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_hashtables.h>
22 #include <net/inet_sock.h>
24 #include <net/timewait_sock.h>
25 #include <net/tcp_states.h>
33 struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
34 .lhash_lock = RW_LOCK_UNLOCKED,
35 .lhash_users = ATOMIC_INIT(0),
36 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
39 EXPORT_SYMBOL_GPL(dccp_hashinfo);
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 static void dccp_v4_hash(struct sock *sk)
49 inet_hash(&dccp_hashinfo, sk);
52 void dccp_unhash(struct sock *sk)
54 inet_unhash(&dccp_hashinfo, sk);
57 EXPORT_SYMBOL_GPL(dccp_unhash);
59 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
61 struct inet_sock *inet = inet_sk(sk);
62 struct dccp_sock *dp = dccp_sk(sk);
63 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
69 dp->dccps_role = DCCP_ROLE_CLIENT;
71 if (dccp_service_not_initialized(sk))
74 if (addr_len < sizeof(struct sockaddr_in))
77 if (usin->sin_family != AF_INET)
80 nexthop = daddr = usin->sin_addr.s_addr;
81 if (inet->opt != NULL && inet->opt->srr) {
84 nexthop = inet->opt->faddr;
87 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
88 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
90 inet->sport, usin->sin_port, sk);
94 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
99 if (inet->opt == NULL || !inet->opt->srr)
102 if (inet->saddr == 0)
103 inet->saddr = rt->rt_src;
104 inet->rcv_saddr = inet->saddr;
106 inet->dport = usin->sin_port;
109 inet_csk(sk)->icsk_ext_hdr_len = 0;
110 if (inet->opt != NULL)
111 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
113 * Socket identity is still unknown (sport may be zero).
114 * However we set state to DCCP_REQUESTING and not releasing socket
115 * lock select source port, enter ourselves into the hash tables and
116 * complete initialization after this.
118 dccp_set_state(sk, DCCP_REQUESTING);
119 err = inet_hash_connect(&dccp_death_row, sk);
123 err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
128 /* OK, now commit destination to socket. */
129 sk_setup_caps(sk, &rt->u.dst);
132 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
136 dccp_update_gss(sk, dp->dccps_iss);
138 inet->id = dp->dccps_iss ^ jiffies;
140 err = dccp_connect(sk);
148 * This unhashes the socket and releases the local port, if necessary.
150 dccp_set_state(sk, DCCP_CLOSED);
152 sk->sk_route_caps = 0;
157 EXPORT_SYMBOL_GPL(dccp_v4_connect);
160 * This routine does path mtu discovery as defined in RFC1191.
162 static inline void dccp_do_pmtu_discovery(struct sock *sk,
163 const struct iphdr *iph,
166 struct dst_entry *dst;
167 const struct inet_sock *inet = inet_sk(sk);
168 const struct dccp_sock *dp = dccp_sk(sk);
170 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
171 * send out by Linux are always < 576bytes so they should go through
174 if (sk->sk_state == DCCP_LISTEN)
177 /* We don't check in the destentry if pmtu discovery is forbidden
178 * on this route. We just assume that no packet_to_big packets
179 * are send back when pmtu discovery is not active.
180 * There is a small race when the user changes this flag in the
181 * route, but I think that's acceptable.
183 if ((dst = __sk_dst_check(sk, 0)) == NULL)
186 dst->ops->update_pmtu(dst, mtu);
188 /* Something is about to be wrong... Remember soft error
189 * for the case, if this connection will not able to recover.
191 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
192 sk->sk_err_soft = EMSGSIZE;
196 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
197 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
198 dccp_sync_mss(sk, mtu);
201 * From: draft-ietf-dccp-spec-11.txt
203 * DCCP-Sync packets are the best choice for upward
204 * probing, since DCCP-Sync probes do not risk application
207 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
208 } /* else let the usual retransmit timer handle it */
211 static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
214 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
215 const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
216 sizeof(struct dccp_hdr_ext) +
217 sizeof(struct dccp_hdr_ack_bits);
220 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
223 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
227 /* Reserve space for headers. */
228 skb_reserve(skb, MAX_DCCP_HEADER);
230 skb->dst = dst_clone(rxskb->dst);
232 skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
234 memset(dh, 0, dccp_hdr_ack_len);
236 /* Build DCCP header and checksum it. */
237 dh->dccph_type = DCCP_PKT_ACK;
238 dh->dccph_sport = rxdh->dccph_dport;
239 dh->dccph_dport = rxdh->dccph_sport;
240 dh->dccph_doff = dccp_hdr_ack_len / 4;
243 dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
244 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
245 DCCP_SKB_CB(rxskb)->dccpd_seq);
247 bh_lock_sock(dccp_ctl_socket->sk);
248 err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
249 rxskb->nh.iph->daddr,
250 rxskb->nh.iph->saddr, NULL);
251 bh_unlock_sock(dccp_ctl_socket->sk);
253 if (err == NET_XMIT_CN || err == 0) {
254 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
255 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
259 static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
260 struct request_sock *req)
262 dccp_v4_ctl_send_ack(skb);
265 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
266 struct dst_entry *dst)
271 /* First, grab a route. */
273 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
276 skb = dccp_make_response(sk, dst, req);
278 const struct inet_request_sock *ireq = inet_rsk(req);
280 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
281 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
284 if (err == NET_XMIT_CN)
294 * This routine is called by the ICMP module when it gets some sort of error
295 * condition. If err < 0 then the socket should be closed and the error
296 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
297 * After adjustment header points to the first 8 bytes of the tcp header. We
298 * need to find the appropriate port.
300 * The locking strategy used here is very "optimistic". When someone else
301 * accesses the socket the ICMP is just dropped and for some paths there is no
302 * check at all. A more general error queue to queue errors for later handling
303 * is probably better.
305 void dccp_v4_err(struct sk_buff *skb, u32 info)
307 const struct iphdr *iph = (struct iphdr *)skb->data;
308 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
310 struct dccp_sock *dp;
311 struct inet_sock *inet;
312 const int type = skb->h.icmph->type;
313 const int code = skb->h.icmph->code;
318 if (skb->len < (iph->ihl << 2) + 8) {
319 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
323 sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
324 iph->saddr, dh->dccph_sport, inet_iif(skb));
326 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
330 if (sk->sk_state == DCCP_TIME_WAIT) {
331 inet_twsk_put((struct inet_timewait_sock *)sk);
336 /* If too many ICMPs get dropped on busy
337 * servers this needs to be solved differently.
339 if (sock_owned_by_user(sk))
340 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
342 if (sk->sk_state == DCCP_CLOSED)
346 seq = dccp_hdr_seq(skb);
347 if (sk->sk_state != DCCP_LISTEN &&
348 !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
349 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
354 case ICMP_SOURCE_QUENCH:
355 /* Just silently ignore these. */
357 case ICMP_PARAMETERPROB:
360 case ICMP_DEST_UNREACH:
361 if (code > NR_ICMP_UNREACH)
364 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
365 if (!sock_owned_by_user(sk))
366 dccp_do_pmtu_discovery(sk, iph, info);
370 err = icmp_err_convert[code].errno;
372 case ICMP_TIME_EXCEEDED:
379 switch (sk->sk_state) {
380 struct request_sock *req , **prev;
382 if (sock_owned_by_user(sk))
384 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
385 iph->daddr, iph->saddr);
390 * ICMPs are not backlogged, hence we cannot get an established
395 if (seq != dccp_rsk(req)->dreq_iss) {
396 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
400 * Still in RESPOND, just remove it silently.
401 * There is no good way to pass the error to the newly
402 * created socket, and POSIX does not want network
403 * errors returned from accept().
405 inet_csk_reqsk_queue_drop(sk, req, prev);
408 case DCCP_REQUESTING:
410 if (!sock_owned_by_user(sk)) {
411 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
414 sk->sk_error_report(sk);
418 sk->sk_err_soft = err;
422 /* If we've already connected we will keep trying
423 * until we time out, or the user gives up.
425 * rfc1122 4.2.3.9 allows to consider as hard errors
426 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
427 * but it is obsoleted by pmtu discovery).
429 * Note, that in modern internet, where routing is unreliable
430 * and in each dark corner broken firewalls sit, sending random
431 * errors ordered by their masters even this two messages finally lose
432 * their original sense (even Linux sends invalid PORT_UNREACHs)
434 * Now we are in compliance with RFCs.
439 if (!sock_owned_by_user(sk) && inet->recverr) {
441 sk->sk_error_report(sk);
442 } else /* Only an error on timeout */
443 sk->sk_err_soft = err;
449 /* This routine computes an IPv4 DCCP checksum. */
450 void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
452 const struct inet_sock *inet = inet_sk(sk);
453 struct dccp_hdr *dh = dccp_hdr(skb);
455 dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr, inet->daddr);
458 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
460 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
461 const struct sk_buff *skb)
463 return secure_dccp_sequence_number(skb->nh.iph->daddr,
465 dccp_hdr(skb)->dccph_dport,
466 dccp_hdr(skb)->dccph_sport);
469 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
471 struct inet_request_sock *ireq;
473 struct request_sock *req;
474 struct dccp_request_sock *dreq;
475 const __be32 saddr = skb->nh.iph->saddr;
476 const __be32 daddr = skb->nh.iph->daddr;
477 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
478 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
479 __u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
481 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
482 if (((struct rtable *)skb->dst)->rt_flags &
483 (RTCF_BROADCAST | RTCF_MULTICAST)) {
484 reset_code = DCCP_RESET_CODE_NO_CONNECTION;
488 if (dccp_bad_service_code(sk, service)) {
489 reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
493 * TW buckets are converted to open requests without
494 * limitations, they conserve resources and peer is
495 * evidently real one.
497 if (inet_csk_reqsk_queue_is_full(sk))
501 * Accept backlog is full. If we have already queued enough
502 * of warm entries in syn queue, drop request. It is better than
503 * clogging syn queue with openreqs with exponentially increasing
506 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
509 req = reqsk_alloc(sk->sk_prot->rsk_prot);
513 if (dccp_parse_options(sk, skb))
516 dccp_openreq_init(req, &dp, skb);
518 ireq = inet_rsk(req);
519 ireq->loc_addr = daddr;
520 ireq->rmt_addr = saddr;
521 req->rcv_wnd = 100; /* Fake, option parsing will get the
526 * Step 3: Process LISTEN state
528 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
530 * In fact we defer setting S.GSR, S.SWL, S.SWH to
531 * dccp_create_openreq_child.
533 dreq = dccp_rsk(req);
534 dreq->dreq_isr = dcb->dccpd_seq;
535 dreq->dreq_iss = dccp_v4_init_sequence(sk, skb);
536 dreq->dreq_service = service;
538 if (dccp_v4_send_response(sk, req, NULL))
541 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
547 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
548 dcb->dccpd_reset_code = reset_code;
552 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
555 * The three way handshake has completed - we got a valid ACK or DATAACK -
556 * now create the new socket.
558 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
560 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
561 struct request_sock *req,
562 struct dst_entry *dst)
564 struct inet_request_sock *ireq;
565 struct inet_sock *newinet;
566 struct dccp_sock *newdp;
569 if (sk_acceptq_is_full(sk))
572 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
575 newsk = dccp_create_openreq_child(sk, req, skb);
579 sk_setup_caps(newsk, dst);
581 newdp = dccp_sk(newsk);
582 newinet = inet_sk(newsk);
583 ireq = inet_rsk(req);
584 newinet->daddr = ireq->rmt_addr;
585 newinet->rcv_saddr = ireq->loc_addr;
586 newinet->saddr = ireq->loc_addr;
587 newinet->opt = ireq->opt;
589 newinet->mc_index = inet_iif(skb);
590 newinet->mc_ttl = skb->nh.iph->ttl;
591 newinet->id = jiffies;
593 dccp_sync_mss(newsk, dst_mtu(dst));
595 __inet_hash(&dccp_hashinfo, newsk, 0);
596 __inet_inherit_port(&dccp_hashinfo, sk, newsk);
601 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
603 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
608 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
610 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
612 const struct dccp_hdr *dh = dccp_hdr(skb);
613 const struct iphdr *iph = skb->nh.iph;
615 struct request_sock **prev;
616 /* Find possible connection requests. */
617 struct request_sock *req = inet_csk_search_req(sk, &prev,
619 iph->saddr, iph->daddr);
621 return dccp_check_req(sk, skb, req, prev);
623 nsk = __inet_lookup_established(&dccp_hashinfo,
624 iph->saddr, dh->dccph_sport,
625 iph->daddr, ntohs(dh->dccph_dport),
628 if (nsk->sk_state != DCCP_TIME_WAIT) {
632 inet_twsk_put((struct inet_timewait_sock *)nsk);
639 int dccp_v4_checksum(const struct sk_buff *skb, const __be32 saddr,
642 const struct dccp_hdr* dh = dccp_hdr(skb);
646 if (dh->dccph_cscov == 0)
647 checksum_len = skb->len;
649 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
650 checksum_len = checksum_len < skb->len ? checksum_len :
654 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
655 return csum_tcpudp_magic(saddr, daddr, checksum_len,
659 static int dccp_v4_verify_checksum(struct sk_buff *skb,
660 const __be32 saddr, const __be32 daddr)
662 struct dccp_hdr *dh = dccp_hdr(skb);
666 if (dh->dccph_cscov == 0)
667 checksum_len = skb->len;
669 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
670 checksum_len = checksum_len < skb->len ? checksum_len :
673 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
674 return csum_tcpudp_magic(saddr, daddr, checksum_len,
675 IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
678 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
682 struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
684 { .daddr = skb->nh.iph->saddr,
685 .saddr = skb->nh.iph->daddr,
686 .tos = RT_CONN_FLAGS(sk) } },
687 .proto = sk->sk_protocol,
689 { .sport = dccp_hdr(skb)->dccph_dport,
690 .dport = dccp_hdr(skb)->dccph_sport }
694 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
695 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
702 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
705 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
706 const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
707 sizeof(struct dccp_hdr_ext) +
708 sizeof(struct dccp_hdr_reset);
710 struct dst_entry *dst;
713 /* Never send a reset in response to a reset. */
714 if (rxdh->dccph_type == DCCP_PKT_RESET)
717 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
720 dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
724 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
728 /* Reserve space for headers. */
729 skb_reserve(skb, MAX_DCCP_HEADER);
730 skb->dst = dst_clone(dst);
732 skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
734 memset(dh, 0, dccp_hdr_reset_len);
736 /* Build DCCP header and checksum it. */
737 dh->dccph_type = DCCP_PKT_RESET;
738 dh->dccph_sport = rxdh->dccph_dport;
739 dh->dccph_dport = rxdh->dccph_sport;
740 dh->dccph_doff = dccp_hdr_reset_len / 4;
742 dccp_hdr_reset(skb)->dccph_reset_code =
743 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
745 /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
747 if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
748 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
750 dccp_hdr_set_seq(dh, seqno);
751 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
752 DCCP_SKB_CB(rxskb)->dccpd_seq);
754 dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
755 rxskb->nh.iph->daddr);
757 bh_lock_sock(dccp_ctl_socket->sk);
758 err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
759 rxskb->nh.iph->daddr,
760 rxskb->nh.iph->saddr, NULL);
761 bh_unlock_sock(dccp_ctl_socket->sk);
763 if (err == NET_XMIT_CN || err == 0) {
764 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
765 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
771 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
773 struct dccp_hdr *dh = dccp_hdr(skb);
775 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
776 if (dccp_rcv_established(sk, skb, dh, skb->len))
782 * Step 3: Process LISTEN state
783 * If S.state == LISTEN,
784 * If P.type == Request or P contains a valid Init Cookie
786 * * Must scan the packet's options to check for an Init
787 * Cookie. Only the Init Cookie is processed here,
788 * however; other options are processed in Step 8. This
789 * scan need only be performed if the endpoint uses Init
791 * * Generate a new socket and switch to that socket *
792 * Set S := new socket for this port pair
794 * Choose S.ISS (initial seqno) or set from Init Cookie
795 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
796 * Continue with S.state == RESPOND
797 * * A Response packet will be generated in Step 11 *
799 * Generate Reset(No Connection) unless P.type == Reset
800 * Drop packet and return
802 * NOTE: the check for the packet types is done in
803 * dccp_rcv_state_process
805 if (sk->sk_state == DCCP_LISTEN) {
806 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
812 if (dccp_child_process(sk, nsk, skb))
818 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
823 dccp_v4_ctl_send_reset(skb);
829 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
831 int dccp_invalid_packet(struct sk_buff *skb)
833 const struct dccp_hdr *dh;
835 if (skb->pkt_type != PACKET_HOST)
838 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
839 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
845 /* If the packet type is not understood, drop packet and return */
846 if (dh->dccph_type >= DCCP_PKT_INVALID) {
847 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
852 * If P.Data Offset is too small for packet type, or too large for
853 * packet, drop packet and return
855 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
856 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
862 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
863 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
872 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
873 * has short sequence numbers), drop packet and return
875 if (dh->dccph_x == 0 &&
876 dh->dccph_type != DCCP_PKT_DATA &&
877 dh->dccph_type != DCCP_PKT_ACK &&
878 dh->dccph_type != DCCP_PKT_DATAACK) {
879 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
880 "nor DataAck and P.X == 0\n",
881 dccp_packet_name(dh->dccph_type));
888 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
890 /* this is called when real data arrives */
891 int dccp_v4_rcv(struct sk_buff *skb)
893 const struct dccp_hdr *dh;
896 /* Step 1: Check header basics: */
898 if (dccp_invalid_packet(skb))
901 /* If the header checksum is incorrect, drop packet and return */
902 if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
903 skb->nh.iph->daddr) < 0) {
904 LIMIT_NETDEBUG(KERN_WARNING "%s: incorrect header checksum\n",
911 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
912 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
914 dccp_pr_debug("%8.8s "
915 "src=%u.%u.%u.%u@%-5d "
916 "dst=%u.%u.%u.%u@%-5d seq=%llu",
917 dccp_packet_name(dh->dccph_type),
918 NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
919 NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
920 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
922 if (dccp_packet_without_ack(skb)) {
923 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
924 dccp_pr_debug_cat("\n");
926 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
927 dccp_pr_debug_cat(", ack=%llu\n",
929 DCCP_SKB_CB(skb)->dccpd_ack_seq);
933 * Look up flow ID in table and get corresponding socket */
934 sk = __inet_lookup(&dccp_hashinfo,
935 skb->nh.iph->saddr, dh->dccph_sport,
936 skb->nh.iph->daddr, ntohs(dh->dccph_dport),
942 * Generate Reset(No Connection) unless P.type == Reset
943 * Drop packet and return
946 dccp_pr_debug("failed to look up flow ID in table and "
947 "get corresponding socket\n");
953 * ... or S.state == TIMEWAIT,
954 * Generate Reset(No Connection) unless P.type == Reset
955 * Drop packet and return
958 if (sk->sk_state == DCCP_TIME_WAIT) {
959 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
964 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
965 goto discard_and_relse;
968 return sk_receive_skb(sk, skb);
971 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
975 * Generate Reset(No Connection) unless P.type == Reset
976 * Drop packet and return
978 if (dh->dccph_type != DCCP_PKT_RESET) {
979 DCCP_SKB_CB(skb)->dccpd_reset_code =
980 DCCP_RESET_CODE_NO_CONNECTION;
981 dccp_v4_ctl_send_reset(skb);
994 inet_twsk_put((struct inet_timewait_sock *)sk);
998 struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
999 .queue_xmit = ip_queue_xmit,
1000 .send_check = dccp_v4_send_check,
1001 .rebuild_header = inet_sk_rebuild_header,
1002 .conn_request = dccp_v4_conn_request,
1003 .syn_recv_sock = dccp_v4_request_recv_sock,
1004 .net_header_len = sizeof(struct iphdr),
1005 .setsockopt = ip_setsockopt,
1006 .getsockopt = ip_getsockopt,
1007 .addr2sockaddr = inet_csk_addr2sockaddr,
1008 .sockaddr_len = sizeof(struct sockaddr_in),
1011 static int dccp_v4_init_sock(struct sock *sk)
1013 const int err = dccp_init_sock(sk);
1016 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
1020 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1022 kfree(inet_rsk(req)->opt);
1025 static struct request_sock_ops dccp_request_sock_ops = {
1027 .obj_size = sizeof(struct dccp_request_sock),
1028 .rtx_syn_ack = dccp_v4_send_response,
1029 .send_ack = dccp_v4_reqsk_send_ack,
1030 .destructor = dccp_v4_reqsk_destructor,
1031 .send_reset = dccp_v4_ctl_send_reset,
1034 static struct timewait_sock_ops dccp_timewait_sock_ops = {
1035 .twsk_obj_size = sizeof(struct inet_timewait_sock),
1038 struct proto dccp_prot = {
1040 .owner = THIS_MODULE,
1041 .close = dccp_close,
1042 .connect = dccp_v4_connect,
1043 .disconnect = dccp_disconnect,
1044 .ioctl = dccp_ioctl,
1045 .init = dccp_v4_init_sock,
1046 .setsockopt = dccp_setsockopt,
1047 .getsockopt = dccp_getsockopt,
1048 .sendmsg = dccp_sendmsg,
1049 .recvmsg = dccp_recvmsg,
1050 .backlog_rcv = dccp_v4_do_rcv,
1051 .hash = dccp_v4_hash,
1052 .unhash = dccp_unhash,
1053 .accept = inet_csk_accept,
1054 .get_port = dccp_v4_get_port,
1055 .shutdown = dccp_shutdown,
1056 .destroy = dccp_destroy_sock,
1057 .orphan_count = &dccp_orphan_count,
1058 .max_header = MAX_DCCP_HEADER,
1059 .obj_size = sizeof(struct dccp_sock),
1060 .rsk_prot = &dccp_request_sock_ops,
1061 .twsk_prot = &dccp_timewait_sock_ops,
1064 EXPORT_SYMBOL_GPL(dccp_prot);