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 = (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(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(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(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(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(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 rcu_read_lock(); 206 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final); 207 rcu_read_unlock(); 208 209 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 210 if (IS_ERR(dst)) { 211 err = PTR_ERR(dst); 212 dst = NULL; 213 goto done; 214 } 215 216 skb = dccp_make_response(sk, dst, req); 217 if (skb != NULL) { 218 struct dccp_hdr *dh = dccp_hdr(skb); 219 220 dh->dccph_checksum = dccp_v6_csum_finish(skb, 221 &ireq->ir_v6_loc_addr, 222 &ireq->ir_v6_rmt_addr); 223 fl6.daddr = ireq->ir_v6_rmt_addr; 224 rcu_read_lock(); 225 err = ip6_xmit(sk, skb, &fl6, rcu_dereference(np->opt), 226 np->tclass); 227 rcu_read_unlock(); 228 err = net_xmit_eval(err); 229 } 230 231 done: 232 dst_release(dst); 233 return err; 234 } 235 236 static void dccp_v6_reqsk_destructor(struct request_sock *req) 237 { 238 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); 239 kfree_skb(inet_rsk(req)->pktopts); 240 } 241 242 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) 243 { 244 const struct ipv6hdr *rxip6h; 245 struct sk_buff *skb; 246 struct flowi6 fl6; 247 struct net *net = dev_net(skb_dst(rxskb)->dev); 248 struct sock *ctl_sk = net->dccp.v6_ctl_sk; 249 struct dst_entry *dst; 250 251 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) 252 return; 253 254 if (!ipv6_unicast_destination(rxskb)) 255 return; 256 257 skb = dccp_ctl_make_reset(ctl_sk, rxskb); 258 if (skb == NULL) 259 return; 260 261 rxip6h = ipv6_hdr(rxskb); 262 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr, 263 &rxip6h->daddr); 264 265 memset(&fl6, 0, sizeof(fl6)); 266 fl6.daddr = rxip6h->saddr; 267 fl6.saddr = rxip6h->daddr; 268 269 fl6.flowi6_proto = IPPROTO_DCCP; 270 fl6.flowi6_oif = inet6_iif(rxskb); 271 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport; 272 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport; 273 security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6)); 274 275 /* sk = NULL, but it is safe for now. RST socket required. */ 276 dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL); 277 if (!IS_ERR(dst)) { 278 skb_dst_set(skb, dst); 279 ip6_xmit(ctl_sk, skb, &fl6, NULL, 0); 280 DCCP_INC_STATS(DCCP_MIB_OUTSEGS); 281 DCCP_INC_STATS(DCCP_MIB_OUTRSTS); 282 return; 283 } 284 285 kfree_skb(skb); 286 } 287 288 static struct request_sock_ops dccp6_request_sock_ops = { 289 .family = AF_INET6, 290 .obj_size = sizeof(struct dccp6_request_sock), 291 .rtx_syn_ack = dccp_v6_send_response, 292 .send_ack = dccp_reqsk_send_ack, 293 .destructor = dccp_v6_reqsk_destructor, 294 .send_reset = dccp_v6_ctl_send_reset, 295 .syn_ack_timeout = dccp_syn_ack_timeout, 296 }; 297 298 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 299 { 300 struct request_sock *req; 301 struct dccp_request_sock *dreq; 302 struct inet_request_sock *ireq; 303 struct ipv6_pinfo *np = inet6_sk(sk); 304 const __be32 service = dccp_hdr_request(skb)->dccph_req_service; 305 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); 306 307 if (skb->protocol == htons(ETH_P_IP)) 308 return dccp_v4_conn_request(sk, skb); 309 310 if (!ipv6_unicast_destination(skb)) 311 return 0; /* discard, don't send a reset here */ 312 313 if (dccp_bad_service_code(sk, service)) { 314 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; 315 goto drop; 316 } 317 /* 318 * There are no SYN attacks on IPv6, yet... 319 */ 320 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 321 if (inet_csk_reqsk_queue_is_full(sk)) 322 goto drop; 323 324 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) 325 goto drop; 326 327 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true); 328 if (req == NULL) 329 goto drop; 330 331 if (dccp_reqsk_init(req, dccp_sk(sk), skb)) 332 goto drop_and_free; 333 334 dreq = dccp_rsk(req); 335 if (dccp_parse_options(sk, dreq, skb)) 336 goto drop_and_free; 337 338 if (security_inet_conn_request(sk, skb, req)) 339 goto drop_and_free; 340 341 ireq = inet_rsk(req); 342 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; 343 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; 344 ireq->ireq_family = AF_INET6; 345 346 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) || 347 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || 348 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { 349 atomic_inc(&skb->users); 350 ireq->pktopts = skb; 351 } 352 ireq->ir_iif = sk->sk_bound_dev_if; 353 354 /* So that link locals have meaning */ 355 if (!sk->sk_bound_dev_if && 356 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 357 ireq->ir_iif = inet6_iif(skb); 358 359 /* 360 * Step 3: Process LISTEN state 361 * 362 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 363 * 364 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 365 */ 366 dreq->dreq_isr = dcb->dccpd_seq; 367 dreq->dreq_gsr = dreq->dreq_isr; 368 dreq->dreq_iss = dccp_v6_init_sequence(skb); 369 dreq->dreq_gss = dreq->dreq_iss; 370 dreq->dreq_service = service; 371 372 if (dccp_v6_send_response(sk, req)) 373 goto drop_and_free; 374 375 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 376 return 0; 377 378 drop_and_free: 379 reqsk_free(req); 380 drop: 381 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 382 return -1; 383 } 384 385 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 386 struct sk_buff *skb, 387 struct request_sock *req, 388 struct dst_entry *dst, 389 struct request_sock *req_unhash, 390 bool *own_req) 391 { 392 struct inet_request_sock *ireq = inet_rsk(req); 393 struct ipv6_pinfo *newnp; 394 const struct ipv6_pinfo *np = inet6_sk(sk); 395 struct ipv6_txoptions *opt; 396 struct inet_sock *newinet; 397 struct dccp6_sock *newdp6; 398 struct sock *newsk; 399 400 if (skb->protocol == htons(ETH_P_IP)) { 401 /* 402 * v6 mapped 403 */ 404 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 405 req_unhash, own_req); 406 if (newsk == NULL) 407 return NULL; 408 409 newdp6 = (struct dccp6_sock *)newsk; 410 newinet = inet_sk(newsk); 411 newinet->pinet6 = &newdp6->inet6; 412 newnp = inet6_sk(newsk); 413 414 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 415 416 newnp->saddr = newsk->sk_v6_rcv_saddr; 417 418 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 419 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 420 newnp->pktoptions = NULL; 421 newnp->opt = NULL; 422 newnp->mcast_oif = inet6_iif(skb); 423 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 424 425 /* 426 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 427 * here, dccp_create_openreq_child now does this for us, see the comment in 428 * that function for the gory details. -acme 429 */ 430 431 /* It is tricky place. Until this moment IPv4 tcp 432 worked with IPv6 icsk.icsk_af_ops. 433 Sync it now. 434 */ 435 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 436 437 return newsk; 438 } 439 440 441 if (sk_acceptq_is_full(sk)) 442 goto out_overflow; 443 444 if (!dst) { 445 struct flowi6 fl6; 446 447 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 448 if (!dst) 449 goto out; 450 } 451 452 newsk = dccp_create_openreq_child(sk, req, skb); 453 if (newsk == NULL) 454 goto out_nonewsk; 455 456 /* 457 * No need to charge this sock to the relevant IPv6 refcnt debug socks 458 * count here, dccp_create_openreq_child now does this for us, see the 459 * comment in that function for the gory details. -acme 460 */ 461 462 ip6_dst_store(newsk, dst, NULL, NULL); 463 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 464 NETIF_F_TSO); 465 newdp6 = (struct dccp6_sock *)newsk; 466 newinet = inet_sk(newsk); 467 newinet->pinet6 = &newdp6->inet6; 468 newnp = inet6_sk(newsk); 469 470 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 471 472 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 473 newnp->saddr = ireq->ir_v6_loc_addr; 474 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 475 newsk->sk_bound_dev_if = ireq->ir_iif; 476 477 /* Now IPv6 options... 478 479 First: no IPv4 options. 480 */ 481 newinet->inet_opt = NULL; 482 483 /* Clone RX bits */ 484 newnp->rxopt.all = np->rxopt.all; 485 486 newnp->pktoptions = NULL; 487 newnp->opt = NULL; 488 newnp->mcast_oif = inet6_iif(skb); 489 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 490 491 /* 492 * Clone native IPv6 options from listening socket (if any) 493 * 494 * Yes, keeping reference count would be much more clever, but we make 495 * one more one thing there: reattach optmem to newsk. 496 */ 497 opt = rcu_dereference(np->opt); 498 if (opt) { 499 opt = ipv6_dup_options(newsk, opt); 500 RCU_INIT_POINTER(newnp->opt, opt); 501 } 502 inet_csk(newsk)->icsk_ext_hdr_len = 0; 503 if (opt) 504 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 505 opt->opt_flen; 506 507 dccp_sync_mss(newsk, dst_mtu(dst)); 508 509 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 510 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 511 512 if (__inet_inherit_port(sk, newsk) < 0) { 513 inet_csk_prepare_forced_close(newsk); 514 dccp_done(newsk); 515 goto out; 516 } 517 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); 518 /* Clone pktoptions received with SYN, if we own the req */ 519 if (*own_req && ireq->pktopts) { 520 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC); 521 consume_skb(ireq->pktopts); 522 ireq->pktopts = NULL; 523 if (newnp->pktoptions) 524 skb_set_owner_r(newnp->pktoptions, newsk); 525 } 526 527 return newsk; 528 529 out_overflow: 530 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 531 out_nonewsk: 532 dst_release(dst); 533 out: 534 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 535 return NULL; 536 } 537 538 /* The socket must have it's spinlock held when we get 539 * here. 540 * 541 * We have a potential double-lock case here, so even when 542 * doing backlog processing we use the BH locking scheme. 543 * This is because we cannot sleep with the original spinlock 544 * held. 545 */ 546 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 547 { 548 struct ipv6_pinfo *np = inet6_sk(sk); 549 struct sk_buff *opt_skb = NULL; 550 551 /* Imagine: socket is IPv6. IPv4 packet arrives, 552 goes to IPv4 receive handler and backlogged. 553 From backlog it always goes here. Kerboom... 554 Fortunately, dccp_rcv_established and rcv_established 555 handle them correctly, but it is not case with 556 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 557 */ 558 559 if (skb->protocol == htons(ETH_P_IP)) 560 return dccp_v4_do_rcv(sk, skb); 561 562 if (sk_filter(sk, skb)) 563 goto discard; 564 565 /* 566 * socket locking is here for SMP purposes as backlog rcv is currently 567 * called with bh processing disabled. 568 */ 569 570 /* Do Stevens' IPV6_PKTOPTIONS. 571 572 Yes, guys, it is the only place in our code, where we 573 may make it not affecting IPv4. 574 The rest of code is protocol independent, 575 and I do not like idea to uglify IPv4. 576 577 Actually, all the idea behind IPV6_PKTOPTIONS 578 looks not very well thought. For now we latch 579 options, received in the last packet, enqueued 580 by tcp. Feel free to propose better solution. 581 --ANK (980728) 582 */ 583 if (np->rxopt.all) 584 /* 585 * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below 586 * (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example. 587 */ 588 opt_skb = skb_clone(skb, GFP_ATOMIC); 589 590 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 591 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 592 goto reset; 593 if (opt_skb) { 594 /* XXX This is where we would goto ipv6_pktoptions. */ 595 __kfree_skb(opt_skb); 596 } 597 return 0; 598 } 599 600 /* 601 * Step 3: Process LISTEN state 602 * If S.state == LISTEN, 603 * If P.type == Request or P contains a valid Init Cookie option, 604 * (* Must scan the packet's options to check for Init 605 * Cookies. Only Init Cookies are processed here, 606 * however; other options are processed in Step 8. This 607 * scan need only be performed if the endpoint uses Init 608 * Cookies *) 609 * (* Generate a new socket and switch to that socket *) 610 * Set S := new socket for this port pair 611 * S.state = RESPOND 612 * Choose S.ISS (initial seqno) or set from Init Cookies 613 * Initialize S.GAR := S.ISS 614 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 615 * Continue with S.state == RESPOND 616 * (* A Response packet will be generated in Step 11 *) 617 * Otherwise, 618 * Generate Reset(No Connection) unless P.type == Reset 619 * Drop packet and return 620 * 621 * NOTE: the check for the packet types is done in 622 * dccp_rcv_state_process 623 */ 624 625 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 626 goto reset; 627 if (opt_skb) { 628 /* XXX This is where we would goto ipv6_pktoptions. */ 629 __kfree_skb(opt_skb); 630 } 631 return 0; 632 633 reset: 634 dccp_v6_ctl_send_reset(sk, skb); 635 discard: 636 if (opt_skb != NULL) 637 __kfree_skb(opt_skb); 638 kfree_skb(skb); 639 return 0; 640 } 641 642 static int dccp_v6_rcv(struct sk_buff *skb) 643 { 644 const struct dccp_hdr *dh; 645 bool refcounted; 646 struct sock *sk; 647 int min_cov; 648 649 /* Step 1: Check header basics */ 650 651 if (dccp_invalid_packet(skb)) 652 goto discard_it; 653 654 /* Step 1: If header checksum is incorrect, drop packet and return. */ 655 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, 656 &ipv6_hdr(skb)->daddr)) { 657 DCCP_WARN("dropped packet with invalid checksum\n"); 658 goto discard_it; 659 } 660 661 dh = dccp_hdr(skb); 662 663 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); 664 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; 665 666 if (dccp_packet_without_ack(skb)) 667 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; 668 else 669 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); 670 671 lookup: 672 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), 673 dh->dccph_sport, dh->dccph_dport, 674 inet6_iif(skb), &refcounted); 675 if (!sk) { 676 dccp_pr_debug("failed to look up flow ID in table and " 677 "get corresponding socket\n"); 678 goto no_dccp_socket; 679 } 680 681 /* 682 * Step 2: 683 * ... or S.state == TIMEWAIT, 684 * Generate Reset(No Connection) unless P.type == Reset 685 * Drop packet and return 686 */ 687 if (sk->sk_state == DCCP_TIME_WAIT) { 688 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); 689 inet_twsk_put(inet_twsk(sk)); 690 goto no_dccp_socket; 691 } 692 693 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 694 struct request_sock *req = inet_reqsk(sk); 695 struct sock *nsk; 696 697 sk = req->rsk_listener; 698 if (unlikely(sk->sk_state != DCCP_LISTEN)) { 699 inet_csk_reqsk_queue_drop_and_put(sk, req); 700 goto lookup; 701 } 702 sock_hold(sk); 703 refcounted = true; 704 nsk = dccp_check_req(sk, skb, req); 705 if (!nsk) { 706 reqsk_put(req); 707 goto discard_and_relse; 708 } 709 if (nsk == sk) { 710 reqsk_put(req); 711 } else if (dccp_child_process(sk, nsk, skb)) { 712 dccp_v6_ctl_send_reset(sk, skb); 713 goto discard_and_relse; 714 } else { 715 sock_put(sk); 716 return 0; 717 } 718 } 719 /* 720 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage 721 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted 722 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov 723 */ 724 min_cov = dccp_sk(sk)->dccps_pcrlen; 725 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { 726 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", 727 dh->dccph_cscov, min_cov); 728 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ 729 goto discard_and_relse; 730 } 731 732 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 733 goto discard_and_relse; 734 735 return sk_receive_skb(sk, skb, 1) ? -1 : 0; 736 737 no_dccp_socket: 738 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 739 goto discard_it; 740 /* 741 * Step 2: 742 * If no socket ... 743 * Generate Reset(No Connection) unless P.type == Reset 744 * Drop packet and return 745 */ 746 if (dh->dccph_type != DCCP_PKT_RESET) { 747 DCCP_SKB_CB(skb)->dccpd_reset_code = 748 DCCP_RESET_CODE_NO_CONNECTION; 749 dccp_v6_ctl_send_reset(sk, skb); 750 } 751 752 discard_it: 753 kfree_skb(skb); 754 return 0; 755 756 discard_and_relse: 757 if (refcounted) 758 sock_put(sk); 759 goto discard_it; 760 } 761 762 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 763 int addr_len) 764 { 765 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 766 struct inet_connection_sock *icsk = inet_csk(sk); 767 struct inet_sock *inet = inet_sk(sk); 768 struct ipv6_pinfo *np = inet6_sk(sk); 769 struct dccp_sock *dp = dccp_sk(sk); 770 struct in6_addr *saddr = NULL, *final_p, final; 771 struct ipv6_txoptions *opt; 772 struct flowi6 fl6; 773 struct dst_entry *dst; 774 int addr_type; 775 int err; 776 777 dp->dccps_role = DCCP_ROLE_CLIENT; 778 779 if (addr_len < SIN6_LEN_RFC2133) 780 return -EINVAL; 781 782 if (usin->sin6_family != AF_INET6) 783 return -EAFNOSUPPORT; 784 785 memset(&fl6, 0, sizeof(fl6)); 786 787 if (np->sndflow) { 788 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 789 IP6_ECN_flow_init(fl6.flowlabel); 790 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 791 struct ip6_flowlabel *flowlabel; 792 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 793 if (flowlabel == NULL) 794 return -EINVAL; 795 fl6_sock_release(flowlabel); 796 } 797 } 798 /* 799 * connect() to INADDR_ANY means loopback (BSD'ism). 800 */ 801 if (ipv6_addr_any(&usin->sin6_addr)) 802 usin->sin6_addr.s6_addr[15] = 1; 803 804 addr_type = ipv6_addr_type(&usin->sin6_addr); 805 806 if (addr_type & IPV6_ADDR_MULTICAST) 807 return -ENETUNREACH; 808 809 if (addr_type & IPV6_ADDR_LINKLOCAL) { 810 if (addr_len >= sizeof(struct sockaddr_in6) && 811 usin->sin6_scope_id) { 812 /* If interface is set while binding, indices 813 * must coincide. 814 */ 815 if (sk->sk_bound_dev_if && 816 sk->sk_bound_dev_if != usin->sin6_scope_id) 817 return -EINVAL; 818 819 sk->sk_bound_dev_if = usin->sin6_scope_id; 820 } 821 822 /* Connect to link-local address requires an interface */ 823 if (!sk->sk_bound_dev_if) 824 return -EINVAL; 825 } 826 827 sk->sk_v6_daddr = usin->sin6_addr; 828 np->flow_label = fl6.flowlabel; 829 830 /* 831 * DCCP over IPv4 832 */ 833 if (addr_type == IPV6_ADDR_MAPPED) { 834 u32 exthdrlen = icsk->icsk_ext_hdr_len; 835 struct sockaddr_in sin; 836 837 SOCK_DEBUG(sk, "connect: ipv4 mapped\n"); 838 839 if (__ipv6_only_sock(sk)) 840 return -ENETUNREACH; 841 842 sin.sin_family = AF_INET; 843 sin.sin_port = usin->sin6_port; 844 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 845 846 icsk->icsk_af_ops = &dccp_ipv6_mapped; 847 sk->sk_backlog_rcv = dccp_v4_do_rcv; 848 849 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 850 if (err) { 851 icsk->icsk_ext_hdr_len = exthdrlen; 852 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 853 sk->sk_backlog_rcv = dccp_v6_do_rcv; 854 goto failure; 855 } 856 np->saddr = sk->sk_v6_rcv_saddr; 857 return err; 858 } 859 860 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 861 saddr = &sk->sk_v6_rcv_saddr; 862 863 fl6.flowi6_proto = IPPROTO_DCCP; 864 fl6.daddr = sk->sk_v6_daddr; 865 fl6.saddr = saddr ? *saddr : np->saddr; 866 fl6.flowi6_oif = sk->sk_bound_dev_if; 867 fl6.fl6_dport = usin->sin6_port; 868 fl6.fl6_sport = inet->inet_sport; 869 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); 870 871 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 872 final_p = fl6_update_dst(&fl6, opt, &final); 873 874 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 875 if (IS_ERR(dst)) { 876 err = PTR_ERR(dst); 877 goto failure; 878 } 879 880 if (saddr == NULL) { 881 saddr = &fl6.saddr; 882 sk->sk_v6_rcv_saddr = *saddr; 883 } 884 885 /* set the source address */ 886 np->saddr = *saddr; 887 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 888 889 ip6_dst_store(sk, dst, NULL, NULL); 890 891 icsk->icsk_ext_hdr_len = 0; 892 if (opt) 893 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; 894 895 inet->inet_dport = usin->sin6_port; 896 897 dccp_set_state(sk, DCCP_REQUESTING); 898 err = inet6_hash_connect(&dccp_death_row, sk); 899 if (err) 900 goto late_failure; 901 902 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 903 sk->sk_v6_daddr.s6_addr32, 904 inet->inet_sport, 905 inet->inet_dport); 906 err = dccp_connect(sk); 907 if (err) 908 goto late_failure; 909 910 return 0; 911 912 late_failure: 913 dccp_set_state(sk, DCCP_CLOSED); 914 __sk_dst_reset(sk); 915 failure: 916 inet->inet_dport = 0; 917 sk->sk_route_caps = 0; 918 return err; 919 } 920 921 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 922 .queue_xmit = inet6_csk_xmit, 923 .send_check = dccp_v6_send_check, 924 .rebuild_header = inet6_sk_rebuild_header, 925 .conn_request = dccp_v6_conn_request, 926 .syn_recv_sock = dccp_v6_request_recv_sock, 927 .net_header_len = sizeof(struct ipv6hdr), 928 .setsockopt = ipv6_setsockopt, 929 .getsockopt = ipv6_getsockopt, 930 .addr2sockaddr = inet6_csk_addr2sockaddr, 931 .sockaddr_len = sizeof(struct sockaddr_in6), 932 .bind_conflict = inet6_csk_bind_conflict, 933 #ifdef CONFIG_COMPAT 934 .compat_setsockopt = compat_ipv6_setsockopt, 935 .compat_getsockopt = compat_ipv6_getsockopt, 936 #endif 937 }; 938 939 /* 940 * DCCP over IPv4 via INET6 API 941 */ 942 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 943 .queue_xmit = ip_queue_xmit, 944 .send_check = dccp_v4_send_check, 945 .rebuild_header = inet_sk_rebuild_header, 946 .conn_request = dccp_v6_conn_request, 947 .syn_recv_sock = dccp_v6_request_recv_sock, 948 .net_header_len = sizeof(struct iphdr), 949 .setsockopt = ipv6_setsockopt, 950 .getsockopt = ipv6_getsockopt, 951 .addr2sockaddr = inet6_csk_addr2sockaddr, 952 .sockaddr_len = sizeof(struct sockaddr_in6), 953 #ifdef CONFIG_COMPAT 954 .compat_setsockopt = compat_ipv6_setsockopt, 955 .compat_getsockopt = compat_ipv6_getsockopt, 956 #endif 957 }; 958 959 /* NOTE: A lot of things set to zero explicitly by call to 960 * sk_alloc() so need not be done here. 961 */ 962 static int dccp_v6_init_sock(struct sock *sk) 963 { 964 static __u8 dccp_v6_ctl_sock_initialized; 965 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 966 967 if (err == 0) { 968 if (unlikely(!dccp_v6_ctl_sock_initialized)) 969 dccp_v6_ctl_sock_initialized = 1; 970 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 971 } 972 973 return err; 974 } 975 976 static void dccp_v6_destroy_sock(struct sock *sk) 977 { 978 dccp_destroy_sock(sk); 979 inet6_destroy_sock(sk); 980 } 981 982 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 983 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 984 }; 985 986 static struct proto dccp_v6_prot = { 987 .name = "DCCPv6", 988 .owner = THIS_MODULE, 989 .close = dccp_close, 990 .connect = dccp_v6_connect, 991 .disconnect = dccp_disconnect, 992 .ioctl = dccp_ioctl, 993 .init = dccp_v6_init_sock, 994 .setsockopt = dccp_setsockopt, 995 .getsockopt = dccp_getsockopt, 996 .sendmsg = dccp_sendmsg, 997 .recvmsg = dccp_recvmsg, 998 .backlog_rcv = dccp_v6_do_rcv, 999 .hash = inet6_hash, 1000 .unhash = inet_unhash, 1001 .accept = inet_csk_accept, 1002 .get_port = inet_csk_get_port, 1003 .shutdown = dccp_shutdown, 1004 .destroy = dccp_v6_destroy_sock, 1005 .orphan_count = &dccp_orphan_count, 1006 .max_header = MAX_DCCP_HEADER, 1007 .obj_size = sizeof(struct dccp6_sock), 1008 .slab_flags = SLAB_DESTROY_BY_RCU, 1009 .rsk_prot = &dccp6_request_sock_ops, 1010 .twsk_prot = &dccp6_timewait_sock_ops, 1011 .h.hashinfo = &dccp_hashinfo, 1012 #ifdef CONFIG_COMPAT 1013 .compat_setsockopt = compat_dccp_setsockopt, 1014 .compat_getsockopt = compat_dccp_getsockopt, 1015 #endif 1016 }; 1017 1018 static const struct inet6_protocol dccp_v6_protocol = { 1019 .handler = dccp_v6_rcv, 1020 .err_handler = dccp_v6_err, 1021 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1022 }; 1023 1024 static const struct proto_ops inet6_dccp_ops = { 1025 .family = PF_INET6, 1026 .owner = THIS_MODULE, 1027 .release = inet6_release, 1028 .bind = inet6_bind, 1029 .connect = inet_stream_connect, 1030 .socketpair = sock_no_socketpair, 1031 .accept = inet_accept, 1032 .getname = inet6_getname, 1033 .poll = dccp_poll, 1034 .ioctl = inet6_ioctl, 1035 .listen = inet_dccp_listen, 1036 .shutdown = inet_shutdown, 1037 .setsockopt = sock_common_setsockopt, 1038 .getsockopt = sock_common_getsockopt, 1039 .sendmsg = inet_sendmsg, 1040 .recvmsg = sock_common_recvmsg, 1041 .mmap = sock_no_mmap, 1042 .sendpage = sock_no_sendpage, 1043 #ifdef CONFIG_COMPAT 1044 .compat_setsockopt = compat_sock_common_setsockopt, 1045 .compat_getsockopt = compat_sock_common_getsockopt, 1046 #endif 1047 }; 1048 1049 static struct inet_protosw dccp_v6_protosw = { 1050 .type = SOCK_DCCP, 1051 .protocol = IPPROTO_DCCP, 1052 .prot = &dccp_v6_prot, 1053 .ops = &inet6_dccp_ops, 1054 .flags = INET_PROTOSW_ICSK, 1055 }; 1056 1057 static int __net_init dccp_v6_init_net(struct net *net) 1058 { 1059 if (dccp_hashinfo.bhash == NULL) 1060 return -ESOCKTNOSUPPORT; 1061 1062 return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6, 1063 SOCK_DCCP, IPPROTO_DCCP, net); 1064 } 1065 1066 static void __net_exit dccp_v6_exit_net(struct net *net) 1067 { 1068 inet_ctl_sock_destroy(net->dccp.v6_ctl_sk); 1069 } 1070 1071 static struct pernet_operations dccp_v6_ops = { 1072 .init = dccp_v6_init_net, 1073 .exit = dccp_v6_exit_net, 1074 }; 1075 1076 static int __init dccp_v6_init(void) 1077 { 1078 int err = proto_register(&dccp_v6_prot, 1); 1079 1080 if (err != 0) 1081 goto out; 1082 1083 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1084 if (err != 0) 1085 goto out_unregister_proto; 1086 1087 inet6_register_protosw(&dccp_v6_protosw); 1088 1089 err = register_pernet_subsys(&dccp_v6_ops); 1090 if (err != 0) 1091 goto out_destroy_ctl_sock; 1092 out: 1093 return err; 1094 1095 out_destroy_ctl_sock: 1096 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1097 inet6_unregister_protosw(&dccp_v6_protosw); 1098 out_unregister_proto: 1099 proto_unregister(&dccp_v6_prot); 1100 goto out; 1101 } 1102 1103 static void __exit dccp_v6_exit(void) 1104 { 1105 unregister_pernet_subsys(&dccp_v6_ops); 1106 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1107 inet6_unregister_protosw(&dccp_v6_protosw); 1108 proto_unregister(&dccp_v6_prot); 1109 } 1110 1111 module_init(dccp_v6_init); 1112 module_exit(dccp_v6_exit); 1113 1114 /* 1115 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) 1116 * values directly, Also cover the case where the protocol is not specified, 1117 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP 1118 */ 1119 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6); 1120 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6); 1121 MODULE_LICENSE("GPL"); 1122 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>"); 1123 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol"); 1124