1 /* $FreeBSD: src/sys/netinet6/in6_rmx.c,v 1.1.2.3 2002/04/28 05:40:27 suz Exp $ */ 2 /* $DragonFly: src/sys/netinet6/in6_rmx.c,v 1.4 2004/01/07 11:07:04 dillon Exp $ */ 3 /* $KAME: in6_rmx.c,v 1.11 2001/07/26 06:53:16 jinmei Exp $ */ 4 5 /* 6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the project nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright 1994, 1995 Massachusetts Institute of Technology 36 * 37 * Permission to use, copy, modify, and distribute this software and 38 * its documentation for any purpose and without fee is hereby 39 * granted, provided that both the above copyright notice and this 40 * permission notice appear in all copies, that both the above 41 * copyright notice and this permission notice appear in all 42 * supporting documentation, and that the name of M.I.T. not be used 43 * in advertising or publicity pertaining to distribution of the 44 * software without specific, written prior permission. M.I.T. makes 45 * no representations about the suitability of this software for any 46 * purpose. It is provided "as is" without express or implied 47 * warranty. 48 * 49 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS 50 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, 51 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 52 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 53 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 54 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 55 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 56 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 57 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 58 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 59 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 * 62 */ 63 64 /* 65 * This code does two things necessary for the enhanced TCP metrics to 66 * function in a useful manner: 67 * 1) It marks all non-host routes as `cloning', thus ensuring that 68 * every actual reference to such a route actually gets turned 69 * into a reference to a host route to the specific destination 70 * requested. 71 * 2) When such routes lose all their references, it arranges for them 72 * to be deleted in some random collection of circumstances, so that 73 * a large quantity of stale routing data is not kept in kernel memory 74 * indefinitely. See in6_rtqtimo() below for the exact mechanism. 75 */ 76 77 #include <sys/param.h> 78 #include <sys/systm.h> 79 #include <sys/kernel.h> 80 #include <sys/sysctl.h> 81 #include <sys/queue.h> 82 #include <sys/socket.h> 83 #include <sys/socketvar.h> 84 #include <sys/mbuf.h> 85 #include <sys/syslog.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 98 #include <netinet/tcp.h> 99 #include <netinet/tcp_seq.h> 100 #include <netinet/tcp_timer.h> 101 #include <netinet/tcp_var.h> 102 103 extern int in6_inithead (void **head, int off); 104 105 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */ 106 107 /* 108 * Do what we need to do when inserting a route. 109 */ 110 static struct radix_node * 111 in6_addroute(void *v_arg, void *n_arg, struct radix_node_head *head, 112 struct radix_node *treenodes) 113 { 114 struct rtentry *rt = (struct rtentry *)treenodes; 115 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)rt_key(rt); 116 struct radix_node *ret; 117 118 /* 119 * For IPv6, all unicast non-host routes are automatically cloning. 120 */ 121 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 122 rt->rt_flags |= RTF_MULTICAST; 123 124 if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) { 125 rt->rt_flags |= RTF_PRCLONING; 126 } 127 128 /* 129 * A little bit of help for both IPv6 output and input: 130 * For local addresses, we make sure that RTF_LOCAL is set, 131 * with the thought that this might one day be used to speed up 132 * ip_input(). 133 * 134 * We also mark routes to multicast addresses as such, because 135 * it's easy to do and might be useful (but this is much more 136 * dubious since it's so easy to inspect the address). (This 137 * is done above.) 138 * 139 * XXX 140 * should elaborate the code. 141 */ 142 if (rt->rt_flags & RTF_HOST) { 143 if (IN6_ARE_ADDR_EQUAL(&satosin6(rt->rt_ifa->ifa_addr) 144 ->sin6_addr, 145 &sin6->sin6_addr)) { 146 rt->rt_flags |= RTF_LOCAL; 147 } 148 } 149 150 if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU) 151 && rt->rt_ifp) 152 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; 153 154 ret = rn_addroute(v_arg, n_arg, head, treenodes); 155 if (ret == NULL && rt->rt_flags & RTF_HOST) { 156 struct rtentry *rt2; 157 /* 158 * We are trying to add a host route, but can't. 159 * Find out if it is because of an 160 * ARP entry and delete it if so. 161 */ 162 rt2 = rtalloc1((struct sockaddr *)sin6, 0, 163 RTF_CLONING | RTF_PRCLONING); 164 if (rt2) { 165 if (rt2->rt_flags & RTF_LLINFO && 166 rt2->rt_flags & RTF_HOST && 167 rt2->rt_gateway && 168 rt2->rt_gateway->sa_family == AF_LINK) { 169 rtrequest(RTM_DELETE, 170 (struct sockaddr *)rt_key(rt2), 171 rt2->rt_gateway, 172 rt_mask(rt2), rt2->rt_flags, 0); 173 ret = rn_addroute(v_arg, n_arg, head, 174 treenodes); 175 } 176 RTFREE(rt2); 177 } 178 } else if (ret == NULL && rt->rt_flags & RTF_CLONING) { 179 struct rtentry *rt2; 180 /* 181 * We are trying to add a net route, but can't. 182 * The following case should be allowed, so we'll make a 183 * special check for this: 184 * Two IPv6 addresses with the same prefix is assigned 185 * to a single interrface. 186 * # ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1) 187 * # ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2) 188 * In this case, (*1) and (*2) want to add the same 189 * net route entry, 3ffe:0501:: -> if0. 190 * This case should not raise an error. 191 */ 192 rt2 = rtalloc1((struct sockaddr *)sin6, 0, 193 RTF_CLONING | RTF_PRCLONING); 194 if (rt2) { 195 if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY)) 196 == RTF_CLONING 197 && rt2->rt_gateway 198 && rt2->rt_gateway->sa_family == AF_LINK 199 && rt2->rt_ifp == rt->rt_ifp) { 200 ret = rt2->rt_nodes; 201 } 202 RTFREE(rt2); 203 } 204 } 205 return ret; 206 } 207 208 /* 209 * This code is the inverse of in6_clsroute: on first reference, if we 210 * were managing the route, stop doing so and set the expiration timer 211 * back off again. 212 */ 213 static struct radix_node * 214 in6_matroute(void *v_arg, struct radix_node_head *head) 215 { 216 struct radix_node *rn = rn_match(v_arg, head); 217 struct rtentry *rt = (struct rtentry *)rn; 218 219 if (rt && rt->rt_refcnt == 0) { /* this is first reference */ 220 if (rt->rt_flags & RTPRF_OURS) { 221 rt->rt_flags &= ~RTPRF_OURS; 222 rt->rt_rmx.rmx_expire = 0; 223 } 224 } 225 return rn; 226 } 227 228 SYSCTL_DECL(_net_inet6_ip6); 229 230 static int rtq_reallyold = 60*60; 231 /* one hour is ``really old'' */ 232 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTEXPIRE, rtexpire, 233 CTLFLAG_RW, &rtq_reallyold , 0, ""); 234 235 static int rtq_minreallyold = 10; 236 /* never automatically crank down to less */ 237 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMINEXPIRE, rtminexpire, 238 CTLFLAG_RW, &rtq_minreallyold , 0, ""); 239 240 static int rtq_toomany = 128; 241 /* 128 cached routes is ``too many'' */ 242 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMAXCACHE, rtmaxcache, 243 CTLFLAG_RW, &rtq_toomany , 0, ""); 244 245 246 /* 247 * On last reference drop, mark the route as belong to us so that it can be 248 * timed out. 249 */ 250 static void 251 in6_clsroute(struct radix_node *rn, struct radix_node_head *head) 252 { 253 struct rtentry *rt = (struct rtentry *)rn; 254 255 if (!(rt->rt_flags & RTF_UP)) 256 return; /* prophylactic measures */ 257 258 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST) 259 return; 260 261 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS)) 262 != RTF_WASCLONED) 263 return; 264 265 /* 266 * As requested by David Greenman: 267 * If rtq_reallyold is 0, just delete the route without 268 * waiting for a timeout cycle to kill it. 269 */ 270 if (rtq_reallyold != 0) { 271 rt->rt_flags |= RTPRF_OURS; 272 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold; 273 } else { 274 rtrequest(RTM_DELETE, 275 (struct sockaddr *)rt_key(rt), 276 rt->rt_gateway, rt_mask(rt), 277 rt->rt_flags, 0); 278 } 279 } 280 281 struct rtqk_arg { 282 struct radix_node_head *rnh; 283 int mode; 284 int updating; 285 int draining; 286 int killed; 287 int found; 288 time_t nextstop; 289 }; 290 291 /* 292 * Get rid of old routes. When draining, this deletes everything, even when 293 * the timeout is not expired yet. When updating, this makes sure that 294 * nothing has a timeout longer than the current value of rtq_reallyold. 295 */ 296 static int 297 in6_rtqkill(struct radix_node *rn, void *rock) 298 { 299 struct rtqk_arg *ap = rock; 300 struct rtentry *rt = (struct rtentry *)rn; 301 int err; 302 303 if (rt->rt_flags & RTPRF_OURS) { 304 ap->found++; 305 306 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) { 307 if (rt->rt_refcnt > 0) 308 panic("rtqkill route really not free"); 309 310 err = rtrequest(RTM_DELETE, 311 (struct sockaddr *)rt_key(rt), 312 rt->rt_gateway, rt_mask(rt), 313 rt->rt_flags, 0); 314 if (err) { 315 log(LOG_WARNING, "in6_rtqkill: error %d", err); 316 } else { 317 ap->killed++; 318 } 319 } else { 320 if (ap->updating 321 && (rt->rt_rmx.rmx_expire - time_second 322 > rtq_reallyold)) { 323 rt->rt_rmx.rmx_expire = time_second 324 + rtq_reallyold; 325 } 326 ap->nextstop = lmin(ap->nextstop, 327 rt->rt_rmx.rmx_expire); 328 } 329 } 330 331 return 0; 332 } 333 334 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */ 335 static int rtq_timeout = RTQ_TIMEOUT; 336 337 static void 338 in6_rtqtimo(void *rock) 339 { 340 struct radix_node_head *rnh = rock; 341 struct rtqk_arg arg; 342 struct timeval atv; 343 static time_t last_adjusted_timeout = 0; 344 int s; 345 346 arg.found = arg.killed = 0; 347 arg.rnh = rnh; 348 arg.nextstop = time_second + rtq_timeout; 349 arg.draining = arg.updating = 0; 350 s = splnet(); 351 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 352 splx(s); 353 354 /* 355 * Attempt to be somewhat dynamic about this: 356 * If there are ``too many'' routes sitting around taking up space, 357 * then crank down the timeout, and see if we can't make some more 358 * go away. However, we make sure that we will never adjust more 359 * than once in rtq_timeout seconds, to keep from cranking down too 360 * hard. 361 */ 362 if ((arg.found - arg.killed > rtq_toomany) 363 && (time_second - last_adjusted_timeout >= rtq_timeout) 364 && rtq_reallyold > rtq_minreallyold) { 365 rtq_reallyold = 2*rtq_reallyold / 3; 366 if (rtq_reallyold < rtq_minreallyold) { 367 rtq_reallyold = rtq_minreallyold; 368 } 369 370 last_adjusted_timeout = time_second; 371 #ifdef DIAGNOSTIC 372 log(LOG_DEBUG, "in6_rtqtimo: adjusted rtq_reallyold to %d", 373 rtq_reallyold); 374 #endif 375 arg.found = arg.killed = 0; 376 arg.updating = 1; 377 s = splnet(); 378 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 379 splx(s); 380 } 381 382 atv.tv_usec = 0; 383 atv.tv_sec = arg.nextstop; 384 timeout(in6_rtqtimo, rock, tvtohz_high(&atv)); 385 } 386 387 /* 388 * Age old PMTUs. 389 */ 390 struct mtuex_arg { 391 struct radix_node_head *rnh; 392 time_t nextstop; 393 }; 394 395 static int 396 in6_mtuexpire(struct radix_node *rn, void *rock) 397 { 398 struct rtentry *rt = (struct rtentry *)rn; 399 struct mtuex_arg *ap = rock; 400 401 /* sanity */ 402 if (!rt) 403 panic("rt == NULL in in6_mtuexpire"); 404 405 if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) { 406 if (rt->rt_rmx.rmx_expire <= time_second) { 407 rt->rt_flags |= RTF_PROBEMTU; 408 } else { 409 ap->nextstop = lmin(ap->nextstop, 410 rt->rt_rmx.rmx_expire); 411 } 412 } 413 414 return 0; 415 } 416 417 #define MTUTIMO_DEFAULT (60*1) 418 419 static void 420 in6_mtutimo(void *rock) 421 { 422 struct radix_node_head *rnh = rock; 423 struct mtuex_arg arg; 424 struct timeval atv; 425 int s; 426 427 arg.rnh = rnh; 428 arg.nextstop = time_second + MTUTIMO_DEFAULT; 429 s = splnet(); 430 rnh->rnh_walktree(rnh, in6_mtuexpire, &arg); 431 splx(s); 432 433 atv.tv_usec = 0; 434 atv.tv_sec = arg.nextstop; 435 if (atv.tv_sec < time_second) { 436 printf("invalid mtu expiration time on routing table\n"); 437 arg.nextstop = time_second + 30; /* last resort */ 438 } 439 timeout(in6_mtutimo, rock, tvtohz_high(&atv)); 440 } 441 442 #if 0 443 void 444 in6_rtqdrain() 445 { 446 struct radix_node_head *rnh = rt_tables[AF_INET6]; 447 struct rtqk_arg arg; 448 int s; 449 arg.found = arg.killed = 0; 450 arg.rnh = rnh; 451 arg.nextstop = 0; 452 arg.draining = 1; 453 arg.updating = 0; 454 s = splnet(); 455 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 456 splx(s); 457 } 458 #endif 459 460 /* 461 * Initialize our routing tree. 462 */ 463 int 464 in6_inithead(void **head, int off) 465 { 466 struct radix_node_head *rnh; 467 468 if (!rn_inithead(head, off)) 469 return 0; 470 471 if (head != (void **)&rt_tables[AF_INET6]) /* BOGUS! */ 472 return 1; /* only do this for the real routing table */ 473 474 rnh = *head; 475 rnh->rnh_addaddr = in6_addroute; 476 rnh->rnh_matchaddr = in6_matroute; 477 rnh->rnh_close = in6_clsroute; 478 in6_rtqtimo(rnh); /* kick off timeout first time */ 479 in6_mtutimo(rnh); /* kick off timeout first time */ 480 return 1; 481 } 482