/* * 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 1.8 2005/01/01 09:20:05 hsu 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 #include #include #include #include #include #include #include #include #include #include #include #define RTPRF_EXPIRING RTF_PROTO3 /* set on routes we manage */ static struct callout in_rtqtimo_ch; /* * 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; /* * 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; /* * A little bit of help for both IP output and input: * 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). * * We also do the same for local addresses, with the thought * that this might one day be used to speed up ip_input(). * * We also 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). (This * is done above.) */ 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; } } 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 *rt2; /* * 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. */ rt2 = rtlookup((struct sockaddr *)sin, 0, RTF_CLONING | RTF_PRCLONING); if (rt2) { --rt->rt_refcnt; if (rt2->rt_flags & RTF_LLINFO && rt2->rt_flags & RTF_HOST && rt2->rt_gateway && rt2->rt_gateway->sa_family == AF_LINK) { rtrequest(RTM_DELETE, rt_key(rt2), rt2->rt_gateway, rt_mask(rt2), rt2->rt_flags, NULL); ret = rn_addroute(key, mask, head, treenodes); } } } /* * If the new route created successfully, and we are forwarding, * and there is a cached route, free it. Otherwise, we may end * up using the wrong route. */ if (ret != NULL && ipforwarding && ipforward_rt.ro_rt != NULL) { RTFREE(ipforward_rt.ro_rt); ipforward_rt.ro_rt = NULL; } 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; int s; arg.found = arg.killed = 0; arg.rnh = rnh; arg.nextstop = time_second + rtq_timeout; arg.draining = arg.updating = 0; s = splnet(); rnh->rnh_walktree(rnh, in_rtqkill, &arg); splx(s); /* * 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; s = splnet(); rnh->rnh_walktree(rnh, in_rtqkill, &arg); splx(s); } atv.tv_usec = 0; atv.tv_sec = arg.nextstop - time_second; callout_reset(&in_rtqtimo_ch, tvtohz_high(&atv), in_rtqtimo, rock); } void in_rtqdrain(void) { struct radix_node_head *rnh = rt_tables[AF_INET]; struct rtqk_arg arg; int s; arg.found = arg.killed = 0; arg.rnh = rnh; arg.nextstop = 0; arg.draining = 1; arg.updating = 0; s = splnet(); rnh->rnh_walktree(rnh, in_rtqkill, &arg); splx(s); } /* * Initialize our routing tree. */ int in_inithead(void **head, int off) { struct radix_node_head *rnh; if (!rn_inithead(head, off)) return 0; if (head != (void **)&rt_tables[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); 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. */ 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; if (ifa->ifa_addr->sa_family != AF_INET) return 1; arg.rnh = rnh = rt_tables[AF_INET]; arg.ifa = ifa; arg.del = delete; rnh->rnh_walktree(rnh, in_ifadownkill, &arg); ifa->ifa_flags &= ~IFA_ROUTE; return 0; }