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             *xmit_recursion __percpu; /* 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         netdev_lockdep_set_classes(dev);
1343         return 0;
1344 }
1345
1346 static void ppp_dev_uninit(struct net_device *dev)
1347 {
1348         struct ppp *ppp = netdev_priv(dev);
1349         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1350
1351         ppp_lock(ppp);
1352         ppp->closing = 1;
1353         ppp_unlock(ppp);
1354
1355         mutex_lock(&pn->all_ppp_mutex);
1356         unit_put(&pn->units_idr, ppp->file.index);
1357         mutex_unlock(&pn->all_ppp_mutex);
1358
1359         ppp->owner = NULL;
1360
1361         ppp->file.dead = 1;
1362         wake_up_interruptible(&ppp->file.rwait);
1363 }
1364
1365 static const struct net_device_ops ppp_netdev_ops = {
1366         .ndo_init        = ppp_dev_init,
1367         .ndo_uninit      = ppp_dev_uninit,
1368         .ndo_start_xmit  = ppp_start_xmit,
1369         .ndo_do_ioctl    = ppp_net_ioctl,
1370         .ndo_get_stats64 = ppp_get_stats64,
1371 };
1372
1373 static struct device_type ppp_type = {
1374         .name = "ppp",
1375 };
1376
1377 static void ppp_setup(struct net_device *dev)
1378 {
1379         dev->netdev_ops = &ppp_netdev_ops;
1380         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1381
1382         dev->features |= NETIF_F_LLTX;
1383
1384         dev->hard_header_len = PPP_HDRLEN;
1385         dev->mtu = PPP_MRU;
1386         dev->addr_len = 0;
1387         dev->tx_queue_len = 3;
1388         dev->type = ARPHRD_PPP;
1389         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1390         netif_keep_dst(dev);
1391 }
1392
1393 /*
1394  * Transmit-side routines.
1395  */
1396
1397 /* Called to do any work queued up on the transmit side that can now be done */
1398 static void __ppp_xmit_process(struct ppp *ppp)
1399 {
1400         struct sk_buff *skb;
1401
1402         ppp_xmit_lock(ppp);
1403         if (!ppp->closing) {
1404                 ppp_push(ppp);
1405                 while (!ppp->xmit_pending &&
1406                        (skb = skb_dequeue(&ppp->file.xq)))
1407                         ppp_send_frame(ppp, skb);
1408                 /* If there's no work left to do, tell the core net
1409                    code that we can accept some more. */
1410                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1411                         netif_wake_queue(ppp->dev);
1412                 else
1413                         netif_stop_queue(ppp->dev);
1414         }
1415         ppp_xmit_unlock(ppp);
1416 }
1417
1418 static void ppp_xmit_process(struct ppp *ppp)
1419 {
1420         local_bh_disable();
1421
1422         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1423                 goto err;
1424
1425         (*this_cpu_ptr(ppp->xmit_recursion))++;
1426         __ppp_xmit_process(ppp);
1427         (*this_cpu_ptr(ppp->xmit_recursion))--;
1428
1429         local_bh_enable();
1430
1431         return;
1432
1433 err:
1434         local_bh_enable();
1435
1436         if (net_ratelimit())
1437                 netdev_err(ppp->dev, "recursion detected\n");
1438 }
1439
1440 static inline struct sk_buff *
1441 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1442 {
1443         struct sk_buff *new_skb;
1444         int len;
1445         int new_skb_size = ppp->dev->mtu +
1446                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1447         int compressor_skb_size = ppp->dev->mtu +
1448                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1449         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1450         if (!new_skb) {
1451                 if (net_ratelimit())
1452                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1453                 return NULL;
1454         }
1455         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1456                 skb_reserve(new_skb,
1457                             ppp->dev->hard_header_len - PPP_HDRLEN);
1458
1459         /* compressor still expects A/C bytes in hdr */
1460         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1461                                    new_skb->data, skb->len + 2,
1462                                    compressor_skb_size);
1463         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1464                 consume_skb(skb);
1465                 skb = new_skb;
1466                 skb_put(skb, len);
1467                 skb_pull(skb, 2);       /* pull off A/C bytes */
1468         } else if (len == 0) {
1469                 /* didn't compress, or CCP not up yet */
1470                 consume_skb(new_skb);
1471                 new_skb = skb;
1472         } else {
1473                 /*
1474                  * (len < 0)
1475                  * MPPE requires that we do not send unencrypted
1476                  * frames.  The compressor will return -1 if we
1477                  * should drop the frame.  We cannot simply test
1478                  * the compress_proto because MPPE and MPPC share
1479                  * the same number.
1480                  */
1481                 if (net_ratelimit())
1482                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1483                 kfree_skb(skb);
1484                 consume_skb(new_skb);
1485                 new_skb = NULL;
1486         }
1487         return new_skb;
1488 }
1489
1490 /*
1491  * Compress and send a frame.
1492  * The caller should have locked the xmit path,
1493  * and xmit_pending should be 0.
1494  */
1495 static void
1496 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1497 {
1498         int proto = PPP_PROTO(skb);
1499         struct sk_buff *new_skb;
1500         int len;
1501         unsigned char *cp;
1502
1503         if (proto < 0x8000) {
1504 #ifdef CONFIG_PPP_FILTER
1505                 /* check if we should pass this packet */
1506                 /* the filter instructions are constructed assuming
1507                    a four-byte PPP header on each packet */
1508                 *(u8 *)skb_push(skb, 2) = 1;
1509                 if (ppp->pass_filter &&
1510                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1511                         if (ppp->debug & 1)
1512                                 netdev_printk(KERN_DEBUG, ppp->dev,
1513                                               "PPP: outbound frame "
1514                                               "not passed\n");
1515                         kfree_skb(skb);
1516                         return;
1517                 }
1518                 /* if this packet passes the active filter, record the time */
1519                 if (!(ppp->active_filter &&
1520                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1521                         ppp->last_xmit = jiffies;
1522                 skb_pull(skb, 2);
1523 #else
1524                 /* for data packets, record the time */
1525                 ppp->last_xmit = jiffies;
1526 #endif /* CONFIG_PPP_FILTER */
1527         }
1528
1529         ++ppp->stats64.tx_packets;
1530         ppp->stats64.tx_bytes += skb->len - 2;
1531
1532         switch (proto) {
1533         case PPP_IP:
1534                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1535                         break;
1536                 /* try to do VJ TCP header compression */
1537                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1538                                     GFP_ATOMIC);
1539                 if (!new_skb) {
1540                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1541                         goto drop;
1542                 }
1543                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1544                 cp = skb->data + 2;
1545                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1546                                     new_skb->data + 2, &cp,
1547                                     !(ppp->flags & SC_NO_TCP_CCID));
1548                 if (cp == skb->data + 2) {
1549                         /* didn't compress */
1550                         consume_skb(new_skb);
1551                 } else {
1552                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1553                                 proto = PPP_VJC_COMP;
1554                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1555                         } else {
1556                                 proto = PPP_VJC_UNCOMP;
1557                                 cp[0] = skb->data[2];
1558                         }
1559                         consume_skb(skb);
1560                         skb = new_skb;
1561                         cp = skb_put(skb, len + 2);
1562                         cp[0] = 0;
1563                         cp[1] = proto;
1564                 }
1565                 break;
1566
1567         case PPP_CCP:
1568                 /* peek at outbound CCP frames */
1569                 ppp_ccp_peek(ppp, skb, 0);
1570                 break;
1571         }
1572
1573         /* try to do packet compression */
1574         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1575             proto != PPP_LCP && proto != PPP_CCP) {
1576                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1577                         if (net_ratelimit())
1578                                 netdev_err(ppp->dev,
1579                                            "ppp: compression required but "
1580                                            "down - pkt dropped.\n");
1581                         goto drop;
1582                 }
1583                 skb = pad_compress_skb(ppp, skb);
1584                 if (!skb)
1585                         goto drop;
1586         }
1587
1588         /*
1589          * If we are waiting for traffic (demand dialling),
1590          * queue it up for pppd to receive.
1591          */
1592         if (ppp->flags & SC_LOOP_TRAFFIC) {
1593                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1594                         goto drop;
1595                 skb_queue_tail(&ppp->file.rq, skb);
1596                 wake_up_interruptible(&ppp->file.rwait);
1597                 return;
1598         }
1599
1600         ppp->xmit_pending = skb;
1601         ppp_push(ppp);
1602         return;
1603
1604  drop:
1605         kfree_skb(skb);
1606         ++ppp->dev->stats.tx_errors;
1607 }
1608
1609 /*
1610  * Try to send the frame in xmit_pending.
1611  * The caller should have the xmit path locked.
1612  */
1613 static void
1614 ppp_push(struct ppp *ppp)
1615 {
1616         struct list_head *list;
1617         struct channel *pch;
1618         struct sk_buff *skb = ppp->xmit_pending;
1619
1620         if (!skb)
1621                 return;
1622
1623         list = &ppp->channels;
1624         if (list_empty(list)) {
1625                 /* nowhere to send the packet, just drop it */
1626                 ppp->xmit_pending = NULL;
1627                 kfree_skb(skb);
1628                 return;
1629         }
1630
1631         if ((ppp->flags & SC_MULTILINK) == 0) {
1632                 /* not doing multilink: send it down the first channel */
1633                 list = list->next;
1634                 pch = list_entry(list, struct channel, clist);
1635
1636                 spin_lock(&pch->downl);
1637                 if (pch->chan) {
1638                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1639                                 ppp->xmit_pending = NULL;
1640                 } else {
1641                         /* channel got unregistered */
1642                         kfree_skb(skb);
1643                         ppp->xmit_pending = NULL;
1644                 }
1645                 spin_unlock(&pch->downl);
1646                 return;
1647         }
1648
1649 #ifdef CONFIG_PPP_MULTILINK
1650         /* Multilink: fragment the packet over as many links
1651            as can take the packet at the moment. */
1652         if (!ppp_mp_explode(ppp, skb))
1653                 return;
1654 #endif /* CONFIG_PPP_MULTILINK */
1655
1656         ppp->xmit_pending = NULL;
1657         kfree_skb(skb);
1658 }
1659
1660 #ifdef CONFIG_PPP_MULTILINK
1661 static bool mp_protocol_compress __read_mostly = true;
1662 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1663 MODULE_PARM_DESC(mp_protocol_compress,
1664                  "compress protocol id in multilink fragments");
1665
1666 /*
1667  * Divide a packet to be transmitted into fragments and
1668  * send them out the individual links.
1669  */
1670 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1671 {
1672         int len, totlen;
1673         int i, bits, hdrlen, mtu;
1674         int flen;
1675         int navail, nfree, nzero;
1676         int nbigger;
1677         int totspeed;
1678         int totfree;
1679         unsigned char *p, *q;
1680         struct list_head *list;
1681         struct channel *pch;
1682         struct sk_buff *frag;
1683         struct ppp_channel *chan;
1684
1685         totspeed = 0; /*total bitrate of the bundle*/
1686         nfree = 0; /* # channels which have no packet already queued */
1687         navail = 0; /* total # of usable channels (not deregistered) */
1688         nzero = 0; /* number of channels with zero speed associated*/
1689         totfree = 0; /*total # of channels available and
1690                                   *having no queued packets before
1691                                   *starting the fragmentation*/
1692
1693         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1694         i = 0;
1695         list_for_each_entry(pch, &ppp->channels, clist) {
1696                 if (pch->chan) {
1697                         pch->avail = 1;
1698                         navail++;
1699                         pch->speed = pch->chan->speed;
1700                 } else {
1701                         pch->avail = 0;
1702                 }
1703                 if (pch->avail) {
1704                         if (skb_queue_empty(&pch->file.xq) ||
1705                                 !pch->had_frag) {
1706                                         if (pch->speed == 0)
1707                                                 nzero++;
1708                                         else
1709                                                 totspeed += pch->speed;
1710
1711                                         pch->avail = 2;
1712                                         ++nfree;
1713                                         ++totfree;
1714                                 }
1715                         if (!pch->had_frag && i < ppp->nxchan)
1716                                 ppp->nxchan = i;
1717                 }
1718                 ++i;
1719         }
1720         /*
1721          * Don't start sending this packet unless at least half of
1722          * the channels are free.  This gives much better TCP
1723          * performance if we have a lot of channels.
1724          */
1725         if (nfree == 0 || nfree < navail / 2)
1726                 return 0; /* can't take now, leave it in xmit_pending */
1727
1728         /* Do protocol field compression */
1729         p = skb->data;
1730         len = skb->len;
1731         if (*p == 0 && mp_protocol_compress) {
1732                 ++p;
1733                 --len;
1734         }
1735
1736         totlen = len;
1737         nbigger = len % nfree;
1738
1739         /* skip to the channel after the one we last used
1740            and start at that one */
1741         list = &ppp->channels;
1742         for (i = 0; i < ppp->nxchan; ++i) {
1743                 list = list->next;
1744                 if (list == &ppp->channels) {
1745                         i = 0;
1746                         break;
1747                 }
1748         }
1749
1750         /* create a fragment for each channel */
1751         bits = B;
1752         while (len > 0) {
1753                 list = list->next;
1754                 if (list == &ppp->channels) {
1755                         i = 0;
1756                         continue;
1757                 }
1758                 pch = list_entry(list, struct channel, clist);
1759                 ++i;
1760                 if (!pch->avail)
1761                         continue;
1762
1763                 /*
1764                  * Skip this channel if it has a fragment pending already and
1765                  * we haven't given a fragment to all of the free channels.
1766                  */
1767                 if (pch->avail == 1) {
1768                         if (nfree > 0)
1769                                 continue;
1770                 } else {
1771                         pch->avail = 1;
1772                 }
1773
1774                 /* check the channel's mtu and whether it is still attached. */
1775                 spin_lock(&pch->downl);
1776                 if (pch->chan == NULL) {
1777                         /* can't use this channel, it's being deregistered */
1778                         if (pch->speed == 0)
1779                                 nzero--;
1780                         else
1781                                 totspeed -= pch->speed;
1782
1783                         spin_unlock(&pch->downl);
1784                         pch->avail = 0;
1785                         totlen = len;
1786                         totfree--;
1787                         nfree--;
1788                         if (--navail == 0)
1789                                 break;
1790                         continue;
1791                 }
1792
1793                 /*
1794                 *if the channel speed is not set divide
1795                 *the packet evenly among the free channels;
1796                 *otherwise divide it according to the speed
1797                 *of the channel we are going to transmit on
1798                 */
1799                 flen = len;
1800                 if (nfree > 0) {
1801                         if (pch->speed == 0) {
1802                                 flen = len/nfree;
1803                                 if (nbigger > 0) {
1804                                         flen++;
1805                                         nbigger--;
1806                                 }
1807                         } else {
1808                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1809                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1810                                 if (nbigger > 0) {
1811                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1812                                         nbigger -= ((totfree - nzero)*pch->speed)/
1813                                                         totspeed;
1814                                 }
1815                         }
1816                         nfree--;
1817                 }
1818
1819                 /*
1820                  *check if we are on the last channel or
1821                  *we exceded the length of the data to
1822                  *fragment
1823                  */
1824                 if ((nfree <= 0) || (flen > len))
1825                         flen = len;
1826                 /*
1827                  *it is not worth to tx on slow channels:
1828                  *in that case from the resulting flen according to the
1829                  *above formula will be equal or less than zero.
1830                  *Skip the channel in this case
1831                  */
1832                 if (flen <= 0) {
1833                         pch->avail = 2;
1834                         spin_unlock(&pch->downl);
1835                         continue;
1836                 }
1837
1838                 /*
1839                  * hdrlen includes the 2-byte PPP protocol field, but the
1840                  * MTU counts only the payload excluding the protocol field.
1841                  * (RFC1661 Section 2)
1842                  */
1843                 mtu = pch->chan->mtu - (hdrlen - 2);
1844                 if (mtu < 4)
1845                         mtu = 4;
1846                 if (flen > mtu)
1847                         flen = mtu;
1848                 if (flen == len)
1849                         bits |= E;
1850                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1851                 if (!frag)
1852                         goto noskb;
1853                 q = skb_put(frag, flen + hdrlen);
1854
1855                 /* make the MP header */
1856                 put_unaligned_be16(PPP_MP, q);
1857                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1858                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1859                         q[3] = ppp->nxseq;
1860                 } else {
1861                         q[2] = bits;
1862                         q[3] = ppp->nxseq >> 16;
1863                         q[4] = ppp->nxseq >> 8;
1864                         q[5] = ppp->nxseq;
1865                 }
1866
1867                 memcpy(q + hdrlen, p, flen);
1868
1869                 /* try to send it down the channel */
1870                 chan = pch->chan;
1871                 if (!skb_queue_empty(&pch->file.xq) ||
1872                         !chan->ops->start_xmit(chan, frag))
1873                         skb_queue_tail(&pch->file.xq, frag);
1874                 pch->had_frag = 1;
1875                 p += flen;
1876                 len -= flen;
1877                 ++ppp->nxseq;
1878                 bits = 0;
1879                 spin_unlock(&pch->downl);
1880         }
1881         ppp->nxchan = i;
1882
1883         return 1;
1884
1885  noskb:
1886         spin_unlock(&pch->downl);
1887         if (ppp->debug & 1)
1888                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1889         ++ppp->dev->stats.tx_errors;
1890         ++ppp->nxseq;
1891         return 1;       /* abandon the frame */
1892 }
1893 #endif /* CONFIG_PPP_MULTILINK */
1894
1895 /* Try to send data out on a channel */
1896 static void __ppp_channel_push(struct channel *pch)
1897 {
1898         struct sk_buff *skb;
1899         struct ppp *ppp;
1900
1901         spin_lock(&pch->downl);
1902         if (pch->chan) {
1903                 while (!skb_queue_empty(&pch->file.xq)) {
1904                         skb = skb_dequeue(&pch->file.xq);
1905                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1906                                 /* put the packet back and try again later */
1907                                 skb_queue_head(&pch->file.xq, skb);
1908                                 break;
1909                         }
1910                 }
1911         } else {
1912                 /* channel got deregistered */
1913                 skb_queue_purge(&pch->file.xq);
1914         }
1915         spin_unlock(&pch->downl);
1916         /* see if there is anything from the attached unit to be sent */
1917         if (skb_queue_empty(&pch->file.xq)) {
1918                 read_lock(&pch->upl);
1919                 ppp = pch->ppp;
1920                 if (ppp)
1921                         ppp_xmit_process(ppp);
1922                 read_unlock(&pch->upl);
1923         }
1924 }
1925
1926 static void ppp_channel_push(struct channel *pch)
1927 {
1928         local_bh_disable();
1929
1930         __ppp_channel_push(pch);
1931
1932         local_bh_enable();
1933 }
1934
1935 /*
1936  * Receive-side routines.
1937  */
1938
1939 struct ppp_mp_skb_parm {
1940         u32             sequence;
1941         u8              BEbits;
1942 };
1943 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1944
1945 static inline void
1946 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1947 {
1948         ppp_recv_lock(ppp);
1949         if (!ppp->closing)
1950                 ppp_receive_frame(ppp, skb, pch);
1951         else
1952                 kfree_skb(skb);
1953         ppp_recv_unlock(ppp);
1954 }
1955
1956 void
1957 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1958 {
1959         struct channel *pch = chan->ppp;
1960         int proto;
1961
1962         if (!pch) {
1963                 kfree_skb(skb);
1964                 return;
1965         }
1966
1967         read_lock_bh(&pch->upl);
1968         if (!pskb_may_pull(skb, 2)) {
1969                 kfree_skb(skb);
1970                 if (pch->ppp) {
1971                         ++pch->ppp->dev->stats.rx_length_errors;
1972                         ppp_receive_error(pch->ppp);
1973                 }
1974                 goto done;
1975         }
1976
1977         proto = PPP_PROTO(skb);
1978         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1979                 /* put it on the channel queue */
1980                 skb_queue_tail(&pch->file.rq, skb);
1981                 /* drop old frames if queue too long */
1982                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1983                        (skb = skb_dequeue(&pch->file.rq)))
1984                         kfree_skb(skb);
1985                 wake_up_interruptible(&pch->file.rwait);
1986         } else {
1987                 ppp_do_recv(pch->ppp, skb, pch);
1988         }
1989
1990 done:
1991         read_unlock_bh(&pch->upl);
1992 }
1993
1994 /* Put a 0-length skb in the receive queue as an error indication */
1995 void
1996 ppp_input_error(struct ppp_channel *chan, int code)
1997 {
1998         struct channel *pch = chan->ppp;
1999         struct sk_buff *skb;
2000
2001         if (!pch)
2002                 return;
2003
2004         read_lock_bh(&pch->upl);
2005         if (pch->ppp) {
2006                 skb = alloc_skb(0, GFP_ATOMIC);
2007                 if (skb) {
2008                         skb->len = 0;           /* probably unnecessary */
2009                         skb->cb[0] = code;
2010                         ppp_do_recv(pch->ppp, skb, pch);
2011                 }
2012         }
2013         read_unlock_bh(&pch->upl);
2014 }
2015
2016 /*
2017  * We come in here to process a received frame.
2018  * The receive side of the ppp unit is locked.
2019  */
2020 static void
2021 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2022 {
2023         /* note: a 0-length skb is used as an error indication */
2024         if (skb->len > 0) {
2025                 skb_checksum_complete_unset(skb);
2026 #ifdef CONFIG_PPP_MULTILINK
2027                 /* XXX do channel-level decompression here */
2028                 if (PPP_PROTO(skb) == PPP_MP)
2029                         ppp_receive_mp_frame(ppp, skb, pch);
2030                 else
2031 #endif /* CONFIG_PPP_MULTILINK */
2032                         ppp_receive_nonmp_frame(ppp, skb);
2033         } else {
2034                 kfree_skb(skb);
2035                 ppp_receive_error(ppp);
2036         }
2037 }
2038
2039 static void
2040 ppp_receive_error(struct ppp *ppp)
2041 {
2042         ++ppp->dev->stats.rx_errors;
2043         if (ppp->vj)
2044                 slhc_toss(ppp->vj);
2045 }
2046
2047 static void
2048 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2049 {
2050         struct sk_buff *ns;
2051         int proto, len, npi;
2052
2053         /*
2054          * Decompress the frame, if compressed.
2055          * Note that some decompressors need to see uncompressed frames
2056          * that come in as well as compressed frames.
2057          */
2058         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2059             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2060                 skb = ppp_decompress_frame(ppp, skb);
2061
2062         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2063                 goto err;
2064
2065         proto = PPP_PROTO(skb);
2066         switch (proto) {
2067         case PPP_VJC_COMP:
2068                 /* decompress VJ compressed packets */
2069                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2070                         goto err;
2071
2072                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2073                         /* copy to a new sk_buff with more tailroom */
2074                         ns = dev_alloc_skb(skb->len + 128);
2075                         if (!ns) {
2076                                 netdev_err(ppp->dev, "PPP: no memory "
2077                                            "(VJ decomp)\n");
2078                                 goto err;
2079                         }
2080                         skb_reserve(ns, 2);
2081                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2082                         consume_skb(skb);
2083                         skb = ns;
2084                 }
2085                 else
2086                         skb->ip_summed = CHECKSUM_NONE;
2087
2088                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2089                 if (len <= 0) {
2090                         netdev_printk(KERN_DEBUG, ppp->dev,
2091                                       "PPP: VJ decompression error\n");
2092                         goto err;
2093                 }
2094                 len += 2;
2095                 if (len > skb->len)
2096                         skb_put(skb, len - skb->len);
2097                 else if (len < skb->len)
2098                         skb_trim(skb, len);
2099                 proto = PPP_IP;
2100                 break;
2101
2102         case PPP_VJC_UNCOMP:
2103                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2104                         goto err;
2105
2106                 /* Until we fix the decompressor need to make sure
2107                  * data portion is linear.
2108                  */
2109                 if (!pskb_may_pull(skb, skb->len))
2110                         goto err;
2111
2112                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2113                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2114                         goto err;
2115                 }
2116                 proto = PPP_IP;
2117                 break;
2118
2119         case PPP_CCP:
2120                 ppp_ccp_peek(ppp, skb, 1);
2121                 break;
2122         }
2123
2124         ++ppp->stats64.rx_packets;
2125         ppp->stats64.rx_bytes += skb->len - 2;
2126
2127         npi = proto_to_npindex(proto);
2128         if (npi < 0) {
2129                 /* control or unknown frame - pass it to pppd */
2130                 skb_queue_tail(&ppp->file.rq, skb);
2131                 /* limit queue length by dropping old frames */
2132                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2133                        (skb = skb_dequeue(&ppp->file.rq)))
2134                         kfree_skb(skb);
2135                 /* wake up any process polling or blocking on read */
2136                 wake_up_interruptible(&ppp->file.rwait);
2137
2138         } else {
2139                 /* network protocol frame - give it to the kernel */
2140
2141 #ifdef CONFIG_PPP_FILTER
2142                 /* check if the packet passes the pass and active filters */
2143                 /* the filter instructions are constructed assuming
2144                    a four-byte PPP header on each packet */
2145                 if (ppp->pass_filter || ppp->active_filter) {
2146                         if (skb_unclone(skb, GFP_ATOMIC))
2147                                 goto err;
2148
2149                         *(u8 *)skb_push(skb, 2) = 0;
2150                         if (ppp->pass_filter &&
2151                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2152                                 if (ppp->debug & 1)
2153                                         netdev_printk(KERN_DEBUG, ppp->dev,
2154                                                       "PPP: inbound frame "
2155                                                       "not passed\n");
2156                                 kfree_skb(skb);
2157                                 return;
2158                         }
2159                         if (!(ppp->active_filter &&
2160                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2161                                 ppp->last_recv = jiffies;
2162                         __skb_pull(skb, 2);
2163                 } else
2164 #endif /* CONFIG_PPP_FILTER */
2165                         ppp->last_recv = jiffies;
2166
2167                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2168                     ppp->npmode[npi] != NPMODE_PASS) {
2169                         kfree_skb(skb);
2170                 } else {
2171                         /* chop off protocol */
2172                         skb_pull_rcsum(skb, 2);
2173                         skb->dev = ppp->dev;
2174                         skb->protocol = htons(npindex_to_ethertype[npi]);
2175                         skb_reset_mac_header(skb);
2176                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2177                                                       dev_net(ppp->dev)));
2178                         netif_rx(skb);
2179                 }
2180         }
2181         return;
2182
2183  err:
2184         kfree_skb(skb);
2185         ppp_receive_error(ppp);
2186 }
2187
2188 static struct sk_buff *
2189 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2190 {
2191         int proto = PPP_PROTO(skb);
2192         struct sk_buff *ns;
2193         int len;
2194
2195         /* Until we fix all the decompressor's need to make sure
2196          * data portion is linear.
2197          */
2198         if (!pskb_may_pull(skb, skb->len))
2199                 goto err;
2200
2201         if (proto == PPP_COMP) {
2202                 int obuff_size;
2203
2204                 switch(ppp->rcomp->compress_proto) {
2205                 case CI_MPPE:
2206                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2207                         break;
2208                 default:
2209                         obuff_size = ppp->mru + PPP_HDRLEN;
2210                         break;
2211                 }
2212
2213                 ns = dev_alloc_skb(obuff_size);
2214                 if (!ns) {
2215                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2216                                    "no memory\n");
2217                         goto err;
2218                 }
2219                 /* the decompressor still expects the A/C bytes in the hdr */
2220                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2221                                 skb->len + 2, ns->data, obuff_size);
2222                 if (len < 0) {
2223                         /* Pass the compressed frame to pppd as an
2224                            error indication. */
2225                         if (len == DECOMP_FATALERROR)
2226                                 ppp->rstate |= SC_DC_FERROR;
2227                         kfree_skb(ns);
2228                         goto err;
2229                 }
2230
2231                 consume_skb(skb);
2232                 skb = ns;
2233                 skb_put(skb, len);
2234                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2235
2236         } else {
2237                 /* Uncompressed frame - pass to decompressor so it
2238                    can update its dictionary if necessary. */
2239                 if (ppp->rcomp->incomp)
2240                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2241                                            skb->len + 2);
2242         }
2243
2244         return skb;
2245
2246  err:
2247         ppp->rstate |= SC_DC_ERROR;
2248         ppp_receive_error(ppp);
2249         return skb;
2250 }
2251
2252 #ifdef CONFIG_PPP_MULTILINK
2253 /*
2254  * Receive a multilink frame.
2255  * We put it on the reconstruction queue and then pull off
2256  * as many completed frames as we can.
2257  */
2258 static void
2259 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2260 {
2261         u32 mask, seq;
2262         struct channel *ch;
2263         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2264
2265         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2266                 goto err;               /* no good, throw it away */
2267
2268         /* Decode sequence number and begin/end bits */
2269         if (ppp->flags & SC_MP_SHORTSEQ) {
2270                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2271                 mask = 0xfff;
2272         } else {
2273                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2274                 mask = 0xffffff;
2275         }
2276         PPP_MP_CB(skb)->BEbits = skb->data[2];
2277         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2278
2279         /*
2280          * Do protocol ID decompression on the first fragment of each packet.
2281          */
2282         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2283                 *(u8 *)skb_push(skb, 1) = 0;
2284
2285         /*
2286          * Expand sequence number to 32 bits, making it as close
2287          * as possible to ppp->minseq.
2288          */
2289         seq |= ppp->minseq & ~mask;
2290         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2291                 seq += mask + 1;
2292         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2293                 seq -= mask + 1;        /* should never happen */
2294         PPP_MP_CB(skb)->sequence = seq;
2295         pch->lastseq = seq;
2296
2297         /*
2298          * If this packet comes before the next one we were expecting,
2299          * drop it.
2300          */
2301         if (seq_before(seq, ppp->nextseq)) {
2302                 kfree_skb(skb);
2303                 ++ppp->dev->stats.rx_dropped;
2304                 ppp_receive_error(ppp);
2305                 return;
2306         }
2307
2308         /*
2309          * Reevaluate minseq, the minimum over all channels of the
2310          * last sequence number received on each channel.  Because of
2311          * the increasing sequence number rule, we know that any fragment
2312          * before `minseq' which hasn't arrived is never going to arrive.
2313          * The list of channels can't change because we have the receive
2314          * side of the ppp unit locked.
2315          */
2316         list_for_each_entry(ch, &ppp->channels, clist) {
2317                 if (seq_before(ch->lastseq, seq))
2318                         seq = ch->lastseq;
2319         }
2320         if (seq_before(ppp->minseq, seq))
2321                 ppp->minseq = seq;
2322
2323         /* Put the fragment on the reconstruction queue */
2324         ppp_mp_insert(ppp, skb);
2325
2326         /* If the queue is getting long, don't wait any longer for packets
2327            before the start of the queue. */
2328         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2329                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2330                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2331                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2332         }
2333
2334         /* Pull completed packets off the queue and receive them. */
2335         while ((skb = ppp_mp_reconstruct(ppp))) {
2336                 if (pskb_may_pull(skb, 2))
2337                         ppp_receive_nonmp_frame(ppp, skb);
2338                 else {
2339                         ++ppp->dev->stats.rx_length_errors;
2340                         kfree_skb(skb);
2341                         ppp_receive_error(ppp);
2342                 }
2343         }
2344
2345         return;
2346
2347  err:
2348         kfree_skb(skb);
2349         ppp_receive_error(ppp);
2350 }
2351
2352 /*
2353  * Insert a fragment on the MP reconstruction queue.
2354  * The queue is ordered by increasing sequence number.
2355  */
2356 static void
2357 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2358 {
2359         struct sk_buff *p;
2360         struct sk_buff_head *list = &ppp->mrq;
2361         u32 seq = PPP_MP_CB(skb)->sequence;
2362
2363         /* N.B. we don't need to lock the list lock because we have the
2364            ppp unit receive-side lock. */
2365         skb_queue_walk(list, p) {
2366                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2367                         break;
2368         }
2369         __skb_queue_before(list, p, skb);
2370 }
2371
2372 /*
2373  * Reconstruct a packet from the MP fragment queue.
2374  * We go through increasing sequence numbers until we find a
2375  * complete packet, or we get to the sequence number for a fragment
2376  * which hasn't arrived but might still do so.
2377  */
2378 static struct sk_buff *
2379 ppp_mp_reconstruct(struct ppp *ppp)
2380 {
2381         u32 seq = ppp->nextseq;
2382         u32 minseq = ppp->minseq;
2383         struct sk_buff_head *list = &ppp->mrq;
2384         struct sk_buff *p, *tmp;
2385         struct sk_buff *head, *tail;
2386         struct sk_buff *skb = NULL;
2387         int lost = 0, len = 0;
2388
2389         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2390                 return NULL;
2391         head = list->next;
2392         tail = NULL;
2393         skb_queue_walk_safe(list, p, tmp) {
2394         again:
2395                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2396                         /* this can't happen, anyway ignore the skb */
2397                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2398                                    "seq %u < %u\n",
2399                                    PPP_MP_CB(p)->sequence, seq);
2400                         __skb_unlink(p, list);
2401                         kfree_skb(p);
2402                         continue;
2403                 }
2404                 if (PPP_MP_CB(p)->sequence != seq) {
2405                         u32 oldseq;
2406                         /* Fragment `seq' is missing.  If it is after
2407                            minseq, it might arrive later, so stop here. */
2408                         if (seq_after(seq, minseq))
2409                                 break;
2410                         /* Fragment `seq' is lost, keep going. */
2411                         lost = 1;
2412                         oldseq = seq;
2413                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2414                                 minseq + 1: PPP_MP_CB(p)->sequence;
2415
2416                         if (ppp->debug & 1)
2417                                 netdev_printk(KERN_DEBUG, ppp->dev,
2418                                               "lost frag %u..%u\n",
2419                                               oldseq, seq-1);
2420
2421                         goto again;
2422                 }
2423
2424                 /*
2425                  * At this point we know that all the fragments from
2426                  * ppp->nextseq to seq are either present or lost.
2427                  * Also, there are no complete packets in the queue
2428                  * that have no missing fragments and end before this
2429                  * fragment.
2430                  */
2431
2432                 /* B bit set indicates this fragment starts a packet */
2433                 if (PPP_MP_CB(p)->BEbits & B) {
2434                         head = p;
2435                         lost = 0;
2436                         len = 0;
2437                 }
2438
2439                 len += p->len;
2440
2441                 /* Got a complete packet yet? */
2442                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2443                     (PPP_MP_CB(head)->BEbits & B)) {
2444                         if (len > ppp->mrru + 2) {
2445                                 ++ppp->dev->stats.rx_length_errors;
2446                                 netdev_printk(KERN_DEBUG, ppp->dev,
2447                                               "PPP: reconstructed packet"
2448                                               " is too long (%d)\n", len);
2449                         } else {
2450                                 tail = p;
2451                                 break;
2452                         }
2453                         ppp->nextseq = seq + 1;
2454                 }
2455
2456                 /*
2457                  * If this is the ending fragment of a packet,
2458                  * and we haven't found a complete valid packet yet,
2459                  * we can discard up to and including this fragment.
2460                  */
2461                 if (PPP_MP_CB(p)->BEbits & E) {
2462                         struct sk_buff *tmp2;
2463
2464                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2465                                 if (ppp->debug & 1)
2466                                         netdev_printk(KERN_DEBUG, ppp->dev,
2467                                                       "discarding frag %u\n",
2468                                                       PPP_MP_CB(p)->sequence);
2469                                 __skb_unlink(p, list);
2470                                 kfree_skb(p);
2471                         }
2472                         head = skb_peek(list);
2473                         if (!head)
2474                                 break;
2475                 }
2476                 ++seq;
2477         }
2478
2479         /* If we have a complete packet, copy it all into one skb. */
2480         if (tail != NULL) {
2481                 /* If we have discarded any fragments,
2482                    signal a receive error. */
2483                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2484                         skb_queue_walk_safe(list, p, tmp) {
2485                                 if (p == head)
2486                                         break;
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
2495                         if (ppp->debug & 1)
2496                                 netdev_printk(KERN_DEBUG, ppp->dev,
2497                                               "  missed pkts %u..%u\n",
2498                                               ppp->nextseq,
2499                                               PPP_MP_CB(head)->sequence-1);
2500                         ++ppp->dev->stats.rx_dropped;
2501                         ppp_receive_error(ppp);
2502                 }
2503
2504                 skb = head;
2505                 if (head != tail) {
2506                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2507                         p = skb_queue_next(list, head);
2508                         __skb_unlink(skb, list);
2509                         skb_queue_walk_from_safe(list, p, tmp) {
2510                                 __skb_unlink(p, list);
2511                                 *fragpp = p;
2512                                 p->next = NULL;
2513                                 fragpp = &p->next;
2514
2515                                 skb->len += p->len;
2516                                 skb->data_len += p->len;
2517                                 skb->truesize += p->truesize;
2518
2519                                 if (p == tail)
2520                                         break;
2521                         }
2522                 } else {
2523                         __skb_unlink(skb, list);
2524                 }
2525
2526                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2527         }
2528
2529         return skb;
2530 }
2531 #endif /* CONFIG_PPP_MULTILINK */
2532
2533 /*
2534  * Channel interface.
2535  */
2536
2537 /* Create a new, unattached ppp channel. */
2538 int ppp_register_channel(struct ppp_channel *chan)
2539 {
2540         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2541 }
2542
2543 /* Create a new, unattached ppp channel for specified net. */
2544 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2545 {
2546         struct channel *pch;
2547         struct ppp_net *pn;
2548
2549         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2550         if (!pch)
2551                 return -ENOMEM;
2552
2553         pn = ppp_pernet(net);
2554
2555         pch->ppp = NULL;
2556         pch->chan = chan;
2557         pch->chan_net = get_net(net);
2558         chan->ppp = pch;
2559         init_ppp_file(&pch->file, CHANNEL);
2560         pch->file.hdrlen = chan->hdrlen;
2561 #ifdef CONFIG_PPP_MULTILINK
2562         pch->lastseq = -1;
2563 #endif /* CONFIG_PPP_MULTILINK */
2564         init_rwsem(&pch->chan_sem);
2565         spin_lock_init(&pch->downl);
2566         rwlock_init(&pch->upl);
2567
2568         spin_lock_bh(&pn->all_channels_lock);
2569         pch->file.index = ++pn->last_channel_index;
2570         list_add(&pch->list, &pn->new_channels);
2571         atomic_inc(&channel_count);
2572         spin_unlock_bh(&pn->all_channels_lock);
2573
2574         return 0;
2575 }
2576
2577 /*
2578  * Return the index of a channel.
2579  */
2580 int ppp_channel_index(struct ppp_channel *chan)
2581 {
2582         struct channel *pch = chan->ppp;
2583
2584         if (pch)
2585                 return pch->file.index;
2586         return -1;
2587 }
2588
2589 /*
2590  * Return the PPP unit number to which a channel is connected.
2591  */
2592 int ppp_unit_number(struct ppp_channel *chan)
2593 {
2594         struct channel *pch = chan->ppp;
2595         int unit = -1;
2596
2597         if (pch) {
2598                 read_lock_bh(&pch->upl);
2599                 if (pch->ppp)
2600                         unit = pch->ppp->file.index;
2601                 read_unlock_bh(&pch->upl);
2602         }
2603         return unit;
2604 }
2605
2606 /*
2607  * Return the PPP device interface name of a channel.
2608  */
2609 char *ppp_dev_name(struct ppp_channel *chan)
2610 {
2611         struct channel *pch = chan->ppp;
2612         char *name = NULL;
2613
2614         if (pch) {
2615                 read_lock_bh(&pch->upl);
2616                 if (pch->ppp && pch->ppp->dev)
2617                         name = pch->ppp->dev->name;
2618                 read_unlock_bh(&pch->upl);
2619         }
2620         return name;
2621 }
2622
2623
2624 /*
2625  * Disconnect a channel from the generic layer.
2626  * This must be called in process context.
2627  */
2628 void
2629 ppp_unregister_channel(struct ppp_channel *chan)
2630 {
2631         struct channel *pch = chan->ppp;
2632         struct ppp_net *pn;
2633
2634         if (!pch)
2635                 return;         /* should never happen */
2636
2637         chan->ppp = NULL;
2638
2639         /*
2640          * This ensures that we have returned from any calls into the
2641          * the channel's start_xmit or ioctl routine before we proceed.
2642          */
2643         down_write(&pch->chan_sem);
2644         spin_lock_bh(&pch->downl);
2645         pch->chan = NULL;
2646         spin_unlock_bh(&pch->downl);
2647         up_write(&pch->chan_sem);
2648         ppp_disconnect_channel(pch);
2649
2650         pn = ppp_pernet(pch->chan_net);
2651         spin_lock_bh(&pn->all_channels_lock);
2652         list_del(&pch->list);
2653         spin_unlock_bh(&pn->all_channels_lock);
2654
2655         pch->file.dead = 1;
2656         wake_up_interruptible(&pch->file.rwait);
2657         if (atomic_dec_and_test(&pch->file.refcnt))
2658                 ppp_destroy_channel(pch);
2659 }
2660
2661 /*
2662  * Callback from a channel when it can accept more to transmit.
2663  * This should be called at BH/softirq level, not interrupt level.
2664  */
2665 void
2666 ppp_output_wakeup(struct ppp_channel *chan)
2667 {
2668         struct channel *pch = chan->ppp;
2669
2670         if (!pch)
2671                 return;
2672         ppp_channel_push(pch);
2673 }
2674
2675 /*
2676  * Compression control.
2677  */
2678
2679 /* Process the PPPIOCSCOMPRESS ioctl. */
2680 static int
2681 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2682 {
2683         int err;
2684         struct compressor *cp, *ocomp;
2685         struct ppp_option_data data;
2686         void *state, *ostate;
2687         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2688
2689         err = -EFAULT;
2690         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2691                 goto out;
2692         if (data.length > CCP_MAX_OPTION_LENGTH)
2693                 goto out;
2694         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2695                 goto out;
2696
2697         err = -EINVAL;
2698         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2699                 goto out;
2700
2701         cp = try_then_request_module(
2702                 find_compressor(ccp_option[0]),
2703                 "ppp-compress-%d", ccp_option[0]);
2704         if (!cp)
2705                 goto out;
2706
2707         err = -ENOBUFS;
2708         if (data.transmit) {
2709                 state = cp->comp_alloc(ccp_option, data.length);
2710                 if (state) {
2711                         ppp_xmit_lock(ppp);
2712                         ppp->xstate &= ~SC_COMP_RUN;
2713                         ocomp = ppp->xcomp;
2714                         ostate = ppp->xc_state;
2715                         ppp->xcomp = cp;
2716                         ppp->xc_state = state;
2717                         ppp_xmit_unlock(ppp);
2718                         if (ostate) {
2719                                 ocomp->comp_free(ostate);
2720                                 module_put(ocomp->owner);
2721                         }
2722                         err = 0;
2723                 } else
2724                         module_put(cp->owner);
2725
2726         } else {
2727                 state = cp->decomp_alloc(ccp_option, data.length);
2728                 if (state) {
2729                         ppp_recv_lock(ppp);
2730                         ppp->rstate &= ~SC_DECOMP_RUN;
2731                         ocomp = ppp->rcomp;
2732                         ostate = ppp->rc_state;
2733                         ppp->rcomp = cp;
2734                         ppp->rc_state = state;
2735                         ppp_recv_unlock(ppp);
2736                         if (ostate) {
2737                                 ocomp->decomp_free(ostate);
2738                                 module_put(ocomp->owner);
2739                         }
2740                         err = 0;
2741                 } else
2742                         module_put(cp->owner);
2743         }
2744
2745  out:
2746         return err;
2747 }
2748
2749 /*
2750  * Look at a CCP packet and update our state accordingly.
2751  * We assume the caller has the xmit or recv path locked.
2752  */
2753 static void
2754 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2755 {
2756         unsigned char *dp;
2757         int len;
2758
2759         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2760                 return; /* no header */
2761         dp = skb->data + 2;
2762
2763         switch (CCP_CODE(dp)) {
2764         case CCP_CONFREQ:
2765
2766                 /* A ConfReq starts negotiation of compression
2767                  * in one direction of transmission,
2768                  * and hence brings it down...but which way?
2769                  *
2770                  * Remember:
2771                  * A ConfReq indicates what the sender would like to receive
2772                  */
2773                 if(inbound)
2774                         /* He is proposing what I should send */
2775                         ppp->xstate &= ~SC_COMP_RUN;
2776                 else
2777                         /* I am proposing to what he should send */
2778                         ppp->rstate &= ~SC_DECOMP_RUN;
2779
2780                 break;
2781
2782         case CCP_TERMREQ:
2783         case CCP_TERMACK:
2784                 /*
2785                  * CCP is going down, both directions of transmission
2786                  */
2787                 ppp->rstate &= ~SC_DECOMP_RUN;
2788                 ppp->xstate &= ~SC_COMP_RUN;
2789                 break;
2790
2791         case CCP_CONFACK:
2792                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2793                         break;
2794                 len = CCP_LENGTH(dp);
2795                 if (!pskb_may_pull(skb, len + 2))
2796                         return;         /* too short */
2797                 dp += CCP_HDRLEN;
2798                 len -= CCP_HDRLEN;
2799                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2800                         break;
2801                 if (inbound) {
2802                         /* we will start receiving compressed packets */
2803                         if (!ppp->rc_state)
2804                                 break;
2805                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2806                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2807                                 ppp->rstate |= SC_DECOMP_RUN;
2808                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2809                         }
2810                 } else {
2811                         /* we will soon start sending compressed packets */
2812                         if (!ppp->xc_state)
2813                                 break;
2814                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2815                                         ppp->file.index, 0, ppp->debug))
2816                                 ppp->xstate |= SC_COMP_RUN;
2817                 }
2818                 break;
2819
2820         case CCP_RESETACK:
2821                 /* reset the [de]compressor */
2822                 if ((ppp->flags & SC_CCP_UP) == 0)
2823                         break;
2824                 if (inbound) {
2825                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2826                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2827                                 ppp->rstate &= ~SC_DC_ERROR;
2828                         }
2829                 } else {
2830                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2831                                 ppp->xcomp->comp_reset(ppp->xc_state);
2832                 }
2833                 break;
2834         }
2835 }
2836
2837 /* Free up compression resources. */
2838 static void
2839 ppp_ccp_closed(struct ppp *ppp)
2840 {
2841         void *xstate, *rstate;
2842         struct compressor *xcomp, *rcomp;
2843
2844         ppp_lock(ppp);
2845         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2846         ppp->xstate = 0;
2847         xcomp = ppp->xcomp;
2848         xstate = ppp->xc_state;
2849         ppp->xc_state = NULL;
2850         ppp->rstate = 0;
2851         rcomp = ppp->rcomp;
2852         rstate = ppp->rc_state;
2853         ppp->rc_state = NULL;
2854         ppp_unlock(ppp);
2855
2856         if (xstate) {
2857                 xcomp->comp_free(xstate);
2858                 module_put(xcomp->owner);
2859         }
2860         if (rstate) {
2861                 rcomp->decomp_free(rstate);
2862                 module_put(rcomp->owner);
2863         }
2864 }
2865
2866 /* List of compressors. */
2867 static LIST_HEAD(compressor_list);
2868 static DEFINE_SPINLOCK(compressor_list_lock);
2869
2870 struct compressor_entry {
2871         struct list_head list;
2872         struct compressor *comp;
2873 };
2874
2875 static struct compressor_entry *
2876 find_comp_entry(int proto)
2877 {
2878         struct compressor_entry *ce;
2879
2880         list_for_each_entry(ce, &compressor_list, list) {
2881                 if (ce->comp->compress_proto == proto)
2882                         return ce;
2883         }
2884         return NULL;
2885 }
2886
2887 /* Register a compressor */
2888 int
2889 ppp_register_compressor(struct compressor *cp)
2890 {
2891         struct compressor_entry *ce;
2892         int ret;
2893         spin_lock(&compressor_list_lock);
2894         ret = -EEXIST;
2895         if (find_comp_entry(cp->compress_proto))
2896                 goto out;
2897         ret = -ENOMEM;
2898         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2899         if (!ce)
2900                 goto out;
2901         ret = 0;
2902         ce->comp = cp;
2903         list_add(&ce->list, &compressor_list);
2904  out:
2905         spin_unlock(&compressor_list_lock);
2906         return ret;
2907 }
2908
2909 /* Unregister a compressor */
2910 void
2911 ppp_unregister_compressor(struct compressor *cp)
2912 {
2913         struct compressor_entry *ce;
2914
2915         spin_lock(&compressor_list_lock);
2916         ce = find_comp_entry(cp->compress_proto);
2917         if (ce && ce->comp == cp) {
2918                 list_del(&ce->list);
2919                 kfree(ce);
2920         }
2921         spin_unlock(&compressor_list_lock);
2922 }
2923
2924 /* Find a compressor. */
2925 static struct compressor *
2926 find_compressor(int type)
2927 {
2928         struct compressor_entry *ce;
2929         struct compressor *cp = NULL;
2930
2931         spin_lock(&compressor_list_lock);
2932         ce = find_comp_entry(type);
2933         if (ce) {
2934                 cp = ce->comp;
2935                 if (!try_module_get(cp->owner))
2936                         cp = NULL;
2937         }
2938         spin_unlock(&compressor_list_lock);
2939         return cp;
2940 }
2941
2942 /*
2943  * Miscelleneous stuff.
2944  */
2945
2946 static void
2947 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2948 {
2949         struct slcompress *vj = ppp->vj;
2950
2951         memset(st, 0, sizeof(*st));
2952         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2953         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2954         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2955         st->p.ppp_opackets = ppp->stats64.tx_packets;
2956         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2957         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2958         if (!vj)
2959                 return;
2960         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2961         st->vj.vjs_compressed = vj->sls_o_compressed;
2962         st->vj.vjs_searches = vj->sls_o_searches;
2963         st->vj.vjs_misses = vj->sls_o_misses;
2964         st->vj.vjs_errorin = vj->sls_i_error;
2965         st->vj.vjs_tossed = vj->sls_i_tossed;
2966         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2967         st->vj.vjs_compressedin = vj->sls_i_compressed;
2968 }
2969
2970 /*
2971  * Stuff for handling the lists of ppp units and channels
2972  * and for initialization.
2973  */
2974
2975 /*
2976  * Create a new ppp interface unit.  Fails if it can't allocate memory
2977  * or if there is already a unit with the requested number.
2978  * unit == -1 means allocate a new number.
2979  */
2980 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
2981 {
2982         struct ppp_config conf = {
2983                 .file = file,
2984                 .unit = *unit,
2985                 .ifname_is_set = false,
2986         };
2987         struct net_device *dev;
2988         struct ppp *ppp;
2989         int err;
2990
2991         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
2992         if (!dev) {
2993                 err = -ENOMEM;
2994                 goto err;
2995         }
2996         dev_net_set(dev, net);
2997         dev->rtnl_link_ops = &ppp_link_ops;
2998
2999         rtnl_lock();
3000
3001         err = ppp_dev_configure(net, dev, &conf);
3002         if (err < 0)
3003                 goto err_dev;
3004         ppp = netdev_priv(dev);
3005         *unit = ppp->file.index;
3006
3007         rtnl_unlock();
3008
3009         return 0;
3010
3011 err_dev:
3012         rtnl_unlock();
3013         free_netdev(dev);
3014 err:
3015         return err;
3016 }
3017
3018 /*
3019  * Initialize a ppp_file structure.
3020  */
3021 static void
3022 init_ppp_file(struct ppp_file *pf, int kind)
3023 {
3024         pf->kind = kind;
3025         skb_queue_head_init(&pf->xq);
3026         skb_queue_head_init(&pf->rq);
3027         atomic_set(&pf->refcnt, 1);
3028         init_waitqueue_head(&pf->rwait);
3029 }
3030
3031 /*
3032  * Free the memory used by a ppp unit.  This is only called once
3033  * there are no channels connected to the unit and no file structs
3034  * that reference the unit.
3035  */
3036 static void ppp_destroy_interface(struct ppp *ppp)
3037 {
3038         atomic_dec(&ppp_unit_count);
3039
3040         if (!ppp->file.dead || ppp->n_channels) {
3041                 /* "can't happen" */
3042                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3043                            "but dead=%d n_channels=%d !\n",
3044                            ppp, ppp->file.dead, ppp->n_channels);
3045                 return;
3046         }
3047
3048         ppp_ccp_closed(ppp);
3049         if (ppp->vj) {
3050                 slhc_free(ppp->vj);
3051                 ppp->vj = NULL;
3052         }
3053         skb_queue_purge(&ppp->file.xq);
3054         skb_queue_purge(&ppp->file.rq);
3055 #ifdef CONFIG_PPP_MULTILINK
3056         skb_queue_purge(&ppp->mrq);
3057 #endif /* CONFIG_PPP_MULTILINK */
3058 #ifdef CONFIG_PPP_FILTER
3059         if (ppp->pass_filter) {
3060                 bpf_prog_destroy(ppp->pass_filter);
3061                 ppp->pass_filter = NULL;
3062         }
3063
3064         if (ppp->active_filter) {
3065                 bpf_prog_destroy(ppp->active_filter);
3066                 ppp->active_filter = NULL;
3067         }
3068 #endif /* CONFIG_PPP_FILTER */
3069
3070         kfree_skb(ppp->xmit_pending);
3071         free_percpu(ppp->xmit_recursion);
3072
3073         free_netdev(ppp->dev);
3074 }
3075
3076 /*
3077  * Locate an existing ppp unit.
3078  * The caller should have locked the all_ppp_mutex.
3079  */
3080 static struct ppp *
3081 ppp_find_unit(struct ppp_net *pn, int unit)
3082 {
3083         return unit_find(&pn->units_idr, unit);
3084 }
3085
3086 /*
3087  * Locate an existing ppp channel.
3088  * The caller should have locked the all_channels_lock.
3089  * First we look in the new_channels list, then in the
3090  * all_channels list.  If found in the new_channels list,
3091  * we move it to the all_channels list.  This is for speed
3092  * when we have a lot of channels in use.
3093  */
3094 static struct channel *
3095 ppp_find_channel(struct ppp_net *pn, int unit)
3096 {
3097         struct channel *pch;
3098
3099         list_for_each_entry(pch, &pn->new_channels, list) {
3100                 if (pch->file.index == unit) {
3101                         list_move(&pch->list, &pn->all_channels);
3102                         return pch;
3103                 }
3104         }
3105
3106         list_for_each_entry(pch, &pn->all_channels, list) {
3107                 if (pch->file.index == unit)
3108                         return pch;
3109         }
3110
3111         return NULL;
3112 }
3113
3114 /*
3115  * Connect a PPP channel to a PPP interface unit.
3116  */
3117 static int
3118 ppp_connect_channel(struct channel *pch, int unit)
3119 {
3120         struct ppp *ppp;
3121         struct ppp_net *pn;
3122         int ret = -ENXIO;
3123         int hdrlen;
3124
3125         pn = ppp_pernet(pch->chan_net);
3126
3127         mutex_lock(&pn->all_ppp_mutex);
3128         ppp = ppp_find_unit(pn, unit);
3129         if (!ppp)
3130                 goto out;
3131         write_lock_bh(&pch->upl);
3132         ret = -EINVAL;
3133         if (pch->ppp)
3134                 goto outl;
3135
3136         ppp_lock(ppp);
3137         if (pch->file.hdrlen > ppp->file.hdrlen)
3138                 ppp->file.hdrlen = pch->file.hdrlen;
3139         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3140         if (hdrlen > ppp->dev->hard_header_len)
3141                 ppp->dev->hard_header_len = hdrlen;
3142         list_add_tail(&pch->clist, &ppp->channels);
3143         ++ppp->n_channels;
3144         pch->ppp = ppp;
3145         atomic_inc(&ppp->file.refcnt);
3146         ppp_unlock(ppp);
3147         ret = 0;
3148
3149  outl:
3150         write_unlock_bh(&pch->upl);
3151  out:
3152         mutex_unlock(&pn->all_ppp_mutex);
3153         return ret;
3154 }
3155
3156 /*
3157  * Disconnect a channel from its ppp unit.
3158  */
3159 static int
3160 ppp_disconnect_channel(struct channel *pch)
3161 {
3162         struct ppp *ppp;
3163         int err = -EINVAL;
3164
3165         write_lock_bh(&pch->upl);
3166         ppp = pch->ppp;
3167         pch->ppp = NULL;
3168         write_unlock_bh(&pch->upl);
3169         if (ppp) {
3170                 /* remove it from the ppp unit's list */
3171                 ppp_lock(ppp);
3172                 list_del(&pch->clist);
3173                 if (--ppp->n_channels == 0)
3174                         wake_up_interruptible(&ppp->file.rwait);
3175                 ppp_unlock(ppp);
3176                 if (atomic_dec_and_test(&ppp->file.refcnt))
3177                         ppp_destroy_interface(ppp);
3178                 err = 0;
3179         }
3180         return err;
3181 }
3182
3183 /*
3184  * Free up the resources used by a ppp channel.
3185  */
3186 static void ppp_destroy_channel(struct channel *pch)
3187 {
3188         put_net(pch->chan_net);
3189         pch->chan_net = NULL;
3190
3191         atomic_dec(&channel_count);
3192
3193         if (!pch->file.dead) {
3194                 /* "can't happen" */
3195                 pr_err("ppp: destroying undead channel %p !\n", pch);
3196                 return;
3197         }
3198         skb_queue_purge(&pch->file.xq);
3199         skb_queue_purge(&pch->file.rq);
3200         kfree(pch);
3201 }
3202
3203 static void __exit ppp_cleanup(void)
3204 {
3205         /* should never happen */
3206         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3207                 pr_err("PPP: removing module but units remain!\n");
3208         rtnl_link_unregister(&ppp_link_ops);
3209         unregister_chrdev(PPP_MAJOR, "ppp");
3210         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3211         class_destroy(ppp_class);
3212         unregister_pernet_device(&ppp_net_ops);
3213 }
3214
3215 /*
3216  * Units handling. Caller must protect concurrent access
3217  * by holding all_ppp_mutex
3218  */
3219
3220 /* associate pointer with specified number */
3221 static int unit_set(struct idr *p, void *ptr, int n)
3222 {
3223         int unit;
3224
3225         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3226         if (unit == -ENOSPC)
3227                 unit = -EINVAL;
3228         return unit;
3229 }
3230
3231 /* get new free unit number and associate pointer with it */
3232 static int unit_get(struct idr *p, void *ptr)
3233 {
3234         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3235 }
3236
3237 /* put unit number back to a pool */
3238 static void unit_put(struct idr *p, int n)
3239 {
3240         idr_remove(p, n);
3241 }
3242
3243 /* get pointer associated with the number */
3244 static void *unit_find(struct idr *p, int n)
3245 {
3246         return idr_find(p, n);
3247 }
3248
3249 /* Module/initialization stuff */
3250
3251 module_init(ppp_init);
3252 module_exit(ppp_cleanup);
3253
3254 EXPORT_SYMBOL(ppp_register_net_channel);
3255 EXPORT_SYMBOL(ppp_register_channel);
3256 EXPORT_SYMBOL(ppp_unregister_channel);
3257 EXPORT_SYMBOL(ppp_channel_index);
3258 EXPORT_SYMBOL(ppp_unit_number);
3259 EXPORT_SYMBOL(ppp_dev_name);
3260 EXPORT_SYMBOL(ppp_input);
3261 EXPORT_SYMBOL(ppp_input_error);
3262 EXPORT_SYMBOL(ppp_output_wakeup);
3263 EXPORT_SYMBOL(ppp_register_compressor);
3264 EXPORT_SYMBOL(ppp_unregister_compressor);
3265 MODULE_LICENSE("GPL");
3266 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3267 MODULE_ALIAS_RTNL_LINK("ppp");
3268 MODULE_ALIAS("devname:ppp");