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BSD 4_3_Net_2 release
[unix-history] / usr / src / sys / net / radix.c
/*
* Copyright (c) 1988, 1989 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 7.9 (Berkeley) 2/4/91
*/
/*
* Routines to build and maintain radix trees for routing lookups.
*/
#ifndef RNF_NORMAL
#include "param.h"
#include "radix.h"
#include "malloc.h"
#define M_DONTWAIT M_NOWAIT
#endif
struct radix_node_head *mask_rnhead;
#define rn_maskhead mask_rnhead->rnh_treetop
struct radix_mask *rn_mkfreelist;
struct radix_node_head *radix_node_head;
#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, head)
struct radix_node *head;
register caddr_t v;
{
register struct radix_node *x;
for (x = head; 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, head, m)
struct radix_node *head;
register caddr_t v, m;
{
register struct radix_node *x;
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;
};
static int gotOddMasks;
static char maskedKey[MAXKEYLEN];
struct radix_node *
rn_match(v, head)
struct radix_node *head;
caddr_t v;
{
register struct radix_node *t = head, *x;
register caddr_t cp = v, cp2, cp3;
caddr_t cplim, mstart;
struct radix_node *saved_t;
int off = t->rn_off, vlen = *(u_char *)cp, matched_off;
/*
* Open code rn_search(v, head) 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 != head);
return 0;
};
#ifdef RN_DEBUG
int rn_nodenum;
struct radix_node *rn_clist;
int rn_saveinfo;
#endif
struct radix_node *
rn_newpair(v, b, nodes)
caddr_t v;
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 = 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;
}
int rn_debug = 1;
struct radix_node *
rn_insert(v, head, dupentry, nodes)
caddr_t v;
struct radix_node *head;
int *dupentry;
struct radix_node nodes[2];
{
int head_off = head->rn_off, vlen = (int)*((u_char *)v);
register struct radix_node *t = rn_search(v, head);
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 = head;
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, 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(netmask, search, skip)
caddr_t netmask;
{
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_maskhead);
mlen = *(u_char *)netmask;
if (Bcmp(netmask, x->rn_key, mlen) == 0)
return (x);
}
R_Malloc(x, struct radix_node *, MAXKEYLEN + 2 * sizeof (*x));
if (x == 0)
return (0);
Bzero(x, MAXKEYLEN + 2 * sizeof (*x));
cp = (caddr_t)(x + 2);
Bcopy(netmask, cp, mlen);
netmask = cp;
x = rn_insert(netmask, rn_maskhead, &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, netmask, head, treenodes)
struct radix_node *head;
caddr_t netmask, v;
struct radix_node treenodes[2];
{
register int j;
register caddr_t cp;
register struct radix_node *t, *x, *tt;
short b = 0, b_leaf;
int vlen = *(u_char *)v, mlen, keyduplicated;
caddr_t cplim; unsigned char *maskp;
struct radix_mask *m, **mp;
struct radix_node *saved_tt;
/*
* 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_maskhead);
mlen = *(u_char *)netmask;
if (Bcmp(netmask, x->rn_key, mlen) != 0) {
x = rn_addmask(netmask, 0, head->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;
} 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.
*
* XXX: we really ought to sort the masks
* for a duplicated key the same way as in a masklist.
* It is an unfortunate pain having to relocate
* the head of the list.
*/
t->rn_dupedkey = tt = treenodes;
#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 != head);
/*
* 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;
}
maskp = (u_char *)m->rm_mask;
for (cp = netmask; cp < cplim; cp++)
if (*(u_char *)cp > *maskp++)
goto on2;
}
on2:
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, netmask, head)
caddr_t v, netmask;
struct radix_node *head;
{
register struct radix_node *t, *p, *x = head;
register struct radix_node *tt = rn_search(v, x);
int b, head_off = x->rn_off, vlen = * (u_char *) v;
struct radix_mask *m, *saved_m, **mp;
struct radix_node *dupedkey, *saved_tt = tt;
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_maskhead)->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 != head);
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 RN_DEBUG
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;
#ifndef RN_DEBUG
x++; t = tt + 1; *x = *t; p = t->rn_p;
#else
x++; b = x->rn_info; t = tt + 1; *x = *t; p = t->rn_p;
x->rn_info = b;
#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;
} else {
for (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");
}
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);
}
char rn_zeros[MAXKEYLEN], rn_ones[MAXKEYLEN];
rn_inithead(head, off, af)
struct radix_node_head **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_af = af;
rnh->rnh_treetop = t;
if (radix_node_head == 0) {
caddr_t cp = rn_ones, cplim = rn_ones + MAXKEYLEN;
while (cp < cplim)
*cp++ = -1;
if (rn_inithead(&radix_node_head, 0, 0) == 0) {
Free(rnh);
*head = 0;
return (0);
}
mask_rnhead = radix_node_head;
}
rnh->rnh_next = radix_node_head->rnh_next;
if (radix_node_head != rnh)
radix_node_head->rnh_next = rnh;
return (1);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.