2 * Copyright 1994, 1995 Massachusetts Institute of Technology
4 * Permission to use, copy, modify, and distribute this software and
5 * its documentation for any purpose and without fee is hereby
6 * granted, provided that both the above copyright notice and this
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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 */
74 struct radix_node_head *rnh;
76 struct callout timo_ch;
77 struct netmsg_base timo_nmsg;
81 struct netmsg_base drain_nmsg;
84 static void in_rtqtimo(void *);
86 static struct in_rtq_pcpu in_rtq_pcpu[MAXCPU];
89 * Do what we need to do when inserting a route.
91 static struct radix_node *
92 in_addroute(char *key, char *mask, struct radix_node_head *head,
93 struct radix_node *treenodes)
95 struct rtentry *rt = (struct rtentry *)treenodes;
96 struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
97 struct radix_node *ret;
98 struct in_ifaddr_container *iac;
102 * For IP, mark routes to multicast addresses as such, because
103 * it's easy to do and might be useful (but this is much more
104 * dubious since it's so easy to inspect the address).
106 * For IP, all unicast non-host routes are automatically cloning.
108 if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
109 rt->rt_flags |= RTF_MULTICAST;
111 if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST)))
112 rt->rt_flags |= RTF_PRCLONING;
115 * For host routes, we make sure that RTF_BROADCAST
116 * is set for anything that looks like a broadcast address.
117 * This way, we can avoid an expensive call to in_broadcast()
118 * in ip_output() most of the time (because the route passed
119 * to ip_output() is almost always a host route).
121 * For local routes we set RTF_LOCAL allowing various shortcuts.
123 * A cloned network route will point to one of several possible
124 * addresses if an interface has aliases and must be repointed
125 * back to the correct address or arp_rtrequest() will not properly
126 * detect the local ip.
128 if (rt->rt_flags & RTF_HOST) {
129 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
130 rt->rt_flags |= RTF_BROADCAST;
131 } else if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr ==
132 sin->sin_addr.s_addr) {
133 rt->rt_flags |= RTF_LOCAL;
135 LIST_FOREACH(iac, INADDR_HASH(sin->sin_addr.s_addr),
138 if (sin->sin_addr.s_addr ==
139 ia->ia_addr.sin_addr.s_addr) {
140 rt->rt_flags |= RTF_LOCAL;
143 rt->rt_ifa = &ia->ia_ifa;
144 rt->rt_ifp = rt->rt_ifa->ifa_ifp;
151 if (rt->rt_rmx.rmx_mtu == 0 && !(rt->rt_rmx.rmx_locks & RTV_MTU) &&
153 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
155 ret = rn_addroute(key, mask, head, treenodes);
156 if (ret == NULL && (rt->rt_flags & RTF_HOST)) {
157 struct rtentry *oldrt;
160 * We are trying to add a host route, but can't.
161 * Find out if it is because of an ARP entry and
164 oldrt = rtpurelookup((struct sockaddr *)sin);
167 if ((oldrt->rt_flags & RTF_LLINFO) &&
168 (oldrt->rt_flags & RTF_HOST) &&
170 oldrt->rt_gateway->sa_family == AF_LINK) {
171 rtrequest(RTM_DELETE, rt_key(oldrt),
172 oldrt->rt_gateway, rt_mask(oldrt),
173 oldrt->rt_flags, NULL);
174 ret = rn_addroute(key, mask, head, treenodes);
180 * If the new route has been created successfully, and it is
181 * not a multicast/broadcast or cloned route, then we will
182 * have to flush the ipflow. Otherwise, we may end up using
187 (RTF_MULTICAST | RTF_BROADCAST | RTF_WASCLONED)) == 0) {
188 ipflow_flush_oncpu();
194 * This code is the inverse of in_closeroute: on first reference, if we
195 * were managing the route, stop doing so and set the expiration timer
198 static struct radix_node *
199 in_matchroute(char *key, struct radix_node_head *head)
201 struct radix_node *rn = rn_match(key, head);
202 struct rtentry *rt = (struct rtentry *)rn;
204 if (rt != NULL && rt->rt_refcnt == 0) { /* this is first reference */
205 if (rt->rt_flags & RTPRF_EXPIRING) {
206 rt->rt_flags &= ~RTPRF_EXPIRING;
207 rt->rt_rmx.rmx_expire = 0;
213 static int rtq_reallyold = 60*60; /* one hour is ``really old'' */
214 SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
216 "Default expiration time on cloned routes");
218 static int rtq_minreallyold = 10; /* never automatically crank down to less */
219 SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
220 &rtq_minreallyold , 0,
221 "Minimum time to attempt to hold onto cloned routes");
223 static int rtq_toomany = 128; /* 128 cached routes is ``too many'' */
224 SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
225 &rtq_toomany , 0, "Upper limit on cloned routes");
228 * On last reference drop, mark the route as belong to us so that it can be
232 in_closeroute(struct radix_node *rn, struct radix_node_head *head)
234 struct rtentry *rt = (struct rtentry *)rn;
236 if (!(rt->rt_flags & RTF_UP))
237 return; /* prophylactic measures */
239 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
242 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_EXPIRING)) != RTF_WASCLONED)
246 * As requested by David Greenman:
247 * If rtq_reallyold is 0, just delete the route without
248 * waiting for a timeout cycle to kill it.
250 if (rtq_reallyold != 0) {
251 rt->rt_flags |= RTPRF_EXPIRING;
252 rt->rt_rmx.rmx_expire = time_uptime + rtq_reallyold;
255 * Remove route from the radix tree, but defer deallocation
256 * until we return to rtfree().
258 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt),
264 struct radix_node_head *rnh;
273 * Get rid of old routes. When draining, this deletes everything, even when
274 * the timeout is not expired yet. When updating, this makes sure that
275 * nothing has a timeout longer than the current value of rtq_reallyold.
278 in_rtqkill(struct radix_node *rn, void *rock)
280 struct rtqk_arg *ap = rock;
281 struct rtentry *rt = (struct rtentry *)rn;
284 if (rt->rt_flags & RTPRF_EXPIRING) {
286 if (ap->draining || rt->rt_rmx.rmx_expire <= time_uptime) {
287 if (rt->rt_refcnt > 0)
288 panic("rtqkill route really not free");
290 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
291 rt_mask(rt), rt->rt_flags, NULL);
293 log(LOG_WARNING, "in_rtqkill: error %d\n", err);
298 (int)(rt->rt_rmx.rmx_expire - time_uptime) >
300 rt->rt_rmx.rmx_expire = time_uptime +
303 ap->nextstop = lmin(ap->nextstop,
304 rt->rt_rmx.rmx_expire);
311 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
312 static int rtq_timeout = RTQ_TIMEOUT;
316 * 'last_adjusted_timeout' and 'rtq_reallyold' are _not_ read-only, and
317 * could be changed by all CPUs. However, they are changed at so low
318 * frequency that we could ignore the cache trashing issue and take them
322 in_rtqtimo_dispatch(netmsg_t nmsg)
326 static time_t last_adjusted_timeout = 0;
327 struct in_rtq_pcpu *pcpu = &in_rtq_pcpu[mycpuid];
328 struct radix_node_head *rnh = pcpu->rnh;
332 lwkt_replymsg(&nmsg->lmsg, 0);
335 arg.found = arg.killed = 0;
337 arg.nextstop = time_uptime + rtq_timeout;
338 arg.draining = arg.updating = 0;
339 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
342 * Attempt to be somewhat dynamic about this:
343 * If there are ``too many'' routes sitting around taking up space,
344 * then crank down the timeout, and see if we can't make some more
345 * go away. However, we make sure that we will never adjust more
346 * than once in rtq_timeout seconds, to keep from cranking down too
349 if ((arg.found - arg.killed > rtq_toomany) &&
350 (int)(time_uptime - last_adjusted_timeout) >= rtq_timeout &&
351 rtq_reallyold > rtq_minreallyold) {
352 rtq_reallyold = 2*rtq_reallyold / 3;
353 if (rtq_reallyold < rtq_minreallyold) {
354 rtq_reallyold = rtq_minreallyold;
357 last_adjusted_timeout = time_uptime;
359 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
362 arg.found = arg.killed = 0;
364 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
368 atv.tv_sec = arg.nextstop - time_uptime;
369 if ((int)atv.tv_sec < 1) { /* time shift safety */
371 arg.nextstop = time_uptime + atv.tv_sec;
373 if ((int)atv.tv_sec > rtq_timeout) { /* time shift safety */
374 atv.tv_sec = rtq_timeout;
375 arg.nextstop = time_uptime + atv.tv_sec;
377 callout_reset(&pcpu->timo_ch, tvtohz_high(&atv), in_rtqtimo, NULL);
381 in_rtqtimo(void *arg __unused)
384 struct lwkt_msg *lmsg = &in_rtq_pcpu[cpuid].timo_nmsg.lmsg;
387 if (lmsg->ms_flags & MSGF_DONE)
388 lwkt_sendmsg_oncpu(netisr_cpuport(cpuid), lmsg);
393 in_rtqdrain_oncpu(struct in_rtq_pcpu *pcpu)
395 struct radix_node_head *rnh = rt_tables[mycpuid][AF_INET];
398 arg.found = arg.killed = 0;
403 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
405 pcpu->lastdrain = time_uptime;
409 in_rtqdrain_dispatch(netmsg_t nmsg)
411 struct in_rtq_pcpu *pcpu = &in_rtq_pcpu[mycpuid];
415 lwkt_replymsg(&nmsg->lmsg, 0);
418 in_rtqdrain_oncpu(pcpu);
423 in_rtqdrain_ipi(void *arg __unused)
426 struct lwkt_msg *msg = &in_rtq_pcpu[cpu].drain_nmsg.lmsg;
429 if (msg->ms_flags & MSGF_DONE)
430 lwkt_sendmsg_oncpu(netisr_cpuport(cpu), msg);
440 CPUMASK_ASSBMASK(mask, ncpus);
441 CPUMASK_ANDMASK(mask, smp_active_mask);
443 if (IS_NETISR(curthread, mycpuid)) {
444 in_rtqdrain_oncpu(&in_rtq_pcpu[mycpuid]);
445 CPUMASK_NANDBIT(mask, mycpuid);
448 for (cpu = 0; cpu < ncpus; ++cpu) {
449 struct in_rtq_pcpu *pcpu = &in_rtq_pcpu[cpu];
451 if (!CPUMASK_TESTBIT(mask, cpu))
454 if (pcpu->draining || pcpu->lastdrain == time_uptime) {
455 /* Just drained or is draining; skip this cpu. */
456 CPUMASK_NANDBIT(mask, cpu);
462 if (CPUMASK_TESTNZERO(mask))
463 lwkt_send_ipiq_mask(mask, in_rtqdrain_ipi, NULL);
467 * Initialize our routing tree.
470 in_inithead(void **head, int off)
472 struct radix_node_head *rnh;
473 struct in_rtq_pcpu *pcpu;
476 KKASSERT(head == (void **)&rt_tables[cpuid][AF_INET]);
478 if (!rn_inithead(head, rn_cpumaskhead(cpuid), off))
482 rnh->rnh_addaddr = in_addroute;
483 rnh->rnh_matchaddr = in_matchroute;
484 rnh->rnh_close = in_closeroute;
486 pcpu = &in_rtq_pcpu[cpuid];
488 callout_init_mp(&pcpu->timo_ch);
489 netmsg_init(&pcpu->timo_nmsg, NULL, &netisr_adone_rport, MSGF_PRIORITY,
490 in_rtqtimo_dispatch);
491 netmsg_init(&pcpu->drain_nmsg, NULL, &netisr_adone_rport, MSGF_PRIORITY,
492 in_rtqdrain_dispatch);
494 in_rtqtimo(NULL); /* kick off timeout first time */
499 * This zaps old routes when the interface goes down or interface
500 * address is deleted. In the latter case, it deletes static routes
501 * that point to this address. If we don't do this, we may end up
502 * using the old address in the future. The ones we always want to
503 * get rid of are things like ARP entries, since the user might down
504 * the interface, walk over to a completely different network, and
507 * in_ifadown() is typically called when an interface is being brought
508 * down. We must iterate through all per-cpu route tables and clean
511 struct in_ifadown_arg {
512 struct radix_node_head *rnh;
518 in_ifadownkill(struct radix_node *rn, void *xap)
520 struct in_ifadown_arg *ap = xap;
521 struct rtentry *rt = (struct rtentry *)rn;
524 if (rt->rt_ifa == ap->ifa &&
525 (ap->del || !(rt->rt_flags & RTF_STATIC))) {
527 * We need to disable the automatic prune that happens
528 * in this case in rtrequest() because it will blow
529 * away the pointers that rn_walktree() needs in order
530 * continue our descent. We will end up deleting all
531 * the routes that rtrequest() would have in any case,
532 * so that behavior is not needed there.
534 rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
535 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
536 rt_mask(rt), rt->rt_flags, NULL);
538 log(LOG_WARNING, "in_ifadownkill: error %d\n", err);
543 struct netmsg_ifadown {
544 struct netmsg_base base;
550 in_ifadown_dispatch(netmsg_t msg)
552 struct netmsg_ifadown *rmsg = (void *)msg;
553 struct radix_node_head *rnh;
554 struct ifaddr *ifa = rmsg->ifa;
555 struct in_ifadown_arg arg;
560 arg.rnh = rnh = rt_tables[cpu][AF_INET];
563 rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
564 ifa->ifa_flags &= ~IFA_ROUTE;
568 lwkt_forwardmsg(netisr_cpuport(nextcpu), &rmsg->base.lmsg);
570 lwkt_replymsg(&rmsg->base.lmsg, 0);
574 in_ifadown_force(struct ifaddr *ifa, int delete)
576 struct netmsg_ifadown msg;
578 if (ifa->ifa_addr->sa_family != AF_INET)
582 * XXX individual requests are not independantly chained,
583 * which means that the per-cpu route tables will not be
584 * consistent in the middle of the operation. If routes
585 * related to the interface are manipulated while we are
586 * doing this the inconsistancy could trigger a panic.
588 netmsg_init(&msg.base, NULL, &curthread->td_msgport, MSGF_PRIORITY,
589 in_ifadown_dispatch);
592 rt_domsg_global(&msg.base);
598 in_ifadown(struct ifaddr *ifa, int delete)
601 if (ifa->ifa_ifp->if_type == IFT_CARP)
604 return in_ifadown_force(ifa, delete);