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 = (struct dccp_hdr *)(skb->data + offset);
  74         struct dccp_sock *dp;
  75         struct ipv6_pinfo *np;
  76         struct sock *sk;
  77         int err;
  78         __u64 seq;
  79         struct net *net = dev_net(skb->dev);
  80
  81         if (skb->len < offset + sizeof(*dh) ||
  82             skb->len < offset + __dccp_basic_hdr_len(dh)) {
  83                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
  84                                    ICMP6_MIB_INERRORS);
  85                 return;
  86         }
  87
  88         sk = __inet6_lookup_established(net, &dccp_hashinfo,
  89                                         &hdr->daddr, dh->dccph_dport,
  90                                         &hdr->saddr, ntohs(dh->dccph_sport),
  91                                         inet6_iif(skb));
  92
  93         if (!sk) {
  94                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
  95                                    ICMP6_MIB_INERRORS);
  96                 return;
  97         }
  98
  99         if (sk->sk_state == DCCP_TIME_WAIT) {
 100                 inet_twsk_put(inet_twsk(sk));
 101                 return;
 102         }
 103         seq = dccp_hdr_seq(dh);
 104         if (sk->sk_state == DCCP_NEW_SYN_RECV)
 105                 return dccp_req_err(sk, seq);
 106
 107         bh_lock_sock(sk);
 108         if (sock_owned_by_user(sk))
 109                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 110
 111         if (sk->sk_state == DCCP_CLOSED)
 112                 goto out;
 113
 114         dp = dccp_sk(sk);
 115         if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
 116             !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
 117                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 118                 goto out;
 119         }
 120
 121         np = inet6_sk(sk);
 122
 123         if (type == NDISC_REDIRECT) {
 124                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 125
 126                 if (dst)
 127                         dst->ops->redirect(dst, sk, skb);
 128                 goto out;
 129         }
 130
 131         if (type == ICMPV6_PKT_TOOBIG) {
 132                 struct dst_entry *dst = NULL;
 133
 134                 if (!ip6_sk_accept_pmtu(sk))
 135                         goto out;
 136
 137                 if (sock_owned_by_user(sk))
 138                         goto out;
 139                 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
 140                         goto out;
 141
 142                 dst = inet6_csk_update_pmtu(sk, ntohl(info));
 143                 if (!dst)
 144                         goto out;
 145
 146                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
 147                         dccp_sync_mss(sk, dst_mtu(dst));
 148                 goto out;
 149         }
 150
 151         icmpv6_err_convert(type, code, &err);
 152
 153         /* Might be for an request_sock */
 154         switch (sk->sk_state) {
 155         case DCCP_REQUESTING:
 156         case DCCP_RESPOND:  /* Cannot happen.
 157                                It can, it SYNs are crossed. --ANK */
 158                 if (!sock_owned_by_user(sk)) {
 159                         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
 160                         sk->sk_err = err;
 161                         /*
 162                          * Wake people up to see the error
 163                          * (see connect in sock.c)
 164                          */
 165                         sk->sk_error_report(sk);
 166                         dccp_done(sk);
 167                 } else
 168                         sk->sk_err_soft = err;
 169                 goto out;
 170         }
 171
 172         if (!sock_owned_by_user(sk) && np->recverr) {
 173                 sk->sk_err = err;
 174                 sk->sk_error_report(sk);
 175         } else
 176                 sk->sk_err_soft = err;
 177
 178 out:
 179         bh_unlock_sock(sk);
 180         sock_put(sk);
 181 }
 182
 183
 184 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
 185 {
 186         struct inet_request_sock *ireq = inet_rsk(req);
 187         struct ipv6_pinfo *np = inet6_sk(sk);
 188         struct sk_buff *skb;
 189         struct in6_addr *final_p, final;
 190         struct flowi6 fl6;
 191         int err = -1;
 192         struct dst_entry *dst;
 193
 194         memset(&fl6, 0, sizeof(fl6));
 195         fl6.flowi6_proto = IPPROTO_DCCP;
 196         fl6.daddr = ireq->ir_v6_rmt_addr;
 197         fl6.saddr = ireq->ir_v6_loc_addr;
 198         fl6.flowlabel = 0;
 199         fl6.flowi6_oif = ireq->ir_iif;
 200         fl6.fl6_dport = ireq->ir_rmt_port;
 201         fl6.fl6_sport = htons(ireq->ir_num);
 202         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 203
 204
 205         final_p = fl6_update_dst(&fl6, np->opt, &final);
 206
 207         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 208         if (IS_ERR(dst)) {
 209                 err = PTR_ERR(dst);
 210                 dst = NULL;
 211                 goto done;
 212         }
 213
 214         skb = dccp_make_response(sk, dst, req);
 215         if (skb != NULL) {
 216                 struct dccp_hdr *dh = dccp_hdr(skb);
 217
 218                 dh->dccph_checksum = dccp_v6_csum_finish(skb,
 219                                                          &ireq->ir_v6_loc_addr,
 220                                                          &ireq->ir_v6_rmt_addr);
 221                 fl6.daddr = ireq->ir_v6_rmt_addr;
 222                 err = ip6_xmit(sk, skb, &fl6, np->opt, np->tclass);
 223                 err = net_xmit_eval(err);
 224         }
 225
 226 done:
 227         dst_release(dst);
 228         return err;
 229 }
 230
 231 static void dccp_v6_reqsk_destructor(struct request_sock *req)
 232 {
 233         dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
 234         kfree_skb(inet_rsk(req)->pktopts);
 235 }
 236
 237 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
 238 {
 239         const struct ipv6hdr *rxip6h;
 240         struct sk_buff *skb;
 241         struct flowi6 fl6;
 242         struct net *net = dev_net(skb_dst(rxskb)->dev);
 243         struct sock *ctl_sk = net->dccp.v6_ctl_sk;
 244         struct dst_entry *dst;
 245
 246         if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
 247                 return;
 248
 249         if (!ipv6_unicast_destination(rxskb))
 250                 return;
 251
 252         skb = dccp_ctl_make_reset(ctl_sk, rxskb);
 253         if (skb == NULL)
 254                 return;
 255
 256         rxip6h = ipv6_hdr(rxskb);
 257         dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
 258                                                             &rxip6h->daddr);
 259
 260         memset(&fl6, 0, sizeof(fl6));
 261         fl6.daddr = rxip6h->saddr;
 262         fl6.saddr = rxip6h->daddr;
 263
 264         fl6.flowi6_proto = IPPROTO_DCCP;
 265         fl6.flowi6_oif = inet6_iif(rxskb);
 266         fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
 267         fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
 268         security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));
 269
 270         /* sk = NULL, but it is safe for now. RST socket required. */
 271         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 272         if (!IS_ERR(dst)) {
 273                 skb_dst_set(skb, dst);
 274                 ip6_xmit(ctl_sk, skb, &fl6, NULL, 0);
 275                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
 276                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
 277                 return;
 278         }
 279
 280         kfree_skb(skb);
 281 }
 282
 283 static struct request_sock_ops dccp6_request_sock_ops = {
 284         .family         = AF_INET6,
 285         .obj_size       = sizeof(struct dccp6_request_sock),
 286         .rtx_syn_ack    = dccp_v6_send_response,
 287         .send_ack       = dccp_reqsk_send_ack,
 288         .destructor     = dccp_v6_reqsk_destructor,
 289         .send_reset     = dccp_v6_ctl_send_reset,
 290         .syn_ack_timeout = dccp_syn_ack_timeout,
 291 };
 292
 293 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 294 {
 295         struct request_sock *req;
 296         struct dccp_request_sock *dreq;
 297         struct inet_request_sock *ireq;
 298         struct ipv6_pinfo *np = inet6_sk(sk);
 299         const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
 300         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 301
 302         if (skb->protocol == htons(ETH_P_IP))
 303                 return dccp_v4_conn_request(sk, skb);
 304
 305         if (!ipv6_unicast_destination(skb))
 306                 return 0;       /* discard, don't send a reset here */
 307
 308         if (dccp_bad_service_code(sk, service)) {
 309                 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
 310                 goto drop;
 311         }
 312         /*
 313          * There are no SYN attacks on IPv6, yet...
 314          */
 315         dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
 316         if (inet_csk_reqsk_queue_is_full(sk))
 317                 goto drop;
 318
 319         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
 320                 goto drop;
 321
 322         req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
 323         if (req == NULL)
 324                 goto drop;
 325
 326         if (dccp_reqsk_init(req, dccp_sk(sk), skb))
 327                 goto drop_and_free;
 328
 329         dreq = dccp_rsk(req);
 330         if (dccp_parse_options(sk, dreq, skb))
 331                 goto drop_and_free;
 332
 333         if (security_inet_conn_request(sk, skb, req))
 334                 goto drop_and_free;
 335
 336         ireq = inet_rsk(req);
 337         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 338         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 339         ireq->ireq_family = AF_INET6;
 340
 341         if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
 342             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
 343             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
 344                 atomic_inc(&skb->users);
 345                 ireq->pktopts = skb;
 346         }
 347         ireq->ir_iif = sk->sk_bound_dev_if;
 348
 349         /* So that link locals have meaning */
 350         if (!sk->sk_bound_dev_if &&
 351             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 352                 ireq->ir_iif = inet6_iif(skb);
 353
 354         /*
 355          * Step 3: Process LISTEN state
 356          *
 357          *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
 358          *
 359          * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
 360          */
 361         dreq->dreq_isr     = dcb->dccpd_seq;
 362         dreq->dreq_gsr     = dreq->dreq_isr;
 363         dreq->dreq_iss     = dccp_v6_init_sequence(skb);
 364         dreq->dreq_gss     = dreq->dreq_iss;
 365         dreq->dreq_service = service;
 366
 367         if (dccp_v6_send_response(sk, req))
 368                 goto drop_and_free;
 369
 370         inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
 371         return 0;
 372
 373 drop_and_free:
 374         reqsk_free(req);
 375 drop:
 376         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
 377         return -1;
 378 }
 379
 380 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
 381                                               struct sk_buff *skb,
 382                                               struct request_sock *req,
 383                                               struct dst_entry *dst,
 384                                               struct request_sock *req_unhash,
 385                                               bool *own_req)
 386 {
 387         struct inet_request_sock *ireq = inet_rsk(req);
 388         struct ipv6_pinfo *newnp;
 389         const struct ipv6_pinfo *np = inet6_sk(sk);
 390         struct inet_sock *newinet;
 391         struct dccp6_sock *newdp6;
 392         struct sock *newsk;
 393
 394         if (skb->protocol == htons(ETH_P_IP)) {
 395                 /*
 396                  *      v6 mapped
 397                  */
 398                 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
 399                                                   req_unhash, own_req);
 400                 if (newsk == NULL)
 401                         return NULL;
 402
 403                 newdp6 = (struct dccp6_sock *)newsk;
 404                 newinet = inet_sk(newsk);
 405                 newinet->pinet6 = &newdp6->inet6;
 406                 newnp = inet6_sk(newsk);
 407
 408                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 409
 410                 newnp->saddr = newsk->sk_v6_rcv_saddr;
 411
 412                 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
 413                 newsk->sk_backlog_rcv = dccp_v4_do_rcv;
 414                 newnp->pktoptions  = NULL;
 415                 newnp->opt         = NULL;
 416                 newnp->mcast_oif   = inet6_iif(skb);
 417                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
 418
 419                 /*
 420                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
 421                  * here, dccp_create_openreq_child now does this for us, see the comment in
 422                  * that function for the gory details. -acme
 423                  */
 424
 425                 /* It is tricky place. Until this moment IPv4 tcp
 426                    worked with IPv6 icsk.icsk_af_ops.
 427                    Sync it now.
 428                  */
 429                 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
 430
 431                 return newsk;
 432         }
 433
 434
 435         if (sk_acceptq_is_full(sk))
 436                 goto out_overflow;
 437
 438         if (!dst) {
 439                 struct flowi6 fl6;
 440
 441                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
 442                 if (!dst)
 443                         goto out;
 444         }
 445
 446         newsk = dccp_create_openreq_child(sk, req, skb);
 447         if (newsk == NULL)
 448                 goto out_nonewsk;
 449
 450         /*
 451          * No need to charge this sock to the relevant IPv6 refcnt debug socks
 452          * count here, dccp_create_openreq_child now does this for us, see the
 453          * comment in that function for the gory details. -acme
 454          */
 455
 456         __ip6_dst_store(newsk, dst, NULL, NULL);
 457         newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
 458                                                       NETIF_F_TSO);
 459         newdp6 = (struct dccp6_sock *)newsk;
 460         newinet = inet_sk(newsk);
 461         newinet->pinet6 = &newdp6->inet6;
 462         newnp = inet6_sk(newsk);
 463
 464         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 465
 466         newsk->sk_v6_daddr      = ireq->ir_v6_rmt_addr;
 467         newnp->saddr            = ireq->ir_v6_loc_addr;
 468         newsk->sk_v6_rcv_saddr  = ireq->ir_v6_loc_addr;
 469         newsk->sk_bound_dev_if  = ireq->ir_iif;
 470
 471         /* Now IPv6 options...
 472
 473            First: no IPv4 options.
 474          */
 475         newinet->inet_opt = NULL;
 476
 477         /* Clone RX bits */
 478         newnp->rxopt.all = np->rxopt.all;
 479
 480         newnp->pktoptions = NULL;
 481         newnp->opt        = NULL;
 482         newnp->mcast_oif  = inet6_iif(skb);
 483         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
 484
 485         /*
 486          * Clone native IPv6 options from listening socket (if any)
 487          *
 488          * Yes, keeping reference count would be much more clever, but we make
 489          * one more one thing there: reattach optmem to newsk.
 490          */
 491         if (np->opt != NULL)
 492                 newnp->opt = ipv6_dup_options(newsk, np->opt);
 493
 494         inet_csk(newsk)->icsk_ext_hdr_len = 0;
 495         if (newnp->opt != NULL)
 496                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
 497                                                      newnp->opt->opt_flen);
 498
 499         dccp_sync_mss(newsk, dst_mtu(dst));
 500
 501         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
 502         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 503
 504         if (__inet_inherit_port(sk, newsk) < 0) {
 505                 inet_csk_prepare_forced_close(newsk);
 506                 dccp_done(newsk);
 507                 goto out;
 508         }
 509         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
 510         /* Clone pktoptions received with SYN, if we own the req */
 511         if (*own_req && ireq->pktopts) {
 512                 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
 513                 consume_skb(ireq->pktopts);
 514                 ireq->pktopts = NULL;
 515                 if (newnp->pktoptions)
 516                         skb_set_owner_r(newnp->pktoptions, newsk);
 517         }
 518
 519         return newsk;
 520
 521 out_overflow:
 522         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
 523 out_nonewsk:
 524         dst_release(dst);
 525 out:
 526         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 527         return NULL;
 528 }
 529
 530 /* The socket must have it's spinlock held when we get
 531  * here.
 532  *
 533  * We have a potential double-lock case here, so even when
 534  * doing backlog processing we use the BH locking scheme.
 535  * This is because we cannot sleep with the original spinlock
 536  * held.
 537  */
 538 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 539 {
 540         struct ipv6_pinfo *np = inet6_sk(sk);
 541         struct sk_buff *opt_skb = NULL;
 542
 543         /* Imagine: socket is IPv6. IPv4 packet arrives,
 544            goes to IPv4 receive handler and backlogged.
 545            From backlog it always goes here. Kerboom...
 546            Fortunately, dccp_rcv_established and rcv_established
 547            handle them correctly, but it is not case with
 548            dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
 549          */
 550
 551         if (skb->protocol == htons(ETH_P_IP))
 552                 return dccp_v4_do_rcv(sk, skb);
 553
 554         if (sk_filter(sk, skb))
 555                 goto discard;
 556
 557         /*
 558          * socket locking is here for SMP purposes as backlog rcv is currently
 559          * called with bh processing disabled.
 560          */
 561
 562         /* Do Stevens' IPV6_PKTOPTIONS.
 563
 564            Yes, guys, it is the only place in our code, where we
 565            may make it not affecting IPv4.
 566            The rest of code is protocol independent,
 567            and I do not like idea to uglify IPv4.
 568
 569            Actually, all the idea behind IPV6_PKTOPTIONS
 570            looks not very well thought. For now we latch
 571            options, received in the last packet, enqueued
 572            by tcp. Feel free to propose better solution.
 573                                                --ANK (980728)
 574          */
 575         if (np->rxopt.all)
 576         /*
 577          * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
 578          *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
 579          */
 580                 opt_skb = skb_clone(skb, GFP_ATOMIC);
 581
 582         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
 583                 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
 584                         goto reset;
 585                 if (opt_skb) {
 586                         /* XXX This is where we would goto ipv6_pktoptions. */
 587                         __kfree_skb(opt_skb);
 588                 }
 589                 return 0;
 590         }
 591
 592         /*
 593          *  Step 3: Process LISTEN state
 594          *     If S.state == LISTEN,
 595          *       If P.type == Request or P contains a valid Init Cookie option,
 596          *            (* Must scan the packet's options to check for Init
 597          *               Cookies.  Only Init Cookies are processed here,
 598          *               however; other options are processed in Step 8.  This
 599          *               scan need only be performed if the endpoint uses Init
 600          *               Cookies *)
 601          *            (* Generate a new socket and switch to that socket *)
 602          *            Set S := new socket for this port pair
 603          *            S.state = RESPOND
 604          *            Choose S.ISS (initial seqno) or set from Init Cookies
 605          *            Initialize S.GAR := S.ISS
 606          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
 607          *            Continue with S.state == RESPOND
 608          *            (* A Response packet will be generated in Step 11 *)
 609          *       Otherwise,
 610          *            Generate Reset(No Connection) unless P.type == Reset
 611          *            Drop packet and return
 612          *
 613          * NOTE: the check for the packet types is done in
 614          *       dccp_rcv_state_process
 615          */
 616
 617         if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
 618                 goto reset;
 619         if (opt_skb) {
 620                 /* XXX This is where we would goto ipv6_pktoptions. */
 621                 __kfree_skb(opt_skb);
 622         }
 623         return 0;
 624
 625 reset:
 626         dccp_v6_ctl_send_reset(sk, skb);
 627 discard:
 628         if (opt_skb != NULL)
 629                 __kfree_skb(opt_skb);
 630         kfree_skb(skb);
 631         return 0;
 632 }
 633
 634 static int dccp_v6_rcv(struct sk_buff *skb)
 635 {
 636         const struct dccp_hdr *dh;
 637         struct sock *sk;
 638         int min_cov;
 639
 640         /* Step 1: Check header basics */
 641
 642         if (dccp_invalid_packet(skb))
 643                 goto discard_it;
 644
 645         /* Step 1: If header checksum is incorrect, drop packet and return. */
 646         if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
 647                                      &ipv6_hdr(skb)->daddr)) {
 648                 DCCP_WARN("dropped packet with invalid checksum\n");
 649                 goto discard_it;
 650         }
 651
 652         dh = dccp_hdr(skb);
 653
 654         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
 655         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
 656
 657         if (dccp_packet_without_ack(skb))
 658                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
 659         else
 660                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
 661
 662 lookup:
 663         sk = __inet6_lookup_skb(&dccp_hashinfo, skb,
 664                                 dh->dccph_sport, dh->dccph_dport,
 665                                 inet6_iif(skb));
 666         if (!sk) {
 667                 dccp_pr_debug("failed to look up flow ID in table and "
 668                               "get corresponding socket\n");
 669                 goto no_dccp_socket;
 670         }
 671
 672         /*
 673          * Step 2:
 674          *      ... or S.state == TIMEWAIT,
 675          *              Generate Reset(No Connection) unless P.type == Reset
 676          *              Drop packet and return
 677          */
 678         if (sk->sk_state == DCCP_TIME_WAIT) {
 679                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
 680                 inet_twsk_put(inet_twsk(sk));
 681                 goto no_dccp_socket;
 682         }
 683
 684         if (sk->sk_state == DCCP_NEW_SYN_RECV) {
 685                 struct request_sock *req = inet_reqsk(sk);
 686                 struct sock *nsk = NULL;
 687
 688                 sk = req->rsk_listener;
 689                 if (likely(sk->sk_state == DCCP_LISTEN)) {
 690                         nsk = dccp_check_req(sk, skb, req);
 691                 } else {
 692                         inet_csk_reqsk_queue_drop_and_put(sk, req);
 693                         goto lookup;
 694                 }
 695                 if (!nsk) {
 696                         reqsk_put(req);
 697                         goto discard_it;
 698                 }
 699                 if (nsk == sk) {
 700                         sock_hold(sk);
 701                         reqsk_put(req);
 702                 } else if (dccp_child_process(sk, nsk, skb)) {
 703                         dccp_v6_ctl_send_reset(sk, skb);
 704                         goto discard_it;
 705                 } else {
 706                         return 0;
 707                 }
 708         }
 709         /*
 710          * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
 711          *      o if MinCsCov = 0, only packets with CsCov = 0 are accepted
 712          *      o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
 713          */
 714         min_cov = dccp_sk(sk)->dccps_pcrlen;
 715         if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
 716                 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
 717                               dh->dccph_cscov, min_cov);
 718                 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
 719                 goto discard_and_relse;
 720         }
 721
 722         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 723                 goto discard_and_relse;
 724
 725         return sk_receive_skb(sk, skb, 1) ? -1 : 0;
 726
 727 no_dccp_socket:
 728         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 729                 goto discard_it;
 730         /*
 731          * Step 2:
 732          *      If no socket ...
 733          *              Generate Reset(No Connection) unless P.type == Reset
 734          *              Drop packet and return
 735          */
 736         if (dh->dccph_type != DCCP_PKT_RESET) {
 737                 DCCP_SKB_CB(skb)->dccpd_reset_code =
 738                                         DCCP_RESET_CODE_NO_CONNECTION;
 739                 dccp_v6_ctl_send_reset(sk, skb);
 740         }
 741
 742 discard_it:
 743         kfree_skb(skb);
 744         return 0;
 745
 746 discard_and_relse:
 747         sock_put(sk);
 748         goto discard_it;
 749 }
 750
 751 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 752                            int addr_len)
 753 {
 754         struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
 755         struct inet_connection_sock *icsk = inet_csk(sk);
 756         struct inet_sock *inet = inet_sk(sk);
 757         struct ipv6_pinfo *np = inet6_sk(sk);
 758         struct dccp_sock *dp = dccp_sk(sk);
 759         struct in6_addr *saddr = NULL, *final_p, final;
 760         struct flowi6 fl6;
 761         struct dst_entry *dst;
 762         int addr_type;
 763         int err;
 764
 765         dp->dccps_role = DCCP_ROLE_CLIENT;
 766
 767         if (addr_len < SIN6_LEN_RFC2133)
 768                 return -EINVAL;
 769
 770         if (usin->sin6_family != AF_INET6)
 771                 return -EAFNOSUPPORT;
 772
 773         memset(&fl6, 0, sizeof(fl6));
 774
 775         if (np->sndflow) {
 776                 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
 777                 IP6_ECN_flow_init(fl6.flowlabel);
 778                 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
 779                         struct ip6_flowlabel *flowlabel;
 780                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 781                         if (flowlabel == NULL)
 782                                 return -EINVAL;
 783                         fl6_sock_release(flowlabel);
 784                 }
 785         }
 786         /*
 787          * connect() to INADDR_ANY means loopback (BSD'ism).
 788          */
 789         if (ipv6_addr_any(&usin->sin6_addr))
 790                 usin->sin6_addr.s6_addr[15] = 1;
 791
 792         addr_type = ipv6_addr_type(&usin->sin6_addr);
 793
 794         if (addr_type & IPV6_ADDR_MULTICAST)
 795                 return -ENETUNREACH;
 796
 797         if (addr_type & IPV6_ADDR_LINKLOCAL) {
 798                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 799                     usin->sin6_scope_id) {
 800                         /* If interface is set while binding, indices
 801                          * must coincide.
 802                          */
 803                         if (sk->sk_bound_dev_if &&
 804                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 805                                 return -EINVAL;
 806
 807                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 808                 }
 809
 810                 /* Connect to link-local address requires an interface */
 811                 if (!sk->sk_bound_dev_if)
 812                         return -EINVAL;
 813         }
 814
 815         sk->sk_v6_daddr = usin->sin6_addr;
 816         np->flow_label = fl6.flowlabel;
 817
 818         /*
 819          * DCCP over IPv4
 820          */
 821         if (addr_type == IPV6_ADDR_MAPPED) {
 822                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 823                 struct sockaddr_in sin;
 824
 825                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 826
 827                 if (__ipv6_only_sock(sk))
 828                         return -ENETUNREACH;
 829
 830                 sin.sin_family = AF_INET;
 831                 sin.sin_port = usin->sin6_port;
 832                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 833
 834                 icsk->icsk_af_ops = &dccp_ipv6_mapped;
 835                 sk->sk_backlog_rcv = dccp_v4_do_rcv;
 836
 837                 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 838                 if (err) {
 839                         icsk->icsk_ext_hdr_len = exthdrlen;
 840                         icsk->icsk_af_ops = &dccp_ipv6_af_ops;
 841                         sk->sk_backlog_rcv = dccp_v6_do_rcv;
 842                         goto failure;
 843                 }
 844                 np->saddr = sk->sk_v6_rcv_saddr;
 845                 return err;
 846         }
 847
 848         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 849                 saddr = &sk->sk_v6_rcv_saddr;
 850
 851         fl6.flowi6_proto = IPPROTO_DCCP;
 852         fl6.daddr = sk->sk_v6_daddr;
 853         fl6.saddr = saddr ? *saddr : np->saddr;
 854         fl6.flowi6_oif = sk->sk_bound_dev_if;
 855         fl6.fl6_dport = usin->sin6_port;
 856         fl6.fl6_sport = inet->inet_sport;
 857         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 858
 859         final_p = fl6_update_dst(&fl6, np->opt, &final);
 860
 861         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 862         if (IS_ERR(dst)) {
 863                 err = PTR_ERR(dst);
 864                 goto failure;
 865         }
 866
 867         if (saddr == NULL) {
 868                 saddr = &fl6.saddr;
 869                 sk->sk_v6_rcv_saddr = *saddr;
 870         }
 871
 872         /* set the source address */
 873         np->saddr = *saddr;
 874         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 875
 876         __ip6_dst_store(sk, dst, NULL, NULL);
 877
 878         icsk->icsk_ext_hdr_len = 0;
 879         if (np->opt != NULL)
 880                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
 881                                           np->opt->opt_nflen);
 882
 883         inet->inet_dport = usin->sin6_port;
 884
 885         dccp_set_state(sk, DCCP_REQUESTING);
 886         err = inet6_hash_connect(&dccp_death_row, sk);
 887         if (err)
 888                 goto late_failure;
 889
 890         dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
 891                                                       sk->sk_v6_daddr.s6_addr32,
 892                                                       inet->inet_sport,
 893                                                       inet->inet_dport);
 894         err = dccp_connect(sk);
 895         if (err)
 896                 goto late_failure;
 897
 898         return 0;
 899
 900 late_failure:
 901         dccp_set_state(sk, DCCP_CLOSED);
 902         __sk_dst_reset(sk);
 903 failure:
 904         inet->inet_dport = 0;
 905         sk->sk_route_caps = 0;
 906         return err;
 907 }
 908
 909 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
 910         .queue_xmit        = inet6_csk_xmit,
 911         .send_check        = dccp_v6_send_check,
 912         .rebuild_header    = inet6_sk_rebuild_header,
 913         .conn_request      = dccp_v6_conn_request,
 914         .syn_recv_sock     = dccp_v6_request_recv_sock,
 915         .net_header_len    = sizeof(struct ipv6hdr),
 916         .setsockopt        = ipv6_setsockopt,
 917         .getsockopt        = ipv6_getsockopt,
 918         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 919         .sockaddr_len      = sizeof(struct sockaddr_in6),
 920         .bind_conflict     = inet6_csk_bind_conflict,
 921 #ifdef CONFIG_COMPAT
 922         .compat_setsockopt = compat_ipv6_setsockopt,
 923         .compat_getsockopt = compat_ipv6_getsockopt,
 924 #endif
 925 };
 926
 927 /*
 928  *      DCCP over IPv4 via INET6 API
 929  */
 930 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
 931         .queue_xmit        = ip_queue_xmit,
 932         .send_check        = dccp_v4_send_check,
 933         .rebuild_header    = inet_sk_rebuild_header,
 934         .conn_request      = dccp_v6_conn_request,
 935         .syn_recv_sock     = dccp_v6_request_recv_sock,
 936         .net_header_len    = sizeof(struct iphdr),
 937         .setsockopt        = ipv6_setsockopt,
 938         .getsockopt        = ipv6_getsockopt,
 939         .addr2sockaddr     = inet6_csk_addr2sockaddr,
 940         .sockaddr_len      = sizeof(struct sockaddr_in6),
 941 #ifdef CONFIG_COMPAT
 942         .compat_setsockopt = compat_ipv6_setsockopt,
 943         .compat_getsockopt = compat_ipv6_getsockopt,
 944 #endif
 945 };
 946
 947 /* NOTE: A lot of things set to zero explicitly by call to
 948  *       sk_alloc() so need not be done here.
 949  */
 950 static int dccp_v6_init_sock(struct sock *sk)
 951 {
 952         static __u8 dccp_v6_ctl_sock_initialized;
 953         int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
 954
 955         if (err == 0) {
 956                 if (unlikely(!dccp_v6_ctl_sock_initialized))
 957                         dccp_v6_ctl_sock_initialized = 1;
 958                 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
 959         }
 960
 961         return err;
 962 }
 963
 964 static void dccp_v6_destroy_sock(struct sock *sk)
 965 {
 966         dccp_destroy_sock(sk);
 967         inet6_destroy_sock(sk);
 968 }
 969
 970 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
 971         .twsk_obj_size  = sizeof(struct dccp6_timewait_sock),
 972 };
 973
 974 static struct proto dccp_v6_prot = {
 975         .name              = "DCCPv6",
 976         .owner             = THIS_MODULE,
 977         .close             = dccp_close,
 978         .connect           = dccp_v6_connect,
 979         .disconnect        = dccp_disconnect,
 980         .ioctl             = dccp_ioctl,
 981         .init              = dccp_v6_init_sock,
 982         .setsockopt        = dccp_setsockopt,
 983         .getsockopt        = dccp_getsockopt,
 984         .sendmsg           = dccp_sendmsg,
 985         .recvmsg           = dccp_recvmsg,
 986         .backlog_rcv       = dccp_v6_do_rcv,
 987         .hash              = inet_hash,
 988         .unhash            = inet_unhash,
 989         .accept            = inet_csk_accept,
 990         .get_port          = inet_csk_get_port,
 991         .shutdown          = dccp_shutdown,
 992         .destroy           = dccp_v6_destroy_sock,
 993         .orphan_count      = &dccp_orphan_count,
 994         .max_header        = MAX_DCCP_HEADER,
 995         .obj_size          = sizeof(struct dccp6_sock),
 996         .slab_flags        = SLAB_DESTROY_BY_RCU,
 997         .rsk_prot          = &dccp6_request_sock_ops,
 998         .twsk_prot         = &dccp6_timewait_sock_ops,
 999         .h.hashinfo        = &dccp_hashinfo,
1000 #ifdef CONFIG_COMPAT
1001         .compat_setsockopt = compat_dccp_setsockopt,
1002         .compat_getsockopt = compat_dccp_getsockopt,
1003 #endif
1004 };
1005
1006 static const struct inet6_protocol dccp_v6_protocol = {
1007         .handler        = dccp_v6_rcv,
1008         .err_handler    = dccp_v6_err,
1009         .flags          = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1010 };
1011
1012 static const struct proto_ops inet6_dccp_ops = {
1013         .family            = PF_INET6,
1014         .owner             = THIS_MODULE,
1015         .release           = inet6_release,
1016         .bind              = inet6_bind,
1017         .connect           = inet_stream_connect,
1018         .socketpair        = sock_no_socketpair,
1019         .accept            = inet_accept,
1020         .getname           = inet6_getname,
1021         .poll              = dccp_poll,
1022         .ioctl             = inet6_ioctl,
1023         .listen            = inet_dccp_listen,
1024         .shutdown          = inet_shutdown,
1025         .setsockopt        = sock_common_setsockopt,
1026         .getsockopt        = sock_common_getsockopt,
1027         .sendmsg           = inet_sendmsg,
1028         .recvmsg           = sock_common_recvmsg,
1029         .mmap              = sock_no_mmap,
1030         .sendpage          = sock_no_sendpage,
1031 #ifdef CONFIG_COMPAT
1032         .compat_setsockopt = compat_sock_common_setsockopt,
1033         .compat_getsockopt = compat_sock_common_getsockopt,
1034 #endif
1035 };
1036
1037 static struct inet_protosw dccp_v6_protosw = {
1038         .type           = SOCK_DCCP,
1039         .protocol       = IPPROTO_DCCP,
1040         .prot           = &dccp_v6_prot,
1041         .ops            = &inet6_dccp_ops,
1042         .flags          = INET_PROTOSW_ICSK,
1043 };
1044
1045 static int __net_init dccp_v6_init_net(struct net *net)
1046 {
1047         if (dccp_hashinfo.bhash == NULL)
1048                 return -ESOCKTNOSUPPORT;
1049
1050         return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
1051                                     SOCK_DCCP, IPPROTO_DCCP, net);
1052 }
1053
1054 static void __net_exit dccp_v6_exit_net(struct net *net)
1055 {
1056         inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
1057 }
1058
1059 static struct pernet_operations dccp_v6_ops = {
1060         .init   = dccp_v6_init_net,
1061         .exit   = dccp_v6_exit_net,
1062 };
1063
1064 static int __init dccp_v6_init(void)
1065 {
1066         int err = proto_register(&dccp_v6_prot, 1);
1067
1068         if (err != 0)
1069                 goto out;
1070
1071         err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1072         if (err != 0)
1073                 goto out_unregister_proto;
1074
1075         inet6_register_protosw(&dccp_v6_protosw);
1076
1077         err = register_pernet_subsys(&dccp_v6_ops);
1078         if (err != 0)
1079                 goto out_destroy_ctl_sock;
1080 out:
1081         return err;
1082
1083 out_destroy_ctl_sock:
1084         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1085         inet6_unregister_protosw(&dccp_v6_protosw);
1086 out_unregister_proto:
1087         proto_unregister(&dccp_v6_prot);
1088         goto out;
1089 }
1090
1091 static void __exit dccp_v6_exit(void)
1092 {
1093         unregister_pernet_subsys(&dccp_v6_ops);
1094         inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
1095         inet6_unregister_protosw(&dccp_v6_protosw);
1096         proto_unregister(&dccp_v6_prot);
1097 }
1098
1099 module_init(dccp_v6_init);
1100 module_exit(dccp_v6_exit);
1101
1102 /*
1103  * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1104  * values directly, Also cover the case where the protocol is not specified,
1105  * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
1106  */
1107 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
1108 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
1109 MODULE_LICENSE("GPL");
1110 MODULE_AUTHOR("Arnaldo Carvalho de Melo <[email protected]>");
1111 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");