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TOMOYO Linux Cross Reference
Linux/net/dccp/ipv6.c

Version: ~ [ linux-5.12-rc7 ] ~ [ linux-5.11.13 ] ~ [ linux-5.10.29 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.111 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.186 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.230 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.266 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.266 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  *      DCCP over IPv6
  3  *      Linux INET6 implementation
  4  *
  5  *      Based on net/dccp6/ipv6.c
  6  *
  7  *      Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
  8  *
  9  *      This program is free software; you can redistribute it and/or
 10  *      modify it under the terms of the GNU General Public License
 11  *      as published by the Free Software Foundation; either version
 12  *      2 of the License, or (at your option) any later version.
 13  */
 14 
 15 #include <linux/module.h>
 16 #include <linux/random.h>
 17 #include <linux/slab.h>
 18 #include <linux/xfrm.h>
 19 
 20 #include <net/addrconf.h>
 21 #include <net/inet_common.h>
 22 #include <net/inet_hashtables.h>
 23 #include <net/inet_sock.h>
 24 #include <net/inet6_connection_sock.h>
 25 #include <net/inet6_hashtables.h>
 26 #include <net/ip6_route.h>
 27 #include <net/ipv6.h>
 28 #include <net/protocol.h>
 29 #include <net/transp_v6.h>
 30 #include <net/ip6_checksum.h>
 31 #include <net/xfrm.h>
 32 #include <net/secure_seq.h>
 33 
 34 #include "dccp.h"
 35 #include "ipv6.h"
 36 #include "feat.h"
 37 
 38 /* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */
 39 
 40 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
 41 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
 42 
 43 /* add pseudo-header to DCCP checksum stored in skb->csum */
 44 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
 45                                       const struct in6_addr *saddr,
 46                                       const struct in6_addr *daddr)
 47 {
 48         return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
 49 }
 50 
 51 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
 52 {
 53         struct ipv6_pinfo *np = inet6_sk(sk);
 54         struct dccp_hdr *dh = dccp_hdr(skb);
 55 
 56         dccp_csum_outgoing(skb);
 57         dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
 58 }
 59 
 60 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
 61 {
 62         return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 63                                              ipv6_hdr(skb)->saddr.s6_addr32,
 64                                              dccp_hdr(skb)->dccph_dport,
 65                                              dccp_hdr(skb)->dccph_sport     );
 66 
 67 }
 68 
 69 static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 70                         u8 type, u8 code, int offset, __be32 info)
 71 {
 72         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 73         const struct dccp_hdr *dh;
 74         struct dccp_sock *dp;
 75         struct ipv6_pinfo *np;
 76         struct sock *sk;
 77         int err;
 78         __u64 seq;
 79         struct net *net = dev_net(skb->dev);
 80 
 81         /* Only need dccph_dport & dccph_sport which are the first
 82          * 4 bytes in dccp header.
 83          * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
 84          */
 85         BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
 86         BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
 87         dh = (struct dccp_hdr *)(skb->data + offset);
 88 
 89         sk = __inet6_lookup_established(net, &dccp_hashinfo,
 90                                         &hdr->daddr, dh->dccph_dport,
 91                                         &hdr->saddr, ntohs(dh->dccph_sport),
 92                                         inet6_iif(skb));
 93 
 94         if (!sk) {
 95                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 96                                   ICMP6_MIB_INERRORS);
 97                 return;
 98         }
 99 
100         if (sk->sk_state == DCCP_TIME_WAIT) {
101                 inet_twsk_put(inet_twsk(sk));
102                 return;
103         }
104         seq = dccp_hdr_seq(dh);
105         if (sk->sk_state == DCCP_NEW_SYN_RECV)
106                 return dccp_req_err(sk, seq);
107 
108         bh_lock_sock(sk);
109         if (sock_owned_by_user(sk))
110                 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
111 
112         if (sk->sk_state == DCCP_CLOSED)
113                 goto out;
114 
115         dp = dccp_sk(sk);
116         if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
117             !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
118                 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
119                 goto out;
120         }
121 
122         np = inet6_sk(sk);
123 
124         if (type == NDISC_REDIRECT) {
125                 if (!sock_owned_by_user(sk)) {
126                         struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
127 
128                         if (dst)
129                                 dst->ops->redirect(dst, sk, skb);
130                 }
131                 goto out;
132         }
133 
134         if (type == ICMPV6_PKT_TOOBIG) {
135                 struct dst_entry *dst = NULL;
136 
137                 if (!ip6_sk_accept_pmtu(sk))
138                         goto out;
139 
140                 if (sock_owned_by_user(sk))
141                         goto out;
142                 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
143                         goto out;
144 
145                 dst = inet6_csk_update_pmtu(sk, ntohl(info));
146                 if (!dst)
147                         goto out;
148 
149                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
150                         dccp_sync_mss(sk, dst_mtu(dst));
151                 goto out;
152         }
153 
154         icmpv6_err_convert(type, code, &err);
155 
156         /* Might be for an request_sock */
157         switch (sk->sk_state) {
158         case DCCP_REQUESTING:
159         case DCCP_RESPOND:  /* Cannot happen.
160                                It can, it SYNs are crossed. --ANK */
161                 if (!sock_owned_by_user(sk)) {
162                         __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
163                         sk->sk_err = err;
164                         /*
165                          * Wake people up to see the error
166                          * (see connect in sock.c)
167                          */
168                         sk->sk_error_report(sk);
169                         dccp_done(sk);
170                 } else
171                         sk->sk_err_soft = err;
172                 goto out;
173         }
174 
175         if (!sock_owned_by_user(sk) && np->recverr) {
176                 sk->sk_err = err;
177                 sk->sk_error_report(sk);
178         } else
179                 sk->sk_err_soft = err;
180 
181 out:
182         bh_unlock_sock(sk);
183         sock_put(sk);
184 }
185 
186 
187 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
188 {
189         struct inet_request_sock *ireq = inet_rsk(req);
190         struct ipv6_pinfo *np = inet6_sk(sk);
191         struct sk_buff *skb;
192         struct in6_addr *final_p, final;
193         struct flowi6 fl6;
194         int err = -1;
195         struct dst_entry *dst;
196 
197         memset(&fl6, 0, sizeof(fl6));
198         fl6.flowi6_proto = IPPROTO_DCCP;
199         fl6.daddr = ireq->ir_v6_rmt_addr;
200         fl6.saddr = ireq->ir_v6_loc_addr;
201         fl6.flowlabel = 0;
202         fl6.flowi6_oif = ireq->ir_iif;
203         fl6.fl6_dport = ireq->ir_rmt_port;
204         fl6.fl6_sport = htons(ireq->ir_num);
205         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
206 
207 
208         rcu_read_lock();
209         final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
210         rcu_read_unlock();
211 
212         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
213         if (IS_ERR(dst)) {
214                 err = PTR_ERR(dst);
215                 dst = NULL;
216                 goto done;
217         }
218 
219         skb = dccp_make_response(sk, dst, req);
220         if (skb != NULL) {
221                 struct dccp_hdr *dh = dccp_hdr(skb);
222                 struct ipv6_txoptions *opt;
223 
224                 dh->dccph_checksum = dccp_v6_csum_finish(skb,
225                                                          &ireq->ir_v6_loc_addr,
226                                                          &ireq->ir_v6_rmt_addr);
227                 fl6.daddr = ireq->ir_v6_rmt_addr;
228                 rcu_read_lock();
229                 opt = ireq->ipv6_opt;
230                 if (!opt)
231                         opt = rcu_dereference(np->opt);
232                 err = ip6_xmit(sk, skb, &fl6, sk->sk_mark, opt, np->tclass);
233                 rcu_read_unlock();
234                 err = net_xmit_eval(err);
235         }
236 
237 done:
238         dst_release(dst);
239         return err;
240 }
241 
242 static void dccp_v6_reqsk_destructor(struct request_sock *req)
243 {
244         dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
245         kfree(inet_rsk(req)->ipv6_opt);
246         kfree_skb(inet_rsk(req)->pktopts);
247 }
248 
249 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
250 {
251         const struct ipv6hdr *rxip6h;
252         struct sk_buff *skb;
253         struct flowi6 fl6;
254         struct net *net = dev_net(skb_dst(rxskb)->dev);
255         struct sock *ctl_sk = net->dccp.v6_ctl_sk;
256         struct dst_entry *dst;
257 
258         if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
259                 return;
260 
261         if (!ipv6_unicast_destination(rxskb))
262                 return;
263 
264         skb = dccp_ctl_make_reset(ctl_sk, rxskb);
265         if (skb == NULL)
266                 return;
267 
268         rxip6h = ipv6_hdr(rxskb);
269         dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
270                                                             &rxip6h->daddr);
271 
272         memset(&fl6, 0, sizeof(fl6));
273         fl6.daddr = rxip6h->saddr;
274         fl6.saddr = rxip6h->daddr;
275 
276         fl6.flowi6_proto = IPPROTO_DCCP;
277         fl6.flowi6_oif = inet6_iif(rxskb);
278         fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
279         fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
280         security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
281 
282         /* sk = NULL, but it is safe for now. RST socket required. */
283         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
284         if (!IS_ERR(dst)) {
285                 skb_dst_set(skb, dst);
286                 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0);
287                 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
288                 DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
289                 return;
290         }
291 
292         kfree_skb(skb);
293 }
294 
295 static struct request_sock_ops dccp6_request_sock_ops = {
296         .family         = AF_INET6,
297         .obj_size       = sizeof(struct dccp6_request_sock),
298         .rtx_syn_ack    = dccp_v6_send_response,
299         .send_ack       = dccp_reqsk_send_ack,
300         .destructor     = dccp_v6_reqsk_destructor,
301         .send_reset     = dccp_v6_ctl_send_reset,
302         .syn_ack_timeout = dccp_syn_ack_timeout,
303 };
304 
305 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
306 {
307         struct request_sock *req;
308         struct dccp_request_sock *dreq;
309         struct inet_request_sock *ireq;
310         struct ipv6_pinfo *np = inet6_sk(sk);
311         const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
312         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
313 
314         if (skb->protocol == htons(ETH_P_IP))
315                 return dccp_v4_conn_request(sk, skb);
316 
317         if (!ipv6_unicast_destination(skb))
318                 return 0;       /* discard, don't send a reset here */
319 
320         if (dccp_bad_service_code(sk, service)) {
321                 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
322                 goto drop;
323         }
324         /*
325          * There are no SYN attacks on IPv6, yet...
326          */
327         dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
328         if (inet_csk_reqsk_queue_is_full(sk))
329                 goto drop;
330 
331         if (sk_acceptq_is_full(sk))
332                 goto drop;
333 
334         req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
335         if (req == NULL)
336                 goto drop;
337 
338         if (dccp_reqsk_init(req, dccp_sk(sk), skb))
339                 goto drop_and_free;
340 
341         dreq = dccp_rsk(req);
342         if (dccp_parse_options(sk, dreq, skb))
343                 goto drop_and_free;
344 
345         if (security_inet_conn_request(sk, skb, req))
346                 goto drop_and_free;
347 
348         ireq = inet_rsk(req);
349         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
350         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
351         ireq->ireq_family = AF_INET6;
352 
353         if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
354             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
355             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
356                 atomic_inc(&skb->users);
357                 ireq->pktopts = skb;
358         }
359         ireq->ir_iif = sk->sk_bound_dev_if;
360 
361         /* So that link locals have meaning */
362         if (!sk->sk_bound_dev_if &&
363             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
364                 ireq->ir_iif = inet6_iif(skb);
365 
366         /*
367          * Step 3: Process LISTEN state
368          *
369          *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
370          *
371          * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
372          */
373         dreq->dreq_isr     = dcb->dccpd_seq;
374         dreq->dreq_gsr     = dreq->dreq_isr;
375         dreq->dreq_iss     = dccp_v6_init_sequence(skb);
376         dreq->dreq_gss     = dreq->dreq_iss;
377         dreq->dreq_service = service;
378 
379         if (dccp_v6_send_response(sk, req))
380                 goto drop_and_free;
381 
382         inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
383         return 0;
384 
385 drop_and_free:
386         reqsk_free(req);
387 drop:
388         __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
389         return -1;
390 }
391 
392 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
393                                               struct sk_buff *skb,
394                                               struct request_sock *req,
395                                               struct dst_entry *dst,
396                                               struct request_sock *req_unhash,
397                                               bool *own_req)
398 {
399         struct inet_request_sock *ireq = inet_rsk(req);
400         struct ipv6_pinfo *newnp;
401         const struct ipv6_pinfo *np = inet6_sk(sk);
402         struct ipv6_txoptions *opt;
403         struct inet_sock *newinet;
404         struct dccp6_sock *newdp6;
405         struct sock *newsk;
406 
407         if (skb->protocol == htons(ETH_P_IP)) {
408                 /*
409                  *      v6 mapped
410                  */
411                 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
412                                                   req_unhash, own_req);
413                 if (newsk == NULL)
414                         return NULL;
415 
416                 newdp6 = (struct dccp6_sock *)newsk;
417                 newinet = inet_sk(newsk);
418                 newinet->pinet6 = &newdp6->inet6;
419                 newnp = inet6_sk(newsk);
420 
421                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
422 
423                 newnp->saddr = newsk->sk_v6_rcv_saddr;
424 
425                 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
426                 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
427                 newnp->pktoptions  = NULL;
428                 newnp->opt         = NULL;
429                 newnp->ipv6_mc_list = NULL;
430                 newnp->ipv6_ac_list = NULL;
431                 newnp->ipv6_fl_list = NULL;
432                 newnp->mcast_oif   = inet6_iif(skb);
433                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
434 
435                 /*
436                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
437                  * here, dccp_create_openreq_child now does this for us, see the comment in
438                  * that function for the gory details. -acme
439                  */
440 
441                 /* It is tricky place. Until this moment IPv4 tcp
442                    worked with IPv6 icsk.icsk_af_ops.
443                    Sync it now.
444                  */
445                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
446 
447                 return newsk;
448         }
449 
450 
451         if (sk_acceptq_is_full(sk))
452                 goto out_overflow;
453 
454         if (!dst) {
455                 struct flowi6 fl6;
456 
457                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
458                 if (!dst)
459                         goto out;
460         }
461 
462         newsk = dccp_create_openreq_child(sk, req, skb);
463         if (newsk == NULL)
464                 goto out_nonewsk;
465 
466         /*
467          * No need to charge this sock to the relevant IPv6 refcnt debug socks
468          * count here, dccp_create_openreq_child now does this for us, see the
469          * comment in that function for the gory details. -acme
470          */
471 
472         ip6_dst_store(newsk, dst, NULL, NULL);
473         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
474                                                       NETIF_F_TSO);
475         newdp6 = (struct dccp6_sock *)newsk;
476         newinet = inet_sk(newsk);
477         newinet->pinet6 = &newdp6->inet6;
478         newnp = inet6_sk(newsk);
479 
480         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
481 
482         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
483         newnp->saddr            = ireq->ir_v6_loc_addr;
484         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
485         newsk->sk_bound_dev_if  = ireq->ir_iif;
486 
487         /* Now IPv6 options...
488 
489            First: no IPv4 options.
490          */
491         newinet->inet_opt = NULL;
492 
493         /* Clone RX bits */
494         newnp->rxopt.all = np->rxopt.all;
495 
496         newnp->ipv6_mc_list = NULL;
497         newnp->ipv6_ac_list = NULL;
498         newnp->ipv6_fl_list = NULL;
499         newnp->pktoptions = NULL;
500         newnp->opt        = NULL;
501         newnp->mcast_oif  = inet6_iif(skb);
502         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
503 
504         /*
505          * Clone native IPv6 options from listening socket (if any)
506          *
507          * Yes, keeping reference count would be much more clever, but we make
508          * one more one thing there: reattach optmem to newsk.
509          */
510         opt = ireq->ipv6_opt;
511         if (!opt)
512                 opt = rcu_dereference(np->opt);
513         if (opt) {
514                 opt = ipv6_dup_options(newsk, opt);
515                 RCU_INIT_POINTER(newnp->opt, opt);
516         }
517         inet_csk(newsk)->icsk_ext_hdr_len = 0;
518         if (opt)
519                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
520                                                     opt->opt_flen;
521 
522         dccp_sync_mss(newsk, dst_mtu(dst));
523 
524         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
525         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
526 
527         if (__inet_inherit_port(sk, newsk) < 0) {
528                 inet_csk_prepare_forced_close(newsk);
529                 dccp_done(newsk);
530                 goto out;
531         }
532         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
533         /* Clone pktoptions received with SYN, if we own the req */
534         if (*own_req && ireq->pktopts) {
535                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
536                 consume_skb(ireq->pktopts);
537                 ireq->pktopts = NULL;
538                 if (newnp->pktoptions)
539                         skb_set_owner_r(newnp->pktoptions, newsk);
540         }
541 
542         return newsk;
543 
544 out_overflow:
545         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
546 out_nonewsk:
547         dst_release(dst);
548 out:
549         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
550         return NULL;
551 }
552 
553 /* The socket must have it's spinlock held when we get
554  * here.
555  *
556  * We have a potential double-lock case here, so even when
557  * doing backlog processing we use the BH locking scheme.
558  * This is because we cannot sleep with the original spinlock
559  * held.
560  */
561 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
562 {
563         struct ipv6_pinfo *np = inet6_sk(sk);
564         struct sk_buff *opt_skb = NULL;
565 
566         /* Imagine: socket is IPv6. IPv4 packet arrives,
567            goes to IPv4 receive handler and backlogged.
568            From backlog it always goes here. Kerboom...
569            Fortunately, dccp_rcv_established and rcv_established
570            handle them correctly, but it is not case with
571            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
572          */
573 
574         if (skb->protocol == htons(ETH_P_IP))
575                 return dccp_v4_do_rcv(sk, skb);
576 
577         if (sk_filter(sk, skb))
578                 goto discard;
579 
580         /*
581          * socket locking is here for SMP purposes as backlog rcv is currently
582          * called with bh processing disabled.
583          */
584 
585         /* Do Stevens' IPV6_PKTOPTIONS.
586 
587            Yes, guys, it is the only place in our code, where we
588            may make it not affecting IPv4.
589            The rest of code is protocol independent,
590            and I do not like idea to uglify IPv4.
591 
592            Actually, all the idea behind IPV6_PKTOPTIONS
593            looks not very well thought. For now we latch
594            options, received in the last packet, enqueued
595            by tcp. Feel free to propose better solution.
596                                                --ANK (980728)
597          */
598         if (np->rxopt.all)
599         /*
600          * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
601          *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
602          */
603                 opt_skb = skb_clone(skb, GFP_ATOMIC);
604 
605         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
606                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
607                         goto reset;
608                 if (opt_skb) {
609                         /* XXX This is where we would goto ipv6_pktoptions. */
610                         __kfree_skb(opt_skb);
611                 }
612                 return 0;
613         }
614 
615         /*
616          *  Step 3: Process LISTEN state
617          *     If S.state == LISTEN,
618          *       If P.type == Request or P contains a valid Init Cookie option,
619          *            (* Must scan the packet's options to check for Init
620          *               Cookies.  Only Init Cookies are processed here,
621          *               however; other options are processed in Step 8.  This
622          *               scan need only be performed if the endpoint uses Init
623          *               Cookies *)
624          *            (* Generate a new socket and switch to that socket *)
625          *            Set S := new socket for this port pair
626          *            S.state = RESPOND
627          *            Choose S.ISS (initial seqno) or set from Init Cookies
628          *            Initialize S.GAR := S.ISS
629          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
630          *            Continue with S.state == RESPOND
631          *            (* A Response packet will be generated in Step 11 *)
632          *       Otherwise,
633          *            Generate Reset(No Connection) unless P.type == Reset
634          *            Drop packet and return
635          *
636          * NOTE: the check for the packet types is done in
637          *       dccp_rcv_state_process
638          */
639 
640         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
641                 goto reset;
642         if (opt_skb) {
643                 /* XXX This is where we would goto ipv6_pktoptions. */
644                 __kfree_skb(opt_skb);
645         }
646         return 0;
647 
648 reset:
649         dccp_v6_ctl_send_reset(sk, skb);
650 discard:
651         if (opt_skb != NULL)
652                 __kfree_skb(opt_skb);
653         kfree_skb(skb);
654         return 0;
655 }
656 
657 static int dccp_v6_rcv(struct sk_buff *skb)
658 {
659         const struct dccp_hdr *dh;
660         bool refcounted;
661         struct sock *sk;
662         int min_cov;
663 
664         /* Step 1: Check header basics */
665 
666         if (dccp_invalid_packet(skb))
667                 goto discard_it;
668 
669         /* Step 1: If header checksum is incorrect, drop packet and return. */
670         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
671                                      &ipv6_hdr(skb)->daddr)) {
672                 DCCP_WARN("dropped packet with invalid checksum\n");
673                 goto discard_it;
674         }
675 
676         dh = dccp_hdr(skb);
677 
678         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
679         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
680 
681         if (dccp_packet_without_ack(skb))
682                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
683         else
684                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
685 
686 lookup:
687         sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
688                                 dh->dccph_sport, dh->dccph_dport,
689                                 inet6_iif(skb), &refcounted);
690         if (!sk) {
691                 dccp_pr_debug("failed to look up flow ID in table and "
692                               "get corresponding socket\n");
693                 goto no_dccp_socket;
694         }
695 
696         /*
697          * Step 2:
698          *      ... or S.state == TIMEWAIT,
699          *              Generate Reset(No Connection) unless P.type == Reset
700          *              Drop packet and return
701          */
702         if (sk->sk_state == DCCP_TIME_WAIT) {
703                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
704                 inet_twsk_put(inet_twsk(sk));
705                 goto no_dccp_socket;
706         }
707 
708         if (sk->sk_state == DCCP_NEW_SYN_RECV) {
709                 struct request_sock *req = inet_reqsk(sk);
710                 struct sock *nsk;
711 
712                 sk = req->rsk_listener;
713                 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
714                         inet_csk_reqsk_queue_drop_and_put(sk, req);
715                         goto lookup;
716                 }
717                 sock_hold(sk);
718                 refcounted = true;
719                 nsk = dccp_check_req(sk, skb, req);
720                 if (!nsk) {
721                         reqsk_put(req);
722                         goto discard_and_relse;
723                 }
724                 if (nsk == sk) {
725                         reqsk_put(req);
726                 } else if (dccp_child_process(sk, nsk, skb)) {
727                         dccp_v6_ctl_send_reset(sk, skb);
728                         goto discard_and_relse;
729                 } else {
730                         sock_put(sk);
731                         return 0;
732                 }
733         }
734         /*
735          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
736          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
737          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
738          */
739         min_cov = dccp_sk(sk)->dccps_pcrlen;
740         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
741                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
742                               dh->dccph_cscov, min_cov);
743                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
744                 goto discard_and_relse;
745         }
746 
747         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
748                 goto discard_and_relse;
749 
750         return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4,
751                                 refcounted) ? -1 : 0;
752 
753 no_dccp_socket:
754         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
755                 goto discard_it;
756         /*
757          * Step 2:
758          *      If no socket ...
759          *              Generate Reset(No Connection) unless P.type == Reset
760          *              Drop packet and return
761          */
762         if (dh->dccph_type != DCCP_PKT_RESET) {
763                 DCCP_SKB_CB(skb)->dccpd_reset_code =
764                                         DCCP_RESET_CODE_NO_CONNECTION;
765                 dccp_v6_ctl_send_reset(sk, skb);
766         }
767 
768 discard_it:
769         kfree_skb(skb);
770         return 0;
771 
772 discard_and_relse:
773         if (refcounted)
774                 sock_put(sk);
775         goto discard_it;
776 }
777 
778 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
779                            int addr_len)
780 {
781         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
782         struct inet_connection_sock *icsk = inet_csk(sk);
783         struct inet_sock *inet = inet_sk(sk);
784         struct ipv6_pinfo *np = inet6_sk(sk);
785         struct dccp_sock *dp = dccp_sk(sk);
786         struct in6_addr *saddr = NULL, *final_p, final;
787         struct ipv6_txoptions *opt;
788         struct flowi6 fl6;
789         struct dst_entry *dst;
790         int addr_type;
791         int err;
792 
793         dp->dccps_role = DCCP_ROLE_CLIENT;
794 
795         if (addr_len < SIN6_LEN_RFC2133)
796                 return -EINVAL;
797 
798         if (usin->sin6_family != AF_INET6)
799                 return -EAFNOSUPPORT;
800 
801         memset(&fl6, 0, sizeof(fl6));
802 
803         if (np->sndflow) {
804                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
805                 IP6_ECN_flow_init(fl6.flowlabel);
806                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
807                         struct ip6_flowlabel *flowlabel;
808                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
809                         if (flowlabel == NULL)
810                                 return -EINVAL;
811                         fl6_sock_release(flowlabel);
812                 }
813         }
814         /*
815          * connect() to INADDR_ANY means loopback (BSD'ism).
816          */
817         if (ipv6_addr_any(&usin->sin6_addr))
818                 usin->sin6_addr.s6_addr[15] = 1;
819 
820         addr_type = ipv6_addr_type(&usin->sin6_addr);
821 
822         if (addr_type & IPV6_ADDR_MULTICAST)
823                 return -ENETUNREACH;
824 
825         if (addr_type & IPV6_ADDR_LINKLOCAL) {
826                 if (addr_len >= sizeof(struct sockaddr_in6) &&
827                     usin->sin6_scope_id) {
828                         /* If interface is set while binding, indices
829                          * must coincide.
830                          */
831                         if (sk->sk_bound_dev_if &&
832                             sk->sk_bound_dev_if != usin->sin6_scope_id)
833                                 return -EINVAL;
834 
835                         sk->sk_bound_dev_if = usin->sin6_scope_id;
836                 }
837 
838                 /* Connect to link-local address requires an interface */
839                 if (!sk->sk_bound_dev_if)
840                         return -EINVAL;
841         }
842 
843         sk->sk_v6_daddr = usin->sin6_addr;
844         np->flow_label = fl6.flowlabel;
845 
846         /*
847          * DCCP over IPv4
848          */
849         if (addr_type == IPV6_ADDR_MAPPED) {
850                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
851                 struct sockaddr_in sin;
852 
853                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
854 
855                 if (__ipv6_only_sock(sk))
856                         return -ENETUNREACH;
857 
858                 sin.sin_family = AF_INET;
859                 sin.sin_port = usin->sin6_port;
860                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
861 
862                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
863                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
864 
865                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
866                 if (err) {
867                         icsk->icsk_ext_hdr_len = exthdrlen;
868                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
869                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
870                         goto failure;
871                 }
872                 np->saddr = sk->sk_v6_rcv_saddr;
873                 return err;
874         }
875 
876         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
877                 saddr = &sk->sk_v6_rcv_saddr;
878 
879         fl6.flowi6_proto = IPPROTO_DCCP;
880         fl6.daddr = sk->sk_v6_daddr;
881         fl6.saddr = saddr ? *saddr : np->saddr;
882         fl6.flowi6_oif = sk->sk_bound_dev_if;
883         fl6.fl6_dport = usin->sin6_port;
884         fl6.fl6_sport = inet->inet_sport;
885         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
886 
887         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
888         final_p = fl6_update_dst(&fl6, opt, &final);
889 
890         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
891         if (IS_ERR(dst)) {
892                 err = PTR_ERR(dst);
893                 goto failure;
894         }
895 
896         if (saddr == NULL) {
897                 saddr = &fl6.saddr;
898                 sk->sk_v6_rcv_saddr = *saddr;
899         }
900 
901         /* set the source address */
902         np->saddr = *saddr;
903         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
904 
905         ip6_dst_store(sk, dst, NULL, NULL);
906 
907         icsk->icsk_ext_hdr_len = 0;
908         if (opt)
909                 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
910 
911         inet->inet_dport = usin->sin6_port;
912 
913         dccp_set_state(sk, DCCP_REQUESTING);
914         err = inet6_hash_connect(&dccp_death_row, sk);
915         if (err)
916                 goto late_failure;
917 
918         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
919                                                       sk->sk_v6_daddr.s6_addr32,
920                                                       inet->inet_sport,
921                                                       inet->inet_dport);
922         err = dccp_connect(sk);
923         if (err)
924                 goto late_failure;
925 
926         return 0;
927 
928 late_failure:
929         dccp_set_state(sk, DCCP_CLOSED);
930         __sk_dst_reset(sk);
931 failure:
932         inet->inet_dport = 0;
933         sk->sk_route_caps = 0;
934         return err;
935 }
936 
937 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
938         .queue_xmit        = inet6_csk_xmit,
939         .send_check        = dccp_v6_send_check,
940         .rebuild_header    = inet6_sk_rebuild_header,
941         .conn_request      = dccp_v6_conn_request,
942         .syn_recv_sock     = dccp_v6_request_recv_sock,
943         .net_header_len    = sizeof(struct ipv6hdr),
944         .setsockopt        = ipv6_setsockopt,
945         .getsockopt        = ipv6_getsockopt,
946         .addr2sockaddr     = inet6_csk_addr2sockaddr,
947         .sockaddr_len      = sizeof(struct sockaddr_in6),
948 #ifdef CONFIG_COMPAT
949         .compat_setsockopt = compat_ipv6_setsockopt,
950         .compat_getsockopt = compat_ipv6_getsockopt,
951 #endif
952 };
953 
954 /*
955  *      DCCP over IPv4 via INET6 API
956  */
957 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
958         .queue_xmit        = ip_queue_xmit,
959         .send_check        = dccp_v4_send_check,
960         .rebuild_header    = inet_sk_rebuild_header,
961         .conn_request      = dccp_v6_conn_request,
962         .syn_recv_sock     = dccp_v6_request_recv_sock,
963         .net_header_len    = sizeof(struct iphdr),
964         .setsockopt        = ipv6_setsockopt,
965         .getsockopt        = ipv6_getsockopt,
966         .addr2sockaddr     = inet6_csk_addr2sockaddr,
967         .sockaddr_len      = sizeof(struct sockaddr_in6),
968 #ifdef CONFIG_COMPAT
969         .compat_setsockopt = compat_ipv6_setsockopt,
970         .compat_getsockopt = compat_ipv6_getsockopt,
971 #endif
972 };
973 
974 /* NOTE: A lot of things set to zero explicitly by call to
975  *       sk_alloc() so need not be done here.
976  */
977 static int dccp_v6_init_sock(struct sock *sk)
978 {
979         static __u8 dccp_v6_ctl_sock_initialized;
980         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
981 
982         if (err == 0) {
983                 if (unlikely(!dccp_v6_ctl_sock_initialized))
984                         dccp_v6_ctl_sock_initialized = 1;
985                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
986         }
987 
988         return err;
989 }
990 
991 static void dccp_v6_destroy_sock(struct sock *sk)
992 {
993         dccp_destroy_sock(sk);
994         inet6_destroy_sock(sk);
995 }
996 
997 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
998         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
999 };
1000 
1001 static struct proto dccp_v6_prot = {
1002         .name              = "DCCPv6",
1003         .owner             = THIS_MODULE,
1004         .close             = dccp_close,
1005         .connect           = dccp_v6_connect,
1006         .disconnect        = dccp_disconnect,
1007         .ioctl             = dccp_ioctl,
1008         .init              = dccp_v6_init_sock,
1009         .setsockopt        = dccp_setsockopt,
1010         .getsockopt        = dccp_getsockopt,
1011         .sendmsg           = dccp_sendmsg,
1012         .recvmsg           = dccp_recvmsg,
1013         .backlog_rcv       = dccp_v6_do_rcv,
1014         .hash              = inet6_hash,
1015         .unhash            = inet_unhash,
1016         .accept            = inet_csk_accept,
1017         .get_port          = inet_csk_get_port,
1018         .shutdown          = dccp_shutdown,
1019         .destroy           = dccp_v6_destroy_sock,
1020         .orphan_count      = &dccp_orphan_count,
1021         .max_header        = MAX_DCCP_HEADER,
1022         .obj_size          = sizeof(struct dccp6_sock),
1023         .slab_flags        = SLAB_DESTROY_BY_RCU,
1024         .rsk_prot          = &dccp6_request_sock_ops,
1025         .twsk_prot         = &dccp6_timewait_sock_ops,
1026         .h.hashinfo        = &dccp_hashinfo,
1027 #ifdef CONFIG_COMPAT
1028         .compat_setsockopt = compat_dccp_setsockopt,
1029         .compat_getsockopt = compat_dccp_getsockopt,
1030 #endif
1031 };
1032 
1033 static const struct inet6_protocol dccp_v6_protocol = {
1034         .handler        = dccp_v6_rcv,
1035         .err_handler    = dccp_v6_err,
1036         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1037 };
1038 
1039 static const struct proto_ops inet6_dccp_ops = {
1040         .family            = PF_INET6,
1041         .owner             = THIS_MODULE,
1042         .release           = inet6_release,
1043         .bind              = inet6_bind,
1044         .connect           = inet_stream_connect,
1045         .socketpair        = sock_no_socketpair,
1046         .accept            = inet_accept,
1047         .getname           = inet6_getname,
1048         .poll              = dccp_poll,
1049         .ioctl             = inet6_ioctl,
1050         .listen            = inet_dccp_listen,
1051         .shutdown          = inet_shutdown,
1052         .setsockopt        = sock_common_setsockopt,
1053         .getsockopt        = sock_common_getsockopt,
1054         .sendmsg           = inet_sendmsg,
1055         .recvmsg           = sock_common_recvmsg,
1056         .mmap              = sock_no_mmap,
1057         .sendpage          = sock_no_sendpage,
1058 #ifdef CONFIG_COMPAT
1059         .compat_setsockopt = compat_sock_common_setsockopt,
1060         .compat_getsockopt = compat_sock_common_getsockopt,
1061 #endif
1062 };
1063 
1064 static struct inet_protosw dccp_v6_protosw = {
1065         .type           = SOCK_DCCP,
1066         .protocol       = IPPROTO_DCCP,
1067         .prot           = &dccp_v6_prot,
1068         .ops            = &inet6_dccp_ops,
1069         .flags          = INET_PROTOSW_ICSK,
1070 };
1071 
1072 static int __net_init dccp_v6_init_net(struct net *net)
1073 {
1074         if (dccp_hashinfo.bhash == NULL)
1075                 return -ESOCKTNOSUPPORT;
1076 
1077         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1078                                     SOCK_DCCP, IPPROTO_DCCP, net);
1079 }
1080 
1081 static void __net_exit dccp_v6_exit_net(struct net *net)
1082 {
1083         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1084 }
1085 
1086 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
1087 {
1088         inet_twsk_purge(&dccp_hashinfo, AF_INET6);
1089 }
1090 
1091 static struct pernet_operations dccp_v6_ops = {
1092         .init   = dccp_v6_init_net,
1093         .exit   = dccp_v6_exit_net,
1094         .exit_batch = dccp_v6_exit_batch,
1095 };
1096 
1097 static int __init dccp_v6_init(void)
1098 {
1099         int err = proto_register(&dccp_v6_prot, 1);
1100 
1101         if (err != 0)
1102                 goto out;
1103 
1104         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1105         if (err != 0)
1106                 goto out_unregister_proto;
1107 
1108         inet6_register_protosw(&dccp_v6_protosw);
1109 
1110         err = register_pernet_subsys(&dccp_v6_ops);
1111         if (err != 0)
1112                 goto out_destroy_ctl_sock;
1113 out:
1114         return err;
1115 
1116 out_destroy_ctl_sock:
1117         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1118         inet6_unregister_protosw(&dccp_v6_protosw);
1119 out_unregister_proto:
1120         proto_unregister(&dccp_v6_prot);
1121         goto out;
1122 }
1123 
1124 static void __exit dccp_v6_exit(void)
1125 {
1126         unregister_pernet_subsys(&dccp_v6_ops);
1127         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1128         inet6_unregister_protosw(&dccp_v6_protosw);
1129         proto_unregister(&dccp_v6_prot);
1130 }
1131 
1132 module_init(dccp_v6_init);
1133 module_exit(dccp_v6_exit);
1134 
1135 /*
1136  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1137  * values directly, Also cover the case where the protocol is not specified,
1138  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1139  */
1140 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1141 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1142 MODULE_LICENSE("GPL");
1143 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1144 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");
1145 

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