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/netns/generic.h>
31 #include <net/sock.h>
32 #include <net/rstreason.h>
33
34 #include "dccp.h"
35 #include "ipv6.h"
36 #include "feat.h"
37
38 struct dccp_v6_pernet {
39 struct sock *v6_ctl_sk;
40 };
41
42 static unsigned int dccp_v6_pernet_id __read_mostly;
43
44 /* The per-net v6_ctl_sk is used for sending RSTs and ACKs */
45
46 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
47 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
48
49 /* 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)50 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
51 const struct in6_addr *saddr,
52 const struct in6_addr *daddr)
53 {
54 return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
55 }
56
dccp_v6_send_check(struct sock * sk,struct sk_buff * skb)57 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
58 {
59 struct ipv6_pinfo *np = inet6_sk(sk);
60 struct dccp_hdr *dh = dccp_hdr(skb);
61
62 dccp_csum_outgoing(skb);
63 dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
64 }
65
dccp_v6_init_sequence(struct sk_buff * skb)66 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
67 {
68 return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
69 ipv6_hdr(skb)->saddr.s6_addr32,
70 dccp_hdr(skb)->dccph_dport,
71 dccp_hdr(skb)->dccph_sport );
72
73 }
74
dccp_v6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)75 static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
76 u8 type, u8 code, int offset, __be32 info)
77 {
78 const struct ipv6hdr *hdr;
79 const struct dccp_hdr *dh;
80 struct dccp_sock *dp;
81 struct ipv6_pinfo *np;
82 struct sock *sk;
83 int err;
84 __u64 seq;
85 struct net *net = dev_net(skb->dev);
86
87 if (!pskb_may_pull(skb, offset + sizeof(*dh)))
88 return -EINVAL;
89 dh = (struct dccp_hdr *)(skb->data + offset);
90 if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh)))
91 return -EINVAL;
92 hdr = (const struct ipv6hdr *)skb->data;
93 dh = (struct dccp_hdr *)(skb->data + offset);
94
95 sk = __inet6_lookup_established(net, &dccp_hashinfo,
96 &hdr->daddr, dh->dccph_dport,
97 &hdr->saddr, ntohs(dh->dccph_sport),
98 inet6_iif(skb), 0);
99
100 if (!sk) {
101 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
102 ICMP6_MIB_INERRORS);
103 return -ENOENT;
104 }
105
106 if (sk->sk_state == DCCP_TIME_WAIT) {
107 inet_twsk_put(inet_twsk(sk));
108 return 0;
109 }
110 seq = dccp_hdr_seq(dh);
111 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
112 dccp_req_err(sk, seq);
113 return 0;
114 }
115
116 bh_lock_sock(sk);
117 if (sock_owned_by_user(sk))
118 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
119
120 if (sk->sk_state == DCCP_CLOSED)
121 goto out;
122
123 dp = dccp_sk(sk);
124 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
125 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
126 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
127 goto out;
128 }
129
130 np = inet6_sk(sk);
131
132 if (type == NDISC_REDIRECT) {
133 if (!sock_owned_by_user(sk)) {
134 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
135
136 if (dst)
137 dst->ops->redirect(dst, sk, skb);
138 }
139 goto out;
140 }
141
142 if (type == ICMPV6_PKT_TOOBIG) {
143 struct dst_entry *dst = NULL;
144
145 if (!ip6_sk_accept_pmtu(sk))
146 goto out;
147
148 if (sock_owned_by_user(sk))
149 goto out;
150 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
151 goto out;
152
153 dst = inet6_csk_update_pmtu(sk, ntohl(info));
154 if (!dst)
155 goto out;
156
157 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
158 dccp_sync_mss(sk, dst_mtu(dst));
159 goto out;
160 }
161
162 icmpv6_err_convert(type, code, &err);
163
164 /* Might be for an request_sock */
165 switch (sk->sk_state) {
166 case DCCP_REQUESTING:
167 case DCCP_RESPOND: /* Cannot happen.
168 It can, it SYNs are crossed. --ANK */
169 if (!sock_owned_by_user(sk)) {
170 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
171 sk->sk_err = err;
172 /*
173 * Wake people up to see the error
174 * (see connect in sock.c)
175 */
176 sk_error_report(sk);
177 dccp_done(sk);
178 } else {
179 WRITE_ONCE(sk->sk_err_soft, err);
180 }
181 goto out;
182 }
183
184 if (!sock_owned_by_user(sk) && inet6_test_bit(RECVERR6, sk)) {
185 sk->sk_err = err;
186 sk_error_report(sk);
187 } else {
188 WRITE_ONCE(sk->sk_err_soft, err);
189 }
190 out:
191 bh_unlock_sock(sk);
192 sock_put(sk);
193 return 0;
194 }
195
196
dccp_v6_send_response(const struct sock * sk,struct request_sock * req)197 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
198 {
199 struct inet_request_sock *ireq = inet_rsk(req);
200 struct ipv6_pinfo *np = inet6_sk(sk);
201 struct sk_buff *skb;
202 struct in6_addr *final_p, final;
203 struct flowi6 fl6;
204 int err = -1;
205 struct dst_entry *dst;
206
207 memset(&fl6, 0, sizeof(fl6));
208 fl6.flowi6_proto = IPPROTO_DCCP;
209 fl6.daddr = ireq->ir_v6_rmt_addr;
210 fl6.saddr = ireq->ir_v6_loc_addr;
211 fl6.flowlabel = 0;
212 fl6.flowi6_oif = ireq->ir_iif;
213 fl6.fl6_dport = ireq->ir_rmt_port;
214 fl6.fl6_sport = htons(ireq->ir_num);
215 security_req_classify_flow(req, flowi6_to_flowi_common(&fl6));
216
217
218 rcu_read_lock();
219 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
220 rcu_read_unlock();
221
222 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
223 if (IS_ERR(dst)) {
224 err = PTR_ERR(dst);
225 dst = NULL;
226 goto done;
227 }
228
229 skb = dccp_make_response(sk, dst, req);
230 if (skb != NULL) {
231 struct dccp_hdr *dh = dccp_hdr(skb);
232 struct ipv6_txoptions *opt;
233
234 dh->dccph_checksum = dccp_v6_csum_finish(skb,
235 &ireq->ir_v6_loc_addr,
236 &ireq->ir_v6_rmt_addr);
237 fl6.daddr = ireq->ir_v6_rmt_addr;
238 rcu_read_lock();
239 opt = ireq->ipv6_opt;
240 if (!opt)
241 opt = rcu_dereference(np->opt);
242 err = ip6_xmit(sk, skb, &fl6, READ_ONCE(sk->sk_mark), opt,
243 np->tclass, READ_ONCE(sk->sk_priority));
244 rcu_read_unlock();
245 err = net_xmit_eval(err);
246 }
247
248 done:
249 dst_release(dst);
250 return err;
251 }
252
dccp_v6_reqsk_destructor(struct request_sock * req)253 static void dccp_v6_reqsk_destructor(struct request_sock *req)
254 {
255 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
256 kfree(inet_rsk(req)->ipv6_opt);
257 kfree_skb(inet_rsk(req)->pktopts);
258 }
259
dccp_v6_ctl_send_reset(const struct sock * sk,struct sk_buff * rxskb,enum sk_rst_reason reason)260 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb,
261 enum sk_rst_reason reason)
262 {
263 const struct ipv6hdr *rxip6h;
264 struct sk_buff *skb;
265 struct flowi6 fl6;
266 struct net *net = dev_net(skb_dst(rxskb)->dev);
267 struct dccp_v6_pernet *pn;
268 struct sock *ctl_sk;
269 struct dst_entry *dst;
270
271 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
272 return;
273
274 if (!ipv6_unicast_destination(rxskb))
275 return;
276
277 pn = net_generic(net, dccp_v6_pernet_id);
278 ctl_sk = pn->v6_ctl_sk;
279 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
280 if (skb == NULL)
281 return;
282
283 rxip6h = ipv6_hdr(rxskb);
284 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
285 &rxip6h->daddr);
286
287 memset(&fl6, 0, sizeof(fl6));
288 fl6.daddr = rxip6h->saddr;
289 fl6.saddr = rxip6h->daddr;
290
291 fl6.flowi6_proto = IPPROTO_DCCP;
292 fl6.flowi6_oif = inet6_iif(rxskb);
293 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
294 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
295 security_skb_classify_flow(rxskb, flowi6_to_flowi_common(&fl6));
296
297 /* sk = NULL, but it is safe for now. RST socket required. */
298 dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL);
299 if (!IS_ERR(dst)) {
300 skb_dst_set(skb, dst);
301 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0, 0);
302 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
303 DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
304 return;
305 }
306
307 kfree_skb(skb);
308 }
309
310 static struct request_sock_ops dccp6_request_sock_ops = {
311 .family = AF_INET6,
312 .obj_size = sizeof(struct dccp6_request_sock),
313 .rtx_syn_ack = dccp_v6_send_response,
314 .send_ack = dccp_reqsk_send_ack,
315 .destructor = dccp_v6_reqsk_destructor,
316 .send_reset = dccp_v6_ctl_send_reset,
317 .syn_ack_timeout = dccp_syn_ack_timeout,
318 };
319
dccp_v6_conn_request(struct sock * sk,struct sk_buff * skb)320 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
321 {
322 struct request_sock *req;
323 struct dccp_request_sock *dreq;
324 struct inet_request_sock *ireq;
325 struct ipv6_pinfo *np = inet6_sk(sk);
326 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
327 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
328
329 if (skb->protocol == htons(ETH_P_IP))
330 return dccp_v4_conn_request(sk, skb);
331
332 if (!ipv6_unicast_destination(skb))
333 return 0; /* discard, don't send a reset here */
334
335 if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
336 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
337 return 0;
338 }
339
340 if (dccp_bad_service_code(sk, service)) {
341 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
342 goto drop;
343 }
344 /*
345 * There are no SYN attacks on IPv6, yet...
346 */
347 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
348 if (inet_csk_reqsk_queue_is_full(sk))
349 goto drop;
350
351 if (sk_acceptq_is_full(sk))
352 goto drop;
353
354 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
355 if (req == NULL)
356 goto drop;
357
358 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
359 goto drop_and_free;
360
361 dreq = dccp_rsk(req);
362 if (dccp_parse_options(sk, dreq, skb))
363 goto drop_and_free;
364
365 ireq = inet_rsk(req);
366 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
367 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
368 ireq->ir_rmt_addr = LOOPBACK4_IPV6;
369 ireq->ir_loc_addr = LOOPBACK4_IPV6;
370
371 ireq->ireq_family = AF_INET6;
372 ireq->ir_mark = inet_request_mark(sk, skb);
373
374 if (security_inet_conn_request(sk, skb, req))
375 goto drop_and_free;
376
377 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
378 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
379 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
380 refcount_inc(&skb->users);
381 ireq->pktopts = skb;
382 }
383 ireq->ir_iif = READ_ONCE(sk->sk_bound_dev_if);
384
385 /* So that link locals have meaning */
386 if (!ireq->ir_iif &&
387 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
388 ireq->ir_iif = inet6_iif(skb);
389
390 /*
391 * Step 3: Process LISTEN state
392 *
393 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
394 *
395 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
396 */
397 dreq->dreq_isr = dcb->dccpd_seq;
398 dreq->dreq_gsr = dreq->dreq_isr;
399 dreq->dreq_iss = dccp_v6_init_sequence(skb);
400 dreq->dreq_gss = dreq->dreq_iss;
401 dreq->dreq_service = service;
402
403 if (dccp_v6_send_response(sk, req))
404 goto drop_and_free;
405
406 if (unlikely(!inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT)))
407 reqsk_free(req);
408 else
409 reqsk_put(req);
410
411 return 0;
412
413 drop_and_free:
414 reqsk_free(req);
415 drop:
416 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
417 return -1;
418 }
419
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)420 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
421 struct sk_buff *skb,
422 struct request_sock *req,
423 struct dst_entry *dst,
424 struct request_sock *req_unhash,
425 bool *own_req)
426 {
427 struct inet_request_sock *ireq = inet_rsk(req);
428 struct ipv6_pinfo *newnp;
429 const struct ipv6_pinfo *np = inet6_sk(sk);
430 struct ipv6_txoptions *opt;
431 struct inet_sock *newinet;
432 struct dccp6_sock *newdp6;
433 struct sock *newsk;
434
435 if (skb->protocol == htons(ETH_P_IP)) {
436 /*
437 * v6 mapped
438 */
439 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
440 req_unhash, own_req);
441 if (newsk == NULL)
442 return NULL;
443
444 newdp6 = (struct dccp6_sock *)newsk;
445 newinet = inet_sk(newsk);
446 newinet->pinet6 = &newdp6->inet6;
447 newnp = inet6_sk(newsk);
448
449 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
450
451 newnp->saddr = newsk->sk_v6_rcv_saddr;
452
453 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
454 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
455 newnp->pktoptions = NULL;
456 newnp->opt = NULL;
457 newnp->ipv6_mc_list = NULL;
458 newnp->ipv6_ac_list = NULL;
459 newnp->ipv6_fl_list = NULL;
460 newnp->mcast_oif = inet_iif(skb);
461 newnp->mcast_hops = ip_hdr(skb)->ttl;
462
463 /*
464 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
465 * here, dccp_create_openreq_child now does this for us, see the comment in
466 * that function for the gory details. -acme
467 */
468
469 /* It is tricky place. Until this moment IPv4 tcp
470 worked with IPv6 icsk.icsk_af_ops.
471 Sync it now.
472 */
473 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
474
475 return newsk;
476 }
477
478
479 if (sk_acceptq_is_full(sk))
480 goto out_overflow;
481
482 if (!dst) {
483 struct flowi6 fl6;
484
485 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
486 if (!dst)
487 goto out;
488 }
489
490 newsk = dccp_create_openreq_child(sk, req, skb);
491 if (newsk == NULL)
492 goto out_nonewsk;
493
494 /*
495 * No need to charge this sock to the relevant IPv6 refcnt debug socks
496 * count here, dccp_create_openreq_child now does this for us, see the
497 * comment in that function for the gory details. -acme
498 */
499
500 ip6_dst_store(newsk, dst, NULL, NULL);
501 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
502 NETIF_F_TSO);
503 newdp6 = (struct dccp6_sock *)newsk;
504 newinet = inet_sk(newsk);
505 newinet->pinet6 = &newdp6->inet6;
506 newnp = inet6_sk(newsk);
507
508 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
509
510 newnp->saddr = ireq->ir_v6_loc_addr;
511
512 /* Now IPv6 options...
513
514 First: no IPv4 options.
515 */
516 newinet->inet_opt = NULL;
517
518 /* Clone RX bits */
519 newnp->rxopt.all = np->rxopt.all;
520
521 newnp->ipv6_mc_list = NULL;
522 newnp->ipv6_ac_list = NULL;
523 newnp->ipv6_fl_list = NULL;
524 newnp->pktoptions = NULL;
525 newnp->opt = NULL;
526 newnp->mcast_oif = inet6_iif(skb);
527 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
528
529 /*
530 * Clone native IPv6 options from listening socket (if any)
531 *
532 * Yes, keeping reference count would be much more clever, but we make
533 * one more one thing there: reattach optmem to newsk.
534 */
535 opt = ireq->ipv6_opt;
536 if (!opt)
537 opt = rcu_dereference(np->opt);
538 if (opt) {
539 opt = ipv6_dup_options(newsk, opt);
540 RCU_INIT_POINTER(newnp->opt, opt);
541 }
542 inet_csk(newsk)->icsk_ext_hdr_len = 0;
543 if (opt)
544 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
545 opt->opt_flen;
546
547 dccp_sync_mss(newsk, dst_mtu(dst));
548
549 if (__inet_inherit_port(sk, newsk) < 0) {
550 inet_csk_prepare_forced_close(newsk);
551 dccp_done(newsk);
552 goto out;
553 }
554 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL);
555 /* Clone pktoptions received with SYN, if we own the req */
556 if (*own_req && ireq->pktopts) {
557 newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk);
558 consume_skb(ireq->pktopts);
559 ireq->pktopts = NULL;
560 }
561
562 return newsk;
563
564 out_overflow:
565 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
566 out_nonewsk:
567 dst_release(dst);
568 out:
569 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
570 return NULL;
571 }
572
573 /* The socket must have it's spinlock held when we get
574 * here.
575 *
576 * We have a potential double-lock case here, so even when
577 * doing backlog processing we use the BH locking scheme.
578 * This is because we cannot sleep with the original spinlock
579 * held.
580 */
dccp_v6_do_rcv(struct sock * sk,struct sk_buff * skb)581 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
582 {
583 struct ipv6_pinfo *np = inet6_sk(sk);
584 struct sk_buff *opt_skb = NULL;
585
586 /* Imagine: socket is IPv6. IPv4 packet arrives,
587 goes to IPv4 receive handler and backlogged.
588 From backlog it always goes here. Kerboom...
589 Fortunately, dccp_rcv_established and rcv_established
590 handle them correctly, but it is not case with
591 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK
592 */
593
594 if (skb->protocol == htons(ETH_P_IP))
595 return dccp_v4_do_rcv(sk, skb);
596
597 if (sk_filter(sk, skb))
598 goto discard;
599
600 /*
601 * socket locking is here for SMP purposes as backlog rcv is currently
602 * called with bh processing disabled.
603 */
604
605 /* Do Stevens' IPV6_PKTOPTIONS.
606
607 Yes, guys, it is the only place in our code, where we
608 may make it not affecting IPv4.
609 The rest of code is protocol independent,
610 and I do not like idea to uglify IPv4.
611
612 Actually, all the idea behind IPV6_PKTOPTIONS
613 looks not very well thought. For now we latch
614 options, received in the last packet, enqueued
615 by tcp. Feel free to propose better solution.
616 --ANK (980728)
617 */
618 if (np->rxopt.all && sk->sk_state != DCCP_LISTEN)
619 opt_skb = skb_clone_and_charge_r(skb, sk);
620
621 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
622 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
623 goto reset;
624 if (opt_skb)
625 goto ipv6_pktoptions;
626 return 0;
627 }
628
629 /*
630 * Step 3: Process LISTEN state
631 * If S.state == LISTEN,
632 * If P.type == Request or P contains a valid Init Cookie option,
633 * (* Must scan the packet's options to check for Init
634 * Cookies. Only Init Cookies are processed here,
635 * however; other options are processed in Step 8. This
636 * scan need only be performed if the endpoint uses Init
637 * Cookies *)
638 * (* Generate a new socket and switch to that socket *)
639 * Set S := new socket for this port pair
640 * S.state = RESPOND
641 * Choose S.ISS (initial seqno) or set from Init Cookies
642 * Initialize S.GAR := S.ISS
643 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
644 * Continue with S.state == RESPOND
645 * (* A Response packet will be generated in Step 11 *)
646 * Otherwise,
647 * Generate Reset(No Connection) unless P.type == Reset
648 * Drop packet and return
649 *
650 * NOTE: the check for the packet types is done in
651 * dccp_rcv_state_process
652 */
653
654 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
655 goto reset;
656 if (opt_skb)
657 goto ipv6_pktoptions;
658 return 0;
659
660 reset:
661 dccp_v6_ctl_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED);
662 discard:
663 if (opt_skb != NULL)
664 __kfree_skb(opt_skb);
665 kfree_skb(skb);
666 return 0;
667
668 /* Handling IPV6_PKTOPTIONS skb the similar
669 * way it's done for net/ipv6/tcp_ipv6.c
670 */
671 ipv6_pktoptions:
672 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) {
673 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
674 WRITE_ONCE(np->mcast_oif, inet6_iif(opt_skb));
675 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
676 WRITE_ONCE(np->mcast_hops, ipv6_hdr(opt_skb)->hop_limit);
677 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
678 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
679 if (inet6_test_bit(REPFLOW, sk))
680 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
681 if (ipv6_opt_accepted(sk, opt_skb,
682 &DCCP_SKB_CB(opt_skb)->header.h6)) {
683 memmove(IP6CB(opt_skb),
684 &DCCP_SKB_CB(opt_skb)->header.h6,
685 sizeof(struct inet6_skb_parm));
686 opt_skb = xchg(&np->pktoptions, opt_skb);
687 } else {
688 __kfree_skb(opt_skb);
689 opt_skb = xchg(&np->pktoptions, NULL);
690 }
691 }
692
693 kfree_skb(opt_skb);
694 return 0;
695 }
696
dccp_v6_rcv(struct sk_buff * skb)697 static int dccp_v6_rcv(struct sk_buff *skb)
698 {
699 const struct dccp_hdr *dh;
700 bool refcounted;
701 struct sock *sk;
702 int min_cov;
703
704 /* Step 1: Check header basics */
705
706 if (dccp_invalid_packet(skb))
707 goto discard_it;
708
709 /* Step 1: If header checksum is incorrect, drop packet and return. */
710 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
711 &ipv6_hdr(skb)->daddr)) {
712 DCCP_WARN("dropped packet with invalid checksum\n");
713 goto discard_it;
714 }
715
716 dh = dccp_hdr(skb);
717
718 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
719 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
720
721 if (dccp_packet_without_ack(skb))
722 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
723 else
724 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
725
726 lookup:
727 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
728 dh->dccph_sport, dh->dccph_dport,
729 inet6_iif(skb), 0, &refcounted);
730 if (!sk) {
731 dccp_pr_debug("failed to look up flow ID in table and "
732 "get corresponding socket\n");
733 goto no_dccp_socket;
734 }
735
736 /*
737 * Step 2:
738 * ... or S.state == TIMEWAIT,
739 * Generate Reset(No Connection) unless P.type == Reset
740 * Drop packet and return
741 */
742 if (sk->sk_state == DCCP_TIME_WAIT) {
743 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
744 inet_twsk_put(inet_twsk(sk));
745 goto no_dccp_socket;
746 }
747
748 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
749 struct request_sock *req = inet_reqsk(sk);
750 struct sock *nsk;
751
752 sk = req->rsk_listener;
753 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
754 inet_csk_reqsk_queue_drop_and_put(sk, req);
755 goto lookup;
756 }
757 sock_hold(sk);
758 refcounted = true;
759 nsk = dccp_check_req(sk, skb, req);
760 if (!nsk) {
761 reqsk_put(req);
762 goto discard_and_relse;
763 }
764 if (nsk == sk) {
765 reqsk_put(req);
766 } else if (dccp_child_process(sk, nsk, skb)) {
767 dccp_v6_ctl_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED);
768 goto discard_and_relse;
769 } else {
770 sock_put(sk);
771 return 0;
772 }
773 }
774 /*
775 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
776 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
777 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
778 */
779 min_cov = dccp_sk(sk)->dccps_pcrlen;
780 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
781 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
782 dh->dccph_cscov, min_cov);
783 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
784 goto discard_and_relse;
785 }
786
787 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
788 goto discard_and_relse;
789 nf_reset_ct(skb);
790
791 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4,
792 refcounted) ? -1 : 0;
793
794 no_dccp_socket:
795 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
796 goto discard_it;
797 /*
798 * Step 2:
799 * If no socket ...
800 * Generate Reset(No Connection) unless P.type == Reset
801 * Drop packet and return
802 */
803 if (dh->dccph_type != DCCP_PKT_RESET) {
804 DCCP_SKB_CB(skb)->dccpd_reset_code =
805 DCCP_RESET_CODE_NO_CONNECTION;
806 dccp_v6_ctl_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED);
807 }
808
809 discard_it:
810 kfree_skb(skb);
811 return 0;
812
813 discard_and_relse:
814 if (refcounted)
815 sock_put(sk);
816 goto discard_it;
817 }
818
dccp_v6_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)819 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
820 int addr_len)
821 {
822 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
823 struct inet_connection_sock *icsk = inet_csk(sk);
824 struct inet_sock *inet = inet_sk(sk);
825 struct ipv6_pinfo *np = inet6_sk(sk);
826 struct dccp_sock *dp = dccp_sk(sk);
827 struct in6_addr *saddr = NULL, *final_p, final;
828 struct ipv6_txoptions *opt;
829 struct flowi6 fl6;
830 struct dst_entry *dst;
831 int addr_type;
832 int err;
833
834 dp->dccps_role = DCCP_ROLE_CLIENT;
835
836 if (addr_len < SIN6_LEN_RFC2133)
837 return -EINVAL;
838
839 if (usin->sin6_family != AF_INET6)
840 return -EAFNOSUPPORT;
841
842 memset(&fl6, 0, sizeof(fl6));
843
844 if (inet6_test_bit(SNDFLOW, sk)) {
845 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
846 IP6_ECN_flow_init(fl6.flowlabel);
847 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
848 struct ip6_flowlabel *flowlabel;
849 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
850 if (IS_ERR(flowlabel))
851 return -EINVAL;
852 fl6_sock_release(flowlabel);
853 }
854 }
855 /*
856 * connect() to INADDR_ANY means loopback (BSD'ism).
857 */
858 if (ipv6_addr_any(&usin->sin6_addr))
859 usin->sin6_addr.s6_addr[15] = 1;
860
861 addr_type = ipv6_addr_type(&usin->sin6_addr);
862
863 if (addr_type & IPV6_ADDR_MULTICAST)
864 return -ENETUNREACH;
865
866 if (addr_type & IPV6_ADDR_LINKLOCAL) {
867 if (addr_len >= sizeof(struct sockaddr_in6) &&
868 usin->sin6_scope_id) {
869 /* If interface is set while binding, indices
870 * must coincide.
871 */
872 if (sk->sk_bound_dev_if &&
873 sk->sk_bound_dev_if != usin->sin6_scope_id)
874 return -EINVAL;
875
876 sk->sk_bound_dev_if = usin->sin6_scope_id;
877 }
878
879 /* Connect to link-local address requires an interface */
880 if (!sk->sk_bound_dev_if)
881 return -EINVAL;
882 }
883
884 sk->sk_v6_daddr = usin->sin6_addr;
885 np->flow_label = fl6.flowlabel;
886
887 /*
888 * DCCP over IPv4
889 */
890 if (addr_type == IPV6_ADDR_MAPPED) {
891 u32 exthdrlen = icsk->icsk_ext_hdr_len;
892 struct sockaddr_in sin;
893
894 net_dbg_ratelimited("connect: ipv4 mapped\n");
895
896 if (ipv6_only_sock(sk))
897 return -ENETUNREACH;
898
899 sin.sin_family = AF_INET;
900 sin.sin_port = usin->sin6_port;
901 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
902
903 icsk->icsk_af_ops = &dccp_ipv6_mapped;
904 sk->sk_backlog_rcv = dccp_v4_do_rcv;
905
906 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
907 if (err) {
908 icsk->icsk_ext_hdr_len = exthdrlen;
909 icsk->icsk_af_ops = &dccp_ipv6_af_ops;
910 sk->sk_backlog_rcv = dccp_v6_do_rcv;
911 goto failure;
912 }
913 np->saddr = sk->sk_v6_rcv_saddr;
914 return err;
915 }
916
917 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
918 saddr = &sk->sk_v6_rcv_saddr;
919
920 fl6.flowi6_proto = IPPROTO_DCCP;
921 fl6.daddr = sk->sk_v6_daddr;
922 fl6.saddr = saddr ? *saddr : np->saddr;
923 fl6.flowi6_oif = sk->sk_bound_dev_if;
924 fl6.fl6_dport = usin->sin6_port;
925 fl6.fl6_sport = inet->inet_sport;
926 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
927
928 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
929 final_p = fl6_update_dst(&fl6, opt, &final);
930
931 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
932 if (IS_ERR(dst)) {
933 err = PTR_ERR(dst);
934 goto failure;
935 }
936
937 if (saddr == NULL) {
938 saddr = &fl6.saddr;
939
940 err = inet_bhash2_update_saddr(sk, saddr, AF_INET6);
941 if (err)
942 goto failure;
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 (opt)
953 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
954
955 inet->inet_dport = usin->sin6_port;
956
957 dccp_set_state(sk, DCCP_REQUESTING);
958 err = inet6_hash_connect(&dccp_death_row, sk);
959 if (err)
960 goto late_failure;
961
962 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
963 sk->sk_v6_daddr.s6_addr32,
964 inet->inet_sport,
965 inet->inet_dport);
966 err = dccp_connect(sk);
967 if (err)
968 goto late_failure;
969
970 return 0;
971
972 late_failure:
973 dccp_set_state(sk, DCCP_CLOSED);
974 inet_bhash2_reset_saddr(sk);
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 };
992
993 /*
994 * DCCP over IPv4 via INET6 API
995 */
996 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
997 .queue_xmit = ip_queue_xmit,
998 .send_check = dccp_v4_send_check,
999 .rebuild_header = inet_sk_rebuild_header,
1000 .conn_request = dccp_v6_conn_request,
1001 .syn_recv_sock = dccp_v6_request_recv_sock,
1002 .net_header_len = sizeof(struct iphdr),
1003 .setsockopt = ipv6_setsockopt,
1004 .getsockopt = ipv6_getsockopt,
1005 };
1006
dccp_v6_sk_destruct(struct sock * sk)1007 static void dccp_v6_sk_destruct(struct sock *sk)
1008 {
1009 dccp_destruct_common(sk);
1010 inet6_sock_destruct(sk);
1011 }
1012
1013 /* NOTE: A lot of things set to zero explicitly by call to
1014 * sk_alloc() so need not be done here.
1015 */
dccp_v6_init_sock(struct sock * sk)1016 static int dccp_v6_init_sock(struct sock *sk)
1017 {
1018 static __u8 dccp_v6_ctl_sock_initialized;
1019 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
1020
1021 if (err == 0) {
1022 if (unlikely(!dccp_v6_ctl_sock_initialized))
1023 dccp_v6_ctl_sock_initialized = 1;
1024 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
1025 sk->sk_destruct = dccp_v6_sk_destruct;
1026 }
1027
1028 return err;
1029 }
1030
1031 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
1032 .twsk_obj_size = sizeof(struct dccp6_timewait_sock),
1033 };
1034
1035 static struct proto dccp_v6_prot = {
1036 .name = "DCCPv6",
1037 .owner = THIS_MODULE,
1038 .close = dccp_close,
1039 .connect = dccp_v6_connect,
1040 .disconnect = dccp_disconnect,
1041 .ioctl = dccp_ioctl,
1042 .init = dccp_v6_init_sock,
1043 .setsockopt = dccp_setsockopt,
1044 .getsockopt = dccp_getsockopt,
1045 .sendmsg = dccp_sendmsg,
1046 .recvmsg = dccp_recvmsg,
1047 .backlog_rcv = dccp_v6_do_rcv,
1048 .hash = inet6_hash,
1049 .unhash = inet_unhash,
1050 .accept = inet_csk_accept,
1051 .get_port = inet_csk_get_port,
1052 .shutdown = dccp_shutdown,
1053 .destroy = dccp_destroy_sock,
1054 .orphan_count = &dccp_orphan_count,
1055 .max_header = MAX_DCCP_HEADER,
1056 .obj_size = sizeof(struct dccp6_sock),
1057 .ipv6_pinfo_offset = offsetof(struct dccp6_sock, inet6),
1058 .slab_flags = SLAB_TYPESAFE_BY_RCU,
1059 .rsk_prot = &dccp6_request_sock_ops,
1060 .twsk_prot = &dccp6_timewait_sock_ops,
1061 .h.hashinfo = &dccp_hashinfo,
1062 };
1063
1064 static const struct inet6_protocol dccp_v6_protocol = {
1065 .handler = dccp_v6_rcv,
1066 .err_handler = dccp_v6_err,
1067 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1068 };
1069
1070 static const struct proto_ops inet6_dccp_ops = {
1071 .family = PF_INET6,
1072 .owner = THIS_MODULE,
1073 .release = inet6_release,
1074 .bind = inet6_bind,
1075 .connect = inet_stream_connect,
1076 .socketpair = sock_no_socketpair,
1077 .accept = inet_accept,
1078 .getname = inet6_getname,
1079 .poll = dccp_poll,
1080 .ioctl = inet6_ioctl,
1081 .gettstamp = sock_gettstamp,
1082 .listen = inet_dccp_listen,
1083 .shutdown = inet_shutdown,
1084 .setsockopt = sock_common_setsockopt,
1085 .getsockopt = sock_common_getsockopt,
1086 .sendmsg = inet_sendmsg,
1087 .recvmsg = sock_common_recvmsg,
1088 .mmap = sock_no_mmap,
1089 #ifdef CONFIG_COMPAT
1090 .compat_ioctl = inet6_compat_ioctl,
1091 #endif
1092 };
1093
1094 static struct inet_protosw dccp_v6_protosw = {
1095 .type = SOCK_DCCP,
1096 .protocol = IPPROTO_DCCP,
1097 .prot = &dccp_v6_prot,
1098 .ops = &inet6_dccp_ops,
1099 .flags = INET_PROTOSW_ICSK,
1100 };
1101
dccp_v6_init_net(struct net * net)1102 static int __net_init dccp_v6_init_net(struct net *net)
1103 {
1104 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id);
1105
1106 if (dccp_hashinfo.bhash == NULL)
1107 return -ESOCKTNOSUPPORT;
1108
1109 return inet_ctl_sock_create(&pn->v6_ctl_sk, PF_INET6,
1110 SOCK_DCCP, IPPROTO_DCCP, net);
1111 }
1112
dccp_v6_exit_net(struct net * net)1113 static void __net_exit dccp_v6_exit_net(struct net *net)
1114 {
1115 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id);
1116
1117 inet_ctl_sock_destroy(pn->v6_ctl_sk);
1118 }
1119
1120 static struct pernet_operations dccp_v6_ops = {
1121 .init = dccp_v6_init_net,
1122 .exit = dccp_v6_exit_net,
1123 .id = &dccp_v6_pernet_id,
1124 .size = sizeof(struct dccp_v6_pernet),
1125 };
1126
dccp_v6_init(void)1127 static int __init dccp_v6_init(void)
1128 {
1129 int err = proto_register(&dccp_v6_prot, 1);
1130
1131 if (err)
1132 goto out;
1133
1134 inet6_register_protosw(&dccp_v6_protosw);
1135
1136 err = register_pernet_subsys(&dccp_v6_ops);
1137 if (err)
1138 goto out_destroy_ctl_sock;
1139
1140 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1141 if (err)
1142 goto out_unregister_proto;
1143
1144 out:
1145 return err;
1146 out_unregister_proto:
1147 unregister_pernet_subsys(&dccp_v6_ops);
1148 out_destroy_ctl_sock:
1149 inet6_unregister_protosw(&dccp_v6_protosw);
1150 proto_unregister(&dccp_v6_prot);
1151 goto out;
1152 }
1153
dccp_v6_exit(void)1154 static void __exit dccp_v6_exit(void)
1155 {
1156 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1157 unregister_pernet_subsys(&dccp_v6_ops);
1158 inet6_unregister_protosw(&dccp_v6_protosw);
1159 proto_unregister(&dccp_v6_prot);
1160 }
1161
1162 module_init(dccp_v6_init);
1163 module_exit(dccp_v6_exit);
1164
1165 /*
1166 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1167 * values directly, Also cover the case where the protocol is not specified,
1168 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1169 */
1170 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1171 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1172 MODULE_LICENSE("GPL");
1173 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1174 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");
1175