2 * Copyright 1994, 1995 Massachusetts Institute of Technology
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5 * its documentation for any purpose and without fee is hereby
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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 1.14 2006/04/11 06:59:34 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.
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
51 #include <sys/sysctl.h>
52 #include <sys/socket.h>
54 #include <sys/syslog.h>
55 #include <sys/globaldata.h>
56 #include <sys/thread2.h>
59 #include <net/route.h>
60 #include <net/if_var.h>
62 #include <net/if_types.h>
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
66 #include <netinet/ip_var.h>
67 #include <netinet/ip_flow.h>
69 #define RTPRF_EXPIRING RTF_PROTO3 /* set on routes we manage */
71 static struct callout in_rtqtimo_ch[MAXCPU];
74 * Do what we need to do when inserting a route.
76 static struct radix_node *
77 in_addroute(char *key, char *mask, struct radix_node_head *head,
78 struct radix_node *treenodes)
80 struct rtentry *rt = (struct rtentry *)treenodes;
81 struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
82 struct radix_node *ret;
83 struct in_ifaddr_container *iac;
87 * For IP, mark routes to multicast addresses as such, because
88 * it's easy to do and might be useful (but this is much more
89 * dubious since it's so easy to inspect the address).
91 * For IP, all unicast non-host routes are automatically cloning.
93 if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
94 rt->rt_flags |= RTF_MULTICAST;
96 if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST)))
97 rt->rt_flags |= RTF_PRCLONING;
100 * For host routes, we make sure that RTF_BROADCAST
101 * is set for anything that looks like a broadcast address.
102 * This way, we can avoid an expensive call to in_broadcast()
103 * in ip_output() most of the time (because the route passed
104 * to ip_output() is almost always a host route).
106 * For local routes we set RTF_LOCAL allowing various shortcuts.
108 * A cloned network route will point to one of several possible
109 * addresses if an interface has aliases and must be repointed
110 * back to the correct address or arp_rtrequest() will not properly
111 * detect the local ip.
113 if (rt->rt_flags & RTF_HOST) {
114 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
115 rt->rt_flags |= RTF_BROADCAST;
116 } else if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr ==
117 sin->sin_addr.s_addr) {
118 rt->rt_flags |= RTF_LOCAL;
120 LIST_FOREACH(iac, INADDR_HASH(sin->sin_addr.s_addr),
123 if (sin->sin_addr.s_addr ==
124 ia->ia_addr.sin_addr.s_addr) {
125 rt->rt_flags |= RTF_LOCAL;
128 rt->rt_ifa = &ia->ia_ifa;
129 rt->rt_ifp = rt->rt_ifa->ifa_ifp;
136 if (rt->rt_rmx.rmx_mtu != 0 && !(rt->rt_rmx.rmx_locks & RTV_MTU) &&
138 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
140 ret = rn_addroute(key, mask, head, treenodes);
141 if (ret == NULL && (rt->rt_flags & RTF_HOST)) {
142 struct rtentry *oldrt;
145 * We are trying to add a host route, but can't.
146 * Find out if it is because of an ARP entry and
149 oldrt = rtpurelookup((struct sockaddr *)sin);
152 if ((oldrt->rt_flags & RTF_LLINFO) &&
153 (oldrt->rt_flags & RTF_HOST) &&
155 oldrt->rt_gateway->sa_family == AF_LINK) {
156 rtrequest(RTM_DELETE, rt_key(oldrt),
157 oldrt->rt_gateway, rt_mask(oldrt),
158 oldrt->rt_flags, NULL);
159 ret = rn_addroute(key, mask, head, treenodes);
165 * If the new route has been created successfully, and it is
166 * not a multicast/broadcast or cloned route, then we will
167 * have to flush the ipflow. Otherwise, we may end up using
172 (RTF_MULTICAST | RTF_BROADCAST | RTF_WASCLONED)) == 0) {
173 ipflow_flush_oncpu();
179 * This code is the inverse of in_closeroute: on first reference, if we
180 * were managing the route, stop doing so and set the expiration timer
183 static struct radix_node *
184 in_matchroute(char *key, struct radix_node_head *head)
186 struct radix_node *rn = rn_match(key, head);
187 struct rtentry *rt = (struct rtentry *)rn;
189 if (rt != NULL && rt->rt_refcnt == 0) { /* this is first reference */
190 if (rt->rt_flags & RTPRF_EXPIRING) {
191 rt->rt_flags &= ~RTPRF_EXPIRING;
192 rt->rt_rmx.rmx_expire = 0;
198 static int rtq_reallyold = 60*60; /* one hour is ``really old'' */
199 SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
201 "Default expiration time on cloned routes");
203 static int rtq_minreallyold = 10; /* never automatically crank down to less */
204 SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
205 &rtq_minreallyold , 0,
206 "Minimum time to attempt to hold onto cloned routes");
208 static int rtq_toomany = 128; /* 128 cached routes is ``too many'' */
209 SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
210 &rtq_toomany , 0, "Upper limit on cloned routes");
213 * On last reference drop, mark the route as belong to us so that it can be
217 in_closeroute(struct radix_node *rn, struct radix_node_head *head)
219 struct rtentry *rt = (struct rtentry *)rn;
221 if (!(rt->rt_flags & RTF_UP))
222 return; /* prophylactic measures */
224 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
227 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_EXPIRING)) != RTF_WASCLONED)
231 * As requested by David Greenman:
232 * If rtq_reallyold is 0, just delete the route without
233 * waiting for a timeout cycle to kill it.
235 if (rtq_reallyold != 0) {
236 rt->rt_flags |= RTPRF_EXPIRING;
237 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
240 * Remove route from the radix tree, but defer deallocation
241 * until we return to rtfree().
243 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt),
249 struct radix_node_head *rnh;
258 * Get rid of old routes. When draining, this deletes everything, even when
259 * the timeout is not expired yet. When updating, this makes sure that
260 * nothing has a timeout longer than the current value of rtq_reallyold.
263 in_rtqkill(struct radix_node *rn, void *rock)
265 struct rtqk_arg *ap = rock;
266 struct rtentry *rt = (struct rtentry *)rn;
269 if (rt->rt_flags & RTPRF_EXPIRING) {
271 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) {
272 if (rt->rt_refcnt > 0)
273 panic("rtqkill route really not free");
275 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
276 rt_mask(rt), rt->rt_flags, NULL);
278 log(LOG_WARNING, "in_rtqkill: error %d\n", err);
283 (rt->rt_rmx.rmx_expire - time_second >
285 rt->rt_rmx.rmx_expire = time_second +
288 ap->nextstop = lmin(ap->nextstop,
289 rt->rt_rmx.rmx_expire);
296 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
297 static int rtq_timeout = RTQ_TIMEOUT;
300 in_rtqtimo(void *rock)
302 struct radix_node_head *rnh = rock;
305 static time_t last_adjusted_timeout = 0;
307 arg.found = arg.killed = 0;
309 arg.nextstop = time_second + rtq_timeout;
310 arg.draining = arg.updating = 0;
312 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
316 * Attempt to be somewhat dynamic about this:
317 * If there are ``too many'' routes sitting around taking up space,
318 * then crank down the timeout, and see if we can't make some more
319 * go away. However, we make sure that we will never adjust more
320 * than once in rtq_timeout seconds, to keep from cranking down too
323 if ((arg.found - arg.killed > rtq_toomany) &&
324 (time_second - last_adjusted_timeout >= rtq_timeout) &&
325 rtq_reallyold > rtq_minreallyold) {
326 rtq_reallyold = 2*rtq_reallyold / 3;
327 if (rtq_reallyold < rtq_minreallyold) {
328 rtq_reallyold = rtq_minreallyold;
331 last_adjusted_timeout = time_second;
333 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
336 arg.found = arg.killed = 0;
339 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
344 atv.tv_sec = arg.nextstop - time_second;
345 callout_reset(&in_rtqtimo_ch[mycpuid], tvtohz_high(&atv), in_rtqtimo,
352 struct radix_node_head *rnh = rt_tables[mycpuid][AF_INET];
355 arg.found = arg.killed = 0;
361 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
366 * Initialize our routing tree.
369 in_inithead(void **head, int off)
371 struct radix_node_head *rnh;
373 if (!rn_inithead(head, rn_cpumaskhead(mycpuid), off))
376 if (head != (void **)&rt_tables[mycpuid][AF_INET]) /* BOGUS! */
377 return 1; /* only do this for the real routing table */
380 rnh->rnh_addaddr = in_addroute;
381 rnh->rnh_matchaddr = in_matchroute;
382 rnh->rnh_close = in_closeroute;
383 callout_init(&in_rtqtimo_ch[mycpuid]);
384 in_rtqtimo(rnh); /* kick off timeout first time */
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
397 * in_ifadown() is typically called when an interface is being brought
398 * down. We must iterate through all per-cpu route tables and clean
401 struct in_ifadown_arg {
402 struct radix_node_head *rnh;
408 in_ifadownkill(struct radix_node *rn, void *xap)
410 struct in_ifadown_arg *ap = xap;
411 struct rtentry *rt = (struct rtentry *)rn;
414 if (rt->rt_ifa == ap->ifa &&
415 (ap->del || !(rt->rt_flags & RTF_STATIC))) {
417 * We need to disable the automatic prune that happens
418 * in this case in rtrequest() because it will blow
419 * away the pointers that rn_walktree() needs in order
420 * continue our descent. We will end up deleting all
421 * the routes that rtrequest() would have in any case,
422 * so that behavior is not needed there.
424 rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
425 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
426 rt_mask(rt), rt->rt_flags, NULL);
428 log(LOG_WARNING, "in_ifadownkill: error %d\n", err);
434 in_ifadown_force(struct ifaddr *ifa, int delete)
436 struct in_ifadown_arg arg;
437 struct radix_node_head *rnh;
441 if (ifa->ifa_addr->sa_family != AF_INET)
445 * XXX individual requests are not independantly chained,
446 * which means that the per-cpu route tables will not be
447 * consistent in the middle of the operation. If routes
448 * related to the interface are manipulated while we are
449 * doing this the inconsistancy could trigger a panic.
452 for (cpu = 0; cpu < ncpus; cpu++) {
453 lwkt_migratecpu(cpu);
455 arg.rnh = rnh = rt_tables[cpu][AF_INET];
458 rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
459 ifa->ifa_flags &= ~IFA_ROUTE;
461 lwkt_migratecpu(origcpu);
466 in_ifadown(struct ifaddr *ifa, int delete)
469 if (ifa->ifa_ifp->if_type == IFT_CARP)
472 return in_ifadown_force(ifa, delete);