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