1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * DCCP over IPv6 4 * Linux INET6 implementation 5 * 6 * Based on net/dccp6/ipv6.c 7 * 8 * Arnaldo Carvalho de Melo <acme@ghostprotocols.net> 9 */ 10 11 #include <linux/module.h> 12 #include <linux/random.h> 13 #include <linux/slab.h> 14 #include <linux/xfrm.h> 15 #include <linux/string.h> 16 17 #include <net/addrconf.h> 18 #include <net/inet_common.h> 19 #include <net/inet_hashtables.h> 20 #include <net/inet_sock.h> 21 #include <net/inet6_connection_sock.h> 22 #include <net/inet6_hashtables.h> 23 #include <net/ip6_route.h> 24 #include <net/ipv6.h> 25 #include <net/protocol.h> 26 #include <net/transp_v6.h> 27 #include <net/ip6_checksum.h> 28 #include <net/xfrm.h> 29 #include <net/secure_seq.h> 30 #include <net/netns/generic.h> 31 #include <net/sock.h> 32 33 #include "dccp.h" 34 #include "ipv6.h" 35 #include "feat.h" 36 37 struct dccp_v6_pernet { 38 struct sock *v6_ctl_sk; 39 }; 40 41 static unsigned int dccp_v6_pernet_id __read_mostly; 42 43 /* The per-net v6_ctl_sk is used for sending RSTs and ACKs */ 44 45 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped; 46 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops; 47 48 /* add pseudo-header to DCCP checksum stored in skb->csum */ 49 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb, 50 const struct in6_addr *saddr, 51 const struct in6_addr *daddr) 52 { 53 return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum); 54 } 55 56 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb) 57 { 58 struct ipv6_pinfo *np = inet6_sk(sk); 59 struct dccp_hdr *dh = dccp_hdr(skb); 60 61 dccp_csum_outgoing(skb); 62 dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr); 63 } 64 65 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb) 66 { 67 return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32, 68 ipv6_hdr(skb)->saddr.s6_addr32, 69 dccp_hdr(skb)->dccph_dport, 70 dccp_hdr(skb)->dccph_sport ); 71 72 } 73 74 static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 75 u8 type, u8 code, int offset, __be32 info) 76 { 77 const struct ipv6hdr *hdr; 78 const struct dccp_hdr *dh; 79 struct dccp_sock *dp; 80 struct ipv6_pinfo *np; 81 struct sock *sk; 82 int err; 83 __u64 seq; 84 struct net *net = dev_net(skb->dev); 85 86 /* For the first __dccp_basic_hdr_len() check, we only need dh->dccph_x, 87 * which is in byte 7 of the dccp header. 88 * Our caller (icmpv6_notify()) already pulled 8 bytes for us. 89 * 90 * Later on, we want to access the sequence number fields, which are 91 * beyond 8 bytes, so we have to pskb_may_pull() ourselves. 92 */ 93 dh = (struct dccp_hdr *)(skb->data + offset); 94 if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh))) 95 return -EINVAL; 96 hdr = (const struct ipv6hdr *)skb->data; 97 dh = (struct dccp_hdr *)(skb->data + offset); 98 99 sk = __inet6_lookup_established(net, &dccp_hashinfo, 100 &hdr->daddr, dh->dccph_dport, 101 &hdr->saddr, ntohs(dh->dccph_sport), 102 inet6_iif(skb), 0); 103 104 if (!sk) { 105 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), 106 ICMP6_MIB_INERRORS); 107 return -ENOENT; 108 } 109 110 if (sk->sk_state == DCCP_TIME_WAIT) { 111 inet_twsk_put(inet_twsk(sk)); 112 return 0; 113 } 114 seq = dccp_hdr_seq(dh); 115 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 116 dccp_req_err(sk, seq); 117 return 0; 118 } 119 120 bh_lock_sock(sk); 121 if (sock_owned_by_user(sk)) 122 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 123 124 if (sk->sk_state == DCCP_CLOSED) 125 goto out; 126 127 dp = dccp_sk(sk); 128 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) && 129 !between48(seq, dp->dccps_awl, dp->dccps_awh)) { 130 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 131 goto out; 132 } 133 134 np = inet6_sk(sk); 135 136 if (type == NDISC_REDIRECT) { 137 if (!sock_owned_by_user(sk)) { 138 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie); 139 140 if (dst) 141 dst->ops->redirect(dst, sk, skb); 142 } 143 goto out; 144 } 145 146 if (type == ICMPV6_PKT_TOOBIG) { 147 struct dst_entry *dst = NULL; 148 149 if (!ip6_sk_accept_pmtu(sk)) 150 goto out; 151 152 if (sock_owned_by_user(sk)) 153 goto out; 154 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED)) 155 goto out; 156 157 dst = inet6_csk_update_pmtu(sk, ntohl(info)); 158 if (!dst) 159 goto out; 160 161 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) 162 dccp_sync_mss(sk, dst_mtu(dst)); 163 goto out; 164 } 165 166 icmpv6_err_convert(type, code, &err); 167 168 /* Might be for an request_sock */ 169 switch (sk->sk_state) { 170 case DCCP_REQUESTING: 171 case DCCP_RESPOND: /* Cannot happen. 172 It can, it SYNs are crossed. --ANK */ 173 if (!sock_owned_by_user(sk)) { 174 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 175 sk->sk_err = err; 176 /* 177 * Wake people up to see the error 178 * (see connect in sock.c) 179 */ 180 sk_error_report(sk); 181 dccp_done(sk); 182 } else { 183 WRITE_ONCE(sk->sk_err_soft, err); 184 } 185 goto out; 186 } 187 188 if (!sock_owned_by_user(sk) && np->recverr) { 189 sk->sk_err = err; 190 sk_error_report(sk); 191 } else { 192 WRITE_ONCE(sk->sk_err_soft, err); 193 } 194 out: 195 bh_unlock_sock(sk); 196 sock_put(sk); 197 return 0; 198 } 199 200 201 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req) 202 { 203 struct inet_request_sock *ireq = inet_rsk(req); 204 struct ipv6_pinfo *np = inet6_sk(sk); 205 struct sk_buff *skb; 206 struct in6_addr *final_p, final; 207 struct flowi6 fl6; 208 int err = -1; 209 struct dst_entry *dst; 210 211 memset(&fl6, 0, sizeof(fl6)); 212 fl6.flowi6_proto = IPPROTO_DCCP; 213 fl6.daddr = ireq->ir_v6_rmt_addr; 214 fl6.saddr = ireq->ir_v6_loc_addr; 215 fl6.flowlabel = 0; 216 fl6.flowi6_oif = ireq->ir_iif; 217 fl6.fl6_dport = ireq->ir_rmt_port; 218 fl6.fl6_sport = htons(ireq->ir_num); 219 security_req_classify_flow(req, flowi6_to_flowi_common(&fl6)); 220 221 222 rcu_read_lock(); 223 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final); 224 rcu_read_unlock(); 225 226 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 227 if (IS_ERR(dst)) { 228 err = PTR_ERR(dst); 229 dst = NULL; 230 goto done; 231 } 232 233 skb = dccp_make_response(sk, dst, req); 234 if (skb != NULL) { 235 struct dccp_hdr *dh = dccp_hdr(skb); 236 struct ipv6_txoptions *opt; 237 238 dh->dccph_checksum = dccp_v6_csum_finish(skb, 239 &ireq->ir_v6_loc_addr, 240 &ireq->ir_v6_rmt_addr); 241 fl6.daddr = ireq->ir_v6_rmt_addr; 242 rcu_read_lock(); 243 opt = ireq->ipv6_opt; 244 if (!opt) 245 opt = rcu_dereference(np->opt); 246 err = ip6_xmit(sk, skb, &fl6, READ_ONCE(sk->sk_mark), opt, 247 np->tclass, sk->sk_priority); 248 rcu_read_unlock(); 249 err = net_xmit_eval(err); 250 } 251 252 done: 253 dst_release(dst); 254 return err; 255 } 256 257 static void dccp_v6_reqsk_destructor(struct request_sock *req) 258 { 259 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); 260 kfree(inet_rsk(req)->ipv6_opt); 261 kfree_skb(inet_rsk(req)->pktopts); 262 } 263 264 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) 265 { 266 const struct ipv6hdr *rxip6h; 267 struct sk_buff *skb; 268 struct flowi6 fl6; 269 struct net *net = dev_net(skb_dst(rxskb)->dev); 270 struct dccp_v6_pernet *pn; 271 struct sock *ctl_sk; 272 struct dst_entry *dst; 273 274 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) 275 return; 276 277 if (!ipv6_unicast_destination(rxskb)) 278 return; 279 280 pn = net_generic(net, dccp_v6_pernet_id); 281 ctl_sk = pn->v6_ctl_sk; 282 skb = dccp_ctl_make_reset(ctl_sk, rxskb); 283 if (skb == NULL) 284 return; 285 286 rxip6h = ipv6_hdr(rxskb); 287 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr, 288 &rxip6h->daddr); 289 290 memset(&fl6, 0, sizeof(fl6)); 291 fl6.daddr = rxip6h->saddr; 292 fl6.saddr = rxip6h->daddr; 293 294 fl6.flowi6_proto = IPPROTO_DCCP; 295 fl6.flowi6_oif = inet6_iif(rxskb); 296 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport; 297 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport; 298 security_skb_classify_flow(rxskb, flowi6_to_flowi_common(&fl6)); 299 300 /* sk = NULL, but it is safe for now. RST socket required. */ 301 dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL); 302 if (!IS_ERR(dst)) { 303 skb_dst_set(skb, dst); 304 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0, 0); 305 DCCP_INC_STATS(DCCP_MIB_OUTSEGS); 306 DCCP_INC_STATS(DCCP_MIB_OUTRSTS); 307 return; 308 } 309 310 kfree_skb(skb); 311 } 312 313 static struct request_sock_ops dccp6_request_sock_ops = { 314 .family = AF_INET6, 315 .obj_size = sizeof(struct dccp6_request_sock), 316 .rtx_syn_ack = dccp_v6_send_response, 317 .send_ack = dccp_reqsk_send_ack, 318 .destructor = dccp_v6_reqsk_destructor, 319 .send_reset = dccp_v6_ctl_send_reset, 320 .syn_ack_timeout = dccp_syn_ack_timeout, 321 }; 322 323 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 324 { 325 struct request_sock *req; 326 struct dccp_request_sock *dreq; 327 struct inet_request_sock *ireq; 328 struct ipv6_pinfo *np = inet6_sk(sk); 329 const __be32 service = dccp_hdr_request(skb)->dccph_req_service; 330 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); 331 332 if (skb->protocol == htons(ETH_P_IP)) 333 return dccp_v4_conn_request(sk, skb); 334 335 if (!ipv6_unicast_destination(skb)) 336 return 0; /* discard, don't send a reset here */ 337 338 if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { 339 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); 340 return 0; 341 } 342 343 if (dccp_bad_service_code(sk, service)) { 344 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; 345 goto drop; 346 } 347 /* 348 * There are no SYN attacks on IPv6, yet... 349 */ 350 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 351 if (inet_csk_reqsk_queue_is_full(sk)) 352 goto drop; 353 354 if (sk_acceptq_is_full(sk)) 355 goto drop; 356 357 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true); 358 if (req == NULL) 359 goto drop; 360 361 if (dccp_reqsk_init(req, dccp_sk(sk), skb)) 362 goto drop_and_free; 363 364 dreq = dccp_rsk(req); 365 if (dccp_parse_options(sk, dreq, skb)) 366 goto drop_and_free; 367 368 if (security_inet_conn_request(sk, skb, req)) 369 goto drop_and_free; 370 371 ireq = inet_rsk(req); 372 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; 373 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; 374 ireq->ireq_family = AF_INET6; 375 ireq->ir_mark = inet_request_mark(sk, skb); 376 377 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) || 378 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || 379 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { 380 refcount_inc(&skb->users); 381 ireq->pktopts = skb; 382 } 383 ireq->ir_iif = READ_ONCE(sk->sk_bound_dev_if); 384 385 /* So that link locals have meaning */ 386 if (!ireq->ir_iif && 387 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 388 ireq->ir_iif = inet6_iif(skb); 389 390 /* 391 * Step 3: Process LISTEN state 392 * 393 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 394 * 395 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 396 */ 397 dreq->dreq_isr = dcb->dccpd_seq; 398 dreq->dreq_gsr = dreq->dreq_isr; 399 dreq->dreq_iss = dccp_v6_init_sequence(skb); 400 dreq->dreq_gss = dreq->dreq_iss; 401 dreq->dreq_service = service; 402 403 if (dccp_v6_send_response(sk, req)) 404 goto drop_and_free; 405 406 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 407 reqsk_put(req); 408 return 0; 409 410 drop_and_free: 411 reqsk_free(req); 412 drop: 413 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 414 return -1; 415 } 416 417 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 418 struct sk_buff *skb, 419 struct request_sock *req, 420 struct dst_entry *dst, 421 struct request_sock *req_unhash, 422 bool *own_req) 423 { 424 struct inet_request_sock *ireq = inet_rsk(req); 425 struct ipv6_pinfo *newnp; 426 const struct ipv6_pinfo *np = inet6_sk(sk); 427 struct ipv6_txoptions *opt; 428 struct inet_sock *newinet; 429 struct dccp6_sock *newdp6; 430 struct sock *newsk; 431 432 if (skb->protocol == htons(ETH_P_IP)) { 433 /* 434 * v6 mapped 435 */ 436 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 437 req_unhash, own_req); 438 if (newsk == NULL) 439 return NULL; 440 441 newdp6 = (struct dccp6_sock *)newsk; 442 newinet = inet_sk(newsk); 443 newinet->pinet6 = &newdp6->inet6; 444 newnp = inet6_sk(newsk); 445 446 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 447 448 newnp->saddr = newsk->sk_v6_rcv_saddr; 449 450 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 451 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 452 newnp->pktoptions = NULL; 453 newnp->opt = NULL; 454 newnp->ipv6_mc_list = NULL; 455 newnp->ipv6_ac_list = NULL; 456 newnp->ipv6_fl_list = NULL; 457 newnp->mcast_oif = inet_iif(skb); 458 newnp->mcast_hops = ip_hdr(skb)->ttl; 459 460 /* 461 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 462 * here, dccp_create_openreq_child now does this for us, see the comment in 463 * that function for the gory details. -acme 464 */ 465 466 /* It is tricky place. Until this moment IPv4 tcp 467 worked with IPv6 icsk.icsk_af_ops. 468 Sync it now. 469 */ 470 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 471 472 return newsk; 473 } 474 475 476 if (sk_acceptq_is_full(sk)) 477 goto out_overflow; 478 479 if (!dst) { 480 struct flowi6 fl6; 481 482 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 483 if (!dst) 484 goto out; 485 } 486 487 newsk = dccp_create_openreq_child(sk, req, skb); 488 if (newsk == NULL) 489 goto out_nonewsk; 490 491 /* 492 * No need to charge this sock to the relevant IPv6 refcnt debug socks 493 * count here, dccp_create_openreq_child now does this for us, see the 494 * comment in that function for the gory details. -acme 495 */ 496 497 ip6_dst_store(newsk, dst, NULL, NULL); 498 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 499 NETIF_F_TSO); 500 newdp6 = (struct dccp6_sock *)newsk; 501 newinet = inet_sk(newsk); 502 newinet->pinet6 = &newdp6->inet6; 503 newnp = inet6_sk(newsk); 504 505 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 506 507 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 508 newnp->saddr = ireq->ir_v6_loc_addr; 509 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 510 newsk->sk_bound_dev_if = ireq->ir_iif; 511 512 /* Now IPv6 options... 513 514 First: no IPv4 options. 515 */ 516 newinet->inet_opt = NULL; 517 518 /* Clone RX bits */ 519 newnp->rxopt.all = np->rxopt.all; 520 521 newnp->ipv6_mc_list = NULL; 522 newnp->ipv6_ac_list = NULL; 523 newnp->ipv6_fl_list = NULL; 524 newnp->pktoptions = NULL; 525 newnp->opt = NULL; 526 newnp->mcast_oif = inet6_iif(skb); 527 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 528 529 /* 530 * Clone native IPv6 options from listening socket (if any) 531 * 532 * Yes, keeping reference count would be much more clever, but we make 533 * one more one thing there: reattach optmem to newsk. 534 */ 535 opt = ireq->ipv6_opt; 536 if (!opt) 537 opt = rcu_dereference(np->opt); 538 if (opt) { 539 opt = ipv6_dup_options(newsk, opt); 540 RCU_INIT_POINTER(newnp->opt, opt); 541 } 542 inet_csk(newsk)->icsk_ext_hdr_len = 0; 543 if (opt) 544 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 545 opt->opt_flen; 546 547 dccp_sync_mss(newsk, dst_mtu(dst)); 548 549 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 550 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 551 552 if (__inet_inherit_port(sk, newsk) < 0) { 553 inet_csk_prepare_forced_close(newsk); 554 dccp_done(newsk); 555 goto out; 556 } 557 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL); 558 /* Clone pktoptions received with SYN, if we own the req */ 559 if (*own_req && ireq->pktopts) { 560 newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk); 561 consume_skb(ireq->pktopts); 562 ireq->pktopts = NULL; 563 } 564 565 return newsk; 566 567 out_overflow: 568 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 569 out_nonewsk: 570 dst_release(dst); 571 out: 572 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 573 return NULL; 574 } 575 576 /* The socket must have it's spinlock held when we get 577 * here. 578 * 579 * We have a potential double-lock case here, so even when 580 * doing backlog processing we use the BH locking scheme. 581 * This is because we cannot sleep with the original spinlock 582 * held. 583 */ 584 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 585 { 586 struct ipv6_pinfo *np = inet6_sk(sk); 587 struct sk_buff *opt_skb = NULL; 588 589 /* Imagine: socket is IPv6. IPv4 packet arrives, 590 goes to IPv4 receive handler and backlogged. 591 From backlog it always goes here. Kerboom... 592 Fortunately, dccp_rcv_established and rcv_established 593 handle them correctly, but it is not case with 594 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 595 */ 596 597 if (skb->protocol == htons(ETH_P_IP)) 598 return dccp_v4_do_rcv(sk, skb); 599 600 if (sk_filter(sk, skb)) 601 goto discard; 602 603 /* 604 * socket locking is here for SMP purposes as backlog rcv is currently 605 * called with bh processing disabled. 606 */ 607 608 /* Do Stevens' IPV6_PKTOPTIONS. 609 610 Yes, guys, it is the only place in our code, where we 611 may make it not affecting IPv4. 612 The rest of code is protocol independent, 613 and I do not like idea to uglify IPv4. 614 615 Actually, all the idea behind IPV6_PKTOPTIONS 616 looks not very well thought. For now we latch 617 options, received in the last packet, enqueued 618 by tcp. Feel free to propose better solution. 619 --ANK (980728) 620 */ 621 if (np->rxopt.all) 622 opt_skb = skb_clone_and_charge_r(skb, sk); 623 624 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 625 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 626 goto reset; 627 if (opt_skb) 628 goto ipv6_pktoptions; 629 return 0; 630 } 631 632 /* 633 * Step 3: Process LISTEN state 634 * If S.state == LISTEN, 635 * If P.type == Request or P contains a valid Init Cookie option, 636 * (* Must scan the packet's options to check for Init 637 * Cookies. Only Init Cookies are processed here, 638 * however; other options are processed in Step 8. This 639 * scan need only be performed if the endpoint uses Init 640 * Cookies *) 641 * (* Generate a new socket and switch to that socket *) 642 * Set S := new socket for this port pair 643 * S.state = RESPOND 644 * Choose S.ISS (initial seqno) or set from Init Cookies 645 * Initialize S.GAR := S.ISS 646 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 647 * Continue with S.state == RESPOND 648 * (* A Response packet will be generated in Step 11 *) 649 * Otherwise, 650 * Generate Reset(No Connection) unless P.type == Reset 651 * Drop packet and return 652 * 653 * NOTE: the check for the packet types is done in 654 * dccp_rcv_state_process 655 */ 656 657 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 658 goto reset; 659 if (opt_skb) 660 goto ipv6_pktoptions; 661 return 0; 662 663 reset: 664 dccp_v6_ctl_send_reset(sk, skb); 665 discard: 666 if (opt_skb != NULL) 667 __kfree_skb(opt_skb); 668 kfree_skb(skb); 669 return 0; 670 671 /* Handling IPV6_PKTOPTIONS skb the similar 672 * way it's done for net/ipv6/tcp_ipv6.c 673 */ 674 ipv6_pktoptions: 675 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) { 676 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) 677 np->mcast_oif = inet6_iif(opt_skb); 678 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) 679 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit; 680 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) 681 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); 682 if (np->repflow) 683 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb)); 684 if (ipv6_opt_accepted(sk, opt_skb, 685 &DCCP_SKB_CB(opt_skb)->header.h6)) { 686 memmove(IP6CB(opt_skb), 687 &DCCP_SKB_CB(opt_skb)->header.h6, 688 sizeof(struct inet6_skb_parm)); 689 opt_skb = xchg(&np->pktoptions, opt_skb); 690 } else { 691 __kfree_skb(opt_skb); 692 opt_skb = xchg(&np->pktoptions, NULL); 693 } 694 } 695 696 kfree_skb(opt_skb); 697 return 0; 698 } 699 700 static int dccp_v6_rcv(struct sk_buff *skb) 701 { 702 const struct dccp_hdr *dh; 703 bool refcounted; 704 struct sock *sk; 705 int min_cov; 706 707 /* Step 1: Check header basics */ 708 709 if (dccp_invalid_packet(skb)) 710 goto discard_it; 711 712 /* Step 1: If header checksum is incorrect, drop packet and return. */ 713 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, 714 &ipv6_hdr(skb)->daddr)) { 715 DCCP_WARN("dropped packet with invalid checksum\n"); 716 goto discard_it; 717 } 718 719 dh = dccp_hdr(skb); 720 721 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); 722 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; 723 724 if (dccp_packet_without_ack(skb)) 725 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; 726 else 727 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); 728 729 lookup: 730 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), 731 dh->dccph_sport, dh->dccph_dport, 732 inet6_iif(skb), 0, &refcounted); 733 if (!sk) { 734 dccp_pr_debug("failed to look up flow ID in table and " 735 "get corresponding socket\n"); 736 goto no_dccp_socket; 737 } 738 739 /* 740 * Step 2: 741 * ... or S.state == TIMEWAIT, 742 * Generate Reset(No Connection) unless P.type == Reset 743 * Drop packet and return 744 */ 745 if (sk->sk_state == DCCP_TIME_WAIT) { 746 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); 747 inet_twsk_put(inet_twsk(sk)); 748 goto no_dccp_socket; 749 } 750 751 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 752 struct request_sock *req = inet_reqsk(sk); 753 struct sock *nsk; 754 755 sk = req->rsk_listener; 756 if (unlikely(sk->sk_state != DCCP_LISTEN)) { 757 inet_csk_reqsk_queue_drop_and_put(sk, req); 758 goto lookup; 759 } 760 sock_hold(sk); 761 refcounted = true; 762 nsk = dccp_check_req(sk, skb, req); 763 if (!nsk) { 764 reqsk_put(req); 765 goto discard_and_relse; 766 } 767 if (nsk == sk) { 768 reqsk_put(req); 769 } else if (dccp_child_process(sk, nsk, skb)) { 770 dccp_v6_ctl_send_reset(sk, skb); 771 goto discard_and_relse; 772 } else { 773 sock_put(sk); 774 return 0; 775 } 776 } 777 /* 778 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage 779 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted 780 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov 781 */ 782 min_cov = dccp_sk(sk)->dccps_pcrlen; 783 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { 784 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", 785 dh->dccph_cscov, min_cov); 786 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ 787 goto discard_and_relse; 788 } 789 790 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 791 goto discard_and_relse; 792 nf_reset_ct(skb); 793 794 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, 795 refcounted) ? -1 : 0; 796 797 no_dccp_socket: 798 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 799 goto discard_it; 800 /* 801 * Step 2: 802 * If no socket ... 803 * Generate Reset(No Connection) unless P.type == Reset 804 * Drop packet and return 805 */ 806 if (dh->dccph_type != DCCP_PKT_RESET) { 807 DCCP_SKB_CB(skb)->dccpd_reset_code = 808 DCCP_RESET_CODE_NO_CONNECTION; 809 dccp_v6_ctl_send_reset(sk, skb); 810 } 811 812 discard_it: 813 kfree_skb(skb); 814 return 0; 815 816 discard_and_relse: 817 if (refcounted) 818 sock_put(sk); 819 goto discard_it; 820 } 821 822 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 823 int addr_len) 824 { 825 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 826 struct inet_connection_sock *icsk = inet_csk(sk); 827 struct inet_sock *inet = inet_sk(sk); 828 struct ipv6_pinfo *np = inet6_sk(sk); 829 struct dccp_sock *dp = dccp_sk(sk); 830 struct in6_addr *saddr = NULL, *final_p, final; 831 struct ipv6_txoptions *opt; 832 struct flowi6 fl6; 833 struct dst_entry *dst; 834 int addr_type; 835 int err; 836 837 dp->dccps_role = DCCP_ROLE_CLIENT; 838 839 if (addr_len < SIN6_LEN_RFC2133) 840 return -EINVAL; 841 842 if (usin->sin6_family != AF_INET6) 843 return -EAFNOSUPPORT; 844 845 memset(&fl6, 0, sizeof(fl6)); 846 847 if (np->sndflow) { 848 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 849 IP6_ECN_flow_init(fl6.flowlabel); 850 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 851 struct ip6_flowlabel *flowlabel; 852 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 853 if (IS_ERR(flowlabel)) 854 return -EINVAL; 855 fl6_sock_release(flowlabel); 856 } 857 } 858 /* 859 * connect() to INADDR_ANY means loopback (BSD'ism). 860 */ 861 if (ipv6_addr_any(&usin->sin6_addr)) 862 usin->sin6_addr.s6_addr[15] = 1; 863 864 addr_type = ipv6_addr_type(&usin->sin6_addr); 865 866 if (addr_type & IPV6_ADDR_MULTICAST) 867 return -ENETUNREACH; 868 869 if (addr_type & IPV6_ADDR_LINKLOCAL) { 870 if (addr_len >= sizeof(struct sockaddr_in6) && 871 usin->sin6_scope_id) { 872 /* If interface is set while binding, indices 873 * must coincide. 874 */ 875 if (sk->sk_bound_dev_if && 876 sk->sk_bound_dev_if != usin->sin6_scope_id) 877 return -EINVAL; 878 879 sk->sk_bound_dev_if = usin->sin6_scope_id; 880 } 881 882 /* Connect to link-local address requires an interface */ 883 if (!sk->sk_bound_dev_if) 884 return -EINVAL; 885 } 886 887 sk->sk_v6_daddr = usin->sin6_addr; 888 np->flow_label = fl6.flowlabel; 889 890 /* 891 * DCCP over IPv4 892 */ 893 if (addr_type == IPV6_ADDR_MAPPED) { 894 u32 exthdrlen = icsk->icsk_ext_hdr_len; 895 struct sockaddr_in sin; 896 897 SOCK_DEBUG(sk, "connect: ipv4 mapped\n"); 898 899 if (ipv6_only_sock(sk)) 900 return -ENETUNREACH; 901 902 sin.sin_family = AF_INET; 903 sin.sin_port = usin->sin6_port; 904 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 905 906 icsk->icsk_af_ops = &dccp_ipv6_mapped; 907 sk->sk_backlog_rcv = dccp_v4_do_rcv; 908 909 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 910 if (err) { 911 icsk->icsk_ext_hdr_len = exthdrlen; 912 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 913 sk->sk_backlog_rcv = dccp_v6_do_rcv; 914 goto failure; 915 } 916 np->saddr = sk->sk_v6_rcv_saddr; 917 return err; 918 } 919 920 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 921 saddr = &sk->sk_v6_rcv_saddr; 922 923 fl6.flowi6_proto = IPPROTO_DCCP; 924 fl6.daddr = sk->sk_v6_daddr; 925 fl6.saddr = saddr ? *saddr : np->saddr; 926 fl6.flowi6_oif = sk->sk_bound_dev_if; 927 fl6.fl6_dport = usin->sin6_port; 928 fl6.fl6_sport = inet->inet_sport; 929 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 930 931 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 932 final_p = fl6_update_dst(&fl6, opt, &final); 933 934 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 935 if (IS_ERR(dst)) { 936 err = PTR_ERR(dst); 937 goto failure; 938 } 939 940 if (saddr == NULL) { 941 saddr = &fl6.saddr; 942 943 err = inet_bhash2_update_saddr(sk, saddr, AF_INET6); 944 if (err) 945 goto failure; 946 } 947 948 /* set the source address */ 949 np->saddr = *saddr; 950 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 951 952 ip6_dst_store(sk, dst, NULL, NULL); 953 954 icsk->icsk_ext_hdr_len = 0; 955 if (opt) 956 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; 957 958 inet->inet_dport = usin->sin6_port; 959 960 dccp_set_state(sk, DCCP_REQUESTING); 961 err = inet6_hash_connect(&dccp_death_row, sk); 962 if (err) 963 goto late_failure; 964 965 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 966 sk->sk_v6_daddr.s6_addr32, 967 inet->inet_sport, 968 inet->inet_dport); 969 err = dccp_connect(sk); 970 if (err) 971 goto late_failure; 972 973 return 0; 974 975 late_failure: 976 dccp_set_state(sk, DCCP_CLOSED); 977 inet_bhash2_reset_saddr(sk); 978 __sk_dst_reset(sk); 979 failure: 980 inet->inet_dport = 0; 981 sk->sk_route_caps = 0; 982 return err; 983 } 984 985 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 986 .queue_xmit = inet6_csk_xmit, 987 .send_check = dccp_v6_send_check, 988 .rebuild_header = inet6_sk_rebuild_header, 989 .conn_request = dccp_v6_conn_request, 990 .syn_recv_sock = dccp_v6_request_recv_sock, 991 .net_header_len = sizeof(struct ipv6hdr), 992 .setsockopt = ipv6_setsockopt, 993 .getsockopt = ipv6_getsockopt, 994 .addr2sockaddr = inet6_csk_addr2sockaddr, 995 .sockaddr_len = sizeof(struct sockaddr_in6), 996 }; 997 998 /* 999 * DCCP over IPv4 via INET6 API 1000 */ 1001 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 1002 .queue_xmit = ip_queue_xmit, 1003 .send_check = dccp_v4_send_check, 1004 .rebuild_header = inet_sk_rebuild_header, 1005 .conn_request = dccp_v6_conn_request, 1006 .syn_recv_sock = dccp_v6_request_recv_sock, 1007 .net_header_len = sizeof(struct iphdr), 1008 .setsockopt = ipv6_setsockopt, 1009 .getsockopt = ipv6_getsockopt, 1010 .addr2sockaddr = inet6_csk_addr2sockaddr, 1011 .sockaddr_len = sizeof(struct sockaddr_in6), 1012 }; 1013 1014 static void dccp_v6_sk_destruct(struct sock *sk) 1015 { 1016 dccp_destruct_common(sk); 1017 inet6_sock_destruct(sk); 1018 } 1019 1020 /* NOTE: A lot of things set to zero explicitly by call to 1021 * sk_alloc() so need not be done here. 1022 */ 1023 static int dccp_v6_init_sock(struct sock *sk) 1024 { 1025 static __u8 dccp_v6_ctl_sock_initialized; 1026 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 1027 1028 if (err == 0) { 1029 if (unlikely(!dccp_v6_ctl_sock_initialized)) 1030 dccp_v6_ctl_sock_initialized = 1; 1031 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 1032 sk->sk_destruct = dccp_v6_sk_destruct; 1033 } 1034 1035 return err; 1036 } 1037 1038 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 1039 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 1040 }; 1041 1042 static struct proto dccp_v6_prot = { 1043 .name = "DCCPv6", 1044 .owner = THIS_MODULE, 1045 .close = dccp_close, 1046 .connect = dccp_v6_connect, 1047 .disconnect = dccp_disconnect, 1048 .ioctl = dccp_ioctl, 1049 .init = dccp_v6_init_sock, 1050 .setsockopt = dccp_setsockopt, 1051 .getsockopt = dccp_getsockopt, 1052 .sendmsg = dccp_sendmsg, 1053 .recvmsg = dccp_recvmsg, 1054 .backlog_rcv = dccp_v6_do_rcv, 1055 .hash = inet6_hash, 1056 .unhash = inet_unhash, 1057 .accept = inet_csk_accept, 1058 .get_port = inet_csk_get_port, 1059 .shutdown = dccp_shutdown, 1060 .destroy = dccp_destroy_sock, 1061 .orphan_count = &dccp_orphan_count, 1062 .max_header = MAX_DCCP_HEADER, 1063 .obj_size = sizeof(struct dccp6_sock), 1064 .ipv6_pinfo_offset = offsetof(struct dccp6_sock, inet6), 1065 .slab_flags = SLAB_TYPESAFE_BY_RCU, 1066 .rsk_prot = &dccp6_request_sock_ops, 1067 .twsk_prot = &dccp6_timewait_sock_ops, 1068 .h.hashinfo = &dccp_hashinfo, 1069 }; 1070 1071 static const struct inet6_protocol dccp_v6_protocol = { 1072 .handler = dccp_v6_rcv, 1073 .err_handler = dccp_v6_err, 1074 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1075 }; 1076 1077 static const struct proto_ops inet6_dccp_ops = { 1078 .family = PF_INET6, 1079 .owner = THIS_MODULE, 1080 .release = inet6_release, 1081 .bind = inet6_bind, 1082 .connect = inet_stream_connect, 1083 .socketpair = sock_no_socketpair, 1084 .accept = inet_accept, 1085 .getname = inet6_getname, 1086 .poll = dccp_poll, 1087 .ioctl = inet6_ioctl, 1088 .gettstamp = sock_gettstamp, 1089 .listen = inet_dccp_listen, 1090 .shutdown = inet_shutdown, 1091 .setsockopt = sock_common_setsockopt, 1092 .getsockopt = sock_common_getsockopt, 1093 .sendmsg = inet_sendmsg, 1094 .recvmsg = sock_common_recvmsg, 1095 .mmap = sock_no_mmap, 1096 #ifdef CONFIG_COMPAT 1097 .compat_ioctl = inet6_compat_ioctl, 1098 #endif 1099 }; 1100 1101 static struct inet_protosw dccp_v6_protosw = { 1102 .type = SOCK_DCCP, 1103 .protocol = IPPROTO_DCCP, 1104 .prot = &dccp_v6_prot, 1105 .ops = &inet6_dccp_ops, 1106 .flags = INET_PROTOSW_ICSK, 1107 }; 1108 1109 static int __net_init dccp_v6_init_net(struct net *net) 1110 { 1111 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id); 1112 1113 if (dccp_hashinfo.bhash == NULL) 1114 return -ESOCKTNOSUPPORT; 1115 1116 return inet_ctl_sock_create(&pn->v6_ctl_sk, PF_INET6, 1117 SOCK_DCCP, IPPROTO_DCCP, net); 1118 } 1119 1120 static void __net_exit dccp_v6_exit_net(struct net *net) 1121 { 1122 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id); 1123 1124 inet_ctl_sock_destroy(pn->v6_ctl_sk); 1125 } 1126 1127 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list) 1128 { 1129 inet_twsk_purge(&dccp_hashinfo, AF_INET6); 1130 } 1131 1132 static struct pernet_operations dccp_v6_ops = { 1133 .init = dccp_v6_init_net, 1134 .exit = dccp_v6_exit_net, 1135 .exit_batch = dccp_v6_exit_batch, 1136 .id = &dccp_v6_pernet_id, 1137 .size = sizeof(struct dccp_v6_pernet), 1138 }; 1139 1140 static int __init dccp_v6_init(void) 1141 { 1142 int err = proto_register(&dccp_v6_prot, 1); 1143 1144 if (err) 1145 goto out; 1146 1147 inet6_register_protosw(&dccp_v6_protosw); 1148 1149 err = register_pernet_subsys(&dccp_v6_ops); 1150 if (err) 1151 goto out_destroy_ctl_sock; 1152 1153 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1154 if (err) 1155 goto out_unregister_proto; 1156 1157 out: 1158 return err; 1159 out_unregister_proto: 1160 unregister_pernet_subsys(&dccp_v6_ops); 1161 out_destroy_ctl_sock: 1162 inet6_unregister_protosw(&dccp_v6_protosw); 1163 proto_unregister(&dccp_v6_prot); 1164 goto out; 1165 } 1166 1167 static void __exit dccp_v6_exit(void) 1168 { 1169 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1170 unregister_pernet_subsys(&dccp_v6_ops); 1171 inet6_unregister_protosw(&dccp_v6_protosw); 1172 proto_unregister(&dccp_v6_prot); 1173 } 1174 1175 module_init(dccp_v6_init); 1176 module_exit(dccp_v6_exit); 1177 1178 /* 1179 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) 1180 * values directly, Also cover the case where the protocol is not specified, 1181 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP 1182 */ 1183 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6); 1184 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6); 1185 MODULE_LICENSE("GPL"); 1186 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>"); 1187 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol"); 1188