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                 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                 refcount_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         reqsk_put(req);
 384         return 0;
 385
 386 drop_and_free:
 387         reqsk_free(req);
 388 drop:
 389         __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
 390         return -1;
 391 }
 392
 393 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
 394                                               struct sk_buff *skb,
 395                                               struct request_sock *req,
 396                                               struct dst_entry *dst,
 397                                               struct request_sock *req_unhash,
 398                                               bool *own_req)
 399 {
 400         struct inet_request_sock *ireq = inet_rsk(req);
 401         struct ipv6_pinfo *newnp;
 402         const struct ipv6_pinfo *np = inet6_sk(sk);
 403         struct ipv6_txoptions *opt;
 404         struct inet_sock *newinet;
 405         struct dccp6_sock *newdp6;
 406         struct sock *newsk;
 407
 408         if (skb->protocol == htons(ETH_P_IP)) {
 409                 /*
 410                  *      v6 mapped
 411                  */
 412                 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
 413                                                   req_unhash, own_req);
 414                 if (newsk == NULL)
 415                         return NULL;
 416
 417                 newdp6 = (struct dccp6_sock *)newsk;
 418                 newinet = inet_sk(newsk);
 419                 newinet->pinet6 = &newdp6->inet6;
 420                 newnp = inet6_sk(newsk);
 421
 422                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 423
 424                 newnp->saddr = newsk->sk_v6_rcv_saddr;
 425
 426                 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
 427                 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
 428                 newnp->pktoptions  = NULL;
 429                 newnp->opt         = NULL;
 430                 newnp->ipv6_mc_list = NULL;
 431                 newnp->ipv6_ac_list = NULL;
 432                 newnp->ipv6_fl_list = NULL;
 433                 newnp->mcast_oif   = inet6_iif(skb);
 434                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
 435
 436                 /*
 437                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
 438                  * here, dccp_create_openreq_child now does this for us, see the comment in
 439                  * that function for the gory details. -acme
 440                  */
 441
 442                 /* It is tricky place. Until this moment IPv4 tcp
 443                    worked with IPv6 icsk.icsk_af_ops.
 444                    Sync it now.
 445                  */
 446                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
 447
 448                 return newsk;
 449         }
 450
 451
 452         if (sk_acceptq_is_full(sk))
 453                 goto out_overflow;
 454
 455         if (!dst) {
 456                 struct flowi6 fl6;
 457
 458                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
 459                 if (!dst)
 460                         goto out;
 461         }
 462
 463         newsk = dccp_create_openreq_child(sk, req, skb);
 464         if (newsk == NULL)
 465                 goto out_nonewsk;
 466
 467         /*
 468          * No need to charge this sock to the relevant IPv6 refcnt debug socks
 469          * count here, dccp_create_openreq_child now does this for us, see the
 470          * comment in that function for the gory details. -acme
 471          */
 472
 473         ip6_dst_store(newsk, dst, NULL, NULL);
 474         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
 475                                                       NETIF_F_TSO);
 476         newdp6 = (struct dccp6_sock *)newsk;
 477         newinet = inet_sk(newsk);
 478         newinet->pinet6 = &newdp6->inet6;
 479         newnp = inet6_sk(newsk);
 480
 481         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 482
 483         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
 484         newnp->saddr            = ireq->ir_v6_loc_addr;
 485         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
 486         newsk->sk_bound_dev_if  = ireq->ir_iif;
 487
 488         /* Now IPv6 options...
 489
 490            First: no IPv4 options.
 491          */
 492         newinet->inet_opt = NULL;
 493
 494         /* Clone RX bits */
 495         newnp->rxopt.all = np->rxopt.all;
 496
 497         newnp->ipv6_mc_list = NULL;
 498         newnp->ipv6_ac_list = NULL;
 499         newnp->ipv6_fl_list = NULL;
 500         newnp->pktoptions = NULL;
 501         newnp->opt        = NULL;
 502         newnp->mcast_oif  = inet6_iif(skb);
 503         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
 504
 505         /*
 506          * Clone native IPv6 options from listening socket (if any)
 507          *
 508          * Yes, keeping reference count would be much more clever, but we make
 509          * one more one thing there: reattach optmem to newsk.
 510          */
 511         opt = ireq->ipv6_opt;
 512         if (!opt)
 513                 opt = rcu_dereference(np->opt);
 514         if (opt) {
 515                 opt = ipv6_dup_options(newsk, opt);
 516                 RCU_INIT_POINTER(newnp->opt, opt);
 517         }
 518         inet_csk(newsk)->icsk_ext_hdr_len = 0;
 519         if (opt)
 520                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
 521                                                     opt->opt_flen;
 522
 523         dccp_sync_mss(newsk, dst_mtu(dst));
 524
 525         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
 526         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 527
 528         if (__inet_inherit_port(sk, newsk) < 0) {
 529                 inet_csk_prepare_forced_close(newsk);
 530                 dccp_done(newsk);
 531                 goto out;
 532         }
 533         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
 534         /* Clone pktoptions received with SYN, if we own the req */
 535         if (*own_req && ireq->pktopts) {
 536                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
 537                 consume_skb(ireq->pktopts);
 538                 ireq->pktopts = NULL;
 539                 if (newnp->pktoptions)
 540                         skb_set_owner_r(newnp->pktoptions, newsk);
 541         }
 542
 543         return newsk;
 544
 545 out_overflow:
 546         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
 547 out_nonewsk:
 548         dst_release(dst);
 549 out:
 550         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
 551         return NULL;
 552 }
 553
 554 /* The socket must have it's spinlock held when we get
 555  * here.
 556  *
 557  * We have a potential double-lock case here, so even when
 558  * doing backlog processing we use the BH locking scheme.
 559  * This is because we cannot sleep with the original spinlock
 560  * held.
 561  */
 562 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 563 {
 564         struct ipv6_pinfo *np = inet6_sk(sk);
 565         struct sk_buff *opt_skb = NULL;
 566
 567         /* Imagine: socket is IPv6. IPv4 packet arrives,
 568            goes to IPv4 receive handler and backlogged.
 569            From backlog it always goes here. Kerboom...
 570            Fortunately, dccp_rcv_established and rcv_established
 571            handle them correctly, but it is not case with
 572            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
 573          */
 574
 575         if (skb->protocol == htons(ETH_P_IP))
 576                 return dccp_v4_do_rcv(sk, skb);
 577
 578         if (sk_filter(sk, skb))
 579                 goto discard;
 580
 581         /*
 582          * socket locking is here for SMP purposes as backlog rcv is currently
 583          * called with bh processing disabled.
 584          */
 585
 586         /* Do Stevens' IPV6_PKTOPTIONS.
 587
 588            Yes, guys, it is the only place in our code, where we
 589            may make it not affecting IPv4.
 590            The rest of code is protocol independent,
 591            and I do not like idea to uglify IPv4.
 592
 593            Actually, all the idea behind IPV6_PKTOPTIONS
 594            looks not very well thought. For now we latch
 595            options, received in the last packet, enqueued
 596            by tcp. Feel free to propose better solution.
 597                                                --ANK (980728)
 598          */
 599         if (np->rxopt.all)
 600         /*
 601          * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
 602          *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
 603          */
 604                 opt_skb = skb_clone(skb, GFP_ATOMIC);
 605
 606         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
 607                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
 608                         goto reset;
 609                 if (opt_skb) {
 610                         /* XXX This is where we would goto ipv6_pktoptions. */
 611                         __kfree_skb(opt_skb);
 612                 }
 613                 return 0;
 614         }
 615
 616         /*
 617          *  Step 3: Process LISTEN state
 618          *     If S.state == LISTEN,
 619          *       If P.type == Request or P contains a valid Init Cookie option,
 620          *            (* Must scan the packet's options to check for Init
 621          *               Cookies.  Only Init Cookies are processed here,
 622          *               however; other options are processed in Step 8.  This
 623          *               scan need only be performed if the endpoint uses Init
 624          *               Cookies *)
 625          *            (* Generate a new socket and switch to that socket *)
 626          *            Set S := new socket for this port pair
 627          *            S.state = RESPOND
 628          *            Choose S.ISS (initial seqno) or set from Init Cookies
 629          *            Initialize S.GAR := S.ISS
 630          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
 631          *            Continue with S.state == RESPOND
 632          *            (* A Response packet will be generated in Step 11 *)
 633          *       Otherwise,
 634          *            Generate Reset(No Connection) unless P.type == Reset
 635          *            Drop packet and return
 636          *
 637          * NOTE: the check for the packet types is done in
 638          *       dccp_rcv_state_process
 639          */
 640
 641         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
 642                 goto reset;
 643         if (opt_skb) {
 644                 /* XXX This is where we would goto ipv6_pktoptions. */
 645                 __kfree_skb(opt_skb);
 646         }
 647         return 0;
 648
 649 reset:
 650         dccp_v6_ctl_send_reset(sk, skb);
 651 discard:
 652         if (opt_skb != NULL)
 653                 __kfree_skb(opt_skb);
 654         kfree_skb(skb);
 655         return 0;
 656 }
 657
 658 static int dccp_v6_rcv(struct sk_buff *skb)
 659 {
 660         const struct dccp_hdr *dh;
 661         bool refcounted;
 662         struct sock *sk;
 663         int min_cov;
 664
 665         /* Step 1: Check header basics */
 666
 667         if (dccp_invalid_packet(skb))
 668                 goto discard_it;
 669
 670         /* Step 1: If header checksum is incorrect, drop packet and return. */
 671         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
 672                                      &ipv6_hdr(skb)->daddr)) {
 673                 DCCP_WARN("dropped packet with invalid checksum\n");
 674                 goto discard_it;
 675         }
 676
 677         dh = dccp_hdr(skb);
 678
 679         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
 680         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
 681
 682         if (dccp_packet_without_ack(skb))
 683                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
 684         else
 685                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
 686
 687 lookup:
 688         sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
 689                                 dh->dccph_sport, dh->dccph_dport,
 690                                 inet6_iif(skb), &refcounted);
 691         if (!sk) {
 692                 dccp_pr_debug("failed to look up flow ID in table and "
 693                               "get corresponding socket\n");
 694                 goto no_dccp_socket;
 695         }
 696
 697         /*
 698          * Step 2:
 699          *      ... or S.state == TIMEWAIT,
 700          *              Generate Reset(No Connection) unless P.type == Reset
 701          *              Drop packet and return
 702          */
 703         if (sk->sk_state == DCCP_TIME_WAIT) {
 704                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
 705                 inet_twsk_put(inet_twsk(sk));
 706                 goto no_dccp_socket;
 707         }
 708
 709         if (sk->sk_state == DCCP_NEW_SYN_RECV) {
 710                 struct request_sock *req = inet_reqsk(sk);
 711                 struct sock *nsk;
 712
 713                 sk = req->rsk_listener;
 714                 if (unlikely(sk->sk_state != DCCP_LISTEN)) {
 715                         inet_csk_reqsk_queue_drop_and_put(sk, req);
 716                         goto lookup;
 717                 }
 718                 sock_hold(sk);
 719                 refcounted = true;
 720                 nsk = dccp_check_req(sk, skb, req);
 721                 if (!nsk) {
 722                         reqsk_put(req);
 723                         goto discard_and_relse;
 724                 }
 725                 if (nsk == sk) {
 726                         reqsk_put(req);
 727                 } else if (dccp_child_process(sk, nsk, skb)) {
 728                         dccp_v6_ctl_send_reset(sk, skb);
 729                         goto discard_and_relse;
 730                 } else {
 731                         sock_put(sk);
 732                         return 0;
 733                 }
 734         }
 735         /*
 736          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
 737          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
 738          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
 739          */
 740         min_cov = dccp_sk(sk)->dccps_pcrlen;
 741         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
 742                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
 743                               dh->dccph_cscov, min_cov);
 744                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
 745                 goto discard_and_relse;
 746         }
 747
 748         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 749                 goto discard_and_relse;
 750
 751         return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4,
 752                                 refcounted) ? -1 : 0;
 753
 754 no_dccp_socket:
 755         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 756                 goto discard_it;
 757         /*
 758          * Step 2:
 759          *      If no socket ...
 760          *              Generate Reset(No Connection) unless P.type == Reset
 761          *              Drop packet and return
 762          */
 763         if (dh->dccph_type != DCCP_PKT_RESET) {
 764                 DCCP_SKB_CB(skb)->dccpd_reset_code =
 765                                         DCCP_RESET_CODE_NO_CONNECTION;
 766                 dccp_v6_ctl_send_reset(sk, skb);
 767         }
 768
 769 discard_it:
 770         kfree_skb(skb);
 771         return 0;
 772
 773 discard_and_relse:
 774         if (refcounted)
 775                 sock_put(sk);
 776         goto discard_it;
 777 }
 778
 779 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 780                            int addr_len)
 781 {
 782         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
 783         struct inet_connection_sock *icsk = inet_csk(sk);
 784         struct inet_sock *inet = inet_sk(sk);
 785         struct ipv6_pinfo *np = inet6_sk(sk);
 786         struct dccp_sock *dp = dccp_sk(sk);
 787         struct in6_addr *saddr = NULL, *final_p, final;
 788         struct ipv6_txoptions *opt;
 789         struct flowi6 fl6;
 790         struct dst_entry *dst;
 791         int addr_type;
 792         int err;
 793
 794         dp->dccps_role = DCCP_ROLE_CLIENT;
 795
 796         if (addr_len < SIN6_LEN_RFC2133)
 797                 return -EINVAL;
 798
 799         if (usin->sin6_family != AF_INET6)
 800                 return -EAFNOSUPPORT;
 801
 802         memset(&fl6, 0, sizeof(fl6));
 803
 804         if (np->sndflow) {
 805                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
 806                 IP6_ECN_flow_init(fl6.flowlabel);
 807                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
 808                         struct ip6_flowlabel *flowlabel;
 809                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 810                         if (flowlabel == NULL)
 811                                 return -EINVAL;
 812                         fl6_sock_release(flowlabel);
 813                 }
 814         }
 815         /*
 816          * connect() to INADDR_ANY means loopback (BSD'ism).
 817          */
 818         if (ipv6_addr_any(&usin->sin6_addr))
 819                 usin->sin6_addr.s6_addr[15] = 1;
 820
 821         addr_type = ipv6_addr_type(&usin->sin6_addr);
 822
 823         if (addr_type & IPV6_ADDR_MULTICAST)
 824                 return -ENETUNREACH;
 825
 826         if (addr_type & IPV6_ADDR_LINKLOCAL) {
 827                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 828                     usin->sin6_scope_id) {
 829                         /* If interface is set while binding, indices
 830                          * must coincide.
 831                          */
 832                         if (sk->sk_bound_dev_if &&
 833                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 834                                 return -EINVAL;
 835
 836                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 837                 }
 838
 839                 /* Connect to link-local address requires an interface */
 840                 if (!sk->sk_bound_dev_if)
 841                         return -EINVAL;
 842         }
 843
 844         sk->sk_v6_daddr = usin->sin6_addr;
 845         np->flow_label = fl6.flowlabel;
 846
 847         /*
 848          * DCCP over IPv4
 849          */
 850         if (addr_type == IPV6_ADDR_MAPPED) {
 851                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 852                 struct sockaddr_in sin;
 853
 854                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 855
 856                 if (__ipv6_only_sock(sk))
 857                         return -ENETUNREACH;
 858
 859                 sin.sin_family = AF_INET;
 860                 sin.sin_port = usin->sin6_port;
 861                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 862
 863                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
 864                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
 865
 866                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 867                 if (err) {
 868                         icsk->icsk_ext_hdr_len = exthdrlen;
 869                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
 870                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
 871                         goto failure;
 872                 }
 873                 np->saddr = sk->sk_v6_rcv_saddr;
 874                 return err;
 875         }
 876
 877         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 878                 saddr = &sk->sk_v6_rcv_saddr;
 879
 880         fl6.flowi6_proto = IPPROTO_DCCP;
 881         fl6.daddr = sk->sk_v6_daddr;
 882         fl6.saddr = saddr ? *saddr : np->saddr;
 883         fl6.flowi6_oif = sk->sk_bound_dev_if;
 884         fl6.fl6_dport = usin->sin6_port;
 885         fl6.fl6_sport = inet->inet_sport;
 886         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 887
 888         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 889         final_p = fl6_update_dst(&fl6, opt, &final);
 890
 891         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 892         if (IS_ERR(dst)) {
 893                 err = PTR_ERR(dst);
 894                 goto failure;
 895         }
 896
 897         if (saddr == NULL) {
 898                 saddr = &fl6.saddr;
 899                 sk->sk_v6_rcv_saddr = *saddr;
 900         }
 901
 902         /* set the source address */
 903         np->saddr = *saddr;
 904         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 905
 906         ip6_dst_store(sk, dst, NULL, NULL);
 907
 908         icsk->icsk_ext_hdr_len = 0;
 909         if (opt)
 910                 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
 911
 912         inet->inet_dport = usin->sin6_port;
 913
 914         dccp_set_state(sk, DCCP_REQUESTING);
 915         err = inet6_hash_connect(&dccp_death_row, sk);
 916         if (err)
 917                 goto late_failure;
 918
 919         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
 920                                                       sk->sk_v6_daddr.s6_addr32,
 921                                                       inet->inet_sport,
 922                                                       inet->inet_dport);
 923         err = dccp_connect(sk);
 924         if (err)
 925                 goto late_failure;
 926
 927         return 0;
 928
 929 late_failure:
 930         dccp_set_state(sk, DCCP_CLOSED);
 931         __sk_dst_reset(sk);
 932 failure:
 933         inet->inet_dport = 0;
 934         sk->sk_route_caps = 0;
 935         return err;
 936 }
 937
 938 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
 939         .queue_xmit        = inet6_csk_xmit,
 940         .send_check        = dccp_v6_send_check,
 941         .rebuild_header    = inet6_sk_rebuild_header,
 942         .conn_request      = dccp_v6_conn_request,
 943         .syn_recv_sock     = dccp_v6_request_recv_sock,
 944         .net_header_len    = sizeof(struct ipv6hdr),
 945         .setsockopt        = ipv6_setsockopt,
 946         .getsockopt        = ipv6_getsockopt,
 947         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 948         .sockaddr_len      = sizeof(struct sockaddr_in6),
 949 #ifdef CONFIG_COMPAT
 950         .compat_setsockopt = compat_ipv6_setsockopt,
 951         .compat_getsockopt = compat_ipv6_getsockopt,
 952 #endif
 953 };
 954
 955 /*
 956  *      DCCP over IPv4 via INET6 API
 957  */
 958 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
 959         .queue_xmit        = ip_queue_xmit,
 960         .send_check        = dccp_v4_send_check,
 961         .rebuild_header    = inet_sk_rebuild_header,
 962         .conn_request      = dccp_v6_conn_request,
 963         .syn_recv_sock     = dccp_v6_request_recv_sock,
 964         .net_header_len    = sizeof(struct iphdr),
 965         .setsockopt        = ipv6_setsockopt,
 966         .getsockopt        = ipv6_getsockopt,
 967         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 968         .sockaddr_len      = sizeof(struct sockaddr_in6),
 969 #ifdef CONFIG_COMPAT
 970         .compat_setsockopt = compat_ipv6_setsockopt,
 971         .compat_getsockopt = compat_ipv6_getsockopt,
 972 #endif
 973 };
 974
 975 /* NOTE: A lot of things set to zero explicitly by call to
 976  *       sk_alloc() so need not be done here.
 977  */
 978 static int dccp_v6_init_sock(struct sock *sk)
 979 {
 980         static __u8 dccp_v6_ctl_sock_initialized;
 981         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
 982
 983         if (err == 0) {
 984                 if (unlikely(!dccp_v6_ctl_sock_initialized))
 985                         dccp_v6_ctl_sock_initialized = 1;
 986                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
 987         }
 988
 989         return err;
 990 }
 991
 992 static void dccp_v6_destroy_sock(struct sock *sk)
 993 {
 994         dccp_destroy_sock(sk);
 995         inet6_destroy_sock(sk);
 996 }
 997
 998 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
 999         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
1000 };
1001
1002 static struct proto dccp_v6_prot = {
1003         .name              = "DCCPv6",
1004         .owner             = THIS_MODULE,
1005         .close             = dccp_close,
1006         .connect           = dccp_v6_connect,
1007         .disconnect        = dccp_disconnect,
1008         .ioctl             = dccp_ioctl,
1009         .init              = dccp_v6_init_sock,
1010         .setsockopt        = dccp_setsockopt,
1011         .getsockopt        = dccp_getsockopt,
1012         .sendmsg           = dccp_sendmsg,
1013         .recvmsg           = dccp_recvmsg,
1014         .backlog_rcv       = dccp_v6_do_rcv,
1015         .hash              = inet6_hash,
1016         .unhash            = inet_unhash,
1017         .accept            = inet_csk_accept,
1018         .get_port          = inet_csk_get_port,
1019         .shutdown          = dccp_shutdown,
1020         .destroy           = dccp_v6_destroy_sock,
1021         .orphan_count      = &dccp_orphan_count,
1022         .max_header        = MAX_DCCP_HEADER,
1023         .obj_size          = sizeof(struct dccp6_sock),
1024         .slab_flags        = SLAB_TYPESAFE_BY_RCU,
1025         .rsk_prot          = &dccp6_request_sock_ops,
1026         .twsk_prot         = &dccp6_timewait_sock_ops,
1027         .h.hashinfo        = &dccp_hashinfo,
1028 #ifdef CONFIG_COMPAT
1029         .compat_setsockopt = compat_dccp_setsockopt,
1030         .compat_getsockopt = compat_dccp_getsockopt,
1031 #endif
1032 };
1033
1034 static const struct inet6_protocol dccp_v6_protocol = {
1035         .handler        = dccp_v6_rcv,
1036         .err_handler    = dccp_v6_err,
1037         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1038 };
1039
1040 static const struct proto_ops inet6_dccp_ops = {
1041         .family            = PF_INET6,
1042         .owner             = THIS_MODULE,
1043         .release           = inet6_release,
1044         .bind              = inet6_bind,
1045         .connect           = inet_stream_connect,
1046         .socketpair        = sock_no_socketpair,
1047         .accept            = inet_accept,
1048         .getname           = inet6_getname,
1049         .poll              = dccp_poll,
1050         .ioctl             = inet6_ioctl,
1051         .listen            = inet_dccp_listen,
1052         .shutdown          = inet_shutdown,
1053         .setsockopt        = sock_common_setsockopt,
1054         .getsockopt        = sock_common_getsockopt,
1055         .sendmsg           = inet_sendmsg,
1056         .recvmsg           = sock_common_recvmsg,
1057         .mmap              = sock_no_mmap,
1058         .sendpage          = sock_no_sendpage,
1059 #ifdef CONFIG_COMPAT
1060         .compat_setsockopt = compat_sock_common_setsockopt,
1061         .compat_getsockopt = compat_sock_common_getsockopt,
1062 #endif
1063 };
1064
1065 static struct inet_protosw dccp_v6_protosw = {
1066         .type           = SOCK_DCCP,
1067         .protocol       = IPPROTO_DCCP,
1068         .prot           = &dccp_v6_prot,
1069         .ops            = &inet6_dccp_ops,
1070         .flags          = INET_PROTOSW_ICSK,
1071 };
1072
1073 static int __net_init dccp_v6_init_net(struct net *net)
1074 {
1075         if (dccp_hashinfo.bhash == NULL)
1076                 return -ESOCKTNOSUPPORT;
1077
1078         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1079                                     SOCK_DCCP, IPPROTO_DCCP, net);
1080 }
1081
1082 static void __net_exit dccp_v6_exit_net(struct net *net)
1083 {
1084         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1085 }
1086
1087 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
1088 {
1089         inet_twsk_purge(&dccp_hashinfo, AF_INET6);
1090 }
1091
1092 static struct pernet_operations dccp_v6_ops = {
1093         .init   = dccp_v6_init_net,
1094         .exit   = dccp_v6_exit_net,
1095         .exit_batch = dccp_v6_exit_batch,
1096 };
1097
1098 static int __init dccp_v6_init(void)
1099 {
1100         int err = proto_register(&dccp_v6_prot, 1);
1101
1102         if (err)
1103                 goto out;
1104
1105         inet6_register_protosw(&dccp_v6_protosw);
1106
1107         err = register_pernet_subsys(&dccp_v6_ops);
1108         if (err)
1109                 goto out_destroy_ctl_sock;
1110
1111         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1112         if (err)
1113                 goto out_unregister_proto;
1114
1115 out:
1116         return err;
1117 out_unregister_proto:
1118         unregister_pernet_subsys(&dccp_v6_ops);
1119 out_destroy_ctl_sock:
1120         inet6_unregister_protosw(&dccp_v6_protosw);
1121         proto_unregister(&dccp_v6_prot);
1122         goto out;
1123 }
1124
1125 static void __exit dccp_v6_exit(void)
1126 {
1127         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1128         unregister_pernet_subsys(&dccp_v6_ops);
1129         inet6_unregister_protosw(&dccp_v6_protosw);
1130         proto_unregister(&dccp_v6_prot);
1131 }
1132
1133 module_init(dccp_v6_init);
1134 module_exit(dccp_v6_exit);
1135
1136 /*
1137  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1138  * values directly, Also cover the case where the protocol is not specified,
1139  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1140  */
1141 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1142 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1143 MODULE_LICENSE("GPL");
1144 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1145 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");