drivers/net/ppp/ppp_generic.c

   1 /*
   2  * Generic PPP layer for Linux.
   3  *
   4  * Copyright 1999-2002 Paul Mackerras.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  *
  11  * The generic PPP layer handles the PPP network interfaces, the
  12  * /dev/ppp device, packet and VJ compression, and multilink.
  13  * It talks to PPP `channels' via the interface defined in
  14  * include/linux/ppp_channel.h.  Channels provide the basic means for
  15  * sending and receiving PPP frames on some kind of communications
  16  * channel.
  17  *
  18  * Part of the code in this driver was inspired by the old async-only
  19  * PPP driver, written by Michael Callahan and Al Longyear, and
  20  * subsequently hacked by Paul Mackerras.
  21  *
  22  * ==FILEVERSION 20041108==
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/sched/signal.h>
  28 #include <linux/kmod.h>
  29 #include <linux/init.h>
  30 #include <linux/list.h>
  31 #include <linux/idr.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/poll.h>
  34 #include <linux/ppp_defs.h>
  35 #include <linux/filter.h>
  36 #include <linux/ppp-ioctl.h>
  37 #include <linux/ppp_channel.h>
  38 #include <linux/ppp-comp.h>
  39 #include <linux/skbuff.h>
  40 #include <linux/rtnetlink.h>
  41 #include <linux/if_arp.h>
  42 #include <linux/ip.h>
  43 #include <linux/tcp.h>
  44 #include <linux/spinlock.h>
  45 #include <linux/rwsem.h>
  46 #include <linux/stddef.h>
  47 #include <linux/device.h>
  48 #include <linux/mutex.h>
  49 #include <linux/slab.h>
  50 #include <linux/file.h>
  51 #include <asm/unaligned.h>
  52 #include <net/slhc_vj.h>
  53 #include <linux/atomic.h>
  54 #include <linux/refcount.h>
  55
  56 #include <linux/nsproxy.h>
  57 #include <net/net_namespace.h>
  58 #include <net/netns/generic.h>
  59
  60 #define PPP_VERSION     "2.4.2"
  61
  62 /*
  63  * Network protocols we support.
  64  */
  65 #define NP_IP   0               /* Internet Protocol V4 */
  66 #define NP_IPV6 1               /* Internet Protocol V6 */
  67 #define NP_IPX  2               /* IPX protocol */
  68 #define NP_AT   3               /* Appletalk protocol */
  69 #define NP_MPLS_UC 4            /* MPLS unicast */
  70 #define NP_MPLS_MC 5            /* MPLS multicast */
  71 #define NUM_NP  6               /* Number of NPs. */
  72
  73 #define MPHDRLEN        6       /* multilink protocol header length */
  74 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  75
  76 /*
  77  * An instance of /dev/ppp can be associated with either a ppp
  78  * interface unit or a ppp channel.  In both cases, file->private_data
  79  * points to one of these.
  80  */
  81 struct ppp_file {
  82         enum {
  83                 INTERFACE=1, CHANNEL
  84         }               kind;
  85         struct sk_buff_head xq;         /* pppd transmit queue */
  86         struct sk_buff_head rq;         /* receive queue for pppd */
  87         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  88         refcount_t      refcnt;         /* # refs (incl /dev/ppp attached) */
  89         int             hdrlen;         /* space to leave for headers */
  90         int             index;          /* interface unit / channel number */
  91         int             dead;           /* unit/channel has been shut down */
  92 };
  93
  94 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  95
  96 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  97 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  98
  99 /*
 100  * Data structure to hold primary network stats for which
 101  * we want to use 64 bit storage.  Other network stats
 102  * are stored in dev->stats of the ppp strucute.
 103  */
 104 struct ppp_link_stats {
 105         u64 rx_packets;
 106         u64 tx_packets;
 107         u64 rx_bytes;
 108         u64 tx_bytes;
 109 };
 110
 111 /*
 112  * Data structure describing one ppp unit.
 113  * A ppp unit corresponds to a ppp network interface device
 114  * and represents a multilink bundle.
 115  * It can have 0 or more ppp channels connected to it.
 116  */
 117 struct ppp {
 118         struct ppp_file file;           /* stuff for read/write/poll 0 */
 119         struct file     *owner;         /* file that owns this unit 48 */
 120         struct list_head channels;      /* list of attached channels 4c */
 121         int             n_channels;     /* how many channels are attached 54 */
 122         spinlock_t      rlock;          /* lock for receive side 58 */
 123         spinlock_t      wlock;          /* lock for transmit side 5c */
 124         int __percpu    *xmit_recursion; /* xmit recursion detect */
 125         int             mru;            /* max receive unit 60 */
 126         unsigned int    flags;          /* control bits 64 */
 127         unsigned int    xstate;         /* transmit state bits 68 */
 128         unsigned int    rstate;         /* receive state bits 6c */
 129         int             debug;          /* debug flags 70 */
 130         struct slcompress *vj;          /* state for VJ header compression */
 131         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 132         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 133         struct compressor *xcomp;       /* transmit packet compressor 8c */
 134         void            *xc_state;      /* its internal state 90 */
 135         struct compressor *rcomp;       /* receive decompressor 94 */
 136         void            *rc_state;      /* its internal state 98 */
 137         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 138         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 139         struct net_device *dev;         /* network interface device a4 */
 140         int             closing;        /* is device closing down? a8 */
 141 #ifdef CONFIG_PPP_MULTILINK
 142         int             nxchan;         /* next channel to send something on */
 143         u32             nxseq;          /* next sequence number to send */
 144         int             mrru;           /* MP: max reconst. receive unit */
 145         u32             nextseq;        /* MP: seq no of next packet */
 146         u32             minseq;         /* MP: min of most recent seqnos */
 147         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 148 #endif /* CONFIG_PPP_MULTILINK */
 149 #ifdef CONFIG_PPP_FILTER
 150         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 151         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 152 #endif /* CONFIG_PPP_FILTER */
 153         struct net      *ppp_net;       /* the net we belong to */
 154         struct ppp_link_stats stats64;  /* 64 bit network stats */
 155 };
 156
 157 /*
 158  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 159  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 160  * SC_MUST_COMP
 161  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 162  * Bits in xstate: SC_COMP_RUN
 163  */
 164 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 165                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 166                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 167
 168 /*
 169  * Private data structure for each channel.
 170  * This includes the data structure used for multilink.
 171  */
 172 struct channel {
 173         struct ppp_file file;           /* stuff for read/write/poll */
 174         struct list_head list;          /* link in all/new_channels list */
 175         struct ppp_channel *chan;       /* public channel data structure */
 176         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 177         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 178         struct ppp      *ppp;           /* ppp unit we're connected to */
 179         struct net      *chan_net;      /* the net channel belongs to */
 180         struct list_head clist;         /* link in list of channels per unit */
 181         rwlock_t        upl;            /* protects `ppp' */
 182 #ifdef CONFIG_PPP_MULTILINK
 183         u8              avail;          /* flag used in multilink stuff */
 184         u8              had_frag;       /* >= 1 fragments have been sent */
 185         u32             lastseq;        /* MP: last sequence # received */
 186         int             speed;          /* speed of the corresponding ppp channel*/
 187 #endif /* CONFIG_PPP_MULTILINK */
 188 };
 189
 190 struct ppp_config {
 191         struct file *file;
 192         s32 unit;
 193         bool ifname_is_set;
 194 };
 195
 196 /*
 197  * SMP locking issues:
 198  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 199  * list and the ppp.n_channels field, you need to take both locks
 200  * before you modify them.
 201  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 202  * channel.downl.
 203  */
 204
 205 static DEFINE_MUTEX(ppp_mutex);
 206 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 207 static atomic_t channel_count = ATOMIC_INIT(0);
 208
 209 /* per-net private data for this module */
 210 static unsigned int ppp_net_id __read_mostly;
 211 struct ppp_net {
 212         /* units to ppp mapping */
 213         struct idr units_idr;
 214
 215         /*
 216          * all_ppp_mutex protects the units_idr mapping.
 217          * It also ensures that finding a ppp unit in the units_idr
 218          * map and updating its file.refcnt field is atomic.
 219          */
 220         struct mutex all_ppp_mutex;
 221
 222         /* channels */
 223         struct list_head all_channels;
 224         struct list_head new_channels;
 225         int last_channel_index;
 226
 227         /*
 228          * all_channels_lock protects all_channels and
 229          * last_channel_index, and the atomicity of find
 230          * a channel and updating its file.refcnt field.
 231          */
 232         spinlock_t all_channels_lock;
 233 };
 234
 235 /* Get the PPP protocol number from a skb */
 236 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 237
 238 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 239 #define PPP_MAX_RQLEN   32
 240
 241 /*
 242  * Maximum number of multilink fragments queued up.
 243  * This has to be large enough to cope with the maximum latency of
 244  * the slowest channel relative to the others.  Strictly it should
 245  * depend on the number of channels and their characteristics.
 246  */
 247 #define PPP_MP_MAX_QLEN 128
 248
 249 /* Multilink header bits. */
 250 #define B       0x80            /* this fragment begins a packet */
 251 #define E       0x40            /* this fragment ends a packet */
 252
 253 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 254 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 255 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 256
 257 /* Prototypes. */
 258 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 259                         struct file *file, unsigned int cmd, unsigned long arg);
 260 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 261 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 262 static void ppp_push(struct ppp *ppp);
 263 static void ppp_channel_push(struct channel *pch);
 264 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 265                               struct channel *pch);
 266 static void ppp_receive_error(struct ppp *ppp);
 267 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 268 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 269                                             struct sk_buff *skb);
 270 #ifdef CONFIG_PPP_MULTILINK
 271 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 272                                 struct channel *pch);
 273 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 274 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 275 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 276 #endif /* CONFIG_PPP_MULTILINK */
 277 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 278 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 279 static void ppp_ccp_closed(struct ppp *ppp);
 280 static struct compressor *find_compressor(int type);
 281 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 282 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 283 static void init_ppp_file(struct ppp_file *pf, int kind);
 284 static void ppp_destroy_interface(struct ppp *ppp);
 285 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 286 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 287 static int ppp_connect_channel(struct channel *pch, int unit);
 288 static int ppp_disconnect_channel(struct channel *pch);
 289 static void ppp_destroy_channel(struct channel *pch);
 290 static int unit_get(struct idr *p, void *ptr, int min);
 291 static int unit_set(struct idr *p, void *ptr, int n);
 292 static void unit_put(struct idr *p, int n);
 293 static void *unit_find(struct idr *p, int n);
 294 static void ppp_setup(struct net_device *dev);
 295
 296 static const struct net_device_ops ppp_netdev_ops;
 297
 298 static struct class *ppp_class;
 299
 300 /* per net-namespace data */
 301 static inline struct ppp_net *ppp_pernet(struct net *net)
 302 {
 303         BUG_ON(!net);
 304
 305         return net_generic(net, ppp_net_id);
 306 }
 307
 308 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 309 static inline int proto_to_npindex(int proto)
 310 {
 311         switch (proto) {
 312         case PPP_IP:
 313                 return NP_IP;
 314         case PPP_IPV6:
 315                 return NP_IPV6;
 316         case PPP_IPX:
 317                 return NP_IPX;
 318         case PPP_AT:
 319                 return NP_AT;
 320         case PPP_MPLS_UC:
 321                 return NP_MPLS_UC;
 322         case PPP_MPLS_MC:
 323                 return NP_MPLS_MC;
 324         }
 325         return -EINVAL;
 326 }
 327
 328 /* Translates an NP index into a PPP protocol number */
 329 static const int npindex_to_proto[NUM_NP] = {
 330         PPP_IP,
 331         PPP_IPV6,
 332         PPP_IPX,
 333         PPP_AT,
 334         PPP_MPLS_UC,
 335         PPP_MPLS_MC,
 336 };
 337
 338 /* Translates an ethertype into an NP index */
 339 static inline int ethertype_to_npindex(int ethertype)
 340 {
 341         switch (ethertype) {
 342         case ETH_P_IP:
 343                 return NP_IP;
 344         case ETH_P_IPV6:
 345                 return NP_IPV6;
 346         case ETH_P_IPX:
 347                 return NP_IPX;
 348         case ETH_P_PPPTALK:
 349         case ETH_P_ATALK:
 350                 return NP_AT;
 351         case ETH_P_MPLS_UC:
 352                 return NP_MPLS_UC;
 353         case ETH_P_MPLS_MC:
 354                 return NP_MPLS_MC;
 355         }
 356         return -1;
 357 }
 358
 359 /* Translates an NP index into an ethertype */
 360 static const int npindex_to_ethertype[NUM_NP] = {
 361         ETH_P_IP,
 362         ETH_P_IPV6,
 363         ETH_P_IPX,
 364         ETH_P_PPPTALK,
 365         ETH_P_MPLS_UC,
 366         ETH_P_MPLS_MC,
 367 };
 368
 369 /*
 370  * Locking shorthand.
 371  */
 372 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 373 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 374 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 375 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 376 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 377                                      ppp_recv_lock(ppp); } while (0)
 378 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 379                                      ppp_xmit_unlock(ppp); } while (0)
 380
 381 /*
 382  * /dev/ppp device routines.
 383  * The /dev/ppp device is used by pppd to control the ppp unit.
 384  * It supports the read, write, ioctl and poll functions.
 385  * Open instances of /dev/ppp can be in one of three states:
 386  * unattached, attached to a ppp unit, or attached to a ppp channel.
 387  */
 388 static int ppp_open(struct inode *inode, struct file *file)
 389 {
 390         /*
 391          * This could (should?) be enforced by the permissions on /dev/ppp.
 392          */
 393         if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
 394                 return -EPERM;
 395         return 0;
 396 }
 397
 398 static int ppp_release(struct inode *unused, struct file *file)
 399 {
 400         struct ppp_file *pf = file->private_data;
 401         struct ppp *ppp;
 402
 403         if (pf) {
 404                 file->private_data = NULL;
 405                 if (pf->kind == INTERFACE) {
 406                         ppp = PF_TO_PPP(pf);
 407                         rtnl_lock();
 408                         if (file == ppp->owner)
 409                                 unregister_netdevice(ppp->dev);
 410                         rtnl_unlock();
 411                 }
 412                 if (refcount_dec_and_test(&pf->refcnt)) {
 413                         switch (pf->kind) {
 414                         case INTERFACE:
 415                                 ppp_destroy_interface(PF_TO_PPP(pf));
 416                                 break;
 417                         case CHANNEL:
 418                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 419                                 break;
 420                         }
 421                 }
 422         }
 423         return 0;
 424 }
 425
 426 static ssize_t ppp_read(struct file *file, char __user *buf,
 427                         size_t count, loff_t *ppos)
 428 {
 429         struct ppp_file *pf = file->private_data;
 430         DECLARE_WAITQUEUE(wait, current);
 431         ssize_t ret;
 432         struct sk_buff *skb = NULL;
 433         struct iovec iov;
 434         struct iov_iter to;
 435
 436         ret = count;
 437
 438         if (!pf)
 439                 return -ENXIO;
 440         add_wait_queue(&pf->rwait, &wait);
 441         for (;;) {
 442                 set_current_state(TASK_INTERRUPTIBLE);
 443                 skb = skb_dequeue(&pf->rq);
 444                 if (skb)
 445                         break;
 446                 ret = 0;
 447                 if (pf->dead)
 448                         break;
 449                 if (pf->kind == INTERFACE) {
 450                         /*
 451                          * Return 0 (EOF) on an interface that has no
 452                          * channels connected, unless it is looping
 453                          * network traffic (demand mode).
 454                          */
 455                         struct ppp *ppp = PF_TO_PPP(pf);
 456
 457                         ppp_recv_lock(ppp);
 458                         if (ppp->n_channels == 0 &&
 459                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 460                                 ppp_recv_unlock(ppp);
 461                                 break;
 462                         }
 463                         ppp_recv_unlock(ppp);
 464                 }
 465                 ret = -EAGAIN;
 466                 if (file->f_flags & O_NONBLOCK)
 467                         break;
 468                 ret = -ERESTARTSYS;
 469                 if (signal_pending(current))
 470                         break;
 471                 schedule();
 472         }
 473         set_current_state(TASK_RUNNING);
 474         remove_wait_queue(&pf->rwait, &wait);
 475
 476         if (!skb)
 477                 goto out;
 478
 479         ret = -EOVERFLOW;
 480         if (skb->len > count)
 481                 goto outf;
 482         ret = -EFAULT;
 483         iov.iov_base = buf;
 484         iov.iov_len = count;
 485         iov_iter_init(&to, READ, &iov, 1, count);
 486         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 487                 goto outf;
 488         ret = skb->len;
 489
 490  outf:
 491         kfree_skb(skb);
 492  out:
 493         return ret;
 494 }
 495
 496 static ssize_t ppp_write(struct file *file, const char __user *buf,
 497                          size_t count, loff_t *ppos)
 498 {
 499         struct ppp_file *pf = file->private_data;
 500         struct sk_buff *skb;
 501         ssize_t ret;
 502
 503         if (!pf)
 504                 return -ENXIO;
 505         ret = -ENOMEM;
 506         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 507         if (!skb)
 508                 goto out;
 509         skb_reserve(skb, pf->hdrlen);
 510         ret = -EFAULT;
 511         if (copy_from_user(skb_put(skb, count), buf, count)) {
 512                 kfree_skb(skb);
 513                 goto out;
 514         }
 515
 516         switch (pf->kind) {
 517         case INTERFACE:
 518                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 519                 break;
 520         case CHANNEL:
 521                 skb_queue_tail(&pf->xq, skb);
 522                 ppp_channel_push(PF_TO_CHANNEL(pf));
 523                 break;
 524         }
 525
 526         ret = count;
 527
 528  out:
 529         return ret;
 530 }
 531
 532 /* No kernel lock - fine */
 533 static __poll_t ppp_poll(struct file *file, poll_table *wait)
 534 {
 535         struct ppp_file *pf = file->private_data;
 536         __poll_t mask;
 537
 538         if (!pf)
 539                 return 0;
 540         poll_wait(file, &pf->rwait, wait);
 541         mask = EPOLLOUT | EPOLLWRNORM;
 542         if (skb_peek(&pf->rq))
 543                 mask |= EPOLLIN | EPOLLRDNORM;
 544         if (pf->dead)
 545                 mask |= EPOLLHUP;
 546         else if (pf->kind == INTERFACE) {
 547                 /* see comment in ppp_read */
 548                 struct ppp *ppp = PF_TO_PPP(pf);
 549
 550                 ppp_recv_lock(ppp);
 551                 if (ppp->n_channels == 0 &&
 552                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 553                         mask |= EPOLLIN | EPOLLRDNORM;
 554                 ppp_recv_unlock(ppp);
 555         }
 556
 557         return mask;
 558 }
 559
 560 #ifdef CONFIG_PPP_FILTER
 561 static int get_filter(void __user *arg, struct sock_filter **p)
 562 {
 563         struct sock_fprog uprog;
 564         struct sock_filter *code = NULL;
 565         int len;
 566
 567         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 568                 return -EFAULT;
 569
 570         if (!uprog.len) {
 571                 *p = NULL;
 572                 return 0;
 573         }
 574
 575         len = uprog.len * sizeof(struct sock_filter);
 576         code = memdup_user(uprog.filter, len);
 577         if (IS_ERR(code))
 578                 return PTR_ERR(code);
 579
 580         *p = code;
 581         return uprog.len;
 582 }
 583 #endif /* CONFIG_PPP_FILTER */
 584
 585 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 586 {
 587         struct ppp_file *pf;
 588         struct ppp *ppp;
 589         int err = -EFAULT, val, val2, i;
 590         struct ppp_idle idle;
 591         struct npioctl npi;
 592         int unit, cflags;
 593         struct slcompress *vj;
 594         void __user *argp = (void __user *)arg;
 595         int __user *p = argp;
 596
 597         mutex_lock(&ppp_mutex);
 598
 599         pf = file->private_data;
 600         if (!pf) {
 601                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 602                                            pf, file, cmd, arg);
 603                 goto out;
 604         }
 605
 606         if (cmd == PPPIOCDETACH) {
 607                 /*
 608                  * PPPIOCDETACH is no longer supported as it was heavily broken,
 609                  * and is only known to have been used by pppd older than
 610                  * ppp-2.4.2 (released November 2003).
 611                  */
 612                 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
 613                              current->comm, current->pid);
 614                 err = -EINVAL;
 615                 goto out;
 616         }
 617
 618         if (pf->kind == CHANNEL) {
 619                 struct channel *pch;
 620                 struct ppp_channel *chan;
 621
 622                 pch = PF_TO_CHANNEL(pf);
 623
 624                 switch (cmd) {
 625                 case PPPIOCCONNECT:
 626                         if (get_user(unit, p))
 627                                 break;
 628                         err = ppp_connect_channel(pch, unit);
 629                         break;
 630
 631                 case PPPIOCDISCONN:
 632                         err = ppp_disconnect_channel(pch);
 633                         break;
 634
 635                 default:
 636                         down_read(&pch->chan_sem);
 637                         chan = pch->chan;
 638                         err = -ENOTTY;
 639                         if (chan && chan->ops->ioctl)
 640                                 err = chan->ops->ioctl(chan, cmd, arg);
 641                         up_read(&pch->chan_sem);
 642                 }
 643                 goto out;
 644         }
 645
 646         if (pf->kind != INTERFACE) {
 647                 /* can't happen */
 648                 pr_err("PPP: not interface or channel??\n");
 649                 err = -EINVAL;
 650                 goto out;
 651         }
 652
 653         ppp = PF_TO_PPP(pf);
 654         switch (cmd) {
 655         case PPPIOCSMRU:
 656                 if (get_user(val, p))
 657                         break;
 658                 ppp->mru = val;
 659                 err = 0;
 660                 break;
 661
 662         case PPPIOCSFLAGS:
 663                 if (get_user(val, p))
 664                         break;
 665                 ppp_lock(ppp);
 666                 cflags = ppp->flags & ~val;
 667 #ifdef CONFIG_PPP_MULTILINK
 668                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 669                         ppp->nextseq = 0;
 670 #endif
 671                 ppp->flags = val & SC_FLAG_BITS;
 672                 ppp_unlock(ppp);
 673                 if (cflags & SC_CCP_OPEN)
 674                         ppp_ccp_closed(ppp);
 675                 err = 0;
 676                 break;
 677
 678         case PPPIOCGFLAGS:
 679                 val = ppp->flags | ppp->xstate | ppp->rstate;
 680                 if (put_user(val, p))
 681                         break;
 682                 err = 0;
 683                 break;
 684
 685         case PPPIOCSCOMPRESS:
 686                 err = ppp_set_compress(ppp, arg);
 687                 break;
 688
 689         case PPPIOCGUNIT:
 690                 if (put_user(ppp->file.index, p))
 691                         break;
 692                 err = 0;
 693                 break;
 694
 695         case PPPIOCSDEBUG:
 696                 if (get_user(val, p))
 697                         break;
 698                 ppp->debug = val;
 699                 err = 0;
 700                 break;
 701
 702         case PPPIOCGDEBUG:
 703                 if (put_user(ppp->debug, p))
 704                         break;
 705                 err = 0;
 706                 break;
 707
 708         case PPPIOCGIDLE:
 709                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 710                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 711                 if (copy_to_user(argp, &idle, sizeof(idle)))
 712                         break;
 713                 err = 0;
 714                 break;
 715
 716         case PPPIOCSMAXCID:
 717                 if (get_user(val, p))
 718                         break;
 719                 val2 = 15;
 720                 if ((val >> 16) != 0) {
 721                         val2 = val >> 16;
 722                         val &= 0xffff;
 723                 }
 724                 vj = slhc_init(val2+1, val+1);
 725                 if (IS_ERR(vj)) {
 726                         err = PTR_ERR(vj);
 727                         break;
 728                 }
 729                 ppp_lock(ppp);
 730                 if (ppp->vj)
 731                         slhc_free(ppp->vj);
 732                 ppp->vj = vj;
 733                 ppp_unlock(ppp);
 734                 err = 0;
 735                 break;
 736
 737         case PPPIOCGNPMODE:
 738         case PPPIOCSNPMODE:
 739                 if (copy_from_user(&npi, argp, sizeof(npi)))
 740                         break;
 741                 err = proto_to_npindex(npi.protocol);
 742                 if (err < 0)
 743                         break;
 744                 i = err;
 745                 if (cmd == PPPIOCGNPMODE) {
 746                         err = -EFAULT;
 747                         npi.mode = ppp->npmode[i];
 748                         if (copy_to_user(argp, &npi, sizeof(npi)))
 749                                 break;
 750                 } else {
 751                         ppp->npmode[i] = npi.mode;
 752                         /* we may be able to transmit more packets now (??) */
 753                         netif_wake_queue(ppp->dev);
 754                 }
 755                 err = 0;
 756                 break;
 757
 758 #ifdef CONFIG_PPP_FILTER
 759         case PPPIOCSPASS:
 760         {
 761                 struct sock_filter *code;
 762
 763                 err = get_filter(argp, &code);
 764                 if (err >= 0) {
 765                         struct bpf_prog *pass_filter = NULL;
 766                         struct sock_fprog_kern fprog = {
 767                                 .len = err,
 768                                 .filter = code,
 769                         };
 770
 771                         err = 0;
 772                         if (fprog.filter)
 773                                 err = bpf_prog_create(&pass_filter, &fprog);
 774                         if (!err) {
 775                                 ppp_lock(ppp);
 776                                 if (ppp->pass_filter)
 777                                         bpf_prog_destroy(ppp->pass_filter);
 778                                 ppp->pass_filter = pass_filter;
 779                                 ppp_unlock(ppp);
 780                         }
 781                         kfree(code);
 782                 }
 783                 break;
 784         }
 785         case PPPIOCSACTIVE:
 786         {
 787                 struct sock_filter *code;
 788
 789                 err = get_filter(argp, &code);
 790                 if (err >= 0) {
 791                         struct bpf_prog *active_filter = NULL;
 792                         struct sock_fprog_kern fprog = {
 793                                 .len = err,
 794                                 .filter = code,
 795                         };
 796
 797                         err = 0;
 798                         if (fprog.filter)
 799                                 err = bpf_prog_create(&active_filter, &fprog);
 800                         if (!err) {
 801                                 ppp_lock(ppp);
 802                                 if (ppp->active_filter)
 803                                         bpf_prog_destroy(ppp->active_filter);
 804                                 ppp->active_filter = active_filter;
 805                                 ppp_unlock(ppp);
 806                         }
 807                         kfree(code);
 808                 }
 809                 break;
 810         }
 811 #endif /* CONFIG_PPP_FILTER */
 812
 813 #ifdef CONFIG_PPP_MULTILINK
 814         case PPPIOCSMRRU:
 815                 if (get_user(val, p))
 816                         break;
 817                 ppp_recv_lock(ppp);
 818                 ppp->mrru = val;
 819                 ppp_recv_unlock(ppp);
 820                 err = 0;
 821                 break;
 822 #endif /* CONFIG_PPP_MULTILINK */
 823
 824         default:
 825                 err = -ENOTTY;
 826         }
 827
 828 out:
 829         mutex_unlock(&ppp_mutex);
 830
 831         return err;
 832 }
 833
 834 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 835                         struct file *file, unsigned int cmd, unsigned long arg)
 836 {
 837         int unit, err = -EFAULT;
 838         struct ppp *ppp;
 839         struct channel *chan;
 840         struct ppp_net *pn;
 841         int __user *p = (int __user *)arg;
 842
 843         switch (cmd) {
 844         case PPPIOCNEWUNIT:
 845                 /* Create a new ppp unit */
 846                 if (get_user(unit, p))
 847                         break;
 848                 err = ppp_create_interface(net, file, &unit);
 849                 if (err < 0)
 850                         break;
 851
 852                 err = -EFAULT;
 853                 if (put_user(unit, p))
 854                         break;
 855                 err = 0;
 856                 break;
 857
 858         case PPPIOCATTACH:
 859                 /* Attach to an existing ppp unit */
 860                 if (get_user(unit, p))
 861                         break;
 862                 err = -ENXIO;
 863                 pn = ppp_pernet(net);
 864                 mutex_lock(&pn->all_ppp_mutex);
 865                 ppp = ppp_find_unit(pn, unit);
 866                 if (ppp) {
 867                         refcount_inc(&ppp->file.refcnt);
 868                         file->private_data = &ppp->file;
 869                         err = 0;
 870                 }
 871                 mutex_unlock(&pn->all_ppp_mutex);
 872                 break;
 873
 874         case PPPIOCATTCHAN:
 875                 if (get_user(unit, p))
 876                         break;
 877                 err = -ENXIO;
 878                 pn = ppp_pernet(net);
 879                 spin_lock_bh(&pn->all_channels_lock);
 880                 chan = ppp_find_channel(pn, unit);
 881                 if (chan) {
 882                         refcount_inc(&chan->file.refcnt);
 883                         file->private_data = &chan->file;
 884                         err = 0;
 885                 }
 886                 spin_unlock_bh(&pn->all_channels_lock);
 887                 break;
 888
 889         default:
 890                 err = -ENOTTY;
 891         }
 892
 893         return err;
 894 }
 895
 896 static const struct file_operations ppp_device_fops = {
 897         .owner          = THIS_MODULE,
 898         .read           = ppp_read,
 899         .write          = ppp_write,
 900         .poll           = ppp_poll,
 901         .unlocked_ioctl = ppp_ioctl,
 902         .open           = ppp_open,
 903         .release        = ppp_release,
 904         .llseek         = noop_llseek,
 905 };
 906
 907 static __net_init int ppp_init_net(struct net *net)
 908 {
 909         struct ppp_net *pn = net_generic(net, ppp_net_id);
 910
 911         idr_init(&pn->units_idr);
 912         mutex_init(&pn->all_ppp_mutex);
 913
 914         INIT_LIST_HEAD(&pn->all_channels);
 915         INIT_LIST_HEAD(&pn->new_channels);
 916
 917         spin_lock_init(&pn->all_channels_lock);
 918
 919         return 0;
 920 }
 921
 922 static __net_exit void ppp_exit_net(struct net *net)
 923 {
 924         struct ppp_net *pn = net_generic(net, ppp_net_id);
 925         struct net_device *dev;
 926         struct net_device *aux;
 927         struct ppp *ppp;
 928         LIST_HEAD(list);
 929         int id;
 930
 931         rtnl_lock();
 932         for_each_netdev_safe(net, dev, aux) {
 933                 if (dev->netdev_ops == &ppp_netdev_ops)
 934                         unregister_netdevice_queue(dev, &list);
 935         }
 936
 937         idr_for_each_entry(&pn->units_idr, ppp, id)
 938                 /* Skip devices already unregistered by previous loop */
 939                 if (!net_eq(dev_net(ppp->dev), net))
 940                         unregister_netdevice_queue(ppp->dev, &list);
 941
 942         unregister_netdevice_many(&list);
 943         rtnl_unlock();
 944
 945         mutex_destroy(&pn->all_ppp_mutex);
 946         idr_destroy(&pn->units_idr);
 947         WARN_ON_ONCE(!list_empty(&pn->all_channels));
 948         WARN_ON_ONCE(!list_empty(&pn->new_channels));
 949 }
 950
 951 static struct pernet_operations ppp_net_ops = {
 952         .init = ppp_init_net,
 953         .exit = ppp_exit_net,
 954         .id   = &ppp_net_id,
 955         .size = sizeof(struct ppp_net),
 956 };
 957
 958 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
 959 {
 960         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
 961         int ret;
 962
 963         mutex_lock(&pn->all_ppp_mutex);
 964
 965         if (unit < 0) {
 966                 ret = unit_get(&pn->units_idr, ppp, 0);
 967                 if (ret < 0)
 968                         goto err;
 969                 if (!ifname_is_set) {
 970                         while (1) {
 971                                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
 972                                 if (!__dev_get_by_name(ppp->ppp_net, ppp->dev->name))
 973                                         break;
 974                                 unit_put(&pn->units_idr, ret);
 975                                 ret = unit_get(&pn->units_idr, ppp, ret + 1);
 976                                 if (ret < 0)
 977                                         goto err;
 978                         }
 979                 }
 980         } else {
 981                 /* Caller asked for a specific unit number. Fail with -EEXIST
 982                  * if unavailable. For backward compatibility, return -EEXIST
 983                  * too if idr allocation fails; this makes pppd retry without
 984                  * requesting a specific unit number.
 985                  */
 986                 if (unit_find(&pn->units_idr, unit)) {
 987                         ret = -EEXIST;
 988                         goto err;
 989                 }
 990                 ret = unit_set(&pn->units_idr, ppp, unit);
 991                 if (ret < 0) {
 992                         /* Rewrite error for backward compatibility */
 993                         ret = -EEXIST;
 994                         goto err;
 995                 }
 996         }
 997         ppp->file.index = ret;
 998
 999         if (!ifname_is_set)
1000                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1001
1002         mutex_unlock(&pn->all_ppp_mutex);
1003
1004         ret = register_netdevice(ppp->dev);
1005         if (ret < 0)
1006                 goto err_unit;
1007
1008         atomic_inc(&ppp_unit_count);
1009
1010         return 0;
1011
1012 err_unit:
1013         mutex_lock(&pn->all_ppp_mutex);
1014         unit_put(&pn->units_idr, ppp->file.index);
1015 err:
1016         mutex_unlock(&pn->all_ppp_mutex);
1017
1018         return ret;
1019 }
1020
1021 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1022                              const struct ppp_config *conf)
1023 {
1024         struct ppp *ppp = netdev_priv(dev);
1025         int indx;
1026         int err;
1027         int cpu;
1028
1029         ppp->dev = dev;
1030         ppp->ppp_net = src_net;
1031         ppp->mru = PPP_MRU;
1032         ppp->owner = conf->file;
1033
1034         init_ppp_file(&ppp->file, INTERFACE);
1035         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1036
1037         for (indx = 0; indx < NUM_NP; ++indx)
1038                 ppp->npmode[indx] = NPMODE_PASS;
1039         INIT_LIST_HEAD(&ppp->channels);
1040         spin_lock_init(&ppp->rlock);
1041         spin_lock_init(&ppp->wlock);
1042
1043         ppp->xmit_recursion = alloc_percpu(int);
1044         if (!ppp->xmit_recursion) {
1045                 err = -ENOMEM;
1046                 goto err1;
1047         }
1048         for_each_possible_cpu(cpu)
1049                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1050
1051 #ifdef CONFIG_PPP_MULTILINK
1052         ppp->minseq = -1;
1053         skb_queue_head_init(&ppp->mrq);
1054 #endif /* CONFIG_PPP_MULTILINK */
1055 #ifdef CONFIG_PPP_FILTER
1056         ppp->pass_filter = NULL;
1057         ppp->active_filter = NULL;
1058 #endif /* CONFIG_PPP_FILTER */
1059
1060         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1061         if (err < 0)
1062                 goto err2;
1063
1064         conf->file->private_data = &ppp->file;
1065
1066         return 0;
1067 err2:
1068         free_percpu(ppp->xmit_recursion);
1069 err1:
1070         return err;
1071 }
1072
1073 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1074         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1075 };
1076
1077 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1078                            struct netlink_ext_ack *extack)
1079 {
1080         if (!data)
1081                 return -EINVAL;
1082
1083         if (!data[IFLA_PPP_DEV_FD])
1084                 return -EINVAL;
1085         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1086                 return -EBADF;
1087
1088         return 0;
1089 }
1090
1091 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1092                           struct nlattr *tb[], struct nlattr *data[],
1093                           struct netlink_ext_ack *extack)
1094 {
1095         struct ppp_config conf = {
1096                 .unit = -1,
1097                 .ifname_is_set = true,
1098         };
1099         struct file *file;
1100         int err;
1101
1102         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1103         if (!file)
1104                 return -EBADF;
1105
1106         /* rtnl_lock is already held here, but ppp_create_interface() locks
1107          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1108          * possible deadlock due to lock order inversion, at the cost of
1109          * pushing the problem back to userspace.
1110          */
1111         if (!mutex_trylock(&ppp_mutex)) {
1112                 err = -EBUSY;
1113                 goto out;
1114         }
1115
1116         if (file->f_op != &ppp_device_fops || file->private_data) {
1117                 err = -EBADF;
1118                 goto out_unlock;
1119         }
1120
1121         conf.file = file;
1122
1123         /* Don't use device name generated by the rtnetlink layer when ifname
1124          * isn't specified. Let ppp_dev_configure() set the device name using
1125          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1126          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1127          */
1128         if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1129                 conf.ifname_is_set = false;
1130
1131         err = ppp_dev_configure(src_net, dev, &conf);
1132
1133 out_unlock:
1134         mutex_unlock(&ppp_mutex);
1135 out:
1136         fput(file);
1137
1138         return err;
1139 }
1140
1141 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1142 {
1143         unregister_netdevice_queue(dev, head);
1144 }
1145
1146 static size_t ppp_nl_get_size(const struct net_device *dev)
1147 {
1148         return 0;
1149 }
1150
1151 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1152 {
1153         return 0;
1154 }
1155
1156 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1157 {
1158         struct ppp *ppp = netdev_priv(dev);
1159
1160         return ppp->ppp_net;
1161 }
1162
1163 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1164         .kind           = "ppp",
1165         .maxtype        = IFLA_PPP_MAX,
1166         .policy         = ppp_nl_policy,
1167         .priv_size      = sizeof(struct ppp),
1168         .setup          = ppp_setup,
1169         .validate       = ppp_nl_validate,
1170         .newlink        = ppp_nl_newlink,
1171         .dellink        = ppp_nl_dellink,
1172         .get_size       = ppp_nl_get_size,
1173         .fill_info      = ppp_nl_fill_info,
1174         .get_link_net   = ppp_nl_get_link_net,
1175 };
1176
1177 #define PPP_MAJOR       108
1178
1179 /* Called at boot time if ppp is compiled into the kernel,
1180    or at module load time (from init_module) if compiled as a module. */
1181 static int __init ppp_init(void)
1182 {
1183         int err;
1184
1185         pr_info("PPP generic driver version " PPP_VERSION "\n");
1186
1187         err = register_pernet_device(&ppp_net_ops);
1188         if (err) {
1189                 pr_err("failed to register PPP pernet device (%d)\n", err);
1190                 goto out;
1191         }
1192
1193         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1194         if (err) {
1195                 pr_err("failed to register PPP device (%d)\n", err);
1196                 goto out_net;
1197         }
1198
1199         ppp_class = class_create(THIS_MODULE, "ppp");
1200         if (IS_ERR(ppp_class)) {
1201                 err = PTR_ERR(ppp_class);
1202                 goto out_chrdev;
1203         }
1204
1205         err = rtnl_link_register(&ppp_link_ops);
1206         if (err) {
1207                 pr_err("failed to register rtnetlink PPP handler\n");
1208                 goto out_class;
1209         }
1210
1211         /* not a big deal if we fail here :-) */
1212         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1213
1214         return 0;
1215
1216 out_class:
1217         class_destroy(ppp_class);
1218 out_chrdev:
1219         unregister_chrdev(PPP_MAJOR, "ppp");
1220 out_net:
1221         unregister_pernet_device(&ppp_net_ops);
1222 out:
1223         return err;
1224 }
1225
1226 /*
1227  * Network interface unit routines.
1228  */
1229 static netdev_tx_t
1230 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1231 {
1232         struct ppp *ppp = netdev_priv(dev);
1233         int npi, proto;
1234         unsigned char *pp;
1235
1236         npi = ethertype_to_npindex(ntohs(skb->protocol));
1237         if (npi < 0)
1238                 goto outf;
1239
1240         /* Drop, accept or reject the packet */
1241         switch (ppp->npmode[npi]) {
1242         case NPMODE_PASS:
1243                 break;
1244         case NPMODE_QUEUE:
1245                 /* it would be nice to have a way to tell the network
1246                    system to queue this one up for later. */
1247                 goto outf;
1248         case NPMODE_DROP:
1249         case NPMODE_ERROR:
1250                 goto outf;
1251         }
1252
1253         /* Put the 2-byte PPP protocol number on the front,
1254            making sure there is room for the address and control fields. */
1255         if (skb_cow_head(skb, PPP_HDRLEN))
1256                 goto outf;
1257
1258         pp = skb_push(skb, 2);
1259         proto = npindex_to_proto[npi];
1260         put_unaligned_be16(proto, pp);
1261
1262         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1263         ppp_xmit_process(ppp, skb);
1264
1265         return NETDEV_TX_OK;
1266
1267  outf:
1268         kfree_skb(skb);
1269         ++dev->stats.tx_dropped;
1270         return NETDEV_TX_OK;
1271 }
1272
1273 static int
1274 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1275 {
1276         struct ppp *ppp = netdev_priv(dev);
1277         int err = -EFAULT;
1278         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1279         struct ppp_stats stats;
1280         struct ppp_comp_stats cstats;
1281         char *vers;
1282
1283         switch (cmd) {
1284         case SIOCGPPPSTATS:
1285                 ppp_get_stats(ppp, &stats);
1286                 if (copy_to_user(addr, &stats, sizeof(stats)))
1287                         break;
1288                 err = 0;
1289                 break;
1290
1291         case SIOCGPPPCSTATS:
1292                 memset(&cstats, 0, sizeof(cstats));
1293                 if (ppp->xc_state)
1294                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1295                 if (ppp->rc_state)
1296                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1297                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1298                         break;
1299                 err = 0;
1300                 break;
1301
1302         case SIOCGPPPVER:
1303                 vers = PPP_VERSION;
1304                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1305                         break;
1306                 err = 0;
1307                 break;
1308
1309         default:
1310                 err = -EINVAL;
1311         }
1312
1313         return err;
1314 }
1315
1316 static void
1317 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1318 {
1319         struct ppp *ppp = netdev_priv(dev);
1320
1321         ppp_recv_lock(ppp);
1322         stats64->rx_packets = ppp->stats64.rx_packets;
1323         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1324         ppp_recv_unlock(ppp);
1325
1326         ppp_xmit_lock(ppp);
1327         stats64->tx_packets = ppp->stats64.tx_packets;
1328         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1329         ppp_xmit_unlock(ppp);
1330
1331         stats64->rx_errors        = dev->stats.rx_errors;
1332         stats64->tx_errors        = dev->stats.tx_errors;
1333         stats64->rx_dropped       = dev->stats.rx_dropped;
1334         stats64->tx_dropped       = dev->stats.tx_dropped;
1335         stats64->rx_length_errors = dev->stats.rx_length_errors;
1336 }
1337
1338 static int ppp_dev_init(struct net_device *dev)
1339 {
1340         struct ppp *ppp;
1341
1342         netdev_lockdep_set_classes(dev);
1343
1344         ppp = netdev_priv(dev);
1345         /* Let the netdevice take a reference on the ppp file. This ensures
1346          * that ppp_destroy_interface() won't run before the device gets
1347          * unregistered.
1348          */
1349         refcount_inc(&ppp->file.refcnt);
1350
1351         return 0;
1352 }
1353
1354 static void ppp_dev_uninit(struct net_device *dev)
1355 {
1356         struct ppp *ppp = netdev_priv(dev);
1357         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1358
1359         ppp_lock(ppp);
1360         ppp->closing = 1;
1361         ppp_unlock(ppp);
1362
1363         mutex_lock(&pn->all_ppp_mutex);
1364         unit_put(&pn->units_idr, ppp->file.index);
1365         mutex_unlock(&pn->all_ppp_mutex);
1366
1367         ppp->owner = NULL;
1368
1369         ppp->file.dead = 1;
1370         wake_up_interruptible(&ppp->file.rwait);
1371 }
1372
1373 static void ppp_dev_priv_destructor(struct net_device *dev)
1374 {
1375         struct ppp *ppp;
1376
1377         ppp = netdev_priv(dev);
1378         if (refcount_dec_and_test(&ppp->file.refcnt))
1379                 ppp_destroy_interface(ppp);
1380 }
1381
1382 static const struct net_device_ops ppp_netdev_ops = {
1383         .ndo_init        = ppp_dev_init,
1384         .ndo_uninit      = ppp_dev_uninit,
1385         .ndo_start_xmit  = ppp_start_xmit,
1386         .ndo_do_ioctl    = ppp_net_ioctl,
1387         .ndo_get_stats64 = ppp_get_stats64,
1388 };
1389
1390 static struct device_type ppp_type = {
1391         .name = "ppp",
1392 };
1393
1394 static void ppp_setup(struct net_device *dev)
1395 {
1396         dev->netdev_ops = &ppp_netdev_ops;
1397         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1398
1399         dev->features |= NETIF_F_LLTX;
1400
1401         dev->hard_header_len = PPP_HDRLEN;
1402         dev->mtu = PPP_MRU;
1403         dev->addr_len = 0;
1404         dev->tx_queue_len = 3;
1405         dev->type = ARPHRD_PPP;
1406         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1407         dev->priv_destructor = ppp_dev_priv_destructor;
1408         netif_keep_dst(dev);
1409 }
1410
1411 /*
1412  * Transmit-side routines.
1413  */
1414
1415 /* Called to do any work queued up on the transmit side that can now be done */
1416 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1417 {
1418         ppp_xmit_lock(ppp);
1419         if (!ppp->closing) {
1420                 ppp_push(ppp);
1421
1422                 if (skb)
1423                         skb_queue_tail(&ppp->file.xq, skb);
1424                 while (!ppp->xmit_pending &&
1425                        (skb = skb_dequeue(&ppp->file.xq)))
1426                         ppp_send_frame(ppp, skb);
1427                 /* If there's no work left to do, tell the core net
1428                    code that we can accept some more. */
1429                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1430                         netif_wake_queue(ppp->dev);
1431                 else
1432                         netif_stop_queue(ppp->dev);
1433         } else {
1434                 kfree_skb(skb);
1435         }
1436         ppp_xmit_unlock(ppp);
1437 }
1438
1439 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1440 {
1441         local_bh_disable();
1442
1443         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1444                 goto err;
1445
1446         (*this_cpu_ptr(ppp->xmit_recursion))++;
1447         __ppp_xmit_process(ppp, skb);
1448         (*this_cpu_ptr(ppp->xmit_recursion))--;
1449
1450         local_bh_enable();
1451
1452         return;
1453
1454 err:
1455         local_bh_enable();
1456
1457         kfree_skb(skb);
1458
1459         if (net_ratelimit())
1460                 netdev_err(ppp->dev, "recursion detected\n");
1461 }
1462
1463 static inline struct sk_buff *
1464 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1465 {
1466         struct sk_buff *new_skb;
1467         int len;
1468         int new_skb_size = ppp->dev->mtu +
1469                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1470         int compressor_skb_size = ppp->dev->mtu +
1471                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1472         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1473         if (!new_skb) {
1474                 if (net_ratelimit())
1475                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1476                 return NULL;
1477         }
1478         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1479                 skb_reserve(new_skb,
1480                             ppp->dev->hard_header_len - PPP_HDRLEN);
1481
1482         /* compressor still expects A/C bytes in hdr */
1483         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1484                                    new_skb->data, skb->len + 2,
1485                                    compressor_skb_size);
1486         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1487                 consume_skb(skb);
1488                 skb = new_skb;
1489                 skb_put(skb, len);
1490                 skb_pull(skb, 2);       /* pull off A/C bytes */
1491         } else if (len == 0) {
1492                 /* didn't compress, or CCP not up yet */
1493                 consume_skb(new_skb);
1494                 new_skb = skb;
1495         } else {
1496                 /*
1497                  * (len < 0)
1498                  * MPPE requires that we do not send unencrypted
1499                  * frames.  The compressor will return -1 if we
1500                  * should drop the frame.  We cannot simply test
1501                  * the compress_proto because MPPE and MPPC share
1502                  * the same number.
1503                  */
1504                 if (net_ratelimit())
1505                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1506                 kfree_skb(skb);
1507                 consume_skb(new_skb);
1508                 new_skb = NULL;
1509         }
1510         return new_skb;
1511 }
1512
1513 /*
1514  * Compress and send a frame.
1515  * The caller should have locked the xmit path,
1516  * and xmit_pending should be 0.
1517  */
1518 static void
1519 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1520 {
1521         int proto = PPP_PROTO(skb);
1522         struct sk_buff *new_skb;
1523         int len;
1524         unsigned char *cp;
1525
1526         if (proto < 0x8000) {
1527 #ifdef CONFIG_PPP_FILTER
1528                 /* check if we should pass this packet */
1529                 /* the filter instructions are constructed assuming
1530                    a four-byte PPP header on each packet */
1531                 *(u8 *)skb_push(skb, 2) = 1;
1532                 if (ppp->pass_filter &&
1533                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1534                         if (ppp->debug & 1)
1535                                 netdev_printk(KERN_DEBUG, ppp->dev,
1536                                               "PPP: outbound frame "
1537                                               "not passed\n");
1538                         kfree_skb(skb);
1539                         return;
1540                 }
1541                 /* if this packet passes the active filter, record the time */
1542                 if (!(ppp->active_filter &&
1543                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1544                         ppp->last_xmit = jiffies;
1545                 skb_pull(skb, 2);
1546 #else
1547                 /* for data packets, record the time */
1548                 ppp->last_xmit = jiffies;
1549 #endif /* CONFIG_PPP_FILTER */
1550         }
1551
1552         ++ppp->stats64.tx_packets;
1553         ppp->stats64.tx_bytes += skb->len - 2;
1554
1555         switch (proto) {
1556         case PPP_IP:
1557                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1558                         break;
1559                 /* try to do VJ TCP header compression */
1560                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1561                                     GFP_ATOMIC);
1562                 if (!new_skb) {
1563                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1564                         goto drop;
1565                 }
1566                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1567                 cp = skb->data + 2;
1568                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1569                                     new_skb->data + 2, &cp,
1570                                     !(ppp->flags & SC_NO_TCP_CCID));
1571                 if (cp == skb->data + 2) {
1572                         /* didn't compress */
1573                         consume_skb(new_skb);
1574                 } else {
1575                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1576                                 proto = PPP_VJC_COMP;
1577                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1578                         } else {
1579                                 proto = PPP_VJC_UNCOMP;
1580                                 cp[0] = skb->data[2];
1581                         }
1582                         consume_skb(skb);
1583                         skb = new_skb;
1584                         cp = skb_put(skb, len + 2);
1585                         cp[0] = 0;
1586                         cp[1] = proto;
1587                 }
1588                 break;
1589
1590         case PPP_CCP:
1591                 /* peek at outbound CCP frames */
1592                 ppp_ccp_peek(ppp, skb, 0);
1593                 break;
1594         }
1595
1596         /* try to do packet compression */
1597         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1598             proto != PPP_LCP && proto != PPP_CCP) {
1599                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1600                         if (net_ratelimit())
1601                                 netdev_err(ppp->dev,
1602                                            "ppp: compression required but "
1603                                            "down - pkt dropped.\n");
1604                         goto drop;
1605                 }
1606                 skb = pad_compress_skb(ppp, skb);
1607                 if (!skb)
1608                         goto drop;
1609         }
1610
1611         /*
1612          * If we are waiting for traffic (demand dialling),
1613          * queue it up for pppd to receive.
1614          */
1615         if (ppp->flags & SC_LOOP_TRAFFIC) {
1616                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1617                         goto drop;
1618                 skb_queue_tail(&ppp->file.rq, skb);
1619                 wake_up_interruptible(&ppp->file.rwait);
1620                 return;
1621         }
1622
1623         ppp->xmit_pending = skb;
1624         ppp_push(ppp);
1625         return;
1626
1627  drop:
1628         kfree_skb(skb);
1629         ++ppp->dev->stats.tx_errors;
1630 }
1631
1632 /*
1633  * Try to send the frame in xmit_pending.
1634  * The caller should have the xmit path locked.
1635  */
1636 static void
1637 ppp_push(struct ppp *ppp)
1638 {
1639         struct list_head *list;
1640         struct channel *pch;
1641         struct sk_buff *skb = ppp->xmit_pending;
1642
1643         if (!skb)
1644                 return;
1645
1646         list = &ppp->channels;
1647         if (list_empty(list)) {
1648                 /* nowhere to send the packet, just drop it */
1649                 ppp->xmit_pending = NULL;
1650                 kfree_skb(skb);
1651                 return;
1652         }
1653
1654         if ((ppp->flags & SC_MULTILINK) == 0) {
1655                 /* not doing multilink: send it down the first channel */
1656                 list = list->next;
1657                 pch = list_entry(list, struct channel, clist);
1658
1659                 spin_lock(&pch->downl);
1660                 if (pch->chan) {
1661                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1662                                 ppp->xmit_pending = NULL;
1663                 } else {
1664                         /* channel got unregistered */
1665                         kfree_skb(skb);
1666                         ppp->xmit_pending = NULL;
1667                 }
1668                 spin_unlock(&pch->downl);
1669                 return;
1670         }
1671
1672 #ifdef CONFIG_PPP_MULTILINK
1673         /* Multilink: fragment the packet over as many links
1674            as can take the packet at the moment. */
1675         if (!ppp_mp_explode(ppp, skb))
1676                 return;
1677 #endif /* CONFIG_PPP_MULTILINK */
1678
1679         ppp->xmit_pending = NULL;
1680         kfree_skb(skb);
1681 }
1682
1683 #ifdef CONFIG_PPP_MULTILINK
1684 static bool mp_protocol_compress __read_mostly = true;
1685 module_param(mp_protocol_compress, bool, 0644);
1686 MODULE_PARM_DESC(mp_protocol_compress,
1687                  "compress protocol id in multilink fragments");
1688
1689 /*
1690  * Divide a packet to be transmitted into fragments and
1691  * send them out the individual links.
1692  */
1693 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1694 {
1695         int len, totlen;
1696         int i, bits, hdrlen, mtu;
1697         int flen;
1698         int navail, nfree, nzero;
1699         int nbigger;
1700         int totspeed;
1701         int totfree;
1702         unsigned char *p, *q;
1703         struct list_head *list;
1704         struct channel *pch;
1705         struct sk_buff *frag;
1706         struct ppp_channel *chan;
1707
1708         totspeed = 0; /*total bitrate of the bundle*/
1709         nfree = 0; /* # channels which have no packet already queued */
1710         navail = 0; /* total # of usable channels (not deregistered) */
1711         nzero = 0; /* number of channels with zero speed associated*/
1712         totfree = 0; /*total # of channels available and
1713                                   *having no queued packets before
1714                                   *starting the fragmentation*/
1715
1716         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1717         i = 0;
1718         list_for_each_entry(pch, &ppp->channels, clist) {
1719                 if (pch->chan) {
1720                         pch->avail = 1;
1721                         navail++;
1722                         pch->speed = pch->chan->speed;
1723                 } else {
1724                         pch->avail = 0;
1725                 }
1726                 if (pch->avail) {
1727                         if (skb_queue_empty(&pch->file.xq) ||
1728                                 !pch->had_frag) {
1729                                         if (pch->speed == 0)
1730                                                 nzero++;
1731                                         else
1732                                                 totspeed += pch->speed;
1733
1734                                         pch->avail = 2;
1735                                         ++nfree;
1736                                         ++totfree;
1737                                 }
1738                         if (!pch->had_frag && i < ppp->nxchan)
1739                                 ppp->nxchan = i;
1740                 }
1741                 ++i;
1742         }
1743         /*
1744          * Don't start sending this packet unless at least half of
1745          * the channels are free.  This gives much better TCP
1746          * performance if we have a lot of channels.
1747          */
1748         if (nfree == 0 || nfree < navail / 2)
1749                 return 0; /* can't take now, leave it in xmit_pending */
1750
1751         /* Do protocol field compression */
1752         p = skb->data;
1753         len = skb->len;
1754         if (*p == 0 && mp_protocol_compress) {
1755                 ++p;
1756                 --len;
1757         }
1758
1759         totlen = len;
1760         nbigger = len % nfree;
1761
1762         /* skip to the channel after the one we last used
1763            and start at that one */
1764         list = &ppp->channels;
1765         for (i = 0; i < ppp->nxchan; ++i) {
1766                 list = list->next;
1767                 if (list == &ppp->channels) {
1768                         i = 0;
1769                         break;
1770                 }
1771         }
1772
1773         /* create a fragment for each channel */
1774         bits = B;
1775         while (len > 0) {
1776                 list = list->next;
1777                 if (list == &ppp->channels) {
1778                         i = 0;
1779                         continue;
1780                 }
1781                 pch = list_entry(list, struct channel, clist);
1782                 ++i;
1783                 if (!pch->avail)
1784                         continue;
1785
1786                 /*
1787                  * Skip this channel if it has a fragment pending already and
1788                  * we haven't given a fragment to all of the free channels.
1789                  */
1790                 if (pch->avail == 1) {
1791                         if (nfree > 0)
1792                                 continue;
1793                 } else {
1794                         pch->avail = 1;
1795                 }
1796
1797                 /* check the channel's mtu and whether it is still attached. */
1798                 spin_lock(&pch->downl);
1799                 if (pch->chan == NULL) {
1800                         /* can't use this channel, it's being deregistered */
1801                         if (pch->speed == 0)
1802                                 nzero--;
1803                         else
1804                                 totspeed -= pch->speed;
1805
1806                         spin_unlock(&pch->downl);
1807                         pch->avail = 0;
1808                         totlen = len;
1809                         totfree--;
1810                         nfree--;
1811                         if (--navail == 0)
1812                                 break;
1813                         continue;
1814                 }
1815
1816                 /*
1817                 *if the channel speed is not set divide
1818                 *the packet evenly among the free channels;
1819                 *otherwise divide it according to the speed
1820                 *of the channel we are going to transmit on
1821                 */
1822                 flen = len;
1823                 if (nfree > 0) {
1824                         if (pch->speed == 0) {
1825                                 flen = len/nfree;
1826                                 if (nbigger > 0) {
1827                                         flen++;
1828                                         nbigger--;
1829                                 }
1830                         } else {
1831                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1832                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1833                                 if (nbigger > 0) {
1834                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1835                                         nbigger -= ((totfree - nzero)*pch->speed)/
1836                                                         totspeed;
1837                                 }
1838                         }
1839                         nfree--;
1840                 }
1841
1842                 /*
1843                  *check if we are on the last channel or
1844                  *we exceded the length of the data to
1845                  *fragment
1846                  */
1847                 if ((nfree <= 0) || (flen > len))
1848                         flen = len;
1849                 /*
1850                  *it is not worth to tx on slow channels:
1851                  *in that case from the resulting flen according to the
1852                  *above formula will be equal or less than zero.
1853                  *Skip the channel in this case
1854                  */
1855                 if (flen <= 0) {
1856                         pch->avail = 2;
1857                         spin_unlock(&pch->downl);
1858                         continue;
1859                 }
1860
1861                 /*
1862                  * hdrlen includes the 2-byte PPP protocol field, but the
1863                  * MTU counts only the payload excluding the protocol field.
1864                  * (RFC1661 Section 2)
1865                  */
1866                 mtu = pch->chan->mtu - (hdrlen - 2);
1867                 if (mtu < 4)
1868                         mtu = 4;
1869                 if (flen > mtu)
1870                         flen = mtu;
1871                 if (flen == len)
1872                         bits |= E;
1873                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1874                 if (!frag)
1875                         goto noskb;
1876                 q = skb_put(frag, flen + hdrlen);
1877
1878                 /* make the MP header */
1879                 put_unaligned_be16(PPP_MP, q);
1880                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1881                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1882                         q[3] = ppp->nxseq;
1883                 } else {
1884                         q[2] = bits;
1885                         q[3] = ppp->nxseq >> 16;
1886                         q[4] = ppp->nxseq >> 8;
1887                         q[5] = ppp->nxseq;
1888                 }
1889
1890                 memcpy(q + hdrlen, p, flen);
1891
1892                 /* try to send it down the channel */
1893                 chan = pch->chan;
1894                 if (!skb_queue_empty(&pch->file.xq) ||
1895                         !chan->ops->start_xmit(chan, frag))
1896                         skb_queue_tail(&pch->file.xq, frag);
1897                 pch->had_frag = 1;
1898                 p += flen;
1899                 len -= flen;
1900                 ++ppp->nxseq;
1901                 bits = 0;
1902                 spin_unlock(&pch->downl);
1903         }
1904         ppp->nxchan = i;
1905
1906         return 1;
1907
1908  noskb:
1909         spin_unlock(&pch->downl);
1910         if (ppp->debug & 1)
1911                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1912         ++ppp->dev->stats.tx_errors;
1913         ++ppp->nxseq;
1914         return 1;       /* abandon the frame */
1915 }
1916 #endif /* CONFIG_PPP_MULTILINK */
1917
1918 /* Try to send data out on a channel */
1919 static void __ppp_channel_push(struct channel *pch)
1920 {
1921         struct sk_buff *skb;
1922         struct ppp *ppp;
1923
1924         spin_lock(&pch->downl);
1925         if (pch->chan) {
1926                 while (!skb_queue_empty(&pch->file.xq)) {
1927                         skb = skb_dequeue(&pch->file.xq);
1928                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1929                                 /* put the packet back and try again later */
1930                                 skb_queue_head(&pch->file.xq, skb);
1931                                 break;
1932                         }
1933                 }
1934         } else {
1935                 /* channel got deregistered */
1936                 skb_queue_purge(&pch->file.xq);
1937         }
1938         spin_unlock(&pch->downl);
1939         /* see if there is anything from the attached unit to be sent */
1940         if (skb_queue_empty(&pch->file.xq)) {
1941                 ppp = pch->ppp;
1942                 if (ppp)
1943                         __ppp_xmit_process(ppp, NULL);
1944         }
1945 }
1946
1947 static void ppp_channel_push(struct channel *pch)
1948 {
1949         read_lock_bh(&pch->upl);
1950         if (pch->ppp) {
1951                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
1952                 __ppp_channel_push(pch);
1953                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
1954         } else {
1955                 __ppp_channel_push(pch);
1956         }
1957         read_unlock_bh(&pch->upl);
1958 }
1959
1960 /*
1961  * Receive-side routines.
1962  */
1963
1964 struct ppp_mp_skb_parm {
1965         u32             sequence;
1966         u8              BEbits;
1967 };
1968 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1969
1970 static inline void
1971 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1972 {
1973         ppp_recv_lock(ppp);
1974         if (!ppp->closing)
1975                 ppp_receive_frame(ppp, skb, pch);
1976         else
1977                 kfree_skb(skb);
1978         ppp_recv_unlock(ppp);
1979 }
1980
1981 void
1982 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1983 {
1984         struct channel *pch = chan->ppp;
1985         int proto;
1986
1987         if (!pch) {
1988                 kfree_skb(skb);
1989                 return;
1990         }
1991
1992         read_lock_bh(&pch->upl);
1993         if (!pskb_may_pull(skb, 2)) {
1994                 kfree_skb(skb);
1995                 if (pch->ppp) {
1996                         ++pch->ppp->dev->stats.rx_length_errors;
1997                         ppp_receive_error(pch->ppp);
1998                 }
1999                 goto done;
2000         }
2001
2002         proto = PPP_PROTO(skb);
2003         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2004                 /* put it on the channel queue */
2005                 skb_queue_tail(&pch->file.rq, skb);
2006                 /* drop old frames if queue too long */
2007                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2008                        (skb = skb_dequeue(&pch->file.rq)))
2009                         kfree_skb(skb);
2010                 wake_up_interruptible(&pch->file.rwait);
2011         } else {
2012                 ppp_do_recv(pch->ppp, skb, pch);
2013         }
2014
2015 done:
2016         read_unlock_bh(&pch->upl);
2017 }
2018
2019 /* Put a 0-length skb in the receive queue as an error indication */
2020 void
2021 ppp_input_error(struct ppp_channel *chan, int code)
2022 {
2023         struct channel *pch = chan->ppp;
2024         struct sk_buff *skb;
2025
2026         if (!pch)
2027                 return;
2028
2029         read_lock_bh(&pch->upl);
2030         if (pch->ppp) {
2031                 skb = alloc_skb(0, GFP_ATOMIC);
2032                 if (skb) {
2033                         skb->len = 0;           /* probably unnecessary */
2034                         skb->cb[0] = code;
2035                         ppp_do_recv(pch->ppp, skb, pch);
2036                 }
2037         }
2038         read_unlock_bh(&pch->upl);
2039 }
2040
2041 /*
2042  * We come in here to process a received frame.
2043  * The receive side of the ppp unit is locked.
2044  */
2045 static void
2046 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2047 {
2048         /* note: a 0-length skb is used as an error indication */
2049         if (skb->len > 0) {
2050                 skb_checksum_complete_unset(skb);
2051 #ifdef CONFIG_PPP_MULTILINK
2052                 /* XXX do channel-level decompression here */
2053                 if (PPP_PROTO(skb) == PPP_MP)
2054                         ppp_receive_mp_frame(ppp, skb, pch);
2055                 else
2056 #endif /* CONFIG_PPP_MULTILINK */
2057                         ppp_receive_nonmp_frame(ppp, skb);
2058         } else {
2059                 kfree_skb(skb);
2060                 ppp_receive_error(ppp);
2061         }
2062 }
2063
2064 static void
2065 ppp_receive_error(struct ppp *ppp)
2066 {
2067         ++ppp->dev->stats.rx_errors;
2068         if (ppp->vj)
2069                 slhc_toss(ppp->vj);
2070 }
2071
2072 static void
2073 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2074 {
2075         struct sk_buff *ns;
2076         int proto, len, npi;
2077
2078         /*
2079          * Decompress the frame, if compressed.
2080          * Note that some decompressors need to see uncompressed frames
2081          * that come in as well as compressed frames.
2082          */
2083         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2084             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2085                 skb = ppp_decompress_frame(ppp, skb);
2086
2087         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2088                 goto err;
2089
2090         proto = PPP_PROTO(skb);
2091         switch (proto) {
2092         case PPP_VJC_COMP:
2093                 /* decompress VJ compressed packets */
2094                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2095                         goto err;
2096
2097                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2098                         /* copy to a new sk_buff with more tailroom */
2099                         ns = dev_alloc_skb(skb->len + 128);
2100                         if (!ns) {
2101                                 netdev_err(ppp->dev, "PPP: no memory "
2102                                            "(VJ decomp)\n");
2103                                 goto err;
2104                         }
2105                         skb_reserve(ns, 2);
2106                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2107                         consume_skb(skb);
2108                         skb = ns;
2109                 }
2110                 else
2111                         skb->ip_summed = CHECKSUM_NONE;
2112
2113                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2114                 if (len <= 0) {
2115                         netdev_printk(KERN_DEBUG, ppp->dev,
2116                                       "PPP: VJ decompression error\n");
2117                         goto err;
2118                 }
2119                 len += 2;
2120                 if (len > skb->len)
2121                         skb_put(skb, len - skb->len);
2122                 else if (len < skb->len)
2123                         skb_trim(skb, len);
2124                 proto = PPP_IP;
2125                 break;
2126
2127         case PPP_VJC_UNCOMP:
2128                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2129                         goto err;
2130
2131                 /* Until we fix the decompressor need to make sure
2132                  * data portion is linear.
2133                  */
2134                 if (!pskb_may_pull(skb, skb->len))
2135                         goto err;
2136
2137                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2138                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2139                         goto err;
2140                 }
2141                 proto = PPP_IP;
2142                 break;
2143
2144         case PPP_CCP:
2145                 ppp_ccp_peek(ppp, skb, 1);
2146                 break;
2147         }
2148
2149         ++ppp->stats64.rx_packets;
2150         ppp->stats64.rx_bytes += skb->len - 2;
2151
2152         npi = proto_to_npindex(proto);
2153         if (npi < 0) {
2154                 /* control or unknown frame - pass it to pppd */
2155                 skb_queue_tail(&ppp->file.rq, skb);
2156                 /* limit queue length by dropping old frames */
2157                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2158                        (skb = skb_dequeue(&ppp->file.rq)))
2159                         kfree_skb(skb);
2160                 /* wake up any process polling or blocking on read */
2161                 wake_up_interruptible(&ppp->file.rwait);
2162
2163         } else {
2164                 /* network protocol frame - give it to the kernel */
2165
2166 #ifdef CONFIG_PPP_FILTER
2167                 /* check if the packet passes the pass and active filters */
2168                 /* the filter instructions are constructed assuming
2169                    a four-byte PPP header on each packet */
2170                 if (ppp->pass_filter || ppp->active_filter) {
2171                         if (skb_unclone(skb, GFP_ATOMIC))
2172                                 goto err;
2173
2174                         *(u8 *)skb_push(skb, 2) = 0;
2175                         if (ppp->pass_filter &&
2176                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2177                                 if (ppp->debug & 1)
2178                                         netdev_printk(KERN_DEBUG, ppp->dev,
2179                                                       "PPP: inbound frame "
2180                                                       "not passed\n");
2181                                 kfree_skb(skb);
2182                                 return;
2183                         }
2184                         if (!(ppp->active_filter &&
2185                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2186                                 ppp->last_recv = jiffies;
2187                         __skb_pull(skb, 2);
2188                 } else
2189 #endif /* CONFIG_PPP_FILTER */
2190                         ppp->last_recv = jiffies;
2191
2192                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2193                     ppp->npmode[npi] != NPMODE_PASS) {
2194                         kfree_skb(skb);
2195                 } else {
2196                         /* chop off protocol */
2197                         skb_pull_rcsum(skb, 2);
2198                         skb->dev = ppp->dev;
2199                         skb->protocol = htons(npindex_to_ethertype[npi]);
2200                         skb_reset_mac_header(skb);
2201                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2202                                                       dev_net(ppp->dev)));
2203                         netif_rx(skb);
2204                 }
2205         }
2206         return;
2207
2208  err:
2209         kfree_skb(skb);
2210         ppp_receive_error(ppp);
2211 }
2212
2213 static struct sk_buff *
2214 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2215 {
2216         int proto = PPP_PROTO(skb);
2217         struct sk_buff *ns;
2218         int len;
2219
2220         /* Until we fix all the decompressor's need to make sure
2221          * data portion is linear.
2222          */
2223         if (!pskb_may_pull(skb, skb->len))
2224                 goto err;
2225
2226         if (proto == PPP_COMP) {
2227                 int obuff_size;
2228
2229                 switch(ppp->rcomp->compress_proto) {
2230                 case CI_MPPE:
2231                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2232                         break;
2233                 default:
2234                         obuff_size = ppp->mru + PPP_HDRLEN;
2235                         break;
2236                 }
2237
2238                 ns = dev_alloc_skb(obuff_size);
2239                 if (!ns) {
2240                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2241                                    "no memory\n");
2242                         goto err;
2243                 }
2244                 /* the decompressor still expects the A/C bytes in the hdr */
2245                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2246                                 skb->len + 2, ns->data, obuff_size);
2247                 if (len < 0) {
2248                         /* Pass the compressed frame to pppd as an
2249                            error indication. */
2250                         if (len == DECOMP_FATALERROR)
2251                                 ppp->rstate |= SC_DC_FERROR;
2252                         kfree_skb(ns);
2253                         goto err;
2254                 }
2255
2256                 consume_skb(skb);
2257                 skb = ns;
2258                 skb_put(skb, len);
2259                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2260
2261         } else {
2262                 /* Uncompressed frame - pass to decompressor so it
2263                    can update its dictionary if necessary. */
2264                 if (ppp->rcomp->incomp)
2265                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2266                                            skb->len + 2);
2267         }
2268
2269         return skb;
2270
2271  err:
2272         ppp->rstate |= SC_DC_ERROR;
2273         ppp_receive_error(ppp);
2274         return skb;
2275 }
2276
2277 #ifdef CONFIG_PPP_MULTILINK
2278 /*
2279  * Receive a multilink frame.
2280  * We put it on the reconstruction queue and then pull off
2281  * as many completed frames as we can.
2282  */
2283 static void
2284 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2285 {
2286         u32 mask, seq;
2287         struct channel *ch;
2288         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2289
2290         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2291                 goto err;               /* no good, throw it away */
2292
2293         /* Decode sequence number and begin/end bits */
2294         if (ppp->flags & SC_MP_SHORTSEQ) {
2295                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2296                 mask = 0xfff;
2297         } else {
2298                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2299                 mask = 0xffffff;
2300         }
2301         PPP_MP_CB(skb)->BEbits = skb->data[2];
2302         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2303
2304         /*
2305          * Do protocol ID decompression on the first fragment of each packet.
2306          */
2307         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2308                 *(u8 *)skb_push(skb, 1) = 0;
2309
2310         /*
2311          * Expand sequence number to 32 bits, making it as close
2312          * as possible to ppp->minseq.
2313          */
2314         seq |= ppp->minseq & ~mask;
2315         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2316                 seq += mask + 1;
2317         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2318                 seq -= mask + 1;        /* should never happen */
2319         PPP_MP_CB(skb)->sequence = seq;
2320         pch->lastseq = seq;
2321
2322         /*
2323          * If this packet comes before the next one we were expecting,
2324          * drop it.
2325          */
2326         if (seq_before(seq, ppp->nextseq)) {
2327                 kfree_skb(skb);
2328                 ++ppp->dev->stats.rx_dropped;
2329                 ppp_receive_error(ppp);
2330                 return;
2331         }
2332
2333         /*
2334          * Reevaluate minseq, the minimum over all channels of the
2335          * last sequence number received on each channel.  Because of
2336          * the increasing sequence number rule, we know that any fragment
2337          * before `minseq' which hasn't arrived is never going to arrive.
2338          * The list of channels can't change because we have the receive
2339          * side of the ppp unit locked.
2340          */
2341         list_for_each_entry(ch, &ppp->channels, clist) {
2342                 if (seq_before(ch->lastseq, seq))
2343                         seq = ch->lastseq;
2344         }
2345         if (seq_before(ppp->minseq, seq))
2346                 ppp->minseq = seq;
2347
2348         /* Put the fragment on the reconstruction queue */
2349         ppp_mp_insert(ppp, skb);
2350
2351         /* If the queue is getting long, don't wait any longer for packets
2352            before the start of the queue. */
2353         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2354                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2355                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2356                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2357         }
2358
2359         /* Pull completed packets off the queue and receive them. */
2360         while ((skb = ppp_mp_reconstruct(ppp))) {
2361                 if (pskb_may_pull(skb, 2))
2362                         ppp_receive_nonmp_frame(ppp, skb);
2363                 else {
2364                         ++ppp->dev->stats.rx_length_errors;
2365                         kfree_skb(skb);
2366                         ppp_receive_error(ppp);
2367                 }
2368         }
2369
2370         return;
2371
2372  err:
2373         kfree_skb(skb);
2374         ppp_receive_error(ppp);
2375 }
2376
2377 /*
2378  * Insert a fragment on the MP reconstruction queue.
2379  * The queue is ordered by increasing sequence number.
2380  */
2381 static void
2382 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2383 {
2384         struct sk_buff *p;
2385         struct sk_buff_head *list = &ppp->mrq;
2386         u32 seq = PPP_MP_CB(skb)->sequence;
2387
2388         /* N.B. we don't need to lock the list lock because we have the
2389            ppp unit receive-side lock. */
2390         skb_queue_walk(list, p) {
2391                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2392                         break;
2393         }
2394         __skb_queue_before(list, p, skb);
2395 }
2396
2397 /*
2398  * Reconstruct a packet from the MP fragment queue.
2399  * We go through increasing sequence numbers until we find a
2400  * complete packet, or we get to the sequence number for a fragment
2401  * which hasn't arrived but might still do so.
2402  */
2403 static struct sk_buff *
2404 ppp_mp_reconstruct(struct ppp *ppp)
2405 {
2406         u32 seq = ppp->nextseq;
2407         u32 minseq = ppp->minseq;
2408         struct sk_buff_head *list = &ppp->mrq;
2409         struct sk_buff *p, *tmp;
2410         struct sk_buff *head, *tail;
2411         struct sk_buff *skb = NULL;
2412         int lost = 0, len = 0;
2413
2414         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2415                 return NULL;
2416         head = list->next;
2417         tail = NULL;
2418         skb_queue_walk_safe(list, p, tmp) {
2419         again:
2420                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2421                         /* this can't happen, anyway ignore the skb */
2422                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2423                                    "seq %u < %u\n",
2424                                    PPP_MP_CB(p)->sequence, seq);
2425                         __skb_unlink(p, list);
2426                         kfree_skb(p);
2427                         continue;
2428                 }
2429                 if (PPP_MP_CB(p)->sequence != seq) {
2430                         u32 oldseq;
2431                         /* Fragment `seq' is missing.  If it is after
2432                            minseq, it might arrive later, so stop here. */
2433                         if (seq_after(seq, minseq))
2434                                 break;
2435                         /* Fragment `seq' is lost, keep going. */
2436                         lost = 1;
2437                         oldseq = seq;
2438                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2439                                 minseq + 1: PPP_MP_CB(p)->sequence;
2440
2441                         if (ppp->debug & 1)
2442                                 netdev_printk(KERN_DEBUG, ppp->dev,
2443                                               "lost frag %u..%u\n",
2444                                               oldseq, seq-1);
2445
2446                         goto again;
2447                 }
2448
2449                 /*
2450                  * At this point we know that all the fragments from
2451                  * ppp->nextseq to seq are either present or lost.
2452                  * Also, there are no complete packets in the queue
2453                  * that have no missing fragments and end before this
2454                  * fragment.
2455                  */
2456
2457                 /* B bit set indicates this fragment starts a packet */
2458                 if (PPP_MP_CB(p)->BEbits & B) {
2459                         head = p;
2460                         lost = 0;
2461                         len = 0;
2462                 }
2463
2464                 len += p->len;
2465
2466                 /* Got a complete packet yet? */
2467                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2468                     (PPP_MP_CB(head)->BEbits & B)) {
2469                         if (len > ppp->mrru + 2) {
2470                                 ++ppp->dev->stats.rx_length_errors;
2471                                 netdev_printk(KERN_DEBUG, ppp->dev,
2472                                               "PPP: reconstructed packet"
2473                                               " is too long (%d)\n", len);
2474                         } else {
2475                                 tail = p;
2476                                 break;
2477                         }
2478                         ppp->nextseq = seq + 1;
2479                 }
2480
2481                 /*
2482                  * If this is the ending fragment of a packet,
2483                  * and we haven't found a complete valid packet yet,
2484                  * we can discard up to and including this fragment.
2485                  */
2486                 if (PPP_MP_CB(p)->BEbits & E) {
2487                         struct sk_buff *tmp2;
2488
2489                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2490                                 if (ppp->debug & 1)
2491                                         netdev_printk(KERN_DEBUG, ppp->dev,
2492                                                       "discarding frag %u\n",
2493                                                       PPP_MP_CB(p)->sequence);
2494                                 __skb_unlink(p, list);
2495                                 kfree_skb(p);
2496                         }
2497                         head = skb_peek(list);
2498                         if (!head)
2499                                 break;
2500                 }
2501                 ++seq;
2502         }
2503
2504         /* If we have a complete packet, copy it all into one skb. */
2505         if (tail != NULL) {
2506                 /* If we have discarded any fragments,
2507                    signal a receive error. */
2508                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2509                         skb_queue_walk_safe(list, p, tmp) {
2510                                 if (p == head)
2511                                         break;
2512                                 if (ppp->debug & 1)
2513                                         netdev_printk(KERN_DEBUG, ppp->dev,
2514                                                       "discarding frag %u\n",
2515                                                       PPP_MP_CB(p)->sequence);
2516                                 __skb_unlink(p, list);
2517                                 kfree_skb(p);
2518                         }
2519
2520                         if (ppp->debug & 1)
2521                                 netdev_printk(KERN_DEBUG, ppp->dev,
2522                                               "  missed pkts %u..%u\n",
2523                                               ppp->nextseq,
2524                                               PPP_MP_CB(head)->sequence-1);
2525                         ++ppp->dev->stats.rx_dropped;
2526                         ppp_receive_error(ppp);
2527                 }
2528
2529                 skb = head;
2530                 if (head != tail) {
2531                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2532                         p = skb_queue_next(list, head);
2533                         __skb_unlink(skb, list);
2534                         skb_queue_walk_from_safe(list, p, tmp) {
2535                                 __skb_unlink(p, list);
2536                                 *fragpp = p;
2537                                 p->next = NULL;
2538                                 fragpp = &p->next;
2539
2540                                 skb->len += p->len;
2541                                 skb->data_len += p->len;
2542                                 skb->truesize += p->truesize;
2543
2544                                 if (p == tail)
2545                                         break;
2546                         }
2547                 } else {
2548                         __skb_unlink(skb, list);
2549                 }
2550
2551                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2552         }
2553
2554         return skb;
2555 }
2556 #endif /* CONFIG_PPP_MULTILINK */
2557
2558 /*
2559  * Channel interface.
2560  */
2561
2562 /* Create a new, unattached ppp channel. */
2563 int ppp_register_channel(struct ppp_channel *chan)
2564 {
2565         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2566 }
2567
2568 /* Create a new, unattached ppp channel for specified net. */
2569 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2570 {
2571         struct channel *pch;
2572         struct ppp_net *pn;
2573
2574         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2575         if (!pch)
2576                 return -ENOMEM;
2577
2578         pn = ppp_pernet(net);
2579
2580         pch->ppp = NULL;
2581         pch->chan = chan;
2582         pch->chan_net = get_net(net);
2583         chan->ppp = pch;
2584         init_ppp_file(&pch->file, CHANNEL);
2585         pch->file.hdrlen = chan->hdrlen;
2586 #ifdef CONFIG_PPP_MULTILINK
2587         pch->lastseq = -1;
2588 #endif /* CONFIG_PPP_MULTILINK */
2589         init_rwsem(&pch->chan_sem);
2590         spin_lock_init(&pch->downl);
2591         rwlock_init(&pch->upl);
2592
2593         spin_lock_bh(&pn->all_channels_lock);
2594         pch->file.index = ++pn->last_channel_index;
2595         list_add(&pch->list, &pn->new_channels);
2596         atomic_inc(&channel_count);
2597         spin_unlock_bh(&pn->all_channels_lock);
2598
2599         return 0;
2600 }
2601
2602 /*
2603  * Return the index of a channel.
2604  */
2605 int ppp_channel_index(struct ppp_channel *chan)
2606 {
2607         struct channel *pch = chan->ppp;
2608
2609         if (pch)
2610                 return pch->file.index;
2611         return -1;
2612 }
2613
2614 /*
2615  * Return the PPP unit number to which a channel is connected.
2616  */
2617 int ppp_unit_number(struct ppp_channel *chan)
2618 {
2619         struct channel *pch = chan->ppp;
2620         int unit = -1;
2621
2622         if (pch) {
2623                 read_lock_bh(&pch->upl);
2624                 if (pch->ppp)
2625                         unit = pch->ppp->file.index;
2626                 read_unlock_bh(&pch->upl);
2627         }
2628         return unit;
2629 }
2630
2631 /*
2632  * Return the PPP device interface name of a channel.
2633  */
2634 char *ppp_dev_name(struct ppp_channel *chan)
2635 {
2636         struct channel *pch = chan->ppp;
2637         char *name = NULL;
2638
2639         if (pch) {
2640                 read_lock_bh(&pch->upl);
2641                 if (pch->ppp && pch->ppp->dev)
2642                         name = pch->ppp->dev->name;
2643                 read_unlock_bh(&pch->upl);
2644         }
2645         return name;
2646 }
2647
2648
2649 /*
2650  * Disconnect a channel from the generic layer.
2651  * This must be called in process context.
2652  */
2653 void
2654 ppp_unregister_channel(struct ppp_channel *chan)
2655 {
2656         struct channel *pch = chan->ppp;
2657         struct ppp_net *pn;
2658
2659         if (!pch)
2660                 return;         /* should never happen */
2661
2662         chan->ppp = NULL;
2663
2664         /*
2665          * This ensures that we have returned from any calls into the
2666          * the channel's start_xmit or ioctl routine before we proceed.
2667          */
2668         down_write(&pch->chan_sem);
2669         spin_lock_bh(&pch->downl);
2670         pch->chan = NULL;
2671         spin_unlock_bh(&pch->downl);
2672         up_write(&pch->chan_sem);
2673         ppp_disconnect_channel(pch);
2674
2675         pn = ppp_pernet(pch->chan_net);
2676         spin_lock_bh(&pn->all_channels_lock);
2677         list_del(&pch->list);
2678         spin_unlock_bh(&pn->all_channels_lock);
2679
2680         pch->file.dead = 1;
2681         wake_up_interruptible(&pch->file.rwait);
2682         if (refcount_dec_and_test(&pch->file.refcnt))
2683                 ppp_destroy_channel(pch);
2684 }
2685
2686 /*
2687  * Callback from a channel when it can accept more to transmit.
2688  * This should be called at BH/softirq level, not interrupt level.
2689  */
2690 void
2691 ppp_output_wakeup(struct ppp_channel *chan)
2692 {
2693         struct channel *pch = chan->ppp;
2694
2695         if (!pch)
2696                 return;
2697         ppp_channel_push(pch);
2698 }
2699
2700 /*
2701  * Compression control.
2702  */
2703
2704 /* Process the PPPIOCSCOMPRESS ioctl. */
2705 static int
2706 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2707 {
2708         int err;
2709         struct compressor *cp, *ocomp;
2710         struct ppp_option_data data;
2711         void *state, *ostate;
2712         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2713
2714         err = -EFAULT;
2715         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2716                 goto out;
2717         if (data.length > CCP_MAX_OPTION_LENGTH)
2718                 goto out;
2719         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2720                 goto out;
2721
2722         err = -EINVAL;
2723         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2724                 goto out;
2725
2726         cp = try_then_request_module(
2727                 find_compressor(ccp_option[0]),
2728                 "ppp-compress-%d", ccp_option[0]);
2729         if (!cp)
2730                 goto out;
2731
2732         err = -ENOBUFS;
2733         if (data.transmit) {
2734                 state = cp->comp_alloc(ccp_option, data.length);
2735                 if (state) {
2736                         ppp_xmit_lock(ppp);
2737                         ppp->xstate &= ~SC_COMP_RUN;
2738                         ocomp = ppp->xcomp;
2739                         ostate = ppp->xc_state;
2740                         ppp->xcomp = cp;
2741                         ppp->xc_state = state;
2742                         ppp_xmit_unlock(ppp);
2743                         if (ostate) {
2744                                 ocomp->comp_free(ostate);
2745                                 module_put(ocomp->owner);
2746                         }
2747                         err = 0;
2748                 } else
2749                         module_put(cp->owner);
2750
2751         } else {
2752                 state = cp->decomp_alloc(ccp_option, data.length);
2753                 if (state) {
2754                         ppp_recv_lock(ppp);
2755                         ppp->rstate &= ~SC_DECOMP_RUN;
2756                         ocomp = ppp->rcomp;
2757                         ostate = ppp->rc_state;
2758                         ppp->rcomp = cp;
2759                         ppp->rc_state = state;
2760                         ppp_recv_unlock(ppp);
2761                         if (ostate) {
2762                                 ocomp->decomp_free(ostate);
2763                                 module_put(ocomp->owner);
2764                         }
2765                         err = 0;
2766                 } else
2767                         module_put(cp->owner);
2768         }
2769
2770  out:
2771         return err;
2772 }
2773
2774 /*
2775  * Look at a CCP packet and update our state accordingly.
2776  * We assume the caller has the xmit or recv path locked.
2777  */
2778 static void
2779 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2780 {
2781         unsigned char *dp;
2782         int len;
2783
2784         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2785                 return; /* no header */
2786         dp = skb->data + 2;
2787
2788         switch (CCP_CODE(dp)) {
2789         case CCP_CONFREQ:
2790
2791                 /* A ConfReq starts negotiation of compression
2792                  * in one direction of transmission,
2793                  * and hence brings it down...but which way?
2794                  *
2795                  * Remember:
2796                  * A ConfReq indicates what the sender would like to receive
2797                  */
2798                 if(inbound)
2799                         /* He is proposing what I should send */
2800                         ppp->xstate &= ~SC_COMP_RUN;
2801                 else
2802                         /* I am proposing to what he should send */
2803                         ppp->rstate &= ~SC_DECOMP_RUN;
2804
2805                 break;
2806
2807         case CCP_TERMREQ:
2808         case CCP_TERMACK:
2809                 /*
2810                  * CCP is going down, both directions of transmission
2811                  */
2812                 ppp->rstate &= ~SC_DECOMP_RUN;
2813                 ppp->xstate &= ~SC_COMP_RUN;
2814                 break;
2815
2816         case CCP_CONFACK:
2817                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2818                         break;
2819                 len = CCP_LENGTH(dp);
2820                 if (!pskb_may_pull(skb, len + 2))
2821                         return;         /* too short */
2822                 dp += CCP_HDRLEN;
2823                 len -= CCP_HDRLEN;
2824                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2825                         break;
2826                 if (inbound) {
2827                         /* we will start receiving compressed packets */
2828                         if (!ppp->rc_state)
2829                                 break;
2830                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2831                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2832                                 ppp->rstate |= SC_DECOMP_RUN;
2833                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2834                         }
2835                 } else {
2836                         /* we will soon start sending compressed packets */
2837                         if (!ppp->xc_state)
2838                                 break;
2839                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2840                                         ppp->file.index, 0, ppp->debug))
2841                                 ppp->xstate |= SC_COMP_RUN;
2842                 }
2843                 break;
2844
2845         case CCP_RESETACK:
2846                 /* reset the [de]compressor */
2847                 if ((ppp->flags & SC_CCP_UP) == 0)
2848                         break;
2849                 if (inbound) {
2850                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2851                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2852                                 ppp->rstate &= ~SC_DC_ERROR;
2853                         }
2854                 } else {
2855                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2856                                 ppp->xcomp->comp_reset(ppp->xc_state);
2857                 }
2858                 break;
2859         }
2860 }
2861
2862 /* Free up compression resources. */
2863 static void
2864 ppp_ccp_closed(struct ppp *ppp)
2865 {
2866         void *xstate, *rstate;
2867         struct compressor *xcomp, *rcomp;
2868
2869         ppp_lock(ppp);
2870         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2871         ppp->xstate = 0;
2872         xcomp = ppp->xcomp;
2873         xstate = ppp->xc_state;
2874         ppp->xc_state = NULL;
2875         ppp->rstate = 0;
2876         rcomp = ppp->rcomp;
2877         rstate = ppp->rc_state;
2878         ppp->rc_state = NULL;
2879         ppp_unlock(ppp);
2880
2881         if (xstate) {
2882                 xcomp->comp_free(xstate);
2883                 module_put(xcomp->owner);
2884         }
2885         if (rstate) {
2886                 rcomp->decomp_free(rstate);
2887                 module_put(rcomp->owner);
2888         }
2889 }
2890
2891 /* List of compressors. */
2892 static LIST_HEAD(compressor_list);
2893 static DEFINE_SPINLOCK(compressor_list_lock);
2894
2895 struct compressor_entry {
2896         struct list_head list;
2897         struct compressor *comp;
2898 };
2899
2900 static struct compressor_entry *
2901 find_comp_entry(int proto)
2902 {
2903         struct compressor_entry *ce;
2904
2905         list_for_each_entry(ce, &compressor_list, list) {
2906                 if (ce->comp->compress_proto == proto)
2907                         return ce;
2908         }
2909         return NULL;
2910 }
2911
2912 /* Register a compressor */
2913 int
2914 ppp_register_compressor(struct compressor *cp)
2915 {
2916         struct compressor_entry *ce;
2917         int ret;
2918         spin_lock(&compressor_list_lock);
2919         ret = -EEXIST;
2920         if (find_comp_entry(cp->compress_proto))
2921                 goto out;
2922         ret = -ENOMEM;
2923         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2924         if (!ce)
2925                 goto out;
2926         ret = 0;
2927         ce->comp = cp;
2928         list_add(&ce->list, &compressor_list);
2929  out:
2930         spin_unlock(&compressor_list_lock);
2931         return ret;
2932 }
2933
2934 /* Unregister a compressor */
2935 void
2936 ppp_unregister_compressor(struct compressor *cp)
2937 {
2938         struct compressor_entry *ce;
2939
2940         spin_lock(&compressor_list_lock);
2941         ce = find_comp_entry(cp->compress_proto);
2942         if (ce && ce->comp == cp) {
2943                 list_del(&ce->list);
2944                 kfree(ce);
2945         }
2946         spin_unlock(&compressor_list_lock);
2947 }
2948
2949 /* Find a compressor. */
2950 static struct compressor *
2951 find_compressor(int type)
2952 {
2953         struct compressor_entry *ce;
2954         struct compressor *cp = NULL;
2955
2956         spin_lock(&compressor_list_lock);
2957         ce = find_comp_entry(type);
2958         if (ce) {
2959                 cp = ce->comp;
2960                 if (!try_module_get(cp->owner))
2961                         cp = NULL;
2962         }
2963         spin_unlock(&compressor_list_lock);
2964         return cp;
2965 }
2966
2967 /*
2968  * Miscelleneous stuff.
2969  */
2970
2971 static void
2972 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2973 {
2974         struct slcompress *vj = ppp->vj;
2975
2976         memset(st, 0, sizeof(*st));
2977         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2978         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2979         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2980         st->p.ppp_opackets = ppp->stats64.tx_packets;
2981         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2982         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2983         if (!vj)
2984                 return;
2985         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2986         st->vj.vjs_compressed = vj->sls_o_compressed;
2987         st->vj.vjs_searches = vj->sls_o_searches;
2988         st->vj.vjs_misses = vj->sls_o_misses;
2989         st->vj.vjs_errorin = vj->sls_i_error;
2990         st->vj.vjs_tossed = vj->sls_i_tossed;
2991         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2992         st->vj.vjs_compressedin = vj->sls_i_compressed;
2993 }
2994
2995 /*
2996  * Stuff for handling the lists of ppp units and channels
2997  * and for initialization.
2998  */
2999
3000 /*
3001  * Create a new ppp interface unit.  Fails if it can't allocate memory
3002  * or if there is already a unit with the requested number.
3003  * unit == -1 means allocate a new number.
3004  */
3005 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3006 {
3007         struct ppp_config conf = {
3008                 .file = file,
3009                 .unit = *unit,
3010                 .ifname_is_set = false,
3011         };
3012         struct net_device *dev;
3013         struct ppp *ppp;
3014         int err;
3015
3016         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3017         if (!dev) {
3018                 err = -ENOMEM;
3019                 goto err;
3020         }
3021         dev_net_set(dev, net);
3022         dev->rtnl_link_ops = &ppp_link_ops;
3023
3024         rtnl_lock();
3025
3026         err = ppp_dev_configure(net, dev, &conf);
3027         if (err < 0)
3028                 goto err_dev;
3029         ppp = netdev_priv(dev);
3030         *unit = ppp->file.index;
3031
3032         rtnl_unlock();
3033
3034         return 0;
3035
3036 err_dev:
3037         rtnl_unlock();
3038         free_netdev(dev);
3039 err:
3040         return err;
3041 }
3042
3043 /*
3044  * Initialize a ppp_file structure.
3045  */
3046 static void
3047 init_ppp_file(struct ppp_file *pf, int kind)
3048 {
3049         pf->kind = kind;
3050         skb_queue_head_init(&pf->xq);
3051         skb_queue_head_init(&pf->rq);
3052         refcount_set(&pf->refcnt, 1);
3053         init_waitqueue_head(&pf->rwait);
3054 }
3055
3056 /*
3057  * Free the memory used by a ppp unit.  This is only called once
3058  * there are no channels connected to the unit and no file structs
3059  * that reference the unit.
3060  */
3061 static void ppp_destroy_interface(struct ppp *ppp)
3062 {
3063         atomic_dec(&ppp_unit_count);
3064
3065         if (!ppp->file.dead || ppp->n_channels) {
3066                 /* "can't happen" */
3067                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3068                            "but dead=%d n_channels=%d !\n",
3069                            ppp, ppp->file.dead, ppp->n_channels);
3070                 return;
3071         }
3072
3073         ppp_ccp_closed(ppp);
3074         if (ppp->vj) {
3075                 slhc_free(ppp->vj);
3076                 ppp->vj = NULL;
3077         }
3078         skb_queue_purge(&ppp->file.xq);
3079         skb_queue_purge(&ppp->file.rq);
3080 #ifdef CONFIG_PPP_MULTILINK
3081         skb_queue_purge(&ppp->mrq);
3082 #endif /* CONFIG_PPP_MULTILINK */
3083 #ifdef CONFIG_PPP_FILTER
3084         if (ppp->pass_filter) {
3085                 bpf_prog_destroy(ppp->pass_filter);
3086                 ppp->pass_filter = NULL;
3087         }
3088
3089         if (ppp->active_filter) {
3090                 bpf_prog_destroy(ppp->active_filter);
3091                 ppp->active_filter = NULL;
3092         }
3093 #endif /* CONFIG_PPP_FILTER */
3094
3095         kfree_skb(ppp->xmit_pending);
3096         free_percpu(ppp->xmit_recursion);
3097
3098         free_netdev(ppp->dev);
3099 }
3100
3101 /*
3102  * Locate an existing ppp unit.
3103  * The caller should have locked the all_ppp_mutex.
3104  */
3105 static struct ppp *
3106 ppp_find_unit(struct ppp_net *pn, int unit)
3107 {
3108         return unit_find(&pn->units_idr, unit);
3109 }
3110
3111 /*
3112  * Locate an existing ppp channel.
3113  * The caller should have locked the all_channels_lock.
3114  * First we look in the new_channels list, then in the
3115  * all_channels list.  If found in the new_channels list,
3116  * we move it to the all_channels list.  This is for speed
3117  * when we have a lot of channels in use.
3118  */
3119 static struct channel *
3120 ppp_find_channel(struct ppp_net *pn, int unit)
3121 {
3122         struct channel *pch;
3123
3124         list_for_each_entry(pch, &pn->new_channels, list) {
3125                 if (pch->file.index == unit) {
3126                         list_move(&pch->list, &pn->all_channels);
3127                         return pch;
3128                 }
3129         }
3130
3131         list_for_each_entry(pch, &pn->all_channels, list) {
3132                 if (pch->file.index == unit)
3133                         return pch;
3134         }
3135
3136         return NULL;
3137 }
3138
3139 /*
3140  * Connect a PPP channel to a PPP interface unit.
3141  */
3142 static int
3143 ppp_connect_channel(struct channel *pch, int unit)
3144 {
3145         struct ppp *ppp;
3146         struct ppp_net *pn;
3147         int ret = -ENXIO;
3148         int hdrlen;
3149
3150         pn = ppp_pernet(pch->chan_net);
3151
3152         mutex_lock(&pn->all_ppp_mutex);
3153         ppp = ppp_find_unit(pn, unit);
3154         if (!ppp)
3155                 goto out;
3156         write_lock_bh(&pch->upl);
3157         ret = -EINVAL;
3158         if (pch->ppp)
3159                 goto outl;
3160
3161         ppp_lock(ppp);
3162         spin_lock_bh(&pch->downl);
3163         if (!pch->chan) {
3164                 /* Don't connect unregistered channels */
3165                 spin_unlock_bh(&pch->downl);
3166                 ppp_unlock(ppp);
3167                 ret = -ENOTCONN;
3168                 goto outl;
3169         }
3170         spin_unlock_bh(&pch->downl);
3171         if (pch->file.hdrlen > ppp->file.hdrlen)
3172                 ppp->file.hdrlen = pch->file.hdrlen;
3173         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3174         if (hdrlen > ppp->dev->hard_header_len)
3175                 ppp->dev->hard_header_len = hdrlen;
3176         list_add_tail(&pch->clist, &ppp->channels);
3177         ++ppp->n_channels;
3178         pch->ppp = ppp;
3179         refcount_inc(&ppp->file.refcnt);
3180         ppp_unlock(ppp);
3181         ret = 0;
3182
3183  outl:
3184         write_unlock_bh(&pch->upl);
3185  out:
3186         mutex_unlock(&pn->all_ppp_mutex);
3187         return ret;
3188 }
3189
3190 /*
3191  * Disconnect a channel from its ppp unit.
3192  */
3193 static int
3194 ppp_disconnect_channel(struct channel *pch)
3195 {
3196         struct ppp *ppp;
3197         int err = -EINVAL;
3198
3199         write_lock_bh(&pch->upl);
3200         ppp = pch->ppp;
3201         pch->ppp = NULL;
3202         write_unlock_bh(&pch->upl);
3203         if (ppp) {
3204                 /* remove it from the ppp unit's list */
3205                 ppp_lock(ppp);
3206                 list_del(&pch->clist);
3207                 if (--ppp->n_channels == 0)
3208                         wake_up_interruptible(&ppp->file.rwait);
3209                 ppp_unlock(ppp);
3210                 if (refcount_dec_and_test(&ppp->file.refcnt))
3211                         ppp_destroy_interface(ppp);
3212                 err = 0;
3213         }
3214         return err;
3215 }
3216
3217 /*
3218  * Free up the resources used by a ppp channel.
3219  */
3220 static void ppp_destroy_channel(struct channel *pch)
3221 {
3222         put_net(pch->chan_net);
3223         pch->chan_net = NULL;
3224
3225         atomic_dec(&channel_count);
3226
3227         if (!pch->file.dead) {
3228                 /* "can't happen" */
3229                 pr_err("ppp: destroying undead channel %p !\n", pch);
3230                 return;
3231         }
3232         skb_queue_purge(&pch->file.xq);
3233         skb_queue_purge(&pch->file.rq);
3234         kfree(pch);
3235 }
3236
3237 static void __exit ppp_cleanup(void)
3238 {
3239         /* should never happen */
3240         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3241                 pr_err("PPP: removing module but units remain!\n");
3242         rtnl_link_unregister(&ppp_link_ops);
3243         unregister_chrdev(PPP_MAJOR, "ppp");
3244         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3245         class_destroy(ppp_class);
3246         unregister_pernet_device(&ppp_net_ops);
3247 }
3248
3249 /*
3250  * Units handling. Caller must protect concurrent access
3251  * by holding all_ppp_mutex
3252  */
3253
3254 /* associate pointer with specified number */
3255 static int unit_set(struct idr *p, void *ptr, int n)
3256 {
3257         int unit;
3258
3259         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3260         if (unit == -ENOSPC)
3261                 unit = -EINVAL;
3262         return unit;
3263 }
3264
3265 /* get new free unit number and associate pointer with it */
3266 static int unit_get(struct idr *p, void *ptr, int min)
3267 {
3268         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3269 }
3270
3271 /* put unit number back to a pool */
3272 static void unit_put(struct idr *p, int n)
3273 {
3274         idr_remove(p, n);
3275 }
3276
3277 /* get pointer associated with the number */
3278 static void *unit_find(struct idr *p, int n)
3279 {
3280         return idr_find(p, n);
3281 }
3282
3283 /* Module/initialization stuff */
3284
3285 module_init(ppp_init);
3286 module_exit(ppp_cleanup);
3287
3288 EXPORT_SYMBOL(ppp_register_net_channel);
3289 EXPORT_SYMBOL(ppp_register_channel);
3290 EXPORT_SYMBOL(ppp_unregister_channel);
3291 EXPORT_SYMBOL(ppp_channel_index);
3292 EXPORT_SYMBOL(ppp_unit_number);
3293 EXPORT_SYMBOL(ppp_dev_name);
3294 EXPORT_SYMBOL(ppp_input);
3295 EXPORT_SYMBOL(ppp_input_error);
3296 EXPORT_SYMBOL(ppp_output_wakeup);
3297 EXPORT_SYMBOL(ppp_register_compressor);
3298 EXPORT_SYMBOL(ppp_unregister_compressor);
3299 MODULE_LICENSE("GPL");
3300 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3301 MODULE_ALIAS_RTNL_LINK("ppp");
3302 MODULE_ALIAS("devname:ppp");