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 * $KAME: in6_rmx.c,v 1.11 2001/07/26 06:53:16 jinmei Exp $
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 */
61
62 /*
63 * This code does two things necessary for the enhanced TCP metrics to
64 * function in a useful manner:
65 * 1) It marks all non-host routes as `cloning', thus ensuring that
66 * every actual reference to such a route actually gets turned
67 * into a reference to a host route to the specific destination
68 * requested.
69 * 2) When such routes lose all their references, it arranges for them
70 * to be deleted in some random collection of circumstances, so that
71 * a large quantity of stale routing data is not kept in kernel memory
72 * indefinitely. See in6_rtqtimo() below for the exact mechanism.
73 */
74
75 #include <sys/cdefs.h>
76 __FBSDID("$FreeBSD$");
77
78 #include <sys/param.h>
79 #include <sys/systm.h>
80 #include <sys/kernel.h>
81 #include <sys/sysctl.h>
82 #include <sys/queue.h>
83 #include <sys/socket.h>
84 #include <sys/socketvar.h>
85 #include <sys/mbuf.h>
86 #include <sys/syslog.h>
87 #include <sys/callout.h>
88
89 #include <net/if.h>
90 #include <net/route.h>
91 #include <netinet/in.h>
92 #include <netinet/ip_var.h>
93 #include <netinet/in_var.h>
94
95 #include <netinet/ip6.h>
96 #include <netinet6/ip6_var.h>
97
98 #include <netinet/icmp6.h>
99 #include <netinet6/nd6.h>
100
101 #include <netinet/tcp.h>
102 #include <netinet/tcp_seq.h>
103 #include <netinet/tcp_timer.h>
104 #include <netinet/tcp_var.h>
105
106 extern int in6_inithead(void **head, int off);
107
108 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */
109
110 /*
111 * Do what we need to do when inserting a route.
112 */
113 static struct radix_node *
114 in6_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
115 struct radix_node *treenodes)
116 {
117 struct rtentry *rt = (struct rtentry *)treenodes;
118 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)rt_key(rt);
119 struct radix_node *ret;
120
121 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
122 rt->rt_flags |= RTF_MULTICAST;
123
124 /*
125 * A little bit of help for both IPv6 output and input:
126 * For local addresses, we make sure that RTF_LOCAL is set,
127 * with the thought that this might one day be used to speed up
128 * ip_input().
129 *
130 * We also mark routes to multicast addresses as such, because
131 * it's easy to do and might be useful (but this is much more
132 * dubious since it's so easy to inspect the address). (This
133 * is done above.)
134 *
135 * XXX
136 * should elaborate the code.
137 */
138 if (rt->rt_flags & RTF_HOST) {
139 if (IN6_ARE_ADDR_EQUAL(&satosin6(rt->rt_ifa->ifa_addr)
140 ->sin6_addr,
141 &sin6->sin6_addr)) {
142 rt->rt_flags |= RTF_LOCAL;
143 }
144 }
145
146 if (!rt->rt_rmx.rmx_mtu && rt->rt_ifp)
147 rt->rt_rmx.rmx_mtu = IN6_LINKMTU(rt->rt_ifp);
148
149 ret = rn_addroute(v_arg, n_arg, head, treenodes);
150 if (ret == NULL && rt->rt_flags & RTF_HOST) {
151 struct rtentry *rt2;
152 /*
153 * We are trying to add a host route, but can't.
154 * Find out if it is because of an
155 * ARP entry and delete it if so.
156 */
157 rt2 = rtalloc1((struct sockaddr *)sin6, 0, RTF_CLONING);
158 if (rt2) {
159 if (rt2->rt_flags & RTF_LLINFO &&
160 rt2->rt_flags & RTF_HOST &&
161 rt2->rt_gateway &&
162 rt2->rt_gateway->sa_family == AF_LINK) {
163 rtexpunge(rt2);
164 RTFREE_LOCKED(rt2);
165 ret = rn_addroute(v_arg, n_arg, head,
166 treenodes);
167 } else
168 RTFREE_LOCKED(rt2);
169 }
170 } else if (ret == NULL && rt->rt_flags & RTF_CLONING) {
171 struct rtentry *rt2;
172 /*
173 * We are trying to add a net route, but can't.
174 * The following case should be allowed, so we'll make a
175 * special check for this:
176 * Two IPv6 addresses with the same prefix is assigned
177 * to a single interrface.
178 * # ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1)
179 * # ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2)
180 * In this case, (*1) and (*2) want to add the same
181 * net route entry, 3ffe:0501:: -> if0.
182 * This case should not raise an error.
183 */
184 rt2 = rtalloc1((struct sockaddr *)sin6, 0, RTF_CLONING);
185 if (rt2) {
186 if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY))
187 == RTF_CLONING
188 && rt2->rt_gateway
189 && rt2->rt_gateway->sa_family == AF_LINK
190 && rt2->rt_ifp == rt->rt_ifp) {
191 ret = rt2->rt_nodes;
192 }
193 RTFREE_LOCKED(rt2);
194 }
195 }
196 return ret;
197 }
198
199 /*
200 * This code is the inverse of in6_clsroute: on first reference, if we
201 * were managing the route, stop doing so and set the expiration timer
202 * back off again.
203 */
204 static struct radix_node *
205 in6_matroute(void *v_arg, struct radix_node_head *head)
206 {
207 struct radix_node *rn = rn_match(v_arg, head);
208 struct rtentry *rt = (struct rtentry *)rn;
209
210 if (rt && rt->rt_refcnt == 0) { /* this is first reference */
211 if (rt->rt_flags & RTPRF_OURS) {
212 rt->rt_flags &= ~RTPRF_OURS;
213 rt->rt_rmx.rmx_expire = 0;
214 }
215 }
216 return rn;
217 }
218
219 SYSCTL_DECL(_net_inet6_ip6);
220
221 static int rtq_reallyold = 60*60;
222 /* one hour is ``really old'' */
223 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTEXPIRE, rtexpire,
224 CTLFLAG_RW, &rtq_reallyold , 0, "");
225
226 static int rtq_minreallyold = 10;
227 /* never automatically crank down to less */
228 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMINEXPIRE, rtminexpire,
229 CTLFLAG_RW, &rtq_minreallyold , 0, "");
230
231 static int rtq_toomany = 128;
232 /* 128 cached routes is ``too many'' */
233 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMAXCACHE, rtmaxcache,
234 CTLFLAG_RW, &rtq_toomany , 0, "");
235
236
237 /*
238 * On last reference drop, mark the route as belong to us so that it can be
239 * timed out.
240 */
241 static void
242 in6_clsroute(struct radix_node *rn, struct radix_node_head *head)
243 {
244 struct rtentry *rt = (struct rtentry *)rn;
245
246 RT_LOCK_ASSERT(rt);
247
248 if (!(rt->rt_flags & RTF_UP))
249 return; /* prophylactic measures */
250
251 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
252 return;
253
254 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS)) != RTF_WASCLONED)
255 return;
256
257 /*
258 * As requested by David Greenman:
259 * If rtq_reallyold is 0, just delete the route without
260 * waiting for a timeout cycle to kill it.
261 */
262 if (rtq_reallyold != 0) {
263 rt->rt_flags |= RTPRF_OURS;
264 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
265 } else {
266 rtexpunge(rt);
267 }
268 }
269
270 struct rtqk_arg {
271 struct radix_node_head *rnh;
272 int mode;
273 int updating;
274 int draining;
275 int killed;
276 int found;
277 time_t nextstop;
278 };
279
280 /*
281 * Get rid of old routes. When draining, this deletes everything, even when
282 * the timeout is not expired yet. When updating, this makes sure that
283 * nothing has a timeout longer than the current value of rtq_reallyold.
284 */
285 static int
286 in6_rtqkill(struct radix_node *rn, void *rock)
287 {
288 struct rtqk_arg *ap = rock;
289 struct rtentry *rt = (struct rtentry *)rn;
290 int err;
291
292 if (rt->rt_flags & RTPRF_OURS) {
293 ap->found++;
294
295 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) {
296 if (rt->rt_refcnt > 0)
297 panic("rtqkill route really not free");
298
299 err = rtrequest(RTM_DELETE,
300 (struct sockaddr *)rt_key(rt),
301 rt->rt_gateway, rt_mask(rt),
302 rt->rt_flags, 0);
303 if (err) {
304 log(LOG_WARNING, "in6_rtqkill: error %d", err);
305 } else {
306 ap->killed++;
307 }
308 } else {
309 if (ap->updating
310 && (rt->rt_rmx.rmx_expire - time_second
311 > rtq_reallyold)) {
312 rt->rt_rmx.rmx_expire = time_second
313 + rtq_reallyold;
314 }
315 ap->nextstop = lmin(ap->nextstop,
316 rt->rt_rmx.rmx_expire);
317 }
318 }
319
320 return 0;
321 }
322
323 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
324 static int rtq_timeout = RTQ_TIMEOUT;
325 static struct callout rtq_timer;
326
327 static void
328 in6_rtqtimo(void *rock)
329 {
330 struct radix_node_head *rnh = rock;
331 struct rtqk_arg arg;
332 struct timeval atv;
333 static time_t last_adjusted_timeout = 0;
334
335 arg.found = arg.killed = 0;
336 arg.rnh = rnh;
337 arg.nextstop = time_second + rtq_timeout;
338 arg.draining = arg.updating = 0;
339 RADIX_NODE_HEAD_LOCK(rnh);
340 rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
341 RADIX_NODE_HEAD_UNLOCK(rnh);
342
343 /*
344 * Attempt to be somewhat dynamic about this:
345 * If there are ``too many'' routes sitting around taking up space,
346 * then crank down the timeout, and see if we can't make some more
347 * go away. However, we make sure that we will never adjust more
348 * than once in rtq_timeout seconds, to keep from cranking down too
349 * hard.
350 */
351 if ((arg.found - arg.killed > rtq_toomany)
352 && (time_second - last_adjusted_timeout >= rtq_timeout)
353 && rtq_reallyold > rtq_minreallyold) {
354 rtq_reallyold = 2*rtq_reallyold / 3;
355 if (rtq_reallyold < rtq_minreallyold) {
356 rtq_reallyold = rtq_minreallyold;
357 }
358
359 last_adjusted_timeout = time_second;
360 #ifdef DIAGNOSTIC
361 log(LOG_DEBUG, "in6_rtqtimo: adjusted rtq_reallyold to %d",
362 rtq_reallyold);
363 #endif
364 arg.found = arg.killed = 0;
365 arg.updating = 1;
366 RADIX_NODE_HEAD_LOCK(rnh);
367 rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
368 RADIX_NODE_HEAD_UNLOCK(rnh);
369 }
370
371 atv.tv_usec = 0;
372 atv.tv_sec = arg.nextstop - time_second;
373 callout_reset(&rtq_timer, tvtohz(&atv), in6_rtqtimo, rock);
374 }
375
376 /*
377 * Age old PMTUs.
378 */
379 struct mtuex_arg {
380 struct radix_node_head *rnh;
381 time_t nextstop;
382 };
383 static struct callout rtq_mtutimer;
384
385 static int
386 in6_mtuexpire(struct radix_node *rn, void *rock)
387 {
388 struct rtentry *rt = (struct rtentry *)rn;
389 struct mtuex_arg *ap = rock;
390
391 /* sanity */
392 if (!rt)
393 panic("rt == NULL in in6_mtuexpire");
394
395 if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) {
396 if (rt->rt_rmx.rmx_expire <= time_second) {
397 rt->rt_flags |= RTF_PROBEMTU;
398 } else {
399 ap->nextstop = lmin(ap->nextstop,
400 rt->rt_rmx.rmx_expire);
401 }
402 }
403
404 return 0;
405 }
406
407 #define MTUTIMO_DEFAULT (60*1)
408
409 static void
410 in6_mtutimo(void *rock)
411 {
412 struct radix_node_head *rnh = rock;
413 struct mtuex_arg arg;
414 struct timeval atv;
415
416 arg.rnh = rnh;
417 arg.nextstop = time_second + MTUTIMO_DEFAULT;
418 RADIX_NODE_HEAD_LOCK(rnh);
419 rnh->rnh_walktree(rnh, in6_mtuexpire, &arg);
420 RADIX_NODE_HEAD_UNLOCK(rnh);
421
422 atv.tv_usec = 0;
423 atv.tv_sec = arg.nextstop - time_second;
424 if (atv.tv_sec < 0) {
425 printf("invalid mtu expiration time on routing table\n");
426 arg.nextstop = 30; /* last resort */
427 }
428 callout_reset(&rtq_mtutimer, tvtohz(&atv), in6_mtutimo, rock);
429 }
430
431 #if 0
432 void
433 in6_rtqdrain()
434 {
435 struct radix_node_head *rnh = rt_tables[AF_INET6];
436 struct rtqk_arg arg;
437
438 arg.found = arg.killed = 0;
439 arg.rnh = rnh;
440 arg.nextstop = 0;
441 arg.draining = 1;
442 arg.updating = 0;
443 RADIX_NODE_HEAD_LOCK(rnh);
444 rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
445 RADIX_NODE_HEAD_UNLOCK(rnh);
446 }
447 #endif
448
449 /*
450 * Initialize our routing tree.
451 */
452 int
453 in6_inithead(void **head, int off)
454 {
455 struct radix_node_head *rnh;
456
457 if (!rn_inithead(head, off))
458 return 0;
459
460 if (head != (void **)&rt_tables[AF_INET6]) /* BOGUS! */
461 return 1; /* only do this for the real routing table */
462
463 rnh = *head;
464 rnh->rnh_addaddr = in6_addroute;
465 rnh->rnh_matchaddr = in6_matroute;
466 rnh->rnh_close = in6_clsroute;
467 callout_init(&rtq_timer, CALLOUT_MPSAFE);
468 in6_rtqtimo(rnh); /* kick off timeout first time */
469 callout_init(&rtq_mtutimer, CALLOUT_MPSAFE);
470 in6_mtutimo(rnh); /* kick off timeout first time */
471 return 1;
472 }
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