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