Merge tag 'nds32-for-linus-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-microblaze.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 #include <linux/string.h>
20
21 #include <net/addrconf.h>
22 #include <net/inet_common.h>
23 #include <net/inet_hashtables.h>
24 #include <net/inet_sock.h>
25 #include <net/inet6_connection_sock.h>
26 #include <net/inet6_hashtables.h>
27 #include <net/ip6_route.h>
28 #include <net/ipv6.h>
29 #include <net/protocol.h>
30 #include <net/transp_v6.h>
31 #include <net/ip6_checksum.h>
32 #include <net/xfrm.h>
33 #include <net/secure_seq.h>
34 #include <net/sock.h>
35
36 #include "dccp.h"
37 #include "ipv6.h"
38 #include "feat.h"
39
40 /* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */
41
42 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
43 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
44
45 /* add pseudo-header to DCCP checksum stored in skb->csum */
46 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
47                                       const struct in6_addr *saddr,
48                                       const struct in6_addr *daddr)
49 {
50         return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
51 }
52
53 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
54 {
55         struct ipv6_pinfo *np = inet6_sk(sk);
56         struct dccp_hdr *dh = dccp_hdr(skb);
57
58         dccp_csum_outgoing(skb);
59         dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
60 }
61
62 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
63 {
64         return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
65                                              ipv6_hdr(skb)->saddr.s6_addr32,
66                                              dccp_hdr(skb)->dccph_dport,
67                                              dccp_hdr(skb)->dccph_sport     );
68
69 }
70
71 static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
72                         u8 type, u8 code, int offset, __be32 info)
73 {
74         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
75         const struct dccp_hdr *dh;
76         struct dccp_sock *dp;
77         struct ipv6_pinfo *np;
78         struct sock *sk;
79         int err;
80         __u64 seq;
81         struct net *net = dev_net(skb->dev);
82
83         /* Only need dccph_dport & dccph_sport which are the first
84          * 4 bytes in dccp header.
85          * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
86          */
87         BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
88         BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
89         dh = (struct dccp_hdr *)(skb->data + offset);
90
91         sk = __inet6_lookup_established(net, &dccp_hashinfo,
92                                         &hdr->daddr, dh->dccph_dport,
93                                         &hdr->saddr, ntohs(dh->dccph_sport),
94                                         inet6_iif(skb), 0);
95
96         if (!sk) {
97                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
98                                   ICMP6_MIB_INERRORS);
99                 return;
100         }
101
102         if (sk->sk_state == DCCP_TIME_WAIT) {
103                 inet_twsk_put(inet_twsk(sk));
104                 return;
105         }
106         seq = dccp_hdr_seq(dh);
107         if (sk->sk_state == DCCP_NEW_SYN_RECV)
108                 return dccp_req_err(sk, seq);
109
110         bh_lock_sock(sk);
111         if (sock_owned_by_user(sk))
112                 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
113
114         if (sk->sk_state == DCCP_CLOSED)
115                 goto out;
116
117         dp = dccp_sk(sk);
118         if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
119             !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
120                 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
121                 goto out;
122         }
123
124         np = inet6_sk(sk);
125
126         if (type == NDISC_REDIRECT) {
127                 if (!sock_owned_by_user(sk)) {
128                         struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
129
130                         if (dst)
131                                 dst->ops->redirect(dst, sk, skb);
132                 }
133                 goto out;
134         }
135
136         if (type == ICMPV6_PKT_TOOBIG) {
137                 struct dst_entry *dst = NULL;
138
139                 if (!ip6_sk_accept_pmtu(sk))
140                         goto out;
141
142                 if (sock_owned_by_user(sk))
143                         goto out;
144                 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
145                         goto out;
146
147                 dst = inet6_csk_update_pmtu(sk, ntohl(info));
148                 if (!dst)
149                         goto out;
150
151                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
152                         dccp_sync_mss(sk, dst_mtu(dst));
153                 goto out;
154         }
155
156         icmpv6_err_convert(type, code, &err);
157
158         /* Might be for an request_sock */
159         switch (sk->sk_state) {
160         case DCCP_REQUESTING:
161         case DCCP_RESPOND:  /* Cannot happen.
162                                It can, it SYNs are crossed. --ANK */
163                 if (!sock_owned_by_user(sk)) {
164                         __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
165                         sk->sk_err = err;
166                         /*
167                          * Wake people up to see the error
168                          * (see connect in sock.c)
169                          */
170                         sk->sk_error_report(sk);
171                         dccp_done(sk);
172                 } else
173                         sk->sk_err_soft = err;
174                 goto out;
175         }
176
177         if (!sock_owned_by_user(sk) && np->recverr) {
178                 sk->sk_err = err;
179                 sk->sk_error_report(sk);
180         } else
181                 sk->sk_err_soft = err;
182
183 out:
184         bh_unlock_sock(sk);
185         sock_put(sk);
186 }
187
188
189 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
190 {
191         struct inet_request_sock *ireq = inet_rsk(req);
192         struct ipv6_pinfo *np = inet6_sk(sk);
193         struct sk_buff *skb;
194         struct in6_addr *final_p, final;
195         struct flowi6 fl6;
196         int err = -1;
197         struct dst_entry *dst;
198
199         memset(&fl6, 0, sizeof(fl6));
200         fl6.flowi6_proto = IPPROTO_DCCP;
201         fl6.daddr = ireq->ir_v6_rmt_addr;
202         fl6.saddr = ireq->ir_v6_loc_addr;
203         fl6.flowlabel = 0;
204         fl6.flowi6_oif = ireq->ir_iif;
205         fl6.fl6_dport = ireq->ir_rmt_port;
206         fl6.fl6_sport = htons(ireq->ir_num);
207         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
208
209
210         rcu_read_lock();
211         final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
212         rcu_read_unlock();
213
214         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
215         if (IS_ERR(dst)) {
216                 err = PTR_ERR(dst);
217                 dst = NULL;
218                 goto done;
219         }
220
221         skb = dccp_make_response(sk, dst, req);
222         if (skb != NULL) {
223                 struct dccp_hdr *dh = dccp_hdr(skb);
224                 struct ipv6_txoptions *opt;
225
226                 dh->dccph_checksum = dccp_v6_csum_finish(skb,
227                                                          &ireq->ir_v6_loc_addr,
228                                                          &ireq->ir_v6_rmt_addr);
229                 fl6.daddr = ireq->ir_v6_rmt_addr;
230                 rcu_read_lock();
231                 opt = ireq->ipv6_opt;
232                 if (!opt)
233                         opt = rcu_dereference(np->opt);
234                 err = ip6_xmit(sk, skb, &fl6, sk->sk_mark, opt, np->tclass);
235                 rcu_read_unlock();
236                 err = net_xmit_eval(err);
237         }
238
239 done:
240         dst_release(dst);
241         return err;
242 }
243
244 static void dccp_v6_reqsk_destructor(struct request_sock *req)
245 {
246         dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
247         kfree(inet_rsk(req)->ipv6_opt);
248         kfree_skb(inet_rsk(req)->pktopts);
249 }
250
251 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
252 {
253         const struct ipv6hdr *rxip6h;
254         struct sk_buff *skb;
255         struct flowi6 fl6;
256         struct net *net = dev_net(skb_dst(rxskb)->dev);
257         struct sock *ctl_sk = net->dccp.v6_ctl_sk;
258         struct dst_entry *dst;
259
260         if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
261                 return;
262
263         if (!ipv6_unicast_destination(rxskb))
264                 return;
265
266         skb = dccp_ctl_make_reset(ctl_sk, rxskb);
267         if (skb == NULL)
268                 return;
269
270         rxip6h = ipv6_hdr(rxskb);
271         dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
272                                                             &rxip6h->daddr);
273
274         memset(&fl6, 0, sizeof(fl6));
275         fl6.daddr = rxip6h->saddr;
276         fl6.saddr = rxip6h->daddr;
277
278         fl6.flowi6_proto = IPPROTO_DCCP;
279         fl6.flowi6_oif = inet6_iif(rxskb);
280         fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
281         fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
282         security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
283
284         /* sk = NULL, but it is safe for now. RST socket required. */
285         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
286         if (!IS_ERR(dst)) {
287                 skb_dst_set(skb, dst);
288                 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0);
289                 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
290                 DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
291                 return;
292         }
293
294         kfree_skb(skb);
295 }
296
297 static struct request_sock_ops dccp6_request_sock_ops = {
298         .family         = AF_INET6,
299         .obj_size       = sizeof(struct dccp6_request_sock),
300         .rtx_syn_ack    = dccp_v6_send_response,
301         .send_ack       = dccp_reqsk_send_ack,
302         .destructor     = dccp_v6_reqsk_destructor,
303         .send_reset     = dccp_v6_ctl_send_reset,
304         .syn_ack_timeout = dccp_syn_ack_timeout,
305 };
306
307 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
308 {
309         struct request_sock *req;
310         struct dccp_request_sock *dreq;
311         struct inet_request_sock *ireq;
312         struct ipv6_pinfo *np = inet6_sk(sk);
313         const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
314         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
315
316         if (skb->protocol == htons(ETH_P_IP))
317                 return dccp_v4_conn_request(sk, skb);
318
319         if (!ipv6_unicast_destination(skb))
320                 return 0;       /* discard, don't send a reset here */
321
322         if (dccp_bad_service_code(sk, service)) {
323                 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
324                 goto drop;
325         }
326         /*
327          * There are no SYN attacks on IPv6, yet...
328          */
329         dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
330         if (inet_csk_reqsk_queue_is_full(sk))
331                 goto drop;
332
333         if (sk_acceptq_is_full(sk))
334                 goto drop;
335
336         req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
337         if (req == NULL)
338                 goto drop;
339
340         if (dccp_reqsk_init(req, dccp_sk(sk), skb))
341                 goto drop_and_free;
342
343         dreq = dccp_rsk(req);
344         if (dccp_parse_options(sk, dreq, skb))
345                 goto drop_and_free;
346
347         if (security_inet_conn_request(sk, skb, req))
348                 goto drop_and_free;
349
350         ireq = inet_rsk(req);
351         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
352         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
353         ireq->ireq_family = AF_INET6;
354         ireq->ir_mark = inet_request_mark(sk, skb);
355
356         if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
357             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
358             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
359                 refcount_inc(&skb->users);
360                 ireq->pktopts = skb;
361         }
362         ireq->ir_iif = sk->sk_bound_dev_if;
363
364         /* So that link locals have meaning */
365         if (!sk->sk_bound_dev_if &&
366             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
367                 ireq->ir_iif = inet6_iif(skb);
368
369         /*
370          * Step 3: Process LISTEN state
371          *
372          *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
373          *
374          * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
375          */
376         dreq->dreq_isr     = dcb->dccpd_seq;
377         dreq->dreq_gsr     = dreq->dreq_isr;
378         dreq->dreq_iss     = dccp_v6_init_sequence(skb);
379         dreq->dreq_gss     = dreq->dreq_iss;
380         dreq->dreq_service = service;
381
382         if (dccp_v6_send_response(sk, req))
383                 goto drop_and_free;
384
385         inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
386         reqsk_put(req);
387         return 0;
388
389 drop_and_free:
390         reqsk_free(req);
391 drop:
392         __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
393         return -1;
394 }
395
396 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
397                                               struct sk_buff *skb,
398                                               struct request_sock *req,
399                                               struct dst_entry *dst,
400                                               struct request_sock *req_unhash,
401                                               bool *own_req)
402 {
403         struct inet_request_sock *ireq = inet_rsk(req);
404         struct ipv6_pinfo *newnp;
405         const struct ipv6_pinfo *np = inet6_sk(sk);
406         struct ipv6_txoptions *opt;
407         struct inet_sock *newinet;
408         struct dccp6_sock *newdp6;
409         struct sock *newsk;
410
411         if (skb->protocol == htons(ETH_P_IP)) {
412                 /*
413                  *      v6 mapped
414                  */
415                 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
416                                                   req_unhash, own_req);
417                 if (newsk == NULL)
418                         return NULL;
419
420                 newdp6 = (struct dccp6_sock *)newsk;
421                 newinet = inet_sk(newsk);
422                 newinet->pinet6 = &newdp6->inet6;
423                 newnp = inet6_sk(newsk);
424
425                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
426
427                 newnp->saddr = newsk->sk_v6_rcv_saddr;
428
429                 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
430                 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
431                 newnp->pktoptions  = NULL;
432                 newnp->opt         = NULL;
433                 newnp->ipv6_mc_list = NULL;
434                 newnp->ipv6_ac_list = NULL;
435                 newnp->ipv6_fl_list = NULL;
436                 newnp->mcast_oif   = inet6_iif(skb);
437                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
438
439                 /*
440                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
441                  * here, dccp_create_openreq_child now does this for us, see the comment in
442                  * that function for the gory details. -acme
443                  */
444
445                 /* It is tricky place. Until this moment IPv4 tcp
446                    worked with IPv6 icsk.icsk_af_ops.
447                    Sync it now.
448                  */
449                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
450
451                 return newsk;
452         }
453
454
455         if (sk_acceptq_is_full(sk))
456                 goto out_overflow;
457
458         if (!dst) {
459                 struct flowi6 fl6;
460
461                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
462                 if (!dst)
463                         goto out;
464         }
465
466         newsk = dccp_create_openreq_child(sk, req, skb);
467         if (newsk == NULL)
468                 goto out_nonewsk;
469
470         /*
471          * No need to charge this sock to the relevant IPv6 refcnt debug socks
472          * count here, dccp_create_openreq_child now does this for us, see the
473          * comment in that function for the gory details. -acme
474          */
475
476         ip6_dst_store(newsk, dst, NULL, NULL);
477         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
478                                                       NETIF_F_TSO);
479         newdp6 = (struct dccp6_sock *)newsk;
480         newinet = inet_sk(newsk);
481         newinet->pinet6 = &newdp6->inet6;
482         newnp = inet6_sk(newsk);
483
484         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
485
486         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
487         newnp->saddr            = ireq->ir_v6_loc_addr;
488         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
489         newsk->sk_bound_dev_if  = ireq->ir_iif;
490
491         /* Now IPv6 options...
492
493            First: no IPv4 options.
494          */
495         newinet->inet_opt = NULL;
496
497         /* Clone RX bits */
498         newnp->rxopt.all = np->rxopt.all;
499
500         newnp->ipv6_mc_list = NULL;
501         newnp->ipv6_ac_list = NULL;
502         newnp->ipv6_fl_list = NULL;
503         newnp->pktoptions = NULL;
504         newnp->opt        = NULL;
505         newnp->mcast_oif  = inet6_iif(skb);
506         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
507
508         /*
509          * Clone native IPv6 options from listening socket (if any)
510          *
511          * Yes, keeping reference count would be much more clever, but we make
512          * one more one thing there: reattach optmem to newsk.
513          */
514         opt = ireq->ipv6_opt;
515         if (!opt)
516                 opt = rcu_dereference(np->opt);
517         if (opt) {
518                 opt = ipv6_dup_options(newsk, opt);
519                 RCU_INIT_POINTER(newnp->opt, opt);
520         }
521         inet_csk(newsk)->icsk_ext_hdr_len = 0;
522         if (opt)
523                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
524                                                     opt->opt_flen;
525
526         dccp_sync_mss(newsk, dst_mtu(dst));
527
528         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
529         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
530
531         if (__inet_inherit_port(sk, newsk) < 0) {
532                 inet_csk_prepare_forced_close(newsk);
533                 dccp_done(newsk);
534                 goto out;
535         }
536         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
537         /* Clone pktoptions received with SYN, if we own the req */
538         if (*own_req && ireq->pktopts) {
539                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
540                 consume_skb(ireq->pktopts);
541                 ireq->pktopts = NULL;
542                 if (newnp->pktoptions)
543                         skb_set_owner_r(newnp->pktoptions, newsk);
544         }
545
546         return newsk;
547
548 out_overflow:
549         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
550 out_nonewsk:
551         dst_release(dst);
552 out:
553         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
554         return NULL;
555 }
556
557 /* The socket must have it's spinlock held when we get
558  * here.
559  *
560  * We have a potential double-lock case here, so even when
561  * doing backlog processing we use the BH locking scheme.
562  * This is because we cannot sleep with the original spinlock
563  * held.
564  */
565 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
566 {
567         struct ipv6_pinfo *np = inet6_sk(sk);
568         struct sk_buff *opt_skb = NULL;
569
570         /* Imagine: socket is IPv6. IPv4 packet arrives,
571            goes to IPv4 receive handler and backlogged.
572            From backlog it always goes here. Kerboom...
573            Fortunately, dccp_rcv_established and rcv_established
574            handle them correctly, but it is not case with
575            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
576          */
577
578         if (skb->protocol == htons(ETH_P_IP))
579                 return dccp_v4_do_rcv(sk, skb);
580
581         if (sk_filter(sk, skb))
582                 goto discard;
583
584         /*
585          * socket locking is here for SMP purposes as backlog rcv is currently
586          * called with bh processing disabled.
587          */
588
589         /* Do Stevens' IPV6_PKTOPTIONS.
590
591            Yes, guys, it is the only place in our code, where we
592            may make it not affecting IPv4.
593            The rest of code is protocol independent,
594            and I do not like idea to uglify IPv4.
595
596            Actually, all the idea behind IPV6_PKTOPTIONS
597            looks not very well thought. For now we latch
598            options, received in the last packet, enqueued
599            by tcp. Feel free to propose better solution.
600                                                --ANK (980728)
601          */
602         if (np->rxopt.all)
603                 opt_skb = skb_clone(skb, GFP_ATOMIC);
604
605         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
606                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
607                         goto reset;
608                 if (opt_skb)
609                         goto ipv6_pktoptions;
610                 return 0;
611         }
612
613         /*
614          *  Step 3: Process LISTEN state
615          *     If S.state == LISTEN,
616          *       If P.type == Request or P contains a valid Init Cookie option,
617          *            (* Must scan the packet's options to check for Init
618          *               Cookies.  Only Init Cookies are processed here,
619          *               however; other options are processed in Step 8.  This
620          *               scan need only be performed if the endpoint uses Init
621          *               Cookies *)
622          *            (* Generate a new socket and switch to that socket *)
623          *            Set S := new socket for this port pair
624          *            S.state = RESPOND
625          *            Choose S.ISS (initial seqno) or set from Init Cookies
626          *            Initialize S.GAR := S.ISS
627          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
628          *            Continue with S.state == RESPOND
629          *            (* A Response packet will be generated in Step 11 *)
630          *       Otherwise,
631          *            Generate Reset(No Connection) unless P.type == Reset
632          *            Drop packet and return
633          *
634          * NOTE: the check for the packet types is done in
635          *       dccp_rcv_state_process
636          */
637
638         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
639                 goto reset;
640         if (opt_skb)
641                 goto ipv6_pktoptions;
642         return 0;
643
644 reset:
645         dccp_v6_ctl_send_reset(sk, skb);
646 discard:
647         if (opt_skb != NULL)
648                 __kfree_skb(opt_skb);
649         kfree_skb(skb);
650         return 0;
651
652 /* Handling IPV6_PKTOPTIONS skb the similar
653  * way it's done for net/ipv6/tcp_ipv6.c
654  */
655 ipv6_pktoptions:
656         if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) {
657                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
658                         np->mcast_oif = inet6_iif(opt_skb);
659                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
660                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
661                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
662                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
663                 if (np->repflow)
664                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
665                 if (ipv6_opt_accepted(sk, opt_skb,
666                                       &DCCP_SKB_CB(opt_skb)->header.h6)) {
667                         skb_set_owner_r(opt_skb, sk);
668                         memmove(IP6CB(opt_skb),
669                                 &DCCP_SKB_CB(opt_skb)->header.h6,
670                                 sizeof(struct inet6_skb_parm));
671                         opt_skb = xchg(&np->pktoptions, opt_skb);
672                 } else {
673                         __kfree_skb(opt_skb);
674                         opt_skb = xchg(&np->pktoptions, NULL);
675                 }
676         }
677
678         kfree_skb(opt_skb);
679         return 0;
680 }
681
682 static int dccp_v6_rcv(struct sk_buff *skb)
683 {
684         const struct dccp_hdr *dh;
685         bool refcounted;
686         struct sock *sk;
687         int min_cov;
688
689         /* Step 1: Check header basics */
690
691         if (dccp_invalid_packet(skb))
692                 goto discard_it;
693
694         /* Step 1: If header checksum is incorrect, drop packet and return. */
695         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
696                                      &ipv6_hdr(skb)->daddr)) {
697                 DCCP_WARN("dropped packet with invalid checksum\n");
698                 goto discard_it;
699         }
700
701         dh = dccp_hdr(skb);
702
703         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
704         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
705
706         if (dccp_packet_without_ack(skb))
707                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
708         else
709                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
710
711 lookup:
712         sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
713                                 dh->dccph_sport, dh->dccph_dport,
714                                 inet6_iif(skb), 0, &refcounted);
715         if (!sk) {
716                 dccp_pr_debug("failed to look up flow ID in table and "
717                               "get corresponding socket\n");
718                 goto no_dccp_socket;
719         }
720
721         /*
722          * Step 2:
723          *      ... or S.state == TIMEWAIT,
724          *              Generate Reset(No Connection) unless P.type == Reset
725          *              Drop packet and return
726          */
727         if (sk->sk_state == DCCP_TIME_WAIT) {
728                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
729                 inet_twsk_put(inet_twsk(sk));
730                 goto no_dccp_socket;
731         }
732
733         if (sk->sk_state == DCCP_NEW_SYN_RECV) {
734                 struct request_sock *req = inet_reqsk(sk);
735                 struct sock *nsk;
736
737                 sk = req->rsk_listener;
738                 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
739                         inet_csk_reqsk_queue_drop_and_put(sk, req);
740                         goto lookup;
741                 }
742                 sock_hold(sk);
743                 refcounted = true;
744                 nsk = dccp_check_req(sk, skb, req);
745                 if (!nsk) {
746                         reqsk_put(req);
747                         goto discard_and_relse;
748                 }
749                 if (nsk == sk) {
750                         reqsk_put(req);
751                 } else if (dccp_child_process(sk, nsk, skb)) {
752                         dccp_v6_ctl_send_reset(sk, skb);
753                         goto discard_and_relse;
754                 } else {
755                         sock_put(sk);
756                         return 0;
757                 }
758         }
759         /*
760          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
761          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
762          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
763          */
764         min_cov = dccp_sk(sk)->dccps_pcrlen;
765         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
766                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
767                               dh->dccph_cscov, min_cov);
768                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
769                 goto discard_and_relse;
770         }
771
772         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
773                 goto discard_and_relse;
774
775         return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4,
776                                 refcounted) ? -1 : 0;
777
778 no_dccp_socket:
779         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
780                 goto discard_it;
781         /*
782          * Step 2:
783          *      If no socket ...
784          *              Generate Reset(No Connection) unless P.type == Reset
785          *              Drop packet and return
786          */
787         if (dh->dccph_type != DCCP_PKT_RESET) {
788                 DCCP_SKB_CB(skb)->dccpd_reset_code =
789                                         DCCP_RESET_CODE_NO_CONNECTION;
790                 dccp_v6_ctl_send_reset(sk, skb);
791         }
792
793 discard_it:
794         kfree_skb(skb);
795         return 0;
796
797 discard_and_relse:
798         if (refcounted)
799                 sock_put(sk);
800         goto discard_it;
801 }
802
803 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
804                            int addr_len)
805 {
806         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
807         struct inet_connection_sock *icsk = inet_csk(sk);
808         struct inet_sock *inet = inet_sk(sk);
809         struct ipv6_pinfo *np = inet6_sk(sk);
810         struct dccp_sock *dp = dccp_sk(sk);
811         struct in6_addr *saddr = NULL, *final_p, final;
812         struct ipv6_txoptions *opt;
813         struct flowi6 fl6;
814         struct dst_entry *dst;
815         int addr_type;
816         int err;
817
818         dp->dccps_role = DCCP_ROLE_CLIENT;
819
820         if (addr_len < SIN6_LEN_RFC2133)
821                 return -EINVAL;
822
823         if (usin->sin6_family != AF_INET6)
824                 return -EAFNOSUPPORT;
825
826         memset(&fl6, 0, sizeof(fl6));
827
828         if (np->sndflow) {
829                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
830                 IP6_ECN_flow_init(fl6.flowlabel);
831                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
832                         struct ip6_flowlabel *flowlabel;
833                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
834                         if (flowlabel == NULL)
835                                 return -EINVAL;
836                         fl6_sock_release(flowlabel);
837                 }
838         }
839         /*
840          * connect() to INADDR_ANY means loopback (BSD'ism).
841          */
842         if (ipv6_addr_any(&usin->sin6_addr))
843                 usin->sin6_addr.s6_addr[15] = 1;
844
845         addr_type = ipv6_addr_type(&usin->sin6_addr);
846
847         if (addr_type & IPV6_ADDR_MULTICAST)
848                 return -ENETUNREACH;
849
850         if (addr_type & IPV6_ADDR_LINKLOCAL) {
851                 if (addr_len >= sizeof(struct sockaddr_in6) &&
852                     usin->sin6_scope_id) {
853                         /* If interface is set while binding, indices
854                          * must coincide.
855                          */
856                         if (sk->sk_bound_dev_if &&
857                             sk->sk_bound_dev_if != usin->sin6_scope_id)
858                                 return -EINVAL;
859
860                         sk->sk_bound_dev_if = usin->sin6_scope_id;
861                 }
862
863                 /* Connect to link-local address requires an interface */
864                 if (!sk->sk_bound_dev_if)
865                         return -EINVAL;
866         }
867
868         sk->sk_v6_daddr = usin->sin6_addr;
869         np->flow_label = fl6.flowlabel;
870
871         /*
872          * DCCP over IPv4
873          */
874         if (addr_type == IPV6_ADDR_MAPPED) {
875                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
876                 struct sockaddr_in sin;
877
878                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
879
880                 if (__ipv6_only_sock(sk))
881                         return -ENETUNREACH;
882
883                 sin.sin_family = AF_INET;
884                 sin.sin_port = usin->sin6_port;
885                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
886
887                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
888                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
889
890                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
891                 if (err) {
892                         icsk->icsk_ext_hdr_len = exthdrlen;
893                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
894                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
895                         goto failure;
896                 }
897                 np->saddr = sk->sk_v6_rcv_saddr;
898                 return err;
899         }
900
901         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
902                 saddr = &sk->sk_v6_rcv_saddr;
903
904         fl6.flowi6_proto = IPPROTO_DCCP;
905         fl6.daddr = sk->sk_v6_daddr;
906         fl6.saddr = saddr ? *saddr : np->saddr;
907         fl6.flowi6_oif = sk->sk_bound_dev_if;
908         fl6.fl6_dport = usin->sin6_port;
909         fl6.fl6_sport = inet->inet_sport;
910         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
911
912         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
913         final_p = fl6_update_dst(&fl6, opt, &final);
914
915         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
916         if (IS_ERR(dst)) {
917                 err = PTR_ERR(dst);
918                 goto failure;
919         }
920
921         if (saddr == NULL) {
922                 saddr = &fl6.saddr;
923                 sk->sk_v6_rcv_saddr = *saddr;
924         }
925
926         /* set the source address */
927         np->saddr = *saddr;
928         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
929
930         ip6_dst_store(sk, dst, NULL, NULL);
931
932         icsk->icsk_ext_hdr_len = 0;
933         if (opt)
934                 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
935
936         inet->inet_dport = usin->sin6_port;
937
938         dccp_set_state(sk, DCCP_REQUESTING);
939         err = inet6_hash_connect(&dccp_death_row, sk);
940         if (err)
941                 goto late_failure;
942
943         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
944                                                       sk->sk_v6_daddr.s6_addr32,
945                                                       inet->inet_sport,
946                                                       inet->inet_dport);
947         err = dccp_connect(sk);
948         if (err)
949                 goto late_failure;
950
951         return 0;
952
953 late_failure:
954         dccp_set_state(sk, DCCP_CLOSED);
955         __sk_dst_reset(sk);
956 failure:
957         inet->inet_dport = 0;
958         sk->sk_route_caps = 0;
959         return err;
960 }
961
962 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
963         .queue_xmit        = inet6_csk_xmit,
964         .send_check        = dccp_v6_send_check,
965         .rebuild_header    = inet6_sk_rebuild_header,
966         .conn_request      = dccp_v6_conn_request,
967         .syn_recv_sock     = dccp_v6_request_recv_sock,
968         .net_header_len    = sizeof(struct ipv6hdr),
969         .setsockopt        = ipv6_setsockopt,
970         .getsockopt        = ipv6_getsockopt,
971         .addr2sockaddr     = inet6_csk_addr2sockaddr,
972         .sockaddr_len      = sizeof(struct sockaddr_in6),
973 #ifdef CONFIG_COMPAT
974         .compat_setsockopt = compat_ipv6_setsockopt,
975         .compat_getsockopt = compat_ipv6_getsockopt,
976 #endif
977 };
978
979 /*
980  *      DCCP over IPv4 via INET6 API
981  */
982 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
983         .queue_xmit        = ip_queue_xmit,
984         .send_check        = dccp_v4_send_check,
985         .rebuild_header    = inet_sk_rebuild_header,
986         .conn_request      = dccp_v6_conn_request,
987         .syn_recv_sock     = dccp_v6_request_recv_sock,
988         .net_header_len    = sizeof(struct iphdr),
989         .setsockopt        = ipv6_setsockopt,
990         .getsockopt        = ipv6_getsockopt,
991         .addr2sockaddr     = inet6_csk_addr2sockaddr,
992         .sockaddr_len      = sizeof(struct sockaddr_in6),
993 #ifdef CONFIG_COMPAT
994         .compat_setsockopt = compat_ipv6_setsockopt,
995         .compat_getsockopt = compat_ipv6_getsockopt,
996 #endif
997 };
998
999 /* NOTE: A lot of things set to zero explicitly by call to
1000  *       sk_alloc() so need not be done here.
1001  */
1002 static int dccp_v6_init_sock(struct sock *sk)
1003 {
1004         static __u8 dccp_v6_ctl_sock_initialized;
1005         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
1006
1007         if (err == 0) {
1008                 if (unlikely(!dccp_v6_ctl_sock_initialized))
1009                         dccp_v6_ctl_sock_initialized = 1;
1010                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
1011         }
1012
1013         return err;
1014 }
1015
1016 static void dccp_v6_destroy_sock(struct sock *sk)
1017 {
1018         dccp_destroy_sock(sk);
1019         inet6_destroy_sock(sk);
1020 }
1021
1022 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
1023         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
1024 };
1025
1026 static struct proto dccp_v6_prot = {
1027         .name              = "DCCPv6",
1028         .owner             = THIS_MODULE,
1029         .close             = dccp_close,
1030         .connect           = dccp_v6_connect,
1031         .disconnect        = dccp_disconnect,
1032         .ioctl             = dccp_ioctl,
1033         .init              = dccp_v6_init_sock,
1034         .setsockopt        = dccp_setsockopt,
1035         .getsockopt        = dccp_getsockopt,
1036         .sendmsg           = dccp_sendmsg,
1037         .recvmsg           = dccp_recvmsg,
1038         .backlog_rcv       = dccp_v6_do_rcv,
1039         .hash              = inet6_hash,
1040         .unhash            = inet_unhash,
1041         .accept            = inet_csk_accept,
1042         .get_port          = inet_csk_get_port,
1043         .shutdown          = dccp_shutdown,
1044         .destroy           = dccp_v6_destroy_sock,
1045         .orphan_count      = &dccp_orphan_count,
1046         .max_header        = MAX_DCCP_HEADER,
1047         .obj_size          = sizeof(struct dccp6_sock),
1048         .slab_flags        = SLAB_TYPESAFE_BY_RCU,
1049         .rsk_prot          = &dccp6_request_sock_ops,
1050         .twsk_prot         = &dccp6_timewait_sock_ops,
1051         .h.hashinfo        = &dccp_hashinfo,
1052 #ifdef CONFIG_COMPAT
1053         .compat_setsockopt = compat_dccp_setsockopt,
1054         .compat_getsockopt = compat_dccp_getsockopt,
1055 #endif
1056 };
1057
1058 static const struct inet6_protocol dccp_v6_protocol = {
1059         .handler        = dccp_v6_rcv,
1060         .err_handler    = dccp_v6_err,
1061         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1062 };
1063
1064 static const struct proto_ops inet6_dccp_ops = {
1065         .family            = PF_INET6,
1066         .owner             = THIS_MODULE,
1067         .release           = inet6_release,
1068         .bind              = inet6_bind,
1069         .connect           = inet_stream_connect,
1070         .socketpair        = sock_no_socketpair,
1071         .accept            = inet_accept,
1072         .getname           = inet6_getname,
1073         .poll              = dccp_poll,
1074         .ioctl             = inet6_ioctl,
1075         .listen            = inet_dccp_listen,
1076         .shutdown          = inet_shutdown,
1077         .setsockopt        = sock_common_setsockopt,
1078         .getsockopt        = sock_common_getsockopt,
1079         .sendmsg           = inet_sendmsg,
1080         .recvmsg           = sock_common_recvmsg,
1081         .mmap              = sock_no_mmap,
1082         .sendpage          = sock_no_sendpage,
1083 #ifdef CONFIG_COMPAT
1084         .compat_setsockopt = compat_sock_common_setsockopt,
1085         .compat_getsockopt = compat_sock_common_getsockopt,
1086 #endif
1087 };
1088
1089 static struct inet_protosw dccp_v6_protosw = {
1090         .type           = SOCK_DCCP,
1091         .protocol       = IPPROTO_DCCP,
1092         .prot           = &dccp_v6_prot,
1093         .ops            = &inet6_dccp_ops,
1094         .flags          = INET_PROTOSW_ICSK,
1095 };
1096
1097 static int __net_init dccp_v6_init_net(struct net *net)
1098 {
1099         if (dccp_hashinfo.bhash == NULL)
1100                 return -ESOCKTNOSUPPORT;
1101
1102         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1103                                     SOCK_DCCP, IPPROTO_DCCP, net);
1104 }
1105
1106 static void __net_exit dccp_v6_exit_net(struct net *net)
1107 {
1108         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1109 }
1110
1111 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
1112 {
1113         inet_twsk_purge(&dccp_hashinfo, AF_INET6);
1114 }
1115
1116 static struct pernet_operations dccp_v6_ops = {
1117         .init   = dccp_v6_init_net,
1118         .exit   = dccp_v6_exit_net,
1119         .exit_batch = dccp_v6_exit_batch,
1120 };
1121
1122 static int __init dccp_v6_init(void)
1123 {
1124         int err = proto_register(&dccp_v6_prot, 1);
1125
1126         if (err)
1127                 goto out;
1128
1129         inet6_register_protosw(&dccp_v6_protosw);
1130
1131         err = register_pernet_subsys(&dccp_v6_ops);
1132         if (err)
1133                 goto out_destroy_ctl_sock;
1134
1135         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1136         if (err)
1137                 goto out_unregister_proto;
1138
1139 out:
1140         return err;
1141 out_unregister_proto:
1142         unregister_pernet_subsys(&dccp_v6_ops);
1143 out_destroy_ctl_sock:
1144         inet6_unregister_protosw(&dccp_v6_protosw);
1145         proto_unregister(&dccp_v6_prot);
1146         goto out;
1147 }
1148
1149 static void __exit dccp_v6_exit(void)
1150 {
1151         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1152         unregister_pernet_subsys(&dccp_v6_ops);
1153         inet6_unregister_protosw(&dccp_v6_protosw);
1154         proto_unregister(&dccp_v6_prot);
1155 }
1156
1157 module_init(dccp_v6_init);
1158 module_exit(dccp_v6_exit);
1159
1160 /*
1161  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1162  * values directly, Also cover the case where the protocol is not specified,
1163  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1164  */
1165 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1166 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1167 MODULE_LICENSE("GPL");
1168 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1169 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");