BSD 4.4 Lite Kernel Sources

1 files changed, 757 insertions, 0 deletions

diff --git a/sys/net/radix.c b/sys/net/radix.c
new file mode 100644
index 0000000..f182eb7
--- /dev/null
+++ b/sys/net/radix.c
@@ -0,0 +1,757 @@
+/*
+ * Copyright (c) 1988, 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS 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.
+ *
+ *	@(#)radix.c	8.2 (Berkeley) 1/4/94
+ */
+
+/*
+ * Routines to build and maintain radix trees for routing lookups.
+ */
+#ifndef RNF_NORMAL
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#define	M_DONTWAIT M_NOWAIT
+#ifdef	KERNEL
+#include <sys/domain.h>
+#endif
+#endif
+
+#include <net/radix.h>
+
+int	max_keylen;
+struct radix_mask *rn_mkfreelist;
+struct radix_node_head *mask_rnhead;
+static int gotOddMasks;
+static char *maskedKey;
+static char *rn_zeros, *rn_ones;
+
+#define rn_masktop (mask_rnhead->rnh_treetop)
+#undef Bcmp
+#define Bcmp(a, b, l) (l == 0 ? 0 : bcmp((caddr_t)(a), (caddr_t)(b), (u_long)l))
+/*
+ * The data structure for the keys is a radix tree with one way
+ * branching removed.  The index rn_b at an internal node n represents a bit
+ * position to be tested.  The tree is arranged so that all descendants
+ * of a node n have keys whose bits all agree up to position rn_b - 1.
+ * (We say the index of n is rn_b.)
+ *
+ * There is at least one descendant which has a one bit at position rn_b,
+ * and at least one with a zero there.
+ *
+ * A route is determined by a pair of key and mask.  We require that the
+ * bit-wise logical and of the key and mask to be the key.
+ * We define the index of a route to associated with the mask to be
+ * the first bit number in the mask where 0 occurs (with bit number 0
+ * representing the highest order bit).
+ * 
+ * We say a mask is normal if every bit is 0, past the index of the mask.
+ * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b,
+ * and m is a normal mask, then the route applies to every descendant of n.
+ * If the index(m) < rn_b, this implies the trailing last few bits of k
+ * before bit b are all 0, (and hence consequently true of every descendant
+ * of n), so the route applies to all descendants of the node as well.
+ *
+ * The present version of the code makes no use of normal routes,
+ * but similar logic shows that a non-normal mask m such that
+ * index(m) <= index(n) could potentially apply to many children of n.
+ * Thus, for each non-host route, we attach its mask to a list at an internal
+ * node as high in the tree as we can go. 
+ */
+
+struct radix_node *
+rn_search(v_arg, head)
+	void *v_arg;
+	struct radix_node *head;
+{
+	register struct radix_node *x;
+	register caddr_t v;
+
+	for (x = head, v = v_arg; x->rn_b >= 0;) {
+		if (x->rn_bmask & v[x->rn_off])
+			x = x->rn_r;
+		else
+			x = x->rn_l;
+	}
+	return (x);
+};
+
+struct radix_node *
+rn_search_m(v_arg, head, m_arg)
+	struct radix_node *head;
+	void *v_arg, *m_arg;
+{
+	register struct radix_node *x;
+	register caddr_t v = v_arg, m = m_arg;
+
+	for (x = head; x->rn_b >= 0;) {
+		if ((x->rn_bmask & m[x->rn_off]) &&
+		    (x->rn_bmask & v[x->rn_off]))
+			x = x->rn_r;
+		else
+			x = x->rn_l;
+	}
+	return x;
+};
+
+int
+rn_refines(m_arg, n_arg)
+	void *m_arg, *n_arg;
+{
+	register caddr_t m = m_arg, n = n_arg;
+	register caddr_t lim, lim2 = lim = n + *(u_char *)n;
+	int longer = (*(u_char *)n++) - (int)(*(u_char *)m++);
+	int masks_are_equal = 1;
+
+	if (longer > 0)
+		lim -= longer;
+	while (n < lim) {
+		if (*n & ~(*m))
+			return 0;
+		if (*n++ != *m++)
+			masks_are_equal = 0;
+			
+	}
+	while (n < lim2)
+		if (*n++)
+			return 0;
+	if (masks_are_equal && (longer < 0))
+		for (lim2 = m - longer; m < lim2; )
+			if (*m++)
+				return 1;
+	return (!masks_are_equal);
+}
+
+
+struct radix_node *
+rn_match(v_arg, head)
+	void *v_arg;
+	struct radix_node_head *head;
+{
+	caddr_t v = v_arg;
+	register struct radix_node *t = head->rnh_treetop, *x;
+	register caddr_t cp = v, cp2, cp3;
+	caddr_t cplim, mstart;
+	struct radix_node *saved_t, *top = t;
+	int off = t->rn_off, vlen = *(u_char *)cp, matched_off;
+
+	/*
+	 * Open code rn_search(v, top) to avoid overhead of extra
+	 * subroutine call.
+	 */
+	for (; t->rn_b >= 0; ) {
+		if (t->rn_bmask & cp[t->rn_off])
+			t = t->rn_r;
+		else
+			t = t->rn_l;
+	}
+	/*
+	 * See if we match exactly as a host destination
+	 */
+	cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
+	for (; cp < cplim; cp++, cp2++)
+		if (*cp != *cp2)
+			goto on1;
+	/*
+	 * This extra grot is in case we are explicitly asked
+	 * to look up the default.  Ugh!
+	 */
+	if ((t->rn_flags & RNF_ROOT) && t->rn_dupedkey)
+		t = t->rn_dupedkey;
+	return t;
+on1:
+	matched_off = cp - v;
+	saved_t = t;
+	do {
+	    if (t->rn_mask) {
+		/*
+		 * Even if we don't match exactly as a hosts;
+		 * we may match if the leaf we wound up at is
+		 * a route to a net.
+		 */
+		cp3 = matched_off + t->rn_mask;
+		cp2 = matched_off + t->rn_key;
+		for (; cp < cplim; cp++)
+			if ((*cp2++ ^ *cp) & *cp3++)
+				break;
+		if (cp == cplim)
+			return t;
+		cp = matched_off + v;
+	    }
+	} while (t = t->rn_dupedkey);
+	t = saved_t;
+	/* start searching up the tree */
+	do {
+		register struct radix_mask *m;
+		t = t->rn_p;
+		if (m = t->rn_mklist) {
+			/*
+			 * After doing measurements here, it may
+			 * turn out to be faster to open code
+			 * rn_search_m here instead of always
+			 * copying and masking.
+			 */
+			off = min(t->rn_off, matched_off);
+			mstart = maskedKey + off;
+			do {
+				cp2 = mstart;
+				cp3 = m->rm_mask + off;
+				for (cp = v + off; cp < cplim;)
+					*cp2++ =  *cp++ & *cp3++;
+				x = rn_search(maskedKey, t);
+				while (x && x->rn_mask != m->rm_mask)
+					x = x->rn_dupedkey;
+				if (x &&
+				    (Bcmp(mstart, x->rn_key + off,
+					vlen - off) == 0))
+					    return x;
+			} while (m = m->rm_mklist);
+		}
+	} while (t != top);
+	return 0;
+};
+		
+#ifdef RN_DEBUG
+int	rn_nodenum;
+struct	radix_node *rn_clist;
+int	rn_saveinfo;
+int	rn_debug =  1;
+#endif
+
+struct radix_node *
+rn_newpair(v, b, nodes)
+	void *v;
+	int b;
+	struct radix_node nodes[2];
+{
+	register struct radix_node *tt = nodes, *t = tt + 1;
+	t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7);
+	t->rn_l = tt; t->rn_off = b >> 3;
+	tt->rn_b = -1; tt->rn_key = (caddr_t)v; tt->rn_p = t;
+	tt->rn_flags = t->rn_flags = RNF_ACTIVE;
+#ifdef RN_DEBUG
+	tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
+	tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
+#endif
+	return t;
+}
+
+struct radix_node *
+rn_insert(v_arg, head, dupentry, nodes)
+	void *v_arg;
+	struct radix_node_head *head;
+	int *dupentry;
+	struct radix_node nodes[2];
+{
+	caddr_t v = v_arg;
+	struct radix_node *top = head->rnh_treetop;
+	int head_off = top->rn_off, vlen = (int)*((u_char *)v);
+	register struct radix_node *t = rn_search(v_arg, top);
+	register caddr_t cp = v + head_off;
+	register int b;
+	struct radix_node *tt;
+    	/*
+	 *find first bit at which v and t->rn_key differ
+	 */
+    {
+	register caddr_t cp2 = t->rn_key + head_off;
+	register int cmp_res;
+	caddr_t cplim = v + vlen;
+
+	while (cp < cplim)
+		if (*cp2++ != *cp++)
+			goto on1;
+	*dupentry = 1;
+	return t;
+on1:
+	*dupentry = 0;
+	cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
+	for (b = (cp - v) << 3; cmp_res; b--)
+		cmp_res >>= 1;
+    }
+    {
+	register struct radix_node *p, *x = top;
+	cp = v;
+	do {
+		p = x;
+		if (cp[x->rn_off] & x->rn_bmask) 
+			x = x->rn_r;
+		else x = x->rn_l;
+	} while (b > (unsigned) x->rn_b); /* x->rn_b < b && x->rn_b >= 0 */
+#ifdef RN_DEBUG
+	if (rn_debug)
+		printf("Going In:\n"), traverse(p);
+#endif
+	t = rn_newpair(v_arg, b, nodes); tt = t->rn_l;
+	if ((cp[p->rn_off] & p->rn_bmask) == 0)
+		p->rn_l = t;
+	else
+		p->rn_r = t;
+	x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */
+	if ((cp[t->rn_off] & t->rn_bmask) == 0) {
+		t->rn_r = x;
+	} else {
+		t->rn_r = tt; t->rn_l = x;
+	}
+#ifdef RN_DEBUG
+	if (rn_debug)
+		printf("Coming out:\n"), traverse(p);
+#endif
+    }
+	return (tt);
+}
+
+struct radix_node *
+rn_addmask(n_arg, search, skip)
+	int search, skip;
+	void *n_arg;
+{
+	caddr_t netmask = (caddr_t)n_arg;
+	register struct radix_node *x;
+	register caddr_t cp, cplim;
+	register int b, mlen, j;
+	int maskduplicated;
+
+	mlen = *(u_char *)netmask;
+	if (search) {
+		x = rn_search(netmask, rn_masktop);
+		mlen = *(u_char *)netmask;
+		if (Bcmp(netmask, x->rn_key, mlen) == 0)
+			return (x);
+	}
+	R_Malloc(x, struct radix_node *, max_keylen + 2 * sizeof (*x));
+	if (x == 0)
+		return (0);
+	Bzero(x, max_keylen + 2 * sizeof (*x));
+	cp = (caddr_t)(x + 2);
+	Bcopy(netmask, cp, mlen);
+	netmask = cp;
+	x = rn_insert(netmask, mask_rnhead, &maskduplicated, x);
+	/*
+	 * Calculate index of mask.
+	 */
+	cplim = netmask + mlen;
+	for (cp = netmask + skip; cp < cplim; cp++)
+		if (*(u_char *)cp != 0xff)
+			break;
+	b = (cp - netmask) << 3;
+	if (cp != cplim) {
+		if (*cp != 0) {
+			gotOddMasks = 1;
+			for (j = 0x80; j; b++, j >>= 1)  
+				if ((j & *cp) == 0)
+					break;
+		}
+	}
+	x->rn_b = -1 - b;
+	return (x);
+}
+
+struct radix_node *
+rn_addroute(v_arg, n_arg, head, treenodes)
+	void *v_arg, *n_arg;
+	struct radix_node_head *head;
+	struct radix_node treenodes[2];
+{
+	caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
+	register struct radix_node *t, *x, *tt;
+	struct radix_node *saved_tt, *top = head->rnh_treetop;
+	short b = 0, b_leaf;
+	int mlen, keyduplicated;
+	caddr_t cplim;
+	struct radix_mask *m, **mp;
+
+	/*
+	 * In dealing with non-contiguous masks, there may be
+	 * many different routes which have the same mask.
+	 * We will find it useful to have a unique pointer to
+	 * the mask to speed avoiding duplicate references at
+	 * nodes and possibly save time in calculating indices.
+	 */
+	if (netmask)  {
+		x = rn_search(netmask, rn_masktop);
+		mlen = *(u_char *)netmask;
+		if (Bcmp(netmask, x->rn_key, mlen) != 0) {
+			x = rn_addmask(netmask, 0, top->rn_off);
+			if (x == 0)
+				return (0);
+		}
+		netmask = x->rn_key;
+		b = -1 - x->rn_b;
+	}
+	/*
+	 * Deal with duplicated keys: attach node to previous instance
+	 */
+	saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
+	if (keyduplicated) {
+		do {
+			if (tt->rn_mask == netmask)
+				return (0);
+			t = tt;
+			if (netmask == 0 ||
+			    (tt->rn_mask && rn_refines(netmask, tt->rn_mask)))
+				break;
+		} while (tt = tt->rn_dupedkey);
+		/*
+		 * If the mask is not duplicated, we wouldn't
+		 * find it among possible duplicate key entries
+		 * anyway, so the above test doesn't hurt.
+		 *
+		 * We sort the masks for a duplicated key the same way as
+		 * in a masklist -- most specific to least specific.
+		 * This may require the unfortunate nuisance of relocating
+		 * the head of the list.
+		 */
+		if (tt && t == saved_tt) {
+			struct	radix_node *xx = x;
+			/* link in at head of list */
+			(tt = treenodes)->rn_dupedkey = t;
+			tt->rn_flags = t->rn_flags;
+			tt->rn_p = x = t->rn_p;
+			if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt;
+			saved_tt = tt; x = xx;
+		} else {
+			(tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
+			t->rn_dupedkey = tt;
+		}
+#ifdef RN_DEBUG
+		t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
+		tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
+#endif
+		t = saved_tt;
+		tt->rn_key = (caddr_t) v;
+		tt->rn_b = -1;
+		tt->rn_flags = t->rn_flags & ~RNF_ROOT;
+	}
+	/*
+	 * Put mask in tree.
+	 */
+	if (netmask) {
+		tt->rn_mask = netmask;
+		tt->rn_b = x->rn_b;
+	}
+	t = saved_tt->rn_p;
+	b_leaf = -1 - t->rn_b;
+	if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r;
+	/* Promote general routes from below */
+	if (x->rn_b < 0) { 
+		if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) {
+			MKGet(m);
+			if (m) {
+				Bzero(m, sizeof *m);
+				m->rm_b = x->rn_b;
+				m->rm_mask = x->rn_mask;
+				x->rn_mklist = t->rn_mklist = m;
+			}
+		}
+	} else if (x->rn_mklist) {
+		/*
+		 * Skip over masks whose index is > that of new node
+		 */
+		for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist)
+			if (m->rm_b >= b_leaf)
+				break;
+		t->rn_mklist = m; *mp = 0;
+	}
+	/* Add new route to highest possible ancestor's list */
+	if ((netmask == 0) || (b > t->rn_b ))
+		return tt; /* can't lift at all */
+	b_leaf = tt->rn_b;
+	do {
+		x = t;
+		t = t->rn_p;
+	} while (b <= t->rn_b && x != top);
+	/*
+	 * Search through routes associated with node to
+	 * insert new route according to index.
+	 * For nodes of equal index, place more specific
+	 * masks first.
+	 */
+	cplim = netmask + mlen;
+	for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) {
+		if (m->rm_b < b_leaf)
+			continue;
+		if (m->rm_b > b_leaf)
+			break;
+		if (m->rm_mask == netmask) {
+			m->rm_refs++;
+			tt->rn_mklist = m;
+			return tt;
+		}
+		if (rn_refines(netmask, m->rm_mask))
+			break;
+	}
+	MKGet(m);
+	if (m == 0) {
+		printf("Mask for route not entered\n");
+		return (tt);
+	}
+	Bzero(m, sizeof *m);
+	m->rm_b = b_leaf;
+	m->rm_mask = netmask;
+	m->rm_mklist = *mp;
+	*mp = m;
+	tt->rn_mklist = m;
+	return tt;
+}
+
+struct radix_node *
+rn_delete(v_arg, netmask_arg, head)
+	void *v_arg, *netmask_arg;
+	struct radix_node_head *head;
+{
+	register struct radix_node *t, *p, *x, *tt;
+	struct radix_mask *m, *saved_m, **mp;
+	struct radix_node *dupedkey, *saved_tt, *top;
+	caddr_t v, netmask;
+	int b, head_off, vlen;
+
+	v = v_arg;
+	netmask = netmask_arg;
+	x = head->rnh_treetop;
+	tt = rn_search(v, x);
+	head_off = x->rn_off;
+	vlen =  *(u_char *)v;
+	saved_tt = tt;
+	top = x;
+	if (tt == 0 ||
+	    Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
+		return (0);
+	/*
+	 * Delete our route from mask lists.
+	 */
+	if (dupedkey = tt->rn_dupedkey) {
+		if (netmask) 
+			netmask = rn_search(netmask, rn_masktop)->rn_key;
+		while (tt->rn_mask != netmask)
+			if ((tt = tt->rn_dupedkey) == 0)
+				return (0);
+	}
+	if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0)
+		goto on1;
+	if (m->rm_mask != tt->rn_mask) {
+		printf("rn_delete: inconsistent annotation\n");
+		goto on1;
+	}
+	if (--m->rm_refs >= 0)
+		goto on1;
+	b = -1 - tt->rn_b;
+	t = saved_tt->rn_p;
+	if (b > t->rn_b)
+		goto on1; /* Wasn't lifted at all */
+	do {
+		x = t;
+		t = t->rn_p;
+	} while (b <= t->rn_b && x != top);
+	for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist)
+		if (m == saved_m) {
+			*mp = m->rm_mklist;
+			MKFree(m);
+			break;
+		}
+	if (m == 0)
+		printf("rn_delete: couldn't find our annotation\n");
+on1:
+	/*
+	 * Eliminate us from tree
+	 */
+	if (tt->rn_flags & RNF_ROOT)
+		return (0);
+#ifdef RN_DEBUG
+	/* Get us out of the creation list */
+	for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {}
+	if (t) t->rn_ybro = tt->rn_ybro;
+#endif
+	t = tt->rn_p;
+	if (dupedkey) {
+		if (tt == saved_tt) {
+			x = dupedkey; x->rn_p = t;
+			if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x;
+		} else {
+			for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
+				p = p->rn_dupedkey;
+			if (p) p->rn_dupedkey = tt->rn_dupedkey;
+			else printf("rn_delete: couldn't find us\n");
+		}
+		t = tt + 1;
+		if  (t->rn_flags & RNF_ACTIVE) {
+#ifndef RN_DEBUG
+			*++x = *t; p = t->rn_p;
+#else
+			b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p;
+#endif
+			if (p->rn_l == t) p->rn_l = x; else p->rn_r = x;
+			x->rn_l->rn_p = x; x->rn_r->rn_p = x;
+		}
+		goto out;
+	}
+	if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l;
+	p = t->rn_p;
+	if (p->rn_r == t) p->rn_r = x; else p->rn_l = x;
+	x->rn_p = p;
+	/*
+	 * Demote routes attached to us.
+	 */
+	if (t->rn_mklist) {
+		if (x->rn_b >= 0) {
+			for (mp = &x->rn_mklist; m = *mp;)
+				mp = &m->rm_mklist;
+			*mp = t->rn_mklist;
+		} else {
+			for (m = t->rn_mklist; m;) {
+				struct radix_mask *mm = m->rm_mklist;
+				if (m == x->rn_mklist && (--(m->rm_refs) < 0)) {
+					x->rn_mklist = 0;
+					MKFree(m);
+				} else 
+					printf("%s %x at %x\n",
+					    "rn_delete: Orphaned Mask", m, x);
+				m = mm;
+			}
+		}
+	}
+	/*
+	 * We may be holding an active internal node in the tree.
+	 */
+	x = tt + 1;
+	if (t != x) {
+#ifndef RN_DEBUG
+		*t = *x;
+#else
+		b = t->rn_info; *t = *x; t->rn_info = b;
+#endif
+		t->rn_l->rn_p = t; t->rn_r->rn_p = t;
+		p = x->rn_p;
+		if (p->rn_l == x) p->rn_l = t; else p->rn_r = t;
+	}
+out:
+	tt->rn_flags &= ~RNF_ACTIVE;
+	tt[1].rn_flags &= ~RNF_ACTIVE;
+	return (tt);
+}
+
+int
+rn_walktree(h, f, w)
+	struct radix_node_head *h;
+	register int (*f)();
+	void *w;
+{
+	int error;
+	struct radix_node *base, *next;
+	register struct radix_node *rn = h->rnh_treetop;
+	/*
+	 * This gets complicated because we may delete the node
+	 * while applying the function f to it, so we need to calculate
+	 * the successor node in advance.
+	 */
+	/* First time through node, go left */
+	while (rn->rn_b >= 0)
+		rn = rn->rn_l;
+	for (;;) {
+		base = rn;
+		/* If at right child go back up, otherwise, go right */
+		while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0)
+			rn = rn->rn_p;
+		/* Find the next *leaf* since next node might vanish, too */
+		for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;)
+			rn = rn->rn_l;
+		next = rn;
+		/* Process leaves */
+		while (rn = base) {
+			base = rn->rn_dupedkey;
+			if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w)))
+				return (error);
+		}
+		rn = next;
+		if (rn->rn_flags & RNF_ROOT)
+			return (0);
+	}
+	/* NOTREACHED */
+}
+
+int
+rn_inithead(head, off)
+	void **head;
+	int off;
+{
+	register struct radix_node_head *rnh;
+	register struct radix_node *t, *tt, *ttt;
+	if (*head)
+		return (1);
+	R_Malloc(rnh, struct radix_node_head *, sizeof (*rnh));
+	if (rnh == 0)
+		return (0);
+	Bzero(rnh, sizeof (*rnh));
+	*head = rnh;
+	t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
+	ttt = rnh->rnh_nodes + 2;
+	t->rn_r = ttt;
+	t->rn_p = t;
+	tt = t->rn_l;
+	tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
+	tt->rn_b = -1 - off;
+	*ttt = *tt;
+	ttt->rn_key = rn_ones;
+	rnh->rnh_addaddr = rn_addroute;
+	rnh->rnh_deladdr = rn_delete;
+	rnh->rnh_matchaddr = rn_match;
+	rnh->rnh_walktree = rn_walktree;
+	rnh->rnh_treetop = t;
+	return (1);
+}
+
+void
+rn_init()
+{
+	char *cp, *cplim;
+#ifdef KERNEL
+	struct domain *dom;
+
+	for (dom = domains; dom; dom = dom->dom_next)
+		if (dom->dom_maxrtkey > max_keylen)
+			max_keylen = dom->dom_maxrtkey;
+#endif
+	if (max_keylen == 0) {
+		printf("rn_init: radix functions require max_keylen be set\n");
+		return;
+	}
+	R_Malloc(rn_zeros, char *, 3 * max_keylen);
+	if (rn_zeros == NULL)
+		panic("rn_init");
+	Bzero(rn_zeros, 3 * max_keylen);
+	rn_ones = cp = rn_zeros + max_keylen;
+	maskedKey = cplim = rn_ones + max_keylen;
+	while (cp < cplim)
+		*cp++ = -1;
+	if (rn_inithead((void **)&mask_rnhead, 0) == 0)
+		panic("rn_init 2");
+}