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 atomic_inc(&skb->users); 357 ireq->pktopts = skb; 358 } 359 ireq->ir_iif = sk->sk_bound_dev_if; 360 361 /* So that link locals have meaning */ 362 if (!sk->sk_bound_dev_if && 363 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 364 ireq->ir_iif = inet6_iif(skb); 365 366 /* 367 * Step 3: Process LISTEN state 368 * 369 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 370 * 371 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 372 */ 373 dreq->dreq_isr = dcb->dccpd_seq; 374 dreq->dreq_gsr = dreq->dreq_isr; 375 dreq->dreq_iss = dccp_v6_init_sequence(skb); 376 dreq->dreq_gss = dreq->dreq_iss; 377 dreq->dreq_service = service; 378 379 if (dccp_v6_send_response(sk, req)) 380 goto drop_and_free; 381 382 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 383 return 0; 384 385 drop_and_free: 386 reqsk_free(req); 387 drop: 388 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 389 return -1; 390 } 391 392 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 393 struct sk_buff *skb, 394 struct request_sock *req, 395 struct dst_entry *dst, 396 struct request_sock *req_unhash, 397 bool *own_req) 398 { 399 struct inet_request_sock *ireq = inet_rsk(req); 400 struct ipv6_pinfo *newnp; 401 const struct ipv6_pinfo *np = inet6_sk(sk); 402 struct ipv6_txoptions *opt; 403 struct inet_sock *newinet; 404 struct dccp6_sock *newdp6; 405 struct sock *newsk; 406 407 if (skb->protocol == htons(ETH_P_IP)) { 408 /* 409 * v6 mapped 410 */ 411 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 412 req_unhash, own_req); 413 if (newsk == NULL) 414 return NULL; 415 416 newdp6 = (struct dccp6_sock *)newsk; 417 newinet = inet_sk(newsk); 418 newinet->pinet6 = &newdp6->inet6; 419 newnp = inet6_sk(newsk); 420 421 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 422 423 newnp->saddr = newsk->sk_v6_rcv_saddr; 424 425 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 426 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 427 newnp->pktoptions = NULL; 428 newnp->opt = NULL; 429 newnp->mcast_oif = inet6_iif(skb); 430 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 431 432 /* 433 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 434 * here, dccp_create_openreq_child now does this for us, see the comment in 435 * that function for the gory details. -acme 436 */ 437 438 /* It is tricky place. Until this moment IPv4 tcp 439 worked with IPv6 icsk.icsk_af_ops. 440 Sync it now. 441 */ 442 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 443 444 return newsk; 445 } 446 447 448 if (sk_acceptq_is_full(sk)) 449 goto out_overflow; 450 451 if (!dst) { 452 struct flowi6 fl6; 453 454 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 455 if (!dst) 456 goto out; 457 } 458 459 newsk = dccp_create_openreq_child(sk, req, skb); 460 if (newsk == NULL) 461 goto out_nonewsk; 462 463 /* 464 * No need to charge this sock to the relevant IPv6 refcnt debug socks 465 * count here, dccp_create_openreq_child now does this for us, see the 466 * comment in that function for the gory details. -acme 467 */ 468 469 ip6_dst_store(newsk, dst, NULL, NULL); 470 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 471 NETIF_F_TSO); 472 newdp6 = (struct dccp6_sock *)newsk; 473 newinet = inet_sk(newsk); 474 newinet->pinet6 = &newdp6->inet6; 475 newnp = inet6_sk(newsk); 476 477 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 478 479 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 480 newnp->saddr = ireq->ir_v6_loc_addr; 481 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 482 newsk->sk_bound_dev_if = ireq->ir_iif; 483 484 /* Now IPv6 options... 485 486 First: no IPv4 options. 487 */ 488 newinet->inet_opt = NULL; 489 490 /* Clone RX bits */ 491 newnp->rxopt.all = np->rxopt.all; 492 493 newnp->pktoptions = NULL; 494 newnp->opt = NULL; 495 newnp->mcast_oif = inet6_iif(skb); 496 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 497 498 /* 499 * Clone native IPv6 options from listening socket (if any) 500 * 501 * Yes, keeping reference count would be much more clever, but we make 502 * one more one thing there: reattach optmem to newsk. 503 */ 504 opt = ireq->ipv6_opt; 505 if (!opt) 506 opt = rcu_dereference(np->opt); 507 if (opt) { 508 opt = ipv6_dup_options(newsk, opt); 509 RCU_INIT_POINTER(newnp->opt, opt); 510 } 511 inet_csk(newsk)->icsk_ext_hdr_len = 0; 512 if (opt) 513 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 514 opt->opt_flen; 515 516 dccp_sync_mss(newsk, dst_mtu(dst)); 517 518 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 519 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 520 521 if (__inet_inherit_port(sk, newsk) < 0) { 522 inet_csk_prepare_forced_close(newsk); 523 dccp_done(newsk); 524 goto out; 525 } 526 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); 527 /* Clone pktoptions received with SYN, if we own the req */ 528 if (*own_req && ireq->pktopts) { 529 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC); 530 consume_skb(ireq->pktopts); 531 ireq->pktopts = NULL; 532 if (newnp->pktoptions) 533 skb_set_owner_r(newnp->pktoptions, newsk); 534 } 535 536 return newsk; 537 538 out_overflow: 539 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 540 out_nonewsk: 541 dst_release(dst); 542 out: 543 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 544 return NULL; 545 } 546 547 /* The socket must have it's spinlock held when we get 548 * here. 549 * 550 * We have a potential double-lock case here, so even when 551 * doing backlog processing we use the BH locking scheme. 552 * This is because we cannot sleep with the original spinlock 553 * held. 554 */ 555 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 556 { 557 struct ipv6_pinfo *np = inet6_sk(sk); 558 struct sk_buff *opt_skb = NULL; 559 560 /* Imagine: socket is IPv6. IPv4 packet arrives, 561 goes to IPv4 receive handler and backlogged. 562 From backlog it always goes here. Kerboom... 563 Fortunately, dccp_rcv_established and rcv_established 564 handle them correctly, but it is not case with 565 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 566 */ 567 568 if (skb->protocol == htons(ETH_P_IP)) 569 return dccp_v4_do_rcv(sk, skb); 570 571 if (sk_filter(sk, skb)) 572 goto discard; 573 574 /* 575 * socket locking is here for SMP purposes as backlog rcv is currently 576 * called with bh processing disabled. 577 */ 578 579 /* Do Stevens' IPV6_PKTOPTIONS. 580 581 Yes, guys, it is the only place in our code, where we 582 may make it not affecting IPv4. 583 The rest of code is protocol independent, 584 and I do not like idea to uglify IPv4. 585 586 Actually, all the idea behind IPV6_PKTOPTIONS 587 looks not very well thought. For now we latch 588 options, received in the last packet, enqueued 589 by tcp. Feel free to propose better solution. 590 --ANK (980728) 591 */ 592 if (np->rxopt.all) 593 /* 594 * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below 595 * (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example. 596 */ 597 opt_skb = skb_clone(skb, GFP_ATOMIC); 598 599 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 600 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 601 goto reset; 602 if (opt_skb) { 603 /* XXX This is where we would goto ipv6_pktoptions. */ 604 __kfree_skb(opt_skb); 605 } 606 return 0; 607 } 608 609 /* 610 * Step 3: Process LISTEN state 611 * If S.state == LISTEN, 612 * If P.type == Request or P contains a valid Init Cookie option, 613 * (* Must scan the packet's options to check for Init 614 * Cookies. Only Init Cookies are processed here, 615 * however; other options are processed in Step 8. This 616 * scan need only be performed if the endpoint uses Init 617 * Cookies *) 618 * (* Generate a new socket and switch to that socket *) 619 * Set S := new socket for this port pair 620 * S.state = RESPOND 621 * Choose S.ISS (initial seqno) or set from Init Cookies 622 * Initialize S.GAR := S.ISS 623 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 624 * Continue with S.state == RESPOND 625 * (* A Response packet will be generated in Step 11 *) 626 * Otherwise, 627 * Generate Reset(No Connection) unless P.type == Reset 628 * Drop packet and return 629 * 630 * NOTE: the check for the packet types is done in 631 * dccp_rcv_state_process 632 */ 633 634 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 635 goto reset; 636 if (opt_skb) { 637 /* XXX This is where we would goto ipv6_pktoptions. */ 638 __kfree_skb(opt_skb); 639 } 640 return 0; 641 642 reset: 643 dccp_v6_ctl_send_reset(sk, skb); 644 discard: 645 if (opt_skb != NULL) 646 __kfree_skb(opt_skb); 647 kfree_skb(skb); 648 return 0; 649 } 650 651 static int dccp_v6_rcv(struct sk_buff *skb) 652 { 653 const struct dccp_hdr *dh; 654 bool refcounted; 655 struct sock *sk; 656 int min_cov; 657 658 /* Step 1: Check header basics */ 659 660 if (dccp_invalid_packet(skb)) 661 goto discard_it; 662 663 /* Step 1: If header checksum is incorrect, drop packet and return. */ 664 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, 665 &ipv6_hdr(skb)->daddr)) { 666 DCCP_WARN("dropped packet with invalid checksum\n"); 667 goto discard_it; 668 } 669 670 dh = dccp_hdr(skb); 671 672 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); 673 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; 674 675 if (dccp_packet_without_ack(skb)) 676 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; 677 else 678 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); 679 680 lookup: 681 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), 682 dh->dccph_sport, dh->dccph_dport, 683 inet6_iif(skb), &refcounted); 684 if (!sk) { 685 dccp_pr_debug("failed to look up flow ID in table and " 686 "get corresponding socket\n"); 687 goto no_dccp_socket; 688 } 689 690 /* 691 * Step 2: 692 * ... or S.state == TIMEWAIT, 693 * Generate Reset(No Connection) unless P.type == Reset 694 * Drop packet and return 695 */ 696 if (sk->sk_state == DCCP_TIME_WAIT) { 697 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); 698 inet_twsk_put(inet_twsk(sk)); 699 goto no_dccp_socket; 700 } 701 702 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 703 struct request_sock *req = inet_reqsk(sk); 704 struct sock *nsk; 705 706 sk = req->rsk_listener; 707 if (unlikely(sk->sk_state != DCCP_LISTEN)) { 708 inet_csk_reqsk_queue_drop_and_put(sk, req); 709 goto lookup; 710 } 711 sock_hold(sk); 712 refcounted = true; 713 nsk = dccp_check_req(sk, skb, req); 714 if (!nsk) { 715 reqsk_put(req); 716 goto discard_and_relse; 717 } 718 if (nsk == sk) { 719 reqsk_put(req); 720 } else if (dccp_child_process(sk, nsk, skb)) { 721 dccp_v6_ctl_send_reset(sk, skb); 722 goto discard_and_relse; 723 } else { 724 sock_put(sk); 725 return 0; 726 } 727 } 728 /* 729 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage 730 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted 731 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov 732 */ 733 min_cov = dccp_sk(sk)->dccps_pcrlen; 734 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { 735 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", 736 dh->dccph_cscov, min_cov); 737 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ 738 goto discard_and_relse; 739 } 740 741 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 742 goto discard_and_relse; 743 744 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, 745 refcounted) ? -1 : 0; 746 747 no_dccp_socket: 748 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 749 goto discard_it; 750 /* 751 * Step 2: 752 * If no socket ... 753 * Generate Reset(No Connection) unless P.type == Reset 754 * Drop packet and return 755 */ 756 if (dh->dccph_type != DCCP_PKT_RESET) { 757 DCCP_SKB_CB(skb)->dccpd_reset_code = 758 DCCP_RESET_CODE_NO_CONNECTION; 759 dccp_v6_ctl_send_reset(sk, skb); 760 } 761 762 discard_it: 763 kfree_skb(skb); 764 return 0; 765 766 discard_and_relse: 767 if (refcounted) 768 sock_put(sk); 769 goto discard_it; 770 } 771 772 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 773 int addr_len) 774 { 775 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 776 struct inet_connection_sock *icsk = inet_csk(sk); 777 struct inet_sock *inet = inet_sk(sk); 778 struct ipv6_pinfo *np = inet6_sk(sk); 779 struct dccp_sock *dp = dccp_sk(sk); 780 struct in6_addr *saddr = NULL, *final_p, final; 781 struct ipv6_txoptions *opt; 782 struct flowi6 fl6; 783 struct dst_entry *dst; 784 int addr_type; 785 int err; 786 787 dp->dccps_role = DCCP_ROLE_CLIENT; 788 789 if (addr_len < SIN6_LEN_RFC2133) 790 return -EINVAL; 791 792 if (usin->sin6_family != AF_INET6) 793 return -EAFNOSUPPORT; 794 795 memset(&fl6, 0, sizeof(fl6)); 796 797 if (np->sndflow) { 798 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 799 IP6_ECN_flow_init(fl6.flowlabel); 800 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 801 struct ip6_flowlabel *flowlabel; 802 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 803 if (flowlabel == NULL) 804 return -EINVAL; 805 fl6_sock_release(flowlabel); 806 } 807 } 808 /* 809 * connect() to INADDR_ANY means loopback (BSD'ism). 810 */ 811 if (ipv6_addr_any(&usin->sin6_addr)) 812 usin->sin6_addr.s6_addr[15] = 1; 813 814 addr_type = ipv6_addr_type(&usin->sin6_addr); 815 816 if (addr_type & IPV6_ADDR_MULTICAST) 817 return -ENETUNREACH; 818 819 if (addr_type & IPV6_ADDR_LINKLOCAL) { 820 if (addr_len >= sizeof(struct sockaddr_in6) && 821 usin->sin6_scope_id) { 822 /* If interface is set while binding, indices 823 * must coincide. 824 */ 825 if (sk->sk_bound_dev_if && 826 sk->sk_bound_dev_if != usin->sin6_scope_id) 827 return -EINVAL; 828 829 sk->sk_bound_dev_if = usin->sin6_scope_id; 830 } 831 832 /* Connect to link-local address requires an interface */ 833 if (!sk->sk_bound_dev_if) 834 return -EINVAL; 835 } 836 837 sk->sk_v6_daddr = usin->sin6_addr; 838 np->flow_label = fl6.flowlabel; 839 840 /* 841 * DCCP over IPv4 842 */ 843 if (addr_type == IPV6_ADDR_MAPPED) { 844 u32 exthdrlen = icsk->icsk_ext_hdr_len; 845 struct sockaddr_in sin; 846 847 SOCK_DEBUG(sk, "connect: ipv4 mapped\n"); 848 849 if (__ipv6_only_sock(sk)) 850 return -ENETUNREACH; 851 852 sin.sin_family = AF_INET; 853 sin.sin_port = usin->sin6_port; 854 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 855 856 icsk->icsk_af_ops = &dccp_ipv6_mapped; 857 sk->sk_backlog_rcv = dccp_v4_do_rcv; 858 859 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 860 if (err) { 861 icsk->icsk_ext_hdr_len = exthdrlen; 862 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 863 sk->sk_backlog_rcv = dccp_v6_do_rcv; 864 goto failure; 865 } 866 np->saddr = sk->sk_v6_rcv_saddr; 867 return err; 868 } 869 870 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 871 saddr = &sk->sk_v6_rcv_saddr; 872 873 fl6.flowi6_proto = IPPROTO_DCCP; 874 fl6.daddr = sk->sk_v6_daddr; 875 fl6.saddr = saddr ? *saddr : np->saddr; 876 fl6.flowi6_oif = sk->sk_bound_dev_if; 877 fl6.fl6_dport = usin->sin6_port; 878 fl6.fl6_sport = inet->inet_sport; 879 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); 880 881 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 882 final_p = fl6_update_dst(&fl6, opt, &final); 883 884 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 885 if (IS_ERR(dst)) { 886 err = PTR_ERR(dst); 887 goto failure; 888 } 889 890 if (saddr == NULL) { 891 saddr = &fl6.saddr; 892 sk->sk_v6_rcv_saddr = *saddr; 893 } 894 895 /* set the source address */ 896 np->saddr = *saddr; 897 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 898 899 ip6_dst_store(sk, dst, NULL, NULL); 900 901 icsk->icsk_ext_hdr_len = 0; 902 if (opt) 903 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; 904 905 inet->inet_dport = usin->sin6_port; 906 907 dccp_set_state(sk, DCCP_REQUESTING); 908 err = inet6_hash_connect(&dccp_death_row, sk); 909 if (err) 910 goto late_failure; 911 912 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 913 sk->sk_v6_daddr.s6_addr32, 914 inet->inet_sport, 915 inet->inet_dport); 916 err = dccp_connect(sk); 917 if (err) 918 goto late_failure; 919 920 return 0; 921 922 late_failure: 923 dccp_set_state(sk, DCCP_CLOSED); 924 __sk_dst_reset(sk); 925 failure: 926 inet->inet_dport = 0; 927 sk->sk_route_caps = 0; 928 return err; 929 } 930 931 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 932 .queue_xmit = inet6_csk_xmit, 933 .send_check = dccp_v6_send_check, 934 .rebuild_header = inet6_sk_rebuild_header, 935 .conn_request = dccp_v6_conn_request, 936 .syn_recv_sock = dccp_v6_request_recv_sock, 937 .net_header_len = sizeof(struct ipv6hdr), 938 .setsockopt = ipv6_setsockopt, 939 .getsockopt = ipv6_getsockopt, 940 .addr2sockaddr = inet6_csk_addr2sockaddr, 941 .sockaddr_len = sizeof(struct sockaddr_in6), 942 #ifdef CONFIG_COMPAT 943 .compat_setsockopt = compat_ipv6_setsockopt, 944 .compat_getsockopt = compat_ipv6_getsockopt, 945 #endif 946 }; 947 948 /* 949 * DCCP over IPv4 via INET6 API 950 */ 951 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 952 .queue_xmit = ip_queue_xmit, 953 .send_check = dccp_v4_send_check, 954 .rebuild_header = inet_sk_rebuild_header, 955 .conn_request = dccp_v6_conn_request, 956 .syn_recv_sock = dccp_v6_request_recv_sock, 957 .net_header_len = sizeof(struct iphdr), 958 .setsockopt = ipv6_setsockopt, 959 .getsockopt = ipv6_getsockopt, 960 .addr2sockaddr = inet6_csk_addr2sockaddr, 961 .sockaddr_len = sizeof(struct sockaddr_in6), 962 #ifdef CONFIG_COMPAT 963 .compat_setsockopt = compat_ipv6_setsockopt, 964 .compat_getsockopt = compat_ipv6_getsockopt, 965 #endif 966 }; 967 968 /* NOTE: A lot of things set to zero explicitly by call to 969 * sk_alloc() so need not be done here. 970 */ 971 static int dccp_v6_init_sock(struct sock *sk) 972 { 973 static __u8 dccp_v6_ctl_sock_initialized; 974 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 975 976 if (err == 0) { 977 if (unlikely(!dccp_v6_ctl_sock_initialized)) 978 dccp_v6_ctl_sock_initialized = 1; 979 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 980 } 981 982 return err; 983 } 984 985 static void dccp_v6_destroy_sock(struct sock *sk) 986 { 987 dccp_destroy_sock(sk); 988 inet6_destroy_sock(sk); 989 } 990 991 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 992 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 993 }; 994 995 static struct proto dccp_v6_prot = { 996 .name = "DCCPv6", 997 .owner = THIS_MODULE, 998 .close = dccp_close, 999 .connect = dccp_v6_connect, 1000 .disconnect = dccp_disconnect, 1001 .ioctl = dccp_ioctl, 1002 .init = dccp_v6_init_sock, 1003 .setsockopt = dccp_setsockopt, 1004 .getsockopt = dccp_getsockopt, 1005 .sendmsg = dccp_sendmsg, 1006 .recvmsg = dccp_recvmsg, 1007 .backlog_rcv = dccp_v6_do_rcv, 1008 .hash = inet6_hash, 1009 .unhash = inet_unhash, 1010 .accept = inet_csk_accept, 1011 .get_port = inet_csk_get_port, 1012 .shutdown = dccp_shutdown, 1013 .destroy = dccp_v6_destroy_sock, 1014 .orphan_count = &dccp_orphan_count, 1015 .max_header = MAX_DCCP_HEADER, 1016 .obj_size = sizeof(struct dccp6_sock), 1017 .slab_flags = SLAB_DESTROY_BY_RCU, 1018 .rsk_prot = &dccp6_request_sock_ops, 1019 .twsk_prot = &dccp6_timewait_sock_ops, 1020 .h.hashinfo = &dccp_hashinfo, 1021 #ifdef CONFIG_COMPAT 1022 .compat_setsockopt = compat_dccp_setsockopt, 1023 .compat_getsockopt = compat_dccp_getsockopt, 1024 #endif 1025 }; 1026 1027 static const struct inet6_protocol dccp_v6_protocol = { 1028 .handler = dccp_v6_rcv, 1029 .err_handler = dccp_v6_err, 1030 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1031 }; 1032 1033 static const struct proto_ops inet6_dccp_ops = { 1034 .family = PF_INET6, 1035 .owner = THIS_MODULE, 1036 .release = inet6_release, 1037 .bind = inet6_bind, 1038 .connect = inet_stream_connect, 1039 .socketpair = sock_no_socketpair, 1040 .accept = inet_accept, 1041 .getname = inet6_getname, 1042 .poll = dccp_poll, 1043 .ioctl = inet6_ioctl, 1044 .listen = inet_dccp_listen, 1045 .shutdown = inet_shutdown, 1046 .setsockopt = sock_common_setsockopt, 1047 .getsockopt = sock_common_getsockopt, 1048 .sendmsg = inet_sendmsg, 1049 .recvmsg = sock_common_recvmsg, 1050 .mmap = sock_no_mmap, 1051 .sendpage = sock_no_sendpage, 1052 #ifdef CONFIG_COMPAT 1053 .compat_setsockopt = compat_sock_common_setsockopt, 1054 .compat_getsockopt = compat_sock_common_getsockopt, 1055 #endif 1056 }; 1057 1058 static struct inet_protosw dccp_v6_protosw = { 1059 .type = SOCK_DCCP, 1060 .protocol = IPPROTO_DCCP, 1061 .prot = &dccp_v6_prot, 1062 .ops = &inet6_dccp_ops, 1063 .flags = INET_PROTOSW_ICSK, 1064 }; 1065 1066 static int __net_init dccp_v6_init_net(struct net *net) 1067 { 1068 if (dccp_hashinfo.bhash == NULL) 1069 return -ESOCKTNOSUPPORT; 1070 1071 return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6, 1072 SOCK_DCCP, IPPROTO_DCCP, net); 1073 } 1074 1075 static void __net_exit dccp_v6_exit_net(struct net *net) 1076 { 1077 inet_ctl_sock_destroy(net->dccp.v6_ctl_sk); 1078 } 1079 1080 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list) 1081 { 1082 inet_twsk_purge(&dccp_hashinfo, AF_INET6); 1083 } 1084 1085 static struct pernet_operations dccp_v6_ops = { 1086 .init = dccp_v6_init_net, 1087 .exit = dccp_v6_exit_net, 1088 .exit_batch = dccp_v6_exit_batch, 1089 }; 1090 1091 static int __init dccp_v6_init(void) 1092 { 1093 int err = proto_register(&dccp_v6_prot, 1); 1094 1095 if (err != 0) 1096 goto out; 1097 1098 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1099 if (err != 0) 1100 goto out_unregister_proto; 1101 1102 inet6_register_protosw(&dccp_v6_protosw); 1103 1104 err = register_pernet_subsys(&dccp_v6_ops); 1105 if (err != 0) 1106 goto out_destroy_ctl_sock; 1107 out: 1108 return err; 1109 1110 out_destroy_ctl_sock: 1111 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1112 inet6_unregister_protosw(&dccp_v6_protosw); 1113 out_unregister_proto: 1114 proto_unregister(&dccp_v6_prot); 1115 goto out; 1116 } 1117 1118 static void __exit dccp_v6_exit(void) 1119 { 1120 unregister_pernet_subsys(&dccp_v6_ops); 1121 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1122 inet6_unregister_protosw(&dccp_v6_protosw); 1123 proto_unregister(&dccp_v6_prot); 1124 } 1125 1126 module_init(dccp_v6_init); 1127 module_exit(dccp_v6_exit); 1128 1129 /* 1130 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) 1131 * values directly, Also cover the case where the protocol is not specified, 1132 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP 1133 */ 1134 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6); 1135 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6); 1136 MODULE_LICENSE("GPL"); 1137 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>"); 1138 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol"); 1139