in6_l2tp.c revision 1.17
1 /* $NetBSD: in6_l2tp.c,v 1.17 2018/09/03 02:33:31 knakahara Exp $ */ 2 3 /* 4 * Copyright (c) 2017 Internet Initiative Japan Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: in6_l2tp.c,v 1.17 2018/09/03 02:33:31 knakahara Exp $"); 31 32 #ifdef _KERNEL_OPT 33 #include "opt_l2tp.h" 34 #endif 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/socket.h> 39 #include <sys/sockio.h> 40 #include <sys/mbuf.h> 41 #include <sys/errno.h> 42 #include <sys/ioctl.h> 43 #include <sys/syslog.h> 44 #include <sys/kernel.h> 45 46 #include <net/if.h> 47 #include <net/route.h> 48 #include <net/if_ether.h> 49 50 #include <netinet/in.h> 51 #include <netinet/in_systm.h> 52 #include <netinet/ip.h> 53 #include <netinet/ip_var.h> 54 #include <netinet/ip_private.h> 55 #include <netinet/in_l2tp.h> 56 #include <netinet/in_var.h> 57 #include <netinet/ip_encap.h> 58 59 #include <netinet/ip6.h> 60 #include <netinet6/ip6_var.h> 61 #include <netinet6/in6_l2tp.h> 62 63 #ifdef ALTQ 64 #include <altq/altq.h> 65 #endif 66 67 /* TODO: IP_TCPMSS support */ 68 #undef IP_TCPMSS 69 #ifdef IP_TCPMSS 70 #include <netinet/ip_tcpmss.h> 71 #endif 72 73 #include <net/if_l2tp.h> 74 75 #define L2TP_HLIM6 64 76 int ip6_l2tp_hlim = L2TP_HLIM6; 77 78 static int in6_l2tp_input(struct mbuf **, int *, int, void *); 79 80 static const struct encapsw in6_l2tp_encapsw = { 81 .encapsw6 = { 82 .pr_input = in6_l2tp_input, 83 .pr_ctlinput = NULL, 84 } 85 }; 86 87 static int in6_l2tp_match(struct mbuf *, int, int, void *); 88 89 int 90 in6_l2tp_output(struct l2tp_variant *var, struct mbuf *m) 91 { 92 struct rtentry *rt; 93 struct l2tp_ro *lro; 94 struct l2tp_softc *sc; 95 struct ifnet *ifp; 96 struct sockaddr_in6 *sin6_src = satosin6(var->lv_psrc); 97 struct sockaddr_in6 *sin6_dst = satosin6(var->lv_pdst); 98 struct ip6_hdr ip6hdr; /* capsule IP header, host byte ordered */ 99 int error; 100 uint32_t sess_id; 101 102 KASSERT(var != NULL); 103 KASSERT(l2tp_heldref_variant(var)); 104 KASSERT(sin6_src != NULL && sin6_dst != NULL); 105 KASSERT(sin6_src->sin6_family == AF_INET6 106 && sin6_dst->sin6_family == AF_INET6); 107 108 sc = var->lv_softc; 109 ifp = &sc->l2tp_ec.ec_if; 110 error = l2tp_check_nesting(ifp, m); 111 if (error) { 112 m_freem(m); 113 goto looped; 114 } 115 116 /* bidirectional configured tunnel mode */ 117 if (IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr)) { 118 m_freem(m); 119 if ((ifp->if_flags & IFF_DEBUG) != 0) 120 log(LOG_DEBUG, "%s: ENETUNREACH\n", __func__); 121 return ENETUNREACH; 122 } 123 124 #ifdef NOTYET 125 /* TODO: support ALTQ for innner frame */ 126 #ifdef ALTQ 127 ALTQ_SAVE_PAYLOAD(m, AF_ETHER); 128 #endif 129 #endif 130 131 memset(&ip6hdr, 0, sizeof(ip6hdr)); 132 ip6hdr.ip6_src = sin6_src->sin6_addr; 133 ip6hdr.ip6_dst = sin6_dst->sin6_addr; 134 /* unlike IPv4, IP version must be filled by caller of ip6_output() */ 135 ip6hdr.ip6_vfc = 0x60; 136 ip6hdr.ip6_nxt = IPPROTO_L2TP; 137 ip6hdr.ip6_hlim = ip6_l2tp_hlim; 138 /* outer IP payload length */ 139 ip6hdr.ip6_plen = 0; 140 /* session-id length */ 141 ip6hdr.ip6_plen += sizeof(uint32_t); 142 if (var->lv_use_cookie == L2TP_COOKIE_ON) { 143 /* cookie length */ 144 ip6hdr.ip6_plen += var->lv_peer_cookie_len; 145 } 146 147 /* TODO: IP_TCPMSS support */ 148 #ifdef IP_TCPMSS 149 m = l2tp_tcpmss_clamp(ifp, m); 150 if (m == NULL) 151 return EINVAL; 152 #endif 153 154 /* 155 * Payload length. 156 * 157 * NOTE: payload length may be changed in ip_tcpmss(). Typical case 158 * is missing of TCP mss option in original TCP header. 159 */ 160 ip6hdr.ip6_plen += m->m_pkthdr.len; 161 HTONS(ip6hdr.ip6_plen); 162 163 if (var->lv_use_cookie == L2TP_COOKIE_ON) { 164 /* prepend session cookie */ 165 uint32_t cookie_32; 166 uint64_t cookie_64; 167 M_PREPEND(m, var->lv_peer_cookie_len, M_DONTWAIT); 168 if (m && m->m_len < var->lv_peer_cookie_len) 169 m = m_pullup(m, var->lv_peer_cookie_len); 170 if (m == NULL) 171 return ENOBUFS; 172 if (var->lv_peer_cookie_len == 4) { 173 cookie_32 = htonl((uint32_t)var->lv_peer_cookie); 174 memcpy(mtod(m, void *), &cookie_32, sizeof(uint32_t)); 175 } else { 176 cookie_64 = htobe64(var->lv_peer_cookie); 177 memcpy(mtod(m, void *), &cookie_64, sizeof(uint64_t)); 178 } 179 } 180 181 /* prepend session-ID */ 182 sess_id = htonl(var->lv_peer_sess_id); 183 M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT); 184 if (m && m->m_len < sizeof(uint32_t)) 185 m = m_pullup(m, sizeof(uint32_t)); 186 if (m == NULL) 187 return ENOBUFS; 188 memcpy(mtod(m, uint32_t *), &sess_id, sizeof(uint32_t)); 189 190 /* prepend new IP header */ 191 M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT); 192 if (m == NULL) 193 return ENOBUFS; 194 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 195 m = m_copyup(m, sizeof(struct ip), 0); 196 } else { 197 if (m->m_len < sizeof(struct ip6_hdr)) 198 m = m_pullup(m, sizeof(struct ip6_hdr)); 199 } 200 if (m == NULL) 201 return ENOBUFS; 202 memcpy(mtod(m, struct ip6_hdr *), &ip6hdr, sizeof(struct ip6_hdr)); 203 204 lro = percpu_getref(sc->l2tp_ro_percpu); 205 mutex_enter(lro->lr_lock); 206 if ((rt = rtcache_lookup(&lro->lr_ro, var->lv_pdst)) == NULL) { 207 mutex_exit(lro->lr_lock); 208 percpu_putref(sc->l2tp_ro_percpu); 209 m_freem(m); 210 return ENETUNREACH; 211 } 212 213 /* If the route constitutes infinite encapsulation, punt. */ 214 if (rt->rt_ifp == ifp) { 215 rtcache_unref(rt, &lro->lr_ro); 216 rtcache_free(&lro->lr_ro); 217 mutex_exit(lro->lr_lock); 218 percpu_putref(sc->l2tp_ro_percpu); 219 m_freem(m); 220 return ENETUNREACH; /* XXX */ 221 } 222 rtcache_unref(rt, &lro->lr_ro); 223 224 /* 225 * To avoid inappropriate rewrite of checksum, 226 * clear csum flags. 227 */ 228 m->m_pkthdr.csum_flags = 0; 229 230 error = ip6_output(m, 0, &lro->lr_ro, 0, NULL, NULL, NULL); 231 mutex_exit(lro->lr_lock); 232 percpu_putref(sc->l2tp_ro_percpu); 233 return(error); 234 235 looped: 236 if (error) 237 ifp->if_oerrors++; 238 239 return error; 240 } 241 242 static int 243 in6_l2tp_input(struct mbuf **mp, int *offp, int proto, void *eparg __unused) 244 { 245 struct mbuf *m = *mp; 246 int off = *offp; 247 248 struct ifnet *l2tpp = NULL; 249 struct l2tp_softc *sc; 250 struct l2tp_variant *var; 251 uint32_t sess_id; 252 uint32_t cookie_32; 253 uint64_t cookie_64; 254 struct psref psref; 255 256 KASSERT((m->m_flags & M_PKTHDR) != 0); 257 258 if (m->m_pkthdr.len < off + sizeof(uint32_t)) { 259 m_freem(m); 260 return IPPROTO_DONE; 261 } 262 263 /* get L2TP session ID */ 264 m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id); 265 NTOHL(sess_id); 266 #ifdef L2TP_DEBUG 267 log(LOG_DEBUG, "%s: sess_id = %" PRIu32 "\n", __func__, sess_id); 268 #endif 269 if (sess_id == 0) { 270 int rv; 271 /* 272 * L2TPv3 control packet received. 273 * userland daemon(l2tpd?) should process. 274 */ 275 SOFTNET_LOCK_IF_NET_MPSAFE(); 276 rv = rip6_input(mp, offp, proto); 277 SOFTNET_UNLOCK_IF_NET_MPSAFE(); 278 return rv; 279 } 280 281 var = l2tp_lookup_session_ref(sess_id, &psref); 282 if (var == NULL) { 283 m_freem(m); 284 IP_STATINC(IP_STAT_NOL2TP); 285 return IPPROTO_DONE; 286 } 287 288 sc = var->lv_softc; 289 l2tpp = &(sc->l2tp_ec.ec_if); 290 291 if (l2tpp == NULL || (l2tpp->if_flags & IFF_UP) == 0) { 292 #ifdef L2TP_DEBUG 293 if (l2tpp == NULL) 294 log(LOG_DEBUG, "%s: l2tpp is NULL\n", __func__); 295 else 296 log(LOG_DEBUG, "%s: l2tpp is down\n", __func__); 297 #endif 298 m_freem(m); 299 IP_STATINC(IP_STAT_NOL2TP); 300 goto out; 301 } 302 303 /* other CPU did l2tp_delete_tunnel */ 304 if (var->lv_psrc == NULL || var->lv_pdst == NULL) { 305 m_freem(m); 306 ip_statinc(IP_STAT_NOL2TP); 307 goto out; 308 } 309 310 if (var->lv_state != L2TP_STATE_UP) { 311 m_freem(m); 312 goto out; 313 } 314 m_adj(m, off + sizeof(uint32_t)); 315 316 if (var->lv_use_cookie == L2TP_COOKIE_ON) { 317 if (m->m_pkthdr.len < var->lv_my_cookie_len) { 318 m_freem(m); 319 goto out; 320 } 321 if (var->lv_my_cookie_len == 4) { 322 m_copydata(m, 0, sizeof(uint32_t), (void *)&cookie_32); 323 NTOHL(cookie_32); 324 if (cookie_32 != var->lv_my_cookie) { 325 m_freem(m); 326 goto out; 327 } 328 m_adj(m, sizeof(uint32_t)); 329 } else { 330 m_copydata(m, 0, sizeof(uint64_t), (void *)&cookie_64); 331 BE64TOH(cookie_64); 332 if (cookie_64 != var->lv_my_cookie) { 333 m_freem(m); 334 goto out; 335 } 336 m_adj(m, sizeof(uint64_t)); 337 } 338 } 339 340 /* TODO: IP_TCPMSS support */ 341 #ifdef IP_TCPMSS 342 m = l2tp_tcpmss_clamp(l2tpp, m); 343 if (m == NULL) 344 goto out; 345 #endif 346 l2tp_input(m, l2tpp); 347 348 out: 349 l2tp_putref_variant(var, &psref); 350 return IPPROTO_DONE; 351 } 352 353 /* 354 * This function is used by encap6_lookup() to decide priority of the encaptab. 355 * This priority is compared to the match length between mbuf's source/destination 356 * IPv6 address pair and encaptab's one. 357 * l2tp(4) does not use address pairs to search matched encaptab, so this 358 * function must return the length bigger than or equals to IPv6 address pair to 359 * avoid wrong encaptab. 360 */ 361 static int 362 in6_l2tp_match(struct mbuf *m, int off, int proto, void *arg) 363 { 364 struct l2tp_softc *sc = arg; 365 struct l2tp_variant *var; 366 struct psref psref; 367 uint32_t sess_id; 368 int rv = 0; 369 370 KASSERT(proto == IPPROTO_L2TP); 371 372 var = l2tp_getref_variant(sc, &psref); 373 if (__predict_false(var == NULL)) 374 return rv; 375 376 /* 377 * If the packet contains no session ID it cannot match 378 */ 379 if (m_length(m) < off + sizeof(uint32_t)) { 380 rv = 0 ; 381 goto out; 382 } 383 384 /* get L2TP session ID */ 385 m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id); 386 NTOHL(sess_id); 387 if (sess_id == 0) { 388 /* 389 * L2TPv3 control packet received. 390 * userland daemon(l2tpd?) should process. 391 */ 392 rv = 128 * 2; 393 } else if (sess_id == var->lv_my_sess_id) 394 rv = 128 * 2; 395 else 396 rv = 0; 397 398 out: 399 l2tp_putref_variant(var, &psref); 400 return rv; 401 } 402 403 int 404 in6_l2tp_attach(struct l2tp_variant *var) 405 { 406 struct l2tp_softc *sc = var->lv_softc; 407 408 if (sc == NULL) 409 return EINVAL; 410 var->lv_encap_cookie = encap_attach_func(AF_INET6, IPPROTO_L2TP, 411 in6_l2tp_match, &in6_l2tp_encapsw, sc); 412 if (var->lv_encap_cookie == NULL) 413 return EEXIST; 414 415 return 0; 416 } 417 418 int 419 in6_l2tp_detach(struct l2tp_variant *var) 420 { 421 int error; 422 423 error = encap_detach(var->lv_encap_cookie); 424 if (error == 0) 425 var->lv_encap_cookie = NULL; 426 427 return error; 428 } 429
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