inet: add RCU protection to inet->opt
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / dccp / ipv4.c
blobcbbcc6c036e0275b3714af5bb5bc23761660edd3
1 /*
2 * net/dccp/ipv4.c
4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
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>
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>
30 #include "ackvec.h"
31 #include "ccid.h"
32 #include "dccp.h"
33 #include "feat.h"
36 * The per-net dccp.v4_ctl_sk socket is used for responding to
37 * the Out-of-the-blue (OOTB) packets. A control sock will be created
38 * for this socket at the initialization time.
41 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
43 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
44 struct inet_sock *inet = inet_sk(sk);
45 struct dccp_sock *dp = dccp_sk(sk);
46 __be16 orig_sport, orig_dport;
47 __be32 daddr, nexthop;
48 struct flowi4 fl4;
49 struct rtable *rt;
50 int err;
51 struct ip_options_rcu *inet_opt;
53 dp->dccps_role = DCCP_ROLE_CLIENT;
55 if (addr_len < sizeof(struct sockaddr_in))
56 return -EINVAL;
58 if (usin->sin_family != AF_INET)
59 return -EAFNOSUPPORT;
61 nexthop = daddr = usin->sin_addr.s_addr;
63 inet_opt = rcu_dereference_protected(inet->inet_opt,
64 sock_owned_by_user(sk));
65 if (inet_opt != NULL && inet_opt->opt.srr) {
66 if (daddr == 0)
67 return -EINVAL;
68 nexthop = inet_opt->opt.faddr;
71 orig_sport = inet->inet_sport;
72 orig_dport = usin->sin_port;
73 rt = ip_route_connect(&fl4, nexthop, inet->inet_saddr,
74 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
75 IPPROTO_DCCP,
76 orig_sport, orig_dport, sk, true);
77 if (IS_ERR(rt))
78 return PTR_ERR(rt);
80 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
81 ip_rt_put(rt);
82 return -ENETUNREACH;
85 if (inet_opt == NULL || !inet_opt->opt.srr)
86 daddr = rt->rt_dst;
88 if (inet->inet_saddr == 0)
89 inet->inet_saddr = rt->rt_src;
90 inet->inet_rcv_saddr = inet->inet_saddr;
92 inet->inet_dport = usin->sin_port;
93 inet->inet_daddr = daddr;
95 inet_csk(sk)->icsk_ext_hdr_len = 0;
96 if (inet_opt)
97 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
99 * Socket identity is still unknown (sport may be zero).
100 * However we set state to DCCP_REQUESTING and not releasing socket
101 * lock select source port, enter ourselves into the hash tables and
102 * complete initialization after this.
104 dccp_set_state(sk, DCCP_REQUESTING);
105 err = inet_hash_connect(&dccp_death_row, sk);
106 if (err != 0)
107 goto failure;
109 rt = ip_route_newports(&fl4, rt, orig_sport, orig_dport,
110 inet->inet_sport, inet->inet_dport, sk);
111 if (IS_ERR(rt)) {
112 rt = NULL;
113 goto failure;
115 /* OK, now commit destination to socket. */
116 sk_setup_caps(sk, &rt->dst);
118 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
119 inet->inet_daddr,
120 inet->inet_sport,
121 inet->inet_dport);
122 inet->inet_id = dp->dccps_iss ^ jiffies;
124 err = dccp_connect(sk);
125 rt = NULL;
126 if (err != 0)
127 goto failure;
128 out:
129 return err;
130 failure:
132 * This unhashes the socket and releases the local port, if necessary.
134 dccp_set_state(sk, DCCP_CLOSED);
135 ip_rt_put(rt);
136 sk->sk_route_caps = 0;
137 inet->inet_dport = 0;
138 goto out;
141 EXPORT_SYMBOL_GPL(dccp_v4_connect);
144 * This routine does path mtu discovery as defined in RFC1191.
146 static inline void dccp_do_pmtu_discovery(struct sock *sk,
147 const struct iphdr *iph,
148 u32 mtu)
150 struct dst_entry *dst;
151 const struct inet_sock *inet = inet_sk(sk);
152 const struct dccp_sock *dp = dccp_sk(sk);
154 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
155 * send out by Linux are always < 576bytes so they should go through
156 * unfragmented).
158 if (sk->sk_state == DCCP_LISTEN)
159 return;
161 /* We don't check in the destentry if pmtu discovery is forbidden
162 * on this route. We just assume that no packet_to_big packets
163 * are send back when pmtu discovery is not active.
164 * There is a small race when the user changes this flag in the
165 * route, but I think that's acceptable.
167 if ((dst = __sk_dst_check(sk, 0)) == NULL)
168 return;
170 dst->ops->update_pmtu(dst, mtu);
172 /* Something is about to be wrong... Remember soft error
173 * for the case, if this connection will not able to recover.
175 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
176 sk->sk_err_soft = EMSGSIZE;
178 mtu = dst_mtu(dst);
180 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
181 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
182 dccp_sync_mss(sk, mtu);
185 * From RFC 4340, sec. 14.1:
187 * DCCP-Sync packets are the best choice for upward
188 * probing, since DCCP-Sync probes do not risk application
189 * data loss.
191 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
192 } /* else let the usual retransmit timer handle it */
196 * This routine is called by the ICMP module when it gets some sort of error
197 * condition. If err < 0 then the socket should be closed and the error
198 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
199 * After adjustment header points to the first 8 bytes of the tcp header. We
200 * need to find the appropriate port.
202 * The locking strategy used here is very "optimistic". When someone else
203 * accesses the socket the ICMP is just dropped and for some paths there is no
204 * check at all. A more general error queue to queue errors for later handling
205 * is probably better.
207 static void dccp_v4_err(struct sk_buff *skb, u32 info)
209 const struct iphdr *iph = (struct iphdr *)skb->data;
210 const u8 offset = iph->ihl << 2;
211 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
212 struct dccp_sock *dp;
213 struct inet_sock *inet;
214 const int type = icmp_hdr(skb)->type;
215 const int code = icmp_hdr(skb)->code;
216 struct sock *sk;
217 __u64 seq;
218 int err;
219 struct net *net = dev_net(skb->dev);
221 if (skb->len < offset + sizeof(*dh) ||
222 skb->len < offset + __dccp_basic_hdr_len(dh)) {
223 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
224 return;
227 sk = inet_lookup(net, &dccp_hashinfo,
228 iph->daddr, dh->dccph_dport,
229 iph->saddr, dh->dccph_sport, inet_iif(skb));
230 if (sk == NULL) {
231 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
232 return;
235 if (sk->sk_state == DCCP_TIME_WAIT) {
236 inet_twsk_put(inet_twsk(sk));
237 return;
240 bh_lock_sock(sk);
241 /* If too many ICMPs get dropped on busy
242 * servers this needs to be solved differently.
244 if (sock_owned_by_user(sk))
245 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
247 if (sk->sk_state == DCCP_CLOSED)
248 goto out;
250 dp = dccp_sk(sk);
251 seq = dccp_hdr_seq(dh);
252 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
253 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
254 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
255 goto out;
258 switch (type) {
259 case ICMP_SOURCE_QUENCH:
260 /* Just silently ignore these. */
261 goto out;
262 case ICMP_PARAMETERPROB:
263 err = EPROTO;
264 break;
265 case ICMP_DEST_UNREACH:
266 if (code > NR_ICMP_UNREACH)
267 goto out;
269 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
270 if (!sock_owned_by_user(sk))
271 dccp_do_pmtu_discovery(sk, iph, info);
272 goto out;
275 err = icmp_err_convert[code].errno;
276 break;
277 case ICMP_TIME_EXCEEDED:
278 err = EHOSTUNREACH;
279 break;
280 default:
281 goto out;
284 switch (sk->sk_state) {
285 struct request_sock *req , **prev;
286 case DCCP_LISTEN:
287 if (sock_owned_by_user(sk))
288 goto out;
289 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
290 iph->daddr, iph->saddr);
291 if (!req)
292 goto out;
295 * ICMPs are not backlogged, hence we cannot get an established
296 * socket here.
298 WARN_ON(req->sk);
300 if (seq != dccp_rsk(req)->dreq_iss) {
301 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
302 goto out;
305 * Still in RESPOND, just remove it silently.
306 * There is no good way to pass the error to the newly
307 * created socket, and POSIX does not want network
308 * errors returned from accept().
310 inet_csk_reqsk_queue_drop(sk, req, prev);
311 goto out;
313 case DCCP_REQUESTING:
314 case DCCP_RESPOND:
315 if (!sock_owned_by_user(sk)) {
316 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
317 sk->sk_err = err;
319 sk->sk_error_report(sk);
321 dccp_done(sk);
322 } else
323 sk->sk_err_soft = err;
324 goto out;
327 /* If we've already connected we will keep trying
328 * until we time out, or the user gives up.
330 * rfc1122 4.2.3.9 allows to consider as hard errors
331 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
332 * but it is obsoleted by pmtu discovery).
334 * Note, that in modern internet, where routing is unreliable
335 * and in each dark corner broken firewalls sit, sending random
336 * errors ordered by their masters even this two messages finally lose
337 * their original sense (even Linux sends invalid PORT_UNREACHs)
339 * Now we are in compliance with RFCs.
340 * --ANK (980905)
343 inet = inet_sk(sk);
344 if (!sock_owned_by_user(sk) && inet->recverr) {
345 sk->sk_err = err;
346 sk->sk_error_report(sk);
347 } else /* Only an error on timeout */
348 sk->sk_err_soft = err;
349 out:
350 bh_unlock_sock(sk);
351 sock_put(sk);
354 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
355 __be32 src, __be32 dst)
357 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
360 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
362 const struct inet_sock *inet = inet_sk(sk);
363 struct dccp_hdr *dh = dccp_hdr(skb);
365 dccp_csum_outgoing(skb);
366 dh->dccph_checksum = dccp_v4_csum_finish(skb,
367 inet->inet_saddr,
368 inet->inet_daddr);
371 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
373 static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
375 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
376 ip_hdr(skb)->saddr,
377 dccp_hdr(skb)->dccph_dport,
378 dccp_hdr(skb)->dccph_sport);
382 * The three way handshake has completed - we got a valid ACK or DATAACK -
383 * now create the new socket.
385 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
387 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
388 struct request_sock *req,
389 struct dst_entry *dst)
391 struct inet_request_sock *ireq;
392 struct inet_sock *newinet;
393 struct sock *newsk;
395 if (sk_acceptq_is_full(sk))
396 goto exit_overflow;
398 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
399 goto exit;
401 newsk = dccp_create_openreq_child(sk, req, skb);
402 if (newsk == NULL)
403 goto exit_nonewsk;
405 sk_setup_caps(newsk, dst);
407 newinet = inet_sk(newsk);
408 ireq = inet_rsk(req);
409 newinet->inet_daddr = ireq->rmt_addr;
410 newinet->inet_rcv_saddr = ireq->loc_addr;
411 newinet->inet_saddr = ireq->loc_addr;
412 newinet->inet_opt = ireq->opt;
413 ireq->opt = NULL;
414 newinet->mc_index = inet_iif(skb);
415 newinet->mc_ttl = ip_hdr(skb)->ttl;
416 newinet->inet_id = jiffies;
418 dccp_sync_mss(newsk, dst_mtu(dst));
420 if (__inet_inherit_port(sk, newsk) < 0) {
421 sock_put(newsk);
422 goto exit;
424 __inet_hash_nolisten(newsk, NULL);
426 return newsk;
428 exit_overflow:
429 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
430 exit_nonewsk:
431 dst_release(dst);
432 exit:
433 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
434 return NULL;
437 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
439 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
441 const struct dccp_hdr *dh = dccp_hdr(skb);
442 const struct iphdr *iph = ip_hdr(skb);
443 struct sock *nsk;
444 struct request_sock **prev;
445 /* Find possible connection requests. */
446 struct request_sock *req = inet_csk_search_req(sk, &prev,
447 dh->dccph_sport,
448 iph->saddr, iph->daddr);
449 if (req != NULL)
450 return dccp_check_req(sk, skb, req, prev);
452 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
453 iph->saddr, dh->dccph_sport,
454 iph->daddr, dh->dccph_dport,
455 inet_iif(skb));
456 if (nsk != NULL) {
457 if (nsk->sk_state != DCCP_TIME_WAIT) {
458 bh_lock_sock(nsk);
459 return nsk;
461 inet_twsk_put(inet_twsk(nsk));
462 return NULL;
465 return sk;
468 static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
469 struct sk_buff *skb)
471 struct rtable *rt;
472 struct flowi4 fl4 = {
473 .flowi4_oif = skb_rtable(skb)->rt_iif,
474 .daddr = ip_hdr(skb)->saddr,
475 .saddr = ip_hdr(skb)->daddr,
476 .flowi4_tos = RT_CONN_FLAGS(sk),
477 .flowi4_proto = sk->sk_protocol,
478 .fl4_sport = dccp_hdr(skb)->dccph_dport,
479 .fl4_dport = dccp_hdr(skb)->dccph_sport,
482 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
483 rt = ip_route_output_flow(net, &fl4, sk);
484 if (IS_ERR(rt)) {
485 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
486 return NULL;
489 return &rt->dst;
492 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
493 struct request_values *rv_unused)
495 int err = -1;
496 struct sk_buff *skb;
497 struct dst_entry *dst;
499 dst = inet_csk_route_req(sk, req);
500 if (dst == NULL)
501 goto out;
503 skb = dccp_make_response(sk, dst, req);
504 if (skb != NULL) {
505 const struct inet_request_sock *ireq = inet_rsk(req);
506 struct dccp_hdr *dh = dccp_hdr(skb);
508 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
509 ireq->rmt_addr);
510 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
511 ireq->rmt_addr,
512 ireq->opt);
513 err = net_xmit_eval(err);
516 out:
517 dst_release(dst);
518 return err;
521 static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
523 int err;
524 const struct iphdr *rxiph;
525 struct sk_buff *skb;
526 struct dst_entry *dst;
527 struct net *net = dev_net(skb_dst(rxskb)->dev);
528 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
530 /* Never send a reset in response to a reset. */
531 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
532 return;
534 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
535 return;
537 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
538 if (dst == NULL)
539 return;
541 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
542 if (skb == NULL)
543 goto out;
545 rxiph = ip_hdr(rxskb);
546 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
547 rxiph->daddr);
548 skb_dst_set(skb, dst_clone(dst));
550 bh_lock_sock(ctl_sk);
551 err = ip_build_and_send_pkt(skb, ctl_sk,
552 rxiph->daddr, rxiph->saddr, NULL);
553 bh_unlock_sock(ctl_sk);
555 if (net_xmit_eval(err) == 0) {
556 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
557 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
559 out:
560 dst_release(dst);
563 static void dccp_v4_reqsk_destructor(struct request_sock *req)
565 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
566 kfree(inet_rsk(req)->opt);
569 static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
570 .family = PF_INET,
571 .obj_size = sizeof(struct dccp_request_sock),
572 .rtx_syn_ack = dccp_v4_send_response,
573 .send_ack = dccp_reqsk_send_ack,
574 .destructor = dccp_v4_reqsk_destructor,
575 .send_reset = dccp_v4_ctl_send_reset,
578 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
580 struct inet_request_sock *ireq;
581 struct request_sock *req;
582 struct dccp_request_sock *dreq;
583 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
584 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
586 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
587 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
588 return 0; /* discard, don't send a reset here */
590 if (dccp_bad_service_code(sk, service)) {
591 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
592 goto drop;
595 * TW buckets are converted to open requests without
596 * limitations, they conserve resources and peer is
597 * evidently real one.
599 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
600 if (inet_csk_reqsk_queue_is_full(sk))
601 goto drop;
604 * Accept backlog is full. If we have already queued enough
605 * of warm entries in syn queue, drop request. It is better than
606 * clogging syn queue with openreqs with exponentially increasing
607 * timeout.
609 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
610 goto drop;
612 req = inet_reqsk_alloc(&dccp_request_sock_ops);
613 if (req == NULL)
614 goto drop;
616 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
617 goto drop_and_free;
619 dreq = dccp_rsk(req);
620 if (dccp_parse_options(sk, dreq, skb))
621 goto drop_and_free;
623 if (security_inet_conn_request(sk, skb, req))
624 goto drop_and_free;
626 ireq = inet_rsk(req);
627 ireq->loc_addr = ip_hdr(skb)->daddr;
628 ireq->rmt_addr = ip_hdr(skb)->saddr;
631 * Step 3: Process LISTEN state
633 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
635 * In fact we defer setting S.GSR, S.SWL, S.SWH to
636 * dccp_create_openreq_child.
638 dreq->dreq_isr = dcb->dccpd_seq;
639 dreq->dreq_iss = dccp_v4_init_sequence(skb);
640 dreq->dreq_service = service;
642 if (dccp_v4_send_response(sk, req, NULL))
643 goto drop_and_free;
645 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
646 return 0;
648 drop_and_free:
649 reqsk_free(req);
650 drop:
651 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
652 return -1;
655 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
657 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
659 struct dccp_hdr *dh = dccp_hdr(skb);
661 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
662 if (dccp_rcv_established(sk, skb, dh, skb->len))
663 goto reset;
664 return 0;
668 * Step 3: Process LISTEN state
669 * If P.type == Request or P contains a valid Init Cookie option,
670 * (* Must scan the packet's options to check for Init
671 * Cookies. Only Init Cookies are processed here,
672 * however; other options are processed in Step 8. This
673 * scan need only be performed if the endpoint uses Init
674 * Cookies *)
675 * (* Generate a new socket and switch to that socket *)
676 * Set S := new socket for this port pair
677 * S.state = RESPOND
678 * Choose S.ISS (initial seqno) or set from Init Cookies
679 * Initialize S.GAR := S.ISS
680 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
681 * Continue with S.state == RESPOND
682 * (* A Response packet will be generated in Step 11 *)
683 * Otherwise,
684 * Generate Reset(No Connection) unless P.type == Reset
685 * Drop packet and return
687 * NOTE: the check for the packet types is done in
688 * dccp_rcv_state_process
690 if (sk->sk_state == DCCP_LISTEN) {
691 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
693 if (nsk == NULL)
694 goto discard;
696 if (nsk != sk) {
697 if (dccp_child_process(sk, nsk, skb))
698 goto reset;
699 return 0;
703 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
704 goto reset;
705 return 0;
707 reset:
708 dccp_v4_ctl_send_reset(sk, skb);
709 discard:
710 kfree_skb(skb);
711 return 0;
714 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
717 * dccp_invalid_packet - check for malformed packets
718 * Implements RFC 4340, 8.5: Step 1: Check header basics
719 * Packets that fail these checks are ignored and do not receive Resets.
721 int dccp_invalid_packet(struct sk_buff *skb)
723 const struct dccp_hdr *dh;
724 unsigned int cscov;
726 if (skb->pkt_type != PACKET_HOST)
727 return 1;
729 /* If the packet is shorter than 12 bytes, drop packet and return */
730 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
731 DCCP_WARN("pskb_may_pull failed\n");
732 return 1;
735 dh = dccp_hdr(skb);
737 /* If P.type is not understood, drop packet and return */
738 if (dh->dccph_type >= DCCP_PKT_INVALID) {
739 DCCP_WARN("invalid packet type\n");
740 return 1;
744 * If P.Data Offset is too small for packet type, drop packet and return
746 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
747 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
748 return 1;
751 * If P.Data Offset is too too large for packet, drop packet and return
753 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
754 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
755 return 1;
759 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
760 * has short sequence numbers), drop packet and return
762 if ((dh->dccph_type < DCCP_PKT_DATA ||
763 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
764 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
765 dccp_packet_name(dh->dccph_type));
766 return 1;
770 * If P.CsCov is too large for the packet size, drop packet and return.
771 * This must come _before_ checksumming (not as RFC 4340 suggests).
773 cscov = dccp_csum_coverage(skb);
774 if (cscov > skb->len) {
775 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
776 dh->dccph_cscov, skb->len);
777 return 1;
780 /* If header checksum is incorrect, drop packet and return.
781 * (This step is completed in the AF-dependent functions.) */
782 skb->csum = skb_checksum(skb, 0, cscov, 0);
784 return 0;
787 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
789 /* this is called when real data arrives */
790 static int dccp_v4_rcv(struct sk_buff *skb)
792 const struct dccp_hdr *dh;
793 const struct iphdr *iph;
794 struct sock *sk;
795 int min_cov;
797 /* Step 1: Check header basics */
799 if (dccp_invalid_packet(skb))
800 goto discard_it;
802 iph = ip_hdr(skb);
803 /* Step 1: If header checksum is incorrect, drop packet and return */
804 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
805 DCCP_WARN("dropped packet with invalid checksum\n");
806 goto discard_it;
809 dh = dccp_hdr(skb);
811 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
812 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
814 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
815 dccp_packet_name(dh->dccph_type),
816 &iph->saddr, ntohs(dh->dccph_sport),
817 &iph->daddr, ntohs(dh->dccph_dport),
818 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
820 if (dccp_packet_without_ack(skb)) {
821 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
822 dccp_pr_debug_cat("\n");
823 } else {
824 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
825 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
826 DCCP_SKB_CB(skb)->dccpd_ack_seq);
829 /* Step 2:
830 * Look up flow ID in table and get corresponding socket */
831 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
832 dh->dccph_sport, dh->dccph_dport);
834 * Step 2:
835 * If no socket ...
837 if (sk == NULL) {
838 dccp_pr_debug("failed to look up flow ID in table and "
839 "get corresponding socket\n");
840 goto no_dccp_socket;
844 * Step 2:
845 * ... or S.state == TIMEWAIT,
846 * Generate Reset(No Connection) unless P.type == Reset
847 * Drop packet and return
849 if (sk->sk_state == DCCP_TIME_WAIT) {
850 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
851 inet_twsk_put(inet_twsk(sk));
852 goto no_dccp_socket;
856 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
857 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
858 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
860 min_cov = dccp_sk(sk)->dccps_pcrlen;
861 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
862 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
863 dh->dccph_cscov, min_cov);
864 /* FIXME: "Such packets SHOULD be reported using Data Dropped
865 * options (Section 11.7) with Drop Code 0, Protocol
866 * Constraints." */
867 goto discard_and_relse;
870 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
871 goto discard_and_relse;
872 nf_reset(skb);
874 return sk_receive_skb(sk, skb, 1);
876 no_dccp_socket:
877 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
878 goto discard_it;
880 * Step 2:
881 * If no socket ...
882 * Generate Reset(No Connection) unless P.type == Reset
883 * Drop packet and return
885 if (dh->dccph_type != DCCP_PKT_RESET) {
886 DCCP_SKB_CB(skb)->dccpd_reset_code =
887 DCCP_RESET_CODE_NO_CONNECTION;
888 dccp_v4_ctl_send_reset(sk, skb);
891 discard_it:
892 kfree_skb(skb);
893 return 0;
895 discard_and_relse:
896 sock_put(sk);
897 goto discard_it;
900 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
901 .queue_xmit = ip_queue_xmit,
902 .send_check = dccp_v4_send_check,
903 .rebuild_header = inet_sk_rebuild_header,
904 .conn_request = dccp_v4_conn_request,
905 .syn_recv_sock = dccp_v4_request_recv_sock,
906 .net_header_len = sizeof(struct iphdr),
907 .setsockopt = ip_setsockopt,
908 .getsockopt = ip_getsockopt,
909 .addr2sockaddr = inet_csk_addr2sockaddr,
910 .sockaddr_len = sizeof(struct sockaddr_in),
911 .bind_conflict = inet_csk_bind_conflict,
912 #ifdef CONFIG_COMPAT
913 .compat_setsockopt = compat_ip_setsockopt,
914 .compat_getsockopt = compat_ip_getsockopt,
915 #endif
918 static int dccp_v4_init_sock(struct sock *sk)
920 static __u8 dccp_v4_ctl_sock_initialized;
921 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
923 if (err == 0) {
924 if (unlikely(!dccp_v4_ctl_sock_initialized))
925 dccp_v4_ctl_sock_initialized = 1;
926 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
929 return err;
932 static struct timewait_sock_ops dccp_timewait_sock_ops = {
933 .twsk_obj_size = sizeof(struct inet_timewait_sock),
936 static struct proto dccp_v4_prot = {
937 .name = "DCCP",
938 .owner = THIS_MODULE,
939 .close = dccp_close,
940 .connect = dccp_v4_connect,
941 .disconnect = dccp_disconnect,
942 .ioctl = dccp_ioctl,
943 .init = dccp_v4_init_sock,
944 .setsockopt = dccp_setsockopt,
945 .getsockopt = dccp_getsockopt,
946 .sendmsg = dccp_sendmsg,
947 .recvmsg = dccp_recvmsg,
948 .backlog_rcv = dccp_v4_do_rcv,
949 .hash = inet_hash,
950 .unhash = inet_unhash,
951 .accept = inet_csk_accept,
952 .get_port = inet_csk_get_port,
953 .shutdown = dccp_shutdown,
954 .destroy = dccp_destroy_sock,
955 .orphan_count = &dccp_orphan_count,
956 .max_header = MAX_DCCP_HEADER,
957 .obj_size = sizeof(struct dccp_sock),
958 .slab_flags = SLAB_DESTROY_BY_RCU,
959 .rsk_prot = &dccp_request_sock_ops,
960 .twsk_prot = &dccp_timewait_sock_ops,
961 .h.hashinfo = &dccp_hashinfo,
962 #ifdef CONFIG_COMPAT
963 .compat_setsockopt = compat_dccp_setsockopt,
964 .compat_getsockopt = compat_dccp_getsockopt,
965 #endif
968 static const struct net_protocol dccp_v4_protocol = {
969 .handler = dccp_v4_rcv,
970 .err_handler = dccp_v4_err,
971 .no_policy = 1,
972 .netns_ok = 1,
975 static const struct proto_ops inet_dccp_ops = {
976 .family = PF_INET,
977 .owner = THIS_MODULE,
978 .release = inet_release,
979 .bind = inet_bind,
980 .connect = inet_stream_connect,
981 .socketpair = sock_no_socketpair,
982 .accept = inet_accept,
983 .getname = inet_getname,
984 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
985 .poll = dccp_poll,
986 .ioctl = inet_ioctl,
987 /* FIXME: work on inet_listen to rename it to sock_common_listen */
988 .listen = inet_dccp_listen,
989 .shutdown = inet_shutdown,
990 .setsockopt = sock_common_setsockopt,
991 .getsockopt = sock_common_getsockopt,
992 .sendmsg = inet_sendmsg,
993 .recvmsg = sock_common_recvmsg,
994 .mmap = sock_no_mmap,
995 .sendpage = sock_no_sendpage,
996 #ifdef CONFIG_COMPAT
997 .compat_setsockopt = compat_sock_common_setsockopt,
998 .compat_getsockopt = compat_sock_common_getsockopt,
999 #endif
1002 static struct inet_protosw dccp_v4_protosw = {
1003 .type = SOCK_DCCP,
1004 .protocol = IPPROTO_DCCP,
1005 .prot = &dccp_v4_prot,
1006 .ops = &inet_dccp_ops,
1007 .no_check = 0,
1008 .flags = INET_PROTOSW_ICSK,
1011 static int __net_init dccp_v4_init_net(struct net *net)
1013 if (dccp_hashinfo.bhash == NULL)
1014 return -ESOCKTNOSUPPORT;
1016 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1017 SOCK_DCCP, IPPROTO_DCCP, net);
1020 static void __net_exit dccp_v4_exit_net(struct net *net)
1022 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1025 static struct pernet_operations dccp_v4_ops = {
1026 .init = dccp_v4_init_net,
1027 .exit = dccp_v4_exit_net,
1030 static int __init dccp_v4_init(void)
1032 int err = proto_register(&dccp_v4_prot, 1);
1034 if (err != 0)
1035 goto out;
1037 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1038 if (err != 0)
1039 goto out_proto_unregister;
1041 inet_register_protosw(&dccp_v4_protosw);
1043 err = register_pernet_subsys(&dccp_v4_ops);
1044 if (err)
1045 goto out_destroy_ctl_sock;
1046 out:
1047 return err;
1048 out_destroy_ctl_sock:
1049 inet_unregister_protosw(&dccp_v4_protosw);
1050 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1051 out_proto_unregister:
1052 proto_unregister(&dccp_v4_prot);
1053 goto out;
1056 static void __exit dccp_v4_exit(void)
1058 unregister_pernet_subsys(&dccp_v4_ops);
1059 inet_unregister_protosw(&dccp_v4_protosw);
1060 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1061 proto_unregister(&dccp_v4_prot);
1064 module_init(dccp_v4_init);
1065 module_exit(dccp_v4_exit);
1068 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1069 * values directly, Also cover the case where the protocol is not specified,
1070 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1072 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1073 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1074 MODULE_LICENSE("GPL");
1075 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1076 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");