drivers/net/pppol2tp.c

   1 /*****************************************************************************
   2  * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
   3  *
   4  * PPPoX    --- Generic PPP encapsulation socket family
   5  * PPPoL2TP --- PPP over L2TP (RFC 2661)
   6  *
   7  * Version:     1.0.0
   8  *
   9  * Authors:     Martijn van Oosterhout <kleptog@svana.org>
  10  *              James Chapman (jchapman@katalix.com)
  11  * Contributors:
  12  *              Michal Ostrowski <mostrows@speakeasy.net>
  13  *              Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
  14  *              David S. Miller (davem@redhat.com)
  15  *
  16  * License:
  17  *              This program is free software; you can redistribute it and/or
  18  *              modify it under the terms of the GNU General Public License
  19  *              as published by the Free Software Foundation; either version
  20  *              2 of the License, or (at your option) any later version.
  21  *
  22  */
  23
  24 /* This driver handles only L2TP data frames; control frames are handled by a
  25  * userspace application.
  26  *
  27  * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
  28  * attaches it to a bound UDP socket with local tunnel_id / session_id and
  29  * peer tunnel_id / session_id set. Data can then be sent or received using
  30  * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
  31  * can be read or modified using ioctl() or [gs]etsockopt() calls.
  32  *
  33  * When a PPPoL2TP socket is connected with local and peer session_id values
  34  * zero, the socket is treated as a special tunnel management socket.
  35  *
  36  * Here's example userspace code to create a socket for sending/receiving data
  37  * over an L2TP session:-
  38  *
  39  *      struct sockaddr_pppol2tp sax;
  40  *      int fd;
  41  *      int session_fd;
  42  *
  43  *      fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
  44  *
  45  *      sax.sa_family = AF_PPPOX;
  46  *      sax.sa_protocol = PX_PROTO_OL2TP;
  47  *      sax.pppol2tp.fd = tunnel_fd;    // bound UDP socket
  48  *      sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
  49  *      sax.pppol2tp.addr.sin_port = addr->sin_port;
  50  *      sax.pppol2tp.addr.sin_family = AF_INET;
  51  *      sax.pppol2tp.s_tunnel  = tunnel_id;
  52  *      sax.pppol2tp.s_session = session_id;
  53  *      sax.pppol2tp.d_tunnel  = peer_tunnel_id;
  54  *      sax.pppol2tp.d_session = peer_session_id;
  55  *
  56  *      session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
  57  *
  58  * A pppd plugin that allows PPP traffic to be carried over L2TP using
  59  * this driver is available from the OpenL2TP project at
  60  * http://openl2tp.sourceforge.net.
  61  */
  62
  63 #include <linux/module.h>
  64 #include <linux/string.h>
  65 #include <linux/list.h>
  66 #include <asm/uaccess.h>
  67
  68 #include <linux/kernel.h>
  69 #include <linux/spinlock.h>
  70 #include <linux/kthread.h>
  71 #include <linux/sched.h>
  72 #include <linux/slab.h>
  73 #include <linux/errno.h>
  74 #include <linux/jiffies.h>
  75
  76 #include <linux/netdevice.h>
  77 #include <linux/net.h>
  78 #include <linux/inetdevice.h>
  79 #include <linux/skbuff.h>
  80 #include <linux/init.h>
  81 #include <linux/ip.h>
  82 #include <linux/udp.h>
  83 #include <linux/if_pppox.h>
  84 #include <linux/if_pppol2tp.h>
  85 #include <net/sock.h>
  86 #include <linux/ppp_channel.h>
  87 #include <linux/ppp_defs.h>
  88 #include <linux/if_ppp.h>
  89 #include <linux/file.h>
  90 #include <linux/hash.h>
  91 #include <linux/sort.h>
  92 #include <linux/proc_fs.h>
  93 #include <linux/nsproxy.h>
  94 #include <net/net_namespace.h>
  95 #include <net/netns/generic.h>
  96 #include <net/dst.h>
  97 #include <net/ip.h>
  98 #include <net/udp.h>
  99 #include <net/xfrm.h>
 100
 101 #include <asm/byteorder.h>
 102 #include <asm/atomic.h>
 103
 104
 105 #define PPPOL2TP_DRV_VERSION    "V1.0"
 106
 107 /* L2TP header constants */
 108 #define L2TP_HDRFLAG_T     0x8000
 109 #define L2TP_HDRFLAG_L     0x4000
 110 #define L2TP_HDRFLAG_S     0x0800
 111 #define L2TP_HDRFLAG_O     0x0200
 112 #define L2TP_HDRFLAG_P     0x0100
 113
 114 #define L2TP_HDR_VER_MASK  0x000F
 115 #define L2TP_HDR_VER       0x0002
 116
 117 /* Space for UDP, L2TP and PPP headers */
 118 #define PPPOL2TP_HEADER_OVERHEAD        40
 119
 120 /* Just some random numbers */
 121 #define L2TP_TUNNEL_MAGIC       0x42114DDA
 122 #define L2TP_SESSION_MAGIC      0x0C04EB7D
 123
 124 #define PPPOL2TP_HASH_BITS      4
 125 #define PPPOL2TP_HASH_SIZE      (1 << PPPOL2TP_HASH_BITS)
 126
 127 /* Default trace flags */
 128 #define PPPOL2TP_DEFAULT_DEBUG_FLAGS    0
 129
 130 #define PRINTK(_mask, _type, _lvl, _fmt, args...)                       \
 131         do {                                                            \
 132                 if ((_mask) & (_type))                                  \
 133                         printk(_lvl "PPPOL2TP: " _fmt, ##args);         \
 134         } while(0)
 135
 136 /* Number of bytes to build transmit L2TP headers.
 137  * Unfortunately the size is different depending on whether sequence numbers
 138  * are enabled.
 139  */
 140 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ              10
 141 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ            6
 142
 143 struct pppol2tp_tunnel;
 144
 145 /* Describes a session. It is the sk_user_data field in the PPPoL2TP
 146  * socket. Contains information to determine incoming packets and transmit
 147  * outgoing ones.
 148  */
 149 struct pppol2tp_session
 150 {
 151         int                     magic;          /* should be
 152                                                  * L2TP_SESSION_MAGIC */
 153         int                     owner;          /* pid that opened the socket */
 154
 155         struct sock             *sock;          /* Pointer to the session
 156                                                  * PPPoX socket */
 157         struct sock             *tunnel_sock;   /* Pointer to the tunnel UDP
 158                                                  * socket */
 159
 160         struct pppol2tp_addr    tunnel_addr;    /* Description of tunnel */
 161
 162         struct pppol2tp_tunnel  *tunnel;        /* back pointer to tunnel
 163                                                  * context */
 164
 165         char                    name[20];       /* "sess xxxxx/yyyyy", where
 166                                                  * x=tunnel_id, y=session_id */
 167         int                     mtu;
 168         int                     mru;
 169         int                     flags;          /* accessed by PPPIOCGFLAGS.
 170                                                  * Unused. */
 171         unsigned                recv_seq:1;     /* expect receive packets with
 172                                                  * sequence numbers? */
 173         unsigned                send_seq:1;     /* send packets with sequence
 174                                                  * numbers? */
 175         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
 176                                                  * sequence numbers under
 177                                                  * control of LNS. */
 178         int                     debug;          /* bitmask of debug message
 179                                                  * categories */
 180         int                     reorder_timeout; /* configured reorder timeout
 181                                                   * (in jiffies) */
 182         u16                     nr;             /* session NR state (receive) */
 183         u16                     ns;             /* session NR state (send) */
 184         struct sk_buff_head     reorder_q;      /* receive reorder queue */
 185         struct pppol2tp_ioc_stats stats;
 186         struct hlist_node       hlist;          /* Hash list node */
 187 };
 188
 189 /* The sk_user_data field of the tunnel's UDP socket. It contains info to track
 190  * all the associated sessions so incoming packets can be sorted out
 191  */
 192 struct pppol2tp_tunnel
 193 {
 194         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 195         rwlock_t                hlist_lock;     /* protect session_hlist */
 196         struct hlist_head       session_hlist[PPPOL2TP_HASH_SIZE];
 197                                                 /* hashed list of sessions,
 198                                                  * hashed by id */
 199         int                     debug;          /* bitmask of debug message
 200                                                  * categories */
 201         char                    name[12];       /* "tunl xxxxx" */
 202         struct pppol2tp_ioc_stats stats;
 203
 204         void (*old_sk_destruct)(struct sock *);
 205
 206         struct sock             *sock;          /* Parent socket */
 207         struct list_head        list;           /* Keep a list of all open
 208                                                  * prepared sockets */
 209         struct net              *pppol2tp_net;  /* the net we belong to */
 210
 211         atomic_t                ref_count;
 212 };
 213
 214 /* Private data stored for received packets in the skb.
 215  */
 216 struct pppol2tp_skb_cb {
 217         u16                     ns;
 218         u16                     nr;
 219         u16                     has_seq;
 220         u16                     length;
 221         unsigned long           expires;
 222 };
 223
 224 #define PPPOL2TP_SKB_CB(skb)    ((struct pppol2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
 225
 226 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
 227 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel);
 228
 229 static atomic_t pppol2tp_tunnel_count;
 230 static atomic_t pppol2tp_session_count;
 231 static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
 232 static const struct proto_ops pppol2tp_ops;
 233
 234 /* per-net private data for this module */
 235 static int pppol2tp_net_id;
 236 struct pppol2tp_net {
 237         struct list_head pppol2tp_tunnel_list;
 238         rwlock_t pppol2tp_tunnel_list_lock;
 239 };
 240
 241 static inline struct pppol2tp_net *pppol2tp_pernet(struct net *net)
 242 {
 243         BUG_ON(!net);
 244
 245         return net_generic(net, pppol2tp_net_id);
 246 }
 247
 248 /* Helpers to obtain tunnel/session contexts from sockets.
 249  */
 250 static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk)
 251 {
 252         struct pppol2tp_session *session;
 253
 254         if (sk == NULL)
 255                 return NULL;
 256
 257         sock_hold(sk);
 258         session = (struct pppol2tp_session *)(sk->sk_user_data);
 259         if (session == NULL) {
 260                 sock_put(sk);
 261                 goto out;
 262         }
 263
 264         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 265 out:
 266         return session;
 267 }
 268
 269 static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk)
 270 {
 271         struct pppol2tp_tunnel *tunnel;
 272
 273         if (sk == NULL)
 274                 return NULL;
 275
 276         sock_hold(sk);
 277         tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data);
 278         if (tunnel == NULL) {
 279                 sock_put(sk);
 280                 goto out;
 281         }
 282
 283         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 284 out:
 285         return tunnel;
 286 }
 287
 288 /* Tunnel reference counts. Incremented per session that is added to
 289  * the tunnel.
 290  */
 291 static inline void pppol2tp_tunnel_inc_refcount(struct pppol2tp_tunnel *tunnel)
 292 {
 293         atomic_inc(&tunnel->ref_count);
 294 }
 295
 296 static inline void pppol2tp_tunnel_dec_refcount(struct pppol2tp_tunnel *tunnel)
 297 {
 298         if (atomic_dec_and_test(&tunnel->ref_count))
 299                 pppol2tp_tunnel_free(tunnel);
 300 }
 301
 302 /* Session hash list.
 303  * The session_id SHOULD be random according to RFC2661, but several
 304  * L2TP implementations (Cisco and Microsoft) use incrementing
 305  * session_ids.  So we do a real hash on the session_id, rather than a
 306  * simple bitmask.
 307  */
 308 static inline struct hlist_head *
 309 pppol2tp_session_id_hash(struct pppol2tp_tunnel *tunnel, u16 session_id)
 310 {
 311         unsigned long hash_val = (unsigned long) session_id;
 312         return &tunnel->session_hlist[hash_long(hash_val, PPPOL2TP_HASH_BITS)];
 313 }
 314
 315 /* Lookup a session by id
 316  */
 317 static struct pppol2tp_session *
 318 pppol2tp_session_find(struct pppol2tp_tunnel *tunnel, u16 session_id)
 319 {
 320         struct hlist_head *session_list =
 321                 pppol2tp_session_id_hash(tunnel, session_id);
 322         struct pppol2tp_session *session;
 323         struct hlist_node *walk;
 324
 325         read_lock_bh(&tunnel->hlist_lock);
 326         hlist_for_each_entry(session, walk, session_list, hlist) {
 327                 if (session->tunnel_addr.s_session == session_id) {
 328                         read_unlock_bh(&tunnel->hlist_lock);
 329                         return session;
 330                 }
 331         }
 332         read_unlock_bh(&tunnel->hlist_lock);
 333
 334         return NULL;
 335 }
 336
 337 /* Lookup a tunnel by id
 338  */
 339 static struct pppol2tp_tunnel *pppol2tp_tunnel_find(struct net *net, u16 tunnel_id)
 340 {
 341         struct pppol2tp_tunnel *tunnel;
 342         struct pppol2tp_net *pn = pppol2tp_pernet(net);
 343
 344         read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
 345         list_for_each_entry(tunnel, &pn->pppol2tp_tunnel_list, list) {
 346                 if (tunnel->stats.tunnel_id == tunnel_id) {
 347                         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
 348                         return tunnel;
 349                 }
 350         }
 351         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
 352
 353         return NULL;
 354 }
 355
 356 /*****************************************************************************
 357  * Receive data handling
 358  *****************************************************************************/
 359
 360 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
 361  * number.
 362  */
 363 static void pppol2tp_recv_queue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 364 {
 365         struct sk_buff *skbp;
 366         struct sk_buff *tmp;
 367         u16 ns = PPPOL2TP_SKB_CB(skb)->ns;
 368
 369         spin_lock_bh(&session->reorder_q.lock);
 370         skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
 371                 if (PPPOL2TP_SKB_CB(skbp)->ns > ns) {
 372                         __skb_queue_before(&session->reorder_q, skbp, skb);
 373                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 374                                "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
 375                                session->name, ns, PPPOL2TP_SKB_CB(skbp)->ns,
 376                                skb_queue_len(&session->reorder_q));
 377                         session->stats.rx_oos_packets++;
 378                         goto out;
 379                 }
 380         }
 381
 382         __skb_queue_tail(&session->reorder_q, skb);
 383
 384 out:
 385         spin_unlock_bh(&session->reorder_q.lock);
 386 }
 387
 388 /* Dequeue a single skb.
 389  */
 390 static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 391 {
 392         struct pppol2tp_tunnel *tunnel = session->tunnel;
 393         int length = PPPOL2TP_SKB_CB(skb)->length;
 394         struct sock *session_sock = NULL;
 395
 396         /* We're about to requeue the skb, so return resources
 397          * to its current owner (a socket receive buffer).
 398          */
 399         skb_orphan(skb);
 400
 401         tunnel->stats.rx_packets++;
 402         tunnel->stats.rx_bytes += length;
 403         session->stats.rx_packets++;
 404         session->stats.rx_bytes += length;
 405
 406         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 407                 /* Bump our Nr */
 408                 session->nr++;
 409                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 410                        "%s: updated nr to %hu\n", session->name, session->nr);
 411         }
 412
 413         /* If the socket is bound, send it in to PPP's input queue. Otherwise
 414          * queue it on the session socket.
 415          */
 416         session_sock = session->sock;
 417         if (session_sock->sk_state & PPPOX_BOUND) {
 418                 struct pppox_sock *po;
 419                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 420                        "%s: recv %d byte data frame, passing to ppp\n",
 421                        session->name, length);
 422
 423                 /* We need to forget all info related to the L2TP packet
 424                  * gathered in the skb as we are going to reuse the same
 425                  * skb for the inner packet.
 426                  * Namely we need to:
 427                  * - reset xfrm (IPSec) information as it applies to
 428                  *   the outer L2TP packet and not to the inner one
 429                  * - release the dst to force a route lookup on the inner
 430                  *   IP packet since skb->dst currently points to the dst
 431                  *   of the UDP tunnel
 432                  * - reset netfilter information as it doesn't apply
 433                  *   to the inner packet either
 434                  */
 435                 secpath_reset(skb);
 436                 skb_dst_drop(skb);
 437                 nf_reset(skb);
 438
 439                 po = pppox_sk(session_sock);
 440                 ppp_input(&po->chan, skb);
 441         } else {
 442                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 443                        "%s: socket not bound\n", session->name);
 444
 445                 /* Not bound. Nothing we can do, so discard. */
 446                 session->stats.rx_errors++;
 447                 kfree_skb(skb);
 448         }
 449
 450         sock_put(session->sock);
 451 }
 452
 453 /* Dequeue skbs from the session's reorder_q, subject to packet order.
 454  * Skbs that have been in the queue for too long are simply discarded.
 455  */
 456 static void pppol2tp_recv_dequeue(struct pppol2tp_session *session)
 457 {
 458         struct sk_buff *skb;
 459         struct sk_buff *tmp;
 460
 461         /* If the pkt at the head of the queue has the nr that we
 462          * expect to send up next, dequeue it and any other
 463          * in-sequence packets behind it.
 464          */
 465         spin_lock_bh(&session->reorder_q.lock);
 466         skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
 467                 if (time_after(jiffies, PPPOL2TP_SKB_CB(skb)->expires)) {
 468                         session->stats.rx_seq_discards++;
 469                         session->stats.rx_errors++;
 470                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 471                                "%s: oos pkt %hu len %d discarded (too old), "
 472                                "waiting for %hu, reorder_q_len=%d\n",
 473                                session->name, PPPOL2TP_SKB_CB(skb)->ns,
 474                                PPPOL2TP_SKB_CB(skb)->length, session->nr,
 475                                skb_queue_len(&session->reorder_q));
 476                         __skb_unlink(skb, &session->reorder_q);
 477                         kfree_skb(skb);
 478                         sock_put(session->sock);
 479                         continue;
 480                 }
 481
 482                 if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 483                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 484                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 485                                        "%s: holding oos pkt %hu len %d, "
 486                                        "waiting for %hu, reorder_q_len=%d\n",
 487                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 488                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 489                                        skb_queue_len(&session->reorder_q));
 490                                 goto out;
 491                         }
 492                 }
 493                 __skb_unlink(skb, &session->reorder_q);
 494
 495                 /* Process the skb. We release the queue lock while we
 496                  * do so to let other contexts process the queue.
 497                  */
 498                 spin_unlock_bh(&session->reorder_q.lock);
 499                 pppol2tp_recv_dequeue_skb(session, skb);
 500                 spin_lock_bh(&session->reorder_q.lock);
 501         }
 502
 503 out:
 504         spin_unlock_bh(&session->reorder_q.lock);
 505 }
 506
 507 static inline int pppol2tp_verify_udp_checksum(struct sock *sk,
 508                                                struct sk_buff *skb)
 509 {
 510         struct udphdr *uh = udp_hdr(skb);
 511         u16 ulen = ntohs(uh->len);
 512         struct inet_sock *inet;
 513         __wsum psum;
 514
 515         if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
 516                 return 0;
 517
 518         inet = inet_sk(sk);
 519         psum = csum_tcpudp_nofold(inet->saddr, inet->daddr, ulen,
 520                                   IPPROTO_UDP, 0);
 521
 522         if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
 523             !csum_fold(csum_add(psum, skb->csum)))
 524                 return 0;
 525
 526         skb->csum = psum;
 527
 528         return __skb_checksum_complete(skb);
 529 }
 530
 531 /* Internal receive frame. Do the real work of receiving an L2TP data frame
 532  * here. The skb is not on a list when we get here.
 533  * Returns 0 if the packet was a data packet and was successfully passed on.
 534  * Returns 1 if the packet was not a good data packet and could not be
 535  * forwarded.  All such packets are passed up to userspace to deal with.
 536  */
 537 static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
 538 {
 539         struct pppol2tp_session *session = NULL;
 540         struct pppol2tp_tunnel *tunnel;
 541         unsigned char *ptr, *optr;
 542         u16 hdrflags;
 543         u16 tunnel_id, session_id;
 544         int length;
 545         int offset;
 546
 547         tunnel = pppol2tp_sock_to_tunnel(sock);
 548         if (tunnel == NULL)
 549                 goto no_tunnel;
 550
 551         if (tunnel->sock && pppol2tp_verify_udp_checksum(tunnel->sock, skb))
 552                 goto discard_bad_csum;
 553
 554         /* UDP always verifies the packet length. */
 555         __skb_pull(skb, sizeof(struct udphdr));
 556
 557         /* Short packet? */
 558         if (!pskb_may_pull(skb, 12)) {
 559                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 560                        "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
 561                 goto error;
 562         }
 563
 564         /* Point to L2TP header */
 565         optr = ptr = skb->data;
 566
 567         /* Get L2TP header flags */
 568         hdrflags = ntohs(*(__be16*)ptr);
 569
 570         /* Trace packet contents, if enabled */
 571         if (tunnel->debug & PPPOL2TP_MSG_DATA) {
 572                 length = min(16u, skb->len);
 573                 if (!pskb_may_pull(skb, length))
 574                         goto error;
 575
 576                 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
 577
 578                 offset = 0;
 579                 do {
 580                         printk(" %02X", ptr[offset]);
 581                 } while (++offset < length);
 582
 583                 printk("\n");
 584         }
 585
 586         /* Get length of L2TP packet */
 587         length = skb->len;
 588
 589         /* If type is control packet, it is handled by userspace. */
 590         if (hdrflags & L2TP_HDRFLAG_T) {
 591                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 592                        "%s: recv control packet, len=%d\n", tunnel->name, length);
 593                 goto error;
 594         }
 595
 596         /* Skip flags */
 597         ptr += 2;
 598
 599         /* If length is present, skip it */
 600         if (hdrflags & L2TP_HDRFLAG_L)
 601                 ptr += 2;
 602
 603         /* Extract tunnel and session ID */
 604         tunnel_id = ntohs(*(__be16 *) ptr);
 605         ptr += 2;
 606         session_id = ntohs(*(__be16 *) ptr);
 607         ptr += 2;
 608
 609         /* Find the session context */
 610         session = pppol2tp_session_find(tunnel, session_id);
 611         if (!session) {
 612                 /* Not found? Pass to userspace to deal with */
 613                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 614                        "%s: no socket found (%hu/%hu). Passing up.\n",
 615                        tunnel->name, tunnel_id, session_id);
 616                 goto error;
 617         }
 618         sock_hold(session->sock);
 619
 620         /* The ref count on the socket was increased by the above call since
 621          * we now hold a pointer to the session. Take care to do sock_put()
 622          * when exiting this function from now on...
 623          */
 624
 625         /* Handle the optional sequence numbers.  If we are the LAC,
 626          * enable/disable sequence numbers under the control of the LNS.  If
 627          * no sequence numbers present but we were expecting them, discard
 628          * frame.
 629          */
 630         if (hdrflags & L2TP_HDRFLAG_S) {
 631                 u16 ns, nr;
 632                 ns = ntohs(*(__be16 *) ptr);
 633                 ptr += 2;
 634                 nr = ntohs(*(__be16 *) ptr);
 635                 ptr += 2;
 636
 637                 /* Received a packet with sequence numbers. If we're the LNS,
 638                  * check if we sre sending sequence numbers and if not,
 639                  * configure it so.
 640                  */
 641                 if ((!session->lns_mode) && (!session->send_seq)) {
 642                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 643                                "%s: requested to enable seq numbers by LNS\n",
 644                                session->name);
 645                         session->send_seq = -1;
 646                 }
 647
 648                 /* Store L2TP info in the skb */
 649                 PPPOL2TP_SKB_CB(skb)->ns = ns;
 650                 PPPOL2TP_SKB_CB(skb)->nr = nr;
 651                 PPPOL2TP_SKB_CB(skb)->has_seq = 1;
 652
 653                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 654                        "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n",
 655                        session->name, ns, nr, session->nr);
 656         } else {
 657                 /* No sequence numbers.
 658                  * If user has configured mandatory sequence numbers, discard.
 659                  */
 660                 if (session->recv_seq) {
 661                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 662                                "%s: recv data has no seq numbers when required. "
 663                                "Discarding\n", session->name);
 664                         session->stats.rx_seq_discards++;
 665                         goto discard;
 666                 }
 667
 668                 /* If we're the LAC and we're sending sequence numbers, the
 669                  * LNS has requested that we no longer send sequence numbers.
 670                  * If we're the LNS and we're sending sequence numbers, the
 671                  * LAC is broken. Discard the frame.
 672                  */
 673                 if ((!session->lns_mode) && (session->send_seq)) {
 674                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 675                                "%s: requested to disable seq numbers by LNS\n",
 676                                session->name);
 677                         session->send_seq = 0;
 678                 } else if (session->send_seq) {
 679                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 680                                "%s: recv data has no seq numbers when required. "
 681                                "Discarding\n", session->name);
 682                         session->stats.rx_seq_discards++;
 683                         goto discard;
 684                 }
 685
 686                 /* Store L2TP info in the skb */
 687                 PPPOL2TP_SKB_CB(skb)->has_seq = 0;
 688         }
 689
 690         /* If offset bit set, skip it. */
 691         if (hdrflags & L2TP_HDRFLAG_O) {
 692                 offset = ntohs(*(__be16 *)ptr);
 693                 ptr += 2 + offset;
 694         }
 695
 696         offset = ptr - optr;
 697         if (!pskb_may_pull(skb, offset))
 698                 goto discard;
 699
 700         __skb_pull(skb, offset);
 701
 702         /* Skip PPP header, if present.  In testing, Microsoft L2TP clients
 703          * don't send the PPP header (PPP header compression enabled), but
 704          * other clients can include the header. So we cope with both cases
 705          * here. The PPP header is always FF03 when using L2TP.
 706          *
 707          * Note that skb->data[] isn't dereferenced from a u16 ptr here since
 708          * the field may be unaligned.
 709          */
 710         if (!pskb_may_pull(skb, 2))
 711                 goto discard;
 712
 713         if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
 714                 skb_pull(skb, 2);
 715
 716         /* Prepare skb for adding to the session's reorder_q.  Hold
 717          * packets for max reorder_timeout or 1 second if not
 718          * reordering.
 719          */
 720         PPPOL2TP_SKB_CB(skb)->length = length;
 721         PPPOL2TP_SKB_CB(skb)->expires = jiffies +
 722                 (session->reorder_timeout ? session->reorder_timeout : HZ);
 723
 724         /* Add packet to the session's receive queue. Reordering is done here, if
 725          * enabled. Saved L2TP protocol info is stored in skb->sb[].
 726          */
 727         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 728                 if (session->reorder_timeout != 0) {
 729                         /* Packet reordering enabled. Add skb to session's
 730                          * reorder queue, in order of ns.
 731                          */
 732                         pppol2tp_recv_queue_skb(session, skb);
 733                 } else {
 734                         /* Packet reordering disabled. Discard out-of-sequence
 735                          * packets
 736                          */
 737                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 738                                 session->stats.rx_seq_discards++;
 739                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 740                                        "%s: oos pkt %hu len %d discarded, "
 741                                        "waiting for %hu, reorder_q_len=%d\n",
 742                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 743                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 744                                        skb_queue_len(&session->reorder_q));
 745                                 goto discard;
 746                         }
 747                         skb_queue_tail(&session->reorder_q, skb);
 748                 }
 749         } else {
 750                 /* No sequence numbers. Add the skb to the tail of the
 751                  * reorder queue. This ensures that it will be
 752                  * delivered after all previous sequenced skbs.
 753                  */
 754                 skb_queue_tail(&session->reorder_q, skb);
 755         }
 756
 757         /* Try to dequeue as many skbs from reorder_q as we can. */
 758         pppol2tp_recv_dequeue(session);
 759
 760         return 0;
 761
 762 discard:
 763         session->stats.rx_errors++;
 764         kfree_skb(skb);
 765         sock_put(session->sock);
 766         sock_put(sock);
 767
 768         return 0;
 769
 770 discard_bad_csum:
 771         LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
 772         UDP_INC_STATS_USER(&init_net, UDP_MIB_INERRORS, 0);
 773         tunnel->stats.rx_errors++;
 774         kfree_skb(skb);
 775
 776         return 0;
 777
 778 error:
 779         /* Put UDP header back */
 780         __skb_push(skb, sizeof(struct udphdr));
 781         sock_put(sock);
 782
 783 no_tunnel:
 784         return 1;
 785 }
 786
 787 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
 788  * Return codes:
 789  * 0 : success.
 790  * <0: error
 791  * >0: skb should be passed up to userspace as UDP.
 792  */
 793 static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 794 {
 795         struct pppol2tp_tunnel *tunnel;
 796
 797         tunnel = pppol2tp_sock_to_tunnel(sk);
 798         if (tunnel == NULL)
 799                 goto pass_up;
 800
 801         PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 802                "%s: received %d bytes\n", tunnel->name, skb->len);
 803
 804         if (pppol2tp_recv_core(sk, skb))
 805                 goto pass_up_put;
 806
 807         sock_put(sk);
 808         return 0;
 809
 810 pass_up_put:
 811         sock_put(sk);
 812 pass_up:
 813         return 1;
 814 }
 815
 816 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
 817  */
 818 static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
 819                             struct msghdr *msg, size_t len,
 820                             int flags)
 821 {
 822         int err;
 823         struct sk_buff *skb;
 824         struct sock *sk = sock->sk;
 825
 826         err = -EIO;
 827         if (sk->sk_state & PPPOX_BOUND)
 828                 goto end;
 829
 830         msg->msg_namelen = 0;
 831
 832         err = 0;
 833         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 834                                 flags & MSG_DONTWAIT, &err);
 835         if (!skb)
 836                 goto end;
 837
 838         if (len > skb->len)
 839                 len = skb->len;
 840         else if (len < skb->len)
 841                 msg->msg_flags |= MSG_TRUNC;
 842
 843         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
 844         if (likely(err == 0))
 845                 err = len;
 846
 847         kfree_skb(skb);
 848 end:
 849         return err;
 850 }
 851
 852 /************************************************************************
 853  * Transmit handling
 854  ***********************************************************************/
 855
 856 /* Tell how big L2TP headers are for a particular session. This
 857  * depends on whether sequence numbers are being used.
 858  */
 859 static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session)
 860 {
 861         if (session->send_seq)
 862                 return PPPOL2TP_L2TP_HDR_SIZE_SEQ;
 863
 864         return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
 865 }
 866
 867 /* Build an L2TP header for the session into the buffer provided.
 868  */
 869 static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session,
 870                                        void *buf)
 871 {
 872         __be16 *bufp = buf;
 873         u16 flags = L2TP_HDR_VER;
 874
 875         if (session->send_seq)
 876                 flags |= L2TP_HDRFLAG_S;
 877
 878         /* Setup L2TP header.
 879          * FIXME: Can this ever be unaligned? Is direct dereferencing of
 880          * 16-bit header fields safe here for all architectures?
 881          */
 882         *bufp++ = htons(flags);
 883         *bufp++ = htons(session->tunnel_addr.d_tunnel);
 884         *bufp++ = htons(session->tunnel_addr.d_session);
 885         if (session->send_seq) {
 886                 *bufp++ = htons(session->ns);
 887                 *bufp++ = 0;
 888                 session->ns++;
 889                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 890                        "%s: updated ns to %hu\n", session->name, session->ns);
 891         }
 892 }
 893
 894 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
 895  * when a user application does a sendmsg() on the session socket. L2TP and
 896  * PPP headers must be inserted into the user's data.
 897  */
 898 static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
 899                             size_t total_len)
 900 {
 901         static const unsigned char ppph[2] = { 0xff, 0x03 };
 902         struct sock *sk = sock->sk;
 903         struct inet_sock *inet;
 904         __wsum csum;
 905         struct sk_buff *skb;
 906         int error;
 907         int hdr_len;
 908         struct pppol2tp_session *session;
 909         struct pppol2tp_tunnel *tunnel;
 910         struct udphdr *uh;
 911         unsigned int len;
 912         struct sock *sk_tun;
 913         u16 udp_len;
 914
 915         error = -ENOTCONN;
 916         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 917                 goto error;
 918
 919         /* Get session and tunnel contexts */
 920         error = -EBADF;
 921         session = pppol2tp_sock_to_session(sk);
 922         if (session == NULL)
 923                 goto error;
 924
 925         sk_tun = session->tunnel_sock;
 926         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
 927         if (tunnel == NULL)
 928                 goto error_put_sess;
 929
 930         /* What header length is configured for this session? */
 931         hdr_len = pppol2tp_l2tp_header_len(session);
 932
 933         /* Allocate a socket buffer */
 934         error = -ENOMEM;
 935         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
 936                            sizeof(struct udphdr) + hdr_len +
 937                            sizeof(ppph) + total_len,
 938                            0, GFP_KERNEL);
 939         if (!skb)
 940                 goto error_put_sess_tun;
 941
 942         /* Reserve space for headers. */
 943         skb_reserve(skb, NET_SKB_PAD);
 944         skb_reset_network_header(skb);
 945         skb_reserve(skb, sizeof(struct iphdr));
 946         skb_reset_transport_header(skb);
 947
 948         /* Build UDP header */
 949         inet = inet_sk(sk_tun);
 950         udp_len = hdr_len + sizeof(ppph) + total_len;
 951         uh = (struct udphdr *) skb->data;
 952         uh->source = inet->sport;
 953         uh->dest = inet->dport;
 954         uh->len = htons(udp_len);
 955         uh->check = 0;
 956         skb_put(skb, sizeof(struct udphdr));
 957
 958         /* Build L2TP header */
 959         pppol2tp_build_l2tp_header(session, skb->data);
 960         skb_put(skb, hdr_len);
 961
 962         /* Add PPP header */
 963         skb->data[0] = ppph[0];
 964         skb->data[1] = ppph[1];
 965         skb_put(skb, 2);
 966
 967         /* Copy user data into skb */
 968         error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
 969         if (error < 0) {
 970                 kfree_skb(skb);
 971                 goto error_put_sess_tun;
 972         }
 973         skb_put(skb, total_len);
 974
 975         /* Calculate UDP checksum if configured to do so */
 976         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
 977                 skb->ip_summed = CHECKSUM_NONE;
 978         else if (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
 979                 skb->ip_summed = CHECKSUM_COMPLETE;
 980                 csum = skb_checksum(skb, 0, udp_len, 0);
 981                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
 982                                               udp_len, IPPROTO_UDP, csum);
 983                 if (uh->check == 0)
 984                         uh->check = CSUM_MANGLED_0;
 985         } else {
 986                 skb->ip_summed = CHECKSUM_PARTIAL;
 987                 skb->csum_start = skb_transport_header(skb) - skb->head;
 988                 skb->csum_offset = offsetof(struct udphdr, check);
 989                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
 990                                                udp_len, IPPROTO_UDP, 0);
 991         }
 992
 993         /* Debug */
 994         if (session->send_seq)
 995                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 996                        "%s: send %Zd bytes, ns=%hu\n", session->name,
 997                        total_len, session->ns - 1);
 998         else
 999                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1000                        "%s: send %Zd bytes\n", session->name, total_len);
1001
1002         if (session->debug & PPPOL2TP_MSG_DATA) {
1003                 int i;
1004                 unsigned char *datap = skb->data;
1005
1006                 printk(KERN_DEBUG "%s: xmit:", session->name);
1007                 for (i = 0; i < total_len; i++) {
1008                         printk(" %02X", *datap++);
1009                         if (i == 15) {
1010                                 printk(" ...");
1011                                 break;
1012                         }
1013                 }
1014                 printk("\n");
1015         }
1016
1017         /* Queue the packet to IP for output */
1018         len = skb->len;
1019         error = ip_queue_xmit(skb, 1);
1020
1021         /* Update stats */
1022         if (error >= 0) {
1023                 tunnel->stats.tx_packets++;
1024                 tunnel->stats.tx_bytes += len;
1025                 session->stats.tx_packets++;
1026                 session->stats.tx_bytes += len;
1027         } else {
1028                 tunnel->stats.tx_errors++;
1029                 session->stats.tx_errors++;
1030         }
1031
1032         return error;
1033
1034 error_put_sess_tun:
1035         sock_put(session->tunnel_sock);
1036 error_put_sess:
1037         sock_put(sk);
1038 error:
1039         return error;
1040 }
1041
1042 /* Automatically called when the skb is freed.
1043  */
1044 static void pppol2tp_sock_wfree(struct sk_buff *skb)
1045 {
1046         sock_put(skb->sk);
1047 }
1048
1049 /* For data skbs that we transmit, we associate with the tunnel socket
1050  * but don't do accounting.
1051  */
1052 static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1053 {
1054         sock_hold(sk);
1055         skb->sk = sk;
1056         skb->destructor = pppol2tp_sock_wfree;
1057 }
1058
1059 /* Transmit function called by generic PPP driver.  Sends PPP frame
1060  * over PPPoL2TP socket.
1061  *
1062  * This is almost the same as pppol2tp_sendmsg(), but rather than
1063  * being called with a msghdr from userspace, it is called with a skb
1064  * from the kernel.
1065  *
1066  * The supplied skb from ppp doesn't have enough headroom for the
1067  * insertion of L2TP, UDP and IP headers so we need to allocate more
1068  * headroom in the skb. This will create a cloned skb. But we must be
1069  * careful in the error case because the caller will expect to free
1070  * the skb it supplied, not our cloned skb. So we take care to always
1071  * leave the original skb unfreed if we return an error.
1072  */
1073 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
1074 {
1075         static const u8 ppph[2] = { 0xff, 0x03 };
1076         struct sock *sk = (struct sock *) chan->private;
1077         struct sock *sk_tun;
1078         int hdr_len;
1079         u16 udp_len;
1080         struct pppol2tp_session *session;
1081         struct pppol2tp_tunnel *tunnel;
1082         int rc;
1083         int headroom;
1084         int data_len = skb->len;
1085         struct inet_sock *inet;
1086         __wsum csum;
1087         struct udphdr *uh;
1088         unsigned int len;
1089         int old_headroom;
1090         int new_headroom;
1091
1092         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
1093                 goto abort;
1094
1095         /* Get session and tunnel contexts from the socket */
1096         session = pppol2tp_sock_to_session(sk);
1097         if (session == NULL)
1098                 goto abort;
1099
1100         sk_tun = session->tunnel_sock;
1101         if (sk_tun == NULL)
1102                 goto abort_put_sess;
1103         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
1104         if (tunnel == NULL)
1105                 goto abort_put_sess;
1106
1107         /* What header length is configured for this session? */
1108         hdr_len = pppol2tp_l2tp_header_len(session);
1109
1110         /* Check that there's enough headroom in the skb to insert IP,
1111          * UDP and L2TP and PPP headers. If not enough, expand it to
1112          * make room. Adjust truesize.
1113          */
1114         headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1115                 sizeof(struct udphdr) + hdr_len + sizeof(ppph);
1116         old_headroom = skb_headroom(skb);
1117         if (skb_cow_head(skb, headroom))
1118                 goto abort_put_sess_tun;
1119
1120         new_headroom = skb_headroom(skb);
1121         skb_orphan(skb);
1122         skb->truesize += new_headroom - old_headroom;
1123
1124         /* Setup PPP header */
1125         __skb_push(skb, sizeof(ppph));
1126         skb->data[0] = ppph[0];
1127         skb->data[1] = ppph[1];
1128
1129         /* Setup L2TP header */
1130         pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
1131
1132         udp_len = sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len;
1133
1134         /* Setup UDP header */
1135         inet = inet_sk(sk_tun);
1136         __skb_push(skb, sizeof(*uh));
1137         skb_reset_transport_header(skb);
1138         uh = udp_hdr(skb);
1139         uh->source = inet->sport;
1140         uh->dest = inet->dport;
1141         uh->len = htons(udp_len);
1142         uh->check = 0;
1143
1144         /* Debug */
1145         if (session->send_seq)
1146                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1147                        "%s: send %d bytes, ns=%hu\n", session->name,
1148                        data_len, session->ns - 1);
1149         else
1150                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1151                        "%s: send %d bytes\n", session->name, data_len);
1152
1153         if (session->debug & PPPOL2TP_MSG_DATA) {
1154                 int i;
1155                 unsigned char *datap = skb->data;
1156
1157                 printk(KERN_DEBUG "%s: xmit:", session->name);
1158                 for (i = 0; i < data_len; i++) {
1159                         printk(" %02X", *datap++);
1160                         if (i == 31) {
1161                                 printk(" ...");
1162                                 break;
1163                         }
1164                 }
1165                 printk("\n");
1166         }
1167
1168         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1169         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1170                               IPSKB_REROUTED);
1171         nf_reset(skb);
1172
1173         /* Get routing info from the tunnel socket */
1174         skb_dst_drop(skb);
1175         skb_dst_set(skb, dst_clone(__sk_dst_get(sk_tun)));
1176         pppol2tp_skb_set_owner_w(skb, sk_tun);
1177
1178         /* Calculate UDP checksum if configured to do so */
1179         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
1180                 skb->ip_summed = CHECKSUM_NONE;
1181         else if (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
1182                 skb->ip_summed = CHECKSUM_COMPLETE;
1183                 csum = skb_checksum(skb, 0, udp_len, 0);
1184                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
1185                                               udp_len, IPPROTO_UDP, csum);
1186                 if (uh->check == 0)
1187                         uh->check = CSUM_MANGLED_0;
1188         } else {
1189                 skb->ip_summed = CHECKSUM_PARTIAL;
1190                 skb->csum_start = skb_transport_header(skb) - skb->head;
1191                 skb->csum_offset = offsetof(struct udphdr, check);
1192                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
1193                                                udp_len, IPPROTO_UDP, 0);
1194         }
1195
1196         /* Queue the packet to IP for output */
1197         len = skb->len;
1198         rc = ip_queue_xmit(skb, 1);
1199
1200         /* Update stats */
1201         if (rc >= 0) {
1202                 tunnel->stats.tx_packets++;
1203                 tunnel->stats.tx_bytes += len;
1204                 session->stats.tx_packets++;
1205                 session->stats.tx_bytes += len;
1206         } else {
1207                 tunnel->stats.tx_errors++;
1208                 session->stats.tx_errors++;
1209         }
1210
1211         sock_put(sk_tun);
1212         sock_put(sk);
1213         return 1;
1214
1215 abort_put_sess_tun:
1216         sock_put(sk_tun);
1217 abort_put_sess:
1218         sock_put(sk);
1219 abort:
1220         /* Free the original skb */
1221         kfree_skb(skb);
1222         return 1;
1223 }
1224
1225 /*****************************************************************************
1226  * Session (and tunnel control) socket create/destroy.
1227  *****************************************************************************/
1228
1229 /* When the tunnel UDP socket is closed, all the attached sockets need to go
1230  * too.
1231  */
1232 static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel)
1233 {
1234         int hash;
1235         struct hlist_node *walk;
1236         struct hlist_node *tmp;
1237         struct pppol2tp_session *session;
1238         struct sock *sk;
1239
1240         BUG_ON(tunnel == NULL);
1241
1242         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1243                "%s: closing all sessions...\n", tunnel->name);
1244
1245         write_lock_bh(&tunnel->hlist_lock);
1246         for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) {
1247 again:
1248                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1249                         struct sk_buff *skb;
1250
1251                         session = hlist_entry(walk, struct pppol2tp_session, hlist);
1252
1253                         sk = session->sock;
1254
1255                         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1256                                "%s: closing session\n", session->name);
1257
1258                         hlist_del_init(&session->hlist);
1259
1260                         /* Since we should hold the sock lock while
1261                          * doing any unbinding, we need to release the
1262                          * lock we're holding before taking that lock.
1263                          * Hold a reference to the sock so it doesn't
1264                          * disappear as we're jumping between locks.
1265                          */
1266                         sock_hold(sk);
1267                         write_unlock_bh(&tunnel->hlist_lock);
1268                         lock_sock(sk);
1269
1270                         if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
1271                                 pppox_unbind_sock(sk);
1272                                 sk->sk_state = PPPOX_DEAD;
1273                                 sk->sk_state_change(sk);
1274                         }
1275
1276                         /* Purge any queued data */
1277                         skb_queue_purge(&sk->sk_receive_queue);
1278                         skb_queue_purge(&sk->sk_write_queue);
1279                         while ((skb = skb_dequeue(&session->reorder_q))) {
1280                                 kfree_skb(skb);
1281                                 sock_put(sk);
1282                         }
1283
1284                         release_sock(sk);
1285                         sock_put(sk);
1286
1287                         /* Now restart from the beginning of this hash
1288                          * chain.  We always remove a session from the
1289                          * list so we are guaranteed to make forward
1290                          * progress.
1291                          */
1292                         write_lock_bh(&tunnel->hlist_lock);
1293                         goto again;
1294                 }
1295         }
1296         write_unlock_bh(&tunnel->hlist_lock);
1297 }
1298
1299 /* Really kill the tunnel.
1300  * Come here only when all sessions have been cleared from the tunnel.
1301  */
1302 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
1303 {
1304         struct pppol2tp_net *pn = pppol2tp_pernet(tunnel->pppol2tp_net);
1305
1306         /* Remove from socket list */
1307         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1308         list_del_init(&tunnel->list);
1309         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1310
1311         atomic_dec(&pppol2tp_tunnel_count);
1312         kfree(tunnel);
1313 }
1314
1315 /* Tunnel UDP socket destruct hook.
1316  * The tunnel context is deleted only when all session sockets have been
1317  * closed.
1318  */
1319 static void pppol2tp_tunnel_destruct(struct sock *sk)
1320 {
1321         struct pppol2tp_tunnel *tunnel;
1322
1323         tunnel = sk->sk_user_data;
1324         if (tunnel == NULL)
1325                 goto end;
1326
1327         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1328                "%s: closing...\n", tunnel->name);
1329
1330         /* Close all sessions */
1331         pppol2tp_tunnel_closeall(tunnel);
1332
1333         /* No longer an encapsulation socket. See net/ipv4/udp.c */
1334         (udp_sk(sk))->encap_type = 0;
1335         (udp_sk(sk))->encap_rcv = NULL;
1336
1337         /* Remove hooks into tunnel socket */
1338         tunnel->sock = NULL;
1339         sk->sk_destruct = tunnel->old_sk_destruct;
1340         sk->sk_user_data = NULL;
1341
1342         /* Call original (UDP) socket descructor */
1343         if (sk->sk_destruct != NULL)
1344                 (*sk->sk_destruct)(sk);
1345
1346         pppol2tp_tunnel_dec_refcount(tunnel);
1347
1348 end:
1349         return;
1350 }
1351
1352 /* Really kill the session socket. (Called from sock_put() if
1353  * refcnt == 0.)
1354  */
1355 static void pppol2tp_session_destruct(struct sock *sk)
1356 {
1357         struct pppol2tp_session *session = NULL;
1358
1359         if (sk->sk_user_data != NULL) {
1360                 struct pppol2tp_tunnel *tunnel;
1361
1362                 session = sk->sk_user_data;
1363                 if (session == NULL)
1364                         goto out;
1365
1366                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
1367
1368                 /* Don't use pppol2tp_sock_to_tunnel() here to
1369                  * get the tunnel context because the tunnel
1370                  * socket might have already been closed (its
1371                  * sk->sk_user_data will be NULL) so use the
1372                  * session's private tunnel ptr instead.
1373                  */
1374                 tunnel = session->tunnel;
1375                 if (tunnel != NULL) {
1376                         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1377
1378                         /* If session_id is zero, this is a null
1379                          * session context, which was created for a
1380                          * socket that is being used only to manage
1381                          * tunnels.
1382                          */
1383                         if (session->tunnel_addr.s_session != 0) {
1384                                 /* Delete the session socket from the
1385                                  * hash
1386                                  */
1387                                 write_lock_bh(&tunnel->hlist_lock);
1388                                 hlist_del_init(&session->hlist);
1389                                 write_unlock_bh(&tunnel->hlist_lock);
1390
1391                                 atomic_dec(&pppol2tp_session_count);
1392                         }
1393
1394                         /* This will delete the tunnel context if this
1395                          * is the last session on the tunnel.
1396                          */
1397                         session->tunnel = NULL;
1398                         session->tunnel_sock = NULL;
1399                         pppol2tp_tunnel_dec_refcount(tunnel);
1400                 }
1401         }
1402
1403         kfree(session);
1404 out:
1405         return;
1406 }
1407
1408 /* Called when the PPPoX socket (session) is closed.
1409  */
1410 static int pppol2tp_release(struct socket *sock)
1411 {
1412         struct sock *sk = sock->sk;
1413         struct pppol2tp_session *session;
1414         int error;
1415
1416         if (!sk)
1417                 return 0;
1418
1419         error = -EBADF;
1420         lock_sock(sk);
1421         if (sock_flag(sk, SOCK_DEAD) != 0)
1422                 goto error;
1423
1424         pppox_unbind_sock(sk);
1425
1426         /* Signal the death of the socket. */
1427         sk->sk_state = PPPOX_DEAD;
1428         sock_orphan(sk);
1429         sock->sk = NULL;
1430
1431         session = pppol2tp_sock_to_session(sk);
1432
1433         /* Purge any queued data */
1434         skb_queue_purge(&sk->sk_receive_queue);
1435         skb_queue_purge(&sk->sk_write_queue);
1436         if (session != NULL) {
1437                 struct sk_buff *skb;
1438                 while ((skb = skb_dequeue(&session->reorder_q))) {
1439                         kfree_skb(skb);
1440                         sock_put(sk);
1441                 }
1442                 sock_put(sk);
1443         }
1444
1445         release_sock(sk);
1446
1447         /* This will delete the session context via
1448          * pppol2tp_session_destruct() if the socket's refcnt drops to
1449          * zero.
1450          */
1451         sock_put(sk);
1452
1453         return 0;
1454
1455 error:
1456         release_sock(sk);
1457         return error;
1458 }
1459
1460 /* Internal function to prepare a tunnel (UDP) socket to have PPPoX
1461  * sockets attached to it.
1462  */
1463 static struct sock *pppol2tp_prepare_tunnel_socket(struct net *net,
1464                                         int fd, u16 tunnel_id, int *error)
1465 {
1466         int err;
1467         struct socket *sock = NULL;
1468         struct sock *sk;
1469         struct pppol2tp_tunnel *tunnel;
1470         struct pppol2tp_net *pn;
1471         struct sock *ret = NULL;
1472
1473         /* Get the tunnel UDP socket from the fd, which was opened by
1474          * the userspace L2TP daemon.
1475          */
1476         err = -EBADF;
1477         sock = sockfd_lookup(fd, &err);
1478         if (!sock) {
1479                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1480                        "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1481                        tunnel_id, fd, err);
1482                 goto err;
1483         }
1484
1485         sk = sock->sk;
1486
1487         /* Quick sanity checks */
1488         err = -EPROTONOSUPPORT;
1489         if (sk->sk_protocol != IPPROTO_UDP) {
1490                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1491                        "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1492                        tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1493                 goto err;
1494         }
1495         err = -EAFNOSUPPORT;
1496         if (sock->ops->family != AF_INET) {
1497                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1498                        "tunl %hu: fd %d wrong family, got %d, expected %d\n",
1499                        tunnel_id, fd, sock->ops->family, AF_INET);
1500                 goto err;
1501         }
1502
1503         err = -ENOTCONN;
1504
1505         /* Check if this socket has already been prepped */
1506         tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;
1507         if (tunnel != NULL) {
1508                 /* User-data field already set */
1509                 err = -EBUSY;
1510                 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1511
1512                 /* This socket has already been prepped */
1513                 ret = tunnel->sock;
1514                 goto out;
1515         }
1516
1517         /* This socket is available and needs prepping. Create a new tunnel
1518          * context and init it.
1519          */
1520         sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL);
1521         if (sk->sk_user_data == NULL) {
1522                 err = -ENOMEM;
1523                 goto err;
1524         }
1525
1526         tunnel->magic = L2TP_TUNNEL_MAGIC;
1527         sprintf(&tunnel->name[0], "tunl %hu", tunnel_id);
1528
1529         tunnel->stats.tunnel_id = tunnel_id;
1530         tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS;
1531
1532         /* Hook on the tunnel socket destructor so that we can cleanup
1533          * if the tunnel socket goes away.
1534          */
1535         tunnel->old_sk_destruct = sk->sk_destruct;
1536         sk->sk_destruct = &pppol2tp_tunnel_destruct;
1537
1538         tunnel->sock = sk;
1539         sk->sk_allocation = GFP_ATOMIC;
1540
1541         /* Misc init */
1542         rwlock_init(&tunnel->hlist_lock);
1543
1544         /* The net we belong to */
1545         tunnel->pppol2tp_net = net;
1546         pn = pppol2tp_pernet(net);
1547
1548         /* Add tunnel to our list */
1549         INIT_LIST_HEAD(&tunnel->list);
1550         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1551         list_add(&tunnel->list, &pn->pppol2tp_tunnel_list);
1552         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1553         atomic_inc(&pppol2tp_tunnel_count);
1554
1555         /* Bump the reference count. The tunnel context is deleted
1556          * only when this drops to zero.
1557          */
1558         pppol2tp_tunnel_inc_refcount(tunnel);
1559
1560         /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1561         (udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP;
1562         (udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv;
1563
1564         ret = tunnel->sock;
1565
1566         *error = 0;
1567 out:
1568         if (sock)
1569                 sockfd_put(sock);
1570
1571         return ret;
1572
1573 err:
1574         *error = err;
1575         goto out;
1576 }
1577
1578 static struct proto pppol2tp_sk_proto = {
1579         .name     = "PPPOL2TP",
1580         .owner    = THIS_MODULE,
1581         .obj_size = sizeof(struct pppox_sock),
1582 };
1583
1584 /* socket() handler. Initialize a new struct sock.
1585  */
1586 static int pppol2tp_create(struct net *net, struct socket *sock)
1587 {
1588         int error = -ENOMEM;
1589         struct sock *sk;
1590
1591         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
1592         if (!sk)
1593                 goto out;
1594
1595         sock_init_data(sock, sk);
1596
1597         sock->state  = SS_UNCONNECTED;
1598         sock->ops    = &pppol2tp_ops;
1599
1600         sk->sk_backlog_rcv = pppol2tp_recv_core;
1601         sk->sk_protocol    = PX_PROTO_OL2TP;
1602         sk->sk_family      = PF_PPPOX;
1603         sk->sk_state       = PPPOX_NONE;
1604         sk->sk_type        = SOCK_STREAM;
1605         sk->sk_destruct    = pppol2tp_session_destruct;
1606
1607         error = 0;
1608
1609 out:
1610         return error;
1611 }
1612
1613 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
1614  */
1615 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
1616                             int sockaddr_len, int flags)
1617 {
1618         struct sock *sk = sock->sk;
1619         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
1620         struct pppox_sock *po = pppox_sk(sk);
1621         struct sock *tunnel_sock = NULL;
1622         struct pppol2tp_session *session = NULL;
1623         struct pppol2tp_tunnel *tunnel;
1624         struct dst_entry *dst;
1625         int error = 0;
1626
1627         lock_sock(sk);
1628
1629         error = -EINVAL;
1630         if (sp->sa_protocol != PX_PROTO_OL2TP)
1631                 goto end;
1632
1633         /* Check for already bound sockets */
1634         error = -EBUSY;
1635         if (sk->sk_state & PPPOX_CONNECTED)
1636                 goto end;
1637
1638         /* We don't supporting rebinding anyway */
1639         error = -EALREADY;
1640         if (sk->sk_user_data)
1641                 goto end; /* socket is already attached */
1642
1643         /* Don't bind if s_tunnel is 0 */
1644         error = -EINVAL;
1645         if (sp->pppol2tp.s_tunnel == 0)
1646                 goto end;
1647
1648         /* Special case: prepare tunnel socket if s_session and
1649          * d_session is 0. Otherwise look up tunnel using supplied
1650          * tunnel id.
1651          */
1652         if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
1653                 tunnel_sock = pppol2tp_prepare_tunnel_socket(sock_net(sk),
1654                                                              sp->pppol2tp.fd,
1655                                                              sp->pppol2tp.s_tunnel,
1656                                                              &error);
1657                 if (tunnel_sock == NULL)
1658                         goto end;
1659
1660                 tunnel = tunnel_sock->sk_user_data;
1661         } else {
1662                 tunnel = pppol2tp_tunnel_find(sock_net(sk), sp->pppol2tp.s_tunnel);
1663
1664                 /* Error if we can't find the tunnel */
1665                 error = -ENOENT;
1666                 if (tunnel == NULL)
1667                         goto end;
1668
1669                 tunnel_sock = tunnel->sock;
1670         }
1671
1672         /* Check that this session doesn't already exist */
1673         error = -EEXIST;
1674         session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session);
1675         if (session != NULL)
1676                 goto end;
1677
1678         /* Allocate and initialize a new session context. */
1679         session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL);
1680         if (session == NULL) {
1681                 error = -ENOMEM;
1682                 goto end;
1683         }
1684
1685         skb_queue_head_init(&session->reorder_q);
1686
1687         session->magic       = L2TP_SESSION_MAGIC;
1688         session->owner       = current->pid;
1689         session->sock        = sk;
1690         session->tunnel      = tunnel;
1691         session->tunnel_sock = tunnel_sock;
1692         session->tunnel_addr = sp->pppol2tp;
1693         sprintf(&session->name[0], "sess %hu/%hu",
1694                 session->tunnel_addr.s_tunnel,
1695                 session->tunnel_addr.s_session);
1696
1697         session->stats.tunnel_id  = session->tunnel_addr.s_tunnel;
1698         session->stats.session_id = session->tunnel_addr.s_session;
1699
1700         INIT_HLIST_NODE(&session->hlist);
1701
1702         /* Inherit debug options from tunnel */
1703         session->debug = tunnel->debug;
1704
1705         /* Default MTU must allow space for UDP/L2TP/PPP
1706          * headers.
1707          */
1708         session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
1709
1710         /* If PMTU discovery was enabled, use the MTU that was discovered */
1711         dst = sk_dst_get(sk);
1712         if (dst != NULL) {
1713                 u32 pmtu = dst_mtu(__sk_dst_get(sk));
1714                 if (pmtu != 0)
1715                         session->mtu = session->mru = pmtu -
1716                                 PPPOL2TP_HEADER_OVERHEAD;
1717                 dst_release(dst);
1718         }
1719
1720         /* Special case: if source & dest session_id == 0x0000, this socket is
1721          * being created to manage the tunnel. Don't add the session to the
1722          * session hash list, just set up the internal context for use by
1723          * ioctl() and sockopt() handlers.
1724          */
1725         if ((session->tunnel_addr.s_session == 0) &&
1726             (session->tunnel_addr.d_session == 0)) {
1727                 error = 0;
1728                 sk->sk_user_data = session;
1729                 goto out_no_ppp;
1730         }
1731
1732         /* Get tunnel context from the tunnel socket */
1733         tunnel = pppol2tp_sock_to_tunnel(tunnel_sock);
1734         if (tunnel == NULL) {
1735                 error = -EBADF;
1736                 goto end;
1737         }
1738
1739         /* Right now, because we don't have a way to push the incoming skb's
1740          * straight through the UDP layer, the only header we need to worry
1741          * about is the L2TP header. This size is different depending on
1742          * whether sequence numbers are enabled for the data channel.
1743          */
1744         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1745
1746         po->chan.private = sk;
1747         po->chan.ops     = &pppol2tp_chan_ops;
1748         po->chan.mtu     = session->mtu;
1749
1750         error = ppp_register_net_channel(sock_net(sk), &po->chan);
1751         if (error)
1752                 goto end_put_tun;
1753
1754         /* This is how we get the session context from the socket. */
1755         sk->sk_user_data = session;
1756
1757         /* Add session to the tunnel's hash list */
1758         write_lock_bh(&tunnel->hlist_lock);
1759         hlist_add_head(&session->hlist,
1760                        pppol2tp_session_id_hash(tunnel,
1761                                                 session->tunnel_addr.s_session));
1762         write_unlock_bh(&tunnel->hlist_lock);
1763
1764         atomic_inc(&pppol2tp_session_count);
1765
1766 out_no_ppp:
1767         pppol2tp_tunnel_inc_refcount(tunnel);
1768         sk->sk_state = PPPOX_CONNECTED;
1769         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1770                "%s: created\n", session->name);
1771
1772 end_put_tun:
1773         sock_put(tunnel_sock);
1774 end:
1775         release_sock(sk);
1776
1777         if (error != 0) {
1778                 if (session)
1779                         PRINTK(session->debug,
1780                                 PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1781                                 "%s: connect failed: %d\n",
1782                                 session->name, error);
1783                 else
1784                         PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1785                                 "connect failed: %d\n", error);
1786         }
1787
1788         return error;
1789 }
1790
1791 /* getname() support.
1792  */
1793 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
1794                             int *usockaddr_len, int peer)
1795 {
1796         int len = sizeof(struct sockaddr_pppol2tp);
1797         struct sockaddr_pppol2tp sp;
1798         int error = 0;
1799         struct pppol2tp_session *session;
1800
1801         error = -ENOTCONN;
1802         if (sock->sk->sk_state != PPPOX_CONNECTED)
1803                 goto end;
1804
1805         session = pppol2tp_sock_to_session(sock->sk);
1806         if (session == NULL) {
1807                 error = -EBADF;
1808                 goto end;
1809         }
1810
1811         sp.sa_family    = AF_PPPOX;
1812         sp.sa_protocol  = PX_PROTO_OL2TP;
1813         memcpy(&sp.pppol2tp, &session->tunnel_addr,
1814                sizeof(struct pppol2tp_addr));
1815
1816         memcpy(uaddr, &sp, len);
1817
1818         *usockaddr_len = len;
1819
1820         error = 0;
1821         sock_put(sock->sk);
1822
1823 end:
1824         return error;
1825 }
1826
1827 /****************************************************************************
1828  * ioctl() handlers.
1829  *
1830  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1831  * sockets. However, in order to control kernel tunnel features, we allow
1832  * userspace to create a special "tunnel" PPPoX socket which is used for
1833  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
1834  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1835  * calls.
1836  ****************************************************************************/
1837
1838 /* Session ioctl helper.
1839  */
1840 static int pppol2tp_session_ioctl(struct pppol2tp_session *session,
1841                                   unsigned int cmd, unsigned long arg)
1842 {
1843         struct ifreq ifr;
1844         int err = 0;
1845         struct sock *sk = session->sock;
1846         int val = (int) arg;
1847
1848         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1849                "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1850                session->name, cmd, arg);
1851
1852         sock_hold(sk);
1853
1854         switch (cmd) {
1855         case SIOCGIFMTU:
1856                 err = -ENXIO;
1857                 if (!(sk->sk_state & PPPOX_CONNECTED))
1858                         break;
1859
1860                 err = -EFAULT;
1861                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1862                         break;
1863                 ifr.ifr_mtu = session->mtu;
1864                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1865                         break;
1866
1867                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1868                        "%s: get mtu=%d\n", session->name, session->mtu);
1869                 err = 0;
1870                 break;
1871
1872         case SIOCSIFMTU:
1873                 err = -ENXIO;
1874                 if (!(sk->sk_state & PPPOX_CONNECTED))
1875                         break;
1876
1877                 err = -EFAULT;
1878                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1879                         break;
1880
1881                 session->mtu = ifr.ifr_mtu;
1882
1883                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1884                        "%s: set mtu=%d\n", session->name, session->mtu);
1885                 err = 0;
1886                 break;
1887
1888         case PPPIOCGMRU:
1889                 err = -ENXIO;
1890                 if (!(sk->sk_state & PPPOX_CONNECTED))
1891                         break;
1892
1893                 err = -EFAULT;
1894                 if (put_user(session->mru, (int __user *) arg))
1895                         break;
1896
1897                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1898                        "%s: get mru=%d\n", session->name, session->mru);
1899                 err = 0;
1900                 break;
1901
1902         case PPPIOCSMRU:
1903                 err = -ENXIO;
1904                 if (!(sk->sk_state & PPPOX_CONNECTED))
1905                         break;
1906
1907                 err = -EFAULT;
1908                 if (get_user(val,(int __user *) arg))
1909                         break;
1910
1911                 session->mru = val;
1912                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1913                        "%s: set mru=%d\n", session->name, session->mru);
1914                 err = 0;
1915                 break;
1916
1917         case PPPIOCGFLAGS:
1918                 err = -EFAULT;
1919                 if (put_user(session->flags, (int __user *) arg))
1920                         break;
1921
1922                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1923                        "%s: get flags=%d\n", session->name, session->flags);
1924                 err = 0;
1925                 break;
1926
1927         case PPPIOCSFLAGS:
1928                 err = -EFAULT;
1929                 if (get_user(val, (int __user *) arg))
1930                         break;
1931                 session->flags = val;
1932                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1933                        "%s: set flags=%d\n", session->name, session->flags);
1934                 err = 0;
1935                 break;
1936
1937         case PPPIOCGL2TPSTATS:
1938                 err = -ENXIO;
1939                 if (!(sk->sk_state & PPPOX_CONNECTED))
1940                         break;
1941
1942                 if (copy_to_user((void __user *) arg, &session->stats,
1943                                  sizeof(session->stats)))
1944                         break;
1945                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1946                        "%s: get L2TP stats\n", session->name);
1947                 err = 0;
1948                 break;
1949
1950         default:
1951                 err = -ENOSYS;
1952                 break;
1953         }
1954
1955         sock_put(sk);
1956
1957         return err;
1958 }
1959
1960 /* Tunnel ioctl helper.
1961  *
1962  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1963  * specifies a session_id, the session ioctl handler is called. This allows an
1964  * application to retrieve session stats via a tunnel socket.
1965  */
1966 static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel,
1967                                  unsigned int cmd, unsigned long arg)
1968 {
1969         int err = 0;
1970         struct sock *sk = tunnel->sock;
1971         struct pppol2tp_ioc_stats stats_req;
1972
1973         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1974                "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name,
1975                cmd, arg);
1976
1977         sock_hold(sk);
1978
1979         switch (cmd) {
1980         case PPPIOCGL2TPSTATS:
1981                 err = -ENXIO;
1982                 if (!(sk->sk_state & PPPOX_CONNECTED))
1983                         break;
1984
1985                 if (copy_from_user(&stats_req, (void __user *) arg,
1986                                    sizeof(stats_req))) {
1987                         err = -EFAULT;
1988                         break;
1989                 }
1990                 if (stats_req.session_id != 0) {
1991                         /* resend to session ioctl handler */
1992                         struct pppol2tp_session *session =
1993                                 pppol2tp_session_find(tunnel, stats_req.session_id);
1994                         if (session != NULL)
1995                                 err = pppol2tp_session_ioctl(session, cmd, arg);
1996                         else
1997                                 err = -EBADR;
1998                         break;
1999                 }
2000 #ifdef CONFIG_XFRM
2001                 tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
2002 #endif
2003                 if (copy_to_user((void __user *) arg, &tunnel->stats,
2004                                  sizeof(tunnel->stats))) {
2005                         err = -EFAULT;
2006                         break;
2007                 }
2008                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2009                        "%s: get L2TP stats\n", tunnel->name);
2010                 err = 0;
2011                 break;
2012
2013         default:
2014                 err = -ENOSYS;
2015                 break;
2016         }
2017
2018         sock_put(sk);
2019
2020         return err;
2021 }
2022
2023 /* Main ioctl() handler.
2024  * Dispatch to tunnel or session helpers depending on the socket.
2025  */
2026 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
2027                           unsigned long arg)
2028 {
2029         struct sock *sk = sock->sk;
2030         struct pppol2tp_session *session;
2031         struct pppol2tp_tunnel *tunnel;
2032         int err;
2033
2034         if (!sk)
2035                 return 0;
2036
2037         err = -EBADF;
2038         if (sock_flag(sk, SOCK_DEAD) != 0)
2039                 goto end;
2040
2041         err = -ENOTCONN;
2042         if ((sk->sk_user_data == NULL) ||
2043             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
2044                 goto end;
2045
2046         /* Get session context from the socket */
2047         err = -EBADF;
2048         session = pppol2tp_sock_to_session(sk);
2049         if (session == NULL)
2050                 goto end;
2051
2052         /* Special case: if session's session_id is zero, treat ioctl as a
2053          * tunnel ioctl
2054          */
2055         if ((session->tunnel_addr.s_session == 0) &&
2056             (session->tunnel_addr.d_session == 0)) {
2057                 err = -EBADF;
2058                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2059                 if (tunnel == NULL)
2060                         goto end_put_sess;
2061
2062                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
2063                 sock_put(session->tunnel_sock);
2064                 goto end_put_sess;
2065         }
2066
2067         err = pppol2tp_session_ioctl(session, cmd, arg);
2068
2069 end_put_sess:
2070         sock_put(sk);
2071 end:
2072         return err;
2073 }
2074
2075 /*****************************************************************************
2076  * setsockopt() / getsockopt() support.
2077  *
2078  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
2079  * sockets. In order to control kernel tunnel features, we allow userspace to
2080  * create a special "tunnel" PPPoX socket which is used for control only.
2081  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
2082  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
2083  *****************************************************************************/
2084
2085 /* Tunnel setsockopt() helper.
2086  */
2087 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
2088                                       struct pppol2tp_tunnel *tunnel,
2089                                       int optname, int val)
2090 {
2091         int err = 0;
2092
2093         switch (optname) {
2094         case PPPOL2TP_SO_DEBUG:
2095                 tunnel->debug = val;
2096                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2097                        "%s: set debug=%x\n", tunnel->name, tunnel->debug);
2098                 break;
2099
2100         default:
2101                 err = -ENOPROTOOPT;
2102                 break;
2103         }
2104
2105         return err;
2106 }
2107
2108 /* Session setsockopt helper.
2109  */
2110 static int pppol2tp_session_setsockopt(struct sock *sk,
2111                                        struct pppol2tp_session *session,
2112                                        int optname, int val)
2113 {
2114         int err = 0;
2115
2116         switch (optname) {
2117         case PPPOL2TP_SO_RECVSEQ:
2118                 if ((val != 0) && (val != 1)) {
2119                         err = -EINVAL;
2120                         break;
2121                 }
2122                 session->recv_seq = val ? -1 : 0;
2123                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2124                        "%s: set recv_seq=%d\n", session->name,
2125                        session->recv_seq);
2126                 break;
2127
2128         case PPPOL2TP_SO_SENDSEQ:
2129                 if ((val != 0) && (val != 1)) {
2130                         err = -EINVAL;
2131                         break;
2132                 }
2133                 session->send_seq = val ? -1 : 0;
2134                 {
2135                         struct sock *ssk      = session->sock;
2136                         struct pppox_sock *po = pppox_sk(ssk);
2137                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
2138                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
2139                 }
2140                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2141                        "%s: set send_seq=%d\n", session->name, session->send_seq);
2142                 break;
2143
2144         case PPPOL2TP_SO_LNSMODE:
2145                 if ((val != 0) && (val != 1)) {
2146                         err = -EINVAL;
2147                         break;
2148                 }
2149                 session->lns_mode = val ? -1 : 0;
2150                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2151                        "%s: set lns_mode=%d\n", session->name,
2152                        session->lns_mode);
2153                 break;
2154
2155         case PPPOL2TP_SO_DEBUG:
2156                 session->debug = val;
2157                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2158                        "%s: set debug=%x\n", session->name, session->debug);
2159                 break;
2160
2161         case PPPOL2TP_SO_REORDERTO:
2162                 session->reorder_timeout = msecs_to_jiffies(val);
2163                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2164                        "%s: set reorder_timeout=%d\n", session->name,
2165                        session->reorder_timeout);
2166                 break;
2167
2168         default:
2169                 err = -ENOPROTOOPT;
2170                 break;
2171         }
2172
2173         return err;
2174 }
2175
2176 /* Main setsockopt() entry point.
2177  * Does API checks, then calls either the tunnel or session setsockopt
2178  * handler, according to whether the PPPoL2TP socket is a for a regular
2179  * session or the special tunnel type.
2180  */
2181 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
2182                                char __user *optval, unsigned int optlen)
2183 {
2184         struct sock *sk = sock->sk;
2185         struct pppol2tp_session *session = sk->sk_user_data;
2186         struct pppol2tp_tunnel *tunnel;
2187         int val;
2188         int err;
2189
2190         if (level != SOL_PPPOL2TP)
2191                 return udp_prot.setsockopt(sk, level, optname, optval, optlen);
2192
2193         if (optlen < sizeof(int))
2194                 return -EINVAL;
2195
2196         if (get_user(val, (int __user *)optval))
2197                 return -EFAULT;
2198
2199         err = -ENOTCONN;
2200         if (sk->sk_user_data == NULL)
2201                 goto end;
2202
2203         /* Get session context from the socket */
2204         err = -EBADF;
2205         session = pppol2tp_sock_to_session(sk);
2206         if (session == NULL)
2207                 goto end;
2208
2209         /* Special case: if session_id == 0x0000, treat as operation on tunnel
2210          */
2211         if ((session->tunnel_addr.s_session == 0) &&
2212             (session->tunnel_addr.d_session == 0)) {
2213                 err = -EBADF;
2214                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2215                 if (tunnel == NULL)
2216                         goto end_put_sess;
2217
2218                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
2219                 sock_put(session->tunnel_sock);
2220         } else
2221                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
2222
2223         err = 0;
2224
2225 end_put_sess:
2226         sock_put(sk);
2227 end:
2228         return err;
2229 }
2230
2231 /* Tunnel getsockopt helper. Called with sock locked.
2232  */
2233 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
2234                                       struct pppol2tp_tunnel *tunnel,
2235                                       int optname, int *val)
2236 {
2237         int err = 0;
2238
2239         switch (optname) {
2240         case PPPOL2TP_SO_DEBUG:
2241                 *val = tunnel->debug;
2242                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2243                        "%s: get debug=%x\n", tunnel->name, tunnel->debug);
2244                 break;
2245
2246         default:
2247                 err = -ENOPROTOOPT;
2248                 break;
2249         }
2250
2251         return err;
2252 }
2253
2254 /* Session getsockopt helper. Called with sock locked.
2255  */
2256 static int pppol2tp_session_getsockopt(struct sock *sk,
2257                                        struct pppol2tp_session *session,
2258                                        int optname, int *val)
2259 {
2260         int err = 0;
2261
2262         switch (optname) {
2263         case PPPOL2TP_SO_RECVSEQ:
2264                 *val = session->recv_seq;
2265                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2266                        "%s: get recv_seq=%d\n", session->name, *val);
2267                 break;
2268
2269         case PPPOL2TP_SO_SENDSEQ:
2270                 *val = session->send_seq;
2271                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2272                        "%s: get send_seq=%d\n", session->name, *val);
2273                 break;
2274
2275         case PPPOL2TP_SO_LNSMODE:
2276                 *val = session->lns_mode;
2277                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2278                        "%s: get lns_mode=%d\n", session->name, *val);
2279                 break;
2280
2281         case PPPOL2TP_SO_DEBUG:
2282                 *val = session->debug;
2283                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2284                        "%s: get debug=%d\n", session->name, *val);
2285                 break;
2286
2287         case PPPOL2TP_SO_REORDERTO:
2288                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
2289                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2290                        "%s: get reorder_timeout=%d\n", session->name, *val);
2291                 break;
2292
2293         default:
2294                 err = -ENOPROTOOPT;
2295         }
2296
2297         return err;
2298 }
2299
2300 /* Main getsockopt() entry point.
2301  * Does API checks, then calls either the tunnel or session getsockopt
2302  * handler, according to whether the PPPoX socket is a for a regular session
2303  * or the special tunnel type.
2304  */
2305 static int pppol2tp_getsockopt(struct socket *sock, int level,
2306                                int optname, char __user *optval, int __user *optlen)
2307 {
2308         struct sock *sk = sock->sk;
2309         struct pppol2tp_session *session = sk->sk_user_data;
2310         struct pppol2tp_tunnel *tunnel;
2311         int val, len;
2312         int err;
2313
2314         if (level != SOL_PPPOL2TP)
2315                 return udp_prot.getsockopt(sk, level, optname, optval, optlen);
2316
2317         if (get_user(len, (int __user *) optlen))
2318                 return -EFAULT;
2319
2320         len = min_t(unsigned int, len, sizeof(int));
2321
2322         if (len < 0)
2323                 return -EINVAL;
2324
2325         err = -ENOTCONN;
2326         if (sk->sk_user_data == NULL)
2327                 goto end;
2328
2329         /* Get the session context */
2330         err = -EBADF;
2331         session = pppol2tp_sock_to_session(sk);
2332         if (session == NULL)
2333                 goto end;
2334
2335         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
2336         if ((session->tunnel_addr.s_session == 0) &&
2337             (session->tunnel_addr.d_session == 0)) {
2338                 err = -EBADF;
2339                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2340                 if (tunnel == NULL)
2341                         goto end_put_sess;
2342
2343                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
2344                 sock_put(session->tunnel_sock);
2345         } else
2346                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
2347
2348         err = -EFAULT;
2349         if (put_user(len, (int __user *) optlen))
2350                 goto end_put_sess;
2351
2352         if (copy_to_user((void __user *) optval, &val, len))
2353                 goto end_put_sess;
2354
2355         err = 0;
2356
2357 end_put_sess:
2358         sock_put(sk);
2359 end:
2360         return err;
2361 }
2362
2363 /*****************************************************************************
2364  * /proc filesystem for debug
2365  *****************************************************************************/
2366
2367 #ifdef CONFIG_PROC_FS
2368
2369 #include <linux/seq_file.h>
2370
2371 struct pppol2tp_seq_data {
2372         struct seq_net_private p;
2373         struct pppol2tp_tunnel *tunnel;         /* current tunnel */
2374         struct pppol2tp_session *session;       /* NULL means get first session in tunnel */
2375 };
2376
2377 static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
2378 {
2379         struct pppol2tp_session *session = NULL;
2380         struct hlist_node *walk;
2381         int found = 0;
2382         int next = 0;
2383         int i;
2384
2385         read_lock_bh(&tunnel->hlist_lock);
2386         for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) {
2387                 hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) {
2388                         if (curr == NULL) {
2389                                 found = 1;
2390                                 goto out;
2391                         }
2392                         if (session == curr) {
2393                                 next = 1;
2394                                 continue;
2395                         }
2396                         if (next) {
2397                                 found = 1;
2398                                 goto out;
2399                         }
2400                 }
2401         }
2402 out:
2403         read_unlock_bh(&tunnel->hlist_lock);
2404         if (!found)
2405                 session = NULL;
2406
2407         return session;
2408 }
2409
2410 static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_net *pn,
2411                                            struct pppol2tp_tunnel *curr)
2412 {
2413         struct pppol2tp_tunnel *tunnel = NULL;
2414
2415         read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
2416         if (list_is_last(&curr->list, &pn->pppol2tp_tunnel_list)) {
2417                 goto out;
2418         }
2419         tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
2420 out:
2421         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
2422
2423         return tunnel;
2424 }
2425
2426 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
2427 {
2428         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
2429         struct pppol2tp_net *pn;
2430         loff_t pos = *offs;
2431
2432         if (!pos)
2433                 goto out;
2434
2435         BUG_ON(m->private == NULL);
2436         pd = m->private;
2437         pn = pppol2tp_pernet(seq_file_net(m));
2438
2439         if (pd->tunnel == NULL) {
2440                 if (!list_empty(&pn->pppol2tp_tunnel_list))
2441                         pd->tunnel = list_entry(pn->pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
2442         } else {
2443                 pd->session = next_session(pd->tunnel, pd->session);
2444                 if (pd->session == NULL) {
2445                         pd->tunnel = next_tunnel(pn, pd->tunnel);
2446                 }
2447         }
2448
2449         /* NULL tunnel and session indicates end of list */
2450         if ((pd->tunnel == NULL) && (pd->session == NULL))
2451                 pd = NULL;
2452
2453 out:
2454         return pd;
2455 }
2456
2457 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
2458 {
2459         (*pos)++;
2460         return NULL;
2461 }
2462
2463 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
2464 {
2465         /* nothing to do */
2466 }
2467
2468 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
2469 {
2470         struct pppol2tp_tunnel *tunnel = v;
2471
2472         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
2473                    tunnel->name,
2474                    (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N',
2475                    atomic_read(&tunnel->ref_count) - 1);
2476         seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n",
2477                    tunnel->debug,
2478                    (unsigned long long)tunnel->stats.tx_packets,
2479                    (unsigned long long)tunnel->stats.tx_bytes,
2480                    (unsigned long long)tunnel->stats.tx_errors,
2481                    (unsigned long long)tunnel->stats.rx_packets,
2482                    (unsigned long long)tunnel->stats.rx_bytes,
2483                    (unsigned long long)tunnel->stats.rx_errors);
2484 }
2485
2486 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
2487 {
2488         struct pppol2tp_session *session = v;
2489
2490         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
2491                    "%04X/%04X %d %c\n",
2492                    session->name,
2493                    ntohl(session->tunnel_addr.addr.sin_addr.s_addr),
2494                    ntohs(session->tunnel_addr.addr.sin_port),
2495                    session->tunnel_addr.s_tunnel,
2496                    session->tunnel_addr.s_session,
2497                    session->tunnel_addr.d_tunnel,
2498                    session->tunnel_addr.d_session,
2499                    session->sock->sk_state,
2500                    (session == session->sock->sk_user_data) ?
2501                    'Y' : 'N');
2502         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
2503                    session->mtu, session->mru,
2504                    session->recv_seq ? 'R' : '-',
2505                    session->send_seq ? 'S' : '-',
2506                    session->lns_mode ? "LNS" : "LAC",
2507                    session->debug,
2508                    jiffies_to_msecs(session->reorder_timeout));
2509         seq_printf(m, "   %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n",
2510                    session->nr, session->ns,
2511                    (unsigned long long)session->stats.tx_packets,
2512                    (unsigned long long)session->stats.tx_bytes,
2513                    (unsigned long long)session->stats.tx_errors,
2514                    (unsigned long long)session->stats.rx_packets,
2515                    (unsigned long long)session->stats.rx_bytes,
2516                    (unsigned long long)session->stats.rx_errors);
2517 }
2518
2519 static int pppol2tp_seq_show(struct seq_file *m, void *v)
2520 {
2521         struct pppol2tp_seq_data *pd = v;
2522
2523         /* display header on line 1 */
2524         if (v == SEQ_START_TOKEN) {
2525                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
2526                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
2527                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2528                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
2529                          "dest-tid/sid state user-data-ok\n");
2530                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
2531                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2532                 goto out;
2533         }
2534
2535         /* Show the tunnel or session context.
2536          */
2537         if (pd->session == NULL)
2538                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
2539         else
2540                 pppol2tp_seq_session_show(m, pd->session);
2541
2542 out:
2543         return 0;
2544 }
2545
2546 static const struct seq_operations pppol2tp_seq_ops = {
2547         .start          = pppol2tp_seq_start,
2548         .next           = pppol2tp_seq_next,
2549         .stop           = pppol2tp_seq_stop,
2550         .show           = pppol2tp_seq_show,
2551 };
2552
2553 /* Called when our /proc file is opened. We allocate data for use when
2554  * iterating our tunnel / session contexts and store it in the private
2555  * data of the seq_file.
2556  */
2557 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
2558 {
2559         return seq_open_net(inode, file, &pppol2tp_seq_ops,
2560                             sizeof(struct pppol2tp_seq_data));
2561 }
2562
2563 static const struct file_operations pppol2tp_proc_fops = {
2564         .owner          = THIS_MODULE,
2565         .open           = pppol2tp_proc_open,
2566         .read           = seq_read,
2567         .llseek         = seq_lseek,
2568         .release        = seq_release_net,
2569 };
2570
2571 #endif /* CONFIG_PROC_FS */
2572
2573 /*****************************************************************************
2574  * Init and cleanup
2575  *****************************************************************************/
2576
2577 static const struct proto_ops pppol2tp_ops = {
2578         .family         = AF_PPPOX,
2579         .owner          = THIS_MODULE,
2580         .release        = pppol2tp_release,
2581         .bind           = sock_no_bind,
2582         .connect        = pppol2tp_connect,
2583         .socketpair     = sock_no_socketpair,
2584         .accept         = sock_no_accept,
2585         .getname        = pppol2tp_getname,
2586         .poll           = datagram_poll,
2587         .listen         = sock_no_listen,
2588         .shutdown       = sock_no_shutdown,
2589         .setsockopt     = pppol2tp_setsockopt,
2590         .getsockopt     = pppol2tp_getsockopt,
2591         .sendmsg        = pppol2tp_sendmsg,
2592         .recvmsg        = pppol2tp_recvmsg,
2593         .mmap           = sock_no_mmap,
2594         .ioctl          = pppox_ioctl,
2595 };
2596
2597 static struct pppox_proto pppol2tp_proto = {
2598         .create         = pppol2tp_create,
2599         .ioctl          = pppol2tp_ioctl
2600 };
2601
2602 static __net_init int pppol2tp_init_net(struct net *net)
2603 {
2604         struct pppol2tp_net *pn;
2605         struct proc_dir_entry *pde;
2606         int err;
2607
2608         pn = kzalloc(sizeof(*pn), GFP_KERNEL);
2609         if (!pn)
2610                 return -ENOMEM;
2611
2612         INIT_LIST_HEAD(&pn->pppol2tp_tunnel_list);
2613         rwlock_init(&pn->pppol2tp_tunnel_list_lock);
2614
2615         err = net_assign_generic(net, pppol2tp_net_id, pn);
2616         if (err)
2617                 goto out;
2618
2619         pde = proc_net_fops_create(net, "pppol2tp", S_IRUGO, &pppol2tp_proc_fops);
2620 #ifdef CONFIG_PROC_FS
2621         if (!pde) {
2622                 err = -ENOMEM;
2623                 goto out;
2624         }
2625 #endif
2626
2627         return 0;
2628
2629 out:
2630         kfree(pn);
2631         return err;
2632 }
2633
2634 static __net_exit void pppol2tp_exit_net(struct net *net)
2635 {
2636         struct pppoe_net *pn;
2637
2638         proc_net_remove(net, "pppol2tp");
2639         pn = net_generic(net, pppol2tp_net_id);
2640         /*
2641          * if someone has cached our net then
2642          * further net_generic call will return NULL
2643          */
2644         net_assign_generic(net, pppol2tp_net_id, NULL);
2645         kfree(pn);
2646 }
2647
2648 static struct pernet_operations pppol2tp_net_ops = {
2649         .init = pppol2tp_init_net,
2650         .exit = pppol2tp_exit_net,
2651 };
2652
2653 static int __init pppol2tp_init(void)
2654 {
2655         int err;
2656
2657         err = proto_register(&pppol2tp_sk_proto, 0);
2658         if (err)
2659                 goto out;
2660         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
2661         if (err)
2662                 goto out_unregister_pppol2tp_proto;
2663
2664         err = register_pernet_gen_device(&pppol2tp_net_id, &pppol2tp_net_ops);
2665         if (err)
2666                 goto out_unregister_pppox_proto;
2667
2668         printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
2669                PPPOL2TP_DRV_VERSION);
2670
2671 out:
2672         return err;
2673 out_unregister_pppox_proto:
2674         unregister_pppox_proto(PX_PROTO_OL2TP);
2675 out_unregister_pppol2tp_proto:
2676         proto_unregister(&pppol2tp_sk_proto);
2677         goto out;
2678 }
2679
2680 static void __exit pppol2tp_exit(void)
2681 {
2682         unregister_pppox_proto(PX_PROTO_OL2TP);
2683         unregister_pernet_gen_device(pppol2tp_net_id, &pppol2tp_net_ops);
2684         proto_unregister(&pppol2tp_sk_proto);
2685 }
2686
2687 module_init(pppol2tp_init);
2688 module_exit(pppol2tp_exit);
2689
2690 MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, "
2691               "James Chapman <jchapman@katalix.com>");
2692 MODULE_DESCRIPTION("PPP over L2TP over UDP");
2693 MODULE_LICENSE("GPL");
2694 MODULE_VERSION(PPPOL2TP_DRV_VERSION);