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