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