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 * $FreeBSD$ 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 * $Id: in6_rmx.c,v 1.3 1999/08/16 13:42:53 itojun Exp $ 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 <netinet6/ip6.h> 93 #include <netinet6/ip6_var.h> 94 95 #include <netinet6/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 /* 150 * We also specify a send and receive pipe size for every 151 * route added, to help TCP a bit. TCP doesn't actually 152 * want a true pipe size, which would be prohibitive in memory 153 * costs and is hard to compute anyway; it simply uses these 154 * values to size its buffers. So, we fill them in with the 155 * same values that TCP would have used anyway, and allow the 156 * installing program or the link layer to override these values 157 * as it sees fit. This will hopefully allow TCP more 158 * opportunities to save its ssthresh value. 159 */ 160 if (!rt->rt_rmx.rmx_sendpipe && !(rt->rt_rmx.rmx_locks & RTV_SPIPE)) 161 rt->rt_rmx.rmx_sendpipe = tcp_sendspace; 162 163 if (!rt->rt_rmx.rmx_recvpipe && !(rt->rt_rmx.rmx_locks & RTV_RPIPE)) 164 rt->rt_rmx.rmx_recvpipe = tcp_recvspace; 165 166 if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU) 167 && rt->rt_ifp) 168 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; 169 170 ret = rn_addroute(v_arg, n_arg, head, treenodes); 171 if (ret == NULL && rt->rt_flags & RTF_HOST) { 172 struct rtentry *rt2; 173 /* 174 * We are trying to add a host route, but can't. 175 * Find out if it is because of an 176 * ARP entry and delete it if so. 177 */ 178 rt2 = rtalloc1((struct sockaddr *)sin6, 0, 179 RTF_CLONING | RTF_PRCLONING); 180 if (rt2) { 181 if (rt2->rt_flags & RTF_LLINFO && 182 rt2->rt_flags & RTF_HOST && 183 rt2->rt_gateway && 184 rt2->rt_gateway->sa_family == AF_LINK) { 185 rtrequest(RTM_DELETE, 186 (struct sockaddr *)rt_key(rt2), 187 rt2->rt_gateway, 188 rt_mask(rt2), rt2->rt_flags, 0); 189 ret = rn_addroute(v_arg, n_arg, head, 190 treenodes); 191 } 192 RTFREE(rt2); 193 } 194 } else if (ret == NULL && rt->rt_flags & RTF_CLONING) { 195 struct rtentry *rt2; 196 /* 197 * We are trying to add a net route, but can't. 198 * The following case should be allowed, so we'll make a 199 * special check for this: 200 * Two IPv6 addresses with the same prefix is assigned 201 * to a single interrface. 202 * # ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1) 203 * # ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2) 204 * In this case, (*1) and (*2) want to add the same 205 * net route entry, 3ffe:0501:: -> if0. 206 * This case should not raise an error. 207 */ 208 rt2 = rtalloc1((struct sockaddr *)sin6, 0, 209 RTF_CLONING | RTF_PRCLONING); 210 if (rt2) { 211 if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY)) 212 == RTF_CLONING 213 && rt2->rt_gateway 214 && rt2->rt_gateway->sa_family == AF_LINK 215 && rt2->rt_ifp == rt->rt_ifp) { 216 ret = rt2->rt_nodes; 217 } 218 RTFREE(rt2); 219 } 220 } 221 return ret; 222 } 223 224 /* 225 * This code is the inverse of in6_clsroute: on first reference, if we 226 * were managing the route, stop doing so and set the expiration timer 227 * back off again. 228 */ 229 static struct radix_node * 230 in6_matroute(void *v_arg, struct radix_node_head *head) 231 { 232 struct radix_node *rn = rn_match(v_arg, head); 233 struct rtentry *rt = (struct rtentry *)rn; 234 235 if (rt && rt->rt_refcnt == 0) { /* this is first reference */ 236 if (rt->rt_flags & RTPRF_OURS) { 237 rt->rt_flags &= ~RTPRF_OURS; 238 rt->rt_rmx.rmx_expire = 0; 239 } 240 } 241 return rn; 242 } 243 244 static int rtq_reallyold = 60*60; 245 /* one hour is ``really old'' */ 246 SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, 247 CTLFLAG_RW, &rtq_reallyold , 0, ""); 248 249 static int rtq_minreallyold = 10; 250 /* never automatically crank down to less */ 251 SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, 252 CTLFLAG_RW, &rtq_minreallyold , 0, ""); 253 254 static int rtq_toomany = 128; 255 /* 128 cached routes is ``too many'' */ 256 SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, 257 CTLFLAG_RW, &rtq_toomany , 0, ""); 258 259 260 /* 261 * On last reference drop, mark the route as belong to us so that it can be 262 * timed out. 263 */ 264 static void 265 in6_clsroute(struct radix_node *rn, struct radix_node_head *head) 266 { 267 struct rtentry *rt = (struct rtentry *)rn; 268 269 if (!(rt->rt_flags & RTF_UP)) 270 return; /* prophylactic measures */ 271 272 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST) 273 return; 274 275 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS)) 276 != RTF_WASCLONED) 277 return; 278 279 /* 280 * As requested by David Greenman: 281 * If rtq_reallyold is 0, just delete the route without 282 * waiting for a timeout cycle to kill it. 283 */ 284 if (rtq_reallyold != 0) { 285 rt->rt_flags |= RTPRF_OURS; 286 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold; 287 } else { 288 rtrequest(RTM_DELETE, 289 (struct sockaddr *)rt_key(rt), 290 rt->rt_gateway, rt_mask(rt), 291 rt->rt_flags, 0); 292 } 293 } 294 295 struct rtqk_arg { 296 struct radix_node_head *rnh; 297 int mode; 298 int updating; 299 int draining; 300 int killed; 301 int found; 302 time_t nextstop; 303 }; 304 305 /* 306 * Get rid of old routes. When draining, this deletes everything, even when 307 * the timeout is not expired yet. When updating, this makes sure that 308 * nothing has a timeout longer than the current value of rtq_reallyold. 309 */ 310 static int 311 in6_rtqkill(struct radix_node *rn, void *rock) 312 { 313 struct rtqk_arg *ap = rock; 314 struct rtentry *rt = (struct rtentry *)rn; 315 int err; 316 317 if (rt->rt_flags & RTPRF_OURS) { 318 ap->found++; 319 320 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) { 321 if (rt->rt_refcnt > 0) 322 panic("rtqkill route really not free"); 323 324 err = rtrequest(RTM_DELETE, 325 (struct sockaddr *)rt_key(rt), 326 rt->rt_gateway, rt_mask(rt), 327 rt->rt_flags, 0); 328 if (err) { 329 log(LOG_WARNING, "in6_rtqkill: error %d", err); 330 } else { 331 ap->killed++; 332 } 333 } else { 334 if (ap->updating 335 && (rt->rt_rmx.rmx_expire - time_second 336 > rtq_reallyold)) { 337 rt->rt_rmx.rmx_expire = time_second 338 + rtq_reallyold; 339 } 340 ap->nextstop = lmin(ap->nextstop, 341 rt->rt_rmx.rmx_expire); 342 } 343 } 344 345 return 0; 346 } 347 348 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */ 349 static int rtq_timeout = RTQ_TIMEOUT; 350 351 static void 352 in6_rtqtimo(void *rock) 353 { 354 struct radix_node_head *rnh = rock; 355 struct rtqk_arg arg; 356 struct timeval atv; 357 static time_t last_adjusted_timeout = 0; 358 int s; 359 360 arg.found = arg.killed = 0; 361 arg.rnh = rnh; 362 arg.nextstop = time_second + rtq_timeout; 363 arg.draining = arg.updating = 0; 364 s = splnet(); 365 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 366 splx(s); 367 368 /* 369 * Attempt to be somewhat dynamic about this: 370 * If there are ``too many'' routes sitting around taking up space, 371 * then crank down the timeout, and see if we can't make some more 372 * go away. However, we make sure that we will never adjust more 373 * than once in rtq_timeout seconds, to keep from cranking down too 374 * hard. 375 */ 376 if ((arg.found - arg.killed > rtq_toomany) 377 && (time_second - last_adjusted_timeout >= rtq_timeout) 378 && rtq_reallyold > rtq_minreallyold) { 379 rtq_reallyold = 2*rtq_reallyold / 3; 380 if (rtq_reallyold < rtq_minreallyold) { 381 rtq_reallyold = rtq_minreallyold; 382 } 383 384 last_adjusted_timeout = time_second; 385 #ifdef DIAGNOSTIC 386 log(LOG_DEBUG, "in6_rtqtimo: adjusted rtq_reallyold to %d", 387 rtq_reallyold); 388 #endif 389 arg.found = arg.killed = 0; 390 arg.updating = 1; 391 s = splnet(); 392 rnh->rnh_walktree(rnh, in6_rtqkill, &arg); 393 splx(s); 394 } 395 396 atv.tv_usec = 0; 397 atv.tv_sec = arg.nextstop; 398 timeout(in6_rtqtimo, rock, tvtohz(&atv)); 399 } 400 401 /* 402 * Age old PMTUs. 403 */ 404 struct mtuex_arg { 405 struct radix_node_head *rnh; 406 time_t nextstop; 407 }; 408 409 static int 410 in6_mtuexpire(struct radix_node *rn, void *rock) 411 { 412 struct rtentry *rt = (struct rtentry *)rn; 413 struct mtuex_arg *ap = rock; 414 415 /* sanity */ 416 if (!rt) 417 panic("rt == NULL in in6_mtuexpire"); 418 419 if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) { 420 if (rt->rt_rmx.rmx_expire <= time_second) { 421 rt->rt_flags |= RTF_PROBEMTU; 422 } else { 423 ap->nextstop = lmin(ap->nextstop, 424 rt->rt_rmx.rmx_expire); 425 } 426 } 427 428 return 0; 429 } 430 431 #define MTUTIMO_DEFAULT (60*1) 432 433 static void 434 in6_mtutimo(void *rock) 435 { 436 struct radix_node_head *rnh = rock; 437 struct mtuex_arg arg; 438 struct timeval atv; 439 int s; 440 441 arg.rnh = rnh; 442 arg.nextstop = time_second + MTUTIMO_DEFAULT; 443 s = splnet(); 444 rnh->rnh_walktree(rnh, in6_mtuexpire, &arg); 445 splx(s); 446 447 atv.tv_usec = 0; 448 atv.tv_sec = arg.nextstop; 449 if (atv.tv_sec < time_second) { 450 printf("invalid mtu expiration time on routing table\n"); 451 arg.nextstop = time_second + 30; /*last resort*/ 452 } 453 timeout(in6_mtutimo, rock, tvtohz(&atv)); 454 } 455 456 /* 457 * Initialize our routing tree. 458 */ 459 int 460 in6_inithead(void **head, int off) 461 { 462 struct radix_node_head *rnh; 463 464 if (!rn_inithead(head, off)) 465 return 0; 466 467 if (head != (void **)&rt_tables[AF_INET6]) /* BOGUS! */ 468 return 1; /* only do this for the real routing table */ 469 470 rnh = *head; 471 rnh->rnh_addaddr = in6_addroute; 472 rnh->rnh_matchaddr = in6_matroute; 473 rnh->rnh_close = in6_clsroute; 474 in6_rtqtimo(rnh); /* kick off timeout first time */ 475 in6_mtutimo(rnh); /* kick off timeout first time */ 476 return 1; 477 } 478