Linux 2.6.20.7
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / dccp / ipv4.c
blob90c74b4adb7396443a36d8124633e2d22abd5551
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/module.h>
16 #include <linux/skbuff.h>
17 #include <linux/random.h>
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>
29 #include "ackvec.h"
30 #include "ccid.h"
31 #include "dccp.h"
32 #include "feat.h"
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.
39 static struct socket *dccp_v4_ctl_socket;
41 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
43 return inet_csk_get_port(&dccp_hashinfo, sk, snum,
44 inet_csk_bind_conflict);
47 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
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 __be32 daddr, nexthop;
54 int tmp;
55 int err;
57 dp->dccps_role = DCCP_ROLE_CLIENT;
59 if (addr_len < sizeof(struct sockaddr_in))
60 return -EINVAL;
62 if (usin->sin_family != AF_INET)
63 return -EAFNOSUPPORT;
65 nexthop = daddr = usin->sin_addr.s_addr;
66 if (inet->opt != NULL && inet->opt->srr) {
67 if (daddr == 0)
68 return -EINVAL;
69 nexthop = inet->opt->faddr;
72 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
73 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
74 IPPROTO_DCCP,
75 inet->sport, usin->sin_port, sk);
76 if (tmp < 0)
77 return tmp;
79 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
80 ip_rt_put(rt);
81 return -ENETUNREACH;
84 if (inet->opt == NULL || !inet->opt->srr)
85 daddr = rt->rt_dst;
87 if (inet->saddr == 0)
88 inet->saddr = rt->rt_src;
89 inet->rcv_saddr = inet->saddr;
91 inet->dport = usin->sin_port;
92 inet->daddr = daddr;
94 inet_csk(sk)->icsk_ext_hdr_len = 0;
95 if (inet->opt != NULL)
96 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
98 * Socket identity is still unknown (sport may be zero).
99 * However we set state to DCCP_REQUESTING and not releasing socket
100 * lock select source port, enter ourselves into the hash tables and
101 * complete initialization after this.
103 dccp_set_state(sk, DCCP_REQUESTING);
104 err = inet_hash_connect(&dccp_death_row, sk);
105 if (err != 0)
106 goto failure;
108 err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
109 sk);
110 if (err != 0)
111 goto failure;
113 /* OK, now commit destination to socket. */
114 sk_setup_caps(sk, &rt->u.dst);
116 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr, inet->daddr,
117 inet->sport, inet->dport);
118 inet->id = dp->dccps_iss ^ jiffies;
120 err = dccp_connect(sk);
121 rt = NULL;
122 if (err != 0)
123 goto failure;
124 out:
125 return err;
126 failure:
128 * This unhashes the socket and releases the local port, if necessary.
130 dccp_set_state(sk, DCCP_CLOSED);
131 ip_rt_put(rt);
132 sk->sk_route_caps = 0;
133 inet->dport = 0;
134 goto out;
137 EXPORT_SYMBOL_GPL(dccp_v4_connect);
140 * This routine does path mtu discovery as defined in RFC1191.
142 static inline void dccp_do_pmtu_discovery(struct sock *sk,
143 const struct iphdr *iph,
144 u32 mtu)
146 struct dst_entry *dst;
147 const struct inet_sock *inet = inet_sk(sk);
148 const struct dccp_sock *dp = dccp_sk(sk);
150 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
151 * send out by Linux are always < 576bytes so they should go through
152 * unfragmented).
154 if (sk->sk_state == DCCP_LISTEN)
155 return;
157 /* We don't check in the destentry if pmtu discovery is forbidden
158 * on this route. We just assume that no packet_to_big packets
159 * are send back when pmtu discovery is not active.
160 * There is a small race when the user changes this flag in the
161 * route, but I think that's acceptable.
163 if ((dst = __sk_dst_check(sk, 0)) == NULL)
164 return;
166 dst->ops->update_pmtu(dst, mtu);
168 /* Something is about to be wrong... Remember soft error
169 * for the case, if this connection will not able to recover.
171 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
172 sk->sk_err_soft = EMSGSIZE;
174 mtu = dst_mtu(dst);
176 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
177 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
178 dccp_sync_mss(sk, mtu);
181 * From RFC 4340, sec. 14.1:
183 * DCCP-Sync packets are the best choice for upward
184 * probing, since DCCP-Sync probes do not risk application
185 * data loss.
187 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
188 } /* else let the usual retransmit timer handle it */
192 * This routine is called by the ICMP module when it gets some sort of error
193 * condition. If err < 0 then the socket should be closed and the error
194 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
195 * After adjustment header points to the first 8 bytes of the tcp header. We
196 * need to find the appropriate port.
198 * The locking strategy used here is very "optimistic". When someone else
199 * accesses the socket the ICMP is just dropped and for some paths there is no
200 * check at all. A more general error queue to queue errors for later handling
201 * is probably better.
203 static void dccp_v4_err(struct sk_buff *skb, u32 info)
205 const struct iphdr *iph = (struct iphdr *)skb->data;
206 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
207 (iph->ihl << 2));
208 struct dccp_sock *dp;
209 struct inet_sock *inet;
210 const int type = skb->h.icmph->type;
211 const int code = skb->h.icmph->code;
212 struct sock *sk;
213 __u64 seq;
214 int err;
216 if (skb->len < (iph->ihl << 2) + 8) {
217 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
218 return;
221 sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
222 iph->saddr, dh->dccph_sport, inet_iif(skb));
223 if (sk == NULL) {
224 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
225 return;
228 if (sk->sk_state == DCCP_TIME_WAIT) {
229 inet_twsk_put(inet_twsk(sk));
230 return;
233 bh_lock_sock(sk);
234 /* If too many ICMPs get dropped on busy
235 * servers this needs to be solved differently.
237 if (sock_owned_by_user(sk))
238 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
240 if (sk->sk_state == DCCP_CLOSED)
241 goto out;
243 dp = dccp_sk(sk);
244 seq = dccp_hdr_seq(skb);
245 if (sk->sk_state != DCCP_LISTEN &&
246 !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
247 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
248 goto out;
251 switch (type) {
252 case ICMP_SOURCE_QUENCH:
253 /* Just silently ignore these. */
254 goto out;
255 case ICMP_PARAMETERPROB:
256 err = EPROTO;
257 break;
258 case ICMP_DEST_UNREACH:
259 if (code > NR_ICMP_UNREACH)
260 goto out;
262 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
263 if (!sock_owned_by_user(sk))
264 dccp_do_pmtu_discovery(sk, iph, info);
265 goto out;
268 err = icmp_err_convert[code].errno;
269 break;
270 case ICMP_TIME_EXCEEDED:
271 err = EHOSTUNREACH;
272 break;
273 default:
274 goto out;
277 switch (sk->sk_state) {
278 struct request_sock *req , **prev;
279 case DCCP_LISTEN:
280 if (sock_owned_by_user(sk))
281 goto out;
282 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
283 iph->daddr, iph->saddr);
284 if (!req)
285 goto out;
288 * ICMPs are not backlogged, hence we cannot get an established
289 * socket here.
291 BUG_TRAP(!req->sk);
293 if (seq != dccp_rsk(req)->dreq_iss) {
294 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
295 goto out;
298 * Still in RESPOND, just remove it silently.
299 * There is no good way to pass the error to the newly
300 * created socket, and POSIX does not want network
301 * errors returned from accept().
303 inet_csk_reqsk_queue_drop(sk, req, prev);
304 goto out;
306 case DCCP_REQUESTING:
307 case DCCP_RESPOND:
308 if (!sock_owned_by_user(sk)) {
309 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
310 sk->sk_err = err;
312 sk->sk_error_report(sk);
314 dccp_done(sk);
315 } else
316 sk->sk_err_soft = err;
317 goto out;
320 /* If we've already connected we will keep trying
321 * until we time out, or the user gives up.
323 * rfc1122 4.2.3.9 allows to consider as hard errors
324 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
325 * but it is obsoleted by pmtu discovery).
327 * Note, that in modern internet, where routing is unreliable
328 * and in each dark corner broken firewalls sit, sending random
329 * errors ordered by their masters even this two messages finally lose
330 * their original sense (even Linux sends invalid PORT_UNREACHs)
332 * Now we are in compliance with RFCs.
333 * --ANK (980905)
336 inet = inet_sk(sk);
337 if (!sock_owned_by_user(sk) && inet->recverr) {
338 sk->sk_err = err;
339 sk->sk_error_report(sk);
340 } else /* Only an error on timeout */
341 sk->sk_err_soft = err;
342 out:
343 bh_unlock_sock(sk);
344 sock_put(sk);
347 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
348 __be32 src, __be32 dst)
350 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
353 void dccp_v4_send_check(struct sock *sk, int unused, struct sk_buff *skb)
355 const struct inet_sock *inet = inet_sk(sk);
356 struct dccp_hdr *dh = dccp_hdr(skb);
358 dccp_csum_outgoing(skb);
359 dh->dccph_checksum = dccp_v4_csum_finish(skb, inet->saddr, inet->daddr);
362 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
364 static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
366 return secure_dccp_sequence_number(skb->nh.iph->daddr,
367 skb->nh.iph->saddr,
368 dccp_hdr(skb)->dccph_dport,
369 dccp_hdr(skb)->dccph_sport);
373 * The three way handshake has completed - we got a valid ACK or DATAACK -
374 * now create the new socket.
376 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
378 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
379 struct request_sock *req,
380 struct dst_entry *dst)
382 struct inet_request_sock *ireq;
383 struct inet_sock *newinet;
384 struct dccp_sock *newdp;
385 struct sock *newsk;
387 if (sk_acceptq_is_full(sk))
388 goto exit_overflow;
390 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
391 goto exit;
393 newsk = dccp_create_openreq_child(sk, req, skb);
394 if (newsk == NULL)
395 goto exit;
397 sk_setup_caps(newsk, dst);
399 newdp = dccp_sk(newsk);
400 newinet = inet_sk(newsk);
401 ireq = inet_rsk(req);
402 newinet->daddr = ireq->rmt_addr;
403 newinet->rcv_saddr = ireq->loc_addr;
404 newinet->saddr = ireq->loc_addr;
405 newinet->opt = ireq->opt;
406 ireq->opt = NULL;
407 newinet->mc_index = inet_iif(skb);
408 newinet->mc_ttl = skb->nh.iph->ttl;
409 newinet->id = jiffies;
411 dccp_sync_mss(newsk, dst_mtu(dst));
413 __inet_hash(&dccp_hashinfo, newsk, 0);
414 __inet_inherit_port(&dccp_hashinfo, sk, newsk);
416 return newsk;
418 exit_overflow:
419 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
420 exit:
421 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
422 dst_release(dst);
423 return NULL;
426 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
428 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
430 const struct dccp_hdr *dh = dccp_hdr(skb);
431 const struct iphdr *iph = skb->nh.iph;
432 struct sock *nsk;
433 struct request_sock **prev;
434 /* Find possible connection requests. */
435 struct request_sock *req = inet_csk_search_req(sk, &prev,
436 dh->dccph_sport,
437 iph->saddr, iph->daddr);
438 if (req != NULL)
439 return dccp_check_req(sk, skb, req, prev);
441 nsk = inet_lookup_established(&dccp_hashinfo,
442 iph->saddr, dh->dccph_sport,
443 iph->daddr, dh->dccph_dport,
444 inet_iif(skb));
445 if (nsk != NULL) {
446 if (nsk->sk_state != DCCP_TIME_WAIT) {
447 bh_lock_sock(nsk);
448 return nsk;
450 inet_twsk_put(inet_twsk(nsk));
451 return NULL;
454 return sk;
457 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
458 struct sk_buff *skb)
460 struct rtable *rt;
461 struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
462 .nl_u = { .ip4_u =
463 { .daddr = skb->nh.iph->saddr,
464 .saddr = skb->nh.iph->daddr,
465 .tos = RT_CONN_FLAGS(sk) } },
466 .proto = sk->sk_protocol,
467 .uli_u = { .ports =
468 { .sport = dccp_hdr(skb)->dccph_dport,
469 .dport = dccp_hdr(skb)->dccph_sport }
473 security_skb_classify_flow(skb, &fl);
474 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
475 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
476 return NULL;
479 return &rt->u.dst;
482 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
483 struct dst_entry *dst)
485 int err = -1;
486 struct sk_buff *skb;
488 /* First, grab a route. */
490 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
491 goto out;
493 skb = dccp_make_response(sk, dst, req);
494 if (skb != NULL) {
495 const struct inet_request_sock *ireq = inet_rsk(req);
496 struct dccp_hdr *dh = dccp_hdr(skb);
498 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
499 ireq->rmt_addr);
500 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
501 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
502 ireq->rmt_addr,
503 ireq->opt);
504 err = net_xmit_eval(err);
507 out:
508 dst_release(dst);
509 return err;
512 static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
514 int err;
515 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
516 const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
517 sizeof(struct dccp_hdr_ext) +
518 sizeof(struct dccp_hdr_reset);
519 struct sk_buff *skb;
520 struct dst_entry *dst;
521 u64 seqno = 0;
523 /* Never send a reset in response to a reset. */
524 if (rxdh->dccph_type == DCCP_PKT_RESET)
525 return;
527 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
528 return;
530 dst = dccp_v4_route_skb(dccp_v4_ctl_socket->sk, rxskb);
531 if (dst == NULL)
532 return;
534 skb = alloc_skb(dccp_v4_ctl_socket->sk->sk_prot->max_header,
535 GFP_ATOMIC);
536 if (skb == NULL)
537 goto out;
539 /* Reserve space for headers. */
540 skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header);
541 skb->dst = dst_clone(dst);
543 dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
545 /* Build DCCP header and checksum it. */
546 dh->dccph_type = DCCP_PKT_RESET;
547 dh->dccph_sport = rxdh->dccph_dport;
548 dh->dccph_dport = rxdh->dccph_sport;
549 dh->dccph_doff = dccp_hdr_reset_len / 4;
550 dh->dccph_x = 1;
551 dccp_hdr_reset(skb)->dccph_reset_code =
552 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
554 /* See "8.3.1. Abnormal Termination" in RFC 4340 */
555 if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
556 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
558 dccp_hdr_set_seq(dh, seqno);
559 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), DCCP_SKB_CB(rxskb)->dccpd_seq);
561 dccp_csum_outgoing(skb);
562 dh->dccph_checksum = dccp_v4_csum_finish(skb, rxskb->nh.iph->saddr,
563 rxskb->nh.iph->daddr);
565 bh_lock_sock(dccp_v4_ctl_socket->sk);
566 err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
567 rxskb->nh.iph->daddr,
568 rxskb->nh.iph->saddr, NULL);
569 bh_unlock_sock(dccp_v4_ctl_socket->sk);
571 if (net_xmit_eval(err) == 0) {
572 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
573 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
575 out:
576 dst_release(dst);
579 static void dccp_v4_reqsk_destructor(struct request_sock *req)
581 kfree(inet_rsk(req)->opt);
584 static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
585 .family = PF_INET,
586 .obj_size = sizeof(struct dccp_request_sock),
587 .rtx_syn_ack = dccp_v4_send_response,
588 .send_ack = dccp_reqsk_send_ack,
589 .destructor = dccp_v4_reqsk_destructor,
590 .send_reset = dccp_v4_ctl_send_reset,
593 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
595 struct inet_request_sock *ireq;
596 struct request_sock *req;
597 struct dccp_request_sock *dreq;
598 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
599 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
600 __u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
602 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
603 if (((struct rtable *)skb->dst)->rt_flags &
604 (RTCF_BROADCAST | RTCF_MULTICAST)) {
605 reset_code = DCCP_RESET_CODE_NO_CONNECTION;
606 goto drop;
609 if (dccp_bad_service_code(sk, service)) {
610 reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
611 goto drop;
614 * TW buckets are converted to open requests without
615 * limitations, they conserve resources and peer is
616 * evidently real one.
618 if (inet_csk_reqsk_queue_is_full(sk))
619 goto drop;
622 * Accept backlog is full. If we have already queued enough
623 * of warm entries in syn queue, drop request. It is better than
624 * clogging syn queue with openreqs with exponentially increasing
625 * timeout.
627 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
628 goto drop;
630 req = reqsk_alloc(&dccp_request_sock_ops);
631 if (req == NULL)
632 goto drop;
634 if (dccp_parse_options(sk, skb))
635 goto drop_and_free;
637 dccp_reqsk_init(req, skb);
639 if (security_inet_conn_request(sk, skb, req))
640 goto drop_and_free;
642 ireq = inet_rsk(req);
643 ireq->loc_addr = skb->nh.iph->daddr;
644 ireq->rmt_addr = skb->nh.iph->saddr;
645 ireq->opt = NULL;
648 * Step 3: Process LISTEN state
650 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
652 * In fact we defer setting S.GSR, S.SWL, S.SWH to
653 * dccp_create_openreq_child.
655 dreq = dccp_rsk(req);
656 dreq->dreq_isr = dcb->dccpd_seq;
657 dreq->dreq_iss = dccp_v4_init_sequence(skb);
658 dreq->dreq_service = service;
660 if (dccp_v4_send_response(sk, req, NULL))
661 goto drop_and_free;
663 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
664 return 0;
666 drop_and_free:
667 reqsk_free(req);
668 drop:
669 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
670 dcb->dccpd_reset_code = reset_code;
671 return -1;
674 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
676 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
678 struct dccp_hdr *dh = dccp_hdr(skb);
680 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
681 if (dccp_rcv_established(sk, skb, dh, skb->len))
682 goto reset;
683 return 0;
687 * Step 3: Process LISTEN state
688 * If P.type == Request or P contains a valid Init Cookie option,
689 * (* Must scan the packet's options to check for Init
690 * Cookies. Only Init Cookies are processed here,
691 * however; other options are processed in Step 8. This
692 * scan need only be performed if the endpoint uses Init
693 * Cookies *)
694 * (* Generate a new socket and switch to that socket *)
695 * Set S := new socket for this port pair
696 * S.state = RESPOND
697 * Choose S.ISS (initial seqno) or set from Init Cookies
698 * Initialize S.GAR := S.ISS
699 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
700 * Continue with S.state == RESPOND
701 * (* A Response packet will be generated in Step 11 *)
702 * Otherwise,
703 * Generate Reset(No Connection) unless P.type == Reset
704 * Drop packet and return
706 * NOTE: the check for the packet types is done in
707 * dccp_rcv_state_process
709 if (sk->sk_state == DCCP_LISTEN) {
710 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
712 if (nsk == NULL)
713 goto discard;
715 if (nsk != sk) {
716 if (dccp_child_process(sk, nsk, skb))
717 goto reset;
718 return 0;
722 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
723 goto reset;
724 return 0;
726 reset:
727 dccp_v4_ctl_send_reset(sk, skb);
728 discard:
729 kfree_skb(skb);
730 return 0;
733 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
736 * dccp_invalid_packet - check for malformed packets
737 * Implements RFC 4340, 8.5: Step 1: Check header basics
738 * Packets that fail these checks are ignored and do not receive Resets.
740 int dccp_invalid_packet(struct sk_buff *skb)
742 const struct dccp_hdr *dh;
743 unsigned int cscov;
745 if (skb->pkt_type != PACKET_HOST)
746 return 1;
748 /* If the packet is shorter than 12 bytes, drop packet and return */
749 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
750 DCCP_WARN("pskb_may_pull failed\n");
751 return 1;
754 dh = dccp_hdr(skb);
756 /* If P.type is not understood, drop packet and return */
757 if (dh->dccph_type >= DCCP_PKT_INVALID) {
758 DCCP_WARN("invalid packet type\n");
759 return 1;
763 * If P.Data Offset is too small for packet type, drop packet and return
765 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
766 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
767 return 1;
770 * If P.Data Offset is too too large for packet, drop packet and return
772 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
773 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
774 return 1;
778 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
779 * has short sequence numbers), drop packet and return
781 if (dh->dccph_type >= DCCP_PKT_DATA &&
782 dh->dccph_type <= DCCP_PKT_DATAACK && dh->dccph_x == 0) {
783 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
784 dccp_packet_name(dh->dccph_type));
785 return 1;
789 * If P.CsCov is too large for the packet size, drop packet and return.
790 * This must come _before_ checksumming (not as RFC 4340 suggests).
792 cscov = dccp_csum_coverage(skb);
793 if (cscov > skb->len) {
794 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
795 dh->dccph_cscov, skb->len);
796 return 1;
799 /* If header checksum is incorrect, drop packet and return.
800 * (This step is completed in the AF-dependent functions.) */
801 skb->csum = skb_checksum(skb, 0, cscov, 0);
803 return 0;
806 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
808 /* this is called when real data arrives */
809 static int dccp_v4_rcv(struct sk_buff *skb)
811 const struct dccp_hdr *dh;
812 struct sock *sk;
813 int min_cov;
815 /* Step 1: Check header basics */
817 if (dccp_invalid_packet(skb))
818 goto discard_it;
820 /* Step 1: If header checksum is incorrect, drop packet and return */
821 if (dccp_v4_csum_finish(skb, skb->nh.iph->saddr, skb->nh.iph->daddr)) {
822 DCCP_WARN("dropped packet with invalid checksum\n");
823 goto discard_it;
826 dh = dccp_hdr(skb);
828 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
829 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
831 dccp_pr_debug("%8.8s "
832 "src=%u.%u.%u.%u@%-5d "
833 "dst=%u.%u.%u.%u@%-5d seq=%llu",
834 dccp_packet_name(dh->dccph_type),
835 NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
836 NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
837 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
839 if (dccp_packet_without_ack(skb)) {
840 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
841 dccp_pr_debug_cat("\n");
842 } else {
843 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
844 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
845 DCCP_SKB_CB(skb)->dccpd_ack_seq);
848 /* Step 2:
849 * Look up flow ID in table and get corresponding socket */
850 sk = __inet_lookup(&dccp_hashinfo,
851 skb->nh.iph->saddr, dh->dccph_sport,
852 skb->nh.iph->daddr, dh->dccph_dport,
853 inet_iif(skb));
856 * Step 2:
857 * If no socket ...
859 if (sk == NULL) {
860 dccp_pr_debug("failed to look up flow ID in table and "
861 "get corresponding socket\n");
862 goto no_dccp_socket;
866 * Step 2:
867 * ... or S.state == TIMEWAIT,
868 * Generate Reset(No Connection) unless P.type == Reset
869 * Drop packet and return
871 if (sk->sk_state == DCCP_TIME_WAIT) {
872 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
873 inet_twsk_put(inet_twsk(sk));
874 goto no_dccp_socket;
878 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
879 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
880 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
882 min_cov = dccp_sk(sk)->dccps_pcrlen;
883 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
884 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
885 dh->dccph_cscov, min_cov);
886 /* FIXME: "Such packets SHOULD be reported using Data Dropped
887 * options (Section 11.7) with Drop Code 0, Protocol
888 * Constraints." */
889 goto discard_and_relse;
892 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
893 goto discard_and_relse;
894 nf_reset(skb);
896 return sk_receive_skb(sk, skb, 1);
898 no_dccp_socket:
899 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
900 goto discard_it;
902 * Step 2:
903 * If no socket ...
904 * Generate Reset(No Connection) unless P.type == Reset
905 * Drop packet and return
907 if (dh->dccph_type != DCCP_PKT_RESET) {
908 DCCP_SKB_CB(skb)->dccpd_reset_code =
909 DCCP_RESET_CODE_NO_CONNECTION;
910 dccp_v4_ctl_send_reset(sk, skb);
913 discard_it:
914 kfree_skb(skb);
915 return 0;
917 discard_and_relse:
918 sock_put(sk);
919 goto discard_it;
922 static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
923 .queue_xmit = ip_queue_xmit,
924 .send_check = dccp_v4_send_check,
925 .rebuild_header = inet_sk_rebuild_header,
926 .conn_request = dccp_v4_conn_request,
927 .syn_recv_sock = dccp_v4_request_recv_sock,
928 .net_header_len = sizeof(struct iphdr),
929 .setsockopt = ip_setsockopt,
930 .getsockopt = ip_getsockopt,
931 .addr2sockaddr = inet_csk_addr2sockaddr,
932 .sockaddr_len = sizeof(struct sockaddr_in),
933 #ifdef CONFIG_COMPAT
934 .compat_setsockopt = compat_ip_setsockopt,
935 .compat_getsockopt = compat_ip_getsockopt,
936 #endif
939 static int dccp_v4_init_sock(struct sock *sk)
941 static __u8 dccp_v4_ctl_sock_initialized;
942 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
944 if (err == 0) {
945 if (unlikely(!dccp_v4_ctl_sock_initialized))
946 dccp_v4_ctl_sock_initialized = 1;
947 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
950 return err;
953 static struct timewait_sock_ops dccp_timewait_sock_ops = {
954 .twsk_obj_size = sizeof(struct inet_timewait_sock),
957 static struct proto dccp_v4_prot = {
958 .name = "DCCP",
959 .owner = THIS_MODULE,
960 .close = dccp_close,
961 .connect = dccp_v4_connect,
962 .disconnect = dccp_disconnect,
963 .ioctl = dccp_ioctl,
964 .init = dccp_v4_init_sock,
965 .setsockopt = dccp_setsockopt,
966 .getsockopt = dccp_getsockopt,
967 .sendmsg = dccp_sendmsg,
968 .recvmsg = dccp_recvmsg,
969 .backlog_rcv = dccp_v4_do_rcv,
970 .hash = dccp_hash,
971 .unhash = dccp_unhash,
972 .accept = inet_csk_accept,
973 .get_port = dccp_v4_get_port,
974 .shutdown = dccp_shutdown,
975 .destroy = dccp_destroy_sock,
976 .orphan_count = &dccp_orphan_count,
977 .max_header = MAX_DCCP_HEADER,
978 .obj_size = sizeof(struct dccp_sock),
979 .rsk_prot = &dccp_request_sock_ops,
980 .twsk_prot = &dccp_timewait_sock_ops,
981 #ifdef CONFIG_COMPAT
982 .compat_setsockopt = compat_dccp_setsockopt,
983 .compat_getsockopt = compat_dccp_getsockopt,
984 #endif
987 static struct net_protocol dccp_v4_protocol = {
988 .handler = dccp_v4_rcv,
989 .err_handler = dccp_v4_err,
990 .no_policy = 1,
993 static const struct proto_ops inet_dccp_ops = {
994 .family = PF_INET,
995 .owner = THIS_MODULE,
996 .release = inet_release,
997 .bind = inet_bind,
998 .connect = inet_stream_connect,
999 .socketpair = sock_no_socketpair,
1000 .accept = inet_accept,
1001 .getname = inet_getname,
1002 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1003 .poll = dccp_poll,
1004 .ioctl = inet_ioctl,
1005 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1006 .listen = inet_dccp_listen,
1007 .shutdown = inet_shutdown,
1008 .setsockopt = sock_common_setsockopt,
1009 .getsockopt = sock_common_getsockopt,
1010 .sendmsg = inet_sendmsg,
1011 .recvmsg = sock_common_recvmsg,
1012 .mmap = sock_no_mmap,
1013 .sendpage = sock_no_sendpage,
1014 #ifdef CONFIG_COMPAT
1015 .compat_setsockopt = compat_sock_common_setsockopt,
1016 .compat_getsockopt = compat_sock_common_getsockopt,
1017 #endif
1020 static struct inet_protosw dccp_v4_protosw = {
1021 .type = SOCK_DCCP,
1022 .protocol = IPPROTO_DCCP,
1023 .prot = &dccp_v4_prot,
1024 .ops = &inet_dccp_ops,
1025 .capability = -1,
1026 .no_check = 0,
1027 .flags = INET_PROTOSW_ICSK,
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 = inet_csk_ctl_sock_create(&dccp_v4_ctl_socket, PF_INET,
1044 SOCK_DCCP, IPPROTO_DCCP);
1045 if (err)
1046 goto out_unregister_protosw;
1047 out:
1048 return err;
1049 out_unregister_protosw:
1050 inet_unregister_protosw(&dccp_v4_protosw);
1051 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1052 out_proto_unregister:
1053 proto_unregister(&dccp_v4_prot);
1054 goto out;
1057 static void __exit dccp_v4_exit(void)
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-" __stringify(PF_INET) "-proto-33-type-6");
1073 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-0-type-6");
1074 MODULE_LICENSE("GPL");
1075 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1076 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");