?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Linux 2.6.18.8
[linux-2.6/suspend2-2.6.18.git] / net / dccp / ipv4.c
blob7f56f7e8f57169aa77e2a3e49a66514cca5367e7
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/module.h>
16 #include <linux/skbuff.h>
17 #include <linux/random.h>
18
19 #include <net/icmp.h>
20 #include <net/inet_common.h>
21 #include <net/inet_hashtables.h>
22 #include <net/inet_sock.h>
23 #include <net/protocol.h>
24 #include <net/sock.h>
25 #include <net/timewait_sock.h>
26 #include <net/tcp_states.h>
27 #include <net/xfrm.h>
28
29 #include "ackvec.h"
30 #include "ccid.h"
31 #include "dccp.h"
32 #include "feat.h"
33
34 /*
35 * This is the global socket data structure used for responding to
36 * the Out-of-the-blue (OOTB) packets. A control sock will be created
37 * for this socket at the initialization time.
38 */
39 static struct socket *dccp_v4_ctl_socket;
40
41 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
42 {
43 return inet_csk_get_port(&dccp_hashinfo, sk, snum,
44 inet_csk_bind_conflict);
45 }
46
47 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
48 {
49 struct inet_sock *inet = inet_sk(sk);
50 struct dccp_sock *dp = dccp_sk(sk);
51 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
52 struct rtable *rt;
53 u32 daddr, nexthop;
54 int tmp;
55 int err;
56
57 dp->dccps_role = DCCP_ROLE_CLIENT;
58
59 if (dccp_service_not_initialized(sk))
60 return -EPROTO;
61
62 if (addr_len < sizeof(struct sockaddr_in))
63 return -EINVAL;
64
65 if (usin->sin_family != AF_INET)
66 return -EAFNOSUPPORT;
67
68 nexthop = daddr = usin->sin_addr.s_addr;
69 if (inet->opt != NULL && inet->opt->srr) {
70 if (daddr == 0)
71 return -EINVAL;
72 nexthop = inet->opt->faddr;
73 }
74
75 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
76 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
77 IPPROTO_DCCP,
78 inet->sport, usin->sin_port, sk);
79 if (tmp < 0)
80 return tmp;
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->srr)
88 daddr = rt->rt_dst;
89
90 if (inet->saddr == 0)
91 inet->saddr = rt->rt_src;
92 inet->rcv_saddr = inet->saddr;
93
94 inet->dport = usin->sin_port;
95 inet->daddr = daddr;
96
97 inet_csk(sk)->icsk_ext_hdr_len = 0;
98 if (inet->opt != NULL)
99 inet_csk(sk)->icsk_ext_hdr_len = inet->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 err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
112 sk);
113 if (err != 0)
114 goto failure;
115
116 /* OK, now commit destination to socket. */
117 sk_setup_caps(sk, &rt->u.dst);
118
119 dp->dccps_gar =
120 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
121 inet->daddr,
122 inet->sport,
123 usin->sin_port);
124 dccp_update_gss(sk, dp->dccps_iss);
125
126 inet->id = dp->dccps_iss ^ jiffies;
127
128 err = dccp_connect(sk);
129 rt = NULL;
130 if (err != 0)
131 goto failure;
132 out:
133 return err;
134 failure:
135 /*
136 * This unhashes the socket and releases the local port, if necessary.
137 */
138 dccp_set_state(sk, DCCP_CLOSED);
139 ip_rt_put(rt);
140 sk->sk_route_caps = 0;
141 inet->dport = 0;
142 goto out;
143 }
144
145 EXPORT_SYMBOL_GPL(dccp_v4_connect);
146
147 /*
148 * This routine does path mtu discovery as defined in RFC1191.
149 */
150 static inline void dccp_do_pmtu_discovery(struct sock *sk,
151 const struct iphdr *iph,
152 u32 mtu)
153 {
154 struct dst_entry *dst;
155 const struct inet_sock *inet = inet_sk(sk);
156 const struct dccp_sock *dp = dccp_sk(sk);
157
158 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
159 * send out by Linux are always < 576bytes so they should go through
160 * unfragmented).
161 */
162 if (sk->sk_state == DCCP_LISTEN)
163 return;
164
165 /* We don't check in the destentry if pmtu discovery is forbidden
166 * on this route. We just assume that no packet_to_big packets
167 * are send back when pmtu discovery is not active.
168 * There is a small race when the user changes this flag in the
169 * route, but I think that's acceptable.
170 */
171 if ((dst = __sk_dst_check(sk, 0)) == NULL)
172 return;
173
174 dst->ops->update_pmtu(dst, mtu);
175
176 /* Something is about to be wrong... Remember soft error
177 * for the case, if this connection will not able to recover.
178 */
179 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
180 sk->sk_err_soft = EMSGSIZE;
181
182 mtu = dst_mtu(dst);
183
184 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
185 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
186 dccp_sync_mss(sk, mtu);
187
188 /*
189 * From: draft-ietf-dccp-spec-11.txt
190 *
191 * DCCP-Sync packets are the best choice for upward
192 * probing, since DCCP-Sync probes do not risk application
193 * data loss.
194 */
195 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
196 } /* else let the usual retransmit timer handle it */
197 }
198
199 static void dccp_v4_reqsk_send_ack(struct sk_buff *rxskb,
200 struct request_sock *req)
201 {
202 int err;
203 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
204 const u32 dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
205 sizeof(struct dccp_hdr_ext) +
206 sizeof(struct dccp_hdr_ack_bits);
207 struct sk_buff *skb;
208
209 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
210 return;
211
212 skb = alloc_skb(dccp_v4_ctl_socket->sk->sk_prot->max_header, GFP_ATOMIC);
213 if (skb == NULL)
214 return;
215
216 /* Reserve space for headers. */
217 skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header);
218
219 skb->dst = dst_clone(rxskb->dst);
220
221 skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
222 dh = dccp_hdr(skb);
223 memset(dh, 0, dccp_hdr_ack_len);
224
225 /* Build DCCP header and checksum it. */
226 dh->dccph_type = DCCP_PKT_ACK;
227 dh->dccph_sport = rxdh->dccph_dport;
228 dh->dccph_dport = rxdh->dccph_sport;
229 dh->dccph_doff = dccp_hdr_ack_len / 4;
230 dh->dccph_x = 1;
231
232 dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
233 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
234 DCCP_SKB_CB(rxskb)->dccpd_seq);
235
236 bh_lock_sock(dccp_v4_ctl_socket->sk);
237 err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
238 rxskb->nh.iph->daddr,
239 rxskb->nh.iph->saddr, NULL);
240 bh_unlock_sock(dccp_v4_ctl_socket->sk);
241
242 if (err == NET_XMIT_CN || err == 0) {
243 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
244 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
245 }
246 }
247
248 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
249 struct dst_entry *dst)
250 {
251 int err = -1;
252 struct sk_buff *skb;
253
254 /* First, grab a route. */
255
256 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
257 goto out;
258
259 skb = dccp_make_response(sk, dst, req);
260 if (skb != NULL) {
261 const struct inet_request_sock *ireq = inet_rsk(req);
262 struct dccp_hdr *dh = dccp_hdr(skb);
263
264 dh->dccph_checksum = dccp_v4_checksum(skb, ireq->loc_addr,
265 ireq->rmt_addr);
266 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
267 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
268 ireq->rmt_addr,
269 ireq->opt);
270 if (err == NET_XMIT_CN)
271 err = 0;
272 }
273
274 out:
275 dst_release(dst);
276 return err;
277 }
278
279 /*
280 * This routine is called by the ICMP module when it gets some sort of error
281 * condition. If err < 0 then the socket should be closed and the error
282 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
283 * After adjustment header points to the first 8 bytes of the tcp header. We
284 * need to find the appropriate port.
285 *
286 * The locking strategy used here is very "optimistic". When someone else
287 * accesses the socket the ICMP is just dropped and for some paths there is no
288 * check at all. A more general error queue to queue errors for later handling
289 * is probably better.
290 */
291 static void dccp_v4_err(struct sk_buff *skb, u32 info)
292 {
293 const struct iphdr *iph = (struct iphdr *)skb->data;
294 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
295 (iph->ihl << 2));
296 struct dccp_sock *dp;
297 struct inet_sock *inet;
298 const int type = skb->h.icmph->type;
299 const int code = skb->h.icmph->code;
300 struct sock *sk;
301 __u64 seq;
302 int err;
303
304 if (skb->len < (iph->ihl << 2) + 8) {
305 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
306 return;
307 }
308
309 sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
310 iph->saddr, dh->dccph_sport, inet_iif(skb));
311 if (sk == NULL) {
312 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
313 return;
314 }
315
316 if (sk->sk_state == DCCP_TIME_WAIT) {
317 inet_twsk_put((struct inet_timewait_sock *)sk);
318 return;
319 }
320
321 bh_lock_sock(sk);
322 /* If too many ICMPs get dropped on busy
323 * servers this needs to be solved differently.
324 */
325 if (sock_owned_by_user(sk))
326 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
327
328 if (sk->sk_state == DCCP_CLOSED)
329 goto out;
330
331 dp = dccp_sk(sk);
332 seq = dccp_hdr_seq(skb);
333 if (sk->sk_state != DCCP_LISTEN &&
334 !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
335 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
336 goto out;
337 }
338
339 switch (type) {
340 case ICMP_SOURCE_QUENCH:
341 /* Just silently ignore these. */
342 goto out;
343 case ICMP_PARAMETERPROB:
344 err = EPROTO;
345 break;
346 case ICMP_DEST_UNREACH:
347 if (code > NR_ICMP_UNREACH)
348 goto out;
349
350 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
351 if (!sock_owned_by_user(sk))
352 dccp_do_pmtu_discovery(sk, iph, info);
353 goto out;
354 }
355
356 err = icmp_err_convert[code].errno;
357 break;
358 case ICMP_TIME_EXCEEDED:
359 err = EHOSTUNREACH;
360 break;
361 default:
362 goto out;
363 }
364
365 switch (sk->sk_state) {
366 struct request_sock *req , **prev;
367 case DCCP_LISTEN:
368 if (sock_owned_by_user(sk))
369 goto out;
370 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
371 iph->daddr, iph->saddr);
372 if (!req)
373 goto out;
374
375 /*
376 * ICMPs are not backlogged, hence we cannot get an established
377 * socket here.
378 */
379 BUG_TRAP(!req->sk);
380
381 if (seq != dccp_rsk(req)->dreq_iss) {
382 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
383 goto out;
384 }
385 /*
386 * Still in RESPOND, just remove it silently.
387 * There is no good way to pass the error to the newly
388 * created socket, and POSIX does not want network
389 * errors returned from accept().
390 */
391 inet_csk_reqsk_queue_drop(sk, req, prev);
392 goto out;
393
394 case DCCP_REQUESTING:
395 case DCCP_RESPOND:
396 if (!sock_owned_by_user(sk)) {
397 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
398 sk->sk_err = err;
399
400 sk->sk_error_report(sk);
401
402 dccp_done(sk);
403 } else
404 sk->sk_err_soft = err;
405 goto out;
406 }
407
408 /* If we've already connected we will keep trying
409 * until we time out, or the user gives up.
410 *
411 * rfc1122 4.2.3.9 allows to consider as hard errors
412 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
413 * but it is obsoleted by pmtu discovery).
414 *
415 * Note, that in modern internet, where routing is unreliable
416 * and in each dark corner broken firewalls sit, sending random
417 * errors ordered by their masters even this two messages finally lose
418 * their original sense (even Linux sends invalid PORT_UNREACHs)
419 *
420 * Now we are in compliance with RFCs.
421 * --ANK (980905)
422 */
423
424 inet = inet_sk(sk);
425 if (!sock_owned_by_user(sk) && inet->recverr) {
426 sk->sk_err = err;
427 sk->sk_error_report(sk);
428 } else /* Only an error on timeout */
429 sk->sk_err_soft = err;
430 out:
431 bh_unlock_sock(sk);
432 sock_put(sk);
433 }
434
435 /* This routine computes an IPv4 DCCP checksum. */
436 void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
437 {
438 const struct inet_sock *inet = inet_sk(sk);
439 struct dccp_hdr *dh = dccp_hdr(skb);
440
441 dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr, inet->daddr);
442 }
443
444 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
445
446 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
447 const struct sk_buff *skb)
448 {
449 return secure_dccp_sequence_number(skb->nh.iph->daddr,
450 skb->nh.iph->saddr,
451 dccp_hdr(skb)->dccph_dport,
452 dccp_hdr(skb)->dccph_sport);
453 }
454
455 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
456 {
457 struct inet_request_sock *ireq;
458 struct dccp_sock dp;
459 struct request_sock *req;
460 struct dccp_request_sock *dreq;
461 const __be32 saddr = skb->nh.iph->saddr;
462 const __be32 daddr = skb->nh.iph->daddr;
463 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
464 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
465 __u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
466
467 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
468 if (((struct rtable *)skb->dst)->rt_flags &
469 (RTCF_BROADCAST | RTCF_MULTICAST)) {
470 reset_code = DCCP_RESET_CODE_NO_CONNECTION;
471 goto drop;
472 }
473
474 if (dccp_bad_service_code(sk, service)) {
475 reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
476 goto drop;
477 }
478 /*
479 * TW buckets are converted to open requests without
480 * limitations, they conserve resources and peer is
481 * evidently real one.
482 */
483 if (inet_csk_reqsk_queue_is_full(sk))
484 goto drop;
485
486 /*
487 * Accept backlog is full. If we have already queued enough
488 * of warm entries in syn queue, drop request. It is better than
489 * clogging syn queue with openreqs with exponentially increasing
490 * timeout.
491 */
492 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
493 goto drop;
494
495 req = reqsk_alloc(sk->sk_prot->rsk_prot);
496 if (req == NULL)
497 goto drop;
498
499 if (dccp_parse_options(sk, skb))
500 goto drop_and_free;
501
502 dccp_openreq_init(req, &dp, skb);
503
504 ireq = inet_rsk(req);
505 ireq->loc_addr = daddr;
506 ireq->rmt_addr = saddr;
507 req->rcv_wnd = dccp_feat_default_sequence_window;
508 ireq->opt = NULL;
509
510 /*
511 * Step 3: Process LISTEN state
512 *
513 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
514 *
515 * In fact we defer setting S.GSR, S.SWL, S.SWH to
516 * dccp_create_openreq_child.
517 */
518 dreq = dccp_rsk(req);
519 dreq->dreq_isr = dcb->dccpd_seq;
520 dreq->dreq_iss = dccp_v4_init_sequence(sk, skb);
521 dreq->dreq_service = service;
522
523 if (dccp_v4_send_response(sk, req, NULL))
524 goto drop_and_free;
525
526 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
527 return 0;
528
529 drop_and_free:
530 reqsk_free(req);
531 drop:
532 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
533 dcb->dccpd_reset_code = reset_code;
534 return -1;
535 }
536
537 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
538
539 /*
540 * The three way handshake has completed - we got a valid ACK or DATAACK -
541 * now create the new socket.
542 *
543 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
544 */
545 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
546 struct request_sock *req,
547 struct dst_entry *dst)
548 {
549 struct inet_request_sock *ireq;
550 struct inet_sock *newinet;
551 struct dccp_sock *newdp;
552 struct sock *newsk;
553
554 if (sk_acceptq_is_full(sk))
555 goto exit_overflow;
556
557 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
558 goto exit;
559
560 newsk = dccp_create_openreq_child(sk, req, skb);
561 if (newsk == NULL)
562 goto exit;
563
564 sk_setup_caps(newsk, dst);
565
566 newdp = dccp_sk(newsk);
567 newinet = inet_sk(newsk);
568 ireq = inet_rsk(req);
569 newinet->daddr = ireq->rmt_addr;
570 newinet->rcv_saddr = ireq->loc_addr;
571 newinet->saddr = ireq->loc_addr;
572 newinet->opt = ireq->opt;
573 ireq->opt = NULL;
574 newinet->mc_index = inet_iif(skb);
575 newinet->mc_ttl = skb->nh.iph->ttl;
576 newinet->id = jiffies;
577
578 dccp_sync_mss(newsk, dst_mtu(dst));
579
580 __inet_hash(&dccp_hashinfo, newsk, 0);
581 __inet_inherit_port(&dccp_hashinfo, sk, newsk);
582
583 return newsk;
584
585 exit_overflow:
586 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
587 exit:
588 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
589 dst_release(dst);
590 return NULL;
591 }
592
593 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
594
595 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
596 {
597 const struct dccp_hdr *dh = dccp_hdr(skb);
598 const struct iphdr *iph = skb->nh.iph;
599 struct sock *nsk;
600 struct request_sock **prev;
601 /* Find possible connection requests. */
602 struct request_sock *req = inet_csk_search_req(sk, &prev,
603 dh->dccph_sport,
604 iph->saddr, iph->daddr);
605 if (req != NULL)
606 return dccp_check_req(sk, skb, req, prev);
607
608 nsk = __inet_lookup_established(&dccp_hashinfo,
609 iph->saddr, dh->dccph_sport,
610 iph->daddr, ntohs(dh->dccph_dport),
611 inet_iif(skb));
612 if (nsk != NULL) {
613 if (nsk->sk_state != DCCP_TIME_WAIT) {
614 bh_lock_sock(nsk);
615 return nsk;
616 }
617 inet_twsk_put((struct inet_timewait_sock *)nsk);
618 return NULL;
619 }
620
621 return sk;
622 }
623
624 int dccp_v4_checksum(const struct sk_buff *skb, const __be32 saddr,
625 const __be32 daddr)
626 {
627 const struct dccp_hdr* dh = dccp_hdr(skb);
628 int checksum_len;
629 u32 tmp;
630
631 if (dh->dccph_cscov == 0)
632 checksum_len = skb->len;
633 else {
634 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
635 checksum_len = checksum_len < skb->len ? checksum_len :
636 skb->len;
637 }
638
639 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
640 return csum_tcpudp_magic(saddr, daddr, checksum_len,
641 IPPROTO_DCCP, tmp);
642 }
643
644 EXPORT_SYMBOL_GPL(dccp_v4_checksum);
645
646 static int dccp_v4_verify_checksum(struct sk_buff *skb,
647 const __be32 saddr, const __be32 daddr)
648 {
649 struct dccp_hdr *dh = dccp_hdr(skb);
650 int checksum_len;
651 u32 tmp;
652
653 if (dh->dccph_cscov == 0)
654 checksum_len = skb->len;
655 else {
656 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
657 checksum_len = checksum_len < skb->len ? checksum_len :
658 skb->len;
659 }
660 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
661 return csum_tcpudp_magic(saddr, daddr, checksum_len,
662 IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
663 }
664
665 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
666 struct sk_buff *skb)
667 {
668 struct rtable *rt;
669 struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
670 .nl_u = { .ip4_u =
671 { .daddr = skb->nh.iph->saddr,
672 .saddr = skb->nh.iph->daddr,
673 .tos = RT_CONN_FLAGS(sk) } },
674 .proto = sk->sk_protocol,
675 .uli_u = { .ports =
676 { .sport = dccp_hdr(skb)->dccph_dport,
677 .dport = dccp_hdr(skb)->dccph_sport }
678 }
679 };
680
681 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
682 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
683 return NULL;
684 }
685
686 return &rt->u.dst;
687 }
688
689 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
690 {
691 int err;
692 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
693 const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
694 sizeof(struct dccp_hdr_ext) +
695 sizeof(struct dccp_hdr_reset);
696 struct sk_buff *skb;
697 struct dst_entry *dst;
698 u64 seqno;
699
700 /* Never send a reset in response to a reset. */
701 if (rxdh->dccph_type == DCCP_PKT_RESET)
702 return;
703
704 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
705 return;
706
707 dst = dccp_v4_route_skb(dccp_v4_ctl_socket->sk, rxskb);
708 if (dst == NULL)
709 return;
710
711 skb = alloc_skb(dccp_v4_ctl_socket->sk->sk_prot->max_header,
712 GFP_ATOMIC);
713 if (skb == NULL)
714 goto out;
715
716 /* Reserve space for headers. */
717 skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header);
718 skb->dst = dst_clone(dst);
719
720 skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
721 dh = dccp_hdr(skb);
722 memset(dh, 0, dccp_hdr_reset_len);
723
724 /* Build DCCP header and checksum it. */
725 dh->dccph_type = DCCP_PKT_RESET;
726 dh->dccph_sport = rxdh->dccph_dport;
727 dh->dccph_dport = rxdh->dccph_sport;
728 dh->dccph_doff = dccp_hdr_reset_len / 4;
729 dh->dccph_x = 1;
730 dccp_hdr_reset(skb)->dccph_reset_code =
731 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
732
733 /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
734 seqno = 0;
735 if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
736 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
737
738 dccp_hdr_set_seq(dh, seqno);
739 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
740 DCCP_SKB_CB(rxskb)->dccpd_seq);
741
742 dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
743 rxskb->nh.iph->daddr);
744
745 bh_lock_sock(dccp_v4_ctl_socket->sk);
746 err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
747 rxskb->nh.iph->daddr,
748 rxskb->nh.iph->saddr, NULL);
749 bh_unlock_sock(dccp_v4_ctl_socket->sk);
750
751 if (err == NET_XMIT_CN || err == 0) {
752 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
753 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
754 }
755 out:
756 dst_release(dst);
757 }
758
759 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
760 {
761 struct dccp_hdr *dh = dccp_hdr(skb);
762
763 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
764 if (dccp_rcv_established(sk, skb, dh, skb->len))
765 goto reset;
766 return 0;
767 }
768
769 /*
770 * Step 3: Process LISTEN state
771 * If S.state == LISTEN,
772 * If P.type == Request or P contains a valid Init Cookie
773 * option,
774 * * Must scan the packet's options to check for an Init
775 * Cookie. Only the Init Cookie is processed here,
776 * however; other options are processed in Step 8. This
777 * scan need only be performed if the endpoint uses Init
778 * Cookies *
779 * * Generate a new socket and switch to that socket *
780 * Set S := new socket for this port pair
781 * S.state = RESPOND
782 * Choose S.ISS (initial seqno) or set from Init Cookie
783 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
784 * Continue with S.state == RESPOND
785 * * A Response packet will be generated in Step 11 *
786 * Otherwise,
787 * Generate Reset(No Connection) unless P.type == Reset
788 * Drop packet and return
789 *
790 * NOTE: the check for the packet types is done in
791 * dccp_rcv_state_process
792 */
793 if (sk->sk_state == DCCP_LISTEN) {
794 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
795
796 if (nsk == NULL)
797 goto discard;
798
799 if (nsk != sk) {
800 if (dccp_child_process(sk, nsk, skb))
801 goto reset;
802 return 0;
803 }
804 }
805
806 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
807 goto reset;
808 return 0;
809
810 reset:
811 dccp_v4_ctl_send_reset(skb);
812 discard:
813 kfree_skb(skb);
814 return 0;
815 }
816
817 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
818
819 int dccp_invalid_packet(struct sk_buff *skb)
820 {
821 const struct dccp_hdr *dh;
822
823 if (skb->pkt_type != PACKET_HOST)
824 return 1;
825
826 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
827 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
828 return 1;
829 }
830
831 dh = dccp_hdr(skb);
832
833 /* If the packet type is not understood, drop packet and return */
834 if (dh->dccph_type >= DCCP_PKT_INVALID) {
835 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
836 return 1;
837 }
838
839 /*
840 * If P.Data Offset is too small for packet type, or too large for
841 * packet, drop packet and return
842 */
843 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
844 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
845 "too small 1\n",
846 dh->dccph_doff);
847 return 1;
848 }
849
850 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
851 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
852 "too small 2\n",
853 dh->dccph_doff);
854 return 1;
855 }
856
857 dh = dccp_hdr(skb);
858
859 /*
860 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
861 * has short sequence numbers), drop packet and return
862 */
863 if (dh->dccph_x == 0 &&
864 dh->dccph_type != DCCP_PKT_DATA &&
865 dh->dccph_type != DCCP_PKT_ACK &&
866 dh->dccph_type != DCCP_PKT_DATAACK) {
867 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
868 "nor DataAck and P.X == 0\n",
869 dccp_packet_name(dh->dccph_type));
870 return 1;
871 }
872
873 return 0;
874 }
875
876 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
877
878 /* this is called when real data arrives */
879 static int dccp_v4_rcv(struct sk_buff *skb)
880 {
881 const struct dccp_hdr *dh;
882 struct sock *sk;
883
884 /* Step 1: Check header basics: */
885
886 if (dccp_invalid_packet(skb))
887 goto discard_it;
888
889 /* If the header checksum is incorrect, drop packet and return */
890 if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
891 skb->nh.iph->daddr) < 0) {
892 LIMIT_NETDEBUG(KERN_WARNING "%s: incorrect header checksum\n",
893 __FUNCTION__);
894 goto discard_it;
895 }
896
897 dh = dccp_hdr(skb);
898
899 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
900 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
901
902 dccp_pr_debug("%8.8s "
903 "src=%u.%u.%u.%u@%-5d "
904 "dst=%u.%u.%u.%u@%-5d seq=%llu",
905 dccp_packet_name(dh->dccph_type),
906 NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
907 NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
908 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
909
910 if (dccp_packet_without_ack(skb)) {
911 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
912 dccp_pr_debug_cat("\n");
913 } else {
914 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
915 dccp_pr_debug_cat(", ack=%llu\n",
916 (unsigned long long)
917 DCCP_SKB_CB(skb)->dccpd_ack_seq);
918 }
919
920 /* Step 2:
921 * Look up flow ID in table and get corresponding socket */
922 sk = __inet_lookup(&dccp_hashinfo,
923 skb->nh.iph->saddr, dh->dccph_sport,
924 skb->nh.iph->daddr, ntohs(dh->dccph_dport),
925 inet_iif(skb));
926
927 /*
928 * Step 2:
929 * If no socket ...
930 * Generate Reset(No Connection) unless P.type == Reset
931 * Drop packet and return
932 */
933 if (sk == NULL) {
934 dccp_pr_debug("failed to look up flow ID in table and "
935 "get corresponding socket\n");
936 goto no_dccp_socket;
937 }
938
939 /*
940 * Step 2:
941 * ... or S.state == TIMEWAIT,
942 * Generate Reset(No Connection) unless P.type == Reset
943 * Drop packet and return
944 */
945
946 if (sk->sk_state == DCCP_TIME_WAIT) {
947 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
948 "do_time_wait\n");
949 goto do_time_wait;
950 }
951
952 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
953 goto discard_and_relse;
954 nf_reset(skb);
955
956 return sk_receive_skb(sk, skb);
957
958 no_dccp_socket:
959 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
960 goto discard_it;
961 /*
962 * Step 2:
963 * Generate Reset(No Connection) unless P.type == Reset
964 * Drop packet and return
965 */
966 if (dh->dccph_type != DCCP_PKT_RESET) {
967 DCCP_SKB_CB(skb)->dccpd_reset_code =
968 DCCP_RESET_CODE_NO_CONNECTION;
969 dccp_v4_ctl_send_reset(skb);
970 }
971
972 discard_it:
973 /* Discard frame. */
974 kfree_skb(skb);
975 return 0;
976
977 discard_and_relse:
978 sock_put(sk);
979 goto discard_it;
980
981 do_time_wait:
982 inet_twsk_put((struct inet_timewait_sock *)sk);
983 goto no_dccp_socket;
984 }
985
986 static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
987 .queue_xmit = ip_queue_xmit,
988 .send_check = dccp_v4_send_check,
989 .rebuild_header = inet_sk_rebuild_header,
990 .conn_request = dccp_v4_conn_request,
991 .syn_recv_sock = dccp_v4_request_recv_sock,
992 .net_header_len = sizeof(struct iphdr),
993 .setsockopt = ip_setsockopt,
994 .getsockopt = ip_getsockopt,
995 .addr2sockaddr = inet_csk_addr2sockaddr,
996 .sockaddr_len = sizeof(struct sockaddr_in),
997 #ifdef CONFIG_COMPAT
998 .compat_setsockopt = compat_ip_setsockopt,
999 .compat_getsockopt = compat_ip_getsockopt,
1000 #endif
1001 };
1002
1003 static int dccp_v4_init_sock(struct sock *sk)
1004 {
1005 static __u8 dccp_v4_ctl_sock_initialized;
1006 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
1007
1008 if (err == 0) {
1009 if (unlikely(!dccp_v4_ctl_sock_initialized))
1010 dccp_v4_ctl_sock_initialized = 1;
1011 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
1012 }
1013
1014 return err;
1015 }
1016
1017 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1018 {
1019 kfree(inet_rsk(req)->opt);
1020 }
1021
1022 static struct request_sock_ops dccp_request_sock_ops = {
1023 .family = PF_INET,
1024 .obj_size = sizeof(struct dccp_request_sock),
1025 .rtx_syn_ack = dccp_v4_send_response,
1026 .send_ack = dccp_v4_reqsk_send_ack,
1027 .destructor = dccp_v4_reqsk_destructor,
1028 .send_reset = dccp_v4_ctl_send_reset,
1029 };
1030
1031 static struct timewait_sock_ops dccp_timewait_sock_ops = {
1032 .twsk_obj_size = sizeof(struct inet_timewait_sock),
1033 };
1034
1035 static struct proto dccp_v4_prot = {
1036 .name = "DCCP",
1037 .owner = THIS_MODULE,
1038 .close = dccp_close,
1039 .connect = dccp_v4_connect,
1040 .disconnect = dccp_disconnect,
1041 .ioctl = dccp_ioctl,
1042 .init = dccp_v4_init_sock,
1043 .setsockopt = dccp_setsockopt,
1044 .getsockopt = dccp_getsockopt,
1045 .sendmsg = dccp_sendmsg,
1046 .recvmsg = dccp_recvmsg,
1047 .backlog_rcv = dccp_v4_do_rcv,
1048 .hash = dccp_hash,
1049 .unhash = dccp_unhash,
1050 .accept = inet_csk_accept,
1051 .get_port = dccp_v4_get_port,
1052 .shutdown = dccp_shutdown,
1053 .destroy = dccp_destroy_sock,
1054 .orphan_count = &dccp_orphan_count,
1055 .max_header = MAX_DCCP_HEADER,
1056 .obj_size = sizeof(struct dccp_sock),
1057 .rsk_prot = &dccp_request_sock_ops,
1058 .twsk_prot = &dccp_timewait_sock_ops,
1059 #ifdef CONFIG_COMPAT
1060 .compat_setsockopt = compat_dccp_setsockopt,
1061 .compat_getsockopt = compat_dccp_getsockopt,
1062 #endif
1063 };
1064
1065 static struct net_protocol dccp_v4_protocol = {
1066 .handler = dccp_v4_rcv,
1067 .err_handler = dccp_v4_err,
1068 .no_policy = 1,
1069 };
1070
1071 static const struct proto_ops inet_dccp_ops = {
1072 .family = PF_INET,
1073 .owner = THIS_MODULE,
1074 .release = inet_release,
1075 .bind = inet_bind,
1076 .connect = inet_stream_connect,
1077 .socketpair = sock_no_socketpair,
1078 .accept = inet_accept,
1079 .getname = inet_getname,
1080 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1081 .poll = dccp_poll,
1082 .ioctl = inet_ioctl,
1083 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1084 .listen = inet_dccp_listen,
1085 .shutdown = inet_shutdown,
1086 .setsockopt = sock_common_setsockopt,
1087 .getsockopt = sock_common_getsockopt,
1088 .sendmsg = inet_sendmsg,
1089 .recvmsg = sock_common_recvmsg,
1090 .mmap = sock_no_mmap,
1091 .sendpage = sock_no_sendpage,
1092 #ifdef CONFIG_COMPAT
1093 .compat_setsockopt = compat_sock_common_setsockopt,
1094 .compat_getsockopt = compat_sock_common_getsockopt,
1095 #endif
1096 };
1097
1098 static struct inet_protosw dccp_v4_protosw = {
1099 .type = SOCK_DCCP,
1100 .protocol = IPPROTO_DCCP,
1101 .prot = &dccp_v4_prot,
1102 .ops = &inet_dccp_ops,
1103 .capability = -1,
1104 .no_check = 0,
1105 .flags = INET_PROTOSW_ICSK,
1106 };
1107
1108 static int __init dccp_v4_init(void)
1109 {
1110 int err = proto_register(&dccp_v4_prot, 1);
1111
1112 if (err != 0)
1113 goto out;
1114
1115 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1116 if (err != 0)
1117 goto out_proto_unregister;
1118
1119 inet_register_protosw(&dccp_v4_protosw);
1120
1121 err = inet_csk_ctl_sock_create(&dccp_v4_ctl_socket, PF_INET,
1122 SOCK_DCCP, IPPROTO_DCCP);
1123 if (err)
1124 goto out_unregister_protosw;
1125 out:
1126 return err;
1127 out_unregister_protosw:
1128 inet_unregister_protosw(&dccp_v4_protosw);
1129 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1130 out_proto_unregister:
1131 proto_unregister(&dccp_v4_prot);
1132 goto out;
1133 }
1134
1135 static void __exit dccp_v4_exit(void)
1136 {
1137 inet_unregister_protosw(&dccp_v4_protosw);
1138 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1139 proto_unregister(&dccp_v4_prot);
1140 }
1141
1142 module_init(dccp_v4_init);
1143 module_exit(dccp_v4_exit);
1144
1145 /*
1146 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1147 * values directly, Also cover the case where the protocol is not specified,
1148 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1149 */
1150 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-33-type-6");
1151 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-0-type-6");
1152 MODULE_LICENSE("GPL");
1153 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1154 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");
Software Suspend 2 for 2.6.18.y (mirror)