Root/net/l2tp/l2tp_ip6.c

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 sock *sk;
64
65    sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
66        const struct in6_addr *addr = inet6_rcv_saddr(sk);
67        struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
68
69        if (l2tp == NULL)
70            continue;
71
72        if ((l2tp->conn_id == tunnel_id) &&
73            net_eq(sock_net(sk), net) &&
74            !(addr && ipv6_addr_equal(addr, laddr)) &&
75            !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
76            goto found;
77    }
78
79    sk = NULL;
80found:
81    return sk;
82}
83
84static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
85                        struct in6_addr *laddr,
86                        int dif, u32 tunnel_id)
87{
88    struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
89    if (sk)
90        sock_hold(sk);
91
92    return sk;
93}
94
95/* When processing receive frames, there are two cases to
96 * consider. Data frames consist of a non-zero session-id and an
97 * optional cookie. Control frames consist of a regular L2TP header
98 * preceded by 32-bits of zeros.
99 *
100 * L2TPv3 Session Header Over IP
101 *
102 * 0 1 2 3
103 * 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
104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
105 * | Session ID |
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 * | Cookie (optional, maximum 64 bits)...
108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109 * |
110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
111 *
112 * L2TPv3 Control Message Header Over IP
113 *
114 * 0 1 2 3
115 * 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
116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
117 * | (32 bits of zeros) |
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121 * | Control Connection ID |
122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123 * | Ns | Nr |
124 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
125 *
126 * All control frames are passed to userspace.
127 */
128static int l2tp_ip6_recv(struct sk_buff *skb)
129{
130    struct sock *sk;
131    u32 session_id;
132    u32 tunnel_id;
133    unsigned char *ptr, *optr;
134    struct l2tp_session *session;
135    struct l2tp_tunnel *tunnel = NULL;
136    int length;
137
138    /* Point to L2TP header */
139    optr = ptr = skb->data;
140
141    if (!pskb_may_pull(skb, 4))
142        goto discard;
143
144    session_id = ntohl(*((__be32 *) ptr));
145    ptr += 4;
146
147    /* RFC3931: L2TP/IP packets have the first 4 bytes containing
148     * the session_id. If it is 0, the packet is a L2TP control
149     * frame and the session_id value can be discarded.
150     */
151    if (session_id == 0) {
152        __skb_pull(skb, 4);
153        goto pass_up;
154    }
155
156    /* Ok, this is a data packet. Lookup the session. */
157    session = l2tp_session_find(&init_net, NULL, session_id);
158    if (session == NULL)
159        goto discard;
160
161    tunnel = session->tunnel;
162    if (tunnel == NULL)
163        goto discard;
164
165    /* Trace packet contents, if enabled */
166    if (tunnel->debug & L2TP_MSG_DATA) {
167        length = min(32u, skb->len);
168        if (!pskb_may_pull(skb, length))
169            goto discard;
170
171        pr_debug("%s: ip recv\n", tunnel->name);
172        print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
173    }
174
175    l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
176             tunnel->recv_payload_hook);
177    return 0;
178
179pass_up:
180    /* Get the tunnel_id from the L2TP header */
181    if (!pskb_may_pull(skb, 12))
182        goto discard;
183
184    if ((skb->data[0] & 0xc0) != 0xc0)
185        goto discard;
186
187    tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
188    tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
189    if (tunnel != NULL)
190        sk = tunnel->sock;
191    else {
192        struct ipv6hdr *iph = ipv6_hdr(skb);
193
194        read_lock_bh(&l2tp_ip6_lock);
195        sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
196                        0, tunnel_id);
197        read_unlock_bh(&l2tp_ip6_lock);
198    }
199
200    if (sk == NULL)
201        goto discard;
202
203    sock_hold(sk);
204
205    if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
206        goto discard_put;
207
208    nf_reset(skb);
209
210    return sk_receive_skb(sk, skb, 1);
211
212discard_put:
213    sock_put(sk);
214
215discard:
216    kfree_skb(skb);
217    return 0;
218}
219
220static int l2tp_ip6_open(struct sock *sk)
221{
222    /* Prevent autobind. We don't have ports. */
223    inet_sk(sk)->inet_num = IPPROTO_L2TP;
224
225    write_lock_bh(&l2tp_ip6_lock);
226    sk_add_node(sk, &l2tp_ip6_table);
227    write_unlock_bh(&l2tp_ip6_lock);
228
229    return 0;
230}
231
232static void l2tp_ip6_close(struct sock *sk, long timeout)
233{
234    write_lock_bh(&l2tp_ip6_lock);
235    hlist_del_init(&sk->sk_bind_node);
236    sk_del_node_init(sk);
237    write_unlock_bh(&l2tp_ip6_lock);
238
239    sk_common_release(sk);
240}
241
242static void l2tp_ip6_destroy_sock(struct sock *sk)
243{
244    struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
245
246    lock_sock(sk);
247    ip6_flush_pending_frames(sk);
248    release_sock(sk);
249
250    if (tunnel) {
251        l2tp_tunnel_closeall(tunnel);
252        sock_put(sk);
253    }
254
255    inet6_destroy_sock(sk);
256}
257
258static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
259{
260    struct inet_sock *inet = inet_sk(sk);
261    struct ipv6_pinfo *np = inet6_sk(sk);
262    struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
263    __be32 v4addr = 0;
264    int addr_type;
265    int err;
266
267    if (!sock_flag(sk, SOCK_ZAPPED))
268        return -EINVAL;
269    if (addr->l2tp_family != AF_INET6)
270        return -EINVAL;
271    if (addr_len < sizeof(*addr))
272        return -EINVAL;
273
274    addr_type = ipv6_addr_type(&addr->l2tp_addr);
275
276    /* l2tp_ip6 sockets are IPv6 only */
277    if (addr_type == IPV6_ADDR_MAPPED)
278        return -EADDRNOTAVAIL;
279
280    /* L2TP is point-point, not multicast */
281    if (addr_type & IPV6_ADDR_MULTICAST)
282        return -EADDRNOTAVAIL;
283
284    err = -EADDRINUSE;
285    read_lock_bh(&l2tp_ip6_lock);
286    if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
287                   sk->sk_bound_dev_if, addr->l2tp_conn_id))
288        goto out_in_use;
289    read_unlock_bh(&l2tp_ip6_lock);
290
291    lock_sock(sk);
292
293    err = -EINVAL;
294    if (sk->sk_state != TCP_CLOSE)
295        goto out_unlock;
296
297    /* Check if the address belongs to the host. */
298    rcu_read_lock();
299    if (addr_type != IPV6_ADDR_ANY) {
300        struct net_device *dev = NULL;
301
302        if (addr_type & IPV6_ADDR_LINKLOCAL) {
303            if (addr_len >= sizeof(struct sockaddr_in6) &&
304                addr->l2tp_scope_id) {
305                /* Override any existing binding, if another
306                 * one is supplied by user.
307                 */
308                sk->sk_bound_dev_if = addr->l2tp_scope_id;
309            }
310
311            /* Binding to link-local address requires an
312               interface */
313            if (!sk->sk_bound_dev_if)
314                goto out_unlock_rcu;
315
316            err = -ENODEV;
317            dev = dev_get_by_index_rcu(sock_net(sk),
318                           sk->sk_bound_dev_if);
319            if (!dev)
320                goto out_unlock_rcu;
321        }
322
323        /* ipv4 addr of the socket is invalid. Only the
324         * unspecified and mapped address have a v4 equivalent.
325         */
326        v4addr = LOOPBACK4_IPV6;
327        err = -EADDRNOTAVAIL;
328        if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
329            goto out_unlock_rcu;
330    }
331    rcu_read_unlock();
332
333    inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
334    sk->sk_v6_rcv_saddr = addr->l2tp_addr;
335    np->saddr = addr->l2tp_addr;
336
337    l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
338
339    write_lock_bh(&l2tp_ip6_lock);
340    sk_add_bind_node(sk, &l2tp_ip6_bind_table);
341    sk_del_node_init(sk);
342    write_unlock_bh(&l2tp_ip6_lock);
343
344    sock_reset_flag(sk, SOCK_ZAPPED);
345    release_sock(sk);
346    return 0;
347
348out_unlock_rcu:
349    rcu_read_unlock();
350out_unlock:
351    release_sock(sk);
352    return err;
353
354out_in_use:
355    read_unlock_bh(&l2tp_ip6_lock);
356    return err;
357}
358
359static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
360                int addr_len)
361{
362    struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
363    struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
364    struct in6_addr *daddr;
365    int addr_type;
366    int rc;
367
368    if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
369        return -EINVAL;
370
371    if (addr_len < sizeof(*lsa))
372        return -EINVAL;
373
374    if (usin->sin6_family != AF_INET6)
375        return -EINVAL;
376
377    addr_type = ipv6_addr_type(&usin->sin6_addr);
378    if (addr_type & IPV6_ADDR_MULTICAST)
379        return -EINVAL;
380
381    if (addr_type & IPV6_ADDR_MAPPED) {
382        daddr = &usin->sin6_addr;
383        if (ipv4_is_multicast(daddr->s6_addr32[3]))
384            return -EINVAL;
385    }
386
387    rc = ip6_datagram_connect(sk, uaddr, addr_len);
388
389    lock_sock(sk);
390
391    l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
392
393    write_lock_bh(&l2tp_ip6_lock);
394    hlist_del_init(&sk->sk_bind_node);
395    sk_add_bind_node(sk, &l2tp_ip6_bind_table);
396    write_unlock_bh(&l2tp_ip6_lock);
397
398    release_sock(sk);
399
400    return rc;
401}
402
403static int l2tp_ip6_disconnect(struct sock *sk, int flags)
404{
405    if (sock_flag(sk, SOCK_ZAPPED))
406        return 0;
407
408    return udp_disconnect(sk, flags);
409}
410
411static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
412                int *uaddr_len, int peer)
413{
414    struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
415    struct sock *sk = sock->sk;
416    struct ipv6_pinfo *np = inet6_sk(sk);
417    struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
418
419    lsa->l2tp_family = AF_INET6;
420    lsa->l2tp_flowinfo = 0;
421    lsa->l2tp_scope_id = 0;
422    lsa->l2tp_unused = 0;
423    if (peer) {
424        if (!lsk->peer_conn_id)
425            return -ENOTCONN;
426        lsa->l2tp_conn_id = lsk->peer_conn_id;
427        lsa->l2tp_addr = sk->sk_v6_daddr;
428        if (np->sndflow)
429            lsa->l2tp_flowinfo = np->flow_label;
430    } else {
431        if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
432            lsa->l2tp_addr = np->saddr;
433        else
434            lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
435
436        lsa->l2tp_conn_id = lsk->conn_id;
437    }
438    if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
439        lsa->l2tp_scope_id = sk->sk_bound_dev_if;
440    *uaddr_len = sizeof(*lsa);
441    return 0;
442}
443
444static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
445{
446    int rc;
447
448    /* Charge it to the socket, dropping if the queue is full. */
449    rc = sock_queue_rcv_skb(sk, skb);
450    if (rc < 0)
451        goto drop;
452
453    return 0;
454
455drop:
456    IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
457    kfree_skb(skb);
458    return -1;
459}
460
461static int l2tp_ip6_push_pending_frames(struct sock *sk)
462{
463    struct sk_buff *skb;
464    __be32 *transhdr = NULL;
465    int err = 0;
466
467    skb = skb_peek(&sk->sk_write_queue);
468    if (skb == NULL)
469        goto out;
470
471    transhdr = (__be32 *)skb_transport_header(skb);
472    *transhdr = 0;
473
474    err = ip6_push_pending_frames(sk);
475
476out:
477    return err;
478}
479
480/* Userspace will call sendmsg() on the tunnel socket to send L2TP
481 * control frames.
482 */
483static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk,
484                struct msghdr *msg, size_t len)
485{
486    struct ipv6_txoptions opt_space;
487    DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
488    struct in6_addr *daddr, *final_p, final;
489    struct ipv6_pinfo *np = inet6_sk(sk);
490    struct ipv6_txoptions *opt = NULL;
491    struct ip6_flowlabel *flowlabel = NULL;
492    struct dst_entry *dst = NULL;
493    struct flowi6 fl6;
494    int addr_len = msg->msg_namelen;
495    int hlimit = -1;
496    int tclass = -1;
497    int dontfrag = -1;
498    int transhdrlen = 4; /* zero session-id */
499    int ulen = len + transhdrlen;
500    int err;
501
502    /* Rough check on arithmetic overflow,
503       better check is made in ip6_append_data().
504     */
505    if (len > INT_MAX)
506        return -EMSGSIZE;
507
508    /* Mirror BSD error message compatibility */
509    if (msg->msg_flags & MSG_OOB)
510        return -EOPNOTSUPP;
511
512    /*
513     * Get and verify the address.
514     */
515    memset(&fl6, 0, sizeof(fl6));
516
517    fl6.flowi6_mark = sk->sk_mark;
518
519    if (lsa) {
520        if (addr_len < SIN6_LEN_RFC2133)
521            return -EINVAL;
522
523        if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
524            return -EAFNOSUPPORT;
525
526        daddr = &lsa->l2tp_addr;
527        if (np->sndflow) {
528            fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
529            if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
530                flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
531                if (flowlabel == NULL)
532                    return -EINVAL;
533            }
534        }
535
536        /*
537         * Otherwise it will be difficult to maintain
538         * sk->sk_dst_cache.
539         */
540        if (sk->sk_state == TCP_ESTABLISHED &&
541            ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
542            daddr = &sk->sk_v6_daddr;
543
544        if (addr_len >= sizeof(struct sockaddr_in6) &&
545            lsa->l2tp_scope_id &&
546            ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
547            fl6.flowi6_oif = lsa->l2tp_scope_id;
548    } else {
549        if (sk->sk_state != TCP_ESTABLISHED)
550            return -EDESTADDRREQ;
551
552        daddr = &sk->sk_v6_daddr;
553        fl6.flowlabel = np->flow_label;
554    }
555
556    if (fl6.flowi6_oif == 0)
557        fl6.flowi6_oif = sk->sk_bound_dev_if;
558
559    if (msg->msg_controllen) {
560        opt = &opt_space;
561        memset(opt, 0, sizeof(struct ipv6_txoptions));
562        opt->tot_len = sizeof(struct ipv6_txoptions);
563
564        err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
565                        &hlimit, &tclass, &dontfrag);
566        if (err < 0) {
567            fl6_sock_release(flowlabel);
568            return err;
569        }
570        if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
571            flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
572            if (flowlabel == NULL)
573                return -EINVAL;
574        }
575        if (!(opt->opt_nflen|opt->opt_flen))
576            opt = NULL;
577    }
578
579    if (opt == NULL)
580        opt = np->opt;
581    if (flowlabel)
582        opt = fl6_merge_options(&opt_space, flowlabel, opt);
583    opt = ipv6_fixup_options(&opt_space, opt);
584
585    fl6.flowi6_proto = sk->sk_protocol;
586    if (!ipv6_addr_any(daddr))
587        fl6.daddr = *daddr;
588    else
589        fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
590    if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
591        fl6.saddr = np->saddr;
592
593    final_p = fl6_update_dst(&fl6, opt, &final);
594
595    if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
596        fl6.flowi6_oif = np->mcast_oif;
597    else if (!fl6.flowi6_oif)
598        fl6.flowi6_oif = np->ucast_oif;
599
600    security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
601
602    dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
603    if (IS_ERR(dst)) {
604        err = PTR_ERR(dst);
605        goto out;
606    }
607
608    if (hlimit < 0) {
609        if (ipv6_addr_is_multicast(&fl6.daddr))
610            hlimit = np->mcast_hops;
611        else
612            hlimit = np->hop_limit;
613        if (hlimit < 0)
614            hlimit = ip6_dst_hoplimit(dst);
615    }
616
617    if (tclass < 0)
618        tclass = np->tclass;
619
620    if (dontfrag < 0)
621        dontfrag = np->dontfrag;
622
623    if (msg->msg_flags & MSG_CONFIRM)
624        goto do_confirm;
625
626back_from_confirm:
627    lock_sock(sk);
628    err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
629                  ulen, transhdrlen, hlimit, tclass, opt,
630                  &fl6, (struct rt6_info *)dst,
631                  msg->msg_flags, dontfrag);
632    if (err)
633        ip6_flush_pending_frames(sk);
634    else if (!(msg->msg_flags & MSG_MORE))
635        err = l2tp_ip6_push_pending_frames(sk);
636    release_sock(sk);
637done:
638    dst_release(dst);
639out:
640    fl6_sock_release(flowlabel);
641
642    return err < 0 ? err : len;
643
644do_confirm:
645    dst_confirm(dst);
646    if (!(msg->msg_flags & MSG_PROBE) || len)
647        goto back_from_confirm;
648    err = 0;
649    goto done;
650}
651
652static int l2tp_ip6_recvmsg(struct kiocb *iocb, struct sock *sk,
653                struct msghdr *msg, size_t len, int noblock,
654                int flags, int *addr_len)
655{
656    struct ipv6_pinfo *np = inet6_sk(sk);
657    DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
658    size_t copied = 0;
659    int err = -EOPNOTSUPP;
660    struct sk_buff *skb;
661
662    if (flags & MSG_OOB)
663        goto out;
664
665    if (addr_len)
666        *addr_len = sizeof(*lsa);
667
668    if (flags & MSG_ERRQUEUE)
669        return ipv6_recv_error(sk, msg, len, addr_len);
670
671    skb = skb_recv_datagram(sk, flags, noblock, &err);
672    if (!skb)
673        goto out;
674
675    copied = skb->len;
676    if (len < copied) {
677        msg->msg_flags |= MSG_TRUNC;
678        copied = len;
679    }
680
681    err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
682    if (err)
683        goto done;
684
685    sock_recv_timestamp(msg, sk, skb);
686
687    /* Copy the address. */
688    if (lsa) {
689        lsa->l2tp_family = AF_INET6;
690        lsa->l2tp_unused = 0;
691        lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
692        lsa->l2tp_flowinfo = 0;
693        lsa->l2tp_scope_id = 0;
694        lsa->l2tp_conn_id = 0;
695        if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
696            lsa->l2tp_scope_id = IP6CB(skb)->iif;
697    }
698
699    if (np->rxopt.all)
700        ip6_datagram_recv_ctl(sk, msg, skb);
701
702    if (flags & MSG_TRUNC)
703        copied = skb->len;
704done:
705    skb_free_datagram(sk, skb);
706out:
707    return err ? err : copied;
708}
709
710static struct proto l2tp_ip6_prot = {
711    .name = "L2TP/IPv6",
712    .owner = THIS_MODULE,
713    .init = l2tp_ip6_open,
714    .close = l2tp_ip6_close,
715    .bind = l2tp_ip6_bind,
716    .connect = l2tp_ip6_connect,
717    .disconnect = l2tp_ip6_disconnect,
718    .ioctl = udp_ioctl,
719    .destroy = l2tp_ip6_destroy_sock,
720    .setsockopt = ipv6_setsockopt,
721    .getsockopt = ipv6_getsockopt,
722    .sendmsg = l2tp_ip6_sendmsg,
723    .recvmsg = l2tp_ip6_recvmsg,
724    .backlog_rcv = l2tp_ip6_backlog_recv,
725    .hash = inet_hash,
726    .unhash = inet_unhash,
727    .obj_size = sizeof(struct l2tp_ip6_sock),
728#ifdef CONFIG_COMPAT
729    .compat_setsockopt = compat_ipv6_setsockopt,
730    .compat_getsockopt = compat_ipv6_getsockopt,
731#endif
732};
733
734static const struct proto_ops l2tp_ip6_ops = {
735    .family = PF_INET6,
736    .owner = THIS_MODULE,
737    .release = inet6_release,
738    .bind = inet6_bind,
739    .connect = inet_dgram_connect,
740    .socketpair = sock_no_socketpair,
741    .accept = sock_no_accept,
742    .getname = l2tp_ip6_getname,
743    .poll = datagram_poll,
744    .ioctl = inet6_ioctl,
745    .listen = sock_no_listen,
746    .shutdown = inet_shutdown,
747    .setsockopt = sock_common_setsockopt,
748    .getsockopt = sock_common_getsockopt,
749    .sendmsg = inet_sendmsg,
750    .recvmsg = sock_common_recvmsg,
751    .mmap = sock_no_mmap,
752    .sendpage = sock_no_sendpage,
753#ifdef CONFIG_COMPAT
754    .compat_setsockopt = compat_sock_common_setsockopt,
755    .compat_getsockopt = compat_sock_common_getsockopt,
756#endif
757};
758
759static struct inet_protosw l2tp_ip6_protosw = {
760    .type = SOCK_DGRAM,
761    .protocol = IPPROTO_L2TP,
762    .prot = &l2tp_ip6_prot,
763    .ops = &l2tp_ip6_ops,
764    .no_check = 0,
765};
766
767static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
768    .handler = l2tp_ip6_recv,
769};
770
771static int __init l2tp_ip6_init(void)
772{
773    int err;
774
775    pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
776
777    err = proto_register(&l2tp_ip6_prot, 1);
778    if (err != 0)
779        goto out;
780
781    err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
782    if (err)
783        goto out1;
784
785    inet6_register_protosw(&l2tp_ip6_protosw);
786    return 0;
787
788out1:
789    proto_unregister(&l2tp_ip6_prot);
790out:
791    return err;
792}
793
794static void __exit l2tp_ip6_exit(void)
795{
796    inet6_unregister_protosw(&l2tp_ip6_protosw);
797    inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
798    proto_unregister(&l2tp_ip6_prot);
799}
800
801module_init(l2tp_ip6_init);
802module_exit(l2tp_ip6_exit);
803
804MODULE_LICENSE("GPL");
805MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
806MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
807MODULE_VERSION("1.0");
808
809/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
810 * enums
811 */
812MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
813

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