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