BSD 4_3_Net_2 release

[unix-history] / usr / src / usr.sbin / named / db_lookup.c

/*
* Copyright (c) 1986 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.
*/

#ifndef lint
static char sccsid[] = "@(#)db_lookup.c 4.18 (Berkeley) 3/21/91";
#endif /* not lint */

/*
* Table lookup routines.
*/

#include <sys/param.h>
#include <arpa/nameser.h>
#include <stdio.h>
#include "db.h"

struct hashbuf *hashtab;        /* root hash table */
struct hashbuf *fcachetab;      /* hash table of cache read from file */

#ifdef DEBUG
extern int debug;
extern FILE *ddt;
#endif

/* 
* Lookup 'name' and return a pointer to the namebuf;
* NULL otherwise. If 'insert', insert name into tables.
* Wildcard lookups are handled.
*/
struct namebuf *
nlookup(name, htpp, fname, insert)
       char *name;
       struct hashbuf **htpp;
       char **fname;
       int insert;
{
       register struct namebuf *np;
       register char *cp;
       register int c;
       register unsigned hval;
       register struct hashbuf *htp;
       struct namebuf *parent = NULL;

       htp = *htpp;
       hval = 0;
       *fname = "???";
       for (cp = name; c = *cp++; ) {
               if (c == '.') {
                       parent = np = nlookup(cp, htpp, fname, insert);
                       if (np == NULL)
                               return (NULL);
                       if (*fname != cp)
                               return (np);
                       if ((htp = np->n_hash) == NULL) {
                               if (!insert) {
                                       if (np->n_dname[0] == '*' && 
                                           np->n_dname[1] == '\0')
                                               *fname = name;
                                       return (np);
                               }
                               htp = savehash((struct hashbuf *)NULL);
                               np->n_hash = htp;
                       }
                       *htpp = htp;
                       break;
               }
               hval <<= HASHSHIFT;
               hval += c & HASHMASK;
       }
       c = *--cp;
       *cp = '\0';
       /*
        * Lookup this label in current hash table.
        */
       for (np = htp->h_tab[hval % htp->h_size]; np != NULL; np = np->n_next) {
               if (np->n_hashval == hval &&
                   strcasecmp(name, np->n_dname) == 0) {
                       *cp = c;
                       *fname = name;
                       return (np);
               }
       }
       if (!insert) {
               /*
                * Look for wildcard in this hash table.
                * Don't use a cached "*" name as a wildcard,
                * only authoritative.
                */
               hval = ('*' & HASHMASK)  % htp->h_size;
               for (np = htp->h_tab[hval]; np != NULL; np = np->n_next) {
                       if (np->n_dname[0] == '*'  && np->n_dname[1] == '\0' &&
                           np->n_data && np->n_data->d_zone != 0) {
                               *cp = c;
                               *fname = name;
                               return (np);
                       }
               }
               *cp = c;
               return (parent);
       }
       np = savename(name);
       np->n_parent = parent;
       np->n_hashval = hval;
       hval %= htp->h_size;
       np->n_next = htp->h_tab[hval];
       htp->h_tab[hval] = np;
       /* increase hash table size */
       if (++htp->h_cnt > htp->h_size * 2) {
               *htpp = savehash(htp);
               if (parent == NULL) {
                       if (htp == hashtab)
                           hashtab = *htpp;
                       else
                           fcachetab = *htpp;
               }
               else
                       parent->n_hash = *htpp;
               htp = *htpp;
       }
       *cp = c;
       *fname = name;
       return (np);
}

/*
* Does the data record match the class and type?
*/
match(dp, class, type)
       register struct databuf *dp;
       register int class, type;
{
#ifdef DEBUG
       if (debug >= 5)
               fprintf(ddt,"match(0x%x, %d, %d) %d, %d\n", dp, class, type,
                       dp->d_class, dp->d_type);
#endif
       if (dp->d_class != class && class != C_ANY)
               return (0);
       if (dp->d_type != type && type != T_ANY)
               return (0);
       return (1);
}