in6_l2tp.c revision 1.14
1 /* $NetBSD: in6_l2tp.c,v 1.14 2018/01/26 07:49:15 maxv 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 1.14 2018/01/26 07:49:15 maxv 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 /* 271 * L2TPv3 control packet received. 272 * userland daemon(l2tpd?) should process. 273 */ 274 return rip6_input(mp, offp, proto); 275 } 276 277 var = l2tp_lookup_session_ref(sess_id, &psref); 278 if (var == NULL) { 279 m_freem(m); 280 IP_STATINC(IP_STAT_NOL2TP); 281 return IPPROTO_DONE; 282 } 283 284 sc = var->lv_softc; 285 l2tpp = &(sc->l2tp_ec.ec_if); 286 287 if (l2tpp == NULL || (l2tpp->if_flags & IFF_UP) == 0) { 288 #ifdef L2TP_DEBUG 289 if (l2tpp == NULL) 290 log(LOG_DEBUG, "%s: l2tpp is NULL\n", __func__); 291 else 292 log(LOG_DEBUG, "%s: l2tpp is down\n", __func__); 293 #endif 294 m_freem(m); 295 IP_STATINC(IP_STAT_NOL2TP); 296 goto out; 297 } 298 299 /* other CPU did l2tp_delete_tunnel */ 300 if (var->lv_psrc == NULL || var->lv_pdst == NULL) { 301 m_freem(m); 302 ip_statinc(IP_STAT_NOL2TP); 303 goto out; 304 } 305 306 if (var->lv_state != L2TP_STATE_UP) { 307 m_freem(m); 308 goto out; 309 } 310 m_adj(m, off + sizeof(uint32_t)); 311 312 if (var->lv_use_cookie == L2TP_COOKIE_ON) { 313 if (m->m_pkthdr.len < var->lv_my_cookie_len) { 314 m_freem(m); 315 goto out; 316 } 317 if (var->lv_my_cookie_len == 4) { 318 m_copydata(m, 0, sizeof(uint32_t), (void *)&cookie_32); 319 NTOHL(cookie_32); 320 if (cookie_32 != var->lv_my_cookie) { 321 m_freem(m); 322 goto out; 323 } 324 m_adj(m, sizeof(uint32_t)); 325 } else { 326 m_copydata(m, 0, sizeof(uint64_t), (void *)&cookie_64); 327 BE64TOH(cookie_64); 328 if (cookie_64 != var->lv_my_cookie) { 329 m_freem(m); 330 goto out; 331 } 332 m_adj(m, sizeof(uint64_t)); 333 } 334 } 335 336 /* TODO: IP_TCPMSS support */ 337 #ifdef IP_TCPMSS 338 m = l2tp_tcpmss_clamp(l2tpp, m); 339 if (m == NULL) 340 goto out; 341 #endif 342 l2tp_input(m, l2tpp); 343 344 out: 345 l2tp_putref_variant(var, &psref); 346 return IPPROTO_DONE; 347 } 348 349 /* 350 * This function is used by encap6_lookup() to decide priority of the encaptab. 351 * This priority is compared to the match length between mbuf's source/destination 352 * IPv6 address pair and encaptab's one. 353 * l2tp(4) does not use address pairs to search matched encaptab, so this 354 * function must return the length bigger than or equals to IPv6 address pair to 355 * avoid wrong encaptab. 356 */ 357 static int 358 in6_l2tp_match(struct mbuf *m, int off, int proto, void *arg) 359 { 360 struct l2tp_variant *var = arg; 361 uint32_t sess_id; 362 363 KASSERT(proto == IPPROTO_L2TP); 364 365 /* 366 * If the packet contains no session ID it cannot match 367 */ 368 if (m_length(m) < off + sizeof(uint32_t)) 369 return 0; 370 371 /* get L2TP session ID */ 372 m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id); 373 NTOHL(sess_id); 374 if (sess_id == 0) { 375 /* 376 * L2TPv3 control packet received. 377 * userland daemon(l2tpd?) should process. 378 */ 379 return 128 * 2; 380 } else if (sess_id == var->lv_my_sess_id) 381 return 128 * 2; 382 else 383 return 0; 384 } 385 386 int 387 in6_l2tp_attach(struct l2tp_variant *var) 388 { 389 390 var->lv_encap_cookie = encap_attach_func(AF_INET6, IPPROTO_L2TP, 391 in6_l2tp_match, &in6_l2tp_encapsw, var); 392 if (var->lv_encap_cookie == NULL) 393 return EEXIST; 394 395 return 0; 396 } 397 398 int 399 in6_l2tp_detach(struct l2tp_variant *var) 400 { 401 int error; 402 403 error = encap_detach(var->lv_encap_cookie); 404 if (error == 0) 405 var->lv_encap_cookie = NULL; 406 407 return error; 408 } 409
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