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/sock.h> 31 32 #include "dccp.h" 33 #include "ipv6.h" 34 #include "feat.h" 35 36 /* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */ 37 38 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped; 39 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops; 40 41 /* add pseudo-header to DCCP checksum stored in skb->csum */ 42 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb, 43 const struct in6_addr *saddr, 44 const struct in6_addr *daddr) 45 { 46 return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum); 47 } 48 49 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb) 50 { 51 struct ipv6_pinfo *np = inet6_sk(sk); 52 struct dccp_hdr *dh = dccp_hdr(skb); 53 54 dccp_csum_outgoing(skb); 55 dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr); 56 } 57 58 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb) 59 { 60 return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32, 61 ipv6_hdr(skb)->saddr.s6_addr32, 62 dccp_hdr(skb)->dccph_dport, 63 dccp_hdr(skb)->dccph_sport ); 64 65 } 66 67 static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 68 u8 type, u8 code, int offset, __be32 info) 69 { 70 const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data; 71 const struct dccp_hdr *dh; 72 struct dccp_sock *dp; 73 struct ipv6_pinfo *np; 74 struct sock *sk; 75 int err; 76 __u64 seq; 77 struct net *net = dev_net(skb->dev); 78 79 /* Only need dccph_dport & dccph_sport which are the first 80 * 4 bytes in dccp header. 81 * Our caller (icmpv6_notify()) already pulled 8 bytes for us. 82 */ 83 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8); 84 BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8); 85 dh = (struct dccp_hdr *)(skb->data + offset); 86 87 sk = __inet6_lookup_established(net, &dccp_hashinfo, 88 &hdr->daddr, dh->dccph_dport, 89 &hdr->saddr, ntohs(dh->dccph_sport), 90 inet6_iif(skb), 0); 91 92 if (!sk) { 93 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), 94 ICMP6_MIB_INERRORS); 95 return -ENOENT; 96 } 97 98 if (sk->sk_state == DCCP_TIME_WAIT) { 99 inet_twsk_put(inet_twsk(sk)); 100 return 0; 101 } 102 seq = dccp_hdr_seq(dh); 103 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 104 dccp_req_err(sk, seq); 105 return 0; 106 } 107 108 bh_lock_sock(sk); 109 if (sock_owned_by_user(sk)) 110 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 111 112 if (sk->sk_state == DCCP_CLOSED) 113 goto out; 114 115 dp = dccp_sk(sk); 116 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) && 117 !between48(seq, dp->dccps_awl, dp->dccps_awh)) { 118 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 119 goto out; 120 } 121 122 np = inet6_sk(sk); 123 124 if (type == NDISC_REDIRECT) { 125 if (!sock_owned_by_user(sk)) { 126 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie); 127 128 if (dst) 129 dst->ops->redirect(dst, sk, skb); 130 } 131 goto out; 132 } 133 134 if (type == ICMPV6_PKT_TOOBIG) { 135 struct dst_entry *dst = NULL; 136 137 if (!ip6_sk_accept_pmtu(sk)) 138 goto out; 139 140 if (sock_owned_by_user(sk)) 141 goto out; 142 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED)) 143 goto out; 144 145 dst = inet6_csk_update_pmtu(sk, ntohl(info)); 146 if (!dst) 147 goto out; 148 149 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) 150 dccp_sync_mss(sk, dst_mtu(dst)); 151 goto out; 152 } 153 154 icmpv6_err_convert(type, code, &err); 155 156 /* Might be for an request_sock */ 157 switch (sk->sk_state) { 158 case DCCP_REQUESTING: 159 case DCCP_RESPOND: /* Cannot happen. 160 It can, it SYNs are crossed. --ANK */ 161 if (!sock_owned_by_user(sk)) { 162 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 163 sk->sk_err = err; 164 /* 165 * Wake people up to see the error 166 * (see connect in sock.c) 167 */ 168 sk->sk_error_report(sk); 169 dccp_done(sk); 170 } else 171 sk->sk_err_soft = err; 172 goto out; 173 } 174 175 if (!sock_owned_by_user(sk) && np->recverr) { 176 sk->sk_err = err; 177 sk->sk_error_report(sk); 178 } else 179 sk->sk_err_soft = err; 180 181 out: 182 bh_unlock_sock(sk); 183 sock_put(sk); 184 return 0; 185 } 186 187 188 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req) 189 { 190 struct inet_request_sock *ireq = inet_rsk(req); 191 struct ipv6_pinfo *np = inet6_sk(sk); 192 struct sk_buff *skb; 193 struct in6_addr *final_p, final; 194 struct flowi6 fl6; 195 int err = -1; 196 struct dst_entry *dst; 197 198 memset(&fl6, 0, sizeof(fl6)); 199 fl6.flowi6_proto = IPPROTO_DCCP; 200 fl6.daddr = ireq->ir_v6_rmt_addr; 201 fl6.saddr = ireq->ir_v6_loc_addr; 202 fl6.flowlabel = 0; 203 fl6.flowi6_oif = ireq->ir_iif; 204 fl6.fl6_dport = ireq->ir_rmt_port; 205 fl6.fl6_sport = htons(ireq->ir_num); 206 security_req_classify_flow(req, flowi6_to_flowi(&fl6)); 207 208 209 rcu_read_lock(); 210 final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final); 211 rcu_read_unlock(); 212 213 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 214 if (IS_ERR(dst)) { 215 err = PTR_ERR(dst); 216 dst = NULL; 217 goto done; 218 } 219 220 skb = dccp_make_response(sk, dst, req); 221 if (skb != NULL) { 222 struct dccp_hdr *dh = dccp_hdr(skb); 223 struct ipv6_txoptions *opt; 224 225 dh->dccph_checksum = dccp_v6_csum_finish(skb, 226 &ireq->ir_v6_loc_addr, 227 &ireq->ir_v6_rmt_addr); 228 fl6.daddr = ireq->ir_v6_rmt_addr; 229 rcu_read_lock(); 230 opt = ireq->ipv6_opt; 231 if (!opt) 232 opt = rcu_dereference(np->opt); 233 err = ip6_xmit(sk, skb, &fl6, sk->sk_mark, opt, np->tclass, 234 sk->sk_priority); 235 rcu_read_unlock(); 236 err = net_xmit_eval(err); 237 } 238 239 done: 240 dst_release(dst); 241 return err; 242 } 243 244 static void dccp_v6_reqsk_destructor(struct request_sock *req) 245 { 246 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); 247 kfree(inet_rsk(req)->ipv6_opt); 248 kfree_skb(inet_rsk(req)->pktopts); 249 } 250 251 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) 252 { 253 const struct ipv6hdr *rxip6h; 254 struct sk_buff *skb; 255 struct flowi6 fl6; 256 struct net *net = dev_net(skb_dst(rxskb)->dev); 257 struct sock *ctl_sk = net->dccp.v6_ctl_sk; 258 struct dst_entry *dst; 259 260 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) 261 return; 262 263 if (!ipv6_unicast_destination(rxskb)) 264 return; 265 266 skb = dccp_ctl_make_reset(ctl_sk, rxskb); 267 if (skb == NULL) 268 return; 269 270 rxip6h = ipv6_hdr(rxskb); 271 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr, 272 &rxip6h->daddr); 273 274 memset(&fl6, 0, sizeof(fl6)); 275 fl6.daddr = rxip6h->saddr; 276 fl6.saddr = rxip6h->daddr; 277 278 fl6.flowi6_proto = IPPROTO_DCCP; 279 fl6.flowi6_oif = inet6_iif(rxskb); 280 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport; 281 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport; 282 security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6)); 283 284 /* sk = NULL, but it is safe for now. RST socket required. */ 285 dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL); 286 if (!IS_ERR(dst)) { 287 skb_dst_set(skb, dst); 288 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0, 0); 289 DCCP_INC_STATS(DCCP_MIB_OUTSEGS); 290 DCCP_INC_STATS(DCCP_MIB_OUTRSTS); 291 return; 292 } 293 294 kfree_skb(skb); 295 } 296 297 static struct request_sock_ops dccp6_request_sock_ops = { 298 .family = AF_INET6, 299 .obj_size = sizeof(struct dccp6_request_sock), 300 .rtx_syn_ack = dccp_v6_send_response, 301 .send_ack = dccp_reqsk_send_ack, 302 .destructor = dccp_v6_reqsk_destructor, 303 .send_reset = dccp_v6_ctl_send_reset, 304 .syn_ack_timeout = dccp_syn_ack_timeout, 305 }; 306 307 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 308 { 309 struct request_sock *req; 310 struct dccp_request_sock *dreq; 311 struct inet_request_sock *ireq; 312 struct ipv6_pinfo *np = inet6_sk(sk); 313 const __be32 service = dccp_hdr_request(skb)->dccph_req_service; 314 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); 315 316 if (skb->protocol == htons(ETH_P_IP)) 317 return dccp_v4_conn_request(sk, skb); 318 319 if (!ipv6_unicast_destination(skb)) 320 return 0; /* discard, don't send a reset here */ 321 322 if (dccp_bad_service_code(sk, service)) { 323 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; 324 goto drop; 325 } 326 /* 327 * There are no SYN attacks on IPv6, yet... 328 */ 329 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 330 if (inet_csk_reqsk_queue_is_full(sk)) 331 goto drop; 332 333 if (sk_acceptq_is_full(sk)) 334 goto drop; 335 336 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true); 337 if (req == NULL) 338 goto drop; 339 340 if (dccp_reqsk_init(req, dccp_sk(sk), skb)) 341 goto drop_and_free; 342 343 dreq = dccp_rsk(req); 344 if (dccp_parse_options(sk, dreq, skb)) 345 goto drop_and_free; 346 347 if (security_inet_conn_request(sk, skb, req)) 348 goto drop_and_free; 349 350 ireq = inet_rsk(req); 351 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; 352 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; 353 ireq->ireq_family = AF_INET6; 354 ireq->ir_mark = inet_request_mark(sk, skb); 355 356 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) || 357 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || 358 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { 359 refcount_inc(&skb->users); 360 ireq->pktopts = skb; 361 } 362 ireq->ir_iif = sk->sk_bound_dev_if; 363 364 /* So that link locals have meaning */ 365 if (!sk->sk_bound_dev_if && 366 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 367 ireq->ir_iif = inet6_iif(skb); 368 369 /* 370 * Step 3: Process LISTEN state 371 * 372 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 373 * 374 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 375 */ 376 dreq->dreq_isr = dcb->dccpd_seq; 377 dreq->dreq_gsr = dreq->dreq_isr; 378 dreq->dreq_iss = dccp_v6_init_sequence(skb); 379 dreq->dreq_gss = dreq->dreq_iss; 380 dreq->dreq_service = service; 381 382 if (dccp_v6_send_response(sk, req)) 383 goto drop_and_free; 384 385 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 386 reqsk_put(req); 387 return 0; 388 389 drop_and_free: 390 reqsk_free(req); 391 drop: 392 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 393 return -1; 394 } 395 396 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 397 struct sk_buff *skb, 398 struct request_sock *req, 399 struct dst_entry *dst, 400 struct request_sock *req_unhash, 401 bool *own_req) 402 { 403 struct inet_request_sock *ireq = inet_rsk(req); 404 struct ipv6_pinfo *newnp; 405 const struct ipv6_pinfo *np = inet6_sk(sk); 406 struct ipv6_txoptions *opt; 407 struct inet_sock *newinet; 408 struct dccp6_sock *newdp6; 409 struct sock *newsk; 410 411 if (skb->protocol == htons(ETH_P_IP)) { 412 /* 413 * v6 mapped 414 */ 415 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 416 req_unhash, own_req); 417 if (newsk == NULL) 418 return NULL; 419 420 newdp6 = (struct dccp6_sock *)newsk; 421 newinet = inet_sk(newsk); 422 newinet->pinet6 = &newdp6->inet6; 423 newnp = inet6_sk(newsk); 424 425 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 426 427 newnp->saddr = newsk->sk_v6_rcv_saddr; 428 429 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 430 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 431 newnp->pktoptions = NULL; 432 newnp->opt = NULL; 433 newnp->ipv6_mc_list = NULL; 434 newnp->ipv6_ac_list = NULL; 435 newnp->ipv6_fl_list = NULL; 436 newnp->mcast_oif = inet_iif(skb); 437 newnp->mcast_hops = ip_hdr(skb)->ttl; 438 439 /* 440 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 441 * here, dccp_create_openreq_child now does this for us, see the comment in 442 * that function for the gory details. -acme 443 */ 444 445 /* It is tricky place. Until this moment IPv4 tcp 446 worked with IPv6 icsk.icsk_af_ops. 447 Sync it now. 448 */ 449 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 450 451 return newsk; 452 } 453 454 455 if (sk_acceptq_is_full(sk)) 456 goto out_overflow; 457 458 if (!dst) { 459 struct flowi6 fl6; 460 461 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 462 if (!dst) 463 goto out; 464 } 465 466 newsk = dccp_create_openreq_child(sk, req, skb); 467 if (newsk == NULL) 468 goto out_nonewsk; 469 470 /* 471 * No need to charge this sock to the relevant IPv6 refcnt debug socks 472 * count here, dccp_create_openreq_child now does this for us, see the 473 * comment in that function for the gory details. -acme 474 */ 475 476 ip6_dst_store(newsk, dst, NULL, NULL); 477 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 478 NETIF_F_TSO); 479 newdp6 = (struct dccp6_sock *)newsk; 480 newinet = inet_sk(newsk); 481 newinet->pinet6 = &newdp6->inet6; 482 newnp = inet6_sk(newsk); 483 484 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 485 486 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 487 newnp->saddr = ireq->ir_v6_loc_addr; 488 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 489 newsk->sk_bound_dev_if = ireq->ir_iif; 490 491 /* Now IPv6 options... 492 493 First: no IPv4 options. 494 */ 495 newinet->inet_opt = NULL; 496 497 /* Clone RX bits */ 498 newnp->rxopt.all = np->rxopt.all; 499 500 newnp->ipv6_mc_list = NULL; 501 newnp->ipv6_ac_list = NULL; 502 newnp->ipv6_fl_list = NULL; 503 newnp->pktoptions = NULL; 504 newnp->opt = NULL; 505 newnp->mcast_oif = inet6_iif(skb); 506 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 507 508 /* 509 * Clone native IPv6 options from listening socket (if any) 510 * 511 * Yes, keeping reference count would be much more clever, but we make 512 * one more one thing there: reattach optmem to newsk. 513 */ 514 opt = ireq->ipv6_opt; 515 if (!opt) 516 opt = rcu_dereference(np->opt); 517 if (opt) { 518 opt = ipv6_dup_options(newsk, opt); 519 RCU_INIT_POINTER(newnp->opt, opt); 520 } 521 inet_csk(newsk)->icsk_ext_hdr_len = 0; 522 if (opt) 523 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 524 opt->opt_flen; 525 526 dccp_sync_mss(newsk, dst_mtu(dst)); 527 528 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 529 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 530 531 if (__inet_inherit_port(sk, newsk) < 0) { 532 inet_csk_prepare_forced_close(newsk); 533 dccp_done(newsk); 534 goto out; 535 } 536 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); 537 /* Clone pktoptions received with SYN, if we own the req */ 538 if (*own_req && ireq->pktopts) { 539 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC); 540 consume_skb(ireq->pktopts); 541 ireq->pktopts = NULL; 542 if (newnp->pktoptions) 543 skb_set_owner_r(newnp->pktoptions, newsk); 544 } 545 546 return newsk; 547 548 out_overflow: 549 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 550 out_nonewsk: 551 dst_release(dst); 552 out: 553 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 554 return NULL; 555 } 556 557 /* The socket must have it's spinlock held when we get 558 * here. 559 * 560 * We have a potential double-lock case here, so even when 561 * doing backlog processing we use the BH locking scheme. 562 * This is because we cannot sleep with the original spinlock 563 * held. 564 */ 565 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 566 { 567 struct ipv6_pinfo *np = inet6_sk(sk); 568 struct sk_buff *opt_skb = NULL; 569 570 /* Imagine: socket is IPv6. IPv4 packet arrives, 571 goes to IPv4 receive handler and backlogged. 572 From backlog it always goes here. Kerboom... 573 Fortunately, dccp_rcv_established and rcv_established 574 handle them correctly, but it is not case with 575 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 576 */ 577 578 if (skb->protocol == htons(ETH_P_IP)) 579 return dccp_v4_do_rcv(sk, skb); 580 581 if (sk_filter(sk, skb)) 582 goto discard; 583 584 /* 585 * socket locking is here for SMP purposes as backlog rcv is currently 586 * called with bh processing disabled. 587 */ 588 589 /* Do Stevens' IPV6_PKTOPTIONS. 590 591 Yes, guys, it is the only place in our code, where we 592 may make it not affecting IPv4. 593 The rest of code is protocol independent, 594 and I do not like idea to uglify IPv4. 595 596 Actually, all the idea behind IPV6_PKTOPTIONS 597 looks not very well thought. For now we latch 598 options, received in the last packet, enqueued 599 by tcp. Feel free to propose better solution. 600 --ANK (980728) 601 */ 602 if (np->rxopt.all) 603 opt_skb = skb_clone(skb, GFP_ATOMIC); 604 605 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 606 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 607 goto reset; 608 if (opt_skb) 609 goto ipv6_pktoptions; 610 return 0; 611 } 612 613 /* 614 * Step 3: Process LISTEN state 615 * If S.state == LISTEN, 616 * If P.type == Request or P contains a valid Init Cookie option, 617 * (* Must scan the packet's options to check for Init 618 * Cookies. Only Init Cookies are processed here, 619 * however; other options are processed in Step 8. This 620 * scan need only be performed if the endpoint uses Init 621 * Cookies *) 622 * (* Generate a new socket and switch to that socket *) 623 * Set S := new socket for this port pair 624 * S.state = RESPOND 625 * Choose S.ISS (initial seqno) or set from Init Cookies 626 * Initialize S.GAR := S.ISS 627 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 628 * Continue with S.state == RESPOND 629 * (* A Response packet will be generated in Step 11 *) 630 * Otherwise, 631 * Generate Reset(No Connection) unless P.type == Reset 632 * Drop packet and return 633 * 634 * NOTE: the check for the packet types is done in 635 * dccp_rcv_state_process 636 */ 637 638 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 639 goto reset; 640 if (opt_skb) 641 goto ipv6_pktoptions; 642 return 0; 643 644 reset: 645 dccp_v6_ctl_send_reset(sk, skb); 646 discard: 647 if (opt_skb != NULL) 648 __kfree_skb(opt_skb); 649 kfree_skb(skb); 650 return 0; 651 652 /* Handling IPV6_PKTOPTIONS skb the similar 653 * way it's done for net/ipv6/tcp_ipv6.c 654 */ 655 ipv6_pktoptions: 656 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) { 657 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) 658 np->mcast_oif = inet6_iif(opt_skb); 659 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) 660 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit; 661 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) 662 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); 663 if (np->repflow) 664 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb)); 665 if (ipv6_opt_accepted(sk, opt_skb, 666 &DCCP_SKB_CB(opt_skb)->header.h6)) { 667 skb_set_owner_r(opt_skb, sk); 668 memmove(IP6CB(opt_skb), 669 &DCCP_SKB_CB(opt_skb)->header.h6, 670 sizeof(struct inet6_skb_parm)); 671 opt_skb = xchg(&np->pktoptions, opt_skb); 672 } else { 673 __kfree_skb(opt_skb); 674 opt_skb = xchg(&np->pktoptions, NULL); 675 } 676 } 677 678 kfree_skb(opt_skb); 679 return 0; 680 } 681 682 static int dccp_v6_rcv(struct sk_buff *skb) 683 { 684 const struct dccp_hdr *dh; 685 bool refcounted; 686 struct sock *sk; 687 int min_cov; 688 689 /* Step 1: Check header basics */ 690 691 if (dccp_invalid_packet(skb)) 692 goto discard_it; 693 694 /* Step 1: If header checksum is incorrect, drop packet and return. */ 695 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, 696 &ipv6_hdr(skb)->daddr)) { 697 DCCP_WARN("dropped packet with invalid checksum\n"); 698 goto discard_it; 699 } 700 701 dh = dccp_hdr(skb); 702 703 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); 704 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; 705 706 if (dccp_packet_without_ack(skb)) 707 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; 708 else 709 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); 710 711 lookup: 712 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), 713 dh->dccph_sport, dh->dccph_dport, 714 inet6_iif(skb), 0, &refcounted); 715 if (!sk) { 716 dccp_pr_debug("failed to look up flow ID in table and " 717 "get corresponding socket\n"); 718 goto no_dccp_socket; 719 } 720 721 /* 722 * Step 2: 723 * ... or S.state == TIMEWAIT, 724 * Generate Reset(No Connection) unless P.type == Reset 725 * Drop packet and return 726 */ 727 if (sk->sk_state == DCCP_TIME_WAIT) { 728 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); 729 inet_twsk_put(inet_twsk(sk)); 730 goto no_dccp_socket; 731 } 732 733 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 734 struct request_sock *req = inet_reqsk(sk); 735 struct sock *nsk; 736 737 sk = req->rsk_listener; 738 if (unlikely(sk->sk_state != DCCP_LISTEN)) { 739 inet_csk_reqsk_queue_drop_and_put(sk, req); 740 goto lookup; 741 } 742 sock_hold(sk); 743 refcounted = true; 744 nsk = dccp_check_req(sk, skb, req); 745 if (!nsk) { 746 reqsk_put(req); 747 goto discard_and_relse; 748 } 749 if (nsk == sk) { 750 reqsk_put(req); 751 } else if (dccp_child_process(sk, nsk, skb)) { 752 dccp_v6_ctl_send_reset(sk, skb); 753 goto discard_and_relse; 754 } else { 755 sock_put(sk); 756 return 0; 757 } 758 } 759 /* 760 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage 761 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted 762 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov 763 */ 764 min_cov = dccp_sk(sk)->dccps_pcrlen; 765 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { 766 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", 767 dh->dccph_cscov, min_cov); 768 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ 769 goto discard_and_relse; 770 } 771 772 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 773 goto discard_and_relse; 774 775 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, 776 refcounted) ? -1 : 0; 777 778 no_dccp_socket: 779 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 780 goto discard_it; 781 /* 782 * Step 2: 783 * If no socket ... 784 * Generate Reset(No Connection) unless P.type == Reset 785 * Drop packet and return 786 */ 787 if (dh->dccph_type != DCCP_PKT_RESET) { 788 DCCP_SKB_CB(skb)->dccpd_reset_code = 789 DCCP_RESET_CODE_NO_CONNECTION; 790 dccp_v6_ctl_send_reset(sk, skb); 791 } 792 793 discard_it: 794 kfree_skb(skb); 795 return 0; 796 797 discard_and_relse: 798 if (refcounted) 799 sock_put(sk); 800 goto discard_it; 801 } 802 803 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 804 int addr_len) 805 { 806 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 807 struct inet_connection_sock *icsk = inet_csk(sk); 808 struct inet_sock *inet = inet_sk(sk); 809 struct ipv6_pinfo *np = inet6_sk(sk); 810 struct dccp_sock *dp = dccp_sk(sk); 811 struct in6_addr *saddr = NULL, *final_p, final; 812 struct ipv6_txoptions *opt; 813 struct flowi6 fl6; 814 struct dst_entry *dst; 815 int addr_type; 816 int err; 817 818 dp->dccps_role = DCCP_ROLE_CLIENT; 819 820 if (addr_len < SIN6_LEN_RFC2133) 821 return -EINVAL; 822 823 if (usin->sin6_family != AF_INET6) 824 return -EAFNOSUPPORT; 825 826 memset(&fl6, 0, sizeof(fl6)); 827 828 if (np->sndflow) { 829 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 830 IP6_ECN_flow_init(fl6.flowlabel); 831 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 832 struct ip6_flowlabel *flowlabel; 833 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 834 if (IS_ERR(flowlabel)) 835 return -EINVAL; 836 fl6_sock_release(flowlabel); 837 } 838 } 839 /* 840 * connect() to INADDR_ANY means loopback (BSD'ism). 841 */ 842 if (ipv6_addr_any(&usin->sin6_addr)) 843 usin->sin6_addr.s6_addr[15] = 1; 844 845 addr_type = ipv6_addr_type(&usin->sin6_addr); 846 847 if (addr_type & IPV6_ADDR_MULTICAST) 848 return -ENETUNREACH; 849 850 if (addr_type & IPV6_ADDR_LINKLOCAL) { 851 if (addr_len >= sizeof(struct sockaddr_in6) && 852 usin->sin6_scope_id) { 853 /* If interface is set while binding, indices 854 * must coincide. 855 */ 856 if (sk->sk_bound_dev_if && 857 sk->sk_bound_dev_if != usin->sin6_scope_id) 858 return -EINVAL; 859 860 sk->sk_bound_dev_if = usin->sin6_scope_id; 861 } 862 863 /* Connect to link-local address requires an interface */ 864 if (!sk->sk_bound_dev_if) 865 return -EINVAL; 866 } 867 868 sk->sk_v6_daddr = usin->sin6_addr; 869 np->flow_label = fl6.flowlabel; 870 871 /* 872 * DCCP over IPv4 873 */ 874 if (addr_type == IPV6_ADDR_MAPPED) { 875 u32 exthdrlen = icsk->icsk_ext_hdr_len; 876 struct sockaddr_in sin; 877 878 SOCK_DEBUG(sk, "connect: ipv4 mapped\n"); 879 880 if (__ipv6_only_sock(sk)) 881 return -ENETUNREACH; 882 883 sin.sin_family = AF_INET; 884 sin.sin_port = usin->sin6_port; 885 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 886 887 icsk->icsk_af_ops = &dccp_ipv6_mapped; 888 sk->sk_backlog_rcv = dccp_v4_do_rcv; 889 890 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 891 if (err) { 892 icsk->icsk_ext_hdr_len = exthdrlen; 893 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 894 sk->sk_backlog_rcv = dccp_v6_do_rcv; 895 goto failure; 896 } 897 np->saddr = sk->sk_v6_rcv_saddr; 898 return err; 899 } 900 901 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 902 saddr = &sk->sk_v6_rcv_saddr; 903 904 fl6.flowi6_proto = IPPROTO_DCCP; 905 fl6.daddr = sk->sk_v6_daddr; 906 fl6.saddr = saddr ? *saddr : np->saddr; 907 fl6.flowi6_oif = sk->sk_bound_dev_if; 908 fl6.fl6_dport = usin->sin6_port; 909 fl6.fl6_sport = inet->inet_sport; 910 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); 911 912 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 913 final_p = fl6_update_dst(&fl6, opt, &final); 914 915 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 916 if (IS_ERR(dst)) { 917 err = PTR_ERR(dst); 918 goto failure; 919 } 920 921 if (saddr == NULL) { 922 saddr = &fl6.saddr; 923 sk->sk_v6_rcv_saddr = *saddr; 924 } 925 926 /* set the source address */ 927 np->saddr = *saddr; 928 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 929 930 ip6_dst_store(sk, dst, NULL, NULL); 931 932 icsk->icsk_ext_hdr_len = 0; 933 if (opt) 934 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; 935 936 inet->inet_dport = usin->sin6_port; 937 938 dccp_set_state(sk, DCCP_REQUESTING); 939 err = inet6_hash_connect(&dccp_death_row, sk); 940 if (err) 941 goto late_failure; 942 943 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 944 sk->sk_v6_daddr.s6_addr32, 945 inet->inet_sport, 946 inet->inet_dport); 947 err = dccp_connect(sk); 948 if (err) 949 goto late_failure; 950 951 return 0; 952 953 late_failure: 954 dccp_set_state(sk, DCCP_CLOSED); 955 __sk_dst_reset(sk); 956 failure: 957 inet->inet_dport = 0; 958 sk->sk_route_caps = 0; 959 return err; 960 } 961 962 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 963 .queue_xmit = inet6_csk_xmit, 964 .send_check = dccp_v6_send_check, 965 .rebuild_header = inet6_sk_rebuild_header, 966 .conn_request = dccp_v6_conn_request, 967 .syn_recv_sock = dccp_v6_request_recv_sock, 968 .net_header_len = sizeof(struct ipv6hdr), 969 .setsockopt = ipv6_setsockopt, 970 .getsockopt = ipv6_getsockopt, 971 .addr2sockaddr = inet6_csk_addr2sockaddr, 972 .sockaddr_len = sizeof(struct sockaddr_in6), 973 }; 974 975 /* 976 * DCCP over IPv4 via INET6 API 977 */ 978 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 979 .queue_xmit = ip_queue_xmit, 980 .send_check = dccp_v4_send_check, 981 .rebuild_header = inet_sk_rebuild_header, 982 .conn_request = dccp_v6_conn_request, 983 .syn_recv_sock = dccp_v6_request_recv_sock, 984 .net_header_len = sizeof(struct iphdr), 985 .setsockopt = ipv6_setsockopt, 986 .getsockopt = ipv6_getsockopt, 987 .addr2sockaddr = inet6_csk_addr2sockaddr, 988 .sockaddr_len = sizeof(struct sockaddr_in6), 989 }; 990 991 /* NOTE: A lot of things set to zero explicitly by call to 992 * sk_alloc() so need not be done here. 993 */ 994 static int dccp_v6_init_sock(struct sock *sk) 995 { 996 static __u8 dccp_v6_ctl_sock_initialized; 997 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 998 999 if (err == 0) { 1000 if (unlikely(!dccp_v6_ctl_sock_initialized)) 1001 dccp_v6_ctl_sock_initialized = 1; 1002 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 1003 } 1004 1005 return err; 1006 } 1007 1008 static void dccp_v6_destroy_sock(struct sock *sk) 1009 { 1010 dccp_destroy_sock(sk); 1011 inet6_destroy_sock(sk); 1012 } 1013 1014 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 1015 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 1016 }; 1017 1018 static struct proto dccp_v6_prot = { 1019 .name = "DCCPv6", 1020 .owner = THIS_MODULE, 1021 .close = dccp_close, 1022 .connect = dccp_v6_connect, 1023 .disconnect = dccp_disconnect, 1024 .ioctl = dccp_ioctl, 1025 .init = dccp_v6_init_sock, 1026 .setsockopt = dccp_setsockopt, 1027 .getsockopt = dccp_getsockopt, 1028 .sendmsg = dccp_sendmsg, 1029 .recvmsg = dccp_recvmsg, 1030 .backlog_rcv = dccp_v6_do_rcv, 1031 .hash = inet6_hash, 1032 .unhash = inet_unhash, 1033 .accept = inet_csk_accept, 1034 .get_port = inet_csk_get_port, 1035 .shutdown = dccp_shutdown, 1036 .destroy = dccp_v6_destroy_sock, 1037 .orphan_count = &dccp_orphan_count, 1038 .max_header = MAX_DCCP_HEADER, 1039 .obj_size = sizeof(struct dccp6_sock), 1040 .slab_flags = SLAB_TYPESAFE_BY_RCU, 1041 .rsk_prot = &dccp6_request_sock_ops, 1042 .twsk_prot = &dccp6_timewait_sock_ops, 1043 .h.hashinfo = &dccp_hashinfo, 1044 }; 1045 1046 static const struct inet6_protocol dccp_v6_protocol = { 1047 .handler = dccp_v6_rcv, 1048 .err_handler = dccp_v6_err, 1049 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1050 }; 1051 1052 static const struct proto_ops inet6_dccp_ops = { 1053 .family = PF_INET6, 1054 .owner = THIS_MODULE, 1055 .release = inet6_release, 1056 .bind = inet6_bind, 1057 .connect = inet_stream_connect, 1058 .socketpair = sock_no_socketpair, 1059 .accept = inet_accept, 1060 .getname = inet6_getname, 1061 .poll = dccp_poll, 1062 .ioctl = inet6_ioctl, 1063 .gettstamp = sock_gettstamp, 1064 .listen = inet_dccp_listen, 1065 .shutdown = inet_shutdown, 1066 .setsockopt = sock_common_setsockopt, 1067 .getsockopt = sock_common_getsockopt, 1068 .sendmsg = inet_sendmsg, 1069 .recvmsg = sock_common_recvmsg, 1070 .mmap = sock_no_mmap, 1071 .sendpage = sock_no_sendpage, 1072 #ifdef CONFIG_COMPAT 1073 .compat_ioctl = inet6_compat_ioctl, 1074 #endif 1075 }; 1076 1077 static struct inet_protosw dccp_v6_protosw = { 1078 .type = SOCK_DCCP, 1079 .protocol = IPPROTO_DCCP, 1080 .prot = &dccp_v6_prot, 1081 .ops = &inet6_dccp_ops, 1082 .flags = INET_PROTOSW_ICSK, 1083 }; 1084 1085 static int __net_init dccp_v6_init_net(struct net *net) 1086 { 1087 if (dccp_hashinfo.bhash == NULL) 1088 return -ESOCKTNOSUPPORT; 1089 1090 return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6, 1091 SOCK_DCCP, IPPROTO_DCCP, net); 1092 } 1093 1094 static void __net_exit dccp_v6_exit_net(struct net *net) 1095 { 1096 inet_ctl_sock_destroy(net->dccp.v6_ctl_sk); 1097 } 1098 1099 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list) 1100 { 1101 inet_twsk_purge(&dccp_hashinfo, AF_INET6); 1102 } 1103 1104 static struct pernet_operations dccp_v6_ops = { 1105 .init = dccp_v6_init_net, 1106 .exit = dccp_v6_exit_net, 1107 .exit_batch = dccp_v6_exit_batch, 1108 }; 1109 1110 static int __init dccp_v6_init(void) 1111 { 1112 int err = proto_register(&dccp_v6_prot, 1); 1113 1114 if (err) 1115 goto out; 1116 1117 inet6_register_protosw(&dccp_v6_protosw); 1118 1119 err = register_pernet_subsys(&dccp_v6_ops); 1120 if (err) 1121 goto out_destroy_ctl_sock; 1122 1123 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1124 if (err) 1125 goto out_unregister_proto; 1126 1127 out: 1128 return err; 1129 out_unregister_proto: 1130 unregister_pernet_subsys(&dccp_v6_ops); 1131 out_destroy_ctl_sock: 1132 inet6_unregister_protosw(&dccp_v6_protosw); 1133 proto_unregister(&dccp_v6_prot); 1134 goto out; 1135 } 1136 1137 static void __exit dccp_v6_exit(void) 1138 { 1139 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1140 unregister_pernet_subsys(&dccp_v6_ops); 1141 inet6_unregister_protosw(&dccp_v6_protosw); 1142 proto_unregister(&dccp_v6_prot); 1143 } 1144 1145 module_init(dccp_v6_init); 1146 module_exit(dccp_v6_exit); 1147 1148 /* 1149 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) 1150 * values directly, Also cover the case where the protocol is not specified, 1151 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP 1152 */ 1153 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6); 1154 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6); 1155 MODULE_LICENSE("GPL"); 1156 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>"); 1157 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol"); 1158