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