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 <[email protected]>
   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->mcast_oif   = inet6_iif(skb);
 430                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
 431
 432                 /*
 433                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
 434                  * here, dccp_create_openreq_child now does this for us, see the comment in
 435                  * that function for the gory details. -acme
 436                  */
 437
 438                 /* It is tricky place. Until this moment IPv4 tcp
 439                    worked with IPv6 icsk.icsk_af_ops.
 440                    Sync it now.
 441                  */
 442                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
 443
 444                 return newsk;
 445         }
 446
 447
 448         if (sk_acceptq_is_full(sk))
 449                 goto out_overflow;
 450
 451         if (!dst) {
 452                 struct flowi6 fl6;
 453
 454                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
 455                 if (!dst)
 456                         goto out;
 457         }
 458
 459         newsk = dccp_create_openreq_child(sk, req, skb);
 460         if (newsk == NULL)
 461                 goto out_nonewsk;
 462
 463         /*
 464          * No need to charge this sock to the relevant IPv6 refcnt debug socks
 465          * count here, dccp_create_openreq_child now does this for us, see the
 466          * comment in that function for the gory details. -acme
 467          */
 468
 469         ip6_dst_store(newsk, dst, NULL, NULL);
 470         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
 471                                                       NETIF_F_TSO);
 472         newdp6 = (struct dccp6_sock *)newsk;
 473         newinet = inet_sk(newsk);
 474         newinet->pinet6 = &newdp6->inet6;
 475         newnp = inet6_sk(newsk);
 476
 477         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 478
 479         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
 480         newnp->saddr            = ireq->ir_v6_loc_addr;
 481         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
 482         newsk->sk_bound_dev_if  = ireq->ir_iif;
 483
 484         /* Now IPv6 options...
 485
 486            First: no IPv4 options.
 487          */
 488         newinet->inet_opt = NULL;
 489
 490         /* Clone RX bits */
 491         newnp->rxopt.all = np->rxopt.all;
 492
 493         newnp->pktoptions = NULL;
 494         newnp->opt        = NULL;
 495         newnp->mcast_oif  = inet6_iif(skb);
 496         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
 497
 498         /*
 499          * Clone native IPv6 options from listening socket (if any)
 500          *
 501          * Yes, keeping reference count would be much more clever, but we make
 502          * one more one thing there: reattach optmem to newsk.
 503          */
 504         opt = ireq->ipv6_opt;
 505         if (!opt)
 506                 opt = rcu_dereference(np->opt);
 507         if (opt) {
 508                 opt = ipv6_dup_options(newsk, opt);
 509                 RCU_INIT_POINTER(newnp->opt, opt);
 510         }
 511         inet_csk(newsk)->icsk_ext_hdr_len = 0;
 512         if (opt)
 513                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
 514                                                     opt->opt_flen;
 515
 516         dccp_sync_mss(newsk, dst_mtu(dst));
 517
 518         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
 519         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 520
 521         if (__inet_inherit_port(sk, newsk) < 0) {
 522                 inet_csk_prepare_forced_close(newsk);
 523                 dccp_done(newsk);
 524                 goto out;
 525         }
 526         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
 527         /* Clone pktoptions received with SYN, if we own the req */
 528         if (*own_req && ireq->pktopts) {
 529                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
 530                 consume_skb(ireq->pktopts);
 531                 ireq->pktopts = NULL;
 532                 if (newnp->pktoptions)
 533                         skb_set_owner_r(newnp->pktoptions, newsk);
 534         }
 535
 536         return newsk;
 537
 538 out_overflow:
 539         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
 540 out_nonewsk:
 541         dst_release(dst);
 542 out:
 543         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
 544         return NULL;
 545 }
 546
 547 /* The socket must have it's spinlock held when we get
 548  * here.
 549  *
 550  * We have a potential double-lock case here, so even when
 551  * doing backlog processing we use the BH locking scheme.
 552  * This is because we cannot sleep with the original spinlock
 553  * held.
 554  */
 555 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 556 {
 557         struct ipv6_pinfo *np = inet6_sk(sk);
 558         struct sk_buff *opt_skb = NULL;
 559
 560         /* Imagine: socket is IPv6. IPv4 packet arrives,
 561            goes to IPv4 receive handler and backlogged.
 562            From backlog it always goes here. Kerboom...
 563            Fortunately, dccp_rcv_established and rcv_established
 564            handle them correctly, but it is not case with
 565            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
 566          */
 567
 568         if (skb->protocol == htons(ETH_P_IP))
 569                 return dccp_v4_do_rcv(sk, skb);
 570
 571         if (sk_filter(sk, skb))
 572                 goto discard;
 573
 574         /*
 575          * socket locking is here for SMP purposes as backlog rcv is currently
 576          * called with bh processing disabled.
 577          */
 578
 579         /* Do Stevens' IPV6_PKTOPTIONS.
 580
 581            Yes, guys, it is the only place in our code, where we
 582            may make it not affecting IPv4.
 583            The rest of code is protocol independent,
 584            and I do not like idea to uglify IPv4.
 585
 586            Actually, all the idea behind IPV6_PKTOPTIONS
 587            looks not very well thought. For now we latch
 588            options, received in the last packet, enqueued
 589            by tcp. Feel free to propose better solution.
 590                                                --ANK (980728)
 591          */
 592         if (np->rxopt.all)
 593         /*
 594          * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
 595          *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
 596          */
 597                 opt_skb = skb_clone(skb, GFP_ATOMIC);
 598
 599         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
 600                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
 601                         goto reset;
 602                 if (opt_skb) {
 603                         /* XXX This is where we would goto ipv6_pktoptions. */
 604                         __kfree_skb(opt_skb);
 605                 }
 606                 return 0;
 607         }
 608
 609         /*
 610          *  Step 3: Process LISTEN state
 611          *     If S.state == LISTEN,
 612          *       If P.type == Request or P contains a valid Init Cookie option,
 613          *            (* Must scan the packet's options to check for Init
 614          *               Cookies.  Only Init Cookies are processed here,
 615          *               however; other options are processed in Step 8.  This
 616          *               scan need only be performed if the endpoint uses Init
 617          *               Cookies *)
 618          *            (* Generate a new socket and switch to that socket *)
 619          *            Set S := new socket for this port pair
 620          *            S.state = RESPOND
 621          *            Choose S.ISS (initial seqno) or set from Init Cookies
 622          *            Initialize S.GAR := S.ISS
 623          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
 624          *            Continue with S.state == RESPOND
 625          *            (* A Response packet will be generated in Step 11 *)
 626          *       Otherwise,
 627          *            Generate Reset(No Connection) unless P.type == Reset
 628          *            Drop packet and return
 629          *
 630          * NOTE: the check for the packet types is done in
 631          *       dccp_rcv_state_process
 632          */
 633
 634         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
 635                 goto reset;
 636         if (opt_skb) {
 637                 /* XXX This is where we would goto ipv6_pktoptions. */
 638                 __kfree_skb(opt_skb);
 639         }
 640         return 0;
 641
 642 reset:
 643         dccp_v6_ctl_send_reset(sk, skb);
 644 discard:
 645         if (opt_skb != NULL)
 646                 __kfree_skb(opt_skb);
 647         kfree_skb(skb);
 648         return 0;
 649 }
 650
 651 static int dccp_v6_rcv(struct sk_buff *skb)
 652 {
 653         const struct dccp_hdr *dh;
 654         bool refcounted;
 655         struct sock *sk;
 656         int min_cov;
 657
 658         /* Step 1: Check header basics */
 659
 660         if (dccp_invalid_packet(skb))
 661                 goto discard_it;
 662
 663         /* Step 1: If header checksum is incorrect, drop packet and return. */
 664         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
 665                                      &ipv6_hdr(skb)->daddr)) {
 666                 DCCP_WARN("dropped packet with invalid checksum\n");
 667                 goto discard_it;
 668         }
 669
 670         dh = dccp_hdr(skb);
 671
 672         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
 673         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
 674
 675         if (dccp_packet_without_ack(skb))
 676                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
 677         else
 678                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
 679
 680 lookup:
 681         sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
 682                                 dh->dccph_sport, dh->dccph_dport,
 683                                 inet6_iif(skb), &refcounted);
 684         if (!sk) {
 685                 dccp_pr_debug("failed to look up flow ID in table and "
 686                               "get corresponding socket\n");
 687                 goto no_dccp_socket;
 688         }
 689
 690         /*
 691          * Step 2:
 692          *      ... or S.state == TIMEWAIT,
 693          *              Generate Reset(No Connection) unless P.type == Reset
 694          *              Drop packet and return
 695          */
 696         if (sk->sk_state == DCCP_TIME_WAIT) {
 697                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
 698                 inet_twsk_put(inet_twsk(sk));
 699                 goto no_dccp_socket;
 700         }
 701
 702         if (sk->sk_state == DCCP_NEW_SYN_RECV) {
 703                 struct request_sock *req = inet_reqsk(sk);
 704                 struct sock *nsk;
 705
 706                 sk = req->rsk_listener;
 707                 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
 708                         inet_csk_reqsk_queue_drop_and_put(sk, req);
 709                         goto lookup;
 710                 }
 711                 sock_hold(sk);
 712                 refcounted = true;
 713                 nsk = dccp_check_req(sk, skb, req);
 714                 if (!nsk) {
 715                         reqsk_put(req);
 716                         goto discard_and_relse;
 717                 }
 718                 if (nsk == sk) {
 719                         reqsk_put(req);
 720                 } else if (dccp_child_process(sk, nsk, skb)) {
 721                         dccp_v6_ctl_send_reset(sk, skb);
 722                         goto discard_and_relse;
 723                 } else {
 724                         sock_put(sk);
 725                         return 0;
 726                 }
 727         }
 728         /*
 729          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
 730          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
 731          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
 732          */
 733         min_cov = dccp_sk(sk)->dccps_pcrlen;
 734         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
 735                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
 736                               dh->dccph_cscov, min_cov);
 737                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
 738                 goto discard_and_relse;
 739         }
 740
 741         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 742                 goto discard_and_relse;
 743
 744         return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4,
 745                                 refcounted) ? -1 : 0;
 746
 747 no_dccp_socket:
 748         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 749                 goto discard_it;
 750         /*
 751          * Step 2:
 752          *      If no socket ...
 753          *              Generate Reset(No Connection) unless P.type == Reset
 754          *              Drop packet and return
 755          */
 756         if (dh->dccph_type != DCCP_PKT_RESET) {
 757                 DCCP_SKB_CB(skb)->dccpd_reset_code =
 758                                         DCCP_RESET_CODE_NO_CONNECTION;
 759                 dccp_v6_ctl_send_reset(sk, skb);
 760         }
 761
 762 discard_it:
 763         kfree_skb(skb);
 764         return 0;
 765
 766 discard_and_relse:
 767         if (refcounted)
 768                 sock_put(sk);
 769         goto discard_it;
 770 }
 771
 772 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 773                            int addr_len)
 774 {
 775         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
 776         struct inet_connection_sock *icsk = inet_csk(sk);
 777         struct inet_sock *inet = inet_sk(sk);
 778         struct ipv6_pinfo *np = inet6_sk(sk);
 779         struct dccp_sock *dp = dccp_sk(sk);
 780         struct in6_addr *saddr = NULL, *final_p, final;
 781         struct ipv6_txoptions *opt;
 782         struct flowi6 fl6;
 783         struct dst_entry *dst;
 784         int addr_type;
 785         int err;
 786
 787         dp->dccps_role = DCCP_ROLE_CLIENT;
 788
 789         if (addr_len < SIN6_LEN_RFC2133)
 790                 return -EINVAL;
 791
 792         if (usin->sin6_family != AF_INET6)
 793                 return -EAFNOSUPPORT;
 794
 795         memset(&fl6, 0, sizeof(fl6));
 796
 797         if (np->sndflow) {
 798                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
 799                 IP6_ECN_flow_init(fl6.flowlabel);
 800                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
 801                         struct ip6_flowlabel *flowlabel;
 802                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 803                         if (flowlabel == NULL)
 804                                 return -EINVAL;
 805                         fl6_sock_release(flowlabel);
 806                 }
 807         }
 808         /*
 809          * connect() to INADDR_ANY means loopback (BSD'ism).
 810          */
 811         if (ipv6_addr_any(&usin->sin6_addr))
 812                 usin->sin6_addr.s6_addr[15] = 1;
 813
 814         addr_type = ipv6_addr_type(&usin->sin6_addr);
 815
 816         if (addr_type & IPV6_ADDR_MULTICAST)
 817                 return -ENETUNREACH;
 818
 819         if (addr_type & IPV6_ADDR_LINKLOCAL) {
 820                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 821                     usin->sin6_scope_id) {
 822                         /* If interface is set while binding, indices
 823                          * must coincide.
 824                          */
 825                         if (sk->sk_bound_dev_if &&
 826                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 827                                 return -EINVAL;
 828
 829                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 830                 }
 831
 832                 /* Connect to link-local address requires an interface */
 833                 if (!sk->sk_bound_dev_if)
 834                         return -EINVAL;
 835         }
 836
 837         sk->sk_v6_daddr = usin->sin6_addr;
 838         np->flow_label = fl6.flowlabel;
 839
 840         /*
 841          * DCCP over IPv4
 842          */
 843         if (addr_type == IPV6_ADDR_MAPPED) {
 844                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 845                 struct sockaddr_in sin;
 846
 847                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 848
 849                 if (__ipv6_only_sock(sk))
 850                         return -ENETUNREACH;
 851
 852                 sin.sin_family = AF_INET;
 853                 sin.sin_port = usin->sin6_port;
 854                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 855
 856                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
 857                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
 858
 859                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 860                 if (err) {
 861                         icsk->icsk_ext_hdr_len = exthdrlen;
 862                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
 863                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
 864                         goto failure;
 865                 }
 866                 np->saddr = sk->sk_v6_rcv_saddr;
 867                 return err;
 868         }
 869
 870         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 871                 saddr = &sk->sk_v6_rcv_saddr;
 872
 873         fl6.flowi6_proto = IPPROTO_DCCP;
 874         fl6.daddr = sk->sk_v6_daddr;
 875         fl6.saddr = saddr ? *saddr : np->saddr;
 876         fl6.flowi6_oif = sk->sk_bound_dev_if;
 877         fl6.fl6_dport = usin->sin6_port;
 878         fl6.fl6_sport = inet->inet_sport;
 879         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 880
 881         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 882         final_p = fl6_update_dst(&fl6, opt, &final);
 883
 884         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 885         if (IS_ERR(dst)) {
 886                 err = PTR_ERR(dst);
 887                 goto failure;
 888         }
 889
 890         if (saddr == NULL) {
 891                 saddr = &fl6.saddr;
 892                 sk->sk_v6_rcv_saddr = *saddr;
 893         }
 894
 895         /* set the source address */
 896         np->saddr = *saddr;
 897         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 898
 899         ip6_dst_store(sk, dst, NULL, NULL);
 900
 901         icsk->icsk_ext_hdr_len = 0;
 902         if (opt)
 903                 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
 904
 905         inet->inet_dport = usin->sin6_port;
 906
 907         dccp_set_state(sk, DCCP_REQUESTING);
 908         err = inet6_hash_connect(&dccp_death_row, sk);
 909         if (err)
 910                 goto late_failure;
 911
 912         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
 913                                                       sk->sk_v6_daddr.s6_addr32,
 914                                                       inet->inet_sport,
 915                                                       inet->inet_dport);
 916         err = dccp_connect(sk);
 917         if (err)
 918                 goto late_failure;
 919
 920         return 0;
 921
 922 late_failure:
 923         dccp_set_state(sk, DCCP_CLOSED);
 924         __sk_dst_reset(sk);
 925 failure:
 926         inet->inet_dport = 0;
 927         sk->sk_route_caps = 0;
 928         return err;
 929 }
 930
 931 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
 932         .queue_xmit        = inet6_csk_xmit,
 933         .send_check        = dccp_v6_send_check,
 934         .rebuild_header    = inet6_sk_rebuild_header,
 935         .conn_request      = dccp_v6_conn_request,
 936         .syn_recv_sock     = dccp_v6_request_recv_sock,
 937         .net_header_len    = sizeof(struct ipv6hdr),
 938         .setsockopt        = ipv6_setsockopt,
 939         .getsockopt        = ipv6_getsockopt,
 940         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 941         .sockaddr_len      = sizeof(struct sockaddr_in6),
 942 #ifdef CONFIG_COMPAT
 943         .compat_setsockopt = compat_ipv6_setsockopt,
 944         .compat_getsockopt = compat_ipv6_getsockopt,
 945 #endif
 946 };
 947
 948 /*
 949  *      DCCP over IPv4 via INET6 API
 950  */
 951 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
 952         .queue_xmit        = ip_queue_xmit,
 953         .send_check        = dccp_v4_send_check,
 954         .rebuild_header    = inet_sk_rebuild_header,
 955         .conn_request      = dccp_v6_conn_request,
 956         .syn_recv_sock     = dccp_v6_request_recv_sock,
 957         .net_header_len    = sizeof(struct iphdr),
 958         .setsockopt        = ipv6_setsockopt,
 959         .getsockopt        = ipv6_getsockopt,
 960         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 961         .sockaddr_len      = sizeof(struct sockaddr_in6),
 962 #ifdef CONFIG_COMPAT
 963         .compat_setsockopt = compat_ipv6_setsockopt,
 964         .compat_getsockopt = compat_ipv6_getsockopt,
 965 #endif
 966 };
 967
 968 /* NOTE: A lot of things set to zero explicitly by call to
 969  *       sk_alloc() so need not be done here.
 970  */
 971 static int dccp_v6_init_sock(struct sock *sk)
 972 {
 973         static __u8 dccp_v6_ctl_sock_initialized;
 974         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
 975
 976         if (err == 0) {
 977                 if (unlikely(!dccp_v6_ctl_sock_initialized))
 978                         dccp_v6_ctl_sock_initialized = 1;
 979                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
 980         }
 981
 982         return err;
 983 }
 984
 985 static void dccp_v6_destroy_sock(struct sock *sk)
 986 {
 987         dccp_destroy_sock(sk);
 988         inet6_destroy_sock(sk);
 989 }
 990
 991 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
 992         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
 993 };
 994
 995 static struct proto dccp_v6_prot = {
 996         .name              = "DCCPv6",
 997         .owner             = THIS_MODULE,
 998         .close             = dccp_close,
 999         .connect           = dccp_v6_connect,
1000         .disconnect        = dccp_disconnect,
1001         .ioctl             = dccp_ioctl,
1002         .init              = dccp_v6_init_sock,
1003         .setsockopt        = dccp_setsockopt,
1004         .getsockopt        = dccp_getsockopt,
1005         .sendmsg           = dccp_sendmsg,
1006         .recvmsg           = dccp_recvmsg,
1007         .backlog_rcv       = dccp_v6_do_rcv,
1008         .hash              = inet6_hash,
1009         .unhash            = inet_unhash,
1010         .accept            = inet_csk_accept,
1011         .get_port          = inet_csk_get_port,
1012         .shutdown          = dccp_shutdown,
1013         .destroy           = dccp_v6_destroy_sock,
1014         .orphan_count      = &dccp_orphan_count,
1015         .max_header        = MAX_DCCP_HEADER,
1016         .obj_size          = sizeof(struct dccp6_sock),
1017         .slab_flags        = SLAB_DESTROY_BY_RCU,
1018         .rsk_prot          = &dccp6_request_sock_ops,
1019         .twsk_prot         = &dccp6_timewait_sock_ops,
1020         .h.hashinfo        = &dccp_hashinfo,
1021 #ifdef CONFIG_COMPAT
1022         .compat_setsockopt = compat_dccp_setsockopt,
1023         .compat_getsockopt = compat_dccp_getsockopt,
1024 #endif
1025 };
1026
1027 static const struct inet6_protocol dccp_v6_protocol = {
1028         .handler        = dccp_v6_rcv,
1029         .err_handler    = dccp_v6_err,
1030         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1031 };
1032
1033 static const struct proto_ops inet6_dccp_ops = {
1034         .family            = PF_INET6,
1035         .owner             = THIS_MODULE,
1036         .release           = inet6_release,
1037         .bind              = inet6_bind,
1038         .connect           = inet_stream_connect,
1039         .socketpair        = sock_no_socketpair,
1040         .accept            = inet_accept,
1041         .getname           = inet6_getname,
1042         .poll              = dccp_poll,
1043         .ioctl             = inet6_ioctl,
1044         .listen            = inet_dccp_listen,
1045         .shutdown          = inet_shutdown,
1046         .setsockopt        = sock_common_setsockopt,
1047         .getsockopt        = sock_common_getsockopt,
1048         .sendmsg           = inet_sendmsg,
1049         .recvmsg           = sock_common_recvmsg,
1050         .mmap              = sock_no_mmap,
1051         .sendpage          = sock_no_sendpage,
1052 #ifdef CONFIG_COMPAT
1053         .compat_setsockopt = compat_sock_common_setsockopt,
1054         .compat_getsockopt = compat_sock_common_getsockopt,
1055 #endif
1056 };
1057
1058 static struct inet_protosw dccp_v6_protosw = {
1059         .type           = SOCK_DCCP,
1060         .protocol       = IPPROTO_DCCP,
1061         .prot           = &dccp_v6_prot,
1062         .ops            = &inet6_dccp_ops,
1063         .flags          = INET_PROTOSW_ICSK,
1064 };
1065
1066 static int __net_init dccp_v6_init_net(struct net *net)
1067 {
1068         if (dccp_hashinfo.bhash == NULL)
1069                 return -ESOCKTNOSUPPORT;
1070
1071         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1072                                     SOCK_DCCP, IPPROTO_DCCP, net);
1073 }
1074
1075 static void __net_exit dccp_v6_exit_net(struct net *net)
1076 {
1077         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1078 }
1079
1080 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
1081 {
1082         inet_twsk_purge(&dccp_hashinfo, AF_INET6);
1083 }
1084
1085 static struct pernet_operations dccp_v6_ops = {
1086         .init   = dccp_v6_init_net,
1087         .exit   = dccp_v6_exit_net,
1088         .exit_batch = dccp_v6_exit_batch,
1089 };
1090
1091 static int __init dccp_v6_init(void)
1092 {
1093         int err = proto_register(&dccp_v6_prot, 1);
1094
1095         if (err != 0)
1096                 goto out;
1097
1098         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1099         if (err != 0)
1100                 goto out_unregister_proto;
1101
1102         inet6_register_protosw(&dccp_v6_protosw);
1103
1104         err = register_pernet_subsys(&dccp_v6_ops);
1105         if (err != 0)
1106                 goto out_destroy_ctl_sock;
1107 out:
1108         return err;
1109
1110 out_destroy_ctl_sock:
1111         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1112         inet6_unregister_protosw(&dccp_v6_protosw);
1113 out_unregister_proto:
1114         proto_unregister(&dccp_v6_prot);
1115         goto out;
1116 }
1117
1118 static void __exit dccp_v6_exit(void)
1119 {
1120         unregister_pernet_subsys(&dccp_v6_ops);
1121         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1122         inet6_unregister_protosw(&dccp_v6_protosw);
1123         proto_unregister(&dccp_v6_prot);
1124 }
1125
1126 module_init(dccp_v6_init);
1127 module_exit(dccp_v6_exit);
1128
1129 /*
1130  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1131  * values directly, Also cover the case where the protocol is not specified,
1132  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1133  */
1134 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1135 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1136 MODULE_LICENSE("GPL");
1137 MODULE_AUTHOR("Arnaldo Carvalho de Melo <[email protected]>");
1138 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");