1 /* $OpenBSD: dns64_synth.c,v 1.1 2021/01/24 18:29:15 florian Exp $ */
2
3 /*
4 * dns64/dns64.h - DNS64 module
5 *
6 * Copyright (c) 2009, Viagénie. All rights reserved.
7 *
8 * This software is open source.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 * Redistributions of source code must retain the above copyright notice,
15 * this list of conditions and the following disclaimer.
16 *
17 * Redistributions in binary form must reproduce the above copyright notice,
18 * this list of conditions and the following disclaimer in the documentation
19 * and/or other materials provided with the distribution.
20 *
21 * Neither the name of the NLNET LABS nor the names of its contributors may
22 * be used to endorse or promote products derived from this software without
23 * specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
29 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38 /*
39 * Copyright (c) 2021 Florian Obser <florian@openbsd.org>
40 *
41 * Permission to use, copy, modify, and distribute this software for any
42 * purpose with or without fee is hereby granted, provided that the above
43 * copyright notice and this permission notice appear in all copies.
44 *
45 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
46 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
47 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
48 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
49 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
50 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
51 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
52 */
53
54 #include <sys/types.h>
55 #include <sys/socket.h>
56
57 #include <netinet/in.h>
58 #include <net/route.h>
59
60 #include <string.h>
61
62 #include "libunbound/config.h"
63 #include "libunbound/util/regional.h"
64 #include "libunbound/util/data/msgencode.h"
65 #include "libunbound/util/data/msgparse.h"
66 #include "libunbound/util/data/msgreply.h"
67
68 #include "log.h"
69 #include "unwind.h"
70 #include "frontend.h"
71 #include "dns64_synth.h"
72
73 extern struct dns64_prefix *dns64_prefixes;
74 extern int dns64_prefix_count;
75
76 static void
synthesize_aaaa(const struct in6_addr * in6,int prefixlen,const uint8_t * a,size_t a_len,uint8_t * aaaa,size_t aaaa_len)77 synthesize_aaaa(const struct in6_addr *in6, int prefixlen, const uint8_t *a,
78 size_t a_len, uint8_t *aaaa, size_t aaaa_len)
79 {
80 size_t i, pos;
81 memcpy(aaaa, in6->s6_addr, sizeof(in6->s6_addr));
82 for (i = 0, pos = prefixlen / 8; i < a_len && pos < aaaa_len;
83 i++, pos++) {
84 if (pos == 8)
85 aaaa[pos++] = 0;
86 aaaa[pos] = a[i];
87 }
88 }
89
90 /*
91 * Copied from unbound/dns64/dns64.c and slightly extended to work with more
92 * than one IPv6 prefix.
93 */
94
95 void
dns64_synth_aaaa_data(const struct ub_packed_rrset_key * fk,const struct packed_rrset_data * fd,struct ub_packed_rrset_key * dk,struct packed_rrset_data ** dd_out,struct regional * region)96 dns64_synth_aaaa_data(const struct ub_packed_rrset_key* fk, const struct
97 packed_rrset_data* fd, struct ub_packed_rrset_key *dk, struct
98 packed_rrset_data **dd_out, struct regional *region)
99 {
100 struct packed_rrset_data *dd;
101 size_t i, pos;
102 int j;
103
104 /*
105 * Create synthesized AAAA RR set data. We need to allocated extra
106 * memory for the RRs themselves. Each RR has a length, TTL, pointer to
107 * wireformat data, 2 bytes of data length, and 16 bytes of IPv6
108 * address.
109 */
110 if(fd->count > RR_COUNT_MAX) {
111 *dd_out = NULL;
112 return; /* integer overflow protection in alloc */
113 }
114 if (!(dd = *dd_out = regional_alloc(region, sizeof(struct
115 packed_rrset_data) + fd->count * dns64_prefix_count *
116 (sizeof(size_t) + sizeof(time_t) + sizeof(uint8_t*) + 2 + 16)))) {
117 log_warnx("out of memory");
118 return;
119 }
120
121 /* Copy attributes from A RR set. */
122 dd->ttl = fd->ttl;
123 dd->count = fd->count * dns64_prefix_count;
124 dd->rrsig_count = 0;
125 dd->trust = fd->trust;
126 dd->security = fd->security;
127
128 /* Synthesize AAAA records. Adjust pointers in structure. */
129 dd->rr_len = (size_t*)((uint8_t*)dd + sizeof(struct packed_rrset_data));
130 dd->rr_data = (uint8_t**)&dd->rr_len[dd->count];
131 dd->rr_ttl = (time_t*)&dd->rr_data[dd->count];
132 for(i = 0, pos = 0; i < fd->count; ++i) {
133 if (fd->rr_len[i] != 6 || fd->rr_data[i][0] != 0 ||
134 fd->rr_data[i][1] != 4) {
135 *dd_out = NULL;
136 return;
137 }
138 for (j = 0; j < dns64_prefix_count; j++, pos++) {
139 dd->rr_len[pos] = 18;
140 dd->rr_ttl[pos] = fd->rr_ttl[i];
141 dd->rr_data[pos] = (uint8_t*)&dd->rr_ttl[dd->count] +
142 18 * pos;
143 dd->rr_data[pos][0] = 0;
144 dd->rr_data[pos][1] = 16;
145 synthesize_aaaa(&dns64_prefixes[j].in6,
146 dns64_prefixes[j].prefixlen, &fd->rr_data[i][2],
147 fd->rr_len[i]-2, &dd->rr_data[pos][2],
148 dd->rr_len[pos]-2);
149 }
150 }
151
152 /*
153 * Create synthesized AAAA RR set key. This is mostly just bookkeeping,
154 * nothing interesting here.
155 */
156 if(!dk) {
157 log_warnx("no key");
158 *dd_out = NULL;
159 return;
160 }
161
162 dk->rk.dname = (uint8_t*)regional_alloc_init(region, fk->rk.dname,
163 fk->rk.dname_len);
164
165 if(!dk->rk.dname) {
166 log_warnx("out of memory");
167 *dd_out = NULL;
168 return;
169 }
170
171 dk->rk.type = htons(LDNS_RR_TYPE_AAAA);
172 memset(&dk->entry, 0, sizeof(dk->entry));
173 dk->entry.key = dk;
174 dk->entry.hash = rrset_key_hash(&dk->rk);
175 dk->entry.data = dd;
176 }
177