net/l2tp/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 __read_mostly;
 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->inet_saddr, inet->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         sock_put(sock);
 760
 761         return 0;
 762
 763 discard:
 764         session->stats.rx_errors++;
 765         kfree_skb(skb);
 766         sock_put(session->sock);
 767         sock_put(sock);
 768
 769         return 0;
 770
 771 discard_bad_csum:
 772         LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
 773         UDP_INC_STATS_USER(&init_net, UDP_MIB_INERRORS, 0);
 774         tunnel->stats.rx_errors++;
 775         kfree_skb(skb);
 776         sock_put(sock);
 777
 778         return 0;
 779
 780 error:
 781         /* Put UDP header back */
 782         __skb_push(skb, sizeof(struct udphdr));
 783         sock_put(sock);
 784
 785 no_tunnel:
 786         return 1;
 787 }
 788
 789 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
 790  * Return codes:
 791  * 0 : success.
 792  * <0: error
 793  * >0: skb should be passed up to userspace as UDP.
 794  */
 795 static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 796 {
 797         struct pppol2tp_tunnel *tunnel;
 798
 799         tunnel = pppol2tp_sock_to_tunnel(sk);
 800         if (tunnel == NULL)
 801                 goto pass_up;
 802
 803         PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 804                "%s: received %d bytes\n", tunnel->name, skb->len);
 805
 806         if (pppol2tp_recv_core(sk, skb))
 807                 goto pass_up_put;
 808
 809         sock_put(sk);
 810         return 0;
 811
 812 pass_up_put:
 813         sock_put(sk);
 814 pass_up:
 815         return 1;
 816 }
 817
 818 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
 819  */
 820 static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
 821                             struct msghdr *msg, size_t len,
 822                             int flags)
 823 {
 824         int err;
 825         struct sk_buff *skb;
 826         struct sock *sk = sock->sk;
 827
 828         err = -EIO;
 829         if (sk->sk_state & PPPOX_BOUND)
 830                 goto end;
 831
 832         msg->msg_namelen = 0;
 833
 834         err = 0;
 835         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 836                                 flags & MSG_DONTWAIT, &err);
 837         if (!skb)
 838                 goto end;
 839
 840         if (len > skb->len)
 841                 len = skb->len;
 842         else if (len < skb->len)
 843                 msg->msg_flags |= MSG_TRUNC;
 844
 845         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
 846         if (likely(err == 0))
 847                 err = len;
 848
 849         kfree_skb(skb);
 850 end:
 851         return err;
 852 }
 853
 854 /************************************************************************
 855  * Transmit handling
 856  ***********************************************************************/
 857
 858 /* Tell how big L2TP headers are for a particular session. This
 859  * depends on whether sequence numbers are being used.
 860  */
 861 static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session)
 862 {
 863         if (session->send_seq)
 864                 return PPPOL2TP_L2TP_HDR_SIZE_SEQ;
 865
 866         return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
 867 }
 868
 869 /* Build an L2TP header for the session into the buffer provided.
 870  */
 871 static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session,
 872                                        void *buf)
 873 {
 874         __be16 *bufp = buf;
 875         u16 flags = L2TP_HDR_VER;
 876
 877         if (session->send_seq)
 878                 flags |= L2TP_HDRFLAG_S;
 879
 880         /* Setup L2TP header.
 881          * FIXME: Can this ever be unaligned? Is direct dereferencing of
 882          * 16-bit header fields safe here for all architectures?
 883          */
 884         *bufp++ = htons(flags);
 885         *bufp++ = htons(session->tunnel_addr.d_tunnel);
 886         *bufp++ = htons(session->tunnel_addr.d_session);
 887         if (session->send_seq) {
 888                 *bufp++ = htons(session->ns);
 889                 *bufp++ = 0;
 890                 session->ns++;
 891                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 892                        "%s: updated ns to %hu\n", session->name, session->ns);
 893         }
 894 }
 895
 896 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
 897  * when a user application does a sendmsg() on the session socket. L2TP and
 898  * PPP headers must be inserted into the user's data.
 899  */
 900 static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
 901                             size_t total_len)
 902 {
 903         static const unsigned char ppph[2] = { 0xff, 0x03 };
 904         struct sock *sk = sock->sk;
 905         struct inet_sock *inet;
 906         __wsum csum;
 907         struct sk_buff *skb;
 908         int error;
 909         int hdr_len;
 910         struct pppol2tp_session *session;
 911         struct pppol2tp_tunnel *tunnel;
 912         struct udphdr *uh;
 913         unsigned int len;
 914         struct sock *sk_tun;
 915         u16 udp_len;
 916
 917         error = -ENOTCONN;
 918         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 919                 goto error;
 920
 921         /* Get session and tunnel contexts */
 922         error = -EBADF;
 923         session = pppol2tp_sock_to_session(sk);
 924         if (session == NULL)
 925                 goto error;
 926
 927         sk_tun = session->tunnel_sock;
 928         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
 929         if (tunnel == NULL)
 930                 goto error_put_sess;
 931
 932         /* What header length is configured for this session? */
 933         hdr_len = pppol2tp_l2tp_header_len(session);
 934
 935         /* Allocate a socket buffer */
 936         error = -ENOMEM;
 937         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
 938                            sizeof(struct udphdr) + hdr_len +
 939                            sizeof(ppph) + total_len,
 940                            0, GFP_KERNEL);
 941         if (!skb)
 942                 goto error_put_sess_tun;
 943
 944         /* Reserve space for headers. */
 945         skb_reserve(skb, NET_SKB_PAD);
 946         skb_reset_network_header(skb);
 947         skb_reserve(skb, sizeof(struct iphdr));
 948         skb_reset_transport_header(skb);
 949
 950         /* Build UDP header */
 951         inet = inet_sk(sk_tun);
 952         udp_len = hdr_len + sizeof(ppph) + total_len;
 953         uh = (struct udphdr *) skb->data;
 954         uh->source = inet->inet_sport;
 955         uh->dest = inet->inet_dport;
 956         uh->len = htons(udp_len);
 957         uh->check = 0;
 958         skb_put(skb, sizeof(struct udphdr));
 959
 960         /* Build L2TP header */
 961         pppol2tp_build_l2tp_header(session, skb->data);
 962         skb_put(skb, hdr_len);
 963
 964         /* Add PPP header */
 965         skb->data[0] = ppph[0];
 966         skb->data[1] = ppph[1];
 967         skb_put(skb, 2);
 968
 969         /* Copy user data into skb */
 970         error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
 971         if (error < 0) {
 972                 kfree_skb(skb);
 973                 goto error_put_sess_tun;
 974         }
 975         skb_put(skb, total_len);
 976
 977         /* Calculate UDP checksum if configured to do so */
 978         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
 979                 skb->ip_summed = CHECKSUM_NONE;
 980         else if (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
 981                 skb->ip_summed = CHECKSUM_COMPLETE;
 982                 csum = skb_checksum(skb, 0, udp_len, 0);
 983                 uh->check = csum_tcpudp_magic(inet->inet_saddr,
 984                                               inet->inet_daddr,
 985                                               udp_len, IPPROTO_UDP, csum);
 986                 if (uh->check == 0)
 987                         uh->check = CSUM_MANGLED_0;
 988         } else {
 989                 skb->ip_summed = CHECKSUM_PARTIAL;
 990                 skb->csum_start = skb_transport_header(skb) - skb->head;
 991                 skb->csum_offset = offsetof(struct udphdr, check);
 992                 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
 993                                                inet->inet_daddr,
 994                                                udp_len, IPPROTO_UDP, 0);
 995         }
 996
 997         /* Debug */
 998         if (session->send_seq)
 999                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1000                        "%s: send %Zd bytes, ns=%hu\n", session->name,
1001                        total_len, session->ns - 1);
1002         else
1003                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1004                        "%s: send %Zd bytes\n", session->name, total_len);
1005
1006         if (session->debug & PPPOL2TP_MSG_DATA) {
1007                 int i;
1008                 unsigned char *datap = skb->data;
1009
1010                 printk(KERN_DEBUG "%s: xmit:", session->name);
1011                 for (i = 0; i < total_len; i++) {
1012                         printk(" %02X", *datap++);
1013                         if (i == 15) {
1014                                 printk(" ...");
1015                                 break;
1016                         }
1017                 }
1018                 printk("\n");
1019         }
1020
1021         /* Queue the packet to IP for output */
1022         len = skb->len;
1023         error = ip_queue_xmit(skb, 1);
1024
1025         /* Update stats */
1026         if (error >= 0) {
1027                 tunnel->stats.tx_packets++;
1028                 tunnel->stats.tx_bytes += len;
1029                 session->stats.tx_packets++;
1030                 session->stats.tx_bytes += len;
1031         } else {
1032                 tunnel->stats.tx_errors++;
1033                 session->stats.tx_errors++;
1034         }
1035
1036         return error;
1037
1038 error_put_sess_tun:
1039         sock_put(session->tunnel_sock);
1040 error_put_sess:
1041         sock_put(sk);
1042 error:
1043         return error;
1044 }
1045
1046 /* Automatically called when the skb is freed.
1047  */
1048 static void pppol2tp_sock_wfree(struct sk_buff *skb)
1049 {
1050         sock_put(skb->sk);
1051 }
1052
1053 /* For data skbs that we transmit, we associate with the tunnel socket
1054  * but don't do accounting.
1055  */
1056 static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1057 {
1058         sock_hold(sk);
1059         skb->sk = sk;
1060         skb->destructor = pppol2tp_sock_wfree;
1061 }
1062
1063 /* Transmit function called by generic PPP driver.  Sends PPP frame
1064  * over PPPoL2TP socket.
1065  *
1066  * This is almost the same as pppol2tp_sendmsg(), but rather than
1067  * being called with a msghdr from userspace, it is called with a skb
1068  * from the kernel.
1069  *
1070  * The supplied skb from ppp doesn't have enough headroom for the
1071  * insertion of L2TP, UDP and IP headers so we need to allocate more
1072  * headroom in the skb. This will create a cloned skb. But we must be
1073  * careful in the error case because the caller will expect to free
1074  * the skb it supplied, not our cloned skb. So we take care to always
1075  * leave the original skb unfreed if we return an error.
1076  */
1077 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
1078 {
1079         static const u8 ppph[2] = { 0xff, 0x03 };
1080         struct sock *sk = (struct sock *) chan->private;
1081         struct sock *sk_tun;
1082         int hdr_len;
1083         u16 udp_len;
1084         struct pppol2tp_session *session;
1085         struct pppol2tp_tunnel *tunnel;
1086         int rc;
1087         int headroom;
1088         int data_len = skb->len;
1089         struct inet_sock *inet;
1090         __wsum csum;
1091         struct udphdr *uh;
1092         unsigned int len;
1093         int old_headroom;
1094         int new_headroom;
1095
1096         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
1097                 goto abort;
1098
1099         /* Get session and tunnel contexts from the socket */
1100         session = pppol2tp_sock_to_session(sk);
1101         if (session == NULL)
1102                 goto abort;
1103
1104         sk_tun = session->tunnel_sock;
1105         if (sk_tun == NULL)
1106                 goto abort_put_sess;
1107         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
1108         if (tunnel == NULL)
1109                 goto abort_put_sess;
1110
1111         /* What header length is configured for this session? */
1112         hdr_len = pppol2tp_l2tp_header_len(session);
1113
1114         /* Check that there's enough headroom in the skb to insert IP,
1115          * UDP and L2TP and PPP headers. If not enough, expand it to
1116          * make room. Adjust truesize.
1117          */
1118         headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1119                 sizeof(struct udphdr) + hdr_len + sizeof(ppph);
1120         old_headroom = skb_headroom(skb);
1121         if (skb_cow_head(skb, headroom))
1122                 goto abort_put_sess_tun;
1123
1124         new_headroom = skb_headroom(skb);
1125         skb_orphan(skb);
1126         skb->truesize += new_headroom - old_headroom;
1127
1128         /* Setup PPP header */
1129         __skb_push(skb, sizeof(ppph));
1130         skb->data[0] = ppph[0];
1131         skb->data[1] = ppph[1];
1132
1133         /* Setup L2TP header */
1134         pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
1135
1136         udp_len = sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len;
1137
1138         /* Setup UDP header */
1139         inet = inet_sk(sk_tun);
1140         __skb_push(skb, sizeof(*uh));
1141         skb_reset_transport_header(skb);
1142         uh = udp_hdr(skb);
1143         uh->source = inet->inet_sport;
1144         uh->dest = inet->inet_dport;
1145         uh->len = htons(udp_len);
1146         uh->check = 0;
1147
1148         /* Debug */
1149         if (session->send_seq)
1150                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1151                        "%s: send %d bytes, ns=%hu\n", session->name,
1152                        data_len, session->ns - 1);
1153         else
1154                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1155                        "%s: send %d bytes\n", session->name, data_len);
1156
1157         if (session->debug & PPPOL2TP_MSG_DATA) {
1158                 int i;
1159                 unsigned char *datap = skb->data;
1160
1161                 printk(KERN_DEBUG "%s: xmit:", session->name);
1162                 for (i = 0; i < data_len; i++) {
1163                         printk(" %02X", *datap++);
1164                         if (i == 31) {
1165                                 printk(" ...");
1166                                 break;
1167                         }
1168                 }
1169                 printk("\n");
1170         }
1171
1172         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1173         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1174                               IPSKB_REROUTED);
1175         nf_reset(skb);
1176
1177         /* Get routing info from the tunnel socket */
1178         skb_dst_drop(skb);
1179         skb_dst_set(skb, dst_clone(__sk_dst_get(sk_tun)));
1180         pppol2tp_skb_set_owner_w(skb, sk_tun);
1181
1182         /* Calculate UDP checksum if configured to do so */
1183         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
1184                 skb->ip_summed = CHECKSUM_NONE;
1185         else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1186                  (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1187                 skb->ip_summed = CHECKSUM_COMPLETE;
1188                 csum = skb_checksum(skb, 0, udp_len, 0);
1189                 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1190                                               inet->inet_daddr,
1191                                               udp_len, IPPROTO_UDP, csum);
1192                 if (uh->check == 0)
1193                         uh->check = CSUM_MANGLED_0;
1194         } else {
1195                 skb->ip_summed = CHECKSUM_PARTIAL;
1196                 skb->csum_start = skb_transport_header(skb) - skb->head;
1197                 skb->csum_offset = offsetof(struct udphdr, check);
1198                 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1199                                                inet->inet_daddr,
1200                                                udp_len, IPPROTO_UDP, 0);
1201         }
1202
1203         /* Queue the packet to IP for output */
1204         len = skb->len;
1205         rc = ip_queue_xmit(skb, 1);
1206
1207         /* Update stats */
1208         if (rc >= 0) {
1209                 tunnel->stats.tx_packets++;
1210                 tunnel->stats.tx_bytes += len;
1211                 session->stats.tx_packets++;
1212                 session->stats.tx_bytes += len;
1213         } else {
1214                 tunnel->stats.tx_errors++;
1215                 session->stats.tx_errors++;
1216         }
1217
1218         sock_put(sk_tun);
1219         sock_put(sk);
1220         return 1;
1221
1222 abort_put_sess_tun:
1223         sock_put(sk_tun);
1224 abort_put_sess:
1225         sock_put(sk);
1226 abort:
1227         /* Free the original skb */
1228         kfree_skb(skb);
1229         return 1;
1230 }
1231
1232 /*****************************************************************************
1233  * Session (and tunnel control) socket create/destroy.
1234  *****************************************************************************/
1235
1236 /* When the tunnel UDP socket is closed, all the attached sockets need to go
1237  * too.
1238  */
1239 static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel)
1240 {
1241         int hash;
1242         struct hlist_node *walk;
1243         struct hlist_node *tmp;
1244         struct pppol2tp_session *session;
1245         struct sock *sk;
1246
1247         BUG_ON(tunnel == NULL);
1248
1249         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1250                "%s: closing all sessions...\n", tunnel->name);
1251
1252         write_lock_bh(&tunnel->hlist_lock);
1253         for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) {
1254 again:
1255                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1256                         struct sk_buff *skb;
1257
1258                         session = hlist_entry(walk, struct pppol2tp_session, hlist);
1259
1260                         sk = session->sock;
1261
1262                         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1263                                "%s: closing session\n", session->name);
1264
1265                         hlist_del_init(&session->hlist);
1266
1267                         /* Since we should hold the sock lock while
1268                          * doing any unbinding, we need to release the
1269                          * lock we're holding before taking that lock.
1270                          * Hold a reference to the sock so it doesn't
1271                          * disappear as we're jumping between locks.
1272                          */
1273                         sock_hold(sk);
1274                         write_unlock_bh(&tunnel->hlist_lock);
1275                         lock_sock(sk);
1276
1277                         if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
1278                                 pppox_unbind_sock(sk);
1279                                 sk->sk_state = PPPOX_DEAD;
1280                                 sk->sk_state_change(sk);
1281                         }
1282
1283                         /* Purge any queued data */
1284                         skb_queue_purge(&sk->sk_receive_queue);
1285                         skb_queue_purge(&sk->sk_write_queue);
1286                         while ((skb = skb_dequeue(&session->reorder_q))) {
1287                                 kfree_skb(skb);
1288                                 sock_put(sk);
1289                         }
1290
1291                         release_sock(sk);
1292                         sock_put(sk);
1293
1294                         /* Now restart from the beginning of this hash
1295                          * chain.  We always remove a session from the
1296                          * list so we are guaranteed to make forward
1297                          * progress.
1298                          */
1299                         write_lock_bh(&tunnel->hlist_lock);
1300                         goto again;
1301                 }
1302         }
1303         write_unlock_bh(&tunnel->hlist_lock);
1304 }
1305
1306 /* Really kill the tunnel.
1307  * Come here only when all sessions have been cleared from the tunnel.
1308  */
1309 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
1310 {
1311         struct pppol2tp_net *pn = pppol2tp_pernet(tunnel->pppol2tp_net);
1312
1313         /* Remove from socket list */
1314         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1315         list_del_init(&tunnel->list);
1316         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1317
1318         atomic_dec(&pppol2tp_tunnel_count);
1319         kfree(tunnel);
1320 }
1321
1322 /* Tunnel UDP socket destruct hook.
1323  * The tunnel context is deleted only when all session sockets have been
1324  * closed.
1325  */
1326 static void pppol2tp_tunnel_destruct(struct sock *sk)
1327 {
1328         struct pppol2tp_tunnel *tunnel;
1329
1330         tunnel = sk->sk_user_data;
1331         if (tunnel == NULL)
1332                 goto end;
1333
1334         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1335                "%s: closing...\n", tunnel->name);
1336
1337         /* Close all sessions */
1338         pppol2tp_tunnel_closeall(tunnel);
1339
1340         /* No longer an encapsulation socket. See net/ipv4/udp.c */
1341         (udp_sk(sk))->encap_type = 0;
1342         (udp_sk(sk))->encap_rcv = NULL;
1343
1344         /* Remove hooks into tunnel socket */
1345         tunnel->sock = NULL;
1346         sk->sk_destruct = tunnel->old_sk_destruct;
1347         sk->sk_user_data = NULL;
1348
1349         /* Call original (UDP) socket descructor */
1350         if (sk->sk_destruct != NULL)
1351                 (*sk->sk_destruct)(sk);
1352
1353         pppol2tp_tunnel_dec_refcount(tunnel);
1354
1355 end:
1356         return;
1357 }
1358
1359 /* Really kill the session socket. (Called from sock_put() if
1360  * refcnt == 0.)
1361  */
1362 static void pppol2tp_session_destruct(struct sock *sk)
1363 {
1364         struct pppol2tp_session *session = NULL;
1365
1366         if (sk->sk_user_data != NULL) {
1367                 struct pppol2tp_tunnel *tunnel;
1368
1369                 session = sk->sk_user_data;
1370                 if (session == NULL)
1371                         goto out;
1372
1373                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
1374
1375                 /* Don't use pppol2tp_sock_to_tunnel() here to
1376                  * get the tunnel context because the tunnel
1377                  * socket might have already been closed (its
1378                  * sk->sk_user_data will be NULL) so use the
1379                  * session's private tunnel ptr instead.
1380                  */
1381                 tunnel = session->tunnel;
1382                 if (tunnel != NULL) {
1383                         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1384
1385                         /* If session_id is zero, this is a null
1386                          * session context, which was created for a
1387                          * socket that is being used only to manage
1388                          * tunnels.
1389                          */
1390                         if (session->tunnel_addr.s_session != 0) {
1391                                 /* Delete the session socket from the
1392                                  * hash
1393                                  */
1394                                 write_lock_bh(&tunnel->hlist_lock);
1395                                 hlist_del_init(&session->hlist);
1396                                 write_unlock_bh(&tunnel->hlist_lock);
1397
1398                                 atomic_dec(&pppol2tp_session_count);
1399                         }
1400
1401                         /* This will delete the tunnel context if this
1402                          * is the last session on the tunnel.
1403                          */
1404                         session->tunnel = NULL;
1405                         session->tunnel_sock = NULL;
1406                         pppol2tp_tunnel_dec_refcount(tunnel);
1407                 }
1408         }
1409
1410         kfree(session);
1411 out:
1412         return;
1413 }
1414
1415 /* Called when the PPPoX socket (session) is closed.
1416  */
1417 static int pppol2tp_release(struct socket *sock)
1418 {
1419         struct sock *sk = sock->sk;
1420         struct pppol2tp_session *session;
1421         int error;
1422
1423         if (!sk)
1424                 return 0;
1425
1426         error = -EBADF;
1427         lock_sock(sk);
1428         if (sock_flag(sk, SOCK_DEAD) != 0)
1429                 goto error;
1430
1431         pppox_unbind_sock(sk);
1432
1433         /* Signal the death of the socket. */
1434         sk->sk_state = PPPOX_DEAD;
1435         sock_orphan(sk);
1436         sock->sk = NULL;
1437
1438         session = pppol2tp_sock_to_session(sk);
1439
1440         /* Purge any queued data */
1441         skb_queue_purge(&sk->sk_receive_queue);
1442         skb_queue_purge(&sk->sk_write_queue);
1443         if (session != NULL) {
1444                 struct sk_buff *skb;
1445                 while ((skb = skb_dequeue(&session->reorder_q))) {
1446                         kfree_skb(skb);
1447                         sock_put(sk);
1448                 }
1449                 sock_put(sk);
1450         }
1451
1452         release_sock(sk);
1453
1454         /* This will delete the session context via
1455          * pppol2tp_session_destruct() if the socket's refcnt drops to
1456          * zero.
1457          */
1458         sock_put(sk);
1459
1460         return 0;
1461
1462 error:
1463         release_sock(sk);
1464         return error;
1465 }
1466
1467 /* Internal function to prepare a tunnel (UDP) socket to have PPPoX
1468  * sockets attached to it.
1469  */
1470 static struct sock *pppol2tp_prepare_tunnel_socket(struct net *net,
1471                                         int fd, u16 tunnel_id, int *error)
1472 {
1473         int err;
1474         struct socket *sock = NULL;
1475         struct sock *sk;
1476         struct pppol2tp_tunnel *tunnel;
1477         struct pppol2tp_net *pn;
1478         struct sock *ret = NULL;
1479
1480         /* Get the tunnel UDP socket from the fd, which was opened by
1481          * the userspace L2TP daemon.
1482          */
1483         err = -EBADF;
1484         sock = sockfd_lookup(fd, &err);
1485         if (!sock) {
1486                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1487                        "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1488                        tunnel_id, fd, err);
1489                 goto err;
1490         }
1491
1492         sk = sock->sk;
1493
1494         /* Quick sanity checks */
1495         err = -EPROTONOSUPPORT;
1496         if (sk->sk_protocol != IPPROTO_UDP) {
1497                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1498                        "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1499                        tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1500                 goto err;
1501         }
1502         err = -EAFNOSUPPORT;
1503         if (sock->ops->family != AF_INET) {
1504                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1505                        "tunl %hu: fd %d wrong family, got %d, expected %d\n",
1506                        tunnel_id, fd, sock->ops->family, AF_INET);
1507                 goto err;
1508         }
1509
1510         err = -ENOTCONN;
1511
1512         /* Check if this socket has already been prepped */
1513         tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;
1514         if (tunnel != NULL) {
1515                 /* User-data field already set */
1516                 err = -EBUSY;
1517                 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1518
1519                 /* This socket has already been prepped */
1520                 ret = tunnel->sock;
1521                 goto out;
1522         }
1523
1524         /* This socket is available and needs prepping. Create a new tunnel
1525          * context and init it.
1526          */
1527         sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL);
1528         if (sk->sk_user_data == NULL) {
1529                 err = -ENOMEM;
1530                 goto err;
1531         }
1532
1533         tunnel->magic = L2TP_TUNNEL_MAGIC;
1534         sprintf(&tunnel->name[0], "tunl %hu", tunnel_id);
1535
1536         tunnel->stats.tunnel_id = tunnel_id;
1537         tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS;
1538
1539         /* Hook on the tunnel socket destructor so that we can cleanup
1540          * if the tunnel socket goes away.
1541          */
1542         tunnel->old_sk_destruct = sk->sk_destruct;
1543         sk->sk_destruct = pppol2tp_tunnel_destruct;
1544
1545         tunnel->sock = sk;
1546         sk->sk_allocation = GFP_ATOMIC;
1547
1548         /* Misc init */
1549         rwlock_init(&tunnel->hlist_lock);
1550
1551         /* The net we belong to */
1552         tunnel->pppol2tp_net = net;
1553         pn = pppol2tp_pernet(net);
1554
1555         /* Add tunnel to our list */
1556         INIT_LIST_HEAD(&tunnel->list);
1557         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1558         list_add(&tunnel->list, &pn->pppol2tp_tunnel_list);
1559         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1560         atomic_inc(&pppol2tp_tunnel_count);
1561
1562         /* Bump the reference count. The tunnel context is deleted
1563          * only when this drops to zero.
1564          */
1565         pppol2tp_tunnel_inc_refcount(tunnel);
1566
1567         /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1568         (udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP;
1569         (udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv;
1570
1571         ret = tunnel->sock;
1572
1573         *error = 0;
1574 out:
1575         if (sock)
1576                 sockfd_put(sock);
1577
1578         return ret;
1579
1580 err:
1581         *error = err;
1582         goto out;
1583 }
1584
1585 static struct proto pppol2tp_sk_proto = {
1586         .name     = "PPPOL2TP",
1587         .owner    = THIS_MODULE,
1588         .obj_size = sizeof(struct pppox_sock),
1589 };
1590
1591 /* socket() handler. Initialize a new struct sock.
1592  */
1593 static int pppol2tp_create(struct net *net, struct socket *sock)
1594 {
1595         int error = -ENOMEM;
1596         struct sock *sk;
1597
1598         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
1599         if (!sk)
1600                 goto out;
1601
1602         sock_init_data(sock, sk);
1603
1604         sock->state  = SS_UNCONNECTED;
1605         sock->ops    = &pppol2tp_ops;
1606
1607         sk->sk_backlog_rcv = pppol2tp_recv_core;
1608         sk->sk_protocol    = PX_PROTO_OL2TP;
1609         sk->sk_family      = PF_PPPOX;
1610         sk->sk_state       = PPPOX_NONE;
1611         sk->sk_type        = SOCK_STREAM;
1612         sk->sk_destruct    = pppol2tp_session_destruct;
1613
1614         error = 0;
1615
1616 out:
1617         return error;
1618 }
1619
1620 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
1621  */
1622 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
1623                             int sockaddr_len, int flags)
1624 {
1625         struct sock *sk = sock->sk;
1626         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
1627         struct pppox_sock *po = pppox_sk(sk);
1628         struct sock *tunnel_sock = NULL;
1629         struct pppol2tp_session *session = NULL;
1630         struct pppol2tp_tunnel *tunnel;
1631         struct dst_entry *dst;
1632         int error = 0;
1633
1634         lock_sock(sk);
1635
1636         error = -EINVAL;
1637         if (sp->sa_protocol != PX_PROTO_OL2TP)
1638                 goto end;
1639
1640         /* Check for already bound sockets */
1641         error = -EBUSY;
1642         if (sk->sk_state & PPPOX_CONNECTED)
1643                 goto end;
1644
1645         /* We don't supporting rebinding anyway */
1646         error = -EALREADY;
1647         if (sk->sk_user_data)
1648                 goto end; /* socket is already attached */
1649
1650         /* Don't bind if s_tunnel is 0 */
1651         error = -EINVAL;
1652         if (sp->pppol2tp.s_tunnel == 0)
1653                 goto end;
1654
1655         /* Special case: prepare tunnel socket if s_session and
1656          * d_session is 0. Otherwise look up tunnel using supplied
1657          * tunnel id.
1658          */
1659         if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
1660                 tunnel_sock = pppol2tp_prepare_tunnel_socket(sock_net(sk),
1661                                                              sp->pppol2tp.fd,
1662                                                              sp->pppol2tp.s_tunnel,
1663                                                              &error);
1664                 if (tunnel_sock == NULL)
1665                         goto end;
1666
1667                 sock_hold(tunnel_sock);
1668                 tunnel = tunnel_sock->sk_user_data;
1669         } else {
1670                 tunnel = pppol2tp_tunnel_find(sock_net(sk), sp->pppol2tp.s_tunnel);
1671
1672                 /* Error if we can't find the tunnel */
1673                 error = -ENOENT;
1674                 if (tunnel == NULL)
1675                         goto end;
1676
1677                 tunnel_sock = tunnel->sock;
1678         }
1679
1680         /* Check that this session doesn't already exist */
1681         error = -EEXIST;
1682         session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session);
1683         if (session != NULL)
1684                 goto end;
1685
1686         /* Allocate and initialize a new session context. */
1687         session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL);
1688         if (session == NULL) {
1689                 error = -ENOMEM;
1690                 goto end;
1691         }
1692
1693         skb_queue_head_init(&session->reorder_q);
1694
1695         session->magic       = L2TP_SESSION_MAGIC;
1696         session->owner       = current->pid;
1697         session->sock        = sk;
1698         session->tunnel      = tunnel;
1699         session->tunnel_sock = tunnel_sock;
1700         session->tunnel_addr = sp->pppol2tp;
1701         sprintf(&session->name[0], "sess %hu/%hu",
1702                 session->tunnel_addr.s_tunnel,
1703                 session->tunnel_addr.s_session);
1704
1705         session->stats.tunnel_id  = session->tunnel_addr.s_tunnel;
1706         session->stats.session_id = session->tunnel_addr.s_session;
1707
1708         INIT_HLIST_NODE(&session->hlist);
1709
1710         /* Inherit debug options from tunnel */
1711         session->debug = tunnel->debug;
1712
1713         /* Default MTU must allow space for UDP/L2TP/PPP
1714          * headers.
1715          */
1716         session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
1717
1718         /* If PMTU discovery was enabled, use the MTU that was discovered */
1719         dst = sk_dst_get(sk);
1720         if (dst != NULL) {
1721                 u32 pmtu = dst_mtu(__sk_dst_get(sk));
1722                 if (pmtu != 0)
1723                         session->mtu = session->mru = pmtu -
1724                                 PPPOL2TP_HEADER_OVERHEAD;
1725                 dst_release(dst);
1726         }
1727
1728         /* Special case: if source & dest session_id == 0x0000, this socket is
1729          * being created to manage the tunnel. Don't add the session to the
1730          * session hash list, just set up the internal context for use by
1731          * ioctl() and sockopt() handlers.
1732          */
1733         if ((session->tunnel_addr.s_session == 0) &&
1734             (session->tunnel_addr.d_session == 0)) {
1735                 error = 0;
1736                 sk->sk_user_data = session;
1737                 goto out_no_ppp;
1738         }
1739
1740         /* Get tunnel context from the tunnel socket */
1741         tunnel = pppol2tp_sock_to_tunnel(tunnel_sock);
1742         if (tunnel == NULL) {
1743                 error = -EBADF;
1744                 goto end;
1745         }
1746
1747         /* Right now, because we don't have a way to push the incoming skb's
1748          * straight through the UDP layer, the only header we need to worry
1749          * about is the L2TP header. This size is different depending on
1750          * whether sequence numbers are enabled for the data channel.
1751          */
1752         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1753
1754         po->chan.private = sk;
1755         po->chan.ops     = &pppol2tp_chan_ops;
1756         po->chan.mtu     = session->mtu;
1757
1758         error = ppp_register_net_channel(sock_net(sk), &po->chan);
1759         if (error)
1760                 goto end_put_tun;
1761
1762         /* This is how we get the session context from the socket. */
1763         sk->sk_user_data = session;
1764
1765         /* Add session to the tunnel's hash list */
1766         write_lock_bh(&tunnel->hlist_lock);
1767         hlist_add_head(&session->hlist,
1768                        pppol2tp_session_id_hash(tunnel,
1769                                                 session->tunnel_addr.s_session));
1770         write_unlock_bh(&tunnel->hlist_lock);
1771
1772         atomic_inc(&pppol2tp_session_count);
1773
1774 out_no_ppp:
1775         pppol2tp_tunnel_inc_refcount(tunnel);
1776         sk->sk_state = PPPOX_CONNECTED;
1777         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1778                "%s: created\n", session->name);
1779
1780 end_put_tun:
1781         sock_put(tunnel_sock);
1782 end:
1783         release_sock(sk);
1784
1785         if (error != 0) {
1786                 if (session)
1787                         PRINTK(session->debug,
1788                                 PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1789                                 "%s: connect failed: %d\n",
1790                                 session->name, error);
1791                 else
1792                         PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1793                                 "connect failed: %d\n", error);
1794         }
1795
1796         return error;
1797 }
1798
1799 /* getname() support.
1800  */
1801 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
1802                             int *usockaddr_len, int peer)
1803 {
1804         int len = sizeof(struct sockaddr_pppol2tp);
1805         struct sockaddr_pppol2tp sp;
1806         int error = 0;
1807         struct pppol2tp_session *session;
1808
1809         error = -ENOTCONN;
1810         if (sock->sk->sk_state != PPPOX_CONNECTED)
1811                 goto end;
1812
1813         session = pppol2tp_sock_to_session(sock->sk);
1814         if (session == NULL) {
1815                 error = -EBADF;
1816                 goto end;
1817         }
1818
1819         sp.sa_family    = AF_PPPOX;
1820         sp.sa_protocol  = PX_PROTO_OL2TP;
1821         memcpy(&sp.pppol2tp, &session->tunnel_addr,
1822                sizeof(struct pppol2tp_addr));
1823
1824         memcpy(uaddr, &sp, len);
1825
1826         *usockaddr_len = len;
1827
1828         error = 0;
1829         sock_put(sock->sk);
1830
1831 end:
1832         return error;
1833 }
1834
1835 /****************************************************************************
1836  * ioctl() handlers.
1837  *
1838  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1839  * sockets. However, in order to control kernel tunnel features, we allow
1840  * userspace to create a special "tunnel" PPPoX socket which is used for
1841  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
1842  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1843  * calls.
1844  ****************************************************************************/
1845
1846 /* Session ioctl helper.
1847  */
1848 static int pppol2tp_session_ioctl(struct pppol2tp_session *session,
1849                                   unsigned int cmd, unsigned long arg)
1850 {
1851         struct ifreq ifr;
1852         int err = 0;
1853         struct sock *sk = session->sock;
1854         int val = (int) arg;
1855
1856         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1857                "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1858                session->name, cmd, arg);
1859
1860         sock_hold(sk);
1861
1862         switch (cmd) {
1863         case SIOCGIFMTU:
1864                 err = -ENXIO;
1865                 if (!(sk->sk_state & PPPOX_CONNECTED))
1866                         break;
1867
1868                 err = -EFAULT;
1869                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1870                         break;
1871                 ifr.ifr_mtu = session->mtu;
1872                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1873                         break;
1874
1875                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1876                        "%s: get mtu=%d\n", session->name, session->mtu);
1877                 err = 0;
1878                 break;
1879
1880         case SIOCSIFMTU:
1881                 err = -ENXIO;
1882                 if (!(sk->sk_state & PPPOX_CONNECTED))
1883                         break;
1884
1885                 err = -EFAULT;
1886                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1887                         break;
1888
1889                 session->mtu = ifr.ifr_mtu;
1890
1891                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1892                        "%s: set mtu=%d\n", session->name, session->mtu);
1893                 err = 0;
1894                 break;
1895
1896         case PPPIOCGMRU:
1897                 err = -ENXIO;
1898                 if (!(sk->sk_state & PPPOX_CONNECTED))
1899                         break;
1900
1901                 err = -EFAULT;
1902                 if (put_user(session->mru, (int __user *) arg))
1903                         break;
1904
1905                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1906                        "%s: get mru=%d\n", session->name, session->mru);
1907                 err = 0;
1908                 break;
1909
1910         case PPPIOCSMRU:
1911                 err = -ENXIO;
1912                 if (!(sk->sk_state & PPPOX_CONNECTED))
1913                         break;
1914
1915                 err = -EFAULT;
1916                 if (get_user(val,(int __user *) arg))
1917                         break;
1918
1919                 session->mru = val;
1920                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1921                        "%s: set mru=%d\n", session->name, session->mru);
1922                 err = 0;
1923                 break;
1924
1925         case PPPIOCGFLAGS:
1926                 err = -EFAULT;
1927                 if (put_user(session->flags, (int __user *) arg))
1928                         break;
1929
1930                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1931                        "%s: get flags=%d\n", session->name, session->flags);
1932                 err = 0;
1933                 break;
1934
1935         case PPPIOCSFLAGS:
1936                 err = -EFAULT;
1937                 if (get_user(val, (int __user *) arg))
1938                         break;
1939                 session->flags = val;
1940                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1941                        "%s: set flags=%d\n", session->name, session->flags);
1942                 err = 0;
1943                 break;
1944
1945         case PPPIOCGL2TPSTATS:
1946                 err = -ENXIO;
1947                 if (!(sk->sk_state & PPPOX_CONNECTED))
1948                         break;
1949
1950                 if (copy_to_user((void __user *) arg, &session->stats,
1951                                  sizeof(session->stats)))
1952                         break;
1953                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1954                        "%s: get L2TP stats\n", session->name);
1955                 err = 0;
1956                 break;
1957
1958         default:
1959                 err = -ENOSYS;
1960                 break;
1961         }
1962
1963         sock_put(sk);
1964
1965         return err;
1966 }
1967
1968 /* Tunnel ioctl helper.
1969  *
1970  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1971  * specifies a session_id, the session ioctl handler is called. This allows an
1972  * application to retrieve session stats via a tunnel socket.
1973  */
1974 static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel,
1975                                  unsigned int cmd, unsigned long arg)
1976 {
1977         int err = 0;
1978         struct sock *sk = tunnel->sock;
1979         struct pppol2tp_ioc_stats stats_req;
1980
1981         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1982                "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name,
1983                cmd, arg);
1984
1985         sock_hold(sk);
1986
1987         switch (cmd) {
1988         case PPPIOCGL2TPSTATS:
1989                 err = -ENXIO;
1990                 if (!(sk->sk_state & PPPOX_CONNECTED))
1991                         break;
1992
1993                 if (copy_from_user(&stats_req, (void __user *) arg,
1994                                    sizeof(stats_req))) {
1995                         err = -EFAULT;
1996                         break;
1997                 }
1998                 if (stats_req.session_id != 0) {
1999                         /* resend to session ioctl handler */
2000                         struct pppol2tp_session *session =
2001                                 pppol2tp_session_find(tunnel, stats_req.session_id);
2002                         if (session != NULL)
2003                                 err = pppol2tp_session_ioctl(session, cmd, arg);
2004                         else
2005                                 err = -EBADR;
2006                         break;
2007                 }
2008 #ifdef CONFIG_XFRM
2009                 tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
2010 #endif
2011                 if (copy_to_user((void __user *) arg, &tunnel->stats,
2012                                  sizeof(tunnel->stats))) {
2013                         err = -EFAULT;
2014                         break;
2015                 }
2016                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2017                        "%s: get L2TP stats\n", tunnel->name);
2018                 err = 0;
2019                 break;
2020
2021         default:
2022                 err = -ENOSYS;
2023                 break;
2024         }
2025
2026         sock_put(sk);
2027
2028         return err;
2029 }
2030
2031 /* Main ioctl() handler.
2032  * Dispatch to tunnel or session helpers depending on the socket.
2033  */
2034 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
2035                           unsigned long arg)
2036 {
2037         struct sock *sk = sock->sk;
2038         struct pppol2tp_session *session;
2039         struct pppol2tp_tunnel *tunnel;
2040         int err;
2041
2042         if (!sk)
2043                 return 0;
2044
2045         err = -EBADF;
2046         if (sock_flag(sk, SOCK_DEAD) != 0)
2047                 goto end;
2048
2049         err = -ENOTCONN;
2050         if ((sk->sk_user_data == NULL) ||
2051             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
2052                 goto end;
2053
2054         /* Get session context from the socket */
2055         err = -EBADF;
2056         session = pppol2tp_sock_to_session(sk);
2057         if (session == NULL)
2058                 goto end;
2059
2060         /* Special case: if session's session_id is zero, treat ioctl as a
2061          * tunnel ioctl
2062          */
2063         if ((session->tunnel_addr.s_session == 0) &&
2064             (session->tunnel_addr.d_session == 0)) {
2065                 err = -EBADF;
2066                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2067                 if (tunnel == NULL)
2068                         goto end_put_sess;
2069
2070                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
2071                 sock_put(session->tunnel_sock);
2072                 goto end_put_sess;
2073         }
2074
2075         err = pppol2tp_session_ioctl(session, cmd, arg);
2076
2077 end_put_sess:
2078         sock_put(sk);
2079 end:
2080         return err;
2081 }
2082
2083 /*****************************************************************************
2084  * setsockopt() / getsockopt() support.
2085  *
2086  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
2087  * sockets. In order to control kernel tunnel features, we allow userspace to
2088  * create a special "tunnel" PPPoX socket which is used for control only.
2089  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
2090  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
2091  *****************************************************************************/
2092
2093 /* Tunnel setsockopt() helper.
2094  */
2095 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
2096                                       struct pppol2tp_tunnel *tunnel,
2097                                       int optname, int val)
2098 {
2099         int err = 0;
2100
2101         switch (optname) {
2102         case PPPOL2TP_SO_DEBUG:
2103                 tunnel->debug = val;
2104                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2105                        "%s: set debug=%x\n", tunnel->name, tunnel->debug);
2106                 break;
2107
2108         default:
2109                 err = -ENOPROTOOPT;
2110                 break;
2111         }
2112
2113         return err;
2114 }
2115
2116 /* Session setsockopt helper.
2117  */
2118 static int pppol2tp_session_setsockopt(struct sock *sk,
2119                                        struct pppol2tp_session *session,
2120                                        int optname, int val)
2121 {
2122         int err = 0;
2123
2124         switch (optname) {
2125         case PPPOL2TP_SO_RECVSEQ:
2126                 if ((val != 0) && (val != 1)) {
2127                         err = -EINVAL;
2128                         break;
2129                 }
2130                 session->recv_seq = val ? -1 : 0;
2131                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2132                        "%s: set recv_seq=%d\n", session->name,
2133                        session->recv_seq);
2134                 break;
2135
2136         case PPPOL2TP_SO_SENDSEQ:
2137                 if ((val != 0) && (val != 1)) {
2138                         err = -EINVAL;
2139                         break;
2140                 }
2141                 session->send_seq = val ? -1 : 0;
2142                 {
2143                         struct sock *ssk      = session->sock;
2144                         struct pppox_sock *po = pppox_sk(ssk);
2145                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
2146                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
2147                 }
2148                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2149                        "%s: set send_seq=%d\n", session->name, session->send_seq);
2150                 break;
2151
2152         case PPPOL2TP_SO_LNSMODE:
2153                 if ((val != 0) && (val != 1)) {
2154                         err = -EINVAL;
2155                         break;
2156                 }
2157                 session->lns_mode = val ? -1 : 0;
2158                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2159                        "%s: set lns_mode=%d\n", session->name,
2160                        session->lns_mode);
2161                 break;
2162
2163         case PPPOL2TP_SO_DEBUG:
2164                 session->debug = val;
2165                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2166                        "%s: set debug=%x\n", session->name, session->debug);
2167                 break;
2168
2169         case PPPOL2TP_SO_REORDERTO:
2170                 session->reorder_timeout = msecs_to_jiffies(val);
2171                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2172                        "%s: set reorder_timeout=%d\n", session->name,
2173                        session->reorder_timeout);
2174                 break;
2175
2176         default:
2177                 err = -ENOPROTOOPT;
2178                 break;
2179         }
2180
2181         return err;
2182 }
2183
2184 /* Main setsockopt() entry point.
2185  * Does API checks, then calls either the tunnel or session setsockopt
2186  * handler, according to whether the PPPoL2TP socket is a for a regular
2187  * session or the special tunnel type.
2188  */
2189 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
2190                                char __user *optval, unsigned int optlen)
2191 {
2192         struct sock *sk = sock->sk;
2193         struct pppol2tp_session *session = sk->sk_user_data;
2194         struct pppol2tp_tunnel *tunnel;
2195         int val;
2196         int err;
2197
2198         if (level != SOL_PPPOL2TP)
2199                 return udp_prot.setsockopt(sk, level, optname, optval, optlen);
2200
2201         if (optlen < sizeof(int))
2202                 return -EINVAL;
2203
2204         if (get_user(val, (int __user *)optval))
2205                 return -EFAULT;
2206
2207         err = -ENOTCONN;
2208         if (sk->sk_user_data == NULL)
2209                 goto end;
2210
2211         /* Get session context from the socket */
2212         err = -EBADF;
2213         session = pppol2tp_sock_to_session(sk);
2214         if (session == NULL)
2215                 goto end;
2216
2217         /* Special case: if session_id == 0x0000, treat as operation on tunnel
2218          */
2219         if ((session->tunnel_addr.s_session == 0) &&
2220             (session->tunnel_addr.d_session == 0)) {
2221                 err = -EBADF;
2222                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2223                 if (tunnel == NULL)
2224                         goto end_put_sess;
2225
2226                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
2227                 sock_put(session->tunnel_sock);
2228         } else
2229                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
2230
2231         err = 0;
2232
2233 end_put_sess:
2234         sock_put(sk);
2235 end:
2236         return err;
2237 }
2238
2239 /* Tunnel getsockopt helper. Called with sock locked.
2240  */
2241 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
2242                                       struct pppol2tp_tunnel *tunnel,
2243                                       int optname, int *val)
2244 {
2245         int err = 0;
2246
2247         switch (optname) {
2248         case PPPOL2TP_SO_DEBUG:
2249                 *val = tunnel->debug;
2250                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2251                        "%s: get debug=%x\n", tunnel->name, tunnel->debug);
2252                 break;
2253
2254         default:
2255                 err = -ENOPROTOOPT;
2256                 break;
2257         }
2258
2259         return err;
2260 }
2261
2262 /* Session getsockopt helper. Called with sock locked.
2263  */
2264 static int pppol2tp_session_getsockopt(struct sock *sk,
2265                                        struct pppol2tp_session *session,
2266                                        int optname, int *val)
2267 {
2268         int err = 0;
2269
2270         switch (optname) {
2271         case PPPOL2TP_SO_RECVSEQ:
2272                 *val = session->recv_seq;
2273                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2274                        "%s: get recv_seq=%d\n", session->name, *val);
2275                 break;
2276
2277         case PPPOL2TP_SO_SENDSEQ:
2278                 *val = session->send_seq;
2279                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2280                        "%s: get send_seq=%d\n", session->name, *val);
2281                 break;
2282
2283         case PPPOL2TP_SO_LNSMODE:
2284                 *val = session->lns_mode;
2285                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2286                        "%s: get lns_mode=%d\n", session->name, *val);
2287                 break;
2288
2289         case PPPOL2TP_SO_DEBUG:
2290                 *val = session->debug;
2291                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2292                        "%s: get debug=%d\n", session->name, *val);
2293                 break;
2294
2295         case PPPOL2TP_SO_REORDERTO:
2296                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
2297                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2298                        "%s: get reorder_timeout=%d\n", session->name, *val);
2299                 break;
2300
2301         default:
2302                 err = -ENOPROTOOPT;
2303         }
2304
2305         return err;
2306 }
2307
2308 /* Main getsockopt() entry point.
2309  * Does API checks, then calls either the tunnel or session getsockopt
2310  * handler, according to whether the PPPoX socket is a for a regular session
2311  * or the special tunnel type.
2312  */
2313 static int pppol2tp_getsockopt(struct socket *sock, int level,
2314                                int optname, char __user *optval, int __user *optlen)
2315 {
2316         struct sock *sk = sock->sk;
2317         struct pppol2tp_session *session = sk->sk_user_data;
2318         struct pppol2tp_tunnel *tunnel;
2319         int val, len;
2320         int err;
2321
2322         if (level != SOL_PPPOL2TP)
2323                 return udp_prot.getsockopt(sk, level, optname, optval, optlen);
2324
2325         if (get_user(len, (int __user *) optlen))
2326                 return -EFAULT;
2327
2328         len = min_t(unsigned int, len, sizeof(int));
2329
2330         if (len < 0)
2331                 return -EINVAL;
2332
2333         err = -ENOTCONN;
2334         if (sk->sk_user_data == NULL)
2335                 goto end;
2336
2337         /* Get the session context */
2338         err = -EBADF;
2339         session = pppol2tp_sock_to_session(sk);
2340         if (session == NULL)
2341                 goto end;
2342
2343         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
2344         if ((session->tunnel_addr.s_session == 0) &&
2345             (session->tunnel_addr.d_session == 0)) {
2346                 err = -EBADF;
2347                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2348                 if (tunnel == NULL)
2349                         goto end_put_sess;
2350
2351                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
2352                 sock_put(session->tunnel_sock);
2353         } else
2354                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
2355
2356         err = -EFAULT;
2357         if (put_user(len, (int __user *) optlen))
2358                 goto end_put_sess;
2359
2360         if (copy_to_user((void __user *) optval, &val, len))
2361                 goto end_put_sess;
2362
2363         err = 0;
2364
2365 end_put_sess:
2366         sock_put(sk);
2367 end:
2368         return err;
2369 }
2370
2371 /*****************************************************************************
2372  * /proc filesystem for debug
2373  *****************************************************************************/
2374
2375 #ifdef CONFIG_PROC_FS
2376
2377 #include <linux/seq_file.h>
2378
2379 struct pppol2tp_seq_data {
2380         struct seq_net_private p;
2381         struct pppol2tp_tunnel *tunnel;         /* current tunnel */
2382         struct pppol2tp_session *session;       /* NULL means get first session in tunnel */
2383 };
2384
2385 static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
2386 {
2387         struct pppol2tp_session *session = NULL;
2388         struct hlist_node *walk;
2389         int found = 0;
2390         int next = 0;
2391         int i;
2392
2393         read_lock_bh(&tunnel->hlist_lock);
2394         for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) {
2395                 hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) {
2396                         if (curr == NULL) {
2397                                 found = 1;
2398                                 goto out;
2399                         }
2400                         if (session == curr) {
2401                                 next = 1;
2402                                 continue;
2403                         }
2404                         if (next) {
2405                                 found = 1;
2406                                 goto out;
2407                         }
2408                 }
2409         }
2410 out:
2411         read_unlock_bh(&tunnel->hlist_lock);
2412         if (!found)
2413                 session = NULL;
2414
2415         return session;
2416 }
2417
2418 static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_net *pn,
2419                                            struct pppol2tp_tunnel *curr)
2420 {
2421         struct pppol2tp_tunnel *tunnel = NULL;
2422
2423         read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
2424         if (list_is_last(&curr->list, &pn->pppol2tp_tunnel_list)) {
2425                 goto out;
2426         }
2427         tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
2428 out:
2429         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
2430
2431         return tunnel;
2432 }
2433
2434 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
2435 {
2436         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
2437         struct pppol2tp_net *pn;
2438         loff_t pos = *offs;
2439
2440         if (!pos)
2441                 goto out;
2442
2443         BUG_ON(m->private == NULL);
2444         pd = m->private;
2445         pn = pppol2tp_pernet(seq_file_net(m));
2446
2447         if (pd->tunnel == NULL) {
2448                 if (!list_empty(&pn->pppol2tp_tunnel_list))
2449                         pd->tunnel = list_entry(pn->pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
2450         } else {
2451                 pd->session = next_session(pd->tunnel, pd->session);
2452                 if (pd->session == NULL) {
2453                         pd->tunnel = next_tunnel(pn, pd->tunnel);
2454                 }
2455         }
2456
2457         /* NULL tunnel and session indicates end of list */
2458         if ((pd->tunnel == NULL) && (pd->session == NULL))
2459                 pd = NULL;
2460
2461 out:
2462         return pd;
2463 }
2464
2465 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
2466 {
2467         (*pos)++;
2468         return NULL;
2469 }
2470
2471 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
2472 {
2473         /* nothing to do */
2474 }
2475
2476 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
2477 {
2478         struct pppol2tp_tunnel *tunnel = v;
2479
2480         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
2481                    tunnel->name,
2482                    (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N',
2483                    atomic_read(&tunnel->ref_count) - 1);
2484         seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n",
2485                    tunnel->debug,
2486                    (unsigned long long)tunnel->stats.tx_packets,
2487                    (unsigned long long)tunnel->stats.tx_bytes,
2488                    (unsigned long long)tunnel->stats.tx_errors,
2489                    (unsigned long long)tunnel->stats.rx_packets,
2490                    (unsigned long long)tunnel->stats.rx_bytes,
2491                    (unsigned long long)tunnel->stats.rx_errors);
2492 }
2493
2494 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
2495 {
2496         struct pppol2tp_session *session = v;
2497
2498         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
2499                    "%04X/%04X %d %c\n",
2500                    session->name,
2501                    ntohl(session->tunnel_addr.addr.sin_addr.s_addr),
2502                    ntohs(session->tunnel_addr.addr.sin_port),
2503                    session->tunnel_addr.s_tunnel,
2504                    session->tunnel_addr.s_session,
2505                    session->tunnel_addr.d_tunnel,
2506                    session->tunnel_addr.d_session,
2507                    session->sock->sk_state,
2508                    (session == session->sock->sk_user_data) ?
2509                    'Y' : 'N');
2510         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
2511                    session->mtu, session->mru,
2512                    session->recv_seq ? 'R' : '-',
2513                    session->send_seq ? 'S' : '-',
2514                    session->lns_mode ? "LNS" : "LAC",
2515                    session->debug,
2516                    jiffies_to_msecs(session->reorder_timeout));
2517         seq_printf(m, "   %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n",
2518                    session->nr, session->ns,
2519                    (unsigned long long)session->stats.tx_packets,
2520                    (unsigned long long)session->stats.tx_bytes,
2521                    (unsigned long long)session->stats.tx_errors,
2522                    (unsigned long long)session->stats.rx_packets,
2523                    (unsigned long long)session->stats.rx_bytes,
2524                    (unsigned long long)session->stats.rx_errors);
2525 }
2526
2527 static int pppol2tp_seq_show(struct seq_file *m, void *v)
2528 {
2529         struct pppol2tp_seq_data *pd = v;
2530
2531         /* display header on line 1 */
2532         if (v == SEQ_START_TOKEN) {
2533                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
2534                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
2535                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2536                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
2537                          "dest-tid/sid state user-data-ok\n");
2538                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
2539                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2540                 goto out;
2541         }
2542
2543         /* Show the tunnel or session context.
2544          */
2545         if (pd->session == NULL)
2546                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
2547         else
2548                 pppol2tp_seq_session_show(m, pd->session);
2549
2550 out:
2551         return 0;
2552 }
2553
2554 static const struct seq_operations pppol2tp_seq_ops = {
2555         .start          = pppol2tp_seq_start,
2556         .next           = pppol2tp_seq_next,
2557         .stop           = pppol2tp_seq_stop,
2558         .show           = pppol2tp_seq_show,
2559 };
2560
2561 /* Called when our /proc file is opened. We allocate data for use when
2562  * iterating our tunnel / session contexts and store it in the private
2563  * data of the seq_file.
2564  */
2565 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
2566 {
2567         return seq_open_net(inode, file, &pppol2tp_seq_ops,
2568                             sizeof(struct pppol2tp_seq_data));
2569 }
2570
2571 static const struct file_operations pppol2tp_proc_fops = {
2572         .owner          = THIS_MODULE,
2573         .open           = pppol2tp_proc_open,
2574         .read           = seq_read,
2575         .llseek         = seq_lseek,
2576         .release        = seq_release_net,
2577 };
2578
2579 #endif /* CONFIG_PROC_FS */
2580
2581 /*****************************************************************************
2582  * Init and cleanup
2583  *****************************************************************************/
2584
2585 static const struct proto_ops pppol2tp_ops = {
2586         .family         = AF_PPPOX,
2587         .owner          = THIS_MODULE,
2588         .release        = pppol2tp_release,
2589         .bind           = sock_no_bind,
2590         .connect        = pppol2tp_connect,
2591         .socketpair     = sock_no_socketpair,
2592         .accept         = sock_no_accept,
2593         .getname        = pppol2tp_getname,
2594         .poll           = datagram_poll,
2595         .listen         = sock_no_listen,
2596         .shutdown       = sock_no_shutdown,
2597         .setsockopt     = pppol2tp_setsockopt,
2598         .getsockopt     = pppol2tp_getsockopt,
2599         .sendmsg        = pppol2tp_sendmsg,
2600         .recvmsg        = pppol2tp_recvmsg,
2601         .mmap           = sock_no_mmap,
2602         .ioctl          = pppox_ioctl,
2603 };
2604
2605 static struct pppox_proto pppol2tp_proto = {
2606         .create         = pppol2tp_create,
2607         .ioctl          = pppol2tp_ioctl
2608 };
2609
2610 static __net_init int pppol2tp_init_net(struct net *net)
2611 {
2612         struct pppol2tp_net *pn = pppol2tp_pernet(net);
2613         struct proc_dir_entry *pde;
2614
2615         INIT_LIST_HEAD(&pn->pppol2tp_tunnel_list);
2616         rwlock_init(&pn->pppol2tp_tunnel_list_lock);
2617
2618         pde = proc_net_fops_create(net, "pppol2tp", S_IRUGO, &pppol2tp_proc_fops);
2619 #ifdef CONFIG_PROC_FS
2620         if (!pde)
2621                 return -ENOMEM;
2622 #endif
2623
2624         return 0;
2625 }
2626
2627 static __net_exit void pppol2tp_exit_net(struct net *net)
2628 {
2629         proc_net_remove(net, "pppol2tp");
2630 }
2631
2632 static struct pernet_operations pppol2tp_net_ops = {
2633         .init = pppol2tp_init_net,
2634         .exit = pppol2tp_exit_net,
2635         .id   = &pppol2tp_net_id,
2636         .size = sizeof(struct pppol2tp_net),
2637 };
2638
2639 static int __init pppol2tp_init(void)
2640 {
2641         int err;
2642
2643         err = proto_register(&pppol2tp_sk_proto, 0);
2644         if (err)
2645                 goto out;
2646         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
2647         if (err)
2648                 goto out_unregister_pppol2tp_proto;
2649
2650         err = register_pernet_device(&pppol2tp_net_ops);
2651         if (err)
2652                 goto out_unregister_pppox_proto;
2653
2654         printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
2655                PPPOL2TP_DRV_VERSION);
2656
2657 out:
2658         return err;
2659 out_unregister_pppox_proto:
2660         unregister_pppox_proto(PX_PROTO_OL2TP);
2661 out_unregister_pppol2tp_proto:
2662         proto_unregister(&pppol2tp_sk_proto);
2663         goto out;
2664 }
2665
2666 static void __exit pppol2tp_exit(void)
2667 {
2668         unregister_pppox_proto(PX_PROTO_OL2TP);
2669         unregister_pernet_device(&pppol2tp_net_ops);
2670         proto_unregister(&pppol2tp_sk_proto);
2671 }
2672
2673 module_init(pppol2tp_init);
2674 module_exit(pppol2tp_exit);
2675
2676 MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, "
2677               "James Chapman <jchapman@katalix.com>");
2678 MODULE_DESCRIPTION("PPP over L2TP over UDP");
2679 MODULE_LICENSE("GPL");
2680 MODULE_VERSION(PPPOL2TP_DRV_VERSION);