Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
[sfrench/cifs-2.6.git] / net / dccp / ipv6.c
1 /*
2  *      DCCP over IPv6
3  *      Linux INET6 implementation
4  *
5  *      Based on net/dccp6/ipv6.c
6  *
7  *      Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
8  *
9  *      This program is free software; you can redistribute it and/or
10  *      modify it under the terms of the GNU General Public License
11  *      as published by the Free Software Foundation; either version
12  *      2 of the License, or (at your option) any later version.
13  */
14
15 #include <linux/module.h>
16 #include <linux/random.h>
17 #include <linux/slab.h>
18 #include <linux/xfrm.h>
19
20 #include <net/addrconf.h>
21 #include <net/inet_common.h>
22 #include <net/inet_hashtables.h>
23 #include <net/inet_sock.h>
24 #include <net/inet6_connection_sock.h>
25 #include <net/inet6_hashtables.h>
26 #include <net/ip6_route.h>
27 #include <net/ipv6.h>
28 #include <net/protocol.h>
29 #include <net/transp_v6.h>
30 #include <net/ip6_checksum.h>
31 #include <net/xfrm.h>
32 #include <net/secure_seq.h>
33
34 #include "dccp.h"
35 #include "ipv6.h"
36 #include "feat.h"
37
38 /* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */
39
40 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
41 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
42
43 static void dccp_v6_hash(struct sock *sk)
44 {
45         if (sk->sk_state != DCCP_CLOSED) {
46                 if (inet_csk(sk)->icsk_af_ops == &dccp_ipv6_mapped) {
47                         inet_hash(sk);
48                         return;
49                 }
50                 local_bh_disable();
51                 __inet6_hash(sk, NULL);
52                 local_bh_enable();
53         }
54 }
55
56 /* add pseudo-header to DCCP checksum stored in skb->csum */
57 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
58                                       const struct in6_addr *saddr,
59                                       const struct in6_addr *daddr)
60 {
61         return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
62 }
63
64 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
65 {
66         struct ipv6_pinfo *np = inet6_sk(sk);
67         struct dccp_hdr *dh = dccp_hdr(skb);
68
69         dccp_csum_outgoing(skb);
70         dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
71 }
72
73 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
74 {
75         return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
76                                              ipv6_hdr(skb)->saddr.s6_addr32,
77                                              dccp_hdr(skb)->dccph_dport,
78                                              dccp_hdr(skb)->dccph_sport     );
79
80 }
81
82 static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
83                         u8 type, u8 code, int offset, __be32 info)
84 {
85         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
86         const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
87         struct dccp_sock *dp;
88         struct ipv6_pinfo *np;
89         struct sock *sk;
90         int err;
91         __u64 seq;
92         struct net *net = dev_net(skb->dev);
93
94         if (skb->len < offset + sizeof(*dh) ||
95             skb->len < offset + __dccp_basic_hdr_len(dh)) {
96                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
97                                    ICMP6_MIB_INERRORS);
98                 return;
99         }
100
101         sk = inet6_lookup(net, &dccp_hashinfo,
102                         &hdr->daddr, dh->dccph_dport,
103                         &hdr->saddr, dh->dccph_sport, inet6_iif(skb));
104
105         if (sk == NULL) {
106                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
107                                    ICMP6_MIB_INERRORS);
108                 return;
109         }
110
111         if (sk->sk_state == DCCP_TIME_WAIT) {
112                 inet_twsk_put(inet_twsk(sk));
113                 return;
114         }
115
116         bh_lock_sock(sk);
117         if (sock_owned_by_user(sk))
118                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
119
120         if (sk->sk_state == DCCP_CLOSED)
121                 goto out;
122
123         dp = dccp_sk(sk);
124         seq = dccp_hdr_seq(dh);
125         if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
126             !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
127                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
128                 goto out;
129         }
130
131         np = inet6_sk(sk);
132
133         if (type == NDISC_REDIRECT) {
134                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
135
136                 if (dst)
137                         dst->ops->redirect(dst, sk, skb);
138                 goto out;
139         }
140
141         if (type == ICMPV6_PKT_TOOBIG) {
142                 struct dst_entry *dst = NULL;
143
144                 if (!ip6_sk_accept_pmtu(sk))
145                         goto out;
146
147                 if (sock_owned_by_user(sk))
148                         goto out;
149                 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
150                         goto out;
151
152                 dst = inet6_csk_update_pmtu(sk, ntohl(info));
153                 if (!dst)
154                         goto out;
155
156                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
157                         dccp_sync_mss(sk, dst_mtu(dst));
158                 goto out;
159         }
160
161         icmpv6_err_convert(type, code, &err);
162
163         /* Might be for an request_sock */
164         switch (sk->sk_state) {
165                 struct request_sock *req, **prev;
166         case DCCP_LISTEN:
167                 if (sock_owned_by_user(sk))
168                         goto out;
169
170                 req = inet6_csk_search_req(sk, &prev, dh->dccph_dport,
171                                            &hdr->daddr, &hdr->saddr,
172                                            inet6_iif(skb));
173                 if (req == NULL)
174                         goto out;
175
176                 /*
177                  * ICMPs are not backlogged, hence we cannot get an established
178                  * socket here.
179                  */
180                 WARN_ON(req->sk != NULL);
181
182                 if (!between48(seq, dccp_rsk(req)->dreq_iss,
183                                     dccp_rsk(req)->dreq_gss)) {
184                         NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
185                         goto out;
186                 }
187
188                 inet_csk_reqsk_queue_drop(sk, req, prev);
189                 goto out;
190
191         case DCCP_REQUESTING:
192         case DCCP_RESPOND:  /* Cannot happen.
193                                It can, it SYNs are crossed. --ANK */
194                 if (!sock_owned_by_user(sk)) {
195                         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
196                         sk->sk_err = err;
197                         /*
198                          * Wake people up to see the error
199                          * (see connect in sock.c)
200                          */
201                         sk->sk_error_report(sk);
202                         dccp_done(sk);
203                 } else
204                         sk->sk_err_soft = err;
205                 goto out;
206         }
207
208         if (!sock_owned_by_user(sk) && np->recverr) {
209                 sk->sk_err = err;
210                 sk->sk_error_report(sk);
211         } else
212                 sk->sk_err_soft = err;
213
214 out:
215         bh_unlock_sock(sk);
216         sock_put(sk);
217 }
218
219
220 static int dccp_v6_send_response(struct sock *sk, struct request_sock *req)
221 {
222         struct inet_request_sock *ireq = inet_rsk(req);
223         struct ipv6_pinfo *np = inet6_sk(sk);
224         struct sk_buff *skb;
225         struct in6_addr *final_p, final;
226         struct flowi6 fl6;
227         int err = -1;
228         struct dst_entry *dst;
229
230         memset(&fl6, 0, sizeof(fl6));
231         fl6.flowi6_proto = IPPROTO_DCCP;
232         fl6.daddr = ireq->ir_v6_rmt_addr;
233         fl6.saddr = ireq->ir_v6_loc_addr;
234         fl6.flowlabel = 0;
235         fl6.flowi6_oif = ireq->ir_iif;
236         fl6.fl6_dport = ireq->ir_rmt_port;
237         fl6.fl6_sport = htons(ireq->ir_num);
238         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
239
240
241         final_p = fl6_update_dst(&fl6, np->opt, &final);
242
243         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
244         if (IS_ERR(dst)) {
245                 err = PTR_ERR(dst);
246                 dst = NULL;
247                 goto done;
248         }
249
250         skb = dccp_make_response(sk, dst, req);
251         if (skb != NULL) {
252                 struct dccp_hdr *dh = dccp_hdr(skb);
253
254                 dh->dccph_checksum = dccp_v6_csum_finish(skb,
255                                                          &ireq->ir_v6_loc_addr,
256                                                          &ireq->ir_v6_rmt_addr);
257                 fl6.daddr = ireq->ir_v6_rmt_addr;
258                 err = ip6_xmit(sk, skb, &fl6, np->opt, np->tclass);
259                 err = net_xmit_eval(err);
260         }
261
262 done:
263         dst_release(dst);
264         return err;
265 }
266
267 static void dccp_v6_reqsk_destructor(struct request_sock *req)
268 {
269         dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
270         kfree_skb(inet_rsk(req)->pktopts);
271 }
272
273 static void dccp_v6_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
274 {
275         const struct ipv6hdr *rxip6h;
276         struct sk_buff *skb;
277         struct flowi6 fl6;
278         struct net *net = dev_net(skb_dst(rxskb)->dev);
279         struct sock *ctl_sk = net->dccp.v6_ctl_sk;
280         struct dst_entry *dst;
281
282         if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
283                 return;
284
285         if (!ipv6_unicast_destination(rxskb))
286                 return;
287
288         skb = dccp_ctl_make_reset(ctl_sk, rxskb);
289         if (skb == NULL)
290                 return;
291
292         rxip6h = ipv6_hdr(rxskb);
293         dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
294                                                             &rxip6h->daddr);
295
296         memset(&fl6, 0, sizeof(fl6));
297         fl6.daddr = rxip6h->saddr;
298         fl6.saddr = rxip6h->daddr;
299
300         fl6.flowi6_proto = IPPROTO_DCCP;
301         fl6.flowi6_oif = inet6_iif(rxskb);
302         fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
303         fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
304         security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
305
306         /* sk = NULL, but it is safe for now. RST socket required. */
307         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
308         if (!IS_ERR(dst)) {
309                 skb_dst_set(skb, dst);
310                 ip6_xmit(ctl_sk, skb, &fl6, NULL, 0);
311                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
312                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
313                 return;
314         }
315
316         kfree_skb(skb);
317 }
318
319 static struct request_sock_ops dccp6_request_sock_ops = {
320         .family         = AF_INET6,
321         .obj_size       = sizeof(struct dccp6_request_sock),
322         .rtx_syn_ack    = dccp_v6_send_response,
323         .send_ack       = dccp_reqsk_send_ack,
324         .destructor     = dccp_v6_reqsk_destructor,
325         .send_reset     = dccp_v6_ctl_send_reset,
326         .syn_ack_timeout = dccp_syn_ack_timeout,
327 };
328
329 static struct sock *dccp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
330 {
331         const struct dccp_hdr *dh = dccp_hdr(skb);
332         const struct ipv6hdr *iph = ipv6_hdr(skb);
333         struct sock *nsk;
334         struct request_sock **prev;
335         /* Find possible connection requests. */
336         struct request_sock *req = inet6_csk_search_req(sk, &prev,
337                                                         dh->dccph_sport,
338                                                         &iph->saddr,
339                                                         &iph->daddr,
340                                                         inet6_iif(skb));
341         if (req != NULL)
342                 return dccp_check_req(sk, skb, req, prev);
343
344         nsk = __inet6_lookup_established(sock_net(sk), &dccp_hashinfo,
345                                          &iph->saddr, dh->dccph_sport,
346                                          &iph->daddr, ntohs(dh->dccph_dport),
347                                          inet6_iif(skb));
348         if (nsk != NULL) {
349                 if (nsk->sk_state != DCCP_TIME_WAIT) {
350                         bh_lock_sock(nsk);
351                         return nsk;
352                 }
353                 inet_twsk_put(inet_twsk(nsk));
354                 return NULL;
355         }
356
357         return sk;
358 }
359
360 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
361 {
362         struct request_sock *req;
363         struct dccp_request_sock *dreq;
364         struct inet_request_sock *ireq;
365         struct ipv6_pinfo *np = inet6_sk(sk);
366         const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
367         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
368
369         if (skb->protocol == htons(ETH_P_IP))
370                 return dccp_v4_conn_request(sk, skb);
371
372         if (!ipv6_unicast_destination(skb))
373                 return 0;       /* discard, don't send a reset here */
374
375         if (dccp_bad_service_code(sk, service)) {
376                 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
377                 goto drop;
378         }
379         /*
380          * There are no SYN attacks on IPv6, yet...
381          */
382         dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
383         if (inet_csk_reqsk_queue_is_full(sk))
384                 goto drop;
385
386         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
387                 goto drop;
388
389         req = inet6_reqsk_alloc(&dccp6_request_sock_ops);
390         if (req == NULL)
391                 goto drop;
392
393         if (dccp_reqsk_init(req, dccp_sk(sk), skb))
394                 goto drop_and_free;
395
396         dreq = dccp_rsk(req);
397         if (dccp_parse_options(sk, dreq, skb))
398                 goto drop_and_free;
399
400         if (security_inet_conn_request(sk, skb, req))
401                 goto drop_and_free;
402
403         ireq = inet_rsk(req);
404         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
405         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
406
407         if (ipv6_opt_accepted(sk, skb) ||
408             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
409             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
410                 atomic_inc(&skb->users);
411                 ireq->pktopts = skb;
412         }
413         ireq->ir_iif = sk->sk_bound_dev_if;
414
415         /* So that link locals have meaning */
416         if (!sk->sk_bound_dev_if &&
417             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
418                 ireq->ir_iif = inet6_iif(skb);
419
420         /*
421          * Step 3: Process LISTEN state
422          *
423          *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
424          *
425          * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
426          */
427         dreq->dreq_isr     = dcb->dccpd_seq;
428         dreq->dreq_gsr     = dreq->dreq_isr;
429         dreq->dreq_iss     = dccp_v6_init_sequence(skb);
430         dreq->dreq_gss     = dreq->dreq_iss;
431         dreq->dreq_service = service;
432
433         if (dccp_v6_send_response(sk, req))
434                 goto drop_and_free;
435
436         inet6_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
437         return 0;
438
439 drop_and_free:
440         reqsk_free(req);
441 drop:
442         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
443         return -1;
444 }
445
446 static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
447                                               struct sk_buff *skb,
448                                               struct request_sock *req,
449                                               struct dst_entry *dst)
450 {
451         struct inet_request_sock *ireq = inet_rsk(req);
452         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
453         struct inet_sock *newinet;
454         struct dccp6_sock *newdp6;
455         struct sock *newsk;
456
457         if (skb->protocol == htons(ETH_P_IP)) {
458                 /*
459                  *      v6 mapped
460                  */
461                 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst);
462                 if (newsk == NULL)
463                         return NULL;
464
465                 newdp6 = (struct dccp6_sock *)newsk;
466                 newinet = inet_sk(newsk);
467                 newinet->pinet6 = &newdp6->inet6;
468                 newnp = inet6_sk(newsk);
469
470                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
471
472                 ipv6_addr_set_v4mapped(newinet->inet_daddr, &newsk->sk_v6_daddr);
473
474                 ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
475
476                 newsk->sk_v6_rcv_saddr = newnp->saddr;
477
478                 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
479                 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
480                 newnp->pktoptions  = NULL;
481                 newnp->opt         = NULL;
482                 newnp->mcast_oif   = inet6_iif(skb);
483                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
484
485                 /*
486                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
487                  * here, dccp_create_openreq_child now does this for us, see the comment in
488                  * that function for the gory details. -acme
489                  */
490
491                 /* It is tricky place. Until this moment IPv4 tcp
492                    worked with IPv6 icsk.icsk_af_ops.
493                    Sync it now.
494                  */
495                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
496
497                 return newsk;
498         }
499
500
501         if (sk_acceptq_is_full(sk))
502                 goto out_overflow;
503
504         if (dst == NULL) {
505                 struct in6_addr *final_p, final;
506                 struct flowi6 fl6;
507
508                 memset(&fl6, 0, sizeof(fl6));
509                 fl6.flowi6_proto = IPPROTO_DCCP;
510                 fl6.daddr = ireq->ir_v6_rmt_addr;
511                 final_p = fl6_update_dst(&fl6, np->opt, &final);
512                 fl6.saddr = ireq->ir_v6_loc_addr;
513                 fl6.flowi6_oif = sk->sk_bound_dev_if;
514                 fl6.fl6_dport = ireq->ir_rmt_port;
515                 fl6.fl6_sport = htons(ireq->ir_num);
516                 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
517
518                 dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
519                 if (IS_ERR(dst))
520                         goto out;
521         }
522
523         newsk = dccp_create_openreq_child(sk, req, skb);
524         if (newsk == NULL)
525                 goto out_nonewsk;
526
527         /*
528          * No need to charge this sock to the relevant IPv6 refcnt debug socks
529          * count here, dccp_create_openreq_child now does this for us, see the
530          * comment in that function for the gory details. -acme
531          */
532
533         __ip6_dst_store(newsk, dst, NULL, NULL);
534         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
535                                                       NETIF_F_TSO);
536         newdp6 = (struct dccp6_sock *)newsk;
537         newinet = inet_sk(newsk);
538         newinet->pinet6 = &newdp6->inet6;
539         newnp = inet6_sk(newsk);
540
541         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
542
543         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
544         newnp->saddr            = ireq->ir_v6_loc_addr;
545         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
546         newsk->sk_bound_dev_if  = ireq->ir_iif;
547
548         /* Now IPv6 options...
549
550            First: no IPv4 options.
551          */
552         newinet->inet_opt = NULL;
553
554         /* Clone RX bits */
555         newnp->rxopt.all = np->rxopt.all;
556
557         /* Clone pktoptions received with SYN */
558         newnp->pktoptions = NULL;
559         if (ireq->pktopts != NULL) {
560                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
561                 consume_skb(ireq->pktopts);
562                 ireq->pktopts = NULL;
563                 if (newnp->pktoptions)
564                         skb_set_owner_r(newnp->pktoptions, newsk);
565         }
566         newnp->opt        = NULL;
567         newnp->mcast_oif  = inet6_iif(skb);
568         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
569
570         /*
571          * Clone native IPv6 options from listening socket (if any)
572          *
573          * Yes, keeping reference count would be much more clever, but we make
574          * one more one thing there: reattach optmem to newsk.
575          */
576         if (np->opt != NULL)
577                 newnp->opt = ipv6_dup_options(newsk, np->opt);
578
579         inet_csk(newsk)->icsk_ext_hdr_len = 0;
580         if (newnp->opt != NULL)
581                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
582                                                      newnp->opt->opt_flen);
583
584         dccp_sync_mss(newsk, dst_mtu(dst));
585
586         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
587         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
588
589         if (__inet_inherit_port(sk, newsk) < 0) {
590                 inet_csk_prepare_forced_close(newsk);
591                 dccp_done(newsk);
592                 goto out;
593         }
594         __inet6_hash(newsk, NULL);
595
596         return newsk;
597
598 out_overflow:
599         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
600 out_nonewsk:
601         dst_release(dst);
602 out:
603         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
604         return NULL;
605 }
606
607 /* The socket must have it's spinlock held when we get
608  * here.
609  *
610  * We have a potential double-lock case here, so even when
611  * doing backlog processing we use the BH locking scheme.
612  * This is because we cannot sleep with the original spinlock
613  * held.
614  */
615 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
616 {
617         struct ipv6_pinfo *np = inet6_sk(sk);
618         struct sk_buff *opt_skb = NULL;
619
620         /* Imagine: socket is IPv6. IPv4 packet arrives,
621            goes to IPv4 receive handler and backlogged.
622            From backlog it always goes here. Kerboom...
623            Fortunately, dccp_rcv_established and rcv_established
624            handle them correctly, but it is not case with
625            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
626          */
627
628         if (skb->protocol == htons(ETH_P_IP))
629                 return dccp_v4_do_rcv(sk, skb);
630
631         if (sk_filter(sk, skb))
632                 goto discard;
633
634         /*
635          * socket locking is here for SMP purposes as backlog rcv is currently
636          * called with bh processing disabled.
637          */
638
639         /* Do Stevens' IPV6_PKTOPTIONS.
640
641            Yes, guys, it is the only place in our code, where we
642            may make it not affecting IPv4.
643            The rest of code is protocol independent,
644            and I do not like idea to uglify IPv4.
645
646            Actually, all the idea behind IPV6_PKTOPTIONS
647            looks not very well thought. For now we latch
648            options, received in the last packet, enqueued
649            by tcp. Feel free to propose better solution.
650                                                --ANK (980728)
651          */
652         if (np->rxopt.all)
653         /*
654          * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
655          *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
656          */
657                 opt_skb = skb_clone(skb, GFP_ATOMIC);
658
659         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
660                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
661                         goto reset;
662                 if (opt_skb) {
663                         /* XXX This is where we would goto ipv6_pktoptions. */
664                         __kfree_skb(opt_skb);
665                 }
666                 return 0;
667         }
668
669         /*
670          *  Step 3: Process LISTEN state
671          *     If S.state == LISTEN,
672          *       If P.type == Request or P contains a valid Init Cookie option,
673          *            (* Must scan the packet's options to check for Init
674          *               Cookies.  Only Init Cookies are processed here,
675          *               however; other options are processed in Step 8.  This
676          *               scan need only be performed if the endpoint uses Init
677          *               Cookies *)
678          *            (* Generate a new socket and switch to that socket *)
679          *            Set S := new socket for this port pair
680          *            S.state = RESPOND
681          *            Choose S.ISS (initial seqno) or set from Init Cookies
682          *            Initialize S.GAR := S.ISS
683          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
684          *            Continue with S.state == RESPOND
685          *            (* A Response packet will be generated in Step 11 *)
686          *       Otherwise,
687          *            Generate Reset(No Connection) unless P.type == Reset
688          *            Drop packet and return
689          *
690          * NOTE: the check for the packet types is done in
691          *       dccp_rcv_state_process
692          */
693         if (sk->sk_state == DCCP_LISTEN) {
694                 struct sock *nsk = dccp_v6_hnd_req(sk, skb);
695
696                 if (nsk == NULL)
697                         goto discard;
698                 /*
699                  * Queue it on the new socket if the new socket is active,
700                  * otherwise we just shortcircuit this and continue with
701                  * the new socket..
702                  */
703                 if (nsk != sk) {
704                         if (dccp_child_process(sk, nsk, skb))
705                                 goto reset;
706                         if (opt_skb != NULL)
707                                 __kfree_skb(opt_skb);
708                         return 0;
709                 }
710         }
711
712         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
713                 goto reset;
714         if (opt_skb) {
715                 /* XXX This is where we would goto ipv6_pktoptions. */
716                 __kfree_skb(opt_skb);
717         }
718         return 0;
719
720 reset:
721         dccp_v6_ctl_send_reset(sk, skb);
722 discard:
723         if (opt_skb != NULL)
724                 __kfree_skb(opt_skb);
725         kfree_skb(skb);
726         return 0;
727 }
728
729 static int dccp_v6_rcv(struct sk_buff *skb)
730 {
731         const struct dccp_hdr *dh;
732         struct sock *sk;
733         int min_cov;
734
735         /* Step 1: Check header basics */
736
737         if (dccp_invalid_packet(skb))
738                 goto discard_it;
739
740         /* Step 1: If header checksum is incorrect, drop packet and return. */
741         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
742                                      &ipv6_hdr(skb)->daddr)) {
743                 DCCP_WARN("dropped packet with invalid checksum\n");
744                 goto discard_it;
745         }
746
747         dh = dccp_hdr(skb);
748
749         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
750         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
751
752         if (dccp_packet_without_ack(skb))
753                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
754         else
755                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
756
757         /* Step 2:
758          *      Look up flow ID in table and get corresponding socket */
759         sk = __inet6_lookup_skb(&dccp_hashinfo, skb,
760                                 dh->dccph_sport, dh->dccph_dport);
761         /*
762          * Step 2:
763          *      If no socket ...
764          */
765         if (sk == NULL) {
766                 dccp_pr_debug("failed to look up flow ID in table and "
767                               "get corresponding socket\n");
768                 goto no_dccp_socket;
769         }
770
771         /*
772          * Step 2:
773          *      ... or S.state == TIMEWAIT,
774          *              Generate Reset(No Connection) unless P.type == Reset
775          *              Drop packet and return
776          */
777         if (sk->sk_state == DCCP_TIME_WAIT) {
778                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
779                 inet_twsk_put(inet_twsk(sk));
780                 goto no_dccp_socket;
781         }
782
783         /*
784          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
785          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
786          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
787          */
788         min_cov = dccp_sk(sk)->dccps_pcrlen;
789         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
790                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
791                               dh->dccph_cscov, min_cov);
792                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
793                 goto discard_and_relse;
794         }
795
796         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
797                 goto discard_and_relse;
798
799         return sk_receive_skb(sk, skb, 1) ? -1 : 0;
800
801 no_dccp_socket:
802         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
803                 goto discard_it;
804         /*
805          * Step 2:
806          *      If no socket ...
807          *              Generate Reset(No Connection) unless P.type == Reset
808          *              Drop packet and return
809          */
810         if (dh->dccph_type != DCCP_PKT_RESET) {
811                 DCCP_SKB_CB(skb)->dccpd_reset_code =
812                                         DCCP_RESET_CODE_NO_CONNECTION;
813                 dccp_v6_ctl_send_reset(sk, skb);
814         }
815
816 discard_it:
817         kfree_skb(skb);
818         return 0;
819
820 discard_and_relse:
821         sock_put(sk);
822         goto discard_it;
823 }
824
825 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
826                            int addr_len)
827 {
828         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
829         struct inet_connection_sock *icsk = inet_csk(sk);
830         struct inet_sock *inet = inet_sk(sk);
831         struct ipv6_pinfo *np = inet6_sk(sk);
832         struct dccp_sock *dp = dccp_sk(sk);
833         struct in6_addr *saddr = NULL, *final_p, final;
834         struct flowi6 fl6;
835         struct dst_entry *dst;
836         int addr_type;
837         int err;
838
839         dp->dccps_role = DCCP_ROLE_CLIENT;
840
841         if (addr_len < SIN6_LEN_RFC2133)
842                 return -EINVAL;
843
844         if (usin->sin6_family != AF_INET6)
845                 return -EAFNOSUPPORT;
846
847         memset(&fl6, 0, sizeof(fl6));
848
849         if (np->sndflow) {
850                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
851                 IP6_ECN_flow_init(fl6.flowlabel);
852                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
853                         struct ip6_flowlabel *flowlabel;
854                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
855                         if (flowlabel == NULL)
856                                 return -EINVAL;
857                         fl6_sock_release(flowlabel);
858                 }
859         }
860         /*
861          * connect() to INADDR_ANY means loopback (BSD'ism).
862          */
863         if (ipv6_addr_any(&usin->sin6_addr))
864                 usin->sin6_addr.s6_addr[15] = 1;
865
866         addr_type = ipv6_addr_type(&usin->sin6_addr);
867
868         if (addr_type & IPV6_ADDR_MULTICAST)
869                 return -ENETUNREACH;
870
871         if (addr_type & IPV6_ADDR_LINKLOCAL) {
872                 if (addr_len >= sizeof(struct sockaddr_in6) &&
873                     usin->sin6_scope_id) {
874                         /* If interface is set while binding, indices
875                          * must coincide.
876                          */
877                         if (sk->sk_bound_dev_if &&
878                             sk->sk_bound_dev_if != usin->sin6_scope_id)
879                                 return -EINVAL;
880
881                         sk->sk_bound_dev_if = usin->sin6_scope_id;
882                 }
883
884                 /* Connect to link-local address requires an interface */
885                 if (!sk->sk_bound_dev_if)
886                         return -EINVAL;
887         }
888
889         sk->sk_v6_daddr = usin->sin6_addr;
890         np->flow_label = fl6.flowlabel;
891
892         /*
893          * DCCP over IPv4
894          */
895         if (addr_type == IPV6_ADDR_MAPPED) {
896                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
897                 struct sockaddr_in sin;
898
899                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
900
901                 if (__ipv6_only_sock(sk))
902                         return -ENETUNREACH;
903
904                 sin.sin_family = AF_INET;
905                 sin.sin_port = usin->sin6_port;
906                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
907
908                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
909                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
910
911                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
912                 if (err) {
913                         icsk->icsk_ext_hdr_len = exthdrlen;
914                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
915                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
916                         goto failure;
917                 }
918                 ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
919                 ipv6_addr_set_v4mapped(inet->inet_rcv_saddr, &sk->sk_v6_rcv_saddr);
920
921                 return err;
922         }
923
924         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
925                 saddr = &sk->sk_v6_rcv_saddr;
926
927         fl6.flowi6_proto = IPPROTO_DCCP;
928         fl6.daddr = sk->sk_v6_daddr;
929         fl6.saddr = saddr ? *saddr : np->saddr;
930         fl6.flowi6_oif = sk->sk_bound_dev_if;
931         fl6.fl6_dport = usin->sin6_port;
932         fl6.fl6_sport = inet->inet_sport;
933         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
934
935         final_p = fl6_update_dst(&fl6, np->opt, &final);
936
937         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
938         if (IS_ERR(dst)) {
939                 err = PTR_ERR(dst);
940                 goto failure;
941         }
942
943         if (saddr == NULL) {
944                 saddr = &fl6.saddr;
945                 sk->sk_v6_rcv_saddr = *saddr;
946         }
947
948         /* set the source address */
949         np->saddr = *saddr;
950         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
951
952         __ip6_dst_store(sk, dst, NULL, NULL);
953
954         icsk->icsk_ext_hdr_len = 0;
955         if (np->opt != NULL)
956                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
957                                           np->opt->opt_nflen);
958
959         inet->inet_dport = usin->sin6_port;
960
961         dccp_set_state(sk, DCCP_REQUESTING);
962         err = inet6_hash_connect(&dccp_death_row, sk);
963         if (err)
964                 goto late_failure;
965
966         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
967                                                       sk->sk_v6_daddr.s6_addr32,
968                                                       inet->inet_sport,
969                                                       inet->inet_dport);
970         err = dccp_connect(sk);
971         if (err)
972                 goto late_failure;
973
974         return 0;
975
976 late_failure:
977         dccp_set_state(sk, DCCP_CLOSED);
978         __sk_dst_reset(sk);
979 failure:
980         inet->inet_dport = 0;
981         sk->sk_route_caps = 0;
982         return err;
983 }
984
985 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
986         .queue_xmit        = inet6_csk_xmit,
987         .send_check        = dccp_v6_send_check,
988         .rebuild_header    = inet6_sk_rebuild_header,
989         .conn_request      = dccp_v6_conn_request,
990         .syn_recv_sock     = dccp_v6_request_recv_sock,
991         .net_header_len    = sizeof(struct ipv6hdr),
992         .setsockopt        = ipv6_setsockopt,
993         .getsockopt        = ipv6_getsockopt,
994         .addr2sockaddr     = inet6_csk_addr2sockaddr,
995         .sockaddr_len      = sizeof(struct sockaddr_in6),
996         .bind_conflict     = inet6_csk_bind_conflict,
997 #ifdef CONFIG_COMPAT
998         .compat_setsockopt = compat_ipv6_setsockopt,
999         .compat_getsockopt = compat_ipv6_getsockopt,
1000 #endif
1001 };
1002
1003 /*
1004  *      DCCP over IPv4 via INET6 API
1005  */
1006 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
1007         .queue_xmit        = ip_queue_xmit,
1008         .send_check        = dccp_v4_send_check,
1009         .rebuild_header    = inet_sk_rebuild_header,
1010         .conn_request      = dccp_v6_conn_request,
1011         .syn_recv_sock     = dccp_v6_request_recv_sock,
1012         .net_header_len    = sizeof(struct iphdr),
1013         .setsockopt        = ipv6_setsockopt,
1014         .getsockopt        = ipv6_getsockopt,
1015         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1016         .sockaddr_len      = sizeof(struct sockaddr_in6),
1017 #ifdef CONFIG_COMPAT
1018         .compat_setsockopt = compat_ipv6_setsockopt,
1019         .compat_getsockopt = compat_ipv6_getsockopt,
1020 #endif
1021 };
1022
1023 /* NOTE: A lot of things set to zero explicitly by call to
1024  *       sk_alloc() so need not be done here.
1025  */
1026 static int dccp_v6_init_sock(struct sock *sk)
1027 {
1028         static __u8 dccp_v6_ctl_sock_initialized;
1029         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
1030
1031         if (err == 0) {
1032                 if (unlikely(!dccp_v6_ctl_sock_initialized))
1033                         dccp_v6_ctl_sock_initialized = 1;
1034                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
1035         }
1036
1037         return err;
1038 }
1039
1040 static void dccp_v6_destroy_sock(struct sock *sk)
1041 {
1042         dccp_destroy_sock(sk);
1043         inet6_destroy_sock(sk);
1044 }
1045
1046 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
1047         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
1048 };
1049
1050 static struct proto dccp_v6_prot = {
1051         .name              = "DCCPv6",
1052         .owner             = THIS_MODULE,
1053         .close             = dccp_close,
1054         .connect           = dccp_v6_connect,
1055         .disconnect        = dccp_disconnect,
1056         .ioctl             = dccp_ioctl,
1057         .init              = dccp_v6_init_sock,
1058         .setsockopt        = dccp_setsockopt,
1059         .getsockopt        = dccp_getsockopt,
1060         .sendmsg           = dccp_sendmsg,
1061         .recvmsg           = dccp_recvmsg,
1062         .backlog_rcv       = dccp_v6_do_rcv,
1063         .hash              = dccp_v6_hash,
1064         .unhash            = inet_unhash,
1065         .accept            = inet_csk_accept,
1066         .get_port          = inet_csk_get_port,
1067         .shutdown          = dccp_shutdown,
1068         .destroy           = dccp_v6_destroy_sock,
1069         .orphan_count      = &dccp_orphan_count,
1070         .max_header        = MAX_DCCP_HEADER,
1071         .obj_size          = sizeof(struct dccp6_sock),
1072         .slab_flags        = SLAB_DESTROY_BY_RCU,
1073         .rsk_prot          = &dccp6_request_sock_ops,
1074         .twsk_prot         = &dccp6_timewait_sock_ops,
1075         .h.hashinfo        = &dccp_hashinfo,
1076 #ifdef CONFIG_COMPAT
1077         .compat_setsockopt = compat_dccp_setsockopt,
1078         .compat_getsockopt = compat_dccp_getsockopt,
1079 #endif
1080 };
1081
1082 static const struct inet6_protocol dccp_v6_protocol = {
1083         .handler        = dccp_v6_rcv,
1084         .err_handler    = dccp_v6_err,
1085         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1086 };
1087
1088 static const struct proto_ops inet6_dccp_ops = {
1089         .family            = PF_INET6,
1090         .owner             = THIS_MODULE,
1091         .release           = inet6_release,
1092         .bind              = inet6_bind,
1093         .connect           = inet_stream_connect,
1094         .socketpair        = sock_no_socketpair,
1095         .accept            = inet_accept,
1096         .getname           = inet6_getname,
1097         .poll              = dccp_poll,
1098         .ioctl             = inet6_ioctl,
1099         .listen            = inet_dccp_listen,
1100         .shutdown          = inet_shutdown,
1101         .setsockopt        = sock_common_setsockopt,
1102         .getsockopt        = sock_common_getsockopt,
1103         .sendmsg           = inet_sendmsg,
1104         .recvmsg           = sock_common_recvmsg,
1105         .mmap              = sock_no_mmap,
1106         .sendpage          = sock_no_sendpage,
1107 #ifdef CONFIG_COMPAT
1108         .compat_setsockopt = compat_sock_common_setsockopt,
1109         .compat_getsockopt = compat_sock_common_getsockopt,
1110 #endif
1111 };
1112
1113 static struct inet_protosw dccp_v6_protosw = {
1114         .type           = SOCK_DCCP,
1115         .protocol       = IPPROTO_DCCP,
1116         .prot           = &dccp_v6_prot,
1117         .ops            = &inet6_dccp_ops,
1118         .flags          = INET_PROTOSW_ICSK,
1119 };
1120
1121 static int __net_init dccp_v6_init_net(struct net *net)
1122 {
1123         if (dccp_hashinfo.bhash == NULL)
1124                 return -ESOCKTNOSUPPORT;
1125
1126         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1127                                     SOCK_DCCP, IPPROTO_DCCP, net);
1128 }
1129
1130 static void __net_exit dccp_v6_exit_net(struct net *net)
1131 {
1132         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1133 }
1134
1135 static struct pernet_operations dccp_v6_ops = {
1136         .init   = dccp_v6_init_net,
1137         .exit   = dccp_v6_exit_net,
1138 };
1139
1140 static int __init dccp_v6_init(void)
1141 {
1142         int err = proto_register(&dccp_v6_prot, 1);
1143
1144         if (err != 0)
1145                 goto out;
1146
1147         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1148         if (err != 0)
1149                 goto out_unregister_proto;
1150
1151         inet6_register_protosw(&dccp_v6_protosw);
1152
1153         err = register_pernet_subsys(&dccp_v6_ops);
1154         if (err != 0)
1155                 goto out_destroy_ctl_sock;
1156 out:
1157         return err;
1158
1159 out_destroy_ctl_sock:
1160         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1161         inet6_unregister_protosw(&dccp_v6_protosw);
1162 out_unregister_proto:
1163         proto_unregister(&dccp_v6_prot);
1164         goto out;
1165 }
1166
1167 static void __exit dccp_v6_exit(void)
1168 {
1169         unregister_pernet_subsys(&dccp_v6_ops);
1170         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1171         inet6_unregister_protosw(&dccp_v6_protosw);
1172         proto_unregister(&dccp_v6_prot);
1173 }
1174
1175 module_init(dccp_v6_init);
1176 module_exit(dccp_v6_exit);
1177
1178 /*
1179  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1180  * values directly, Also cover the case where the protocol is not specified,
1181  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1182  */
1183 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1184 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1185 MODULE_LICENSE("GPL");
1186 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1187 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");