Pileus Git - ~andy/linux/blob - 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 const struct net_device_ops ppp_netdev_ops = {
1062         .ndo_start_xmit  = ppp_start_xmit,
1063         .ndo_do_ioctl    = ppp_net_ioctl,
1064         .ndo_get_stats64 = ppp_get_stats64,
1065 };
1066
1067 static void ppp_setup(struct net_device *dev)
1068 {
1069         dev->netdev_ops = &ppp_netdev_ops;
1070         dev->hard_header_len = PPP_HDRLEN;
1071         dev->mtu = PPP_MRU;
1072         dev->addr_len = 0;
1073         dev->tx_queue_len = 3;
1074         dev->type = ARPHRD_PPP;
1075         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1076         dev->features |= NETIF_F_NETNS_LOCAL;
1077         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1078 }
1079
1080 /*
1081  * Transmit-side routines.
1082  */
1083
1084 /*
1085  * Called to do any work queued up on the transmit side
1086  * that can now be done.
1087  */
1088 static void
1089 ppp_xmit_process(struct ppp *ppp)
1090 {
1091         struct sk_buff *skb;
1092
1093         ppp_xmit_lock(ppp);
1094         if (!ppp->closing) {
1095                 ppp_push(ppp);
1096                 while (!ppp->xmit_pending &&
1097                        (skb = skb_dequeue(&ppp->file.xq)))
1098                         ppp_send_frame(ppp, skb);
1099                 /* If there's no work left to do, tell the core net
1100                    code that we can accept some more. */
1101                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1102                         netif_wake_queue(ppp->dev);
1103                 else
1104                         netif_stop_queue(ppp->dev);
1105         }
1106         ppp_xmit_unlock(ppp);
1107 }
1108
1109 static inline struct sk_buff *
1110 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1111 {
1112         struct sk_buff *new_skb;
1113         int len;
1114         int new_skb_size = ppp->dev->mtu +
1115                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1116         int compressor_skb_size = ppp->dev->mtu +
1117                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1118         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1119         if (!new_skb) {
1120                 if (net_ratelimit())
1121                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1122                 return NULL;
1123         }
1124         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1125                 skb_reserve(new_skb,
1126                             ppp->dev->hard_header_len - PPP_HDRLEN);
1127
1128         /* compressor still expects A/C bytes in hdr */
1129         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1130                                    new_skb->data, skb->len + 2,
1131                                    compressor_skb_size);
1132         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1133                 consume_skb(skb);
1134                 skb = new_skb;
1135                 skb_put(skb, len);
1136                 skb_pull(skb, 2);       /* pull off A/C bytes */
1137         } else if (len == 0) {
1138                 /* didn't compress, or CCP not up yet */
1139                 consume_skb(new_skb);
1140                 new_skb = skb;
1141         } else {
1142                 /*
1143                  * (len < 0)
1144                  * MPPE requires that we do not send unencrypted
1145                  * frames.  The compressor will return -1 if we
1146                  * should drop the frame.  We cannot simply test
1147                  * the compress_proto because MPPE and MPPC share
1148                  * the same number.
1149                  */
1150                 if (net_ratelimit())
1151                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1152                 kfree_skb(skb);
1153                 consume_skb(new_skb);
1154                 new_skb = NULL;
1155         }
1156         return new_skb;
1157 }
1158
1159 /*
1160  * Compress and send a frame.
1161  * The caller should have locked the xmit path,
1162  * and xmit_pending should be 0.
1163  */
1164 static void
1165 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1166 {
1167         int proto = PPP_PROTO(skb);
1168         struct sk_buff *new_skb;
1169         int len;
1170         unsigned char *cp;
1171
1172         if (proto < 0x8000) {
1173 #ifdef CONFIG_PPP_FILTER
1174                 /* check if we should pass this packet */
1175                 /* the filter instructions are constructed assuming
1176                    a four-byte PPP header on each packet */
1177                 *skb_push(skb, 2) = 1;
1178                 if (ppp->pass_filter &&
1179                     sk_run_filter(skb, ppp->pass_filter) == 0) {
1180                         if (ppp->debug & 1)
1181                                 netdev_printk(KERN_DEBUG, ppp->dev,
1182                                               "PPP: outbound frame "
1183                                               "not passed\n");
1184                         kfree_skb(skb);
1185                         return;
1186                 }
1187                 /* if this packet passes the active filter, record the time */
1188                 if (!(ppp->active_filter &&
1189                       sk_run_filter(skb, ppp->active_filter) == 0))
1190                         ppp->last_xmit = jiffies;
1191                 skb_pull(skb, 2);
1192 #else
1193                 /* for data packets, record the time */
1194                 ppp->last_xmit = jiffies;
1195 #endif /* CONFIG_PPP_FILTER */
1196         }
1197
1198         ++ppp->stats64.tx_packets;
1199         ppp->stats64.tx_bytes += skb->len - 2;
1200
1201         switch (proto) {
1202         case PPP_IP:
1203                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1204                         break;
1205                 /* try to do VJ TCP header compression */
1206                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1207                                     GFP_ATOMIC);
1208                 if (!new_skb) {
1209                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1210                         goto drop;
1211                 }
1212                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1213                 cp = skb->data + 2;
1214                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1215                                     new_skb->data + 2, &cp,
1216                                     !(ppp->flags & SC_NO_TCP_CCID));
1217                 if (cp == skb->data + 2) {
1218                         /* didn't compress */
1219                         consume_skb(new_skb);
1220                 } else {
1221                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1222                                 proto = PPP_VJC_COMP;
1223                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1224                         } else {
1225                                 proto = PPP_VJC_UNCOMP;
1226                                 cp[0] = skb->data[2];
1227                         }
1228                         consume_skb(skb);
1229                         skb = new_skb;
1230                         cp = skb_put(skb, len + 2);
1231                         cp[0] = 0;
1232                         cp[1] = proto;
1233                 }
1234                 break;
1235
1236         case PPP_CCP:
1237                 /* peek at outbound CCP frames */
1238                 ppp_ccp_peek(ppp, skb, 0);
1239                 break;
1240         }
1241
1242         /* try to do packet compression */
1243         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1244             proto != PPP_LCP && proto != PPP_CCP) {
1245                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1246                         if (net_ratelimit())
1247                                 netdev_err(ppp->dev,
1248                                            "ppp: compression required but "
1249                                            "down - pkt dropped.\n");
1250                         goto drop;
1251                 }
1252                 skb = pad_compress_skb(ppp, skb);
1253                 if (!skb)
1254                         goto drop;
1255         }
1256
1257         /*
1258          * If we are waiting for traffic (demand dialling),
1259          * queue it up for pppd to receive.
1260          */
1261         if (ppp->flags & SC_LOOP_TRAFFIC) {
1262                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1263                         goto drop;
1264                 skb_queue_tail(&ppp->file.rq, skb);
1265                 wake_up_interruptible(&ppp->file.rwait);
1266                 return;
1267         }
1268
1269         ppp->xmit_pending = skb;
1270         ppp_push(ppp);
1271         return;
1272
1273  drop:
1274         kfree_skb(skb);
1275         ++ppp->dev->stats.tx_errors;
1276 }
1277
1278 /*
1279  * Try to send the frame in xmit_pending.
1280  * The caller should have the xmit path locked.
1281  */
1282 static void
1283 ppp_push(struct ppp *ppp)
1284 {
1285         struct list_head *list;
1286         struct channel *pch;
1287         struct sk_buff *skb = ppp->xmit_pending;
1288
1289         if (!skb)
1290                 return;
1291
1292         list = &ppp->channels;
1293         if (list_empty(list)) {
1294                 /* nowhere to send the packet, just drop it */
1295                 ppp->xmit_pending = NULL;
1296                 kfree_skb(skb);
1297                 return;
1298         }
1299
1300         if ((ppp->flags & SC_MULTILINK) == 0) {
1301                 /* not doing multilink: send it down the first channel */
1302                 list = list->next;
1303                 pch = list_entry(list, struct channel, clist);
1304
1305                 spin_lock_bh(&pch->downl);
1306                 if (pch->chan) {
1307                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1308                                 ppp->xmit_pending = NULL;
1309                 } else {
1310                         /* channel got unregistered */
1311                         kfree_skb(skb);
1312                         ppp->xmit_pending = NULL;
1313                 }
1314                 spin_unlock_bh(&pch->downl);
1315                 return;
1316         }
1317
1318 #ifdef CONFIG_PPP_MULTILINK
1319         /* Multilink: fragment the packet over as many links
1320            as can take the packet at the moment. */
1321         if (!ppp_mp_explode(ppp, skb))
1322                 return;
1323 #endif /* CONFIG_PPP_MULTILINK */
1324
1325         ppp->xmit_pending = NULL;
1326         kfree_skb(skb);
1327 }
1328
1329 #ifdef CONFIG_PPP_MULTILINK
1330 static bool mp_protocol_compress __read_mostly = true;
1331 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1332 MODULE_PARM_DESC(mp_protocol_compress,
1333                  "compress protocol id in multilink fragments");
1334
1335 /*
1336  * Divide a packet to be transmitted into fragments and
1337  * send them out the individual links.
1338  */
1339 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1340 {
1341         int len, totlen;
1342         int i, bits, hdrlen, mtu;
1343         int flen;
1344         int navail, nfree, nzero;
1345         int nbigger;
1346         int totspeed;
1347         int totfree;
1348         unsigned char *p, *q;
1349         struct list_head *list;
1350         struct channel *pch;
1351         struct sk_buff *frag;
1352         struct ppp_channel *chan;
1353
1354         totspeed = 0; /*total bitrate of the bundle*/
1355         nfree = 0; /* # channels which have no packet already queued */
1356         navail = 0; /* total # of usable channels (not deregistered) */
1357         nzero = 0; /* number of channels with zero speed associated*/
1358         totfree = 0; /*total # of channels available and
1359                                   *having no queued packets before
1360                                   *starting the fragmentation*/
1361
1362         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1363         i = 0;
1364         list_for_each_entry(pch, &ppp->channels, clist) {
1365                 if (pch->chan) {
1366                         pch->avail = 1;
1367                         navail++;
1368                         pch->speed = pch->chan->speed;
1369                 } else {
1370                         pch->avail = 0;
1371                 }
1372                 if (pch->avail) {
1373                         if (skb_queue_empty(&pch->file.xq) ||
1374                                 !pch->had_frag) {
1375                                         if (pch->speed == 0)
1376                                                 nzero++;
1377                                         else
1378                                                 totspeed += pch->speed;
1379
1380                                         pch->avail = 2;
1381                                         ++nfree;
1382                                         ++totfree;
1383                                 }
1384                         if (!pch->had_frag && i < ppp->nxchan)
1385                                 ppp->nxchan = i;
1386                 }
1387                 ++i;
1388         }
1389         /*
1390          * Don't start sending this packet unless at least half of
1391          * the channels are free.  This gives much better TCP
1392          * performance if we have a lot of channels.
1393          */
1394         if (nfree == 0 || nfree < navail / 2)
1395                 return 0; /* can't take now, leave it in xmit_pending */
1396
1397         /* Do protocol field compression */
1398         p = skb->data;
1399         len = skb->len;
1400         if (*p == 0 && mp_protocol_compress) {
1401                 ++p;
1402                 --len;
1403         }
1404
1405         totlen = len;
1406         nbigger = len % nfree;
1407
1408         /* skip to the channel after the one we last used
1409            and start at that one */
1410         list = &ppp->channels;
1411         for (i = 0; i < ppp->nxchan; ++i) {
1412                 list = list->next;
1413                 if (list == &ppp->channels) {
1414                         i = 0;
1415                         break;
1416                 }
1417         }
1418
1419         /* create a fragment for each channel */
1420         bits = B;
1421         while (len > 0) {
1422                 list = list->next;
1423                 if (list == &ppp->channels) {
1424                         i = 0;
1425                         continue;
1426                 }
1427                 pch = list_entry(list, struct channel, clist);
1428                 ++i;
1429                 if (!pch->avail)
1430                         continue;
1431
1432                 /*
1433                  * Skip this channel if it has a fragment pending already and
1434                  * we haven't given a fragment to all of the free channels.
1435                  */
1436                 if (pch->avail == 1) {
1437                         if (nfree > 0)
1438                                 continue;
1439                 } else {
1440                         pch->avail = 1;
1441                 }
1442
1443                 /* check the channel's mtu and whether it is still attached. */
1444                 spin_lock_bh(&pch->downl);
1445                 if (pch->chan == NULL) {
1446                         /* can't use this channel, it's being deregistered */
1447                         if (pch->speed == 0)
1448                                 nzero--;
1449                         else
1450                                 totspeed -= pch->speed;
1451
1452                         spin_unlock_bh(&pch->downl);
1453                         pch->avail = 0;
1454                         totlen = len;
1455                         totfree--;
1456                         nfree--;
1457                         if (--navail == 0)
1458                                 break;
1459                         continue;
1460                 }
1461
1462                 /*
1463                 *if the channel speed is not set divide
1464                 *the packet evenly among the free channels;
1465                 *otherwise divide it according to the speed
1466                 *of the channel we are going to transmit on
1467                 */
1468                 flen = len;
1469                 if (nfree > 0) {
1470                         if (pch->speed == 0) {
1471                                 flen = len/nfree;
1472                                 if (nbigger > 0) {
1473                                         flen++;
1474                                         nbigger--;
1475                                 }
1476                         } else {
1477                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1478                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1479                                 if (nbigger > 0) {
1480                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1481                                         nbigger -= ((totfree - nzero)*pch->speed)/
1482                                                         totspeed;
1483                                 }
1484                         }
1485                         nfree--;
1486                 }
1487
1488                 /*
1489                  *check if we are on the last channel or
1490                  *we exceded the length of the data to
1491                  *fragment
1492                  */
1493                 if ((nfree <= 0) || (flen > len))
1494                         flen = len;
1495                 /*
1496                  *it is not worth to tx on slow channels:
1497                  *in that case from the resulting flen according to the
1498                  *above formula will be equal or less than zero.
1499                  *Skip the channel in this case
1500                  */
1501                 if (flen <= 0) {
1502                         pch->avail = 2;
1503                         spin_unlock_bh(&pch->downl);
1504                         continue;
1505                 }
1506
1507                 /*
1508                  * hdrlen includes the 2-byte PPP protocol field, but the
1509                  * MTU counts only the payload excluding the protocol field.
1510                  * (RFC1661 Section 2)
1511                  */
1512                 mtu = pch->chan->mtu - (hdrlen - 2);
1513                 if (mtu < 4)
1514                         mtu = 4;
1515                 if (flen > mtu)
1516                         flen = mtu;
1517                 if (flen == len)
1518                         bits |= E;
1519                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1520                 if (!frag)
1521                         goto noskb;
1522                 q = skb_put(frag, flen + hdrlen);
1523
1524                 /* make the MP header */
1525                 put_unaligned_be16(PPP_MP, q);
1526                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1527                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1528                         q[3] = ppp->nxseq;
1529                 } else {
1530                         q[2] = bits;
1531                         q[3] = ppp->nxseq >> 16;
1532                         q[4] = ppp->nxseq >> 8;
1533                         q[5] = ppp->nxseq;
1534                 }
1535
1536                 memcpy(q + hdrlen, p, flen);
1537
1538                 /* try to send it down the channel */
1539                 chan = pch->chan;
1540                 if (!skb_queue_empty(&pch->file.xq) ||
1541                         !chan->ops->start_xmit(chan, frag))
1542                         skb_queue_tail(&pch->file.xq, frag);
1543                 pch->had_frag = 1;
1544                 p += flen;
1545                 len -= flen;
1546                 ++ppp->nxseq;
1547                 bits = 0;
1548                 spin_unlock_bh(&pch->downl);
1549         }
1550         ppp->nxchan = i;
1551
1552         return 1;
1553
1554  noskb:
1555         spin_unlock_bh(&pch->downl);
1556         if (ppp->debug & 1)
1557                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1558         ++ppp->dev->stats.tx_errors;
1559         ++ppp->nxseq;
1560         return 1;       /* abandon the frame */
1561 }
1562 #endif /* CONFIG_PPP_MULTILINK */
1563
1564 /*
1565  * Try to send data out on a channel.
1566  */
1567 static void
1568 ppp_channel_push(struct channel *pch)
1569 {
1570         struct sk_buff *skb;
1571         struct ppp *ppp;
1572
1573         spin_lock_bh(&pch->downl);
1574         if (pch->chan) {
1575                 while (!skb_queue_empty(&pch->file.xq)) {
1576                         skb = skb_dequeue(&pch->file.xq);
1577                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1578                                 /* put the packet back and try again later */
1579                                 skb_queue_head(&pch->file.xq, skb);
1580                                 break;
1581                         }
1582                 }
1583         } else {
1584                 /* channel got deregistered */
1585                 skb_queue_purge(&pch->file.xq);
1586         }
1587         spin_unlock_bh(&pch->downl);
1588         /* see if there is anything from the attached unit to be sent */
1589         if (skb_queue_empty(&pch->file.xq)) {
1590                 read_lock_bh(&pch->upl);
1591                 ppp = pch->ppp;
1592                 if (ppp)
1593                         ppp_xmit_process(ppp);
1594                 read_unlock_bh(&pch->upl);
1595         }
1596 }
1597
1598 /*
1599  * Receive-side routines.
1600  */
1601
1602 struct ppp_mp_skb_parm {
1603         u32             sequence;
1604         u8              BEbits;
1605 };
1606 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1607
1608 static inline void
1609 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1610 {
1611         ppp_recv_lock(ppp);
1612         if (!ppp->closing)
1613                 ppp_receive_frame(ppp, skb, pch);
1614         else
1615                 kfree_skb(skb);
1616         ppp_recv_unlock(ppp);
1617 }
1618
1619 void
1620 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1621 {
1622         struct channel *pch = chan->ppp;
1623         int proto;
1624
1625         if (!pch) {
1626                 kfree_skb(skb);
1627                 return;
1628         }
1629
1630         read_lock_bh(&pch->upl);
1631         if (!pskb_may_pull(skb, 2)) {
1632                 kfree_skb(skb);
1633                 if (pch->ppp) {
1634                         ++pch->ppp->dev->stats.rx_length_errors;
1635                         ppp_receive_error(pch->ppp);
1636                 }
1637                 goto done;
1638         }
1639
1640         proto = PPP_PROTO(skb);
1641         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1642                 /* put it on the channel queue */
1643                 skb_queue_tail(&pch->file.rq, skb);
1644                 /* drop old frames if queue too long */
1645                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1646                        (skb = skb_dequeue(&pch->file.rq)))
1647                         kfree_skb(skb);
1648                 wake_up_interruptible(&pch->file.rwait);
1649         } else {
1650                 ppp_do_recv(pch->ppp, skb, pch);
1651         }
1652
1653 done:
1654         read_unlock_bh(&pch->upl);
1655 }
1656
1657 /* Put a 0-length skb in the receive queue as an error indication */
1658 void
1659 ppp_input_error(struct ppp_channel *chan, int code)
1660 {
1661         struct channel *pch = chan->ppp;
1662         struct sk_buff *skb;
1663
1664         if (!pch)
1665                 return;
1666
1667         read_lock_bh(&pch->upl);
1668         if (pch->ppp) {
1669                 skb = alloc_skb(0, GFP_ATOMIC);
1670                 if (skb) {
1671                         skb->len = 0;           /* probably unnecessary */
1672                         skb->cb[0] = code;
1673                         ppp_do_recv(pch->ppp, skb, pch);
1674                 }
1675         }
1676         read_unlock_bh(&pch->upl);
1677 }
1678
1679 /*
1680  * We come in here to process a received frame.
1681  * The receive side of the ppp unit is locked.
1682  */
1683 static void
1684 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1685 {
1686         /* note: a 0-length skb is used as an error indication */
1687         if (skb->len > 0) {
1688 #ifdef CONFIG_PPP_MULTILINK
1689                 /* XXX do channel-level decompression here */
1690                 if (PPP_PROTO(skb) == PPP_MP)
1691                         ppp_receive_mp_frame(ppp, skb, pch);
1692                 else
1693 #endif /* CONFIG_PPP_MULTILINK */
1694                         ppp_receive_nonmp_frame(ppp, skb);
1695         } else {
1696                 kfree_skb(skb);
1697                 ppp_receive_error(ppp);
1698         }
1699 }
1700
1701 static void
1702 ppp_receive_error(struct ppp *ppp)
1703 {
1704         ++ppp->dev->stats.rx_errors;
1705         if (ppp->vj)
1706                 slhc_toss(ppp->vj);
1707 }
1708
1709 static void
1710 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1711 {
1712         struct sk_buff *ns;
1713         int proto, len, npi;
1714
1715         /*
1716          * Decompress the frame, if compressed.
1717          * Note that some decompressors need to see uncompressed frames
1718          * that come in as well as compressed frames.
1719          */
1720         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1721             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1722                 skb = ppp_decompress_frame(ppp, skb);
1723
1724         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1725                 goto err;
1726
1727         proto = PPP_PROTO(skb);
1728         switch (proto) {
1729         case PPP_VJC_COMP:
1730                 /* decompress VJ compressed packets */
1731                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1732                         goto err;
1733
1734                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1735                         /* copy to a new sk_buff with more tailroom */
1736                         ns = dev_alloc_skb(skb->len + 128);
1737                         if (!ns) {
1738                                 netdev_err(ppp->dev, "PPP: no memory "
1739                                            "(VJ decomp)\n");
1740                                 goto err;
1741                         }
1742                         skb_reserve(ns, 2);
1743                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1744                         consume_skb(skb);
1745                         skb = ns;
1746                 }
1747                 else
1748                         skb->ip_summed = CHECKSUM_NONE;
1749
1750                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1751                 if (len <= 0) {
1752                         netdev_printk(KERN_DEBUG, ppp->dev,
1753                                       "PPP: VJ decompression error\n");
1754                         goto err;
1755                 }
1756                 len += 2;
1757                 if (len > skb->len)
1758                         skb_put(skb, len - skb->len);
1759                 else if (len < skb->len)
1760                         skb_trim(skb, len);
1761                 proto = PPP_IP;
1762                 break;
1763
1764         case PPP_VJC_UNCOMP:
1765                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1766                         goto err;
1767
1768                 /* Until we fix the decompressor need to make sure
1769                  * data portion is linear.
1770                  */
1771                 if (!pskb_may_pull(skb, skb->len))
1772                         goto err;
1773
1774                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1775                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1776                         goto err;
1777                 }
1778                 proto = PPP_IP;
1779                 break;
1780
1781         case PPP_CCP:
1782                 ppp_ccp_peek(ppp, skb, 1);
1783                 break;
1784         }
1785
1786         ++ppp->stats64.rx_packets;
1787         ppp->stats64.rx_bytes += skb->len - 2;
1788
1789         npi = proto_to_npindex(proto);
1790         if (npi < 0) {
1791                 /* control or unknown frame - pass it to pppd */
1792                 skb_queue_tail(&ppp->file.rq, skb);
1793                 /* limit queue length by dropping old frames */
1794                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1795                        (skb = skb_dequeue(&ppp->file.rq)))
1796                         kfree_skb(skb);
1797                 /* wake up any process polling or blocking on read */
1798                 wake_up_interruptible(&ppp->file.rwait);
1799
1800         } else {
1801                 /* network protocol frame - give it to the kernel */
1802
1803 #ifdef CONFIG_PPP_FILTER
1804                 /* check if the packet passes the pass and active filters */
1805                 /* the filter instructions are constructed assuming
1806                    a four-byte PPP header on each packet */
1807                 if (ppp->pass_filter || ppp->active_filter) {
1808                         if (skb_unclone(skb, GFP_ATOMIC))
1809                                 goto err;
1810
1811                         *skb_push(skb, 2) = 0;
1812                         if (ppp->pass_filter &&
1813                             sk_run_filter(skb, ppp->pass_filter) == 0) {
1814                                 if (ppp->debug & 1)
1815                                         netdev_printk(KERN_DEBUG, ppp->dev,
1816                                                       "PPP: inbound frame "
1817                                                       "not passed\n");
1818                                 kfree_skb(skb);
1819                                 return;
1820                         }
1821                         if (!(ppp->active_filter &&
1822                               sk_run_filter(skb, ppp->active_filter) == 0))
1823                                 ppp->last_recv = jiffies;
1824                         __skb_pull(skb, 2);
1825                 } else
1826 #endif /* CONFIG_PPP_FILTER */
1827                         ppp->last_recv = jiffies;
1828
1829                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1830                     ppp->npmode[npi] != NPMODE_PASS) {
1831                         kfree_skb(skb);
1832                 } else {
1833                         /* chop off protocol */
1834                         skb_pull_rcsum(skb, 2);
1835                         skb->dev = ppp->dev;
1836                         skb->protocol = htons(npindex_to_ethertype[npi]);
1837                         skb_reset_mac_header(skb);
1838                         netif_rx(skb);
1839                 }
1840         }
1841         return;
1842
1843  err:
1844         kfree_skb(skb);
1845         ppp_receive_error(ppp);
1846 }
1847
1848 static struct sk_buff *
1849 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1850 {
1851         int proto = PPP_PROTO(skb);
1852         struct sk_buff *ns;
1853         int len;
1854
1855         /* Until we fix all the decompressor's need to make sure
1856          * data portion is linear.
1857          */
1858         if (!pskb_may_pull(skb, skb->len))
1859                 goto err;
1860
1861         if (proto == PPP_COMP) {
1862                 int obuff_size;
1863
1864                 switch(ppp->rcomp->compress_proto) {
1865                 case CI_MPPE:
1866                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1867                         break;
1868                 default:
1869                         obuff_size = ppp->mru + PPP_HDRLEN;
1870                         break;
1871                 }
1872
1873                 ns = dev_alloc_skb(obuff_size);
1874                 if (!ns) {
1875                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1876                                    "no memory\n");
1877                         goto err;
1878                 }
1879                 /* the decompressor still expects the A/C bytes in the hdr */
1880                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1881                                 skb->len + 2, ns->data, obuff_size);
1882                 if (len < 0) {
1883                         /* Pass the compressed frame to pppd as an
1884                            error indication. */
1885                         if (len == DECOMP_FATALERROR)
1886                                 ppp->rstate |= SC_DC_FERROR;
1887                         kfree_skb(ns);
1888                         goto err;
1889                 }
1890
1891                 consume_skb(skb);
1892                 skb = ns;
1893                 skb_put(skb, len);
1894                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1895
1896         } else {
1897                 /* Uncompressed frame - pass to decompressor so it
1898                    can update its dictionary if necessary. */
1899                 if (ppp->rcomp->incomp)
1900                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1901                                            skb->len + 2);
1902         }
1903
1904         return skb;
1905
1906  err:
1907         ppp->rstate |= SC_DC_ERROR;
1908         ppp_receive_error(ppp);
1909         return skb;
1910 }
1911
1912 #ifdef CONFIG_PPP_MULTILINK
1913 /*
1914  * Receive a multilink frame.
1915  * We put it on the reconstruction queue and then pull off
1916  * as many completed frames as we can.
1917  */
1918 static void
1919 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1920 {
1921         u32 mask, seq;
1922         struct channel *ch;
1923         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1924
1925         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1926                 goto err;               /* no good, throw it away */
1927
1928         /* Decode sequence number and begin/end bits */
1929         if (ppp->flags & SC_MP_SHORTSEQ) {
1930                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1931                 mask = 0xfff;
1932         } else {
1933                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1934                 mask = 0xffffff;
1935         }
1936         PPP_MP_CB(skb)->BEbits = skb->data[2];
1937         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1938
1939         /*
1940          * Do protocol ID decompression on the first fragment of each packet.
1941          */
1942         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
1943                 *skb_push(skb, 1) = 0;
1944
1945         /*
1946          * Expand sequence number to 32 bits, making it as close
1947          * as possible to ppp->minseq.
1948          */
1949         seq |= ppp->minseq & ~mask;
1950         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1951                 seq += mask + 1;
1952         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1953                 seq -= mask + 1;        /* should never happen */
1954         PPP_MP_CB(skb)->sequence = seq;
1955         pch->lastseq = seq;
1956
1957         /*
1958          * If this packet comes before the next one we were expecting,
1959          * drop it.
1960          */
1961         if (seq_before(seq, ppp->nextseq)) {
1962                 kfree_skb(skb);
1963                 ++ppp->dev->stats.rx_dropped;
1964                 ppp_receive_error(ppp);
1965                 return;
1966         }
1967
1968         /*
1969          * Reevaluate minseq, the minimum over all channels of the
1970          * last sequence number received on each channel.  Because of
1971          * the increasing sequence number rule, we know that any fragment
1972          * before `minseq' which hasn't arrived is never going to arrive.
1973          * The list of channels can't change because we have the receive
1974          * side of the ppp unit locked.
1975          */
1976         list_for_each_entry(ch, &ppp->channels, clist) {
1977                 if (seq_before(ch->lastseq, seq))
1978                         seq = ch->lastseq;
1979         }
1980         if (seq_before(ppp->minseq, seq))
1981                 ppp->minseq = seq;
1982
1983         /* Put the fragment on the reconstruction queue */
1984         ppp_mp_insert(ppp, skb);
1985
1986         /* If the queue is getting long, don't wait any longer for packets
1987            before the start of the queue. */
1988         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1989                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
1990                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
1991                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
1992         }
1993
1994         /* Pull completed packets off the queue and receive them. */
1995         while ((skb = ppp_mp_reconstruct(ppp))) {
1996                 if (pskb_may_pull(skb, 2))
1997                         ppp_receive_nonmp_frame(ppp, skb);
1998                 else {
1999                         ++ppp->dev->stats.rx_length_errors;
2000                         kfree_skb(skb);
2001                         ppp_receive_error(ppp);
2002                 }
2003         }
2004
2005         return;
2006
2007  err:
2008         kfree_skb(skb);
2009         ppp_receive_error(ppp);
2010 }
2011
2012 /*
2013  * Insert a fragment on the MP reconstruction queue.
2014  * The queue is ordered by increasing sequence number.
2015  */
2016 static void
2017 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2018 {
2019         struct sk_buff *p;
2020         struct sk_buff_head *list = &ppp->mrq;
2021         u32 seq = PPP_MP_CB(skb)->sequence;
2022
2023         /* N.B. we don't need to lock the list lock because we have the
2024            ppp unit receive-side lock. */
2025         skb_queue_walk(list, p) {
2026                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2027                         break;
2028         }
2029         __skb_queue_before(list, p, skb);
2030 }
2031
2032 /*
2033  * Reconstruct a packet from the MP fragment queue.
2034  * We go through increasing sequence numbers until we find a
2035  * complete packet, or we get to the sequence number for a fragment
2036  * which hasn't arrived but might still do so.
2037  */
2038 static struct sk_buff *
2039 ppp_mp_reconstruct(struct ppp *ppp)
2040 {
2041         u32 seq = ppp->nextseq;
2042         u32 minseq = ppp->minseq;
2043         struct sk_buff_head *list = &ppp->mrq;
2044         struct sk_buff *p, *tmp;
2045         struct sk_buff *head, *tail;
2046         struct sk_buff *skb = NULL;
2047         int lost = 0, len = 0;
2048
2049         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2050                 return NULL;
2051         head = list->next;
2052         tail = NULL;
2053         skb_queue_walk_safe(list, p, tmp) {
2054         again:
2055                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2056                         /* this can't happen, anyway ignore the skb */
2057                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2058                                    "seq %u < %u\n",
2059                                    PPP_MP_CB(p)->sequence, seq);
2060                         __skb_unlink(p, list);
2061                         kfree_skb(p);
2062                         continue;
2063                 }
2064                 if (PPP_MP_CB(p)->sequence != seq) {
2065                         u32 oldseq;
2066                         /* Fragment `seq' is missing.  If it is after
2067                            minseq, it might arrive later, so stop here. */
2068                         if (seq_after(seq, minseq))
2069                                 break;
2070                         /* Fragment `seq' is lost, keep going. */
2071                         lost = 1;
2072                         oldseq = seq;
2073                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2074                                 minseq + 1: PPP_MP_CB(p)->sequence;
2075
2076                         if (ppp->debug & 1)
2077                                 netdev_printk(KERN_DEBUG, ppp->dev,
2078                                               "lost frag %u..%u\n",
2079                                               oldseq, seq-1);
2080
2081                         goto again;
2082                 }
2083
2084                 /*
2085                  * At this point we know that all the fragments from
2086                  * ppp->nextseq to seq are either present or lost.
2087                  * Also, there are no complete packets in the queue
2088                  * that have no missing fragments and end before this
2089                  * fragment.
2090                  */
2091
2092                 /* B bit set indicates this fragment starts a packet */
2093                 if (PPP_MP_CB(p)->BEbits & B) {
2094                         head = p;
2095                         lost = 0;
2096                         len = 0;
2097                 }
2098
2099                 len += p->len;
2100
2101                 /* Got a complete packet yet? */
2102                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2103                     (PPP_MP_CB(head)->BEbits & B)) {
2104                         if (len > ppp->mrru + 2) {
2105                                 ++ppp->dev->stats.rx_length_errors;
2106                                 netdev_printk(KERN_DEBUG, ppp->dev,
2107                                               "PPP: reconstructed packet"
2108                                               " is too long (%d)\n", len);
2109                         } else {
2110                                 tail = p;
2111                                 break;
2112                         }
2113                         ppp->nextseq = seq + 1;
2114                 }
2115
2116                 /*
2117                  * If this is the ending fragment of a packet,
2118                  * and we haven't found a complete valid packet yet,
2119                  * we can discard up to and including this fragment.
2120                  */
2121                 if (PPP_MP_CB(p)->BEbits & E) {
2122                         struct sk_buff *tmp2;
2123
2124                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2125                                 if (ppp->debug & 1)
2126                                         netdev_printk(KERN_DEBUG, ppp->dev,
2127                                                       "discarding frag %u\n",
2128                                                       PPP_MP_CB(p)->sequence);
2129                                 __skb_unlink(p, list);
2130                                 kfree_skb(p);
2131                         }
2132                         head = skb_peek(list);
2133                         if (!head)
2134                                 break;
2135                 }
2136                 ++seq;
2137         }
2138
2139         /* If we have a complete packet, copy it all into one skb. */
2140         if (tail != NULL) {
2141                 /* If we have discarded any fragments,
2142                    signal a receive error. */
2143                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2144                         skb_queue_walk_safe(list, p, tmp) {
2145                                 if (p == head)
2146                                         break;
2147                                 if (ppp->debug & 1)
2148                                         netdev_printk(KERN_DEBUG, ppp->dev,
2149                                                       "discarding frag %u\n",
2150                                                       PPP_MP_CB(p)->sequence);
2151                                 __skb_unlink(p, list);
2152                                 kfree_skb(p);
2153                         }
2154
2155                         if (ppp->debug & 1)
2156                                 netdev_printk(KERN_DEBUG, ppp->dev,
2157                                               "  missed pkts %u..%u\n",
2158                                               ppp->nextseq,
2159                                               PPP_MP_CB(head)->sequence-1);
2160                         ++ppp->dev->stats.rx_dropped;
2161                         ppp_receive_error(ppp);
2162                 }
2163
2164                 skb = head;
2165                 if (head != tail) {
2166                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2167                         p = skb_queue_next(list, head);
2168                         __skb_unlink(skb, list);
2169                         skb_queue_walk_from_safe(list, p, tmp) {
2170                                 __skb_unlink(p, list);
2171                                 *fragpp = p;
2172                                 p->next = NULL;
2173                                 fragpp = &p->next;
2174
2175                                 skb->len += p->len;
2176                                 skb->data_len += p->len;
2177                                 skb->truesize += p->truesize;
2178
2179                                 if (p == tail)
2180                                         break;
2181                         }
2182                 } else {
2183                         __skb_unlink(skb, list);
2184                 }
2185
2186                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2187         }
2188
2189         return skb;
2190 }
2191 #endif /* CONFIG_PPP_MULTILINK */
2192
2193 /*
2194  * Channel interface.
2195  */
2196
2197 /* Create a new, unattached ppp channel. */
2198 int ppp_register_channel(struct ppp_channel *chan)
2199 {
2200         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2201 }
2202
2203 /* Create a new, unattached ppp channel for specified net. */
2204 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2205 {
2206         struct channel *pch;
2207         struct ppp_net *pn;
2208
2209         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2210         if (!pch)
2211                 return -ENOMEM;
2212
2213         pn = ppp_pernet(net);
2214
2215         pch->ppp = NULL;
2216         pch->chan = chan;
2217         pch->chan_net = net;
2218         chan->ppp = pch;
2219         init_ppp_file(&pch->file, CHANNEL);
2220         pch->file.hdrlen = chan->hdrlen;
2221 #ifdef CONFIG_PPP_MULTILINK
2222         pch->lastseq = -1;
2223 #endif /* CONFIG_PPP_MULTILINK */
2224         init_rwsem(&pch->chan_sem);
2225         spin_lock_init(&pch->downl);
2226         rwlock_init(&pch->upl);
2227
2228         spin_lock_bh(&pn->all_channels_lock);
2229         pch->file.index = ++pn->last_channel_index;
2230         list_add(&pch->list, &pn->new_channels);
2231         atomic_inc(&channel_count);
2232         spin_unlock_bh(&pn->all_channels_lock);
2233
2234         return 0;
2235 }
2236
2237 /*
2238  * Return the index of a channel.
2239  */
2240 int ppp_channel_index(struct ppp_channel *chan)
2241 {
2242         struct channel *pch = chan->ppp;
2243
2244         if (pch)
2245                 return pch->file.index;
2246         return -1;
2247 }
2248
2249 /*
2250  * Return the PPP unit number to which a channel is connected.
2251  */
2252 int ppp_unit_number(struct ppp_channel *chan)
2253 {
2254         struct channel *pch = chan->ppp;
2255         int unit = -1;
2256
2257         if (pch) {
2258                 read_lock_bh(&pch->upl);
2259                 if (pch->ppp)
2260                         unit = pch->ppp->file.index;
2261                 read_unlock_bh(&pch->upl);
2262         }
2263         return unit;
2264 }
2265
2266 /*
2267  * Return the PPP device interface name of a channel.
2268  */
2269 char *ppp_dev_name(struct ppp_channel *chan)
2270 {
2271         struct channel *pch = chan->ppp;
2272         char *name = NULL;
2273
2274         if (pch) {
2275                 read_lock_bh(&pch->upl);
2276                 if (pch->ppp && pch->ppp->dev)
2277                         name = pch->ppp->dev->name;
2278                 read_unlock_bh(&pch->upl);
2279         }
2280         return name;
2281 }
2282
2283
2284 /*
2285  * Disconnect a channel from the generic layer.
2286  * This must be called in process context.
2287  */
2288 void
2289 ppp_unregister_channel(struct ppp_channel *chan)
2290 {
2291         struct channel *pch = chan->ppp;
2292         struct ppp_net *pn;
2293
2294         if (!pch)
2295                 return;         /* should never happen */
2296
2297         chan->ppp = NULL;
2298
2299         /*
2300          * This ensures that we have returned from any calls into the
2301          * the channel's start_xmit or ioctl routine before we proceed.
2302          */
2303         down_write(&pch->chan_sem);
2304         spin_lock_bh(&pch->downl);
2305         pch->chan = NULL;
2306         spin_unlock_bh(&pch->downl);
2307         up_write(&pch->chan_sem);
2308         ppp_disconnect_channel(pch);
2309
2310         pn = ppp_pernet(pch->chan_net);
2311         spin_lock_bh(&pn->all_channels_lock);
2312         list_del(&pch->list);
2313         spin_unlock_bh(&pn->all_channels_lock);
2314
2315         pch->file.dead = 1;
2316         wake_up_interruptible(&pch->file.rwait);
2317         if (atomic_dec_and_test(&pch->file.refcnt))
2318                 ppp_destroy_channel(pch);
2319 }
2320
2321 /*
2322  * Callback from a channel when it can accept more to transmit.
2323  * This should be called at BH/softirq level, not interrupt level.
2324  */
2325 void
2326 ppp_output_wakeup(struct ppp_channel *chan)
2327 {
2328         struct channel *pch = chan->ppp;
2329
2330         if (!pch)
2331                 return;
2332         ppp_channel_push(pch);
2333 }
2334
2335 /*
2336  * Compression control.
2337  */
2338
2339 /* Process the PPPIOCSCOMPRESS ioctl. */
2340 static int
2341 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2342 {
2343         int err;
2344         struct compressor *cp, *ocomp;
2345         struct ppp_option_data data;
2346         void *state, *ostate;
2347         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2348
2349         err = -EFAULT;
2350         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2351             (data.length <= CCP_MAX_OPTION_LENGTH &&
2352              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2353                 goto out;
2354         err = -EINVAL;
2355         if (data.length > CCP_MAX_OPTION_LENGTH ||
2356             ccp_option[1] < 2 || ccp_option[1] > data.length)
2357                 goto out;
2358
2359         cp = try_then_request_module(
2360                 find_compressor(ccp_option[0]),
2361                 "ppp-compress-%d", ccp_option[0]);
2362         if (!cp)
2363                 goto out;
2364
2365         err = -ENOBUFS;
2366         if (data.transmit) {
2367                 state = cp->comp_alloc(ccp_option, data.length);
2368                 if (state) {
2369                         ppp_xmit_lock(ppp);
2370                         ppp->xstate &= ~SC_COMP_RUN;
2371                         ocomp = ppp->xcomp;
2372                         ostate = ppp->xc_state;
2373                         ppp->xcomp = cp;
2374                         ppp->xc_state = state;
2375                         ppp_xmit_unlock(ppp);
2376                         if (ostate) {
2377                                 ocomp->comp_free(ostate);
2378                                 module_put(ocomp->owner);
2379                         }
2380                         err = 0;
2381                 } else
2382                         module_put(cp->owner);
2383
2384         } else {
2385                 state = cp->decomp_alloc(ccp_option, data.length);
2386                 if (state) {
2387                         ppp_recv_lock(ppp);
2388                         ppp->rstate &= ~SC_DECOMP_RUN;
2389                         ocomp = ppp->rcomp;
2390                         ostate = ppp->rc_state;
2391                         ppp->rcomp = cp;
2392                         ppp->rc_state = state;
2393                         ppp_recv_unlock(ppp);
2394                         if (ostate) {
2395                                 ocomp->decomp_free(ostate);
2396                                 module_put(ocomp->owner);
2397                         }
2398                         err = 0;
2399                 } else
2400                         module_put(cp->owner);
2401         }
2402
2403  out:
2404         return err;
2405 }
2406
2407 /*
2408  * Look at a CCP packet and update our state accordingly.
2409  * We assume the caller has the xmit or recv path locked.
2410  */
2411 static void
2412 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2413 {
2414         unsigned char *dp;
2415         int len;
2416
2417         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2418                 return; /* no header */
2419         dp = skb->data + 2;
2420
2421         switch (CCP_CODE(dp)) {
2422         case CCP_CONFREQ:
2423
2424                 /* A ConfReq starts negotiation of compression
2425                  * in one direction of transmission,
2426                  * and hence brings it down...but which way?
2427                  *
2428                  * Remember:
2429                  * A ConfReq indicates what the sender would like to receive
2430                  */
2431                 if(inbound)
2432                         /* He is proposing what I should send */
2433                         ppp->xstate &= ~SC_COMP_RUN;
2434                 else
2435                         /* I am proposing to what he should send */
2436                         ppp->rstate &= ~SC_DECOMP_RUN;
2437
2438                 break;
2439
2440         case CCP_TERMREQ:
2441         case CCP_TERMACK:
2442                 /*
2443                  * CCP is going down, both directions of transmission
2444                  */
2445                 ppp->rstate &= ~SC_DECOMP_RUN;
2446                 ppp->xstate &= ~SC_COMP_RUN;
2447                 break;
2448
2449         case CCP_CONFACK:
2450                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2451                         break;
2452                 len = CCP_LENGTH(dp);
2453                 if (!pskb_may_pull(skb, len + 2))
2454                         return;         /* too short */
2455                 dp += CCP_HDRLEN;
2456                 len -= CCP_HDRLEN;
2457                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2458                         break;
2459                 if (inbound) {
2460                         /* we will start receiving compressed packets */
2461                         if (!ppp->rc_state)
2462                                 break;
2463                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2464                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2465                                 ppp->rstate |= SC_DECOMP_RUN;
2466                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2467                         }
2468                 } else {
2469                         /* we will soon start sending compressed packets */
2470                         if (!ppp->xc_state)
2471                                 break;
2472                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2473                                         ppp->file.index, 0, ppp->debug))
2474                                 ppp->xstate |= SC_COMP_RUN;
2475                 }
2476                 break;
2477
2478         case CCP_RESETACK:
2479                 /* reset the [de]compressor */
2480                 if ((ppp->flags & SC_CCP_UP) == 0)
2481                         break;
2482                 if (inbound) {
2483                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2484                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2485                                 ppp->rstate &= ~SC_DC_ERROR;
2486                         }
2487                 } else {
2488                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2489                                 ppp->xcomp->comp_reset(ppp->xc_state);
2490                 }
2491                 break;
2492         }
2493 }
2494
2495 /* Free up compression resources. */
2496 static void
2497 ppp_ccp_closed(struct ppp *ppp)
2498 {
2499         void *xstate, *rstate;
2500         struct compressor *xcomp, *rcomp;
2501
2502         ppp_lock(ppp);
2503         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2504         ppp->xstate = 0;
2505         xcomp = ppp->xcomp;
2506         xstate = ppp->xc_state;
2507         ppp->xc_state = NULL;
2508         ppp->rstate = 0;
2509         rcomp = ppp->rcomp;
2510         rstate = ppp->rc_state;
2511         ppp->rc_state = NULL;
2512         ppp_unlock(ppp);
2513
2514         if (xstate) {
2515                 xcomp->comp_free(xstate);
2516                 module_put(xcomp->owner);
2517         }
2518         if (rstate) {
2519                 rcomp->decomp_free(rstate);
2520                 module_put(rcomp->owner);
2521         }
2522 }
2523
2524 /* List of compressors. */
2525 static LIST_HEAD(compressor_list);
2526 static DEFINE_SPINLOCK(compressor_list_lock);
2527
2528 struct compressor_entry {
2529         struct list_head list;
2530         struct compressor *comp;
2531 };
2532
2533 static struct compressor_entry *
2534 find_comp_entry(int proto)
2535 {
2536         struct compressor_entry *ce;
2537
2538         list_for_each_entry(ce, &compressor_list, list) {
2539                 if (ce->comp->compress_proto == proto)
2540                         return ce;
2541         }
2542         return NULL;
2543 }
2544
2545 /* Register a compressor */
2546 int
2547 ppp_register_compressor(struct compressor *cp)
2548 {
2549         struct compressor_entry *ce;
2550         int ret;
2551         spin_lock(&compressor_list_lock);
2552         ret = -EEXIST;
2553         if (find_comp_entry(cp->compress_proto))
2554                 goto out;
2555         ret = -ENOMEM;
2556         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2557         if (!ce)
2558                 goto out;
2559         ret = 0;
2560         ce->comp = cp;
2561         list_add(&ce->list, &compressor_list);
2562  out:
2563         spin_unlock(&compressor_list_lock);
2564         return ret;
2565 }
2566
2567 /* Unregister a compressor */
2568 void
2569 ppp_unregister_compressor(struct compressor *cp)
2570 {
2571         struct compressor_entry *ce;
2572
2573         spin_lock(&compressor_list_lock);
2574         ce = find_comp_entry(cp->compress_proto);
2575         if (ce && ce->comp == cp) {
2576                 list_del(&ce->list);
2577                 kfree(ce);
2578         }
2579         spin_unlock(&compressor_list_lock);
2580 }
2581
2582 /* Find a compressor. */
2583 static struct compressor *
2584 find_compressor(int type)
2585 {
2586         struct compressor_entry *ce;
2587         struct compressor *cp = NULL;
2588
2589         spin_lock(&compressor_list_lock);
2590         ce = find_comp_entry(type);
2591         if (ce) {
2592                 cp = ce->comp;
2593                 if (!try_module_get(cp->owner))
2594                         cp = NULL;
2595         }
2596         spin_unlock(&compressor_list_lock);
2597         return cp;
2598 }
2599
2600 /*
2601  * Miscelleneous stuff.
2602  */
2603
2604 static void
2605 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2606 {
2607         struct slcompress *vj = ppp->vj;
2608
2609         memset(st, 0, sizeof(*st));
2610         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2611         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2612         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2613         st->p.ppp_opackets = ppp->stats64.tx_packets;
2614         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2615         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2616         if (!vj)
2617                 return;
2618         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2619         st->vj.vjs_compressed = vj->sls_o_compressed;
2620         st->vj.vjs_searches = vj->sls_o_searches;
2621         st->vj.vjs_misses = vj->sls_o_misses;
2622         st->vj.vjs_errorin = vj->sls_i_error;
2623         st->vj.vjs_tossed = vj->sls_i_tossed;
2624         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2625         st->vj.vjs_compressedin = vj->sls_i_compressed;
2626 }
2627
2628 /*
2629  * Stuff for handling the lists of ppp units and channels
2630  * and for initialization.
2631  */
2632
2633 /*
2634  * Create a new ppp interface unit.  Fails if it can't allocate memory
2635  * or if there is already a unit with the requested number.
2636  * unit == -1 means allocate a new number.
2637  */
2638 static struct ppp *
2639 ppp_create_interface(struct net *net, int unit, int *retp)
2640 {
2641         struct ppp *ppp;
2642         struct ppp_net *pn;
2643         struct net_device *dev = NULL;
2644         int ret = -ENOMEM;
2645         int i;
2646
2647         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2648         if (!dev)
2649                 goto out1;
2650
2651         pn = ppp_pernet(net);
2652
2653         ppp = netdev_priv(dev);
2654         ppp->dev = dev;
2655         ppp->mru = PPP_MRU;
2656         init_ppp_file(&ppp->file, INTERFACE);
2657         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2658         for (i = 0; i < NUM_NP; ++i)
2659                 ppp->npmode[i] = NPMODE_PASS;
2660         INIT_LIST_HEAD(&ppp->channels);
2661         spin_lock_init(&ppp->rlock);
2662         spin_lock_init(&ppp->wlock);
2663 #ifdef CONFIG_PPP_MULTILINK
2664         ppp->minseq = -1;
2665         skb_queue_head_init(&ppp->mrq);
2666 #endif /* CONFIG_PPP_MULTILINK */
2667
2668         /*
2669          * drum roll: don't forget to set
2670          * the net device is belong to
2671          */
2672         dev_net_set(dev, net);
2673
2674         mutex_lock(&pn->all_ppp_mutex);
2675
2676         if (unit < 0) {
2677                 unit = unit_get(&pn->units_idr, ppp);
2678                 if (unit < 0) {
2679                         ret = unit;
2680                         goto out2;
2681                 }
2682         } else {
2683                 ret = -EEXIST;
2684                 if (unit_find(&pn->units_idr, unit))
2685                         goto out2; /* unit already exists */
2686                 /*
2687                  * if caller need a specified unit number
2688                  * lets try to satisfy him, otherwise --
2689                  * he should better ask us for new unit number
2690                  *
2691                  * NOTE: yes I know that returning EEXIST it's not
2692                  * fair but at least pppd will ask us to allocate
2693                  * new unit in this case so user is happy :)
2694                  */
2695                 unit = unit_set(&pn->units_idr, ppp, unit);
2696                 if (unit < 0)
2697                         goto out2;
2698         }
2699
2700         /* Initialize the new ppp unit */
2701         ppp->file.index = unit;
2702         sprintf(dev->name, "ppp%d", unit);
2703
2704         ret = register_netdev(dev);
2705         if (ret != 0) {
2706                 unit_put(&pn->units_idr, unit);
2707                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2708                            dev->name, ret);
2709                 goto out2;
2710         }
2711
2712         ppp->ppp_net = net;
2713
2714         atomic_inc(&ppp_unit_count);
2715         mutex_unlock(&pn->all_ppp_mutex);
2716
2717         *retp = 0;
2718         return ppp;
2719
2720 out2:
2721         mutex_unlock(&pn->all_ppp_mutex);
2722         free_netdev(dev);
2723 out1:
2724         *retp = ret;
2725         return NULL;
2726 }
2727
2728 /*
2729  * Initialize a ppp_file structure.
2730  */
2731 static void
2732 init_ppp_file(struct ppp_file *pf, int kind)
2733 {
2734         pf->kind = kind;
2735         skb_queue_head_init(&pf->xq);
2736         skb_queue_head_init(&pf->rq);
2737         atomic_set(&pf->refcnt, 1);
2738         init_waitqueue_head(&pf->rwait);
2739 }
2740
2741 /*
2742  * Take down a ppp interface unit - called when the owning file
2743  * (the one that created the unit) is closed or detached.
2744  */
2745 static void ppp_shutdown_interface(struct ppp *ppp)
2746 {
2747         struct ppp_net *pn;
2748
2749         pn = ppp_pernet(ppp->ppp_net);
2750         mutex_lock(&pn->all_ppp_mutex);
2751
2752         /* This will call dev_close() for us. */
2753         ppp_lock(ppp);
2754         if (!ppp->closing) {
2755                 ppp->closing = 1;
2756                 ppp_unlock(ppp);
2757                 unregister_netdev(ppp->dev);
2758                 unit_put(&pn->units_idr, ppp->file.index);
2759         } else
2760                 ppp_unlock(ppp);
2761
2762         ppp->file.dead = 1;
2763         ppp->owner = NULL;
2764         wake_up_interruptible(&ppp->file.rwait);
2765
2766         mutex_unlock(&pn->all_ppp_mutex);
2767 }
2768
2769 /*
2770  * Free the memory used by a ppp unit.  This is only called once
2771  * there are no channels connected to the unit and no file structs
2772  * that reference the unit.
2773  */
2774 static void ppp_destroy_interface(struct ppp *ppp)
2775 {
2776         atomic_dec(&ppp_unit_count);
2777
2778         if (!ppp->file.dead || ppp->n_channels) {
2779                 /* "can't happen" */
2780                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2781                            "but dead=%d n_channels=%d !\n",
2782                            ppp, ppp->file.dead, ppp->n_channels);
2783                 return;
2784         }
2785
2786         ppp_ccp_closed(ppp);
2787         if (ppp->vj) {
2788                 slhc_free(ppp->vj);
2789                 ppp->vj = NULL;
2790         }
2791         skb_queue_purge(&ppp->file.xq);
2792         skb_queue_purge(&ppp->file.rq);
2793 #ifdef CONFIG_PPP_MULTILINK
2794         skb_queue_purge(&ppp->mrq);
2795 #endif /* CONFIG_PPP_MULTILINK */
2796 #ifdef CONFIG_PPP_FILTER
2797         kfree(ppp->pass_filter);
2798         ppp->pass_filter = NULL;
2799         kfree(ppp->active_filter);
2800         ppp->active_filter = NULL;
2801 #endif /* CONFIG_PPP_FILTER */
2802
2803         kfree_skb(ppp->xmit_pending);
2804
2805         free_netdev(ppp->dev);
2806 }
2807
2808 /*
2809  * Locate an existing ppp unit.
2810  * The caller should have locked the all_ppp_mutex.
2811  */
2812 static struct ppp *
2813 ppp_find_unit(struct ppp_net *pn, int unit)
2814 {
2815         return unit_find(&pn->units_idr, unit);
2816 }
2817
2818 /*
2819  * Locate an existing ppp channel.
2820  * The caller should have locked the all_channels_lock.
2821  * First we look in the new_channels list, then in the
2822  * all_channels list.  If found in the new_channels list,
2823  * we move it to the all_channels list.  This is for speed
2824  * when we have a lot of channels in use.
2825  */
2826 static struct channel *
2827 ppp_find_channel(struct ppp_net *pn, int unit)
2828 {
2829         struct channel *pch;
2830
2831         list_for_each_entry(pch, &pn->new_channels, list) {
2832                 if (pch->file.index == unit) {
2833                         list_move(&pch->list, &pn->all_channels);
2834                         return pch;
2835                 }
2836         }
2837
2838         list_for_each_entry(pch, &pn->all_channels, list) {
2839                 if (pch->file.index == unit)
2840                         return pch;
2841         }
2842
2843         return NULL;
2844 }
2845
2846 /*
2847  * Connect a PPP channel to a PPP interface unit.
2848  */
2849 static int
2850 ppp_connect_channel(struct channel *pch, int unit)
2851 {
2852         struct ppp *ppp;
2853         struct ppp_net *pn;
2854         int ret = -ENXIO;
2855         int hdrlen;
2856
2857         pn = ppp_pernet(pch->chan_net);
2858
2859         mutex_lock(&pn->all_ppp_mutex);
2860         ppp = ppp_find_unit(pn, unit);
2861         if (!ppp)
2862                 goto out;
2863         write_lock_bh(&pch->upl);
2864         ret = -EINVAL;
2865         if (pch->ppp)
2866                 goto outl;
2867
2868         ppp_lock(ppp);
2869         if (pch->file.hdrlen > ppp->file.hdrlen)
2870                 ppp->file.hdrlen = pch->file.hdrlen;
2871         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2872         if (hdrlen > ppp->dev->hard_header_len)
2873                 ppp->dev->hard_header_len = hdrlen;
2874         list_add_tail(&pch->clist, &ppp->channels);
2875         ++ppp->n_channels;
2876         pch->ppp = ppp;
2877         atomic_inc(&ppp->file.refcnt);
2878         ppp_unlock(ppp);
2879         ret = 0;
2880
2881  outl:
2882         write_unlock_bh(&pch->upl);
2883  out:
2884         mutex_unlock(&pn->all_ppp_mutex);
2885         return ret;
2886 }
2887
2888 /*
2889  * Disconnect a channel from its ppp unit.
2890  */
2891 static int
2892 ppp_disconnect_channel(struct channel *pch)
2893 {
2894         struct ppp *ppp;
2895         int err = -EINVAL;
2896
2897         write_lock_bh(&pch->upl);
2898         ppp = pch->ppp;
2899         pch->ppp = NULL;
2900         write_unlock_bh(&pch->upl);
2901         if (ppp) {
2902                 /* remove it from the ppp unit's list */
2903                 ppp_lock(ppp);
2904                 list_del(&pch->clist);
2905                 if (--ppp->n_channels == 0)
2906                         wake_up_interruptible(&ppp->file.rwait);
2907                 ppp_unlock(ppp);
2908                 if (atomic_dec_and_test(&ppp->file.refcnt))
2909                         ppp_destroy_interface(ppp);
2910                 err = 0;
2911         }
2912         return err;
2913 }
2914
2915 /*
2916  * Free up the resources used by a ppp channel.
2917  */
2918 static void ppp_destroy_channel(struct channel *pch)
2919 {
2920         atomic_dec(&channel_count);
2921
2922         if (!pch->file.dead) {
2923                 /* "can't happen" */
2924                 pr_err("ppp: destroying undead channel %p !\n", pch);
2925                 return;
2926         }
2927         skb_queue_purge(&pch->file.xq);
2928         skb_queue_purge(&pch->file.rq);
2929         kfree(pch);
2930 }
2931
2932 static void __exit ppp_cleanup(void)
2933 {
2934         /* should never happen */
2935         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2936                 pr_err("PPP: removing module but units remain!\n");
2937         unregister_chrdev(PPP_MAJOR, "ppp");
2938         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2939         class_destroy(ppp_class);
2940         unregister_pernet_device(&ppp_net_ops);
2941 }
2942
2943 /*
2944  * Units handling. Caller must protect concurrent access
2945  * by holding all_ppp_mutex
2946  */
2947
2948 static int __unit_alloc(struct idr *p, void *ptr, int n)
2949 {
2950         int unit, err;
2951
2952 again:
2953         if (!idr_pre_get(p, GFP_KERNEL)) {
2954                 pr_err("PPP: No free memory for idr\n");
2955                 return -ENOMEM;
2956         }
2957
2958         err = idr_get_new_above(p, ptr, n, &unit);
2959         if (err < 0) {
2960                 if (err == -EAGAIN)
2961                         goto again;
2962                 return err;
2963         }
2964
2965         return unit;
2966 }
2967
2968 /* associate pointer with specified number */
2969 static int unit_set(struct idr *p, void *ptr, int n)
2970 {
2971         int unit;
2972
2973         unit = __unit_alloc(p, ptr, n);
2974         if (unit < 0)
2975                 return unit;
2976         else if (unit != n) {
2977                 idr_remove(p, unit);
2978                 return -EINVAL;
2979         }
2980
2981         return unit;
2982 }
2983
2984 /* get new free unit number and associate pointer with it */
2985 static int unit_get(struct idr *p, void *ptr)
2986 {
2987         return __unit_alloc(p, ptr, 0);
2988 }
2989
2990 /* put unit number back to a pool */
2991 static void unit_put(struct idr *p, int n)
2992 {
2993         idr_remove(p, n);
2994 }
2995
2996 /* get pointer associated with the number */
2997 static void *unit_find(struct idr *p, int n)
2998 {
2999         return idr_find(p, n);
3000 }
3001
3002 /* Module/initialization stuff */
3003
3004 module_init(ppp_init);
3005 module_exit(ppp_cleanup);
3006
3007 EXPORT_SYMBOL(ppp_register_net_channel);
3008 EXPORT_SYMBOL(ppp_register_channel);
3009 EXPORT_SYMBOL(ppp_unregister_channel);
3010 EXPORT_SYMBOL(ppp_channel_index);
3011 EXPORT_SYMBOL(ppp_unit_number);
3012 EXPORT_SYMBOL(ppp_dev_name);
3013 EXPORT_SYMBOL(ppp_input);
3014 EXPORT_SYMBOL(ppp_input_error);
3015 EXPORT_SYMBOL(ppp_output_wakeup);
3016 EXPORT_SYMBOL(ppp_register_compressor);
3017 EXPORT_SYMBOL(ppp_unregister_compressor);
3018 MODULE_LICENSE("GPL");
3019 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3020 MODULE_ALIAS("devname:ppp");