1 /* 2 * DCCP over IPv6 3 * Linux INET6 implementation 4 * 5 * Based on net/dccp6/ipv6.c 6 * 7 * Arnaldo Carvalho de Melo <[email protected]> 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 */ 14 15 #include <linux/module.h> 16 #include <linux/random.h> 17 #include <linux/slab.h> 18 #include <linux/xfrm.h> 19 20 #include <net/addrconf.h> 21 #include <net/inet_common.h> 22 #include <net/inet_hashtables.h> 23 #include <net/inet_sock.h> 24 #include <net/inet6_connection_sock.h> 25 #include <net/inet6_hashtables.h> 26 #include <net/ip6_route.h> 27 #include <net/ipv6.h> 28 #include <net/protocol.h> 29 #include <net/transp_v6.h> 30 #include <net/ip6_checksum.h> 31 #include <net/xfrm.h> 32 #include <net/secure_seq.h> 33 34 #include "dccp.h" 35 #include "ipv6.h" 36 #include "feat.h" 37 38 /* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */ 39 40 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped; 41 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops; 42 43 /* add pseudo-header to DCCP checksum stored in skb->csum */ 44 static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb, 45 const struct in6_addr *saddr, 46 const struct in6_addr *daddr) 47 { 48 return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum); 49 } 50 51 static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb) 52 { 53 struct ipv6_pinfo *np = inet6_sk(sk); 54 struct dccp_hdr *dh = dccp_hdr(skb); 55 56 dccp_csum_outgoing(skb); 57 dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr); 58 } 59 60 static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb) 61 { 62 return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32, 63 ipv6_hdr(skb)->saddr.s6_addr32, 64 dccp_hdr(skb)->dccph_dport, 65 dccp_hdr(skb)->dccph_sport ); 66 67 } 68 69 static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 70 u8 type, u8 code, int offset, __be32 info) 71 { 72 const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data; 73 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset); 74 struct dccp_sock *dp; 75 struct ipv6_pinfo *np; 76 struct sock *sk; 77 int err; 78 __u64 seq; 79 struct net *net = dev_net(skb->dev); 80 81 if (skb->len < offset + sizeof(*dh) || 82 skb->len < offset + __dccp_basic_hdr_len(dh)) { 83 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev), 84 ICMP6_MIB_INERRORS); 85 return; 86 } 87 88 sk = __inet6_lookup_established(net, &dccp_hashinfo, 89 &hdr->daddr, dh->dccph_dport, 90 &hdr->saddr, ntohs(dh->dccph_sport), 91 inet6_iif(skb)); 92 93 if (!sk) { 94 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev), 95 ICMP6_MIB_INERRORS); 96 return; 97 } 98 99 if (sk->sk_state == DCCP_TIME_WAIT) { 100 inet_twsk_put(inet_twsk(sk)); 101 return; 102 } 103 seq = dccp_hdr_seq(dh); 104 if (sk->sk_state == DCCP_NEW_SYN_RECV) 105 return dccp_req_err(sk, seq); 106 107 bh_lock_sock(sk); 108 if (sock_owned_by_user(sk)) 109 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); 110 111 if (sk->sk_state == DCCP_CLOSED) 112 goto out; 113 114 dp = dccp_sk(sk); 115 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) && 116 !between48(seq, dp->dccps_awl, dp->dccps_awh)) { 117 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); 118 goto out; 119 } 120 121 np = inet6_sk(sk); 122 123 if (type == NDISC_REDIRECT) { 124 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie); 125 126 if (dst) 127 dst->ops->redirect(dst, sk, skb); 128 goto out; 129 } 130 131 if (type == ICMPV6_PKT_TOOBIG) { 132 struct dst_entry *dst = NULL; 133 134 if (!ip6_sk_accept_pmtu(sk)) 135 goto out; 136 137 if (sock_owned_by_user(sk)) 138 goto out; 139 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED)) 140 goto out; 141 142 dst = inet6_csk_update_pmtu(sk, ntohl(info)); 143 if (!dst) 144 goto out; 145 146 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) 147 dccp_sync_mss(sk, dst_mtu(dst)); 148 goto out; 149 } 150 151 icmpv6_err_convert(type, code, &err); 152 153 /* Might be for an request_sock */ 154 switch (sk->sk_state) { 155 case DCCP_REQUESTING: 156 case DCCP_RESPOND: /* Cannot happen. 157 It can, it SYNs are crossed. --ANK */ 158 if (!sock_owned_by_user(sk)) { 159 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS); 160 sk->sk_err = err; 161 /* 162 * Wake people up to see the error 163 * (see connect in sock.c) 164 */ 165 sk->sk_error_report(sk); 166 dccp_done(sk); 167 } else 168 sk->sk_err_soft = err; 169 goto out; 170 } 171 172 if (!sock_owned_by_user(sk) && np->recverr) { 173 sk->sk_err = err; 174 sk->sk_error_report(sk); 175 } else 176 sk->sk_err_soft = err; 177 178 out: 179 bh_unlock_sock(sk); 180 sock_put(sk); 181 } 182 183 184 static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req) 185 { 186 struct inet_request_sock *ireq = inet_rsk(req); 187 struct ipv6_pinfo *np = inet6_sk(sk); 188 struct sk_buff *skb; 189 struct in6_addr *final_p, final; 190 struct flowi6 fl6; 191 int err = -1; 192 struct dst_entry *dst; 193 194 memset(&fl6, 0, sizeof(fl6)); 195 fl6.flowi6_proto = IPPROTO_DCCP; 196 fl6.daddr = ireq->ir_v6_rmt_addr; 197 fl6.saddr = ireq->ir_v6_loc_addr; 198 fl6.flowlabel = 0; 199 fl6.flowi6_oif = ireq->ir_iif; 200 fl6.fl6_dport = ireq->ir_rmt_port; 201 fl6.fl6_sport = htons(ireq->ir_num); 202 security_req_classify_flow(req, flowi6_to_flowi(&fl6)); 203 204 205 final_p = fl6_update_dst(&fl6, np->opt, &final); 206 207 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 208 if (IS_ERR(dst)) { 209 err = PTR_ERR(dst); 210 dst = NULL; 211 goto done; 212 } 213 214 skb = dccp_make_response(sk, dst, req); 215 if (skb != NULL) { 216 struct dccp_hdr *dh = dccp_hdr(skb); 217 218 dh->dccph_checksum = dccp_v6_csum_finish(skb, 219 &ireq->ir_v6_loc_addr, 220 &ireq->ir_v6_rmt_addr); 221 fl6.daddr = ireq->ir_v6_rmt_addr; 222 err = ip6_xmit(sk, skb, &fl6, np->opt, np->tclass); 223 err = net_xmit_eval(err); 224 } 225 226 done: 227 dst_release(dst); 228 return err; 229 } 230 231 static void dccp_v6_reqsk_destructor(struct request_sock *req) 232 { 233 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); 234 kfree_skb(inet_rsk(req)->pktopts); 235 } 236 237 static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) 238 { 239 const struct ipv6hdr *rxip6h; 240 struct sk_buff *skb; 241 struct flowi6 fl6; 242 struct net *net = dev_net(skb_dst(rxskb)->dev); 243 struct sock *ctl_sk = net->dccp.v6_ctl_sk; 244 struct dst_entry *dst; 245 246 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) 247 return; 248 249 if (!ipv6_unicast_destination(rxskb)) 250 return; 251 252 skb = dccp_ctl_make_reset(ctl_sk, rxskb); 253 if (skb == NULL) 254 return; 255 256 rxip6h = ipv6_hdr(rxskb); 257 dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr, 258 &rxip6h->daddr); 259 260 memset(&fl6, 0, sizeof(fl6)); 261 fl6.daddr = rxip6h->saddr; 262 fl6.saddr = rxip6h->daddr; 263 264 fl6.flowi6_proto = IPPROTO_DCCP; 265 fl6.flowi6_oif = inet6_iif(rxskb); 266 fl6.fl6_dport = dccp_hdr(skb)->dccph_dport; 267 fl6.fl6_sport = dccp_hdr(skb)->dccph_sport; 268 security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6)); 269 270 /* sk = NULL, but it is safe for now. RST socket required. */ 271 dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL); 272 if (!IS_ERR(dst)) { 273 skb_dst_set(skb, dst); 274 ip6_xmit(ctl_sk, skb, &fl6, NULL, 0); 275 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS); 276 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS); 277 return; 278 } 279 280 kfree_skb(skb); 281 } 282 283 static struct request_sock_ops dccp6_request_sock_ops = { 284 .family = AF_INET6, 285 .obj_size = sizeof(struct dccp6_request_sock), 286 .rtx_syn_ack = dccp_v6_send_response, 287 .send_ack = dccp_reqsk_send_ack, 288 .destructor = dccp_v6_reqsk_destructor, 289 .send_reset = dccp_v6_ctl_send_reset, 290 .syn_ack_timeout = dccp_syn_ack_timeout, 291 }; 292 293 static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 294 { 295 struct request_sock *req; 296 struct dccp_request_sock *dreq; 297 struct inet_request_sock *ireq; 298 struct ipv6_pinfo *np = inet6_sk(sk); 299 const __be32 service = dccp_hdr_request(skb)->dccph_req_service; 300 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); 301 302 if (skb->protocol == htons(ETH_P_IP)) 303 return dccp_v4_conn_request(sk, skb); 304 305 if (!ipv6_unicast_destination(skb)) 306 return 0; /* discard, don't send a reset here */ 307 308 if (dccp_bad_service_code(sk, service)) { 309 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE; 310 goto drop; 311 } 312 /* 313 * There are no SYN attacks on IPv6, yet... 314 */ 315 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 316 if (inet_csk_reqsk_queue_is_full(sk)) 317 goto drop; 318 319 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) 320 goto drop; 321 322 req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true); 323 if (req == NULL) 324 goto drop; 325 326 if (dccp_reqsk_init(req, dccp_sk(sk), skb)) 327 goto drop_and_free; 328 329 dreq = dccp_rsk(req); 330 if (dccp_parse_options(sk, dreq, skb)) 331 goto drop_and_free; 332 333 if (security_inet_conn_request(sk, skb, req)) 334 goto drop_and_free; 335 336 ireq = inet_rsk(req); 337 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; 338 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; 339 ireq->ireq_family = AF_INET6; 340 341 if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) || 342 np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || 343 np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { 344 atomic_inc(&skb->users); 345 ireq->pktopts = skb; 346 } 347 ireq->ir_iif = sk->sk_bound_dev_if; 348 349 /* So that link locals have meaning */ 350 if (!sk->sk_bound_dev_if && 351 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 352 ireq->ir_iif = inet6_iif(skb); 353 354 /* 355 * Step 3: Process LISTEN state 356 * 357 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie 358 * 359 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child(). 360 */ 361 dreq->dreq_isr = dcb->dccpd_seq; 362 dreq->dreq_gsr = dreq->dreq_isr; 363 dreq->dreq_iss = dccp_v6_init_sequence(skb); 364 dreq->dreq_gss = dreq->dreq_iss; 365 dreq->dreq_service = service; 366 367 if (dccp_v6_send_response(sk, req)) 368 goto drop_and_free; 369 370 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); 371 return 0; 372 373 drop_and_free: 374 reqsk_free(req); 375 drop: 376 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS); 377 return -1; 378 } 379 380 static struct sock *dccp_v6_request_recv_sock(const struct sock *sk, 381 struct sk_buff *skb, 382 struct request_sock *req, 383 struct dst_entry *dst, 384 struct request_sock *req_unhash, 385 bool *own_req) 386 { 387 struct inet_request_sock *ireq = inet_rsk(req); 388 struct ipv6_pinfo *newnp; 389 const struct ipv6_pinfo *np = inet6_sk(sk); 390 struct inet_sock *newinet; 391 struct dccp6_sock *newdp6; 392 struct sock *newsk; 393 394 if (skb->protocol == htons(ETH_P_IP)) { 395 /* 396 * v6 mapped 397 */ 398 newsk = dccp_v4_request_recv_sock(sk, skb, req, dst, 399 req_unhash, own_req); 400 if (newsk == NULL) 401 return NULL; 402 403 newdp6 = (struct dccp6_sock *)newsk; 404 newinet = inet_sk(newsk); 405 newinet->pinet6 = &newdp6->inet6; 406 newnp = inet6_sk(newsk); 407 408 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 409 410 newnp->saddr = newsk->sk_v6_rcv_saddr; 411 412 inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped; 413 newsk->sk_backlog_rcv = dccp_v4_do_rcv; 414 newnp->pktoptions = NULL; 415 newnp->opt = NULL; 416 newnp->mcast_oif = inet6_iif(skb); 417 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 418 419 /* 420 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 421 * here, dccp_create_openreq_child now does this for us, see the comment in 422 * that function for the gory details. -acme 423 */ 424 425 /* It is tricky place. Until this moment IPv4 tcp 426 worked with IPv6 icsk.icsk_af_ops. 427 Sync it now. 428 */ 429 dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 430 431 return newsk; 432 } 433 434 435 if (sk_acceptq_is_full(sk)) 436 goto out_overflow; 437 438 if (!dst) { 439 struct flowi6 fl6; 440 441 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP); 442 if (!dst) 443 goto out; 444 } 445 446 newsk = dccp_create_openreq_child(sk, req, skb); 447 if (newsk == NULL) 448 goto out_nonewsk; 449 450 /* 451 * No need to charge this sock to the relevant IPv6 refcnt debug socks 452 * count here, dccp_create_openreq_child now does this for us, see the 453 * comment in that function for the gory details. -acme 454 */ 455 456 __ip6_dst_store(newsk, dst, NULL, NULL); 457 newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM | 458 NETIF_F_TSO); 459 newdp6 = (struct dccp6_sock *)newsk; 460 newinet = inet_sk(newsk); 461 newinet->pinet6 = &newdp6->inet6; 462 newnp = inet6_sk(newsk); 463 464 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 465 466 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 467 newnp->saddr = ireq->ir_v6_loc_addr; 468 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 469 newsk->sk_bound_dev_if = ireq->ir_iif; 470 471 /* Now IPv6 options... 472 473 First: no IPv4 options. 474 */ 475 newinet->inet_opt = NULL; 476 477 /* Clone RX bits */ 478 newnp->rxopt.all = np->rxopt.all; 479 480 newnp->pktoptions = NULL; 481 newnp->opt = NULL; 482 newnp->mcast_oif = inet6_iif(skb); 483 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 484 485 /* 486 * Clone native IPv6 options from listening socket (if any) 487 * 488 * Yes, keeping reference count would be much more clever, but we make 489 * one more one thing there: reattach optmem to newsk. 490 */ 491 if (np->opt != NULL) 492 newnp->opt = ipv6_dup_options(newsk, np->opt); 493 494 inet_csk(newsk)->icsk_ext_hdr_len = 0; 495 if (newnp->opt != NULL) 496 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen + 497 newnp->opt->opt_flen); 498 499 dccp_sync_mss(newsk, dst_mtu(dst)); 500 501 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 502 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 503 504 if (__inet_inherit_port(sk, newsk) < 0) { 505 inet_csk_prepare_forced_close(newsk); 506 dccp_done(newsk); 507 goto out; 508 } 509 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); 510 /* Clone pktoptions received with SYN, if we own the req */ 511 if (*own_req && ireq->pktopts) { 512 newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC); 513 consume_skb(ireq->pktopts); 514 ireq->pktopts = NULL; 515 if (newnp->pktoptions) 516 skb_set_owner_r(newnp->pktoptions, newsk); 517 } 518 519 return newsk; 520 521 out_overflow: 522 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 523 out_nonewsk: 524 dst_release(dst); 525 out: 526 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); 527 return NULL; 528 } 529 530 /* The socket must have it's spinlock held when we get 531 * here. 532 * 533 * We have a potential double-lock case here, so even when 534 * doing backlog processing we use the BH locking scheme. 535 * This is because we cannot sleep with the original spinlock 536 * held. 537 */ 538 static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 539 { 540 struct ipv6_pinfo *np = inet6_sk(sk); 541 struct sk_buff *opt_skb = NULL; 542 543 /* Imagine: socket is IPv6. IPv4 packet arrives, 544 goes to IPv4 receive handler and backlogged. 545 From backlog it always goes here. Kerboom... 546 Fortunately, dccp_rcv_established and rcv_established 547 handle them correctly, but it is not case with 548 dccp_v6_hnd_req and dccp_v6_ctl_send_reset(). --ANK 549 */ 550 551 if (skb->protocol == htons(ETH_P_IP)) 552 return dccp_v4_do_rcv(sk, skb); 553 554 if (sk_filter(sk, skb)) 555 goto discard; 556 557 /* 558 * socket locking is here for SMP purposes as backlog rcv is currently 559 * called with bh processing disabled. 560 */ 561 562 /* Do Stevens' IPV6_PKTOPTIONS. 563 564 Yes, guys, it is the only place in our code, where we 565 may make it not affecting IPv4. 566 The rest of code is protocol independent, 567 and I do not like idea to uglify IPv4. 568 569 Actually, all the idea behind IPV6_PKTOPTIONS 570 looks not very well thought. For now we latch 571 options, received in the last packet, enqueued 572 by tcp. Feel free to propose better solution. 573 --ANK (980728) 574 */ 575 if (np->rxopt.all) 576 /* 577 * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below 578 * (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example. 579 */ 580 opt_skb = skb_clone(skb, GFP_ATOMIC); 581 582 if (sk->sk_state == DCCP_OPEN) { /* Fast path */ 583 if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len)) 584 goto reset; 585 if (opt_skb) { 586 /* XXX This is where we would goto ipv6_pktoptions. */ 587 __kfree_skb(opt_skb); 588 } 589 return 0; 590 } 591 592 /* 593 * Step 3: Process LISTEN state 594 * If S.state == LISTEN, 595 * If P.type == Request or P contains a valid Init Cookie option, 596 * (* Must scan the packet's options to check for Init 597 * Cookies. Only Init Cookies are processed here, 598 * however; other options are processed in Step 8. This 599 * scan need only be performed if the endpoint uses Init 600 * Cookies *) 601 * (* Generate a new socket and switch to that socket *) 602 * Set S := new socket for this port pair 603 * S.state = RESPOND 604 * Choose S.ISS (initial seqno) or set from Init Cookies 605 * Initialize S.GAR := S.ISS 606 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 607 * Continue with S.state == RESPOND 608 * (* A Response packet will be generated in Step 11 *) 609 * Otherwise, 610 * Generate Reset(No Connection) unless P.type == Reset 611 * Drop packet and return 612 * 613 * NOTE: the check for the packet types is done in 614 * dccp_rcv_state_process 615 */ 616 617 if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len)) 618 goto reset; 619 if (opt_skb) { 620 /* XXX This is where we would goto ipv6_pktoptions. */ 621 __kfree_skb(opt_skb); 622 } 623 return 0; 624 625 reset: 626 dccp_v6_ctl_send_reset(sk, skb); 627 discard: 628 if (opt_skb != NULL) 629 __kfree_skb(opt_skb); 630 kfree_skb(skb); 631 return 0; 632 } 633 634 static int dccp_v6_rcv(struct sk_buff *skb) 635 { 636 const struct dccp_hdr *dh; 637 struct sock *sk; 638 int min_cov; 639 640 /* Step 1: Check header basics */ 641 642 if (dccp_invalid_packet(skb)) 643 goto discard_it; 644 645 /* Step 1: If header checksum is incorrect, drop packet and return. */ 646 if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, 647 &ipv6_hdr(skb)->daddr)) { 648 DCCP_WARN("dropped packet with invalid checksum\n"); 649 goto discard_it; 650 } 651 652 dh = dccp_hdr(skb); 653 654 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); 655 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; 656 657 if (dccp_packet_without_ack(skb)) 658 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; 659 else 660 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); 661 662 lookup: 663 sk = __inet6_lookup_skb(&dccp_hashinfo, skb, 664 dh->dccph_sport, dh->dccph_dport, 665 inet6_iif(skb)); 666 if (!sk) { 667 dccp_pr_debug("failed to look up flow ID in table and " 668 "get corresponding socket\n"); 669 goto no_dccp_socket; 670 } 671 672 /* 673 * Step 2: 674 * ... or S.state == TIMEWAIT, 675 * Generate Reset(No Connection) unless P.type == Reset 676 * Drop packet and return 677 */ 678 if (sk->sk_state == DCCP_TIME_WAIT) { 679 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); 680 inet_twsk_put(inet_twsk(sk)); 681 goto no_dccp_socket; 682 } 683 684 if (sk->sk_state == DCCP_NEW_SYN_RECV) { 685 struct request_sock *req = inet_reqsk(sk); 686 struct sock *nsk = NULL; 687 688 sk = req->rsk_listener; 689 if (likely(sk->sk_state == DCCP_LISTEN)) { 690 nsk = dccp_check_req(sk, skb, req); 691 } else { 692 inet_csk_reqsk_queue_drop_and_put(sk, req); 693 goto lookup; 694 } 695 if (!nsk) { 696 reqsk_put(req); 697 goto discard_it; 698 } 699 if (nsk == sk) { 700 sock_hold(sk); 701 reqsk_put(req); 702 } else if (dccp_child_process(sk, nsk, skb)) { 703 dccp_v6_ctl_send_reset(sk, skb); 704 goto discard_it; 705 } else { 706 return 0; 707 } 708 } 709 /* 710 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage 711 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted 712 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov 713 */ 714 min_cov = dccp_sk(sk)->dccps_pcrlen; 715 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { 716 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", 717 dh->dccph_cscov, min_cov); 718 /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ 719 goto discard_and_relse; 720 } 721 722 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 723 goto discard_and_relse; 724 725 return sk_receive_skb(sk, skb, 1) ? -1 : 0; 726 727 no_dccp_socket: 728 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 729 goto discard_it; 730 /* 731 * Step 2: 732 * If no socket ... 733 * Generate Reset(No Connection) unless P.type == Reset 734 * Drop packet and return 735 */ 736 if (dh->dccph_type != DCCP_PKT_RESET) { 737 DCCP_SKB_CB(skb)->dccpd_reset_code = 738 DCCP_RESET_CODE_NO_CONNECTION; 739 dccp_v6_ctl_send_reset(sk, skb); 740 } 741 742 discard_it: 743 kfree_skb(skb); 744 return 0; 745 746 discard_and_relse: 747 sock_put(sk); 748 goto discard_it; 749 } 750 751 static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 752 int addr_len) 753 { 754 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 755 struct inet_connection_sock *icsk = inet_csk(sk); 756 struct inet_sock *inet = inet_sk(sk); 757 struct ipv6_pinfo *np = inet6_sk(sk); 758 struct dccp_sock *dp = dccp_sk(sk); 759 struct in6_addr *saddr = NULL, *final_p, final; 760 struct flowi6 fl6; 761 struct dst_entry *dst; 762 int addr_type; 763 int err; 764 765 dp->dccps_role = DCCP_ROLE_CLIENT; 766 767 if (addr_len < SIN6_LEN_RFC2133) 768 return -EINVAL; 769 770 if (usin->sin6_family != AF_INET6) 771 return -EAFNOSUPPORT; 772 773 memset(&fl6, 0, sizeof(fl6)); 774 775 if (np->sndflow) { 776 fl6.flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 777 IP6_ECN_flow_init(fl6.flowlabel); 778 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 779 struct ip6_flowlabel *flowlabel; 780 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 781 if (flowlabel == NULL) 782 return -EINVAL; 783 fl6_sock_release(flowlabel); 784 } 785 } 786 /* 787 * connect() to INADDR_ANY means loopback (BSD'ism). 788 */ 789 if (ipv6_addr_any(&usin->sin6_addr)) 790 usin->sin6_addr.s6_addr[15] = 1; 791 792 addr_type = ipv6_addr_type(&usin->sin6_addr); 793 794 if (addr_type & IPV6_ADDR_MULTICAST) 795 return -ENETUNREACH; 796 797 if (addr_type & IPV6_ADDR_LINKLOCAL) { 798 if (addr_len >= sizeof(struct sockaddr_in6) && 799 usin->sin6_scope_id) { 800 /* If interface is set while binding, indices 801 * must coincide. 802 */ 803 if (sk->sk_bound_dev_if && 804 sk->sk_bound_dev_if != usin->sin6_scope_id) 805 return -EINVAL; 806 807 sk->sk_bound_dev_if = usin->sin6_scope_id; 808 } 809 810 /* Connect to link-local address requires an interface */ 811 if (!sk->sk_bound_dev_if) 812 return -EINVAL; 813 } 814 815 sk->sk_v6_daddr = usin->sin6_addr; 816 np->flow_label = fl6.flowlabel; 817 818 /* 819 * DCCP over IPv4 820 */ 821 if (addr_type == IPV6_ADDR_MAPPED) { 822 u32 exthdrlen = icsk->icsk_ext_hdr_len; 823 struct sockaddr_in sin; 824 825 SOCK_DEBUG(sk, "connect: ipv4 mapped\n"); 826 827 if (__ipv6_only_sock(sk)) 828 return -ENETUNREACH; 829 830 sin.sin_family = AF_INET; 831 sin.sin_port = usin->sin6_port; 832 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 833 834 icsk->icsk_af_ops = &dccp_ipv6_mapped; 835 sk->sk_backlog_rcv = dccp_v4_do_rcv; 836 837 err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 838 if (err) { 839 icsk->icsk_ext_hdr_len = exthdrlen; 840 icsk->icsk_af_ops = &dccp_ipv6_af_ops; 841 sk->sk_backlog_rcv = dccp_v6_do_rcv; 842 goto failure; 843 } 844 np->saddr = sk->sk_v6_rcv_saddr; 845 return err; 846 } 847 848 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 849 saddr = &sk->sk_v6_rcv_saddr; 850 851 fl6.flowi6_proto = IPPROTO_DCCP; 852 fl6.daddr = sk->sk_v6_daddr; 853 fl6.saddr = saddr ? *saddr : np->saddr; 854 fl6.flowi6_oif = sk->sk_bound_dev_if; 855 fl6.fl6_dport = usin->sin6_port; 856 fl6.fl6_sport = inet->inet_sport; 857 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); 858 859 final_p = fl6_update_dst(&fl6, np->opt, &final); 860 861 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 862 if (IS_ERR(dst)) { 863 err = PTR_ERR(dst); 864 goto failure; 865 } 866 867 if (saddr == NULL) { 868 saddr = &fl6.saddr; 869 sk->sk_v6_rcv_saddr = *saddr; 870 } 871 872 /* set the source address */ 873 np->saddr = *saddr; 874 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 875 876 __ip6_dst_store(sk, dst, NULL, NULL); 877 878 icsk->icsk_ext_hdr_len = 0; 879 if (np->opt != NULL) 880 icsk->icsk_ext_hdr_len = (np->opt->opt_flen + 881 np->opt->opt_nflen); 882 883 inet->inet_dport = usin->sin6_port; 884 885 dccp_set_state(sk, DCCP_REQUESTING); 886 err = inet6_hash_connect(&dccp_death_row, sk); 887 if (err) 888 goto late_failure; 889 890 dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32, 891 sk->sk_v6_daddr.s6_addr32, 892 inet->inet_sport, 893 inet->inet_dport); 894 err = dccp_connect(sk); 895 if (err) 896 goto late_failure; 897 898 return 0; 899 900 late_failure: 901 dccp_set_state(sk, DCCP_CLOSED); 902 __sk_dst_reset(sk); 903 failure: 904 inet->inet_dport = 0; 905 sk->sk_route_caps = 0; 906 return err; 907 } 908 909 static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops = { 910 .queue_xmit = inet6_csk_xmit, 911 .send_check = dccp_v6_send_check, 912 .rebuild_header = inet6_sk_rebuild_header, 913 .conn_request = dccp_v6_conn_request, 914 .syn_recv_sock = dccp_v6_request_recv_sock, 915 .net_header_len = sizeof(struct ipv6hdr), 916 .setsockopt = ipv6_setsockopt, 917 .getsockopt = ipv6_getsockopt, 918 .addr2sockaddr = inet6_csk_addr2sockaddr, 919 .sockaddr_len = sizeof(struct sockaddr_in6), 920 .bind_conflict = inet6_csk_bind_conflict, 921 #ifdef CONFIG_COMPAT 922 .compat_setsockopt = compat_ipv6_setsockopt, 923 .compat_getsockopt = compat_ipv6_getsockopt, 924 #endif 925 }; 926 927 /* 928 * DCCP over IPv4 via INET6 API 929 */ 930 static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = { 931 .queue_xmit = ip_queue_xmit, 932 .send_check = dccp_v4_send_check, 933 .rebuild_header = inet_sk_rebuild_header, 934 .conn_request = dccp_v6_conn_request, 935 .syn_recv_sock = dccp_v6_request_recv_sock, 936 .net_header_len = sizeof(struct iphdr), 937 .setsockopt = ipv6_setsockopt, 938 .getsockopt = ipv6_getsockopt, 939 .addr2sockaddr = inet6_csk_addr2sockaddr, 940 .sockaddr_len = sizeof(struct sockaddr_in6), 941 #ifdef CONFIG_COMPAT 942 .compat_setsockopt = compat_ipv6_setsockopt, 943 .compat_getsockopt = compat_ipv6_getsockopt, 944 #endif 945 }; 946 947 /* NOTE: A lot of things set to zero explicitly by call to 948 * sk_alloc() so need not be done here. 949 */ 950 static int dccp_v6_init_sock(struct sock *sk) 951 { 952 static __u8 dccp_v6_ctl_sock_initialized; 953 int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized); 954 955 if (err == 0) { 956 if (unlikely(!dccp_v6_ctl_sock_initialized)) 957 dccp_v6_ctl_sock_initialized = 1; 958 inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops; 959 } 960 961 return err; 962 } 963 964 static void dccp_v6_destroy_sock(struct sock *sk) 965 { 966 dccp_destroy_sock(sk); 967 inet6_destroy_sock(sk); 968 } 969 970 static struct timewait_sock_ops dccp6_timewait_sock_ops = { 971 .twsk_obj_size = sizeof(struct dccp6_timewait_sock), 972 }; 973 974 static struct proto dccp_v6_prot = { 975 .name = "DCCPv6", 976 .owner = THIS_MODULE, 977 .close = dccp_close, 978 .connect = dccp_v6_connect, 979 .disconnect = dccp_disconnect, 980 .ioctl = dccp_ioctl, 981 .init = dccp_v6_init_sock, 982 .setsockopt = dccp_setsockopt, 983 .getsockopt = dccp_getsockopt, 984 .sendmsg = dccp_sendmsg, 985 .recvmsg = dccp_recvmsg, 986 .backlog_rcv = dccp_v6_do_rcv, 987 .hash = inet_hash, 988 .unhash = inet_unhash, 989 .accept = inet_csk_accept, 990 .get_port = inet_csk_get_port, 991 .shutdown = dccp_shutdown, 992 .destroy = dccp_v6_destroy_sock, 993 .orphan_count = &dccp_orphan_count, 994 .max_header = MAX_DCCP_HEADER, 995 .obj_size = sizeof(struct dccp6_sock), 996 .slab_flags = SLAB_DESTROY_BY_RCU, 997 .rsk_prot = &dccp6_request_sock_ops, 998 .twsk_prot = &dccp6_timewait_sock_ops, 999 .h.hashinfo = &dccp_hashinfo, 1000 #ifdef CONFIG_COMPAT 1001 .compat_setsockopt = compat_dccp_setsockopt, 1002 .compat_getsockopt = compat_dccp_getsockopt, 1003 #endif 1004 }; 1005 1006 static const struct inet6_protocol dccp_v6_protocol = { 1007 .handler = dccp_v6_rcv, 1008 .err_handler = dccp_v6_err, 1009 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL, 1010 }; 1011 1012 static const struct proto_ops inet6_dccp_ops = { 1013 .family = PF_INET6, 1014 .owner = THIS_MODULE, 1015 .release = inet6_release, 1016 .bind = inet6_bind, 1017 .connect = inet_stream_connect, 1018 .socketpair = sock_no_socketpair, 1019 .accept = inet_accept, 1020 .getname = inet6_getname, 1021 .poll = dccp_poll, 1022 .ioctl = inet6_ioctl, 1023 .listen = inet_dccp_listen, 1024 .shutdown = inet_shutdown, 1025 .setsockopt = sock_common_setsockopt, 1026 .getsockopt = sock_common_getsockopt, 1027 .sendmsg = inet_sendmsg, 1028 .recvmsg = sock_common_recvmsg, 1029 .mmap = sock_no_mmap, 1030 .sendpage = sock_no_sendpage, 1031 #ifdef CONFIG_COMPAT 1032 .compat_setsockopt = compat_sock_common_setsockopt, 1033 .compat_getsockopt = compat_sock_common_getsockopt, 1034 #endif 1035 }; 1036 1037 static struct inet_protosw dccp_v6_protosw = { 1038 .type = SOCK_DCCP, 1039 .protocol = IPPROTO_DCCP, 1040 .prot = &dccp_v6_prot, 1041 .ops = &inet6_dccp_ops, 1042 .flags = INET_PROTOSW_ICSK, 1043 }; 1044 1045 static int __net_init dccp_v6_init_net(struct net *net) 1046 { 1047 if (dccp_hashinfo.bhash == NULL) 1048 return -ESOCKTNOSUPPORT; 1049 1050 return inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6, 1051 SOCK_DCCP, IPPROTO_DCCP, net); 1052 } 1053 1054 static void __net_exit dccp_v6_exit_net(struct net *net) 1055 { 1056 inet_ctl_sock_destroy(net->dccp.v6_ctl_sk); 1057 } 1058 1059 static struct pernet_operations dccp_v6_ops = { 1060 .init = dccp_v6_init_net, 1061 .exit = dccp_v6_exit_net, 1062 }; 1063 1064 static int __init dccp_v6_init(void) 1065 { 1066 int err = proto_register(&dccp_v6_prot, 1); 1067 1068 if (err != 0) 1069 goto out; 1070 1071 err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1072 if (err != 0) 1073 goto out_unregister_proto; 1074 1075 inet6_register_protosw(&dccp_v6_protosw); 1076 1077 err = register_pernet_subsys(&dccp_v6_ops); 1078 if (err != 0) 1079 goto out_destroy_ctl_sock; 1080 out: 1081 return err; 1082 1083 out_destroy_ctl_sock: 1084 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1085 inet6_unregister_protosw(&dccp_v6_protosw); 1086 out_unregister_proto: 1087 proto_unregister(&dccp_v6_prot); 1088 goto out; 1089 } 1090 1091 static void __exit dccp_v6_exit(void) 1092 { 1093 unregister_pernet_subsys(&dccp_v6_ops); 1094 inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP); 1095 inet6_unregister_protosw(&dccp_v6_protosw); 1096 proto_unregister(&dccp_v6_prot); 1097 } 1098 1099 module_init(dccp_v6_init); 1100 module_exit(dccp_v6_exit); 1101 1102 /* 1103 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33) 1104 * values directly, Also cover the case where the protocol is not specified, 1105 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP 1106 */ 1107 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6); 1108 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6); 1109 MODULE_LICENSE("GPL"); 1110 MODULE_AUTHOR("Arnaldo Carvalho de Melo <[email protected]>"); 1111 MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol"); 1112