4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
13 #include <linux/dccp.h>
14 #include <linux/icmp.h>
15 #include <linux/slab.h>
16 #include <linux/module.h>
17 #include <linux/skbuff.h>
18 #include <linux/random.h>
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>
29 #include <net/secure_seq.h>
37 * The per-net dccp.v4_ctl_sk socket is used for responding to
38 * the Out-of-the-blue (OOTB) packets. A control sock will be created
39 * for this socket at the initialization time.
42 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
44 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
45 struct inet_sock *inet = inet_sk(sk);
46 struct dccp_sock *dp = dccp_sk(sk);
47 __be16 orig_sport, orig_dport;
48 __be32 daddr, nexthop;
52 struct ip_options_rcu *inet_opt;
54 dp->dccps_role = DCCP_ROLE_CLIENT;
56 if (addr_len < sizeof(struct sockaddr_in))
59 if (usin->sin_family != AF_INET)
62 nexthop = daddr = usin->sin_addr.s_addr;
64 inet_opt = rcu_dereference_protected(inet->inet_opt,
65 sock_owned_by_user(sk));
66 if (inet_opt != NULL && inet_opt->opt.srr) {
69 nexthop = inet_opt->opt.faddr;
72 orig_sport = inet->inet_sport;
73 orig_dport = usin->sin_port;
74 fl4 = &inet->cork.fl.u.ip4;
75 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
76 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
78 orig_sport, orig_dport, sk);
82 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
87 if (inet_opt == NULL || !inet_opt->opt.srr)
90 if (inet->inet_saddr == 0)
91 inet->inet_saddr = fl4->saddr;
92 sk_rcv_saddr_set(sk, inet->inet_saddr);
93 inet->inet_dport = usin->sin_port;
94 sk_daddr_set(sk, daddr);
96 inet_csk(sk)->icsk_ext_hdr_len = 0;
98 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
100 * Socket identity is still unknown (sport may be zero).
101 * However we set state to DCCP_REQUESTING and not releasing socket
102 * lock select source port, enter ourselves into the hash tables and
103 * complete initialization after this.
105 dccp_set_state(sk, DCCP_REQUESTING);
106 err = inet_hash_connect(&dccp_death_row, sk);
110 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
111 inet->inet_sport, inet->inet_dport, sk);
117 /* OK, now commit destination to socket. */
118 sk_setup_caps(sk, &rt->dst);
120 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
124 inet->inet_id = dp->dccps_iss ^ jiffies;
126 err = dccp_connect(sk);
134 * This unhashes the socket and releases the local port, if necessary.
136 dccp_set_state(sk, DCCP_CLOSED);
138 sk->sk_route_caps = 0;
139 inet->inet_dport = 0;
142 EXPORT_SYMBOL_GPL(dccp_v4_connect);
145 * This routine does path mtu discovery as defined in RFC1191.
147 static inline void dccp_do_pmtu_discovery(struct sock *sk,
148 const struct iphdr *iph,
151 struct dst_entry *dst;
152 const struct inet_sock *inet = inet_sk(sk);
153 const struct dccp_sock *dp = dccp_sk(sk);
155 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
156 * send out by Linux are always < 576bytes so they should go through
159 if (sk->sk_state == DCCP_LISTEN)
162 dst = inet_csk_update_pmtu(sk, mtu);
166 /* Something is about to be wrong... Remember soft error
167 * for the case, if this connection will not able to recover.
169 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
170 sk->sk_err_soft = EMSGSIZE;
174 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
175 ip_sk_accept_pmtu(sk) &&
176 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
177 dccp_sync_mss(sk, mtu);
180 * From RFC 4340, sec. 14.1:
182 * DCCP-Sync packets are the best choice for upward
183 * probing, since DCCP-Sync probes do not risk application
186 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
187 } /* else let the usual retransmit timer handle it */
190 static void dccp_do_redirect(struct sk_buff *skb, struct sock *sk)
192 struct dst_entry *dst = __sk_dst_check(sk, 0);
195 dst->ops->redirect(dst, sk, skb);
198 void dccp_req_err(struct sock *sk, u64 seq)
200 struct request_sock *req = inet_reqsk(sk);
201 struct net *net = sock_net(sk);
204 * ICMPs are not backlogged, hence we cannot get an established
209 if (!between48(seq, dccp_rsk(req)->dreq_iss, dccp_rsk(req)->dreq_gss)) {
210 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
214 * Still in RESPOND, just remove it silently.
215 * There is no good way to pass the error to the newly
216 * created socket, and POSIX does not want network
217 * errors returned from accept().
219 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
222 EXPORT_SYMBOL(dccp_req_err);
225 * This routine is called by the ICMP module when it gets some sort of error
226 * condition. If err < 0 then the socket should be closed and the error
227 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
228 * After adjustment header points to the first 8 bytes of the tcp header. We
229 * need to find the appropriate port.
231 * The locking strategy used here is very "optimistic". When someone else
232 * accesses the socket the ICMP is just dropped and for some paths there is no
233 * check at all. A more general error queue to queue errors for later handling
234 * is probably better.
236 static void dccp_v4_err(struct sk_buff *skb, u32 info)
238 const struct iphdr *iph = (struct iphdr *)skb->data;
239 const u8 offset = iph->ihl << 2;
240 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
241 struct dccp_sock *dp;
242 struct inet_sock *inet;
243 const int type = icmp_hdr(skb)->type;
244 const int code = icmp_hdr(skb)->code;
248 struct net *net = dev_net(skb->dev);
250 if (skb->len < offset + sizeof(*dh) ||
251 skb->len < offset + __dccp_basic_hdr_len(dh)) {
252 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
256 sk = __inet_lookup_established(net, &dccp_hashinfo,
257 iph->daddr, dh->dccph_dport,
258 iph->saddr, ntohs(dh->dccph_sport),
261 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
265 if (sk->sk_state == DCCP_TIME_WAIT) {
266 inet_twsk_put(inet_twsk(sk));
269 seq = dccp_hdr_seq(dh);
270 if (sk->sk_state == DCCP_NEW_SYN_RECV)
271 return dccp_req_err(sk, seq);
274 /* If too many ICMPs get dropped on busy
275 * servers this needs to be solved differently.
277 if (sock_owned_by_user(sk))
278 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
280 if (sk->sk_state == DCCP_CLOSED)
284 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
285 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
286 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
292 dccp_do_redirect(skb, sk);
294 case ICMP_SOURCE_QUENCH:
295 /* Just silently ignore these. */
297 case ICMP_PARAMETERPROB:
300 case ICMP_DEST_UNREACH:
301 if (code > NR_ICMP_UNREACH)
304 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
305 if (!sock_owned_by_user(sk))
306 dccp_do_pmtu_discovery(sk, iph, info);
310 err = icmp_err_convert[code].errno;
312 case ICMP_TIME_EXCEEDED:
319 switch (sk->sk_state) {
320 case DCCP_REQUESTING:
322 if (!sock_owned_by_user(sk)) {
323 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
326 sk->sk_error_report(sk);
330 sk->sk_err_soft = err;
334 /* If we've already connected we will keep trying
335 * until we time out, or the user gives up.
337 * rfc1122 4.2.3.9 allows to consider as hard errors
338 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
339 * but it is obsoleted by pmtu discovery).
341 * Note, that in modern internet, where routing is unreliable
342 * and in each dark corner broken firewalls sit, sending random
343 * errors ordered by their masters even this two messages finally lose
344 * their original sense (even Linux sends invalid PORT_UNREACHs)
346 * Now we are in compliance with RFCs.
351 if (!sock_owned_by_user(sk) && inet->recverr) {
353 sk->sk_error_report(sk);
354 } else /* Only an error on timeout */
355 sk->sk_err_soft = err;
361 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
362 __be32 src, __be32 dst)
364 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
367 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
369 const struct inet_sock *inet = inet_sk(sk);
370 struct dccp_hdr *dh = dccp_hdr(skb);
372 dccp_csum_outgoing(skb);
373 dh->dccph_checksum = dccp_v4_csum_finish(skb,
377 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
379 static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
381 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
383 dccp_hdr(skb)->dccph_dport,
384 dccp_hdr(skb)->dccph_sport);
388 * The three way handshake has completed - we got a valid ACK or DATAACK -
389 * now create the new socket.
391 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
393 struct sock *dccp_v4_request_recv_sock(const struct sock *sk,
395 struct request_sock *req,
396 struct dst_entry *dst)
398 struct inet_request_sock *ireq;
399 struct inet_sock *newinet;
402 if (sk_acceptq_is_full(sk))
405 newsk = dccp_create_openreq_child(sk, req, skb);
409 newinet = inet_sk(newsk);
410 ireq = inet_rsk(req);
411 sk_daddr_set(newsk, ireq->ir_rmt_addr);
412 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
413 newinet->inet_saddr = ireq->ir_loc_addr;
414 newinet->inet_opt = ireq->opt;
416 newinet->mc_index = inet_iif(skb);
417 newinet->mc_ttl = ip_hdr(skb)->ttl;
418 newinet->inet_id = jiffies;
420 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
423 sk_setup_caps(newsk, dst);
425 dccp_sync_mss(newsk, dst_mtu(dst));
427 if (__inet_inherit_port(sk, newsk) < 0)
429 __inet_hash_nolisten(newsk, NULL);
434 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
438 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
441 inet_csk_prepare_forced_close(newsk);
445 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
447 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
449 const struct dccp_hdr *dh = dccp_hdr(skb);
450 const struct iphdr *iph = ip_hdr(skb);
452 /* Find possible connection requests. */
453 struct request_sock *req = inet_csk_search_req(sk, dh->dccph_sport,
454 iph->saddr, iph->daddr);
456 nsk = dccp_check_req(sk, skb, req);
461 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
462 iph->saddr, dh->dccph_sport,
463 iph->daddr, dh->dccph_dport,
466 if (nsk->sk_state != DCCP_TIME_WAIT) {
470 inet_twsk_put(inet_twsk(nsk));
477 static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
481 const struct iphdr *iph = ip_hdr(skb);
482 struct flowi4 fl4 = {
483 .flowi4_oif = inet_iif(skb),
486 .flowi4_tos = RT_CONN_FLAGS(sk),
487 .flowi4_proto = sk->sk_protocol,
488 .fl4_sport = dccp_hdr(skb)->dccph_dport,
489 .fl4_dport = dccp_hdr(skb)->dccph_sport,
492 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
493 rt = ip_route_output_flow(net, &fl4, sk);
495 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
502 static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req)
506 struct dst_entry *dst;
509 dst = inet_csk_route_req(sk, &fl4, req);
513 skb = dccp_make_response(sk, dst, req);
515 const struct inet_request_sock *ireq = inet_rsk(req);
516 struct dccp_hdr *dh = dccp_hdr(skb);
518 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr,
520 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
523 err = net_xmit_eval(err);
531 static void dccp_v4_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
534 const struct iphdr *rxiph;
536 struct dst_entry *dst;
537 struct net *net = dev_net(skb_dst(rxskb)->dev);
538 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
540 /* Never send a reset in response to a reset. */
541 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
544 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
547 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
551 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
555 rxiph = ip_hdr(rxskb);
556 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
558 skb_dst_set(skb, dst_clone(dst));
560 bh_lock_sock(ctl_sk);
561 err = ip_build_and_send_pkt(skb, ctl_sk,
562 rxiph->daddr, rxiph->saddr, NULL);
563 bh_unlock_sock(ctl_sk);
565 if (net_xmit_eval(err) == 0) {
566 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
567 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
573 static void dccp_v4_reqsk_destructor(struct request_sock *req)
575 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
576 kfree(inet_rsk(req)->opt);
579 void dccp_syn_ack_timeout(const struct request_sock *req)
582 EXPORT_SYMBOL(dccp_syn_ack_timeout);
584 static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
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,
591 .syn_ack_timeout = dccp_syn_ack_timeout,
594 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
596 struct inet_request_sock *ireq;
597 struct request_sock *req;
598 struct dccp_request_sock *dreq;
599 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
600 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
602 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
603 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
604 return 0; /* discard, don't send a reset here */
606 if (dccp_bad_service_code(sk, service)) {
607 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
611 * TW buckets are converted to open requests without
612 * limitations, they conserve resources and peer is
613 * evidently real one.
615 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
616 if (inet_csk_reqsk_queue_is_full(sk))
620 * Accept backlog is full. If we have already queued enough
621 * of warm entries in syn queue, drop request. It is better than
622 * clogging syn queue with openreqs with exponentially increasing
625 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
628 req = inet_reqsk_alloc(&dccp_request_sock_ops, sk);
632 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
635 dreq = dccp_rsk(req);
636 if (dccp_parse_options(sk, dreq, skb))
639 if (security_inet_conn_request(sk, skb, req))
642 ireq = inet_rsk(req);
643 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
644 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
645 ireq->ireq_family = AF_INET;
646 ireq->ir_iif = sk->sk_bound_dev_if;
649 * Step 3: Process LISTEN state
651 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
653 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
655 dreq->dreq_isr = dcb->dccpd_seq;
656 dreq->dreq_gsr = dreq->dreq_isr;
657 dreq->dreq_iss = dccp_v4_init_sequence(skb);
658 dreq->dreq_gss = dreq->dreq_iss;
659 dreq->dreq_service = service;
661 if (dccp_v4_send_response(sk, req))
664 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
670 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
673 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
675 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
677 struct dccp_hdr *dh = dccp_hdr(skb);
679 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
680 if (dccp_rcv_established(sk, skb, dh, skb->len))
686 * Step 3: Process LISTEN state
687 * If P.type == Request or P contains a valid Init Cookie option,
688 * (* Must scan the packet's options to check for Init
689 * Cookies. Only Init Cookies are processed here,
690 * however; other options are processed in Step 8. This
691 * scan need only be performed if the endpoint uses Init
693 * (* Generate a new socket and switch to that socket *)
694 * Set S := new socket for this port pair
696 * Choose S.ISS (initial seqno) or set from Init Cookies
697 * Initialize S.GAR := S.ISS
698 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
699 * Continue with S.state == RESPOND
700 * (* A Response packet will be generated in Step 11 *)
702 * Generate Reset(No Connection) unless P.type == Reset
703 * Drop packet and return
705 * NOTE: the check for the packet types is done in
706 * dccp_rcv_state_process
708 if (sk->sk_state == DCCP_LISTEN) {
709 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
715 if (dccp_child_process(sk, nsk, skb))
721 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
726 dccp_v4_ctl_send_reset(sk, skb);
731 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
734 * dccp_invalid_packet - check for malformed packets
735 * Implements RFC 4340, 8.5: Step 1: Check header basics
736 * Packets that fail these checks are ignored and do not receive Resets.
738 int dccp_invalid_packet(struct sk_buff *skb)
740 const struct dccp_hdr *dh;
743 if (skb->pkt_type != PACKET_HOST)
746 /* If the packet is shorter than 12 bytes, drop packet and return */
747 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
748 DCCP_WARN("pskb_may_pull failed\n");
754 /* If P.type is not understood, drop packet and return */
755 if (dh->dccph_type >= DCCP_PKT_INVALID) {
756 DCCP_WARN("invalid packet type\n");
761 * If P.Data Offset is too small for packet type, drop packet and return
763 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
764 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
768 * If P.Data Offset is too too large for packet, drop packet and return
770 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
771 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
776 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
777 * has short sequence numbers), drop packet and return
779 if ((dh->dccph_type < DCCP_PKT_DATA ||
780 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
781 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
782 dccp_packet_name(dh->dccph_type));
787 * If P.CsCov is too large for the packet size, drop packet and return.
788 * This must come _before_ checksumming (not as RFC 4340 suggests).
790 cscov = dccp_csum_coverage(skb);
791 if (cscov > skb->len) {
792 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
793 dh->dccph_cscov, skb->len);
797 /* If header checksum is incorrect, drop packet and return.
798 * (This step is completed in the AF-dependent functions.) */
799 skb->csum = skb_checksum(skb, 0, cscov, 0);
803 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
805 /* this is called when real data arrives */
806 static int dccp_v4_rcv(struct sk_buff *skb)
808 const struct dccp_hdr *dh;
809 const struct iphdr *iph;
813 /* Step 1: Check header basics */
815 if (dccp_invalid_packet(skb))
819 /* Step 1: If header checksum is incorrect, drop packet and return */
820 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
821 DCCP_WARN("dropped packet with invalid checksum\n");
827 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
828 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
830 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
831 dccp_packet_name(dh->dccph_type),
832 &iph->saddr, ntohs(dh->dccph_sport),
833 &iph->daddr, ntohs(dh->dccph_dport),
834 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
836 if (dccp_packet_without_ack(skb)) {
837 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
838 dccp_pr_debug_cat("\n");
840 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
841 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
842 DCCP_SKB_CB(skb)->dccpd_ack_seq);
846 * Look up flow ID in table and get corresponding socket */
847 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
848 dh->dccph_sport, dh->dccph_dport);
854 dccp_pr_debug("failed to look up flow ID in table and "
855 "get corresponding socket\n");
861 * ... or S.state == TIMEWAIT,
862 * Generate Reset(No Connection) unless P.type == Reset
863 * Drop packet and return
865 if (sk->sk_state == DCCP_TIME_WAIT) {
866 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
867 inet_twsk_put(inet_twsk(sk));
872 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
873 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
874 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
876 min_cov = dccp_sk(sk)->dccps_pcrlen;
877 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
878 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
879 dh->dccph_cscov, min_cov);
880 /* FIXME: "Such packets SHOULD be reported using Data Dropped
881 * options (Section 11.7) with Drop Code 0, Protocol
883 goto discard_and_relse;
886 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
887 goto discard_and_relse;
890 return sk_receive_skb(sk, skb, 1);
893 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
898 * Generate Reset(No Connection) unless P.type == Reset
899 * Drop packet and return
901 if (dh->dccph_type != DCCP_PKT_RESET) {
902 DCCP_SKB_CB(skb)->dccpd_reset_code =
903 DCCP_RESET_CODE_NO_CONNECTION;
904 dccp_v4_ctl_send_reset(sk, skb);
916 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
917 .queue_xmit = ip_queue_xmit,
918 .send_check = dccp_v4_send_check,
919 .rebuild_header = inet_sk_rebuild_header,
920 .conn_request = dccp_v4_conn_request,
921 .syn_recv_sock = dccp_v4_request_recv_sock,
922 .net_header_len = sizeof(struct iphdr),
923 .setsockopt = ip_setsockopt,
924 .getsockopt = ip_getsockopt,
925 .addr2sockaddr = inet_csk_addr2sockaddr,
926 .sockaddr_len = sizeof(struct sockaddr_in),
927 .bind_conflict = inet_csk_bind_conflict,
929 .compat_setsockopt = compat_ip_setsockopt,
930 .compat_getsockopt = compat_ip_getsockopt,
934 static int dccp_v4_init_sock(struct sock *sk)
936 static __u8 dccp_v4_ctl_sock_initialized;
937 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
940 if (unlikely(!dccp_v4_ctl_sock_initialized))
941 dccp_v4_ctl_sock_initialized = 1;
942 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
948 static struct timewait_sock_ops dccp_timewait_sock_ops = {
949 .twsk_obj_size = sizeof(struct inet_timewait_sock),
952 static struct proto dccp_v4_prot = {
954 .owner = THIS_MODULE,
956 .connect = dccp_v4_connect,
957 .disconnect = dccp_disconnect,
959 .init = dccp_v4_init_sock,
960 .setsockopt = dccp_setsockopt,
961 .getsockopt = dccp_getsockopt,
962 .sendmsg = dccp_sendmsg,
963 .recvmsg = dccp_recvmsg,
964 .backlog_rcv = dccp_v4_do_rcv,
966 .unhash = inet_unhash,
967 .accept = inet_csk_accept,
968 .get_port = inet_csk_get_port,
969 .shutdown = dccp_shutdown,
970 .destroy = dccp_destroy_sock,
971 .orphan_count = &dccp_orphan_count,
972 .max_header = MAX_DCCP_HEADER,
973 .obj_size = sizeof(struct dccp_sock),
974 .slab_flags = SLAB_DESTROY_BY_RCU,
975 .rsk_prot = &dccp_request_sock_ops,
976 .twsk_prot = &dccp_timewait_sock_ops,
977 .h.hashinfo = &dccp_hashinfo,
979 .compat_setsockopt = compat_dccp_setsockopt,
980 .compat_getsockopt = compat_dccp_getsockopt,
984 static const struct net_protocol dccp_v4_protocol = {
985 .handler = dccp_v4_rcv,
986 .err_handler = dccp_v4_err,
989 .icmp_strict_tag_validation = 1,
992 static const struct proto_ops inet_dccp_ops = {
994 .owner = THIS_MODULE,
995 .release = inet_release,
997 .connect = inet_stream_connect,
998 .socketpair = sock_no_socketpair,
999 .accept = inet_accept,
1000 .getname = inet_getname,
1001 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1003 .ioctl = inet_ioctl,
1004 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1005 .listen = inet_dccp_listen,
1006 .shutdown = inet_shutdown,
1007 .setsockopt = sock_common_setsockopt,
1008 .getsockopt = sock_common_getsockopt,
1009 .sendmsg = inet_sendmsg,
1010 .recvmsg = sock_common_recvmsg,
1011 .mmap = sock_no_mmap,
1012 .sendpage = sock_no_sendpage,
1013 #ifdef CONFIG_COMPAT
1014 .compat_setsockopt = compat_sock_common_setsockopt,
1015 .compat_getsockopt = compat_sock_common_getsockopt,
1019 static struct inet_protosw dccp_v4_protosw = {
1021 .protocol = IPPROTO_DCCP,
1022 .prot = &dccp_v4_prot,
1023 .ops = &inet_dccp_ops,
1024 .flags = INET_PROTOSW_ICSK,
1027 static int __net_init dccp_v4_init_net(struct net *net)
1029 if (dccp_hashinfo.bhash == NULL)
1030 return -ESOCKTNOSUPPORT;
1032 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1033 SOCK_DCCP, IPPROTO_DCCP, net);
1036 static void __net_exit dccp_v4_exit_net(struct net *net)
1038 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1041 static struct pernet_operations dccp_v4_ops = {
1042 .init = dccp_v4_init_net,
1043 .exit = dccp_v4_exit_net,
1046 static int __init dccp_v4_init(void)
1048 int err = proto_register(&dccp_v4_prot, 1);
1053 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1055 goto out_proto_unregister;
1057 inet_register_protosw(&dccp_v4_protosw);
1059 err = register_pernet_subsys(&dccp_v4_ops);
1061 goto out_destroy_ctl_sock;
1064 out_destroy_ctl_sock:
1065 inet_unregister_protosw(&dccp_v4_protosw);
1066 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1067 out_proto_unregister:
1068 proto_unregister(&dccp_v4_prot);
1072 static void __exit dccp_v4_exit(void)
1074 unregister_pernet_subsys(&dccp_v4_ops);
1075 inet_unregister_protosw(&dccp_v4_protosw);
1076 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1077 proto_unregister(&dccp_v4_prot);
1080 module_init(dccp_v4_init);
1081 module_exit(dccp_v4_exit);
1084 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1085 * values directly, Also cover the case where the protocol is not specified,
1086 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1088 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1089 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1090 MODULE_LICENSE("GPL");
1091 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1092 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");