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 struct inet_sock *inet = inet_sk(sk);
44 struct dccp_sock *dp = dccp_sk(sk);
45 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
47 __be32 daddr, nexthop;
51 dp->dccps_role = DCCP_ROLE_CLIENT;
53 if (addr_len < sizeof(struct sockaddr_in))
56 if (usin->sin_family != AF_INET)
59 nexthop = daddr = usin->sin_addr.s_addr;
60 if (inet->opt != NULL && inet->opt->srr) {
63 nexthop = inet->opt->faddr;
66 tmp = ip_route_connect(&rt, nexthop, inet->inet_saddr,
67 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
69 inet->inet_sport, usin->sin_port, sk, 1);
73 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
78 if (inet->opt == NULL || !inet->opt->srr)
81 if (inet->inet_saddr == 0)
82 inet->inet_saddr = rt->rt_src;
83 inet->inet_rcv_saddr = inet->inet_saddr;
85 inet->inet_dport = usin->sin_port;
86 inet->inet_daddr = daddr;
88 inet_csk(sk)->icsk_ext_hdr_len = 0;
89 if (inet->opt != NULL)
90 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
92 * Socket identity is still unknown (sport may be zero).
93 * However we set state to DCCP_REQUESTING and not releasing socket
94 * lock select source port, enter ourselves into the hash tables and
95 * complete initialization after this.
97 dccp_set_state(sk, DCCP_REQUESTING);
98 err = inet_hash_connect(&dccp_death_row, sk);
102 err = ip_route_newports(&rt, IPPROTO_DCCP, inet->inet_sport,
103 inet->inet_dport, sk);
107 /* OK, now commit destination to socket. */
108 sk_setup_caps(sk, &rt->dst);
110 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
114 inet->inet_id = dp->dccps_iss ^ jiffies;
116 err = dccp_connect(sk);
124 * This unhashes the socket and releases the local port, if necessary.
126 dccp_set_state(sk, DCCP_CLOSED);
128 sk->sk_route_caps = 0;
129 inet->inet_dport = 0;
133 EXPORT_SYMBOL_GPL(dccp_v4_connect);
136 * This routine does path mtu discovery as defined in RFC1191.
138 static inline void dccp_do_pmtu_discovery(struct sock *sk,
139 const struct iphdr *iph,
142 struct dst_entry *dst;
143 const struct inet_sock *inet = inet_sk(sk);
144 const struct dccp_sock *dp = dccp_sk(sk);
146 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
147 * send out by Linux are always < 576bytes so they should go through
150 if (sk->sk_state == DCCP_LISTEN)
153 /* We don't check in the destentry if pmtu discovery is forbidden
154 * on this route. We just assume that no packet_to_big packets
155 * are send back when pmtu discovery is not active.
156 * There is a small race when the user changes this flag in the
157 * route, but I think that's acceptable.
159 if ((dst = __sk_dst_check(sk, 0)) == NULL)
162 dst->ops->update_pmtu(dst, mtu);
164 /* Something is about to be wrong... Remember soft error
165 * for the case, if this connection will not able to recover.
167 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
168 sk->sk_err_soft = EMSGSIZE;
172 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
173 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
174 dccp_sync_mss(sk, mtu);
177 * From RFC 4340, sec. 14.1:
179 * DCCP-Sync packets are the best choice for upward
180 * probing, since DCCP-Sync probes do not risk application
183 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
184 } /* else let the usual retransmit timer handle it */
188 * This routine is called by the ICMP module when it gets some sort of error
189 * condition. If err < 0 then the socket should be closed and the error
190 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
191 * After adjustment header points to the first 8 bytes of the tcp header. We
192 * need to find the appropriate port.
194 * The locking strategy used here is very "optimistic". When someone else
195 * accesses the socket the ICMP is just dropped and for some paths there is no
196 * check at all. A more general error queue to queue errors for later handling
197 * is probably better.
199 static void dccp_v4_err(struct sk_buff *skb, u32 info)
201 const struct iphdr *iph = (struct iphdr *)skb->data;
202 const u8 offset = iph->ihl << 2;
203 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
204 struct dccp_sock *dp;
205 struct inet_sock *inet;
206 const int type = icmp_hdr(skb)->type;
207 const int code = icmp_hdr(skb)->code;
211 struct net *net = dev_net(skb->dev);
213 if (skb->len < offset + sizeof(*dh) ||
214 skb->len < offset + __dccp_basic_hdr_len(dh)) {
215 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
219 sk = inet_lookup(net, &dccp_hashinfo,
220 iph->daddr, dh->dccph_dport,
221 iph->saddr, dh->dccph_sport, inet_iif(skb));
223 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
227 if (sk->sk_state == DCCP_TIME_WAIT) {
228 inet_twsk_put(inet_twsk(sk));
233 /* If too many ICMPs get dropped on busy
234 * servers this needs to be solved differently.
236 if (sock_owned_by_user(sk))
237 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
239 if (sk->sk_state == DCCP_CLOSED)
243 seq = dccp_hdr_seq(dh);
244 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
245 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
246 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
251 case ICMP_SOURCE_QUENCH:
252 /* Just silently ignore these. */
254 case ICMP_PARAMETERPROB:
257 case ICMP_DEST_UNREACH:
258 if (code > NR_ICMP_UNREACH)
261 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
262 if (!sock_owned_by_user(sk))
263 dccp_do_pmtu_discovery(sk, iph, info);
267 err = icmp_err_convert[code].errno;
269 case ICMP_TIME_EXCEEDED:
276 switch (sk->sk_state) {
277 struct request_sock *req , **prev;
279 if (sock_owned_by_user(sk))
281 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
282 iph->daddr, iph->saddr);
287 * ICMPs are not backlogged, hence we cannot get an established
292 if (seq != dccp_rsk(req)->dreq_iss) {
293 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
297 * Still in RESPOND, just remove it silently.
298 * There is no good way to pass the error to the newly
299 * created socket, and POSIX does not want network
300 * errors returned from accept().
302 inet_csk_reqsk_queue_drop(sk, req, prev);
305 case DCCP_REQUESTING:
307 if (!sock_owned_by_user(sk)) {
308 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
311 sk->sk_error_report(sk);
315 sk->sk_err_soft = err;
319 /* If we've already connected we will keep trying
320 * until we time out, or the user gives up.
322 * rfc1122 4.2.3.9 allows to consider as hard errors
323 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
324 * but it is obsoleted by pmtu discovery).
326 * Note, that in modern internet, where routing is unreliable
327 * and in each dark corner broken firewalls sit, sending random
328 * errors ordered by their masters even this two messages finally lose
329 * their original sense (even Linux sends invalid PORT_UNREACHs)
331 * Now we are in compliance with RFCs.
336 if (!sock_owned_by_user(sk) && inet->recverr) {
338 sk->sk_error_report(sk);
339 } else /* Only an error on timeout */
340 sk->sk_err_soft = err;
346 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
347 __be32 src, __be32 dst)
349 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
352 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
354 const struct inet_sock *inet = inet_sk(sk);
355 struct dccp_hdr *dh = dccp_hdr(skb);
357 dccp_csum_outgoing(skb);
358 dh->dccph_checksum = dccp_v4_csum_finish(skb,
363 EXPORT_SYMBOL_GPL(dccp_v4_send_check);
365 static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
367 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
369 dccp_hdr(skb)->dccph_dport,
370 dccp_hdr(skb)->dccph_sport);
374 * The three way handshake has completed - we got a valid ACK or DATAACK -
375 * now create the new socket.
377 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
379 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
380 struct request_sock *req,
381 struct dst_entry *dst)
383 struct inet_request_sock *ireq;
384 struct inet_sock *newinet;
387 if (sk_acceptq_is_full(sk))
390 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
393 newsk = dccp_create_openreq_child(sk, req, skb);
397 sk_setup_caps(newsk, dst);
399 newinet = inet_sk(newsk);
400 ireq = inet_rsk(req);
401 newinet->inet_daddr = ireq->rmt_addr;
402 newinet->inet_rcv_saddr = ireq->loc_addr;
403 newinet->inet_saddr = ireq->loc_addr;
404 newinet->opt = ireq->opt;
406 newinet->mc_index = inet_iif(skb);
407 newinet->mc_ttl = ip_hdr(skb)->ttl;
408 newinet->inet_id = jiffies;
410 dccp_sync_mss(newsk, dst_mtu(dst));
412 if (__inet_inherit_port(sk, newsk) < 0) {
416 __inet_hash_nolisten(newsk, NULL);
421 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
425 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
429 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
431 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
433 const struct dccp_hdr *dh = dccp_hdr(skb);
434 const struct iphdr *iph = ip_hdr(skb);
436 struct request_sock **prev;
437 /* Find possible connection requests. */
438 struct request_sock *req = inet_csk_search_req(sk, &prev,
440 iph->saddr, iph->daddr);
442 return dccp_check_req(sk, skb, req, prev);
444 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
445 iph->saddr, dh->dccph_sport,
446 iph->daddr, dh->dccph_dport,
449 if (nsk->sk_state != DCCP_TIME_WAIT) {
453 inet_twsk_put(inet_twsk(nsk));
460 static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
464 struct flowi fl = { .oif = skb_rtable(skb)->rt_iif,
465 .fl4_dst = ip_hdr(skb)->saddr,
466 .fl4_src = ip_hdr(skb)->daddr,
467 .fl4_tos = RT_CONN_FLAGS(sk),
468 .proto = sk->sk_protocol,
469 .fl_ip_sport = dccp_hdr(skb)->dccph_dport,
470 .fl_ip_dport = dccp_hdr(skb)->dccph_sport
473 security_skb_classify_flow(skb, &fl);
474 if (ip_route_output_flow(net, &rt, &fl, sk, 0)) {
475 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
482 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
483 struct request_values *rv_unused)
487 struct dst_entry *dst;
489 dst = inet_csk_route_req(sk, req);
493 skb = dccp_make_response(sk, dst, req);
495 const struct inet_request_sock *ireq = inet_rsk(req);
496 struct dccp_hdr *dh = dccp_hdr(skb);
498 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
500 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
503 err = net_xmit_eval(err);
511 static void dccp_v4_ctl_send_reset(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));
540 bh_lock_sock(ctl_sk);
541 err = ip_build_and_send_pkt(skb, ctl_sk,
542 rxiph->daddr, rxiph->saddr, NULL);
543 bh_unlock_sock(ctl_sk);
545 if (net_xmit_eval(err) == 0) {
546 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
547 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
553 static void dccp_v4_reqsk_destructor(struct request_sock *req)
555 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
556 kfree(inet_rsk(req)->opt);
559 static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
561 .obj_size = sizeof(struct dccp_request_sock),
562 .rtx_syn_ack = dccp_v4_send_response,
563 .send_ack = dccp_reqsk_send_ack,
564 .destructor = dccp_v4_reqsk_destructor,
565 .send_reset = dccp_v4_ctl_send_reset,
568 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
570 struct inet_request_sock *ireq;
571 struct request_sock *req;
572 struct dccp_request_sock *dreq;
573 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
574 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
576 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
577 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
578 return 0; /* discard, don't send a reset here */
580 if (dccp_bad_service_code(sk, service)) {
581 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
585 * TW buckets are converted to open requests without
586 * limitations, they conserve resources and peer is
587 * evidently real one.
589 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
590 if (inet_csk_reqsk_queue_is_full(sk))
594 * Accept backlog is full. If we have already queued enough
595 * of warm entries in syn queue, drop request. It is better than
596 * clogging syn queue with openreqs with exponentially increasing
599 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
602 req = inet_reqsk_alloc(&dccp_request_sock_ops);
606 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
609 dreq = dccp_rsk(req);
610 if (dccp_parse_options(sk, dreq, skb))
613 if (security_inet_conn_request(sk, skb, req))
616 ireq = inet_rsk(req);
617 ireq->loc_addr = ip_hdr(skb)->daddr;
618 ireq->rmt_addr = ip_hdr(skb)->saddr;
621 * Step 3: Process LISTEN state
623 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
625 * In fact we defer setting S.GSR, S.SWL, S.SWH to
626 * dccp_create_openreq_child.
628 dreq->dreq_isr = dcb->dccpd_seq;
629 dreq->dreq_iss = dccp_v4_init_sequence(skb);
630 dreq->dreq_service = service;
632 if (dccp_v4_send_response(sk, req, NULL))
635 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
641 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
645 EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
647 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
649 struct dccp_hdr *dh = dccp_hdr(skb);
651 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
652 if (dccp_rcv_established(sk, skb, dh, skb->len))
658 * Step 3: Process LISTEN state
659 * If P.type == Request or P contains a valid Init Cookie option,
660 * (* Must scan the packet's options to check for Init
661 * Cookies. Only Init Cookies are processed here,
662 * however; other options are processed in Step 8. This
663 * scan need only be performed if the endpoint uses Init
665 * (* Generate a new socket and switch to that socket *)
666 * Set S := new socket for this port pair
668 * Choose S.ISS (initial seqno) or set from Init Cookies
669 * Initialize S.GAR := S.ISS
670 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
671 * Continue with S.state == RESPOND
672 * (* A Response packet will be generated in Step 11 *)
674 * Generate Reset(No Connection) unless P.type == Reset
675 * Drop packet and return
677 * NOTE: the check for the packet types is done in
678 * dccp_rcv_state_process
680 if (sk->sk_state == DCCP_LISTEN) {
681 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
687 if (dccp_child_process(sk, nsk, skb))
693 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
698 dccp_v4_ctl_send_reset(sk, skb);
704 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
707 * dccp_invalid_packet - check for malformed packets
708 * Implements RFC 4340, 8.5: Step 1: Check header basics
709 * Packets that fail these checks are ignored and do not receive Resets.
711 int dccp_invalid_packet(struct sk_buff *skb)
713 const struct dccp_hdr *dh;
716 if (skb->pkt_type != PACKET_HOST)
719 /* If the packet is shorter than 12 bytes, drop packet and return */
720 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
721 DCCP_WARN("pskb_may_pull failed\n");
727 /* If P.type is not understood, drop packet and return */
728 if (dh->dccph_type >= DCCP_PKT_INVALID) {
729 DCCP_WARN("invalid packet type\n");
734 * If P.Data Offset is too small for packet type, drop packet and return
736 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
737 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
741 * If P.Data Offset is too too large for packet, drop packet and return
743 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
744 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
749 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
750 * has short sequence numbers), drop packet and return
752 if ((dh->dccph_type < DCCP_PKT_DATA ||
753 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
754 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
755 dccp_packet_name(dh->dccph_type));
760 * If P.CsCov is too large for the packet size, drop packet and return.
761 * This must come _before_ checksumming (not as RFC 4340 suggests).
763 cscov = dccp_csum_coverage(skb);
764 if (cscov > skb->len) {
765 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
766 dh->dccph_cscov, skb->len);
770 /* If header checksum is incorrect, drop packet and return.
771 * (This step is completed in the AF-dependent functions.) */
772 skb->csum = skb_checksum(skb, 0, cscov, 0);
777 EXPORT_SYMBOL_GPL(dccp_invalid_packet);
779 /* this is called when real data arrives */
780 static int dccp_v4_rcv(struct sk_buff *skb)
782 const struct dccp_hdr *dh;
783 const struct iphdr *iph;
787 /* Step 1: Check header basics */
789 if (dccp_invalid_packet(skb))
793 /* Step 1: If header checksum is incorrect, drop packet and return */
794 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
795 DCCP_WARN("dropped packet with invalid checksum\n");
801 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
802 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
804 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
805 dccp_packet_name(dh->dccph_type),
806 &iph->saddr, ntohs(dh->dccph_sport),
807 &iph->daddr, ntohs(dh->dccph_dport),
808 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
810 if (dccp_packet_without_ack(skb)) {
811 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
812 dccp_pr_debug_cat("\n");
814 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
815 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
816 DCCP_SKB_CB(skb)->dccpd_ack_seq);
820 * Look up flow ID in table and get corresponding socket */
821 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
822 dh->dccph_sport, dh->dccph_dport);
828 dccp_pr_debug("failed to look up flow ID in table and "
829 "get corresponding socket\n");
835 * ... or S.state == TIMEWAIT,
836 * Generate Reset(No Connection) unless P.type == Reset
837 * Drop packet and return
839 if (sk->sk_state == DCCP_TIME_WAIT) {
840 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
841 inet_twsk_put(inet_twsk(sk));
846 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
847 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
848 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
850 min_cov = dccp_sk(sk)->dccps_pcrlen;
851 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
852 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
853 dh->dccph_cscov, min_cov);
854 /* FIXME: "Such packets SHOULD be reported using Data Dropped
855 * options (Section 11.7) with Drop Code 0, Protocol
857 goto discard_and_relse;
860 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
861 goto discard_and_relse;
864 return sk_receive_skb(sk, skb, 1);
867 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
872 * Generate Reset(No Connection) unless P.type == Reset
873 * Drop packet and return
875 if (dh->dccph_type != DCCP_PKT_RESET) {
876 DCCP_SKB_CB(skb)->dccpd_reset_code =
877 DCCP_RESET_CODE_NO_CONNECTION;
878 dccp_v4_ctl_send_reset(sk, skb);
890 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
891 .queue_xmit = ip_queue_xmit,
892 .send_check = dccp_v4_send_check,
893 .rebuild_header = inet_sk_rebuild_header,
894 .conn_request = dccp_v4_conn_request,
895 .syn_recv_sock = dccp_v4_request_recv_sock,
896 .net_header_len = sizeof(struct iphdr),
897 .setsockopt = ip_setsockopt,
898 .getsockopt = ip_getsockopt,
899 .addr2sockaddr = inet_csk_addr2sockaddr,
900 .sockaddr_len = sizeof(struct sockaddr_in),
901 .bind_conflict = inet_csk_bind_conflict,
903 .compat_setsockopt = compat_ip_setsockopt,
904 .compat_getsockopt = compat_ip_getsockopt,
908 static int dccp_v4_init_sock(struct sock *sk)
910 static __u8 dccp_v4_ctl_sock_initialized;
911 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
914 if (unlikely(!dccp_v4_ctl_sock_initialized))
915 dccp_v4_ctl_sock_initialized = 1;
916 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
922 static struct timewait_sock_ops dccp_timewait_sock_ops = {
923 .twsk_obj_size = sizeof(struct inet_timewait_sock),
926 static struct proto dccp_v4_prot = {
928 .owner = THIS_MODULE,
930 .connect = dccp_v4_connect,
931 .disconnect = dccp_disconnect,
933 .init = dccp_v4_init_sock,
934 .setsockopt = dccp_setsockopt,
935 .getsockopt = dccp_getsockopt,
936 .sendmsg = dccp_sendmsg,
937 .recvmsg = dccp_recvmsg,
938 .backlog_rcv = dccp_v4_do_rcv,
940 .unhash = inet_unhash,
941 .accept = inet_csk_accept,
942 .get_port = inet_csk_get_port,
943 .shutdown = dccp_shutdown,
944 .destroy = dccp_destroy_sock,
945 .orphan_count = &dccp_orphan_count,
946 .max_header = MAX_DCCP_HEADER,
947 .obj_size = sizeof(struct dccp_sock),
948 .slab_flags = SLAB_DESTROY_BY_RCU,
949 .rsk_prot = &dccp_request_sock_ops,
950 .twsk_prot = &dccp_timewait_sock_ops,
951 .h.hashinfo = &dccp_hashinfo,
953 .compat_setsockopt = compat_dccp_setsockopt,
954 .compat_getsockopt = compat_dccp_getsockopt,
958 static const struct net_protocol dccp_v4_protocol = {
959 .handler = dccp_v4_rcv,
960 .err_handler = dccp_v4_err,
965 static const struct proto_ops inet_dccp_ops = {
967 .owner = THIS_MODULE,
968 .release = inet_release,
970 .connect = inet_stream_connect,
971 .socketpair = sock_no_socketpair,
972 .accept = inet_accept,
973 .getname = inet_getname,
974 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
977 /* FIXME: work on inet_listen to rename it to sock_common_listen */
978 .listen = inet_dccp_listen,
979 .shutdown = inet_shutdown,
980 .setsockopt = sock_common_setsockopt,
981 .getsockopt = sock_common_getsockopt,
982 .sendmsg = inet_sendmsg,
983 .recvmsg = sock_common_recvmsg,
984 .mmap = sock_no_mmap,
985 .sendpage = sock_no_sendpage,
987 .compat_setsockopt = compat_sock_common_setsockopt,
988 .compat_getsockopt = compat_sock_common_getsockopt,
992 static struct inet_protosw dccp_v4_protosw = {
994 .protocol = IPPROTO_DCCP,
995 .prot = &dccp_v4_prot,
996 .ops = &inet_dccp_ops,
998 .flags = INET_PROTOSW_ICSK,
1001 static int __net_init dccp_v4_init_net(struct net *net)
1003 if (dccp_hashinfo.bhash == NULL)
1004 return -ESOCKTNOSUPPORT;
1006 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1007 SOCK_DCCP, IPPROTO_DCCP, net);
1010 static void __net_exit dccp_v4_exit_net(struct net *net)
1012 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
1015 static struct pernet_operations dccp_v4_ops = {
1016 .init = dccp_v4_init_net,
1017 .exit = dccp_v4_exit_net,
1020 static int __init dccp_v4_init(void)
1022 int err = proto_register(&dccp_v4_prot, 1);
1027 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1029 goto out_proto_unregister;
1031 inet_register_protosw(&dccp_v4_protosw);
1033 err = register_pernet_subsys(&dccp_v4_ops);
1035 goto out_destroy_ctl_sock;
1038 out_destroy_ctl_sock:
1039 inet_unregister_protosw(&dccp_v4_protosw);
1040 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1041 out_proto_unregister:
1042 proto_unregister(&dccp_v4_prot);
1046 static void __exit dccp_v4_exit(void)
1048 unregister_pernet_subsys(&dccp_v4_ops);
1049 inet_unregister_protosw(&dccp_v4_protosw);
1050 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1051 proto_unregister(&dccp_v4_prot);
1054 module_init(dccp_v4_init);
1055 module_exit(dccp_v4_exit);
1058 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1059 * values directly, Also cover the case where the protocol is not specified,
1060 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1062 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1063 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
1064 MODULE_LICENSE("GPL");
1065 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1066 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");