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/smp_lock.h>
  44 #include <linux/spinlock.h>
  45 #include <linux/rwsem.h>
  46 #include <linux/stddef.h>
  47 #include <linux/device.h>
  48 #include <linux/mutex.h>
  49 #include <linux/slab.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 atomic_t ppp_unit_count = ATOMIC_INIT(0);
 184 static atomic_t channel_count = ATOMIC_INIT(0);
 185
 186 /* per-net private data for this module */
 187 static int ppp_net_id __read_mostly;
 188 struct ppp_net {
 189         /* units to ppp mapping */
 190         struct idr units_idr;
 191
 192         /*
 193          * all_ppp_mutex protects the units_idr mapping.
 194          * It also ensures that finding a ppp unit in the units_idr
 195          * map and updating its file.refcnt field is atomic.
 196          */
 197         struct mutex all_ppp_mutex;
 198
 199         /* channels */
 200         struct list_head all_channels;
 201         struct list_head new_channels;
 202         int last_channel_index;
 203
 204         /*
 205          * all_channels_lock protects all_channels and
 206          * last_channel_index, and the atomicity of find
 207          * a channel and updating its file.refcnt field.
 208          */
 209         spinlock_t all_channels_lock;
 210 };
 211
 212 /* Get the PPP protocol number from a skb */
 213 #define PPP_PROTO(skb)  (((skb)->data[0] << 8) + (skb)->data[1])
 214
 215 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 216 #define PPP_MAX_RQLEN   32
 217
 218 /*
 219  * Maximum number of multilink fragments queued up.
 220  * This has to be large enough to cope with the maximum latency of
 221  * the slowest channel relative to the others.  Strictly it should
 222  * depend on the number of channels and their characteristics.
 223  */
 224 #define PPP_MP_MAX_QLEN 128
 225
 226 /* Multilink header bits. */
 227 #define B       0x80            /* this fragment begins a packet */
 228 #define E       0x40            /* this fragment ends a packet */
 229
 230 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 231 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 232 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 233
 234 /* Prototypes. */
 235 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 236                         struct file *file, unsigned int cmd, unsigned long arg);
 237 static void ppp_xmit_process(struct ppp *ppp);
 238 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 239 static void ppp_push(struct ppp *ppp);
 240 static void ppp_channel_push(struct channel *pch);
 241 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 242                               struct channel *pch);
 243 static void ppp_receive_error(struct ppp *ppp);
 244 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 245 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 246                                             struct sk_buff *skb);
 247 #ifdef CONFIG_PPP_MULTILINK
 248 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 249                                 struct channel *pch);
 250 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 251 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 252 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 253 #endif /* CONFIG_PPP_MULTILINK */
 254 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 255 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 256 static void ppp_ccp_closed(struct ppp *ppp);
 257 static struct compressor *find_compressor(int type);
 258 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 259 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 260 static void init_ppp_file(struct ppp_file *pf, int kind);
 261 static void ppp_shutdown_interface(struct ppp *ppp);
 262 static void ppp_destroy_interface(struct ppp *ppp);
 263 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 264 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 265 static int ppp_connect_channel(struct channel *pch, int unit);
 266 static int ppp_disconnect_channel(struct channel *pch);
 267 static void ppp_destroy_channel(struct channel *pch);
 268 static int unit_get(struct idr *p, void *ptr);
 269 static int unit_set(struct idr *p, void *ptr, int n);
 270 static void unit_put(struct idr *p, int n);
 271 static void *unit_find(struct idr *p, int n);
 272
 273 static struct class *ppp_class;
 274
 275 /* per net-namespace data */
 276 static inline struct ppp_net *ppp_pernet(struct net *net)
 277 {
 278         BUG_ON(!net);
 279
 280         return net_generic(net, ppp_net_id);
 281 }
 282
 283 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 284 static inline int proto_to_npindex(int proto)
 285 {
 286         switch (proto) {
 287         case PPP_IP:
 288                 return NP_IP;
 289         case PPP_IPV6:
 290                 return NP_IPV6;
 291         case PPP_IPX:
 292                 return NP_IPX;
 293         case PPP_AT:
 294                 return NP_AT;
 295         case PPP_MPLS_UC:
 296                 return NP_MPLS_UC;
 297         case PPP_MPLS_MC:
 298                 return NP_MPLS_MC;
 299         }
 300         return -EINVAL;
 301 }
 302
 303 /* Translates an NP index into a PPP protocol number */
 304 static const int npindex_to_proto[NUM_NP] = {
 305         PPP_IP,
 306         PPP_IPV6,
 307         PPP_IPX,
 308         PPP_AT,
 309         PPP_MPLS_UC,
 310         PPP_MPLS_MC,
 311 };
 312
 313 /* Translates an ethertype into an NP index */
 314 static inline int ethertype_to_npindex(int ethertype)
 315 {
 316         switch (ethertype) {
 317         case ETH_P_IP:
 318                 return NP_IP;
 319         case ETH_P_IPV6:
 320                 return NP_IPV6;
 321         case ETH_P_IPX:
 322                 return NP_IPX;
 323         case ETH_P_PPPTALK:
 324         case ETH_P_ATALK:
 325                 return NP_AT;
 326         case ETH_P_MPLS_UC:
 327                 return NP_MPLS_UC;
 328         case ETH_P_MPLS_MC:
 329                 return NP_MPLS_MC;
 330         }
 331         return -1;
 332 }
 333
 334 /* Translates an NP index into an ethertype */
 335 static const int npindex_to_ethertype[NUM_NP] = {
 336         ETH_P_IP,
 337         ETH_P_IPV6,
 338         ETH_P_IPX,
 339         ETH_P_PPPTALK,
 340         ETH_P_MPLS_UC,
 341         ETH_P_MPLS_MC,
 342 };
 343
 344 /*
 345  * Locking shorthand.
 346  */
 347 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 348 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 349 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 350 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 351 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 352                                      ppp_recv_lock(ppp); } while (0)
 353 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 354                                      ppp_xmit_unlock(ppp); } while (0)
 355
 356 /*
 357  * /dev/ppp device routines.
 358  * The /dev/ppp device is used by pppd to control the ppp unit.
 359  * It supports the read, write, ioctl and poll functions.
 360  * Open instances of /dev/ppp can be in one of three states:
 361  * unattached, attached to a ppp unit, or attached to a ppp channel.
 362  */
 363 static int ppp_open(struct inode *inode, struct file *file)
 364 {
 365         cycle_kernel_lock();
 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                 lock_kernel();
 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                         printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
 596                                atomic_long_read(&file->f_count));
 597                 unlock_kernel();
 598                 return err;
 599         }
 600
 601         if (pf->kind == CHANNEL) {
 602                 struct channel *pch;
 603                 struct ppp_channel *chan;
 604
 605                 lock_kernel();
 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                 unlock_kernel();
 628                 return err;
 629         }
 630
 631         if (pf->kind != INTERFACE) {
 632                 /* can't happen */
 633                 printk(KERN_ERR "PPP: not interface or channel??\n");
 634                 return -EINVAL;
 635         }
 636
 637         lock_kernel();
 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                         printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
 708                         err = -ENOMEM;
 709                         break;
 710                 }
 711                 ppp_lock(ppp);
 712                 if (ppp->vj)
 713                         slhc_free(ppp->vj);
 714                 ppp->vj = vj;
 715                 ppp_unlock(ppp);
 716                 err = 0;
 717                 break;
 718
 719         case PPPIOCGNPMODE:
 720         case PPPIOCSNPMODE:
 721                 if (copy_from_user(&npi, argp, sizeof(npi)))
 722                         break;
 723                 err = proto_to_npindex(npi.protocol);
 724                 if (err < 0)
 725                         break;
 726                 i = err;
 727                 if (cmd == PPPIOCGNPMODE) {
 728                         err = -EFAULT;
 729                         npi.mode = ppp->npmode[i];
 730                         if (copy_to_user(argp, &npi, sizeof(npi)))
 731                                 break;
 732                 } else {
 733                         ppp->npmode[i] = npi.mode;
 734                         /* we may be able to transmit more packets now (??) */
 735                         netif_wake_queue(ppp->dev);
 736                 }
 737                 err = 0;
 738                 break;
 739
 740 #ifdef CONFIG_PPP_FILTER
 741         case PPPIOCSPASS:
 742         {
 743                 struct sock_filter *code;
 744                 err = get_filter(argp, &code);
 745                 if (err >= 0) {
 746                         ppp_lock(ppp);
 747                         kfree(ppp->pass_filter);
 748                         ppp->pass_filter = code;
 749                         ppp->pass_len = err;
 750                         ppp_unlock(ppp);
 751                         err = 0;
 752                 }
 753                 break;
 754         }
 755         case PPPIOCSACTIVE:
 756         {
 757                 struct sock_filter *code;
 758                 err = get_filter(argp, &code);
 759                 if (err >= 0) {
 760                         ppp_lock(ppp);
 761                         kfree(ppp->active_filter);
 762                         ppp->active_filter = code;
 763                         ppp->active_len = err;
 764                         ppp_unlock(ppp);
 765                         err = 0;
 766                 }
 767                 break;
 768         }
 769 #endif /* CONFIG_PPP_FILTER */
 770
 771 #ifdef CONFIG_PPP_MULTILINK
 772         case PPPIOCSMRRU:
 773                 if (get_user(val, p))
 774                         break;
 775                 ppp_recv_lock(ppp);
 776                 ppp->mrru = val;
 777                 ppp_recv_unlock(ppp);
 778                 err = 0;
 779                 break;
 780 #endif /* CONFIG_PPP_MULTILINK */
 781
 782         default:
 783                 err = -ENOTTY;
 784         }
 785         unlock_kernel();
 786         return err;
 787 }
 788
 789 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 790                         struct file *file, unsigned int cmd, unsigned long arg)
 791 {
 792         int unit, err = -EFAULT;
 793         struct ppp *ppp;
 794         struct channel *chan;
 795         struct ppp_net *pn;
 796         int __user *p = (int __user *)arg;
 797
 798         lock_kernel();
 799         switch (cmd) {
 800         case PPPIOCNEWUNIT:
 801                 /* Create a new ppp unit */
 802                 if (get_user(unit, p))
 803                         break;
 804                 ppp = ppp_create_interface(net, unit, &err);
 805                 if (!ppp)
 806                         break;
 807                 file->private_data = &ppp->file;
 808                 ppp->owner = file;
 809                 err = -EFAULT;
 810                 if (put_user(ppp->file.index, p))
 811                         break;
 812                 err = 0;
 813                 break;
 814
 815         case PPPIOCATTACH:
 816                 /* Attach to an existing ppp unit */
 817                 if (get_user(unit, p))
 818                         break;
 819                 err = -ENXIO;
 820                 pn = ppp_pernet(net);
 821                 mutex_lock(&pn->all_ppp_mutex);
 822                 ppp = ppp_find_unit(pn, unit);
 823                 if (ppp) {
 824                         atomic_inc(&ppp->file.refcnt);
 825                         file->private_data = &ppp->file;
 826                         err = 0;
 827                 }
 828                 mutex_unlock(&pn->all_ppp_mutex);
 829                 break;
 830
 831         case PPPIOCATTCHAN:
 832                 if (get_user(unit, p))
 833                         break;
 834                 err = -ENXIO;
 835                 pn = ppp_pernet(net);
 836                 spin_lock_bh(&pn->all_channels_lock);
 837                 chan = ppp_find_channel(pn, unit);
 838                 if (chan) {
 839                         atomic_inc(&chan->file.refcnt);
 840                         file->private_data = &chan->file;
 841                         err = 0;
 842                 }
 843                 spin_unlock_bh(&pn->all_channels_lock);
 844                 break;
 845
 846         default:
 847                 err = -ENOTTY;
 848         }
 849         unlock_kernel();
 850         return err;
 851 }
 852
 853 static const struct file_operations ppp_device_fops = {
 854         .owner          = THIS_MODULE,
 855         .read           = ppp_read,
 856         .write          = ppp_write,
 857         .poll           = ppp_poll,
 858         .unlocked_ioctl = ppp_ioctl,
 859         .open           = ppp_open,
 860         .release        = ppp_release
 861 };
 862
 863 static __net_init int ppp_init_net(struct net *net)
 864 {
 865         struct ppp_net *pn = net_generic(net, ppp_net_id);
 866
 867         idr_init(&pn->units_idr);
 868         mutex_init(&pn->all_ppp_mutex);
 869
 870         INIT_LIST_HEAD(&pn->all_channels);
 871         INIT_LIST_HEAD(&pn->new_channels);
 872
 873         spin_lock_init(&pn->all_channels_lock);
 874
 875         return 0;
 876 }
 877
 878 static __net_exit void ppp_exit_net(struct net *net)
 879 {
 880         struct ppp_net *pn = net_generic(net, ppp_net_id);
 881
 882         idr_destroy(&pn->units_idr);
 883 }
 884
 885 static struct pernet_operations ppp_net_ops = {
 886         .init = ppp_init_net,
 887         .exit = ppp_exit_net,
 888         .id   = &ppp_net_id,
 889         .size = sizeof(struct ppp_net),
 890 };
 891
 892 #define PPP_MAJOR       108
 893
 894 /* Called at boot time if ppp is compiled into the kernel,
 895    or at module load time (from init_module) if compiled as a module. */
 896 static int __init ppp_init(void)
 897 {
 898         int err;
 899
 900         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
 901
 902         err = register_pernet_device(&ppp_net_ops);
 903         if (err) {
 904                 printk(KERN_ERR "failed to register PPP pernet device (%d)\n", err);
 905                 goto out;
 906         }
 907
 908         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 909         if (err) {
 910                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
 911                 goto out_net;
 912         }
 913
 914         ppp_class = class_create(THIS_MODULE, "ppp");
 915         if (IS_ERR(ppp_class)) {
 916                 err = PTR_ERR(ppp_class);
 917                 goto out_chrdev;
 918         }
 919
 920         /* not a big deal if we fail here :-) */
 921         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 922
 923         return 0;
 924
 925 out_chrdev:
 926         unregister_chrdev(PPP_MAJOR, "ppp");
 927 out_net:
 928         unregister_pernet_device(&ppp_net_ops);
 929 out:
 930         return err;
 931 }
 932
 933 /*
 934  * Network interface unit routines.
 935  */
 936 static netdev_tx_t
 937 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 938 {
 939         struct ppp *ppp = netdev_priv(dev);
 940         int npi, proto;
 941         unsigned char *pp;
 942
 943         npi = ethertype_to_npindex(ntohs(skb->protocol));
 944         if (npi < 0)
 945                 goto outf;
 946
 947         /* Drop, accept or reject the packet */
 948         switch (ppp->npmode[npi]) {
 949         case NPMODE_PASS:
 950                 break;
 951         case NPMODE_QUEUE:
 952                 /* it would be nice to have a way to tell the network
 953                    system to queue this one up for later. */
 954                 goto outf;
 955         case NPMODE_DROP:
 956         case NPMODE_ERROR:
 957                 goto outf;
 958         }
 959
 960         /* Put the 2-byte PPP protocol number on the front,
 961            making sure there is room for the address and control fields. */
 962         if (skb_cow_head(skb, PPP_HDRLEN))
 963                 goto outf;
 964
 965         pp = skb_push(skb, 2);
 966         proto = npindex_to_proto[npi];
 967         pp[0] = proto >> 8;
 968         pp[1] = proto;
 969
 970         netif_stop_queue(dev);
 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         }
1066         ppp_xmit_unlock(ppp);
1067 }
1068
1069 static inline struct sk_buff *
1070 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1071 {
1072         struct sk_buff *new_skb;
1073         int len;
1074         int new_skb_size = ppp->dev->mtu +
1075                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1076         int compressor_skb_size = ppp->dev->mtu +
1077                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1078         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1079         if (!new_skb) {
1080                 if (net_ratelimit())
1081                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1082                 return NULL;
1083         }
1084         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1085                 skb_reserve(new_skb,
1086                             ppp->dev->hard_header_len - PPP_HDRLEN);
1087
1088         /* compressor still expects A/C bytes in hdr */
1089         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1090                                    new_skb->data, skb->len + 2,
1091                                    compressor_skb_size);
1092         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1093                 kfree_skb(skb);
1094                 skb = new_skb;
1095                 skb_put(skb, len);
1096                 skb_pull(skb, 2);       /* pull off A/C bytes */
1097         } else if (len == 0) {
1098                 /* didn't compress, or CCP not up yet */
1099                 kfree_skb(new_skb);
1100                 new_skb = skb;
1101         } else {
1102                 /*
1103                  * (len < 0)
1104                  * MPPE requires that we do not send unencrypted
1105                  * frames.  The compressor will return -1 if we
1106                  * should drop the frame.  We cannot simply test
1107                  * the compress_proto because MPPE and MPPC share
1108                  * the same number.
1109                  */
1110                 if (net_ratelimit())
1111                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1112                 kfree_skb(skb);
1113                 kfree_skb(new_skb);
1114                 new_skb = NULL;
1115         }
1116         return new_skb;
1117 }
1118
1119 /*
1120  * Compress and send a frame.
1121  * The caller should have locked the xmit path,
1122  * and xmit_pending should be 0.
1123  */
1124 static void
1125 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1126 {
1127         int proto = PPP_PROTO(skb);
1128         struct sk_buff *new_skb;
1129         int len;
1130         unsigned char *cp;
1131
1132         if (proto < 0x8000) {
1133 #ifdef CONFIG_PPP_FILTER
1134                 /* check if we should pass this packet */
1135                 /* the filter instructions are constructed assuming
1136                    a four-byte PPP header on each packet */
1137                 *skb_push(skb, 2) = 1;
1138                 if (ppp->pass_filter &&
1139                     sk_run_filter(skb, ppp->pass_filter,
1140                                   ppp->pass_len) == 0) {
1141                         if (ppp->debug & 1)
1142                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1143                         kfree_skb(skb);
1144                         return;
1145                 }
1146                 /* if this packet passes the active filter, record the time */
1147                 if (!(ppp->active_filter &&
1148                       sk_run_filter(skb, ppp->active_filter,
1149                                     ppp->active_len) == 0))
1150                         ppp->last_xmit = jiffies;
1151                 skb_pull(skb, 2);
1152 #else
1153                 /* for data packets, record the time */
1154                 ppp->last_xmit = jiffies;
1155 #endif /* CONFIG_PPP_FILTER */
1156         }
1157
1158         ++ppp->dev->stats.tx_packets;
1159         ppp->dev->stats.tx_bytes += skb->len - 2;
1160
1161         switch (proto) {
1162         case PPP_IP:
1163                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1164                         break;
1165                 /* try to do VJ TCP header compression */
1166                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1167                                     GFP_ATOMIC);
1168                 if (!new_skb) {
1169                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1170                         goto drop;
1171                 }
1172                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1173                 cp = skb->data + 2;
1174                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1175                                     new_skb->data + 2, &cp,
1176                                     !(ppp->flags & SC_NO_TCP_CCID));
1177                 if (cp == skb->data + 2) {
1178                         /* didn't compress */
1179                         kfree_skb(new_skb);
1180                 } else {
1181                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1182                                 proto = PPP_VJC_COMP;
1183                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1184                         } else {
1185                                 proto = PPP_VJC_UNCOMP;
1186                                 cp[0] = skb->data[2];
1187                         }
1188                         kfree_skb(skb);
1189                         skb = new_skb;
1190                         cp = skb_put(skb, len + 2);
1191                         cp[0] = 0;
1192                         cp[1] = proto;
1193                 }
1194                 break;
1195
1196         case PPP_CCP:
1197                 /* peek at outbound CCP frames */
1198                 ppp_ccp_peek(ppp, skb, 0);
1199                 break;
1200         }
1201
1202         /* try to do packet compression */
1203         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1204             proto != PPP_LCP && proto != PPP_CCP) {
1205                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1206                         if (net_ratelimit())
1207                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1208                         goto drop;
1209                 }
1210                 skb = pad_compress_skb(ppp, skb);
1211                 if (!skb)
1212                         goto drop;
1213         }
1214
1215         /*
1216          * If we are waiting for traffic (demand dialling),
1217          * queue it up for pppd to receive.
1218          */
1219         if (ppp->flags & SC_LOOP_TRAFFIC) {
1220                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1221                         goto drop;
1222                 skb_queue_tail(&ppp->file.rq, skb);
1223                 wake_up_interruptible(&ppp->file.rwait);
1224                 return;
1225         }
1226
1227         ppp->xmit_pending = skb;
1228         ppp_push(ppp);
1229         return;
1230
1231  drop:
1232         kfree_skb(skb);
1233         ++ppp->dev->stats.tx_errors;
1234 }
1235
1236 /*
1237  * Try to send the frame in xmit_pending.
1238  * The caller should have the xmit path locked.
1239  */
1240 static void
1241 ppp_push(struct ppp *ppp)
1242 {
1243         struct list_head *list;
1244         struct channel *pch;
1245         struct sk_buff *skb = ppp->xmit_pending;
1246
1247         if (!skb)
1248                 return;
1249
1250         list = &ppp->channels;
1251         if (list_empty(list)) {
1252                 /* nowhere to send the packet, just drop it */
1253                 ppp->xmit_pending = NULL;
1254                 kfree_skb(skb);
1255                 return;
1256         }
1257
1258         if ((ppp->flags & SC_MULTILINK) == 0) {
1259                 /* not doing multilink: send it down the first channel */
1260                 list = list->next;
1261                 pch = list_entry(list, struct channel, clist);
1262
1263                 spin_lock_bh(&pch->downl);
1264                 if (pch->chan) {
1265                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1266                                 ppp->xmit_pending = NULL;
1267                 } else {
1268                         /* channel got unregistered */
1269                         kfree_skb(skb);
1270                         ppp->xmit_pending = NULL;
1271                 }
1272                 spin_unlock_bh(&pch->downl);
1273                 return;
1274         }
1275
1276 #ifdef CONFIG_PPP_MULTILINK
1277         /* Multilink: fragment the packet over as many links
1278            as can take the packet at the moment. */
1279         if (!ppp_mp_explode(ppp, skb))
1280                 return;
1281 #endif /* CONFIG_PPP_MULTILINK */
1282
1283         ppp->xmit_pending = NULL;
1284         kfree_skb(skb);
1285 }
1286
1287 #ifdef CONFIG_PPP_MULTILINK
1288 /*
1289  * Divide a packet to be transmitted into fragments and
1290  * send them out the individual links.
1291  */
1292 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1293 {
1294         int len, totlen;
1295         int i, bits, hdrlen, mtu;
1296         int flen;
1297         int navail, nfree, nzero;
1298         int nbigger;
1299         int totspeed;
1300         int totfree;
1301         unsigned char *p, *q;
1302         struct list_head *list;
1303         struct channel *pch;
1304         struct sk_buff *frag;
1305         struct ppp_channel *chan;
1306
1307         totspeed = 0; /*total bitrate of the bundle*/
1308         nfree = 0; /* # channels which have no packet already queued */
1309         navail = 0; /* total # of usable channels (not deregistered) */
1310         nzero = 0; /* number of channels with zero speed associated*/
1311         totfree = 0; /*total # of channels available and
1312                                   *having no queued packets before
1313                                   *starting the fragmentation*/
1314
1315         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1316         i = 0;
1317         list_for_each_entry(pch, &ppp->channels, clist) {
1318                 navail += pch->avail = (pch->chan != NULL);
1319                 pch->speed = pch->chan->speed;
1320                 if (pch->avail) {
1321                         if (skb_queue_empty(&pch->file.xq) ||
1322                                 !pch->had_frag) {
1323                                         if (pch->speed == 0)
1324                                                 nzero++;
1325                                         else
1326                                                 totspeed += pch->speed;
1327
1328                                         pch->avail = 2;
1329                                         ++nfree;
1330                                         ++totfree;
1331                                 }
1332                         if (!pch->had_frag && i < ppp->nxchan)
1333                                 ppp->nxchan = i;
1334                 }
1335                 ++i;
1336         }
1337         /*
1338          * Don't start sending this packet unless at least half of
1339          * the channels are free.  This gives much better TCP
1340          * performance if we have a lot of channels.
1341          */
1342         if (nfree == 0 || nfree < navail / 2)
1343                 return 0; /* can't take now, leave it in xmit_pending */
1344
1345         /* Do protocol field compression (XXX this should be optional) */
1346         p = skb->data;
1347         len = skb->len;
1348         if (*p == 0) {
1349                 ++p;
1350                 --len;
1351         }
1352
1353         totlen = len;
1354         nbigger = len % nfree;
1355
1356         /* skip to the channel after the one we last used
1357            and start at that one */
1358         list = &ppp->channels;
1359         for (i = 0; i < ppp->nxchan; ++i) {
1360                 list = list->next;
1361                 if (list == &ppp->channels) {
1362                         i = 0;
1363                         break;
1364                 }
1365         }
1366
1367         /* create a fragment for each channel */
1368         bits = B;
1369         while (len > 0) {
1370                 list = list->next;
1371                 if (list == &ppp->channels) {
1372                         i = 0;
1373                         continue;
1374                 }
1375                 pch = list_entry(list, struct channel, clist);
1376                 ++i;
1377                 if (!pch->avail)
1378                         continue;
1379
1380                 /*
1381                  * Skip this channel if it has a fragment pending already and
1382                  * we haven't given a fragment to all of the free channels.
1383                  */
1384                 if (pch->avail == 1) {
1385                         if (nfree > 0)
1386                                 continue;
1387                 } else {
1388                         pch->avail = 1;
1389                 }
1390
1391                 /* check the channel's mtu and whether it is still attached. */
1392                 spin_lock_bh(&pch->downl);
1393                 if (pch->chan == NULL) {
1394                         /* can't use this channel, it's being deregistered */
1395                         if (pch->speed == 0)
1396                                 nzero--;
1397                         else
1398                                 totspeed -= pch->speed;
1399
1400                         spin_unlock_bh(&pch->downl);
1401                         pch->avail = 0;
1402                         totlen = len;
1403                         totfree--;
1404                         nfree--;
1405                         if (--navail == 0)
1406                                 break;
1407                         continue;
1408                 }
1409
1410                 /*
1411                 *if the channel speed is not set divide
1412                 *the packet evenly among the free channels;
1413                 *otherwise divide it according to the speed
1414                 *of the channel we are going to transmit on
1415                 */
1416                 flen = len;
1417                 if (nfree > 0) {
1418                         if (pch->speed == 0) {
1419                                 flen = totlen/nfree;
1420                                 if (nbigger > 0) {
1421                                         flen++;
1422                                         nbigger--;
1423                                 }
1424                         } else {
1425                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1426                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1427                                 if (nbigger > 0) {
1428                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1429                                         nbigger -= ((totfree - nzero)*pch->speed)/
1430                                                         totspeed;
1431                                 }
1432                         }
1433                         nfree--;
1434                 }
1435
1436                 /*
1437                  *check if we are on the last channel or
1438                  *we exceded the lenght of the data to
1439                  *fragment
1440                  */
1441                 if ((nfree <= 0) || (flen > len))
1442                         flen = len;
1443                 /*
1444                  *it is not worth to tx on slow channels:
1445                  *in that case from the resulting flen according to the
1446                  *above formula will be equal or less than zero.
1447                  *Skip the channel in this case
1448                  */
1449                 if (flen <= 0) {
1450                         pch->avail = 2;
1451                         spin_unlock_bh(&pch->downl);
1452                         continue;
1453                 }
1454
1455                 mtu = pch->chan->mtu - hdrlen;
1456                 if (mtu < 4)
1457                         mtu = 4;
1458                 if (flen > mtu)
1459                         flen = mtu;
1460                 if (flen == len)
1461                         bits |= E;
1462                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1463                 if (!frag)
1464                         goto noskb;
1465                 q = skb_put(frag, flen + hdrlen);
1466
1467                 /* make the MP header */
1468                 q[0] = PPP_MP >> 8;
1469                 q[1] = PPP_MP;
1470                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1471                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1472                         q[3] = ppp->nxseq;
1473                 } else {
1474                         q[2] = bits;
1475                         q[3] = ppp->nxseq >> 16;
1476                         q[4] = ppp->nxseq >> 8;
1477                         q[5] = ppp->nxseq;
1478                 }
1479
1480                 memcpy(q + hdrlen, p, flen);
1481
1482                 /* try to send it down the channel */
1483                 chan = pch->chan;
1484                 if (!skb_queue_empty(&pch->file.xq) ||
1485                         !chan->ops->start_xmit(chan, frag))
1486                         skb_queue_tail(&pch->file.xq, frag);
1487                 pch->had_frag = 1;
1488                 p += flen;
1489                 len -= flen;
1490                 ++ppp->nxseq;
1491                 bits = 0;
1492                 spin_unlock_bh(&pch->downl);
1493         }
1494         ppp->nxchan = i;
1495
1496         return 1;
1497
1498  noskb:
1499         spin_unlock_bh(&pch->downl);
1500         if (ppp->debug & 1)
1501                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1502         ++ppp->dev->stats.tx_errors;
1503         ++ppp->nxseq;
1504         return 1;       /* abandon the frame */
1505 }
1506 #endif /* CONFIG_PPP_MULTILINK */
1507
1508 /*
1509  * Try to send data out on a channel.
1510  */
1511 static void
1512 ppp_channel_push(struct channel *pch)
1513 {
1514         struct sk_buff *skb;
1515         struct ppp *ppp;
1516
1517         spin_lock_bh(&pch->downl);
1518         if (pch->chan) {
1519                 while (!skb_queue_empty(&pch->file.xq)) {
1520                         skb = skb_dequeue(&pch->file.xq);
1521                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1522                                 /* put the packet back and try again later */
1523                                 skb_queue_head(&pch->file.xq, skb);
1524                                 break;
1525                         }
1526                 }
1527         } else {
1528                 /* channel got deregistered */
1529                 skb_queue_purge(&pch->file.xq);
1530         }
1531         spin_unlock_bh(&pch->downl);
1532         /* see if there is anything from the attached unit to be sent */
1533         if (skb_queue_empty(&pch->file.xq)) {
1534                 read_lock_bh(&pch->upl);
1535                 ppp = pch->ppp;
1536                 if (ppp)
1537                         ppp_xmit_process(ppp);
1538                 read_unlock_bh(&pch->upl);
1539         }
1540 }
1541
1542 /*
1543  * Receive-side routines.
1544  */
1545
1546 /* misuse a few fields of the skb for MP reconstruction */
1547 #define sequence        priority
1548 #define BEbits          cb[0]
1549
1550 static inline void
1551 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1552 {
1553         ppp_recv_lock(ppp);
1554         if (!ppp->closing)
1555                 ppp_receive_frame(ppp, skb, pch);
1556         else
1557                 kfree_skb(skb);
1558         ppp_recv_unlock(ppp);
1559 }
1560
1561 void
1562 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1563 {
1564         struct channel *pch = chan->ppp;
1565         int proto;
1566
1567         if (!pch) {
1568                 kfree_skb(skb);
1569                 return;
1570         }
1571
1572         read_lock_bh(&pch->upl);
1573         if (!pskb_may_pull(skb, 2)) {
1574                 kfree_skb(skb);
1575                 if (pch->ppp) {
1576                         ++pch->ppp->dev->stats.rx_length_errors;
1577                         ppp_receive_error(pch->ppp);
1578                 }
1579                 goto done;
1580         }
1581
1582         proto = PPP_PROTO(skb);
1583         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1584                 /* put it on the channel queue */
1585                 skb_queue_tail(&pch->file.rq, skb);
1586                 /* drop old frames if queue too long */
1587                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1588                        (skb = skb_dequeue(&pch->file.rq)))
1589                         kfree_skb(skb);
1590                 wake_up_interruptible(&pch->file.rwait);
1591         } else {
1592                 ppp_do_recv(pch->ppp, skb, pch);
1593         }
1594
1595 done:
1596         read_unlock_bh(&pch->upl);
1597 }
1598
1599 /* Put a 0-length skb in the receive queue as an error indication */
1600 void
1601 ppp_input_error(struct ppp_channel *chan, int code)
1602 {
1603         struct channel *pch = chan->ppp;
1604         struct sk_buff *skb;
1605
1606         if (!pch)
1607                 return;
1608
1609         read_lock_bh(&pch->upl);
1610         if (pch->ppp) {
1611                 skb = alloc_skb(0, GFP_ATOMIC);
1612                 if (skb) {
1613                         skb->len = 0;           /* probably unnecessary */
1614                         skb->cb[0] = code;
1615                         ppp_do_recv(pch->ppp, skb, pch);
1616                 }
1617         }
1618         read_unlock_bh(&pch->upl);
1619 }
1620
1621 /*
1622  * We come in here to process a received frame.
1623  * The receive side of the ppp unit is locked.
1624  */
1625 static void
1626 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1627 {
1628         /* note: a 0-length skb is used as an error indication */
1629         if (skb->len > 0) {
1630 #ifdef CONFIG_PPP_MULTILINK
1631                 /* XXX do channel-level decompression here */
1632                 if (PPP_PROTO(skb) == PPP_MP)
1633                         ppp_receive_mp_frame(ppp, skb, pch);
1634                 else
1635 #endif /* CONFIG_PPP_MULTILINK */
1636                         ppp_receive_nonmp_frame(ppp, skb);
1637         } else {
1638                 kfree_skb(skb);
1639                 ppp_receive_error(ppp);
1640         }
1641 }
1642
1643 static void
1644 ppp_receive_error(struct ppp *ppp)
1645 {
1646         ++ppp->dev->stats.rx_errors;
1647         if (ppp->vj)
1648                 slhc_toss(ppp->vj);
1649 }
1650
1651 static void
1652 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1653 {
1654         struct sk_buff *ns;
1655         int proto, len, npi;
1656
1657         /*
1658          * Decompress the frame, if compressed.
1659          * Note that some decompressors need to see uncompressed frames
1660          * that come in as well as compressed frames.
1661          */
1662         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1663             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1664                 skb = ppp_decompress_frame(ppp, skb);
1665
1666         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1667                 goto err;
1668
1669         proto = PPP_PROTO(skb);
1670         switch (proto) {
1671         case PPP_VJC_COMP:
1672                 /* decompress VJ compressed packets */
1673                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1674                         goto err;
1675
1676                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1677                         /* copy to a new sk_buff with more tailroom */
1678                         ns = dev_alloc_skb(skb->len + 128);
1679                         if (!ns) {
1680                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1681                                 goto err;
1682                         }
1683                         skb_reserve(ns, 2);
1684                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1685                         kfree_skb(skb);
1686                         skb = ns;
1687                 }
1688                 else
1689                         skb->ip_summed = CHECKSUM_NONE;
1690
1691                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1692                 if (len <= 0) {
1693                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1694                         goto err;
1695                 }
1696                 len += 2;
1697                 if (len > skb->len)
1698                         skb_put(skb, len - skb->len);
1699                 else if (len < skb->len)
1700                         skb_trim(skb, len);
1701                 proto = PPP_IP;
1702                 break;
1703
1704         case PPP_VJC_UNCOMP:
1705                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1706                         goto err;
1707
1708                 /* Until we fix the decompressor need to make sure
1709                  * data portion is linear.
1710                  */
1711                 if (!pskb_may_pull(skb, skb->len))
1712                         goto err;
1713
1714                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1715                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1716                         goto err;
1717                 }
1718                 proto = PPP_IP;
1719                 break;
1720
1721         case PPP_CCP:
1722                 ppp_ccp_peek(ppp, skb, 1);
1723                 break;
1724         }
1725
1726         ++ppp->dev->stats.rx_packets;
1727         ppp->dev->stats.rx_bytes += skb->len - 2;
1728
1729         npi = proto_to_npindex(proto);
1730         if (npi < 0) {
1731                 /* control or unknown frame - pass it to pppd */
1732                 skb_queue_tail(&ppp->file.rq, skb);
1733                 /* limit queue length by dropping old frames */
1734                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1735                        (skb = skb_dequeue(&ppp->file.rq)))
1736                         kfree_skb(skb);
1737                 /* wake up any process polling or blocking on read */
1738                 wake_up_interruptible(&ppp->file.rwait);
1739
1740         } else {
1741                 /* network protocol frame - give it to the kernel */
1742
1743 #ifdef CONFIG_PPP_FILTER
1744                 /* check if the packet passes the pass and active filters */
1745                 /* the filter instructions are constructed assuming
1746                    a four-byte PPP header on each packet */
1747                 if (ppp->pass_filter || ppp->active_filter) {
1748                         if (skb_cloned(skb) &&
1749                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1750                                 goto err;
1751
1752                         *skb_push(skb, 2) = 0;
1753                         if (ppp->pass_filter &&
1754                             sk_run_filter(skb, ppp->pass_filter,
1755                                           ppp->pass_len) == 0) {
1756                                 if (ppp->debug & 1)
1757                                         printk(KERN_DEBUG "PPP: inbound frame "
1758                                                "not passed\n");
1759                                 kfree_skb(skb);
1760                                 return;
1761                         }
1762                         if (!(ppp->active_filter &&
1763                               sk_run_filter(skb, ppp->active_filter,
1764                                             ppp->active_len) == 0))
1765                                 ppp->last_recv = jiffies;
1766                         __skb_pull(skb, 2);
1767                 } else
1768 #endif /* CONFIG_PPP_FILTER */
1769                         ppp->last_recv = jiffies;
1770
1771                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1772                     ppp->npmode[npi] != NPMODE_PASS) {
1773                         kfree_skb(skb);
1774                 } else {
1775                         /* chop off protocol */
1776                         skb_pull_rcsum(skb, 2);
1777                         skb->dev = ppp->dev;
1778                         skb->protocol = htons(npindex_to_ethertype[npi]);
1779                         skb_reset_mac_header(skb);
1780                         netif_rx(skb);
1781                 }
1782         }
1783         return;
1784
1785  err:
1786         kfree_skb(skb);
1787         ppp_receive_error(ppp);
1788 }
1789
1790 static struct sk_buff *
1791 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1792 {
1793         int proto = PPP_PROTO(skb);
1794         struct sk_buff *ns;
1795         int len;
1796
1797         /* Until we fix all the decompressor's need to make sure
1798          * data portion is linear.
1799          */
1800         if (!pskb_may_pull(skb, skb->len))
1801                 goto err;
1802
1803         if (proto == PPP_COMP) {
1804                 int obuff_size;
1805
1806                 switch(ppp->rcomp->compress_proto) {
1807                 case CI_MPPE:
1808                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1809                         break;
1810                 default:
1811                         obuff_size = ppp->mru + PPP_HDRLEN;
1812                         break;
1813                 }
1814
1815                 ns = dev_alloc_skb(obuff_size);
1816                 if (!ns) {
1817                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1818                         goto err;
1819                 }
1820                 /* the decompressor still expects the A/C bytes in the hdr */
1821                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1822                                 skb->len + 2, ns->data, obuff_size);
1823                 if (len < 0) {
1824                         /* Pass the compressed frame to pppd as an
1825                            error indication. */
1826                         if (len == DECOMP_FATALERROR)
1827                                 ppp->rstate |= SC_DC_FERROR;
1828                         kfree_skb(ns);
1829                         goto err;
1830                 }
1831
1832                 kfree_skb(skb);
1833                 skb = ns;
1834                 skb_put(skb, len);
1835                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1836
1837         } else {
1838                 /* Uncompressed frame - pass to decompressor so it
1839                    can update its dictionary if necessary. */
1840                 if (ppp->rcomp->incomp)
1841                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1842                                            skb->len + 2);
1843         }
1844
1845         return skb;
1846
1847  err:
1848         ppp->rstate |= SC_DC_ERROR;
1849         ppp_receive_error(ppp);
1850         return skb;
1851 }
1852
1853 #ifdef CONFIG_PPP_MULTILINK
1854 /*
1855  * Receive a multilink frame.
1856  * We put it on the reconstruction queue and then pull off
1857  * as many completed frames as we can.
1858  */
1859 static void
1860 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1861 {
1862         u32 mask, seq;
1863         struct channel *ch;
1864         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1865
1866         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1867                 goto err;               /* no good, throw it away */
1868
1869         /* Decode sequence number and begin/end bits */
1870         if (ppp->flags & SC_MP_SHORTSEQ) {
1871                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1872                 mask = 0xfff;
1873         } else {
1874                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1875                 mask = 0xffffff;
1876         }
1877         skb->BEbits = skb->data[2];
1878         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1879
1880         /*
1881          * Do protocol ID decompression on the first fragment of each packet.
1882          */
1883         if ((skb->BEbits & B) && (skb->data[0] & 1))
1884                 *skb_push(skb, 1) = 0;
1885
1886         /*
1887          * Expand sequence number to 32 bits, making it as close
1888          * as possible to ppp->minseq.
1889          */
1890         seq |= ppp->minseq & ~mask;
1891         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1892                 seq += mask + 1;
1893         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1894                 seq -= mask + 1;        /* should never happen */
1895         skb->sequence = seq;
1896         pch->lastseq = seq;
1897
1898         /*
1899          * If this packet comes before the next one we were expecting,
1900          * drop it.
1901          */
1902         if (seq_before(seq, ppp->nextseq)) {
1903                 kfree_skb(skb);
1904                 ++ppp->dev->stats.rx_dropped;
1905                 ppp_receive_error(ppp);
1906                 return;
1907         }
1908
1909         /*
1910          * Reevaluate minseq, the minimum over all channels of the
1911          * last sequence number received on each channel.  Because of
1912          * the increasing sequence number rule, we know that any fragment
1913          * before `minseq' which hasn't arrived is never going to arrive.
1914          * The list of channels can't change because we have the receive
1915          * side of the ppp unit locked.
1916          */
1917         list_for_each_entry(ch, &ppp->channels, clist) {
1918                 if (seq_before(ch->lastseq, seq))
1919                         seq = ch->lastseq;
1920         }
1921         if (seq_before(ppp->minseq, seq))
1922                 ppp->minseq = seq;
1923
1924         /* Put the fragment on the reconstruction queue */
1925         ppp_mp_insert(ppp, skb);
1926
1927         /* If the queue is getting long, don't wait any longer for packets
1928            before the start of the queue. */
1929         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1930                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
1931                 if (seq_before(ppp->minseq, mskb->sequence))
1932                         ppp->minseq = mskb->sequence;
1933         }
1934
1935         /* Pull completed packets off the queue and receive them. */
1936         while ((skb = ppp_mp_reconstruct(ppp))) {
1937                 if (pskb_may_pull(skb, 2))
1938                         ppp_receive_nonmp_frame(ppp, skb);
1939                 else {
1940                         ++ppp->dev->stats.rx_length_errors;
1941                         kfree_skb(skb);
1942                         ppp_receive_error(ppp);
1943                 }
1944         }
1945
1946         return;
1947
1948  err:
1949         kfree_skb(skb);
1950         ppp_receive_error(ppp);
1951 }
1952
1953 /*
1954  * Insert a fragment on the MP reconstruction queue.
1955  * The queue is ordered by increasing sequence number.
1956  */
1957 static void
1958 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1959 {
1960         struct sk_buff *p;
1961         struct sk_buff_head *list = &ppp->mrq;
1962         u32 seq = skb->sequence;
1963
1964         /* N.B. we don't need to lock the list lock because we have the
1965            ppp unit receive-side lock. */
1966         skb_queue_walk(list, p) {
1967                 if (seq_before(seq, p->sequence))
1968                         break;
1969         }
1970         __skb_queue_before(list, p, skb);
1971 }
1972
1973 /*
1974  * Reconstruct a packet from the MP fragment queue.
1975  * We go through increasing sequence numbers until we find a
1976  * complete packet, or we get to the sequence number for a fragment
1977  * which hasn't arrived but might still do so.
1978  */
1979 static struct sk_buff *
1980 ppp_mp_reconstruct(struct ppp *ppp)
1981 {
1982         u32 seq = ppp->nextseq;
1983         u32 minseq = ppp->minseq;
1984         struct sk_buff_head *list = &ppp->mrq;
1985         struct sk_buff *p, *next;
1986         struct sk_buff *head, *tail;
1987         struct sk_buff *skb = NULL;
1988         int lost = 0, len = 0;
1989
1990         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1991                 return NULL;
1992         head = list->next;
1993         tail = NULL;
1994         for (p = head; p != (struct sk_buff *) list; p = next) {
1995                 next = p->next;
1996                 if (seq_before(p->sequence, seq)) {
1997                         /* this can't happen, anyway ignore the skb */
1998                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1999                                p->sequence, seq);
2000                         head = next;
2001                         continue;
2002                 }
2003                 if (p->sequence != seq) {
2004                         /* Fragment `seq' is missing.  If it is after
2005                            minseq, it might arrive later, so stop here. */
2006                         if (seq_after(seq, minseq))
2007                                 break;
2008                         /* Fragment `seq' is lost, keep going. */
2009                         lost = 1;
2010                         seq = seq_before(minseq, p->sequence)?
2011                                 minseq + 1: p->sequence;
2012                         next = p;
2013                         continue;
2014                 }
2015
2016                 /*
2017                  * At this point we know that all the fragments from
2018                  * ppp->nextseq to seq are either present or lost.
2019                  * Also, there are no complete packets in the queue
2020                  * that have no missing fragments and end before this
2021                  * fragment.
2022                  */
2023
2024                 /* B bit set indicates this fragment starts a packet */
2025                 if (p->BEbits & B) {
2026                         head = p;
2027                         lost = 0;
2028                         len = 0;
2029                 }
2030
2031                 len += p->len;
2032
2033                 /* Got a complete packet yet? */
2034                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
2035                         if (len > ppp->mrru + 2) {
2036                                 ++ppp->dev->stats.rx_length_errors;
2037                                 printk(KERN_DEBUG "PPP: reconstructed packet"
2038                                        " is too long (%d)\n", len);
2039                         } else if (p == head) {
2040                                 /* fragment is complete packet - reuse skb */
2041                                 tail = p;
2042                                 skb = skb_get(p);
2043                                 break;
2044                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
2045                                 ++ppp->dev->stats.rx_missed_errors;
2046                                 printk(KERN_DEBUG "PPP: no memory for "
2047                                        "reconstructed packet");
2048                         } else {
2049                                 tail = p;
2050                                 break;
2051                         }
2052                         ppp->nextseq = seq + 1;
2053                 }
2054
2055                 /*
2056                  * If this is the ending fragment of a packet,
2057                  * and we haven't found a complete valid packet yet,
2058                  * we can discard up to and including this fragment.
2059                  */
2060                 if (p->BEbits & E)
2061                         head = next;
2062
2063                 ++seq;
2064         }
2065
2066         /* If we have a complete packet, copy it all into one skb. */
2067         if (tail != NULL) {
2068                 /* If we have discarded any fragments,
2069                    signal a receive error. */
2070                 if (head->sequence != ppp->nextseq) {
2071                         if (ppp->debug & 1)
2072                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
2073                                        ppp->nextseq, head->sequence-1);
2074                         ++ppp->dev->stats.rx_dropped;
2075                         ppp_receive_error(ppp);
2076                 }
2077
2078                 if (head != tail)
2079                         /* copy to a single skb */
2080                         for (p = head; p != tail->next; p = p->next)
2081                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
2082                 ppp->nextseq = tail->sequence + 1;
2083                 head = tail->next;
2084         }
2085
2086         /* Discard all the skbuffs that we have copied the data out of
2087            or that we can't use. */
2088         while ((p = list->next) != head) {
2089                 __skb_unlink(p, list);
2090                 kfree_skb(p);
2091         }
2092
2093         return skb;
2094 }
2095 #endif /* CONFIG_PPP_MULTILINK */
2096
2097 /*
2098  * Channel interface.
2099  */
2100
2101 /* Create a new, unattached ppp channel. */
2102 int ppp_register_channel(struct ppp_channel *chan)
2103 {
2104         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2105 }
2106
2107 /* Create a new, unattached ppp channel for specified net. */
2108 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2109 {
2110         struct channel *pch;
2111         struct ppp_net *pn;
2112
2113         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2114         if (!pch)
2115                 return -ENOMEM;
2116
2117         pn = ppp_pernet(net);
2118
2119         pch->ppp = NULL;
2120         pch->chan = chan;
2121         pch->chan_net = net;
2122         chan->ppp = pch;
2123         init_ppp_file(&pch->file, CHANNEL);
2124         pch->file.hdrlen = chan->hdrlen;
2125 #ifdef CONFIG_PPP_MULTILINK
2126         pch->lastseq = -1;
2127 #endif /* CONFIG_PPP_MULTILINK */
2128         init_rwsem(&pch->chan_sem);
2129         spin_lock_init(&pch->downl);
2130         rwlock_init(&pch->upl);
2131
2132         spin_lock_bh(&pn->all_channels_lock);
2133         pch->file.index = ++pn->last_channel_index;
2134         list_add(&pch->list, &pn->new_channels);
2135         atomic_inc(&channel_count);
2136         spin_unlock_bh(&pn->all_channels_lock);
2137
2138         return 0;
2139 }
2140
2141 /*
2142  * Return the index of a channel.
2143  */
2144 int ppp_channel_index(struct ppp_channel *chan)
2145 {
2146         struct channel *pch = chan->ppp;
2147
2148         if (pch)
2149                 return pch->file.index;
2150         return -1;
2151 }
2152
2153 /*
2154  * Return the PPP unit number to which a channel is connected.
2155  */
2156 int ppp_unit_number(struct ppp_channel *chan)
2157 {
2158         struct channel *pch = chan->ppp;
2159         int unit = -1;
2160
2161         if (pch) {
2162                 read_lock_bh(&pch->upl);
2163                 if (pch->ppp)
2164                         unit = pch->ppp->file.index;
2165                 read_unlock_bh(&pch->upl);
2166         }
2167         return unit;
2168 }
2169
2170 /*
2171  * Return the PPP device interface name of a channel.
2172  */
2173 char *ppp_dev_name(struct ppp_channel *chan)
2174 {
2175         struct channel *pch = chan->ppp;
2176         char *name = NULL;
2177
2178         if (pch) {
2179                 read_lock_bh(&pch->upl);
2180                 if (pch->ppp && pch->ppp->dev)
2181                         name = pch->ppp->dev->name;
2182                 read_unlock_bh(&pch->upl);
2183         }
2184         return name;
2185 }
2186
2187
2188 /*
2189  * Disconnect a channel from the generic layer.
2190  * This must be called in process context.
2191  */
2192 void
2193 ppp_unregister_channel(struct ppp_channel *chan)
2194 {
2195         struct channel *pch = chan->ppp;
2196         struct ppp_net *pn;
2197
2198         if (!pch)
2199                 return;         /* should never happen */
2200
2201         chan->ppp = NULL;
2202
2203         /*
2204          * This ensures that we have returned from any calls into the
2205          * the channel's start_xmit or ioctl routine before we proceed.
2206          */
2207         down_write(&pch->chan_sem);
2208         spin_lock_bh(&pch->downl);
2209         pch->chan = NULL;
2210         spin_unlock_bh(&pch->downl);
2211         up_write(&pch->chan_sem);
2212         ppp_disconnect_channel(pch);
2213
2214         pn = ppp_pernet(pch->chan_net);
2215         spin_lock_bh(&pn->all_channels_lock);
2216         list_del(&pch->list);
2217         spin_unlock_bh(&pn->all_channels_lock);
2218
2219         pch->file.dead = 1;
2220         wake_up_interruptible(&pch->file.rwait);
2221         if (atomic_dec_and_test(&pch->file.refcnt))
2222                 ppp_destroy_channel(pch);
2223 }
2224
2225 /*
2226  * Callback from a channel when it can accept more to transmit.
2227  * This should be called at BH/softirq level, not interrupt level.
2228  */
2229 void
2230 ppp_output_wakeup(struct ppp_channel *chan)
2231 {
2232         struct channel *pch = chan->ppp;
2233
2234         if (!pch)
2235                 return;
2236         ppp_channel_push(pch);
2237 }
2238
2239 /*
2240  * Compression control.
2241  */
2242
2243 /* Process the PPPIOCSCOMPRESS ioctl. */
2244 static int
2245 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2246 {
2247         int err;
2248         struct compressor *cp, *ocomp;
2249         struct ppp_option_data data;
2250         void *state, *ostate;
2251         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2252
2253         err = -EFAULT;
2254         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2255             (data.length <= CCP_MAX_OPTION_LENGTH &&
2256              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2257                 goto out;
2258         err = -EINVAL;
2259         if (data.length > CCP_MAX_OPTION_LENGTH ||
2260             ccp_option[1] < 2 || ccp_option[1] > data.length)
2261                 goto out;
2262
2263         cp = try_then_request_module(
2264                 find_compressor(ccp_option[0]),
2265                 "ppp-compress-%d", ccp_option[0]);
2266         if (!cp)
2267                 goto out;
2268
2269         err = -ENOBUFS;
2270         if (data.transmit) {
2271                 state = cp->comp_alloc(ccp_option, data.length);
2272                 if (state) {
2273                         ppp_xmit_lock(ppp);
2274                         ppp->xstate &= ~SC_COMP_RUN;
2275                         ocomp = ppp->xcomp;
2276                         ostate = ppp->xc_state;
2277                         ppp->xcomp = cp;
2278                         ppp->xc_state = state;
2279                         ppp_xmit_unlock(ppp);
2280                         if (ostate) {
2281                                 ocomp->comp_free(ostate);
2282                                 module_put(ocomp->owner);
2283                         }
2284                         err = 0;
2285                 } else
2286                         module_put(cp->owner);
2287
2288         } else {
2289                 state = cp->decomp_alloc(ccp_option, data.length);
2290                 if (state) {
2291                         ppp_recv_lock(ppp);
2292                         ppp->rstate &= ~SC_DECOMP_RUN;
2293                         ocomp = ppp->rcomp;
2294                         ostate = ppp->rc_state;
2295                         ppp->rcomp = cp;
2296                         ppp->rc_state = state;
2297                         ppp_recv_unlock(ppp);
2298                         if (ostate) {
2299                                 ocomp->decomp_free(ostate);
2300                                 module_put(ocomp->owner);
2301                         }
2302                         err = 0;
2303                 } else
2304                         module_put(cp->owner);
2305         }
2306
2307  out:
2308         return err;
2309 }
2310
2311 /*
2312  * Look at a CCP packet and update our state accordingly.
2313  * We assume the caller has the xmit or recv path locked.
2314  */
2315 static void
2316 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2317 {
2318         unsigned char *dp;
2319         int len;
2320
2321         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2322                 return; /* no header */
2323         dp = skb->data + 2;
2324
2325         switch (CCP_CODE(dp)) {
2326         case CCP_CONFREQ:
2327
2328                 /* A ConfReq starts negotiation of compression
2329                  * in one direction of transmission,
2330                  * and hence brings it down...but which way?
2331                  *
2332                  * Remember:
2333                  * A ConfReq indicates what the sender would like to receive
2334                  */
2335                 if(inbound)
2336                         /* He is proposing what I should send */
2337                         ppp->xstate &= ~SC_COMP_RUN;
2338                 else
2339                         /* I am proposing to what he should send */
2340                         ppp->rstate &= ~SC_DECOMP_RUN;
2341
2342                 break;
2343
2344         case CCP_TERMREQ:
2345         case CCP_TERMACK:
2346                 /*
2347                  * CCP is going down, both directions of transmission
2348                  */
2349                 ppp->rstate &= ~SC_DECOMP_RUN;
2350                 ppp->xstate &= ~SC_COMP_RUN;
2351                 break;
2352
2353         case CCP_CONFACK:
2354                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2355                         break;
2356                 len = CCP_LENGTH(dp);
2357                 if (!pskb_may_pull(skb, len + 2))
2358                         return;         /* too short */
2359                 dp += CCP_HDRLEN;
2360                 len -= CCP_HDRLEN;
2361                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2362                         break;
2363                 if (inbound) {
2364                         /* we will start receiving compressed packets */
2365                         if (!ppp->rc_state)
2366                                 break;
2367                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2368                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2369                                 ppp->rstate |= SC_DECOMP_RUN;
2370                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2371                         }
2372                 } else {
2373                         /* we will soon start sending compressed packets */
2374                         if (!ppp->xc_state)
2375                                 break;
2376                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2377                                         ppp->file.index, 0, ppp->debug))
2378                                 ppp->xstate |= SC_COMP_RUN;
2379                 }
2380                 break;
2381
2382         case CCP_RESETACK:
2383                 /* reset the [de]compressor */
2384                 if ((ppp->flags & SC_CCP_UP) == 0)
2385                         break;
2386                 if (inbound) {
2387                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2388                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2389                                 ppp->rstate &= ~SC_DC_ERROR;
2390                         }
2391                 } else {
2392                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2393                                 ppp->xcomp->comp_reset(ppp->xc_state);
2394                 }
2395                 break;
2396         }
2397 }
2398
2399 /* Free up compression resources. */
2400 static void
2401 ppp_ccp_closed(struct ppp *ppp)
2402 {
2403         void *xstate, *rstate;
2404         struct compressor *xcomp, *rcomp;
2405
2406         ppp_lock(ppp);
2407         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2408         ppp->xstate = 0;
2409         xcomp = ppp->xcomp;
2410         xstate = ppp->xc_state;
2411         ppp->xc_state = NULL;
2412         ppp->rstate = 0;
2413         rcomp = ppp->rcomp;
2414         rstate = ppp->rc_state;
2415         ppp->rc_state = NULL;
2416         ppp_unlock(ppp);
2417
2418         if (xstate) {
2419                 xcomp->comp_free(xstate);
2420                 module_put(xcomp->owner);
2421         }
2422         if (rstate) {
2423                 rcomp->decomp_free(rstate);
2424                 module_put(rcomp->owner);
2425         }
2426 }
2427
2428 /* List of compressors. */
2429 static LIST_HEAD(compressor_list);
2430 static DEFINE_SPINLOCK(compressor_list_lock);
2431
2432 struct compressor_entry {
2433         struct list_head list;
2434         struct compressor *comp;
2435 };
2436
2437 static struct compressor_entry *
2438 find_comp_entry(int proto)
2439 {
2440         struct compressor_entry *ce;
2441
2442         list_for_each_entry(ce, &compressor_list, list) {
2443                 if (ce->comp->compress_proto == proto)
2444                         return ce;
2445         }
2446         return NULL;
2447 }
2448
2449 /* Register a compressor */
2450 int
2451 ppp_register_compressor(struct compressor *cp)
2452 {
2453         struct compressor_entry *ce;
2454         int ret;
2455         spin_lock(&compressor_list_lock);
2456         ret = -EEXIST;
2457         if (find_comp_entry(cp->compress_proto))
2458                 goto out;
2459         ret = -ENOMEM;
2460         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2461         if (!ce)
2462                 goto out;
2463         ret = 0;
2464         ce->comp = cp;
2465         list_add(&ce->list, &compressor_list);
2466  out:
2467         spin_unlock(&compressor_list_lock);
2468         return ret;
2469 }
2470
2471 /* Unregister a compressor */
2472 void
2473 ppp_unregister_compressor(struct compressor *cp)
2474 {
2475         struct compressor_entry *ce;
2476
2477         spin_lock(&compressor_list_lock);
2478         ce = find_comp_entry(cp->compress_proto);
2479         if (ce && ce->comp == cp) {
2480                 list_del(&ce->list);
2481                 kfree(ce);
2482         }
2483         spin_unlock(&compressor_list_lock);
2484 }
2485
2486 /* Find a compressor. */
2487 static struct compressor *
2488 find_compressor(int type)
2489 {
2490         struct compressor_entry *ce;
2491         struct compressor *cp = NULL;
2492
2493         spin_lock(&compressor_list_lock);
2494         ce = find_comp_entry(type);
2495         if (ce) {
2496                 cp = ce->comp;
2497                 if (!try_module_get(cp->owner))
2498                         cp = NULL;
2499         }
2500         spin_unlock(&compressor_list_lock);
2501         return cp;
2502 }
2503
2504 /*
2505  * Miscelleneous stuff.
2506  */
2507
2508 static void
2509 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2510 {
2511         struct slcompress *vj = ppp->vj;
2512
2513         memset(st, 0, sizeof(*st));
2514         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2515         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2516         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2517         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2518         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2519         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2520         if (!vj)
2521                 return;
2522         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2523         st->vj.vjs_compressed = vj->sls_o_compressed;
2524         st->vj.vjs_searches = vj->sls_o_searches;
2525         st->vj.vjs_misses = vj->sls_o_misses;
2526         st->vj.vjs_errorin = vj->sls_i_error;
2527         st->vj.vjs_tossed = vj->sls_i_tossed;
2528         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2529         st->vj.vjs_compressedin = vj->sls_i_compressed;
2530 }
2531
2532 /*
2533  * Stuff for handling the lists of ppp units and channels
2534  * and for initialization.
2535  */
2536
2537 /*
2538  * Create a new ppp interface unit.  Fails if it can't allocate memory
2539  * or if there is already a unit with the requested number.
2540  * unit == -1 means allocate a new number.
2541  */
2542 static struct ppp *
2543 ppp_create_interface(struct net *net, int unit, int *retp)
2544 {
2545         struct ppp *ppp;
2546         struct ppp_net *pn;
2547         struct net_device *dev = NULL;
2548         int ret = -ENOMEM;
2549         int i;
2550
2551         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2552         if (!dev)
2553                 goto out1;
2554
2555         pn = ppp_pernet(net);
2556
2557         ppp = netdev_priv(dev);
2558         ppp->dev = dev;
2559         ppp->mru = PPP_MRU;
2560         init_ppp_file(&ppp->file, INTERFACE);
2561         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2562         for (i = 0; i < NUM_NP; ++i)
2563                 ppp->npmode[i] = NPMODE_PASS;
2564         INIT_LIST_HEAD(&ppp->channels);
2565         spin_lock_init(&ppp->rlock);
2566         spin_lock_init(&ppp->wlock);
2567 #ifdef CONFIG_PPP_MULTILINK
2568         ppp->minseq = -1;
2569         skb_queue_head_init(&ppp->mrq);
2570 #endif /* CONFIG_PPP_MULTILINK */
2571
2572         /*
2573          * drum roll: don't forget to set
2574          * the net device is belong to
2575          */
2576         dev_net_set(dev, net);
2577
2578         ret = -EEXIST;
2579         mutex_lock(&pn->all_ppp_mutex);
2580
2581         if (unit < 0) {
2582                 unit = unit_get(&pn->units_idr, ppp);
2583                 if (unit < 0) {
2584                         *retp = unit;
2585                         goto out2;
2586                 }
2587         } else {
2588                 if (unit_find(&pn->units_idr, unit))
2589                         goto out2; /* unit already exists */
2590                 /*
2591                  * if caller need a specified unit number
2592                  * lets try to satisfy him, otherwise --
2593                  * he should better ask us for new unit number
2594                  *
2595                  * NOTE: yes I know that returning EEXIST it's not
2596                  * fair but at least pppd will ask us to allocate
2597                  * new unit in this case so user is happy :)
2598                  */
2599                 unit = unit_set(&pn->units_idr, ppp, unit);
2600                 if (unit < 0)
2601                         goto out2;
2602         }
2603
2604         /* Initialize the new ppp unit */
2605         ppp->file.index = unit;
2606         sprintf(dev->name, "ppp%d", unit);
2607
2608         ret = register_netdev(dev);
2609         if (ret != 0) {
2610                 unit_put(&pn->units_idr, unit);
2611                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2612                        dev->name, ret);
2613                 goto out2;
2614         }
2615
2616         ppp->ppp_net = net;
2617
2618         atomic_inc(&ppp_unit_count);
2619         mutex_unlock(&pn->all_ppp_mutex);
2620
2621         *retp = 0;
2622         return ppp;
2623
2624 out2:
2625         mutex_unlock(&pn->all_ppp_mutex);
2626         free_netdev(dev);
2627 out1:
2628         *retp = ret;
2629         return NULL;
2630 }
2631
2632 /*
2633  * Initialize a ppp_file structure.
2634  */
2635 static void
2636 init_ppp_file(struct ppp_file *pf, int kind)
2637 {
2638         pf->kind = kind;
2639         skb_queue_head_init(&pf->xq);
2640         skb_queue_head_init(&pf->rq);
2641         atomic_set(&pf->refcnt, 1);
2642         init_waitqueue_head(&pf->rwait);
2643 }
2644
2645 /*
2646  * Take down a ppp interface unit - called when the owning file
2647  * (the one that created the unit) is closed or detached.
2648  */
2649 static void ppp_shutdown_interface(struct ppp *ppp)
2650 {
2651         struct ppp_net *pn;
2652
2653         pn = ppp_pernet(ppp->ppp_net);
2654         mutex_lock(&pn->all_ppp_mutex);
2655
2656         /* This will call dev_close() for us. */
2657         ppp_lock(ppp);
2658         if (!ppp->closing) {
2659                 ppp->closing = 1;
2660                 ppp_unlock(ppp);
2661                 unregister_netdev(ppp->dev);
2662         } else
2663                 ppp_unlock(ppp);
2664
2665         unit_put(&pn->units_idr, ppp->file.index);
2666         ppp->file.dead = 1;
2667         ppp->owner = NULL;
2668         wake_up_interruptible(&ppp->file.rwait);
2669
2670         mutex_unlock(&pn->all_ppp_mutex);
2671 }
2672
2673 /*
2674  * Free the memory used by a ppp unit.  This is only called once
2675  * there are no channels connected to the unit and no file structs
2676  * that reference the unit.
2677  */
2678 static void ppp_destroy_interface(struct ppp *ppp)
2679 {
2680         atomic_dec(&ppp_unit_count);
2681
2682         if (!ppp->file.dead || ppp->n_channels) {
2683                 /* "can't happen" */
2684                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2685                        "n_channels=%d !\n", ppp, ppp->file.dead,
2686                        ppp->n_channels);
2687                 return;
2688         }
2689
2690         ppp_ccp_closed(ppp);
2691         if (ppp->vj) {
2692                 slhc_free(ppp->vj);
2693                 ppp->vj = NULL;
2694         }
2695         skb_queue_purge(&ppp->file.xq);
2696         skb_queue_purge(&ppp->file.rq);
2697 #ifdef CONFIG_PPP_MULTILINK
2698         skb_queue_purge(&ppp->mrq);
2699 #endif /* CONFIG_PPP_MULTILINK */
2700 #ifdef CONFIG_PPP_FILTER
2701         kfree(ppp->pass_filter);
2702         ppp->pass_filter = NULL;
2703         kfree(ppp->active_filter);
2704         ppp->active_filter = NULL;
2705 #endif /* CONFIG_PPP_FILTER */
2706
2707         kfree_skb(ppp->xmit_pending);
2708
2709         free_netdev(ppp->dev);
2710 }
2711
2712 /*
2713  * Locate an existing ppp unit.
2714  * The caller should have locked the all_ppp_mutex.
2715  */
2716 static struct ppp *
2717 ppp_find_unit(struct ppp_net *pn, int unit)
2718 {
2719         return unit_find(&pn->units_idr, unit);
2720 }
2721
2722 /*
2723  * Locate an existing ppp channel.
2724  * The caller should have locked the all_channels_lock.
2725  * First we look in the new_channels list, then in the
2726  * all_channels list.  If found in the new_channels list,
2727  * we move it to the all_channels list.  This is for speed
2728  * when we have a lot of channels in use.
2729  */
2730 static struct channel *
2731 ppp_find_channel(struct ppp_net *pn, int unit)
2732 {
2733         struct channel *pch;
2734
2735         list_for_each_entry(pch, &pn->new_channels, list) {
2736                 if (pch->file.index == unit) {
2737                         list_move(&pch->list, &pn->all_channels);
2738                         return pch;
2739                 }
2740         }
2741
2742         list_for_each_entry(pch, &pn->all_channels, list) {
2743                 if (pch->file.index == unit)
2744                         return pch;
2745         }
2746
2747         return NULL;
2748 }
2749
2750 /*
2751  * Connect a PPP channel to a PPP interface unit.
2752  */
2753 static int
2754 ppp_connect_channel(struct channel *pch, int unit)
2755 {
2756         struct ppp *ppp;
2757         struct ppp_net *pn;
2758         int ret = -ENXIO;
2759         int hdrlen;
2760
2761         pn = ppp_pernet(pch->chan_net);
2762
2763         mutex_lock(&pn->all_ppp_mutex);
2764         ppp = ppp_find_unit(pn, unit);
2765         if (!ppp)
2766                 goto out;
2767         write_lock_bh(&pch->upl);
2768         ret = -EINVAL;
2769         if (pch->ppp)
2770                 goto outl;
2771
2772         ppp_lock(ppp);
2773         if (pch->file.hdrlen > ppp->file.hdrlen)
2774                 ppp->file.hdrlen = pch->file.hdrlen;
2775         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2776         if (hdrlen > ppp->dev->hard_header_len)
2777                 ppp->dev->hard_header_len = hdrlen;
2778         list_add_tail(&pch->clist, &ppp->channels);
2779         ++ppp->n_channels;
2780         pch->ppp = ppp;
2781         atomic_inc(&ppp->file.refcnt);
2782         ppp_unlock(ppp);
2783         ret = 0;
2784
2785  outl:
2786         write_unlock_bh(&pch->upl);
2787  out:
2788         mutex_unlock(&pn->all_ppp_mutex);
2789         return ret;
2790 }
2791
2792 /*
2793  * Disconnect a channel from its ppp unit.
2794  */
2795 static int
2796 ppp_disconnect_channel(struct channel *pch)
2797 {
2798         struct ppp *ppp;
2799         int err = -EINVAL;
2800
2801         write_lock_bh(&pch->upl);
2802         ppp = pch->ppp;
2803         pch->ppp = NULL;
2804         write_unlock_bh(&pch->upl);
2805         if (ppp) {
2806                 /* remove it from the ppp unit's list */
2807                 ppp_lock(ppp);
2808                 list_del(&pch->clist);
2809                 if (--ppp->n_channels == 0)
2810                         wake_up_interruptible(&ppp->file.rwait);
2811                 ppp_unlock(ppp);
2812                 if (atomic_dec_and_test(&ppp->file.refcnt))
2813                         ppp_destroy_interface(ppp);
2814                 err = 0;
2815         }
2816         return err;
2817 }
2818
2819 /*
2820  * Free up the resources used by a ppp channel.
2821  */
2822 static void ppp_destroy_channel(struct channel *pch)
2823 {
2824         atomic_dec(&channel_count);
2825
2826         if (!pch->file.dead) {
2827                 /* "can't happen" */
2828                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2829                        pch);
2830                 return;
2831         }
2832         skb_queue_purge(&pch->file.xq);
2833         skb_queue_purge(&pch->file.rq);
2834         kfree(pch);
2835 }
2836
2837 static void __exit ppp_cleanup(void)
2838 {
2839         /* should never happen */
2840         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2841                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2842         unregister_chrdev(PPP_MAJOR, "ppp");
2843         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2844         class_destroy(ppp_class);
2845         unregister_pernet_device(&ppp_net_ops);
2846 }
2847
2848 /*
2849  * Units handling. Caller must protect concurrent access
2850  * by holding all_ppp_mutex
2851  */
2852
2853 /* associate pointer with specified number */
2854 static int unit_set(struct idr *p, void *ptr, int n)
2855 {
2856         int unit, err;
2857
2858 again:
2859         if (!idr_pre_get(p, GFP_KERNEL)) {
2860                 printk(KERN_ERR "PPP: No free memory for idr\n");
2861                 return -ENOMEM;
2862         }
2863
2864         err = idr_get_new_above(p, ptr, n, &unit);
2865         if (err == -EAGAIN)
2866                 goto again;
2867
2868         if (unit != n) {
2869                 idr_remove(p, unit);
2870                 return -EINVAL;
2871         }
2872
2873         return unit;
2874 }
2875
2876 /* get new free unit number and associate pointer with it */
2877 static int unit_get(struct idr *p, void *ptr)
2878 {
2879         int unit, err;
2880
2881 again:
2882         if (!idr_pre_get(p, GFP_KERNEL)) {
2883                 printk(KERN_ERR "PPP: No free memory for idr\n");
2884                 return -ENOMEM;
2885         }
2886
2887         err = idr_get_new_above(p, ptr, 0, &unit);
2888         if (err == -EAGAIN)
2889                 goto again;
2890
2891         return unit;
2892 }
2893
2894 /* put unit number back to a pool */
2895 static void unit_put(struct idr *p, int n)
2896 {
2897         idr_remove(p, n);
2898 }
2899
2900 /* get pointer associated with the number */
2901 static void *unit_find(struct idr *p, int n)
2902 {
2903         return idr_find(p, n);
2904 }
2905
2906 /* Module/initialization stuff */
2907
2908 module_init(ppp_init);
2909 module_exit(ppp_cleanup);
2910
2911 EXPORT_SYMBOL(ppp_register_net_channel);
2912 EXPORT_SYMBOL(ppp_register_channel);
2913 EXPORT_SYMBOL(ppp_unregister_channel);
2914 EXPORT_SYMBOL(ppp_channel_index);
2915 EXPORT_SYMBOL(ppp_unit_number);
2916 EXPORT_SYMBOL(ppp_dev_name);
2917 EXPORT_SYMBOL(ppp_input);
2918 EXPORT_SYMBOL(ppp_input_error);
2919 EXPORT_SYMBOL(ppp_output_wakeup);
2920 EXPORT_SYMBOL(ppp_register_compressor);
2921 EXPORT_SYMBOL(ppp_unregister_compressor);
2922 MODULE_LICENSE("GPL");
2923 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
2924 MODULE_ALIAS("devname:ppp");