);
2654                 if (pch->ppp && pch->ppp->dev)
2655                         name = pch->ppp->dev->name;
2656                 read_unlock_bh(&pch->upl);
2657         }
2658         return name;
2659 }
2660
2661
2662 /*
2663  * Disconnect a channel from the generic layer.
2664  * This must be called in process context.
2665  */
2666 void
2667 ppp_unregister_channel(struct ppp_channel *chan)
2668 {
2669         struct channel *pch = chan->ppp;
2670         struct ppp_net *pn;
2671
2672         if (!pch)
2673                 return;         /* should never happen */
2674
2675         chan->ppp = NULL;
2676
2677         /*
2678          * This ensures that we have returned from any calls into the
2679          * the channel's start_xmit or ioctl routine before we proceed.
2680          */
2681         down_write(&pch->chan_sem);
2682         spin_lock_bh(&pch->downl);
2683         pch->chan = NULL;
2684         spin_unlock_bh(&pch->downl);
2685         up_write(&pch->chan_sem);
2686         ppp_disconnect_channel(pch);
2687
2688         pn = ppp_pernet(pch->chan_net);
2689         spin_lock_bh(&pn->all_channels_lock);
2690         list_del(&pch->list);
2691         spin_unlock_bh(&pn->all_channels_lock);
2692
2693         pch->file.dead = 1;
2694         wake_up_interruptible(&pch->file.rwait);
2695         if (atomic_dec_and_test(&pch->file.refcnt))
2696                 ppp_destroy_channel(pch);
2697 }
2698
2699 /*
2700  * Callback from a channel when it can accept more to transmit.
2701  * This should be called at BH/softirq level, not interrupt level.
2702  */
2703 void
2704 ppp_output_wakeup(struct ppp_channel *chan)
2705 {
2706         struct channel *pch = chan->ppp;
2707
2708         if (!pch)
2709                 return;
2710         ppp_channel_push(pch);
2711 }
2712
2713 /*
2714  * Compression control.
2715  */
2716
2717 /* Process the PPPIOCSCOMPRESS ioctl. */
2718 static int
2719 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2720 {
2721         int err;
2722         struct compressor *cp, *ocomp;
2723         struct ppp_option_data data;
2724         void *state, *ostate;
2725         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2726
2727         err = -EFAULT;
2728         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2729                 goto out;
2730         if (data.length > CCP_MAX_OPTION_LENGTH)
2731                 goto out;
2732         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2733                 goto out;
2734
2735         err = -EINVAL;
2736         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2737                 goto out;
2738
2739         cp = try_then_request_module(
2740                 find_compressor(ccp_option[0]),
2741                 "ppp-compress-%d", ccp_option[0]);
2742         if (!cp)
2743                 goto out;
2744
2745         err = -ENOBUFS;
2746         if (data.transmit) {
2747                 state = cp->comp_alloc(ccp_option, data.length);
2748                 if (state) {
2749                         ppp_xmit_lock(ppp);
2750                         ppp->xstate &= ~SC_COMP_RUN;
2751                         ocomp = ppp->xcomp;
2752                         ostate = ppp->xc_state;
2753                         ppp->xcomp = cp;
2754                         ppp->xc_state = state;
2755                         ppp_xmit_unlock(ppp);
2756                         if (ostate) {
2757                                 ocomp->comp_free(ostate);
2758                                 module_put(ocomp->owner);
2759                         }
2760                         err = 0;
2761                 } else
2762                         module_put(cp->owner);
2763
2764         } else {
2765                 state = cp->decomp_alloc(ccp_option, data.length);
2766                 if (state) {
2767                         ppp_recv_lock(ppp);
2768                         ppp->rstate &= ~SC_DECOMP_RUN;
2769                         ocomp = ppp->rcomp;
2770                         ostate = ppp->rc_state;
2771                         ppp->rcomp = cp;
2772                         ppp->rc_state = state;
2773                         ppp_recv_unlock(ppp);
2774                         if (ostate) {
2775                                 ocomp->decomp_free(ostate);
2776                                 module_put(ocomp->owner);
2777                         }
2778                         err = 0;
2779                 } else
2780                         module_put(cp->owner);
2781         }
2782
2783  out:
2784         return err;
2785 }
2786
2787 /*
2788  * Look at a CCP packet and update our state accordingly.
2789  * We assume the caller has the xmit or recv path locked.
2790  */
2791 static void
2792 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2793 {
2794         unsigned char *dp;
2795         int len;
2796
2797         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2798                 return; /* no header */
2799         dp = skb->data + 2;
2800
2801         switch (CCP_CODE(dp)) {
2802         case CCP_CONFREQ:
2803
2804                 /* A ConfReq starts negotiation of compression
2805                  * in one direction of transmission,
2806                  * and hence brings it down...but which way?
2807                  *
2808                  * Remember:
2809                  * A ConfReq indicates what the sender would like to receive
2810                  */
2811                 if(inbound)
2812                         /* He is proposing what I should send */
2813                         ppp->xstate &= ~SC_COMP_RUN;
2814                 else
2815                         /* I am proposing to what he should send */
2816                         ppp->rstate &= ~SC_DECOMP_RUN;
2817
2818                 break;
2819
2820         case CCP_TERMREQ:
2821         case CCP_TERMACK:
2822                 /*
2823                  * CCP is going down, both directions of transmission
2824                  */
2825                 ppp->rstate &= ~SC_DECOMP_RUN;
2826                 ppp->xstate &= ~SC_COMP_RUN;
2827                 break;
2828
2829         case CCP_CONFACK:
2830                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2831                         break;
2832                 len = CCP_LENGTH(dp);
2833                 if (!pskb_may_pull(skb, len + 2))
2834                         return;         /* too short */
2835                 dp += CCP_HDRLEN;
2836                 len -= CCP_HDRLEN;
2837                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2838                         break;
2839                 if (inbound) {
2840                         /* we will start receiving compressed packets */
2841                         if (!ppp->rc_state)
2842                                 break;
2843                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2844                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2845                                 ppp->rstate |= SC_DECOMP_RUN;
2846                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2847                         }
2848                 } else {
2849                         /* we will soon start sending compressed packets */
2850                         if (!ppp->xc_state)
2851                                 break;
2852                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2853                                         ppp->file.index, 0, ppp->debug))
2854                                 ppp->xstate |= SC_COMP_RUN;
2855                 }
2856                 break;
2857
2858         case CCP_RESETACK:
2859                 /* reset the [de]compressor */
2860                 if ((ppp->flags & SC_CCP_UP) == 0)
2861                         break;
2862                 if (inbound) {
2863                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2864                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2865                                 ppp->rstate &= ~SC_DC_ERROR;
2866                         }
2867                 } else {
2868                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2869                                 ppp->xcomp->comp_reset(ppp->xc_state);
2870                 }
2871                 break;
2872         }
2873 }
2874
2875 /* Free up compression resources. */
2876 static void
2877 ppp_ccp_closed(struct ppp *ppp)
2878 {
2879         void *xstate, *rstate;
2880         struct compressor *xcomp, *rcomp;
2881
2882         ppp_lock(ppp);
2883         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2884         ppp->xstate = 0;
2885         xcomp = ppp->xcomp;
2886         xstate = ppp->xc_state;
2887         ppp->xc_state = NULL;
2888         ppp->rstate = 0;
2889         rcomp = ppp->rcomp;
2890         rstate = ppp->rc_state;
2891         ppp->rc_state = NULL;
2892         ppp_unlock(ppp);
2893
2894         if (xstate) {
2895                 xcomp->comp_free(xstate);
2896                 module_put(xcomp->owner);
2897         }
2898         if (rstate) {
2899                 rcomp->decomp_free(rstate);
2900                 module_put(rcomp->owner);
2901         }
2902 }
2903
2904 /* List of compressors. */
2905 static LIST_HEAD(compressor_list);
2906 static DEFINE_SPINLOCK(compressor_list_lock);
2907
2908 struct compressor_entry {
2909         struct list_head list;
2910         struct compressor *comp;
2911 };
2912
2913 static struct compressor_entry *
2914 find_comp_entry(int proto)
2915 {
2916         struct compressor_entry *ce;
2917
2918         list_for_each_entry(ce, &compressor_list, list) {
2919                 if (ce->comp->compress_proto == proto)
2920                         return ce;
2921         }
2922         return NULL;
2923 }
2924
2925 /* Register a compressor */
2926 int
2927 ppp_register_compressor(struct compressor *cp)
2928 {
2929         struct compressor_entry *ce;
2930         int ret;
2931         spin_lock(&compressor_list_lock);
2932         ret = -EEXIST;
2933         if (find_comp_entry(cp->compress_proto))
2934                 goto out;
2935         ret = -ENOMEM;
2936         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2937         if (!ce)
2938                 goto out;
2939         ret = 0;
2940         ce->comp = cp;
2941         list_add(&ce->list, &compressor_list);
2942  out:
2943         spin_unlock(&compressor_list_lock);
2944         return ret;
2945 }
2946
2947 /* Unregister a compressor */
2948 void
2949 ppp_unregister_compressor(struct compressor *cp)
2950 {
2951         struct compressor_entry *ce;
2952
2953         spin_lock(&compressor_list_lock);
2954         ce = find_comp_entry(cp->compress_proto);
2955         if (ce && ce->comp == cp) {
2956                 list_del(&ce->list);
2957                 kfree(ce);
2958         }
2959         spin_unlock(&compressor_list_lock);
2960 }
2961
2962 /* Find a compressor. */
2963 static struct compressor *
2964 find_compressor(int type)
2965 {
2966         struct compressor_entry *ce;
2967         struct compressor *cp = NULL;
2968
2969         spin_lock(&compressor_list_lock);
2970         ce = find_comp_entry(type);
2971         if (ce) {
2972                 cp = ce->comp;
2973                 if (!try_module_get(cp->owner))
2974                         cp = NULL;
2975         }
2976         spin_unlock(&compressor_list_lock);
2977         return cp;
2978 }
2979
2980 /*
2981  * Miscelleneous stuff.
2982  */
2983
2984 static void
2985 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2986 {
2987         struct slcompress *vj = ppp->vj;
2988
2989         memset(st, 0, sizeof(*st));
2990         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2991         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2992         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2993         st->p.ppp_opackets = ppp->stats64.tx_packets;
2994         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2995         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2996         if (!vj)
2997                 return;
2998         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2999         st->vj.vjs_compressed = vj->sls_o_compressed;
3000         st->vj.vjs_searches = vj->sls_o_searches;
3001         st->vj.vjs_misses = vj->sls_o_misses;
3002         st->vj.vjs_errorin = vj->sls_i_error;
3003         st->vj.vjs_tossed = vj->sls_i_tossed;
3004         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3005         st->vj.vjs_compressedin = vj->sls_i_compressed;
3006 }
3007
3008 /*
3009  * Stuff for handling the lists of ppp units and channels
3010  * and for initialization.
3011  */
3012
3013 /*
3014  * Create a new ppp interface unit.  Fails if it can't allocate memory
3015  * or if there is already a unit with the requested number.
3016  * unit == -1 means allocate a new number.
3017  */
3018 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3019 {
3020         struct ppp_config conf = {
3021                 .file = file,
3022                 .unit = *unit,
3023                 .ifname_is_set = false,
3024         };
3025         struct net_device *dev;
3026         struct ppp *ppp;
3027         int err;
3028
3029         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3030         if (!dev) {
3031                 err = -ENOMEM;
3032                 goto err;
3033         }
3034         dev_net_set(dev, net);
3035         dev->rtnl_link_ops = &ppp_link_ops;
3036
3037         rtnl_lock();
3038
3039         err = ppp_dev_configure(net, dev, &conf);
3040         if (err < 0)
3041                 goto err_dev;
3042         ppp = netdev_priv(dev);
3043         *unit = ppp->file.index;
3044
3045         rtnl_unlock();
3046
3047         return 0;
3048
3049 err_dev:
3050         rtnl_unlock();
3051         free_netdev(dev);
3052 err:
3053         return err;
3054 }
3055
3056 /*
3057  * Initialize a ppp_file structure.
3058  */
3059 static void
3060 init_ppp_file(struct ppp_file *pf, int kind)
3061 {
3062         pf->kind = kind;
3063         skb_queue_head_init(&pf->xq);
3064         skb_queue_head_init(&pf->rq);
3065         atomic_set(&pf->refcnt, 1);
3066         init_waitqueue_head(&pf->rwait);
3067 }
3068
3069 /*
3070  * Free the memory used by a ppp unit.  This is only called once
3071  * there are no channels connected to the unit and no file structs
3072  * that reference the unit.
3073  */
3074 static void ppp_destroy_interface(struct ppp *ppp)
3075 {
3076         atomic_dec(&ppp_unit_count);
3077
3078         if (!ppp->file.dead || ppp->n_channels) {
3079                 /* "can't happen" */
3080                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3081                            "but dead=%d n_channels=%d !\n",
3082                            ppp, ppp->file.dead, ppp->n_channels);
3083                 return;
3084         }
3085
3086         ppp_ccp_closed(ppp);
3087         if (ppp->vj) {
3088                 slhc_free(ppp->vj);
3089                 ppp->vj = NULL;
3090         }
3091         skb_queue_purge(&ppp->file.xq);
3092         skb_queue_purge(&ppp->file.rq);
3093 #ifdef CONFIG_PPP_MULTILINK
3094         skb_queue_purge(&ppp->mrq);
3095 #endif /* CONFIG_PPP_MULTILINK */
3096 #ifdef CONFIG_PPP_FILTER
3097         if (ppp->pass_filter) {
3098                 bpf_prog_destroy(ppp->pass_filter);
3099                 ppp->pass_filter = NULL;
3100         }
3101
3102         if (ppp->active_filter) {
3103                 bpf_prog_destroy(ppp->active_filter);
3104                 ppp->active_filter = NULL;
3105         }
3106 #endif /* CONFIG_PPP_FILTER */
3107
3108         kfree_skb(ppp->xmit_pending);
3109         free_percpu(ppp->xmit_recursion);
3110
3111         free_netdev(ppp->dev);
3112 }
3113
3114 /*
3115  * Locate an existing ppp unit.
3116  * The caller should have locked the all_ppp_mutex.
3117  */
3118 static struct ppp *
3119 ppp_find_unit(struct ppp_net *pn, int unit)
3120 {
3121         return unit_find(&pn->units_idr, unit);
3122 }
3123
3124 /*
3125  * Locate an existing ppp channel.
3126  * The caller should have locked the all_channels_lock.
3127  * First we look in the new_channels list, then in the
3128  * all_channels list.  If found in the new_channels list,
3129  * we move it to the all_channels list.  This is for speed
3130  * when we have a lot of channels in use.
3131  */
3132 static struct channel *
3133 ppp_find_channel(struct ppp_net *pn, int unit)
3134 {
3135         struct channel *pch;
3136
3137         list_for_each_entry(pch, &pn->new_channels, list) {
3138                 if (pch->file.index == unit) {
3139                         list_move(&pch->list, &pn->all_channels);
3140                         return pch;
3141                 }
3142         }
3143
3144         list_for_each_entry(pch, &pn->all_channels, list) {
3145                 if (pch->file.index == unit)
3146                         return pch;
3147         }
3148
3149         return NULL;
3150 }
3151
3152 /*
3153  * Connect a PPP channel to a PPP interface unit.
3154  */
3155 static int
3156 ppp_connect_channel(struct channel *pch, int unit)
3157 {
3158         struct ppp *ppp;
3159         struct ppp_net *pn;
3160         int ret = -ENXIO;
3161         int hdrlen;
3162
3163         pn = ppp_pernet(pch->chan_net);
3164
3165         mutex_lock(&pn->all_ppp_mutex);
3166         ppp = ppp_find_unit(pn, unit);
3167         if (!ppp)
3168                 goto out;
3169         write_lock_bh(&pch->upl);
3170         ret = -EINVAL;
3171         if (pch->ppp)
3172                 goto outl;
3173
3174         ppp_lock(ppp);
3175         spin_lock_bh(&pch->downl);
3176         if (!pch->chan) {
3177                 /* Don't connect unregistered channels */
3178                 spin_unlock_bh(&pch->downl);
3179                 ppp_unlock(ppp);
3180                 ret = -ENOTCONN;
3181                 goto outl;
3182         }
3183         spin_unlock_bh(&pch->downl);
3184         if (pch->file.hdrlen > ppp->file.hdrlen)
3185                 ppp->file.hdrlen = pch->file.hdrlen;
3186         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3187         if (hdrlen > ppp->dev->hard_header_len)
3188                 ppp->dev->hard_header_len = hdrlen;
3189         list_add_tail(&pch->clist, &ppp->channels);
3190         ++ppp->n_channels;
3191         pch->ppp = ppp;
3192         atomic_inc(&ppp->file.refcnt);
3193         ppp_unlock(ppp);
3194         ret = 0;
3195
3196  outl:
3197         write_unlock_bh(&pch->upl);
3198  out:
3199         mutex_unlock(&pn->all_ppp_mutex);
3200         return ret;
3201 }
3202
3203 /*
3204  * Disconnect a channel from its ppp unit.
3205  */
3206 static int
3207 ppp_disconnect_channel(struct channel *pch)
3208 {
3209         struct ppp *ppp;
3210         int err = -EINVAL;
3211
3212         write_lock_bh(&pch->upl);
3213         ppp = pch->ppp;
3214         pch->ppp = NULL;
3215         write_unlock_bh(&pch->upl);
3216         if (ppp) {
3217                 /* remove it from the ppp unit's list */
3218                 ppp_lock(ppp);
3219                 list_del(&pch->clist);
3220                 if (--ppp->n_channels == 0)
3221                         wake_up_interruptible(&ppp->file.rwait);
3222                 ppp_unlock(ppp);
3223                 if (atomic_dec_and_test(&ppp->file.refcnt))
3224                         ppp_destroy_interface(ppp);
3225                 err = 0;
3226         }
3227         return err;
3228 }
3229
3230 /*
3231  * Free up the resources used by a ppp channel.
3232  */
3233 static void ppp_destroy_channel(struct channel *pch)
3234 {
3235         put_net(pch->chan_net);
3236         pch->chan_net = NULL;
3237
3238         atomic_dec(&channel_count);
3239
3240         if (!pch->file.dead) {
3241                 /* "can't happen" */
3242                 pr_err("ppp: destroying undead channel %p !\n", pch);
3243                 return;
3244         }
3245         skb_queue_purge(&pch->file.xq);
3246         skb_queue_purge(&pch->file.rq);
3247         kfree(pch);
3248 }
3249
3250 static void __exit ppp_cleanup(void)
3251 {
3252         /* should never happen */
3253         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3254                 pr_err("PPP: removing module but units remain!\n");
3255         rtnl_link_unregister(&ppp_link_ops);
3256         unregister_chrdev(PPP_MAJOR, "ppp");
3257         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3258         class_destroy(ppp_class);
3259         unregister_pernet_device(&ppp_net_ops);
3260 }
3261
3262 /*
3263  * Units handling. Caller must protect concurrent access
3264  * by holding all_ppp_mutex
3265  */
3266
3267 /* associate pointer with specified number */
3268 static int unit_set(struct idr *p, void *ptr, int n)
3269 {
3270         int unit;
3271
3272         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3273         if (unit == -ENOSPC)
3274                 unit = -EINVAL;
3275         return unit;
3276 }
3277
3278 /* get new free unit number and associate pointer with it */
3279 static int unit_get(struct idr *p, void *ptr, int min)
3280 {
3281         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3282 }
3283
3284 /* put unit number back to a pool */
3285 static void unit_put(struct idr *p, int n)
3286 {
3287         idr_remove(p, n);
3288 }
3289
3290 /* get pointer associated with the number */
3291 static void *unit_find(struct idr *p, int n)
3292 {
3293         return idr_find(p, n);
3294 }
3295
3296 /* Module/initialization stuff */
3297
3298 module_init(ppp_init);
3299 module_exit(ppp_cleanup);
3300
3301 EXPORT_SYMBOL(ppp_register_net_channel);
3302 EXPORT_SYMBOL(ppp_register_channel);
3303 EXPORT_SYMBOL(ppp_unregister_channel);
3304 EXPORT_SYMBOL(ppp_channel_index);
3305 EXPORT_SYMBOL(ppp_unit_number);
3306 EXPORT_SYMBOL(ppp_dev_name);
3307 EXPORT_SYMBOL(ppp_input);
3308 EXPORT_SYMBOL(ppp_input_error);
3309 EXPORT_SYMBOL(ppp_output_wakeup);
3310 EXPORT_SYMBOL(ppp_register_compressor);
3311 EXPORT_SYMBOL(ppp_unregister_compressor);
3312 MODULE_LICENSE("GPL");
3313 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3314 MODULE_ALIAS_RTNL_LINK("ppp");
3315 MODULE_ALIAS("devname:ppp");