linux/net/l2tp/l2tp_ip6.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * L2TPv3 IP encapsulation support for IPv6
   4 *
   5 * Copyright (c) 2012 Katalix Systems Ltd
   6 */
   7
   8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10#include <linux/icmp.h>
  11#include <linux/module.h>
  12#include <linux/skbuff.h>
  13#include <linux/random.h>
  14#include <linux/socket.h>
  15#include <linux/l2tp.h>
  16#include <linux/in.h>
  17#include <linux/in6.h>
  18#include <net/sock.h>
  19#include <net/ip.h>
  20#include <net/icmp.h>
  21#include <net/udp.h>
  22#include <net/inet_common.h>
  23#include <net/inet_hashtables.h>
  24#include <net/inet6_hashtables.h>
  25#include <net/tcp_states.h>
  26#include <net/protocol.h>
  27#include <net/xfrm.h>
  28
  29#include <net/transp_v6.h>
  30#include <net/addrconf.h>
  31#include <net/ip6_route.h>
  32
  33#include "l2tp_core.h"
  34
  35struct l2tp_ip6_sock {
  36        /* inet_sock has to be the first member of l2tp_ip6_sock */
  37        struct inet_sock        inet;
  38
  39        u32                     conn_id;
  40        u32                     peer_conn_id;
  41
  42        /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
  43           inet6_sk_generic */
  44        struct ipv6_pinfo       inet6;
  45};
  46
  47static DEFINE_RWLOCK(l2tp_ip6_lock);
  48static struct hlist_head l2tp_ip6_table;
  49static struct hlist_head l2tp_ip6_bind_table;
  50
  51static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
  52{
  53        return (struct l2tp_ip6_sock *)sk;
  54}
  55
  56static struct sock *__l2tp_ip6_bind_lookup(const struct net *net,
  57                                           const struct in6_addr *laddr,
  58                                           const struct in6_addr *raddr,
  59                                           int dif, u32 tunnel_id)
  60{
  61        struct sock *sk;
  62
  63        sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
  64                const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
  65                const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
  66                const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
  67
  68                if (!net_eq(sock_net(sk), net))
  69                        continue;
  70
  71                if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
  72                        continue;
  73
  74                if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
  75                    !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
  76                        continue;
  77
  78                if (!ipv6_addr_any(sk_raddr) && raddr &&
  79                    !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
  80                        continue;
  81
  82                if (l2tp->conn_id != tunnel_id)
  83                        continue;
  84
  85                goto found;
  86        }
  87
  88        sk = NULL;
  89found:
  90        return sk;
  91}
  92
  93/* When processing receive frames, there are two cases to
  94 * consider. Data frames consist of a non-zero session-id and an
  95 * optional cookie. Control frames consist of a regular L2TP header
  96 * preceded by 32-bits of zeros.
  97 *
  98 * L2TPv3 Session Header Over IP
  99 *
 100 *  0                   1                   2                   3
 101 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 103 * |                           Session ID                          |
 104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 105 * |               Cookie (optional, maximum 64 bits)...
 106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107 *                                                                 |
 108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 109 *
 110 * L2TPv3 Control Message Header Over IP
 111 *
 112 *  0                   1                   2                   3
 113 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 114 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 115 * |                      (32 bits of zeros)                       |
 116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 117 * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 119 * |                     Control Connection ID                     |
 120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 121 * |               Ns              |               Nr              |
 122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 123 *
 124 * All control frames are passed to userspace.
 125 */
 126static int l2tp_ip6_recv(struct sk_buff *skb)
 127{
 128        struct net *net = dev_net(skb->dev);
 129        struct sock *sk;
 130        u32 session_id;
 131        u32 tunnel_id;
 132        unsigned char *ptr, *optr;
 133        struct l2tp_session *session;
 134        struct l2tp_tunnel *tunnel = NULL;
 135        struct ipv6hdr *iph;
 136        int length;
 137
 138        if (!pskb_may_pull(skb, 4))
 139                goto discard;
 140
 141        /* Point to L2TP header */
 142        optr = ptr = skb->data;
 143        session_id = ntohl(*((__be32 *) ptr));
 144        ptr += 4;
 145
 146        /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 147         * the session_id. If it is 0, the packet is a L2TP control
 148         * frame and the session_id value can be discarded.
 149         */
 150        if (session_id == 0) {
 151                __skb_pull(skb, 4);
 152                goto pass_up;
 153        }
 154
 155        /* Ok, this is a data packet. Lookup the session. */
 156        session = l2tp_session_get(net, session_id);
 157        if (!session)
 158                goto discard;
 159
 160        tunnel = session->tunnel;
 161        if (!tunnel)
 162                goto discard_sess;
 163
 164        /* Trace packet contents, if enabled */
 165        if (tunnel->debug & L2TP_MSG_DATA) {
 166                length = min(32u, skb->len);
 167                if (!pskb_may_pull(skb, length))
 168                        goto discard_sess;
 169
 170                /* Point to L2TP header */
 171                optr = ptr = skb->data;
 172                ptr += 4;
 173                pr_debug("%s: ip recv\n", tunnel->name);
 174                print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 175        }
 176
 177        if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
 178                goto discard_sess;
 179
 180        l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
 181        l2tp_session_dec_refcount(session);
 182
 183        return 0;
 184
 185pass_up:
 186        /* Get the tunnel_id from the L2TP header */
 187        if (!pskb_may_pull(skb, 12))
 188                goto discard;
 189
 190        if ((skb->data[0] & 0xc0) != 0xc0)
 191                goto discard;
 192
 193        tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 194        iph = ipv6_hdr(skb);
 195
 196        read_lock_bh(&l2tp_ip6_lock);
 197        sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
 198                                    inet6_iif(skb), tunnel_id);
 199        if (!sk) {
 200                read_unlock_bh(&l2tp_ip6_lock);
 201                goto discard;
 202        }
 203        sock_hold(sk);
 204        read_unlock_bh(&l2tp_ip6_lock);
 205
 206        if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 207                goto discard_put;
 208
 209        nf_reset(skb);
 210
 211        return sk_receive_skb(sk, skb, 1);
 212
 213discard_sess:
 214        l2tp_session_dec_refcount(session);
 215        goto discard;
 216
 217discard_put:
 218        sock_put(sk);
 219
 220discard:
 221        kfree_skb(skb);
 222        return 0;
 223}
 224
 225static int l2tp_ip6_open(struct sock *sk)
 226{
 227        /* Prevent autobind. We don't have ports. */
 228        inet_sk(sk)->inet_num = IPPROTO_L2TP;
 229
 230        write_lock_bh(&l2tp_ip6_lock);
 231        sk_add_node(sk, &l2tp_ip6_table);
 232        write_unlock_bh(&l2tp_ip6_lock);
 233
 234        return 0;
 235}
 236
 237static void l2tp_ip6_close(struct sock *sk, long timeout)
 238{
 239        write_lock_bh(&l2tp_ip6_lock);
 240        hlist_del_init(&sk->sk_bind_node);
 241        sk_del_node_init(sk);
 242        write_unlock_bh(&l2tp_ip6_lock);
 243
 244        sk_common_release(sk);
 245}
 246
 247static void l2tp_ip6_destroy_sock(struct sock *sk)
 248{
 249        struct l2tp_tunnel *tunnel = sk->sk_user_data;
 250
 251        lock_sock(sk);
 252        ip6_flush_pending_frames(sk);
 253        release_sock(sk);
 254
 255        if (tunnel)
 256                l2tp_tunnel_delete(tunnel);
 257
 258        inet6_destroy_sock(sk);
 259}
 260
 261static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 262{
 263        struct inet_sock *inet = inet_sk(sk);
 264        struct ipv6_pinfo *np = inet6_sk(sk);
 265        struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 266        struct net *net = sock_net(sk);
 267        __be32 v4addr = 0;
 268        int bound_dev_if;
 269        int addr_type;
 270        int err;
 271
 272        if (addr->l2tp_family != AF_INET6)
 273                return -EINVAL;
 274        if (addr_len < sizeof(*addr))
 275                return -EINVAL;
 276
 277        addr_type = ipv6_addr_type(&addr->l2tp_addr);
 278
 279        /* l2tp_ip6 sockets are IPv6 only */
 280        if (addr_type == IPV6_ADDR_MAPPED)
 281                return -EADDRNOTAVAIL;
 282
 283        /* L2TP is point-point, not multicast */
 284        if (addr_type & IPV6_ADDR_MULTICAST)
 285                return -EADDRNOTAVAIL;
 286
 287        lock_sock(sk);
 288
 289        err = -EINVAL;
 290        if (!sock_flag(sk, SOCK_ZAPPED))
 291                goto out_unlock;
 292
 293        if (sk->sk_state != TCP_CLOSE)
 294                goto out_unlock;
 295
 296        bound_dev_if = sk->sk_bound_dev_if;
 297
 298        /* Check if the address belongs to the host. */
 299        rcu_read_lock();
 300        if (addr_type != IPV6_ADDR_ANY) {
 301                struct net_device *dev = NULL;
 302
 303                if (addr_type & IPV6_ADDR_LINKLOCAL) {
 304                        if (addr->l2tp_scope_id)
 305                                bound_dev_if = addr->l2tp_scope_id;
 306
 307                        /* Binding to link-local address requires an
 308                         * interface.
 309                         */
 310                        if (!bound_dev_if)
 311                                goto out_unlock_rcu;
 312
 313                        err = -ENODEV;
 314                        dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
 315                        if (!dev)
 316                                goto out_unlock_rcu;
 317                }
 318
 319                /* ipv4 addr of the socket is invalid.  Only the
 320                 * unspecified and mapped address have a v4 equivalent.
 321                 */
 322                v4addr = LOOPBACK4_IPV6;
 323                err = -EADDRNOTAVAIL;
 324                if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 325                        goto out_unlock_rcu;
 326        }
 327        rcu_read_unlock();
 328
 329        write_lock_bh(&l2tp_ip6_lock);
 330        if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
 331                                   addr->l2tp_conn_id)) {
 332                write_unlock_bh(&l2tp_ip6_lock);
 333                err = -EADDRINUSE;
 334                goto out_unlock;
 335        }
 336
 337        inet->inet_saddr = v4addr;
 338        inet->inet_rcv_saddr = v4addr;
 339        sk->sk_bound_dev_if = bound_dev_if;
 340        sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 341        np->saddr = addr->l2tp_addr;
 342
 343        l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 344
 345        sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 346        sk_del_node_init(sk);
 347        write_unlock_bh(&l2tp_ip6_lock);
 348
 349        sock_reset_flag(sk, SOCK_ZAPPED);
 350        release_sock(sk);
 351        return 0;
 352
 353out_unlock_rcu:
 354        rcu_read_unlock();
 355out_unlock:
 356        release_sock(sk);
 357
 358        return err;
 359}
 360
 361static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 362                            int addr_len)
 363{
 364        struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 365        struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 366        struct in6_addr *daddr;
 367        int     addr_type;
 368        int rc;
 369
 370        if (addr_len < sizeof(*lsa))
 371                return -EINVAL;
 372
 373        if (usin->sin6_family != AF_INET6)
 374                return -EINVAL;
 375
 376        addr_type = ipv6_addr_type(&usin->sin6_addr);
 377        if (addr_type & IPV6_ADDR_MULTICAST)
 378                return -EINVAL;
 379
 380        if (addr_type & IPV6_ADDR_MAPPED) {
 381                daddr = &usin->sin6_addr;
 382                if (ipv4_is_multicast(daddr->s6_addr32[3]))
 383                        return -EINVAL;
 384        }
 385
 386        lock_sock(sk);
 387
 388         /* Must bind first - autobinding does not work */
 389        if (sock_flag(sk, SOCK_ZAPPED)) {
 390                rc = -EINVAL;
 391                goto out_sk;
 392        }
 393
 394        rc = __ip6_datagram_connect(sk, uaddr, addr_len);
 395        if (rc < 0)
 396                goto out_sk;
 397
 398        l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 399
 400        write_lock_bh(&l2tp_ip6_lock);
 401        hlist_del_init(&sk->sk_bind_node);
 402        sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 403        write_unlock_bh(&l2tp_ip6_lock);
 404
 405out_sk:
 406        release_sock(sk);
 407
 408        return rc;
 409}
 410
 411static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 412{
 413        if (sock_flag(sk, SOCK_ZAPPED))
 414                return 0;
 415
 416        return __udp_disconnect(sk, flags);
 417}
 418
 419static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 420                            int peer)
 421{
 422        struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 423        struct sock *sk = sock->sk;
 424        struct ipv6_pinfo *np = inet6_sk(sk);
 425        struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 426
 427        lsa->l2tp_family = AF_INET6;
 428        lsa->l2tp_flowinfo = 0;
 429        lsa->l2tp_scope_id = 0;
 430        lsa->l2tp_unused = 0;
 431        if (peer) {
 432                if (!lsk->peer_conn_id)
 433                        return -ENOTCONN;
 434                lsa->l2tp_conn_id = lsk->peer_conn_id;
 435                lsa->l2tp_addr = sk->sk_v6_daddr;
 436                if (np->sndflow)
 437                        lsa->l2tp_flowinfo = np->flow_label;
 438        } else {
 439                if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 440                        lsa->l2tp_addr = np->saddr;
 441                else
 442                        lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 443
 444                lsa->l2tp_conn_id = lsk->conn_id;
 445        }
 446        if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 447                lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 448        return sizeof(*lsa);
 449}
 450
 451static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 452{
 453        int rc;
 454
 455        /* Charge it to the socket, dropping if the queue is full. */
 456        rc = sock_queue_rcv_skb(sk, skb);
 457        if (rc < 0)
 458                goto drop;
 459
 460        return 0;
 461
 462drop:
 463        IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 464        kfree_skb(skb);
 465        return -1;
 466}
 467
 468static int l2tp_ip6_push_pending_frames(struct sock *sk)
 469{
 470        struct sk_buff *skb;
 471        __be32 *transhdr = NULL;
 472        int err = 0;
 473
 474        skb = skb_peek(&sk->sk_write_queue);
 475        if (skb == NULL)
 476                goto out;
 477
 478        transhdr = (__be32 *)skb_transport_header(skb);
 479        *transhdr = 0;
 480
 481        err = ip6_push_pending_frames(sk);
 482
 483out:
 484        return err;
 485}
 486
 487/* Userspace will call sendmsg() on the tunnel socket to send L2TP
 488 * control frames.
 489 */
 490static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 491{
 492        struct ipv6_txoptions opt_space;
 493        DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 494        struct in6_addr *daddr, *final_p, final;
 495        struct ipv6_pinfo *np = inet6_sk(sk);
 496        struct ipv6_txoptions *opt_to_free = NULL;
 497        struct ipv6_txoptions *opt = NULL;
 498        struct ip6_flowlabel *flowlabel = NULL;
 499        struct dst_entry *dst = NULL;
 500        struct flowi6 fl6;
 501        struct ipcm6_cookie ipc6;
 502        int addr_len = msg->msg_namelen;
 503        int transhdrlen = 4; /* zero session-id */
 504        int ulen = len + transhdrlen;
 505        int err;
 506
 507        /* Rough check on arithmetic overflow,
 508           better check is made in ip6_append_data().
 509         */
 510        if (len > INT_MAX)
 511                return -EMSGSIZE;
 512
 513        /* Mirror BSD error message compatibility */
 514        if (msg->msg_flags & MSG_OOB)
 515                return -EOPNOTSUPP;
 516
 517        /*
 518         *      Get and verify the address.
 519         */
 520        memset(&fl6, 0, sizeof(fl6));
 521
 522        fl6.flowi6_mark = sk->sk_mark;
 523        fl6.flowi6_uid = sk->sk_uid;
 524
 525        ipcm6_init(&ipc6);
 526
 527        if (lsa) {
 528                if (addr_len < SIN6_LEN_RFC2133)
 529                        return -EINVAL;
 530
 531                if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 532                        return -EAFNOSUPPORT;
 533
 534                daddr = &lsa->l2tp_addr;
 535                if (np->sndflow) {
 536                        fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 537                        if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 538                                flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 539                                if (flowlabel == NULL)
 540                                        return -EINVAL;
 541                        }
 542                }
 543
 544                /*
 545                 * Otherwise it will be difficult to maintain
 546                 * sk->sk_dst_cache.
 547                 */
 548                if (sk->sk_state == TCP_ESTABLISHED &&
 549                    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 550                        daddr = &sk->sk_v6_daddr;
 551
 552                if (addr_len >= sizeof(struct sockaddr_in6) &&
 553                    lsa->l2tp_scope_id &&
 554                    ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 555                        fl6.flowi6_oif = lsa->l2tp_scope_id;
 556        } else {
 557                if (sk->sk_state != TCP_ESTABLISHED)
 558                        return -EDESTADDRREQ;
 559
 560                daddr = &sk->sk_v6_daddr;
 561                fl6.flowlabel = np->flow_label;
 562        }
 563
 564        if (fl6.flowi6_oif == 0)
 565                fl6.flowi6_oif = sk->sk_bound_dev_if;
 566
 567        if (msg->msg_controllen) {
 568                opt = &opt_space;
 569                memset(opt, 0, sizeof(struct ipv6_txoptions));
 570                opt->tot_len = sizeof(struct ipv6_txoptions);
 571                ipc6.opt = opt;
 572
 573                err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
 574                if (err < 0) {
 575                        fl6_sock_release(flowlabel);
 576                        return err;
 577                }
 578                if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 579                        flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 580                        if (flowlabel == NULL)
 581                                return -EINVAL;
 582                }
 583                if (!(opt->opt_nflen|opt->opt_flen))
 584                        opt = NULL;
 585        }
 586
 587        if (!opt) {
 588                opt = txopt_get(np);
 589                opt_to_free = opt;
 590        }
 591        if (flowlabel)
 592                opt = fl6_merge_options(&opt_space, flowlabel, opt);
 593        opt = ipv6_fixup_options(&opt_space, opt);
 594        ipc6.opt = opt;
 595
 596        fl6.flowi6_proto = sk->sk_protocol;
 597        if (!ipv6_addr_any(daddr))
 598                fl6.daddr = *daddr;
 599        else
 600                fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 601        if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 602                fl6.saddr = np->saddr;
 603
 604        final_p = fl6_update_dst(&fl6, opt, &final);
 605
 606        if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 607                fl6.flowi6_oif = np->mcast_oif;
 608        else if (!fl6.flowi6_oif)
 609                fl6.flowi6_oif = np->ucast_oif;
 610
 611        security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 612
 613        if (ipc6.tclass < 0)
 614                ipc6.tclass = np->tclass;
 615
 616        fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 617
 618        dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 619        if (IS_ERR(dst)) {
 620                err = PTR_ERR(dst);
 621                goto out;
 622        }
 623
 624        if (ipc6.hlimit < 0)
 625                ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 626
 627        if (ipc6.dontfrag < 0)
 628                ipc6.dontfrag = np->dontfrag;
 629
 630        if (msg->msg_flags & MSG_CONFIRM)
 631                goto do_confirm;
 632
 633back_from_confirm:
 634        lock_sock(sk);
 635        err = ip6_append_data(sk, ip_generic_getfrag, msg,
 636                              ulen, transhdrlen, &ipc6,
 637                              &fl6, (struct rt6_info *)dst,
 638                              msg->msg_flags);
 639        if (err)
 640                ip6_flush_pending_frames(sk);
 641        else if (!(msg->msg_flags & MSG_MORE))
 642                err = l2tp_ip6_push_pending_frames(sk);
 643        release_sock(sk);
 644done:
 645        dst_release(dst);
 646out:
 647        fl6_sock_release(flowlabel);
 648        txopt_put(opt_to_free);
 649
 650        return err < 0 ? err : len;
 651
 652do_confirm:
 653        if (msg->msg_flags & MSG_PROBE)
 654                dst_confirm_neigh(dst, &fl6.daddr);
 655        if (!(msg->msg_flags & MSG_PROBE) || len)
 656                goto back_from_confirm;
 657        err = 0;
 658        goto done;
 659}
 660
 661static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 662                            int noblock, int flags, int *addr_len)
 663{
 664        struct ipv6_pinfo *np = inet6_sk(sk);
 665        DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 666        size_t copied = 0;
 667        int err = -EOPNOTSUPP;
 668        struct sk_buff *skb;
 669
 670        if (flags & MSG_OOB)
 671                goto out;
 672
 673        if (flags & MSG_ERRQUEUE)
 674                return ipv6_recv_error(sk, msg, len, addr_len);
 675
 676        skb = skb_recv_datagram(sk, flags, noblock, &err);
 677        if (!skb)
 678                goto out;
 679
 680        copied = skb->len;
 681        if (len < copied) {
 682                msg->msg_flags |= MSG_TRUNC;
 683                copied = len;
 684        }
 685
 686        err = skb_copy_datagram_msg(skb, 0, msg, copied);
 687        if (err)
 688                goto done;
 689
 690        sock_recv_timestamp(msg, sk, skb);
 691
 692        /* Copy the address. */
 693        if (lsa) {
 694                lsa->l2tp_family = AF_INET6;
 695                lsa->l2tp_unused = 0;
 696                lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 697                lsa->l2tp_flowinfo = 0;
 698                lsa->l2tp_scope_id = 0;
 699                lsa->l2tp_conn_id = 0;
 700                if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 701                        lsa->l2tp_scope_id = inet6_iif(skb);
 702                *addr_len = sizeof(*lsa);
 703        }
 704
 705        if (np->rxopt.all)
 706                ip6_datagram_recv_ctl(sk, msg, skb);
 707
 708        if (flags & MSG_TRUNC)
 709                copied = skb->len;
 710done:
 711        skb_free_datagram(sk, skb);
 712out:
 713        return err ? err : copied;
 714}
 715
 716static struct proto l2tp_ip6_prot = {
 717        .name              = "L2TP/IPv6",
 718        .owner             = THIS_MODULE,
 719        .init              = l2tp_ip6_open,
 720        .close             = l2tp_ip6_close,
 721        .bind              = l2tp_ip6_bind,
 722        .connect           = l2tp_ip6_connect,
 723        .disconnect        = l2tp_ip6_disconnect,
 724        .ioctl             = l2tp_ioctl,
 725        .destroy           = l2tp_ip6_destroy_sock,
 726        .setsockopt        = ipv6_setsockopt,
 727        .getsockopt        = ipv6_getsockopt,
 728        .sendmsg           = l2tp_ip6_sendmsg,
 729        .recvmsg           = l2tp_ip6_recvmsg,
 730        .backlog_rcv       = l2tp_ip6_backlog_recv,
 731        .hash              = inet6_hash,
 732        .unhash            = inet_unhash,
 733        .obj_size          = sizeof(struct l2tp_ip6_sock),
 734#ifdef CONFIG_COMPAT
 735        .compat_setsockopt = compat_ipv6_setsockopt,
 736        .compat_getsockopt = compat_ipv6_getsockopt,
 737#endif
 738};
 739
 740static const struct proto_ops l2tp_ip6_ops = {
 741        .family            = PF_INET6,
 742        .owner             = THIS_MODULE,
 743        .release           = inet6_release,
 744        .bind              = inet6_bind,
 745        .connect           = inet_dgram_connect,
 746        .socketpair        = sock_no_socketpair,
 747        .accept            = sock_no_accept,
 748        .getname           = l2tp_ip6_getname,
 749        .poll              = datagram_poll,
 750        .ioctl             = inet6_ioctl,
 751        .gettstamp         = sock_gettstamp,
 752        .listen            = sock_no_listen,
 753        .shutdown          = inet_shutdown,
 754        .setsockopt        = sock_common_setsockopt,
 755        .getsockopt        = sock_common_getsockopt,
 756        .sendmsg           = inet_sendmsg,
 757        .recvmsg           = sock_common_recvmsg,
 758        .mmap              = sock_no_mmap,
 759        .sendpage          = sock_no_sendpage,
 760#ifdef CONFIG_COMPAT
 761        .compat_setsockopt = compat_sock_common_setsockopt,
 762        .compat_getsockopt = compat_sock_common_getsockopt,
 763#endif
 764};
 765
 766static struct inet_protosw l2tp_ip6_protosw = {
 767        .type           = SOCK_DGRAM,
 768        .protocol       = IPPROTO_L2TP,
 769        .prot           = &l2tp_ip6_prot,
 770        .ops            = &l2tp_ip6_ops,
 771};
 772
 773static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 774        .handler        = l2tp_ip6_recv,
 775};
 776
 777static int __init l2tp_ip6_init(void)
 778{
 779        int err;
 780
 781        pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 782
 783        err = proto_register(&l2tp_ip6_prot, 1);
 784        if (err != 0)
 785                goto out;
 786
 787        err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 788        if (err)
 789                goto out1;
 790
 791        inet6_register_protosw(&l2tp_ip6_protosw);
 792        return 0;
 793
 794out1:
 795        proto_unregister(&l2tp_ip6_prot);
 796out:
 797        return err;
 798}
 799
 800static void __exit l2tp_ip6_exit(void)
 801{
 802        inet6_unregister_protosw(&l2tp_ip6_protosw);
 803        inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 804        proto_unregister(&l2tp_ip6_prot);
 805}
 806
 807module_init(l2tp_ip6_init);
 808module_exit(l2tp_ip6_exit);
 809
 810MODULE_LICENSE("GPL");
 811MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 812MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 813MODULE_VERSION("1.0");
 814
 815/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 816 * enums
 817 */
 818MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 819MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
 820