1 /* $KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright (C) 2000 WIDE Project. 7 * Copyright (c) 2010 Hiroki Sato <hrs@FreeBSD.org> 8 * Copyright (c) 2013 Ermal Luci <eri@FreeBSD.org> 9 * Copyright (c) 2017-2021 Rubicon Communications, LLC (Netgate) 10 * All rights reserved. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the project nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 /* 38 * 6to4 interface, based on RFC3056. 39 * 40 * 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting. 41 * There is no address mapping defined from IPv6 multicast address to IPv4 42 * address. Therefore, we do not have IFF_MULTICAST on the interface. 43 * 44 * Due to the lack of address mapping for link-local addresses, we cannot 45 * throw packets toward link-local addresses (fe80::x). Also, we cannot throw 46 * packets to link-local multicast addresses (ff02::x). 47 * 48 * Here are interesting symptoms due to the lack of link-local address: 49 * 50 * Unicast routing exchange: 51 * - RIPng: Impossible. Uses link-local multicast packet toward ff02::9, 52 * and link-local addresses as nexthop. 53 * - OSPFv6: Impossible. OSPFv6 assumes that there's link-local address 54 * assigned to the link, and makes use of them. Also, HELLO packets use 55 * link-local multicast addresses (ff02::5 and ff02::6). 56 * - BGP4+: Maybe. You can only use global address as nexthop, and global 57 * address as TCP endpoint address. 58 * 59 * Multicast routing protocols: 60 * - PIM: Hello packet cannot be used to discover adjacent PIM routers. 61 * Adjacent PIM routers must be configured manually (is it really spec-wise 62 * correct thing to do?). 63 * 64 * ICMPv6: 65 * - Redirects cannot be used due to the lack of link-local address. 66 * 67 * stf interface does not have, and will not need, a link-local address. 68 * It seems to have no real benefit and does not help the above symptoms much. 69 * Even if we assign link-locals to interface, we cannot really 70 * use link-local unicast/multicast on top of 6to4 cloud (since there's no 71 * encapsulation defined for link-local address), and the above analysis does 72 * not change. RFC3056 does not mandate the assignment of link-local address 73 * either. 74 * 75 * 6to4 interface has security issues. Refer to 76 * http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt 77 * for details. The code tries to filter out some of malicious packets. 78 * Note that there is no way to be 100% secure. 79 */ 80 81 #include <sys/param.h> 82 #include <sys/systm.h> 83 #include <sys/socket.h> 84 #include <sys/sockio.h> 85 #include <sys/mbuf.h> 86 #include <sys/endian.h> 87 #include <sys/errno.h> 88 #include <sys/kernel.h> 89 #include <sys/lock.h> 90 #include <sys/module.h> 91 #include <sys/priv.h> 92 #include <sys/proc.h> 93 #include <sys/queue.h> 94 #include <sys/sdt.h> 95 #include <sys/sysctl.h> 96 #include <machine/cpu.h> 97 98 #include <sys/malloc.h> 99 100 #include <net/if.h> 101 #include <net/if_var.h> 102 #include <net/if_private.h> 103 #include <net/if_clone.h> 104 #include <net/route.h> 105 #include <net/route/nhop.h> 106 #include <net/netisr.h> 107 #include <net/if_stf.h> 108 #include <net/if_types.h> 109 #include <net/vnet.h> 110 111 #include <netinet/in.h> 112 #include <netinet/in_fib.h> 113 #include <netinet/in_systm.h> 114 #include <netinet/ip.h> 115 #include <netinet/ip_var.h> 116 #include <netinet/in_var.h> 117 118 #include <netinet/ip6.h> 119 #include <netinet6/in6_fib.h> 120 #include <netinet6/ip6_var.h> 121 #include <netinet6/in6_var.h> 122 #include <netinet/ip_ecn.h> 123 124 #include <netinet/ip_encap.h> 125 126 #include <machine/stdarg.h> 127 128 #include <net/bpf.h> 129 130 #include <security/mac/mac_framework.h> 131 132 SDT_PROVIDER_DEFINE(if_stf); 133 SDT_PROBE_DEFINE3(if_stf, , encapcheck, in, "struct mbuf *", "int", "int"); 134 SDT_PROBE_DEFINE0(if_stf, , encapcheck, accept); 135 SDT_PROBE_DEFINE3(if_stf, , getsrcifa6, in, "struct ifnet *", 136 "struct in6_addr *", "struct in6_addr *"); 137 SDT_PROBE_DEFINE2(if_stf, , getsrcifa6, found, "struct in6_addr *", 138 "struct in6_addr *"); 139 SDT_PROBE_DEFINE0(if_stf, , getsrcifa6, notfound); 140 141 SDT_PROBE_DEFINE4(if_stf, , stf_output, in, "struct ifnet *", "struct mbuf *", 142 "struct sockaddr *", "struct route *"); 143 SDT_PROBE_DEFINE2(if_stf, , stf_output, error, "int", "int"); 144 SDT_PROBE_DEFINE1(if_stf, , stf_output, out, "int"); 145 146 SDT_PROBE_DEFINE3(if_stf, , checkaddr6, in, "struct stf_softc *", 147 "struct in6_addr *", "struct ifnet *"); 148 SDT_PROBE_DEFINE2(if_stf, , checkaddr6, out, "int", "int"); 149 150 SDT_PROBE_DEFINE3(if_stf, , stf_input, in, "struct mbuf *", "int", "int"); 151 SDT_PROBE_DEFINE2(if_stf, , stf_input, out, "int", "int"); 152 153 SDT_PROBE_DEFINE3(if_stf, , ioctl, sv4net, "struct in_addr *", 154 "struct in_addr *", "int"); 155 SDT_PROBE_DEFINE1(if_stf, , ioctl, sdstv4, "struct in_addr *"); 156 SDT_PROBE_DEFINE1(if_stf, , ioctl, ifaddr, "struct ifaddr *"); 157 158 SDT_PROBE_DEFINE4(if_stf, , getin4addr_in6, out, "struct in6_addr *", 159 "struct in6_addr *", "struct in6_addr *", "struct sockaddr_in *"); 160 161 SDT_PROBE_DEFINE2(if_stf, , getin4addr, in, "struct in6_addr *", "struct in6_addr *"); 162 SDT_PROBE_DEFINE1(if_stf, , getin4addr, out, "struct sockaddr_in *"); 163 164 SYSCTL_DECL(_net_link); 165 static SYSCTL_NODE(_net_link, IFT_STF, stf, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 166 "6to4 Interface"); 167 168 static int stf_permit_rfc1918 = 0; 169 SYSCTL_INT(_net_link_stf, OID_AUTO, permit_rfc1918, CTLFLAG_RWTUN, 170 &stf_permit_rfc1918, 0, "Permit the use of private IPv4 addresses"); 171 172 #define STFUNIT 0 173 174 #define IN6_IS_ADDR_6TO4(x) (ntohs((x)->s6_addr16[0]) == 0x2002) 175 176 /* 177 * XXX: Return a pointer with 16-bit aligned. Don't cast it to 178 * struct in_addr *; use bcopy() instead. 179 */ 180 #define GET_V4(x) (&(x)->s6_addr16[1]) 181 182 struct stf_softc { 183 struct ifnet *sc_ifp; 184 in_addr_t braddr; /* Border relay IPv4 address */ 185 in_addr_t srcv4_addr; /* Our IPv4 WAN address */ 186 u_int v4prefixlen; /* How much of the v4 address to include in our address. */ 187 u_int sc_fibnum; 188 const struct encaptab *encap_cookie; 189 }; 190 #define STF2IFP(sc) ((sc)->sc_ifp) 191 192 static const char stfname[] = "stf"; 193 194 static MALLOC_DEFINE(M_STF, stfname, "6to4 Tunnel Interface"); 195 static const int ip_stf_ttl = 40; 196 197 static int in_stf_input(struct mbuf *, int, int, void *); 198 static char *stfnames[] = {"stf0", "stf", "6to4", NULL}; 199 200 static int stfmodevent(module_t, int, void *); 201 static int stf_encapcheck(const struct mbuf *, int, int, void *); 202 static int stf_getsrcifa6(struct ifnet *, struct in6_addr *, struct in6_addr *); 203 static int stf_output(struct ifnet *, struct mbuf *, const struct sockaddr *, 204 struct route *); 205 static int isrfc1918addr(struct in_addr *); 206 static int stf_checkaddr4(struct stf_softc *, struct in_addr *, 207 struct ifnet *); 208 static int stf_checkaddr6(struct stf_softc *, struct in6_addr *, 209 struct ifnet *); 210 static struct sockaddr_in *stf_getin4addr_in6(struct stf_softc *, 211 struct sockaddr_in *, struct in6_addr, struct in6_addr, 212 struct in6_addr); 213 static struct sockaddr_in *stf_getin4addr(struct stf_softc *, 214 struct sockaddr_in *, struct in6_addr, struct in6_addr); 215 static int stf_ioctl(struct ifnet *, u_long, caddr_t); 216 217 VNET_DEFINE_STATIC(struct if_clone *, stf_cloner); 218 #define V_stf_cloner VNET(stf_cloner) 219 220 static const struct encap_config ipv4_encap_cfg = { 221 .proto = IPPROTO_IPV6, 222 .min_length = sizeof(struct ip), 223 .exact_match = (sizeof(in_addr_t) << 3) + 8, 224 .check = stf_encapcheck, 225 .input = in_stf_input 226 }; 227 228 static int 229 stf_clone_match(struct if_clone *ifc, const char *name) 230 { 231 int i; 232 233 for(i = 0; stfnames[i] != NULL; i++) { 234 if (strcmp(stfnames[i], name) == 0) 235 return (1); 236 } 237 238 return (0); 239 } 240 241 static int 242 stf_clone_create(struct if_clone *ifc, char *name, size_t len, 243 struct ifc_data *ifd, struct ifnet **ifpp) 244 { 245 char *dp; 246 int err, unit, wildcard; 247 struct stf_softc *sc; 248 struct ifnet *ifp; 249 250 err = ifc_name2unit(name, &unit); 251 if (err != 0) 252 return (err); 253 wildcard = (unit < 0); 254 255 /* 256 * We can only have one unit, but since unit allocation is 257 * already locked, we use it to keep from allocating extra 258 * interfaces. 259 */ 260 unit = STFUNIT; 261 err = ifc_alloc_unit(ifc, &unit); 262 if (err != 0) 263 return (err); 264 265 sc = malloc(sizeof(struct stf_softc), M_STF, M_WAITOK | M_ZERO); 266 ifp = STF2IFP(sc) = if_alloc(IFT_STF); 267 ifp->if_softc = sc; 268 sc->sc_fibnum = curthread->td_proc->p_fibnum; 269 270 /* 271 * Set the name manually rather then using if_initname because 272 * we don't conform to the default naming convention for interfaces. 273 * In the wildcard case, we need to update the name. 274 */ 275 if (wildcard) { 276 for (dp = name; *dp != '\0'; dp++); 277 if (snprintf(dp, len - (dp-name), "%d", unit) > 278 len - (dp-name) - 1) { 279 /* 280 * This can only be a programmer error and 281 * there's no straightforward way to recover if 282 * it happens. 283 */ 284 panic("if_clone_create(): interface name too long"); 285 } 286 } 287 strlcpy(ifp->if_xname, name, IFNAMSIZ); 288 ifp->if_dname = stfname; 289 ifp->if_dunit = IF_DUNIT_NONE; 290 291 sc->encap_cookie = ip_encap_attach(&ipv4_encap_cfg, sc, M_WAITOK); 292 293 ifp->if_mtu = IPV6_MMTU; 294 ifp->if_ioctl = stf_ioctl; 295 ifp->if_output = stf_output; 296 ifp->if_snd.ifq_maxlen = ifqmaxlen; 297 if_attach(ifp); 298 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t)); 299 *ifpp = ifp; 300 301 return (0); 302 } 303 304 static int 305 stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags) 306 { 307 struct stf_softc *sc = ifp->if_softc; 308 int err __unused; 309 310 err = ip_encap_detach(sc->encap_cookie); 311 KASSERT(err == 0, ("Unexpected error detaching encap_cookie")); 312 bpfdetach(ifp); 313 if_detach(ifp); 314 if_free(ifp); 315 316 free(sc, M_STF); 317 ifc_free_unit(ifc, STFUNIT); 318 319 return (0); 320 } 321 322 static void 323 vnet_stf_init(const void *unused __unused) 324 { 325 struct if_clone_addreq req = { 326 .match_f = stf_clone_match, 327 .create_f = stf_clone_create, 328 .destroy_f = stf_clone_destroy, 329 }; 330 V_stf_cloner = ifc_attach_cloner(stfname, &req); 331 } 332 VNET_SYSINIT(vnet_stf_init, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_init, NULL); 333 334 static void 335 vnet_stf_uninit(const void *unused __unused) 336 { 337 if_clone_detach(V_stf_cloner); 338 V_stf_cloner = NULL; 339 } 340 VNET_SYSUNINIT(vnet_stf_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_uninit, 341 NULL); 342 343 static int 344 stfmodevent(module_t mod, int type, void *data) 345 { 346 347 switch (type) { 348 case MOD_LOAD: 349 /* Done in vnet_stf_init() */ 350 break; 351 case MOD_UNLOAD: 352 /* Done in vnet_stf_uninit() */ 353 break; 354 default: 355 return (EOPNOTSUPP); 356 } 357 358 return (0); 359 } 360 361 static moduledata_t stf_mod = { 362 "if_stf", 363 stfmodevent, 364 0 365 }; 366 367 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 368 MODULE_VERSION(if_stf, 2); 369 370 static int 371 stf_encapcheck(const struct mbuf *m, int off, int proto, void *arg) 372 { 373 struct ip ip; 374 struct stf_softc *sc; 375 struct in6_addr addr6, mask6; 376 struct sockaddr_in sin4addr, sin4mask; 377 378 SDT_PROBE3(if_stf, , encapcheck, in, m, off, proto); 379 380 sc = (struct stf_softc *)arg; 381 if (sc == NULL) 382 return (0); 383 384 if ((STF2IFP(sc)->if_flags & IFF_UP) == 0) 385 return (0); 386 387 /* IFF_LINK0 means "no decapsulation" */ 388 if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0) 389 return (0); 390 391 if (proto != IPPROTO_IPV6) 392 return (0); 393 394 m_copydata(m, 0, sizeof(ip), (caddr_t)&ip); 395 396 if (ip.ip_v != 4) 397 return (0); 398 399 if (stf_getsrcifa6(STF2IFP(sc), &addr6, &mask6) != 0) 400 return (0); 401 402 if (sc->srcv4_addr != INADDR_ANY) { 403 sin4addr.sin_addr.s_addr = sc->srcv4_addr; 404 sin4addr.sin_family = AF_INET; 405 } else 406 if (stf_getin4addr(sc, &sin4addr, addr6, mask6) == NULL) 407 return (0); 408 409 if (sin4addr.sin_addr.s_addr != ip.ip_dst.s_addr) 410 return (0); 411 412 if (IN6_IS_ADDR_6TO4(&addr6)) { 413 /* 414 * 6to4 (RFC 3056). 415 * Check if IPv4 src matches the IPv4 address derived 416 * from the local 6to4 address masked by prefixmask. 417 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24 418 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24 419 */ 420 memcpy(&sin4mask.sin_addr, GET_V4(&mask6), 421 sizeof(sin4mask.sin_addr)); 422 if ((sin4addr.sin_addr.s_addr & sin4mask.sin_addr.s_addr) != 423 (ip.ip_src.s_addr & sin4mask.sin_addr.s_addr)) 424 return (0); 425 } else { 426 /* 6rd (RFC 5569) */ 427 /* 428 * No restriction on the src address in the case of 429 * 6rd because the stf(4) interface always has a 430 * prefix which covers whole of IPv4 src address 431 * range. So, stf_output() will catch all of 432 * 6rd-capsuled IPv4 traffic with suspicious inner dst 433 * IPv4 address (i.e. the IPv6 destination address is 434 * one the admin does not like to route to outside), 435 * and then it discard them silently. 436 */ 437 } 438 439 SDT_PROBE0(if_stf, , encapcheck, accept); 440 441 /* stf interface makes single side match only */ 442 return (32); 443 } 444 445 static int 446 stf_getsrcifa6(struct ifnet *ifp, struct in6_addr *addr, struct in6_addr *mask) 447 { 448 struct ifaddr *ia; 449 struct in_ifaddr *ia4; 450 struct in6_addr addr6, mask6; 451 struct sockaddr_in sin4; 452 struct stf_softc *sc; 453 struct in_addr in; 454 455 NET_EPOCH_ASSERT(); 456 457 sc = ifp->if_softc; 458 459 SDT_PROBE3(if_stf, , getsrcifa6, in, ifp, addr, mask); 460 461 CK_STAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 462 if (ia->ifa_addr->sa_family != AF_INET6) 463 continue; 464 465 addr6 = *IFA_IN6(ia); 466 mask6 = *IFA_MASKIN6(ia); 467 if (sc->srcv4_addr != INADDR_ANY) 468 bcopy(&sc->srcv4_addr, &in, sizeof(in)); 469 else { 470 if (stf_getin4addr(sc, &sin4, addr6, mask6) == NULL) 471 continue; 472 bcopy(&sin4.sin_addr, &in, sizeof(in)); 473 } 474 475 CK_LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash) 476 if (ia4->ia_addr.sin_addr.s_addr == in.s_addr) 477 break; 478 if (ia4 == NULL) 479 continue; 480 481 *addr = addr6; 482 *mask = mask6; 483 484 SDT_PROBE2(if_stf, , getsrcifa6, found, addr, mask); 485 486 return (0); 487 } 488 489 SDT_PROBE0(if_stf, , getsrcifa6, notfound); 490 491 return (ENOENT); 492 } 493 494 static int 495 stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 496 struct route *ro) 497 { 498 struct stf_softc *sc; 499 const struct sockaddr_in6 *dst6; 500 struct sockaddr_in dst4, src4; 501 u_int8_t tos; 502 struct ip *ip; 503 struct ip6_hdr *ip6; 504 struct in6_addr addr6, mask6; 505 int error; 506 507 SDT_PROBE4(if_stf, , stf_output, in, ifp, m, dst, ro); 508 509 #ifdef MAC 510 error = mac_ifnet_check_transmit(ifp, m); 511 if (error) { 512 m_freem(m); 513 SDT_PROBE2(if_stf, , stf_output, error, error, __LINE__); 514 return (error); 515 } 516 #endif 517 518 sc = ifp->if_softc; 519 dst6 = (const struct sockaddr_in6 *)dst; 520 521 /* just in case */ 522 if ((ifp->if_flags & IFF_UP) == 0) { 523 m_freem(m); 524 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 525 SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__); 526 return (ENETDOWN); 527 } 528 529 /* 530 * If we don't have an ip4 address that match my inner ip6 address, 531 * we shouldn't generate output. Without this check, we'll end up 532 * using wrong IPv4 source. 533 */ 534 if (stf_getsrcifa6(ifp, &addr6, &mask6) != 0) { 535 m_freem(m); 536 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 537 SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__); 538 return (ENETDOWN); 539 } 540 541 if (m->m_len < sizeof(*ip6)) { 542 m = m_pullup(m, sizeof(*ip6)); 543 if (!m) { 544 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 545 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, 546 __LINE__); 547 return (ENOBUFS); 548 } 549 } 550 ip6 = mtod(m, struct ip6_hdr *); 551 tos = IPV6_TRAFFIC_CLASS(ip6); 552 553 /* 554 * Pickup the right outer dst addr from the list of candidates. 555 * ip6_dst has priority as it may be able to give us shorter IPv4 hops. 556 */ 557 if (stf_getin4addr_in6(sc, &dst4, addr6, mask6, 558 ip6->ip6_dst) == NULL) { 559 if (sc->braddr != INADDR_ANY) 560 dst4.sin_addr.s_addr = sc->braddr; 561 else if (stf_getin4addr_in6(sc, &dst4, addr6, mask6, 562 dst6->sin6_addr) == NULL) { 563 m_freem(m); 564 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 565 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, 566 __LINE__); 567 return (ENETUNREACH); 568 } 569 } 570 571 if (bpf_peers_present(ifp->if_bpf)) { 572 /* 573 * We need to prepend the address family as 574 * a four byte field. Cons up a dummy header 575 * to pacify bpf. This is safe because bpf 576 * will only read from the mbuf (i.e., it won't 577 * try to free it or keep a pointer a to it). 578 */ 579 u_int af = AF_INET6; 580 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 581 } 582 583 M_PREPEND(m, sizeof(struct ip), M_NOWAIT); 584 if (m == NULL) { 585 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 586 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, __LINE__); 587 return (ENOBUFS); 588 } 589 ip = mtod(m, struct ip *); 590 591 bzero(ip, sizeof(*ip)); 592 593 if (sc->srcv4_addr != INADDR_ANY) 594 src4.sin_addr.s_addr = sc->srcv4_addr; 595 else if (stf_getin4addr(sc, &src4, addr6, mask6) == NULL) { 596 m_freem(m); 597 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 598 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, __LINE__); 599 return (ENETUNREACH); 600 } 601 bcopy(&src4.sin_addr, &ip->ip_src, sizeof(ip->ip_src)); 602 bcopy(&dst4.sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)); 603 604 ip->ip_p = IPPROTO_IPV6; 605 ip->ip_ttl = ip_stf_ttl; 606 ip->ip_len = htons(m->m_pkthdr.len); 607 if (ifp->if_flags & IFF_LINK1) 608 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos); 609 else 610 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos); 611 612 M_SETFIB(m, sc->sc_fibnum); 613 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); 614 error = ip_output(m, NULL, NULL, 0, NULL, NULL); 615 616 SDT_PROBE1(if_stf, , stf_output, out, error); 617 return (error); 618 } 619 620 static int 621 isrfc1918addr(struct in_addr *in) 622 { 623 /* 624 * returns 1 if private address range: 625 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 626 */ 627 if (stf_permit_rfc1918 == 0 && ( 628 (ntohl(in->s_addr) & 0xff000000) >> 24 == 10 || 629 (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 || 630 (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)) 631 return (1); 632 633 return (0); 634 } 635 636 static int 637 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in, struct ifnet *inifp) 638 { 639 struct in_ifaddr *ia4; 640 641 /* 642 * reject packets with the following address: 643 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8 644 */ 645 if (IN_MULTICAST(ntohl(in->s_addr))) 646 return (-1); 647 switch ((ntohl(in->s_addr) & 0xff000000) >> 24) { 648 case 0: case 127: case 255: 649 return (-1); 650 } 651 652 /* 653 * reject packets with broadcast 654 */ 655 CK_STAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) { 656 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0) 657 continue; 658 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr) { 659 return (-1); 660 } 661 } 662 663 /* 664 * perform ingress filter 665 */ 666 if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) { 667 struct nhop_object *nh; 668 669 NET_EPOCH_ASSERT(); 670 nh = fib4_lookup(sc->sc_fibnum, *in, 0, 0, 0); 671 if (nh == NULL) 672 return (-1); 673 674 if (nh->nh_ifp != inifp) 675 return (-1); 676 } 677 678 return (0); 679 } 680 681 static int 682 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6, struct ifnet *inifp) 683 { 684 SDT_PROBE3(if_stf, , checkaddr6, in, sc, in6, inifp); 685 686 /* 687 * check 6to4 addresses 688 */ 689 if (IN6_IS_ADDR_6TO4(in6)) { 690 struct in_addr in4; 691 int ret; 692 693 bcopy(GET_V4(in6), &in4, sizeof(in4)); 694 ret = stf_checkaddr4(sc, &in4, inifp); 695 SDT_PROBE2(if_stf, , checkaddr6, out, ret, __LINE__); 696 return (ret); 697 } 698 699 /* 700 * reject anything that look suspicious. the test is implemented 701 * in ip6_input too, but we check here as well to 702 * (1) reject bad packets earlier, and 703 * (2) to be safe against future ip6_input change. 704 */ 705 if (IN6_IS_ADDR_V4COMPAT(in6)) { 706 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__); 707 return (-1); 708 } 709 710 if (IN6_IS_ADDR_V4MAPPED(in6)) { 711 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__); 712 return (-1); 713 } 714 715 SDT_PROBE2(if_stf, , checkaddr6, out, 0, __LINE__); 716 return (0); 717 } 718 719 static int 720 in_stf_input(struct mbuf *m, int off, int proto, void *arg) 721 { 722 struct stf_softc *sc = arg; 723 struct ip ip; 724 struct ip6_hdr *ip6; 725 u_int8_t otos, itos; 726 struct ifnet *ifp; 727 struct nhop_object *nh; 728 729 NET_EPOCH_ASSERT(); 730 731 SDT_PROBE3(if_stf, , stf_input, in, m, off, proto); 732 733 if (proto != IPPROTO_IPV6) { 734 m_freem(m); 735 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 736 return (IPPROTO_DONE); 737 } 738 739 m_copydata(m, 0, sizeof(struct ip), (caddr_t)&ip); 740 if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) { 741 m_freem(m); 742 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 743 return (IPPROTO_DONE); 744 } 745 746 ifp = STF2IFP(sc); 747 748 #ifdef MAC 749 mac_ifnet_create_mbuf(ifp, m); 750 #endif 751 752 /* 753 * perform sanity check against outer src/dst. 754 * for source, perform ingress filter as well. 755 */ 756 if (stf_checkaddr4(sc, &ip.ip_dst, NULL) < 0 || 757 stf_checkaddr4(sc, &ip.ip_src, m->m_pkthdr.rcvif) < 0) { 758 m_freem(m); 759 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 760 return (IPPROTO_DONE); 761 } 762 763 otos = ip.ip_tos; 764 m_adj(m, off); 765 766 if (m->m_len < sizeof(*ip6)) { 767 m = m_pullup(m, sizeof(*ip6)); 768 if (!m) { 769 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, 770 __LINE__); 771 return (IPPROTO_DONE); 772 } 773 } 774 ip6 = mtod(m, struct ip6_hdr *); 775 776 /* 777 * perform sanity check against inner src/dst. 778 * for source, perform ingress filter as well. 779 */ 780 if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 || 781 stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) { 782 m_freem(m); 783 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 784 return (IPPROTO_DONE); 785 } 786 787 /* 788 * reject packets with private address range. 789 * (requirement from RFC3056 section 2 1st paragraph) 790 */ 791 if ((IN6_IS_ADDR_6TO4(&ip6->ip6_src) && isrfc1918addr(&ip.ip_src)) || 792 (IN6_IS_ADDR_6TO4(&ip6->ip6_dst) && isrfc1918addr(&ip.ip_dst))) { 793 m_freem(m); 794 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 795 return (IPPROTO_DONE); 796 } 797 798 /* 799 * Ignore if the destination is the same stf interface because 800 * all of valid IPv6 outgoing traffic should go interfaces 801 * except for it. 802 */ 803 nh = fib6_lookup(sc->sc_fibnum, &ip6->ip6_dst, 0, 0, 0); 804 if (nh == NULL) { 805 m_free(m); 806 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 807 return (IPPROTO_DONE); 808 } 809 if ((nh->nh_ifp == ifp) && 810 (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &nh->gw6_sa.sin6_addr))) { 811 m_free(m); 812 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 813 return (IPPROTO_DONE); 814 } 815 816 itos = IPV6_TRAFFIC_CLASS(ip6); 817 if ((ifp->if_flags & IFF_LINK1) != 0) 818 ip_ecn_egress(ECN_ALLOWED, &otos, &itos); 819 else 820 ip_ecn_egress(ECN_NOCARE, &otos, &itos); 821 ip6->ip6_flow &= ~htonl(0xff << 20); 822 ip6->ip6_flow |= htonl((u_int32_t)itos << 20); 823 824 m->m_pkthdr.rcvif = ifp; 825 826 if (bpf_peers_present(ifp->if_bpf)) { 827 /* 828 * We need to prepend the address family as 829 * a four byte field. Cons up a dummy header 830 * to pacify bpf. This is safe because bpf 831 * will only read from the mbuf (i.e., it won't 832 * try to free it or keep a pointer a to it). 833 */ 834 u_int32_t af = AF_INET6; 835 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 836 } 837 838 /* 839 * Put the packet to the network layer input queue according to the 840 * specified address family. 841 * See net/if_gif.c for possible issues with packet processing 842 * reorder due to extra queueing. 843 */ 844 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1); 845 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len); 846 M_SETFIB(m, ifp->if_fib); 847 netisr_dispatch(NETISR_IPV6, m); 848 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 849 return (IPPROTO_DONE); 850 } 851 852 static struct sockaddr_in * 853 stf_getin4addr_in6(struct stf_softc *sc, struct sockaddr_in *sin, 854 struct in6_addr addr6, struct in6_addr mask6, struct in6_addr in6) 855 { 856 int i; 857 struct sockaddr_in *out; 858 859 /* 860 * When (src addr & src mask) != (in6 & src mask), 861 * the dst is not in the 6rd domain. The IPv4 address must 862 * not be used. 863 */ 864 for (i = 0; i < sizeof(addr6); i++) { 865 if ((((u_char *)&addr6)[i] & ((u_char *)&mask6)[i]) != 866 (((u_char *)&in6)[i] & ((u_char *)&mask6)[i])) { 867 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, 868 &mask6, &in6, NULL); 869 return (NULL); 870 } 871 } 872 873 /* After the mask check, use in6 instead of addr6. */ 874 out = stf_getin4addr(sc, sin, in6, mask6); 875 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, &mask6, &in6, out); 876 return (out); 877 } 878 879 static struct sockaddr_in * 880 stf_getin4addr(struct stf_softc *sc, struct sockaddr_in *sin, 881 struct in6_addr addr6, struct in6_addr mask6) 882 { 883 struct in_addr *in; 884 885 SDT_PROBE2(if_stf, , getin4addr, in, &addr6, &mask6); 886 887 memset(sin, 0, sizeof(*sin)); 888 in = &sin->sin_addr; 889 if (IN6_IS_ADDR_6TO4(&addr6)) { 890 /* 6to4 (RFC 3056) */ 891 bcopy(GET_V4(&addr6), in, sizeof(*in)); 892 if (isrfc1918addr(in)) 893 return (NULL); 894 } else { 895 /* 6rd (RFC 5569) */ 896 in_addr_t v4prefix; 897 uint8_t *v6 = (uint8_t*)&addr6; 898 uint64_t v6prefix; 899 u_int plen; 900 u_int v4suffixlen; 901 902 v4prefix = 0; 903 if (sc->v4prefixlen < 32) { 904 v4suffixlen = 32 - sc->v4prefixlen; 905 v4prefix = ntohl(sc->srcv4_addr) & 906 (0xffffffffU << v4suffixlen); 907 } else { 908 MPASS(sc->v4prefixlen == 32); 909 v4suffixlen = 32; 910 } 911 912 plen = in6_mask2len(&mask6, NULL); 913 if (plen > 64) 914 return (NULL); 915 916 /* To make this simple we do not support prefixes longer than 917 * 64 bits. RFC5969 says "a 6rd delegated prefix SHOULD be /64 918 * or shorter." so this is a moderately safe assumption. */ 919 v6prefix = be64toh(*(uint64_t *)v6); 920 921 /* Shift away the v6 prefix itself. */ 922 v6prefix <<= plen; 923 v6prefix >>= plen; 924 925 /* Now shift away everything after the v4 address. */ 926 v6prefix >>= 64 - plen - v4suffixlen; 927 928 sin->sin_addr.s_addr = htonl(v4prefix | (uint32_t)v6prefix); 929 } 930 931 SDT_PROBE1(if_stf, , getin4addr, out, sin); 932 933 return (sin); 934 } 935 936 static int 937 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 938 { 939 struct ifaddr *ifa; 940 struct ifdrv *ifd; 941 struct ifreq *ifr; 942 struct sockaddr_in sin4; 943 struct stf_softc *sc_cur; 944 struct stfv4args args; 945 int error, mtu; 946 947 error = 0; 948 sc_cur = ifp->if_softc; 949 950 switch (cmd) { 951 case SIOCSDRVSPEC: 952 ifd = (struct ifdrv *)data; 953 error = priv_check(curthread, PRIV_NET_ADDIFADDR); 954 if (error) 955 break; 956 if (ifd->ifd_cmd == STF6RD_SV4NET) { 957 if (ifd->ifd_len != sizeof(args)) { 958 error = EINVAL; 959 break; 960 } 961 bzero(&args, sizeof(args)); 962 error = copyin(ifd->ifd_data, &args, ifd->ifd_len); 963 if (error) 964 break; 965 966 if (args.v4_prefixlen < 1 || args.v4_prefixlen > 32) { 967 error = EINVAL; 968 break; 969 } 970 971 bcopy(&args.srcv4_addr, &sc_cur->srcv4_addr, 972 sizeof(sc_cur->srcv4_addr)); 973 sc_cur->v4prefixlen = args.v4_prefixlen; 974 SDT_PROBE3(if_stf, , ioctl, sv4net, sc_cur->srcv4_addr, 975 sc_cur->srcv4_addr, sc_cur->v4prefixlen); 976 } else if (ifd->ifd_cmd == STF6RD_SBR) { 977 if (ifd->ifd_len != sizeof(args)) { 978 error = EINVAL; 979 break; 980 } 981 bzero(&args, sizeof(args)); 982 error = copyin(ifd->ifd_data, &args, ifd->ifd_len); 983 if (error) 984 break; 985 sc_cur->braddr = args.braddr.s_addr; 986 SDT_PROBE1(if_stf, , ioctl, sdstv4, 987 sc_cur->braddr); 988 } else 989 error = EINVAL; 990 break; 991 case SIOCGDRVSPEC: 992 ifd = (struct ifdrv *)data; 993 if (ifd->ifd_cmd != STF6RD_GV4NET) { 994 error = EINVAL; 995 break; 996 } 997 if (ifd->ifd_len != sizeof(args)) { 998 error = EINVAL; 999 break; 1000 } 1001 bzero(&args, sizeof(args)); 1002 args.srcv4_addr.s_addr = sc_cur->srcv4_addr; 1003 args.braddr.s_addr = sc_cur->braddr; 1004 args.v4_prefixlen = sc_cur->v4prefixlen; 1005 error = copyout(&args, ifd->ifd_data, ifd->ifd_len); 1006 break; 1007 case SIOCSIFADDR: 1008 ifa = (struct ifaddr *)data; 1009 SDT_PROBE1(if_stf, , ioctl, ifaddr, ifa); 1010 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) { 1011 error = EAFNOSUPPORT; 1012 break; 1013 } 1014 if (stf_getin4addr(sc_cur, &sin4, 1015 satosin6(ifa->ifa_addr)->sin6_addr, 1016 satosin6(ifa->ifa_netmask)->sin6_addr) == NULL) { 1017 error = EINVAL; 1018 break; 1019 } 1020 ifp->if_flags |= IFF_UP; 1021 ifp->if_drv_flags |= IFF_DRV_RUNNING; 1022 break; 1023 1024 case SIOCADDMULTI: 1025 case SIOCDELMULTI: 1026 ifr = (struct ifreq *)data; 1027 if (ifr && ifr->ifr_addr.sa_family == AF_INET6) 1028 ; 1029 else 1030 error = EAFNOSUPPORT; 1031 break; 1032 1033 case SIOCGIFMTU: 1034 break; 1035 1036 case SIOCSIFMTU: 1037 ifr = (struct ifreq *)data; 1038 mtu = ifr->ifr_mtu; 1039 /* RFC 4213 3.2 ideal world MTU */ 1040 if (mtu < IPV6_MINMTU || mtu > IF_MAXMTU - 20) 1041 return (EINVAL); 1042 ifp->if_mtu = mtu; 1043 break; 1044 1045 default: 1046 error = EINVAL; 1047 break; 1048 } 1049 1050 return (error); 1051 } 1052