2 * Copyright 1994, 1995 Massachusetts Institute of Technology
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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 1.4 2004/01/07 11:04:23 dillon Exp $
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
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.
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>
52 #include <sys/syslog.h>
55 #include <net/route.h>
56 #include <netinet/in.h>
57 #include <netinet/in_var.h>
58 #include <netinet/ip_var.h>
60 extern int in_inithead (void **head, int off);
62 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */
65 * Do what we need to do when inserting a route.
67 static struct radix_node *
68 in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
69 struct radix_node *treenodes)
71 struct rtentry *rt = (struct rtentry *)treenodes;
72 struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
73 struct radix_node *ret;
76 * For IP, all unicast non-host routes are automatically cloning.
78 if(IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
79 rt->rt_flags |= RTF_MULTICAST;
81 if(!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) {
82 rt->rt_flags |= RTF_PRCLONING;
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).
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().
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
101 if (rt->rt_flags & RTF_HOST) {
102 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
103 rt->rt_flags |= RTF_BROADCAST;
105 if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr
106 == sin->sin_addr.s_addr)
107 rt->rt_flags |= RTF_LOCAL;
111 if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU)
113 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
115 ret = rn_addroute(v_arg, n_arg, head, treenodes);
116 if (ret == NULL && rt->rt_flags & RTF_HOST) {
119 * We are trying to add a host route, but can't.
120 * Find out if it is because of an
121 * ARP entry and delete it if so.
123 rt2 = rtalloc1((struct sockaddr *)sin, 0,
124 RTF_CLONING | RTF_PRCLONING);
126 if (rt2->rt_flags & RTF_LLINFO &&
127 rt2->rt_flags & RTF_HOST &&
129 rt2->rt_gateway->sa_family == AF_LINK) {
130 rtrequest(RTM_DELETE,
131 (struct sockaddr *)rt_key(rt2),
133 rt_mask(rt2), rt2->rt_flags, 0);
134 ret = rn_addroute(v_arg, n_arg, head,
142 * If the new route created successfully, and we are forwarding,
143 * and there is a cached route, free it. Otherwise, we may end
144 * up using the wrong route.
146 if (ret != NULL && ipforwarding && ipforward_rt.ro_rt) {
147 RTFREE(ipforward_rt.ro_rt);
148 ipforward_rt.ro_rt = 0;
155 * This code is the inverse of in_clsroute: on first reference, if we
156 * were managing the route, stop doing so and set the expiration timer
159 static struct radix_node *
160 in_matroute(void *v_arg, struct radix_node_head *head)
162 struct radix_node *rn = rn_match(v_arg, head);
163 struct rtentry *rt = (struct rtentry *)rn;
165 if(rt && rt->rt_refcnt == 0) { /* this is first reference */
166 if(rt->rt_flags & RTPRF_OURS) {
167 rt->rt_flags &= ~RTPRF_OURS;
168 rt->rt_rmx.rmx_expire = 0;
174 static int rtq_reallyold = 60*60;
175 /* one hour is ``really old'' */
176 SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
178 "Default expiration time on dynamically learned routes");
180 static int rtq_minreallyold = 10;
181 /* never automatically crank down to less */
182 SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
183 &rtq_minreallyold , 0,
184 "Minimum time to attempt to hold onto dynamically learned routes");
186 static int rtq_toomany = 128;
187 /* 128 cached routes is ``too many'' */
188 SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
189 &rtq_toomany , 0, "Upper limit on dynamically learned routes");
192 * On last reference drop, mark the route as belong to us so that it can be
196 in_clsroute(struct radix_node *rn, struct radix_node_head *head)
198 struct rtentry *rt = (struct rtentry *)rn;
200 if(!(rt->rt_flags & RTF_UP))
201 return; /* prophylactic measures */
203 if((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
206 if((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS))
211 * As requested by David Greenman:
212 * If rtq_reallyold is 0, just delete the route without
213 * waiting for a timeout cycle to kill it.
215 if(rtq_reallyold != 0) {
216 rt->rt_flags |= RTPRF_OURS;
217 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
219 rtrequest(RTM_DELETE,
220 (struct sockaddr *)rt_key(rt),
221 rt->rt_gateway, rt_mask(rt),
227 struct radix_node_head *rnh;
236 * Get rid of old routes. When draining, this deletes everything, even when
237 * the timeout is not expired yet. When updating, this makes sure that
238 * nothing has a timeout longer than the current value of rtq_reallyold.
241 in_rtqkill(struct radix_node *rn, void *rock)
243 struct rtqk_arg *ap = rock;
244 struct rtentry *rt = (struct rtentry *)rn;
247 if(rt->rt_flags & RTPRF_OURS) {
250 if(ap->draining || rt->rt_rmx.rmx_expire <= time_second) {
251 if(rt->rt_refcnt > 0)
252 panic("rtqkill route really not free");
254 err = rtrequest(RTM_DELETE,
255 (struct sockaddr *)rt_key(rt),
256 rt->rt_gateway, rt_mask(rt),
259 log(LOG_WARNING, "in_rtqkill: error %d\n", err);
265 && (rt->rt_rmx.rmx_expire - time_second
267 rt->rt_rmx.rmx_expire = time_second
270 ap->nextstop = lmin(ap->nextstop,
271 rt->rt_rmx.rmx_expire);
278 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
279 static int rtq_timeout = RTQ_TIMEOUT;
282 in_rtqtimo(void *rock)
284 struct radix_node_head *rnh = rock;
287 static time_t last_adjusted_timeout = 0;
290 arg.found = arg.killed = 0;
292 arg.nextstop = time_second + rtq_timeout;
293 arg.draining = arg.updating = 0;
295 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
299 * Attempt to be somewhat dynamic about this:
300 * If there are ``too many'' routes sitting around taking up space,
301 * then crank down the timeout, and see if we can't make some more
302 * go away. However, we make sure that we will never adjust more
303 * than once in rtq_timeout seconds, to keep from cranking down too
306 if((arg.found - arg.killed > rtq_toomany)
307 && (time_second - last_adjusted_timeout >= rtq_timeout)
308 && rtq_reallyold > rtq_minreallyold) {
309 rtq_reallyold = 2*rtq_reallyold / 3;
310 if(rtq_reallyold < rtq_minreallyold) {
311 rtq_reallyold = rtq_minreallyold;
314 last_adjusted_timeout = time_second;
316 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
319 arg.found = arg.killed = 0;
322 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
327 atv.tv_sec = arg.nextstop - time_second;
328 timeout(in_rtqtimo, rock, tvtohz_high(&atv));
334 struct radix_node_head *rnh = rt_tables[AF_INET];
337 arg.found = arg.killed = 0;
343 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
348 * Initialize our routing tree.
351 in_inithead(void **head, int off)
353 struct radix_node_head *rnh;
355 if(!rn_inithead(head, off))
358 if(head != (void **)&rt_tables[AF_INET]) /* BOGUS! */
359 return 1; /* only do this for the real routing table */
362 rnh->rnh_addaddr = in_addroute;
363 rnh->rnh_matchaddr = in_matroute;
364 rnh->rnh_close = in_clsroute;
365 in_rtqtimo(rnh); /* kick off timeout first time */
371 * This zaps old routes when the interface goes down or interface
372 * address is deleted. In the latter case, it deletes static routes
373 * that point to this address. If we don't do this, we may end up
374 * using the old address in the future. The ones we always want to
375 * get rid of are things like ARP entries, since the user might down
376 * the interface, walk over to a completely different network, and
379 struct in_ifadown_arg {
380 struct radix_node_head *rnh;
386 in_ifadownkill(struct radix_node *rn, void *xap)
388 struct in_ifadown_arg *ap = xap;
389 struct rtentry *rt = (struct rtentry *)rn;
392 if (rt->rt_ifa == ap->ifa &&
393 (ap->del || !(rt->rt_flags & RTF_STATIC))) {
395 * We need to disable the automatic prune that happens
396 * in this case in rtrequest() because it will blow
397 * away the pointers that rn_walktree() needs in order
398 * continue our descent. We will end up deleting all
399 * the routes that rtrequest() would have in any case,
400 * so that behavior is not needed there.
402 rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
403 err = rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt),
404 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
406 log(LOG_WARNING, "in_ifadownkill: error %d\n", err);
413 in_ifadown(struct ifaddr *ifa, int delete)
415 struct in_ifadown_arg arg;
416 struct radix_node_head *rnh;
418 if (ifa->ifa_addr->sa_family != AF_INET)
421 arg.rnh = rnh = rt_tables[AF_INET];
424 rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
425 ifa->ifa_flags &= ~IFA_ROUTE;