drivers/net/ppp/ppp_generic.c

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