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 30 /* 31 * This code does two things necessary for the enhanced TCP metrics to 32 * function in a useful manner: 33 * 1) It marks all non-host routes as `cloning', thus ensuring that 34 * every actual reference to such a route actually gets turned 35 * into a reference to a host route to the specific destination 36 * requested. 37 * 2) When such routes lose all their references, it arranges for them 38 * to be deleted in some random collection of circumstances, so that 39 * a large quantity of stale routing data is not kept in kernel memory 40 * indefinitely. See in_rtqtimo() below for the exact mechanism. 41 */ 42 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD$"); 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/callout.h> 54 55 #include <net/if.h> 56 #include <net/route.h> 57 #include <net/vnet.h> 58 59 #include <netinet/in.h> 60 #include <netinet/in_var.h> 61 #include <netinet/ip_var.h> 62 63 extern int in_inithead(void **head, int off); 64 #ifdef VIMAGE 65 extern int in_detachhead(void **head, int off); 66 #endif 67 68 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */ 69 70 /* 71 * Do what we need to do when inserting a route. 72 */ 73 static struct radix_node * 74 in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head, 75 struct radix_node *treenodes) 76 { 77 struct rtentry *rt = (struct rtentry *)treenodes; 78 struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt); 79 80 RADIX_NODE_HEAD_WLOCK_ASSERT(head); 81 /* 82 * A little bit of help for both IP output and input: 83 * For host routes, we make sure that RTF_BROADCAST 84 * is set for anything that looks like a broadcast address. 85 * This way, we can avoid an expensive call to in_broadcast() 86 * in ip_output() most of the time (because the route passed 87 * to ip_output() is almost always a host route). 88 * 89 * We also do the same for local addresses, with the thought 90 * that this might one day be used to speed up ip_input(). 91 * 92 * We also mark routes to multicast addresses as such, because 93 * it's easy to do and might be useful (but this is much more 94 * dubious since it's so easy to inspect the address). 95 */ 96 if (rt->rt_flags & RTF_HOST) { 97 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) { 98 rt->rt_flags |= RTF_BROADCAST; 99 } else if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr == 100 sin->sin_addr.s_addr) { 101 rt->rt_flags |= RTF_LOCAL; 102 } 103 } 104 if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr))) 105 rt->rt_flags |= RTF_MULTICAST; 106 107 if (!rt->rt_rmx.rmx_mtu && rt->rt_ifp) 108 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; 109 110 return (rn_addroute(v_arg, n_arg, head, treenodes)); 111 } 112 113 /* 114 * This code is the inverse of in_clsroute: on first reference, if we 115 * were managing the route, stop doing so and set the expiration timer 116 * back off again. 117 */ 118 static struct radix_node * 119 in_matroute(void *v_arg, struct radix_node_head *head) 120 { 121 struct radix_node *rn = rn_match(v_arg, head); 122 struct rtentry *rt = (struct rtentry *)rn; 123 124 if (rt) { 125 RT_LOCK(rt); 126 if (rt->rt_flags & RTPRF_OURS) { 127 rt->rt_flags &= ~RTPRF_OURS; 128 rt->rt_rmx.rmx_expire = 0; 129 } 130 RT_UNLOCK(rt); 131 } 132 return rn; 133 } 134 135 static VNET_DEFINE(int, rtq_reallyold) = 60*60; /* one hour is "really old" */ 136 #define V_rtq_reallyold VNET(rtq_reallyold) 137 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW, 138 &VNET_NAME(rtq_reallyold), 0, 139 "Default expiration time on dynamically learned routes"); 140 141 /* never automatically crank down to less */ 142 static VNET_DEFINE(int, rtq_minreallyold) = 10; 143 #define V_rtq_minreallyold VNET(rtq_minreallyold) 144 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW, 145 &VNET_NAME(rtq_minreallyold), 0, 146 "Minimum time to attempt to hold onto dynamically learned routes"); 147 148 /* 128 cached routes is "too many" */ 149 static VNET_DEFINE(int, rtq_toomany) = 128; 150 #define V_rtq_toomany VNET(rtq_toomany) 151 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW, 152 &VNET_NAME(rtq_toomany), 0, 153 "Upper limit on dynamically learned routes"); 154 155 /* 156 * On last reference drop, mark the route as belong to us so that it can be 157 * timed out. 158 */ 159 static void 160 in_clsroute(struct radix_node *rn, struct radix_node_head *head) 161 { 162 struct rtentry *rt = (struct rtentry *)rn; 163 164 RT_LOCK_ASSERT(rt); 165 166 if (!(rt->rt_flags & RTF_UP)) 167 return; /* prophylactic measures */ 168 169 if (rt->rt_flags & RTPRF_OURS) 170 return; 171 172 if (!(rt->rt_flags & RTF_DYNAMIC)) 173 return; 174 175 /* 176 * If rtq_reallyold is 0, just delete the route without 177 * waiting for a timeout cycle to kill it. 178 */ 179 if (V_rtq_reallyold != 0) { 180 rt->rt_flags |= RTPRF_OURS; 181 rt->rt_rmx.rmx_expire = time_uptime + V_rtq_reallyold; 182 } else { 183 rtexpunge(rt); 184 } 185 } 186 187 struct rtqk_arg { 188 struct radix_node_head *rnh; 189 int draining; 190 int killed; 191 int found; 192 int updating; 193 time_t nextstop; 194 }; 195 196 /* 197 * Get rid of old routes. When draining, this deletes everything, even when 198 * the timeout is not expired yet. When updating, this makes sure that 199 * nothing has a timeout longer than the current value of rtq_reallyold. 200 */ 201 static int 202 in_rtqkill(struct radix_node *rn, void *rock) 203 { 204 struct rtqk_arg *ap = rock; 205 struct rtentry *rt = (struct rtentry *)rn; 206 int err; 207 208 RADIX_NODE_HEAD_WLOCK_ASSERT(ap->rnh); 209 210 if (rt->rt_flags & RTPRF_OURS) { 211 ap->found++; 212 213 if (ap->draining || rt->rt_rmx.rmx_expire <= time_uptime) { 214 if (rt->rt_refcnt > 0) 215 panic("rtqkill route really not free"); 216 217 err = in_rtrequest(RTM_DELETE, 218 (struct sockaddr *)rt_key(rt), 219 rt->rt_gateway, rt_mask(rt), 220 rt->rt_flags | RTF_RNH_LOCKED, 0, 221 rt->rt_fibnum); 222 if (err) { 223 log(LOG_WARNING, "in_rtqkill: error %d\n", err); 224 } else { 225 ap->killed++; 226 } 227 } else { 228 if (ap->updating && 229 (rt->rt_rmx.rmx_expire - time_uptime > 230 V_rtq_reallyold)) { 231 rt->rt_rmx.rmx_expire = 232 time_uptime + V_rtq_reallyold; 233 } 234 ap->nextstop = lmin(ap->nextstop, 235 rt->rt_rmx.rmx_expire); 236 } 237 } 238 239 return 0; 240 } 241 242 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */ 243 static VNET_DEFINE(int, rtq_timeout) = RTQ_TIMEOUT; 244 static VNET_DEFINE(struct callout, rtq_timer); 245 246 #define V_rtq_timeout VNET(rtq_timeout) 247 #define V_rtq_timer VNET(rtq_timer) 248 249 static void in_rtqtimo_one(void *rock); 250 251 static void 252 in_rtqtimo(void *rock) 253 { 254 CURVNET_SET((struct vnet *) rock); 255 int fibnum; 256 void *newrock; 257 struct timeval atv; 258 259 for (fibnum = 0; fibnum < rt_numfibs; fibnum++) { 260 newrock = rt_tables_get_rnh(fibnum, AF_INET); 261 if (newrock != NULL) 262 in_rtqtimo_one(newrock); 263 } 264 atv.tv_usec = 0; 265 atv.tv_sec = V_rtq_timeout; 266 callout_reset(&V_rtq_timer, tvtohz(&atv), in_rtqtimo, rock); 267 CURVNET_RESTORE(); 268 } 269 270 static void 271 in_rtqtimo_one(void *rock) 272 { 273 struct radix_node_head *rnh = rock; 274 struct rtqk_arg arg; 275 static time_t last_adjusted_timeout = 0; 276 277 arg.found = arg.killed = 0; 278 arg.rnh = rnh; 279 arg.nextstop = time_uptime + V_rtq_timeout; 280 arg.draining = arg.updating = 0; 281 RADIX_NODE_HEAD_LOCK(rnh); 282 rnh->rnh_walktree(rnh, in_rtqkill, &arg); 283 RADIX_NODE_HEAD_UNLOCK(rnh); 284 285 /* 286 * Attempt to be somewhat dynamic about this: 287 * If there are ``too many'' routes sitting around taking up space, 288 * then crank down the timeout, and see if we can't make some more 289 * go away. However, we make sure that we will never adjust more 290 * than once in rtq_timeout seconds, to keep from cranking down too 291 * hard. 292 */ 293 if ((arg.found - arg.killed > V_rtq_toomany) && 294 (time_uptime - last_adjusted_timeout >= V_rtq_timeout) && 295 V_rtq_reallyold > V_rtq_minreallyold) { 296 V_rtq_reallyold = 2 * V_rtq_reallyold / 3; 297 if (V_rtq_reallyold < V_rtq_minreallyold) { 298 V_rtq_reallyold = V_rtq_minreallyold; 299 } 300 301 last_adjusted_timeout = time_uptime; 302 #ifdef DIAGNOSTIC 303 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n", 304 V_rtq_reallyold); 305 #endif 306 arg.found = arg.killed = 0; 307 arg.updating = 1; 308 RADIX_NODE_HEAD_LOCK(rnh); 309 rnh->rnh_walktree(rnh, in_rtqkill, &arg); 310 RADIX_NODE_HEAD_UNLOCK(rnh); 311 } 312 313 } 314 315 void 316 in_rtqdrain(void) 317 { 318 VNET_ITERATOR_DECL(vnet_iter); 319 struct radix_node_head *rnh; 320 struct rtqk_arg arg; 321 int fibnum; 322 323 VNET_LIST_RLOCK_NOSLEEP(); 324 VNET_FOREACH(vnet_iter) { 325 CURVNET_SET(vnet_iter); 326 327 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) { 328 rnh = rt_tables_get_rnh(fibnum, AF_INET); 329 arg.found = arg.killed = 0; 330 arg.rnh = rnh; 331 arg.nextstop = 0; 332 arg.draining = 1; 333 arg.updating = 0; 334 RADIX_NODE_HEAD_LOCK(rnh); 335 rnh->rnh_walktree(rnh, in_rtqkill, &arg); 336 RADIX_NODE_HEAD_UNLOCK(rnh); 337 } 338 CURVNET_RESTORE(); 339 } 340 VNET_LIST_RUNLOCK_NOSLEEP(); 341 } 342 343 static int _in_rt_was_here; 344 /* 345 * Initialize our routing tree. 346 */ 347 int 348 in_inithead(void **head, int off) 349 { 350 struct radix_node_head *rnh; 351 352 /* XXX MRT 353 * This can be called from vfs_export.c too in which case 'off' 354 * will be 0. We know the correct value so just use that and 355 * return directly if it was 0. 356 * This is a hack that replaces an even worse hack on a bad hack 357 * on a bad design. After RELENG_7 this should be fixed but that 358 * will change the ABI, so for now do it this way. 359 */ 360 if (!rn_inithead(head, 32)) 361 return 0; 362 363 if (off == 0) /* XXX MRT see above */ 364 return 1; /* only do the rest for a real routing table */ 365 366 rnh = *head; 367 rnh->rnh_addaddr = in_addroute; 368 rnh->rnh_matchaddr = in_matroute; 369 rnh->rnh_close = in_clsroute; 370 if (_in_rt_was_here == 0 ) { 371 callout_init(&V_rtq_timer, CALLOUT_MPSAFE); 372 callout_reset(&V_rtq_timer, 1, in_rtqtimo, curvnet); 373 _in_rt_was_here = 1; 374 } 375 return 1; 376 } 377 378 #ifdef VIMAGE 379 int 380 in_detachhead(void **head, int off) 381 { 382 383 callout_drain(&V_rtq_timer); 384 return (1); 385 } 386 #endif 387 388 /* 389 * This zaps old routes when the interface goes down or interface 390 * address is deleted. In the latter case, it deletes static routes 391 * that point to this address. If we don't do this, we may end up 392 * using the old address in the future. The ones we always want to 393 * get rid of are things like ARP entries, since the user might down 394 * the interface, walk over to a completely different network, and 395 * plug back in. 396 */ 397 struct in_ifadown_arg { 398 struct ifaddr *ifa; 399 int del; 400 }; 401 402 static int 403 in_ifadownkill(struct radix_node *rn, void *xap) 404 { 405 struct in_ifadown_arg *ap = xap; 406 struct rtentry *rt = (struct rtentry *)rn; 407 408 RT_LOCK(rt); 409 if (rt->rt_ifa == ap->ifa && 410 (ap->del || !(rt->rt_flags & RTF_STATIC))) { 411 /* 412 * Aquire a reference so that it can later be freed 413 * as the refcount would be 0 here in case of at least 414 * ap->del. 415 */ 416 RT_ADDREF(rt); 417 /* 418 * Disconnect it from the tree and permit protocols 419 * to cleanup. 420 */ 421 rtexpunge(rt); 422 /* 423 * At this point it is an rttrash node, and in case 424 * the above is the only reference we must free it. 425 * If we do not noone will have a pointer and the 426 * rtentry will be leaked forever. 427 * In case someone else holds a reference, we are 428 * fine as we only decrement the refcount. In that 429 * case if the other entity calls RT_REMREF, we 430 * will still be leaking but at least we tried. 431 */ 432 RTFREE_LOCKED(rt); 433 return (0); 434 } 435 RT_UNLOCK(rt); 436 return 0; 437 } 438 439 int 440 in_ifadown(struct ifaddr *ifa, int delete) 441 { 442 struct in_ifadown_arg arg; 443 struct radix_node_head *rnh; 444 int fibnum; 445 446 if (ifa->ifa_addr->sa_family != AF_INET) 447 return 1; 448 449 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) { 450 rnh = rt_tables_get_rnh(fibnum, AF_INET); 451 arg.ifa = ifa; 452 arg.del = delete; 453 RADIX_NODE_HEAD_LOCK(rnh); 454 rnh->rnh_walktree(rnh, in_ifadownkill, &arg); 455 RADIX_NODE_HEAD_UNLOCK(rnh); 456 ifa->ifa_flags &= ~IFA_ROUTE; /* XXXlocking? */ 457 } 458 return 0; 459 } 460 461 /* 462 * inet versions of rt functions. These have fib extensions and 463 * for now will just reference the _fib variants. 464 * eventually this order will be reversed, 465 */ 466 void 467 in_rtalloc_ign(struct route *ro, u_long ignflags, u_int fibnum) 468 { 469 rtalloc_ign_fib(ro, ignflags, fibnum); 470 } 471 472 int 473 in_rtrequest( int req, 474 struct sockaddr *dst, 475 struct sockaddr *gateway, 476 struct sockaddr *netmask, 477 int flags, 478 struct rtentry **ret_nrt, 479 u_int fibnum) 480 { 481 return (rtrequest_fib(req, dst, gateway, netmask, 482 flags, ret_nrt, fibnum)); 483 } 484 485 struct rtentry * 486 in_rtalloc1(struct sockaddr *dst, int report, u_long ignflags, u_int fibnum) 487 { 488 return (rtalloc1_fib(dst, report, ignflags, fibnum)); 489 } 490 491 void 492 in_rtredirect(struct sockaddr *dst, 493 struct sockaddr *gateway, 494 struct sockaddr *netmask, 495 int flags, 496 struct sockaddr *src, 497 u_int fibnum) 498 { 499 rtredirect_fib(dst, gateway, netmask, flags, src, fibnum); 500 } 501 502 void 503 in_rtalloc(struct route *ro, u_int fibnum) 504 { 505 rtalloc_ign_fib(ro, 0UL, fibnum); 506 } 507 508 #if 0 509 int in_rt_getifa(struct rt_addrinfo *, u_int fibnum); 510 int in_rtioctl(u_long, caddr_t, u_int); 511 int in_rtrequest1(int, struct rt_addrinfo *, struct rtentry **, u_int); 512 #endif 513 514 515