drivers/net/ppp/ppp_generic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic PPP layer for Linux.
   4  *
   5  * Copyright 1999-2002 Paul Mackerras.
   6  *
   7  * The generic PPP layer handles the PPP network interfaces, the
   8  * /dev/ppp device, packet and VJ compression, and multilink.
   9  * It talks to PPP `channels' via the interface defined in
  10  * include/linux/ppp_channel.h.  Channels provide the basic means for
  11  * sending and receiving PPP frames on some kind of communications
  12  * channel.
  13  *
  14  * Part of the code in this driver was inspired by the old async-only
  15  * PPP driver, written by Michael Callahan and Al Longyear, and
  16  * subsequently hacked by Paul Mackerras.
  17  *
  18  * ==FILEVERSION 20041108==
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched/signal.h>
  24 #include <linux/kmod.h>
  25 #include <linux/init.h>
  26 #include <linux/list.h>
  27 #include <linux/idr.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/poll.h>
  30 #include <linux/ppp_defs.h>
  31 #include <linux/filter.h>
  32 #include <linux/ppp-ioctl.h>
  33 #include <linux/ppp_channel.h>
  34 #include <linux/ppp-comp.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/rtnetlink.h>
  37 #include <linux/if_arp.h>
  38 #include <linux/ip.h>
  39 #include <linux/tcp.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/rwsem.h>
  42 #include <linux/stddef.h>
  43 #include <linux/device.h>
  44 #include <linux/mutex.h>
  45 #include <linux/slab.h>
  46 #include <linux/file.h>
  47 #include <linux/unaligned.h>
  48 #include <net/slhc_vj.h>
  49 #include <linux/atomic.h>
  50 #include <linux/refcount.h>
  51
  52 #include <linux/nsproxy.h>
  53 #include <net/net_namespace.h>
  54 #include <net/netns/generic.h>
  55
  56 #define PPP_VERSION     "2.4.2"
  57
  58 /*
  59  * Network protocols we support.
  60  */
  61 #define NP_IP   0               /* Internet Protocol V4 */
  62 #define NP_IPV6 1               /* Internet Protocol V6 */
  63 #define NP_IPX  2               /* IPX protocol */
  64 #define NP_AT   3               /* Appletalk protocol */
  65 #define NP_MPLS_UC 4            /* MPLS unicast */
  66 #define NP_MPLS_MC 5            /* MPLS multicast */
  67 #define NUM_NP  6               /* Number of NPs. */
  68
  69 #define MPHDRLEN        6       /* multilink protocol header length */
  70 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  71
  72 #define PPP_PROTO_LEN   2
  73 #define PPP_LCP_HDRLEN  4
  74
  75 /*
  76  * An instance of /dev/ppp can be associated with either a ppp
  77  * interface unit or a ppp channel.  In both cases, file->private_data
  78  * points to one of these.
  79  */
  80 struct ppp_file {
  81         enum {
  82                 INTERFACE=1, CHANNEL
  83         }               kind;
  84         struct sk_buff_head xq;         /* pppd transmit queue */
  85         struct sk_buff_head rq;         /* receive queue for pppd */
  86         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  87         refcount_t      refcnt;         /* # refs (incl /dev/ppp attached) */
  88         int             hdrlen;         /* space to leave for headers */
  89         int             index;          /* interface unit / channel number */
  90         int             dead;           /* unit/channel has been shut down */
  91 };
  92
  93 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  94
  95 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  96 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  97
  98 /*
  99  * Data structure to hold primary network stats for which
 100  * we want to use 64 bit storage.  Other network stats
 101  * are stored in dev->stats of the ppp strucute.
 102  */
 103 struct ppp_link_stats {
 104         u64 rx_packets;
 105         u64 tx_packets;
 106         u64 rx_bytes;
 107         u64 tx_bytes;
 108 };
 109
 110 /*
 111  * Data structure describing one ppp unit.
 112  * A ppp unit corresponds to a ppp network interface device
 113  * and represents a multilink bundle.
 114  * It can have 0 or more ppp channels connected to it.
 115  */
 116 struct ppp {
 117         struct ppp_file file;           /* stuff for read/write/poll 0 */
 118         struct file     *owner;         /* file that owns this unit 48 */
 119         struct list_head channels;      /* list of attached channels 4c */
 120         int             n_channels;     /* how many channels are attached 54 */
 121         spinlock_t      rlock;          /* lock for receive side 58 */
 122         spinlock_t      wlock;          /* lock for transmit side 5c */
 123         int __percpu    *xmit_recursion; /* xmit recursion detect */
 124         int             mru;            /* max receive unit 60 */
 125         unsigned int    flags;          /* control bits 64 */
 126         unsigned int    xstate;         /* transmit state bits 68 */
 127         unsigned int    rstate;         /* receive state bits 6c */
 128         int             debug;          /* debug flags 70 */
 129         struct slcompress *vj;          /* state for VJ header compression */
 130         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 131         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 132         struct compressor *xcomp;       /* transmit packet compressor 8c */
 133         void            *xc_state;      /* its internal state 90 */
 134         struct compressor *rcomp;       /* receive decompressor 94 */
 135         void            *rc_state;      /* its internal state 98 */
 136         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 137         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 138         struct net_device *dev;         /* network interface device a4 */
 139         int             closing;        /* is device closing down? a8 */
 140 #ifdef CONFIG_PPP_MULTILINK
 141         int             nxchan;         /* next channel to send something on */
 142         u32             nxseq;          /* next sequence number to send */
 143         int             mrru;           /* MP: max reconst. receive unit */
 144         u32             nextseq;        /* MP: seq no of next packet */
 145         u32             minseq;         /* MP: min of most recent seqnos */
 146         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 147 #endif /* CONFIG_PPP_MULTILINK */
 148 #ifdef CONFIG_PPP_FILTER
 149         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 150         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 151 #endif /* CONFIG_PPP_FILTER */
 152         struct net      *ppp_net;       /* the net we belong to */
 153         struct ppp_link_stats stats64;  /* 64 bit network stats */
 154 };
 155
 156 /*
 157  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 158  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 159  * SC_MUST_COMP
 160  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 161  * Bits in xstate: SC_COMP_RUN
 162  */
 163 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 164                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 165                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 166
 167 /*
 168  * Private data structure for each channel.
 169  * This includes the data structure used for multilink.
 170  */
 171 struct channel {
 172         struct ppp_file file;           /* stuff for read/write/poll */
 173         struct list_head list;          /* link in all/new_channels list */
 174         struct ppp_channel *chan;       /* public channel data structure */
 175         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 176         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 177         struct ppp      *ppp;           /* ppp unit we're connected to */
 178         struct net      *chan_net;      /* the net channel belongs to */
 179         netns_tracker   ns_tracker;
 180         struct list_head clist;         /* link in list of channels per unit */
 181         rwlock_t        upl;            /* protects `ppp' and 'bridge' */
 182         struct channel __rcu *bridge;   /* "bridged" ppp channel */
 183 #ifdef CONFIG_PPP_MULTILINK
 184         u8              avail;          /* flag used in multilink stuff */
 185         u8              had_frag;       /* >= 1 fragments have been sent */
 186         u32             lastseq;        /* MP: last sequence # received */
 187         int             speed;          /* speed of the corresponding ppp channel*/
 188 #endif /* CONFIG_PPP_MULTILINK */
 189 };
 190
 191 struct ppp_config {
 192         struct file *file;
 193         s32 unit;
 194         bool ifname_is_set;
 195 };
 196
 197 /*
 198  * SMP locking issues:
 199  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 200  * list and the ppp.n_channels field, you need to take both locks
 201  * before you modify them.
 202  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 203  * channel.downl.
 204  */
 205
 206 static DEFINE_MUTEX(ppp_mutex);
 207 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 208 static atomic_t channel_count = ATOMIC_INIT(0);
 209
 210 /* per-net private data for this module */
 211 static unsigned int ppp_net_id __read_mostly;
 212 struct ppp_net {
 213         /* units to ppp mapping */
 214         struct idr units_idr;
 215
 216         /*
 217          * all_ppp_mutex protects the units_idr mapping.
 218          * It also ensures that finding a ppp unit in the units_idr
 219          * map and updating its file.refcnt field is atomic.
 220          */
 221         struct mutex all_ppp_mutex;
 222
 223         /* channels */
 224         struct list_head all_channels;
 225         struct list_head new_channels;
 226         int last_channel_index;
 227
 228         /*
 229          * all_channels_lock protects all_channels and
 230          * last_channel_index, and the atomicity of find
 231          * a channel and updating its file.refcnt field.
 232          */
 233         spinlock_t all_channels_lock;
 234 };
 235
 236 /* Get the PPP protocol number from a skb */
 237 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 238
 239 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 240 #define PPP_MAX_RQLEN   32
 241
 242 /*
 243  * Maximum number of multilink fragments queued up.
 244  * This has to be large enough to cope with the maximum latency of
 245  * the slowest channel relative to the others.  Strictly it should
 246  * depend on the number of channels and their characteristics.
 247  */
 248 #define PPP_MP_MAX_QLEN 128
 249
 250 /* Multilink header bits. */
 251 #define B       0x80            /* this fragment begins a packet */
 252 #define E       0x40            /* this fragment ends a packet */
 253
 254 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 255 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 256 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 257
 258 /* Prototypes. */
 259 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 260                         struct file *file, unsigned int cmd, unsigned long arg);
 261 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 262 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 263 static void ppp_push(struct ppp *ppp);
 264 static void ppp_channel_push(struct channel *pch);
 265 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 266                               struct channel *pch);
 267 static void ppp_receive_error(struct ppp *ppp);
 268 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 269 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 270                                             struct sk_buff *skb);
 271 #ifdef CONFIG_PPP_MULTILINK
 272 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 273                                 struct channel *pch);
 274 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 275 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 276 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 277 #endif /* CONFIG_PPP_MULTILINK */
 278 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
 279 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 280 static void ppp_ccp_closed(struct ppp *ppp);
 281 static struct compressor *find_compressor(int type);
 282 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 283 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 284 static void init_ppp_file(struct ppp_file *pf, int kind);
 285 static void ppp_destroy_interface(struct ppp *ppp);
 286 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 287 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 288 static int ppp_connect_channel(struct channel *pch, int unit);
 289 static int ppp_disconnect_channel(struct channel *pch);
 290 static void ppp_destroy_channel(struct channel *pch);
 291 static int unit_get(struct idr *p, void *ptr, int min);
 292 static int unit_set(struct idr *p, void *ptr, int n);
 293 static void unit_put(struct idr *p, int n);
 294 static void *unit_find(struct idr *p, int n);
 295 static void ppp_setup(struct net_device *dev);
 296
 297 static const struct net_device_ops ppp_netdev_ops;
 298
 299 static const struct class ppp_class = {
 300         .name = "ppp",
 301 };
 302
 303 /* per net-namespace data */
 304 static inline struct ppp_net *ppp_pernet(struct net *net)
 305 {
 306         return net_generic(net, ppp_net_id);
 307 }
 308
 309 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 310 static inline int proto_to_npindex(int proto)
 311 {
 312         switch (proto) {
 313         case PPP_IP:
 314                 return NP_IP;
 315         case PPP_IPV6:
 316                 return NP_IPV6;
 317         case PPP_IPX:
 318                 return NP_IPX;
 319         case PPP_AT:
 320                 return NP_AT;
 321         case PPP_MPLS_UC:
 322                 return NP_MPLS_UC;
 323         case PPP_MPLS_MC:
 324                 return NP_MPLS_MC;
 325         }
 326         return -EINVAL;
 327 }
 328
 329 /* Translates an NP index into a PPP protocol number */
 330 static const int npindex_to_proto[NUM_NP] = {
 331         PPP_IP,
 332         PPP_IPV6,
 333         PPP_IPX,
 334         PPP_AT,
 335         PPP_MPLS_UC,
 336         PPP_MPLS_MC,
 337 };
 338
 339 /* Translates an ethertype into an NP index */
 340 static inline int ethertype_to_npindex(int ethertype)
 341 {
 342         switch (ethertype) {
 343         case ETH_P_IP:
 344                 return NP_IP;
 345         case ETH_P_IPV6:
 346                 return NP_IPV6;
 347         case ETH_P_IPX:
 348                 return NP_IPX;
 349         case ETH_P_PPPTALK:
 350         case ETH_P_ATALK:
 351                 return NP_AT;
 352         case ETH_P_MPLS_UC:
 353                 return NP_MPLS_UC;
 354         case ETH_P_MPLS_MC:
 355                 return NP_MPLS_MC;
 356         }
 357         return -1;
 358 }
 359
 360 /* Translates an NP index into an ethertype */
 361 static const int npindex_to_ethertype[NUM_NP] = {
 362         ETH_P_IP,
 363         ETH_P_IPV6,
 364         ETH_P_IPX,
 365         ETH_P_PPPTALK,
 366         ETH_P_MPLS_UC,
 367         ETH_P_MPLS_MC,
 368 };
 369
 370 /*
 371  * Locking shorthand.
 372  */
 373 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 374 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 375 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 376 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 377 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 378                                      ppp_recv_lock(ppp); } while (0)
 379 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 380                                      ppp_xmit_unlock(ppp); } while (0)
 381
 382 /*
 383  * /dev/ppp device routines.
 384  * The /dev/ppp device is used by pppd to control the ppp unit.
 385  * It supports the read, write, ioctl and poll functions.
 386  * Open instances of /dev/ppp can be in one of three states:
 387  * unattached, attached to a ppp unit, or attached to a ppp channel.
 388  */
 389 static int ppp_open(struct inode *inode, struct file *file)
 390 {
 391         /*
 392          * This could (should?) be enforced by the permissions on /dev/ppp.
 393          */
 394         if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
 395                 return -EPERM;
 396         return 0;
 397 }
 398
 399 static int ppp_release(struct inode *unused, struct file *file)
 400 {
 401         struct ppp_file *pf = file->private_data;
 402         struct ppp *ppp;
 403
 404         if (pf) {
 405                 file->private_data = NULL;
 406                 if (pf->kind == INTERFACE) {
 407                         ppp = PF_TO_PPP(pf);
 408                         rtnl_lock();
 409                         if (file == ppp->owner)
 410                                 unregister_netdevice(ppp->dev);
 411                         rtnl_unlock();
 412                 }
 413                 if (refcount_dec_and_test(&pf->refcnt)) {
 414                         switch (pf->kind) {
 415                         case INTERFACE:
 416                                 ppp_destroy_interface(PF_TO_PPP(pf));
 417                                 break;
 418                         case CHANNEL:
 419                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 420                                 break;
 421                         }
 422                 }
 423         }
 424         return 0;
 425 }
 426
 427 static ssize_t ppp_read(struct file *file, char __user *buf,
 428                         size_t count, loff_t *ppos)
 429 {
 430         struct ppp_file *pf = file->private_data;
 431         DECLARE_WAITQUEUE(wait, current);
 432         ssize_t ret;
 433         struct sk_buff *skb = NULL;
 434         struct iovec iov;
 435         struct iov_iter to;
 436
 437         ret = count;
 438
 439         if (!pf)
 440                 return -ENXIO;
 441         add_wait_queue(&pf->rwait, &wait);
 442         for (;;) {
 443                 set_current_state(TASK_INTERRUPTIBLE);
 444                 skb = skb_dequeue(&pf->rq);
 445                 if (skb)
 446                         break;
 447                 ret = 0;
 448                 if (pf->dead)
 449                         break;
 450                 if (pf->kind == INTERFACE) {
 451                         /*
 452                          * Return 0 (EOF) on an interface that has no
 453                          * channels connected, unless it is looping
 454                          * network traffic (demand mode).
 455                          */
 456                         struct ppp *ppp = PF_TO_PPP(pf);
 457
 458                         ppp_recv_lock(ppp);
 459                         if (ppp->n_channels == 0 &&
 460                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 461                                 ppp_recv_unlock(ppp);
 462                                 break;
 463                         }
 464                         ppp_recv_unlock(ppp);
 465                 }
 466                 ret = -EAGAIN;
 467                 if (file->f_flags & O_NONBLOCK)
 468                         break;
 469                 ret = -ERESTARTSYS;
 470                 if (signal_pending(current))
 471                         break;
 472                 schedule();
 473         }
 474         set_current_state(TASK_RUNNING);
 475         remove_wait_queue(&pf->rwait, &wait);
 476
 477         if (!skb)
 478                 goto out;
 479
 480         ret = -EOVERFLOW;
 481         if (skb->len > count)
 482                 goto outf;
 483         ret = -EFAULT;
 484         iov.iov_base = buf;
 485         iov.iov_len = count;
 486         iov_iter_init(&to, ITER_DEST, &iov, 1, count);
 487         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 488                 goto outf;
 489         ret = skb->len;
 490
 491  outf:
 492         kfree_skb(skb);
 493  out:
 494         return ret;
 495 }
 496
 497 static bool ppp_check_packet(struct sk_buff *skb, size_t count)
 498 {
 499         /* LCP packets must include LCP header which 4 bytes long:
 500          * 1-byte code, 1-byte identifier, and 2-byte length.
 501          */
 502         return get_unaligned_be16(skb->data) != PPP_LCP ||
 503                 count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
 504 }
 505
 506 static ssize_t ppp_write(struct file *file, const char __user *buf,
 507                          size_t count, loff_t *ppos)
 508 {
 509         struct ppp_file *pf = file->private_data;
 510         struct sk_buff *skb;
 511         ssize_t ret;
 512
 513         if (!pf)
 514                 return -ENXIO;
 515         /* All PPP packets should start with the 2-byte protocol */
 516         if (count < PPP_PROTO_LEN)
 517                 return -EINVAL;
 518         ret = -ENOMEM;
 519         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 520         if (!skb)
 521                 goto out;
 522         skb_reserve(skb, pf->hdrlen);
 523         ret = -EFAULT;
 524         if (copy_from_user(skb_put(skb, count), buf, count)) {
 525                 kfree_skb(skb);
 526                 goto out;
 527         }
 528         ret = -EINVAL;
 529         if (unlikely(!ppp_check_packet(skb, count))) {
 530                 kfree_skb(skb);
 531                 goto out;
 532         }
 533
 534         switch (pf->kind) {
 535         case INTERFACE:
 536                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 537                 break;
 538         case CHANNEL:
 539                 skb_queue_tail(&pf->xq, skb);
 540                 ppp_channel_push(PF_TO_CHANNEL(pf));
 541                 break;
 542         }
 543
 544         ret = count;
 545
 546  out:
 547         return ret;
 548 }
 549
 550 /* No kernel lock - fine */
 551 static __poll_t ppp_poll(struct file *file, poll_table *wait)
 552 {
 553         struct ppp_file *pf = file->private_data;
 554         __poll_t mask;
 555
 556         if (!pf)
 557                 return 0;
 558         poll_wait(file, &pf->rwait, wait);
 559         mask = EPOLLOUT | EPOLLWRNORM;
 560         if (skb_peek(&pf->rq))
 561                 mask |= EPOLLIN | EPOLLRDNORM;
 562         if (pf->dead)
 563                 mask |= EPOLLHUP;
 564         else if (pf->kind == INTERFACE) {
 565                 /* see comment in ppp_read */
 566                 struct ppp *ppp = PF_TO_PPP(pf);
 567
 568                 ppp_recv_lock(ppp);
 569                 if (ppp->n_channels == 0 &&
 570                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 571                         mask |= EPOLLIN | EPOLLRDNORM;
 572                 ppp_recv_unlock(ppp);
 573         }
 574
 575         return mask;
 576 }
 577
 578 #ifdef CONFIG_PPP_FILTER
 579 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
 580 {
 581         struct sock_fprog_kern fprog;
 582         struct bpf_prog *res = NULL;
 583         int err;
 584
 585         if (!uprog->len)
 586                 return NULL;
 587
 588         /* uprog->len is unsigned short, so no overflow here */
 589         fprog.len = uprog->len;
 590         fprog.filter = memdup_array_user(uprog->filter,
 591                                          uprog->len, sizeof(struct sock_filter));
 592         if (IS_ERR(fprog.filter))
 593                 return ERR_CAST(fprog.filter);
 594
 595         err = bpf_prog_create(&res, &fprog);
 596         kfree(fprog.filter);
 597
 598         return err ? ERR_PTR(err) : res;
 599 }
 600
 601 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
 602 {
 603         struct sock_fprog uprog;
 604
 605         if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
 606                 return ERR_PTR(-EFAULT);
 607         return get_filter(&uprog);
 608 }
 609
 610 #ifdef CONFIG_COMPAT
 611 struct sock_fprog32 {
 612         unsigned short len;
 613         compat_caddr_t filter;
 614 };
 615
 616 #define PPPIOCSPASS32           _IOW('t', 71, struct sock_fprog32)
 617 #define PPPIOCSACTIVE32         _IOW('t', 70, struct sock_fprog32)
 618
 619 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
 620 {
 621         struct sock_fprog32 uprog32;
 622         struct sock_fprog uprog;
 623
 624         if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
 625                 return ERR_PTR(-EFAULT);
 626         uprog.len = uprog32.len;
 627         uprog.filter = compat_ptr(uprog32.filter);
 628         return get_filter(&uprog);
 629 }
 630 #endif
 631 #endif
 632
 633 /* Bridge one PPP channel to another.
 634  * When two channels are bridged, ppp_input on one channel is redirected to
 635  * the other's ops->start_xmit handler.
 636  * In order to safely bridge channels we must reject channels which are already
 637  * part of a bridge instance, or which form part of an existing unit.
 638  * Once successfully bridged, each channel holds a reference on the other
 639  * to prevent it being freed while the bridge is extant.
 640  */
 641 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
 642 {
 643         write_lock_bh(&pch->upl);
 644         if (pch->ppp ||
 645             rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
 646                 write_unlock_bh(&pch->upl);
 647                 return -EALREADY;
 648         }
 649         refcount_inc(&pchb->file.refcnt);
 650         rcu_assign_pointer(pch->bridge, pchb);
 651         write_unlock_bh(&pch->upl);
 652
 653         write_lock_bh(&pchb->upl);
 654         if (pchb->ppp ||
 655             rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
 656                 write_unlock_bh(&pchb->upl);
 657                 goto err_unset;
 658         }
 659         refcount_inc(&pch->file.refcnt);
 660         rcu_assign_pointer(pchb->bridge, pch);
 661         write_unlock_bh(&pchb->upl);
 662
 663         return 0;
 664
 665 err_unset:
 666         write_lock_bh(&pch->upl);
 667         /* Re-read pch->bridge with upl held in case it was modified concurrently */
 668         pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
 669         RCU_INIT_POINTER(pch->bridge, NULL);
 670         write_unlock_bh(&pch->upl);
 671         synchronize_rcu();
 672
 673         if (pchb)
 674                 if (refcount_dec_and_test(&pchb->file.refcnt))
 675                         ppp_destroy_channel(pchb);
 676
 677         return -EALREADY;
 678 }
 679
 680 static int ppp_unbridge_channels(struct channel *pch)
 681 {
 682         struct channel *pchb, *pchbb;
 683
 684         write_lock_bh(&pch->upl);
 685         pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
 686         if (!pchb) {
 687                 write_unlock_bh(&pch->upl);
 688                 return -EINVAL;
 689         }
 690         RCU_INIT_POINTER(pch->bridge, NULL);
 691         write_unlock_bh(&pch->upl);
 692
 693         /* Only modify pchb if phcb->bridge points back to pch.
 694          * If not, it implies that there has been a race unbridging (and possibly
 695          * even rebridging) pchb.  We should leave pchb alone to avoid either a
 696          * refcount underflow, or breaking another established bridge instance.
 697          */
 698         write_lock_bh(&pchb->upl);
 699         pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
 700         if (pchbb == pch)
 701                 RCU_INIT_POINTER(pchb->bridge, NULL);
 702         write_unlock_bh(&pchb->upl);
 703
 704         synchronize_rcu();
 705
 706         if (pchbb == pch)
 707                 if (refcount_dec_and_test(&pch->file.refcnt))
 708                         ppp_destroy_channel(pch);
 709
 710         if (refcount_dec_and_test(&pchb->file.refcnt))
 711                 ppp_destroy_channel(pchb);
 712
 713         return 0;
 714 }
 715
 716 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 717 {
 718         struct ppp_file *pf;
 719         struct ppp *ppp;
 720         int err = -EFAULT, val, val2, i;
 721         struct ppp_idle32 idle32;
 722         struct ppp_idle64 idle64;
 723         struct npioctl npi;
 724         int unit, cflags;
 725         struct slcompress *vj;
 726         void __user *argp = (void __user *)arg;
 727         int __user *p = argp;
 728
 729         mutex_lock(&ppp_mutex);
 730
 731         pf = file->private_data;
 732         if (!pf) {
 733                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 734                                            pf, file, cmd, arg);
 735                 goto out;
 736         }
 737
 738         if (cmd == PPPIOCDETACH) {
 739                 /*
 740                  * PPPIOCDETACH is no longer supported as it was heavily broken,
 741                  * and is only known to have been used by pppd older than
 742                  * ppp-2.4.2 (released November 2003).
 743                  */
 744                 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
 745                              current->comm, current->pid);
 746                 err = -EINVAL;
 747                 goto out;
 748         }
 749
 750         if (pf->kind == CHANNEL) {
 751                 struct channel *pch, *pchb;
 752                 struct ppp_channel *chan;
 753                 struct ppp_net *pn;
 754
 755                 pch = PF_TO_CHANNEL(pf);
 756
 757                 switch (cmd) {
 758                 case PPPIOCCONNECT:
 759                         if (get_user(unit, p))
 760                                 break;
 761                         err = ppp_connect_channel(pch, unit);
 762                         break;
 763
 764                 case PPPIOCDISCONN:
 765                         err = ppp_disconnect_channel(pch);
 766                         break;
 767
 768                 case PPPIOCBRIDGECHAN:
 769                         if (get_user(unit, p))
 770                                 break;
 771                         err = -ENXIO;
 772                         pn = ppp_pernet(current->nsproxy->net_ns);
 773                         spin_lock_bh(&pn->all_channels_lock);
 774                         pchb = ppp_find_channel(pn, unit);
 775                         /* Hold a reference to prevent pchb being freed while
 776                          * we establish the bridge.
 777                          */
 778                         if (pchb)
 779                                 refcount_inc(&pchb->file.refcnt);
 780                         spin_unlock_bh(&pn->all_channels_lock);
 781                         if (!pchb)
 782                                 break;
 783                         err = ppp_bridge_channels(pch, pchb);
 784                         /* Drop earlier refcount now bridge establishment is complete */
 785                         if (refcount_dec_and_test(&pchb->file.refcnt))
 786                                 ppp_destroy_channel(pchb);
 787                         break;
 788
 789                 case PPPIOCUNBRIDGECHAN:
 790                         err = ppp_unbridge_channels(pch);
 791                         break;
 792
 793                 default:
 794                         down_read(&pch->chan_sem);
 795                         chan = pch->chan;
 796                         err = -ENOTTY;
 797                         if (chan && chan->ops->ioctl)
 798                                 err = chan->ops->ioctl(chan, cmd, arg);
 799                         up_read(&pch->chan_sem);
 800                 }
 801                 goto out;
 802         }
 803
 804         if (pf->kind != INTERFACE) {
 805                 /* can't happen */
 806                 pr_err("PPP: not interface or channel??\n");
 807                 err = -EINVAL;
 808                 goto out;
 809         }
 810
 811         ppp = PF_TO_PPP(pf);
 812         switch (cmd) {
 813         case PPPIOCSMRU:
 814                 if (get_user(val, p))
 815                         break;
 816                 ppp->mru = val;
 817                 err = 0;
 818                 break;
 819
 820         case PPPIOCSFLAGS:
 821                 if (get_user(val, p))
 822                         break;
 823                 ppp_lock(ppp);
 824                 cflags = ppp->flags & ~val;
 825 #ifdef CONFIG_PPP_MULTILINK
 826                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 827                         ppp->nextseq = 0;
 828 #endif
 829                 ppp->flags = val & SC_FLAG_BITS;
 830                 ppp_unlock(ppp);
 831                 if (cflags & SC_CCP_OPEN)
 832                         ppp_ccp_closed(ppp);
 833                 err = 0;
 834                 break;
 835
 836         case PPPIOCGFLAGS:
 837                 val = ppp->flags | ppp->xstate | ppp->rstate;
 838                 if (put_user(val, p))
 839                         break;
 840                 err = 0;
 841                 break;
 842
 843         case PPPIOCSCOMPRESS:
 844         {
 845                 struct ppp_option_data data;
 846                 if (copy_from_user(&data, argp, sizeof(data)))
 847                         err = -EFAULT;
 848                 else
 849                         err = ppp_set_compress(ppp, &data);
 850                 break;
 851         }
 852         case PPPIOCGUNIT:
 853                 if (put_user(ppp->file.index, p))
 854                         break;
 855                 err = 0;
 856                 break;
 857
 858         case PPPIOCSDEBUG:
 859                 if (get_user(val, p))
 860                         break;
 861                 ppp->debug = val;
 862                 err = 0;
 863                 break;
 864
 865         case PPPIOCGDEBUG:
 866                 if (put_user(ppp->debug, p))
 867                         break;
 868                 err = 0;
 869                 break;
 870
 871         case PPPIOCGIDLE32:
 872                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 873                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
 874                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
 875                         break;
 876                 err = 0;
 877                 break;
 878
 879         case PPPIOCGIDLE64:
 880                 idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 881                 idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
 882                 if (copy_to_user(argp, &idle64, sizeof(idle64)))
 883                         break;
 884                 err = 0;
 885                 break;
 886
 887         case PPPIOCSMAXCID:
 888                 if (get_user(val, p))
 889                         break;
 890                 val2 = 15;
 891                 if ((val >> 16) != 0) {
 892                         val2 = val >> 16;
 893                         val &= 0xffff;
 894                 }
 895                 vj = slhc_init(val2+1, val+1);
 896                 if (IS_ERR(vj)) {
 897                         err = PTR_ERR(vj);
 898                         break;
 899                 }
 900                 ppp_lock(ppp);
 901                 if (ppp->vj)
 902                         slhc_free(ppp->vj);
 903                 ppp->vj = vj;
 904                 ppp_unlock(ppp);
 905                 err = 0;
 906                 break;
 907
 908         case PPPIOCGNPMODE:
 909         case PPPIOCSNPMODE:
 910                 if (copy_from_user(&npi, argp, sizeof(npi)))
 911                         break;
 912                 err = proto_to_npindex(npi.protocol);
 913                 if (err < 0)
 914                         break;
 915                 i = err;
 916                 if (cmd == PPPIOCGNPMODE) {
 917                         err = -EFAULT;
 918                         npi.mode = ppp->npmode[i];
 919                         if (copy_to_user(argp, &npi, sizeof(npi)))
 920                                 break;
 921                 } else {
 922                         ppp->npmode[i] = npi.mode;
 923                         /* we may be able to transmit more packets now (??) */
 924                         netif_wake_queue(ppp->dev);
 925                 }
 926                 err = 0;
 927                 break;
 928
 929 #ifdef CONFIG_PPP_FILTER
 930         case PPPIOCSPASS:
 931         case PPPIOCSACTIVE:
 932         {
 933                 struct bpf_prog *filter = ppp_get_filter(argp);
 934                 struct bpf_prog **which;
 935
 936                 if (IS_ERR(filter)) {
 937                         err = PTR_ERR(filter);
 938                         break;
 939                 }
 940                 if (cmd == PPPIOCSPASS)
 941                         which = &ppp->pass_filter;
 942                 else
 943                         which = &ppp->active_filter;
 944                 ppp_lock(ppp);
 945                 if (*which)
 946                         bpf_prog_destroy(*which);
 947                 *which = filter;
 948                 ppp_unlock(ppp);
 949                 err = 0;
 950                 break;
 951         }
 952 #endif /* CONFIG_PPP_FILTER */
 953
 954 #ifdef CONFIG_PPP_MULTILINK
 955         case PPPIOCSMRRU:
 956                 if (get_user(val, p))
 957                         break;
 958                 ppp_recv_lock(ppp);
 959                 ppp->mrru = val;
 960                 ppp_recv_unlock(ppp);
 961                 err = 0;
 962                 break;
 963 #endif /* CONFIG_PPP_MULTILINK */
 964
 965         default:
 966                 err = -ENOTTY;
 967         }
 968
 969 out:
 970         mutex_unlock(&ppp_mutex);
 971
 972         return err;
 973 }
 974
 975 #ifdef CONFIG_COMPAT
 976 struct ppp_option_data32 {
 977         compat_uptr_t           ptr;
 978         u32                     length;
 979         compat_int_t            transmit;
 980 };
 981 #define PPPIOCSCOMPRESS32       _IOW('t', 77, struct ppp_option_data32)
 982
 983 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 984 {
 985         struct ppp_file *pf;
 986         int err = -ENOIOCTLCMD;
 987         void __user *argp = (void __user *)arg;
 988
 989         mutex_lock(&ppp_mutex);
 990
 991         pf = file->private_data;
 992         if (pf && pf->kind == INTERFACE) {
 993                 struct ppp *ppp = PF_TO_PPP(pf);
 994                 switch (cmd) {
 995 #ifdef CONFIG_PPP_FILTER
 996                 case PPPIOCSPASS32:
 997                 case PPPIOCSACTIVE32:
 998                 {
 999                         struct bpf_prog *filter = compat_ppp_get_filter(argp);
1000                         struct bpf_prog **which;
1001
1002                         if (IS_ERR(filter)) {
1003                                 err = PTR_ERR(filter);
1004                                 break;
1005                         }
1006                         if (cmd == PPPIOCSPASS32)
1007                                 which = &ppp->pass_filter;
1008                         else
1009                                 which = &ppp->active_filter;
1010                         ppp_lock(ppp);
1011                         if (*which)
1012                                 bpf_prog_destroy(*which);
1013                         *which = filter;
1014                         ppp_unlock(ppp);
1015                         err = 0;
1016                         break;
1017                 }
1018 #endif /* CONFIG_PPP_FILTER */
1019                 case PPPIOCSCOMPRESS32:
1020                 {
1021                         struct ppp_option_data32 data32;
1022                         if (copy_from_user(&data32, argp, sizeof(data32))) {
1023                                 err = -EFAULT;
1024                         } else {
1025                                 struct ppp_option_data data = {
1026                                         .ptr = compat_ptr(data32.ptr),
1027                                         .length = data32.length,
1028                                         .transmit = data32.transmit
1029                                 };
1030                                 err = ppp_set_compress(ppp, &data);
1031                         }
1032                         break;
1033                 }
1034                 }
1035         }
1036         mutex_unlock(&ppp_mutex);
1037
1038         /* all other commands have compatible arguments */
1039         if (err == -ENOIOCTLCMD)
1040                 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1041
1042         return err;
1043 }
1044 #endif
1045
1046 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1047                         struct file *file, unsigned int cmd, unsigned long arg)
1048 {
1049         int unit, err = -EFAULT;
1050         struct ppp *ppp;
1051         struct channel *chan;
1052         struct ppp_net *pn;
1053         int __user *p = (int __user *)arg;
1054
1055         switch (cmd) {
1056         case PPPIOCNEWUNIT:
1057                 /* Create a new ppp unit */
1058                 if (get_user(unit, p))
1059                         break;
1060                 err = ppp_create_interface(net, file, &unit);
1061                 if (err < 0)
1062                         break;
1063
1064                 err = -EFAULT;
1065                 if (put_user(unit, p))
1066                         break;
1067                 err = 0;
1068                 break;
1069
1070         case PPPIOCATTACH:
1071                 /* Attach to an existing ppp unit */
1072                 if (get_user(unit, p))
1073                         break;
1074                 err = -ENXIO;
1075                 pn = ppp_pernet(net);
1076                 mutex_lock(&pn->all_ppp_mutex);
1077                 ppp = ppp_find_unit(pn, unit);
1078                 if (ppp) {
1079                         refcount_inc(&ppp->file.refcnt);
1080                         file->private_data = &ppp->file;
1081                         err = 0;
1082                 }
1083                 mutex_unlock(&pn->all_ppp_mutex);
1084                 break;
1085
1086         case PPPIOCATTCHAN:
1087                 if (get_user(unit, p))
1088                         break;
1089                 err = -ENXIO;
1090                 pn = ppp_pernet(net);
1091                 spin_lock_bh(&pn->all_channels_lock);
1092                 chan = ppp_find_channel(pn, unit);
1093                 if (chan) {
1094                         refcount_inc(&chan->file.refcnt);
1095                         file->private_data = &chan->file;
1096                         err = 0;
1097                 }
1098                 spin_unlock_bh(&pn->all_channels_lock);
1099                 break;
1100
1101         default:
1102                 err = -ENOTTY;
1103         }
1104
1105         return err;
1106 }
1107
1108 static const struct file_operations ppp_device_fops = {
1109         .owner          = THIS_MODULE,
1110         .read           = ppp_read,
1111         .write          = ppp_write,
1112         .poll           = ppp_poll,
1113         .unlocked_ioctl = ppp_ioctl,
1114 #ifdef CONFIG_COMPAT
1115         .compat_ioctl   = ppp_compat_ioctl,
1116 #endif
1117         .open           = ppp_open,
1118         .release        = ppp_release,
1119         .llseek         = noop_llseek,
1120 };
1121
1122 static __net_init int ppp_init_net(struct net *net)
1123 {
1124         struct ppp_net *pn = net_generic(net, ppp_net_id);
1125
1126         idr_init(&pn->units_idr);
1127         mutex_init(&pn->all_ppp_mutex);
1128
1129         INIT_LIST_HEAD(&pn->all_channels);
1130         INIT_LIST_HEAD(&pn->new_channels);
1131
1132         spin_lock_init(&pn->all_channels_lock);
1133
1134         return 0;
1135 }
1136
1137 static __net_exit void ppp_exit_net(struct net *net)
1138 {
1139         struct ppp_net *pn = net_generic(net, ppp_net_id);
1140         struct net_device *dev;
1141         struct net_device *aux;
1142         struct ppp *ppp;
1143         LIST_HEAD(list);
1144         int id;
1145
1146         rtnl_lock();
1147         for_each_netdev_safe(net, dev, aux) {
1148                 if (dev->netdev_ops == &ppp_netdev_ops)
1149                         unregister_netdevice_queue(dev, &list);
1150         }
1151
1152         idr_for_each_entry(&pn->units_idr, ppp, id)
1153                 /* Skip devices already unregistered by previous loop */
1154                 if (!net_eq(dev_net(ppp->dev), net))
1155                         unregister_netdevice_queue(ppp->dev, &list);
1156
1157         unregister_netdevice_many(&list);
1158         rtnl_unlock();
1159
1160         mutex_destroy(&pn->all_ppp_mutex);
1161         idr_destroy(&pn->units_idr);
1162         WARN_ON_ONCE(!list_empty(&pn->all_channels));
1163         WARN_ON_ONCE(!list_empty(&pn->new_channels));
1164 }
1165
1166 static struct pernet_operations ppp_net_ops = {
1167         .init = ppp_init_net,
1168         .exit = ppp_exit_net,
1169         .id   = &ppp_net_id,
1170         .size = sizeof(struct ppp_net),
1171 };
1172
1173 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1174 {
1175         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1176         int ret;
1177
1178         mutex_lock(&pn->all_ppp_mutex);
1179
1180         if (unit < 0) {
1181                 ret = unit_get(&pn->units_idr, ppp, 0);
1182                 if (ret < 0)
1183                         goto err;
1184                 if (!ifname_is_set) {
1185                         while (1) {
1186                                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1187                                 if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
1188                                         break;
1189                                 unit_put(&pn->units_idr, ret);
1190                                 ret = unit_get(&pn->units_idr, ppp, ret + 1);
1191                                 if (ret < 0)
1192                                         goto err;
1193                         }
1194                 }
1195         } else {
1196                 /* Caller asked for a specific unit number. Fail with -EEXIST
1197                  * if unavailable. For backward compatibility, return -EEXIST
1198                  * too if idr allocation fails; this makes pppd retry without
1199                  * requesting a specific unit number.
1200                  */
1201                 if (unit_find(&pn->units_idr, unit)) {
1202                         ret = -EEXIST;
1203                         goto err;
1204                 }
1205                 ret = unit_set(&pn->units_idr, ppp, unit);
1206                 if (ret < 0) {
1207                         /* Rewrite error for backward compatibility */
1208                         ret = -EEXIST;
1209                         goto err;
1210                 }
1211         }
1212         ppp->file.index = ret;
1213
1214         if (!ifname_is_set)
1215                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1216
1217         mutex_unlock(&pn->all_ppp_mutex);
1218
1219         ret = register_netdevice(ppp->dev);
1220         if (ret < 0)
1221                 goto err_unit;
1222
1223         atomic_inc(&ppp_unit_count);
1224
1225         return 0;
1226
1227 err_unit:
1228         mutex_lock(&pn->all_ppp_mutex);
1229         unit_put(&pn->units_idr, ppp->file.index);
1230 err:
1231         mutex_unlock(&pn->all_ppp_mutex);
1232
1233         return ret;
1234 }
1235
1236 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1237                              const struct ppp_config *conf)
1238 {
1239         struct ppp *ppp = netdev_priv(dev);
1240         int indx;
1241         int err;
1242         int cpu;
1243
1244         ppp->dev = dev;
1245         ppp->ppp_net = src_net;
1246         ppp->mru = PPP_MRU;
1247         ppp->owner = conf->file;
1248
1249         init_ppp_file(&ppp->file, INTERFACE);
1250         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1251
1252         for (indx = 0; indx < NUM_NP; ++indx)
1253                 ppp->npmode[indx] = NPMODE_PASS;
1254         INIT_LIST_HEAD(&ppp->channels);
1255         spin_lock_init(&ppp->rlock);
1256         spin_lock_init(&ppp->wlock);
1257
1258         ppp->xmit_recursion = alloc_percpu(int);
1259         if (!ppp->xmit_recursion) {
1260                 err = -ENOMEM;
1261                 goto err1;
1262         }
1263         for_each_possible_cpu(cpu)
1264                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1265
1266 #ifdef CONFIG_PPP_MULTILINK
1267         ppp->minseq = -1;
1268         skb_queue_head_init(&ppp->mrq);
1269 #endif /* CONFIG_PPP_MULTILINK */
1270 #ifdef CONFIG_PPP_FILTER
1271         ppp->pass_filter = NULL;
1272         ppp->active_filter = NULL;
1273 #endif /* CONFIG_PPP_FILTER */
1274
1275         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1276         if (err < 0)
1277                 goto err2;
1278
1279         conf->file->private_data = &ppp->file;
1280
1281         return 0;
1282 err2:
1283         free_percpu(ppp->xmit_recursion);
1284 err1:
1285         return err;
1286 }
1287
1288 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1289         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1290 };
1291
1292 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1293                            struct netlink_ext_ack *extack)
1294 {
1295         if (!data)
1296                 return -EINVAL;
1297
1298         if (!data[IFLA_PPP_DEV_FD])
1299                 return -EINVAL;
1300         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1301                 return -EBADF;
1302
1303         return 0;
1304 }
1305
1306 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1307                           struct nlattr *tb[], struct nlattr *data[],
1308                           struct netlink_ext_ack *extack)
1309 {
1310         struct ppp_config conf = {
1311                 .unit = -1,
1312                 .ifname_is_set = true,
1313         };
1314         struct file *file;
1315         int err;
1316
1317         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1318         if (!file)
1319                 return -EBADF;
1320
1321         /* rtnl_lock is already held here, but ppp_create_interface() locks
1322          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1323          * possible deadlock due to lock order inversion, at the cost of
1324          * pushing the problem back to userspace.
1325          */
1326         if (!mutex_trylock(&ppp_mutex)) {
1327                 err = -EBUSY;
1328                 goto out;
1329         }
1330
1331         if (file->f_op != &ppp_device_fops || file->private_data) {
1332                 err = -EBADF;
1333                 goto out_unlock;
1334         }
1335
1336         conf.file = file;
1337
1338         /* Don't use device name generated by the rtnetlink layer when ifname
1339          * isn't specified. Let ppp_dev_configure() set the device name using
1340          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1341          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1342          */
1343         if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1344                 conf.ifname_is_set = false;
1345
1346         err = ppp_dev_configure(src_net, dev, &conf);
1347
1348 out_unlock:
1349         mutex_unlock(&ppp_mutex);
1350 out:
1351         fput(file);
1352
1353         return err;
1354 }
1355
1356 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1357 {
1358         unregister_netdevice_queue(dev, head);
1359 }
1360
1361 static size_t ppp_nl_get_size(const struct net_device *dev)
1362 {
1363         return 0;
1364 }
1365
1366 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1367 {
1368         return 0;
1369 }
1370
1371 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1372 {
1373         struct ppp *ppp = netdev_priv(dev);
1374
1375         return READ_ONCE(ppp->ppp_net);
1376 }
1377
1378 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1379         .kind           = "ppp",
1380         .maxtype        = IFLA_PPP_MAX,
1381         .policy         = ppp_nl_policy,
1382         .priv_size      = sizeof(struct ppp),
1383         .setup          = ppp_setup,
1384         .validate       = ppp_nl_validate,
1385         .newlink        = ppp_nl_newlink,
1386         .dellink        = ppp_nl_dellink,
1387         .get_size       = ppp_nl_get_size,
1388         .fill_info      = ppp_nl_fill_info,
1389         .get_link_net   = ppp_nl_get_link_net,
1390 };
1391
1392 #define PPP_MAJOR       108
1393
1394 /* Called at boot time if ppp is compiled into the kernel,
1395    or at module load time (from init_module) if compiled as a module. */
1396 static int __init ppp_init(void)
1397 {
1398         int err;
1399
1400         pr_info("PPP generic driver version " PPP_VERSION "\n");
1401
1402         err = register_pernet_device(&ppp_net_ops);
1403         if (err) {
1404                 pr_err("failed to register PPP pernet device (%d)\n", err);
1405                 goto out;
1406         }
1407
1408         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1409         if (err) {
1410                 pr_err("failed to register PPP device (%d)\n", err);
1411                 goto out_net;
1412         }
1413
1414         err = class_register(&ppp_class);
1415         if (err)
1416                 goto out_chrdev;
1417
1418         err = rtnl_link_register(&ppp_link_ops);
1419         if (err) {
1420                 pr_err("failed to register rtnetlink PPP handler\n");
1421                 goto out_class;
1422         }
1423
1424         /* not a big deal if we fail here :-) */
1425         device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1426
1427         return 0;
1428
1429 out_class:
1430         class_unregister(&ppp_class);
1431 out_chrdev:
1432         unregister_chrdev(PPP_MAJOR, "ppp");
1433 out_net:
1434         unregister_pernet_device(&ppp_net_ops);
1435 out:
1436         return err;
1437 }
1438
1439 /*
1440  * Network interface unit routines.
1441  */
1442 static netdev_tx_t
1443 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1444 {
1445         struct ppp *ppp = netdev_priv(dev);
1446         int npi, proto;
1447         unsigned char *pp;
1448
1449         npi = ethertype_to_npindex(ntohs(skb->protocol));
1450         if (npi < 0)
1451                 goto outf;
1452
1453         /* Drop, accept or reject the packet */
1454         switch (ppp->npmode[npi]) {
1455         case NPMODE_PASS:
1456                 break;
1457         case NPMODE_QUEUE:
1458                 /* it would be nice to have a way to tell the network
1459                    system to queue this one up for later. */
1460                 goto outf;
1461         case NPMODE_DROP:
1462         case NPMODE_ERROR:
1463                 goto outf;
1464         }
1465
1466         /* Put the 2-byte PPP protocol number on the front,
1467            making sure there is room for the address and control fields. */
1468         if (skb_cow_head(skb, PPP_HDRLEN))
1469                 goto outf;
1470
1471         pp = skb_push(skb, 2);
1472         proto = npindex_to_proto[npi];
1473         put_unaligned_be16(proto, pp);
1474
1475         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1476         ppp_xmit_process(ppp, skb);
1477
1478         return NETDEV_TX_OK;
1479
1480  outf:
1481         kfree_skb(skb);
1482         ++dev->stats.tx_dropped;
1483         return NETDEV_TX_OK;
1484 }
1485
1486 static int
1487 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1488                        void __user *addr, int cmd)
1489 {
1490         struct ppp *ppp = netdev_priv(dev);
1491         int err = -EFAULT;
1492         struct ppp_stats stats;
1493         struct ppp_comp_stats cstats;
1494         char *vers;
1495
1496         switch (cmd) {
1497         case SIOCGPPPSTATS:
1498                 ppp_get_stats(ppp, &stats);
1499                 if (copy_to_user(addr, &stats, sizeof(stats)))
1500                         break;
1501                 err = 0;
1502                 break;
1503
1504         case SIOCGPPPCSTATS:
1505                 memset(&cstats, 0, sizeof(cstats));
1506                 if (ppp->xc_state)
1507                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1508                 if (ppp->rc_state)
1509                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1510                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1511                         break;
1512                 err = 0;
1513                 break;
1514
1515         case SIOCGPPPVER:
1516                 vers = PPP_VERSION;
1517                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1518                         break;
1519                 err = 0;
1520                 break;
1521
1522         default:
1523                 err = -EINVAL;
1524         }
1525
1526         return err;
1527 }
1528
1529 static void
1530 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1531 {
1532         struct ppp *ppp = netdev_priv(dev);
1533
1534         ppp_recv_lock(ppp);
1535         stats64->rx_packets = ppp->stats64.rx_packets;
1536         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1537         ppp_recv_unlock(ppp);
1538
1539         ppp_xmit_lock(ppp);
1540         stats64->tx_packets = ppp->stats64.tx_packets;
1541         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1542         ppp_xmit_unlock(ppp);
1543
1544         stats64->rx_errors        = dev->stats.rx_errors;
1545         stats64->tx_errors        = dev->stats.tx_errors;
1546         stats64->rx_dropped       = dev->stats.rx_dropped;
1547         stats64->tx_dropped       = dev->stats.tx_dropped;
1548         stats64->rx_length_errors = dev->stats.rx_length_errors;
1549 }
1550
1551 static int ppp_dev_init(struct net_device *dev)
1552 {
1553         struct ppp *ppp;
1554
1555         netdev_lockdep_set_classes(dev);
1556
1557         ppp = netdev_priv(dev);
1558         /* Let the netdevice take a reference on the ppp file. This ensures
1559          * that ppp_destroy_interface() won't run before the device gets
1560          * unregistered.
1561          */
1562         refcount_inc(&ppp->file.refcnt);
1563
1564         return 0;
1565 }
1566
1567 static void ppp_dev_uninit(struct net_device *dev)
1568 {
1569         struct ppp *ppp = netdev_priv(dev);
1570         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1571
1572         ppp_lock(ppp);
1573         ppp->closing = 1;
1574         ppp_unlock(ppp);
1575
1576         mutex_lock(&pn->all_ppp_mutex);
1577         unit_put(&pn->units_idr, ppp->file.index);
1578         mutex_unlock(&pn->all_ppp_mutex);
1579
1580         ppp->owner = NULL;
1581
1582         ppp->file.dead = 1;
1583         wake_up_interruptible(&ppp->file.rwait);
1584 }
1585
1586 static void ppp_dev_priv_destructor(struct net_device *dev)
1587 {
1588         struct ppp *ppp;
1589
1590         ppp = netdev_priv(dev);
1591         if (refcount_dec_and_test(&ppp->file.refcnt))
1592                 ppp_destroy_interface(ppp);
1593 }
1594
1595 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1596                                  struct net_device_path *path)
1597 {
1598         struct ppp *ppp = netdev_priv(ctx->dev);
1599         struct ppp_channel *chan;
1600         struct channel *pch;
1601
1602         if (ppp->flags & SC_MULTILINK)
1603                 return -EOPNOTSUPP;
1604
1605         if (list_empty(&ppp->channels))
1606                 return -ENODEV;
1607
1608         pch = list_first_entry(&ppp->channels, struct channel, clist);
1609         chan = pch->chan;
1610         if (!chan->ops->fill_forward_path)
1611                 return -EOPNOTSUPP;
1612
1613         return chan->ops->fill_forward_path(ctx, path, chan);
1614 }
1615
1616 static const struct net_device_ops ppp_netdev_ops = {
1617         .ndo_init        = ppp_dev_init,
1618         .ndo_uninit      = ppp_dev_uninit,
1619         .ndo_start_xmit  = ppp_start_xmit,
1620         .ndo_siocdevprivate = ppp_net_siocdevprivate,
1621         .ndo_get_stats64 = ppp_get_stats64,
1622         .ndo_fill_forward_path = ppp_fill_forward_path,
1623 };
1624
1625 static const struct device_type ppp_type = {
1626         .name = "ppp",
1627 };
1628
1629 static void ppp_setup(struct net_device *dev)
1630 {
1631         dev->netdev_ops = &ppp_netdev_ops;
1632         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1633
1634         dev->lltx = true;
1635
1636         dev->hard_header_len = PPP_HDRLEN;
1637         dev->mtu = PPP_MRU;
1638         dev->addr_len = 0;
1639         dev->tx_queue_len = 3;
1640         dev->type = ARPHRD_PPP;
1641         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1642         dev->priv_destructor = ppp_dev_priv_destructor;
1643         netif_keep_dst(dev);
1644 }
1645
1646 /*
1647  * Transmit-side routines.
1648  */
1649
1650 /* Called to do any work queued up on the transmit side that can now be done */
1651 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1652 {
1653         ppp_xmit_lock(ppp);
1654         if (!ppp->closing) {
1655                 ppp_push(ppp);
1656
1657                 if (skb)
1658                         skb_queue_tail(&ppp->file.xq, skb);
1659                 while (!ppp->xmit_pending &&
1660                        (skb = skb_dequeue(&ppp->file.xq)))
1661                         ppp_send_frame(ppp, skb);
1662                 /* If there's no work left to do, tell the core net
1663                    code that we can accept some more. */
1664                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1665                         netif_wake_queue(ppp->dev);
1666                 else
1667                         netif_stop_queue(ppp->dev);
1668         } else {
1669                 kfree_skb(skb);
1670         }
1671         ppp_xmit_unlock(ppp);
1672 }
1673
1674 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1675 {
1676         local_bh_disable();
1677
1678         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1679                 goto err;
1680
1681         (*this_cpu_ptr(ppp->xmit_recursion))++;
1682         __ppp_xmit_process(ppp, skb);
1683         (*this_cpu_ptr(ppp->xmit_recursion))--;
1684
1685         local_bh_enable();
1686
1687         return;
1688
1689 err:
1690         local_bh_enable();
1691
1692         kfree_skb(skb);
1693
1694         if (net_ratelimit())
1695                 netdev_err(ppp->dev, "recursion detected\n");
1696 }
1697
1698 static inline struct sk_buff *
1699 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1700 {
1701         struct sk_buff *new_skb;
1702         int len;
1703         int new_skb_size = ppp->dev->mtu +
1704                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1705         int compressor_skb_size = ppp->dev->mtu +
1706                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1707         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1708         if (!new_skb) {
1709                 if (net_ratelimit())
1710                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1711                 return NULL;
1712         }
1713         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1714                 skb_reserve(new_skb,
1715                             ppp->dev->hard_header_len - PPP_HDRLEN);
1716
1717         /* compressor still expects A/C bytes in hdr */
1718         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1719                                    new_skb->data, skb->len + 2,
1720                                    compressor_skb_size);
1721         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1722                 consume_skb(skb);
1723                 skb = new_skb;
1724                 skb_put(skb, len);
1725                 skb_pull(skb, 2);       /* pull off A/C bytes */
1726         } else if (len == 0) {
1727                 /* didn't compress, or CCP not up yet */
1728                 consume_skb(new_skb);
1729                 new_skb = skb;
1730         } else {
1731                 /*
1732                  * (len < 0)
1733                  * MPPE requires that we do not send unencrypted
1734                  * frames.  The compressor will return -1 if we
1735                  * should drop the frame.  We cannot simply test
1736                  * the compress_proto because MPPE and MPPC share
1737                  * the same number.
1738                  */
1739                 if (net_ratelimit())
1740                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1741                 kfree_skb(skb);
1742                 consume_skb(new_skb);
1743                 new_skb = NULL;
1744         }
1745         return new_skb;
1746 }
1747
1748 /*
1749  * Compress and send a frame.
1750  * The caller should have locked the xmit path,
1751  * and xmit_pending should be 0.
1752  */
1753 static void
1754 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1755 {
1756         int proto = PPP_PROTO(skb);
1757         struct sk_buff *new_skb;
1758         int len;
1759         unsigned char *cp;
1760
1761         skb->dev = ppp->dev;
1762
1763         if (proto < 0x8000) {
1764 #ifdef CONFIG_PPP_FILTER
1765                 /* check if we should pass this packet */
1766                 /* the filter instructions are constructed assuming
1767                    a four-byte PPP header on each packet */
1768                 *(u8 *)skb_push(skb, 2) = 1;
1769                 if (ppp->pass_filter &&
1770                     bpf_prog_run(ppp->pass_filter, skb) == 0) {
1771                         if (ppp->debug & 1)
1772                                 netdev_printk(KERN_DEBUG, ppp->dev,
1773                                               "PPP: outbound frame "
1774                                               "not passed\n");
1775                         kfree_skb(skb);
1776                         return;
1777                 }
1778                 /* if this packet passes the active filter, record the time */
1779                 if (!(ppp->active_filter &&
1780                       bpf_prog_run(ppp->active_filter, skb) == 0))
1781                         ppp->last_xmit = jiffies;
1782                 skb_pull(skb, 2);
1783 #else
1784                 /* for data packets, record the time */
1785                 ppp->last_xmit = jiffies;
1786 #endif /* CONFIG_PPP_FILTER */
1787         }
1788
1789         ++ppp->stats64.tx_packets;
1790         ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1791
1792         switch (proto) {
1793         case PPP_IP:
1794                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1795                         break;
1796                 /* try to do VJ TCP header compression */
1797                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1798                                     GFP_ATOMIC);
1799                 if (!new_skb) {
1800                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1801                         goto drop;
1802                 }
1803                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1804                 cp = skb->data + 2;
1805                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1806                                     new_skb->data + 2, &cp,
1807                                     !(ppp->flags & SC_NO_TCP_CCID));
1808                 if (cp == skb->data + 2) {
1809                         /* didn't compress */
1810                         consume_skb(new_skb);
1811                 } else {
1812                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1813                                 proto = PPP_VJC_COMP;
1814                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1815                         } else {
1816                                 proto = PPP_VJC_UNCOMP;
1817                                 cp[0] = skb->data[2];
1818                         }
1819                         consume_skb(skb);
1820                         skb = new_skb;
1821                         cp = skb_put(skb, len + 2);
1822                         cp[0] = 0;
1823                         cp[1] = proto;
1824                 }
1825                 break;
1826
1827         case PPP_CCP:
1828                 /* peek at outbound CCP frames */
1829                 ppp_ccp_peek(ppp, skb, 0);
1830                 break;
1831         }
1832
1833         /* try to do packet compression */
1834         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1835             proto != PPP_LCP && proto != PPP_CCP) {
1836                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1837                         if (net_ratelimit())
1838                                 netdev_err(ppp->dev,
1839                                            "ppp: compression required but "
1840                                            "down - pkt dropped.\n");
1841                         goto drop;
1842                 }
1843                 skb = pad_compress_skb(ppp, skb);
1844                 if (!skb)
1845                         goto drop;
1846         }
1847
1848         /*
1849          * If we are waiting for traffic (demand dialling),
1850          * queue it up for pppd to receive.
1851          */
1852         if (ppp->flags & SC_LOOP_TRAFFIC) {
1853                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1854                         goto drop;
1855                 skb_queue_tail(&ppp->file.rq, skb);
1856                 wake_up_interruptible(&ppp->file.rwait);
1857                 return;
1858         }
1859
1860         ppp->xmit_pending = skb;
1861         ppp_push(ppp);
1862         return;
1863
1864  drop:
1865         kfree_skb(skb);
1866         ++ppp->dev->stats.tx_errors;
1867 }
1868
1869 /*
1870  * Try to send the frame in xmit_pending.
1871  * The caller should have the xmit path locked.
1872  */
1873 static void
1874 ppp_push(struct ppp *ppp)
1875 {
1876         struct list_head *list;
1877         struct channel *pch;
1878         struct sk_buff *skb = ppp->xmit_pending;
1879
1880         if (!skb)
1881                 return;
1882
1883         list = &ppp->channels;
1884         if (list_empty(list)) {
1885                 /* nowhere to send the packet, just drop it */
1886                 ppp->xmit_pending = NULL;
1887                 kfree_skb(skb);
1888                 return;
1889         }
1890
1891         if ((ppp->flags & SC_MULTILINK) == 0) {
1892                 /* not doing multilink: send it down the first channel */
1893                 list = list->next;
1894                 pch = list_entry(list, struct channel, clist);
1895
1896                 spin_lock(&pch->downl);
1897                 if (pch->chan) {
1898                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1899                                 ppp->xmit_pending = NULL;
1900                 } else {
1901                         /* channel got unregistered */
1902                         kfree_skb(skb);
1903                         ppp->xmit_pending = NULL;
1904                 }
1905                 spin_unlock(&pch->downl);
1906                 return;
1907         }
1908
1909 #ifdef CONFIG_PPP_MULTILINK
1910         /* Multilink: fragment the packet over as many links
1911            as can take the packet at the moment. */
1912         if (!ppp_mp_explode(ppp, skb))
1913                 return;
1914 #endif /* CONFIG_PPP_MULTILINK */
1915
1916         ppp->xmit_pending = NULL;
1917         kfree_skb(skb);
1918 }
1919
1920 #ifdef CONFIG_PPP_MULTILINK
1921 static bool mp_protocol_compress __read_mostly = true;
1922 module_param(mp_protocol_compress, bool, 0644);
1923 MODULE_PARM_DESC(mp_protocol_compress,
1924                  "compress protocol id in multilink fragments");
1925
1926 /*
1927  * Divide a packet to be transmitted into fragments and
1928  * send them out the individual links.
1929  */
1930 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1931 {
1932         int len, totlen;
1933         int i, bits, hdrlen, mtu;
1934         int flen;
1935         int navail, nfree, nzero;
1936         int nbigger;
1937         int totspeed;
1938         int totfree;
1939         unsigned char *p, *q;
1940         struct list_head *list;
1941         struct channel *pch;
1942         struct sk_buff *frag;
1943         struct ppp_channel *chan;
1944
1945         totspeed = 0; /*total bitrate of the bundle*/
1946         nfree = 0; /* # channels which have no packet already queued */
1947         navail = 0; /* total # of usable channels (not deregistered) */
1948         nzero = 0; /* number of channels with zero speed associated*/
1949         totfree = 0; /*total # of channels available and
1950                                   *having no queued packets before
1951                                   *starting the fragmentation*/
1952
1953         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1954         i = 0;
1955         list_for_each_entry(pch, &ppp->channels, clist) {
1956                 if (pch->chan) {
1957                         pch->avail = 1;
1958                         navail++;
1959                         pch->speed = pch->chan->speed;
1960                 } else {
1961                         pch->avail = 0;
1962                 }
1963                 if (pch->avail) {
1964                         if (skb_queue_empty(&pch->file.xq) ||
1965                                 !pch->had_frag) {
1966                                         if (pch->speed == 0)
1967                                                 nzero++;
1968                                         else
1969                                                 totspeed += pch->speed;
1970
1971                                         pch->avail = 2;
1972                                         ++nfree;
1973                                         ++totfree;
1974                                 }
1975                         if (!pch->had_frag && i < ppp->nxchan)
1976                                 ppp->nxchan = i;
1977                 }
1978                 ++i;
1979         }
1980         /*
1981          * Don't start sending this packet unless at least half of
1982          * the channels are free.  This gives much better TCP
1983          * performance if we have a lot of channels.
1984          */
1985         if (nfree == 0 || nfree < navail / 2)
1986                 return 0; /* can't take now, leave it in xmit_pending */
1987
1988         /* Do protocol field compression */
1989         p = skb->data;
1990         len = skb->len;
1991         if (*p == 0 && mp_protocol_compress) {
1992                 ++p;
1993                 --len;
1994         }
1995
1996         totlen = len;
1997         nbigger = len % nfree;
1998
1999         /* skip to the channel after the one we last used
2000            and start at that one */
2001         list = &ppp->channels;
2002         for (i = 0; i < ppp->nxchan; ++i) {
2003                 list = list->next;
2004                 if (list == &ppp->channels) {
2005                         i = 0;
2006                         break;
2007                 }
2008         }
2009
2010         /* create a fragment for each channel */
2011         bits = B;
2012         while (len > 0) {
2013                 list = list->next;
2014                 if (list == &ppp->channels) {
2015                         i = 0;
2016                         continue;
2017                 }
2018                 pch = list_entry(list, struct channel, clist);
2019                 ++i;
2020                 if (!pch->avail)
2021                         continue;
2022
2023                 /*
2024                  * Skip this channel if it has a fragment pending already and
2025                  * we haven't given a fragment to all of the free channels.
2026                  */
2027                 if (pch->avail == 1) {
2028                         if (nfree > 0)
2029                                 continue;
2030                 } else {
2031                         pch->avail = 1;
2032                 }
2033
2034                 /* check the channel's mtu and whether it is still attached. */
2035                 spin_lock(&pch->downl);
2036                 if (pch->chan == NULL) {
2037                         /* can't use this channel, it's being deregistered */
2038                         if (pch->speed == 0)
2039                                 nzero--;
2040                         else
2041                                 totspeed -= pch->speed;
2042
2043                         spin_unlock(&pch->downl);
2044                         pch->avail = 0;
2045                         totlen = len;
2046                         totfree--;
2047                         nfree--;
2048                         if (--navail == 0)
2049                                 break;
2050                         continue;
2051                 }
2052
2053                 /*
2054                 *if the channel speed is not set divide
2055                 *the packet evenly among the free channels;
2056                 *otherwise divide it according to the speed
2057                 *of the channel we are going to transmit on
2058                 */
2059                 flen = len;
2060                 if (nfree > 0) {
2061                         if (pch->speed == 0) {
2062                                 flen = len/nfree;
2063                                 if (nbigger > 0) {
2064                                         flen++;
2065                                         nbigger--;
2066                                 }
2067                         } else {
2068                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2069                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
2070                                 if (nbigger > 0) {
2071                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
2072                                         nbigger -= ((totfree - nzero)*pch->speed)/
2073                                                         totspeed;
2074                                 }
2075                         }
2076                         nfree--;
2077                 }
2078
2079                 /*
2080                  *check if we are on the last channel or
2081                  *we exceded the length of the data to
2082                  *fragment
2083                  */
2084                 if ((nfree <= 0) || (flen > len))
2085                         flen = len;
2086                 /*
2087                  *it is not worth to tx on slow channels:
2088                  *in that case from the resulting flen according to the
2089                  *above formula will be equal or less than zero.
2090                  *Skip the channel in this case
2091                  */
2092                 if (flen <= 0) {
2093                         pch->avail = 2;
2094                         spin_unlock(&pch->downl);
2095                         continue;
2096                 }
2097
2098                 /*
2099                  * hdrlen includes the 2-byte PPP protocol field, but the
2100                  * MTU counts only the payload excluding the protocol field.
2101                  * (RFC1661 Section 2)
2102                  */
2103                 mtu = pch->chan->mtu - (hdrlen - 2);
2104                 if (mtu < 4)
2105                         mtu = 4;
2106                 if (flen > mtu)
2107                         flen = mtu;
2108                 if (flen == len)
2109                         bits |= E;
2110                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2111                 if (!frag)
2112                         goto noskb;
2113                 q = skb_put(frag, flen + hdrlen);
2114
2115                 /* make the MP header */
2116                 put_unaligned_be16(PPP_MP, q);
2117                 if (ppp->flags & SC_MP_XSHORTSEQ) {
2118                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2119                         q[3] = ppp->nxseq;
2120                 } else {
2121                         q[2] = bits;
2122                         q[3] = ppp->nxseq >> 16;
2123                         q[4] = ppp->nxseq >> 8;
2124                         q[5] = ppp->nxseq;
2125                 }
2126
2127                 memcpy(q + hdrlen, p, flen);
2128
2129                 /* try to send it down the channel */
2130                 chan = pch->chan;
2131                 if (!skb_queue_empty(&pch->file.xq) ||
2132                         !chan->ops->start_xmit(chan, frag))
2133                         skb_queue_tail(&pch->file.xq, frag);
2134                 pch->had_frag = 1;
2135                 p += flen;
2136                 len -= flen;
2137                 ++ppp->nxseq;
2138                 bits = 0;
2139                 spin_unlock(&pch->downl);
2140         }
2141         ppp->nxchan = i;
2142
2143         return 1;
2144
2145  noskb:
2146         spin_unlock(&pch->downl);
2147         if (ppp->debug & 1)
2148                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2149         ++ppp->dev->stats.tx_errors;
2150         ++ppp->nxseq;
2151         return 1;       /* abandon the frame */
2152 }
2153 #endif /* CONFIG_PPP_MULTILINK */
2154
2155 /* Try to send data out on a channel */
2156 static void __ppp_channel_push(struct channel *pch)
2157 {
2158         struct sk_buff *skb;
2159         struct ppp *ppp;
2160
2161         spin_lock(&pch->downl);
2162         if (pch->chan) {
2163                 while (!skb_queue_empty(&pch->file.xq)) {
2164                         skb = skb_dequeue(&pch->file.xq);
2165                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2166                                 /* put the packet back and try again later */
2167                                 skb_queue_head(&pch->file.xq, skb);
2168                                 break;
2169                         }
2170                 }
2171         } else {
2172                 /* channel got deregistered */
2173                 skb_queue_purge(&pch->file.xq);
2174         }
2175         spin_unlock(&pch->downl);
2176         /* see if there is anything from the attached unit to be sent */
2177         if (skb_queue_empty(&pch->file.xq)) {
2178                 ppp = pch->ppp;
2179                 if (ppp)
2180                         __ppp_xmit_process(ppp, NULL);
2181         }
2182 }
2183
2184 static void ppp_channel_push(struct channel *pch)
2185 {
2186         read_lock_bh(&pch->upl);
2187         if (pch->ppp) {
2188                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2189                 __ppp_channel_push(pch);
2190                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2191         } else {
2192                 __ppp_channel_push(pch);
2193         }
2194         read_unlock_bh(&pch->upl);
2195 }
2196
2197 /*
2198  * Receive-side routines.
2199  */
2200
2201 struct ppp_mp_skb_parm {
2202         u32             sequence;
2203         u8              BEbits;
2204 };
2205 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
2206
2207 static inline void
2208 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2209 {
2210         ppp_recv_lock(ppp);
2211         if (!ppp->closing)
2212                 ppp_receive_frame(ppp, skb, pch);
2213         else
2214                 kfree_skb(skb);
2215         ppp_recv_unlock(ppp);
2216 }
2217
2218 /**
2219  * __ppp_decompress_proto - Decompress protocol field, slim version.
2220  * @skb: Socket buffer where protocol field should be decompressed. It must have
2221  *       at least 1 byte of head room and 1 byte of linear data. First byte of
2222  *       data must be a protocol field byte.
2223  *
2224  * Decompress protocol field in PPP header if it's compressed, e.g. when
2225  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2226  * length are done in this function.
2227  */
2228 static void __ppp_decompress_proto(struct sk_buff *skb)
2229 {
2230         if (skb->data[0] & 0x01)
2231                 *(u8 *)skb_push(skb, 1) = 0x00;
2232 }
2233
2234 /**
2235  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2236  * @skb: Socket buffer where protocol field should be decompressed. First byte
2237  *       of data must be a protocol field byte.
2238  *
2239  * Decompress protocol field in PPP header if it's compressed, e.g. when
2240  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2241  * sure that skb data room is sufficient for Protocol field, before and after
2242  * decompression.
2243  *
2244  * Return: true - decompressed successfully, false - not enough room in skb.
2245  */
2246 static bool ppp_decompress_proto(struct sk_buff *skb)
2247 {
2248         /* At least one byte should be present (if protocol is compressed) */
2249         if (!pskb_may_pull(skb, 1))
2250                 return false;
2251
2252         __ppp_decompress_proto(skb);
2253
2254         /* Protocol field should occupy 2 bytes when not compressed */
2255         return pskb_may_pull(skb, 2);
2256 }
2257
2258 /* Attempt to handle a frame via. a bridged channel, if one exists.
2259  * If the channel is bridged, the frame is consumed by the bridge.
2260  * If not, the caller must handle the frame by normal recv mechanisms.
2261  * Returns true if the frame is consumed, false otherwise.
2262  */
2263 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2264 {
2265         struct channel *pchb;
2266
2267         rcu_read_lock();
2268         pchb = rcu_dereference(pch->bridge);
2269         if (!pchb)
2270                 goto out_rcu;
2271
2272         spin_lock_bh(&pchb->downl);
2273         if (!pchb->chan) {
2274                 /* channel got unregistered */
2275                 kfree_skb(skb);
2276                 goto outl;
2277         }
2278
2279         skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2280         if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2281                 kfree_skb(skb);
2282
2283 outl:
2284         spin_unlock_bh(&pchb->downl);
2285 out_rcu:
2286         rcu_read_unlock();
2287
2288         /* If pchb is set then we've consumed the packet */
2289         return !!pchb;
2290 }
2291
2292 void
2293 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2294 {
2295         struct channel *pch = chan->ppp;
2296         int proto;
2297
2298         if (!pch) {
2299                 kfree_skb(skb);
2300                 return;
2301         }
2302
2303         /* If the channel is bridged, transmit via. bridge */
2304         if (ppp_channel_bridge_input(pch, skb))
2305                 return;
2306
2307         read_lock_bh(&pch->upl);
2308         if (!ppp_decompress_proto(skb)) {
2309                 kfree_skb(skb);
2310                 if (pch->ppp) {
2311                         ++pch->ppp->dev->stats.rx_length_errors;
2312                         ppp_receive_error(pch->ppp);
2313                 }
2314                 goto done;
2315         }
2316
2317         proto = PPP_PROTO(skb);
2318         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2319                 /* put it on the channel queue */
2320                 skb_queue_tail(&pch->file.rq, skb);
2321                 /* drop old frames if queue too long */
2322                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2323                        (skb = skb_dequeue(&pch->file.rq)))
2324                         kfree_skb(skb);
2325                 wake_up_interruptible(&pch->file.rwait);
2326         } else {
2327                 ppp_do_recv(pch->ppp, skb, pch);
2328         }
2329
2330 done:
2331         read_unlock_bh(&pch->upl);
2332 }
2333
2334 /* Put a 0-length skb in the receive queue as an error indication */
2335 void
2336 ppp_input_error(struct ppp_channel *chan, int code)
2337 {
2338         struct channel *pch = chan->ppp;
2339         struct sk_buff *skb;
2340
2341         if (!pch)
2342                 return;
2343
2344         read_lock_bh(&pch->upl);
2345         if (pch->ppp) {
2346                 skb = alloc_skb(0, GFP_ATOMIC);
2347                 if (skb) {
2348                         skb->len = 0;           /* probably unnecessary */
2349                         skb->cb[0] = code;
2350                         ppp_do_recv(pch->ppp, skb, pch);
2351                 }
2352         }
2353         read_unlock_bh(&pch->upl);
2354 }
2355
2356 /*
2357  * We come in here to process a received frame.
2358  * The receive side of the ppp unit is locked.
2359  */
2360 static void
2361 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2362 {
2363         /* note: a 0-length skb is used as an error indication */
2364         if (skb->len > 0) {
2365                 skb_checksum_complete_unset(skb);
2366 #ifdef CONFIG_PPP_MULTILINK
2367                 /* XXX do channel-level decompression here */
2368                 if (PPP_PROTO(skb) == PPP_MP)
2369                         ppp_receive_mp_frame(ppp, skb, pch);
2370                 else
2371 #endif /* CONFIG_PPP_MULTILINK */
2372                         ppp_receive_nonmp_frame(ppp, skb);
2373         } else {
2374                 kfree_skb(skb);
2375                 ppp_receive_error(ppp);
2376         }
2377 }
2378
2379 static void
2380 ppp_receive_error(struct ppp *ppp)
2381 {
2382         ++ppp->dev->stats.rx_errors;
2383         if (ppp->vj)
2384                 slhc_toss(ppp->vj);
2385 }
2386
2387 static void
2388 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2389 {
2390         struct sk_buff *ns;
2391         int proto, len, npi;
2392
2393         /*
2394          * Decompress the frame, if compressed.
2395          * Note that some decompressors need to see uncompressed frames
2396          * that come in as well as compressed frames.
2397          */
2398         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2399             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2400                 skb = ppp_decompress_frame(ppp, skb);
2401
2402         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2403                 goto err;
2404
2405         /* At this point the "Protocol" field MUST be decompressed, either in
2406          * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2407          */
2408         proto = PPP_PROTO(skb);
2409         switch (proto) {
2410         case PPP_VJC_COMP:
2411                 /* decompress VJ compressed packets */
2412                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2413                         goto err;
2414
2415                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2416                         /* copy to a new sk_buff with more tailroom */
2417                         ns = dev_alloc_skb(skb->len + 128);
2418                         if (!ns) {
2419                                 netdev_err(ppp->dev, "PPP: no memory "
2420                                            "(VJ decomp)\n");
2421                                 goto err;
2422                         }
2423                         skb_reserve(ns, 2);
2424                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2425                         consume_skb(skb);
2426                         skb = ns;
2427                 }
2428                 else
2429                         skb->ip_summed = CHECKSUM_NONE;
2430
2431                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2432                 if (len <= 0) {
2433                         netdev_printk(KERN_DEBUG, ppp->dev,
2434                                       "PPP: VJ decompression error\n");
2435                         goto err;
2436                 }
2437                 len += 2;
2438                 if (len > skb->len)
2439                         skb_put(skb, len - skb->len);
2440                 else if (len < skb->len)
2441                         skb_trim(skb, len);
2442                 proto = PPP_IP;
2443                 break;
2444
2445         case PPP_VJC_UNCOMP:
2446                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2447                         goto err;
2448
2449                 /* Until we fix the decompressor need to make sure
2450                  * data portion is linear.
2451                  */
2452                 if (!pskb_may_pull(skb, skb->len))
2453                         goto err;
2454
2455                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2456                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2457                         goto err;
2458                 }
2459                 proto = PPP_IP;
2460                 break;
2461
2462         case PPP_CCP:
2463                 ppp_ccp_peek(ppp, skb, 1);
2464                 break;
2465         }
2466
2467         ++ppp->stats64.rx_packets;
2468         ppp->stats64.rx_bytes += skb->len - 2;
2469
2470         npi = proto_to_npindex(proto);
2471         if (npi < 0) {
2472                 /* control or unknown frame - pass it to pppd */
2473                 skb_queue_tail(&ppp->file.rq, skb);
2474                 /* limit queue length by dropping old frames */
2475                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2476                        (skb = skb_dequeue(&ppp->file.rq)))
2477                         kfree_skb(skb);
2478                 /* wake up any process polling or blocking on read */
2479                 wake_up_interruptible(&ppp->file.rwait);
2480
2481         } else {
2482                 /* network protocol frame - give it to the kernel */
2483
2484 #ifdef CONFIG_PPP_FILTER
2485                 /* check if the packet passes the pass and active filters */
2486                 /* the filter instructions are constructed assuming
2487                    a four-byte PPP header on each packet */
2488                 if (ppp->pass_filter || ppp->active_filter) {
2489                         if (skb_unclone(skb, GFP_ATOMIC))
2490                                 goto err;
2491
2492                         *(u8 *)skb_push(skb, 2) = 0;
2493                         if (ppp->pass_filter &&
2494                             bpf_prog_run(ppp->pass_filter, skb) == 0) {
2495                                 if (ppp->debug & 1)
2496                                         netdev_printk(KERN_DEBUG, ppp->dev,
2497                                                       "PPP: inbound frame "
2498                                                       "not passed\n");
2499                                 kfree_skb(skb);
2500                                 return;
2501                         }
2502                         if (!(ppp->active_filter &&
2503                               bpf_prog_run(ppp->active_filter, skb) == 0))
2504                                 ppp->last_recv = jiffies;
2505                         __skb_pull(skb, 2);
2506                 } else
2507 #endif /* CONFIG_PPP_FILTER */
2508                         ppp->last_recv = jiffies;
2509
2510                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2511                     ppp->npmode[npi] != NPMODE_PASS) {
2512                         kfree_skb(skb);
2513                 } else {
2514                         /* chop off protocol */
2515                         skb_pull_rcsum(skb, 2);
2516                         skb->dev = ppp->dev;
2517                         skb->protocol = htons(npindex_to_ethertype[npi]);
2518                         skb_reset_mac_header(skb);
2519                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2520                                                       dev_net(ppp->dev)));
2521                         netif_rx(skb);
2522                 }
2523         }
2524         return;
2525
2526  err:
2527         kfree_skb(skb);
2528         ppp_receive_error(ppp);
2529 }
2530
2531 static struct sk_buff *
2532 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2533 {
2534         int proto = PPP_PROTO(skb);
2535         struct sk_buff *ns;
2536         int len;
2537
2538         /* Until we fix all the decompressor's need to make sure
2539          * data portion is linear.
2540          */
2541         if (!pskb_may_pull(skb, skb->len))
2542                 goto err;
2543
2544         if (proto == PPP_COMP) {
2545                 int obuff_size;
2546
2547                 switch(ppp->rcomp->compress_proto) {
2548                 case CI_MPPE:
2549                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2550                         break;
2551                 default:
2552                         obuff_size = ppp->mru + PPP_HDRLEN;
2553                         break;
2554                 }
2555
2556                 ns = dev_alloc_skb(obuff_size);
2557                 if (!ns) {
2558                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2559                                    "no memory\n");
2560                         goto err;
2561                 }
2562                 /* the decompressor still expects the A/C bytes in the hdr */
2563                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2564                                 skb->len + 2, ns->data, obuff_size);
2565                 if (len < 0) {
2566                         /* Pass the compressed frame to pppd as an
2567                            error indication. */
2568                         if (len == DECOMP_FATALERROR)
2569                                 ppp->rstate |= SC_DC_FERROR;
2570                         kfree_skb(ns);
2571                         goto err;
2572                 }
2573
2574                 consume_skb(skb);
2575                 skb = ns;
2576                 skb_put(skb, len);
2577                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2578
2579                 /* Don't call __ppp_decompress_proto() here, but instead rely on
2580                  * corresponding algo (mppe/bsd/deflate) to decompress it.
2581                  */
2582         } else {
2583                 /* Uncompressed frame - pass to decompressor so it
2584                    can update its dictionary if necessary. */
2585                 if (ppp->rcomp->incomp)
2586                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2587                                            skb->len + 2);
2588         }
2589
2590         return skb;
2591
2592  err:
2593         ppp->rstate |= SC_DC_ERROR;
2594         ppp_receive_error(ppp);
2595         return skb;
2596 }
2597
2598 #ifdef CONFIG_PPP_MULTILINK
2599 /*
2600  * Receive a multilink frame.
2601  * We put it on the reconstruction queue and then pull off
2602  * as many completed frames as we can.
2603  */
2604 static void
2605 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2606 {
2607         u32 mask, seq;
2608         struct channel *ch;
2609         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2610
2611         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2612                 goto err;               /* no good, throw it away */
2613
2614         /* Decode sequence number and begin/end bits */
2615         if (ppp->flags & SC_MP_SHORTSEQ) {
2616                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2617                 mask = 0xfff;
2618         } else {
2619                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2620                 mask = 0xffffff;
2621         }
2622         PPP_MP_CB(skb)->BEbits = skb->data[2];
2623         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2624
2625         /*
2626          * Do protocol ID decompression on the first fragment of each packet.
2627          * We have to do that here, because ppp_receive_nonmp_frame() expects
2628          * decompressed protocol field.
2629          */
2630         if (PPP_MP_CB(skb)->BEbits & B)
2631                 __ppp_decompress_proto(skb);
2632
2633         /*
2634          * Expand sequence number to 32 bits, making it as close
2635          * as possible to ppp->minseq.
2636          */
2637         seq |= ppp->minseq & ~mask;
2638         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2639                 seq += mask + 1;
2640         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2641                 seq -= mask + 1;        /* should never happen */
2642         PPP_MP_CB(skb)->sequence = seq;
2643         pch->lastseq = seq;
2644
2645         /*
2646          * If this packet comes before the next one we were expecting,
2647          * drop it.
2648          */
2649         if (seq_before(seq, ppp->nextseq)) {
2650                 kfree_skb(skb);
2651                 ++ppp->dev->stats.rx_dropped;
2652                 ppp_receive_error(ppp);
2653                 return;
2654         }
2655
2656         /*
2657          * Reevaluate minseq, the minimum over all channels of the
2658          * last sequence number received on each channel.  Because of
2659          * the increasing sequence number rule, we know that any fragment
2660          * before `minseq' which hasn't arrived is never going to arrive.
2661          * The list of channels can't change because we have the receive
2662          * side of the ppp unit locked.
2663          */
2664         list_for_each_entry(ch, &ppp->channels, clist) {
2665                 if (seq_before(ch->lastseq, seq))
2666                         seq = ch->lastseq;
2667         }
2668         if (seq_before(ppp->minseq, seq))
2669                 ppp->minseq = seq;
2670
2671         /* Put the fragment on the reconstruction queue */
2672         ppp_mp_insert(ppp, skb);
2673
2674         /* If the queue is getting long, don't wait any longer for packets
2675            before the start of the queue. */
2676         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2677                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2678                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2679                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2680         }
2681
2682         /* Pull completed packets off the queue and receive them. */
2683         while ((skb = ppp_mp_reconstruct(ppp))) {
2684                 if (pskb_may_pull(skb, 2))
2685                         ppp_receive_nonmp_frame(ppp, skb);
2686                 else {
2687                         ++ppp->dev->stats.rx_length_errors;
2688                         kfree_skb(skb);
2689                         ppp_receive_error(ppp);
2690                 }
2691         }
2692
2693         return;
2694
2695  err:
2696         kfree_skb(skb);
2697         ppp_receive_error(ppp);
2698 }
2699
2700 /*
2701  * Insert a fragment on the MP reconstruction queue.
2702  * The queue is ordered by increasing sequence number.
2703  */
2704 static void
2705 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2706 {
2707         struct sk_buff *p;
2708         struct sk_buff_head *list = &ppp->mrq;
2709         u32 seq = PPP_MP_CB(skb)->sequence;
2710
2711         /* N.B. we don't need to lock the list lock because we have the
2712            ppp unit receive-side lock. */
2713         skb_queue_walk(list, p) {
2714                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2715                         break;
2716         }
2717         __skb_queue_before(list, p, skb);
2718 }
2719
2720 /*
2721  * Reconstruct a packet from the MP fragment queue.
2722  * We go through increasing sequence numbers until we find a
2723  * complete packet, or we get to the sequence number for a fragment
2724  * which hasn't arrived but might still do so.
2725  */
2726 static struct sk_buff *
2727 ppp_mp_reconstruct(struct ppp *ppp)
2728 {
2729         u32 seq = ppp->nextseq;
2730         u32 minseq = ppp->minseq;
2731         struct sk_buff_head *list = &ppp->mrq;
2732         struct sk_buff *p, *tmp;
2733         struct sk_buff *head, *tail;
2734         struct sk_buff *skb = NULL;
2735         int lost = 0, len = 0;
2736
2737         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2738                 return NULL;
2739         head = __skb_peek(list);
2740         tail = NULL;
2741         skb_queue_walk_safe(list, p, tmp) {
2742         again:
2743                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2744                         /* this can't happen, anyway ignore the skb */
2745                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2746                                    "seq %u < %u\n",
2747                                    PPP_MP_CB(p)->sequence, seq);
2748                         __skb_unlink(p, list);
2749                         kfree_skb(p);
2750                         continue;
2751                 }
2752                 if (PPP_MP_CB(p)->sequence != seq) {
2753                         u32 oldseq;
2754                         /* Fragment `seq' is missing.  If it is after
2755                            minseq, it might arrive later, so stop here. */
2756                         if (seq_after(seq, minseq))
2757                                 break;
2758                         /* Fragment `seq' is lost, keep going. */
2759                         lost = 1;
2760                         oldseq = seq;
2761                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2762                                 minseq + 1: PPP_MP_CB(p)->sequence;
2763
2764                         if (ppp->debug & 1)
2765                                 netdev_printk(KERN_DEBUG, ppp->dev,
2766                                               "lost frag %u..%u\n",
2767                                               oldseq, seq-1);
2768
2769                         goto again;
2770                 }
2771
2772                 /*
2773                  * At this point we know that all the fragments from
2774                  * ppp->nextseq to seq are either present or lost.
2775                  * Also, there are no complete packets in the queue
2776                  * that have no missing fragments and end before this
2777                  * fragment.
2778                  */
2779
2780                 /* B bit set indicates this fragment starts a packet */
2781                 if (PPP_MP_CB(p)->BEbits & B) {
2782                         head = p;
2783                         lost = 0;
2784                         len = 0;
2785                 }
2786
2787                 len += p->len;
2788
2789                 /* Got a complete packet yet? */
2790                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2791                     (PPP_MP_CB(head)->BEbits & B)) {
2792                         if (len > ppp->mrru + 2) {
2793                                 ++ppp->dev->stats.rx_length_errors;
2794                                 netdev_printk(KERN_DEBUG, ppp->dev,
2795                                               "PPP: reconstructed packet"
2796                                               " is too long (%d)\n", len);
2797                         } else {
2798                                 tail = p;
2799                                 break;
2800                         }
2801                         ppp->nextseq = seq + 1;
2802                 }
2803
2804                 /*
2805                  * If this is the ending fragment of a packet,
2806                  * and we haven't found a complete valid packet yet,
2807                  * we can discard up to and including this fragment.
2808                  */
2809                 if (PPP_MP_CB(p)->BEbits & E) {
2810                         struct sk_buff *tmp2;
2811
2812                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2813                                 if (ppp->debug & 1)
2814                                         netdev_printk(KERN_DEBUG, ppp->dev,
2815                                                       "discarding frag %u\n",
2816                                                       PPP_MP_CB(p)->sequence);
2817                                 __skb_unlink(p, list);
2818                                 kfree_skb(p);
2819                         }
2820                         head = skb_peek(list);
2821                         if (!head)
2822                                 break;
2823                 }
2824                 ++seq;
2825         }
2826
2827         /* If we have a complete packet, copy it all into one skb. */
2828         if (tail != NULL) {
2829                 /* If we have discarded any fragments,
2830                    signal a receive error. */
2831                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2832                         skb_queue_walk_safe(list, p, tmp) {
2833                                 if (p == head)
2834                                         break;
2835                                 if (ppp->debug & 1)
2836                                         netdev_printk(KERN_DEBUG, ppp->dev,
2837                                                       "discarding frag %u\n",
2838                                                       PPP_MP_CB(p)->sequence);
2839                                 __skb_unlink(p, list);
2840                                 kfree_skb(p);
2841                         }
2842
2843                         if (ppp->debug & 1)
2844                                 netdev_printk(KERN_DEBUG, ppp->dev,
2845                                               "  missed pkts %u..%u\n",
2846                                               ppp->nextseq,
2847                                               PPP_MP_CB(head)->sequence-1);
2848                         ++ppp->dev->stats.rx_dropped;
2849                         ppp_receive_error(ppp);
2850                 }
2851
2852                 skb = head;
2853                 if (head != tail) {
2854                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2855                         p = skb_queue_next(list, head);
2856                         __skb_unlink(skb, list);
2857                         skb_queue_walk_from_safe(list, p, tmp) {
2858                                 __skb_unlink(p, list);
2859                                 *fragpp = p;
2860                                 p->next = NULL;
2861                                 fragpp = &p->next;
2862
2863                                 skb->len += p->len;
2864                                 skb->data_len += p->len;
2865                                 skb->truesize += p->truesize;
2866
2867                                 if (p == tail)
2868                                         break;
2869                         }
2870                 } else {
2871                         __skb_unlink(skb, list);
2872                 }
2873
2874                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2875         }
2876
2877         return skb;
2878 }
2879 #endif /* CONFIG_PPP_MULTILINK */
2880
2881 /*
2882  * Channel interface.
2883  */
2884
2885 /* Create a new, unattached ppp channel. */
2886 int ppp_register_channel(struct ppp_channel *chan)
2887 {
2888         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2889 }
2890
2891 /* Create a new, unattached ppp channel for specified net. */
2892 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2893 {
2894         struct channel *pch;
2895         struct ppp_net *pn;
2896
2897         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2898         if (!pch)
2899                 return -ENOMEM;
2900
2901         pn = ppp_pernet(net);
2902
2903         pch->ppp = NULL;
2904         pch->chan = chan;
2905         pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
2906         chan->ppp = pch;
2907         init_ppp_file(&pch->file, CHANNEL);
2908         pch->file.hdrlen = chan->hdrlen;
2909 #ifdef CONFIG_PPP_MULTILINK
2910         pch->lastseq = -1;
2911 #endif /* CONFIG_PPP_MULTILINK */
2912         init_rwsem(&pch->chan_sem);
2913         spin_lock_init(&pch->downl);
2914         rwlock_init(&pch->upl);
2915
2916         spin_lock_bh(&pn->all_channels_lock);
2917         pch->file.index = ++pn->last_channel_index;
2918         list_add(&pch->list, &pn->new_channels);
2919         atomic_inc(&channel_count);
2920         spin_unlock_bh(&pn->all_channels_lock);
2921
2922         return 0;
2923 }
2924
2925 /*
2926  * Return the index of a channel.
2927  */
2928 int ppp_channel_index(struct ppp_channel *chan)
2929 {
2930         struct channel *pch = chan->ppp;
2931
2932         if (pch)
2933                 return pch->file.index;
2934         return -1;
2935 }
2936
2937 /*
2938  * Return the PPP unit number to which a channel is connected.
2939  */
2940 int ppp_unit_number(struct ppp_channel *chan)
2941 {
2942         struct channel *pch = chan->ppp;
2943         int unit = -1;
2944
2945         if (pch) {
2946                 read_lock_bh(&pch->upl);
2947                 if (pch->ppp)
2948                         unit = pch->ppp->file.index;
2949                 read_unlock_bh(&pch->upl);
2950         }
2951         return unit;
2952 }
2953
2954 /*
2955  * Return the PPP device interface name of a channel.
2956  */
2957 char *ppp_dev_name(struct ppp_channel *chan)
2958 {
2959         struct channel *pch = chan->ppp;
2960         char *name = NULL;
2961
2962         if (pch) {
2963                 read_lock_bh(&pch->upl);
2964                 if (pch->ppp && pch->ppp->dev)
2965                         name = pch->ppp->dev->name;
2966                 read_unlock_bh(&pch->upl);
2967         }
2968         return name;
2969 }
2970
2971
2972 /*
2973  * Disconnect a channel from the generic layer.
2974  * This must be called in process context.
2975  */
2976 void
2977 ppp_unregister_channel(struct ppp_channel *chan)
2978 {
2979         struct channel *pch = chan->ppp;
2980         struct ppp_net *pn;
2981
2982         if (!pch)
2983                 return;         /* should never happen */
2984
2985         chan->ppp = NULL;
2986
2987         /*
2988          * This ensures that we have returned from any calls into
2989          * the channel's start_xmit or ioctl routine before we proceed.
2990          */
2991         down_write(&pch->chan_sem);
2992         spin_lock_bh(&pch->downl);
2993         pch->chan = NULL;
2994         spin_unlock_bh(&pch->downl);
2995         up_write(&pch->chan_sem);
2996         ppp_disconnect_channel(pch);
2997
2998         pn = ppp_pernet(pch->chan_net);
2999         spin_lock_bh(&pn->all_channels_lock);
3000         list_del(&pch->list);
3001         spin_unlock_bh(&pn->all_channels_lock);
3002
3003         ppp_unbridge_channels(pch);
3004
3005         pch->file.dead = 1;
3006         wake_up_interruptible(&pch->file.rwait);
3007
3008         if (refcount_dec_and_test(&pch->file.refcnt))
3009                 ppp_destroy_channel(pch);
3010 }
3011
3012 /*
3013  * Callback from a channel when it can accept more to transmit.
3014  * This should be called at BH/softirq level, not interrupt level.
3015  */
3016 void
3017 ppp_output_wakeup(struct ppp_channel *chan)
3018 {
3019         struct channel *pch = chan->ppp;
3020
3021         if (!pch)
3022                 return;
3023         ppp_channel_push(pch);
3024 }
3025
3026 /*
3027  * Compression control.
3028  */
3029
3030 /* Process the PPPIOCSCOMPRESS ioctl. */
3031 static int
3032 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3033 {
3034         int err = -EFAULT;
3035         struct compressor *cp, *ocomp;
3036         void *state, *ostate;
3037         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3038
3039         if (data->length > CCP_MAX_OPTION_LENGTH)
3040                 goto out;
3041         if (copy_from_user(ccp_option, data->ptr, data->length))
3042                 goto out;
3043
3044         err = -EINVAL;
3045         if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3046                 goto out;
3047
3048         cp = try_then_request_module(
3049                 find_compressor(ccp_option[0]),
3050                 "ppp-compress-%d", ccp_option[0]);
3051         if (!cp)
3052                 goto out;
3053
3054         err = -ENOBUFS;
3055         if (data->transmit) {
3056                 state = cp->comp_alloc(ccp_option, data->length);
3057                 if (state) {
3058                         ppp_xmit_lock(ppp);
3059                         ppp->xstate &= ~SC_COMP_RUN;
3060                         ocomp = ppp->xcomp;
3061                         ostate = ppp->xc_state;
3062                         ppp->xcomp = cp;
3063                         ppp->xc_state = state;
3064                         ppp_xmit_unlock(ppp);
3065                         if (ostate) {
3066                                 ocomp->comp_free(ostate);
3067                                 module_put(ocomp->owner);
3068                         }
3069                         err = 0;
3070                 } else
3071                         module_put(cp->owner);
3072
3073         } else {
3074                 state = cp->decomp_alloc(ccp_option, data->length);
3075                 if (state) {
3076                         ppp_recv_lock(ppp);
3077                         ppp->rstate &= ~SC_DECOMP_RUN;
3078                         ocomp = ppp->rcomp;
3079                         ostate = ppp->rc_state;
3080                         ppp->rcomp = cp;
3081                         ppp->rc_state = state;
3082                         ppp_recv_unlock(ppp);
3083                         if (ostate) {
3084                                 ocomp->decomp_free(ostate);
3085                                 module_put(ocomp->owner);
3086                         }
3087                         err = 0;
3088                 } else
3089                         module_put(cp->owner);
3090         }
3091
3092  out:
3093         return err;
3094 }
3095
3096 /*
3097  * Look at a CCP packet and update our state accordingly.
3098  * We assume the caller has the xmit or recv path locked.
3099  */
3100 static void
3101 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3102 {
3103         unsigned char *dp;
3104         int len;
3105
3106         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3107                 return; /* no header */
3108         dp = skb->data + 2;
3109
3110         switch (CCP_CODE(dp)) {
3111         case CCP_CONFREQ:
3112
3113                 /* A ConfReq starts negotiation of compression
3114                  * in one direction of transmission,
3115                  * and hence brings it down...but which way?
3116                  *
3117                  * Remember:
3118                  * A ConfReq indicates what the sender would like to receive
3119                  */
3120                 if(inbound)
3121                         /* He is proposing what I should send */
3122                         ppp->xstate &= ~SC_COMP_RUN;
3123                 else
3124                         /* I am proposing to what he should send */
3125                         ppp->rstate &= ~SC_DECOMP_RUN;
3126
3127                 break;
3128
3129         case CCP_TERMREQ:
3130         case CCP_TERMACK:
3131                 /*
3132                  * CCP is going down, both directions of transmission
3133                  */
3134                 ppp->rstate &= ~SC_DECOMP_RUN;
3135                 ppp->xstate &= ~SC_COMP_RUN;
3136                 break;
3137
3138         case CCP_CONFACK:
3139                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3140                         break;
3141                 len = CCP_LENGTH(dp);
3142                 if (!pskb_may_pull(skb, len + 2))
3143                         return;         /* too short */
3144                 dp += CCP_HDRLEN;
3145                 len -= CCP_HDRLEN;
3146                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3147                         break;
3148                 if (inbound) {
3149                         /* we will start receiving compressed packets */
3150                         if (!ppp->rc_state)
3151                                 break;
3152                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3153                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
3154                                 ppp->rstate |= SC_DECOMP_RUN;
3155                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3156                         }
3157                 } else {
3158                         /* we will soon start sending compressed packets */
3159                         if (!ppp->xc_state)
3160                                 break;
3161                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3162                                         ppp->file.index, 0, ppp->debug))
3163                                 ppp->xstate |= SC_COMP_RUN;
3164                 }
3165                 break;
3166
3167         case CCP_RESETACK:
3168                 /* reset the [de]compressor */
3169                 if ((ppp->flags & SC_CCP_UP) == 0)
3170                         break;
3171                 if (inbound) {
3172                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3173                                 ppp->rcomp->decomp_reset(ppp->rc_state);
3174                                 ppp->rstate &= ~SC_DC_ERROR;
3175                         }
3176                 } else {
3177                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3178                                 ppp->xcomp->comp_reset(ppp->xc_state);
3179                 }
3180                 break;
3181         }
3182 }
3183
3184 /* Free up compression resources. */
3185 static void
3186 ppp_ccp_closed(struct ppp *ppp)
3187 {
3188         void *xstate, *rstate;
3189         struct compressor *xcomp, *rcomp;
3190
3191         ppp_lock(ppp);
3192         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3193         ppp->xstate = 0;
3194         xcomp = ppp->xcomp;
3195         xstate = ppp->xc_state;
3196         ppp->xc_state = NULL;
3197         ppp->rstate = 0;
3198         rcomp = ppp->rcomp;
3199         rstate = ppp->rc_state;
3200         ppp->rc_state = NULL;
3201         ppp_unlock(ppp);
3202
3203         if (xstate) {
3204                 xcomp->comp_free(xstate);
3205                 module_put(xcomp->owner);
3206         }
3207         if (rstate) {
3208                 rcomp->decomp_free(rstate);
3209                 module_put(rcomp->owner);
3210         }
3211 }
3212
3213 /* List of compressors. */
3214 static LIST_HEAD(compressor_list);
3215 static DEFINE_SPINLOCK(compressor_list_lock);
3216
3217 struct compressor_entry {
3218         struct list_head list;
3219         struct compressor *comp;
3220 };
3221
3222 static struct compressor_entry *
3223 find_comp_entry(int proto)
3224 {
3225         struct compressor_entry *ce;
3226
3227         list_for_each_entry(ce, &compressor_list, list) {
3228                 if (ce->comp->compress_proto == proto)
3229                         return ce;
3230         }
3231         return NULL;
3232 }
3233
3234 /* Register a compressor */
3235 int
3236 ppp_register_compressor(struct compressor *cp)
3237 {
3238         struct compressor_entry *ce;
3239         int ret;
3240         spin_lock(&compressor_list_lock);
3241         ret = -EEXIST;
3242         if (find_comp_entry(cp->compress_proto))
3243                 goto out;
3244         ret = -ENOMEM;
3245         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3246         if (!ce)
3247                 goto out;
3248         ret = 0;
3249         ce->comp = cp;
3250         list_add(&ce->list, &compressor_list);
3251  out:
3252         spin_unlock(&compressor_list_lock);
3253         return ret;
3254 }
3255
3256 /* Unregister a compressor */
3257 void
3258 ppp_unregister_compressor(struct compressor *cp)
3259 {
3260         struct compressor_entry *ce;
3261
3262         spin_lock(&compressor_list_lock);
3263         ce = find_comp_entry(cp->compress_proto);
3264         if (ce && ce->comp == cp) {
3265                 list_del(&ce->list);
3266                 kfree(ce);
3267         }
3268         spin_unlock(&compressor_list_lock);
3269 }
3270
3271 /* Find a compressor. */
3272 static struct compressor *
3273 find_compressor(int type)
3274 {
3275         struct compressor_entry *ce;
3276         struct compressor *cp = NULL;
3277
3278         spin_lock(&compressor_list_lock);
3279         ce = find_comp_entry(type);
3280         if (ce) {
3281                 cp = ce->comp;
3282                 if (!try_module_get(cp->owner))
3283                         cp = NULL;
3284         }
3285         spin_unlock(&compressor_list_lock);
3286         return cp;
3287 }
3288
3289 /*
3290  * Miscelleneous stuff.
3291  */
3292
3293 static void
3294 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3295 {
3296         struct slcompress *vj = ppp->vj;
3297
3298         memset(st, 0, sizeof(*st));
3299         st->p.ppp_ipackets = ppp->stats64.rx_packets;
3300         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3301         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3302         st->p.ppp_opackets = ppp->stats64.tx_packets;
3303         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3304         st->p.ppp_obytes = ppp->stats64.tx_bytes;
3305         if (!vj)
3306                 return;
3307         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3308         st->vj.vjs_compressed = vj->sls_o_compressed;
3309         st->vj.vjs_searches = vj->sls_o_searches;
3310         st->vj.vjs_misses = vj->sls_o_misses;
3311         st->vj.vjs_errorin = vj->sls_i_error;
3312         st->vj.vjs_tossed = vj->sls_i_tossed;
3313         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3314         st->vj.vjs_compressedin = vj->sls_i_compressed;
3315 }
3316
3317 /*
3318  * Stuff for handling the lists of ppp units and channels
3319  * and for initialization.
3320  */
3321
3322 /*
3323  * Create a new ppp interface unit.  Fails if it can't allocate memory
3324  * or if there is already a unit with the requested number.
3325  * unit == -1 means allocate a new number.
3326  */
3327 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3328 {
3329         struct ppp_config conf = {
3330                 .file = file,
3331                 .unit = *unit,
3332                 .ifname_is_set = false,
3333         };
3334         struct net_device *dev;
3335         struct ppp *ppp;
3336         int err;
3337
3338         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3339         if (!dev) {
3340                 err = -ENOMEM;
3341                 goto err;
3342         }
3343         dev_net_set(dev, net);
3344         dev->rtnl_link_ops = &ppp_link_ops;
3345
3346         rtnl_lock();
3347
3348         err = ppp_dev_configure(net, dev, &conf);
3349         if (err < 0)
3350                 goto err_dev;
3351         ppp = netdev_priv(dev);
3352         *unit = ppp->file.index;
3353
3354         rtnl_unlock();
3355
3356         return 0;
3357
3358 err_dev:
3359         rtnl_unlock();
3360         free_netdev(dev);
3361 err:
3362         return err;
3363 }
3364
3365 /*
3366  * Initialize a ppp_file structure.
3367  */
3368 static void
3369 init_ppp_file(struct ppp_file *pf, int kind)
3370 {
3371         pf->kind = kind;
3372         skb_queue_head_init(&pf->xq);
3373         skb_queue_head_init(&pf->rq);
3374         refcount_set(&pf->refcnt, 1);
3375         init_waitqueue_head(&pf->rwait);
3376 }
3377
3378 /*
3379  * Free the memory used by a ppp unit.  This is only called once
3380  * there are no channels connected to the unit and no file structs
3381  * that reference the unit.
3382  */
3383 static void ppp_destroy_interface(struct ppp *ppp)
3384 {
3385         atomic_dec(&ppp_unit_count);
3386
3387         if (!ppp->file.dead || ppp->n_channels) {
3388                 /* "can't happen" */
3389                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3390                            "but dead=%d n_channels=%d !\n",
3391                            ppp, ppp->file.dead, ppp->n_channels);
3392                 return;
3393         }
3394
3395         ppp_ccp_closed(ppp);
3396         if (ppp->vj) {
3397                 slhc_free(ppp->vj);
3398                 ppp->vj = NULL;
3399         }
3400         skb_queue_purge(&ppp->file.xq);
3401         skb_queue_purge(&ppp->file.rq);
3402 #ifdef CONFIG_PPP_MULTILINK
3403         skb_queue_purge(&ppp->mrq);
3404 #endif /* CONFIG_PPP_MULTILINK */
3405 #ifdef CONFIG_PPP_FILTER
3406         if (ppp->pass_filter) {
3407                 bpf_prog_destroy(ppp->pass_filter);
3408                 ppp->pass_filter = NULL;
3409         }
3410
3411         if (ppp->active_filter) {
3412                 bpf_prog_destroy(ppp->active_filter);
3413                 ppp->active_filter = NULL;
3414         }
3415 #endif /* CONFIG_PPP_FILTER */
3416
3417         kfree_skb(ppp->xmit_pending);
3418         free_percpu(ppp->xmit_recursion);
3419
3420         free_netdev(ppp->dev);
3421 }
3422
3423 /*
3424  * Locate an existing ppp unit.
3425  * The caller should have locked the all_ppp_mutex.
3426  */
3427 static struct ppp *
3428 ppp_find_unit(struct ppp_net *pn, int unit)
3429 {
3430         return unit_find(&pn->units_idr, unit);
3431 }
3432
3433 /*
3434  * Locate an existing ppp channel.
3435  * The caller should have locked the all_channels_lock.
3436  * First we look in the new_channels list, then in the
3437  * all_channels list.  If found in the new_channels list,
3438  * we move it to the all_channels list.  This is for speed
3439  * when we have a lot of channels in use.
3440  */
3441 static struct channel *
3442 ppp_find_channel(struct ppp_net *pn, int unit)
3443 {
3444         struct channel *pch;
3445
3446         list_for_each_entry(pch, &pn->new_channels, list) {
3447                 if (pch->file.index == unit) {
3448                         list_move(&pch->list, &pn->all_channels);
3449                         return pch;
3450                 }
3451         }
3452
3453         list_for_each_entry(pch, &pn->all_channels, list) {
3454                 if (pch->file.index == unit)
3455                         return pch;
3456         }
3457
3458         return NULL;
3459 }
3460
3461 /*
3462  * Connect a PPP channel to a PPP interface unit.
3463  */
3464 static int
3465 ppp_connect_channel(struct channel *pch, int unit)
3466 {
3467         struct ppp *ppp;
3468         struct ppp_net *pn;
3469         int ret = -ENXIO;
3470         int hdrlen;
3471
3472         pn = ppp_pernet(pch->chan_net);
3473
3474         mutex_lock(&pn->all_ppp_mutex);
3475         ppp = ppp_find_unit(pn, unit);
3476         if (!ppp)
3477                 goto out;
3478         write_lock_bh(&pch->upl);
3479         ret = -EINVAL;
3480         if (pch->ppp ||
3481             rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3482                 goto outl;
3483
3484         ppp_lock(ppp);
3485         spin_lock_bh(&pch->downl);
3486         if (!pch->chan) {
3487                 /* Don't connect unregistered channels */
3488                 spin_unlock_bh(&pch->downl);
3489                 ppp_unlock(ppp);
3490                 ret = -ENOTCONN;
3491                 goto outl;
3492         }
3493         spin_unlock_bh(&pch->downl);
3494         if (pch->file.hdrlen > ppp->file.hdrlen)
3495                 ppp->file.hdrlen = pch->file.hdrlen;
3496         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3497         if (hdrlen > ppp->dev->hard_header_len)
3498                 ppp->dev->hard_header_len = hdrlen;
3499         list_add_tail(&pch->clist, &ppp->channels);
3500         ++ppp->n_channels;
3501         pch->ppp = ppp;
3502         refcount_inc(&ppp->file.refcnt);
3503         ppp_unlock(ppp);
3504         ret = 0;
3505
3506  outl:
3507         write_unlock_bh(&pch->upl);
3508  out:
3509         mutex_unlock(&pn->all_ppp_mutex);
3510         return ret;
3511 }
3512
3513 /*
3514  * Disconnect a channel from its ppp unit.
3515  */
3516 static int
3517 ppp_disconnect_channel(struct channel *pch)
3518 {
3519         struct ppp *ppp;
3520         int err = -EINVAL;
3521
3522         write_lock_bh(&pch->upl);
3523         ppp = pch->ppp;
3524         pch->ppp = NULL;
3525         write_unlock_bh(&pch->upl);
3526         if (ppp) {
3527                 /* remove it from the ppp unit's list */
3528                 ppp_lock(ppp);
3529                 list_del(&pch->clist);
3530                 if (--ppp->n_channels == 0)
3531                         wake_up_interruptible(&ppp->file.rwait);
3532                 ppp_unlock(ppp);
3533                 if (refcount_dec_and_test(&ppp->file.refcnt))
3534                         ppp_destroy_interface(ppp);
3535                 err = 0;
3536         }
3537         return err;
3538 }
3539
3540 /*
3541  * Free up the resources used by a ppp channel.
3542  */
3543 static void ppp_destroy_channel(struct channel *pch)
3544 {
3545         put_net_track(pch->chan_net, &pch->ns_tracker);
3546         pch->chan_net = NULL;
3547
3548         atomic_dec(&channel_count);
3549
3550         if (!pch->file.dead) {
3551                 /* "can't happen" */
3552                 pr_err("ppp: destroying undead channel %p !\n", pch);
3553                 return;
3554         }
3555         skb_queue_purge(&pch->file.xq);
3556         skb_queue_purge(&pch->file.rq);
3557         kfree(pch);
3558 }
3559
3560 static void __exit ppp_cleanup(void)
3561 {
3562         /* should never happen */
3563         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3564                 pr_err("PPP: removing module but units remain!\n");
3565         rtnl_link_unregister(&ppp_link_ops);
3566         unregister_chrdev(PPP_MAJOR, "ppp");
3567         device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0));
3568         class_unregister(&ppp_class);
3569         unregister_pernet_device(&ppp_net_ops);
3570 }
3571
3572 /*
3573  * Units handling. Caller must protect concurrent access
3574  * by holding all_ppp_mutex
3575  */
3576
3577 /* associate pointer with specified number */
3578 static int unit_set(struct idr *p, void *ptr, int n)
3579 {
3580         int unit;
3581
3582         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3583         if (unit == -ENOSPC)
3584                 unit = -EINVAL;
3585         return unit;
3586 }
3587
3588 /* get new free unit number and associate pointer with it */
3589 static int unit_get(struct idr *p, void *ptr, int min)
3590 {
3591         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3592 }
3593
3594 /* put unit number back to a pool */
3595 static void unit_put(struct idr *p, int n)
3596 {
3597         idr_remove(p, n);
3598 }
3599
3600 /* get pointer associated with the number */
3601 static void *unit_find(struct idr *p, int n)
3602 {
3603         return idr_find(p, n);
3604 }
3605
3606 /* Module/initialization stuff */
3607
3608 module_init(ppp_init);
3609 module_exit(ppp_cleanup);
3610
3611 EXPORT_SYMBOL(ppp_register_net_channel);
3612 EXPORT_SYMBOL(ppp_register_channel);
3613 EXPORT_SYMBOL(ppp_unregister_channel);
3614 EXPORT_SYMBOL(ppp_channel_index);
3615 EXPORT_SYMBOL(ppp_unit_number);
3616 EXPORT_SYMBOL(ppp_dev_name);
3617 EXPORT_SYMBOL(ppp_input);
3618 EXPORT_SYMBOL(ppp_input_error);
3619 EXPORT_SYMBOL(ppp_output_wakeup);
3620 EXPORT_SYMBOL(ppp_register_compressor);
3621 EXPORT_SYMBOL(ppp_unregister_compressor);
3622 MODULE_DESCRIPTION("Generic PPP layer driver");
3623 MODULE_LICENSE("GPL");
3624 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3625 MODULE_ALIAS_RTNL_LINK("ppp");
3626 MODULE_ALIAS("devname:ppp");