/sys/netinet/in_rmx.c
C | 459 lines | 271 code | 48 blank | 140 comment | 54 complexity | aba4240913a2e0290c224845479bf0b4 MD5 | raw file
- /*
- * Copyright 1994, 1995 Massachusetts Institute of Technology
- *
- * Permission to use, copy, modify, and distribute this software and
- * its documentation for any purpose and without fee is hereby
- * granted, provided that both the above copyright notice and this
- * permission notice appear in all copies, that both the above
- * copyright notice and this permission notice appear in all
- * supporting documentation, and that the name of M.I.T. not be used
- * in advertising or publicity pertaining to distribution of the
- * software without specific, written prior permission. M.I.T. makes
- * no representations about the suitability of this software for any
- * purpose. It is provided "as is" without express or implied
- * warranty.
- *
- * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
- * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
- * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * $FreeBSD: src/sys/netinet/in_rmx.c,v 1.37.2.3 2002/08/09 14:49:23 ru Exp $
- * $DragonFly: src/sys/netinet/in_rmx.c,v 1.14 2006/04/11 06:59:34 dillon Exp $
- */
- /*
- * This code does two things necessary for the enhanced TCP metrics to
- * function in a useful manner:
- * 1) It marks all non-host routes as `cloning', thus ensuring that
- * every actual reference to such a route actually gets turned
- * into a reference to a host route to the specific destination
- * requested.
- * 2) When such routes lose all their references, it arranges for them
- * to be deleted in some random collection of circumstances, so that
- * a large quantity of stale routing data is not kept in kernel memory
- * indefinitely. See in_rtqtimo() below for the exact mechanism.
- */
- #include <sys/param.h>
- #include <sys/systm.h>
- #include <sys/kernel.h>
- #include <sys/sysctl.h>
- #include <sys/socket.h>
- #include <sys/mbuf.h>
- #include <sys/syslog.h>
- #include <sys/globaldata.h>
- #include <sys/thread2.h>
- #include <net/if.h>
- #include <net/route.h>
- #include <net/if_var.h>
- #include <netinet/in.h>
- #include <netinet/in_var.h>
- #include <netinet/ip_var.h>
- #include <netinet/ip_flow.h>
- #define RTPRF_EXPIRING RTF_PROTO3 /* set on routes we manage */
- static struct callout in_rtqtimo_ch[MAXCPU];
- /*
- * Do what we need to do when inserting a route.
- */
- static struct radix_node *
- in_addroute(char *key, char *mask, struct radix_node_head *head,
- struct radix_node *treenodes)
- {
- struct rtentry *rt = (struct rtentry *)treenodes;
- struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
- struct radix_node *ret;
- struct in_ifaddr_container *iac;
- struct in_ifaddr *ia;
- /*
- * For IP, mark routes to multicast addresses as such, because
- * it's easy to do and might be useful (but this is much more
- * dubious since it's so easy to inspect the address).
- *
- * For IP, all unicast non-host routes are automatically cloning.
- */
- if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
- rt->rt_flags |= RTF_MULTICAST;
- if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST)))
- rt->rt_flags |= RTF_PRCLONING;
- /*
- * For host routes, we make sure that RTF_BROADCAST
- * is set for anything that looks like a broadcast address.
- * This way, we can avoid an expensive call to in_broadcast()
- * in ip_output() most of the time (because the route passed
- * to ip_output() is almost always a host route).
- *
- * For local routes we set RTF_LOCAL allowing various shortcuts.
- *
- * A cloned network route will point to one of several possible
- * addresses if an interface has aliases and must be repointed
- * back to the correct address or arp_rtrequest() will not properly
- * detect the local ip.
- */
- if (rt->rt_flags & RTF_HOST) {
- if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
- rt->rt_flags |= RTF_BROADCAST;
- } else if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr ==
- sin->sin_addr.s_addr) {
- rt->rt_flags |= RTF_LOCAL;
- } else {
- LIST_FOREACH(iac, INADDR_HASH(sin->sin_addr.s_addr),
- ia_hash) {
- ia = iac->ia;
- if (sin->sin_addr.s_addr ==
- ia->ia_addr.sin_addr.s_addr) {
- rt->rt_flags |= RTF_LOCAL;
- IFAREF(&ia->ia_ifa);
- IFAFREE(rt->rt_ifa);
- rt->rt_ifa = &ia->ia_ifa;
- rt->rt_ifp = rt->rt_ifa->ifa_ifp;
- break;
- }
- }
- }
- }
- if (rt->rt_rmx.rmx_mtu != 0 && !(rt->rt_rmx.rmx_locks & RTV_MTU) &&
- rt->rt_ifp != NULL)
- rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
- ret = rn_addroute(key, mask, head, treenodes);
- if (ret == NULL && (rt->rt_flags & RTF_HOST)) {
- struct rtentry *oldrt;
- /*
- * We are trying to add a host route, but can't.
- * Find out if it is because of an ARP entry and
- * delete it if so.
- */
- oldrt = rtpurelookup((struct sockaddr *)sin);
- if (oldrt != NULL) {
- --oldrt->rt_refcnt;
- if ((oldrt->rt_flags & RTF_LLINFO) &&
- (oldrt->rt_flags & RTF_HOST) &&
- oldrt->rt_gateway &&
- oldrt->rt_gateway->sa_family == AF_LINK) {
- rtrequest(RTM_DELETE, rt_key(oldrt),
- oldrt->rt_gateway, rt_mask(oldrt),
- oldrt->rt_flags, NULL);
- ret = rn_addroute(key, mask, head, treenodes);
- }
- }
- }
- /*
- * If the new route has been created successfully, and it is
- * not a multicast/broadcast or cloned route, then we will
- * have to flush the ipflow. Otherwise, we may end up using
- * the wrong route.
- */
- if (ret != NULL &&
- (rt->rt_flags &
- (RTF_MULTICAST | RTF_BROADCAST | RTF_WASCLONED)) == 0) {
- ipflow_flush_oncpu();
- }
- return ret;
- }
- /*
- * This code is the inverse of in_closeroute: on first reference, if we
- * were managing the route, stop doing so and set the expiration timer
- * back off again.
- */
- static struct radix_node *
- in_matchroute(char *key, struct radix_node_head *head)
- {
- struct radix_node *rn = rn_match(key, head);
- struct rtentry *rt = (struct rtentry *)rn;
- if (rt != NULL && rt->rt_refcnt == 0) { /* this is first reference */
- if (rt->rt_flags & RTPRF_EXPIRING) {
- rt->rt_flags &= ~RTPRF_EXPIRING;
- rt->rt_rmx.rmx_expire = 0;
- }
- }
- return rn;
- }
- static int rtq_reallyold = 60*60; /* one hour is ``really old'' */
- SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
- &rtq_reallyold , 0,
- "Default expiration time on cloned routes");
- static int rtq_minreallyold = 10; /* never automatically crank down to less */
- SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
- &rtq_minreallyold , 0,
- "Minimum time to attempt to hold onto cloned routes");
- static int rtq_toomany = 128; /* 128 cached routes is ``too many'' */
- SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
- &rtq_toomany , 0, "Upper limit on cloned routes");
- /*
- * On last reference drop, mark the route as belong to us so that it can be
- * timed out.
- */
- static void
- in_closeroute(struct radix_node *rn, struct radix_node_head *head)
- {
- struct rtentry *rt = (struct rtentry *)rn;
- if (!(rt->rt_flags & RTF_UP))
- return; /* prophylactic measures */
- if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
- return;
- if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_EXPIRING)) != RTF_WASCLONED)
- return;
- /*
- * As requested by David Greenman:
- * If rtq_reallyold is 0, just delete the route without
- * waiting for a timeout cycle to kill it.
- */
- if (rtq_reallyold != 0) {
- rt->rt_flags |= RTPRF_EXPIRING;
- rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
- } else {
- /*
- * Remove route from the radix tree, but defer deallocation
- * until we return to rtfree().
- */
- rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt),
- rt->rt_flags, &rt);
- }
- }
- struct rtqk_arg {
- struct radix_node_head *rnh;
- int draining;
- int killed;
- int found;
- int updating;
- time_t nextstop;
- };
- /*
- * Get rid of old routes. When draining, this deletes everything, even when
- * the timeout is not expired yet. When updating, this makes sure that
- * nothing has a timeout longer than the current value of rtq_reallyold.
- */
- static int
- in_rtqkill(struct radix_node *rn, void *rock)
- {
- struct rtqk_arg *ap = rock;
- struct rtentry *rt = (struct rtentry *)rn;
- int err;
- if (rt->rt_flags & RTPRF_EXPIRING) {
- ap->found++;
- if (ap->draining || rt->rt_rmx.rmx_expire <= time_second) {
- if (rt->rt_refcnt > 0)
- panic("rtqkill route really not free");
- err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
- rt_mask(rt), rt->rt_flags, NULL);
- if (err)
- log(LOG_WARNING, "in_rtqkill: error %d\n", err);
- else
- ap->killed++;
- } else {
- if (ap->updating &&
- (rt->rt_rmx.rmx_expire - time_second >
- rtq_reallyold)) {
- rt->rt_rmx.rmx_expire = time_second +
- rtq_reallyold;
- }
- ap->nextstop = lmin(ap->nextstop,
- rt->rt_rmx.rmx_expire);
- }
- }
- return 0;
- }
- #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
- static int rtq_timeout = RTQ_TIMEOUT;
- static void
- in_rtqtimo(void *rock)
- {
- struct radix_node_head *rnh = rock;
- struct rtqk_arg arg;
- struct timeval atv;
- static time_t last_adjusted_timeout = 0;
- arg.found = arg.killed = 0;
- arg.rnh = rnh;
- arg.nextstop = time_second + rtq_timeout;
- arg.draining = arg.updating = 0;
- crit_enter();
- rnh->rnh_walktree(rnh, in_rtqkill, &arg);
- crit_exit();
- /*
- * Attempt to be somewhat dynamic about this:
- * If there are ``too many'' routes sitting around taking up space,
- * then crank down the timeout, and see if we can't make some more
- * go away. However, we make sure that we will never adjust more
- * than once in rtq_timeout seconds, to keep from cranking down too
- * hard.
- */
- if ((arg.found - arg.killed > rtq_toomany) &&
- (time_second - last_adjusted_timeout >= rtq_timeout) &&
- rtq_reallyold > rtq_minreallyold) {
- rtq_reallyold = 2*rtq_reallyold / 3;
- if (rtq_reallyold < rtq_minreallyold) {
- rtq_reallyold = rtq_minreallyold;
- }
- last_adjusted_timeout = time_second;
- #ifdef DIAGNOSTIC
- log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
- rtq_reallyold);
- #endif
- arg.found = arg.killed = 0;
- arg.updating = 1;
- crit_enter();
- rnh->rnh_walktree(rnh, in_rtqkill, &arg);
- crit_exit();
- }
- atv.tv_usec = 0;
- atv.tv_sec = arg.nextstop - time_second;
- callout_reset(&in_rtqtimo_ch[mycpuid], tvtohz_high(&atv), in_rtqtimo,
- rock);
- }
- void
- in_rtqdrain(void)
- {
- struct radix_node_head *rnh = rt_tables[mycpuid][AF_INET];
- struct rtqk_arg arg;
- arg.found = arg.killed = 0;
- arg.rnh = rnh;
- arg.nextstop = 0;
- arg.draining = 1;
- arg.updating = 0;
- crit_enter();
- rnh->rnh_walktree(rnh, in_rtqkill, &arg);
- crit_exit();
- }
- /*
- * Initialize our routing tree.
- */
- int
- in_inithead(void **head, int off)
- {
- struct radix_node_head *rnh;
- if (!rn_inithead(head, rn_cpumaskhead(mycpuid), off))
- return 0;
- if (head != (void **)&rt_tables[mycpuid][AF_INET]) /* BOGUS! */
- return 1; /* only do this for the real routing table */
- rnh = *head;
- rnh->rnh_addaddr = in_addroute;
- rnh->rnh_matchaddr = in_matchroute;
- rnh->rnh_close = in_closeroute;
- callout_init(&in_rtqtimo_ch[mycpuid]);
- in_rtqtimo(rnh); /* kick off timeout first time */
- return 1;
- }
- /*
- * This zaps old routes when the interface goes down or interface
- * address is deleted. In the latter case, it deletes static routes
- * that point to this address. If we don't do this, we may end up
- * using the old address in the future. The ones we always want to
- * get rid of are things like ARP entries, since the user might down
- * the interface, walk over to a completely different network, and
- * plug back in.
- *
- * in_ifadown() is typically called when an interface is being brought
- * down. We must iterate through all per-cpu route tables and clean
- * them up.
- */
- struct in_ifadown_arg {
- struct radix_node_head *rnh;
- struct ifaddr *ifa;
- int del;
- };
- static int
- in_ifadownkill(struct radix_node *rn, void *xap)
- {
- struct in_ifadown_arg *ap = xap;
- struct rtentry *rt = (struct rtentry *)rn;
- int err;
- if (rt->rt_ifa == ap->ifa &&
- (ap->del || !(rt->rt_flags & RTF_STATIC))) {
- /*
- * We need to disable the automatic prune that happens
- * in this case in rtrequest() because it will blow
- * away the pointers that rn_walktree() needs in order
- * continue our descent. We will end up deleting all
- * the routes that rtrequest() would have in any case,
- * so that behavior is not needed there.
- */
- rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
- err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
- rt_mask(rt), rt->rt_flags, NULL);
- if (err)
- log(LOG_WARNING, "in_ifadownkill: error %d\n", err);
- }
- return 0;
- }
- int
- in_ifadown(struct ifaddr *ifa, int delete)
- {
- struct in_ifadown_arg arg;
- struct radix_node_head *rnh;
- int origcpu;
- int cpu;
- if (ifa->ifa_addr->sa_family != AF_INET)
- return 1;
- /*
- * XXX individual requests are not independantly chained,
- * which means that the per-cpu route tables will not be
- * consistent in the middle of the operation. If routes
- * related to the interface are manipulated while we are
- * doing this the inconsistancy could trigger a panic.
- */
- origcpu = mycpuid;
- for (cpu = 0; cpu < ncpus; cpu++) {
- lwkt_migratecpu(cpu);
- arg.rnh = rnh = rt_tables[cpu][AF_INET];
- arg.ifa = ifa;
- arg.del = delete;
- rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
- ifa->ifa_flags &= ~IFA_ROUTE;
- }
- lwkt_migratecpu(origcpu);
- return 0;
- }