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();
193 * This code is the inverse of in_closeroute: on first reference, if we
194 * were managing the route, stop doing so and set the expiration timer
197 static struct radix_node *
198 in_matchroute(char *key, struct radix_node_head *head)
200 struct radix_node *rn = rn_match(key, head);
201 struct rtentry *rt = (struct rtentry *)rn;
203 if (rt != NULL && rt->rt_refcnt == 0) { /* this is first reference */
204 if (rt->rt_flags & RTPRF_EXPIRING) {
205 rt->rt_flags &= ~RTPRF_EXPIRING;
206 rt->rt_rmx.rmx_expire = 0;
212 static int rtq_reallyold = 60*60; /* one hour is ``really old'' */
213 SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
215 "Default expiration time on cloned routes");
217 static int rtq_minreallyold = 10; /* never automatically crank down to less */
218 SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
219 &rtq_minreallyold , 0,
220 "Minimum time to attempt to hold onto cloned routes");
222 static int rtq_toomany = 128; /* 128 cached routes is ``too many'' */
223 SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
224 &rtq_toomany , 0, "Upper limit on cloned routes");
227 * On last reference drop, mark the route as belong to us so that it can be
231 in_closeroute(struct radix_node *rn, struct radix_node_head *head)
233 struct rtentry *rt = (struct rtentry *)rn;
235 if (!(rt->rt_flags & RTF_UP))
236 return; /* prophylactic measures */
238 if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
241 if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_EXPIRING)) != RTF_WASCLONED)
245 * As requested by David Greenman:
246 * If rtq_reallyold is 0, just delete the route without
247 * waiting for a timeout cycle to kill it.
249 if (rtq_reallyold != 0) {
250 rt->rt_flags |= RTPRF_EXPIRING;
251 rt->rt_rmx.rmx_expire = time_uptime + rtq_reallyold;
254 * Remove route from the radix tree, but defer deallocation
255 * until we return to rtfree().
257 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt),
263 struct radix_node_head *rnh;
272 * Get rid of old routes. When draining, this deletes everything, even when
273 * the timeout is not expired yet. When updating, this makes sure that
274 * nothing has a timeout longer than the current value of rtq_reallyold.
277 in_rtqkill(struct radix_node *rn, void *rock)
279 struct rtqk_arg *ap = rock;
280 struct rtentry *rt = (struct rtentry *)rn;
283 if (rt->rt_flags & RTPRF_EXPIRING) {
285 if (ap->draining || rt->rt_rmx.rmx_expire <= time_uptime) {
286 if (rt->rt_refcnt > 0)
287 panic("rtqkill route really not free");
289 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
290 rt_mask(rt), rt->rt_flags, NULL);
292 log(LOG_WARNING, "in_rtqkill: error %d\n", err);
297 (int)(rt->rt_rmx.rmx_expire - time_uptime) >
299 rt->rt_rmx.rmx_expire = time_uptime +
302 ap->nextstop = lmin(ap->nextstop,
303 rt->rt_rmx.rmx_expire);
310 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
311 static int rtq_timeout = RTQ_TIMEOUT;
315 * 'last_adjusted_timeout' and 'rtq_reallyold' are _not_ read-only, and
316 * could be changed by all CPUs. However, they are changed at so low
317 * frequency that we could ignore the cache trashing issue and take them
321 in_rtqtimo_dispatch(netmsg_t nmsg)
325 static time_t last_adjusted_timeout = 0;
326 struct in_rtq_pcpu *pcpu = &in_rtq_pcpu[mycpuid];
327 struct radix_node_head *rnh = pcpu->rnh;
329 ASSERT_NETISR_NCPUS(mycpuid);
333 lwkt_replymsg(&nmsg->lmsg, 0);
336 arg.found = arg.killed = 0;
338 arg.nextstop = time_uptime + rtq_timeout;
339 arg.draining = arg.updating = 0;
340 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
343 * Attempt to be somewhat dynamic about this:
344 * If there are ``too many'' routes sitting around taking up space,
345 * then crank down the timeout, and see if we can't make some more
346 * go away. However, we make sure that we will never adjust more
347 * than once in rtq_timeout seconds, to keep from cranking down too
350 if ((arg.found - arg.killed > rtq_toomany) &&
351 (int)(time_uptime - last_adjusted_timeout) >= rtq_timeout &&
352 rtq_reallyold > rtq_minreallyold) {
353 rtq_reallyold = 2*rtq_reallyold / 3;
354 if (rtq_reallyold < rtq_minreallyold) {
355 rtq_reallyold = rtq_minreallyold;
358 last_adjusted_timeout = time_uptime;
360 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
363 arg.found = arg.killed = 0;
365 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
369 atv.tv_sec = arg.nextstop - time_uptime;
370 if ((int)atv.tv_sec < 1) { /* time shift safety */
372 arg.nextstop = time_uptime + atv.tv_sec;
374 if ((int)atv.tv_sec > rtq_timeout) { /* time shift safety */
375 atv.tv_sec = rtq_timeout;
376 arg.nextstop = time_uptime + atv.tv_sec;
378 callout_reset(&pcpu->timo_ch, tvtohz_high(&atv), in_rtqtimo, NULL);
382 in_rtqtimo(void *arg __unused)
385 struct lwkt_msg *lmsg = &in_rtq_pcpu[cpuid].timo_nmsg.lmsg;
388 if (lmsg->ms_flags & MSGF_DONE)
389 lwkt_sendmsg_oncpu(netisr_cpuport(cpuid), lmsg);
394 in_rtqdrain_oncpu(struct in_rtq_pcpu *pcpu)
396 struct radix_node_head *rnh = rt_tables[mycpuid][AF_INET];
399 ASSERT_NETISR_NCPUS(mycpuid);
401 arg.found = arg.killed = 0;
406 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
408 pcpu->lastdrain = time_uptime;
412 in_rtqdrain_dispatch(netmsg_t nmsg)
414 struct in_rtq_pcpu *pcpu = &in_rtq_pcpu[mycpuid];
418 lwkt_replymsg(&nmsg->lmsg, 0);
421 in_rtqdrain_oncpu(pcpu);
426 in_rtqdrain_ipi(void *arg __unused)
429 struct lwkt_msg *msg = &in_rtq_pcpu[cpu].drain_nmsg.lmsg;
432 if (msg->ms_flags & MSGF_DONE)
433 lwkt_sendmsg_oncpu(netisr_cpuport(cpu), msg);
443 CPUMASK_ASSBMASK(mask, netisr_ncpus);
444 CPUMASK_ANDMASK(mask, smp_active_mask);
447 if (IN_NETISR_NCPUS(cpu)) {
448 in_rtqdrain_oncpu(&in_rtq_pcpu[cpu]);
449 CPUMASK_NANDBIT(mask, cpu);
452 for (cpu = 0; cpu < netisr_ncpus; ++cpu) {
453 struct in_rtq_pcpu *pcpu = &in_rtq_pcpu[cpu];
455 if (!CPUMASK_TESTBIT(mask, cpu))
458 if (pcpu->draining || pcpu->lastdrain == time_uptime) {
459 /* Just drained or is draining; skip this cpu. */
460 CPUMASK_NANDBIT(mask, cpu);
466 if (CPUMASK_TESTNZERO(mask))
467 lwkt_send_ipiq_mask(mask, in_rtqdrain_ipi, NULL);
471 * Initialize our routing tree.
474 in_inithead(void **head, int off)
476 struct radix_node_head *rnh;
477 struct in_rtq_pcpu *pcpu;
480 KKASSERT(head == (void **)&rt_tables[cpuid][AF_INET]);
482 if (!rn_inithead(head, rn_cpumaskhead(cpuid), off))
486 rnh->rnh_addaddr = in_addroute;
487 rnh->rnh_matchaddr = in_matchroute;
488 rnh->rnh_close = in_closeroute;
490 pcpu = &in_rtq_pcpu[cpuid];
492 callout_init_mp(&pcpu->timo_ch);
493 netmsg_init(&pcpu->timo_nmsg, NULL, &netisr_adone_rport, MSGF_PRIORITY,
494 in_rtqtimo_dispatch);
495 netmsg_init(&pcpu->drain_nmsg, NULL, &netisr_adone_rport, MSGF_PRIORITY,
496 in_rtqdrain_dispatch);
498 in_rtqtimo(NULL); /* kick off timeout first time */
503 * This zaps old routes when the interface goes down or interface
504 * address is deleted. In the latter case, it deletes static routes
505 * that point to this address. If we don't do this, we may end up
506 * using the old address in the future. The ones we always want to
507 * get rid of are things like ARP entries, since the user might down
508 * the interface, walk over to a completely different network, and
511 * in_ifadown() is typically called when an interface is being brought
512 * down. We must iterate through all per-cpu route tables and clean
515 struct in_ifadown_arg {
516 struct radix_node_head *rnh;
522 in_ifadownkill(struct radix_node *rn, void *xap)
524 struct in_ifadown_arg *ap = xap;
525 struct rtentry *rt = (struct rtentry *)rn;
528 if (rt->rt_ifa == ap->ifa &&
529 (ap->del || !(rt->rt_flags & RTF_STATIC))) {
531 * We need to disable the automatic prune that happens
532 * in this case in rtrequest() because it will blow
533 * away the pointers that rn_walktree() needs in order
534 * continue our descent. We will end up deleting all
535 * the routes that rtrequest() would have in any case,
536 * so that behavior is not needed there.
538 rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
539 err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
540 rt_mask(rt), rt->rt_flags, NULL);
542 log(LOG_WARNING, "in_ifadownkill: error %d\n", err);
547 struct netmsg_ifadown {
548 struct netmsg_base base;
554 in_ifadown_dispatch(netmsg_t msg)
556 struct netmsg_ifadown *rmsg = (void *)msg;
557 struct radix_node_head *rnh;
558 struct ifaddr *ifa = rmsg->ifa;
559 struct in_ifadown_arg arg;
563 ASSERT_NETISR_NCPUS(cpu);
565 arg.rnh = rnh = rt_tables[cpu][AF_INET];
568 rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
569 ifa->ifa_flags &= ~IFA_ROUTE;
571 netisr_forwardmsg(&msg->base, cpu + 1);
575 in_ifadown_force(struct ifaddr *ifa, int delete)
577 struct netmsg_ifadown msg;
579 if (ifa->ifa_addr->sa_family != AF_INET)
583 * XXX individual requests are not independantly chained,
584 * which means that the per-cpu route tables will not be
585 * consistent in the middle of the operation. If routes
586 * related to the interface are manipulated while we are
587 * doing this the inconsistancy could trigger a panic.
589 netmsg_init(&msg.base, NULL, &curthread->td_msgport, MSGF_PRIORITY,
590 in_ifadown_dispatch);
593 netisr_domsg_global(&msg.base);
599 in_ifadown(struct ifaddr *ifa, int delete)
602 if (ifa->ifa_ifp->if_type == IFT_CARP)
605 return in_ifadown_force(ifa, delete);