git.oblomov.eu Git - linux-2.6/blob - drivers/net/ppp_generic.c

   1 /*
   2  * Generic PPP layer for Linux.
   3  *
   4  * Copyright 1999-2002 Paul Mackerras.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  *
  11  * The generic PPP layer handles the PPP network interfaces, the
  12  * /dev/ppp device, packet and VJ compression, and multilink.
  13  * It talks to PPP `channels' via the interface defined in
  14  * include/linux/ppp_channel.h.  Channels provide the basic means for
  15  * sending and receiving PPP frames on some kind of communications
  16  * channel.
  17  *
  18  * Part of the code in this driver was inspired by the old async-only
  19  * PPP driver, written by Michael Callahan and Al Longyear, and
  20  * subsequently hacked by Paul Mackerras.
  21  *
  22  * ==FILEVERSION 20041108==
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/kmod.h>
  28 #include <linux/init.h>
  29 #include <linux/list.h>
  30 #include <linux/idr.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/poll.h>
  33 #include <linux/ppp_defs.h>
  34 #include <linux/filter.h>
  35 #include <linux/if_ppp.h>
  36 #include <linux/ppp_channel.h>
  37 #include <linux/ppp-comp.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/rtnetlink.h>
  40 #include <linux/if_arp.h>
  41 #include <linux/ip.h>
  42 #include <linux/tcp.h>
  43 #include <linux/smp_lock.h>
  44 #include <linux/spinlock.h>
  45 #include <linux/rwsem.h>
  46 #include <linux/stddef.h>
  47 #include <linux/device.h>
  48 #include <linux/mutex.h>
  49 #include <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 #define MIN_FRAG_SIZE   64
  72
  73 /*
  74  * An instance of /dev/ppp can be associated with either a ppp
  75  * interface unit or a ppp channel.  In both cases, file->private_data
  76  * points to one of these.
  77  */
  78 struct ppp_file {
  79         enum {
  80                 INTERFACE=1, CHANNEL
  81         }               kind;
  82         struct sk_buff_head xq;         /* pppd transmit queue */
  83         struct sk_buff_head rq;         /* receive queue for pppd */
  84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  86         int             hdrlen;         /* space to leave for headers */
  87         int             index;          /* interface unit / channel number */
  88         int             dead;           /* unit/channel has been shut down */
  89 };
  90
  91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  92
  93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  95
  96 /*
  97  * Data structure describing one ppp unit.
  98  * A ppp unit corresponds to a ppp network interface device
  99  * and represents a multilink bundle.
 100  * It can have 0 or more ppp channels connected to it.
 101  */
 102 struct ppp {
 103         struct ppp_file file;           /* stuff for read/write/poll 0 */
 104         struct file     *owner;         /* file that owns this unit 48 */
 105         struct list_head channels;      /* list of attached channels 4c */
 106         int             n_channels;     /* how many channels are attached 54 */
 107         spinlock_t      rlock;          /* lock for receive side 58 */
 108         spinlock_t      wlock;          /* lock for transmit side 5c */
 109         int             mru;            /* max receive unit 60 */
 110         unsigned int    flags;          /* control bits 64 */
 111         unsigned int    xstate;         /* transmit state bits 68 */
 112         unsigned int    rstate;         /* receive state bits 6c */
 113         int             debug;          /* debug flags 70 */
 114         struct slcompress *vj;          /* state for VJ header compression */
 115         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 116         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 117         struct compressor *xcomp;       /* transmit packet compressor 8c */
 118         void            *xc_state;      /* its internal state 90 */
 119         struct compressor *rcomp;       /* receive decompressor 94 */
 120         void            *rc_state;      /* its internal state 98 */
 121         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 122         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 123         struct net_device *dev;         /* network interface device a4 */
 124         int             closing;        /* is device closing down? a8 */
 125 #ifdef CONFIG_PPP_MULTILINK
 126         int             nxchan;         /* next channel to send something on */
 127         u32             nxseq;          /* next sequence number to send */
 128         int             mrru;           /* MP: max reconst. receive unit */
 129         u32             nextseq;        /* MP: seq no of next packet */
 130         u32             minseq;         /* MP: min of most recent seqnos */
 131         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 132 #endif /* CONFIG_PPP_MULTILINK */
 133 #ifdef CONFIG_PPP_FILTER
 134         struct sock_filter *pass_filter;        /* filter for packets to pass */
 135         struct sock_filter *active_filter;/* filter for pkts to reset idle */
 136         unsigned pass_len, active_len;
 137 #endif /* CONFIG_PPP_FILTER */
 138         struct net      *ppp_net;       /* the net we belong to */
 139 };
 140
 141 /*
 142  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 143  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 144  * SC_MUST_COMP
 145  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 146  * Bits in xstate: SC_COMP_RUN
 147  */
 148 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 149                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 150                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 151
 152 /*
 153  * Private data structure for each channel.
 154  * This includes the data structure used for multilink.
 155  */
 156 struct channel {
 157         struct ppp_file file;           /* stuff for read/write/poll */
 158         struct list_head list;          /* link in all/new_channels list */
 159         struct ppp_channel *chan;       /* public channel data structure */
 160         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 161         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 162         struct ppp      *ppp;           /* ppp unit we're connected to */
 163         struct net      *chan_net;      /* the net channel belongs to */
 164         struct list_head clist;         /* link in list of channels per unit */
 165         rwlock_t        upl;            /* protects `ppp' */
 166 #ifdef CONFIG_PPP_MULTILINK
 167         u8              avail;          /* flag used in multilink stuff */
 168         u8              had_frag;       /* >= 1 fragments have been sent */
 169         u32             lastseq;        /* MP: last sequence # received */
 170 #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 atomic_t ppp_unit_count = ATOMIC_INIT(0);
 183 static atomic_t channel_count = ATOMIC_INIT(0);
 184
 185 /* per-net private data for this module */
 186 static int ppp_net_id;
 187 struct ppp_net {
 188         /* units to ppp mapping */
 189         struct idr units_idr;
 190
 191         /*
 192          * all_ppp_mutex protects the units_idr mapping.
 193          * It also ensures that finding a ppp unit in the units_idr
 194          * map and updating its file.refcnt field is atomic.
 195          */
 196         struct mutex all_ppp_mutex;
 197
 198         /* channels */
 199         struct list_head all_channels;
 200         struct list_head new_channels;
 201         int last_channel_index;
 202
 203         /*
 204          * all_channels_lock protects all_channels and
 205          * last_channel_index, and the atomicity of find
 206          * a channel and updating its file.refcnt field.
 207          */
 208         spinlock_t all_channels_lock;
 209 };
 210
 211 /* Get the PPP protocol number from a skb */
 212 #define PPP_PROTO(skb)  (((skb)->data[0] << 8) + (skb)->data[1])
 213
 214 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 215 #define PPP_MAX_RQLEN   32
 216
 217 /*
 218  * Maximum number of multilink fragments queued up.
 219  * This has to be large enough to cope with the maximum latency of
 220  * the slowest channel relative to the others.  Strictly it should
 221  * depend on the number of channels and their characteristics.
 222  */
 223 #define PPP_MP_MAX_QLEN 128
 224
 225 /* Multilink header bits. */
 226 #define B       0x80            /* this fragment begins a packet */
 227 #define E       0x40            /* this fragment ends a packet */
 228
 229 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 230 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 231 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 232
 233 /* Prototypes. */
 234 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 235                         struct file *file, unsigned int cmd, unsigned long arg);
 236 static void ppp_xmit_process(struct ppp *ppp);
 237 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 238 static void ppp_push(struct ppp *ppp);
 239 static void ppp_channel_push(struct channel *pch);
 240 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 241                               struct channel *pch);
 242 static void ppp_receive_error(struct ppp *ppp);
 243 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 244 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 245                                             struct sk_buff *skb);
 246 #ifdef CONFIG_PPP_MULTILINK
 247 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 248                                 struct channel *pch);
 249 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 250 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 251 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 252 #endif /* CONFIG_PPP_MULTILINK */
 253 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 254 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 255 static void ppp_ccp_closed(struct ppp *ppp);
 256 static struct compressor *find_compressor(int type);
 257 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 258 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 259 static void init_ppp_file(struct ppp_file *pf, int kind);
 260 static void ppp_shutdown_interface(struct ppp *ppp);
 261 static void ppp_destroy_interface(struct ppp *ppp);
 262 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 263 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 264 static int ppp_connect_channel(struct channel *pch, int unit);
 265 static int ppp_disconnect_channel(struct channel *pch);
 266 static void ppp_destroy_channel(struct channel *pch);
 267 static int unit_get(struct idr *p, void *ptr);
 268 static int unit_set(struct idr *p, void *ptr, int n);
 269 static void unit_put(struct idr *p, int n);
 270 static void *unit_find(struct idr *p, int n);
 271
 272 static struct class *ppp_class;
 273
 274 /* per net-namespace data */
 275 static inline struct ppp_net *ppp_pernet(struct net *net)
 276 {
 277         BUG_ON(!net);
 278
 279         return net_generic(net, ppp_net_id);
 280 }
 281
 282 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 283 static inline int proto_to_npindex(int proto)
 284 {
 285         switch (proto) {
 286         case PPP_IP:
 287                 return NP_IP;
 288         case PPP_IPV6:
 289                 return NP_IPV6;
 290         case PPP_IPX:
 291                 return NP_IPX;
 292         case PPP_AT:
 293                 return NP_AT;
 294         case PPP_MPLS_UC:
 295                 return NP_MPLS_UC;
 296         case PPP_MPLS_MC:
 297                 return NP_MPLS_MC;
 298         }
 299         return -EINVAL;
 300 }
 301
 302 /* Translates an NP index into a PPP protocol number */
 303 static const int npindex_to_proto[NUM_NP] = {
 304         PPP_IP,
 305         PPP_IPV6,
 306         PPP_IPX,
 307         PPP_AT,
 308         PPP_MPLS_UC,
 309         PPP_MPLS_MC,
 310 };
 311
 312 /* Translates an ethertype into an NP index */
 313 static inline int ethertype_to_npindex(int ethertype)
 314 {
 315         switch (ethertype) {
 316         case ETH_P_IP:
 317                 return NP_IP;
 318         case ETH_P_IPV6:
 319                 return NP_IPV6;
 320         case ETH_P_IPX:
 321                 return NP_IPX;
 322         case ETH_P_PPPTALK:
 323         case ETH_P_ATALK:
 324                 return NP_AT;
 325         case ETH_P_MPLS_UC:
 326                 return NP_MPLS_UC;
 327         case ETH_P_MPLS_MC:
 328                 return NP_MPLS_MC;
 329         }
 330         return -1;
 331 }
 332
 333 /* Translates an NP index into an ethertype */
 334 static const int npindex_to_ethertype[NUM_NP] = {
 335         ETH_P_IP,
 336         ETH_P_IPV6,
 337         ETH_P_IPX,
 338         ETH_P_PPPTALK,
 339         ETH_P_MPLS_UC,
 340         ETH_P_MPLS_MC,
 341 };
 342
 343 /*
 344  * Locking shorthand.
 345  */
 346 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 347 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 348 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 349 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 350 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 351                                      ppp_recv_lock(ppp); } while (0)
 352 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 353                                      ppp_xmit_unlock(ppp); } while (0)
 354
 355 /*
 356  * /dev/ppp device routines.
 357  * The /dev/ppp device is used by pppd to control the ppp unit.
 358  * It supports the read, write, ioctl and poll functions.
 359  * Open instances of /dev/ppp can be in one of three states:
 360  * unattached, attached to a ppp unit, or attached to a ppp channel.
 361  */
 362 static int ppp_open(struct inode *inode, struct file *file)
 363 {
 364         cycle_kernel_lock();
 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
 407         ret = count;
 408
 409         if (!pf)
 410                 return -ENXIO;
 411         add_wait_queue(&pf->rwait, &wait);
 412         for (;;) {
 413                 set_current_state(TASK_INTERRUPTIBLE);
 414                 skb = skb_dequeue(&pf->rq);
 415                 if (skb)
 416                         break;
 417                 ret = 0;
 418                 if (pf->dead)
 419                         break;
 420                 if (pf->kind == INTERFACE) {
 421                         /*
 422                          * Return 0 (EOF) on an interface that has no
 423                          * channels connected, unless it is looping
 424                          * network traffic (demand mode).
 425                          */
 426                         struct ppp *ppp = PF_TO_PPP(pf);
 427                         if (ppp->n_channels == 0
 428                             && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 429                                 break;
 430                 }
 431                 ret = -EAGAIN;
 432                 if (file->f_flags & O_NONBLOCK)
 433                         break;
 434                 ret = -ERESTARTSYS;
 435                 if (signal_pending(current))
 436                         break;
 437                 schedule();
 438         }
 439         set_current_state(TASK_RUNNING);
 440         remove_wait_queue(&pf->rwait, &wait);
 441
 442         if (!skb)
 443                 goto out;
 444
 445         ret = -EOVERFLOW;
 446         if (skb->len > count)
 447                 goto outf;
 448         ret = -EFAULT;
 449         if (copy_to_user(buf, skb->data, skb->len))
 450                 goto outf;
 451         ret = skb->len;
 452
 453  outf:
 454         kfree_skb(skb);
 455  out:
 456         return ret;
 457 }
 458
 459 static ssize_t ppp_write(struct file *file, const char __user *buf,
 460                          size_t count, loff_t *ppos)
 461 {
 462         struct ppp_file *pf = file->private_data;
 463         struct sk_buff *skb;
 464         ssize_t ret;
 465
 466         if (!pf)
 467                 return -ENXIO;
 468         ret = -ENOMEM;
 469         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 470         if (!skb)
 471                 goto out;
 472         skb_reserve(skb, pf->hdrlen);
 473         ret = -EFAULT;
 474         if (copy_from_user(skb_put(skb, count), buf, count)) {
 475                 kfree_skb(skb);
 476                 goto out;
 477         }
 478
 479         skb_queue_tail(&pf->xq, skb);
 480
 481         switch (pf->kind) {
 482         case INTERFACE:
 483                 ppp_xmit_process(PF_TO_PPP(pf));
 484                 break;
 485         case CHANNEL:
 486                 ppp_channel_push(PF_TO_CHANNEL(pf));
 487                 break;
 488         }
 489
 490         ret = count;
 491
 492  out:
 493         return ret;
 494 }
 495
 496 /* No kernel lock - fine */
 497 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 498 {
 499         struct ppp_file *pf = file->private_data;
 500         unsigned int mask;
 501
 502         if (!pf)
 503                 return 0;
 504         poll_wait(file, &pf->rwait, wait);
 505         mask = POLLOUT | POLLWRNORM;
 506         if (skb_peek(&pf->rq))
 507                 mask |= POLLIN | POLLRDNORM;
 508         if (pf->dead)
 509                 mask |= POLLHUP;
 510         else if (pf->kind == INTERFACE) {
 511                 /* see comment in ppp_read */
 512                 struct ppp *ppp = PF_TO_PPP(pf);
 513                 if (ppp->n_channels == 0
 514                     && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 515                         mask |= POLLIN | POLLRDNORM;
 516         }
 517
 518         return mask;
 519 }
 520
 521 #ifdef CONFIG_PPP_FILTER
 522 static int get_filter(void __user *arg, struct sock_filter **p)
 523 {
 524         struct sock_fprog uprog;
 525         struct sock_filter *code = NULL;
 526         int len, err;
 527
 528         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 529                 return -EFAULT;
 530
 531         if (!uprog.len) {
 532                 *p = NULL;
 533                 return 0;
 534         }
 535
 536         len = uprog.len * sizeof(struct sock_filter);
 537         code = kmalloc(len, GFP_KERNEL);
 538         if (code == NULL)
 539                 return -ENOMEM;
 540
 541         if (copy_from_user(code, uprog.filter, len)) {
 542                 kfree(code);
 543                 return -EFAULT;
 544         }
 545
 546         err = sk_chk_filter(code, uprog.len);
 547         if (err) {
 548                 kfree(code);
 549                 return err;
 550         }
 551
 552         *p = code;
 553         return uprog.len;
 554 }
 555 #endif /* CONFIG_PPP_FILTER */
 556
 557 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 558 {
 559         struct ppp_file *pf = file->private_data;
 560         struct ppp *ppp;
 561         int err = -EFAULT, val, val2, i;
 562         struct ppp_idle idle;
 563         struct npioctl npi;
 564         int unit, cflags;
 565         struct slcompress *vj;
 566         void __user *argp = (void __user *)arg;
 567         int __user *p = argp;
 568
 569         if (!pf)
 570                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
 571                                         pf, file, cmd, arg);
 572
 573         if (cmd == PPPIOCDETACH) {
 574                 /*
 575                  * We have to be careful here... if the file descriptor
 576                  * has been dup'd, we could have another process in the
 577                  * middle of a poll using the same file *, so we had
 578                  * better not free the interface data structures -
 579                  * instead we fail the ioctl.  Even in this case, we
 580                  * shut down the interface if we are the owner of it.
 581                  * Actually, we should get rid of PPPIOCDETACH, userland
 582                  * (i.e. pppd) could achieve the same effect by closing
 583                  * this fd and reopening /dev/ppp.
 584                  */
 585                 err = -EINVAL;
 586                 lock_kernel();
 587                 if (pf->kind == INTERFACE) {
 588                         ppp = PF_TO_PPP(pf);
 589                         if (file == ppp->owner)
 590                                 ppp_shutdown_interface(ppp);
 591                 }
 592                 if (atomic_long_read(&file->f_count) <= 2) {
 593                         ppp_release(NULL, file);
 594                         err = 0;
 595                 } else
 596                         printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
 597                                atomic_long_read(&file->f_count));
 598                 unlock_kernel();
 599                 return err;
 600         }
 601
 602         if (pf->kind == CHANNEL) {
 603                 struct channel *pch;
 604                 struct ppp_channel *chan;
 605
 606                 lock_kernel();
 607                 pch = PF_TO_CHANNEL(pf);
 608
 609                 switch (cmd) {
 610                 case PPPIOCCONNECT:
 611                         if (get_user(unit, p))
 612                                 break;
 613                         err = ppp_connect_channel(pch, unit);
 614                         break;
 615
 616                 case PPPIOCDISCONN:
 617                         err = ppp_disconnect_channel(pch);
 618                         break;
 619
 620                 default:
 621                         down_read(&pch->chan_sem);
 622                         chan = pch->chan;
 623                         err = -ENOTTY;
 624                         if (chan && chan->ops->ioctl)
 625                                 err = chan->ops->ioctl(chan, cmd, arg);
 626                         up_read(&pch->chan_sem);
 627                 }
 628                 unlock_kernel();
 629                 return err;
 630         }
 631
 632         if (pf->kind != INTERFACE) {
 633                 /* can't happen */
 634                 printk(KERN_ERR "PPP: not interface or channel??\n");
 635                 return -EINVAL;
 636         }
 637
 638         lock_kernel();
 639         ppp = PF_TO_PPP(pf);
 640         switch (cmd) {
 641         case PPPIOCSMRU:
 642                 if (get_user(val, p))
 643                         break;
 644                 ppp->mru = val;
 645                 err = 0;
 646                 break;
 647
 648         case PPPIOCSFLAGS:
 649                 if (get_user(val, p))
 650                         break;
 651                 ppp_lock(ppp);
 652                 cflags = ppp->flags & ~val;
 653                 ppp->flags = val & SC_FLAG_BITS;
 654                 ppp_unlock(ppp);
 655                 if (cflags & SC_CCP_OPEN)
 656                         ppp_ccp_closed(ppp);
 657                 err = 0;
 658                 break;
 659
 660         case PPPIOCGFLAGS:
 661                 val = ppp->flags | ppp->xstate | ppp->rstate;
 662                 if (put_user(val, p))
 663                         break;
 664                 err = 0;
 665                 break;
 666
 667         case PPPIOCSCOMPRESS:
 668                 err = ppp_set_compress(ppp, arg);
 669                 break;
 670
 671         case PPPIOCGUNIT:
 672                 if (put_user(ppp->file.index, p))
 673                         break;
 674                 err = 0;
 675                 break;
 676
 677         case PPPIOCSDEBUG:
 678                 if (get_user(val, p))
 679                         break;
 680                 ppp->debug = val;
 681                 err = 0;
 682                 break;
 683
 684         case PPPIOCGDEBUG:
 685                 if (put_user(ppp->debug, p))
 686                         break;
 687                 err = 0;
 688                 break;
 689
 690         case PPPIOCGIDLE:
 691                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 692                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 693                 if (copy_to_user(argp, &idle, sizeof(idle)))
 694                         break;
 695                 err = 0;
 696                 break;
 697
 698         case PPPIOCSMAXCID:
 699                 if (get_user(val, p))
 700                         break;
 701                 val2 = 15;
 702                 if ((val >> 16) != 0) {
 703                         val2 = val >> 16;
 704                         val &= 0xffff;
 705                 }
 706                 vj = slhc_init(val2+1, val+1);
 707                 if (!vj) {
 708                         printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
 709                         err = -ENOMEM;
 710                         break;
 711                 }
 712                 ppp_lock(ppp);
 713                 if (ppp->vj)
 714                         slhc_free(ppp->vj);
 715                 ppp->vj = vj;
 716                 ppp_unlock(ppp);
 717                 err = 0;
 718                 break;
 719
 720         case PPPIOCGNPMODE:
 721         case PPPIOCSNPMODE:
 722                 if (copy_from_user(&npi, argp, sizeof(npi)))
 723                         break;
 724                 err = proto_to_npindex(npi.protocol);
 725                 if (err < 0)
 726                         break;
 727                 i = err;
 728                 if (cmd == PPPIOCGNPMODE) {
 729                         err = -EFAULT;
 730                         npi.mode = ppp->npmode[i];
 731                         if (copy_to_user(argp, &npi, sizeof(npi)))
 732                                 break;
 733                 } else {
 734                         ppp->npmode[i] = npi.mode;
 735                         /* we may be able to transmit more packets now (??) */
 736                         netif_wake_queue(ppp->dev);
 737                 }
 738                 err = 0;
 739                 break;
 740
 741 #ifdef CONFIG_PPP_FILTER
 742         case PPPIOCSPASS:
 743         {
 744                 struct sock_filter *code;
 745                 err = get_filter(argp, &code);
 746                 if (err >= 0) {
 747                         ppp_lock(ppp);
 748                         kfree(ppp->pass_filter);
 749                         ppp->pass_filter = code;
 750                         ppp->pass_len = err;
 751                         ppp_unlock(ppp);
 752                         err = 0;
 753                 }
 754                 break;
 755         }
 756         case PPPIOCSACTIVE:
 757         {
 758                 struct sock_filter *code;
 759                 err = get_filter(argp, &code);
 760                 if (err >= 0) {
 761                         ppp_lock(ppp);
 762                         kfree(ppp->active_filter);
 763                         ppp->active_filter = code;
 764                         ppp->active_len = err;
 765                         ppp_unlock(ppp);
 766                         err = 0;
 767                 }
 768                 break;
 769         }
 770 #endif /* CONFIG_PPP_FILTER */
 771
 772 #ifdef CONFIG_PPP_MULTILINK
 773         case PPPIOCSMRRU:
 774                 if (get_user(val, p))
 775                         break;
 776                 ppp_recv_lock(ppp);
 777                 ppp->mrru = val;
 778                 ppp_recv_unlock(ppp);
 779                 err = 0;
 780                 break;
 781 #endif /* CONFIG_PPP_MULTILINK */
 782
 783         default:
 784                 err = -ENOTTY;
 785         }
 786         unlock_kernel();
 787         return err;
 788 }
 789
 790 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 791                         struct file *file, unsigned int cmd, unsigned long arg)
 792 {
 793         int unit, err = -EFAULT;
 794         struct ppp *ppp;
 795         struct channel *chan;
 796         struct ppp_net *pn;
 797         int __user *p = (int __user *)arg;
 798
 799         lock_kernel();
 800         switch (cmd) {
 801         case PPPIOCNEWUNIT:
 802                 /* Create a new ppp unit */
 803                 if (get_user(unit, p))
 804                         break;
 805                 ppp = ppp_create_interface(net, unit, &err);
 806                 if (!ppp)
 807                         break;
 808                 file->private_data = &ppp->file;
 809                 ppp->owner = file;
 810                 err = -EFAULT;
 811                 if (put_user(ppp->file.index, p))
 812                         break;
 813                 err = 0;
 814                 break;
 815
 816         case PPPIOCATTACH:
 817                 /* Attach to an existing ppp unit */
 818                 if (get_user(unit, p))
 819                         break;
 820                 err = -ENXIO;
 821                 pn = ppp_pernet(net);
 822                 mutex_lock(&pn->all_ppp_mutex);
 823                 ppp = ppp_find_unit(pn, unit);
 824                 if (ppp) {
 825                         atomic_inc(&ppp->file.refcnt);
 826                         file->private_data = &ppp->file;
 827                         err = 0;
 828                 }
 829                 mutex_unlock(&pn->all_ppp_mutex);
 830                 break;
 831
 832         case PPPIOCATTCHAN:
 833                 if (get_user(unit, p))
 834                         break;
 835                 err = -ENXIO;
 836                 pn = ppp_pernet(net);
 837                 spin_lock_bh(&pn->all_channels_lock);
 838                 chan = ppp_find_channel(pn, unit);
 839                 if (chan) {
 840                         atomic_inc(&chan->file.refcnt);
 841                         file->private_data = &chan->file;
 842                         err = 0;
 843                 }
 844                 spin_unlock_bh(&pn->all_channels_lock);
 845                 break;
 846
 847         default:
 848                 err = -ENOTTY;
 849         }
 850         unlock_kernel();
 851         return err;
 852 }
 853
 854 static const struct file_operations ppp_device_fops = {
 855         .owner          = THIS_MODULE,
 856         .read           = ppp_read,
 857         .write          = ppp_write,
 858         .poll           = ppp_poll,
 859         .unlocked_ioctl = ppp_ioctl,
 860         .open           = ppp_open,
 861         .release        = ppp_release
 862 };
 863
 864 static __net_init int ppp_init_net(struct net *net)
 865 {
 866         struct ppp_net *pn;
 867         int err;
 868
 869         pn = kzalloc(sizeof(*pn), GFP_KERNEL);
 870         if (!pn)
 871                 return -ENOMEM;
 872
 873         idr_init(&pn->units_idr);
 874         mutex_init(&pn->all_ppp_mutex);
 875
 876         INIT_LIST_HEAD(&pn->all_channels);
 877         INIT_LIST_HEAD(&pn->new_channels);
 878
 879         spin_lock_init(&pn->all_channels_lock);
 880
 881         err = net_assign_generic(net, ppp_net_id, pn);
 882         if (err) {
 883                 kfree(pn);
 884                 return err;
 885         }
 886
 887         return 0;
 888 }
 889
 890 static __net_exit void ppp_exit_net(struct net *net)
 891 {
 892         struct ppp_net *pn;
 893
 894         pn = net_generic(net, ppp_net_id);
 895         idr_destroy(&pn->units_idr);
 896         /*
 897          * if someone has cached our net then
 898          * further net_generic call will return NULL
 899          */
 900         net_assign_generic(net, ppp_net_id, NULL);
 901         kfree(pn);
 902 }
 903
 904 static struct pernet_operations ppp_net_ops = {
 905         .init = ppp_init_net,
 906         .exit = ppp_exit_net,
 907 };
 908
 909 #define PPP_MAJOR       108
 910
 911 /* Called at boot time if ppp is compiled into the kernel,
 912    or at module load time (from init_module) if compiled as a module. */
 913 static int __init ppp_init(void)
 914 {
 915         int err;
 916
 917         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
 918
 919         err = register_pernet_gen_device(&ppp_net_id, &ppp_net_ops);
 920         if (err) {
 921                 printk(KERN_ERR "failed to register PPP pernet device (%d)\n", err);
 922                 goto out;
 923         }
 924
 925         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 926         if (err) {
 927                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
 928                 goto out_net;
 929         }
 930
 931         ppp_class = class_create(THIS_MODULE, "ppp");
 932         if (IS_ERR(ppp_class)) {
 933                 err = PTR_ERR(ppp_class);
 934                 goto out_chrdev;
 935         }
 936
 937         /* not a big deal if we fail here :-) */
 938         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 939
 940         return 0;
 941
 942 out_chrdev:
 943         unregister_chrdev(PPP_MAJOR, "ppp");
 944 out_net:
 945         unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
 946 out:
 947         return err;
 948 }
 949
 950 /*
 951  * Network interface unit routines.
 952  */
 953 static int
 954 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 955 {
 956         struct ppp *ppp = netdev_priv(dev);
 957         int npi, proto;
 958         unsigned char *pp;
 959
 960         npi = ethertype_to_npindex(ntohs(skb->protocol));
 961         if (npi < 0)
 962                 goto outf;
 963
 964         /* Drop, accept or reject the packet */
 965         switch (ppp->npmode[npi]) {
 966         case NPMODE_PASS:
 967                 break;
 968         case NPMODE_QUEUE:
 969                 /* it would be nice to have a way to tell the network
 970                    system to queue this one up for later. */
 971                 goto outf;
 972         case NPMODE_DROP:
 973         case NPMODE_ERROR:
 974                 goto outf;
 975         }
 976
 977         /* Put the 2-byte PPP protocol number on the front,
 978            making sure there is room for the address and control fields. */
 979         if (skb_cow_head(skb, PPP_HDRLEN))
 980                 goto outf;
 981
 982         pp = skb_push(skb, 2);
 983         proto = npindex_to_proto[npi];
 984         pp[0] = proto >> 8;
 985         pp[1] = proto;
 986
 987         netif_stop_queue(dev);
 988         skb_queue_tail(&ppp->file.xq, skb);
 989         ppp_xmit_process(ppp);
 990         return 0;
 991
 992  outf:
 993         kfree_skb(skb);
 994         ++dev->stats.tx_dropped;
 995         return 0;
 996 }
 997
 998 static int
 999 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1000 {
1001         struct ppp *ppp = netdev_priv(dev);
1002         int err = -EFAULT;
1003         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1004         struct ppp_stats stats;
1005         struct ppp_comp_stats cstats;
1006         char *vers;
1007
1008         switch (cmd) {
1009         case SIOCGPPPSTATS:
1010                 ppp_get_stats(ppp, &stats);
1011                 if (copy_to_user(addr, &stats, sizeof(stats)))
1012                         break;
1013                 err = 0;
1014                 break;
1015
1016         case SIOCGPPPCSTATS:
1017                 memset(&cstats, 0, sizeof(cstats));
1018                 if (ppp->xc_state)
1019                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1020                 if (ppp->rc_state)
1021                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1022                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1023                         break;
1024                 err = 0;
1025                 break;
1026
1027         case SIOCGPPPVER:
1028                 vers = PPP_VERSION;
1029                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1030                         break;
1031                 err = 0;
1032                 break;
1033
1034         default:
1035                 err = -EINVAL;
1036         }
1037
1038         return err;
1039 }
1040
1041 static const struct net_device_ops ppp_netdev_ops = {
1042         .ndo_start_xmit = ppp_start_xmit,
1043         .ndo_do_ioctl   = ppp_net_ioctl,
1044 };
1045
1046 static void ppp_setup(struct net_device *dev)
1047 {
1048         dev->netdev_ops = &ppp_netdev_ops;
1049         dev->hard_header_len = PPP_HDRLEN;
1050         dev->mtu = PPP_MTU;
1051         dev->addr_len = 0;
1052         dev->tx_queue_len = 3;
1053         dev->type = ARPHRD_PPP;
1054         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1055         dev->features |= NETIF_F_NETNS_LOCAL;
1056 }
1057
1058 /*
1059  * Transmit-side routines.
1060  */
1061
1062 /*
1063  * Called to do any work queued up on the transmit side
1064  * that can now be done.
1065  */
1066 static void
1067 ppp_xmit_process(struct ppp *ppp)
1068 {
1069         struct sk_buff *skb;
1070
1071         ppp_xmit_lock(ppp);
1072         if (!ppp->closing) {
1073                 ppp_push(ppp);
1074                 while (!ppp->xmit_pending
1075                        && (skb = skb_dequeue(&ppp->file.xq)))
1076                         ppp_send_frame(ppp, skb);
1077                 /* If there's no work left to do, tell the core net
1078                    code that we can accept some more. */
1079                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1080                         netif_wake_queue(ppp->dev);
1081         }
1082         ppp_xmit_unlock(ppp);
1083 }
1084
1085 static inline struct sk_buff *
1086 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1087 {
1088         struct sk_buff *new_skb;
1089         int len;
1090         int new_skb_size = ppp->dev->mtu +
1091                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1092         int compressor_skb_size = ppp->dev->mtu +
1093                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1094         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1095         if (!new_skb) {
1096                 if (net_ratelimit())
1097                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1098                 return NULL;
1099         }
1100         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1101                 skb_reserve(new_skb,
1102                             ppp->dev->hard_header_len - PPP_HDRLEN);
1103
1104         /* compressor still expects A/C bytes in hdr */
1105         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1106                                    new_skb->data, skb->len + 2,
1107                                    compressor_skb_size);
1108         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1109                 kfree_skb(skb);
1110                 skb = new_skb;
1111                 skb_put(skb, len);
1112                 skb_pull(skb, 2);       /* pull off A/C bytes */
1113         } else if (len == 0) {
1114                 /* didn't compress, or CCP not up yet */
1115                 kfree_skb(new_skb);
1116                 new_skb = skb;
1117         } else {
1118                 /*
1119                  * (len < 0)
1120                  * MPPE requires that we do not send unencrypted
1121                  * frames.  The compressor will return -1 if we
1122                  * should drop the frame.  We cannot simply test
1123                  * the compress_proto because MPPE and MPPC share
1124                  * the same number.
1125                  */
1126                 if (net_ratelimit())
1127                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1128                 kfree_skb(skb);
1129                 kfree_skb(new_skb);
1130                 new_skb = NULL;
1131         }
1132         return new_skb;
1133 }
1134
1135 /*
1136  * Compress and send a frame.
1137  * The caller should have locked the xmit path,
1138  * and xmit_pending should be 0.
1139  */
1140 static void
1141 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1142 {
1143         int proto = PPP_PROTO(skb);
1144         struct sk_buff *new_skb;
1145         int len;
1146         unsigned char *cp;
1147
1148         if (proto < 0x8000) {
1149 #ifdef CONFIG_PPP_FILTER
1150                 /* check if we should pass this packet */
1151                 /* the filter instructions are constructed assuming
1152                    a four-byte PPP header on each packet */
1153                 *skb_push(skb, 2) = 1;
1154                 if (ppp->pass_filter
1155                     && sk_run_filter(skb, ppp->pass_filter,
1156                                      ppp->pass_len) == 0) {
1157                         if (ppp->debug & 1)
1158                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1159                         kfree_skb(skb);
1160                         return;
1161                 }
1162                 /* if this packet passes the active filter, record the time */
1163                 if (!(ppp->active_filter
1164                       && sk_run_filter(skb, ppp->active_filter,
1165                                        ppp->active_len) == 0))
1166                         ppp->last_xmit = jiffies;
1167                 skb_pull(skb, 2);
1168 #else
1169                 /* for data packets, record the time */
1170                 ppp->last_xmit = jiffies;
1171 #endif /* CONFIG_PPP_FILTER */
1172         }
1173
1174         ++ppp->dev->stats.tx_packets;
1175         ppp->dev->stats.tx_bytes += skb->len - 2;
1176
1177         switch (proto) {
1178         case PPP_IP:
1179                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1180                         break;
1181                 /* try to do VJ TCP header compression */
1182                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1183                                     GFP_ATOMIC);
1184                 if (!new_skb) {
1185                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1186                         goto drop;
1187                 }
1188                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1189                 cp = skb->data + 2;
1190                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1191                                     new_skb->data + 2, &cp,
1192                                     !(ppp->flags & SC_NO_TCP_CCID));
1193                 if (cp == skb->data + 2) {
1194                         /* didn't compress */
1195                         kfree_skb(new_skb);
1196                 } else {
1197                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1198                                 proto = PPP_VJC_COMP;
1199                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1200                         } else {
1201                                 proto = PPP_VJC_UNCOMP;
1202                                 cp[0] = skb->data[2];
1203                         }
1204                         kfree_skb(skb);
1205                         skb = new_skb;
1206                         cp = skb_put(skb, len + 2);
1207                         cp[0] = 0;
1208                         cp[1] = proto;
1209                 }
1210                 break;
1211
1212         case PPP_CCP:
1213                 /* peek at outbound CCP frames */
1214                 ppp_ccp_peek(ppp, skb, 0);
1215                 break;
1216         }
1217
1218         /* try to do packet compression */
1219         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
1220             && proto != PPP_LCP && proto != PPP_CCP) {
1221                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1222                         if (net_ratelimit())
1223                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1224                         goto drop;
1225                 }
1226                 skb = pad_compress_skb(ppp, skb);
1227                 if (!skb)
1228                         goto drop;
1229         }
1230
1231         /*
1232          * If we are waiting for traffic (demand dialling),
1233          * queue it up for pppd to receive.
1234          */
1235         if (ppp->flags & SC_LOOP_TRAFFIC) {
1236                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1237                         goto drop;
1238                 skb_queue_tail(&ppp->file.rq, skb);
1239                 wake_up_interruptible(&ppp->file.rwait);
1240                 return;
1241         }
1242
1243         ppp->xmit_pending = skb;
1244         ppp_push(ppp);
1245         return;
1246
1247  drop:
1248         kfree_skb(skb);
1249         ++ppp->dev->stats.tx_errors;
1250 }
1251
1252 /*
1253  * Try to send the frame in xmit_pending.
1254  * The caller should have the xmit path locked.
1255  */
1256 static void
1257 ppp_push(struct ppp *ppp)
1258 {
1259         struct list_head *list;
1260         struct channel *pch;
1261         struct sk_buff *skb = ppp->xmit_pending;
1262
1263         if (!skb)
1264                 return;
1265
1266         list = &ppp->channels;
1267         if (list_empty(list)) {
1268                 /* nowhere to send the packet, just drop it */
1269                 ppp->xmit_pending = NULL;
1270                 kfree_skb(skb);
1271                 return;
1272         }
1273
1274         if ((ppp->flags & SC_MULTILINK) == 0) {
1275                 /* not doing multilink: send it down the first channel */
1276                 list = list->next;
1277                 pch = list_entry(list, struct channel, clist);
1278
1279                 spin_lock_bh(&pch->downl);
1280                 if (pch->chan) {
1281                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1282                                 ppp->xmit_pending = NULL;
1283                 } else {
1284                         /* channel got unregistered */
1285                         kfree_skb(skb);
1286                         ppp->xmit_pending = NULL;
1287                 }
1288                 spin_unlock_bh(&pch->downl);
1289                 return;
1290         }
1291
1292 #ifdef CONFIG_PPP_MULTILINK
1293         /* Multilink: fragment the packet over as many links
1294            as can take the packet at the moment. */
1295         if (!ppp_mp_explode(ppp, skb))
1296                 return;
1297 #endif /* CONFIG_PPP_MULTILINK */
1298
1299         ppp->xmit_pending = NULL;
1300         kfree_skb(skb);
1301 }
1302
1303 #ifdef CONFIG_PPP_MULTILINK
1304 /*
1305  * Divide a packet to be transmitted into fragments and
1306  * send them out the individual links.
1307  */
1308 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1309 {
1310         int len, fragsize;
1311         int i, bits, hdrlen, mtu;
1312         int flen;
1313         int navail, nfree;
1314         int nbigger;
1315         unsigned char *p, *q;
1316         struct list_head *list;
1317         struct channel *pch;
1318         struct sk_buff *frag;
1319         struct ppp_channel *chan;
1320
1321         nfree = 0;      /* # channels which have no packet already queued */
1322         navail = 0;     /* total # of usable channels (not deregistered) */
1323         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1324         i = 0;
1325         list_for_each_entry(pch, &ppp->channels, clist) {
1326                 navail += pch->avail = (pch->chan != NULL);
1327                 if (pch->avail) {
1328                         if (skb_queue_empty(&pch->file.xq) ||
1329                             !pch->had_frag) {
1330                                 pch->avail = 2;
1331                                 ++nfree;
1332                         }
1333                         if (!pch->had_frag && i < ppp->nxchan)
1334                                 ppp->nxchan = i;
1335                 }
1336                 ++i;
1337         }
1338
1339         /*
1340          * Don't start sending this packet unless at least half of
1341          * the channels are free.  This gives much better TCP
1342          * performance if we have a lot of channels.
1343          */
1344         if (nfree == 0 || nfree < navail / 2)
1345                 return 0;       /* can't take now, leave it in xmit_pending */
1346
1347         /* Do protocol field compression (XXX this should be optional) */
1348         p = skb->data;
1349         len = skb->len;
1350         if (*p == 0) {
1351                 ++p;
1352                 --len;
1353         }
1354
1355         /*
1356          * Decide on fragment size.
1357          * We create a fragment for each free channel regardless of
1358          * how small they are (i.e. even 0 length) in order to minimize
1359          * the time that it will take to detect when a channel drops
1360          * a fragment.
1361          */
1362         fragsize = len;
1363         if (nfree > 1)
1364                 fragsize = DIV_ROUND_UP(fragsize, nfree);
1365         /* nbigger channels get fragsize bytes, the rest get fragsize-1,
1366            except if nbigger==0, then they all get fragsize. */
1367         nbigger = len % nfree;
1368
1369         /* skip to the channel after the one we last used
1370            and start at that one */
1371         list = &ppp->channels;
1372         for (i = 0; i < ppp->nxchan; ++i) {
1373                 list = list->next;
1374                 if (list == &ppp->channels) {
1375                         i = 0;
1376                         break;
1377                 }
1378         }
1379
1380         /* create a fragment for each channel */
1381         bits = B;
1382         while (nfree > 0 || len > 0) {
1383                 list = list->next;
1384                 if (list == &ppp->channels) {
1385                         i = 0;
1386                         continue;
1387                 }
1388                 pch = list_entry(list, struct channel, clist);
1389                 ++i;
1390                 if (!pch->avail)
1391                         continue;
1392
1393                 /*
1394                  * Skip this channel if it has a fragment pending already and
1395                  * we haven't given a fragment to all of the free channels.
1396                  */
1397                 if (pch->avail == 1) {
1398                         if (nfree > 0)
1399                                 continue;
1400                 } else {
1401                         --nfree;
1402                         pch->avail = 1;
1403                 }
1404
1405                 /* check the channel's mtu and whether it is still attached. */
1406                 spin_lock_bh(&pch->downl);
1407                 if (pch->chan == NULL) {
1408                         /* can't use this channel, it's being deregistered */
1409                         spin_unlock_bh(&pch->downl);
1410                         pch->avail = 0;
1411                         if (--navail == 0)
1412                                 break;
1413                         continue;
1414                 }
1415
1416                 /*
1417                  * Create a fragment for this channel of
1418                  * min(max(mtu+2-hdrlen, 4), fragsize, len) bytes.
1419                  * If mtu+2-hdrlen < 4, that is a ridiculously small
1420                  * MTU, so we use mtu = 2 + hdrlen.
1421                  */
1422                 if (fragsize > len)
1423                         fragsize = len;
1424                 flen = fragsize;
1425                 mtu = pch->chan->mtu + 2 - hdrlen;
1426                 if (mtu < 4)
1427                         mtu = 4;
1428                 if (flen > mtu)
1429                         flen = mtu;
1430                 if (flen == len && nfree == 0)
1431                         bits |= E;
1432                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1433                 if (!frag)
1434                         goto noskb;
1435                 q = skb_put(frag, flen + hdrlen);
1436
1437                 /* make the MP header */
1438                 q[0] = PPP_MP >> 8;
1439                 q[1] = PPP_MP;
1440                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1441                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1442                         q[3] = ppp->nxseq;
1443                 } else {
1444                         q[2] = bits;
1445                         q[3] = ppp->nxseq >> 16;
1446                         q[4] = ppp->nxseq >> 8;
1447                         q[5] = ppp->nxseq;
1448                 }
1449
1450                 /*
1451                  * Copy the data in.
1452                  * Unfortunately there is a bug in older versions of
1453                  * the Linux PPP multilink reconstruction code where it
1454                  * drops 0-length fragments.  Therefore we make sure the
1455                  * fragment has at least one byte of data.  Any bytes
1456                  * we add in this situation will end up as padding on the
1457                  * end of the reconstructed packet.
1458                  */
1459                 if (flen == 0)
1460                         *skb_put(frag, 1) = 0;
1461                 else
1462                         memcpy(q + hdrlen, p, flen);
1463
1464                 /* try to send it down the channel */
1465                 chan = pch->chan;
1466                 if (!skb_queue_empty(&pch->file.xq) ||
1467                     !chan->ops->start_xmit(chan, frag))
1468                         skb_queue_tail(&pch->file.xq, frag);
1469                 pch->had_frag = 1;
1470                 p += flen;
1471                 len -= flen;
1472                 ++ppp->nxseq;
1473                 bits = 0;
1474                 spin_unlock_bh(&pch->downl);
1475
1476                 if (--nbigger == 0 && fragsize > 0)
1477                         --fragsize;
1478         }
1479         ppp->nxchan = i;
1480
1481         return 1;
1482
1483  noskb:
1484         spin_unlock_bh(&pch->downl);
1485         if (ppp->debug & 1)
1486                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1487         ++ppp->dev->stats.tx_errors;
1488         ++ppp->nxseq;
1489         return 1;       /* abandon the frame */
1490 }
1491 #endif /* CONFIG_PPP_MULTILINK */
1492
1493 /*
1494  * Try to send data out on a channel.
1495  */
1496 static void
1497 ppp_channel_push(struct channel *pch)
1498 {
1499         struct sk_buff *skb;
1500         struct ppp *ppp;
1501
1502         spin_lock_bh(&pch->downl);
1503         if (pch->chan) {
1504                 while (!skb_queue_empty(&pch->file.xq)) {
1505                         skb = skb_dequeue(&pch->file.xq);
1506                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1507                                 /* put the packet back and try again later */
1508                                 skb_queue_head(&pch->file.xq, skb);
1509                                 break;
1510                         }
1511                 }
1512         } else {
1513                 /* channel got deregistered */
1514                 skb_queue_purge(&pch->file.xq);
1515         }
1516         spin_unlock_bh(&pch->downl);
1517         /* see if there is anything from the attached unit to be sent */
1518         if (skb_queue_empty(&pch->file.xq)) {
1519                 read_lock_bh(&pch->upl);
1520                 ppp = pch->ppp;
1521                 if (ppp)
1522                         ppp_xmit_process(ppp);
1523                 read_unlock_bh(&pch->upl);
1524         }
1525 }
1526
1527 /*
1528  * Receive-side routines.
1529  */
1530
1531 /* misuse a few fields of the skb for MP reconstruction */
1532 #define sequence        priority
1533 #define BEbits          cb[0]
1534
1535 static inline void
1536 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1537 {
1538         ppp_recv_lock(ppp);
1539         if (!ppp->closing)
1540                 ppp_receive_frame(ppp, skb, pch);
1541         else
1542                 kfree_skb(skb);
1543         ppp_recv_unlock(ppp);
1544 }
1545
1546 void
1547 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1548 {
1549         struct channel *pch = chan->ppp;
1550         int proto;
1551
1552         if (!pch || skb->len == 0) {
1553                 kfree_skb(skb);
1554                 return;
1555         }
1556
1557         proto = PPP_PROTO(skb);
1558         read_lock_bh(&pch->upl);
1559         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1560                 /* put it on the channel queue */
1561                 skb_queue_tail(&pch->file.rq, skb);
1562                 /* drop old frames if queue too long */
1563                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1564                        && (skb = skb_dequeue(&pch->file.rq)))
1565                         kfree_skb(skb);
1566                 wake_up_interruptible(&pch->file.rwait);
1567         } else {
1568                 ppp_do_recv(pch->ppp, skb, pch);
1569         }
1570         read_unlock_bh(&pch->upl);
1571 }
1572
1573 /* Put a 0-length skb in the receive queue as an error indication */
1574 void
1575 ppp_input_error(struct ppp_channel *chan, int code)
1576 {
1577         struct channel *pch = chan->ppp;
1578         struct sk_buff *skb;
1579
1580         if (!pch)
1581                 return;
1582
1583         read_lock_bh(&pch->upl);
1584         if (pch->ppp) {
1585                 skb = alloc_skb(0, GFP_ATOMIC);
1586                 if (skb) {
1587                         skb->len = 0;           /* probably unnecessary */
1588                         skb->cb[0] = code;
1589                         ppp_do_recv(pch->ppp, skb, pch);
1590                 }
1591         }
1592         read_unlock_bh(&pch->upl);
1593 }
1594
1595 /*
1596  * We come in here to process a received frame.
1597  * The receive side of the ppp unit is locked.
1598  */
1599 static void
1600 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1601 {
1602         if (pskb_may_pull(skb, 2)) {
1603 #ifdef CONFIG_PPP_MULTILINK
1604                 /* XXX do channel-level decompression here */
1605                 if (PPP_PROTO(skb) == PPP_MP)
1606                         ppp_receive_mp_frame(ppp, skb, pch);
1607                 else
1608 #endif /* CONFIG_PPP_MULTILINK */
1609                         ppp_receive_nonmp_frame(ppp, skb);
1610                 return;
1611         }
1612
1613         if (skb->len > 0)
1614                 /* note: a 0-length skb is used as an error indication */
1615                 ++ppp->dev->stats.rx_length_errors;
1616
1617         kfree_skb(skb);
1618         ppp_receive_error(ppp);
1619 }
1620
1621 static void
1622 ppp_receive_error(struct ppp *ppp)
1623 {
1624         ++ppp->dev->stats.rx_errors;
1625         if (ppp->vj)
1626                 slhc_toss(ppp->vj);
1627 }
1628
1629 static void
1630 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1631 {
1632         struct sk_buff *ns;
1633         int proto, len, npi;
1634
1635         /*
1636          * Decompress the frame, if compressed.
1637          * Note that some decompressors need to see uncompressed frames
1638          * that come in as well as compressed frames.
1639          */
1640         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
1641             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1642                 skb = ppp_decompress_frame(ppp, skb);
1643
1644         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1645                 goto err;
1646
1647         proto = PPP_PROTO(skb);
1648         switch (proto) {
1649         case PPP_VJC_COMP:
1650                 /* decompress VJ compressed packets */
1651                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1652                         goto err;
1653
1654                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1655                         /* copy to a new sk_buff with more tailroom */
1656                         ns = dev_alloc_skb(skb->len + 128);
1657                         if (!ns) {
1658                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1659                                 goto err;
1660                         }
1661                         skb_reserve(ns, 2);
1662                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1663                         kfree_skb(skb);
1664                         skb = ns;
1665                 }
1666                 else
1667                         skb->ip_summed = CHECKSUM_NONE;
1668
1669                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1670                 if (len <= 0) {
1671                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1672                         goto err;
1673                 }
1674                 len += 2;
1675                 if (len > skb->len)
1676                         skb_put(skb, len - skb->len);
1677                 else if (len < skb->len)
1678                         skb_trim(skb, len);
1679                 proto = PPP_IP;
1680                 break;
1681
1682         case PPP_VJC_UNCOMP:
1683                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1684                         goto err;
1685
1686                 /* Until we fix the decompressor need to make sure
1687                  * data portion is linear.
1688                  */
1689                 if (!pskb_may_pull(skb, skb->len))
1690                         goto err;
1691
1692                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1693                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1694                         goto err;
1695                 }
1696                 proto = PPP_IP;
1697                 break;
1698
1699         case PPP_CCP:
1700                 ppp_ccp_peek(ppp, skb, 1);
1701                 break;
1702         }
1703
1704         ++ppp->dev->stats.rx_packets;
1705         ppp->dev->stats.rx_bytes += skb->len - 2;
1706
1707         npi = proto_to_npindex(proto);
1708         if (npi < 0) {
1709                 /* control or unknown frame - pass it to pppd */
1710                 skb_queue_tail(&ppp->file.rq, skb);
1711                 /* limit queue length by dropping old frames */
1712                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1713                        && (skb = skb_dequeue(&ppp->file.rq)))
1714                         kfree_skb(skb);
1715                 /* wake up any process polling or blocking on read */
1716                 wake_up_interruptible(&ppp->file.rwait);
1717
1718         } else {
1719                 /* network protocol frame - give it to the kernel */
1720
1721 #ifdef CONFIG_PPP_FILTER
1722                 /* check if the packet passes the pass and active filters */
1723                 /* the filter instructions are constructed assuming
1724                    a four-byte PPP header on each packet */
1725                 if (ppp->pass_filter || ppp->active_filter) {
1726                         if (skb_cloned(skb) &&
1727                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1728                                 goto err;
1729
1730                         *skb_push(skb, 2) = 0;
1731                         if (ppp->pass_filter
1732                             && sk_run_filter(skb, ppp->pass_filter,
1733                                              ppp->pass_len) == 0) {
1734                                 if (ppp->debug & 1)
1735                                         printk(KERN_DEBUG "PPP: inbound frame "
1736                                                "not passed\n");
1737                                 kfree_skb(skb);
1738                                 return;
1739                         }
1740                         if (!(ppp->active_filter
1741                               && sk_run_filter(skb, ppp->active_filter,
1742                                                ppp->active_len) == 0))
1743                                 ppp->last_recv = jiffies;
1744                         __skb_pull(skb, 2);
1745                 } else
1746 #endif /* CONFIG_PPP_FILTER */
1747                         ppp->last_recv = jiffies;
1748
1749                 if ((ppp->dev->flags & IFF_UP) == 0
1750                     || ppp->npmode[npi] != NPMODE_PASS) {
1751                         kfree_skb(skb);
1752                 } else {
1753                         /* chop off protocol */
1754                         skb_pull_rcsum(skb, 2);
1755                         skb->dev = ppp->dev;
1756                         skb->protocol = htons(npindex_to_ethertype[npi]);
1757                         skb_reset_mac_header(skb);
1758                         netif_rx(skb);
1759                 }
1760         }
1761         return;
1762
1763  err:
1764         kfree_skb(skb);
1765         ppp_receive_error(ppp);
1766 }
1767
1768 static struct sk_buff *
1769 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1770 {
1771         int proto = PPP_PROTO(skb);
1772         struct sk_buff *ns;
1773         int len;
1774
1775         /* Until we fix all the decompressor's need to make sure
1776          * data portion is linear.
1777          */
1778         if (!pskb_may_pull(skb, skb->len))
1779                 goto err;
1780
1781         if (proto == PPP_COMP) {
1782                 int obuff_size;
1783
1784                 switch(ppp->rcomp->compress_proto) {
1785                 case CI_MPPE:
1786                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1787                         break;
1788                 default:
1789                         obuff_size = ppp->mru + PPP_HDRLEN;
1790                         break;
1791                 }
1792
1793                 ns = dev_alloc_skb(obuff_size);
1794                 if (!ns) {
1795                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1796                         goto err;
1797                 }
1798                 /* the decompressor still expects the A/C bytes in the hdr */
1799                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1800                                 skb->len + 2, ns->data, obuff_size);
1801                 if (len < 0) {
1802                         /* Pass the compressed frame to pppd as an
1803                            error indication. */
1804                         if (len == DECOMP_FATALERROR)
1805                                 ppp->rstate |= SC_DC_FERROR;
1806                         kfree_skb(ns);
1807                         goto err;
1808                 }
1809
1810                 kfree_skb(skb);
1811                 skb = ns;
1812                 skb_put(skb, len);
1813                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1814
1815         } else {
1816                 /* Uncompressed frame - pass to decompressor so it
1817                    can update its dictionary if necessary. */
1818                 if (ppp->rcomp->incomp)
1819                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1820                                            skb->len + 2);
1821         }
1822
1823         return skb;
1824
1825  err:
1826         ppp->rstate |= SC_DC_ERROR;
1827         ppp_receive_error(ppp);
1828         return skb;
1829 }
1830
1831 #ifdef CONFIG_PPP_MULTILINK
1832 /*
1833  * Receive a multilink frame.
1834  * We put it on the reconstruction queue and then pull off
1835  * as many completed frames as we can.
1836  */
1837 static void
1838 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1839 {
1840         u32 mask, seq;
1841         struct channel *ch;
1842         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1843
1844         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1845                 goto err;               /* no good, throw it away */
1846
1847         /* Decode sequence number and begin/end bits */
1848         if (ppp->flags & SC_MP_SHORTSEQ) {
1849                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1850                 mask = 0xfff;
1851         } else {
1852                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1853                 mask = 0xffffff;
1854         }
1855         skb->BEbits = skb->data[2];
1856         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1857
1858         /*
1859          * Do protocol ID decompression on the first fragment of each packet.
1860          */
1861         if ((skb->BEbits & B) && (skb->data[0] & 1))
1862                 *skb_push(skb, 1) = 0;
1863
1864         /*
1865          * Expand sequence number to 32 bits, making it as close
1866          * as possible to ppp->minseq.
1867          */
1868         seq |= ppp->minseq & ~mask;
1869         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1870                 seq += mask + 1;
1871         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1872                 seq -= mask + 1;        /* should never happen */
1873         skb->sequence = seq;
1874         pch->lastseq = seq;
1875
1876         /*
1877          * If this packet comes before the next one we were expecting,
1878          * drop it.
1879          */
1880         if (seq_before(seq, ppp->nextseq)) {
1881                 kfree_skb(skb);
1882                 ++ppp->dev->stats.rx_dropped;
1883                 ppp_receive_error(ppp);
1884                 return;
1885         }
1886
1887         /*
1888          * Reevaluate minseq, the minimum over all channels of the
1889          * last sequence number received on each channel.  Because of
1890          * the increasing sequence number rule, we know that any fragment
1891          * before `minseq' which hasn't arrived is never going to arrive.
1892          * The list of channels can't change because we have the receive
1893          * side of the ppp unit locked.
1894          */
1895         list_for_each_entry(ch, &ppp->channels, clist) {
1896                 if (seq_before(ch->lastseq, seq))
1897                         seq = ch->lastseq;
1898         }
1899         if (seq_before(ppp->minseq, seq))
1900                 ppp->minseq = seq;
1901
1902         /* Put the fragment on the reconstruction queue */
1903         ppp_mp_insert(ppp, skb);
1904
1905         /* If the queue is getting long, don't wait any longer for packets
1906            before the start of the queue. */
1907         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1908                 struct sk_buff *skb = skb_peek(&ppp->mrq);
1909                 if (seq_before(ppp->minseq, skb->sequence))
1910                         ppp->minseq = skb->sequence;
1911         }
1912
1913         /* Pull completed packets off the queue and receive them. */
1914         while ((skb = ppp_mp_reconstruct(ppp)))
1915                 ppp_receive_nonmp_frame(ppp, skb);
1916
1917         return;
1918
1919  err:
1920         kfree_skb(skb);
1921         ppp_receive_error(ppp);
1922 }
1923
1924 /*
1925  * Insert a fragment on the MP reconstruction queue.
1926  * The queue is ordered by increasing sequence number.
1927  */
1928 static void
1929 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1930 {
1931         struct sk_buff *p;
1932         struct sk_buff_head *list = &ppp->mrq;
1933         u32 seq = skb->sequence;
1934
1935         /* N.B. we don't need to lock the list lock because we have the
1936            ppp unit receive-side lock. */
1937         skb_queue_walk(list, p) {
1938                 if (seq_before(seq, p->sequence))
1939                         break;
1940         }
1941         __skb_queue_before(list, p, skb);
1942 }
1943
1944 /*
1945  * Reconstruct a packet from the MP fragment queue.
1946  * We go through increasing sequence numbers until we find a
1947  * complete packet, or we get to the sequence number for a fragment
1948  * which hasn't arrived but might still do so.
1949  */
1950 static struct sk_buff *
1951 ppp_mp_reconstruct(struct ppp *ppp)
1952 {
1953         u32 seq = ppp->nextseq;
1954         u32 minseq = ppp->minseq;
1955         struct sk_buff_head *list = &ppp->mrq;
1956         struct sk_buff *p, *next;
1957         struct sk_buff *head, *tail;
1958         struct sk_buff *skb = NULL;
1959         int lost = 0, len = 0;
1960
1961         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1962                 return NULL;
1963         head = list->next;
1964         tail = NULL;
1965         for (p = head; p != (struct sk_buff *) list; p = next) {
1966                 next = p->next;
1967                 if (seq_before(p->sequence, seq)) {
1968                         /* this can't happen, anyway ignore the skb */
1969                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1970                                p->sequence, seq);
1971                         head = next;
1972                         continue;
1973                 }
1974                 if (p->sequence != seq) {
1975                         /* Fragment `seq' is missing.  If it is after
1976                            minseq, it might arrive later, so stop here. */
1977                         if (seq_after(seq, minseq))
1978                                 break;
1979                         /* Fragment `seq' is lost, keep going. */
1980                         lost = 1;
1981                         seq = seq_before(minseq, p->sequence)?
1982                                 minseq + 1: p->sequence;
1983                         next = p;
1984                         continue;
1985                 }
1986
1987                 /*
1988                  * At this point we know that all the fragments from
1989                  * ppp->nextseq to seq are either present or lost.
1990                  * Also, there are no complete packets in the queue
1991                  * that have no missing fragments and end before this
1992                  * fragment.
1993                  */
1994
1995                 /* B bit set indicates this fragment starts a packet */
1996                 if (p->BEbits & B) {
1997                         head = p;
1998                         lost = 0;
1999                         len = 0;
2000                 }
2001
2002                 len += p->len;
2003
2004                 /* Got a complete packet yet? */
2005                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
2006                         if (len > ppp->mrru + 2) {
2007                                 ++ppp->dev->stats.rx_length_errors;
2008                                 printk(KERN_DEBUG "PPP: reconstructed packet"
2009                                        " is too long (%d)\n", len);
2010                         } else if (p == head) {
2011                                 /* fragment is complete packet - reuse skb */
2012                                 tail = p;
2013                                 skb = skb_get(p);
2014                                 break;
2015                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
2016                                 ++ppp->dev->stats.rx_missed_errors;
2017                                 printk(KERN_DEBUG "PPP: no memory for "
2018                                        "reconstructed packet");
2019                         } else {
2020                                 tail = p;
2021                                 break;
2022                         }
2023                         ppp->nextseq = seq + 1;
2024                 }
2025
2026                 /*
2027                  * If this is the ending fragment of a packet,
2028                  * and we haven't found a complete valid packet yet,
2029                  * we can discard up to and including this fragment.
2030                  */
2031                 if (p->BEbits & E)
2032                         head = next;
2033
2034                 ++seq;
2035         }
2036
2037         /* If we have a complete packet, copy it all into one skb. */
2038         if (tail != NULL) {
2039                 /* If we have discarded any fragments,
2040                    signal a receive error. */
2041                 if (head->sequence != ppp->nextseq) {
2042                         if (ppp->debug & 1)
2043                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
2044                                        ppp->nextseq, head->sequence-1);
2045                         ++ppp->dev->stats.rx_dropped;
2046                         ppp_receive_error(ppp);
2047                 }
2048
2049                 if (head != tail)
2050                         /* copy to a single skb */
2051                         for (p = head; p != tail->next; p = p->next)
2052                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
2053                 ppp->nextseq = tail->sequence + 1;
2054                 head = tail->next;
2055         }
2056
2057         /* Discard all the skbuffs that we have copied the data out of
2058            or that we can't use. */
2059         while ((p = list->next) != head) {
2060                 __skb_unlink(p, list);
2061                 kfree_skb(p);
2062         }
2063
2064         return skb;
2065 }
2066 #endif /* CONFIG_PPP_MULTILINK */
2067
2068 /*
2069  * Channel interface.
2070  */
2071
2072 /* Create a new, unattached ppp channel. */
2073 int ppp_register_channel(struct ppp_channel *chan)
2074 {
2075         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2076 }
2077
2078 /* Create a new, unattached ppp channel for specified net. */
2079 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2080 {
2081         struct channel *pch;
2082         struct ppp_net *pn;
2083
2084         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2085         if (!pch)
2086                 return -ENOMEM;
2087
2088         pn = ppp_pernet(net);
2089
2090         pch->ppp = NULL;
2091         pch->chan = chan;
2092         pch->chan_net = net;
2093         chan->ppp = pch;
2094         init_ppp_file(&pch->file, CHANNEL);
2095         pch->file.hdrlen = chan->hdrlen;
2096 #ifdef CONFIG_PPP_MULTILINK
2097         pch->lastseq = -1;
2098 #endif /* CONFIG_PPP_MULTILINK */
2099         init_rwsem(&pch->chan_sem);
2100         spin_lock_init(&pch->downl);
2101         rwlock_init(&pch->upl);
2102
2103         spin_lock_bh(&pn->all_channels_lock);
2104         pch->file.index = ++pn->last_channel_index;
2105         list_add(&pch->list, &pn->new_channels);
2106         atomic_inc(&channel_count);
2107         spin_unlock_bh(&pn->all_channels_lock);
2108
2109         return 0;
2110 }
2111
2112 /*
2113  * Return the index of a channel.
2114  */
2115 int ppp_channel_index(struct ppp_channel *chan)
2116 {
2117         struct channel *pch = chan->ppp;
2118
2119         if (pch)
2120                 return pch->file.index;
2121         return -1;
2122 }
2123
2124 /*
2125  * Return the PPP unit number to which a channel is connected.
2126  */
2127 int ppp_unit_number(struct ppp_channel *chan)
2128 {
2129         struct channel *pch = chan->ppp;
2130         int unit = -1;
2131
2132         if (pch) {
2133                 read_lock_bh(&pch->upl);
2134                 if (pch->ppp)
2135                         unit = pch->ppp->file.index;
2136                 read_unlock_bh(&pch->upl);
2137         }
2138         return unit;
2139 }
2140
2141 /*
2142  * Disconnect a channel from the generic layer.
2143  * This must be called in process context.
2144  */
2145 void
2146 ppp_unregister_channel(struct ppp_channel *chan)
2147 {
2148         struct channel *pch = chan->ppp;
2149         struct ppp_net *pn;
2150
2151         if (!pch)
2152                 return;         /* should never happen */
2153
2154         chan->ppp = NULL;
2155
2156         /*
2157          * This ensures that we have returned from any calls into the
2158          * the channel's start_xmit or ioctl routine before we proceed.
2159          */
2160         down_write(&pch->chan_sem);
2161         spin_lock_bh(&pch->downl);
2162         pch->chan = NULL;
2163         spin_unlock_bh(&pch->downl);
2164         up_write(&pch->chan_sem);
2165         ppp_disconnect_channel(pch);
2166
2167         pn = ppp_pernet(pch->chan_net);
2168         spin_lock_bh(&pn->all_channels_lock);
2169         list_del(&pch->list);
2170         spin_unlock_bh(&pn->all_channels_lock);
2171
2172         pch->file.dead = 1;
2173         wake_up_interruptible(&pch->file.rwait);
2174         if (atomic_dec_and_test(&pch->file.refcnt))
2175                 ppp_destroy_channel(pch);
2176 }
2177
2178 /*
2179  * Callback from a channel when it can accept more to transmit.
2180  * This should be called at BH/softirq level, not interrupt level.
2181  */
2182 void
2183 ppp_output_wakeup(struct ppp_channel *chan)
2184 {
2185         struct channel *pch = chan->ppp;
2186
2187         if (!pch)
2188                 return;
2189         ppp_channel_push(pch);
2190 }
2191
2192 /*
2193  * Compression control.
2194  */
2195
2196 /* Process the PPPIOCSCOMPRESS ioctl. */
2197 static int
2198 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2199 {
2200         int err;
2201         struct compressor *cp, *ocomp;
2202         struct ppp_option_data data;
2203         void *state, *ostate;
2204         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2205
2206         err = -EFAULT;
2207         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2208             || (data.length <= CCP_MAX_OPTION_LENGTH
2209                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2210                 goto out;
2211         err = -EINVAL;
2212         if (data.length > CCP_MAX_OPTION_LENGTH
2213             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2214                 goto out;
2215
2216         cp = try_then_request_module(
2217                 find_compressor(ccp_option[0]),
2218                 "ppp-compress-%d", ccp_option[0]);
2219         if (!cp)
2220                 goto out;
2221
2222         err = -ENOBUFS;
2223         if (data.transmit) {
2224                 state = cp->comp_alloc(ccp_option, data.length);
2225                 if (state) {
2226                         ppp_xmit_lock(ppp);
2227                         ppp->xstate &= ~SC_COMP_RUN;
2228                         ocomp = ppp->xcomp;
2229                         ostate = ppp->xc_state;
2230                         ppp->xcomp = cp;
2231                         ppp->xc_state = state;
2232                         ppp_xmit_unlock(ppp);
2233                         if (ostate) {
2234                                 ocomp->comp_free(ostate);
2235                                 module_put(ocomp->owner);
2236                         }
2237                         err = 0;
2238                 } else
2239                         module_put(cp->owner);
2240
2241         } else {
2242                 state = cp->decomp_alloc(ccp_option, data.length);
2243                 if (state) {
2244                         ppp_recv_lock(ppp);
2245                         ppp->rstate &= ~SC_DECOMP_RUN;
2246                         ocomp = ppp->rcomp;
2247                         ostate = ppp->rc_state;
2248                         ppp->rcomp = cp;
2249                         ppp->rc_state = state;
2250                         ppp_recv_unlock(ppp);
2251                         if (ostate) {
2252                                 ocomp->decomp_free(ostate);
2253                                 module_put(ocomp->owner);
2254                         }
2255                         err = 0;
2256                 } else
2257                         module_put(cp->owner);
2258         }
2259
2260  out:
2261         return err;
2262 }
2263
2264 /*
2265  * Look at a CCP packet and update our state accordingly.
2266  * We assume the caller has the xmit or recv path locked.
2267  */
2268 static void
2269 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2270 {
2271         unsigned char *dp;
2272         int len;
2273
2274         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2275                 return; /* no header */
2276         dp = skb->data + 2;
2277
2278         switch (CCP_CODE(dp)) {
2279         case CCP_CONFREQ:
2280
2281                 /* A ConfReq starts negotiation of compression
2282                  * in one direction of transmission,
2283                  * and hence brings it down...but which way?
2284                  *
2285                  * Remember:
2286                  * A ConfReq indicates what the sender would like to receive
2287                  */
2288                 if(inbound)
2289                         /* He is proposing what I should send */
2290                         ppp->xstate &= ~SC_COMP_RUN;
2291                 else
2292                         /* I am proposing to what he should send */
2293                         ppp->rstate &= ~SC_DECOMP_RUN;
2294
2295                 break;
2296
2297         case CCP_TERMREQ:
2298         case CCP_TERMACK:
2299                 /*
2300                  * CCP is going down, both directions of transmission
2301                  */
2302                 ppp->rstate &= ~SC_DECOMP_RUN;
2303                 ppp->xstate &= ~SC_COMP_RUN;
2304                 break;
2305
2306         case CCP_CONFACK:
2307                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2308                         break;
2309                 len = CCP_LENGTH(dp);
2310                 if (!pskb_may_pull(skb, len + 2))
2311                         return;         /* too short */
2312                 dp += CCP_HDRLEN;
2313                 len -= CCP_HDRLEN;
2314                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2315                         break;
2316                 if (inbound) {
2317                         /* we will start receiving compressed packets */
2318                         if (!ppp->rc_state)
2319                                 break;
2320                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2321                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2322                                 ppp->rstate |= SC_DECOMP_RUN;
2323                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2324                         }
2325                 } else {
2326                         /* we will soon start sending compressed packets */
2327                         if (!ppp->xc_state)
2328                                 break;
2329                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2330                                         ppp->file.index, 0, ppp->debug))
2331                                 ppp->xstate |= SC_COMP_RUN;
2332                 }
2333                 break;
2334
2335         case CCP_RESETACK:
2336                 /* reset the [de]compressor */
2337                 if ((ppp->flags & SC_CCP_UP) == 0)
2338                         break;
2339                 if (inbound) {
2340                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2341                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2342                                 ppp->rstate &= ~SC_DC_ERROR;
2343                         }
2344                 } else {
2345                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2346                                 ppp->xcomp->comp_reset(ppp->xc_state);
2347                 }
2348                 break;
2349         }
2350 }
2351
2352 /* Free up compression resources. */
2353 static void
2354 ppp_ccp_closed(struct ppp *ppp)
2355 {
2356         void *xstate, *rstate;
2357         struct compressor *xcomp, *rcomp;
2358
2359         ppp_lock(ppp);
2360         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2361         ppp->xstate = 0;
2362         xcomp = ppp->xcomp;
2363         xstate = ppp->xc_state;
2364         ppp->xc_state = NULL;
2365         ppp->rstate = 0;
2366         rcomp = ppp->rcomp;
2367         rstate = ppp->rc_state;
2368         ppp->rc_state = NULL;
2369         ppp_unlock(ppp);
2370
2371         if (xstate) {
2372                 xcomp->comp_free(xstate);
2373                 module_put(xcomp->owner);
2374         }
2375         if (rstate) {
2376                 rcomp->decomp_free(rstate);
2377                 module_put(rcomp->owner);
2378         }
2379 }
2380
2381 /* List of compressors. */
2382 static LIST_HEAD(compressor_list);
2383 static DEFINE_SPINLOCK(compressor_list_lock);
2384
2385 struct compressor_entry {
2386         struct list_head list;
2387         struct compressor *comp;
2388 };
2389
2390 static struct compressor_entry *
2391 find_comp_entry(int proto)
2392 {
2393         struct compressor_entry *ce;
2394
2395         list_for_each_entry(ce, &compressor_list, list) {
2396                 if (ce->comp->compress_proto == proto)
2397                         return ce;
2398         }
2399         return NULL;
2400 }
2401
2402 /* Register a compressor */
2403 int
2404 ppp_register_compressor(struct compressor *cp)
2405 {
2406         struct compressor_entry *ce;
2407         int ret;
2408         spin_lock(&compressor_list_lock);
2409         ret = -EEXIST;
2410         if (find_comp_entry(cp->compress_proto))
2411                 goto out;
2412         ret = -ENOMEM;
2413         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2414         if (!ce)
2415                 goto out;
2416         ret = 0;
2417         ce->comp = cp;
2418         list_add(&ce->list, &compressor_list);
2419  out:
2420         spin_unlock(&compressor_list_lock);
2421         return ret;
2422 }
2423
2424 /* Unregister a compressor */
2425 void
2426 ppp_unregister_compressor(struct compressor *cp)
2427 {
2428         struct compressor_entry *ce;
2429
2430         spin_lock(&compressor_list_lock);
2431         ce = find_comp_entry(cp->compress_proto);
2432         if (ce && ce->comp == cp) {
2433                 list_del(&ce->list);
2434                 kfree(ce);
2435         }
2436         spin_unlock(&compressor_list_lock);
2437 }
2438
2439 /* Find a compressor. */
2440 static struct compressor *
2441 find_compressor(int type)
2442 {
2443         struct compressor_entry *ce;
2444         struct compressor *cp = NULL;
2445
2446         spin_lock(&compressor_list_lock);
2447         ce = find_comp_entry(type);
2448         if (ce) {
2449                 cp = ce->comp;
2450                 if (!try_module_get(cp->owner))
2451                         cp = NULL;
2452         }
2453         spin_unlock(&compressor_list_lock);
2454         return cp;
2455 }
2456
2457 /*
2458  * Miscelleneous stuff.
2459  */
2460
2461 static void
2462 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2463 {
2464         struct slcompress *vj = ppp->vj;
2465
2466         memset(st, 0, sizeof(*st));
2467         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2468         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2469         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2470         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2471         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2472         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2473         if (!vj)
2474                 return;
2475         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2476         st->vj.vjs_compressed = vj->sls_o_compressed;
2477         st->vj.vjs_searches = vj->sls_o_searches;
2478         st->vj.vjs_misses = vj->sls_o_misses;
2479         st->vj.vjs_errorin = vj->sls_i_error;
2480         st->vj.vjs_tossed = vj->sls_i_tossed;
2481         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2482         st->vj.vjs_compressedin = vj->sls_i_compressed;
2483 }
2484
2485 /*
2486  * Stuff for handling the lists of ppp units and channels
2487  * and for initialization.
2488  */
2489
2490 /*
2491  * Create a new ppp interface unit.  Fails if it can't allocate memory
2492  * or if there is already a unit with the requested number.
2493  * unit == -1 means allocate a new number.
2494  */
2495 static struct ppp *
2496 ppp_create_interface(struct net *net, int unit, int *retp)
2497 {
2498         struct ppp *ppp;
2499         struct ppp_net *pn;
2500         struct net_device *dev = NULL;
2501         int ret = -ENOMEM;
2502         int i;
2503
2504         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2505         if (!dev)
2506                 goto out1;
2507
2508         pn = ppp_pernet(net);
2509
2510         ppp = netdev_priv(dev);
2511         ppp->dev = dev;
2512         ppp->mru = PPP_MRU;
2513         init_ppp_file(&ppp->file, INTERFACE);
2514         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2515         for (i = 0; i < NUM_NP; ++i)
2516                 ppp->npmode[i] = NPMODE_PASS;
2517         INIT_LIST_HEAD(&ppp->channels);
2518         spin_lock_init(&ppp->rlock);
2519         spin_lock_init(&ppp->wlock);
2520 #ifdef CONFIG_PPP_MULTILINK
2521         ppp->minseq = -1;
2522         skb_queue_head_init(&ppp->mrq);
2523 #endif /* CONFIG_PPP_MULTILINK */
2524
2525         /*
2526          * drum roll: don't forget to set
2527          * the net device is belong to
2528          */
2529         dev_net_set(dev, net);
2530
2531         ret = -EEXIST;
2532         mutex_lock(&pn->all_ppp_mutex);
2533
2534         if (unit < 0) {
2535                 unit = unit_get(&pn->units_idr, ppp);
2536                 if (unit < 0) {
2537                         *retp = unit;
2538                         goto out2;
2539                 }
2540         } else {
2541                 if (unit_find(&pn->units_idr, unit))
2542                         goto out2; /* unit already exists */
2543                 /*
2544                  * if caller need a specified unit number
2545                  * lets try to satisfy him, otherwise --
2546                  * he should better ask us for new unit number
2547                  *
2548                  * NOTE: yes I know that returning EEXIST it's not
2549                  * fair but at least pppd will ask us to allocate
2550                  * new unit in this case so user is happy :)
2551                  */
2552                 unit = unit_set(&pn->units_idr, ppp, unit);
2553                 if (unit < 0)
2554                         goto out2;
2555         }
2556
2557         /* Initialize the new ppp unit */
2558         ppp->file.index = unit;
2559         sprintf(dev->name, "ppp%d", unit);
2560
2561         ret = register_netdev(dev);
2562         if (ret != 0) {
2563                 unit_put(&pn->units_idr, unit);
2564                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2565                        dev->name, ret);
2566                 goto out2;
2567         }
2568
2569         ppp->ppp_net = net;
2570
2571         atomic_inc(&ppp_unit_count);
2572         mutex_unlock(&pn->all_ppp_mutex);
2573
2574         *retp = 0;
2575         return ppp;
2576
2577 out2:
2578         mutex_unlock(&pn->all_ppp_mutex);
2579         free_netdev(dev);
2580 out1:
2581         *retp = ret;
2582         return NULL;
2583 }
2584
2585 /*
2586  * Initialize a ppp_file structure.
2587  */
2588 static void
2589 init_ppp_file(struct ppp_file *pf, int kind)
2590 {
2591         pf->kind = kind;
2592         skb_queue_head_init(&pf->xq);
2593         skb_queue_head_init(&pf->rq);
2594         atomic_set(&pf->refcnt, 1);
2595         init_waitqueue_head(&pf->rwait);
2596 }
2597
2598 /*
2599  * Take down a ppp interface unit - called when the owning file
2600  * (the one that created the unit) is closed or detached.
2601  */
2602 static void ppp_shutdown_interface(struct ppp *ppp)
2603 {
2604         struct ppp_net *pn;
2605
2606         pn = ppp_pernet(ppp->ppp_net);
2607         mutex_lock(&pn->all_ppp_mutex);
2608
2609         /* This will call dev_close() for us. */
2610         ppp_lock(ppp);
2611         if (!ppp->closing) {
2612                 ppp->closing = 1;
2613                 ppp_unlock(ppp);
2614                 unregister_netdev(ppp->dev);
2615         } else
2616                 ppp_unlock(ppp);
2617
2618         unit_put(&pn->units_idr, ppp->file.index);
2619         ppp->file.dead = 1;
2620         ppp->owner = NULL;
2621         wake_up_interruptible(&ppp->file.rwait);
2622
2623         mutex_unlock(&pn->all_ppp_mutex);
2624 }
2625
2626 /*
2627  * Free the memory used by a ppp unit.  This is only called once
2628  * there are no channels connected to the unit and no file structs
2629  * that reference the unit.
2630  */
2631 static void ppp_destroy_interface(struct ppp *ppp)
2632 {
2633         atomic_dec(&ppp_unit_count);
2634
2635         if (!ppp->file.dead || ppp->n_channels) {
2636                 /* "can't happen" */
2637                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2638                        "n_channels=%d !\n", ppp, ppp->file.dead,
2639                        ppp->n_channels);
2640                 return;
2641         }
2642
2643         ppp_ccp_closed(ppp);
2644         if (ppp->vj) {
2645                 slhc_free(ppp->vj);
2646                 ppp->vj = NULL;
2647         }
2648         skb_queue_purge(&ppp->file.xq);
2649         skb_queue_purge(&ppp->file.rq);
2650 #ifdef CONFIG_PPP_MULTILINK
2651         skb_queue_purge(&ppp->mrq);
2652 #endif /* CONFIG_PPP_MULTILINK */
2653 #ifdef CONFIG_PPP_FILTER
2654         kfree(ppp->pass_filter);
2655         ppp->pass_filter = NULL;
2656         kfree(ppp->active_filter);
2657         ppp->active_filter = NULL;
2658 #endif /* CONFIG_PPP_FILTER */
2659
2660         kfree_skb(ppp->xmit_pending);
2661
2662         free_netdev(ppp->dev);
2663 }
2664
2665 /*
2666  * Locate an existing ppp unit.
2667  * The caller should have locked the all_ppp_mutex.
2668  */
2669 static struct ppp *
2670 ppp_find_unit(struct ppp_net *pn, int unit)
2671 {
2672         return unit_find(&pn->units_idr, unit);
2673 }
2674
2675 /*
2676  * Locate an existing ppp channel.
2677  * The caller should have locked the all_channels_lock.
2678  * First we look in the new_channels list, then in the
2679  * all_channels list.  If found in the new_channels list,
2680  * we move it to the all_channels list.  This is for speed
2681  * when we have a lot of channels in use.
2682  */
2683 static struct channel *
2684 ppp_find_channel(struct ppp_net *pn, int unit)
2685 {
2686         struct channel *pch;
2687
2688         list_for_each_entry(pch, &pn->new_channels, list) {
2689                 if (pch->file.index == unit) {
2690                         list_move(&pch->list, &pn->all_channels);
2691                         return pch;
2692                 }
2693         }
2694
2695         list_for_each_entry(pch, &pn->all_channels, list) {
2696                 if (pch->file.index == unit)
2697                         return pch;
2698         }
2699
2700         return NULL;
2701 }
2702
2703 /*
2704  * Connect a PPP channel to a PPP interface unit.
2705  */
2706 static int
2707 ppp_connect_channel(struct channel *pch, int unit)
2708 {
2709         struct ppp *ppp;
2710         struct ppp_net *pn;
2711         int ret = -ENXIO;
2712         int hdrlen;
2713
2714         pn = ppp_pernet(pch->chan_net);
2715
2716         mutex_lock(&pn->all_ppp_mutex);
2717         ppp = ppp_find_unit(pn, unit);
2718         if (!ppp)
2719                 goto out;
2720         write_lock_bh(&pch->upl);
2721         ret = -EINVAL;
2722         if (pch->ppp)
2723                 goto outl;
2724
2725         ppp_lock(ppp);
2726         if (pch->file.hdrlen > ppp->file.hdrlen)
2727                 ppp->file.hdrlen = pch->file.hdrlen;
2728         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2729         if (hdrlen > ppp->dev->hard_header_len)
2730                 ppp->dev->hard_header_len = hdrlen;
2731         list_add_tail(&pch->clist, &ppp->channels);
2732         ++ppp->n_channels;
2733         pch->ppp = ppp;
2734         atomic_inc(&ppp->file.refcnt);
2735         ppp_unlock(ppp);
2736         ret = 0;
2737
2738  outl:
2739         write_unlock_bh(&pch->upl);
2740  out:
2741         mutex_unlock(&pn->all_ppp_mutex);
2742         return ret;
2743 }
2744
2745 /*
2746  * Disconnect a channel from its ppp unit.
2747  */
2748 static int
2749 ppp_disconnect_channel(struct channel *pch)
2750 {
2751         struct ppp *ppp;
2752         int err = -EINVAL;
2753
2754         write_lock_bh(&pch->upl);
2755         ppp = pch->ppp;
2756         pch->ppp = NULL;
2757         write_unlock_bh(&pch->upl);
2758         if (ppp) {
2759                 /* remove it from the ppp unit's list */
2760                 ppp_lock(ppp);
2761                 list_del(&pch->clist);
2762                 if (--ppp->n_channels == 0)
2763                         wake_up_interruptible(&ppp->file.rwait);
2764                 ppp_unlock(ppp);
2765                 if (atomic_dec_and_test(&ppp->file.refcnt))
2766                         ppp_destroy_interface(ppp);
2767                 err = 0;
2768         }
2769         return err;
2770 }
2771
2772 /*
2773  * Free up the resources used by a ppp channel.
2774  */
2775 static void ppp_destroy_channel(struct channel *pch)
2776 {
2777         atomic_dec(&channel_count);
2778
2779         if (!pch->file.dead) {
2780                 /* "can't happen" */
2781                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2782                        pch);
2783                 return;
2784         }
2785         skb_queue_purge(&pch->file.xq);
2786         skb_queue_purge(&pch->file.rq);
2787         kfree(pch);
2788 }
2789
2790 static void __exit ppp_cleanup(void)
2791 {
2792         /* should never happen */
2793         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2794                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2795         unregister_chrdev(PPP_MAJOR, "ppp");
2796         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2797         class_destroy(ppp_class);
2798         unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
2799 }
2800
2801 /*
2802  * Units handling. Caller must protect concurrent access
2803  * by holding all_ppp_mutex
2804  */
2805
2806 /* associate pointer with specified number */
2807 static int unit_set(struct idr *p, void *ptr, int n)
2808 {
2809         int unit, err;
2810
2811 again:
2812         if (!idr_pre_get(p, GFP_KERNEL)) {
2813                 printk(KERN_ERR "PPP: No free memory for idr\n");
2814                 return -ENOMEM;
2815         }
2816
2817         err = idr_get_new_above(p, ptr, n, &unit);
2818         if (err == -EAGAIN)
2819                 goto again;
2820
2821         if (unit != n) {
2822                 idr_remove(p, unit);
2823                 return -EINVAL;
2824         }
2825
2826         return unit;
2827 }
2828
2829 /* get new free unit number and associate pointer with it */
2830 static int unit_get(struct idr *p, void *ptr)
2831 {
2832         int unit, err;
2833
2834 again:
2835         if (!idr_pre_get(p, GFP_KERNEL)) {
2836                 printk(KERN_ERR "PPP: No free memory for idr\n");
2837                 return -ENOMEM;
2838         }
2839
2840         err = idr_get_new_above(p, ptr, 0, &unit);
2841         if (err == -EAGAIN)
2842                 goto again;
2843
2844         return unit;
2845 }
2846
2847 /* put unit number back to a pool */
2848 static void unit_put(struct idr *p, int n)
2849 {
2850         idr_remove(p, n);
2851 }
2852
2853 /* get pointer associated with the number */
2854 static void *unit_find(struct idr *p, int n)
2855 {
2856         return idr_find(p, n);
2857 }
2858
2859 /* Module/initialization stuff */
2860
2861 module_init(ppp_init);
2862 module_exit(ppp_cleanup);
2863
2864 EXPORT_SYMBOL(ppp_register_net_channel);
2865 EXPORT_SYMBOL(ppp_register_channel);
2866 EXPORT_SYMBOL(ppp_unregister_channel);
2867 EXPORT_SYMBOL(ppp_channel_index);
2868 EXPORT_SYMBOL(ppp_unit_number);
2869 EXPORT_SYMBOL(ppp_input);
2870 EXPORT_SYMBOL(ppp_input_error);
2871 EXPORT_SYMBOL(ppp_output_wakeup);
2872 EXPORT_SYMBOL(ppp_register_compressor);
2873 EXPORT_SYMBOL(ppp_unregister_compressor);
2874 MODULE_LICENSE("GPL");
2875 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2876 MODULE_ALIAS("/dev/ppp");