in6_rmx.c

嵌入式操作系统ECOS的网络开发包

 */
static struct radix_node *
in6_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'' */
static int rtq_minreallyold = 10;
	/* never automatically crank down to less */
static int rtq_toomany = 128;
	/* 128 cached routes is ``too many'' */

/*
 * On last reference drop, mark the route as belong to us so that it can be
 * timed out.
 */
static void
in6_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_second + 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 mode;
	int updating;
	int draining;
	int killed;
	int found;
	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
in6_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 <= time_second) {
			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, "in6_rtqkill: error %d", 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
in6_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, in6_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, "in6_rtqtimo: adjusted rtq_reallyold to %d",
		    rtq_reallyold);
#endif
		arg.found = arg.killed = 0;
		arg.updating = 1;
		s = splnet();
		rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
		splx(s);
	}

	atv.tv_usec = 0;
	atv.tv_sec = arg.nextstop;
	timeout(in6_rtqtimo, rock, tvtohz(&atv));
}

/*
 * Age old PMTUs.
 */
struct mtuex_arg {
	struct radix_node_head *rnh;
	time_t nextstop;
};

static int
in6_mtuexpire(struct radix_node *rn, void *rock)
{
	struct rtentry *rt = (struct rtentry *)rn;
	struct mtuex_arg *ap = rock;

	/* sanity */
	if (!rt)
		panic("rt == NULL in in6_mtuexpire");

	if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) {
		if (rt->rt_rmx.rmx_expire <= time_second) {
			rt->rt_flags |= RTF_PROBEMTU;
		} else {
			ap->nextstop = lmin(ap->nextstop,
					rt->rt_rmx.rmx_expire);
		}
	}

	return 0;
}

#define	MTUTIMO_DEFAULT	(60*1)

static void
in6_mtutimo(void *rock)
{
	struct radix_node_head *rnh = rock;
	struct mtuex_arg arg;
	struct timeval atv;
	int s;

	arg.rnh = rnh;
	arg.nextstop = time_second + MTUTIMO_DEFAULT;
	s = splnet();
	rnh->rnh_walktree(rnh, in6_mtuexpire, &arg);
	splx(s);

	atv.tv_usec = 0;
	atv.tv_sec = arg.nextstop;
	if (atv.tv_sec < time_second) {
		printf("invalid mtu expiration time on routing table\n");
		arg.nextstop = time_second + 30;	/* last resort */
	}
	timeout(in6_mtutimo, rock, tvtohz(&atv));
}

#if 0
void
in6_rtqdrain()
{
	struct radix_node_head *rnh = rt_tables[AF_INET6];
	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, in6_rtqkill, &arg);
	splx(s);
}
#endif

/*
 * Initialize our routing tree.
 */
int
in6_inithead(void **head, int off)
{
	struct radix_node_head *rnh;

	if (!rn_inithead(head, off))
		return 0;

	if (head != (void **)&rt_tables[AF_INET6]) /* BOGUS! */
		return 1;	/* only do this for the real routing table */

	rnh = *head;
	rnh->rnh_addaddr = in6_addroute;
	rnh->rnh_matchaddr = in6_matroute;
	rnh->rnh_close = in6_clsroute;
	in6_rtqtimo(rnh);	/* kick off timeout first time */
	in6_mtutimo(rnh);	/* kick off timeout first time */
	return 1;
}