drivers/net/ppp/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/ppp-ioctl.h>
  36 #include <linux/ppp_channel.h>
  37 #include <linux/ppp-comp.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/rtnetlink.h>
  40 #include <linux/if_arp.h>
  41 #include <linux/ip.h>
  42 #include <linux/tcp.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/rwsem.h>
  45 #include <linux/stddef.h>
  46 #include <linux/device.h>
  47 #include <linux/mutex.h>
  48 #include <linux/slab.h>
  49 #include <asm/unaligned.h>
  50 #include <net/slhc_vj.h>
  51 #include <linux/atomic.h>
  52
  53 #include <linux/nsproxy.h>
  54 #include <net/net_namespace.h>
  55 #include <net/netns/generic.h>
  56
  57 #define PPP_VERSION     "2.4.2"
  58
  59 /*
  60  * Network protocols we support.
  61  */
  62 #define NP_IP   0               /* Internet Protocol V4 */
  63 #define NP_IPV6 1               /* Internet Protocol V6 */
  64 #define NP_IPX  2               /* IPX protocol */
  65 #define NP_AT   3               /* Appletalk protocol */
  66 #define NP_MPLS_UC 4            /* MPLS unicast */
  67 #define NP_MPLS_MC 5            /* MPLS multicast */
  68 #define NUM_NP  6               /* Number of NPs. */
  69
  70 #define MPHDRLEN        6       /* multilink protocol header length */
  71 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
  72
  73 /*
  74  * An instance of /dev/ppp can be associated with either a ppp
  75  * interface unit or a ppp channel.  In both cases, file->private_data
  76  * points to one of these.
  77  */
  78 struct ppp_file {
  79         enum {
  80                 INTERFACE=1, CHANNEL
  81         }               kind;
  82         struct sk_buff_head xq;         /* pppd transmit queue */
  83         struct sk_buff_head rq;         /* receive queue for pppd */
  84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
  85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
  86         int             hdrlen;         /* space to leave for headers */
  87         int             index;          /* interface unit / channel number */
  88         int             dead;           /* unit/channel has been shut down */
  89 };
  90
  91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
  92
  93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
  94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
  95
  96 /*
  97  * Data structure to hold primary network stats for which
  98  * we want to use 64 bit storage.  Other network stats
  99  * are stored in dev->stats of the ppp strucute.
 100  */
 101 struct ppp_link_stats {
 102         u64 rx_packets;
 103         u64 tx_packets;
 104         u64 rx_bytes;
 105         u64 tx_bytes;
 106 };
 107
 108 /*
 109  * Data structure describing one ppp unit.
 110  * A ppp unit corresponds to a ppp network interface device
 111  * and represents a multilink bundle.
 112  * It can have 0 or more ppp channels connected to it.
 113  */
 114 struct ppp {
 115         struct ppp_file file;           /* stuff for read/write/poll 0 */
 116         struct file     *owner;         /* file that owns this unit 48 */
 117         struct list_head channels;      /* list of attached channels 4c */
 118         int             n_channels;     /* how many channels are attached 54 */
 119         spinlock_t      rlock;          /* lock for receive side 58 */
 120         spinlock_t      wlock;          /* lock for transmit side 5c */
 121         int             mru;            /* max receive unit 60 */
 122         unsigned int    flags;          /* control bits 64 */
 123         unsigned int    xstate;         /* transmit state bits 68 */
 124         unsigned int    rstate;         /* receive state bits 6c */
 125         int             debug;          /* debug flags 70 */
 126         struct slcompress *vj;          /* state for VJ header compression */
 127         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
 128         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
 129         struct compressor *xcomp;       /* transmit packet compressor 8c */
 130         void            *xc_state;      /* its internal state 90 */
 131         struct compressor *rcomp;       /* receive decompressor 94 */
 132         void            *rc_state;      /* its internal state 98 */
 133         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
 134         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
 135         struct net_device *dev;         /* network interface device a4 */
 136         int             closing;        /* is device closing down? a8 */
 137 #ifdef CONFIG_PPP_MULTILINK
 138         int             nxchan;         /* next channel to send something on */
 139         u32             nxseq;          /* next sequence number to send */
 140         int             mrru;           /* MP: max reconst. receive unit */
 141         u32             nextseq;        /* MP: seq no of next packet */
 142         u32             minseq;         /* MP: min of most recent seqnos */
 143         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
 144 #endif /* CONFIG_PPP_MULTILINK */
 145 #ifdef CONFIG_PPP_FILTER
 146         struct sock_filter *pass_filter;        /* filter for packets to pass */
 147         struct sock_filter *active_filter;/* filter for pkts to reset idle */
 148         unsigned pass_len, active_len;
 149 #endif /* CONFIG_PPP_FILTER */
 150         struct net      *ppp_net;       /* the net we belong to */
 151         struct ppp_link_stats stats64;  /* 64 bit network stats */
 152 };
 153
 154 /*
 155  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
 156  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
 157  * SC_MUST_COMP
 158  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
 159  * Bits in xstate: SC_COMP_RUN
 160  */
 161 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
 162                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
 163                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
 164
 165 /*
 166  * Private data structure for each channel.
 167  * This includes the data structure used for multilink.
 168  */
 169 struct channel {
 170         struct ppp_file file;           /* stuff for read/write/poll */
 171         struct list_head list;          /* link in all/new_channels list */
 172         struct ppp_channel *chan;       /* public channel data structure */
 173         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
 174         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
 175         struct ppp      *ppp;           /* ppp unit we're connected to */
 176         struct net      *chan_net;      /* the net channel belongs to */
 177         struct list_head clist;         /* link in list of channels per unit */
 178         rwlock_t        upl;            /* protects `ppp' */
 179 #ifdef CONFIG_PPP_MULTILINK
 180         u8              avail;          /* flag used in multilink stuff */
 181         u8              had_frag;       /* >= 1 fragments have been sent */
 182         u32             lastseq;        /* MP: last sequence # received */
 183         int             speed;          /* speed of the corresponding ppp channel*/
 184 #endif /* CONFIG_PPP_MULTILINK */
 185 };
 186
 187 /*
 188  * SMP locking issues:
 189  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
 190  * list and the ppp.n_channels field, you need to take both locks
 191  * before you modify them.
 192  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
 193  * channel.downl.
 194  */
 195
 196 static DEFINE_MUTEX(ppp_mutex);
 197 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
 198 static atomic_t channel_count = ATOMIC_INIT(0);
 199
 200 /* per-net private data for this module */
 201 static int ppp_net_id __read_mostly;
 202 struct ppp_net {
 203         /* units to ppp mapping */
 204         struct idr units_idr;
 205
 206         /*
 207          * all_ppp_mutex protects the units_idr mapping.
 208          * It also ensures that finding a ppp unit in the units_idr
 209          * map and updating its file.refcnt field is atomic.
 210          */
 211         struct mutex all_ppp_mutex;
 212
 213         /* channels */
 214         struct list_head all_channels;
 215         struct list_head new_channels;
 216         int last_channel_index;
 217
 218         /*
 219          * all_channels_lock protects all_channels and
 220          * last_channel_index, and the atomicity of find
 221          * a channel and updating its file.refcnt field.
 222          */
 223         spinlock_t all_channels_lock;
 224 };
 225
 226 /* Get the PPP protocol number from a skb */
 227 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
 228
 229 /* We limit the length of ppp->file.rq to this (arbitrary) value */
 230 #define PPP_MAX_RQLEN   32
 231
 232 /*
 233  * Maximum number of multilink fragments queued up.
 234  * This has to be large enough to cope with the maximum latency of
 235  * the slowest channel relative to the others.  Strictly it should
 236  * depend on the number of channels and their characteristics.
 237  */
 238 #define PPP_MP_MAX_QLEN 128
 239
 240 /* Multilink header bits. */
 241 #define B       0x80            /* this fragment begins a packet */
 242 #define E       0x40            /* this fragment ends a packet */
 243
 244 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
 245 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
 246 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 247
 248 /* Prototypes. */
 249 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 250                         struct file *file, unsigned int cmd, unsigned long arg);
 251 static void ppp_xmit_process(struct ppp *ppp);
 252 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 253 static void ppp_push(struct ppp *ppp);
 254 static void ppp_channel_push(struct channel *pch);
 255 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 256                               struct channel *pch);
 257 static void ppp_receive_error(struct ppp *ppp);
 258 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
 259 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
 260                                             struct sk_buff *skb);
 261 #ifdef CONFIG_PPP_MULTILINK
 262 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
 263                                 struct channel *pch);
 264 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 265 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 266 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 267 #endif /* CONFIG_PPP_MULTILINK */
 268 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
 269 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 270 static void ppp_ccp_closed(struct ppp *ppp);
 271 static struct compressor *find_compressor(int type);
 272 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
 273 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 274 static void init_ppp_file(struct ppp_file *pf, int kind);
 275 static void ppp_shutdown_interface(struct ppp *ppp);
 276 static void ppp_destroy_interface(struct ppp *ppp);
 277 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
 278 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 279 static int ppp_connect_channel(struct channel *pch, int unit);
 280 static int ppp_disconnect_channel(struct channel *pch);
 281 static void ppp_destroy_channel(struct channel *pch);
 282 static int unit_get(struct idr *p, void *ptr);
 283 static int unit_set(struct idr *p, void *ptr, int n);
 284 static void unit_put(struct idr *p, int n);
 285 static void *unit_find(struct idr *p, int n);
 286
 287 static struct class *ppp_class;
 288
 289 /* per net-namespace data */
 290 static inline struct ppp_net *ppp_pernet(struct net *net)
 291 {
 292         BUG_ON(!net);
 293
 294         return net_generic(net, ppp_net_id);
 295 }
 296
 297 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 298 static inline int proto_to_npindex(int proto)
 299 {
 300         switch (proto) {
 301         case PPP_IP:
 302                 return NP_IP;
 303         case PPP_IPV6:
 304                 return NP_IPV6;
 305         case PPP_IPX:
 306                 return NP_IPX;
 307         case PPP_AT:
 308                 return NP_AT;
 309         case PPP_MPLS_UC:
 310                 return NP_MPLS_UC;
 311         case PPP_MPLS_MC:
 312                 return NP_MPLS_MC;
 313         }
 314         return -EINVAL;
 315 }
 316
 317 /* Translates an NP index into a PPP protocol number */
 318 static const int npindex_to_proto[NUM_NP] = {
 319         PPP_IP,
 320         PPP_IPV6,
 321         PPP_IPX,
 322         PPP_AT,
 323         PPP_MPLS_UC,
 324         PPP_MPLS_MC,
 325 };
 326
 327 /* Translates an ethertype into an NP index */
 328 static inline int ethertype_to_npindex(int ethertype)
 329 {
 330         switch (ethertype) {
 331         case ETH_P_IP:
 332                 return NP_IP;
 333         case ETH_P_IPV6:
 334                 return NP_IPV6;
 335         case ETH_P_IPX:
 336                 return NP_IPX;
 337         case ETH_P_PPPTALK:
 338         case ETH_P_ATALK:
 339                 return NP_AT;
 340         case ETH_P_MPLS_UC:
 341                 return NP_MPLS_UC;
 342         case ETH_P_MPLS_MC:
 343                 return NP_MPLS_MC;
 344         }
 345         return -1;
 346 }
 347
 348 /* Translates an NP index into an ethertype */
 349 static const int npindex_to_ethertype[NUM_NP] = {
 350         ETH_P_IP,
 351         ETH_P_IPV6,
 352         ETH_P_IPX,
 353         ETH_P_PPPTALK,
 354         ETH_P_MPLS_UC,
 355         ETH_P_MPLS_MC,
 356 };
 357
 358 /*
 359  * Locking shorthand.
 360  */
 361 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
 362 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
 363 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
 364 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
 365 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
 366                                      ppp_recv_lock(ppp); } while (0)
 367 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
 368                                      ppp_xmit_unlock(ppp); } while (0)
 369
 370 /*
 371  * /dev/ppp device routines.
 372  * The /dev/ppp device is used by pppd to control the ppp unit.
 373  * It supports the read, write, ioctl and poll functions.
 374  * Open instances of /dev/ppp can be in one of three states:
 375  * unattached, attached to a ppp unit, or attached to a ppp channel.
 376  */
 377 static int ppp_open(struct inode *inode, struct file *file)
 378 {
 379         /*
 380          * This could (should?) be enforced by the permissions on /dev/ppp.
 381          */
 382         if (!capable(CAP_NET_ADMIN))
 383                 return -EPERM;
 384         return 0;
 385 }
 386
 387 static int ppp_release(struct inode *unused, struct file *file)
 388 {
 389         struct ppp_file *pf = file->private_data;
 390         struct ppp *ppp;
 391
 392         if (pf) {
 393                 file->private_data = NULL;
 394                 if (pf->kind == INTERFACE) {
 395                         ppp = PF_TO_PPP(pf);
 396                         if (file == ppp->owner)
 397                                 ppp_shutdown_interface(ppp);
 398                 }
 399                 if (atomic_dec_and_test(&pf->refcnt)) {
 400                         switch (pf->kind) {
 401                         case INTERFACE:
 402                                 ppp_destroy_interface(PF_TO_PPP(pf));
 403                                 break;
 404                         case CHANNEL:
 405                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
 406                                 break;
 407                         }
 408                 }
 409         }
 410         return 0;
 411 }
 412
 413 static ssize_t ppp_read(struct file *file, char __user *buf,
 414                         size_t count, loff_t *ppos)
 415 {
 416         struct ppp_file *pf = file->private_data;
 417         DECLARE_WAITQUEUE(wait, current);
 418         ssize_t ret;
 419         struct sk_buff *skb = NULL;
 420         struct iovec iov;
 421
 422         ret = count;
 423
 424         if (!pf)
 425                 return -ENXIO;
 426         add_wait_queue(&pf->rwait, &wait);
 427         for (;;) {
 428                 set_current_state(TASK_INTERRUPTIBLE);
 429                 skb = skb_dequeue(&pf->rq);
 430                 if (skb)
 431                         break;
 432                 ret = 0;
 433                 if (pf->dead)
 434                         break;
 435                 if (pf->kind == INTERFACE) {
 436                         /*
 437                          * Return 0 (EOF) on an interface that has no
 438                          * channels connected, unless it is looping
 439                          * network traffic (demand mode).
 440                          */
 441                         struct ppp *ppp = PF_TO_PPP(pf);
 442                         if (ppp->n_channels == 0 &&
 443                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 444                                 break;
 445                 }
 446                 ret = -EAGAIN;
 447                 if (file->f_flags & O_NONBLOCK)
 448                         break;
 449                 ret = -ERESTARTSYS;
 450                 if (signal_pending(current))
 451                         break;
 452                 schedule();
 453         }
 454         set_current_state(TASK_RUNNING);
 455         remove_wait_queue(&pf->rwait, &wait);
 456
 457         if (!skb)
 458                 goto out;
 459
 460         ret = -EOVERFLOW;
 461         if (skb->len > count)
 462                 goto outf;
 463         ret = -EFAULT;
 464         iov.iov_base = buf;
 465         iov.iov_len = count;
 466         if (skb_copy_datagram_iovec(skb, 0, &iov, skb->len))
 467                 goto outf;
 468         ret = skb->len;
 469
 470  outf:
 471         kfree_skb(skb);
 472  out:
 473         return ret;
 474 }
 475
 476 static ssize_t ppp_write(struct file *file, const char __user *buf,
 477                          size_t count, loff_t *ppos)
 478 {
 479         struct ppp_file *pf = file->private_data;
 480         struct sk_buff *skb;
 481         ssize_t ret;
 482
 483         if (!pf)
 484                 return -ENXIO;
 485         ret = -ENOMEM;
 486         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 487         if (!skb)
 488                 goto out;
 489         skb_reserve(skb, pf->hdrlen);
 490         ret = -EFAULT;
 491         if (copy_from_user(skb_put(skb, count), buf, count)) {
 492                 kfree_skb(skb);
 493                 goto out;
 494         }
 495
 496         skb_queue_tail(&pf->xq, skb);
 497
 498         switch (pf->kind) {
 499         case INTERFACE:
 500                 ppp_xmit_process(PF_TO_PPP(pf));
 501                 break;
 502         case CHANNEL:
 503                 ppp_channel_push(PF_TO_CHANNEL(pf));
 504                 break;
 505         }
 506
 507         ret = count;
 508
 509  out:
 510         return ret;
 511 }
 512
 513 /* No kernel lock - fine */
 514 static unsigned int ppp_poll(struct file *file, poll_table *wait)
 515 {
 516         struct ppp_file *pf = file->private_data;
 517         unsigned int mask;
 518
 519         if (!pf)
 520                 return 0;
 521         poll_wait(file, &pf->rwait, wait);
 522         mask = POLLOUT | POLLWRNORM;
 523         if (skb_peek(&pf->rq))
 524                 mask |= POLLIN | POLLRDNORM;
 525         if (pf->dead)
 526                 mask |= POLLHUP;
 527         else if (pf->kind == INTERFACE) {
 528                 /* see comment in ppp_read */
 529                 struct ppp *ppp = PF_TO_PPP(pf);
 530                 if (ppp->n_channels == 0 &&
 531                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
 532                         mask |= POLLIN | POLLRDNORM;
 533         }
 534
 535         return mask;
 536 }
 537
 538 #ifdef CONFIG_PPP_FILTER
 539 static int get_filter(void __user *arg, struct sock_filter **p)
 540 {
 541         struct sock_fprog uprog;
 542         struct sock_filter *code = NULL;
 543         int len, err;
 544
 545         if (copy_from_user(&uprog, arg, sizeof(uprog)))
 546                 return -EFAULT;
 547
 548         if (!uprog.len) {
 549                 *p = NULL;
 550                 return 0;
 551         }
 552
 553         len = uprog.len * sizeof(struct sock_filter);
 554         code = memdup_user(uprog.filter, len);
 555         if (IS_ERR(code))
 556                 return PTR_ERR(code);
 557
 558         err = sk_chk_filter(code, uprog.len);
 559         if (err) {
 560                 kfree(code);
 561                 return err;
 562         }
 563
 564         *p = code;
 565         return uprog.len;
 566 }
 567 #endif /* CONFIG_PPP_FILTER */
 568
 569 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 570 {
 571         struct ppp_file *pf = file->private_data;
 572         struct ppp *ppp;
 573         int err = -EFAULT, val, val2, i;
 574         struct ppp_idle idle;
 575         struct npioctl npi;
 576         int unit, cflags;
 577         struct slcompress *vj;
 578         void __user *argp = (void __user *)arg;
 579         int __user *p = argp;
 580
 581         if (!pf)
 582                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
 583                                         pf, file, cmd, arg);
 584
 585         if (cmd == PPPIOCDETACH) {
 586                 /*
 587                  * We have to be careful here... if the file descriptor
 588                  * has been dup'd, we could have another process in the
 589                  * middle of a poll using the same file *, so we had
 590                  * better not free the interface data structures -
 591                  * instead we fail the ioctl.  Even in this case, we
 592                  * shut down the interface if we are the owner of it.
 593                  * Actually, we should get rid of PPPIOCDETACH, userland
 594                  * (i.e. pppd) could achieve the same effect by closing
 595                  * this fd and reopening /dev/ppp.
 596                  */
 597                 err = -EINVAL;
 598                 mutex_lock(&ppp_mutex);
 599                 if (pf->kind == INTERFACE) {
 600                         ppp = PF_TO_PPP(pf);
 601                         if (file == ppp->owner)
 602                                 ppp_shutdown_interface(ppp);
 603                 }
 604                 if (atomic_long_read(&file->f_count) <= 2) {
 605                         ppp_release(NULL, file);
 606                         err = 0;
 607                 } else
 608                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
 609                                 atomic_long_read(&file->f_count));
 610                 mutex_unlock(&ppp_mutex);
 611                 return err;
 612         }
 613
 614         if (pf->kind == CHANNEL) {
 615                 struct channel *pch;
 616                 struct ppp_channel *chan;
 617
 618                 mutex_lock(&ppp_mutex);
 619                 pch = PF_TO_CHANNEL(pf);
 620
 621                 switch (cmd) {
 622                 case PPPIOCCONNECT:
 623                         if (get_user(unit, p))
 624                                 break;
 625                         err = ppp_connect_channel(pch, unit);
 626                         break;
 627
 628                 case PPPIOCDISCONN:
 629                         err = ppp_disconnect_channel(pch);
 630                         break;
 631
 632                 default:
 633                         down_read(&pch->chan_sem);
 634                         chan = pch->chan;
 635                         err = -ENOTTY;
 636                         if (chan && chan->ops->ioctl)
 637                                 err = chan->ops->ioctl(chan, cmd, arg);
 638                         up_read(&pch->chan_sem);
 639                 }
 640                 mutex_unlock(&ppp_mutex);
 641                 return err;
 642         }
 643
 644         if (pf->kind != INTERFACE) {
 645                 /* can't happen */
 646                 pr_err("PPP: not interface or channel??\n");
 647                 return -EINVAL;
 648         }
 649
 650         mutex_lock(&ppp_mutex);
 651         ppp = PF_TO_PPP(pf);
 652         switch (cmd) {
 653         case PPPIOCSMRU:
 654                 if (get_user(val, p))
 655                         break;
 656                 ppp->mru = val;
 657                 err = 0;
 658                 break;
 659
 660         case PPPIOCSFLAGS:
 661                 if (get_user(val, p))
 662                         break;
 663                 ppp_lock(ppp);
 664                 cflags = ppp->flags & ~val;
 665                 ppp->flags = val & SC_FLAG_BITS;
 666                 ppp_unlock(ppp);
 667                 if (cflags & SC_CCP_OPEN)
 668                         ppp_ccp_closed(ppp);
 669                 err = 0;
 670                 break;
 671
 672         case PPPIOCGFLAGS:
 673                 val = ppp->flags | ppp->xstate | ppp->rstate;
 674                 if (put_user(val, p))
 675                         break;
 676                 err = 0;
 677                 break;
 678
 679         case PPPIOCSCOMPRESS:
 680                 err = ppp_set_compress(ppp, arg);
 681                 break;
 682
 683         case PPPIOCGUNIT:
 684                 if (put_user(ppp->file.index, p))
 685                         break;
 686                 err = 0;
 687                 break;
 688
 689         case PPPIOCSDEBUG:
 690                 if (get_user(val, p))
 691                         break;
 692                 ppp->debug = val;
 693                 err = 0;
 694                 break;
 695
 696         case PPPIOCGDEBUG:
 697                 if (put_user(ppp->debug, p))
 698                         break;
 699                 err = 0;
 700                 break;
 701
 702         case PPPIOCGIDLE:
 703                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
 704                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
 705                 if (copy_to_user(argp, &idle, sizeof(idle)))
 706                         break;
 707                 err = 0;
 708                 break;
 709
 710         case PPPIOCSMAXCID:
 711                 if (get_user(val, p))
 712                         break;
 713                 val2 = 15;
 714                 if ((val >> 16) != 0) {
 715                         val2 = val >> 16;
 716                         val &= 0xffff;
 717                 }
 718                 vj = slhc_init(val2+1, val+1);
 719                 if (!vj) {
 720                         netdev_err(ppp->dev,
 721                                    "PPP: no memory (VJ compressor)\n");
 722                         err = -ENOMEM;
 723                         break;
 724                 }
 725                 ppp_lock(ppp);
 726                 if (ppp->vj)
 727                         slhc_free(ppp->vj);
 728                 ppp->vj = vj;
 729                 ppp_unlock(ppp);
 730                 err = 0;
 731                 break;
 732
 733         case PPPIOCGNPMODE:
 734         case PPPIOCSNPMODE:
 735                 if (copy_from_user(&npi, argp, sizeof(npi)))
 736                         break;
 737                 err = proto_to_npindex(npi.protocol);
 738                 if (err < 0)
 739                         break;
 740                 i = err;
 741                 if (cmd == PPPIOCGNPMODE) {
 742                         err = -EFAULT;
 743                         npi.mode = ppp->npmode[i];
 744                         if (copy_to_user(argp, &npi, sizeof(npi)))
 745                                 break;
 746                 } else {
 747                         ppp->npmode[i] = npi.mode;
 748                         /* we may be able to transmit more packets now (??) */
 749                         netif_wake_queue(ppp->dev);
 750                 }
 751                 err = 0;
 752                 break;
 753
 754 #ifdef CONFIG_PPP_FILTER
 755         case PPPIOCSPASS:
 756         {
 757                 struct sock_filter *code;
 758                 err = get_filter(argp, &code);
 759                 if (err >= 0) {
 760                         ppp_lock(ppp);
 761                         kfree(ppp->pass_filter);
 762                         ppp->pass_filter = code;
 763                         ppp->pass_len = err;
 764                         ppp_unlock(ppp);
 765                         err = 0;
 766                 }
 767                 break;
 768         }
 769         case PPPIOCSACTIVE:
 770         {
 771                 struct sock_filter *code;
 772                 err = get_filter(argp, &code);
 773                 if (err >= 0) {
 774                         ppp_lock(ppp);
 775                         kfree(ppp->active_filter);
 776                         ppp->active_filter = code;
 777                         ppp->active_len = err;
 778                         ppp_unlock(ppp);
 779                         err = 0;
 780                 }
 781                 break;
 782         }
 783 #endif /* CONFIG_PPP_FILTER */
 784
 785 #ifdef CONFIG_PPP_MULTILINK
 786         case PPPIOCSMRRU:
 787                 if (get_user(val, p))
 788                         break;
 789                 ppp_recv_lock(ppp);
 790                 ppp->mrru = val;
 791                 ppp_recv_unlock(ppp);
 792                 err = 0;
 793                 break;
 794 #endif /* CONFIG_PPP_MULTILINK */
 795
 796         default:
 797                 err = -ENOTTY;
 798         }
 799         mutex_unlock(&ppp_mutex);
 800         return err;
 801 }
 802
 803 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 804                         struct file *file, unsigned int cmd, unsigned long arg)
 805 {
 806         int unit, err = -EFAULT;
 807         struct ppp *ppp;
 808         struct channel *chan;
 809         struct ppp_net *pn;
 810         int __user *p = (int __user *)arg;
 811
 812         mutex_lock(&ppp_mutex);
 813         switch (cmd) {
 814         case PPPIOCNEWUNIT:
 815                 /* Create a new ppp unit */
 816                 if (get_user(unit, p))
 817                         break;
 818                 ppp = ppp_create_interface(net, unit, &err);
 819                 if (!ppp)
 820                         break;
 821                 file->private_data = &ppp->file;
 822                 ppp->owner = file;
 823                 err = -EFAULT;
 824                 if (put_user(ppp->file.index, p))
 825                         break;
 826                 err = 0;
 827                 break;
 828
 829         case PPPIOCATTACH:
 830                 /* Attach to an existing ppp unit */
 831                 if (get_user(unit, p))
 832                         break;
 833                 err = -ENXIO;
 834                 pn = ppp_pernet(net);
 835                 mutex_lock(&pn->all_ppp_mutex);
 836                 ppp = ppp_find_unit(pn, unit);
 837                 if (ppp) {
 838                         atomic_inc(&ppp->file.refcnt);
 839                         file->private_data = &ppp->file;
 840                         err = 0;
 841                 }
 842                 mutex_unlock(&pn->all_ppp_mutex);
 843                 break;
 844
 845         case PPPIOCATTCHAN:
 846                 if (get_user(unit, p))
 847                         break;
 848                 err = -ENXIO;
 849                 pn = ppp_pernet(net);
 850                 spin_lock_bh(&pn->all_channels_lock);
 851                 chan = ppp_find_channel(pn, unit);
 852                 if (chan) {
 853                         atomic_inc(&chan->file.refcnt);
 854                         file->private_data = &chan->file;
 855                         err = 0;
 856                 }
 857                 spin_unlock_bh(&pn->all_channels_lock);
 858                 break;
 859
 860         default:
 861                 err = -ENOTTY;
 862         }
 863         mutex_unlock(&ppp_mutex);
 864         return err;
 865 }
 866
 867 static const struct file_operations ppp_device_fops = {
 868         .owner          = THIS_MODULE,
 869         .read           = ppp_read,
 870         .write          = ppp_write,
 871         .poll           = ppp_poll,
 872         .unlocked_ioctl = ppp_ioctl,
 873         .open           = ppp_open,
 874         .release        = ppp_release,
 875         .llseek         = noop_llseek,
 876 };
 877
 878 static __net_init int ppp_init_net(struct net *net)
 879 {
 880         struct ppp_net *pn = net_generic(net, ppp_net_id);
 881
 882         idr_init(&pn->units_idr);
 883         mutex_init(&pn->all_ppp_mutex);
 884
 885         INIT_LIST_HEAD(&pn->all_channels);
 886         INIT_LIST_HEAD(&pn->new_channels);
 887
 888         spin_lock_init(&pn->all_channels_lock);
 889
 890         return 0;
 891 }
 892
 893 static __net_exit void ppp_exit_net(struct net *net)
 894 {
 895         struct ppp_net *pn = net_generic(net, ppp_net_id);
 896
 897         idr_destroy(&pn->units_idr);
 898 }
 899
 900 static struct pernet_operations ppp_net_ops = {
 901         .init = ppp_init_net,
 902         .exit = ppp_exit_net,
 903         .id   = &ppp_net_id,
 904         .size = sizeof(struct ppp_net),
 905 };
 906
 907 #define PPP_MAJOR       108
 908
 909 /* Called at boot time if ppp is compiled into the kernel,
 910    or at module load time (from init_module) if compiled as a module. */
 911 static int __init ppp_init(void)
 912 {
 913         int err;
 914
 915         pr_info("PPP generic driver version " PPP_VERSION "\n");
 916
 917         err = register_pernet_device(&ppp_net_ops);
 918         if (err) {
 919                 pr_err("failed to register PPP pernet device (%d)\n", err);
 920                 goto out;
 921         }
 922
 923         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
 924         if (err) {
 925                 pr_err("failed to register PPP device (%d)\n", err);
 926                 goto out_net;
 927         }
 928
 929         ppp_class = class_create(THIS_MODULE, "ppp");
 930         if (IS_ERR(ppp_class)) {
 931                 err = PTR_ERR(ppp_class);
 932                 goto out_chrdev;
 933         }
 934
 935         /* not a big deal if we fail here :-) */
 936         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 937
 938         return 0;
 939
 940 out_chrdev:
 941         unregister_chrdev(PPP_MAJOR, "ppp");
 942 out_net:
 943         unregister_pernet_device(&ppp_net_ops);
 944 out:
 945         return err;
 946 }
 947
 948 /*
 949  * Network interface unit routines.
 950  */
 951 static netdev_tx_t
 952 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 953 {
 954         struct ppp *ppp = netdev_priv(dev);
 955         int npi, proto;
 956         unsigned char *pp;
 957
 958         npi = ethertype_to_npindex(ntohs(skb->protocol));
 959         if (npi < 0)
 960                 goto outf;
 961
 962         /* Drop, accept or reject the packet */
 963         switch (ppp->npmode[npi]) {
 964         case NPMODE_PASS:
 965                 break;
 966         case NPMODE_QUEUE:
 967                 /* it would be nice to have a way to tell the network
 968                    system to queue this one up for later. */
 969                 goto outf;
 970         case NPMODE_DROP:
 971         case NPMODE_ERROR:
 972                 goto outf;
 973         }
 974
 975         /* Put the 2-byte PPP protocol number on the front,
 976            making sure there is room for the address and control fields. */
 977         if (skb_cow_head(skb, PPP_HDRLEN))
 978                 goto outf;
 979
 980         pp = skb_push(skb, 2);
 981         proto = npindex_to_proto[npi];
 982         put_unaligned_be16(proto, pp);
 983
 984         skb_queue_tail(&ppp->file.xq, skb);
 985         ppp_xmit_process(ppp);
 986         return NETDEV_TX_OK;
 987
 988  outf:
 989         kfree_skb(skb);
 990         ++dev->stats.tx_dropped;
 991         return NETDEV_TX_OK;
 992 }
 993
 994 static int
 995 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 996 {
 997         struct ppp *ppp = netdev_priv(dev);
 998         int err = -EFAULT;
 999         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1000         struct ppp_stats stats;
1001         struct ppp_comp_stats cstats;
1002         char *vers;
1003
1004         switch (cmd) {
1005         case SIOCGPPPSTATS:
1006                 ppp_get_stats(ppp, &stats);
1007                 if (copy_to_user(addr, &stats, sizeof(stats)))
1008                         break;
1009                 err = 0;
1010                 break;
1011
1012         case SIOCGPPPCSTATS:
1013                 memset(&cstats, 0, sizeof(cstats));
1014                 if (ppp->xc_state)
1015                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1016                 if (ppp->rc_state)
1017                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1018                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1019                         break;
1020                 err = 0;
1021                 break;
1022
1023         case SIOCGPPPVER:
1024                 vers = PPP_VERSION;
1025                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1026                         break;
1027                 err = 0;
1028                 break;
1029
1030         default:
1031                 err = -EINVAL;
1032         }
1033
1034         return err;
1035 }
1036
1037 static struct rtnl_link_stats64*
1038 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1039 {
1040         struct ppp *ppp = netdev_priv(dev);
1041
1042         ppp_recv_lock(ppp);
1043         stats64->rx_packets = ppp->stats64.rx_packets;
1044         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1045         ppp_recv_unlock(ppp);
1046
1047         ppp_xmit_lock(ppp);
1048         stats64->tx_packets = ppp->stats64.tx_packets;
1049         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1050         ppp_xmit_unlock(ppp);
1051
1052         stats64->rx_errors        = dev->stats.rx_errors;
1053         stats64->tx_errors        = dev->stats.tx_errors;
1054         stats64->rx_dropped       = dev->stats.rx_dropped;
1055         stats64->tx_dropped       = dev->stats.tx_dropped;
1056         stats64->rx_length_errors = dev->stats.rx_length_errors;
1057
1058         return stats64;
1059 }
1060
1061 static struct lock_class_key ppp_tx_busylock;
1062 static int ppp_dev_init(struct net_device *dev)
1063 {
1064         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1065         return 0;
1066 }
1067
1068 static const struct net_device_ops ppp_netdev_ops = {
1069         .ndo_init        = ppp_dev_init,
1070         .ndo_start_xmit  = ppp_start_xmit,
1071         .ndo_do_ioctl    = ppp_net_ioctl,
1072         .ndo_get_stats64 = ppp_get_stats64,
1073 };
1074
1075 static void ppp_setup(struct net_device *dev)
1076 {
1077         dev->netdev_ops = &ppp_netdev_ops;
1078         dev->hard_header_len = PPP_HDRLEN;
1079         dev->mtu = PPP_MRU;
1080         dev->addr_len = 0;
1081         dev->tx_queue_len = 3;
1082         dev->type = ARPHRD_PPP;
1083         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1084         dev->features |= NETIF_F_NETNS_LOCAL;
1085         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1086 }
1087
1088 /*
1089  * Transmit-side routines.
1090  */
1091
1092 /*
1093  * Called to do any work queued up on the transmit side
1094  * that can now be done.
1095  */
1096 static void
1097 ppp_xmit_process(struct ppp *ppp)
1098 {
1099         struct sk_buff *skb;
1100
1101         ppp_xmit_lock(ppp);
1102         if (!ppp->closing) {
1103                 ppp_push(ppp);
1104                 while (!ppp->xmit_pending &&
1105                        (skb = skb_dequeue(&ppp->file.xq)))
1106                         ppp_send_frame(ppp, skb);
1107                 /* If there's no work left to do, tell the core net
1108                    code that we can accept some more. */
1109                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1110                         netif_wake_queue(ppp->dev);
1111                 else
1112                         netif_stop_queue(ppp->dev);
1113         }
1114         ppp_xmit_unlock(ppp);
1115 }
1116
1117 static inline struct sk_buff *
1118 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1119 {
1120         struct sk_buff *new_skb;
1121         int len;
1122         int new_skb_size = ppp->dev->mtu +
1123                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1124         int compressor_skb_size = ppp->dev->mtu +
1125                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1126         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1127         if (!new_skb) {
1128                 if (net_ratelimit())
1129                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1130                 return NULL;
1131         }
1132         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1133                 skb_reserve(new_skb,
1134                             ppp->dev->hard_header_len - PPP_HDRLEN);
1135
1136         /* compressor still expects A/C bytes in hdr */
1137         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1138                                    new_skb->data, skb->len + 2,
1139                                    compressor_skb_size);
1140         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1141                 consume_skb(skb);
1142                 skb = new_skb;
1143                 skb_put(skb, len);
1144                 skb_pull(skb, 2);       /* pull off A/C bytes */
1145         } else if (len == 0) {
1146                 /* didn't compress, or CCP not up yet */
1147                 consume_skb(new_skb);
1148                 new_skb = skb;
1149         } else {
1150                 /*
1151                  * (len < 0)
1152                  * MPPE requires that we do not send unencrypted
1153                  * frames.  The compressor will return -1 if we
1154                  * should drop the frame.  We cannot simply test
1155                  * the compress_proto because MPPE and MPPC share
1156                  * the same number.
1157                  */
1158                 if (net_ratelimit())
1159                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1160                 kfree_skb(skb);
1161                 consume_skb(new_skb);
1162                 new_skb = NULL;
1163         }
1164         return new_skb;
1165 }
1166
1167 /*
1168  * Compress and send a frame.
1169  * The caller should have locked the xmit path,
1170  * and xmit_pending should be 0.
1171  */
1172 static void
1173 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1174 {
1175         int proto = PPP_PROTO(skb);
1176         struct sk_buff *new_skb;
1177         int len;
1178         unsigned char *cp;
1179
1180         if (proto < 0x8000) {
1181 #ifdef CONFIG_PPP_FILTER
1182                 /* check if we should pass this packet */
1183                 /* the filter instructions are constructed assuming
1184                    a four-byte PPP header on each packet */
1185                 *skb_push(skb, 2) = 1;
1186                 if (ppp->pass_filter &&
1187                     sk_run_filter(skb, ppp->pass_filter) == 0) {
1188                         if (ppp->debug & 1)
1189                                 netdev_printk(KERN_DEBUG, ppp->dev,
1190                                               "PPP: outbound frame "
1191                                               "not passed\n");
1192                         kfree_skb(skb);
1193                         return;
1194                 }
1195                 /* if this packet passes the active filter, record the time */
1196                 if (!(ppp->active_filter &&
1197                       sk_run_filter(skb, ppp->active_filter) == 0))
1198                         ppp->last_xmit = jiffies;
1199                 skb_pull(skb, 2);
1200 #else
1201                 /* for data packets, record the time */
1202                 ppp->last_xmit = jiffies;
1203 #endif /* CONFIG_PPP_FILTER */
1204         }
1205
1206         ++ppp->stats64.tx_packets;
1207         ppp->stats64.tx_bytes += skb->len - 2;
1208
1209         switch (proto) {
1210         case PPP_IP:
1211                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1212                         break;
1213                 /* try to do VJ TCP header compression */
1214                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1215                                     GFP_ATOMIC);
1216                 if (!new_skb) {
1217                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1218                         goto drop;
1219                 }
1220                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1221                 cp = skb->data + 2;
1222                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1223                                     new_skb->data + 2, &cp,
1224                                     !(ppp->flags & SC_NO_TCP_CCID));
1225                 if (cp == skb->data + 2) {
1226                         /* didn't compress */
1227                         consume_skb(new_skb);
1228                 } else {
1229                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1230                                 proto = PPP_VJC_COMP;
1231                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1232                         } else {
1233                                 proto = PPP_VJC_UNCOMP;
1234                                 cp[0] = skb->data[2];
1235                         }
1236                         consume_skb(skb);
1237                         skb = new_skb;
1238                         cp = skb_put(skb, len + 2);
1239                         cp[0] = 0;
1240                         cp[1] = proto;
1241                 }
1242                 break;
1243
1244         case PPP_CCP:
1245                 /* peek at outbound CCP frames */
1246                 ppp_ccp_peek(ppp, skb, 0);
1247                 break;
1248         }
1249
1250         /* try to do packet compression */
1251         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1252             proto != PPP_LCP && proto != PPP_CCP) {
1253                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1254                         if (net_ratelimit())
1255                                 netdev_err(ppp->dev,
1256                                            "ppp: compression required but "
1257                                            "down - pkt dropped.\n");
1258                         goto drop;
1259                 }
1260                 skb = pad_compress_skb(ppp, skb);
1261                 if (!skb)
1262                         goto drop;
1263         }
1264
1265         /*
1266          * If we are waiting for traffic (demand dialling),
1267          * queue it up for pppd to receive.
1268          */
1269         if (ppp->flags & SC_LOOP_TRAFFIC) {
1270                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1271                         goto drop;
1272                 skb_queue_tail(&ppp->file.rq, skb);
1273                 wake_up_interruptible(&ppp->file.rwait);
1274                 return;
1275         }
1276
1277         ppp->xmit_pending = skb;
1278         ppp_push(ppp);
1279         return;
1280
1281  drop:
1282         kfree_skb(skb);
1283         ++ppp->dev->stats.tx_errors;
1284 }
1285
1286 /*
1287  * Try to send the frame in xmit_pending.
1288  * The caller should have the xmit path locked.
1289  */
1290 static void
1291 ppp_push(struct ppp *ppp)
1292 {
1293         struct list_head *list;
1294         struct channel *pch;
1295         struct sk_buff *skb = ppp->xmit_pending;
1296
1297         if (!skb)
1298                 return;
1299
1300         list = &ppp->channels;
1301         if (list_empty(list)) {
1302                 /* nowhere to send the packet, just drop it */
1303                 ppp->xmit_pending = NULL;
1304                 kfree_skb(skb);
1305                 return;
1306         }
1307
1308         if ((ppp->flags & SC_MULTILINK) == 0) {
1309                 /* not doing multilink: send it down the first channel */
1310                 list = list->next;
1311                 pch = list_entry(list, struct channel, clist);
1312
1313                 spin_lock_bh(&pch->downl);
1314                 if (pch->chan) {
1315                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1316                                 ppp->xmit_pending = NULL;
1317                 } else {
1318                         /* channel got unregistered */
1319                         kfree_skb(skb);
1320                         ppp->xmit_pending = NULL;
1321                 }
1322                 spin_unlock_bh(&pch->downl);
1323                 return;
1324         }
1325
1326 #ifdef CONFIG_PPP_MULTILINK
1327         /* Multilink: fragment the packet over as many links
1328            as can take the packet at the moment. */
1329         if (!ppp_mp_explode(ppp, skb))
1330                 return;
1331 #endif /* CONFIG_PPP_MULTILINK */
1332
1333         ppp->xmit_pending = NULL;
1334         kfree_skb(skb);
1335 }
1336
1337 #ifdef CONFIG_PPP_MULTILINK
1338 static bool mp_protocol_compress __read_mostly = true;
1339 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1340 MODULE_PARM_DESC(mp_protocol_compress,
1341                  "compress protocol id in multilink fragments");
1342
1343 /*
1344  * Divide a packet to be transmitted into fragments and
1345  * send them out the individual links.
1346  */
1347 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1348 {
1349         int len, totlen;
1350         int i, bits, hdrlen, mtu;
1351         int flen;
1352         int navail, nfree, nzero;
1353         int nbigger;
1354         int totspeed;
1355         int totfree;
1356         unsigned char *p, *q;
1357         struct list_head *list;
1358         struct channel *pch;
1359         struct sk_buff *frag;
1360         struct ppp_channel *chan;
1361
1362         totspeed = 0; /*total bitrate of the bundle*/
1363         nfree = 0; /* # channels which have no packet already queued */
1364         navail = 0; /* total # of usable channels (not deregistered) */
1365         nzero = 0; /* number of channels with zero speed associated*/
1366         totfree = 0; /*total # of channels available and
1367                                   *having no queued packets before
1368                                   *starting the fragmentation*/
1369
1370         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1371         i = 0;
1372         list_for_each_entry(pch, &ppp->channels, clist) {
1373                 if (pch->chan) {
1374                         pch->avail = 1;
1375                         navail++;
1376                         pch->speed = pch->chan->speed;
1377                 } else {
1378                         pch->avail = 0;
1379                 }
1380                 if (pch->avail) {
1381                         if (skb_queue_empty(&pch->file.xq) ||
1382                                 !pch->had_frag) {
1383                                         if (pch->speed == 0)
1384                                                 nzero++;
1385                                         else
1386                                                 totspeed += pch->speed;
1387
1388                                         pch->avail = 2;
1389                                         ++nfree;
1390                                         ++totfree;
1391                                 }
1392                         if (!pch->had_frag && i < ppp->nxchan)
1393                                 ppp->nxchan = i;
1394                 }
1395                 ++i;
1396         }
1397         /*
1398          * Don't start sending this packet unless at least half of
1399          * the channels are free.  This gives much better TCP
1400          * performance if we have a lot of channels.
1401          */
1402         if (nfree == 0 || nfree < navail / 2)
1403                 return 0; /* can't take now, leave it in xmit_pending */
1404
1405         /* Do protocol field compression */
1406         p = skb->data;
1407         len = skb->len;
1408         if (*p == 0 && mp_protocol_compress) {
1409                 ++p;
1410                 --len;
1411         }
1412
1413         totlen = len;
1414         nbigger = len % nfree;
1415
1416         /* skip to the channel after the one we last used
1417            and start at that one */
1418         list = &ppp->channels;
1419         for (i = 0; i < ppp->nxchan; ++i) {
1420                 list = list->next;
1421                 if (list == &ppp->channels) {
1422                         i = 0;
1423                         break;
1424                 }
1425         }
1426
1427         /* create a fragment for each channel */
1428         bits = B;
1429         while (len > 0) {
1430                 list = list->next;
1431                 if (list == &ppp->channels) {
1432                         i = 0;
1433                         continue;
1434                 }
1435                 pch = list_entry(list, struct channel, clist);
1436                 ++i;
1437                 if (!pch->avail)
1438                         continue;
1439
1440                 /*
1441                  * Skip this channel if it has a fragment pending already and
1442                  * we haven't given a fragment to all of the free channels.
1443                  */
1444                 if (pch->avail == 1) {
1445                         if (nfree > 0)
1446                                 continue;
1447                 } else {
1448                         pch->avail = 1;
1449                 }
1450
1451                 /* check the channel's mtu and whether it is still attached. */
1452                 spin_lock_bh(&pch->downl);
1453                 if (pch->chan == NULL) {
1454                         /* can't use this channel, it's being deregistered */
1455                         if (pch->speed == 0)
1456                                 nzero--;
1457                         else
1458                                 totspeed -= pch->speed;
1459
1460                         spin_unlock_bh(&pch->downl);
1461                         pch->avail = 0;
1462                         totlen = len;
1463                         totfree--;
1464                         nfree--;
1465                         if (--navail == 0)
1466                                 break;
1467                         continue;
1468                 }
1469
1470                 /*
1471                 *if the channel speed is not set divide
1472                 *the packet evenly among the free channels;
1473                 *otherwise divide it according to the speed
1474                 *of the channel we are going to transmit on
1475                 */
1476                 flen = len;
1477                 if (nfree > 0) {
1478                         if (pch->speed == 0) {
1479                                 flen = len/nfree;
1480                                 if (nbigger > 0) {
1481                                         flen++;
1482                                         nbigger--;
1483                                 }
1484                         } else {
1485                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1486                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1487                                 if (nbigger > 0) {
1488                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1489                                         nbigger -= ((totfree - nzero)*pch->speed)/
1490                                                         totspeed;
1491                                 }
1492                         }
1493                         nfree--;
1494                 }
1495
1496                 /*
1497                  *check if we are on the last channel or
1498                  *we exceded the length of the data to
1499                  *fragment
1500                  */
1501                 if ((nfree <= 0) || (flen > len))
1502                         flen = len;
1503                 /*
1504                  *it is not worth to tx on slow channels:
1505                  *in that case from the resulting flen according to the
1506                  *above formula will be equal or less than zero.
1507                  *Skip the channel in this case
1508                  */
1509                 if (flen <= 0) {
1510                         pch->avail = 2;
1511                         spin_unlock_bh(&pch->downl);
1512                         continue;
1513                 }
1514
1515                 /*
1516                  * hdrlen includes the 2-byte PPP protocol field, but the
1517                  * MTU counts only the payload excluding the protocol field.
1518                  * (RFC1661 Section 2)
1519                  */
1520                 mtu = pch->chan->mtu - (hdrlen - 2);
1521                 if (mtu < 4)
1522                         mtu = 4;
1523                 if (flen > mtu)
1524                         flen = mtu;
1525                 if (flen == len)
1526                         bits |= E;
1527                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1528                 if (!frag)
1529                         goto noskb;
1530                 q = skb_put(frag, flen + hdrlen);
1531
1532                 /* make the MP header */
1533                 put_unaligned_be16(PPP_MP, q);
1534                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1535                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1536                         q[3] = ppp->nxseq;
1537                 } else {
1538                         q[2] = bits;
1539                         q[3] = ppp->nxseq >> 16;
1540                         q[4] = ppp->nxseq >> 8;
1541                         q[5] = ppp->nxseq;
1542                 }
1543
1544                 memcpy(q + hdrlen, p, flen);
1545
1546                 /* try to send it down the channel */
1547                 chan = pch->chan;
1548                 if (!skb_queue_empty(&pch->file.xq) ||
1549                         !chan->ops->start_xmit(chan, frag))
1550                         skb_queue_tail(&pch->file.xq, frag);
1551                 pch->had_frag = 1;
1552                 p += flen;
1553                 len -= flen;
1554                 ++ppp->nxseq;
1555                 bits = 0;
1556                 spin_unlock_bh(&pch->downl);
1557         }
1558         ppp->nxchan = i;
1559
1560         return 1;
1561
1562  noskb:
1563         spin_unlock_bh(&pch->downl);
1564         if (ppp->debug & 1)
1565                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1566         ++ppp->dev->stats.tx_errors;
1567         ++ppp->nxseq;
1568         return 1;       /* abandon the frame */
1569 }
1570 #endif /* CONFIG_PPP_MULTILINK */
1571
1572 /*
1573  * Try to send data out on a channel.
1574  */
1575 static void
1576 ppp_channel_push(struct channel *pch)
1577 {
1578         struct sk_buff *skb;
1579         struct ppp *ppp;
1580
1581         spin_lock_bh(&pch->downl);
1582         if (pch->chan) {
1583                 while (!skb_queue_empty(&pch->file.xq)) {
1584                         skb = skb_dequeue(&pch->file.xq);
1585                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1586                                 /* put the packet back and try again later */
1587                                 skb_queue_head(&pch->file.xq, skb);
1588                                 break;
1589                         }
1590                 }
1591         } else {
1592                 /* channel got deregistered */
1593                 skb_queue_purge(&pch->file.xq);
1594         }
1595         spin_unlock_bh(&pch->downl);
1596         /* see if there is anything from the attached unit to be sent */
1597         if (skb_queue_empty(&pch->file.xq)) {
1598                 read_lock_bh(&pch->upl);
1599                 ppp = pch->ppp;
1600                 if (ppp)
1601                         ppp_xmit_process(ppp);
1602                 read_unlock_bh(&pch->upl);
1603         }
1604 }
1605
1606 /*
1607  * Receive-side routines.
1608  */
1609
1610 struct ppp_mp_skb_parm {
1611         u32             sequence;
1612         u8              BEbits;
1613 };
1614 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1615
1616 static inline void
1617 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1618 {
1619         ppp_recv_lock(ppp);
1620         if (!ppp->closing)
1621                 ppp_receive_frame(ppp, skb, pch);
1622         else
1623                 kfree_skb(skb);
1624         ppp_recv_unlock(ppp);
1625 }
1626
1627 void
1628 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1629 {
1630         struct channel *pch = chan->ppp;
1631         int proto;
1632
1633         if (!pch) {
1634                 kfree_skb(skb);
1635                 return;
1636         }
1637
1638         read_lock_bh(&pch->upl);
1639         if (!pskb_may_pull(skb, 2)) {
1640                 kfree_skb(skb);
1641                 if (pch->ppp) {
1642                         ++pch->ppp->dev->stats.rx_length_errors;
1643                         ppp_receive_error(pch->ppp);
1644                 }
1645                 goto done;
1646         }
1647
1648         proto = PPP_PROTO(skb);
1649         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1650                 /* put it on the channel queue */
1651                 skb_queue_tail(&pch->file.rq, skb);
1652                 /* drop old frames if queue too long */
1653                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1654                        (skb = skb_dequeue(&pch->file.rq)))
1655                         kfree_skb(skb);
1656                 wake_up_interruptible(&pch->file.rwait);
1657         } else {
1658                 ppp_do_recv(pch->ppp, skb, pch);
1659         }
1660
1661 done:
1662         read_unlock_bh(&pch->upl);
1663 }
1664
1665 /* Put a 0-length skb in the receive queue as an error indication */
1666 void
1667 ppp_input_error(struct ppp_channel *chan, int code)
1668 {
1669         struct channel *pch = chan->ppp;
1670         struct sk_buff *skb;
1671
1672         if (!pch)
1673                 return;
1674
1675         read_lock_bh(&pch->upl);
1676         if (pch->ppp) {
1677                 skb = alloc_skb(0, GFP_ATOMIC);
1678                 if (skb) {
1679                         skb->len = 0;           /* probably unnecessary */
1680                         skb->cb[0] = code;
1681                         ppp_do_recv(pch->ppp, skb, pch);
1682                 }
1683         }
1684         read_unlock_bh(&pch->upl);
1685 }
1686
1687 /*
1688  * We come in here to process a received frame.
1689  * The receive side of the ppp unit is locked.
1690  */
1691 static void
1692 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1693 {
1694         /* note: a 0-length skb is used as an error indication */
1695         if (skb->len > 0) {
1696 #ifdef CONFIG_PPP_MULTILINK
1697                 /* XXX do channel-level decompression here */
1698                 if (PPP_PROTO(skb) == PPP_MP)
1699                         ppp_receive_mp_frame(ppp, skb, pch);
1700                 else
1701 #endif /* CONFIG_PPP_MULTILINK */
1702                         ppp_receive_nonmp_frame(ppp, skb);
1703         } else {
1704                 kfree_skb(skb);
1705                 ppp_receive_error(ppp);
1706         }
1707 }
1708
1709 static void
1710 ppp_receive_error(struct ppp *ppp)
1711 {
1712         ++ppp->dev->stats.rx_errors;
1713         if (ppp->vj)
1714                 slhc_toss(ppp->vj);
1715 }
1716
1717 static void
1718 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1719 {
1720         struct sk_buff *ns;
1721         int proto, len, npi;
1722
1723         /*
1724          * Decompress the frame, if compressed.
1725          * Note that some decompressors need to see uncompressed frames
1726          * that come in as well as compressed frames.
1727          */
1728         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1729             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1730                 skb = ppp_decompress_frame(ppp, skb);
1731
1732         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1733                 goto err;
1734
1735         proto = PPP_PROTO(skb);
1736         switch (proto) {
1737         case PPP_VJC_COMP:
1738                 /* decompress VJ compressed packets */
1739                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1740                         goto err;
1741
1742                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1743                         /* copy to a new sk_buff with more tailroom */
1744                         ns = dev_alloc_skb(skb->len + 128);
1745                         if (!ns) {
1746                                 netdev_err(ppp->dev, "PPP: no memory "
1747                                            "(VJ decomp)\n");
1748                                 goto err;
1749                         }
1750                         skb_reserve(ns, 2);
1751                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1752                         consume_skb(skb);
1753                         skb = ns;
1754                 }
1755                 else
1756                         skb->ip_summed = CHECKSUM_NONE;
1757
1758                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1759                 if (len <= 0) {
1760                         netdev_printk(KERN_DEBUG, ppp->dev,
1761                                       "PPP: VJ decompression error\n");
1762                         goto err;
1763                 }
1764                 len += 2;
1765                 if (len > skb->len)
1766                         skb_put(skb, len - skb->len);
1767                 else if (len < skb->len)
1768                         skb_trim(skb, len);
1769                 proto = PPP_IP;
1770                 break;
1771
1772         case PPP_VJC_UNCOMP:
1773                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1774                         goto err;
1775
1776                 /* Until we fix the decompressor need to make sure
1777                  * data portion is linear.
1778                  */
1779                 if (!pskb_may_pull(skb, skb->len))
1780                         goto err;
1781
1782                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1783                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1784                         goto err;
1785                 }
1786                 proto = PPP_IP;
1787                 break;
1788
1789         case PPP_CCP:
1790                 ppp_ccp_peek(ppp, skb, 1);
1791                 break;
1792         }
1793
1794         ++ppp->stats64.rx_packets;
1795         ppp->stats64.rx_bytes += skb->len - 2;
1796
1797         npi = proto_to_npindex(proto);
1798         if (npi < 0) {
1799                 /* control or unknown frame - pass it to pppd */
1800                 skb_queue_tail(&ppp->file.rq, skb);
1801                 /* limit queue length by dropping old frames */
1802                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1803                        (skb = skb_dequeue(&ppp->file.rq)))
1804                         kfree_skb(skb);
1805                 /* wake up any process polling or blocking on read */
1806                 wake_up_interruptible(&ppp->file.rwait);
1807
1808         } else {
1809                 /* network protocol frame - give it to the kernel */
1810
1811 #ifdef CONFIG_PPP_FILTER
1812                 /* check if the packet passes the pass and active filters */
1813                 /* the filter instructions are constructed assuming
1814                    a four-byte PPP header on each packet */
1815                 if (ppp->pass_filter || ppp->active_filter) {
1816                         if (skb_unclone(skb, GFP_ATOMIC))
1817                                 goto err;
1818
1819                         *skb_push(skb, 2) = 0;
1820                         if (ppp->pass_filter &&
1821                             sk_run_filter(skb, ppp->pass_filter) == 0) {
1822                                 if (ppp->debug & 1)
1823                                         netdev_printk(KERN_DEBUG, ppp->dev,
1824                                                       "PPP: inbound frame "
1825                                                       "not passed\n");
1826                                 kfree_skb(skb);
1827                                 return;
1828                         }
1829                         if (!(ppp->active_filter &&
1830                               sk_run_filter(skb, ppp->active_filter) == 0))
1831                                 ppp->last_recv = jiffies;
1832                         __skb_pull(skb, 2);
1833                 } else
1834 #endif /* CONFIG_PPP_FILTER */
1835                         ppp->last_recv = jiffies;
1836
1837                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1838                     ppp->npmode[npi] != NPMODE_PASS) {
1839                         kfree_skb(skb);
1840                 } else {
1841                         /* chop off protocol */
1842                         skb_pull_rcsum(skb, 2);
1843                         skb->dev = ppp->dev;
1844                         skb->protocol = htons(npindex_to_ethertype[npi]);
1845                         skb_reset_mac_header(skb);
1846                         netif_rx(skb);
1847                 }
1848         }
1849         return;
1850
1851  err:
1852         kfree_skb(skb);
1853         ppp_receive_error(ppp);
1854 }
1855
1856 static struct sk_buff *
1857 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1858 {
1859         int proto = PPP_PROTO(skb);
1860         struct sk_buff *ns;
1861         int len;
1862
1863         /* Until we fix all the decompressor's need to make sure
1864          * data portion is linear.
1865          */
1866         if (!pskb_may_pull(skb, skb->len))
1867                 goto err;
1868
1869         if (proto == PPP_COMP) {
1870                 int obuff_size;
1871
1872                 switch(ppp->rcomp->compress_proto) {
1873                 case CI_MPPE:
1874                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1875                         break;
1876                 default:
1877                         obuff_size = ppp->mru + PPP_HDRLEN;
1878                         break;
1879                 }
1880
1881                 ns = dev_alloc_skb(obuff_size);
1882                 if (!ns) {
1883                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1884                                    "no memory\n");
1885                         goto err;
1886                 }
1887                 /* the decompressor still expects the A/C bytes in the hdr */
1888                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1889                                 skb->len + 2, ns->data, obuff_size);
1890                 if (len < 0) {
1891                         /* Pass the compressed frame to pppd as an
1892                            error indication. */
1893                         if (len == DECOMP_FATALERROR)
1894                                 ppp->rstate |= SC_DC_FERROR;
1895                         kfree_skb(ns);
1896                         goto err;
1897                 }
1898
1899                 consume_skb(skb);
1900                 skb = ns;
1901                 skb_put(skb, len);
1902                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1903
1904         } else {
1905                 /* Uncompressed frame - pass to decompressor so it
1906                    can update its dictionary if necessary. */
1907                 if (ppp->rcomp->incomp)
1908                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1909                                            skb->len + 2);
1910         }
1911
1912         return skb;
1913
1914  err:
1915         ppp->rstate |= SC_DC_ERROR;
1916         ppp_receive_error(ppp);
1917         return skb;
1918 }
1919
1920 #ifdef CONFIG_PPP_MULTILINK
1921 /*
1922  * Receive a multilink frame.
1923  * We put it on the reconstruction queue and then pull off
1924  * as many completed frames as we can.
1925  */
1926 static void
1927 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1928 {
1929         u32 mask, seq;
1930         struct channel *ch;
1931         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1932
1933         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1934                 goto err;               /* no good, throw it away */
1935
1936         /* Decode sequence number and begin/end bits */
1937         if (ppp->flags & SC_MP_SHORTSEQ) {
1938                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1939                 mask = 0xfff;
1940         } else {
1941                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1942                 mask = 0xffffff;
1943         }
1944         PPP_MP_CB(skb)->BEbits = skb->data[2];
1945         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1946
1947         /*
1948          * Do protocol ID decompression on the first fragment of each packet.
1949          */
1950         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
1951                 *skb_push(skb, 1) = 0;
1952
1953         /*
1954          * Expand sequence number to 32 bits, making it as close
1955          * as possible to ppp->minseq.
1956          */
1957         seq |= ppp->minseq & ~mask;
1958         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1959                 seq += mask + 1;
1960         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1961                 seq -= mask + 1;        /* should never happen */
1962         PPP_MP_CB(skb)->sequence = seq;
1963         pch->lastseq = seq;
1964
1965         /*
1966          * If this packet comes before the next one we were expecting,
1967          * drop it.
1968          */
1969         if (seq_before(seq, ppp->nextseq)) {
1970                 kfree_skb(skb);
1971                 ++ppp->dev->stats.rx_dropped;
1972                 ppp_receive_error(ppp);
1973                 return;
1974         }
1975
1976         /*
1977          * Reevaluate minseq, the minimum over all channels of the
1978          * last sequence number received on each channel.  Because of
1979          * the increasing sequence number rule, we know that any fragment
1980          * before `minseq' which hasn't arrived is never going to arrive.
1981          * The list of channels can't change because we have the receive
1982          * side of the ppp unit locked.
1983          */
1984         list_for_each_entry(ch, &ppp->channels, clist) {
1985                 if (seq_before(ch->lastseq, seq))
1986                         seq = ch->lastseq;
1987         }
1988         if (seq_before(ppp->minseq, seq))
1989                 ppp->minseq = seq;
1990
1991         /* Put the fragment on the reconstruction queue */
1992         ppp_mp_insert(ppp, skb);
1993
1994         /* If the queue is getting long, don't wait any longer for packets
1995            before the start of the queue. */
1996         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1997                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
1998                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
1999                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2000         }
2001
2002         /* Pull completed packets off the queue and receive them. */
2003         while ((skb = ppp_mp_reconstruct(ppp))) {
2004                 if (pskb_may_pull(skb, 2))
2005                         ppp_receive_nonmp_frame(ppp, skb);
2006                 else {
2007                         ++ppp->dev->stats.rx_length_errors;
2008                         kfree_skb(skb);
2009                         ppp_receive_error(ppp);
2010                 }
2011         }
2012
2013         return;
2014
2015  err:
2016         kfree_skb(skb);
2017         ppp_receive_error(ppp);
2018 }
2019
2020 /*
2021  * Insert a fragment on the MP reconstruction queue.
2022  * The queue is ordered by increasing sequence number.
2023  */
2024 static void
2025 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2026 {
2027         struct sk_buff *p;
2028         struct sk_buff_head *list = &ppp->mrq;
2029         u32 seq = PPP_MP_CB(skb)->sequence;
2030
2031         /* N.B. we don't need to lock the list lock because we have the
2032            ppp unit receive-side lock. */
2033         skb_queue_walk(list, p) {
2034                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2035                         break;
2036         }
2037         __skb_queue_before(list, p, skb);
2038 }
2039
2040 /*
2041  * Reconstruct a packet from the MP fragment queue.
2042  * We go through increasing sequence numbers until we find a
2043  * complete packet, or we get to the sequence number for a fragment
2044  * which hasn't arrived but might still do so.
2045  */
2046 static struct sk_buff *
2047 ppp_mp_reconstruct(struct ppp *ppp)
2048 {
2049         u32 seq = ppp->nextseq;
2050         u32 minseq = ppp->minseq;
2051         struct sk_buff_head *list = &ppp->mrq;
2052         struct sk_buff *p, *tmp;
2053         struct sk_buff *head, *tail;
2054         struct sk_buff *skb = NULL;
2055         int lost = 0, len = 0;
2056
2057         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2058                 return NULL;
2059         head = list->next;
2060         tail = NULL;
2061         skb_queue_walk_safe(list, p, tmp) {
2062         again:
2063                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2064                         /* this can't happen, anyway ignore the skb */
2065                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2066                                    "seq %u < %u\n",
2067                                    PPP_MP_CB(p)->sequence, seq);
2068                         __skb_unlink(p, list);
2069                         kfree_skb(p);
2070                         continue;
2071                 }
2072                 if (PPP_MP_CB(p)->sequence != seq) {
2073                         u32 oldseq;
2074                         /* Fragment `seq' is missing.  If it is after
2075                            minseq, it might arrive later, so stop here. */
2076                         if (seq_after(seq, minseq))
2077                                 break;
2078                         /* Fragment `seq' is lost, keep going. */
2079                         lost = 1;
2080                         oldseq = seq;
2081                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2082                                 minseq + 1: PPP_MP_CB(p)->sequence;
2083
2084                         if (ppp->debug & 1)
2085                                 netdev_printk(KERN_DEBUG, ppp->dev,
2086                                               "lost frag %u..%u\n",
2087                                               oldseq, seq-1);
2088
2089                         goto again;
2090                 }
2091
2092                 /*
2093                  * At this point we know that all the fragments from
2094                  * ppp->nextseq to seq are either present or lost.
2095                  * Also, there are no complete packets in the queue
2096                  * that have no missing fragments and end before this
2097                  * fragment.
2098                  */
2099
2100                 /* B bit set indicates this fragment starts a packet */
2101                 if (PPP_MP_CB(p)->BEbits & B) {
2102                         head = p;
2103                         lost = 0;
2104                         len = 0;
2105                 }
2106
2107                 len += p->len;
2108
2109                 /* Got a complete packet yet? */
2110                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2111                     (PPP_MP_CB(head)->BEbits & B)) {
2112                         if (len > ppp->mrru + 2) {
2113                                 ++ppp->dev->stats.rx_length_errors;
2114                                 netdev_printk(KERN_DEBUG, ppp->dev,
2115                                               "PPP: reconstructed packet"
2116                                               " is too long (%d)\n", len);
2117                         } else {
2118                                 tail = p;
2119                                 break;
2120                         }
2121                         ppp->nextseq = seq + 1;
2122                 }
2123
2124                 /*
2125                  * If this is the ending fragment of a packet,
2126                  * and we haven't found a complete valid packet yet,
2127                  * we can discard up to and including this fragment.
2128                  */
2129                 if (PPP_MP_CB(p)->BEbits & E) {
2130                         struct sk_buff *tmp2;
2131
2132                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2133                                 if (ppp->debug & 1)
2134                                         netdev_printk(KERN_DEBUG, ppp->dev,
2135                                                       "discarding frag %u\n",
2136                                                       PPP_MP_CB(p)->sequence);
2137                                 __skb_unlink(p, list);
2138                                 kfree_skb(p);
2139                         }
2140                         head = skb_peek(list);
2141                         if (!head)
2142                                 break;
2143                 }
2144                 ++seq;
2145         }
2146
2147         /* If we have a complete packet, copy it all into one skb. */
2148         if (tail != NULL) {
2149                 /* If we have discarded any fragments,
2150                    signal a receive error. */
2151                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2152                         skb_queue_walk_safe(list, p, tmp) {
2153                                 if (p == head)
2154                                         break;
2155                                 if (ppp->debug & 1)
2156                                         netdev_printk(KERN_DEBUG, ppp->dev,
2157                                                       "discarding frag %u\n",
2158                                                       PPP_MP_CB(p)->sequence);
2159                                 __skb_unlink(p, list);
2160                                 kfree_skb(p);
2161                         }
2162
2163                         if (ppp->debug & 1)
2164                                 netdev_printk(KERN_DEBUG, ppp->dev,
2165                                               "  missed pkts %u..%u\n",
2166                                               ppp->nextseq,
2167                                               PPP_MP_CB(head)->sequence-1);
2168                         ++ppp->dev->stats.rx_dropped;
2169                         ppp_receive_error(ppp);
2170                 }
2171
2172                 skb = head;
2173                 if (head != tail) {
2174                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2175                         p = skb_queue_next(list, head);
2176                         __skb_unlink(skb, list);
2177                         skb_queue_walk_from_safe(list, p, tmp) {
2178                                 __skb_unlink(p, list);
2179                                 *fragpp = p;
2180                                 p->next = NULL;
2181                                 fragpp = &p->next;
2182
2183                                 skb->len += p->len;
2184                                 skb->data_len += p->len;
2185                                 skb->truesize += p->truesize;
2186
2187                                 if (p == tail)
2188                                         break;
2189                         }
2190                 } else {
2191                         __skb_unlink(skb, list);
2192                 }
2193
2194                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2195         }
2196
2197         return skb;
2198 }
2199 #endif /* CONFIG_PPP_MULTILINK */
2200
2201 /*
2202  * Channel interface.
2203  */
2204
2205 /* Create a new, unattached ppp channel. */
2206 int ppp_register_channel(struct ppp_channel *chan)
2207 {
2208         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2209 }
2210
2211 /* Create a new, unattached ppp channel for specified net. */
2212 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2213 {
2214         struct channel *pch;
2215         struct ppp_net *pn;
2216
2217         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2218         if (!pch)
2219                 return -ENOMEM;
2220
2221         pn = ppp_pernet(net);
2222
2223         pch->ppp = NULL;
2224         pch->chan = chan;
2225         pch->chan_net = net;
2226         chan->ppp = pch;
2227         init_ppp_file(&pch->file, CHANNEL);
2228         pch->file.hdrlen = chan->hdrlen;
2229 #ifdef CONFIG_PPP_MULTILINK
2230         pch->lastseq = -1;
2231 #endif /* CONFIG_PPP_MULTILINK */
2232         init_rwsem(&pch->chan_sem);
2233         spin_lock_init(&pch->downl);
2234         rwlock_init(&pch->upl);
2235
2236         spin_lock_bh(&pn->all_channels_lock);
2237         pch->file.index = ++pn->last_channel_index;
2238         list_add(&pch->list, &pn->new_channels);
2239         atomic_inc(&channel_count);
2240         spin_unlock_bh(&pn->all_channels_lock);
2241
2242         return 0;
2243 }
2244
2245 /*
2246  * Return the index of a channel.
2247  */
2248 int ppp_channel_index(struct ppp_channel *chan)
2249 {
2250         struct channel *pch = chan->ppp;
2251
2252         if (pch)
2253                 return pch->file.index;
2254         return -1;
2255 }
2256
2257 /*
2258  * Return the PPP unit number to which a channel is connected.
2259  */
2260 int ppp_unit_number(struct ppp_channel *chan)
2261 {
2262         struct channel *pch = chan->ppp;
2263         int unit = -1;
2264
2265         if (pch) {
2266                 read_lock_bh(&pch->upl);
2267                 if (pch->ppp)
2268                         unit = pch->ppp->file.index;
2269                 read_unlock_bh(&pch->upl);
2270         }
2271         return unit;
2272 }
2273
2274 /*
2275  * Return the PPP device interface name of a channel.
2276  */
2277 char *ppp_dev_name(struct ppp_channel *chan)
2278 {
2279         struct channel *pch = chan->ppp;
2280         char *name = NULL;
2281
2282         if (pch) {
2283                 read_lock_bh(&pch->upl);
2284                 if (pch->ppp && pch->ppp->dev)
2285                         name = pch->ppp->dev->name;
2286                 read_unlock_bh(&pch->upl);
2287         }
2288         return name;
2289 }
2290
2291
2292 /*
2293  * Disconnect a channel from the generic layer.
2294  * This must be called in process context.
2295  */
2296 void
2297 ppp_unregister_channel(struct ppp_channel *chan)
2298 {
2299         struct channel *pch = chan->ppp;
2300         struct ppp_net *pn;
2301
2302         if (!pch)
2303                 return;         /* should never happen */
2304
2305         chan->ppp = NULL;
2306
2307         /*
2308          * This ensures that we have returned from any calls into the
2309          * the channel's start_xmit or ioctl routine before we proceed.
2310          */
2311         down_write(&pch->chan_sem);
2312         spin_lock_bh(&pch->downl);
2313         pch->chan = NULL;
2314         spin_unlock_bh(&pch->downl);
2315         up_write(&pch->chan_sem);
2316         ppp_disconnect_channel(pch);
2317
2318         pn = ppp_pernet(pch->chan_net);
2319         spin_lock_bh(&pn->all_channels_lock);
2320         list_del(&pch->list);
2321         spin_unlock_bh(&pn->all_channels_lock);
2322
2323         pch->file.dead = 1;
2324         wake_up_interruptible(&pch->file.rwait);
2325         if (atomic_dec_and_test(&pch->file.refcnt))
2326                 ppp_destroy_channel(pch);
2327 }
2328
2329 /*
2330  * Callback from a channel when it can accept more to transmit.
2331  * This should be called at BH/softirq level, not interrupt level.
2332  */
2333 void
2334 ppp_output_wakeup(struct ppp_channel *chan)
2335 {
2336         struct channel *pch = chan->ppp;
2337
2338         if (!pch)
2339                 return;
2340         ppp_channel_push(pch);
2341 }
2342
2343 /*
2344  * Compression control.
2345  */
2346
2347 /* Process the PPPIOCSCOMPRESS ioctl. */
2348 static int
2349 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2350 {
2351         int err;
2352         struct compressor *cp, *ocomp;
2353         struct ppp_option_data data;
2354         void *state, *ostate;
2355         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2356
2357         err = -EFAULT;
2358         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2359             (data.length <= CCP_MAX_OPTION_LENGTH &&
2360              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2361                 goto out;
2362         err = -EINVAL;
2363         if (data.length > CCP_MAX_OPTION_LENGTH ||
2364             ccp_option[1] < 2 || ccp_option[1] > data.length)
2365                 goto out;
2366
2367         cp = try_then_request_module(
2368                 find_compressor(ccp_option[0]),
2369                 "ppp-compress-%d", ccp_option[0]);
2370         if (!cp)
2371                 goto out;
2372
2373         err = -ENOBUFS;
2374         if (data.transmit) {
2375                 state = cp->comp_alloc(ccp_option, data.length);
2376                 if (state) {
2377                         ppp_xmit_lock(ppp);
2378                         ppp->xstate &= ~SC_COMP_RUN;
2379                         ocomp = ppp->xcomp;
2380                         ostate = ppp->xc_state;
2381                         ppp->xcomp = cp;
2382                         ppp->xc_state = state;
2383                         ppp_xmit_unlock(ppp);
2384                         if (ostate) {
2385                                 ocomp->comp_free(ostate);
2386                                 module_put(ocomp->owner);
2387                         }
2388                         err = 0;
2389                 } else
2390                         module_put(cp->owner);
2391
2392         } else {
2393                 state = cp->decomp_alloc(ccp_option, data.length);
2394                 if (state) {
2395                         ppp_recv_lock(ppp);
2396                         ppp->rstate &= ~SC_DECOMP_RUN;
2397                         ocomp = ppp->rcomp;
2398                         ostate = ppp->rc_state;
2399                         ppp->rcomp = cp;
2400                         ppp->rc_state = state;
2401                         ppp_recv_unlock(ppp);
2402                         if (ostate) {
2403                                 ocomp->decomp_free(ostate);
2404                                 module_put(ocomp->owner);
2405                         }
2406                         err = 0;
2407                 } else
2408                         module_put(cp->owner);
2409         }
2410
2411  out:
2412         return err;
2413 }
2414
2415 /*
2416  * Look at a CCP packet and update our state accordingly.
2417  * We assume the caller has the xmit or recv path locked.
2418  */
2419 static void
2420 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2421 {
2422         unsigned char *dp;
2423         int len;
2424
2425         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2426                 return; /* no header */
2427         dp = skb->data + 2;
2428
2429         switch (CCP_CODE(dp)) {
2430         case CCP_CONFREQ:
2431
2432                 /* A ConfReq starts negotiation of compression
2433                  * in one direction of transmission,
2434                  * and hence brings it down...but which way?
2435                  *
2436                  * Remember:
2437                  * A ConfReq indicates what the sender would like to receive
2438                  */
2439                 if(inbound)
2440                         /* He is proposing what I should send */
2441                         ppp->xstate &= ~SC_COMP_RUN;
2442                 else
2443                         /* I am proposing to what he should send */
2444                         ppp->rstate &= ~SC_DECOMP_RUN;
2445
2446                 break;
2447
2448         case CCP_TERMREQ:
2449         case CCP_TERMACK:
2450                 /*
2451                  * CCP is going down, both directions of transmission
2452                  */
2453                 ppp->rstate &= ~SC_DECOMP_RUN;
2454                 ppp->xstate &= ~SC_COMP_RUN;
2455                 break;
2456
2457         case CCP_CONFACK:
2458                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2459                         break;
2460                 len = CCP_LENGTH(dp);
2461                 if (!pskb_may_pull(skb, len + 2))
2462                         return;         /* too short */
2463                 dp += CCP_HDRLEN;
2464                 len -= CCP_HDRLEN;
2465                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2466                         break;
2467                 if (inbound) {
2468                         /* we will start receiving compressed packets */
2469                         if (!ppp->rc_state)
2470                                 break;
2471                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2472                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2473                                 ppp->rstate |= SC_DECOMP_RUN;
2474                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2475                         }
2476                 } else {
2477                         /* we will soon start sending compressed packets */
2478                         if (!ppp->xc_state)
2479                                 break;
2480                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2481                                         ppp->file.index, 0, ppp->debug))
2482                                 ppp->xstate |= SC_COMP_RUN;
2483                 }
2484                 break;
2485
2486         case CCP_RESETACK:
2487                 /* reset the [de]compressor */
2488                 if ((ppp->flags & SC_CCP_UP) == 0)
2489                         break;
2490                 if (inbound) {
2491                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2492                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2493                                 ppp->rstate &= ~SC_DC_ERROR;
2494                         }
2495                 } else {
2496                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2497                                 ppp->xcomp->comp_reset(ppp->xc_state);
2498                 }
2499                 break;
2500         }
2501 }
2502
2503 /* Free up compression resources. */
2504 static void
2505 ppp_ccp_closed(struct ppp *ppp)
2506 {
2507         void *xstate, *rstate;
2508         struct compressor *xcomp, *rcomp;
2509
2510         ppp_lock(ppp);
2511         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2512         ppp->xstate = 0;
2513         xcomp = ppp->xcomp;
2514         xstate = ppp->xc_state;
2515         ppp->xc_state = NULL;
2516         ppp->rstate = 0;
2517         rcomp = ppp->rcomp;
2518         rstate = ppp->rc_state;
2519         ppp->rc_state = NULL;
2520         ppp_unlock(ppp);
2521
2522         if (xstate) {
2523                 xcomp->comp_free(xstate);
2524                 module_put(xcomp->owner);
2525         }
2526         if (rstate) {
2527                 rcomp->decomp_free(rstate);
2528                 module_put(rcomp->owner);
2529         }
2530 }
2531
2532 /* List of compressors. */
2533 static LIST_HEAD(compressor_list);
2534 static DEFINE_SPINLOCK(compressor_list_lock);
2535
2536 struct compressor_entry {
2537         struct list_head list;
2538         struct compressor *comp;
2539 };
2540
2541 static struct compressor_entry *
2542 find_comp_entry(int proto)
2543 {
2544         struct compressor_entry *ce;
2545
2546         list_for_each_entry(ce, &compressor_list, list) {
2547                 if (ce->comp->compress_proto == proto)
2548                         return ce;
2549         }
2550         return NULL;
2551 }
2552
2553 /* Register a compressor */
2554 int
2555 ppp_register_compressor(struct compressor *cp)
2556 {
2557         struct compressor_entry *ce;
2558         int ret;
2559         spin_lock(&compressor_list_lock);
2560         ret = -EEXIST;
2561         if (find_comp_entry(cp->compress_proto))
2562                 goto out;
2563         ret = -ENOMEM;
2564         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2565         if (!ce)
2566                 goto out;
2567         ret = 0;
2568         ce->comp = cp;
2569         list_add(&ce->list, &compressor_list);
2570  out:
2571         spin_unlock(&compressor_list_lock);
2572         return ret;
2573 }
2574
2575 /* Unregister a compressor */
2576 void
2577 ppp_unregister_compressor(struct compressor *cp)
2578 {
2579         struct compressor_entry *ce;
2580
2581         spin_lock(&compressor_list_lock);
2582         ce = find_comp_entry(cp->compress_proto);
2583         if (ce && ce->comp == cp) {
2584                 list_del(&ce->list);
2585                 kfree(ce);
2586         }
2587         spin_unlock(&compressor_list_lock);
2588 }
2589
2590 /* Find a compressor. */
2591 static struct compressor *
2592 find_compressor(int type)
2593 {
2594         struct compressor_entry *ce;
2595         struct compressor *cp = NULL;
2596
2597         spin_lock(&compressor_list_lock);
2598         ce = find_comp_entry(type);
2599         if (ce) {
2600                 cp = ce->comp;
2601                 if (!try_module_get(cp->owner))
2602                         cp = NULL;
2603         }
2604         spin_unlock(&compressor_list_lock);
2605         return cp;
2606 }
2607
2608 /*
2609  * Miscelleneous stuff.
2610  */
2611
2612 static void
2613 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2614 {
2615         struct slcompress *vj = ppp->vj;
2616
2617         memset(st, 0, sizeof(*st));
2618         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2619         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2620         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2621         st->p.ppp_opackets = ppp->stats64.tx_packets;
2622         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2623         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2624         if (!vj)
2625                 return;
2626         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2627         st->vj.vjs_compressed = vj->sls_o_compressed;
2628         st->vj.vjs_searches = vj->sls_o_searches;
2629         st->vj.vjs_misses = vj->sls_o_misses;
2630         st->vj.vjs_errorin = vj->sls_i_error;
2631         st->vj.vjs_tossed = vj->sls_i_tossed;
2632         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2633         st->vj.vjs_compressedin = vj->sls_i_compressed;
2634 }
2635
2636 /*
2637  * Stuff for handling the lists of ppp units and channels
2638  * and for initialization.
2639  */
2640
2641 /*
2642  * Create a new ppp interface unit.  Fails if it can't allocate memory
2643  * or if there is already a unit with the requested number.
2644  * unit == -1 means allocate a new number.
2645  */
2646 static struct ppp *
2647 ppp_create_interface(struct net *net, int unit, int *retp)
2648 {
2649         struct ppp *ppp;
2650         struct ppp_net *pn;
2651         struct net_device *dev = NULL;
2652         int ret = -ENOMEM;
2653         int i;
2654
2655         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2656         if (!dev)
2657                 goto out1;
2658
2659         pn = ppp_pernet(net);
2660
2661         ppp = netdev_priv(dev);
2662         ppp->dev = dev;
2663         ppp->mru = PPP_MRU;
2664         init_ppp_file(&ppp->file, INTERFACE);
2665         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2666         for (i = 0; i < NUM_NP; ++i)
2667                 ppp->npmode[i] = NPMODE_PASS;
2668         INIT_LIST_HEAD(&ppp->channels);
2669         spin_lock_init(&ppp->rlock);
2670         spin_lock_init(&ppp->wlock);
2671 #ifdef CONFIG_PPP_MULTILINK
2672         ppp->minseq = -1;
2673         skb_queue_head_init(&ppp->mrq);
2674 #endif /* CONFIG_PPP_MULTILINK */
2675
2676         /*
2677          * drum roll: don't forget to set
2678          * the net device is belong to
2679          */
2680         dev_net_set(dev, net);
2681
2682         mutex_lock(&pn->all_ppp_mutex);
2683
2684         if (unit < 0) {
2685                 unit = unit_get(&pn->units_idr, ppp);
2686                 if (unit < 0) {
2687                         ret = unit;
2688                         goto out2;
2689                 }
2690         } else {
2691                 ret = -EEXIST;
2692                 if (unit_find(&pn->units_idr, unit))
2693                         goto out2; /* unit already exists */
2694                 /*
2695                  * if caller need a specified unit number
2696                  * lets try to satisfy him, otherwise --
2697                  * he should better ask us for new unit number
2698                  *
2699                  * NOTE: yes I know that returning EEXIST it's not
2700                  * fair but at least pppd will ask us to allocate
2701                  * new unit in this case so user is happy :)
2702                  */
2703                 unit = unit_set(&pn->units_idr, ppp, unit);
2704                 if (unit < 0)
2705                         goto out2;
2706         }
2707
2708         /* Initialize the new ppp unit */
2709         ppp->file.index = unit;
2710         sprintf(dev->name, "ppp%d", unit);
2711
2712         ret = register_netdev(dev);
2713         if (ret != 0) {
2714                 unit_put(&pn->units_idr, unit);
2715                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2716                            dev->name, ret);
2717                 goto out2;
2718         }
2719
2720         ppp->ppp_net = net;
2721
2722         atomic_inc(&ppp_unit_count);
2723         mutex_unlock(&pn->all_ppp_mutex);
2724
2725         *retp = 0;
2726         return ppp;
2727
2728 out2:
2729         mutex_unlock(&pn->all_ppp_mutex);
2730         free_netdev(dev);
2731 out1:
2732         *retp = ret;
2733         return NULL;
2734 }
2735
2736 /*
2737  * Initialize a ppp_file structure.
2738  */
2739 static void
2740 init_ppp_file(struct ppp_file *pf, int kind)
2741 {
2742         pf->kind = kind;
2743         skb_queue_head_init(&pf->xq);
2744         skb_queue_head_init(&pf->rq);
2745         atomic_set(&pf->refcnt, 1);
2746         init_waitqueue_head(&pf->rwait);
2747 }
2748
2749 /*
2750  * Take down a ppp interface unit - called when the owning file
2751  * (the one that created the unit) is closed or detached.
2752  */
2753 static void ppp_shutdown_interface(struct ppp *ppp)
2754 {
2755         struct ppp_net *pn;
2756
2757         pn = ppp_pernet(ppp->ppp_net);
2758         mutex_lock(&pn->all_ppp_mutex);
2759
2760         /* This will call dev_close() for us. */
2761         ppp_lock(ppp);
2762         if (!ppp->closing) {
2763                 ppp->closing = 1;
2764                 ppp_unlock(ppp);
2765                 unregister_netdev(ppp->dev);
2766                 unit_put(&pn->units_idr, ppp->file.index);
2767         } else
2768                 ppp_unlock(ppp);
2769
2770         ppp->file.dead = 1;
2771         ppp->owner = NULL;
2772         wake_up_interruptible(&ppp->file.rwait);
2773
2774         mutex_unlock(&pn->all_ppp_mutex);
2775 }
2776
2777 /*
2778  * Free the memory used by a ppp unit.  This is only called once
2779  * there are no channels connected to the unit and no file structs
2780  * that reference the unit.
2781  */
2782 static void ppp_destroy_interface(struct ppp *ppp)
2783 {
2784         atomic_dec(&ppp_unit_count);
2785
2786         if (!ppp->file.dead || ppp->n_channels) {
2787                 /* "can't happen" */
2788                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2789                            "but dead=%d n_channels=%d !\n",
2790                            ppp, ppp->file.dead, ppp->n_channels);
2791                 return;
2792         }
2793
2794         ppp_ccp_closed(ppp);
2795         if (ppp->vj) {
2796                 slhc_free(ppp->vj);
2797                 ppp->vj = NULL;
2798         }
2799         skb_queue_purge(&ppp->file.xq);
2800         skb_queue_purge(&ppp->file.rq);
2801 #ifdef CONFIG_PPP_MULTILINK
2802         skb_queue_purge(&ppp->mrq);
2803 #endif /* CONFIG_PPP_MULTILINK */
2804 #ifdef CONFIG_PPP_FILTER
2805         kfree(ppp->pass_filter);
2806         ppp->pass_filter = NULL;
2807         kfree(ppp->active_filter);
2808         ppp->active_filter = NULL;
2809 #endif /* CONFIG_PPP_FILTER */
2810
2811         kfree_skb(ppp->xmit_pending);
2812
2813         free_netdev(ppp->dev);
2814 }
2815
2816 /*
2817  * Locate an existing ppp unit.
2818  * The caller should have locked the all_ppp_mutex.
2819  */
2820 static struct ppp *
2821 ppp_find_unit(struct ppp_net *pn, int unit)
2822 {
2823         return unit_find(&pn->units_idr, unit);
2824 }
2825
2826 /*
2827  * Locate an existing ppp channel.
2828  * The caller should have locked the all_channels_lock.
2829  * First we look in the new_channels list, then in the
2830  * all_channels list.  If found in the new_channels list,
2831  * we move it to the all_channels list.  This is for speed
2832  * when we have a lot of channels in use.
2833  */
2834 static struct channel *
2835 ppp_find_channel(struct ppp_net *pn, int unit)
2836 {
2837         struct channel *pch;
2838
2839         list_for_each_entry(pch, &pn->new_channels, list) {
2840                 if (pch->file.index == unit) {
2841                         list_move(&pch->list, &pn->all_channels);
2842                         return pch;
2843                 }
2844         }
2845
2846         list_for_each_entry(pch, &pn->all_channels, list) {
2847                 if (pch->file.index == unit)
2848                         return pch;
2849         }
2850
2851         return NULL;
2852 }
2853
2854 /*
2855  * Connect a PPP channel to a PPP interface unit.
2856  */
2857 static int
2858 ppp_connect_channel(struct channel *pch, int unit)
2859 {
2860         struct ppp *ppp;
2861         struct ppp_net *pn;
2862         int ret = -ENXIO;
2863         int hdrlen;
2864
2865         pn = ppp_pernet(pch->chan_net);
2866
2867         mutex_lock(&pn->all_ppp_mutex);
2868         ppp = ppp_find_unit(pn, unit);
2869         if (!ppp)
2870                 goto out;
2871         write_lock_bh(&pch->upl);
2872         ret = -EINVAL;
2873         if (pch->ppp)
2874                 goto outl;
2875
2876         ppp_lock(ppp);
2877         if (pch->file.hdrlen > ppp->file.hdrlen)
2878                 ppp->file.hdrlen = pch->file.hdrlen;
2879         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2880         if (hdrlen > ppp->dev->hard_header_len)
2881                 ppp->dev->hard_header_len = hdrlen;
2882         list_add_tail(&pch->clist, &ppp->channels);
2883         ++ppp->n_channels;
2884         pch->ppp = ppp;
2885         atomic_inc(&ppp->file.refcnt);
2886         ppp_unlock(ppp);
2887         ret = 0;
2888
2889  outl:
2890         write_unlock_bh(&pch->upl);
2891  out:
2892         mutex_unlock(&pn->all_ppp_mutex);
2893         return ret;
2894 }
2895
2896 /*
2897  * Disconnect a channel from its ppp unit.
2898  */
2899 static int
2900 ppp_disconnect_channel(struct channel *pch)
2901 {
2902         struct ppp *ppp;
2903         int err = -EINVAL;
2904
2905         write_lock_bh(&pch->upl);
2906         ppp = pch->ppp;
2907         pch->ppp = NULL;
2908         write_unlock_bh(&pch->upl);
2909         if (ppp) {
2910                 /* remove it from the ppp unit's list */
2911                 ppp_lock(ppp);
2912                 list_del(&pch->clist);
2913                 if (--ppp->n_channels == 0)
2914                         wake_up_interruptible(&ppp->file.rwait);
2915                 ppp_unlock(ppp);
2916                 if (atomic_dec_and_test(&ppp->file.refcnt))
2917                         ppp_destroy_interface(ppp);
2918                 err = 0;
2919         }
2920         return err;
2921 }
2922
2923 /*
2924  * Free up the resources used by a ppp channel.
2925  */
2926 static void ppp_destroy_channel(struct channel *pch)
2927 {
2928         atomic_dec(&channel_count);
2929
2930         if (!pch->file.dead) {
2931                 /* "can't happen" */
2932                 pr_err("ppp: destroying undead channel %p !\n", pch);
2933                 return;
2934         }
2935         skb_queue_purge(&pch->file.xq);
2936         skb_queue_purge(&pch->file.rq);
2937         kfree(pch);
2938 }
2939
2940 static void __exit ppp_cleanup(void)
2941 {
2942         /* should never happen */
2943         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2944                 pr_err("PPP: removing module but units remain!\n");
2945         unregister_chrdev(PPP_MAJOR, "ppp");
2946         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2947         class_destroy(ppp_class);
2948         unregister_pernet_device(&ppp_net_ops);
2949 }
2950
2951 /*
2952  * Units handling. Caller must protect concurrent access
2953  * by holding all_ppp_mutex
2954  */
2955
2956 /* associate pointer with specified number */
2957 static int unit_set(struct idr *p, void *ptr, int n)
2958 {
2959         int unit;
2960
2961         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
2962         if (unit == -ENOSPC)
2963                 unit = -EINVAL;
2964         return unit;
2965 }
2966
2967 /* get new free unit number and associate pointer with it */
2968 static int unit_get(struct idr *p, void *ptr)
2969 {
2970         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
2971 }
2972
2973 /* put unit number back to a pool */
2974 static void unit_put(struct idr *p, int n)
2975 {
2976         idr_remove(p, n);
2977 }
2978
2979 /* get pointer associated with the number */
2980 static void *unit_find(struct idr *p, int n)
2981 {
2982         return idr_find(p, n);
2983 }
2984
2985 /* Module/initialization stuff */
2986
2987 module_init(ppp_init);
2988 module_exit(ppp_cleanup);
2989
2990 EXPORT_SYMBOL(ppp_register_net_channel);
2991 EXPORT_SYMBOL(ppp_register_channel);
2992 EXPORT_SYMBOL(ppp_unregister_channel);
2993 EXPORT_SYMBOL(ppp_channel_index);
2994 EXPORT_SYMBOL(ppp_unit_number);
2995 EXPORT_SYMBOL(ppp_dev_name);
2996 EXPORT_SYMBOL(ppp_input);
2997 EXPORT_SYMBOL(ppp_input_error);
2998 EXPORT_SYMBOL(ppp_output_wakeup);
2999 EXPORT_SYMBOL(ppp_register_compressor);
3000 EXPORT_SYMBOL(ppp_unregister_compressor);
3001 MODULE_LICENSE("GPL");
3002 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3003 MODULE_ALIAS("devname:ppp");