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>
35 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
37 return inet_csk_get_port(&dccp_hashinfo, sk, snum,
38 inet_csk_bind_conflict);
41 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
43 struct inet_sock *inet = inet_sk(sk);
44 struct dccp_sock *dp = dccp_sk(sk);
45 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
51 dp->dccps_role = DCCP_ROLE_CLIENT;
53 if (dccp_service_not_initialized(sk))
56 if (addr_len < sizeof(struct sockaddr_in))
59 if (usin->sin_family != AF_INET)
62 nexthop = daddr = usin->sin_addr.s_addr;
63 if (inet->opt != NULL && inet->opt->srr) {
66 nexthop = inet->opt->faddr;
69 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
70 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
72 inet->sport, usin->sin_port, sk);
76 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
81 if (inet->opt == NULL || !inet->opt->srr)
85 inet->saddr = rt->rt_src;
86 inet->rcv_saddr = inet->saddr;
88 inet->dport = usin->sin_port;
91 inet_csk(sk)->icsk_ext_hdr_len = 0;
92 if (inet->opt != NULL)
93 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
95 * Socket identity is still unknown (sport may be zero).
96 * However we set state to DCCP_REQUESTING and not releasing socket
97 * lock select source port, enter ourselves into the hash tables and
98 * complete initialization after this.
100 dccp_set_state(sk, DCCP_REQUESTING);
101 err = inet_hash_connect(&dccp_death_row, sk);
105 err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
110 /* OK, now commit destination to socket. */
111 sk_setup_caps(sk, &rt->u.dst);
114 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
118 dccp_update_gss(sk, dp->dccps_iss);
120 inet->id = dp->dccps_iss ^ jiffies;
122 err = dccp_connect(sk);
130 * This unhashes the socket and releases the local port, if necessary.
132 dccp_set_state(sk, DCCP_CLOSED);
134 sk->sk_route_caps = 0;
139 EXPORT_SYMBOL_GPL(dccp_v4_connect);
142 * This routine does path mtu discovery as defined in RFC1191.
144 static inline void dccp_do_pmtu_discovery(struct sock *sk,
145 const struct iphdr *iph,
148 struct dst_entry *dst;
149 const struct inet_sock *inet = inet_sk(sk);
150 const struct dccp_sock *dp = dccp_sk(sk);
152 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
153 * send out by Linux are always < 576bytes so they should go through
156 if (sk->sk_state == DCCP_LISTEN)
159 /* We don't check in the destentry if pmtu discovery is forbidden
160 * on this route. We just assume that no packet_to_big packets
161 * are send back when pmtu discovery is not active.
162 * There is a small race when the user changes this flag in the
163 * route, but I think that's acceptable.
165 if ((dst = __sk_dst_check(sk, 0)) == NULL)
168 dst->ops->update_pmtu(dst, mtu);
170 /* Something is about to be wrong... Remember soft error
171 * for the case, if this connection will not able to recover.
173 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
174 sk->sk_err_soft = EMSGSIZE;
178 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
179 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
180 dccp_sync_mss(sk, mtu);
183 * From: draft-ietf-dccp-spec-11.txt
185 * DCCP-Sync packets are the best choice for upward
186 * probing, since DCCP-Sync probes do not risk application
189 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
190 } /* else let the usual retransmit timer handle it */
193 static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
196 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
197 const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
198 sizeof(struct dccp_hdr_ext) +
199 sizeof(struct dccp_hdr_ack_bits);
202 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
205 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
209 /* Reserve space for headers. */
210 skb_reserve(skb, MAX_DCCP_HEADER);
212 skb->dst = dst_clone(rxskb->dst);
214 skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
216 memset(dh, 0, dccp_hdr_ack_len);
218 /* Build DCCP header and checksum it. */
219 dh->dccph_type = DCCP_PKT_ACK;
220 dh->dccph_sport = rxdh->dccph_dport;
221 dh->dccph_dport = rxdh->dccph_sport;
222 dh->dccph_doff = dccp_hdr_ack_len / 4;
225 dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
226 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
227 DCCP_SKB_CB(rxskb)->dccpd_seq);
229 bh_lock_sock(dccp_ctl_socket->sk);
230 err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
231 rxskb->nh.iph->daddr,
232 rxskb->nh.iph->saddr, NULL);
233 bh_unlock_sock(dccp_ctl_socket->sk);
235 if (err == NET_XMIT_CN || err == 0) {
236 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
237 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
241 static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
242 struct request_sock *req)
244 dccp_v4_ctl_send_ack(skb);
247 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
248 struct dst_entry *dst)
253 /* First, grab a route. */
255 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
258 skb = dccp_make_response(sk, dst, req);
260 const struct inet_request_sock *ireq = inet_rsk(req);
261 struct dccp_hdr *dh = dccp_hdr(skb);
263 dh->dccph_checksum = dccp_v4_checksum(skb, ireq->loc_addr,
265 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
266 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
269 if (err == NET_XMIT_CN)
279 * This routine is called by the ICMP module when it gets some sort of error
280 * condition. If err < 0 then the socket should be closed and the error
281 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
282 * After adjustment header points to the first 8 bytes of the tcp header. We
283 * need to find the appropriate port.
285 * The locking strategy used here is very "optimistic". When someone else
286 * accesses the socket the ICMP is just dropped and for some paths there is no
287 * check at all. A more general error queue to queue errors for later handling
288 * is probably better.
290 static void dccp_v4_err(struct sk_buff *skb, u32 info)
292 const struct iphdr *iph = (struct iphdr *)skb->data;
293 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
295 struct dccp_sock *dp;
296 struct inet_sock *inet;
297 const int type = skb->h.icmph->type;
298 const int code = skb->h.icmph->code;
303 if (skb->len < (iph->ihl << 2) + 8) {
304 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
308 sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
309 iph->saddr, dh->dccph_sport, inet_iif(skb));
311 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
315 if (sk->sk_state == DCCP_TIME_WAIT) {
316 inet_twsk_put((struct inet_timewait_sock *)sk);
321 /* If too many ICMPs get dropped on busy
322 * servers this needs to be solved differently.
324 if (sock_owned_by_user(sk))
325 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
327 if (sk->sk_state == DCCP_CLOSED)
331 seq = dccp_hdr_seq(skb);
332 if (sk->sk_state != DCCP_LISTEN &&
333 !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
334 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
339 case ICMP_SOURCE_QUENCH:
340 /* Just silently ignore these. */
342 case ICMP_PARAMETERPROB:
345 case ICMP_DEST_UNREACH:
346 if (code > NR_ICMP_UNREACH)
349 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
350 if (!sock_owned_by_user(sk))
351 dccp_do_pmtu_discovery(sk, iph, info);
355 err = icmp_err_convert[code].errno;
357 case ICMP_TIME_EXCEEDED:
364 switch (sk->sk_state) {
365 struct request_sock *req , **prev;
367 if (sock_owned_by_user(sk))
369 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
370 iph->daddr, iph->saddr);
375 * ICMPs are not backlogged, hence we cannot get an established
380 if (seq != dccp_rsk(req)->dreq_iss) {
381 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
385 * Still in RESPOND, just remove it silently.
386 * There is no good way to pass the error to the newly
387 * created socket, and POSIX does not want network
388 * errors returned from accept().
390 inet_csk_reqsk_queue_drop(sk, req, prev);
393 case DCCP_REQUESTING:
395 if (!sock_owned_by_user(sk)) {
396 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
399 sk->sk_error_report(sk);
403 sk->sk_err_soft = err;
407 /* If we've already connected we will keep trying
408 * until we time out, or the user gives up.
410 * rfc1122 4.2.3.9 allows to consider as hard errors
411 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
412 * but it is obsoleted by pmtu discovery).
414 * Note, that in modern internet, where routing is unreliable
415 * and in each dark corner broken firewalls sit, sending random
416 * errors ordered by their masters even this two messages finally lose
417 * their original sense (even Linux sends invalid PORT_UNREACHs)
419 * Now we are in compliance with RFCs.
424 if (!sock_owned_by_user(sk) && inet->recverr) {
426 sk->sk_error_report(sk);
427 } else /* Only an error on timeout */
428 sk->sk_err_soft = err;
434 /* This routine computes an IPv4 DCCP checksum. */
435 void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
437 const struct inet_sock *inet = inet_sk(sk);
438 struct dccp_hdr *dh = dccp_hdr(skb);
440 dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr, inet->daddr);
443 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
445 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
446 const struct sk_buff *skb)
448 return secure_dccp_sequence_number(skb->nh.iph->daddr,
450 dccp_hdr(skb)->dccph_dport,
451 dccp_hdr(skb)->dccph_sport);
454 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
456 struct inet_request_sock *ireq;
458 struct request_sock *req;
459 struct dccp_request_sock *dreq;
460 const __be32 saddr = skb->nh.iph->saddr;
461 const __be32 daddr = skb->nh.iph->daddr;
462 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
463 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
464 __u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
466 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
467 if (((struct rtable *)skb->dst)->rt_flags &
468 (RTCF_BROADCAST | RTCF_MULTICAST)) {
469 reset_code = DCCP_RESET_CODE_NO_CONNECTION;
473 if (dccp_bad_service_code(sk, service)) {
474 reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
478 * TW buckets are converted to open requests without
479 * limitations, they conserve resources and peer is
480 * evidently real one.
482 if (inet_csk_reqsk_queue_is_full(sk))
486 * Accept backlog is full. If we have already queued enough
487 * of warm entries in syn queue, drop request. It is better than
488 * clogging syn queue with openreqs with exponentially increasing
491 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
494 req = reqsk_alloc(sk->sk_prot->rsk_prot);
498 if (dccp_parse_options(sk, skb))
501 dccp_openreq_init(req, &dp, skb);
503 ireq = inet_rsk(req);
504 ireq->loc_addr = daddr;
505 ireq->rmt_addr = saddr;
506 req->rcv_wnd = 100; /* Fake, option parsing will get the
511 * Step 3: Process LISTEN state
513 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
515 * In fact we defer setting S.GSR, S.SWL, S.SWH to
516 * dccp_create_openreq_child.
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;
523 if (dccp_v4_send_response(sk, req, NULL))
526 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
532 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
533 dcb->dccpd_reset_code = reset_code;
537 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
540 * The three way handshake has completed - we got a valid ACK or DATAACK -
541 * now create the new socket.
543 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
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)
549 struct inet_request_sock *ireq;
550 struct inet_sock *newinet;
551 struct dccp_sock *newdp;
554 if (sk_acceptq_is_full(sk))
557 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
560 newsk = dccp_create_openreq_child(sk, req, skb);
564 sk_setup_caps(newsk, dst);
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;
574 newinet->mc_index = inet_iif(skb);
575 newinet->mc_ttl = skb->nh.iph->ttl;
576 newinet->id = jiffies;
578 dccp_sync_mss(newsk, dst_mtu(dst));
580 __inet_hash(&dccp_hashinfo, newsk, 0);
581 __inet_inherit_port(&dccp_hashinfo, sk, newsk);
586 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
588 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
593 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
595 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
597 const struct dccp_hdr *dh = dccp_hdr(skb);
598 const struct iphdr *iph = skb->nh.iph;
600 struct request_sock **prev;
601 /* Find possible connection requests. */
602 struct request_sock *req = inet_csk_search_req(sk, &prev,
604 iph->saddr, iph->daddr);
606 return dccp_check_req(sk, skb, req, prev);
608 nsk = __inet_lookup_established(&dccp_hashinfo,
609 iph->saddr, dh->dccph_sport,
610 iph->daddr, ntohs(dh->dccph_dport),
613 if (nsk->sk_state != DCCP_TIME_WAIT) {
617 inet_twsk_put((struct inet_timewait_sock *)nsk);
624 int dccp_v4_checksum(const struct sk_buff *skb, const __be32 saddr,
627 const struct dccp_hdr* dh = dccp_hdr(skb);
631 if (dh->dccph_cscov == 0)
632 checksum_len = skb->len;
634 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
635 checksum_len = checksum_len < skb->len ? checksum_len :
639 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
640 return csum_tcpudp_magic(saddr, daddr, checksum_len,
644 EXPORT_SYMBOL_GPL(dccp_v4_checksum);
646 static int dccp_v4_verify_checksum(struct sk_buff *skb,
647 const __be32 saddr, const __be32 daddr)
649 struct dccp_hdr *dh = dccp_hdr(skb);
653 if (dh->dccph_cscov == 0)
654 checksum_len = skb->len;
656 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
657 checksum_len = checksum_len < skb->len ? checksum_len :
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;
665 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
669 struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
671 { .daddr = skb->nh.iph->saddr,
672 .saddr = skb->nh.iph->daddr,
673 .tos = RT_CONN_FLAGS(sk) } },
674 .proto = sk->sk_protocol,
676 { .sport = dccp_hdr(skb)->dccph_dport,
677 .dport = dccp_hdr(skb)->dccph_sport }
681 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
682 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
689 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
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);
697 struct dst_entry *dst;
700 /* Never send a reset in response to a reset. */
701 if (rxdh->dccph_type == DCCP_PKT_RESET)
704 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
707 dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
711 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
715 /* Reserve space for headers. */
716 skb_reserve(skb, MAX_DCCP_HEADER);
717 skb->dst = dst_clone(dst);
719 skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
721 memset(dh, 0, dccp_hdr_reset_len);
723 /* Build DCCP header and checksum it. */
724 dh->dccph_type = DCCP_PKT_RESET;
725 dh->dccph_sport = rxdh->dccph_dport;
726 dh->dccph_dport = rxdh->dccph_sport;
727 dh->dccph_doff = dccp_hdr_reset_len / 4;
729 dccp_hdr_reset(skb)->dccph_reset_code =
730 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
732 /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
734 if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
735 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
737 dccp_hdr_set_seq(dh, seqno);
738 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
739 DCCP_SKB_CB(rxskb)->dccpd_seq);
741 dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
742 rxskb->nh.iph->daddr);
744 bh_lock_sock(dccp_ctl_socket->sk);
745 err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
746 rxskb->nh.iph->daddr,
747 rxskb->nh.iph->saddr, NULL);
748 bh_unlock_sock(dccp_ctl_socket->sk);
750 if (err == NET_XMIT_CN || err == 0) {
751 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
752 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
758 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
760 struct dccp_hdr *dh = dccp_hdr(skb);
762 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
763 if (dccp_rcv_established(sk, skb, dh, skb->len))
769 * Step 3: Process LISTEN state
770 * If S.state == LISTEN,
771 * If P.type == Request or P contains a valid Init Cookie
773 * * Must scan the packet's options to check for an Init
774 * Cookie. Only the Init Cookie is processed here,
775 * however; other options are processed in Step 8. This
776 * scan need only be performed if the endpoint uses Init
778 * * Generate a new socket and switch to that socket *
779 * Set S := new socket for this port pair
781 * Choose S.ISS (initial seqno) or set from Init Cookie
782 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
783 * Continue with S.state == RESPOND
784 * * A Response packet will be generated in Step 11 *
786 * Generate Reset(No Connection) unless P.type == Reset
787 * Drop packet and return
789 * NOTE: the check for the packet types is done in
790 * dccp_rcv_state_process
792 if (sk->sk_state == DCCP_LISTEN) {
793 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
799 if (dccp_child_process(sk, nsk, skb))
805 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
810 dccp_v4_ctl_send_reset(skb);
816 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
818 int dccp_invalid_packet(struct sk_buff *skb)
820 const struct dccp_hdr *dh;
822 if (skb->pkt_type != PACKET_HOST)
825 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
826 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
832 /* If the packet type is not understood, drop packet and return */
833 if (dh->dccph_type >= DCCP_PKT_INVALID) {
834 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
839 * If P.Data Offset is too small for packet type, or too large for
840 * packet, drop packet and return
842 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
843 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
849 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
850 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
859 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
860 * has short sequence numbers), drop packet and return
862 if (dh->dccph_x == 0 &&
863 dh->dccph_type != DCCP_PKT_DATA &&
864 dh->dccph_type != DCCP_PKT_ACK &&
865 dh->dccph_type != DCCP_PKT_DATAACK) {
866 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
867 "nor DataAck and P.X == 0\n",
868 dccp_packet_name(dh->dccph_type));
875 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
877 /* this is called when real data arrives */
878 static int dccp_v4_rcv(struct sk_buff *skb)
880 const struct dccp_hdr *dh;
883 /* Step 1: Check header basics: */
885 if (dccp_invalid_packet(skb))
888 /* If the header checksum is incorrect, drop packet and return */
889 if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
890 skb->nh.iph->daddr) < 0) {
891 LIMIT_NETDEBUG(KERN_WARNING "%s: incorrect header checksum\n",
898 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
899 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
901 dccp_pr_debug("%8.8s "
902 "src=%u.%u.%u.%u@%-5d "
903 "dst=%u.%u.%u.%u@%-5d seq=%llu",
904 dccp_packet_name(dh->dccph_type),
905 NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
906 NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
907 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
909 if (dccp_packet_without_ack(skb)) {
910 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
911 dccp_pr_debug_cat("\n");
913 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
914 dccp_pr_debug_cat(", ack=%llu\n",
916 DCCP_SKB_CB(skb)->dccpd_ack_seq);
920 * Look up flow ID in table and get corresponding socket */
921 sk = __inet_lookup(&dccp_hashinfo,
922 skb->nh.iph->saddr, dh->dccph_sport,
923 skb->nh.iph->daddr, ntohs(dh->dccph_dport),
929 * Generate Reset(No Connection) unless P.type == Reset
930 * Drop packet and return
933 dccp_pr_debug("failed to look up flow ID in table and "
934 "get corresponding socket\n");
940 * ... or S.state == TIMEWAIT,
941 * Generate Reset(No Connection) unless P.type == Reset
942 * Drop packet and return
945 if (sk->sk_state == DCCP_TIME_WAIT) {
946 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
951 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
952 goto discard_and_relse;
955 return sk_receive_skb(sk, skb);
958 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
962 * Generate Reset(No Connection) unless P.type == Reset
963 * Drop packet and return
965 if (dh->dccph_type != DCCP_PKT_RESET) {
966 DCCP_SKB_CB(skb)->dccpd_reset_code =
967 DCCP_RESET_CODE_NO_CONNECTION;
968 dccp_v4_ctl_send_reset(skb);
981 inet_twsk_put((struct inet_timewait_sock *)sk);
985 static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
986 .queue_xmit = ip_queue_xmit,
987 .send_check = dccp_v4_send_check,
988 .rebuild_header = inet_sk_rebuild_header,
989 .conn_request = dccp_v4_conn_request,
990 .syn_recv_sock = dccp_v4_request_recv_sock,
991 .net_header_len = sizeof(struct iphdr),
992 .setsockopt = ip_setsockopt,
993 .getsockopt = ip_getsockopt,
994 .addr2sockaddr = inet_csk_addr2sockaddr,
995 .sockaddr_len = sizeof(struct sockaddr_in),
998 static int dccp_v4_init_sock(struct sock *sk)
1000 const int err = dccp_init_sock(sk);
1003 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
1007 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1009 kfree(inet_rsk(req)->opt);
1012 static struct request_sock_ops dccp_request_sock_ops = {
1014 .obj_size = sizeof(struct dccp_request_sock),
1015 .rtx_syn_ack = dccp_v4_send_response,
1016 .send_ack = dccp_v4_reqsk_send_ack,
1017 .destructor = dccp_v4_reqsk_destructor,
1018 .send_reset = dccp_v4_ctl_send_reset,
1021 static struct timewait_sock_ops dccp_timewait_sock_ops = {
1022 .twsk_obj_size = sizeof(struct inet_timewait_sock),
1025 static struct proto dccp_v4_prot = {
1027 .owner = THIS_MODULE,
1028 .close = dccp_close,
1029 .connect = dccp_v4_connect,
1030 .disconnect = dccp_disconnect,
1031 .ioctl = dccp_ioctl,
1032 .init = dccp_v4_init_sock,
1033 .setsockopt = dccp_setsockopt,
1034 .getsockopt = dccp_getsockopt,
1035 .sendmsg = dccp_sendmsg,
1036 .recvmsg = dccp_recvmsg,
1037 .backlog_rcv = dccp_v4_do_rcv,
1039 .unhash = dccp_unhash,
1040 .accept = inet_csk_accept,
1041 .get_port = dccp_v4_get_port,
1042 .shutdown = dccp_shutdown,
1043 .destroy = dccp_destroy_sock,
1044 .orphan_count = &dccp_orphan_count,
1045 .max_header = MAX_DCCP_HEADER,
1046 .obj_size = sizeof(struct dccp_sock),
1047 .rsk_prot = &dccp_request_sock_ops,
1048 .twsk_prot = &dccp_timewait_sock_ops,
1051 static struct net_protocol dccp_v4_protocol = {
1052 .handler = dccp_v4_rcv,
1053 .err_handler = dccp_v4_err,
1057 static const struct proto_ops inet_dccp_ops = {
1059 .owner = THIS_MODULE,
1060 .release = inet_release,
1062 .connect = inet_stream_connect,
1063 .socketpair = sock_no_socketpair,
1064 .accept = inet_accept,
1065 .getname = inet_getname,
1066 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1068 .ioctl = inet_ioctl,
1069 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1070 .listen = inet_dccp_listen,
1071 .shutdown = inet_shutdown,
1072 .setsockopt = sock_common_setsockopt,
1073 .getsockopt = sock_common_getsockopt,
1074 .sendmsg = inet_sendmsg,
1075 .recvmsg = sock_common_recvmsg,
1076 .mmap = sock_no_mmap,
1077 .sendpage = sock_no_sendpage,
1080 static struct inet_protosw dccp_v4_protosw = {
1082 .protocol = IPPROTO_DCCP,
1083 .prot = &dccp_v4_prot,
1084 .ops = &inet_dccp_ops,
1087 .flags = INET_PROTOSW_ICSK,
1091 * This is the global socket data structure used for responding to
1092 * the Out-of-the-blue (OOTB) packets. A control sock will be created
1093 * for this socket at the initialization time.
1095 struct socket *dccp_ctl_socket;
1097 static char dccp_ctl_socket_err_msg[] __initdata =
1098 KERN_ERR "DCCP: Failed to create the control socket.\n";
1100 static int __init dccp_ctl_sock_init(void)
1102 int rc = sock_create_kern(PF_INET, SOCK_DCCP, IPPROTO_DCCP,
1105 printk(dccp_ctl_socket_err_msg);
1107 dccp_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
1108 inet_sk(dccp_ctl_socket->sk)->uc_ttl = -1;
1110 /* Unhash it so that IP input processing does not even
1111 * see it, we do not wish this socket to see incoming
1114 dccp_ctl_socket->sk->sk_prot->unhash(dccp_ctl_socket->sk);
1120 #ifdef CONFIG_IP_DCCP_UNLOAD_HACK
1121 void dccp_ctl_sock_exit(void)
1123 if (dccp_ctl_socket != NULL) {
1124 sock_release(dccp_ctl_socket);
1125 dccp_ctl_socket = NULL;
1129 EXPORT_SYMBOL_GPL(dccp_ctl_sock_exit);
1132 static int __init dccp_v4_init(void)
1134 int err = proto_register(&dccp_v4_prot, 1);
1139 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1141 goto out_proto_unregister;
1143 inet_register_protosw(&dccp_v4_protosw);
1145 err = dccp_ctl_sock_init();
1147 goto out_unregister_protosw;
1150 out_unregister_protosw:
1151 inet_unregister_protosw(&dccp_v4_protosw);
1152 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1153 out_proto_unregister:
1154 proto_unregister(&dccp_v4_prot);
1158 static void __exit dccp_v4_exit(void)
1160 inet_unregister_protosw(&dccp_v4_protosw);
1161 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1162 proto_unregister(&dccp_v4_prot);
1165 module_init(dccp_v4_init);
1166 module_exit(dccp_v4_exit);
1169 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1170 * values directly, Also cover the case where the protocol is not specified,
1171 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1173 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-33-type-6");
1174 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-0-type-6");
1175 MODULE_LICENSE("GPL");
1176 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1177 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");