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      1 /*	$NetBSD: res_update.c,v 1.2 2022/04/19 20:32:17 rillig Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
      5  * Copyright (c) 1996-1999 by Internet Software Consortium.
      6  *
      7  * Permission to use, copy, modify, and distribute this software for any
      8  * purpose with or without fee is hereby granted, provided that the above
      9  * copyright notice and this permission notice appear in all copies.
     10  *
     11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
     12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
     14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
     17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     18  */
     19 
     20 /*! \file
     21  * \brief
     22  * Based on the Dynamic DNS reference implementation by Viraj Bais
     23  * <viraj_bais (at) ccm.fm.intel.com>
     24  */
     25 #include <sys/cdefs.h>
     26 #if 0
     27 static const char rcsid[] = "Id: res_update.c,v 1.13 2005/04/27 04:56:43 sra Exp ";
     28 #else
     29 __RCSID("$NetBSD: res_update.c,v 1.2 2022/04/19 20:32:17 rillig Exp $");
     30 #endif
     31 
     32 
     33 #include "port_before.h"
     34 
     35 #include <sys/param.h>
     36 #include <sys/socket.h>
     37 #include <sys/time.h>
     38 
     39 #include <netinet/in.h>
     40 #include <arpa/inet.h>
     41 #include <arpa/nameser.h>
     42 
     43 #include <errno.h>
     44 #include <limits.h>
     45 #include <netdb.h>
     46 #include <res_update.h>
     47 #include <stdarg.h>
     48 #include <stdio.h>
     49 #include <stdlib.h>
     50 #include <string.h>
     51 
     52 #include <isc/list.h>
     53 #include <resolv.h>
     54 
     55 #include "port_after.h"
     56 #include "res_private.h"
     57 
     58 /*%
     59  * Separate a linked list of records into groups so that all records
     60  * in a group will belong to a single zone on the nameserver.
     61  * Create a dynamic update packet for each zone and send it to the
     62  * nameservers for that zone, and await answer.
     63  * Abort if error occurs in updating any zone.
     64  * Return the number of zones updated on success, < 0 on error.
     65  *
     66  * On error, caller must deal with the unsynchronized zones
     67  * eg. an A record might have been successfully added to the forward
     68  * zone but the corresponding PTR record would be missing if error
     69  * was encountered while updating the reverse zone.
     70  */
     71 
     72 struct zonegrp {
     73 	char			z_origin[MAXDNAME];
     74 	ns_class		z_class;
     75 	union res_sockaddr_union z_nsaddrs[MAXNS];
     76 	int			z_nscount;
     77 	int			z_flags;
     78 	TAILQ_HEAD(, ns_updrec)	z_rrlist;
     79 	TAILQ_ENTRY(zonegrp)	z_link;
     80 };
     81 
     82 #define ZG_F_ZONESECTADDED	0x0001
     83 
     84 /* Forward. */
     85 
     86 static void	res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);
     87 
     88 /* Macros. */
     89 
     90 #define DPRINTF(x) do {\
     91 		int save_errno = errno; \
     92 		if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \
     93 		errno = save_errno; \
     94 	} while (0)
     95 
     96 /* Public. */
     97 
     98 int
     99 res_nupdate(res_state statp, ns_updrec *rrecp_in, ns_tsig_key *key) {
    100 	ns_updrec *rrecp;
    101 	u_char answer[PACKETSZ];
    102 	u_char *packet;
    103 	struct zonegrp *zptr, tgrp;
    104 	TAILQ_HEAD(, zonegrp) zgrps;
    105 	int nzones = 0, nscount = 0, n;
    106 	union res_sockaddr_union nsaddrs[MAXNS];
    107 
    108 	packet = malloc(NS_MAXMSG);
    109 	if (packet == NULL) {
    110 		DPRINTF(("malloc failed"));
    111 		return (0);
    112 	}
    113 	/* Thread all of the updates onto a list of groups. */
    114 	TAILQ_INIT(&zgrps);
    115 	memset(&tgrp, 0, sizeof (tgrp));
    116 	for (rrecp = rrecp_in; rrecp; rrecp = TAILQ_NEXT(rrecp, r_link)) {
    117 		int nscnt;
    118 		/* Find the origin for it if there is one. */
    119 		tgrp.z_class = rrecp->r_class;
    120 		nscnt = res_findzonecut2(statp, rrecp->r_dname, tgrp.z_class,
    121 					 RES_EXHAUSTIVE, tgrp.z_origin,
    122 					 sizeof tgrp.z_origin,
    123 					 tgrp.z_nsaddrs, MAXNS);
    124 		if (nscnt <= 0) {
    125 			DPRINTF(("res_findzonecut failed (%d)", nscnt));
    126 			goto done;
    127 		}
    128 		tgrp.z_nscount = nscnt;
    129 		/* Find the group for it if there is one. */
    130 		TAILQ_FOREACH(zptr, &zgrps, z_link)
    131 			if (ns_samename(tgrp.z_origin, zptr->z_origin) == 1 &&
    132 			    tgrp.z_class == zptr->z_class)
    133 				break;
    134 		/* Make a group for it if there isn't one. */
    135 		if (zptr == NULL) {
    136 			zptr = malloc(sizeof *zptr);
    137 			if (zptr == NULL) {
    138 				DPRINTF(("malloc failed"));
    139 				goto done;
    140 			}
    141 			*zptr = tgrp;
    142 			zptr->z_flags = 0;
    143 			TAILQ_INIT(&zptr->z_rrlist);
    144 			TAILQ_INSERT_TAIL(&zgrps, zptr, z_link);
    145 		}
    146 		/* Thread this rrecp onto the right group. */
    147 		TAILQ_INSERT_TAIL(&zptr->z_rrlist, rrecp, r_glink);
    148 	}
    149 
    150 	TAILQ_FOREACH(zptr, &zgrps, z_link) {
    151 		HEADER h;
    152 		/* Construct zone section and prepend it. */
    153 		rrecp = res_mkupdrec(ns_s_zn, zptr->z_origin,
    154 				     (u_int)zptr->z_class, ns_t_soa, 0);
    155 		if (rrecp == NULL) {
    156 			DPRINTF(("res_mkupdrec failed"));
    157 			goto done;
    158 		}
    159 		TAILQ_INSERT_HEAD(&zptr->z_rrlist, rrecp, r_glink);
    160 		zptr->z_flags |= ZG_F_ZONESECTADDED;
    161 
    162 		/* Marshall the update message. */
    163 		n = res_nmkupdate(statp, TAILQ_FIRST(&zptr->z_rrlist),
    164 				  packet, NS_MAXMSG);
    165 		DPRINTF(("res_mkupdate -> %d", n));
    166 		if (n < 0)
    167 			goto done;
    168 
    169 		/* Temporarily replace the resolver's nameserver set. */
    170 		nscount = res_getservers(statp, nsaddrs, MAXNS);
    171 		res_setservers(statp, zptr->z_nsaddrs, zptr->z_nscount);
    172 
    173 		/* Send the update and remember the result. */
    174 		if (key != NULL)
    175 			n = res_nsendsigned(statp, packet, n, key,
    176 					    answer, (int)sizeof answer);
    177 		else
    178 			n = res_nsend(statp, packet, n, answer,
    179 				      (int)sizeof answer);
    180 		if (n < 0) {
    181 			DPRINTF(("res_nsend: send error, n=%d (%s)\n",
    182 				 n, strerror(errno)));
    183 			goto done;
    184 		}
    185 		memcpy(&h, answer, sizeof(h));
    186 		if (h.rcode == NOERROR)
    187 			nzones++;
    188 
    189 		/* Restore resolver's nameserver set. */
    190 		res_setservers(statp, nsaddrs, nscount);
    191 		nscount = 0;
    192 	}
    193  done:
    194 	while (!TAILQ_EMPTY(&zgrps)) {
    195 		zptr = TAILQ_FIRST(&zgrps);
    196 		if ((zptr->z_flags & ZG_F_ZONESECTADDED) != 0)
    197 			res_freeupdrec(TAILQ_FIRST(&zptr->z_rrlist));
    198 		TAILQ_REMOVE(&zgrps, zptr, z_link);
    199 		free(zptr);
    200 	}
    201 	if (nscount != 0)
    202 		res_setservers(statp, nsaddrs, nscount);
    203 
    204 	free(packet);
    205 	return (nzones);
    206 }
    207 
    208 /* Private. */
    209 
    210 static void
    211 res_dprintf(const char *fmt, ...) {
    212 	va_list ap;
    213 
    214 	va_start(ap, fmt);
    215 	fputs(";; res_nupdate: ", stderr);
    216 	vfprintf(stderr, fmt, ap);
    217 	fputc('\n', stderr);
    218 	va_end(ap);
    219 }
    220