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/config.h>
14 #include <linux/dccp.h>
15 #include <linux/icmp.h>
16 #include <linux/module.h>
17 #include <linux/skbuff.h>
18 #include <linux/random.h>
21 #include <net/inet_common.h>
22 #include <net/inet_hashtables.h>
23 #include <net/inet_sock.h>
24 #include <net/protocol.h>
26 #include <net/timewait_sock.h>
27 #include <net/tcp_states.h>
36 * This is the global socket data structure 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.
40 static struct socket *dccp_v4_ctl_socket;
42 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
44 return inet_csk_get_port(&dccp_hashinfo, sk, snum,
45 inet_csk_bind_conflict);
48 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
50 struct inet_sock *inet = inet_sk(sk);
51 struct dccp_sock *dp = dccp_sk(sk);
52 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
58 dp->dccps_role = DCCP_ROLE_CLIENT;
60 if (dccp_service_not_initialized(sk))
63 if (addr_len < sizeof(struct sockaddr_in))
66 if (usin->sin_family != AF_INET)
69 nexthop = daddr = usin->sin_addr.s_addr;
70 if (inet->opt != NULL && inet->opt->srr) {
73 nexthop = inet->opt->faddr;
76 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
77 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
79 inet->sport, usin->sin_port, sk);
83 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
88 if (inet->opt == NULL || !inet->opt->srr)
92 inet->saddr = rt->rt_src;
93 inet->rcv_saddr = inet->saddr;
95 inet->dport = usin->sin_port;
98 inet_csk(sk)->icsk_ext_hdr_len = 0;
99 if (inet->opt != NULL)
100 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
102 * Socket identity is still unknown (sport may be zero).
103 * However we set state to DCCP_REQUESTING and not releasing socket
104 * lock select source port, enter ourselves into the hash tables and
105 * complete initialization after this.
107 dccp_set_state(sk, DCCP_REQUESTING);
108 err = inet_hash_connect(&dccp_death_row, sk);
112 err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
117 /* OK, now commit destination to socket. */
118 sk_setup_caps(sk, &rt->u.dst);
121 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
125 dccp_update_gss(sk, dp->dccps_iss);
127 inet->id = dp->dccps_iss ^ jiffies;
129 err = dccp_connect(sk);
137 * This unhashes the socket and releases the local port, if necessary.
139 dccp_set_state(sk, DCCP_CLOSED);
141 sk->sk_route_caps = 0;
146 EXPORT_SYMBOL_GPL(dccp_v4_connect);
149 * This routine does path mtu discovery as defined in RFC1191.
151 static inline void dccp_do_pmtu_discovery(struct sock *sk,
152 const struct iphdr *iph,
155 struct dst_entry *dst;
156 const struct inet_sock *inet = inet_sk(sk);
157 const struct dccp_sock *dp = dccp_sk(sk);
159 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
160 * send out by Linux are always < 576bytes so they should go through
163 if (sk->sk_state == DCCP_LISTEN)
166 /* We don't check in the destentry if pmtu discovery is forbidden
167 * on this route. We just assume that no packet_to_big packets
168 * are send back when pmtu discovery is not active.
169 * There is a small race when the user changes this flag in the
170 * route, but I think that's acceptable.
172 if ((dst = __sk_dst_check(sk, 0)) == NULL)
175 dst->ops->update_pmtu(dst, mtu);
177 /* Something is about to be wrong... Remember soft error
178 * for the case, if this connection will not able to recover.
180 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
181 sk->sk_err_soft = EMSGSIZE;
185 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
186 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
187 dccp_sync_mss(sk, mtu);
190 * From: draft-ietf-dccp-spec-11.txt
192 * DCCP-Sync packets are the best choice for upward
193 * probing, since DCCP-Sync probes do not risk application
196 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
197 } /* else let the usual retransmit timer handle it */
200 static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
203 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
204 const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
205 sizeof(struct dccp_hdr_ext) +
206 sizeof(struct dccp_hdr_ack_bits);
209 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
212 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
216 /* Reserve space for headers. */
217 skb_reserve(skb, MAX_DCCP_HEADER);
219 skb->dst = dst_clone(rxskb->dst);
221 skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
223 memset(dh, 0, dccp_hdr_ack_len);
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;
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);
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);
242 if (err == NET_XMIT_CN || err == 0) {
243 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
244 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
248 static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
249 struct request_sock *req)
251 dccp_v4_ctl_send_ack(skb);
254 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
255 struct dst_entry *dst)
260 /* First, grab a route. */
262 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
265 skb = dccp_make_response(sk, dst, req);
267 const struct inet_request_sock *ireq = inet_rsk(req);
268 struct dccp_hdr *dh = dccp_hdr(skb);
270 dh->dccph_checksum = dccp_v4_checksum(skb, ireq->loc_addr,
272 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
273 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
276 if (err == NET_XMIT_CN)
286 * This routine is called by the ICMP module when it gets some sort of error
287 * condition. If err < 0 then the socket should be closed and the error
288 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
289 * After adjustment header points to the first 8 bytes of the tcp header. We
290 * need to find the appropriate port.
292 * The locking strategy used here is very "optimistic". When someone else
293 * accesses the socket the ICMP is just dropped and for some paths there is no
294 * check at all. A more general error queue to queue errors for later handling
295 * is probably better.
297 static void dccp_v4_err(struct sk_buff *skb, u32 info)
299 const struct iphdr *iph = (struct iphdr *)skb->data;
300 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
302 struct dccp_sock *dp;
303 struct inet_sock *inet;
304 const int type = skb->h.icmph->type;
305 const int code = skb->h.icmph->code;
310 if (skb->len < (iph->ihl << 2) + 8) {
311 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
315 sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
316 iph->saddr, dh->dccph_sport, inet_iif(skb));
318 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
322 if (sk->sk_state == DCCP_TIME_WAIT) {
323 inet_twsk_put((struct inet_timewait_sock *)sk);
328 /* If too many ICMPs get dropped on busy
329 * servers this needs to be solved differently.
331 if (sock_owned_by_user(sk))
332 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
334 if (sk->sk_state == DCCP_CLOSED)
338 seq = dccp_hdr_seq(skb);
339 if (sk->sk_state != DCCP_LISTEN &&
340 !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
341 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
346 case ICMP_SOURCE_QUENCH:
347 /* Just silently ignore these. */
349 case ICMP_PARAMETERPROB:
352 case ICMP_DEST_UNREACH:
353 if (code > NR_ICMP_UNREACH)
356 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
357 if (!sock_owned_by_user(sk))
358 dccp_do_pmtu_discovery(sk, iph, info);
362 err = icmp_err_convert[code].errno;
364 case ICMP_TIME_EXCEEDED:
371 switch (sk->sk_state) {
372 struct request_sock *req , **prev;
374 if (sock_owned_by_user(sk))
376 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
377 iph->daddr, iph->saddr);
382 * ICMPs are not backlogged, hence we cannot get an established
387 if (seq != dccp_rsk(req)->dreq_iss) {
388 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
392 * Still in RESPOND, just remove it silently.
393 * There is no good way to pass the error to the newly
394 * created socket, and POSIX does not want network
395 * errors returned from accept().
397 inet_csk_reqsk_queue_drop(sk, req, prev);
400 case DCCP_REQUESTING:
402 if (!sock_owned_by_user(sk)) {
403 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
406 sk->sk_error_report(sk);
410 sk->sk_err_soft = err;
414 /* If we've already connected we will keep trying
415 * until we time out, or the user gives up.
417 * rfc1122 4.2.3.9 allows to consider as hard errors
418 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
419 * but it is obsoleted by pmtu discovery).
421 * Note, that in modern internet, where routing is unreliable
422 * and in each dark corner broken firewalls sit, sending random
423 * errors ordered by their masters even this two messages finally lose
424 * their original sense (even Linux sends invalid PORT_UNREACHs)
426 * Now we are in compliance with RFCs.
431 if (!sock_owned_by_user(sk) && inet->recverr) {
433 sk->sk_error_report(sk);
434 } else /* Only an error on timeout */
435 sk->sk_err_soft = err;
441 /* This routine computes an IPv4 DCCP checksum. */
442 void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
444 const struct inet_sock *inet = inet_sk(sk);
445 struct dccp_hdr *dh = dccp_hdr(skb);
447 dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr, inet->daddr);
450 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
452 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
453 const struct sk_buff *skb)
455 return secure_dccp_sequence_number(skb->nh.iph->daddr,
457 dccp_hdr(skb)->dccph_dport,
458 dccp_hdr(skb)->dccph_sport);
461 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
463 struct inet_request_sock *ireq;
465 struct request_sock *req;
466 struct dccp_request_sock *dreq;
467 const __be32 saddr = skb->nh.iph->saddr;
468 const __be32 daddr = skb->nh.iph->daddr;
469 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
470 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
471 __u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
473 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
474 if (((struct rtable *)skb->dst)->rt_flags &
475 (RTCF_BROADCAST | RTCF_MULTICAST)) {
476 reset_code = DCCP_RESET_CODE_NO_CONNECTION;
480 if (dccp_bad_service_code(sk, service)) {
481 reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
485 * TW buckets are converted to open requests without
486 * limitations, they conserve resources and peer is
487 * evidently real one.
489 if (inet_csk_reqsk_queue_is_full(sk))
493 * Accept backlog is full. If we have already queued enough
494 * of warm entries in syn queue, drop request. It is better than
495 * clogging syn queue with openreqs with exponentially increasing
498 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
501 req = reqsk_alloc(sk->sk_prot->rsk_prot);
505 if (dccp_parse_options(sk, skb))
508 dccp_openreq_init(req, &dp, skb);
510 ireq = inet_rsk(req);
511 ireq->loc_addr = daddr;
512 ireq->rmt_addr = saddr;
513 req->rcv_wnd = 100; /* Fake, option parsing will get the
518 * Step 3: Process LISTEN state
520 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
522 * In fact we defer setting S.GSR, S.SWL, S.SWH to
523 * dccp_create_openreq_child.
525 dreq = dccp_rsk(req);
526 dreq->dreq_isr = dcb->dccpd_seq;
527 dreq->dreq_iss = dccp_v4_init_sequence(sk, skb);
528 dreq->dreq_service = service;
530 if (dccp_v4_send_response(sk, req, NULL))
533 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
539 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
540 dcb->dccpd_reset_code = reset_code;
544 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
547 * The three way handshake has completed - we got a valid ACK or DATAACK -
548 * now create the new socket.
550 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
552 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
553 struct request_sock *req,
554 struct dst_entry *dst)
556 struct inet_request_sock *ireq;
557 struct inet_sock *newinet;
558 struct dccp_sock *newdp;
561 if (sk_acceptq_is_full(sk))
564 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
567 newsk = dccp_create_openreq_child(sk, req, skb);
571 sk_setup_caps(newsk, dst);
573 newdp = dccp_sk(newsk);
574 newinet = inet_sk(newsk);
575 ireq = inet_rsk(req);
576 newinet->daddr = ireq->rmt_addr;
577 newinet->rcv_saddr = ireq->loc_addr;
578 newinet->saddr = ireq->loc_addr;
579 newinet->opt = ireq->opt;
581 newinet->mc_index = inet_iif(skb);
582 newinet->mc_ttl = skb->nh.iph->ttl;
583 newinet->id = jiffies;
585 dccp_sync_mss(newsk, dst_mtu(dst));
587 __inet_hash(&dccp_hashinfo, newsk, 0);
588 __inet_inherit_port(&dccp_hashinfo, sk, newsk);
593 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
595 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
600 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
602 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
604 const struct dccp_hdr *dh = dccp_hdr(skb);
605 const struct iphdr *iph = skb->nh.iph;
607 struct request_sock **prev;
608 /* Find possible connection requests. */
609 struct request_sock *req = inet_csk_search_req(sk, &prev,
611 iph->saddr, iph->daddr);
613 return dccp_check_req(sk, skb, req, prev);
615 nsk = __inet_lookup_established(&dccp_hashinfo,
616 iph->saddr, dh->dccph_sport,
617 iph->daddr, ntohs(dh->dccph_dport),
620 if (nsk->sk_state != DCCP_TIME_WAIT) {
624 inet_twsk_put((struct inet_timewait_sock *)nsk);
631 int dccp_v4_checksum(const struct sk_buff *skb, const __be32 saddr,
634 const struct dccp_hdr* dh = dccp_hdr(skb);
638 if (dh->dccph_cscov == 0)
639 checksum_len = skb->len;
641 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
642 checksum_len = checksum_len < skb->len ? checksum_len :
646 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
647 return csum_tcpudp_magic(saddr, daddr, checksum_len,
651 EXPORT_SYMBOL_GPL(dccp_v4_checksum);
653 static int dccp_v4_verify_checksum(struct sk_buff *skb,
654 const __be32 saddr, const __be32 daddr)
656 struct dccp_hdr *dh = dccp_hdr(skb);
660 if (dh->dccph_cscov == 0)
661 checksum_len = skb->len;
663 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
664 checksum_len = checksum_len < skb->len ? checksum_len :
667 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
668 return csum_tcpudp_magic(saddr, daddr, checksum_len,
669 IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
672 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
676 struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
678 { .daddr = skb->nh.iph->saddr,
679 .saddr = skb->nh.iph->daddr,
680 .tos = RT_CONN_FLAGS(sk) } },
681 .proto = sk->sk_protocol,
683 { .sport = dccp_hdr(skb)->dccph_dport,
684 .dport = dccp_hdr(skb)->dccph_sport }
688 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
689 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
696 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
699 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
700 const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
701 sizeof(struct dccp_hdr_ext) +
702 sizeof(struct dccp_hdr_reset);
704 struct dst_entry *dst;
707 /* Never send a reset in response to a reset. */
708 if (rxdh->dccph_type == DCCP_PKT_RESET)
711 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
714 dst = dccp_v4_route_skb(dccp_v4_ctl_socket->sk, rxskb);
718 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
722 /* Reserve space for headers. */
723 skb_reserve(skb, MAX_DCCP_HEADER);
724 skb->dst = dst_clone(dst);
726 skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
728 memset(dh, 0, dccp_hdr_reset_len);
730 /* Build DCCP header and checksum it. */
731 dh->dccph_type = DCCP_PKT_RESET;
732 dh->dccph_sport = rxdh->dccph_dport;
733 dh->dccph_dport = rxdh->dccph_sport;
734 dh->dccph_doff = dccp_hdr_reset_len / 4;
736 dccp_hdr_reset(skb)->dccph_reset_code =
737 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
739 /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
741 if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
742 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
744 dccp_hdr_set_seq(dh, seqno);
745 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
746 DCCP_SKB_CB(rxskb)->dccpd_seq);
748 dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
749 rxskb->nh.iph->daddr);
751 bh_lock_sock(dccp_v4_ctl_socket->sk);
752 err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
753 rxskb->nh.iph->daddr,
754 rxskb->nh.iph->saddr, NULL);
755 bh_unlock_sock(dccp_v4_ctl_socket->sk);
757 if (err == NET_XMIT_CN || err == 0) {
758 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
759 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
765 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
767 struct dccp_hdr *dh = dccp_hdr(skb);
769 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
770 if (dccp_rcv_established(sk, skb, dh, skb->len))
776 * Step 3: Process LISTEN state
777 * If S.state == LISTEN,
778 * If P.type == Request or P contains a valid Init Cookie
780 * * Must scan the packet's options to check for an Init
781 * Cookie. Only the Init Cookie is processed here,
782 * however; other options are processed in Step 8. This
783 * scan need only be performed if the endpoint uses Init
785 * * Generate a new socket and switch to that socket *
786 * Set S := new socket for this port pair
788 * Choose S.ISS (initial seqno) or set from Init Cookie
789 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
790 * Continue with S.state == RESPOND
791 * * A Response packet will be generated in Step 11 *
793 * Generate Reset(No Connection) unless P.type == Reset
794 * Drop packet and return
796 * NOTE: the check for the packet types is done in
797 * dccp_rcv_state_process
799 if (sk->sk_state == DCCP_LISTEN) {
800 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
806 if (dccp_child_process(sk, nsk, skb))
812 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
817 dccp_v4_ctl_send_reset(skb);
823 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
825 int dccp_invalid_packet(struct sk_buff *skb)
827 const struct dccp_hdr *dh;
829 if (skb->pkt_type != PACKET_HOST)
832 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
833 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
839 /* If the packet type is not understood, drop packet and return */
840 if (dh->dccph_type >= DCCP_PKT_INVALID) {
841 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
846 * If P.Data Offset is too small for packet type, or too large for
847 * packet, drop packet and return
849 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
850 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
856 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
857 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
866 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
867 * has short sequence numbers), drop packet and return
869 if (dh->dccph_x == 0 &&
870 dh->dccph_type != DCCP_PKT_DATA &&
871 dh->dccph_type != DCCP_PKT_ACK &&
872 dh->dccph_type != DCCP_PKT_DATAACK) {
873 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
874 "nor DataAck and P.X == 0\n",
875 dccp_packet_name(dh->dccph_type));
882 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
884 /* this is called when real data arrives */
885 static int dccp_v4_rcv(struct sk_buff *skb)
887 const struct dccp_hdr *dh;
890 /* Step 1: Check header basics: */
892 if (dccp_invalid_packet(skb))
895 /* If the header checksum is incorrect, drop packet and return */
896 if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
897 skb->nh.iph->daddr) < 0) {
898 LIMIT_NETDEBUG(KERN_WARNING "%s: incorrect header checksum\n",
905 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
906 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
908 dccp_pr_debug("%8.8s "
909 "src=%u.%u.%u.%u@%-5d "
910 "dst=%u.%u.%u.%u@%-5d seq=%llu",
911 dccp_packet_name(dh->dccph_type),
912 NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
913 NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
914 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
916 if (dccp_packet_without_ack(skb)) {
917 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
918 dccp_pr_debug_cat("\n");
920 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
921 dccp_pr_debug_cat(", ack=%llu\n",
923 DCCP_SKB_CB(skb)->dccpd_ack_seq);
927 * Look up flow ID in table and get corresponding socket */
928 sk = __inet_lookup(&dccp_hashinfo,
929 skb->nh.iph->saddr, dh->dccph_sport,
930 skb->nh.iph->daddr, ntohs(dh->dccph_dport),
936 * Generate Reset(No Connection) unless P.type == Reset
937 * Drop packet and return
940 dccp_pr_debug("failed to look up flow ID in table and "
941 "get corresponding socket\n");
947 * ... or S.state == TIMEWAIT,
948 * Generate Reset(No Connection) unless P.type == Reset
949 * Drop packet and return
952 if (sk->sk_state == DCCP_TIME_WAIT) {
953 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
958 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
959 goto discard_and_relse;
962 return sk_receive_skb(sk, skb);
965 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
969 * Generate Reset(No Connection) unless P.type == Reset
970 * Drop packet and return
972 if (dh->dccph_type != DCCP_PKT_RESET) {
973 DCCP_SKB_CB(skb)->dccpd_reset_code =
974 DCCP_RESET_CODE_NO_CONNECTION;
975 dccp_v4_ctl_send_reset(skb);
988 inet_twsk_put((struct inet_timewait_sock *)sk);
992 static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
993 .queue_xmit = ip_queue_xmit,
994 .send_check = dccp_v4_send_check,
995 .rebuild_header = inet_sk_rebuild_header,
996 .conn_request = dccp_v4_conn_request,
997 .syn_recv_sock = dccp_v4_request_recv_sock,
998 .net_header_len = sizeof(struct iphdr),
999 .setsockopt = ip_setsockopt,
1000 .getsockopt = ip_getsockopt,
1001 .addr2sockaddr = inet_csk_addr2sockaddr,
1002 .sockaddr_len = sizeof(struct sockaddr_in),
1005 static int dccp_v4_init_sock(struct sock *sk)
1007 static __u8 dccp_v4_ctl_sock_initialized;
1008 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
1011 if (unlikely(!dccp_v4_ctl_sock_initialized))
1012 dccp_v4_ctl_sock_initialized = 1;
1013 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
1019 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1021 kfree(inet_rsk(req)->opt);
1024 static struct request_sock_ops dccp_request_sock_ops = {
1026 .obj_size = sizeof(struct dccp_request_sock),
1027 .rtx_syn_ack = dccp_v4_send_response,
1028 .send_ack = dccp_v4_reqsk_send_ack,
1029 .destructor = dccp_v4_reqsk_destructor,
1030 .send_reset = dccp_v4_ctl_send_reset,
1033 static struct timewait_sock_ops dccp_timewait_sock_ops = {
1034 .twsk_obj_size = sizeof(struct inet_timewait_sock),
1037 static struct proto dccp_v4_prot = {
1039 .owner = THIS_MODULE,
1040 .close = dccp_close,
1041 .connect = dccp_v4_connect,
1042 .disconnect = dccp_disconnect,
1043 .ioctl = dccp_ioctl,
1044 .init = dccp_v4_init_sock,
1045 .setsockopt = dccp_setsockopt,
1046 .getsockopt = dccp_getsockopt,
1047 .sendmsg = dccp_sendmsg,
1048 .recvmsg = dccp_recvmsg,
1049 .backlog_rcv = dccp_v4_do_rcv,
1051 .unhash = dccp_unhash,
1052 .accept = inet_csk_accept,
1053 .get_port = dccp_v4_get_port,
1054 .shutdown = dccp_shutdown,
1055 .destroy = dccp_destroy_sock,
1056 .orphan_count = &dccp_orphan_count,
1057 .max_header = MAX_DCCP_HEADER,
1058 .obj_size = sizeof(struct dccp_sock),
1059 .rsk_prot = &dccp_request_sock_ops,
1060 .twsk_prot = &dccp_timewait_sock_ops,
1063 static struct net_protocol dccp_v4_protocol = {
1064 .handler = dccp_v4_rcv,
1065 .err_handler = dccp_v4_err,
1069 static const struct proto_ops inet_dccp_ops = {
1071 .owner = THIS_MODULE,
1072 .release = inet_release,
1074 .connect = inet_stream_connect,
1075 .socketpair = sock_no_socketpair,
1076 .accept = inet_accept,
1077 .getname = inet_getname,
1078 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1080 .ioctl = inet_ioctl,
1081 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1082 .listen = inet_dccp_listen,
1083 .shutdown = inet_shutdown,
1084 .setsockopt = sock_common_setsockopt,
1085 .getsockopt = sock_common_getsockopt,
1086 .sendmsg = inet_sendmsg,
1087 .recvmsg = sock_common_recvmsg,
1088 .mmap = sock_no_mmap,
1089 .sendpage = sock_no_sendpage,
1092 static struct inet_protosw dccp_v4_protosw = {
1094 .protocol = IPPROTO_DCCP,
1095 .prot = &dccp_v4_prot,
1096 .ops = &inet_dccp_ops,
1099 .flags = INET_PROTOSW_ICSK,
1102 static char dccp_v4_ctl_socket_err_msg[] __initdata =
1103 KERN_ERR "DCCP: Failed to create the control socket.\n";
1105 static int __init dccp_v4_ctl_sock_init(void)
1107 int rc = sock_create_kern(PF_INET, SOCK_DCCP, IPPROTO_DCCP,
1108 &dccp_v4_ctl_socket);
1110 printk(dccp_v4_ctl_socket_err_msg);
1112 dccp_v4_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
1113 inet_sk(dccp_v4_ctl_socket->sk)->uc_ttl = -1;
1115 /* Unhash it so that IP input processing does not even
1116 * see it, we do not wish this socket to see incoming
1119 dccp_v4_ctl_socket->sk->sk_prot->unhash(dccp_v4_ctl_socket->sk);
1125 static int __init dccp_v4_init(void)
1127 int err = proto_register(&dccp_v4_prot, 1);
1132 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1134 goto out_proto_unregister;
1136 inet_register_protosw(&dccp_v4_protosw);
1138 err = dccp_v4_ctl_sock_init();
1140 goto out_unregister_protosw;
1143 out_unregister_protosw:
1144 inet_unregister_protosw(&dccp_v4_protosw);
1145 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1146 out_proto_unregister:
1147 proto_unregister(&dccp_v4_prot);
1151 static void __exit dccp_v4_exit(void)
1153 inet_unregister_protosw(&dccp_v4_protosw);
1154 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1155 proto_unregister(&dccp_v4_prot);
1158 module_init(dccp_v4_init);
1159 module_exit(dccp_v4_exit);
1162 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1163 * values directly, Also cover the case where the protocol is not specified,
1164 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1166 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-33-type-6");
1167 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-0-type-6");
1168 MODULE_LICENSE("GPL");
1169 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1170 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");