freebsd-dev/sys/netinet/in_rmx.c
1995-05-30 08:16:23 +00:00

286 lines
7.9 KiB
C

/*
* 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 1.12 1995/03/19 14:29:01 davidg 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/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>
#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;
/*
* For IP, all unicast non-host routes are automatically cloning.
*/
if(!(rt->rt_flags & (RTF_HOST | RTF_CLONING))) {
struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
if(!IN_MULTICAST(ntohl(sin->sin_addr.s_addr))) {
rt->rt_flags |= RTF_PRCLONING;
}
}
return rn_addroute(v_arg, n_arg, head, treenodes);
}
/*
* 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;
}
/* MIB variables: net.inet.ip.{rtexpire,rtmaxcache,rtminexpire}. */
int rtq_reallyold = 60*60; /* one hour is ``really old'' */
int rtq_toomany = 128; /* 128 cached routes is ``too many'' */
int rtq_minreallyold = 10; /* never automatically crank down to less */
/*
* 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 = time.tv_sec + 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 radix_node_head *rnh = ap->rnh;
struct rtentry *rt = (struct rtentry *)rn;
int err;
if(rt->rt_flags & RTPRF_OURS) {
ap->found++;
if(ap->draining || rt->rt_rmx.rmx_expire <= time.tv_sec) {
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
&& (time.tv_sec - rt->rt_rmx.rmx_expire
> rtq_reallyold)) {
rt->rt_rmx.rmx_expire = time.tv_sec
+ 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 */
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.tv_sec + 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.tv_sec - 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.tv_sec;
log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
rtq_reallyold);
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;
}