drivers/net/pppol2tp.c

   1 /*****************************************************************************
   2  * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
   3  *
   4  * PPPoX    --- Generic PPP encapsulation socket family
   5  * PPPoL2TP --- PPP over L2TP (RFC 2661)
   6  *
   7  * Version:     1.0.0
   8  *
   9  * Authors:     Martijn van Oosterhout <kleptog@svana.org>
  10  *              James Chapman (jchapman@katalix.com)
  11  * Contributors:
  12  *              Michal Ostrowski <mostrows@speakeasy.net>
  13  *              Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
  14  *              David S. Miller (davem@redhat.com)
  15  *
  16  * License:
  17  *              This program is free software; you can redistribute it and/or
  18  *              modify it under the terms of the GNU General Public License
  19  *              as published by the Free Software Foundation; either version
  20  *              2 of the License, or (at your option) any later version.
  21  *
  22  */
  23
  24 /* This driver handles only L2TP data frames; control frames are handled by a
  25  * userspace application.
  26  *
  27  * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
  28  * attaches it to a bound UDP socket with local tunnel_id / session_id and
  29  * peer tunnel_id / session_id set. Data can then be sent or received using
  30  * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
  31  * can be read or modified using ioctl() or [gs]etsockopt() calls.
  32  *
  33  * When a PPPoL2TP socket is connected with local and peer session_id values
  34  * zero, the socket is treated as a special tunnel management socket.
  35  *
  36  * Here's example userspace code to create a socket for sending/receiving data
  37  * over an L2TP session:-
  38  *
  39  *      struct sockaddr_pppol2tp sax;
  40  *      int fd;
  41  *      int session_fd;
  42  *
  43  *      fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
  44  *
  45  *      sax.sa_family = AF_PPPOX;
  46  *      sax.sa_protocol = PX_PROTO_OL2TP;
  47  *      sax.pppol2tp.fd = tunnel_fd;    // bound UDP socket
  48  *      sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
  49  *      sax.pppol2tp.addr.sin_port = addr->sin_port;
  50  *      sax.pppol2tp.addr.sin_family = AF_INET;
  51  *      sax.pppol2tp.s_tunnel  = tunnel_id;
  52  *      sax.pppol2tp.s_session = session_id;
  53  *      sax.pppol2tp.d_tunnel  = peer_tunnel_id;
  54  *      sax.pppol2tp.d_session = peer_session_id;
  55  *
  56  *      session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
  57  *
  58  * A pppd plugin that allows PPP traffic to be carried over L2TP using
  59  * this driver is available from the OpenL2TP project at
  60  * http://openl2tp.sourceforge.net.
  61  */
  62
  63 #include <linux/module.h>
  64 #include <linux/string.h>
  65 #include <linux/list.h>
  66 #include <asm/uaccess.h>
  67
  68 #include <linux/kernel.h>
  69 #include <linux/spinlock.h>
  70 #include <linux/kthread.h>
  71 #include <linux/sched.h>
  72 #include <linux/slab.h>
  73 #include <linux/errno.h>
  74 #include <linux/jiffies.h>
  75
  76 #include <linux/netdevice.h>
  77 #include <linux/net.h>
  78 #include <linux/inetdevice.h>
  79 #include <linux/skbuff.h>
  80 #include <linux/init.h>
  81 #include <linux/ip.h>
  82 #include <linux/udp.h>
  83 #include <linux/if_pppox.h>
  84 #include <linux/if_pppol2tp.h>
  85 #include <net/sock.h>
  86 #include <linux/ppp_channel.h>
  87 #include <linux/ppp_defs.h>
  88 #include <linux/if_ppp.h>
  89 #include <linux/file.h>
  90 #include <linux/hash.h>
  91 #include <linux/sort.h>
  92 #include <linux/proc_fs.h>
  93 #include <linux/nsproxy.h>
  94 #include <net/net_namespace.h>
  95 #include <net/netns/generic.h>
  96 #include <net/dst.h>
  97 #include <net/ip.h>
  98 #include <net/udp.h>
  99 #include <net/xfrm.h>
 100
 101 #include <asm/byteorder.h>
 102 #include <asm/atomic.h>
 103
 104
 105 #define PPPOL2TP_DRV_VERSION    "V1.0"
 106
 107 /* L2TP header constants */
 108 #define L2TP_HDRFLAG_T     0x8000
 109 #define L2TP_HDRFLAG_L     0x4000
 110 #define L2TP_HDRFLAG_S     0x0800
 111 #define L2TP_HDRFLAG_O     0x0200
 112 #define L2TP_HDRFLAG_P     0x0100
 113
 114 #define L2TP_HDR_VER_MASK  0x000F
 115 #define L2TP_HDR_VER       0x0002
 116
 117 /* Space for UDP, L2TP and PPP headers */
 118 #define PPPOL2TP_HEADER_OVERHEAD        40
 119
 120 /* Just some random numbers */
 121 #define L2TP_TUNNEL_MAGIC       0x42114DDA
 122 #define L2TP_SESSION_MAGIC      0x0C04EB7D
 123
 124 #define PPPOL2TP_HASH_BITS      4
 125 #define PPPOL2TP_HASH_SIZE      (1 << PPPOL2TP_HASH_BITS)
 126
 127 /* Default trace flags */
 128 #define PPPOL2TP_DEFAULT_DEBUG_FLAGS    0
 129
 130 #define PRINTK(_mask, _type, _lvl, _fmt, args...)                       \
 131         do {                                                            \
 132                 if ((_mask) & (_type))                                  \
 133                         printk(_lvl "PPPOL2TP: " _fmt, ##args);         \
 134         } while(0)
 135
 136 /* Number of bytes to build transmit L2TP headers.
 137  * Unfortunately the size is different depending on whether sequence numbers
 138  * are enabled.
 139  */
 140 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ              10
 141 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ            6
 142
 143 struct pppol2tp_tunnel;
 144
 145 /* Describes a session. It is the sk_user_data field in the PPPoL2TP
 146  * socket. Contains information to determine incoming packets and transmit
 147  * outgoing ones.
 148  */
 149 struct pppol2tp_session
 150 {
 151         int                     magic;          /* should be
 152                                                  * L2TP_SESSION_MAGIC */
 153         int                     owner;          /* pid that opened the socket */
 154
 155         struct sock             *sock;          /* Pointer to the session
 156                                                  * PPPoX socket */
 157         struct sock             *tunnel_sock;   /* Pointer to the tunnel UDP
 158                                                  * socket */
 159
 160         struct pppol2tp_addr    tunnel_addr;    /* Description of tunnel */
 161
 162         struct pppol2tp_tunnel  *tunnel;        /* back pointer to tunnel
 163                                                  * context */
 164
 165         char                    name[20];       /* "sess xxxxx/yyyyy", where
 166                                                  * x=tunnel_id, y=session_id */
 167         int                     mtu;
 168         int                     mru;
 169         int                     flags;          /* accessed by PPPIOCGFLAGS.
 170                                                  * Unused. */
 171         unsigned                recv_seq:1;     /* expect receive packets with
 172                                                  * sequence numbers? */
 173         unsigned                send_seq:1;     /* send packets with sequence
 174                                                  * numbers? */
 175         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
 176                                                  * sequence numbers under
 177                                                  * control of LNS. */
 178         int                     debug;          /* bitmask of debug message
 179                                                  * categories */
 180         int                     reorder_timeout; /* configured reorder timeout
 181                                                   * (in jiffies) */
 182         u16                     nr;             /* session NR state (receive) */
 183         u16                     ns;             /* session NR state (send) */
 184         struct sk_buff_head     reorder_q;      /* receive reorder queue */
 185         struct pppol2tp_ioc_stats stats;
 186         struct hlist_node       hlist;          /* Hash list node */
 187 };
 188
 189 /* The sk_user_data field of the tunnel's UDP socket. It contains info to track
 190  * all the associated sessions so incoming packets can be sorted out
 191  */
 192 struct pppol2tp_tunnel
 193 {
 194         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 195         rwlock_t                hlist_lock;     /* protect session_hlist */
 196         struct hlist_head       session_hlist[PPPOL2TP_HASH_SIZE];
 197                                                 /* hashed list of sessions,
 198                                                  * hashed by id */
 199         int                     debug;          /* bitmask of debug message
 200                                                  * categories */
 201         char                    name[12];       /* "tunl xxxxx" */
 202         struct pppol2tp_ioc_stats stats;
 203
 204         void (*old_sk_destruct)(struct sock *);
 205
 206         struct sock             *sock;          /* Parent socket */
 207         struct list_head        list;           /* Keep a list of all open
 208                                                  * prepared sockets */
 209         struct net              *pppol2tp_net;  /* the net we belong to */
 210
 211         atomic_t                ref_count;
 212 };
 213
 214 /* Private data stored for received packets in the skb.
 215  */
 216 struct pppol2tp_skb_cb {
 217         u16                     ns;
 218         u16                     nr;
 219         u16                     has_seq;
 220         u16                     length;
 221         unsigned long           expires;
 222 };
 223
 224 #define PPPOL2TP_SKB_CB(skb)    ((struct pppol2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
 225
 226 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
 227 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel);
 228
 229 static atomic_t pppol2tp_tunnel_count;
 230 static atomic_t pppol2tp_session_count;
 231 static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
 232 static struct proto_ops pppol2tp_ops;
 233
 234 /* per-net private data for this module */
 235 static int pppol2tp_net_id;
 236 struct pppol2tp_net {
 237         struct list_head pppol2tp_tunnel_list;
 238         rwlock_t pppol2tp_tunnel_list_lock;
 239 };
 240
 241 static inline struct pppol2tp_net *pppol2tp_pernet(struct net *net)
 242 {
 243         BUG_ON(!net);
 244
 245         return net_generic(net, pppol2tp_net_id);
 246 }
 247
 248 /* Helpers to obtain tunnel/session contexts from sockets.
 249  */
 250 static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk)
 251 {
 252         struct pppol2tp_session *session;
 253
 254         if (sk == NULL)
 255                 return NULL;
 256
 257         sock_hold(sk);
 258         session = (struct pppol2tp_session *)(sk->sk_user_data);
 259         if (session == NULL) {
 260                 sock_put(sk);
 261                 goto out;
 262         }
 263
 264         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 265 out:
 266         return session;
 267 }
 268
 269 static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk)
 270 {
 271         struct pppol2tp_tunnel *tunnel;
 272
 273         if (sk == NULL)
 274                 return NULL;
 275
 276         sock_hold(sk);
 277         tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data);
 278         if (tunnel == NULL) {
 279                 sock_put(sk);
 280                 goto out;
 281         }
 282
 283         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 284 out:
 285         return tunnel;
 286 }
 287
 288 /* Tunnel reference counts. Incremented per session that is added to
 289  * the tunnel.
 290  */
 291 static inline void pppol2tp_tunnel_inc_refcount(struct pppol2tp_tunnel *tunnel)
 292 {
 293         atomic_inc(&tunnel->ref_count);
 294 }
 295
 296 static inline void pppol2tp_tunnel_dec_refcount(struct pppol2tp_tunnel *tunnel)
 297 {
 298         if (atomic_dec_and_test(&tunnel->ref_count))
 299                 pppol2tp_tunnel_free(tunnel);
 300 }
 301
 302 /* Session hash list.
 303  * The session_id SHOULD be random according to RFC2661, but several
 304  * L2TP implementations (Cisco and Microsoft) use incrementing
 305  * session_ids.  So we do a real hash on the session_id, rather than a
 306  * simple bitmask.
 307  */
 308 static inline struct hlist_head *
 309 pppol2tp_session_id_hash(struct pppol2tp_tunnel *tunnel, u16 session_id)
 310 {
 311         unsigned long hash_val = (unsigned long) session_id;
 312         return &tunnel->session_hlist[hash_long(hash_val, PPPOL2TP_HASH_BITS)];
 313 }
 314
 315 /* Lookup a session by id
 316  */
 317 static struct pppol2tp_session *
 318 pppol2tp_session_find(struct pppol2tp_tunnel *tunnel, u16 session_id)
 319 {
 320         struct hlist_head *session_list =
 321                 pppol2tp_session_id_hash(tunnel, session_id);
 322         struct pppol2tp_session *session;
 323         struct hlist_node *walk;
 324
 325         read_lock_bh(&tunnel->hlist_lock);
 326         hlist_for_each_entry(session, walk, session_list, hlist) {
 327                 if (session->tunnel_addr.s_session == session_id) {
 328                         read_unlock_bh(&tunnel->hlist_lock);
 329                         return session;
 330                 }
 331         }
 332         read_unlock_bh(&tunnel->hlist_lock);
 333
 334         return NULL;
 335 }
 336
 337 /* Lookup a tunnel by id
 338  */
 339 static struct pppol2tp_tunnel *pppol2tp_tunnel_find(struct net *net, u16 tunnel_id)
 340 {
 341         struct pppol2tp_tunnel *tunnel;
 342         struct pppol2tp_net *pn = pppol2tp_pernet(net);
 343
 344         read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
 345         list_for_each_entry(tunnel, &pn->pppol2tp_tunnel_list, list) {
 346                 if (tunnel->stats.tunnel_id == tunnel_id) {
 347                         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
 348                         return tunnel;
 349                 }
 350         }
 351         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
 352
 353         return NULL;
 354 }
 355
 356 /*****************************************************************************
 357  * Receive data handling
 358  *****************************************************************************/
 359
 360 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
 361  * number.
 362  */
 363 static void pppol2tp_recv_queue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 364 {
 365         struct sk_buff *skbp;
 366         struct sk_buff *tmp;
 367         u16 ns = PPPOL2TP_SKB_CB(skb)->ns;
 368
 369         spin_lock_bh(&session->reorder_q.lock);
 370         skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
 371                 if (PPPOL2TP_SKB_CB(skbp)->ns > ns) {
 372                         __skb_queue_before(&session->reorder_q, skbp, skb);
 373                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 374                                "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
 375                                session->name, ns, PPPOL2TP_SKB_CB(skbp)->ns,
 376                                skb_queue_len(&session->reorder_q));
 377                         session->stats.rx_oos_packets++;
 378                         goto out;
 379                 }
 380         }
 381
 382         __skb_queue_tail(&session->reorder_q, skb);
 383
 384 out:
 385         spin_unlock_bh(&session->reorder_q.lock);
 386 }
 387
 388 /* Dequeue a single skb.
 389  */
 390 static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 391 {
 392         struct pppol2tp_tunnel *tunnel = session->tunnel;
 393         int length = PPPOL2TP_SKB_CB(skb)->length;
 394         struct sock *session_sock = NULL;
 395
 396         /* We're about to requeue the skb, so return resources
 397          * to its current owner (a socket receive buffer).
 398          */
 399         skb_orphan(skb);
 400
 401         tunnel->stats.rx_packets++;
 402         tunnel->stats.rx_bytes += length;
 403         session->stats.rx_packets++;
 404         session->stats.rx_bytes += length;
 405
 406         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 407                 /* Bump our Nr */
 408                 session->nr++;
 409                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 410                        "%s: updated nr to %hu\n", session->name, session->nr);
 411         }
 412
 413         /* If the socket is bound, send it in to PPP's input queue. Otherwise
 414          * queue it on the session socket.
 415          */
 416         session_sock = session->sock;
 417         if (session_sock->sk_state & PPPOX_BOUND) {
 418                 struct pppox_sock *po;
 419                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 420                        "%s: recv %d byte data frame, passing to ppp\n",
 421                        session->name, length);
 422
 423                 /* We need to forget all info related to the L2TP packet
 424                  * gathered in the skb as we are going to reuse the same
 425                  * skb for the inner packet.
 426                  * Namely we need to:
 427                  * - reset xfrm (IPSec) information as it applies to
 428                  *   the outer L2TP packet and not to the inner one
 429                  * - release the dst to force a route lookup on the inner
 430                  *   IP packet since skb->dst currently points to the dst
 431                  *   of the UDP tunnel
 432                  * - reset netfilter information as it doesn't apply
 433                  *   to the inner packet either
 434                  */
 435                 secpath_reset(skb);
 436                 dst_release(skb->dst);
 437                 skb->dst = NULL;
 438                 nf_reset(skb);
 439
 440                 po = pppox_sk(session_sock);
 441                 ppp_input(&po->chan, skb);
 442         } else {
 443                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 444                        "%s: socket not bound\n", session->name);
 445
 446                 /* Not bound. Nothing we can do, so discard. */
 447                 session->stats.rx_errors++;
 448                 kfree_skb(skb);
 449         }
 450
 451         sock_put(session->sock);
 452 }
 453
 454 /* Dequeue skbs from the session's reorder_q, subject to packet order.
 455  * Skbs that have been in the queue for too long are simply discarded.
 456  */
 457 static void pppol2tp_recv_dequeue(struct pppol2tp_session *session)
 458 {
 459         struct sk_buff *skb;
 460         struct sk_buff *tmp;
 461
 462         /* If the pkt at the head of the queue has the nr that we
 463          * expect to send up next, dequeue it and any other
 464          * in-sequence packets behind it.
 465          */
 466         spin_lock_bh(&session->reorder_q.lock);
 467         skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
 468                 if (time_after(jiffies, PPPOL2TP_SKB_CB(skb)->expires)) {
 469                         session->stats.rx_seq_discards++;
 470                         session->stats.rx_errors++;
 471                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 472                                "%s: oos pkt %hu len %d discarded (too old), "
 473                                "waiting for %hu, reorder_q_len=%d\n",
 474                                session->name, PPPOL2TP_SKB_CB(skb)->ns,
 475                                PPPOL2TP_SKB_CB(skb)->length, session->nr,
 476                                skb_queue_len(&session->reorder_q));
 477                         __skb_unlink(skb, &session->reorder_q);
 478                         kfree_skb(skb);
 479                         sock_put(session->sock);
 480                         continue;
 481                 }
 482
 483                 if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 484                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 485                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 486                                        "%s: holding oos pkt %hu len %d, "
 487                                        "waiting for %hu, reorder_q_len=%d\n",
 488                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 489                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 490                                        skb_queue_len(&session->reorder_q));
 491                                 goto out;
 492                         }
 493                 }
 494                 __skb_unlink(skb, &session->reorder_q);
 495
 496                 /* Process the skb. We release the queue lock while we
 497                  * do so to let other contexts process the queue.
 498                  */
 499                 spin_unlock_bh(&session->reorder_q.lock);
 500                 pppol2tp_recv_dequeue_skb(session, skb);
 501                 spin_lock_bh(&session->reorder_q.lock);
 502         }
 503
 504 out:
 505         spin_unlock_bh(&session->reorder_q.lock);
 506 }
 507
 508 static inline int pppol2tp_verify_udp_checksum(struct sock *sk,
 509                                                struct sk_buff *skb)
 510 {
 511         struct udphdr *uh = udp_hdr(skb);
 512         u16 ulen = ntohs(uh->len);
 513         struct inet_sock *inet;
 514         __wsum psum;
 515
 516         if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
 517                 return 0;
 518
 519         inet = inet_sk(sk);
 520         psum = csum_tcpudp_nofold(inet->saddr, inet->daddr, ulen,
 521                                   IPPROTO_UDP, 0);
 522
 523         if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
 524             !csum_fold(csum_add(psum, skb->csum)))
 525                 return 0;
 526
 527         skb->csum = psum;
 528
 529         return __skb_checksum_complete(skb);
 530 }
 531
 532 /* Internal receive frame. Do the real work of receiving an L2TP data frame
 533  * here. The skb is not on a list when we get here.
 534  * Returns 0 if the packet was a data packet and was successfully passed on.
 535  * Returns 1 if the packet was not a good data packet and could not be
 536  * forwarded.  All such packets are passed up to userspace to deal with.
 537  */
 538 static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
 539 {
 540         struct pppol2tp_session *session = NULL;
 541         struct pppol2tp_tunnel *tunnel;
 542         unsigned char *ptr, *optr;
 543         u16 hdrflags;
 544         u16 tunnel_id, session_id;
 545         int length;
 546         int offset;
 547
 548         tunnel = pppol2tp_sock_to_tunnel(sock);
 549         if (tunnel == NULL)
 550                 goto no_tunnel;
 551
 552         if (tunnel->sock && pppol2tp_verify_udp_checksum(tunnel->sock, skb))
 553                 goto discard_bad_csum;
 554
 555         /* UDP always verifies the packet length. */
 556         __skb_pull(skb, sizeof(struct udphdr));
 557
 558         /* Short packet? */
 559         if (!pskb_may_pull(skb, 12)) {
 560                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 561                        "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
 562                 goto error;
 563         }
 564
 565         /* Point to L2TP header */
 566         optr = ptr = skb->data;
 567
 568         /* Get L2TP header flags */
 569         hdrflags = ntohs(*(__be16*)ptr);
 570
 571         /* Trace packet contents, if enabled */
 572         if (tunnel->debug & PPPOL2TP_MSG_DATA) {
 573                 length = min(16u, skb->len);
 574                 if (!pskb_may_pull(skb, length))
 575                         goto error;
 576
 577                 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
 578
 579                 offset = 0;
 580                 do {
 581                         printk(" %02X", ptr[offset]);
 582                 } while (++offset < length);
 583
 584                 printk("\n");
 585         }
 586
 587         /* Get length of L2TP packet */
 588         length = skb->len;
 589
 590         /* If type is control packet, it is handled by userspace. */
 591         if (hdrflags & L2TP_HDRFLAG_T) {
 592                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 593                        "%s: recv control packet, len=%d\n", tunnel->name, length);
 594                 goto error;
 595         }
 596
 597         /* Skip flags */
 598         ptr += 2;
 599
 600         /* If length is present, skip it */
 601         if (hdrflags & L2TP_HDRFLAG_L)
 602                 ptr += 2;
 603
 604         /* Extract tunnel and session ID */
 605         tunnel_id = ntohs(*(__be16 *) ptr);
 606         ptr += 2;
 607         session_id = ntohs(*(__be16 *) ptr);
 608         ptr += 2;
 609
 610         /* Find the session context */
 611         session = pppol2tp_session_find(tunnel, session_id);
 612         if (!session) {
 613                 /* Not found? Pass to userspace to deal with */
 614                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 615                        "%s: no socket found (%hu/%hu). Passing up.\n",
 616                        tunnel->name, tunnel_id, session_id);
 617                 goto error;
 618         }
 619         sock_hold(session->sock);
 620
 621         /* The ref count on the socket was increased by the above call since
 622          * we now hold a pointer to the session. Take care to do sock_put()
 623          * when exiting this function from now on...
 624          */
 625
 626         /* Handle the optional sequence numbers.  If we are the LAC,
 627          * enable/disable sequence numbers under the control of the LNS.  If
 628          * no sequence numbers present but we were expecting them, discard
 629          * frame.
 630          */
 631         if (hdrflags & L2TP_HDRFLAG_S) {
 632                 u16 ns, nr;
 633                 ns = ntohs(*(__be16 *) ptr);
 634                 ptr += 2;
 635                 nr = ntohs(*(__be16 *) ptr);
 636                 ptr += 2;
 637
 638                 /* Received a packet with sequence numbers. If we're the LNS,
 639                  * check if we sre sending sequence numbers and if not,
 640                  * configure it so.
 641                  */
 642                 if ((!session->lns_mode) && (!session->send_seq)) {
 643                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 644                                "%s: requested to enable seq numbers by LNS\n",
 645                                session->name);
 646                         session->send_seq = -1;
 647                 }
 648
 649                 /* Store L2TP info in the skb */
 650                 PPPOL2TP_SKB_CB(skb)->ns = ns;
 651                 PPPOL2TP_SKB_CB(skb)->nr = nr;
 652                 PPPOL2TP_SKB_CB(skb)->has_seq = 1;
 653
 654                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 655                        "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n",
 656                        session->name, ns, nr, session->nr);
 657         } else {
 658                 /* No sequence numbers.
 659                  * If user has configured mandatory sequence numbers, discard.
 660                  */
 661                 if (session->recv_seq) {
 662                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 663                                "%s: recv data has no seq numbers when required. "
 664                                "Discarding\n", session->name);
 665                         session->stats.rx_seq_discards++;
 666                         goto discard;
 667                 }
 668
 669                 /* If we're the LAC and we're sending sequence numbers, the
 670                  * LNS has requested that we no longer send sequence numbers.
 671                  * If we're the LNS and we're sending sequence numbers, the
 672                  * LAC is broken. Discard the frame.
 673                  */
 674                 if ((!session->lns_mode) && (session->send_seq)) {
 675                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 676                                "%s: requested to disable seq numbers by LNS\n",
 677                                session->name);
 678                         session->send_seq = 0;
 679                 } else if (session->send_seq) {
 680                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 681                                "%s: recv data has no seq numbers when required. "
 682                                "Discarding\n", session->name);
 683                         session->stats.rx_seq_discards++;
 684                         goto discard;
 685                 }
 686
 687                 /* Store L2TP info in the skb */
 688                 PPPOL2TP_SKB_CB(skb)->has_seq = 0;
 689         }
 690
 691         /* If offset bit set, skip it. */
 692         if (hdrflags & L2TP_HDRFLAG_O) {
 693                 offset = ntohs(*(__be16 *)ptr);
 694                 ptr += 2 + offset;
 695         }
 696
 697         offset = ptr - optr;
 698         if (!pskb_may_pull(skb, offset))
 699                 goto discard;
 700
 701         __skb_pull(skb, offset);
 702
 703         /* Skip PPP header, if present.  In testing, Microsoft L2TP clients
 704          * don't send the PPP header (PPP header compression enabled), but
 705          * other clients can include the header. So we cope with both cases
 706          * here. The PPP header is always FF03 when using L2TP.
 707          *
 708          * Note that skb->data[] isn't dereferenced from a u16 ptr here since
 709          * the field may be unaligned.
 710          */
 711         if (!pskb_may_pull(skb, 2))
 712                 goto discard;
 713
 714         if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
 715                 skb_pull(skb, 2);
 716
 717         /* Prepare skb for adding to the session's reorder_q.  Hold
 718          * packets for max reorder_timeout or 1 second if not
 719          * reordering.
 720          */
 721         PPPOL2TP_SKB_CB(skb)->length = length;
 722         PPPOL2TP_SKB_CB(skb)->expires = jiffies +
 723                 (session->reorder_timeout ? session->reorder_timeout : HZ);
 724
 725         /* Add packet to the session's receive queue. Reordering is done here, if
 726          * enabled. Saved L2TP protocol info is stored in skb->sb[].
 727          */
 728         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 729                 if (session->reorder_timeout != 0) {
 730                         /* Packet reordering enabled. Add skb to session's
 731                          * reorder queue, in order of ns.
 732                          */
 733                         pppol2tp_recv_queue_skb(session, skb);
 734                 } else {
 735                         /* Packet reordering disabled. Discard out-of-sequence
 736                          * packets
 737                          */
 738                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 739                                 session->stats.rx_seq_discards++;
 740                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 741                                        "%s: oos pkt %hu len %d discarded, "
 742                                        "waiting for %hu, reorder_q_len=%d\n",
 743                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 744                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 745                                        skb_queue_len(&session->reorder_q));
 746                                 goto discard;
 747                         }
 748                         skb_queue_tail(&session->reorder_q, skb);
 749                 }
 750         } else {
 751                 /* No sequence numbers. Add the skb to the tail of the
 752                  * reorder queue. This ensures that it will be
 753                  * delivered after all previous sequenced skbs.
 754                  */
 755                 skb_queue_tail(&session->reorder_q, skb);
 756         }
 757
 758         /* Try to dequeue as many skbs from reorder_q as we can. */
 759         pppol2tp_recv_dequeue(session);
 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
 777         return 0;
 778
 779 error:
 780         /* Put UDP header back */
 781         __skb_push(skb, sizeof(struct udphdr));
 782         sock_put(sock);
 783
 784 no_tunnel:
 785         return 1;
 786 }
 787
 788 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
 789  * Return codes:
 790  * 0 : success.
 791  * <0: error
 792  * >0: skb should be passed up to userspace as UDP.
 793  */
 794 static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 795 {
 796         struct pppol2tp_tunnel *tunnel;
 797
 798         tunnel = pppol2tp_sock_to_tunnel(sk);
 799         if (tunnel == NULL)
 800                 goto pass_up;
 801
 802         PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 803                "%s: received %d bytes\n", tunnel->name, skb->len);
 804
 805         if (pppol2tp_recv_core(sk, skb))
 806                 goto pass_up_put;
 807
 808         sock_put(sk);
 809         return 0;
 810
 811 pass_up_put:
 812         sock_put(sk);
 813 pass_up:
 814         return 1;
 815 }
 816
 817 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
 818  */
 819 static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
 820                             struct msghdr *msg, size_t len,
 821                             int flags)
 822 {
 823         int err;
 824         struct sk_buff *skb;
 825         struct sock *sk = sock->sk;
 826
 827         err = -EIO;
 828         if (sk->sk_state & PPPOX_BOUND)
 829                 goto end;
 830
 831         msg->msg_namelen = 0;
 832
 833         err = 0;
 834         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 835                                 flags & MSG_DONTWAIT, &err);
 836         if (!skb)
 837                 goto end;
 838
 839         if (len > skb->len)
 840                 len = skb->len;
 841         else if (len < skb->len)
 842                 msg->msg_flags |= MSG_TRUNC;
 843
 844         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
 845         if (likely(err == 0))
 846                 err = len;
 847
 848         kfree_skb(skb);
 849 end:
 850         return err;
 851 }
 852
 853 /************************************************************************
 854  * Transmit handling
 855  ***********************************************************************/
 856
 857 /* Tell how big L2TP headers are for a particular session. This
 858  * depends on whether sequence numbers are being used.
 859  */
 860 static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session)
 861 {
 862         if (session->send_seq)
 863                 return PPPOL2TP_L2TP_HDR_SIZE_SEQ;
 864
 865         return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
 866 }
 867
 868 /* Build an L2TP header for the session into the buffer provided.
 869  */
 870 static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session,
 871                                        void *buf)
 872 {
 873         __be16 *bufp = buf;
 874         u16 flags = L2TP_HDR_VER;
 875
 876         if (session->send_seq)
 877                 flags |= L2TP_HDRFLAG_S;
 878
 879         /* Setup L2TP header.
 880          * FIXME: Can this ever be unaligned? Is direct dereferencing of
 881          * 16-bit header fields safe here for all architectures?
 882          */
 883         *bufp++ = htons(flags);
 884         *bufp++ = htons(session->tunnel_addr.d_tunnel);
 885         *bufp++ = htons(session->tunnel_addr.d_session);
 886         if (session->send_seq) {
 887                 *bufp++ = htons(session->ns);
 888                 *bufp++ = 0;
 889                 session->ns++;
 890                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 891                        "%s: updated ns to %hu\n", session->name, session->ns);
 892         }
 893 }
 894
 895 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
 896  * when a user application does a sendmsg() on the session socket. L2TP and
 897  * PPP headers must be inserted into the user's data.
 898  */
 899 static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
 900                             size_t total_len)
 901 {
 902         static const unsigned char ppph[2] = { 0xff, 0x03 };
 903         struct sock *sk = sock->sk;
 904         struct inet_sock *inet;
 905         __wsum csum;
 906         struct sk_buff *skb;
 907         int error;
 908         int hdr_len;
 909         struct pppol2tp_session *session;
 910         struct pppol2tp_tunnel *tunnel;
 911         struct udphdr *uh;
 912         unsigned int len;
 913         struct sock *sk_tun;
 914         u16 udp_len;
 915
 916         error = -ENOTCONN;
 917         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 918                 goto error;
 919
 920         /* Get session and tunnel contexts */
 921         error = -EBADF;
 922         session = pppol2tp_sock_to_session(sk);
 923         if (session == NULL)
 924                 goto error;
 925
 926         sk_tun = session->tunnel_sock;
 927         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
 928         if (tunnel == NULL)
 929                 goto error_put_sess;
 930
 931         /* What header length is configured for this session? */
 932         hdr_len = pppol2tp_l2tp_header_len(session);
 933
 934         /* Allocate a socket buffer */
 935         error = -ENOMEM;
 936         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
 937                            sizeof(struct udphdr) + hdr_len +
 938                            sizeof(ppph) + total_len,
 939                            0, GFP_KERNEL);
 940         if (!skb)
 941                 goto error_put_sess_tun;
 942
 943         /* Reserve space for headers. */
 944         skb_reserve(skb, NET_SKB_PAD);
 945         skb_reset_network_header(skb);
 946         skb_reserve(skb, sizeof(struct iphdr));
 947         skb_reset_transport_header(skb);
 948
 949         /* Build UDP header */
 950         inet = inet_sk(sk_tun);
 951         udp_len = hdr_len + sizeof(ppph) + total_len;
 952         uh = (struct udphdr *) skb->data;
 953         uh->source = inet->sport;
 954         uh->dest = inet->dport;
 955         uh->len = htons(udp_len);
 956         uh->check = 0;
 957         skb_put(skb, sizeof(struct udphdr));
 958
 959         /* Build L2TP header */
 960         pppol2tp_build_l2tp_header(session, skb->data);
 961         skb_put(skb, hdr_len);
 962
 963         /* Add PPP header */
 964         skb->data[0] = ppph[0];
 965         skb->data[1] = ppph[1];
 966         skb_put(skb, 2);
 967
 968         /* Copy user data into skb */
 969         error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
 970         if (error < 0) {
 971                 kfree_skb(skb);
 972                 goto error_put_sess_tun;
 973         }
 974         skb_put(skb, total_len);
 975
 976         /* Calculate UDP checksum if configured to do so */
 977         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
 978                 skb->ip_summed = CHECKSUM_NONE;
 979         else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
 980                 skb->ip_summed = CHECKSUM_COMPLETE;
 981                 csum = skb_checksum(skb, 0, udp_len, 0);
 982                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
 983                                               udp_len, IPPROTO_UDP, csum);
 984                 if (uh->check == 0)
 985                         uh->check = CSUM_MANGLED_0;
 986         } else {
 987                 skb->ip_summed = CHECKSUM_PARTIAL;
 988                 skb->csum_start = skb_transport_header(skb) - skb->head;
 989                 skb->csum_offset = offsetof(struct udphdr, check);
 990                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
 991                                                udp_len, IPPROTO_UDP, 0);
 992         }
 993
 994         /* Debug */
 995         if (session->send_seq)
 996                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 997                        "%s: send %Zd bytes, ns=%hu\n", session->name,
 998                        total_len, session->ns - 1);
 999         else
1000                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1001                        "%s: send %Zd bytes\n", session->name, total_len);
1002
1003         if (session->debug & PPPOL2TP_MSG_DATA) {
1004                 int i;
1005                 unsigned char *datap = skb->data;
1006
1007                 printk(KERN_DEBUG "%s: xmit:", session->name);
1008                 for (i = 0; i < total_len; i++) {
1009                         printk(" %02X", *datap++);
1010                         if (i == 15) {
1011                                 printk(" ...");
1012                                 break;
1013                         }
1014                 }
1015                 printk("\n");
1016         }
1017
1018         /* Queue the packet to IP for output */
1019         len = skb->len;
1020         error = ip_queue_xmit(skb, 1);
1021
1022         /* Update stats */
1023         if (error >= 0) {
1024                 tunnel->stats.tx_packets++;
1025                 tunnel->stats.tx_bytes += len;
1026                 session->stats.tx_packets++;
1027                 session->stats.tx_bytes += len;
1028         } else {
1029                 tunnel->stats.tx_errors++;
1030                 session->stats.tx_errors++;
1031         }
1032
1033         return error;
1034
1035 error_put_sess_tun:
1036         sock_put(session->tunnel_sock);
1037 error_put_sess:
1038         sock_put(sk);
1039 error:
1040         return error;
1041 }
1042
1043 /* Automatically called when the skb is freed.
1044  */
1045 static void pppol2tp_sock_wfree(struct sk_buff *skb)
1046 {
1047         sock_put(skb->sk);
1048 }
1049
1050 /* For data skbs that we transmit, we associate with the tunnel socket
1051  * but don't do accounting.
1052  */
1053 static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1054 {
1055         sock_hold(sk);
1056         skb->sk = sk;
1057         skb->destructor = pppol2tp_sock_wfree;
1058 }
1059
1060 /* Transmit function called by generic PPP driver.  Sends PPP frame
1061  * over PPPoL2TP socket.
1062  *
1063  * This is almost the same as pppol2tp_sendmsg(), but rather than
1064  * being called with a msghdr from userspace, it is called with a skb
1065  * from the kernel.
1066  *
1067  * The supplied skb from ppp doesn't have enough headroom for the
1068  * insertion of L2TP, UDP and IP headers so we need to allocate more
1069  * headroom in the skb. This will create a cloned skb. But we must be
1070  * careful in the error case because the caller will expect to free
1071  * the skb it supplied, not our cloned skb. So we take care to always
1072  * leave the original skb unfreed if we return an error.
1073  */
1074 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
1075 {
1076         static const u8 ppph[2] = { 0xff, 0x03 };
1077         struct sock *sk = (struct sock *) chan->private;
1078         struct sock *sk_tun;
1079         int hdr_len;
1080         u16 udp_len;
1081         struct pppol2tp_session *session;
1082         struct pppol2tp_tunnel *tunnel;
1083         int rc;
1084         int headroom;
1085         int data_len = skb->len;
1086         struct inet_sock *inet;
1087         __wsum csum;
1088         struct udphdr *uh;
1089         unsigned int len;
1090         int old_headroom;
1091         int new_headroom;
1092
1093         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
1094                 goto abort;
1095
1096         /* Get session and tunnel contexts from the socket */
1097         session = pppol2tp_sock_to_session(sk);
1098         if (session == NULL)
1099                 goto abort;
1100
1101         sk_tun = session->tunnel_sock;
1102         if (sk_tun == NULL)
1103                 goto abort_put_sess;
1104         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
1105         if (tunnel == NULL)
1106                 goto abort_put_sess;
1107
1108         /* What header length is configured for this session? */
1109         hdr_len = pppol2tp_l2tp_header_len(session);
1110
1111         /* Check that there's enough headroom in the skb to insert IP,
1112          * UDP and L2TP and PPP headers. If not enough, expand it to
1113          * make room. Adjust truesize.
1114          */
1115         headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1116                 sizeof(struct udphdr) + hdr_len + sizeof(ppph);
1117         old_headroom = skb_headroom(skb);
1118         if (skb_cow_head(skb, headroom))
1119                 goto abort_put_sess_tun;
1120
1121         new_headroom = skb_headroom(skb);
1122         skb_orphan(skb);
1123         skb->truesize += new_headroom - old_headroom;
1124
1125         /* Setup PPP header */
1126         __skb_push(skb, sizeof(ppph));
1127         skb->data[0] = ppph[0];
1128         skb->data[1] = ppph[1];
1129
1130         /* Setup L2TP header */
1131         pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
1132
1133         udp_len = sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len;
1134
1135         /* Setup UDP header */
1136         inet = inet_sk(sk_tun);
1137         __skb_push(skb, sizeof(*uh));
1138         skb_reset_transport_header(skb);
1139         uh = udp_hdr(skb);
1140         uh->source = inet->sport;
1141         uh->dest = inet->dport;
1142         uh->len = htons(udp_len);
1143         uh->check = 0;
1144
1145         /* Debug */
1146         if (session->send_seq)
1147                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1148                        "%s: send %d bytes, ns=%hu\n", session->name,
1149                        data_len, session->ns - 1);
1150         else
1151                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1152                        "%s: send %d bytes\n", session->name, data_len);
1153
1154         if (session->debug & PPPOL2TP_MSG_DATA) {
1155                 int i;
1156                 unsigned char *datap = skb->data;
1157
1158                 printk(KERN_DEBUG "%s: xmit:", session->name);
1159                 for (i = 0; i < data_len; i++) {
1160                         printk(" %02X", *datap++);
1161                         if (i == 31) {
1162                                 printk(" ...");
1163                                 break;
1164                         }
1165                 }
1166                 printk("\n");
1167         }
1168
1169         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1170         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1171                               IPSKB_REROUTED);
1172         nf_reset(skb);
1173
1174         /* Get routing info from the tunnel socket */
1175         dst_release(skb->dst);
1176         skb->dst = dst_clone(__sk_dst_get(sk_tun));
1177         pppol2tp_skb_set_owner_w(skb, sk_tun);
1178
1179         /* Calculate UDP checksum if configured to do so */
1180         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
1181                 skb->ip_summed = CHECKSUM_NONE;
1182         else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
1183                 skb->ip_summed = CHECKSUM_COMPLETE;
1184                 csum = skb_checksum(skb, 0, udp_len, 0);
1185                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
1186                                               udp_len, IPPROTO_UDP, csum);
1187                 if (uh->check == 0)
1188                         uh->check = CSUM_MANGLED_0;
1189         } else {
1190                 skb->ip_summed = CHECKSUM_PARTIAL;
1191                 skb->csum_start = skb_transport_header(skb) - skb->head;
1192                 skb->csum_offset = offsetof(struct udphdr, check);
1193                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
1194                                                udp_len, IPPROTO_UDP, 0);
1195         }
1196
1197         /* Queue the packet to IP for output */
1198         len = skb->len;
1199         rc = ip_queue_xmit(skb, 1);
1200
1201         /* Update stats */
1202         if (rc >= 0) {
1203                 tunnel->stats.tx_packets++;
1204                 tunnel->stats.tx_bytes += len;
1205                 session->stats.tx_packets++;
1206                 session->stats.tx_bytes += len;
1207         } else {
1208                 tunnel->stats.tx_errors++;
1209                 session->stats.tx_errors++;
1210         }
1211
1212         sock_put(sk_tun);
1213         sock_put(sk);
1214         return 1;
1215
1216 abort_put_sess_tun:
1217         sock_put(sk_tun);
1218 abort_put_sess:
1219         sock_put(sk);
1220 abort:
1221         /* Free the original skb */
1222         kfree_skb(skb);
1223         return 1;
1224 }
1225
1226 /*****************************************************************************
1227  * Session (and tunnel control) socket create/destroy.
1228  *****************************************************************************/
1229
1230 /* When the tunnel UDP socket is closed, all the attached sockets need to go
1231  * too.
1232  */
1233 static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel)
1234 {
1235         int hash;
1236         struct hlist_node *walk;
1237         struct hlist_node *tmp;
1238         struct pppol2tp_session *session;
1239         struct sock *sk;
1240
1241         if (tunnel == NULL)
1242                 BUG();
1243
1244         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1245                "%s: closing all sessions...\n", tunnel->name);
1246
1247         write_lock_bh(&tunnel->hlist_lock);
1248         for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) {
1249 again:
1250                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1251                         struct sk_buff *skb;
1252
1253                         session = hlist_entry(walk, struct pppol2tp_session, hlist);
1254
1255                         sk = session->sock;
1256
1257                         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1258                                "%s: closing session\n", session->name);
1259
1260                         hlist_del_init(&session->hlist);
1261
1262                         /* Since we should hold the sock lock while
1263                          * doing any unbinding, we need to release the
1264                          * lock we're holding before taking that lock.
1265                          * Hold a reference to the sock so it doesn't
1266                          * disappear as we're jumping between locks.
1267                          */
1268                         sock_hold(sk);
1269                         write_unlock_bh(&tunnel->hlist_lock);
1270                         lock_sock(sk);
1271
1272                         if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
1273                                 pppox_unbind_sock(sk);
1274                                 sk->sk_state = PPPOX_DEAD;
1275                                 sk->sk_state_change(sk);
1276                         }
1277
1278                         /* Purge any queued data */
1279                         skb_queue_purge(&sk->sk_receive_queue);
1280                         skb_queue_purge(&sk->sk_write_queue);
1281                         while ((skb = skb_dequeue(&session->reorder_q))) {
1282                                 kfree_skb(skb);
1283                                 sock_put(sk);
1284                         }
1285
1286                         release_sock(sk);
1287                         sock_put(sk);
1288
1289                         /* Now restart from the beginning of this hash
1290                          * chain.  We always remove a session from the
1291                          * list so we are guaranteed to make forward
1292                          * progress.
1293                          */
1294                         write_lock_bh(&tunnel->hlist_lock);
1295                         goto again;
1296                 }
1297         }
1298         write_unlock_bh(&tunnel->hlist_lock);
1299 }
1300
1301 /* Really kill the tunnel.
1302  * Come here only when all sessions have been cleared from the tunnel.
1303  */
1304 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
1305 {
1306         struct pppol2tp_net *pn = pppol2tp_pernet(tunnel->pppol2tp_net);
1307
1308         /* Remove from socket list */
1309         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1310         list_del_init(&tunnel->list);
1311         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1312
1313         atomic_dec(&pppol2tp_tunnel_count);
1314         kfree(tunnel);
1315 }
1316
1317 /* Tunnel UDP socket destruct hook.
1318  * The tunnel context is deleted only when all session sockets have been
1319  * closed.
1320  */
1321 static void pppol2tp_tunnel_destruct(struct sock *sk)
1322 {
1323         struct pppol2tp_tunnel *tunnel;
1324
1325         tunnel = sk->sk_user_data;
1326         if (tunnel == NULL)
1327                 goto end;
1328
1329         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1330                "%s: closing...\n", tunnel->name);
1331
1332         /* Close all sessions */
1333         pppol2tp_tunnel_closeall(tunnel);
1334
1335         /* No longer an encapsulation socket. See net/ipv4/udp.c */
1336         (udp_sk(sk))->encap_type = 0;
1337         (udp_sk(sk))->encap_rcv = NULL;
1338
1339         /* Remove hooks into tunnel socket */
1340         tunnel->sock = NULL;
1341         sk->sk_destruct = tunnel->old_sk_destruct;
1342         sk->sk_user_data = NULL;
1343
1344         /* Call original (UDP) socket descructor */
1345         if (sk->sk_destruct != NULL)
1346                 (*sk->sk_destruct)(sk);
1347
1348         pppol2tp_tunnel_dec_refcount(tunnel);
1349
1350 end:
1351         return;
1352 }
1353
1354 /* Really kill the session socket. (Called from sock_put() if
1355  * refcnt == 0.)
1356  */
1357 static void pppol2tp_session_destruct(struct sock *sk)
1358 {
1359         struct pppol2tp_session *session = NULL;
1360
1361         if (sk->sk_user_data != NULL) {
1362                 struct pppol2tp_tunnel *tunnel;
1363
1364                 session = sk->sk_user_data;
1365                 if (session == NULL)
1366                         goto out;
1367
1368                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
1369
1370                 /* Don't use pppol2tp_sock_to_tunnel() here to
1371                  * get the tunnel context because the tunnel
1372                  * socket might have already been closed (its
1373                  * sk->sk_user_data will be NULL) so use the
1374                  * session's private tunnel ptr instead.
1375                  */
1376                 tunnel = session->tunnel;
1377                 if (tunnel != NULL) {
1378                         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1379
1380                         /* If session_id is zero, this is a null
1381                          * session context, which was created for a
1382                          * socket that is being used only to manage
1383                          * tunnels.
1384                          */
1385                         if (session->tunnel_addr.s_session != 0) {
1386                                 /* Delete the session socket from the
1387                                  * hash
1388                                  */
1389                                 write_lock_bh(&tunnel->hlist_lock);
1390                                 hlist_del_init(&session->hlist);
1391                                 write_unlock_bh(&tunnel->hlist_lock);
1392
1393                                 atomic_dec(&pppol2tp_session_count);
1394                         }
1395
1396                         /* This will delete the tunnel context if this
1397                          * is the last session on the tunnel.
1398                          */
1399                         session->tunnel = NULL;
1400                         session->tunnel_sock = NULL;
1401                         pppol2tp_tunnel_dec_refcount(tunnel);
1402                 }
1403         }
1404
1405         kfree(session);
1406 out:
1407         return;
1408 }
1409
1410 /* Called when the PPPoX socket (session) is closed.
1411  */
1412 static int pppol2tp_release(struct socket *sock)
1413 {
1414         struct sock *sk = sock->sk;
1415         struct pppol2tp_session *session;
1416         int error;
1417
1418         if (!sk)
1419                 return 0;
1420
1421         error = -EBADF;
1422         lock_sock(sk);
1423         if (sock_flag(sk, SOCK_DEAD) != 0)
1424                 goto error;
1425
1426         pppox_unbind_sock(sk);
1427
1428         /* Signal the death of the socket. */
1429         sk->sk_state = PPPOX_DEAD;
1430         sock_orphan(sk);
1431         sock->sk = NULL;
1432
1433         session = pppol2tp_sock_to_session(sk);
1434
1435         /* Purge any queued data */
1436         skb_queue_purge(&sk->sk_receive_queue);
1437         skb_queue_purge(&sk->sk_write_queue);
1438         if (session != NULL) {
1439                 struct sk_buff *skb;
1440                 while ((skb = skb_dequeue(&session->reorder_q))) {
1441                         kfree_skb(skb);
1442                         sock_put(sk);
1443                 }
1444                 sock_put(sk);
1445         }
1446
1447         release_sock(sk);
1448
1449         /* This will delete the session context via
1450          * pppol2tp_session_destruct() if the socket's refcnt drops to
1451          * zero.
1452          */
1453         sock_put(sk);
1454
1455         return 0;
1456
1457 error:
1458         release_sock(sk);
1459         return error;
1460 }
1461
1462 /* Internal function to prepare a tunnel (UDP) socket to have PPPoX
1463  * sockets attached to it.
1464  */
1465 static struct sock *pppol2tp_prepare_tunnel_socket(struct net *net,
1466                                         int fd, u16 tunnel_id, int *error)
1467 {
1468         int err;
1469         struct socket *sock = NULL;
1470         struct sock *sk;
1471         struct pppol2tp_tunnel *tunnel;
1472         struct pppol2tp_net *pn;
1473         struct sock *ret = NULL;
1474
1475         /* Get the tunnel UDP socket from the fd, which was opened by
1476          * the userspace L2TP daemon.
1477          */
1478         err = -EBADF;
1479         sock = sockfd_lookup(fd, &err);
1480         if (!sock) {
1481                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1482                        "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1483                        tunnel_id, fd, err);
1484                 goto err;
1485         }
1486
1487         sk = sock->sk;
1488
1489         /* Quick sanity checks */
1490         err = -EPROTONOSUPPORT;
1491         if (sk->sk_protocol != IPPROTO_UDP) {
1492                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1493                        "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1494                        tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1495                 goto err;
1496         }
1497         err = -EAFNOSUPPORT;
1498         if (sock->ops->family != AF_INET) {
1499                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1500                        "tunl %hu: fd %d wrong family, got %d, expected %d\n",
1501                        tunnel_id, fd, sock->ops->family, AF_INET);
1502                 goto err;
1503         }
1504
1505         err = -ENOTCONN;
1506
1507         /* Check if this socket has already been prepped */
1508         tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;
1509         if (tunnel != NULL) {
1510                 /* User-data field already set */
1511                 err = -EBUSY;
1512                 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1513
1514                 /* This socket has already been prepped */
1515                 ret = tunnel->sock;
1516                 goto out;
1517         }
1518
1519         /* This socket is available and needs prepping. Create a new tunnel
1520          * context and init it.
1521          */
1522         sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL);
1523         if (sk->sk_user_data == NULL) {
1524                 err = -ENOMEM;
1525                 goto err;
1526         }
1527
1528         tunnel->magic = L2TP_TUNNEL_MAGIC;
1529         sprintf(&tunnel->name[0], "tunl %hu", tunnel_id);
1530
1531         tunnel->stats.tunnel_id = tunnel_id;
1532         tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS;
1533
1534         /* Hook on the tunnel socket destructor so that we can cleanup
1535          * if the tunnel socket goes away.
1536          */
1537         tunnel->old_sk_destruct = sk->sk_destruct;
1538         sk->sk_destruct = &pppol2tp_tunnel_destruct;
1539
1540         tunnel->sock = sk;
1541         sk->sk_allocation = GFP_ATOMIC;
1542
1543         /* Misc init */
1544         rwlock_init(&tunnel->hlist_lock);
1545
1546         /* The net we belong to */
1547         tunnel->pppol2tp_net = net;
1548         pn = pppol2tp_pernet(net);
1549
1550         /* Add tunnel to our list */
1551         INIT_LIST_HEAD(&tunnel->list);
1552         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1553         list_add(&tunnel->list, &pn->pppol2tp_tunnel_list);
1554         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1555         atomic_inc(&pppol2tp_tunnel_count);
1556
1557         /* Bump the reference count. The tunnel context is deleted
1558          * only when this drops to zero.
1559          */
1560         pppol2tp_tunnel_inc_refcount(tunnel);
1561
1562         /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1563         (udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP;
1564         (udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv;
1565
1566         ret = tunnel->sock;
1567
1568         *error = 0;
1569 out:
1570         if (sock)
1571                 sockfd_put(sock);
1572
1573         return ret;
1574
1575 err:
1576         *error = err;
1577         goto out;
1578 }
1579
1580 static struct proto pppol2tp_sk_proto = {
1581         .name     = "PPPOL2TP",
1582         .owner    = THIS_MODULE,
1583         .obj_size = sizeof(struct pppox_sock),
1584 };
1585
1586 /* socket() handler. Initialize a new struct sock.
1587  */
1588 static int pppol2tp_create(struct net *net, struct socket *sock)
1589 {
1590         int error = -ENOMEM;
1591         struct sock *sk;
1592
1593         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
1594         if (!sk)
1595                 goto out;
1596
1597         sock_init_data(sock, sk);
1598
1599         sock->state  = SS_UNCONNECTED;
1600         sock->ops    = &pppol2tp_ops;
1601
1602         sk->sk_backlog_rcv = pppol2tp_recv_core;
1603         sk->sk_protocol    = PX_PROTO_OL2TP;
1604         sk->sk_family      = PF_PPPOX;
1605         sk->sk_state       = PPPOX_NONE;
1606         sk->sk_type        = SOCK_STREAM;
1607         sk->sk_destruct    = pppol2tp_session_destruct;
1608
1609         error = 0;
1610
1611 out:
1612         return error;
1613 }
1614
1615 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
1616  */
1617 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
1618                             int sockaddr_len, int flags)
1619 {
1620         struct sock *sk = sock->sk;
1621         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
1622         struct pppox_sock *po = pppox_sk(sk);
1623         struct sock *tunnel_sock = NULL;
1624         struct pppol2tp_session *session = NULL;
1625         struct pppol2tp_tunnel *tunnel;
1626         struct dst_entry *dst;
1627         int error = 0;
1628
1629         lock_sock(sk);
1630
1631         error = -EINVAL;
1632         if (sp->sa_protocol != PX_PROTO_OL2TP)
1633                 goto end;
1634
1635         /* Check for already bound sockets */
1636         error = -EBUSY;
1637         if (sk->sk_state & PPPOX_CONNECTED)
1638                 goto end;
1639
1640         /* We don't supporting rebinding anyway */
1641         error = -EALREADY;
1642         if (sk->sk_user_data)
1643                 goto end; /* socket is already attached */
1644
1645         /* Don't bind if s_tunnel is 0 */
1646         error = -EINVAL;
1647         if (sp->pppol2tp.s_tunnel == 0)
1648                 goto end;
1649
1650         /* Special case: prepare tunnel socket if s_session and
1651          * d_session is 0. Otherwise look up tunnel using supplied
1652          * tunnel id.
1653          */
1654         if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
1655                 tunnel_sock = pppol2tp_prepare_tunnel_socket(sock_net(sk),
1656                                                              sp->pppol2tp.fd,
1657                                                              sp->pppol2tp.s_tunnel,
1658                                                              &error);
1659                 if (tunnel_sock == NULL)
1660                         goto end;
1661
1662                 tunnel = tunnel_sock->sk_user_data;
1663         } else {
1664                 tunnel = pppol2tp_tunnel_find(sock_net(sk), sp->pppol2tp.s_tunnel);
1665
1666                 /* Error if we can't find the tunnel */
1667                 error = -ENOENT;
1668                 if (tunnel == NULL)
1669                         goto end;
1670
1671                 tunnel_sock = tunnel->sock;
1672         }
1673
1674         /* Check that this session doesn't already exist */
1675         error = -EEXIST;
1676         session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session);
1677         if (session != NULL)
1678                 goto end;
1679
1680         /* Allocate and initialize a new session context. */
1681         session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL);
1682         if (session == NULL) {
1683                 error = -ENOMEM;
1684                 goto end;
1685         }
1686
1687         skb_queue_head_init(&session->reorder_q);
1688
1689         session->magic       = L2TP_SESSION_MAGIC;
1690         session->owner       = current->pid;
1691         session->sock        = sk;
1692         session->tunnel      = tunnel;
1693         session->tunnel_sock = tunnel_sock;
1694         session->tunnel_addr = sp->pppol2tp;
1695         sprintf(&session->name[0], "sess %hu/%hu",
1696                 session->tunnel_addr.s_tunnel,
1697                 session->tunnel_addr.s_session);
1698
1699         session->stats.tunnel_id  = session->tunnel_addr.s_tunnel;
1700         session->stats.session_id = session->tunnel_addr.s_session;
1701
1702         INIT_HLIST_NODE(&session->hlist);
1703
1704         /* Inherit debug options from tunnel */
1705         session->debug = tunnel->debug;
1706
1707         /* Default MTU must allow space for UDP/L2TP/PPP
1708          * headers.
1709          */
1710         session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
1711
1712         /* If PMTU discovery was enabled, use the MTU that was discovered */
1713         dst = sk_dst_get(sk);
1714         if (dst != NULL) {
1715                 u32 pmtu = dst_mtu(__sk_dst_get(sk));
1716                 if (pmtu != 0)
1717                         session->mtu = session->mru = pmtu -
1718                                 PPPOL2TP_HEADER_OVERHEAD;
1719                 dst_release(dst);
1720         }
1721
1722         /* Special case: if source & dest session_id == 0x0000, this socket is
1723          * being created to manage the tunnel. Don't add the session to the
1724          * session hash list, just set up the internal context for use by
1725          * ioctl() and sockopt() handlers.
1726          */
1727         if ((session->tunnel_addr.s_session == 0) &&
1728             (session->tunnel_addr.d_session == 0)) {
1729                 error = 0;
1730                 sk->sk_user_data = session;
1731                 goto out_no_ppp;
1732         }
1733
1734         /* Get tunnel context from the tunnel socket */
1735         tunnel = pppol2tp_sock_to_tunnel(tunnel_sock);
1736         if (tunnel == NULL) {
1737                 error = -EBADF;
1738                 goto end;
1739         }
1740
1741         /* Right now, because we don't have a way to push the incoming skb's
1742          * straight through the UDP layer, the only header we need to worry
1743          * about is the L2TP header. This size is different depending on
1744          * whether sequence numbers are enabled for the data channel.
1745          */
1746         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1747
1748         po->chan.private = sk;
1749         po->chan.ops     = &pppol2tp_chan_ops;
1750         po->chan.mtu     = session->mtu;
1751
1752         error = ppp_register_net_channel(sock_net(sk), &po->chan);
1753         if (error)
1754                 goto end_put_tun;
1755
1756         /* This is how we get the session context from the socket. */
1757         sk->sk_user_data = session;
1758
1759         /* Add session to the tunnel's hash list */
1760         write_lock_bh(&tunnel->hlist_lock);
1761         hlist_add_head(&session->hlist,
1762                        pppol2tp_session_id_hash(tunnel,
1763                                                 session->tunnel_addr.s_session));
1764         write_unlock_bh(&tunnel->hlist_lock);
1765
1766         atomic_inc(&pppol2tp_session_count);
1767
1768 out_no_ppp:
1769         pppol2tp_tunnel_inc_refcount(tunnel);
1770         sk->sk_state = PPPOX_CONNECTED;
1771         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1772                "%s: created\n", session->name);
1773
1774 end_put_tun:
1775         sock_put(tunnel_sock);
1776 end:
1777         release_sock(sk);
1778
1779         if (error != 0) {
1780                 if (session)
1781                         PRINTK(session->debug,
1782                                 PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1783                                 "%s: connect failed: %d\n",
1784                                 session->name, error);
1785                 else
1786                         PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1787                                 "connect failed: %d\n", error);
1788         }
1789
1790         return error;
1791 }
1792
1793 /* getname() support.
1794  */
1795 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
1796                             int *usockaddr_len, int peer)
1797 {
1798         int len = sizeof(struct sockaddr_pppol2tp);
1799         struct sockaddr_pppol2tp sp;
1800         int error = 0;
1801         struct pppol2tp_session *session;
1802
1803         error = -ENOTCONN;
1804         if (sock->sk->sk_state != PPPOX_CONNECTED)
1805                 goto end;
1806
1807         session = pppol2tp_sock_to_session(sock->sk);
1808         if (session == NULL) {
1809                 error = -EBADF;
1810                 goto end;
1811         }
1812
1813         sp.sa_family    = AF_PPPOX;
1814         sp.sa_protocol  = PX_PROTO_OL2TP;
1815         memcpy(&sp.pppol2tp, &session->tunnel_addr,
1816                sizeof(struct pppol2tp_addr));
1817
1818         memcpy(uaddr, &sp, len);
1819
1820         *usockaddr_len = len;
1821
1822         error = 0;
1823         sock_put(sock->sk);
1824
1825 end:
1826         return error;
1827 }
1828
1829 /****************************************************************************
1830  * ioctl() handlers.
1831  *
1832  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1833  * sockets. However, in order to control kernel tunnel features, we allow
1834  * userspace to create a special "tunnel" PPPoX socket which is used for
1835  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
1836  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1837  * calls.
1838  ****************************************************************************/
1839
1840 /* Session ioctl helper.
1841  */
1842 static int pppol2tp_session_ioctl(struct pppol2tp_session *session,
1843                                   unsigned int cmd, unsigned long arg)
1844 {
1845         struct ifreq ifr;
1846         int err = 0;
1847         struct sock *sk = session->sock;
1848         int val = (int) arg;
1849
1850         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1851                "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1852                session->name, cmd, arg);
1853
1854         sock_hold(sk);
1855
1856         switch (cmd) {
1857         case SIOCGIFMTU:
1858                 err = -ENXIO;
1859                 if (!(sk->sk_state & PPPOX_CONNECTED))
1860                         break;
1861
1862                 err = -EFAULT;
1863                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1864                         break;
1865                 ifr.ifr_mtu = session->mtu;
1866                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1867                         break;
1868
1869                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1870                        "%s: get mtu=%d\n", session->name, session->mtu);
1871                 err = 0;
1872                 break;
1873
1874         case SIOCSIFMTU:
1875                 err = -ENXIO;
1876                 if (!(sk->sk_state & PPPOX_CONNECTED))
1877                         break;
1878
1879                 err = -EFAULT;
1880                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1881                         break;
1882
1883                 session->mtu = ifr.ifr_mtu;
1884
1885                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1886                        "%s: set mtu=%d\n", session->name, session->mtu);
1887                 err = 0;
1888                 break;
1889
1890         case PPPIOCGMRU:
1891                 err = -ENXIO;
1892                 if (!(sk->sk_state & PPPOX_CONNECTED))
1893                         break;
1894
1895                 err = -EFAULT;
1896                 if (put_user(session->mru, (int __user *) arg))
1897                         break;
1898
1899                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1900                        "%s: get mru=%d\n", session->name, session->mru);
1901                 err = 0;
1902                 break;
1903
1904         case PPPIOCSMRU:
1905                 err = -ENXIO;
1906                 if (!(sk->sk_state & PPPOX_CONNECTED))
1907                         break;
1908
1909                 err = -EFAULT;
1910                 if (get_user(val,(int __user *) arg))
1911                         break;
1912
1913                 session->mru = val;
1914                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1915                        "%s: set mru=%d\n", session->name, session->mru);
1916                 err = 0;
1917                 break;
1918
1919         case PPPIOCGFLAGS:
1920                 err = -EFAULT;
1921                 if (put_user(session->flags, (int __user *) arg))
1922                         break;
1923
1924                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1925                        "%s: get flags=%d\n", session->name, session->flags);
1926                 err = 0;
1927                 break;
1928
1929         case PPPIOCSFLAGS:
1930                 err = -EFAULT;
1931                 if (get_user(val, (int __user *) arg))
1932                         break;
1933                 session->flags = val;
1934                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1935                        "%s: set flags=%d\n", session->name, session->flags);
1936                 err = 0;
1937                 break;
1938
1939         case PPPIOCGL2TPSTATS:
1940                 err = -ENXIO;
1941                 if (!(sk->sk_state & PPPOX_CONNECTED))
1942                         break;
1943
1944                 if (copy_to_user((void __user *) arg, &session->stats,
1945                                  sizeof(session->stats)))
1946                         break;
1947                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1948                        "%s: get L2TP stats\n", session->name);
1949                 err = 0;
1950                 break;
1951
1952         default:
1953                 err = -ENOSYS;
1954                 break;
1955         }
1956
1957         sock_put(sk);
1958
1959         return err;
1960 }
1961
1962 /* Tunnel ioctl helper.
1963  *
1964  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1965  * specifies a session_id, the session ioctl handler is called. This allows an
1966  * application to retrieve session stats via a tunnel socket.
1967  */
1968 static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel,
1969                                  unsigned int cmd, unsigned long arg)
1970 {
1971         int err = 0;
1972         struct sock *sk = tunnel->sock;
1973         struct pppol2tp_ioc_stats stats_req;
1974
1975         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1976                "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name,
1977                cmd, arg);
1978
1979         sock_hold(sk);
1980
1981         switch (cmd) {
1982         case PPPIOCGL2TPSTATS:
1983                 err = -ENXIO;
1984                 if (!(sk->sk_state & PPPOX_CONNECTED))
1985                         break;
1986
1987                 if (copy_from_user(&stats_req, (void __user *) arg,
1988                                    sizeof(stats_req))) {
1989                         err = -EFAULT;
1990                         break;
1991                 }
1992                 if (stats_req.session_id != 0) {
1993                         /* resend to session ioctl handler */
1994                         struct pppol2tp_session *session =
1995                                 pppol2tp_session_find(tunnel, stats_req.session_id);
1996                         if (session != NULL)
1997                                 err = pppol2tp_session_ioctl(session, cmd, arg);
1998                         else
1999                                 err = -EBADR;
2000                         break;
2001                 }
2002 #ifdef CONFIG_XFRM
2003                 tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
2004 #endif
2005                 if (copy_to_user((void __user *) arg, &tunnel->stats,
2006                                  sizeof(tunnel->stats))) {
2007                         err = -EFAULT;
2008                         break;
2009                 }
2010                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2011                        "%s: get L2TP stats\n", tunnel->name);
2012                 err = 0;
2013                 break;
2014
2015         default:
2016                 err = -ENOSYS;
2017                 break;
2018         }
2019
2020         sock_put(sk);
2021
2022         return err;
2023 }
2024
2025 /* Main ioctl() handler.
2026  * Dispatch to tunnel or session helpers depending on the socket.
2027  */
2028 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
2029                           unsigned long arg)
2030 {
2031         struct sock *sk = sock->sk;
2032         struct pppol2tp_session *session;
2033         struct pppol2tp_tunnel *tunnel;
2034         int err;
2035
2036         if (!sk)
2037                 return 0;
2038
2039         err = -EBADF;
2040         if (sock_flag(sk, SOCK_DEAD) != 0)
2041                 goto end;
2042
2043         err = -ENOTCONN;
2044         if ((sk->sk_user_data == NULL) ||
2045             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
2046                 goto end;
2047
2048         /* Get session context from the socket */
2049         err = -EBADF;
2050         session = pppol2tp_sock_to_session(sk);
2051         if (session == NULL)
2052                 goto end;
2053
2054         /* Special case: if session's session_id is zero, treat ioctl as a
2055          * tunnel ioctl
2056          */
2057         if ((session->tunnel_addr.s_session == 0) &&
2058             (session->tunnel_addr.d_session == 0)) {
2059                 err = -EBADF;
2060                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2061                 if (tunnel == NULL)
2062                         goto end_put_sess;
2063
2064                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
2065                 sock_put(session->tunnel_sock);
2066                 goto end_put_sess;
2067         }
2068
2069         err = pppol2tp_session_ioctl(session, cmd, arg);
2070
2071 end_put_sess:
2072         sock_put(sk);
2073 end:
2074         return err;
2075 }
2076
2077 /*****************************************************************************
2078  * setsockopt() / getsockopt() support.
2079  *
2080  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
2081  * sockets. In order to control kernel tunnel features, we allow userspace to
2082  * create a special "tunnel" PPPoX socket which is used for control only.
2083  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
2084  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
2085  *****************************************************************************/
2086
2087 /* Tunnel setsockopt() helper.
2088  */
2089 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
2090                                       struct pppol2tp_tunnel *tunnel,
2091                                       int optname, int val)
2092 {
2093         int err = 0;
2094
2095         switch (optname) {
2096         case PPPOL2TP_SO_DEBUG:
2097                 tunnel->debug = val;
2098                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2099                        "%s: set debug=%x\n", tunnel->name, tunnel->debug);
2100                 break;
2101
2102         default:
2103                 err = -ENOPROTOOPT;
2104                 break;
2105         }
2106
2107         return err;
2108 }
2109
2110 /* Session setsockopt helper.
2111  */
2112 static int pppol2tp_session_setsockopt(struct sock *sk,
2113                                        struct pppol2tp_session *session,
2114                                        int optname, int val)
2115 {
2116         int err = 0;
2117
2118         switch (optname) {
2119         case PPPOL2TP_SO_RECVSEQ:
2120                 if ((val != 0) && (val != 1)) {
2121                         err = -EINVAL;
2122                         break;
2123                 }
2124                 session->recv_seq = val ? -1 : 0;
2125                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2126                        "%s: set recv_seq=%d\n", session->name,
2127                        session->recv_seq);
2128                 break;
2129
2130         case PPPOL2TP_SO_SENDSEQ:
2131                 if ((val != 0) && (val != 1)) {
2132                         err = -EINVAL;
2133                         break;
2134                 }
2135                 session->send_seq = val ? -1 : 0;
2136                 {
2137                         struct sock *ssk      = session->sock;
2138                         struct pppox_sock *po = pppox_sk(ssk);
2139                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
2140                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
2141                 }
2142                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2143                        "%s: set send_seq=%d\n", session->name, session->send_seq);
2144                 break;
2145
2146         case PPPOL2TP_SO_LNSMODE:
2147                 if ((val != 0) && (val != 1)) {
2148                         err = -EINVAL;
2149                         break;
2150                 }
2151                 session->lns_mode = val ? -1 : 0;
2152                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2153                        "%s: set lns_mode=%d\n", session->name,
2154                        session->lns_mode);
2155                 break;
2156
2157         case PPPOL2TP_SO_DEBUG:
2158                 session->debug = val;
2159                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2160                        "%s: set debug=%x\n", session->name, session->debug);
2161                 break;
2162
2163         case PPPOL2TP_SO_REORDERTO:
2164                 session->reorder_timeout = msecs_to_jiffies(val);
2165                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2166                        "%s: set reorder_timeout=%d\n", session->name,
2167                        session->reorder_timeout);
2168                 break;
2169
2170         default:
2171                 err = -ENOPROTOOPT;
2172                 break;
2173         }
2174
2175         return err;
2176 }
2177
2178 /* Main setsockopt() entry point.
2179  * Does API checks, then calls either the tunnel or session setsockopt
2180  * handler, according to whether the PPPoL2TP socket is a for a regular
2181  * session or the special tunnel type.
2182  */
2183 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
2184                                char __user *optval, int optlen)
2185 {
2186         struct sock *sk = sock->sk;
2187         struct pppol2tp_session *session = sk->sk_user_data;
2188         struct pppol2tp_tunnel *tunnel;
2189         int val;
2190         int err;
2191
2192         if (level != SOL_PPPOL2TP)
2193                 return udp_prot.setsockopt(sk, level, optname, optval, optlen);
2194
2195         if (optlen < sizeof(int))
2196                 return -EINVAL;
2197
2198         if (get_user(val, (int __user *)optval))
2199                 return -EFAULT;
2200
2201         err = -ENOTCONN;
2202         if (sk->sk_user_data == NULL)
2203                 goto end;
2204
2205         /* Get session context from the socket */
2206         err = -EBADF;
2207         session = pppol2tp_sock_to_session(sk);
2208         if (session == NULL)
2209                 goto end;
2210
2211         /* Special case: if session_id == 0x0000, treat as operation on tunnel
2212          */
2213         if ((session->tunnel_addr.s_session == 0) &&
2214             (session->tunnel_addr.d_session == 0)) {
2215                 err = -EBADF;
2216                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2217                 if (tunnel == NULL)
2218                         goto end_put_sess;
2219
2220                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
2221                 sock_put(session->tunnel_sock);
2222         } else
2223                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
2224
2225         err = 0;
2226
2227 end_put_sess:
2228         sock_put(sk);
2229 end:
2230         return err;
2231 }
2232
2233 /* Tunnel getsockopt helper. Called with sock locked.
2234  */
2235 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
2236                                       struct pppol2tp_tunnel *tunnel,
2237                                       int optname, int *val)
2238 {
2239         int err = 0;
2240
2241         switch (optname) {
2242         case PPPOL2TP_SO_DEBUG:
2243                 *val = tunnel->debug;
2244                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2245                        "%s: get debug=%x\n", tunnel->name, tunnel->debug);
2246                 break;
2247
2248         default:
2249                 err = -ENOPROTOOPT;
2250                 break;
2251         }
2252
2253         return err;
2254 }
2255
2256 /* Session getsockopt helper. Called with sock locked.
2257  */
2258 static int pppol2tp_session_getsockopt(struct sock *sk,
2259                                        struct pppol2tp_session *session,
2260                                        int optname, int *val)
2261 {
2262         int err = 0;
2263
2264         switch (optname) {
2265         case PPPOL2TP_SO_RECVSEQ:
2266                 *val = session->recv_seq;
2267                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2268                        "%s: get recv_seq=%d\n", session->name, *val);
2269                 break;
2270
2271         case PPPOL2TP_SO_SENDSEQ:
2272                 *val = session->send_seq;
2273                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2274                        "%s: get send_seq=%d\n", session->name, *val);
2275                 break;
2276
2277         case PPPOL2TP_SO_LNSMODE:
2278                 *val = session->lns_mode;
2279                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2280                        "%s: get lns_mode=%d\n", session->name, *val);
2281                 break;
2282
2283         case PPPOL2TP_SO_DEBUG:
2284                 *val = session->debug;
2285                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2286                        "%s: get debug=%d\n", session->name, *val);
2287                 break;
2288
2289         case PPPOL2TP_SO_REORDERTO:
2290                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
2291                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2292                        "%s: get reorder_timeout=%d\n", session->name, *val);
2293                 break;
2294
2295         default:
2296                 err = -ENOPROTOOPT;
2297         }
2298
2299         return err;
2300 }
2301
2302 /* Main getsockopt() entry point.
2303  * Does API checks, then calls either the tunnel or session getsockopt
2304  * handler, according to whether the PPPoX socket is a for a regular session
2305  * or the special tunnel type.
2306  */
2307 static int pppol2tp_getsockopt(struct socket *sock, int level,
2308                                int optname, char __user *optval, int __user *optlen)
2309 {
2310         struct sock *sk = sock->sk;
2311         struct pppol2tp_session *session = sk->sk_user_data;
2312         struct pppol2tp_tunnel *tunnel;
2313         int val, len;
2314         int err;
2315
2316         if (level != SOL_PPPOL2TP)
2317                 return udp_prot.getsockopt(sk, level, optname, optval, optlen);
2318
2319         if (get_user(len, (int __user *) optlen))
2320                 return -EFAULT;
2321
2322         len = min_t(unsigned int, len, sizeof(int));
2323
2324         if (len < 0)
2325                 return -EINVAL;
2326
2327         err = -ENOTCONN;
2328         if (sk->sk_user_data == NULL)
2329                 goto end;
2330
2331         /* Get the session context */
2332         err = -EBADF;
2333         session = pppol2tp_sock_to_session(sk);
2334         if (session == NULL)
2335                 goto end;
2336
2337         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
2338         if ((session->tunnel_addr.s_session == 0) &&
2339             (session->tunnel_addr.d_session == 0)) {
2340                 err = -EBADF;
2341                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2342                 if (tunnel == NULL)
2343                         goto end_put_sess;
2344
2345                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
2346                 sock_put(session->tunnel_sock);
2347         } else
2348                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
2349
2350         err = -EFAULT;
2351         if (put_user(len, (int __user *) optlen))
2352                 goto end_put_sess;
2353
2354         if (copy_to_user((void __user *) optval, &val, len))
2355                 goto end_put_sess;
2356
2357         err = 0;
2358
2359 end_put_sess:
2360         sock_put(sk);
2361 end:
2362         return err;
2363 }
2364
2365 /*****************************************************************************
2366  * /proc filesystem for debug
2367  *****************************************************************************/
2368
2369 #ifdef CONFIG_PROC_FS
2370
2371 #include <linux/seq_file.h>
2372
2373 struct pppol2tp_seq_data {
2374         struct seq_net_private p;
2375         struct pppol2tp_tunnel *tunnel;         /* current tunnel */
2376         struct pppol2tp_session *session;       /* NULL means get first session in tunnel */
2377 };
2378
2379 static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
2380 {
2381         struct pppol2tp_session *session = NULL;
2382         struct hlist_node *walk;
2383         int found = 0;
2384         int next = 0;
2385         int i;
2386
2387         read_lock_bh(&tunnel->hlist_lock);
2388         for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) {
2389                 hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) {
2390                         if (curr == NULL) {
2391                                 found = 1;
2392                                 goto out;
2393                         }
2394                         if (session == curr) {
2395                                 next = 1;
2396                                 continue;
2397                         }
2398                         if (next) {
2399                                 found = 1;
2400                                 goto out;
2401                         }
2402                 }
2403         }
2404 out:
2405         read_unlock_bh(&tunnel->hlist_lock);
2406         if (!found)
2407                 session = NULL;
2408
2409         return session;
2410 }
2411
2412 static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_net *pn,
2413                                            struct pppol2tp_tunnel *curr)
2414 {
2415         struct pppol2tp_tunnel *tunnel = NULL;
2416
2417         read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
2418         if (list_is_last(&curr->list, &pn->pppol2tp_tunnel_list)) {
2419                 goto out;
2420         }
2421         tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
2422 out:
2423         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
2424
2425         return tunnel;
2426 }
2427
2428 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
2429 {
2430         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
2431         struct pppol2tp_net *pn;
2432         loff_t pos = *offs;
2433
2434         if (!pos)
2435                 goto out;
2436
2437         BUG_ON(m->private == NULL);
2438         pd = m->private;
2439         pn = pppol2tp_pernet(seq_file_net(m));
2440
2441         if (pd->tunnel == NULL) {
2442                 if (!list_empty(&pn->pppol2tp_tunnel_list))
2443                         pd->tunnel = list_entry(pn->pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
2444         } else {
2445                 pd->session = next_session(pd->tunnel, pd->session);
2446                 if (pd->session == NULL) {
2447                         pd->tunnel = next_tunnel(pn, pd->tunnel);
2448                 }
2449         }
2450
2451         /* NULL tunnel and session indicates end of list */
2452         if ((pd->tunnel == NULL) && (pd->session == NULL))
2453                 pd = NULL;
2454
2455 out:
2456         return pd;
2457 }
2458
2459 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
2460 {
2461         (*pos)++;
2462         return NULL;
2463 }
2464
2465 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
2466 {
2467         /* nothing to do */
2468 }
2469
2470 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
2471 {
2472         struct pppol2tp_tunnel *tunnel = v;
2473
2474         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
2475                    tunnel->name,
2476                    (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N',
2477                    atomic_read(&tunnel->ref_count) - 1);
2478         seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n",
2479                    tunnel->debug,
2480                    (unsigned long long)tunnel->stats.tx_packets,
2481                    (unsigned long long)tunnel->stats.tx_bytes,
2482                    (unsigned long long)tunnel->stats.tx_errors,
2483                    (unsigned long long)tunnel->stats.rx_packets,
2484                    (unsigned long long)tunnel->stats.rx_bytes,
2485                    (unsigned long long)tunnel->stats.rx_errors);
2486 }
2487
2488 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
2489 {
2490         struct pppol2tp_session *session = v;
2491
2492         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
2493                    "%04X/%04X %d %c\n",
2494                    session->name,
2495                    ntohl(session->tunnel_addr.addr.sin_addr.s_addr),
2496                    ntohs(session->tunnel_addr.addr.sin_port),
2497                    session->tunnel_addr.s_tunnel,
2498                    session->tunnel_addr.s_session,
2499                    session->tunnel_addr.d_tunnel,
2500                    session->tunnel_addr.d_session,
2501                    session->sock->sk_state,
2502                    (session == session->sock->sk_user_data) ?
2503                    'Y' : 'N');
2504         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
2505                    session->mtu, session->mru,
2506                    session->recv_seq ? 'R' : '-',
2507                    session->send_seq ? 'S' : '-',
2508                    session->lns_mode ? "LNS" : "LAC",
2509                    session->debug,
2510                    jiffies_to_msecs(session->reorder_timeout));
2511         seq_printf(m, "   %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n",
2512                    session->nr, session->ns,
2513                    (unsigned long long)session->stats.tx_packets,
2514                    (unsigned long long)session->stats.tx_bytes,
2515                    (unsigned long long)session->stats.tx_errors,
2516                    (unsigned long long)session->stats.rx_packets,
2517                    (unsigned long long)session->stats.rx_bytes,
2518                    (unsigned long long)session->stats.rx_errors);
2519 }
2520
2521 static int pppol2tp_seq_show(struct seq_file *m, void *v)
2522 {
2523         struct pppol2tp_seq_data *pd = v;
2524
2525         /* display header on line 1 */
2526         if (v == SEQ_START_TOKEN) {
2527                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
2528                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
2529                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2530                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
2531                          "dest-tid/sid state user-data-ok\n");
2532                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
2533                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2534                 goto out;
2535         }
2536
2537         /* Show the tunnel or session context.
2538          */
2539         if (pd->session == NULL)
2540                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
2541         else
2542                 pppol2tp_seq_session_show(m, pd->session);
2543
2544 out:
2545         return 0;
2546 }
2547
2548 static const struct seq_operations pppol2tp_seq_ops = {
2549         .start          = pppol2tp_seq_start,
2550         .next           = pppol2tp_seq_next,
2551         .stop           = pppol2tp_seq_stop,
2552         .show           = pppol2tp_seq_show,
2553 };
2554
2555 /* Called when our /proc file is opened. We allocate data for use when
2556  * iterating our tunnel / session contexts and store it in the private
2557  * data of the seq_file.
2558  */
2559 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
2560 {
2561         return seq_open_net(inode, file, &pppol2tp_seq_ops,
2562                             sizeof(struct pppol2tp_seq_data));
2563 }
2564
2565 static const struct file_operations pppol2tp_proc_fops = {
2566         .owner          = THIS_MODULE,
2567         .open           = pppol2tp_proc_open,
2568         .read           = seq_read,
2569         .llseek         = seq_lseek,
2570         .release        = seq_release_net,
2571 };
2572
2573 #endif /* CONFIG_PROC_FS */
2574
2575 /*****************************************************************************
2576  * Init and cleanup
2577  *****************************************************************************/
2578
2579 static struct proto_ops pppol2tp_ops = {
2580         .family         = AF_PPPOX,
2581         .owner          = THIS_MODULE,
2582         .release        = pppol2tp_release,
2583         .bind           = sock_no_bind,
2584         .connect        = pppol2tp_connect,
2585         .socketpair     = sock_no_socketpair,
2586         .accept         = sock_no_accept,
2587         .getname        = pppol2tp_getname,
2588         .poll           = datagram_poll,
2589         .listen         = sock_no_listen,
2590         .shutdown       = sock_no_shutdown,
2591         .setsockopt     = pppol2tp_setsockopt,
2592         .getsockopt     = pppol2tp_getsockopt,
2593         .sendmsg        = pppol2tp_sendmsg,
2594         .recvmsg        = pppol2tp_recvmsg,
2595         .mmap           = sock_no_mmap,
2596         .ioctl          = pppox_ioctl,
2597 };
2598
2599 static struct pppox_proto pppol2tp_proto = {
2600         .create         = pppol2tp_create,
2601         .ioctl          = pppol2tp_ioctl
2602 };
2603
2604 static __net_init int pppol2tp_init_net(struct net *net)
2605 {
2606         struct pppol2tp_net *pn;
2607         struct proc_dir_entry *pde;
2608         int err;
2609
2610         pn = kzalloc(sizeof(*pn), GFP_KERNEL);
2611         if (!pn)
2612                 return -ENOMEM;
2613
2614         INIT_LIST_HEAD(&pn->pppol2tp_tunnel_list);
2615         rwlock_init(&pn->pppol2tp_tunnel_list_lock);
2616
2617         err = net_assign_generic(net, pppol2tp_net_id, pn);
2618         if (err)
2619                 goto out;
2620
2621         pde = proc_net_fops_create(net, "pppol2tp", S_IRUGO, &pppol2tp_proc_fops);
2622 #ifdef CONFIG_PROC_FS
2623         if (!pde) {
2624                 err = -ENOMEM;
2625                 goto out;
2626         }
2627 #endif
2628
2629         return 0;
2630
2631 out:
2632         kfree(pn);
2633         return err;
2634 }
2635
2636 static __net_exit void pppol2tp_exit_net(struct net *net)
2637 {
2638         struct pppoe_net *pn;
2639
2640         proc_net_remove(net, "pppol2tp");
2641         pn = net_generic(net, pppol2tp_net_id);
2642         /*
2643          * if someone has cached our net then
2644          * further net_generic call will return NULL
2645          */
2646         net_assign_generic(net, pppol2tp_net_id, NULL);
2647         kfree(pn);
2648 }
2649
2650 static struct pernet_operations pppol2tp_net_ops = {
2651         .init = pppol2tp_init_net,
2652         .exit = pppol2tp_exit_net,
2653 };
2654
2655 static int __init pppol2tp_init(void)
2656 {
2657         int err;
2658
2659         err = proto_register(&pppol2tp_sk_proto, 0);
2660         if (err)
2661                 goto out;
2662         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
2663         if (err)
2664                 goto out_unregister_pppol2tp_proto;
2665
2666         err = register_pernet_gen_device(&pppol2tp_net_id, &pppol2tp_net_ops);
2667         if (err)
2668                 goto out_unregister_pppox_proto;
2669
2670         printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
2671                PPPOL2TP_DRV_VERSION);
2672
2673 out:
2674         return err;
2675 out_unregister_pppox_proto:
2676         unregister_pppox_proto(PX_PROTO_OL2TP);
2677 out_unregister_pppol2tp_proto:
2678         proto_unregister(&pppol2tp_sk_proto);
2679         goto out;
2680 }
2681
2682 static void __exit pppol2tp_exit(void)
2683 {
2684         unregister_pppox_proto(PX_PROTO_OL2TP);
2685         proto_unregister(&pppol2tp_sk_proto);
2686 }
2687
2688 module_init(pppol2tp_init);
2689 module_exit(pppol2tp_exit);
2690
2691 MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, "
2692               "James Chapman <jchapman@katalix.com>");
2693 MODULE_DESCRIPTION("PPP over L2TP over UDP");
2694 MODULE_LICENSE("GPL");
2695 MODULE_VERSION(PPPOL2TP_DRV_VERSION);