drivers/net/pppol2tp.c

   1 /*****************************************************************************
   2  * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
   3  *
   4  * PPPoX    --- Generic PPP encapsulation socket family
   5  * PPPoL2TP --- PPP over L2TP (RFC 2661)
   6  *
   7  * Version:     1.0.0
   8  *
   9  * Authors:     Martijn van Oosterhout <kleptog@svana.org>
  10  *              James Chapman (jchapman@katalix.com)
  11  * Contributors:
  12  *              Michal Ostrowski <mostrows@speakeasy.net>
  13  *              Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
  14  *              David S. Miller (davem@redhat.com)
  15  *
  16  * License:
  17  *              This program is free software; you can redistribute it and/or
  18  *              modify it under the terms of the GNU General Public License
  19  *              as published by the Free Software Foundation; either version
  20  *              2 of the License, or (at your option) any later version.
  21  *
  22  */
  23
  24 /* This driver handles only L2TP data frames; control frames are handled by a
  25  * userspace application.
  26  *
  27  * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
  28  * attaches it to a bound UDP socket with local tunnel_id / session_id and
  29  * peer tunnel_id / session_id set. Data can then be sent or received using
  30  * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
  31  * can be read or modified using ioctl() or [gs]etsockopt() calls.
  32  *
  33  * When a PPPoL2TP socket is connected with local and peer session_id values
  34  * zero, the socket is treated as a special tunnel management socket.
  35  *
  36  * Here's example userspace code to create a socket for sending/receiving data
  37  * over an L2TP session:-
  38  *
  39  *      struct sockaddr_pppol2tp sax;
  40  *      int fd;
  41  *      int session_fd;
  42  *
  43  *      fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
  44  *
  45  *      sax.sa_family = AF_PPPOX;
  46  *      sax.sa_protocol = PX_PROTO_OL2TP;
  47  *      sax.pppol2tp.fd = tunnel_fd;    // bound UDP socket
  48  *      sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
  49  *      sax.pppol2tp.addr.sin_port = addr->sin_port;
  50  *      sax.pppol2tp.addr.sin_family = AF_INET;
  51  *      sax.pppol2tp.s_tunnel  = tunnel_id;
  52  *      sax.pppol2tp.s_session = session_id;
  53  *      sax.pppol2tp.d_tunnel  = peer_tunnel_id;
  54  *      sax.pppol2tp.d_session = peer_session_id;
  55  *
  56  *      session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
  57  *
  58  * A pppd plugin that allows PPP traffic to be carried over L2TP using
  59  * this driver is available from the OpenL2TP project at
  60  * http://openl2tp.sourceforge.net.
  61  */
  62
  63 #include <linux/module.h>
  64 #include <linux/string.h>
  65 #include <linux/list.h>
  66 #include <asm/uaccess.h>
  67
  68 #include <linux/kernel.h>
  69 #include <linux/spinlock.h>
  70 #include <linux/kthread.h>
  71 #include <linux/sched.h>
  72 #include <linux/slab.h>
  73 #include <linux/errno.h>
  74 #include <linux/jiffies.h>
  75
  76 #include <linux/netdevice.h>
  77 #include <linux/net.h>
  78 #include <linux/inetdevice.h>
  79 #include <linux/skbuff.h>
  80 #include <linux/init.h>
  81 #include <linux/ip.h>
  82 #include <linux/udp.h>
  83 #include <linux/if_pppox.h>
  84 #include <linux/if_pppol2tp.h>
  85 #include <net/sock.h>
  86 #include <linux/ppp_channel.h>
  87 #include <linux/ppp_defs.h>
  88 #include <linux/if_ppp.h>
  89 #include <linux/file.h>
  90 #include <linux/hash.h>
  91 #include <linux/sort.h>
  92 #include <linux/proc_fs.h>
  93 #include <net/net_namespace.h>
  94 #include <net/dst.h>
  95 #include <net/ip.h>
  96 #include <net/udp.h>
  97 #include <net/xfrm.h>
  98
  99 #include <asm/byteorder.h>
 100 #include <asm/atomic.h>
 101
 102
 103 #define PPPOL2TP_DRV_VERSION    "V1.0"
 104
 105 /* L2TP header constants */
 106 #define L2TP_HDRFLAG_T     0x8000
 107 #define L2TP_HDRFLAG_L     0x4000
 108 #define L2TP_HDRFLAG_S     0x0800
 109 #define L2TP_HDRFLAG_O     0x0200
 110 #define L2TP_HDRFLAG_P     0x0100
 111
 112 #define L2TP_HDR_VER_MASK  0x000F
 113 #define L2TP_HDR_VER       0x0002
 114
 115 /* Space for UDP, L2TP and PPP headers */
 116 #define PPPOL2TP_HEADER_OVERHEAD        40
 117
 118 /* Just some random numbers */
 119 #define L2TP_TUNNEL_MAGIC       0x42114DDA
 120 #define L2TP_SESSION_MAGIC      0x0C04EB7D
 121
 122 #define PPPOL2TP_HASH_BITS      4
 123 #define PPPOL2TP_HASH_SIZE      (1 << PPPOL2TP_HASH_BITS)
 124
 125 /* Default trace flags */
 126 #define PPPOL2TP_DEFAULT_DEBUG_FLAGS    0
 127
 128 #define PRINTK(_mask, _type, _lvl, _fmt, args...)                       \
 129         do {                                                            \
 130                 if ((_mask) & (_type))                                  \
 131                         printk(_lvl "PPPOL2TP: " _fmt, ##args);         \
 132         } while(0)
 133
 134 /* Number of bytes to build transmit L2TP headers.
 135  * Unfortunately the size is different depending on whether sequence numbers
 136  * are enabled.
 137  */
 138 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ              10
 139 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ            6
 140
 141 struct pppol2tp_tunnel;
 142
 143 /* Describes a session. It is the sk_user_data field in the PPPoL2TP
 144  * socket. Contains information to determine incoming packets and transmit
 145  * outgoing ones.
 146  */
 147 struct pppol2tp_session
 148 {
 149         int                     magic;          /* should be
 150                                                  * L2TP_SESSION_MAGIC */
 151         int                     owner;          /* pid that opened the socket */
 152
 153         struct sock             *sock;          /* Pointer to the session
 154                                                  * PPPoX socket */
 155         struct sock             *tunnel_sock;   /* Pointer to the tunnel UDP
 156                                                  * socket */
 157
 158         struct pppol2tp_addr    tunnel_addr;    /* Description of tunnel */
 159
 160         struct pppol2tp_tunnel  *tunnel;        /* back pointer to tunnel
 161                                                  * context */
 162
 163         char                    name[20];       /* "sess xxxxx/yyyyy", where
 164                                                  * x=tunnel_id, y=session_id */
 165         int                     mtu;
 166         int                     mru;
 167         int                     flags;          /* accessed by PPPIOCGFLAGS.
 168                                                  * Unused. */
 169         unsigned                recv_seq:1;     /* expect receive packets with
 170                                                  * sequence numbers? */
 171         unsigned                send_seq:1;     /* send packets with sequence
 172                                                  * numbers? */
 173         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
 174                                                  * sequence numbers under
 175                                                  * control of LNS. */
 176         int                     debug;          /* bitmask of debug message
 177                                                  * categories */
 178         int                     reorder_timeout; /* configured reorder timeout
 179                                                   * (in jiffies) */
 180         u16                     nr;             /* session NR state (receive) */
 181         u16                     ns;             /* session NR state (send) */
 182         struct sk_buff_head     reorder_q;      /* receive reorder queue */
 183         struct pppol2tp_ioc_stats stats;
 184         struct hlist_node       hlist;          /* Hash list node */
 185 };
 186
 187 /* The sk_user_data field of the tunnel's UDP socket. It contains info to track
 188  * all the associated sessions so incoming packets can be sorted out
 189  */
 190 struct pppol2tp_tunnel
 191 {
 192         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 193         rwlock_t                hlist_lock;     /* protect session_hlist */
 194         struct hlist_head       session_hlist[PPPOL2TP_HASH_SIZE];
 195                                                 /* hashed list of sessions,
 196                                                  * hashed by id */
 197         int                     debug;          /* bitmask of debug message
 198                                                  * categories */
 199         char                    name[12];       /* "tunl xxxxx" */
 200         struct pppol2tp_ioc_stats stats;
 201
 202         void (*old_sk_destruct)(struct sock *);
 203
 204         struct sock             *sock;          /* Parent socket */
 205         struct list_head        list;           /* Keep a list of all open
 206                                                  * prepared sockets */
 207
 208         atomic_t                ref_count;
 209 };
 210
 211 /* Private data stored for received packets in the skb.
 212  */
 213 struct pppol2tp_skb_cb {
 214         u16                     ns;
 215         u16                     nr;
 216         u16                     has_seq;
 217         u16                     length;
 218         unsigned long           expires;
 219 };
 220
 221 #define PPPOL2TP_SKB_CB(skb)    ((struct pppol2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
 222
 223 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
 224 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel);
 225
 226 static atomic_t pppol2tp_tunnel_count;
 227 static atomic_t pppol2tp_session_count;
 228 static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
 229 static struct proto_ops pppol2tp_ops;
 230 static LIST_HEAD(pppol2tp_tunnel_list);
 231 static DEFINE_RWLOCK(pppol2tp_tunnel_list_lock);
 232
 233 /* Helpers to obtain tunnel/session contexts from sockets.
 234  */
 235 static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk)
 236 {
 237         struct pppol2tp_session *session;
 238
 239         if (sk == NULL)
 240                 return NULL;
 241
 242         sock_hold(sk);
 243         session = (struct pppol2tp_session *)(sk->sk_user_data);
 244         if (session == NULL) {
 245                 sock_put(sk);
 246                 goto out;
 247         }
 248
 249         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 250 out:
 251         return session;
 252 }
 253
 254 static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk)
 255 {
 256         struct pppol2tp_tunnel *tunnel;
 257
 258         if (sk == NULL)
 259                 return NULL;
 260
 261         sock_hold(sk);
 262         tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data);
 263         if (tunnel == NULL) {
 264                 sock_put(sk);
 265                 goto out;
 266         }
 267
 268         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 269 out:
 270         return tunnel;
 271 }
 272
 273 /* Tunnel reference counts. Incremented per session that is added to
 274  * the tunnel.
 275  */
 276 static inline void pppol2tp_tunnel_inc_refcount(struct pppol2tp_tunnel *tunnel)
 277 {
 278         atomic_inc(&tunnel->ref_count);
 279 }
 280
 281 static inline void pppol2tp_tunnel_dec_refcount(struct pppol2tp_tunnel *tunnel)
 282 {
 283         if (atomic_dec_and_test(&tunnel->ref_count))
 284                 pppol2tp_tunnel_free(tunnel);
 285 }
 286
 287 /* Session hash list.
 288  * The session_id SHOULD be random according to RFC2661, but several
 289  * L2TP implementations (Cisco and Microsoft) use incrementing
 290  * session_ids.  So we do a real hash on the session_id, rather than a
 291  * simple bitmask.
 292  */
 293 static inline struct hlist_head *
 294 pppol2tp_session_id_hash(struct pppol2tp_tunnel *tunnel, u16 session_id)
 295 {
 296         unsigned long hash_val = (unsigned long) session_id;
 297         return &tunnel->session_hlist[hash_long(hash_val, PPPOL2TP_HASH_BITS)];
 298 }
 299
 300 /* Lookup a session by id
 301  */
 302 static struct pppol2tp_session *
 303 pppol2tp_session_find(struct pppol2tp_tunnel *tunnel, u16 session_id)
 304 {
 305         struct hlist_head *session_list =
 306                 pppol2tp_session_id_hash(tunnel, session_id);
 307         struct pppol2tp_session *session;
 308         struct hlist_node *walk;
 309
 310         read_lock_bh(&tunnel->hlist_lock);
 311         hlist_for_each_entry(session, walk, session_list, hlist) {
 312                 if (session->tunnel_addr.s_session == session_id) {
 313                         read_unlock_bh(&tunnel->hlist_lock);
 314                         return session;
 315                 }
 316         }
 317         read_unlock_bh(&tunnel->hlist_lock);
 318
 319         return NULL;
 320 }
 321
 322 /* Lookup a tunnel by id
 323  */
 324 static struct pppol2tp_tunnel *pppol2tp_tunnel_find(u16 tunnel_id)
 325 {
 326         struct pppol2tp_tunnel *tunnel = NULL;
 327
 328         read_lock_bh(&pppol2tp_tunnel_list_lock);
 329         list_for_each_entry(tunnel, &pppol2tp_tunnel_list, list) {
 330                 if (tunnel->stats.tunnel_id == tunnel_id) {
 331                         read_unlock_bh(&pppol2tp_tunnel_list_lock);
 332                         return tunnel;
 333                 }
 334         }
 335         read_unlock_bh(&pppol2tp_tunnel_list_lock);
 336
 337         return NULL;
 338 }
 339
 340 /*****************************************************************************
 341  * Receive data handling
 342  *****************************************************************************/
 343
 344 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
 345  * number.
 346  */
 347 static void pppol2tp_recv_queue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 348 {
 349         struct sk_buff *skbp;
 350         struct sk_buff *tmp;
 351         u16 ns = PPPOL2TP_SKB_CB(skb)->ns;
 352
 353         spin_lock_bh(&session->reorder_q.lock);
 354         skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
 355                 if (PPPOL2TP_SKB_CB(skbp)->ns > ns) {
 356                         __skb_queue_before(&session->reorder_q, skbp, skb);
 357                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 358                                "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
 359                                session->name, ns, PPPOL2TP_SKB_CB(skbp)->ns,
 360                                skb_queue_len(&session->reorder_q));
 361                         session->stats.rx_oos_packets++;
 362                         goto out;
 363                 }
 364         }
 365
 366         __skb_queue_tail(&session->reorder_q, skb);
 367
 368 out:
 369         spin_unlock_bh(&session->reorder_q.lock);
 370 }
 371
 372 /* Dequeue a single skb.
 373  */
 374 static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 375 {
 376         struct pppol2tp_tunnel *tunnel = session->tunnel;
 377         int length = PPPOL2TP_SKB_CB(skb)->length;
 378         struct sock *session_sock = NULL;
 379
 380         /* We're about to requeue the skb, so return resources
 381          * to its current owner (a socket receive buffer).
 382          */
 383         skb_orphan(skb);
 384
 385         tunnel->stats.rx_packets++;
 386         tunnel->stats.rx_bytes += length;
 387         session->stats.rx_packets++;
 388         session->stats.rx_bytes += length;
 389
 390         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 391                 /* Bump our Nr */
 392                 session->nr++;
 393                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 394                        "%s: updated nr to %hu\n", session->name, session->nr);
 395         }
 396
 397         /* If the socket is bound, send it in to PPP's input queue. Otherwise
 398          * queue it on the session socket.
 399          */
 400         session_sock = session->sock;
 401         if (session_sock->sk_state & PPPOX_BOUND) {
 402                 struct pppox_sock *po;
 403                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 404                        "%s: recv %d byte data frame, passing to ppp\n",
 405                        session->name, length);
 406
 407                 /* We need to forget all info related to the L2TP packet
 408                  * gathered in the skb as we are going to reuse the same
 409                  * skb for the inner packet.
 410                  * Namely we need to:
 411                  * - reset xfrm (IPSec) information as it applies to
 412                  *   the outer L2TP packet and not to the inner one
 413                  * - release the dst to force a route lookup on the inner
 414                  *   IP packet since skb->dst currently points to the dst
 415                  *   of the UDP tunnel
 416                  * - reset netfilter information as it doesn't apply
 417                  *   to the inner packet either
 418                  */
 419                 secpath_reset(skb);
 420                 dst_release(skb->dst);
 421                 skb->dst = NULL;
 422                 nf_reset(skb);
 423
 424                 po = pppox_sk(session_sock);
 425                 ppp_input(&po->chan, skb);
 426         } else {
 427                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 428                        "%s: socket not bound\n", session->name);
 429
 430                 /* Not bound. Nothing we can do, so discard. */
 431                 session->stats.rx_errors++;
 432                 kfree_skb(skb);
 433         }
 434
 435         sock_put(session->sock);
 436 }
 437
 438 /* Dequeue skbs from the session's reorder_q, subject to packet order.
 439  * Skbs that have been in the queue for too long are simply discarded.
 440  */
 441 static void pppol2tp_recv_dequeue(struct pppol2tp_session *session)
 442 {
 443         struct sk_buff *skb;
 444         struct sk_buff *tmp;
 445
 446         /* If the pkt at the head of the queue has the nr that we
 447          * expect to send up next, dequeue it and any other
 448          * in-sequence packets behind it.
 449          */
 450         spin_lock_bh(&session->reorder_q.lock);
 451         skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
 452                 if (time_after(jiffies, PPPOL2TP_SKB_CB(skb)->expires)) {
 453                         session->stats.rx_seq_discards++;
 454                         session->stats.rx_errors++;
 455                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 456                                "%s: oos pkt %hu len %d discarded (too old), "
 457                                "waiting for %hu, reorder_q_len=%d\n",
 458                                session->name, PPPOL2TP_SKB_CB(skb)->ns,
 459                                PPPOL2TP_SKB_CB(skb)->length, session->nr,
 460                                skb_queue_len(&session->reorder_q));
 461                         __skb_unlink(skb, &session->reorder_q);
 462                         kfree_skb(skb);
 463                         sock_put(session->sock);
 464                         continue;
 465                 }
 466
 467                 if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 468                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 469                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 470                                        "%s: holding oos pkt %hu len %d, "
 471                                        "waiting for %hu, reorder_q_len=%d\n",
 472                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 473                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 474                                        skb_queue_len(&session->reorder_q));
 475                                 goto out;
 476                         }
 477                 }
 478                 __skb_unlink(skb, &session->reorder_q);
 479
 480                 /* Process the skb. We release the queue lock while we
 481                  * do so to let other contexts process the queue.
 482                  */
 483                 spin_unlock_bh(&session->reorder_q.lock);
 484                 pppol2tp_recv_dequeue_skb(session, skb);
 485                 spin_lock_bh(&session->reorder_q.lock);
 486         }
 487
 488 out:
 489         spin_unlock_bh(&session->reorder_q.lock);
 490 }
 491
 492 static inline int pppol2tp_verify_udp_checksum(struct sock *sk,
 493                                                struct sk_buff *skb)
 494 {
 495         struct udphdr *uh = udp_hdr(skb);
 496         u16 ulen = ntohs(uh->len);
 497         struct inet_sock *inet;
 498         __wsum psum;
 499
 500         if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
 501                 return 0;
 502
 503         inet = inet_sk(sk);
 504         psum = csum_tcpudp_nofold(inet->saddr, inet->daddr, ulen,
 505                                   IPPROTO_UDP, 0);
 506
 507         if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
 508             !csum_fold(csum_add(psum, skb->csum)))
 509                 return 0;
 510
 511         skb->csum = psum;
 512
 513         return __skb_checksum_complete(skb);
 514 }
 515
 516 /* Internal receive frame. Do the real work of receiving an L2TP data frame
 517  * here. The skb is not on a list when we get here.
 518  * Returns 0 if the packet was a data packet and was successfully passed on.
 519  * Returns 1 if the packet was not a good data packet and could not be
 520  * forwarded.  All such packets are passed up to userspace to deal with.
 521  */
 522 static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
 523 {
 524         struct pppol2tp_session *session = NULL;
 525         struct pppol2tp_tunnel *tunnel;
 526         unsigned char *ptr, *optr;
 527         u16 hdrflags;
 528         u16 tunnel_id, session_id;
 529         int length;
 530         int offset;
 531
 532         tunnel = pppol2tp_sock_to_tunnel(sock);
 533         if (tunnel == NULL)
 534                 goto no_tunnel;
 535
 536         if (tunnel->sock && pppol2tp_verify_udp_checksum(tunnel->sock, skb))
 537                 goto discard_bad_csum;
 538
 539         /* UDP always verifies the packet length. */
 540         __skb_pull(skb, sizeof(struct udphdr));
 541
 542         /* Short packet? */
 543         if (!pskb_may_pull(skb, 12)) {
 544                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 545                        "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
 546                 goto error;
 547         }
 548
 549         /* Point to L2TP header */
 550         optr = ptr = skb->data;
 551
 552         /* Get L2TP header flags */
 553         hdrflags = ntohs(*(__be16*)ptr);
 554
 555         /* Trace packet contents, if enabled */
 556         if (tunnel->debug & PPPOL2TP_MSG_DATA) {
 557                 length = min(16u, skb->len);
 558                 if (!pskb_may_pull(skb, length))
 559                         goto error;
 560
 561                 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
 562
 563                 offset = 0;
 564                 do {
 565                         printk(" %02X", ptr[offset]);
 566                 } while (++offset < length);
 567
 568                 printk("\n");
 569         }
 570
 571         /* Get length of L2TP packet */
 572         length = skb->len;
 573
 574         /* If type is control packet, it is handled by userspace. */
 575         if (hdrflags & L2TP_HDRFLAG_T) {
 576                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 577                        "%s: recv control packet, len=%d\n", tunnel->name, length);
 578                 goto error;
 579         }
 580
 581         /* Skip flags */
 582         ptr += 2;
 583
 584         /* If length is present, skip it */
 585         if (hdrflags & L2TP_HDRFLAG_L)
 586                 ptr += 2;
 587
 588         /* Extract tunnel and session ID */
 589         tunnel_id = ntohs(*(__be16 *) ptr);
 590         ptr += 2;
 591         session_id = ntohs(*(__be16 *) ptr);
 592         ptr += 2;
 593
 594         /* Find the session context */
 595         session = pppol2tp_session_find(tunnel, session_id);
 596         if (!session) {
 597                 /* Not found? Pass to userspace to deal with */
 598                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 599                        "%s: no socket found (%hu/%hu). Passing up.\n",
 600                        tunnel->name, tunnel_id, session_id);
 601                 goto error;
 602         }
 603         sock_hold(session->sock);
 604
 605         /* The ref count on the socket was increased by the above call since
 606          * we now hold a pointer to the session. Take care to do sock_put()
 607          * when exiting this function from now on...
 608          */
 609
 610         /* Handle the optional sequence numbers.  If we are the LAC,
 611          * enable/disable sequence numbers under the control of the LNS.  If
 612          * no sequence numbers present but we were expecting them, discard
 613          * frame.
 614          */
 615         if (hdrflags & L2TP_HDRFLAG_S) {
 616                 u16 ns, nr;
 617                 ns = ntohs(*(__be16 *) ptr);
 618                 ptr += 2;
 619                 nr = ntohs(*(__be16 *) ptr);
 620                 ptr += 2;
 621
 622                 /* Received a packet with sequence numbers. If we're the LNS,
 623                  * check if we sre sending sequence numbers and if not,
 624                  * configure it so.
 625                  */
 626                 if ((!session->lns_mode) && (!session->send_seq)) {
 627                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 628                                "%s: requested to enable seq numbers by LNS\n",
 629                                session->name);
 630                         session->send_seq = -1;
 631                 }
 632
 633                 /* Store L2TP info in the skb */
 634                 PPPOL2TP_SKB_CB(skb)->ns = ns;
 635                 PPPOL2TP_SKB_CB(skb)->nr = nr;
 636                 PPPOL2TP_SKB_CB(skb)->has_seq = 1;
 637
 638                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 639                        "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n",
 640                        session->name, ns, nr, session->nr);
 641         } else {
 642                 /* No sequence numbers.
 643                  * If user has configured mandatory sequence numbers, discard.
 644                  */
 645                 if (session->recv_seq) {
 646                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 647                                "%s: recv data has no seq numbers when required. "
 648                                "Discarding\n", session->name);
 649                         session->stats.rx_seq_discards++;
 650                         goto discard;
 651                 }
 652
 653                 /* If we're the LAC and we're sending sequence numbers, the
 654                  * LNS has requested that we no longer send sequence numbers.
 655                  * If we're the LNS and we're sending sequence numbers, the
 656                  * LAC is broken. Discard the frame.
 657                  */
 658                 if ((!session->lns_mode) && (session->send_seq)) {
 659                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 660                                "%s: requested to disable seq numbers by LNS\n",
 661                                session->name);
 662                         session->send_seq = 0;
 663                 } else if (session->send_seq) {
 664                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 665                                "%s: recv data has no seq numbers when required. "
 666                                "Discarding\n", session->name);
 667                         session->stats.rx_seq_discards++;
 668                         goto discard;
 669                 }
 670
 671                 /* Store L2TP info in the skb */
 672                 PPPOL2TP_SKB_CB(skb)->has_seq = 0;
 673         }
 674
 675         /* If offset bit set, skip it. */
 676         if (hdrflags & L2TP_HDRFLAG_O) {
 677                 offset = ntohs(*(__be16 *)ptr);
 678                 ptr += 2 + offset;
 679         }
 680
 681         offset = ptr - optr;
 682         if (!pskb_may_pull(skb, offset))
 683                 goto discard;
 684
 685         __skb_pull(skb, offset);
 686
 687         /* Skip PPP header, if present.  In testing, Microsoft L2TP clients
 688          * don't send the PPP header (PPP header compression enabled), but
 689          * other clients can include the header. So we cope with both cases
 690          * here. The PPP header is always FF03 when using L2TP.
 691          *
 692          * Note that skb->data[] isn't dereferenced from a u16 ptr here since
 693          * the field may be unaligned.
 694          */
 695         if (!pskb_may_pull(skb, 2))
 696                 goto discard;
 697
 698         if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
 699                 skb_pull(skb, 2);
 700
 701         /* Prepare skb for adding to the session's reorder_q.  Hold
 702          * packets for max reorder_timeout or 1 second if not
 703          * reordering.
 704          */
 705         PPPOL2TP_SKB_CB(skb)->length = length;
 706         PPPOL2TP_SKB_CB(skb)->expires = jiffies +
 707                 (session->reorder_timeout ? session->reorder_timeout : HZ);
 708
 709         /* Add packet to the session's receive queue. Reordering is done here, if
 710          * enabled. Saved L2TP protocol info is stored in skb->sb[].
 711          */
 712         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 713                 if (session->reorder_timeout != 0) {
 714                         /* Packet reordering enabled. Add skb to session's
 715                          * reorder queue, in order of ns.
 716                          */
 717                         pppol2tp_recv_queue_skb(session, skb);
 718                 } else {
 719                         /* Packet reordering disabled. Discard out-of-sequence
 720                          * packets
 721                          */
 722                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 723                                 session->stats.rx_seq_discards++;
 724                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 725                                        "%s: oos pkt %hu len %d discarded, "
 726                                        "waiting for %hu, reorder_q_len=%d\n",
 727                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 728                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 729                                        skb_queue_len(&session->reorder_q));
 730                                 goto discard;
 731                         }
 732                         skb_queue_tail(&session->reorder_q, skb);
 733                 }
 734         } else {
 735                 /* No sequence numbers. Add the skb to the tail of the
 736                  * reorder queue. This ensures that it will be
 737                  * delivered after all previous sequenced skbs.
 738                  */
 739                 skb_queue_tail(&session->reorder_q, skb);
 740         }
 741
 742         /* Try to dequeue as many skbs from reorder_q as we can. */
 743         pppol2tp_recv_dequeue(session);
 744
 745         return 0;
 746
 747 discard:
 748         session->stats.rx_errors++;
 749         kfree_skb(skb);
 750         sock_put(session->sock);
 751         sock_put(sock);
 752
 753         return 0;
 754
 755 discard_bad_csum:
 756         LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
 757         UDP_INC_STATS_USER(&init_net, UDP_MIB_INERRORS, 0);
 758         tunnel->stats.rx_errors++;
 759         kfree_skb(skb);
 760
 761         return 0;
 762
 763 error:
 764         /* Put UDP header back */
 765         __skb_push(skb, sizeof(struct udphdr));
 766         sock_put(sock);
 767
 768 no_tunnel:
 769         return 1;
 770 }
 771
 772 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
 773  * Return codes:
 774  * 0 : success.
 775  * <0: error
 776  * >0: skb should be passed up to userspace as UDP.
 777  */
 778 static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 779 {
 780         struct pppol2tp_tunnel *tunnel;
 781
 782         tunnel = pppol2tp_sock_to_tunnel(sk);
 783         if (tunnel == NULL)
 784                 goto pass_up;
 785
 786         PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 787                "%s: received %d bytes\n", tunnel->name, skb->len);
 788
 789         if (pppol2tp_recv_core(sk, skb))
 790                 goto pass_up_put;
 791
 792         sock_put(sk);
 793         return 0;
 794
 795 pass_up_put:
 796         sock_put(sk);
 797 pass_up:
 798         return 1;
 799 }
 800
 801 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
 802  */
 803 static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
 804                             struct msghdr *msg, size_t len,
 805                             int flags)
 806 {
 807         int err;
 808         struct sk_buff *skb;
 809         struct sock *sk = sock->sk;
 810
 811         err = -EIO;
 812         if (sk->sk_state & PPPOX_BOUND)
 813                 goto end;
 814
 815         msg->msg_namelen = 0;
 816
 817         err = 0;
 818         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 819                                 flags & MSG_DONTWAIT, &err);
 820         if (!skb)
 821                 goto end;
 822
 823         if (len > skb->len)
 824                 len = skb->len;
 825         else if (len < skb->len)
 826                 msg->msg_flags |= MSG_TRUNC;
 827
 828         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
 829         if (likely(err == 0))
 830                 err = len;
 831
 832         kfree_skb(skb);
 833 end:
 834         return err;
 835 }
 836
 837 /************************************************************************
 838  * Transmit handling
 839  ***********************************************************************/
 840
 841 /* Tell how big L2TP headers are for a particular session. This
 842  * depends on whether sequence numbers are being used.
 843  */
 844 static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session)
 845 {
 846         if (session->send_seq)
 847                 return PPPOL2TP_L2TP_HDR_SIZE_SEQ;
 848
 849         return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
 850 }
 851
 852 /* Build an L2TP header for the session into the buffer provided.
 853  */
 854 static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session,
 855                                        void *buf)
 856 {
 857         __be16 *bufp = buf;
 858         u16 flags = L2TP_HDR_VER;
 859
 860         if (session->send_seq)
 861                 flags |= L2TP_HDRFLAG_S;
 862
 863         /* Setup L2TP header.
 864          * FIXME: Can this ever be unaligned? Is direct dereferencing of
 865          * 16-bit header fields safe here for all architectures?
 866          */
 867         *bufp++ = htons(flags);
 868         *bufp++ = htons(session->tunnel_addr.d_tunnel);
 869         *bufp++ = htons(session->tunnel_addr.d_session);
 870         if (session->send_seq) {
 871                 *bufp++ = htons(session->ns);
 872                 *bufp++ = 0;
 873                 session->ns++;
 874                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 875                        "%s: updated ns to %hu\n", session->name, session->ns);
 876         }
 877 }
 878
 879 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
 880  * when a user application does a sendmsg() on the session socket. L2TP and
 881  * PPP headers must be inserted into the user's data.
 882  */
 883 static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
 884                             size_t total_len)
 885 {
 886         static const unsigned char ppph[2] = { 0xff, 0x03 };
 887         struct sock *sk = sock->sk;
 888         struct inet_sock *inet;
 889         __wsum csum;
 890         struct sk_buff *skb;
 891         int error;
 892         int hdr_len;
 893         struct pppol2tp_session *session;
 894         struct pppol2tp_tunnel *tunnel;
 895         struct udphdr *uh;
 896         unsigned int len;
 897         struct sock *sk_tun;
 898         u16 udp_len;
 899
 900         error = -ENOTCONN;
 901         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 902                 goto error;
 903
 904         /* Get session and tunnel contexts */
 905         error = -EBADF;
 906         session = pppol2tp_sock_to_session(sk);
 907         if (session == NULL)
 908                 goto error;
 909
 910         sk_tun = session->tunnel_sock;
 911         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
 912         if (tunnel == NULL)
 913                 goto error_put_sess;
 914
 915         /* What header length is configured for this session? */
 916         hdr_len = pppol2tp_l2tp_header_len(session);
 917
 918         /* Allocate a socket buffer */
 919         error = -ENOMEM;
 920         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
 921                            sizeof(struct udphdr) + hdr_len +
 922                            sizeof(ppph) + total_len,
 923                            0, GFP_KERNEL);
 924         if (!skb)
 925                 goto error_put_sess_tun;
 926
 927         /* Reserve space for headers. */
 928         skb_reserve(skb, NET_SKB_PAD);
 929         skb_reset_network_header(skb);
 930         skb_reserve(skb, sizeof(struct iphdr));
 931         skb_reset_transport_header(skb);
 932
 933         /* Build UDP header */
 934         inet = inet_sk(sk_tun);
 935         udp_len = hdr_len + sizeof(ppph) + total_len;
 936         uh = (struct udphdr *) skb->data;
 937         uh->source = inet->sport;
 938         uh->dest = inet->dport;
 939         uh->len = htons(udp_len);
 940         uh->check = 0;
 941         skb_put(skb, sizeof(struct udphdr));
 942
 943         /* Build L2TP header */
 944         pppol2tp_build_l2tp_header(session, skb->data);
 945         skb_put(skb, hdr_len);
 946
 947         /* Add PPP header */
 948         skb->data[0] = ppph[0];
 949         skb->data[1] = ppph[1];
 950         skb_put(skb, 2);
 951
 952         /* Copy user data into skb */
 953         error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
 954         if (error < 0) {
 955                 kfree_skb(skb);
 956                 goto error_put_sess_tun;
 957         }
 958         skb_put(skb, total_len);
 959
 960         /* Calculate UDP checksum if configured to do so */
 961         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
 962                 skb->ip_summed = CHECKSUM_NONE;
 963         else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
 964                 skb->ip_summed = CHECKSUM_COMPLETE;
 965                 csum = skb_checksum(skb, 0, udp_len, 0);
 966                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
 967                                               udp_len, IPPROTO_UDP, csum);
 968                 if (uh->check == 0)
 969                         uh->check = CSUM_MANGLED_0;
 970         } else {
 971                 skb->ip_summed = CHECKSUM_PARTIAL;
 972                 skb->csum_start = skb_transport_header(skb) - skb->head;
 973                 skb->csum_offset = offsetof(struct udphdr, check);
 974                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
 975                                                udp_len, IPPROTO_UDP, 0);
 976         }
 977
 978         /* Debug */
 979         if (session->send_seq)
 980                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 981                        "%s: send %Zd bytes, ns=%hu\n", session->name,
 982                        total_len, session->ns - 1);
 983         else
 984                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 985                        "%s: send %Zd bytes\n", session->name, total_len);
 986
 987         if (session->debug & PPPOL2TP_MSG_DATA) {
 988                 int i;
 989                 unsigned char *datap = skb->data;
 990
 991                 printk(KERN_DEBUG "%s: xmit:", session->name);
 992                 for (i = 0; i < total_len; i++) {
 993                         printk(" %02X", *datap++);
 994                         if (i == 15) {
 995                                 printk(" ...");
 996                                 break;
 997                         }
 998                 }
 999                 printk("\n");
1000         }
1001
1002         /* Queue the packet to IP for output */
1003         len = skb->len;
1004         error = ip_queue_xmit(skb, 1);
1005
1006         /* Update stats */
1007         if (error >= 0) {
1008                 tunnel->stats.tx_packets++;
1009                 tunnel->stats.tx_bytes += len;
1010                 session->stats.tx_packets++;
1011                 session->stats.tx_bytes += len;
1012         } else {
1013                 tunnel->stats.tx_errors++;
1014                 session->stats.tx_errors++;
1015         }
1016
1017         return error;
1018
1019 error_put_sess_tun:
1020         sock_put(session->tunnel_sock);
1021 error_put_sess:
1022         sock_put(sk);
1023 error:
1024         return error;
1025 }
1026
1027 /* Automatically called when the skb is freed.
1028  */
1029 static void pppol2tp_sock_wfree(struct sk_buff *skb)
1030 {
1031         sock_put(skb->sk);
1032 }
1033
1034 /* For data skbs that we transmit, we associate with the tunnel socket
1035  * but don't do accounting.
1036  */
1037 static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1038 {
1039         sock_hold(sk);
1040         skb->sk = sk;
1041         skb->destructor = pppol2tp_sock_wfree;
1042 }
1043
1044 /* Transmit function called by generic PPP driver.  Sends PPP frame
1045  * over PPPoL2TP socket.
1046  *
1047  * This is almost the same as pppol2tp_sendmsg(), but rather than
1048  * being called with a msghdr from userspace, it is called with a skb
1049  * from the kernel.
1050  *
1051  * The supplied skb from ppp doesn't have enough headroom for the
1052  * insertion of L2TP, UDP and IP headers so we need to allocate more
1053  * headroom in the skb. This will create a cloned skb. But we must be
1054  * careful in the error case because the caller will expect to free
1055  * the skb it supplied, not our cloned skb. So we take care to always
1056  * leave the original skb unfreed if we return an error.
1057  */
1058 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
1059 {
1060         static const u8 ppph[2] = { 0xff, 0x03 };
1061         struct sock *sk = (struct sock *) chan->private;
1062         struct sock *sk_tun;
1063         int hdr_len;
1064         u16 udp_len;
1065         struct pppol2tp_session *session;
1066         struct pppol2tp_tunnel *tunnel;
1067         int rc;
1068         int headroom;
1069         int data_len = skb->len;
1070         struct inet_sock *inet;
1071         __wsum csum;
1072         struct udphdr *uh;
1073         unsigned int len;
1074         int old_headroom;
1075         int new_headroom;
1076
1077         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
1078                 goto abort;
1079
1080         /* Get session and tunnel contexts from the socket */
1081         session = pppol2tp_sock_to_session(sk);
1082         if (session == NULL)
1083                 goto abort;
1084
1085         sk_tun = session->tunnel_sock;
1086         if (sk_tun == NULL)
1087                 goto abort_put_sess;
1088         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
1089         if (tunnel == NULL)
1090                 goto abort_put_sess;
1091
1092         /* What header length is configured for this session? */
1093         hdr_len = pppol2tp_l2tp_header_len(session);
1094
1095         /* Check that there's enough headroom in the skb to insert IP,
1096          * UDP and L2TP and PPP headers. If not enough, expand it to
1097          * make room. Adjust truesize.
1098          */
1099         headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1100                 sizeof(struct udphdr) + hdr_len + sizeof(ppph);
1101         old_headroom = skb_headroom(skb);
1102         if (skb_cow_head(skb, headroom))
1103                 goto abort_put_sess_tun;
1104
1105         new_headroom = skb_headroom(skb);
1106         skb_orphan(skb);
1107         skb->truesize += new_headroom - old_headroom;
1108
1109         /* Setup PPP header */
1110         __skb_push(skb, sizeof(ppph));
1111         skb->data[0] = ppph[0];
1112         skb->data[1] = ppph[1];
1113
1114         /* Setup L2TP header */
1115         pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
1116
1117         udp_len = sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len;
1118
1119         /* Setup UDP header */
1120         inet = inet_sk(sk_tun);
1121         __skb_push(skb, sizeof(*uh));
1122         skb_reset_transport_header(skb);
1123         uh = udp_hdr(skb);
1124         uh->source = inet->sport;
1125         uh->dest = inet->dport;
1126         uh->len = htons(udp_len);
1127         uh->check = 0;
1128
1129         /* Debug */
1130         if (session->send_seq)
1131                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1132                        "%s: send %d bytes, ns=%hu\n", session->name,
1133                        data_len, session->ns - 1);
1134         else
1135                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1136                        "%s: send %d bytes\n", session->name, data_len);
1137
1138         if (session->debug & PPPOL2TP_MSG_DATA) {
1139                 int i;
1140                 unsigned char *datap = skb->data;
1141
1142                 printk(KERN_DEBUG "%s: xmit:", session->name);
1143                 for (i = 0; i < data_len; i++) {
1144                         printk(" %02X", *datap++);
1145                         if (i == 31) {
1146                                 printk(" ...");
1147                                 break;
1148                         }
1149                 }
1150                 printk("\n");
1151         }
1152
1153         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1154         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1155                               IPSKB_REROUTED);
1156         nf_reset(skb);
1157
1158         /* Get routing info from the tunnel socket */
1159         dst_release(skb->dst);
1160         skb->dst = dst_clone(__sk_dst_get(sk_tun));
1161         pppol2tp_skb_set_owner_w(skb, sk_tun);
1162
1163         /* Calculate UDP checksum if configured to do so */
1164         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
1165                 skb->ip_summed = CHECKSUM_NONE;
1166         else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
1167                 skb->ip_summed = CHECKSUM_COMPLETE;
1168                 csum = skb_checksum(skb, 0, udp_len, 0);
1169                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
1170                                               udp_len, IPPROTO_UDP, csum);
1171                 if (uh->check == 0)
1172                         uh->check = CSUM_MANGLED_0;
1173         } else {
1174                 skb->ip_summed = CHECKSUM_PARTIAL;
1175                 skb->csum_start = skb_transport_header(skb) - skb->head;
1176                 skb->csum_offset = offsetof(struct udphdr, check);
1177                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
1178                                                udp_len, IPPROTO_UDP, 0);
1179         }
1180
1181         /* Queue the packet to IP for output */
1182         len = skb->len;
1183         rc = ip_queue_xmit(skb, 1);
1184
1185         /* Update stats */
1186         if (rc >= 0) {
1187                 tunnel->stats.tx_packets++;
1188                 tunnel->stats.tx_bytes += len;
1189                 session->stats.tx_packets++;
1190                 session->stats.tx_bytes += len;
1191         } else {
1192                 tunnel->stats.tx_errors++;
1193                 session->stats.tx_errors++;
1194         }
1195
1196         sock_put(sk_tun);
1197         sock_put(sk);
1198         return 1;
1199
1200 abort_put_sess_tun:
1201         sock_put(sk_tun);
1202 abort_put_sess:
1203         sock_put(sk);
1204 abort:
1205         /* Free the original skb */
1206         kfree_skb(skb);
1207         return 1;
1208 }
1209
1210 /*****************************************************************************
1211  * Session (and tunnel control) socket create/destroy.
1212  *****************************************************************************/
1213
1214 /* When the tunnel UDP socket is closed, all the attached sockets need to go
1215  * too.
1216  */
1217 static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel)
1218 {
1219         int hash;
1220         struct hlist_node *walk;
1221         struct hlist_node *tmp;
1222         struct pppol2tp_session *session;
1223         struct sock *sk;
1224
1225         if (tunnel == NULL)
1226                 BUG();
1227
1228         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1229                "%s: closing all sessions...\n", tunnel->name);
1230
1231         write_lock_bh(&tunnel->hlist_lock);
1232         for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) {
1233 again:
1234                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1235                         struct sk_buff *skb;
1236
1237                         session = hlist_entry(walk, struct pppol2tp_session, hlist);
1238
1239                         sk = session->sock;
1240
1241                         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1242                                "%s: closing session\n", session->name);
1243
1244                         hlist_del_init(&session->hlist);
1245
1246                         /* Since we should hold the sock lock while
1247                          * doing any unbinding, we need to release the
1248                          * lock we're holding before taking that lock.
1249                          * Hold a reference to the sock so it doesn't
1250                          * disappear as we're jumping between locks.
1251                          */
1252                         sock_hold(sk);
1253                         write_unlock_bh(&tunnel->hlist_lock);
1254                         lock_sock(sk);
1255
1256                         if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
1257                                 pppox_unbind_sock(sk);
1258                                 sk->sk_state = PPPOX_DEAD;
1259                                 sk->sk_state_change(sk);
1260                         }
1261
1262                         /* Purge any queued data */
1263                         skb_queue_purge(&sk->sk_receive_queue);
1264                         skb_queue_purge(&sk->sk_write_queue);
1265                         while ((skb = skb_dequeue(&session->reorder_q))) {
1266                                 kfree_skb(skb);
1267                                 sock_put(sk);
1268                         }
1269
1270                         release_sock(sk);
1271                         sock_put(sk);
1272
1273                         /* Now restart from the beginning of this hash
1274                          * chain.  We always remove a session from the
1275                          * list so we are guaranteed to make forward
1276                          * progress.
1277                          */
1278                         write_lock_bh(&tunnel->hlist_lock);
1279                         goto again;
1280                 }
1281         }
1282         write_unlock_bh(&tunnel->hlist_lock);
1283 }
1284
1285 /* Really kill the tunnel.
1286  * Come here only when all sessions have been cleared from the tunnel.
1287  */
1288 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
1289 {
1290         /* Remove from socket list */
1291         write_lock_bh(&pppol2tp_tunnel_list_lock);
1292         list_del_init(&tunnel->list);
1293         write_unlock_bh(&pppol2tp_tunnel_list_lock);
1294
1295         atomic_dec(&pppol2tp_tunnel_count);
1296         kfree(tunnel);
1297 }
1298
1299 /* Tunnel UDP socket destruct hook.
1300  * The tunnel context is deleted only when all session sockets have been
1301  * closed.
1302  */
1303 static void pppol2tp_tunnel_destruct(struct sock *sk)
1304 {
1305         struct pppol2tp_tunnel *tunnel;
1306
1307         tunnel = sk->sk_user_data;
1308         if (tunnel == NULL)
1309                 goto end;
1310
1311         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1312                "%s: closing...\n", tunnel->name);
1313
1314         /* Close all sessions */
1315         pppol2tp_tunnel_closeall(tunnel);
1316
1317         /* No longer an encapsulation socket. See net/ipv4/udp.c */
1318         (udp_sk(sk))->encap_type = 0;
1319         (udp_sk(sk))->encap_rcv = NULL;
1320
1321         /* Remove hooks into tunnel socket */
1322         tunnel->sock = NULL;
1323         sk->sk_destruct = tunnel->old_sk_destruct;
1324         sk->sk_user_data = NULL;
1325
1326         /* Call original (UDP) socket descructor */
1327         if (sk->sk_destruct != NULL)
1328                 (*sk->sk_destruct)(sk);
1329
1330         pppol2tp_tunnel_dec_refcount(tunnel);
1331
1332 end:
1333         return;
1334 }
1335
1336 /* Really kill the session socket. (Called from sock_put() if
1337  * refcnt == 0.)
1338  */
1339 static void pppol2tp_session_destruct(struct sock *sk)
1340 {
1341         struct pppol2tp_session *session = NULL;
1342
1343         if (sk->sk_user_data != NULL) {
1344                 struct pppol2tp_tunnel *tunnel;
1345
1346                 session = sk->sk_user_data;
1347                 if (session == NULL)
1348                         goto out;
1349
1350                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
1351
1352                 /* Don't use pppol2tp_sock_to_tunnel() here to
1353                  * get the tunnel context because the tunnel
1354                  * socket might have already been closed (its
1355                  * sk->sk_user_data will be NULL) so use the
1356                  * session's private tunnel ptr instead.
1357                  */
1358                 tunnel = session->tunnel;
1359                 if (tunnel != NULL) {
1360                         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1361
1362                         /* If session_id is zero, this is a null
1363                          * session context, which was created for a
1364                          * socket that is being used only to manage
1365                          * tunnels.
1366                          */
1367                         if (session->tunnel_addr.s_session != 0) {
1368                                 /* Delete the session socket from the
1369                                  * hash
1370                                  */
1371                                 write_lock_bh(&tunnel->hlist_lock);
1372                                 hlist_del_init(&session->hlist);
1373                                 write_unlock_bh(&tunnel->hlist_lock);
1374
1375                                 atomic_dec(&pppol2tp_session_count);
1376                         }
1377
1378                         /* This will delete the tunnel context if this
1379                          * is the last session on the tunnel.
1380                          */
1381                         session->tunnel = NULL;
1382                         session->tunnel_sock = NULL;
1383                         pppol2tp_tunnel_dec_refcount(tunnel);
1384                 }
1385         }
1386
1387         kfree(session);
1388 out:
1389         return;
1390 }
1391
1392 /* Called when the PPPoX socket (session) is closed.
1393  */
1394 static int pppol2tp_release(struct socket *sock)
1395 {
1396         struct sock *sk = sock->sk;
1397         struct pppol2tp_session *session;
1398         int error;
1399
1400         if (!sk)
1401                 return 0;
1402
1403         error = -EBADF;
1404         lock_sock(sk);
1405         if (sock_flag(sk, SOCK_DEAD) != 0)
1406                 goto error;
1407
1408         pppox_unbind_sock(sk);
1409
1410         /* Signal the death of the socket. */
1411         sk->sk_state = PPPOX_DEAD;
1412         sock_orphan(sk);
1413         sock->sk = NULL;
1414
1415         session = pppol2tp_sock_to_session(sk);
1416
1417         /* Purge any queued data */
1418         skb_queue_purge(&sk->sk_receive_queue);
1419         skb_queue_purge(&sk->sk_write_queue);
1420         if (session != NULL) {
1421                 struct sk_buff *skb;
1422                 while ((skb = skb_dequeue(&session->reorder_q))) {
1423                         kfree_skb(skb);
1424                         sock_put(sk);
1425                 }
1426                 sock_put(sk);
1427         }
1428
1429         release_sock(sk);
1430
1431         /* This will delete the session context via
1432          * pppol2tp_session_destruct() if the socket's refcnt drops to
1433          * zero.
1434          */
1435         sock_put(sk);
1436
1437         return 0;
1438
1439 error:
1440         release_sock(sk);
1441         return error;
1442 }
1443
1444 /* Internal function to prepare a tunnel (UDP) socket to have PPPoX
1445  * sockets attached to it.
1446  */
1447 static struct sock *pppol2tp_prepare_tunnel_socket(int fd, u16 tunnel_id,
1448                                                    int *error)
1449 {
1450         int err;
1451         struct socket *sock = NULL;
1452         struct sock *sk;
1453         struct pppol2tp_tunnel *tunnel;
1454         struct sock *ret = NULL;
1455
1456         /* Get the tunnel UDP socket from the fd, which was opened by
1457          * the userspace L2TP daemon.
1458          */
1459         err = -EBADF;
1460         sock = sockfd_lookup(fd, &err);
1461         if (!sock) {
1462                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1463                        "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1464                        tunnel_id, fd, err);
1465                 goto err;
1466         }
1467
1468         sk = sock->sk;
1469
1470         /* Quick sanity checks */
1471         err = -EPROTONOSUPPORT;
1472         if (sk->sk_protocol != IPPROTO_UDP) {
1473                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1474                        "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1475                        tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1476                 goto err;
1477         }
1478         err = -EAFNOSUPPORT;
1479         if (sock->ops->family != AF_INET) {
1480                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1481                        "tunl %hu: fd %d wrong family, got %d, expected %d\n",
1482                        tunnel_id, fd, sock->ops->family, AF_INET);
1483                 goto err;
1484         }
1485
1486         err = -ENOTCONN;
1487
1488         /* Check if this socket has already been prepped */
1489         tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;
1490         if (tunnel != NULL) {
1491                 /* User-data field already set */
1492                 err = -EBUSY;
1493                 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1494
1495                 /* This socket has already been prepped */
1496                 ret = tunnel->sock;
1497                 goto out;
1498         }
1499
1500         /* This socket is available and needs prepping. Create a new tunnel
1501          * context and init it.
1502          */
1503         sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL);
1504         if (sk->sk_user_data == NULL) {
1505                 err = -ENOMEM;
1506                 goto err;
1507         }
1508
1509         tunnel->magic = L2TP_TUNNEL_MAGIC;
1510         sprintf(&tunnel->name[0], "tunl %hu", tunnel_id);
1511
1512         tunnel->stats.tunnel_id = tunnel_id;
1513         tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS;
1514
1515         /* Hook on the tunnel socket destructor so that we can cleanup
1516          * if the tunnel socket goes away.
1517          */
1518         tunnel->old_sk_destruct = sk->sk_destruct;
1519         sk->sk_destruct = &pppol2tp_tunnel_destruct;
1520
1521         tunnel->sock = sk;
1522         sk->sk_allocation = GFP_ATOMIC;
1523
1524         /* Misc init */
1525         rwlock_init(&tunnel->hlist_lock);
1526
1527         /* Add tunnel to our list */
1528         INIT_LIST_HEAD(&tunnel->list);
1529         write_lock_bh(&pppol2tp_tunnel_list_lock);
1530         list_add(&tunnel->list, &pppol2tp_tunnel_list);
1531         write_unlock_bh(&pppol2tp_tunnel_list_lock);
1532         atomic_inc(&pppol2tp_tunnel_count);
1533
1534         /* Bump the reference count. The tunnel context is deleted
1535          * only when this drops to zero.
1536          */
1537         pppol2tp_tunnel_inc_refcount(tunnel);
1538
1539         /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1540         (udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP;
1541         (udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv;
1542
1543         ret = tunnel->sock;
1544
1545         *error = 0;
1546 out:
1547         if (sock)
1548                 sockfd_put(sock);
1549
1550         return ret;
1551
1552 err:
1553         *error = err;
1554         goto out;
1555 }
1556
1557 static struct proto pppol2tp_sk_proto = {
1558         .name     = "PPPOL2TP",
1559         .owner    = THIS_MODULE,
1560         .obj_size = sizeof(struct pppox_sock),
1561 };
1562
1563 /* socket() handler. Initialize a new struct sock.
1564  */
1565 static int pppol2tp_create(struct net *net, struct socket *sock)
1566 {
1567         int error = -ENOMEM;
1568         struct sock *sk;
1569
1570         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
1571         if (!sk)
1572                 goto out;
1573
1574         sock_init_data(sock, sk);
1575
1576         sock->state  = SS_UNCONNECTED;
1577         sock->ops    = &pppol2tp_ops;
1578
1579         sk->sk_backlog_rcv = pppol2tp_recv_core;
1580         sk->sk_protocol    = PX_PROTO_OL2TP;
1581         sk->sk_family      = PF_PPPOX;
1582         sk->sk_state       = PPPOX_NONE;
1583         sk->sk_type        = SOCK_STREAM;
1584         sk->sk_destruct    = pppol2tp_session_destruct;
1585
1586         error = 0;
1587
1588 out:
1589         return error;
1590 }
1591
1592 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
1593  */
1594 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
1595                             int sockaddr_len, int flags)
1596 {
1597         struct sock *sk = sock->sk;
1598         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
1599         struct pppox_sock *po = pppox_sk(sk);
1600         struct sock *tunnel_sock = NULL;
1601         struct pppol2tp_session *session = NULL;
1602         struct pppol2tp_tunnel *tunnel;
1603         struct dst_entry *dst;
1604         int error = 0;
1605
1606         lock_sock(sk);
1607
1608         error = -EINVAL;
1609         if (sp->sa_protocol != PX_PROTO_OL2TP)
1610                 goto end;
1611
1612         /* Check for already bound sockets */
1613         error = -EBUSY;
1614         if (sk->sk_state & PPPOX_CONNECTED)
1615                 goto end;
1616
1617         /* We don't supporting rebinding anyway */
1618         error = -EALREADY;
1619         if (sk->sk_user_data)
1620                 goto end; /* socket is already attached */
1621
1622         /* Don't bind if s_tunnel is 0 */
1623         error = -EINVAL;
1624         if (sp->pppol2tp.s_tunnel == 0)
1625                 goto end;
1626
1627         /* Special case: prepare tunnel socket if s_session and
1628          * d_session is 0. Otherwise look up tunnel using supplied
1629          * tunnel id.
1630          */
1631         if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
1632                 tunnel_sock = pppol2tp_prepare_tunnel_socket(sp->pppol2tp.fd,
1633                                                              sp->pppol2tp.s_tunnel,
1634                                                              &error);
1635                 if (tunnel_sock == NULL)
1636                         goto end;
1637
1638                 tunnel = tunnel_sock->sk_user_data;
1639         } else {
1640                 tunnel = pppol2tp_tunnel_find(sp->pppol2tp.s_tunnel);
1641
1642                 /* Error if we can't find the tunnel */
1643                 error = -ENOENT;
1644                 if (tunnel == NULL)
1645                         goto end;
1646
1647                 tunnel_sock = tunnel->sock;
1648         }
1649
1650         /* Check that this session doesn't already exist */
1651         error = -EEXIST;
1652         session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session);
1653         if (session != NULL)
1654                 goto end;
1655
1656         /* Allocate and initialize a new session context. */
1657         session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL);
1658         if (session == NULL) {
1659                 error = -ENOMEM;
1660                 goto end;
1661         }
1662
1663         skb_queue_head_init(&session->reorder_q);
1664
1665         session->magic       = L2TP_SESSION_MAGIC;
1666         session->owner       = current->pid;
1667         session->sock        = sk;
1668         session->tunnel      = tunnel;
1669         session->tunnel_sock = tunnel_sock;
1670         session->tunnel_addr = sp->pppol2tp;
1671         sprintf(&session->name[0], "sess %hu/%hu",
1672                 session->tunnel_addr.s_tunnel,
1673                 session->tunnel_addr.s_session);
1674
1675         session->stats.tunnel_id  = session->tunnel_addr.s_tunnel;
1676         session->stats.session_id = session->tunnel_addr.s_session;
1677
1678         INIT_HLIST_NODE(&session->hlist);
1679
1680         /* Inherit debug options from tunnel */
1681         session->debug = tunnel->debug;
1682
1683         /* Default MTU must allow space for UDP/L2TP/PPP
1684          * headers.
1685          */
1686         session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
1687
1688         /* If PMTU discovery was enabled, use the MTU that was discovered */
1689         dst = sk_dst_get(sk);
1690         if (dst != NULL) {
1691                 u32 pmtu = dst_mtu(__sk_dst_get(sk));
1692                 if (pmtu != 0)
1693                         session->mtu = session->mru = pmtu -
1694                                 PPPOL2TP_HEADER_OVERHEAD;
1695                 dst_release(dst);
1696         }
1697
1698         /* Special case: if source & dest session_id == 0x0000, this socket is
1699          * being created to manage the tunnel. Don't add the session to the
1700          * session hash list, just set up the internal context for use by
1701          * ioctl() and sockopt() handlers.
1702          */
1703         if ((session->tunnel_addr.s_session == 0) &&
1704             (session->tunnel_addr.d_session == 0)) {
1705                 error = 0;
1706                 sk->sk_user_data = session;
1707                 goto out_no_ppp;
1708         }
1709
1710         /* Get tunnel context from the tunnel socket */
1711         tunnel = pppol2tp_sock_to_tunnel(tunnel_sock);
1712         if (tunnel == NULL) {
1713                 error = -EBADF;
1714                 goto end;
1715         }
1716
1717         /* Right now, because we don't have a way to push the incoming skb's
1718          * straight through the UDP layer, the only header we need to worry
1719          * about is the L2TP header. This size is different depending on
1720          * whether sequence numbers are enabled for the data channel.
1721          */
1722         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1723
1724         po->chan.private = sk;
1725         po->chan.ops     = &pppol2tp_chan_ops;
1726         po->chan.mtu     = session->mtu;
1727
1728         error = ppp_register_channel(&po->chan);
1729         if (error)
1730                 goto end_put_tun;
1731
1732         /* This is how we get the session context from the socket. */
1733         sk->sk_user_data = session;
1734
1735         /* Add session to the tunnel's hash list */
1736         write_lock_bh(&tunnel->hlist_lock);
1737         hlist_add_head(&session->hlist,
1738                        pppol2tp_session_id_hash(tunnel,
1739                                                 session->tunnel_addr.s_session));
1740         write_unlock_bh(&tunnel->hlist_lock);
1741
1742         atomic_inc(&pppol2tp_session_count);
1743
1744 out_no_ppp:
1745         pppol2tp_tunnel_inc_refcount(tunnel);
1746         sk->sk_state = PPPOX_CONNECTED;
1747         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1748                "%s: created\n", session->name);
1749
1750 end_put_tun:
1751         sock_put(tunnel_sock);
1752 end:
1753         release_sock(sk);
1754
1755         if (error != 0) {
1756                 if (session)
1757                         PRINTK(session->debug,
1758                                 PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1759                                 "%s: connect failed: %d\n",
1760                                 session->name, error);
1761                 else
1762                         PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1763                                 "connect failed: %d\n", error);
1764         }
1765
1766         return error;
1767 }
1768
1769 /* getname() support.
1770  */
1771 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
1772                             int *usockaddr_len, int peer)
1773 {
1774         int len = sizeof(struct sockaddr_pppol2tp);
1775         struct sockaddr_pppol2tp sp;
1776         int error = 0;
1777         struct pppol2tp_session *session;
1778
1779         error = -ENOTCONN;
1780         if (sock->sk->sk_state != PPPOX_CONNECTED)
1781                 goto end;
1782
1783         session = pppol2tp_sock_to_session(sock->sk);
1784         if (session == NULL) {
1785                 error = -EBADF;
1786                 goto end;
1787         }
1788
1789         sp.sa_family    = AF_PPPOX;
1790         sp.sa_protocol  = PX_PROTO_OL2TP;
1791         memcpy(&sp.pppol2tp, &session->tunnel_addr,
1792                sizeof(struct pppol2tp_addr));
1793
1794         memcpy(uaddr, &sp, len);
1795
1796         *usockaddr_len = len;
1797
1798         error = 0;
1799         sock_put(sock->sk);
1800
1801 end:
1802         return error;
1803 }
1804
1805 /****************************************************************************
1806  * ioctl() handlers.
1807  *
1808  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1809  * sockets. However, in order to control kernel tunnel features, we allow
1810  * userspace to create a special "tunnel" PPPoX socket which is used for
1811  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
1812  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1813  * calls.
1814  ****************************************************************************/
1815
1816 /* Session ioctl helper.
1817  */
1818 static int pppol2tp_session_ioctl(struct pppol2tp_session *session,
1819                                   unsigned int cmd, unsigned long arg)
1820 {
1821         struct ifreq ifr;
1822         int err = 0;
1823         struct sock *sk = session->sock;
1824         int val = (int) arg;
1825
1826         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1827                "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1828                session->name, cmd, arg);
1829
1830         sock_hold(sk);
1831
1832         switch (cmd) {
1833         case SIOCGIFMTU:
1834                 err = -ENXIO;
1835                 if (!(sk->sk_state & PPPOX_CONNECTED))
1836                         break;
1837
1838                 err = -EFAULT;
1839                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1840                         break;
1841                 ifr.ifr_mtu = session->mtu;
1842                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1843                         break;
1844
1845                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1846                        "%s: get mtu=%d\n", session->name, session->mtu);
1847                 err = 0;
1848                 break;
1849
1850         case SIOCSIFMTU:
1851                 err = -ENXIO;
1852                 if (!(sk->sk_state & PPPOX_CONNECTED))
1853                         break;
1854
1855                 err = -EFAULT;
1856                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1857                         break;
1858
1859                 session->mtu = ifr.ifr_mtu;
1860
1861                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1862                        "%s: set mtu=%d\n", session->name, session->mtu);
1863                 err = 0;
1864                 break;
1865
1866         case PPPIOCGMRU:
1867                 err = -ENXIO;
1868                 if (!(sk->sk_state & PPPOX_CONNECTED))
1869                         break;
1870
1871                 err = -EFAULT;
1872                 if (put_user(session->mru, (int __user *) arg))
1873                         break;
1874
1875                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1876                        "%s: get mru=%d\n", session->name, session->mru);
1877                 err = 0;
1878                 break;
1879
1880         case PPPIOCSMRU:
1881                 err = -ENXIO;
1882                 if (!(sk->sk_state & PPPOX_CONNECTED))
1883                         break;
1884
1885                 err = -EFAULT;
1886                 if (get_user(val,(int __user *) arg))
1887                         break;
1888
1889                 session->mru = val;
1890                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1891                        "%s: set mru=%d\n", session->name, session->mru);
1892                 err = 0;
1893                 break;
1894
1895         case PPPIOCGFLAGS:
1896                 err = -EFAULT;
1897                 if (put_user(session->flags, (int __user *) arg))
1898                         break;
1899
1900                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1901                        "%s: get flags=%d\n", session->name, session->flags);
1902                 err = 0;
1903                 break;
1904
1905         case PPPIOCSFLAGS:
1906                 err = -EFAULT;
1907                 if (get_user(val, (int __user *) arg))
1908                         break;
1909                 session->flags = val;
1910                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1911                        "%s: set flags=%d\n", session->name, session->flags);
1912                 err = 0;
1913                 break;
1914
1915         case PPPIOCGL2TPSTATS:
1916                 err = -ENXIO;
1917                 if (!(sk->sk_state & PPPOX_CONNECTED))
1918                         break;
1919
1920                 if (copy_to_user((void __user *) arg, &session->stats,
1921                                  sizeof(session->stats)))
1922                         break;
1923                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1924                        "%s: get L2TP stats\n", session->name);
1925                 err = 0;
1926                 break;
1927
1928         default:
1929                 err = -ENOSYS;
1930                 break;
1931         }
1932
1933         sock_put(sk);
1934
1935         return err;
1936 }
1937
1938 /* Tunnel ioctl helper.
1939  *
1940  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1941  * specifies a session_id, the session ioctl handler is called. This allows an
1942  * application to retrieve session stats via a tunnel socket.
1943  */
1944 static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel,
1945                                  unsigned int cmd, unsigned long arg)
1946 {
1947         int err = 0;
1948         struct sock *sk = tunnel->sock;
1949         struct pppol2tp_ioc_stats stats_req;
1950
1951         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1952                "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name,
1953                cmd, arg);
1954
1955         sock_hold(sk);
1956
1957         switch (cmd) {
1958         case PPPIOCGL2TPSTATS:
1959                 err = -ENXIO;
1960                 if (!(sk->sk_state & PPPOX_CONNECTED))
1961                         break;
1962
1963                 if (copy_from_user(&stats_req, (void __user *) arg,
1964                                    sizeof(stats_req))) {
1965                         err = -EFAULT;
1966                         break;
1967                 }
1968                 if (stats_req.session_id != 0) {
1969                         /* resend to session ioctl handler */
1970                         struct pppol2tp_session *session =
1971                                 pppol2tp_session_find(tunnel, stats_req.session_id);
1972                         if (session != NULL)
1973                                 err = pppol2tp_session_ioctl(session, cmd, arg);
1974                         else
1975                                 err = -EBADR;
1976                         break;
1977                 }
1978 #ifdef CONFIG_XFRM
1979                 tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
1980 #endif
1981                 if (copy_to_user((void __user *) arg, &tunnel->stats,
1982                                  sizeof(tunnel->stats))) {
1983                         err = -EFAULT;
1984                         break;
1985                 }
1986                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1987                        "%s: get L2TP stats\n", tunnel->name);
1988                 err = 0;
1989                 break;
1990
1991         default:
1992                 err = -ENOSYS;
1993                 break;
1994         }
1995
1996         sock_put(sk);
1997
1998         return err;
1999 }
2000
2001 /* Main ioctl() handler.
2002  * Dispatch to tunnel or session helpers depending on the socket.
2003  */
2004 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
2005                           unsigned long arg)
2006 {
2007         struct sock *sk = sock->sk;
2008         struct pppol2tp_session *session;
2009         struct pppol2tp_tunnel *tunnel;
2010         int err;
2011
2012         if (!sk)
2013                 return 0;
2014
2015         err = -EBADF;
2016         if (sock_flag(sk, SOCK_DEAD) != 0)
2017                 goto end;
2018
2019         err = -ENOTCONN;
2020         if ((sk->sk_user_data == NULL) ||
2021             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
2022                 goto end;
2023
2024         /* Get session context from the socket */
2025         err = -EBADF;
2026         session = pppol2tp_sock_to_session(sk);
2027         if (session == NULL)
2028                 goto end;
2029
2030         /* Special case: if session's session_id is zero, treat ioctl as a
2031          * tunnel ioctl
2032          */
2033         if ((session->tunnel_addr.s_session == 0) &&
2034             (session->tunnel_addr.d_session == 0)) {
2035                 err = -EBADF;
2036                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2037                 if (tunnel == NULL)
2038                         goto end_put_sess;
2039
2040                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
2041                 sock_put(session->tunnel_sock);
2042                 goto end_put_sess;
2043         }
2044
2045         err = pppol2tp_session_ioctl(session, cmd, arg);
2046
2047 end_put_sess:
2048         sock_put(sk);
2049 end:
2050         return err;
2051 }
2052
2053 /*****************************************************************************
2054  * setsockopt() / getsockopt() support.
2055  *
2056  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
2057  * sockets. In order to control kernel tunnel features, we allow userspace to
2058  * create a special "tunnel" PPPoX socket which is used for control only.
2059  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
2060  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
2061  *****************************************************************************/
2062
2063 /* Tunnel setsockopt() helper.
2064  */
2065 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
2066                                       struct pppol2tp_tunnel *tunnel,
2067                                       int optname, int val)
2068 {
2069         int err = 0;
2070
2071         switch (optname) {
2072         case PPPOL2TP_SO_DEBUG:
2073                 tunnel->debug = val;
2074                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2075                        "%s: set debug=%x\n", tunnel->name, tunnel->debug);
2076                 break;
2077
2078         default:
2079                 err = -ENOPROTOOPT;
2080                 break;
2081         }
2082
2083         return err;
2084 }
2085
2086 /* Session setsockopt helper.
2087  */
2088 static int pppol2tp_session_setsockopt(struct sock *sk,
2089                                        struct pppol2tp_session *session,
2090                                        int optname, int val)
2091 {
2092         int err = 0;
2093
2094         switch (optname) {
2095         case PPPOL2TP_SO_RECVSEQ:
2096                 if ((val != 0) && (val != 1)) {
2097                         err = -EINVAL;
2098                         break;
2099                 }
2100                 session->recv_seq = val ? -1 : 0;
2101                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2102                        "%s: set recv_seq=%d\n", session->name,
2103                        session->recv_seq);
2104                 break;
2105
2106         case PPPOL2TP_SO_SENDSEQ:
2107                 if ((val != 0) && (val != 1)) {
2108                         err = -EINVAL;
2109                         break;
2110                 }
2111                 session->send_seq = val ? -1 : 0;
2112                 {
2113                         struct sock *ssk      = session->sock;
2114                         struct pppox_sock *po = pppox_sk(ssk);
2115                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
2116                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
2117                 }
2118                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2119                        "%s: set send_seq=%d\n", session->name, session->send_seq);
2120                 break;
2121
2122         case PPPOL2TP_SO_LNSMODE:
2123                 if ((val != 0) && (val != 1)) {
2124                         err = -EINVAL;
2125                         break;
2126                 }
2127                 session->lns_mode = val ? -1 : 0;
2128                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2129                        "%s: set lns_mode=%d\n", session->name,
2130                        session->lns_mode);
2131                 break;
2132
2133         case PPPOL2TP_SO_DEBUG:
2134                 session->debug = val;
2135                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2136                        "%s: set debug=%x\n", session->name, session->debug);
2137                 break;
2138
2139         case PPPOL2TP_SO_REORDERTO:
2140                 session->reorder_timeout = msecs_to_jiffies(val);
2141                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2142                        "%s: set reorder_timeout=%d\n", session->name,
2143                        session->reorder_timeout);
2144                 break;
2145
2146         default:
2147                 err = -ENOPROTOOPT;
2148                 break;
2149         }
2150
2151         return err;
2152 }
2153
2154 /* Main setsockopt() entry point.
2155  * Does API checks, then calls either the tunnel or session setsockopt
2156  * handler, according to whether the PPPoL2TP socket is a for a regular
2157  * session or the special tunnel type.
2158  */
2159 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
2160                                char __user *optval, int optlen)
2161 {
2162         struct sock *sk = sock->sk;
2163         struct pppol2tp_session *session = sk->sk_user_data;
2164         struct pppol2tp_tunnel *tunnel;
2165         int val;
2166         int err;
2167
2168         if (level != SOL_PPPOL2TP)
2169                 return udp_prot.setsockopt(sk, level, optname, optval, optlen);
2170
2171         if (optlen < sizeof(int))
2172                 return -EINVAL;
2173
2174         if (get_user(val, (int __user *)optval))
2175                 return -EFAULT;
2176
2177         err = -ENOTCONN;
2178         if (sk->sk_user_data == NULL)
2179                 goto end;
2180
2181         /* Get session context from the socket */
2182         err = -EBADF;
2183         session = pppol2tp_sock_to_session(sk);
2184         if (session == NULL)
2185                 goto end;
2186
2187         /* Special case: if session_id == 0x0000, treat as operation on tunnel
2188          */
2189         if ((session->tunnel_addr.s_session == 0) &&
2190             (session->tunnel_addr.d_session == 0)) {
2191                 err = -EBADF;
2192                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2193                 if (tunnel == NULL)
2194                         goto end_put_sess;
2195
2196                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
2197                 sock_put(session->tunnel_sock);
2198         } else
2199                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
2200
2201         err = 0;
2202
2203 end_put_sess:
2204         sock_put(sk);
2205 end:
2206         return err;
2207 }
2208
2209 /* Tunnel getsockopt helper. Called with sock locked.
2210  */
2211 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
2212                                       struct pppol2tp_tunnel *tunnel,
2213                                       int optname, int *val)
2214 {
2215         int err = 0;
2216
2217         switch (optname) {
2218         case PPPOL2TP_SO_DEBUG:
2219                 *val = tunnel->debug;
2220                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2221                        "%s: get debug=%x\n", tunnel->name, tunnel->debug);
2222                 break;
2223
2224         default:
2225                 err = -ENOPROTOOPT;
2226                 break;
2227         }
2228
2229         return err;
2230 }
2231
2232 /* Session getsockopt helper. Called with sock locked.
2233  */
2234 static int pppol2tp_session_getsockopt(struct sock *sk,
2235                                        struct pppol2tp_session *session,
2236                                        int optname, int *val)
2237 {
2238         int err = 0;
2239
2240         switch (optname) {
2241         case PPPOL2TP_SO_RECVSEQ:
2242                 *val = session->recv_seq;
2243                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2244                        "%s: get recv_seq=%d\n", session->name, *val);
2245                 break;
2246
2247         case PPPOL2TP_SO_SENDSEQ:
2248                 *val = session->send_seq;
2249                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2250                        "%s: get send_seq=%d\n", session->name, *val);
2251                 break;
2252
2253         case PPPOL2TP_SO_LNSMODE:
2254                 *val = session->lns_mode;
2255                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2256                        "%s: get lns_mode=%d\n", session->name, *val);
2257                 break;
2258
2259         case PPPOL2TP_SO_DEBUG:
2260                 *val = session->debug;
2261                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2262                        "%s: get debug=%d\n", session->name, *val);
2263                 break;
2264
2265         case PPPOL2TP_SO_REORDERTO:
2266                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
2267                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2268                        "%s: get reorder_timeout=%d\n", session->name, *val);
2269                 break;
2270
2271         default:
2272                 err = -ENOPROTOOPT;
2273         }
2274
2275         return err;
2276 }
2277
2278 /* Main getsockopt() entry point.
2279  * Does API checks, then calls either the tunnel or session getsockopt
2280  * handler, according to whether the PPPoX socket is a for a regular session
2281  * or the special tunnel type.
2282  */
2283 static int pppol2tp_getsockopt(struct socket *sock, int level,
2284                                int optname, char __user *optval, int __user *optlen)
2285 {
2286         struct sock *sk = sock->sk;
2287         struct pppol2tp_session *session = sk->sk_user_data;
2288         struct pppol2tp_tunnel *tunnel;
2289         int val, len;
2290         int err;
2291
2292         if (level != SOL_PPPOL2TP)
2293                 return udp_prot.getsockopt(sk, level, optname, optval, optlen);
2294
2295         if (get_user(len, (int __user *) optlen))
2296                 return -EFAULT;
2297
2298         len = min_t(unsigned int, len, sizeof(int));
2299
2300         if (len < 0)
2301                 return -EINVAL;
2302
2303         err = -ENOTCONN;
2304         if (sk->sk_user_data == NULL)
2305                 goto end;
2306
2307         /* Get the session context */
2308         err = -EBADF;
2309         session = pppol2tp_sock_to_session(sk);
2310         if (session == NULL)
2311                 goto end;
2312
2313         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
2314         if ((session->tunnel_addr.s_session == 0) &&
2315             (session->tunnel_addr.d_session == 0)) {
2316                 err = -EBADF;
2317                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2318                 if (tunnel == NULL)
2319                         goto end_put_sess;
2320
2321                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
2322                 sock_put(session->tunnel_sock);
2323         } else
2324                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
2325
2326         err = -EFAULT;
2327         if (put_user(len, (int __user *) optlen))
2328                 goto end_put_sess;
2329
2330         if (copy_to_user((void __user *) optval, &val, len))
2331                 goto end_put_sess;
2332
2333         err = 0;
2334
2335 end_put_sess:
2336         sock_put(sk);
2337 end:
2338         return err;
2339 }
2340
2341 /*****************************************************************************
2342  * /proc filesystem for debug
2343  *****************************************************************************/
2344
2345 #ifdef CONFIG_PROC_FS
2346
2347 #include <linux/seq_file.h>
2348
2349 struct pppol2tp_seq_data {
2350         struct pppol2tp_tunnel *tunnel; /* current tunnel */
2351         struct pppol2tp_session *session; /* NULL means get first session in tunnel */
2352 };
2353
2354 static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
2355 {
2356         struct pppol2tp_session *session = NULL;
2357         struct hlist_node *walk;
2358         int found = 0;
2359         int next = 0;
2360         int i;
2361
2362         read_lock_bh(&tunnel->hlist_lock);
2363         for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) {
2364                 hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) {
2365                         if (curr == NULL) {
2366                                 found = 1;
2367                                 goto out;
2368                         }
2369                         if (session == curr) {
2370                                 next = 1;
2371                                 continue;
2372                         }
2373                         if (next) {
2374                                 found = 1;
2375                                 goto out;
2376                         }
2377                 }
2378         }
2379 out:
2380         read_unlock_bh(&tunnel->hlist_lock);
2381         if (!found)
2382                 session = NULL;
2383
2384         return session;
2385 }
2386
2387 static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_tunnel *curr)
2388 {
2389         struct pppol2tp_tunnel *tunnel = NULL;
2390
2391         read_lock_bh(&pppol2tp_tunnel_list_lock);
2392         if (list_is_last(&curr->list, &pppol2tp_tunnel_list)) {
2393                 goto out;
2394         }
2395         tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
2396 out:
2397         read_unlock_bh(&pppol2tp_tunnel_list_lock);
2398
2399         return tunnel;
2400 }
2401
2402 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
2403 {
2404         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
2405         loff_t pos = *offs;
2406
2407         if (!pos)
2408                 goto out;
2409
2410         BUG_ON(m->private == NULL);
2411         pd = m->private;
2412
2413         if (pd->tunnel == NULL) {
2414                 if (!list_empty(&pppol2tp_tunnel_list))
2415                         pd->tunnel = list_entry(pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
2416         } else {
2417                 pd->session = next_session(pd->tunnel, pd->session);
2418                 if (pd->session == NULL) {
2419                         pd->tunnel = next_tunnel(pd->tunnel);
2420                 }
2421         }
2422
2423         /* NULL tunnel and session indicates end of list */
2424         if ((pd->tunnel == NULL) && (pd->session == NULL))
2425                 pd = NULL;
2426
2427 out:
2428         return pd;
2429 }
2430
2431 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
2432 {
2433         (*pos)++;
2434         return NULL;
2435 }
2436
2437 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
2438 {
2439         /* nothing to do */
2440 }
2441
2442 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
2443 {
2444         struct pppol2tp_tunnel *tunnel = v;
2445
2446         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
2447                    tunnel->name,
2448                    (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N',
2449                    atomic_read(&tunnel->ref_count) - 1);
2450         seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n",
2451                    tunnel->debug,
2452                    (unsigned long long)tunnel->stats.tx_packets,
2453                    (unsigned long long)tunnel->stats.tx_bytes,
2454                    (unsigned long long)tunnel->stats.tx_errors,
2455                    (unsigned long long)tunnel->stats.rx_packets,
2456                    (unsigned long long)tunnel->stats.rx_bytes,
2457                    (unsigned long long)tunnel->stats.rx_errors);
2458 }
2459
2460 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
2461 {
2462         struct pppol2tp_session *session = v;
2463
2464         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
2465                    "%04X/%04X %d %c\n",
2466                    session->name,
2467                    ntohl(session->tunnel_addr.addr.sin_addr.s_addr),
2468                    ntohs(session->tunnel_addr.addr.sin_port),
2469                    session->tunnel_addr.s_tunnel,
2470                    session->tunnel_addr.s_session,
2471                    session->tunnel_addr.d_tunnel,
2472                    session->tunnel_addr.d_session,
2473                    session->sock->sk_state,
2474                    (session == session->sock->sk_user_data) ?
2475                    'Y' : 'N');
2476         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
2477                    session->mtu, session->mru,
2478                    session->recv_seq ? 'R' : '-',
2479                    session->send_seq ? 'S' : '-',
2480                    session->lns_mode ? "LNS" : "LAC",
2481                    session->debug,
2482                    jiffies_to_msecs(session->reorder_timeout));
2483         seq_printf(m, "   %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n",
2484                    session->nr, session->ns,
2485                    (unsigned long long)session->stats.tx_packets,
2486                    (unsigned long long)session->stats.tx_bytes,
2487                    (unsigned long long)session->stats.tx_errors,
2488                    (unsigned long long)session->stats.rx_packets,
2489                    (unsigned long long)session->stats.rx_bytes,
2490                    (unsigned long long)session->stats.rx_errors);
2491 }
2492
2493 static int pppol2tp_seq_show(struct seq_file *m, void *v)
2494 {
2495         struct pppol2tp_seq_data *pd = v;
2496
2497         /* display header on line 1 */
2498         if (v == SEQ_START_TOKEN) {
2499                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
2500                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
2501                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2502                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
2503                          "dest-tid/sid state user-data-ok\n");
2504                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
2505                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2506                 goto out;
2507         }
2508
2509         /* Show the tunnel or session context.
2510          */
2511         if (pd->session == NULL)
2512                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
2513         else
2514                 pppol2tp_seq_session_show(m, pd->session);
2515
2516 out:
2517         return 0;
2518 }
2519
2520 static struct seq_operations pppol2tp_seq_ops = {
2521         .start          = pppol2tp_seq_start,
2522         .next           = pppol2tp_seq_next,
2523         .stop           = pppol2tp_seq_stop,
2524         .show           = pppol2tp_seq_show,
2525 };
2526
2527 /* Called when our /proc file is opened. We allocate data for use when
2528  * iterating our tunnel / session contexts and store it in the private
2529  * data of the seq_file.
2530  */
2531 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
2532 {
2533         struct seq_file *m;
2534         struct pppol2tp_seq_data *pd;
2535         int ret = 0;
2536
2537         ret = seq_open(file, &pppol2tp_seq_ops);
2538         if (ret < 0)
2539                 goto out;
2540
2541         m = file->private_data;
2542
2543         /* Allocate and fill our proc_data for access later */
2544         ret = -ENOMEM;
2545         m->private = kzalloc(sizeof(struct pppol2tp_seq_data), GFP_KERNEL);
2546         if (m->private == NULL)
2547                 goto out;
2548
2549         pd = m->private;
2550         ret = 0;
2551
2552 out:
2553         return ret;
2554 }
2555
2556 /* Called when /proc file access completes.
2557  */
2558 static int pppol2tp_proc_release(struct inode *inode, struct file *file)
2559 {
2560         struct seq_file *m = (struct seq_file *)file->private_data;
2561
2562         kfree(m->private);
2563         m->private = NULL;
2564
2565         return seq_release(inode, file);
2566 }
2567
2568 static struct file_operations pppol2tp_proc_fops = {
2569         .owner          = THIS_MODULE,
2570         .open           = pppol2tp_proc_open,
2571         .read           = seq_read,
2572         .llseek         = seq_lseek,
2573         .release        = pppol2tp_proc_release,
2574 };
2575
2576 static struct proc_dir_entry *pppol2tp_proc;
2577
2578 #endif /* CONFIG_PROC_FS */
2579
2580 /*****************************************************************************
2581  * Init and cleanup
2582  *****************************************************************************/
2583
2584 static struct proto_ops pppol2tp_ops = {
2585         .family         = AF_PPPOX,
2586         .owner          = THIS_MODULE,
2587         .release        = pppol2tp_release,
2588         .bind           = sock_no_bind,
2589         .connect        = pppol2tp_connect,
2590         .socketpair     = sock_no_socketpair,
2591         .accept         = sock_no_accept,
2592         .getname        = pppol2tp_getname,
2593         .poll           = datagram_poll,
2594         .listen         = sock_no_listen,
2595         .shutdown       = sock_no_shutdown,
2596         .setsockopt     = pppol2tp_setsockopt,
2597         .getsockopt     = pppol2tp_getsockopt,
2598         .sendmsg        = pppol2tp_sendmsg,
2599         .recvmsg        = pppol2tp_recvmsg,
2600         .mmap           = sock_no_mmap,
2601         .ioctl          = pppox_ioctl,
2602 };
2603
2604 static struct pppox_proto pppol2tp_proto = {
2605         .create         = pppol2tp_create,
2606         .ioctl          = pppol2tp_ioctl
2607 };
2608
2609 static int __init pppol2tp_init(void)
2610 {
2611         int err;
2612
2613         err = proto_register(&pppol2tp_sk_proto, 0);
2614         if (err)
2615                 goto out;
2616         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
2617         if (err)
2618                 goto out_unregister_pppol2tp_proto;
2619
2620 #ifdef CONFIG_PROC_FS
2621         pppol2tp_proc = proc_net_fops_create(&init_net, "pppol2tp", 0,
2622                                              &pppol2tp_proc_fops);
2623         if (!pppol2tp_proc) {
2624                 err = -ENOMEM;
2625                 goto out_unregister_pppox_proto;
2626         }
2627 #endif /* CONFIG_PROC_FS */
2628         printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
2629                PPPOL2TP_DRV_VERSION);
2630
2631 out:
2632         return err;
2633 #ifdef CONFIG_PROC_FS
2634 out_unregister_pppox_proto:
2635         unregister_pppox_proto(PX_PROTO_OL2TP);
2636 #endif
2637 out_unregister_pppol2tp_proto:
2638         proto_unregister(&pppol2tp_sk_proto);
2639         goto out;
2640 }
2641
2642 static void __exit pppol2tp_exit(void)
2643 {
2644         unregister_pppox_proto(PX_PROTO_OL2TP);
2645
2646 #ifdef CONFIG_PROC_FS
2647         remove_proc_entry("pppol2tp", init_net.proc_net);
2648 #endif
2649         proto_unregister(&pppol2tp_sk_proto);
2650 }
2651
2652 module_init(pppol2tp_init);
2653 module_exit(pppol2tp_exit);
2654
2655 MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, "
2656               "James Chapman <jchapman@katalix.com>");
2657 MODULE_DESCRIPTION("PPP over L2TP over UDP");
2658 MODULE_LICENSE("GPL");
2659 MODULE_VERSION(PPPOL2TP_DRV_VERSION);