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