1 /* 2 * Copyright 1994, 1995 Massachusetts Institute of Technology 3 * 4 * Permission to use, copy, modify, and distribute this software and 5 * its documentation for any purpose and without fee is hereby 6 * granted, provided that both the above copyright notice and this 7 * permission notice appear in all copies, that both the above 8 * copyright notice and this permission notice appear in all 9 * supporting documentation, and that the name of M.I.T. not be used 10 * in advertising or publicity pertaining to distribution of the 11 * software without specific, written prior permission. M.I.T. makes 12 * no representations about the suitability of this software for any 13 * purpose. It is provided "as is" without express or implied 14 * warranty. 15 * 16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS 17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, 18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD: src/sys/netinet/in_rmx.c,v 1.37.2.3 2002/08/09 14:49:23 ru Exp $ 30 * $DragonFly: src/sys/netinet/in_rmx.c,v 1.12 2005/06/02 23:52:42 dillon Exp $ 31 */ 32 33 /* 34 * This code does two things necessary for the enhanced TCP metrics to 35 * function in a useful manner: 36 * 1) It marks all non-host routes as `cloning', thus ensuring that 37 * every actual reference to such a route actually gets turned 38 * into a reference to a host route to the specific destination 39 * requested. 40 * 2) When such routes lose all their references, it arranges for them 41 * to be deleted in some random collection of circumstances, so that 42 * a large quantity of stale routing data is not kept in kernel memory 43 * indefinitely. See in_rtqtimo() below for the exact mechanism. 44 */ 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/kernel.h> 49 #include <sys/sysctl.h> 50 #include <sys/socket.h> 51 #include <sys/mbuf.h> 52 #include <sys/syslog.h> 53 #include <sys/thread2.h> 54 55 #include <net/if.h> 56 #include <net/route.h> 57 #include <netinet/in.h> 58 #include <netinet/in_var.h> 59 #include <netinet/ip_var.h> 60 61 #define RTPRF_EXPIRING RTF_PROTO3 /* set on routes we manage */ 62 63 static struct callout in_rtqtimo_ch; 64 65 /* 66 * Do what we need to do when inserting a route. 67 */ 68 static struct radix_node * 69 in_addroute(char *key, char *mask, struct radix_node_head *head, 70 struct radix_node *treenodes) 71 { 72 struct rtentry *rt = (struct rtentry *)treenodes; 73 struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt); 74 struct radix_node *ret; 75 76 /* 77 * For IP, all unicast non-host routes are automatically cloning. 78 */ 79 if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr))) 80 rt->rt_flags |= RTF_MULTICAST; 81 82 if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) 83 rt->rt_flags |= RTF_PRCLONING; 84 85 /* 86 * A little bit of help for both IP output and input: 87 * For host routes, we make sure that RTF_BROADCAST 88 * is set for anything that looks like a broadcast address. 89 * This way, we can avoid an expensive call to in_broadcast() 90 * in ip_output() most of the time (because the route passed 91 * to ip_output() is almost always a host route). 92 * 93 * We also do the same for local addresses, with the thought 94 * that this might one day be used to speed up ip_input(). 95 * 96 * We also mark routes to multicast addresses as such, because 97 * it's easy to do and might be useful (but this is much more 98 * dubious since it's so easy to inspect the address). (This 99 * is done above.) 100 */ 101 if (rt->rt_flags & RTF_HOST) { 102 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) { 103 rt->rt_flags |= RTF_BROADCAST; 104 } else { 105 if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr 106 == sin->sin_addr.s_addr) 107 rt->rt_flags |= RTF_LOCAL; 108 } 109 } 110 111 if (rt->rt_rmx.rmx_mtu != 0 && !(rt->rt_rmx.rmx_locks & RTV_MTU) && 112 rt->rt_ifp != NULL) 113 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; 114 115 ret = rn_addroute(key, mask, head, treenodes); 116 if (ret == NULL && rt->rt_flags & RTF_HOST) { 117 struct rtentry *oldrt; 118 119 /* 120 * We are trying to add a host route, but can't. 121 * Find out if it is because of an ARP entry and 122 * delete it if so. 123 */ 124 oldrt = rtpurelookup((struct sockaddr *)sin); 125 if (oldrt != NULL) { 126 --oldrt->rt_refcnt; 127 if (oldrt->rt_flags & RTF_LLINFO && 128 oldrt->rt_flags & RTF_HOST && 129 oldrt->rt_gateway && 130 oldrt->rt_gateway->sa_family == AF_LINK) { 131 rtrequest(RTM_DELETE, rt_key(oldrt), 132 oldrt->rt_gateway, rt_mask(oldrt), 133 oldrt->rt_flags, NULL); 134 ret = rn_addroute(key, mask, head, treenodes); 135 } 136 } 137 } 138 139 /* 140 * If the new route created successfully, and we are forwarding, 141 * and there is a cached route, free it. Otherwise, we may end 142 * up using the wrong route. 143 */ 144 if (ret != NULL && ipforwarding && ipforward_rt.ro_rt != NULL) { 145 RTFREE(ipforward_rt.ro_rt); 146 ipforward_rt.ro_rt = NULL; 147 } 148 149 return ret; 150 } 151 152 /* 153 * This code is the inverse of in_closeroute: on first reference, if we 154 * were managing the route, stop doing so and set the expiration timer 155 * back off again. 156 */ 157 static struct radix_node * 158 in_matchroute(char *key, struct radix_node_head *head) 159 { 160 struct radix_node *rn = rn_match(key, head); 161 struct rtentry *rt = (struct rtentry *)rn; 162 163 if (rt != NULL && rt->rt_refcnt == 0) { /* this is first reference */ 164 if (rt->rt_flags & RTPRF_EXPIRING) { 165 rt->rt_flags &= ~RTPRF_EXPIRING; 166 rt->rt_rmx.rmx_expire = 0; 167 } 168 } 169 return rn; 170 } 171 172 static int rtq_reallyold = 60*60; /* one hour is ``really old'' */ 173 SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW, 174 &rtq_reallyold , 0, 175 "Default expiration time on cloned routes"); 176 177 static int rtq_minreallyold = 10; /* never automatically crank down to less */ 178 SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW, 179 &rtq_minreallyold , 0, 180 "Minimum time to attempt to hold onto cloned routes"); 181 182 static int rtq_toomany = 128; /* 128 cached routes is ``too many'' */ 183 SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW, 184 &rtq_toomany , 0, "Upper limit on cloned routes"); 185 186 /* 187 * On last reference drop, mark the route as belong to us so that it can be 188 * timed out. 189 */ 190 static void 191 in_closeroute(struct radix_node *rn, struct radix_node_head *head) 192 { 193 struct rtentry *rt = (struct rtentry *)rn; 194 195 if (!(rt->rt_flags & RTF_UP)) 196 return; /* prophylactic measures */ 197 198 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST) 199 return; 200 201 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_EXPIRING)) != RTF_WASCLONED) 202 return; 203 204 /* 205 * As requested by David Greenman: 206 * If rtq_reallyold is 0, just delete the route without 207 * waiting for a timeout cycle to kill it. 208 */ 209 if (rtq_reallyold != 0) { 210 rt->rt_flags |= RTPRF_EXPIRING; 211 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold; 212 } else { 213 /* 214 * Remove route from the radix tree, but defer deallocation 215 * until we return to rtfree(). 216 */ 217 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt), 218 rt->rt_flags, &rt); 219 } 220 } 221 222 struct rtqk_arg { 223 struct radix_node_head *rnh; 224 int draining; 225 int killed; 226 int found; 227 int updating; 228 time_t nextstop; 229 }; 230 231 /* 232 * Get rid of old routes. When draining, this deletes everything, even when 233 * the timeout is not expired yet. When updating, this makes sure that 234 * nothing has a timeout longer than the current value of rtq_reallyold. 235 */ 236 static int 237 in_rtqkill(struct radix_node *rn, void *rock) 238 { 239 struct rtqk_arg *ap = rock; 240 struct rtentry *rt = (struct rtentry *)rn; 241 int err; 242 243 if (rt->rt_flags & RTPRF_EXPIRING) { 244 ap->found++; 245 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) { 246 if (rt->rt_refcnt > 0) 247 panic("rtqkill route really not free"); 248 249 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 250 rt_mask(rt), rt->rt_flags, NULL); 251 if (err) 252 log(LOG_WARNING, "in_rtqkill: error %d\n", err); 253 else 254 ap->killed++; 255 } else { 256 if (ap->updating && 257 (rt->rt_rmx.rmx_expire - time_second > 258 rtq_reallyold)) { 259 rt->rt_rmx.rmx_expire = time_second + 260 rtq_reallyold; 261 } 262 ap->nextstop = lmin(ap->nextstop, 263 rt->rt_rmx.rmx_expire); 264 } 265 } 266 267 return 0; 268 } 269 270 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */ 271 static int rtq_timeout = RTQ_TIMEOUT; 272 273 static void 274 in_rtqtimo(void *rock) 275 { 276 struct radix_node_head *rnh = rock; 277 struct rtqk_arg arg; 278 struct timeval atv; 279 static time_t last_adjusted_timeout = 0; 280 281 arg.found = arg.killed = 0; 282 arg.rnh = rnh; 283 arg.nextstop = time_second + rtq_timeout; 284 arg.draining = arg.updating = 0; 285 crit_enter(); 286 rnh->rnh_walktree(rnh, in_rtqkill, &arg); 287 crit_exit(); 288 289 /* 290 * Attempt to be somewhat dynamic about this: 291 * If there are ``too many'' routes sitting around taking up space, 292 * then crank down the timeout, and see if we can't make some more 293 * go away. However, we make sure that we will never adjust more 294 * than once in rtq_timeout seconds, to keep from cranking down too 295 * hard. 296 */ 297 if ((arg.found - arg.killed > rtq_toomany) && 298 (time_second - last_adjusted_timeout >= rtq_timeout) && 299 rtq_reallyold > rtq_minreallyold) { 300 rtq_reallyold = 2*rtq_reallyold / 3; 301 if (rtq_reallyold < rtq_minreallyold) { 302 rtq_reallyold = rtq_minreallyold; 303 } 304 305 last_adjusted_timeout = time_second; 306 #ifdef DIAGNOSTIC 307 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n", 308 rtq_reallyold); 309 #endif 310 arg.found = arg.killed = 0; 311 arg.updating = 1; 312 crit_enter(); 313 rnh->rnh_walktree(rnh, in_rtqkill, &arg); 314 crit_exit(); 315 } 316 317 atv.tv_usec = 0; 318 atv.tv_sec = arg.nextstop - time_second; 319 callout_reset(&in_rtqtimo_ch, tvtohz_high(&atv), in_rtqtimo, rock); 320 } 321 322 void 323 in_rtqdrain(void) 324 { 325 struct radix_node_head *rnh = rt_tables[AF_INET]; 326 struct rtqk_arg arg; 327 328 arg.found = arg.killed = 0; 329 arg.rnh = rnh; 330 arg.nextstop = 0; 331 arg.draining = 1; 332 arg.updating = 0; 333 crit_enter(); 334 rnh->rnh_walktree(rnh, in_rtqkill, &arg); 335 crit_exit(); 336 } 337 338 /* 339 * Initialize our routing tree. 340 */ 341 int 342 in_inithead(void **head, int off) 343 { 344 struct radix_node_head *rnh; 345 346 if (!rn_inithead(head, off)) 347 return 0; 348 349 if (head != (void **)&rt_tables[AF_INET]) /* BOGUS! */ 350 return 1; /* only do this for the real routing table */ 351 352 rnh = *head; 353 rnh->rnh_addaddr = in_addroute; 354 rnh->rnh_matchaddr = in_matchroute; 355 rnh->rnh_close = in_closeroute; 356 callout_init(&in_rtqtimo_ch); 357 in_rtqtimo(rnh); /* kick off timeout first time */ 358 return 1; 359 } 360 361 /* 362 * This zaps old routes when the interface goes down or interface 363 * address is deleted. In the latter case, it deletes static routes 364 * that point to this address. If we don't do this, we may end up 365 * using the old address in the future. The ones we always want to 366 * get rid of are things like ARP entries, since the user might down 367 * the interface, walk over to a completely different network, and 368 * plug back in. 369 */ 370 struct in_ifadown_arg { 371 struct radix_node_head *rnh; 372 struct ifaddr *ifa; 373 int del; 374 }; 375 376 static int 377 in_ifadownkill(struct radix_node *rn, void *xap) 378 { 379 struct in_ifadown_arg *ap = xap; 380 struct rtentry *rt = (struct rtentry *)rn; 381 int err; 382 383 if (rt->rt_ifa == ap->ifa && 384 (ap->del || !(rt->rt_flags & RTF_STATIC))) { 385 /* 386 * We need to disable the automatic prune that happens 387 * in this case in rtrequest() because it will blow 388 * away the pointers that rn_walktree() needs in order 389 * continue our descent. We will end up deleting all 390 * the routes that rtrequest() would have in any case, 391 * so that behavior is not needed there. 392 */ 393 rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING); 394 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 395 rt_mask(rt), rt->rt_flags, NULL); 396 if (err) 397 log(LOG_WARNING, "in_ifadownkill: error %d\n", err); 398 } 399 return 0; 400 } 401 402 int 403 in_ifadown(struct ifaddr *ifa, int delete) 404 { 405 struct in_ifadown_arg arg; 406 struct radix_node_head *rnh; 407 408 if (ifa->ifa_addr->sa_family != AF_INET) 409 return 1; 410 411 arg.rnh = rnh = rt_tables[AF_INET]; 412 arg.ifa = ifa; 413 arg.del = delete; 414 rnh->rnh_walktree(rnh, in_ifadownkill, &arg); 415 ifa->ifa_flags &= ~IFA_ROUTE; 416 return 0; 417 } 418