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[/] [or1k/] [trunk/] [rtems/] [c/] [src/] [libnetworking/] [netinet/] [in_rmx.c] - Blame information for rev 1765

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/*
 * 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.
 *
 * $Id: in_rmx.c,v 1.2 2001-09-27 12:01:55 chris 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/queue.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>
 
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
 
#include <netinet/ip.h>
#include <netinet/ip_var.h>
 
#include <netinet/tcp.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
 
extern int      in_inithead __P((void **head, int off));
 
#define RTPRF_OURS              RTF_PROTO3      /* set on routes we manage */
 
/*
 * Do what we need to do when inserting a route.
 */
static struct radix_node *
in_addroute(void *v_arg, void *n_arg, 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 {
#define satosin(sa) ((struct sockaddr_in *)sa)
                        if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr
                            == sin->sin_addr.s_addr)
                                rt->rt_flags |= RTF_LOCAL;
#undef satosin
                }
        }
 
        /*
         * We also specify a send and receive pipe size for every
         * route added, to help TCP a bit.  TCP doesn't actually
         * want a true pipe size, which would be prohibitive in memory
         * costs and is hard to compute anyway; it simply uses these
         * values to size its buffers.  So, we fill them in with the
         * same values that TCP would have used anyway, and allow the
         * installing program or the link layer to override these values
         * as it sees fit.  This will hopefully allow TCP more
         * opportunities to save its ssthresh value.
         */
        if (!rt->rt_rmx.rmx_sendpipe && !(rt->rt_rmx.rmx_locks & RTV_SPIPE))
                rt->rt_rmx.rmx_sendpipe = tcp_sendspace;
 
        if (!rt->rt_rmx.rmx_recvpipe && !(rt->rt_rmx.rmx_locks & RTV_RPIPE))
                rt->rt_rmx.rmx_recvpipe = tcp_recvspace;
 
        if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU)
            && rt->rt_ifp)
                rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
 
        ret = rn_addroute(v_arg, n_arg, 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 = rtalloc1((struct sockaddr *)sin, 0,
                                RTF_CLONING | RTF_PRCLONING);
                if (rt2) {
                        if (rt2->rt_flags & RTF_LLINFO &&
                                rt2->rt_flags & RTF_HOST &&
                                rt2->rt_gateway &&
                                rt2->rt_gateway->sa_family == AF_LINK) {
                                rtrequest(RTM_DELETE,
                                          (struct sockaddr *)rt_key(rt2),
                                          rt2->rt_gateway,
                                          rt_mask(rt2), rt2->rt_flags, 0);
                                ret = rn_addroute(v_arg, n_arg, head,
                                        treenodes);
                        }
                        RTFREE(rt2);
                }
        }
        return ret;
}
 
/*
 * This code is the inverse of in_clsroute: 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_matroute(void *v_arg, struct radix_node_head *head)
{
        struct radix_node *rn = rn_match(v_arg, head);
        struct rtentry *rt = (struct rtentry *)rn;
 
        if(rt && rt->rt_refcnt == 0) { /* this is first reference */
                if(rt->rt_flags & RTPRF_OURS) {
                        rt->rt_flags &= ~RTPRF_OURS;
                        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, "");
 
static int rtq_minreallyold = 10;
        /* never automatically crank down to less */
SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire,
        CTLFLAG_RW, &rtq_minreallyold , 0, "");
 
static int rtq_toomany = 128;
        /* 128 cached routes is ``too many'' */
SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache,
        CTLFLAG_RW, &rtq_toomany , 0, "");
 
 
/*
 * On last reference drop, mark the route as belong to us so that it can be
 * timed out.
 */
static void
in_clsroute(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_OURS))
           != 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_OURS;
                rt->rt_rmx.rmx_expire = rtems_bsdnet_seconds_since_boot() + rtq_reallyold;
        } else {
                rtrequest(RTM_DELETE,
                          (struct sockaddr *)rt_key(rt),
                          rt->rt_gateway, rt_mask(rt),
                          rt->rt_flags, 0);
        }
}
 
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_OURS) {
                ap->found++;
 
                if(ap->draining || rt->rt_rmx.rmx_expire <= rtems_bsdnet_seconds_since_boot()) {
                        if(rt->rt_refcnt > 0)
                                panic("rtqkill route really not free");
 
                        err = rtrequest(RTM_DELETE,
                                        (struct sockaddr *)rt_key(rt),
                                        rt->rt_gateway, rt_mask(rt),
                                        rt->rt_flags, 0);
                        if(err) {
                                log(LOG_WARNING, "in_rtqkill: error %d\n", err);
                        } else {
                                ap->killed++;
                        }
                } else {
                        if(ap->updating
                           && (rt->rt_rmx.rmx_expire - rtems_bsdnet_seconds_since_boot()
                               > rtq_reallyold)) {
                                rt->rt_rmx.rmx_expire = rtems_bsdnet_seconds_since_boot()
                                        + 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 = rtems_bsdnet_seconds_since_boot() + 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)
           && (rtems_bsdnet_seconds_since_boot() - 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 = rtems_bsdnet_seconds_since_boot();
#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;
        timeout(in_rtqtimo, rock, hzto(&atv));
}
 
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_matroute;
        rnh->rnh_close = in_clsroute;
        in_rtqtimo(rnh);        /* kick off timeout first time */
        return 1;
}
 

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[/] [or1k/] [trunk/] [rtems/] [c/] [src/] [libnetworking/] [netinet/] [in_rmx.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	158	chris	`/*`
2			`* Copyright 1994, 1995 Massachusetts Institute of Technology`
3			`*`
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`
7			`* permission notice appear in all copies, that both the above`
8			`* copyright notice and this permission notice appear in all`
9			`* supporting documentation, and that the name of M.I.T. not be used`
10			`* in advertising or publicity pertaining to distribution of the`
11			`* software without specific, written prior permission. M.I.T. makes`
12			`* no representations about the suitability of this software for any`
13			`* purpose. It is provided "as is" without express or implied`
14			`* warranty.`
15			`*`
16			* THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
17			`* ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,`
18			`* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF`
19			`* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT`
20			`* SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,`
21			`* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT`
22			`* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF`
23			`* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND`
24			`* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,`
25			`* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT`
26			`* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
27			`* SUCH DAMAGE.`
28			`*`
29	208	chris	`* $Id: in_rmx.c,v 1.2 2001-09-27 12:01:55 chris Exp $`
30	158	chris	`*/`
31
32			`/*`
33			`* This code does two things necessary for the enhanced TCP metrics to`
34			`* function in a useful manner:`
35			* 1) It marks all non-host routes as `cloning', thus ensuring that
36			`* every actual reference to such a route actually gets turned`
37			`* into a reference to a host route to the specific destination`
38			`* requested.`
39			`* 2) When such routes lose all their references, it arranges for them`
40			`* to be deleted in some random collection of circumstances, so that`
41			`* a large quantity of stale routing data is not kept in kernel memory`
42			`* indefinitely. See in_rtqtimo() below for the exact mechanism.`
43			`*/`
44
45			`#include <sys/param.h>`
46			`#include <sys/systm.h>`
47			`#include <sys/kernel.h>`
48			`#include <sys/sysctl.h>`
49			`#include <sys/queue.h>`
50			`#include <sys/socket.h>`
51			`#include <sys/socketvar.h>`
52			`#include <sys/mbuf.h>`
53			`#include <sys/syslog.h>`
54
55			`#include <net/if.h>`
56			`#include <net/route.h>`
57			`#include <netinet/in.h>`
58			`#include <netinet/in_systm.h>`
59			`#include <netinet/in_var.h>`
60
61			`#include <netinet/ip.h>`
62			`#include <netinet/ip_var.h>`
63
64			`#include <netinet/tcp.h>`
65			`#include <netinet/tcp_seq.h>`
66			`#include <netinet/tcp_timer.h>`
67			`#include <netinet/tcp_var.h>`
68
69			`extern int in_inithead __P((void **head, int off));`
70
71			`#define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */`
72
73			`/*`
74			`* Do what we need to do when inserting a route.`
75			`*/`
76			`static struct radix_node *`
77			`in_addroute(void v_arg, void n_arg, struct radix_node_head *head,`
78			`struct radix_node *treenodes)`
79			`{`
80			`struct rtentry rt = (struct rtentry )treenodes;`
81			`struct sockaddr_in sin = (struct sockaddr_in )rt_key(rt);`
82			`struct radix_node *ret;`
83
84			`/*`
85			`* For IP, all unicast non-host routes are automatically cloning.`
86			`*/`
87			`if(IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))`
88			`rt->rt_flags \|= RTF_MULTICAST;`
89
90			`if(!(rt->rt_flags & (RTF_HOST \| RTF_CLONING \| RTF_MULTICAST))) {`
91			`rt->rt_flags \|= RTF_PRCLONING;`
92			`}`
93
94			`/*`
95			`* A little bit of help for both IP output and input:`
96			`* For host routes, we make sure that RTF_BROADCAST`
97			`* is set for anything that looks like a broadcast address.`
98			`* This way, we can avoid an expensive call to in_broadcast()`
99			`* in ip_output() most of the time (because the route passed`
100			`* to ip_output() is almost always a host route).`
101			`*`
102			`* We also do the same for local addresses, with the thought`
103			`* that this might one day be used to speed up ip_input().`
104			`*`
105			`* We also mark routes to multicast addresses as such, because`
106			`* it's easy to do and might be useful (but this is much more`
107			`* dubious since it's so easy to inspect the address). (This`
108			`* is done above.)`
109			`*/`
110			`if (rt->rt_flags & RTF_HOST) {`
111			`if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {`
112			`rt->rt_flags \|= RTF_BROADCAST;`
113			`} else {`
114			`#define satosin(sa) ((struct sockaddr_in *)sa)`
115			`if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr`
116			`== sin->sin_addr.s_addr)`
117			`rt->rt_flags \|= RTF_LOCAL;`
118			`#undef satosin`
119			`}`
120			`}`
121
122			`/*`
123			`* We also specify a send and receive pipe size for every`
124			`* route added, to help TCP a bit. TCP doesn't actually`
125			`* want a true pipe size, which would be prohibitive in memory`
126			`* costs and is hard to compute anyway; it simply uses these`
127			`* values to size its buffers. So, we fill them in with the`
128			`* same values that TCP would have used anyway, and allow the`
129			`* installing program or the link layer to override these values`
130			`* as it sees fit. This will hopefully allow TCP more`
131			`* opportunities to save its ssthresh value.`
132			`*/`
133			`if (!rt->rt_rmx.rmx_sendpipe && !(rt->rt_rmx.rmx_locks & RTV_SPIPE))`
134			`rt->rt_rmx.rmx_sendpipe = tcp_sendspace;`
135
136			`if (!rt->rt_rmx.rmx_recvpipe && !(rt->rt_rmx.rmx_locks & RTV_RPIPE))`
137			`rt->rt_rmx.rmx_recvpipe = tcp_recvspace;`
138
139			`if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU)`
140			`&& rt->rt_ifp)`
141			`rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;`
142
143			`ret = rn_addroute(v_arg, n_arg, head, treenodes);`
144			`if (ret == NULL && rt->rt_flags & RTF_HOST) {`
145			`struct rtentry *rt2;`
146			`/*`
147			`* We are trying to add a host route, but can't.`
148			`* Find out if it is because of an`
149			`* ARP entry and delete it if so.`
150			`*/`
151			`rt2 = rtalloc1((struct sockaddr *)sin, 0,`
152			`RTF_CLONING \| RTF_PRCLONING);`
153			`if (rt2) {`
154			`if (rt2->rt_flags & RTF_LLINFO &&`
155			`rt2->rt_flags & RTF_HOST &&`
156			`rt2->rt_gateway &&`
157			`rt2->rt_gateway->sa_family == AF_LINK) {`
158			`rtrequest(RTM_DELETE,`
159			`(struct sockaddr *)rt_key(rt2),`
160			`rt2->rt_gateway,`
161			`rt_mask(rt2), rt2->rt_flags, 0);`
162			`ret = rn_addroute(v_arg, n_arg, head,`
163			`treenodes);`
164			`}`
165			`RTFREE(rt2);`
166			`}`
167			`}`
168			`return ret;`
169			`}`
170
171			`/*`
172			`* This code is the inverse of in_clsroute: on first reference, if we`
173			`* were managing the route, stop doing so and set the expiration timer`
174			`* back off again.`
175			`*/`
176			`static struct radix_node *`
177			`in_matroute(void v_arg, struct radix_node_head head)`
178			`{`
179			`struct radix_node *rn = rn_match(v_arg, head);`
180			`struct rtentry rt = (struct rtentry )rn;`
181
182			`if(rt && rt->rt_refcnt == 0) { /* this is first reference */`
183			`if(rt->rt_flags & RTPRF_OURS) {`
184			`rt->rt_flags &= ~RTPRF_OURS;`
185			`rt->rt_rmx.rmx_expire = 0;`
186			`}`
187			`}`
188			`return rn;`
189			`}`
190
191			`static int rtq_reallyold = 60*60;`
192			/* one hour is ``really old'' */
193			`SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire,`
194			`CTLFLAG_RW, &rtq_reallyold , 0, "");`
195
196			`static int rtq_minreallyold = 10;`
197			`/* never automatically crank down to less */`
198			`SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire,`
199			`CTLFLAG_RW, &rtq_minreallyold , 0, "");`
200
201			`static int rtq_toomany = 128;`
202			/* 128 cached routes is ``too many'' */
203			`SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache,`
204			`CTLFLAG_RW, &rtq_toomany , 0, "");`
205
206
207			`/*`
208			`* On last reference drop, mark the route as belong to us so that it can be`
209			`* timed out.`
210			`*/`
211			`static void`
212			`in_clsroute(struct radix_node rn, struct radix_node_head head)`
213			`{`
214			`struct rtentry rt = (struct rtentry )rn;`
215
216			`if(!(rt->rt_flags & RTF_UP))`
217			`return; /* prophylactic measures */`
218
219			`if((rt->rt_flags & (RTF_LLINFO \| RTF_HOST)) != RTF_HOST)`
220			`return;`
221
222			`if((rt->rt_flags & (RTF_WASCLONED \| RTPRF_OURS))`
223			`!= RTF_WASCLONED)`
224			`return;`
225
226			`/*`
227			`* As requested by David Greenman:`
228			`* If rtq_reallyold is 0, just delete the route without`
229			`* waiting for a timeout cycle to kill it.`
230			`*/`
231			`if(rtq_reallyold != 0) {`
232			`rt->rt_flags \|= RTPRF_OURS;`
233			`rt->rt_rmx.rmx_expire = rtems_bsdnet_seconds_since_boot() + rtq_reallyold;`
234			`} else {`
235			`rtrequest(RTM_DELETE,`
236			`(struct sockaddr *)rt_key(rt),`
237			`rt->rt_gateway, rt_mask(rt),`
238			`rt->rt_flags, 0);`
239			`}`
240			`}`
241
242			`struct rtqk_arg {`
243			`struct radix_node_head *rnh;`
244			`int draining;`
245			`int killed;`
246			`int found;`
247			`int updating;`
248			`time_t nextstop;`
249			`};`
250
251			`/*`
252			`* Get rid of old routes. When draining, this deletes everything, even when`
253			`* the timeout is not expired yet. When updating, this makes sure that`
254			`* nothing has a timeout longer than the current value of rtq_reallyold.`
255			`*/`
256			`static int`
257			`in_rtqkill(struct radix_node rn, void rock)`
258			`{`
259			`struct rtqk_arg *ap = rock;`
260			`struct rtentry rt = (struct rtentry )rn;`
261			`int err;`
262
263			`if(rt->rt_flags & RTPRF_OURS) {`
264			`ap->found++;`
265
266			`if(ap->draining \|\| rt->rt_rmx.rmx_expire <= rtems_bsdnet_seconds_since_boot()) {`
267			`if(rt->rt_refcnt > 0)`
268			`panic("rtqkill route really not free");`
269
270			`err = rtrequest(RTM_DELETE,`
271			`(struct sockaddr *)rt_key(rt),`
272			`rt->rt_gateway, rt_mask(rt),`
273			`rt->rt_flags, 0);`
274			`if(err) {`
275			`log(LOG_WARNING, "in_rtqkill: error %d\n", err);`
276			`} else {`
277			`ap->killed++;`
278			`}`
279			`} else {`
280			`if(ap->updating`
281			`&& (rt->rt_rmx.rmx_expire - rtems_bsdnet_seconds_since_boot()`
282			`> rtq_reallyold)) {`
283			`rt->rt_rmx.rmx_expire = rtems_bsdnet_seconds_since_boot()`
284			`+ rtq_reallyold;`
285			`}`
286			`ap->nextstop = lmin(ap->nextstop,`
287			`rt->rt_rmx.rmx_expire);`
288			`}`
289			`}`
290
291			`return 0;`
292			`}`
293
294			`#define RTQ_TIMEOUT 6010 / run no less than once every ten minutes */`
295			`static int rtq_timeout = RTQ_TIMEOUT;`
296
297			`static void`
298			`in_rtqtimo(void *rock)`
299			`{`
300			`struct radix_node_head *rnh = rock;`
301			`struct rtqk_arg arg;`
302			`struct timeval atv;`
303			`static time_t last_adjusted_timeout = 0;`
304			`int s;`
305
306			`arg.found = arg.killed = 0;`
307			`arg.rnh = rnh;`
308			`arg.nextstop = rtems_bsdnet_seconds_since_boot() + rtq_timeout;`
309			`arg.draining = arg.updating = 0;`
310			`s = splnet();`
311			`rnh->rnh_walktree(rnh, in_rtqkill, &arg);`
312			`splx(s);`
313
314			`/*`
315			`* Attempt to be somewhat dynamic about this:`
316			* If there are ``too many'' routes sitting around taking up space,
317			`* then crank down the timeout, and see if we can't make some more`
318			`* go away. However, we make sure that we will never adjust more`
319			`* than once in rtq_timeout seconds, to keep from cranking down too`
320			`* hard.`
321			`*/`
322			`if((arg.found - arg.killed > rtq_toomany)`
323			`&& (rtems_bsdnet_seconds_since_boot() - last_adjusted_timeout >= rtq_timeout)`
324			`&& rtq_reallyold > rtq_minreallyold) {`
325			`rtq_reallyold = 2*rtq_reallyold / 3;`
326			`if(rtq_reallyold < rtq_minreallyold) {`
327			`rtq_reallyold = rtq_minreallyold;`
328			`}`
329
330			`last_adjusted_timeout = rtems_bsdnet_seconds_since_boot();`
331			`#ifdef DIAGNOSTIC`
332			`log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",`
333			`rtq_reallyold);`
334			`#endif`
335			`arg.found = arg.killed = 0;`
336			`arg.updating = 1;`
337			`s = splnet();`
338			`rnh->rnh_walktree(rnh, in_rtqkill, &arg);`
339			`splx(s);`
340			`}`
341
342			`atv.tv_usec = 0;`
343			`atv.tv_sec = arg.nextstop;`
344			`timeout(in_rtqtimo, rock, hzto(&atv));`
345			`}`
346
347			`void`
348			`in_rtqdrain(void)`
349			`{`
350			`struct radix_node_head *rnh = rt_tables[AF_INET];`
351			`struct rtqk_arg arg;`
352			`int s;`
353			`arg.found = arg.killed = 0;`
354			`arg.rnh = rnh;`
355			`arg.nextstop = 0;`
356			`arg.draining = 1;`
357			`arg.updating = 0;`
358			`s = splnet();`
359			`rnh->rnh_walktree(rnh, in_rtqkill, &arg);`
360			`splx(s);`
361			`}`
362
363			`/*`
364			`* Initialize our routing tree.`
365			`*/`
366			`int`
367			`in_inithead(void **head, int off)`
368			`{`
369			`struct radix_node_head *rnh;`
370
371			`if(!rn_inithead(head, off))`
372			`return 0;`
373
374			`if(head != (void *)&rt_tables[AF_INET]) / BOGUS! */`
375			`return 1; /* only do this for the real routing table */`
376
377			`rnh = *head;`
378			`rnh->rnh_addaddr = in_addroute;`
379			`rnh->rnh_matchaddr = in_matroute;`
380			`rnh->rnh_close = in_clsroute;`
381			`in_rtqtimo(rnh); /* kick off timeout first time */`
382			`return 1;`
383			`}`
384