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 = (const struct ipv6hdr *)skb->data; 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 /* Only need dccph_dport & dccph_sport which are the first 87 * 4 bytes in dccp header. 88 * Our caller (icmpv6_notify()) already pulled 8 bytes for us. 89 */ 90 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8); 91 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8); 92 dh = (struct dccp_hdr *)(skb->data + offset); 93 94 sk = __inet6_lookup_established(net, &dccp_hashinfo, 95 &hdr->daddr, dh->dccph_dport, 96 &hdr->saddr, ntohs(dh->dccph_sport), 97 inet6_iif(skb), 0); 98 99 if (!sk) { 100 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), 101 ICMP6_MIB_INERRORS); 102 return -ENOENT; 103 } 104 105 if (sk->sk_state == DCCP_TIME_WAIT) { 106 inet_twsk_put(inet_twsk(sk)); 107 return 0; 108 } 109 seq = dccp_hdr_seq(dh); 110 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 111 dccp_req_err(sk, seq); 112 return 0; 113 } 114 115 bh_lock_sock(sk); 116 if (sock_owned_by_user(sk)) 117 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 118 119 if (sk->sk_state == DCCP_CLOSED) 120 goto out; 121 122 dp = dccp_sk(sk); 123 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) && 124 !between48(seq, dp->dccps_awl, dp->dccps_awh)) { 125 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 126 goto out; 127 } 128 129 np = inet6_sk(sk); 130 131 if (type == NDISC_REDIRECT) { 132 if (!sock_owned_by_user(sk)) { 133 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie); 134 135 if (dst) 136 dst->ops->redirect(dst, sk, skb); 137 } 138 goto out; 139 } 140 141 if (type == ICMPV6_PKT_TOOBIG) { 142 struct dst_entry *dst = NULL; 143 144 if (!ip6_sk_accept_pmtu(sk)) 145 goto out; 146 147 if (sock_owned_by_user(sk)) 148 goto out; 149 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED)) 150 goto out; 151 152 dst = inet6_csk_update_pmtu(sk, ntohl(info)); 153 if (!dst) 154 goto out; 155 156 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) 157 dccp_sync_mss(sk, dst_mtu(dst)); 158 goto out; 159 } 160 161 icmpv6_err_convert(type, code, &err); 162 163 /* Might be for an request_sock */ 164 switch (sk->sk_state) { 165 case DCCP_REQUESTING: 166 case DCCP_RESPOND: /* Cannot happen. 167 It can, it SYNs are crossed. --ANK */ 168 if (!sock_owned_by_user(sk)) { 169 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 170 sk->sk_err = err; 171 /* 172 * Wake people up to see the error 173 * (see connect in sock.c) 174 */ 175 sk_error_report(sk); 176 dccp_done(sk); 177 } else 178 sk->sk_err_soft = err; 179 goto out; 180 } 181 182 if (!sock_owned_by_user(sk) && np->recverr) { 183 sk->sk_err = err; 184 sk_error_report(sk); 185 } else 186 sk->sk_err_soft = err; 187 188 out: 189 bh_unlock_sock(sk); 190 sock_put(sk); 191 return 0; 192 } 193 194 195 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req) 196 { 197 struct inet_request_sock *ireq = inet_rsk(req); 198 struct ipv6_pinfo *np = inet6_sk(sk); 199 struct sk_buff *skb; 200 struct in6_addr *final_p, final; 201 struct flowi6 fl6; 202 int err = -1; 203 struct dst_entry *dst; 204 205 memset(&fl6, 0, sizeof(fl6)); 206 fl6.flowi6_proto = IPPROTO_DCCP; 207 fl6.daddr = ireq->ir_v6_rmt_addr; 208 fl6.saddr = ireq->ir_v6_loc_addr; 209 fl6.flowlabel = 0; 210 fl6.flowi6_oif = ireq->ir_iif; 211 fl6.fl6_dport = ireq->ir_rmt_port; 212 fl6.fl6_sport = htons(ireq->ir_num); 213 security_req_classify_flow(req, flowi6_to_flowi_common(&fl6)); 214 215 216 rcu_read_lock(); 217 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final); 218 rcu_read_unlock(); 219 220 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 221 if (IS_ERR(dst)) { 222 err = PTR_ERR(dst); 223 dst = NULL; 224 goto done; 225 } 226 227 skb = dccp_make_response(sk, dst, req); 228 if (skb != NULL) { 229 struct dccp_hdr *dh = dccp_hdr(skb); 230 struct ipv6_txoptions *opt; 231 232 dh->dccph_checksum = dccp_v6_csum_finish(skb, 233 &ireq->ir_v6_loc_addr, 234 &ireq->ir_v6_rmt_addr); 235 fl6.daddr = ireq->ir_v6_rmt_addr; 236 rcu_read_lock(); 237 opt = ireq->ipv6_opt; 238 if (!opt) 239 opt = rcu_dereference(np->opt); 240 err = ip6_xmit(sk, skb, &fl6, sk->sk_mark, opt, np->tclass, 241 sk->sk_priority); 242 rcu_read_unlock(); 243 err = net_xmit_eval(err); 244 } 245 246 done: 247 dst_release(dst); 248 return err; 249 } 250 251 static void dccp_v6_reqsk_destructor(struct request_sock *req) 252 { 253 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); 254 kfree(inet_rsk(req)->ipv6_opt); 255 kfree_skb(inet_rsk(req)->pktopts); 256 } 257 258 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) 259 { 260 const struct ipv6hdr *rxip6h; 261 struct sk_buff *skb; 262 struct flowi6 fl6; 263 struct net *net = dev_net(skb_dst(rxskb)->dev); 264 struct dccp_v6_pernet *pn; 265 struct sock *ctl_sk; 266 struct dst_entry *dst; 267 268 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) 269 return; 270 271 if (!ipv6_unicast_destination(rxskb)) 272 return; 273 274 pn = net_generic(net, dccp_v6_pernet_id); 275 ctl_sk = pn->v6_ctl_sk; 276 skb = dccp_ctl_make_reset(ctl_sk, rxskb); 277 if (skb == NULL) 278 return; 279 280 rxip6h = ipv6_hdr(rxskb); 281 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr, 282 &rxip6h->daddr); 283 284 memset(&fl6, 0, sizeof(fl6)); 285 fl6.daddr = rxip6h->saddr; 286 fl6.saddr = rxip6h->daddr; 287 288 fl6.flowi6_proto = IPPROTO_DCCP; 289 fl6.flowi6_oif = inet6_iif(rxskb); 290 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport; 291 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport; 292 security_skb_classify_flow(rxskb, flowi6_to_flowi_common(&fl6)); 293 294 /* sk = NULL, but it is safe for now. RST socket required. */ 295 dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL); 296 if (!IS_ERR(dst)) { 297 skb_dst_set(skb, dst); 298 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0, 0); 299 DCCP_INC_STATS(DCCP_MIB_OUTSEGS); 300 DCCP_INC_STATS(DCCP_MIB_OUTRSTS); 301 return; 302 } 303 304 kfree_skb(skb); 305 } 306 307 static struct request_sock_ops dccp6_request_sock_ops = { 308 .family = AF_INET6, 309 .obj_size = sizeof(struct dccp6_request_sock), 310 .rtx_syn_ack = dccp_v6_send_response, 311 .send_ack = dccp_reqsk_send_ack, 312 .destructor = dccp_v6_reqsk_destructor, 313 .send_reset = dccp_v6_ctl_send_reset, 314 .syn_ack_timeout = dccp_syn_ack_timeout, 315 }; 316 317 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 318 { 319 struct request_sock *req; 320 struct dccp_request_sock *dreq; 321 struct inet_request_sock *ireq; 322 struct ipv6_pinfo *np = inet6_sk(sk); 323 const __be32 service = dccp_hdr_request(skb)->dccph_req_service; 324 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); 325 326 if (skb->protocol == htons(ETH_P_IP)) 327 return dccp_v4_conn_request(sk, skb); 328 329 if (!ipv6_unicast_destination(skb)) 330 return 0; /* discard, don't send a reset here */ 331 332 if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { 333 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); 334 return 0; 335 } 336 337 if (dccp_bad_service_code(sk, service)) { 338 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; 339 goto drop; 340 } 341 /* 342 * There are no SYN attacks on IPv6, yet... 343 */ 344 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 345 if (inet_csk_reqsk_queue_is_full(sk)) 346 goto drop; 347 348 if (sk_acceptq_is_full(sk)) 349 goto drop; 350 351 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true); 352 if (req == NULL) 353 goto drop; 354 355 if (dccp_reqsk_init(req, dccp_sk(sk), skb)) 356 goto drop_and_free; 357 358 dreq = dccp_rsk(req); 359 if (dccp_parse_options(sk, dreq, skb)) 360 goto drop_and_free; 361 362 if (security_inet_conn_request(sk, skb, req)) 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 (ipv6_opt_accepted(sk, skb, IP6CB(skb)) || 372 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || 373 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { 374 refcount_inc(&skb->users); 375 ireq->pktopts = skb; 376 } 377 ireq->ir_iif = READ_ONCE(sk->sk_bound_dev_if); 378 379 /* So that link locals have meaning */ 380 if (!ireq->ir_iif && 381 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 382 ireq->ir_iif = inet6_iif(skb); 383 384 /* 385 * Step 3: Process LISTEN state 386 * 387 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 388 * 389 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 390 */ 391 dreq->dreq_isr = dcb->dccpd_seq; 392 dreq->dreq_gsr = dreq->dreq_isr; 393 dreq->dreq_iss = dccp_v6_init_sequence(skb); 394 dreq->dreq_gss = dreq->dreq_iss; 395 dreq->dreq_service = service; 396 397 if (dccp_v6_send_response(sk, req)) 398 goto drop_and_free; 399 400 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 401 reqsk_put(req); 402 return 0; 403 404 drop_and_free: 405 reqsk_free(req); 406 drop: 407 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 408 return -1; 409 } 410 411 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 412 struct sk_buff *skb, 413 struct request_sock *req, 414 struct dst_entry *dst, 415 struct request_sock *req_unhash, 416 bool *own_req) 417 { 418 struct inet_request_sock *ireq = inet_rsk(req); 419 struct ipv6_pinfo *newnp; 420 const struct ipv6_pinfo *np = inet6_sk(sk); 421 struct ipv6_txoptions *opt; 422 struct inet_sock *newinet; 423 struct dccp6_sock *newdp6; 424 struct sock *newsk; 425 426 if (skb->protocol == htons(ETH_P_IP)) { 427 /* 428 * v6 mapped 429 */ 430 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 431 req_unhash, own_req); 432 if (newsk == NULL) 433 return NULL; 434 435 newdp6 = (struct dccp6_sock *)newsk; 436 newinet = inet_sk(newsk); 437 newinet->pinet6 = &newdp6->inet6; 438 newnp = inet6_sk(newsk); 439 440 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 441 442 newnp->saddr = newsk->sk_v6_rcv_saddr; 443 444 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 445 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 446 newnp->pktoptions = NULL; 447 newnp->opt = NULL; 448 newnp->ipv6_mc_list = NULL; 449 newnp->ipv6_ac_list = NULL; 450 newnp->ipv6_fl_list = NULL; 451 newnp->mcast_oif = inet_iif(skb); 452 newnp->mcast_hops = ip_hdr(skb)->ttl; 453 454 /* 455 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 456 * here, dccp_create_openreq_child now does this for us, see the comment in 457 * that function for the gory details. -acme 458 */ 459 460 /* It is tricky place. Until this moment IPv4 tcp 461 worked with IPv6 icsk.icsk_af_ops. 462 Sync it now. 463 */ 464 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 465 466 return newsk; 467 } 468 469 470 if (sk_acceptq_is_full(sk)) 471 goto out_overflow; 472 473 if (!dst) { 474 struct flowi6 fl6; 475 476 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 477 if (!dst) 478 goto out; 479 } 480 481 newsk = dccp_create_openreq_child(sk, req, skb); 482 if (newsk == NULL) 483 goto out_nonewsk; 484 485 /* 486 * No need to charge this sock to the relevant IPv6 refcnt debug socks 487 * count here, dccp_create_openreq_child now does this for us, see the 488 * comment in that function for the gory details. -acme 489 */ 490 491 ip6_dst_store(newsk, dst, NULL, NULL); 492 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 493 NETIF_F_TSO); 494 newdp6 = (struct dccp6_sock *)newsk; 495 newinet = inet_sk(newsk); 496 newinet->pinet6 = &newdp6->inet6; 497 newnp = inet6_sk(newsk); 498 499 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 500 501 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 502 newnp->saddr = ireq->ir_v6_loc_addr; 503 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 504 newsk->sk_bound_dev_if = ireq->ir_iif; 505 506 /* Now IPv6 options... 507 508 First: no IPv4 options. 509 */ 510 newinet->inet_opt = NULL; 511 512 /* Clone RX bits */ 513 newnp->rxopt.all = np->rxopt.all; 514 515 newnp->ipv6_mc_list = NULL; 516 newnp->ipv6_ac_list = NULL; 517 newnp->ipv6_fl_list = NULL; 518 newnp->pktoptions = NULL; 519 newnp->opt = NULL; 520 newnp->mcast_oif = inet6_iif(skb); 521 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 522 523 /* 524 * Clone native IPv6 options from listening socket (if any) 525 * 526 * Yes, keeping reference count would be much more clever, but we make 527 * one more one thing there: reattach optmem to newsk. 528 */ 529 opt = ireq->ipv6_opt; 530 if (!opt) 531 opt = rcu_dereference(np->opt); 532 if (opt) { 533 opt = ipv6_dup_options(newsk, opt); 534 RCU_INIT_POINTER(newnp->opt, opt); 535 } 536 inet_csk(newsk)->icsk_ext_hdr_len = 0; 537 if (opt) 538 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 539 opt->opt_flen; 540 541 dccp_sync_mss(newsk, dst_mtu(dst)); 542 543 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 544 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 545 546 if (__inet_inherit_port(sk, newsk) < 0) { 547 inet_csk_prepare_forced_close(newsk); 548 dccp_done(newsk); 549 goto out; 550 } 551 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL); 552 /* Clone pktoptions received with SYN, if we own the req */ 553 if (*own_req && ireq->pktopts) { 554 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC); 555 consume_skb(ireq->pktopts); 556 ireq->pktopts = NULL; 557 if (newnp->pktoptions) 558 skb_set_owner_r(newnp->pktoptions, newsk); 559 } 560 561 return newsk; 562 563 out_overflow: 564 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 565 out_nonewsk: 566 dst_release(dst); 567 out: 568 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 569 return NULL; 570 } 571 572 /* The socket must have it's spinlock held when we get 573 * here. 574 * 575 * We have a potential double-lock case here, so even when 576 * doing backlog processing we use the BH locking scheme. 577 * This is because we cannot sleep with the original spinlock 578 * held. 579 */ 580 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 581 { 582 struct ipv6_pinfo *np = inet6_sk(sk); 583 struct sk_buff *opt_skb = NULL; 584 585 /* Imagine: socket is IPv6. IPv4 packet arrives, 586 goes to IPv4 receive handler and backlogged. 587 From backlog it always goes here. Kerboom... 588 Fortunately, dccp_rcv_established and rcv_established 589 handle them correctly, but it is not case with 590 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 591 */ 592 593 if (skb->protocol == htons(ETH_P_IP)) 594 return dccp_v4_do_rcv(sk, skb); 595 596 if (sk_filter(sk, skb)) 597 goto discard; 598 599 /* 600 * socket locking is here for SMP purposes as backlog rcv is currently 601 * called with bh processing disabled. 602 */ 603 604 /* Do Stevens' IPV6_PKTOPTIONS. 605 606 Yes, guys, it is the only place in our code, where we 607 may make it not affecting IPv4. 608 The rest of code is protocol independent, 609 and I do not like idea to uglify IPv4. 610 611 Actually, all the idea behind IPV6_PKTOPTIONS 612 looks not very well thought. For now we latch 613 options, received in the last packet, enqueued 614 by tcp. Feel free to propose better solution. 615 --ANK (980728) 616 */ 617 if (np->rxopt.all) 618 opt_skb = skb_clone(skb, GFP_ATOMIC); 619 620 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 621 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 622 goto reset; 623 if (opt_skb) 624 goto ipv6_pktoptions; 625 return 0; 626 } 627 628 /* 629 * Step 3: Process LISTEN state 630 * If S.state == LISTEN, 631 * If P.type == Request or P contains a valid Init Cookie option, 632 * (* Must scan the packet's options to check for Init 633 * Cookies. Only Init Cookies are processed here, 634 * however; other options are processed in Step 8. This 635 * scan need only be performed if the endpoint uses Init 636 * Cookies *) 637 * (* Generate a new socket and switch to that socket *) 638 * Set S := new socket for this port pair 639 * S.state = RESPOND 640 * Choose S.ISS (initial seqno) or set from Init Cookies 641 * Initialize S.GAR := S.ISS 642 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 643 * Continue with S.state == RESPOND 644 * (* A Response packet will be generated in Step 11 *) 645 * Otherwise, 646 * Generate Reset(No Connection) unless P.type == Reset 647 * Drop packet and return 648 * 649 * NOTE: the check for the packet types is done in 650 * dccp_rcv_state_process 651 */ 652 653 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 654 goto reset; 655 if (opt_skb) 656 goto ipv6_pktoptions; 657 return 0; 658 659 reset: 660 dccp_v6_ctl_send_reset(sk, skb); 661 discard: 662 if (opt_skb != NULL) 663 __kfree_skb(opt_skb); 664 kfree_skb(skb); 665 return 0; 666 667 /* Handling IPV6_PKTOPTIONS skb the similar 668 * way it's done for net/ipv6/tcp_ipv6.c 669 */ 670 ipv6_pktoptions: 671 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) { 672 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) 673 np->mcast_oif = inet6_iif(opt_skb); 674 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) 675 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit; 676 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) 677 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); 678 if (np->repflow) 679 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb)); 680 if (ipv6_opt_accepted(sk, opt_skb, 681 &DCCP_SKB_CB(opt_skb)->header.h6)) { 682 skb_set_owner_r(opt_skb, sk); 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); 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; 789 790 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, 791 refcounted) ? -1 : 0; 792 793 no_dccp_socket: 794 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 795 goto discard_it; 796 /* 797 * Step 2: 798 * If no socket ... 799 * Generate Reset(No Connection) unless P.type == Reset 800 * Drop packet and return 801 */ 802 if (dh->dccph_type != DCCP_PKT_RESET) { 803 DCCP_SKB_CB(skb)->dccpd_reset_code = 804 DCCP_RESET_CODE_NO_CONNECTION; 805 dccp_v6_ctl_send_reset(sk, skb); 806 } 807 808 discard_it: 809 kfree_skb(skb); 810 return 0; 811 812 discard_and_relse: 813 if (refcounted) 814 sock_put(sk); 815 goto discard_it; 816 } 817 818 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 819 int addr_len) 820 { 821 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 822 struct inet_connection_sock *icsk = inet_csk(sk); 823 struct inet_sock *inet = inet_sk(sk); 824 struct ipv6_pinfo *np = inet6_sk(sk); 825 struct dccp_sock *dp = dccp_sk(sk); 826 struct in6_addr *saddr = NULL, *final_p, final; 827 struct ipv6_txoptions *opt; 828 struct flowi6 fl6; 829 struct dst_entry *dst; 830 int addr_type; 831 int err; 832 833 dp->dccps_role = DCCP_ROLE_CLIENT; 834 835 if (addr_len < SIN6_LEN_RFC2133) 836 return -EINVAL; 837 838 if (usin->sin6_family != AF_INET6) 839 return -EAFNOSUPPORT; 840 841 memset(&fl6, 0, sizeof(fl6)); 842 843 if (np->sndflow) { 844 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 845 IP6_ECN_flow_init(fl6.flowlabel); 846 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 847 struct ip6_flowlabel *flowlabel; 848 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 849 if (IS_ERR(flowlabel)) 850 return -EINVAL; 851 fl6_sock_release(flowlabel); 852 } 853 } 854 /* 855 * connect() to INADDR_ANY means loopback (BSD'ism). 856 */ 857 if (ipv6_addr_any(&usin->sin6_addr)) 858 usin->sin6_addr.s6_addr[15] = 1; 859 860 addr_type = ipv6_addr_type(&usin->sin6_addr); 861 862 if (addr_type & IPV6_ADDR_MULTICAST) 863 return -ENETUNREACH; 864 865 if (addr_type & IPV6_ADDR_LINKLOCAL) { 866 if (addr_len >= sizeof(struct sockaddr_in6) && 867 usin->sin6_scope_id) { 868 /* If interface is set while binding, indices 869 * must coincide. 870 */ 871 if (sk->sk_bound_dev_if && 872 sk->sk_bound_dev_if != usin->sin6_scope_id) 873 return -EINVAL; 874 875 sk->sk_bound_dev_if = usin->sin6_scope_id; 876 } 877 878 /* Connect to link-local address requires an interface */ 879 if (!sk->sk_bound_dev_if) 880 return -EINVAL; 881 } 882 883 sk->sk_v6_daddr = usin->sin6_addr; 884 np->flow_label = fl6.flowlabel; 885 886 /* 887 * DCCP over IPv4 888 */ 889 if (addr_type == IPV6_ADDR_MAPPED) { 890 u32 exthdrlen = icsk->icsk_ext_hdr_len; 891 struct sockaddr_in sin; 892 893 SOCK_DEBUG(sk, "connect: ipv4 mapped\n"); 894 895 if (ipv6_only_sock(sk)) 896 return -ENETUNREACH; 897 898 sin.sin_family = AF_INET; 899 sin.sin_port = usin->sin6_port; 900 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 901 902 icsk->icsk_af_ops = &dccp_ipv6_mapped; 903 sk->sk_backlog_rcv = dccp_v4_do_rcv; 904 905 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 906 if (err) { 907 icsk->icsk_ext_hdr_len = exthdrlen; 908 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 909 sk->sk_backlog_rcv = dccp_v6_do_rcv; 910 goto failure; 911 } 912 np->saddr = sk->sk_v6_rcv_saddr; 913 return err; 914 } 915 916 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 917 saddr = &sk->sk_v6_rcv_saddr; 918 919 fl6.flowi6_proto = IPPROTO_DCCP; 920 fl6.daddr = sk->sk_v6_daddr; 921 fl6.saddr = saddr ? *saddr : np->saddr; 922 fl6.flowi6_oif = sk->sk_bound_dev_if; 923 fl6.fl6_dport = usin->sin6_port; 924 fl6.fl6_sport = inet->inet_sport; 925 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 926 927 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 928 final_p = fl6_update_dst(&fl6, opt, &final); 929 930 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 931 if (IS_ERR(dst)) { 932 err = PTR_ERR(dst); 933 goto failure; 934 } 935 936 if (saddr == NULL) { 937 saddr = &fl6.saddr; 938 sk->sk_v6_rcv_saddr = *saddr; 939 } 940 941 /* set the source address */ 942 np->saddr = *saddr; 943 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 944 945 ip6_dst_store(sk, dst, NULL, NULL); 946 947 icsk->icsk_ext_hdr_len = 0; 948 if (opt) 949 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; 950 951 inet->inet_dport = usin->sin6_port; 952 953 dccp_set_state(sk, DCCP_REQUESTING); 954 err = inet6_hash_connect(&dccp_death_row, sk); 955 if (err) 956 goto late_failure; 957 958 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 959 sk->sk_v6_daddr.s6_addr32, 960 inet->inet_sport, 961 inet->inet_dport); 962 err = dccp_connect(sk); 963 if (err) 964 goto late_failure; 965 966 return 0; 967 968 late_failure: 969 dccp_set_state(sk, DCCP_CLOSED); 970 __sk_dst_reset(sk); 971 failure: 972 inet->inet_dport = 0; 973 sk->sk_route_caps = 0; 974 return err; 975 } 976 977 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 978 .queue_xmit = inet6_csk_xmit, 979 .send_check = dccp_v6_send_check, 980 .rebuild_header = inet6_sk_rebuild_header, 981 .conn_request = dccp_v6_conn_request, 982 .syn_recv_sock = dccp_v6_request_recv_sock, 983 .net_header_len = sizeof(struct ipv6hdr), 984 .setsockopt = ipv6_setsockopt, 985 .getsockopt = ipv6_getsockopt, 986 .addr2sockaddr = inet6_csk_addr2sockaddr, 987 .sockaddr_len = sizeof(struct sockaddr_in6), 988 }; 989 990 /* 991 * DCCP over IPv4 via INET6 API 992 */ 993 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 994 .queue_xmit = ip_queue_xmit, 995 .send_check = dccp_v4_send_check, 996 .rebuild_header = inet_sk_rebuild_header, 997 .conn_request = dccp_v6_conn_request, 998 .syn_recv_sock = dccp_v6_request_recv_sock, 999 .net_header_len = sizeof(struct iphdr), 1000 .setsockopt = ipv6_setsockopt, 1001 .getsockopt = ipv6_getsockopt, 1002 .addr2sockaddr = inet6_csk_addr2sockaddr, 1003 .sockaddr_len = sizeof(struct sockaddr_in6), 1004 }; 1005 1006 /* NOTE: A lot of things set to zero explicitly by call to 1007 * sk_alloc() so need not be done here. 1008 */ 1009 static int dccp_v6_init_sock(struct sock *sk) 1010 { 1011 static __u8 dccp_v6_ctl_sock_initialized; 1012 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 1013 1014 if (err == 0) { 1015 if (unlikely(!dccp_v6_ctl_sock_initialized)) 1016 dccp_v6_ctl_sock_initialized = 1; 1017 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 1018 } 1019 1020 return err; 1021 } 1022 1023 static void dccp_v6_destroy_sock(struct sock *sk) 1024 { 1025 dccp_destroy_sock(sk); 1026 inet6_destroy_sock(sk); 1027 } 1028 1029 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 1030 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 1031 }; 1032 1033 static struct proto dccp_v6_prot = { 1034 .name = "DCCPv6", 1035 .owner = THIS_MODULE, 1036 .close = dccp_close, 1037 .connect = dccp_v6_connect, 1038 .disconnect = dccp_disconnect, 1039 .ioctl = dccp_ioctl, 1040 .init = dccp_v6_init_sock, 1041 .setsockopt = dccp_setsockopt, 1042 .getsockopt = dccp_getsockopt, 1043 .sendmsg = dccp_sendmsg, 1044 .recvmsg = dccp_recvmsg, 1045 .backlog_rcv = dccp_v6_do_rcv, 1046 .hash = inet6_hash, 1047 .unhash = inet_unhash, 1048 .accept = inet_csk_accept, 1049 .get_port = inet_csk_get_port, 1050 .shutdown = dccp_shutdown, 1051 .destroy = dccp_v6_destroy_sock, 1052 .orphan_count = &dccp_orphan_count, 1053 .max_header = MAX_DCCP_HEADER, 1054 .obj_size = sizeof(struct dccp6_sock), 1055 .slab_flags = SLAB_TYPESAFE_BY_RCU, 1056 .rsk_prot = &dccp6_request_sock_ops, 1057 .twsk_prot = &dccp6_timewait_sock_ops, 1058 .h.hashinfo = &dccp_hashinfo, 1059 }; 1060 1061 static const struct inet6_protocol dccp_v6_protocol = { 1062 .handler = dccp_v6_rcv, 1063 .err_handler = dccp_v6_err, 1064 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1065 }; 1066 1067 static const struct proto_ops inet6_dccp_ops = { 1068 .family = PF_INET6, 1069 .owner = THIS_MODULE, 1070 .release = inet6_release, 1071 .bind = inet6_bind, 1072 .connect = inet_stream_connect, 1073 .socketpair = sock_no_socketpair, 1074 .accept = inet_accept, 1075 .getname = inet6_getname, 1076 .poll = dccp_poll, 1077 .ioctl = inet6_ioctl, 1078 .gettstamp = sock_gettstamp, 1079 .listen = inet_dccp_listen, 1080 .shutdown = inet_shutdown, 1081 .setsockopt = sock_common_setsockopt, 1082 .getsockopt = sock_common_getsockopt, 1083 .sendmsg = inet_sendmsg, 1084 .recvmsg = sock_common_recvmsg, 1085 .mmap = sock_no_mmap, 1086 .sendpage = sock_no_sendpage, 1087 #ifdef CONFIG_COMPAT 1088 .compat_ioctl = inet6_compat_ioctl, 1089 #endif 1090 }; 1091 1092 static struct inet_protosw dccp_v6_protosw = { 1093 .type = SOCK_DCCP, 1094 .protocol = IPPROTO_DCCP, 1095 .prot = &dccp_v6_prot, 1096 .ops = &inet6_dccp_ops, 1097 .flags = INET_PROTOSW_ICSK, 1098 }; 1099 1100 static int __net_init dccp_v6_init_net(struct net *net) 1101 { 1102 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id); 1103 1104 if (dccp_hashinfo.bhash == NULL) 1105 return -ESOCKTNOSUPPORT; 1106 1107 return inet_ctl_sock_create(&pn->v6_ctl_sk, PF_INET6, 1108 SOCK_DCCP, IPPROTO_DCCP, net); 1109 } 1110 1111 static void __net_exit dccp_v6_exit_net(struct net *net) 1112 { 1113 struct dccp_v6_pernet *pn = net_generic(net, dccp_v6_pernet_id); 1114 1115 inet_ctl_sock_destroy(pn->v6_ctl_sk); 1116 } 1117 1118 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list) 1119 { 1120 inet_twsk_purge(&dccp_hashinfo, AF_INET6); 1121 } 1122 1123 static struct pernet_operations dccp_v6_ops = { 1124 .init = dccp_v6_init_net, 1125 .exit = dccp_v6_exit_net, 1126 .exit_batch = dccp_v6_exit_batch, 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