drivers/net/ppp/ppp_generic.c

   1 /*
   2  * Generic PPP layer for Linux.
   3  *
   4  * Copyright 1999-2002 Paul Mackerras.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  *
  11  * The generic PPP layer handles the PPP network interfaces, the
  12  * /dev/ppp device, packet and VJ compression, and multilink.
  13  * It talks to PPP `channels' via the interface defined in
  14  * include/linux/ppp_channel.h.  Channels provide the basic means for
  15  * sending and receiving PPP frames on some kind of communications
  16  * channel.
  17  *
  18  * Part of the code in this driver was inspired by the old async-only
  19  * PPP driver, written by Michael Callahan and Al Longyear, and
  20  * subsequently hacked by Paul Mackerras.
  21  *
  22  * ==FILEVERSION 20041108==
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/kmod.h>
  28 #include <linux/init.h>
  29 #include <linux/list.h>
  30 #include <linux/idr.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/poll.h>
  33 #include <linux/ppp_defs.h>
  34 #include <linux/filter.h>
  35 #include <linux/if_ppp.h>
  36 #include <linux/ppp_channel.h>
  37 #include <linux/ppp-comp.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/rtnetlink.h>
  40 #include <linux/if_arp.h>
  41 #include <linux/ip.h>
  42 #include <linux/tcp.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/rwsem.h>
  45 #include <linux/stddef.h>
  46 #include <linux/device.h>
  47 #include <linux/mutex.h>
  48 #include <linux/slab.h>
  49 #include <asm/unaligned.h>
  50 #include <net/slhc_vj.h>
  51 #include <linux/atomic.h>
  52
  53 #include <linux/nsproxy.h>
  54 #include <net/net_namespace.h>
  55 #include <net/netns/generic.h>
  56
  57 #define PPP_VERSION     "2.4.2"
  58
  59 /*
  60  * Network protocols we support.
  61  */
  62 #define NP_IP   0               /* Internet Protocol V4 */
  63 #define NP_IPV6 1               /* Internet Protocol V6 */
  64 #define NP_IPX  2               /* IPX protocol */
  65 #define NP_AT   3               /* Appletalk protocol */
  66 #define NP_MPLS_UC 4            /* MPLS unicast */
  67 #define NP_MPLS_MC 5            /* MPLS multicast */
  68 #define NUM_NP  6               /* Number of NPs. */
  69
  70 #define MPHDRLEN        6       /* multilink protocol header length */
  71 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  72
  73 /*
  74  * An instance of /dev/ppp can be associated with either a ppp
  75  * interface unit or a ppp channel.  In both cases, file->private_data
  76  * points to one of these.
  77  */
  78 struct ppp_file {
  79         enum {
  80                 INTERFACE=1, CHANNEL
  81         }               kind;
  82         struct sk_buff_head xq;         /* pppd transmit queue */
  83         struct sk_buff_head rq;         /* receive queue for pppd */
  84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  86         int             hdrlen;         /* space to leave for headers */
  87         int             index;          /* interface unit / channel number */
  88         int             dead;           /* unit/channel has been shut down */
  89 };
  90
  91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  92
  93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  95
  96 /*
  97  * Data structure describing one ppp unit.
  98  * A ppp unit corresponds to a ppp network interface device
  99  * and represents a multilink bundle.
 100  * It can have 0 or more ppp channels connected to it.
 101  */
 102 struct ppp {
 103         struct ppp_file file;           /* stuff for read/write/poll 0 */
 104         struct file     *owner;         /* file that owns this unit 48 */
 105         struct list_head channels;      /* list of attached channels 4c */
 106         int             n_channels;     /* how many channels are attached 54 */
 107         spinlock_t      rlock;          /* lock for receive side 58 */
 108         spinlock_t      wlock;          /* lock for transmit side 5c */
 109         int             mru;            /* max receive unit 60 */
 110         unsigned int    flags;          /* control bits 64 */
 111         unsigned int    xstate;         /* transmit state bits 68 */
 112         unsigned int    rstate;         /* receive state bits 6c */
 113         int             debug;          /* debug flags 70 */
 114         struct slcompress *vj;          /* state for VJ header compression */
 115         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 116         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 117         struct compressor *xcomp;       /* transmit packet compressor 8c */
 118         void            *xc_state;      /* its internal state 90 */
 119         struct compressor *rcomp;       /* receive decompressor 94 */
 120         void            *rc_state;      /* its internal state 98 */
 121         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 122         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 123         struct net_device *dev;         /* network interface device a4 */
 124         int             closing;        /* is device closing down? a8 */
 125 #ifdef CONFIG_PPP_MULTILINK
 126         int             nxchan;         /* next channel to send something on */
 127         u32             nxseq;          /* next sequence number to send */
 128         int             mrru;           /* MP: max reconst. receive unit */
 129         u32             nextseq;        /* MP: seq no of next packet */
 130         u32             minseq;         /* MP: min of most recent seqnos */
 131         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 132 #endif /* CONFIG_PPP_MULTILINK */
 133 #ifdef CONFIG_PPP_FILTER
 134         struct sock_filter *pass_filter;        /* filter for packets to pass */
 135         struct sock_filter *active_filter;/* filter for pkts to reset idle */
 136         unsigned pass_len, active_len;
 137 #endif /* CONFIG_PPP_FILTER */
 138         struct net      *ppp_net;       /* the net we belong to */
 139 };
 140
 141 /*
 142  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 143  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 144  * SC_MUST_COMP
 145  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 146  * Bits in xstate: SC_COMP_RUN
 147  */
 148 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 149                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 150                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 151
 152 /*
 153  * Private data structure for each channel.
 154  * This includes the data structure used for multilink.
 155  */
 156 struct channel {
 157         struct ppp_file file;           /* stuff for read/write/poll */
 158         struct list_head list;          /* link in all/new_channels list */
 159         struct ppp_channel *chan;       /* public channel data structure */
 160         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 161         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 162         struct ppp      *ppp;           /* ppp unit we're connected to */
 163         struct net      *chan_net;      /* the net channel belongs to */
 164         struct list_head clist;         /* link in list of channels per unit */
 165         rwlock_t        upl;            /* protects `ppp' */
 166 #ifdef CONFIG_PPP_MULTILINK
 167         u8              avail;          /* flag used in multilink stuff */
 168         u8              had_frag;       /* >= 1 fragments have been sent */
 169         u32             lastseq;        /* MP: last sequence # received */
 170         int             speed;          /* speed of the corresponding ppp channel*/
 171 #endif /* CONFIG_PPP_MULTILINK */
 172 };
 173
 174 /*
 175  * SMP locking issues:
 176  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 177  * list and the ppp.n_channels field, you need to take both locks
 178  * before you modify them.
 179  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 180  * channel.downl.
 181  */
 182
 183 static DEFINE_MUTEX(ppp_mutex);
 184 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 185 static atomic_t channel_count = ATOMIC_INIT(0);
 186
 187 /* per-net private data for this module */
 188 static int ppp_net_id __read_mostly;
 189 struct ppp_net {
 190         /* units to ppp mapping */
 191         struct idr units_idr;
 192
 193         /*
 194          * all_ppp_mutex protects the units_idr mapping.
 195          * It also ensures that finding a ppp unit in the units_idr
 196          * map and updating its file.refcnt field is atomic.
 197          */
 198         struct mutex all_ppp_mutex;
 199
 200         /* channels */
 201         struct list_head all_channels;
 202         struct list_head new_channels;
 203         int last_channel_index;
 204
 205         /*
 206          * all_channels_lock protects all_channels and
 207          * last_channel_index, and the atomicity of find
 208          * a channel and updating its file.refcnt field.
 209          */
 210         spinlock_t all_channels_lock;
 211 };
 212
 213 /* Get the PPP protocol number from a skb */
 214 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 215
 216 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 217 #define PPP_MAX_RQLEN   32
 218
 219 /*
 220  * Maximum number of multilink fragments queued up.
 221  * This has to be large enough to cope with the maximum latency of
 222  * the slowest channel relative to the others.  Strictly it should
 223  * depend on the number of channels and their characteristics.
 224  */
 225 #define PPP_MP_MAX_QLEN 128
 226
 227 /* Multilink header bits. */
 228 #define B       0x80            /* this fragment begins a packet */
 229 #define E       0x40            /* this fragment ends a packet */
 230
 231 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 232 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 233 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 234
 235 /* Prototypes. */
 236 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 237                         struct file *file, unsigned int cmd, unsigned long arg);
 238 static void ppp_xmit_process(struct ppp *ppp);
 239 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 240 static void ppp_push(struct ppp *ppp);
 241 static void ppp_channel_push(struct channel *pch);
 242 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 243                               struct channel *pch);
 244 static void ppp_receive_error(struct ppp *ppp);
 245 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 246 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 247                                             struct sk_buff *skb);
 248 #ifdef CONFIG_PPP_MULTILINK
 249 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 250                                 struct channel *pch);
 251 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 252 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 253 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 254 #endif /* CONFIG_PPP_MULTILINK */
 255 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 256 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 257 static void ppp_ccp_closed(struct ppp *ppp);
 258 static struct compressor *find_compressor(int type);
 259 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 260 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 261 static void init_ppp_file(struct ppp_file *pf, int kind);
 262 static void ppp_shutdown_interface(struct ppp *ppp);
 263 static void ppp_destroy_interface(struct ppp *ppp);
 264 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 265 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 266 static int ppp_connect_channel(struct channel *pch, int unit);
 267 static int ppp_disconnect_channel(struct channel *pch);
 268 static void ppp_destroy_channel(struct channel *pch);
 269 static int unit_get(struct idr *p, void *ptr);
 270 static int unit_set(struct idr *p, void *ptr, int n);
 271 static void unit_put(struct idr *p, int n);
 272 static void *unit_find(struct idr *p, int n);
 273
 274 static struct class *ppp_class;
 275
 276 /* per net-namespace data */
 277 static inline struct ppp_net *ppp_pernet(struct net *net)
 278 {
 279         BUG_ON(!net);
 280
 281         return net_generic(net, ppp_net_id);
 282 }
 283
 284 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 285 static inline int proto_to_npindex(int proto)
 286 {
 287         switch (proto) {
 288         case PPP_IP:
 289                 return NP_IP;
 290         case PPP_IPV6:
 291                 return NP_IPV6;
 292         case PPP_IPX:
 293                 return NP_IPX;
 294         case PPP_AT:
 295                 return NP_AT;
 296         case PPP_MPLS_UC:
 297                 return NP_MPLS_UC;
 298         case PPP_MPLS_MC:
 299                 return NP_MPLS_MC;
 300         }
 301         return -EINVAL;
 302 }
 303
 304 /* Translates an NP index into a PPP protocol number */
 305 static const int npindex_to_proto[NUM_NP] = {
 306         PPP_IP,
 307         PPP_IPV6,
 308         PPP_IPX,
 309         PPP_AT,
 310         PPP_MPLS_UC,
 311         PPP_MPLS_MC,
 312 };
 313
 314 /* Translates an ethertype into an NP index */
 315 static inline int ethertype_to_npindex(int ethertype)
 316 {
 317         switch (ethertype) {
 318         case ETH_P_IP:
 319                 return NP_IP;
 320         case ETH_P_IPV6:
 321                 return NP_IPV6;
 322         case ETH_P_IPX:
 323                 return NP_IPX;
 324         case ETH_P_PPPTALK:
 325         case ETH_P_ATALK:
 326                 return NP_AT;
 327         case ETH_P_MPLS_UC:
 328                 return NP_MPLS_UC;
 329         case ETH_P_MPLS_MC:
 330                 return NP_MPLS_MC;
 331         }
 332         return -1;
 333 }
 334
 335 /* Translates an NP index into an ethertype */
 336 static const int npindex_to_ethertype[NUM_NP] = {
 337         ETH_P_IP,
 338         ETH_P_IPV6,
 339         ETH_P_IPX,
 340         ETH_P_PPPTALK,
 341         ETH_P_MPLS_UC,
 342         ETH_P_MPLS_MC,
 343 };
 344
 345 /*
 346  * Locking shorthand.
 347  */
 348 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 349 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 350 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 351 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 352 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 353                                      ppp_recv_lock(ppp); } while (0)
 354 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 355                                      ppp_xmit_unlock(ppp); } while (0)
 356
 357 /*
 358  * /dev/ppp device routines.
 359  * The /dev/ppp device is used by pppd to control the ppp unit.
 360  * It supports the read, write, ioctl and poll functions.
 361  * Open instances of /dev/ppp can be in one of three states:
 362  * unattached, attached to a ppp unit, or attached to a ppp channel.
 363  */
 364 static int ppp_open(struct inode *inode, struct file *file)
 365 {
 366         /*
 367          * This could (should?) be enforced by the permissions on /dev/ppp.
 368          */
 369         if (!capable(CAP_NET_ADMIN))
 370                 return -EPERM;
 371         return 0;
 372 }
 373
 374 static int ppp_release(struct inode *unused, struct file *file)
 375 {
 376         struct ppp_file *pf = file->private_data;
 377         struct ppp *ppp;
 378
 379         if (pf) {
 380                 file->private_data = NULL;
 381                 if (pf->kind == INTERFACE) {
 382                         ppp = PF_TO_PPP(pf);
 383                         if (file == ppp->owner)
 384                                 ppp_shutdown_interface(ppp);
 385                 }
 386                 if (atomic_dec_and_test(&pf->refcnt)) {
 387                         switch (pf->kind) {
 388                         case INTERFACE:
 389                                 ppp_destroy_interface(PF_TO_PPP(pf));
 390                                 break;
 391                         case CHANNEL:
 392                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 393                                 break;
 394                         }
 395                 }
 396         }
 397         return 0;
 398 }
 399
 400 static ssize_t ppp_read(struct file *file, char __user *buf,
 401                         size_t count, loff_t *ppos)
 402 {
 403         struct ppp_file *pf = file->private_data;
 404         DECLARE_WAITQUEUE(wait, current);
 405         ssize_t ret;
 406         struct sk_buff *skb = NULL;
 407         struct iovec iov;
 408
 409         ret = count;
 410
 411         if (!pf)
 412                 return -ENXIO;
 413         add_wait_queue(&pf->rwait, &wait);
 414         for (;;) {
 415                 set_current_state(TASK_INTERRUPTIBLE);
 416                 skb = skb_dequeue(&pf->rq);
 417                 if (skb)
 418                         break;
 419                 ret = 0;
 420                 if (pf->dead)
 421                         break;
 422                 if (pf->kind == INTERFACE) {
 423                         /*
 424                          * Return 0 (EOF) on an interface that has no
 425                          * channels connected, unless it is looping
 426                          * network traffic (demand mode).
 427                          */
 428                         struct ppp *ppp = PF_TO_PPP(pf);
 429                         if (ppp->n_channels == 0 &&
 430                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 431                                 break;
 432                 }
 433                 ret = -EAGAIN;
 434                 if (file->f_flags & O_NONBLOCK)
 435                         break;
 436                 ret = -ERESTARTSYS;
 437                 if (signal_pending(current))
 438                         break;
 439                 schedule();
 440         }
 441         set_current_state(TASK_RUNNING);
 442         remove_wait_queue(&pf->rwait, &wait);
 443
 444         if (!skb)
 445                 goto out;
 446
 447         ret = -EOVERFLOW;
 448         if (skb->len > count)
 449                 goto outf;
 450         ret = -EFAULT;
 451         iov.iov_base = buf;
 452         iov.iov_len = count;
 453         if (skb_copy_datagram_iovec(skb, 0, &iov, skb->len))
 454                 goto outf;
 455         ret = skb->len;
 456
 457  outf:
 458         kfree_skb(skb);
 459  out:
 460         return ret;
 461 }
 462
 463 static ssize_t ppp_write(struct file *file, const char __user *buf,
 464                          size_t count, loff_t *ppos)
 465 {
 466         struct ppp_file *pf = file->private_data;
 467         struct sk_buff *skb;
 468         ssize_t ret;
 469
 470         if (!pf)
 471                 return -ENXIO;
 472         ret = -ENOMEM;
 473         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 474         if (!skb)
 475                 goto out;
 476         skb_reserve(skb, pf->hdrlen);
 477         ret = -EFAULT;
 478         if (copy_from_user(skb_put(skb, count), buf, count)) {
 479                 kfree_skb(skb);
 480                 goto out;
 481         }
 482
 483         skb_queue_tail(&pf->xq, skb);
 484
 485         switch (pf->kind) {
 486         case INTERFACE:
 487                 ppp_xmit_process(PF_TO_PPP(pf));
 488                 break;
 489         case CHANNEL:
 490                 ppp_channel_push(PF_TO_CHANNEL(pf));
 491                 break;
 492         }
 493
 494         ret = count;
 495
 496  out:
 497         return ret;
 498 }
 499
 500 /* No kernel lock - fine */
 501 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 502 {
 503         struct ppp_file *pf = file->private_data;
 504         unsigned int mask;
 505
 506         if (!pf)
 507                 return 0;
 508         poll_wait(file, &pf->rwait, wait);
 509         mask = POLLOUT | POLLWRNORM;
 510         if (skb_peek(&pf->rq))
 511                 mask |= POLLIN | POLLRDNORM;
 512         if (pf->dead)
 513                 mask |= POLLHUP;
 514         else if (pf->kind == INTERFACE) {
 515                 /* see comment in ppp_read */
 516                 struct ppp *ppp = PF_TO_PPP(pf);
 517                 if (ppp->n_channels == 0 &&
 518                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 519                         mask |= POLLIN | POLLRDNORM;
 520         }
 521
 522         return mask;
 523 }
 524
 525 #ifdef CONFIG_PPP_FILTER
 526 static int get_filter(void __user *arg, struct sock_filter **p)
 527 {
 528         struct sock_fprog uprog;
 529         struct sock_filter *code = NULL;
 530         int len, err;
 531
 532         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 533                 return -EFAULT;
 534
 535         if (!uprog.len) {
 536                 *p = NULL;
 537                 return 0;
 538         }
 539
 540         len = uprog.len * sizeof(struct sock_filter);
 541         code = memdup_user(uprog.filter, len);
 542         if (IS_ERR(code))
 543                 return PTR_ERR(code);
 544
 545         err = sk_chk_filter(code, uprog.len);
 546         if (err) {
 547                 kfree(code);
 548                 return err;
 549         }
 550
 551         *p = code;
 552         return uprog.len;
 553 }
 554 #endif /* CONFIG_PPP_FILTER */
 555
 556 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 557 {
 558         struct ppp_file *pf;
 559         struct ppp *ppp;
 560         int err = -EFAULT, val, val2, i;
 561         struct ppp_idle idle;
 562         struct npioctl npi;
 563         int unit, cflags;
 564         struct slcompress *vj;
 565         void __user *argp = (void __user *)arg;
 566         int __user *p = argp;
 567
 568         mutex_lock(&ppp_mutex);
 569
 570         pf = file->private_data;
 571         if (!pf) {
 572                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
 573                                            pf, file, cmd, arg);
 574                 goto out;
 575         }
 576
 577         if (cmd == PPPIOCDETACH) {
 578                 /*
 579                  * We have to be careful here... if the file descriptor
 580                  * has been dup'd, we could have another process in the
 581                  * middle of a poll using the same file *, so we had
 582                  * better not free the interface data structures -
 583                  * instead we fail the ioctl.  Even in this case, we
 584                  * shut down the interface if we are the owner of it.
 585                  * Actually, we should get rid of PPPIOCDETACH, userland
 586                  * (i.e. pppd) could achieve the same effect by closing
 587                  * this fd and reopening /dev/ppp.
 588                  */
 589                 err = -EINVAL;
 590                 if (pf->kind == INTERFACE) {
 591                         ppp = PF_TO_PPP(pf);
 592                         if (file == ppp->owner)
 593                                 ppp_shutdown_interface(ppp);
 594                 }
 595                 if (atomic_long_read(&file->f_count) < 2) {
 596                         ppp_release(NULL, file);
 597                         err = 0;
 598                 } else
 599                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 600                                 atomic_long_read(&file->f_count));
 601                 goto out;
 602         }
 603
 604         if (pf->kind == CHANNEL) {
 605                 struct channel *pch;
 606                 struct ppp_channel *chan;
 607
 608                 pch = PF_TO_CHANNEL(pf);
 609
 610                 switch (cmd) {
 611                 case PPPIOCCONNECT:
 612                         if (get_user(unit, p))
 613                                 break;
 614                         err = ppp_connect_channel(pch, unit);
 615                         break;
 616
 617                 case PPPIOCDISCONN:
 618                         err = ppp_disconnect_channel(pch);
 619                         break;
 620
 621                 default:
 622                         down_read(&pch->chan_sem);
 623                         chan = pch->chan;
 624                         err = -ENOTTY;
 625                         if (chan && chan->ops->ioctl)
 626                                 err = chan->ops->ioctl(chan, cmd, arg);
 627                         up_read(&pch->chan_sem);
 628                 }
 629                 goto out;
 630         }
 631
 632         if (pf->kind != INTERFACE) {
 633                 /* can't happen */
 634                 pr_err("PPP: not interface or channel??\n");
 635                 err = -EINVAL;
 636                 goto out;
 637         }
 638
 639         ppp = PF_TO_PPP(pf);
 640         switch (cmd) {
 641         case PPPIOCSMRU:
 642                 if (get_user(val, p))
 643                         break;
 644                 ppp->mru = val;
 645                 err = 0;
 646                 break;
 647
 648         case PPPIOCSFLAGS:
 649                 if (get_user(val, p))
 650                         break;
 651                 ppp_lock(ppp);
 652                 cflags = ppp->flags & ~val;
 653                 ppp->flags = val & SC_FLAG_BITS;
 654                 ppp_unlock(ppp);
 655                 if (cflags & SC_CCP_OPEN)
 656                         ppp_ccp_closed(ppp);
 657                 err = 0;
 658                 break;
 659
 660         case PPPIOCGFLAGS:
 661                 val = ppp->flags | ppp->xstate | ppp->rstate;
 662                 if (put_user(val, p))
 663                         break;
 664                 err = 0;
 665                 break;
 666
 667         case PPPIOCSCOMPRESS:
 668                 err = ppp_set_compress(ppp, arg);
 669                 break;
 670
 671         case PPPIOCGUNIT:
 672                 if (put_user(ppp->file.index, p))
 673                         break;
 674                 err = 0;
 675                 break;
 676
 677         case PPPIOCSDEBUG:
 678                 if (get_user(val, p))
 679                         break;
 680                 ppp->debug = val;
 681                 err = 0;
 682                 break;
 683
 684         case PPPIOCGDEBUG:
 685                 if (put_user(ppp->debug, p))
 686                         break;
 687                 err = 0;
 688                 break;
 689
 690         case PPPIOCGIDLE:
 691                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 692                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 693                 if (copy_to_user(argp, &idle, sizeof(idle)))
 694                         break;
 695                 err = 0;
 696                 break;
 697
 698         case PPPIOCSMAXCID:
 699                 if (get_user(val, p))
 700                         break;
 701                 val2 = 15;
 702                 if ((val >> 16) != 0) {
 703                         val2 = val >> 16;
 704                         val &= 0xffff;
 705                 }
 706                 vj = slhc_init(val2+1, val+1);
 707                 if (IS_ERR(vj)) {
 708                         err = PTR_ERR(vj);
 709                         break;
 710                 }
 711                 ppp_lock(ppp);
 712                 if (ppp->vj)
 713                         slhc_free(ppp->vj);
 714                 ppp->vj = vj;
 715                 ppp_unlock(ppp);
 716                 err = 0;
 717                 break;
 718
 719         case PPPIOCGNPMODE:
 720         case PPPIOCSNPMODE:
 721                 if (copy_from_user(&npi, argp, sizeof(npi)))
 722                         break;
 723                 err = proto_to_npindex(npi.protocol);
 724                 if (err < 0)
 725                         break;
 726                 i = err;
 727                 if (cmd == PPPIOCGNPMODE) {
 728                         err = -EFAULT;
 729                         npi.mode = ppp->npmode[i];
 730                         if (copy_to_user(argp, &npi, sizeof(npi)))
 731                                 break;
 732                 } else {
 733                         ppp->npmode[i] = npi.mode;
 734                         /* we may be able to transmit more packets now (??) */
 735                         netif_wake_queue(ppp->dev);
 736                 }
 737                 err = 0;
 738                 break;
 739
 740 #ifdef CONFIG_PPP_FILTER
 741         case PPPIOCSPASS:
 742         {
 743                 struct sock_filter *code;
 744                 err = get_filter(argp, &code);
 745                 if (err >= 0) {
 746                         ppp_lock(ppp);
 747                         kfree(ppp->pass_filter);
 748                         ppp->pass_filter = code;
 749                         ppp->pass_len = err;
 750                         ppp_unlock(ppp);
 751                         err = 0;
 752                 }
 753                 break;
 754         }
 755         case PPPIOCSACTIVE:
 756         {
 757                 struct sock_filter *code;
 758                 err = get_filter(argp, &code);
 759                 if (err >= 0) {
 760                         ppp_lock(ppp);
 761                         kfree(ppp->active_filter);
 762                         ppp->active_filter = code;
 763                         ppp->active_len = err;
 764                         ppp_unlock(ppp);
 765                         err = 0;
 766                 }
 767                 break;
 768         }
 769 #endif /* CONFIG_PPP_FILTER */
 770
 771 #ifdef CONFIG_PPP_MULTILINK
 772         case PPPIOCSMRRU:
 773                 if (get_user(val, p))
 774                         break;
 775                 ppp_recv_lock(ppp);
 776                 ppp->mrru = val;
 777                 ppp_recv_unlock(ppp);
 778                 err = 0;
 779                 break;
 780 #endif /* CONFIG_PPP_MULTILINK */
 781
 782         default:
 783                 err = -ENOTTY;
 784         }
 785
 786 out:
 787         mutex_unlock(&ppp_mutex);
 788
 789         return err;
 790 }
 791
 792 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 793                         struct file *file, unsigned int cmd, unsigned long arg)
 794 {
 795         int unit, err = -EFAULT;
 796         struct ppp *ppp;
 797         struct channel *chan;
 798         struct ppp_net *pn;
 799         int __user *p = (int __user *)arg;
 800
 801         switch (cmd) {
 802         case PPPIOCNEWUNIT:
 803                 /* Create a new ppp unit */
 804                 if (get_user(unit, p))
 805                         break;
 806                 ppp = ppp_create_interface(net, unit, &err);
 807                 if (!ppp)
 808                         break;
 809                 file->private_data = &ppp->file;
 810                 ppp->owner = file;
 811                 err = -EFAULT;
 812                 if (put_user(ppp->file.index, p))
 813                         break;
 814                 err = 0;
 815                 break;
 816
 817         case PPPIOCATTACH:
 818                 /* Attach to an existing ppp unit */
 819                 if (get_user(unit, p))
 820                         break;
 821                 err = -ENXIO;
 822                 pn = ppp_pernet(net);
 823                 mutex_lock(&pn->all_ppp_mutex);
 824                 ppp = ppp_find_unit(pn, unit);
 825                 if (ppp) {
 826                         atomic_inc(&ppp->file.refcnt);
 827                         file->private_data = &ppp->file;
 828                         err = 0;
 829                 }
 830                 mutex_unlock(&pn->all_ppp_mutex);
 831                 break;
 832
 833         case PPPIOCATTCHAN:
 834                 if (get_user(unit, p))
 835                         break;
 836                 err = -ENXIO;
 837                 pn = ppp_pernet(net);
 838                 spin_lock_bh(&pn->all_channels_lock);
 839                 chan = ppp_find_channel(pn, unit);
 840                 if (chan) {
 841                         atomic_inc(&chan->file.refcnt);
 842                         file->private_data = &chan->file;
 843                         err = 0;
 844                 }
 845                 spin_unlock_bh(&pn->all_channels_lock);
 846                 break;
 847
 848         default:
 849                 err = -ENOTTY;
 850         }
 851
 852         return err;
 853 }
 854
 855 static const struct file_operations ppp_device_fops = {
 856         .owner          = THIS_MODULE,
 857         .read           = ppp_read,
 858         .write          = ppp_write,
 859         .poll           = ppp_poll,
 860         .unlocked_ioctl = ppp_ioctl,
 861         .open           = ppp_open,
 862         .release        = ppp_release,
 863         .llseek         = noop_llseek,
 864 };
 865
 866 static __net_init int ppp_init_net(struct net *net)
 867 {
 868         struct ppp_net *pn = net_generic(net, ppp_net_id);
 869
 870         idr_init(&pn->units_idr);
 871         mutex_init(&pn->all_ppp_mutex);
 872
 873         INIT_LIST_HEAD(&pn->all_channels);
 874         INIT_LIST_HEAD(&pn->new_channels);
 875
 876         spin_lock_init(&pn->all_channels_lock);
 877
 878         return 0;
 879 }
 880
 881 static __net_exit void ppp_exit_net(struct net *net)
 882 {
 883         struct ppp_net *pn = net_generic(net, ppp_net_id);
 884
 885         idr_destroy(&pn->units_idr);
 886 }
 887
 888 static struct pernet_operations ppp_net_ops = {
 889         .init = ppp_init_net,
 890         .exit = ppp_exit_net,
 891         .id   = &ppp_net_id,
 892         .size = sizeof(struct ppp_net),
 893 };
 894
 895 #define PPP_MAJOR       108
 896
 897 /* Called at boot time if ppp is compiled into the kernel,
 898    or at module load time (from init_module) if compiled as a module. */
 899 static int __init ppp_init(void)
 900 {
 901         int err;
 902
 903         pr_info("PPP generic driver version " PPP_VERSION "\n");
 904
 905         err = register_pernet_device(&ppp_net_ops);
 906         if (err) {
 907                 pr_err("failed to register PPP pernet device (%d)\n", err);
 908                 goto out;
 909         }
 910
 911         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 912         if (err) {
 913                 pr_err("failed to register PPP device (%d)\n", err);
 914                 goto out_net;
 915         }
 916
 917         ppp_class = class_create(THIS_MODULE, "ppp");
 918         if (IS_ERR(ppp_class)) {
 919                 err = PTR_ERR(ppp_class);
 920                 goto out_chrdev;
 921         }
 922
 923         /* not a big deal if we fail here :-) */
 924         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 925
 926         return 0;
 927
 928 out_chrdev:
 929         unregister_chrdev(PPP_MAJOR, "ppp");
 930 out_net:
 931         unregister_pernet_device(&ppp_net_ops);
 932 out:
 933         return err;
 934 }
 935
 936 /*
 937  * Network interface unit routines.
 938  */
 939 static netdev_tx_t
 940 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 941 {
 942         struct ppp *ppp = netdev_priv(dev);
 943         int npi, proto;
 944         unsigned char *pp;
 945
 946         npi = ethertype_to_npindex(ntohs(skb->protocol));
 947         if (npi < 0)
 948                 goto outf;
 949
 950         /* Drop, accept or reject the packet */
 951         switch (ppp->npmode[npi]) {
 952         case NPMODE_PASS:
 953                 break;
 954         case NPMODE_QUEUE:
 955                 /* it would be nice to have a way to tell the network
 956                    system to queue this one up for later. */
 957                 goto outf;
 958         case NPMODE_DROP:
 959         case NPMODE_ERROR:
 960                 goto outf;
 961         }
 962
 963         /* Put the 2-byte PPP protocol number on the front,
 964            making sure there is room for the address and control fields. */
 965         if (skb_cow_head(skb, PPP_HDRLEN))
 966                 goto outf;
 967
 968         pp = skb_push(skb, 2);
 969         proto = npindex_to_proto[npi];
 970         put_unaligned_be16(proto, pp);
 971
 972         skb_queue_tail(&ppp->file.xq, skb);
 973         ppp_xmit_process(ppp);
 974         return NETDEV_TX_OK;
 975
 976  outf:
 977         kfree_skb(skb);
 978         ++dev->stats.tx_dropped;
 979         return NETDEV_TX_OK;
 980 }
 981
 982 static int
 983 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 984 {
 985         struct ppp *ppp = netdev_priv(dev);
 986         int err = -EFAULT;
 987         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
 988         struct ppp_stats stats;
 989         struct ppp_comp_stats cstats;
 990         char *vers;
 991
 992         switch (cmd) {
 993         case SIOCGPPPSTATS:
 994                 ppp_get_stats(ppp, &stats);
 995                 if (copy_to_user(addr, &stats, sizeof(stats)))
 996                         break;
 997                 err = 0;
 998                 break;
 999
1000         case SIOCGPPPCSTATS:
1001                 memset(&cstats, 0, sizeof(cstats));
1002                 if (ppp->xc_state)
1003                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1004                 if (ppp->rc_state)
1005                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1006                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1007                         break;
1008                 err = 0;
1009                 break;
1010
1011         case SIOCGPPPVER:
1012                 vers = PPP_VERSION;
1013                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1014                         break;
1015                 err = 0;
1016                 break;
1017
1018         default:
1019                 err = -EINVAL;
1020         }
1021
1022         return err;
1023 }
1024
1025 static const struct net_device_ops ppp_netdev_ops = {
1026         .ndo_start_xmit = ppp_start_xmit,
1027         .ndo_do_ioctl   = ppp_net_ioctl,
1028 };
1029
1030 static void ppp_setup(struct net_device *dev)
1031 {
1032         dev->netdev_ops = &ppp_netdev_ops;
1033         dev->hard_header_len = PPP_HDRLEN;
1034         dev->mtu = PPP_MTU;
1035         dev->addr_len = 0;
1036         dev->tx_queue_len = 3;
1037         dev->type = ARPHRD_PPP;
1038         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1039         dev->features |= NETIF_F_NETNS_LOCAL;
1040         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1041 }
1042
1043 /*
1044  * Transmit-side routines.
1045  */
1046
1047 /*
1048  * Called to do any work queued up on the transmit side
1049  * that can now be done.
1050  */
1051 static void
1052 ppp_xmit_process(struct ppp *ppp)
1053 {
1054         struct sk_buff *skb;
1055
1056         ppp_xmit_lock(ppp);
1057         if (!ppp->closing) {
1058                 ppp_push(ppp);
1059                 while (!ppp->xmit_pending &&
1060                        (skb = skb_dequeue(&ppp->file.xq)))
1061                         ppp_send_frame(ppp, skb);
1062                 /* If there's no work left to do, tell the core net
1063                    code that we can accept some more. */
1064                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1065                         netif_wake_queue(ppp->dev);
1066                 else
1067                         netif_stop_queue(ppp->dev);
1068         }
1069         ppp_xmit_unlock(ppp);
1070 }
1071
1072 static inline struct sk_buff *
1073 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1074 {
1075         struct sk_buff *new_skb;
1076         int len;
1077         int new_skb_size = ppp->dev->mtu +
1078                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1079         int compressor_skb_size = ppp->dev->mtu +
1080                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1081         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1082         if (!new_skb) {
1083                 if (net_ratelimit())
1084                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1085                 return NULL;
1086         }
1087         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1088                 skb_reserve(new_skb,
1089                             ppp->dev->hard_header_len - PPP_HDRLEN);
1090
1091         /* compressor still expects A/C bytes in hdr */
1092         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1093                                    new_skb->data, skb->len + 2,
1094                                    compressor_skb_size);
1095         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1096                 kfree_skb(skb);
1097                 skb = new_skb;
1098                 skb_put(skb, len);
1099                 skb_pull(skb, 2);       /* pull off A/C bytes */
1100         } else if (len == 0) {
1101                 /* didn't compress, or CCP not up yet */
1102                 kfree_skb(new_skb);
1103                 new_skb = skb;
1104         } else {
1105                 /*
1106                  * (len < 0)
1107                  * MPPE requires that we do not send unencrypted
1108                  * frames.  The compressor will return -1 if we
1109                  * should drop the frame.  We cannot simply test
1110                  * the compress_proto because MPPE and MPPC share
1111                  * the same number.
1112                  */
1113                 if (net_ratelimit())
1114                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1115                 kfree_skb(skb);
1116                 kfree_skb(new_skb);
1117                 new_skb = NULL;
1118         }
1119         return new_skb;
1120 }
1121
1122 /*
1123  * Compress and send a frame.
1124  * The caller should have locked the xmit path,
1125  * and xmit_pending should be 0.
1126  */
1127 static void
1128 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1129 {
1130         int proto = PPP_PROTO(skb);
1131         struct sk_buff *new_skb;
1132         int len;
1133         unsigned char *cp;
1134
1135         if (proto < 0x8000) {
1136 #ifdef CONFIG_PPP_FILTER
1137                 /* check if we should pass this packet */
1138                 /* the filter instructions are constructed assuming
1139                    a four-byte PPP header on each packet */
1140                 *skb_push(skb, 2) = 1;
1141                 if (ppp->pass_filter &&
1142                     sk_run_filter(skb, ppp->pass_filter) == 0) {
1143                         if (ppp->debug & 1)
1144                                 netdev_printk(KERN_DEBUG, ppp->dev,
1145                                               "PPP: outbound frame "
1146                                               "not passed\n");
1147                         kfree_skb(skb);
1148                         return;
1149                 }
1150                 /* if this packet passes the active filter, record the time */
1151                 if (!(ppp->active_filter &&
1152                       sk_run_filter(skb, ppp->active_filter) == 0))
1153                         ppp->last_xmit = jiffies;
1154                 skb_pull(skb, 2);
1155 #else
1156                 /* for data packets, record the time */
1157                 ppp->last_xmit = jiffies;
1158 #endif /* CONFIG_PPP_FILTER */
1159         }
1160
1161         ++ppp->dev->stats.tx_packets;
1162         ppp->dev->stats.tx_bytes += skb->len - 2;
1163
1164         switch (proto) {
1165         case PPP_IP:
1166                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1167                         break;
1168                 /* try to do VJ TCP header compression */
1169                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1170                                     GFP_ATOMIC);
1171                 if (!new_skb) {
1172                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1173                         goto drop;
1174                 }
1175                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1176                 cp = skb->data + 2;
1177                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1178                                     new_skb->data + 2, &cp,
1179                                     !(ppp->flags & SC_NO_TCP_CCID));
1180                 if (cp == skb->data + 2) {
1181                         /* didn't compress */
1182                         kfree_skb(new_skb);
1183                 } else {
1184                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1185                                 proto = PPP_VJC_COMP;
1186                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1187                         } else {
1188                                 proto = PPP_VJC_UNCOMP;
1189                                 cp[0] = skb->data[2];
1190                         }
1191                         kfree_skb(skb);
1192                         skb = new_skb;
1193                         cp = skb_put(skb, len + 2);
1194                         cp[0] = 0;
1195                         cp[1] = proto;
1196                 }
1197                 break;
1198
1199         case PPP_CCP:
1200                 /* peek at outbound CCP frames */
1201                 ppp_ccp_peek(ppp, skb, 0);
1202                 break;
1203         }
1204
1205         /* try to do packet compression */
1206         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1207             proto != PPP_LCP && proto != PPP_CCP) {
1208                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1209                         if (net_ratelimit())
1210                                 netdev_err(ppp->dev,
1211                                            "ppp: compression required but "
1212                                            "down - pkt dropped.\n");
1213                         goto drop;
1214                 }
1215                 skb = pad_compress_skb(ppp, skb);
1216                 if (!skb)
1217                         goto drop;
1218         }
1219
1220         /*
1221          * If we are waiting for traffic (demand dialling),
1222          * queue it up for pppd to receive.
1223          */
1224         if (ppp->flags & SC_LOOP_TRAFFIC) {
1225                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1226                         goto drop;
1227                 skb_queue_tail(&ppp->file.rq, skb);
1228                 wake_up_interruptible(&ppp->file.rwait);
1229                 return;
1230         }
1231
1232         ppp->xmit_pending = skb;
1233         ppp_push(ppp);
1234         return;
1235
1236  drop:
1237         kfree_skb(skb);
1238         ++ppp->dev->stats.tx_errors;
1239 }
1240
1241 /*
1242  * Try to send the frame in xmit_pending.
1243  * The caller should have the xmit path locked.
1244  */
1245 static void
1246 ppp_push(struct ppp *ppp)
1247 {
1248         struct list_head *list;
1249         struct channel *pch;
1250         struct sk_buff *skb = ppp->xmit_pending;
1251
1252         if (!skb)
1253                 return;
1254
1255         list = &ppp->channels;
1256         if (list_empty(list)) {
1257                 /* nowhere to send the packet, just drop it */
1258                 ppp->xmit_pending = NULL;
1259                 kfree_skb(skb);
1260                 return;
1261         }
1262
1263         if ((ppp->flags & SC_MULTILINK) == 0) {
1264                 /* not doing multilink: send it down the first channel */
1265                 list = list->next;
1266                 pch = list_entry(list, struct channel, clist);
1267
1268                 spin_lock_bh(&pch->downl);
1269                 if (pch->chan) {
1270                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1271                                 ppp->xmit_pending = NULL;
1272                 } else {
1273                         /* channel got unregistered */
1274                         kfree_skb(skb);
1275                         ppp->xmit_pending = NULL;
1276                 }
1277                 spin_unlock_bh(&pch->downl);
1278                 return;
1279         }
1280
1281 #ifdef CONFIG_PPP_MULTILINK
1282         /* Multilink: fragment the packet over as many links
1283            as can take the packet at the moment. */
1284         if (!ppp_mp_explode(ppp, skb))
1285                 return;
1286 #endif /* CONFIG_PPP_MULTILINK */
1287
1288         ppp->xmit_pending = NULL;
1289         kfree_skb(skb);
1290 }
1291
1292 #ifdef CONFIG_PPP_MULTILINK
1293 static bool mp_protocol_compress __read_mostly = true;
1294 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1295 MODULE_PARM_DESC(mp_protocol_compress,
1296                  "compress protocol id in multilink fragments");
1297
1298 /*
1299  * Divide a packet to be transmitted into fragments and
1300  * send them out the individual links.
1301  */
1302 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1303 {
1304         int len, totlen;
1305         int i, bits, hdrlen, mtu;
1306         int flen;
1307         int navail, nfree, nzero;
1308         int nbigger;
1309         int totspeed;
1310         int totfree;
1311         unsigned char *p, *q;
1312         struct list_head *list;
1313         struct channel *pch;
1314         struct sk_buff *frag;
1315         struct ppp_channel *chan;
1316
1317         totspeed = 0; /*total bitrate of the bundle*/
1318         nfree = 0; /* # channels which have no packet already queued */
1319         navail = 0; /* total # of usable channels (not deregistered) */
1320         nzero = 0; /* number of channels with zero speed associated*/
1321         totfree = 0; /*total # of channels available and
1322                                   *having no queued packets before
1323                                   *starting the fragmentation*/
1324
1325         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1326         i = 0;
1327         list_for_each_entry(pch, &ppp->channels, clist) {
1328                 if (pch->chan) {
1329                         pch->avail = 1;
1330                         navail++;
1331                         pch->speed = pch->chan->speed;
1332                 } else {
1333                         pch->avail = 0;
1334                 }
1335                 if (pch->avail) {
1336                         if (skb_queue_empty(&pch->file.xq) ||
1337                                 !pch->had_frag) {
1338                                         if (pch->speed == 0)
1339                                                 nzero++;
1340                                         else
1341                                                 totspeed += pch->speed;
1342
1343                                         pch->avail = 2;
1344                                         ++nfree;
1345                                         ++totfree;
1346                                 }
1347                         if (!pch->had_frag && i < ppp->nxchan)
1348                                 ppp->nxchan = i;
1349                 }
1350                 ++i;
1351         }
1352         /*
1353          * Don't start sending this packet unless at least half of
1354          * the channels are free.  This gives much better TCP
1355          * performance if we have a lot of channels.
1356          */
1357         if (nfree == 0 || nfree < navail / 2)
1358                 return 0; /* can't take now, leave it in xmit_pending */
1359
1360         /* Do protocol field compression */
1361         p = skb->data;
1362         len = skb->len;
1363         if (*p == 0 && mp_protocol_compress) {
1364                 ++p;
1365                 --len;
1366         }
1367
1368         totlen = len;
1369         nbigger = len % nfree;
1370
1371         /* skip to the channel after the one we last used
1372            and start at that one */
1373         list = &ppp->channels;
1374         for (i = 0; i < ppp->nxchan; ++i) {
1375                 list = list->next;
1376                 if (list == &ppp->channels) {
1377                         i = 0;
1378                         break;
1379                 }
1380         }
1381
1382         /* create a fragment for each channel */
1383         bits = B;
1384         while (len > 0) {
1385                 list = list->next;
1386                 if (list == &ppp->channels) {
1387                         i = 0;
1388                         continue;
1389                 }
1390                 pch = list_entry(list, struct channel, clist);
1391                 ++i;
1392                 if (!pch->avail)
1393                         continue;
1394
1395                 /*
1396                  * Skip this channel if it has a fragment pending already and
1397                  * we haven't given a fragment to all of the free channels.
1398                  */
1399                 if (pch->avail == 1) {
1400                         if (nfree > 0)
1401                                 continue;
1402                 } else {
1403                         pch->avail = 1;
1404                 }
1405
1406                 /* check the channel's mtu and whether it is still attached. */
1407                 spin_lock_bh(&pch->downl);
1408                 if (pch->chan == NULL) {
1409                         /* can't use this channel, it's being deregistered */
1410                         if (pch->speed == 0)
1411                                 nzero--;
1412                         else
1413                                 totspeed -= pch->speed;
1414
1415                         spin_unlock_bh(&pch->downl);
1416                         pch->avail = 0;
1417                         totlen = len;
1418                         totfree--;
1419                         nfree--;
1420                         if (--navail == 0)
1421                                 break;
1422                         continue;
1423                 }
1424
1425                 /*
1426                 *if the channel speed is not set divide
1427                 *the packet evenly among the free channels;
1428                 *otherwise divide it according to the speed
1429                 *of the channel we are going to transmit on
1430                 */
1431                 flen = len;
1432                 if (nfree > 0) {
1433                         if (pch->speed == 0) {
1434                                 flen = len/nfree;
1435                                 if (nbigger > 0) {
1436                                         flen++;
1437                                         nbigger--;
1438                                 }
1439                         } else {
1440                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1441                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1442                                 if (nbigger > 0) {
1443                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1444                                         nbigger -= ((totfree - nzero)*pch->speed)/
1445                                                         totspeed;
1446                                 }
1447                         }
1448                         nfree--;
1449                 }
1450
1451                 /*
1452                  *check if we are on the last channel or
1453                  *we exceded the length of the data to
1454                  *fragment
1455                  */
1456                 if ((nfree <= 0) || (flen > len))
1457                         flen = len;
1458                 /*
1459                  *it is not worth to tx on slow channels:
1460                  *in that case from the resulting flen according to the
1461                  *above formula will be equal or less than zero.
1462                  *Skip the channel in this case
1463                  */
1464                 if (flen <= 0) {
1465                         pch->avail = 2;
1466                         spin_unlock_bh(&pch->downl);
1467                         continue;
1468                 }
1469
1470                 /*
1471                  * hdrlen includes the 2-byte PPP protocol field, but the
1472                  * MTU counts only the payload excluding the protocol field.
1473                  * (RFC1661 Section 2)
1474                  */
1475                 mtu = pch->chan->mtu - (hdrlen - 2);
1476                 if (mtu < 4)
1477                         mtu = 4;
1478                 if (flen > mtu)
1479                         flen = mtu;
1480                 if (flen == len)
1481                         bits |= E;
1482                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1483                 if (!frag)
1484                         goto noskb;
1485                 q = skb_put(frag, flen + hdrlen);
1486
1487                 /* make the MP header */
1488                 put_unaligned_be16(PPP_MP, q);
1489                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1490                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1491                         q[3] = ppp->nxseq;
1492                 } else {
1493                         q[2] = bits;
1494                         q[3] = ppp->nxseq >> 16;
1495                         q[4] = ppp->nxseq >> 8;
1496                         q[5] = ppp->nxseq;
1497                 }
1498
1499                 memcpy(q + hdrlen, p, flen);
1500
1501                 /* try to send it down the channel */
1502                 chan = pch->chan;
1503                 if (!skb_queue_empty(&pch->file.xq) ||
1504                         !chan->ops->start_xmit(chan, frag))
1505                         skb_queue_tail(&pch->file.xq, frag);
1506                 pch->had_frag = 1;
1507                 p += flen;
1508                 len -= flen;
1509                 ++ppp->nxseq;
1510                 bits = 0;
1511                 spin_unlock_bh(&pch->downl);
1512         }
1513         ppp->nxchan = i;
1514
1515         return 1;
1516
1517  noskb:
1518         spin_unlock_bh(&pch->downl);
1519         if (ppp->debug & 1)
1520                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1521         ++ppp->dev->stats.tx_errors;
1522         ++ppp->nxseq;
1523         return 1;       /* abandon the frame */
1524 }
1525 #endif /* CONFIG_PPP_MULTILINK */
1526
1527 /*
1528  * Try to send data out on a channel.
1529  */
1530 static void
1531 ppp_channel_push(struct channel *pch)
1532 {
1533         struct sk_buff *skb;
1534         struct ppp *ppp;
1535
1536         spin_lock_bh(&pch->downl);
1537         if (pch->chan) {
1538                 while (!skb_queue_empty(&pch->file.xq)) {
1539                         skb = skb_dequeue(&pch->file.xq);
1540                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1541                                 /* put the packet back and try again later */
1542                                 skb_queue_head(&pch->file.xq, skb);
1543                                 break;
1544                         }
1545                 }
1546         } else {
1547                 /* channel got deregistered */
1548                 skb_queue_purge(&pch->file.xq);
1549         }
1550         spin_unlock_bh(&pch->downl);
1551         /* see if there is anything from the attached unit to be sent */
1552         if (skb_queue_empty(&pch->file.xq)) {
1553                 read_lock_bh(&pch->upl);
1554                 ppp = pch->ppp;
1555                 if (ppp)
1556                         ppp_xmit_process(ppp);
1557                 read_unlock_bh(&pch->upl);
1558         }
1559 }
1560
1561 /*
1562  * Receive-side routines.
1563  */
1564
1565 struct ppp_mp_skb_parm {
1566         u32             sequence;
1567         u8              BEbits;
1568 };
1569 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1570
1571 static inline void
1572 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1573 {
1574         ppp_recv_lock(ppp);
1575         if (!ppp->closing)
1576                 ppp_receive_frame(ppp, skb, pch);
1577         else
1578                 kfree_skb(skb);
1579         ppp_recv_unlock(ppp);
1580 }
1581
1582 void
1583 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1584 {
1585         struct channel *pch = chan->ppp;
1586         int proto;
1587
1588         if (!pch) {
1589                 kfree_skb(skb);
1590                 return;
1591         }
1592
1593         read_lock_bh(&pch->upl);
1594         if (!pskb_may_pull(skb, 2)) {
1595                 kfree_skb(skb);
1596                 if (pch->ppp) {
1597                         ++pch->ppp->dev->stats.rx_length_errors;
1598                         ppp_receive_error(pch->ppp);
1599                 }
1600                 goto done;
1601         }
1602
1603         proto = PPP_PROTO(skb);
1604         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1605                 /* put it on the channel queue */
1606                 skb_queue_tail(&pch->file.rq, skb);
1607                 /* drop old frames if queue too long */
1608                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1609                        (skb = skb_dequeue(&pch->file.rq)))
1610                         kfree_skb(skb);
1611                 wake_up_interruptible(&pch->file.rwait);
1612         } else {
1613                 ppp_do_recv(pch->ppp, skb, pch);
1614         }
1615
1616 done:
1617         read_unlock_bh(&pch->upl);
1618 }
1619
1620 /* Put a 0-length skb in the receive queue as an error indication */
1621 void
1622 ppp_input_error(struct ppp_channel *chan, int code)
1623 {
1624         struct channel *pch = chan->ppp;
1625         struct sk_buff *skb;
1626
1627         if (!pch)
1628                 return;
1629
1630         read_lock_bh(&pch->upl);
1631         if (pch->ppp) {
1632                 skb = alloc_skb(0, GFP_ATOMIC);
1633                 if (skb) {
1634                         skb->len = 0;           /* probably unnecessary */
1635                         skb->cb[0] = code;
1636                         ppp_do_recv(pch->ppp, skb, pch);
1637                 }
1638         }
1639         read_unlock_bh(&pch->upl);
1640 }
1641
1642 /*
1643  * We come in here to process a received frame.
1644  * The receive side of the ppp unit is locked.
1645  */
1646 static void
1647 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1648 {
1649         /* note: a 0-length skb is used as an error indication */
1650         if (skb->len > 0) {
1651 #ifdef CONFIG_PPP_MULTILINK
1652                 /* XXX do channel-level decompression here */
1653                 if (PPP_PROTO(skb) == PPP_MP)
1654                         ppp_receive_mp_frame(ppp, skb, pch);
1655                 else
1656 #endif /* CONFIG_PPP_MULTILINK */
1657                         ppp_receive_nonmp_frame(ppp, skb);
1658         } else {
1659                 kfree_skb(skb);
1660                 ppp_receive_error(ppp);
1661         }
1662 }
1663
1664 static void
1665 ppp_receive_error(struct ppp *ppp)
1666 {
1667         ++ppp->dev->stats.rx_errors;
1668         if (ppp->vj)
1669                 slhc_toss(ppp->vj);
1670 }
1671
1672 static void
1673 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1674 {
1675         struct sk_buff *ns;
1676         int proto, len, npi;
1677
1678         /*
1679          * Decompress the frame, if compressed.
1680          * Note that some decompressors need to see uncompressed frames
1681          * that come in as well as compressed frames.
1682          */
1683         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1684             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1685                 skb = ppp_decompress_frame(ppp, skb);
1686
1687         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1688                 goto err;
1689
1690         proto = PPP_PROTO(skb);
1691         switch (proto) {
1692         case PPP_VJC_COMP:
1693                 /* decompress VJ compressed packets */
1694                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1695                         goto err;
1696
1697                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1698                         /* copy to a new sk_buff with more tailroom */
1699                         ns = dev_alloc_skb(skb->len + 128);
1700                         if (!ns) {
1701                                 netdev_err(ppp->dev, "PPP: no memory "
1702                                            "(VJ decomp)\n");
1703                                 goto err;
1704                         }
1705                         skb_reserve(ns, 2);
1706                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1707                         kfree_skb(skb);
1708                         skb = ns;
1709                 }
1710                 else
1711                         skb->ip_summed = CHECKSUM_NONE;
1712
1713                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1714                 if (len <= 0) {
1715                         netdev_printk(KERN_DEBUG, ppp->dev,
1716                                       "PPP: VJ decompression error\n");
1717                         goto err;
1718                 }
1719                 len += 2;
1720                 if (len > skb->len)
1721                         skb_put(skb, len - skb->len);
1722                 else if (len < skb->len)
1723                         skb_trim(skb, len);
1724                 proto = PPP_IP;
1725                 break;
1726
1727         case PPP_VJC_UNCOMP:
1728                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1729                         goto err;
1730
1731                 /* Until we fix the decompressor need to make sure
1732                  * data portion is linear.
1733                  */
1734                 if (!pskb_may_pull(skb, skb->len))
1735                         goto err;
1736
1737                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1738                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1739                         goto err;
1740                 }
1741                 proto = PPP_IP;
1742                 break;
1743
1744         case PPP_CCP:
1745                 ppp_ccp_peek(ppp, skb, 1);
1746                 break;
1747         }
1748
1749         ++ppp->dev->stats.rx_packets;
1750         ppp->dev->stats.rx_bytes += skb->len - 2;
1751
1752         npi = proto_to_npindex(proto);
1753         if (npi < 0) {
1754                 /* control or unknown frame - pass it to pppd */
1755                 skb_queue_tail(&ppp->file.rq, skb);
1756                 /* limit queue length by dropping old frames */
1757                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1758                        (skb = skb_dequeue(&ppp->file.rq)))
1759                         kfree_skb(skb);
1760                 /* wake up any process polling or blocking on read */
1761                 wake_up_interruptible(&ppp->file.rwait);
1762
1763         } else {
1764                 /* network protocol frame - give it to the kernel */
1765
1766 #ifdef CONFIG_PPP_FILTER
1767                 /* check if the packet passes the pass and active filters */
1768                 /* the filter instructions are constructed assuming
1769                    a four-byte PPP header on each packet */
1770                 if (ppp->pass_filter || ppp->active_filter) {
1771                         if (skb_cloned(skb) &&
1772                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1773                                 goto err;
1774
1775                         *skb_push(skb, 2) = 0;
1776                         if (ppp->pass_filter &&
1777                             sk_run_filter(skb, ppp->pass_filter) == 0) {
1778                                 if (ppp->debug & 1)
1779                                         netdev_printk(KERN_DEBUG, ppp->dev,
1780                                                       "PPP: inbound frame "
1781                                                       "not passed\n");
1782                                 kfree_skb(skb);
1783                                 return;
1784                         }
1785                         if (!(ppp->active_filter &&
1786                               sk_run_filter(skb, ppp->active_filter) == 0))
1787                                 ppp->last_recv = jiffies;
1788                         __skb_pull(skb, 2);
1789                 } else
1790 #endif /* CONFIG_PPP_FILTER */
1791                         ppp->last_recv = jiffies;
1792
1793                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1794                     ppp->npmode[npi] != NPMODE_PASS) {
1795                         kfree_skb(skb);
1796                 } else {
1797                         /* chop off protocol */
1798                         skb_pull_rcsum(skb, 2);
1799                         skb->dev = ppp->dev;
1800                         skb->protocol = htons(npindex_to_ethertype[npi]);
1801                         skb_reset_mac_header(skb);
1802                         netif_rx(skb);
1803                 }
1804         }
1805         return;
1806
1807  err:
1808         kfree_skb(skb);
1809         ppp_receive_error(ppp);
1810 }
1811
1812 static struct sk_buff *
1813 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1814 {
1815         int proto = PPP_PROTO(skb);
1816         struct sk_buff *ns;
1817         int len;
1818
1819         /* Until we fix all the decompressor's need to make sure
1820          * data portion is linear.
1821          */
1822         if (!pskb_may_pull(skb, skb->len))
1823                 goto err;
1824
1825         if (proto == PPP_COMP) {
1826                 int obuff_size;
1827
1828                 switch(ppp->rcomp->compress_proto) {
1829                 case CI_MPPE:
1830                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1831                         break;
1832                 default:
1833                         obuff_size = ppp->mru + PPP_HDRLEN;
1834                         break;
1835                 }
1836
1837                 ns = dev_alloc_skb(obuff_size);
1838                 if (!ns) {
1839                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1840                                    "no memory\n");
1841                         goto err;
1842                 }
1843                 /* the decompressor still expects the A/C bytes in the hdr */
1844                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1845                                 skb->len + 2, ns->data, obuff_size);
1846                 if (len < 0) {
1847                         /* Pass the compressed frame to pppd as an
1848                            error indication. */
1849                         if (len == DECOMP_FATALERROR)
1850                                 ppp->rstate |= SC_DC_FERROR;
1851                         kfree_skb(ns);
1852                         goto err;
1853                 }
1854
1855                 kfree_skb(skb);
1856                 skb = ns;
1857                 skb_put(skb, len);
1858                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1859
1860         } else {
1861                 /* Uncompressed frame - pass to decompressor so it
1862                    can update its dictionary if necessary. */
1863                 if (ppp->rcomp->incomp)
1864                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1865                                            skb->len + 2);
1866         }
1867
1868         return skb;
1869
1870  err:
1871         ppp->rstate |= SC_DC_ERROR;
1872         ppp_receive_error(ppp);
1873         return skb;
1874 }
1875
1876 #ifdef CONFIG_PPP_MULTILINK
1877 /*
1878  * Receive a multilink frame.
1879  * We put it on the reconstruction queue and then pull off
1880  * as many completed frames as we can.
1881  */
1882 static void
1883 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1884 {
1885         u32 mask, seq;
1886         struct channel *ch;
1887         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1888
1889         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1890                 goto err;               /* no good, throw it away */
1891
1892         /* Decode sequence number and begin/end bits */
1893         if (ppp->flags & SC_MP_SHORTSEQ) {
1894                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1895                 mask = 0xfff;
1896         } else {
1897                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1898                 mask = 0xffffff;
1899         }
1900         PPP_MP_CB(skb)->BEbits = skb->data[2];
1901         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1902
1903         /*
1904          * Do protocol ID decompression on the first fragment of each packet.
1905          */
1906         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
1907                 *skb_push(skb, 1) = 0;
1908
1909         /*
1910          * Expand sequence number to 32 bits, making it as close
1911          * as possible to ppp->minseq.
1912          */
1913         seq |= ppp->minseq & ~mask;
1914         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1915                 seq += mask + 1;
1916         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1917                 seq -= mask + 1;        /* should never happen */
1918         PPP_MP_CB(skb)->sequence = seq;
1919         pch->lastseq = seq;
1920
1921         /*
1922          * If this packet comes before the next one we were expecting,
1923          * drop it.
1924          */
1925         if (seq_before(seq, ppp->nextseq)) {
1926                 kfree_skb(skb);
1927                 ++ppp->dev->stats.rx_dropped;
1928                 ppp_receive_error(ppp);
1929                 return;
1930         }
1931
1932         /*
1933          * Reevaluate minseq, the minimum over all channels of the
1934          * last sequence number received on each channel.  Because of
1935          * the increasing sequence number rule, we know that any fragment
1936          * before `minseq' which hasn't arrived is never going to arrive.
1937          * The list of channels can't change because we have the receive
1938          * side of the ppp unit locked.
1939          */
1940         list_for_each_entry(ch, &ppp->channels, clist) {
1941                 if (seq_before(ch->lastseq, seq))
1942                         seq = ch->lastseq;
1943         }
1944         if (seq_before(ppp->minseq, seq))
1945                 ppp->minseq = seq;
1946
1947         /* Put the fragment on the reconstruction queue */
1948         ppp_mp_insert(ppp, skb);
1949
1950         /* If the queue is getting long, don't wait any longer for packets
1951            before the start of the queue. */
1952         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1953                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
1954                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
1955                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
1956         }
1957
1958         /* Pull completed packets off the queue and receive them. */
1959         while ((skb = ppp_mp_reconstruct(ppp))) {
1960                 if (pskb_may_pull(skb, 2))
1961                         ppp_receive_nonmp_frame(ppp, skb);
1962                 else {
1963                         ++ppp->dev->stats.rx_length_errors;
1964                         kfree_skb(skb);
1965                         ppp_receive_error(ppp);
1966                 }
1967         }
1968
1969         return;
1970
1971  err:
1972         kfree_skb(skb);
1973         ppp_receive_error(ppp);
1974 }
1975
1976 /*
1977  * Insert a fragment on the MP reconstruction queue.
1978  * The queue is ordered by increasing sequence number.
1979  */
1980 static void
1981 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1982 {
1983         struct sk_buff *p;
1984         struct sk_buff_head *list = &ppp->mrq;
1985         u32 seq = PPP_MP_CB(skb)->sequence;
1986
1987         /* N.B. we don't need to lock the list lock because we have the
1988            ppp unit receive-side lock. */
1989         skb_queue_walk(list, p) {
1990                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
1991                         break;
1992         }
1993         __skb_queue_before(list, p, skb);
1994 }
1995
1996 /*
1997  * Reconstruct a packet from the MP fragment queue.
1998  * We go through increasing sequence numbers until we find a
1999  * complete packet, or we get to the sequence number for a fragment
2000  * which hasn't arrived but might still do so.
2001  */
2002 static struct sk_buff *
2003 ppp_mp_reconstruct(struct ppp *ppp)
2004 {
2005         u32 seq = ppp->nextseq;
2006         u32 minseq = ppp->minseq;
2007         struct sk_buff_head *list = &ppp->mrq;
2008         struct sk_buff *p, *tmp;
2009         struct sk_buff *head, *tail;
2010         struct sk_buff *skb = NULL;
2011         int lost = 0, len = 0;
2012
2013         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2014                 return NULL;
2015         head = list->next;
2016         tail = NULL;
2017         skb_queue_walk_safe(list, p, tmp) {
2018         again:
2019                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2020                         /* this can't happen, anyway ignore the skb */
2021                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2022                                    "seq %u < %u\n",
2023                                    PPP_MP_CB(p)->sequence, seq);
2024                         __skb_unlink(p, list);
2025                         kfree_skb(p);
2026                         continue;
2027                 }
2028                 if (PPP_MP_CB(p)->sequence != seq) {
2029                         u32 oldseq;
2030                         /* Fragment `seq' is missing.  If it is after
2031                            minseq, it might arrive later, so stop here. */
2032                         if (seq_after(seq, minseq))
2033                                 break;
2034                         /* Fragment `seq' is lost, keep going. */
2035                         lost = 1;
2036                         oldseq = seq;
2037                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2038                                 minseq + 1: PPP_MP_CB(p)->sequence;
2039
2040                         if (ppp->debug & 1)
2041                                 netdev_printk(KERN_DEBUG, ppp->dev,
2042                                               "lost frag %u..%u\n",
2043                                               oldseq, seq-1);
2044
2045                         goto again;
2046                 }
2047
2048                 /*
2049                  * At this point we know that all the fragments from
2050                  * ppp->nextseq to seq are either present or lost.
2051                  * Also, there are no complete packets in the queue
2052                  * that have no missing fragments and end before this
2053                  * fragment.
2054                  */
2055
2056                 /* B bit set indicates this fragment starts a packet */
2057                 if (PPP_MP_CB(p)->BEbits & B) {
2058                         head = p;
2059                         lost = 0;
2060                         len = 0;
2061                 }
2062
2063                 len += p->len;
2064
2065                 /* Got a complete packet yet? */
2066                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2067                     (PPP_MP_CB(head)->BEbits & B)) {
2068                         if (len > ppp->mrru + 2) {
2069                                 ++ppp->dev->stats.rx_length_errors;
2070                                 netdev_printk(KERN_DEBUG, ppp->dev,
2071                                               "PPP: reconstructed packet"
2072                                               " is too long (%d)\n", len);
2073                         } else {
2074                                 tail = p;
2075                                 break;
2076                         }
2077                         ppp->nextseq = seq + 1;
2078                 }
2079
2080                 /*
2081                  * If this is the ending fragment of a packet,
2082                  * and we haven't found a complete valid packet yet,
2083                  * we can discard up to and including this fragment.
2084                  */
2085                 if (PPP_MP_CB(p)->BEbits & E) {
2086                         struct sk_buff *tmp2;
2087
2088                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2089                                 if (ppp->debug & 1)
2090                                         netdev_printk(KERN_DEBUG, ppp->dev,
2091                                                       "discarding frag %u\n",
2092                                                       PPP_MP_CB(p)->sequence);
2093                                 __skb_unlink(p, list);
2094                                 kfree_skb(p);
2095                         }
2096                         head = skb_peek(list);
2097                         if (!head)
2098                                 break;
2099                 }
2100                 ++seq;
2101         }
2102
2103         /* If we have a complete packet, copy it all into one skb. */
2104         if (tail != NULL) {
2105                 /* If we have discarded any fragments,
2106                    signal a receive error. */
2107                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2108                         skb_queue_walk_safe(list, p, tmp) {
2109                                 if (p == head)
2110                                         break;
2111                                 if (ppp->debug & 1)
2112                                         netdev_printk(KERN_DEBUG, ppp->dev,
2113                                                       "discarding frag %u\n",
2114                                                       PPP_MP_CB(p)->sequence);
2115                                 __skb_unlink(p, list);
2116                                 kfree_skb(p);
2117                         }
2118
2119                         if (ppp->debug & 1)
2120                                 netdev_printk(KERN_DEBUG, ppp->dev,
2121                                               "  missed pkts %u..%u\n",
2122                                               ppp->nextseq,
2123                                               PPP_MP_CB(head)->sequence-1);
2124                         ++ppp->dev->stats.rx_dropped;
2125                         ppp_receive_error(ppp);
2126                 }
2127
2128                 skb = head;
2129                 if (head != tail) {
2130                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2131                         p = skb_queue_next(list, head);
2132                         __skb_unlink(skb, list);
2133                         skb_queue_walk_from_safe(list, p, tmp) {
2134                                 __skb_unlink(p, list);
2135                                 *fragpp = p;
2136                                 p->next = NULL;
2137                                 fragpp = &p->next;
2138
2139                                 skb->len += p->len;
2140                                 skb->data_len += p->len;
2141                                 skb->truesize += p->len;
2142
2143                                 if (p == tail)
2144                                         break;
2145                         }
2146                 } else {
2147                         __skb_unlink(skb, list);
2148                 }
2149
2150                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2151         }
2152
2153         return skb;
2154 }
2155 #endif /* CONFIG_PPP_MULTILINK */
2156
2157 /*
2158  * Channel interface.
2159  */
2160
2161 /* Create a new, unattached ppp channel. */
2162 int ppp_register_channel(struct ppp_channel *chan)
2163 {
2164         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2165 }
2166
2167 /* Create a new, unattached ppp channel for specified net. */
2168 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2169 {
2170         struct channel *pch;
2171         struct ppp_net *pn;
2172
2173         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2174         if (!pch)
2175                 return -ENOMEM;
2176
2177         pn = ppp_pernet(net);
2178
2179         pch->ppp = NULL;
2180         pch->chan = chan;
2181         pch->chan_net = get_net(net);
2182         chan->ppp = pch;
2183         init_ppp_file(&pch->file, CHANNEL);
2184         pch->file.hdrlen = chan->hdrlen;
2185 #ifdef CONFIG_PPP_MULTILINK
2186         pch->lastseq = -1;
2187 #endif /* CONFIG_PPP_MULTILINK */
2188         init_rwsem(&pch->chan_sem);
2189         spin_lock_init(&pch->downl);
2190         rwlock_init(&pch->upl);
2191
2192         spin_lock_bh(&pn->all_channels_lock);
2193         pch->file.index = ++pn->last_channel_index;
2194         list_add(&pch->list, &pn->new_channels);
2195         atomic_inc(&channel_count);
2196         spin_unlock_bh(&pn->all_channels_lock);
2197
2198         return 0;
2199 }
2200
2201 /*
2202  * Return the index of a channel.
2203  */
2204 int ppp_channel_index(struct ppp_channel *chan)
2205 {
2206         struct channel *pch = chan->ppp;
2207
2208         if (pch)
2209                 return pch->file.index;
2210         return -1;
2211 }
2212
2213 /*
2214  * Return the PPP unit number to which a channel is connected.
2215  */
2216 int ppp_unit_number(struct ppp_channel *chan)
2217 {
2218         struct channel *pch = chan->ppp;
2219         int unit = -1;
2220
2221         if (pch) {
2222                 read_lock_bh(&pch->upl);
2223                 if (pch->ppp)
2224                         unit = pch->ppp->file.index;
2225                 read_unlock_bh(&pch->upl);
2226         }
2227         return unit;
2228 }
2229
2230 /*
2231  * Return the PPP device interface name of a channel.
2232  */
2233 char *ppp_dev_name(struct ppp_channel *chan)
2234 {
2235         struct channel *pch = chan->ppp;
2236         char *name = NULL;
2237
2238         if (pch) {
2239                 read_lock_bh(&pch->upl);
2240                 if (pch->ppp && pch->ppp->dev)
2241                         name = pch->ppp->dev->name;
2242                 read_unlock_bh(&pch->upl);
2243         }
2244         return name;
2245 }
2246
2247
2248 /*
2249  * Disconnect a channel from the generic layer.
2250  * This must be called in process context.
2251  */
2252 void
2253 ppp_unregister_channel(struct ppp_channel *chan)
2254 {
2255         struct channel *pch = chan->ppp;
2256         struct ppp_net *pn;
2257
2258         if (!pch)
2259                 return;         /* should never happen */
2260
2261         chan->ppp = NULL;
2262
2263         /*
2264          * This ensures that we have returned from any calls into the
2265          * the channel's start_xmit or ioctl routine before we proceed.
2266          */
2267         down_write(&pch->chan_sem);
2268         spin_lock_bh(&pch->downl);
2269         pch->chan = NULL;
2270         spin_unlock_bh(&pch->downl);
2271         up_write(&pch->chan_sem);
2272         ppp_disconnect_channel(pch);
2273
2274         pn = ppp_pernet(pch->chan_net);
2275         spin_lock_bh(&pn->all_channels_lock);
2276         list_del(&pch->list);
2277         spin_unlock_bh(&pn->all_channels_lock);
2278         put_net(pch->chan_net);
2279         pch->chan_net = NULL;
2280
2281         pch->file.dead = 1;
2282         wake_up_interruptible(&pch->file.rwait);
2283         if (atomic_dec_and_test(&pch->file.refcnt))
2284                 ppp_destroy_channel(pch);
2285 }
2286
2287 /*
2288  * Callback from a channel when it can accept more to transmit.
2289  * This should be called at BH/softirq level, not interrupt level.
2290  */
2291 void
2292 ppp_output_wakeup(struct ppp_channel *chan)
2293 {
2294         struct channel *pch = chan->ppp;
2295
2296         if (!pch)
2297                 return;
2298         ppp_channel_push(pch);
2299 }
2300
2301 /*
2302  * Compression control.
2303  */
2304
2305 /* Process the PPPIOCSCOMPRESS ioctl. */
2306 static int
2307 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2308 {
2309         int err;
2310         struct compressor *cp, *ocomp;
2311         struct ppp_option_data data;
2312         void *state, *ostate;
2313         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2314
2315         err = -EFAULT;
2316         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2317             (data.length <= CCP_MAX_OPTION_LENGTH &&
2318              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2319                 goto out;
2320         err = -EINVAL;
2321         if (data.length > CCP_MAX_OPTION_LENGTH ||
2322             ccp_option[1] < 2 || ccp_option[1] > data.length)
2323                 goto out;
2324
2325         cp = try_then_request_module(
2326                 find_compressor(ccp_option[0]),
2327                 "ppp-compress-%d", ccp_option[0]);
2328         if (!cp)
2329                 goto out;
2330
2331         err = -ENOBUFS;
2332         if (data.transmit) {
2333                 state = cp->comp_alloc(ccp_option, data.length);
2334                 if (state) {
2335                         ppp_xmit_lock(ppp);
2336                         ppp->xstate &= ~SC_COMP_RUN;
2337                         ocomp = ppp->xcomp;
2338                         ostate = ppp->xc_state;
2339                         ppp->xcomp = cp;
2340                         ppp->xc_state = state;
2341                         ppp_xmit_unlock(ppp);
2342                         if (ostate) {
2343                                 ocomp->comp_free(ostate);
2344                                 module_put(ocomp->owner);
2345                         }
2346                         err = 0;
2347                 } else
2348                         module_put(cp->owner);
2349
2350         } else {
2351                 state = cp->decomp_alloc(ccp_option, data.length);
2352                 if (state) {
2353                         ppp_recv_lock(ppp);
2354                         ppp->rstate &= ~SC_DECOMP_RUN;
2355                         ocomp = ppp->rcomp;
2356                         ostate = ppp->rc_state;
2357                         ppp->rcomp = cp;
2358                         ppp->rc_state = state;
2359                         ppp_recv_unlock(ppp);
2360                         if (ostate) {
2361                                 ocomp->decomp_free(ostate);
2362                                 module_put(ocomp->owner);
2363                         }
2364                         err = 0;
2365                 } else
2366                         module_put(cp->owner);
2367         }
2368
2369  out:
2370         return err;
2371 }
2372
2373 /*
2374  * Look at a CCP packet and update our state accordingly.
2375  * We assume the caller has the xmit or recv path locked.
2376  */
2377 static void
2378 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2379 {
2380         unsigned char *dp;
2381         int len;
2382
2383         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2384                 return; /* no header */
2385         dp = skb->data + 2;
2386
2387         switch (CCP_CODE(dp)) {
2388         case CCP_CONFREQ:
2389
2390                 /* A ConfReq starts negotiation of compression
2391                  * in one direction of transmission,
2392                  * and hence brings it down...but which way?
2393                  *
2394                  * Remember:
2395                  * A ConfReq indicates what the sender would like to receive
2396                  */
2397                 if(inbound)
2398                         /* He is proposing what I should send */
2399                         ppp->xstate &= ~SC_COMP_RUN;
2400                 else
2401                         /* I am proposing to what he should send */
2402                         ppp->rstate &= ~SC_DECOMP_RUN;
2403
2404                 break;
2405
2406         case CCP_TERMREQ:
2407         case CCP_TERMACK:
2408                 /*
2409                  * CCP is going down, both directions of transmission
2410                  */
2411                 ppp->rstate &= ~SC_DECOMP_RUN;
2412                 ppp->xstate &= ~SC_COMP_RUN;
2413                 break;
2414
2415         case CCP_CONFACK:
2416                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2417                         break;
2418                 len = CCP_LENGTH(dp);
2419                 if (!pskb_may_pull(skb, len + 2))
2420                         return;         /* too short */
2421                 dp += CCP_HDRLEN;
2422                 len -= CCP_HDRLEN;
2423                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2424                         break;
2425                 if (inbound) {
2426                         /* we will start receiving compressed packets */
2427                         if (!ppp->rc_state)
2428                                 break;
2429                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2430                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2431                                 ppp->rstate |= SC_DECOMP_RUN;
2432                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2433                         }
2434                 } else {
2435                         /* we will soon start sending compressed packets */
2436                         if (!ppp->xc_state)
2437                                 break;
2438                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2439                                         ppp->file.index, 0, ppp->debug))
2440                                 ppp->xstate |= SC_COMP_RUN;
2441                 }
2442                 break;
2443
2444         case CCP_RESETACK:
2445                 /* reset the [de]compressor */
2446                 if ((ppp->flags & SC_CCP_UP) == 0)
2447                         break;
2448                 if (inbound) {
2449                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2450                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2451                                 ppp->rstate &= ~SC_DC_ERROR;
2452                         }
2453                 } else {
2454                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2455                                 ppp->xcomp->comp_reset(ppp->xc_state);
2456                 }
2457                 break;
2458         }
2459 }
2460
2461 /* Free up compression resources. */
2462 static void
2463 ppp_ccp_closed(struct ppp *ppp)
2464 {
2465         void *xstate, *rstate;
2466         struct compressor *xcomp, *rcomp;
2467
2468         ppp_lock(ppp);
2469         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2470         ppp->xstate = 0;
2471         xcomp = ppp->xcomp;
2472         xstate = ppp->xc_state;
2473         ppp->xc_state = NULL;
2474         ppp->rstate = 0;
2475         rcomp = ppp->rcomp;
2476         rstate = ppp->rc_state;
2477         ppp->rc_state = NULL;
2478         ppp_unlock(ppp);
2479
2480         if (xstate) {
2481                 xcomp->comp_free(xstate);
2482                 module_put(xcomp->owner);
2483         }
2484         if (rstate) {
2485                 rcomp->decomp_free(rstate);
2486                 module_put(rcomp->owner);
2487         }
2488 }
2489
2490 /* List of compressors. */
2491 static LIST_HEAD(compressor_list);
2492 static DEFINE_SPINLOCK(compressor_list_lock);
2493
2494 struct compressor_entry {
2495         struct list_head list;
2496         struct compressor *comp;
2497 };
2498
2499 static struct compressor_entry *
2500 find_comp_entry(int proto)
2501 {
2502         struct compressor_entry *ce;
2503
2504         list_for_each_entry(ce, &compressor_list, list) {
2505                 if (ce->comp->compress_proto == proto)
2506                         return ce;
2507         }
2508         return NULL;
2509 }
2510
2511 /* Register a compressor */
2512 int
2513 ppp_register_compressor(struct compressor *cp)
2514 {
2515         struct compressor_entry *ce;
2516         int ret;
2517         spin_lock(&compressor_list_lock);
2518         ret = -EEXIST;
2519         if (find_comp_entry(cp->compress_proto))
2520                 goto out;
2521         ret = -ENOMEM;
2522         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2523         if (!ce)
2524                 goto out;
2525         ret = 0;
2526         ce->comp = cp;
2527         list_add(&ce->list, &compressor_list);
2528  out:
2529         spin_unlock(&compressor_list_lock);
2530         return ret;
2531 }
2532
2533 /* Unregister a compressor */
2534 void
2535 ppp_unregister_compressor(struct compressor *cp)
2536 {
2537         struct compressor_entry *ce;
2538
2539         spin_lock(&compressor_list_lock);
2540         ce = find_comp_entry(cp->compress_proto);
2541         if (ce && ce->comp == cp) {
2542                 list_del(&ce->list);
2543                 kfree(ce);
2544         }
2545         spin_unlock(&compressor_list_lock);
2546 }
2547
2548 /* Find a compressor. */
2549 static struct compressor *
2550 find_compressor(int type)
2551 {
2552         struct compressor_entry *ce;
2553         struct compressor *cp = NULL;
2554
2555         spin_lock(&compressor_list_lock);
2556         ce = find_comp_entry(type);
2557         if (ce) {
2558                 cp = ce->comp;
2559                 if (!try_module_get(cp->owner))
2560                         cp = NULL;
2561         }
2562         spin_unlock(&compressor_list_lock);
2563         return cp;
2564 }
2565
2566 /*
2567  * Miscelleneous stuff.
2568  */
2569
2570 static void
2571 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2572 {
2573         struct slcompress *vj = ppp->vj;
2574
2575         memset(st, 0, sizeof(*st));
2576         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2577         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2578         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2579         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2580         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2581         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2582         if (!vj)
2583                 return;
2584         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2585         st->vj.vjs_compressed = vj->sls_o_compressed;
2586         st->vj.vjs_searches = vj->sls_o_searches;
2587         st->vj.vjs_misses = vj->sls_o_misses;
2588         st->vj.vjs_errorin = vj->sls_i_error;
2589         st->vj.vjs_tossed = vj->sls_i_tossed;
2590         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2591         st->vj.vjs_compressedin = vj->sls_i_compressed;
2592 }
2593
2594 /*
2595  * Stuff for handling the lists of ppp units and channels
2596  * and for initialization.
2597  */
2598
2599 /*
2600  * Create a new ppp interface unit.  Fails if it can't allocate memory
2601  * or if there is already a unit with the requested number.
2602  * unit == -1 means allocate a new number.
2603  */
2604 static struct ppp *
2605 ppp_create_interface(struct net *net, int unit, int *retp)
2606 {
2607         struct ppp *ppp;
2608         struct ppp_net *pn;
2609         struct net_device *dev = NULL;
2610         int ret = -ENOMEM;
2611         int i;
2612
2613         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2614         if (!dev)
2615                 goto out1;
2616
2617         pn = ppp_pernet(net);
2618
2619         ppp = netdev_priv(dev);
2620         ppp->dev = dev;
2621         ppp->mru = PPP_MRU;
2622         init_ppp_file(&ppp->file, INTERFACE);
2623         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2624         for (i = 0; i < NUM_NP; ++i)
2625                 ppp->npmode[i] = NPMODE_PASS;
2626         INIT_LIST_HEAD(&ppp->channels);
2627         spin_lock_init(&ppp->rlock);
2628         spin_lock_init(&ppp->wlock);
2629 #ifdef CONFIG_PPP_MULTILINK
2630         ppp->minseq = -1;
2631         skb_queue_head_init(&ppp->mrq);
2632 #endif /* CONFIG_PPP_MULTILINK */
2633
2634         /*
2635          * drum roll: don't forget to set
2636          * the net device is belong to
2637          */
2638         dev_net_set(dev, net);
2639
2640         mutex_lock(&pn->all_ppp_mutex);
2641
2642         if (unit < 0) {
2643                 unit = unit_get(&pn->units_idr, ppp);
2644                 if (unit < 0) {
2645                         ret = unit;
2646                         goto out2;
2647                 }
2648         } else {
2649                 ret = -EEXIST;
2650                 if (unit_find(&pn->units_idr, unit))
2651                         goto out2; /* unit already exists */
2652                 /*
2653                  * if caller need a specified unit number
2654                  * lets try to satisfy him, otherwise --
2655                  * he should better ask us for new unit number
2656                  *
2657                  * NOTE: yes I know that returning EEXIST it's not
2658                  * fair but at least pppd will ask us to allocate
2659                  * new unit in this case so user is happy :)
2660                  */
2661                 unit = unit_set(&pn->units_idr, ppp, unit);
2662                 if (unit < 0)
2663                         goto out2;
2664         }
2665
2666         /* Initialize the new ppp unit */
2667         ppp->file.index = unit;
2668         sprintf(dev->name, "ppp%d", unit);
2669
2670         ret = register_netdev(dev);
2671         if (ret != 0) {
2672                 unit_put(&pn->units_idr, unit);
2673                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2674                            dev->name, ret);
2675                 goto out2;
2676         }
2677
2678         ppp->ppp_net = net;
2679
2680         atomic_inc(&ppp_unit_count);
2681         mutex_unlock(&pn->all_ppp_mutex);
2682
2683         *retp = 0;
2684         return ppp;
2685
2686 out2:
2687         mutex_unlock(&pn->all_ppp_mutex);
2688         free_netdev(dev);
2689 out1:
2690         *retp = ret;
2691         return NULL;
2692 }
2693
2694 /*
2695  * Initialize a ppp_file structure.
2696  */
2697 static void
2698 init_ppp_file(struct ppp_file *pf, int kind)
2699 {
2700         pf->kind = kind;
2701         skb_queue_head_init(&pf->xq);
2702         skb_queue_head_init(&pf->rq);
2703         atomic_set(&pf->refcnt, 1);
2704         init_waitqueue_head(&pf->rwait);
2705 }
2706
2707 /*
2708  * Take down a ppp interface unit - called when the owning file
2709  * (the one that created the unit) is closed or detached.
2710  */
2711 static void ppp_shutdown_interface(struct ppp *ppp)
2712 {
2713         struct ppp_net *pn;
2714
2715         pn = ppp_pernet(ppp->ppp_net);
2716         mutex_lock(&pn->all_ppp_mutex);
2717
2718         /* This will call dev_close() for us. */
2719         ppp_lock(ppp);
2720         if (!ppp->closing) {
2721                 ppp->closing = 1;
2722                 ppp_unlock(ppp);
2723                 unregister_netdev(ppp->dev);
2724                 unit_put(&pn->units_idr, ppp->file.index);
2725         } else
2726                 ppp_unlock(ppp);
2727
2728         ppp->file.dead = 1;
2729         ppp->owner = NULL;
2730         wake_up_interruptible(&ppp->file.rwait);
2731
2732         mutex_unlock(&pn->all_ppp_mutex);
2733 }
2734
2735 /*
2736  * Free the memory used by a ppp unit.  This is only called once
2737  * there are no channels connected to the unit and no file structs
2738  * that reference the unit.
2739  */
2740 static void ppp_destroy_interface(struct ppp *ppp)
2741 {
2742         atomic_dec(&ppp_unit_count);
2743
2744         if (!ppp->file.dead || ppp->n_channels) {
2745                 /* "can't happen" */
2746                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2747                            "but dead=%d n_channels=%d !\n",
2748                            ppp, ppp->file.dead, ppp->n_channels);
2749                 return;
2750         }
2751
2752         ppp_ccp_closed(ppp);
2753         if (ppp->vj) {
2754                 slhc_free(ppp->vj);
2755                 ppp->vj = NULL;
2756         }
2757         skb_queue_purge(&ppp->file.xq);
2758         skb_queue_purge(&ppp->file.rq);
2759 #ifdef CONFIG_PPP_MULTILINK
2760         skb_queue_purge(&ppp->mrq);
2761 #endif /* CONFIG_PPP_MULTILINK */
2762 #ifdef CONFIG_PPP_FILTER
2763         kfree(ppp->pass_filter);
2764         ppp->pass_filter = NULL;
2765         kfree(ppp->active_filter);
2766         ppp->active_filter = NULL;
2767 #endif /* CONFIG_PPP_FILTER */
2768
2769         kfree_skb(ppp->xmit_pending);
2770
2771         free_netdev(ppp->dev);
2772 }
2773
2774 /*
2775  * Locate an existing ppp unit.
2776  * The caller should have locked the all_ppp_mutex.
2777  */
2778 static struct ppp *
2779 ppp_find_unit(struct ppp_net *pn, int unit)
2780 {
2781         return unit_find(&pn->units_idr, unit);
2782 }
2783
2784 /*
2785  * Locate an existing ppp channel.
2786  * The caller should have locked the all_channels_lock.
2787  * First we look in the new_channels list, then in the
2788  * all_channels list.  If found in the new_channels list,
2789  * we move it to the all_channels list.  This is for speed
2790  * when we have a lot of channels in use.
2791  */
2792 static struct channel *
2793 ppp_find_channel(struct ppp_net *pn, int unit)
2794 {
2795         struct channel *pch;
2796
2797         list_for_each_entry(pch, &pn->new_channels, list) {
2798                 if (pch->file.index == unit) {
2799                         list_move(&pch->list, &pn->all_channels);
2800                         return pch;
2801                 }
2802         }
2803
2804         list_for_each_entry(pch, &pn->all_channels, list) {
2805                 if (pch->file.index == unit)
2806                         return pch;
2807         }
2808
2809         return NULL;
2810 }
2811
2812 /*
2813  * Connect a PPP channel to a PPP interface unit.
2814  */
2815 static int
2816 ppp_connect_channel(struct channel *pch, int unit)
2817 {
2818         struct ppp *ppp;
2819         struct ppp_net *pn;
2820         int ret = -ENXIO;
2821         int hdrlen;
2822
2823         pn = ppp_pernet(pch->chan_net);
2824
2825         mutex_lock(&pn->all_ppp_mutex);
2826         ppp = ppp_find_unit(pn, unit);
2827         if (!ppp)
2828                 goto out;
2829         write_lock_bh(&pch->upl);
2830         ret = -EINVAL;
2831         if (pch->ppp)
2832                 goto outl;
2833
2834         ppp_lock(ppp);
2835         if (pch->file.hdrlen > ppp->file.hdrlen)
2836                 ppp->file.hdrlen = pch->file.hdrlen;
2837         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2838         if (hdrlen > ppp->dev->hard_header_len)
2839                 ppp->dev->hard_header_len = hdrlen;
2840         list_add_tail(&pch->clist, &ppp->channels);
2841         ++ppp->n_channels;
2842         pch->ppp = ppp;
2843         atomic_inc(&ppp->file.refcnt);
2844         ppp_unlock(ppp);
2845         ret = 0;
2846
2847  outl:
2848         write_unlock_bh(&pch->upl);
2849  out:
2850         mutex_unlock(&pn->all_ppp_mutex);
2851         return ret;
2852 }
2853
2854 /*
2855  * Disconnect a channel from its ppp unit.
2856  */
2857 static int
2858 ppp_disconnect_channel(struct channel *pch)
2859 {
2860         struct ppp *ppp;
2861         int err = -EINVAL;
2862
2863         write_lock_bh(&pch->upl);
2864         ppp = pch->ppp;
2865         pch->ppp = NULL;
2866         write_unlock_bh(&pch->upl);
2867         if (ppp) {
2868                 /* remove it from the ppp unit's list */
2869                 ppp_lock(ppp);
2870                 list_del(&pch->clist);
2871                 if (--ppp->n_channels == 0)
2872                         wake_up_interruptible(&ppp->file.rwait);
2873                 ppp_unlock(ppp);
2874                 if (atomic_dec_and_test(&ppp->file.refcnt))
2875                         ppp_destroy_interface(ppp);
2876                 err = 0;
2877         }
2878         return err;
2879 }
2880
2881 /*
2882  * Free up the resources used by a ppp channel.
2883  */
2884 static void ppp_destroy_channel(struct channel *pch)
2885 {
2886         atomic_dec(&channel_count);
2887
2888         if (!pch->file.dead) {
2889                 /* "can't happen" */
2890                 pr_err("ppp: destroying undead channel %p !\n", pch);
2891                 return;
2892         }
2893         skb_queue_purge(&pch->file.xq);
2894         skb_queue_purge(&pch->file.rq);
2895         kfree(pch);
2896 }
2897
2898 static void __exit ppp_cleanup(void)
2899 {
2900         /* should never happen */
2901         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2902                 pr_err("PPP: removing module but units remain!\n");
2903         unregister_chrdev(PPP_MAJOR, "ppp");
2904         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2905         class_destroy(ppp_class);
2906         unregister_pernet_device(&ppp_net_ops);
2907 }
2908
2909 /*
2910  * Units handling. Caller must protect concurrent access
2911  * by holding all_ppp_mutex
2912  */
2913
2914 static int __unit_alloc(struct idr *p, void *ptr, int n)
2915 {
2916         int unit, err;
2917
2918 again:
2919         if (!idr_pre_get(p, GFP_KERNEL)) {
2920                 pr_err("PPP: No free memory for idr\n");
2921                 return -ENOMEM;
2922         }
2923
2924         err = idr_get_new_above(p, ptr, n, &unit);
2925         if (err < 0) {
2926                 if (err == -EAGAIN)
2927                         goto again;
2928                 return err;
2929         }
2930
2931         return unit;
2932 }
2933
2934 /* associate pointer with specified number */
2935 static int unit_set(struct idr *p, void *ptr, int n)
2936 {
2937         int unit;
2938
2939         unit = __unit_alloc(p, ptr, n);
2940         if (unit < 0)
2941                 return unit;
2942         else if (unit != n) {
2943                 idr_remove(p, unit);
2944                 return -EINVAL;
2945         }
2946
2947         return unit;
2948 }
2949
2950 /* get new free unit number and associate pointer with it */
2951 static int unit_get(struct idr *p, void *ptr)
2952 {
2953         return __unit_alloc(p, ptr, 0);
2954 }
2955
2956 /* put unit number back to a pool */
2957 static void unit_put(struct idr *p, int n)
2958 {
2959         idr_remove(p, n);
2960 }
2961
2962 /* get pointer associated with the number */
2963 static void *unit_find(struct idr *p, int n)
2964 {
2965         return idr_find(p, n);
2966 }
2967
2968 /* Module/initialization stuff */
2969
2970 module_init(ppp_init);
2971 module_exit(ppp_cleanup);
2972
2973 EXPORT_SYMBOL(ppp_register_net_channel);
2974 EXPORT_SYMBOL(ppp_register_channel);
2975 EXPORT_SYMBOL(ppp_unregister_channel);
2976 EXPORT_SYMBOL(ppp_channel_index);
2977 EXPORT_SYMBOL(ppp_unit_number);
2978 EXPORT_SYMBOL(ppp_dev_name);
2979 EXPORT_SYMBOL(ppp_input);
2980 EXPORT_SYMBOL(ppp_input_error);
2981 EXPORT_SYMBOL(ppp_output_wakeup);
2982 EXPORT_SYMBOL(ppp_register_compressor);
2983 EXPORT_SYMBOL(ppp_unregister_compressor);
2984 MODULE_LICENSE("GPL");
2985 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
2986 MODULE_ALIAS("devname:ppp");