/*
* 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. 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 8.6 (Berkeley) 10/17/95
*/
/*
* Routines to build and maintain radix trees for routing lookups.
*/
/*
* 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.
*
* 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.
*
* The present version of the code makes use of normal routes in short-
* circuiting an explicit mask and compare operation when testing whether
* a key satisfies a normal route, and also in remembering the unique leaf
* that governs a subtree.
*/
/*
* 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
* or at least learn how many bits match, for normal mask finesse.
*
* It doesn't hurt us to limit how many bytes to check
* to the length of the mask, since if it matches we had a genuine
* match and the leaf we have is the most specific one anyway;
* if it didn't match with a shorter length it would fail
* with a long one. This wins big for class B&C netmasks which
* are probably the most common case...
*/
if (t->rn_mask)
vlen = *(const u_char *)t->rn_mask;
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:
test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
for (b = 7; (test >>= 1) > 0;)
b--;
matched_off = cp - v;
b += matched_off << 3;
rn_b = -1 - b;
/*
* If there is a host route in a duped-key chain, it will be first.
*/
if ((saved_t = t)->rn_mask == 0)
t = t->rn_dupedkey;
for (; t; t = t->rn_dupedkey)
/*
* Even if we don't match exactly as a host,
* we may match if the leaf we wound up at is
* a route to a net.
*/
if (t->rn_flags & RNF_NORMAL) {
if (rn_b <= t->rn_b)
return t;
} else if (rn_satisfies_leaf(v, t, matched_off))
return t;
t = saved_t;
/* start searching up the tree */
do {
struct radix_mask *m;
t = t->rn_p;
m = t->rn_mklist;
if (m) {
/*
* If non-contiguous masks ever become important
* we can restore the masking and open coding of
* the search and satisfaction test and put the
* calculation of "off" back before the "do".
*/
do {
if (m->rm_flags & RNF_NORMAL) {
if (rn_b <= m->rm_b)
return m->rm_leaf;
} else {
off = uimin(t->rn_off, matched_off);
x = rn_search_m(v, t, m->rm_mask);
while (x && x->rn_mask != m->rm_mask)
x = x->rn_dupedkey;
if (x && rn_satisfies_leaf(v, x, off))
return x;
}
m = m->rm_mklist;
} while (m);
}
} while (t != top);
return NULL;
}
if (*mp > *np)
return 1; /* not really, but need to check longer one first */
if (*mp == *np)
for (lim = mp + *mp; mp < lim;)
if (*mp++ > *np++)
return 1;
return 0;
}
/*
* 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 != NULL) {
if ((x = rn_addmask(netmask, 0, top->rn_off)) == NULL)
return NULL;
b_leaf = x->rn_b;
b = -1 - x->rn_b;
netmask = x->rn_key;
}
/*
* Deal with duplicated keys: attach node to previous instance
*/
saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
if (keyduplicated) {
for (t = tt; tt != NULL; t = tt, tt = tt->rn_dupedkey) {
if (tt->rn_mask == netmask)
return NULL;
if (netmask == NULL ||
(tt->rn_mask != NULL &&
(b_leaf < tt->rn_b || /* index(netmask) > node */
rn_refines(netmask, tt->rn_mask) ||
rn_lexobetter(netmask, tt->rn_mask))))
break;
}
/*
* 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.
*
* We also reverse, or doubly link the list through the
* parent pointer.
*/
if (tt == 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;
t->rn_p = tt;
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;
tt->rn_p = t;
if (tt->rn_dupedkey)
tt->rn_dupedkey->rn_p = tt;
}
tt->rn_key = v;
tt->rn_b = -1;
tt->rn_flags = RNF_ACTIVE;
}
/*
* Put mask in tree.
*/
if (netmask != NULL) {
tt->rn_mask = netmask;
tt->rn_b = x->rn_b;
tt->rn_flags |= x->rn_flags & RNF_NORMAL;
}
t = saved_tt->rn_p;
if (keyduplicated)
goto on2;
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) {
for (mp = &t->rn_mklist; x != NULL; x = x->rn_dupedkey) {
if (x->rn_mask != NULL && x->rn_b >= b_leaf &&
x->rn_mklist == NULL) {
*mp = m = rn_new_radix_mask(x, NULL);
if (m != NULL)
mp = &m->rm_mklist;
}
}
} else if (x->rn_mklist != NULL) {
/*
* Skip over masks whose index is > that of new node
*/
for (mp = &x->rn_mklist; (m = *mp) != NULL; mp = &m->rm_mklist)
if (m->rm_b >= b_leaf)
break;
t->rn_mklist = m;
*mp = NULL;
}
on2:
/* Add new route to highest possible ancestor's list */
if (netmask == NULL || 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.
* Need same criteria as when sorting dupedkeys to avoid
* double loop on deletion.
*/
for (mp = &x->rn_mklist; (m = *mp) != NULL; mp = &m->rm_mklist) {
if (m->rm_b < b_leaf)
continue;
if (m->rm_b > b_leaf)
break;
if (m->rm_flags & RNF_NORMAL) {
mmask = m->rm_leaf->rn_mask;
if (tt->rn_flags & RNF_NORMAL) {
log(LOG_ERR, "Non-unique normal route,"
" mask not entered\n");
return tt;
}
} else
mmask = m->rm_mask;
if (mmask == netmask) {
m->rm_refs++;
tt->rn_mklist = m;
return tt;
}
if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask))
break;
}
*mp = rn_new_radix_mask(tt, *mp);
return tt;
}
static struct radix_node *
rn_walknext(struct radix_node *rn, rn_printer_t printer, void *arg)
{
/* If at right child go back up, otherwise, go right */
while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0) {
if (printer != NULL)
(*printer)(arg, SUBTREE_CLOSE);
rn = rn->rn_p;
}
if (printer)
rn_nodeprint(rn->rn_p, printer, arg, "");
/* Find the next *leaf* since next node might vanish, too */
for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;) {
if (printer != NULL)
(*printer)(arg, SUBTREE_OPEN);
rn = rn->rn_l;
}
return rn;
}
static struct radix_node *
rn_walkfirst(struct radix_node *rn, rn_printer_t printer, void *arg)
{
/* First time through node, go left */
while (rn->rn_b >= 0) {
if (printer != NULL)
(*printer)(arg, SUBTREE_OPEN);
rn = rn->rn_l;
}
return rn;
}
int
rn_walktree(
struct radix_node_head *h,
int (*f)(struct radix_node *, void *),
void *w)
{
int error;
struct radix_node *base, *next, *rn;
/*
* 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.
*/
rn = rn_walkfirst(h->rnh_treetop, NULL, NULL);
for (;;) {
base = rn;
next = rn_walknext(rn, NULL, NULL);
/* Process leaves */
while ((rn = base) != NULL) {
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 */
}
struct radix_node *
rn_search_matched(struct radix_node_head *h,
int (*matcher)(struct radix_node *, void *), void *w)
{
bool matched;
struct radix_node *base, *next, *rn;
/*
* 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.
*/
rn = rn_walkfirst(h->rnh_treetop, NULL, NULL);
for (;;) {
base = rn;
next = rn_walknext(rn, NULL, NULL);
/* Process leaves */
while ((rn = base) != NULL) {
base = rn->rn_dupedkey;
if (!(rn->rn_flags & RNF_ROOT)) {
matched = (*matcher)(rn, w);
if (matched)
return rn;
}
}
rn = next;
if (rn->rn_flags & RNF_ROOT)
return NULL;
}
/* NOTREACHED */
}
struct delayinit {
void **head;
int off;
SLIST_ENTRY(delayinit) entries;
};
static SLIST_HEAD(, delayinit) delayinits = SLIST_HEAD_INITIALIZER(delayheads);
static int radix_initialized;
/*
* Initialize a radix tree once radix is initialized. Only for bootstrap.
* Assume that no concurrency protection is necessary at this stage.
*/
void
rn_delayedinit(void **head, int off)
{
struct delayinit *di;
