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1/*
2 * net/dccp/ipv4.c
3 *
4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/dccp.h>
14#include <linux/icmp.h>
15#include <linux/slab.h>
16#include <linux/module.h>
17#include <linux/skbuff.h>
18#include <linux/random.h>
19
20#include <net/icmp.h>
21#include <net/inet_common.h>
22#include <net/inet_hashtables.h>
23#include <net/inet_sock.h>
24#include <net/protocol.h>
25#include <net/sock.h>
26#include <net/timewait_sock.h>
27#include <net/tcp_states.h>
28#include <net/xfrm.h>
29#include <net/secure_seq.h>
30
31#include "ackvec.h"
32#include "ccid.h"
33#include "dccp.h"
34#include "feat.h"
35
36/*
37 * The per-net dccp.v4_ctl_sk socket is used for responding to
38 * the Out-of-the-blue (OOTB) packets. A control sock will be created
39 * for this socket at the initialization time.
40 */
41
42int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
43{
44 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
45 struct inet_sock *inet = inet_sk(sk);
46 struct dccp_sock *dp = dccp_sk(sk);
47 __be16 orig_sport, orig_dport;
48 __be32 daddr, nexthop;
49 struct flowi4 *fl4;
50 struct rtable *rt;
51 int err;
52 struct ip_options_rcu *inet_opt;
53
54 dp->dccps_role = DCCP_ROLE_CLIENT;
55
56 if (addr_len < sizeof(struct sockaddr_in))
57 return -EINVAL;
58
59 if (usin->sin_family != AF_INET)
60 return -EAFNOSUPPORT;
61
62 nexthop = daddr = usin->sin_addr.s_addr;
63
64 inet_opt = rcu_dereference_protected(inet->inet_opt,
65 sock_owned_by_user(sk));
66 if (inet_opt != NULL && inet_opt->opt.srr) {
67 if (daddr == 0)
68 return -EINVAL;
69 nexthop = inet_opt->opt.faddr;
70 }
71
72 orig_sport = inet->inet_sport;
73 orig_dport = usin->sin_port;
74 fl4 = &inet->cork.fl.u.ip4;
75 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
76 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
77 IPPROTO_DCCP,
78 orig_sport, orig_dport, sk, true);
79 if (IS_ERR(rt))
80 return PTR_ERR(rt);
81
82 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
83 ip_rt_put(rt);
84 return -ENETUNREACH;
85 }
86
87 if (inet_opt == NULL || !inet_opt->opt.srr)
88 daddr = fl4->daddr;
89
90 if (inet->inet_saddr == 0)
91 inet->inet_saddr = fl4->saddr;
92 inet->inet_rcv_saddr = inet->inet_saddr;
93
94 inet->inet_dport = usin->sin_port;
95 inet->inet_daddr = daddr;
96
97 inet_csk(sk)->icsk_ext_hdr_len = 0;
98 if (inet_opt)
99 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
100 /*
101 * Socket identity is still unknown (sport may be zero).
102 * However we set state to DCCP_REQUESTING and not releasing socket
103 * lock select source port, enter ourselves into the hash tables and
104 * complete initialization after this.
105 */
106 dccp_set_state(sk, DCCP_REQUESTING);
107 err = inet_hash_connect(&dccp_death_row, sk);
108 if (err != 0)
109 goto failure;
110
111 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
112 inet->inet_sport, inet->inet_dport, sk);
113 if (IS_ERR(rt)) {
114 rt = NULL;
115 goto failure;
116 }
117 /* OK, now commit destination to socket. */
118 sk_setup_caps(sk, &rt->dst);
119
120 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
121 inet->inet_daddr,
122 inet->inet_sport,
123 inet->inet_dport);
124 inet->inet_id = dp->dccps_iss ^ jiffies;
125
126 err = dccp_connect(sk);
127 rt = NULL;
128 if (err != 0)
129 goto failure;
130out:
131 return err;
132failure:
133 /*
134 * This unhashes the socket and releases the local port, if necessary.
135 */
136 dccp_set_state(sk, DCCP_CLOSED);
137 ip_rt_put(rt);
138 sk->sk_route_caps = 0;
139 inet->inet_dport = 0;
140 goto out;
141}
142
143EXPORT_SYMBOL_GPL(dccp_v4_connect);
144
145/*
146 * This routine does path mtu discovery as defined in RFC1191.
147 */
148static inline void dccp_do_pmtu_discovery(struct sock *sk,
149 const struct iphdr *iph,
150 u32 mtu)
151{
152 struct dst_entry *dst;
153 const struct inet_sock *inet = inet_sk(sk);
154 const struct dccp_sock *dp = dccp_sk(sk);
155
156 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
157 * send out by Linux are always < 576bytes so they should go through
158 * unfragmented).
159 */
160 if (sk->sk_state == DCCP_LISTEN)
161 return;
162
163 /* We don't check in the destentry if pmtu discovery is forbidden
164 * on this route. We just assume that no packet_to_big packets
165 * are send back when pmtu discovery is not active.
166 * There is a small race when the user changes this flag in the
167 * route, but I think that's acceptable.
168 */
169 if ((dst = __sk_dst_check(sk, 0)) == NULL)
170 return;
171
172 dst->ops->update_pmtu(dst, mtu);
173
174 /* Something is about to be wrong... Remember soft error
175 * for the case, if this connection will not able to recover.
176 */
177 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
178 sk->sk_err_soft = EMSGSIZE;
179
180 mtu = dst_mtu(dst);
181
182 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
183 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
184 dccp_sync_mss(sk, mtu);
185
186 /*
187 * From RFC 4340, sec. 14.1:
188 *
189 * DCCP-Sync packets are the best choice for upward
190 * probing, since DCCP-Sync probes do not risk application
191 * data loss.
192 */
193 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
194 } /* else let the usual retransmit timer handle it */
195}
196
197/*
198 * This routine is called by the ICMP module when it gets some sort of error
199 * condition. If err < 0 then the socket should be closed and the error
200 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
201 * After adjustment header points to the first 8 bytes of the tcp header. We
202 * need to find the appropriate port.
203 *
204 * The locking strategy used here is very "optimistic". When someone else
205 * accesses the socket the ICMP is just dropped and for some paths there is no
206 * check at all. A more general error queue to queue errors for later handling
207 * is probably better.
208 */
209static void dccp_v4_err(struct sk_buff *skb, u32 info)
210{
211 const struct iphdr *iph = (struct iphdr *)skb->data;
212 const u8 offset = iph->ihl << 2;
213 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
214 struct dccp_sock *dp;
215 struct inet_sock *inet;
216 const int type = icmp_hdr(skb)->type;
217 const int code = icmp_hdr(skb)->code;
218 struct sock *sk;
219 __u64 seq;
220 int err;
221 struct net *net = dev_net(skb->dev);
222
223 if (skb->len < offset + sizeof(*dh) ||
224 skb->len < offset + __dccp_basic_hdr_len(dh)) {
225 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
226 return;
227 }
228
229 sk = inet_lookup(net, &dccp_hashinfo,
230 iph->daddr, dh->dccph_dport,
231 iph->saddr, dh->dccph_sport, inet_iif(skb));
232 if (sk == NULL) {
233 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
234 return;
235 }
236
237 if (sk->sk_state == DCCP_TIME_WAIT) {
238 inet_twsk_put(inet_twsk(sk));
239 return;
240 }
241
242 bh_lock_sock(sk);
243 /* If too many ICMPs get dropped on busy
244 * servers this needs to be solved differently.
245 */
246 if (sock_owned_by_user(sk))
247 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
248
249 if (sk->sk_state == DCCP_CLOSED)
250 goto out;
251
252 dp = dccp_sk(sk);
253 seq = dccp_hdr_seq(dh);
254 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
255 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
256 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
257 goto out;
258 }
259
260 switch (type) {
261 case ICMP_SOURCE_QUENCH:
262 /* Just silently ignore these. */
263 goto out;
264 case ICMP_PARAMETERPROB:
265 err = EPROTO;
266 break;
267 case ICMP_DEST_UNREACH:
268 if (code > NR_ICMP_UNREACH)
269 goto out;
270
271 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
272 if (!sock_owned_by_user(sk))
273 dccp_do_pmtu_discovery(sk, iph, info);
274 goto out;
275 }
276
277 err = icmp_err_convert[code].errno;
278 break;
279 case ICMP_TIME_EXCEEDED:
280 err = EHOSTUNREACH;
281 break;
282 default:
283 goto out;
284 }
285
286 switch (sk->sk_state) {
287 struct request_sock *req , **prev;
288 case DCCP_LISTEN:
289 if (sock_owned_by_user(sk))
290 goto out;
291 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
292 iph->daddr, iph->saddr);
293 if (!req)
294 goto out;
295
296 /*
297 * ICMPs are not backlogged, hence we cannot get an established
298 * socket here.
299 */
300 WARN_ON(req->sk);
301
302 if (seq != dccp_rsk(req)->dreq_iss) {
303 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
304 goto out;
305 }
306 /*
307 * Still in RESPOND, just remove it silently.
308 * There is no good way to pass the error to the newly
309 * created socket, and POSIX does not want network
310 * errors returned from accept().
311 */
312 inet_csk_reqsk_queue_drop(sk, req, prev);
313 goto out;
314
315 case DCCP_REQUESTING:
316 case DCCP_RESPOND:
317 if (!sock_owned_by_user(sk)) {
318 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
319 sk->sk_err = err;
320
321 sk->sk_error_report(sk);
322
323 dccp_done(sk);
324 } else
325 sk->sk_err_soft = err;
326 goto out;
327 }
328
329 /* If we've already connected we will keep trying
330 * until we time out, or the user gives up.
331 *
332 * rfc1122 4.2.3.9 allows to consider as hard errors
333 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
334 * but it is obsoleted by pmtu discovery).
335 *
336 * Note, that in modern internet, where routing is unreliable
337 * and in each dark corner broken firewalls sit, sending random
338 * errors ordered by their masters even this two messages finally lose
339 * their original sense (even Linux sends invalid PORT_UNREACHs)
340 *
341 * Now we are in compliance with RFCs.
342 * --ANK (980905)
343 */
344
345 inet = inet_sk(sk);
346 if (!sock_owned_by_user(sk) && inet->recverr) {
347 sk->sk_err = err;
348 sk->sk_error_report(sk);
349 } else /* Only an error on timeout */
350 sk->sk_err_soft = err;
351out:
352 bh_unlock_sock(sk);
353 sock_put(sk);
354}
355
356static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
357 __be32 src, __be32 dst)
358{
359 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
360}
361
362void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
363{
364 const struct inet_sock *inet = inet_sk(sk);
365 struct dccp_hdr *dh = dccp_hdr(skb);
366
367 dccp_csum_outgoing(skb);
368 dh->dccph_checksum = dccp_v4_csum_finish(skb,
369 inet->inet_saddr,
370 inet->inet_daddr);
371}
372
373EXPORT_SYMBOL_GPL(dccp_v4_send_check);
374
375static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
376{
377 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
378 ip_hdr(skb)->saddr,
379 dccp_hdr(skb)->dccph_dport,
380 dccp_hdr(skb)->dccph_sport);
381}
382
383/*
384 * The three way handshake has completed - we got a valid ACK or DATAACK -
385 * now create the new socket.
386 *
387 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
388 */
389struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
390 struct request_sock *req,
391 struct dst_entry *dst)
392{
393 struct inet_request_sock *ireq;
394 struct inet_sock *newinet;
395 struct sock *newsk;
396
397 if (sk_acceptq_is_full(sk))
398 goto exit_overflow;
399
400 newsk = dccp_create_openreq_child(sk, req, skb);
401 if (newsk == NULL)
402 goto exit_nonewsk;
403
404 newinet = inet_sk(newsk);
405 ireq = inet_rsk(req);
406 newinet->inet_daddr = ireq->rmt_addr;
407 newinet->inet_rcv_saddr = ireq->loc_addr;
408 newinet->inet_saddr = ireq->loc_addr;
409 newinet->inet_opt = ireq->opt;
410 ireq->opt = NULL;
411 newinet->mc_index = inet_iif(skb);
412 newinet->mc_ttl = ip_hdr(skb)->ttl;
413 newinet->inet_id = jiffies;
414
415 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
416 goto put_and_exit;
417
418 sk_setup_caps(newsk, dst);
419
420 dccp_sync_mss(newsk, dst_mtu(dst));
421
422 if (__inet_inherit_port(sk, newsk) < 0)
423 goto put_and_exit;
424 __inet_hash_nolisten(newsk, NULL);
425
426 return newsk;
427
428exit_overflow:
429 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
430exit_nonewsk:
431 dst_release(dst);
432exit:
433 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
434 return NULL;
435put_and_exit:
436 sock_put(newsk);
437 goto exit;
438}
439
440EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
441
442static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
443{
444 const struct dccp_hdr *dh = dccp_hdr(skb);
445 const struct iphdr *iph = ip_hdr(skb);
446 struct sock *nsk;
447 struct request_sock **prev;
448 /* Find possible connection requests. */
449 struct request_sock *req = inet_csk_search_req(sk, &prev,
450 dh->dccph_sport,
451 iph->saddr, iph->daddr);
452 if (req != NULL)
453 return dccp_check_req(sk, skb, req, prev);
454
455 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
456 iph->saddr, dh->dccph_sport,
457 iph->daddr, dh->dccph_dport,
458 inet_iif(skb));
459 if (nsk != NULL) {
460 if (nsk->sk_state != DCCP_TIME_WAIT) {
461 bh_lock_sock(nsk);
462 return nsk;
463 }
464 inet_twsk_put(inet_twsk(nsk));
465 return NULL;
466 }
467
468 return sk;
469}
470
471static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
472 struct sk_buff *skb)
473{
474 struct rtable *rt;
475 struct flowi4 fl4 = {
476 .flowi4_oif = skb_rtable(skb)->rt_iif,
477 .daddr = ip_hdr(skb)->saddr,
478 .saddr = ip_hdr(skb)->daddr,
479 .flowi4_tos = RT_CONN_FLAGS(sk),
480 .flowi4_proto = sk->sk_protocol,
481 .fl4_sport = dccp_hdr(skb)->dccph_dport,
482 .fl4_dport = dccp_hdr(skb)->dccph_sport,
483 };
484
485 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
486 rt = ip_route_output_flow(net, &fl4, sk);
487 if (IS_ERR(rt)) {
488 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
489 return NULL;
490 }
491
492 return &rt->dst;
493}
494
495static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
496 struct request_values *rv_unused)
497{
498 int err = -1;
499 struct sk_buff *skb;
500 struct dst_entry *dst;
501 struct flowi4 fl4;
502
503 dst = inet_csk_route_req(sk, &fl4, req);
504 if (dst == NULL)
505 goto out;
506
507 skb = dccp_make_response(sk, dst, req);
508 if (skb != NULL) {
509 const struct inet_request_sock *ireq = inet_rsk(req);
510 struct dccp_hdr *dh = dccp_hdr(skb);
511
512 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
513 ireq->rmt_addr);
514 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
515 ireq->rmt_addr,
516 ireq->opt);
517 err = net_xmit_eval(err);
518 }
519
520out:
521 dst_release(dst);
522 return err;
523}
524
525static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
526{
527 int err;
528 const struct iphdr *rxiph;
529 struct sk_buff *skb;
530 struct dst_entry *dst;
531 struct net *net = dev_net(skb_dst(rxskb)->dev);
532 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
533
534 /* Never send a reset in response to a reset. */
535 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
536 return;
537
538 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
539 return;
540
541 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
542 if (dst == NULL)
543 return;
544
545 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
546 if (skb == NULL)
547 goto out;
548
549 rxiph = ip_hdr(rxskb);
550 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
551 rxiph->daddr);
552 skb_dst_set(skb, dst_clone(dst));
553
554 bh_lock_sock(ctl_sk);
555 err = ip_build_and_send_pkt(skb, ctl_sk,
556 rxiph->daddr, rxiph->saddr, NULL);
557 bh_unlock_sock(ctl_sk);
558
559 if (net_xmit_eval(err) == 0) {
560 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
561 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
562 }
563out:
564 dst_release(dst);
565}
566
567static void dccp_v4_reqsk_destructor(struct request_sock *req)
568{
569 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
570 kfree(inet_rsk(req)->opt);
571}
572
573static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
574 .family = PF_INET,
575 .obj_size = sizeof(struct dccp_request_sock),
576 .rtx_syn_ack = dccp_v4_send_response,
577 .send_ack = dccp_reqsk_send_ack,
578 .destructor = dccp_v4_reqsk_destructor,
579 .send_reset = dccp_v4_ctl_send_reset,
580};
581
582int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
583{
584 struct inet_request_sock *ireq;
585 struct request_sock *req;
586 struct dccp_request_sock *dreq;
587 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
588 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
589
590 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
591 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
592 return 0; /* discard, don't send a reset here */
593
594 if (dccp_bad_service_code(sk, service)) {
595 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
596 goto drop;
597 }
598 /*
599 * TW buckets are converted to open requests without
600 * limitations, they conserve resources and peer is
601 * evidently real one.
602 */
603 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
604 if (inet_csk_reqsk_queue_is_full(sk))
605 goto drop;
606
607 /*
608 * Accept backlog is full. If we have already queued enough
609 * of warm entries in syn queue, drop request. It is better than
610 * clogging syn queue with openreqs with exponentially increasing
611 * timeout.
612 */
613 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
614 goto drop;
615
616 req = inet_reqsk_alloc(&dccp_request_sock_ops);
617 if (req == NULL)
618 goto drop;
619
620 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
621 goto drop_and_free;
622
623 dreq = dccp_rsk(req);
624 if (dccp_parse_options(sk, dreq, skb))
625 goto drop_and_free;
626
627 if (security_inet_conn_request(sk, skb, req))
628 goto drop_and_free;
629
630 ireq = inet_rsk(req);
631 ireq->loc_addr = ip_hdr(skb)->daddr;
632 ireq->rmt_addr = ip_hdr(skb)->saddr;
633
634 /*
635 * Step 3: Process LISTEN state
636 *
637 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
638 *
639 * In fact we defer setting S.GSR, S.SWL, S.SWH to
640 * dccp_create_openreq_child.
641 */
642 dreq->dreq_isr = dcb->dccpd_seq;
643 dreq->dreq_iss = dccp_v4_init_sequence(skb);
644 dreq->dreq_service = service;
645
646 if (dccp_v4_send_response(sk, req, NULL))
647 goto drop_and_free;
648
649 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
650 return 0;
651
652drop_and_free:
653 reqsk_free(req);
654drop:
655 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
656 return -1;
657}
658
659EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
660
661int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
662{
663 struct dccp_hdr *dh = dccp_hdr(skb);
664
665 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
666 if (dccp_rcv_established(sk, skb, dh, skb->len))
667 goto reset;
668 return 0;
669 }
670
671 /*
672 * Step 3: Process LISTEN state
673 * If P.type == Request or P contains a valid Init Cookie option,
674 * (* Must scan the packet's options to check for Init
675 * Cookies. Only Init Cookies are processed here,
676 * however; other options are processed in Step 8. This
677 * scan need only be performed if the endpoint uses Init
678 * Cookies *)
679 * (* Generate a new socket and switch to that socket *)
680 * Set S := new socket for this port pair
681 * S.state = RESPOND
682 * Choose S.ISS (initial seqno) or set from Init Cookies
683 * Initialize S.GAR := S.ISS
684 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
685 * Continue with S.state == RESPOND
686 * (* A Response packet will be generated in Step 11 *)
687 * Otherwise,
688 * Generate Reset(No Connection) unless P.type == Reset
689 * Drop packet and return
690 *
691 * NOTE: the check for the packet types is done in
692 * dccp_rcv_state_process
693 */
694 if (sk->sk_state == DCCP_LISTEN) {
695 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
696
697 if (nsk == NULL)
698 goto discard;
699
700 if (nsk != sk) {
701 if (dccp_child_process(sk, nsk, skb))
702 goto reset;
703 return 0;
704 }
705 }
706
707 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
708 goto reset;
709 return 0;
710
711reset:
712 dccp_v4_ctl_send_reset(sk, skb);
713discard:
714 kfree_skb(skb);
715 return 0;
716}
717
718EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
719
720/**
721 * dccp_invalid_packet - check for malformed packets
722 * Implements RFC 4340, 8.5: Step 1: Check header basics
723 * Packets that fail these checks are ignored and do not receive Resets.
724 */
725int dccp_invalid_packet(struct sk_buff *skb)
726{
727 const struct dccp_hdr *dh;
728 unsigned int cscov;
729
730 if (skb->pkt_type != PACKET_HOST)
731 return 1;
732
733 /* If the packet is shorter than 12 bytes, drop packet and return */
734 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
735 DCCP_WARN("pskb_may_pull failed\n");
736 return 1;
737 }
738
739 dh = dccp_hdr(skb);
740
741 /* If P.type is not understood, drop packet and return */
742 if (dh->dccph_type >= DCCP_PKT_INVALID) {
743 DCCP_WARN("invalid packet type\n");
744 return 1;
745 }
746
747 /*
748 * If P.Data Offset is too small for packet type, drop packet and return
749 */
750 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
751 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
752 return 1;
753 }
754 /*
755 * If P.Data Offset is too too large for packet, drop packet and return
756 */
757 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
758 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
759 return 1;
760 }
761
762 /*
763 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
764 * has short sequence numbers), drop packet and return
765 */
766 if ((dh->dccph_type < DCCP_PKT_DATA ||
767 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
768 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
769 dccp_packet_name(dh->dccph_type));
770 return 1;
771 }
772
773 /*
774 * If P.CsCov is too large for the packet size, drop packet and return.
775 * This must come _before_ checksumming (not as RFC 4340 suggests).
776 */
777 cscov = dccp_csum_coverage(skb);
778 if (cscov > skb->len) {
779 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
780 dh->dccph_cscov, skb->len);
781 return 1;
782 }
783
784 /* If header checksum is incorrect, drop packet and return.
785 * (This step is completed in the AF-dependent functions.) */
786 skb->csum = skb_checksum(skb, 0, cscov, 0);
787
788 return 0;
789}
790
791EXPORT_SYMBOL_GPL(dccp_invalid_packet);
792
793/* this is called when real data arrives */
794static int dccp_v4_rcv(struct sk_buff *skb)
795{
796 const struct dccp_hdr *dh;
797 const struct iphdr *iph;
798 struct sock *sk;
799 int min_cov;
800
801 /* Step 1: Check header basics */
802
803 if (dccp_invalid_packet(skb))
804 goto discard_it;
805
806 iph = ip_hdr(skb);
807 /* Step 1: If header checksum is incorrect, drop packet and return */
808 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
809 DCCP_WARN("dropped packet with invalid checksum\n");
810 goto discard_it;
811 }
812
813 dh = dccp_hdr(skb);
814
815 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
816 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
817
818 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
819 dccp_packet_name(dh->dccph_type),
820 &iph->saddr, ntohs(dh->dccph_sport),
821 &iph->daddr, ntohs(dh->dccph_dport),
822 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
823
824 if (dccp_packet_without_ack(skb)) {
825 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
826 dccp_pr_debug_cat("\n");
827 } else {
828 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
829 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
830 DCCP_SKB_CB(skb)->dccpd_ack_seq);
831 }
832
833 /* Step 2:
834 * Look up flow ID in table and get corresponding socket */
835 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
836 dh->dccph_sport, dh->dccph_dport);
837 /*
838 * Step 2:
839 * If no socket ...
840 */
841 if (sk == NULL) {
842 dccp_pr_debug("failed to look up flow ID in table and "
843 "get corresponding socket\n");
844 goto no_dccp_socket;
845 }
846
847 /*
848 * Step 2:
849 * ... or S.state == TIMEWAIT,
850 * Generate Reset(No Connection) unless P.type == Reset
851 * Drop packet and return
852 */
853 if (sk->sk_state == DCCP_TIME_WAIT) {
854 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
855 inet_twsk_put(inet_twsk(sk));
856 goto no_dccp_socket;
857 }
858
859 /*
860 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
861 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
862 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
863 */
864 min_cov = dccp_sk(sk)->dccps_pcrlen;
865 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
866 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
867 dh->dccph_cscov, min_cov);
868 /* FIXME: "Such packets SHOULD be reported using Data Dropped
869 * options (Section 11.7) with Drop Code 0, Protocol
870 * Constraints." */
871 goto discard_and_relse;
872 }
873
874 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
875 goto discard_and_relse;
876 nf_reset(skb);
877
878 return sk_receive_skb(sk, skb, 1);
879
880no_dccp_socket:
881 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
882 goto discard_it;
883 /*
884 * Step 2:
885 * If no socket ...
886 * Generate Reset(No Connection) unless P.type == Reset
887 * Drop packet and return
888 */
889 if (dh->dccph_type != DCCP_PKT_RESET) {
890 DCCP_SKB_CB(skb)->dccpd_reset_code =
891 DCCP_RESET_CODE_NO_CONNECTION;
892 dccp_v4_ctl_send_reset(sk, skb);
893 }
894
895discard_it:
896 kfree_skb(skb);
897 return 0;
898
899discard_and_relse:
900 sock_put(sk);
901 goto discard_it;
902}
903
904static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
905 .queue_xmit = ip_queue_xmit,
906 .send_check = dccp_v4_send_check,
907 .rebuild_header = inet_sk_rebuild_header,
908 .conn_request = dccp_v4_conn_request,
909 .syn_recv_sock = dccp_v4_request_recv_sock,
910 .net_header_len = sizeof(struct iphdr),
911 .setsockopt = ip_setsockopt,
912 .getsockopt = ip_getsockopt,
913 .addr2sockaddr = inet_csk_addr2sockaddr,
914 .sockaddr_len = sizeof(struct sockaddr_in),
915 .bind_conflict = inet_csk_bind_conflict,
916#ifdef CONFIG_COMPAT
917 .compat_setsockopt = compat_ip_setsockopt,
918 .compat_getsockopt = compat_ip_getsockopt,
919#endif
920};
921
922static int dccp_v4_init_sock(struct sock *sk)
923{
924 static __u8 dccp_v4_ctl_sock_initialized;
925 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
926
927 if (err == 0) {
928 if (unlikely(!dccp_v4_ctl_sock_initialized))
929 dccp_v4_ctl_sock_initialized = 1;
930 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
931 }
932
933 return err;
934}
935
936static struct timewait_sock_ops dccp_timewait_sock_ops = {
937 .twsk_obj_size = sizeof(struct inet_timewait_sock),
938};
939
940static struct proto dccp_v4_prot = {
941 .name = "DCCP",
942 .owner = THIS_MODULE,
943 .close = dccp_close,
944 .connect = dccp_v4_connect,
945 .disconnect = dccp_disconnect,
946 .ioctl = dccp_ioctl,
947 .init = dccp_v4_init_sock,
948 .setsockopt = dccp_setsockopt,
949 .getsockopt = dccp_getsockopt,
950 .sendmsg = dccp_sendmsg,
951 .recvmsg = dccp_recvmsg,
952 .backlog_rcv = dccp_v4_do_rcv,
953 .hash = inet_hash,
954 .unhash = inet_unhash,
955 .accept = inet_csk_accept,
956 .get_port = inet_csk_get_port,
957 .shutdown = dccp_shutdown,
958 .destroy = dccp_destroy_sock,
959 .orphan_count = &dccp_orphan_count,
960 .max_header = MAX_DCCP_HEADER,
961 .obj_size = sizeof(struct dccp_sock),
962 .slab_flags = SLAB_DESTROY_BY_RCU,
963 .rsk_prot = &dccp_request_sock_ops,
964 .twsk_prot = &dccp_timewait_sock_ops,
965 .h.hashinfo = &dccp_hashinfo,
966#ifdef CONFIG_COMPAT
967 .compat_setsockopt = compat_dccp_setsockopt,
968 .compat_getsockopt = compat_dccp_getsockopt,
969#endif
970};
971
972static const struct net_protocol dccp_v4_protocol = {
973 .handler = dccp_v4_rcv,
974 .err_handler = dccp_v4_err,
975 .no_policy = 1,
976 .netns_ok = 1,
977};
978
979static const struct proto_ops inet_dccp_ops = {
980 .family = PF_INET,
981 .owner = THIS_MODULE,
982 .release = inet_release,
983 .bind = inet_bind,
984 .connect = inet_stream_connect,
985 .socketpair = sock_no_socketpair,
986 .accept = inet_accept,
987 .getname = inet_getname,
988 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
989 .poll = dccp_poll,
990 .ioctl = inet_ioctl,
991 /* FIXME: work on inet_listen to rename it to sock_common_listen */
992 .listen = inet_dccp_listen,
993 .shutdown = inet_shutdown,
994 .setsockopt = sock_common_setsockopt,
995 .getsockopt = sock_common_getsockopt,
996 .sendmsg = inet_sendmsg,
997 .recvmsg = sock_common_recvmsg,
998 .mmap = sock_no_mmap,
999 .sendpage = sock_no_sendpage,
1000#ifdef CONFIG_COMPAT
1001 .compat_setsockopt = compat_sock_common_setsockopt,
1002 .compat_getsockopt = compat_sock_common_getsockopt,
1003#endif
1004};
1005
1006static struct inet_protosw dccp_v4_protosw = {
1007 .type = SOCK_DCCP,
1008 .protocol = IPPROTO_DCCP,
1009 .prot = &dccp_v4_prot,
1010 .ops = &inet_dccp_ops,
1011 .no_check = 0,
1012 .flags = INET_PROTOSW_ICSK,
1013};
1014
1015static int __net_init dccp_v4_init_net(struct net *net)
1016{
1017 if (dccp_hashinfo.bhash == NULL)
1018 return -ESOCKTNOSUPPORT;
1019
1020 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1021 SOCK_DCCP, IPPROTO_DCCP, net);
1022}
1023
1024static void __net_exit dccp_v4_exit_net(struct net *net)
1025{
1026 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1027}
1028
1029static struct pernet_operations dccp_v4_ops = {
1030 .init = dccp_v4_init_net,
1031 .exit = dccp_v4_exit_net,
1032};
1033
1034static int __init dccp_v4_init(void)
1035{
1036 int err = proto_register(&dccp_v4_prot, 1);
1037
1038 if (err != 0)
1039 goto out;
1040
1041 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1042 if (err != 0)
1043 goto out_proto_unregister;
1044
1045 inet_register_protosw(&dccp_v4_protosw);
1046
1047 err = register_pernet_subsys(&dccp_v4_ops);
1048 if (err)
1049 goto out_destroy_ctl_sock;
1050out:
1051 return err;
1052out_destroy_ctl_sock:
1053 inet_unregister_protosw(&dccp_v4_protosw);
1054 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1055out_proto_unregister:
1056 proto_unregister(&dccp_v4_prot);
1057 goto out;
1058}
1059
1060static void __exit dccp_v4_exit(void)
1061{
1062 unregister_pernet_subsys(&dccp_v4_ops);
1063 inet_unregister_protosw(&dccp_v4_protosw);
1064 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1065 proto_unregister(&dccp_v4_prot);
1066}
1067
1068module_init(dccp_v4_init);
1069module_exit(dccp_v4_exit);
1070
1071/*
1072 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1073 * values directly, Also cover the case where the protocol is not specified,
1074 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1075 */
1076MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1077MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1078MODULE_LICENSE("GPL");
1079MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1080MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/dccp/ipv4.c
4 *
5 * An implementation of the DCCP protocol
6 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7 */
8
9#include <linux/dccp.h>
10#include <linux/icmp.h>
11#include <linux/slab.h>
12#include <linux/module.h>
13#include <linux/skbuff.h>
14#include <linux/random.h>
15
16#include <net/icmp.h>
17#include <net/inet_common.h>
18#include <net/inet_hashtables.h>
19#include <net/inet_sock.h>
20#include <net/protocol.h>
21#include <net/sock.h>
22#include <net/timewait_sock.h>
23#include <net/tcp_states.h>
24#include <net/xfrm.h>
25#include <net/secure_seq.h>
26
27#include "ackvec.h"
28#include "ccid.h"
29#include "dccp.h"
30#include "feat.h"
31
32/*
33 * The per-net dccp.v4_ctl_sk socket is used for responding to
34 * the Out-of-the-blue (OOTB) packets. A control sock will be created
35 * for this socket at the initialization time.
36 */
37
38int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
39{
40 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
41 struct inet_sock *inet = inet_sk(sk);
42 struct dccp_sock *dp = dccp_sk(sk);
43 __be16 orig_sport, orig_dport;
44 __be32 daddr, nexthop;
45 struct flowi4 *fl4;
46 struct rtable *rt;
47 int err;
48 struct ip_options_rcu *inet_opt;
49
50 dp->dccps_role = DCCP_ROLE_CLIENT;
51
52 if (addr_len < sizeof(struct sockaddr_in))
53 return -EINVAL;
54
55 if (usin->sin_family != AF_INET)
56 return -EAFNOSUPPORT;
57
58 nexthop = daddr = usin->sin_addr.s_addr;
59
60 inet_opt = rcu_dereference_protected(inet->inet_opt,
61 lockdep_sock_is_held(sk));
62 if (inet_opt != NULL && inet_opt->opt.srr) {
63 if (daddr == 0)
64 return -EINVAL;
65 nexthop = inet_opt->opt.faddr;
66 }
67
68 orig_sport = inet->inet_sport;
69 orig_dport = usin->sin_port;
70 fl4 = &inet->cork.fl.u.ip4;
71 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
72 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
73 IPPROTO_DCCP,
74 orig_sport, orig_dport, sk);
75 if (IS_ERR(rt))
76 return PTR_ERR(rt);
77
78 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
79 ip_rt_put(rt);
80 return -ENETUNREACH;
81 }
82
83 if (inet_opt == NULL || !inet_opt->opt.srr)
84 daddr = fl4->daddr;
85
86 if (inet->inet_saddr == 0)
87 inet->inet_saddr = fl4->saddr;
88 sk_rcv_saddr_set(sk, inet->inet_saddr);
89 inet->inet_dport = usin->sin_port;
90 sk_daddr_set(sk, daddr);
91
92 inet_csk(sk)->icsk_ext_hdr_len = 0;
93 if (inet_opt)
94 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
95 /*
96 * Socket identity is still unknown (sport may be zero).
97 * However we set state to DCCP_REQUESTING and not releasing socket
98 * lock select source port, enter ourselves into the hash tables and
99 * complete initialization after this.
100 */
101 dccp_set_state(sk, DCCP_REQUESTING);
102 err = inet_hash_connect(&dccp_death_row, sk);
103 if (err != 0)
104 goto failure;
105
106 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
107 inet->inet_sport, inet->inet_dport, sk);
108 if (IS_ERR(rt)) {
109 err = PTR_ERR(rt);
110 rt = NULL;
111 goto failure;
112 }
113 /* OK, now commit destination to socket. */
114 sk_setup_caps(sk, &rt->dst);
115
116 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
117 inet->inet_daddr,
118 inet->inet_sport,
119 inet->inet_dport);
120 inet->inet_id = prandom_u32();
121
122 err = dccp_connect(sk);
123 rt = NULL;
124 if (err != 0)
125 goto failure;
126out:
127 return err;
128failure:
129 /*
130 * This unhashes the socket and releases the local port, if necessary.
131 */
132 dccp_set_state(sk, DCCP_CLOSED);
133 ip_rt_put(rt);
134 sk->sk_route_caps = 0;
135 inet->inet_dport = 0;
136 goto out;
137}
138EXPORT_SYMBOL_GPL(dccp_v4_connect);
139
140/*
141 * This routine does path mtu discovery as defined in RFC1191.
142 */
143static inline void dccp_do_pmtu_discovery(struct sock *sk,
144 const struct iphdr *iph,
145 u32 mtu)
146{
147 struct dst_entry *dst;
148 const struct inet_sock *inet = inet_sk(sk);
149 const struct dccp_sock *dp = dccp_sk(sk);
150
151 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
152 * send out by Linux are always < 576bytes so they should go through
153 * unfragmented).
154 */
155 if (sk->sk_state == DCCP_LISTEN)
156 return;
157
158 dst = inet_csk_update_pmtu(sk, mtu);
159 if (!dst)
160 return;
161
162 /* Something is about to be wrong... Remember soft error
163 * for the case, if this connection will not able to recover.
164 */
165 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
166 sk->sk_err_soft = EMSGSIZE;
167
168 mtu = dst_mtu(dst);
169
170 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
171 ip_sk_accept_pmtu(sk) &&
172 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
173 dccp_sync_mss(sk, mtu);
174
175 /*
176 * From RFC 4340, sec. 14.1:
177 *
178 * DCCP-Sync packets are the best choice for upward
179 * probing, since DCCP-Sync probes do not risk application
180 * data loss.
181 */
182 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
183 } /* else let the usual retransmit timer handle it */
184}
185
186static void dccp_do_redirect(struct sk_buff *skb, struct sock *sk)
187{
188 struct dst_entry *dst = __sk_dst_check(sk, 0);
189
190 if (dst)
191 dst->ops->redirect(dst, sk, skb);
192}
193
194void dccp_req_err(struct sock *sk, u64 seq)
195 {
196 struct request_sock *req = inet_reqsk(sk);
197 struct net *net = sock_net(sk);
198
199 /*
200 * ICMPs are not backlogged, hence we cannot get an established
201 * socket here.
202 */
203 if (!between48(seq, dccp_rsk(req)->dreq_iss, dccp_rsk(req)->dreq_gss)) {
204 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
205 } else {
206 /*
207 * Still in RESPOND, just remove it silently.
208 * There is no good way to pass the error to the newly
209 * created socket, and POSIX does not want network
210 * errors returned from accept().
211 */
212 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
213 }
214 reqsk_put(req);
215}
216EXPORT_SYMBOL(dccp_req_err);
217
218/*
219 * This routine is called by the ICMP module when it gets some sort of error
220 * condition. If err < 0 then the socket should be closed and the error
221 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
222 * After adjustment header points to the first 8 bytes of the tcp header. We
223 * need to find the appropriate port.
224 *
225 * The locking strategy used here is very "optimistic". When someone else
226 * accesses the socket the ICMP is just dropped and for some paths there is no
227 * check at all. A more general error queue to queue errors for later handling
228 * is probably better.
229 */
230static int dccp_v4_err(struct sk_buff *skb, u32 info)
231{
232 const struct iphdr *iph = (struct iphdr *)skb->data;
233 const u8 offset = iph->ihl << 2;
234 const struct dccp_hdr *dh;
235 struct dccp_sock *dp;
236 struct inet_sock *inet;
237 const int type = icmp_hdr(skb)->type;
238 const int code = icmp_hdr(skb)->code;
239 struct sock *sk;
240 __u64 seq;
241 int err;
242 struct net *net = dev_net(skb->dev);
243
244 /* Only need dccph_dport & dccph_sport which are the first
245 * 4 bytes in dccp header.
246 * Our caller (icmp_socket_deliver()) already pulled 8 bytes for us.
247 */
248 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
249 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
250 dh = (struct dccp_hdr *)(skb->data + offset);
251
252 sk = __inet_lookup_established(net, &dccp_hashinfo,
253 iph->daddr, dh->dccph_dport,
254 iph->saddr, ntohs(dh->dccph_sport),
255 inet_iif(skb), 0);
256 if (!sk) {
257 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
258 return -ENOENT;
259 }
260
261 if (sk->sk_state == DCCP_TIME_WAIT) {
262 inet_twsk_put(inet_twsk(sk));
263 return 0;
264 }
265 seq = dccp_hdr_seq(dh);
266 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
267 dccp_req_err(sk, seq);
268 return 0;
269 }
270
271 bh_lock_sock(sk);
272 /* If too many ICMPs get dropped on busy
273 * servers this needs to be solved differently.
274 */
275 if (sock_owned_by_user(sk))
276 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
277
278 if (sk->sk_state == DCCP_CLOSED)
279 goto out;
280
281 dp = dccp_sk(sk);
282 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
283 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
284 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
285 goto out;
286 }
287
288 switch (type) {
289 case ICMP_REDIRECT:
290 if (!sock_owned_by_user(sk))
291 dccp_do_redirect(skb, sk);
292 goto out;
293 case ICMP_SOURCE_QUENCH:
294 /* Just silently ignore these. */
295 goto out;
296 case ICMP_PARAMETERPROB:
297 err = EPROTO;
298 break;
299 case ICMP_DEST_UNREACH:
300 if (code > NR_ICMP_UNREACH)
301 goto out;
302
303 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
304 if (!sock_owned_by_user(sk))
305 dccp_do_pmtu_discovery(sk, iph, info);
306 goto out;
307 }
308
309 err = icmp_err_convert[code].errno;
310 break;
311 case ICMP_TIME_EXCEEDED:
312 err = EHOSTUNREACH;
313 break;
314 default:
315 goto out;
316 }
317
318 switch (sk->sk_state) {
319 case DCCP_REQUESTING:
320 case DCCP_RESPOND:
321 if (!sock_owned_by_user(sk)) {
322 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
323 sk->sk_err = err;
324
325 sk->sk_error_report(sk);
326
327 dccp_done(sk);
328 } else
329 sk->sk_err_soft = err;
330 goto out;
331 }
332
333 /* If we've already connected we will keep trying
334 * until we time out, or the user gives up.
335 *
336 * rfc1122 4.2.3.9 allows to consider as hard errors
337 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
338 * but it is obsoleted by pmtu discovery).
339 *
340 * Note, that in modern internet, where routing is unreliable
341 * and in each dark corner broken firewalls sit, sending random
342 * errors ordered by their masters even this two messages finally lose
343 * their original sense (even Linux sends invalid PORT_UNREACHs)
344 *
345 * Now we are in compliance with RFCs.
346 * --ANK (980905)
347 */
348
349 inet = inet_sk(sk);
350 if (!sock_owned_by_user(sk) && inet->recverr) {
351 sk->sk_err = err;
352 sk->sk_error_report(sk);
353 } else /* Only an error on timeout */
354 sk->sk_err_soft = err;
355out:
356 bh_unlock_sock(sk);
357 sock_put(sk);
358 return 0;
359}
360
361static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
362 __be32 src, __be32 dst)
363{
364 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
365}
366
367void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
368{
369 const struct inet_sock *inet = inet_sk(sk);
370 struct dccp_hdr *dh = dccp_hdr(skb);
371
372 dccp_csum_outgoing(skb);
373 dh->dccph_checksum = dccp_v4_csum_finish(skb,
374 inet->inet_saddr,
375 inet->inet_daddr);
376}
377EXPORT_SYMBOL_GPL(dccp_v4_send_check);
378
379static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
380{
381 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
382 ip_hdr(skb)->saddr,
383 dccp_hdr(skb)->dccph_dport,
384 dccp_hdr(skb)->dccph_sport);
385}
386
387/*
388 * The three way handshake has completed - we got a valid ACK or DATAACK -
389 * now create the new socket.
390 *
391 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
392 */
393struct sock *dccp_v4_request_recv_sock(const struct sock *sk,
394 struct sk_buff *skb,
395 struct request_sock *req,
396 struct dst_entry *dst,
397 struct request_sock *req_unhash,
398 bool *own_req)
399{
400 struct inet_request_sock *ireq;
401 struct inet_sock *newinet;
402 struct sock *newsk;
403
404 if (sk_acceptq_is_full(sk))
405 goto exit_overflow;
406
407 newsk = dccp_create_openreq_child(sk, req, skb);
408 if (newsk == NULL)
409 goto exit_nonewsk;
410
411 newinet = inet_sk(newsk);
412 ireq = inet_rsk(req);
413 sk_daddr_set(newsk, ireq->ir_rmt_addr);
414 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
415 newinet->inet_saddr = ireq->ir_loc_addr;
416 RCU_INIT_POINTER(newinet->inet_opt, rcu_dereference(ireq->ireq_opt));
417 newinet->mc_index = inet_iif(skb);
418 newinet->mc_ttl = ip_hdr(skb)->ttl;
419 newinet->inet_id = prandom_u32();
420
421 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
422 goto put_and_exit;
423
424 sk_setup_caps(newsk, dst);
425
426 dccp_sync_mss(newsk, dst_mtu(dst));
427
428 if (__inet_inherit_port(sk, newsk) < 0)
429 goto put_and_exit;
430 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
431 if (*own_req)
432 ireq->ireq_opt = NULL;
433 else
434 newinet->inet_opt = NULL;
435 return newsk;
436
437exit_overflow:
438 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
439exit_nonewsk:
440 dst_release(dst);
441exit:
442 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
443 return NULL;
444put_and_exit:
445 newinet->inet_opt = NULL;
446 inet_csk_prepare_forced_close(newsk);
447 dccp_done(newsk);
448 goto exit;
449}
450EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
451
452static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
453 struct sk_buff *skb)
454{
455 struct rtable *rt;
456 const struct iphdr *iph = ip_hdr(skb);
457 struct flowi4 fl4 = {
458 .flowi4_oif = inet_iif(skb),
459 .daddr = iph->saddr,
460 .saddr = iph->daddr,
461 .flowi4_tos = RT_CONN_FLAGS(sk),
462 .flowi4_proto = sk->sk_protocol,
463 .fl4_sport = dccp_hdr(skb)->dccph_dport,
464 .fl4_dport = dccp_hdr(skb)->dccph_sport,
465 };
466
467 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
468 rt = ip_route_output_flow(net, &fl4, sk);
469 if (IS_ERR(rt)) {
470 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
471 return NULL;
472 }
473
474 return &rt->dst;
475}
476
477static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req)
478{
479 int err = -1;
480 struct sk_buff *skb;
481 struct dst_entry *dst;
482 struct flowi4 fl4;
483
484 dst = inet_csk_route_req(sk, &fl4, req);
485 if (dst == NULL)
486 goto out;
487
488 skb = dccp_make_response(sk, dst, req);
489 if (skb != NULL) {
490 const struct inet_request_sock *ireq = inet_rsk(req);
491 struct dccp_hdr *dh = dccp_hdr(skb);
492
493 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr,
494 ireq->ir_rmt_addr);
495 rcu_read_lock();
496 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
497 ireq->ir_rmt_addr,
498 rcu_dereference(ireq->ireq_opt));
499 rcu_read_unlock();
500 err = net_xmit_eval(err);
501 }
502
503out:
504 dst_release(dst);
505 return err;
506}
507
508static void dccp_v4_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
509{
510 int err;
511 const struct iphdr *rxiph;
512 struct sk_buff *skb;
513 struct dst_entry *dst;
514 struct net *net = dev_net(skb_dst(rxskb)->dev);
515 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
516
517 /* Never send a reset in response to a reset. */
518 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
519 return;
520
521 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
522 return;
523
524 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
525 if (dst == NULL)
526 return;
527
528 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
529 if (skb == NULL)
530 goto out;
531
532 rxiph = ip_hdr(rxskb);
533 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
534 rxiph->daddr);
535 skb_dst_set(skb, dst_clone(dst));
536
537 local_bh_disable();
538 bh_lock_sock(ctl_sk);
539 err = ip_build_and_send_pkt(skb, ctl_sk,
540 rxiph->daddr, rxiph->saddr, NULL);
541 bh_unlock_sock(ctl_sk);
542
543 if (net_xmit_eval(err) == 0) {
544 __DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
545 __DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
546 }
547 local_bh_enable();
548out:
549 dst_release(dst);
550}
551
552static void dccp_v4_reqsk_destructor(struct request_sock *req)
553{
554 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
555 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
556}
557
558void dccp_syn_ack_timeout(const struct request_sock *req)
559{
560}
561EXPORT_SYMBOL(dccp_syn_ack_timeout);
562
563static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
564 .family = PF_INET,
565 .obj_size = sizeof(struct dccp_request_sock),
566 .rtx_syn_ack = dccp_v4_send_response,
567 .send_ack = dccp_reqsk_send_ack,
568 .destructor = dccp_v4_reqsk_destructor,
569 .send_reset = dccp_v4_ctl_send_reset,
570 .syn_ack_timeout = dccp_syn_ack_timeout,
571};
572
573int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
574{
575 struct inet_request_sock *ireq;
576 struct request_sock *req;
577 struct dccp_request_sock *dreq;
578 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
579 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
580
581 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
582 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
583 return 0; /* discard, don't send a reset here */
584
585 if (dccp_bad_service_code(sk, service)) {
586 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
587 goto drop;
588 }
589 /*
590 * TW buckets are converted to open requests without
591 * limitations, they conserve resources and peer is
592 * evidently real one.
593 */
594 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
595 if (inet_csk_reqsk_queue_is_full(sk))
596 goto drop;
597
598 if (sk_acceptq_is_full(sk))
599 goto drop;
600
601 req = inet_reqsk_alloc(&dccp_request_sock_ops, sk, true);
602 if (req == NULL)
603 goto drop;
604
605 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
606 goto drop_and_free;
607
608 dreq = dccp_rsk(req);
609 if (dccp_parse_options(sk, dreq, skb))
610 goto drop_and_free;
611
612 if (security_inet_conn_request(sk, skb, req))
613 goto drop_and_free;
614
615 ireq = inet_rsk(req);
616 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
617 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
618 ireq->ir_mark = inet_request_mark(sk, skb);
619 ireq->ireq_family = AF_INET;
620 ireq->ir_iif = sk->sk_bound_dev_if;
621
622 /*
623 * Step 3: Process LISTEN state
624 *
625 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
626 *
627 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
628 */
629 dreq->dreq_isr = dcb->dccpd_seq;
630 dreq->dreq_gsr = dreq->dreq_isr;
631 dreq->dreq_iss = dccp_v4_init_sequence(skb);
632 dreq->dreq_gss = dreq->dreq_iss;
633 dreq->dreq_service = service;
634
635 if (dccp_v4_send_response(sk, req))
636 goto drop_and_free;
637
638 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
639 reqsk_put(req);
640 return 0;
641
642drop_and_free:
643 reqsk_free(req);
644drop:
645 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
646 return -1;
647}
648EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
649
650int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
651{
652 struct dccp_hdr *dh = dccp_hdr(skb);
653
654 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
655 if (dccp_rcv_established(sk, skb, dh, skb->len))
656 goto reset;
657 return 0;
658 }
659
660 /*
661 * Step 3: Process LISTEN state
662 * If P.type == Request or P contains a valid Init Cookie option,
663 * (* Must scan the packet's options to check for Init
664 * Cookies. Only Init Cookies are processed here,
665 * however; other options are processed in Step 8. This
666 * scan need only be performed if the endpoint uses Init
667 * Cookies *)
668 * (* Generate a new socket and switch to that socket *)
669 * Set S := new socket for this port pair
670 * S.state = RESPOND
671 * Choose S.ISS (initial seqno) or set from Init Cookies
672 * Initialize S.GAR := S.ISS
673 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
674 * Continue with S.state == RESPOND
675 * (* A Response packet will be generated in Step 11 *)
676 * Otherwise,
677 * Generate Reset(No Connection) unless P.type == Reset
678 * Drop packet and return
679 *
680 * NOTE: the check for the packet types is done in
681 * dccp_rcv_state_process
682 */
683
684 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
685 goto reset;
686 return 0;
687
688reset:
689 dccp_v4_ctl_send_reset(sk, skb);
690 kfree_skb(skb);
691 return 0;
692}
693EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
694
695/**
696 * dccp_invalid_packet - check for malformed packets
697 * Implements RFC 4340, 8.5: Step 1: Check header basics
698 * Packets that fail these checks are ignored and do not receive Resets.
699 */
700int dccp_invalid_packet(struct sk_buff *skb)
701{
702 const struct dccp_hdr *dh;
703 unsigned int cscov;
704 u8 dccph_doff;
705
706 if (skb->pkt_type != PACKET_HOST)
707 return 1;
708
709 /* If the packet is shorter than 12 bytes, drop packet and return */
710 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
711 DCCP_WARN("pskb_may_pull failed\n");
712 return 1;
713 }
714
715 dh = dccp_hdr(skb);
716
717 /* If P.type is not understood, drop packet and return */
718 if (dh->dccph_type >= DCCP_PKT_INVALID) {
719 DCCP_WARN("invalid packet type\n");
720 return 1;
721 }
722
723 /*
724 * If P.Data Offset is too small for packet type, drop packet and return
725 */
726 dccph_doff = dh->dccph_doff;
727 if (dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
728 DCCP_WARN("P.Data Offset(%u) too small\n", dccph_doff);
729 return 1;
730 }
731 /*
732 * If P.Data Offset is too too large for packet, drop packet and return
733 */
734 if (!pskb_may_pull(skb, dccph_doff * sizeof(u32))) {
735 DCCP_WARN("P.Data Offset(%u) too large\n", dccph_doff);
736 return 1;
737 }
738 dh = dccp_hdr(skb);
739 /*
740 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
741 * has short sequence numbers), drop packet and return
742 */
743 if ((dh->dccph_type < DCCP_PKT_DATA ||
744 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
745 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
746 dccp_packet_name(dh->dccph_type));
747 return 1;
748 }
749
750 /*
751 * If P.CsCov is too large for the packet size, drop packet and return.
752 * This must come _before_ checksumming (not as RFC 4340 suggests).
753 */
754 cscov = dccp_csum_coverage(skb);
755 if (cscov > skb->len) {
756 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
757 dh->dccph_cscov, skb->len);
758 return 1;
759 }
760
761 /* If header checksum is incorrect, drop packet and return.
762 * (This step is completed in the AF-dependent functions.) */
763 skb->csum = skb_checksum(skb, 0, cscov, 0);
764
765 return 0;
766}
767EXPORT_SYMBOL_GPL(dccp_invalid_packet);
768
769/* this is called when real data arrives */
770static int dccp_v4_rcv(struct sk_buff *skb)
771{
772 const struct dccp_hdr *dh;
773 const struct iphdr *iph;
774 bool refcounted;
775 struct sock *sk;
776 int min_cov;
777
778 /* Step 1: Check header basics */
779
780 if (dccp_invalid_packet(skb))
781 goto discard_it;
782
783 iph = ip_hdr(skb);
784 /* Step 1: If header checksum is incorrect, drop packet and return */
785 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
786 DCCP_WARN("dropped packet with invalid checksum\n");
787 goto discard_it;
788 }
789
790 dh = dccp_hdr(skb);
791
792 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
793 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
794
795 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
796 dccp_packet_name(dh->dccph_type),
797 &iph->saddr, ntohs(dh->dccph_sport),
798 &iph->daddr, ntohs(dh->dccph_dport),
799 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
800
801 if (dccp_packet_without_ack(skb)) {
802 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
803 dccp_pr_debug_cat("\n");
804 } else {
805 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
806 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
807 DCCP_SKB_CB(skb)->dccpd_ack_seq);
808 }
809
810lookup:
811 sk = __inet_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
812 dh->dccph_sport, dh->dccph_dport, 0, &refcounted);
813 if (!sk) {
814 dccp_pr_debug("failed to look up flow ID in table and "
815 "get corresponding socket\n");
816 goto no_dccp_socket;
817 }
818
819 /*
820 * Step 2:
821 * ... or S.state == TIMEWAIT,
822 * Generate Reset(No Connection) unless P.type == Reset
823 * Drop packet and return
824 */
825 if (sk->sk_state == DCCP_TIME_WAIT) {
826 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
827 inet_twsk_put(inet_twsk(sk));
828 goto no_dccp_socket;
829 }
830
831 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
832 struct request_sock *req = inet_reqsk(sk);
833 struct sock *nsk;
834
835 sk = req->rsk_listener;
836 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
837 inet_csk_reqsk_queue_drop_and_put(sk, req);
838 goto lookup;
839 }
840 sock_hold(sk);
841 refcounted = true;
842 nsk = dccp_check_req(sk, skb, req);
843 if (!nsk) {
844 reqsk_put(req);
845 goto discard_and_relse;
846 }
847 if (nsk == sk) {
848 reqsk_put(req);
849 } else if (dccp_child_process(sk, nsk, skb)) {
850 dccp_v4_ctl_send_reset(sk, skb);
851 goto discard_and_relse;
852 } else {
853 sock_put(sk);
854 return 0;
855 }
856 }
857 /*
858 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
859 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
860 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
861 */
862 min_cov = dccp_sk(sk)->dccps_pcrlen;
863 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
864 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
865 dh->dccph_cscov, min_cov);
866 /* FIXME: "Such packets SHOULD be reported using Data Dropped
867 * options (Section 11.7) with Drop Code 0, Protocol
868 * Constraints." */
869 goto discard_and_relse;
870 }
871
872 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
873 goto discard_and_relse;
874 nf_reset_ct(skb);
875
876 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, refcounted);
877
878no_dccp_socket:
879 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
880 goto discard_it;
881 /*
882 * Step 2:
883 * If no socket ...
884 * Generate Reset(No Connection) unless P.type == Reset
885 * Drop packet and return
886 */
887 if (dh->dccph_type != DCCP_PKT_RESET) {
888 DCCP_SKB_CB(skb)->dccpd_reset_code =
889 DCCP_RESET_CODE_NO_CONNECTION;
890 dccp_v4_ctl_send_reset(sk, skb);
891 }
892
893discard_it:
894 kfree_skb(skb);
895 return 0;
896
897discard_and_relse:
898 if (refcounted)
899 sock_put(sk);
900 goto discard_it;
901}
902
903static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
904 .queue_xmit = ip_queue_xmit,
905 .send_check = dccp_v4_send_check,
906 .rebuild_header = inet_sk_rebuild_header,
907 .conn_request = dccp_v4_conn_request,
908 .syn_recv_sock = dccp_v4_request_recv_sock,
909 .net_header_len = sizeof(struct iphdr),
910 .setsockopt = ip_setsockopt,
911 .getsockopt = ip_getsockopt,
912 .addr2sockaddr = inet_csk_addr2sockaddr,
913 .sockaddr_len = sizeof(struct sockaddr_in),
914#ifdef CONFIG_COMPAT
915 .compat_setsockopt = compat_ip_setsockopt,
916 .compat_getsockopt = compat_ip_getsockopt,
917#endif
918};
919
920static int dccp_v4_init_sock(struct sock *sk)
921{
922 static __u8 dccp_v4_ctl_sock_initialized;
923 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
924
925 if (err == 0) {
926 if (unlikely(!dccp_v4_ctl_sock_initialized))
927 dccp_v4_ctl_sock_initialized = 1;
928 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
929 }
930
931 return err;
932}
933
934static struct timewait_sock_ops dccp_timewait_sock_ops = {
935 .twsk_obj_size = sizeof(struct inet_timewait_sock),
936};
937
938static struct proto dccp_v4_prot = {
939 .name = "DCCP",
940 .owner = THIS_MODULE,
941 .close = dccp_close,
942 .connect = dccp_v4_connect,
943 .disconnect = dccp_disconnect,
944 .ioctl = dccp_ioctl,
945 .init = dccp_v4_init_sock,
946 .setsockopt = dccp_setsockopt,
947 .getsockopt = dccp_getsockopt,
948 .sendmsg = dccp_sendmsg,
949 .recvmsg = dccp_recvmsg,
950 .backlog_rcv = dccp_v4_do_rcv,
951 .hash = inet_hash,
952 .unhash = inet_unhash,
953 .accept = inet_csk_accept,
954 .get_port = inet_csk_get_port,
955 .shutdown = dccp_shutdown,
956 .destroy = dccp_destroy_sock,
957 .orphan_count = &dccp_orphan_count,
958 .max_header = MAX_DCCP_HEADER,
959 .obj_size = sizeof(struct dccp_sock),
960 .slab_flags = SLAB_TYPESAFE_BY_RCU,
961 .rsk_prot = &dccp_request_sock_ops,
962 .twsk_prot = &dccp_timewait_sock_ops,
963 .h.hashinfo = &dccp_hashinfo,
964#ifdef CONFIG_COMPAT
965 .compat_setsockopt = compat_dccp_setsockopt,
966 .compat_getsockopt = compat_dccp_getsockopt,
967#endif
968};
969
970static const struct net_protocol dccp_v4_protocol = {
971 .handler = dccp_v4_rcv,
972 .err_handler = dccp_v4_err,
973 .no_policy = 1,
974 .netns_ok = 1,
975 .icmp_strict_tag_validation = 1,
976};
977
978static const struct proto_ops inet_dccp_ops = {
979 .family = PF_INET,
980 .owner = THIS_MODULE,
981 .release = inet_release,
982 .bind = inet_bind,
983 .connect = inet_stream_connect,
984 .socketpair = sock_no_socketpair,
985 .accept = inet_accept,
986 .getname = inet_getname,
987 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
988 .poll = dccp_poll,
989 .ioctl = inet_ioctl,
990 .gettstamp = sock_gettstamp,
991 /* FIXME: work on inet_listen to rename it to sock_common_listen */
992 .listen = inet_dccp_listen,
993 .shutdown = inet_shutdown,
994 .setsockopt = sock_common_setsockopt,
995 .getsockopt = sock_common_getsockopt,
996 .sendmsg = inet_sendmsg,
997 .recvmsg = sock_common_recvmsg,
998 .mmap = sock_no_mmap,
999 .sendpage = sock_no_sendpage,
1000#ifdef CONFIG_COMPAT
1001 .compat_setsockopt = compat_sock_common_setsockopt,
1002 .compat_getsockopt = compat_sock_common_getsockopt,
1003#endif
1004};
1005
1006static struct inet_protosw dccp_v4_protosw = {
1007 .type = SOCK_DCCP,
1008 .protocol = IPPROTO_DCCP,
1009 .prot = &dccp_v4_prot,
1010 .ops = &inet_dccp_ops,
1011 .flags = INET_PROTOSW_ICSK,
1012};
1013
1014static int __net_init dccp_v4_init_net(struct net *net)
1015{
1016 if (dccp_hashinfo.bhash == NULL)
1017 return -ESOCKTNOSUPPORT;
1018
1019 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1020 SOCK_DCCP, IPPROTO_DCCP, net);
1021}
1022
1023static void __net_exit dccp_v4_exit_net(struct net *net)
1024{
1025 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1026}
1027
1028static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
1029{
1030 inet_twsk_purge(&dccp_hashinfo, AF_INET);
1031}
1032
1033static struct pernet_operations dccp_v4_ops = {
1034 .init = dccp_v4_init_net,
1035 .exit = dccp_v4_exit_net,
1036 .exit_batch = dccp_v4_exit_batch,
1037};
1038
1039static int __init dccp_v4_init(void)
1040{
1041 int err = proto_register(&dccp_v4_prot, 1);
1042
1043 if (err)
1044 goto out;
1045
1046 inet_register_protosw(&dccp_v4_protosw);
1047
1048 err = register_pernet_subsys(&dccp_v4_ops);
1049 if (err)
1050 goto out_destroy_ctl_sock;
1051
1052 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1053 if (err)
1054 goto out_proto_unregister;
1055
1056out:
1057 return err;
1058out_proto_unregister:
1059 unregister_pernet_subsys(&dccp_v4_ops);
1060out_destroy_ctl_sock:
1061 inet_unregister_protosw(&dccp_v4_protosw);
1062 proto_unregister(&dccp_v4_prot);
1063 goto out;
1064}
1065
1066static void __exit dccp_v4_exit(void)
1067{
1068 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1069 unregister_pernet_subsys(&dccp_v4_ops);
1070 inet_unregister_protosw(&dccp_v4_protosw);
1071 proto_unregister(&dccp_v4_prot);
1072}
1073
1074module_init(dccp_v4_init);
1075module_exit(dccp_v4_exit);
1076
1077/*
1078 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1079 * values directly, Also cover the case where the protocol is not specified,
1080 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1081 */
1082MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1083MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1084MODULE_LICENSE("GPL");
1085MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1086MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");