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 <net/netmsg2.h>
65 #include <net/netisr2.h>
66 #include <netinet/in.h>
67 #include <netinet/in_var.h>
68 #include <netinet/ip_var.h>
69 #include <netinet/ip_flow.h>
71 #define RTPRF_EXPIRING RTF_PROTO3 /* set on routes we manage */
73 struct in_rtqtimo_ctx {
74 struct callout timo_ch;
75 struct netmsg_base timo_nmsg;
76 struct radix_node_head *timo_rnh;
79 static void in_rtqtimo(void *);
81 static struct in_rtqtimo_ctx in_rtqtimo_context[MAXCPU];
84 * Do what we need to do when inserting a route.
86 static struct radix_node *
87 in_addroute(char *key, char *mask, struct radix_node_head *head,
88 struct radix_node *treenodes)
90 struct rtentry *rt = (struct rtentry *)treenodes;
91 struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
92 struct radix_node *ret;
93 struct in_ifaddr_container *iac;
97 * For IP, mark routes to multicast addresses as such, because
98 * it's easy to do and might be useful (but this is much more
99 * dubious since it's so easy to inspect the address).
101 * For IP, all unicast non-host routes are automatically cloning.
103 if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
104 rt->rt_flags |= RTF_MULTICAST;
106 if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST)))
107 rt->rt_flags |= RTF_PRCLONING;
110 * For host routes, we make sure that RTF_BROADCAST
111 * is set for anything that looks like a broadcast address.
112 * This way, we can avoid an expensive call to in_broadcast()
113 * in ip_output() most of the time (because the route passed
114 * to ip_output() is almost always a host route).
116 * For local routes we set RTF_LOCAL allowing various shortcuts.
118 * A cloned network route will point to one of several possible
119 * addresses if an interface has aliases and must be repointed
120 * back to the correct address or arp_rtrequest() will not properly
121 * detect the local ip.
123 if (rt->rt_flags & RTF_HOST) {
124 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
125 rt->rt_flags |= RTF_BROADCAST;
126 } else if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr ==
127 sin->sin_addr.s_addr) {
128 rt->rt_flags |= RTF_LOCAL;
130 LIST_FOREACH(iac, INADDR_HASH(sin->sin_addr.s_addr),
133 if (sin->sin_addr.s_addr ==
134 ia->ia_addr.sin_addr.s_addr) {
135 rt->rt_flags |= RTF_LOCAL;
138 rt->rt_ifa = &ia->ia_ifa;
139 rt->rt_ifp = rt->rt_ifa->ifa_ifp;
146 if (rt->rt_rmx.rmx_mtu != 0 && !(rt->rt_rmx.rmx_locks & RTV_MTU) &&
148 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
150 ret = rn_addroute(key, mask, head, treenodes);
151 if (ret == NULL && (rt->rt_flags & RTF_HOST)) {
152 struct rtentry *oldrt;
155 * We are trying to add a host route, but can't.
156 * Find out if it is because of an ARP entry and
159 oldrt = rtpurelookup((struct sockaddr *)sin);
162 if ((oldrt->rt_flags & RTF_LLINFO) &&
163 (oldrt->rt_flags & RTF_HOST) &&
165 oldrt->rt_gateway->sa_family == AF_LINK) {
166 rtrequest(RTM_DELETE, rt_key(oldrt),
167 oldrt->rt_gateway, rt_mask(oldrt),
168 oldrt->rt_flags, NULL);
169 ret = rn_addroute(key, mask, head, treenodes);
175 * If the new route has been created successfully, and it is
176 * not a multicast/broadcast or cloned route, then we will
177 * have to flush the ipflow. Otherwise, we may end up using
182 (RTF_MULTICAST | RTF_BROADCAST | RTF_WASCLONED)) == 0) {
183 ipflow_flush_oncpu();
189 * This code is the inverse of in_closeroute: on first reference, if we
190 * were managing the route, stop doing so and set the expiration timer
193 static struct radix_node *
194 in_matchroute(char *key, struct radix_node_head *head)
196 struct radix_node *rn = rn_match(key, head);
197 struct rtentry *rt = (struct rtentry *)rn;
199 if (rt != NULL && rt->rt_refcnt == 0) { /* this is first reference */
200 if (rt->rt_flags & RTPRF_EXPIRING) {
201 rt->rt_flags &= ~RTPRF_EXPIRING;
202 rt->rt_rmx.rmx_expire = 0;
208 static int rtq_reallyold = 60*60; /* one hour is ``really old'' */
209 SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
211 "Default expiration time on cloned routes");
213 static int rtq_minreallyold = 10; /* never automatically crank down to less */
214 SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
215 &rtq_minreallyold , 0,
216 "Minimum time to attempt to hold onto cloned routes");
218 static int rtq_toomany = 128; /* 128 cached routes is ``too many'' */
219 SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
220 &rtq_toomany , 0, "Upper limit on cloned routes");
223 * On last reference drop, mark the route as belong to us so that it can be
227 in_closeroute(struct radix_node *rn, struct radix_node_head *head)
229 struct rtentry *rt = (struct rtentry *)rn;
231 if (!(rt->rt_flags & RTF_UP))
232 return; /* prophylactic measures */
234 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
237 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_EXPIRING)) != RTF_WASCLONED)
241 * As requested by David Greenman:
242 * If rtq_reallyold is 0, just delete the route without
243 * waiting for a timeout cycle to kill it.
245 if (rtq_reallyold != 0) {
246 rt->rt_flags |= RTPRF_EXPIRING;
247 rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
250 * Remove route from the radix tree, but defer deallocation
251 * until we return to rtfree().
253 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt),
259 struct radix_node_head *rnh;
268 * Get rid of old routes. When draining, this deletes everything, even when
269 * the timeout is not expired yet. When updating, this makes sure that
270 * nothing has a timeout longer than the current value of rtq_reallyold.
273 in_rtqkill(struct radix_node *rn, void *rock)
275 struct rtqk_arg *ap = rock;
276 struct rtentry *rt = (struct rtentry *)rn;
279 if (rt->rt_flags & RTPRF_EXPIRING) {
281 if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) {
282 if (rt->rt_refcnt > 0)
283 panic("rtqkill route really not free");
285 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
286 rt_mask(rt), rt->rt_flags, NULL);
288 log(LOG_WARNING, "in_rtqkill: error %d\n", err);
293 (rt->rt_rmx.rmx_expire - time_second >
295 rt->rt_rmx.rmx_expire = time_second +
298 ap->nextstop = lmin(ap->nextstop,
299 rt->rt_rmx.rmx_expire);
306 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
307 static int rtq_timeout = RTQ_TIMEOUT;
311 * 'last_adjusted_timeout' and 'rtq_reallyold' are _not_ read-only, and
312 * could be changed by all CPUs. However, they are changed at so low
313 * frequency that we could ignore the cache trashing issue and take them
317 in_rtqtimo_dispatch(netmsg_t nmsg)
321 static time_t last_adjusted_timeout = 0;
322 struct in_rtqtimo_ctx *ctx = &in_rtqtimo_context[mycpuid];
323 struct radix_node_head *rnh = ctx->timo_rnh;
327 lwkt_replymsg(&nmsg->lmsg, 0);
330 arg.found = arg.killed = 0;
332 arg.nextstop = time_second + rtq_timeout;
333 arg.draining = arg.updating = 0;
334 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
337 * Attempt to be somewhat dynamic about this:
338 * If there are ``too many'' routes sitting around taking up space,
339 * then crank down the timeout, and see if we can't make some more
340 * go away. However, we make sure that we will never adjust more
341 * than once in rtq_timeout seconds, to keep from cranking down too
344 if ((arg.found - arg.killed > rtq_toomany) &&
345 (time_second - last_adjusted_timeout >= rtq_timeout) &&
346 rtq_reallyold > rtq_minreallyold) {
347 rtq_reallyold = 2*rtq_reallyold / 3;
348 if (rtq_reallyold < rtq_minreallyold) {
349 rtq_reallyold = rtq_minreallyold;
352 last_adjusted_timeout = time_second;
354 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
357 arg.found = arg.killed = 0;
359 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
363 atv.tv_sec = arg.nextstop - time_second;
364 callout_reset(&ctx->timo_ch, tvtohz_high(&atv), in_rtqtimo, NULL);
368 in_rtqtimo(void *arg __unused)
371 struct lwkt_msg *lmsg = &in_rtqtimo_context[cpuid].timo_nmsg.lmsg;
374 if (lmsg->ms_flags & MSGF_DONE)
375 lwkt_sendmsg(netisr_cpuport(cpuid), lmsg);
382 struct radix_node_head *rnh = rt_tables[mycpuid][AF_INET];
385 arg.found = arg.killed = 0;
391 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
396 * Initialize our routing tree.
399 in_inithead(void **head, int off)
401 struct radix_node_head *rnh;
402 struct in_rtqtimo_ctx *ctx;
405 if (!rn_inithead(head, rn_cpumaskhead(cpuid), off))
408 if (head != (void **)&rt_tables[cpuid][AF_INET]) /* BOGUS! */
409 return 1; /* only do this for the real routing table */
412 rnh->rnh_addaddr = in_addroute;
413 rnh->rnh_matchaddr = in_matchroute;
414 rnh->rnh_close = in_closeroute;
416 ctx = &in_rtqtimo_context[cpuid];
418 callout_init_mp(&ctx->timo_ch);
419 netmsg_init(&ctx->timo_nmsg, NULL, &netisr_adone_rport, 0,
420 in_rtqtimo_dispatch);
422 in_rtqtimo(NULL); /* kick off timeout first time */
427 * This zaps old routes when the interface goes down or interface
428 * address is deleted. In the latter case, it deletes static routes
429 * that point to this address. If we don't do this, we may end up
430 * using the old address in the future. The ones we always want to
431 * get rid of are things like ARP entries, since the user might down
432 * the interface, walk over to a completely different network, and
435 * in_ifadown() is typically called when an interface is being brought
436 * down. We must iterate through all per-cpu route tables and clean
439 struct in_ifadown_arg {
440 struct radix_node_head *rnh;
446 in_ifadownkill(struct radix_node *rn, void *xap)
448 struct in_ifadown_arg *ap = xap;
449 struct rtentry *rt = (struct rtentry *)rn;
452 if (rt->rt_ifa == ap->ifa &&
453 (ap->del || !(rt->rt_flags & RTF_STATIC))) {
455 * We need to disable the automatic prune that happens
456 * in this case in rtrequest() because it will blow
457 * away the pointers that rn_walktree() needs in order
458 * continue our descent. We will end up deleting all
459 * the routes that rtrequest() would have in any case,
460 * so that behavior is not needed there.
462 rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
463 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
464 rt_mask(rt), rt->rt_flags, NULL);
466 log(LOG_WARNING, "in_ifadownkill: error %d\n", err);
471 struct netmsg_ifadown {
472 struct netmsg_base base;
478 in_ifadown_dispatch(netmsg_t msg)
480 struct netmsg_ifadown *rmsg = (void *)msg;
481 struct radix_node_head *rnh;
482 struct ifaddr *ifa = rmsg->ifa;
483 struct in_ifadown_arg arg;
488 arg.rnh = rnh = rt_tables[cpu][AF_INET];
491 rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
492 ifa->ifa_flags &= ~IFA_ROUTE;
496 lwkt_forwardmsg(netisr_cpuport(nextcpu), &rmsg->base.lmsg);
498 lwkt_replymsg(&rmsg->base.lmsg, 0);
502 in_ifadown_force(struct ifaddr *ifa, int delete)
504 struct netmsg_ifadown msg;
506 if (ifa->ifa_addr->sa_family != AF_INET)
510 * XXX individual requests are not independantly chained,
511 * which means that the per-cpu route tables will not be
512 * consistent in the middle of the operation. If routes
513 * related to the interface are manipulated while we are
514 * doing this the inconsistancy could trigger a panic.
516 netmsg_init(&msg.base, NULL, &curthread->td_msgport, MSGF_PRIORITY,
517 in_ifadown_dispatch);
520 rt_domsg_global(&msg.base);
526 in_ifadown(struct ifaddr *ifa, int delete)
529 if (ifa->ifa_ifp->if_type == IFT_CARP)
532 return in_ifadown_force(ifa, delete);