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