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(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 rcu_read_unlock(); 235 err = net_xmit_eval(err); 236 } 237 238 done: 239 dst_release(dst); 240 return err; 241 } 242 243 static void dccp_v6_reqsk_destructor(struct request_sock *req) 244 { 245 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); 246 kfree(inet_rsk(req)->ipv6_opt); 247 kfree_skb(inet_rsk(req)->pktopts); 248 } 249 250 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) 251 { 252 const struct ipv6hdr *rxip6h; 253 struct sk_buff *skb; 254 struct flowi6 fl6; 255 struct net *net = dev_net(skb_dst(rxskb)->dev); 256 struct sock *ctl_sk = net->dccp.v6_ctl_sk; 257 struct dst_entry *dst; 258 259 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) 260 return; 261 262 if (!ipv6_unicast_destination(rxskb)) 263 return; 264 265 skb = dccp_ctl_make_reset(ctl_sk, rxskb); 266 if (skb == NULL) 267 return; 268 269 rxip6h = ipv6_hdr(rxskb); 270 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr, 271 &rxip6h->daddr); 272 273 memset(&fl6, 0, sizeof(fl6)); 274 fl6.daddr = rxip6h->saddr; 275 fl6.saddr = rxip6h->daddr; 276 277 fl6.flowi6_proto = IPPROTO_DCCP; 278 fl6.flowi6_oif = inet6_iif(rxskb); 279 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport; 280 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport; 281 security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6)); 282 283 /* sk = NULL, but it is safe for now. RST socket required. */ 284 dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL); 285 if (!IS_ERR(dst)) { 286 skb_dst_set(skb, dst); 287 ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0); 288 DCCP_INC_STATS(DCCP_MIB_OUTSEGS); 289 DCCP_INC_STATS(DCCP_MIB_OUTRSTS); 290 return; 291 } 292 293 kfree_skb(skb); 294 } 295 296 static struct request_sock_ops dccp6_request_sock_ops = { 297 .family = AF_INET6, 298 .obj_size = sizeof(struct dccp6_request_sock), 299 .rtx_syn_ack = dccp_v6_send_response, 300 .send_ack = dccp_reqsk_send_ack, 301 .destructor = dccp_v6_reqsk_destructor, 302 .send_reset = dccp_v6_ctl_send_reset, 303 .syn_ack_timeout = dccp_syn_ack_timeout, 304 }; 305 306 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 307 { 308 struct request_sock *req; 309 struct dccp_request_sock *dreq; 310 struct inet_request_sock *ireq; 311 struct ipv6_pinfo *np = inet6_sk(sk); 312 const __be32 service = dccp_hdr_request(skb)->dccph_req_service; 313 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); 314 315 if (skb->protocol == htons(ETH_P_IP)) 316 return dccp_v4_conn_request(sk, skb); 317 318 if (!ipv6_unicast_destination(skb)) 319 return 0; /* discard, don't send a reset here */ 320 321 if (dccp_bad_service_code(sk, service)) { 322 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; 323 goto drop; 324 } 325 /* 326 * There are no SYN attacks on IPv6, yet... 327 */ 328 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 329 if (inet_csk_reqsk_queue_is_full(sk)) 330 goto drop; 331 332 if (sk_acceptq_is_full(sk)) 333 goto drop; 334 335 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true); 336 if (req == NULL) 337 goto drop; 338 339 if (dccp_reqsk_init(req, dccp_sk(sk), skb)) 340 goto drop_and_free; 341 342 dreq = dccp_rsk(req); 343 if (dccp_parse_options(sk, dreq, skb)) 344 goto drop_and_free; 345 346 if (security_inet_conn_request(sk, skb, req)) 347 goto drop_and_free; 348 349 ireq = inet_rsk(req); 350 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; 351 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; 352 ireq->ireq_family = AF_INET6; 353 ireq->ir_mark = inet_request_mark(sk, skb); 354 355 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) || 356 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || 357 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { 358 refcount_inc(&skb->users); 359 ireq->pktopts = skb; 360 } 361 ireq->ir_iif = sk->sk_bound_dev_if; 362 363 /* So that link locals have meaning */ 364 if (!sk->sk_bound_dev_if && 365 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 366 ireq->ir_iif = inet6_iif(skb); 367 368 /* 369 * Step 3: Process LISTEN state 370 * 371 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 372 * 373 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 374 */ 375 dreq->dreq_isr = dcb->dccpd_seq; 376 dreq->dreq_gsr = dreq->dreq_isr; 377 dreq->dreq_iss = dccp_v6_init_sequence(skb); 378 dreq->dreq_gss = dreq->dreq_iss; 379 dreq->dreq_service = service; 380 381 if (dccp_v6_send_response(sk, req)) 382 goto drop_and_free; 383 384 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 385 reqsk_put(req); 386 return 0; 387 388 drop_and_free: 389 reqsk_free(req); 390 drop: 391 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS); 392 return -1; 393 } 394 395 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 396 struct sk_buff *skb, 397 struct request_sock *req, 398 struct dst_entry *dst, 399 struct request_sock *req_unhash, 400 bool *own_req) 401 { 402 struct inet_request_sock *ireq = inet_rsk(req); 403 struct ipv6_pinfo *newnp; 404 const struct ipv6_pinfo *np = inet6_sk(sk); 405 struct ipv6_txoptions *opt; 406 struct inet_sock *newinet; 407 struct dccp6_sock *newdp6; 408 struct sock *newsk; 409 410 if (skb->protocol == htons(ETH_P_IP)) { 411 /* 412 * v6 mapped 413 */ 414 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 415 req_unhash, own_req); 416 if (newsk == NULL) 417 return NULL; 418 419 newdp6 = (struct dccp6_sock *)newsk; 420 newinet = inet_sk(newsk); 421 newinet->pinet6 = &newdp6->inet6; 422 newnp = inet6_sk(newsk); 423 424 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 425 426 newnp->saddr = newsk->sk_v6_rcv_saddr; 427 428 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 429 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 430 newnp->pktoptions = NULL; 431 newnp->opt = NULL; 432 newnp->ipv6_mc_list = NULL; 433 newnp->ipv6_ac_list = NULL; 434 newnp->ipv6_fl_list = NULL; 435 newnp->mcast_oif = inet_iif(skb); 436 newnp->mcast_hops = ip_hdr(skb)->ttl; 437 438 /* 439 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 440 * here, dccp_create_openreq_child now does this for us, see the comment in 441 * that function for the gory details. -acme 442 */ 443 444 /* It is tricky place. Until this moment IPv4 tcp 445 worked with IPv6 icsk.icsk_af_ops. 446 Sync it now. 447 */ 448 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 449 450 return newsk; 451 } 452 453 454 if (sk_acceptq_is_full(sk)) 455 goto out_overflow; 456 457 if (!dst) { 458 struct flowi6 fl6; 459 460 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 461 if (!dst) 462 goto out; 463 } 464 465 newsk = dccp_create_openreq_child(sk, req, skb); 466 if (newsk == NULL) 467 goto out_nonewsk; 468 469 /* 470 * No need to charge this sock to the relevant IPv6 refcnt debug socks 471 * count here, dccp_create_openreq_child now does this for us, see the 472 * comment in that function for the gory details. -acme 473 */ 474 475 ip6_dst_store(newsk, dst, NULL, NULL); 476 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 477 NETIF_F_TSO); 478 newdp6 = (struct dccp6_sock *)newsk; 479 newinet = inet_sk(newsk); 480 newinet->pinet6 = &newdp6->inet6; 481 newnp = inet6_sk(newsk); 482 483 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 484 485 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 486 newnp->saddr = ireq->ir_v6_loc_addr; 487 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 488 newsk->sk_bound_dev_if = ireq->ir_iif; 489 490 /* Now IPv6 options... 491 492 First: no IPv4 options. 493 */ 494 newinet->inet_opt = NULL; 495 496 /* Clone RX bits */ 497 newnp->rxopt.all = np->rxopt.all; 498 499 newnp->ipv6_mc_list = NULL; 500 newnp->ipv6_ac_list = NULL; 501 newnp->ipv6_fl_list = NULL; 502 newnp->pktoptions = NULL; 503 newnp->opt = NULL; 504 newnp->mcast_oif = inet6_iif(skb); 505 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 506 507 /* 508 * Clone native IPv6 options from listening socket (if any) 509 * 510 * Yes, keeping reference count would be much more clever, but we make 511 * one more one thing there: reattach optmem to newsk. 512 */ 513 opt = ireq->ipv6_opt; 514 if (!opt) 515 opt = rcu_dereference(np->opt); 516 if (opt) { 517 opt = ipv6_dup_options(newsk, opt); 518 RCU_INIT_POINTER(newnp->opt, opt); 519 } 520 inet_csk(newsk)->icsk_ext_hdr_len = 0; 521 if (opt) 522 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 523 opt->opt_flen; 524 525 dccp_sync_mss(newsk, dst_mtu(dst)); 526 527 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 528 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 529 530 if (__inet_inherit_port(sk, newsk) < 0) { 531 inet_csk_prepare_forced_close(newsk); 532 dccp_done(newsk); 533 goto out; 534 } 535 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); 536 /* Clone pktoptions received with SYN, if we own the req */ 537 if (*own_req && ireq->pktopts) { 538 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC); 539 consume_skb(ireq->pktopts); 540 ireq->pktopts = NULL; 541 if (newnp->pktoptions) 542 skb_set_owner_r(newnp->pktoptions, newsk); 543 } 544 545 return newsk; 546 547 out_overflow: 548 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 549 out_nonewsk: 550 dst_release(dst); 551 out: 552 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS); 553 return NULL; 554 } 555 556 /* The socket must have it's spinlock held when we get 557 * here. 558 * 559 * We have a potential double-lock case here, so even when 560 * doing backlog processing we use the BH locking scheme. 561 * This is because we cannot sleep with the original spinlock 562 * held. 563 */ 564 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 565 { 566 struct ipv6_pinfo *np = inet6_sk(sk); 567 struct sk_buff *opt_skb = NULL; 568 569 /* Imagine: socket is IPv6. IPv4 packet arrives, 570 goes to IPv4 receive handler and backlogged. 571 From backlog it always goes here. Kerboom... 572 Fortunately, dccp_rcv_established and rcv_established 573 handle them correctly, but it is not case with 574 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 575 */ 576 577 if (skb->protocol == htons(ETH_P_IP)) 578 return dccp_v4_do_rcv(sk, skb); 579 580 if (sk_filter(sk, skb)) 581 goto discard; 582 583 /* 584 * socket locking is here for SMP purposes as backlog rcv is currently 585 * called with bh processing disabled. 586 */ 587 588 /* Do Stevens' IPV6_PKTOPTIONS. 589 590 Yes, guys, it is the only place in our code, where we 591 may make it not affecting IPv4. 592 The rest of code is protocol independent, 593 and I do not like idea to uglify IPv4. 594 595 Actually, all the idea behind IPV6_PKTOPTIONS 596 looks not very well thought. For now we latch 597 options, received in the last packet, enqueued 598 by tcp. Feel free to propose better solution. 599 --ANK (980728) 600 */ 601 if (np->rxopt.all) 602 opt_skb = skb_clone(skb, GFP_ATOMIC); 603 604 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 605 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 606 goto reset; 607 if (opt_skb) 608 goto ipv6_pktoptions; 609 return 0; 610 } 611 612 /* 613 * Step 3: Process LISTEN state 614 * If S.state == LISTEN, 615 * If P.type == Request or P contains a valid Init Cookie option, 616 * (* Must scan the packet's options to check for Init 617 * Cookies. Only Init Cookies are processed here, 618 * however; other options are processed in Step 8. This 619 * scan need only be performed if the endpoint uses Init 620 * Cookies *) 621 * (* Generate a new socket and switch to that socket *) 622 * Set S := new socket for this port pair 623 * S.state = RESPOND 624 * Choose S.ISS (initial seqno) or set from Init Cookies 625 * Initialize S.GAR := S.ISS 626 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 627 * Continue with S.state == RESPOND 628 * (* A Response packet will be generated in Step 11 *) 629 * Otherwise, 630 * Generate Reset(No Connection) unless P.type == Reset 631 * Drop packet and return 632 * 633 * NOTE: the check for the packet types is done in 634 * dccp_rcv_state_process 635 */ 636 637 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 638 goto reset; 639 if (opt_skb) 640 goto ipv6_pktoptions; 641 return 0; 642 643 reset: 644 dccp_v6_ctl_send_reset(sk, skb); 645 discard: 646 if (opt_skb != NULL) 647 __kfree_skb(opt_skb); 648 kfree_skb(skb); 649 return 0; 650 651 /* Handling IPV6_PKTOPTIONS skb the similar 652 * way it's done for net/ipv6/tcp_ipv6.c 653 */ 654 ipv6_pktoptions: 655 if (!((1 << sk->sk_state) & (DCCPF_CLOSED | DCCPF_LISTEN))) { 656 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) 657 np->mcast_oif = inet6_iif(opt_skb); 658 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) 659 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit; 660 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) 661 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); 662 if (np->repflow) 663 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb)); 664 if (ipv6_opt_accepted(sk, opt_skb, 665 &DCCP_SKB_CB(opt_skb)->header.h6)) { 666 skb_set_owner_r(opt_skb, sk); 667 memmove(IP6CB(opt_skb), 668 &DCCP_SKB_CB(opt_skb)->header.h6, 669 sizeof(struct inet6_skb_parm)); 670 opt_skb = xchg(&np->pktoptions, opt_skb); 671 } else { 672 __kfree_skb(opt_skb); 673 opt_skb = xchg(&np->pktoptions, NULL); 674 } 675 } 676 677 kfree_skb(opt_skb); 678 return 0; 679 } 680 681 static int dccp_v6_rcv(struct sk_buff *skb) 682 { 683 const struct dccp_hdr *dh; 684 bool refcounted; 685 struct sock *sk; 686 int min_cov; 687 688 /* Step 1: Check header basics */ 689 690 if (dccp_invalid_packet(skb)) 691 goto discard_it; 692 693 /* Step 1: If header checksum is incorrect, drop packet and return. */ 694 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, 695 &ipv6_hdr(skb)->daddr)) { 696 DCCP_WARN("dropped packet with invalid checksum\n"); 697 goto discard_it; 698 } 699 700 dh = dccp_hdr(skb); 701 702 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); 703 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; 704 705 if (dccp_packet_without_ack(skb)) 706 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; 707 else 708 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); 709 710 lookup: 711 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), 712 dh->dccph_sport, dh->dccph_dport, 713 inet6_iif(skb), 0, &refcounted); 714 if (!sk) { 715 dccp_pr_debug("failed to look up flow ID in table and " 716 "get corresponding socket\n"); 717 goto no_dccp_socket; 718 } 719 720 /* 721 * Step 2: 722 * ... or S.state == TIMEWAIT, 723 * Generate Reset(No Connection) unless P.type == Reset 724 * Drop packet and return 725 */ 726 if (sk->sk_state == DCCP_TIME_WAIT) { 727 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); 728 inet_twsk_put(inet_twsk(sk)); 729 goto no_dccp_socket; 730 } 731 732 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 733 struct request_sock *req = inet_reqsk(sk); 734 struct sock *nsk; 735 736 sk = req->rsk_listener; 737 if (unlikely(sk->sk_state != DCCP_LISTEN)) { 738 inet_csk_reqsk_queue_drop_and_put(sk, req); 739 goto lookup; 740 } 741 sock_hold(sk); 742 refcounted = true; 743 nsk = dccp_check_req(sk, skb, req); 744 if (!nsk) { 745 reqsk_put(req); 746 goto discard_and_relse; 747 } 748 if (nsk == sk) { 749 reqsk_put(req); 750 } else if (dccp_child_process(sk, nsk, skb)) { 751 dccp_v6_ctl_send_reset(sk, skb); 752 goto discard_and_relse; 753 } else { 754 sock_put(sk); 755 return 0; 756 } 757 } 758 /* 759 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage 760 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted 761 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov 762 */ 763 min_cov = dccp_sk(sk)->dccps_pcrlen; 764 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { 765 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", 766 dh->dccph_cscov, min_cov); 767 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ 768 goto discard_and_relse; 769 } 770 771 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 772 goto discard_and_relse; 773 774 return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, 775 refcounted) ? -1 : 0; 776 777 no_dccp_socket: 778 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 779 goto discard_it; 780 /* 781 * Step 2: 782 * If no socket ... 783 * Generate Reset(No Connection) unless P.type == Reset 784 * Drop packet and return 785 */ 786 if (dh->dccph_type != DCCP_PKT_RESET) { 787 DCCP_SKB_CB(skb)->dccpd_reset_code = 788 DCCP_RESET_CODE_NO_CONNECTION; 789 dccp_v6_ctl_send_reset(sk, skb); 790 } 791 792 discard_it: 793 kfree_skb(skb); 794 return 0; 795 796 discard_and_relse: 797 if (refcounted) 798 sock_put(sk); 799 goto discard_it; 800 } 801 802 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 803 int addr_len) 804 { 805 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 806 struct inet_connection_sock *icsk = inet_csk(sk); 807 struct inet_sock *inet = inet_sk(sk); 808 struct ipv6_pinfo *np = inet6_sk(sk); 809 struct dccp_sock *dp = dccp_sk(sk); 810 struct in6_addr *saddr = NULL, *final_p, final; 811 struct ipv6_txoptions *opt; 812 struct flowi6 fl6; 813 struct dst_entry *dst; 814 int addr_type; 815 int err; 816 817 dp->dccps_role = DCCP_ROLE_CLIENT; 818 819 if (addr_len < SIN6_LEN_RFC2133) 820 return -EINVAL; 821 822 if (usin->sin6_family != AF_INET6) 823 return -EAFNOSUPPORT; 824 825 memset(&fl6, 0, sizeof(fl6)); 826 827 if (np->sndflow) { 828 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 829 IP6_ECN_flow_init(fl6.flowlabel); 830 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 831 struct ip6_flowlabel *flowlabel; 832 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 833 if (IS_ERR(flowlabel)) 834 return -EINVAL; 835 fl6_sock_release(flowlabel); 836 } 837 } 838 /* 839 * connect() to INADDR_ANY means loopback (BSD'ism). 840 */ 841 if (ipv6_addr_any(&usin->sin6_addr)) 842 usin->sin6_addr.s6_addr[15] = 1; 843 844 addr_type = ipv6_addr_type(&usin->sin6_addr); 845 846 if (addr_type & IPV6_ADDR_MULTICAST) 847 return -ENETUNREACH; 848 849 if (addr_type & IPV6_ADDR_LINKLOCAL) { 850 if (addr_len >= sizeof(struct sockaddr_in6) && 851 usin->sin6_scope_id) { 852 /* If interface is set while binding, indices 853 * must coincide. 854 */ 855 if (sk->sk_bound_dev_if && 856 sk->sk_bound_dev_if != usin->sin6_scope_id) 857 return -EINVAL; 858 859 sk->sk_bound_dev_if = usin->sin6_scope_id; 860 } 861 862 /* Connect to link-local address requires an interface */ 863 if (!sk->sk_bound_dev_if) 864 return -EINVAL; 865 } 866 867 sk->sk_v6_daddr = usin->sin6_addr; 868 np->flow_label = fl6.flowlabel; 869 870 /* 871 * DCCP over IPv4 872 */ 873 if (addr_type == IPV6_ADDR_MAPPED) { 874 u32 exthdrlen = icsk->icsk_ext_hdr_len; 875 struct sockaddr_in sin; 876 877 SOCK_DEBUG(sk, "connect: ipv4 mapped\n"); 878 879 if (__ipv6_only_sock(sk)) 880 return -ENETUNREACH; 881 882 sin.sin_family = AF_INET; 883 sin.sin_port = usin->sin6_port; 884 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 885 886 icsk->icsk_af_ops = &dccp_ipv6_mapped; 887 sk->sk_backlog_rcv = dccp_v4_do_rcv; 888 889 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 890 if (err) { 891 icsk->icsk_ext_hdr_len = exthdrlen; 892 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 893 sk->sk_backlog_rcv = dccp_v6_do_rcv; 894 goto failure; 895 } 896 np->saddr = sk->sk_v6_rcv_saddr; 897 return err; 898 } 899 900 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 901 saddr = &sk->sk_v6_rcv_saddr; 902 903 fl6.flowi6_proto = IPPROTO_DCCP; 904 fl6.daddr = sk->sk_v6_daddr; 905 fl6.saddr = saddr ? *saddr : np->saddr; 906 fl6.flowi6_oif = sk->sk_bound_dev_if; 907 fl6.fl6_dport = usin->sin6_port; 908 fl6.fl6_sport = inet->inet_sport; 909 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); 910 911 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 912 final_p = fl6_update_dst(&fl6, opt, &final); 913 914 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 915 if (IS_ERR(dst)) { 916 err = PTR_ERR(dst); 917 goto failure; 918 } 919 920 if (saddr == NULL) { 921 saddr = &fl6.saddr; 922 sk->sk_v6_rcv_saddr = *saddr; 923 } 924 925 /* set the source address */ 926 np->saddr = *saddr; 927 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 928 929 ip6_dst_store(sk, dst, NULL, NULL); 930 931 icsk->icsk_ext_hdr_len = 0; 932 if (opt) 933 icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; 934 935 inet->inet_dport = usin->sin6_port; 936 937 dccp_set_state(sk, DCCP_REQUESTING); 938 err = inet6_hash_connect(&dccp_death_row, sk); 939 if (err) 940 goto late_failure; 941 942 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 943 sk->sk_v6_daddr.s6_addr32, 944 inet->inet_sport, 945 inet->inet_dport); 946 err = dccp_connect(sk); 947 if (err) 948 goto late_failure; 949 950 return 0; 951 952 late_failure: 953 dccp_set_state(sk, DCCP_CLOSED); 954 __sk_dst_reset(sk); 955 failure: 956 inet->inet_dport = 0; 957 sk->sk_route_caps = 0; 958 return err; 959 } 960 961 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 962 .queue_xmit = inet6_csk_xmit, 963 .send_check = dccp_v6_send_check, 964 .rebuild_header = inet6_sk_rebuild_header, 965 .conn_request = dccp_v6_conn_request, 966 .syn_recv_sock = dccp_v6_request_recv_sock, 967 .net_header_len = sizeof(struct ipv6hdr), 968 .setsockopt = ipv6_setsockopt, 969 .getsockopt = ipv6_getsockopt, 970 .addr2sockaddr = inet6_csk_addr2sockaddr, 971 .sockaddr_len = sizeof(struct sockaddr_in6), 972 #ifdef CONFIG_COMPAT 973 .compat_setsockopt = compat_ipv6_setsockopt, 974 .compat_getsockopt = compat_ipv6_getsockopt, 975 #endif 976 }; 977 978 /* 979 * DCCP over IPv4 via INET6 API 980 */ 981 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 982 .queue_xmit = ip_queue_xmit, 983 .send_check = dccp_v4_send_check, 984 .rebuild_header = inet_sk_rebuild_header, 985 .conn_request = dccp_v6_conn_request, 986 .syn_recv_sock = dccp_v6_request_recv_sock, 987 .net_header_len = sizeof(struct iphdr), 988 .setsockopt = ipv6_setsockopt, 989 .getsockopt = ipv6_getsockopt, 990 .addr2sockaddr = inet6_csk_addr2sockaddr, 991 .sockaddr_len = sizeof(struct sockaddr_in6), 992 #ifdef CONFIG_COMPAT 993 .compat_setsockopt = compat_ipv6_setsockopt, 994 .compat_getsockopt = compat_ipv6_getsockopt, 995 #endif 996 }; 997 998 /* NOTE: A lot of things set to zero explicitly by call to 999 * sk_alloc() so need not be done here. 1000 */ 1001 static int dccp_v6_init_sock(struct sock *sk) 1002 { 1003 static __u8 dccp_v6_ctl_sock_initialized; 1004 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 1005 1006 if (err == 0) { 1007 if (unlikely(!dccp_v6_ctl_sock_initialized)) 1008 dccp_v6_ctl_sock_initialized = 1; 1009 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 1010 } 1011 1012 return err; 1013 } 1014 1015 static void dccp_v6_destroy_sock(struct sock *sk) 1016 { 1017 dccp_destroy_sock(sk); 1018 inet6_destroy_sock(sk); 1019 } 1020 1021 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 1022 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 1023 }; 1024 1025 static struct proto dccp_v6_prot = { 1026 .name = "DCCPv6", 1027 .owner = THIS_MODULE, 1028 .close = dccp_close, 1029 .connect = dccp_v6_connect, 1030 .disconnect = dccp_disconnect, 1031 .ioctl = dccp_ioctl, 1032 .init = dccp_v6_init_sock, 1033 .setsockopt = dccp_setsockopt, 1034 .getsockopt = dccp_getsockopt, 1035 .sendmsg = dccp_sendmsg, 1036 .recvmsg = dccp_recvmsg, 1037 .backlog_rcv = dccp_v6_do_rcv, 1038 .hash = inet6_hash, 1039 .unhash = inet_unhash, 1040 .accept = inet_csk_accept, 1041 .get_port = inet_csk_get_port, 1042 .shutdown = dccp_shutdown, 1043 .destroy = dccp_v6_destroy_sock, 1044 .orphan_count = &dccp_orphan_count, 1045 .max_header = MAX_DCCP_HEADER, 1046 .obj_size = sizeof(struct dccp6_sock), 1047 .slab_flags = SLAB_TYPESAFE_BY_RCU, 1048 .rsk_prot = &dccp6_request_sock_ops, 1049 .twsk_prot = &dccp6_timewait_sock_ops, 1050 .h.hashinfo = &dccp_hashinfo, 1051 #ifdef CONFIG_COMPAT 1052 .compat_setsockopt = compat_dccp_setsockopt, 1053 .compat_getsockopt = compat_dccp_getsockopt, 1054 #endif 1055 }; 1056 1057 static const struct inet6_protocol dccp_v6_protocol = { 1058 .handler = dccp_v6_rcv, 1059 .err_handler = dccp_v6_err, 1060 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1061 }; 1062 1063 static const struct proto_ops inet6_dccp_ops = { 1064 .family = PF_INET6, 1065 .owner = THIS_MODULE, 1066 .release = inet6_release, 1067 .bind = inet6_bind, 1068 .connect = inet_stream_connect, 1069 .socketpair = sock_no_socketpair, 1070 .accept = inet_accept, 1071 .getname = inet6_getname, 1072 .poll = dccp_poll, 1073 .ioctl = inet6_ioctl, 1074 .gettstamp = sock_gettstamp, 1075 .listen = inet_dccp_listen, 1076 .shutdown = inet_shutdown, 1077 .setsockopt = sock_common_setsockopt, 1078 .getsockopt = sock_common_getsockopt, 1079 .sendmsg = inet_sendmsg, 1080 .recvmsg = sock_common_recvmsg, 1081 .mmap = sock_no_mmap, 1082 .sendpage = sock_no_sendpage, 1083 #ifdef CONFIG_COMPAT 1084 .compat_setsockopt = compat_sock_common_setsockopt, 1085 .compat_getsockopt = compat_sock_common_getsockopt, 1086 #endif 1087 }; 1088 1089 static struct inet_protosw dccp_v6_protosw = { 1090 .type = SOCK_DCCP, 1091 .protocol = IPPROTO_DCCP, 1092 .prot = &dccp_v6_prot, 1093 .ops = &inet6_dccp_ops, 1094 .flags = INET_PROTOSW_ICSK, 1095 }; 1096 1097 static int __net_init dccp_v6_init_net(struct net *net) 1098 { 1099 if (dccp_hashinfo.bhash == NULL) 1100 return -ESOCKTNOSUPPORT; 1101 1102 return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6, 1103 SOCK_DCCP, IPPROTO_DCCP, net); 1104 } 1105 1106 static void __net_exit dccp_v6_exit_net(struct net *net) 1107 { 1108 inet_ctl_sock_destroy(net->dccp.v6_ctl_sk); 1109 } 1110 1111 static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list) 1112 { 1113 inet_twsk_purge(&dccp_hashinfo, AF_INET6); 1114 } 1115 1116 static struct pernet_operations dccp_v6_ops = { 1117 .init = dccp_v6_init_net, 1118 .exit = dccp_v6_exit_net, 1119 .exit_batch = dccp_v6_exit_batch, 1120 }; 1121 1122 static int __init dccp_v6_init(void) 1123 { 1124 int err = proto_register(&dccp_v6_prot, 1); 1125 1126 if (err) 1127 goto out; 1128 1129 inet6_register_protosw(&dccp_v6_protosw); 1130 1131 err = register_pernet_subsys(&dccp_v6_ops); 1132 if (err) 1133 goto out_destroy_ctl_sock; 1134 1135 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1136 if (err) 1137 goto out_unregister_proto; 1138 1139 out: 1140 return err; 1141 out_unregister_proto: 1142 unregister_pernet_subsys(&dccp_v6_ops); 1143 out_destroy_ctl_sock: 1144 inet6_unregister_protosw(&dccp_v6_protosw); 1145 proto_unregister(&dccp_v6_prot); 1146 goto out; 1147 } 1148 1149 static void __exit dccp_v6_exit(void) 1150 { 1151 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1152 unregister_pernet_subsys(&dccp_v6_ops); 1153 inet6_unregister_protosw(&dccp_v6_protosw); 1154 proto_unregister(&dccp_v6_prot); 1155 } 1156 1157 module_init(dccp_v6_init); 1158 module_exit(dccp_v6_exit); 1159 1160 /* 1161 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) 1162 * values directly, Also cover the case where the protocol is not specified, 1163 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP 1164 */ 1165 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6); 1166 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6); 1167 MODULE_LICENSE("GPL"); 1168 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>"); 1169 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol"); 1170