drivers/net/ppp_generic.c

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