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