427 lines
12 KiB
C
427 lines
12 KiB
C
/*
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* Copyright 1994, 1995 Massachusetts Institute of Technology
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose and without fee is hereby
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* granted, provided that both the above copyright notice and this
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* permission notice appear in all copies, that both the above
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* copyright notice and this permission notice appear in all
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* supporting documentation, and that the name of M.I.T. not be used
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* in advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission. M.I.T. makes
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* no representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied
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* warranty.
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*
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* THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
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* ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
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* SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* This code does two things necessary for the enhanced TCP metrics to
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* function in a useful manner:
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* 1) It marks all non-host routes as `cloning', thus ensuring that
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* every actual reference to such a route actually gets turned
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* into a reference to a host route to the specific destination
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* requested.
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* 2) When such routes lose all their references, it arranges for them
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* to be deleted in some random collection of circumstances, so that
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* a large quantity of stale routing data is not kept in kernel memory
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* indefinitely. See in_rtqtimo() below for the exact mechanism.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/socket.h>
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#include <sys/mbuf.h>
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#include <sys/syslog.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_var.h>
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#include <netinet/ip_var.h>
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extern int in_inithead __P((void **head, int off));
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#define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */
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/*
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* Do what we need to do when inserting a route.
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*/
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static struct radix_node *
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in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
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struct radix_node *treenodes)
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{
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struct rtentry *rt = (struct rtentry *)treenodes;
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struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
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struct radix_node *ret;
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/*
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* For IP, all unicast non-host routes are automatically cloning.
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*/
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if(IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
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rt->rt_flags |= RTF_MULTICAST;
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if(!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) {
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rt->rt_flags |= RTF_PRCLONING;
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}
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/*
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* A little bit of help for both IP output and input:
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* For host routes, we make sure that RTF_BROADCAST
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* is set for anything that looks like a broadcast address.
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* This way, we can avoid an expensive call to in_broadcast()
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* in ip_output() most of the time (because the route passed
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* to ip_output() is almost always a host route).
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*
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* We also do the same for local addresses, with the thought
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* that this might one day be used to speed up ip_input().
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*
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* We also mark routes to multicast addresses as such, because
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* it's easy to do and might be useful (but this is much more
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* dubious since it's so easy to inspect the address). (This
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* is done above.)
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*/
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if (rt->rt_flags & RTF_HOST) {
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if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
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rt->rt_flags |= RTF_BROADCAST;
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} else {
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if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr
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== sin->sin_addr.s_addr)
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rt->rt_flags |= RTF_LOCAL;
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}
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}
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if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU)
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&& rt->rt_ifp)
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rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
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ret = rn_addroute(v_arg, n_arg, head, treenodes);
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if (ret == NULL && rt->rt_flags & RTF_HOST) {
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struct rtentry *rt2;
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/*
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* We are trying to add a host route, but can't.
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* Find out if it is because of an
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* ARP entry and delete it if so.
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*/
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rt2 = rtalloc1((struct sockaddr *)sin, 0,
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RTF_CLONING | RTF_PRCLONING);
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if (rt2) {
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if (rt2->rt_flags & RTF_LLINFO &&
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rt2->rt_flags & RTF_HOST &&
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rt2->rt_gateway &&
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rt2->rt_gateway->sa_family == AF_LINK) {
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rtrequest(RTM_DELETE,
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(struct sockaddr *)rt_key(rt2),
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rt2->rt_gateway,
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rt_mask(rt2), rt2->rt_flags, 0);
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ret = rn_addroute(v_arg, n_arg, head,
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treenodes);
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}
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RTFREE(rt2);
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}
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}
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/*
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* If the new route created successfully, and we are forwarding,
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* and there is a cached route, free it. Otherwise, we may end
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* up using the wrong route.
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*/
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if (ret != NULL && ipforwarding && ipforward_rt.ro_rt) {
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RTFREE(ipforward_rt.ro_rt);
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ipforward_rt.ro_rt = 0;
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}
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return ret;
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}
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/*
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* This code is the inverse of in_clsroute: on first reference, if we
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* were managing the route, stop doing so and set the expiration timer
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* back off again.
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*/
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static struct radix_node *
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in_matroute(void *v_arg, struct radix_node_head *head)
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{
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struct radix_node *rn = rn_match(v_arg, head);
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struct rtentry *rt = (struct rtentry *)rn;
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if(rt && rt->rt_refcnt == 0) { /* this is first reference */
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if(rt->rt_flags & RTPRF_OURS) {
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rt->rt_flags &= ~RTPRF_OURS;
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rt->rt_rmx.rmx_expire = 0;
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}
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}
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return rn;
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}
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static int rtq_reallyold = 60*60;
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/* one hour is ``really old'' */
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SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
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&rtq_reallyold , 0,
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"Default expiration time on dynamically learned routes");
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static int rtq_minreallyold = 10;
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/* never automatically crank down to less */
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SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
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&rtq_minreallyold , 0,
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"Minimum time to attempt to hold onto dynamically learned routes");
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static int rtq_toomany = 128;
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/* 128 cached routes is ``too many'' */
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SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
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&rtq_toomany , 0, "Upper limit on dynamically learned routes");
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/*
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* On last reference drop, mark the route as belong to us so that it can be
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* timed out.
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*/
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static void
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in_clsroute(struct radix_node *rn, struct radix_node_head *head)
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{
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struct rtentry *rt = (struct rtentry *)rn;
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if(!(rt->rt_flags & RTF_UP))
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return; /* prophylactic measures */
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if((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
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return;
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if((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS))
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!= RTF_WASCLONED)
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return;
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/*
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* As requested by David Greenman:
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* If rtq_reallyold is 0, just delete the route without
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* waiting for a timeout cycle to kill it.
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*/
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if(rtq_reallyold != 0) {
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rt->rt_flags |= RTPRF_OURS;
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rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
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} else {
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rtrequest(RTM_DELETE,
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(struct sockaddr *)rt_key(rt),
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rt->rt_gateway, rt_mask(rt),
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rt->rt_flags, 0);
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}
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}
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struct rtqk_arg {
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struct radix_node_head *rnh;
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int draining;
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int killed;
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int found;
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int updating;
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time_t nextstop;
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};
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/*
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* Get rid of old routes. When draining, this deletes everything, even when
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* the timeout is not expired yet. When updating, this makes sure that
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* nothing has a timeout longer than the current value of rtq_reallyold.
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*/
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static int
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in_rtqkill(struct radix_node *rn, void *rock)
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{
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struct rtqk_arg *ap = rock;
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struct rtentry *rt = (struct rtentry *)rn;
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int err;
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if(rt->rt_flags & RTPRF_OURS) {
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ap->found++;
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if(ap->draining || rt->rt_rmx.rmx_expire <= time_second) {
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if(rt->rt_refcnt > 0)
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panic("rtqkill route really not free");
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err = rtrequest(RTM_DELETE,
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(struct sockaddr *)rt_key(rt),
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rt->rt_gateway, rt_mask(rt),
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rt->rt_flags, 0);
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if(err) {
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log(LOG_WARNING, "in_rtqkill: error %d\n", err);
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} else {
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ap->killed++;
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}
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} else {
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if(ap->updating
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&& (rt->rt_rmx.rmx_expire - time_second
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> rtq_reallyold)) {
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rt->rt_rmx.rmx_expire = time_second
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+ rtq_reallyold;
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}
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ap->nextstop = lmin(ap->nextstop,
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rt->rt_rmx.rmx_expire);
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}
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}
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return 0;
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}
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#define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
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static int rtq_timeout = RTQ_TIMEOUT;
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static void
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in_rtqtimo(void *rock)
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{
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struct radix_node_head *rnh = rock;
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struct rtqk_arg arg;
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struct timeval atv;
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static time_t last_adjusted_timeout = 0;
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int s;
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arg.found = arg.killed = 0;
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arg.rnh = rnh;
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arg.nextstop = time_second + rtq_timeout;
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arg.draining = arg.updating = 0;
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s = splnet();
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rnh->rnh_walktree(rnh, in_rtqkill, &arg);
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splx(s);
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/*
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* Attempt to be somewhat dynamic about this:
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* If there are ``too many'' routes sitting around taking up space,
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* then crank down the timeout, and see if we can't make some more
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* go away. However, we make sure that we will never adjust more
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* than once in rtq_timeout seconds, to keep from cranking down too
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* hard.
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*/
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if((arg.found - arg.killed > rtq_toomany)
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&& (time_second - last_adjusted_timeout >= rtq_timeout)
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&& rtq_reallyold > rtq_minreallyold) {
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rtq_reallyold = 2*rtq_reallyold / 3;
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if(rtq_reallyold < rtq_minreallyold) {
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rtq_reallyold = rtq_minreallyold;
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}
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last_adjusted_timeout = time_second;
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#ifdef DIAGNOSTIC
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log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
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rtq_reallyold);
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#endif
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arg.found = arg.killed = 0;
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arg.updating = 1;
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s = splnet();
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rnh->rnh_walktree(rnh, in_rtqkill, &arg);
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splx(s);
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}
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atv.tv_usec = 0;
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atv.tv_sec = arg.nextstop - time_second;
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timeout(in_rtqtimo, rock, tvtohz(&atv));
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}
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void
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in_rtqdrain(void)
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{
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struct radix_node_head *rnh = rt_tables[AF_INET];
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struct rtqk_arg arg;
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int s;
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arg.found = arg.killed = 0;
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arg.rnh = rnh;
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arg.nextstop = 0;
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arg.draining = 1;
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arg.updating = 0;
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s = splnet();
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rnh->rnh_walktree(rnh, in_rtqkill, &arg);
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splx(s);
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}
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/*
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* Initialize our routing tree.
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*/
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int
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in_inithead(void **head, int off)
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{
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struct radix_node_head *rnh;
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if(!rn_inithead(head, off))
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return 0;
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if(head != (void **)&rt_tables[AF_INET]) /* BOGUS! */
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return 1; /* only do this for the real routing table */
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rnh = *head;
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rnh->rnh_addaddr = in_addroute;
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rnh->rnh_matchaddr = in_matroute;
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rnh->rnh_close = in_clsroute;
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in_rtqtimo(rnh); /* kick off timeout first time */
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return 1;
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}
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/*
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* This zaps old routes when the interface goes down or interface
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* address is deleted. In the latter case, it deletes static routes
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* that point to this address. If we don't do this, we may end up
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* using the old address in the future. The ones we always want to
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* get rid of are things like ARP entries, since the user might down
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* the interface, walk over to a completely different network, and
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* plug back in.
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*/
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struct in_ifadown_arg {
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struct radix_node_head *rnh;
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struct ifaddr *ifa;
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int del;
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};
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static int
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in_ifadownkill(struct radix_node *rn, void *xap)
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{
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struct in_ifadown_arg *ap = xap;
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struct rtentry *rt = (struct rtentry *)rn;
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int err;
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if (rt->rt_ifa == ap->ifa &&
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(ap->del || !(rt->rt_flags & RTF_STATIC))) {
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/*
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* We need to disable the automatic prune that happens
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* in this case in rtrequest() because it will blow
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* away the pointers that rn_walktree() needs in order
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* continue our descent. We will end up deleting all
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* the routes that rtrequest() would have in any case,
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* so that behavior is not needed there.
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*/
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rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
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err = rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt),
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rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
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if (err) {
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log(LOG_WARNING, "in_ifadownkill: error %d\n", err);
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}
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}
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return 0;
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}
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int
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in_ifadown(struct ifaddr *ifa, int delete)
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{
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struct in_ifadown_arg arg;
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struct radix_node_head *rnh;
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if (ifa->ifa_addr->sa_family != AF_INET)
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return 1;
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arg.rnh = rnh = rt_tables[AF_INET];
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arg.ifa = ifa;
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arg.del = delete;
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rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
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ifa->ifa_flags &= ~IFA_ROUTE;
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return 0;
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}
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