Merge branch 'master'
[linux-2.6] / 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 "ackvec.h"
27 #include "ccid.h"
28 #include "dccp.h"
29
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,
36 };
37
38 EXPORT_SYMBOL_GPL(dccp_hashinfo);
39
40 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
41 {
42         return inet_csk_get_port(&dccp_hashinfo, sk, snum);
43 }
44
45 static void dccp_v4_hash(struct sock *sk)
46 {
47         inet_hash(&dccp_hashinfo, sk);
48 }
49
50 static void dccp_v4_unhash(struct sock *sk)
51 {
52         inet_unhash(&dccp_hashinfo, sk);
53 }
54
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)
58 {
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;
70
71         prefetch(head->chain.first);
72         write_lock(&head->lock);
73
74         /* Check TIME-WAIT sockets first. */
75         sk_for_each(sk2, node, &(head + dccp_hashinfo.ehash_size)->chain) {
76                 tw = inet_twsk(sk2);
77
78                 if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif))
79                         goto not_unique;
80         }
81         tw = NULL;
82
83         /* And established part... */
84         sk_for_each(sk2, node, &head->chain) {
85                 if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif))
86                         goto not_unique;
87         }
88
89         /* Must record num and sport now. Otherwise we will see
90          * in hash table socket with a funny identity. */
91         inet->num = lport;
92         inet->sport = htons(lport);
93         sk->sk_hash = hash;
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);
98
99         if (twp != NULL) {
100                 *twp = tw;
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);
106
107                 inet_twsk_put(tw);
108         }
109
110         return 0;
111
112 not_unique:
113         write_unlock(&head->lock);
114         return -EADDRNOTAVAIL;
115 }
116
117 /*
118  * Bind a port for a connect operation and hash it.
119  */
120 static int dccp_v4_hash_connect(struct sock *sk)
121 {
122         const unsigned short snum = inet_sk(sk)->num;
123         struct inet_bind_hashbucket *head;
124         struct inet_bind_bucket *tb;
125         int ret;
126
127         if (snum == 0) {
128                 int rover;
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;
134
135                 local_bh_disable();
136
137                 /* TODO. Actually it is not so bad idea to remove
138                  * dccp_hashinfo.portalloc_lock before next submission to
139                  * Linus.
140                  * As soon as we touch this place at all it is time to think.
141                  *
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
147                  * and spin there.
148                  * So some cpu salt could remove both contention and
149                  * memory pingpong. Any ideas how to do this in a nice way?
150                  */
151                 spin_lock(&dccp_hashinfo.portalloc_lock);
152                 rover = dccp_hashinfo.port_rover;
153
154                 do {
155                         rover++;
156                         if ((rover < low) || (rover > high))
157                                 rover = low;
158                         head = &dccp_hashinfo.bhash[inet_bhashfn(rover,
159                                                     dccp_hashinfo.bhash_size)];
160                         spin_lock(&head->lock);
161
162                         /* Does not bother with rcv_saddr checks,
163                          * because the established check is already
164                          * unique enough.
165                          */
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)
170                                                 goto next_port;
171                                         if (!__dccp_v4_check_established(sk,
172                                                                          rover,
173                                                                          &tw))
174                                                 goto ok;
175                                         goto next_port;
176                                 }
177                         }
178
179                         tb = inet_bind_bucket_create(dccp_hashinfo.bind_bucket_cachep,
180                                                      head, rover);
181                         if (tb == NULL) {
182                                 spin_unlock(&head->lock);
183                                 break;
184                         }
185                         tb->fastreuse = -1;
186                         goto ok;
187
188                 next_port:
189                         spin_unlock(&head->lock);
190                 } while (--remaining > 0);
191                 dccp_hashinfo.port_rover = rover;
192                 spin_unlock(&dccp_hashinfo.portalloc_lock);
193
194                 local_bh_enable();
195
196                 return -EADDRNOTAVAIL;
197
198 ok:
199                 /* All locks still held and bhs disabled */
200                 dccp_hashinfo.port_rover = rover;
201                 spin_unlock(&dccp_hashinfo.portalloc_lock);
202
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);
207                 }
208                 spin_unlock(&head->lock);
209
210                 if (tw != NULL) {
211                         inet_twsk_deschedule(tw, &dccp_death_row);
212                         inet_twsk_put(tw);
213                 }
214
215                 ret = 0;
216                 goto out;
217         }
218
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);
226                 return 0;
227         } else {
228                 spin_unlock(&head->lock);
229                 /* No definite answer... Walk to established hash table */
230                 ret = __dccp_v4_check_established(sk, snum, NULL);
231 out:
232                 local_bh_enable();
233                 return ret;
234         }
235 }
236
237 static int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
238                            int addr_len)
239 {
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;
243         struct rtable *rt;
244         u32 daddr, nexthop;
245         int tmp;
246         int err;
247
248         dp->dccps_role = DCCP_ROLE_CLIENT;
249
250         if (dccp_service_not_initialized(sk))
251                 return -EPROTO;
252
253         if (addr_len < sizeof(struct sockaddr_in))
254                 return -EINVAL;
255
256         if (usin->sin_family != AF_INET)
257                 return -EAFNOSUPPORT;
258
259         nexthop = daddr = usin->sin_addr.s_addr;
260         if (inet->opt != NULL && inet->opt->srr) {
261                 if (daddr == 0)
262                         return -EINVAL;
263                 nexthop = inet->opt->faddr;
264         }
265
266         tmp = ip_route_connect(&rt, nexthop, inet->saddr,
267                                RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
268                                IPPROTO_DCCP,
269                                inet->sport, usin->sin_port, sk);
270         if (tmp < 0)
271                 return tmp;
272
273         if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
274                 ip_rt_put(rt);
275                 return -ENETUNREACH;
276         }
277
278         if (inet->opt == NULL || !inet->opt->srr)
279                 daddr = rt->rt_dst;
280
281         if (inet->saddr == 0)
282                 inet->saddr = rt->rt_src;
283         inet->rcv_saddr = inet->saddr;
284
285         inet->dport = usin->sin_port;
286         inet->daddr = daddr;
287
288         dp->dccps_ext_header_len = 0;
289         if (inet->opt != NULL)
290                 dp->dccps_ext_header_len = inet->opt->optlen;
291         /*
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.
296          */
297         dccp_set_state(sk, DCCP_REQUESTING);
298         err = dccp_v4_hash_connect(sk);
299         if (err != 0)
300                 goto failure;
301
302         err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
303         if (err != 0)
304                 goto failure;
305
306         /* OK, now commit destination to socket.  */
307         sk_setup_caps(sk, &rt->u.dst);
308
309         dp->dccps_gar =
310                 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
311                                                             inet->daddr,
312                                                             inet->sport,
313                                                             usin->sin_port);
314         dccp_update_gss(sk, dp->dccps_iss);
315
316         /*
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
322          * connection.
323          */
324         dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
325
326         inet->id = dp->dccps_iss ^ jiffies;
327
328         err = dccp_connect(sk);
329         rt = NULL;
330         if (err != 0)
331                 goto failure;
332 out:
333         return err;
334 failure:
335         /*
336          * This unhashes the socket and releases the local port, if necessary.
337          */
338         dccp_set_state(sk, DCCP_CLOSED);
339         ip_rt_put(rt);
340         sk->sk_route_caps = 0;
341         inet->dport = 0;
342         goto out;
343 }
344
345 /*
346  * This routine does path mtu discovery as defined in RFC1191.
347  */
348 static inline void dccp_do_pmtu_discovery(struct sock *sk,
349                                           const struct iphdr *iph,
350                                           u32 mtu)
351 {
352         struct dst_entry *dst;
353         const struct inet_sock *inet = inet_sk(sk);
354         const struct dccp_sock *dp = dccp_sk(sk);
355
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
358          * unfragmented).
359          */
360         if (sk->sk_state == DCCP_LISTEN)
361                 return;
362
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.
368          */
369         if ((dst = __sk_dst_check(sk, 0)) == NULL)
370                 return;
371
372         dst->ops->update_pmtu(dst, mtu);
373
374         /* Something is about to be wrong... Remember soft error
375          * for the case, if this connection will not able to recover.
376          */
377         if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
378                 sk->sk_err_soft = EMSGSIZE;
379
380         mtu = dst_mtu(dst);
381
382         if (inet->pmtudisc != IP_PMTUDISC_DONT &&
383             dp->dccps_pmtu_cookie > mtu) {
384                 dccp_sync_mss(sk, mtu);
385
386                 /*
387                  * From: draft-ietf-dccp-spec-11.txt
388                  *
389                  *      DCCP-Sync packets are the best choice for upward
390                  *      probing, since DCCP-Sync probes do not risk application
391                  *      data loss.
392                  */
393                 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
394         } /* else let the usual retransmit timer handle it */
395 }
396
397 static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
398 {
399         int err;
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);
404         struct sk_buff *skb;
405
406         if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
407                 return;
408
409         skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
410         if (skb == NULL)
411                 return;
412
413         /* Reserve space for headers. */
414         skb_reserve(skb, MAX_DCCP_HEADER);
415
416         skb->dst = dst_clone(rxskb->dst);
417
418         skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
419         dh = dccp_hdr(skb);
420         memset(dh, 0, dccp_hdr_ack_len);
421
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;
427         dh->dccph_x        = 1;
428
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);
432
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);
438
439         if (err == NET_XMIT_CN || err == 0) {
440                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
441                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
442         }
443 }
444
445 static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
446                                    struct request_sock *req)
447 {
448         dccp_v4_ctl_send_ack(skb);
449 }
450
451 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
452                                  struct dst_entry *dst)
453 {
454         int err = -1;
455         struct sk_buff *skb;
456
457         /* First, grab a route. */
458         
459         if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
460                 goto out;
461
462         skb = dccp_make_response(sk, dst, req);
463         if (skb != NULL) {
464                 const struct inet_request_sock *ireq = inet_rsk(req);
465
466                 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
467                 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
468                                             ireq->rmt_addr,
469                                             ireq->opt);
470                 if (err == NET_XMIT_CN)
471                         err = 0;
472         }
473
474 out:
475         dst_release(dst);
476         return err;
477 }
478
479 /*
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.
485  *
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.
490  */
491 void dccp_v4_err(struct sk_buff *skb, u32 info)
492 {
493         const struct iphdr *iph = (struct iphdr *)skb->data;
494         const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
495                                                         (iph->ihl << 2));
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;
500         struct sock *sk;
501         __u64 seq;
502         int err;
503
504         if (skb->len < (iph->ihl << 2) + 8) {
505                 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
506                 return;
507         }
508
509         sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
510                          iph->saddr, dh->dccph_sport, inet_iif(skb));
511         if (sk == NULL) {
512                 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
513                 return;
514         }
515
516         if (sk->sk_state == DCCP_TIME_WAIT) {
517                 inet_twsk_put((struct inet_timewait_sock *)sk);
518                 return;
519         }
520
521         bh_lock_sock(sk);
522         /* If too many ICMPs get dropped on busy
523          * servers this needs to be solved differently.
524          */
525         if (sock_owned_by_user(sk))
526                 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
527
528         if (sk->sk_state == DCCP_CLOSED)
529                 goto out;
530
531         dp = dccp_sk(sk);
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);
536                 goto out;
537         }
538
539         switch (type) {
540         case ICMP_SOURCE_QUENCH:
541                 /* Just silently ignore these. */
542                 goto out;
543         case ICMP_PARAMETERPROB:
544                 err = EPROTO;
545                 break;
546         case ICMP_DEST_UNREACH:
547                 if (code > NR_ICMP_UNREACH)
548                         goto out;
549
550                 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
551                         if (!sock_owned_by_user(sk))
552                                 dccp_do_pmtu_discovery(sk, iph, info);
553                         goto out;
554                 }
555
556                 err = icmp_err_convert[code].errno;
557                 break;
558         case ICMP_TIME_EXCEEDED:
559                 err = EHOSTUNREACH;
560                 break;
561         default:
562                 goto out;
563         }
564
565         switch (sk->sk_state) {
566                 struct request_sock *req , **prev;
567         case DCCP_LISTEN:
568                 if (sock_owned_by_user(sk))
569                         goto out;
570                 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
571                                           iph->daddr, iph->saddr);
572                 if (!req)
573                         goto out;
574
575                 /*
576                  * ICMPs are not backlogged, hence we cannot get an established
577                  * socket here.
578                  */
579                 BUG_TRAP(!req->sk);
580
581                 if (seq != dccp_rsk(req)->dreq_iss) {
582                         NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
583                         goto out;
584                 }
585                 /*
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().
590                  */
591                 inet_csk_reqsk_queue_drop(sk, req, prev);
592                 goto out;
593
594         case DCCP_REQUESTING:
595         case DCCP_RESPOND:
596                 if (!sock_owned_by_user(sk)) {
597                         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
598                         sk->sk_err = err;
599
600                         sk->sk_error_report(sk);
601
602                         dccp_done(sk);
603                 } else
604                         sk->sk_err_soft = err;
605                 goto out;
606         }
607
608         /* If we've already connected we will keep trying
609          * until we time out, or the user gives up.
610          *
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).
614          *
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)
619          *
620          * Now we are in compliance with RFCs.
621          *                                                      --ANK (980905)
622          */
623
624         inet = inet_sk(sk);
625         if (!sock_owned_by_user(sk) && inet->recverr) {
626                 sk->sk_err = err;
627                 sk->sk_error_report(sk);
628         } else /* Only an error on timeout */
629                 sk->sk_err_soft = err;
630 out:
631         bh_unlock_sock(sk);
632         sock_put(sk);
633 }
634
635 int dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code)
636 {
637         struct sk_buff *skb;
638         /*
639          * FIXME: what if rebuild_header fails?
640          * Should we be doing a rebuild_header here?
641          */
642         int err = inet_sk_rebuild_header(sk);
643
644         if (err != 0)
645                 return err;
646
647         skb = dccp_make_reset(sk, sk->sk_dst_cache, code);
648         if (skb != NULL) {
649                 const struct inet_sock *inet = inet_sk(sk);
650
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)
655                         err = 0;
656         }
657
658         return err;
659 }
660
661 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
662                                         const struct sk_buff *skb)
663 {
664         return secure_dccp_sequence_number(skb->nh.iph->daddr,
665                                            skb->nh.iph->saddr,
666                                            dccp_hdr(skb)->dccph_dport,
667                                            dccp_hdr(skb)->dccph_sport);
668 }
669
670 static inline int dccp_bad_service_code(const struct sock *sk,
671                                         const __u32 service)
672 {
673         const struct dccp_sock *dp = dccp_sk(sk);
674
675         if (dp->dccps_service == service)
676                 return 0;
677         return !dccp_list_has_service(dp->dccps_service_list, service);
678 }
679
680 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
681 {
682         struct inet_request_sock *ireq;
683         struct dccp_sock dp;
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;
692
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;
697                 goto drop;
698         }
699
700         if (dccp_bad_service_code(sk, service)) {
701                 reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
702                 goto drop;
703         }
704         /*
705          * TW buckets are converted to open requests without
706          * limitations, they conserve resources and peer is
707          * evidently real one.
708          */
709         if (inet_csk_reqsk_queue_is_full(sk))
710                 goto drop;
711
712         /*
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
716          * timeout.
717          */
718         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
719                 goto drop;
720
721         req = reqsk_alloc(sk->sk_prot->rsk_prot);
722         if (req == NULL)
723                 goto drop;
724
725         /* FIXME: process options */
726
727         dccp_openreq_init(req, &dp, skb);
728
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
734                                   right value */
735         ireq->opt       = NULL;
736
737         /* 
738          * Step 3: Process LISTEN state
739          *
740          * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
741          *
742          * In fact we defer setting S.GSR, S.SWL, S.SWH to
743          * dccp_create_openreq_child.
744          */
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;
749
750         if (dccp_v4_send_response(sk, req, dst))
751                 goto drop_and_free;
752
753         inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
754         return 0;
755
756 drop_and_free:
757         /*
758          * FIXME: should be reqsk_free after implementing req->rsk_ops
759          */
760         __reqsk_free(req);
761 drop:
762         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
763         dcb->dccpd_reset_code = reset_code;
764         return -1;
765 }
766
767 /*
768  * The three way handshake has completed - we got a valid ACK or DATAACK -
769  * now create the new socket.
770  *
771  * This is the equivalent of TCP's tcp_v4_syn_recv_sock
772  */
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)
776 {
777         struct inet_request_sock *ireq;
778         struct inet_sock *newinet;
779         struct dccp_sock *newdp;
780         struct sock *newsk;
781
782         if (sk_acceptq_is_full(sk))
783                 goto exit_overflow;
784
785         if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
786                 goto exit;
787
788         newsk = dccp_create_openreq_child(sk, req, skb);
789         if (newsk == NULL)
790                 goto exit;
791
792         sk_setup_caps(newsk, dst);
793
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;
801         ireq->opt          = NULL;
802         newinet->mc_index  = inet_iif(skb);
803         newinet->mc_ttl    = skb->nh.iph->ttl;
804         newinet->id        = jiffies;
805
806         dccp_sync_mss(newsk, dst_mtu(dst));
807
808         __inet_hash(&dccp_hashinfo, newsk, 0);
809         __inet_inherit_port(&dccp_hashinfo, sk, newsk);
810
811         return newsk;
812
813 exit_overflow:
814         NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
815 exit:
816         NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
817         dst_release(dst);
818         return NULL;
819 }
820
821 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
822 {
823         const struct dccp_hdr *dh = dccp_hdr(skb);
824         const struct iphdr *iph = skb->nh.iph;
825         struct sock *nsk;
826         struct request_sock **prev;
827         /* Find possible connection requests. */
828         struct request_sock *req = inet_csk_search_req(sk, &prev,
829                                                        dh->dccph_sport,
830                                                        iph->saddr, iph->daddr);
831         if (req != NULL)
832                 return dccp_check_req(sk, skb, req, prev);
833
834         nsk = __inet_lookup_established(&dccp_hashinfo,
835                                         iph->saddr, dh->dccph_sport,
836                                         iph->daddr, ntohs(dh->dccph_dport),
837                                         inet_iif(skb));
838         if (nsk != NULL) {
839                 if (nsk->sk_state != DCCP_TIME_WAIT) {
840                         bh_lock_sock(nsk);
841                         return nsk;
842                 }
843                 inet_twsk_put((struct inet_timewait_sock *)nsk);
844                 return NULL;
845         }
846
847         return sk;
848 }
849
850 int dccp_v4_checksum(const struct sk_buff *skb, const u32 saddr,
851                      const u32 daddr)
852 {
853         const struct dccp_hdr* dh = dccp_hdr(skb);
854         int checksum_len;
855         u32 tmp;
856
857         if (dh->dccph_cscov == 0)
858                 checksum_len = skb->len;
859         else {
860                 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
861                 checksum_len = checksum_len < skb->len ? checksum_len :
862                                                          skb->len;
863         }
864
865         tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
866         return csum_tcpudp_magic(saddr, daddr, checksum_len,
867                                  IPPROTO_DCCP, tmp);
868 }
869
870 static int dccp_v4_verify_checksum(struct sk_buff *skb,
871                                    const u32 saddr, const u32 daddr)
872 {
873         struct dccp_hdr *dh = dccp_hdr(skb);
874         int checksum_len;
875         u32 tmp;
876
877         if (dh->dccph_cscov == 0)
878                 checksum_len = skb->len;
879         else {
880                 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
881                 checksum_len = checksum_len < skb->len ? checksum_len :
882                                                          skb->len;
883         }
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;
887 }
888
889 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
890                                            struct sk_buff *skb)
891 {
892         struct rtable *rt;
893         struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
894                             .nl_u = { .ip4_u =
895                                       { .daddr = skb->nh.iph->saddr,
896                                         .saddr = skb->nh.iph->daddr,
897                                         .tos = RT_CONN_FLAGS(sk) } },
898                             .proto = sk->sk_protocol,
899                             .uli_u = { .ports =
900                                        { .sport = dccp_hdr(skb)->dccph_dport,
901                                          .dport = dccp_hdr(skb)->dccph_sport }
902                                      }
903                           };
904
905         if (ip_route_output_flow(&rt, &fl, sk, 0)) {
906                 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
907                 return NULL;
908         }
909
910         return &rt->u.dst;
911 }
912
913 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
914 {
915         int err;
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);
920         struct sk_buff *skb;
921         struct dst_entry *dst;
922         u64 seqno;
923
924         /* Never send a reset in response to a reset. */
925         if (rxdh->dccph_type == DCCP_PKT_RESET)
926                 return;
927
928         if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
929                 return;
930
931         dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
932         if (dst == NULL)
933                 return;
934
935         skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
936         if (skb == NULL)
937                 goto out;
938
939         /* Reserve space for headers. */
940         skb_reserve(skb, MAX_DCCP_HEADER);
941         skb->dst = dst_clone(dst);
942
943         skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
944         dh = dccp_hdr(skb);
945         memset(dh, 0, dccp_hdr_reset_len);
946
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;
952         dh->dccph_x        = 1;
953         dccp_hdr_reset(skb)->dccph_reset_code =
954                                 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
955
956         /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
957         seqno = 0;
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);
960
961         dccp_hdr_set_seq(dh, seqno);
962         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
963                          DCCP_SKB_CB(rxskb)->dccpd_seq);
964
965         dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
966                                               rxskb->nh.iph->daddr);
967
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);
973
974         if (err == NET_XMIT_CN || err == 0) {
975                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
976                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
977         }
978 out:
979          dst_release(dst);
980 }
981
982 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
983 {
984         struct dccp_hdr *dh = dccp_hdr(skb);
985
986         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
987                 if (dccp_rcv_established(sk, skb, dh, skb->len))
988                         goto reset;
989                 return 0;
990         }
991
992         /*
993          *  Step 3: Process LISTEN state
994          *     If S.state == LISTEN,
995          *        If P.type == Request or P contains a valid Init Cookie
996          *              option,
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
1001          *              Cookies *
1002          *           * Generate a new socket and switch to that socket *
1003          *           Set S := new socket for this port pair
1004          *           S.state = RESPOND
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 *
1009          *        Otherwise,
1010          *           Generate Reset(No Connection) unless P.type == Reset
1011          *           Drop packet and return
1012          *
1013          * NOTE: the check for the packet types is done in
1014          *       dccp_rcv_state_process
1015          */
1016         if (sk->sk_state == DCCP_LISTEN) {
1017                 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
1018
1019                 if (nsk == NULL)
1020                         goto discard;
1021
1022                 if (nsk != sk) {
1023                         if (dccp_child_process(sk, nsk, skb))
1024                                 goto reset;
1025                         return 0;
1026                 }
1027         }
1028
1029         if (dccp_rcv_state_process(sk, skb, dh, skb->len))
1030                 goto reset;
1031         return 0;
1032
1033 reset:
1034         dccp_v4_ctl_send_reset(skb);
1035 discard:
1036         kfree_skb(skb);
1037         return 0;
1038 }
1039
1040 static inline int dccp_invalid_packet(struct sk_buff *skb)
1041 {
1042         const struct dccp_hdr *dh;
1043
1044         if (skb->pkt_type != PACKET_HOST)
1045                 return 1;
1046
1047         if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
1048                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
1049                 return 1;
1050         }
1051
1052         dh = dccp_hdr(skb);
1053
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");
1057                 return 1;
1058         }
1059
1060         /*
1061          * If P.Data Offset is too small for packet type, or too large for
1062          * packet, drop packet and return
1063          */
1064         if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
1065                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1066                                             "too small 1\n",
1067                                dh->dccph_doff);
1068                 return 1;
1069         }
1070
1071         if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
1072                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1073                                             "too small 2\n",
1074                                dh->dccph_doff);
1075                 return 1;
1076         }
1077
1078         dh = dccp_hdr(skb);
1079
1080         /*
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
1083          */
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));
1091                 return 1;
1092         }
1093
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 "
1098                                             "incorrect\n");
1099                 return 1;
1100         }
1101
1102         return 0;
1103 }
1104
1105 /* this is called when real data arrives */
1106 int dccp_v4_rcv(struct sk_buff *skb)
1107 {
1108         const struct dccp_hdr *dh;
1109         struct sock *sk;
1110         int rc;
1111
1112         /* Step 1: Check header basics: */
1113
1114         if (dccp_invalid_packet(skb))
1115                 goto discard_it;
1116
1117         dh = dccp_hdr(skb);
1118
1119         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(skb);
1120         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
1121
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);
1129
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");
1133         } else {
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);
1138         }
1139
1140         /* Step 2:
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),
1145                            inet_iif(skb));
1146
1147         /* 
1148          * Step 2:
1149          *      If no socket ...
1150          *              Generate Reset(No Connection) unless P.type == Reset
1151          *              Drop packet and return
1152          */
1153         if (sk == NULL) {
1154                 dccp_pr_debug("failed to look up flow ID in table and "
1155                               "get corresponding socket\n");
1156                 goto no_dccp_socket;
1157         }
1158
1159         /* 
1160          * Step 2:
1161          *      ... or S.state == TIMEWAIT,
1162          *              Generate Reset(No Connection) unless P.type == Reset
1163          *              Drop packet and return
1164          */
1165                
1166         if (sk->sk_state == DCCP_TIME_WAIT) {
1167                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
1168                               "do_time_wait\n");
1169                 goto do_time_wait;
1170         }
1171
1172         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
1173                 dccp_pr_debug("xfrm4_policy_check failed\n");
1174                 goto discard_and_relse;
1175         }
1176
1177         if (sk_filter(sk, skb, 0)) {
1178                 dccp_pr_debug("sk_filter failed\n");
1179                 goto discard_and_relse;
1180         }
1181
1182         skb->dev = NULL;
1183
1184         bh_lock_sock(sk);
1185         rc = 0;
1186         if (!sock_owned_by_user(sk))
1187                 rc = dccp_v4_do_rcv(sk, skb);
1188         else
1189                 sk_add_backlog(sk, skb);
1190         bh_unlock_sock(sk);
1191
1192         sock_put(sk);
1193         return rc;
1194
1195 no_dccp_socket:
1196         if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1197                 goto discard_it;
1198         /*
1199          * Step 2:
1200          *              Generate Reset(No Connection) unless P.type == Reset
1201          *              Drop packet and return
1202          */
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);
1207         }
1208
1209 discard_it:
1210         /* Discard frame. */
1211         kfree_skb(skb);
1212         return 0;
1213
1214 discard_and_relse:
1215         sock_put(sk);
1216         goto discard_it;
1217
1218 do_time_wait:
1219         inet_twsk_put((struct inet_timewait_sock *)sk);
1220         goto no_dccp_socket;
1221 }
1222
1223 static int dccp_v4_init_sock(struct sock *sk)
1224 {
1225         struct dccp_sock *dp = dccp_sk(sk);
1226         static int dccp_ctl_socket_init = 1;
1227
1228         dccp_options_init(&dp->dccps_options);
1229         do_gettimeofday(&dp->dccps_epoch);
1230
1231         if (dp->dccps_options.dccpo_send_ack_vector) {
1232                 dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN,
1233                                                            GFP_KERNEL);
1234                 if (dp->dccps_hc_rx_ackvec == NULL)
1235                         return -ENOMEM;
1236         }
1237
1238         /*
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
1244          */
1245         if (likely(!dccp_ctl_socket_init)) {
1246                 dp->dccps_hc_rx_ccid = ccid_init(dp->dccps_options.dccpo_rx_ccid,
1247                                                  sk);
1248                 dp->dccps_hc_tx_ccid = ccid_init(dp->dccps_options.dccpo_tx_ccid,
1249                                                  sk);
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;
1257                         }
1258                         dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
1259                         return -ENOMEM;
1260                 }
1261         } else
1262                 dccp_ctl_socket_init = 0;
1263
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;
1271
1272         return 0;
1273 }
1274
1275 static int dccp_v4_destroy_sock(struct sock *sk)
1276 {
1277         struct dccp_sock *dp = dccp_sk(sk);
1278
1279         /*
1280          * DCCP doesn't use sk_qrite_queue, just sk_send_head
1281          * for retransmissions
1282          */
1283         if (sk->sk_send_head != NULL) {
1284                 kfree_skb(sk->sk_send_head);
1285                 sk->sk_send_head = NULL;
1286         }
1287
1288         /* Clean up a referenced DCCP bind bucket. */
1289         if (inet_csk(sk)->icsk_bind_hash != NULL)
1290                 inet_put_port(&dccp_hashinfo, sk);
1291
1292         if (dp->dccps_service_list != NULL) {
1293                 kfree(dp->dccps_service_list);
1294                 dp->dccps_service_list = NULL;
1295         }
1296
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;
1302         }
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;
1306
1307         return 0;
1308 }
1309
1310 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1311 {
1312         kfree(inet_rsk(req)->opt);
1313 }
1314
1315 static struct request_sock_ops dccp_request_sock_ops = {
1316         .family         = PF_INET,
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,
1322 };
1323
1324 struct proto dccp_v4_prot = {
1325         .name                   = "DCCP",
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),
1348 };