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Linux 4.19.133
[linux/fpc-iii.git] / net / dccp / ipv6.c
blobb438bed6749d47b9103c3c1cea1d1d7056e5c2fc
1 /*
2 * DCCP over IPv6
3 * Linux INET6 implementation
4 *
5 * Based on net/dccp6/ipv6.c
6 *
7 * Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14
15 #include <linux/module.h>
16 #include <linux/random.h>
17 #include <linux/slab.h>
18 #include <linux/xfrm.h>
19 #include <linux/string.h>
20
21 #include <net/addrconf.h>
22 #include <net/inet_common.h>
23 #include <net/inet_hashtables.h>
24 #include <net/inet_sock.h>
25 #include <net/inet6_connection_sock.h>
26 #include <net/inet6_hashtables.h>
27 #include <net/ip6_route.h>
28 #include <net/ipv6.h>
29 #include <net/protocol.h>
30 #include <net/transp_v6.h>
31 #include <net/ip6_checksum.h>
32 #include <net/xfrm.h>
33 #include <net/secure_seq.h>
34 #include <net/sock.h>
35
36 #include "dccp.h"
37 #include "ipv6.h"
38 #include "feat.h"
39
40 /* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */
41
42 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
43 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
44
45 /* add pseudo-header to DCCP checksum stored in skb->csum */
46 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
47 const struct in6_addr *saddr,
48 const struct in6_addr *daddr)
49 {
50 return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
51 }
52
53 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
54 {
55 struct ipv6_pinfo *np = inet6_sk(sk);
56 struct dccp_hdr *dh = dccp_hdr(skb);
57
58 dccp_csum_outgoing(skb);
59 dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
60 }
61
62 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
63 {
64 return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
65 ipv6_hdr(skb)->saddr.s6_addr32,
66 dccp_hdr(skb)->dccph_dport,
67 dccp_hdr(skb)->dccph_sport );
68
69 }
70
71 static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
72 u8 type, u8 code, int offset, __be32 info)
73 {
74 const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
75 const struct dccp_hdr *dh;
76 struct dccp_sock *dp;
77 struct ipv6_pinfo *np;
78 struct sock *sk;
79 int err;
80 __u64 seq;
81 struct net *net = dev_net(skb->dev);
82
83 /* Only need dccph_dport & dccph_sport which are the first
84 * 4 bytes in dccp header.
85 * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
86 */
87 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
88 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
89 dh = (struct dccp_hdr *)(skb->data + offset);
90
91 sk = __inet6_lookup_established(net, &dccp_hashinfo,
92 &hdr->daddr, dh->dccph_dport,
93 &hdr->saddr, ntohs(dh->dccph_sport),
94 inet6_iif(skb), 0);
95
96 if (!sk) {
97 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
98 ICMP6_MIB_INERRORS);
99 return;
100 }
101
102 if (sk->sk_state == DCCP_TIME_WAIT) {
103 inet_twsk_put(inet_twsk(sk));
104 return;
105 }
106 seq = dccp_hdr_seq(dh);
107 if (sk->sk_state == DCCP_NEW_SYN_RECV)
108 return dccp_req_err(sk, seq);
109
110 bh_lock_sock(sk);
111 if (sock_owned_by_user(sk))
112 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
113
114 if (sk->sk_state == DCCP_CLOSED)
115 goto out;
116
117 dp = dccp_sk(sk);
118 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
119 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
120 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
121 goto out;
122 }
123
124 np = inet6_sk(sk);
125
126 if (type == NDISC_REDIRECT) {
127 if (!sock_owned_by_user(sk)) {
128 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
129
130 if (dst)
131 dst->ops->redirect(dst, sk, skb);
132 }
133 goto out;
134 }
135
136 if (type == ICMPV6_PKT_TOOBIG) {
137 struct dst_entry *dst = NULL;
138
139 if (!ip6_sk_accept_pmtu(sk))
140 goto out;
141
142 if (sock_owned_by_user(sk))
143 goto out;
144 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
145 goto out;
146
147 dst = inet6_csk_update_pmtu(sk, ntohl(info));
148 if (!dst)
149 goto out;
150
151 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
152 dccp_sync_mss(sk, dst_mtu(dst));
153 goto out;
154 }
155
156 icmpv6_err_convert(type, code, &err);
157
158 /* Might be for an request_sock */
159 switch (sk->sk_state) {
160 case DCCP_REQUESTING:
161 case DCCP_RESPOND: /* Cannot happen.
162 It can, it SYNs are crossed. --ANK */
163 if (!sock_owned_by_user(sk)) {
164 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
165 sk->sk_err = err;
166 /*
167 * Wake people up to see the error
168 * (see connect in sock.c)
169 */
170 sk->sk_error_report(sk);
171 dccp_done(sk);
172 } else
173 sk->sk_err_soft = err;
174 goto out;
175 }
176
177 if (!sock_owned_by_user(sk) && np->recverr) {
178 sk->sk_err = err;
179 sk->sk_error_report(sk);
180 } else
181 sk->sk_err_soft = err;
182
183 out:
184 bh_unlock_sock(sk);
185 sock_put(sk);
186 }
187
188
189 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
190 {
191 struct inet_request_sock *ireq = inet_rsk(req);
192 struct ipv6_pinfo *np = inet6_sk(sk);
193 struct sk_buff *skb;
194 struct in6_addr *final_p, final;
195 struct flowi6 fl6;
196 int err = -1;
197 struct dst_entry *dst;
198
199 memset(&fl6, 0, sizeof(fl6));
200 fl6.flowi6_proto = IPPROTO_DCCP;
201 fl6.daddr = ireq->ir_v6_rmt_addr;
202 fl6.saddr = ireq->ir_v6_loc_addr;
203 fl6.flowlabel = 0;
204 fl6.flowi6_oif = ireq->ir_iif;
205 fl6.fl6_dport = ireq->ir_rmt_port;
206 fl6.fl6_sport = htons(ireq->ir_num);
207 security_req_classify_flow(req, flowi6_to_flowi(&fl6));
208
209
210 rcu_read_lock();
211 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
212 rcu_read_unlock();
213
214 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
215 if (IS_ERR(dst)) {
216 err = PTR_ERR(dst);
217 dst = NULL;
218 goto done;
219 }
220
221 skb = dccp_make_response(sk, dst, req);
222 if (skb != NULL) {
223 struct dccp_hdr *dh = dccp_hdr(skb);
224 struct ipv6_txoptions *opt;
225
226 dh->dccph_checksum = dccp_v6_csum_finish(skb,
227 &ireq->ir_v6_loc_addr,
228 &ireq->ir_v6_rmt_addr);
229 fl6.daddr = ireq->ir_v6_rmt_addr;
230 rcu_read_lock();
231 opt = ireq->ipv6_opt;
232 if (!opt)
233 opt = rcu_dereference(np->opt);
234 err = ip6_xmit(sk, skb, &fl6, sk->sk_mark, opt, np->tclass);
235 rcu_read_unlock();
236 err = net_xmit_eval(err);
237 }
238
239 done:
240 dst_release(dst);
241 return err;
242 }
243
244 static void dccp_v6_reqsk_destructor(struct request_sock *req)
245 {
246 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
247 kfree(inet_rsk(req)->ipv6_opt);
248 kfree_skb(inet_rsk(req)->pktopts);
249 }
250
251 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
252 {
253 const struct ipv6hdr *rxip6h;
254 struct sk_buff *skb;
255 struct flowi6 fl6;
256 struct net *net = dev_net(skb_dst(rxskb)->dev);
257 struct sock *ctl_sk = net->dccp.v6_ctl_sk;
258 struct dst_entry *dst;
259
260 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
261 return;
262
263 if (!ipv6_unicast_destination(rxskb))
264 return;
265
266 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
267 if (skb == NULL)
268 return;
269
270 rxip6h = ipv6_hdr(rxskb);
271 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
272 &rxip6h->daddr);
273
274 memset(&fl6, 0, sizeof(fl6));
275 fl6.daddr = rxip6h->saddr;
276 fl6.saddr = rxip6h->daddr;
277
278 fl6.flowi6_proto = IPPROTO_DCCP;
279 fl6.flowi6_oif = inet6_iif(rxskb);
280 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
281 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
282 security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
283
284 /* sk = NULL, but it is safe for now. RST socket required. */
285 dst = ip6_dst_lookup_flow(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);
289 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
290 DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
291 return;
292 }
293
294 kfree_skb(skb);
295 }
296
297 static struct request_sock_ops dccp6_request_sock_ops = {
298 .family = AF_INET6,
299 .obj_size = sizeof(struct dccp6_request_sock),
300 .rtx_syn_ack = dccp_v6_send_response,
301 .send_ack = dccp_reqsk_send_ack,
302 .destructor = dccp_v6_reqsk_destructor,
303 .send_reset = dccp_v6_ctl_send_reset,
304 .syn_ack_timeout = dccp_syn_ack_timeout,
305 };
306
307 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
308 {
309 struct request_sock *req;
310 struct dccp_request_sock *dreq;
311 struct inet_request_sock *ireq;
312 struct ipv6_pinfo *np = inet6_sk(sk);
313 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
314 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
315
316 if (skb->protocol == htons(ETH_P_IP))
317 return dccp_v4_conn_request(sk, skb);
318
319 if (!ipv6_unicast_destination(skb))
320 return 0; /* discard, don't send a reset here */
321
322 if (dccp_bad_service_code(sk, service)) {
323 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
324 goto drop;
325 }
326 /*
327 * There are no SYN attacks on IPv6, yet...
328 */
329 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
330 if (inet_csk_reqsk_queue_is_full(sk))
331 goto drop;
332
333 if (sk_acceptq_is_full(sk))
334 goto drop;
335
336 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
337 if (req == NULL)
338 goto drop;
339
340 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
341 goto drop_and_free;
342
343 dreq = dccp_rsk(req);
344 if (dccp_parse_options(sk, dreq, skb))
345 goto drop_and_free;
346
347 if (security_inet_conn_request(sk, skb, req))
348 goto drop_and_free;
349
350 ireq = inet_rsk(req);
351 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
352 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
353 ireq->ireq_family = AF_INET6;
354 ireq->ir_mark = inet_request_mark(sk, skb);
355
356 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
357 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
358 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
359 refcount_inc(&skb->users);
360 ireq->pktopts = skb;
361 }
362 ireq->ir_iif = sk->sk_bound_dev_if;
363
364 /* So that link locals have meaning */
365 if (!sk->sk_bound_dev_if &&
366 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
367 ireq->ir_iif = inet6_iif(skb);
368
369 /*
370 * Step 3: Process LISTEN state
371 *
372 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
373 *
374 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
375 */
376 dreq->dreq_isr = dcb->dccpd_seq;
377 dreq->dreq_gsr = dreq->dreq_isr;
378 dreq->dreq_iss = dccp_v6_init_sequence(skb);
379 dreq->dreq_gss = dreq->dreq_iss;
380 dreq->dreq_service = service;
381
382 if (dccp_v6_send_response(sk, req))
383 goto drop_and_free;
384
385 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
386 reqsk_put(req);
387 return 0;
388
389 drop_and_free:
390 reqsk_free(req);
391 drop:
392 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
393 return -1;
394 }
395
396 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
397 struct sk_buff *skb,
398 struct request_sock *req,
399 struct dst_entry *dst,
400 struct request_sock *req_unhash,
401 bool *own_req)
402 {
403 struct inet_request_sock *ireq = inet_rsk(req);
404 struct ipv6_pinfo *newnp;
405 const struct ipv6_pinfo *np = inet6_sk(sk);
406 struct ipv6_txoptions *opt;
407 struct inet_sock *newinet;
408 struct dccp6_sock *newdp6;
409 struct sock *newsk;
410
411 if (skb->protocol == htons(ETH_P_IP)) {
412 /*
413 * v6 mapped
414 */
415 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
416 req_unhash, own_req);
417 if (newsk == NULL)
418 return NULL;
419
420 newdp6 = (struct dccp6_sock *)newsk;
421 newinet = inet_sk(newsk);
422 newinet->pinet6 = &newdp6->inet6;
423 newnp = inet6_sk(newsk);
424
425 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
426
427 newnp->saddr = newsk->sk_v6_rcv_saddr;
428
429 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
430 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
431 newnp->pktoptions = NULL;
432 newnp->opt = NULL;
433 newnp->ipv6_mc_list = NULL;
434 newnp->ipv6_ac_list = NULL;
435 newnp->ipv6_fl_list = NULL;
436 newnp->mcast_oif = inet_iif(skb);
437 newnp->mcast_hops = ip_hdr(skb)->ttl;
438
439 /*
440 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
441 * here, dccp_create_openreq_child now does this for us, see the comment in
442 * that function for the gory details. -acme
443 */
444
445 /* It is tricky place. Until this moment IPv4 tcp
446 worked with IPv6 icsk.icsk_af_ops.
447 Sync it now.
448 */
449 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
450
451 return newsk;
452 }
453
454
455 if (sk_acceptq_is_full(sk))
456 goto out_overflow;
457
458 if (!dst) {
459 struct flowi6 fl6;
460
461 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
462 if (!dst)
463 goto out;
464 }
465
466 newsk = dccp_create_openreq_child(sk, req, skb);
467 if (newsk == NULL)
468 goto out_nonewsk;
469
470 /*
471 * No need to charge this sock to the relevant IPv6 refcnt debug socks
472 * count here, dccp_create_openreq_child now does this for us, see the
473 * comment in that function for the gory details. -acme
474 */
475
476 ip6_dst_store(newsk, dst, NULL, NULL);
477 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
478 NETIF_F_TSO);
479 newdp6 = (struct dccp6_sock *)newsk;
480 newinet = inet_sk(newsk);
481 newinet->pinet6 = &newdp6->inet6;
482 newnp = inet6_sk(newsk);
483
484 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
485
486 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
487 newnp->saddr = ireq->ir_v6_loc_addr;
488 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
489 newsk->sk_bound_dev_if = ireq->ir_iif;
490
491 /* Now IPv6 options...
492
493 First: no IPv4 options.
494 */
495 newinet->inet_opt = NULL;
496
497 /* Clone RX bits */
498 newnp->rxopt.all = np->rxopt.all;
499
500 newnp->ipv6_mc_list = NULL;
501 newnp->ipv6_ac_list = NULL;
502 newnp->ipv6_fl_list = NULL;
503 newnp->pktoptions = NULL;
504 newnp->opt = NULL;
505 newnp->mcast_oif = inet6_iif(skb);
506 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
507
508 /*
509 * Clone native IPv6 options from listening socket (if any)
510 *
511 * Yes, keeping reference count would be much more clever, but we make
512 * one more one thing there: reattach optmem to newsk.
513 */
514 opt = ireq->ipv6_opt;
515 if (!opt)
516 opt = rcu_dereference(np->opt);
517 if (opt) {
518 opt = ipv6_dup_options(newsk, opt);
519 RCU_INIT_POINTER(newnp->opt, opt);
520 }
521 inet_csk(newsk)->icsk_ext_hdr_len = 0;
522 if (opt)
523 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
524 opt->opt_flen;
525
526 dccp_sync_mss(newsk, dst_mtu(dst));
527
528 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
529 newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
530
531 if (__inet_inherit_port(sk, newsk) < 0) {
532 inet_csk_prepare_forced_close(newsk);
533 dccp_done(newsk);
534 goto out;
535 }
536 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
537 /* Clone pktoptions received with SYN, if we own the req */
538 if (*own_req && ireq->pktopts) {
539 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
540 consume_skb(ireq->pktopts);
541 ireq->pktopts = NULL;
542 if (newnp->pktoptions)
543 skb_set_owner_r(newnp->pktoptions, newsk);
544 }
545
546 return newsk;
547
548 out_overflow:
549 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
550 out_nonewsk:
551 dst_release(dst);
552 out:
553 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
554 return NULL;
555 }
556
557 /* The socket must have it's spinlock held when we get
558 * here.
559 *
560 * We have a potential double-lock case here, so even when
561 * doing backlog processing we use the BH locking scheme.
562 * This is because we cannot sleep with the original spinlock
563 * held.
564 */
565 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
566 {
567 struct ipv6_pinfo *np = inet6_sk(sk);
568 struct sk_buff *opt_skb = NULL;
569
570 /* Imagine: socket is IPv6. IPv4 packet arrives,
571 goes to IPv4 receive handler and backlogged.
572 From backlog it always goes here. Kerboom...
573 Fortunately, dccp_rcv_established and rcv_established
574 handle them correctly, but it is not case with
575 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK
576 */
577
578 if (skb->protocol == htons(ETH_P_IP))
579 return dccp_v4_do_rcv(sk, skb);
580
581 if (sk_filter(sk, skb))
582 goto discard;
583
584 /*
585 * socket locking is here for SMP purposes as backlog rcv is currently
586 * called with bh processing disabled.
587 */
588
589 /* Do Stevens' IPV6_PKTOPTIONS.
590
591 Yes, guys, it is the only place in our code, where we
592 may make it not affecting IPv4.
593 The rest of code is protocol independent,
594 and I do not like idea to uglify IPv4.
595
596 Actually, all the idea behind IPV6_PKTOPTIONS
597 looks not very well thought. For now we latch
598 options, received in the last packet, enqueued
599 by tcp. Feel free to propose better solution.
600 --ANK (980728)
601 */
602 if (np->rxopt.all)
603 opt_skb = skb_clone(skb, GFP_ATOMIC);
604
605 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
606 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
607 goto reset;
608 if (opt_skb)
609 goto ipv6_pktoptions;
610 return 0;
611 }
612
613 /*
614 * Step 3: Process LISTEN state
615 * If S.state == LISTEN,
616 * If P.type == Request or P contains a valid Init Cookie option,
617 * (* Must scan the packet's options to check for Init
618 * Cookies. Only Init Cookies are processed here,
619 * however; other options are processed in Step 8. This
620 * scan need only be performed if the endpoint uses Init
621 * Cookies *)
622 * (* Generate a new socket and switch to that socket *)
623 * Set S := new socket for this port pair
624 * S.state = RESPOND
625 * Choose S.ISS (initial seqno) or set from Init Cookies
626 * Initialize S.GAR := S.ISS
627 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
628 * Continue with S.state == RESPOND
629 * (* A Response packet will be generated in Step 11 *)
630 * Otherwise,
631 * Generate Reset(No Connection) unless P.type == Reset
632 * Drop packet and return
633 *
634 * NOTE: the check for the packet types is done in
635 * dccp_rcv_state_process
636 */
637
638 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
639 goto reset;
640 if (opt_skb)
641 goto ipv6_pktoptions;
642 return 0;
643
644 reset:
645 dccp_v6_ctl_send_reset(sk, skb);
646 discard:
647 if (opt_skb != NULL)
648 __kfree_skb(opt_skb);
649 kfree_skb(skb);
650 return 0;
651
652 /* Handling IPV6_PKTOPTIONS skb the similar
653 * way it's done for net/ipv6/tcp_ipv6.c
654 */
655 ipv6_pktoptions:
656 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) {
657 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
658 np->mcast_oif = inet6_iif(opt_skb);
659 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
660 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
661 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
662 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
663 if (np->repflow)
664 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
665 if (ipv6_opt_accepted(sk, opt_skb,
666 &DCCP_SKB_CB(opt_skb)->header.h6)) {
667 skb_set_owner_r(opt_skb, sk);
668 memmove(IP6CB(opt_skb),
669 &DCCP_SKB_CB(opt_skb)->header.h6,
670 sizeof(struct inet6_skb_parm));
671 opt_skb = xchg(&np->pktoptions, opt_skb);
672 } else {
673 __kfree_skb(opt_skb);
674 opt_skb = xchg(&np->pktoptions, NULL);
675 }
676 }
677
678 kfree_skb(opt_skb);
679 return 0;
680 }
681
682 static int dccp_v6_rcv(struct sk_buff *skb)
683 {
684 const struct dccp_hdr *dh;
685 bool refcounted;
686 struct sock *sk;
687 int min_cov;
688
689 /* Step 1: Check header basics */
690
691 if (dccp_invalid_packet(skb))
692 goto discard_it;
693
694 /* Step 1: If header checksum is incorrect, drop packet and return. */
695 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
696 &ipv6_hdr(skb)->daddr)) {
697 DCCP_WARN("dropped packet with invalid checksum\n");
698 goto discard_it;
699 }
700
701 dh = dccp_hdr(skb);
702
703 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
704 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
705
706 if (dccp_packet_without_ack(skb))
707 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
708 else
709 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
710
711 lookup:
712 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
713 dh->dccph_sport, dh->dccph_dport,
714 inet6_iif(skb), 0, &refcounted);
715 if (!sk) {
716 dccp_pr_debug("failed to look up flow ID in table and "
717 "get corresponding socket\n");
718 goto no_dccp_socket;
719 }
720
721 /*
722 * Step 2:
723 * ... or S.state == TIMEWAIT,
724 * Generate Reset(No Connection) unless P.type == Reset
725 * Drop packet and return
726 */
727 if (sk->sk_state == DCCP_TIME_WAIT) {
728 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
729 inet_twsk_put(inet_twsk(sk));
730 goto no_dccp_socket;
731 }
732
733 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
734 struct request_sock *req = inet_reqsk(sk);
735 struct sock *nsk;
736
737 sk = req->rsk_listener;
738 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
739 inet_csk_reqsk_queue_drop_and_put(sk, req);
740 goto lookup;
741 }
742 sock_hold(sk);
743 refcounted = true;
744 nsk = dccp_check_req(sk, skb, req);
745 if (!nsk) {
746 reqsk_put(req);
747 goto discard_and_relse;
748 }
749 if (nsk == sk) {
750 reqsk_put(req);
751 } else if (dccp_child_process(sk, nsk, skb)) {
752 dccp_v6_ctl_send_reset(sk, skb);
753 goto discard_and_relse;
754 } else {
755 sock_put(sk);
756 return 0;
757 }
758 }
759 /*
760 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
761 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
762 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
763 */
764 min_cov = dccp_sk(sk)->dccps_pcrlen;
765 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
766 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
767 dh->dccph_cscov, min_cov);
768 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
769 goto discard_and_relse;
770 }
771
772 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
773 goto discard_and_relse;
774
775 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4,
776 refcounted) ? -1 : 0;
777
778 no_dccp_socket:
779 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
780 goto discard_it;
781 /*
782 * Step 2:
783 * If no socket ...
784 * Generate Reset(No Connection) unless P.type == Reset
785 * Drop packet and return
786 */
787 if (dh->dccph_type != DCCP_PKT_RESET) {
788 DCCP_SKB_CB(skb)->dccpd_reset_code =
789 DCCP_RESET_CODE_NO_CONNECTION;
790 dccp_v6_ctl_send_reset(sk, skb);
791 }
792
793 discard_it:
794 kfree_skb(skb);
795 return 0;
796
797 discard_and_relse:
798 if (refcounted)
799 sock_put(sk);
800 goto discard_it;
801 }
802
803 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
804 int addr_len)
805 {
806 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
807 struct inet_connection_sock *icsk = inet_csk(sk);
808 struct inet_sock *inet = inet_sk(sk);
809 struct ipv6_pinfo *np = inet6_sk(sk);
810 struct dccp_sock *dp = dccp_sk(sk);
811 struct in6_addr *saddr = NULL, *final_p, final;
812 struct ipv6_txoptions *opt;
813 struct flowi6 fl6;
814 struct dst_entry *dst;
815 int addr_type;
816 int err;
817
818 dp->dccps_role = DCCP_ROLE_CLIENT;
819
820 if (addr_len < SIN6_LEN_RFC2133)
821 return -EINVAL;
822
823 if (usin->sin6_family != AF_INET6)
824 return -EAFNOSUPPORT;
825
826 memset(&fl6, 0, sizeof(fl6));
827
828 if (np->sndflow) {
829 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
830 IP6_ECN_flow_init(fl6.flowlabel);
831 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
832 struct ip6_flowlabel *flowlabel;
833 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
834 if (flowlabel == NULL)
835 return -EINVAL;
836 fl6_sock_release(flowlabel);
837 }
838 }
839 /*
840 * connect() to INADDR_ANY means loopback (BSD'ism).
841 */
842 if (ipv6_addr_any(&usin->sin6_addr))
843 usin->sin6_addr.s6_addr[15] = 1;
844
845 addr_type = ipv6_addr_type(&usin->sin6_addr);
846
847 if (addr_type & IPV6_ADDR_MULTICAST)
848 return -ENETUNREACH;
849
850 if (addr_type & IPV6_ADDR_LINKLOCAL) {
851 if (addr_len >= sizeof(struct sockaddr_in6) &&
852 usin->sin6_scope_id) {
853 /* If interface is set while binding, indices
854 * must coincide.
855 */
856 if (sk->sk_bound_dev_if &&
857 sk->sk_bound_dev_if != usin->sin6_scope_id)
858 return -EINVAL;
859
860 sk->sk_bound_dev_if = usin->sin6_scope_id;
861 }
862
863 /* Connect to link-local address requires an interface */
864 if (!sk->sk_bound_dev_if)
865 return -EINVAL;
866 }
867
868 sk->sk_v6_daddr = usin->sin6_addr;
869 np->flow_label = fl6.flowlabel;
870
871 /*
872 * DCCP over IPv4
873 */
874 if (addr_type == IPV6_ADDR_MAPPED) {
875 u32 exthdrlen = icsk->icsk_ext_hdr_len;
876 struct sockaddr_in sin;
877
878 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
879
880 if (__ipv6_only_sock(sk))
881 return -ENETUNREACH;
882
883 sin.sin_family = AF_INET;
884 sin.sin_port = usin->sin6_port;
885 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
886
887 icsk->icsk_af_ops = &dccp_ipv6_mapped;
888 sk->sk_backlog_rcv = dccp_v4_do_rcv;
889
890 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
891 if (err) {
892 icsk->icsk_ext_hdr_len = exthdrlen;
893 icsk->icsk_af_ops = &dccp_ipv6_af_ops;
894 sk->sk_backlog_rcv = dccp_v6_do_rcv;
895 goto failure;
896 }
897 np->saddr = sk->sk_v6_rcv_saddr;
898 return err;
899 }
900
901 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
902 saddr = &sk->sk_v6_rcv_saddr;
903
904 fl6.flowi6_proto = IPPROTO_DCCP;
905 fl6.daddr = sk->sk_v6_daddr;
906 fl6.saddr = saddr ? *saddr : np->saddr;
907 fl6.flowi6_oif = sk->sk_bound_dev_if;
908 fl6.fl6_dport = usin->sin6_port;
909 fl6.fl6_sport = inet->inet_sport;
910 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
911
912 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
913 final_p = fl6_update_dst(&fl6, opt, &final);
914
915 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
916 if (IS_ERR(dst)) {
917 err = PTR_ERR(dst);
918 goto failure;
919 }
920
921 if (saddr == NULL) {
922 saddr = &fl6.saddr;
923 sk->sk_v6_rcv_saddr = *saddr;
924 }
925
926 /* set the source address */
927 np->saddr = *saddr;
928 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
929
930 ip6_dst_store(sk, dst, NULL, NULL);
931
932 icsk->icsk_ext_hdr_len = 0;
933 if (opt)
934 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
935
936 inet->inet_dport = usin->sin6_port;
937
938 dccp_set_state(sk, DCCP_REQUESTING);
939 err = inet6_hash_connect(&dccp_death_row, sk);
940 if (err)
941 goto late_failure;
942
943 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
944 sk->sk_v6_daddr.s6_addr32,
945 inet->inet_sport,
946 inet->inet_dport);
947 err = dccp_connect(sk);
948 if (err)
949 goto late_failure;
950
951 return 0;
952
953 late_failure:
954 dccp_set_state(sk, DCCP_CLOSED);
955 __sk_dst_reset(sk);
956 failure:
957 inet->inet_dport = 0;
958 sk->sk_route_caps = 0;
959 return err;
960 }
961
962 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
963 .queue_xmit = inet6_csk_xmit,
964 .send_check = dccp_v6_send_check,
965 .rebuild_header = inet6_sk_rebuild_header,
966 .conn_request = dccp_v6_conn_request,
967 .syn_recv_sock = dccp_v6_request_recv_sock,
968 .net_header_len = sizeof(struct ipv6hdr),
969 .setsockopt = ipv6_setsockopt,
970 .getsockopt = ipv6_getsockopt,
971 .addr2sockaddr = inet6_csk_addr2sockaddr,
972 .sockaddr_len = sizeof(struct sockaddr_in6),
973 #ifdef CONFIG_COMPAT
974 .compat_setsockopt = compat_ipv6_setsockopt,
975 .compat_getsockopt = compat_ipv6_getsockopt,
976 #endif
977 };
978
979 /*
980 * DCCP over IPv4 via INET6 API
981 */
982 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
983 .queue_xmit = ip_queue_xmit,
984 .send_check = dccp_v4_send_check,
985 .rebuild_header = inet_sk_rebuild_header,
986 .conn_request = dccp_v6_conn_request,
987 .syn_recv_sock = dccp_v6_request_recv_sock,
988 .net_header_len = sizeof(struct iphdr),
989 .setsockopt = ipv6_setsockopt,
990 .getsockopt = ipv6_getsockopt,
991 .addr2sockaddr = inet6_csk_addr2sockaddr,
992 .sockaddr_len = sizeof(struct sockaddr_in6),
993 #ifdef CONFIG_COMPAT
994 .compat_setsockopt = compat_ipv6_setsockopt,
995 .compat_getsockopt = compat_ipv6_getsockopt,
996 #endif
997 };
998
999 /* NOTE: A lot of things set to zero explicitly by call to
1000 * sk_alloc() so need not be done here.
1001 */
1002 static int dccp_v6_init_sock(struct sock *sk)
1003 {
1004 static __u8 dccp_v6_ctl_sock_initialized;
1005 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
1006
1007 if (err == 0) {
1008 if (unlikely(!dccp_v6_ctl_sock_initialized))
1009 dccp_v6_ctl_sock_initialized = 1;
1010 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
1011 }
1012
1013 return err;
1014 }
1015
1016 static void dccp_v6_destroy_sock(struct sock *sk)
1017 {
1018 dccp_destroy_sock(sk);
1019 inet6_destroy_sock(sk);
1020 }
1021
1022 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
1023 .twsk_obj_size = sizeof(struct dccp6_timewait_sock),
1024 };
1025
1026 static struct proto dccp_v6_prot = {
1027 .name = "DCCPv6",
1028 .owner = THIS_MODULE,
1029 .close = dccp_close,
1030 .connect = dccp_v6_connect,
1031 .disconnect = dccp_disconnect,
1032 .ioctl = dccp_ioctl,
1033 .init = dccp_v6_init_sock,
1034 .setsockopt = dccp_setsockopt,
1035 .getsockopt = dccp_getsockopt,
1036 .sendmsg = dccp_sendmsg,
1037 .recvmsg = dccp_recvmsg,
1038 .backlog_rcv = dccp_v6_do_rcv,
1039 .hash = inet6_hash,
1040 .unhash = inet_unhash,
1041 .accept = inet_csk_accept,
1042 .get_port = inet_csk_get_port,
1043 .shutdown = dccp_shutdown,
1044 .destroy = dccp_v6_destroy_sock,
1045 .orphan_count = &dccp_orphan_count,
1046 .max_header = MAX_DCCP_HEADER,
1047 .obj_size = sizeof(struct dccp6_sock),
1048 .slab_flags = SLAB_TYPESAFE_BY_RCU,
1049 .rsk_prot = &dccp6_request_sock_ops,
1050 .twsk_prot = &dccp6_timewait_sock_ops,
1051 .h.hashinfo = &dccp_hashinfo,
1052 #ifdef CONFIG_COMPAT
1053 .compat_setsockopt = compat_dccp_setsockopt,
1054 .compat_getsockopt = compat_dccp_getsockopt,
1055 #endif
1056 };
1057
1058 static const struct inet6_protocol dccp_v6_protocol = {
1059 .handler = dccp_v6_rcv,
1060 .err_handler = dccp_v6_err,
1061 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1062 };
1063
1064 static const struct proto_ops inet6_dccp_ops = {
1065 .family = PF_INET6,
1066 .owner = THIS_MODULE,
1067 .release = inet6_release,
1068 .bind = inet6_bind,
1069 .connect = inet_stream_connect,
1070 .socketpair = sock_no_socketpair,
1071 .accept = inet_accept,
1072 .getname = inet6_getname,
1073 .poll = dccp_poll,
1074 .ioctl = inet6_ioctl,
1075 .listen = inet_dccp_listen,
1076 .shutdown = inet_shutdown,
1077 .setsockopt = sock_common_setsockopt,
1078 .getsockopt = sock_common_getsockopt,
1079 .sendmsg = inet_sendmsg,
1080 .recvmsg = sock_common_recvmsg,
1081 .mmap = sock_no_mmap,
1082 .sendpage = sock_no_sendpage,
1083 #ifdef CONFIG_COMPAT
1084 .compat_setsockopt = compat_sock_common_setsockopt,
1085 .compat_getsockopt = compat_sock_common_getsockopt,
1086 #endif
1087 };
1088
1089 static struct inet_protosw dccp_v6_protosw = {
1090 .type = SOCK_DCCP,
1091 .protocol = IPPROTO_DCCP,
1092 .prot = &dccp_v6_prot,
1093 .ops = &inet6_dccp_ops,
1094 .flags = INET_PROTOSW_ICSK,
1095 };
1096
1097 static int __net_init dccp_v6_init_net(struct net *net)
1098 {
1099 if (dccp_hashinfo.bhash == NULL)
1100 return -ESOCKTNOSUPPORT;
1101
1102 return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1103 SOCK_DCCP, IPPROTO_DCCP, net);
1104 }
1105
1106 static void __net_exit dccp_v6_exit_net(struct net *net)
1107 {
1108 inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1109 }
1110
1111 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
1112 {
1113 inet_twsk_purge(&dccp_hashinfo, AF_INET6);
1114 }
1115
1116 static struct pernet_operations dccp_v6_ops = {
1117 .init = dccp_v6_init_net,
1118 .exit = dccp_v6_exit_net,
1119 .exit_batch = dccp_v6_exit_batch,
1120 };
1121
1122 static int __init dccp_v6_init(void)
1123 {
1124 int err = proto_register(&dccp_v6_prot, 1);
1125
1126 if (err)
1127 goto out;
1128
1129 inet6_register_protosw(&dccp_v6_protosw);
1130
1131 err = register_pernet_subsys(&dccp_v6_ops);
1132 if (err)
1133 goto out_destroy_ctl_sock;
1134
1135 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1136 if (err)
1137 goto out_unregister_proto;
1138
1139 out:
1140 return err;
1141 out_unregister_proto:
1142 unregister_pernet_subsys(&dccp_v6_ops);
1143 out_destroy_ctl_sock:
1144 inet6_unregister_protosw(&dccp_v6_protosw);
1145 proto_unregister(&dccp_v6_prot);
1146 goto out;
1147 }
1148
1149 static void __exit dccp_v6_exit(void)
1150 {
1151 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1152 unregister_pernet_subsys(&dccp_v6_ops);
1153 inet6_unregister_protosw(&dccp_v6_protosw);
1154 proto_unregister(&dccp_v6_prot);
1155 }
1156
1157 module_init(dccp_v6_init);
1158 module_exit(dccp_v6_exit);
1159
1160 /*
1161 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1162 * values directly, Also cover the case where the protocol is not specified,
1163 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1164 */
1165 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1166 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1167 MODULE_LICENSE("GPL");
1168 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1169 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");
Linux with added FPC-III support