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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/*
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 err = PTR_ERR(rt);
115 rt = NULL;
116 goto failure;
117 }
118 /* OK, now commit destination to socket. */
119 sk_setup_caps(sk, &rt->dst);
120
121 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
122 inet->inet_daddr,
123 inet->inet_sport,
124 inet->inet_dport);
125 inet->inet_id = dp->dccps_iss ^ jiffies;
126
127 err = dccp_connect(sk);
128 rt = NULL;
129 if (err != 0)
130 goto failure;
131out:
132 return err;
133failure:
134 /*
135 * This unhashes the socket and releases the local port, if necessary.
136 */
137 dccp_set_state(sk, DCCP_CLOSED);
138 ip_rt_put(rt);
139 sk->sk_route_caps = 0;
140 inet->inet_dport = 0;
141 goto out;
142}
143
144EXPORT_SYMBOL_GPL(dccp_v4_connect);
145
146/*
147 * This routine does path mtu discovery as defined in RFC1191.
148 */
149static inline void dccp_do_pmtu_discovery(struct sock *sk,
150 const struct iphdr *iph,
151 u32 mtu)
152{
153 struct dst_entry *dst;
154 const struct inet_sock *inet = inet_sk(sk);
155 const struct dccp_sock *dp = dccp_sk(sk);
156
157 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
158 * send out by Linux are always < 576bytes so they should go through
159 * unfragmented).
160 */
161 if (sk->sk_state == DCCP_LISTEN)
162 return;
163
164 /* We don't check in the destentry if pmtu discovery is forbidden
165 * on this route. We just assume that no packet_to_big packets
166 * are send back when pmtu discovery is not active.
167 * There is a small race when the user changes this flag in the
168 * route, but I think that's acceptable.
169 */
170 if ((dst = __sk_dst_check(sk, 0)) == NULL)
171 return;
172
173 dst->ops->update_pmtu(dst, mtu);
174
175 /* Something is about to be wrong... Remember soft error
176 * for the case, if this connection will not able to recover.
177 */
178 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
179 sk->sk_err_soft = EMSGSIZE;
180
181 mtu = dst_mtu(dst);
182
183 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
184 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
185 dccp_sync_mss(sk, mtu);
186
187 /*
188 * From RFC 4340, sec. 14.1:
189 *
190 * DCCP-Sync packets are the best choice for upward
191 * probing, since DCCP-Sync probes do not risk application
192 * data loss.
193 */
194 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
195 } /* else let the usual retransmit timer handle it */
196}
197
198/*
199 * This routine is called by the ICMP module when it gets some sort of error
200 * condition. If err < 0 then the socket should be closed and the error
201 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
202 * After adjustment header points to the first 8 bytes of the tcp header. We
203 * need to find the appropriate port.
204 *
205 * The locking strategy used here is very "optimistic". When someone else
206 * accesses the socket the ICMP is just dropped and for some paths there is no
207 * check at all. A more general error queue to queue errors for later handling
208 * is probably better.
209 */
210static void dccp_v4_err(struct sk_buff *skb, u32 info)
211{
212 const struct iphdr *iph = (struct iphdr *)skb->data;
213 const u8 offset = iph->ihl << 2;
214 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
215 struct dccp_sock *dp;
216 struct inet_sock *inet;
217 const int type = icmp_hdr(skb)->type;
218 const int code = icmp_hdr(skb)->code;
219 struct sock *sk;
220 __u64 seq;
221 int err;
222 struct net *net = dev_net(skb->dev);
223
224 if (skb->len < offset + sizeof(*dh) ||
225 skb->len < offset + __dccp_basic_hdr_len(dh)) {
226 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
227 return;
228 }
229
230 sk = inet_lookup(net, &dccp_hashinfo,
231 iph->daddr, dh->dccph_dport,
232 iph->saddr, dh->dccph_sport, inet_iif(skb));
233 if (sk == NULL) {
234 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
235 return;
236 }
237
238 if (sk->sk_state == DCCP_TIME_WAIT) {
239 inet_twsk_put(inet_twsk(sk));
240 return;
241 }
242
243 bh_lock_sock(sk);
244 /* If too many ICMPs get dropped on busy
245 * servers this needs to be solved differently.
246 */
247 if (sock_owned_by_user(sk))
248 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
249
250 if (sk->sk_state == DCCP_CLOSED)
251 goto out;
252
253 dp = dccp_sk(sk);
254 seq = dccp_hdr_seq(dh);
255 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
256 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
257 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
258 goto out;
259 }
260
261 switch (type) {
262 case ICMP_SOURCE_QUENCH:
263 /* Just silently ignore these. */
264 goto out;
265 case ICMP_PARAMETERPROB:
266 err = EPROTO;
267 break;
268 case ICMP_DEST_UNREACH:
269 if (code > NR_ICMP_UNREACH)
270 goto out;
271
272 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
273 if (!sock_owned_by_user(sk))
274 dccp_do_pmtu_discovery(sk, iph, info);
275 goto out;
276 }
277
278 err = icmp_err_convert[code].errno;
279 break;
280 case ICMP_TIME_EXCEEDED:
281 err = EHOSTUNREACH;
282 break;
283 default:
284 goto out;
285 }
286
287 switch (sk->sk_state) {
288 struct request_sock *req , **prev;
289 case DCCP_LISTEN:
290 if (sock_owned_by_user(sk))
291 goto out;
292 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
293 iph->daddr, iph->saddr);
294 if (!req)
295 goto out;
296
297 /*
298 * ICMPs are not backlogged, hence we cannot get an established
299 * socket here.
300 */
301 WARN_ON(req->sk);
302
303 if (!between48(seq, dccp_rsk(req)->dreq_iss,
304 dccp_rsk(req)->dreq_gss)) {
305 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
306 goto out;
307 }
308 /*
309 * Still in RESPOND, just remove it silently.
310 * There is no good way to pass the error to the newly
311 * created socket, and POSIX does not want network
312 * errors returned from accept().
313 */
314 inet_csk_reqsk_queue_drop(sk, req, prev);
315 goto out;
316
317 case DCCP_REQUESTING:
318 case DCCP_RESPOND:
319 if (!sock_owned_by_user(sk)) {
320 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
321 sk->sk_err = err;
322
323 sk->sk_error_report(sk);
324
325 dccp_done(sk);
326 } else
327 sk->sk_err_soft = err;
328 goto out;
329 }
330
331 /* If we've already connected we will keep trying
332 * until we time out, or the user gives up.
333 *
334 * rfc1122 4.2.3.9 allows to consider as hard errors
335 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
336 * but it is obsoleted by pmtu discovery).
337 *
338 * Note, that in modern internet, where routing is unreliable
339 * and in each dark corner broken firewalls sit, sending random
340 * errors ordered by their masters even this two messages finally lose
341 * their original sense (even Linux sends invalid PORT_UNREACHs)
342 *
343 * Now we are in compliance with RFCs.
344 * --ANK (980905)
345 */
346
347 inet = inet_sk(sk);
348 if (!sock_owned_by_user(sk) && inet->recverr) {
349 sk->sk_err = err;
350 sk->sk_error_report(sk);
351 } else /* Only an error on timeout */
352 sk->sk_err_soft = err;
353out:
354 bh_unlock_sock(sk);
355 sock_put(sk);
356}
357
358static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
359 __be32 src, __be32 dst)
360{
361 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
362}
363
364void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
365{
366 const struct inet_sock *inet = inet_sk(sk);
367 struct dccp_hdr *dh = dccp_hdr(skb);
368
369 dccp_csum_outgoing(skb);
370 dh->dccph_checksum = dccp_v4_csum_finish(skb,
371 inet->inet_saddr,
372 inet->inet_daddr);
373}
374
375EXPORT_SYMBOL_GPL(dccp_v4_send_check);
376
377static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
378{
379 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
380 ip_hdr(skb)->saddr,
381 dccp_hdr(skb)->dccph_dport,
382 dccp_hdr(skb)->dccph_sport);
383}
384
385/*
386 * The three way handshake has completed - we got a valid ACK or DATAACK -
387 * now create the new socket.
388 *
389 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
390 */
391struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
392 struct request_sock *req,
393 struct dst_entry *dst)
394{
395 struct inet_request_sock *ireq;
396 struct inet_sock *newinet;
397 struct sock *newsk;
398
399 if (sk_acceptq_is_full(sk))
400 goto exit_overflow;
401
402 newsk = dccp_create_openreq_child(sk, req, skb);
403 if (newsk == NULL)
404 goto exit_nonewsk;
405
406 newinet = inet_sk(newsk);
407 ireq = inet_rsk(req);
408 newinet->inet_daddr = ireq->rmt_addr;
409 newinet->inet_rcv_saddr = ireq->loc_addr;
410 newinet->inet_saddr = ireq->loc_addr;
411 newinet->inet_opt = ireq->opt;
412 ireq->opt = NULL;
413 newinet->mc_index = inet_iif(skb);
414 newinet->mc_ttl = ip_hdr(skb)->ttl;
415 newinet->inet_id = jiffies;
416
417 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
418 goto put_and_exit;
419
420 sk_setup_caps(newsk, dst);
421
422 dccp_sync_mss(newsk, dst_mtu(dst));
423
424 if (__inet_inherit_port(sk, newsk) < 0)
425 goto put_and_exit;
426 __inet_hash_nolisten(newsk, NULL);
427
428 return newsk;
429
430exit_overflow:
431 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
432exit_nonewsk:
433 dst_release(dst);
434exit:
435 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
436 return NULL;
437put_and_exit:
438 bh_unlock_sock(newsk);
439 sock_put(newsk);
440 goto exit;
441}
442
443EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
444
445static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
446{
447 const struct dccp_hdr *dh = dccp_hdr(skb);
448 const struct iphdr *iph = ip_hdr(skb);
449 struct sock *nsk;
450 struct request_sock **prev;
451 /* Find possible connection requests. */
452 struct request_sock *req = inet_csk_search_req(sk, &prev,
453 dh->dccph_sport,
454 iph->saddr, iph->daddr);
455 if (req != NULL)
456 return dccp_check_req(sk, skb, req, prev);
457
458 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
459 iph->saddr, dh->dccph_sport,
460 iph->daddr, dh->dccph_dport,
461 inet_iif(skb));
462 if (nsk != NULL) {
463 if (nsk->sk_state != DCCP_TIME_WAIT) {
464 bh_lock_sock(nsk);
465 return nsk;
466 }
467 inet_twsk_put(inet_twsk(nsk));
468 return NULL;
469 }
470
471 return sk;
472}
473
474static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
475 struct sk_buff *skb)
476{
477 struct rtable *rt;
478 const struct iphdr *iph = ip_hdr(skb);
479 struct flowi4 fl4 = {
480 .flowi4_oif = skb_rtable(skb)->rt_iif,
481 .daddr = iph->saddr,
482 .saddr = iph->daddr,
483 .flowi4_tos = RT_CONN_FLAGS(sk),
484 .flowi4_proto = sk->sk_protocol,
485 .fl4_sport = dccp_hdr(skb)->dccph_dport,
486 .fl4_dport = dccp_hdr(skb)->dccph_sport,
487 };
488
489 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
490 rt = ip_route_output_flow(net, &fl4, sk);
491 if (IS_ERR(rt)) {
492 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
493 return NULL;
494 }
495
496 return &rt->dst;
497}
498
499static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
500 struct request_values *rv_unused)
501{
502 int err = -1;
503 struct sk_buff *skb;
504 struct dst_entry *dst;
505 struct flowi4 fl4;
506
507 dst = inet_csk_route_req(sk, &fl4, req);
508 if (dst == NULL)
509 goto out;
510
511 skb = dccp_make_response(sk, dst, req);
512 if (skb != NULL) {
513 const struct inet_request_sock *ireq = inet_rsk(req);
514 struct dccp_hdr *dh = dccp_hdr(skb);
515
516 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
517 ireq->rmt_addr);
518 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
519 ireq->rmt_addr,
520 ireq->opt);
521 err = net_xmit_eval(err);
522 }
523
524out:
525 dst_release(dst);
526 return err;
527}
528
529static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
530{
531 int err;
532 const struct iphdr *rxiph;
533 struct sk_buff *skb;
534 struct dst_entry *dst;
535 struct net *net = dev_net(skb_dst(rxskb)->dev);
536 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
537
538 /* Never send a reset in response to a reset. */
539 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
540 return;
541
542 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
543 return;
544
545 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
546 if (dst == NULL)
547 return;
548
549 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
550 if (skb == NULL)
551 goto out;
552
553 rxiph = ip_hdr(rxskb);
554 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
555 rxiph->daddr);
556 skb_dst_set(skb, dst_clone(dst));
557
558 bh_lock_sock(ctl_sk);
559 err = ip_build_and_send_pkt(skb, ctl_sk,
560 rxiph->daddr, rxiph->saddr, NULL);
561 bh_unlock_sock(ctl_sk);
562
563 if (net_xmit_eval(err) == 0) {
564 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
565 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
566 }
567out:
568 dst_release(dst);
569}
570
571static void dccp_v4_reqsk_destructor(struct request_sock *req)
572{
573 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
574 kfree(inet_rsk(req)->opt);
575}
576
577void dccp_syn_ack_timeout(struct sock *sk, struct request_sock *req)
578{
579}
580EXPORT_SYMBOL(dccp_syn_ack_timeout);
581
582static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
583 .family = PF_INET,
584 .obj_size = sizeof(struct dccp_request_sock),
585 .rtx_syn_ack = dccp_v4_send_response,
586 .send_ack = dccp_reqsk_send_ack,
587 .destructor = dccp_v4_reqsk_destructor,
588 .send_reset = dccp_v4_ctl_send_reset,
589 .syn_ack_timeout = dccp_syn_ack_timeout,
590};
591
592int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
593{
594 struct inet_request_sock *ireq;
595 struct request_sock *req;
596 struct dccp_request_sock *dreq;
597 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
598 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
599
600 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
601 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
602 return 0; /* discard, don't send a reset here */
603
604 if (dccp_bad_service_code(sk, service)) {
605 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
606 goto drop;
607 }
608 /*
609 * TW buckets are converted to open requests without
610 * limitations, they conserve resources and peer is
611 * evidently real one.
612 */
613 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
614 if (inet_csk_reqsk_queue_is_full(sk))
615 goto drop;
616
617 /*
618 * Accept backlog is full. If we have already queued enough
619 * of warm entries in syn queue, drop request. It is better than
620 * clogging syn queue with openreqs with exponentially increasing
621 * timeout.
622 */
623 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
624 goto drop;
625
626 req = inet_reqsk_alloc(&dccp_request_sock_ops);
627 if (req == NULL)
628 goto drop;
629
630 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
631 goto drop_and_free;
632
633 dreq = dccp_rsk(req);
634 if (dccp_parse_options(sk, dreq, skb))
635 goto drop_and_free;
636
637 if (security_inet_conn_request(sk, skb, req))
638 goto drop_and_free;
639
640 ireq = inet_rsk(req);
641 ireq->loc_addr = ip_hdr(skb)->daddr;
642 ireq->rmt_addr = ip_hdr(skb)->saddr;
643
644 /*
645 * Step 3: Process LISTEN state
646 *
647 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
648 *
649 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
650 */
651 dreq->dreq_isr = dcb->dccpd_seq;
652 dreq->dreq_gsr = dreq->dreq_isr;
653 dreq->dreq_iss = dccp_v4_init_sequence(skb);
654 dreq->dreq_gss = dreq->dreq_iss;
655 dreq->dreq_service = service;
656
657 if (dccp_v4_send_response(sk, req, NULL))
658 goto drop_and_free;
659
660 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
661 return 0;
662
663drop_and_free:
664 reqsk_free(req);
665drop:
666 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
667 return -1;
668}
669
670EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
671
672int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
673{
674 struct dccp_hdr *dh = dccp_hdr(skb);
675
676 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
677 if (dccp_rcv_established(sk, skb, dh, skb->len))
678 goto reset;
679 return 0;
680 }
681
682 /*
683 * Step 3: Process LISTEN state
684 * If P.type == Request or P contains a valid Init Cookie option,
685 * (* Must scan the packet's options to check for Init
686 * Cookies. Only Init Cookies are processed here,
687 * however; other options are processed in Step 8. This
688 * scan need only be performed if the endpoint uses Init
689 * Cookies *)
690 * (* Generate a new socket and switch to that socket *)
691 * Set S := new socket for this port pair
692 * S.state = RESPOND
693 * Choose S.ISS (initial seqno) or set from Init Cookies
694 * Initialize S.GAR := S.ISS
695 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
696 * Continue with S.state == RESPOND
697 * (* A Response packet will be generated in Step 11 *)
698 * Otherwise,
699 * Generate Reset(No Connection) unless P.type == Reset
700 * Drop packet and return
701 *
702 * NOTE: the check for the packet types is done in
703 * dccp_rcv_state_process
704 */
705 if (sk->sk_state == DCCP_LISTEN) {
706 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
707
708 if (nsk == NULL)
709 goto discard;
710
711 if (nsk != sk) {
712 if (dccp_child_process(sk, nsk, skb))
713 goto reset;
714 return 0;
715 }
716 }
717
718 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
719 goto reset;
720 return 0;
721
722reset:
723 dccp_v4_ctl_send_reset(sk, skb);
724discard:
725 kfree_skb(skb);
726 return 0;
727}
728
729EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
730
731/**
732 * dccp_invalid_packet - check for malformed packets
733 * Implements RFC 4340, 8.5: Step 1: Check header basics
734 * Packets that fail these checks are ignored and do not receive Resets.
735 */
736int dccp_invalid_packet(struct sk_buff *skb)
737{
738 const struct dccp_hdr *dh;
739 unsigned int cscov;
740
741 if (skb->pkt_type != PACKET_HOST)
742 return 1;
743
744 /* If the packet is shorter than 12 bytes, drop packet and return */
745 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
746 DCCP_WARN("pskb_may_pull failed\n");
747 return 1;
748 }
749
750 dh = dccp_hdr(skb);
751
752 /* If P.type is not understood, drop packet and return */
753 if (dh->dccph_type >= DCCP_PKT_INVALID) {
754 DCCP_WARN("invalid packet type\n");
755 return 1;
756 }
757
758 /*
759 * If P.Data Offset is too small for packet type, drop packet and return
760 */
761 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
762 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
763 return 1;
764 }
765 /*
766 * If P.Data Offset is too too large for packet, drop packet and return
767 */
768 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
769 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
770 return 1;
771 }
772
773 /*
774 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
775 * has short sequence numbers), drop packet and return
776 */
777 if ((dh->dccph_type < DCCP_PKT_DATA ||
778 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
779 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
780 dccp_packet_name(dh->dccph_type));
781 return 1;
782 }
783
784 /*
785 * If P.CsCov is too large for the packet size, drop packet and return.
786 * This must come _before_ checksumming (not as RFC 4340 suggests).
787 */
788 cscov = dccp_csum_coverage(skb);
789 if (cscov > skb->len) {
790 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
791 dh->dccph_cscov, skb->len);
792 return 1;
793 }
794
795 /* If header checksum is incorrect, drop packet and return.
796 * (This step is completed in the AF-dependent functions.) */
797 skb->csum = skb_checksum(skb, 0, cscov, 0);
798
799 return 0;
800}
801
802EXPORT_SYMBOL_GPL(dccp_invalid_packet);
803
804/* this is called when real data arrives */
805static int dccp_v4_rcv(struct sk_buff *skb)
806{
807 const struct dccp_hdr *dh;
808 const struct iphdr *iph;
809 struct sock *sk;
810 int min_cov;
811
812 /* Step 1: Check header basics */
813
814 if (dccp_invalid_packet(skb))
815 goto discard_it;
816
817 iph = ip_hdr(skb);
818 /* Step 1: If header checksum is incorrect, drop packet and return */
819 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
820 DCCP_WARN("dropped packet with invalid checksum\n");
821 goto discard_it;
822 }
823
824 dh = dccp_hdr(skb);
825
826 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
827 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
828
829 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
830 dccp_packet_name(dh->dccph_type),
831 &iph->saddr, ntohs(dh->dccph_sport),
832 &iph->daddr, ntohs(dh->dccph_dport),
833 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
834
835 if (dccp_packet_without_ack(skb)) {
836 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
837 dccp_pr_debug_cat("\n");
838 } else {
839 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
840 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
841 DCCP_SKB_CB(skb)->dccpd_ack_seq);
842 }
843
844 /* Step 2:
845 * Look up flow ID in table and get corresponding socket */
846 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
847 dh->dccph_sport, dh->dccph_dport);
848 /*
849 * Step 2:
850 * If no socket ...
851 */
852 if (sk == NULL) {
853 dccp_pr_debug("failed to look up flow ID in table and "
854 "get corresponding socket\n");
855 goto no_dccp_socket;
856 }
857
858 /*
859 * Step 2:
860 * ... or S.state == TIMEWAIT,
861 * Generate Reset(No Connection) unless P.type == Reset
862 * Drop packet and return
863 */
864 if (sk->sk_state == DCCP_TIME_WAIT) {
865 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
866 inet_twsk_put(inet_twsk(sk));
867 goto no_dccp_socket;
868 }
869
870 /*
871 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
872 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
873 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
874 */
875 min_cov = dccp_sk(sk)->dccps_pcrlen;
876 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
877 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
878 dh->dccph_cscov, min_cov);
879 /* FIXME: "Such packets SHOULD be reported using Data Dropped
880 * options (Section 11.7) with Drop Code 0, Protocol
881 * Constraints." */
882 goto discard_and_relse;
883 }
884
885 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
886 goto discard_and_relse;
887 nf_reset(skb);
888
889 return sk_receive_skb(sk, skb, 1);
890
891no_dccp_socket:
892 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
893 goto discard_it;
894 /*
895 * Step 2:
896 * If no socket ...
897 * Generate Reset(No Connection) unless P.type == Reset
898 * Drop packet and return
899 */
900 if (dh->dccph_type != DCCP_PKT_RESET) {
901 DCCP_SKB_CB(skb)->dccpd_reset_code =
902 DCCP_RESET_CODE_NO_CONNECTION;
903 dccp_v4_ctl_send_reset(sk, skb);
904 }
905
906discard_it:
907 kfree_skb(skb);
908 return 0;
909
910discard_and_relse:
911 sock_put(sk);
912 goto discard_it;
913}
914
915static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
916 .queue_xmit = ip_queue_xmit,
917 .send_check = dccp_v4_send_check,
918 .rebuild_header = inet_sk_rebuild_header,
919 .conn_request = dccp_v4_conn_request,
920 .syn_recv_sock = dccp_v4_request_recv_sock,
921 .net_header_len = sizeof(struct iphdr),
922 .setsockopt = ip_setsockopt,
923 .getsockopt = ip_getsockopt,
924 .addr2sockaddr = inet_csk_addr2sockaddr,
925 .sockaddr_len = sizeof(struct sockaddr_in),
926 .bind_conflict = inet_csk_bind_conflict,
927#ifdef CONFIG_COMPAT
928 .compat_setsockopt = compat_ip_setsockopt,
929 .compat_getsockopt = compat_ip_getsockopt,
930#endif
931};
932
933static int dccp_v4_init_sock(struct sock *sk)
934{
935 static __u8 dccp_v4_ctl_sock_initialized;
936 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
937
938 if (err == 0) {
939 if (unlikely(!dccp_v4_ctl_sock_initialized))
940 dccp_v4_ctl_sock_initialized = 1;
941 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
942 }
943
944 return err;
945}
946
947static struct timewait_sock_ops dccp_timewait_sock_ops = {
948 .twsk_obj_size = sizeof(struct inet_timewait_sock),
949};
950
951static struct proto dccp_v4_prot = {
952 .name = "DCCP",
953 .owner = THIS_MODULE,
954 .close = dccp_close,
955 .connect = dccp_v4_connect,
956 .disconnect = dccp_disconnect,
957 .ioctl = dccp_ioctl,
958 .init = dccp_v4_init_sock,
959 .setsockopt = dccp_setsockopt,
960 .getsockopt = dccp_getsockopt,
961 .sendmsg = dccp_sendmsg,
962 .recvmsg = dccp_recvmsg,
963 .backlog_rcv = dccp_v4_do_rcv,
964 .hash = inet_hash,
965 .unhash = inet_unhash,
966 .accept = inet_csk_accept,
967 .get_port = inet_csk_get_port,
968 .shutdown = dccp_shutdown,
969 .destroy = dccp_destroy_sock,
970 .orphan_count = &dccp_orphan_count,
971 .max_header = MAX_DCCP_HEADER,
972 .obj_size = sizeof(struct dccp_sock),
973 .slab_flags = SLAB_DESTROY_BY_RCU,
974 .rsk_prot = &dccp_request_sock_ops,
975 .twsk_prot = &dccp_timewait_sock_ops,
976 .h.hashinfo = &dccp_hashinfo,
977#ifdef CONFIG_COMPAT
978 .compat_setsockopt = compat_dccp_setsockopt,
979 .compat_getsockopt = compat_dccp_getsockopt,
980#endif
981};
982
983static const struct net_protocol dccp_v4_protocol = {
984 .handler = dccp_v4_rcv,
985 .err_handler = dccp_v4_err,
986 .no_policy = 1,
987 .netns_ok = 1,
988};
989
990static const struct proto_ops inet_dccp_ops = {
991 .family = PF_INET,
992 .owner = THIS_MODULE,
993 .release = inet_release,
994 .bind = inet_bind,
995 .connect = inet_stream_connect,
996 .socketpair = sock_no_socketpair,
997 .accept = inet_accept,
998 .getname = inet_getname,
999 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1000 .poll = dccp_poll,
1001 .ioctl = inet_ioctl,
1002 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1003 .listen = inet_dccp_listen,
1004 .shutdown = inet_shutdown,
1005 .setsockopt = sock_common_setsockopt,
1006 .getsockopt = sock_common_getsockopt,
1007 .sendmsg = inet_sendmsg,
1008 .recvmsg = sock_common_recvmsg,
1009 .mmap = sock_no_mmap,
1010 .sendpage = sock_no_sendpage,
1011#ifdef CONFIG_COMPAT
1012 .compat_setsockopt = compat_sock_common_setsockopt,
1013 .compat_getsockopt = compat_sock_common_getsockopt,
1014#endif
1015};
1016
1017static struct inet_protosw dccp_v4_protosw = {
1018 .type = SOCK_DCCP,
1019 .protocol = IPPROTO_DCCP,
1020 .prot = &dccp_v4_prot,
1021 .ops = &inet_dccp_ops,
1022 .no_check = 0,
1023 .flags = INET_PROTOSW_ICSK,
1024};
1025
1026static int __net_init dccp_v4_init_net(struct net *net)
1027{
1028 if (dccp_hashinfo.bhash == NULL)
1029 return -ESOCKTNOSUPPORT;
1030
1031 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1032 SOCK_DCCP, IPPROTO_DCCP, net);
1033}
1034
1035static void __net_exit dccp_v4_exit_net(struct net *net)
1036{
1037 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1038}
1039
1040static struct pernet_operations dccp_v4_ops = {
1041 .init = dccp_v4_init_net,
1042 .exit = dccp_v4_exit_net,
1043};
1044
1045static int __init dccp_v4_init(void)
1046{
1047 int err = proto_register(&dccp_v4_prot, 1);
1048
1049 if (err != 0)
1050 goto out;
1051
1052 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1053 if (err != 0)
1054 goto out_proto_unregister;
1055
1056 inet_register_protosw(&dccp_v4_protosw);
1057
1058 err = register_pernet_subsys(&dccp_v4_ops);
1059 if (err)
1060 goto out_destroy_ctl_sock;
1061out:
1062 return err;
1063out_destroy_ctl_sock:
1064 inet_unregister_protosw(&dccp_v4_protosw);
1065 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1066out_proto_unregister:
1067 proto_unregister(&dccp_v4_prot);
1068 goto out;
1069}
1070
1071static void __exit dccp_v4_exit(void)
1072{
1073 unregister_pernet_subsys(&dccp_v4_ops);
1074 inet_unregister_protosw(&dccp_v4_protosw);
1075 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1076 proto_unregister(&dccp_v4_prot);
1077}
1078
1079module_init(dccp_v4_init);
1080module_exit(dccp_v4_exit);
1081
1082/*
1083 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1084 * values directly, Also cover the case where the protocol is not specified,
1085 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1086 */
1087MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1088MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1089MODULE_LICENSE("GPL");
1090MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1091MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");