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@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
res_nupdate(res_state statp,ns_updrec * rrecp_in,ns_tsig_key * key)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
res_dprintf(const char * fmt,...)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