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/config.h>
14 #include <linux/dccp.h>
15 #include <linux/icmp.h>
16 #include <linux/module.h>
17 #include <linux/skbuff.h>
18 #include <linux/random.h>
21 #include <net/inet_hashtables.h>
23 #include <net/tcp_states.h>
30 struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
31 .lhash_lock = RW_LOCK_UNLOCKED,
32 .lhash_users = ATOMIC_INIT(0),
33 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
34 .portalloc_lock = SPIN_LOCK_UNLOCKED,
35 .port_rover = 1024 - 1,
38 EXPORT_SYMBOL_GPL(dccp_hashinfo);
40 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
42 return inet_csk_get_port(&dccp_hashinfo, sk, snum);
45 static void dccp_v4_hash(struct sock *sk)
47 inet_hash(&dccp_hashinfo, sk);
50 static void dccp_v4_unhash(struct sock *sk)
52 inet_unhash(&dccp_hashinfo, sk);
55 /* called with local bh disabled */
56 static int __dccp_v4_check_established(struct sock *sk, const __u16 lport,
57 struct inet_timewait_sock **twp)
59 struct inet_sock *inet = inet_sk(sk);
60 const u32 daddr = inet->rcv_saddr;
61 const u32 saddr = inet->daddr;
62 const int dif = sk->sk_bound_dev_if;
63 INET_ADDR_COOKIE(acookie, saddr, daddr)
64 const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
65 unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport);
66 struct inet_ehash_bucket *head = inet_ehash_bucket(&dccp_hashinfo, hash);
67 const struct sock *sk2;
68 const struct hlist_node *node;
69 struct inet_timewait_sock *tw;
71 prefetch(head->chain.first);
72 write_lock(&head->lock);
74 /* Check TIME-WAIT sockets first. */
75 sk_for_each(sk2, node, &(head + dccp_hashinfo.ehash_size)->chain) {
78 if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif))
83 /* And established part... */
84 sk_for_each(sk2, node, &head->chain) {
85 if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif))
89 /* Must record num and sport now. Otherwise we will see
90 * in hash table socket with a funny identity. */
92 inet->sport = htons(lport);
94 BUG_TRAP(sk_unhashed(sk));
95 __sk_add_node(sk, &head->chain);
96 sock_prot_inc_use(sk->sk_prot);
97 write_unlock(&head->lock);
101 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
102 } else if (tw != NULL) {
103 /* Silly. Should hash-dance instead... */
104 inet_twsk_deschedule(tw, &dccp_death_row);
105 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
113 write_unlock(&head->lock);
114 return -EADDRNOTAVAIL;
118 * Bind a port for a connect operation and hash it.
120 static int dccp_v4_hash_connect(struct sock *sk)
122 const unsigned short snum = inet_sk(sk)->num;
123 struct inet_bind_hashbucket *head;
124 struct inet_bind_bucket *tb;
129 int low = sysctl_local_port_range[0];
130 int high = sysctl_local_port_range[1];
131 int remaining = (high - low) + 1;
132 struct hlist_node *node;
133 struct inet_timewait_sock *tw = NULL;
137 /* TODO. Actually it is not so bad idea to remove
138 * dccp_hashinfo.portalloc_lock before next submission to
140 * As soon as we touch this place at all it is time to think.
142 * Now it protects single _advisory_ variable
143 * dccp_hashinfo.port_rover, hence it is mostly useless.
144 * Code will work nicely if we just delete it, but
145 * I am afraid in contented case it will work not better or
146 * even worse: another cpu just will hit the same bucket
148 * So some cpu salt could remove both contention and
149 * memory pingpong. Any ideas how to do this in a nice way?
151 spin_lock(&dccp_hashinfo.portalloc_lock);
152 rover = dccp_hashinfo.port_rover;
156 if ((rover < low) || (rover > high))
158 head = &dccp_hashinfo.bhash[inet_bhashfn(rover,
159 dccp_hashinfo.bhash_size)];
160 spin_lock(&head->lock);
162 /* Does not bother with rcv_saddr checks,
163 * because the established check is already
166 inet_bind_bucket_for_each(tb, node, &head->chain) {
167 if (tb->port == rover) {
168 BUG_TRAP(!hlist_empty(&tb->owners));
169 if (tb->fastreuse >= 0)
171 if (!__dccp_v4_check_established(sk,
179 tb = inet_bind_bucket_create(dccp_hashinfo.bind_bucket_cachep,
182 spin_unlock(&head->lock);
189 spin_unlock(&head->lock);
190 } while (--remaining > 0);
191 dccp_hashinfo.port_rover = rover;
192 spin_unlock(&dccp_hashinfo.portalloc_lock);
196 return -EADDRNOTAVAIL;
199 /* All locks still held and bhs disabled */
200 dccp_hashinfo.port_rover = rover;
201 spin_unlock(&dccp_hashinfo.portalloc_lock);
203 inet_bind_hash(sk, tb, rover);
204 if (sk_unhashed(sk)) {
205 inet_sk(sk)->sport = htons(rover);
206 __inet_hash(&dccp_hashinfo, sk, 0);
208 spin_unlock(&head->lock);
211 inet_twsk_deschedule(tw, &dccp_death_row);
219 head = &dccp_hashinfo.bhash[inet_bhashfn(snum,
220 dccp_hashinfo.bhash_size)];
221 tb = inet_csk(sk)->icsk_bind_hash;
222 spin_lock_bh(&head->lock);
223 if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
224 __inet_hash(&dccp_hashinfo, sk, 0);
225 spin_unlock_bh(&head->lock);
228 spin_unlock(&head->lock);
229 /* No definite answer... Walk to established hash table */
230 ret = __dccp_v4_check_established(sk, snum, NULL);
237 static int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
240 struct inet_sock *inet = inet_sk(sk);
241 struct dccp_sock *dp = dccp_sk(sk);
242 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
248 dp->dccps_role = DCCP_ROLE_CLIENT;
250 if (dccp_service_not_initialized(sk))
253 if (addr_len < sizeof(struct sockaddr_in))
256 if (usin->sin_family != AF_INET)
257 return -EAFNOSUPPORT;
259 nexthop = daddr = usin->sin_addr.s_addr;
260 if (inet->opt != NULL && inet->opt->srr) {
263 nexthop = inet->opt->faddr;
266 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
267 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
269 inet->sport, usin->sin_port, sk);
273 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
278 if (inet->opt == NULL || !inet->opt->srr)
281 if (inet->saddr == 0)
282 inet->saddr = rt->rt_src;
283 inet->rcv_saddr = inet->saddr;
285 inet->dport = usin->sin_port;
288 dp->dccps_ext_header_len = 0;
289 if (inet->opt != NULL)
290 dp->dccps_ext_header_len = inet->opt->optlen;
292 * Socket identity is still unknown (sport may be zero).
293 * However we set state to DCCP_REQUESTING and not releasing socket
294 * lock select source port, enter ourselves into the hash tables and
295 * complete initialization after this.
297 dccp_set_state(sk, DCCP_REQUESTING);
298 err = dccp_v4_hash_connect(sk);
302 err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
306 /* OK, now commit destination to socket. */
307 sk_setup_caps(sk, &rt->u.dst);
310 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
314 dccp_update_gss(sk, dp->dccps_iss);
317 * SWL and AWL are initially adjusted so that they are not less than
318 * the initial Sequence Numbers received and sent, respectively:
319 * SWL := max(GSR + 1 - floor(W/4), ISR),
320 * AWL := max(GSS - W' + 1, ISS).
321 * These adjustments MUST be applied only at the beginning of the
324 dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
326 inet->id = dp->dccps_iss ^ jiffies;
328 err = dccp_connect(sk);
336 * This unhashes the socket and releases the local port, if necessary.
338 dccp_set_state(sk, DCCP_CLOSED);
340 sk->sk_route_caps = 0;
346 * This routine does path mtu discovery as defined in RFC1191.
348 static inline void dccp_do_pmtu_discovery(struct sock *sk,
349 const struct iphdr *iph,
352 struct dst_entry *dst;
353 const struct inet_sock *inet = inet_sk(sk);
354 const struct dccp_sock *dp = dccp_sk(sk);
356 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
357 * send out by Linux are always < 576bytes so they should go through
360 if (sk->sk_state == DCCP_LISTEN)
363 /* We don't check in the destentry if pmtu discovery is forbidden
364 * on this route. We just assume that no packet_to_big packets
365 * are send back when pmtu discovery is not active.
366 * There is a small race when the user changes this flag in the
367 * route, but I think that's acceptable.
369 if ((dst = __sk_dst_check(sk, 0)) == NULL)
372 dst->ops->update_pmtu(dst, mtu);
374 /* Something is about to be wrong... Remember soft error
375 * for the case, if this connection will not able to recover.
377 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
378 sk->sk_err_soft = EMSGSIZE;
382 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
383 dp->dccps_pmtu_cookie > mtu) {
384 dccp_sync_mss(sk, mtu);
387 * From: draft-ietf-dccp-spec-11.txt
389 * DCCP-Sync packets are the best choice for upward
390 * probing, since DCCP-Sync probes do not risk application
393 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
394 } /* else let the usual retransmit timer handle it */
397 static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
400 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
401 const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
402 sizeof(struct dccp_hdr_ext) +
403 sizeof(struct dccp_hdr_ack_bits);
406 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
409 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
413 /* Reserve space for headers. */
414 skb_reserve(skb, MAX_DCCP_HEADER);
416 skb->dst = dst_clone(rxskb->dst);
418 skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
420 memset(dh, 0, dccp_hdr_ack_len);
422 /* Build DCCP header and checksum it. */
423 dh->dccph_type = DCCP_PKT_ACK;
424 dh->dccph_sport = rxdh->dccph_dport;
425 dh->dccph_dport = rxdh->dccph_sport;
426 dh->dccph_doff = dccp_hdr_ack_len / 4;
429 dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
430 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
431 DCCP_SKB_CB(rxskb)->dccpd_seq);
433 bh_lock_sock(dccp_ctl_socket->sk);
434 err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
435 rxskb->nh.iph->daddr,
436 rxskb->nh.iph->saddr, NULL);
437 bh_unlock_sock(dccp_ctl_socket->sk);
439 if (err == NET_XMIT_CN || err == 0) {
440 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
441 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
445 static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
446 struct request_sock *req)
448 dccp_v4_ctl_send_ack(skb);
451 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
452 struct dst_entry *dst)
457 /* First, grab a route. */
459 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
462 skb = dccp_make_response(sk, dst, req);
464 const struct inet_request_sock *ireq = inet_rsk(req);
466 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
467 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
470 if (err == NET_XMIT_CN)
480 * This routine is called by the ICMP module when it gets some sort of error
481 * condition. If err < 0 then the socket should be closed and the error
482 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
483 * After adjustment header points to the first 8 bytes of the tcp header. We
484 * need to find the appropriate port.
486 * The locking strategy used here is very "optimistic". When someone else
487 * accesses the socket the ICMP is just dropped and for some paths there is no
488 * check at all. A more general error queue to queue errors for later handling
489 * is probably better.
491 void dccp_v4_err(struct sk_buff *skb, u32 info)
493 const struct iphdr *iph = (struct iphdr *)skb->data;
494 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
496 struct dccp_sock *dp;
497 struct inet_sock *inet;
498 const int type = skb->h.icmph->type;
499 const int code = skb->h.icmph->code;
504 if (skb->len < (iph->ihl << 2) + 8) {
505 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
509 sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
510 iph->saddr, dh->dccph_sport, inet_iif(skb));
512 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
516 if (sk->sk_state == DCCP_TIME_WAIT) {
517 inet_twsk_put((struct inet_timewait_sock *)sk);
522 /* If too many ICMPs get dropped on busy
523 * servers this needs to be solved differently.
525 if (sock_owned_by_user(sk))
526 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
528 if (sk->sk_state == DCCP_CLOSED)
532 seq = dccp_hdr_seq(skb);
533 if (sk->sk_state != DCCP_LISTEN &&
534 !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
535 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
540 case ICMP_SOURCE_QUENCH:
541 /* Just silently ignore these. */
543 case ICMP_PARAMETERPROB:
546 case ICMP_DEST_UNREACH:
547 if (code > NR_ICMP_UNREACH)
550 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
551 if (!sock_owned_by_user(sk))
552 dccp_do_pmtu_discovery(sk, iph, info);
556 err = icmp_err_convert[code].errno;
558 case ICMP_TIME_EXCEEDED:
565 switch (sk->sk_state) {
566 struct request_sock *req , **prev;
568 if (sock_owned_by_user(sk))
570 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
571 iph->daddr, iph->saddr);
576 * ICMPs are not backlogged, hence we cannot get an established
581 if (seq != dccp_rsk(req)->dreq_iss) {
582 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
586 * Still in RESPOND, just remove it silently.
587 * There is no good way to pass the error to the newly
588 * created socket, and POSIX does not want network
589 * errors returned from accept().
591 inet_csk_reqsk_queue_drop(sk, req, prev);
594 case DCCP_REQUESTING:
596 if (!sock_owned_by_user(sk)) {
597 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
600 sk->sk_error_report(sk);
604 sk->sk_err_soft = err;
608 /* If we've already connected we will keep trying
609 * until we time out, or the user gives up.
611 * rfc1122 4.2.3.9 allows to consider as hard errors
612 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
613 * but it is obsoleted by pmtu discovery).
615 * Note, that in modern internet, where routing is unreliable
616 * and in each dark corner broken firewalls sit, sending random
617 * errors ordered by their masters even this two messages finally lose
618 * their original sense (even Linux sends invalid PORT_UNREACHs)
620 * Now we are in compliance with RFCs.
625 if (!sock_owned_by_user(sk) && inet->recverr) {
627 sk->sk_error_report(sk);
628 } else /* Only an error on timeout */
629 sk->sk_err_soft = err;
635 int dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code)
639 * FIXME: what if rebuild_header fails?
640 * Should we be doing a rebuild_header here?
642 int err = inet_sk_rebuild_header(sk);
647 skb = dccp_make_reset(sk, sk->sk_dst_cache, code);
649 const struct inet_sock *inet = inet_sk(sk);
651 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
652 err = ip_build_and_send_pkt(skb, sk,
653 inet->saddr, inet->daddr, NULL);
654 if (err == NET_XMIT_CN)
661 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
662 const struct sk_buff *skb)
664 return secure_dccp_sequence_number(skb->nh.iph->daddr,
666 dccp_hdr(skb)->dccph_dport,
667 dccp_hdr(skb)->dccph_sport);
670 static inline int dccp_bad_service_code(const struct sock *sk,
673 const struct dccp_sock *dp = dccp_sk(sk);
675 if (dp->dccps_service == service)
677 return !dccp_list_has_service(dp->dccps_service_list, service);
680 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
682 struct inet_request_sock *ireq;
684 struct request_sock *req;
685 struct dccp_request_sock *dreq;
686 const __u32 saddr = skb->nh.iph->saddr;
687 const __u32 daddr = skb->nh.iph->daddr;
688 const __u32 service = dccp_hdr_request(skb)->dccph_req_service;
689 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
690 __u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
691 struct dst_entry *dst = NULL;
693 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
694 if (((struct rtable *)skb->dst)->rt_flags &
695 (RTCF_BROADCAST | RTCF_MULTICAST)) {
696 reset_code = DCCP_RESET_CODE_NO_CONNECTION;
700 if (dccp_bad_service_code(sk, service)) {
701 reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
705 * TW buckets are converted to open requests without
706 * limitations, they conserve resources and peer is
707 * evidently real one.
709 if (inet_csk_reqsk_queue_is_full(sk))
713 * Accept backlog is full. If we have already queued enough
714 * of warm entries in syn queue, drop request. It is better than
715 * clogging syn queue with openreqs with exponentially increasing
718 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
721 req = reqsk_alloc(sk->sk_prot->rsk_prot);
725 /* FIXME: process options */
727 dccp_openreq_init(req, &dp, skb);
729 ireq = inet_rsk(req);
730 ireq->loc_addr = daddr;
731 ireq->rmt_addr = saddr;
732 /* FIXME: Merge Aristeu's option parsing code when ready */
733 req->rcv_wnd = 100; /* Fake, option parsing will get the
738 * Step 3: Process LISTEN state
740 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
742 * In fact we defer setting S.GSR, S.SWL, S.SWH to
743 * dccp_create_openreq_child.
745 dreq = dccp_rsk(req);
746 dreq->dreq_isr = dcb->dccpd_seq;
747 dreq->dreq_iss = dccp_v4_init_sequence(sk, skb);
748 dreq->dreq_service = service;
750 if (dccp_v4_send_response(sk, req, dst))
753 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
758 * FIXME: should be reqsk_free after implementing req->rsk_ops
762 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
763 dcb->dccpd_reset_code = reset_code;
768 * The three way handshake has completed - we got a valid ACK or DATAACK -
769 * now create the new socket.
771 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
773 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
774 struct request_sock *req,
775 struct dst_entry *dst)
777 struct inet_request_sock *ireq;
778 struct inet_sock *newinet;
779 struct dccp_sock *newdp;
782 if (sk_acceptq_is_full(sk))
785 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
788 newsk = dccp_create_openreq_child(sk, req, skb);
792 sk_setup_caps(newsk, dst);
794 newdp = dccp_sk(newsk);
795 newinet = inet_sk(newsk);
796 ireq = inet_rsk(req);
797 newinet->daddr = ireq->rmt_addr;
798 newinet->rcv_saddr = ireq->loc_addr;
799 newinet->saddr = ireq->loc_addr;
800 newinet->opt = ireq->opt;
802 newinet->mc_index = inet_iif(skb);
803 newinet->mc_ttl = skb->nh.iph->ttl;
804 newinet->id = jiffies;
806 dccp_sync_mss(newsk, dst_mtu(dst));
808 __inet_hash(&dccp_hashinfo, newsk, 0);
809 __inet_inherit_port(&dccp_hashinfo, sk, newsk);
814 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
816 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
821 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
823 const struct dccp_hdr *dh = dccp_hdr(skb);
824 const struct iphdr *iph = skb->nh.iph;
826 struct request_sock **prev;
827 /* Find possible connection requests. */
828 struct request_sock *req = inet_csk_search_req(sk, &prev,
830 iph->saddr, iph->daddr);
832 return dccp_check_req(sk, skb, req, prev);
834 nsk = __inet_lookup_established(&dccp_hashinfo,
835 iph->saddr, dh->dccph_sport,
836 iph->daddr, ntohs(dh->dccph_dport),
839 if (nsk->sk_state != DCCP_TIME_WAIT) {
843 inet_twsk_put((struct inet_timewait_sock *)nsk);
850 int dccp_v4_checksum(const struct sk_buff *skb, const u32 saddr,
853 const struct dccp_hdr* dh = dccp_hdr(skb);
857 if (dh->dccph_cscov == 0)
858 checksum_len = skb->len;
860 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
861 checksum_len = checksum_len < skb->len ? checksum_len :
865 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
866 return csum_tcpudp_magic(saddr, daddr, checksum_len,
870 static int dccp_v4_verify_checksum(struct sk_buff *skb,
871 const u32 saddr, const u32 daddr)
873 struct dccp_hdr *dh = dccp_hdr(skb);
877 if (dh->dccph_cscov == 0)
878 checksum_len = skb->len;
880 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
881 checksum_len = checksum_len < skb->len ? checksum_len :
884 tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
885 return csum_tcpudp_magic(saddr, daddr, checksum_len,
886 IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
889 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
893 struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
895 { .daddr = skb->nh.iph->saddr,
896 .saddr = skb->nh.iph->daddr,
897 .tos = RT_CONN_FLAGS(sk) } },
898 .proto = sk->sk_protocol,
900 { .sport = dccp_hdr(skb)->dccph_dport,
901 .dport = dccp_hdr(skb)->dccph_sport }
905 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
906 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
913 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
916 struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
917 const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
918 sizeof(struct dccp_hdr_ext) +
919 sizeof(struct dccp_hdr_reset);
921 struct dst_entry *dst;
924 /* Never send a reset in response to a reset. */
925 if (rxdh->dccph_type == DCCP_PKT_RESET)
928 if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
931 dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
935 skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
939 /* Reserve space for headers. */
940 skb_reserve(skb, MAX_DCCP_HEADER);
941 skb->dst = dst_clone(dst);
943 skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
945 memset(dh, 0, dccp_hdr_reset_len);
947 /* Build DCCP header and checksum it. */
948 dh->dccph_type = DCCP_PKT_RESET;
949 dh->dccph_sport = rxdh->dccph_dport;
950 dh->dccph_dport = rxdh->dccph_sport;
951 dh->dccph_doff = dccp_hdr_reset_len / 4;
953 dccp_hdr_reset(skb)->dccph_reset_code =
954 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
956 /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
958 if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
959 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
961 dccp_hdr_set_seq(dh, seqno);
962 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
963 DCCP_SKB_CB(rxskb)->dccpd_seq);
965 dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
966 rxskb->nh.iph->daddr);
968 bh_lock_sock(dccp_ctl_socket->sk);
969 err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
970 rxskb->nh.iph->daddr,
971 rxskb->nh.iph->saddr, NULL);
972 bh_unlock_sock(dccp_ctl_socket->sk);
974 if (err == NET_XMIT_CN || err == 0) {
975 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
976 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
982 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
984 struct dccp_hdr *dh = dccp_hdr(skb);
986 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
987 if (dccp_rcv_established(sk, skb, dh, skb->len))
993 * Step 3: Process LISTEN state
994 * If S.state == LISTEN,
995 * If P.type == Request or P contains a valid Init Cookie
997 * * Must scan the packet's options to check for an Init
998 * Cookie. Only the Init Cookie is processed here,
999 * however; other options are processed in Step 8. This
1000 * scan need only be performed if the endpoint uses Init
1002 * * Generate a new socket and switch to that socket *
1003 * Set S := new socket for this port pair
1005 * Choose S.ISS (initial seqno) or set from Init Cookie
1006 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
1007 * Continue with S.state == RESPOND
1008 * * A Response packet will be generated in Step 11 *
1010 * Generate Reset(No Connection) unless P.type == Reset
1011 * Drop packet and return
1013 * NOTE: the check for the packet types is done in
1014 * dccp_rcv_state_process
1016 if (sk->sk_state == DCCP_LISTEN) {
1017 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
1023 if (dccp_child_process(sk, nsk, skb))
1029 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
1034 dccp_v4_ctl_send_reset(skb);
1040 static inline int dccp_invalid_packet(struct sk_buff *skb)
1042 const struct dccp_hdr *dh;
1044 if (skb->pkt_type != PACKET_HOST)
1047 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
1048 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
1054 /* If the packet type is not understood, drop packet and return */
1055 if (dh->dccph_type >= DCCP_PKT_INVALID) {
1056 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
1061 * If P.Data Offset is too small for packet type, or too large for
1062 * packet, drop packet and return
1064 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
1065 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1071 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
1072 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1081 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
1082 * has short sequence numbers), drop packet and return
1084 if (dh->dccph_x == 0 &&
1085 dh->dccph_type != DCCP_PKT_DATA &&
1086 dh->dccph_type != DCCP_PKT_ACK &&
1087 dh->dccph_type != DCCP_PKT_DATAACK) {
1088 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
1089 "nor DataAck and P.X == 0\n",
1090 dccp_packet_name(dh->dccph_type));
1094 /* If the header checksum is incorrect, drop packet and return */
1095 if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
1096 skb->nh.iph->daddr) < 0) {
1097 LIMIT_NETDEBUG(KERN_WARNING "DCCP: header checksum is "
1105 /* this is called when real data arrives */
1106 int dccp_v4_rcv(struct sk_buff *skb)
1108 const struct dccp_hdr *dh;
1112 /* Step 1: Check header basics: */
1114 if (dccp_invalid_packet(skb))
1119 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
1120 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
1122 dccp_pr_debug("%8.8s "
1123 "src=%u.%u.%u.%u@%-5d "
1124 "dst=%u.%u.%u.%u@%-5d seq=%llu",
1125 dccp_packet_name(dh->dccph_type),
1126 NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
1127 NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
1128 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
1130 if (dccp_packet_without_ack(skb)) {
1131 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
1132 dccp_pr_debug_cat("\n");
1134 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
1135 dccp_pr_debug_cat(", ack=%llu\n",
1136 (unsigned long long)
1137 DCCP_SKB_CB(skb)->dccpd_ack_seq);
1141 * Look up flow ID in table and get corresponding socket */
1142 sk = __inet_lookup(&dccp_hashinfo,
1143 skb->nh.iph->saddr, dh->dccph_sport,
1144 skb->nh.iph->daddr, ntohs(dh->dccph_dport),
1150 * Generate Reset(No Connection) unless P.type == Reset
1151 * Drop packet and return
1154 dccp_pr_debug("failed to look up flow ID in table and "
1155 "get corresponding socket\n");
1156 goto no_dccp_socket;
1161 * ... or S.state == TIMEWAIT,
1162 * Generate Reset(No Connection) unless P.type == Reset
1163 * Drop packet and return
1166 if (sk->sk_state == DCCP_TIME_WAIT) {
1167 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
1172 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
1173 dccp_pr_debug("xfrm4_policy_check failed\n");
1174 goto discard_and_relse;
1177 if (sk_filter(sk, skb, 0)) {
1178 dccp_pr_debug("sk_filter failed\n");
1179 goto discard_and_relse;
1186 if (!sock_owned_by_user(sk))
1187 rc = dccp_v4_do_rcv(sk, skb);
1189 sk_add_backlog(sk, skb);
1196 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1200 * Generate Reset(No Connection) unless P.type == Reset
1201 * Drop packet and return
1203 if (dh->dccph_type != DCCP_PKT_RESET) {
1204 DCCP_SKB_CB(skb)->dccpd_reset_code =
1205 DCCP_RESET_CODE_NO_CONNECTION;
1206 dccp_v4_ctl_send_reset(skb);
1210 /* Discard frame. */
1219 inet_twsk_put((struct inet_timewait_sock *)sk);
1220 goto no_dccp_socket;
1223 static int dccp_v4_init_sock(struct sock *sk)
1225 struct dccp_sock *dp = dccp_sk(sk);
1226 static int dccp_ctl_socket_init = 1;
1228 dccp_options_init(&dp->dccps_options);
1229 do_gettimeofday(&dp->dccps_epoch);
1231 if (dp->dccps_options.dccpo_send_ack_vector) {
1232 dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN,
1234 if (dp->dccps_hc_rx_ackvec == NULL)
1239 * FIXME: We're hardcoding the CCID, and doing this at this point makes
1240 * the listening (master) sock get CCID control blocks, which is not
1241 * necessary, but for now, to not mess with the test userspace apps,
1242 * lets leave it here, later the real solution is to do this in a
1243 * setsockopt(CCIDs-I-want/accept). -acme
1245 if (likely(!dccp_ctl_socket_init)) {
1246 dp->dccps_hc_rx_ccid = ccid_init(dp->dccps_options.dccpo_rx_ccid,
1248 dp->dccps_hc_tx_ccid = ccid_init(dp->dccps_options.dccpo_tx_ccid,
1250 if (dp->dccps_hc_rx_ccid == NULL ||
1251 dp->dccps_hc_tx_ccid == NULL) {
1252 ccid_exit(dp->dccps_hc_rx_ccid, sk);
1253 ccid_exit(dp->dccps_hc_tx_ccid, sk);
1254 if (dp->dccps_options.dccpo_send_ack_vector) {
1255 dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
1256 dp->dccps_hc_rx_ackvec = NULL;
1258 dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
1262 dccp_ctl_socket_init = 0;
1264 dccp_init_xmit_timers(sk);
1265 inet_csk(sk)->icsk_rto = DCCP_TIMEOUT_INIT;
1266 sk->sk_state = DCCP_CLOSED;
1267 sk->sk_write_space = dccp_write_space;
1268 dp->dccps_mss_cache = 536;
1269 dp->dccps_role = DCCP_ROLE_UNDEFINED;
1270 dp->dccps_service = DCCP_SERVICE_INVALID_VALUE;
1275 static int dccp_v4_destroy_sock(struct sock *sk)
1277 struct dccp_sock *dp = dccp_sk(sk);
1280 * DCCP doesn't use sk_qrite_queue, just sk_send_head
1281 * for retransmissions
1283 if (sk->sk_send_head != NULL) {
1284 kfree_skb(sk->sk_send_head);
1285 sk->sk_send_head = NULL;
1288 /* Clean up a referenced DCCP bind bucket. */
1289 if (inet_csk(sk)->icsk_bind_hash != NULL)
1290 inet_put_port(&dccp_hashinfo, sk);
1292 if (dp->dccps_service_list != NULL) {
1293 kfree(dp->dccps_service_list);
1294 dp->dccps_service_list = NULL;
1297 ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
1298 ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
1299 if (dp->dccps_options.dccpo_send_ack_vector) {
1300 dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
1301 dp->dccps_hc_rx_ackvec = NULL;
1303 ccid_exit(dp->dccps_hc_rx_ccid, sk);
1304 ccid_exit(dp->dccps_hc_tx_ccid, sk);
1305 dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
1310 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1312 kfree(inet_rsk(req)->opt);
1315 static struct request_sock_ops dccp_request_sock_ops = {
1317 .obj_size = sizeof(struct dccp_request_sock),
1318 .rtx_syn_ack = dccp_v4_send_response,
1319 .send_ack = dccp_v4_reqsk_send_ack,
1320 .destructor = dccp_v4_reqsk_destructor,
1321 .send_reset = dccp_v4_ctl_send_reset,
1324 struct proto dccp_v4_prot = {
1326 .owner = THIS_MODULE,
1327 .close = dccp_close,
1328 .connect = dccp_v4_connect,
1329 .disconnect = dccp_disconnect,
1330 .ioctl = dccp_ioctl,
1331 .init = dccp_v4_init_sock,
1332 .setsockopt = dccp_setsockopt,
1333 .getsockopt = dccp_getsockopt,
1334 .sendmsg = dccp_sendmsg,
1335 .recvmsg = dccp_recvmsg,
1336 .backlog_rcv = dccp_v4_do_rcv,
1337 .hash = dccp_v4_hash,
1338 .unhash = dccp_v4_unhash,
1339 .accept = inet_csk_accept,
1340 .get_port = dccp_v4_get_port,
1341 .shutdown = dccp_shutdown,
1342 .destroy = dccp_v4_destroy_sock,
1343 .orphan_count = &dccp_orphan_count,
1344 .max_header = MAX_DCCP_HEADER,
1345 .obj_size = sizeof(struct dccp_sock),
1346 .rsk_prot = &dccp_request_sock_ops,
1347 .twsk_obj_size = sizeof(struct inet_timewait_sock),