drivers/net/ppp/ppp_generic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic PPP layer for Linux.
   4  *
   5  * Copyright 1999-2002 Paul Mackerras.
   6  *
   7  * The generic PPP layer handles the PPP network interfaces, the
   8  * /dev/ppp device, packet and VJ compression, and multilink.
   9  * It talks to PPP `channels' via the interface defined in
  10  * include/linux/ppp_channel.h.  Channels provide the basic means for
  11  * sending and receiving PPP frames on some kind of communications
  12  * channel.
  13  *
  14  * Part of the code in this driver was inspired by the old async-only
  15  * PPP driver, written by Michael Callahan and Al Longyear, and
  16  * subsequently hacked by Paul Mackerras.
  17  *
  18  * ==FILEVERSION 20041108==
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched/signal.h>
  24 #include <linux/kmod.h>
  25 #include <linux/init.h>
  26 #include <linux/list.h>
  27 #include <linux/idr.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/poll.h>
  30 #include <linux/ppp_defs.h>
  31 #include <linux/filter.h>
  32 #include <linux/ppp-ioctl.h>
  33 #include <linux/ppp_channel.h>
  34 #include <linux/ppp-comp.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/rtnetlink.h>
  37 #include <linux/if_arp.h>
  38 #include <linux/ip.h>
  39 #include <linux/tcp.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/rwsem.h>
  42 #include <linux/stddef.h>
  43 #include <linux/device.h>
  44 #include <linux/mutex.h>
  45 #include <linux/slab.h>
  46 #include <linux/file.h>
  47 #include <asm/unaligned.h>
  48 #include <net/slhc_vj.h>
  49 #include <linux/atomic.h>
  50 #include <linux/refcount.h>
  51
  52 #include <linux/nsproxy.h>
  53 #include <net/net_namespace.h>
  54 #include <net/netns/generic.h>
  55
  56 #define PPP_VERSION     "2.4.2"
  57
  58 /*
  59  * Network protocols we support.
  60  */
  61 #define NP_IP   0               /* Internet Protocol V4 */
  62 #define NP_IPV6 1               /* Internet Protocol V6 */
  63 #define NP_IPX  2               /* IPX protocol */
  64 #define NP_AT   3               /* Appletalk protocol */
  65 #define NP_MPLS_UC 4            /* MPLS unicast */
  66 #define NP_MPLS_MC 5            /* MPLS multicast */
  67 #define NUM_NP  6               /* Number of NPs. */
  68
  69 #define MPHDRLEN        6       /* multilink protocol header length */
  70 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  71
  72 /*
  73  * An instance of /dev/ppp can be associated with either a ppp
  74  * interface unit or a ppp channel.  In both cases, file->private_data
  75  * points to one of these.
  76  */
  77 struct ppp_file {
  78         enum {
  79                 INTERFACE=1, CHANNEL
  80         }               kind;
  81         struct sk_buff_head xq;         /* pppd transmit queue */
  82         struct sk_buff_head rq;         /* receive queue for pppd */
  83         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  84         refcount_t      refcnt;         /* # refs (incl /dev/ppp attached) */
  85         int             hdrlen;         /* space to leave for headers */
  86         int             index;          /* interface unit / channel number */
  87         int             dead;           /* unit/channel has been shut down */
  88 };
  89
  90 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  91
  92 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  93 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  94
  95 /*
  96  * Data structure to hold primary network stats for which
  97  * we want to use 64 bit storage.  Other network stats
  98  * are stored in dev->stats of the ppp strucute.
  99  */
 100 struct ppp_link_stats {
 101         u64 rx_packets;
 102         u64 tx_packets;
 103         u64 rx_bytes;
 104         u64 tx_bytes;
 105 };
 106
 107 /*
 108  * Data structure describing one ppp unit.
 109  * A ppp unit corresponds to a ppp network interface device
 110  * and represents a multilink bundle.
 111  * It can have 0 or more ppp channels connected to it.
 112  */
 113 struct ppp {
 114         struct ppp_file file;           /* stuff for read/write/poll 0 */
 115         struct file     *owner;         /* file that owns this unit 48 */
 116         struct list_head channels;      /* list of attached channels 4c */
 117         int             n_channels;     /* how many channels are attached 54 */
 118         spinlock_t      rlock;          /* lock for receive side 58 */
 119         spinlock_t      wlock;          /* lock for transmit side 5c */
 120         int __percpu    *xmit_recursion; /* xmit recursion detect */
 121         int             mru;            /* max receive unit 60 */
 122         unsigned int    flags;          /* control bits 64 */
 123         unsigned int    xstate;         /* transmit state bits 68 */
 124         unsigned int    rstate;         /* receive state bits 6c */
 125         int             debug;          /* debug flags 70 */
 126         struct slcompress *vj;          /* state for VJ header compression */
 127         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 128         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 129         struct compressor *xcomp;       /* transmit packet compressor 8c */
 130         void            *xc_state;      /* its internal state 90 */
 131         struct compressor *rcomp;       /* receive decompressor 94 */
 132         void            *rc_state;      /* its internal state 98 */
 133         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 134         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 135         struct net_device *dev;         /* network interface device a4 */
 136         int             closing;        /* is device closing down? a8 */
 137 #ifdef CONFIG_PPP_MULTILINK
 138         int             nxchan;         /* next channel to send something on */
 139         u32             nxseq;          /* next sequence number to send */
 140         int             mrru;           /* MP: max reconst. receive unit */
 141         u32             nextseq;        /* MP: seq no of next packet */
 142         u32             minseq;         /* MP: min of most recent seqnos */
 143         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 144 #endif /* CONFIG_PPP_MULTILINK */
 145 #ifdef CONFIG_PPP_FILTER
 146         struct bpf_prog *pass_filter;   /* filter for packets to pass */
 147         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 148 #endif /* CONFIG_PPP_FILTER */
 149         struct net      *ppp_net;       /* the net we belong to */
 150         struct ppp_link_stats stats64;  /* 64 bit network stats */
 151 };
 152
 153 /*
 154  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 155  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 156  * SC_MUST_COMP
 157  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 158  * Bits in xstate: SC_COMP_RUN
 159  */
 160 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 161                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 162                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 163
 164 /*
 165  * Private data structure for each channel.
 166  * This includes the data structure used for multilink.
 167  */
 168 struct channel {
 169         struct ppp_file file;           /* stuff for read/write/poll */
 170         struct list_head list;          /* link in all/new_channels list */
 171         struct ppp_channel *chan;       /* public channel data structure */
 172         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 173         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 174         struct ppp      *ppp;           /* ppp unit we're connected to */
 175         struct net      *chan_net;      /* the net channel belongs to */
 176         struct list_head clist;         /* link in list of channels per unit */
 177         rwlock_t        upl;            /* protects `ppp' and 'bridge' */
 178         struct channel __rcu *bridge;   /* "bridged" ppp channel */
 179 #ifdef CONFIG_PPP_MULTILINK
 180         u8              avail;          /* flag used in multilink stuff */
 181         u8              had_frag;       /* >= 1 fragments have been sent */
 182         u32             lastseq;        /* MP: last sequence # received */
 183         int             speed;          /* speed of the corresponding ppp channel*/
 184 #endif /* CONFIG_PPP_MULTILINK */
 185 };
 186
 187 struct ppp_config {
 188         struct file *file;
 189         s32 unit;
 190         bool ifname_is_set;
 191 };
 192
 193 /*
 194  * SMP locking issues:
 195  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 196  * list and the ppp.n_channels field, you need to take both locks
 197  * before you modify them.
 198  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 199  * channel.downl.
 200  */
 201
 202 static DEFINE_MUTEX(ppp_mutex);
 203 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 204 static atomic_t channel_count = ATOMIC_INIT(0);
 205
 206 /* per-net private data for this module */
 207 static unsigned int ppp_net_id __read_mostly;
 208 struct ppp_net {
 209         /* units to ppp mapping */
 210         struct idr units_idr;
 211
 212         /*
 213          * all_ppp_mutex protects the units_idr mapping.
 214          * It also ensures that finding a ppp unit in the units_idr
 215          * map and updating its file.refcnt field is atomic.
 216          */
 217         struct mutex all_ppp_mutex;
 218
 219         /* channels */
 220         struct list_head all_channels;
 221         struct list_head new_channels;
 222         int last_channel_index;
 223
 224         /*
 225          * all_channels_lock protects all_channels and
 226          * last_channel_index, and the atomicity of find
 227          * a channel and updating its file.refcnt field.
 228          */
 229         spinlock_t all_channels_lock;
 230 };
 231
 232 /* Get the PPP protocol number from a skb */
 233 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 234
 235 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 236 #define PPP_MAX_RQLEN   32
 237
 238 /*
 239  * Maximum number of multilink fragments queued up.
 240  * This has to be large enough to cope with the maximum latency of
 241  * the slowest channel relative to the others.  Strictly it should
 242  * depend on the number of channels and their characteristics.
 243  */
 244 #define PPP_MP_MAX_QLEN 128
 245
 246 /* Multilink header bits. */
 247 #define B       0x80            /* this fragment begins a packet */
 248 #define E       0x40            /* this fragment ends a packet */
 249
 250 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 251 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 252 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 253
 254 /* Prototypes. */
 255 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 256                         struct file *file, unsigned int cmd, unsigned long arg);
 257 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
 258 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 259 static void ppp_push(struct ppp *ppp);
 260 static void ppp_channel_push(struct channel *pch);
 261 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 262                               struct channel *pch);
 263 static void ppp_receive_error(struct ppp *ppp);
 264 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 265 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 266                                             struct sk_buff *skb);
 267 #ifdef CONFIG_PPP_MULTILINK
 268 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 269                                 struct channel *pch);
 270 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 271 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 272 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 273 #endif /* CONFIG_PPP_MULTILINK */
 274 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
 275 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 276 static void ppp_ccp_closed(struct ppp *ppp);
 277 static struct compressor *find_compressor(int type);
 278 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 279 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
 280 static void init_ppp_file(struct ppp_file *pf, int kind);
 281 static void ppp_destroy_interface(struct ppp *ppp);
 282 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 283 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 284 static int ppp_connect_channel(struct channel *pch, int unit);
 285 static int ppp_disconnect_channel(struct channel *pch);
 286 static void ppp_destroy_channel(struct channel *pch);
 287 static int unit_get(struct idr *p, void *ptr, int min);
 288 static int unit_set(struct idr *p, void *ptr, int n);
 289 static void unit_put(struct idr *p, int n);
 290 static void *unit_find(struct idr *p, int n);
 291 static void ppp_setup(struct net_device *dev);
 292
 293 static const struct net_device_ops ppp_netdev_ops;
 294
 295 static struct class *ppp_class;
 296
 297 /* per net-namespace data */
 298 static inline struct ppp_net *ppp_pernet(struct net *net)
 299 {
 300         return net_generic(net, ppp_net_id);
 301 }
 302
 303 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 304 static inline int proto_to_npindex(int proto)
 305 {
 306         switch (proto) {
 307         case PPP_IP:
 308                 return NP_IP;
 309         case PPP_IPV6:
 310                 return NP_IPV6;
 311         case PPP_IPX:
 312                 return NP_IPX;
 313         case PPP_AT:
 314                 return NP_AT;
 315         case PPP_MPLS_UC:
 316                 return NP_MPLS_UC;
 317         case PPP_MPLS_MC:
 318                 return NP_MPLS_MC;
 319         }
 320         return -EINVAL;
 321 }
 322
 323 /* Translates an NP index into a PPP protocol number */
 324 static const int npindex_to_proto[NUM_NP] = {
 325         PPP_IP,
 326         PPP_IPV6,
 327         PPP_IPX,
 328         PPP_AT,
 329         PPP_MPLS_UC,
 330         PPP_MPLS_MC,
 331 };
 332
 333 /* Translates an ethertype into an NP index */
 334 static inline int ethertype_to_npindex(int ethertype)
 335 {
 336         switch (ethertype) {
 337         case ETH_P_IP:
 338                 return NP_IP;
 339         case ETH_P_IPV6:
 340                 return NP_IPV6;
 341         case ETH_P_IPX:
 342                 return NP_IPX;
 343         case ETH_P_PPPTALK:
 344         case ETH_P_ATALK:
 345                 return NP_AT;
 346         case ETH_P_MPLS_UC:
 347                 return NP_MPLS_UC;
 348         case ETH_P_MPLS_MC:
 349                 return NP_MPLS_MC;
 350         }
 351         return -1;
 352 }
 353
 354 /* Translates an NP index into an ethertype */
 355 static const int npindex_to_ethertype[NUM_NP] = {
 356         ETH_P_IP,
 357         ETH_P_IPV6,
 358         ETH_P_IPX,
 359         ETH_P_PPPTALK,
 360         ETH_P_MPLS_UC,
 361         ETH_P_MPLS_MC,
 362 };
 363
 364 /*
 365  * Locking shorthand.
 366  */
 367 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 368 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 369 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 370 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 371 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 372                                      ppp_recv_lock(ppp); } while (0)
 373 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 374                                      ppp_xmit_unlock(ppp); } while (0)
 375
 376 /*
 377  * /dev/ppp device routines.
 378  * The /dev/ppp device is used by pppd to control the ppp unit.
 379  * It supports the read, write, ioctl and poll functions.
 380  * Open instances of /dev/ppp can be in one of three states:
 381  * unattached, attached to a ppp unit, or attached to a ppp channel.
 382  */
 383 static int ppp_open(struct inode *inode, struct file *file)
 384 {
 385         /*
 386          * This could (should?) be enforced by the permissions on /dev/ppp.
 387          */
 388         if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
 389                 return -EPERM;
 390         return 0;
 391 }
 392
 393 static int ppp_release(struct inode *unused, struct file *file)
 394 {
 395         struct ppp_file *pf = file->private_data;
 396         struct ppp *ppp;
 397
 398         if (pf) {
 399                 file->private_data = NULL;
 400                 if (pf->kind == INTERFACE) {
 401                         ppp = PF_TO_PPP(pf);
 402                         rtnl_lock();
 403                         if (file == ppp->owner)
 404                                 unregister_netdevice(ppp->dev);
 405                         rtnl_unlock();
 406                 }
 407                 if (refcount_dec_and_test(&pf->refcnt)) {
 408                         switch (pf->kind) {
 409                         case INTERFACE:
 410                                 ppp_destroy_interface(PF_TO_PPP(pf));
 411                                 break;
 412                         case CHANNEL:
 413                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 414                                 break;
 415                         }
 416                 }
 417         }
 418         return 0;
 419 }
 420
 421 static ssize_t ppp_read(struct file *file, char __user *buf,
 422                         size_t count, loff_t *ppos)
 423 {
 424         struct ppp_file *pf = file->private_data;
 425         DECLARE_WAITQUEUE(wait, current);
 426         ssize_t ret;
 427         struct sk_buff *skb = NULL;
 428         struct iovec iov;
 429         struct iov_iter to;
 430
 431         ret = count;
 432
 433         if (!pf)
 434                 return -ENXIO;
 435         add_wait_queue(&pf->rwait, &wait);
 436         for (;;) {
 437                 set_current_state(TASK_INTERRUPTIBLE);
 438                 skb = skb_dequeue(&pf->rq);
 439                 if (skb)
 440                         break;
 441                 ret = 0;
 442                 if (pf->dead)
 443                         break;
 444                 if (pf->kind == INTERFACE) {
 445                         /*
 446                          * Return 0 (EOF) on an interface that has no
 447                          * channels connected, unless it is looping
 448                          * network traffic (demand mode).
 449                          */
 450                         struct ppp *ppp = PF_TO_PPP(pf);
 451
 452                         ppp_recv_lock(ppp);
 453                         if (ppp->n_channels == 0 &&
 454                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
 455                                 ppp_recv_unlock(ppp);
 456                                 break;
 457                         }
 458                         ppp_recv_unlock(ppp);
 459                 }
 460                 ret = -EAGAIN;
 461                 if (file->f_flags & O_NONBLOCK)
 462                         break;
 463                 ret = -ERESTARTSYS;
 464                 if (signal_pending(current))
 465                         break;
 466                 schedule();
 467         }
 468         set_current_state(TASK_RUNNING);
 469         remove_wait_queue(&pf->rwait, &wait);
 470
 471         if (!skb)
 472                 goto out;
 473
 474         ret = -EOVERFLOW;
 475         if (skb->len > count)
 476                 goto outf;
 477         ret = -EFAULT;
 478         iov.iov_base = buf;
 479         iov.iov_len = count;
 480         iov_iter_init(&to, READ, &iov, 1, count);
 481         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 482                 goto outf;
 483         ret = skb->len;
 484
 485  outf:
 486         kfree_skb(skb);
 487  out:
 488         return ret;
 489 }
 490
 491 static ssize_t ppp_write(struct file *file, const char __user *buf,
 492                          size_t count, loff_t *ppos)
 493 {
 494         struct ppp_file *pf = file->private_data;
 495         struct sk_buff *skb;
 496         ssize_t ret;
 497
 498         if (!pf)
 499                 return -ENXIO;
 500         ret = -ENOMEM;
 501         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 502         if (!skb)
 503                 goto out;
 504         skb_reserve(skb, pf->hdrlen);
 505         ret = -EFAULT;
 506         if (copy_from_user(skb_put(skb, count), buf, count)) {
 507                 kfree_skb(skb);
 508                 goto out;
 509         }
 510
 511         switch (pf->kind) {
 512         case INTERFACE:
 513                 ppp_xmit_process(PF_TO_PPP(pf), skb);
 514                 break;
 515         case CHANNEL:
 516                 skb_queue_tail(&pf->xq, skb);
 517                 ppp_channel_push(PF_TO_CHANNEL(pf));
 518                 break;
 519         }
 520
 521         ret = count;
 522
 523  out:
 524         return ret;
 525 }
 526
 527 /* No kernel lock - fine */
 528 static __poll_t ppp_poll(struct file *file, poll_table *wait)
 529 {
 530         struct ppp_file *pf = file->private_data;
 531         __poll_t mask;
 532
 533         if (!pf)
 534                 return 0;
 535         poll_wait(file, &pf->rwait, wait);
 536         mask = EPOLLOUT | EPOLLWRNORM;
 537         if (skb_peek(&pf->rq))
 538                 mask |= EPOLLIN | EPOLLRDNORM;
 539         if (pf->dead)
 540                 mask |= EPOLLHUP;
 541         else if (pf->kind == INTERFACE) {
 542                 /* see comment in ppp_read */
 543                 struct ppp *ppp = PF_TO_PPP(pf);
 544
 545                 ppp_recv_lock(ppp);
 546                 if (ppp->n_channels == 0 &&
 547                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 548                         mask |= EPOLLIN | EPOLLRDNORM;
 549                 ppp_recv_unlock(ppp);
 550         }
 551
 552         return mask;
 553 }
 554
 555 #ifdef CONFIG_PPP_FILTER
 556 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
 557 {
 558         struct sock_fprog_kern fprog;
 559         struct bpf_prog *res = NULL;
 560         int err;
 561
 562         if (!uprog->len)
 563                 return NULL;
 564
 565         /* uprog->len is unsigned short, so no overflow here */
 566         fprog.len = uprog->len;
 567         fprog.filter = memdup_user(uprog->filter,
 568                                    uprog->len * sizeof(struct sock_filter));
 569         if (IS_ERR(fprog.filter))
 570                 return ERR_CAST(fprog.filter);
 571
 572         err = bpf_prog_create(&res, &fprog);
 573         kfree(fprog.filter);
 574
 575         return err ? ERR_PTR(err) : res;
 576 }
 577
 578 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
 579 {
 580         struct sock_fprog uprog;
 581
 582         if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
 583                 return ERR_PTR(-EFAULT);
 584         return get_filter(&uprog);
 585 }
 586
 587 #ifdef CONFIG_COMPAT
 588 struct sock_fprog32 {
 589         unsigned short len;
 590         compat_caddr_t filter;
 591 };
 592
 593 #define PPPIOCSPASS32           _IOW('t', 71, struct sock_fprog32)
 594 #define PPPIOCSACTIVE32         _IOW('t', 70, struct sock_fprog32)
 595
 596 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
 597 {
 598         struct sock_fprog32 uprog32;
 599         struct sock_fprog uprog;
 600
 601         if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
 602                 return ERR_PTR(-EFAULT);
 603         uprog.len = uprog32.len;
 604         uprog.filter = compat_ptr(uprog32.filter);
 605         return get_filter(&uprog);
 606 }
 607 #endif
 608 #endif
 609
 610 /* Bridge one PPP channel to another.
 611  * When two channels are bridged, ppp_input on one channel is redirected to
 612  * the other's ops->start_xmit handler.
 613  * In order to safely bridge channels we must reject channels which are already
 614  * part of a bridge instance, or which form part of an existing unit.
 615  * Once successfully bridged, each channel holds a reference on the other
 616  * to prevent it being freed while the bridge is extant.
 617  */
 618 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
 619 {
 620         write_lock_bh(&pch->upl);
 621         if (pch->ppp ||
 622             rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
 623                 write_unlock_bh(&pch->upl);
 624                 return -EALREADY;
 625         }
 626         refcount_inc(&pchb->file.refcnt);
 627         rcu_assign_pointer(pch->bridge, pchb);
 628         write_unlock_bh(&pch->upl);
 629
 630         write_lock_bh(&pchb->upl);
 631         if (pchb->ppp ||
 632             rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
 633                 write_unlock_bh(&pchb->upl);
 634                 goto err_unset;
 635         }
 636         refcount_inc(&pch->file.refcnt);
 637         rcu_assign_pointer(pchb->bridge, pch);
 638         write_unlock_bh(&pchb->upl);
 639
 640         return 0;
 641
 642 err_unset:
 643         write_lock_bh(&pch->upl);
 644         /* Re-read pch->bridge with upl held in case it was modified concurrently */
 645         pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
 646         RCU_INIT_POINTER(pch->bridge, NULL);
 647         write_unlock_bh(&pch->upl);
 648         synchronize_rcu();
 649
 650         if (pchb)
 651                 if (refcount_dec_and_test(&pchb->file.refcnt))
 652                         ppp_destroy_channel(pchb);
 653
 654         return -EALREADY;
 655 }
 656
 657 static int ppp_unbridge_channels(struct channel *pch)
 658 {
 659         struct channel *pchb, *pchbb;
 660
 661         write_lock_bh(&pch->upl);
 662         pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
 663         if (!pchb) {
 664                 write_unlock_bh(&pch->upl);
 665                 return -EINVAL;
 666         }
 667         RCU_INIT_POINTER(pch->bridge, NULL);
 668         write_unlock_bh(&pch->upl);
 669
 670         /* Only modify pchb if phcb->bridge points back to pch.
 671          * If not, it implies that there has been a race unbridging (and possibly
 672          * even rebridging) pchb.  We should leave pchb alone to avoid either a
 673          * refcount underflow, or breaking another established bridge instance.
 674          */
 675         write_lock_bh(&pchb->upl);
 676         pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
 677         if (pchbb == pch)
 678                 RCU_INIT_POINTER(pchb->bridge, NULL);
 679         write_unlock_bh(&pchb->upl);
 680
 681         synchronize_rcu();
 682
 683         if (pchbb == pch)
 684                 if (refcount_dec_and_test(&pch->file.refcnt))
 685                         ppp_destroy_channel(pch);
 686
 687         if (refcount_dec_and_test(&pchb->file.refcnt))
 688                 ppp_destroy_channel(pchb);
 689
 690         return 0;
 691 }
 692
 693 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 694 {
 695         struct ppp_file *pf;
 696         struct ppp *ppp;
 697         int err = -EFAULT, val, val2, i;
 698         struct ppp_idle32 idle32;
 699         struct ppp_idle64 idle64;
 700         struct npioctl npi;
 701         int unit, cflags;
 702         struct slcompress *vj;
 703         void __user *argp = (void __user *)arg;
 704         int __user *p = argp;
 705
 706         mutex_lock(&ppp_mutex);
 707
 708         pf = file->private_data;
 709         if (!pf) {
 710                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 711                                            pf, file, cmd, arg);
 712                 goto out;
 713         }
 714
 715         if (cmd == PPPIOCDETACH) {
 716                 /*
 717                  * PPPIOCDETACH is no longer supported as it was heavily broken,
 718                  * and is only known to have been used by pppd older than
 719                  * ppp-2.4.2 (released November 2003).
 720                  */
 721                 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
 722                              current->comm, current->pid);
 723                 err = -EINVAL;
 724                 goto out;
 725         }
 726
 727         if (pf->kind == CHANNEL) {
 728                 struct channel *pch, *pchb;
 729                 struct ppp_channel *chan;
 730                 struct ppp_net *pn;
 731
 732                 pch = PF_TO_CHANNEL(pf);
 733
 734                 switch (cmd) {
 735                 case PPPIOCCONNECT:
 736                         if (get_user(unit, p))
 737                                 break;
 738                         err = ppp_connect_channel(pch, unit);
 739                         break;
 740
 741                 case PPPIOCDISCONN:
 742                         err = ppp_disconnect_channel(pch);
 743                         break;
 744
 745                 case PPPIOCBRIDGECHAN:
 746                         if (get_user(unit, p))
 747                                 break;
 748                         err = -ENXIO;
 749                         pn = ppp_pernet(current->nsproxy->net_ns);
 750                         spin_lock_bh(&pn->all_channels_lock);
 751                         pchb = ppp_find_channel(pn, unit);
 752                         /* Hold a reference to prevent pchb being freed while
 753                          * we establish the bridge.
 754                          */
 755                         if (pchb)
 756                                 refcount_inc(&pchb->file.refcnt);
 757                         spin_unlock_bh(&pn->all_channels_lock);
 758                         if (!pchb)
 759                                 break;
 760                         err = ppp_bridge_channels(pch, pchb);
 761                         /* Drop earlier refcount now bridge establishment is complete */
 762                         if (refcount_dec_and_test(&pchb->file.refcnt))
 763                                 ppp_destroy_channel(pchb);
 764                         break;
 765
 766                 case PPPIOCUNBRIDGECHAN:
 767                         err = ppp_unbridge_channels(pch);
 768                         break;
 769
 770                 default:
 771                         down_read(&pch->chan_sem);
 772                         chan = pch->chan;
 773                         err = -ENOTTY;
 774                         if (chan && chan->ops->ioctl)
 775                                 err = chan->ops->ioctl(chan, cmd, arg);
 776                         up_read(&pch->chan_sem);
 777                 }
 778                 goto out;
 779         }
 780
 781         if (pf->kind != INTERFACE) {
 782                 /* can't happen */
 783                 pr_err("PPP: not interface or channel??\n");
 784                 err = -EINVAL;
 785                 goto out;
 786         }
 787
 788         ppp = PF_TO_PPP(pf);
 789         switch (cmd) {
 790         case PPPIOCSMRU:
 791                 if (get_user(val, p))
 792                         break;
 793                 ppp->mru = val;
 794                 err = 0;
 795                 break;
 796
 797         case PPPIOCSFLAGS:
 798                 if (get_user(val, p))
 799                         break;
 800                 ppp_lock(ppp);
 801                 cflags = ppp->flags & ~val;
 802 #ifdef CONFIG_PPP_MULTILINK
 803                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
 804                         ppp->nextseq = 0;
 805 #endif
 806                 ppp->flags = val & SC_FLAG_BITS;
 807                 ppp_unlock(ppp);
 808                 if (cflags & SC_CCP_OPEN)
 809                         ppp_ccp_closed(ppp);
 810                 err = 0;
 811                 break;
 812
 813         case PPPIOCGFLAGS:
 814                 val = ppp->flags | ppp->xstate | ppp->rstate;
 815                 if (put_user(val, p))
 816                         break;
 817                 err = 0;
 818                 break;
 819
 820         case PPPIOCSCOMPRESS:
 821         {
 822                 struct ppp_option_data data;
 823                 if (copy_from_user(&data, argp, sizeof(data)))
 824                         err = -EFAULT;
 825                 else
 826                         err = ppp_set_compress(ppp, &data);
 827                 break;
 828         }
 829         case PPPIOCGUNIT:
 830                 if (put_user(ppp->file.index, p))
 831                         break;
 832                 err = 0;
 833                 break;
 834
 835         case PPPIOCSDEBUG:
 836                 if (get_user(val, p))
 837                         break;
 838                 ppp->debug = val;
 839                 err = 0;
 840                 break;
 841
 842         case PPPIOCGDEBUG:
 843                 if (put_user(ppp->debug, p))
 844                         break;
 845                 err = 0;
 846                 break;
 847
 848         case PPPIOCGIDLE32:
 849                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 850                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
 851                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
 852                         break;
 853                 err = 0;
 854                 break;
 855
 856         case PPPIOCGIDLE64:
 857                 idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 858                 idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
 859                 if (copy_to_user(argp, &idle64, sizeof(idle64)))
 860                         break;
 861                 err = 0;
 862                 break;
 863
 864         case PPPIOCSMAXCID:
 865                 if (get_user(val, p))
 866                         break;
 867                 val2 = 15;
 868                 if ((val >> 16) != 0) {
 869                         val2 = val >> 16;
 870                         val &= 0xffff;
 871                 }
 872                 vj = slhc_init(val2+1, val+1);
 873                 if (IS_ERR(vj)) {
 874                         err = PTR_ERR(vj);
 875                         break;
 876                 }
 877                 ppp_lock(ppp);
 878                 if (ppp->vj)
 879                         slhc_free(ppp->vj);
 880                 ppp->vj = vj;
 881                 ppp_unlock(ppp);
 882                 err = 0;
 883                 break;
 884
 885         case PPPIOCGNPMODE:
 886         case PPPIOCSNPMODE:
 887                 if (copy_from_user(&npi, argp, sizeof(npi)))
 888                         break;
 889                 err = proto_to_npindex(npi.protocol);
 890                 if (err < 0)
 891                         break;
 892                 i = err;
 893                 if (cmd == PPPIOCGNPMODE) {
 894                         err = -EFAULT;
 895                         npi.mode = ppp->npmode[i];
 896                         if (copy_to_user(argp, &npi, sizeof(npi)))
 897                                 break;
 898                 } else {
 899                         ppp->npmode[i] = npi.mode;
 900                         /* we may be able to transmit more packets now (??) */
 901                         netif_wake_queue(ppp->dev);
 902                 }
 903                 err = 0;
 904                 break;
 905
 906 #ifdef CONFIG_PPP_FILTER
 907         case PPPIOCSPASS:
 908         case PPPIOCSACTIVE:
 909         {
 910                 struct bpf_prog *filter = ppp_get_filter(argp);
 911                 struct bpf_prog **which;
 912
 913                 if (IS_ERR(filter)) {
 914                         err = PTR_ERR(filter);
 915                         break;
 916                 }
 917                 if (cmd == PPPIOCSPASS)
 918                         which = &ppp->pass_filter;
 919                 else
 920                         which = &ppp->active_filter;
 921                 ppp_lock(ppp);
 922                 if (*which)
 923                         bpf_prog_destroy(*which);
 924                 *which = filter;
 925                 ppp_unlock(ppp);
 926                 err = 0;
 927                 break;
 928         }
 929 #endif /* CONFIG_PPP_FILTER */
 930
 931 #ifdef CONFIG_PPP_MULTILINK
 932         case PPPIOCSMRRU:
 933                 if (get_user(val, p))
 934                         break;
 935                 ppp_recv_lock(ppp);
 936                 ppp->mrru = val;
 937                 ppp_recv_unlock(ppp);
 938                 err = 0;
 939                 break;
 940 #endif /* CONFIG_PPP_MULTILINK */
 941
 942         default:
 943                 err = -ENOTTY;
 944         }
 945
 946 out:
 947         mutex_unlock(&ppp_mutex);
 948
 949         return err;
 950 }
 951
 952 #ifdef CONFIG_COMPAT
 953 struct ppp_option_data32 {
 954         compat_uptr_t           ptr;
 955         u32                     length;
 956         compat_int_t            transmit;
 957 };
 958 #define PPPIOCSCOMPRESS32       _IOW('t', 77, struct ppp_option_data32)
 959
 960 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 961 {
 962         struct ppp_file *pf;
 963         int err = -ENOIOCTLCMD;
 964         void __user *argp = (void __user *)arg;
 965
 966         mutex_lock(&ppp_mutex);
 967
 968         pf = file->private_data;
 969         if (pf && pf->kind == INTERFACE) {
 970                 struct ppp *ppp = PF_TO_PPP(pf);
 971                 switch (cmd) {
 972 #ifdef CONFIG_PPP_FILTER
 973                 case PPPIOCSPASS32:
 974                 case PPPIOCSACTIVE32:
 975                 {
 976                         struct bpf_prog *filter = compat_ppp_get_filter(argp);
 977                         struct bpf_prog **which;
 978
 979                         if (IS_ERR(filter)) {
 980                                 err = PTR_ERR(filter);
 981                                 break;
 982                         }
 983                         if (cmd == PPPIOCSPASS32)
 984                                 which = &ppp->pass_filter;
 985                         else
 986                                 which = &ppp->active_filter;
 987                         ppp_lock(ppp);
 988                         if (*which)
 989                                 bpf_prog_destroy(*which);
 990                         *which = filter;
 991                         ppp_unlock(ppp);
 992                         err = 0;
 993                         break;
 994                 }
 995 #endif /* CONFIG_PPP_FILTER */
 996                 case PPPIOCSCOMPRESS32:
 997                 {
 998                         struct ppp_option_data32 data32;
 999                         if (copy_from_user(&data32, argp, sizeof(data32))) {
1000                                 err = -EFAULT;
1001                         } else {
1002                                 struct ppp_option_data data = {
1003                                         .ptr = compat_ptr(data32.ptr),
1004                                         .length = data32.length,
1005                                         .transmit = data32.transmit
1006                                 };
1007                                 err = ppp_set_compress(ppp, &data);
1008                         }
1009                         break;
1010                 }
1011                 }
1012         }
1013         mutex_unlock(&ppp_mutex);
1014
1015         /* all other commands have compatible arguments */
1016         if (err == -ENOIOCTLCMD)
1017                 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1018
1019         return err;
1020 }
1021 #endif
1022
1023 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1024                         struct file *file, unsigned int cmd, unsigned long arg)
1025 {
1026         int unit, err = -EFAULT;
1027         struct ppp *ppp;
1028         struct channel *chan;
1029         struct ppp_net *pn;
1030         int __user *p = (int __user *)arg;
1031
1032         switch (cmd) {
1033         case PPPIOCNEWUNIT:
1034                 /* Create a new ppp unit */
1035                 if (get_user(unit, p))
1036                         break;
1037                 err = ppp_create_interface(net, file, &unit);
1038                 if (err < 0)
1039                         break;
1040
1041                 err = -EFAULT;
1042                 if (put_user(unit, p))
1043                         break;
1044                 err = 0;
1045                 break;
1046
1047         case PPPIOCATTACH:
1048                 /* Attach to an existing ppp unit */
1049                 if (get_user(unit, p))
1050                         break;
1051                 err = -ENXIO;
1052                 pn = ppp_pernet(net);
1053                 mutex_lock(&pn->all_ppp_mutex);
1054                 ppp = ppp_find_unit(pn, unit);
1055                 if (ppp) {
1056                         refcount_inc(&ppp->file.refcnt);
1057                         file->private_data = &ppp->file;
1058                         err = 0;
1059                 }
1060                 mutex_unlock(&pn->all_ppp_mutex);
1061                 break;
1062
1063         case PPPIOCATTCHAN:
1064                 if (get_user(unit, p))
1065                         break;
1066                 err = -ENXIO;
1067                 pn = ppp_pernet(net);
1068                 spin_lock_bh(&pn->all_channels_lock);
1069                 chan = ppp_find_channel(pn, unit);
1070                 if (chan) {
1071                         refcount_inc(&chan->file.refcnt);
1072                         file->private_data = &chan->file;
1073                         err = 0;
1074                 }
1075                 spin_unlock_bh(&pn->all_channels_lock);
1076                 break;
1077
1078         default:
1079                 err = -ENOTTY;
1080         }
1081
1082         return err;
1083 }
1084
1085 static const struct file_operations ppp_device_fops = {
1086         .owner          = THIS_MODULE,
1087         .read           = ppp_read,
1088         .write          = ppp_write,
1089         .poll           = ppp_poll,
1090         .unlocked_ioctl = ppp_ioctl,
1091 #ifdef CONFIG_COMPAT
1092         .compat_ioctl   = ppp_compat_ioctl,
1093 #endif
1094         .open           = ppp_open,
1095         .release        = ppp_release,
1096         .llseek         = noop_llseek,
1097 };
1098
1099 static __net_init int ppp_init_net(struct net *net)
1100 {
1101         struct ppp_net *pn = net_generic(net, ppp_net_id);
1102
1103         idr_init(&pn->units_idr);
1104         mutex_init(&pn->all_ppp_mutex);
1105
1106         INIT_LIST_HEAD(&pn->all_channels);
1107         INIT_LIST_HEAD(&pn->new_channels);
1108
1109         spin_lock_init(&pn->all_channels_lock);
1110
1111         return 0;
1112 }
1113
1114 static __net_exit void ppp_exit_net(struct net *net)
1115 {
1116         struct ppp_net *pn = net_generic(net, ppp_net_id);
1117         struct net_device *dev;
1118         struct net_device *aux;
1119         struct ppp *ppp;
1120         LIST_HEAD(list);
1121         int id;
1122
1123         rtnl_lock();
1124         for_each_netdev_safe(net, dev, aux) {
1125                 if (dev->netdev_ops == &ppp_netdev_ops)
1126                         unregister_netdevice_queue(dev, &list);
1127         }
1128
1129         idr_for_each_entry(&pn->units_idr, ppp, id)
1130                 /* Skip devices already unregistered by previous loop */
1131                 if (!net_eq(dev_net(ppp->dev), net))
1132                         unregister_netdevice_queue(ppp->dev, &list);
1133
1134         unregister_netdevice_many(&list);
1135         rtnl_unlock();
1136
1137         mutex_destroy(&pn->all_ppp_mutex);
1138         idr_destroy(&pn->units_idr);
1139         WARN_ON_ONCE(!list_empty(&pn->all_channels));
1140         WARN_ON_ONCE(!list_empty(&pn->new_channels));
1141 }
1142
1143 static struct pernet_operations ppp_net_ops = {
1144         .init = ppp_init_net,
1145         .exit = ppp_exit_net,
1146         .id   = &ppp_net_id,
1147         .size = sizeof(struct ppp_net),
1148 };
1149
1150 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1151 {
1152         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1153         int ret;
1154
1155         mutex_lock(&pn->all_ppp_mutex);
1156
1157         if (unit < 0) {
1158                 ret = unit_get(&pn->units_idr, ppp, 0);
1159                 if (ret < 0)
1160                         goto err;
1161                 if (!ifname_is_set) {
1162                         while (1) {
1163                                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1164                                 if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
1165                                         break;
1166                                 unit_put(&pn->units_idr, ret);
1167                                 ret = unit_get(&pn->units_idr, ppp, ret + 1);
1168                                 if (ret < 0)
1169                                         goto err;
1170                         }
1171                 }
1172         } else {
1173                 /* Caller asked for a specific unit number. Fail with -EEXIST
1174                  * if unavailable. For backward compatibility, return -EEXIST
1175                  * too if idr allocation fails; this makes pppd retry without
1176                  * requesting a specific unit number.
1177                  */
1178                 if (unit_find(&pn->units_idr, unit)) {
1179                         ret = -EEXIST;
1180                         goto err;
1181                 }
1182                 ret = unit_set(&pn->units_idr, ppp, unit);
1183                 if (ret < 0) {
1184                         /* Rewrite error for backward compatibility */
1185                         ret = -EEXIST;
1186                         goto err;
1187                 }
1188         }
1189         ppp->file.index = ret;
1190
1191         if (!ifname_is_set)
1192                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1193
1194         mutex_unlock(&pn->all_ppp_mutex);
1195
1196         ret = register_netdevice(ppp->dev);
1197         if (ret < 0)
1198                 goto err_unit;
1199
1200         atomic_inc(&ppp_unit_count);
1201
1202         return 0;
1203
1204 err_unit:
1205         mutex_lock(&pn->all_ppp_mutex);
1206         unit_put(&pn->units_idr, ppp->file.index);
1207 err:
1208         mutex_unlock(&pn->all_ppp_mutex);
1209
1210         return ret;
1211 }
1212
1213 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1214                              const struct ppp_config *conf)
1215 {
1216         struct ppp *ppp = netdev_priv(dev);
1217         int indx;
1218         int err;
1219         int cpu;
1220
1221         ppp->dev = dev;
1222         ppp->ppp_net = src_net;
1223         ppp->mru = PPP_MRU;
1224         ppp->owner = conf->file;
1225
1226         init_ppp_file(&ppp->file, INTERFACE);
1227         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1228
1229         for (indx = 0; indx < NUM_NP; ++indx)
1230                 ppp->npmode[indx] = NPMODE_PASS;
1231         INIT_LIST_HEAD(&ppp->channels);
1232         spin_lock_init(&ppp->rlock);
1233         spin_lock_init(&ppp->wlock);
1234
1235         ppp->xmit_recursion = alloc_percpu(int);
1236         if (!ppp->xmit_recursion) {
1237                 err = -ENOMEM;
1238                 goto err1;
1239         }
1240         for_each_possible_cpu(cpu)
1241                 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1242
1243 #ifdef CONFIG_PPP_MULTILINK
1244         ppp->minseq = -1;
1245         skb_queue_head_init(&ppp->mrq);
1246 #endif /* CONFIG_PPP_MULTILINK */
1247 #ifdef CONFIG_PPP_FILTER
1248         ppp->pass_filter = NULL;
1249         ppp->active_filter = NULL;
1250 #endif /* CONFIG_PPP_FILTER */
1251
1252         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1253         if (err < 0)
1254                 goto err2;
1255
1256         conf->file->private_data = &ppp->file;
1257
1258         return 0;
1259 err2:
1260         free_percpu(ppp->xmit_recursion);
1261 err1:
1262         return err;
1263 }
1264
1265 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1266         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1267 };
1268
1269 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1270                            struct netlink_ext_ack *extack)
1271 {
1272         if (!data)
1273                 return -EINVAL;
1274
1275         if (!data[IFLA_PPP_DEV_FD])
1276                 return -EINVAL;
1277         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1278                 return -EBADF;
1279
1280         return 0;
1281 }
1282
1283 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1284                           struct nlattr *tb[], struct nlattr *data[],
1285                           struct netlink_ext_ack *extack)
1286 {
1287         struct ppp_config conf = {
1288                 .unit = -1,
1289                 .ifname_is_set = true,
1290         };
1291         struct file *file;
1292         int err;
1293
1294         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1295         if (!file)
1296                 return -EBADF;
1297
1298         /* rtnl_lock is already held here, but ppp_create_interface() locks
1299          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1300          * possible deadlock due to lock order inversion, at the cost of
1301          * pushing the problem back to userspace.
1302          */
1303         if (!mutex_trylock(&ppp_mutex)) {
1304                 err = -EBUSY;
1305                 goto out;
1306         }
1307
1308         if (file->f_op != &ppp_device_fops || file->private_data) {
1309                 err = -EBADF;
1310                 goto out_unlock;
1311         }
1312
1313         conf.file = file;
1314
1315         /* Don't use device name generated by the rtnetlink layer when ifname
1316          * isn't specified. Let ppp_dev_configure() set the device name using
1317          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1318          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1319          */
1320         if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1321                 conf.ifname_is_set = false;
1322
1323         err = ppp_dev_configure(src_net, dev, &conf);
1324
1325 out_unlock:
1326         mutex_unlock(&ppp_mutex);
1327 out:
1328         fput(file);
1329
1330         return err;
1331 }
1332
1333 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1334 {
1335         unregister_netdevice_queue(dev, head);
1336 }
1337
1338 static size_t ppp_nl_get_size(const struct net_device *dev)
1339 {
1340         return 0;
1341 }
1342
1343 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1344 {
1345         return 0;
1346 }
1347
1348 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1349 {
1350         struct ppp *ppp = netdev_priv(dev);
1351
1352         return ppp->ppp_net;
1353 }
1354
1355 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1356         .kind           = "ppp",
1357         .maxtype        = IFLA_PPP_MAX,
1358         .policy         = ppp_nl_policy,
1359         .priv_size      = sizeof(struct ppp),
1360         .setup          = ppp_setup,
1361         .validate       = ppp_nl_validate,
1362         .newlink        = ppp_nl_newlink,
1363         .dellink        = ppp_nl_dellink,
1364         .get_size       = ppp_nl_get_size,
1365         .fill_info      = ppp_nl_fill_info,
1366         .get_link_net   = ppp_nl_get_link_net,
1367 };
1368
1369 #define PPP_MAJOR       108
1370
1371 /* Called at boot time if ppp is compiled into the kernel,
1372    or at module load time (from init_module) if compiled as a module. */
1373 static int __init ppp_init(void)
1374 {
1375         int err;
1376
1377         pr_info("PPP generic driver version " PPP_VERSION "\n");
1378
1379         err = register_pernet_device(&ppp_net_ops);
1380         if (err) {
1381                 pr_err("failed to register PPP pernet device (%d)\n", err);
1382                 goto out;
1383         }
1384
1385         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1386         if (err) {
1387                 pr_err("failed to register PPP device (%d)\n", err);
1388                 goto out_net;
1389         }
1390
1391         ppp_class = class_create(THIS_MODULE, "ppp");
1392         if (IS_ERR(ppp_class)) {
1393                 err = PTR_ERR(ppp_class);
1394                 goto out_chrdev;
1395         }
1396
1397         err = rtnl_link_register(&ppp_link_ops);
1398         if (err) {
1399                 pr_err("failed to register rtnetlink PPP handler\n");
1400                 goto out_class;
1401         }
1402
1403         /* not a big deal if we fail here :-) */
1404         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1405
1406         return 0;
1407
1408 out_class:
1409         class_destroy(ppp_class);
1410 out_chrdev:
1411         unregister_chrdev(PPP_MAJOR, "ppp");
1412 out_net:
1413         unregister_pernet_device(&ppp_net_ops);
1414 out:
1415         return err;
1416 }
1417
1418 /*
1419  * Network interface unit routines.
1420  */
1421 static netdev_tx_t
1422 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1423 {
1424         struct ppp *ppp = netdev_priv(dev);
1425         int npi, proto;
1426         unsigned char *pp;
1427
1428         npi = ethertype_to_npindex(ntohs(skb->protocol));
1429         if (npi < 0)
1430                 goto outf;
1431
1432         /* Drop, accept or reject the packet */
1433         switch (ppp->npmode[npi]) {
1434         case NPMODE_PASS:
1435                 break;
1436         case NPMODE_QUEUE:
1437                 /* it would be nice to have a way to tell the network
1438                    system to queue this one up for later. */
1439                 goto outf;
1440         case NPMODE_DROP:
1441         case NPMODE_ERROR:
1442                 goto outf;
1443         }
1444
1445         /* Put the 2-byte PPP protocol number on the front,
1446            making sure there is room for the address and control fields. */
1447         if (skb_cow_head(skb, PPP_HDRLEN))
1448                 goto outf;
1449
1450         pp = skb_push(skb, 2);
1451         proto = npindex_to_proto[npi];
1452         put_unaligned_be16(proto, pp);
1453
1454         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1455         ppp_xmit_process(ppp, skb);
1456
1457         return NETDEV_TX_OK;
1458
1459  outf:
1460         kfree_skb(skb);
1461         ++dev->stats.tx_dropped;
1462         return NETDEV_TX_OK;
1463 }
1464
1465 static int
1466 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1467                        void __user *addr, int cmd)
1468 {
1469         struct ppp *ppp = netdev_priv(dev);
1470         int err = -EFAULT;
1471         struct ppp_stats stats;
1472         struct ppp_comp_stats cstats;
1473         char *vers;
1474
1475         switch (cmd) {
1476         case SIOCGPPPSTATS:
1477                 ppp_get_stats(ppp, &stats);
1478                 if (copy_to_user(addr, &stats, sizeof(stats)))
1479                         break;
1480                 err = 0;
1481                 break;
1482
1483         case SIOCGPPPCSTATS:
1484                 memset(&cstats, 0, sizeof(cstats));
1485                 if (ppp->xc_state)
1486                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1487                 if (ppp->rc_state)
1488                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1489                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1490                         break;
1491                 err = 0;
1492                 break;
1493
1494         case SIOCGPPPVER:
1495                 vers = PPP_VERSION;
1496                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1497                         break;
1498                 err = 0;
1499                 break;
1500
1501         default:
1502                 err = -EINVAL;
1503         }
1504
1505         return err;
1506 }
1507
1508 static void
1509 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1510 {
1511         struct ppp *ppp = netdev_priv(dev);
1512
1513         ppp_recv_lock(ppp);
1514         stats64->rx_packets = ppp->stats64.rx_packets;
1515         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1516         ppp_recv_unlock(ppp);
1517
1518         ppp_xmit_lock(ppp);
1519         stats64->tx_packets = ppp->stats64.tx_packets;
1520         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1521         ppp_xmit_unlock(ppp);
1522
1523         stats64->rx_errors        = dev->stats.rx_errors;
1524         stats64->tx_errors        = dev->stats.tx_errors;
1525         stats64->rx_dropped       = dev->stats.rx_dropped;
1526         stats64->tx_dropped       = dev->stats.tx_dropped;
1527         stats64->rx_length_errors = dev->stats.rx_length_errors;
1528 }
1529
1530 static int ppp_dev_init(struct net_device *dev)
1531 {
1532         struct ppp *ppp;
1533
1534         netdev_lockdep_set_classes(dev);
1535
1536         ppp = netdev_priv(dev);
1537         /* Let the netdevice take a reference on the ppp file. This ensures
1538          * that ppp_destroy_interface() won't run before the device gets
1539          * unregistered.
1540          */
1541         refcount_inc(&ppp->file.refcnt);
1542
1543         return 0;
1544 }
1545
1546 static void ppp_dev_uninit(struct net_device *dev)
1547 {
1548         struct ppp *ppp = netdev_priv(dev);
1549         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1550
1551         ppp_lock(ppp);
1552         ppp->closing = 1;
1553         ppp_unlock(ppp);
1554
1555         mutex_lock(&pn->all_ppp_mutex);
1556         unit_put(&pn->units_idr, ppp->file.index);
1557         mutex_unlock(&pn->all_ppp_mutex);
1558
1559         ppp->owner = NULL;
1560
1561         ppp->file.dead = 1;
1562         wake_up_interruptible(&ppp->file.rwait);
1563 }
1564
1565 static void ppp_dev_priv_destructor(struct net_device *dev)
1566 {
1567         struct ppp *ppp;
1568
1569         ppp = netdev_priv(dev);
1570         if (refcount_dec_and_test(&ppp->file.refcnt))
1571                 ppp_destroy_interface(ppp);
1572 }
1573
1574 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1575                                  struct net_device_path *path)
1576 {
1577         struct ppp *ppp = netdev_priv(ctx->dev);
1578         struct ppp_channel *chan;
1579         struct channel *pch;
1580
1581         if (ppp->flags & SC_MULTILINK)
1582                 return -EOPNOTSUPP;
1583
1584         if (list_empty(&ppp->channels))
1585                 return -ENODEV;
1586
1587         pch = list_first_entry(&ppp->channels, struct channel, clist);
1588         chan = pch->chan;
1589         if (!chan->ops->fill_forward_path)
1590                 return -EOPNOTSUPP;
1591
1592         return chan->ops->fill_forward_path(ctx, path, chan);
1593 }
1594
1595 static const struct net_device_ops ppp_netdev_ops = {
1596         .ndo_init        = ppp_dev_init,
1597         .ndo_uninit      = ppp_dev_uninit,
1598         .ndo_start_xmit  = ppp_start_xmit,
1599         .ndo_siocdevprivate = ppp_net_siocdevprivate,
1600         .ndo_get_stats64 = ppp_get_stats64,
1601         .ndo_fill_forward_path = ppp_fill_forward_path,
1602 };
1603
1604 static struct device_type ppp_type = {
1605         .name = "ppp",
1606 };
1607
1608 static void ppp_setup(struct net_device *dev)
1609 {
1610         dev->netdev_ops = &ppp_netdev_ops;
1611         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1612
1613         dev->features |= NETIF_F_LLTX;
1614
1615         dev->hard_header_len = PPP_HDRLEN;
1616         dev->mtu = PPP_MRU;
1617         dev->addr_len = 0;
1618         dev->tx_queue_len = 3;
1619         dev->type = ARPHRD_PPP;
1620         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1621         dev->priv_destructor = ppp_dev_priv_destructor;
1622         netif_keep_dst(dev);
1623 }
1624
1625 /*
1626  * Transmit-side routines.
1627  */
1628
1629 /* Called to do any work queued up on the transmit side that can now be done */
1630 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1631 {
1632         ppp_xmit_lock(ppp);
1633         if (!ppp->closing) {
1634                 ppp_push(ppp);
1635
1636                 if (skb)
1637                         skb_queue_tail(&ppp->file.xq, skb);
1638                 while (!ppp->xmit_pending &&
1639                        (skb = skb_dequeue(&ppp->file.xq)))
1640                         ppp_send_frame(ppp, skb);
1641                 /* If there's no work left to do, tell the core net
1642                    code that we can accept some more. */
1643                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1644                         netif_wake_queue(ppp->dev);
1645                 else
1646                         netif_stop_queue(ppp->dev);
1647         } else {
1648                 kfree_skb(skb);
1649         }
1650         ppp_xmit_unlock(ppp);
1651 }
1652
1653 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1654 {
1655         local_bh_disable();
1656
1657         if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1658                 goto err;
1659
1660         (*this_cpu_ptr(ppp->xmit_recursion))++;
1661         __ppp_xmit_process(ppp, skb);
1662         (*this_cpu_ptr(ppp->xmit_recursion))--;
1663
1664         local_bh_enable();
1665
1666         return;
1667
1668 err:
1669         local_bh_enable();
1670
1671         kfree_skb(skb);
1672
1673         if (net_ratelimit())
1674                 netdev_err(ppp->dev, "recursion detected\n");
1675 }
1676
1677 static inline struct sk_buff *
1678 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1679 {
1680         struct sk_buff *new_skb;
1681         int len;
1682         int new_skb_size = ppp->dev->mtu +
1683                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1684         int compressor_skb_size = ppp->dev->mtu +
1685                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1686         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1687         if (!new_skb) {
1688                 if (net_ratelimit())
1689                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1690                 return NULL;
1691         }
1692         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1693                 skb_reserve(new_skb,
1694                             ppp->dev->hard_header_len - PPP_HDRLEN);
1695
1696         /* compressor still expects A/C bytes in hdr */
1697         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1698                                    new_skb->data, skb->len + 2,
1699                                    compressor_skb_size);
1700         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1701                 consume_skb(skb);
1702                 skb = new_skb;
1703                 skb_put(skb, len);
1704                 skb_pull(skb, 2);       /* pull off A/C bytes */
1705         } else if (len == 0) {
1706                 /* didn't compress, or CCP not up yet */
1707                 consume_skb(new_skb);
1708                 new_skb = skb;
1709         } else {
1710                 /*
1711                  * (len < 0)
1712                  * MPPE requires that we do not send unencrypted
1713                  * frames.  The compressor will return -1 if we
1714                  * should drop the frame.  We cannot simply test
1715                  * the compress_proto because MPPE and MPPC share
1716                  * the same number.
1717                  */
1718                 if (net_ratelimit())
1719                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1720                 kfree_skb(skb);
1721                 consume_skb(new_skb);
1722                 new_skb = NULL;
1723         }
1724         return new_skb;
1725 }
1726
1727 /*
1728  * Compress and send a frame.
1729  * The caller should have locked the xmit path,
1730  * and xmit_pending should be 0.
1731  */
1732 static void
1733 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1734 {
1735         int proto = PPP_PROTO(skb);
1736         struct sk_buff *new_skb;
1737         int len;
1738         unsigned char *cp;
1739
1740         if (proto < 0x8000) {
1741 #ifdef CONFIG_PPP_FILTER
1742                 /* check if we should pass this packet */
1743                 /* the filter instructions are constructed assuming
1744                    a four-byte PPP header on each packet */
1745                 *(u8 *)skb_push(skb, 2) = 1;
1746                 if (ppp->pass_filter &&
1747                     bpf_prog_run(ppp->pass_filter, skb) == 0) {
1748                         if (ppp->debug & 1)
1749                                 netdev_printk(KERN_DEBUG, ppp->dev,
1750                                               "PPP: outbound frame "
1751                                               "not passed\n");
1752                         kfree_skb(skb);
1753                         return;
1754                 }
1755                 /* if this packet passes the active filter, record the time */
1756                 if (!(ppp->active_filter &&
1757                       bpf_prog_run(ppp->active_filter, skb) == 0))
1758                         ppp->last_xmit = jiffies;
1759                 skb_pull(skb, 2);
1760 #else
1761                 /* for data packets, record the time */
1762                 ppp->last_xmit = jiffies;
1763 #endif /* CONFIG_PPP_FILTER */
1764         }
1765
1766         ++ppp->stats64.tx_packets;
1767         ppp->stats64.tx_bytes += skb->len - 2;
1768
1769         switch (proto) {
1770         case PPP_IP:
1771                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1772                         break;
1773                 /* try to do VJ TCP header compression */
1774                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1775                                     GFP_ATOMIC);
1776                 if (!new_skb) {
1777                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1778                         goto drop;
1779                 }
1780                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1781                 cp = skb->data + 2;
1782                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1783                                     new_skb->data + 2, &cp,
1784                                     !(ppp->flags & SC_NO_TCP_CCID));
1785                 if (cp == skb->data + 2) {
1786                         /* didn't compress */
1787                         consume_skb(new_skb);
1788                 } else {
1789                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1790                                 proto = PPP_VJC_COMP;
1791                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1792                         } else {
1793                                 proto = PPP_VJC_UNCOMP;
1794                                 cp[0] = skb->data[2];
1795                         }
1796                         consume_skb(skb);
1797                         skb = new_skb;
1798                         cp = skb_put(skb, len + 2);
1799                         cp[0] = 0;
1800                         cp[1] = proto;
1801                 }
1802                 break;
1803
1804         case PPP_CCP:
1805                 /* peek at outbound CCP frames */
1806                 ppp_ccp_peek(ppp, skb, 0);
1807                 break;
1808         }
1809
1810         /* try to do packet compression */
1811         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1812             proto != PPP_LCP && proto != PPP_CCP) {
1813                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1814                         if (net_ratelimit())
1815                                 netdev_err(ppp->dev,
1816                                            "ppp: compression required but "
1817                                            "down - pkt dropped.\n");
1818                         goto drop;
1819                 }
1820                 skb = pad_compress_skb(ppp, skb);
1821                 if (!skb)
1822                         goto drop;
1823         }
1824
1825         /*
1826          * If we are waiting for traffic (demand dialling),
1827          * queue it up for pppd to receive.
1828          */
1829         if (ppp->flags & SC_LOOP_TRAFFIC) {
1830                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1831                         goto drop;
1832                 skb_queue_tail(&ppp->file.rq, skb);
1833                 wake_up_interruptible(&ppp->file.rwait);
1834                 return;
1835         }
1836
1837         ppp->xmit_pending = skb;
1838         ppp_push(ppp);
1839         return;
1840
1841  drop:
1842         kfree_skb(skb);
1843         ++ppp->dev->stats.tx_errors;
1844 }
1845
1846 /*
1847  * Try to send the frame in xmit_pending.
1848  * The caller should have the xmit path locked.
1849  */
1850 static void
1851 ppp_push(struct ppp *ppp)
1852 {
1853         struct list_head *list;
1854         struct channel *pch;
1855         struct sk_buff *skb = ppp->xmit_pending;
1856
1857         if (!skb)
1858                 return;
1859
1860         list = &ppp->channels;
1861         if (list_empty(list)) {
1862                 /* nowhere to send the packet, just drop it */
1863                 ppp->xmit_pending = NULL;
1864                 kfree_skb(skb);
1865                 return;
1866         }
1867
1868         if ((ppp->flags & SC_MULTILINK) == 0) {
1869                 /* not doing multilink: send it down the first channel */
1870                 list = list->next;
1871                 pch = list_entry(list, struct channel, clist);
1872
1873                 spin_lock(&pch->downl);
1874                 if (pch->chan) {
1875                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1876                                 ppp->xmit_pending = NULL;
1877                 } else {
1878                         /* channel got unregistered */
1879                         kfree_skb(skb);
1880                         ppp->xmit_pending = NULL;
1881                 }
1882                 spin_unlock(&pch->downl);
1883                 return;
1884         }
1885
1886 #ifdef CONFIG_PPP_MULTILINK
1887         /* Multilink: fragment the packet over as many links
1888            as can take the packet at the moment. */
1889         if (!ppp_mp_explode(ppp, skb))
1890                 return;
1891 #endif /* CONFIG_PPP_MULTILINK */
1892
1893         ppp->xmit_pending = NULL;
1894         kfree_skb(skb);
1895 }
1896
1897 #ifdef CONFIG_PPP_MULTILINK
1898 static bool mp_protocol_compress __read_mostly = true;
1899 module_param(mp_protocol_compress, bool, 0644);
1900 MODULE_PARM_DESC(mp_protocol_compress,
1901                  "compress protocol id in multilink fragments");
1902
1903 /*
1904  * Divide a packet to be transmitted into fragments and
1905  * send them out the individual links.
1906  */
1907 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1908 {
1909         int len, totlen;
1910         int i, bits, hdrlen, mtu;
1911         int flen;
1912         int navail, nfree, nzero;
1913         int nbigger;
1914         int totspeed;
1915         int totfree;
1916         unsigned char *p, *q;
1917         struct list_head *list;
1918         struct channel *pch;
1919         struct sk_buff *frag;
1920         struct ppp_channel *chan;
1921
1922         totspeed = 0; /*total bitrate of the bundle*/
1923         nfree = 0; /* # channels which have no packet already queued */
1924         navail = 0; /* total # of usable channels (not deregistered) */
1925         nzero = 0; /* number of channels with zero speed associated*/
1926         totfree = 0; /*total # of channels available and
1927                                   *having no queued packets before
1928                                   *starting the fragmentation*/
1929
1930         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1931         i = 0;
1932         list_for_each_entry(pch, &ppp->channels, clist) {
1933                 if (pch->chan) {
1934                         pch->avail = 1;
1935                         navail++;
1936                         pch->speed = pch->chan->speed;
1937                 } else {
1938                         pch->avail = 0;
1939                 }
1940                 if (pch->avail) {
1941                         if (skb_queue_empty(&pch->file.xq) ||
1942                                 !pch->had_frag) {
1943                                         if (pch->speed == 0)
1944                                                 nzero++;
1945                                         else
1946                                                 totspeed += pch->speed;
1947
1948                                         pch->avail = 2;
1949                                         ++nfree;
1950                                         ++totfree;
1951                                 }
1952                         if (!pch->had_frag && i < ppp->nxchan)
1953                                 ppp->nxchan = i;
1954                 }
1955                 ++i;
1956         }
1957         /*
1958          * Don't start sending this packet unless at least half of
1959          * the channels are free.  This gives much better TCP
1960          * performance if we have a lot of channels.
1961          */
1962         if (nfree == 0 || nfree < navail / 2)
1963                 return 0; /* can't take now, leave it in xmit_pending */
1964
1965         /* Do protocol field compression */
1966         p = skb->data;
1967         len = skb->len;
1968         if (*p == 0 && mp_protocol_compress) {
1969                 ++p;
1970                 --len;
1971         }
1972
1973         totlen = len;
1974         nbigger = len % nfree;
1975
1976         /* skip to the channel after the one we last used
1977            and start at that one */
1978         list = &ppp->channels;
1979         for (i = 0; i < ppp->nxchan; ++i) {
1980                 list = list->next;
1981                 if (list == &ppp->channels) {
1982                         i = 0;
1983                         break;
1984                 }
1985         }
1986
1987         /* create a fragment for each channel */
1988         bits = B;
1989         while (len > 0) {
1990                 list = list->next;
1991                 if (list == &ppp->channels) {
1992                         i = 0;
1993                         continue;
1994                 }
1995                 pch = list_entry(list, struct channel, clist);
1996                 ++i;
1997                 if (!pch->avail)
1998                         continue;
1999
2000                 /*
2001                  * Skip this channel if it has a fragment pending already and
2002                  * we haven't given a fragment to all of the free channels.
2003                  */
2004                 if (pch->avail == 1) {
2005                         if (nfree > 0)
2006                                 continue;
2007                 } else {
2008                         pch->avail = 1;
2009                 }
2010
2011                 /* check the channel's mtu and whether it is still attached. */
2012                 spin_lock(&pch->downl);
2013                 if (pch->chan == NULL) {
2014                         /* can't use this channel, it's being deregistered */
2015                         if (pch->speed == 0)
2016                                 nzero--;
2017                         else
2018                                 totspeed -= pch->speed;
2019
2020                         spin_unlock(&pch->downl);
2021                         pch->avail = 0;
2022                         totlen = len;
2023                         totfree--;
2024                         nfree--;
2025                         if (--navail == 0)
2026                                 break;
2027                         continue;
2028                 }
2029
2030                 /*
2031                 *if the channel speed is not set divide
2032                 *the packet evenly among the free channels;
2033                 *otherwise divide it according to the speed
2034                 *of the channel we are going to transmit on
2035                 */
2036                 flen = len;
2037                 if (nfree > 0) {
2038                         if (pch->speed == 0) {
2039                                 flen = len/nfree;
2040                                 if (nbigger > 0) {
2041                                         flen++;
2042                                         nbigger--;
2043                                 }
2044                         } else {
2045                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2046                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
2047                                 if (nbigger > 0) {
2048                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
2049                                         nbigger -= ((totfree - nzero)*pch->speed)/
2050                                                         totspeed;
2051                                 }
2052                         }
2053                         nfree--;
2054                 }
2055
2056                 /*
2057                  *check if we are on the last channel or
2058                  *we exceded the length of the data to
2059                  *fragment
2060                  */
2061                 if ((nfree <= 0) || (flen > len))
2062                         flen = len;
2063                 /*
2064                  *it is not worth to tx on slow channels:
2065                  *in that case from the resulting flen according to the
2066                  *above formula will be equal or less than zero.
2067                  *Skip the channel in this case
2068                  */
2069                 if (flen <= 0) {
2070                         pch->avail = 2;
2071                         spin_unlock(&pch->downl);
2072                         continue;
2073                 }
2074
2075                 /*
2076                  * hdrlen includes the 2-byte PPP protocol field, but the
2077                  * MTU counts only the payload excluding the protocol field.
2078                  * (RFC1661 Section 2)
2079                  */
2080                 mtu = pch->chan->mtu - (hdrlen - 2);
2081                 if (mtu < 4)
2082                         mtu = 4;
2083                 if (flen > mtu)
2084                         flen = mtu;
2085                 if (flen == len)
2086                         bits |= E;
2087                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2088                 if (!frag)
2089                         goto noskb;
2090                 q = skb_put(frag, flen + hdrlen);
2091
2092                 /* make the MP header */
2093                 put_unaligned_be16(PPP_MP, q);
2094                 if (ppp->flags & SC_MP_XSHORTSEQ) {
2095                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2096                         q[3] = ppp->nxseq;
2097                 } else {
2098                         q[2] = bits;
2099                         q[3] = ppp->nxseq >> 16;
2100                         q[4] = ppp->nxseq >> 8;
2101                         q[5] = ppp->nxseq;
2102                 }
2103
2104                 memcpy(q + hdrlen, p, flen);
2105
2106                 /* try to send it down the channel */
2107                 chan = pch->chan;
2108                 if (!skb_queue_empty(&pch->file.xq) ||
2109                         !chan->ops->start_xmit(chan, frag))
2110                         skb_queue_tail(&pch->file.xq, frag);
2111                 pch->had_frag = 1;
2112                 p += flen;
2113                 len -= flen;
2114                 ++ppp->nxseq;
2115                 bits = 0;
2116                 spin_unlock(&pch->downl);
2117         }
2118         ppp->nxchan = i;
2119
2120         return 1;
2121
2122  noskb:
2123         spin_unlock(&pch->downl);
2124         if (ppp->debug & 1)
2125                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2126         ++ppp->dev->stats.tx_errors;
2127         ++ppp->nxseq;
2128         return 1;       /* abandon the frame */
2129 }
2130 #endif /* CONFIG_PPP_MULTILINK */
2131
2132 /* Try to send data out on a channel */
2133 static void __ppp_channel_push(struct channel *pch)
2134 {
2135         struct sk_buff *skb;
2136         struct ppp *ppp;
2137
2138         spin_lock(&pch->downl);
2139         if (pch->chan) {
2140                 while (!skb_queue_empty(&pch->file.xq)) {
2141                         skb = skb_dequeue(&pch->file.xq);
2142                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2143                                 /* put the packet back and try again later */
2144                                 skb_queue_head(&pch->file.xq, skb);
2145                                 break;
2146                         }
2147                 }
2148         } else {
2149                 /* channel got deregistered */
2150                 skb_queue_purge(&pch->file.xq);
2151         }
2152         spin_unlock(&pch->downl);
2153         /* see if there is anything from the attached unit to be sent */
2154         if (skb_queue_empty(&pch->file.xq)) {
2155                 ppp = pch->ppp;
2156                 if (ppp)
2157                         __ppp_xmit_process(ppp, NULL);
2158         }
2159 }
2160
2161 static void ppp_channel_push(struct channel *pch)
2162 {
2163         read_lock_bh(&pch->upl);
2164         if (pch->ppp) {
2165                 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2166                 __ppp_channel_push(pch);
2167                 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2168         } else {
2169                 __ppp_channel_push(pch);
2170         }
2171         read_unlock_bh(&pch->upl);
2172 }
2173
2174 /*
2175  * Receive-side routines.
2176  */
2177
2178 struct ppp_mp_skb_parm {
2179         u32             sequence;
2180         u8              BEbits;
2181 };
2182 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
2183
2184 static inline void
2185 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2186 {
2187         ppp_recv_lock(ppp);
2188         if (!ppp->closing)
2189                 ppp_receive_frame(ppp, skb, pch);
2190         else
2191                 kfree_skb(skb);
2192         ppp_recv_unlock(ppp);
2193 }
2194
2195 /**
2196  * __ppp_decompress_proto - Decompress protocol field, slim version.
2197  * @skb: Socket buffer where protocol field should be decompressed. It must have
2198  *       at least 1 byte of head room and 1 byte of linear data. First byte of
2199  *       data must be a protocol field byte.
2200  *
2201  * Decompress protocol field in PPP header if it's compressed, e.g. when
2202  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2203  * length are done in this function.
2204  */
2205 static void __ppp_decompress_proto(struct sk_buff *skb)
2206 {
2207         if (skb->data[0] & 0x01)
2208                 *(u8 *)skb_push(skb, 1) = 0x00;
2209 }
2210
2211 /**
2212  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2213  * @skb: Socket buffer where protocol field should be decompressed. First byte
2214  *       of data must be a protocol field byte.
2215  *
2216  * Decompress protocol field in PPP header if it's compressed, e.g. when
2217  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2218  * sure that skb data room is sufficient for Protocol field, before and after
2219  * decompression.
2220  *
2221  * Return: true - decompressed successfully, false - not enough room in skb.
2222  */
2223 static bool ppp_decompress_proto(struct sk_buff *skb)
2224 {
2225         /* At least one byte should be present (if protocol is compressed) */
2226         if (!pskb_may_pull(skb, 1))
2227                 return false;
2228
2229         __ppp_decompress_proto(skb);
2230
2231         /* Protocol field should occupy 2 bytes when not compressed */
2232         return pskb_may_pull(skb, 2);
2233 }
2234
2235 /* Attempt to handle a frame via. a bridged channel, if one exists.
2236  * If the channel is bridged, the frame is consumed by the bridge.
2237  * If not, the caller must handle the frame by normal recv mechanisms.
2238  * Returns true if the frame is consumed, false otherwise.
2239  */
2240 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2241 {
2242         struct channel *pchb;
2243
2244         rcu_read_lock();
2245         pchb = rcu_dereference(pch->bridge);
2246         if (!pchb)
2247                 goto out_rcu;
2248
2249         spin_lock(&pchb->downl);
2250         if (!pchb->chan) {
2251                 /* channel got unregistered */
2252                 kfree_skb(skb);
2253                 goto outl;
2254         }
2255
2256         skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2257         if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2258                 kfree_skb(skb);
2259
2260 outl:
2261         spin_unlock(&pchb->downl);
2262 out_rcu:
2263         rcu_read_unlock();
2264
2265         /* If pchb is set then we've consumed the packet */
2266         return !!pchb;
2267 }
2268
2269 void
2270 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2271 {
2272         struct channel *pch = chan->ppp;
2273         int proto;
2274
2275         if (!pch) {
2276                 kfree_skb(skb);
2277                 return;
2278         }
2279
2280         /* If the channel is bridged, transmit via. bridge */
2281         if (ppp_channel_bridge_input(pch, skb))
2282                 return;
2283
2284         read_lock_bh(&pch->upl);
2285         if (!ppp_decompress_proto(skb)) {
2286                 kfree_skb(skb);
2287                 if (pch->ppp) {
2288                         ++pch->ppp->dev->stats.rx_length_errors;
2289                         ppp_receive_error(pch->ppp);
2290                 }
2291                 goto done;
2292         }
2293
2294         proto = PPP_PROTO(skb);
2295         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2296                 /* put it on the channel queue */
2297                 skb_queue_tail(&pch->file.rq, skb);
2298                 /* drop old frames if queue too long */
2299                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2300                        (skb = skb_dequeue(&pch->file.rq)))
2301                         kfree_skb(skb);
2302                 wake_up_interruptible(&pch->file.rwait);
2303         } else {
2304                 ppp_do_recv(pch->ppp, skb, pch);
2305         }
2306
2307 done:
2308         read_unlock_bh(&pch->upl);
2309 }
2310
2311 /* Put a 0-length skb in the receive queue as an error indication */
2312 void
2313 ppp_input_error(struct ppp_channel *chan, int code)
2314 {
2315         struct channel *pch = chan->ppp;
2316         struct sk_buff *skb;
2317
2318         if (!pch)
2319                 return;
2320
2321         read_lock_bh(&pch->upl);
2322         if (pch->ppp) {
2323                 skb = alloc_skb(0, GFP_ATOMIC);
2324                 if (skb) {
2325                         skb->len = 0;           /* probably unnecessary */
2326                         skb->cb[0] = code;
2327                         ppp_do_recv(pch->ppp, skb, pch);
2328                 }
2329         }
2330         read_unlock_bh(&pch->upl);
2331 }
2332
2333 /*
2334  * We come in here to process a received frame.
2335  * The receive side of the ppp unit is locked.
2336  */
2337 static void
2338 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2339 {
2340         /* note: a 0-length skb is used as an error indication */
2341         if (skb->len > 0) {
2342                 skb_checksum_complete_unset(skb);
2343 #ifdef CONFIG_PPP_MULTILINK
2344                 /* XXX do channel-level decompression here */
2345                 if (PPP_PROTO(skb) == PPP_MP)
2346                         ppp_receive_mp_frame(ppp, skb, pch);
2347                 else
2348 #endif /* CONFIG_PPP_MULTILINK */
2349                         ppp_receive_nonmp_frame(ppp, skb);
2350         } else {
2351                 kfree_skb(skb);
2352                 ppp_receive_error(ppp);
2353         }
2354 }
2355
2356 static void
2357 ppp_receive_error(struct ppp *ppp)
2358 {
2359         ++ppp->dev->stats.rx_errors;
2360         if (ppp->vj)
2361                 slhc_toss(ppp->vj);
2362 }
2363
2364 static void
2365 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2366 {
2367         struct sk_buff *ns;
2368         int proto, len, npi;
2369
2370         /*
2371          * Decompress the frame, if compressed.
2372          * Note that some decompressors need to see uncompressed frames
2373          * that come in as well as compressed frames.
2374          */
2375         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2376             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2377                 skb = ppp_decompress_frame(ppp, skb);
2378
2379         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2380                 goto err;
2381
2382         /* At this point the "Protocol" field MUST be decompressed, either in
2383          * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2384          */
2385         proto = PPP_PROTO(skb);
2386         switch (proto) {
2387         case PPP_VJC_COMP:
2388                 /* decompress VJ compressed packets */
2389                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2390                         goto err;
2391
2392                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2393                         /* copy to a new sk_buff with more tailroom */
2394                         ns = dev_alloc_skb(skb->len + 128);
2395                         if (!ns) {
2396                                 netdev_err(ppp->dev, "PPP: no memory "
2397                                            "(VJ decomp)\n");
2398                                 goto err;
2399                         }
2400                         skb_reserve(ns, 2);
2401                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2402                         consume_skb(skb);
2403                         skb = ns;
2404                 }
2405                 else
2406                         skb->ip_summed = CHECKSUM_NONE;
2407
2408                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2409                 if (len <= 0) {
2410                         netdev_printk(KERN_DEBUG, ppp->dev,
2411                                       "PPP: VJ decompression error\n");
2412                         goto err;
2413                 }
2414                 len += 2;
2415                 if (len > skb->len)
2416                         skb_put(skb, len - skb->len);
2417                 else if (len < skb->len)
2418                         skb_trim(skb, len);
2419                 proto = PPP_IP;
2420                 break;
2421
2422         case PPP_VJC_UNCOMP:
2423                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2424                         goto err;
2425
2426                 /* Until we fix the decompressor need to make sure
2427                  * data portion is linear.
2428                  */
2429                 if (!pskb_may_pull(skb, skb->len))
2430                         goto err;
2431
2432                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2433                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2434                         goto err;
2435                 }
2436                 proto = PPP_IP;
2437                 break;
2438
2439         case PPP_CCP:
2440                 ppp_ccp_peek(ppp, skb, 1);
2441                 break;
2442         }
2443
2444         ++ppp->stats64.rx_packets;
2445         ppp->stats64.rx_bytes += skb->len - 2;
2446
2447         npi = proto_to_npindex(proto);
2448         if (npi < 0) {
2449                 /* control or unknown frame - pass it to pppd */
2450                 skb_queue_tail(&ppp->file.rq, skb);
2451                 /* limit queue length by dropping old frames */
2452                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2453                        (skb = skb_dequeue(&ppp->file.rq)))
2454                         kfree_skb(skb);
2455                 /* wake up any process polling or blocking on read */
2456                 wake_up_interruptible(&ppp->file.rwait);
2457
2458         } else {
2459                 /* network protocol frame - give it to the kernel */
2460
2461 #ifdef CONFIG_PPP_FILTER
2462                 /* check if the packet passes the pass and active filters */
2463                 /* the filter instructions are constructed assuming
2464                    a four-byte PPP header on each packet */
2465                 if (ppp->pass_filter || ppp->active_filter) {
2466                         if (skb_unclone(skb, GFP_ATOMIC))
2467                                 goto err;
2468
2469                         *(u8 *)skb_push(skb, 2) = 0;
2470                         if (ppp->pass_filter &&
2471                             bpf_prog_run(ppp->pass_filter, skb) == 0) {
2472                                 if (ppp->debug & 1)
2473                                         netdev_printk(KERN_DEBUG, ppp->dev,
2474                                                       "PPP: inbound frame "
2475                                                       "not passed\n");
2476                                 kfree_skb(skb);
2477                                 return;
2478                         }
2479                         if (!(ppp->active_filter &&
2480                               bpf_prog_run(ppp->active_filter, skb) == 0))
2481                                 ppp->last_recv = jiffies;
2482                         __skb_pull(skb, 2);
2483                 } else
2484 #endif /* CONFIG_PPP_FILTER */
2485                         ppp->last_recv = jiffies;
2486
2487                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2488                     ppp->npmode[npi] != NPMODE_PASS) {
2489                         kfree_skb(skb);
2490                 } else {
2491                         /* chop off protocol */
2492                         skb_pull_rcsum(skb, 2);
2493                         skb->dev = ppp->dev;
2494                         skb->protocol = htons(npindex_to_ethertype[npi]);
2495                         skb_reset_mac_header(skb);
2496                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2497                                                       dev_net(ppp->dev)));
2498                         netif_rx(skb);
2499                 }
2500         }
2501         return;
2502
2503  err:
2504         kfree_skb(skb);
2505         ppp_receive_error(ppp);
2506 }
2507
2508 static struct sk_buff *
2509 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2510 {
2511         int proto = PPP_PROTO(skb);
2512         struct sk_buff *ns;
2513         int len;
2514
2515         /* Until we fix all the decompressor's need to make sure
2516          * data portion is linear.
2517          */
2518         if (!pskb_may_pull(skb, skb->len))
2519                 goto err;
2520
2521         if (proto == PPP_COMP) {
2522                 int obuff_size;
2523
2524                 switch(ppp->rcomp->compress_proto) {
2525                 case CI_MPPE:
2526                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2527                         break;
2528                 default:
2529                         obuff_size = ppp->mru + PPP_HDRLEN;
2530                         break;
2531                 }
2532
2533                 ns = dev_alloc_skb(obuff_size);
2534                 if (!ns) {
2535                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2536                                    "no memory\n");
2537                         goto err;
2538                 }
2539                 /* the decompressor still expects the A/C bytes in the hdr */
2540                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2541                                 skb->len + 2, ns->data, obuff_size);
2542                 if (len < 0) {
2543                         /* Pass the compressed frame to pppd as an
2544                            error indication. */
2545                         if (len == DECOMP_FATALERROR)
2546                                 ppp->rstate |= SC_DC_FERROR;
2547                         kfree_skb(ns);
2548                         goto err;
2549                 }
2550
2551                 consume_skb(skb);
2552                 skb = ns;
2553                 skb_put(skb, len);
2554                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2555
2556                 /* Don't call __ppp_decompress_proto() here, but instead rely on
2557                  * corresponding algo (mppe/bsd/deflate) to decompress it.
2558                  */
2559         } else {
2560                 /* Uncompressed frame - pass to decompressor so it
2561                    can update its dictionary if necessary. */
2562                 if (ppp->rcomp->incomp)
2563                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2564                                            skb->len + 2);
2565         }
2566
2567         return skb;
2568
2569  err:
2570         ppp->rstate |= SC_DC_ERROR;
2571         ppp_receive_error(ppp);
2572         return skb;
2573 }
2574
2575 #ifdef CONFIG_PPP_MULTILINK
2576 /*
2577  * Receive a multilink frame.
2578  * We put it on the reconstruction queue and then pull off
2579  * as many completed frames as we can.
2580  */
2581 static void
2582 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2583 {
2584         u32 mask, seq;
2585         struct channel *ch;
2586         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2587
2588         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2589                 goto err;               /* no good, throw it away */
2590
2591         /* Decode sequence number and begin/end bits */
2592         if (ppp->flags & SC_MP_SHORTSEQ) {
2593                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2594                 mask = 0xfff;
2595         } else {
2596                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2597                 mask = 0xffffff;
2598         }
2599         PPP_MP_CB(skb)->BEbits = skb->data[2];
2600         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2601
2602         /*
2603          * Do protocol ID decompression on the first fragment of each packet.
2604          * We have to do that here, because ppp_receive_nonmp_frame() expects
2605          * decompressed protocol field.
2606          */
2607         if (PPP_MP_CB(skb)->BEbits & B)
2608                 __ppp_decompress_proto(skb);
2609
2610         /*
2611          * Expand sequence number to 32 bits, making it as close
2612          * as possible to ppp->minseq.
2613          */
2614         seq |= ppp->minseq & ~mask;
2615         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2616                 seq += mask + 1;
2617         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2618                 seq -= mask + 1;        /* should never happen */
2619         PPP_MP_CB(skb)->sequence = seq;
2620         pch->lastseq = seq;
2621
2622         /*
2623          * If this packet comes before the next one we were expecting,
2624          * drop it.
2625          */
2626         if (seq_before(seq, ppp->nextseq)) {
2627                 kfree_skb(skb);
2628                 ++ppp->dev->stats.rx_dropped;
2629                 ppp_receive_error(ppp);
2630                 return;
2631         }
2632
2633         /*
2634          * Reevaluate minseq, the minimum over all channels of the
2635          * last sequence number received on each channel.  Because of
2636          * the increasing sequence number rule, we know that any fragment
2637          * before `minseq' which hasn't arrived is never going to arrive.
2638          * The list of channels can't change because we have the receive
2639          * side of the ppp unit locked.
2640          */
2641         list_for_each_entry(ch, &ppp->channels, clist) {
2642                 if (seq_before(ch->lastseq, seq))
2643                         seq = ch->lastseq;
2644         }
2645         if (seq_before(ppp->minseq, seq))
2646                 ppp->minseq = seq;
2647
2648         /* Put the fragment on the reconstruction queue */
2649         ppp_mp_insert(ppp, skb);
2650
2651         /* If the queue is getting long, don't wait any longer for packets
2652            before the start of the queue. */
2653         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2654                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2655                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2656                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2657         }
2658
2659         /* Pull completed packets off the queue and receive them. */
2660         while ((skb = ppp_mp_reconstruct(ppp))) {
2661                 if (pskb_may_pull(skb, 2))
2662                         ppp_receive_nonmp_frame(ppp, skb);
2663                 else {
2664                         ++ppp->dev->stats.rx_length_errors;
2665                         kfree_skb(skb);
2666                         ppp_receive_error(ppp);
2667                 }
2668         }
2669
2670         return;
2671
2672  err:
2673         kfree_skb(skb);
2674         ppp_receive_error(ppp);
2675 }
2676
2677 /*
2678  * Insert a fragment on the MP reconstruction queue.
2679  * The queue is ordered by increasing sequence number.
2680  */
2681 static void
2682 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2683 {
2684         struct sk_buff *p;
2685         struct sk_buff_head *list = &ppp->mrq;
2686         u32 seq = PPP_MP_CB(skb)->sequence;
2687
2688         /* N.B. we don't need to lock the list lock because we have the
2689            ppp unit receive-side lock. */
2690         skb_queue_walk(list, p) {
2691                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2692                         break;
2693         }
2694         __skb_queue_before(list, p, skb);
2695 }
2696
2697 /*
2698  * Reconstruct a packet from the MP fragment queue.
2699  * We go through increasing sequence numbers until we find a
2700  * complete packet, or we get to the sequence number for a fragment
2701  * which hasn't arrived but might still do so.
2702  */
2703 static struct sk_buff *
2704 ppp_mp_reconstruct(struct ppp *ppp)
2705 {
2706         u32 seq = ppp->nextseq;
2707         u32 minseq = ppp->minseq;
2708         struct sk_buff_head *list = &ppp->mrq;
2709         struct sk_buff *p, *tmp;
2710         struct sk_buff *head, *tail;
2711         struct sk_buff *skb = NULL;
2712         int lost = 0, len = 0;
2713
2714         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2715                 return NULL;
2716         head = __skb_peek(list);
2717         tail = NULL;
2718         skb_queue_walk_safe(list, p, tmp) {
2719         again:
2720                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2721                         /* this can't happen, anyway ignore the skb */
2722                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2723                                    "seq %u < %u\n",
2724                                    PPP_MP_CB(p)->sequence, seq);
2725                         __skb_unlink(p, list);
2726                         kfree_skb(p);
2727                         continue;
2728                 }
2729                 if (PPP_MP_CB(p)->sequence != seq) {
2730                         u32 oldseq;
2731                         /* Fragment `seq' is missing.  If it is after
2732                            minseq, it might arrive later, so stop here. */
2733                         if (seq_after(seq, minseq))
2734                                 break;
2735                         /* Fragment `seq' is lost, keep going. */
2736                         lost = 1;
2737                         oldseq = seq;
2738                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2739                                 minseq + 1: PPP_MP_CB(p)->sequence;
2740
2741                         if (ppp->debug & 1)
2742                                 netdev_printk(KERN_DEBUG, ppp->dev,
2743                                               "lost frag %u..%u\n",
2744                                               oldseq, seq-1);
2745
2746                         goto again;
2747                 }
2748
2749                 /*
2750                  * At this point we know that all the fragments from
2751                  * ppp->nextseq to seq are either present or lost.
2752                  * Also, there are no complete packets in the queue
2753                  * that have no missing fragments and end before this
2754                  * fragment.
2755                  */
2756
2757                 /* B bit set indicates this fragment starts a packet */
2758                 if (PPP_MP_CB(p)->BEbits & B) {
2759                         head = p;
2760                         lost = 0;
2761                         len = 0;
2762                 }
2763
2764                 len += p->len;
2765
2766                 /* Got a complete packet yet? */
2767                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2768                     (PPP_MP_CB(head)->BEbits & B)) {
2769                         if (len > ppp->mrru + 2) {
2770                                 ++ppp->dev->stats.rx_length_errors;
2771                                 netdev_printk(KERN_DEBUG, ppp->dev,
2772                                               "PPP: reconstructed packet"
2773                                               " is too long (%d)\n", len);
2774                         } else {
2775                                 tail = p;
2776                                 break;
2777                         }
2778                         ppp->nextseq = seq + 1;
2779                 }
2780
2781                 /*
2782                  * If this is the ending fragment of a packet,
2783                  * and we haven't found a complete valid packet yet,
2784                  * we can discard up to and including this fragment.
2785                  */
2786                 if (PPP_MP_CB(p)->BEbits & E) {
2787                         struct sk_buff *tmp2;
2788
2789                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2790                                 if (ppp->debug & 1)
2791                                         netdev_printk(KERN_DEBUG, ppp->dev,
2792                                                       "discarding frag %u\n",
2793                                                       PPP_MP_CB(p)->sequence);
2794                                 __skb_unlink(p, list);
2795                                 kfree_skb(p);
2796                         }
2797                         head = skb_peek(list);
2798                         if (!head)
2799                                 break;
2800                 }
2801                 ++seq;
2802         }
2803
2804         /* If we have a complete packet, copy it all into one skb. */
2805         if (tail != NULL) {
2806                 /* If we have discarded any fragments,
2807                    signal a receive error. */
2808                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2809                         skb_queue_walk_safe(list, p, tmp) {
2810                                 if (p == head)
2811                                         break;
2812                                 if (ppp->debug & 1)
2813                                         netdev_printk(KERN_DEBUG, ppp->dev,
2814                                                       "discarding frag %u\n",
2815                                                       PPP_MP_CB(p)->sequence);
2816                                 __skb_unlink(p, list);
2817                                 kfree_skb(p);
2818                         }
2819
2820                         if (ppp->debug & 1)
2821                                 netdev_printk(KERN_DEBUG, ppp->dev,
2822                                               "  missed pkts %u..%u\n",
2823                                               ppp->nextseq,
2824                                               PPP_MP_CB(head)->sequence-1);
2825                         ++ppp->dev->stats.rx_dropped;
2826                         ppp_receive_error(ppp);
2827                 }
2828
2829                 skb = head;
2830                 if (head != tail) {
2831                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2832                         p = skb_queue_next(list, head);
2833                         __skb_unlink(skb, list);
2834                         skb_queue_walk_from_safe(list, p, tmp) {
2835                                 __skb_unlink(p, list);
2836                                 *fragpp = p;
2837                                 p->next = NULL;
2838                                 fragpp = &p->next;
2839
2840                                 skb->len += p->len;
2841                                 skb->data_len += p->len;
2842                                 skb->truesize += p->truesize;
2843
2844                                 if (p == tail)
2845                                         break;
2846                         }
2847                 } else {
2848                         __skb_unlink(skb, list);
2849                 }
2850
2851                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2852         }
2853
2854         return skb;
2855 }
2856 #endif /* CONFIG_PPP_MULTILINK */
2857
2858 /*
2859  * Channel interface.
2860  */
2861
2862 /* Create a new, unattached ppp channel. */
2863 int ppp_register_channel(struct ppp_channel *chan)
2864 {
2865         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2866 }
2867
2868 /* Create a new, unattached ppp channel for specified net. */
2869 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2870 {
2871         struct channel *pch;
2872         struct ppp_net *pn;
2873
2874         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2875         if (!pch)
2876                 return -ENOMEM;
2877
2878         pn = ppp_pernet(net);
2879
2880         pch->ppp = NULL;
2881         pch->chan = chan;
2882         pch->chan_net = get_net(net);
2883         chan->ppp = pch;
2884         init_ppp_file(&pch->file, CHANNEL);
2885         pch->file.hdrlen = chan->hdrlen;
2886 #ifdef CONFIG_PPP_MULTILINK
2887         pch->lastseq = -1;
2888 #endif /* CONFIG_PPP_MULTILINK */
2889         init_rwsem(&pch->chan_sem);
2890         spin_lock_init(&pch->downl);
2891         rwlock_init(&pch->upl);
2892
2893         spin_lock_bh(&pn->all_channels_lock);
2894         pch->file.index = ++pn->last_channel_index;
2895         list_add(&pch->list, &pn->new_channels);
2896         atomic_inc(&channel_count);
2897         spin_unlock_bh(&pn->all_channels_lock);
2898
2899         return 0;
2900 }
2901
2902 /*
2903  * Return the index of a channel.
2904  */
2905 int ppp_channel_index(struct ppp_channel *chan)
2906 {
2907         struct channel *pch = chan->ppp;
2908
2909         if (pch)
2910                 return pch->file.index;
2911         return -1;
2912 }
2913
2914 /*
2915  * Return the PPP unit number to which a channel is connected.
2916  */
2917 int ppp_unit_number(struct ppp_channel *chan)
2918 {
2919         struct channel *pch = chan->ppp;
2920         int unit = -1;
2921
2922         if (pch) {
2923                 read_lock_bh(&pch->upl);
2924                 if (pch->ppp)
2925                         unit = pch->ppp->file.index;
2926                 read_unlock_bh(&pch->upl);
2927         }
2928         return unit;
2929 }
2930
2931 /*
2932  * Return the PPP device interface name of a channel.
2933  */
2934 char *ppp_dev_name(struct ppp_channel *chan)
2935 {
2936         struct channel *pch = chan->ppp;
2937         char *name = NULL;
2938
2939         if (pch) {
2940                 read_lock_bh(&pch->upl);
2941                 if (pch->ppp && pch->ppp->dev)
2942                         name = pch->ppp->dev->name;
2943                 read_unlock_bh(&pch->upl);
2944         }
2945         return name;
2946 }
2947
2948
2949 /*
2950  * Disconnect a channel from the generic layer.
2951  * This must be called in process context.
2952  */
2953 void
2954 ppp_unregister_channel(struct ppp_channel *chan)
2955 {
2956         struct channel *pch = chan->ppp;
2957         struct ppp_net *pn;
2958
2959         if (!pch)
2960                 return;         /* should never happen */
2961
2962         chan->ppp = NULL;
2963
2964         /*
2965          * This ensures that we have returned from any calls into the
2966          * the channel's start_xmit or ioctl routine before we proceed.
2967          */
2968         down_write(&pch->chan_sem);
2969         spin_lock_bh(&pch->downl);
2970         pch->chan = NULL;
2971         spin_unlock_bh(&pch->downl);
2972         up_write(&pch->chan_sem);
2973         ppp_disconnect_channel(pch);
2974
2975         pn = ppp_pernet(pch->chan_net);
2976         spin_lock_bh(&pn->all_channels_lock);
2977         list_del(&pch->list);
2978         spin_unlock_bh(&pn->all_channels_lock);
2979
2980         ppp_unbridge_channels(pch);
2981
2982         pch->file.dead = 1;
2983         wake_up_interruptible(&pch->file.rwait);
2984
2985         if (refcount_dec_and_test(&pch->file.refcnt))
2986                 ppp_destroy_channel(pch);
2987 }
2988
2989 /*
2990  * Callback from a channel when it can accept more to transmit.
2991  * This should be called at BH/softirq level, not interrupt level.
2992  */
2993 void
2994 ppp_output_wakeup(struct ppp_channel *chan)
2995 {
2996         struct channel *pch = chan->ppp;
2997
2998         if (!pch)
2999                 return;
3000         ppp_channel_push(pch);
3001 }
3002
3003 /*
3004  * Compression control.
3005  */
3006
3007 /* Process the PPPIOCSCOMPRESS ioctl. */
3008 static int
3009 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3010 {
3011         int err = -EFAULT;
3012         struct compressor *cp, *ocomp;
3013         void *state, *ostate;
3014         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3015
3016         if (data->length > CCP_MAX_OPTION_LENGTH)
3017                 goto out;
3018         if (copy_from_user(ccp_option, data->ptr, data->length))
3019                 goto out;
3020
3021         err = -EINVAL;
3022         if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3023                 goto out;
3024
3025         cp = try_then_request_module(
3026                 find_compressor(ccp_option[0]),
3027                 "ppp-compress-%d", ccp_option[0]);
3028         if (!cp)
3029                 goto out;
3030
3031         err = -ENOBUFS;
3032         if (data->transmit) {
3033                 state = cp->comp_alloc(ccp_option, data->length);
3034                 if (state) {
3035                         ppp_xmit_lock(ppp);
3036                         ppp->xstate &= ~SC_COMP_RUN;
3037                         ocomp = ppp->xcomp;
3038                         ostate = ppp->xc_state;
3039                         ppp->xcomp = cp;
3040                         ppp->xc_state = state;
3041                         ppp_xmit_unlock(ppp);
3042                         if (ostate) {
3043                                 ocomp->comp_free(ostate);
3044                                 module_put(ocomp->owner);
3045                         }
3046                         err = 0;
3047                 } else
3048                         module_put(cp->owner);
3049
3050         } else {
3051                 state = cp->decomp_alloc(ccp_option, data->length);
3052                 if (state) {
3053                         ppp_recv_lock(ppp);
3054                         ppp->rstate &= ~SC_DECOMP_RUN;
3055                         ocomp = ppp->rcomp;
3056                         ostate = ppp->rc_state;
3057                         ppp->rcomp = cp;
3058                         ppp->rc_state = state;
3059                         ppp_recv_unlock(ppp);
3060                         if (ostate) {
3061                                 ocomp->decomp_free(ostate);
3062                                 module_put(ocomp->owner);
3063                         }
3064                         err = 0;
3065                 } else
3066                         module_put(cp->owner);
3067         }
3068
3069  out:
3070         return err;
3071 }
3072
3073 /*
3074  * Look at a CCP packet and update our state accordingly.
3075  * We assume the caller has the xmit or recv path locked.
3076  */
3077 static void
3078 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3079 {
3080         unsigned char *dp;
3081         int len;
3082
3083         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3084                 return; /* no header */
3085         dp = skb->data + 2;
3086
3087         switch (CCP_CODE(dp)) {
3088         case CCP_CONFREQ:
3089
3090                 /* A ConfReq starts negotiation of compression
3091                  * in one direction of transmission,
3092                  * and hence brings it down...but which way?
3093                  *
3094                  * Remember:
3095                  * A ConfReq indicates what the sender would like to receive
3096                  */
3097                 if(inbound)
3098                         /* He is proposing what I should send */
3099                         ppp->xstate &= ~SC_COMP_RUN;
3100                 else
3101                         /* I am proposing to what he should send */
3102                         ppp->rstate &= ~SC_DECOMP_RUN;
3103
3104                 break;
3105
3106         case CCP_TERMREQ:
3107         case CCP_TERMACK:
3108                 /*
3109                  * CCP is going down, both directions of transmission
3110                  */
3111                 ppp->rstate &= ~SC_DECOMP_RUN;
3112                 ppp->xstate &= ~SC_COMP_RUN;
3113                 break;
3114
3115         case CCP_CONFACK:
3116                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3117                         break;
3118                 len = CCP_LENGTH(dp);
3119                 if (!pskb_may_pull(skb, len + 2))
3120                         return;         /* too short */
3121                 dp += CCP_HDRLEN;
3122                 len -= CCP_HDRLEN;
3123                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3124                         break;
3125                 if (inbound) {
3126                         /* we will start receiving compressed packets */
3127                         if (!ppp->rc_state)
3128                                 break;
3129                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3130                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
3131                                 ppp->rstate |= SC_DECOMP_RUN;
3132                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3133                         }
3134                 } else {
3135                         /* we will soon start sending compressed packets */
3136                         if (!ppp->xc_state)
3137                                 break;
3138                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3139                                         ppp->file.index, 0, ppp->debug))
3140                                 ppp->xstate |= SC_COMP_RUN;
3141                 }
3142                 break;
3143
3144         case CCP_RESETACK:
3145                 /* reset the [de]compressor */
3146                 if ((ppp->flags & SC_CCP_UP) == 0)
3147                         break;
3148                 if (inbound) {
3149                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3150                                 ppp->rcomp->decomp_reset(ppp->rc_state);
3151                                 ppp->rstate &= ~SC_DC_ERROR;
3152                         }
3153                 } else {
3154                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3155                                 ppp->xcomp->comp_reset(ppp->xc_state);
3156                 }
3157                 break;
3158         }
3159 }
3160
3161 /* Free up compression resources. */
3162 static void
3163 ppp_ccp_closed(struct ppp *ppp)
3164 {
3165         void *xstate, *rstate;
3166         struct compressor *xcomp, *rcomp;
3167
3168         ppp_lock(ppp);
3169         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3170         ppp->xstate = 0;
3171         xcomp = ppp->xcomp;
3172         xstate = ppp->xc_state;
3173         ppp->xc_state = NULL;
3174         ppp->rstate = 0;
3175         rcomp = ppp->rcomp;
3176         rstate = ppp->rc_state;
3177         ppp->rc_state = NULL;
3178         ppp_unlock(ppp);
3179
3180         if (xstate) {
3181                 xcomp->comp_free(xstate);
3182                 module_put(xcomp->owner);
3183         }
3184         if (rstate) {
3185                 rcomp->decomp_free(rstate);
3186                 module_put(rcomp->owner);
3187         }
3188 }
3189
3190 /* List of compressors. */
3191 static LIST_HEAD(compressor_list);
3192 static DEFINE_SPINLOCK(compressor_list_lock);
3193
3194 struct compressor_entry {
3195         struct list_head list;
3196         struct compressor *comp;
3197 };
3198
3199 static struct compressor_entry *
3200 find_comp_entry(int proto)
3201 {
3202         struct compressor_entry *ce;
3203
3204         list_for_each_entry(ce, &compressor_list, list) {
3205                 if (ce->comp->compress_proto == proto)
3206                         return ce;
3207         }
3208         return NULL;
3209 }
3210
3211 /* Register a compressor */
3212 int
3213 ppp_register_compressor(struct compressor *cp)
3214 {
3215         struct compressor_entry *ce;
3216         int ret;
3217         spin_lock(&compressor_list_lock);
3218         ret = -EEXIST;
3219         if (find_comp_entry(cp->compress_proto))
3220                 goto out;
3221         ret = -ENOMEM;
3222         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3223         if (!ce)
3224                 goto out;
3225         ret = 0;
3226         ce->comp = cp;
3227         list_add(&ce->list, &compressor_list);
3228  out:
3229         spin_unlock(&compressor_list_lock);
3230         return ret;
3231 }
3232
3233 /* Unregister a compressor */
3234 void
3235 ppp_unregister_compressor(struct compressor *cp)
3236 {
3237         struct compressor_entry *ce;
3238
3239         spin_lock(&compressor_list_lock);
3240         ce = find_comp_entry(cp->compress_proto);
3241         if (ce && ce->comp == cp) {
3242                 list_del(&ce->list);
3243                 kfree(ce);
3244         }
3245         spin_unlock(&compressor_list_lock);
3246 }
3247
3248 /* Find a compressor. */
3249 static struct compressor *
3250 find_compressor(int type)
3251 {
3252         struct compressor_entry *ce;
3253         struct compressor *cp = NULL;
3254
3255         spin_lock(&compressor_list_lock);
3256         ce = find_comp_entry(type);
3257         if (ce) {
3258                 cp = ce->comp;
3259                 if (!try_module_get(cp->owner))
3260                         cp = NULL;
3261         }
3262         spin_unlock(&compressor_list_lock);
3263         return cp;
3264 }
3265
3266 /*
3267  * Miscelleneous stuff.
3268  */
3269
3270 static void
3271 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3272 {
3273         struct slcompress *vj = ppp->vj;
3274
3275         memset(st, 0, sizeof(*st));
3276         st->p.ppp_ipackets = ppp->stats64.rx_packets;
3277         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3278         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3279         st->p.ppp_opackets = ppp->stats64.tx_packets;
3280         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3281         st->p.ppp_obytes = ppp->stats64.tx_bytes;
3282         if (!vj)
3283                 return;
3284         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3285         st->vj.vjs_compressed = vj->sls_o_compressed;
3286         st->vj.vjs_searches = vj->sls_o_searches;
3287         st->vj.vjs_misses = vj->sls_o_misses;
3288         st->vj.vjs_errorin = vj->sls_i_error;
3289         st->vj.vjs_tossed = vj->sls_i_tossed;
3290         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3291         st->vj.vjs_compressedin = vj->sls_i_compressed;
3292 }
3293
3294 /*
3295  * Stuff for handling the lists of ppp units and channels
3296  * and for initialization.
3297  */
3298
3299 /*
3300  * Create a new ppp interface unit.  Fails if it can't allocate memory
3301  * or if there is already a unit with the requested number.
3302  * unit == -1 means allocate a new number.
3303  */
3304 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3305 {
3306         struct ppp_config conf = {
3307                 .file = file,
3308                 .unit = *unit,
3309                 .ifname_is_set = false,
3310         };
3311         struct net_device *dev;
3312         struct ppp *ppp;
3313         int err;
3314
3315         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3316         if (!dev) {
3317                 err = -ENOMEM;
3318                 goto err;
3319         }
3320         dev_net_set(dev, net);
3321         dev->rtnl_link_ops = &ppp_link_ops;
3322
3323         rtnl_lock();
3324
3325         err = ppp_dev_configure(net, dev, &conf);
3326         if (err < 0)
3327                 goto err_dev;
3328         ppp = netdev_priv(dev);
3329         *unit = ppp->file.index;
3330
3331         rtnl_unlock();
3332
3333         return 0;
3334
3335 err_dev:
3336         rtnl_unlock();
3337         free_netdev(dev);
3338 err:
3339         return err;
3340 }
3341
3342 /*
3343  * Initialize a ppp_file structure.
3344  */
3345 static void
3346 init_ppp_file(struct ppp_file *pf, int kind)
3347 {
3348         pf->kind = kind;
3349         skb_queue_head_init(&pf->xq);
3350         skb_queue_head_init(&pf->rq);
3351         refcount_set(&pf->refcnt, 1);
3352         init_waitqueue_head(&pf->rwait);
3353 }
3354
3355 /*
3356  * Free the memory used by a ppp unit.  This is only called once
3357  * there are no channels connected to the unit and no file structs
3358  * that reference the unit.
3359  */
3360 static void ppp_destroy_interface(struct ppp *ppp)
3361 {
3362         atomic_dec(&ppp_unit_count);
3363
3364         if (!ppp->file.dead || ppp->n_channels) {
3365                 /* "can't happen" */
3366                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3367                            "but dead=%d n_channels=%d !\n",
3368                            ppp, ppp->file.dead, ppp->n_channels);
3369                 return;
3370         }
3371
3372         ppp_ccp_closed(ppp);
3373         if (ppp->vj) {
3374                 slhc_free(ppp->vj);
3375                 ppp->vj = NULL;
3376         }
3377         skb_queue_purge(&ppp->file.xq);
3378         skb_queue_purge(&ppp->file.rq);
3379 #ifdef CONFIG_PPP_MULTILINK
3380         skb_queue_purge(&ppp->mrq);
3381 #endif /* CONFIG_PPP_MULTILINK */
3382 #ifdef CONFIG_PPP_FILTER
3383         if (ppp->pass_filter) {
3384                 bpf_prog_destroy(ppp->pass_filter);
3385                 ppp->pass_filter = NULL;
3386         }
3387
3388         if (ppp->active_filter) {
3389                 bpf_prog_destroy(ppp->active_filter);
3390                 ppp->active_filter = NULL;
3391         }
3392 #endif /* CONFIG_PPP_FILTER */
3393
3394         kfree_skb(ppp->xmit_pending);
3395         free_percpu(ppp->xmit_recursion);
3396
3397         free_netdev(ppp->dev);
3398 }
3399
3400 /*
3401  * Locate an existing ppp unit.
3402  * The caller should have locked the all_ppp_mutex.
3403  */
3404 static struct ppp *
3405 ppp_find_unit(struct ppp_net *pn, int unit)
3406 {
3407         return unit_find(&pn->units_idr, unit);
3408 }
3409
3410 /*
3411  * Locate an existing ppp channel.
3412  * The caller should have locked the all_channels_lock.
3413  * First we look in the new_channels list, then in the
3414  * all_channels list.  If found in the new_channels list,
3415  * we move it to the all_channels list.  This is for speed
3416  * when we have a lot of channels in use.
3417  */
3418 static struct channel *
3419 ppp_find_channel(struct ppp_net *pn, int unit)
3420 {
3421         struct channel *pch;
3422
3423         list_for_each_entry(pch, &pn->new_channels, list) {
3424                 if (pch->file.index == unit) {
3425                         list_move(&pch->list, &pn->all_channels);
3426                         return pch;
3427                 }
3428         }
3429
3430         list_for_each_entry(pch, &pn->all_channels, list) {
3431                 if (pch->file.index == unit)
3432                         return pch;
3433         }
3434
3435         return NULL;
3436 }
3437
3438 /*
3439  * Connect a PPP channel to a PPP interface unit.
3440  */
3441 static int
3442 ppp_connect_channel(struct channel *pch, int unit)
3443 {
3444         struct ppp *ppp;
3445         struct ppp_net *pn;
3446         int ret = -ENXIO;
3447         int hdrlen;
3448
3449         pn = ppp_pernet(pch->chan_net);
3450
3451         mutex_lock(&pn->all_ppp_mutex);
3452         ppp = ppp_find_unit(pn, unit);
3453         if (!ppp)
3454                 goto out;
3455         write_lock_bh(&pch->upl);
3456         ret = -EINVAL;
3457         if (pch->ppp ||
3458             rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3459                 goto outl;
3460
3461         ppp_lock(ppp);
3462         spin_lock_bh(&pch->downl);
3463         if (!pch->chan) {
3464                 /* Don't connect unregistered channels */
3465                 spin_unlock_bh(&pch->downl);
3466                 ppp_unlock(ppp);
3467                 ret = -ENOTCONN;
3468                 goto outl;
3469         }
3470         spin_unlock_bh(&pch->downl);
3471         if (pch->file.hdrlen > ppp->file.hdrlen)
3472                 ppp->file.hdrlen = pch->file.hdrlen;
3473         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3474         if (hdrlen > ppp->dev->hard_header_len)
3475                 ppp->dev->hard_header_len = hdrlen;
3476         list_add_tail(&pch->clist, &ppp->channels);
3477         ++ppp->n_channels;
3478         pch->ppp = ppp;
3479         refcount_inc(&ppp->file.refcnt);
3480         ppp_unlock(ppp);
3481         ret = 0;
3482
3483  outl:
3484         write_unlock_bh(&pch->upl);
3485  out:
3486         mutex_unlock(&pn->all_ppp_mutex);
3487         return ret;
3488 }
3489
3490 /*
3491  * Disconnect a channel from its ppp unit.
3492  */
3493 static int
3494 ppp_disconnect_channel(struct channel *pch)
3495 {
3496         struct ppp *ppp;
3497         int err = -EINVAL;
3498
3499         write_lock_bh(&pch->upl);
3500         ppp = pch->ppp;
3501         pch->ppp = NULL;
3502         write_unlock_bh(&pch->upl);
3503         if (ppp) {
3504                 /* remove it from the ppp unit's list */
3505                 ppp_lock(ppp);
3506                 list_del(&pch->clist);
3507                 if (--ppp->n_channels == 0)
3508                         wake_up_interruptible(&ppp->file.rwait);
3509                 ppp_unlock(ppp);
3510                 if (refcount_dec_and_test(&ppp->file.refcnt))
3511                         ppp_destroy_interface(ppp);
3512                 err = 0;
3513         }
3514         return err;
3515 }
3516
3517 /*
3518  * Free up the resources used by a ppp channel.
3519  */
3520 static void ppp_destroy_channel(struct channel *pch)
3521 {
3522         put_net(pch->chan_net);
3523         pch->chan_net = NULL;
3524
3525         atomic_dec(&channel_count);
3526
3527         if (!pch->file.dead) {
3528                 /* "can't happen" */
3529                 pr_err("ppp: destroying undead channel %p !\n", pch);
3530                 return;
3531         }
3532         skb_queue_purge(&pch->file.xq);
3533         skb_queue_purge(&pch->file.rq);
3534         kfree(pch);
3535 }
3536
3537 static void __exit ppp_cleanup(void)
3538 {
3539         /* should never happen */
3540         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3541                 pr_err("PPP: removing module but units remain!\n");
3542         rtnl_link_unregister(&ppp_link_ops);
3543         unregister_chrdev(PPP_MAJOR, "ppp");
3544         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3545         class_destroy(ppp_class);
3546         unregister_pernet_device(&ppp_net_ops);
3547 }
3548
3549 /*
3550  * Units handling. Caller must protect concurrent access
3551  * by holding all_ppp_mutex
3552  */
3553
3554 /* associate pointer with specified number */
3555 static int unit_set(struct idr *p, void *ptr, int n)
3556 {
3557         int unit;
3558
3559         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3560         if (unit == -ENOSPC)
3561                 unit = -EINVAL;
3562         return unit;
3563 }
3564
3565 /* get new free unit number and associate pointer with it */
3566 static int unit_get(struct idr *p, void *ptr, int min)
3567 {
3568         return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3569 }
3570
3571 /* put unit number back to a pool */
3572 static void unit_put(struct idr *p, int n)
3573 {
3574         idr_remove(p, n);
3575 }
3576
3577 /* get pointer associated with the number */
3578 static void *unit_find(struct idr *p, int n)
3579 {
3580         return idr_find(p, n);
3581 }
3582
3583 /* Module/initialization stuff */
3584
3585 module_init(ppp_init);
3586 module_exit(ppp_cleanup);
3587
3588 EXPORT_SYMBOL(ppp_register_net_channel);
3589 EXPORT_SYMBOL(ppp_register_channel);
3590 EXPORT_SYMBOL(ppp_unregister_channel);
3591 EXPORT_SYMBOL(ppp_channel_index);
3592 EXPORT_SYMBOL(ppp_unit_number);
3593 EXPORT_SYMBOL(ppp_dev_name);
3594 EXPORT_SYMBOL(ppp_input);
3595 EXPORT_SYMBOL(ppp_input_error);
3596 EXPORT_SYMBOL(ppp_output_wakeup);
3597 EXPORT_SYMBOL(ppp_register_compressor);
3598 EXPORT_SYMBOL(ppp_unregister_compressor);
3599 MODULE_LICENSE("GPL");
3600 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3601 MODULE_ALIAS_RTNL_LINK("ppp");
3602 MODULE_ALIAS("devname:ppp");