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 if (ifp == NULL) { 268 free(sc, M_STF); 269 ifc_free_unit(ifc, unit); 270 return (ENOSPC); 271 } 272 ifp->if_softc = sc; 273 sc->sc_fibnum = curthread->td_proc->p_fibnum; 274 275 /* 276 * Set the name manually rather then using if_initname because 277 * we don't conform to the default naming convention for interfaces. 278 * In the wildcard case, we need to update the name. 279 */ 280 if (wildcard) { 281 for (dp = name; *dp != '\0'; dp++); 282 if (snprintf(dp, len - (dp-name), "%d", unit) > 283 len - (dp-name) - 1) { 284 /* 285 * This can only be a programmer error and 286 * there's no straightforward way to recover if 287 * it happens. 288 */ 289 panic("if_clone_create(): interface name too long"); 290 } 291 } 292 strlcpy(ifp->if_xname, name, IFNAMSIZ); 293 ifp->if_dname = stfname; 294 ifp->if_dunit = IF_DUNIT_NONE; 295 296 sc->encap_cookie = ip_encap_attach(&ipv4_encap_cfg, sc, M_WAITOK); 297 298 ifp->if_mtu = IPV6_MMTU; 299 ifp->if_ioctl = stf_ioctl; 300 ifp->if_output = stf_output; 301 ifp->if_snd.ifq_maxlen = ifqmaxlen; 302 if_attach(ifp); 303 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t)); 304 *ifpp = ifp; 305 306 return (0); 307 } 308 309 static int 310 stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags) 311 { 312 struct stf_softc *sc = ifp->if_softc; 313 int err __unused; 314 315 err = ip_encap_detach(sc->encap_cookie); 316 KASSERT(err == 0, ("Unexpected error detaching encap_cookie")); 317 bpfdetach(ifp); 318 if_detach(ifp); 319 if_free(ifp); 320 321 free(sc, M_STF); 322 ifc_free_unit(ifc, STFUNIT); 323 324 return (0); 325 } 326 327 static void 328 vnet_stf_init(const void *unused __unused) 329 { 330 struct if_clone_addreq req = { 331 .match_f = stf_clone_match, 332 .create_f = stf_clone_create, 333 .destroy_f = stf_clone_destroy, 334 }; 335 V_stf_cloner = ifc_attach_cloner(stfname, &req); 336 } 337 VNET_SYSINIT(vnet_stf_init, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_init, NULL); 338 339 static void 340 vnet_stf_uninit(const void *unused __unused) 341 { 342 if_clone_detach(V_stf_cloner); 343 V_stf_cloner = NULL; 344 } 345 VNET_SYSUNINIT(vnet_stf_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_uninit, 346 NULL); 347 348 static int 349 stfmodevent(module_t mod, int type, void *data) 350 { 351 352 switch (type) { 353 case MOD_LOAD: 354 /* Done in vnet_stf_init() */ 355 break; 356 case MOD_UNLOAD: 357 /* Done in vnet_stf_uninit() */ 358 break; 359 default: 360 return (EOPNOTSUPP); 361 } 362 363 return (0); 364 } 365 366 static moduledata_t stf_mod = { 367 "if_stf", 368 stfmodevent, 369 0 370 }; 371 372 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 373 MODULE_VERSION(if_stf, 2); 374 375 static int 376 stf_encapcheck(const struct mbuf *m, int off, int proto, void *arg) 377 { 378 struct ip ip; 379 struct stf_softc *sc; 380 struct in6_addr addr6, mask6; 381 struct sockaddr_in sin4addr, sin4mask; 382 383 SDT_PROBE3(if_stf, , encapcheck, in, m, off, proto); 384 385 sc = (struct stf_softc *)arg; 386 if (sc == NULL) 387 return (0); 388 389 if ((STF2IFP(sc)->if_flags & IFF_UP) == 0) 390 return (0); 391 392 /* IFF_LINK0 means "no decapsulation" */ 393 if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0) 394 return (0); 395 396 if (proto != IPPROTO_IPV6) 397 return (0); 398 399 m_copydata(m, 0, sizeof(ip), (caddr_t)&ip); 400 401 if (ip.ip_v != 4) 402 return (0); 403 404 if (stf_getsrcifa6(STF2IFP(sc), &addr6, &mask6) != 0) 405 return (0); 406 407 if (sc->srcv4_addr != INADDR_ANY) { 408 sin4addr.sin_addr.s_addr = sc->srcv4_addr; 409 sin4addr.sin_family = AF_INET; 410 } else 411 if (stf_getin4addr(sc, &sin4addr, addr6, mask6) == NULL) 412 return (0); 413 414 if (sin4addr.sin_addr.s_addr != ip.ip_dst.s_addr) 415 return (0); 416 417 if (IN6_IS_ADDR_6TO4(&addr6)) { 418 /* 419 * 6to4 (RFC 3056). 420 * Check if IPv4 src matches the IPv4 address derived 421 * from the local 6to4 address masked by prefixmask. 422 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24 423 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24 424 */ 425 memcpy(&sin4mask.sin_addr, GET_V4(&mask6), 426 sizeof(sin4mask.sin_addr)); 427 if ((sin4addr.sin_addr.s_addr & sin4mask.sin_addr.s_addr) != 428 (ip.ip_src.s_addr & sin4mask.sin_addr.s_addr)) 429 return (0); 430 } else { 431 /* 6rd (RFC 5569) */ 432 /* 433 * No restriction on the src address in the case of 434 * 6rd because the stf(4) interface always has a 435 * prefix which covers whole of IPv4 src address 436 * range. So, stf_output() will catch all of 437 * 6rd-capsuled IPv4 traffic with suspicious inner dst 438 * IPv4 address (i.e. the IPv6 destination address is 439 * one the admin does not like to route to outside), 440 * and then it discard them silently. 441 */ 442 } 443 444 SDT_PROBE0(if_stf, , encapcheck, accept); 445 446 /* stf interface makes single side match only */ 447 return (32); 448 } 449 450 static int 451 stf_getsrcifa6(struct ifnet *ifp, struct in6_addr *addr, struct in6_addr *mask) 452 { 453 struct ifaddr *ia; 454 struct in_ifaddr *ia4; 455 struct in6_addr addr6, mask6; 456 struct sockaddr_in sin4; 457 struct stf_softc *sc; 458 struct in_addr in; 459 460 NET_EPOCH_ASSERT(); 461 462 sc = ifp->if_softc; 463 464 SDT_PROBE3(if_stf, , getsrcifa6, in, ifp, addr, mask); 465 466 CK_STAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 467 if (ia->ifa_addr->sa_family != AF_INET6) 468 continue; 469 470 addr6 = *IFA_IN6(ia); 471 mask6 = *IFA_MASKIN6(ia); 472 if (sc->srcv4_addr != INADDR_ANY) 473 bcopy(&sc->srcv4_addr, &in, sizeof(in)); 474 else { 475 if (stf_getin4addr(sc, &sin4, addr6, mask6) == NULL) 476 continue; 477 bcopy(&sin4.sin_addr, &in, sizeof(in)); 478 } 479 480 CK_LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash) 481 if (ia4->ia_addr.sin_addr.s_addr == in.s_addr) 482 break; 483 if (ia4 == NULL) 484 continue; 485 486 *addr = addr6; 487 *mask = mask6; 488 489 SDT_PROBE2(if_stf, , getsrcifa6, found, addr, mask); 490 491 return (0); 492 } 493 494 SDT_PROBE0(if_stf, , getsrcifa6, notfound); 495 496 return (ENOENT); 497 } 498 499 static int 500 stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 501 struct route *ro) 502 { 503 struct stf_softc *sc; 504 const struct sockaddr_in6 *dst6; 505 struct sockaddr_in dst4, src4; 506 u_int8_t tos; 507 struct ip *ip; 508 struct ip6_hdr *ip6; 509 struct in6_addr addr6, mask6; 510 int error; 511 512 SDT_PROBE4(if_stf, , stf_output, in, ifp, m, dst, ro); 513 514 #ifdef MAC 515 error = mac_ifnet_check_transmit(ifp, m); 516 if (error) { 517 m_freem(m); 518 SDT_PROBE2(if_stf, , stf_output, error, error, __LINE__); 519 return (error); 520 } 521 #endif 522 523 sc = ifp->if_softc; 524 dst6 = (const struct sockaddr_in6 *)dst; 525 526 /* just in case */ 527 if ((ifp->if_flags & IFF_UP) == 0) { 528 m_freem(m); 529 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 530 SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__); 531 return (ENETDOWN); 532 } 533 534 /* 535 * If we don't have an ip4 address that match my inner ip6 address, 536 * we shouldn't generate output. Without this check, we'll end up 537 * using wrong IPv4 source. 538 */ 539 if (stf_getsrcifa6(ifp, &addr6, &mask6) != 0) { 540 m_freem(m); 541 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 542 SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__); 543 return (ENETDOWN); 544 } 545 546 if (m->m_len < sizeof(*ip6)) { 547 m = m_pullup(m, sizeof(*ip6)); 548 if (!m) { 549 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 550 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, 551 __LINE__); 552 return (ENOBUFS); 553 } 554 } 555 ip6 = mtod(m, struct ip6_hdr *); 556 tos = IPV6_TRAFFIC_CLASS(ip6); 557 558 /* 559 * Pickup the right outer dst addr from the list of candidates. 560 * ip6_dst has priority as it may be able to give us shorter IPv4 hops. 561 */ 562 if (stf_getin4addr_in6(sc, &dst4, addr6, mask6, 563 ip6->ip6_dst) == NULL) { 564 if (sc->braddr != INADDR_ANY) 565 dst4.sin_addr.s_addr = sc->braddr; 566 else if (stf_getin4addr_in6(sc, &dst4, addr6, mask6, 567 dst6->sin6_addr) == NULL) { 568 m_freem(m); 569 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 570 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, 571 __LINE__); 572 return (ENETUNREACH); 573 } 574 } 575 576 if (bpf_peers_present(ifp->if_bpf)) { 577 /* 578 * We need to prepend the address family as 579 * a four byte field. Cons up a dummy header 580 * to pacify bpf. This is safe because bpf 581 * will only read from the mbuf (i.e., it won't 582 * try to free it or keep a pointer a to it). 583 */ 584 u_int af = AF_INET6; 585 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 586 } 587 588 M_PREPEND(m, sizeof(struct ip), M_NOWAIT); 589 if (m == NULL) { 590 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 591 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, __LINE__); 592 return (ENOBUFS); 593 } 594 ip = mtod(m, struct ip *); 595 596 bzero(ip, sizeof(*ip)); 597 598 if (sc->srcv4_addr != INADDR_ANY) 599 src4.sin_addr.s_addr = sc->srcv4_addr; 600 else if (stf_getin4addr(sc, &src4, addr6, mask6) == NULL) { 601 m_freem(m); 602 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 603 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, __LINE__); 604 return (ENETUNREACH); 605 } 606 bcopy(&src4.sin_addr, &ip->ip_src, sizeof(ip->ip_src)); 607 bcopy(&dst4.sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)); 608 609 ip->ip_p = IPPROTO_IPV6; 610 ip->ip_ttl = ip_stf_ttl; 611 ip->ip_len = htons(m->m_pkthdr.len); 612 if (ifp->if_flags & IFF_LINK1) 613 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos); 614 else 615 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos); 616 617 M_SETFIB(m, sc->sc_fibnum); 618 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); 619 error = ip_output(m, NULL, NULL, 0, NULL, NULL); 620 621 SDT_PROBE1(if_stf, , stf_output, out, error); 622 return (error); 623 } 624 625 static int 626 isrfc1918addr(struct in_addr *in) 627 { 628 /* 629 * returns 1 if private address range: 630 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 631 */ 632 if (stf_permit_rfc1918 == 0 && ( 633 (ntohl(in->s_addr) & 0xff000000) >> 24 == 10 || 634 (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 || 635 (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)) 636 return (1); 637 638 return (0); 639 } 640 641 static int 642 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in, struct ifnet *inifp) 643 { 644 struct in_ifaddr *ia4; 645 646 /* 647 * reject packets with the following address: 648 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8 649 */ 650 if (IN_MULTICAST(ntohl(in->s_addr))) 651 return (-1); 652 switch ((ntohl(in->s_addr) & 0xff000000) >> 24) { 653 case 0: case 127: case 255: 654 return (-1); 655 } 656 657 /* 658 * reject packets with broadcast 659 */ 660 CK_STAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) { 661 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0) 662 continue; 663 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr) { 664 return (-1); 665 } 666 } 667 668 /* 669 * perform ingress filter 670 */ 671 if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) { 672 struct nhop_object *nh; 673 674 NET_EPOCH_ASSERT(); 675 nh = fib4_lookup(sc->sc_fibnum, *in, 0, 0, 0); 676 if (nh == NULL) 677 return (-1); 678 679 if (nh->nh_ifp != inifp) 680 return (-1); 681 } 682 683 return (0); 684 } 685 686 static int 687 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6, struct ifnet *inifp) 688 { 689 SDT_PROBE3(if_stf, , checkaddr6, in, sc, in6, inifp); 690 691 /* 692 * check 6to4 addresses 693 */ 694 if (IN6_IS_ADDR_6TO4(in6)) { 695 struct in_addr in4; 696 int ret; 697 698 bcopy(GET_V4(in6), &in4, sizeof(in4)); 699 ret = stf_checkaddr4(sc, &in4, inifp); 700 SDT_PROBE2(if_stf, , checkaddr6, out, ret, __LINE__); 701 return (ret); 702 } 703 704 /* 705 * reject anything that look suspicious. the test is implemented 706 * in ip6_input too, but we check here as well to 707 * (1) reject bad packets earlier, and 708 * (2) to be safe against future ip6_input change. 709 */ 710 if (IN6_IS_ADDR_V4COMPAT(in6)) { 711 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__); 712 return (-1); 713 } 714 715 if (IN6_IS_ADDR_V4MAPPED(in6)) { 716 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__); 717 return (-1); 718 } 719 720 SDT_PROBE2(if_stf, , checkaddr6, out, 0, __LINE__); 721 return (0); 722 } 723 724 static int 725 in_stf_input(struct mbuf *m, int off, int proto, void *arg) 726 { 727 struct stf_softc *sc = arg; 728 struct ip ip; 729 struct ip6_hdr *ip6; 730 u_int8_t otos, itos; 731 struct ifnet *ifp; 732 struct nhop_object *nh; 733 734 NET_EPOCH_ASSERT(); 735 736 SDT_PROBE3(if_stf, , stf_input, in, m, off, proto); 737 738 if (proto != IPPROTO_IPV6) { 739 m_freem(m); 740 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 741 return (IPPROTO_DONE); 742 } 743 744 m_copydata(m, 0, sizeof(struct ip), (caddr_t)&ip); 745 if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) { 746 m_freem(m); 747 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 748 return (IPPROTO_DONE); 749 } 750 751 ifp = STF2IFP(sc); 752 753 #ifdef MAC 754 mac_ifnet_create_mbuf(ifp, m); 755 #endif 756 757 /* 758 * perform sanity check against outer src/dst. 759 * for source, perform ingress filter as well. 760 */ 761 if (stf_checkaddr4(sc, &ip.ip_dst, NULL) < 0 || 762 stf_checkaddr4(sc, &ip.ip_src, m->m_pkthdr.rcvif) < 0) { 763 m_freem(m); 764 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 765 return (IPPROTO_DONE); 766 } 767 768 otos = ip.ip_tos; 769 m_adj(m, off); 770 771 if (m->m_len < sizeof(*ip6)) { 772 m = m_pullup(m, sizeof(*ip6)); 773 if (!m) { 774 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, 775 __LINE__); 776 return (IPPROTO_DONE); 777 } 778 } 779 ip6 = mtod(m, struct ip6_hdr *); 780 781 /* 782 * perform sanity check against inner src/dst. 783 * for source, perform ingress filter as well. 784 */ 785 if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 || 786 stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) { 787 m_freem(m); 788 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 789 return (IPPROTO_DONE); 790 } 791 792 /* 793 * reject packets with private address range. 794 * (requirement from RFC3056 section 2 1st paragraph) 795 */ 796 if ((IN6_IS_ADDR_6TO4(&ip6->ip6_src) && isrfc1918addr(&ip.ip_src)) || 797 (IN6_IS_ADDR_6TO4(&ip6->ip6_dst) && isrfc1918addr(&ip.ip_dst))) { 798 m_freem(m); 799 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 800 return (IPPROTO_DONE); 801 } 802 803 /* 804 * Ignore if the destination is the same stf interface because 805 * all of valid IPv6 outgoing traffic should go interfaces 806 * except for it. 807 */ 808 nh = fib6_lookup(sc->sc_fibnum, &ip6->ip6_dst, 0, 0, 0); 809 if (nh == NULL) { 810 m_free(m); 811 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 812 return (IPPROTO_DONE); 813 } 814 if ((nh->nh_ifp == ifp) && 815 (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &nh->gw6_sa.sin6_addr))) { 816 m_free(m); 817 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 818 return (IPPROTO_DONE); 819 } 820 821 itos = IPV6_TRAFFIC_CLASS(ip6); 822 if ((ifp->if_flags & IFF_LINK1) != 0) 823 ip_ecn_egress(ECN_ALLOWED, &otos, &itos); 824 else 825 ip_ecn_egress(ECN_NOCARE, &otos, &itos); 826 ip6->ip6_flow &= ~htonl(0xff << 20); 827 ip6->ip6_flow |= htonl((u_int32_t)itos << 20); 828 829 m->m_pkthdr.rcvif = ifp; 830 831 if (bpf_peers_present(ifp->if_bpf)) { 832 /* 833 * We need to prepend the address family as 834 * a four byte field. Cons up a dummy header 835 * to pacify bpf. This is safe because bpf 836 * will only read from the mbuf (i.e., it won't 837 * try to free it or keep a pointer a to it). 838 */ 839 u_int32_t af = AF_INET6; 840 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 841 } 842 843 /* 844 * Put the packet to the network layer input queue according to the 845 * specified address family. 846 * See net/if_gif.c for possible issues with packet processing 847 * reorder due to extra queueing. 848 */ 849 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1); 850 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len); 851 M_SETFIB(m, ifp->if_fib); 852 netisr_dispatch(NETISR_IPV6, m); 853 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 854 return (IPPROTO_DONE); 855 } 856 857 static struct sockaddr_in * 858 stf_getin4addr_in6(struct stf_softc *sc, struct sockaddr_in *sin, 859 struct in6_addr addr6, struct in6_addr mask6, struct in6_addr in6) 860 { 861 int i; 862 struct sockaddr_in *out; 863 864 /* 865 * When (src addr & src mask) != (in6 & src mask), 866 * the dst is not in the 6rd domain. The IPv4 address must 867 * not be used. 868 */ 869 for (i = 0; i < sizeof(addr6); i++) { 870 if ((((u_char *)&addr6)[i] & ((u_char *)&mask6)[i]) != 871 (((u_char *)&in6)[i] & ((u_char *)&mask6)[i])) { 872 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, 873 &mask6, &in6, NULL); 874 return (NULL); 875 } 876 } 877 878 /* After the mask check, use in6 instead of addr6. */ 879 out = stf_getin4addr(sc, sin, in6, mask6); 880 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, &mask6, &in6, out); 881 return (out); 882 } 883 884 static struct sockaddr_in * 885 stf_getin4addr(struct stf_softc *sc, struct sockaddr_in *sin, 886 struct in6_addr addr6, struct in6_addr mask6) 887 { 888 struct in_addr *in; 889 890 SDT_PROBE2(if_stf, , getin4addr, in, &addr6, &mask6); 891 892 memset(sin, 0, sizeof(*sin)); 893 in = &sin->sin_addr; 894 if (IN6_IS_ADDR_6TO4(&addr6)) { 895 /* 6to4 (RFC 3056) */ 896 bcopy(GET_V4(&addr6), in, sizeof(*in)); 897 if (isrfc1918addr(in)) 898 return (NULL); 899 } else { 900 /* 6rd (RFC 5569) */ 901 in_addr_t v4prefix; 902 uint8_t *v6 = (uint8_t*)&addr6; 903 uint64_t v6prefix; 904 u_int plen; 905 u_int v4suffixlen; 906 907 v4prefix = 0; 908 if (sc->v4prefixlen < 32) { 909 v4suffixlen = 32 - sc->v4prefixlen; 910 v4prefix = ntohl(sc->srcv4_addr) & 911 (0xffffffffU << v4suffixlen); 912 } else { 913 MPASS(sc->v4prefixlen == 32); 914 v4suffixlen = 32; 915 } 916 917 plen = in6_mask2len(&mask6, NULL); 918 if (plen > 64) 919 return (NULL); 920 921 /* To make this simple we do not support prefixes longer than 922 * 64 bits. RFC5969 says "a 6rd delegated prefix SHOULD be /64 923 * or shorter." so this is a moderately safe assumption. */ 924 v6prefix = be64toh(*(uint64_t *)v6); 925 926 /* Shift away the v6 prefix itself. */ 927 v6prefix <<= plen; 928 v6prefix >>= plen; 929 930 /* Now shift away everything after the v4 address. */ 931 v6prefix >>= 64 - plen - v4suffixlen; 932 933 sin->sin_addr.s_addr = htonl(v4prefix | (uint32_t)v6prefix); 934 } 935 936 SDT_PROBE1(if_stf, , getin4addr, out, sin); 937 938 return (sin); 939 } 940 941 static int 942 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 943 { 944 struct ifaddr *ifa; 945 struct ifdrv *ifd; 946 struct ifreq *ifr; 947 struct sockaddr_in sin4; 948 struct stf_softc *sc_cur; 949 struct stfv4args args; 950 int error, mtu; 951 952 error = 0; 953 sc_cur = ifp->if_softc; 954 955 switch (cmd) { 956 case SIOCSDRVSPEC: 957 ifd = (struct ifdrv *)data; 958 error = priv_check(curthread, PRIV_NET_ADDIFADDR); 959 if (error) 960 break; 961 if (ifd->ifd_cmd == STF6RD_SV4NET) { 962 if (ifd->ifd_len != sizeof(args)) { 963 error = EINVAL; 964 break; 965 } 966 bzero(&args, sizeof(args)); 967 error = copyin(ifd->ifd_data, &args, ifd->ifd_len); 968 if (error) 969 break; 970 971 if (args.v4_prefixlen < 1 || args.v4_prefixlen > 32) { 972 error = EINVAL; 973 break; 974 } 975 976 bcopy(&args.srcv4_addr, &sc_cur->srcv4_addr, 977 sizeof(sc_cur->srcv4_addr)); 978 sc_cur->v4prefixlen = args.v4_prefixlen; 979 SDT_PROBE3(if_stf, , ioctl, sv4net, sc_cur->srcv4_addr, 980 sc_cur->srcv4_addr, sc_cur->v4prefixlen); 981 } else if (ifd->ifd_cmd == STF6RD_SBR) { 982 if (ifd->ifd_len != sizeof(args)) { 983 error = EINVAL; 984 break; 985 } 986 bzero(&args, sizeof(args)); 987 error = copyin(ifd->ifd_data, &args, ifd->ifd_len); 988 if (error) 989 break; 990 sc_cur->braddr = args.braddr.s_addr; 991 SDT_PROBE1(if_stf, , ioctl, sdstv4, 992 sc_cur->braddr); 993 } else 994 error = EINVAL; 995 break; 996 case SIOCGDRVSPEC: 997 ifd = (struct ifdrv *)data; 998 if (ifd->ifd_cmd != STF6RD_GV4NET) { 999 error = EINVAL; 1000 break; 1001 } 1002 if (ifd->ifd_len != sizeof(args)) { 1003 error = EINVAL; 1004 break; 1005 } 1006 bzero(&args, sizeof(args)); 1007 args.srcv4_addr.s_addr = sc_cur->srcv4_addr; 1008 args.braddr.s_addr = sc_cur->braddr; 1009 args.v4_prefixlen = sc_cur->v4prefixlen; 1010 error = copyout(&args, ifd->ifd_data, ifd->ifd_len); 1011 break; 1012 case SIOCSIFADDR: 1013 ifa = (struct ifaddr *)data; 1014 SDT_PROBE1(if_stf, , ioctl, ifaddr, ifa); 1015 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) { 1016 error = EAFNOSUPPORT; 1017 break; 1018 } 1019 if (stf_getin4addr(sc_cur, &sin4, 1020 satosin6(ifa->ifa_addr)->sin6_addr, 1021 satosin6(ifa->ifa_netmask)->sin6_addr) == NULL) { 1022 error = EINVAL; 1023 break; 1024 } 1025 ifp->if_flags |= IFF_UP; 1026 ifp->if_drv_flags |= IFF_DRV_RUNNING; 1027 break; 1028 1029 case SIOCADDMULTI: 1030 case SIOCDELMULTI: 1031 ifr = (struct ifreq *)data; 1032 if (ifr && ifr->ifr_addr.sa_family == AF_INET6) 1033 ; 1034 else 1035 error = EAFNOSUPPORT; 1036 break; 1037 1038 case SIOCGIFMTU: 1039 break; 1040 1041 case SIOCSIFMTU: 1042 ifr = (struct ifreq *)data; 1043 mtu = ifr->ifr_mtu; 1044 /* RFC 4213 3.2 ideal world MTU */ 1045 if (mtu < IPV6_MINMTU || mtu > IF_MAXMTU - 20) 1046 return (EINVAL); 1047 ifp->if_mtu = mtu; 1048 break; 1049 1050 default: 1051 error = EINVAL; 1052 break; 1053 } 1054 1055 return (error); 1056 } 1057