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, true);
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 inet->inet_rcv_saddr = inet->inet_saddr;
94 inet->inet_dport = usin->sin_port;
95 inet->inet_daddr = daddr;
97 inet_csk(sk)->icsk_ext_hdr_len = 0;
99 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
101 * Socket identity is still unknown (sport may be zero).
102 * However we set state to DCCP_REQUESTING and not releasing socket
103 * lock select source port, enter ourselves into the hash tables and
104 * complete initialization after this.
106 dccp_set_state(sk, DCCP_REQUESTING);
107 err = inet_hash_connect(&dccp_death_row, sk);
111 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
112 inet->inet_sport, inet->inet_dport, sk);
118 /* OK, now commit destination to socket. */
119 sk_setup_caps(sk, &rt->dst);
121 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
125 inet->inet_id = dp->dccps_iss ^ jiffies;
127 err = dccp_connect(sk);
135 * This unhashes the socket and releases the local port, if necessary.
137 dccp_set_state(sk, DCCP_CLOSED);
139 sk->sk_route_caps = 0;
140 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 /* We don't check in the destentry if pmtu discovery is forbidden
165 * on this route. We just assume that no packet_to_big packets
166 * are send back when pmtu discovery is not active.
167 * There is a small race when the user changes this flag in the
168 * route, but I think that's acceptable.
170 if ((dst = __sk_dst_check(sk, 0)) == NULL)
173 dst->ops->update_pmtu(dst, mtu);
175 /* Something is about to be wrong... Remember soft error
176 * for the case, if this connection will not able to recover.
178 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
179 sk->sk_err_soft = EMSGSIZE;
183 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
184 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
185 dccp_sync_mss(sk, mtu);
188 * From RFC 4340, sec. 14.1:
190 * DCCP-Sync packets are the best choice for upward
191 * probing, since DCCP-Sync probes do not risk application
194 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
195 } /* else let the usual retransmit timer handle it */
199 * This routine is called by the ICMP module when it gets some sort of error
200 * condition. If err < 0 then the socket should be closed and the error
201 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
202 * After adjustment header points to the first 8 bytes of the tcp header. We
203 * need to find the appropriate port.
205 * The locking strategy used here is very "optimistic". When someone else
206 * accesses the socket the ICMP is just dropped and for some paths there is no
207 * check at all. A more general error queue to queue errors for later handling
208 * is probably better.
210 static void dccp_v4_err(struct sk_buff *skb, u32 info)
212 const struct iphdr *iph = (struct iphdr *)skb->data;
213 const u8 offset = iph->ihl << 2;
214 const struct dccp_hdr *dh;
215 struct dccp_sock *dp;
216 struct inet_sock *inet;
217 const int type = icmp_hdr(skb)->type;
218 const int code = icmp_hdr(skb)->code;
222 struct net *net = dev_net(skb->dev);
224 /* Only need dccph_dport & dccph_sport which are the first
225 * 4 bytes in dccp header.
226 * Our caller (icmp_socket_deliver()) already pulled 8 bytes for us.
228 BUILD_BUG_ON(offsetof(struct dccp_hdr, dccph_sport) + sizeof(dh->dccph_sport) > 8);
229 BUILD_BUG_ON(offsetof(struct dccp_hdr, dccph_dport) + sizeof(dh->dccph_dport) > 8);
230 dh = (struct dccp_hdr *)(skb->data + offset);
232 sk = inet_lookup(net, &dccp_hashinfo,
233 iph->daddr, dh->dccph_dport,
234 iph->saddr, dh->dccph_sport, inet_iif(skb));
236 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
240 if (sk->sk_state == DCCP_TIME_WAIT) {
241 inet_twsk_put(inet_twsk(sk));
246 /* If too many ICMPs get dropped on busy
247 * servers this needs to be solved differently.
249 if (sock_owned_by_user(sk))
250 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
252 if (sk->sk_state == DCCP_CLOSED)
256 seq = dccp_hdr_seq(dh);
257 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
258 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
259 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
264 case ICMP_SOURCE_QUENCH:
265 /* Just silently ignore these. */
267 case ICMP_PARAMETERPROB:
270 case ICMP_DEST_UNREACH:
271 if (code > NR_ICMP_UNREACH)
274 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
275 if (!sock_owned_by_user(sk))
276 dccp_do_pmtu_discovery(sk, iph, info);
280 err = icmp_err_convert[code].errno;
282 case ICMP_TIME_EXCEEDED:
289 switch (sk->sk_state) {
290 struct request_sock *req , **prev;
292 if (sock_owned_by_user(sk))
294 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
295 iph->daddr, iph->saddr);
300 * ICMPs are not backlogged, hence we cannot get an established
305 if (seq != dccp_rsk(req)->dreq_iss) {
306 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
310 * Still in RESPOND, just remove it silently.
311 * There is no good way to pass the error to the newly
312 * created socket, and POSIX does not want network
313 * errors returned from accept().
315 inet_csk_reqsk_queue_drop(sk, req, prev);
318 case DCCP_REQUESTING:
320 if (!sock_owned_by_user(sk)) {
321 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
324 sk->sk_error_report(sk);
328 sk->sk_err_soft = err;
332 /* If we've already connected we will keep trying
333 * until we time out, or the user gives up.
335 * rfc1122 4.2.3.9 allows to consider as hard errors
336 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
337 * but it is obsoleted by pmtu discovery).
339 * Note, that in modern internet, where routing is unreliable
340 * and in each dark corner broken firewalls sit, sending random
341 * errors ordered by their masters even this two messages finally lose
342 * their original sense (even Linux sends invalid PORT_UNREACHs)
344 * Now we are in compliance with RFCs.
349 if (!sock_owned_by_user(sk) && inet->recverr) {
351 sk->sk_error_report(sk);
352 } else /* Only an error on timeout */
353 sk->sk_err_soft = err;
359 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
360 __be32 src, __be32 dst)
362 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
365 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
367 const struct inet_sock *inet = inet_sk(sk);
368 struct dccp_hdr *dh = dccp_hdr(skb);
370 dccp_csum_outgoing(skb);
371 dh->dccph_checksum = dccp_v4_csum_finish(skb,
376 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
378 static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
380 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
382 dccp_hdr(skb)->dccph_dport,
383 dccp_hdr(skb)->dccph_sport);
387 * The three way handshake has completed - we got a valid ACK or DATAACK -
388 * now create the new socket.
390 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
392 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
393 struct request_sock *req,
394 struct dst_entry *dst)
396 struct inet_request_sock *ireq;
397 struct inet_sock *newinet;
400 if (sk_acceptq_is_full(sk))
403 newsk = dccp_create_openreq_child(sk, req, skb);
407 newinet = inet_sk(newsk);
408 ireq = inet_rsk(req);
409 newinet->inet_daddr = ireq->rmt_addr;
410 newinet->inet_rcv_saddr = ireq->loc_addr;
411 newinet->inet_saddr = ireq->loc_addr;
412 newinet->inet_opt = ireq->opt;
414 newinet->mc_index = inet_iif(skb);
415 newinet->mc_ttl = ip_hdr(skb)->ttl;
416 newinet->inet_id = jiffies;
418 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
421 sk_setup_caps(newsk, dst);
423 dccp_sync_mss(newsk, dst_mtu(dst));
425 if (__inet_inherit_port(sk, newsk) < 0)
427 __inet_hash_nolisten(newsk, NULL);
432 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
436 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
439 inet_csk_prepare_forced_close(newsk);
444 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
446 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
448 const struct dccp_hdr *dh = dccp_hdr(skb);
449 const struct iphdr *iph = ip_hdr(skb);
451 struct request_sock **prev;
452 /* Find possible connection requests. */
453 struct request_sock *req = inet_csk_search_req(sk, &prev,
455 iph->saddr, iph->daddr);
457 return dccp_check_req(sk, skb, req, prev);
459 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
460 iph->saddr, dh->dccph_sport,
461 iph->daddr, dh->dccph_dport,
464 if (nsk->sk_state != DCCP_TIME_WAIT) {
468 inet_twsk_put(inet_twsk(nsk));
475 static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
479 struct flowi4 fl4 = {
480 .flowi4_oif = skb_rtable(skb)->rt_iif,
481 .daddr = ip_hdr(skb)->saddr,
482 .saddr = ip_hdr(skb)->daddr,
483 .flowi4_tos = RT_CONN_FLAGS(sk),
484 .flowi4_proto = sk->sk_protocol,
485 .fl4_sport = dccp_hdr(skb)->dccph_dport,
486 .fl4_dport = dccp_hdr(skb)->dccph_sport,
489 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
490 rt = ip_route_output_flow(net, &fl4, sk);
492 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
499 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
500 struct request_values *rv_unused)
504 struct dst_entry *dst;
507 dst = inet_csk_route_req(sk, &fl4, req);
511 skb = dccp_make_response(sk, dst, req);
513 const struct inet_request_sock *ireq = inet_rsk(req);
514 struct dccp_hdr *dh = dccp_hdr(skb);
516 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
518 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
521 err = net_xmit_eval(err);
529 static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
532 const struct iphdr *rxiph;
534 struct dst_entry *dst;
535 struct net *net = dev_net(skb_dst(rxskb)->dev);
536 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
538 /* Never send a reset in response to a reset. */
539 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
542 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
545 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
549 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
553 rxiph = ip_hdr(rxskb);
554 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
556 skb_dst_set(skb, dst_clone(dst));
558 bh_lock_sock(ctl_sk);
559 err = ip_build_and_send_pkt(skb, ctl_sk,
560 rxiph->daddr, rxiph->saddr, NULL);
561 bh_unlock_sock(ctl_sk);
563 if (net_xmit_eval(err) == 0) {
564 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
565 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
571 static void dccp_v4_reqsk_destructor(struct request_sock *req)
573 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
574 kfree(inet_rsk(req)->opt);
577 static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
579 .obj_size = sizeof(struct dccp_request_sock),
580 .rtx_syn_ack = dccp_v4_send_response,
581 .send_ack = dccp_reqsk_send_ack,
582 .destructor = dccp_v4_reqsk_destructor,
583 .send_reset = dccp_v4_ctl_send_reset,
586 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
588 struct inet_request_sock *ireq;
589 struct request_sock *req;
590 struct dccp_request_sock *dreq;
591 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
592 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
594 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
595 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
596 return 0; /* discard, don't send a reset here */
598 if (dccp_bad_service_code(sk, service)) {
599 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
603 * TW buckets are converted to open requests without
604 * limitations, they conserve resources and peer is
605 * evidently real one.
607 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
608 if (inet_csk_reqsk_queue_is_full(sk))
612 * Accept backlog is full. If we have already queued enough
613 * of warm entries in syn queue, drop request. It is better than
614 * clogging syn queue with openreqs with exponentially increasing
617 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
620 req = inet_reqsk_alloc(&dccp_request_sock_ops);
624 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
627 dreq = dccp_rsk(req);
628 if (dccp_parse_options(sk, dreq, skb))
631 if (security_inet_conn_request(sk, skb, req))
634 ireq = inet_rsk(req);
635 ireq->loc_addr = ip_hdr(skb)->daddr;
636 ireq->rmt_addr = ip_hdr(skb)->saddr;
639 * Step 3: Process LISTEN state
641 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
643 * In fact we defer setting S.GSR, S.SWL, S.SWH to
644 * dccp_create_openreq_child.
646 dreq->dreq_isr = dcb->dccpd_seq;
647 dreq->dreq_iss = dccp_v4_init_sequence(skb);
648 dreq->dreq_service = service;
650 if (dccp_v4_send_response(sk, req, NULL))
653 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
659 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
663 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
665 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
667 struct dccp_hdr *dh = dccp_hdr(skb);
669 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
670 if (dccp_rcv_established(sk, skb, dh, skb->len))
676 * Step 3: Process LISTEN state
677 * If P.type == Request or P contains a valid Init Cookie option,
678 * (* Must scan the packet's options to check for Init
679 * Cookies. Only Init Cookies are processed here,
680 * however; other options are processed in Step 8. This
681 * scan need only be performed if the endpoint uses Init
683 * (* Generate a new socket and switch to that socket *)
684 * Set S := new socket for this port pair
686 * Choose S.ISS (initial seqno) or set from Init Cookies
687 * Initialize S.GAR := S.ISS
688 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
689 * Continue with S.state == RESPOND
690 * (* A Response packet will be generated in Step 11 *)
692 * Generate Reset(No Connection) unless P.type == Reset
693 * Drop packet and return
695 * NOTE: the check for the packet types is done in
696 * dccp_rcv_state_process
698 if (sk->sk_state == DCCP_LISTEN) {
699 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
705 if (dccp_child_process(sk, nsk, skb))
711 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
716 dccp_v4_ctl_send_reset(sk, skb);
722 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
725 * dccp_invalid_packet - check for malformed packets
726 * Implements RFC 4340, 8.5: Step 1: Check header basics
727 * Packets that fail these checks are ignored and do not receive Resets.
729 int dccp_invalid_packet(struct sk_buff *skb)
731 const struct dccp_hdr *dh;
735 if (skb->pkt_type != PACKET_HOST)
738 /* If the packet is shorter than 12 bytes, drop packet and return */
739 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
740 DCCP_WARN("pskb_may_pull failed\n");
746 /* If P.type is not understood, drop packet and return */
747 if (dh->dccph_type >= DCCP_PKT_INVALID) {
748 DCCP_WARN("invalid packet type\n");
753 * If P.Data Offset is too small for packet type, drop packet and return
755 dccph_doff = dh->dccph_doff;
756 if (dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
757 DCCP_WARN("P.Data Offset(%u) too small\n", dccph_doff);
761 * If P.Data Offset is too too large for packet, drop packet and return
763 if (!pskb_may_pull(skb, dccph_doff * sizeof(u32))) {
764 DCCP_WARN("P.Data Offset(%u) too large\n", dccph_doff);
769 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
770 * has short sequence numbers), drop packet and return
772 if ((dh->dccph_type < DCCP_PKT_DATA ||
773 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
774 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
775 dccp_packet_name(dh->dccph_type));
780 * If P.CsCov is too large for the packet size, drop packet and return.
781 * This must come _before_ checksumming (not as RFC 4340 suggests).
783 cscov = dccp_csum_coverage(skb);
784 if (cscov > skb->len) {
785 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
786 dh->dccph_cscov, skb->len);
790 /* If header checksum is incorrect, drop packet and return.
791 * (This step is completed in the AF-dependent functions.) */
792 skb->csum = skb_checksum(skb, 0, cscov, 0);
797 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
799 /* this is called when real data arrives */
800 static int dccp_v4_rcv(struct sk_buff *skb)
802 const struct dccp_hdr *dh;
803 const struct iphdr *iph;
807 /* Step 1: Check header basics */
809 if (dccp_invalid_packet(skb))
813 /* Step 1: If header checksum is incorrect, drop packet and return */
814 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
815 DCCP_WARN("dropped packet with invalid checksum\n");
821 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
822 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
824 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
825 dccp_packet_name(dh->dccph_type),
826 &iph->saddr, ntohs(dh->dccph_sport),
827 &iph->daddr, ntohs(dh->dccph_dport),
828 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
830 if (dccp_packet_without_ack(skb)) {
831 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
832 dccp_pr_debug_cat("\n");
834 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
835 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
836 DCCP_SKB_CB(skb)->dccpd_ack_seq);
840 * Look up flow ID in table and get corresponding socket */
841 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
842 dh->dccph_sport, dh->dccph_dport);
848 dccp_pr_debug("failed to look up flow ID in table and "
849 "get corresponding socket\n");
855 * ... or S.state == TIMEWAIT,
856 * Generate Reset(No Connection) unless P.type == Reset
857 * Drop packet and return
859 if (sk->sk_state == DCCP_TIME_WAIT) {
860 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
861 inet_twsk_put(inet_twsk(sk));
866 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
867 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
868 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
870 min_cov = dccp_sk(sk)->dccps_pcrlen;
871 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
872 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
873 dh->dccph_cscov, min_cov);
874 /* FIXME: "Such packets SHOULD be reported using Data Dropped
875 * options (Section 11.7) with Drop Code 0, Protocol
877 goto discard_and_relse;
880 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
881 goto discard_and_relse;
884 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4);
887 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
892 * Generate Reset(No Connection) unless P.type == Reset
893 * Drop packet and return
895 if (dh->dccph_type != DCCP_PKT_RESET) {
896 DCCP_SKB_CB(skb)->dccpd_reset_code =
897 DCCP_RESET_CODE_NO_CONNECTION;
898 dccp_v4_ctl_send_reset(sk, skb);
910 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
911 .queue_xmit = ip_queue_xmit,
912 .send_check = dccp_v4_send_check,
913 .rebuild_header = inet_sk_rebuild_header,
914 .conn_request = dccp_v4_conn_request,
915 .syn_recv_sock = dccp_v4_request_recv_sock,
916 .net_header_len = sizeof(struct iphdr),
917 .setsockopt = ip_setsockopt,
918 .getsockopt = ip_getsockopt,
919 .addr2sockaddr = inet_csk_addr2sockaddr,
920 .sockaddr_len = sizeof(struct sockaddr_in),
921 .bind_conflict = inet_csk_bind_conflict,
923 .compat_setsockopt = compat_ip_setsockopt,
924 .compat_getsockopt = compat_ip_getsockopt,
928 static int dccp_v4_init_sock(struct sock *sk)
930 static __u8 dccp_v4_ctl_sock_initialized;
931 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
934 if (unlikely(!dccp_v4_ctl_sock_initialized))
935 dccp_v4_ctl_sock_initialized = 1;
936 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
942 static struct timewait_sock_ops dccp_timewait_sock_ops = {
943 .twsk_obj_size = sizeof(struct inet_timewait_sock),
946 static struct proto dccp_v4_prot = {
948 .owner = THIS_MODULE,
950 .connect = dccp_v4_connect,
951 .disconnect = dccp_disconnect,
953 .init = dccp_v4_init_sock,
954 .setsockopt = dccp_setsockopt,
955 .getsockopt = dccp_getsockopt,
956 .sendmsg = dccp_sendmsg,
957 .recvmsg = dccp_recvmsg,
958 .backlog_rcv = dccp_v4_do_rcv,
960 .unhash = inet_unhash,
961 .accept = inet_csk_accept,
962 .get_port = inet_csk_get_port,
963 .shutdown = dccp_shutdown,
964 .destroy = dccp_destroy_sock,
965 .orphan_count = &dccp_orphan_count,
966 .max_header = MAX_DCCP_HEADER,
967 .obj_size = sizeof(struct dccp_sock),
968 .slab_flags = SLAB_DESTROY_BY_RCU,
969 .rsk_prot = &dccp_request_sock_ops,
970 .twsk_prot = &dccp_timewait_sock_ops,
971 .h.hashinfo = &dccp_hashinfo,
973 .compat_setsockopt = compat_dccp_setsockopt,
974 .compat_getsockopt = compat_dccp_getsockopt,
978 static const struct net_protocol dccp_v4_protocol = {
979 .handler = dccp_v4_rcv,
980 .err_handler = dccp_v4_err,
985 static const struct proto_ops inet_dccp_ops = {
987 .owner = THIS_MODULE,
988 .release = inet_release,
990 .connect = inet_stream_connect,
991 .socketpair = sock_no_socketpair,
992 .accept = inet_accept,
993 .getname = inet_getname,
994 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
997 /* FIXME: work on inet_listen to rename it to sock_common_listen */
998 .listen = inet_dccp_listen,
999 .shutdown = inet_shutdown,
1000 .setsockopt = sock_common_setsockopt,
1001 .getsockopt = sock_common_getsockopt,
1002 .sendmsg = inet_sendmsg,
1003 .recvmsg = sock_common_recvmsg,
1004 .mmap = sock_no_mmap,
1005 .sendpage = sock_no_sendpage,
1006 #ifdef CONFIG_COMPAT
1007 .compat_setsockopt = compat_sock_common_setsockopt,
1008 .compat_getsockopt = compat_sock_common_getsockopt,
1012 static struct inet_protosw dccp_v4_protosw = {
1014 .protocol = IPPROTO_DCCP,
1015 .prot = &dccp_v4_prot,
1016 .ops = &inet_dccp_ops,
1018 .flags = INET_PROTOSW_ICSK,
1021 static int __net_init dccp_v4_init_net(struct net *net)
1023 if (dccp_hashinfo.bhash == NULL)
1024 return -ESOCKTNOSUPPORT;
1026 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1027 SOCK_DCCP, IPPROTO_DCCP, net);
1030 static void __net_exit dccp_v4_exit_net(struct net *net)
1032 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1035 static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
1037 inet_twsk_purge(&dccp_hashinfo, &dccp_death_row, AF_INET);
1040 static struct pernet_operations dccp_v4_ops = {
1041 .init = dccp_v4_init_net,
1042 .exit = dccp_v4_exit_net,
1043 .exit_batch = dccp_v4_exit_batch,
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");