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