1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * DCCP over IPv6
4 * Linux INET6 implementation
5 *
6 * Based on net/dccp6/ipv6.c
7 *
8 * Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
9 */
10
11 #include <linux/module.h>
12 #include <linux/random.h>
13 #include <linux/slab.h>
14 #include <linux/xfrm.h>
15 #include <linux/string.h>
16
17 #include <net/addrconf.h>
18 #include <net/inet_common.h>
19 #include <net/inet_hashtables.h>
20 #include <net/inet_sock.h>
21 #include <net/inet6_connection_sock.h>
22 #include <net/inet6_hashtables.h>
23 #include <net/ip6_route.h>
24 #include <net/ipv6.h>
25 #include <net/protocol.h>
26 #include <net/transp_v6.h>
27 #include <net/ip6_checksum.h>
28 #include <net/xfrm.h>
29 #include <net/secure_seq.h>
30 #include <net/sock.h>
31
32 #include "dccp.h"
33 #include "ipv6.h"
34 #include "feat.h"
35
36 /* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */
37
38 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
39 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
40
41 /* add pseudo-header to DCCP checksum stored in skb->csum */
dccp_v6_csum_finish(struct sk_buff * skb,const struct in6_addr * saddr,const struct in6_addr * daddr)42 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
43 const struct in6_addr *saddr,
44 const struct in6_addr *daddr)
45 {
46 return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
47 }
48
dccp_v6_send_check(struct sock * sk,struct sk_buff * skb)49 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
50 {
51 struct ipv6_pinfo *np = inet6_sk(sk);
52 struct dccp_hdr *dh = dccp_hdr(skb);
53
54 dccp_csum_outgoing(skb);
55 dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
56 }
57
dccp_v6_init_sequence(struct sk_buff * skb)58 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
59 {
60 return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
61 ipv6_hdr(skb)->saddr.s6_addr32,
62 dccp_hdr(skb)->dccph_dport,
63 dccp_hdr(skb)->dccph_sport );
64
65 }
66
dccp_v6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)67 static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
68 u8 type, u8 code, int offset, __be32 info)
69 {
70 const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
71 const struct dccp_hdr *dh;
72 struct dccp_sock *dp;
73 struct ipv6_pinfo *np;
74 struct sock *sk;
75 int err;
76 __u64 seq;
77 struct net *net = dev_net(skb->dev);
78
79 /* Only need dccph_dport & dccph_sport which are the first
80 * 4 bytes in dccp header.
81 * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
82 */
83 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
84 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
85 dh = (struct dccp_hdr *)(skb->data + offset);
86
87 sk = __inet6_lookup_established(net, &dccp_hashinfo,
88 &hdr->daddr, dh->dccph_dport,
89 &hdr->saddr, ntohs(dh->dccph_sport),
90 inet6_iif(skb), 0);
91
92 if (!sk) {
93 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
94 ICMP6_MIB_INERRORS);
95 return -ENOENT;
96 }
97
98 if (sk->sk_state == DCCP_TIME_WAIT) {
99 inet_twsk_put(inet_twsk(sk));
100 return 0;
101 }
102 seq = dccp_hdr_seq(dh);
103 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
104 dccp_req_err(sk, seq);
105 return 0;
106 }
107
108 bh_lock_sock(sk);
109 if (sock_owned_by_user(sk))
110 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
111
112 if (sk->sk_state == DCCP_CLOSED)
113 goto out;
114
115 dp = dccp_sk(sk);
116 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
117 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
118 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
119 goto out;
120 }
121
122 np = inet6_sk(sk);
123
124 if (type == NDISC_REDIRECT) {
125 if (!sock_owned_by_user(sk)) {
126 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
127
128 if (dst)
129 dst->ops->redirect(dst, sk, skb);
130 }
131 goto out;
132 }
133
134 if (type == ICMPV6_PKT_TOOBIG) {
135 struct dst_entry *dst = NULL;
136
137 if (!ip6_sk_accept_pmtu(sk))
138 goto out;
139
140 if (sock_owned_by_user(sk))
141 goto out;
142 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
143 goto out;
144
145 dst = inet6_csk_update_pmtu(sk, ntohl(info));
146 if (!dst)
147 goto out;
148
149 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
150 dccp_sync_mss(sk, dst_mtu(dst));
151 goto out;
152 }
153
154 icmpv6_err_convert(type, code, &err);
155
156 /* Might be for an request_sock */
157 switch (sk->sk_state) {
158 case DCCP_REQUESTING:
159 case DCCP_RESPOND: /* Cannot happen.
160 It can, it SYNs are crossed. --ANK */
161 if (!sock_owned_by_user(sk)) {
162 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
163 sk->sk_err = err;
164 /*
165 * Wake people up to see the error
166 * (see connect in sock.c)
167 */
168 sk->sk_error_report(sk);
169 dccp_done(sk);
170 } else
171 sk->sk_err_soft = err;
172 goto out;
173 }
174
175 if (!sock_owned_by_user(sk) && np->recverr) {
176 sk->sk_err = err;
177 sk->sk_error_report(sk);
178 } else
179 sk->sk_err_soft = err;
180
181 out:
182 bh_unlock_sock(sk);
183 sock_put(sk);
184 return 0;
185 }
186
187
dccp_v6_send_response(const struct sock * sk,struct request_sock * req)188 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
189 {
190 struct inet_request_sock *ireq = inet_rsk(req);
191 struct ipv6_pinfo *np = inet6_sk(sk);
192 struct sk_buff *skb;
193 struct in6_addr *final_p, final;
194 struct flowi6 fl6;
195 int err = -1;
196 struct dst_entry *dst;
197
198 memset(&fl6, 0, sizeof(fl6));
199 fl6.flowi6_proto = IPPROTO_DCCP;
200 fl6.daddr = ireq->ir_v6_rmt_addr;
201 fl6.saddr = ireq->ir_v6_loc_addr;
202 fl6.flowlabel = 0;
203 fl6.flowi6_oif = ireq->ir_iif;
204 fl6.fl6_dport = ireq->ir_rmt_port;
205 fl6.fl6_sport = htons(ireq->ir_num);
206 security_req_classify_flow(req, flowi6_to_flowi_common(&fl6));
207
208
209 rcu_read_lock();
210 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
211 rcu_read_unlock();
212
213 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
214 if (IS_ERR(dst)) {
215 err = PTR_ERR(dst);
216 dst = NULL;
217 goto done;
218 }
219
220 skb = dccp_make_response(sk, dst, req);
221 if (skb != NULL) {
222 struct dccp_hdr *dh = dccp_hdr(skb);
223 struct ipv6_txoptions *opt;
224
225 dh->dccph_checksum = dccp_v6_csum_finish(skb,
226 &ireq->ir_v6_loc_addr,
227 &ireq->ir_v6_rmt_addr);
228 fl6.daddr = ireq->ir_v6_rmt_addr;
229 rcu_read_lock();
230 opt = ireq->ipv6_opt;
231 if (!opt)
232 opt = rcu_dereference(np->opt);
233 err = ip6_xmit(sk, skb, &fl6, sk->sk_mark, opt, np->tclass,
234 sk->sk_priority);
235 rcu_read_unlock();
236 err = net_xmit_eval(err);
237 }
238
239 done:
240 dst_release(dst);
241 return err;
242 }
243
dccp_v6_reqsk_destructor(struct request_sock * req)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
dccp_v6_ctl_send_reset(const struct sock * sk,struct sk_buff * rxskb)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_common(&fl6));
283
284 /* sk = NULL, but it is safe for now. RST socket required. */
285 dst = ip6_dst_lookup_flow(sock_net(ctl_sk), 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, 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
dccp_v6_conn_request(struct sock * sk,struct sk_buff * skb)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 (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
323 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
324 return 0;
325 }
326
327 if (dccp_bad_service_code(sk, service)) {
328 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
329 goto drop;
330 }
331 /*
332 * There are no SYN attacks on IPv6, yet...
333 */
334 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
335 if (inet_csk_reqsk_queue_is_full(sk))
336 goto drop;
337
338 if (sk_acceptq_is_full(sk))
339 goto drop;
340
341 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
342 if (req == NULL)
343 goto drop;
344
345 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
346 goto drop_and_free;
347
348 dreq = dccp_rsk(req);
349 if (dccp_parse_options(sk, dreq, skb))
350 goto drop_and_free;
351
352 if (security_inet_conn_request(sk, skb, req))
353 goto drop_and_free;
354
355 ireq = inet_rsk(req);
356 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
357 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
358 ireq->ireq_family = AF_INET6;
359 ireq->ir_mark = inet_request_mark(sk, skb);
360
361 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
362 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
363 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
364 refcount_inc(&skb->users);
365 ireq->pktopts = skb;
366 }
367 ireq->ir_iif = sk->sk_bound_dev_if;
368
369 /* So that link locals have meaning */
370 if (!sk->sk_bound_dev_if &&
371 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
372 ireq->ir_iif = inet6_iif(skb);
373
374 /*
375 * Step 3: Process LISTEN state
376 *
377 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
378 *
379 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
380 */
381 dreq->dreq_isr = dcb->dccpd_seq;
382 dreq->dreq_gsr = dreq->dreq_isr;
383 dreq->dreq_iss = dccp_v6_init_sequence(skb);
384 dreq->dreq_gss = dreq->dreq_iss;
385 dreq->dreq_service = service;
386
387 if (dccp_v6_send_response(sk, req))
388 goto drop_and_free;
389
390 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
391 reqsk_put(req);
392 return 0;
393
394 drop_and_free:
395 reqsk_free(req);
396 drop:
397 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
398 return -1;
399 }
400
dccp_v6_request_recv_sock(const struct sock * sk,struct sk_buff * skb,struct request_sock * req,struct dst_entry * dst,struct request_sock * req_unhash,bool * own_req)401 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
402 struct sk_buff *skb,
403 struct request_sock *req,
404 struct dst_entry *dst,
405 struct request_sock *req_unhash,
406 bool *own_req)
407 {
408 struct inet_request_sock *ireq = inet_rsk(req);
409 struct ipv6_pinfo *newnp;
410 const struct ipv6_pinfo *np = inet6_sk(sk);
411 struct ipv6_txoptions *opt;
412 struct inet_sock *newinet;
413 struct dccp6_sock *newdp6;
414 struct sock *newsk;
415
416 if (skb->protocol == htons(ETH_P_IP)) {
417 /*
418 * v6 mapped
419 */
420 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
421 req_unhash, own_req);
422 if (newsk == NULL)
423 return NULL;
424
425 newdp6 = (struct dccp6_sock *)newsk;
426 newinet = inet_sk(newsk);
427 newinet->pinet6 = &newdp6->inet6;
428 newnp = inet6_sk(newsk);
429
430 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
431
432 newnp->saddr = newsk->sk_v6_rcv_saddr;
433
434 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
435 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
436 newnp->pktoptions = NULL;
437 newnp->opt = NULL;
438 newnp->ipv6_mc_list = NULL;
439 newnp->ipv6_ac_list = NULL;
440 newnp->ipv6_fl_list = NULL;
441 newnp->mcast_oif = inet_iif(skb);
442 newnp->mcast_hops = ip_hdr(skb)->ttl;
443
444 /*
445 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
446 * here, dccp_create_openreq_child now does this for us, see the comment in
447 * that function for the gory details. -acme
448 */
449
450 /* It is tricky place. Until this moment IPv4 tcp
451 worked with IPv6 icsk.icsk_af_ops.
452 Sync it now.
453 */
454 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
455
456 return newsk;
457 }
458
459
460 if (sk_acceptq_is_full(sk))
461 goto out_overflow;
462
463 if (!dst) {
464 struct flowi6 fl6;
465
466 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
467 if (!dst)
468 goto out;
469 }
470
471 newsk = dccp_create_openreq_child(sk, req, skb);
472 if (newsk == NULL)
473 goto out_nonewsk;
474
475 /*
476 * No need to charge this sock to the relevant IPv6 refcnt debug socks
477 * count here, dccp_create_openreq_child now does this for us, see the
478 * comment in that function for the gory details. -acme
479 */
480
481 ip6_dst_store(newsk, dst, NULL, NULL);
482 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
483 NETIF_F_TSO);
484 newdp6 = (struct dccp6_sock *)newsk;
485 newinet = inet_sk(newsk);
486 newinet->pinet6 = &newdp6->inet6;
487 newnp = inet6_sk(newsk);
488
489 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
490
491 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
492 newnp->saddr = ireq->ir_v6_loc_addr;
493 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
494 newsk->sk_bound_dev_if = ireq->ir_iif;
495
496 /* Now IPv6 options...
497
498 First: no IPv4 options.
499 */
500 newinet->inet_opt = NULL;
501
502 /* Clone RX bits */
503 newnp->rxopt.all = np->rxopt.all;
504
505 newnp->ipv6_mc_list = NULL;
506 newnp->ipv6_ac_list = NULL;
507 newnp->ipv6_fl_list = NULL;
508 newnp->pktoptions = NULL;
509 newnp->opt = NULL;
510 newnp->mcast_oif = inet6_iif(skb);
511 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
512
513 /*
514 * Clone native IPv6 options from listening socket (if any)
515 *
516 * Yes, keeping reference count would be much more clever, but we make
517 * one more one thing there: reattach optmem to newsk.
518 */
519 opt = ireq->ipv6_opt;
520 if (!opt)
521 opt = rcu_dereference(np->opt);
522 if (opt) {
523 opt = ipv6_dup_options(newsk, opt);
524 RCU_INIT_POINTER(newnp->opt, opt);
525 }
526 inet_csk(newsk)->icsk_ext_hdr_len = 0;
527 if (opt)
528 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
529 opt->opt_flen;
530
531 dccp_sync_mss(newsk, dst_mtu(dst));
532
533 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
534 newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
535
536 if (__inet_inherit_port(sk, newsk) < 0) {
537 inet_csk_prepare_forced_close(newsk);
538 dccp_done(newsk);
539 goto out;
540 }
541 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL);
542 /* Clone pktoptions received with SYN, if we own the req */
543 if (*own_req && ireq->pktopts) {
544 newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk);
545 consume_skb(ireq->pktopts);
546 ireq->pktopts = NULL;
547 }
548
549 return newsk;
550
551 out_overflow:
552 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
553 out_nonewsk:
554 dst_release(dst);
555 out:
556 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
557 return NULL;
558 }
559
560 /* The socket must have it's spinlock held when we get
561 * here.
562 *
563 * We have a potential double-lock case here, so even when
564 * doing backlog processing we use the BH locking scheme.
565 * This is because we cannot sleep with the original spinlock
566 * held.
567 */
dccp_v6_do_rcv(struct sock * sk,struct sk_buff * skb)568 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
569 {
570 struct ipv6_pinfo *np = inet6_sk(sk);
571 struct sk_buff *opt_skb = NULL;
572
573 /* Imagine: socket is IPv6. IPv4 packet arrives,
574 goes to IPv4 receive handler and backlogged.
575 From backlog it always goes here. Kerboom...
576 Fortunately, dccp_rcv_established and rcv_established
577 handle them correctly, but it is not case with
578 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK
579 */
580
581 if (skb->protocol == htons(ETH_P_IP))
582 return dccp_v4_do_rcv(sk, skb);
583
584 if (sk_filter(sk, skb))
585 goto discard;
586
587 /*
588 * socket locking is here for SMP purposes as backlog rcv is currently
589 * called with bh processing disabled.
590 */
591
592 /* Do Stevens' IPV6_PKTOPTIONS.
593
594 Yes, guys, it is the only place in our code, where we
595 may make it not affecting IPv4.
596 The rest of code is protocol independent,
597 and I do not like idea to uglify IPv4.
598
599 Actually, all the idea behind IPV6_PKTOPTIONS
600 looks not very well thought. For now we latch
601 options, received in the last packet, enqueued
602 by tcp. Feel free to propose better solution.
603 --ANK (980728)
604 */
605 if (np->rxopt.all)
606 opt_skb = skb_clone_and_charge_r(skb, sk);
607
608 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
609 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
610 goto reset;
611 if (opt_skb)
612 goto ipv6_pktoptions;
613 return 0;
614 }
615
616 /*
617 * Step 3: Process LISTEN state
618 * If S.state == LISTEN,
619 * If P.type == Request or P contains a valid Init Cookie option,
620 * (* Must scan the packet's options to check for Init
621 * Cookies. Only Init Cookies are processed here,
622 * however; other options are processed in Step 8. This
623 * scan need only be performed if the endpoint uses Init
624 * Cookies *)
625 * (* Generate a new socket and switch to that socket *)
626 * Set S := new socket for this port pair
627 * S.state = RESPOND
628 * Choose S.ISS (initial seqno) or set from Init Cookies
629 * Initialize S.GAR := S.ISS
630 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
631 * Continue with S.state == RESPOND
632 * (* A Response packet will be generated in Step 11 *)
633 * Otherwise,
634 * Generate Reset(No Connection) unless P.type == Reset
635 * Drop packet and return
636 *
637 * NOTE: the check for the packet types is done in
638 * dccp_rcv_state_process
639 */
640
641 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
642 goto reset;
643 if (opt_skb)
644 goto ipv6_pktoptions;
645 return 0;
646
647 reset:
648 dccp_v6_ctl_send_reset(sk, skb);
649 discard:
650 if (opt_skb != NULL)
651 __kfree_skb(opt_skb);
652 kfree_skb(skb);
653 return 0;
654
655 /* Handling IPV6_PKTOPTIONS skb the similar
656 * way it's done for net/ipv6/tcp_ipv6.c
657 */
658 ipv6_pktoptions:
659 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) {
660 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
661 np->mcast_oif = inet6_iif(opt_skb);
662 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
663 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
664 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
665 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
666 if (np->repflow)
667 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
668 if (ipv6_opt_accepted(sk, opt_skb,
669 &DCCP_SKB_CB(opt_skb)->header.h6)) {
670 memmove(IP6CB(opt_skb),
671 &DCCP_SKB_CB(opt_skb)->header.h6,
672 sizeof(struct inet6_skb_parm));
673 opt_skb = xchg(&np->pktoptions, opt_skb);
674 } else {
675 __kfree_skb(opt_skb);
676 opt_skb = xchg(&np->pktoptions, NULL);
677 }
678 }
679
680 kfree_skb(opt_skb);
681 return 0;
682 }
683
dccp_v6_rcv(struct sk_buff * skb)684 static int dccp_v6_rcv(struct sk_buff *skb)
685 {
686 const struct dccp_hdr *dh;
687 bool refcounted;
688 struct sock *sk;
689 int min_cov;
690
691 /* Step 1: Check header basics */
692
693 if (dccp_invalid_packet(skb))
694 goto discard_it;
695
696 /* Step 1: If header checksum is incorrect, drop packet and return. */
697 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
698 &ipv6_hdr(skb)->daddr)) {
699 DCCP_WARN("dropped packet with invalid checksum\n");
700 goto discard_it;
701 }
702
703 dh = dccp_hdr(skb);
704
705 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
706 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
707
708 if (dccp_packet_without_ack(skb))
709 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
710 else
711 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
712
713 lookup:
714 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
715 dh->dccph_sport, dh->dccph_dport,
716 inet6_iif(skb), 0, &refcounted);
717 if (!sk) {
718 dccp_pr_debug("failed to look up flow ID in table and "
719 "get corresponding socket\n");
720 goto no_dccp_socket;
721 }
722
723 /*
724 * Step 2:
725 * ... or S.state == TIMEWAIT,
726 * Generate Reset(No Connection) unless P.type == Reset
727 * Drop packet and return
728 */
729 if (sk->sk_state == DCCP_TIME_WAIT) {
730 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
731 inet_twsk_put(inet_twsk(sk));
732 goto no_dccp_socket;
733 }
734
735 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
736 struct request_sock *req = inet_reqsk(sk);
737 struct sock *nsk;
738
739 sk = req->rsk_listener;
740 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
741 inet_csk_reqsk_queue_drop_and_put(sk, req);
742 goto lookup;
743 }
744 sock_hold(sk);
745 refcounted = true;
746 nsk = dccp_check_req(sk, skb, req);
747 if (!nsk) {
748 reqsk_put(req);
749 goto discard_and_relse;
750 }
751 if (nsk == sk) {
752 reqsk_put(req);
753 } else if (dccp_child_process(sk, nsk, skb)) {
754 dccp_v6_ctl_send_reset(sk, skb);
755 goto discard_and_relse;
756 } else {
757 sock_put(sk);
758 return 0;
759 }
760 }
761 /*
762 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
763 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
764 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
765 */
766 min_cov = dccp_sk(sk)->dccps_pcrlen;
767 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
768 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
769 dh->dccph_cscov, min_cov);
770 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
771 goto discard_and_relse;
772 }
773
774 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
775 goto discard_and_relse;
776
777 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4,
778 refcounted) ? -1 : 0;
779
780 no_dccp_socket:
781 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
782 goto discard_it;
783 /*
784 * Step 2:
785 * If no socket ...
786 * Generate Reset(No Connection) unless P.type == Reset
787 * Drop packet and return
788 */
789 if (dh->dccph_type != DCCP_PKT_RESET) {
790 DCCP_SKB_CB(skb)->dccpd_reset_code =
791 DCCP_RESET_CODE_NO_CONNECTION;
792 dccp_v6_ctl_send_reset(sk, skb);
793 }
794
795 discard_it:
796 kfree_skb(skb);
797 return 0;
798
799 discard_and_relse:
800 if (refcounted)
801 sock_put(sk);
802 goto discard_it;
803 }
804
dccp_v6_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)805 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
806 int addr_len)
807 {
808 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
809 struct inet_connection_sock *icsk = inet_csk(sk);
810 struct inet_sock *inet = inet_sk(sk);
811 struct ipv6_pinfo *np = inet6_sk(sk);
812 struct dccp_sock *dp = dccp_sk(sk);
813 struct in6_addr *saddr = NULL, *final_p, final;
814 struct ipv6_txoptions *opt;
815 struct flowi6 fl6;
816 struct dst_entry *dst;
817 int addr_type;
818 int err;
819
820 dp->dccps_role = DCCP_ROLE_CLIENT;
821
822 if (addr_len < SIN6_LEN_RFC2133)
823 return -EINVAL;
824
825 if (usin->sin6_family != AF_INET6)
826 return -EAFNOSUPPORT;
827
828 memset(&fl6, 0, sizeof(fl6));
829
830 if (np->sndflow) {
831 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
832 IP6_ECN_flow_init(fl6.flowlabel);
833 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
834 struct ip6_flowlabel *flowlabel;
835 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
836 if (IS_ERR(flowlabel))
837 return -EINVAL;
838 fl6_sock_release(flowlabel);
839 }
840 }
841 /*
842 * connect() to INADDR_ANY means loopback (BSD'ism).
843 */
844 if (ipv6_addr_any(&usin->sin6_addr))
845 usin->sin6_addr.s6_addr[15] = 1;
846
847 addr_type = ipv6_addr_type(&usin->sin6_addr);
848
849 if (addr_type & IPV6_ADDR_MULTICAST)
850 return -ENETUNREACH;
851
852 if (addr_type & IPV6_ADDR_LINKLOCAL) {
853 if (addr_len >= sizeof(struct sockaddr_in6) &&
854 usin->sin6_scope_id) {
855 /* If interface is set while binding, indices
856 * must coincide.
857 */
858 if (sk->sk_bound_dev_if &&
859 sk->sk_bound_dev_if != usin->sin6_scope_id)
860 return -EINVAL;
861
862 sk->sk_bound_dev_if = usin->sin6_scope_id;
863 }
864
865 /* Connect to link-local address requires an interface */
866 if (!sk->sk_bound_dev_if)
867 return -EINVAL;
868 }
869
870 sk->sk_v6_daddr = usin->sin6_addr;
871 np->flow_label = fl6.flowlabel;
872
873 /*
874 * DCCP over IPv4
875 */
876 if (addr_type == IPV6_ADDR_MAPPED) {
877 u32 exthdrlen = icsk->icsk_ext_hdr_len;
878 struct sockaddr_in sin;
879
880 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
881
882 if (__ipv6_only_sock(sk))
883 return -ENETUNREACH;
884
885 sin.sin_family = AF_INET;
886 sin.sin_port = usin->sin6_port;
887 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
888
889 icsk->icsk_af_ops = &dccp_ipv6_mapped;
890 sk->sk_backlog_rcv = dccp_v4_do_rcv;
891
892 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
893 if (err) {
894 icsk->icsk_ext_hdr_len = exthdrlen;
895 icsk->icsk_af_ops = &dccp_ipv6_af_ops;
896 sk->sk_backlog_rcv = dccp_v6_do_rcv;
897 goto failure;
898 }
899 np->saddr = sk->sk_v6_rcv_saddr;
900 return err;
901 }
902
903 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
904 saddr = &sk->sk_v6_rcv_saddr;
905
906 fl6.flowi6_proto = IPPROTO_DCCP;
907 fl6.daddr = sk->sk_v6_daddr;
908 fl6.saddr = saddr ? *saddr : np->saddr;
909 fl6.flowi6_oif = sk->sk_bound_dev_if;
910 fl6.fl6_dport = usin->sin6_port;
911 fl6.fl6_sport = inet->inet_sport;
912 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
913
914 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
915 final_p = fl6_update_dst(&fl6, opt, &final);
916
917 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
918 if (IS_ERR(dst)) {
919 err = PTR_ERR(dst);
920 goto failure;
921 }
922
923 if (saddr == NULL) {
924 saddr = &fl6.saddr;
925 sk->sk_v6_rcv_saddr = *saddr;
926 }
927
928 /* set the source address */
929 np->saddr = *saddr;
930 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
931
932 ip6_dst_store(sk, dst, NULL, NULL);
933
934 icsk->icsk_ext_hdr_len = 0;
935 if (opt)
936 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
937
938 inet->inet_dport = usin->sin6_port;
939
940 dccp_set_state(sk, DCCP_REQUESTING);
941 err = inet6_hash_connect(&dccp_death_row, sk);
942 if (err)
943 goto late_failure;
944
945 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
946 sk->sk_v6_daddr.s6_addr32,
947 inet->inet_sport,
948 inet->inet_dport);
949 err = dccp_connect(sk);
950 if (err)
951 goto late_failure;
952
953 return 0;
954
955 late_failure:
956 dccp_set_state(sk, DCCP_CLOSED);
957 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
958 inet_reset_saddr(sk);
959 __sk_dst_reset(sk);
960 failure:
961 inet->inet_dport = 0;
962 sk->sk_route_caps = 0;
963 return err;
964 }
965
966 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
967 .queue_xmit = inet6_csk_xmit,
968 .send_check = dccp_v6_send_check,
969 .rebuild_header = inet6_sk_rebuild_header,
970 .conn_request = dccp_v6_conn_request,
971 .syn_recv_sock = dccp_v6_request_recv_sock,
972 .net_header_len = sizeof(struct ipv6hdr),
973 .setsockopt = ipv6_setsockopt,
974 .getsockopt = ipv6_getsockopt,
975 .addr2sockaddr = inet6_csk_addr2sockaddr,
976 .sockaddr_len = sizeof(struct sockaddr_in6),
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 };
994
dccp_v6_sk_destruct(struct sock * sk)995 static void dccp_v6_sk_destruct(struct sock *sk)
996 {
997 dccp_destruct_common(sk);
998 inet6_sock_destruct(sk);
999 }
1000
1001 /* NOTE: A lot of things set to zero explicitly by call to
1002 * sk_alloc() so need not be done here.
1003 */
dccp_v6_init_sock(struct sock * sk)1004 static int dccp_v6_init_sock(struct sock *sk)
1005 {
1006 static __u8 dccp_v6_ctl_sock_initialized;
1007 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
1008
1009 if (err == 0) {
1010 if (unlikely(!dccp_v6_ctl_sock_initialized))
1011 dccp_v6_ctl_sock_initialized = 1;
1012 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
1013 sk->sk_destruct = dccp_v6_sk_destruct;
1014 }
1015
1016 return err;
1017 }
1018
1019 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
1020 .twsk_obj_size = sizeof(struct dccp6_timewait_sock),
1021 };
1022
1023 static struct proto dccp_v6_prot = {
1024 .name = "DCCPv6",
1025 .owner = THIS_MODULE,
1026 .close = dccp_close,
1027 .connect = dccp_v6_connect,
1028 .disconnect = dccp_disconnect,
1029 .ioctl = dccp_ioctl,
1030 .init = dccp_v6_init_sock,
1031 .setsockopt = dccp_setsockopt,
1032 .getsockopt = dccp_getsockopt,
1033 .sendmsg = dccp_sendmsg,
1034 .recvmsg = dccp_recvmsg,
1035 .backlog_rcv = dccp_v6_do_rcv,
1036 .hash = inet6_hash,
1037 .unhash = inet_unhash,
1038 .accept = inet_csk_accept,
1039 .get_port = inet_csk_get_port,
1040 .shutdown = dccp_shutdown,
1041 .destroy = dccp_destroy_sock,
1042 .orphan_count = &dccp_orphan_count,
1043 .max_header = MAX_DCCP_HEADER,
1044 .obj_size = sizeof(struct dccp6_sock),
1045 .slab_flags = SLAB_TYPESAFE_BY_RCU,
1046 .rsk_prot = &dccp6_request_sock_ops,
1047 .twsk_prot = &dccp6_timewait_sock_ops,
1048 .h.hashinfo = &dccp_hashinfo,
1049 };
1050
1051 static const struct inet6_protocol dccp_v6_protocol = {
1052 .handler = dccp_v6_rcv,
1053 .err_handler = dccp_v6_err,
1054 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1055 };
1056
1057 static const struct proto_ops inet6_dccp_ops = {
1058 .family = PF_INET6,
1059 .owner = THIS_MODULE,
1060 .release = inet6_release,
1061 .bind = inet6_bind,
1062 .connect = inet_stream_connect,
1063 .socketpair = sock_no_socketpair,
1064 .accept = inet_accept,
1065 .getname = inet6_getname,
1066 .poll = dccp_poll,
1067 .ioctl = inet6_ioctl,
1068 .gettstamp = sock_gettstamp,
1069 .listen = inet_dccp_listen,
1070 .shutdown = inet_shutdown,
1071 .setsockopt = sock_common_setsockopt,
1072 .getsockopt = sock_common_getsockopt,
1073 .sendmsg = inet_sendmsg,
1074 .recvmsg = sock_common_recvmsg,
1075 .mmap = sock_no_mmap,
1076 .sendpage = sock_no_sendpage,
1077 #ifdef CONFIG_COMPAT
1078 .compat_ioctl = inet6_compat_ioctl,
1079 #endif
1080 };
1081
1082 static struct inet_protosw dccp_v6_protosw = {
1083 .type = SOCK_DCCP,
1084 .protocol = IPPROTO_DCCP,
1085 .prot = &dccp_v6_prot,
1086 .ops = &inet6_dccp_ops,
1087 .flags = INET_PROTOSW_ICSK,
1088 };
1089
dccp_v6_init_net(struct net * net)1090 static int __net_init dccp_v6_init_net(struct net *net)
1091 {
1092 if (dccp_hashinfo.bhash == NULL)
1093 return -ESOCKTNOSUPPORT;
1094
1095 return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1096 SOCK_DCCP, IPPROTO_DCCP, net);
1097 }
1098
dccp_v6_exit_net(struct net * net)1099 static void __net_exit dccp_v6_exit_net(struct net *net)
1100 {
1101 inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1102 }
1103
dccp_v6_exit_batch(struct list_head * net_exit_list)1104 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
1105 {
1106 inet_twsk_purge(&dccp_hashinfo, AF_INET6);
1107 }
1108
1109 static struct pernet_operations dccp_v6_ops = {
1110 .init = dccp_v6_init_net,
1111 .exit = dccp_v6_exit_net,
1112 .exit_batch = dccp_v6_exit_batch,
1113 };
1114
dccp_v6_init(void)1115 static int __init dccp_v6_init(void)
1116 {
1117 int err = proto_register(&dccp_v6_prot, 1);
1118
1119 if (err)
1120 goto out;
1121
1122 inet6_register_protosw(&dccp_v6_protosw);
1123
1124 err = register_pernet_subsys(&dccp_v6_ops);
1125 if (err)
1126 goto out_destroy_ctl_sock;
1127
1128 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1129 if (err)
1130 goto out_unregister_proto;
1131
1132 out:
1133 return err;
1134 out_unregister_proto:
1135 unregister_pernet_subsys(&dccp_v6_ops);
1136 out_destroy_ctl_sock:
1137 inet6_unregister_protosw(&dccp_v6_protosw);
1138 proto_unregister(&dccp_v6_prot);
1139 goto out;
1140 }
1141
dccp_v6_exit(void)1142 static void __exit dccp_v6_exit(void)
1143 {
1144 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1145 unregister_pernet_subsys(&dccp_v6_ops);
1146 inet6_unregister_protosw(&dccp_v6_protosw);
1147 proto_unregister(&dccp_v6_prot);
1148 }
1149
1150 module_init(dccp_v6_init);
1151 module_exit(dccp_v6_exit);
1152
1153 /*
1154 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1155 * values directly, Also cover the case where the protocol is not specified,
1156 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1157 */
1158 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1159 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1160 MODULE_LICENSE("GPL");
1161 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1162 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");
1163