1 /* $FreeBSD$ */ 2 /* $KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi Exp $ */ 3 4 /*- 5 * SPDX-License-Identifier: BSD-3-Clause 6 * 7 * Copyright (C) 2000 WIDE Project. 8 * Copyright (c) 2010 Hiroki Sato <hrs@FreeBSD.org> 9 * Copyright (c) 2013 Ermal Luci <eri@FreeBSD.org> 10 * Copyright (c) 2017-2021 Rubicon Communications, LLC (Netgate) 11 * All rights reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the project nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 38 /* 39 * 6to4 interface, based on RFC3056. 40 * 41 * 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting. 42 * There is no address mapping defined from IPv6 multicast address to IPv4 43 * address. Therefore, we do not have IFF_MULTICAST on the interface. 44 * 45 * Due to the lack of address mapping for link-local addresses, we cannot 46 * throw packets toward link-local addresses (fe80::x). Also, we cannot throw 47 * packets to link-local multicast addresses (ff02::x). 48 * 49 * Here are interesting symptoms due to the lack of link-local address: 50 * 51 * Unicast routing exchange: 52 * - RIPng: Impossible. Uses link-local multicast packet toward ff02::9, 53 * and link-local addresses as nexthop. 54 * - OSPFv6: Impossible. OSPFv6 assumes that there's link-local address 55 * assigned to the link, and makes use of them. Also, HELLO packets use 56 * link-local multicast addresses (ff02::5 and ff02::6). 57 * - BGP4+: Maybe. You can only use global address as nexthop, and global 58 * address as TCP endpoint address. 59 * 60 * Multicast routing protocols: 61 * - PIM: Hello packet cannot be used to discover adjacent PIM routers. 62 * Adjacent PIM routers must be configured manually (is it really spec-wise 63 * correct thing to do?). 64 * 65 * ICMPv6: 66 * - Redirects cannot be used due to the lack of link-local address. 67 * 68 * stf interface does not have, and will not need, a link-local address. 69 * It seems to have no real benefit and does not help the above symptoms much. 70 * Even if we assign link-locals to interface, we cannot really 71 * use link-local unicast/multicast on top of 6to4 cloud (since there's no 72 * encapsulation defined for link-local address), and the above analysis does 73 * not change. RFC3056 does not mandate the assignment of link-local address 74 * either. 75 * 76 * 6to4 interface has security issues. Refer to 77 * http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt 78 * for details. The code tries to filter out some of malicious packets. 79 * Note that there is no way to be 100% secure. 80 */ 81 82 #include <sys/param.h> 83 #include <sys/systm.h> 84 #include <sys/socket.h> 85 #include <sys/sockio.h> 86 #include <sys/mbuf.h> 87 #include <sys/endian.h> 88 #include <sys/errno.h> 89 #include <sys/kernel.h> 90 #include <sys/lock.h> 91 #include <sys/module.h> 92 #include <sys/priv.h> 93 #include <sys/proc.h> 94 #include <sys/queue.h> 95 #include <sys/sdt.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_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 if (sc->encap_cookie == NULL) { 298 if_printf(ifp, "attach failed\n"); 299 free(sc, M_STF); 300 ifc_free_unit(ifc, unit); 301 return (ENOMEM); 302 } 303 304 ifp->if_mtu = IPV6_MMTU; 305 ifp->if_ioctl = stf_ioctl; 306 ifp->if_output = stf_output; 307 ifp->if_snd.ifq_maxlen = ifqmaxlen; 308 if_attach(ifp); 309 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t)); 310 *ifpp = ifp; 311 312 return (0); 313 } 314 315 static int 316 stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags) 317 { 318 struct stf_softc *sc = ifp->if_softc; 319 int err __unused; 320 321 err = ip_encap_detach(sc->encap_cookie); 322 KASSERT(err == 0, ("Unexpected error detaching encap_cookie")); 323 bpfdetach(ifp); 324 if_detach(ifp); 325 if_free(ifp); 326 327 free(sc, M_STF); 328 ifc_free_unit(ifc, STFUNIT); 329 330 return (0); 331 } 332 333 static void 334 vnet_stf_init(const void *unused __unused) 335 { 336 struct if_clone_addreq req = { 337 .match_f = stf_clone_match, 338 .create_f = stf_clone_create, 339 .destroy_f = stf_clone_destroy, 340 }; 341 V_stf_cloner = ifc_attach_cloner(stfname, &req); 342 } 343 VNET_SYSINIT(vnet_stf_init, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_init, NULL); 344 345 static void 346 vnet_stf_uninit(const void *unused __unused) 347 { 348 if_clone_detach(V_stf_cloner); 349 V_stf_cloner = NULL; 350 } 351 VNET_SYSUNINIT(vnet_stf_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_uninit, 352 NULL); 353 354 static int 355 stfmodevent(module_t mod, int type, void *data) 356 { 357 358 switch (type) { 359 case MOD_LOAD: 360 /* Done in vnet_stf_init() */ 361 break; 362 case MOD_UNLOAD: 363 /* Done in vnet_stf_uninit() */ 364 break; 365 default: 366 return (EOPNOTSUPP); 367 } 368 369 return (0); 370 } 371 372 static moduledata_t stf_mod = { 373 "if_stf", 374 stfmodevent, 375 0 376 }; 377 378 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 379 MODULE_VERSION(if_stf, 2); 380 381 static int 382 stf_encapcheck(const struct mbuf *m, int off, int proto, void *arg) 383 { 384 struct ip ip; 385 struct stf_softc *sc; 386 struct in6_addr addr6, mask6; 387 struct sockaddr_in sin4addr, sin4mask; 388 389 SDT_PROBE3(if_stf, , encapcheck, in, m, off, proto); 390 391 sc = (struct stf_softc *)arg; 392 if (sc == NULL) 393 return (0); 394 395 if ((STF2IFP(sc)->if_flags & IFF_UP) == 0) 396 return (0); 397 398 /* IFF_LINK0 means "no decapsulation" */ 399 if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0) 400 return (0); 401 402 if (proto != IPPROTO_IPV6) 403 return (0); 404 405 m_copydata(m, 0, sizeof(ip), (caddr_t)&ip); 406 407 if (ip.ip_v != 4) 408 return (0); 409 410 if (stf_getsrcifa6(STF2IFP(sc), &addr6, &mask6) != 0) 411 return (0); 412 413 if (sc->srcv4_addr != INADDR_ANY) { 414 sin4addr.sin_addr.s_addr = sc->srcv4_addr; 415 sin4addr.sin_family = AF_INET; 416 } else 417 if (stf_getin4addr(sc, &sin4addr, addr6, mask6) == NULL) 418 return (0); 419 420 if (sin4addr.sin_addr.s_addr != ip.ip_dst.s_addr) 421 return (0); 422 423 if (IN6_IS_ADDR_6TO4(&addr6)) { 424 /* 425 * 6to4 (RFC 3056). 426 * Check if IPv4 src matches the IPv4 address derived 427 * from the local 6to4 address masked by prefixmask. 428 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24 429 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24 430 */ 431 memcpy(&sin4mask.sin_addr, GET_V4(&mask6), 432 sizeof(sin4mask.sin_addr)); 433 if ((sin4addr.sin_addr.s_addr & sin4mask.sin_addr.s_addr) != 434 (ip.ip_src.s_addr & sin4mask.sin_addr.s_addr)) 435 return (0); 436 } else { 437 /* 6rd (RFC 5569) */ 438 /* 439 * No restriction on the src address in the case of 440 * 6rd because the stf(4) interface always has a 441 * prefix which covers whole of IPv4 src address 442 * range. So, stf_output() will catch all of 443 * 6rd-capsuled IPv4 traffic with suspicious inner dst 444 * IPv4 address (i.e. the IPv6 destination address is 445 * one the admin does not like to route to outside), 446 * and then it discard them silently. 447 */ 448 } 449 450 SDT_PROBE0(if_stf, , encapcheck, accept); 451 452 /* stf interface makes single side match only */ 453 return (32); 454 } 455 456 static int 457 stf_getsrcifa6(struct ifnet *ifp, struct in6_addr *addr, struct in6_addr *mask) 458 { 459 struct ifaddr *ia; 460 struct in_ifaddr *ia4; 461 struct in6_addr addr6, mask6; 462 struct sockaddr_in sin4; 463 struct stf_softc *sc; 464 struct in_addr in; 465 466 NET_EPOCH_ASSERT(); 467 468 sc = ifp->if_softc; 469 470 SDT_PROBE3(if_stf, , getsrcifa6, in, ifp, addr, mask); 471 472 CK_STAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 473 if (ia->ifa_addr->sa_family != AF_INET6) 474 continue; 475 476 addr6 = *IFA_IN6(ia); 477 mask6 = *IFA_MASKIN6(ia); 478 if (sc->srcv4_addr != INADDR_ANY) 479 bcopy(&sc->srcv4_addr, &in, sizeof(in)); 480 else { 481 if (stf_getin4addr(sc, &sin4, addr6, mask6) == NULL) 482 continue; 483 bcopy(&sin4.sin_addr, &in, sizeof(in)); 484 } 485 486 CK_LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash) 487 if (ia4->ia_addr.sin_addr.s_addr == in.s_addr) 488 break; 489 if (ia4 == NULL) 490 continue; 491 492 *addr = addr6; 493 *mask = mask6; 494 495 SDT_PROBE2(if_stf, , getsrcifa6, found, addr, mask); 496 497 return (0); 498 } 499 500 SDT_PROBE0(if_stf, , getsrcifa6, notfound); 501 502 return (ENOENT); 503 } 504 505 static int 506 stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 507 struct route *ro) 508 { 509 struct stf_softc *sc; 510 const struct sockaddr_in6 *dst6; 511 struct sockaddr_in dst4, src4; 512 u_int8_t tos; 513 struct ip *ip; 514 struct ip6_hdr *ip6; 515 struct in6_addr addr6, mask6; 516 int error; 517 518 SDT_PROBE4(if_stf, , stf_output, in, ifp, m, dst, ro); 519 520 #ifdef MAC 521 error = mac_ifnet_check_transmit(ifp, m); 522 if (error) { 523 m_freem(m); 524 SDT_PROBE2(if_stf, , stf_output, error, error, __LINE__); 525 return (error); 526 } 527 #endif 528 529 sc = ifp->if_softc; 530 dst6 = (const struct sockaddr_in6 *)dst; 531 532 /* just in case */ 533 if ((ifp->if_flags & IFF_UP) == 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 /* 541 * If we don't have an ip4 address that match my inner ip6 address, 542 * we shouldn't generate output. Without this check, we'll end up 543 * using wrong IPv4 source. 544 */ 545 if (stf_getsrcifa6(ifp, &addr6, &mask6) != 0) { 546 m_freem(m); 547 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 548 SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__); 549 return (ENETDOWN); 550 } 551 552 if (m->m_len < sizeof(*ip6)) { 553 m = m_pullup(m, sizeof(*ip6)); 554 if (!m) { 555 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 556 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, 557 __LINE__); 558 return (ENOBUFS); 559 } 560 } 561 ip6 = mtod(m, struct ip6_hdr *); 562 tos = IPV6_TRAFFIC_CLASS(ip6); 563 564 /* 565 * Pickup the right outer dst addr from the list of candidates. 566 * ip6_dst has priority as it may be able to give us shorter IPv4 hops. 567 */ 568 if (stf_getin4addr_in6(sc, &dst4, addr6, mask6, 569 ip6->ip6_dst) == NULL) { 570 if (sc->braddr != INADDR_ANY) 571 dst4.sin_addr.s_addr = sc->braddr; 572 else if (stf_getin4addr_in6(sc, &dst4, addr6, mask6, 573 dst6->sin6_addr) == NULL) { 574 m_freem(m); 575 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 576 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, 577 __LINE__); 578 return (ENETUNREACH); 579 } 580 } 581 582 if (bpf_peers_present(ifp->if_bpf)) { 583 /* 584 * We need to prepend the address family as 585 * a four byte field. Cons up a dummy header 586 * to pacify bpf. This is safe because bpf 587 * will only read from the mbuf (i.e., it won't 588 * try to free it or keep a pointer a to it). 589 */ 590 u_int af = AF_INET6; 591 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 592 } 593 594 M_PREPEND(m, sizeof(struct ip), M_NOWAIT); 595 if (m == NULL) { 596 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 597 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, __LINE__); 598 return (ENOBUFS); 599 } 600 ip = mtod(m, struct ip *); 601 602 bzero(ip, sizeof(*ip)); 603 604 if (sc->srcv4_addr != INADDR_ANY) 605 src4.sin_addr.s_addr = sc->srcv4_addr; 606 else if (stf_getin4addr(sc, &src4, addr6, mask6) == NULL) { 607 m_freem(m); 608 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); 609 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, __LINE__); 610 return (ENETUNREACH); 611 } 612 bcopy(&src4.sin_addr, &ip->ip_src, sizeof(ip->ip_src)); 613 bcopy(&dst4.sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)); 614 615 ip->ip_p = IPPROTO_IPV6; 616 ip->ip_ttl = ip_stf_ttl; 617 ip->ip_len = htons(m->m_pkthdr.len); 618 if (ifp->if_flags & IFF_LINK1) 619 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos); 620 else 621 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos); 622 623 M_SETFIB(m, sc->sc_fibnum); 624 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); 625 error = ip_output(m, NULL, NULL, 0, NULL, NULL); 626 627 SDT_PROBE1(if_stf, , stf_output, out, error); 628 return (error); 629 } 630 631 static int 632 isrfc1918addr(struct in_addr *in) 633 { 634 /* 635 * returns 1 if private address range: 636 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 637 */ 638 if (stf_permit_rfc1918 == 0 && ( 639 (ntohl(in->s_addr) & 0xff000000) >> 24 == 10 || 640 (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 || 641 (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)) 642 return (1); 643 644 return (0); 645 } 646 647 static int 648 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in, struct ifnet *inifp) 649 { 650 struct in_ifaddr *ia4; 651 652 /* 653 * reject packets with the following address: 654 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8 655 */ 656 if (IN_MULTICAST(ntohl(in->s_addr))) 657 return (-1); 658 switch ((ntohl(in->s_addr) & 0xff000000) >> 24) { 659 case 0: case 127: case 255: 660 return (-1); 661 } 662 663 /* 664 * reject packets with broadcast 665 */ 666 CK_STAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) { 667 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0) 668 continue; 669 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr) { 670 return (-1); 671 } 672 } 673 674 /* 675 * perform ingress filter 676 */ 677 if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) { 678 struct nhop_object *nh; 679 680 NET_EPOCH_ASSERT(); 681 nh = fib4_lookup(sc->sc_fibnum, *in, 0, 0, 0); 682 if (nh == NULL) 683 return (-1); 684 685 if (nh->nh_ifp != inifp) 686 return (-1); 687 } 688 689 return (0); 690 } 691 692 static int 693 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6, struct ifnet *inifp) 694 { 695 SDT_PROBE3(if_stf, , checkaddr6, in, sc, in6, inifp); 696 697 /* 698 * check 6to4 addresses 699 */ 700 if (IN6_IS_ADDR_6TO4(in6)) { 701 struct in_addr in4; 702 int ret; 703 704 bcopy(GET_V4(in6), &in4, sizeof(in4)); 705 ret = stf_checkaddr4(sc, &in4, inifp); 706 SDT_PROBE2(if_stf, , checkaddr6, out, ret, __LINE__); 707 return (ret); 708 } 709 710 /* 711 * reject anything that look suspicious. the test is implemented 712 * in ip6_input too, but we check here as well to 713 * (1) reject bad packets earlier, and 714 * (2) to be safe against future ip6_input change. 715 */ 716 if (IN6_IS_ADDR_V4COMPAT(in6)) { 717 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__); 718 return (-1); 719 } 720 721 if (IN6_IS_ADDR_V4MAPPED(in6)) { 722 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__); 723 return (-1); 724 } 725 726 SDT_PROBE2(if_stf, , checkaddr6, out, 0, __LINE__); 727 return (0); 728 } 729 730 static int 731 in_stf_input(struct mbuf *m, int off, int proto, void *arg) 732 { 733 struct stf_softc *sc = arg; 734 struct ip ip; 735 struct ip6_hdr *ip6; 736 u_int8_t otos, itos; 737 struct ifnet *ifp; 738 struct nhop_object *nh; 739 740 NET_EPOCH_ASSERT(); 741 742 SDT_PROBE3(if_stf, , stf_input, in, m, off, proto); 743 744 if (proto != IPPROTO_IPV6) { 745 m_freem(m); 746 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 747 return (IPPROTO_DONE); 748 } 749 750 m_copydata(m, 0, sizeof(struct ip), (caddr_t)&ip); 751 if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) { 752 m_freem(m); 753 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 754 return (IPPROTO_DONE); 755 } 756 757 ifp = STF2IFP(sc); 758 759 #ifdef MAC 760 mac_ifnet_create_mbuf(ifp, m); 761 #endif 762 763 /* 764 * perform sanity check against outer src/dst. 765 * for source, perform ingress filter as well. 766 */ 767 if (stf_checkaddr4(sc, &ip.ip_dst, NULL) < 0 || 768 stf_checkaddr4(sc, &ip.ip_src, m->m_pkthdr.rcvif) < 0) { 769 m_freem(m); 770 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 771 return (IPPROTO_DONE); 772 } 773 774 otos = ip.ip_tos; 775 m_adj(m, off); 776 777 if (m->m_len < sizeof(*ip6)) { 778 m = m_pullup(m, sizeof(*ip6)); 779 if (!m) { 780 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, 781 __LINE__); 782 return (IPPROTO_DONE); 783 } 784 } 785 ip6 = mtod(m, struct ip6_hdr *); 786 787 /* 788 * perform sanity check against inner src/dst. 789 * for source, perform ingress filter as well. 790 */ 791 if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 || 792 stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) { 793 m_freem(m); 794 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 795 return (IPPROTO_DONE); 796 } 797 798 /* 799 * reject packets with private address range. 800 * (requirement from RFC3056 section 2 1st paragraph) 801 */ 802 if ((IN6_IS_ADDR_6TO4(&ip6->ip6_src) && isrfc1918addr(&ip.ip_src)) || 803 (IN6_IS_ADDR_6TO4(&ip6->ip6_dst) && isrfc1918addr(&ip.ip_dst))) { 804 m_freem(m); 805 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 806 return (IPPROTO_DONE); 807 } 808 809 /* 810 * Ignore if the destination is the same stf interface because 811 * all of valid IPv6 outgoing traffic should go interfaces 812 * except for it. 813 */ 814 nh = fib6_lookup(sc->sc_fibnum, &ip6->ip6_dst, 0, 0, 0); 815 if (nh == NULL) { 816 m_free(m); 817 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 818 return (IPPROTO_DONE); 819 } 820 if ((nh->nh_ifp == ifp) && 821 (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &nh->gw6_sa.sin6_addr))) { 822 m_free(m); 823 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 824 return (IPPROTO_DONE); 825 } 826 827 itos = IPV6_TRAFFIC_CLASS(ip6); 828 if ((ifp->if_flags & IFF_LINK1) != 0) 829 ip_ecn_egress(ECN_ALLOWED, &otos, &itos); 830 else 831 ip_ecn_egress(ECN_NOCARE, &otos, &itos); 832 ip6->ip6_flow &= ~htonl(0xff << 20); 833 ip6->ip6_flow |= htonl((u_int32_t)itos << 20); 834 835 m->m_pkthdr.rcvif = ifp; 836 837 if (bpf_peers_present(ifp->if_bpf)) { 838 /* 839 * We need to prepend the address family as 840 * a four byte field. Cons up a dummy header 841 * to pacify bpf. This is safe because bpf 842 * will only read from the mbuf (i.e., it won't 843 * try to free it or keep a pointer a to it). 844 */ 845 u_int32_t af = AF_INET6; 846 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 847 } 848 849 /* 850 * Put the packet to the network layer input queue according to the 851 * specified address family. 852 * See net/if_gif.c for possible issues with packet processing 853 * reorder due to extra queueing. 854 */ 855 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1); 856 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len); 857 M_SETFIB(m, ifp->if_fib); 858 netisr_dispatch(NETISR_IPV6, m); 859 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__); 860 return (IPPROTO_DONE); 861 } 862 863 static struct sockaddr_in * 864 stf_getin4addr_in6(struct stf_softc *sc, struct sockaddr_in *sin, 865 struct in6_addr addr6, struct in6_addr mask6, struct in6_addr in6) 866 { 867 int i; 868 struct sockaddr_in *out; 869 870 /* 871 * When (src addr & src mask) != (in6 & src mask), 872 * the dst is not in the 6rd domain. The IPv4 address must 873 * not be used. 874 */ 875 for (i = 0; i < sizeof(addr6); i++) { 876 if ((((u_char *)&addr6)[i] & ((u_char *)&mask6)[i]) != 877 (((u_char *)&in6)[i] & ((u_char *)&mask6)[i])) { 878 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, 879 &mask6, &in6, NULL); 880 return (NULL); 881 } 882 } 883 884 /* After the mask check, use in6 instead of addr6. */ 885 out = stf_getin4addr(sc, sin, in6, mask6); 886 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, &mask6, &in6, out); 887 return (out); 888 } 889 890 static struct sockaddr_in * 891 stf_getin4addr(struct stf_softc *sc, struct sockaddr_in *sin, 892 struct in6_addr addr6, struct in6_addr mask6) 893 { 894 struct in_addr *in; 895 896 SDT_PROBE2(if_stf, , getin4addr, in, &addr6, &mask6); 897 898 memset(sin, 0, sizeof(*sin)); 899 in = &sin->sin_addr; 900 if (IN6_IS_ADDR_6TO4(&addr6)) { 901 /* 6to4 (RFC 3056) */ 902 bcopy(GET_V4(&addr6), in, sizeof(*in)); 903 if (isrfc1918addr(in)) 904 return (NULL); 905 } else { 906 /* 6rd (RFC 5569) */ 907 in_addr_t v4prefix; 908 uint8_t *v6 = (uint8_t*)&addr6; 909 uint64_t v6prefix; 910 u_int plen; 911 u_int v4suffixlen; 912 913 v4prefix = 0; 914 if (sc->v4prefixlen < 32) { 915 v4suffixlen = 32 - sc->v4prefixlen; 916 v4prefix = ntohl(sc->srcv4_addr) & 917 (0xffffffffU << v4suffixlen); 918 } else { 919 MPASS(sc->v4prefixlen == 32); 920 v4suffixlen = 32; 921 } 922 923 plen = in6_mask2len(&mask6, NULL); 924 if (plen > 64) 925 return (NULL); 926 927 /* To make this simple we do not support prefixes longer than 928 * 64 bits. RFC5969 says "a 6rd delegated prefix SHOULD be /64 929 * or shorter." so this is a moderately safe assumption. */ 930 v6prefix = be64toh(*(uint64_t *)v6); 931 932 /* Shift away the v6 prefix itself. */ 933 v6prefix <<= plen; 934 v6prefix >>= plen; 935 936 /* Now shift away everything after the v4 address. */ 937 v6prefix >>= 64 - plen - v4suffixlen; 938 939 sin->sin_addr.s_addr = htonl(v4prefix | (uint32_t)v6prefix); 940 } 941 942 SDT_PROBE1(if_stf, , getin4addr, out, sin); 943 944 return (sin); 945 } 946 947 static int 948 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 949 { 950 struct ifaddr *ifa; 951 struct ifdrv *ifd; 952 struct ifreq *ifr; 953 struct sockaddr_in sin4; 954 struct stf_softc *sc_cur; 955 struct stfv4args args; 956 int error, mtu; 957 958 error = 0; 959 sc_cur = ifp->if_softc; 960 961 switch (cmd) { 962 case SIOCSDRVSPEC: 963 ifd = (struct ifdrv *)data; 964 error = priv_check(curthread, PRIV_NET_ADDIFADDR); 965 if (error) 966 break; 967 if (ifd->ifd_cmd == STF6RD_SV4NET) { 968 if (ifd->ifd_len != sizeof(args)) { 969 error = EINVAL; 970 break; 971 } 972 bzero(&args, sizeof(args)); 973 error = copyin(ifd->ifd_data, &args, ifd->ifd_len); 974 if (error) 975 break; 976 977 if (args.v4_prefixlen < 1 || args.v4_prefixlen > 32) { 978 error = EINVAL; 979 break; 980 } 981 982 bcopy(&args.srcv4_addr, &sc_cur->srcv4_addr, 983 sizeof(sc_cur->srcv4_addr)); 984 sc_cur->v4prefixlen = args.v4_prefixlen; 985 SDT_PROBE3(if_stf, , ioctl, sv4net, sc_cur->srcv4_addr, 986 sc_cur->srcv4_addr, sc_cur->v4prefixlen); 987 } else if (ifd->ifd_cmd == STF6RD_SBR) { 988 if (ifd->ifd_len != sizeof(args)) { 989 error = EINVAL; 990 break; 991 } 992 bzero(&args, sizeof(args)); 993 error = copyin(ifd->ifd_data, &args, ifd->ifd_len); 994 if (error) 995 break; 996 sc_cur->braddr = args.braddr.s_addr; 997 SDT_PROBE1(if_stf, , ioctl, sdstv4, 998 sc_cur->braddr); 999 } else 1000 error = EINVAL; 1001 break; 1002 case SIOCGDRVSPEC: 1003 ifd = (struct ifdrv *)data; 1004 if (ifd->ifd_cmd != STF6RD_GV4NET) { 1005 error = EINVAL; 1006 break; 1007 } 1008 if (ifd->ifd_len != sizeof(args)) { 1009 error = EINVAL; 1010 break; 1011 } 1012 bzero(&args, sizeof(args)); 1013 args.srcv4_addr.s_addr = sc_cur->srcv4_addr; 1014 args.braddr.s_addr = sc_cur->braddr; 1015 args.v4_prefixlen = sc_cur->v4prefixlen; 1016 error = copyout(&args, ifd->ifd_data, ifd->ifd_len); 1017 break; 1018 case SIOCSIFADDR: 1019 ifa = (struct ifaddr *)data; 1020 SDT_PROBE1(if_stf, , ioctl, ifaddr, ifa); 1021 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) { 1022 error = EAFNOSUPPORT; 1023 break; 1024 } 1025 if (stf_getin4addr(sc_cur, &sin4, 1026 satosin6(ifa->ifa_addr)->sin6_addr, 1027 satosin6(ifa->ifa_netmask)->sin6_addr) == NULL) { 1028 error = EINVAL; 1029 break; 1030 } 1031 ifp->if_flags |= IFF_UP; 1032 ifp->if_drv_flags |= IFF_DRV_RUNNING; 1033 break; 1034 1035 case SIOCADDMULTI: 1036 case SIOCDELMULTI: 1037 ifr = (struct ifreq *)data; 1038 if (ifr && ifr->ifr_addr.sa_family == AF_INET6) 1039 ; 1040 else 1041 error = EAFNOSUPPORT; 1042 break; 1043 1044 case SIOCGIFMTU: 1045 break; 1046 1047 case SIOCSIFMTU: 1048 ifr = (struct ifreq *)data; 1049 mtu = ifr->ifr_mtu; 1050 /* RFC 4213 3.2 ideal world MTU */ 1051 if (mtu < IPV6_MINMTU || mtu > IF_MAXMTU - 20) 1052 return (EINVAL); 1053 ifp->if_mtu = mtu; 1054 break; 1055 1056 default: 1057 error = EINVAL; 1058 break; 1059 } 1060 1061 return (error); 1062 } 1063