net/l2tp/l2tp

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This source file includes following definitions.
pppol2tp_session_get_sock
pppol2tp_sock_to_session
pppol2tp_recvmsg
pppol2tp_recv
pppol2tp_sendmsg
pppol2tp_xmit
pppol2tp_put_sk
pppol2tp_session_destruct
pppol2tp_release
pppol2tp_backlog_recv
pppol2tp_create
pppol2tp_show
pppol2tp_session_init
pppol2tp_sockaddr_get_info
pppol2tp_tunnel_mtu
pppol2tp_connect
pppol2tp_session_create
pppol2tp_getname
pppol2tp_copy_stats
pppol2tp_tunnel_copy_stats
pppol2tp_ioctl
pppol2tp_tunnel_setsockopt
pppol2tp_session_setsockopt
pppol2tp_setsockopt
pppol2tp_tunnel_getsockopt
pppol2tp_session_getsockopt
pppol2tp_getsockopt
pppol2tp_next_tunnel
pppol2tp_next_session
pppol2tp_seq_start
pppol2tp_seq_next
pppol2tp_seq_stop
pppol2tp_seq_tunnel_show
pppol2tp_seq_session_show
pppol2tp_seq_show
pppol2tp_init_net
pppol2tp_exit_net
pppol2tp_init
pppol2tp_exit
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*****************************************************************************
   3  * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
   4  *
   5  * PPPoX    --- Generic PPP encapsulation socket family
   6  * PPPoL2TP --- PPP over L2TP (RFC 2661)
   7  *
   8  * Version:     2.0.0
   9  *
  10  * Authors:     James Chapman (jchapman@katalix.com)
  11  *
  12  * Based on original work by Martijn van Oosterhout <kleptog@svana.org>
  13  *
  14  * License:
  15  */
  16 
  17 /* This driver handles only L2TP data frames; control frames are handled by a
  18  * userspace application.
  19  *
  20  * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
  21  * attaches it to a bound UDP socket with local tunnel_id / session_id and
  22  * peer tunnel_id / session_id set. Data can then be sent or received using
  23  * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
  24  * can be read or modified using ioctl() or [gs]etsockopt() calls.
  25  *
  26  * When a PPPoL2TP socket is connected with local and peer session_id values
  27  * zero, the socket is treated as a special tunnel management socket.
  28  *
  29  * Here's example userspace code to create a socket for sending/receiving data
  30  * over an L2TP session:-
  31  *
  32  *      struct sockaddr_pppol2tp sax;
  33  *      int fd;
  34  *      int session_fd;
  35  *
  36  *      fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
  37  *
  38  *      sax.sa_family = AF_PPPOX;
  39  *      sax.sa_protocol = PX_PROTO_OL2TP;
  40  *      sax.pppol2tp.fd = tunnel_fd;    // bound UDP socket
  41  *      sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
  42  *      sax.pppol2tp.addr.sin_port = addr->sin_port;
  43  *      sax.pppol2tp.addr.sin_family = AF_INET;
  44  *      sax.pppol2tp.s_tunnel  = tunnel_id;
  45  *      sax.pppol2tp.s_session = session_id;
  46  *      sax.pppol2tp.d_tunnel  = peer_tunnel_id;
  47  *      sax.pppol2tp.d_session = peer_session_id;
  48  *
  49  *      session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
  50  *
  51  * A pppd plugin that allows PPP traffic to be carried over L2TP using
  52  * this driver is available from the OpenL2TP project at
  53  * http://openl2tp.sourceforge.net.
  54  */
  55 
  56 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  57 
  58 #include <linux/module.h>
  59 #include <linux/string.h>
  60 #include <linux/list.h>
  61 #include <linux/uaccess.h>
  62 
  63 #include <linux/kernel.h>
  64 #include <linux/spinlock.h>
  65 #include <linux/kthread.h>
  66 #include <linux/sched.h>
  67 #include <linux/slab.h>
  68 #include <linux/errno.h>
  69 #include <linux/jiffies.h>
  70 
  71 #include <linux/netdevice.h>
  72 #include <linux/net.h>
  73 #include <linux/inetdevice.h>
  74 #include <linux/skbuff.h>
  75 #include <linux/init.h>
  76 #include <linux/ip.h>
  77 #include <linux/udp.h>
  78 #include <linux/if_pppox.h>
  79 #include <linux/if_pppol2tp.h>
  80 #include <net/sock.h>
  81 #include <linux/ppp_channel.h>
  82 #include <linux/ppp_defs.h>
  83 #include <linux/ppp-ioctl.h>
  84 #include <linux/file.h>
  85 #include <linux/hash.h>
  86 #include <linux/sort.h>
  87 #include <linux/proc_fs.h>
  88 #include <linux/l2tp.h>
  89 #include <linux/nsproxy.h>
  90 #include <net/net_namespace.h>
  91 #include <net/netns/generic.h>
  92 #include <net/ip.h>
  93 #include <net/udp.h>
  94 #include <net/inet_common.h>
  95 
  96 #include <asm/byteorder.h>
  97 #include <linux/atomic.h>
  98 
  99 #include "l2tp_core.h"
 100 
 101 #define PPPOL2TP_DRV_VERSION    "V2.0"
 102 
 103 /* Space for UDP, L2TP and PPP headers */
 104 #define PPPOL2TP_HEADER_OVERHEAD        40
 105 
 106 /* Number of bytes to build transmit L2TP headers.
 107  * Unfortunately the size is different depending on whether sequence numbers
 108  * are enabled.
 109  */
 110 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ              10
 111 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ            6
 112 
 113 /* Private data of each session. This data lives at the end of struct
 114  * l2tp_session, referenced via session->priv[].
 115  */
 116 struct pppol2tp_session {
 117         int                     owner;          /* pid that opened the socket */
 118 
 119         struct mutex            sk_lock;        /* Protects .sk */
 120         struct sock __rcu       *sk;            /* Pointer to the session
 121                                                  * PPPoX socket */
 122         struct sock             *__sk;          /* Copy of .sk, for cleanup */
 123         struct rcu_head         rcu;            /* For asynchronous release */
 124 };
 125 
 126 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
 127 
 128 static const struct ppp_channel_ops pppol2tp_chan_ops = {
 129         .start_xmit =  pppol2tp_xmit,
 130 };
 131 
 132 static const struct proto_ops pppol2tp_ops;
 133 
 134 /* Retrieves the pppol2tp socket associated to a session.
 135  * A reference is held on the returned socket, so this function must be paired
 136  * with sock_put().
 137  */
 138 static struct sock *pppol2tp_session_get_sock(struct l2tp_session *session)
 139 {
 140         struct pppol2tp_session *ps = l2tp_session_priv(session);
 141         struct sock *sk;
 142 
 143         rcu_read_lock();
 144         sk = rcu_dereference(ps->sk);
 145         if (sk)
 146                 sock_hold(sk);
 147         rcu_read_unlock();
 148 
 149         return sk;
 150 }
 151 
 152 /* Helpers to obtain tunnel/session contexts from sockets.
 153  */
 154 static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
 155 {
 156         struct l2tp_session *session;
 157 
 158         if (sk == NULL)
 159                 return NULL;
 160 
 161         sock_hold(sk);
 162         session = (struct l2tp_session *)(sk->sk_user_data);
 163         if (session == NULL) {
 164                 sock_put(sk);
 165                 goto out;
 166         }
 167 
 168         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 169 
 170 out:
 171         return session;
 172 }
 173 
 174 /*****************************************************************************
 175  * Receive data handling
 176  *****************************************************************************/
 177 
 178 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
 179  */
 180 static int pppol2tp_recvmsg(struct socket *sock, struct msghdr *msg,
 181                             size_t len, int flags)
 182 {
 183         int err;
 184         struct sk_buff *skb;
 185         struct sock *sk = sock->sk;
 186 
 187         err = -EIO;
 188         if (sk->sk_state & PPPOX_BOUND)
 189                 goto end;
 190 
 191         err = 0;
 192         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 193                                 flags & MSG_DONTWAIT, &err);
 194         if (!skb)
 195                 goto end;
 196 
 197         if (len > skb->len)
 198                 len = skb->len;
 199         else if (len < skb->len)
 200                 msg->msg_flags |= MSG_TRUNC;
 201 
 202         err = skb_copy_datagram_msg(skb, 0, msg, len);
 203         if (likely(err == 0))
 204                 err = len;
 205 
 206         kfree_skb(skb);
 207 end:
 208         return err;
 209 }
 210 
 211 static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
 212 {
 213         struct pppol2tp_session *ps = l2tp_session_priv(session);
 214         struct sock *sk = NULL;
 215 
 216         /* If the socket is bound, send it in to PPP's input queue. Otherwise
 217          * queue it on the session socket.
 218          */
 219         rcu_read_lock();
 220         sk = rcu_dereference(ps->sk);
 221         if (sk == NULL)
 222                 goto no_sock;
 223 
 224         /* If the first two bytes are 0xFF03, consider that it is the PPP's
 225          * Address and Control fields and skip them. The L2TP module has always
 226          * worked this way, although, in theory, the use of these fields should
 227          * be negociated and handled at the PPP layer. These fields are
 228          * constant: 0xFF is the All-Stations Address and 0x03 the Unnumbered
 229          * Information command with Poll/Final bit set to zero (RFC 1662).
 230          */
 231         if (pskb_may_pull(skb, 2) && skb->data[0] == PPP_ALLSTATIONS &&
 232             skb->data[1] == PPP_UI)
 233                 skb_pull(skb, 2);
 234 
 235         if (sk->sk_state & PPPOX_BOUND) {
 236                 struct pppox_sock *po;
 237 
 238                 l2tp_dbg(session, L2TP_MSG_DATA,
 239                          "%s: recv %d byte data frame, passing to ppp\n",
 240                          session->name, data_len);
 241 
 242                 po = pppox_sk(sk);
 243                 ppp_input(&po->chan, skb);
 244         } else {
 245                 l2tp_dbg(session, L2TP_MSG_DATA,
 246                          "%s: recv %d byte data frame, passing to L2TP socket\n",
 247                          session->name, data_len);
 248 
 249                 if (sock_queue_rcv_skb(sk, skb) < 0) {
 250                         atomic_long_inc(&session->stats.rx_errors);
 251                         kfree_skb(skb);
 252                 }
 253         }
 254         rcu_read_unlock();
 255 
 256         return;
 257 
 258 no_sock:
 259         rcu_read_unlock();
 260         l2tp_info(session, L2TP_MSG_DATA, "%s: no socket\n", session->name);
 261         kfree_skb(skb);
 262 }
 263 
 264 /************************************************************************
 265  * Transmit handling
 266  ***********************************************************************/
 267 
 268 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
 269  * when a user application does a sendmsg() on the session socket. L2TP and
 270  * PPP headers must be inserted into the user's data.
 271  */
 272 static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
 273                             size_t total_len)
 274 {
 275         struct sock *sk = sock->sk;
 276         struct sk_buff *skb;
 277         int error;
 278         struct l2tp_session *session;
 279         struct l2tp_tunnel *tunnel;
 280         int uhlen;
 281 
 282         error = -ENOTCONN;
 283         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 284                 goto error;
 285 
 286         /* Get session and tunnel contexts */
 287         error = -EBADF;
 288         session = pppol2tp_sock_to_session(sk);
 289         if (session == NULL)
 290                 goto error;
 291 
 292         tunnel = session->tunnel;
 293 
 294         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
 295 
 296         /* Allocate a socket buffer */
 297         error = -ENOMEM;
 298         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
 299                            uhlen + session->hdr_len +
 300                            2 + total_len, /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
 301                            0, GFP_KERNEL);
 302         if (!skb)
 303                 goto error_put_sess;
 304 
 305         /* Reserve space for headers. */
 306         skb_reserve(skb, NET_SKB_PAD);
 307         skb_reset_network_header(skb);
 308         skb_reserve(skb, sizeof(struct iphdr));
 309         skb_reset_transport_header(skb);
 310         skb_reserve(skb, uhlen);
 311 
 312         /* Add PPP header */
 313         skb->data[0] = PPP_ALLSTATIONS;
 314         skb->data[1] = PPP_UI;
 315         skb_put(skb, 2);
 316 
 317         /* Copy user data into skb */
 318         error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
 319         if (error < 0) {
 320                 kfree_skb(skb);
 321                 goto error_put_sess;
 322         }
 323 
 324         local_bh_disable();
 325         l2tp_xmit_skb(session, skb, session->hdr_len);
 326         local_bh_enable();
 327 
 328         sock_put(sk);
 329 
 330         return total_len;
 331 
 332 error_put_sess:
 333         sock_put(sk);
 334 error:
 335         return error;
 336 }
 337 
 338 /* Transmit function called by generic PPP driver.  Sends PPP frame
 339  * over PPPoL2TP socket.
 340  *
 341  * This is almost the same as pppol2tp_sendmsg(), but rather than
 342  * being called with a msghdr from userspace, it is called with a skb
 343  * from the kernel.
 344  *
 345  * The supplied skb from ppp doesn't have enough headroom for the
 346  * insertion of L2TP, UDP and IP headers so we need to allocate more
 347  * headroom in the skb. This will create a cloned skb. But we must be
 348  * careful in the error case because the caller will expect to free
 349  * the skb it supplied, not our cloned skb. So we take care to always
 350  * leave the original skb unfreed if we return an error.
 351  */
 352 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 353 {
 354         struct sock *sk = (struct sock *) chan->private;
 355         struct l2tp_session *session;
 356         struct l2tp_tunnel *tunnel;
 357         int uhlen, headroom;
 358 
 359         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 360                 goto abort;
 361 
 362         /* Get session and tunnel contexts from the socket */
 363         session = pppol2tp_sock_to_session(sk);
 364         if (session == NULL)
 365                 goto abort;
 366 
 367         tunnel = session->tunnel;
 368 
 369         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
 370         headroom = NET_SKB_PAD +
 371                    sizeof(struct iphdr) + /* IP header */
 372                    uhlen +              /* UDP header (if L2TP_ENCAPTYPE_UDP) */
 373                    session->hdr_len +   /* L2TP header */
 374                    2;                   /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
 375         if (skb_cow_head(skb, headroom))
 376                 goto abort_put_sess;
 377 
 378         /* Setup PPP header */
 379         __skb_push(skb, 2);
 380         skb->data[0] = PPP_ALLSTATIONS;
 381         skb->data[1] = PPP_UI;
 382 
 383         local_bh_disable();
 384         l2tp_xmit_skb(session, skb, session->hdr_len);
 385         local_bh_enable();
 386 
 387         sock_put(sk);
 388 
 389         return 1;
 390 
 391 abort_put_sess:
 392         sock_put(sk);
 393 abort:
 394         /* Free the original skb */
 395         kfree_skb(skb);
 396         return 1;
 397 }
 398 
 399 /*****************************************************************************
 400  * Session (and tunnel control) socket create/destroy.
 401  *****************************************************************************/
 402 
 403 static void pppol2tp_put_sk(struct rcu_head *head)
 404 {
 405         struct pppol2tp_session *ps;
 406 
 407         ps = container_of(head, typeof(*ps), rcu);
 408         sock_put(ps->__sk);
 409 }
 410 
 411 /* Really kill the session socket. (Called from sock_put() if
 412  * refcnt == 0.)
 413  */
 414 static void pppol2tp_session_destruct(struct sock *sk)
 415 {
 416         struct l2tp_session *session = sk->sk_user_data;
 417 
 418         skb_queue_purge(&sk->sk_receive_queue);
 419         skb_queue_purge(&sk->sk_write_queue);
 420 
 421         if (session) {
 422                 sk->sk_user_data = NULL;
 423                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 424                 l2tp_session_dec_refcount(session);
 425         }
 426 }
 427 
 428 /* Called when the PPPoX socket (session) is closed.
 429  */
 430 static int pppol2tp_release(struct socket *sock)
 431 {
 432         struct sock *sk = sock->sk;
 433         struct l2tp_session *session;
 434         int error;
 435 
 436         if (!sk)
 437                 return 0;
 438 
 439         error = -EBADF;
 440         lock_sock(sk);
 441         if (sock_flag(sk, SOCK_DEAD) != 0)
 442                 goto error;
 443 
 444         pppox_unbind_sock(sk);
 445 
 446         /* Signal the death of the socket. */
 447         sk->sk_state = PPPOX_DEAD;
 448         sock_orphan(sk);
 449         sock->sk = NULL;
 450 
 451         session = pppol2tp_sock_to_session(sk);
 452         if (session) {
 453                 struct pppol2tp_session *ps;
 454 
 455                 l2tp_session_delete(session);
 456 
 457                 ps = l2tp_session_priv(session);
 458                 mutex_lock(&ps->sk_lock);
 459                 ps->__sk = rcu_dereference_protected(ps->sk,
 460                                                      lockdep_is_held(&ps->sk_lock));
 461                 RCU_INIT_POINTER(ps->sk, NULL);
 462                 mutex_unlock(&ps->sk_lock);
 463                 call_rcu(&ps->rcu, pppol2tp_put_sk);
 464 
 465                 /* Rely on the sock_put() call at the end of the function for
 466                  * dropping the reference held by pppol2tp_sock_to_session().
 467                  * The last reference will be dropped by pppol2tp_put_sk().
 468                  */
 469         }
 470 
 471         release_sock(sk);
 472 
 473         /* This will delete the session context via
 474          * pppol2tp_session_destruct() if the socket's refcnt drops to
 475          * zero.
 476          */
 477         sock_put(sk);
 478 
 479         return 0;
 480 
 481 error:
 482         release_sock(sk);
 483         return error;
 484 }
 485 
 486 static struct proto pppol2tp_sk_proto = {
 487         .name     = "PPPOL2TP",
 488         .owner    = THIS_MODULE,
 489         .obj_size = sizeof(struct pppox_sock),
 490 };
 491 
 492 static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
 493 {
 494         int rc;
 495 
 496         rc = l2tp_udp_encap_recv(sk, skb);
 497         if (rc)
 498                 kfree_skb(skb);
 499 
 500         return NET_RX_SUCCESS;
 501 }
 502 
 503 /* socket() handler. Initialize a new struct sock.
 504  */
 505 static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
 506 {
 507         int error = -ENOMEM;
 508         struct sock *sk;
 509 
 510         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto, kern);
 511         if (!sk)
 512                 goto out;
 513 
 514         sock_init_data(sock, sk);
 515 
 516         sock->state  = SS_UNCONNECTED;
 517         sock->ops    = &pppol2tp_ops;
 518 
 519         sk->sk_backlog_rcv = pppol2tp_backlog_recv;
 520         sk->sk_protocol    = PX_PROTO_OL2TP;
 521         sk->sk_family      = PF_PPPOX;
 522         sk->sk_state       = PPPOX_NONE;
 523         sk->sk_type        = SOCK_STREAM;
 524         sk->sk_destruct    = pppol2tp_session_destruct;
 525 
 526         error = 0;
 527 
 528 out:
 529         return error;
 530 }
 531 
 532 static void pppol2tp_show(struct seq_file *m, void *arg)
 533 {
 534         struct l2tp_session *session = arg;
 535         struct sock *sk;
 536 
 537         sk = pppol2tp_session_get_sock(session);
 538         if (sk) {
 539                 struct pppox_sock *po = pppox_sk(sk);
 540 
 541                 seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
 542                 sock_put(sk);
 543         }
 544 }
 545 
 546 static void pppol2tp_session_init(struct l2tp_session *session)
 547 {
 548         struct pppol2tp_session *ps;
 549 
 550         session->recv_skb = pppol2tp_recv;
 551         if (IS_ENABLED(CONFIG_L2TP_DEBUGFS))
 552                 session->show = pppol2tp_show;
 553 
 554         ps = l2tp_session_priv(session);
 555         mutex_init(&ps->sk_lock);
 556         ps->owner = current->pid;
 557 }
 558 
 559 struct l2tp_connect_info {
 560         u8 version;
 561         int fd;
 562         u32 tunnel_id;
 563         u32 peer_tunnel_id;
 564         u32 session_id;
 565         u32 peer_session_id;
 566 };
 567 
 568 static int pppol2tp_sockaddr_get_info(const void *sa, int sa_len,
 569                                       struct l2tp_connect_info *info)
 570 {
 571         switch (sa_len) {
 572         case sizeof(struct sockaddr_pppol2tp):
 573         {
 574                 const struct sockaddr_pppol2tp *sa_v2in4 = sa;
 575 
 576                 if (sa_v2in4->sa_protocol != PX_PROTO_OL2TP)
 577                         return -EINVAL;
 578 
 579                 info->version = 2;
 580                 info->fd = sa_v2in4->pppol2tp.fd;
 581                 info->tunnel_id = sa_v2in4->pppol2tp.s_tunnel;
 582                 info->peer_tunnel_id = sa_v2in4->pppol2tp.d_tunnel;
 583                 info->session_id = sa_v2in4->pppol2tp.s_session;
 584                 info->peer_session_id = sa_v2in4->pppol2tp.d_session;
 585 
 586                 break;
 587         }
 588         case sizeof(struct sockaddr_pppol2tpv3):
 589         {
 590                 const struct sockaddr_pppol2tpv3 *sa_v3in4 = sa;
 591 
 592                 if (sa_v3in4->sa_protocol != PX_PROTO_OL2TP)
 593                         return -EINVAL;
 594 
 595                 info->version = 3;
 596                 info->fd = sa_v3in4->pppol2tp.fd;
 597                 info->tunnel_id = sa_v3in4->pppol2tp.s_tunnel;
 598                 info->peer_tunnel_id = sa_v3in4->pppol2tp.d_tunnel;
 599                 info->session_id = sa_v3in4->pppol2tp.s_session;
 600                 info->peer_session_id = sa_v3in4->pppol2tp.d_session;
 601 
 602                 break;
 603         }
 604         case sizeof(struct sockaddr_pppol2tpin6):
 605         {
 606                 const struct sockaddr_pppol2tpin6 *sa_v2in6 = sa;
 607 
 608                 if (sa_v2in6->sa_protocol != PX_PROTO_OL2TP)
 609                         return -EINVAL;
 610 
 611                 info->version = 2;
 612                 info->fd = sa_v2in6->pppol2tp.fd;
 613                 info->tunnel_id = sa_v2in6->pppol2tp.s_tunnel;
 614                 info->peer_tunnel_id = sa_v2in6->pppol2tp.d_tunnel;
 615                 info->session_id = sa_v2in6->pppol2tp.s_session;
 616                 info->peer_session_id = sa_v2in6->pppol2tp.d_session;
 617 
 618                 break;
 619         }
 620         case sizeof(struct sockaddr_pppol2tpv3in6):
 621         {
 622                 const struct sockaddr_pppol2tpv3in6 *sa_v3in6 = sa;
 623 
 624                 if (sa_v3in6->sa_protocol != PX_PROTO_OL2TP)
 625                         return -EINVAL;
 626 
 627                 info->version = 3;
 628                 info->fd = sa_v3in6->pppol2tp.fd;
 629                 info->tunnel_id = sa_v3in6->pppol2tp.s_tunnel;
 630                 info->peer_tunnel_id = sa_v3in6->pppol2tp.d_tunnel;
 631                 info->session_id = sa_v3in6->pppol2tp.s_session;
 632                 info->peer_session_id = sa_v3in6->pppol2tp.d_session;
 633 
 634                 break;
 635         }
 636         default:
 637                 return -EINVAL;
 638         }
 639 
 640         return 0;
 641 }
 642 
 643 /* Rough estimation of the maximum payload size a tunnel can transmit without
 644  * fragmenting at the lower IP layer. Assumes L2TPv2 with sequence
 645  * numbers and no IP option. Not quite accurate, but the result is mostly
 646  * unused anyway.
 647  */
 648 static int pppol2tp_tunnel_mtu(const struct l2tp_tunnel *tunnel)
 649 {
 650         int mtu;
 651 
 652         mtu = l2tp_tunnel_dst_mtu(tunnel);
 653         if (mtu <= PPPOL2TP_HEADER_OVERHEAD)
 654                 return 1500 - PPPOL2TP_HEADER_OVERHEAD;
 655 
 656         return mtu - PPPOL2TP_HEADER_OVERHEAD;
 657 }
 658 
 659 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
 660  */
 661 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 662                             int sockaddr_len, int flags)
 663 {
 664         struct sock *sk = sock->sk;
 665         struct pppox_sock *po = pppox_sk(sk);
 666         struct l2tp_session *session = NULL;
 667         struct l2tp_connect_info info;
 668         struct l2tp_tunnel *tunnel;
 669         struct pppol2tp_session *ps;
 670         struct l2tp_session_cfg cfg = { 0, };
 671         bool drop_refcnt = false;
 672         bool drop_tunnel = false;
 673         bool new_session = false;
 674         bool new_tunnel = false;
 675         int error;
 676 
 677         error = pppol2tp_sockaddr_get_info(uservaddr, sockaddr_len, &info);
 678         if (error < 0)
 679                 return error;
 680 
 681         lock_sock(sk);
 682 
 683         /* Check for already bound sockets */
 684         error = -EBUSY;
 685         if (sk->sk_state & PPPOX_CONNECTED)
 686                 goto end;
 687 
 688         /* We don't supporting rebinding anyway */
 689         error = -EALREADY;
 690         if (sk->sk_user_data)
 691                 goto end; /* socket is already attached */
 692 
 693         /* Don't bind if tunnel_id is 0 */
 694         error = -EINVAL;
 695         if (!info.tunnel_id)
 696                 goto end;
 697 
 698         tunnel = l2tp_tunnel_get(sock_net(sk), info.tunnel_id);
 699         if (tunnel)
 700                 drop_tunnel = true;
 701 
 702         /* Special case: create tunnel context if session_id and
 703          * peer_session_id is 0. Otherwise look up tunnel using supplied
 704          * tunnel id.
 705          */
 706         if (!info.session_id && !info.peer_session_id) {
 707                 if (tunnel == NULL) {
 708                         struct l2tp_tunnel_cfg tcfg = {
 709                                 .encap = L2TP_ENCAPTYPE_UDP,
 710                                 .debug = 0,
 711                         };
 712 
 713                         /* Prevent l2tp_tunnel_register() from trying to set up
 714                          * a kernel socket.
 715                          */
 716                         if (info.fd < 0) {
 717                                 error = -EBADF;
 718                                 goto end;
 719                         }
 720 
 721                         error = l2tp_tunnel_create(sock_net(sk), info.fd,
 722                                                    info.version,
 723                                                    info.tunnel_id,
 724                                                    info.peer_tunnel_id, &tcfg,
 725                                                    &tunnel);
 726                         if (error < 0)
 727                                 goto end;
 728 
 729                         l2tp_tunnel_inc_refcount(tunnel);
 730                         error = l2tp_tunnel_register(tunnel, sock_net(sk),
 731                                                      &tcfg);
 732                         if (error < 0) {
 733                                 kfree(tunnel);
 734                                 goto end;
 735                         }
 736                         drop_tunnel = true;
 737                         new_tunnel = true;
 738                 }
 739         } else {
 740                 /* Error if we can't find the tunnel */
 741                 error = -ENOENT;
 742                 if (tunnel == NULL)
 743                         goto end;
 744 
 745                 /* Error if socket is not prepped */
 746                 if (tunnel->sock == NULL)
 747                         goto end;
 748         }
 749 
 750         if (tunnel->peer_tunnel_id == 0)
 751                 tunnel->peer_tunnel_id = info.peer_tunnel_id;
 752 
 753         session = l2tp_tunnel_get_session(tunnel, info.session_id);
 754         if (session) {
 755                 drop_refcnt = true;
 756 
 757                 if (session->pwtype != L2TP_PWTYPE_PPP) {
 758                         error = -EPROTOTYPE;
 759                         goto end;
 760                 }
 761 
 762                 ps = l2tp_session_priv(session);
 763 
 764                 /* Using a pre-existing session is fine as long as it hasn't
 765                  * been connected yet.
 766                  */
 767                 mutex_lock(&ps->sk_lock);
 768                 if (rcu_dereference_protected(ps->sk,
 769                                               lockdep_is_held(&ps->sk_lock)) ||
 770                     ps->__sk) {
 771                         mutex_unlock(&ps->sk_lock);
 772                         error = -EEXIST;
 773                         goto end;
 774                 }
 775         } else {
 776                 cfg.pw_type = L2TP_PWTYPE_PPP;
 777 
 778                 session = l2tp_session_create(sizeof(struct pppol2tp_session),
 779                                               tunnel, info.session_id,
 780                                               info.peer_session_id, &cfg);
 781                 if (IS_ERR(session)) {
 782                         error = PTR_ERR(session);
 783                         goto end;
 784                 }
 785 
 786                 pppol2tp_session_init(session);
 787                 ps = l2tp_session_priv(session);
 788                 l2tp_session_inc_refcount(session);
 789 
 790                 mutex_lock(&ps->sk_lock);
 791                 error = l2tp_session_register(session, tunnel);
 792                 if (error < 0) {
 793                         mutex_unlock(&ps->sk_lock);
 794                         kfree(session);
 795                         goto end;
 796                 }
 797                 drop_refcnt = true;
 798                 new_session = true;
 799         }
 800 
 801         /* Special case: if source & dest session_id == 0x0000, this
 802          * socket is being created to manage the tunnel. Just set up
 803          * the internal context for use by ioctl() and sockopt()
 804          * handlers.
 805          */
 806         if ((session->session_id == 0) &&
 807             (session->peer_session_id == 0)) {
 808                 error = 0;
 809                 goto out_no_ppp;
 810         }
 811 
 812         /* The only header we need to worry about is the L2TP
 813          * header. This size is different depending on whether
 814          * sequence numbers are enabled for the data channel.
 815          */
 816         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
 817 
 818         po->chan.private = sk;
 819         po->chan.ops     = &pppol2tp_chan_ops;
 820         po->chan.mtu     = pppol2tp_tunnel_mtu(tunnel);
 821 
 822         error = ppp_register_net_channel(sock_net(sk), &po->chan);
 823         if (error) {
 824                 mutex_unlock(&ps->sk_lock);
 825                 goto end;
 826         }
 827 
 828 out_no_ppp:
 829         /* This is how we get the session context from the socket. */
 830         sk->sk_user_data = session;
 831         rcu_assign_pointer(ps->sk, sk);
 832         mutex_unlock(&ps->sk_lock);
 833 
 834         /* Keep the reference we've grabbed on the session: sk doesn't expect
 835          * the session to disappear. pppol2tp_session_destruct() is responsible
 836          * for dropping it.
 837          */
 838         drop_refcnt = false;
 839 
 840         sk->sk_state = PPPOX_CONNECTED;
 841         l2tp_info(session, L2TP_MSG_CONTROL, "%s: created\n",
 842                   session->name);
 843 
 844 end:
 845         if (error) {
 846                 if (new_session)
 847                         l2tp_session_delete(session);
 848                 if (new_tunnel)
 849                         l2tp_tunnel_delete(tunnel);
 850         }
 851         if (drop_refcnt)
 852                 l2tp_session_dec_refcount(session);
 853         if (drop_tunnel)
 854                 l2tp_tunnel_dec_refcount(tunnel);
 855         release_sock(sk);
 856 
 857         return error;
 858 }
 859 
 860 #ifdef CONFIG_L2TP_V3
 861 
 862 /* Called when creating sessions via the netlink interface. */
 863 static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
 864                                    u32 session_id, u32 peer_session_id,
 865                                    struct l2tp_session_cfg *cfg)
 866 {
 867         int error;
 868         struct l2tp_session *session;
 869 
 870         /* Error if tunnel socket is not prepped */
 871         if (!tunnel->sock) {
 872                 error = -ENOENT;
 873                 goto err;
 874         }
 875 
 876         /* Allocate and initialize a new session context. */
 877         session = l2tp_session_create(sizeof(struct pppol2tp_session),
 878                                       tunnel, session_id,
 879                                       peer_session_id, cfg);
 880         if (IS_ERR(session)) {
 881                 error = PTR_ERR(session);
 882                 goto err;
 883         }
 884 
 885         pppol2tp_session_init(session);
 886 
 887         error = l2tp_session_register(session, tunnel);
 888         if (error < 0)
 889                 goto err_sess;
 890 
 891         return 0;
 892 
 893 err_sess:
 894         kfree(session);
 895 err:
 896         return error;
 897 }
 898 
 899 #endif /* CONFIG_L2TP_V3 */
 900 
 901 /* getname() support.
 902  */
 903 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
 904                             int peer)
 905 {
 906         int len = 0;
 907         int error = 0;
 908         struct l2tp_session *session;
 909         struct l2tp_tunnel *tunnel;
 910         struct sock *sk = sock->sk;
 911         struct inet_sock *inet;
 912         struct pppol2tp_session *pls;
 913 
 914         error = -ENOTCONN;
 915         if (sk == NULL)
 916                 goto end;
 917         if (!(sk->sk_state & PPPOX_CONNECTED))
 918                 goto end;
 919 
 920         error = -EBADF;
 921         session = pppol2tp_sock_to_session(sk);
 922         if (session == NULL)
 923                 goto end;
 924 
 925         pls = l2tp_session_priv(session);
 926         tunnel = session->tunnel;
 927 
 928         inet = inet_sk(tunnel->sock);
 929         if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
 930                 struct sockaddr_pppol2tp sp;
 931                 len = sizeof(sp);
 932                 memset(&sp, 0, len);
 933                 sp.sa_family    = AF_PPPOX;
 934                 sp.sa_protocol  = PX_PROTO_OL2TP;
 935                 sp.pppol2tp.fd  = tunnel->fd;
 936                 sp.pppol2tp.pid = pls->owner;
 937                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
 938                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
 939                 sp.pppol2tp.s_session = session->session_id;
 940                 sp.pppol2tp.d_session = session->peer_session_id;
 941                 sp.pppol2tp.addr.sin_family = AF_INET;
 942                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
 943                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
 944                 memcpy(uaddr, &sp, len);
 945 #if IS_ENABLED(CONFIG_IPV6)
 946         } else if ((tunnel->version == 2) &&
 947                    (tunnel->sock->sk_family == AF_INET6)) {
 948                 struct sockaddr_pppol2tpin6 sp;
 949 
 950                 len = sizeof(sp);
 951                 memset(&sp, 0, len);
 952                 sp.sa_family    = AF_PPPOX;
 953                 sp.sa_protocol  = PX_PROTO_OL2TP;
 954                 sp.pppol2tp.fd  = tunnel->fd;
 955                 sp.pppol2tp.pid = pls->owner;
 956                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
 957                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
 958                 sp.pppol2tp.s_session = session->session_id;
 959                 sp.pppol2tp.d_session = session->peer_session_id;
 960                 sp.pppol2tp.addr.sin6_family = AF_INET6;
 961                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
 962                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
 963                        sizeof(tunnel->sock->sk_v6_daddr));
 964                 memcpy(uaddr, &sp, len);
 965         } else if ((tunnel->version == 3) &&
 966                    (tunnel->sock->sk_family == AF_INET6)) {
 967                 struct sockaddr_pppol2tpv3in6 sp;
 968 
 969                 len = sizeof(sp);
 970                 memset(&sp, 0, len);
 971                 sp.sa_family    = AF_PPPOX;
 972                 sp.sa_protocol  = PX_PROTO_OL2TP;
 973                 sp.pppol2tp.fd  = tunnel->fd;
 974                 sp.pppol2tp.pid = pls->owner;
 975                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
 976                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
 977                 sp.pppol2tp.s_session = session->session_id;
 978                 sp.pppol2tp.d_session = session->peer_session_id;
 979                 sp.pppol2tp.addr.sin6_family = AF_INET6;
 980                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
 981                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
 982                        sizeof(tunnel->sock->sk_v6_daddr));
 983                 memcpy(uaddr, &sp, len);
 984 #endif
 985         } else if (tunnel->version == 3) {
 986                 struct sockaddr_pppol2tpv3 sp;
 987                 len = sizeof(sp);
 988                 memset(&sp, 0, len);
 989                 sp.sa_family    = AF_PPPOX;
 990                 sp.sa_protocol  = PX_PROTO_OL2TP;
 991                 sp.pppol2tp.fd  = tunnel->fd;
 992                 sp.pppol2tp.pid = pls->owner;
 993                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
 994                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
 995                 sp.pppol2tp.s_session = session->session_id;
 996                 sp.pppol2tp.d_session = session->peer_session_id;
 997                 sp.pppol2tp.addr.sin_family = AF_INET;
 998                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
 999                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
1000                 memcpy(uaddr, &sp, len);
1001         }
1002 
1003         error = len;
1004 
1005         sock_put(sk);
1006 end:
1007         return error;
1008 }
1009 
1010 /****************************************************************************
1011  * ioctl() handlers.
1012  *
1013  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1014  * sockets. However, in order to control kernel tunnel features, we allow
1015  * userspace to create a special "tunnel" PPPoX socket which is used for
1016  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
1017  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1018  * calls.
1019  ****************************************************************************/
1020 
1021 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
1022                                 const struct l2tp_stats *stats)
1023 {
1024         memset(dest, 0, sizeof(*dest));
1025 
1026         dest->tx_packets = atomic_long_read(&stats->tx_packets);
1027         dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
1028         dest->tx_errors = atomic_long_read(&stats->tx_errors);
1029         dest->rx_packets = atomic_long_read(&stats->rx_packets);
1030         dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
1031         dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
1032         dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
1033         dest->rx_errors = atomic_long_read(&stats->rx_errors);
1034 }
1035 
1036 static int pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats *stats,
1037                                       struct l2tp_tunnel *tunnel)
1038 {
1039         struct l2tp_session *session;
1040 
1041         if (!stats->session_id) {
1042                 pppol2tp_copy_stats(stats, &tunnel->stats);
1043                 return 0;
1044         }
1045 
1046         /* If session_id is set, search the corresponding session in the
1047          * context of this tunnel and record the session's statistics.
1048          */
1049         session = l2tp_tunnel_get_session(tunnel, stats->session_id);
1050         if (!session)
1051                 return -EBADR;
1052 
1053         if (session->pwtype != L2TP_PWTYPE_PPP) {
1054                 l2tp_session_dec_refcount(session);
1055                 return -EBADR;
1056         }
1057 
1058         pppol2tp_copy_stats(stats, &session->stats);
1059         l2tp_session_dec_refcount(session);
1060 
1061         return 0;
1062 }
1063 
1064 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1065                           unsigned long arg)
1066 {
1067         struct pppol2tp_ioc_stats stats;
1068         struct l2tp_session *session;
1069 
1070         switch (cmd) {
1071         case PPPIOCGMRU:
1072         case PPPIOCGFLAGS:
1073                 session = sock->sk->sk_user_data;
1074                 if (!session)
1075                         return -ENOTCONN;
1076 
1077                 /* Not defined for tunnels */
1078                 if (!session->session_id && !session->peer_session_id)
1079                         return -ENOSYS;
1080 
1081                 if (put_user(0, (int __user *)arg))
1082                         return -EFAULT;
1083                 break;
1084 
1085         case PPPIOCSMRU:
1086         case PPPIOCSFLAGS:
1087                 session = sock->sk->sk_user_data;
1088                 if (!session)
1089                         return -ENOTCONN;
1090 
1091                 /* Not defined for tunnels */
1092                 if (!session->session_id && !session->peer_session_id)
1093                         return -ENOSYS;
1094 
1095                 if (!access_ok((int __user *)arg, sizeof(int)))
1096                         return -EFAULT;
1097                 break;
1098 
1099         case PPPIOCGL2TPSTATS:
1100                 session = sock->sk->sk_user_data;
1101                 if (!session)
1102                         return -ENOTCONN;
1103 
1104                 /* Session 0 represents the parent tunnel */
1105                 if (!session->session_id && !session->peer_session_id) {
1106                         u32 session_id;
1107                         int err;
1108 
1109                         if (copy_from_user(&stats, (void __user *)arg,
1110                                            sizeof(stats)))
1111                                 return -EFAULT;
1112 
1113                         session_id = stats.session_id;
1114                         err = pppol2tp_tunnel_copy_stats(&stats,
1115                                                          session->tunnel);
1116                         if (err < 0)
1117                                 return err;
1118 
1119                         stats.session_id = session_id;
1120                 } else {
1121                         pppol2tp_copy_stats(&stats, &session->stats);
1122                         stats.session_id = session->session_id;
1123                 }
1124                 stats.tunnel_id = session->tunnel->tunnel_id;
1125                 stats.using_ipsec = l2tp_tunnel_uses_xfrm(session->tunnel);
1126 
1127                 if (copy_to_user((void __user *)arg, &stats, sizeof(stats)))
1128                         return -EFAULT;
1129                 break;
1130 
1131         default:
1132                 return -ENOIOCTLCMD;
1133         }
1134 
1135         return 0;
1136 }
1137 
1138 /*****************************************************************************
1139  * setsockopt() / getsockopt() support.
1140  *
1141  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1142  * sockets. In order to control kernel tunnel features, we allow userspace to
1143  * create a special "tunnel" PPPoX socket which is used for control only.
1144  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1145  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1146  *****************************************************************************/
1147 
1148 /* Tunnel setsockopt() helper.
1149  */
1150 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1151                                       struct l2tp_tunnel *tunnel,
1152                                       int optname, int val)
1153 {
1154         int err = 0;
1155 
1156         switch (optname) {
1157         case PPPOL2TP_SO_DEBUG:
1158                 tunnel->debug = val;
1159                 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: set debug=%x\n",
1160                           tunnel->name, tunnel->debug);
1161                 break;
1162 
1163         default:
1164                 err = -ENOPROTOOPT;
1165                 break;
1166         }
1167 
1168         return err;
1169 }
1170 
1171 /* Session setsockopt helper.
1172  */
1173 static int pppol2tp_session_setsockopt(struct sock *sk,
1174                                        struct l2tp_session *session,
1175                                        int optname, int val)
1176 {
1177         int err = 0;
1178 
1179         switch (optname) {
1180         case PPPOL2TP_SO_RECVSEQ:
1181                 if ((val != 0) && (val != 1)) {
1182                         err = -EINVAL;
1183                         break;
1184                 }
1185                 session->recv_seq = !!val;
1186                 l2tp_info(session, L2TP_MSG_CONTROL,
1187                           "%s: set recv_seq=%d\n",
1188                           session->name, session->recv_seq);
1189                 break;
1190 
1191         case PPPOL2TP_SO_SENDSEQ:
1192                 if ((val != 0) && (val != 1)) {
1193                         err = -EINVAL;
1194                         break;
1195                 }
1196                 session->send_seq = !!val;
1197                 {
1198                         struct pppox_sock *po = pppox_sk(sk);
1199 
1200                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1201                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1202                 }
1203                 l2tp_session_set_header_len(session, session->tunnel->version);
1204                 l2tp_info(session, L2TP_MSG_CONTROL,
1205                           "%s: set send_seq=%d\n",
1206                           session->name, session->send_seq);
1207                 break;
1208 
1209         case PPPOL2TP_SO_LNSMODE:
1210                 if ((val != 0) && (val != 1)) {
1211                         err = -EINVAL;
1212                         break;
1213                 }
1214                 session->lns_mode = !!val;
1215                 l2tp_info(session, L2TP_MSG_CONTROL,
1216                           "%s: set lns_mode=%d\n",
1217                           session->name, session->lns_mode);
1218                 break;
1219 
1220         case PPPOL2TP_SO_DEBUG:
1221                 session->debug = val;
1222                 l2tp_info(session, L2TP_MSG_CONTROL, "%s: set debug=%x\n",
1223                           session->name, session->debug);
1224                 break;
1225 
1226         case PPPOL2TP_SO_REORDERTO:
1227                 session->reorder_timeout = msecs_to_jiffies(val);
1228                 l2tp_info(session, L2TP_MSG_CONTROL,
1229                           "%s: set reorder_timeout=%d\n",
1230                           session->name, session->reorder_timeout);
1231                 break;
1232 
1233         default:
1234                 err = -ENOPROTOOPT;
1235                 break;
1236         }
1237 
1238         return err;
1239 }
1240 
1241 /* Main setsockopt() entry point.
1242  * Does API checks, then calls either the tunnel or session setsockopt
1243  * handler, according to whether the PPPoL2TP socket is a for a regular
1244  * session or the special tunnel type.
1245  */
1246 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1247                                char __user *optval, unsigned int optlen)
1248 {
1249         struct sock *sk = sock->sk;
1250         struct l2tp_session *session;
1251         struct l2tp_tunnel *tunnel;
1252         int val;
1253         int err;
1254 
1255         if (level != SOL_PPPOL2TP)
1256                 return -EINVAL;
1257 
1258         if (optlen < sizeof(int))
1259                 return -EINVAL;
1260 
1261         if (get_user(val, (int __user *)optval))
1262                 return -EFAULT;
1263 
1264         err = -ENOTCONN;
1265         if (sk->sk_user_data == NULL)
1266                 goto end;
1267 
1268         /* Get session context from the socket */
1269         err = -EBADF;
1270         session = pppol2tp_sock_to_session(sk);
1271         if (session == NULL)
1272                 goto end;
1273 
1274         /* Special case: if session_id == 0x0000, treat as operation on tunnel
1275          */
1276         if ((session->session_id == 0) &&
1277             (session->peer_session_id == 0)) {
1278                 tunnel = session->tunnel;
1279                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1280         } else {
1281                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1282         }
1283 
1284         sock_put(sk);
1285 end:
1286         return err;
1287 }
1288 
1289 /* Tunnel getsockopt helper. Called with sock locked.
1290  */
1291 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1292                                       struct l2tp_tunnel *tunnel,
1293                                       int optname, int *val)
1294 {
1295         int err = 0;
1296 
1297         switch (optname) {
1298         case PPPOL2TP_SO_DEBUG:
1299                 *val = tunnel->debug;
1300                 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: get debug=%x\n",
1301                           tunnel->name, tunnel->debug);
1302                 break;
1303 
1304         default:
1305                 err = -ENOPROTOOPT;
1306                 break;
1307         }
1308 
1309         return err;
1310 }
1311 
1312 /* Session getsockopt helper. Called with sock locked.
1313  */
1314 static int pppol2tp_session_getsockopt(struct sock *sk,
1315                                        struct l2tp_session *session,
1316                                        int optname, int *val)
1317 {
1318         int err = 0;
1319 
1320         switch (optname) {
1321         case PPPOL2TP_SO_RECVSEQ:
1322                 *val = session->recv_seq;
1323                 l2tp_info(session, L2TP_MSG_CONTROL,
1324                           "%s: get recv_seq=%d\n", session->name, *val);
1325                 break;
1326 
1327         case PPPOL2TP_SO_SENDSEQ:
1328                 *val = session->send_seq;
1329                 l2tp_info(session, L2TP_MSG_CONTROL,
1330                           "%s: get send_seq=%d\n", session->name, *val);
1331                 break;
1332 
1333         case PPPOL2TP_SO_LNSMODE:
1334                 *val = session->lns_mode;
1335                 l2tp_info(session, L2TP_MSG_CONTROL,
1336                           "%s: get lns_mode=%d\n", session->name, *val);
1337                 break;
1338 
1339         case PPPOL2TP_SO_DEBUG:
1340                 *val = session->debug;
1341                 l2tp_info(session, L2TP_MSG_CONTROL, "%s: get debug=%d\n",
1342                           session->name, *val);
1343                 break;
1344 
1345         case PPPOL2TP_SO_REORDERTO:
1346                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
1347                 l2tp_info(session, L2TP_MSG_CONTROL,
1348                           "%s: get reorder_timeout=%d\n", session->name, *val);
1349                 break;
1350 
1351         default:
1352                 err = -ENOPROTOOPT;
1353         }
1354 
1355         return err;
1356 }
1357 
1358 /* Main getsockopt() entry point.
1359  * Does API checks, then calls either the tunnel or session getsockopt
1360  * handler, according to whether the PPPoX socket is a for a regular session
1361  * or the special tunnel type.
1362  */
1363 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1364                                char __user *optval, int __user *optlen)
1365 {
1366         struct sock *sk = sock->sk;
1367         struct l2tp_session *session;
1368         struct l2tp_tunnel *tunnel;
1369         int val, len;
1370         int err;
1371 
1372         if (level != SOL_PPPOL2TP)
1373                 return -EINVAL;
1374 
1375         if (get_user(len, optlen))
1376                 return -EFAULT;
1377 
1378         len = min_t(unsigned int, len, sizeof(int));
1379 
1380         if (len < 0)
1381                 return -EINVAL;
1382 
1383         err = -ENOTCONN;
1384         if (sk->sk_user_data == NULL)
1385                 goto end;
1386 
1387         /* Get the session context */
1388         err = -EBADF;
1389         session = pppol2tp_sock_to_session(sk);
1390         if (session == NULL)
1391                 goto end;
1392 
1393         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1394         if ((session->session_id == 0) &&
1395             (session->peer_session_id == 0)) {
1396                 tunnel = session->tunnel;
1397                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1398                 if (err)
1399                         goto end_put_sess;
1400         } else {
1401                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1402                 if (err)
1403                         goto end_put_sess;
1404         }
1405 
1406         err = -EFAULT;
1407         if (put_user(len, optlen))
1408                 goto end_put_sess;
1409 
1410         if (copy_to_user((void __user *) optval, &val, len))
1411                 goto end_put_sess;
1412 
1413         err = 0;
1414 
1415 end_put_sess:
1416         sock_put(sk);
1417 end:
1418         return err;
1419 }
1420 
1421 /*****************************************************************************
1422  * /proc filesystem for debug
1423  * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1424  * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1425  *****************************************************************************/
1426 
1427 static unsigned int pppol2tp_net_id;
1428 
1429 #ifdef CONFIG_PROC_FS
1430 
1431 struct pppol2tp_seq_data {
1432         struct seq_net_private p;
1433         int tunnel_idx;                 /* current tunnel */
1434         int session_idx;                /* index of session within current tunnel */
1435         struct l2tp_tunnel *tunnel;
1436         struct l2tp_session *session;   /* NULL means get next tunnel */
1437 };
1438 
1439 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1440 {
1441         /* Drop reference taken during previous invocation */
1442         if (pd->tunnel)
1443                 l2tp_tunnel_dec_refcount(pd->tunnel);
1444 
1445         for (;;) {
1446                 pd->tunnel = l2tp_tunnel_get_nth(net, pd->tunnel_idx);
1447                 pd->tunnel_idx++;
1448 
1449                 /* Only accept L2TPv2 tunnels */
1450                 if (!pd->tunnel || pd->tunnel->version == 2)
1451                         return;
1452 
1453                 l2tp_tunnel_dec_refcount(pd->tunnel);
1454         }
1455 }
1456 
1457 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1458 {
1459         /* Drop reference taken during previous invocation */
1460         if (pd->session)
1461                 l2tp_session_dec_refcount(pd->session);
1462 
1463         pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
1464         pd->session_idx++;
1465 
1466         if (pd->session == NULL) {
1467                 pd->session_idx = 0;
1468                 pppol2tp_next_tunnel(net, pd);
1469         }
1470 }
1471 
1472 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1473 {
1474         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1475         loff_t pos = *offs;
1476         struct net *net;
1477 
1478         if (!pos)
1479                 goto out;
1480 
1481         BUG_ON(m->private == NULL);
1482         pd = m->private;
1483         net = seq_file_net(m);
1484 
1485         if (pd->tunnel == NULL)
1486                 pppol2tp_next_tunnel(net, pd);
1487         else
1488                 pppol2tp_next_session(net, pd);
1489 
1490         /* NULL tunnel and session indicates end of list */
1491         if ((pd->tunnel == NULL) && (pd->session == NULL))
1492                 pd = NULL;
1493 
1494 out:
1495         return pd;
1496 }
1497 
1498 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1499 {
1500         (*pos)++;
1501         return NULL;
1502 }
1503 
1504 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1505 {
1506         struct pppol2tp_seq_data *pd = v;
1507 
1508         if (!pd || pd == SEQ_START_TOKEN)
1509                 return;
1510 
1511         /* Drop reference taken by last invocation of pppol2tp_next_session()
1512          * or pppol2tp_next_tunnel().
1513          */
1514         if (pd->session) {
1515                 l2tp_session_dec_refcount(pd->session);
1516                 pd->session = NULL;
1517         }
1518         if (pd->tunnel) {
1519                 l2tp_tunnel_dec_refcount(pd->tunnel);
1520                 pd->tunnel = NULL;
1521         }
1522 }
1523 
1524 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1525 {
1526         struct l2tp_tunnel *tunnel = v;
1527 
1528         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1529                    tunnel->name,
1530                    (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
1531                    refcount_read(&tunnel->ref_count) - 1);
1532         seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1533                    tunnel->debug,
1534                    atomic_long_read(&tunnel->stats.tx_packets),
1535                    atomic_long_read(&tunnel->stats.tx_bytes),
1536                    atomic_long_read(&tunnel->stats.tx_errors),
1537                    atomic_long_read(&tunnel->stats.rx_packets),
1538                    atomic_long_read(&tunnel->stats.rx_bytes),
1539                    atomic_long_read(&tunnel->stats.rx_errors));
1540 }
1541 
1542 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1543 {
1544         struct l2tp_session *session = v;
1545         struct l2tp_tunnel *tunnel = session->tunnel;
1546         unsigned char state;
1547         char user_data_ok;
1548         struct sock *sk;
1549         u32 ip = 0;
1550         u16 port = 0;
1551 
1552         if (tunnel->sock) {
1553                 struct inet_sock *inet = inet_sk(tunnel->sock);
1554                 ip = ntohl(inet->inet_saddr);
1555                 port = ntohs(inet->inet_sport);
1556         }
1557 
1558         sk = pppol2tp_session_get_sock(session);
1559         if (sk) {
1560                 state = sk->sk_state;
1561                 user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
1562         } else {
1563                 state = 0;
1564                 user_data_ok = 'N';
1565         }
1566 
1567         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
1568                    "%04X/%04X %d %c\n",
1569                    session->name, ip, port,
1570                    tunnel->tunnel_id,
1571                    session->session_id,
1572                    tunnel->peer_tunnel_id,
1573                    session->peer_session_id,
1574                    state, user_data_ok);
1575         seq_printf(m, "   0/0/%c/%c/%s %08x %u\n",
1576                    session->recv_seq ? 'R' : '-',
1577                    session->send_seq ? 'S' : '-',
1578                    session->lns_mode ? "LNS" : "LAC",
1579                    session->debug,
1580                    jiffies_to_msecs(session->reorder_timeout));
1581         seq_printf(m, "   %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n",
1582                    session->nr, session->ns,
1583                    atomic_long_read(&session->stats.tx_packets),
1584                    atomic_long_read(&session->stats.tx_bytes),
1585                    atomic_long_read(&session->stats.tx_errors),
1586                    atomic_long_read(&session->stats.rx_packets),
1587                    atomic_long_read(&session->stats.rx_bytes),
1588                    atomic_long_read(&session->stats.rx_errors));
1589 
1590         if (sk) {
1591                 struct pppox_sock *po = pppox_sk(sk);
1592 
1593                 seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
1594                 sock_put(sk);
1595         }
1596 }
1597 
1598 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1599 {
1600         struct pppol2tp_seq_data *pd = v;
1601 
1602         /* display header on line 1 */
1603         if (v == SEQ_START_TOKEN) {
1604                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1605                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1606                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1607                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
1608                          "dest-tid/sid state user-data-ok\n");
1609                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1610                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1611                 goto out;
1612         }
1613 
1614         if (!pd->session)
1615                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1616         else
1617                 pppol2tp_seq_session_show(m, pd->session);
1618 
1619 out:
1620         return 0;
1621 }
1622 
1623 static const struct seq_operations pppol2tp_seq_ops = {
1624         .start          = pppol2tp_seq_start,
1625         .next           = pppol2tp_seq_next,
1626         .stop           = pppol2tp_seq_stop,
1627         .show           = pppol2tp_seq_show,
1628 };
1629 #endif /* CONFIG_PROC_FS */
1630 
1631 /*****************************************************************************
1632  * Network namespace
1633  *****************************************************************************/
1634 
1635 static __net_init int pppol2tp_init_net(struct net *net)
1636 {
1637         struct proc_dir_entry *pde;
1638         int err = 0;
1639 
1640         pde = proc_create_net("pppol2tp", 0444, net->proc_net,
1641                         &pppol2tp_seq_ops, sizeof(struct pppol2tp_seq_data));
1642         if (!pde) {
1643                 err = -ENOMEM;
1644                 goto out;
1645         }
1646 
1647 out:
1648         return err;
1649 }
1650 
1651 static __net_exit void pppol2tp_exit_net(struct net *net)
1652 {
1653         remove_proc_entry("pppol2tp", net->proc_net);
1654 }
1655 
1656 static struct pernet_operations pppol2tp_net_ops = {
1657         .init = pppol2tp_init_net,
1658         .exit = pppol2tp_exit_net,
1659         .id   = &pppol2tp_net_id,
1660 };
1661 
1662 /*****************************************************************************
1663  * Init and cleanup
1664  *****************************************************************************/
1665 
1666 static const struct proto_ops pppol2tp_ops = {
1667         .family         = AF_PPPOX,
1668         .owner          = THIS_MODULE,
1669         .release        = pppol2tp_release,
1670         .bind           = sock_no_bind,
1671         .connect        = pppol2tp_connect,
1672         .socketpair     = sock_no_socketpair,
1673         .accept         = sock_no_accept,
1674         .getname        = pppol2tp_getname,
1675         .poll           = datagram_poll,
1676         .listen         = sock_no_listen,
1677         .shutdown       = sock_no_shutdown,
1678         .setsockopt     = pppol2tp_setsockopt,
1679         .getsockopt     = pppol2tp_getsockopt,
1680         .sendmsg        = pppol2tp_sendmsg,
1681         .recvmsg        = pppol2tp_recvmsg,
1682         .mmap           = sock_no_mmap,
1683         .ioctl          = pppox_ioctl,
1684 #ifdef CONFIG_COMPAT
1685         .compat_ioctl = pppox_compat_ioctl,
1686 #endif
1687 };
1688 
1689 static const struct pppox_proto pppol2tp_proto = {
1690         .create         = pppol2tp_create,
1691         .ioctl          = pppol2tp_ioctl,
1692         .owner          = THIS_MODULE,
1693 };
1694 
1695 #ifdef CONFIG_L2TP_V3
1696 
1697 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1698         .session_create = pppol2tp_session_create,
1699         .session_delete = l2tp_session_delete,
1700 };
1701 
1702 #endif /* CONFIG_L2TP_V3 */
1703 
1704 static int __init pppol2tp_init(void)
1705 {
1706         int err;
1707 
1708         err = register_pernet_device(&pppol2tp_net_ops);
1709         if (err)
1710                 goto out;
1711 
1712         err = proto_register(&pppol2tp_sk_proto, 0);
1713         if (err)
1714                 goto out_unregister_pppol2tp_pernet;
1715 
1716         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1717         if (err)
1718                 goto out_unregister_pppol2tp_proto;
1719 
1720 #ifdef CONFIG_L2TP_V3
1721         err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1722         if (err)
1723                 goto out_unregister_pppox;
1724 #endif
1725 
1726         pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1727 
1728 out:
1729         return err;
1730 
1731 #ifdef CONFIG_L2TP_V3
1732 out_unregister_pppox:
1733         unregister_pppox_proto(PX_PROTO_OL2TP);
1734 #endif
1735 out_unregister_pppol2tp_proto:
1736         proto_unregister(&pppol2tp_sk_proto);
1737 out_unregister_pppol2tp_pernet:
1738         unregister_pernet_device(&pppol2tp_net_ops);
1739         goto out;
1740 }
1741 
1742 static void __exit pppol2tp_exit(void)
1743 {
1744 #ifdef CONFIG_L2TP_V3
1745         l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1746 #endif
1747         unregister_pppox_proto(PX_PROTO_OL2TP);
1748         proto_unregister(&pppol2tp_sk_proto);
1749         unregister_pernet_device(&pppol2tp_net_ops);
1750 }
1751 
1752 module_init(pppol2tp_init);
1753 module_exit(pppol2tp_exit);
1754 
1755 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1756 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1757 MODULE_LICENSE("GPL");
1758 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1759 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1760 MODULE_ALIAS_L2TP_PWTYPE(7);
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root/net/l2tp/l2tp_ppp.c

DEFINITIONS
