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>
36 * The per-net dccp.v4_ctl_sk socket is used for responding to
37 * the Out-of-the-blue (OOTB) packets. A control sock will be created
38 * for this socket at the initialization time.
41 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
43 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
44 struct inet_sock *inet = inet_sk(sk);
45 struct dccp_sock *dp = dccp_sk(sk);
46 __be16 orig_sport, orig_dport;
47 __be32 daddr, nexthop;
51 struct ip_options_rcu *inet_opt;
53 dp->dccps_role = DCCP_ROLE_CLIENT;
55 if (addr_len < sizeof(struct sockaddr_in))
58 if (usin->sin_family != AF_INET)
61 nexthop = daddr = usin->sin_addr.s_addr;
63 inet_opt = rcu_dereference_protected(inet->inet_opt,
64 sock_owned_by_user(sk));
65 if (inet_opt != NULL && inet_opt->opt.srr) {
68 nexthop = inet_opt->opt.faddr;
71 orig_sport = inet->inet_sport;
72 orig_dport = usin->sin_port;
73 fl4 = &inet->cork.fl.u.ip4;
74 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
75 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
77 orig_sport, orig_dport, sk, true);
81 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
86 if (inet_opt == NULL || !inet_opt->opt.srr)
89 if (inet->inet_saddr == 0)
90 inet->inet_saddr = fl4->saddr;
91 inet->inet_rcv_saddr = inet->inet_saddr;
93 inet->inet_dport = usin->sin_port;
94 inet->inet_daddr = 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);
116 /* OK, now commit destination to socket. */
117 sk_setup_caps(sk, &rt->dst);
119 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
123 inet->inet_id = dp->dccps_iss ^ jiffies;
125 err = dccp_connect(sk);
133 * This unhashes the socket and releases the local port, if necessary.
135 dccp_set_state(sk, DCCP_CLOSED);
137 sk->sk_route_caps = 0;
138 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 /* We don't check in the destentry if pmtu discovery is forbidden
163 * on this route. We just assume that no packet_to_big packets
164 * are send back when pmtu discovery is not active.
165 * There is a small race when the user changes this flag in the
166 * route, but I think that's acceptable.
168 if ((dst = __sk_dst_check(sk, 0)) == NULL)
171 dst->ops->update_pmtu(dst, mtu);
173 /* Something is about to be wrong... Remember soft error
174 * for the case, if this connection will not able to recover.
176 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
177 sk->sk_err_soft = EMSGSIZE;
181 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
182 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
183 dccp_sync_mss(sk, mtu);
186 * From RFC 4340, sec. 14.1:
188 * DCCP-Sync packets are the best choice for upward
189 * probing, since DCCP-Sync probes do not risk application
192 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
193 } /* else let the usual retransmit timer handle it */
197 * This routine is called by the ICMP module when it gets some sort of error
198 * condition. If err < 0 then the socket should be closed and the error
199 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
200 * After adjustment header points to the first 8 bytes of the tcp header. We
201 * need to find the appropriate port.
203 * The locking strategy used here is very "optimistic". When someone else
204 * accesses the socket the ICMP is just dropped and for some paths there is no
205 * check at all. A more general error queue to queue errors for later handling
206 * is probably better.
208 static void dccp_v4_err(struct sk_buff *skb, u32 info)
210 const struct iphdr *iph = (struct iphdr *)skb->data;
211 const u8 offset = iph->ihl << 2;
212 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
213 struct dccp_sock *dp;
214 struct inet_sock *inet;
215 const int type = icmp_hdr(skb)->type;
216 const int code = icmp_hdr(skb)->code;
220 struct net *net = dev_net(skb->dev);
222 if (skb->len < offset + sizeof(*dh) ||
223 skb->len < offset + __dccp_basic_hdr_len(dh)) {
224 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
228 sk = inet_lookup(net, &dccp_hashinfo,
229 iph->daddr, dh->dccph_dport,
230 iph->saddr, dh->dccph_sport, inet_iif(skb));
232 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
236 if (sk->sk_state == DCCP_TIME_WAIT) {
237 inet_twsk_put(inet_twsk(sk));
242 /* If too many ICMPs get dropped on busy
243 * servers this needs to be solved differently.
245 if (sock_owned_by_user(sk))
246 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
248 if (sk->sk_state == DCCP_CLOSED)
252 seq = dccp_hdr_seq(dh);
253 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
254 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
255 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
260 case ICMP_SOURCE_QUENCH:
261 /* Just silently ignore these. */
263 case ICMP_PARAMETERPROB:
266 case ICMP_DEST_UNREACH:
267 if (code > NR_ICMP_UNREACH)
270 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
271 if (!sock_owned_by_user(sk))
272 dccp_do_pmtu_discovery(sk, iph, info);
276 err = icmp_err_convert[code].errno;
278 case ICMP_TIME_EXCEEDED:
285 switch (sk->sk_state) {
286 struct request_sock *req , **prev;
288 if (sock_owned_by_user(sk))
290 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
291 iph->daddr, iph->saddr);
296 * ICMPs are not backlogged, hence we cannot get an established
301 if (seq != dccp_rsk(req)->dreq_iss) {
302 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
306 * Still in RESPOND, just remove it silently.
307 * There is no good way to pass the error to the newly
308 * created socket, and POSIX does not want network
309 * errors returned from accept().
311 inet_csk_reqsk_queue_drop(sk, req, prev);
314 case DCCP_REQUESTING:
316 if (!sock_owned_by_user(sk)) {
317 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
320 sk->sk_error_report(sk);
324 sk->sk_err_soft = err;
328 /* If we've already connected we will keep trying
329 * until we time out, or the user gives up.
331 * rfc1122 4.2.3.9 allows to consider as hard errors
332 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
333 * but it is obsoleted by pmtu discovery).
335 * Note, that in modern internet, where routing is unreliable
336 * and in each dark corner broken firewalls sit, sending random
337 * errors ordered by their masters even this two messages finally lose
338 * their original sense (even Linux sends invalid PORT_UNREACHs)
340 * Now we are in compliance with RFCs.
345 if (!sock_owned_by_user(sk) && inet->recverr) {
347 sk->sk_error_report(sk);
348 } else /* Only an error on timeout */
349 sk->sk_err_soft = err;
355 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
356 __be32 src, __be32 dst)
358 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
361 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
363 const struct inet_sock *inet = inet_sk(sk);
364 struct dccp_hdr *dh = dccp_hdr(skb);
366 dccp_csum_outgoing(skb);
367 dh->dccph_checksum = dccp_v4_csum_finish(skb,
372 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
374 static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
376 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
378 dccp_hdr(skb)->dccph_dport,
379 dccp_hdr(skb)->dccph_sport);
383 * The three way handshake has completed - we got a valid ACK or DATAACK -
384 * now create the new socket.
386 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
388 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
389 struct request_sock *req,
390 struct dst_entry *dst)
392 struct inet_request_sock *ireq;
393 struct inet_sock *newinet;
396 if (sk_acceptq_is_full(sk))
399 newsk = dccp_create_openreq_child(sk, req, skb);
403 newinet = inet_sk(newsk);
404 ireq = inet_rsk(req);
405 newinet->inet_daddr = ireq->rmt_addr;
406 newinet->inet_rcv_saddr = ireq->loc_addr;
407 newinet->inet_saddr = ireq->loc_addr;
408 newinet->inet_opt = ireq->opt;
410 newinet->mc_index = inet_iif(skb);
411 newinet->mc_ttl = ip_hdr(skb)->ttl;
412 newinet->inet_id = jiffies;
414 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
417 sk_setup_caps(newsk, dst);
419 dccp_sync_mss(newsk, dst_mtu(dst));
421 if (__inet_inherit_port(sk, newsk) < 0)
423 __inet_hash_nolisten(newsk, NULL);
428 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
432 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
439 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
441 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
443 const struct dccp_hdr *dh = dccp_hdr(skb);
444 const struct iphdr *iph = ip_hdr(skb);
446 struct request_sock **prev;
447 /* Find possible connection requests. */
448 struct request_sock *req = inet_csk_search_req(sk, &prev,
450 iph->saddr, iph->daddr);
452 return dccp_check_req(sk, skb, req, prev);
454 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
455 iph->saddr, dh->dccph_sport,
456 iph->daddr, dh->dccph_dport,
459 if (nsk->sk_state != DCCP_TIME_WAIT) {
463 inet_twsk_put(inet_twsk(nsk));
470 static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
474 struct flowi4 fl4 = {
475 .flowi4_oif = skb_rtable(skb)->rt_iif,
476 .daddr = ip_hdr(skb)->saddr,
477 .saddr = ip_hdr(skb)->daddr,
478 .flowi4_tos = RT_CONN_FLAGS(sk),
479 .flowi4_proto = sk->sk_protocol,
480 .fl4_sport = dccp_hdr(skb)->dccph_dport,
481 .fl4_dport = dccp_hdr(skb)->dccph_sport,
484 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
485 rt = ip_route_output_flow(net, &fl4, sk);
487 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
494 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
495 struct request_values *rv_unused)
499 struct dst_entry *dst;
501 dst = inet_csk_route_req(sk, req);
505 skb = dccp_make_response(sk, dst, req);
507 const struct inet_request_sock *ireq = inet_rsk(req);
508 struct dccp_hdr *dh = dccp_hdr(skb);
510 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
512 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
515 err = net_xmit_eval(err);
523 static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
526 const struct iphdr *rxiph;
528 struct dst_entry *dst;
529 struct net *net = dev_net(skb_dst(rxskb)->dev);
530 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
532 /* Never send a reset in response to a reset. */
533 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
536 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
539 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
543 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
547 rxiph = ip_hdr(rxskb);
548 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
550 skb_dst_set(skb, dst_clone(dst));
552 bh_lock_sock(ctl_sk);
553 err = ip_build_and_send_pkt(skb, ctl_sk,
554 rxiph->daddr, rxiph->saddr, NULL);
555 bh_unlock_sock(ctl_sk);
557 if (net_xmit_eval(err) == 0) {
558 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
559 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
565 static void dccp_v4_reqsk_destructor(struct request_sock *req)
567 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
568 kfree(inet_rsk(req)->opt);
571 static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
573 .obj_size = sizeof(struct dccp_request_sock),
574 .rtx_syn_ack = dccp_v4_send_response,
575 .send_ack = dccp_reqsk_send_ack,
576 .destructor = dccp_v4_reqsk_destructor,
577 .send_reset = dccp_v4_ctl_send_reset,
580 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
582 struct inet_request_sock *ireq;
583 struct request_sock *req;
584 struct dccp_request_sock *dreq;
585 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
586 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
588 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
589 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
590 return 0; /* discard, don't send a reset here */
592 if (dccp_bad_service_code(sk, service)) {
593 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
597 * TW buckets are converted to open requests without
598 * limitations, they conserve resources and peer is
599 * evidently real one.
601 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
602 if (inet_csk_reqsk_queue_is_full(sk))
606 * Accept backlog is full. If we have already queued enough
607 * of warm entries in syn queue, drop request. It is better than
608 * clogging syn queue with openreqs with exponentially increasing
611 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
614 req = inet_reqsk_alloc(&dccp_request_sock_ops);
618 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
621 dreq = dccp_rsk(req);
622 if (dccp_parse_options(sk, dreq, skb))
625 if (security_inet_conn_request(sk, skb, req))
628 ireq = inet_rsk(req);
629 ireq->loc_addr = ip_hdr(skb)->daddr;
630 ireq->rmt_addr = ip_hdr(skb)->saddr;
633 * Step 3: Process LISTEN state
635 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
637 * In fact we defer setting S.GSR, S.SWL, S.SWH to
638 * dccp_create_openreq_child.
640 dreq->dreq_isr = dcb->dccpd_seq;
641 dreq->dreq_iss = dccp_v4_init_sequence(skb);
642 dreq->dreq_service = service;
644 if (dccp_v4_send_response(sk, req, NULL))
647 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
653 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
657 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
659 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
661 struct dccp_hdr *dh = dccp_hdr(skb);
663 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
664 if (dccp_rcv_established(sk, skb, dh, skb->len))
670 * Step 3: Process LISTEN state
671 * If P.type == Request or P contains a valid Init Cookie option,
672 * (* Must scan the packet's options to check for Init
673 * Cookies. Only Init Cookies are processed here,
674 * however; other options are processed in Step 8. This
675 * scan need only be performed if the endpoint uses Init
677 * (* Generate a new socket and switch to that socket *)
678 * Set S := new socket for this port pair
680 * Choose S.ISS (initial seqno) or set from Init Cookies
681 * Initialize S.GAR := S.ISS
682 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
683 * Continue with S.state == RESPOND
684 * (* A Response packet will be generated in Step 11 *)
686 * Generate Reset(No Connection) unless P.type == Reset
687 * Drop packet and return
689 * NOTE: the check for the packet types is done in
690 * dccp_rcv_state_process
692 if (sk->sk_state == DCCP_LISTEN) {
693 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
699 if (dccp_child_process(sk, nsk, skb))
705 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
710 dccp_v4_ctl_send_reset(sk, skb);
716 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
719 * dccp_invalid_packet - check for malformed packets
720 * Implements RFC 4340, 8.5: Step 1: Check header basics
721 * Packets that fail these checks are ignored and do not receive Resets.
723 int dccp_invalid_packet(struct sk_buff *skb)
725 const struct dccp_hdr *dh;
728 if (skb->pkt_type != PACKET_HOST)
731 /* If the packet is shorter than 12 bytes, drop packet and return */
732 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
733 DCCP_WARN("pskb_may_pull failed\n");
739 /* If P.type is not understood, drop packet and return */
740 if (dh->dccph_type >= DCCP_PKT_INVALID) {
741 DCCP_WARN("invalid packet type\n");
746 * If P.Data Offset is too small for packet type, drop packet and return
748 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
749 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
753 * If P.Data Offset is too too large for packet, drop packet and return
755 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
756 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
761 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
762 * has short sequence numbers), drop packet and return
764 if ((dh->dccph_type < DCCP_PKT_DATA ||
765 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
766 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
767 dccp_packet_name(dh->dccph_type));
772 * If P.CsCov is too large for the packet size, drop packet and return.
773 * This must come _before_ checksumming (not as RFC 4340 suggests).
775 cscov = dccp_csum_coverage(skb);
776 if (cscov > skb->len) {
777 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
778 dh->dccph_cscov, skb->len);
782 /* If header checksum is incorrect, drop packet and return.
783 * (This step is completed in the AF-dependent functions.) */
784 skb->csum = skb_checksum(skb, 0, cscov, 0);
789 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
791 /* this is called when real data arrives */
792 static int dccp_v4_rcv(struct sk_buff *skb)
794 const struct dccp_hdr *dh;
795 const struct iphdr *iph;
799 /* Step 1: Check header basics */
801 if (dccp_invalid_packet(skb))
805 /* Step 1: If header checksum is incorrect, drop packet and return */
806 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
807 DCCP_WARN("dropped packet with invalid checksum\n");
813 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
814 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
816 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
817 dccp_packet_name(dh->dccph_type),
818 &iph->saddr, ntohs(dh->dccph_sport),
819 &iph->daddr, ntohs(dh->dccph_dport),
820 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
822 if (dccp_packet_without_ack(skb)) {
823 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
824 dccp_pr_debug_cat("\n");
826 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
827 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
828 DCCP_SKB_CB(skb)->dccpd_ack_seq);
832 * Look up flow ID in table and get corresponding socket */
833 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
834 dh->dccph_sport, dh->dccph_dport);
840 dccp_pr_debug("failed to look up flow ID in table and "
841 "get corresponding socket\n");
847 * ... or S.state == TIMEWAIT,
848 * Generate Reset(No Connection) unless P.type == Reset
849 * Drop packet and return
851 if (sk->sk_state == DCCP_TIME_WAIT) {
852 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
853 inet_twsk_put(inet_twsk(sk));
858 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
859 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
860 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
862 min_cov = dccp_sk(sk)->dccps_pcrlen;
863 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
864 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
865 dh->dccph_cscov, min_cov);
866 /* FIXME: "Such packets SHOULD be reported using Data Dropped
867 * options (Section 11.7) with Drop Code 0, Protocol
869 goto discard_and_relse;
872 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
873 goto discard_and_relse;
876 return sk_receive_skb(sk, skb, 1);
879 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
884 * Generate Reset(No Connection) unless P.type == Reset
885 * Drop packet and return
887 if (dh->dccph_type != DCCP_PKT_RESET) {
888 DCCP_SKB_CB(skb)->dccpd_reset_code =
889 DCCP_RESET_CODE_NO_CONNECTION;
890 dccp_v4_ctl_send_reset(sk, skb);
902 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
903 .queue_xmit = ip_queue_xmit,
904 .send_check = dccp_v4_send_check,
905 .rebuild_header = inet_sk_rebuild_header,
906 .conn_request = dccp_v4_conn_request,
907 .syn_recv_sock = dccp_v4_request_recv_sock,
908 .net_header_len = sizeof(struct iphdr),
909 .setsockopt = ip_setsockopt,
910 .getsockopt = ip_getsockopt,
911 .addr2sockaddr = inet_csk_addr2sockaddr,
912 .sockaddr_len = sizeof(struct sockaddr_in),
913 .bind_conflict = inet_csk_bind_conflict,
915 .compat_setsockopt = compat_ip_setsockopt,
916 .compat_getsockopt = compat_ip_getsockopt,
920 static int dccp_v4_init_sock(struct sock *sk)
922 static __u8 dccp_v4_ctl_sock_initialized;
923 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
926 if (unlikely(!dccp_v4_ctl_sock_initialized))
927 dccp_v4_ctl_sock_initialized = 1;
928 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
934 static struct timewait_sock_ops dccp_timewait_sock_ops = {
935 .twsk_obj_size = sizeof(struct inet_timewait_sock),
938 static struct proto dccp_v4_prot = {
940 .owner = THIS_MODULE,
942 .connect = dccp_v4_connect,
943 .disconnect = dccp_disconnect,
945 .init = dccp_v4_init_sock,
946 .setsockopt = dccp_setsockopt,
947 .getsockopt = dccp_getsockopt,
948 .sendmsg = dccp_sendmsg,
949 .recvmsg = dccp_recvmsg,
950 .backlog_rcv = dccp_v4_do_rcv,
952 .unhash = inet_unhash,
953 .accept = inet_csk_accept,
954 .get_port = inet_csk_get_port,
955 .shutdown = dccp_shutdown,
956 .destroy = dccp_destroy_sock,
957 .orphan_count = &dccp_orphan_count,
958 .max_header = MAX_DCCP_HEADER,
959 .obj_size = sizeof(struct dccp_sock),
960 .slab_flags = SLAB_DESTROY_BY_RCU,
961 .rsk_prot = &dccp_request_sock_ops,
962 .twsk_prot = &dccp_timewait_sock_ops,
963 .h.hashinfo = &dccp_hashinfo,
965 .compat_setsockopt = compat_dccp_setsockopt,
966 .compat_getsockopt = compat_dccp_getsockopt,
970 static const struct net_protocol dccp_v4_protocol = {
971 .handler = dccp_v4_rcv,
972 .err_handler = dccp_v4_err,
977 static const struct proto_ops inet_dccp_ops = {
979 .owner = THIS_MODULE,
980 .release = inet_release,
982 .connect = inet_stream_connect,
983 .socketpair = sock_no_socketpair,
984 .accept = inet_accept,
985 .getname = inet_getname,
986 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
989 /* FIXME: work on inet_listen to rename it to sock_common_listen */
990 .listen = inet_dccp_listen,
991 .shutdown = inet_shutdown,
992 .setsockopt = sock_common_setsockopt,
993 .getsockopt = sock_common_getsockopt,
994 .sendmsg = inet_sendmsg,
995 .recvmsg = sock_common_recvmsg,
996 .mmap = sock_no_mmap,
997 .sendpage = sock_no_sendpage,
999 .compat_setsockopt = compat_sock_common_setsockopt,
1000 .compat_getsockopt = compat_sock_common_getsockopt,
1004 static struct inet_protosw dccp_v4_protosw = {
1006 .protocol = IPPROTO_DCCP,
1007 .prot = &dccp_v4_prot,
1008 .ops = &inet_dccp_ops,
1010 .flags = INET_PROTOSW_ICSK,
1013 static int __net_init dccp_v4_init_net(struct net *net)
1015 if (dccp_hashinfo.bhash == NULL)
1016 return -ESOCKTNOSUPPORT;
1018 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1019 SOCK_DCCP, IPPROTO_DCCP, net);
1022 static void __net_exit dccp_v4_exit_net(struct net *net)
1024 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1027 static struct pernet_operations dccp_v4_ops = {
1028 .init = dccp_v4_init_net,
1029 .exit = dccp_v4_exit_net,
1032 static int __init dccp_v4_init(void)
1034 int err = proto_register(&dccp_v4_prot, 1);
1039 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1041 goto out_proto_unregister;
1043 inet_register_protosw(&dccp_v4_protosw);
1045 err = register_pernet_subsys(&dccp_v4_ops);
1047 goto out_destroy_ctl_sock;
1050 out_destroy_ctl_sock:
1051 inet_unregister_protosw(&dccp_v4_protosw);
1052 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1053 out_proto_unregister:
1054 proto_unregister(&dccp_v4_prot);
1058 static void __exit dccp_v4_exit(void)
1060 unregister_pernet_subsys(&dccp_v4_ops);
1061 inet_unregister_protosw(&dccp_v4_protosw);
1062 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1063 proto_unregister(&dccp_v4_prot);
1066 module_init(dccp_v4_init);
1067 module_exit(dccp_v4_exit);
1070 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1071 * values directly, Also cover the case where the protocol is not specified,
1072 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1074 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1075 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1076 MODULE_LICENSE("GPL");
1077 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1078 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");