[unix-history] / usr.sbin / named / db_update.c

/*
 * Copyright (c) 1986, 1990 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_update.c	4.28 (Berkeley) 3/21/91";
#endif /* not lint */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <stdio.h>
#include <syslog.h>
#include "ns.h"
#include "db.h"

extern struct timeval	tt;
extern FILE *ddt;
extern struct sockaddr_in from_addr;	/* Source addr of last packet */
extern int needs_prime_cache;

int	max_cache_ttl = (7*24*60*60);	/* ONE_WEEK maximum ttl */
int	min_cache_ttl = (5*60);		/* 5 minute minimum ttl */

/*
 * Update data base. Flags control the action.
 * Inverse query tables modified.
 */
db_update(name, odp, newdp, flags, htp)
	char name[];
	struct databuf *odp, *newdp;
	int flags;
	struct hashbuf *htp;
{
	register struct namebuf *np;
	register struct databuf *dp, *pdp;
	char *fname;
        int foundRR = 0;

#ifdef DEBUG
	if (debug >= 3)
		fprintf(ddt,"db_update(%s, 0x%x, 0x%x, 0%o, 0x%x)%s\n",
		    name, odp, newdp, flags, htp,
		    (odp && (odp->d_flags&DB_F_HINT)) ? " hint":"" );
#endif
	np = nlookup(name, &htp, &fname, newdp != NULL);
	if (np == NULL || fname != name)
		return (NONAME);

        /* Reflect certain updates in hint cache also... */
	/* Don't stick data we are authoritative for in hints. */
        if (!(flags & DB_NOHINTS) && (odp != NULL) &&
	    (odp->d_zone <= 0) && !(odp->d_flags & DB_F_HINT) &&
            ((name[0] == '\0' && odp->d_type == T_NS) ||
	     (odp->d_type == T_A)))
        {
		register struct databuf *dp;
#ifdef DEBUG
		if (debug >= 3)
			fprintf(ddt,"db_update: hint '%s' %d\n",
				name, odp->d_ttl);
#endif
		dp = savedata(odp->d_class, odp->d_type, odp->d_ttl,
			odp->d_data, odp->d_size);
		dp->d_zone = DB_Z_CACHE;
		dp->d_flags = DB_F_HINT;
		if (db_update(name, dp,dp, (flags|DB_NOHINTS), fcachetab) != OK) {
#ifdef DEBUG		
			if (debug > 2)
				fprintf(ddt, "db_update: hint %x freed\n", dp);
#endif
			(void) free((char *)dp);
		}
        }

	if (odp != NULL) {
		pdp = NULL;
		for (dp = np->n_data; dp != NULL; ) {
			if (!match(dp, odp->d_class, odp->d_type)) {
				if ((dp->d_type == T_CNAME ||
				    odp->d_type == T_CNAME) &&
				    odp->d_mark == dp->d_mark &&
				    zones[odp->d_zone].z_type != Z_CACHE) {
					syslog(LOG_ERR,
				"%s has CNAME and other data (illegal)\n",
					    name);
#ifdef DEBUG
					if (debug)
					    fprintf(ddt,
				"db_update: %s: CNAME and more (%d, %d)\n",
						name, odp->d_type, dp->d_type);
#endif
				}
				goto skip;
			}
#ifdef DEBUG
			if (debug >= 5)
				fprintf(ddt,"db_update: flags = %#x, sizes = %d, %d (%d)\n",
				    flags, odp->d_size, dp->d_size,
				    db_cmp(dp, odp));
#endif
			if (flags & DB_NOTAUTH && dp->d_zone) {
#ifdef DEBUG
				if (debug)
					fprintf(ddt,
					"%s attempted update to auth zone %d '%s'\n",
				    inet_ntoa(from_addr.sin_addr),
				    dp->d_zone, zones[dp->d_zone].z_origin);
#endif
				return (AUTH);
			}
			if ((flags & DB_NODATA) && !db_cmp(dp, odp)) {
				/* refresh ttl if cache entry */
				if (dp->d_zone == 0) {
					if (odp->d_zone != 0) {	/* XXX */
						/* changing cache->auth */
						dp->d_zone = odp->d_zone;
						dp->d_ttl = odp->d_ttl;
#ifdef DEBUG
						if (debug > 3)
							fprintf(ddt,
				"db_update: cache entry now in auth zone\n");
#endif
						return (DATAEXISTS);
					}
					fixttl(odp);
					if (odp->d_ttl > dp->d_ttl)
						dp->d_ttl = odp->d_ttl;
#ifdef DEBUG
				        if (debug >= 3)
				        fprintf(ddt,"db_update: new ttl %d, +%d\n",
				                dp->d_ttl, dp->d_ttl - tt.tv_sec);
#endif
				}
				return (DATAEXISTS);
			}
			/*
			 * If the old databuf has some data, check that the
			 * data matches that in the new databuf (so UPDATED
			 * will delete only the matching RR)
			 */
			if (odp->d_size > 0) {
				if (db_cmp(dp, odp))
					goto skip;
			}
			foundRR = 1;
			if (flags & DB_DELETE)
				dp = rm_datum(dp, np, pdp);
			else {
skip:				pdp = dp;
				dp = dp->d_next;
			}
		}
                if (!foundRR) {
			if (flags & DB_DELETE)
				return(NODATA);
			if (flags & DB_MEXIST)
				return(NODATA);
		}
	}
	if (newdp == NULL)
		return (OK);
	fixttl(newdp);
#ifdef DEBUG
        if (debug >= 3)
	        fprintf(ddt,"db_update: adding%s %x\n",
			(newdp->d_flags&DB_F_HINT) ? " hint":"", newdp);
#endif
	if (!(newdp->d_flags & DB_F_HINT))
		addinv(np, newdp);	/* modify inverse query tables */

	/* Add to end of list, generally preserving order */
	newdp->d_next = NULL;
	if ((dp = np->n_data) == NULL)  {
		np->n_data = newdp;
		return (OK);
	}
	/* XXX: need to check for duplicate WKS records and flag error */
	while (dp->d_next != NULL) {
		if ((flags & DB_NODATA) && !db_cmp(dp, newdp))
			return (DATAEXISTS);
		dp = dp->d_next;
	}
	if ((flags & DB_NODATA) && !db_cmp(dp, newdp))
		return (DATAEXISTS);
	dp->d_next = newdp;
	return (OK);
}

fixttl(dp)
register struct databuf *dp;
{
	if (dp->d_zone == 0 && !(dp->d_flags & DB_F_HINT)) {
		if (dp->d_ttl <= tt.tv_sec)
			return;
		else if (dp->d_ttl < tt.tv_sec+min_cache_ttl)
			dp->d_ttl = tt.tv_sec+min_cache_ttl;
		else if (dp->d_ttl > tt.tv_sec+max_cache_ttl)
			dp->d_ttl = tt.tv_sec+max_cache_ttl;
	}
	return;
}

struct invbuf *invtab[INVHASHSZ];	/* Inverse query hash table */

/*
 * Add data 'dp' to inverse query tables for name 'np'.
 */
addinv(np, dp)
	struct namebuf *np;
	struct databuf *dp;
{
	register struct invbuf *ip;
	register int hval, i;

	switch (dp->d_type) {
	case T_A:
	case T_UID:
	case T_GID:
		break;

	default:
		return;
	}

	hval = dhash(dp->d_data, dp->d_size);
	for (ip = invtab[hval]; ip != NULL; ip = ip->i_next)
		for (i = 0; i < INVBLKSZ; i++)
			if (ip->i_dname[i] == NULL) {
				ip->i_dname[i] = np;
				return;
			}
	ip = saveinv();
	ip->i_next = invtab[hval];
	invtab[hval] = ip;
	ip->i_dname[0] = np;
}

/*
 * Remove data 'odp' from inverse query table.
 */
rminv(odp)
	struct databuf *odp;
{
	register struct invbuf *ip;
	register struct databuf *dp;
	struct namebuf *np;
	register int i;

	for (ip = invtab[dhash(odp->d_data, odp->d_size)]; ip != NULL;
	    ip = ip->i_next) {
		for (i = 0; i < INVBLKSZ; i++) {
			if ((np = ip->i_dname[i]) == NULL)
				break;
			for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
				if (!match(dp, odp->d_class, odp->d_type))
					continue;
				if (db_cmp(dp, odp))
					continue;
				while (i < INVBLKSZ-1) {
					ip->i_dname[i] = ip->i_dname[i+1];
					i++;
				}
				ip->i_dname[i] = NULL;
				return;
			}
		}
	}
}

/*
 * Compute hash value from data.
 */
dhash(dp, dlen)
	char *dp;
	int dlen;
{
	register char *cp;
	register unsigned hval;
	register int n;

	n = dlen;
	if (n > 8)
		n = 8;
	hval = 0;
	for (cp = dp; --n >= 0; ) {
		hval <<= 1;
		hval += *cp++;
	}
	return (hval % INVHASHSZ);
}

/*
 * Compare type, class and data from databufs for equivalence.
 * Must be case insensitive for some domain names.
 * Return 0 if equivalent, nonzero otherwise.
 */
db_cmp(dp1, dp2)
	register struct databuf *dp1, *dp2;

{
	register char *cp1, *cp2;
	int len;

	if (dp1->d_type != dp2->d_type || dp1->d_class != dp2->d_class)
		return(1);
	if (dp1->d_size != dp2->d_size)
		return(1);
	if (dp1->d_mark != dp2->d_mark)
		return(1);		/* old and new RR's are distinct */
	switch (dp1->d_type) {

	case T_A:
	case T_UID:
	case T_GID:
	case T_WKS:
	case T_NULL:
#ifdef ALLOW_T_UNSPEC
        case T_UNSPEC:
#endif ALLOW_T_UNSPEC
		return(bcmp(dp1->d_data, dp2->d_data, dp1->d_size));

	case T_NS:
	case T_CNAME:
	case T_PTR:
	case T_MB:
	case T_MG:
	case T_MR:
	case T_UINFO:
		return(strcasecmp(dp1->d_data, dp2->d_data));

	case T_HINFO:
		cp1 = dp1->d_data;
		cp2 = dp2->d_data;
		len = *cp1;
		if (strncasecmp(++cp1, ++cp2, len))
			return(1);
		cp1 += len;
		cp2 += len;
		len = *cp1;
		return(strncasecmp(++cp1, ++cp2, len));

	case T_SOA:
	case T_MINFO:
		if (strcasecmp(dp1->d_data, dp2->d_data))
			return(1);
		cp1 = dp1->d_data + strlen(dp1->d_data) + 1;
		cp2 = dp2->d_data + strlen(dp2->d_data) + 1;
		if (dp1->d_type != T_SOA)
			return(strcasecmp(cp1, cp2));
		if (strcasecmp(cp1, cp2))
			return(1);
		cp1 += strlen(cp1) + 1;
		cp2 += strlen(cp2) + 1;
		return(bcmp(cp1, cp2, sizeof(u_long) * 5));
	
	case T_MX:
		cp1 = dp1->d_data;
		cp2 = dp2->d_data;
		if (*cp1++ != *cp2++ || *cp1++ != *cp2++)	/* cmp prio */
			return(1);
		return(strcasecmp(cp1, cp2));

	case T_TXT:
		if (dp1->d_size != dp2->d_size)
			return(1);
		return(bcmp(dp1->d_data, dp2->d_data, dp1->d_size));

	default:
		return (1);
	}
}
Commit	Line	Data
15637ed4 RG	1	/*
	2	* Copyright (c) 1986, 1990 Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	* 3. All advertising materials mentioning features or use of this software
	14	* must display the following acknowledgement:
	15	* This product includes software developed by the University of
	16	* California, Berkeley and its contributors.
	17	* 4. Neither the name of the University nor the names of its contributors
	18	* may be used to endorse or promote products derived from this software
	19	* without specific prior written permission.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	22	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	23	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	24	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	25	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	26	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	27	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	28	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	29	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	30	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	31	* SUCH DAMAGE.
	32	*/
	33
	34	#ifndef lint
	35	static char sccsid[] = "@(#)db_update.c 4.28 (Berkeley) 3/21/91";
	36	#endif /* not lint */
	37
	38	#include <sys/param.h>
	39	#include <sys/socket.h>
	40	#include <sys/time.h>
	41	#include <netinet/in.h>
	42	#include <arpa/nameser.h>
	43	#include <stdio.h>
	44	#include <syslog.h>
	45	#include "ns.h"
	46	#include "db.h"
	47
	48	extern struct timeval tt;
	49	extern FILE *ddt;
	50	extern struct sockaddr_in from_addr; /* Source addr of last packet */
	51	extern int needs_prime_cache;
	52
	53	int max_cache_ttl = (7246060); / ONE_WEEK maximum ttl */
	54	int min_cache_ttl = (560); / 5 minute minimum ttl */
	55
	56	/*
	57	* Update data base. Flags control the action.
	58	* Inverse query tables modified.
	59	*/
	60	db_update(name, odp, newdp, flags, htp)
	61	char name[];
	62	struct databuf odp, newdp;
	63	int flags;
	64	struct hashbuf *htp;
65	{
66	register struct namebuf *np;
67	register struct databuf dp, pdp;
68	char *fname;
69	int foundRR = 0;
70
71	#ifdef DEBUG
72	if (debug >= 3)
73	fprintf(ddt,"db_update(%s, 0x%x, 0x%x, 0%o, 0x%x)%s\n",
74	name, odp, newdp, flags, htp,
75	(odp && (odp->d_flags&DB_F_HINT)) ? " hint":"" );
76	#endif
77	np = nlookup(name, &htp, &fname, newdp != NULL);
78	if (np == NULL \|\| fname != name)
79	return (NONAME);
80
81	/* Reflect certain updates in hint cache also... */
82	/* Don't stick data we are authoritative for in hints. */
83	if (!(flags & DB_NOHINTS) && (odp != NULL) &&
84	(odp->d_zone <= 0) && !(odp->d_flags & DB_F_HINT) &&
85	((name[0] == '\0' && odp->d_type == T_NS) \|\|
86	(odp->d_type == T_A)))
87	{
88	register struct databuf *dp;
89	#ifdef DEBUG
90	if (debug >= 3)
91	fprintf(ddt,"db_update: hint '%s' %d\n",
92	name, odp->d_ttl);
93	#endif
94	dp = savedata(odp->d_class, odp->d_type, odp->d_ttl,
95	odp->d_data, odp->d_size);
96	dp->d_zone = DB_Z_CACHE;
97	dp->d_flags = DB_F_HINT;
98	if (db_update(name, dp,dp, (flags\|DB_NOHINTS), fcachetab) != OK) {
99	#ifdef DEBUG
100	if (debug > 2)
101	fprintf(ddt, "db_update: hint %x freed\n", dp);
102	#endif
103	(void) free((char *)dp);
104	}
105	}
106
107	if (odp != NULL) {
108	pdp = NULL;
109	for (dp = np->n_data; dp != NULL; ) {
110	if (!match(dp, odp->d_class, odp->d_type)) {
111	if ((dp->d_type == T_CNAME \|\|
112	odp->d_type == T_CNAME) &&
113	odp->d_mark == dp->d_mark &&
114	zones[odp->d_zone].z_type != Z_CACHE) {
115	syslog(LOG_ERR,
116	"%s has CNAME and other data (illegal)\n",
117	name);
118	#ifdef DEBUG
119	if (debug)
120	fprintf(ddt,
121	"db_update: %s: CNAME and more (%d, %d)\n",
122	name, odp->d_type, dp->d_type);
123	#endif
124	}
125	goto skip;
126	}
127	#ifdef DEBUG
128	if (debug >= 5)
129	fprintf(ddt,"db_update: flags = %#x, sizes = %d, %d (%d)\n",
130	flags, odp->d_size, dp->d_size,
131	db_cmp(dp, odp));
132	#endif
133	if (flags & DB_NOTAUTH && dp->d_zone) {
134	#ifdef DEBUG
135	if (debug)
136	fprintf(ddt,
137	"%s attempted update to auth zone %d '%s'\n",
138	inet_ntoa(from_addr.sin_addr),
139	dp->d_zone, zones[dp->d_zone].z_origin);
140	#endif
141	return (AUTH);
142	}
143	if ((flags & DB_NODATA) && !db_cmp(dp, odp)) {
144	/* refresh ttl if cache entry */
145	if (dp->d_zone == 0) {
146	if (odp->d_zone != 0) { /* XXX */
147	/* changing cache->auth */
148	dp->d_zone = odp->d_zone;
149	dp->d_ttl = odp->d_ttl;
150	#ifdef DEBUG
151	if (debug > 3)
152	fprintf(ddt,
153	"db_update: cache entry now in auth zone\n");
154	#endif
155	return (DATAEXISTS);
156	}
157	fixttl(odp);
158	if (odp->d_ttl > dp->d_ttl)
159	dp->d_ttl = odp->d_ttl;
160	#ifdef DEBUG
161	if (debug >= 3)
162	fprintf(ddt,"db_update: new ttl %d, +%d\n",
163	dp->d_ttl, dp->d_ttl - tt.tv_sec);
164	#endif
165	}
166	return (DATAEXISTS);
167	}
168	/*
169	* If the old databuf has some data, check that the
170	* data matches that in the new databuf (so UPDATED
171	* will delete only the matching RR)
172	*/
173	if (odp->d_size > 0) {
174	if (db_cmp(dp, odp))
175	goto skip;
176	}
177	foundRR = 1;
178	if (flags & DB_DELETE)
179	dp = rm_datum(dp, np, pdp);
180	else {
181	skip: pdp = dp;
182	dp = dp->d_next;
183	}
184	}
185	if (!foundRR) {
186	if (flags & DB_DELETE)
187	return(NODATA);
188	if (flags & DB_MEXIST)
189	return(NODATA);
190	}
191	}
192	if (newdp == NULL)
193	return (OK);
194	fixttl(newdp);
195	#ifdef DEBUG
196	if (debug >= 3)
197	fprintf(ddt,"db_update: adding%s %x\n",
198	(newdp->d_flags&DB_F_HINT) ? " hint":"", newdp);
199	#endif
200	if (!(newdp->d_flags & DB_F_HINT))
201	addinv(np, newdp); /* modify inverse query tables */
202
203	/* Add to end of list, generally preserving order */
204	newdp->d_next = NULL;
205	if ((dp = np->n_data) == NULL) {
206	np->n_data = newdp;
207	return (OK);
208	}
209	/* XXX: need to check for duplicate WKS records and flag error */
210	while (dp->d_next != NULL) {
211	if ((flags & DB_NODATA) && !db_cmp(dp, newdp))
212	return (DATAEXISTS);
213	dp = dp->d_next;
214	}
215	if ((flags & DB_NODATA) && !db_cmp(dp, newdp))
216	return (DATAEXISTS);
217	dp->d_next = newdp;
218	return (OK);
219	}
220
221	fixttl(dp)
222	register struct databuf *dp;
223	{
224	if (dp->d_zone == 0 && !(dp->d_flags & DB_F_HINT)) {
225	if (dp->d_ttl <= tt.tv_sec)
226	return;
227	else if (dp->d_ttl < tt.tv_sec+min_cache_ttl)
228	dp->d_ttl = tt.tv_sec+min_cache_ttl;
229	else if (dp->d_ttl > tt.tv_sec+max_cache_ttl)
230	dp->d_ttl = tt.tv_sec+max_cache_ttl;
231	}
232	return;
233	}
234
235	struct invbuf invtab[INVHASHSZ]; / Inverse query hash table */
236
237	/*
238	* Add data 'dp' to inverse query tables for name 'np'.
239	*/
240	addinv(np, dp)
241	struct namebuf *np;
242	struct databuf *dp;
243	{
244	register struct invbuf *ip;
245	register int hval, i;
246
247	switch (dp->d_type) {
248	case T_A:
249	case T_UID:
250	case T_GID:
251	break;
252
253	default:
254	return;
255	}
256
257	hval = dhash(dp->d_data, dp->d_size);
258	for (ip = invtab[hval]; ip != NULL; ip = ip->i_next)
259	for (i = 0; i < INVBLKSZ; i++)
260	if (ip->i_dname[i] == NULL) {
261	ip->i_dname[i] = np;
262	return;
263	}
264	ip = saveinv();
265	ip->i_next = invtab[hval];
266	invtab[hval] = ip;
267	ip->i_dname[0] = np;
268	}
269
270	/*
271	* Remove data 'odp' from inverse query table.
272	*/
273	rminv(odp)
274	struct databuf *odp;
275	{
276	register struct invbuf *ip;
277	register struct databuf *dp;
278	struct namebuf *np;
279	register int i;
280
281	for (ip = invtab[dhash(odp->d_data, odp->d_size)]; ip != NULL;
282	ip = ip->i_next) {
283	for (i = 0; i < INVBLKSZ; i++) {
284	if ((np = ip->i_dname[i]) == NULL)
285	break;
286	for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
287	if (!match(dp, odp->d_class, odp->d_type))
288	continue;
289	if (db_cmp(dp, odp))
290	continue;
291	while (i < INVBLKSZ-1) {
292	ip->i_dname[i] = ip->i_dname[i+1];
293	i++;
294	}
295	ip->i_dname[i] = NULL;
296	return;
297	}
298	}
299	}
300	}
301
302	/*
303	* Compute hash value from data.
304	*/
305	dhash(dp, dlen)
306	char *dp;
307	int dlen;
308	{
309	register char *cp;
310	register unsigned hval;
311	register int n;
312
313	n = dlen;
314	if (n > 8)
315	n = 8;
316	hval = 0;
317	for (cp = dp; --n >= 0; ) {
318	hval <<= 1;
319	hval += *cp++;
320	}
321	return (hval % INVHASHSZ);
322	}
323
324	/*
325	* Compare type, class and data from databufs for equivalence.
326	* Must be case insensitive for some domain names.
327	* Return 0 if equivalent, nonzero otherwise.
328	*/
329	db_cmp(dp1, dp2)
330	register struct databuf dp1, dp2;
331
332	{
333	register char cp1, cp2;
334	int len;
335
336	if (dp1->d_type != dp2->d_type \|\| dp1->d_class != dp2->d_class)
337	return(1);
338	if (dp1->d_size != dp2->d_size)
339	return(1);
340	if (dp1->d_mark != dp2->d_mark)
341	return(1); /* old and new RR's are distinct */
342	switch (dp1->d_type) {
343
344	case T_A:
345	case T_UID:
346	case T_GID:
347	case T_WKS:
348	case T_NULL:
349	#ifdef ALLOW_T_UNSPEC
350	case T_UNSPEC:
351	#endif ALLOW_T_UNSPEC
352	return(bcmp(dp1->d_data, dp2->d_data, dp1->d_size));
353
354	case T_NS:
355	case T_CNAME:
356	case T_PTR:
357	case T_MB:
358	case T_MG:
359	case T_MR:
360	case T_UINFO:
361	return(strcasecmp(dp1->d_data, dp2->d_data));
362
363	case T_HINFO:
364	cp1 = dp1->d_data;
365	cp2 = dp2->d_data;
366	len = *cp1;
367	if (strncasecmp(++cp1, ++cp2, len))
368	return(1);
369	cp1 += len;
370	cp2 += len;
371	len = *cp1;
372	return(strncasecmp(++cp1, ++cp2, len));
373
374	case T_SOA:
375	case T_MINFO:
376	if (strcasecmp(dp1->d_data, dp2->d_data))
377	return(1);
378	cp1 = dp1->d_data + strlen(dp1->d_data) + 1;
379	cp2 = dp2->d_data + strlen(dp2->d_data) + 1;
380	if (dp1->d_type != T_SOA)
381	return(strcasecmp(cp1, cp2));
382	if (strcasecmp(cp1, cp2))
383	return(1);
384	cp1 += strlen(cp1) + 1;
385	cp2 += strlen(cp2) + 1;
386	return(bcmp(cp1, cp2, sizeof(u_long) * 5));
387
388	case T_MX:
389	cp1 = dp1->d_data;
390	cp2 = dp2->d_data;
391	if (cp1++ != cp2++ \|\| cp1++ != cp2++) /* cmp prio */
392	return(1);
393	return(strcasecmp(cp1, cp2));
394
395	case T_TXT:
396	if (dp1->d_size != dp2->d_size)
397	return(1);
398	return(bcmp(dp1->d_data, dp2->d_data, dp1->d_size));
399
400	default:
401	return (1);
402	}
403	}