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 #include <net/rstreason.h> 33 34 #include "dccp.h" 35 #include "ipv6.h" 36 #include "feat.h" 37 38 struct dccp_v6_pernet { 39 struct sock *v6_ctl_sk; 40 }; 41 42 static unsigned int dccp_v6_pernet_id __read_mostly; 43 44 /* The per-net v6_ctl_sk is used for sending RSTs and ACKs */ 45 46 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped; 47 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops; 48 49 /* add pseudo-header to DCCP checksum stored in skb->csum */ 50 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb, 51 const struct in6_addr *saddr, 52 const struct in6_addr *daddr) 53 { 54 return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum); 55 } 56 57 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb) 58 { 59 struct ipv6_pinfo *np = inet6_sk(sk); 60 struct dccp_hdr *dh = dccp_hdr(skb); 61 62 dccp_csum_outgoing(skb); 63 dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr); 64 } 65 66 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb) 67 { 68 return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32, 69 ipv6_hdr(skb)->saddr.s6_addr32, 70 dccp_hdr(skb)->dccph_dport, 71 dccp_hdr(skb)->dccph_sport ); 72 73 } 74 75 static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 76 u8 type, u8 code, int offset, __be32 info) 77 { 78 const struct ipv6hdr *hdr; 79 const struct dccp_hdr *dh; 80 struct dccp_sock *dp; 81 struct ipv6_pinfo *np; 82 struct sock *sk; 83 int err; 84 __u64 seq; 85 struct net *net = dev_net(skb->dev); 86 87 if (!pskb_may_pull(skb, offset + sizeof(*dh))) 88 return -EINVAL; 89 dh = (struct dccp_hdr *)(skb->data + offset); 90 if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh))) 91 return -EINVAL; 92 hdr = (const struct ipv6hdr *)skb->data; 93 dh = (struct dccp_hdr *)(skb->data + offset); 94 95 sk = __inet6_lookup_established(net, &dccp_hashinfo, 96 &hdr->daddr, dh->dccph_dport, 97 &hdr->saddr, ntohs(dh->dccph_sport), 98 inet6_iif(skb), 0); 99 100 if (!sk) { 101 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), 102 ICMP6_MIB_INERRORS); 103 return -ENOENT; 104 } 105 106 if (sk->sk_state == DCCP_TIME_WAIT) { 107 inet_twsk_put(inet_twsk(sk)); 108 return 0; 109 } 110 seq = dccp_hdr_seq(dh); 111 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 112 dccp_req_err(sk, seq); 113 return 0; 114 } 115 116 bh_lock_sock(sk); 117 if (sock_owned_by_user(sk)) 118 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 119 120 if (sk->sk_state == DCCP_CLOSED) 121 goto out; 122 123 dp = dccp_sk(sk); 124 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) && 125 !between48(seq, dp->dccps_awl, dp->dccps_awh)) { 126 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 127 goto out; 128 } 129 130 np = inet6_sk(sk); 131 132 if (type == NDISC_REDIRECT) { 133 if (!sock_owned_by_user(sk)) { 134 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie); 135 136 if (dst) 137 dst->ops->redirect(dst, sk, skb); 138 } 139 goto out; 140 } 141 142 if (type == ICMPV6_PKT_TOOBIG) { 143 struct dst_entry *dst = NULL; 144 145 if (!ip6_sk_accept_pmtu(sk)) 146 goto out; 147 148 if (sock_owned_by_user(sk)) 149 goto out; 150 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED)) 151 goto out; 152 153 dst = inet6_csk_update_pmtu(sk, ntohl(info)); 154 if (!dst) 155 goto out; 156 157 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) 158 dccp_sync_mss(sk, dst_mtu(dst)); 159 goto out; 160 } 161 162 icmpv6_err_convert(type, code, &err); 163 164 /* Might be for an request_sock */ 165 switch (sk->sk_state) { 166 case DCCP_REQUESTING: 167 case DCCP_RESPOND: /* Cannot happen. 168 It can, it SYNs are crossed. --ANK */ 169 if (!sock_owned_by_user(sk)) { 170 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 171 sk->sk_err = err; 172 /* 173 * Wake people up to see the error 174 * (see connect in sock.c) 175 */ 176 sk_error_report(sk); 177 dccp_done(sk); 178 } else { 179 WRITE_ONCE(sk->sk_err_soft, err); 180 } 181 goto out; 182 } 183 184 if (!sock_owned_by_user(sk) && inet6_test_bit(RECVERR6, sk)) { 185 sk->sk_err = err; 186 sk_error_report(sk); 187 } else { 188 WRITE_ONCE(sk->sk_err_soft, err); 189 } 190 out: 191 bh_unlock_sock(sk); 192 sock_put(sk); 193 return 0; 194 } 195 196 197 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req) 198 { 199 struct inet_request_sock *ireq = inet_rsk(req); 200 struct ipv6_pinfo *np = inet6_sk(sk); 201 struct sk_buff *skb; 202 struct in6_addr *final_p, final; 203 struct flowi6 fl6; 204 int err = -1; 205 struct dst_entry *dst; 206 207 memset(&fl6, 0, sizeof(fl6)); 208 fl6.flowi6_proto = IPPROTO_DCCP; 209 fl6.daddr = ireq->ir_v6_rmt_addr; 210 fl6.saddr = ireq->ir_v6_loc_addr; 211 fl6.flowlabel = 0; 212 fl6.flowi6_oif = ireq->ir_iif; 213 fl6.fl6_dport = ireq->ir_rmt_port; 214 fl6.fl6_sport = htons(ireq->ir_num); 215 security_req_classify_flow(req, flowi6_to_flowi_common(&fl6)); 216 217 218 rcu_read_lock(); 219 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final); 220 rcu_read_unlock(); 221 222 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 223 if (IS_ERR(dst)) { 224 err = PTR_ERR(dst); 225 dst = NULL; 226 goto done; 227 } 228 229 skb = dccp_make_response(sk, dst, req); 230 if (skb != NULL) { 231 struct dccp_hdr *dh = dccp_hdr(skb); 232 struct ipv6_txoptions *opt; 233 234 dh->dccph_checksum = dccp_v6_csum_finish(skb, 235 &ireq->ir_v6_loc_addr, 236 &ireq->ir_v6_rmt_addr); 237 fl6.daddr = ireq->ir_v6_rmt_addr; 238 rcu_read_lock(); 239 opt = ireq->ipv6_opt; 240 if (!opt) 241 opt = rcu_dereference(np->opt); 242 err = ip6_xmit(sk, skb, &fl6, READ_ONCE(sk->sk_mark), opt, 243 np->tclass, READ_ONCE(sk->sk_priority)); 244 rcu_read_unlock(); 245 err = net_xmit_eval(err); 246 } 247 248 done: 249 dst_release(dst); 250 return err; 251 } 252 253 static void dccp_v6_reqsk_destructor(struct request_sock *req) 254 { 255 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); 256 kfree(inet_rsk(req)->ipv6_opt); 257 kfree_skb(inet_rsk(req)->pktopts); 258 } 259 260 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb, 261 enum sk_rst_reason reason) 262 { 263 const struct ipv6hdr *rxip6h; 264 struct sk_buff *skb; 265 struct flowi6 fl6; 266 struct net *net = dev_net(skb_dst(rxskb)->dev); 267 struct dccp_v6_pernet *pn; 268 struct sock *ctl_sk; 269 struct dst_entry *dst; 270 271 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) 272 return; 273 274 if (!ipv6_unicast_destination(rxskb)) 275 return; 276 277 pn = net_generic(net, dccp_v6_pernet_id); 278 ctl_sk = pn->v6_ctl_sk; 279 skb = dccp_ctl_make_reset(ctl_sk, rxskb); 280 if (skb == NULL) 281 return; 282 283 rxip6h = ipv6_hdr(rxskb); 284 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr, 285 &rxip6h->daddr); 286 287 memset(&fl6, 0, sizeof(fl6)); 288 fl6.daddr = rxip6h->saddr; 289 fl6.saddr = rxip6h->daddr; 290 291 fl6.flowi6_proto = IPPROTO_DCCP; 292 fl6.flowi6_oif = inet6_iif(rxskb); 293 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport; 294 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport; 295 security_skb_classify_flow(rxskb, flowi6_to_flowi_common(&fl6)); 296 297 /* sk = NULL, but it is safe for now. RST socket required. */ 298 dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL); 299 if (!IS_ERR(dst)) { 300 skb_dst_set(skb, dst); 301 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0, 0); 302 DCCP_INC_STATS(DCCP_MIB_OUTSEGS); 303 DCCP_INC_STATS(DCCP_MIB_OUTRSTS); 304 return; 305 } 306 307 kfree_skb(skb); 308 } 309 310 static struct request_sock_ops dccp6_request_sock_ops = { 311 .family = AF_INET6, 312 .obj_size = sizeof(struct dccp6_request_sock), 313 .rtx_syn_ack = dccp_v6_send_response, 314 .send_ack = dccp_reqsk_send_ack, 315 .destructor = dccp_v6_reqsk_destructor, 316 .send_reset = dccp_v6_ctl_send_reset, 317 .syn_ack_timeout = dccp_syn_ack_timeout, 318 }; 319 320 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 321 { 322 struct request_sock *req; 323 struct dccp_request_sock *dreq; 324 struct inet_request_sock *ireq; 325 struct ipv6_pinfo *np = inet6_sk(sk); 326 const __be32 service = dccp_hdr_request(skb)->dccph_req_service; 327 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); 328 329 if (skb->protocol == htons(ETH_P_IP)) 330 return dccp_v4_conn_request(sk, skb); 331 332 if (!ipv6_unicast_destination(skb)) 333 return 0; /* discard, don't send a reset here */ 334 335 if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { 336 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); 337 return 0; 338 } 339 340 if (dccp_bad_service_code(sk, service)) { 341 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; 342 goto drop; 343 } 344 /* 345 * There are no SYN attacks on IPv6, yet... 346 */ 347 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 348 if (inet_csk_reqsk_queue_is_full(sk)) 349 goto drop; 350 351 if (sk_acceptq_is_full(sk)) 352 goto drop; 353 354 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true); 355 if (req == NULL) 356 goto drop; 357 358 if (dccp_reqsk_init(req, dccp_sk(sk), skb)) 359 goto drop_and_free; 360 361 dreq = dccp_rsk(req); 362 if (dccp_parse_options(sk, dreq, skb)) 363 goto drop_and_free; 364 365 ireq = inet_rsk(req); 366 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; 367 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; 368 ireq->ireq_family = AF_INET6; 369 ireq->ir_mark = inet_request_mark(sk, skb); 370 371 if (security_inet_conn_request(sk, skb, req)) 372 goto drop_and_free; 373 374 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) || 375 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || 376 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { 377 refcount_inc(&skb->users); 378 ireq->pktopts = skb; 379 } 380 ireq->ir_iif = READ_ONCE(sk->sk_bound_dev_if); 381 382 /* So that link locals have meaning */ 383 if (!ireq->ir_iif && 384 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 385 ireq->ir_iif = inet6_iif(skb); 386 387 /* 388 * Step 3: Process LISTEN state 389 * 390 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 391 * 392 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 393 */ 394 dreq->dreq_isr = dcb->dccpd_seq; 395 dreq->dreq_gsr = dreq->dreq_isr; 396 dreq->dreq_iss = dccp_v6_init_sequence(skb); 397 dreq->dreq_gss = dreq->dreq_iss; 398 dreq->dreq_service = service; 399 400 if (dccp_v6_send_response(sk, req)) 401 goto drop_and_free; 402 403 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 404 reqsk_put(req); 405 return 0; 406 407 drop_and_free: 408 reqsk_free(req); 409 drop: 410 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 411 return -1; 412 } 413 414 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 415 struct sk_buff *skb, 416 struct request_sock *req, 417 struct dst_entry *dst, 418 struct request_sock *req_unhash, 419 bool *own_req) 420 { 421 struct inet_request_sock *ireq = inet_rsk(req); 422 struct ipv6_pinfo *newnp; 423 const struct ipv6_pinfo *np = inet6_sk(sk); 424 struct ipv6_txoptions *opt; 425 struct inet_sock *newinet; 426 struct dccp6_sock *newdp6; 427 struct sock *newsk; 428 429 if (skb->protocol == htons(ETH_P_IP)) { 430 /* 431 * v6 mapped 432 */ 433 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 434 req_unhash, own_req); 435 if (newsk == NULL) 436 return NULL; 437 438 newdp6 = (struct dccp6_sock *)newsk; 439 newinet = inet_sk(newsk); 440 newinet->pinet6 = &newdp6->inet6; 441 newnp = inet6_sk(newsk); 442 443 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 444 445 newnp->saddr = newsk->sk_v6_rcv_saddr; 446 447 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 448 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 449 newnp->pktoptions = NULL; 450 newnp->opt = NULL; 451 newnp->ipv6_mc_list = NULL; 452 newnp->ipv6_ac_list = NULL; 453 newnp->ipv6_fl_list = NULL; 454 newnp->mcast_oif = inet_iif(skb); 455 newnp->mcast_hops = ip_hdr(skb)->ttl; 456 457 /* 458 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 459 * here, dccp_create_openreq_child now does this for us, see the comment in 460 * that function for the gory details. -acme 461 */ 462 463 /* It is tricky place. Until this moment IPv4 tcp 464 worked with IPv6 icsk.icsk_af_ops. 465 Sync it now. 466 */ 467 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 468 469 return newsk; 470 } 471 472 473 if (sk_acceptq_is_full(sk)) 474 goto out_overflow; 475 476 if (!dst) { 477 struct flowi6 fl6; 478 479 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 480 if (!dst) 481 goto out; 482 } 483 484 newsk = dccp_create_openreq_child(sk, req, skb); 485 if (newsk == NULL) 486 goto out_nonewsk; 487 488 /* 489 * No need to charge this sock to the relevant IPv6 refcnt debug socks 490 * count here, dccp_create_openreq_child now does this for us, see the 491 * comment in that function for the gory details. -acme 492 */ 493 494 ip6_dst_store(newsk, dst, NULL, NULL); 495 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 496 NETIF_F_TSO); 497 newdp6 = (struct dccp6_sock *)newsk; 498 newinet = inet_sk(newsk); 499 newinet->pinet6 = &newdp6->inet6; 500 newnp = inet6_sk(newsk); 501 502 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 503 504 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 505 newnp->saddr = ireq->ir_v6_loc_addr; 506 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 507 newsk->sk_bound_dev_if = ireq->ir_iif; 508 509 /* Now IPv6 options... 510 511 First: no IPv4 options. 512 */ 513 newinet->inet_opt = NULL; 514 515 /* Clone RX bits */ 516 newnp->rxopt.all = np->rxopt.all; 517 518 newnp->ipv6_mc_list = NULL; 519 newnp->ipv6_ac_list = NULL; 520 newnp->ipv6_fl_list = NULL; 521 newnp->pktoptions = NULL; 522 newnp->opt = NULL; 523 newnp->mcast_oif = inet6_iif(skb); 524 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 525 526 /* 527 * Clone native IPv6 options from listening socket (if any) 528 * 529 * Yes, keeping reference count would be much more clever, but we make 530 * one more one thing there: reattach optmem to newsk. 531 */ 532 opt = ireq->ipv6_opt; 533 if (!opt) 534 opt = rcu_dereference(np->opt); 535 if (opt) { 536 opt = ipv6_dup_options(newsk, opt); 537 RCU_INIT_POINTER(newnp->opt, opt); 538 } 539 inet_csk(newsk)->icsk_ext_hdr_len = 0; 540 if (opt) 541 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 542 opt->opt_flen; 543 544 dccp_sync_mss(newsk, dst_mtu(dst)); 545 546 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 547 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 548 549 if (__inet_inherit_port(sk, newsk) < 0) { 550 inet_csk_prepare_forced_close(newsk); 551 dccp_done(newsk); 552 goto out; 553 } 554 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL); 555 /* Clone pktoptions received with SYN, if we own the req */ 556 if (*own_req && ireq->pktopts) { 557 newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk); 558 consume_skb(ireq->pktopts); 559 ireq->pktopts = NULL; 560 } 561 562 return newsk; 563 564 out_overflow: 565 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 566 out_nonewsk: 567 dst_release(dst); 568 out: 569 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 570 return NULL; 571 } 572 573 /* The socket must have it's spinlock held when we get 574 * here. 575 * 576 * We have a potential double-lock case here, so even when 577 * doing backlog processing we use the BH locking scheme. 578 * This is because we cannot sleep with the original spinlock 579 * held. 580 */ 581 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 582 { 583 struct ipv6_pinfo *np = inet6_sk(sk); 584 struct sk_buff *opt_skb = NULL; 585 586 /* Imagine: socket is IPv6. IPv4 packet arrives, 587 goes to IPv4 receive handler and backlogged. 588 From backlog it always goes here. Kerboom... 589 Fortunately, dccp_rcv_established and rcv_established 590 handle them correctly, but it is not case with 591 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 592 */ 593 594 if (skb->protocol == htons(ETH_P_IP)) 595 return dccp_v4_do_rcv(sk, skb); 596 597 if (sk_filter(sk, skb)) 598 goto discard; 599 600 /* 601 * socket locking is here for SMP purposes as backlog rcv is currently 602 * called with bh processing disabled. 603 */ 604 605 /* Do Stevens' IPV6_PKTOPTIONS. 606 607 Yes, guys, it is the only place in our code, where we 608 may make it not affecting IPv4. 609 The rest of code is protocol independent, 610 and I do not like idea to uglify IPv4. 611 612 Actually, all the idea behind IPV6_PKTOPTIONS 613 looks not very well thought. For now we latch 614 options, received in the last packet, enqueued 615 by tcp. Feel free to propose better solution. 616 --ANK (980728) 617 */ 618 if (np->rxopt.all) 619 opt_skb = skb_clone_and_charge_r(skb, sk); 620 621 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 622 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 623 goto reset; 624 if (opt_skb) 625 goto ipv6_pktoptions; 626 return 0; 627 } 628 629 /* 630 * Step 3: Process LISTEN state 631 * If S.state == LISTEN, 632 * If P.type == Request or P contains a valid Init Cookie option, 633 * (* Must scan the packet's options to check for Init 634 * Cookies. Only Init Cookies are processed here, 635 * however; other options are processed in Step 8. This 636 * scan need only be performed if the endpoint uses Init 637 * Cookies *) 638 * (* Generate a new socket and switch to that socket *) 639 * Set S := new socket for this port pair 640 * S.state = RESPOND 641 * Choose S.ISS (initial seqno) or set from Init Cookies 642 * Initialize S.GAR := S.ISS 643 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 644 * Continue with S.state == RESPOND 645 * (* A Response packet will be generated in Step 11 *) 646 * Otherwise, 647 * Generate Reset(No Connection) unless P.type == Reset 648 * Drop packet and return 649 * 650 * NOTE: the check for the packet types is done in 651 * dccp_rcv_state_process 652 */ 653 654 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 655 goto reset; 656 if (opt_skb) 657 goto ipv6_pktoptions; 658 return 0; 659 660 reset: 661 dccp_v6_ctl_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED); 662 discard: 663 if (opt_skb != NULL) 664 __kfree_skb(opt_skb); 665 kfree_skb(skb); 666 return 0; 667 668 /* Handling IPV6_PKTOPTIONS skb the similar 669 * way it's done for net/ipv6/tcp_ipv6.c 670 */ 671 ipv6_pktoptions: 672 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) { 673 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) 674 WRITE_ONCE(np->mcast_oif, inet6_iif(opt_skb)); 675 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) 676 WRITE_ONCE(np->mcast_hops, ipv6_hdr(opt_skb)->hop_limit); 677 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) 678 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); 679 if (inet6_test_bit(REPFLOW, sk)) 680 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb)); 681 if (ipv6_opt_accepted(sk, opt_skb, 682 &DCCP_SKB_CB(opt_skb)->header.h6)) { 683 memmove(IP6CB(opt_skb), 684 &DCCP_SKB_CB(opt_skb)->header.h6, 685 sizeof(struct inet6_skb_parm)); 686 opt_skb = xchg(&np->pktoptions, opt_skb); 687 } else { 688 __kfree_skb(opt_skb); 689 opt_skb = xchg(&np->pktoptions, NULL); 690 } 691 } 692 693 kfree_skb(opt_skb); 694 return 0; 695 } 696 697 static int dccp_v6_rcv(struct sk_buff *skb) 698 { 699 const struct dccp_hdr *dh; 700 bool refcounted; 701 struct sock *sk; 702 int min_cov; 703 704 /* Step 1: Check header basics */ 705 706 if (dccp_invalid_packet(skb)) 707 goto discard_it; 708 709 /* Step 1: If header checksum is incorrect, drop packet and return. */ 710 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, 711 &ipv6_hdr(skb)->daddr)) { 712 DCCP_WARN("dropped packet with invalid checksum\n"); 713 goto discard_it; 714 } 715 716 dh = dccp_hdr(skb); 717 718 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); 719 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; 720 721 if (dccp_packet_without_ack(skb)) 722 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; 723 else 724 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); 725 726 lookup: 727 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), 728 dh->dccph_sport, dh->dccph_dport, 729 inet6_iif(skb), 0, &refcounted); 730 if (!sk) { 731 dccp_pr_debug("failed to look up flow ID in table and " 732 "get corresponding socket\n"); 733 goto no_dccp_socket; 734 } 735 736 /* 737 * Step 2: 738 * ... or S.state == TIMEWAIT, 739 * Generate Reset(No Connection) unless P.type == Reset 740 * Drop packet and return 741 */ 742 if (sk->sk_state == DCCP_TIME_WAIT) { 743 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); 744 inet_twsk_put(inet_twsk(sk)); 745 goto no_dccp_socket; 746 } 747 748 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 749 struct request_sock *req = inet_reqsk(sk); 750 struct sock *nsk; 751 752 sk = req->rsk_listener; 753 if (unlikely(sk->sk_state != DCCP_LISTEN)) { 754 inet_csk_reqsk_queue_drop_and_put(sk, req); 755 goto lookup; 756 } 757 sock_hold(sk); 758 refcounted = true; 759 nsk = dccp_check_req(sk, skb, req); 760 if (!nsk) { 761 reqsk_put(req); 762 goto discard_and_relse; 763 } 764 if (nsk == sk) { 765 reqsk_put(req); 766 } else if (dccp_child_process(sk, nsk, skb)) { 767 dccp_v6_ctl_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED); 768 goto discard_and_relse; 769 } else { 770 sock_put(sk); 771 return 0; 772 } 773 } 774 /* 775 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage 776 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted 777 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov 778 */ 779 min_cov = dccp_sk(sk)->dccps_pcrlen; 780 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { 781 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", 782 dh->dccph_cscov, min_cov); 783 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ 784 goto discard_and_relse; 785 } 786 787 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 788 goto discard_and_relse; 789 nf_reset_ct(skb); 790 791 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, 792 refcounted) ? -1 : 0; 793 794 no_dccp_socket: 795 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 796 goto discard_it; 797 /* 798 * Step 2: 799 * If no socket ... 800 * Generate Reset(No Connection) unless P.type == Reset 801 * Drop packet and return 802 */ 803 if (dh->dccph_type != DCCP_PKT_RESET) { 804 DCCP_SKB_CB(skb)->dccpd_reset_code = 805 DCCP_RESET_CODE_NO_CONNECTION; 806 dccp_v6_ctl_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED); 807 } 808 809 discard_it: 810 kfree_skb(skb); 811 return 0; 812 813 discard_and_relse: 814 if (refcounted) 815 sock_put(sk); 816 goto discard_it; 817 } 818 819 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 820 int addr_len) 821 { 822 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 823 struct inet_connection_sock *icsk = inet_csk(sk); 824 struct inet_sock *inet = inet_sk(sk); 825 struct ipv6_pinfo *np = inet6_sk(sk); 826 struct dccp_sock *dp = dccp_sk(sk); 827 struct in6_addr *saddr = NULL, *final_p, final; 828 struct ipv6_txoptions *opt; 829 struct flowi6 fl6; 830 struct dst_entry *dst; 831 int addr_type; 832 int err; 833 834 dp->dccps_role = DCCP_ROLE_CLIENT; 835 836 if (addr_len < SIN6_LEN_RFC2133) 837 return -EINVAL; 838 839 if (usin->sin6_family != AF_INET6) 840 return -EAFNOSUPPORT; 841 842 memset(&fl6, 0, sizeof(fl6)); 843 844 if (inet6_test_bit(SNDFLOW, sk)) { 845 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 846 IP6_ECN_flow_init(fl6.flowlabel); 847 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 848 struct ip6_flowlabel *flowlabel; 849 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 850 if (IS_ERR(flowlabel)) 851 return -EINVAL; 852 fl6_sock_release(flowlabel); 853 } 854 } 855 /* 856 * connect() to INADDR_ANY means loopback (BSD'ism). 857 */ 858 if (ipv6_addr_any(&usin->sin6_addr)) 859 usin->sin6_addr.s6_addr[15] = 1; 860 861 addr_type = ipv6_addr_type(&usin->sin6_addr); 862 863 if (addr_type & IPV6_ADDR_MULTICAST) 864 return -ENETUNREACH; 865 866 if (addr_type & IPV6_ADDR_LINKLOCAL) { 867 if (addr_len >= sizeof(struct sockaddr_in6) && 868 usin->sin6_scope_id) { 869 /* If interface is set while binding, indices 870 * must coincide. 871 */ 872 if (sk->sk_bound_dev_if && 873 sk->sk_bound_dev_if != usin->sin6_scope_id) 874 return -EINVAL; 875 876 sk->sk_bound_dev_if = usin->sin6_scope_id; 877 } 878 879 /* Connect to link-local address requires an interface */ 880 if (!sk->sk_bound_dev_if) 881 return -EINVAL; 882 } 883 884 sk->sk_v6_daddr = usin->sin6_addr; 885 np->flow_label = fl6.flowlabel; 886 887 /* 888 * DCCP over IPv4 889 */ 890 if (addr_type == IPV6_ADDR_MAPPED) { 891 u32 exthdrlen = icsk->icsk_ext_hdr_len; 892 struct sockaddr_in sin; 893 894 net_dbg_ratelimited("connect: ipv4 mapped\n"); 895 896 if (ipv6_only_sock(sk)) 897 return -ENETUNREACH; 898 899 sin.sin_family = AF_INET; 900 sin.sin_port = usin->sin6_port; 901 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 902 903 icsk->icsk_af_ops = &dccp_ipv6_mapped; 904 sk->sk_backlog_rcv = dccp_v4_do_rcv; 905 906 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 907 if (err) { 908 icsk->icsk_ext_hdr_len = exthdrlen; 909 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 910 sk->sk_backlog_rcv = dccp_v6_do_rcv; 911 goto failure; 912 } 913 np->saddr = sk->sk_v6_rcv_saddr; 914 return err; 915 } 916 917 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 918 saddr = &sk->sk_v6_rcv_saddr; 919 920 fl6.flowi6_proto = IPPROTO_DCCP; 921 fl6.daddr = sk->sk_v6_daddr; 922 fl6.saddr = saddr ? *saddr : np->saddr; 923 fl6.flowi6_oif = sk->sk_bound_dev_if; 924 fl6.fl6_dport = usin->sin6_port; 925 fl6.fl6_sport = inet->inet_sport; 926 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 927 928 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 929 final_p = fl6_update_dst(&fl6, opt, &final); 930 931 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 932 if (IS_ERR(dst)) { 933 err = PTR_ERR(dst); 934 goto failure; 935 } 936 937 if (saddr == NULL) { 938 saddr = &fl6.saddr; 939 940 err = inet_bhash2_update_saddr(sk, saddr, AF_INET6); 941 if (err) 942 goto failure; 943 } 944 945 /* set the source address */ 946 np->saddr = *saddr; 947 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 948 949 ip6_dst_store(sk, dst, NULL, NULL); 950 951 icsk->icsk_ext_hdr_len = 0; 952 if (opt) 953 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; 954 955 inet->inet_dport = usin->sin6_port; 956 957 dccp_set_state(sk, DCCP_REQUESTING); 958 err = inet6_hash_connect(&dccp_death_row, sk); 959 if (err) 960 goto late_failure; 961 962 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 963 sk->sk_v6_daddr.s6_addr32, 964 inet->inet_sport, 965 inet->inet_dport); 966 err = dccp_connect(sk); 967 if (err) 968 goto late_failure; 969 970 return 0; 971 972 late_failure: 973 dccp_set_state(sk, DCCP_CLOSED); 974 inet_bhash2_reset_saddr(sk); 975 __sk_dst_reset(sk); 976 failure: 977 inet->inet_dport = 0; 978 sk->sk_route_caps = 0; 979 return err; 980 } 981 982 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 983 .queue_xmit = inet6_csk_xmit, 984 .send_check = dccp_v6_send_check, 985 .rebuild_header = inet6_sk_rebuild_header, 986 .conn_request = dccp_v6_conn_request, 987 .syn_recv_sock = dccp_v6_request_recv_sock, 988 .net_header_len = sizeof(struct ipv6hdr), 989 .setsockopt = ipv6_setsockopt, 990 .getsockopt = ipv6_getsockopt, 991 .addr2sockaddr = inet6_csk_addr2sockaddr, 992 .sockaddr_len = sizeof(struct sockaddr_in6), 993 }; 994 995 /* 996 * DCCP over IPv4 via INET6 API 997 */ 998 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 999 .queue_xmit = ip_queue_xmit, 1000 .send_check = dccp_v4_send_check, 1001 .rebuild_header = inet_sk_rebuild_header, 1002 .conn_request = dccp_v6_conn_request, 1003 .syn_recv_sock = dccp_v6_request_recv_sock, 1004 .net_header_len = sizeof(struct iphdr), 1005 .setsockopt = ipv6_setsockopt, 1006 .getsockopt = ipv6_getsockopt, 1007 .addr2sockaddr = inet6_csk_addr2sockaddr, 1008 .sockaddr_len = sizeof(struct sockaddr_in6), 1009 }; 1010 1011 static void dccp_v6_sk_destruct(struct sock *sk) 1012 { 1013 dccp_destruct_common(sk); 1014 inet6_sock_destruct(sk); 1015 } 1016 1017 /* NOTE: A lot of things set to zero explicitly by call to 1018 * sk_alloc() so need not be done here. 1019 */ 1020 static int dccp_v6_init_sock(struct sock *sk) 1021 { 1022 static __u8 dccp_v6_ctl_sock_initialized; 1023 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 1024 1025 if (err == 0) { 1026 if (unlikely(!dccp_v6_ctl_sock_initialized)) 1027 dccp_v6_ctl_sock_initialized = 1; 1028 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 1029 sk->sk_destruct = dccp_v6_sk_destruct; 1030 } 1031 1032 return err; 1033 } 1034 1035 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 1036 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 1037 }; 1038 1039 static struct proto dccp_v6_prot = { 1040 .name = "DCCPv6", 1041 .owner = THIS_MODULE, 1042 .close = dccp_close, 1043 .connect = dccp_v6_connect, 1044 .disconnect = dccp_disconnect, 1045 .ioctl = dccp_ioctl, 1046 .init = dccp_v6_init_sock, 1047 .setsockopt = dccp_setsockopt, 1048 .getsockopt = dccp_getsockopt, 1049 .sendmsg = dccp_sendmsg, 1050 .recvmsg = dccp_recvmsg, 1051 .backlog_rcv = dccp_v6_do_rcv, 1052 .hash = inet6_hash, 1053 .unhash = inet_unhash, 1054 .accept = inet_csk_accept, 1055 .get_port = inet_csk_get_port, 1056 .shutdown = dccp_shutdown, 1057 .destroy = dccp_destroy_sock, 1058 .orphan_count = &dccp_orphan_count, 1059 .max_header = MAX_DCCP_HEADER, 1060 .obj_size = sizeof(struct dccp6_sock), 1061 .ipv6_pinfo_offset = offsetof(struct dccp6_sock, inet6), 1062 .slab_flags = SLAB_TYPESAFE_BY_RCU, 1063 .rsk_prot = &dccp6_request_sock_ops, 1064 .twsk_prot = &dccp6_timewait_sock_ops, 1065 .h.hashinfo = &dccp_hashinfo, 1066 }; 1067 1068 static const struct inet6_protocol dccp_v6_protocol = { 1069 .handler = dccp_v6_rcv, 1070 .err_handler = dccp_v6_err, 1071 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1072 }; 1073 1074 static const struct proto_ops inet6_dccp_ops = { 1075 .family = PF_INET6, 1076 .owner = THIS_MODULE, 1077 .release = inet6_release, 1078 .bind = inet6_bind, 1079 .connect = inet_stream_connect, 1080 .socketpair = sock_no_socketpair, 1081 .accept = inet_accept, 1082 .getname = inet6_getname, 1083 .poll = dccp_poll, 1084 .ioctl = inet6_ioctl, 1085 .gettstamp = sock_gettstamp, 1086 .listen = inet_dccp_listen, 1087 .shutdown = inet_shutdown, 1088 .setsockopt = sock_common_setsockopt, 1089 .getsockopt = sock_common_getsockopt, 1090 .sendmsg = inet_sendmsg, 1091 .recvmsg = sock_common_recvmsg, 1092 .mmap = sock_no_mmap, 1093 #ifdef CONFIG_COMPAT 1094 .compat_ioctl = inet6_compat_ioctl, 1095 #endif 1096 }; 1097 1098 static struct inet_protosw dccp_v6_protosw = { 1099 .type = SOCK_DCCP, 1100 .protocol = IPPROTO_DCCP, 1101 .prot = &dccp_v6_prot, 1102 .ops = &inet6_dccp_ops, 1103 .flags = INET_PROTOSW_ICSK, 1104 }; 1105 1106 static int __net_init dccp_v6_init_net(struct net *net) 1107 { 1108 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id); 1109 1110 if (dccp_hashinfo.bhash == NULL) 1111 return -ESOCKTNOSUPPORT; 1112 1113 return inet_ctl_sock_create(&pn->v6_ctl_sk, PF_INET6, 1114 SOCK_DCCP, IPPROTO_DCCP, net); 1115 } 1116 1117 static void __net_exit dccp_v6_exit_net(struct net *net) 1118 { 1119 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id); 1120 1121 inet_ctl_sock_destroy(pn->v6_ctl_sk); 1122 } 1123 1124 static struct pernet_operations dccp_v6_ops = { 1125 .init = dccp_v6_init_net, 1126 .exit = dccp_v6_exit_net, 1127 .id = &dccp_v6_pernet_id, 1128 .size = sizeof(struct dccp_v6_pernet), 1129 }; 1130 1131 static int __init dccp_v6_init(void) 1132 { 1133 int err = proto_register(&dccp_v6_prot, 1); 1134 1135 if (err) 1136 goto out; 1137 1138 inet6_register_protosw(&dccp_v6_protosw); 1139 1140 err = register_pernet_subsys(&dccp_v6_ops); 1141 if (err) 1142 goto out_destroy_ctl_sock; 1143 1144 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1145 if (err) 1146 goto out_unregister_proto; 1147 1148 out: 1149 return err; 1150 out_unregister_proto: 1151 unregister_pernet_subsys(&dccp_v6_ops); 1152 out_destroy_ctl_sock: 1153 inet6_unregister_protosw(&dccp_v6_protosw); 1154 proto_unregister(&dccp_v6_prot); 1155 goto out; 1156 } 1157 1158 static void __exit dccp_v6_exit(void) 1159 { 1160 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1161 unregister_pernet_subsys(&dccp_v6_ops); 1162 inet6_unregister_protosw(&dccp_v6_protosw); 1163 proto_unregister(&dccp_v6_prot); 1164 } 1165 1166 module_init(dccp_v6_init); 1167 module_exit(dccp_v6_exit); 1168 1169 /* 1170 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) 1171 * values directly, Also cover the case where the protocol is not specified, 1172 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP 1173 */ 1174 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6); 1175 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6); 1176 MODULE_LICENSE("GPL"); 1177 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>"); 1178 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol"); 1179