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 86 #include <net/if.h> 87 #include <net/route.h> 88 #include <netinet/in.h> 89 #include <netinet/ip_var.h> 90 #include <netinet/in_var.h> 91 92 #include <netinet/ip6.h> 93 #include <netinet6/ip6_var.h> 94 95 #include <netinet/icmp6.h> 96 97 #include <netinet/tcp.h> 98 #include <netinet/tcp_seq.h> 99 #include <netinet/tcp_timer.h> 100 #include <netinet/tcp_var.h> 101 102 extern int in6_inithead __P((void **head, int off)); 103 104 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */ 105 106 /* 107 * Do what we need to do when inserting a route. 108 */ 109 static struct radix_node * 110 in6_addroute(void *v_arg, void *n_arg, struct radix_node_head *head, 111 struct radix_node *treenodes) 112 { 113 struct rtentry *rt = (struct rtentry *)treenodes; 114 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)rt_key(rt); 115 struct radix_node *ret; 116 117 /* 118 * For IPv6, all unicast non-host routes are automatically cloning. 119 */ 120 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 121 rt->rt_flags |= RTF_MULTICAST; 122 123 if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) { 124 rt->rt_flags |= RTF_PRCLONING; 125 } 126 127 /* 128 * A little bit of help for both IPv6 output and input: 129 * For local addresses, we make sure that RTF_LOCAL is set, 130 * with the thought that this might one day be used to speed up 131 * ip_input(). 132 * 133 * We also mark routes to multicast addresses as such, because 134 * it's easy to do and might be useful (but this is much more 135 * dubious since it's so easy to inspect the address). (This 136 * is done above.) 137 * 138 * XXX 139 * should elaborate the code. 140 */ 141 if (rt->rt_flags & RTF_HOST) { 142 if (IN6_ARE_ADDR_EQUAL(&satosin6(rt->rt_ifa->ifa_addr) 143 ->sin6_addr, 144 &sin6->sin6_addr)) { 145 rt->rt_flags |= RTF_LOCAL; 146 } 147 } 148 149 if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU) 150 && rt->rt_ifp) 151 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; 152 153 ret = rn_addroute(v_arg, n_arg, head, treenodes); 154 if (ret == NULL && rt->rt_flags & RTF_HOST) { 155 struct rtentry *rt2; 156 /* 157 * We are trying to add a host route, but can't. 158 * Find out if it is because of an 159 * ARP entry and delete it if so. 160 */ 161 rt2 = rtalloc1((struct sockaddr *)sin6, 0, 162 RTF_CLONING | RTF_PRCLONING); 163 if (rt2) { 164 if (rt2->rt_flags & RTF_LLINFO && 165 rt2->rt_flags & RTF_HOST && 166 rt2->rt_gateway && 167 rt2->rt_gateway->sa_family == AF_LINK) { 168 rtrequest(RTM_DELETE, 169 (struct sockaddr *)rt_key(rt2), 170 rt2->rt_gateway, 171 rt_mask(rt2), rt2->rt_flags, 0); 172 ret = rn_addroute(v_arg, n_arg, head, 173 treenodes); 174 } 175 RTFREE(rt2); 176 } 177 } else if (ret == NULL && rt->rt_flags & RTF_CLONING) { 178 struct rtentry *rt2; 179 /* 180 * We are trying to add a net route, but can't. 181 * The following case should be allowed, so we'll make a 182 * special check for this: 183 * Two IPv6 addresses with the same prefix is assigned 184 * to a single interrface. 185 * # ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1) 186 * # ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2) 187 * In this case, (*1) and (*2) want to add the same 188 * net route entry, 3ffe:0501:: -> if0. 189 * This case should not raise an error. 190 */ 191 rt2 = rtalloc1((struct sockaddr *)sin6, 0, 192 RTF_CLONING | RTF_PRCLONING); 193 if (rt2) { 194 if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY)) 195 == RTF_CLONING 196 && rt2->rt_gateway 197 && rt2->rt_gateway->sa_family == AF_LINK 198 && rt2->rt_ifp == rt->rt_ifp) { 199 ret = rt2->rt_nodes; 200 } 201 RTFREE(rt2); 202 } 203 } 204 return ret; 205 } 206 207 /* 208 * This code is the inverse of in6_clsroute: on first reference, if we 209 * were managing the route, stop doing so and set the expiration timer 210 * back off again. 211 */ 212 static struct radix_node * 213 in6_matroute(void *v_arg, struct radix_node_head *head) 214 { 215 struct radix_node *rn = rn_match(v_arg, head); 216 struct rtentry *rt = (struct rtentry *)rn; 217 218 if (rt && rt->rt_refcnt == 0) { /* this is first reference */ 219 if (rt->rt_flags & RTPRF_OURS) { 220 rt->rt_flags &= ~RTPRF_OURS; 221 rt->rt_rmx.rmx_expire = 0; 222 } 223 } 224 return rn; 225 } 226 227 SYSCTL_DECL(_net_inet6_ip6); 228 229 static int rtq_reallyold = 60*60; 230 /* one hour is ``really old'' */ 231 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTEXPIRE, rtexpire, 232 CTLFLAG_RW, &rtq_reallyold , 0, ""); 233 234 static int rtq_minreallyold = 10; 235 /* never automatically crank down to less */ 236 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMINEXPIRE, rtminexpire, 237 CTLFLAG_RW, &rtq_minreallyold , 0, ""); 238 239 static int rtq_toomany = 128; 240 /* 128 cached routes is ``too many'' */ 241 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMAXCACHE, rtmaxcache, 242 CTLFLAG_RW, &rtq_toomany , 0, ""); 243 244 245 /* 246 * On last reference drop, mark the route as belong to us so that it can be 247 * timed out. 248 */ 249 static void 250 in6_clsroute(struct radix_node *rn, struct radix_node_head *head) 251 { 252 struct rtentry *rt = (struct rtentry *)rn; 253 254 if (!(rt->rt_flags & RTF_UP)) 255 return; /* prophylactic measures */ 256 257 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST) 258 return; 259 260 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS)) 261 != RTF_WASCLONED) 262 return; 263 264 /* 265 * As requested by David Greenman: 266 * If rtq_reallyold is 0, just delete the route without 267 * waiting for a timeout cycle to kill it. 268 */ 269 if (rtq_reallyold != 0) { 270 rt->rt_flags |= RTPRF_OURS; 271 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold; 272 } else { 273 rtrequest(RTM_DELETE, 274 (struct sockaddr *)rt_key(rt), 275 rt->rt_gateway, rt_mask(rt), 276 rt->rt_flags, 0); 277 } 278 } 279 280 struct rtqk_arg { 281 struct radix_node_head *rnh; 282 int mode; 283 int updating; 284 int draining; 285 int killed; 286 int found; 287 time_t nextstop; 288 }; 289 290 /* 291 * Get rid of old routes. When draining, this deletes everything, even when 292 * the timeout is not expired yet. When updating, this makes sure that 293 * nothing has a timeout longer than the current value of rtq_reallyold. 294 */ 295 static int 296 in6_rtqkill(struct radix_node *rn, void *rock) 297 { 298 struct rtqk_arg *ap = rock; 299 struct rtentry *rt = (struct rtentry *)rn; 300 int err; 301 302 if (rt->rt_flags & RTPRF_OURS) { 303 ap->found++; 304 305 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) { 306 if (rt->rt_refcnt > 0) 307 panic("rtqkill route really not free"); 308 309 err = rtrequest(RTM_DELETE, 310 (struct sockaddr *)rt_key(rt), 311 rt->rt_gateway, rt_mask(rt), 312 rt->rt_flags, 0); 313 if (err) { 314 log(LOG_WARNING, "in6_rtqkill: error %d", err); 315 } else { 316 ap->killed++; 317 } 318 } else { 319 if (ap->updating 320 && (rt->rt_rmx.rmx_expire - time_second 321 > rtq_reallyold)) { 322 rt->rt_rmx.rmx_expire = time_second 323 + rtq_reallyold; 324 } 325 ap->nextstop = lmin(ap->nextstop, 326 rt->rt_rmx.rmx_expire); 327 } 328 } 329 330 return 0; 331 } 332 333 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */ 334 static int rtq_timeout = RTQ_TIMEOUT; 335 336 static void 337 in6_rtqtimo(void *rock) 338 { 339 struct radix_node_head *rnh = rock; 340 struct rtqk_arg arg; 341 struct timeval atv; 342 static time_t last_adjusted_timeout = 0; 343 int s; 344 345 arg.found = arg.killed = 0; 346 arg.rnh = rnh; 347 arg.nextstop = time_second + rtq_timeout; 348 arg.draining = arg.updating = 0; 349 s = splnet(); 350 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 351 splx(s); 352 353 /* 354 * Attempt to be somewhat dynamic about this: 355 * If there are ``too many'' routes sitting around taking up space, 356 * then crank down the timeout, and see if we can't make some more 357 * go away. However, we make sure that we will never adjust more 358 * than once in rtq_timeout seconds, to keep from cranking down too 359 * hard. 360 */ 361 if ((arg.found - arg.killed > rtq_toomany) 362 && (time_second - last_adjusted_timeout >= rtq_timeout) 363 && rtq_reallyold > rtq_minreallyold) { 364 rtq_reallyold = 2*rtq_reallyold / 3; 365 if (rtq_reallyold < rtq_minreallyold) { 366 rtq_reallyold = rtq_minreallyold; 367 } 368 369 last_adjusted_timeout = time_second; 370 #ifdef DIAGNOSTIC 371 log(LOG_DEBUG, "in6_rtqtimo: adjusted rtq_reallyold to %d", 372 rtq_reallyold); 373 #endif 374 arg.found = arg.killed = 0; 375 arg.updating = 1; 376 s = splnet(); 377 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 378 splx(s); 379 } 380 381 atv.tv_usec = 0; 382 atv.tv_sec = arg.nextstop; 383 timeout(in6_rtqtimo, rock, tvtohz(&atv)); 384 } 385 386 /* 387 * Age old PMTUs. 388 */ 389 struct mtuex_arg { 390 struct radix_node_head *rnh; 391 time_t nextstop; 392 }; 393 394 static int 395 in6_mtuexpire(struct radix_node *rn, void *rock) 396 { 397 struct rtentry *rt = (struct rtentry *)rn; 398 struct mtuex_arg *ap = rock; 399 400 /* sanity */ 401 if (!rt) 402 panic("rt == NULL in in6_mtuexpire"); 403 404 if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) { 405 if (rt->rt_rmx.rmx_expire <= time_second) { 406 rt->rt_flags |= RTF_PROBEMTU; 407 } else { 408 ap->nextstop = lmin(ap->nextstop, 409 rt->rt_rmx.rmx_expire); 410 } 411 } 412 413 return 0; 414 } 415 416 #define MTUTIMO_DEFAULT (60*1) 417 418 static void 419 in6_mtutimo(void *rock) 420 { 421 struct radix_node_head *rnh = rock; 422 struct mtuex_arg arg; 423 struct timeval atv; 424 int s; 425 426 arg.rnh = rnh; 427 arg.nextstop = time_second + MTUTIMO_DEFAULT; 428 s = splnet(); 429 rnh->rnh_walktree(rnh, in6_mtuexpire, &arg); 430 splx(s); 431 432 atv.tv_usec = 0; 433 atv.tv_sec = arg.nextstop; 434 if (atv.tv_sec < time_second) { 435 printf("invalid mtu expiration time on routing table\n"); 436 arg.nextstop = time_second + 30; /* last resort */ 437 } 438 timeout(in6_mtutimo, rock, tvtohz(&atv)); 439 } 440 441 #if 0 442 void 443 in6_rtqdrain() 444 { 445 struct radix_node_head *rnh = rt_tables[AF_INET6]; 446 struct rtqk_arg arg; 447 int s; 448 arg.found = arg.killed = 0; 449 arg.rnh = rnh; 450 arg.nextstop = 0; 451 arg.draining = 1; 452 arg.updating = 0; 453 s = splnet(); 454 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 455 splx(s); 456 } 457 #endif 458 459 /* 460 * Initialize our routing tree. 461 */ 462 int 463 in6_inithead(void **head, int off) 464 { 465 struct radix_node_head *rnh; 466 467 if (!rn_inithead(head, off)) 468 return 0; 469 470 if (head != (void **)&rt_tables[AF_INET6]) /* BOGUS! */ 471 return 1; /* only do this for the real routing table */ 472 473 rnh = *head; 474 rnh->rnh_addaddr = in6_addroute; 475 rnh->rnh_matchaddr = in6_matroute; 476 rnh->rnh_close = in6_clsroute; 477 in6_rtqtimo(rnh); /* kick off timeout first time */ 478 in6_mtutimo(rnh); /* kick off timeout first time */ 479 return 1; 480 } 481