in6_l2tp.c revision 1.5.4.2
1 /* $NetBSD: in6_l2tp.c,v 1.5.4.2 2017/04/21 16:54:06 bouyer 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 1.5.4.2 2017/04/21 16:54:06 bouyer 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); 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 goto looped; 113 114 #ifdef NOTYET 115 /* TODO: support ALTQ for innner frame */ 116 #ifdef ALTQ 117 ALTQ_SAVE_PAYLOAD(m, AF_ETHER); 118 #endif 119 #endif 120 121 memset(&ip6hdr, 0, sizeof(ip6hdr)); 122 ip6hdr.ip6_src = sin6_src->sin6_addr; 123 /* bidirectional configured tunnel mode */ 124 if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr)) 125 ip6hdr.ip6_dst = sin6_dst->sin6_addr; 126 else { 127 m_freem(m); 128 if ((ifp->if_flags & IFF_DEBUG) != 0) 129 log(LOG_DEBUG, "%s: ENETUNREACH\n", __func__); 130 return ENETUNREACH; 131 } 132 /* unlike IPv4, IP version must be filled by caller of ip6_output() */ 133 ip6hdr.ip6_vfc = 0x60; 134 ip6hdr.ip6_nxt = IPPROTO_L2TP; 135 ip6hdr.ip6_hlim = ip6_l2tp_hlim; 136 /* outer IP payload length */ 137 ip6hdr.ip6_plen = 0; 138 /* session-id length */ 139 ip6hdr.ip6_plen += sizeof(uint32_t); 140 if (var->lv_use_cookie == L2TP_COOKIE_ON) { 141 /* cookie length */ 142 ip6hdr.ip6_plen += var->lv_peer_cookie_len; 143 } 144 145 /* TODO: IP_TCPMSS support */ 146 #ifdef IP_TCPMSS 147 m = l2tp_tcpmss_clamp(ifp, m); 148 if (m == NULL) 149 return EINVAL; 150 #endif 151 152 /* 153 * payload length 154 * NOTE: Payload length may be changed in ip_tcpmss(). 155 * Typical case is missing of TCP mss option in original 156 * TCP header. 157 */ 158 ip6hdr.ip6_plen += m->m_pkthdr.len; 159 HTONS(ip6hdr.ip6_plen); 160 161 if (var->lv_use_cookie == L2TP_COOKIE_ON) { 162 /* prepend session cookie */ 163 uint32_t cookie_32; 164 uint64_t cookie_64; 165 M_PREPEND(m, var->lv_peer_cookie_len, M_DONTWAIT); 166 if (m && m->m_len < var->lv_peer_cookie_len) 167 m = m_pullup(m, var->lv_peer_cookie_len); 168 if (m == NULL) 169 return ENOBUFS; 170 if (var->lv_peer_cookie_len == 4) { 171 cookie_32 = htonl((uint32_t)var->lv_peer_cookie); 172 memcpy(mtod(m, void *), &cookie_32, 173 sizeof(uint32_t)); 174 } else { 175 cookie_64 = htobe64(var->lv_peer_cookie); 176 memcpy(mtod(m, void *), &cookie_64, 177 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 (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 193 if (m) 194 m = m_copyup(m, sizeof(struct ip), 0); 195 } else { 196 if (m && m->m_len < sizeof(struct ip6_hdr)) 197 m = m_pullup(m, sizeof(struct ip6_hdr)); 198 } 199 if (m == NULL) 200 return ENOBUFS; 201 memcpy(mtod(m, struct ip6_hdr *), &ip6hdr, sizeof(struct ip6_hdr)); 202 203 lro = percpu_getref(sc->l2tp_ro_percpu); 204 mutex_enter(&lro->lr_lock); 205 if ((rt = rtcache_lookup(&lro->lr_ro, var->lv_pdst)) == NULL) { 206 mutex_exit(&lro->lr_lock); 207 percpu_putref(sc->l2tp_ro_percpu); 208 m_freem(m); 209 return ENETUNREACH; 210 } 211 212 /* If the route constitutes infinite encapsulation, punt. */ 213 if (rt->rt_ifp == ifp) { 214 rtcache_unref(rt, &lro->lr_ro); 215 rtcache_free(&lro->lr_ro); 216 mutex_exit(&lro->lr_lock); 217 percpu_putref(sc->l2tp_ro_percpu); 218 m_freem(m); 219 return ENETUNREACH; /* XXX */ 220 } 221 rtcache_unref(rt, &lro->lr_ro); 222 223 /* 224 * To avoid inappropriate rewrite of checksum, 225 * clear csum flags. 226 */ 227 m->m_pkthdr.csum_flags = 0; 228 229 error = ip6_output(m, 0, &lro->lr_ro, 0, NULL, NULL, NULL); 230 mutex_exit(&lro->lr_lock); 231 percpu_putref(sc->l2tp_ro_percpu); 232 return(error); 233 234 looped: 235 if (error) 236 ifp->if_oerrors++; 237 238 return error; 239 } 240 241 static int 242 in6_l2tp_input(struct mbuf **mp, int *offp, int proto) 243 { 244 struct mbuf *m = *mp; 245 int off = *offp; 246 247 struct ifnet *l2tpp = NULL; 248 struct l2tp_softc *sc; 249 struct l2tp_variant *var; 250 uint32_t sess_id; 251 uint32_t cookie_32; 252 uint64_t cookie_64; 253 struct psref psref; 254 255 if (m->m_len < off + sizeof(uint32_t)) { 256 m = m_pullup(m, off + sizeof(uint32_t)); 257 if (!m) { 258 /* if payload length < 4 octets */ 259 return IPPROTO_DONE; 260 } 261 *mp = m; 262 } 263 264 /* get L2TP session ID */ 265 m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id); 266 NTOHL(sess_id); 267 #ifdef L2TP_DEBUG 268 log(LOG_DEBUG, "%s: sess_id = %" PRIu32 "\n", __func__, sess_id); 269 #endif 270 if (sess_id == 0) { 271 /* 272 * L2TPv3 control packet received. 273 * userland daemon(l2tpd?) should process. 274 */ 275 return rip6_input(mp, offp, proto); 276 } 277 278 var = l2tp_lookup_session_ref(sess_id, &psref); 279 if (var == NULL) { 280 m_freem(m); 281 IP_STATINC(IP_STAT_NOL2TP); 282 return IPPROTO_DONE; 283 } else { 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 /* other CPU do l2tp_delete_tunnel */ 299 if (var->lv_psrc == NULL || var->lv_pdst == NULL) { 300 m_freem(m); 301 ip_statinc(IP_STAT_NOL2TP); 302 goto out; 303 } 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 (var->lv_my_cookie_len == 4) { 314 m_copydata(m, 0, sizeof(uint32_t), (void *)&cookie_32); 315 NTOHL(cookie_32); 316 if (cookie_32 != var->lv_my_cookie) { 317 m_freem(m); 318 goto out; 319 } 320 m_adj(m, sizeof(uint32_t)); 321 } else { 322 m_copydata(m, 0, sizeof(uint64_t), (void *)&cookie_64); 323 BE64TOH(cookie_64); 324 if (cookie_64 != var->lv_my_cookie) { 325 m_freem(m); 326 goto out; 327 } 328 m_adj(m, sizeof(uint64_t)); 329 } 330 } 331 332 /* TODO: IP_TCPMSS support */ 333 #ifdef IP_TCPMSS 334 m = l2tp_tcpmss_clamp(l2tpp, m); 335 if (m == NULL) 336 goto out; 337 #endif 338 l2tp_input(m, l2tpp); 339 340 out: 341 l2tp_putref_variant(var, &psref); 342 return IPPROTO_DONE; 343 } 344 345 /* 346 * This function is used by encap6_lookup() to decide priority of the encaptab. 347 * This priority is compared to the match length between mbuf's source/destination 348 * IPv6 address pair and encaptab's one. 349 * l2tp(4) does not use address pairs to search matched encaptab, so this 350 * function must return the length bigger than or equals to IPv6 address pair to 351 * avoid wrong encaptab. 352 */ 353 static int 354 in6_l2tp_match(struct mbuf *m, int off, int proto, void *arg) 355 { 356 struct l2tp_variant *var = arg; 357 uint32_t sess_id; 358 359 KASSERT(proto == IPPROTO_L2TP); 360 361 if (m->m_len < off + sizeof(uint32_t)) { 362 m = m_pullup(m, off + sizeof(uint32_t)); 363 if (!m) { 364 /* if payload length < 4 octets */ 365 return 0; 366 } 367 } 368 369 /* get L2TP session ID */ 370 m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id); 371 NTOHL(sess_id); 372 if (sess_id == 0) { 373 /* 374 * L2TPv3 control packet received. 375 * userland daemon(l2tpd?) should process. 376 */ 377 return 128 * 2; 378 } else if (sess_id == var->lv_my_sess_id) 379 return 128 * 2; 380 else 381 return 0; 382 } 383 384 int 385 in6_l2tp_attach(struct l2tp_variant *var) 386 { 387 388 var->lv_encap_cookie = encap_attach_func(AF_INET6, IPPROTO_L2TP, 389 in6_l2tp_match, &in6_l2tp_encapsw, var); 390 if (var->lv_encap_cookie == NULL) 391 return EEXIST; 392 393 return 0; 394 } 395 396 int 397 in6_l2tp_detach(struct l2tp_variant *var) 398 { 399 int error; 400 401 error = encap_detach(var->lv_encap_cookie); 402 if (error == 0) 403 var->lv_encap_cookie = NULL; 404 405 return error; 406 } 407
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