net/dccp/ipv6.c

   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 = (struct dccp_hdr *)(skb->data + offset);
  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         if (skb->len < offset + sizeof(*dh) ||
  82             skb->len < offset + __dccp_basic_hdr_len(dh)) {
  83                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
  84                                   ICMP6_MIB_INERRORS);
  85                 return;
  86         }
  87
  88         sk = __inet6_lookup_established(net, &dccp_hashinfo,
  89                                         &hdr->daddr, dh->dccph_dport,
  90                                         &hdr->saddr, ntohs(dh->dccph_sport),
  91                                         inet6_iif(skb));
  92
  93         if (!sk) {
  94                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
  95                                   ICMP6_MIB_INERRORS);
  96                 return;
  97         }
  98
  99         if (sk->sk_state == DCCP_TIME_WAIT) {
 100                 inet_twsk_put(inet_twsk(sk));
 101                 return;
 102         }
 103         seq = dccp_hdr_seq(dh);
 104         if (sk->sk_state == DCCP_NEW_SYN_RECV)
 105                 return dccp_req_err(sk, seq);
 106
 107         bh_lock_sock(sk);
 108         if (sock_owned_by_user(sk))
 109                 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
 110
 111         if (sk->sk_state == DCCP_CLOSED)
 112                 goto out;
 113
 114         dp = dccp_sk(sk);
 115         if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
 116             !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
 117                 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
 118                 goto out;
 119         }
 120
 121         np = inet6_sk(sk);
 122
 123         if (type == NDISC_REDIRECT) {
 124                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 125
 126                 if (dst)
 127                         dst->ops->redirect(dst, sk, skb);
 128                 goto out;
 129         }
 130
 131         if (type == ICMPV6_PKT_TOOBIG) {
 132                 struct dst_entry *dst = NULL;
 133
 134                 if (!ip6_sk_accept_pmtu(sk))
 135                         goto out;
 136
 137                 if (sock_owned_by_user(sk))
 138                         goto out;
 139                 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
 140                         goto out;
 141
 142                 dst = inet6_csk_update_pmtu(sk, ntohl(info));
 143                 if (!dst)
 144                         goto out;
 145
 146                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
 147                         dccp_sync_mss(sk, dst_mtu(dst));
 148                 goto out;
 149         }
 150
 151         icmpv6_err_convert(type, code, &err);
 152
 153         /* Might be for an request_sock */
 154         switch (sk->sk_state) {
 155         case DCCP_REQUESTING:
 156         case DCCP_RESPOND:  /* Cannot happen.
 157                                It can, it SYNs are crossed. --ANK */
 158                 if (!sock_owned_by_user(sk)) {
 159                         __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
 160                         sk->sk_err = err;
 161                         /*
 162                          * Wake people up to see the error
 163                          * (see connect in sock.c)
 164                          */
 165                         sk->sk_error_report(sk);
 166                         dccp_done(sk);
 167                 } else
 168                         sk->sk_err_soft = err;
 169                 goto out;
 170         }
 171
 172         if (!sock_owned_by_user(sk) && np->recverr) {
 173                 sk->sk_err = err;
 174                 sk->sk_error_report(sk);
 175         } else
 176                 sk->sk_err_soft = err;
 177
 178 out:
 179         bh_unlock_sock(sk);
 180         sock_put(sk);
 181 }
 182
 183
 184 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
 185 {
 186         struct inet_request_sock *ireq = inet_rsk(req);
 187         struct ipv6_pinfo *np = inet6_sk(sk);
 188         struct sk_buff *skb;
 189         struct in6_addr *final_p, final;
 190         struct flowi6 fl6;
 191         int err = -1;
 192         struct dst_entry *dst;
 193
 194         memset(&fl6, 0, sizeof(fl6));
 195         fl6.flowi6_proto = IPPROTO_DCCP;
 196         fl6.daddr = ireq->ir_v6_rmt_addr;
 197         fl6.saddr = ireq->ir_v6_loc_addr;
 198         fl6.flowlabel = 0;
 199         fl6.flowi6_oif = ireq->ir_iif;
 200         fl6.fl6_dport = ireq->ir_rmt_port;
 201         fl6.fl6_sport = htons(ireq->ir_num);
 202         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 203
 204
 205         rcu_read_lock();
 206         final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
 207         rcu_read_unlock();
 208
 209         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 210         if (IS_ERR(dst)) {
 211                 err = PTR_ERR(dst);
 212                 dst = NULL;
 213                 goto done;
 214         }
 215
 216         skb = dccp_make_response(sk, dst, req);
 217         if (skb != NULL) {
 218                 struct dccp_hdr *dh = dccp_hdr(skb);
 219                 struct ipv6_txoptions *opt;
 220
 221                 dh->dccph_checksum = dccp_v6_csum_finish(skb,
 222                                                          &ireq->ir_v6_loc_addr,
 223                                                          &ireq->ir_v6_rmt_addr);
 224                 fl6.daddr = ireq->ir_v6_rmt_addr;
 225                 rcu_read_lock();
 226                 opt = ireq->ipv6_opt;
 227                 if (!opt)
 228                         opt = rcu_dereference(np->opt);
 229                 err = ip6_xmit(sk, skb, &fl6, opt, np->tclass);
 230                 rcu_read_unlock();
 231                 err = net_xmit_eval(err);
 232         }
 233
 234 done:
 235         dst_release(dst);
 236         return err;
 237 }
 238
 239 static void dccp_v6_reqsk_destructor(struct request_sock *req)
 240 {
 241         dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
 242         kfree(inet_rsk(req)->ipv6_opt);
 243         kfree_skb(inet_rsk(req)->pktopts);
 244 }
 245
 246 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
 247 {
 248         const struct ipv6hdr *rxip6h;
 249         struct sk_buff *skb;
 250         struct flowi6 fl6;
 251         struct net *net = dev_net(skb_dst(rxskb)->dev);
 252         struct sock *ctl_sk = net->dccp.v6_ctl_sk;
 253         struct dst_entry *dst;
 254
 255         if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
 256                 return;
 257
 258         if (!ipv6_unicast_destination(rxskb))
 259                 return;
 260
 261         skb = dccp_ctl_make_reset(ctl_sk, rxskb);
 262         if (skb == NULL)
 263                 return;
 264
 265         rxip6h = ipv6_hdr(rxskb);
 266         dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
 267                                                             &rxip6h->daddr);
 268
 269         memset(&fl6, 0, sizeof(fl6));
 270         fl6.daddr = rxip6h->saddr;
 271         fl6.saddr = rxip6h->daddr;
 272
 273         fl6.flowi6_proto = IPPROTO_DCCP;
 274         fl6.flowi6_oif = inet6_iif(rxskb);
 275         fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
 276         fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
 277         security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
 278
 279         /* sk = NULL, but it is safe for now. RST socket required. */
 280         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 281         if (!IS_ERR(dst)) {
 282                 skb_dst_set(skb, dst);
 283                 ip6_xmit(ctl_sk, skb, &fl6, NULL, 0);
 284                 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
 285                 DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
 286                 return;
 287         }
 288
 289         kfree_skb(skb);
 290 }
 291
 292 static struct request_sock_ops dccp6_request_sock_ops = {
 293         .family         = AF_INET6,
 294         .obj_size       = sizeof(struct dccp6_request_sock),
 295         .rtx_syn_ack    = dccp_v6_send_response,
 296         .send_ack       = dccp_reqsk_send_ack,
 297         .destructor     = dccp_v6_reqsk_destructor,
 298         .send_reset     = dccp_v6_ctl_send_reset,
 299         .syn_ack_timeout = dccp_syn_ack_timeout,
 300 };
 301
 302 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 303 {
 304         struct request_sock *req;
 305         struct dccp_request_sock *dreq;
 306         struct inet_request_sock *ireq;
 307         struct ipv6_pinfo *np = inet6_sk(sk);
 308         const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
 309         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 310
 311         if (skb->protocol == htons(ETH_P_IP))
 312                 return dccp_v4_conn_request(sk, skb);
 313
 314         if (!ipv6_unicast_destination(skb))
 315                 return 0;       /* discard, don't send a reset here */
 316
 317         if (dccp_bad_service_code(sk, service)) {
 318                 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
 319                 goto drop;
 320         }
 321         /*
 322          * There are no SYN attacks on IPv6, yet...
 323          */
 324         dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
 325         if (inet_csk_reqsk_queue_is_full(sk))
 326                 goto drop;
 327
 328         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
 329                 goto drop;
 330
 331         req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
 332         if (req == NULL)
 333                 goto drop;
 334
 335         if (dccp_reqsk_init(req, dccp_sk(sk), skb))
 336                 goto drop_and_free;
 337
 338         dreq = dccp_rsk(req);
 339         if (dccp_parse_options(sk, dreq, skb))
 340                 goto drop_and_free;
 341
 342         if (security_inet_conn_request(sk, skb, req))
 343                 goto drop_and_free;
 344
 345         ireq = inet_rsk(req);
 346         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 347         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 348         ireq->ireq_family = AF_INET6;
 349
 350         if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
 351             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
 352             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
 353                 atomic_inc(&skb->users);
 354                 ireq->pktopts = skb;
 355         }
 356         ireq->ir_iif = sk->sk_bound_dev_if;
 357
 358         /* So that link locals have meaning */
 359         if (!sk->sk_bound_dev_if &&
 360             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 361                 ireq->ir_iif = inet6_iif(skb);
 362
 363         /*
 364          * Step 3: Process LISTEN state
 365          *
 366          *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
 367          *
 368          * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
 369          */
 370         dreq->dreq_isr     = dcb->dccpd_seq;
 371         dreq->dreq_gsr     = dreq->dreq_isr;
 372         dreq->dreq_iss     = dccp_v6_init_sequence(skb);
 373         dreq->dreq_gss     = dreq->dreq_iss;
 374         dreq->dreq_service = service;
 375
 376         if (dccp_v6_send_response(sk, req))
 377                 goto drop_and_free;
 378
 379         inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
 380         return 0;
 381
 382 drop_and_free:
 383         reqsk_free(req);
 384 drop:
 385         __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
 386         return -1;
 387 }
 388
 389 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
 390                                               struct sk_buff *skb,
 391                                               struct request_sock *req,
 392                                               struct dst_entry *dst,
 393                                               struct request_sock *req_unhash,
 394                                               bool *own_req)
 395 {
 396         struct inet_request_sock *ireq = inet_rsk(req);
 397         struct ipv6_pinfo *newnp;
 398         const struct ipv6_pinfo *np = inet6_sk(sk);
 399         struct ipv6_txoptions *opt;
 400         struct inet_sock *newinet;
 401         struct dccp6_sock *newdp6;
 402         struct sock *newsk;
 403
 404         if (skb->protocol == htons(ETH_P_IP)) {
 405                 /*
 406                  *      v6 mapped
 407                  */
 408                 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
 409                                                   req_unhash, own_req);
 410                 if (newsk == NULL)
 411                         return NULL;
 412
 413                 newdp6 = (struct dccp6_sock *)newsk;
 414                 newinet = inet_sk(newsk);
 415                 newinet->pinet6 = &newdp6->inet6;
 416                 newnp = inet6_sk(newsk);
 417
 418                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 419
 420                 newnp->saddr = newsk->sk_v6_rcv_saddr;
 421
 422                 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
 423                 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
 424                 newnp->pktoptions  = NULL;
 425                 newnp->opt         = NULL;
 426                 newnp->mcast_oif   = inet6_iif(skb);
 427                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
 428
 429                 /*
 430                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
 431                  * here, dccp_create_openreq_child now does this for us, see the comment in
 432                  * that function for the gory details. -acme
 433                  */
 434
 435                 /* It is tricky place. Until this moment IPv4 tcp
 436                    worked with IPv6 icsk.icsk_af_ops.
 437                    Sync it now.
 438                  */
 439                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
 440
 441                 return newsk;
 442         }
 443
 444
 445         if (sk_acceptq_is_full(sk))
 446                 goto out_overflow;
 447
 448         if (!dst) {
 449                 struct flowi6 fl6;
 450
 451                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
 452                 if (!dst)
 453                         goto out;
 454         }
 455
 456         newsk = dccp_create_openreq_child(sk, req, skb);
 457         if (newsk == NULL)
 458                 goto out_nonewsk;
 459
 460         /*
 461          * No need to charge this sock to the relevant IPv6 refcnt debug socks
 462          * count here, dccp_create_openreq_child now does this for us, see the
 463          * comment in that function for the gory details. -acme
 464          */
 465
 466         ip6_dst_store(newsk, dst, NULL, NULL);
 467         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
 468                                                       NETIF_F_TSO);
 469         newdp6 = (struct dccp6_sock *)newsk;
 470         newinet = inet_sk(newsk);
 471         newinet->pinet6 = &newdp6->inet6;
 472         newnp = inet6_sk(newsk);
 473
 474         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 475
 476         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
 477         newnp->saddr            = ireq->ir_v6_loc_addr;
 478         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
 479         newsk->sk_bound_dev_if  = ireq->ir_iif;
 480
 481         /* Now IPv6 options...
 482
 483            First: no IPv4 options.
 484          */
 485         newinet->inet_opt = NULL;
 486
 487         /* Clone RX bits */
 488         newnp->rxopt.all = np->rxopt.all;
 489
 490         newnp->pktoptions = NULL;
 491         newnp->opt        = NULL;
 492         newnp->mcast_oif  = inet6_iif(skb);
 493         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
 494
 495         /*
 496          * Clone native IPv6 options from listening socket (if any)
 497          *
 498          * Yes, keeping reference count would be much more clever, but we make
 499          * one more one thing there: reattach optmem to newsk.
 500          */
 501         opt = ireq->ipv6_opt;
 502         if (!opt)
 503                 opt = rcu_dereference(np->opt);
 504         if (opt) {
 505                 opt = ipv6_dup_options(newsk, opt);
 506                 RCU_INIT_POINTER(newnp->opt, opt);
 507         }
 508         inet_csk(newsk)->icsk_ext_hdr_len = 0;
 509         if (opt)
 510                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
 511                                                     opt->opt_flen;
 512
 513         dccp_sync_mss(newsk, dst_mtu(dst));
 514
 515         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
 516         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 517
 518         if (__inet_inherit_port(sk, newsk) < 0) {
 519                 inet_csk_prepare_forced_close(newsk);
 520                 dccp_done(newsk);
 521                 goto out;
 522         }
 523         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
 524         /* Clone pktoptions received with SYN, if we own the req */
 525         if (*own_req && ireq->pktopts) {
 526                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
 527                 consume_skb(ireq->pktopts);
 528                 ireq->pktopts = NULL;
 529                 if (newnp->pktoptions)
 530                         skb_set_owner_r(newnp->pktoptions, newsk);
 531         }
 532
 533         return newsk;
 534
 535 out_overflow:
 536         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
 537 out_nonewsk:
 538         dst_release(dst);
 539 out:
 540         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
 541         return NULL;
 542 }
 543
 544 /* The socket must have it's spinlock held when we get
 545  * here.
 546  *
 547  * We have a potential double-lock case here, so even when
 548  * doing backlog processing we use the BH locking scheme.
 549  * This is because we cannot sleep with the original spinlock
 550  * held.
 551  */
 552 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 553 {
 554         struct ipv6_pinfo *np = inet6_sk(sk);
 555         struct sk_buff *opt_skb = NULL;
 556
 557         /* Imagine: socket is IPv6. IPv4 packet arrives,
 558            goes to IPv4 receive handler and backlogged.
 559            From backlog it always goes here. Kerboom...
 560            Fortunately, dccp_rcv_established and rcv_established
 561            handle them correctly, but it is not case with
 562            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
 563          */
 564
 565         if (skb->protocol == htons(ETH_P_IP))
 566                 return dccp_v4_do_rcv(sk, skb);
 567
 568         if (sk_filter(sk, skb))
 569                 goto discard;
 570
 571         /*
 572          * socket locking is here for SMP purposes as backlog rcv is currently
 573          * called with bh processing disabled.
 574          */
 575
 576         /* Do Stevens' IPV6_PKTOPTIONS.
 577
 578            Yes, guys, it is the only place in our code, where we
 579            may make it not affecting IPv4.
 580            The rest of code is protocol independent,
 581            and I do not like idea to uglify IPv4.
 582
 583            Actually, all the idea behind IPV6_PKTOPTIONS
 584            looks not very well thought. For now we latch
 585            options, received in the last packet, enqueued
 586            by tcp. Feel free to propose better solution.
 587                                                --ANK (980728)
 588          */
 589         if (np->rxopt.all)
 590         /*
 591          * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
 592          *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
 593          */
 594                 opt_skb = skb_clone(skb, GFP_ATOMIC);
 595
 596         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
 597                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
 598                         goto reset;
 599                 if (opt_skb) {
 600                         /* XXX This is where we would goto ipv6_pktoptions. */
 601                         __kfree_skb(opt_skb);
 602                 }
 603                 return 0;
 604         }
 605
 606         /*
 607          *  Step 3: Process LISTEN state
 608          *     If S.state == LISTEN,
 609          *       If P.type == Request or P contains a valid Init Cookie option,
 610          *            (* Must scan the packet's options to check for Init
 611          *               Cookies.  Only Init Cookies are processed here,
 612          *               however; other options are processed in Step 8.  This
 613          *               scan need only be performed if the endpoint uses Init
 614          *               Cookies *)
 615          *            (* Generate a new socket and switch to that socket *)
 616          *            Set S := new socket for this port pair
 617          *            S.state = RESPOND
 618          *            Choose S.ISS (initial seqno) or set from Init Cookies
 619          *            Initialize S.GAR := S.ISS
 620          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
 621          *            Continue with S.state == RESPOND
 622          *            (* A Response packet will be generated in Step 11 *)
 623          *       Otherwise,
 624          *            Generate Reset(No Connection) unless P.type == Reset
 625          *            Drop packet and return
 626          *
 627          * NOTE: the check for the packet types is done in
 628          *       dccp_rcv_state_process
 629          */
 630
 631         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
 632                 goto reset;
 633         if (opt_skb) {
 634                 /* XXX This is where we would goto ipv6_pktoptions. */
 635                 __kfree_skb(opt_skb);
 636         }
 637         return 0;
 638
 639 reset:
 640         dccp_v6_ctl_send_reset(sk, skb);
 641 discard:
 642         if (opt_skb != NULL)
 643                 __kfree_skb(opt_skb);
 644         kfree_skb(skb);
 645         return 0;
 646 }
 647
 648 static int dccp_v6_rcv(struct sk_buff *skb)
 649 {
 650         const struct dccp_hdr *dh;
 651         bool refcounted;
 652         struct sock *sk;
 653         int min_cov;
 654
 655         /* Step 1: Check header basics */
 656
 657         if (dccp_invalid_packet(skb))
 658                 goto discard_it;
 659
 660         /* Step 1: If header checksum is incorrect, drop packet and return. */
 661         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
 662                                      &ipv6_hdr(skb)->daddr)) {
 663                 DCCP_WARN("dropped packet with invalid checksum\n");
 664                 goto discard_it;
 665         }
 666
 667         dh = dccp_hdr(skb);
 668
 669         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
 670         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
 671
 672         if (dccp_packet_without_ack(skb))
 673                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
 674         else
 675                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
 676
 677 lookup:
 678         sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
 679                                 dh->dccph_sport, dh->dccph_dport,
 680                                 inet6_iif(skb), &refcounted);
 681         if (!sk) {
 682                 dccp_pr_debug("failed to look up flow ID in table and "
 683                               "get corresponding socket\n");
 684                 goto no_dccp_socket;
 685         }
 686
 687         /*
 688          * Step 2:
 689          *      ... or S.state == TIMEWAIT,
 690          *              Generate Reset(No Connection) unless P.type == Reset
 691          *              Drop packet and return
 692          */
 693         if (sk->sk_state == DCCP_TIME_WAIT) {
 694                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
 695                 inet_twsk_put(inet_twsk(sk));
 696                 goto no_dccp_socket;
 697         }
 698
 699         if (sk->sk_state == DCCP_NEW_SYN_RECV) {
 700                 struct request_sock *req = inet_reqsk(sk);
 701                 struct sock *nsk;
 702
 703                 sk = req->rsk_listener;
 704                 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
 705                         inet_csk_reqsk_queue_drop_and_put(sk, req);
 706                         goto lookup;
 707                 }
 708                 sock_hold(sk);
 709                 refcounted = true;
 710                 nsk = dccp_check_req(sk, skb, req);
 711                 if (!nsk) {
 712                         reqsk_put(req);
 713                         goto discard_and_relse;
 714                 }
 715                 if (nsk == sk) {
 716                         reqsk_put(req);
 717                 } else if (dccp_child_process(sk, nsk, skb)) {
 718                         dccp_v6_ctl_send_reset(sk, skb);
 719                         goto discard_and_relse;
 720                 } else {
 721                         sock_put(sk);
 722                         return 0;
 723                 }
 724         }
 725         /*
 726          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
 727          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
 728          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
 729          */
 730         min_cov = dccp_sk(sk)->dccps_pcrlen;
 731         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
 732                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
 733                               dh->dccph_cscov, min_cov);
 734                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
 735                 goto discard_and_relse;
 736         }
 737
 738         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 739                 goto discard_and_relse;
 740
 741         return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4) ? -1 : 0;
 742
 743 no_dccp_socket:
 744         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 745                 goto discard_it;
 746         /*
 747          * Step 2:
 748          *      If no socket ...
 749          *              Generate Reset(No Connection) unless P.type == Reset
 750          *              Drop packet and return
 751          */
 752         if (dh->dccph_type != DCCP_PKT_RESET) {
 753                 DCCP_SKB_CB(skb)->dccpd_reset_code =
 754                                         DCCP_RESET_CODE_NO_CONNECTION;
 755                 dccp_v6_ctl_send_reset(sk, skb);
 756         }
 757
 758 discard_it:
 759         kfree_skb(skb);
 760         return 0;
 761
 762 discard_and_relse:
 763         if (refcounted)
 764                 sock_put(sk);
 765         goto discard_it;
 766 }
 767
 768 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 769                            int addr_len)
 770 {
 771         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
 772         struct inet_connection_sock *icsk = inet_csk(sk);
 773         struct inet_sock *inet = inet_sk(sk);
 774         struct ipv6_pinfo *np = inet6_sk(sk);
 775         struct dccp_sock *dp = dccp_sk(sk);
 776         struct in6_addr *saddr = NULL, *final_p, final;
 777         struct ipv6_txoptions *opt;
 778         struct flowi6 fl6;
 779         struct dst_entry *dst;
 780         int addr_type;
 781         int err;
 782
 783         dp->dccps_role = DCCP_ROLE_CLIENT;
 784
 785         if (addr_len < SIN6_LEN_RFC2133)
 786                 return -EINVAL;
 787
 788         if (usin->sin6_family != AF_INET6)
 789                 return -EAFNOSUPPORT;
 790
 791         memset(&fl6, 0, sizeof(fl6));
 792
 793         if (np->sndflow) {
 794                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
 795                 IP6_ECN_flow_init(fl6.flowlabel);
 796                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
 797                         struct ip6_flowlabel *flowlabel;
 798                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 799                         if (flowlabel == NULL)
 800                                 return -EINVAL;
 801                         fl6_sock_release(flowlabel);
 802                 }
 803         }
 804         /*
 805          * connect() to INADDR_ANY means loopback (BSD'ism).
 806          */
 807         if (ipv6_addr_any(&usin->sin6_addr))
 808                 usin->sin6_addr.s6_addr[15] = 1;
 809
 810         addr_type = ipv6_addr_type(&usin->sin6_addr);
 811
 812         if (addr_type & IPV6_ADDR_MULTICAST)
 813                 return -ENETUNREACH;
 814
 815         if (addr_type & IPV6_ADDR_LINKLOCAL) {
 816                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 817                     usin->sin6_scope_id) {
 818                         /* If interface is set while binding, indices
 819                          * must coincide.
 820                          */
 821                         if (sk->sk_bound_dev_if &&
 822                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 823                                 return -EINVAL;
 824
 825                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 826                 }
 827
 828                 /* Connect to link-local address requires an interface */
 829                 if (!sk->sk_bound_dev_if)
 830                         return -EINVAL;
 831         }
 832
 833         sk->sk_v6_daddr = usin->sin6_addr;
 834         np->flow_label = fl6.flowlabel;
 835
 836         /*
 837          * DCCP over IPv4
 838          */
 839         if (addr_type == IPV6_ADDR_MAPPED) {
 840                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 841                 struct sockaddr_in sin;
 842
 843                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 844
 845                 if (__ipv6_only_sock(sk))
 846                         return -ENETUNREACH;
 847
 848                 sin.sin_family = AF_INET;
 849                 sin.sin_port = usin->sin6_port;
 850                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 851
 852                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
 853                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
 854
 855                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 856                 if (err) {
 857                         icsk->icsk_ext_hdr_len = exthdrlen;
 858                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
 859                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
 860                         goto failure;
 861                 }
 862                 np->saddr = sk->sk_v6_rcv_saddr;
 863                 return err;
 864         }
 865
 866         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 867                 saddr = &sk->sk_v6_rcv_saddr;
 868
 869         fl6.flowi6_proto = IPPROTO_DCCP;
 870         fl6.daddr = sk->sk_v6_daddr;
 871         fl6.saddr = saddr ? *saddr : np->saddr;
 872         fl6.flowi6_oif = sk->sk_bound_dev_if;
 873         fl6.fl6_dport = usin->sin6_port;
 874         fl6.fl6_sport = inet->inet_sport;
 875         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 876
 877         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 878         final_p = fl6_update_dst(&fl6, opt, &final);
 879
 880         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 881         if (IS_ERR(dst)) {
 882                 err = PTR_ERR(dst);
 883                 goto failure;
 884         }
 885
 886         if (saddr == NULL) {
 887                 saddr = &fl6.saddr;
 888                 sk->sk_v6_rcv_saddr = *saddr;
 889         }
 890
 891         /* set the source address */
 892         np->saddr = *saddr;
 893         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 894
 895         ip6_dst_store(sk, dst, NULL, NULL);
 896
 897         icsk->icsk_ext_hdr_len = 0;
 898         if (opt)
 899                 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
 900
 901         inet->inet_dport = usin->sin6_port;
 902
 903         dccp_set_state(sk, DCCP_REQUESTING);
 904         err = inet6_hash_connect(&dccp_death_row, sk);
 905         if (err)
 906                 goto late_failure;
 907
 908         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
 909                                                       sk->sk_v6_daddr.s6_addr32,
 910                                                       inet->inet_sport,
 911                                                       inet->inet_dport);
 912         err = dccp_connect(sk);
 913         if (err)
 914                 goto late_failure;
 915
 916         return 0;
 917
 918 late_failure:
 919         dccp_set_state(sk, DCCP_CLOSED);
 920         __sk_dst_reset(sk);
 921 failure:
 922         inet->inet_dport = 0;
 923         sk->sk_route_caps = 0;
 924         return err;
 925 }
 926
 927 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
 928         .queue_xmit        = inet6_csk_xmit,
 929         .send_check        = dccp_v6_send_check,
 930         .rebuild_header    = inet6_sk_rebuild_header,
 931         .conn_request      = dccp_v6_conn_request,
 932         .syn_recv_sock     = dccp_v6_request_recv_sock,
 933         .net_header_len    = sizeof(struct ipv6hdr),
 934         .setsockopt        = ipv6_setsockopt,
 935         .getsockopt        = ipv6_getsockopt,
 936         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 937         .sockaddr_len      = sizeof(struct sockaddr_in6),
 938         .bind_conflict     = inet6_csk_bind_conflict,
 939 #ifdef CONFIG_COMPAT
 940         .compat_setsockopt = compat_ipv6_setsockopt,
 941         .compat_getsockopt = compat_ipv6_getsockopt,
 942 #endif
 943 };
 944
 945 /*
 946  *      DCCP over IPv4 via INET6 API
 947  */
 948 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
 949         .queue_xmit        = ip_queue_xmit,
 950         .send_check        = dccp_v4_send_check,
 951         .rebuild_header    = inet_sk_rebuild_header,
 952         .conn_request      = dccp_v6_conn_request,
 953         .syn_recv_sock     = dccp_v6_request_recv_sock,
 954         .net_header_len    = sizeof(struct iphdr),
 955         .setsockopt        = ipv6_setsockopt,
 956         .getsockopt        = ipv6_getsockopt,
 957         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 958         .sockaddr_len      = sizeof(struct sockaddr_in6),
 959 #ifdef CONFIG_COMPAT
 960         .compat_setsockopt = compat_ipv6_setsockopt,
 961         .compat_getsockopt = compat_ipv6_getsockopt,
 962 #endif
 963 };
 964
 965 /* NOTE: A lot of things set to zero explicitly by call to
 966  *       sk_alloc() so need not be done here.
 967  */
 968 static int dccp_v6_init_sock(struct sock *sk)
 969 {
 970         static __u8 dccp_v6_ctl_sock_initialized;
 971         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
 972
 973         if (err == 0) {
 974                 if (unlikely(!dccp_v6_ctl_sock_initialized))
 975                         dccp_v6_ctl_sock_initialized = 1;
 976                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
 977         }
 978
 979         return err;
 980 }
 981
 982 static void dccp_v6_destroy_sock(struct sock *sk)
 983 {
 984         dccp_destroy_sock(sk);
 985         inet6_destroy_sock(sk);
 986 }
 987
 988 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
 989         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
 990 };
 991
 992 static struct proto dccp_v6_prot = {
 993         .name              = "DCCPv6",
 994         .owner             = THIS_MODULE,
 995         .close             = dccp_close,
 996         .connect           = dccp_v6_connect,
 997         .disconnect        = dccp_disconnect,
 998         .ioctl             = dccp_ioctl,
 999         .init              = dccp_v6_init_sock,
1000         .setsockopt        = dccp_setsockopt,
1001         .getsockopt        = dccp_getsockopt,
1002         .sendmsg           = dccp_sendmsg,
1003         .recvmsg           = dccp_recvmsg,
1004         .backlog_rcv       = dccp_v6_do_rcv,
1005         .hash              = inet6_hash,
1006         .unhash            = inet_unhash,
1007         .accept            = inet_csk_accept,
1008         .get_port          = inet_csk_get_port,
1009         .shutdown          = dccp_shutdown,
1010         .destroy           = dccp_v6_destroy_sock,
1011         .orphan_count      = &dccp_orphan_count,
1012         .max_header        = MAX_DCCP_HEADER,
1013         .obj_size          = sizeof(struct dccp6_sock),
1014         .slab_flags        = SLAB_DESTROY_BY_RCU,
1015         .rsk_prot          = &dccp6_request_sock_ops,
1016         .twsk_prot         = &dccp6_timewait_sock_ops,
1017         .h.hashinfo        = &dccp_hashinfo,
1018 #ifdef CONFIG_COMPAT
1019         .compat_setsockopt = compat_dccp_setsockopt,
1020         .compat_getsockopt = compat_dccp_getsockopt,
1021 #endif
1022 };
1023
1024 static const struct inet6_protocol dccp_v6_protocol = {
1025         .handler        = dccp_v6_rcv,
1026         .err_handler    = dccp_v6_err,
1027         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1028 };
1029
1030 static const struct proto_ops inet6_dccp_ops = {
1031         .family            = PF_INET6,
1032         .owner             = THIS_MODULE,
1033         .release           = inet6_release,
1034         .bind              = inet6_bind,
1035         .connect           = inet_stream_connect,
1036         .socketpair        = sock_no_socketpair,
1037         .accept            = inet_accept,
1038         .getname           = inet6_getname,
1039         .poll              = dccp_poll,
1040         .ioctl             = inet6_ioctl,
1041         .listen            = inet_dccp_listen,
1042         .shutdown          = inet_shutdown,
1043         .setsockopt        = sock_common_setsockopt,
1044         .getsockopt        = sock_common_getsockopt,
1045         .sendmsg           = inet_sendmsg,
1046         .recvmsg           = sock_common_recvmsg,
1047         .mmap              = sock_no_mmap,
1048         .sendpage          = sock_no_sendpage,
1049 #ifdef CONFIG_COMPAT
1050         .compat_setsockopt = compat_sock_common_setsockopt,
1051         .compat_getsockopt = compat_sock_common_getsockopt,
1052 #endif
1053 };
1054
1055 static struct inet_protosw dccp_v6_protosw = {
1056         .type           = SOCK_DCCP,
1057         .protocol       = IPPROTO_DCCP,
1058         .prot           = &dccp_v6_prot,
1059         .ops            = &inet6_dccp_ops,
1060         .flags          = INET_PROTOSW_ICSK,
1061 };
1062
1063 static int __net_init dccp_v6_init_net(struct net *net)
1064 {
1065         if (dccp_hashinfo.bhash == NULL)
1066                 return -ESOCKTNOSUPPORT;
1067
1068         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1069                                     SOCK_DCCP, IPPROTO_DCCP, net);
1070 }
1071
1072 static void __net_exit dccp_v6_exit_net(struct net *net)
1073 {
1074         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1075 }
1076
1077 static struct pernet_operations dccp_v6_ops = {
1078         .init   = dccp_v6_init_net,
1079         .exit   = dccp_v6_exit_net,
1080 };
1081
1082 static int __init dccp_v6_init(void)
1083 {
1084         int err = proto_register(&dccp_v6_prot, 1);
1085
1086         if (err != 0)
1087                 goto out;
1088
1089         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1090         if (err != 0)
1091                 goto out_unregister_proto;
1092
1093         inet6_register_protosw(&dccp_v6_protosw);
1094
1095         err = register_pernet_subsys(&dccp_v6_ops);
1096         if (err != 0)
1097                 goto out_destroy_ctl_sock;
1098 out:
1099         return err;
1100
1101 out_destroy_ctl_sock:
1102         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1103         inet6_unregister_protosw(&dccp_v6_protosw);
1104 out_unregister_proto:
1105         proto_unregister(&dccp_v6_prot);
1106         goto out;
1107 }
1108
1109 static void __exit dccp_v6_exit(void)
1110 {
1111         unregister_pernet_subsys(&dccp_v6_ops);
1112         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1113         inet6_unregister_protosw(&dccp_v6_protosw);
1114         proto_unregister(&dccp_v6_prot);
1115 }
1116
1117 module_init(dccp_v6_init);
1118 module_exit(dccp_v6_exit);
1119
1120 /*
1121  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1122  * values directly, Also cover the case where the protocol is not specified,
1123  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1124  */
1125 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1126 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1127 MODULE_LICENSE("GPL");
1128 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1129 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");