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