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