Merge master.kernel.org:/pub/scm/linux/kernel/git/acme/net-2.6
[sfrench/cifs-2.6.git] / net / dccp / ipv4.c
1 /*
2  *  net/dccp/ipv4.c
3  *
4  *  An implementation of the DCCP protocol
5  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6  *
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.
11  */
12
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>
19
20 #include <net/icmp.h>
21 #include <net/inet_hashtables.h>
22 #include <net/sock.h>
23 #include <net/tcp_states.h>
24 #include <net/xfrm.h>
25
26 #include "ccid.h"
27 #include "dccp.h"
28
29 struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
30         .lhash_lock     = RW_LOCK_UNLOCKED,
31         .lhash_users    = ATOMIC_INIT(0),
32         .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
33         .portalloc_lock = SPIN_LOCK_UNLOCKED,
34         .port_rover     = 1024 - 1,
35 };
36
37 EXPORT_SYMBOL_GPL(dccp_hashinfo);
38
39 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
40 {
41         return inet_csk_get_port(&dccp_hashinfo, sk, snum);
42 }
43
44 static void dccp_v4_hash(struct sock *sk)
45 {
46         inet_hash(&dccp_hashinfo, sk);
47 }
48
49 static void dccp_v4_unhash(struct sock *sk)
50 {
51         inet_unhash(&dccp_hashinfo, sk);
52 }
53
54 /* called with local bh disabled */
55 static int __dccp_v4_check_established(struct sock *sk, const __u16 lport,
56                                       struct inet_timewait_sock **twp)
57 {
58         struct inet_sock *inet = inet_sk(sk);
59         const u32 daddr = inet->rcv_saddr;
60         const u32 saddr = inet->daddr;
61         const int dif = sk->sk_bound_dev_if;
62         INET_ADDR_COOKIE(acookie, saddr, daddr)
63         const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
64         const int hash = inet_ehashfn(daddr, lport, saddr, inet->dport,
65                                       dccp_hashinfo.ehash_size);
66         struct inet_ehash_bucket *head = &dccp_hashinfo.ehash[hash];
67         const struct sock *sk2;
68         const struct hlist_node *node;
69         struct inet_timewait_sock *tw;
70
71         write_lock(&head->lock);
72
73         /* Check TIME-WAIT sockets first. */
74         sk_for_each(sk2, node, &(head + dccp_hashinfo.ehash_size)->chain) {
75                 tw = inet_twsk(sk2);
76
77                 if (INET_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif))
78                         goto not_unique;
79         }
80         tw = NULL;
81
82         /* And established part... */
83         sk_for_each(sk2, node, &head->chain) {
84                 if (INET_MATCH(sk2, acookie, saddr, daddr, ports, dif))
85                         goto not_unique;
86         }
87
88         /* Must record num and sport now. Otherwise we will see
89          * in hash table socket with a funny identity. */
90         inet->num = lport;
91         inet->sport = htons(lport);
92         sk->sk_hashent = hash;
93         BUG_TRAP(sk_unhashed(sk));
94         __sk_add_node(sk, &head->chain);
95         sock_prot_inc_use(sk->sk_prot);
96         write_unlock(&head->lock);
97
98         if (twp != NULL) {
99                 *twp = tw;
100                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
101         } else if (tw != NULL) {
102                 /* Silly. Should hash-dance instead... */
103                 inet_twsk_deschedule(tw, &dccp_death_row);
104                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
105
106                 inet_twsk_put(tw);
107         }
108
109         return 0;
110
111 not_unique:
112         write_unlock(&head->lock);
113         return -EADDRNOTAVAIL;
114 }
115
116 /*
117  * Bind a port for a connect operation and hash it.
118  */
119 static int dccp_v4_hash_connect(struct sock *sk)
120 {
121         const unsigned short snum = inet_sk(sk)->num;
122         struct inet_bind_hashbucket *head;
123         struct inet_bind_bucket *tb;
124         int ret;
125
126         if (snum == 0) {
127                 int rover;
128                 int low = sysctl_local_port_range[0];
129                 int high = sysctl_local_port_range[1];
130                 int remaining = (high - low) + 1;
131                 struct hlist_node *node;
132                 struct inet_timewait_sock *tw = NULL;
133
134                 local_bh_disable();
135
136                 /* TODO. Actually it is not so bad idea to remove
137                  * dccp_hashinfo.portalloc_lock before next submission to
138                  * Linus.
139                  * As soon as we touch this place at all it is time to think.
140                  *
141                  * Now it protects single _advisory_ variable
142                  * dccp_hashinfo.port_rover, hence it is mostly useless.
143                  * Code will work nicely if we just delete it, but
144                  * I am afraid in contented case it will work not better or
145                  * even worse: another cpu just will hit the same bucket
146                  * and spin there.
147                  * So some cpu salt could remove both contention and
148                  * memory pingpong. Any ideas how to do this in a nice way?
149                  */
150                 spin_lock(&dccp_hashinfo.portalloc_lock);
151                 rover = dccp_hashinfo.port_rover;
152
153                 do {
154                         rover++;
155                         if ((rover < low) || (rover > high))
156                                 rover = low;
157                         head = &dccp_hashinfo.bhash[inet_bhashfn(rover,
158                                                     dccp_hashinfo.bhash_size)];
159                         spin_lock(&head->lock);
160
161                         /* Does not bother with rcv_saddr checks,
162                          * because the established check is already
163                          * unique enough.
164                          */
165                         inet_bind_bucket_for_each(tb, node, &head->chain) {
166                                 if (tb->port == rover) {
167                                         BUG_TRAP(!hlist_empty(&tb->owners));
168                                         if (tb->fastreuse >= 0)
169                                                 goto next_port;
170                                         if (!__dccp_v4_check_established(sk,
171                                                                          rover,
172                                                                          &tw))
173                                                 goto ok;
174                                         goto next_port;
175                                 }
176                         }
177
178                         tb = inet_bind_bucket_create(dccp_hashinfo.bind_bucket_cachep,
179                                                      head, rover);
180                         if (tb == NULL) {
181                                 spin_unlock(&head->lock);
182                                 break;
183                         }
184                         tb->fastreuse = -1;
185                         goto ok;
186
187                 next_port:
188                         spin_unlock(&head->lock);
189                 } while (--remaining > 0);
190                 dccp_hashinfo.port_rover = rover;
191                 spin_unlock(&dccp_hashinfo.portalloc_lock);
192
193                 local_bh_enable();
194
195                 return -EADDRNOTAVAIL;
196
197 ok:
198                 /* All locks still held and bhs disabled */
199                 dccp_hashinfo.port_rover = rover;
200                 spin_unlock(&dccp_hashinfo.portalloc_lock);
201
202                 inet_bind_hash(sk, tb, rover);
203                 if (sk_unhashed(sk)) {
204                         inet_sk(sk)->sport = htons(rover);
205                         __inet_hash(&dccp_hashinfo, sk, 0);
206                 }
207                 spin_unlock(&head->lock);
208
209                 if (tw != NULL) {
210                         inet_twsk_deschedule(tw, &dccp_death_row);
211                         inet_twsk_put(tw);
212                 }
213
214                 ret = 0;
215                 goto out;
216         }
217
218         head = &dccp_hashinfo.bhash[inet_bhashfn(snum,
219                                                  dccp_hashinfo.bhash_size)];
220         tb   = inet_csk(sk)->icsk_bind_hash;
221         spin_lock_bh(&head->lock);
222         if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
223                 __inet_hash(&dccp_hashinfo, sk, 0);
224                 spin_unlock_bh(&head->lock);
225                 return 0;
226         } else {
227                 spin_unlock(&head->lock);
228                 /* No definite answer... Walk to established hash table */
229                 ret = __dccp_v4_check_established(sk, snum, NULL);
230 out:
231                 local_bh_enable();
232                 return ret;
233         }
234 }
235
236 static int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
237                            int addr_len)
238 {
239         struct inet_sock *inet = inet_sk(sk);
240         struct dccp_sock *dp = dccp_sk(sk);
241         const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
242         struct rtable *rt;
243         u32 daddr, nexthop;
244         int tmp;
245         int err;
246
247         dp->dccps_role = DCCP_ROLE_CLIENT;
248
249         if (addr_len < sizeof(struct sockaddr_in))
250                 return -EINVAL;
251
252         if (usin->sin_family != AF_INET)
253                 return -EAFNOSUPPORT;
254
255         nexthop = daddr = usin->sin_addr.s_addr;
256         if (inet->opt != NULL && inet->opt->srr) {
257                 if (daddr == 0)
258                         return -EINVAL;
259                 nexthop = inet->opt->faddr;
260         }
261
262         tmp = ip_route_connect(&rt, nexthop, inet->saddr,
263                                RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
264                                IPPROTO_DCCP,
265                                inet->sport, usin->sin_port, sk);
266         if (tmp < 0)
267                 return tmp;
268
269         if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
270                 ip_rt_put(rt);
271                 return -ENETUNREACH;
272         }
273
274         if (inet->opt == NULL || !inet->opt->srr)
275                 daddr = rt->rt_dst;
276
277         if (inet->saddr == 0)
278                 inet->saddr = rt->rt_src;
279         inet->rcv_saddr = inet->saddr;
280
281         inet->dport = usin->sin_port;
282         inet->daddr = daddr;
283
284         dp->dccps_ext_header_len = 0;
285         if (inet->opt != NULL)
286                 dp->dccps_ext_header_len = inet->opt->optlen;
287         /*
288          * Socket identity is still unknown (sport may be zero).
289          * However we set state to DCCP_REQUESTING and not releasing socket
290          * lock select source port, enter ourselves into the hash tables and
291          * complete initialization after this.
292          */
293         dccp_set_state(sk, DCCP_REQUESTING);
294         err = dccp_v4_hash_connect(sk);
295         if (err != 0)
296                 goto failure;
297
298         err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
299         if (err != 0)
300                 goto failure;
301
302         /* OK, now commit destination to socket.  */
303         sk_setup_caps(sk, &rt->u.dst);
304
305         dp->dccps_gar =
306                 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
307                                                             inet->daddr,
308                                                             inet->sport,
309                                                             usin->sin_port);
310         dccp_update_gss(sk, dp->dccps_iss);
311
312         /*
313          * SWL and AWL are initially adjusted so that they are not less than
314          * the initial Sequence Numbers received and sent, respectively:
315          *      SWL := max(GSR + 1 - floor(W/4), ISR),
316          *      AWL := max(GSS - W' + 1, ISS).
317          * These adjustments MUST be applied only at the beginning of the
318          * connection.
319          */
320         dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
321
322         inet->id = dp->dccps_iss ^ jiffies;
323
324         err = dccp_connect(sk);
325         rt = NULL;
326         if (err != 0)
327                 goto failure;
328 out:
329         return err;
330 failure:
331         /*
332          * This unhashes the socket and releases the local port, if necessary.
333          */
334         dccp_set_state(sk, DCCP_CLOSED);
335         ip_rt_put(rt);
336         sk->sk_route_caps = 0;
337         inet->dport = 0;
338         goto out;
339 }
340
341 /*
342  * This routine does path mtu discovery as defined in RFC1191.
343  */
344 static inline void dccp_do_pmtu_discovery(struct sock *sk,
345                                           const struct iphdr *iph,
346                                           u32 mtu)
347 {
348         struct dst_entry *dst;
349         const struct inet_sock *inet = inet_sk(sk);
350         const struct dccp_sock *dp = dccp_sk(sk);
351
352         /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
353          * send out by Linux are always < 576bytes so they should go through
354          * unfragmented).
355          */
356         if (sk->sk_state == DCCP_LISTEN)
357                 return;
358
359         /* We don't check in the destentry if pmtu discovery is forbidden
360          * on this route. We just assume that no packet_to_big packets
361          * are send back when pmtu discovery is not active.
362          * There is a small race when the user changes this flag in the
363          * route, but I think that's acceptable.
364          */
365         if ((dst = __sk_dst_check(sk, 0)) == NULL)
366                 return;
367
368         dst->ops->update_pmtu(dst, mtu);
369
370         /* Something is about to be wrong... Remember soft error
371          * for the case, if this connection will not able to recover.
372          */
373         if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
374                 sk->sk_err_soft = EMSGSIZE;
375
376         mtu = dst_mtu(dst);
377
378         if (inet->pmtudisc != IP_PMTUDISC_DONT &&
379             dp->dccps_pmtu_cookie > mtu) {
380                 dccp_sync_mss(sk, mtu);
381
382                 /*
383                  * From: draft-ietf-dccp-spec-11.txt
384                  *
385                  *      DCCP-Sync packets are the best choice for upward
386                  *      probing, since DCCP-Sync probes do not risk application
387                  *      data loss.
388                  */
389                 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
390         } /* else let the usual retransmit timer handle it */
391 }
392
393 static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
394 {
395         int err;
396         struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
397         const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
398                                      sizeof(struct dccp_hdr_ext) +
399                                      sizeof(struct dccp_hdr_ack_bits);
400         struct sk_buff *skb;
401
402         if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
403                 return;
404
405         skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
406         if (skb == NULL)
407                 return;
408
409         /* Reserve space for headers. */
410         skb_reserve(skb, MAX_DCCP_HEADER);
411
412         skb->dst = dst_clone(rxskb->dst);
413
414         skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
415         dh = dccp_hdr(skb);
416         memset(dh, 0, dccp_hdr_ack_len);
417
418         /* Build DCCP header and checksum it. */
419         dh->dccph_type     = DCCP_PKT_ACK;
420         dh->dccph_sport    = rxdh->dccph_dport;
421         dh->dccph_dport    = rxdh->dccph_sport;
422         dh->dccph_doff     = dccp_hdr_ack_len / 4;
423         dh->dccph_x        = 1;
424
425         dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
426         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
427                          DCCP_SKB_CB(rxskb)->dccpd_seq);
428
429         bh_lock_sock(dccp_ctl_socket->sk);
430         err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
431                                     rxskb->nh.iph->daddr,
432                                     rxskb->nh.iph->saddr, NULL);
433         bh_unlock_sock(dccp_ctl_socket->sk);
434
435         if (err == NET_XMIT_CN || err == 0) {
436                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
437                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
438         }
439 }
440
441 static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
442                                    struct request_sock *req)
443 {
444         dccp_v4_ctl_send_ack(skb);
445 }
446
447 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
448                                  struct dst_entry *dst)
449 {
450         int err = -1;
451         struct sk_buff *skb;
452
453         /* First, grab a route. */
454         
455         if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
456                 goto out;
457
458         skb = dccp_make_response(sk, dst, req);
459         if (skb != NULL) {
460                 const struct inet_request_sock *ireq = inet_rsk(req);
461
462                 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
463                                             ireq->rmt_addr,
464                                             ireq->opt);
465                 if (err == NET_XMIT_CN)
466                         err = 0;
467         }
468
469 out:
470         dst_release(dst);
471         return err;
472 }
473
474 /*
475  * This routine is called by the ICMP module when it gets some sort of error
476  * condition. If err < 0 then the socket should be closed and the error
477  * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
478  * After adjustment header points to the first 8 bytes of the tcp header. We
479  * need to find the appropriate port.
480  *
481  * The locking strategy used here is very "optimistic". When someone else
482  * accesses the socket the ICMP is just dropped and for some paths there is no
483  * check at all. A more general error queue to queue errors for later handling
484  * is probably better.
485  */
486 void dccp_v4_err(struct sk_buff *skb, u32 info)
487 {
488         const struct iphdr *iph = (struct iphdr *)skb->data;
489         const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
490                                                         (iph->ihl << 2));
491         struct dccp_sock *dp;
492         struct inet_sock *inet;
493         const int type = skb->h.icmph->type;
494         const int code = skb->h.icmph->code;
495         struct sock *sk;
496         __u64 seq;
497         int err;
498
499         if (skb->len < (iph->ihl << 2) + 8) {
500                 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
501                 return;
502         }
503
504         sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
505                          iph->saddr, dh->dccph_sport, inet_iif(skb));
506         if (sk == NULL) {
507                 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
508                 return;
509         }
510
511         if (sk->sk_state == DCCP_TIME_WAIT) {
512                 inet_twsk_put((struct inet_timewait_sock *)sk);
513                 return;
514         }
515
516         bh_lock_sock(sk);
517         /* If too many ICMPs get dropped on busy
518          * servers this needs to be solved differently.
519          */
520         if (sock_owned_by_user(sk))
521                 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
522
523         if (sk->sk_state == DCCP_CLOSED)
524                 goto out;
525
526         dp = dccp_sk(sk);
527         seq = dccp_hdr_seq(skb);
528         if (sk->sk_state != DCCP_LISTEN &&
529             !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
530                 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
531                 goto out;
532         }
533
534         switch (type) {
535         case ICMP_SOURCE_QUENCH:
536                 /* Just silently ignore these. */
537                 goto out;
538         case ICMP_PARAMETERPROB:
539                 err = EPROTO;
540                 break;
541         case ICMP_DEST_UNREACH:
542                 if (code > NR_ICMP_UNREACH)
543                         goto out;
544
545                 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
546                         if (!sock_owned_by_user(sk))
547                                 dccp_do_pmtu_discovery(sk, iph, info);
548                         goto out;
549                 }
550
551                 err = icmp_err_convert[code].errno;
552                 break;
553         case ICMP_TIME_EXCEEDED:
554                 err = EHOSTUNREACH;
555                 break;
556         default:
557                 goto out;
558         }
559
560         switch (sk->sk_state) {
561                 struct request_sock *req , **prev;
562         case DCCP_LISTEN:
563                 if (sock_owned_by_user(sk))
564                         goto out;
565                 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
566                                           iph->daddr, iph->saddr);
567                 if (!req)
568                         goto out;
569
570                 /*
571                  * ICMPs are not backlogged, hence we cannot get an established
572                  * socket here.
573                  */
574                 BUG_TRAP(!req->sk);
575
576                 if (seq != dccp_rsk(req)->dreq_iss) {
577                         NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
578                         goto out;
579                 }
580                 /*
581                  * Still in RESPOND, just remove it silently.
582                  * There is no good way to pass the error to the newly
583                  * created socket, and POSIX does not want network
584                  * errors returned from accept().
585                  */
586                 inet_csk_reqsk_queue_drop(sk, req, prev);
587                 goto out;
588
589         case DCCP_REQUESTING:
590         case DCCP_RESPOND:
591                 if (!sock_owned_by_user(sk)) {
592                         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
593                         sk->sk_err = err;
594
595                         sk->sk_error_report(sk);
596
597                         dccp_done(sk);
598                 } else
599                         sk->sk_err_soft = err;
600                 goto out;
601         }
602
603         /* If we've already connected we will keep trying
604          * until we time out, or the user gives up.
605          *
606          * rfc1122 4.2.3.9 allows to consider as hard errors
607          * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
608          * but it is obsoleted by pmtu discovery).
609          *
610          * Note, that in modern internet, where routing is unreliable
611          * and in each dark corner broken firewalls sit, sending random
612          * errors ordered by their masters even this two messages finally lose
613          * their original sense (even Linux sends invalid PORT_UNREACHs)
614          *
615          * Now we are in compliance with RFCs.
616          *                                                      --ANK (980905)
617          */
618
619         inet = inet_sk(sk);
620         if (!sock_owned_by_user(sk) && inet->recverr) {
621                 sk->sk_err = err;
622                 sk->sk_error_report(sk);
623         } else /* Only an error on timeout */
624                 sk->sk_err_soft = err;
625 out:
626         bh_unlock_sock(sk);
627         sock_put(sk);
628 }
629
630 int dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code)
631 {
632         struct sk_buff *skb;
633         /*
634          * FIXME: what if rebuild_header fails?
635          * Should we be doing a rebuild_header here?
636          */
637         int err = inet_sk_rebuild_header(sk);
638
639         if (err != 0)
640                 return err;
641
642         skb = dccp_make_reset(sk, sk->sk_dst_cache, code);
643         if (skb != NULL) {
644                 const struct dccp_sock *dp = dccp_sk(sk);
645                 const struct inet_sock *inet = inet_sk(sk);
646
647                 err = ip_build_and_send_pkt(skb, sk,
648                                             inet->saddr, inet->daddr, NULL);
649                 if (err == NET_XMIT_CN)
650                         err = 0;
651
652                 ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
653                 ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
654         }
655
656         return err;
657 }
658
659 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
660                                         const struct sk_buff *skb)
661 {
662         return secure_dccp_sequence_number(skb->nh.iph->daddr,
663                                            skb->nh.iph->saddr,
664                                            dccp_hdr(skb)->dccph_dport,
665                                            dccp_hdr(skb)->dccph_sport);
666 }
667
668 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
669 {
670         struct inet_request_sock *ireq;
671         struct dccp_sock dp;
672         struct request_sock *req;
673         struct dccp_request_sock *dreq;
674         const __u32 saddr = skb->nh.iph->saddr;
675         const __u32 daddr = skb->nh.iph->daddr;
676         struct dst_entry *dst = NULL;
677
678         /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
679         if (((struct rtable *)skb->dst)->rt_flags &
680             (RTCF_BROADCAST | RTCF_MULTICAST))
681                 goto drop;
682
683         /*
684          * TW buckets are converted to open requests without
685          * limitations, they conserve resources and peer is
686          * evidently real one.
687          */
688         if (inet_csk_reqsk_queue_is_full(sk))
689                 goto drop;
690
691         /*
692          * Accept backlog is full. If we have already queued enough
693          * of warm entries in syn queue, drop request. It is better than
694          * clogging syn queue with openreqs with exponentially increasing
695          * timeout.
696          */
697         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
698                 goto drop;
699
700         req = reqsk_alloc(sk->sk_prot->rsk_prot);
701         if (req == NULL)
702                 goto drop;
703
704         /* FIXME: process options */
705
706         dccp_openreq_init(req, &dp, skb);
707
708         ireq = inet_rsk(req);
709         ireq->loc_addr = daddr;
710         ireq->rmt_addr = saddr;
711         /* FIXME: Merge Aristeu's option parsing code when ready */
712         req->rcv_wnd    = 100; /* Fake, option parsing will get the
713                                   right value */
714         ireq->opt       = NULL;
715
716         /* 
717          * Step 3: Process LISTEN state
718          *
719          * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
720          *
721          * In fact we defer setting S.GSR, S.SWL, S.SWH to
722          * dccp_create_openreq_child.
723          */
724         dreq = dccp_rsk(req);
725         dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
726         dreq->dreq_iss = dccp_v4_init_sequence(sk, skb);
727         dreq->dreq_service = dccp_hdr_request(skb)->dccph_req_service;
728
729         if (dccp_v4_send_response(sk, req, dst))
730                 goto drop_and_free;
731
732         inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
733         return 0;
734
735 drop_and_free:
736         /*
737          * FIXME: should be reqsk_free after implementing req->rsk_ops
738          */
739         __reqsk_free(req);
740 drop:
741         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
742         return -1;
743 }
744
745 /*
746  * The three way handshake has completed - we got a valid ACK or DATAACK -
747  * now create the new socket.
748  *
749  * This is the equivalent of TCP's tcp_v4_syn_recv_sock
750  */
751 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
752                                        struct request_sock *req,
753                                        struct dst_entry *dst)
754 {
755         struct inet_request_sock *ireq;
756         struct inet_sock *newinet;
757         struct dccp_sock *newdp;
758         struct sock *newsk;
759
760         if (sk_acceptq_is_full(sk))
761                 goto exit_overflow;
762
763         if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
764                 goto exit;
765
766         newsk = dccp_create_openreq_child(sk, req, skb);
767         if (newsk == NULL)
768                 goto exit;
769
770         sk_setup_caps(newsk, dst);
771
772         newdp              = dccp_sk(newsk);
773         newinet            = inet_sk(newsk);
774         ireq               = inet_rsk(req);
775         newinet->daddr     = ireq->rmt_addr;
776         newinet->rcv_saddr = ireq->loc_addr;
777         newinet->saddr     = ireq->loc_addr;
778         newinet->opt       = ireq->opt;
779         ireq->opt          = NULL;
780         newinet->mc_index  = inet_iif(skb);
781         newinet->mc_ttl    = skb->nh.iph->ttl;
782         newinet->id        = jiffies;
783
784         dccp_sync_mss(newsk, dst_mtu(dst));
785
786         __inet_hash(&dccp_hashinfo, newsk, 0);
787         __inet_inherit_port(&dccp_hashinfo, sk, newsk);
788
789         return newsk;
790
791 exit_overflow:
792         NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
793 exit:
794         NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
795         dst_release(dst);
796         return NULL;
797 }
798
799 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
800 {
801         const struct dccp_hdr *dh = dccp_hdr(skb);
802         const struct iphdr *iph = skb->nh.iph;
803         struct sock *nsk;
804         struct request_sock **prev;
805         /* Find possible connection requests. */
806         struct request_sock *req = inet_csk_search_req(sk, &prev,
807                                                        dh->dccph_sport,
808                                                        iph->saddr, iph->daddr);
809         if (req != NULL)
810                 return dccp_check_req(sk, skb, req, prev);
811
812         nsk = __inet_lookup_established(&dccp_hashinfo,
813                                         iph->saddr, dh->dccph_sport,
814                                         iph->daddr, ntohs(dh->dccph_dport),
815                                         inet_iif(skb));
816         if (nsk != NULL) {
817                 if (nsk->sk_state != DCCP_TIME_WAIT) {
818                         bh_lock_sock(nsk);
819                         return nsk;
820                 }
821                 inet_twsk_put((struct inet_timewait_sock *)nsk);
822                 return NULL;
823         }
824
825         return sk;
826 }
827
828 int dccp_v4_checksum(const struct sk_buff *skb, const u32 saddr,
829                      const u32 daddr)
830 {
831         const struct dccp_hdr* dh = dccp_hdr(skb);
832         int checksum_len;
833         u32 tmp;
834
835         if (dh->dccph_cscov == 0)
836                 checksum_len = skb->len;
837         else {
838                 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
839                 checksum_len = checksum_len < skb->len ? checksum_len :
840                                                          skb->len;
841         }
842
843         tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
844         return csum_tcpudp_magic(saddr, daddr, checksum_len,
845                                  IPPROTO_DCCP, tmp);
846 }
847
848 static int dccp_v4_verify_checksum(struct sk_buff *skb,
849                                    const u32 saddr, const u32 daddr)
850 {
851         struct dccp_hdr *dh = dccp_hdr(skb);
852         int checksum_len;
853         u32 tmp;
854
855         if (dh->dccph_cscov == 0)
856                 checksum_len = skb->len;
857         else {
858                 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
859                 checksum_len = checksum_len < skb->len ? checksum_len :
860                                                          skb->len;
861         }
862         tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
863         return csum_tcpudp_magic(saddr, daddr, checksum_len,
864                                  IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
865 }
866
867 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
868                                            struct sk_buff *skb)
869 {
870         struct rtable *rt;
871         struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
872                             .nl_u = { .ip4_u =
873                                       { .daddr = skb->nh.iph->saddr,
874                                         .saddr = skb->nh.iph->daddr,
875                                         .tos = RT_CONN_FLAGS(sk) } },
876                             .proto = sk->sk_protocol,
877                             .uli_u = { .ports =
878                                        { .sport = dccp_hdr(skb)->dccph_dport,
879                                          .dport = dccp_hdr(skb)->dccph_sport }
880                                      }
881                           };
882
883         if (ip_route_output_flow(&rt, &fl, sk, 0)) {
884                 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
885                 return NULL;
886         }
887
888         return &rt->u.dst;
889 }
890
891 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
892 {
893         int err;
894         struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
895         const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
896                                        sizeof(struct dccp_hdr_ext) +
897                                        sizeof(struct dccp_hdr_reset);
898         struct sk_buff *skb;
899         struct dst_entry *dst;
900         u64 seqno;
901
902         /* Never send a reset in response to a reset. */
903         if (rxdh->dccph_type == DCCP_PKT_RESET)
904                 return;
905
906         if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
907                 return;
908
909         dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
910         if (dst == NULL)
911                 return;
912
913         skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
914         if (skb == NULL)
915                 goto out;
916
917         /* Reserve space for headers. */
918         skb_reserve(skb, MAX_DCCP_HEADER);
919         skb->dst = dst_clone(dst);
920
921         skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
922         dh = dccp_hdr(skb);
923         memset(dh, 0, dccp_hdr_reset_len);
924
925         /* Build DCCP header and checksum it. */
926         dh->dccph_type     = DCCP_PKT_RESET;
927         dh->dccph_sport    = rxdh->dccph_dport;
928         dh->dccph_dport    = rxdh->dccph_sport;
929         dh->dccph_doff     = dccp_hdr_reset_len / 4;
930         dh->dccph_x        = 1;
931         dccp_hdr_reset(skb)->dccph_reset_code =
932                                 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
933
934         /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
935         seqno = 0;
936         if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
937                 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
938
939         dccp_hdr_set_seq(dh, seqno);
940         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
941                          DCCP_SKB_CB(rxskb)->dccpd_seq);
942
943         dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
944                                               rxskb->nh.iph->daddr);
945
946         bh_lock_sock(dccp_ctl_socket->sk);
947         err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
948                                     rxskb->nh.iph->daddr,
949                                     rxskb->nh.iph->saddr, NULL);
950         bh_unlock_sock(dccp_ctl_socket->sk);
951
952         if (err == NET_XMIT_CN || err == 0) {
953                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
954                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
955         }
956 out:
957          dst_release(dst);
958 }
959
960 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
961 {
962         struct dccp_hdr *dh = dccp_hdr(skb);
963
964         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
965                 if (dccp_rcv_established(sk, skb, dh, skb->len))
966                         goto reset;
967                 return 0;
968         }
969
970         /*
971          *  Step 3: Process LISTEN state
972          *     If S.state == LISTEN,
973          *        If P.type == Request or P contains a valid Init Cookie
974          *              option,
975          *           * Must scan the packet's options to check for an Init
976          *              Cookie.  Only the Init Cookie is processed here,
977          *              however; other options are processed in Step 8.  This
978          *              scan need only be performed if the endpoint uses Init
979          *              Cookies *
980          *           * Generate a new socket and switch to that socket *
981          *           Set S := new socket for this port pair
982          *           S.state = RESPOND
983          *           Choose S.ISS (initial seqno) or set from Init Cookie
984          *           Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
985          *           Continue with S.state == RESPOND
986          *           * A Response packet will be generated in Step 11 *
987          *        Otherwise,
988          *           Generate Reset(No Connection) unless P.type == Reset
989          *           Drop packet and return
990          *
991          * NOTE: the check for the packet types is done in
992          *       dccp_rcv_state_process
993          */
994         if (sk->sk_state == DCCP_LISTEN) {
995                 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
996
997                 if (nsk == NULL)
998                         goto discard;
999
1000                 if (nsk != sk) {
1001                         if (dccp_child_process(sk, nsk, skb))
1002                                 goto reset;
1003                         return 0;
1004                 }
1005         }
1006
1007         if (dccp_rcv_state_process(sk, skb, dh, skb->len))
1008                 goto reset;
1009         return 0;
1010
1011 reset:
1012         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
1013         dccp_v4_ctl_send_reset(skb);
1014 discard:
1015         kfree_skb(skb);
1016         return 0;
1017 }
1018
1019 static inline int dccp_invalid_packet(struct sk_buff *skb)
1020 {
1021         const struct dccp_hdr *dh;
1022
1023         if (skb->pkt_type != PACKET_HOST)
1024                 return 1;
1025
1026         if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
1027                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
1028                 return 1;
1029         }
1030
1031         dh = dccp_hdr(skb);
1032
1033         /* If the packet type is not understood, drop packet and return */
1034         if (dh->dccph_type >= DCCP_PKT_INVALID) {
1035                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
1036                 return 1;
1037         }
1038
1039         /*
1040          * If P.Data Offset is too small for packet type, or too large for
1041          * packet, drop packet and return
1042          */
1043         if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
1044                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1045                                             "too small 1\n",
1046                                dh->dccph_doff);
1047                 return 1;
1048         }
1049
1050         if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
1051                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1052                                             "too small 2\n",
1053                                dh->dccph_doff);
1054                 return 1;
1055         }
1056
1057         dh = dccp_hdr(skb);
1058
1059         /*
1060          * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
1061          * has short sequence numbers), drop packet and return
1062          */
1063         if (dh->dccph_x == 0 &&
1064             dh->dccph_type != DCCP_PKT_DATA &&
1065             dh->dccph_type != DCCP_PKT_ACK &&
1066             dh->dccph_type != DCCP_PKT_DATAACK) {
1067                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
1068                                             "nor DataAck and P.X == 0\n",
1069                                dccp_packet_name(dh->dccph_type));
1070                 return 1;
1071         }
1072
1073         /* If the header checksum is incorrect, drop packet and return */
1074         if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
1075                                     skb->nh.iph->daddr) < 0) {
1076                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: header checksum is "
1077                                             "incorrect\n");
1078                 return 1;
1079         }
1080
1081         return 0;
1082 }
1083
1084 /* this is called when real data arrives */
1085 int dccp_v4_rcv(struct sk_buff *skb)
1086 {
1087         const struct dccp_hdr *dh;
1088         struct sock *sk;
1089         int rc;
1090
1091         /* Step 1: Check header basics: */
1092
1093         if (dccp_invalid_packet(skb))
1094                 goto discard_it;
1095
1096         dh = dccp_hdr(skb);
1097 #if 0
1098         /*
1099          * Use something like this to simulate some DATA/DATAACK loss to test
1100          * dccp_ackpkts_add, you'll get something like this on a session that
1101          * sends 10 DATA/DATAACK packets:
1102          *
1103          * ackpkts_print: 281473596467422 |0,0|3,0|0,0|3,0|0,0|3,0|0,0|3,0|0,1|
1104          *
1105          * 0, 0 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == just this packet
1106          * 0, 1 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == two adjacent packets
1107          *                                                 with the same state
1108          * 3, 0 means: DCCP_ACKPKTS_STATE_NOT_RECEIVED, RLE == just this packet
1109          *
1110          * So...
1111          *
1112          * 281473596467422 was received
1113          * 281473596467421 was not received
1114          * 281473596467420 was received
1115          * 281473596467419 was not received
1116          * 281473596467418 was received
1117          * 281473596467417 was not received
1118          * 281473596467416 was received
1119          * 281473596467415 was not received
1120          * 281473596467414 was received
1121          * 281473596467413 was received (this one was the 3way handshake
1122          *                               RESPONSE)
1123          *
1124          */
1125         if (dh->dccph_type == DCCP_PKT_DATA ||
1126             dh->dccph_type == DCCP_PKT_DATAACK) {
1127                 static int discard = 0;
1128
1129                 if (discard) {
1130                         discard = 0;
1131                         goto discard_it;
1132                 }
1133                 discard = 1;
1134         }
1135 #endif
1136         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(skb);
1137         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
1138
1139         dccp_pr_debug("%8.8s "
1140                       "src=%u.%u.%u.%u@%-5d "
1141                       "dst=%u.%u.%u.%u@%-5d seq=%llu",
1142                       dccp_packet_name(dh->dccph_type),
1143                       NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
1144                       NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
1145                       (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
1146
1147         if (dccp_packet_without_ack(skb)) {
1148                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
1149                 dccp_pr_debug_cat("\n");
1150         } else {
1151                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
1152                 dccp_pr_debug_cat(", ack=%llu\n",
1153                                   (unsigned long long)
1154                                   DCCP_SKB_CB(skb)->dccpd_ack_seq);
1155         }
1156
1157         /* Step 2:
1158          *      Look up flow ID in table and get corresponding socket */
1159         sk = __inet_lookup(&dccp_hashinfo,
1160                            skb->nh.iph->saddr, dh->dccph_sport,
1161                            skb->nh.iph->daddr, ntohs(dh->dccph_dport),
1162                            inet_iif(skb));
1163
1164         /* 
1165          * Step 2:
1166          *      If no socket ...
1167          *              Generate Reset(No Connection) unless P.type == Reset
1168          *              Drop packet and return
1169          */
1170         if (sk == NULL) {
1171                 dccp_pr_debug("failed to look up flow ID in table and "
1172                               "get corresponding socket\n");
1173                 goto no_dccp_socket;
1174         }
1175
1176         /* 
1177          * Step 2:
1178          *      ... or S.state == TIMEWAIT,
1179          *              Generate Reset(No Connection) unless P.type == Reset
1180          *              Drop packet and return
1181          */
1182                
1183         if (sk->sk_state == DCCP_TIME_WAIT) {
1184                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
1185                               "do_time_wait\n");
1186                 goto do_time_wait;
1187         }
1188
1189         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
1190                 dccp_pr_debug("xfrm4_policy_check failed\n");
1191                 goto discard_and_relse;
1192         }
1193
1194         if (sk_filter(sk, skb, 0)) {
1195                 dccp_pr_debug("sk_filter failed\n");
1196                 goto discard_and_relse;
1197         }
1198
1199         skb->dev = NULL;
1200
1201         bh_lock_sock(sk);
1202         rc = 0;
1203         if (!sock_owned_by_user(sk))
1204                 rc = dccp_v4_do_rcv(sk, skb);
1205         else
1206                 sk_add_backlog(sk, skb);
1207         bh_unlock_sock(sk);
1208
1209         sock_put(sk);
1210         return rc;
1211
1212 no_dccp_socket:
1213         if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1214                 goto discard_it;
1215         /*
1216          * Step 2:
1217          *              Generate Reset(No Connection) unless P.type == Reset
1218          *              Drop packet and return
1219          */
1220         if (dh->dccph_type != DCCP_PKT_RESET) {
1221                 DCCP_SKB_CB(skb)->dccpd_reset_code =
1222                                         DCCP_RESET_CODE_NO_CONNECTION;
1223                 dccp_v4_ctl_send_reset(skb);
1224         }
1225
1226 discard_it:
1227         /* Discard frame. */
1228         kfree_skb(skb);
1229         return 0;
1230
1231 discard_and_relse:
1232         sock_put(sk);
1233         goto discard_it;
1234
1235 do_time_wait:
1236         inet_twsk_put((struct inet_timewait_sock *)sk);
1237         goto no_dccp_socket;
1238 }
1239
1240 static int dccp_v4_init_sock(struct sock *sk)
1241 {
1242         struct dccp_sock *dp = dccp_sk(sk);
1243         static int dccp_ctl_socket_init = 1;
1244
1245         dccp_options_init(&dp->dccps_options);
1246         do_gettimeofday(&dp->dccps_epoch);
1247
1248         if (dp->dccps_options.dccpo_send_ack_vector) {
1249                 dp->dccps_hc_rx_ackpkts =
1250                         dccp_ackpkts_alloc(DCCP_MAX_ACK_VECTOR_LEN,
1251                                            GFP_KERNEL);
1252
1253                 if (dp->dccps_hc_rx_ackpkts == NULL)
1254                         return -ENOMEM;
1255         }
1256
1257         /*
1258          * FIXME: We're hardcoding the CCID, and doing this at this point makes
1259          * the listening (master) sock get CCID control blocks, which is not
1260          * necessary, but for now, to not mess with the test userspace apps,
1261          * lets leave it here, later the real solution is to do this in a
1262          * setsockopt(CCIDs-I-want/accept). -acme
1263          */
1264         if (likely(!dccp_ctl_socket_init)) {
1265                 dp->dccps_hc_rx_ccid = ccid_init(dp->dccps_options.dccpo_ccid,
1266                                                  sk);
1267                 dp->dccps_hc_tx_ccid = ccid_init(dp->dccps_options.dccpo_ccid,
1268                                                  sk);
1269                 if (dp->dccps_hc_rx_ccid == NULL ||
1270                     dp->dccps_hc_tx_ccid == NULL) {
1271                         ccid_exit(dp->dccps_hc_rx_ccid, sk);
1272                         ccid_exit(dp->dccps_hc_tx_ccid, sk);
1273                         dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
1274                         dp->dccps_hc_rx_ackpkts = NULL;
1275                         dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
1276                         return -ENOMEM;
1277                 }
1278         } else
1279                 dccp_ctl_socket_init = 0;
1280
1281         dccp_init_xmit_timers(sk);
1282         inet_csk(sk)->icsk_rto = DCCP_TIMEOUT_INIT;
1283         sk->sk_state = DCCP_CLOSED;
1284         sk->sk_write_space = dccp_write_space;
1285         dp->dccps_mss_cache = 536;
1286         dp->dccps_role = DCCP_ROLE_UNDEFINED;
1287
1288         return 0;
1289 }
1290
1291 static int dccp_v4_destroy_sock(struct sock *sk)
1292 {
1293         struct dccp_sock *dp = dccp_sk(sk);
1294
1295         /*
1296          * DCCP doesn't use sk_qrite_queue, just sk_send_head
1297          * for retransmissions
1298          */
1299         if (sk->sk_send_head != NULL) {
1300                 kfree_skb(sk->sk_send_head);
1301                 sk->sk_send_head = NULL;
1302         }
1303
1304         /* Clean up a referenced DCCP bind bucket. */
1305         if (inet_csk(sk)->icsk_bind_hash != NULL)
1306                 inet_put_port(&dccp_hashinfo, sk);
1307
1308         ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
1309         ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
1310         dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
1311         dp->dccps_hc_rx_ackpkts = NULL;
1312         ccid_exit(dp->dccps_hc_rx_ccid, sk);
1313         ccid_exit(dp->dccps_hc_tx_ccid, sk);
1314         dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
1315
1316         return 0;
1317 }
1318
1319 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1320 {
1321         kfree(inet_rsk(req)->opt);
1322 }
1323
1324 static struct request_sock_ops dccp_request_sock_ops = {
1325         .family         = PF_INET,
1326         .obj_size       = sizeof(struct dccp_request_sock),
1327         .rtx_syn_ack    = dccp_v4_send_response,
1328         .send_ack       = dccp_v4_reqsk_send_ack,
1329         .destructor     = dccp_v4_reqsk_destructor,
1330         .send_reset     = dccp_v4_ctl_send_reset,
1331 };
1332
1333 struct proto dccp_v4_prot = {
1334         .name                   = "DCCP",
1335         .owner                  = THIS_MODULE,
1336         .close                  = dccp_close,
1337         .connect                = dccp_v4_connect,
1338         .disconnect             = dccp_disconnect,
1339         .ioctl                  = dccp_ioctl,
1340         .init                   = dccp_v4_init_sock,
1341         .setsockopt             = dccp_setsockopt,
1342         .getsockopt             = dccp_getsockopt,
1343         .sendmsg                = dccp_sendmsg,
1344         .recvmsg                = dccp_recvmsg,
1345         .backlog_rcv            = dccp_v4_do_rcv,
1346         .hash                   = dccp_v4_hash,
1347         .unhash                 = dccp_v4_unhash,
1348         .accept                 = inet_csk_accept,
1349         .get_port               = dccp_v4_get_port,
1350         .shutdown               = dccp_shutdown,
1351         .destroy                = dccp_v4_destroy_sock,
1352         .orphan_count           = &dccp_orphan_count,
1353         .max_header             = MAX_DCCP_HEADER,
1354         .obj_size               = sizeof(struct dccp_sock),
1355         .rsk_prot               = &dccp_request_sock_ops,
1356         .twsk_obj_size          = sizeof(struct inet_timewait_sock),
1357 };