1 /*- 2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the project nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $KAME: in6_rmx.c,v 1.11 2001/07/26 06:53:16 jinmei Exp $ 30 */ 31 32 /*- 33 * Copyright 1994, 1995 Massachusetts Institute of Technology 34 * 35 * Permission to use, copy, modify, and distribute this software and 36 * its documentation for any purpose and without fee is hereby 37 * granted, provided that both the above copyright notice and this 38 * permission notice appear in all copies, that both the above 39 * copyright notice and this permission notice appear in all 40 * supporting documentation, and that the name of M.I.T. not be used 41 * in advertising or publicity pertaining to distribution of the 42 * software without specific, written prior permission. M.I.T. makes 43 * no representations about the suitability of this software for any 44 * purpose. It is provided "as is" without express or implied 45 * warranty. 46 * 47 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS 48 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, 49 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 50 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 51 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 52 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 53 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 54 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 55 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 56 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 57 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 58 * SUCH DAMAGE. 59 * 60 */ 61 62 /* 63 * This code does two things necessary for the enhanced TCP metrics to 64 * function in a useful manner: 65 * 1) It marks all non-host routes as `cloning', thus ensuring that 66 * every actual reference to such a route actually gets turned 67 * into a reference to a host route to the specific destination 68 * requested. 69 * 2) When such routes lose all their references, it arranges for them 70 * to be deleted in some random collection of circumstances, so that 71 * a large quantity of stale routing data is not kept in kernel memory 72 * indefinitely. See in6_rtqtimo() below for the exact mechanism. 73 */ 74 75 #include <sys/cdefs.h> 76 __FBSDID("$FreeBSD$"); 77 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/kernel.h> 81 #include <sys/sysctl.h> 82 #include <sys/queue.h> 83 #include <sys/socket.h> 84 #include <sys/socketvar.h> 85 #include <sys/mbuf.h> 86 #include <sys/syslog.h> 87 #include <sys/callout.h> 88 89 #include <net/if.h> 90 #include <net/route.h> 91 #include <netinet/in.h> 92 #include <netinet/ip_var.h> 93 #include <netinet/in_var.h> 94 95 #include <netinet/ip6.h> 96 #include <netinet6/ip6_var.h> 97 98 #include <netinet/icmp6.h> 99 #include <netinet6/nd6.h> 100 101 #include <netinet/tcp.h> 102 #include <netinet/tcp_seq.h> 103 #include <netinet/tcp_timer.h> 104 #include <netinet/tcp_var.h> 105 106 extern int in6_inithead(void **head, int off); 107 108 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */ 109 110 /* 111 * Do what we need to do when inserting a route. 112 */ 113 static struct radix_node * 114 in6_addroute(void *v_arg, void *n_arg, struct radix_node_head *head, 115 struct radix_node *treenodes) 116 { 117 struct rtentry *rt = (struct rtentry *)treenodes; 118 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)rt_key(rt); 119 struct radix_node *ret; 120 121 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 122 rt->rt_flags |= RTF_MULTICAST; 123 124 /* 125 * A little bit of help for both IPv6 output and input: 126 * For local addresses, we make sure that RTF_LOCAL is set, 127 * with the thought that this might one day be used to speed up 128 * ip_input(). 129 * 130 * We also mark routes to multicast addresses as such, because 131 * it's easy to do and might be useful (but this is much more 132 * dubious since it's so easy to inspect the address). (This 133 * is done above.) 134 * 135 * XXX 136 * should elaborate the code. 137 */ 138 if (rt->rt_flags & RTF_HOST) { 139 if (IN6_ARE_ADDR_EQUAL(&satosin6(rt->rt_ifa->ifa_addr) 140 ->sin6_addr, 141 &sin6->sin6_addr)) { 142 rt->rt_flags |= RTF_LOCAL; 143 } 144 } 145 146 if (!rt->rt_rmx.rmx_mtu && rt->rt_ifp) 147 rt->rt_rmx.rmx_mtu = IN6_LINKMTU(rt->rt_ifp); 148 149 ret = rn_addroute(v_arg, n_arg, head, treenodes); 150 if (ret == NULL && rt->rt_flags & RTF_HOST) { 151 struct rtentry *rt2; 152 /* 153 * We are trying to add a host route, but can't. 154 * Find out if it is because of an 155 * ARP entry and delete it if so. 156 */ 157 rt2 = rtalloc1((struct sockaddr *)sin6, 0, RTF_CLONING); 158 if (rt2) { 159 if (rt2->rt_flags & RTF_LLINFO && 160 rt2->rt_flags & RTF_HOST && 161 rt2->rt_gateway && 162 rt2->rt_gateway->sa_family == AF_LINK) { 163 rtexpunge(rt2); 164 RTFREE_LOCKED(rt2); 165 ret = rn_addroute(v_arg, n_arg, head, 166 treenodes); 167 } else 168 RTFREE_LOCKED(rt2); 169 } 170 } else if (ret == NULL && rt->rt_flags & RTF_CLONING) { 171 struct rtentry *rt2; 172 /* 173 * We are trying to add a net route, but can't. 174 * The following case should be allowed, so we'll make a 175 * special check for this: 176 * Two IPv6 addresses with the same prefix is assigned 177 * to a single interrface. 178 * # ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1) 179 * # ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2) 180 * In this case, (*1) and (*2) want to add the same 181 * net route entry, 3ffe:0501:: -> if0. 182 * This case should not raise an error. 183 */ 184 rt2 = rtalloc1((struct sockaddr *)sin6, 0, RTF_CLONING); 185 if (rt2) { 186 if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY)) 187 == RTF_CLONING 188 && rt2->rt_gateway 189 && rt2->rt_gateway->sa_family == AF_LINK 190 && rt2->rt_ifp == rt->rt_ifp) { 191 ret = rt2->rt_nodes; 192 } 193 RTFREE_LOCKED(rt2); 194 } 195 } 196 return ret; 197 } 198 199 /* 200 * This code is the inverse of in6_clsroute: on first reference, if we 201 * were managing the route, stop doing so and set the expiration timer 202 * back off again. 203 */ 204 static struct radix_node * 205 in6_matroute(void *v_arg, struct radix_node_head *head) 206 { 207 struct radix_node *rn = rn_match(v_arg, head); 208 struct rtentry *rt = (struct rtentry *)rn; 209 210 if (rt && rt->rt_refcnt == 0) { /* this is first reference */ 211 if (rt->rt_flags & RTPRF_OURS) { 212 rt->rt_flags &= ~RTPRF_OURS; 213 rt->rt_rmx.rmx_expire = 0; 214 } 215 } 216 return rn; 217 } 218 219 SYSCTL_DECL(_net_inet6_ip6); 220 221 static int rtq_reallyold = 60*60; 222 /* one hour is ``really old'' */ 223 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTEXPIRE, rtexpire, 224 CTLFLAG_RW, &rtq_reallyold , 0, ""); 225 226 static int rtq_minreallyold = 10; 227 /* never automatically crank down to less */ 228 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMINEXPIRE, rtminexpire, 229 CTLFLAG_RW, &rtq_minreallyold , 0, ""); 230 231 static int rtq_toomany = 128; 232 /* 128 cached routes is ``too many'' */ 233 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMAXCACHE, rtmaxcache, 234 CTLFLAG_RW, &rtq_toomany , 0, ""); 235 236 237 /* 238 * On last reference drop, mark the route as belong to us so that it can be 239 * timed out. 240 */ 241 static void 242 in6_clsroute(struct radix_node *rn, struct radix_node_head *head) 243 { 244 struct rtentry *rt = (struct rtentry *)rn; 245 246 RT_LOCK_ASSERT(rt); 247 248 if (!(rt->rt_flags & RTF_UP)) 249 return; /* prophylactic measures */ 250 251 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST) 252 return; 253 254 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS)) != RTF_WASCLONED) 255 return; 256 257 /* 258 * As requested by David Greenman: 259 * If rtq_reallyold is 0, just delete the route without 260 * waiting for a timeout cycle to kill it. 261 */ 262 if (rtq_reallyold != 0) { 263 rt->rt_flags |= RTPRF_OURS; 264 rt->rt_rmx.rmx_expire = time_uptime + rtq_reallyold; 265 } else { 266 rtexpunge(rt); 267 } 268 } 269 270 struct rtqk_arg { 271 struct radix_node_head *rnh; 272 int mode; 273 int updating; 274 int draining; 275 int killed; 276 int found; 277 time_t nextstop; 278 }; 279 280 /* 281 * Get rid of old routes. When draining, this deletes everything, even when 282 * the timeout is not expired yet. When updating, this makes sure that 283 * nothing has a timeout longer than the current value of rtq_reallyold. 284 */ 285 static int 286 in6_rtqkill(struct radix_node *rn, void *rock) 287 { 288 struct rtqk_arg *ap = rock; 289 struct rtentry *rt = (struct rtentry *)rn; 290 int err; 291 292 if (rt->rt_flags & RTPRF_OURS) { 293 ap->found++; 294 295 if (ap->draining || rt->rt_rmx.rmx_expire <= time_uptime) { 296 if (rt->rt_refcnt > 0) 297 panic("rtqkill route really not free"); 298 299 err = rtrequest(RTM_DELETE, 300 (struct sockaddr *)rt_key(rt), 301 rt->rt_gateway, rt_mask(rt), 302 rt->rt_flags, 0); 303 if (err) { 304 log(LOG_WARNING, "in6_rtqkill: error %d", err); 305 } else { 306 ap->killed++; 307 } 308 } else { 309 if (ap->updating 310 && (rt->rt_rmx.rmx_expire - time_uptime 311 > rtq_reallyold)) { 312 rt->rt_rmx.rmx_expire = time_uptime 313 + rtq_reallyold; 314 } 315 ap->nextstop = lmin(ap->nextstop, 316 rt->rt_rmx.rmx_expire); 317 } 318 } 319 320 return 0; 321 } 322 323 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */ 324 static int rtq_timeout = RTQ_TIMEOUT; 325 static struct callout rtq_timer; 326 327 static void 328 in6_rtqtimo(void *rock) 329 { 330 struct radix_node_head *rnh = rock; 331 struct rtqk_arg arg; 332 struct timeval atv; 333 static time_t last_adjusted_timeout = 0; 334 335 arg.found = arg.killed = 0; 336 arg.rnh = rnh; 337 arg.nextstop = time_uptime + rtq_timeout; 338 arg.draining = arg.updating = 0; 339 RADIX_NODE_HEAD_LOCK(rnh); 340 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 341 RADIX_NODE_HEAD_UNLOCK(rnh); 342 343 /* 344 * Attempt to be somewhat dynamic about this: 345 * If there are ``too many'' routes sitting around taking up space, 346 * then crank down the timeout, and see if we can't make some more 347 * go away. However, we make sure that we will never adjust more 348 * than once in rtq_timeout seconds, to keep from cranking down too 349 * hard. 350 */ 351 if ((arg.found - arg.killed > rtq_toomany) 352 && (time_uptime - last_adjusted_timeout >= rtq_timeout) 353 && rtq_reallyold > rtq_minreallyold) { 354 rtq_reallyold = 2*rtq_reallyold / 3; 355 if (rtq_reallyold < rtq_minreallyold) { 356 rtq_reallyold = rtq_minreallyold; 357 } 358 359 last_adjusted_timeout = time_uptime; 360 #ifdef DIAGNOSTIC 361 log(LOG_DEBUG, "in6_rtqtimo: adjusted rtq_reallyold to %d", 362 rtq_reallyold); 363 #endif 364 arg.found = arg.killed = 0; 365 arg.updating = 1; 366 RADIX_NODE_HEAD_LOCK(rnh); 367 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 368 RADIX_NODE_HEAD_UNLOCK(rnh); 369 } 370 371 atv.tv_usec = 0; 372 atv.tv_sec = arg.nextstop - time_uptime; 373 callout_reset(&rtq_timer, tvtohz(&atv), in6_rtqtimo, rock); 374 } 375 376 /* 377 * Age old PMTUs. 378 */ 379 struct mtuex_arg { 380 struct radix_node_head *rnh; 381 time_t nextstop; 382 }; 383 static struct callout rtq_mtutimer; 384 385 static int 386 in6_mtuexpire(struct radix_node *rn, void *rock) 387 { 388 struct rtentry *rt = (struct rtentry *)rn; 389 struct mtuex_arg *ap = rock; 390 391 /* sanity */ 392 if (!rt) 393 panic("rt == NULL in in6_mtuexpire"); 394 395 if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) { 396 if (rt->rt_rmx.rmx_expire <= time_uptime) { 397 rt->rt_flags |= RTF_PROBEMTU; 398 } else { 399 ap->nextstop = lmin(ap->nextstop, 400 rt->rt_rmx.rmx_expire); 401 } 402 } 403 404 return 0; 405 } 406 407 #define MTUTIMO_DEFAULT (60*1) 408 409 static void 410 in6_mtutimo(void *rock) 411 { 412 struct radix_node_head *rnh = rock; 413 struct mtuex_arg arg; 414 struct timeval atv; 415 416 arg.rnh = rnh; 417 arg.nextstop = time_uptime + MTUTIMO_DEFAULT; 418 RADIX_NODE_HEAD_LOCK(rnh); 419 rnh->rnh_walktree(rnh, in6_mtuexpire, &arg); 420 RADIX_NODE_HEAD_UNLOCK(rnh); 421 422 atv.tv_usec = 0; 423 atv.tv_sec = arg.nextstop - time_uptime; 424 if (atv.tv_sec < 0) { 425 printf("invalid mtu expiration time on routing table\n"); 426 arg.nextstop = time_uptime + 30; /* last resort */ 427 atv.tv_sec = 30; 428 } 429 callout_reset(&rtq_mtutimer, tvtohz(&atv), in6_mtutimo, rock); 430 } 431 432 #if 0 433 void 434 in6_rtqdrain(void) 435 { 436 struct radix_node_head *rnh = rt_tables[AF_INET6]; 437 struct rtqk_arg arg; 438 439 arg.found = arg.killed = 0; 440 arg.rnh = rnh; 441 arg.nextstop = 0; 442 arg.draining = 1; 443 arg.updating = 0; 444 RADIX_NODE_HEAD_LOCK(rnh); 445 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 446 RADIX_NODE_HEAD_UNLOCK(rnh); 447 } 448 #endif 449 450 /* 451 * Initialize our routing tree. 452 */ 453 int 454 in6_inithead(void **head, int off) 455 { 456 struct radix_node_head *rnh; 457 458 if (!rn_inithead(head, off)) 459 return 0; 460 461 if (head != (void **)&rt_tables[AF_INET6]) /* BOGUS! */ 462 return 1; /* only do this for the real routing table */ 463 464 rnh = *head; 465 rnh->rnh_addaddr = in6_addroute; 466 rnh->rnh_matchaddr = in6_matroute; 467 rnh->rnh_close = in6_clsroute; 468 callout_init(&rtq_timer, CALLOUT_MPSAFE); 469 in6_rtqtimo(rnh); /* kick off timeout first time */ 470 callout_init(&rtq_mtutimer, CALLOUT_MPSAFE); 471 in6_mtutimo(rnh); /* kick off timeout first time */ 472 return 1; 473 } 474