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, ITER_DEST, &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_array_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("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         skb->dev = ppp->dev;
1747
1748         if (proto < 0x8000) {
1749 #ifdef CONFIG_PPP_FILTER
1750                 /* check if we should pass this packet */
1751                 /* the filter instructions are constructed assuming
1752                    a four-byte PPP header on each packet */
1753                 *(u8 *)skb_push(skb, 2) = 1;
1754                 if (ppp->pass_filter &&
1755                     bpf_prog_run(ppp->pass_filter, skb) == 0) {
1756                         if (ppp->debug & 1)
1757                                 netdev_printk(KERN_DEBUG, ppp->dev,
1758                                               "PPP: outbound frame "
1759                                               "not passed\n");
1760                         kfree_skb(skb);
1761                         return;
1762                 }
1763                 /* if this packet passes the active filter, record the time */
1764                 if (!(ppp->active_filter &&
1765                       bpf_prog_run(ppp->active_filter, skb) == 0))
1766                         ppp->last_xmit = jiffies;
1767                 skb_pull(skb, 2);
1768 #else
1769                 /* for data packets, record the time */
1770                 ppp->last_xmit = jiffies;
1771 #endif /* CONFIG_PPP_FILTER */
1772         }
1773
1774         ++ppp->stats64.tx_packets;
1775         ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1776
1777         switch (proto) {
1778         case PPP_IP:
1779                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1780                         break;
1781                 /* try to do VJ TCP header compression */
1782                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1783                                     GFP_ATOMIC);
1784                 if (!new_skb) {
1785                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1786                         goto drop;
1787                 }
1788                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1789                 cp = skb->data + 2;
1790                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1791                                     new_skb->data + 2, &cp,
1792                                     !(ppp->flags & SC_NO_TCP_CCID));
1793                 if (cp == skb->data + 2) {
1794                         /* didn't compress */
1795                         consume_skb(new_skb);
1796                 } else {
1797                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1798                                 proto = PPP_VJC_COMP;
1799                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1800                         } else {
1801                                 proto = PPP_VJC_UNCOMP;
1802                                 cp[0] = skb->data[2];
1803                         }
1804                         consume_skb(skb);
1805                         skb = new_skb;
1806                         cp = skb_put(skb, len + 2);
1807                         cp[0] = 0;
1808                         cp[1] = proto;
1809                 }
1810                 break;
1811
1812         case PPP_CCP:
1813                 /* peek at outbound CCP frames */
1814                 ppp_ccp_peek(ppp, skb, 0);
1815                 break;
1816         }
1817
1818         /* try to do packet compression */
1819         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1820             proto != PPP_LCP && proto != PPP_CCP) {
1821                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1822                         if (net_ratelimit())
1823                                 netdev_err(ppp->dev,
1824                                            "ppp: compression required but "
1825                                            "down - pkt dropped.\n");
1826                         goto drop;
1827                 }
1828                 skb = pad_compress_skb(ppp, skb);
1829                 if (!skb)
1830                         goto drop;
1831         }
1832
1833         /*
1834          * If we are waiting for traffic (demand dialling),
1835          * queue it up for pppd to receive.
1836          */
1837         if (ppp->flags & SC_LOOP_TRAFFIC) {
1838                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1839                         goto drop;
1840                 skb_queue_tail(&ppp->file.rq, skb);
1841                 wake_up_interruptible(&ppp->file.rwait);
1842                 return;
1843         }
1844
1845         ppp->xmit_pending = skb;
1846         ppp_push(ppp);
1847         return;
1848
1849  drop:
1850         kfree_skb(skb);
1851         ++ppp->dev->stats.tx_errors;
1852 }
1853
1854 /*
1855  * Try to send the frame in xmit_pending.
1856  * The caller should have the xmit path locked.
1857  */
1858 static void
1859 ppp_push(struct ppp *ppp)
1860 {
1861         struct list_head *list;
1862         struct channel *pch;
1863         struct sk_buff *skb = ppp->xmit_pending;
1864
1865         if (!skb)
1866                 return;
1867
1868         list = &ppp->channels;
1869         if (list_empty(list)) {
1870                 /* nowhere to send the packet, just drop it */
1871                 ppp->xmit_pending = NULL;
1872                 kfree_skb(skb);
1873                 return;
1874         }
1875
1876         if ((ppp->flags & SC_MULTILINK) == 0) {
1877                 /* not doing multilink: send it down the first channel */
1878                 list = list->next;
1879                 pch = list_entry(list, struct channel, clist);
1880
1881                 spin_lock(&pch->downl);
1882                 if (pch->chan) {
1883                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1884                                 ppp->xmit_pending = NULL;
1885                 } else {
1886                         /* channel got unregistered */
1887                         kfree_skb(skb);
1888                         ppp->xmit_pending = NULL;
1889                 }
1890                 spin_unlock(&pch->downl);
1891                 return;
1892         }
1893
1894 #ifdef CONFIG_PPP_MULTILINK
1895         /* Multilink: fragment the packet over as many links
1896            as can take the packet at the moment. */
1897         if (!ppp_mp_explode(ppp, skb))
1898                 return;
1899 #endif /* CONFIG_PPP_MULTILINK */
1900
1901         ppp->xmit_pending = NULL;
1902         kfree_skb(skb);
1903 }
1904
1905 #ifdef CONFIG_PPP_MULTILINK
1906 static bool mp_protocol_compress __read_mostly = true;
1907 module_param(mp_protocol_compress, bool, 0644);
1908 MODULE_PARM_DESC(mp_protocol_compress,
1909                  "compress protocol id in multilink fragments");
1910
1911 /*
1912  * Divide a packet to be transmitted into fragments and
1913  * send them out the individual links.
1914  */
1915 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1916 {
1917         int len, totlen;
1918         int i, bits, hdrlen, mtu;
1919         int flen;
1920         int navail, nfree, nzero;
1921         int nbigger;
1922         int totspeed;
1923         int totfree;
1924         unsigned char *p, *q;
1925         struct list_head *list;
1926         struct channel *pch;
1927         struct sk_buff *frag;
1928         struct ppp_channel *chan;
1929
1930         totspeed = 0; /*total bitrate of the bundle*/
1931         nfree = 0; /* # channels which have no packet already queued */
1932         navail = 0; /* total # of usable channels (not deregistered) */
1933         nzero = 0; /* number of channels with zero speed associated*/
1934         totfree = 0; /*total # of channels available and
1935                                   *having no queued packets before
1936                                   *starting the fragmentation*/
1937
1938         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1939         i = 0;
1940         list_for_each_entry(pch, &ppp->channels, clist) {
1941                 if (pch->chan) {
1942                         pch->avail = 1;
1943                         navail++;
1944                         pch->speed = pch->chan->speed;
1945                 } else {
1946                         pch->avail = 0;
1947                 }
1948                 if (pch->avail) {
1949                         if (skb_queue_empty(&pch->file.xq) ||
1950                                 !pch->had_frag) {
1951                                         if (pch->speed == 0)
1952                                                 nzero++;
1953                                         else
1954                                                 totspeed += pch->speed;
1955
1956                                         pch->avail = 2;
1957                                         ++nfree;
1958                                         ++totfree;
1959                                 }
1960                         if (!pch->had_frag && i < ppp->nxchan)
1961                                 ppp->nxchan = i;
1962                 }
1963                 ++i;
1964         }
1965         /*
1966          * Don't start sending this packet unless at least half of
1967          * the channels are free.  This gives much better TCP
1968          * performance if we have a lot of channels.
1969          */
1970         if (nfree == 0 || nfree < navail / 2)
1971                 return 0; /* can't take now, leave it in xmit_pending */
1972
1973         /* Do protocol field compression */
1974         p = skb->data;
1975         len = skb->len;
1976         if (*p == 0 && mp_protocol_compress) {
1977                 ++p;
1978                 --len;
1979         }
1980
1981         totlen = len;
1982         nbigger = len % nfree;
1983
1984         /* skip to the channel after the one we last used
1985            and start at that one */
1986         list = &ppp->channels;
1987         for (i = 0; i < ppp->nxchan; ++i) {
1988                 list = list->next;
1989                 if (list == &ppp->channels) {
1990                         i = 0;
1991                         break;
1992                 }
1993         }
1994
1995         /* create a fragment for each channel */
1996         bits = B;
1997         while (len > 0) {
1998                 list = list->next;
1999                 if (list == &ppp->channels) {
2000                         i = 0;
2001                         continue;
2002                 }
2003                 pch = list_entry(list, struct channel, clist);
2004                 ++i;
2005                 if (!pch->avail)
2006                         continue;
2007
2008                 /*
2009                  * Skip this channel if it has a fragment pending already and
2010                  * we haven't given a fragment to all of the free channels.
2011                  */
2012                 if (pch->avail == 1) {
2013                         if (nfree > 0)
2014                                 continue;
2015                 } else {
2016                         pch->avail = 1;
2017                 }
2018
2019                 /* check the channel's mtu and whether it is still attached. */
2020                 spin_lock(&pch->downl);
2021                 if (pch->chan == NULL) {
2022                         /* can't use this channel, it's being deregistered */
2023                         if (pch->speed == 0)
2024                                 nzero--;
2025                         else
2026                                 totspeed -= pch->speed;
2027
2028                         spin_unlock(&pch->downl);
2029                         pch->avail = 0;
2030                         totlen = len;
2031                         totfree--;
2032                         nfree--;
2033                         if (--navail == 0)
2034                                 break;
2035                         continue;
2036                 }
2037
2038                 /*
2039                 *if the channel speed is not set divide
2040                 *the packet evenly among the free channels;
2041                 *otherwise divide it according to the speed
2042                 *of the channel we are going to transmit on
2043                 */
2044                 flen = len;
2045                 if (nfree > 0) {
2046                         if (pch->speed == 0) {
2047                                 flen = len/nfree;
2048                                 if (nbigger > 0) {
2049                                         flen++;
2050                                         nbigger--;
2051                                 }
2052                         } else {
2053                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2054                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
2055                                 if (nbigger > 0) {
2056                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
2057                                         nbigger -= ((totfree - nzero)*pch->speed)/
2058                                                         totspeed;
2059                                 }
2060                         }
2061                         nfree--;
2062                 }
2063
2064                 /*
2065                  *check if we are on the last channel or
2066                  *we exceded the length of the data to
2067                  *fragment
2068                  */
2069                 if ((nfree <= 0) || (flen > len))
2070                         flen = len;
2071                 /*
2072                  *it is not worth to tx on slow channels:
2073                  *in that case from the resulting flen according to the
2074                  *above formula will be equal or less than zero.
2075                  *Skip the channel in this case
2076                  */
2077                 if (flen <= 0) {
2078                         pch->avail = 2;
2079                         spin_unlock(&pch->downl);
2080                         continue;
2081                 }
2082
2083                 /*
2084                  * hdrlen includes the 2-byte PPP protocol field, but the
2085                  * MTU counts only the payload excluding the protocol field.
2086                  * (RFC1661 Section 2)
2087                  */
2088                 mtu = pch->chan->mtu - (hdrlen - 2);
2089                 if (mtu < 4)
2090                         mtu = 4;
2091                 if (flen > mtu)
2092                         flen = mtu;
2093                 if (flen == len)
2094                         bits |= E;
2095                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2096                 if (!frag)
2097                         goto noskb;
2098                 q = skb_put(frag, flen + hdrlen);
2099
2100                 /* make the MP header */
2101                 put_unaligned_be16(PPP_MP, q);
2102                 if (ppp->flags & SC_MP_XSHORTSEQ) {
2103                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2104                         q[3] = ppp->nxseq;
2105                 } else {
2106                         q[2] = bits;
2107                         q[3] = ppp->nxseq >> 16;
2108                         q[4] = ppp->nxseq >> 8;
2109                         q[5] = ppp->nxseq;
2110                 }
2111
2112                 memcpy(q + hdrlen, p, flen);
2113
2114                 /* try to send it down the channel */
2115                 chan = pch->chan;
2116                 if (!skb_queue_empty(&pch->file.xq) ||
2117                         !chan->ops->start_xmit(chan, frag))
2118                         skb_queue_tail(&pch->file.xq, frag);
2119                 pch->had_frag = 1;
2120                 p += flen;
2121                 len -= flen;
2122                 ++ppp->nxseq;
2123                 bits = 0;
2124                 spin_unlock(&pch->downl);
2125         }
2126         ppp->nxchan = i;
2127
2128         return 1;
2129
2130  noskb:
2131         spin_unlock(&pch->downl);
2132         if (ppp->debug & 1)
2133                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2134         ++ppp->dev->stats.tx_errors;
2135         ++ppp->nxseq;
2136         return 1;       /* abandon the frame */
2137 }
2138 #endif /* CONFIG_PPP_MULTILINK */
2139
2140 /* Try to send data out on a channel */
2141 static void __ppp_channel_push(struct channel *pch)
2142 {
2143         struct sk_buff *skb;
2144         struct ppp *ppp;
2145
2146         spin_lock(&pch->downl);
2147         if (pch->chan) {
2148                 while (!skb_queue_empty(&pch->file.xq)) {
2149                         skb = skb_dequeue(&pch->file.xq);
2150                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2151                                 /* put the packet back and try again later */
2152                                 skb_queue_head(&pch->file.xq, skb);
2153                                 break;
2154                         }
2155                 }
2156         } else {
2157                 /* channel got deregistered */
2158                 skb_queue_purge(&pch->file.xq);
2159         }
2160         spin_unlock(&pch->downl);
2161         /* see if there is anything from the attached unit to be sent */
2162         if (skb_queue_empty(&pch->file.xq)) {
2163                 ppp = pch->ppp;
2164                 if (ppp)
2165                         __ppp_xmit_process(ppp, NULL);
2166         }
2167 }
2168
2169 static void ppp_channel_push(struct channel *pch)
2170 {
2171         read_lock_bh(&pch->upl);
2172         if (pch->ppp) {
2173                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2174                 __ppp_channel_push(pch);
2175                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2176         } else {
2177                 __ppp_channel_push(pch);
2178         }
2179         read_unlock_bh(&pch->upl);
2180 }
2181
2182 /*
2183  * Receive-side routines.
2184  */
2185
2186 struct ppp_mp_skb_parm {
2187         u32             sequence;
2188         u8              BEbits;
2189 };
2190 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
2191
2192 static inline void
2193 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2194 {
2195         ppp_recv_lock(ppp);
2196         if (!ppp->closing)
2197                 ppp_receive_frame(ppp, skb, pch);
2198         else
2199                 kfree_skb(skb);
2200         ppp_recv_unlock(ppp);
2201 }
2202
2203 /**
2204  * __ppp_decompress_proto - Decompress protocol field, slim version.
2205  * @skb: Socket buffer where protocol field should be decompressed. It must have
2206  *       at least 1 byte of head room and 1 byte of linear data. First byte of
2207  *       data must be a protocol field byte.
2208  *
2209  * Decompress protocol field in PPP header if it's compressed, e.g. when
2210  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2211  * length are done in this function.
2212  */
2213 static void __ppp_decompress_proto(struct sk_buff *skb)
2214 {
2215         if (skb->data[0] & 0x01)
2216                 *(u8 *)skb_push(skb, 1) = 0x00;
2217 }
2218
2219 /**
2220  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2221  * @skb: Socket buffer where protocol field should be decompressed. First byte
2222  *       of data must be a protocol field byte.
2223  *
2224  * Decompress protocol field in PPP header if it's compressed, e.g. when
2225  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2226  * sure that skb data room is sufficient for Protocol field, before and after
2227  * decompression.
2228  *
2229  * Return: true - decompressed successfully, false - not enough room in skb.
2230  */
2231 static bool ppp_decompress_proto(struct sk_buff *skb)
2232 {
2233         /* At least one byte should be present (if protocol is compressed) */
2234         if (!pskb_may_pull(skb, 1))
2235                 return false;
2236
2237         __ppp_decompress_proto(skb);
2238
2239         /* Protocol field should occupy 2 bytes when not compressed */
2240         return pskb_may_pull(skb, 2);
2241 }
2242
2243 /* Attempt to handle a frame via. a bridged channel, if one exists.
2244  * If the channel is bridged, the frame is consumed by the bridge.
2245  * If not, the caller must handle the frame by normal recv mechanisms.
2246  * Returns true if the frame is consumed, false otherwise.
2247  */
2248 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2249 {
2250         struct channel *pchb;
2251
2252         rcu_read_lock();
2253         pchb = rcu_dereference(pch->bridge);
2254         if (!pchb)
2255                 goto out_rcu;
2256
2257         spin_lock(&pchb->downl);
2258         if (!pchb->chan) {
2259                 /* channel got unregistered */
2260                 kfree_skb(skb);
2261                 goto outl;
2262         }
2263
2264         skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2265         if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2266                 kfree_skb(skb);
2267
2268 outl:
2269         spin_unlock(&pchb->downl);
2270 out_rcu:
2271         rcu_read_unlock();
2272
2273         /* If pchb is set then we've consumed the packet */
2274         return !!pchb;
2275 }
2276
2277 void
2278 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2279 {
2280         struct channel *pch = chan->ppp;
2281         int proto;
2282
2283         if (!pch) {
2284                 kfree_skb(skb);
2285                 return;
2286         }
2287
2288         /* If the channel is bridged, transmit via. bridge */
2289         if (ppp_channel_bridge_input(pch, skb))
2290                 return;
2291
2292         read_lock_bh(&pch->upl);
2293         if (!ppp_decompress_proto(skb)) {
2294                 kfree_skb(skb);
2295                 if (pch->ppp) {
2296                         ++pch->ppp->dev->stats.rx_length_errors;
2297                         ppp_receive_error(pch->ppp);
2298                 }
2299                 goto done;
2300         }
2301
2302         proto = PPP_PROTO(skb);
2303         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2304                 /* put it on the channel queue */
2305                 skb_queue_tail(&pch->file.rq, skb);
2306                 /* drop old frames if queue too long */
2307                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2308                        (skb = skb_dequeue(&pch->file.rq)))
2309                         kfree_skb(skb);
2310                 wake_up_interruptible(&pch->file.rwait);
2311         } else {
2312                 ppp_do_recv(pch->ppp, skb, pch);
2313         }
2314
2315 done:
2316         read_unlock_bh(&pch->upl);
2317 }
2318
2319 /* Put a 0-length skb in the receive queue as an error indication */
2320 void
2321 ppp_input_error(struct ppp_channel *chan, int code)
2322 {
2323         struct channel *pch = chan->ppp;
2324         struct sk_buff *skb;
2325
2326         if (!pch)
2327                 return;
2328
2329         read_lock_bh(&pch->upl);
2330         if (pch->ppp) {
2331                 skb = alloc_skb(0, GFP_ATOMIC);
2332                 if (skb) {
2333                         skb->len = 0;           /* probably unnecessary */
2334                         skb->cb[0] = code;
2335                         ppp_do_recv(pch->ppp, skb, pch);
2336                 }
2337         }
2338         read_unlock_bh(&pch->upl);
2339 }
2340
2341 /*
2342  * We come in here to process a received frame.
2343  * The receive side of the ppp unit is locked.
2344  */
2345 static void
2346 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2347 {
2348         /* note: a 0-length skb is used as an error indication */
2349         if (skb->len > 0) {
2350                 skb_checksum_complete_unset(skb);
2351 #ifdef CONFIG_PPP_MULTILINK
2352                 /* XXX do channel-level decompression here */
2353                 if (PPP_PROTO(skb) == PPP_MP)
2354                         ppp_receive_mp_frame(ppp, skb, pch);
2355                 else
2356 #endif /* CONFIG_PPP_MULTILINK */
2357                         ppp_receive_nonmp_frame(ppp, skb);
2358         } else {
2359                 kfree_skb(skb);
2360                 ppp_receive_error(ppp);
2361         }
2362 }
2363
2364 static void
2365 ppp_receive_error(struct ppp *ppp)
2366 {
2367         ++ppp->dev->stats.rx_errors;
2368         if (ppp->vj)
2369                 slhc_toss(ppp->vj);
2370 }
2371
2372 static void
2373 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2374 {
2375         struct sk_buff *ns;
2376         int proto, len, npi;
2377
2378         /*
2379          * Decompress the frame, if compressed.
2380          * Note that some decompressors need to see uncompressed frames
2381          * that come in as well as compressed frames.
2382          */
2383         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2384             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2385                 skb = ppp_decompress_frame(ppp, skb);
2386
2387         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2388                 goto err;
2389
2390         /* At this point the "Protocol" field MUST be decompressed, either in
2391          * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2392          */
2393         proto = PPP_PROTO(skb);
2394         switch (proto) {
2395         case PPP_VJC_COMP:
2396                 /* decompress VJ compressed packets */
2397                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2398                         goto err;
2399
2400                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2401                         /* copy to a new sk_buff with more tailroom */
2402                         ns = dev_alloc_skb(skb->len + 128);
2403                         if (!ns) {
2404                                 netdev_err(ppp->dev, "PPP: no memory "
2405                                            "(VJ decomp)\n");
2406                                 goto err;
2407                         }
2408                         skb_reserve(ns, 2);
2409                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2410                         consume_skb(skb);
2411                         skb = ns;
2412                 }
2413                 else
2414                         skb->ip_summed = CHECKSUM_NONE;
2415
2416                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2417                 if (len <= 0) {
2418                         netdev_printk(KERN_DEBUG, ppp->dev,
2419                                       "PPP: VJ decompression error\n");
2420                         goto err;
2421                 }
2422                 len += 2;
2423                 if (len > skb->len)
2424                         skb_put(skb, len - skb->len);
2425                 else if (len < skb->len)
2426                         skb_trim(skb, len);
2427                 proto = PPP_IP;
2428                 break;
2429
2430         case PPP_VJC_UNCOMP:
2431                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2432                         goto err;
2433
2434                 /* Until we fix the decompressor need to make sure
2435                  * data portion is linear.
2436                  */
2437                 if (!pskb_may_pull(skb, skb->len))
2438                         goto err;
2439
2440                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2441                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2442                         goto err;
2443                 }
2444                 proto = PPP_IP;
2445                 break;
2446
2447         case PPP_CCP:
2448                 ppp_ccp_peek(ppp, skb, 1);
2449                 break;
2450         }
2451
2452         ++ppp->stats64.rx_packets;
2453         ppp->stats64.rx_bytes += skb->len - 2;
2454
2455         npi = proto_to_npindex(proto);
2456         if (npi < 0) {
2457                 /* control or unknown frame - pass it to pppd */
2458                 skb_queue_tail(&ppp->file.rq, skb);
2459                 /* limit queue length by dropping old frames */
2460                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2461                        (skb = skb_dequeue(&ppp->file.rq)))
2462                         kfree_skb(skb);
2463                 /* wake up any process polling or blocking on read */
2464                 wake_up_interruptible(&ppp->file.rwait);
2465
2466         } else {
2467                 /* network protocol frame - give it to the kernel */
2468
2469 #ifdef CONFIG_PPP_FILTER
2470                 /* check if the packet passes the pass and active filters */
2471                 /* the filter instructions are constructed assuming
2472                    a four-byte PPP header on each packet */
2473                 if (ppp->pass_filter || ppp->active_filter) {
2474                         if (skb_unclone(skb, GFP_ATOMIC))
2475                                 goto err;
2476
2477                         *(u8 *)skb_push(skb, 2) = 0;
2478                         if (ppp->pass_filter &&
2479                             bpf_prog_run(ppp->pass_filter, skb) == 0) {
2480                                 if (ppp->debug & 1)
2481                                         netdev_printk(KERN_DEBUG, ppp->dev,
2482                                                       "PPP: inbound frame "
2483                                                       "not passed\n");
2484                                 kfree_skb(skb);
2485                                 return;
2486                         }
2487                         if (!(ppp->active_filter &&
2488                               bpf_prog_run(ppp->active_filter, skb) == 0))
2489                                 ppp->last_recv = jiffies;
2490                         __skb_pull(skb, 2);
2491                 } else
2492 #endif /* CONFIG_PPP_FILTER */
2493                         ppp->last_recv = jiffies;
2494
2495                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2496                     ppp->npmode[npi] != NPMODE_PASS) {
2497                         kfree_skb(skb);
2498                 } else {
2499                         /* chop off protocol */
2500                         skb_pull_rcsum(skb, 2);
2501                         skb->dev = ppp->dev;
2502                         skb->protocol = htons(npindex_to_ethertype[npi]);
2503                         skb_reset_mac_header(skb);
2504                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2505                                                       dev_net(ppp->dev)));
2506                         netif_rx(skb);
2507                 }
2508         }
2509         return;
2510
2511  err:
2512         kfree_skb(skb);
2513         ppp_receive_error(ppp);
2514 }
2515
2516 static struct sk_buff *
2517 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2518 {
2519         int proto = PPP_PROTO(skb);
2520         struct sk_buff *ns;
2521         int len;
2522
2523         /* Until we fix all the decompressor's need to make sure
2524          * data portion is linear.
2525          */
2526         if (!pskb_may_pull(skb, skb->len))
2527                 goto err;
2528
2529         if (proto == PPP_COMP) {
2530                 int obuff_size;
2531
2532                 switch(ppp->rcomp->compress_proto) {
2533                 case CI_MPPE:
2534                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2535                         break;
2536                 default:
2537                         obuff_size = ppp->mru + PPP_HDRLEN;
2538                         break;
2539                 }
2540
2541                 ns = dev_alloc_skb(obuff_size);
2542                 if (!ns) {
2543                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2544                                    "no memory\n");
2545                         goto err;
2546                 }
2547                 /* the decompressor still expects the A/C bytes in the hdr */
2548                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2549                                 skb->len + 2, ns->data, obuff_size);
2550                 if (len < 0) {
2551                         /* Pass the compressed frame to pppd as an
2552                            error indication. */
2553                         if (len == DECOMP_FATALERROR)
2554                                 ppp->rstate |= SC_DC_FERROR;
2555                         kfree_skb(ns);
2556                         goto err;
2557                 }
2558
2559                 consume_skb(skb);
2560                 skb = ns;
2561                 skb_put(skb, len);
2562                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2563
2564                 /* Don't call __ppp_decompress_proto() here, but instead rely on
2565                  * corresponding algo (mppe/bsd/deflate) to decompress it.
2566                  */
2567         } else {
2568                 /* Uncompressed frame - pass to decompressor so it
2569                    can update its dictionary if necessary. */
2570                 if (ppp->rcomp->incomp)
2571                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2572                                            skb->len + 2);
2573         }
2574
2575         return skb;
2576
2577  err:
2578         ppp->rstate |= SC_DC_ERROR;
2579         ppp_receive_error(ppp);
2580         return skb;
2581 }
2582
2583 #ifdef CONFIG_PPP_MULTILINK
2584 /*
2585  * Receive a multilink frame.
2586  * We put it on the reconstruction queue and then pull off
2587  * as many completed frames as we can.
2588  */
2589 static void
2590 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2591 {
2592         u32 mask, seq;
2593         struct channel *ch;
2594         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2595
2596         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2597                 goto err;               /* no good, throw it away */
2598
2599         /* Decode sequence number and begin/end bits */
2600         if (ppp->flags & SC_MP_SHORTSEQ) {
2601                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2602                 mask = 0xfff;
2603         } else {
2604                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2605                 mask = 0xffffff;
2606         }
2607         PPP_MP_CB(skb)->BEbits = skb->data[2];
2608         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2609
2610         /*
2611          * Do protocol ID decompression on the first fragment of each packet.
2612          * We have to do that here, because ppp_receive_nonmp_frame() expects
2613          * decompressed protocol field.
2614          */
2615         if (PPP_MP_CB(skb)->BEbits & B)
2616                 __ppp_decompress_proto(skb);
2617
2618         /*
2619          * Expand sequence number to 32 bits, making it as close
2620          * as possible to ppp->minseq.
2621          */
2622         seq |= ppp->minseq & ~mask;
2623         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2624                 seq += mask + 1;
2625         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2626                 seq -= mask + 1;        /* should never happen */
2627         PPP_MP_CB(skb)->sequence = seq;
2628         pch->lastseq = seq;
2629
2630         /*
2631          * If this packet comes before the next one we were expecting,
2632          * drop it.
2633          */
2634         if (seq_before(seq, ppp->nextseq)) {
2635                 kfree_skb(skb);
2636                 ++ppp->dev->stats.rx_dropped;
2637                 ppp_receive_error(ppp);
2638                 return;
2639         }
2640
2641         /*
2642          * Reevaluate minseq, the minimum over all channels of the
2643          * last sequence number received on each channel.  Because of
2644          * the increasing sequence number rule, we know that any fragment
2645          * before `minseq' which hasn't arrived is never going to arrive.
2646          * The list of channels can't change because we have the receive
2647          * side of the ppp unit locked.
2648          */
2649         list_for_each_entry(ch, &ppp->channels, clist) {
2650                 if (seq_before(ch->lastseq, seq))
2651                         seq = ch->lastseq;
2652         }
2653         if (seq_before(ppp->minseq, seq))
2654                 ppp->minseq = seq;
2655
2656         /* Put the fragment on the reconstruction queue */
2657         ppp_mp_insert(ppp, skb);
2658
2659         /* If the queue is getting long, don't wait any longer for packets
2660            before the start of the queue. */
2661         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2662                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2663                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2664                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2665         }
2666
2667         /* Pull completed packets off the queue and receive them. */
2668         while ((skb = ppp_mp_reconstruct(ppp))) {
2669                 if (pskb_may_pull(skb, 2))
2670                         ppp_receive_nonmp_frame(ppp, skb);
2671                 else {
2672                         ++ppp->dev->stats.rx_length_errors;
2673                         kfree_skb(skb);
2674                         ppp_receive_error(ppp);
2675                 }
2676         }
2677
2678         return;
2679
2680  err:
2681         kfree_skb(skb);
2682         ppp_receive_error(ppp);
2683 }
2684
2685 /*
2686  * Insert a fragment on the MP reconstruction queue.
2687  * The queue is ordered by increasing sequence number.
2688  */
2689 static void
2690 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2691 {
2692         struct sk_buff *p;
2693         struct sk_buff_head *list = &ppp->mrq;
2694         u32 seq = PPP_MP_CB(skb)->sequence;
2695
2696         /* N.B. we don't need to lock the list lock because we have the
2697            ppp unit receive-side lock. */
2698         skb_queue_walk(list, p) {
2699                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2700                         break;
2701         }
2702         __skb_queue_before(list, p, skb);
2703 }
2704
2705 /*
2706  * Reconstruct a packet from the MP fragment queue.
2707  * We go through increasing sequence numbers until we find a
2708  * complete packet, or we get to the sequence number for a fragment
2709  * which hasn't arrived but might still do so.
2710  */
2711 static struct sk_buff *
2712 ppp_mp_reconstruct(struct ppp *ppp)
2713 {
2714         u32 seq = ppp->nextseq;
2715         u32 minseq = ppp->minseq;
2716         struct sk_buff_head *list = &ppp->mrq;
2717         struct sk_buff *p, *tmp;
2718         struct sk_buff *head, *tail;
2719         struct sk_buff *skb = NULL;
2720         int lost = 0, len = 0;
2721
2722         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2723                 return NULL;
2724         head = __skb_peek(list);
2725         tail = NULL;
2726         skb_queue_walk_safe(list, p, tmp) {
2727         again:
2728                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2729                         /* this can't happen, anyway ignore the skb */
2730                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2731                                    "seq %u < %u\n",
2732                                    PPP_MP_CB(p)->sequence, seq);
2733                         __skb_unlink(p, list);
2734                         kfree_skb(p);
2735                         continue;
2736                 }
2737                 if (PPP_MP_CB(p)->sequence != seq) {
2738                         u32 oldseq;
2739                         /* Fragment `seq' is missing.  If it is after
2740                            minseq, it might arrive later, so stop here. */
2741                         if (seq_after(seq, minseq))
2742                                 break;
2743                         /* Fragment `seq' is lost, keep going. */
2744                         lost = 1;
2745                         oldseq = seq;
2746                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2747                                 minseq + 1: PPP_MP_CB(p)->sequence;
2748
2749                         if (ppp->debug & 1)
2750                                 netdev_printk(KERN_DEBUG, ppp->dev,
2751                                               "lost frag %u..%u\n",
2752                                               oldseq, seq-1);
2753
2754                         goto again;
2755                 }
2756
2757                 /*
2758                  * At this point we know that all the fragments from
2759                  * ppp->nextseq to seq are either present or lost.
2760                  * Also, there are no complete packets in the queue
2761                  * that have no missing fragments and end before this
2762                  * fragment.
2763                  */
2764
2765                 /* B bit set indicates this fragment starts a packet */
2766                 if (PPP_MP_CB(p)->BEbits & B) {
2767                         head = p;
2768                         lost = 0;
2769                         len = 0;
2770                 }
2771
2772                 len += p->len;
2773
2774                 /* Got a complete packet yet? */
2775                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2776                     (PPP_MP_CB(head)->BEbits & B)) {
2777                         if (len > ppp->mrru + 2) {
2778                                 ++ppp->dev->stats.rx_length_errors;
2779                                 netdev_printk(KERN_DEBUG, ppp->dev,
2780                                               "PPP: reconstructed packet"
2781                                               " is too long (%d)\n", len);
2782                         } else {
2783                                 tail = p;
2784                                 break;
2785                         }
2786                         ppp->nextseq = seq + 1;
2787                 }
2788
2789                 /*
2790                  * If this is the ending fragment of a packet,
2791                  * and we haven't found a complete valid packet yet,
2792                  * we can discard up to and including this fragment.
2793                  */
2794                 if (PPP_MP_CB(p)->BEbits & E) {
2795                         struct sk_buff *tmp2;
2796
2797                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2798                                 if (ppp->debug & 1)
2799                                         netdev_printk(KERN_DEBUG, ppp->dev,
2800                                                       "discarding frag %u\n",
2801                                                       PPP_MP_CB(p)->sequence);
2802                                 __skb_unlink(p, list);
2803                                 kfree_skb(p);
2804                         }
2805                         head = skb_peek(list);
2806                         if (!head)
2807                                 break;
2808                 }
2809                 ++seq;
2810         }
2811
2812         /* If we have a complete packet, copy it all into one skb. */
2813         if (tail != NULL) {
2814                 /* If we have discarded any fragments,
2815                    signal a receive error. */
2816                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2817                         skb_queue_walk_safe(list, p, tmp) {
2818                                 if (p == head)
2819                                         break;
2820                                 if (ppp->debug & 1)
2821                                         netdev_printk(KERN_DEBUG, ppp->dev,
2822                                                       "discarding frag %u\n",
2823                                                       PPP_MP_CB(p)->sequence);
2824                                 __skb_unlink(p, list);
2825                                 kfree_skb(p);
2826                         }
2827
2828                         if (ppp->debug & 1)
2829                                 netdev_printk(KERN_DEBUG, ppp->dev,
2830                                               "  missed pkts %u..%u\n",
2831                                               ppp->nextseq,
2832                                               PPP_MP_CB(head)->sequence-1);
2833                         ++ppp->dev->stats.rx_dropped;
2834                         ppp_receive_error(ppp);
2835                 }
2836
2837                 skb = head;
2838                 if (head != tail) {
2839                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2840                         p = skb_queue_next(list, head);
2841                         __skb_unlink(skb, list);
2842                         skb_queue_walk_from_safe(list, p, tmp) {
2843                                 __skb_unlink(p, list);
2844                                 *fragpp = p;
2845                                 p->next = NULL;
2846                                 fragpp = &p->next;
2847
2848                                 skb->len += p->len;
2849                                 skb->data_len += p->len;
2850                                 skb->truesize += p->truesize;
2851
2852                                 if (p == tail)
2853                                         break;
2854                         }
2855                 } else {
2856                         __skb_unlink(skb, list);
2857                 }
2858
2859                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2860         }
2861
2862         return skb;
2863 }
2864 #endif /* CONFIG_PPP_MULTILINK */
2865
2866 /*
2867  * Channel interface.
2868  */
2869
2870 /* Create a new, unattached ppp channel. */
2871 int ppp_register_channel(struct ppp_channel *chan)
2872 {
2873         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2874 }
2875
2876 /* Create a new, unattached ppp channel for specified net. */
2877 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2878 {
2879         struct channel *pch;
2880         struct ppp_net *pn;
2881
2882         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2883         if (!pch)
2884                 return -ENOMEM;
2885
2886         pn = ppp_pernet(net);
2887
2888         pch->ppp = NULL;
2889         pch->chan = chan;
2890         pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
2891         chan->ppp = pch;
2892         init_ppp_file(&pch->file, CHANNEL);
2893         pch->file.hdrlen = chan->hdrlen;
2894 #ifdef CONFIG_PPP_MULTILINK
2895         pch->lastseq = -1;
2896 #endif /* CONFIG_PPP_MULTILINK */
2897         init_rwsem(&pch->chan_sem);
2898         spin_lock_init(&pch->downl);
2899         rwlock_init(&pch->upl);
2900
2901         spin_lock_bh(&pn->all_channels_lock);
2902         pch->file.index = ++pn->last_channel_index;
2903         list_add(&pch->list, &pn->new_channels);
2904         atomic_inc(&channel_count);
2905         spin_unlock_bh(&pn->all_channels_lock);
2906
2907         return 0;
2908 }
2909
2910 /*
2911  * Return the index of a channel.
2912  */
2913 int ppp_channel_index(struct ppp_channel *chan)
2914 {
2915         struct channel *pch = chan->ppp;
2916
2917         if (pch)
2918                 return pch->file.index;
2919         return -1;
2920 }
2921
2922 /*
2923  * Return the PPP unit number to which a channel is connected.
2924  */
2925 int ppp_unit_number(struct ppp_channel *chan)
2926 {
2927         struct channel *pch = chan->ppp;
2928         int unit = -1;
2929
2930         if (pch) {
2931                 read_lock_bh(&pch->upl);
2932                 if (pch->ppp)
2933                         unit = pch->ppp->file.index;
2934                 read_unlock_bh(&pch->upl);
2935         }
2936         return unit;
2937 }
2938
2939 /*
2940  * Return the PPP device interface name of a channel.
2941  */
2942 char *ppp_dev_name(struct ppp_channel *chan)
2943 {
2944         struct channel *pch = chan->ppp;
2945         char *name = NULL;
2946
2947         if (pch) {
2948                 read_lock_bh(&pch->upl);
2949                 if (pch->ppp && pch->ppp->dev)
2950                         name = pch->ppp->dev->name;
2951                 read_unlock_bh(&pch->upl);
2952         }
2953         return name;
2954 }
2955
2956
2957 /*
2958  * Disconnect a channel from the generic layer.
2959  * This must be called in process context.
2960  */
2961 void
2962 ppp_unregister_channel(struct ppp_channel *chan)
2963 {
2964         struct channel *pch = chan->ppp;
2965         struct ppp_net *pn;
2966
2967         if (!pch)
2968                 return;         /* should never happen */
2969
2970         chan->ppp = NULL;
2971
2972         /*
2973          * This ensures that we have returned from any calls into
2974          * the channel's start_xmit or ioctl routine before we proceed.
2975          */
2976         down_write(&pch->chan_sem);
2977         spin_lock_bh(&pch->downl);
2978         pch->chan = NULL;
2979         spin_unlock_bh(&pch->downl);
2980         up_write(&pch->chan_sem);
2981         ppp_disconnect_channel(pch);
2982
2983         pn = ppp_pernet(pch->chan_net);
2984         spin_lock_bh(&pn->all_channels_lock);
2985         list_del(&pch->list);
2986         spin_unlock_bh(&pn->all_channels_lock);
2987
2988         ppp_unbridge_channels(pch);
2989
2990         pch->file.dead = 1;
2991         wake_up_interruptible(&pch->file.rwait);
2992
2993         if (refcount_dec_and_test(&pch->file.refcnt))
2994                 ppp_destroy_channel(pch);
2995 }
2996
2997 /*
2998  * Callback from a channel when it can accept more to transmit.
2999  * This should be called at BH/softirq level, not interrupt level.
3000  */
3001 void
3002 ppp_output_wakeup(struct ppp_channel *chan)
3003 {
3004         struct channel *pch = chan->ppp;
3005
3006         if (!pch)
3007                 return;
3008         ppp_channel_push(pch);
3009 }
3010
3011 /*
3012  * Compression control.
3013  */
3014
3015 /* Process the PPPIOCSCOMPRESS ioctl. */
3016 static int
3017 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3018 {
3019         int err = -EFAULT;
3020         struct compressor *cp, *ocomp;
3021         void *state, *ostate;
3022         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3023
3024         if (data->length > CCP_MAX_OPTION_LENGTH)
3025                 goto out;
3026         if (copy_from_user(ccp_option, data->ptr, data->length))
3027                 goto out;
3028
3029         err = -EINVAL;
3030         if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3031                 goto out;
3032
3033         cp = try_then_request_module(
3034                 find_compressor(ccp_option[0]),
3035                 "ppp-compress-%d", ccp_option[0]);
3036         if (!cp)
3037                 goto out;
3038
3039         err = -ENOBUFS;
3040         if (data->transmit) {
3041                 state = cp->comp_alloc(ccp_option, data->length);
3042                 if (state) {
3043                         ppp_xmit_lock(ppp);
3044                         ppp->xstate &= ~SC_COMP_RUN;
3045                         ocomp = ppp->xcomp;
3046                         ostate = ppp->xc_state;
3047                         ppp->xcomp = cp;
3048                         ppp->xc_state = state;
3049                         ppp_xmit_unlock(ppp);
3050                         if (ostate) {
3051                                 ocomp->comp_free(ostate);
3052                                 module_put(ocomp->owner);
3053                         }
3054                         err = 0;
3055                 } else
3056                         module_put(cp->owner);
3057
3058         } else {
3059                 state = cp->decomp_alloc(ccp_option, data->length);
3060                 if (state) {
3061                         ppp_recv_lock(ppp);
3062                         ppp->rstate &= ~SC_DECOMP_RUN;
3063                         ocomp = ppp->rcomp;
3064                         ostate = ppp->rc_state;
3065                         ppp->rcomp = cp;
3066                         ppp->rc_state = state;
3067                         ppp_recv_unlock(ppp);
3068                         if (ostate) {
3069                                 ocomp->decomp_free(ostate);
3070                                 module_put(ocomp->owner);
3071                         }
3072                         err = 0;
3073                 } else
3074                         module_put(cp->owner);
3075         }
3076
3077  out:
3078         return err;
3079 }
3080
3081 /*
3082  * Look at a CCP packet and update our state accordingly.
3083  * We assume the caller has the xmit or recv path locked.
3084  */
3085 static void
3086 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3087 {
3088         unsigned char *dp;
3089         int len;
3090
3091         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3092                 return; /* no header */
3093         dp = skb->data + 2;
3094
3095         switch (CCP_CODE(dp)) {
3096         case CCP_CONFREQ:
3097
3098                 /* A ConfReq starts negotiation of compression
3099                  * in one direction of transmission,
3100                  * and hence brings it down...but which way?
3101                  *
3102                  * Remember:
3103                  * A ConfReq indicates what the sender would like to receive
3104                  */
3105                 if(inbound)
3106                         /* He is proposing what I should send */
3107                         ppp->xstate &= ~SC_COMP_RUN;
3108                 else
3109                         /* I am proposing to what he should send */
3110                         ppp->rstate &= ~SC_DECOMP_RUN;
3111
3112                 break;
3113
3114         case CCP_TERMREQ:
3115         case CCP_TERMACK:
3116                 /*
3117                  * CCP is going down, both directions of transmission
3118                  */
3119                 ppp->rstate &= ~SC_DECOMP_RUN;
3120                 ppp->xstate &= ~SC_COMP_RUN;
3121                 break;
3122
3123         case CCP_CONFACK:
3124                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3125                         break;
3126                 len = CCP_LENGTH(dp);
3127                 if (!pskb_may_pull(skb, len + 2))
3128                         return;         /* too short */
3129                 dp += CCP_HDRLEN;
3130                 len -= CCP_HDRLEN;
3131                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3132                         break;
3133                 if (inbound) {
3134                         /* we will start receiving compressed packets */
3135                         if (!ppp->rc_state)
3136                                 break;
3137                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3138                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
3139                                 ppp->rstate |= SC_DECOMP_RUN;
3140                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3141                         }
3142                 } else {
3143                         /* we will soon start sending compressed packets */
3144                         if (!ppp->xc_state)
3145                                 break;
3146                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3147                                         ppp->file.index, 0, ppp->debug))
3148                                 ppp->xstate |= SC_COMP_RUN;
3149                 }
3150                 break;
3151
3152         case CCP_RESETACK:
3153                 /* reset the [de]compressor */
3154                 if ((ppp->flags & SC_CCP_UP) == 0)
3155                         break;
3156                 if (inbound) {
3157                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3158                                 ppp->rcomp->decomp_reset(ppp->rc_state);
3159                                 ppp->rstate &= ~SC_DC_ERROR;
3160                         }
3161                 } else {
3162                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3163                                 ppp->xcomp->comp_reset(ppp->xc_state);
3164                 }
3165                 break;
3166         }
3167 }
3168
3169 /* Free up compression resources. */
3170 static void
3171 ppp_ccp_closed(struct ppp *ppp)
3172 {
3173         void *xstate, *rstate;
3174         struct compressor *xcomp, *rcomp;
3175
3176         ppp_lock(ppp);
3177         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3178         ppp->xstate = 0;
3179         xcomp = ppp->xcomp;
3180         xstate = ppp->xc_state;
3181         ppp->xc_state = NULL;
3182         ppp->rstate = 0;
3183         rcomp = ppp->rcomp;
3184         rstate = ppp->rc_state;
3185         ppp->rc_state = NULL;
3186         ppp_unlock(ppp);
3187
3188         if (xstate) {
3189                 xcomp->comp_free(xstate);
3190                 module_put(xcomp->owner);
3191         }
3192         if (rstate) {
3193                 rcomp->decomp_free(rstate);
3194                 module_put(rcomp->owner);
3195         }
3196 }
3197
3198 /* List of compressors. */
3199 static LIST_HEAD(compressor_list);
3200 static DEFINE_SPINLOCK(compressor_list_lock);
3201
3202 struct compressor_entry {
3203         struct list_head list;
3204         struct compressor *comp;
3205 };
3206
3207 static struct compressor_entry *
3208 find_comp_entry(int proto)
3209 {
3210         struct compressor_entry *ce;
3211
3212         list_for_each_entry(ce, &compressor_list, list) {
3213                 if (ce->comp->compress_proto == proto)
3214                         return ce;
3215         }
3216         return NULL;
3217 }
3218
3219 /* Register a compressor */
3220 int
3221 ppp_register_compressor(struct compressor *cp)
3222 {
3223         struct compressor_entry *ce;
3224         int ret;
3225         spin_lock(&compressor_list_lock);
3226         ret = -EEXIST;
3227         if (find_comp_entry(cp->compress_proto))
3228                 goto out;
3229         ret = -ENOMEM;
3230         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3231         if (!ce)
3232                 goto out;
3233         ret = 0;
3234         ce->comp = cp;
3235         list_add(&ce->list, &compressor_list);
3236  out:
3237         spin_unlock(&compressor_list_lock);
3238         return ret;
3239 }
3240
3241 /* Unregister a compressor */
3242 void
3243 ppp_unregister_compressor(struct compressor *cp)
3244 {
3245         struct compressor_entry *ce;
3246
3247         spin_lock(&compressor_list_lock);
3248         ce = find_comp_entry(cp->compress_proto);
3249         if (ce && ce->comp == cp) {
3250                 list_del(&ce->list);
3251                 kfree(ce);
3252         }
3253         spin_unlock(&compressor_list_lock);
3254 }
3255
3256 /* Find a compressor. */
3257 static struct compressor *
3258 find_compressor(int type)
3259 {
3260         struct compressor_entry *ce;
3261         struct compressor *cp = NULL;
3262
3263         spin_lock(&compressor_list_lock);
3264         ce = find_comp_entry(type);
3265         if (ce) {
3266                 cp = ce->comp;
3267                 if (!try_module_get(cp->owner))
3268                         cp = NULL;
3269         }
3270         spin_unlock(&compressor_list_lock);
3271         return cp;
3272 }
3273
3274 /*
3275  * Miscelleneous stuff.
3276  */
3277
3278 static void
3279 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3280 {
3281         struct slcompress *vj = ppp->vj;
3282
3283         memset(st, 0, sizeof(*st));
3284         st->p.ppp_ipackets = ppp->stats64.rx_packets;
3285         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3286         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3287         st->p.ppp_opackets = ppp->stats64.tx_packets;
3288         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3289         st->p.ppp_obytes = ppp->stats64.tx_bytes;
3290         if (!vj)
3291                 return;
3292         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3293         st->vj.vjs_compressed = vj->sls_o_compressed;
3294         st->vj.vjs_searches = vj->sls_o_searches;
3295         st->vj.vjs_misses = vj->sls_o_misses;
3296         st->vj.vjs_errorin = vj->sls_i_error;
3297         st->vj.vjs_tossed = vj->sls_i_tossed;
3298         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3299         st->vj.vjs_compressedin = vj->sls_i_compressed;
3300 }
3301
3302 /*
3303  * Stuff for handling the lists of ppp units and channels
3304  * and for initialization.
3305  */
3306
3307 /*
3308  * Create a new ppp interface unit.  Fails if it can't allocate memory
3309  * or if there is already a unit with the requested number.
3310  * unit == -1 means allocate a new number.
3311  */
3312 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3313 {
3314         struct ppp_config conf = {
3315                 .file = file,
3316                 .unit = *unit,
3317                 .ifname_is_set = false,
3318         };
3319         struct net_device *dev;
3320         struct ppp *ppp;
3321         int err;
3322
3323         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3324         if (!dev) {
3325                 err = -ENOMEM;
3326                 goto err;
3327         }
3328         dev_net_set(dev, net);
3329         dev->rtnl_link_ops = &ppp_link_ops;
3330
3331         rtnl_lock();
3332
3333         err = ppp_dev_configure(net, dev, &conf);
3334         if (err < 0)
3335                 goto err_dev;
3336         ppp = netdev_priv(dev);
3337         *unit = ppp->file.index;
3338
3339         rtnl_unlock();
3340
3341         return 0;
3342
3343 err_dev:
3344         rtnl_unlock();
3345         free_netdev(dev);
3346 err:
3347         return err;
3348 }
3349
3350 /*
3351  * Initialize a ppp_file structure.
3352  */
3353 static void
3354 init_ppp_file(struct ppp_file *pf, int kind)
3355 {
3356         pf->kind = kind;
3357         skb_queue_head_init(&pf->xq);
3358         skb_queue_head_init(&pf->rq);
3359         refcount_set(&pf->refcnt, 1);
3360         init_waitqueue_head(&pf->rwait);
3361 }
3362
3363 /*
3364  * Free the memory used by a ppp unit.  This is only called once
3365  * there are no channels connected to the unit and no file structs
3366  * that reference the unit.
3367  */
3368 static void ppp_destroy_interface(struct ppp *ppp)
3369 {
3370         atomic_dec(&ppp_unit_count);
3371
3372         if (!ppp->file.dead || ppp->n_channels) {
3373                 /* "can't happen" */
3374                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3375                            "but dead=%d n_channels=%d !\n",
3376                            ppp, ppp->file.dead, ppp->n_channels);
3377                 return;
3378         }
3379
3380         ppp_ccp_closed(ppp);
3381         if (ppp->vj) {
3382                 slhc_free(ppp->vj);
3383                 ppp->vj = NULL;
3384         }
3385         skb_queue_purge(&ppp->file.xq);
3386         skb_queue_purge(&ppp->file.rq);
3387 #ifdef CONFIG_PPP_MULTILINK
3388         skb_queue_purge(&ppp->mrq);
3389 #endif /* CONFIG_PPP_MULTILINK */
3390 #ifdef CONFIG_PPP_FILTER
3391         if (ppp->pass_filter) {
3392                 bpf_prog_destroy(ppp->pass_filter);
3393                 ppp->pass_filter = NULL;
3394         }
3395
3396         if (ppp->active_filter) {
3397                 bpf_prog_destroy(ppp->active_filter);
3398                 ppp->active_filter = NULL;
3399         }
3400 #endif /* CONFIG_PPP_FILTER */
3401
3402         kfree_skb(ppp->xmit_pending);
3403         free_percpu(ppp->xmit_recursion);
3404
3405         free_netdev(ppp->dev);
3406 }
3407
3408 /*
3409  * Locate an existing ppp unit.
3410  * The caller should have locked the all_ppp_mutex.
3411  */
3412 static struct ppp *
3413 ppp_find_unit(struct ppp_net *pn, int unit)
3414 {
3415         return unit_find(&pn->units_idr, unit);
3416 }
3417
3418 /*
3419  * Locate an existing ppp channel.
3420  * The caller should have locked the all_channels_lock.
3421  * First we look in the new_channels list, then in the
3422  * all_channels list.  If found in the new_channels list,
3423  * we move it to the all_channels list.  This is for speed
3424  * when we have a lot of channels in use.
3425  */
3426 static struct channel *
3427 ppp_find_channel(struct ppp_net *pn, int unit)
3428 {
3429         struct channel *pch;
3430
3431         list_for_each_entry(pch, &pn->new_channels, list) {
3432                 if (pch->file.index == unit) {
3433                         list_move(&pch->list, &pn->all_channels);
3434                         return pch;
3435                 }
3436         }
3437
3438         list_for_each_entry(pch, &pn->all_channels, list) {
3439                 if (pch->file.index == unit)
3440                         return pch;
3441         }
3442
3443         return NULL;
3444 }
3445
3446 /*
3447  * Connect a PPP channel to a PPP interface unit.
3448  */
3449 static int
3450 ppp_connect_channel(struct channel *pch, int unit)
3451 {
3452         struct ppp *ppp;
3453         struct ppp_net *pn;
3454         int ret = -ENXIO;
3455         int hdrlen;
3456
3457         pn = ppp_pernet(pch->chan_net);
3458
3459         mutex_lock(&pn->all_ppp_mutex);
3460         ppp = ppp_find_unit(pn, unit);
3461         if (!ppp)
3462                 goto out;
3463         write_lock_bh(&pch->upl);
3464         ret = -EINVAL;
3465         if (pch->ppp ||
3466             rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3467                 goto outl;
3468
3469         ppp_lock(ppp);
3470         spin_lock_bh(&pch->downl);
3471         if (!pch->chan) {
3472                 /* Don't connect unregistered channels */
3473                 spin_unlock_bh(&pch->downl);
3474                 ppp_unlock(ppp);
3475                 ret = -ENOTCONN;
3476                 goto outl;
3477         }
3478         spin_unlock_bh(&pch->downl);
3479         if (pch->file.hdrlen > ppp->file.hdrlen)
3480                 ppp->file.hdrlen = pch->file.hdrlen;
3481         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3482         if (hdrlen > ppp->dev->hard_header_len)
3483                 ppp->dev->hard_header_len = hdrlen;
3484         list_add_tail(&pch->clist, &ppp->channels);
3485         ++ppp->n_channels;
3486         pch->ppp = ppp;
3487         refcount_inc(&ppp->file.refcnt);
3488         ppp_unlock(ppp);
3489         ret = 0;
3490
3491  outl:
3492         write_unlock_bh(&pch->upl);
3493  out:
3494         mutex_unlock(&pn->all_ppp_mutex);
3495         return ret;
3496 }
3497
3498 /*
3499  * Disconnect a channel from its ppp unit.
3500  */
3501 static int
3502 ppp_disconnect_channel(struct channel *pch)
3503 {
3504         struct ppp *ppp;
3505         int err = -EINVAL;
3506
3507         write_lock_bh(&pch->upl);
3508         ppp = pch->ppp;
3509         pch->ppp = NULL;
3510         write_unlock_bh(&pch->upl);
3511         if (ppp) {
3512                 /* remove it from the ppp unit's list */
3513                 ppp_lock(ppp);
3514                 list_del(&pch->clist);
3515                 if (--ppp->n_channels == 0)
3516                         wake_up_interruptible(&ppp->file.rwait);
3517                 ppp_unlock(ppp);
3518                 if (refcount_dec_and_test(&ppp->file.refcnt))
3519                         ppp_destroy_interface(ppp);
3520                 err = 0;
3521         }
3522         return err;
3523 }
3524
3525 /*
3526  * Free up the resources used by a ppp channel.
3527  */
3528 static void ppp_destroy_channel(struct channel *pch)
3529 {
3530         put_net_track(pch->chan_net, &pch->ns_tracker);
3531         pch->chan_net = NULL;
3532
3533         atomic_dec(&channel_count);
3534
3535         if (!pch->file.dead) {
3536                 /* "can't happen" */
3537                 pr_err("ppp: destroying undead channel %p !\n", pch);
3538                 return;
3539         }
3540         skb_queue_purge(&pch->file.xq);
3541         skb_queue_purge(&pch->file.rq);
3542         kfree(pch);
3543 }
3544
3545 static void __exit ppp_cleanup(void)
3546 {
3547         /* should never happen */
3548         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3549                 pr_err("PPP: removing module but units remain!\n");
3550         rtnl_link_unregister(&ppp_link_ops);
3551         unregister_chrdev(PPP_MAJOR, "ppp");
3552         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3553         class_destroy(ppp_class);
3554         unregister_pernet_device(&ppp_net_ops);
3555 }
3556
3557 /*
3558  * Units handling. Caller must protect concurrent access
3559  * by holding all_ppp_mutex
3560  */
3561
3562 /* associate pointer with specified number */
3563 static int unit_set(struct idr *p, void *ptr, int n)
3564 {
3565         int unit;
3566
3567         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3568         if (unit == -ENOSPC)
3569                 unit = -EINVAL;
3570         return unit;
3571 }
3572
3573 /* get new free unit number and associate pointer with it */
3574 static int unit_get(struct idr *p, void *ptr, int min)
3575 {
3576         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3577 }
3578
3579 /* put unit number back to a pool */
3580 static void unit_put(struct idr *p, int n)
3581 {
3582         idr_remove(p, n);
3583 }
3584
3585 /* get pointer associated with the number */
3586 static void *unit_find(struct idr *p, int n)
3587 {
3588         return idr_find(p, n);
3589 }
3590
3591 /* Module/initialization stuff */
3592
3593 module_init(ppp_init);
3594 module_exit(ppp_cleanup);
3595
3596 EXPORT_SYMBOL(ppp_register_net_channel);
3597 EXPORT_SYMBOL(ppp_register_channel);
3598 EXPORT_SYMBOL(ppp_unregister_channel);
3599 EXPORT_SYMBOL(ppp_channel_index);
3600 EXPORT_SYMBOL(ppp_unit_number);
3601 EXPORT_SYMBOL(ppp_dev_name);
3602 EXPORT_SYMBOL(ppp_input);
3603 EXPORT_SYMBOL(ppp_input_error);
3604 EXPORT_SYMBOL(ppp_output_wakeup);
3605 EXPORT_SYMBOL(ppp_register_compressor);
3606 EXPORT_SYMBOL(ppp_unregister_compressor);
3607 MODULE_DESCRIPTION("Generic PPP layer driver");
3608 MODULE_LICENSE("GPL");
3609 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3610 MODULE_ALIAS_RTNL_LINK("ppp");
3611 MODULE_ALIAS("devname:ppp");