linux/net/l2tp/l2tp_ip6.c
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   1/*
   2 * L2TPv3 IP encapsulation support for IPv6
   3 *
   4 * Copyright (c) 2012 Katalix Systems Ltd
   5 *
   6 *      This program is free software; you can redistribute it and/or
   7 *      modify it under the terms of the GNU General Public License
   8 *      as published by the Free Software Foundation; either version
   9 *      2 of the License, or (at your option) any later version.
  10 */
  11
  12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14#include <linux/icmp.h>
  15#include <linux/module.h>
  16#include <linux/skbuff.h>
  17#include <linux/random.h>
  18#include <linux/socket.h>
  19#include <linux/l2tp.h>
  20#include <linux/in.h>
  21#include <linux/in6.h>
  22#include <net/sock.h>
  23#include <net/ip.h>
  24#include <net/icmp.h>
  25#include <net/udp.h>
  26#include <net/inet_common.h>
  27#include <net/inet_hashtables.h>
  28#include <net/tcp_states.h>
  29#include <net/protocol.h>
  30#include <net/xfrm.h>
  31
  32#include <net/transp_v6.h>
  33#include <net/addrconf.h>
  34#include <net/ip6_route.h>
  35
  36#include "l2tp_core.h"
  37
  38struct l2tp_ip6_sock {
  39        /* inet_sock has to be the first member of l2tp_ip6_sock */
  40        struct inet_sock        inet;
  41
  42        u32                     conn_id;
  43        u32                     peer_conn_id;
  44
  45        /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
  46           inet6_sk_generic */
  47        struct ipv6_pinfo       inet6;
  48};
  49
  50static DEFINE_RWLOCK(l2tp_ip6_lock);
  51static struct hlist_head l2tp_ip6_table;
  52static struct hlist_head l2tp_ip6_bind_table;
  53
  54static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
  55{
  56        return (struct l2tp_ip6_sock *)sk;
  57}
  58
  59static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
  60                                           struct in6_addr *laddr,
  61                                           int dif, u32 tunnel_id)
  62{
  63        struct hlist_node *node;
  64        struct sock *sk;
  65
  66        sk_for_each_bound(sk, node, &l2tp_ip6_bind_table) {
  67                struct in6_addr *addr = inet6_rcv_saddr(sk);
  68                struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
  69
  70                if (l2tp == NULL)
  71                        continue;
  72
  73                if ((l2tp->conn_id == tunnel_id) &&
  74                    net_eq(sock_net(sk), net) &&
  75                    !(addr && ipv6_addr_equal(addr, laddr)) &&
  76                    !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  77                        goto found;
  78        }
  79
  80        sk = NULL;
  81found:
  82        return sk;
  83}
  84
  85static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
  86                                                struct in6_addr *laddr,
  87                                                int dif, u32 tunnel_id)
  88{
  89        struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
  90        if (sk)
  91                sock_hold(sk);
  92
  93        return sk;
  94}
  95
  96/* When processing receive frames, there are two cases to
  97 * consider. Data frames consist of a non-zero session-id and an
  98 * optional cookie. Control frames consist of a regular L2TP header
  99 * preceded by 32-bits of zeros.
 100 *
 101 * L2TPv3 Session Header Over IP
 102 *
 103 *  0                   1                   2                   3
 104 *  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
 105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106 * |                           Session ID                          |
 107 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108 * |               Cookie (optional, maximum 64 bits)...
 109 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 110 *                                                                 |
 111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 112 *
 113 * L2TPv3 Control Message Header Over IP
 114 *
 115 *  0                   1                   2                   3
 116 *  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
 117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 118 * |                      (32 bits of zeros)                       |
 119 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 120 * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 121 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 122 * |                     Control Connection ID                     |
 123 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 124 * |               Ns              |               Nr              |
 125 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 126 *
 127 * All control frames are passed to userspace.
 128 */
 129static int l2tp_ip6_recv(struct sk_buff *skb)
 130{
 131        struct sock *sk;
 132        u32 session_id;
 133        u32 tunnel_id;
 134        unsigned char *ptr, *optr;
 135        struct l2tp_session *session;
 136        struct l2tp_tunnel *tunnel = NULL;
 137        int length;
 138
 139        /* Point to L2TP header */
 140        optr = ptr = skb->data;
 141
 142        if (!pskb_may_pull(skb, 4))
 143                goto discard;
 144
 145        session_id = ntohl(*((__be32 *) ptr));
 146        ptr += 4;
 147
 148        /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 149         * the session_id. If it is 0, the packet is a L2TP control
 150         * frame and the session_id value can be discarded.
 151         */
 152        if (session_id == 0) {
 153                __skb_pull(skb, 4);
 154                goto pass_up;
 155        }
 156
 157        /* Ok, this is a data packet. Lookup the session. */
 158        session = l2tp_session_find(&init_net, NULL, session_id);
 159        if (session == NULL)
 160                goto discard;
 161
 162        tunnel = session->tunnel;
 163        if (tunnel == NULL)
 164                goto discard;
 165
 166        /* Trace packet contents, if enabled */
 167        if (tunnel->debug & L2TP_MSG_DATA) {
 168                length = min(32u, skb->len);
 169                if (!pskb_may_pull(skb, length))
 170                        goto discard;
 171
 172                pr_debug("%s: ip recv\n", tunnel->name);
 173                print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 174        }
 175
 176        l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 177                         tunnel->recv_payload_hook);
 178        return 0;
 179
 180pass_up:
 181        /* Get the tunnel_id from the L2TP header */
 182        if (!pskb_may_pull(skb, 12))
 183                goto discard;
 184
 185        if ((skb->data[0] & 0xc0) != 0xc0)
 186                goto discard;
 187
 188        tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 189        tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
 190        if (tunnel != NULL)
 191                sk = tunnel->sock;
 192        else {
 193                struct ipv6hdr *iph = ipv6_hdr(skb);
 194
 195                read_lock_bh(&l2tp_ip6_lock);
 196                sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
 197                                            0, tunnel_id);
 198                read_unlock_bh(&l2tp_ip6_lock);
 199        }
 200
 201        if (sk == NULL)
 202                goto discard;
 203
 204        sock_hold(sk);
 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_put:
 214        sock_put(sk);
 215
 216discard:
 217        kfree_skb(skb);
 218        return 0;
 219}
 220
 221static int l2tp_ip6_open(struct sock *sk)
 222{
 223        /* Prevent autobind. We don't have ports. */
 224        inet_sk(sk)->inet_num = IPPROTO_L2TP;
 225
 226        write_lock_bh(&l2tp_ip6_lock);
 227        sk_add_node(sk, &l2tp_ip6_table);
 228        write_unlock_bh(&l2tp_ip6_lock);
 229
 230        return 0;
 231}
 232
 233static void l2tp_ip6_close(struct sock *sk, long timeout)
 234{
 235        write_lock_bh(&l2tp_ip6_lock);
 236        hlist_del_init(&sk->sk_bind_node);
 237        sk_del_node_init(sk);
 238        write_unlock_bh(&l2tp_ip6_lock);
 239
 240        sk_common_release(sk);
 241}
 242
 243static void l2tp_ip6_destroy_sock(struct sock *sk)
 244{
 245        lock_sock(sk);
 246        ip6_flush_pending_frames(sk);
 247        release_sock(sk);
 248
 249        inet6_destroy_sock(sk);
 250}
 251
 252static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 253{
 254        struct inet_sock *inet = inet_sk(sk);
 255        struct ipv6_pinfo *np = inet6_sk(sk);
 256        struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 257        __be32 v4addr = 0;
 258        int addr_type;
 259        int err;
 260
 261        if (!sock_flag(sk, SOCK_ZAPPED))
 262                return -EINVAL;
 263        if (addr->l2tp_family != AF_INET6)
 264                return -EINVAL;
 265        if (addr_len < sizeof(*addr))
 266                return -EINVAL;
 267
 268        addr_type = ipv6_addr_type(&addr->l2tp_addr);
 269
 270        /* l2tp_ip6 sockets are IPv6 only */
 271        if (addr_type == IPV6_ADDR_MAPPED)
 272                return -EADDRNOTAVAIL;
 273
 274        /* L2TP is point-point, not multicast */
 275        if (addr_type & IPV6_ADDR_MULTICAST)
 276                return -EADDRNOTAVAIL;
 277
 278        err = -EADDRINUSE;
 279        read_lock_bh(&l2tp_ip6_lock);
 280        if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
 281                                   sk->sk_bound_dev_if, addr->l2tp_conn_id))
 282                goto out_in_use;
 283        read_unlock_bh(&l2tp_ip6_lock);
 284
 285        lock_sock(sk);
 286
 287        err = -EINVAL;
 288        if (sk->sk_state != TCP_CLOSE)
 289                goto out_unlock;
 290
 291        /* Check if the address belongs to the host. */
 292        rcu_read_lock();
 293        if (addr_type != IPV6_ADDR_ANY) {
 294                struct net_device *dev = NULL;
 295
 296                if (addr_type & IPV6_ADDR_LINKLOCAL) {
 297                        if (addr_len >= sizeof(struct sockaddr_in6) &&
 298                            addr->l2tp_scope_id) {
 299                                /* Override any existing binding, if another
 300                                 * one is supplied by user.
 301                                 */
 302                                sk->sk_bound_dev_if = addr->l2tp_scope_id;
 303                        }
 304
 305                        /* Binding to link-local address requires an
 306                           interface */
 307                        if (!sk->sk_bound_dev_if)
 308                                goto out_unlock_rcu;
 309
 310                        err = -ENODEV;
 311                        dev = dev_get_by_index_rcu(sock_net(sk),
 312                                                   sk->sk_bound_dev_if);
 313                        if (!dev)
 314                                goto out_unlock_rcu;
 315                }
 316
 317                /* ipv4 addr of the socket is invalid.  Only the
 318                 * unspecified and mapped address have a v4 equivalent.
 319                 */
 320                v4addr = LOOPBACK4_IPV6;
 321                err = -EADDRNOTAVAIL;
 322                if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 323                        goto out_unlock_rcu;
 324        }
 325        rcu_read_unlock();
 326
 327        inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
 328        np->rcv_saddr = addr->l2tp_addr;
 329        np->saddr = addr->l2tp_addr;
 330
 331        l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 332
 333        write_lock_bh(&l2tp_ip6_lock);
 334        sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 335        sk_del_node_init(sk);
 336        write_unlock_bh(&l2tp_ip6_lock);
 337
 338        sock_reset_flag(sk, SOCK_ZAPPED);
 339        release_sock(sk);
 340        return 0;
 341
 342out_unlock_rcu:
 343        rcu_read_unlock();
 344out_unlock:
 345        release_sock(sk);
 346        return err;
 347
 348out_in_use:
 349        read_unlock_bh(&l2tp_ip6_lock);
 350        return err;
 351}
 352
 353static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 354                            int addr_len)
 355{
 356        struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 357        struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 358        struct in6_addr *daddr;
 359        int     addr_type;
 360        int rc;
 361
 362        if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 363                return -EINVAL;
 364
 365        if (addr_len < sizeof(*lsa))
 366                return -EINVAL;
 367
 368        addr_type = ipv6_addr_type(&usin->sin6_addr);
 369        if (addr_type & IPV6_ADDR_MULTICAST)
 370                return -EINVAL;
 371
 372        if (addr_type & IPV6_ADDR_MAPPED) {
 373                daddr = &usin->sin6_addr;
 374                if (ipv4_is_multicast(daddr->s6_addr32[3]))
 375                        return -EINVAL;
 376        }
 377
 378        rc = ip6_datagram_connect(sk, uaddr, addr_len);
 379
 380        lock_sock(sk);
 381
 382        l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 383
 384        write_lock_bh(&l2tp_ip6_lock);
 385        hlist_del_init(&sk->sk_bind_node);
 386        sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 387        write_unlock_bh(&l2tp_ip6_lock);
 388
 389        release_sock(sk);
 390
 391        return rc;
 392}
 393
 394static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 395{
 396        if (sock_flag(sk, SOCK_ZAPPED))
 397                return 0;
 398
 399        return udp_disconnect(sk, flags);
 400}
 401
 402static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 403                            int *uaddr_len, int peer)
 404{
 405        struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 406        struct sock *sk = sock->sk;
 407        struct ipv6_pinfo *np = inet6_sk(sk);
 408        struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 409
 410        lsa->l2tp_family = AF_INET6;
 411        lsa->l2tp_flowinfo = 0;
 412        lsa->l2tp_scope_id = 0;
 413        lsa->l2tp_unused = 0;
 414        if (peer) {
 415                if (!lsk->peer_conn_id)
 416                        return -ENOTCONN;
 417                lsa->l2tp_conn_id = lsk->peer_conn_id;
 418                lsa->l2tp_addr = np->daddr;
 419                if (np->sndflow)
 420                        lsa->l2tp_flowinfo = np->flow_label;
 421        } else {
 422                if (ipv6_addr_any(&np->rcv_saddr))
 423                        lsa->l2tp_addr = np->saddr;
 424                else
 425                        lsa->l2tp_addr = np->rcv_saddr;
 426
 427                lsa->l2tp_conn_id = lsk->conn_id;
 428        }
 429        if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 430                lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 431        *uaddr_len = sizeof(*lsa);
 432        return 0;
 433}
 434
 435static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 436{
 437        int rc;
 438
 439        /* Charge it to the socket, dropping if the queue is full. */
 440        rc = sock_queue_rcv_skb(sk, skb);
 441        if (rc < 0)
 442                goto drop;
 443
 444        return 0;
 445
 446drop:
 447        IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
 448        kfree_skb(skb);
 449        return -1;
 450}
 451
 452static int l2tp_ip6_push_pending_frames(struct sock *sk)
 453{
 454        struct sk_buff *skb;
 455        __be32 *transhdr = NULL;
 456        int err = 0;
 457
 458        skb = skb_peek(&sk->sk_write_queue);
 459        if (skb == NULL)
 460                goto out;
 461
 462        transhdr = (__be32 *)skb_transport_header(skb);
 463        *transhdr = 0;
 464
 465        err = ip6_push_pending_frames(sk);
 466
 467out:
 468        return err;
 469}
 470
 471/* Userspace will call sendmsg() on the tunnel socket to send L2TP
 472 * control frames.
 473 */
 474static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk,
 475                            struct msghdr *msg, size_t len)
 476{
 477        struct ipv6_txoptions opt_space;
 478        struct sockaddr_l2tpip6 *lsa =
 479                (struct sockaddr_l2tpip6 *) msg->msg_name;
 480        struct in6_addr *daddr, *final_p, final;
 481        struct ipv6_pinfo *np = inet6_sk(sk);
 482        struct ipv6_txoptions *opt = NULL;
 483        struct ip6_flowlabel *flowlabel = NULL;
 484        struct dst_entry *dst = NULL;
 485        struct flowi6 fl6;
 486        int addr_len = msg->msg_namelen;
 487        int hlimit = -1;
 488        int tclass = -1;
 489        int dontfrag = -1;
 490        int transhdrlen = 4; /* zero session-id */
 491        int ulen = len + transhdrlen;
 492        int err;
 493
 494        /* Rough check on arithmetic overflow,
 495           better check is made in ip6_append_data().
 496         */
 497        if (len > INT_MAX)
 498                return -EMSGSIZE;
 499
 500        /* Mirror BSD error message compatibility */
 501        if (msg->msg_flags & MSG_OOB)
 502                return -EOPNOTSUPP;
 503
 504        /*
 505         *      Get and verify the address.
 506         */
 507        memset(&fl6, 0, sizeof(fl6));
 508
 509        fl6.flowi6_mark = sk->sk_mark;
 510
 511        if (lsa) {
 512                if (addr_len < SIN6_LEN_RFC2133)
 513                        return -EINVAL;
 514
 515                if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 516                        return -EAFNOSUPPORT;
 517
 518                daddr = &lsa->l2tp_addr;
 519                if (np->sndflow) {
 520                        fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 521                        if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 522                                flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 523                                if (flowlabel == NULL)
 524                                        return -EINVAL;
 525                                daddr = &flowlabel->dst;
 526                        }
 527                }
 528
 529                /*
 530                 * Otherwise it will be difficult to maintain
 531                 * sk->sk_dst_cache.
 532                 */
 533                if (sk->sk_state == TCP_ESTABLISHED &&
 534                    ipv6_addr_equal(daddr, &np->daddr))
 535                        daddr = &np->daddr;
 536
 537                if (addr_len >= sizeof(struct sockaddr_in6) &&
 538                    lsa->l2tp_scope_id &&
 539                    ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 540                        fl6.flowi6_oif = lsa->l2tp_scope_id;
 541        } else {
 542                if (sk->sk_state != TCP_ESTABLISHED)
 543                        return -EDESTADDRREQ;
 544
 545                daddr = &np->daddr;
 546                fl6.flowlabel = np->flow_label;
 547        }
 548
 549        if (fl6.flowi6_oif == 0)
 550                fl6.flowi6_oif = sk->sk_bound_dev_if;
 551
 552        if (msg->msg_controllen) {
 553                opt = &opt_space;
 554                memset(opt, 0, sizeof(struct ipv6_txoptions));
 555                opt->tot_len = sizeof(struct ipv6_txoptions);
 556
 557                err = datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
 558                                        &hlimit, &tclass, &dontfrag);
 559                if (err < 0) {
 560                        fl6_sock_release(flowlabel);
 561                        return err;
 562                }
 563                if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 564                        flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 565                        if (flowlabel == NULL)
 566                                return -EINVAL;
 567                }
 568                if (!(opt->opt_nflen|opt->opt_flen))
 569                        opt = NULL;
 570        }
 571
 572        if (opt == NULL)
 573                opt = np->opt;
 574        if (flowlabel)
 575                opt = fl6_merge_options(&opt_space, flowlabel, opt);
 576        opt = ipv6_fixup_options(&opt_space, opt);
 577
 578        fl6.flowi6_proto = sk->sk_protocol;
 579        if (!ipv6_addr_any(daddr))
 580                fl6.daddr = *daddr;
 581        else
 582                fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 583        if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 584                fl6.saddr = np->saddr;
 585
 586        final_p = fl6_update_dst(&fl6, opt, &final);
 587
 588        if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 589                fl6.flowi6_oif = np->mcast_oif;
 590        else if (!fl6.flowi6_oif)
 591                fl6.flowi6_oif = np->ucast_oif;
 592
 593        security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 594
 595        dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 596        if (IS_ERR(dst)) {
 597                err = PTR_ERR(dst);
 598                goto out;
 599        }
 600
 601        if (hlimit < 0) {
 602                if (ipv6_addr_is_multicast(&fl6.daddr))
 603                        hlimit = np->mcast_hops;
 604                else
 605                        hlimit = np->hop_limit;
 606                if (hlimit < 0)
 607                        hlimit = ip6_dst_hoplimit(dst);
 608        }
 609
 610        if (tclass < 0)
 611                tclass = np->tclass;
 612
 613        if (dontfrag < 0)
 614                dontfrag = np->dontfrag;
 615
 616        if (msg->msg_flags & MSG_CONFIRM)
 617                goto do_confirm;
 618
 619back_from_confirm:
 620        lock_sock(sk);
 621        err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
 622                              ulen, transhdrlen, hlimit, tclass, opt,
 623                              &fl6, (struct rt6_info *)dst,
 624                              msg->msg_flags, dontfrag);
 625        if (err)
 626                ip6_flush_pending_frames(sk);
 627        else if (!(msg->msg_flags & MSG_MORE))
 628                err = l2tp_ip6_push_pending_frames(sk);
 629        release_sock(sk);
 630done:
 631        dst_release(dst);
 632out:
 633        fl6_sock_release(flowlabel);
 634
 635        return err < 0 ? err : len;
 636
 637do_confirm:
 638        dst_confirm(dst);
 639        if (!(msg->msg_flags & MSG_PROBE) || len)
 640                goto back_from_confirm;
 641        err = 0;
 642        goto done;
 643}
 644
 645static int l2tp_ip6_recvmsg(struct kiocb *iocb, struct sock *sk,
 646                            struct msghdr *msg, size_t len, int noblock,
 647                            int flags, int *addr_len)
 648{
 649        struct inet_sock *inet = inet_sk(sk);
 650        struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)msg->msg_name;
 651        size_t copied = 0;
 652        int err = -EOPNOTSUPP;
 653        struct sk_buff *skb;
 654
 655        if (flags & MSG_OOB)
 656                goto out;
 657
 658        if (addr_len)
 659                *addr_len = sizeof(*lsa);
 660
 661        if (flags & MSG_ERRQUEUE)
 662                return ipv6_recv_error(sk, msg, len);
 663
 664        skb = skb_recv_datagram(sk, flags, noblock, &err);
 665        if (!skb)
 666                goto out;
 667
 668        copied = skb->len;
 669        if (len < copied) {
 670                msg->msg_flags |= MSG_TRUNC;
 671                copied = len;
 672        }
 673
 674        err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 675        if (err)
 676                goto done;
 677
 678        sock_recv_timestamp(msg, sk, skb);
 679
 680        /* Copy the address. */
 681        if (lsa) {
 682                lsa->l2tp_family = AF_INET6;
 683                lsa->l2tp_unused = 0;
 684                lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 685                lsa->l2tp_flowinfo = 0;
 686                lsa->l2tp_scope_id = 0;
 687                if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 688                        lsa->l2tp_scope_id = IP6CB(skb)->iif;
 689        }
 690
 691        if (inet->cmsg_flags)
 692                ip_cmsg_recv(msg, skb);
 693
 694        if (flags & MSG_TRUNC)
 695                copied = skb->len;
 696done:
 697        skb_free_datagram(sk, skb);
 698out:
 699        return err ? err : copied;
 700}
 701
 702static struct proto l2tp_ip6_prot = {
 703        .name              = "L2TP/IPv6",
 704        .owner             = THIS_MODULE,
 705        .init              = l2tp_ip6_open,
 706        .close             = l2tp_ip6_close,
 707        .bind              = l2tp_ip6_bind,
 708        .connect           = l2tp_ip6_connect,
 709        .disconnect        = l2tp_ip6_disconnect,
 710        .ioctl             = udp_ioctl,
 711        .destroy           = l2tp_ip6_destroy_sock,
 712        .setsockopt        = ipv6_setsockopt,
 713        .getsockopt        = ipv6_getsockopt,
 714        .sendmsg           = l2tp_ip6_sendmsg,
 715        .recvmsg           = l2tp_ip6_recvmsg,
 716        .backlog_rcv       = l2tp_ip6_backlog_recv,
 717        .hash              = inet_hash,
 718        .unhash            = inet_unhash,
 719        .obj_size          = sizeof(struct l2tp_ip6_sock),
 720#ifdef CONFIG_COMPAT
 721        .compat_setsockopt = compat_ipv6_setsockopt,
 722        .compat_getsockopt = compat_ipv6_getsockopt,
 723#endif
 724};
 725
 726static const struct proto_ops l2tp_ip6_ops = {
 727        .family            = PF_INET6,
 728        .owner             = THIS_MODULE,
 729        .release           = inet6_release,
 730        .bind              = inet6_bind,
 731        .connect           = inet_dgram_connect,
 732        .socketpair        = sock_no_socketpair,
 733        .accept            = sock_no_accept,
 734        .getname           = l2tp_ip6_getname,
 735        .poll              = datagram_poll,
 736        .ioctl             = inet6_ioctl,
 737        .listen            = sock_no_listen,
 738        .shutdown          = inet_shutdown,
 739        .setsockopt        = sock_common_setsockopt,
 740        .getsockopt        = sock_common_getsockopt,
 741        .sendmsg           = inet_sendmsg,
 742        .recvmsg           = sock_common_recvmsg,
 743        .mmap              = sock_no_mmap,
 744        .sendpage          = sock_no_sendpage,
 745#ifdef CONFIG_COMPAT
 746        .compat_setsockopt = compat_sock_common_setsockopt,
 747        .compat_getsockopt = compat_sock_common_getsockopt,
 748#endif
 749};
 750
 751static struct inet_protosw l2tp_ip6_protosw = {
 752        .type           = SOCK_DGRAM,
 753        .protocol       = IPPROTO_L2TP,
 754        .prot           = &l2tp_ip6_prot,
 755        .ops            = &l2tp_ip6_ops,
 756        .no_check       = 0,
 757};
 758
 759static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 760        .handler        = l2tp_ip6_recv,
 761};
 762
 763static int __init l2tp_ip6_init(void)
 764{
 765        int err;
 766
 767        pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 768
 769        err = proto_register(&l2tp_ip6_prot, 1);
 770        if (err != 0)
 771                goto out;
 772
 773        err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 774        if (err)
 775                goto out1;
 776
 777        inet6_register_protosw(&l2tp_ip6_protosw);
 778        return 0;
 779
 780out1:
 781        proto_unregister(&l2tp_ip6_prot);
 782out:
 783        return err;
 784}
 785
 786static void __exit l2tp_ip6_exit(void)
 787{
 788        inet6_unregister_protosw(&l2tp_ip6_protosw);
 789        inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 790        proto_unregister(&l2tp_ip6_prot);
 791}
 792
 793module_init(l2tp_ip6_init);
 794module_exit(l2tp_ip6_exit);
 795
 796MODULE_LICENSE("GPL");
 797MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 798MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 799MODULE_VERSION("1.0");
 800
 801/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 802 * enums
 803 */
 804MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 805
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