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 lockdep_sock_is_held(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 = prandom_u32();
126 err = dccp_connect(sk);
134 * This unhashes the socket and releases the local port, if necessary.
136 dccp_set_state(sk, DCCP_CLOSED);
137 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
138 inet_reset_saddr(sk);
140 sk->sk_route_caps = 0;
141 inet->inet_dport = 0;
144 EXPORT_SYMBOL_GPL(dccp_v4_connect);
147 * This routine does path mtu discovery as defined in RFC1191.
149 static inline void dccp_do_pmtu_discovery(struct sock *sk,
150 const struct iphdr *iph,
153 struct dst_entry *dst;
154 const struct inet_sock *inet = inet_sk(sk);
155 const struct dccp_sock *dp = dccp_sk(sk);
157 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
158 * send out by Linux are always < 576bytes so they should go through
161 if (sk->sk_state == DCCP_LISTEN)
164 dst = inet_csk_update_pmtu(sk, mtu);
168 /* Something is about to be wrong... Remember soft error
169 * for the case, if this connection will not able to recover.
171 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
172 sk->sk_err_soft = EMSGSIZE;
176 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
177 ip_sk_accept_pmtu(sk) &&
178 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
179 dccp_sync_mss(sk, mtu);
182 * From RFC 4340, sec. 14.1:
184 * DCCP-Sync packets are the best choice for upward
185 * probing, since DCCP-Sync probes do not risk application
188 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
189 } /* else let the usual retransmit timer handle it */
192 static void dccp_do_redirect(struct sk_buff *skb, struct sock *sk)
194 struct dst_entry *dst = __sk_dst_check(sk, 0);
197 dst->ops->redirect(dst, sk, skb);
200 void dccp_req_err(struct sock *sk, u64 seq)
202 struct request_sock *req = inet_reqsk(sk);
203 struct net *net = sock_net(sk);
206 * 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(net, LINUX_MIB_OUTOFWINDOWICMPS);
213 * Still in RESPOND, just remove it silently.
214 * There is no good way to pass the error to the newly
215 * created socket, and POSIX does not want network
216 * errors returned from accept().
218 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;
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 (!pskb_may_pull(skb, offset + sizeof(*dh)))
252 dh = (struct dccp_hdr *)(skb->data + offset);
253 if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh)))
255 iph = (struct iphdr *)skb->data;
256 dh = (struct dccp_hdr *)(skb->data + offset);
258 sk = __inet_lookup_established(net, &dccp_hashinfo,
259 iph->daddr, dh->dccph_dport,
260 iph->saddr, ntohs(dh->dccph_sport),
263 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
267 if (sk->sk_state == DCCP_TIME_WAIT) {
268 inet_twsk_put(inet_twsk(sk));
271 seq = dccp_hdr_seq(dh);
272 if (sk->sk_state == DCCP_NEW_SYN_RECV)
273 return dccp_req_err(sk, seq);
276 /* If too many ICMPs get dropped on busy
277 * servers this needs to be solved differently.
279 if (sock_owned_by_user(sk))
280 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
282 if (sk->sk_state == DCCP_CLOSED)
286 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
287 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
288 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
294 if (!sock_owned_by_user(sk))
295 dccp_do_redirect(skb, sk);
297 case ICMP_SOURCE_QUENCH:
298 /* Just silently ignore these. */
300 case ICMP_PARAMETERPROB:
303 case ICMP_DEST_UNREACH:
304 if (code > NR_ICMP_UNREACH)
307 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
308 if (!sock_owned_by_user(sk))
309 dccp_do_pmtu_discovery(sk, iph, info);
313 err = icmp_err_convert[code].errno;
315 case ICMP_TIME_EXCEEDED:
322 switch (sk->sk_state) {
323 case DCCP_REQUESTING:
325 if (!sock_owned_by_user(sk)) {
326 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
329 sk->sk_error_report(sk);
333 sk->sk_err_soft = err;
337 /* If we've already connected we will keep trying
338 * until we time out, or the user gives up.
340 * rfc1122 4.2.3.9 allows to consider as hard errors
341 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
342 * but it is obsoleted by pmtu discovery).
344 * Note, that in modern internet, where routing is unreliable
345 * and in each dark corner broken firewalls sit, sending random
346 * errors ordered by their masters even this two messages finally lose
347 * their original sense (even Linux sends invalid PORT_UNREACHs)
349 * Now we are in compliance with RFCs.
354 if (!sock_owned_by_user(sk) && inet->recverr) {
356 sk->sk_error_report(sk);
357 } else /* Only an error on timeout */
358 sk->sk_err_soft = err;
364 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
365 __be32 src, __be32 dst)
367 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
370 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
372 const struct inet_sock *inet = inet_sk(sk);
373 struct dccp_hdr *dh = dccp_hdr(skb);
375 dccp_csum_outgoing(skb);
376 dh->dccph_checksum = dccp_v4_csum_finish(skb,
380 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
382 static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
384 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
386 dccp_hdr(skb)->dccph_dport,
387 dccp_hdr(skb)->dccph_sport);
391 * The three way handshake has completed - we got a valid ACK or DATAACK -
392 * now create the new socket.
394 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
396 struct sock *dccp_v4_request_recv_sock(const struct sock *sk,
398 struct request_sock *req,
399 struct dst_entry *dst,
400 struct request_sock *req_unhash,
403 struct inet_request_sock *ireq;
404 struct inet_sock *newinet;
407 if (sk_acceptq_is_full(sk))
410 newsk = dccp_create_openreq_child(sk, req, skb);
414 newinet = inet_sk(newsk);
415 ireq = inet_rsk(req);
416 sk_daddr_set(newsk, ireq->ir_rmt_addr);
417 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
418 newinet->inet_saddr = ireq->ir_loc_addr;
419 RCU_INIT_POINTER(newinet->inet_opt, rcu_dereference(ireq->ireq_opt));
420 newinet->mc_index = inet_iif(skb);
421 newinet->mc_ttl = ip_hdr(skb)->ttl;
422 newinet->inet_id = prandom_u32();
424 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
427 sk_setup_caps(newsk, dst);
429 dccp_sync_mss(newsk, dst_mtu(dst));
431 if (__inet_inherit_port(sk, newsk) < 0)
433 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL);
435 ireq->ireq_opt = NULL;
437 newinet->inet_opt = NULL;
441 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
445 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
448 newinet->inet_opt = NULL;
449 inet_csk_prepare_forced_close(newsk);
453 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
455 static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
459 const struct iphdr *iph = ip_hdr(skb);
460 struct flowi4 fl4 = {
461 .flowi4_oif = inet_iif(skb),
464 .flowi4_tos = RT_CONN_FLAGS(sk),
465 .flowi4_proto = sk->sk_protocol,
466 .fl4_sport = dccp_hdr(skb)->dccph_dport,
467 .fl4_dport = dccp_hdr(skb)->dccph_sport,
470 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
471 rt = ip_route_output_flow(net, &fl4, sk);
473 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
480 static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req)
484 struct dst_entry *dst;
487 dst = inet_csk_route_req(sk, &fl4, req);
491 skb = dccp_make_response(sk, dst, req);
493 const struct inet_request_sock *ireq = inet_rsk(req);
494 struct dccp_hdr *dh = dccp_hdr(skb);
496 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr,
499 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
501 rcu_dereference(ireq->ireq_opt));
503 err = net_xmit_eval(err);
511 static void dccp_v4_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
514 const struct iphdr *rxiph;
516 struct dst_entry *dst;
517 struct net *net = dev_net(skb_dst(rxskb)->dev);
518 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
520 /* Never send a reset in response to a reset. */
521 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
524 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
527 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
531 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
535 rxiph = ip_hdr(rxskb);
536 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
538 skb_dst_set(skb, dst_clone(dst));
541 bh_lock_sock(ctl_sk);
542 err = ip_build_and_send_pkt(skb, ctl_sk,
543 rxiph->daddr, rxiph->saddr, NULL);
544 bh_unlock_sock(ctl_sk);
546 if (net_xmit_eval(err) == 0) {
547 __DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
548 __DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
555 static void dccp_v4_reqsk_destructor(struct request_sock *req)
557 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
558 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
561 void dccp_syn_ack_timeout(const struct request_sock *req)
564 EXPORT_SYMBOL(dccp_syn_ack_timeout);
566 static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
568 .obj_size = sizeof(struct dccp_request_sock),
569 .rtx_syn_ack = dccp_v4_send_response,
570 .send_ack = dccp_reqsk_send_ack,
571 .destructor = dccp_v4_reqsk_destructor,
572 .send_reset = dccp_v4_ctl_send_reset,
573 .syn_ack_timeout = dccp_syn_ack_timeout,
576 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
578 struct inet_request_sock *ireq;
579 struct request_sock *req;
580 struct dccp_request_sock *dreq;
581 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
582 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
584 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
585 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
586 return 0; /* discard, don't send a reset here */
588 if (dccp_bad_service_code(sk, service)) {
589 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
593 * TW buckets are converted to open requests without
594 * limitations, they conserve resources and peer is
595 * evidently real one.
597 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
598 if (inet_csk_reqsk_queue_is_full(sk))
601 if (sk_acceptq_is_full(sk))
604 req = inet_reqsk_alloc(&dccp_request_sock_ops, sk, true);
608 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
611 dreq = dccp_rsk(req);
612 if (dccp_parse_options(sk, dreq, skb))
615 ireq = inet_rsk(req);
616 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
617 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
618 ireq->ir_mark = inet_request_mark(sk, skb);
619 ireq->ireq_family = AF_INET;
620 ireq->ir_iif = sk->sk_bound_dev_if;
622 if (security_inet_conn_request(sk, skb, req))
626 * Step 3: Process LISTEN state
628 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
630 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
632 dreq->dreq_isr = dcb->dccpd_seq;
633 dreq->dreq_gsr = dreq->dreq_isr;
634 dreq->dreq_iss = dccp_v4_init_sequence(skb);
635 dreq->dreq_gss = dreq->dreq_iss;
636 dreq->dreq_service = service;
638 if (dccp_v4_send_response(sk, req))
641 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
648 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
651 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
653 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
655 struct dccp_hdr *dh = dccp_hdr(skb);
657 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
658 if (dccp_rcv_established(sk, skb, dh, skb->len))
664 * Step 3: Process LISTEN state
665 * If P.type == Request or P contains a valid Init Cookie option,
666 * (* Must scan the packet's options to check for Init
667 * Cookies. Only Init Cookies are processed here,
668 * however; other options are processed in Step 8. This
669 * scan need only be performed if the endpoint uses Init
671 * (* Generate a new socket and switch to that socket *)
672 * Set S := new socket for this port pair
674 * Choose S.ISS (initial seqno) or set from Init Cookies
675 * Initialize S.GAR := S.ISS
676 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
677 * Continue with S.state == RESPOND
678 * (* A Response packet will be generated in Step 11 *)
680 * Generate Reset(No Connection) unless P.type == Reset
681 * Drop packet and return
683 * NOTE: the check for the packet types is done in
684 * dccp_rcv_state_process
687 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
692 dccp_v4_ctl_send_reset(sk, skb);
696 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
699 * dccp_invalid_packet - check for malformed packets
700 * Implements RFC 4340, 8.5: Step 1: Check header basics
701 * Packets that fail these checks are ignored and do not receive Resets.
703 int dccp_invalid_packet(struct sk_buff *skb)
705 const struct dccp_hdr *dh;
709 if (skb->pkt_type != PACKET_HOST)
712 /* If the packet is shorter than 12 bytes, drop packet and return */
713 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
714 DCCP_WARN("pskb_may_pull failed\n");
720 /* If P.type is not understood, drop packet and return */
721 if (dh->dccph_type >= DCCP_PKT_INVALID) {
722 DCCP_WARN("invalid packet type\n");
727 * If P.Data Offset is too small for packet type, drop packet and return
729 dccph_doff = dh->dccph_doff;
730 if (dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
731 DCCP_WARN("P.Data Offset(%u) too small\n", dccph_doff);
735 * If P.Data Offset is too too large for packet, drop packet and return
737 if (!pskb_may_pull(skb, dccph_doff * sizeof(u32))) {
738 DCCP_WARN("P.Data Offset(%u) too large\n", dccph_doff);
743 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
744 * has short sequence numbers), drop packet and return
746 if ((dh->dccph_type < DCCP_PKT_DATA ||
747 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
748 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
749 dccp_packet_name(dh->dccph_type));
754 * If P.CsCov is too large for the packet size, drop packet and return.
755 * This must come _before_ checksumming (not as RFC 4340 suggests).
757 cscov = dccp_csum_coverage(skb);
758 if (cscov > skb->len) {
759 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
760 dh->dccph_cscov, skb->len);
764 /* If header checksum is incorrect, drop packet and return.
765 * (This step is completed in the AF-dependent functions.) */
766 skb->csum = skb_checksum(skb, 0, cscov, 0);
770 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
772 /* this is called when real data arrives */
773 static int dccp_v4_rcv(struct sk_buff *skb)
775 const struct dccp_hdr *dh;
776 const struct iphdr *iph;
781 /* Step 1: Check header basics */
783 if (dccp_invalid_packet(skb))
787 /* Step 1: If header checksum is incorrect, drop packet and return */
788 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
789 DCCP_WARN("dropped packet with invalid checksum\n");
795 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
796 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
798 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
799 dccp_packet_name(dh->dccph_type),
800 &iph->saddr, ntohs(dh->dccph_sport),
801 &iph->daddr, ntohs(dh->dccph_dport),
802 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
804 if (dccp_packet_without_ack(skb)) {
805 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
806 dccp_pr_debug_cat("\n");
808 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
809 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
810 DCCP_SKB_CB(skb)->dccpd_ack_seq);
814 sk = __inet_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
815 dh->dccph_sport, dh->dccph_dport, 0, &refcounted);
817 dccp_pr_debug("failed to look up flow ID in table and "
818 "get corresponding socket\n");
824 * ... or S.state == TIMEWAIT,
825 * Generate Reset(No Connection) unless P.type == Reset
826 * Drop packet and return
828 if (sk->sk_state == DCCP_TIME_WAIT) {
829 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
830 inet_twsk_put(inet_twsk(sk));
834 if (sk->sk_state == DCCP_NEW_SYN_RECV) {
835 struct request_sock *req = inet_reqsk(sk);
838 sk = req->rsk_listener;
839 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
840 inet_csk_reqsk_queue_drop_and_put(sk, req);
845 nsk = dccp_check_req(sk, skb, req);
848 goto discard_and_relse;
852 } else if (dccp_child_process(sk, nsk, skb)) {
853 dccp_v4_ctl_send_reset(sk, skb);
854 goto discard_and_relse;
861 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
862 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
863 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
865 min_cov = dccp_sk(sk)->dccps_pcrlen;
866 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
867 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
868 dh->dccph_cscov, min_cov);
869 /* FIXME: "Such packets SHOULD be reported using Data Dropped
870 * options (Section 11.7) with Drop Code 0, Protocol
872 goto discard_and_relse;
875 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
876 goto discard_and_relse;
879 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, refcounted);
882 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
887 * Generate Reset(No Connection) unless P.type == Reset
888 * Drop packet and return
890 if (dh->dccph_type != DCCP_PKT_RESET) {
891 DCCP_SKB_CB(skb)->dccpd_reset_code =
892 DCCP_RESET_CODE_NO_CONNECTION;
893 dccp_v4_ctl_send_reset(sk, skb);
906 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
907 .queue_xmit = ip_queue_xmit,
908 .send_check = dccp_v4_send_check,
909 .rebuild_header = inet_sk_rebuild_header,
910 .conn_request = dccp_v4_conn_request,
911 .syn_recv_sock = dccp_v4_request_recv_sock,
912 .net_header_len = sizeof(struct iphdr),
913 .setsockopt = ip_setsockopt,
914 .getsockopt = ip_getsockopt,
915 .addr2sockaddr = inet_csk_addr2sockaddr,
916 .sockaddr_len = sizeof(struct sockaddr_in),
918 .compat_setsockopt = compat_ip_setsockopt,
919 .compat_getsockopt = compat_ip_getsockopt,
923 static int dccp_v4_init_sock(struct sock *sk)
925 static __u8 dccp_v4_ctl_sock_initialized;
926 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
929 if (unlikely(!dccp_v4_ctl_sock_initialized))
930 dccp_v4_ctl_sock_initialized = 1;
931 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
937 static struct timewait_sock_ops dccp_timewait_sock_ops = {
938 .twsk_obj_size = sizeof(struct inet_timewait_sock),
941 static struct proto dccp_v4_prot = {
943 .owner = THIS_MODULE,
945 .connect = dccp_v4_connect,
946 .disconnect = dccp_disconnect,
948 .init = dccp_v4_init_sock,
949 .setsockopt = dccp_setsockopt,
950 .getsockopt = dccp_getsockopt,
951 .sendmsg = dccp_sendmsg,
952 .recvmsg = dccp_recvmsg,
953 .backlog_rcv = dccp_v4_do_rcv,
955 .unhash = inet_unhash,
956 .accept = inet_csk_accept,
957 .get_port = inet_csk_get_port,
958 .shutdown = dccp_shutdown,
959 .destroy = dccp_destroy_sock,
960 .orphan_count = &dccp_orphan_count,
961 .max_header = MAX_DCCP_HEADER,
962 .obj_size = sizeof(struct dccp_sock),
963 .slab_flags = SLAB_TYPESAFE_BY_RCU,
964 .rsk_prot = &dccp_request_sock_ops,
965 .twsk_prot = &dccp_timewait_sock_ops,
966 .h.hashinfo = &dccp_hashinfo,
968 .compat_setsockopt = compat_dccp_setsockopt,
969 .compat_getsockopt = compat_dccp_getsockopt,
973 static const struct net_protocol dccp_v4_protocol = {
974 .handler = dccp_v4_rcv,
975 .err_handler = dccp_v4_err,
978 .icmp_strict_tag_validation = 1,
981 static const struct proto_ops inet_dccp_ops = {
983 .owner = THIS_MODULE,
984 .release = inet_release,
986 .connect = inet_stream_connect,
987 .socketpair = sock_no_socketpair,
988 .accept = inet_accept,
989 .getname = inet_getname,
990 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
993 /* FIXME: work on inet_listen to rename it to sock_common_listen */
994 .listen = inet_dccp_listen,
995 .shutdown = inet_shutdown,
996 .setsockopt = sock_common_setsockopt,
997 .getsockopt = sock_common_getsockopt,
998 .sendmsg = inet_sendmsg,
999 .recvmsg = sock_common_recvmsg,
1000 .mmap = sock_no_mmap,
1001 .sendpage = sock_no_sendpage,
1002 #ifdef CONFIG_COMPAT
1003 .compat_setsockopt = compat_sock_common_setsockopt,
1004 .compat_getsockopt = compat_sock_common_getsockopt,
1008 static struct inet_protosw dccp_v4_protosw = {
1010 .protocol = IPPROTO_DCCP,
1011 .prot = &dccp_v4_prot,
1012 .ops = &inet_dccp_ops,
1013 .flags = INET_PROTOSW_ICSK,
1016 static int __net_init dccp_v4_init_net(struct net *net)
1018 if (dccp_hashinfo.bhash == NULL)
1019 return -ESOCKTNOSUPPORT;
1021 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1022 SOCK_DCCP, IPPROTO_DCCP, net);
1025 static void __net_exit dccp_v4_exit_net(struct net *net)
1027 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1030 static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
1032 inet_twsk_purge(&dccp_hashinfo, AF_INET);
1035 static struct pernet_operations dccp_v4_ops = {
1036 .init = dccp_v4_init_net,
1037 .exit = dccp_v4_exit_net,
1038 .exit_batch = dccp_v4_exit_batch,
1041 static int __init dccp_v4_init(void)
1043 int err = proto_register(&dccp_v4_prot, 1);
1048 inet_register_protosw(&dccp_v4_protosw);
1050 err = register_pernet_subsys(&dccp_v4_ops);
1052 goto out_destroy_ctl_sock;
1054 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1056 goto out_proto_unregister;
1060 out_proto_unregister:
1061 unregister_pernet_subsys(&dccp_v4_ops);
1062 out_destroy_ctl_sock:
1063 inet_unregister_protosw(&dccp_v4_protosw);
1064 proto_unregister(&dccp_v4_prot);
1068 static void __exit dccp_v4_exit(void)
1070 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1071 unregister_pernet_subsys(&dccp_v4_ops);
1072 inet_unregister_protosw(&dccp_v4_protosw);
1073 proto_unregister(&dccp_v4_prot);
1076 module_init(dccp_v4_init);
1077 module_exit(dccp_v4_exit);
1080 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1081 * values directly, Also cover the case where the protocol is not specified,
1082 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1084 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1085 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1086 MODULE_LICENSE("GPL");
1087 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1088 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");