Merge remote-tracking branch 'grant/devicetree/merge' into dt-fixes
[firefly-linux-kernel-4.4.55.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 (sock_owned_by_user(sk))
145                         goto out;
146                 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
147                         goto out;
148
149                 dst = inet6_csk_update_pmtu(sk, ntohl(info));
150                 if (!dst)
151                         goto out;
152
153                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
154                         dccp_sync_mss(sk, dst_mtu(dst));
155                 goto out;
156         }
157
158         icmpv6_err_convert(type, code, &err);
159
160         /* Might be for an request_sock */
161         switch (sk->sk_state) {
162                 struct request_sock *req, **prev;
163         case DCCP_LISTEN:
164                 if (sock_owned_by_user(sk))
165                         goto out;
166
167                 req = inet6_csk_search_req(sk, &prev, dh->dccph_dport,
168                                            &hdr->daddr, &hdr->saddr,
169                                            inet6_iif(skb));
170                 if (req == NULL)
171                         goto out;
172
173                 /*
174                  * ICMPs are not backlogged, hence we cannot get an established
175                  * socket here.
176                  */
177                 WARN_ON(req->sk != NULL);
178
179                 if (!between48(seq, dccp_rsk(req)->dreq_iss,
180                                     dccp_rsk(req)->dreq_gss)) {
181                         NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
182                         goto out;
183                 }
184
185                 inet_csk_reqsk_queue_drop(sk, req, prev);
186                 goto out;
187
188         case DCCP_REQUESTING:
189         case DCCP_RESPOND:  /* Cannot happen.
190                                It can, it SYNs are crossed. --ANK */
191                 if (!sock_owned_by_user(sk)) {
192                         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
193                         sk->sk_err = err;
194                         /*
195                          * Wake people up to see the error
196                          * (see connect in sock.c)
197                          */
198                         sk->sk_error_report(sk);
199                         dccp_done(sk);
200                 } else
201                         sk->sk_err_soft = err;
202                 goto out;
203         }
204
205         if (!sock_owned_by_user(sk) && np->recverr) {
206                 sk->sk_err = err;
207                 sk->sk_error_report(sk);
208         } else
209                 sk->sk_err_soft = err;
210
211 out:
212         bh_unlock_sock(sk);
213         sock_put(sk);
214 }
215
216
217 static int dccp_v6_send_response(struct sock *sk, struct request_sock *req)
218 {
219         struct inet_request_sock *ireq = inet_rsk(req);
220         struct ipv6_pinfo *np = inet6_sk(sk);
221         struct sk_buff *skb;
222         struct in6_addr *final_p, final;
223         struct flowi6 fl6;
224         int err = -1;
225         struct dst_entry *dst;
226
227         memset(&fl6, 0, sizeof(fl6));
228         fl6.flowi6_proto = IPPROTO_DCCP;
229         fl6.daddr = ireq->ir_v6_rmt_addr;
230         fl6.saddr = ireq->ir_v6_loc_addr;
231         fl6.flowlabel = 0;
232         fl6.flowi6_oif = ireq->ir_iif;
233         fl6.fl6_dport = ireq->ir_rmt_port;
234         fl6.fl6_sport = htons(ireq->ir_num);
235         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
236
237
238         final_p = fl6_update_dst(&fl6, np->opt, &final);
239
240         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
241         if (IS_ERR(dst)) {
242                 err = PTR_ERR(dst);
243                 dst = NULL;
244                 goto done;
245         }
246
247         skb = dccp_make_response(sk, dst, req);
248         if (skb != NULL) {
249                 struct dccp_hdr *dh = dccp_hdr(skb);
250
251                 dh->dccph_checksum = dccp_v6_csum_finish(skb,
252                                                          &ireq->ir_v6_loc_addr,
253                                                          &ireq->ir_v6_rmt_addr);
254                 fl6.daddr = ireq->ir_v6_rmt_addr;
255                 err = ip6_xmit(sk, skb, &fl6, np->opt, np->tclass);
256                 err = net_xmit_eval(err);
257         }
258
259 done:
260         dst_release(dst);
261         return err;
262 }
263
264 static void dccp_v6_reqsk_destructor(struct request_sock *req)
265 {
266         dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
267         kfree_skb(inet_rsk(req)->pktopts);
268 }
269
270 static void dccp_v6_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
271 {
272         const struct ipv6hdr *rxip6h;
273         struct sk_buff *skb;
274         struct flowi6 fl6;
275         struct net *net = dev_net(skb_dst(rxskb)->dev);
276         struct sock *ctl_sk = net->dccp.v6_ctl_sk;
277         struct dst_entry *dst;
278
279         if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
280                 return;
281
282         if (!ipv6_unicast_destination(rxskb))
283                 return;
284
285         skb = dccp_ctl_make_reset(ctl_sk, rxskb);
286         if (skb == NULL)
287                 return;
288
289         rxip6h = ipv6_hdr(rxskb);
290         dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
291                                                             &rxip6h->daddr);
292
293         memset(&fl6, 0, sizeof(fl6));
294         fl6.daddr = rxip6h->saddr;
295         fl6.saddr = rxip6h->daddr;
296
297         fl6.flowi6_proto = IPPROTO_DCCP;
298         fl6.flowi6_oif = inet6_iif(rxskb);
299         fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
300         fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
301         security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
302
303         /* sk = NULL, but it is safe for now. RST socket required. */
304         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL, false);
305         if (!IS_ERR(dst)) {
306                 skb_dst_set(skb, dst);
307                 ip6_xmit(ctl_sk, skb, &fl6, NULL, 0);
308                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
309                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
310                 return;
311         }
312
313         kfree_skb(skb);
314 }
315
316 static struct request_sock_ops dccp6_request_sock_ops = {
317         .family         = AF_INET6,
318         .obj_size       = sizeof(struct dccp6_request_sock),
319         .rtx_syn_ack    = dccp_v6_send_response,
320         .send_ack       = dccp_reqsk_send_ack,
321         .destructor     = dccp_v6_reqsk_destructor,
322         .send_reset     = dccp_v6_ctl_send_reset,
323         .syn_ack_timeout = dccp_syn_ack_timeout,
324 };
325
326 static struct sock *dccp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
327 {
328         const struct dccp_hdr *dh = dccp_hdr(skb);
329         const struct ipv6hdr *iph = ipv6_hdr(skb);
330         struct sock *nsk;
331         struct request_sock **prev;
332         /* Find possible connection requests. */
333         struct request_sock *req = inet6_csk_search_req(sk, &prev,
334                                                         dh->dccph_sport,
335                                                         &iph->saddr,
336                                                         &iph->daddr,
337                                                         inet6_iif(skb));
338         if (req != NULL)
339                 return dccp_check_req(sk, skb, req, prev);
340
341         nsk = __inet6_lookup_established(sock_net(sk), &dccp_hashinfo,
342                                          &iph->saddr, dh->dccph_sport,
343                                          &iph->daddr, ntohs(dh->dccph_dport),
344                                          inet6_iif(skb));
345         if (nsk != NULL) {
346                 if (nsk->sk_state != DCCP_TIME_WAIT) {
347                         bh_lock_sock(nsk);
348                         return nsk;
349                 }
350                 inet_twsk_put(inet_twsk(nsk));
351                 return NULL;
352         }
353
354         return sk;
355 }
356
357 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
358 {
359         struct request_sock *req;
360         struct dccp_request_sock *dreq;
361         struct inet_request_sock *ireq;
362         struct ipv6_pinfo *np = inet6_sk(sk);
363         const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
364         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
365
366         if (skb->protocol == htons(ETH_P_IP))
367                 return dccp_v4_conn_request(sk, skb);
368
369         if (!ipv6_unicast_destination(skb))
370                 return 0;       /* discard, don't send a reset here */
371
372         if (dccp_bad_service_code(sk, service)) {
373                 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
374                 goto drop;
375         }
376         /*
377          * There are no SYN attacks on IPv6, yet...
378          */
379         dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
380         if (inet_csk_reqsk_queue_is_full(sk))
381                 goto drop;
382
383         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
384                 goto drop;
385
386         req = inet6_reqsk_alloc(&dccp6_request_sock_ops);
387         if (req == NULL)
388                 goto drop;
389
390         if (dccp_reqsk_init(req, dccp_sk(sk), skb))
391                 goto drop_and_free;
392
393         dreq = dccp_rsk(req);
394         if (dccp_parse_options(sk, dreq, skb))
395                 goto drop_and_free;
396
397         if (security_inet_conn_request(sk, skb, req))
398                 goto drop_and_free;
399
400         ireq = inet_rsk(req);
401         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
402         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
403
404         if (ipv6_opt_accepted(sk, skb) ||
405             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
406             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
407                 atomic_inc(&skb->users);
408                 ireq->pktopts = skb;
409         }
410         ireq->ir_iif = sk->sk_bound_dev_if;
411
412         /* So that link locals have meaning */
413         if (!sk->sk_bound_dev_if &&
414             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
415                 ireq->ir_iif = inet6_iif(skb);
416
417         /*
418          * Step 3: Process LISTEN state
419          *
420          *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
421          *
422          * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
423          */
424         dreq->dreq_isr     = dcb->dccpd_seq;
425         dreq->dreq_gsr     = dreq->dreq_isr;
426         dreq->dreq_iss     = dccp_v6_init_sequence(skb);
427         dreq->dreq_gss     = dreq->dreq_iss;
428         dreq->dreq_service = service;
429
430         if (dccp_v6_send_response(sk, req))
431                 goto drop_and_free;
432
433         inet6_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
434         return 0;
435
436 drop_and_free:
437         reqsk_free(req);
438 drop:
439         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
440         return -1;
441 }
442
443 static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
444                                               struct sk_buff *skb,
445                                               struct request_sock *req,
446                                               struct dst_entry *dst)
447 {
448         struct inet_request_sock *ireq = inet_rsk(req);
449         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
450         struct inet_sock *newinet;
451         struct dccp6_sock *newdp6;
452         struct sock *newsk;
453
454         if (skb->protocol == htons(ETH_P_IP)) {
455                 /*
456                  *      v6 mapped
457                  */
458                 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst);
459                 if (newsk == NULL)
460                         return NULL;
461
462                 newdp6 = (struct dccp6_sock *)newsk;
463                 newinet = inet_sk(newsk);
464                 newinet->pinet6 = &newdp6->inet6;
465                 newnp = inet6_sk(newsk);
466
467                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
468
469                 ipv6_addr_set_v4mapped(newinet->inet_daddr, &newsk->sk_v6_daddr);
470
471                 ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
472
473                 newsk->sk_v6_rcv_saddr = newnp->saddr;
474
475                 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
476                 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
477                 newnp->pktoptions  = NULL;
478                 newnp->opt         = NULL;
479                 newnp->mcast_oif   = inet6_iif(skb);
480                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
481
482                 /*
483                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
484                  * here, dccp_create_openreq_child now does this for us, see the comment in
485                  * that function for the gory details. -acme
486                  */
487
488                 /* It is tricky place. Until this moment IPv4 tcp
489                    worked with IPv6 icsk.icsk_af_ops.
490                    Sync it now.
491                  */
492                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
493
494                 return newsk;
495         }
496
497
498         if (sk_acceptq_is_full(sk))
499                 goto out_overflow;
500
501         if (dst == NULL) {
502                 struct in6_addr *final_p, final;
503                 struct flowi6 fl6;
504
505                 memset(&fl6, 0, sizeof(fl6));
506                 fl6.flowi6_proto = IPPROTO_DCCP;
507                 fl6.daddr = ireq->ir_v6_rmt_addr;
508                 final_p = fl6_update_dst(&fl6, np->opt, &final);
509                 fl6.saddr = ireq->ir_v6_loc_addr;
510                 fl6.flowi6_oif = sk->sk_bound_dev_if;
511                 fl6.fl6_dport = ireq->ir_rmt_port;
512                 fl6.fl6_sport = htons(ireq->ir_num);
513                 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
514
515                 dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
516                 if (IS_ERR(dst))
517                         goto out;
518         }
519
520         newsk = dccp_create_openreq_child(sk, req, skb);
521         if (newsk == NULL)
522                 goto out_nonewsk;
523
524         /*
525          * No need to charge this sock to the relevant IPv6 refcnt debug socks
526          * count here, dccp_create_openreq_child now does this for us, see the
527          * comment in that function for the gory details. -acme
528          */
529
530         __ip6_dst_store(newsk, dst, NULL, NULL);
531         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
532                                                       NETIF_F_TSO);
533         newdp6 = (struct dccp6_sock *)newsk;
534         newinet = inet_sk(newsk);
535         newinet->pinet6 = &newdp6->inet6;
536         newnp = inet6_sk(newsk);
537
538         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
539
540         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
541         newnp->saddr            = ireq->ir_v6_loc_addr;
542         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
543         newsk->sk_bound_dev_if  = ireq->ir_iif;
544
545         /* Now IPv6 options...
546
547            First: no IPv4 options.
548          */
549         newinet->inet_opt = NULL;
550
551         /* Clone RX bits */
552         newnp->rxopt.all = np->rxopt.all;
553
554         /* Clone pktoptions received with SYN */
555         newnp->pktoptions = NULL;
556         if (ireq->pktopts != NULL) {
557                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
558                 consume_skb(ireq->pktopts);
559                 ireq->pktopts = NULL;
560                 if (newnp->pktoptions)
561                         skb_set_owner_r(newnp->pktoptions, newsk);
562         }
563         newnp->opt        = NULL;
564         newnp->mcast_oif  = inet6_iif(skb);
565         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
566
567         /*
568          * Clone native IPv6 options from listening socket (if any)
569          *
570          * Yes, keeping reference count would be much more clever, but we make
571          * one more one thing there: reattach optmem to newsk.
572          */
573         if (np->opt != NULL)
574                 newnp->opt = ipv6_dup_options(newsk, np->opt);
575
576         inet_csk(newsk)->icsk_ext_hdr_len = 0;
577         if (newnp->opt != NULL)
578                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
579                                                      newnp->opt->opt_flen);
580
581         dccp_sync_mss(newsk, dst_mtu(dst));
582
583         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
584         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
585
586         if (__inet_inherit_port(sk, newsk) < 0) {
587                 inet_csk_prepare_forced_close(newsk);
588                 dccp_done(newsk);
589                 goto out;
590         }
591         __inet6_hash(newsk, NULL);
592
593         return newsk;
594
595 out_overflow:
596         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
597 out_nonewsk:
598         dst_release(dst);
599 out:
600         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
601         return NULL;
602 }
603
604 /* The socket must have it's spinlock held when we get
605  * here.
606  *
607  * We have a potential double-lock case here, so even when
608  * doing backlog processing we use the BH locking scheme.
609  * This is because we cannot sleep with the original spinlock
610  * held.
611  */
612 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
613 {
614         struct ipv6_pinfo *np = inet6_sk(sk);
615         struct sk_buff *opt_skb = NULL;
616
617         /* Imagine: socket is IPv6. IPv4 packet arrives,
618            goes to IPv4 receive handler and backlogged.
619            From backlog it always goes here. Kerboom...
620            Fortunately, dccp_rcv_established and rcv_established
621            handle them correctly, but it is not case with
622            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
623          */
624
625         if (skb->protocol == htons(ETH_P_IP))
626                 return dccp_v4_do_rcv(sk, skb);
627
628         if (sk_filter(sk, skb))
629                 goto discard;
630
631         /*
632          * socket locking is here for SMP purposes as backlog rcv is currently
633          * called with bh processing disabled.
634          */
635
636         /* Do Stevens' IPV6_PKTOPTIONS.
637
638            Yes, guys, it is the only place in our code, where we
639            may make it not affecting IPv4.
640            The rest of code is protocol independent,
641            and I do not like idea to uglify IPv4.
642
643            Actually, all the idea behind IPV6_PKTOPTIONS
644            looks not very well thought. For now we latch
645            options, received in the last packet, enqueued
646            by tcp. Feel free to propose better solution.
647                                                --ANK (980728)
648          */
649         if (np->rxopt.all)
650         /*
651          * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
652          *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
653          */
654                 opt_skb = skb_clone(skb, GFP_ATOMIC);
655
656         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
657                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
658                         goto reset;
659                 if (opt_skb) {
660                         /* XXX This is where we would goto ipv6_pktoptions. */
661                         __kfree_skb(opt_skb);
662                 }
663                 return 0;
664         }
665
666         /*
667          *  Step 3: Process LISTEN state
668          *     If S.state == LISTEN,
669          *       If P.type == Request or P contains a valid Init Cookie option,
670          *            (* Must scan the packet's options to check for Init
671          *               Cookies.  Only Init Cookies are processed here,
672          *               however; other options are processed in Step 8.  This
673          *               scan need only be performed if the endpoint uses Init
674          *               Cookies *)
675          *            (* Generate a new socket and switch to that socket *)
676          *            Set S := new socket for this port pair
677          *            S.state = RESPOND
678          *            Choose S.ISS (initial seqno) or set from Init Cookies
679          *            Initialize S.GAR := S.ISS
680          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
681          *            Continue with S.state == RESPOND
682          *            (* A Response packet will be generated in Step 11 *)
683          *       Otherwise,
684          *            Generate Reset(No Connection) unless P.type == Reset
685          *            Drop packet and return
686          *
687          * NOTE: the check for the packet types is done in
688          *       dccp_rcv_state_process
689          */
690         if (sk->sk_state == DCCP_LISTEN) {
691                 struct sock *nsk = dccp_v6_hnd_req(sk, skb);
692
693                 if (nsk == NULL)
694                         goto discard;
695                 /*
696                  * Queue it on the new socket if the new socket is active,
697                  * otherwise we just shortcircuit this and continue with
698                  * the new socket..
699                  */
700                 if (nsk != sk) {
701                         if (dccp_child_process(sk, nsk, skb))
702                                 goto reset;
703                         if (opt_skb != NULL)
704                                 __kfree_skb(opt_skb);
705                         return 0;
706                 }
707         }
708
709         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
710                 goto reset;
711         if (opt_skb) {
712                 /* XXX This is where we would goto ipv6_pktoptions. */
713                 __kfree_skb(opt_skb);
714         }
715         return 0;
716
717 reset:
718         dccp_v6_ctl_send_reset(sk, skb);
719 discard:
720         if (opt_skb != NULL)
721                 __kfree_skb(opt_skb);
722         kfree_skb(skb);
723         return 0;
724 }
725
726 static int dccp_v6_rcv(struct sk_buff *skb)
727 {
728         const struct dccp_hdr *dh;
729         struct sock *sk;
730         int min_cov;
731
732         /* Step 1: Check header basics */
733
734         if (dccp_invalid_packet(skb))
735                 goto discard_it;
736
737         /* Step 1: If header checksum is incorrect, drop packet and return. */
738         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
739                                      &ipv6_hdr(skb)->daddr)) {
740                 DCCP_WARN("dropped packet with invalid checksum\n");
741                 goto discard_it;
742         }
743
744         dh = dccp_hdr(skb);
745
746         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
747         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
748
749         if (dccp_packet_without_ack(skb))
750                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
751         else
752                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
753
754         /* Step 2:
755          *      Look up flow ID in table and get corresponding socket */
756         sk = __inet6_lookup_skb(&dccp_hashinfo, skb,
757                                 dh->dccph_sport, dh->dccph_dport);
758         /*
759          * Step 2:
760          *      If no socket ...
761          */
762         if (sk == NULL) {
763                 dccp_pr_debug("failed to look up flow ID in table and "
764                               "get corresponding socket\n");
765                 goto no_dccp_socket;
766         }
767
768         /*
769          * Step 2:
770          *      ... or S.state == TIMEWAIT,
771          *              Generate Reset(No Connection) unless P.type == Reset
772          *              Drop packet and return
773          */
774         if (sk->sk_state == DCCP_TIME_WAIT) {
775                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
776                 inet_twsk_put(inet_twsk(sk));
777                 goto no_dccp_socket;
778         }
779
780         /*
781          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
782          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
783          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
784          */
785         min_cov = dccp_sk(sk)->dccps_pcrlen;
786         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
787                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
788                               dh->dccph_cscov, min_cov);
789                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
790                 goto discard_and_relse;
791         }
792
793         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
794                 goto discard_and_relse;
795
796         return sk_receive_skb(sk, skb, 1) ? -1 : 0;
797
798 no_dccp_socket:
799         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
800                 goto discard_it;
801         /*
802          * Step 2:
803          *      If no socket ...
804          *              Generate Reset(No Connection) unless P.type == Reset
805          *              Drop packet and return
806          */
807         if (dh->dccph_type != DCCP_PKT_RESET) {
808                 DCCP_SKB_CB(skb)->dccpd_reset_code =
809                                         DCCP_RESET_CODE_NO_CONNECTION;
810                 dccp_v6_ctl_send_reset(sk, skb);
811         }
812
813 discard_it:
814         kfree_skb(skb);
815         return 0;
816
817 discard_and_relse:
818         sock_put(sk);
819         goto discard_it;
820 }
821
822 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
823                            int addr_len)
824 {
825         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
826         struct inet_connection_sock *icsk = inet_csk(sk);
827         struct inet_sock *inet = inet_sk(sk);
828         struct ipv6_pinfo *np = inet6_sk(sk);
829         struct dccp_sock *dp = dccp_sk(sk);
830         struct in6_addr *saddr = NULL, *final_p, final;
831         struct flowi6 fl6;
832         struct dst_entry *dst;
833         int addr_type;
834         int err;
835
836         dp->dccps_role = DCCP_ROLE_CLIENT;
837
838         if (addr_len < SIN6_LEN_RFC2133)
839                 return -EINVAL;
840
841         if (usin->sin6_family != AF_INET6)
842                 return -EAFNOSUPPORT;
843
844         memset(&fl6, 0, sizeof(fl6));
845
846         if (np->sndflow) {
847                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
848                 IP6_ECN_flow_init(fl6.flowlabel);
849                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
850                         struct ip6_flowlabel *flowlabel;
851                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
852                         if (flowlabel == NULL)
853                                 return -EINVAL;
854                         fl6_sock_release(flowlabel);
855                 }
856         }
857         /*
858          * connect() to INADDR_ANY means loopback (BSD'ism).
859          */
860         if (ipv6_addr_any(&usin->sin6_addr))
861                 usin->sin6_addr.s6_addr[15] = 1;
862
863         addr_type = ipv6_addr_type(&usin->sin6_addr);
864
865         if (addr_type & IPV6_ADDR_MULTICAST)
866                 return -ENETUNREACH;
867
868         if (addr_type & IPV6_ADDR_LINKLOCAL) {
869                 if (addr_len >= sizeof(struct sockaddr_in6) &&
870                     usin->sin6_scope_id) {
871                         /* If interface is set while binding, indices
872                          * must coincide.
873                          */
874                         if (sk->sk_bound_dev_if &&
875                             sk->sk_bound_dev_if != usin->sin6_scope_id)
876                                 return -EINVAL;
877
878                         sk->sk_bound_dev_if = usin->sin6_scope_id;
879                 }
880
881                 /* Connect to link-local address requires an interface */
882                 if (!sk->sk_bound_dev_if)
883                         return -EINVAL;
884         }
885
886         sk->sk_v6_daddr = usin->sin6_addr;
887         np->flow_label = fl6.flowlabel;
888
889         /*
890          * DCCP over IPv4
891          */
892         if (addr_type == IPV6_ADDR_MAPPED) {
893                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
894                 struct sockaddr_in sin;
895
896                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
897
898                 if (__ipv6_only_sock(sk))
899                         return -ENETUNREACH;
900
901                 sin.sin_family = AF_INET;
902                 sin.sin_port = usin->sin6_port;
903                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
904
905                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
906                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
907
908                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
909                 if (err) {
910                         icsk->icsk_ext_hdr_len = exthdrlen;
911                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
912                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
913                         goto failure;
914                 }
915                 ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
916                 ipv6_addr_set_v4mapped(inet->inet_rcv_saddr, &sk->sk_v6_rcv_saddr);
917
918                 return err;
919         }
920
921         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
922                 saddr = &sk->sk_v6_rcv_saddr;
923
924         fl6.flowi6_proto = IPPROTO_DCCP;
925         fl6.daddr = sk->sk_v6_daddr;
926         fl6.saddr = saddr ? *saddr : np->saddr;
927         fl6.flowi6_oif = sk->sk_bound_dev_if;
928         fl6.fl6_dport = usin->sin6_port;
929         fl6.fl6_sport = inet->inet_sport;
930         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
931
932         final_p = fl6_update_dst(&fl6, np->opt, &final);
933
934         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
935         if (IS_ERR(dst)) {
936                 err = PTR_ERR(dst);
937                 goto failure;
938         }
939
940         if (saddr == NULL) {
941                 saddr = &fl6.saddr;
942                 sk->sk_v6_rcv_saddr = *saddr;
943         }
944
945         /* set the source address */
946         np->saddr = *saddr;
947         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
948
949         __ip6_dst_store(sk, dst, NULL, NULL);
950
951         icsk->icsk_ext_hdr_len = 0;
952         if (np->opt != NULL)
953                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
954                                           np->opt->opt_nflen);
955
956         inet->inet_dport = usin->sin6_port;
957
958         dccp_set_state(sk, DCCP_REQUESTING);
959         err = inet6_hash_connect(&dccp_death_row, sk);
960         if (err)
961                 goto late_failure;
962
963         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
964                                                       sk->sk_v6_daddr.s6_addr32,
965                                                       inet->inet_sport,
966                                                       inet->inet_dport);
967         err = dccp_connect(sk);
968         if (err)
969                 goto late_failure;
970
971         return 0;
972
973 late_failure:
974         dccp_set_state(sk, DCCP_CLOSED);
975         __sk_dst_reset(sk);
976 failure:
977         inet->inet_dport = 0;
978         sk->sk_route_caps = 0;
979         return err;
980 }
981
982 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
983         .queue_xmit        = inet6_csk_xmit,
984         .send_check        = dccp_v6_send_check,
985         .rebuild_header    = inet6_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 ipv6hdr),
989         .setsockopt        = ipv6_setsockopt,
990         .getsockopt        = ipv6_getsockopt,
991         .addr2sockaddr     = inet6_csk_addr2sockaddr,
992         .sockaddr_len      = sizeof(struct sockaddr_in6),
993         .bind_conflict     = inet6_csk_bind_conflict,
994 #ifdef CONFIG_COMPAT
995         .compat_setsockopt = compat_ipv6_setsockopt,
996         .compat_getsockopt = compat_ipv6_getsockopt,
997 #endif
998 };
999
1000 /*
1001  *      DCCP over IPv4 via INET6 API
1002  */
1003 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
1004         .queue_xmit        = ip_queue_xmit,
1005         .send_check        = dccp_v4_send_check,
1006         .rebuild_header    = inet_sk_rebuild_header,
1007         .conn_request      = dccp_v6_conn_request,
1008         .syn_recv_sock     = dccp_v6_request_recv_sock,
1009         .net_header_len    = sizeof(struct iphdr),
1010         .setsockopt        = ipv6_setsockopt,
1011         .getsockopt        = ipv6_getsockopt,
1012         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1013         .sockaddr_len      = sizeof(struct sockaddr_in6),
1014 #ifdef CONFIG_COMPAT
1015         .compat_setsockopt = compat_ipv6_setsockopt,
1016         .compat_getsockopt = compat_ipv6_getsockopt,
1017 #endif
1018 };
1019
1020 /* NOTE: A lot of things set to zero explicitly by call to
1021  *       sk_alloc() so need not be done here.
1022  */
1023 static int dccp_v6_init_sock(struct sock *sk)
1024 {
1025         static __u8 dccp_v6_ctl_sock_initialized;
1026         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
1027
1028         if (err == 0) {
1029                 if (unlikely(!dccp_v6_ctl_sock_initialized))
1030                         dccp_v6_ctl_sock_initialized = 1;
1031                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
1032         }
1033
1034         return err;
1035 }
1036
1037 static void dccp_v6_destroy_sock(struct sock *sk)
1038 {
1039         dccp_destroy_sock(sk);
1040         inet6_destroy_sock(sk);
1041 }
1042
1043 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
1044         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
1045 };
1046
1047 static struct proto dccp_v6_prot = {
1048         .name              = "DCCPv6",
1049         .owner             = THIS_MODULE,
1050         .close             = dccp_close,
1051         .connect           = dccp_v6_connect,
1052         .disconnect        = dccp_disconnect,
1053         .ioctl             = dccp_ioctl,
1054         .init              = dccp_v6_init_sock,
1055         .setsockopt        = dccp_setsockopt,
1056         .getsockopt        = dccp_getsockopt,
1057         .sendmsg           = dccp_sendmsg,
1058         .recvmsg           = dccp_recvmsg,
1059         .backlog_rcv       = dccp_v6_do_rcv,
1060         .hash              = dccp_v6_hash,
1061         .unhash            = inet_unhash,
1062         .accept            = inet_csk_accept,
1063         .get_port          = inet_csk_get_port,
1064         .shutdown          = dccp_shutdown,
1065         .destroy           = dccp_v6_destroy_sock,
1066         .orphan_count      = &dccp_orphan_count,
1067         .max_header        = MAX_DCCP_HEADER,
1068         .obj_size          = sizeof(struct dccp6_sock),
1069         .slab_flags        = SLAB_DESTROY_BY_RCU,
1070         .rsk_prot          = &dccp6_request_sock_ops,
1071         .twsk_prot         = &dccp6_timewait_sock_ops,
1072         .h.hashinfo        = &dccp_hashinfo,
1073 #ifdef CONFIG_COMPAT
1074         .compat_setsockopt = compat_dccp_setsockopt,
1075         .compat_getsockopt = compat_dccp_getsockopt,
1076 #endif
1077 };
1078
1079 static const struct inet6_protocol dccp_v6_protocol = {
1080         .handler        = dccp_v6_rcv,
1081         .err_handler    = dccp_v6_err,
1082         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1083 };
1084
1085 static const struct proto_ops inet6_dccp_ops = {
1086         .family            = PF_INET6,
1087         .owner             = THIS_MODULE,
1088         .release           = inet6_release,
1089         .bind              = inet6_bind,
1090         .connect           = inet_stream_connect,
1091         .socketpair        = sock_no_socketpair,
1092         .accept            = inet_accept,
1093         .getname           = inet6_getname,
1094         .poll              = dccp_poll,
1095         .ioctl             = inet6_ioctl,
1096         .listen            = inet_dccp_listen,
1097         .shutdown          = inet_shutdown,
1098         .setsockopt        = sock_common_setsockopt,
1099         .getsockopt        = sock_common_getsockopt,
1100         .sendmsg           = inet_sendmsg,
1101         .recvmsg           = sock_common_recvmsg,
1102         .mmap              = sock_no_mmap,
1103         .sendpage          = sock_no_sendpage,
1104 #ifdef CONFIG_COMPAT
1105         .compat_setsockopt = compat_sock_common_setsockopt,
1106         .compat_getsockopt = compat_sock_common_getsockopt,
1107 #endif
1108 };
1109
1110 static struct inet_protosw dccp_v6_protosw = {
1111         .type           = SOCK_DCCP,
1112         .protocol       = IPPROTO_DCCP,
1113         .prot           = &dccp_v6_prot,
1114         .ops            = &inet6_dccp_ops,
1115         .flags          = INET_PROTOSW_ICSK,
1116 };
1117
1118 static int __net_init dccp_v6_init_net(struct net *net)
1119 {
1120         if (dccp_hashinfo.bhash == NULL)
1121                 return -ESOCKTNOSUPPORT;
1122
1123         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1124                                     SOCK_DCCP, IPPROTO_DCCP, net);
1125 }
1126
1127 static void __net_exit dccp_v6_exit_net(struct net *net)
1128 {
1129         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1130 }
1131
1132 static struct pernet_operations dccp_v6_ops = {
1133         .init   = dccp_v6_init_net,
1134         .exit   = dccp_v6_exit_net,
1135 };
1136
1137 static int __init dccp_v6_init(void)
1138 {
1139         int err = proto_register(&dccp_v6_prot, 1);
1140
1141         if (err != 0)
1142                 goto out;
1143
1144         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1145         if (err != 0)
1146                 goto out_unregister_proto;
1147
1148         inet6_register_protosw(&dccp_v6_protosw);
1149
1150         err = register_pernet_subsys(&dccp_v6_ops);
1151         if (err != 0)
1152                 goto out_destroy_ctl_sock;
1153 out:
1154         return err;
1155
1156 out_destroy_ctl_sock:
1157         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1158         inet6_unregister_protosw(&dccp_v6_protosw);
1159 out_unregister_proto:
1160         proto_unregister(&dccp_v6_prot);
1161         goto out;
1162 }
1163
1164 static void __exit dccp_v6_exit(void)
1165 {
1166         unregister_pernet_subsys(&dccp_v6_ops);
1167         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1168         inet6_unregister_protosw(&dccp_v6_protosw);
1169         proto_unregister(&dccp_v6_prot);
1170 }
1171
1172 module_init(dccp_v6_init);
1173 module_exit(dccp_v6_exit);
1174
1175 /*
1176  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1177  * values directly, Also cover the case where the protocol is not specified,
1178  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1179  */
1180 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1181 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1182 MODULE_LICENSE("GPL");
1183 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1184 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");