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 #include <linux/refcount.h>
  55
  56 #include <linux/nsproxy.h>
  57 #include <net/net_namespace.h>
  58 #include <net/netns/generic.h>
  59
  60 #define PPP_VERSION     "2.4.2"
  61
  62 /*
  63  * Network protocols we support.
  64  */
  65 #define NP_IP   0               /* Internet Protocol V4 */
  66 #define NP_IPV6 1               /* Internet Protocol V6 */
  67 #define NP_IPX  2               /* IPX protocol */
  68 #define NP_AT   3               /* Appletalk protocol */
  69 #define NP_MPLS_UC 4            /* MPLS unicast */
  70 #define NP_MPLS_MC 5            /* MPLS multicast */
  71 #define NUM_NP  6               /* Number of NPs. */
  72
  73 #define MPHDRLEN        6       /* multilink protocol header length */
  74 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  75
  76 #define PPP_PROTO_LEN   2
  77
  78 /*
  79  * An instance of /dev/ppp can be associated with either a ppp
  80  * interface unit or a ppp channel.  In both cases, file->private_data
  81  * points to one of these.
  82  */
  83 struct ppp_file {
  84         enum {
  85                 INTERFACE=1, CHANNEL
  86         }               kind;
  87         struct sk_buff_head xq;         /* pppd transmit queue */
  88         struct sk_buff_head rq;         /* receive queue for pppd */
  89         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  90         refcount_t      refcnt;         /* # refs (incl /dev/ppp attached) */
  91         int             hdrlen;         /* space to leave for headers */
  92         int             index;          /* interface unit / channel number */
  93         int             dead;           /* unit/channel has been shut down */
  94 };
  95
  96 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  97
  98 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  99 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
 100
 101 /*
 102  * Data structure to hold primary network stats for which
 103  * we want to use 64 bit storage.  Other network stats
 104  * are stored in dev->stats of the ppp strucute.
 105  */
 106 struct ppp_link_stats {
 107         u64 rx_packets;
 108         u64 tx_packets;
 109         u64 rx_bytes;
 110         u64 tx_bytes;
 111 };
 112
 113 /*
 114  * Data structure describing one ppp unit.
 115  * A ppp unit corresponds to a ppp network interface device
 116  * and represents a multilink bundle.
 117  * It can have 0 or more ppp channels connected to it.
 118  */
 119 struct ppp {
 120         struct ppp_file file;           /* stuff for read/write/poll 0 */
 121         struct file     *owner;         /* file that owns this unit 48 */
 122         struct list_head channels;      /* list of attached channels 4c */
 123         int             n_channels;     /* how many channels are attached 54 */
 124         spinlock_t      rlock;          /* lock for receive side 58 */
 125         spinlock_t      wlock;          /* lock for transmit side 5c */
 126         int __percpu    *xmit_recursion; /* xmit recursion detect */
 127         int             mru;            /* max receive unit 60 */
 128         unsigned int    flags;          /* control bits 64 */
 129         unsigned int    xstate;         /* transmit state bits 68 */
 130         unsigned int    rstate;         /* receive state bits 6c */
 131         int             debug;          /* debug flags 70 */
 132         struct slcompress *vj;          /* state for VJ header compression */
 133         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 134         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 135         struct compressor *xcomp;       /* transmit packet compressor 8c */
 136         void            *xc_state;      /* its internal state 90 */
 137         struct compressor *rcomp;       /* receive decompressor 94 */
 138         void            *rc_state;      /* its internal state 98 */
 139         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 140         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 141         struct net_device *dev;         /* network interface device a4 */
 142         int             closing;        /* is device closing down? a8 */
 143 #ifdef CONFIG_PPP_MULTILINK
 144         int             nxchan;         /* next channel to send something on */
 145         u32             nxseq;          /* next sequence number to send */
 146         int             mrru;           /* MP: max reconst. receive unit */
 147         u32             nextseq;        /* MP: seq no of next packet */
 148         u32             minseq;         /* MP: min of most recent seqnos */
 149         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 150 #endif /* CONFIG_PPP_MULTILINK */
 151 #ifdef CONFIG_PPP_FILTER
 152         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 153         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 154 #endif /* CONFIG_PPP_FILTER */
 155         struct net      *ppp_net;       /* the net we belong to */
 156         struct ppp_link_stats stats64;  /* 64 bit network stats */
 157 };
 158
 159 /*
 160  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 161  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 162  * SC_MUST_COMP
 163  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 164  * Bits in xstate: SC_COMP_RUN
 165  */
 166 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 167                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 168                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 169
 170 /*
 171  * Private data structure for each channel.
 172  * This includes the data structure used for multilink.
 173  */
 174 struct channel {
 175         struct ppp_file file;           /* stuff for read/write/poll */
 176         struct list_head list;          /* link in all/new_channels list */
 177         struct ppp_channel *chan;       /* public channel data structure */
 178         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 179         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 180         struct ppp      *ppp;           /* ppp unit we're connected to */
 181         struct net      *chan_net;      /* the net channel belongs to */
 182         struct list_head clist;         /* link in list of channels per unit */
 183         rwlock_t        upl;            /* protects `ppp' */
 184 #ifdef CONFIG_PPP_MULTILINK
 185         u8              avail;          /* flag used in multilink stuff */
 186         u8              had_frag;       /* >= 1 fragments have been sent */
 187         u32             lastseq;        /* MP: last sequence # received */
 188         int             speed;          /* speed of the corresponding ppp channel*/
 189 #endif /* CONFIG_PPP_MULTILINK */
 190 };
 191
 192 struct ppp_config {
 193         struct file *file;
 194         s32 unit;
 195         bool ifname_is_set;
 196 };
 197
 198 /*
 199  * SMP locking issues:
 200  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 201  * list and the ppp.n_channels field, you need to take both locks
 202  * before you modify them.
 203  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 204  * channel.downl.
 205  */
 206
 207 static DEFINE_MUTEX(ppp_mutex);
 208 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 209 static atomic_t channel_count = ATOMIC_INIT(0);
 210
 211 /* per-net private data for this module */
 212 static unsigned int ppp_net_id __read_mostly;
 213 struct ppp_net {
 214         /* units to ppp mapping */
 215         struct idr units_idr;
 216
 217         /*
 218          * all_ppp_mutex protects the units_idr mapping.
 219          * It also ensures that finding a ppp unit in the units_idr
 220          * map and updating its file.refcnt field is atomic.
 221          */
 222         struct mutex all_ppp_mutex;
 223
 224         /* channels */
 225         struct list_head all_channels;
 226         struct list_head new_channels;
 227         int last_channel_index;
 228
 229         /*
 230          * all_channels_lock protects all_channels and
 231          * last_channel_index, and the atomicity of find
 232          * a channel and updating its file.refcnt field.
 233          */
 234         spinlock_t all_channels_lock;
 235 };
 236
 237 /* Get the PPP protocol number from a skb */
 238 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 239
 240 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 241 #define PPP_MAX_RQLEN   32
 242
 243 /*
 244  * Maximum number of multilink fragments queued up.
 245  * This has to be large enough to cope with the maximum latency of
 246  * the slowest channel relative to the others.  Strictly it should
 247  * depend on the number of channels and their characteristics.
 248  */
 249 #define PPP_MP_MAX_QLEN 128
 250
 251 /* Multilink header bits. */
 252 #define B       0x80            /* this fragment begins a packet */
 253 #define E       0x40            /* this fragment ends a packet */
 254
 255 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 256 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 257 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 258
 259 /* Prototypes. */
 260 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 261                         struct file *file, unsigned int cmd, unsigned long arg);
 262 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 263 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 264 static void ppp_push(struct ppp *ppp);
 265 static void ppp_channel_push(struct channel *pch);
 266 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 267                               struct channel *pch);
 268 static void ppp_receive_error(struct ppp *ppp);
 269 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 270 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 271                                             struct sk_buff *skb);
 272 #ifdef CONFIG_PPP_MULTILINK
 273 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 274                                 struct channel *pch);
 275 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 276 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 277 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 278 #endif /* CONFIG_PPP_MULTILINK */
 279 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 280 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 281 static void ppp_ccp_closed(struct ppp *ppp);
 282 static struct compressor *find_compressor(int type);
 283 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 284 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 285 static void init_ppp_file(struct ppp_file *pf, int kind);
 286 static void ppp_destroy_interface(struct ppp *ppp);
 287 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 288 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 289 static int ppp_connect_channel(struct channel *pch, int unit);
 290 static int ppp_disconnect_channel(struct channel *pch);
 291 static void ppp_destroy_channel(struct channel *pch);
 292 static int unit_get(struct idr *p, void *ptr, int min);
 293 static int unit_set(struct idr *p, void *ptr, int n);
 294 static void unit_put(struct idr *p, int n);
 295 static void *unit_find(struct idr *p, int n);
 296 static void ppp_setup(struct net_device *dev);
 297
 298 static const struct net_device_ops ppp_netdev_ops;
 299
 300 static struct class *ppp_class;
 301
 302 /* per net-namespace data */
 303 static inline struct ppp_net *ppp_pernet(struct net *net)
 304 {
 305         BUG_ON(!net);
 306
 307         return net_generic(net, ppp_net_id);
 308 }
 309
 310 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 311 static inline int proto_to_npindex(int proto)
 312 {
 313         switch (proto) {
 314         case PPP_IP:
 315                 return NP_IP;
 316         case PPP_IPV6:
 317                 return NP_IPV6;
 318         case PPP_IPX:
 319                 return NP_IPX;
 320         case PPP_AT:
 321                 return NP_AT;
 322         case PPP_MPLS_UC:
 323                 return NP_MPLS_UC;
 324         case PPP_MPLS_MC:
 325                 return NP_MPLS_MC;
 326         }
 327         return -EINVAL;
 328 }
 329
 330 /* Translates an NP index into a PPP protocol number */
 331 static const int npindex_to_proto[NUM_NP] = {
 332         PPP_IP,
 333         PPP_IPV6,
 334         PPP_IPX,
 335         PPP_AT,
 336         PPP_MPLS_UC,
 337         PPP_MPLS_MC,
 338 };
 339
 340 /* Translates an ethertype into an NP index */
 341 static inline int ethertype_to_npindex(int ethertype)
 342 {
 343         switch (ethertype) {
 344         case ETH_P_IP:
 345                 return NP_IP;
 346         case ETH_P_IPV6:
 347                 return NP_IPV6;
 348         case ETH_P_IPX:
 349                 return NP_IPX;
 350         case ETH_P_PPPTALK:
 351         case ETH_P_ATALK:
 352                 return NP_AT;
 353         case ETH_P_MPLS_UC:
 354                 return NP_MPLS_UC;
 355         case ETH_P_MPLS_MC:
 356                 return NP_MPLS_MC;
 357         }
 358         return -1;
 359 }
 360
 361 /* Translates an NP index into an ethertype */
 362 static const int npindex_to_ethertype[NUM_NP] = {
 363         ETH_P_IP,
 364         ETH_P_IPV6,
 365         ETH_P_IPX,
 366         ETH_P_PPPTALK,
 367         ETH_P_MPLS_UC,
 368         ETH_P_MPLS_MC,
 369 };
 370
 371 /*
 372  * Locking shorthand.
 373  */
 374 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 375 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 376 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 377 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 378 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 379                                      ppp_recv_lock(ppp); } while (0)
 380 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 381                                      ppp_xmit_unlock(ppp); } while (0)
 382
 383 /*
 384  * /dev/ppp device routines.
 385  * The /dev/ppp device is used by pppd to control the ppp unit.
 386  * It supports the read, write, ioctl and poll functions.
 387  * Open instances of /dev/ppp can be in one of three states:
 388  * unattached, attached to a ppp unit, or attached to a ppp channel.
 389  */
 390 static int ppp_open(struct inode *inode, struct file *file)
 391 {
 392         /*
 393          * This could (should?) be enforced by the permissions on /dev/ppp.
 394          */
 395         if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
 396                 return -EPERM;
 397         return 0;
 398 }
 399
 400 static int ppp_release(struct inode *unused, struct file *file)
 401 {
 402         struct ppp_file *pf = file->private_data;
 403         struct ppp *ppp;
 404
 405         if (pf) {
 406                 file->private_data = NULL;
 407                 if (pf->kind == INTERFACE) {
 408                         ppp = PF_TO_PPP(pf);
 409                         rtnl_lock();
 410                         if (file == ppp->owner)
 411                                 unregister_netdevice(ppp->dev);
 412                         rtnl_unlock();
 413                 }
 414                 if (refcount_dec_and_test(&pf->refcnt)) {
 415                         switch (pf->kind) {
 416                         case INTERFACE:
 417                                 ppp_destroy_interface(PF_TO_PPP(pf));
 418                                 break;
 419                         case CHANNEL:
 420                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 421                                 break;
 422                         }
 423                 }
 424         }
 425         return 0;
 426 }
 427
 428 static ssize_t ppp_read(struct file *file, char __user *buf,
 429                         size_t count, loff_t *ppos)
 430 {
 431         struct ppp_file *pf = file->private_data;
 432         DECLARE_WAITQUEUE(wait, current);
 433         ssize_t ret;
 434         struct sk_buff *skb = NULL;
 435         struct iovec iov;
 436         struct iov_iter to;
 437
 438         ret = count;
 439
 440         if (!pf)
 441                 return -ENXIO;
 442         add_wait_queue(&pf->rwait, &wait);
 443         for (;;) {
 444                 set_current_state(TASK_INTERRUPTIBLE);
 445                 skb = skb_dequeue(&pf->rq);
 446                 if (skb)
 447                         break;
 448                 ret = 0;
 449                 if (pf->dead)
 450                         break;
 451                 if (pf->kind == INTERFACE) {
 452                         /*
 453                          * Return 0 (EOF) on an interface that has no
 454                          * channels connected, unless it is looping
 455                          * network traffic (demand mode).
 456                          */
 457                         struct ppp *ppp = PF_TO_PPP(pf);
 458
 459                         ppp_recv_lock(ppp);
 460                         if (ppp->n_channels == 0 &&
 461                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 462                                 ppp_recv_unlock(ppp);
 463                                 break;
 464                         }
 465                         ppp_recv_unlock(ppp);
 466                 }
 467                 ret = -EAGAIN;
 468                 if (file->f_flags & O_NONBLOCK)
 469                         break;
 470                 ret = -ERESTARTSYS;
 471                 if (signal_pending(current))
 472                         break;
 473                 schedule();
 474         }
 475         set_current_state(TASK_RUNNING);
 476         remove_wait_queue(&pf->rwait, &wait);
 477
 478         if (!skb)
 479                 goto out;
 480
 481         ret = -EOVERFLOW;
 482         if (skb->len > count)
 483                 goto outf;
 484         ret = -EFAULT;
 485         iov.iov_base = buf;
 486         iov.iov_len = count;
 487         iov_iter_init(&to, READ, &iov, 1, count);
 488         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 489                 goto outf;
 490         ret = skb->len;
 491
 492  outf:
 493         kfree_skb(skb);
 494  out:
 495         return ret;
 496 }
 497
 498 static ssize_t ppp_write(struct file *file, const char __user *buf,
 499                          size_t count, loff_t *ppos)
 500 {
 501         struct ppp_file *pf = file->private_data;
 502         struct sk_buff *skb;
 503         ssize_t ret;
 504
 505         if (!pf)
 506                 return -ENXIO;
 507         /* All PPP packets should start with the 2-byte protocol */
 508         if (count < PPP_PROTO_LEN)
 509                 return -EINVAL;
 510         ret = -ENOMEM;
 511         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 512         if (!skb)
 513                 goto out;
 514         skb_reserve(skb, pf->hdrlen);
 515         ret = -EFAULT;
 516         if (copy_from_user(skb_put(skb, count), buf, count)) {
 517                 kfree_skb(skb);
 518                 goto out;
 519         }
 520
 521         switch (pf->kind) {
 522         case INTERFACE:
 523                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 524                 break;
 525         case CHANNEL:
 526                 skb_queue_tail(&pf->xq, skb);
 527                 ppp_channel_push(PF_TO_CHANNEL(pf));
 528                 break;
 529         }
 530
 531         ret = count;
 532
 533  out:
 534         return ret;
 535 }
 536
 537 /* No kernel lock - fine */
 538 static __poll_t ppp_poll(struct file *file, poll_table *wait)
 539 {
 540         struct ppp_file *pf = file->private_data;
 541         __poll_t mask;
 542
 543         if (!pf)
 544                 return 0;
 545         poll_wait(file, &pf->rwait, wait);
 546         mask = EPOLLOUT | EPOLLWRNORM;
 547         if (skb_peek(&pf->rq))
 548                 mask |= EPOLLIN | EPOLLRDNORM;
 549         if (pf->dead)
 550                 mask |= EPOLLHUP;
 551         else if (pf->kind == INTERFACE) {
 552                 /* see comment in ppp_read */
 553                 struct ppp *ppp = PF_TO_PPP(pf);
 554
 555                 ppp_recv_lock(ppp);
 556                 if (ppp->n_channels == 0 &&
 557                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 558                         mask |= EPOLLIN | EPOLLRDNORM;
 559                 ppp_recv_unlock(ppp);
 560         }
 561
 562         return mask;
 563 }
 564
 565 #ifdef CONFIG_PPP_FILTER
 566 static int get_filter(void __user *arg, struct sock_filter **p)
 567 {
 568         struct sock_fprog uprog;
 569         struct sock_filter *code = NULL;
 570         int len;
 571
 572         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 573                 return -EFAULT;
 574
 575         if (!uprog.len) {
 576                 *p = NULL;
 577                 return 0;
 578         }
 579
 580         len = uprog.len * sizeof(struct sock_filter);
 581         code = memdup_user(uprog.filter, len);
 582         if (IS_ERR(code))
 583                 return PTR_ERR(code);
 584
 585         *p = code;
 586         return uprog.len;
 587 }
 588 #endif /* CONFIG_PPP_FILTER */
 589
 590 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 591 {
 592         struct ppp_file *pf;
 593         struct ppp *ppp;
 594         int err = -EFAULT, val, val2, i;
 595         struct ppp_idle idle;
 596         struct npioctl npi;
 597         int unit, cflags;
 598         struct slcompress *vj;
 599         void __user *argp = (void __user *)arg;
 600         int __user *p = argp;
 601
 602         mutex_lock(&ppp_mutex);
 603
 604         pf = file->private_data;
 605         if (!pf) {
 606                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 607                                            pf, file, cmd, arg);
 608                 goto out;
 609         }
 610
 611         if (cmd == PPPIOCDETACH) {
 612                 /*
 613                  * PPPIOCDETACH is no longer supported as it was heavily broken,
 614                  * and is only known to have been used by pppd older than
 615                  * ppp-2.4.2 (released November 2003).
 616                  */
 617                 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
 618                              current->comm, current->pid);
 619                 err = -EINVAL;
 620                 goto out;
 621         }
 622
 623         if (pf->kind == CHANNEL) {
 624                 struct channel *pch;
 625                 struct ppp_channel *chan;
 626
 627                 pch = PF_TO_CHANNEL(pf);
 628
 629                 switch (cmd) {
 630                 case PPPIOCCONNECT:
 631                         if (get_user(unit, p))
 632                                 break;
 633                         err = ppp_connect_channel(pch, unit);
 634                         break;
 635
 636                 case PPPIOCDISCONN:
 637                         err = ppp_disconnect_channel(pch);
 638                         break;
 639
 640                 default:
 641                         down_read(&pch->chan_sem);
 642                         chan = pch->chan;
 643                         err = -ENOTTY;
 644                         if (chan && chan->ops->ioctl)
 645                                 err = chan->ops->ioctl(chan, cmd, arg);
 646                         up_read(&pch->chan_sem);
 647                 }
 648                 goto out;
 649         }
 650
 651         if (pf->kind != INTERFACE) {
 652                 /* can't happen */
 653                 pr_err("PPP: not interface or channel??\n");
 654                 err = -EINVAL;
 655                 goto out;
 656         }
 657
 658         ppp = PF_TO_PPP(pf);
 659         switch (cmd) {
 660         case PPPIOCSMRU:
 661                 if (get_user(val, p))
 662                         break;
 663                 ppp->mru = val;
 664                 err = 0;
 665                 break;
 666
 667         case PPPIOCSFLAGS:
 668                 if (get_user(val, p))
 669                         break;
 670                 ppp_lock(ppp);
 671                 cflags = ppp->flags & ~val;
 672 #ifdef CONFIG_PPP_MULTILINK
 673                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 674                         ppp->nextseq = 0;
 675 #endif
 676                 ppp->flags = val & SC_FLAG_BITS;
 677                 ppp_unlock(ppp);
 678                 if (cflags & SC_CCP_OPEN)
 679                         ppp_ccp_closed(ppp);
 680                 err = 0;
 681                 break;
 682
 683         case PPPIOCGFLAGS:
 684                 val = ppp->flags | ppp->xstate | ppp->rstate;
 685                 if (put_user(val, p))
 686                         break;
 687                 err = 0;
 688                 break;
 689
 690         case PPPIOCSCOMPRESS:
 691                 err = ppp_set_compress(ppp, arg);
 692                 break;
 693
 694         case PPPIOCGUNIT:
 695                 if (put_user(ppp->file.index, p))
 696                         break;
 697                 err = 0;
 698                 break;
 699
 700         case PPPIOCSDEBUG:
 701                 if (get_user(val, p))
 702                         break;
 703                 ppp->debug = val;
 704                 err = 0;
 705                 break;
 706
 707         case PPPIOCGDEBUG:
 708                 if (put_user(ppp->debug, p))
 709                         break;
 710                 err = 0;
 711                 break;
 712
 713         case PPPIOCGIDLE:
 714                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 715                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 716                 if (copy_to_user(argp, &idle, sizeof(idle)))
 717                         break;
 718                 err = 0;
 719                 break;
 720
 721         case PPPIOCSMAXCID:
 722                 if (get_user(val, p))
 723                         break;
 724                 val2 = 15;
 725                 if ((val >> 16) != 0) {
 726                         val2 = val >> 16;
 727                         val &= 0xffff;
 728                 }
 729                 vj = slhc_init(val2+1, val+1);
 730                 if (IS_ERR(vj)) {
 731                         err = PTR_ERR(vj);
 732                         break;
 733                 }
 734                 ppp_lock(ppp);
 735                 if (ppp->vj)
 736                         slhc_free(ppp->vj);
 737                 ppp->vj = vj;
 738                 ppp_unlock(ppp);
 739                 err = 0;
 740                 break;
 741
 742         case PPPIOCGNPMODE:
 743         case PPPIOCSNPMODE:
 744                 if (copy_from_user(&npi, argp, sizeof(npi)))
 745                         break;
 746                 err = proto_to_npindex(npi.protocol);
 747                 if (err < 0)
 748                         break;
 749                 i = err;
 750                 if (cmd == PPPIOCGNPMODE) {
 751                         err = -EFAULT;
 752                         npi.mode = ppp->npmode[i];
 753                         if (copy_to_user(argp, &npi, sizeof(npi)))
 754                                 break;
 755                 } else {
 756                         ppp->npmode[i] = npi.mode;
 757                         /* we may be able to transmit more packets now (??) */
 758                         netif_wake_queue(ppp->dev);
 759                 }
 760                 err = 0;
 761                 break;
 762
 763 #ifdef CONFIG_PPP_FILTER
 764         case PPPIOCSPASS:
 765         {
 766                 struct sock_filter *code;
 767
 768                 err = get_filter(argp, &code);
 769                 if (err >= 0) {
 770                         struct bpf_prog *pass_filter = NULL;
 771                         struct sock_fprog_kern fprog = {
 772                                 .len = err,
 773                                 .filter = code,
 774                         };
 775
 776                         err = 0;
 777                         if (fprog.filter)
 778                                 err = bpf_prog_create(&pass_filter, &fprog);
 779                         if (!err) {
 780                                 ppp_lock(ppp);
 781                                 if (ppp->pass_filter)
 782                                         bpf_prog_destroy(ppp->pass_filter);
 783                                 ppp->pass_filter = pass_filter;
 784                                 ppp_unlock(ppp);
 785                         }
 786                         kfree(code);
 787                 }
 788                 break;
 789         }
 790         case PPPIOCSACTIVE:
 791         {
 792                 struct sock_filter *code;
 793
 794                 err = get_filter(argp, &code);
 795                 if (err >= 0) {
 796                         struct bpf_prog *active_filter = NULL;
 797                         struct sock_fprog_kern fprog = {
 798                                 .len = err,
 799                                 .filter = code,
 800                         };
 801
 802                         err = 0;
 803                         if (fprog.filter)
 804                                 err = bpf_prog_create(&active_filter, &fprog);
 805                         if (!err) {
 806                                 ppp_lock(ppp);
 807                                 if (ppp->active_filter)
 808                                         bpf_prog_destroy(ppp->active_filter);
 809                                 ppp->active_filter = active_filter;
 810                                 ppp_unlock(ppp);
 811                         }
 812                         kfree(code);
 813                 }
 814                 break;
 815         }
 816 #endif /* CONFIG_PPP_FILTER */
 817
 818 #ifdef CONFIG_PPP_MULTILINK
 819         case PPPIOCSMRRU:
 820                 if (get_user(val, p))
 821                         break;
 822                 ppp_recv_lock(ppp);
 823                 ppp->mrru = val;
 824                 ppp_recv_unlock(ppp);
 825                 err = 0;
 826                 break;
 827 #endif /* CONFIG_PPP_MULTILINK */
 828
 829         default:
 830                 err = -ENOTTY;
 831         }
 832
 833 out:
 834         mutex_unlock(&ppp_mutex);
 835
 836         return err;
 837 }
 838
 839 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 840                         struct file *file, unsigned int cmd, unsigned long arg)
 841 {
 842         int unit, err = -EFAULT;
 843         struct ppp *ppp;
 844         struct channel *chan;
 845         struct ppp_net *pn;
 846         int __user *p = (int __user *)arg;
 847
 848         switch (cmd) {
 849         case PPPIOCNEWUNIT:
 850                 /* Create a new ppp unit */
 851                 if (get_user(unit, p))
 852                         break;
 853                 err = ppp_create_interface(net, file, &unit);
 854                 if (err < 0)
 855                         break;
 856
 857                 err = -EFAULT;
 858                 if (put_user(unit, p))
 859                         break;
 860                 err = 0;
 861                 break;
 862
 863         case PPPIOCATTACH:
 864                 /* Attach to an existing ppp unit */
 865                 if (get_user(unit, p))
 866                         break;
 867                 err = -ENXIO;
 868                 pn = ppp_pernet(net);
 869                 mutex_lock(&pn->all_ppp_mutex);
 870                 ppp = ppp_find_unit(pn, unit);
 871                 if (ppp) {
 872                         refcount_inc(&ppp->file.refcnt);
 873                         file->private_data = &ppp->file;
 874                         err = 0;
 875                 }
 876                 mutex_unlock(&pn->all_ppp_mutex);
 877                 break;
 878
 879         case PPPIOCATTCHAN:
 880                 if (get_user(unit, p))
 881                         break;
 882                 err = -ENXIO;
 883                 pn = ppp_pernet(net);
 884                 spin_lock_bh(&pn->all_channels_lock);
 885                 chan = ppp_find_channel(pn, unit);
 886                 if (chan) {
 887                         refcount_inc(&chan->file.refcnt);
 888                         file->private_data = &chan->file;
 889                         err = 0;
 890                 }
 891                 spin_unlock_bh(&pn->all_channels_lock);
 892                 break;
 893
 894         default:
 895                 err = -ENOTTY;
 896         }
 897
 898         return err;
 899 }
 900
 901 static const struct file_operations ppp_device_fops = {
 902         .owner          = THIS_MODULE,
 903         .read           = ppp_read,
 904         .write          = ppp_write,
 905         .poll           = ppp_poll,
 906         .unlocked_ioctl = ppp_ioctl,
 907         .open           = ppp_open,
 908         .release        = ppp_release,
 909         .llseek         = noop_llseek,
 910 };
 911
 912 static __net_init int ppp_init_net(struct net *net)
 913 {
 914         struct ppp_net *pn = net_generic(net, ppp_net_id);
 915
 916         idr_init(&pn->units_idr);
 917         mutex_init(&pn->all_ppp_mutex);
 918
 919         INIT_LIST_HEAD(&pn->all_channels);
 920         INIT_LIST_HEAD(&pn->new_channels);
 921
 922         spin_lock_init(&pn->all_channels_lock);
 923
 924         return 0;
 925 }
 926
 927 static __net_exit void ppp_exit_net(struct net *net)
 928 {
 929         struct ppp_net *pn = net_generic(net, ppp_net_id);
 930         struct net_device *dev;
 931         struct net_device *aux;
 932         struct ppp *ppp;
 933         LIST_HEAD(list);
 934         int id;
 935
 936         rtnl_lock();
 937         for_each_netdev_safe(net, dev, aux) {
 938                 if (dev->netdev_ops == &ppp_netdev_ops)
 939                         unregister_netdevice_queue(dev, &list);
 940         }
 941
 942         idr_for_each_entry(&pn->units_idr, ppp, id)
 943                 /* Skip devices already unregistered by previous loop */
 944                 if (!net_eq(dev_net(ppp->dev), net))
 945                         unregister_netdevice_queue(ppp->dev, &list);
 946
 947         unregister_netdevice_many(&list);
 948         rtnl_unlock();
 949
 950         mutex_destroy(&pn->all_ppp_mutex);
 951         idr_destroy(&pn->units_idr);
 952         WARN_ON_ONCE(!list_empty(&pn->all_channels));
 953         WARN_ON_ONCE(!list_empty(&pn->new_channels));
 954 }
 955
 956 static struct pernet_operations ppp_net_ops = {
 957         .init = ppp_init_net,
 958         .exit = ppp_exit_net,
 959         .id   = &ppp_net_id,
 960         .size = sizeof(struct ppp_net),
 961 };
 962
 963 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
 964 {
 965         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
 966         int ret;
 967
 968         mutex_lock(&pn->all_ppp_mutex);
 969
 970         if (unit < 0) {
 971                 ret = unit_get(&pn->units_idr, ppp, 0);
 972                 if (ret < 0)
 973                         goto err;
 974                 if (!ifname_is_set) {
 975                         while (1) {
 976                                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
 977                                 if (!__dev_get_by_name(ppp->ppp_net, ppp->dev->name))
 978                                         break;
 979                                 unit_put(&pn->units_idr, ret);
 980                                 ret = unit_get(&pn->units_idr, ppp, ret + 1);
 981                                 if (ret < 0)
 982                                         goto err;
 983                         }
 984                 }
 985         } else {
 986                 /* Caller asked for a specific unit number. Fail with -EEXIST
 987                  * if unavailable. For backward compatibility, return -EEXIST
 988                  * too if idr allocation fails; this makes pppd retry without
 989                  * requesting a specific unit number.
 990                  */
 991                 if (unit_find(&pn->units_idr, unit)) {
 992                         ret = -EEXIST;
 993                         goto err;
 994                 }
 995                 ret = unit_set(&pn->units_idr, ppp, unit);
 996                 if (ret < 0) {
 997                         /* Rewrite error for backward compatibility */
 998                         ret = -EEXIST;
 999                         goto err;
1000                 }
1001         }
1002         ppp->file.index = ret;
1003
1004         if (!ifname_is_set)
1005                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1006
1007         mutex_unlock(&pn->all_ppp_mutex);
1008
1009         ret = register_netdevice(ppp->dev);
1010         if (ret < 0)
1011                 goto err_unit;
1012
1013         atomic_inc(&ppp_unit_count);
1014
1015         return 0;
1016
1017 err_unit:
1018         mutex_lock(&pn->all_ppp_mutex);
1019         unit_put(&pn->units_idr, ppp->file.index);
1020 err:
1021         mutex_unlock(&pn->all_ppp_mutex);
1022
1023         return ret;
1024 }
1025
1026 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1027                              const struct ppp_config *conf)
1028 {
1029         struct ppp *ppp = netdev_priv(dev);
1030         int indx;
1031         int err;
1032         int cpu;
1033
1034         ppp->dev = dev;
1035         ppp->ppp_net = src_net;
1036         ppp->mru = PPP_MRU;
1037         ppp->owner = conf->file;
1038
1039         init_ppp_file(&ppp->file, INTERFACE);
1040         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1041
1042         for (indx = 0; indx < NUM_NP; ++indx)
1043                 ppp->npmode[indx] = NPMODE_PASS;
1044         INIT_LIST_HEAD(&ppp->channels);
1045         spin_lock_init(&ppp->rlock);
1046         spin_lock_init(&ppp->wlock);
1047
1048         ppp->xmit_recursion = alloc_percpu(int);
1049         if (!ppp->xmit_recursion) {
1050                 err = -ENOMEM;
1051                 goto err1;
1052         }
1053         for_each_possible_cpu(cpu)
1054                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1055
1056 #ifdef CONFIG_PPP_MULTILINK
1057         ppp->minseq = -1;
1058         skb_queue_head_init(&ppp->mrq);
1059 #endif /* CONFIG_PPP_MULTILINK */
1060 #ifdef CONFIG_PPP_FILTER
1061         ppp->pass_filter = NULL;
1062         ppp->active_filter = NULL;
1063 #endif /* CONFIG_PPP_FILTER */
1064
1065         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1066         if (err < 0)
1067                 goto err2;
1068
1069         conf->file->private_data = &ppp->file;
1070
1071         return 0;
1072 err2:
1073         free_percpu(ppp->xmit_recursion);
1074 err1:
1075         return err;
1076 }
1077
1078 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1079         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1080 };
1081
1082 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1083                            struct netlink_ext_ack *extack)
1084 {
1085         if (!data)
1086                 return -EINVAL;
1087
1088         if (!data[IFLA_PPP_DEV_FD])
1089                 return -EINVAL;
1090         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1091                 return -EBADF;
1092
1093         return 0;
1094 }
1095
1096 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1097                           struct nlattr *tb[], struct nlattr *data[],
1098                           struct netlink_ext_ack *extack)
1099 {
1100         struct ppp_config conf = {
1101                 .unit = -1,
1102                 .ifname_is_set = true,
1103         };
1104         struct file *file;
1105         int err;
1106
1107         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1108         if (!file)
1109                 return -EBADF;
1110
1111         /* rtnl_lock is already held here, but ppp_create_interface() locks
1112          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1113          * possible deadlock due to lock order inversion, at the cost of
1114          * pushing the problem back to userspace.
1115          */
1116         if (!mutex_trylock(&ppp_mutex)) {
1117                 err = -EBUSY;
1118                 goto out;
1119         }
1120
1121         if (file->f_op != &ppp_device_fops || file->private_data) {
1122                 err = -EBADF;
1123                 goto out_unlock;
1124         }
1125
1126         conf.file = file;
1127
1128         /* Don't use device name generated by the rtnetlink layer when ifname
1129          * isn't specified. Let ppp_dev_configure() set the device name using
1130          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1131          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1132          */
1133         if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1134                 conf.ifname_is_set = false;
1135
1136         err = ppp_dev_configure(src_net, dev, &conf);
1137
1138 out_unlock:
1139         mutex_unlock(&ppp_mutex);
1140 out:
1141         fput(file);
1142
1143         return err;
1144 }
1145
1146 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1147 {
1148         unregister_netdevice_queue(dev, head);
1149 }
1150
1151 static size_t ppp_nl_get_size(const struct net_device *dev)
1152 {
1153         return 0;
1154 }
1155
1156 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1157 {
1158         return 0;
1159 }
1160
1161 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1162 {
1163         struct ppp *ppp = netdev_priv(dev);
1164
1165         return ppp->ppp_net;
1166 }
1167
1168 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1169         .kind           = "ppp",
1170         .maxtype        = IFLA_PPP_MAX,
1171         .policy         = ppp_nl_policy,
1172         .priv_size      = sizeof(struct ppp),
1173         .setup          = ppp_setup,
1174         .validate       = ppp_nl_validate,
1175         .newlink        = ppp_nl_newlink,
1176         .dellink        = ppp_nl_dellink,
1177         .get_size       = ppp_nl_get_size,
1178         .fill_info      = ppp_nl_fill_info,
1179         .get_link_net   = ppp_nl_get_link_net,
1180 };
1181
1182 #define PPP_MAJOR       108
1183
1184 /* Called at boot time if ppp is compiled into the kernel,
1185    or at module load time (from init_module) if compiled as a module. */
1186 static int __init ppp_init(void)
1187 {
1188         int err;
1189
1190         pr_info("PPP generic driver version " PPP_VERSION "\n");
1191
1192         err = register_pernet_device(&ppp_net_ops);
1193         if (err) {
1194                 pr_err("failed to register PPP pernet device (%d)\n", err);
1195                 goto out;
1196         }
1197
1198         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1199         if (err) {
1200                 pr_err("failed to register PPP device (%d)\n", err);
1201                 goto out_net;
1202         }
1203
1204         ppp_class = class_create(THIS_MODULE, "ppp");
1205         if (IS_ERR(ppp_class)) {
1206                 err = PTR_ERR(ppp_class);
1207                 goto out_chrdev;
1208         }
1209
1210         err = rtnl_link_register(&ppp_link_ops);
1211         if (err) {
1212                 pr_err("failed to register rtnetlink PPP handler\n");
1213                 goto out_class;
1214         }
1215
1216         /* not a big deal if we fail here :-) */
1217         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1218
1219         return 0;
1220
1221 out_class:
1222         class_destroy(ppp_class);
1223 out_chrdev:
1224         unregister_chrdev(PPP_MAJOR, "ppp");
1225 out_net:
1226         unregister_pernet_device(&ppp_net_ops);
1227 out:
1228         return err;
1229 }
1230
1231 /*
1232  * Network interface unit routines.
1233  */
1234 static netdev_tx_t
1235 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1236 {
1237         struct ppp *ppp = netdev_priv(dev);
1238         int npi, proto;
1239         unsigned char *pp;
1240
1241         npi = ethertype_to_npindex(ntohs(skb->protocol));
1242         if (npi < 0)
1243                 goto outf;
1244
1245         /* Drop, accept or reject the packet */
1246         switch (ppp->npmode[npi]) {
1247         case NPMODE_PASS:
1248                 break;
1249         case NPMODE_QUEUE:
1250                 /* it would be nice to have a way to tell the network
1251                    system to queue this one up for later. */
1252                 goto outf;
1253         case NPMODE_DROP:
1254         case NPMODE_ERROR:
1255                 goto outf;
1256         }
1257
1258         /* Put the 2-byte PPP protocol number on the front,
1259            making sure there is room for the address and control fields. */
1260         if (skb_cow_head(skb, PPP_HDRLEN))
1261                 goto outf;
1262
1263         pp = skb_push(skb, 2);
1264         proto = npindex_to_proto[npi];
1265         put_unaligned_be16(proto, pp);
1266
1267         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1268         ppp_xmit_process(ppp, skb);
1269
1270         return NETDEV_TX_OK;
1271
1272  outf:
1273         kfree_skb(skb);
1274         ++dev->stats.tx_dropped;
1275         return NETDEV_TX_OK;
1276 }
1277
1278 static int
1279 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1280 {
1281         struct ppp *ppp = netdev_priv(dev);
1282         int err = -EFAULT;
1283         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1284         struct ppp_stats stats;
1285         struct ppp_comp_stats cstats;
1286         char *vers;
1287
1288         switch (cmd) {
1289         case SIOCGPPPSTATS:
1290                 ppp_get_stats(ppp, &stats);
1291                 if (copy_to_user(addr, &stats, sizeof(stats)))
1292                         break;
1293                 err = 0;
1294                 break;
1295
1296         case SIOCGPPPCSTATS:
1297                 memset(&cstats, 0, sizeof(cstats));
1298                 if (ppp->xc_state)
1299                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1300                 if (ppp->rc_state)
1301                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1302                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1303                         break;
1304                 err = 0;
1305                 break;
1306
1307         case SIOCGPPPVER:
1308                 vers = PPP_VERSION;
1309                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1310                         break;
1311                 err = 0;
1312                 break;
1313
1314         default:
1315                 err = -EINVAL;
1316         }
1317
1318         return err;
1319 }
1320
1321 static void
1322 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1323 {
1324         struct ppp *ppp = netdev_priv(dev);
1325
1326         ppp_recv_lock(ppp);
1327         stats64->rx_packets = ppp->stats64.rx_packets;
1328         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1329         ppp_recv_unlock(ppp);
1330
1331         ppp_xmit_lock(ppp);
1332         stats64->tx_packets = ppp->stats64.tx_packets;
1333         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1334         ppp_xmit_unlock(ppp);
1335
1336         stats64->rx_errors        = dev->stats.rx_errors;
1337         stats64->tx_errors        = dev->stats.tx_errors;
1338         stats64->rx_dropped       = dev->stats.rx_dropped;
1339         stats64->tx_dropped       = dev->stats.tx_dropped;
1340         stats64->rx_length_errors = dev->stats.rx_length_errors;
1341 }
1342
1343 static int ppp_dev_init(struct net_device *dev)
1344 {
1345         struct ppp *ppp;
1346
1347         netdev_lockdep_set_classes(dev);
1348
1349         ppp = netdev_priv(dev);
1350         /* Let the netdevice take a reference on the ppp file. This ensures
1351          * that ppp_destroy_interface() won't run before the device gets
1352          * unregistered.
1353          */
1354         refcount_inc(&ppp->file.refcnt);
1355
1356         return 0;
1357 }
1358
1359 static void ppp_dev_uninit(struct net_device *dev)
1360 {
1361         struct ppp *ppp = netdev_priv(dev);
1362         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1363
1364         ppp_lock(ppp);
1365         ppp->closing = 1;
1366         ppp_unlock(ppp);
1367
1368         mutex_lock(&pn->all_ppp_mutex);
1369         unit_put(&pn->units_idr, ppp->file.index);
1370         mutex_unlock(&pn->all_ppp_mutex);
1371
1372         ppp->owner = NULL;
1373
1374         ppp->file.dead = 1;
1375         wake_up_interruptible(&ppp->file.rwait);
1376 }
1377
1378 static void ppp_dev_priv_destructor(struct net_device *dev)
1379 {
1380         struct ppp *ppp;
1381
1382         ppp = netdev_priv(dev);
1383         if (refcount_dec_and_test(&ppp->file.refcnt))
1384                 ppp_destroy_interface(ppp);
1385 }
1386
1387 static const struct net_device_ops ppp_netdev_ops = {
1388         .ndo_init        = ppp_dev_init,
1389         .ndo_uninit      = ppp_dev_uninit,
1390         .ndo_start_xmit  = ppp_start_xmit,
1391         .ndo_do_ioctl    = ppp_net_ioctl,
1392         .ndo_get_stats64 = ppp_get_stats64,
1393 };
1394
1395 static struct device_type ppp_type = {
1396         .name = "ppp",
1397 };
1398
1399 static void ppp_setup(struct net_device *dev)
1400 {
1401         dev->netdev_ops = &ppp_netdev_ops;
1402         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1403
1404         dev->features |= NETIF_F_LLTX;
1405
1406         dev->hard_header_len = PPP_HDRLEN;
1407         dev->mtu = PPP_MRU;
1408         dev->addr_len = 0;
1409         dev->tx_queue_len = 3;
1410         dev->type = ARPHRD_PPP;
1411         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1412         dev->priv_destructor = ppp_dev_priv_destructor;
1413         netif_keep_dst(dev);
1414 }
1415
1416 /*
1417  * Transmit-side routines.
1418  */
1419
1420 /* Called to do any work queued up on the transmit side that can now be done */
1421 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1422 {
1423         ppp_xmit_lock(ppp);
1424         if (!ppp->closing) {
1425                 ppp_push(ppp);
1426
1427                 if (skb)
1428                         skb_queue_tail(&ppp->file.xq, skb);
1429                 while (!ppp->xmit_pending &&
1430                        (skb = skb_dequeue(&ppp->file.xq)))
1431                         ppp_send_frame(ppp, skb);
1432                 /* If there's no work left to do, tell the core net
1433                    code that we can accept some more. */
1434                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1435                         netif_wake_queue(ppp->dev);
1436                 else
1437                         netif_stop_queue(ppp->dev);
1438         } else {
1439                 kfree_skb(skb);
1440         }
1441         ppp_xmit_unlock(ppp);
1442 }
1443
1444 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1445 {
1446         local_bh_disable();
1447
1448         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1449                 goto err;
1450
1451         (*this_cpu_ptr(ppp->xmit_recursion))++;
1452         __ppp_xmit_process(ppp, skb);
1453         (*this_cpu_ptr(ppp->xmit_recursion))--;
1454
1455         local_bh_enable();
1456
1457         return;
1458
1459 err:
1460         local_bh_enable();
1461
1462         kfree_skb(skb);
1463
1464         if (net_ratelimit())
1465                 netdev_err(ppp->dev, "recursion detected\n");
1466 }
1467
1468 static inline struct sk_buff *
1469 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1470 {
1471         struct sk_buff *new_skb;
1472         int len;
1473         int new_skb_size = ppp->dev->mtu +
1474                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1475         int compressor_skb_size = ppp->dev->mtu +
1476                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1477         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1478         if (!new_skb) {
1479                 if (net_ratelimit())
1480                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1481                 return NULL;
1482         }
1483         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1484                 skb_reserve(new_skb,
1485                             ppp->dev->hard_header_len - PPP_HDRLEN);
1486
1487         /* compressor still expects A/C bytes in hdr */
1488         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1489                                    new_skb->data, skb->len + 2,
1490                                    compressor_skb_size);
1491         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1492                 consume_skb(skb);
1493                 skb = new_skb;
1494                 skb_put(skb, len);
1495                 skb_pull(skb, 2);       /* pull off A/C bytes */
1496         } else if (len == 0) {
1497                 /* didn't compress, or CCP not up yet */
1498                 consume_skb(new_skb);
1499                 new_skb = skb;
1500         } else {
1501                 /*
1502                  * (len < 0)
1503                  * MPPE requires that we do not send unencrypted
1504                  * frames.  The compressor will return -1 if we
1505                  * should drop the frame.  We cannot simply test
1506                  * the compress_proto because MPPE and MPPC share
1507                  * the same number.
1508                  */
1509                 if (net_ratelimit())
1510                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1511                 kfree_skb(skb);
1512                 consume_skb(new_skb);
1513                 new_skb = NULL;
1514         }
1515         return new_skb;
1516 }
1517
1518 /*
1519  * Compress and send a frame.
1520  * The caller should have locked the xmit path,
1521  * and xmit_pending should be 0.
1522  */
1523 static void
1524 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1525 {
1526         int proto = PPP_PROTO(skb);
1527         struct sk_buff *new_skb;
1528         int len;
1529         unsigned char *cp;
1530
1531         if (proto < 0x8000) {
1532 #ifdef CONFIG_PPP_FILTER
1533                 /* check if we should pass this packet */
1534                 /* the filter instructions are constructed assuming
1535                    a four-byte PPP header on each packet */
1536                 *(u8 *)skb_push(skb, 2) = 1;
1537                 if (ppp->pass_filter &&
1538                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1539                         if (ppp->debug & 1)
1540                                 netdev_printk(KERN_DEBUG, ppp->dev,
1541                                               "PPP: outbound frame "
1542                                               "not passed\n");
1543                         kfree_skb(skb);
1544                         return;
1545                 }
1546                 /* if this packet passes the active filter, record the time */
1547                 if (!(ppp->active_filter &&
1548                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1549                         ppp->last_xmit = jiffies;
1550                 skb_pull(skb, 2);
1551 #else
1552                 /* for data packets, record the time */
1553                 ppp->last_xmit = jiffies;
1554 #endif /* CONFIG_PPP_FILTER */
1555         }
1556
1557         ++ppp->stats64.tx_packets;
1558         ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1559
1560         switch (proto) {
1561         case PPP_IP:
1562                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1563                         break;
1564                 /* try to do VJ TCP header compression */
1565                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1566                                     GFP_ATOMIC);
1567                 if (!new_skb) {
1568                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1569                         goto drop;
1570                 }
1571                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1572                 cp = skb->data + 2;
1573                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1574                                     new_skb->data + 2, &cp,
1575                                     !(ppp->flags & SC_NO_TCP_CCID));
1576                 if (cp == skb->data + 2) {
1577                         /* didn't compress */
1578                         consume_skb(new_skb);
1579                 } else {
1580                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1581                                 proto = PPP_VJC_COMP;
1582                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1583                         } else {
1584                                 proto = PPP_VJC_UNCOMP;
1585                                 cp[0] = skb->data[2];
1586                         }
1587                         consume_skb(skb);
1588                         skb = new_skb;
1589                         cp = skb_put(skb, len + 2);
1590                         cp[0] = 0;
1591                         cp[1] = proto;
1592                 }
1593                 break;
1594
1595         case PPP_CCP:
1596                 /* peek at outbound CCP frames */
1597                 ppp_ccp_peek(ppp, skb, 0);
1598                 break;
1599         }
1600
1601         /* try to do packet compression */
1602         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1603             proto != PPP_LCP && proto != PPP_CCP) {
1604                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1605                         if (net_ratelimit())
1606                                 netdev_err(ppp->dev,
1607                                            "ppp: compression required but "
1608                                            "down - pkt dropped.\n");
1609                         goto drop;
1610                 }
1611                 skb = pad_compress_skb(ppp, skb);
1612                 if (!skb)
1613                         goto drop;
1614         }
1615
1616         /*
1617          * If we are waiting for traffic (demand dialling),
1618          * queue it up for pppd to receive.
1619          */
1620         if (ppp->flags & SC_LOOP_TRAFFIC) {
1621                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1622                         goto drop;
1623                 skb_queue_tail(&ppp->file.rq, skb);
1624                 wake_up_interruptible(&ppp->file.rwait);
1625                 return;
1626         }
1627
1628         ppp->xmit_pending = skb;
1629         ppp_push(ppp);
1630         return;
1631
1632  drop:
1633         kfree_skb(skb);
1634         ++ppp->dev->stats.tx_errors;
1635 }
1636
1637 /*
1638  * Try to send the frame in xmit_pending.
1639  * The caller should have the xmit path locked.
1640  */
1641 static void
1642 ppp_push(struct ppp *ppp)
1643 {
1644         struct list_head *list;
1645         struct channel *pch;
1646         struct sk_buff *skb = ppp->xmit_pending;
1647
1648         if (!skb)
1649                 return;
1650
1651         list = &ppp->channels;
1652         if (list_empty(list)) {
1653                 /* nowhere to send the packet, just drop it */
1654                 ppp->xmit_pending = NULL;
1655                 kfree_skb(skb);
1656                 return;
1657         }
1658
1659         if ((ppp->flags & SC_MULTILINK) == 0) {
1660                 /* not doing multilink: send it down the first channel */
1661                 list = list->next;
1662                 pch = list_entry(list, struct channel, clist);
1663
1664                 spin_lock(&pch->downl);
1665                 if (pch->chan) {
1666                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1667                                 ppp->xmit_pending = NULL;
1668                 } else {
1669                         /* channel got unregistered */
1670                         kfree_skb(skb);
1671                         ppp->xmit_pending = NULL;
1672                 }
1673                 spin_unlock(&pch->downl);
1674                 return;
1675         }
1676
1677 #ifdef CONFIG_PPP_MULTILINK
1678         /* Multilink: fragment the packet over as many links
1679            as can take the packet at the moment. */
1680         if (!ppp_mp_explode(ppp, skb))
1681                 return;
1682 #endif /* CONFIG_PPP_MULTILINK */
1683
1684         ppp->xmit_pending = NULL;
1685         kfree_skb(skb);
1686 }
1687
1688 #ifdef CONFIG_PPP_MULTILINK
1689 static bool mp_protocol_compress __read_mostly = true;
1690 module_param(mp_protocol_compress, bool, 0644);
1691 MODULE_PARM_DESC(mp_protocol_compress,
1692                  "compress protocol id in multilink fragments");
1693
1694 /*
1695  * Divide a packet to be transmitted into fragments and
1696  * send them out the individual links.
1697  */
1698 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1699 {
1700         int len, totlen;
1701         int i, bits, hdrlen, mtu;
1702         int flen;
1703         int navail, nfree, nzero;
1704         int nbigger;
1705         int totspeed;
1706         int totfree;
1707         unsigned char *p, *q;
1708         struct list_head *list;
1709         struct channel *pch;
1710         struct sk_buff *frag;
1711         struct ppp_channel *chan;
1712
1713         totspeed = 0; /*total bitrate of the bundle*/
1714         nfree = 0; /* # channels which have no packet already queued */
1715         navail = 0; /* total # of usable channels (not deregistered) */
1716         nzero = 0; /* number of channels with zero speed associated*/
1717         totfree = 0; /*total # of channels available and
1718                                   *having no queued packets before
1719                                   *starting the fragmentation*/
1720
1721         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1722         i = 0;
1723         list_for_each_entry(pch, &ppp->channels, clist) {
1724                 if (pch->chan) {
1725                         pch->avail = 1;
1726                         navail++;
1727                         pch->speed = pch->chan->speed;
1728                 } else {
1729                         pch->avail = 0;
1730                 }
1731                 if (pch->avail) {
1732                         if (skb_queue_empty(&pch->file.xq) ||
1733                                 !pch->had_frag) {
1734                                         if (pch->speed == 0)
1735                                                 nzero++;
1736                                         else
1737                                                 totspeed += pch->speed;
1738
1739                                         pch->avail = 2;
1740                                         ++nfree;
1741                                         ++totfree;
1742                                 }
1743                         if (!pch->had_frag && i < ppp->nxchan)
1744                                 ppp->nxchan = i;
1745                 }
1746                 ++i;
1747         }
1748         /*
1749          * Don't start sending this packet unless at least half of
1750          * the channels are free.  This gives much better TCP
1751          * performance if we have a lot of channels.
1752          */
1753         if (nfree == 0 || nfree < navail / 2)
1754                 return 0; /* can't take now, leave it in xmit_pending */
1755
1756         /* Do protocol field compression */
1757         p = skb->data;
1758         len = skb->len;
1759         if (*p == 0 && mp_protocol_compress) {
1760                 ++p;
1761                 --len;
1762         }
1763
1764         totlen = len;
1765         nbigger = len % nfree;
1766
1767         /* skip to the channel after the one we last used
1768            and start at that one */
1769         list = &ppp->channels;
1770         for (i = 0; i < ppp->nxchan; ++i) {
1771                 list = list->next;
1772                 if (list == &ppp->channels) {
1773                         i = 0;
1774                         break;
1775                 }
1776         }
1777
1778         /* create a fragment for each channel */
1779         bits = B;
1780         while (len > 0) {
1781                 list = list->next;
1782                 if (list == &ppp->channels) {
1783                         i = 0;
1784                         continue;
1785                 }
1786                 pch = list_entry(list, struct channel, clist);
1787                 ++i;
1788                 if (!pch->avail)
1789                         continue;
1790
1791                 /*
1792                  * Skip this channel if it has a fragment pending already and
1793                  * we haven't given a fragment to all of the free channels.
1794                  */
1795                 if (pch->avail == 1) {
1796                         if (nfree > 0)
1797                                 continue;
1798                 } else {
1799                         pch->avail = 1;
1800                 }
1801
1802                 /* check the channel's mtu and whether it is still attached. */
1803                 spin_lock(&pch->downl);
1804                 if (pch->chan == NULL) {
1805                         /* can't use this channel, it's being deregistered */
1806                         if (pch->speed == 0)
1807                                 nzero--;
1808                         else
1809                                 totspeed -= pch->speed;
1810
1811                         spin_unlock(&pch->downl);
1812                         pch->avail = 0;
1813                         totlen = len;
1814                         totfree--;
1815                         nfree--;
1816                         if (--navail == 0)
1817                                 break;
1818                         continue;
1819                 }
1820
1821                 /*
1822                 *if the channel speed is not set divide
1823                 *the packet evenly among the free channels;
1824                 *otherwise divide it according to the speed
1825                 *of the channel we are going to transmit on
1826                 */
1827                 flen = len;
1828                 if (nfree > 0) {
1829                         if (pch->speed == 0) {
1830                                 flen = len/nfree;
1831                                 if (nbigger > 0) {
1832                                         flen++;
1833                                         nbigger--;
1834                                 }
1835                         } else {
1836                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1837                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1838                                 if (nbigger > 0) {
1839                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1840                                         nbigger -= ((totfree - nzero)*pch->speed)/
1841                                                         totspeed;
1842                                 }
1843                         }
1844                         nfree--;
1845                 }
1846
1847                 /*
1848                  *check if we are on the last channel or
1849                  *we exceded the length of the data to
1850                  *fragment
1851                  */
1852                 if ((nfree <= 0) || (flen > len))
1853                         flen = len;
1854                 /*
1855                  *it is not worth to tx on slow channels:
1856                  *in that case from the resulting flen according to the
1857                  *above formula will be equal or less than zero.
1858                  *Skip the channel in this case
1859                  */
1860                 if (flen <= 0) {
1861                         pch->avail = 2;
1862                         spin_unlock(&pch->downl);
1863                         continue;
1864                 }
1865
1866                 /*
1867                  * hdrlen includes the 2-byte PPP protocol field, but the
1868                  * MTU counts only the payload excluding the protocol field.
1869                  * (RFC1661 Section 2)
1870                  */
1871                 mtu = pch->chan->mtu - (hdrlen - 2);
1872                 if (mtu < 4)
1873                         mtu = 4;
1874                 if (flen > mtu)
1875                         flen = mtu;
1876                 if (flen == len)
1877                         bits |= E;
1878                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1879                 if (!frag)
1880                         goto noskb;
1881                 q = skb_put(frag, flen + hdrlen);
1882
1883                 /* make the MP header */
1884                 put_unaligned_be16(PPP_MP, q);
1885                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1886                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1887                         q[3] = ppp->nxseq;
1888                 } else {
1889                         q[2] = bits;
1890                         q[3] = ppp->nxseq >> 16;
1891                         q[4] = ppp->nxseq >> 8;
1892                         q[5] = ppp->nxseq;
1893                 }
1894
1895                 memcpy(q + hdrlen, p, flen);
1896
1897                 /* try to send it down the channel */
1898                 chan = pch->chan;
1899                 if (!skb_queue_empty(&pch->file.xq) ||
1900                         !chan->ops->start_xmit(chan, frag))
1901                         skb_queue_tail(&pch->file.xq, frag);
1902                 pch->had_frag = 1;
1903                 p += flen;
1904                 len -= flen;
1905                 ++ppp->nxseq;
1906                 bits = 0;
1907                 spin_unlock(&pch->downl);
1908         }
1909         ppp->nxchan = i;
1910
1911         return 1;
1912
1913  noskb:
1914         spin_unlock(&pch->downl);
1915         if (ppp->debug & 1)
1916                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1917         ++ppp->dev->stats.tx_errors;
1918         ++ppp->nxseq;
1919         return 1;       /* abandon the frame */
1920 }
1921 #endif /* CONFIG_PPP_MULTILINK */
1922
1923 /* Try to send data out on a channel */
1924 static void __ppp_channel_push(struct channel *pch)
1925 {
1926         struct sk_buff *skb;
1927         struct ppp *ppp;
1928
1929         spin_lock(&pch->downl);
1930         if (pch->chan) {
1931                 while (!skb_queue_empty(&pch->file.xq)) {
1932                         skb = skb_dequeue(&pch->file.xq);
1933                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1934                                 /* put the packet back and try again later */
1935                                 skb_queue_head(&pch->file.xq, skb);
1936                                 break;
1937                         }
1938                 }
1939         } else {
1940                 /* channel got deregistered */
1941                 skb_queue_purge(&pch->file.xq);
1942         }
1943         spin_unlock(&pch->downl);
1944         /* see if there is anything from the attached unit to be sent */
1945         if (skb_queue_empty(&pch->file.xq)) {
1946                 ppp = pch->ppp;
1947                 if (ppp)
1948                         __ppp_xmit_process(ppp, NULL);
1949         }
1950 }
1951
1952 static void ppp_channel_push(struct channel *pch)
1953 {
1954         read_lock_bh(&pch->upl);
1955         if (pch->ppp) {
1956                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
1957                 __ppp_channel_push(pch);
1958                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
1959         } else {
1960                 __ppp_channel_push(pch);
1961         }
1962         read_unlock_bh(&pch->upl);
1963 }
1964
1965 /*
1966  * Receive-side routines.
1967  */
1968
1969 struct ppp_mp_skb_parm {
1970         u32             sequence;
1971         u8              BEbits;
1972 };
1973 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1974
1975 static inline void
1976 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1977 {
1978         ppp_recv_lock(ppp);
1979         if (!ppp->closing)
1980                 ppp_receive_frame(ppp, skb, pch);
1981         else
1982                 kfree_skb(skb);
1983         ppp_recv_unlock(ppp);
1984 }
1985
1986 void
1987 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1988 {
1989         struct channel *pch = chan->ppp;
1990         int proto;
1991
1992         if (!pch) {
1993                 kfree_skb(skb);
1994                 return;
1995         }
1996
1997         read_lock_bh(&pch->upl);
1998         if (!pskb_may_pull(skb, 2)) {
1999                 kfree_skb(skb);
2000                 if (pch->ppp) {
2001                         ++pch->ppp->dev->stats.rx_length_errors;
2002                         ppp_receive_error(pch->ppp);
2003                 }
2004                 goto done;
2005         }
2006
2007         proto = PPP_PROTO(skb);
2008         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2009                 /* put it on the channel queue */
2010                 skb_queue_tail(&pch->file.rq, skb);
2011                 /* drop old frames if queue too long */
2012                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2013                        (skb = skb_dequeue(&pch->file.rq)))
2014                         kfree_skb(skb);
2015                 wake_up_interruptible(&pch->file.rwait);
2016         } else {
2017                 ppp_do_recv(pch->ppp, skb, pch);
2018         }
2019
2020 done:
2021         read_unlock_bh(&pch->upl);
2022 }
2023
2024 /* Put a 0-length skb in the receive queue as an error indication */
2025 void
2026 ppp_input_error(struct ppp_channel *chan, int code)
2027 {
2028         struct channel *pch = chan->ppp;
2029         struct sk_buff *skb;
2030
2031         if (!pch)
2032                 return;
2033
2034         read_lock_bh(&pch->upl);
2035         if (pch->ppp) {
2036                 skb = alloc_skb(0, GFP_ATOMIC);
2037                 if (skb) {
2038                         skb->len = 0;           /* probably unnecessary */
2039                         skb->cb[0] = code;
2040                         ppp_do_recv(pch->ppp, skb, pch);
2041                 }
2042         }
2043         read_unlock_bh(&pch->upl);
2044 }
2045
2046 /*
2047  * We come in here to process a received frame.
2048  * The receive side of the ppp unit is locked.
2049  */
2050 static void
2051 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2052 {
2053         /* note: a 0-length skb is used as an error indication */
2054         if (skb->len > 0) {
2055                 skb_checksum_complete_unset(skb);
2056 #ifdef CONFIG_PPP_MULTILINK
2057                 /* XXX do channel-level decompression here */
2058                 if (PPP_PROTO(skb) == PPP_MP)
2059                         ppp_receive_mp_frame(ppp, skb, pch);
2060                 else
2061 #endif /* CONFIG_PPP_MULTILINK */
2062                         ppp_receive_nonmp_frame(ppp, skb);
2063         } else {
2064                 kfree_skb(skb);
2065                 ppp_receive_error(ppp);
2066         }
2067 }
2068
2069 static void
2070 ppp_receive_error(struct ppp *ppp)
2071 {
2072         ++ppp->dev->stats.rx_errors;
2073         if (ppp->vj)
2074                 slhc_toss(ppp->vj);
2075 }
2076
2077 static void
2078 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2079 {
2080         struct sk_buff *ns;
2081         int proto, len, npi;
2082
2083         /*
2084          * Decompress the frame, if compressed.
2085          * Note that some decompressors need to see uncompressed frames
2086          * that come in as well as compressed frames.
2087          */
2088         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2089             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2090                 skb = ppp_decompress_frame(ppp, skb);
2091
2092         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2093                 goto err;
2094
2095         proto = PPP_PROTO(skb);
2096         switch (proto) {
2097         case PPP_VJC_COMP:
2098                 /* decompress VJ compressed packets */
2099                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2100                         goto err;
2101
2102                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2103                         /* copy to a new sk_buff with more tailroom */
2104                         ns = dev_alloc_skb(skb->len + 128);
2105                         if (!ns) {
2106                                 netdev_err(ppp->dev, "PPP: no memory "
2107                                            "(VJ decomp)\n");
2108                                 goto err;
2109                         }
2110                         skb_reserve(ns, 2);
2111                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2112                         consume_skb(skb);
2113                         skb = ns;
2114                 }
2115                 else
2116                         skb->ip_summed = CHECKSUM_NONE;
2117
2118                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2119                 if (len <= 0) {
2120                         netdev_printk(KERN_DEBUG, ppp->dev,
2121                                       "PPP: VJ decompression error\n");
2122                         goto err;
2123                 }
2124                 len += 2;
2125                 if (len > skb->len)
2126                         skb_put(skb, len - skb->len);
2127                 else if (len < skb->len)
2128                         skb_trim(skb, len);
2129                 proto = PPP_IP;
2130                 break;
2131
2132         case PPP_VJC_UNCOMP:
2133                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2134                         goto err;
2135
2136                 /* Until we fix the decompressor need to make sure
2137                  * data portion is linear.
2138                  */
2139                 if (!pskb_may_pull(skb, skb->len))
2140                         goto err;
2141
2142                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2143                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2144                         goto err;
2145                 }
2146                 proto = PPP_IP;
2147                 break;
2148
2149         case PPP_CCP:
2150                 ppp_ccp_peek(ppp, skb, 1);
2151                 break;
2152         }
2153
2154         ++ppp->stats64.rx_packets;
2155         ppp->stats64.rx_bytes += skb->len - 2;
2156
2157         npi = proto_to_npindex(proto);
2158         if (npi < 0) {
2159                 /* control or unknown frame - pass it to pppd */
2160                 skb_queue_tail(&ppp->file.rq, skb);
2161                 /* limit queue length by dropping old frames */
2162                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2163                        (skb = skb_dequeue(&ppp->file.rq)))
2164                         kfree_skb(skb);
2165                 /* wake up any process polling or blocking on read */
2166                 wake_up_interruptible(&ppp->file.rwait);
2167
2168         } else {
2169                 /* network protocol frame - give it to the kernel */
2170
2171 #ifdef CONFIG_PPP_FILTER
2172                 /* check if the packet passes the pass and active filters */
2173                 /* the filter instructions are constructed assuming
2174                    a four-byte PPP header on each packet */
2175                 if (ppp->pass_filter || ppp->active_filter) {
2176                         if (skb_unclone(skb, GFP_ATOMIC))
2177                                 goto err;
2178
2179                         *(u8 *)skb_push(skb, 2) = 0;
2180                         if (ppp->pass_filter &&
2181                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2182                                 if (ppp->debug & 1)
2183                                         netdev_printk(KERN_DEBUG, ppp->dev,
2184                                                       "PPP: inbound frame "
2185                                                       "not passed\n");
2186                                 kfree_skb(skb);
2187                                 return;
2188                         }
2189                         if (!(ppp->active_filter &&
2190                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2191                                 ppp->last_recv = jiffies;
2192                         __skb_pull(skb, 2);
2193                 } else
2194 #endif /* CONFIG_PPP_FILTER */
2195                         ppp->last_recv = jiffies;
2196
2197                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2198                     ppp->npmode[npi] != NPMODE_PASS) {
2199                         kfree_skb(skb);
2200                 } else {
2201                         /* chop off protocol */
2202                         skb_pull_rcsum(skb, 2);
2203                         skb->dev = ppp->dev;
2204                         skb->protocol = htons(npindex_to_ethertype[npi]);
2205                         skb_reset_mac_header(skb);
2206                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2207                                                       dev_net(ppp->dev)));
2208                         netif_rx(skb);
2209                 }
2210         }
2211         return;
2212
2213  err:
2214         kfree_skb(skb);
2215         ppp_receive_error(ppp);
2216 }
2217
2218 static struct sk_buff *
2219 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2220 {
2221         int proto = PPP_PROTO(skb);
2222         struct sk_buff *ns;
2223         int len;
2224
2225         /* Until we fix all the decompressor's need to make sure
2226          * data portion is linear.
2227          */
2228         if (!pskb_may_pull(skb, skb->len))
2229                 goto err;
2230
2231         if (proto == PPP_COMP) {
2232                 int obuff_size;
2233
2234                 switch(ppp->rcomp->compress_proto) {
2235                 case CI_MPPE:
2236                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2237                         break;
2238                 default:
2239                         obuff_size = ppp->mru + PPP_HDRLEN;
2240                         break;
2241                 }
2242
2243                 ns = dev_alloc_skb(obuff_size);
2244                 if (!ns) {
2245                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2246                                    "no memory\n");
2247                         goto err;
2248                 }
2249                 /* the decompressor still expects the A/C bytes in the hdr */
2250                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2251                                 skb->len + 2, ns->data, obuff_size);
2252                 if (len < 0) {
2253                         /* Pass the compressed frame to pppd as an
2254                            error indication. */
2255                         if (len == DECOMP_FATALERROR)
2256                                 ppp->rstate |= SC_DC_FERROR;
2257                         kfree_skb(ns);
2258                         goto err;
2259                 }
2260
2261                 consume_skb(skb);
2262                 skb = ns;
2263                 skb_put(skb, len);
2264                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2265
2266         } else {
2267                 /* Uncompressed frame - pass to decompressor so it
2268                    can update its dictionary if necessary. */
2269                 if (ppp->rcomp->incomp)
2270                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2271                                            skb->len + 2);
2272         }
2273
2274         return skb;
2275
2276  err:
2277         ppp->rstate |= SC_DC_ERROR;
2278         ppp_receive_error(ppp);
2279         return skb;
2280 }
2281
2282 #ifdef CONFIG_PPP_MULTILINK
2283 /*
2284  * Receive a multilink frame.
2285  * We put it on the reconstruction queue and then pull off
2286  * as many completed frames as we can.
2287  */
2288 static void
2289 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2290 {
2291         u32 mask, seq;
2292         struct channel *ch;
2293         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2294
2295         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2296                 goto err;               /* no good, throw it away */
2297
2298         /* Decode sequence number and begin/end bits */
2299         if (ppp->flags & SC_MP_SHORTSEQ) {
2300                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2301                 mask = 0xfff;
2302         } else {
2303                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2304                 mask = 0xffffff;
2305         }
2306         PPP_MP_CB(skb)->BEbits = skb->data[2];
2307         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2308
2309         /*
2310          * Do protocol ID decompression on the first fragment of each packet.
2311          */
2312         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2313                 *(u8 *)skb_push(skb, 1) = 0;
2314
2315         /*
2316          * Expand sequence number to 32 bits, making it as close
2317          * as possible to ppp->minseq.
2318          */
2319         seq |= ppp->minseq & ~mask;
2320         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2321                 seq += mask + 1;
2322         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2323                 seq -= mask + 1;        /* should never happen */
2324         PPP_MP_CB(skb)->sequence = seq;
2325         pch->lastseq = seq;
2326
2327         /*
2328          * If this packet comes before the next one we were expecting,
2329          * drop it.
2330          */
2331         if (seq_before(seq, ppp->nextseq)) {
2332                 kfree_skb(skb);
2333                 ++ppp->dev->stats.rx_dropped;
2334                 ppp_receive_error(ppp);
2335                 return;
2336         }
2337
2338         /*
2339          * Reevaluate minseq, the minimum over all channels of the
2340          * last sequence number received on each channel.  Because of
2341          * the increasing sequence number rule, we know that any fragment
2342          * before `minseq' which hasn't arrived is never going to arrive.
2343          * The list of channels can't change because we have the receive
2344          * side of the ppp unit locked.
2345          */
2346         list_for_each_entry(ch, &ppp->channels, clist) {
2347                 if (seq_before(ch->lastseq, seq))
2348                         seq = ch->lastseq;
2349         }
2350         if (seq_before(ppp->minseq, seq))
2351                 ppp->minseq = seq;
2352
2353         /* Put the fragment on the reconstruction queue */
2354         ppp_mp_insert(ppp, skb);
2355
2356         /* If the queue is getting long, don't wait any longer for packets
2357            before the start of the queue. */
2358         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2359                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2360                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2361                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2362         }
2363
2364         /* Pull completed packets off the queue and receive them. */
2365         while ((skb = ppp_mp_reconstruct(ppp))) {
2366                 if (pskb_may_pull(skb, 2))
2367                         ppp_receive_nonmp_frame(ppp, skb);
2368                 else {
2369                         ++ppp->dev->stats.rx_length_errors;
2370                         kfree_skb(skb);
2371                         ppp_receive_error(ppp);
2372                 }
2373         }
2374
2375         return;
2376
2377  err:
2378         kfree_skb(skb);
2379         ppp_receive_error(ppp);
2380 }
2381
2382 /*
2383  * Insert a fragment on the MP reconstruction queue.
2384  * The queue is ordered by increasing sequence number.
2385  */
2386 static void
2387 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2388 {
2389         struct sk_buff *p;
2390         struct sk_buff_head *list = &ppp->mrq;
2391         u32 seq = PPP_MP_CB(skb)->sequence;
2392
2393         /* N.B. we don't need to lock the list lock because we have the
2394            ppp unit receive-side lock. */
2395         skb_queue_walk(list, p) {
2396                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2397                         break;
2398         }
2399         __skb_queue_before(list, p, skb);
2400 }
2401
2402 /*
2403  * Reconstruct a packet from the MP fragment queue.
2404  * We go through increasing sequence numbers until we find a
2405  * complete packet, or we get to the sequence number for a fragment
2406  * which hasn't arrived but might still do so.
2407  */
2408 static struct sk_buff *
2409 ppp_mp_reconstruct(struct ppp *ppp)
2410 {
2411         u32 seq = ppp->nextseq;
2412         u32 minseq = ppp->minseq;
2413         struct sk_buff_head *list = &ppp->mrq;
2414         struct sk_buff *p, *tmp;
2415         struct sk_buff *head, *tail;
2416         struct sk_buff *skb = NULL;
2417         int lost = 0, len = 0;
2418
2419         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2420                 return NULL;
2421         head = list->next;
2422         tail = NULL;
2423         skb_queue_walk_safe(list, p, tmp) {
2424         again:
2425                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2426                         /* this can't happen, anyway ignore the skb */
2427                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2428                                    "seq %u < %u\n",
2429                                    PPP_MP_CB(p)->sequence, seq);
2430                         __skb_unlink(p, list);
2431                         kfree_skb(p);
2432                         continue;
2433                 }
2434                 if (PPP_MP_CB(p)->sequence != seq) {
2435                         u32 oldseq;
2436                         /* Fragment `seq' is missing.  If it is after
2437                            minseq, it might arrive later, so stop here. */
2438                         if (seq_after(seq, minseq))
2439                                 break;
2440                         /* Fragment `seq' is lost, keep going. */
2441                         lost = 1;
2442                         oldseq = seq;
2443                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2444                                 minseq + 1: PPP_MP_CB(p)->sequence;
2445
2446                         if (ppp->debug & 1)
2447                                 netdev_printk(KERN_DEBUG, ppp->dev,
2448                                               "lost frag %u..%u\n",
2449                                               oldseq, seq-1);
2450
2451                         goto again;
2452                 }
2453
2454                 /*
2455                  * At this point we know that all the fragments from
2456                  * ppp->nextseq to seq are either present or lost.
2457                  * Also, there are no complete packets in the queue
2458                  * that have no missing fragments and end before this
2459                  * fragment.
2460                  */
2461
2462                 /* B bit set indicates this fragment starts a packet */
2463                 if (PPP_MP_CB(p)->BEbits & B) {
2464                         head = p;
2465                         lost = 0;
2466                         len = 0;
2467                 }
2468
2469                 len += p->len;
2470
2471                 /* Got a complete packet yet? */
2472                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2473                     (PPP_MP_CB(head)->BEbits & B)) {
2474                         if (len > ppp->mrru + 2) {
2475                                 ++ppp->dev->stats.rx_length_errors;
2476                                 netdev_printk(KERN_DEBUG, ppp->dev,
2477                                               "PPP: reconstructed packet"
2478                                               " is too long (%d)\n", len);
2479                         } else {
2480                                 tail = p;
2481                                 break;
2482                         }
2483                         ppp->nextseq = seq + 1;
2484                 }
2485
2486                 /*
2487                  * If this is the ending fragment of a packet,
2488                  * and we haven't found a complete valid packet yet,
2489                  * we can discard up to and including this fragment.
2490                  */
2491                 if (PPP_MP_CB(p)->BEbits & E) {
2492                         struct sk_buff *tmp2;
2493
2494                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2495                                 if (ppp->debug & 1)
2496                                         netdev_printk(KERN_DEBUG, ppp->dev,
2497                                                       "discarding frag %u\n",
2498                                                       PPP_MP_CB(p)->sequence);
2499                                 __skb_unlink(p, list);
2500                                 kfree_skb(p);
2501                         }
2502                         head = skb_peek(list);
2503                         if (!head)
2504                                 break;
2505                 }
2506                 ++seq;
2507         }
2508
2509         /* If we have a complete packet, copy it all into one skb. */
2510         if (tail != NULL) {
2511                 /* If we have discarded any fragments,
2512                    signal a receive error. */
2513                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2514                         skb_queue_walk_safe(list, p, tmp) {
2515                                 if (p == head)
2516                                         break;
2517                                 if (ppp->debug & 1)
2518                                         netdev_printk(KERN_DEBUG, ppp->dev,
2519                                                       "discarding frag %u\n",
2520                                                       PPP_MP_CB(p)->sequence);
2521                                 __skb_unlink(p, list);
2522                                 kfree_skb(p);
2523                         }
2524
2525                         if (ppp->debug & 1)
2526                                 netdev_printk(KERN_DEBUG, ppp->dev,
2527                                               "  missed pkts %u..%u\n",
2528                                               ppp->nextseq,
2529                                               PPP_MP_CB(head)->sequence-1);
2530                         ++ppp->dev->stats.rx_dropped;
2531                         ppp_receive_error(ppp);
2532                 }
2533
2534                 skb = head;
2535                 if (head != tail) {
2536                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2537                         p = skb_queue_next(list, head);
2538                         __skb_unlink(skb, list);
2539                         skb_queue_walk_from_safe(list, p, tmp) {
2540                                 __skb_unlink(p, list);
2541                                 *fragpp = p;
2542                                 p->next = NULL;
2543                                 fragpp = &p->next;
2544
2545                                 skb->len += p->len;
2546                                 skb->data_len += p->len;
2547                                 skb->truesize += p->truesize;
2548
2549                                 if (p == tail)
2550                                         break;
2551                         }
2552                 } else {
2553                         __skb_unlink(skb, list);
2554                 }
2555
2556                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2557         }
2558
2559         return skb;
2560 }
2561 #endif /* CONFIG_PPP_MULTILINK */
2562
2563 /*
2564  * Channel interface.
2565  */
2566
2567 /* Create a new, unattached ppp channel. */
2568 int ppp_register_channel(struct ppp_channel *chan)
2569 {
2570         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2571 }
2572
2573 /* Create a new, unattached ppp channel for specified net. */
2574 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2575 {
2576         struct channel *pch;
2577         struct ppp_net *pn;
2578
2579         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2580         if (!pch)
2581                 return -ENOMEM;
2582
2583         pn = ppp_pernet(net);
2584
2585         pch->ppp = NULL;
2586         pch->chan = chan;
2587         pch->chan_net = get_net(net);
2588         chan->ppp = pch;
2589         init_ppp_file(&pch->file, CHANNEL);
2590         pch->file.hdrlen = chan->hdrlen;
2591 #ifdef CONFIG_PPP_MULTILINK
2592         pch->lastseq = -1;
2593 #endif /* CONFIG_PPP_MULTILINK */
2594         init_rwsem(&pch->chan_sem);
2595         spin_lock_init(&pch->downl);
2596         rwlock_init(&pch->upl);
2597
2598         spin_lock_bh(&pn->all_channels_lock);
2599         pch->file.index = ++pn->last_channel_index;
2600         list_add(&pch->list, &pn->new_channels);
2601         atomic_inc(&channel_count);
2602         spin_unlock_bh(&pn->all_channels_lock);
2603
2604         return 0;
2605 }
2606
2607 /*
2608  * Return the index of a channel.
2609  */
2610 int ppp_channel_index(struct ppp_channel *chan)
2611 {
2612         struct channel *pch = chan->ppp;
2613
2614         if (pch)
2615                 return pch->file.index;
2616         return -1;
2617 }
2618
2619 /*
2620  * Return the PPP unit number to which a channel is connected.
2621  */
2622 int ppp_unit_number(struct ppp_channel *chan)
2623 {
2624         struct channel *pch = chan->ppp;
2625         int unit = -1;
2626
2627         if (pch) {
2628                 read_lock_bh(&pch->upl);
2629                 if (pch->ppp)
2630                         unit = pch->ppp->file.index;
2631                 read_unlock_bh(&pch->upl);
2632         }
2633         return unit;
2634 }
2635
2636 /*
2637  * Return the PPP device interface name of a channel.
2638  */
2639 char *ppp_dev_name(struct ppp_channel *chan)
2640 {
2641         struct channel *pch = chan->ppp;
2642         char *name = NULL;
2643
2644         if (pch) {
2645                 read_lock_bh(&pch->upl);
2646                 if (pch->ppp && pch->ppp->dev)
2647                         name = pch->ppp->dev->name;
2648                 read_unlock_bh(&pch->upl);
2649         }
2650         return name;
2651 }
2652
2653
2654 /*
2655  * Disconnect a channel from the generic layer.
2656  * This must be called in process context.
2657  */
2658 void
2659 ppp_unregister_channel(struct ppp_channel *chan)
2660 {
2661         struct channel *pch = chan->ppp;
2662         struct ppp_net *pn;
2663
2664         if (!pch)
2665                 return;         /* should never happen */
2666
2667         chan->ppp = NULL;
2668
2669         /*
2670          * This ensures that we have returned from any calls into the
2671          * the channel's start_xmit or ioctl routine before we proceed.
2672          */
2673         down_write(&pch->chan_sem);
2674         spin_lock_bh(&pch->downl);
2675         pch->chan = NULL;
2676         spin_unlock_bh(&pch->downl);
2677         up_write(&pch->chan_sem);
2678         ppp_disconnect_channel(pch);
2679
2680         pn = ppp_pernet(pch->chan_net);
2681         spin_lock_bh(&pn->all_channels_lock);
2682         list_del(&pch->list);
2683         spin_unlock_bh(&pn->all_channels_lock);
2684
2685         pch->file.dead = 1;
2686         wake_up_interruptible(&pch->file.rwait);
2687         if (refcount_dec_and_test(&pch->file.refcnt))
2688                 ppp_destroy_channel(pch);
2689 }
2690
2691 /*
2692  * Callback from a channel when it can accept more to transmit.
2693  * This should be called at BH/softirq level, not interrupt level.
2694  */
2695 void
2696 ppp_output_wakeup(struct ppp_channel *chan)
2697 {
2698         struct channel *pch = chan->ppp;
2699
2700         if (!pch)
2701                 return;
2702         ppp_channel_push(pch);
2703 }
2704
2705 /*
2706  * Compression control.
2707  */
2708
2709 /* Process the PPPIOCSCOMPRESS ioctl. */
2710 static int
2711 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2712 {
2713         int err;
2714         struct compressor *cp, *ocomp;
2715         struct ppp_option_data data;
2716         void *state, *ostate;
2717         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2718
2719         err = -EFAULT;
2720         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2721                 goto out;
2722         if (data.length > CCP_MAX_OPTION_LENGTH)
2723                 goto out;
2724         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2725                 goto out;
2726
2727         err = -EINVAL;
2728         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2729                 goto out;
2730
2731         cp = try_then_request_module(
2732                 find_compressor(ccp_option[0]),
2733                 "ppp-compress-%d", ccp_option[0]);
2734         if (!cp)
2735                 goto out;
2736
2737         err = -ENOBUFS;
2738         if (data.transmit) {
2739                 state = cp->comp_alloc(ccp_option, data.length);
2740                 if (state) {
2741                         ppp_xmit_lock(ppp);
2742                         ppp->xstate &= ~SC_COMP_RUN;
2743                         ocomp = ppp->xcomp;
2744                         ostate = ppp->xc_state;
2745                         ppp->xcomp = cp;
2746                         ppp->xc_state = state;
2747                         ppp_xmit_unlock(ppp);
2748                         if (ostate) {
2749                                 ocomp->comp_free(ostate);
2750                                 module_put(ocomp->owner);
2751                         }
2752                         err = 0;
2753                 } else
2754                         module_put(cp->owner);
2755
2756         } else {
2757                 state = cp->decomp_alloc(ccp_option, data.length);
2758                 if (state) {
2759                         ppp_recv_lock(ppp);
2760                         ppp->rstate &= ~SC_DECOMP_RUN;
2761                         ocomp = ppp->rcomp;
2762                         ostate = ppp->rc_state;
2763                         ppp->rcomp = cp;
2764                         ppp->rc_state = state;
2765                         ppp_recv_unlock(ppp);
2766                         if (ostate) {
2767                                 ocomp->decomp_free(ostate);
2768                                 module_put(ocomp->owner);
2769                         }
2770                         err = 0;
2771                 } else
2772                         module_put(cp->owner);
2773         }
2774
2775  out:
2776         return err;
2777 }
2778
2779 /*
2780  * Look at a CCP packet and update our state accordingly.
2781  * We assume the caller has the xmit or recv path locked.
2782  */
2783 static void
2784 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2785 {
2786         unsigned char *dp;
2787         int len;
2788
2789         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2790                 return; /* no header */
2791         dp = skb->data + 2;
2792
2793         switch (CCP_CODE(dp)) {
2794         case CCP_CONFREQ:
2795
2796                 /* A ConfReq starts negotiation of compression
2797                  * in one direction of transmission,
2798                  * and hence brings it down...but which way?
2799                  *
2800                  * Remember:
2801                  * A ConfReq indicates what the sender would like to receive
2802                  */
2803                 if(inbound)
2804                         /* He is proposing what I should send */
2805                         ppp->xstate &= ~SC_COMP_RUN;
2806                 else
2807                         /* I am proposing to what he should send */
2808                         ppp->rstate &= ~SC_DECOMP_RUN;
2809
2810                 break;
2811
2812         case CCP_TERMREQ:
2813         case CCP_TERMACK:
2814                 /*
2815                  * CCP is going down, both directions of transmission
2816                  */
2817                 ppp->rstate &= ~SC_DECOMP_RUN;
2818                 ppp->xstate &= ~SC_COMP_RUN;
2819                 break;
2820
2821         case CCP_CONFACK:
2822                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2823                         break;
2824                 len = CCP_LENGTH(dp);
2825                 if (!pskb_may_pull(skb, len + 2))
2826                         return;         /* too short */
2827                 dp += CCP_HDRLEN;
2828                 len -= CCP_HDRLEN;
2829                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2830                         break;
2831                 if (inbound) {
2832                         /* we will start receiving compressed packets */
2833                         if (!ppp->rc_state)
2834                                 break;
2835                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2836                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2837                                 ppp->rstate |= SC_DECOMP_RUN;
2838                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2839                         }
2840                 } else {
2841                         /* we will soon start sending compressed packets */
2842                         if (!ppp->xc_state)
2843                                 break;
2844                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2845                                         ppp->file.index, 0, ppp->debug))
2846                                 ppp->xstate |= SC_COMP_RUN;
2847                 }
2848                 break;
2849
2850         case CCP_RESETACK:
2851                 /* reset the [de]compressor */
2852                 if ((ppp->flags & SC_CCP_UP) == 0)
2853                         break;
2854                 if (inbound) {
2855                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2856                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2857                                 ppp->rstate &= ~SC_DC_ERROR;
2858                         }
2859                 } else {
2860                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2861                                 ppp->xcomp->comp_reset(ppp->xc_state);
2862                 }
2863                 break;
2864         }
2865 }
2866
2867 /* Free up compression resources. */
2868 static void
2869 ppp_ccp_closed(struct ppp *ppp)
2870 {
2871         void *xstate, *rstate;
2872         struct compressor *xcomp, *rcomp;
2873
2874         ppp_lock(ppp);
2875         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2876         ppp->xstate = 0;
2877         xcomp = ppp->xcomp;
2878         xstate = ppp->xc_state;
2879         ppp->xc_state = NULL;
2880         ppp->rstate = 0;
2881         rcomp = ppp->rcomp;
2882         rstate = ppp->rc_state;
2883         ppp->rc_state = NULL;
2884         ppp_unlock(ppp);
2885
2886         if (xstate) {
2887                 xcomp->comp_free(xstate);
2888                 module_put(xcomp->owner);
2889         }
2890         if (rstate) {
2891                 rcomp->decomp_free(rstate);
2892                 module_put(rcomp->owner);
2893         }
2894 }
2895
2896 /* List of compressors. */
2897 static LIST_HEAD(compressor_list);
2898 static DEFINE_SPINLOCK(compressor_list_lock);
2899
2900 struct compressor_entry {
2901         struct list_head list;
2902         struct compressor *comp;
2903 };
2904
2905 static struct compressor_entry *
2906 find_comp_entry(int proto)
2907 {
2908         struct compressor_entry *ce;
2909
2910         list_for_each_entry(ce, &compressor_list, list) {
2911                 if (ce->comp->compress_proto == proto)
2912                         return ce;
2913         }
2914         return NULL;
2915 }
2916
2917 /* Register a compressor */
2918 int
2919 ppp_register_compressor(struct compressor *cp)
2920 {
2921         struct compressor_entry *ce;
2922         int ret;
2923         spin_lock(&compressor_list_lock);
2924         ret = -EEXIST;
2925         if (find_comp_entry(cp->compress_proto))
2926                 goto out;
2927         ret = -ENOMEM;
2928         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2929         if (!ce)
2930                 goto out;
2931         ret = 0;
2932         ce->comp = cp;
2933         list_add(&ce->list, &compressor_list);
2934  out:
2935         spin_unlock(&compressor_list_lock);
2936         return ret;
2937 }
2938
2939 /* Unregister a compressor */
2940 void
2941 ppp_unregister_compressor(struct compressor *cp)
2942 {
2943         struct compressor_entry *ce;
2944
2945         spin_lock(&compressor_list_lock);
2946         ce = find_comp_entry(cp->compress_proto);
2947         if (ce && ce->comp == cp) {
2948                 list_del(&ce->list);
2949                 kfree(ce);
2950         }
2951         spin_unlock(&compressor_list_lock);
2952 }
2953
2954 /* Find a compressor. */
2955 static struct compressor *
2956 find_compressor(int type)
2957 {
2958         struct compressor_entry *ce;
2959         struct compressor *cp = NULL;
2960
2961         spin_lock(&compressor_list_lock);
2962         ce = find_comp_entry(type);
2963         if (ce) {
2964                 cp = ce->comp;
2965                 if (!try_module_get(cp->owner))
2966                         cp = NULL;
2967         }
2968         spin_unlock(&compressor_list_lock);
2969         return cp;
2970 }
2971
2972 /*
2973  * Miscelleneous stuff.
2974  */
2975
2976 static void
2977 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2978 {
2979         struct slcompress *vj = ppp->vj;
2980
2981         memset(st, 0, sizeof(*st));
2982         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2983         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2984         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2985         st->p.ppp_opackets = ppp->stats64.tx_packets;
2986         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2987         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2988         if (!vj)
2989                 return;
2990         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2991         st->vj.vjs_compressed = vj->sls_o_compressed;
2992         st->vj.vjs_searches = vj->sls_o_searches;
2993         st->vj.vjs_misses = vj->sls_o_misses;
2994         st->vj.vjs_errorin = vj->sls_i_error;
2995         st->vj.vjs_tossed = vj->sls_i_tossed;
2996         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2997         st->vj.vjs_compressedin = vj->sls_i_compressed;
2998 }
2999
3000 /*
3001  * Stuff for handling the lists of ppp units and channels
3002  * and for initialization.
3003  */
3004
3005 /*
3006  * Create a new ppp interface unit.  Fails if it can't allocate memory
3007  * or if there is already a unit with the requested number.
3008  * unit == -1 means allocate a new number.
3009  */
3010 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3011 {
3012         struct ppp_config conf = {
3013                 .file = file,
3014                 .unit = *unit,
3015                 .ifname_is_set = false,
3016         };
3017         struct net_device *dev;
3018         struct ppp *ppp;
3019         int err;
3020
3021         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3022         if (!dev) {
3023                 err = -ENOMEM;
3024                 goto err;
3025         }
3026         dev_net_set(dev, net);
3027         dev->rtnl_link_ops = &ppp_link_ops;
3028
3029         rtnl_lock();
3030
3031         err = ppp_dev_configure(net, dev, &conf);
3032         if (err < 0)
3033                 goto err_dev;
3034         ppp = netdev_priv(dev);
3035         *unit = ppp->file.index;
3036
3037         rtnl_unlock();
3038
3039         return 0;
3040
3041 err_dev:
3042         rtnl_unlock();
3043         free_netdev(dev);
3044 err:
3045         return err;
3046 }
3047
3048 /*
3049  * Initialize a ppp_file structure.
3050  */
3051 static void
3052 init_ppp_file(struct ppp_file *pf, int kind)
3053 {
3054         pf->kind = kind;
3055         skb_queue_head_init(&pf->xq);
3056         skb_queue_head_init(&pf->rq);
3057         refcount_set(&pf->refcnt, 1);
3058         init_waitqueue_head(&pf->rwait);
3059 }
3060
3061 /*
3062  * Free the memory used by a ppp unit.  This is only called once
3063  * there are no channels connected to the unit and no file structs
3064  * that reference the unit.
3065  */
3066 static void ppp_destroy_interface(struct ppp *ppp)
3067 {
3068         atomic_dec(&ppp_unit_count);
3069
3070         if (!ppp->file.dead || ppp->n_channels) {
3071                 /* "can't happen" */
3072                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3073                            "but dead=%d n_channels=%d !\n",
3074                            ppp, ppp->file.dead, ppp->n_channels);
3075                 return;
3076         }
3077
3078         ppp_ccp_closed(ppp);
3079         if (ppp->vj) {
3080                 slhc_free(ppp->vj);
3081                 ppp->vj = NULL;
3082         }
3083         skb_queue_purge(&ppp->file.xq);
3084         skb_queue_purge(&ppp->file.rq);
3085 #ifdef CONFIG_PPP_MULTILINK
3086         skb_queue_purge(&ppp->mrq);
3087 #endif /* CONFIG_PPP_MULTILINK */
3088 #ifdef CONFIG_PPP_FILTER
3089         if (ppp->pass_filter) {
3090                 bpf_prog_destroy(ppp->pass_filter);
3091                 ppp->pass_filter = NULL;
3092         }
3093
3094         if (ppp->active_filter) {
3095                 bpf_prog_destroy(ppp->active_filter);
3096                 ppp->active_filter = NULL;
3097         }
3098 #endif /* CONFIG_PPP_FILTER */
3099
3100         kfree_skb(ppp->xmit_pending);
3101         free_percpu(ppp->xmit_recursion);
3102
3103         free_netdev(ppp->dev);
3104 }
3105
3106 /*
3107  * Locate an existing ppp unit.
3108  * The caller should have locked the all_ppp_mutex.
3109  */
3110 static struct ppp *
3111 ppp_find_unit(struct ppp_net *pn, int unit)
3112 {
3113         return unit_find(&pn->units_idr, unit);
3114 }
3115
3116 /*
3117  * Locate an existing ppp channel.
3118  * The caller should have locked the all_channels_lock.
3119  * First we look in the new_channels list, then in the
3120  * all_channels list.  If found in the new_channels list,
3121  * we move it to the all_channels list.  This is for speed
3122  * when we have a lot of channels in use.
3123  */
3124 static struct channel *
3125 ppp_find_channel(struct ppp_net *pn, int unit)
3126 {
3127         struct channel *pch;
3128
3129         list_for_each_entry(pch, &pn->new_channels, list) {
3130                 if (pch->file.index == unit) {
3131                         list_move(&pch->list, &pn->all_channels);
3132                         return pch;
3133                 }
3134         }
3135
3136         list_for_each_entry(pch, &pn->all_channels, list) {
3137                 if (pch->file.index == unit)
3138                         return pch;
3139         }
3140
3141         return NULL;
3142 }
3143
3144 /*
3145  * Connect a PPP channel to a PPP interface unit.
3146  */
3147 static int
3148 ppp_connect_channel(struct channel *pch, int unit)
3149 {
3150         struct ppp *ppp;
3151         struct ppp_net *pn;
3152         int ret = -ENXIO;
3153         int hdrlen;
3154
3155         pn = ppp_pernet(pch->chan_net);
3156
3157         mutex_lock(&pn->all_ppp_mutex);
3158         ppp = ppp_find_unit(pn, unit);
3159         if (!ppp)
3160                 goto out;
3161         write_lock_bh(&pch->upl);
3162         ret = -EINVAL;
3163         if (pch->ppp)
3164                 goto outl;
3165
3166         ppp_lock(ppp);
3167         spin_lock_bh(&pch->downl);
3168         if (!pch->chan) {
3169                 /* Don't connect unregistered channels */
3170                 spin_unlock_bh(&pch->downl);
3171                 ppp_unlock(ppp);
3172                 ret = -ENOTCONN;
3173                 goto outl;
3174         }
3175         spin_unlock_bh(&pch->downl);
3176         if (pch->file.hdrlen > ppp->file.hdrlen)
3177                 ppp->file.hdrlen = pch->file.hdrlen;
3178         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3179         if (hdrlen > ppp->dev->hard_header_len)
3180                 ppp->dev->hard_header_len = hdrlen;
3181         list_add_tail(&pch->clist, &ppp->channels);
3182         ++ppp->n_channels;
3183         pch->ppp = ppp;
3184         refcount_inc(&ppp->file.refcnt);
3185         ppp_unlock(ppp);
3186         ret = 0;
3187
3188  outl:
3189         write_unlock_bh(&pch->upl);
3190  out:
3191         mutex_unlock(&pn->all_ppp_mutex);
3192         return ret;
3193 }
3194
3195 /*
3196  * Disconnect a channel from its ppp unit.
3197  */
3198 static int
3199 ppp_disconnect_channel(struct channel *pch)
3200 {
3201         struct ppp *ppp;
3202         int err = -EINVAL;
3203
3204         write_lock_bh(&pch->upl);
3205         ppp = pch->ppp;
3206         pch->ppp = NULL;
3207         write_unlock_bh(&pch->upl);
3208         if (ppp) {
3209                 /* remove it from the ppp unit's list */
3210                 ppp_lock(ppp);
3211                 list_del(&pch->clist);
3212                 if (--ppp->n_channels == 0)
3213                         wake_up_interruptible(&ppp->file.rwait);
3214                 ppp_unlock(ppp);
3215                 if (refcount_dec_and_test(&ppp->file.refcnt))
3216                         ppp_destroy_interface(ppp);
3217                 err = 0;
3218         }
3219         return err;
3220 }
3221
3222 /*
3223  * Free up the resources used by a ppp channel.
3224  */
3225 static void ppp_destroy_channel(struct channel *pch)
3226 {
3227         put_net(pch->chan_net);
3228         pch->chan_net = NULL;
3229
3230         atomic_dec(&channel_count);
3231
3232         if (!pch->file.dead) {
3233                 /* "can't happen" */
3234                 pr_err("ppp: destroying undead channel %p !\n", pch);
3235                 return;
3236         }
3237         skb_queue_purge(&pch->file.xq);
3238         skb_queue_purge(&pch->file.rq);
3239         kfree(pch);
3240 }
3241
3242 static void __exit ppp_cleanup(void)
3243 {
3244         /* should never happen */
3245         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3246                 pr_err("PPP: removing module but units remain!\n");
3247         rtnl_link_unregister(&ppp_link_ops);
3248         unregister_chrdev(PPP_MAJOR, "ppp");
3249         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3250         class_destroy(ppp_class);
3251         unregister_pernet_device(&ppp_net_ops);
3252 }
3253
3254 /*
3255  * Units handling. Caller must protect concurrent access
3256  * by holding all_ppp_mutex
3257  */
3258
3259 /* associate pointer with specified number */
3260 static int unit_set(struct idr *p, void *ptr, int n)
3261 {
3262         int unit;
3263
3264         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3265         if (unit == -ENOSPC)
3266                 unit = -EINVAL;
3267         return unit;
3268 }
3269
3270 /* get new free unit number and associate pointer with it */
3271 static int unit_get(struct idr *p, void *ptr, int min)
3272 {
3273         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3274 }
3275
3276 /* put unit number back to a pool */
3277 static void unit_put(struct idr *p, int n)
3278 {
3279         idr_remove(p, n);
3280 }
3281
3282 /* get pointer associated with the number */
3283 static void *unit_find(struct idr *p, int n)
3284 {
3285         return idr_find(p, n);
3286 }
3287
3288 /* Module/initialization stuff */
3289
3290 module_init(ppp_init);
3291 module_exit(ppp_cleanup);
3292
3293 EXPORT_SYMBOL(ppp_register_net_channel);
3294 EXPORT_SYMBOL(ppp_register_channel);
3295 EXPORT_SYMBOL(ppp_unregister_channel);
3296 EXPORT_SYMBOL(ppp_channel_index);
3297 EXPORT_SYMBOL(ppp_unit_number);
3298 EXPORT_SYMBOL(ppp_dev_name);
3299 EXPORT_SYMBOL(ppp_input);
3300 EXPORT_SYMBOL(ppp_input_error);
3301 EXPORT_SYMBOL(ppp_output_wakeup);
3302 EXPORT_SYMBOL(ppp_register_compressor);
3303 EXPORT_SYMBOL(ppp_unregister_compressor);
3304 MODULE_LICENSE("GPL");
3305 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3306 MODULE_ALIAS_RTNL_LINK("ppp");
3307 MODULE_ALIAS("devname:ppp");