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