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 1.6 2004/09/16 23:06:42 joerg Exp $ */
3 /* $KAME: in6_rmx.c,v 1.11 2001/07/26 06:53:16 jinmei Exp $ */
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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
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.
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>
85 #include <sys/syslog.h>
88 #include <net/route.h>
89 #include <netinet/in.h>
90 #include <netinet/ip_var.h>
91 #include <netinet/in_var.h>
93 #include <netinet/ip6.h>
94 #include <netinet6/ip6_var.h>
96 #include <netinet/icmp6.h>
98 #include <netinet/tcp.h>
99 #include <netinet/tcp_seq.h>
100 #include <netinet/tcp_timer.h>
101 #include <netinet/tcp_var.h>
103 static struct callout in6_rtqtimo_ch;
104 static struct callout in6_mtutimo_ch;
106 extern int in6_inithead (void **head, int off);
108 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */
111 * Do what we need to do when inserting a route.
113 static struct radix_node *
114 in6_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
115 struct radix_node *treenodes)
117 struct rtentry *rt = (struct rtentry *)treenodes;
118 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)rt_key(rt);
119 struct radix_node *ret;
122 * For IPv6, all unicast non-host routes are automatically cloning.
124 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
125 rt->rt_flags |= RTF_MULTICAST;
127 if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) {
128 rt->rt_flags |= RTF_PRCLONING;
132 * A little bit of help for both IPv6 output and input:
133 * For local addresses, we make sure that RTF_LOCAL is set,
134 * with the thought that this might one day be used to speed up
137 * We also mark routes to multicast addresses as such, because
138 * it's easy to do and might be useful (but this is much more
139 * dubious since it's so easy to inspect the address). (This
143 * should elaborate the code.
145 if (rt->rt_flags & RTF_HOST) {
146 if (IN6_ARE_ADDR_EQUAL(&satosin6(rt->rt_ifa->ifa_addr)
149 rt->rt_flags |= RTF_LOCAL;
153 if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU)
155 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
157 ret = rn_addroute(v_arg, n_arg, head, treenodes);
158 if (ret == NULL && rt->rt_flags & RTF_HOST) {
161 * We are trying to add a host route, but can't.
162 * Find out if it is because of an
163 * ARP entry and delete it if so.
165 rt2 = rtalloc1((struct sockaddr *)sin6, 0,
166 RTF_CLONING | RTF_PRCLONING);
168 if (rt2->rt_flags & RTF_LLINFO &&
169 rt2->rt_flags & RTF_HOST &&
171 rt2->rt_gateway->sa_family == AF_LINK) {
172 rtrequest(RTM_DELETE,
173 (struct sockaddr *)rt_key(rt2),
175 rt_mask(rt2), rt2->rt_flags, 0);
176 ret = rn_addroute(v_arg, n_arg, head,
181 } else if (ret == NULL && rt->rt_flags & RTF_CLONING) {
184 * We are trying to add a net route, but can't.
185 * The following case should be allowed, so we'll make a
186 * special check for this:
187 * Two IPv6 addresses with the same prefix is assigned
188 * to a single interrface.
189 * # ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1)
190 * # ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2)
191 * In this case, (*1) and (*2) want to add the same
192 * net route entry, 3ffe:0501:: -> if0.
193 * This case should not raise an error.
195 rt2 = rtalloc1((struct sockaddr *)sin6, 0,
196 RTF_CLONING | RTF_PRCLONING);
198 if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY))
201 && rt2->rt_gateway->sa_family == AF_LINK
202 && rt2->rt_ifp == rt->rt_ifp) {
212 * This code is the inverse of in6_clsroute: on first reference, if we
213 * were managing the route, stop doing so and set the expiration timer
216 static struct radix_node *
217 in6_matroute(void *v_arg, struct radix_node_head *head)
219 struct radix_node *rn = rn_match(v_arg, head);
220 struct rtentry *rt = (struct rtentry *)rn;
222 if (rt && rt->rt_refcnt == 0) { /* this is first reference */
223 if (rt->rt_flags & RTPRF_OURS) {
224 rt->rt_flags &= ~RTPRF_OURS;
225 rt->rt_rmx.rmx_expire = 0;
231 SYSCTL_DECL(_net_inet6_ip6);
233 static int rtq_reallyold = 60*60;
234 /* one hour is ``really old'' */
235 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTEXPIRE, rtexpire,
236 CTLFLAG_RW, &rtq_reallyold , 0, "");
238 static int rtq_minreallyold = 10;
239 /* never automatically crank down to less */
240 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMINEXPIRE, rtminexpire,
241 CTLFLAG_RW, &rtq_minreallyold , 0, "");
243 static int rtq_toomany = 128;
244 /* 128 cached routes is ``too many'' */
245 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMAXCACHE, rtmaxcache,
246 CTLFLAG_RW, &rtq_toomany , 0, "");
250 * On last reference drop, mark the route as belong to us so that it can be
254 in6_clsroute(struct radix_node *rn, struct radix_node_head *head)
256 struct rtentry *rt = (struct rtentry *)rn;
258 if (!(rt->rt_flags & RTF_UP))
259 return; /* prophylactic measures */
261 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
264 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS))
269 * As requested by David Greenman:
270 * If rtq_reallyold is 0, just delete the route without
271 * waiting for a timeout cycle to kill it.
273 if (rtq_reallyold != 0) {
274 rt->rt_flags |= RTPRF_OURS;
275 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
277 rtrequest(RTM_DELETE,
278 (struct sockaddr *)rt_key(rt),
279 rt->rt_gateway, rt_mask(rt),
285 struct radix_node_head *rnh;
295 * Get rid of old routes. When draining, this deletes everything, even when
296 * the timeout is not expired yet. When updating, this makes sure that
297 * nothing has a timeout longer than the current value of rtq_reallyold.
300 in6_rtqkill(struct radix_node *rn, void *rock)
302 struct rtqk_arg *ap = rock;
303 struct rtentry *rt = (struct rtentry *)rn;
306 if (rt->rt_flags & RTPRF_OURS) {
309 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) {
310 if (rt->rt_refcnt > 0)
311 panic("rtqkill route really not free");
313 err = rtrequest(RTM_DELETE,
314 (struct sockaddr *)rt_key(rt),
315 rt->rt_gateway, rt_mask(rt),
318 log(LOG_WARNING, "in6_rtqkill: error %d", err);
324 && (rt->rt_rmx.rmx_expire - time_second
326 rt->rt_rmx.rmx_expire = time_second
329 ap->nextstop = lmin(ap->nextstop,
330 rt->rt_rmx.rmx_expire);
337 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
338 static int rtq_timeout = RTQ_TIMEOUT;
341 in6_rtqtimo(void *rock)
343 struct radix_node_head *rnh = rock;
346 static time_t last_adjusted_timeout = 0;
349 arg.found = arg.killed = 0;
351 arg.nextstop = time_second + rtq_timeout;
352 arg.draining = arg.updating = 0;
354 rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
358 * Attempt to be somewhat dynamic about this:
359 * If there are ``too many'' routes sitting around taking up space,
360 * then crank down the timeout, and see if we can't make some more
361 * go away. However, we make sure that we will never adjust more
362 * than once in rtq_timeout seconds, to keep from cranking down too
365 if ((arg.found - arg.killed > rtq_toomany)
366 && (time_second - last_adjusted_timeout >= rtq_timeout)
367 && rtq_reallyold > rtq_minreallyold) {
368 rtq_reallyold = 2*rtq_reallyold / 3;
369 if (rtq_reallyold < rtq_minreallyold) {
370 rtq_reallyold = rtq_minreallyold;
373 last_adjusted_timeout = time_second;
375 log(LOG_DEBUG, "in6_rtqtimo: adjusted rtq_reallyold to %d",
378 arg.found = arg.killed = 0;
381 rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
386 atv.tv_sec = arg.nextstop;
387 callout_reset(&in6_rtqtimo_ch, tvtohz_high(&atv), in6_rtqtimo, rock);
394 struct radix_node_head *rnh;
399 in6_mtuexpire(struct radix_node *rn, void *rock)
401 struct rtentry *rt = (struct rtentry *)rn;
402 struct mtuex_arg *ap = rock;
406 panic("rt == NULL in in6_mtuexpire");
408 if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) {
409 if (rt->rt_rmx.rmx_expire <= time_second) {
410 rt->rt_flags |= RTF_PROBEMTU;
412 ap->nextstop = lmin(ap->nextstop,
413 rt->rt_rmx.rmx_expire);
420 #define MTUTIMO_DEFAULT (60*1)
423 in6_mtutimo(void *rock)
425 struct radix_node_head *rnh = rock;
426 struct mtuex_arg arg;
431 arg.nextstop = time_second + MTUTIMO_DEFAULT;
433 rnh->rnh_walktree(rnh, in6_mtuexpire, &arg);
437 atv.tv_sec = arg.nextstop;
438 if (atv.tv_sec < time_second) {
439 printf("invalid mtu expiration time on routing table\n");
440 arg.nextstop = time_second + 30; /* last resort */
442 callout_reset(&in6_mtutimo_ch, tvtohz_high(&atv), in6_mtutimo, rock);
449 struct radix_node_head *rnh = rt_tables[AF_INET6];
452 arg.found = arg.killed = 0;
458 rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
464 * Initialize our routing tree.
467 in6_inithead(void **head, int off)
469 struct radix_node_head *rnh;
471 if (!rn_inithead(head, off))
474 if (head != (void **)&rt_tables[AF_INET6]) /* BOGUS! */
475 return 1; /* only do this for the real routing table */
478 rnh->rnh_addaddr = in6_addroute;
479 rnh->rnh_matchaddr = in6_matroute;
480 rnh->rnh_close = in6_clsroute;
481 callout_init(&in6_mtutimo_ch);
482 callout_init(&in6_rtqtimo_ch);
483 in6_rtqtimo(rnh); /* kick off timeout first time */
484 in6_mtutimo(rnh); /* kick off timeout first time */